| 1 |
62 |
marcus.erl |
/*
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| 2 |
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* net/dccp/input.c
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| 3 |
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*
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* An implementation of the DCCP protocol
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| 5 |
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* Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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| 6 |
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*
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* This program is free software; you can redistribute it and/or
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| 8 |
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* modify it under the terms of the GNU General Public License
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| 9 |
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* as published by the Free Software Foundation; either version
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| 10 |
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* 2 of the License, or (at your option) any later version.
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*/
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| 13 |
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#include <linux/dccp.h>
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| 14 |
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#include <linux/skbuff.h>
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| 15 |
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| 16 |
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#include <net/sock.h>
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| 17 |
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| 18 |
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#include "ackvec.h"
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| 19 |
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#include "ccid.h"
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| 20 |
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#include "dccp.h"
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| 21 |
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| 22 |
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/* rate-limit for syncs in reply to sequence-invalid packets; RFC 4340, 7.5.4 */
|
| 23 |
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int sysctl_dccp_sync_ratelimit __read_mostly = HZ / 8;
|
| 24 |
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| 25 |
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static void dccp_fin(struct sock *sk, struct sk_buff *skb)
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| 26 |
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{
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| 27 |
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sk->sk_shutdown |= RCV_SHUTDOWN;
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| 28 |
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sock_set_flag(sk, SOCK_DONE);
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| 29 |
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__skb_pull(skb, dccp_hdr(skb)->dccph_doff * 4);
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| 30 |
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__skb_queue_tail(&sk->sk_receive_queue, skb);
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| 31 |
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skb_set_owner_r(skb, sk);
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| 32 |
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sk->sk_data_ready(sk, 0);
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| 33 |
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}
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| 34 |
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| 35 |
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static void dccp_rcv_close(struct sock *sk, struct sk_buff *skb)
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| 36 |
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{
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| 37 |
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dccp_send_reset(sk, DCCP_RESET_CODE_CLOSED);
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| 38 |
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dccp_fin(sk, skb);
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| 39 |
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dccp_set_state(sk, DCCP_CLOSED);
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| 40 |
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sk_wake_async(sk, 1, POLL_HUP);
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| 41 |
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}
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| 42 |
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| 43 |
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static void dccp_rcv_closereq(struct sock *sk, struct sk_buff *skb)
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| 44 |
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{
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| 45 |
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/*
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| 46 |
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* Step 7: Check for unexpected packet types
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| 47 |
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* If (S.is_server and P.type == CloseReq)
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| 48 |
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* Send Sync packet acknowledging P.seqno
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| 49 |
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* Drop packet and return
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| 50 |
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*/
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| 51 |
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if (dccp_sk(sk)->dccps_role != DCCP_ROLE_CLIENT) {
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| 52 |
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dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq, DCCP_PKT_SYNC);
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| 53 |
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return;
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| 54 |
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}
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| 55 |
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| 56 |
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if (sk->sk_state != DCCP_CLOSING)
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| 57 |
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dccp_set_state(sk, DCCP_CLOSING);
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| 58 |
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dccp_send_close(sk, 0);
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| 59 |
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}
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| 60 |
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| 61 |
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static u8 dccp_reset_code_convert(const u8 code)
|
| 62 |
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{
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| 63 |
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const u8 error_code[] = {
|
| 64 |
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[DCCP_RESET_CODE_CLOSED] = 0, /* normal termination */
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| 65 |
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[DCCP_RESET_CODE_UNSPECIFIED] = 0, /* nothing known */
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| 66 |
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[DCCP_RESET_CODE_ABORTED] = ECONNRESET,
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| 67 |
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| 68 |
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[DCCP_RESET_CODE_NO_CONNECTION] = ECONNREFUSED,
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| 69 |
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[DCCP_RESET_CODE_CONNECTION_REFUSED] = ECONNREFUSED,
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| 70 |
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[DCCP_RESET_CODE_TOO_BUSY] = EUSERS,
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| 71 |
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[DCCP_RESET_CODE_AGGRESSION_PENALTY] = EDQUOT,
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| 72 |
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| 73 |
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[DCCP_RESET_CODE_PACKET_ERROR] = ENOMSG,
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| 74 |
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[DCCP_RESET_CODE_BAD_INIT_COOKIE] = EBADR,
|
| 75 |
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[DCCP_RESET_CODE_BAD_SERVICE_CODE] = EBADRQC,
|
| 76 |
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[DCCP_RESET_CODE_OPTION_ERROR] = EILSEQ,
|
| 77 |
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[DCCP_RESET_CODE_MANDATORY_ERROR] = EOPNOTSUPP,
|
| 78 |
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};
|
| 79 |
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|
| 80 |
|
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return code >= DCCP_MAX_RESET_CODES ? 0 : error_code[code];
|
| 81 |
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}
|
| 82 |
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|
| 83 |
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static void dccp_rcv_reset(struct sock *sk, struct sk_buff *skb)
|
| 84 |
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{
|
| 85 |
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u8 err = dccp_reset_code_convert(dccp_hdr_reset(skb)->dccph_reset_code);
|
| 86 |
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|
|
| 87 |
|
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sk->sk_err = err;
|
| 88 |
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|
| 89 |
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/* Queue the equivalent of TCP fin so that dccp_recvmsg exits the loop */
|
| 90 |
|
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dccp_fin(sk, skb);
|
| 91 |
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|
|
| 92 |
|
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if (err && !sock_flag(sk, SOCK_DEAD))
|
| 93 |
|
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sk_wake_async(sk, 0, POLL_ERR);
|
| 94 |
|
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dccp_time_wait(sk, DCCP_TIME_WAIT, 0);
|
| 95 |
|
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}
|
| 96 |
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|
| 97 |
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static void dccp_event_ack_recv(struct sock *sk, struct sk_buff *skb)
|
| 98 |
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{
|
| 99 |
|
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struct dccp_sock *dp = dccp_sk(sk);
|
| 100 |
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|
|
| 101 |
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if (dccp_msk(sk)->dccpms_send_ack_vector)
|
| 102 |
|
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dccp_ackvec_check_rcv_ackno(dp->dccps_hc_rx_ackvec, sk,
|
| 103 |
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DCCP_SKB_CB(skb)->dccpd_ack_seq);
|
| 104 |
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}
|
| 105 |
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|
| 106 |
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static int dccp_check_seqno(struct sock *sk, struct sk_buff *skb)
|
| 107 |
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{
|
| 108 |
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const struct dccp_hdr *dh = dccp_hdr(skb);
|
| 109 |
|
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struct dccp_sock *dp = dccp_sk(sk);
|
| 110 |
|
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u64 lswl, lawl, seqno = DCCP_SKB_CB(skb)->dccpd_seq,
|
| 111 |
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ackno = DCCP_SKB_CB(skb)->dccpd_ack_seq;
|
| 112 |
|
|
|
| 113 |
|
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/*
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| 114 |
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* Step 5: Prepare sequence numbers for Sync
|
| 115 |
|
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* If P.type == Sync or P.type == SyncAck,
|
| 116 |
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* If S.AWL <= P.ackno <= S.AWH and P.seqno >= S.SWL,
|
| 117 |
|
|
* / * P is valid, so update sequence number variables
|
| 118 |
|
|
* accordingly. After this update, P will pass the tests
|
| 119 |
|
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* in Step 6. A SyncAck is generated if necessary in
|
| 120 |
|
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* Step 15 * /
|
| 121 |
|
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* Update S.GSR, S.SWL, S.SWH
|
| 122 |
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* Otherwise,
|
| 123 |
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* Drop packet and return
|
| 124 |
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*/
|
| 125 |
|
|
if (dh->dccph_type == DCCP_PKT_SYNC ||
|
| 126 |
|
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dh->dccph_type == DCCP_PKT_SYNCACK) {
|
| 127 |
|
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if (between48(ackno, dp->dccps_awl, dp->dccps_awh) &&
|
| 128 |
|
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dccp_delta_seqno(dp->dccps_swl, seqno) >= 0)
|
| 129 |
|
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dccp_update_gsr(sk, seqno);
|
| 130 |
|
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else
|
| 131 |
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return -1;
|
| 132 |
|
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}
|
| 133 |
|
|
|
| 134 |
|
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/*
|
| 135 |
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* Step 6: Check sequence numbers
|
| 136 |
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* Let LSWL = S.SWL and LAWL = S.AWL
|
| 137 |
|
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* If P.type == CloseReq or P.type == Close or P.type == Reset,
|
| 138 |
|
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* LSWL := S.GSR + 1, LAWL := S.GAR
|
| 139 |
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* If LSWL <= P.seqno <= S.SWH
|
| 140 |
|
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* and (P.ackno does not exist or LAWL <= P.ackno <= S.AWH),
|
| 141 |
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* Update S.GSR, S.SWL, S.SWH
|
| 142 |
|
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* If P.type != Sync,
|
| 143 |
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* Update S.GAR
|
| 144 |
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*/
|
| 145 |
|
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lswl = dp->dccps_swl;
|
| 146 |
|
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lawl = dp->dccps_awl;
|
| 147 |
|
|
|
| 148 |
|
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if (dh->dccph_type == DCCP_PKT_CLOSEREQ ||
|
| 149 |
|
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dh->dccph_type == DCCP_PKT_CLOSE ||
|
| 150 |
|
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dh->dccph_type == DCCP_PKT_RESET) {
|
| 151 |
|
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lswl = ADD48(dp->dccps_gsr, 1);
|
| 152 |
|
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lawl = dp->dccps_gar;
|
| 153 |
|
|
}
|
| 154 |
|
|
|
| 155 |
|
|
if (between48(seqno, lswl, dp->dccps_swh) &&
|
| 156 |
|
|
(ackno == DCCP_PKT_WITHOUT_ACK_SEQ ||
|
| 157 |
|
|
between48(ackno, lawl, dp->dccps_awh))) {
|
| 158 |
|
|
dccp_update_gsr(sk, seqno);
|
| 159 |
|
|
|
| 160 |
|
|
if (dh->dccph_type != DCCP_PKT_SYNC &&
|
| 161 |
|
|
(ackno != DCCP_PKT_WITHOUT_ACK_SEQ))
|
| 162 |
|
|
dp->dccps_gar = ackno;
|
| 163 |
|
|
} else {
|
| 164 |
|
|
unsigned long now = jiffies;
|
| 165 |
|
|
/*
|
| 166 |
|
|
* Step 6: Check sequence numbers
|
| 167 |
|
|
* Otherwise,
|
| 168 |
|
|
* If P.type == Reset,
|
| 169 |
|
|
* Send Sync packet acknowledging S.GSR
|
| 170 |
|
|
* Otherwise,
|
| 171 |
|
|
* Send Sync packet acknowledging P.seqno
|
| 172 |
|
|
* Drop packet and return
|
| 173 |
|
|
*
|
| 174 |
|
|
* These Syncs are rate-limited as per RFC 4340, 7.5.4:
|
| 175 |
|
|
* at most 1 / (dccp_sync_rate_limit * HZ) Syncs per second.
|
| 176 |
|
|
*/
|
| 177 |
|
|
if (time_before(now, (dp->dccps_rate_last +
|
| 178 |
|
|
sysctl_dccp_sync_ratelimit)))
|
| 179 |
|
|
return 0;
|
| 180 |
|
|
|
| 181 |
|
|
DCCP_WARN("DCCP: Step 6 failed for %s packet, "
|
| 182 |
|
|
"(LSWL(%llu) <= P.seqno(%llu) <= S.SWH(%llu)) and "
|
| 183 |
|
|
"(P.ackno %s or LAWL(%llu) <= P.ackno(%llu) <= S.AWH(%llu), "
|
| 184 |
|
|
"sending SYNC...\n", dccp_packet_name(dh->dccph_type),
|
| 185 |
|
|
(unsigned long long) lswl, (unsigned long long) seqno,
|
| 186 |
|
|
(unsigned long long) dp->dccps_swh,
|
| 187 |
|
|
(ackno == DCCP_PKT_WITHOUT_ACK_SEQ) ? "doesn't exist"
|
| 188 |
|
|
: "exists",
|
| 189 |
|
|
(unsigned long long) lawl, (unsigned long long) ackno,
|
| 190 |
|
|
(unsigned long long) dp->dccps_awh);
|
| 191 |
|
|
|
| 192 |
|
|
dp->dccps_rate_last = now;
|
| 193 |
|
|
|
| 194 |
|
|
if (dh->dccph_type == DCCP_PKT_RESET)
|
| 195 |
|
|
seqno = dp->dccps_gsr;
|
| 196 |
|
|
dccp_send_sync(sk, seqno, DCCP_PKT_SYNC);
|
| 197 |
|
|
return -1;
|
| 198 |
|
|
}
|
| 199 |
|
|
|
| 200 |
|
|
return 0;
|
| 201 |
|
|
}
|
| 202 |
|
|
|
| 203 |
|
|
static int __dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
|
| 204 |
|
|
const struct dccp_hdr *dh, const unsigned len)
|
| 205 |
|
|
{
|
| 206 |
|
|
struct dccp_sock *dp = dccp_sk(sk);
|
| 207 |
|
|
|
| 208 |
|
|
switch (dccp_hdr(skb)->dccph_type) {
|
| 209 |
|
|
case DCCP_PKT_DATAACK:
|
| 210 |
|
|
case DCCP_PKT_DATA:
|
| 211 |
|
|
/*
|
| 212 |
|
|
* FIXME: check if sk_receive_queue is full, schedule DATA_DROPPED
|
| 213 |
|
|
* option if it is.
|
| 214 |
|
|
*/
|
| 215 |
|
|
__skb_pull(skb, dh->dccph_doff * 4);
|
| 216 |
|
|
__skb_queue_tail(&sk->sk_receive_queue, skb);
|
| 217 |
|
|
skb_set_owner_r(skb, sk);
|
| 218 |
|
|
sk->sk_data_ready(sk, 0);
|
| 219 |
|
|
return 0;
|
| 220 |
|
|
case DCCP_PKT_ACK:
|
| 221 |
|
|
goto discard;
|
| 222 |
|
|
case DCCP_PKT_RESET:
|
| 223 |
|
|
/*
|
| 224 |
|
|
* Step 9: Process Reset
|
| 225 |
|
|
* If P.type == Reset,
|
| 226 |
|
|
* Tear down connection
|
| 227 |
|
|
* S.state := TIMEWAIT
|
| 228 |
|
|
* Set TIMEWAIT timer
|
| 229 |
|
|
* Drop packet and return
|
| 230 |
|
|
*/
|
| 231 |
|
|
dccp_rcv_reset(sk, skb);
|
| 232 |
|
|
return 0;
|
| 233 |
|
|
case DCCP_PKT_CLOSEREQ:
|
| 234 |
|
|
dccp_rcv_closereq(sk, skb);
|
| 235 |
|
|
goto discard;
|
| 236 |
|
|
case DCCP_PKT_CLOSE:
|
| 237 |
|
|
dccp_rcv_close(sk, skb);
|
| 238 |
|
|
return 0;
|
| 239 |
|
|
case DCCP_PKT_REQUEST:
|
| 240 |
|
|
/* Step 7
|
| 241 |
|
|
* or (S.is_server and P.type == Response)
|
| 242 |
|
|
* or (S.is_client and P.type == Request)
|
| 243 |
|
|
* or (S.state >= OPEN and P.type == Request
|
| 244 |
|
|
* and P.seqno >= S.OSR)
|
| 245 |
|
|
* or (S.state >= OPEN and P.type == Response
|
| 246 |
|
|
* and P.seqno >= S.OSR)
|
| 247 |
|
|
* or (S.state == RESPOND and P.type == Data),
|
| 248 |
|
|
* Send Sync packet acknowledging P.seqno
|
| 249 |
|
|
* Drop packet and return
|
| 250 |
|
|
*/
|
| 251 |
|
|
if (dp->dccps_role != DCCP_ROLE_LISTEN)
|
| 252 |
|
|
goto send_sync;
|
| 253 |
|
|
goto check_seq;
|
| 254 |
|
|
case DCCP_PKT_RESPONSE:
|
| 255 |
|
|
if (dp->dccps_role != DCCP_ROLE_CLIENT)
|
| 256 |
|
|
goto send_sync;
|
| 257 |
|
|
check_seq:
|
| 258 |
|
|
if (dccp_delta_seqno(dp->dccps_osr,
|
| 259 |
|
|
DCCP_SKB_CB(skb)->dccpd_seq) >= 0) {
|
| 260 |
|
|
send_sync:
|
| 261 |
|
|
dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
|
| 262 |
|
|
DCCP_PKT_SYNC);
|
| 263 |
|
|
}
|
| 264 |
|
|
break;
|
| 265 |
|
|
case DCCP_PKT_SYNC:
|
| 266 |
|
|
dccp_send_sync(sk, DCCP_SKB_CB(skb)->dccpd_seq,
|
| 267 |
|
|
DCCP_PKT_SYNCACK);
|
| 268 |
|
|
/*
|
| 269 |
|
|
* From RFC 4340, sec. 5.7
|
| 270 |
|
|
*
|
| 271 |
|
|
* As with DCCP-Ack packets, DCCP-Sync and DCCP-SyncAck packets
|
| 272 |
|
|
* MAY have non-zero-length application data areas, whose
|
| 273 |
|
|
* contents receivers MUST ignore.
|
| 274 |
|
|
*/
|
| 275 |
|
|
goto discard;
|
| 276 |
|
|
}
|
| 277 |
|
|
|
| 278 |
|
|
DCCP_INC_STATS_BH(DCCP_MIB_INERRS);
|
| 279 |
|
|
discard:
|
| 280 |
|
|
__kfree_skb(skb);
|
| 281 |
|
|
return 0;
|
| 282 |
|
|
}
|
| 283 |
|
|
|
| 284 |
|
|
int dccp_rcv_established(struct sock *sk, struct sk_buff *skb,
|
| 285 |
|
|
const struct dccp_hdr *dh, const unsigned len)
|
| 286 |
|
|
{
|
| 287 |
|
|
struct dccp_sock *dp = dccp_sk(sk);
|
| 288 |
|
|
|
| 289 |
|
|
if (dccp_check_seqno(sk, skb))
|
| 290 |
|
|
goto discard;
|
| 291 |
|
|
|
| 292 |
|
|
if (dccp_parse_options(sk, skb))
|
| 293 |
|
|
goto discard;
|
| 294 |
|
|
|
| 295 |
|
|
if (DCCP_SKB_CB(skb)->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
|
| 296 |
|
|
dccp_event_ack_recv(sk, skb);
|
| 297 |
|
|
|
| 298 |
|
|
if (dccp_msk(sk)->dccpms_send_ack_vector &&
|
| 299 |
|
|
dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
|
| 300 |
|
|
DCCP_SKB_CB(skb)->dccpd_seq,
|
| 301 |
|
|
DCCP_ACKVEC_STATE_RECEIVED))
|
| 302 |
|
|
goto discard;
|
| 303 |
|
|
|
| 304 |
|
|
ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
|
| 305 |
|
|
ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
|
| 306 |
|
|
|
| 307 |
|
|
return __dccp_rcv_established(sk, skb, dh, len);
|
| 308 |
|
|
discard:
|
| 309 |
|
|
__kfree_skb(skb);
|
| 310 |
|
|
return 0;
|
| 311 |
|
|
}
|
| 312 |
|
|
|
| 313 |
|
|
EXPORT_SYMBOL_GPL(dccp_rcv_established);
|
| 314 |
|
|
|
| 315 |
|
|
static int dccp_rcv_request_sent_state_process(struct sock *sk,
|
| 316 |
|
|
struct sk_buff *skb,
|
| 317 |
|
|
const struct dccp_hdr *dh,
|
| 318 |
|
|
const unsigned len)
|
| 319 |
|
|
{
|
| 320 |
|
|
/*
|
| 321 |
|
|
* Step 4: Prepare sequence numbers in REQUEST
|
| 322 |
|
|
* If S.state == REQUEST,
|
| 323 |
|
|
* If (P.type == Response or P.type == Reset)
|
| 324 |
|
|
* and S.AWL <= P.ackno <= S.AWH,
|
| 325 |
|
|
* / * Set sequence number variables corresponding to the
|
| 326 |
|
|
* other endpoint, so P will pass the tests in Step 6 * /
|
| 327 |
|
|
* Set S.GSR, S.ISR, S.SWL, S.SWH
|
| 328 |
|
|
* / * Response processing continues in Step 10; Reset
|
| 329 |
|
|
* processing continues in Step 9 * /
|
| 330 |
|
|
*/
|
| 331 |
|
|
if (dh->dccph_type == DCCP_PKT_RESPONSE) {
|
| 332 |
|
|
const struct inet_connection_sock *icsk = inet_csk(sk);
|
| 333 |
|
|
struct dccp_sock *dp = dccp_sk(sk);
|
| 334 |
|
|
long tstamp = dccp_timestamp();
|
| 335 |
|
|
|
| 336 |
|
|
/* Stop the REQUEST timer */
|
| 337 |
|
|
inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
|
| 338 |
|
|
BUG_TRAP(sk->sk_send_head != NULL);
|
| 339 |
|
|
__kfree_skb(sk->sk_send_head);
|
| 340 |
|
|
sk->sk_send_head = NULL;
|
| 341 |
|
|
|
| 342 |
|
|
if (!between48(DCCP_SKB_CB(skb)->dccpd_ack_seq,
|
| 343 |
|
|
dp->dccps_awl, dp->dccps_awh)) {
|
| 344 |
|
|
dccp_pr_debug("invalid ackno: S.AWL=%llu, "
|
| 345 |
|
|
"P.ackno=%llu, S.AWH=%llu \n",
|
| 346 |
|
|
(unsigned long long)dp->dccps_awl,
|
| 347 |
|
|
(unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
|
| 348 |
|
|
(unsigned long long)dp->dccps_awh);
|
| 349 |
|
|
goto out_invalid_packet;
|
| 350 |
|
|
}
|
| 351 |
|
|
|
| 352 |
|
|
if (dccp_parse_options(sk, skb))
|
| 353 |
|
|
goto out_invalid_packet;
|
| 354 |
|
|
|
| 355 |
|
|
/* Obtain usec RTT sample from SYN exchange (used by CCID 3) */
|
| 356 |
|
|
if (likely(dp->dccps_options_received.dccpor_timestamp_echo))
|
| 357 |
|
|
dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp -
|
| 358 |
|
|
dp->dccps_options_received.dccpor_timestamp_echo));
|
| 359 |
|
|
|
| 360 |
|
|
if (dccp_msk(sk)->dccpms_send_ack_vector &&
|
| 361 |
|
|
dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
|
| 362 |
|
|
DCCP_SKB_CB(skb)->dccpd_seq,
|
| 363 |
|
|
DCCP_ACKVEC_STATE_RECEIVED))
|
| 364 |
|
|
goto out_invalid_packet; /* FIXME: change error code */
|
| 365 |
|
|
|
| 366 |
|
|
dp->dccps_isr = DCCP_SKB_CB(skb)->dccpd_seq;
|
| 367 |
|
|
dccp_update_gsr(sk, dp->dccps_isr);
|
| 368 |
|
|
/*
|
| 369 |
|
|
* SWL and AWL are initially adjusted so that they are not less than
|
| 370 |
|
|
* the initial Sequence Numbers received and sent, respectively:
|
| 371 |
|
|
* SWL := max(GSR + 1 - floor(W/4), ISR),
|
| 372 |
|
|
* AWL := max(GSS - W' + 1, ISS).
|
| 373 |
|
|
* These adjustments MUST be applied only at the beginning of the
|
| 374 |
|
|
* connection.
|
| 375 |
|
|
*
|
| 376 |
|
|
* AWL was adjusted in dccp_v4_connect -acme
|
| 377 |
|
|
*/
|
| 378 |
|
|
dccp_set_seqno(&dp->dccps_swl,
|
| 379 |
|
|
max48(dp->dccps_swl, dp->dccps_isr));
|
| 380 |
|
|
|
| 381 |
|
|
dccp_sync_mss(sk, icsk->icsk_pmtu_cookie);
|
| 382 |
|
|
|
| 383 |
|
|
/*
|
| 384 |
|
|
* Step 10: Process REQUEST state (second part)
|
| 385 |
|
|
* If S.state == REQUEST,
|
| 386 |
|
|
* / * If we get here, P is a valid Response from the
|
| 387 |
|
|
* server (see Step 4), and we should move to
|
| 388 |
|
|
* PARTOPEN state. PARTOPEN means send an Ack,
|
| 389 |
|
|
* don't send Data packets, retransmit Acks
|
| 390 |
|
|
* periodically, and always include any Init Cookie
|
| 391 |
|
|
* from the Response * /
|
| 392 |
|
|
* S.state := PARTOPEN
|
| 393 |
|
|
* Set PARTOPEN timer
|
| 394 |
|
|
* Continue with S.state == PARTOPEN
|
| 395 |
|
|
* / * Step 12 will send the Ack completing the
|
| 396 |
|
|
* three-way handshake * /
|
| 397 |
|
|
*/
|
| 398 |
|
|
dccp_set_state(sk, DCCP_PARTOPEN);
|
| 399 |
|
|
|
| 400 |
|
|
/* Make sure socket is routed, for correct metrics. */
|
| 401 |
|
|
icsk->icsk_af_ops->rebuild_header(sk);
|
| 402 |
|
|
|
| 403 |
|
|
if (!sock_flag(sk, SOCK_DEAD)) {
|
| 404 |
|
|
sk->sk_state_change(sk);
|
| 405 |
|
|
sk_wake_async(sk, 0, POLL_OUT);
|
| 406 |
|
|
}
|
| 407 |
|
|
|
| 408 |
|
|
if (sk->sk_write_pending || icsk->icsk_ack.pingpong ||
|
| 409 |
|
|
icsk->icsk_accept_queue.rskq_defer_accept) {
|
| 410 |
|
|
/* Save one ACK. Data will be ready after
|
| 411 |
|
|
* several ticks, if write_pending is set.
|
| 412 |
|
|
*
|
| 413 |
|
|
* It may be deleted, but with this feature tcpdumps
|
| 414 |
|
|
* look so _wonderfully_ clever, that I was not able
|
| 415 |
|
|
* to stand against the temptation 8) --ANK
|
| 416 |
|
|
*/
|
| 417 |
|
|
/*
|
| 418 |
|
|
* OK, in DCCP we can as well do a similar trick, its
|
| 419 |
|
|
* even in the draft, but there is no need for us to
|
| 420 |
|
|
* schedule an ack here, as dccp_sendmsg does this for
|
| 421 |
|
|
* us, also stated in the draft. -acme
|
| 422 |
|
|
*/
|
| 423 |
|
|
__kfree_skb(skb);
|
| 424 |
|
|
return 0;
|
| 425 |
|
|
}
|
| 426 |
|
|
dccp_send_ack(sk);
|
| 427 |
|
|
return -1;
|
| 428 |
|
|
}
|
| 429 |
|
|
|
| 430 |
|
|
out_invalid_packet:
|
| 431 |
|
|
/* dccp_v4_do_rcv will send a reset */
|
| 432 |
|
|
DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_PACKET_ERROR;
|
| 433 |
|
|
return 1;
|
| 434 |
|
|
}
|
| 435 |
|
|
|
| 436 |
|
|
static int dccp_rcv_respond_partopen_state_process(struct sock *sk,
|
| 437 |
|
|
struct sk_buff *skb,
|
| 438 |
|
|
const struct dccp_hdr *dh,
|
| 439 |
|
|
const unsigned len)
|
| 440 |
|
|
{
|
| 441 |
|
|
int queued = 0;
|
| 442 |
|
|
|
| 443 |
|
|
switch (dh->dccph_type) {
|
| 444 |
|
|
case DCCP_PKT_RESET:
|
| 445 |
|
|
inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
|
| 446 |
|
|
break;
|
| 447 |
|
|
case DCCP_PKT_DATA:
|
| 448 |
|
|
if (sk->sk_state == DCCP_RESPOND)
|
| 449 |
|
|
break;
|
| 450 |
|
|
case DCCP_PKT_DATAACK:
|
| 451 |
|
|
case DCCP_PKT_ACK:
|
| 452 |
|
|
/*
|
| 453 |
|
|
* FIXME: we should be reseting the PARTOPEN (DELACK) timer
|
| 454 |
|
|
* here but only if we haven't used the DELACK timer for
|
| 455 |
|
|
* something else, like sending a delayed ack for a TIMESTAMP
|
| 456 |
|
|
* echo, etc, for now were not clearing it, sending an extra
|
| 457 |
|
|
* ACK when there is nothing else to do in DELACK is not a big
|
| 458 |
|
|
* deal after all.
|
| 459 |
|
|
*/
|
| 460 |
|
|
|
| 461 |
|
|
/* Stop the PARTOPEN timer */
|
| 462 |
|
|
if (sk->sk_state == DCCP_PARTOPEN)
|
| 463 |
|
|
inet_csk_clear_xmit_timer(sk, ICSK_TIME_DACK);
|
| 464 |
|
|
|
| 465 |
|
|
dccp_sk(sk)->dccps_osr = DCCP_SKB_CB(skb)->dccpd_seq;
|
| 466 |
|
|
dccp_set_state(sk, DCCP_OPEN);
|
| 467 |
|
|
|
| 468 |
|
|
if (dh->dccph_type == DCCP_PKT_DATAACK ||
|
| 469 |
|
|
dh->dccph_type == DCCP_PKT_DATA) {
|
| 470 |
|
|
__dccp_rcv_established(sk, skb, dh, len);
|
| 471 |
|
|
queued = 1; /* packet was queued
|
| 472 |
|
|
(by __dccp_rcv_established) */
|
| 473 |
|
|
}
|
| 474 |
|
|
break;
|
| 475 |
|
|
}
|
| 476 |
|
|
|
| 477 |
|
|
return queued;
|
| 478 |
|
|
}
|
| 479 |
|
|
|
| 480 |
|
|
int dccp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
|
| 481 |
|
|
struct dccp_hdr *dh, unsigned len)
|
| 482 |
|
|
{
|
| 483 |
|
|
struct dccp_sock *dp = dccp_sk(sk);
|
| 484 |
|
|
struct dccp_skb_cb *dcb = DCCP_SKB_CB(skb);
|
| 485 |
|
|
const int old_state = sk->sk_state;
|
| 486 |
|
|
int queued = 0;
|
| 487 |
|
|
|
| 488 |
|
|
/*
|
| 489 |
|
|
* Step 3: Process LISTEN state
|
| 490 |
|
|
*
|
| 491 |
|
|
* If S.state == LISTEN,
|
| 492 |
|
|
* If P.type == Request or P contains a valid Init Cookie option,
|
| 493 |
|
|
* (* Must scan the packet's options to check for Init
|
| 494 |
|
|
* Cookies. Only Init Cookies are processed here,
|
| 495 |
|
|
* however; other options are processed in Step 8. This
|
| 496 |
|
|
* scan need only be performed if the endpoint uses Init
|
| 497 |
|
|
* Cookies *)
|
| 498 |
|
|
* (* Generate a new socket and switch to that socket *)
|
| 499 |
|
|
* Set S := new socket for this port pair
|
| 500 |
|
|
* S.state = RESPOND
|
| 501 |
|
|
* Choose S.ISS (initial seqno) or set from Init Cookies
|
| 502 |
|
|
* Initialize S.GAR := S.ISS
|
| 503 |
|
|
* Set S.ISR, S.GSR, S.SWL, S.SWH from packet or Init
|
| 504 |
|
|
* Cookies Continue with S.state == RESPOND
|
| 505 |
|
|
* (* A Response packet will be generated in Step 11 *)
|
| 506 |
|
|
* Otherwise,
|
| 507 |
|
|
* Generate Reset(No Connection) unless P.type == Reset
|
| 508 |
|
|
* Drop packet and return
|
| 509 |
|
|
*/
|
| 510 |
|
|
if (sk->sk_state == DCCP_LISTEN) {
|
| 511 |
|
|
if (dh->dccph_type == DCCP_PKT_REQUEST) {
|
| 512 |
|
|
if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
|
| 513 |
|
|
skb) < 0)
|
| 514 |
|
|
return 1;
|
| 515 |
|
|
|
| 516 |
|
|
/* FIXME: do congestion control initialization */
|
| 517 |
|
|
goto discard;
|
| 518 |
|
|
}
|
| 519 |
|
|
if (dh->dccph_type == DCCP_PKT_RESET)
|
| 520 |
|
|
goto discard;
|
| 521 |
|
|
|
| 522 |
|
|
/* Caller (dccp_v4_do_rcv) will send Reset */
|
| 523 |
|
|
dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
|
| 524 |
|
|
return 1;
|
| 525 |
|
|
}
|
| 526 |
|
|
|
| 527 |
|
|
if (sk->sk_state != DCCP_REQUESTING) {
|
| 528 |
|
|
if (dccp_check_seqno(sk, skb))
|
| 529 |
|
|
goto discard;
|
| 530 |
|
|
|
| 531 |
|
|
/*
|
| 532 |
|
|
* Step 8: Process options and mark acknowledgeable
|
| 533 |
|
|
*/
|
| 534 |
|
|
if (dccp_parse_options(sk, skb))
|
| 535 |
|
|
goto discard;
|
| 536 |
|
|
|
| 537 |
|
|
if (dcb->dccpd_ack_seq != DCCP_PKT_WITHOUT_ACK_SEQ)
|
| 538 |
|
|
dccp_event_ack_recv(sk, skb);
|
| 539 |
|
|
|
| 540 |
|
|
if (dccp_msk(sk)->dccpms_send_ack_vector &&
|
| 541 |
|
|
dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
|
| 542 |
|
|
DCCP_SKB_CB(skb)->dccpd_seq,
|
| 543 |
|
|
DCCP_ACKVEC_STATE_RECEIVED))
|
| 544 |
|
|
goto discard;
|
| 545 |
|
|
|
| 546 |
|
|
ccid_hc_rx_packet_recv(dp->dccps_hc_rx_ccid, sk, skb);
|
| 547 |
|
|
ccid_hc_tx_packet_recv(dp->dccps_hc_tx_ccid, sk, skb);
|
| 548 |
|
|
}
|
| 549 |
|
|
|
| 550 |
|
|
/*
|
| 551 |
|
|
* Step 9: Process Reset
|
| 552 |
|
|
* If P.type == Reset,
|
| 553 |
|
|
* Tear down connection
|
| 554 |
|
|
* S.state := TIMEWAIT
|
| 555 |
|
|
* Set TIMEWAIT timer
|
| 556 |
|
|
* Drop packet and return
|
| 557 |
|
|
*/
|
| 558 |
|
|
if (dh->dccph_type == DCCP_PKT_RESET) {
|
| 559 |
|
|
dccp_rcv_reset(sk, skb);
|
| 560 |
|
|
return 0;
|
| 561 |
|
|
/*
|
| 562 |
|
|
* Step 7: Check for unexpected packet types
|
| 563 |
|
|
* If (S.is_server and P.type == CloseReq)
|
| 564 |
|
|
* or (S.is_server and P.type == Response)
|
| 565 |
|
|
* or (S.is_client and P.type == Request)
|
| 566 |
|
|
* or (S.state == RESPOND and P.type == Data),
|
| 567 |
|
|
* Send Sync packet acknowledging P.seqno
|
| 568 |
|
|
* Drop packet and return
|
| 569 |
|
|
*/
|
| 570 |
|
|
} else if ((dp->dccps_role != DCCP_ROLE_CLIENT &&
|
| 571 |
|
|
(dh->dccph_type == DCCP_PKT_RESPONSE ||
|
| 572 |
|
|
dh->dccph_type == DCCP_PKT_CLOSEREQ)) ||
|
| 573 |
|
|
(dp->dccps_role == DCCP_ROLE_CLIENT &&
|
| 574 |
|
|
dh->dccph_type == DCCP_PKT_REQUEST) ||
|
| 575 |
|
|
(sk->sk_state == DCCP_RESPOND &&
|
| 576 |
|
|
dh->dccph_type == DCCP_PKT_DATA)) {
|
| 577 |
|
|
dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNC);
|
| 578 |
|
|
goto discard;
|
| 579 |
|
|
} else if (dh->dccph_type == DCCP_PKT_CLOSEREQ) {
|
| 580 |
|
|
dccp_rcv_closereq(sk, skb);
|
| 581 |
|
|
goto discard;
|
| 582 |
|
|
} else if (dh->dccph_type == DCCP_PKT_CLOSE) {
|
| 583 |
|
|
dccp_rcv_close(sk, skb);
|
| 584 |
|
|
return 0;
|
| 585 |
|
|
}
|
| 586 |
|
|
|
| 587 |
|
|
switch (sk->sk_state) {
|
| 588 |
|
|
case DCCP_CLOSED:
|
| 589 |
|
|
dcb->dccpd_reset_code = DCCP_RESET_CODE_NO_CONNECTION;
|
| 590 |
|
|
return 1;
|
| 591 |
|
|
|
| 592 |
|
|
case DCCP_REQUESTING:
|
| 593 |
|
|
/* FIXME: do congestion control initialization */
|
| 594 |
|
|
|
| 595 |
|
|
queued = dccp_rcv_request_sent_state_process(sk, skb, dh, len);
|
| 596 |
|
|
if (queued >= 0)
|
| 597 |
|
|
return queued;
|
| 598 |
|
|
|
| 599 |
|
|
__kfree_skb(skb);
|
| 600 |
|
|
return 0;
|
| 601 |
|
|
|
| 602 |
|
|
case DCCP_RESPOND:
|
| 603 |
|
|
case DCCP_PARTOPEN:
|
| 604 |
|
|
queued = dccp_rcv_respond_partopen_state_process(sk, skb,
|
| 605 |
|
|
dh, len);
|
| 606 |
|
|
break;
|
| 607 |
|
|
}
|
| 608 |
|
|
|
| 609 |
|
|
if (dh->dccph_type == DCCP_PKT_ACK ||
|
| 610 |
|
|
dh->dccph_type == DCCP_PKT_DATAACK) {
|
| 611 |
|
|
switch (old_state) {
|
| 612 |
|
|
case DCCP_PARTOPEN:
|
| 613 |
|
|
sk->sk_state_change(sk);
|
| 614 |
|
|
sk_wake_async(sk, 0, POLL_OUT);
|
| 615 |
|
|
break;
|
| 616 |
|
|
}
|
| 617 |
|
|
} else if (unlikely(dh->dccph_type == DCCP_PKT_SYNC)) {
|
| 618 |
|
|
dccp_send_sync(sk, dcb->dccpd_seq, DCCP_PKT_SYNCACK);
|
| 619 |
|
|
goto discard;
|
| 620 |
|
|
}
|
| 621 |
|
|
|
| 622 |
|
|
if (!queued) {
|
| 623 |
|
|
discard:
|
| 624 |
|
|
__kfree_skb(skb);
|
| 625 |
|
|
}
|
| 626 |
|
|
return 0;
|
| 627 |
|
|
}
|
| 628 |
|
|
|
| 629 |
|
|
EXPORT_SYMBOL_GPL(dccp_rcv_state_process);
|
| 630 |
|
|
|
| 631 |
|
|
/**
|
| 632 |
|
|
* dccp_sample_rtt - Validate and finalise computation of RTT sample
|
| 633 |
|
|
* @delta: number of microseconds between packet and acknowledgment
|
| 634 |
|
|
* The routine is kept generic to work in different contexts. It should be
|
| 635 |
|
|
* called immediately when the ACK used for the RTT sample arrives.
|
| 636 |
|
|
*/
|
| 637 |
|
|
u32 dccp_sample_rtt(struct sock *sk, long delta)
|
| 638 |
|
|
{
|
| 639 |
|
|
/* dccpor_elapsed_time is either zeroed out or set and > 0 */
|
| 640 |
|
|
delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10;
|
| 641 |
|
|
|
| 642 |
|
|
if (unlikely(delta <= 0)) {
|
| 643 |
|
|
DCCP_WARN("unusable RTT sample %ld, using min\n", delta);
|
| 644 |
|
|
return DCCP_SANE_RTT_MIN;
|
| 645 |
|
|
}
|
| 646 |
|
|
if (unlikely(delta > DCCP_SANE_RTT_MAX)) {
|
| 647 |
|
|
DCCP_WARN("RTT sample %ld too large, using max\n", delta);
|
| 648 |
|
|
return DCCP_SANE_RTT_MAX;
|
| 649 |
|
|
}
|
| 650 |
|
|
|
| 651 |
|
|
return delta;
|
| 652 |
|
|
}
|
| 653 |
|
|
|
| 654 |
|
|
EXPORT_SYMBOL_GPL(dccp_sample_rtt);
|
