268 lines
7.0 KiB
C
268 lines
7.0 KiB
C
/*
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* net/dccp/timer.c
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*
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* An implementation of the DCCP protocol
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* Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/config.h>
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#include <linux/dccp.h>
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#include <linux/skbuff.h>
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#include "dccp.h"
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static void dccp_write_timer(unsigned long data);
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static void dccp_keepalive_timer(unsigned long data);
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static void dccp_delack_timer(unsigned long data);
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void dccp_init_xmit_timers(struct sock *sk)
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{
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inet_csk_init_xmit_timers(sk, &dccp_write_timer, &dccp_delack_timer,
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&dccp_keepalive_timer);
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}
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static void dccp_write_err(struct sock *sk)
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{
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sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT;
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sk->sk_error_report(sk);
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dccp_send_reset(sk, DCCP_RESET_CODE_ABORTED);
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dccp_done(sk);
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DCCP_INC_STATS_BH(DCCP_MIB_ABORTONTIMEOUT);
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}
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/* A write timeout has occurred. Process the after effects. */
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static int dccp_write_timeout(struct sock *sk)
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{
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const struct inet_connection_sock *icsk = inet_csk(sk);
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int retry_until;
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if (sk->sk_state == DCCP_REQUESTING || sk->sk_state == DCCP_PARTOPEN) {
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if (icsk->icsk_retransmits != 0)
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dst_negative_advice(&sk->sk_dst_cache);
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retry_until = icsk->icsk_syn_retries ? :
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/* FIXME! */ 3 /* FIXME! sysctl_tcp_syn_retries */;
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} else {
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if (icsk->icsk_retransmits >=
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/* FIXME! sysctl_tcp_retries1 */ 5 /* FIXME! */) {
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/* NOTE. draft-ietf-tcpimpl-pmtud-01.txt requires pmtu
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black hole detection. :-(
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It is place to make it. It is not made. I do not want
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to make it. It is disguisting. It does not work in any
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case. Let me to cite the same draft, which requires for
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us to implement this:
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"The one security concern raised by this memo is that ICMP black holes
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are often caused by over-zealous security administrators who block
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all ICMP messages. It is vitally important that those who design and
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deploy security systems understand the impact of strict filtering on
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upper-layer protocols. The safest web site in the world is worthless
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if most TCP implementations cannot transfer data from it. It would
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be far nicer to have all of the black holes fixed rather than fixing
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all of the TCP implementations."
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Golden words :-).
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*/
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dst_negative_advice(&sk->sk_dst_cache);
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}
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retry_until = /* FIXME! */ 15 /* FIXME! sysctl_tcp_retries2 */;
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/*
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* FIXME: see tcp_write_timout and tcp_out_of_resources
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*/
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}
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if (icsk->icsk_retransmits >= retry_until) {
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/* Has it gone just too far? */
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dccp_write_err(sk);
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return 1;
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}
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return 0;
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}
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/* This is the same as tcp_delack_timer, sans prequeue & mem_reclaim stuff */
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static void dccp_delack_timer(unsigned long data)
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{
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struct sock *sk = (struct sock *)data;
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struct inet_connection_sock *icsk = inet_csk(sk);
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bh_lock_sock(sk);
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if (sock_owned_by_user(sk)) {
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/* Try again later. */
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icsk->icsk_ack.blocked = 1;
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NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKLOCKED);
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sk_reset_timer(sk, &icsk->icsk_delack_timer,
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jiffies + TCP_DELACK_MIN);
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goto out;
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}
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if (sk->sk_state == DCCP_CLOSED ||
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!(icsk->icsk_ack.pending & ICSK_ACK_TIMER))
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goto out;
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if (time_after(icsk->icsk_ack.timeout, jiffies)) {
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sk_reset_timer(sk, &icsk->icsk_delack_timer,
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icsk->icsk_ack.timeout);
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goto out;
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}
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icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER;
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if (inet_csk_ack_scheduled(sk)) {
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if (!icsk->icsk_ack.pingpong) {
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/* Delayed ACK missed: inflate ATO. */
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icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1,
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icsk->icsk_rto);
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} else {
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/* Delayed ACK missed: leave pingpong mode and
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* deflate ATO.
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*/
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icsk->icsk_ack.pingpong = 0;
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icsk->icsk_ack.ato = TCP_ATO_MIN;
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}
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dccp_send_ack(sk);
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NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKS);
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}
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out:
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bh_unlock_sock(sk);
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sock_put(sk);
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}
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/*
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* The DCCP retransmit timer.
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*/
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static void dccp_retransmit_timer(struct sock *sk)
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{
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struct inet_connection_sock *icsk = inet_csk(sk);
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/* retransmit timer is used for feature negotiation throughout
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* connection. In this case, no packet is re-transmitted, but rather an
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* ack is generated and pending changes are splaced into its options.
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*/
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if (sk->sk_send_head == NULL) {
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dccp_pr_debug("feat negotiation retransmit timeout %p\n", sk);
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if (sk->sk_state == DCCP_OPEN)
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dccp_send_ack(sk);
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goto backoff;
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}
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/*
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* sk->sk_send_head has to have one skb with
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* DCCP_SKB_CB(skb)->dccpd_type set to one of the retransmittable DCCP
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* packet types (REQUEST, RESPONSE, the ACK in the 3way handshake
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* (PARTOPEN timer), etc).
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*/
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BUG_TRAP(sk->sk_send_head != NULL);
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/*
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* More than than 4MSL (8 minutes) has passed, a RESET(aborted) was
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* sent, no need to retransmit, this sock is dead.
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*/
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if (dccp_write_timeout(sk))
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goto out;
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/*
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* We want to know the number of packets retransmitted, not the
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* total number of retransmissions of clones of original packets.
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*/
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if (icsk->icsk_retransmits == 0)
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DCCP_INC_STATS_BH(DCCP_MIB_TIMEOUTS);
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if (dccp_retransmit_skb(sk, sk->sk_send_head) < 0) {
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/*
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* Retransmission failed because of local congestion,
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* do not backoff.
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*/
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if (icsk->icsk_retransmits == 0)
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icsk->icsk_retransmits = 1;
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inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
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min(icsk->icsk_rto,
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TCP_RESOURCE_PROBE_INTERVAL),
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DCCP_RTO_MAX);
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goto out;
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}
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backoff:
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icsk->icsk_backoff++;
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icsk->icsk_retransmits++;
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icsk->icsk_rto = min(icsk->icsk_rto << 1, DCCP_RTO_MAX);
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inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto,
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DCCP_RTO_MAX);
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if (icsk->icsk_retransmits > 3 /* FIXME: sysctl_dccp_retries1 */)
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__sk_dst_reset(sk);
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out:;
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}
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static void dccp_write_timer(unsigned long data)
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{
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struct sock *sk = (struct sock *)data;
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struct inet_connection_sock *icsk = inet_csk(sk);
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int event = 0;
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bh_lock_sock(sk);
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if (sock_owned_by_user(sk)) {
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/* Try again later */
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sk_reset_timer(sk, &icsk->icsk_retransmit_timer,
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jiffies + (HZ / 20));
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goto out;
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}
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if (sk->sk_state == DCCP_CLOSED || !icsk->icsk_pending)
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goto out;
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if (time_after(icsk->icsk_timeout, jiffies)) {
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sk_reset_timer(sk, &icsk->icsk_retransmit_timer,
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icsk->icsk_timeout);
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goto out;
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}
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event = icsk->icsk_pending;
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icsk->icsk_pending = 0;
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switch (event) {
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case ICSK_TIME_RETRANS:
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dccp_retransmit_timer(sk);
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break;
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}
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out:
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bh_unlock_sock(sk);
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sock_put(sk);
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}
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/*
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* Timer for listening sockets
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*/
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static void dccp_response_timer(struct sock *sk)
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{
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inet_csk_reqsk_queue_prune(sk, TCP_SYNQ_INTERVAL, DCCP_TIMEOUT_INIT,
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DCCP_RTO_MAX);
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}
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static void dccp_keepalive_timer(unsigned long data)
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{
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struct sock *sk = (struct sock *)data;
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/* Only process if socket is not in use. */
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bh_lock_sock(sk);
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if (sock_owned_by_user(sk)) {
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/* Try again later. */
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inet_csk_reset_keepalive_timer(sk, HZ / 20);
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goto out;
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}
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if (sk->sk_state == DCCP_LISTEN) {
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dccp_response_timer(sk);
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goto out;
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}
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out:
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bh_unlock_sock(sk);
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sock_put(sk);
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}
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