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/* SCTP kernel reference Implementation * (C) Copyright IBM Corp. 2001, 2004 * Copyright (c) 1999-2000 Cisco, Inc. * Copyright (c) 1999-2001 Motorola, Inc. * Copyright (c) 2001-2002 Intel Corp. * Copyright (c) 2002 Nokia Corp. * * This file is part of the SCTP kernel reference Implementation * * This is part of the SCTP Linux Kernel Reference Implementation. * * These are the state functions for the state machine. * * The SCTP reference implementation is free software; * you can redistribute it and/or modify it under the terms of * the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * The SCTP reference implementation is distributed in the hope that it * will be useful, but WITHOUT ANY WARRANTY; without even the implied * ************************ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * See the GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with GNU CC; see the file COPYING. If not, write to * the Free Software Foundation, 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. * * Please send any bug reports or fixes you make to the * email address(es): * lksctp developers <lksctp-developers@lists.sourceforge.net> * * Or submit a bug report through the following website: * http://www.sf.net/projects/lksctp * * Written or modified by: * La Monte H.P. Yarroll <piggy@acm.org> * Karl Knutson <karl@athena.chicago.il.us> * Mathew Kotowsky <kotowsky@sctp.org> * Sridhar Samudrala <samudrala@us.ibm.com> * Jon Grimm <jgrimm@us.ibm.com> * Hui Huang <hui.huang@nokia.com> * Dajiang Zhang <dajiang.zhang@nokia.com> * Daisy Chang <daisyc@us.ibm.com> * Ardelle Fan <ardelle.fan@intel.com> * Ryan Layer <rmlayer@us.ibm.com> * Kevin Gao <kevin.gao@intel.com> * * Any bugs reported given to us we will try to fix... any fixes shared will * be incorporated into the next SCTP release. */ #include <linux/types.h> #include <linux/kernel.h> #include <linux/ip.h> #include <linux/ipv6.h> #include <linux/net.h> #include <linux/inet.h> #include <net/sock.h> #include <net/inet_ecn.h> #include <linux/skbuff.h> #include <net/sctp/sctp.h> #include <net/sctp/sm.h> #include <net/sctp/structs.h> /********************************************************** * These are the state functions for handling chunk events. **********************************************************/ /* * Process the final SHUTDOWN COMPLETE. * * Section: 4 (C) (diagram), 9.2 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint * should stop the T2-shutdown timer and remove all knowledge of the * association (and thus the association enters the CLOSED state). * * Verification Tag: 8.5.1(C) * C) Rules for packet carrying SHUTDOWN COMPLETE: * ... * - The receiver of a SHUTDOWN COMPLETE shall accept the packet if the * Verification Tag field of the packet matches its own tag OR it is * set to its peer's tag and the T bit is set in the Chunk Flags. * Otherwise, the receiver MUST silently discard the packet and take * no further action. An endpoint MUST ignore the SHUTDOWN COMPLETE if * it is not in the SHUTDOWN-ACK-SENT state. * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_do_4_C(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; struct sctp_ulpevent *ev; /* RFC 2960 6.10 Bundling * * An endpoint MUST NOT bundle INIT, INIT ACK or * SHUTDOWN COMPLETE with any other chunks. */ if (!chunk->singleton) return SCTP_DISPOSITION_VIOLATION; if (!sctp_vtag_verify_either(chunk, asoc)) return sctp_sf_pdiscard(ep, asoc, type, arg, commands); /* RFC 2960 10.2 SCTP-to-ULP * * H) SHUTDOWN COMPLETE notification * * When SCTP completes the shutdown procedures (section 9.2) this * notification is passed to the upper layer. */ ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 0, 0, 0, GFP_ATOMIC); if (!ev) goto nomem; sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint * will verify that it is in SHUTDOWN-ACK-SENT state, if it is * not the chunk should be discarded. If the endpoint is in * the SHUTDOWN-ACK-SENT state the endpoint should stop the * T2-shutdown timer and remove all knowledge of the * association (and thus the association enters the CLOSED * state). */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_CLOSED)); SCTP_INC_STATS(SctpShutdowns); SCTP_DEC_STATS(SctpCurrEstab); sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); return SCTP_DISPOSITION_DELETE_TCB; nomem: return SCTP_DISPOSITION_NOMEM; } /* * Respond to a normal INIT chunk. * We are the side that is being asked for an association. * * Section: 5.1 Normal Establishment of an Association, B * B) "Z" shall respond immediately with an INIT ACK chunk. The * destination IP address of the INIT ACK MUST be set to the source * IP address of the INIT to which this INIT ACK is responding. In * the response, besides filling in other parameters, "Z" must set the * Verification Tag field to Tag_A, and also provide its own * Verification Tag (Tag_Z) in the Initiate Tag field. * * Verification Tag: No checking. * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_do_5_1B_init(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; struct sctp_chunk *repl; struct sctp_association *new_asoc; struct sctp_chunk *err_chunk; struct sctp_packet *packet; sctp_unrecognized_param_t *unk_param; struct sock *sk; int len; /* 6.10 Bundling * An endpoint MUST NOT bundle INIT, INIT ACK or * SHUTDOWN COMPLETE with any other chunks. */ if (!chunk->singleton) return SCTP_DISPOSITION_VIOLATION; /* If the packet is an OOTB packet which is temporarily on the * control endpoint, respond with an ABORT. */ if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); sk = ep->base.sk; /* If the endpoint is not listening or if the number of associations * on the TCP-style socket exceed the max backlog, respond with an * ABORT. */ if (!sctp_sstate(sk, LISTENING) || (sctp_style(sk, TCP) && (sk->sk_ack_backlog >= sk->sk_max_ack_backlog))) return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); /* Verify the INIT chunk before processing it. */ err_chunk = NULL; if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, &err_chunk)) { /* This chunk contains fatal error. It is to be discarded. * Send an ABORT, with causes if there is any. */ if (err_chunk) { packet = sctp_abort_pkt_new(ep, asoc, arg, (__u8 *)(err_chunk->chunk_hdr) + sizeof(sctp_chunkhdr_t), ntohs(err_chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t)); sctp_chunk_free(err_chunk); if (packet) { sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet)); SCTP_INC_STATS(SctpOutCtrlChunks); return SCTP_DISPOSITION_CONSUME; } else { return SCTP_DISPOSITION_NOMEM; } } else { return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); } } /* Grab the INIT header. */ chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data; /* Tag the variable length parameters. */ chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); if (!new_asoc) goto nomem; /* The call, sctp_process_init(), can fail on memory allocation. */ if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, sctp_source(chunk), (sctp_init_chunk_t *)chunk->chunk_hdr, GFP_ATOMIC)) goto nomem_init; sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); /* B) "Z" shall respond immediately with an INIT ACK chunk. */ /* If there are errors need to be reported for unknown parameters, * make sure to reserve enough room in the INIT ACK for them. */ len = 0; if (err_chunk) len = ntohs(err_chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0) goto nomem_ack; repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); if (!repl) goto nomem_ack; /* If there are errors need to be reported for unknown parameters, * include them in the outgoing INIT ACK as "Unrecognized parameter" * parameter. */ if (err_chunk) { /* Get the "Unrecognized parameter" parameter(s) out of the * ERROR chunk generated by sctp_verify_init(). Since the * error cause code for "unknown parameter" and the * "Unrecognized parameter" type is the same, we can * construct the parameters in INIT ACK by copying the * ERROR causes over. */ unk_param = (sctp_unrecognized_param_t *) ((__u8 *)(err_chunk->chunk_hdr) + sizeof(sctp_chunkhdr_t)); /* Replace the cause code with the "Unrecognized parameter" * parameter type. */ sctp_addto_chunk(repl, len, unk_param); sctp_chunk_free(err_chunk); } sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); /* * Note: After sending out INIT ACK with the State Cookie parameter, * "Z" MUST NOT allocate any resources, nor keep any states for the * new association. Otherwise, "Z" will be vulnerable to resource * attacks. */ sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); return SCTP_DISPOSITION_DELETE_TCB; nomem_ack: if (err_chunk) sctp_chunk_free(err_chunk); nomem_init: sctp_association_free(new_asoc); nomem: return SCTP_DISPOSITION_NOMEM; } /* * Respond to a normal INIT ACK chunk. * We are the side that is initiating the association. * * Section: 5.1 Normal Establishment of an Association, C * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init * timer and leave COOKIE-WAIT state. "A" shall then send the State * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start * the T1-cookie timer, and enter the COOKIE-ECHOED state. * * Note: The COOKIE ECHO chunk can be bundled with any pending outbound * DATA chunks, but it MUST be the first chunk in the packet and * until the COOKIE ACK is returned the sender MUST NOT send any * other packets to the peer. * * Verification Tag: 3.3.3 * If the value of the Initiate Tag in a received INIT ACK chunk is * found to be 0, the receiver MUST treat it as an error and close the * association by transmitting an ABORT. * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_do_5_1C_ack(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; sctp_init_chunk_t *initchunk; __u32 init_tag; struct sctp_chunk *err_chunk; struct sctp_packet *packet; sctp_disposition_t ret; /* 6.10 Bundling * An endpoint MUST NOT bundle INIT, INIT ACK or * SHUTDOWN COMPLETE with any other chunks. */ if (!chunk->singleton) return SCTP_DISPOSITION_VIOLATION; /* Grab the INIT header. */ chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; init_tag = ntohl(chunk->subh.init_hdr->init_tag); /* Verification Tag: 3.3.3 * If the value of the Initiate Tag in a received INIT ACK * chunk is found to be 0, the receiver MUST treat it as an * error and close the association by transmitting an ABORT. */ if (!init_tag) { struct sctp_chunk *reply = sctp_make_abort(asoc, chunk, 0); if (!reply) goto nomem; sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_CLOSED)); SCTP_INC_STATS(SctpAborteds); sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); return SCTP_DISPOSITION_DELETE_TCB; } /* Verify the INIT chunk before processing it. */ err_chunk = NULL; if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, &err_chunk)) { SCTP_INC_STATS(SctpAborteds); /* This chunk contains fatal error. It is to be discarded. * Send an ABORT, with causes if there is any. */ if (err_chunk) { packet = sctp_abort_pkt_new(ep, asoc, arg, (__u8 *)(err_chunk->chunk_hdr) + sizeof(sctp_chunkhdr_t), ntohs(err_chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t)); sctp_chunk_free(err_chunk); if (packet) { sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet)); SCTP_INC_STATS(SctpOutCtrlChunks); sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_CLOSED)); sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); return SCTP_DISPOSITION_CONSUME; } else { sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_CLOSED)); sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); return SCTP_DISPOSITION_NOMEM; } } else { ret = sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_CLOSED)); sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); return ret; } } /* Tag the variable length parameters. Note that we never * convert the parameters in an INIT chunk. */ chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr; sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, SCTP_PEER_INIT(initchunk)); /* 5.1 C) "A" shall stop the T1-init timer and leave * COOKIE-WAIT state. "A" shall then ... start the T1-cookie * timer, and enter the COOKIE-ECHOED state. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); sctp_add_cmd_sf(commands, SCTP_CMD_COUNTER_RESET, SCTP_COUNTER(SCTP_COUNTER_INIT_ERROR)); sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); /* 5.1 C) "A" shall then send the State Cookie received in the * INIT ACK chunk in a COOKIE ECHO chunk, ... */ /* If there is any errors to report, send the ERROR chunk generated * for unknown parameters as well. */ sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, SCTP_CHUNK(err_chunk)); return SCTP_DISPOSITION_CONSUME; nomem: return SCTP_DISPOSITION_NOMEM; } /* * Respond to a normal COOKIE ECHO chunk. * We are the side that is being asked for an association. * * Section: 5.1 Normal Establishment of an Association, D * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply * with a COOKIE ACK chunk after building a TCB and moving to * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK * chunk MUST be the first chunk in the packet. * * IMPLEMENTATION NOTE: An implementation may choose to send the * Communication Up notification to the SCTP user upon reception * of a valid COOKIE ECHO chunk. * * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules * D) Rules for packet carrying a COOKIE ECHO * * - When sending a COOKIE ECHO, the endpoint MUST use the value of the * Initial Tag received in the INIT ACK. * * - The receiver of a COOKIE ECHO follows the procedures in Section 5. * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_do_5_1D_ce(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; struct sctp_association *new_asoc; sctp_init_chunk_t *peer_init; struct sctp_chunk *repl; struct sctp_ulpevent *ev; int error = 0; struct sctp_chunk *err_chk_p; /* If the packet is an OOTB packet which is temporarily on the * control endpoint, respond with an ABORT. */ if (ep == sctp_sk((sctp_get_ctl_sock()))->ep) return sctp_sf_ootb(ep, asoc, type, arg, commands); /* "Decode" the chunk. We have no optional parameters so we * are in good shape. */ chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; skb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t)); /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint * "Z" will reply with a COOKIE ACK chunk after building a TCB * and moving to the ESTABLISHED state. */ new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, &err_chk_p); /* FIXME: * If the re-build failed, what is the proper error path * from here? * * [We should abort the association. --piggy] */ if (!new_asoc) { /* FIXME: Several errors are possible. A bad cookie should * be silently discarded, but think about logging it too. */ switch (error) { case -SCTP_IERROR_NOMEM: goto nomem; case -SCTP_IERROR_STALE_COOKIE: sctp_send_stale_cookie_err(ep, asoc, chunk, commands, err_chk_p); return sctp_sf_pdiscard(ep, asoc, type, arg, commands); case -SCTP_IERROR_BAD_SIG: default: return sctp_sf_pdiscard(ep, asoc, type, arg, commands); }; } sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_ESTABLISHED)); SCTP_INC_STATS(SctpCurrEstab); SCTP_INC_STATS(SctpPassiveEstabs); sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); if (new_asoc->autoclose) sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); /* Re-build the bind address for the association is done in * the sctp_unpack_cookie() already. */ /* This is a brand-new association, so these are not yet side * effects--it is safe to run them here. */ peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, &chunk->subh.cookie_hdr->c.peer_addr, peer_init, GFP_ATOMIC)) goto nomem_init; repl = sctp_make_cookie_ack(new_asoc, chunk); if (!repl) goto nomem_repl; sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); /* RFC 2960 5.1 Normal Establishment of an Association * * D) IMPLEMENTATION NOTE: An implementation may choose to * send the Communication Up notification to the SCTP user * upon reception of a valid COOKIE ECHO chunk. */ ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, new_asoc->c.sinit_num_ostreams, new_asoc->c.sinit_max_instreams, GFP_ATOMIC); if (!ev) goto nomem_ev; sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); return SCTP_DISPOSITION_CONSUME; nomem_ev: sctp_chunk_free(repl); nomem_repl: nomem_init: sctp_association_free(new_asoc); nomem: return SCTP_DISPOSITION_NOMEM; } /* * Respond to a normal COOKIE ACK chunk. * We are the side that is being asked for an association. * * RFC 2960 5.1 Normal Establishment of an Association * * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie * timer. It may also notify its ULP about the successful * establishment of the association with a Communication Up * notification (see Section 10). * * Verification Tag: * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_do_5_1E_ca(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_ulpevent *ev; /* RFC 2960 5.1 Normal Establishment of an Association * * E) Upon reception of the COOKIE ACK, endpoint "A" will move * from the COOKIE-ECHOED state to the ESTABLISHED state, * stopping the T1-cookie timer. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_ESTABLISHED)); SCTP_INC_STATS(SctpCurrEstab); SCTP_INC_STATS(SctpActiveEstabs); sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); if (asoc->autoclose) sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); /* It may also notify its ULP about the successful * establishment of the association with a Communication Up * notification (see Section 10). */ ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 0, asoc->c.sinit_num_ostreams, asoc->c.sinit_max_instreams, GFP_ATOMIC); if (!ev) goto nomem; sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); return SCTP_DISPOSITION_CONSUME; nomem: return SCTP_DISPOSITION_NOMEM; } /* Generate and sendout a heartbeat packet. */ sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_transport *transport = (struct sctp_transport *) arg; struct sctp_chunk *reply; sctp_sender_hb_info_t hbinfo; size_t paylen = 0; hbinfo.param_hdr.type = SCTP_PARAM_HEARTBEAT_INFO; hbinfo.param_hdr.length = htons(sizeof(sctp_sender_hb_info_t)); hbinfo.daddr = transport->ipaddr; hbinfo.sent_at = jiffies; /* Send a heartbeat to our peer. */ paylen = sizeof(sctp_sender_hb_info_t); reply = sctp_make_heartbeat(asoc, transport, &hbinfo, paylen); if (!reply) return SCTP_DISPOSITION_NOMEM; /* Set rto_pending indicating that an RTT measurement * is started with this heartbeat chunk. */ sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, SCTP_TRANSPORT(transport)); sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); return SCTP_DISPOSITION_CONSUME; } /* Generate a HEARTBEAT packet on the given transport. */ sctp_disposition_t sctp_sf_sendbeat_8_3(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_transport *transport = (struct sctp_transport *) arg; if (asoc->overall_error_count > asoc->max_retrans) { /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_U32(SCTP_ERROR_NO_ERROR)); SCTP_INC_STATS(SctpAborteds); SCTP_DEC_STATS(SctpCurrEstab); return SCTP_DISPOSITION_DELETE_TCB; } /* Section 3.3.5. * The Sender-specific Heartbeat Info field should normally include * information about the sender's current time when this HEARTBEAT * chunk is sent and the destination transport address to which this * HEARTBEAT is sent (see Section 8.3). */ if (transport->hb_allowed) { if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, arg, commands)) return SCTP_DISPOSITION_NOMEM; /* Set transport error counter and association error counter * when sending heartbeat. */ sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_RESET, SCTP_TRANSPORT(transport)); } sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, SCTP_TRANSPORT(transport)); return SCTP_DISPOSITION_CONSUME; } /* * Process an heartbeat request. * * Section: 8.3 Path Heartbeat * The receiver of the HEARTBEAT should immediately respond with a * HEARTBEAT ACK that contains the Heartbeat Information field copied * from the received HEARTBEAT chunk. * * Verification Tag: 8.5 Verification Tag [Normal verification] * When receiving an SCTP packet, the endpoint MUST ensure that the * value in the Verification Tag field of the received SCTP packet * matches its own Tag. If the received Verification Tag value does not * match the receiver's own tag value, the receiver shall silently * discard the packet and shall not process it any further except for * those cases listed in Section 8.5.1 below. * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_beat_8_3(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; struct sctp_chunk *reply; size_t paylen = 0; /* 8.5 When receiving an SCTP packet, the endpoint MUST ensure * that the value in the Verification Tag field of the * received SCTP packet matches its own Tag. If the received * Verification Tag value does not match the receiver's own * tag value, the receiver shall silently discard the packet... */ if (ntohl(chunk->sctp_hdr->vtag) != asoc->c.my_vtag) return sctp_sf_pdiscard(ep, asoc, type, arg, commands); /* 8.3 The receiver of the HEARTBEAT should immediately * respond with a HEARTBEAT ACK that contains the Heartbeat * Information field copied from the received HEARTBEAT chunk. */ chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data; paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); skb_pull(chunk->skb, paylen); reply = sctp_make_heartbeat_ack(asoc, chunk, chunk->subh.hb_hdr, paylen); if (!reply) goto nomem; sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); return SCTP_DISPOSITION_CONSUME; nomem: return SCTP_DISPOSITION_NOMEM; } /* * Process the returning HEARTBEAT ACK. * * Section: 8.3 Path Heartbeat * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT * should clear the error counter of the destination transport * address to which the HEARTBEAT was sent, and mark the destination * transport address as active if it is not so marked. The endpoint may * optionally report to the upper layer when an inactive destination * address is marked as active due to the reception of the latest * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also * clear the association overall error count as well (as defined * in section 8.1). * * The receiver of the HEARTBEAT ACK should also perform an RTT * measurement for that destination transport address using the time * value carried in the HEARTBEAT ACK chunk. * * Verification Tag: 8.5 Verification Tag [Normal verification] * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_backbeat_8_3(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; union sctp_addr from_addr; struct sctp_transport *link; sctp_sender_hb_info_t *hbinfo; unsigned long max_interval; /* 8.5 When receiving an SCTP packet, the endpoint MUST ensure * that the value in the Verification Tag field of the * received SCTP packet matches its own Tag. ... */ if (ntohl(chunk->sctp_hdr->vtag) != asoc->c.my_vtag) return sctp_sf_pdiscard(ep, asoc, type, arg, commands); hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data; from_addr = hbinfo->daddr; link = sctp_assoc_lookup_paddr(asoc, &from_addr); /* This should never happen, but lets log it if so. */ if (!link) { printk(KERN_WARNING "%s: Could not find address %d.%d.%d.%d\n", __FUNCTION__, NIPQUAD(from_addr.v4.sin_addr)); return SCTP_DISPOSITION_DISCARD; } max_interval = link->hb_interval + link->rto; /* Check if the timestamp looks valid. */ if (time_after(hbinfo->sent_at, jiffies) || time_after(jiffies, hbinfo->sent_at + max_interval)) { SCTP_DEBUG_PRINTK("%s: HEARTBEAT ACK with invalid timestamp" "received for transport: %p\n", __FUNCTION__, link); return SCTP_DISPOSITION_DISCARD; } /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of * the HEARTBEAT should clear the error counter of the * destination transport address to which the HEARTBEAT was * sent and mark the destination transport address as active if * it is not so marked. */ sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); return SCTP_DISPOSITION_CONSUME; } /* Helper function to send out an abort for the restart * condition. */ static int sctp_sf_send_restart_abort(union sctp_addr *ssa, struct sctp_chunk *init, sctp_cmd_seq_t *commands) { int len; struct sctp_packet *pkt; union sctp_addr_param *addrparm; struct sctp_errhdr *errhdr; struct sctp_endpoint *ep; char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)]; struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); /* Build the error on the stack. We are way to malloc crazy * throughout the code today. */ errhdr = (struct sctp_errhdr *)buffer; addrparm = (union sctp_addr_param *)errhdr->variable; /* Copy into a parm format. */ len = af->to_addr_param(ssa, addrparm); len += sizeof(sctp_errhdr_t); errhdr->cause = SCTP_ERROR_RESTART; errhdr->length = htons(len); /* Assign to the control socket. */ ep = sctp_sk((sctp_get_ctl_sock()))->ep; /* Association is NULL since this may be a restart attack and we * want to send back the attacker's vtag. */ pkt = sctp_abort_pkt_new(ep, NULL, init, errhdr, len); if (!pkt) goto out; sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); SCTP_INC_STATS(SctpOutCtrlChunks); /* Discard the rest of the inbound packet. */ sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); out: /* Even if there is no memory, treat as a failure so * the packet will get dropped. */ return 0; } /* A restart is occurring, check to make sure no new addresses * are being added as we may be under a takeover attack. */ static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, const struct sctp_association *asoc, struct sctp_chunk *init, sctp_cmd_seq_t *commands) { struct sctp_transport *new_addr, *addr; struct list_head *pos, *pos2; int found; /* Implementor's Guide - Sectin 5.2.2 * ... * Before responding the endpoint MUST check to see if the * unexpected INIT adds new addresses to the association. If new * addresses are added to the association, the endpoint MUST respond * with an ABORT.. */ /* Search through all current addresses and make sure * we aren't adding any new ones. */ new_addr = 0; found = 0; list_for_each(pos, &new_asoc->peer.transport_addr_list) { new_addr = list_entry(pos, struct sctp_transport, transports); found = 0; list_for_each(pos2, &asoc->peer.transport_addr_list) { addr = list_entry(pos2, struct sctp_transport, transports); if (sctp_cmp_addr_exact(&new_addr->ipaddr, &addr->ipaddr)) { found = 1; break; } } if (!found) break; } /* If a new address was added, ABORT the sender. */ if (!found && new_addr) { sctp_sf_send_restart_abort(&new_addr->ipaddr, init, commands); } /* Return success if all addresses were found. */ return found; } /* Populate the verification/tie tags based on overlapping INIT * scenario. * * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. */ static void sctp_tietags_populate(struct sctp_association *new_asoc, const struct sctp_association *asoc) { switch (asoc->state) { /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ case SCTP_STATE_COOKIE_WAIT: new_asoc->c.my_vtag = asoc->c.my_vtag; new_asoc->c.my_ttag = asoc->c.my_vtag; new_asoc->c.peer_ttag = 0; break; case SCTP_STATE_COOKIE_ECHOED: new_asoc->c.my_vtag = asoc->c.my_vtag; new_asoc->c.my_ttag = asoc->c.my_vtag; new_asoc->c.peer_ttag = asoc->c.peer_vtag; break; /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, * COOKIE-WAIT and SHUTDOWN-ACK-SENT */ default: new_asoc->c.my_ttag = asoc->c.my_vtag; new_asoc->c.peer_ttag = asoc->c.peer_vtag; break; }; /* Other parameters for the endpoint SHOULD be copied from the * existing parameters of the association (e.g. number of * outbound streams) into the INIT ACK and cookie. */ new_asoc->rwnd = asoc->rwnd; new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; new_asoc->c.initial_tsn = asoc->c.initial_tsn; } /* * Compare vtag/tietag values to determine unexpected COOKIE-ECHO * handling action. * * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. * * Returns value representing action to be taken. These action values * correspond to Action/Description values in RFC 2960, Table 2. */ static char sctp_tietags_compare(struct sctp_association *new_asoc, const struct sctp_association *asoc) { /* In this case, the peer may have restarted. */ if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && (asoc->c.my_vtag == new_asoc->c.my_ttag) && (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) return 'A'; /* Collision case B. */ if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || (0 == asoc->c.peer_vtag))) { return 'B'; } /* Collision case D. */ if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) return 'D'; /* Collision case C. */ if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && (0 == new_asoc->c.my_ttag) && (0 == new_asoc->c.peer_ttag)) return 'C'; /* No match to any of the special cases; discard this packet. */ return 'E'; } /* Common helper routine for both duplicate and simulataneous INIT * chunk handling. */ static sctp_disposition_t sctp_sf_do_unexpected_init( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { sctp_disposition_t retval; struct sctp_chunk *chunk = arg; struct sctp_chunk *repl; struct sctp_association *new_asoc; struct sctp_chunk *err_chunk; struct sctp_packet *packet; sctp_unrecognized_param_t *unk_param; int len; /* 6.10 Bundling * An endpoint MUST NOT bundle INIT, INIT ACK or * SHUTDOWN COMPLETE with any other chunks. */ if (!chunk->singleton) return SCTP_DISPOSITION_VIOLATION; /* Grab the INIT header. */ chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data; /* Tag the variable length parameters. */ chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t)); /* Verify the INIT chunk before processing it. */ err_chunk = NULL; if (!sctp_verify_init(asoc, chunk->chunk_hdr->type, (sctp_init_chunk_t *)chunk->chunk_hdr, chunk, &err_chunk)) { /* This chunk contains fatal error. It is to be discarded. * Send an ABORT, with causes if there is any. */ if (err_chunk) { packet = sctp_abort_pkt_new(ep, asoc, arg, (__u8 *)(err_chunk->chunk_hdr) + sizeof(sctp_chunkhdr_t), ntohs(err_chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t)); if (packet) { sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet)); SCTP_INC_STATS(SctpOutCtrlChunks); retval = SCTP_DISPOSITION_CONSUME; } else { retval = SCTP_DISPOSITION_NOMEM; } goto cleanup; } else { return sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); } } /* * Other parameters for the endpoint SHOULD be copied from the * existing parameters of the association (e.g. number of * outbound streams) into the INIT ACK and cookie. * FIXME: We are copying parameters from the endpoint not the * association. */ new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); if (!new_asoc) goto nomem; /* In the outbound INIT ACK the endpoint MUST copy its current * Verification Tag and Peers Verification tag into a reserved * place (local tie-tag and per tie-tag) within the state cookie. */ if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, sctp_source(chunk), (sctp_init_chunk_t *)chunk->chunk_hdr, GFP_ATOMIC)) { retval = SCTP_DISPOSITION_NOMEM; goto nomem_init; } /* Make sure no new addresses are being added during the * restart. Do not do this check for COOKIE-WAIT state, * since there are no peer addresses to check against. * Upon return an ABORT will have been sent if needed. */ if (!sctp_state(asoc, COOKIE_WAIT)) { if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { retval = SCTP_DISPOSITION_CONSUME; goto cleanup_asoc; } } sctp_tietags_populate(new_asoc, asoc); /* B) "Z" shall respond immediately with an INIT ACK chunk. */ /* If there are errors need to be reported for unknown parameters, * make sure to reserve enough room in the INIT ACK for them. */ len = 0; if (err_chunk) { len = ntohs(err_chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t); } if (sctp_assoc_set_bind_addr_from_ep(new_asoc, GFP_ATOMIC) < 0) goto nomem; repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); if (!repl) goto nomem; /* If there are errors need to be reported for unknown parameters, * include them in the outgoing INIT ACK as "Unrecognized parameter" * parameter. */ if (err_chunk) { /* Get the "Unrecognized parameter" parameter(s) out of the * ERROR chunk generated by sctp_verify_init(). Since the * error cause code for "unknown parameter" and the * "Unrecognized parameter" type is the same, we can * construct the parameters in INIT ACK by copying the * ERROR causes over. */ unk_param = (sctp_unrecognized_param_t *) ((__u8 *)(err_chunk->chunk_hdr) + sizeof(sctp_chunkhdr_t)); /* Replace the cause code with the "Unrecognized parameter" * parameter type. */ sctp_addto_chunk(repl, len, unk_param); } sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); /* * Note: After sending out INIT ACK with the State Cookie parameter, * "Z" MUST NOT allocate any resources for this new association. * Otherwise, "Z" will be vulnerable to resource attacks. */ sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); retval = SCTP_DISPOSITION_CONSUME; cleanup: if (err_chunk) sctp_chunk_free(err_chunk); return retval; nomem: retval = SCTP_DISPOSITION_NOMEM; goto cleanup; nomem_init: cleanup_asoc: sctp_association_free(new_asoc); goto cleanup; } /* * Handle simultanous INIT. * This means we started an INIT and then we got an INIT request from * our peer. * * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) * This usually indicates an initialization collision, i.e., each * endpoint is attempting, at about the same time, to establish an * association with the other endpoint. * * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an * endpoint MUST respond with an INIT ACK using the same parameters it * sent in its original INIT chunk (including its Verification Tag, * unchanged). These original parameters are combined with those from the * newly received INIT chunk. The endpoint shall also generate a State * Cookie with the INIT ACK. The endpoint uses the parameters sent in its * INIT to calculate the State Cookie. * * After that, the endpoint MUST NOT change its state, the T1-init * timer shall be left running and the corresponding TCB MUST NOT be * destroyed. The normal procedures for handling State Cookies when * a TCB exists will resolve the duplicate INITs to a single association. * * For an endpoint that is in the COOKIE-ECHOED state it MUST populate * its Tie-Tags with the Tag information of itself and its peer (see * section 5.2.2 for a description of the Tie-Tags). * * Verification Tag: Not explicit, but an INIT can not have a valid * verification tag, so we skip the check. * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_do_5_2_1_siminit(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { /* Call helper to do the real work for both simulataneous and * duplicate INIT chunk handling. */ return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); } /* * Handle duplicated INIT messages. These are usually delayed * restransmissions. * * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, * COOKIE-ECHOED and COOKIE-WAIT * * Unless otherwise stated, upon reception of an unexpected INIT for * this association, the endpoint shall generate an INIT ACK with a * State Cookie. In the outbound INIT ACK the endpoint MUST copy its * current Verification Tag and peer's Verification Tag into a reserved * place within the state cookie. We shall refer to these locations as * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet * containing this INIT ACK MUST carry a Verification Tag value equal to * the Initiation Tag found in the unexpected INIT. And the INIT ACK * MUST contain a new Initiation Tag (randomly generated see Section * 5.3.1). Other parameters for the endpoint SHOULD be copied from the * existing parameters of the association (e.g. number of outbound * streams) into the INIT ACK and cookie. * * After sending out the INIT ACK, the endpoint shall take no further * actions, i.e., the existing association, including its current state, * and the corresponding TCB MUST NOT be changed. * * Note: Only when a TCB exists and the association is not in a COOKIE- * WAIT state are the Tie-Tags populated. For a normal association INIT * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be * set to 0 (indicating that no previous TCB existed). The INIT ACK and * State Cookie are populated as specified in section 5.2.1. * * Verification Tag: Not specified, but an INIT has no way of knowing * what the verification tag could be, so we ignore it. * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_do_5_2_2_dupinit(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { /* Call helper to do the real work for both simulataneous and * duplicate INIT chunk handling. */ return sctp_sf_do_unexpected_init(ep, asoc, type, arg, commands); } /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') * * Section 5.2.4 * A) In this case, the peer may have restarted. */ static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep, const struct sctp_association *asoc, struct sctp_chunk *chunk, sctp_cmd_seq_t *commands, struct sctp_association *new_asoc) { sctp_init_chunk_t *peer_init; struct sctp_ulpevent *ev; struct sctp_chunk *repl; /* new_asoc is a brand-new association, so these are not yet * side effects--it is safe to run them here. */ peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, sctp_source(chunk), peer_init, GFP_ATOMIC)) goto nomem; /* Make sure no new addresses are being added during the * restart. Though this is a pretty complicated attack * since you'd have to get inside the cookie. */ if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) { return SCTP_DISPOSITION_CONSUME; } /* For now, fail any unsent/unacked data. Consider the optional * choice of resending of this data. */ sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); /* Update the content of current association. */ sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); repl = sctp_make_cookie_ack(new_asoc, chunk); if (!repl) goto nomem; sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); /* Report association restart to upper layer. */ ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, new_asoc->c.sinit_num_ostreams, new_asoc->c.sinit_max_instreams, GFP_ATOMIC); if (!ev) goto nomem_ev; sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); return SCTP_DISPOSITION_CONSUME; nomem_ev: sctp_chunk_free(repl); nomem: return SCTP_DISPOSITION_NOMEM; } /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') * * Section 5.2.4 * B) In this case, both sides may be attempting to start an association * at about the same time but the peer endpoint started its INIT * after responding to the local endpoint's INIT */ /* This case represents an initialization collision. */ static sctp_disposition_t sctp_sf_do_dupcook_b(const struct sctp_endpoint *ep, const struct sctp_association *asoc, struct sctp_chunk *chunk, sctp_cmd_seq_t *commands, struct sctp_association *new_asoc) { sctp_init_chunk_t *peer_init; struct sctp_ulpevent *ev; struct sctp_chunk *repl; /* new_asoc is a brand-new association, so these are not yet * side effects--it is safe to run them here. */ peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; if (!sctp_process_init(new_asoc, chunk->chunk_hdr->type, sctp_source(chunk), peer_init, GFP_ATOMIC)) goto nomem; /* Update the content of current association. */ sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_ESTABLISHED)); SCTP_INC_STATS(SctpCurrEstab); sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); repl = sctp_make_cookie_ack(new_asoc, chunk); if (!repl) goto nomem; sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); /* RFC 2960 5.1 Normal Establishment of an Association * * D) IMPLEMENTATION NOTE: An implementation may choose to * send the Communication Up notification to the SCTP user * upon reception of a valid COOKIE ECHO chunk. */ ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 0, new_asoc->c.sinit_num_ostreams, new_asoc->c.sinit_max_instreams, GFP_ATOMIC); if (!ev) goto nomem_ev; sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); return SCTP_DISPOSITION_CONSUME; nomem_ev: sctp_chunk_free(repl); nomem: return SCTP_DISPOSITION_NOMEM; } /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') * * Section 5.2.4 * C) In this case, the local endpoint's cookie has arrived late. * Before it arrived, the local endpoint sent an INIT and received an * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag * but a new tag of its own. */ /* This case represents an initialization collision. */ static sctp_disposition_t sctp_sf_do_dupcook_c(const struct sctp_endpoint *ep, const struct sctp_association *asoc, struct sctp_chunk *chunk, sctp_cmd_seq_t *commands, struct sctp_association *new_asoc) { /* The cookie should be silently discarded. * The endpoint SHOULD NOT change states and should leave * any timers running. */ return SCTP_DISPOSITION_DISCARD; } /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') * * Section 5.2.4 * * D) When both local and remote tags match the endpoint should always * enter the ESTABLISHED state, if it has not already done so. */ /* This case represents an initialization collision. */ static sctp_disposition_t sctp_sf_do_dupcook_d(const struct sctp_endpoint *ep, const struct sctp_association *asoc, struct sctp_chunk *chunk, sctp_cmd_seq_t *commands, struct sctp_association *new_asoc) { struct sctp_ulpevent *ev = NULL; struct sctp_chunk *repl; /* Clarification from Implementor's Guide: * D) When both local and remote tags match the endpoint should * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. * It should stop any cookie timer that may be running and send * a COOKIE ACK. */ /* Don't accidentally move back into established state. */ if (asoc->state < SCTP_STATE_ESTABLISHED) { sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_ESTABLISHED)); SCTP_INC_STATS(SctpCurrEstab); sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); /* RFC 2960 5.1 Normal Establishment of an Association * * D) IMPLEMENTATION NOTE: An implementation may choose * to send the Communication Up notification to the * SCTP user upon reception of a valid COOKIE * ECHO chunk. */ ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, new_asoc->c.sinit_num_ostreams, new_asoc->c.sinit_max_instreams, GFP_ATOMIC); if (!ev) goto nomem; sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); } sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); repl = sctp_make_cookie_ack(new_asoc, chunk); if (!repl) goto nomem; sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); sctp_add_cmd_sf(commands, SCTP_CMD_TRANSMIT, SCTP_NULL()); return SCTP_DISPOSITION_CONSUME; nomem: if (ev) sctp_ulpevent_free(ev); return SCTP_DISPOSITION_NOMEM; } /* * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying * chunk was retransmitted and then delayed in the network. * * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists * * Verification Tag: None. Do cookie validation. * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_do_5_2_4_dupcook(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { sctp_disposition_t retval; struct sctp_chunk *chunk = arg; struct sctp_association *new_asoc; int error = 0; char action; struct sctp_chunk *err_chk_p; /* "Decode" the chunk. We have no optional parameters so we * are in good shape. */ chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; skb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t)); /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie * of a duplicate COOKIE ECHO match the Verification Tags of the * current association, consider the State Cookie valid even if * the lifespan is exceeded. */ new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, &err_chk_p); /* FIXME: * If the re-build failed, what is the proper error path * from here? * * [We should abort the association. --piggy] */ if (!new_asoc) { /* FIXME: Several errors are possible. A bad cookie should * be silently discarded, but think about logging it too. */ switch (error) { case -SCTP_IERROR_NOMEM: goto nomem; case -SCTP_IERROR_STALE_COOKIE: sctp_send_stale_cookie_err(ep, asoc, chunk, commands, err_chk_p); return sctp_sf_pdiscard(ep, asoc, type, arg, commands); case -SCTP_IERROR_BAD_SIG: default: return sctp_sf_pdiscard(ep, asoc, type, arg, commands); }; } /* Compare the tie_tag in cookie with the verification tag of * current association. */ action = sctp_tietags_compare(new_asoc, asoc); switch (action) { case 'A': /* Association restart. */ retval = sctp_sf_do_dupcook_a(ep, asoc, chunk, commands, new_asoc); break; case 'B': /* Collision case B. */ retval = sctp_sf_do_dupcook_b(ep, asoc, chunk, commands, new_asoc); break; case 'C': /* Collision case C. */ retval = sctp_sf_do_dupcook_c(ep, asoc, chunk, commands, new_asoc); break; case 'D': /* Collision case D. */ retval = sctp_sf_do_dupcook_d(ep, asoc, chunk, commands, new_asoc); break; default: /* Discard packet for all others. */ retval = sctp_sf_pdiscard(ep, asoc, type, arg, commands); break; }; /* Delete the tempory new association. */ sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); return retval; nomem: return SCTP_DISPOSITION_NOMEM; } /* * Process an ABORT. (SHUTDOWN-PENDING state) * * See sctp_sf_do_9_1_abort(). */ sctp_disposition_t sctp_sf_shutdown_pending_abort( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; if (!sctp_vtag_verify_either(chunk, asoc)) return sctp_sf_pdiscard(ep, asoc, type, arg, commands); /* Stop the T5-shutdown guard timer. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); return sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); } /* * Process an ABORT. (SHUTDOWN-SENT state) * * See sctp_sf_do_9_1_abort(). */ sctp_disposition_t sctp_sf_shutdown_sent_abort(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; if (!sctp_vtag_verify_either(chunk, asoc)) return sctp_sf_pdiscard(ep, asoc, type, arg, commands); /* Stop the T2-shutdown timer. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); /* Stop the T5-shutdown guard timer. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); return sctp_sf_do_9_1_abort(ep, asoc, type, arg, commands); } /* * Process an ABORT. (SHUTDOWN-ACK-SENT state) * * See sctp_sf_do_9_1_abort(). */ sctp_disposition_t sctp_sf_shutdown_ack_sent_abort( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { /* The same T2 timer, so we should be able to use * common function with the SHUTDOWN-SENT state. */ return sctp_sf_shutdown_sent_abort(ep, asoc, type, arg, commands); } /* * Handle an Error received in COOKIE_ECHOED state. * * Only handle the error type of stale COOKIE Error, the other errors will * be ignored. * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_cookie_echoed_err(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; sctp_errhdr_t *err; /* Process the error here */ /* FUTURE FIXME: When PR-SCTP related and other optional * parms are emitted, this will have to change to handle multiple * errors. */ sctp_walk_errors(err, chunk->chunk_hdr) { if (SCTP_ERROR_STALE_COOKIE == err->cause) return sctp_sf_do_5_2_6_stale(ep, asoc, type, arg, commands); } return sctp_sf_pdiscard(ep, asoc, type, arg, commands); } /* * Handle a Stale COOKIE Error * * Section: 5.2.6 Handle Stale COOKIE Error * If the association is in the COOKIE-ECHOED state, the endpoint may elect * one of the following three alternatives. * ... * 3) Send a new INIT chunk to the endpoint, adding a Cookie * Preservative parameter requesting an extension to the lifetime of * the State Cookie. When calculating the time extension, an * implementation SHOULD use the RTT information measured based on the * previous COOKIE ECHO / ERROR exchange, and should add no more * than 1 second beyond the measured RTT, due to long State Cookie * lifetimes making the endpoint more subject to a replay attack. * * Verification Tag: Not explicit, but safe to ignore. * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_do_5_2_6_stale(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; time_t stale; sctp_cookie_preserve_param_t bht; sctp_errhdr_t *err; struct list_head *pos; struct sctp_transport *t; struct sctp_chunk *reply; struct sctp_bind_addr *bp; int attempts; attempts = asoc->counters[SCTP_COUNTER_INIT_ERROR] + 1; if (attempts >= asoc->max_init_attempts) { sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, SCTP_U32(SCTP_ERROR_STALE_COOKIE)); return SCTP_DISPOSITION_DELETE_TCB; } err = (sctp_errhdr_t *)(chunk->skb->data); /* When calculating the time extension, an implementation * SHOULD use the RTT information measured based on the * previous COOKIE ECHO / ERROR exchange, and should add no * more than 1 second beyond the measured RTT, due to long * State Cookie lifetimes making the endpoint more subject to * a replay attack. * Measure of Staleness's unit is usec. (1/1000000 sec) * Suggested Cookie Life-span Increment's unit is msec. * (1/1000 sec) * In general, if you use the suggested cookie life, the value * found in the field of measure of staleness should be doubled * to give ample time to retransmit the new cookie and thus * yield a higher probability of success on the reattempt. */ stale = ntohl(*(suseconds_t *)((u8 *)err + sizeof(sctp_errhdr_t))); stale = (stale * 2) / 1000; bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; bht.param_hdr.length = htons(sizeof(bht)); bht.lifespan_increment = htonl(stale); /* Build that new INIT chunk. */ bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); if (!reply) goto nomem; sctp_addto_chunk(reply, sizeof(bht), &bht); /* Cast away the const modifier, as we want to just * rerun it through as a sideffect. */ sctp_add_cmd_sf(commands, SCTP_CMD_COUNTER_INC, SCTP_COUNTER(SCTP_COUNTER_INIT_ERROR)); /* If we've sent any data bundled with COOKIE-ECHO we need to * resend. */ list_for_each(pos, &asoc->peer.transport_addr_list) { t = list_entry(pos, struct sctp_transport, transports); sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(t)); } sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); return SCTP_DISPOSITION_CONSUME; nomem: return SCTP_DISPOSITION_NOMEM; } /* * Process an ABORT. * * Section: 9.1 * After checking the Verification Tag, the receiving endpoint shall * remove the association from its record, and shall report the * termination to its upper layer. * * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules * B) Rules for packet carrying ABORT: * * - The endpoint shall always fill in the Verification Tag field of the * outbound packet with the destination endpoint's tag value if it * is known. * * - If the ABORT is sent in response to an OOTB packet, the endpoint * MUST follow the procedure described in Section 8.4. * * - The receiver MUST accept the packet if the Verification Tag * matches either its own tag, OR the tag of its peer. Otherwise, the * receiver MUST silently discard the packet and take no further * action. * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_do_9_1_abort(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; unsigned len; __u16 error = SCTP_ERROR_NO_ERROR; if (!sctp_vtag_verify_either(chunk, asoc)) return sctp_sf_pdiscard(ep, asoc, type, arg, commands); /* Check that chunk header looks valid. */ len = ntohs(chunk->chunk_hdr->length); if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) error = ((sctp_errhdr_t *)chunk->skb->data)->cause; /* ASSOC_FAILED will DELETE_TCB. */ sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_U32(error)); SCTP_INC_STATS(SctpAborteds); SCTP_DEC_STATS(SctpCurrEstab); return SCTP_DISPOSITION_ABORT; } /* * Process an ABORT. (COOKIE-WAIT state) * * See sctp_sf_do_9_1_abort() above. */ sctp_disposition_t sctp_sf_cookie_wait_abort(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; unsigned len; __u16 error = SCTP_ERROR_NO_ERROR; if (!sctp_vtag_verify_either(chunk, asoc)) return sctp_sf_pdiscard(ep, asoc, type, arg, commands); sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_CLOSED)); SCTP_INC_STATS(SctpAborteds); sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); /* Check that chunk header looks valid. */ len = ntohs(chunk->chunk_hdr->length); if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) error = ((sctp_errhdr_t *)chunk->skb->data)->cause; /* CMD_INIT_FAILED will DELETE_TCB. */ sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, SCTP_U32(error)); return SCTP_DISPOSITION_ABORT; } /* * Process an ABORT. (COOKIE-ECHOED state) * * See sctp_sf_do_9_1_abort() above. */ sctp_disposition_t sctp_sf_cookie_echoed_abort(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { /* There is a single T1 timer, so we should be able to use * common function with the COOKIE-WAIT state. */ return sctp_sf_cookie_wait_abort(ep, asoc, type, arg, commands); } /* * sctp_sf_do_9_2_shut * * Section: 9.2 * Upon the reception of the SHUTDOWN, the peer endpoint shall * - enter the SHUTDOWN-RECEIVED state, * * - stop accepting new data from its SCTP user * * - verify, by checking the Cumulative TSN Ack field of the chunk, * that all its outstanding DATA chunks have been received by the * SHUTDOWN sender. * * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT * send a SHUTDOWN in response to a ULP request. And should discard * subsequent SHUTDOWN chunks. * * If there are still outstanding DATA chunks left, the SHUTDOWN * receiver shall continue to follow normal data transmission * procedures defined in Section 6 until all outstanding DATA chunks * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept * new data from its SCTP user. * * Verification Tag: 8.5 Verification Tag [Normal verification] * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_do_9_2_shutdown(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; sctp_shutdownhdr_t *sdh; sctp_disposition_t disposition; struct sctp_ulpevent *ev; /* Convert the elaborate header. */ sdh = (sctp_shutdownhdr_t *)chunk->skb->data; skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t)); chunk->subh.shutdown_hdr = sdh; /* 8.5 When receiving an SCTP packet, the endpoint MUST ensure * that the value in the Verification Tag field of the * received SCTP packet matches its own Tag. If the received * Verification Tag value does not match the receiver's own * tag value, the receiver shall silently discard the packet... */ if (ntohl(chunk->sctp_hdr->vtag) != asoc->c.my_vtag) return sctp_sf_pdiscard(ep, asoc, type, arg, commands); /* Upon the reception of the SHUTDOWN, the peer endpoint shall * - enter the SHUTDOWN-RECEIVED state, * - stop accepting new data from its SCTP user * * [This is implicit in the new state.] */ sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); disposition = SCTP_DISPOSITION_CONSUME; if (sctp_outq_is_empty(&asoc->outqueue)) { disposition = sctp_sf_do_9_2_shutdown_ack(ep, asoc, type, arg, commands); } if (SCTP_DISPOSITION_NOMEM == disposition) goto out; /* - verify, by checking the Cumulative TSN Ack field of the * chunk, that all its outstanding DATA chunks have been * received by the SHUTDOWN sender. */ sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, SCTP_U32(chunk->subh.shutdown_hdr->cum_tsn_ack)); /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT * When a peer sends a SHUTDOWN, SCTP delivers this notification to * inform the application that it should cease sending data. */ ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); if (!ev) { disposition = SCTP_DISPOSITION_NOMEM; goto out; } sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); out: return disposition; } /* RFC 2960 9.2 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination * transport addresses (either in the IP addresses or in the INIT chunk) * that belong to this association, it should discard the INIT chunk and * retransmit the SHUTDOWN ACK chunk. */ sctp_disposition_t sctp_sf_do_9_2_reshutack(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = (struct sctp_chunk *) arg; struct sctp_chunk *reply; reply = sctp_make_shutdown_ack(asoc, chunk); if (NULL == reply) goto nomem; /* Set the transport for the SHUTDOWN ACK chunk and the timeout for * the T2-SHUTDOWN timer. */ sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); /* and restart the T2-shutdown timer. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); return SCTP_DISPOSITION_CONSUME; nomem: return SCTP_DISPOSITION_NOMEM; } /* * sctp_sf_do_ecn_cwr * * Section: Appendix A: Explicit Congestion Notification * * CWR: * * RFC 2481 details a specific bit for a sender to send in the header of * its next outbound TCP segment to indicate to its peer that it has * reduced its congestion window. This is termed the CWR bit. For * SCTP the same indication is made by including the CWR chunk. * This chunk contains one data element, i.e. the TSN number that * was sent in the ECNE chunk. This element represents the lowest * TSN number in the datagram that was originally marked with the * CE bit. * * Verification Tag: 8.5 Verification Tag [Normal verification] * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_do_ecn_cwr(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { sctp_cwrhdr_t *cwr; struct sctp_chunk *chunk = arg; /* 8.5 When receiving an SCTP packet, the endpoint MUST ensure * that the value in the Verification Tag field of the * received SCTP packet matches its own Tag. If the received * Verification Tag value does not match the receiver's own * tag value, the receiver shall silently discard the packet... */ if (ntohl(chunk->sctp_hdr->vtag) != asoc->c.my_vtag) return sctp_sf_pdiscard(ep, asoc, type, arg, commands); cwr = (sctp_cwrhdr_t *) chunk->skb->data; skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t)); cwr->lowest_tsn = ntohl(cwr->lowest_tsn); /* Does this CWR ack the last sent congestion notification? */ if (TSN_lte(asoc->last_ecne_tsn, cwr->lowest_tsn)) { /* Stop sending ECNE. */ sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CWR, SCTP_U32(cwr->lowest_tsn)); } return SCTP_DISPOSITION_CONSUME; } /* * sctp_sf_do_ecne * * Section: Appendix A: Explicit Congestion Notification * * ECN-Echo * * RFC 2481 details a specific bit for a receiver to send back in its * TCP acknowledgements to notify the sender of the Congestion * Experienced (CE) bit having arrived from the network. For SCTP this * same indication is made by including the ECNE chunk. This chunk * contains one data element, i.e. the lowest TSN associated with the IP * datagram marked with the CE bit..... * * Verification Tag: 8.5 Verification Tag [Normal verification] * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_do_ecne(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { sctp_ecnehdr_t *ecne; struct sctp_chunk *chunk = arg; /* 8.5 When receiving an SCTP packet, the endpoint MUST ensure * that the value in the Verification Tag field of the * received SCTP packet matches its own Tag. If the received * Verification Tag value does not match the receiver's own * tag value, the receiver shall silently discard the packet... */ if (ntohl(chunk->sctp_hdr->vtag) != asoc->c.my_vtag) return sctp_sf_pdiscard(ep, asoc, type, arg, commands); ecne = (sctp_ecnehdr_t *) chunk->skb->data; skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t)); /* If this is a newer ECNE than the last CWR packet we sent out */ sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, SCTP_U32(ntohl(ecne->lowest_tsn))); return SCTP_DISPOSITION_CONSUME; } /* * Section: 6.2 Acknowledgement on Reception of DATA Chunks * * The SCTP endpoint MUST always acknowledge the reception of each valid * DATA chunk. * * The guidelines on delayed acknowledgement algorithm specified in * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an * acknowledgement SHOULD be generated for at least every second packet * (not every second DATA chunk) received, and SHOULD be generated within * 200 ms of the arrival of any unacknowledged DATA chunk. In some * situations it may be beneficial for an SCTP transmitter to be more * conservative than the algorithms detailed in this document allow. * However, an SCTP transmitter MUST NOT be more aggressive than the * following algorithms allow. * * A SCTP receiver MUST NOT generate more than one SACK for every * incoming packet, other than to update the offered window as the * receiving application consumes new data. * * Verification Tag: 8.5 Verification Tag [Normal verification] * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_eat_data_6_2(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; sctp_datahdr_t *data_hdr; struct sctp_chunk *err; size_t datalen; sctp_verb_t deliver; int tmp; __u32 tsn; /* RFC 2960 8.5 Verification Tag * * When receiving an SCTP packet, the endpoint MUST ensure * that the value in the Verification Tag field of the * received SCTP packet matches its own Tag. */ if (ntohl(chunk->sctp_hdr->vtag) != asoc->c.my_vtag) { sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, SCTP_NULL()); return sctp_sf_pdiscard(ep, asoc, type, arg, commands); } data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data; skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); tsn = ntohl(data_hdr->tsn); SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn); /* ASSERT: Now skb->data is really the user data. */ /* Process ECN based congestion. * * Since the chunk structure is reused for all chunks within * a packet, we use ecn_ce_done to track if we've already * done CE processing for this packet. * * We need to do ECN processing even if we plan to discard the * chunk later. */ if (!chunk->ecn_ce_done) { struct sctp_af *af; chunk->ecn_ce_done = 1; af = sctp_get_af_specific( ipver2af(chunk->skb->nh.iph->version)); if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { /* Do real work as sideffect. */ sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, SCTP_U32(tsn)); } } tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); if (tmp < 0) { /* The TSN is too high--silently discard the chunk and * count on it getting retransmitted later. */ goto discard_noforce; } else if (tmp > 0) { /* This is a duplicate. Record it. */ sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); goto discard_force; } /* This is a new TSN. */ /* Discard if there is no room in the receive window. * Actually, allow a little bit of overflow (up to a MTU). */ datalen = ntohs(chunk->chunk_hdr->length); datalen -= sizeof(sctp_data_chunk_t); deliver = SCTP_CMD_CHUNK_ULP; /* Think about partial delivery. */ if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { /* Even if we don't accept this chunk there is * memory pressure. */ sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); } /* Spill over rwnd a little bit. Note: While allowed, this spill over * seems a bit troublesome in that frag_point varies based on * PMTU. In cases, such as loopback, this might be a rather * large spill over. */ if (!asoc->rwnd || asoc->rwnd_over || (datalen > asoc->rwnd + asoc->frag_point)) { /* If this is the next TSN, consider reneging to make * room. Note: Playing nice with a confused sender. A * malicious sender can still eat up all our buffer * space and in the future we may want to detect and * do more drastic reneging. */ if (sctp_tsnmap_has_gap(&asoc->peer.tsn_map) && (sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + 1) == tsn) { SCTP_DEBUG_PRINTK("Reneging for tsn:%u\n", tsn); deliver = SCTP_CMD_RENEGE; } else { SCTP_DEBUG_PRINTK("Discard tsn: %u len: %Zd, " "rwnd: %d\n", tsn, datalen, asoc->rwnd); goto discard_force; } } /* * Section 3.3.10.9 No User Data (9) * * Cause of error * --------------- * No User Data: This error cause is returned to the originator of a * DATA chunk if a received DATA chunk has no user data. */ if (unlikely(0 == datalen)) { err = sctp_make_abort_no_data(asoc, chunk, tsn); if (err) { sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(err)); } /* We are going to ABORT, so we might as well stop * processing the rest of the chunks in the packet. */ sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_U32(SCTP_ERROR_NO_DATA)); SCTP_INC_STATS(SctpAborteds); SCTP_DEC_STATS(SctpCurrEstab); return SCTP_DISPOSITION_CONSUME; } /* If definately accepting the DATA chunk, record its TSN, otherwise * wait for renege processing. */ if (SCTP_CMD_CHUNK_ULP == deliver) sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); /* Note: Some chunks may get overcounted (if we drop) or overcounted * if we renege and the chunk arrives again. */ if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) SCTP_INC_STATS(SctpInUnorderChunks); else SCTP_INC_STATS(SctpInOrderChunks); /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number * * If an endpoint receive a DATA chunk with an invalid stream * identifier, it shall acknowledge the reception of the DATA chunk * following the normal procedure, immediately send an ERROR chunk * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) * and discard the DATA chunk. */ if (ntohs(data_hdr->stream) >= asoc->c.sinit_max_instreams) { err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, &data_hdr->stream, sizeof(data_hdr->stream)); if (err) sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(err)); goto discard_noforce; } /* Send the data up to the user. Note: Schedule the * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK * chunk needs the updated rwnd. */ sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); if (asoc->autoclose) { sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); } /* If this is the last chunk in a packet, we need to count it * toward sack generation. Note that we need to SACK every * OTHER packet containing data chunks, EVEN IF WE DISCARD * THEM. We elect to NOT generate SACK's if the chunk fails * the verification tag test. * * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks * * The SCTP endpoint MUST always acknowledge the reception of * each valid DATA chunk. * * The guidelines on delayed acknowledgement algorithm * specified in Section 4.2 of [RFC2581] SHOULD be followed. * Specifically, an acknowledgement SHOULD be generated for at * least every second packet (not every second DATA chunk) * received, and SHOULD be generated within 200 ms of the * arrival of any unacknowledged DATA chunk. In some * situations it may be beneficial for an SCTP transmitter to * be more conservative than the algorithms detailed in this * document allow. However, an SCTP transmitter MUST NOT be * more aggressive than the following algorithms allow. */ if (chunk->end_of_packet) { sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); /* Start the SACK timer. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); } return SCTP_DISPOSITION_CONSUME; discard_force: /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks * * When a packet arrives with duplicate DATA chunk(s) and with * no new DATA chunk(s), the endpoint MUST immediately send a * SACK with no delay. If a packet arrives with duplicate * DATA chunk(s) bundled with new DATA chunks, the endpoint * MAY immediately send a SACK. Normally receipt of duplicate * DATA chunks will occur when the original SACK chunk was lost * and the peer's RTO has expired. The duplicate TSN number(s) * SHOULD be reported in the SACK as duplicate. */ /* In our case, we split the MAY SACK advice up whether or not * the last chunk is a duplicate.' */ if (chunk->end_of_packet) sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); return SCTP_DISPOSITION_DISCARD; discard_noforce: if (chunk->end_of_packet) { sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); /* Start the SACK timer. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); } return SCTP_DISPOSITION_DISCARD; } /* * sctp_sf_eat_data_fast_4_4 * * Section: 4 (4) * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received * DATA chunks without delay. * * Verification Tag: 8.5 Verification Tag [Normal verification] * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_eat_data_fast_4_4(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; sctp_datahdr_t *data_hdr; struct sctp_chunk *err; size_t datalen; int tmp; __u32 tsn; /* RFC 2960 8.5 Verification Tag * * When receiving an SCTP packet, the endpoint MUST ensure * that the value in the Verification Tag field of the * received SCTP packet matches its own Tag. */ if (ntohl(chunk->sctp_hdr->vtag) != asoc->c.my_vtag) { sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, SCTP_NULL()); return sctp_sf_pdiscard(ep, asoc, type, arg, commands); } data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *) chunk->skb->data; skb_pull(chunk->skb, sizeof(sctp_datahdr_t)); tsn = ntohl(data_hdr->tsn); SCTP_DEBUG_PRINTK("eat_data: TSN 0x%x.\n", tsn); /* ASSERT: Now skb->data is really the user data. */ /* Process ECN based congestion. * * Since the chunk structure is reused for all chunks within * a packet, we use ecn_ce_done to track if we've already * done CE processing for this packet. * * We need to do ECN processing even if we plan to discard the * chunk later. */ if (!chunk->ecn_ce_done) { struct sctp_af *af; chunk->ecn_ce_done = 1; af = sctp_get_af_specific( ipver2af(chunk->skb->nh.iph->version)); if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) { /* Do real work as sideffect. */ sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, SCTP_U32(tsn)); } } tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); if (tmp < 0) { /* The TSN is too high--silently discard the chunk and * count on it getting retransmitted later. */ goto gen_shutdown; } else if (tmp > 0) { /* This is a duplicate. Record it. */ sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); goto gen_shutdown; } /* This is a new TSN. */ datalen = ntohs(chunk->chunk_hdr->length); datalen -= sizeof(sctp_data_chunk_t); /* * Section 3.3.10.9 No User Data (9) * * Cause of error * --------------- * No User Data: This error cause is returned to the originator of a * DATA chunk if a received DATA chunk has no user data. */ if (unlikely(0 == datalen)) { err = sctp_make_abort_no_data(asoc, chunk, tsn); if (err) { sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(err)); } /* We are going to ABORT, so we might as well stop * processing the rest of the chunks in the packet. */ sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_U32(SCTP_ERROR_NO_DATA)); SCTP_INC_STATS(SctpAborteds); SCTP_DEC_STATS(SctpCurrEstab); return SCTP_DISPOSITION_CONSUME; } /* We are accepting this DATA chunk. */ /* Record the fact that we have received this TSN. */ sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) SCTP_INC_STATS(SctpInUnorderChunks); else SCTP_INC_STATS(SctpInOrderChunks); /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number * * If an endpoint receive a DATA chunk with an invalid stream * identifier, it shall acknowledge the reception of the DATA chunk * following the normal procedure, immediately send an ERROR chunk * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) * and discard the DATA chunk. */ if (ntohs(data_hdr->stream) >= asoc->c.sinit_max_instreams) { err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, &data_hdr->stream, sizeof(data_hdr->stream)); if (err) { sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(err)); } } /* Go a head and force a SACK, since we are shutting down. */ gen_shutdown: /* Implementor's Guide. * * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately * respond to each received packet containing one or more DATA chunk(s) * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer */ if (chunk->end_of_packet) { /* We must delay the chunk creation since the cumulative * TSN has not been updated yet. */ sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); } return SCTP_DISPOSITION_CONSUME; } /* * Section: 6.2 Processing a Received SACK * D) Any time a SACK arrives, the endpoint performs the following: * * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, * then drop the SACK. Since Cumulative TSN Ack is monotonically * increasing, a SACK whose Cumulative TSN Ack is less than the * Cumulative TSN Ack Point indicates an out-of-order SACK. * * ii) Set rwnd equal to the newly received a_rwnd minus the number * of bytes still outstanding after processing the Cumulative TSN Ack * and the Gap Ack Blocks. * * iii) If the SACK is missing a TSN that was previously * acknowledged via a Gap Ack Block (e.g., the data receiver * reneged on the data), then mark the corresponding DATA chunk * as available for retransmit: Mark it as missing for fast * retransmit as described in Section 7.2.4 and if no retransmit * timer is running for the destination address to which the DATA * chunk was originally transmitted, then T3-rtx is started for * that destination address. * * Verification Tag: 8.5 Verification Tag [Normal verification] * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_eat_sack_6_2(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; sctp_sackhdr_t *sackh; __u32 ctsn; /* 8.5 When receiving an SCTP packet, the endpoint MUST ensure * that the value in the Verification Tag field of the * received SCTP packet matches its own Tag. ... */ if (ntohl(chunk->sctp_hdr->vtag) != asoc->c.my_vtag) return sctp_sf_pdiscard(ep, asoc, type, arg, commands); /* Pull the SACK chunk from the data buffer */ sackh = sctp_sm_pull_sack(chunk); /* Was this a bogus SACK? */ if (!sackh) return sctp_sf_pdiscard(ep, asoc, type, arg, commands); chunk->subh.sack_hdr = sackh; ctsn = ntohl(sackh->cum_tsn_ack); /* i) If Cumulative TSN Ack is less than the Cumulative TSN * Ack Point, then drop the SACK. Since Cumulative TSN * Ack is monotonically increasing, a SACK whose * Cumulative TSN Ack is less than the Cumulative TSN Ack * Point indicates an out-of-order SACK. */ if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { SCTP_DEBUG_PRINTK("ctsn %x\n", ctsn); SCTP_DEBUG_PRINTK("ctsn_ack_point %x\n", asoc->ctsn_ack_point); return SCTP_DISPOSITION_DISCARD; } /* Return this SACK for further processing. */ sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_SACKH(sackh)); /* Note: We do the rest of the work on the PROCESS_SACK * sideeffect. */ return SCTP_DISPOSITION_CONSUME; } /* * Generate an ABORT in response to a packet. * * Section: 8.4 Handle "Out of the blue" Packets * * 8) The receiver should respond to the sender of the OOTB packet * with an ABORT. When sending the ABORT, the receiver of the * OOTB packet MUST fill in the Verification Tag field of the * outbound packet with the value found in the Verification Tag * field of the OOTB packet and set the T-bit in the Chunk Flags * to indicate that no TCB was found. After sending this ABORT, * the receiver of the OOTB packet shall discard the OOTB packet * and take no further action. * * Verification Tag: * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_tabort_8_4_8(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_packet *packet = NULL; struct sctp_chunk *chunk = arg; struct sctp_chunk *abort; packet = sctp_ootb_pkt_new(asoc, chunk); if (packet) { /* Make an ABORT. The T bit will be set if the asoc * is NULL. */ abort = sctp_make_abort(asoc, chunk, 0); if (!abort) { sctp_ootb_pkt_free(packet); return SCTP_DISPOSITION_NOMEM; } /* Set the skb to the belonging sock for accounting. */ abort->skb->sk = ep->base.sk; sctp_packet_append_chunk(packet, abort); sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet)); SCTP_INC_STATS(SctpOutCtrlChunks); return SCTP_DISPOSITION_CONSUME; } return SCTP_DISPOSITION_NOMEM; } /* * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR * event as ULP notification for each cause included in the chunk. * * API 5.3.1.3 - SCTP_REMOTE_ERROR * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_operr_notify(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; struct sctp_ulpevent *ev; while (chunk->chunk_end > chunk->skb->data) { ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0, GFP_ATOMIC); if (!ev) goto nomem; if (!sctp_add_cmd(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev))) { sctp_ulpevent_free(ev); goto nomem; } sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, SCTP_CHUNK(chunk)); } return SCTP_DISPOSITION_CONSUME; nomem: return SCTP_DISPOSITION_NOMEM; } /* * Process an inbound SHUTDOWN ACK. * * From Section 9.2: * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its * peer, and remove all record of the association. * * The return value is the disposition. */ sctp_disposition_t sctp_sf_do_9_2_final(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; struct sctp_chunk *reply; struct sctp_ulpevent *ev; /* 10.2 H) SHUTDOWN COMPLETE notification * * When SCTP completes the shutdown procedures (section 9.2) this * notification is passed to the upper layer. */ ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 0, 0, 0, GFP_ATOMIC); if (!ev) goto nomem; sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall * stop the T2-shutdown timer, */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ reply = sctp_make_shutdown_complete(asoc, chunk); if (!reply) goto nomem; sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_CLOSED)); SCTP_INC_STATS(SctpShutdowns); SCTP_DEC_STATS(SctpCurrEstab); sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); /* ...and remove all record of the association. */ sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); return SCTP_DISPOSITION_DELETE_TCB; nomem: return SCTP_DISPOSITION_NOMEM; } /* * RFC 2960, 8.4 - Handle "Out of the blue" Packets * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB * packet must fill in the Verification Tag field of the outbound * packet with the Verification Tag received in the SHUTDOWN ACK and * set the T-bit in the Chunk Flags to indicate that no TCB was * found. Otherwise, * * 8) The receiver should respond to the sender of the OOTB packet with * an ABORT. When sending the ABORT, the receiver of the OOTB packet * MUST fill in the Verification Tag field of the outbound packet * with the value found in the Verification Tag field of the OOTB * packet and set the T-bit in the Chunk Flags to indicate that no * TCB was found. After sending this ABORT, the receiver of the OOTB * packet shall discard the OOTB packet and take no further action. */ sctp_disposition_t sctp_sf_ootb(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; struct sk_buff *skb = chunk->skb; sctp_chunkhdr_t *ch; __u8 *ch_end; int ootb_shut_ack = 0; SCTP_INC_STATS(SctpOutOfBlues); ch = (sctp_chunkhdr_t *) chunk->chunk_hdr; do { ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); if (SCTP_CID_SHUTDOWN_ACK == ch->type) ootb_shut_ack = 1; ch = (sctp_chunkhdr_t *) ch_end; } while (ch_end < skb->tail); if (ootb_shut_ack) sctp_sf_shut_8_4_5(ep, asoc, type, arg, commands); else sctp_sf_tabort_8_4_8(ep, asoc, type, arg, commands); return sctp_sf_pdiscard(ep, asoc, type, arg, commands); } /* * Handle an "Out of the blue" SHUTDOWN ACK. * * Section: 8.4 5) * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB packet * must fill in the Verification Tag field of the outbound packet with * the Verification Tag received in the SHUTDOWN ACK and set the * T-bit in the Chunk Flags to indicate that no TCB was found. * * Inputs * (endpoint, asoc, type, arg, commands) * * Outputs * (sctp_disposition_t) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_shut_8_4_5(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_packet *packet = NULL; struct sctp_chunk *chunk = arg; struct sctp_chunk *shut; packet = sctp_ootb_pkt_new(asoc, chunk); if (packet) { /* Make an SHUTDOWN_COMPLETE. * The T bit will be set if the asoc is NULL. */ shut = sctp_make_shutdown_complete(asoc, chunk); if (!shut) { sctp_ootb_pkt_free(packet); return SCTP_DISPOSITION_NOMEM; } /* Set the skb to the belonging sock for accounting. */ shut->skb->sk = ep->base.sk; sctp_packet_append_chunk(packet, shut); sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet)); SCTP_INC_STATS(SctpOutCtrlChunks); return SCTP_DISPOSITION_CONSUME; } return SCTP_DISPOSITION_NOMEM; } /* * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. * * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the * procedures in section 8.4 SHOULD be followed, in other words it * should be treated as an Out Of The Blue packet. * [This means that we do NOT check the Verification Tag on these * chunks. --piggy ] * */ sctp_disposition_t sctp_sf_do_8_5_1_E_sa(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { /* Although we do have an association in this case, it corresponds * to a restarted association. So the packet is treated as an OOTB * packet and the state function that handles OOTB SHUTDOWN_ACK is * called with a NULL association. */ return sctp_sf_shut_8_4_5(ep, NULL, type, arg, commands); } /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ sctp_disposition_t sctp_sf_do_asconf(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; struct sctp_chunk *asconf_ack = NULL; sctp_addiphdr_t *hdr; __u32 serial; hdr = (sctp_addiphdr_t *)chunk->skb->data; serial = ntohl(hdr->serial); /* ADDIP 4.2 C1) Compare the value of the serial number to the value * the endpoint stored in a new association variable * 'Peer-Serial-Number'. */ if (serial == asoc->peer.addip_serial + 1) { /* ADDIP 4.2 C2) If the value found in the serial number is * equal to the ('Peer-Serial-Number' + 1), the endpoint MUST * do V1-V5. */ asconf_ack = sctp_process_asconf((struct sctp_association *) asoc, chunk); if (!asconf_ack) return SCTP_DISPOSITION_NOMEM; } else if (serial == asoc->peer.addip_serial) { /* ADDIP 4.2 C3) If the value found in the serial number is * equal to the value stored in the 'Peer-Serial-Number' * IMPLEMENTATION NOTE: As an optimization a receiver may wish * to save the last ASCONF-ACK for some predetermined period of * time and instead of re-processing the ASCONF (with the same * serial number) it may just re-transmit the ASCONF-ACK. */ if (asoc->addip_last_asconf_ack) asconf_ack = asoc->addip_last_asconf_ack; else return SCTP_DISPOSITION_DISCARD; } else { /* ADDIP 4.2 C4) Otherwise, the ASCONF Chunk is discarded since * it must be either a stale packet or from an attacker. */ return SCTP_DISPOSITION_DISCARD; } /* ADDIP 4.2 C5) In both cases C2 and C3 the ASCONF-ACK MUST be sent * back to the source address contained in the IP header of the ASCONF * being responded to. */ sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); return SCTP_DISPOSITION_CONSUME; } /* * ADDIP Section 4.3 General rules for address manipulation * When building TLV parameters for the ASCONF Chunk that will add or * delete IP addresses the D0 to D13 rules should be applied: */ sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *asconf_ack = arg; struct sctp_chunk *last_asconf = asoc->addip_last_asconf; struct sctp_chunk *abort; sctp_addiphdr_t *addip_hdr; __u32 sent_serial, rcvd_serial; addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data; rcvd_serial = ntohl(addip_hdr->serial); if (last_asconf) { addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr; sent_serial = ntohl(addip_hdr->serial); } else { sent_serial = asoc->addip_serial - 1; } /* D0) If an endpoint receives an ASCONF-ACK that is greater than or * equal to the next serial number to be used but no ASCONF chunk is * outstanding the endpoint MUST ABORT the association. Note that a * sequence number is greater than if it is no more than 2^^31-1 * larger than the current sequence number (using serial arithmetic). */ if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && !(asoc->addip_last_asconf)) { abort = sctp_make_abort(asoc, asconf_ack, sizeof(sctp_errhdr_t)); if (abort) { sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, NULL, 0); sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); } /* We are going to ABORT, so we might as well stop * processing the rest of the chunks in the packet. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_U32(SCTP_ERROR_ASCONF_ACK)); SCTP_INC_STATS(SctpAborteds); SCTP_DEC_STATS(SctpCurrEstab); return SCTP_DISPOSITION_ABORT; } if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); if (!sctp_process_asconf_ack((struct sctp_association *)asoc, asconf_ack)) return SCTP_DISPOSITION_CONSUME; abort = sctp_make_abort(asoc, asconf_ack, sizeof(sctp_errhdr_t)); if (abort) { sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, NULL, 0); sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); } /* We are going to ABORT, so we might as well stop * processing the rest of the chunks in the packet. */ sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET,SCTP_NULL()); sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_U32(SCTP_ERROR_ASCONF_ACK)); SCTP_INC_STATS(SctpAborteds); SCTP_DEC_STATS(SctpCurrEstab); return SCTP_DISPOSITION_ABORT; } return SCTP_DISPOSITION_DISCARD; } /* * Process an unknown chunk. * * Section: 3.2. Also, 2.1 in the implementor's guide. * * Chunk Types are encoded such that the highest-order two bits specify * the action that must be taken if the processing endpoint does not * recognize the Chunk Type. * * 00 - Stop processing this SCTP packet and discard it, do not process * any further chunks within it. * * 01 - Stop processing this SCTP packet and discard it, do not process * any further chunks within it, and report the unrecognized * chunk in an 'Unrecognized Chunk Type'. * * 10 - Skip this chunk and continue processing. * * 11 - Skip this chunk and continue processing, but report in an ERROR * Chunk using the 'Unrecognized Chunk Type' cause of error. * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_unk_chunk(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *unk_chunk = arg; struct sctp_chunk *err_chunk; sctp_chunkhdr_t *hdr; SCTP_DEBUG_PRINTK("Processing the unknown chunk id %d.\n", type.chunk); /* 8.5 When receiving an SCTP packet, the endpoint MUST ensure * that the value in the Verification Tag field of the * received SCTP packet matches its own Tag. If the received * Verification Tag value does not match the receiver's own * tag value, the receiver shall silently discard the packet. */ if (ntohl(unk_chunk->sctp_hdr->vtag) != asoc->c.my_vtag) return sctp_sf_pdiscard(ep, asoc, type, arg, commands); switch (type.chunk & SCTP_CID_ACTION_MASK) { case SCTP_CID_ACTION_DISCARD: /* Discard the packet. */ return sctp_sf_pdiscard(ep, asoc, type, arg, commands); break; case SCTP_CID_ACTION_DISCARD_ERR: /* Discard the packet. */ sctp_sf_pdiscard(ep, asoc, type, arg, commands); /* Generate an ERROR chunk as response. */ hdr = unk_chunk->chunk_hdr; err_chunk = sctp_make_op_error(asoc, unk_chunk, SCTP_ERROR_UNKNOWN_CHUNK, hdr, WORD_ROUND(ntohs(hdr->length))); if (err_chunk) { sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(err_chunk)); } return SCTP_DISPOSITION_CONSUME; break; case SCTP_CID_ACTION_SKIP: /* Skip the chunk. */ return SCTP_DISPOSITION_DISCARD; break; case SCTP_CID_ACTION_SKIP_ERR: /* Generate an ERROR chunk as response. */ hdr = unk_chunk->chunk_hdr; err_chunk = sctp_make_op_error(asoc, unk_chunk, SCTP_ERROR_UNKNOWN_CHUNK, hdr, WORD_ROUND(ntohs(hdr->length))); if (err_chunk) { sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(err_chunk)); } /* Skip the chunk. */ return SCTP_DISPOSITION_CONSUME; break; default: break; } return SCTP_DISPOSITION_DISCARD; } /* * Discard the chunk. * * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 * [Too numerous to mention...] * Verification Tag: No verification needed. * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_discard_chunk(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { SCTP_DEBUG_PRINTK("Chunk %d is discarded\n", type.chunk); return SCTP_DISPOSITION_DISCARD; } /* * Discard the whole packet. * * Section: 8.4 2) * * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST * silently discard the OOTB packet and take no further action. * Otherwise, * * Verification Tag: No verification necessary * * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_pdiscard(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); return SCTP_DISPOSITION_CONSUME; } /* * The other end is violating protocol. * * Section: Not specified * Verification Tag: Not specified * Inputs * (endpoint, asoc, chunk) * * Outputs * (asoc, reply_msg, msg_up, timers, counters) * * We simply tag the chunk as a violation. The state machine will log * the violation and continue. */ sctp_disposition_t sctp_sf_violation(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { return SCTP_DISPOSITION_VIOLATION; } /*************************************************************************** * These are the state functions for handling primitive (Section 10) events. ***************************************************************************/ /* * sctp_sf_do_prm_asoc * * Section: 10.1 ULP-to-SCTP * B) Associate * * Format: ASSOCIATE(local SCTP instance name, destination transport addr, * outbound stream count) * -> association id [,destination transport addr list] [,outbound stream * count] * * This primitive allows the upper layer to initiate an association to a * specific peer endpoint. * * The peer endpoint shall be specified by one of the transport addresses * which defines the endpoint (see Section 1.4). If the local SCTP * instance has not been initialized, the ASSOCIATE is considered an * error. * [This is not relevant for the kernel implementation since we do all * initialization at boot time. It we hadn't initialized we wouldn't * get anywhere near this code.] * * An association id, which is a local handle to the SCTP association, * will be returned on successful establishment of the association. If * SCTP is not able to open an SCTP association with the peer endpoint, * an error is returned. * [In the kernel implementation, the struct sctp_association needs to * be created BEFORE causing this primitive to run.] * * Other association parameters may be returned, including the * complete destination transport addresses of the peer as well as the * outbound stream count of the local endpoint. One of the transport * address from the returned destination addresses will be selected by * the local endpoint as default primary path for sending SCTP packets * to this peer. The returned "destination transport addr list" can * be used by the ULP to change the default primary path or to force * sending a packet to a specific transport address. [All of this * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING * function.] * * Mandatory attributes: * * o local SCTP instance name - obtained from the INITIALIZE operation. * [This is the argument asoc.] * o destination transport addr - specified as one of the transport * addresses of the peer endpoint with which the association is to be * established. * [This is asoc->peer.active_path.] * o outbound stream count - the number of outbound streams the ULP * would like to open towards this peer endpoint. * [BUG: This is not currently implemented.] * Optional attributes: * * None. * * The return value is a disposition. */ sctp_disposition_t sctp_sf_do_prm_asoc(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *repl; /* The comment below says that we enter COOKIE-WAIT AFTER * sending the INIT, but that doesn't actually work in our * implementation... */ sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); /* RFC 2960 5.1 Normal Establishment of an Association * * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" * must provide its Verification Tag (Tag_A) in the Initiate * Tag field. Tag_A SHOULD be a random number in the range of * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... */ repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); if (!repl) goto nomem; /* Cast away the const modifier, as we want to just * rerun it through as a sideffect. */ sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC((struct sctp_association *) asoc)); /* After sending the INIT, "A" starts the T1-init timer and * enters the COOKIE-WAIT state. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); return SCTP_DISPOSITION_CONSUME; nomem: return SCTP_DISPOSITION_NOMEM; } /* * Process the SEND primitive. * * Section: 10.1 ULP-to-SCTP * E) Send * * Format: SEND(association id, buffer address, byte count [,context] * [,stream id] [,life time] [,destination transport address] * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) * -> result * * This is the main method to send user data via SCTP. * * Mandatory attributes: * * o association id - local handle to the SCTP association * * o buffer address - the location where the user message to be * transmitted is stored; * * o byte count - The size of the user data in number of bytes; * * Optional attributes: * * o context - an optional 32 bit integer that will be carried in the * sending failure notification to the ULP if the transportation of * this User Message fails. * * o stream id - to indicate which stream to send the data on. If not * specified, stream 0 will be used. * * o life time - specifies the life time of the user data. The user data * will not be sent by SCTP after the life time expires. This * parameter can be used to avoid efforts to transmit stale * user messages. SCTP notifies the ULP if the data cannot be * initiated to transport (i.e. sent to the destination via SCTP's * send primitive) within the life time variable. However, the * user data will be transmitted if SCTP has attempted to transmit a * chunk before the life time expired. * * o destination transport address - specified as one of the destination * transport addresses of the peer endpoint to which this packet * should be sent. Whenever possible, SCTP should use this destination * transport address for sending the packets, instead of the current * primary path. * * o unorder flag - this flag, if present, indicates that the user * would like the data delivered in an unordered fashion to the peer * (i.e., the U flag is set to 1 on all DATA chunks carrying this * message). * * o no-bundle flag - instructs SCTP not to bundle this user data with * other outbound DATA chunks. SCTP MAY still bundle even when * this flag is present, when faced with network congestion. * * o payload protocol-id - A 32 bit unsigned integer that is to be * passed to the peer indicating the type of payload protocol data * being transmitted. This value is passed as opaque data by SCTP. * * The return value is the disposition. */ sctp_disposition_t sctp_sf_do_prm_send(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); return SCTP_DISPOSITION_CONSUME; } /* * Process the SHUTDOWN primitive. * * Section: 10.1: * C) Shutdown * * Format: SHUTDOWN(association id) * -> result * * Gracefully closes an association. Any locally queued user data * will be delivered to the peer. The association will be terminated only * after the peer acknowledges all the SCTP packets sent. A success code * will be returned on successful termination of the association. If * attempting to terminate the association results in a failure, an error * code shall be returned. * * Mandatory attributes: * * o association id - local handle to the SCTP association * * Optional attributes: * * None. * * The return value is the disposition. */ sctp_disposition_t sctp_sf_do_9_2_prm_shutdown( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { int disposition; /* From 9.2 Shutdown of an Association * Upon receipt of the SHUTDOWN primitive from its upper * layer, the endpoint enters SHUTDOWN-PENDING state and * remains there until all outstanding data has been * acknowledged by its peer. The endpoint accepts no new data * from its upper layer, but retransmits data to the far end * if necessary to fill gaps. */ sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); /* sctpimpguide-05 Section 2.12.2 * The sender of the SHUTDOWN MAY also start an overall guard timer * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); disposition = SCTP_DISPOSITION_CONSUME; if (sctp_outq_is_empty(&asoc->outqueue)) { disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, arg, commands); } return disposition; } /* * Process the ABORT primitive. * * Section: 10.1: * C) Abort * * Format: Abort(association id [, cause code]) * -> result * * Ungracefully closes an association. Any locally queued user data * will be discarded and an ABORT chunk is sent to the peer. A success code * will be returned on successful abortion of the association. If * attempting to abort the association results in a failure, an error * code shall be returned. * * Mandatory attributes: * * o association id - local handle to the SCTP association * * Optional attributes: * * o cause code - reason of the abort to be passed to the peer * * None. * * The return value is the disposition. */ sctp_disposition_t sctp_sf_do_9_1_prm_abort( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { /* From 9.1 Abort of an Association * Upon receipt of the ABORT primitive from its upper * layer, the endpoint enters CLOSED state and * discard all outstanding data has been * acknowledged by its peer. The endpoint accepts no new data * from its upper layer, but retransmits data to the far end * if necessary to fill gaps. */ struct msghdr *msg = arg; struct sctp_chunk *abort; sctp_disposition_t retval; retval = SCTP_DISPOSITION_CONSUME; /* Generate ABORT chunk to send the peer. */ abort = sctp_make_abort_user(asoc, NULL, msg); if (!abort) retval = SCTP_DISPOSITION_NOMEM; else sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); /* Even if we can't send the ABORT due to low memory delete the * TCB. This is a departure from our typical NOMEM handling. */ /* Delete the established association. */ sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_U32(SCTP_ERROR_USER_ABORT)); SCTP_INC_STATS(SctpAborteds); SCTP_DEC_STATS(SctpCurrEstab); return retval; } /* We tried an illegal operation on an association which is closed. */ sctp_disposition_t sctp_sf_error_closed(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); return SCTP_DISPOSITION_CONSUME; } /* We tried an illegal operation on an association which is shutting * down. */ sctp_disposition_t sctp_sf_error_shutdown(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-ESHUTDOWN)); return SCTP_DISPOSITION_CONSUME; } /* * sctp_cookie_wait_prm_shutdown * * Section: 4 Note: 2 * Verification Tag: * Inputs * (endpoint, asoc) * * The RFC does not explicitly address this issue, but is the route through the * state table when someone issues a shutdown while in COOKIE_WAIT state. * * Outputs * (timers) */ sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_CLOSED)); SCTP_INC_STATS(SctpShutdowns); sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); return SCTP_DISPOSITION_DELETE_TCB; } /* * sctp_cookie_echoed_prm_shutdown * * Section: 4 Note: 2 * Verification Tag: * Inputs * (endpoint, asoc) * * The RFC does not explcitly address this issue, but is the route through the * state table when someone issues a shutdown while in COOKIE_ECHOED state. * * Outputs * (timers) */ sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { /* There is a single T1 timer, so we should be able to use * common function with the COOKIE-WAIT state. */ return sctp_sf_cookie_wait_prm_shutdown(ep, asoc, type, arg, commands); } /* * sctp_sf_cookie_wait_prm_abort * * Section: 4 Note: 2 * Verification Tag: * Inputs * (endpoint, asoc) * * The RFC does not explicitly address this issue, but is the route through the * state table when someone issues an abort while in COOKIE_WAIT state. * * Outputs * (timers) */ sctp_disposition_t sctp_sf_cookie_wait_prm_abort( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct msghdr *msg = arg; struct sctp_chunk *abort; sctp_disposition_t retval; /* Stop T1-init timer */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); retval = SCTP_DISPOSITION_CONSUME; /* Generate ABORT chunk to send the peer */ abort = sctp_make_abort_user(asoc, NULL, msg); if (!abort) retval = SCTP_DISPOSITION_NOMEM; else sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_CLOSED)); SCTP_INC_STATS(SctpAborteds); /* Even if we can't send the ABORT due to low memory delete the * TCB. This is a departure from our typical NOMEM handling. */ /* Delete the established association. */ sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, SCTP_U32(SCTP_ERROR_USER_ABORT)); return retval; } /* * sctp_sf_cookie_echoed_prm_abort * * Section: 4 Note: 3 * Verification Tag: * Inputs * (endpoint, asoc) * * The RFC does not explcitly address this issue, but is the route through the * state table when someone issues an abort while in COOKIE_ECHOED state. * * Outputs * (timers) */ sctp_disposition_t sctp_sf_cookie_echoed_prm_abort( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { /* There is a single T1 timer, so we should be able to use * common function with the COOKIE-WAIT state. */ return sctp_sf_cookie_wait_prm_abort(ep, asoc, type, arg, commands); } /* * sctp_sf_shutdown_pending_prm_abort * * Inputs * (endpoint, asoc) * * The RFC does not explicitly address this issue, but is the route through the * state table when someone issues an abort while in SHUTDOWN-PENDING state. * * Outputs * (timers) */ sctp_disposition_t sctp_sf_shutdown_pending_prm_abort( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { /* Stop the T5-shutdown guard timer. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); } /* * sctp_sf_shutdown_sent_prm_abort * * Inputs * (endpoint, asoc) * * The RFC does not explicitly address this issue, but is the route through the * state table when someone issues an abort while in SHUTDOWN-SENT state. * * Outputs * (timers) */ sctp_disposition_t sctp_sf_shutdown_sent_prm_abort( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { /* Stop the T2-shutdown timer. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); /* Stop the T5-shutdown guard timer. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); return sctp_sf_do_9_1_prm_abort(ep, asoc, type, arg, commands); } /* * sctp_sf_cookie_echoed_prm_abort * * Inputs * (endpoint, asoc) * * The RFC does not explcitly address this issue, but is the route through the * state table when someone issues an abort while in COOKIE_ECHOED state. * * Outputs * (timers) */ sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { /* The same T2 timer, so we should be able to use * common function with the SHUTDOWN-SENT state. */ return sctp_sf_shutdown_sent_prm_abort(ep, asoc, type, arg, commands); } /* * Process the REQUESTHEARTBEAT primitive * * 10.1 ULP-to-SCTP * J) Request Heartbeat * * Format: REQUESTHEARTBEAT(association id, destination transport address) * * -> result * * Instructs the local endpoint to perform a HeartBeat on the specified * destination transport address of the given association. The returned * result should indicate whether the transmission of the HEARTBEAT * chunk to the destination address is successful. * * Mandatory attributes: * * o association id - local handle to the SCTP association * * o destination transport address - the transport address of the * association on which a heartbeat should be issued. */ sctp_disposition_t sctp_sf_do_prm_requestheartbeat( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { return sctp_sf_heartbeat(ep, asoc, type, (struct sctp_transport *)arg, commands); } /* * ADDIP Section 4.1 ASCONF Chunk Procedures * When an endpoint has an ASCONF signaled change to be sent to the * remote endpoint it should do A1 to A9 */ sctp_disposition_t sctp_sf_do_prm_asconf(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = arg; sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); return SCTP_DISPOSITION_CONSUME; } /* * Ignore the primitive event * * The return value is the disposition of the primitive. */ sctp_disposition_t sctp_sf_ignore_primitive( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { SCTP_DEBUG_PRINTK("Primitive type %d is ignored.\n", type.primitive); return SCTP_DISPOSITION_DISCARD; } /*************************************************************************** * These are the state functions for the OTHER events. ***************************************************************************/ /* * Start the shutdown negotiation. * * From Section 9.2: * Once all its outstanding data has been acknowledged, the endpoint * shall send a SHUTDOWN chunk to its peer including in the Cumulative * TSN Ack field the last sequential TSN it has received from the peer. * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT * state. If the timer expires, the endpoint must re-send the SHUTDOWN * with the updated last sequential TSN received from its peer. * * The return value is the disposition. */ sctp_disposition_t sctp_sf_do_9_2_start_shutdown( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *reply; /* Once all its outstanding data has been acknowledged, the * endpoint shall send a SHUTDOWN chunk to its peer including * in the Cumulative TSN Ack field the last sequential TSN it * has received from the peer. */ reply = sctp_make_shutdown(asoc, NULL); if (!reply) goto nomem; /* Set the transport for the SHUTDOWN chunk and the timeout for the * T2-shutdown timer. */ sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); /* It shall then start the T2-shutdown timer */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); if (asoc->autoclose) sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); /* and enter the SHUTDOWN-SENT state. */ sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); /* sctp-implguide 2.10 Issues with Heartbeating and failover * * HEARTBEAT ... is discontinued after sending either SHUTDOWN * or SHUTDOWN-ACK. */ sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); return SCTP_DISPOSITION_CONSUME; nomem: return SCTP_DISPOSITION_NOMEM; } /* * Generate a SHUTDOWN ACK now that everything is SACK'd. * * From Section 9.2: * * If it has no more outstanding DATA chunks, the SHUTDOWN receiver * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the * endpoint must re-send the SHUTDOWN ACK. * * The return value is the disposition. */ sctp_disposition_t sctp_sf_do_9_2_shutdown_ack( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = (struct sctp_chunk *) arg; struct sctp_chunk *reply; /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver * shall send a SHUTDOWN ACK ... */ reply = sctp_make_shutdown_ack(asoc, chunk); if (!reply) goto nomem; /* Set the transport for the SHUTDOWN ACK chunk and the timeout for * the T2-shutdown timer. */ sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); /* and start/restart a T2-shutdown timer of its own, */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); if (asoc->autoclose) sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); /* Enter the SHUTDOWN-ACK-SENT state. */ sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); /* sctp-implguide 2.10 Issues with Heartbeating and failover * * HEARTBEAT ... is discontinued after sending either SHUTDOWN * or SHUTDOWN-ACK. */ sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); return SCTP_DISPOSITION_CONSUME; nomem: return SCTP_DISPOSITION_NOMEM; } /* * Ignore the event defined as other * * The return value is the disposition of the event. */ sctp_disposition_t sctp_sf_ignore_other(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { SCTP_DEBUG_PRINTK("The event other type %d is ignored\n", type.other); return SCTP_DISPOSITION_DISCARD; } /************************************************************ * These are the state functions for handling timeout events. ************************************************************/ /* * RTX Timeout * * Section: 6.3.3 Handle T3-rtx Expiration * * Whenever the retransmission timer T3-rtx expires for a destination * address, do the following: * [See below] * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_do_6_3_3_rtx(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_transport *transport = arg; if (asoc->overall_error_count >= asoc->max_retrans) { /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_U32(SCTP_ERROR_NO_ERROR)); SCTP_INC_STATS(SctpAborteds); SCTP_DEC_STATS(SctpCurrEstab); return SCTP_DISPOSITION_DELETE_TCB; } /* E1) For the destination address for which the timer * expires, adjust its ssthresh with rules defined in Section * 7.2.3 and set the cwnd <- MTU. */ /* E2) For the destination address for which the timer * expires, set RTO <- RTO * 2 ("back off the timer"). The * maximum value discussed in rule C7 above (RTO.max) may be * used to provide an upper bound to this doubling operation. */ /* E3) Determine how many of the earliest (i.e., lowest TSN) * outstanding DATA chunks for the address for which the * T3-rtx has expired will fit into a single packet, subject * to the MTU constraint for the path corresponding to the * destination transport address to which the retransmission * is being sent (this may be different from the address for * which the timer expires [see Section 6.4]). Call this * value K. Bundle and retransmit those K DATA chunks in a * single packet to the destination endpoint. * * Note: Any DATA chunks that were sent to the address for * which the T3-rtx timer expired but did not fit in one MTU * (rule E3 above), should be marked for retransmission and * sent as soon as cwnd allows (normally when a SACK arrives). */ /* NB: Rules E4 and F1 are implicit in R1. */ sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); /* Do some failure management (Section 8.2). */ sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); return SCTP_DISPOSITION_CONSUME; } /* * Generate delayed SACK on timeout * * Section: 6.2 Acknowledgement on Reception of DATA Chunks * * The guidelines on delayed acknowledgement algorithm specified in * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an * acknowledgement SHOULD be generated for at least every second packet * (not every second DATA chunk) received, and SHOULD be generated * within 200 ms of the arrival of any unacknowledged DATA chunk. In * some situations it may be beneficial for an SCTP transmitter to be * more conservative than the algorithms detailed in this document * allow. However, an SCTP transmitter MUST NOT be more aggressive than * the following algorithms allow. */ sctp_disposition_t sctp_sf_do_6_2_sack(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); return SCTP_DISPOSITION_CONSUME; } /* * sctp_sf_t1_timer_expire * * Section: 4 Note: 2 * Verification Tag: * Inputs * (endpoint, asoc) * * RFC 2960 Section 4 Notes * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT * and re-start the T1-init timer without changing state. This MUST * be repeated up to 'Max.Init.Retransmits' times. After that, the * endpoint MUST abort the initialization process and report the * error to SCTP user. * * 3) If the T1-cookie timer expires, the endpoint MUST retransmit * COOKIE ECHO and re-start the T1-cookie timer without changing * state. This MUST be repeated up to 'Max.Init.Retransmits' times. * After that, the endpoint MUST abort the initialization process and * report the error to SCTP user. * * Outputs * (timers, events) * */ sctp_disposition_t sctp_sf_t1_timer_expire(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *repl; struct sctp_bind_addr *bp; sctp_event_timeout_t timer = (sctp_event_timeout_t) arg; int timeout; int attempts; timeout = asoc->timeouts[timer]; attempts = asoc->counters[SCTP_COUNTER_INIT_ERROR] + 1; repl = NULL; SCTP_DEBUG_PRINTK("Timer T1 expired.\n"); if (attempts < asoc->max_init_attempts) { switch (timer) { case SCTP_EVENT_TIMEOUT_T1_INIT: bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); break; case SCTP_EVENT_TIMEOUT_T1_COOKIE: repl = sctp_make_cookie_echo(asoc, NULL); break; default: BUG(); break; }; if (!repl) goto nomem; /* Issue a sideeffect to do the needed accounting. */ sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, SCTP_TO(timer)); sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); } else { sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, SCTP_U32(SCTP_ERROR_NO_ERROR)); return SCTP_DISPOSITION_DELETE_TCB; } return SCTP_DISPOSITION_CONSUME; nomem: return SCTP_DISPOSITION_NOMEM; } /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN * with the updated last sequential TSN received from its peer. * * An endpoint should limit the number of retransmissions of the * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. * If this threshold is exceeded the endpoint should destroy the TCB and * MUST report the peer endpoint unreachable to the upper layer (and * thus the association enters the CLOSED state). The reception of any * packet from its peer (i.e. as the peer sends all of its queued DATA * chunks) should clear the endpoint's retransmission count and restart * the T2-Shutdown timer, giving its peer ample opportunity to transmit * all of its queued DATA chunks that have not yet been sent. */ sctp_disposition_t sctp_sf_t2_timer_expire(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *reply = NULL; SCTP_DEBUG_PRINTK("Timer T2 expired.\n"); if (asoc->overall_error_count >= asoc->max_retrans) { /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_U32(SCTP_ERROR_NO_ERROR)); SCTP_INC_STATS(SctpAborteds); SCTP_DEC_STATS(SctpCurrEstab); return SCTP_DISPOSITION_DELETE_TCB; } switch (asoc->state) { case SCTP_STATE_SHUTDOWN_SENT: reply = sctp_make_shutdown(asoc, NULL); break; case SCTP_STATE_SHUTDOWN_ACK_SENT: reply = sctp_make_shutdown_ack(asoc, NULL); break; default: BUG(); break; }; if (!reply) goto nomem; /* Do some failure management (Section 8.2). */ sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for * the T2-shutdown timer. */ sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); /* Restart the T2-shutdown timer. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); return SCTP_DISPOSITION_CONSUME; nomem: return SCTP_DISPOSITION_NOMEM; } /* * ADDIP Section 4.1 ASCONF CHunk Procedures * If the T4 RTO timer expires the endpoint should do B1 to B5 */ sctp_disposition_t sctp_sf_t4_timer_expire( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *chunk = asoc->addip_last_asconf; struct sctp_transport *transport = chunk->transport; /* ADDIP 4.1 B1) Increment the error counters and perform path failure * detection on the appropriate destination address as defined in * RFC2960 [5] section 8.1 and 8.2. */ sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); /* Reconfig T4 timer and transport. */ sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); /* ADDIP 4.1 B2) Increment the association error counters and perform * endpoint failure detection on the association as defined in * RFC2960 [5] section 8.1 and 8.2. * association error counter is incremented in SCTP_CMD_STRIKE. */ if (asoc->overall_error_count >= asoc->max_retrans) { sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_U32(SCTP_ERROR_NO_ERROR)); SCTP_INC_STATS(SctpAborteds); SCTP_INC_STATS(SctpCurrEstab); return SCTP_DISPOSITION_ABORT; } /* ADDIP 4.1 B3) Back-off the destination address RTO value to which * the ASCONF chunk was sent by doubling the RTO timer value. * This is done in SCTP_CMD_STRIKE. */ /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible * choose an alternate destination address (please refer to RFC2960 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this * chunk, it MUST be the same (including its serial number) as the last * ASCONF sent. */ sctp_chunk_hold(asoc->addip_last_asconf); sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asoc->addip_last_asconf)); /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different * destination is selected, then the RTO used will be that of the new * destination address. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); return SCTP_DISPOSITION_CONSUME; } /* sctpimpguide-05 Section 2.12.2 * The sender of the SHUTDOWN MAY also start an overall guard timer * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. * At the expiration of this timer the sender SHOULD abort the association * by sending an ABORT chunk. */ sctp_disposition_t sctp_sf_t5_timer_expire(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { struct sctp_chunk *reply = NULL; SCTP_DEBUG_PRINTK("Timer T5 expired.\n"); reply = sctp_make_abort(asoc, NULL, 0); if (!reply) goto nomem; sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_U32(SCTP_ERROR_NO_ERROR)); return SCTP_DISPOSITION_DELETE_TCB; nomem: return SCTP_DISPOSITION_NOMEM; } /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, * the association is automatically closed by starting the shutdown process. * The work that needs to be done is same as when SHUTDOWN is initiated by * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). */ sctp_disposition_t sctp_sf_autoclose_timer_expire( const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { int disposition; /* From 9.2 Shutdown of an Association * Upon receipt of the SHUTDOWN primitive from its upper * layer, the endpoint enters SHUTDOWN-PENDING state and * remains there until all outstanding data has been * acknowledged by its peer. The endpoint accepts no new data * from its upper layer, but retransmits data to the far end * if necessary to fill gaps. */ sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); /* sctpimpguide-05 Section 2.12.2 * The sender of the SHUTDOWN MAY also start an overall guard timer * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. */ sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); disposition = SCTP_DISPOSITION_CONSUME; if (sctp_outq_is_empty(&asoc->outqueue)) { disposition = sctp_sf_do_9_2_start_shutdown(ep, asoc, type, arg, commands); } return disposition; } /***************************************************************************** * These are sa state functions which could apply to all types of events. ****************************************************************************/ /* * This table entry is not implemented. * * Inputs * (endpoint, asoc, chunk) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_not_impl(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { return SCTP_DISPOSITION_NOT_IMPL; } /* * This table entry represents a bug. * * Inputs * (endpoint, asoc, chunk) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_bug(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { return SCTP_DISPOSITION_BUG; } /* * This table entry represents the firing of a timer in the wrong state. * Since timer deletion cannot be guaranteed a timer 'may' end up firing * when the association is in the wrong state. This event should * be ignored, so as to prevent any rearming of the timer. * * Inputs * (endpoint, asoc, chunk) * * The return value is the disposition of the chunk. */ sctp_disposition_t sctp_sf_timer_ignore(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const sctp_subtype_t type, void *arg, sctp_cmd_seq_t *commands) { SCTP_DEBUG_PRINTK("Timer %d ignored.\n", type.chunk); return SCTP_DISPOSITION_CONSUME; } /******************************************************************** * 2nd Level Abstractions ********************************************************************/ /* Pull the SACK chunk based on the SACK header. */ struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) { struct sctp_sackhdr *sack; unsigned int len; __u16 num_blocks; __u16 num_dup_tsns; /* Protect ourselves from reading too far into * the skb from a bogus sender. */ sack = (struct sctp_sackhdr *) chunk->skb->data; num_blocks = ntohs(sack->num_gap_ack_blocks); num_dup_tsns = ntohs(sack->num_dup_tsns); len = sizeof(struct sctp_sackhdr); len = (num_blocks + num_dup_tsns) * sizeof(__u32); if (len > chunk->skb->len) return NULL; skb_pull(chunk->skb, len); return sack; } /* Create an ABORT packet to be sent as a response, with the specified * error causes. */ struct sctp_packet *sctp_abort_pkt_new(const struct sctp_endpoint *ep, const struct sctp_association *asoc, struct sctp_chunk *chunk, const void *payload, size_t paylen) { struct sctp_packet *packet; struct sctp_chunk *abort; packet = sctp_ootb_pkt_new(asoc, chunk); if (packet) { /* Make an ABORT. * The T bit will be set if the asoc is NULL. */ abort = sctp_make_abort(asoc, chunk, paylen); if (!abort) { sctp_ootb_pkt_free(packet); return NULL; } /* Add specified error causes, i.e., payload, to the * end of the chunk. */ sctp_addto_chunk(abort, paylen, payload); /* Set the skb to the belonging sock for accounting. */ abort->skb->sk = ep->base.sk; sctp_packet_append_chunk(packet, abort); } return packet; } /* Allocate a packet for responding in the OOTB conditions. */ struct sctp_packet *sctp_ootb_pkt_new(const struct sctp_association *asoc, const struct sctp_chunk *chunk) { struct sctp_packet *packet; struct sctp_transport *transport; __u16 sport; __u16 dport; __u32 vtag; /* Get the source and destination port from the inbound packet. */ sport = ntohs(chunk->sctp_hdr->dest); dport = ntohs(chunk->sctp_hdr->source); /* The V-tag is going to be the same as the inbound packet if no * association exists, otherwise, use the peer's vtag. */ if (asoc) { vtag = asoc->peer.i.init_tag; } else { /* Special case the INIT and stale COOKIE_ECHO as there is no * vtag yet. */ switch(chunk->chunk_hdr->type) { case SCTP_CID_INIT: { sctp_init_chunk_t *init; init = (sctp_init_chunk_t *)chunk->chunk_hdr; vtag = ntohl(init->init_hdr.init_tag); break; } default: vtag = ntohl(chunk->sctp_hdr->vtag); break; } } /* Make a transport for the bucket, Eliza... */ transport = sctp_transport_new(sctp_source(chunk), GFP_ATOMIC); if (!transport) goto nomem; /* Allocate a new packet for sending the response. */ packet = t_new(struct sctp_packet, GFP_ATOMIC); if (!packet) goto nomem_packet; /* Cache a route for the transport with the chunk's destination as * the source address. */ sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, sctp_sk(sctp_get_ctl_sock())); packet = sctp_packet_init(packet, transport, sport, dport); packet = sctp_packet_config(packet, vtag, 0, NULL); return packet; nomem_packet: sctp_transport_free(transport); nomem: return NULL; } /* Free the packet allocated earlier for responding in the OOTB condition. */ void sctp_ootb_pkt_free(struct sctp_packet *packet) { sctp_transport_free(packet->transport); sctp_packet_free(packet); } /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ void sctp_send_stale_cookie_err(const struct sctp_endpoint *ep, const struct sctp_association *asoc, const struct sctp_chunk *chunk, sctp_cmd_seq_t *commands, struct sctp_chunk *err_chunk) { struct sctp_packet *packet; if (err_chunk) { packet = sctp_ootb_pkt_new(asoc, chunk); if (packet) { struct sctp_signed_cookie *cookie; /* Override the OOTB vtag from the cookie. */ cookie = chunk->subh.cookie_hdr; packet->vtag = cookie->c.peer_vtag; /* Set the skb to the belonging sock for accounting. */ err_chunk->skb->sk = ep->base.sk; sctp_packet_append_chunk(packet, err_chunk); sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet)); SCTP_INC_STATS(SctpOutCtrlChunks); } else sctp_chunk_free (err_chunk); } }