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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [net/] [sctp/] [outqueue.c] - Rev 1765
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/* SCTP kernel reference Implementation * Copyright (c) 1999-2000 Cisco, Inc. * Copyright (c) 1999-2001 Motorola, Inc. * Copyright (c) 2001-2003 Intel Corp. * Copyright (c) 2001-2003 International Business Machines Corp. * * This file is part of the SCTP kernel reference Implementation * * These functions implement the sctp_outq class. The outqueue handles * bundling and queueing of outgoing SCTP chunks. * * 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> * Perry Melange <pmelange@null.cc.uic.edu> * Xingang Guo <xingang.guo@intel.com> * Hui Huang <hui.huang@nokia.com> * Sridhar Samudrala <sri@us.ibm.com> * Jon Grimm <jgrimm@us.ibm.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/list.h> /* For struct list_head */ #include <linux/socket.h> #include <linux/ip.h> #include <net/sock.h> /* For skb_set_owner_w */ #include <net/sctp/sctp.h> #include <net/sctp/sm.h> /* Declare internal functions here. */ static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn); static void sctp_check_transmitted(struct sctp_outq *q, struct list_head *transmitted_queue, struct sctp_transport *transport, struct sctp_sackhdr *sack, __u32 highest_new_tsn); static void sctp_mark_missing(struct sctp_outq *q, struct list_head *transmitted_queue, struct sctp_transport *transport, __u32 highest_new_tsn, int count_of_newacks); /* Add data to the front of the queue. */ static inline void sctp_outq_head_data(struct sctp_outq *q, struct sctp_chunk *ch) { __skb_queue_head(&q->out, (struct sk_buff *)ch); q->out_qlen += ch->skb->len; return; } /* Take data from the front of the queue. */ static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q) { struct sctp_chunk *ch; ch = (struct sctp_chunk *)__skb_dequeue(&q->out); if (ch) q->out_qlen -= ch->skb->len; return ch; } /* Add data chunk to the end of the queue. */ static inline void sctp_outq_tail_data(struct sctp_outq *q, struct sctp_chunk *ch) { __skb_queue_tail(&q->out, (struct sk_buff *)ch); q->out_qlen += ch->skb->len; return; } /* Insert a chunk behind chunk 'pos'. */ static inline void sctp_outq_insert_data(struct sctp_outq *q, struct sctp_chunk *ch, struct sctp_chunk *pos) { __skb_insert((struct sk_buff *)ch, (struct sk_buff *)pos->prev, (struct sk_buff *)pos, pos->list); q->out_qlen += ch->skb->len; } /* * SFR-CACC algorithm: * D) If count_of_newacks is greater than or equal to 2 * and t was not sent to the current primary then the * sender MUST NOT increment missing report count for t. */ static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary, struct sctp_transport *transport, int count_of_newacks) { if (count_of_newacks >=2 && transport != primary) return 1; return 0; } /* * SFR-CACC algorithm: * F) If count_of_newacks is less than 2, let d be the * destination to which t was sent. If cacc_saw_newack * is 0 for destination d, then the sender MUST NOT * increment missing report count for t. */ static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport, int count_of_newacks) { if (count_of_newacks < 2 && !transport->cacc.cacc_saw_newack) return 1; return 0; } /* * SFR-CACC algorithm: * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD * execute steps C, D, F. * * C has been implemented in sctp_outq_sack */ static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary, struct sctp_transport *transport, int count_of_newacks) { if (!primary->cacc.cycling_changeover) { if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks)) return 1; if (sctp_cacc_skip_3_1_f(transport, count_of_newacks)) return 1; return 0; } return 0; } /* * SFR-CACC algorithm: * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less * than next_tsn_at_change of the current primary, then * the sender MUST NOT increment missing report count * for t. */ static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn) { if (primary->cacc.cycling_changeover && TSN_lt(tsn, primary->cacc.next_tsn_at_change)) return 1; return 0; } /* * SFR-CACC algorithm: * 3) If the missing report count for TSN t is to be * incremented according to [RFC2960] and * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set, * then the sender MUST futher execute steps 3.1 and * 3.2 to determine if the missing report count for * TSN t SHOULD NOT be incremented. * * 3.3) If 3.1 and 3.2 do not dictate that the missing * report count for t should not be incremented, then * the sender SOULD increment missing report count for * t (according to [RFC2960] and [SCTP_STEWART_2002]). */ static inline int sctp_cacc_skip(struct sctp_transport *primary, struct sctp_transport *transport, int count_of_newacks, __u32 tsn) { if (primary->cacc.changeover_active && (sctp_cacc_skip_3_1(primary, transport, count_of_newacks) || sctp_cacc_skip_3_2(primary, tsn))) return 1; return 0; } /* Generate a new outqueue. */ struct sctp_outq *sctp_outq_new(struct sctp_association *asoc) { struct sctp_outq *q; q = t_new(struct sctp_outq, GFP_KERNEL); if (q) { sctp_outq_init(asoc, q); q->malloced = 1; } return q; } /* Initialize an existing sctp_outq. This does the boring stuff. * You still need to define handlers if you really want to DO * something with this structure... */ void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q) { q->asoc = asoc; skb_queue_head_init(&q->out); skb_queue_head_init(&q->control); INIT_LIST_HEAD(&q->retransmit); INIT_LIST_HEAD(&q->sacked); q->init_output = NULL; q->config_output = NULL; q->append_output = NULL; q->build_output = NULL; q->force_output = NULL; q->outstanding_bytes = 0; q->empty = 1; q->cork = 0; q->malloced = 0; q->out_qlen = 0; } /* Free the outqueue structure and any related pending chunks. */ void sctp_outq_teardown(struct sctp_outq *q) { struct sctp_transport *transport; struct list_head *lchunk, *pos, *temp; struct sctp_chunk *chunk; /* Throw away unacknowledged chunks. */ list_for_each(pos, &q->asoc->peer.transport_addr_list) { transport = list_entry(pos, struct sctp_transport, transports); while ((lchunk = sctp_list_dequeue(&transport->transmitted))) { chunk = list_entry(lchunk, struct sctp_chunk, transmitted_list); /* Mark as part of a failed message. */ sctp_datamsg_fail(chunk, q->error); sctp_chunk_free(chunk); } } /* Throw away chunks that have been gap ACKed. */ list_for_each_safe(lchunk, temp, &q->sacked) { list_del_init(lchunk); chunk = list_entry(lchunk, struct sctp_chunk, transmitted_list); sctp_datamsg_fail(chunk, q->error); sctp_chunk_free(chunk); } /* Throw away any chunks in the retransmit queue. */ list_for_each_safe(lchunk, temp, &q->retransmit) { list_del_init(lchunk); chunk = list_entry(lchunk, struct sctp_chunk, transmitted_list); sctp_datamsg_fail(chunk, q->error); sctp_chunk_free(chunk); } /* Throw away any leftover data chunks. */ while ((chunk = sctp_outq_dequeue_data(q))) { /* Mark as send failure. */ sctp_datamsg_fail(chunk, q->error); sctp_chunk_free(chunk); } q->error = 0; /* Throw away any leftover control chunks. */ while ((chunk = (struct sctp_chunk *) skb_dequeue(&q->control))) sctp_chunk_free(chunk); } /* Free the outqueue structure and any related pending chunks. */ void sctp_outq_free(struct sctp_outq *q) { /* Throw away leftover chunks. */ sctp_outq_teardown(q); /* If we were kmalloc()'d, free the memory. */ if (q->malloced) kfree(q); } /* Put a new chunk in an sctp_outq. */ int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk) { int error = 0; SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n", q, chunk, chunk && chunk->chunk_hdr ? sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) : "Illegal Chunk"); /* If it is data, queue it up, otherwise, send it * immediately. */ if (SCTP_CID_DATA == chunk->chunk_hdr->type) { /* Is it OK to queue data chunks? */ /* From 9. Termination of Association * * When either endpoint performs a shutdown, the * association on each peer will stop accepting new * data from its user and only deliver data in queue * at the time of sending or receiving the SHUTDOWN * chunk. */ switch (q->asoc->state) { case SCTP_STATE_EMPTY: case SCTP_STATE_CLOSED: case SCTP_STATE_SHUTDOWN_PENDING: case SCTP_STATE_SHUTDOWN_SENT: case SCTP_STATE_SHUTDOWN_RECEIVED: case SCTP_STATE_SHUTDOWN_ACK_SENT: /* Cannot send after transport endpoint shutdown */ error = -ESHUTDOWN; break; default: SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n", q, chunk, chunk && chunk->chunk_hdr ? sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) : "Illegal Chunk"); sctp_outq_tail_data(q, chunk); if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) SCTP_INC_STATS(SctpOutUnorderChunks); else SCTP_INC_STATS(SctpOutOrderChunks); q->empty = 0; break; }; } else { __skb_queue_tail(&q->control, (struct sk_buff *) chunk); SCTP_INC_STATS(SctpOutCtrlChunks); } if (error < 0) return error; if (!q->cork) error = sctp_outq_flush(q, 0); return error; } /* Insert a chunk into the retransmit queue. Chunks on the retransmit * queue are kept in order, based on the TSNs. */ void sctp_retransmit_insert(struct list_head *tlchunk, struct sctp_outq *q) { struct list_head *rlchunk; struct sctp_chunk *tchunk, *rchunk; __u32 ttsn, rtsn; int done = 0; tchunk = list_entry(tlchunk, struct sctp_chunk, transmitted_list); ttsn = ntohl(tchunk->subh.data_hdr->tsn); list_for_each(rlchunk, &q->retransmit) { rchunk = list_entry(rlchunk, struct sctp_chunk, transmitted_list); rtsn = ntohl(rchunk->subh.data_hdr->tsn); if (TSN_lt(ttsn, rtsn)) { list_add(tlchunk, rlchunk->prev); done = 1; break; } } if (!done) { list_add_tail(tlchunk, &q->retransmit); } } /* Mark all the eligible packets on a transport for retransmission. */ void sctp_retransmit_mark(struct sctp_outq *q, struct sctp_transport *transport, __u8 fast_retransmit) { struct list_head *lchunk, *ltemp; struct sctp_chunk *chunk; /* Walk through the specified transmitted queue. */ list_for_each_safe(lchunk, ltemp, &transport->transmitted) { chunk = list_entry(lchunk, struct sctp_chunk, transmitted_list); /* If we are doing retransmission due to a fast retransmit, * only the chunk's that are marked for fast retransmit * should be added to the retransmit queue. If we are doing * retransmission due to a timeout or pmtu discovery, only the * chunks that are not yet acked should be added to the * retransmit queue. */ if ((fast_retransmit && chunk->fast_retransmit) || (!fast_retransmit && !chunk->tsn_gap_acked)) { /* RFC 2960 6.2.1 Processing a Received SACK * * C) Any time a DATA chunk is marked for * retransmission (via either T3-rtx timer expiration * (Section 6.3.3) or via fast retransmit * (Section 7.2.4)), add the data size of those * chunks to the rwnd. */ q->asoc->peer.rwnd += sctp_data_size(chunk); q->outstanding_bytes -= sctp_data_size(chunk); transport->flight_size -= sctp_data_size(chunk); /* sctpimpguide-05 Section 2.8.2 * M5) If a T3-rtx timer expires, the * 'TSN.Missing.Report' of all affected TSNs is set * to 0. */ chunk->tsn_missing_report = 0; /* If a chunk that is being used for RTT measurement * has to be retransmitted, we cannot use this chunk * anymore for RTT measurements. Reset rto_pending so * that a new RTT measurement is started when a new * data chunk is sent. */ if (chunk->rtt_in_progress) { chunk->rtt_in_progress = 0; transport->rto_pending = 0; } /* Move the chunk to the retransmit queue. The chunks * on the retransmit queue is always kept in order. */ list_del_init(lchunk); sctp_retransmit_insert(lchunk, q); } } SCTP_DEBUG_PRINTK("%s: transport: %p, fast_retransmit: %d, " "cwnd: %d, ssthresh: %d, flight_size: %d, " "pba: %d\n", __FUNCTION__, transport, fast_retransmit, transport->cwnd, transport->ssthresh, transport->flight_size, transport->partial_bytes_acked); } /* Mark all the eligible packets on a transport for retransmission and force * one packet out. */ void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport, sctp_retransmit_reason_t reason) { int error = 0; __u8 fast_retransmit = 0; switch(reason) { case SCTP_RTXR_T3_RTX: sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX); /* Update the retran path if the T3-rtx timer has expired for * the current retran path. */ if (transport == transport->asoc->peer.retran_path) sctp_assoc_update_retran_path(transport->asoc); break; case SCTP_RTXR_FAST_RTX: sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX); fast_retransmit = 1; break; case SCTP_RTXR_PMTUD: default: break; } sctp_retransmit_mark(q, transport, fast_retransmit); error = sctp_outq_flush(q, /* rtx_timeout */ 1); if (error) q->asoc->base.sk->sk_err = -error; } /* * Transmit DATA chunks on the retransmit queue. Upon return from * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which * need to be transmitted by the caller. * We assume that pkt->transport has already been set. * * The return value is a normal kernel error return value. */ static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt, int rtx_timeout, int *start_timer) { struct list_head *lqueue; struct list_head *lchunk; struct sctp_transport *transport = pkt->transport; sctp_xmit_t status; struct sctp_chunk *chunk; struct sctp_association *asoc; int error = 0; asoc = q->asoc; lqueue = &q->retransmit; /* RFC 2960 6.3.3 Handle T3-rtx Expiration * * 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. * * [Just to be painfully clear, if we are retransmitting * because a timeout just happened, we should send only ONE * packet of retransmitted data.] */ lchunk = sctp_list_dequeue(lqueue); while (lchunk) { chunk = list_entry(lchunk, struct sctp_chunk, transmitted_list); /* Make sure that Gap Acked TSNs are not retransmitted. A * simple approach is just to move such TSNs out of the * way and into a 'transmitted' queue and skip to the * next chunk. */ if (chunk->tsn_gap_acked) { list_add_tail(lchunk, &transport->transmitted); lchunk = sctp_list_dequeue(lqueue); continue; } /* Attempt to append this chunk to the packet. */ status = (*q->append_output)(pkt, chunk); switch (status) { case SCTP_XMIT_PMTU_FULL: /* Send this packet. */ if ((error = (*q->force_output)(pkt)) == 0) *start_timer = 1; /* If we are retransmitting, we should only * send a single packet. */ if (rtx_timeout) { list_add(lchunk, lqueue); lchunk = NULL; } /* Bundle lchunk in the next round. */ break; case SCTP_XMIT_RWND_FULL: /* Send this packet. */ if ((error = (*q->force_output)(pkt)) == 0) *start_timer = 1; /* Stop sending DATA as there is no more room * at the receiver. */ list_add(lchunk, lqueue); lchunk = NULL; break; default: /* The append was successful, so add this chunk to * the transmitted list. */ list_add_tail(lchunk, &transport->transmitted); *start_timer = 1; q->empty = 0; /* Retrieve a new chunk to bundle. */ lchunk = sctp_list_dequeue(lqueue); break; }; } return error; } /* Cork the outqueue so queued chunks are really queued. */ int sctp_outq_uncork(struct sctp_outq *q) { int error = 0; if (q->cork) { q->cork = 0; error = sctp_outq_flush(q, 0); } return error; } /* * Try to flush an outqueue. * * Description: Send everything in q which we legally can, subject to * congestion limitations. * * Note: This function can be called from multiple contexts so appropriate * locking concerns must be made. Today we use the sock lock to protect * this function. */ int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout) { struct sctp_packet *packet; struct sctp_packet singleton; struct sctp_association *asoc = q->asoc; int ecn_capable = asoc->peer.ecn_capable; __u16 sport = asoc->base.bind_addr.port; __u16 dport = asoc->peer.port; __u32 vtag = asoc->peer.i.init_tag; /* This is the ECNE handler for singleton packets. */ sctp_packet_phandler_t *s_ecne_handler = NULL; sctp_packet_phandler_t *ecne_handler = NULL; struct sk_buff_head *queue; struct sctp_transport *transport = NULL; struct sctp_transport *new_transport; struct sctp_chunk *chunk; sctp_xmit_t status; int error = 0; int start_timer = 0; /* These transports have chunks to send. */ struct list_head transport_list; struct list_head *ltransport; INIT_LIST_HEAD(&transport_list); packet = NULL; /* * 6.10 Bundling * ... * When bundling control chunks with DATA chunks, an * endpoint MUST place control chunks first in the outbound * SCTP packet. The transmitter MUST transmit DATA chunks * within a SCTP packet in increasing order of TSN. * ... */ if (ecn_capable) { s_ecne_handler = &sctp_get_no_prepend; ecne_handler = &sctp_get_ecne_prepend; } queue = &q->control; while ((chunk = (struct sctp_chunk *)skb_dequeue(queue))) { /* Pick the right transport to use. */ new_transport = chunk->transport; if (!new_transport) { new_transport = asoc->peer.active_path; } else if (!new_transport->active) { /* If the chunk is Heartbeat, send it to * chunk->transport, even it's inactive. */ if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT) new_transport = asoc->peer.active_path; } /* Are we switching transports? * Take care of transport locks. */ if (new_transport != transport) { transport = new_transport; if (list_empty(&transport->send_ready)) { list_add_tail(&transport->send_ready, &transport_list); } packet = &transport->packet; (*q->config_output)(packet, vtag, ecn_capable, ecne_handler); } switch (chunk->chunk_hdr->type) { /* * 6.10 Bundling * ... * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN * COMPLETE with any other chunks. [Send them immediately.] */ case SCTP_CID_INIT: case SCTP_CID_INIT_ACK: case SCTP_CID_SHUTDOWN_COMPLETE: (*q->init_output)(&singleton, transport, sport, dport); (*q->config_output)(&singleton, vtag, ecn_capable, s_ecne_handler); (void) (*q->build_output)(&singleton, chunk); error = (*q->force_output)(&singleton); if (error < 0) return error; break; case SCTP_CID_ABORT: case SCTP_CID_SACK: case SCTP_CID_HEARTBEAT: case SCTP_CID_HEARTBEAT_ACK: case SCTP_CID_SHUTDOWN: case SCTP_CID_SHUTDOWN_ACK: case SCTP_CID_ERROR: case SCTP_CID_COOKIE_ECHO: case SCTP_CID_COOKIE_ACK: case SCTP_CID_ECN_ECNE: case SCTP_CID_ECN_CWR: (void) (*q->build_output)(packet, chunk); break; case SCTP_CID_ASCONF: case SCTP_CID_ASCONF_ACK: (void) (*q->build_output)(packet, chunk); break; default: /* We built a chunk with an illegal type! */ BUG(); }; } /* Is it OK to send data chunks? */ switch (asoc->state) { case SCTP_STATE_COOKIE_ECHOED: /* Only allow bundling when this packet has a COOKIE-ECHO * chunk. */ if (!packet || !packet->has_cookie_echo) break; /* fallthru */ case SCTP_STATE_ESTABLISHED: case SCTP_STATE_SHUTDOWN_PENDING: case SCTP_STATE_SHUTDOWN_RECEIVED: /* * RFC 2960 6.1 Transmission of DATA Chunks * * C) When the time comes for the sender to transmit, * before sending new DATA chunks, the sender MUST * first transmit any outstanding DATA chunks which * are marked for retransmission (limited by the * current cwnd). */ if (!list_empty(&q->retransmit)) { if (transport == asoc->peer.retran_path) goto retran; /* Switch transports & prepare the packet. */ transport = asoc->peer.retran_path; if (list_empty(&transport->send_ready)) { list_add_tail(&transport->send_ready, &transport_list); } packet = &transport->packet; (*q->config_output)(packet, vtag, ecn_capable, ecne_handler); retran: error = sctp_outq_flush_rtx(q, packet, rtx_timeout, &start_timer); if (start_timer) sctp_transport_reset_timers(transport); /* This can happen on COOKIE-ECHO resend. Only * one chunk can get bundled with a COOKIE-ECHO. */ if (packet->has_cookie_echo) goto sctp_flush_out; /* Don't send new data if there is still data * waiting to retransmit. */ if (!list_empty(&q->retransmit)) goto sctp_flush_out; } /* Finally, transmit new packets. */ start_timer = 0; queue = &q->out; while ((chunk = sctp_outq_dequeue_data(q))) { /* RFC 2960 6.5 Every DATA chunk MUST carry a valid * stream identifier. */ if (chunk->sinfo.sinfo_stream >= asoc->c.sinit_num_ostreams) { /* Mark as s failed send. */ sctp_datamsg_fail(chunk, SCTP_ERROR_INV_STRM); sctp_chunk_free(chunk); continue; } /* Has this chunk expired? */ if (sctp_datamsg_expires(chunk)) { sctp_datamsg_fail(chunk, 0); sctp_chunk_free(chunk); continue; } /* If there is a specified transport, use it. * Otherwise, we want to use the active path. */ new_transport = chunk->transport; if (!new_transport || !new_transport->active) new_transport = asoc->peer.active_path; /* Change packets if necessary. */ if (new_transport != transport) { transport = new_transport; /* Schedule to have this transport's * packet flushed. */ if (list_empty(&transport->send_ready)) { list_add_tail(&transport->send_ready, &transport_list); } packet = &transport->packet; (*q->config_output)(packet, vtag, ecn_capable, ecne_handler); } SCTP_DEBUG_PRINTK("sctp_transmit_packet(%p, %p[%s]), ", q, chunk, chunk && chunk->chunk_hdr ? sctp_cname(SCTP_ST_CHUNK( chunk->chunk_hdr->type)) : "Illegal Chunk"); SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head " "%p skb->users %d.\n", ntohl(chunk->subh.data_hdr->tsn), chunk->skb ?chunk->skb->head : 0, chunk->skb ? atomic_read(&chunk->skb->users) : -1); /* Add the chunk to the packet. */ status = (*q->build_output)(packet, chunk); switch (status) { case SCTP_XMIT_PMTU_FULL: case SCTP_XMIT_RWND_FULL: case SCTP_XMIT_NAGLE_DELAY: /* We could not append this chunk, so put * the chunk back on the output queue. */ SCTP_DEBUG_PRINTK("sctp_outq_flush: could " "not transmit TSN: 0x%x, status: %d\n", ntohl(chunk->subh.data_hdr->tsn), status); sctp_outq_head_data(q, chunk); goto sctp_flush_out; break; case SCTP_XMIT_OK: break; default: BUG(); } /* BUG: We assume that the (*q->force_output()) * call below will succeed all the time and add the * chunk to the transmitted list and restart the * timers. * It is possible that the call can fail under OOM * conditions. * * Is this really a problem? Won't this behave * like a lost TSN? */ list_add_tail(&chunk->transmitted_list, &transport->transmitted); sctp_transport_reset_timers(transport); q->empty = 0; /* Only let one DATA chunk get bundled with a * COOKIE-ECHO chunk. */ if (packet->has_cookie_echo) goto sctp_flush_out; } break; default: /* Do nothing. */ break; } sctp_flush_out: /* Before returning, examine all the transports touched in * this call. Right now, we bluntly force clear all the * transports. Things might change after we implement Nagle. * But such an examination is still required. * * --xguo */ while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) { struct sctp_transport *t = list_entry(ltransport, struct sctp_transport, send_ready); if (t != transport) transport = t; packet = &transport->packet; if (packet->size != SCTP_IP_OVERHEAD) error = (*q->force_output)(packet); } return error; } /* Set the various output handling callbacks. */ int sctp_outq_set_output_handlers(struct sctp_outq *q, sctp_outq_ohandler_init_t init, sctp_outq_ohandler_config_t config, sctp_outq_ohandler_t append, sctp_outq_ohandler_t build, sctp_outq_ohandler_force_t force) { q->init_output = init; q->config_output = config; q->append_output = append; q->build_output = build; q->force_output = force; return 0; } /* Update unack_data based on the incoming SACK chunk */ static void sctp_sack_update_unack_data(struct sctp_association *assoc, struct sctp_sackhdr *sack) { sctp_sack_variable_t *frags; __u16 unack_data; int i; unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1; frags = sack->variable; for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) { unack_data -= ((ntohs(frags[i].gab.end) - ntohs(frags[i].gab.start) + 1)); } assoc->unack_data = unack_data; } /* Return the highest new tsn that is acknowledged by the given SACK chunk. */ static __u32 sctp_highest_new_tsn(struct sctp_sackhdr *sack, struct sctp_association *asoc) { struct list_head *ltransport, *lchunk; struct sctp_transport *transport; struct sctp_chunk *chunk; __u32 highest_new_tsn, tsn; struct list_head *transport_list = &asoc->peer.transport_addr_list; highest_new_tsn = ntohl(sack->cum_tsn_ack); list_for_each(ltransport, transport_list) { transport = list_entry(ltransport, struct sctp_transport, transports); list_for_each(lchunk, &transport->transmitted) { chunk = list_entry(lchunk, struct sctp_chunk, transmitted_list); tsn = ntohl(chunk->subh.data_hdr->tsn); if (!chunk->tsn_gap_acked && TSN_lt(highest_new_tsn, tsn) && sctp_acked(sack, tsn)) highest_new_tsn = tsn; } } return highest_new_tsn; } /* This is where we REALLY process a SACK. * * Process the SACK against the outqueue. Mostly, this just frees * things off the transmitted queue. */ int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack) { struct sctp_association *asoc = q->asoc; struct sctp_transport *transport; struct sctp_chunk *tchunk; struct list_head *lchunk, *transport_list, *pos, *temp; sctp_sack_variable_t *frags = sack->variable; __u32 sack_ctsn, ctsn, tsn; __u32 highest_tsn, highest_new_tsn; __u32 sack_a_rwnd; unsigned outstanding; struct sctp_transport *primary = asoc->peer.primary_path; int count_of_newacks = 0; /* Grab the association's destination address list. */ transport_list = &asoc->peer.transport_addr_list; sack_ctsn = ntohl(sack->cum_tsn_ack); /* * SFR-CACC algorithm: * On receipt of a SACK the sender SHOULD execute the * following statements. * * 1) If the cumulative ack in the SACK passes next tsn_at_change * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for * all destinations. */ if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { primary->cacc.changeover_active = 0; list_for_each(pos, transport_list) { transport = list_entry(pos, struct sctp_transport, transports); transport->cacc.cycling_changeover = 0; } } /* * SFR-CACC algorithm: * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE * is set the receiver of the SACK MUST take the following actions: * * A) Initialize the cacc_saw_newack to 0 for all destination * addresses. */ if (sack->num_gap_ack_blocks > 0 && primary->cacc.changeover_active) { list_for_each(pos, transport_list) { transport = list_entry(pos, struct sctp_transport, transports); transport->cacc.cacc_saw_newack = 0; } } /* Get the highest TSN in the sack. */ highest_tsn = sack_ctsn + ntohs(frags[ntohs(sack->num_gap_ack_blocks) - 1].gab.end); if (TSN_lt(asoc->highest_sacked, highest_tsn)) { highest_new_tsn = highest_tsn; asoc->highest_sacked = highest_tsn; } else { highest_new_tsn = sctp_highest_new_tsn(sack, asoc); } /* Run through the retransmit queue. Credit bytes received * and free those chunks that we can. */ sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn); sctp_mark_missing(q, &q->retransmit, NULL, highest_new_tsn, 0); /* Run through the transmitted queue. * Credit bytes received and free those chunks which we can. * * This is a MASSIVE candidate for optimization. */ list_for_each(pos, transport_list) { transport = list_entry(pos, struct sctp_transport, transports); sctp_check_transmitted(q, &transport->transmitted, transport, sack, highest_new_tsn); /* * SFR-CACC algorithm: * C) Let count_of_newacks be the number of * destinations for which cacc_saw_newack is set. */ if (transport->cacc.cacc_saw_newack) count_of_newacks ++; } list_for_each(pos, transport_list) { transport = list_entry(pos, struct sctp_transport, transports); sctp_mark_missing(q, &transport->transmitted, transport, highest_new_tsn, count_of_newacks); } /* Move the Cumulative TSN Ack Point if appropriate. */ if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) asoc->ctsn_ack_point = sack_ctsn; /* Update unack_data field in the assoc. */ sctp_sack_update_unack_data(asoc, sack); ctsn = asoc->ctsn_ack_point; SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n", __FUNCTION__, sack_ctsn); SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association " "%p is 0x%x.\n", __FUNCTION__, asoc, ctsn); /* Throw away stuff rotting on the sack queue. */ list_for_each_safe(lchunk, temp, &q->sacked) { tchunk = list_entry(lchunk, struct sctp_chunk, transmitted_list); tsn = ntohl(tchunk->subh.data_hdr->tsn); if (TSN_lte(tsn, ctsn)) sctp_chunk_free(tchunk); } /* 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. */ sack_a_rwnd = ntohl(sack->a_rwnd); outstanding = q->outstanding_bytes; if (outstanding < sack_a_rwnd) sack_a_rwnd -= outstanding; else sack_a_rwnd = 0; asoc->peer.rwnd = sack_a_rwnd; /* See if all chunks are acked. * Make sure the empty queue handler will get run later. */ q->empty = skb_queue_empty(&q->out) && list_empty(&q->retransmit); if (!q->empty) goto finish; list_for_each(pos, transport_list) { transport = list_entry(pos, struct sctp_transport, transports); q->empty = q->empty && list_empty(&transport->transmitted); if (!q->empty) goto finish; } SCTP_DEBUG_PRINTK("sack queue is empty.\n"); finish: return q->empty; } /* Is the outqueue empty? */ int sctp_outq_is_empty(const struct sctp_outq *q) { return q->empty; } /******************************************************************** * 2nd Level Abstractions ********************************************************************/ /* Go through a transport's transmitted list or the association's retransmit * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked. * The retransmit list will not have an associated transport. * * I added coherent debug information output. --xguo * * Instead of printing 'sacked' or 'kept' for each TSN on the * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5. * KEPT TSN6-TSN7, etc. */ static void sctp_check_transmitted(struct sctp_outq *q, struct list_head *transmitted_queue, struct sctp_transport *transport, struct sctp_sackhdr *sack, __u32 highest_new_tsn_in_sack) { struct list_head *lchunk; struct sctp_chunk *tchunk; struct list_head tlist; __u32 tsn; __u32 sack_ctsn; __u32 rtt; __u8 restart_timer = 0; int bytes_acked = 0; /* These state variables are for coherent debug output. --xguo */ #if SCTP_DEBUG __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */ __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */ __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */ __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */ /* 0 : The last TSN was ACKed. * 1 : The last TSN was NOT ACKed (i.e. KEPT). * -1: We need to initialize. */ int dbg_prt_state = -1; #endif /* SCTP_DEBUG */ sack_ctsn = ntohl(sack->cum_tsn_ack); INIT_LIST_HEAD(&tlist); /* The while loop will skip empty transmitted queues. */ while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) { tchunk = list_entry(lchunk, struct sctp_chunk, transmitted_list); tsn = ntohl(tchunk->subh.data_hdr->tsn); if (sctp_acked(sack, tsn)) { /* If this queue is the retransmit queue, the * retransmit timer has already reclaimed * the outstanding bytes for this chunk, so only * count bytes associated with a transport. */ if (transport) { /* If this chunk is being used for RTT * measurement, calculate the RTT and update * the RTO using this value. * * 6.3.1 C5) Karn's algorithm: RTT measurements * MUST NOT be made using packets that were * retransmitted (and thus for which it is * ambiguous whether the reply was for the * first instance of the packet or a later * instance). */ if (!tchunk->tsn_gap_acked && !tchunk->resent && tchunk->rtt_in_progress) { rtt = jiffies - tchunk->sent_at; sctp_transport_update_rto(transport, rtt); } } if (TSN_lte(tsn, sack_ctsn)) { /* RFC 2960 6.3.2 Retransmission Timer Rules * * R3) Whenever a SACK is received * that acknowledges the DATA chunk * with the earliest outstanding TSN * for that address, restart T3-rtx * timer for that address with its * current RTO. */ restart_timer = 1; if (!tchunk->tsn_gap_acked) { tchunk->tsn_gap_acked = 1; bytes_acked += sctp_data_size(tchunk); /* * SFR-CACC algorithm: * 2) If the SACK contains gap acks * and the flag CHANGEOVER_ACTIVE is * set the receiver of the SACK MUST * take the following action: * * B) For each TSN t being acked that * has not been acked in any SACK so * far, set cacc_saw_newack to 1 for * the destination that the TSN was * sent to. */ if (transport && sack->num_gap_ack_blocks && q->asoc->peer.primary_path->cacc. changeover_active) transport->cacc.cacc_saw_newack = 1; } list_add_tail(&tchunk->transmitted_list, &q->sacked); } else { /* RFC2960 7.2.4, sctpimpguide-05 2.8.2 * M2) Each time a SACK arrives reporting * 'Stray DATA chunk(s)' record the highest TSN * reported as newly acknowledged, call this * value 'HighestTSNinSack'. A newly * acknowledged DATA chunk is one not * previously acknowledged in a SACK. * * When the SCTP sender of data receives a SACK * chunk that acknowledges, for the first time, * the receipt of a DATA chunk, all the still * unacknowledged DATA chunks whose TSN is * older than that newly acknowledged DATA * chunk, are qualified as 'Stray DATA chunks'. */ if (!tchunk->tsn_gap_acked) { tchunk->tsn_gap_acked = 1; bytes_acked += sctp_data_size(tchunk); } list_add_tail(lchunk, &tlist); } #if SCTP_DEBUG switch (dbg_prt_state) { case 0: /* last TSN was ACKed */ if (dbg_last_ack_tsn + 1 == tsn) { /* This TSN belongs to the * current ACK range. */ break; } if (dbg_last_ack_tsn != dbg_ack_tsn) { /* Display the end of the * current range. */ SCTP_DEBUG_PRINTK("-%08x", dbg_last_ack_tsn); } /* Start a new range. */ SCTP_DEBUG_PRINTK(",%08x", tsn); dbg_ack_tsn = tsn; break; case 1: /* The last TSN was NOT ACKed. */ if (dbg_last_kept_tsn != dbg_kept_tsn) { /* Display the end of current range. */ SCTP_DEBUG_PRINTK("-%08x", dbg_last_kept_tsn); } SCTP_DEBUG_PRINTK("\n"); /* FALL THROUGH... */ default: /* This is the first-ever TSN we examined. */ /* Start a new range of ACK-ed TSNs. */ SCTP_DEBUG_PRINTK("ACKed: %08x", tsn); dbg_prt_state = 0; dbg_ack_tsn = tsn; }; dbg_last_ack_tsn = tsn; #endif /* SCTP_DEBUG */ } else { if (tchunk->tsn_gap_acked) { SCTP_DEBUG_PRINTK("%s: Receiver reneged on " "data TSN: 0x%x\n", __FUNCTION__, tsn); tchunk->tsn_gap_acked = 0; bytes_acked -= sctp_data_size(tchunk); /* RFC 2960 6.3.2 Retransmission Timer Rules * * R4) Whenever a SACK is received missing a * TSN that was previously acknowledged via a * Gap Ack Block, start T3-rtx for the * destination address to which the DATA * chunk was originally * transmitted if it is not already running. */ restart_timer = 1; } list_add_tail(lchunk, &tlist); #if SCTP_DEBUG /* See the above comments on ACK-ed TSNs. */ switch (dbg_prt_state) { case 1: if (dbg_last_kept_tsn + 1 == tsn) break; if (dbg_last_kept_tsn != dbg_kept_tsn) SCTP_DEBUG_PRINTK("-%08x", dbg_last_kept_tsn); SCTP_DEBUG_PRINTK(",%08x", tsn); dbg_kept_tsn = tsn; break; case 0: if (dbg_last_ack_tsn != dbg_ack_tsn) SCTP_DEBUG_PRINTK("-%08x", dbg_last_ack_tsn); SCTP_DEBUG_PRINTK("\n"); /* FALL THROUGH... */ default: SCTP_DEBUG_PRINTK("KEPT: %08x",tsn); dbg_prt_state = 1; dbg_kept_tsn = tsn; }; dbg_last_kept_tsn = tsn; #endif /* SCTP_DEBUG */ } } #if SCTP_DEBUG /* Finish off the last range, displaying its ending TSN. */ switch (dbg_prt_state) { case 0: if (dbg_last_ack_tsn != dbg_ack_tsn) { SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn); } else { SCTP_DEBUG_PRINTK("\n"); } break; case 1: if (dbg_last_kept_tsn != dbg_kept_tsn) { SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn); } else { SCTP_DEBUG_PRINTK("\n"); } }; #endif /* SCTP_DEBUG */ if (transport) { if (bytes_acked) { /* 8.2. When an outstanding TSN is acknowledged, * the endpoint shall clear the error counter of * the destination transport address to which the * DATA chunk was last sent. * The association's overall error counter is * also cleared. */ transport->error_count = 0; transport->asoc->overall_error_count = 0; /* Mark the destination transport address as * active if it is not so marked. */ if (!transport->active) { sctp_assoc_control_transport( transport->asoc, transport, SCTP_TRANSPORT_UP, SCTP_RECEIVED_SACK); } sctp_transport_raise_cwnd(transport, sack_ctsn, bytes_acked); transport->flight_size -= bytes_acked; q->outstanding_bytes -= bytes_acked; } else { /* RFC 2960 6.1, sctpimpguide-06 2.15.2 * When a sender is doing zero window probing, it * should not timeout the association if it continues * to receive new packets from the receiver. The * reason is that the receiver MAY keep its window * closed for an indefinite time. * A sender is doing zero window probing when the * receiver's advertised window is zero, and there is * only one data chunk in flight to the receiver. */ if (!q->asoc->peer.rwnd && !list_empty(&tlist) && (sack_ctsn+2 == q->asoc->next_tsn)) { SCTP_DEBUG_PRINTK("%s: SACK received for zero " "window probe: %u\n", __FUNCTION__, sack_ctsn); q->asoc->overall_error_count = 0; transport->error_count = 0; } } /* RFC 2960 6.3.2 Retransmission Timer Rules * * R2) Whenever all outstanding data sent to an address have * been acknowledged, turn off the T3-rtx timer of that * address. */ if (!transport->flight_size) { if (timer_pending(&transport->T3_rtx_timer) && del_timer(&transport->T3_rtx_timer)) { sctp_transport_put(transport); } } else if (restart_timer) { if (!mod_timer(&transport->T3_rtx_timer, jiffies + transport->rto)) sctp_transport_hold(transport); } } list_splice(&tlist, transmitted_queue); } /* Mark chunks as missing and consequently may get retransmitted. */ static void sctp_mark_missing(struct sctp_outq *q, struct list_head *transmitted_queue, struct sctp_transport *transport, __u32 highest_new_tsn_in_sack, int count_of_newacks) { struct sctp_chunk *chunk; struct list_head *pos; __u32 tsn; char do_fast_retransmit = 0; struct sctp_transport *primary = q->asoc->peer.primary_path; list_for_each(pos, transmitted_queue) { chunk = list_entry(pos, struct sctp_chunk, transmitted_list); tsn = ntohl(chunk->subh.data_hdr->tsn); /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all * 'Unacknowledged TSN's', if the TSN number of an * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack' * value, increment the 'TSN.Missing.Report' count on that * chunk if it has NOT been fast retransmitted or marked for * fast retransmit already. */ if (!chunk->fast_retransmit && !chunk->tsn_gap_acked && TSN_lt(tsn, highest_new_tsn_in_sack)) { /* SFR-CACC may require us to skip marking * this chunk as missing. */ if (!transport || !sctp_cacc_skip(primary, transport, count_of_newacks, tsn)) { chunk->tsn_missing_report++; SCTP_DEBUG_PRINTK( "%s: TSN 0x%x missing counter: %d\n", __FUNCTION__, tsn, chunk->tsn_missing_report); } } /* * M4) If any DATA chunk is found to have a * 'TSN.Missing.Report' * value larger than or equal to 4, mark that chunk for * retransmission and start the fast retransmit procedure. */ if (chunk->tsn_missing_report >= 4) { chunk->fast_retransmit = 1; do_fast_retransmit = 1; } } if (transport) { if (do_fast_retransmit) sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX); SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, " "ssthresh: %d, flight_size: %d, pba: %d\n", __FUNCTION__, transport, transport->cwnd, transport->ssthresh, transport->flight_size, transport->partial_bytes_acked); } } /* Is the given TSN acked by this packet? */ static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) { int i; sctp_sack_variable_t *frags; __u16 gap; __u32 ctsn = ntohl(sack->cum_tsn_ack); if (TSN_lte(tsn, ctsn)) goto pass; /* 3.3.4 Selective Acknowledgement (SACK) (3): * * Gap Ack Blocks: * These fields contain the Gap Ack Blocks. They are repeated * for each Gap Ack Block up to the number of Gap Ack Blocks * defined in the Number of Gap Ack Blocks field. All DATA * chunks with TSNs greater than or equal to (Cumulative TSN * Ack + Gap Ack Block Start) and less than or equal to * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack * Block are assumed to have been received correctly. */ frags = sack->variable; gap = tsn - ctsn; for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) { if (TSN_lte(ntohs(frags[i].gab.start), gap) && TSN_lte(gap, ntohs(frags[i].gab.end))) goto pass; } return 0; pass: return 1; }