| 1 |
62 |
marcus.erl |
/*
|
| 2 |
|
|
* INET An implementation of the TCP/IP protocol suite for the LINUX
|
| 3 |
|
|
* operating system. INET is implemented using the BSD Socket
|
| 4 |
|
|
* interface as the means of communication with the user level.
|
| 5 |
|
|
*
|
| 6 |
|
|
* Implementation of the Transmission Control Protocol(TCP).
|
| 7 |
|
|
*
|
| 8 |
|
|
* Version: $Id: tcp_timer.c,v 1.88 2002/02/01 22:01:04 davem Exp $
|
| 9 |
|
|
*
|
| 10 |
|
|
* Authors: Ross Biro
|
| 11 |
|
|
* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
|
| 12 |
|
|
* Mark Evans, <evansmp@uhura.aston.ac.uk>
|
| 13 |
|
|
* Corey Minyard <wf-rch!minyard@relay.EU.net>
|
| 14 |
|
|
* Florian La Roche, <flla@stud.uni-sb.de>
|
| 15 |
|
|
* Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
|
| 16 |
|
|
* Linus Torvalds, <torvalds@cs.helsinki.fi>
|
| 17 |
|
|
* Alan Cox, <gw4pts@gw4pts.ampr.org>
|
| 18 |
|
|
* Matthew Dillon, <dillon@apollo.west.oic.com>
|
| 19 |
|
|
* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
|
| 20 |
|
|
* Jorge Cwik, <jorge@laser.satlink.net>
|
| 21 |
|
|
*/
|
| 22 |
|
|
|
| 23 |
|
|
#include <linux/module.h>
|
| 24 |
|
|
#include <net/tcp.h>
|
| 25 |
|
|
|
| 26 |
|
|
int sysctl_tcp_syn_retries __read_mostly = TCP_SYN_RETRIES;
|
| 27 |
|
|
int sysctl_tcp_synack_retries __read_mostly = TCP_SYNACK_RETRIES;
|
| 28 |
|
|
int sysctl_tcp_keepalive_time __read_mostly = TCP_KEEPALIVE_TIME;
|
| 29 |
|
|
int sysctl_tcp_keepalive_probes __read_mostly = TCP_KEEPALIVE_PROBES;
|
| 30 |
|
|
int sysctl_tcp_keepalive_intvl __read_mostly = TCP_KEEPALIVE_INTVL;
|
| 31 |
|
|
int sysctl_tcp_retries1 __read_mostly = TCP_RETR1;
|
| 32 |
|
|
int sysctl_tcp_retries2 __read_mostly = TCP_RETR2;
|
| 33 |
|
|
int sysctl_tcp_orphan_retries __read_mostly;
|
| 34 |
|
|
|
| 35 |
|
|
static void tcp_write_timer(unsigned long);
|
| 36 |
|
|
static void tcp_delack_timer(unsigned long);
|
| 37 |
|
|
static void tcp_keepalive_timer (unsigned long data);
|
| 38 |
|
|
|
| 39 |
|
|
void tcp_init_xmit_timers(struct sock *sk)
|
| 40 |
|
|
{
|
| 41 |
|
|
inet_csk_init_xmit_timers(sk, &tcp_write_timer, &tcp_delack_timer,
|
| 42 |
|
|
&tcp_keepalive_timer);
|
| 43 |
|
|
}
|
| 44 |
|
|
|
| 45 |
|
|
EXPORT_SYMBOL(tcp_init_xmit_timers);
|
| 46 |
|
|
|
| 47 |
|
|
static void tcp_write_err(struct sock *sk)
|
| 48 |
|
|
{
|
| 49 |
|
|
sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT;
|
| 50 |
|
|
sk->sk_error_report(sk);
|
| 51 |
|
|
|
| 52 |
|
|
tcp_done(sk);
|
| 53 |
|
|
NET_INC_STATS_BH(LINUX_MIB_TCPABORTONTIMEOUT);
|
| 54 |
|
|
}
|
| 55 |
|
|
|
| 56 |
|
|
/* Do not allow orphaned sockets to eat all our resources.
|
| 57 |
|
|
* This is direct violation of TCP specs, but it is required
|
| 58 |
|
|
* to prevent DoS attacks. It is called when a retransmission timeout
|
| 59 |
|
|
* or zero probe timeout occurs on orphaned socket.
|
| 60 |
|
|
*
|
| 61 |
|
|
* Criteria is still not confirmed experimentally and may change.
|
| 62 |
|
|
* We kill the socket, if:
|
| 63 |
|
|
* 1. If number of orphaned sockets exceeds an administratively configured
|
| 64 |
|
|
* limit.
|
| 65 |
|
|
* 2. If we have strong memory pressure.
|
| 66 |
|
|
*/
|
| 67 |
|
|
static int tcp_out_of_resources(struct sock *sk, int do_reset)
|
| 68 |
|
|
{
|
| 69 |
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
| 70 |
|
|
int orphans = atomic_read(&tcp_orphan_count);
|
| 71 |
|
|
|
| 72 |
|
|
/* If peer does not open window for long time, or did not transmit
|
| 73 |
|
|
* anything for long time, penalize it. */
|
| 74 |
|
|
if ((s32)(tcp_time_stamp - tp->lsndtime) > 2*TCP_RTO_MAX || !do_reset)
|
| 75 |
|
|
orphans <<= 1;
|
| 76 |
|
|
|
| 77 |
|
|
/* If some dubious ICMP arrived, penalize even more. */
|
| 78 |
|
|
if (sk->sk_err_soft)
|
| 79 |
|
|
orphans <<= 1;
|
| 80 |
|
|
|
| 81 |
|
|
if (tcp_too_many_orphans(sk, orphans)) {
|
| 82 |
|
|
if (net_ratelimit())
|
| 83 |
|
|
printk(KERN_INFO "Out of socket memory\n");
|
| 84 |
|
|
|
| 85 |
|
|
/* Catch exceptional cases, when connection requires reset.
|
| 86 |
|
|
* 1. Last segment was sent recently. */
|
| 87 |
|
|
if ((s32)(tcp_time_stamp - tp->lsndtime) <= TCP_TIMEWAIT_LEN ||
|
| 88 |
|
|
/* 2. Window is closed. */
|
| 89 |
|
|
(!tp->snd_wnd && !tp->packets_out))
|
| 90 |
|
|
do_reset = 1;
|
| 91 |
|
|
if (do_reset)
|
| 92 |
|
|
tcp_send_active_reset(sk, GFP_ATOMIC);
|
| 93 |
|
|
tcp_done(sk);
|
| 94 |
|
|
NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY);
|
| 95 |
|
|
return 1;
|
| 96 |
|
|
}
|
| 97 |
|
|
return 0;
|
| 98 |
|
|
}
|
| 99 |
|
|
|
| 100 |
|
|
/* Calculate maximal number or retries on an orphaned socket. */
|
| 101 |
|
|
static int tcp_orphan_retries(struct sock *sk, int alive)
|
| 102 |
|
|
{
|
| 103 |
|
|
int retries = sysctl_tcp_orphan_retries; /* May be zero. */
|
| 104 |
|
|
|
| 105 |
|
|
/* We know from an ICMP that something is wrong. */
|
| 106 |
|
|
if (sk->sk_err_soft && !alive)
|
| 107 |
|
|
retries = 0;
|
| 108 |
|
|
|
| 109 |
|
|
/* However, if socket sent something recently, select some safe
|
| 110 |
|
|
* number of retries. 8 corresponds to >100 seconds with minimal
|
| 111 |
|
|
* RTO of 200msec. */
|
| 112 |
|
|
if (retries == 0 && alive)
|
| 113 |
|
|
retries = 8;
|
| 114 |
|
|
return retries;
|
| 115 |
|
|
}
|
| 116 |
|
|
|
| 117 |
|
|
/* A write timeout has occurred. Process the after effects. */
|
| 118 |
|
|
static int tcp_write_timeout(struct sock *sk)
|
| 119 |
|
|
{
|
| 120 |
|
|
struct inet_connection_sock *icsk = inet_csk(sk);
|
| 121 |
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
| 122 |
|
|
int retry_until;
|
| 123 |
|
|
int mss;
|
| 124 |
|
|
|
| 125 |
|
|
if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
|
| 126 |
|
|
if (icsk->icsk_retransmits)
|
| 127 |
|
|
dst_negative_advice(&sk->sk_dst_cache);
|
| 128 |
|
|
retry_until = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries;
|
| 129 |
|
|
} else {
|
| 130 |
|
|
if (icsk->icsk_retransmits >= sysctl_tcp_retries1) {
|
| 131 |
|
|
/* Black hole detection */
|
| 132 |
|
|
if (sysctl_tcp_mtu_probing) {
|
| 133 |
|
|
if (!icsk->icsk_mtup.enabled) {
|
| 134 |
|
|
icsk->icsk_mtup.enabled = 1;
|
| 135 |
|
|
tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
|
| 136 |
|
|
} else {
|
| 137 |
|
|
mss = min(sysctl_tcp_base_mss,
|
| 138 |
|
|
tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low)/2);
|
| 139 |
|
|
mss = max(mss, 68 - tp->tcp_header_len);
|
| 140 |
|
|
icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss);
|
| 141 |
|
|
tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
|
| 142 |
|
|
}
|
| 143 |
|
|
}
|
| 144 |
|
|
|
| 145 |
|
|
dst_negative_advice(&sk->sk_dst_cache);
|
| 146 |
|
|
}
|
| 147 |
|
|
|
| 148 |
|
|
retry_until = sysctl_tcp_retries2;
|
| 149 |
|
|
if (sock_flag(sk, SOCK_DEAD)) {
|
| 150 |
|
|
const int alive = (icsk->icsk_rto < TCP_RTO_MAX);
|
| 151 |
|
|
|
| 152 |
|
|
retry_until = tcp_orphan_retries(sk, alive);
|
| 153 |
|
|
|
| 154 |
|
|
if (tcp_out_of_resources(sk, alive || icsk->icsk_retransmits < retry_until))
|
| 155 |
|
|
return 1;
|
| 156 |
|
|
}
|
| 157 |
|
|
}
|
| 158 |
|
|
|
| 159 |
|
|
if (icsk->icsk_retransmits >= retry_until) {
|
| 160 |
|
|
/* Has it gone just too far? */
|
| 161 |
|
|
tcp_write_err(sk);
|
| 162 |
|
|
return 1;
|
| 163 |
|
|
}
|
| 164 |
|
|
return 0;
|
| 165 |
|
|
}
|
| 166 |
|
|
|
| 167 |
|
|
static void tcp_delack_timer(unsigned long data)
|
| 168 |
|
|
{
|
| 169 |
|
|
struct sock *sk = (struct sock*)data;
|
| 170 |
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
| 171 |
|
|
struct inet_connection_sock *icsk = inet_csk(sk);
|
| 172 |
|
|
|
| 173 |
|
|
bh_lock_sock(sk);
|
| 174 |
|
|
if (sock_owned_by_user(sk)) {
|
| 175 |
|
|
/* Try again later. */
|
| 176 |
|
|
icsk->icsk_ack.blocked = 1;
|
| 177 |
|
|
NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKLOCKED);
|
| 178 |
|
|
sk_reset_timer(sk, &icsk->icsk_delack_timer, jiffies + TCP_DELACK_MIN);
|
| 179 |
|
|
goto out_unlock;
|
| 180 |
|
|
}
|
| 181 |
|
|
|
| 182 |
|
|
sk_stream_mem_reclaim(sk);
|
| 183 |
|
|
|
| 184 |
|
|
if (sk->sk_state == TCP_CLOSE || !(icsk->icsk_ack.pending & ICSK_ACK_TIMER))
|
| 185 |
|
|
goto out;
|
| 186 |
|
|
|
| 187 |
|
|
if (time_after(icsk->icsk_ack.timeout, jiffies)) {
|
| 188 |
|
|
sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout);
|
| 189 |
|
|
goto out;
|
| 190 |
|
|
}
|
| 191 |
|
|
icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER;
|
| 192 |
|
|
|
| 193 |
|
|
if (!skb_queue_empty(&tp->ucopy.prequeue)) {
|
| 194 |
|
|
struct sk_buff *skb;
|
| 195 |
|
|
|
| 196 |
|
|
NET_INC_STATS_BH(LINUX_MIB_TCPSCHEDULERFAILED);
|
| 197 |
|
|
|
| 198 |
|
|
while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
|
| 199 |
|
|
sk->sk_backlog_rcv(sk, skb);
|
| 200 |
|
|
|
| 201 |
|
|
tp->ucopy.memory = 0;
|
| 202 |
|
|
}
|
| 203 |
|
|
|
| 204 |
|
|
if (inet_csk_ack_scheduled(sk)) {
|
| 205 |
|
|
if (!icsk->icsk_ack.pingpong) {
|
| 206 |
|
|
/* Delayed ACK missed: inflate ATO. */
|
| 207 |
|
|
icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1, icsk->icsk_rto);
|
| 208 |
|
|
} else {
|
| 209 |
|
|
/* Delayed ACK missed: leave pingpong mode and
|
| 210 |
|
|
* deflate ATO.
|
| 211 |
|
|
*/
|
| 212 |
|
|
icsk->icsk_ack.pingpong = 0;
|
| 213 |
|
|
icsk->icsk_ack.ato = TCP_ATO_MIN;
|
| 214 |
|
|
}
|
| 215 |
|
|
tcp_send_ack(sk);
|
| 216 |
|
|
NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKS);
|
| 217 |
|
|
}
|
| 218 |
|
|
TCP_CHECK_TIMER(sk);
|
| 219 |
|
|
|
| 220 |
|
|
out:
|
| 221 |
|
|
if (tcp_memory_pressure)
|
| 222 |
|
|
sk_stream_mem_reclaim(sk);
|
| 223 |
|
|
out_unlock:
|
| 224 |
|
|
bh_unlock_sock(sk);
|
| 225 |
|
|
sock_put(sk);
|
| 226 |
|
|
}
|
| 227 |
|
|
|
| 228 |
|
|
static void tcp_probe_timer(struct sock *sk)
|
| 229 |
|
|
{
|
| 230 |
|
|
struct inet_connection_sock *icsk = inet_csk(sk);
|
| 231 |
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
| 232 |
|
|
int max_probes;
|
| 233 |
|
|
|
| 234 |
|
|
if (tp->packets_out || !tcp_send_head(sk)) {
|
| 235 |
|
|
icsk->icsk_probes_out = 0;
|
| 236 |
|
|
return;
|
| 237 |
|
|
}
|
| 238 |
|
|
|
| 239 |
|
|
/* *WARNING* RFC 1122 forbids this
|
| 240 |
|
|
*
|
| 241 |
|
|
* It doesn't AFAIK, because we kill the retransmit timer -AK
|
| 242 |
|
|
*
|
| 243 |
|
|
* FIXME: We ought not to do it, Solaris 2.5 actually has fixing
|
| 244 |
|
|
* this behaviour in Solaris down as a bug fix. [AC]
|
| 245 |
|
|
*
|
| 246 |
|
|
* Let me to explain. icsk_probes_out is zeroed by incoming ACKs
|
| 247 |
|
|
* even if they advertise zero window. Hence, connection is killed only
|
| 248 |
|
|
* if we received no ACKs for normal connection timeout. It is not killed
|
| 249 |
|
|
* only because window stays zero for some time, window may be zero
|
| 250 |
|
|
* until armageddon and even later. We are in full accordance
|
| 251 |
|
|
* with RFCs, only probe timer combines both retransmission timeout
|
| 252 |
|
|
* and probe timeout in one bottle. --ANK
|
| 253 |
|
|
*/
|
| 254 |
|
|
max_probes = sysctl_tcp_retries2;
|
| 255 |
|
|
|
| 256 |
|
|
if (sock_flag(sk, SOCK_DEAD)) {
|
| 257 |
|
|
const int alive = ((icsk->icsk_rto << icsk->icsk_backoff) < TCP_RTO_MAX);
|
| 258 |
|
|
|
| 259 |
|
|
max_probes = tcp_orphan_retries(sk, alive);
|
| 260 |
|
|
|
| 261 |
|
|
if (tcp_out_of_resources(sk, alive || icsk->icsk_probes_out <= max_probes))
|
| 262 |
|
|
return;
|
| 263 |
|
|
}
|
| 264 |
|
|
|
| 265 |
|
|
if (icsk->icsk_probes_out > max_probes) {
|
| 266 |
|
|
tcp_write_err(sk);
|
| 267 |
|
|
} else {
|
| 268 |
|
|
/* Only send another probe if we didn't close things up. */
|
| 269 |
|
|
tcp_send_probe0(sk);
|
| 270 |
|
|
}
|
| 271 |
|
|
}
|
| 272 |
|
|
|
| 273 |
|
|
/*
|
| 274 |
|
|
* The TCP retransmit timer.
|
| 275 |
|
|
*/
|
| 276 |
|
|
|
| 277 |
|
|
static void tcp_retransmit_timer(struct sock *sk)
|
| 278 |
|
|
{
|
| 279 |
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
| 280 |
|
|
struct inet_connection_sock *icsk = inet_csk(sk);
|
| 281 |
|
|
|
| 282 |
|
|
if (!tp->packets_out)
|
| 283 |
|
|
goto out;
|
| 284 |
|
|
|
| 285 |
|
|
BUG_TRAP(!tcp_write_queue_empty(sk));
|
| 286 |
|
|
|
| 287 |
|
|
if (!tp->snd_wnd && !sock_flag(sk, SOCK_DEAD) &&
|
| 288 |
|
|
!((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))) {
|
| 289 |
|
|
/* Receiver dastardly shrinks window. Our retransmits
|
| 290 |
|
|
* become zero probes, but we should not timeout this
|
| 291 |
|
|
* connection. If the socket is an orphan, time it out,
|
| 292 |
|
|
* we cannot allow such beasts to hang infinitely.
|
| 293 |
|
|
*/
|
| 294 |
|
|
#ifdef TCP_DEBUG
|
| 295 |
|
|
if (1) {
|
| 296 |
|
|
struct inet_sock *inet = inet_sk(sk);
|
| 297 |
|
|
LIMIT_NETDEBUG(KERN_DEBUG "TCP: Treason uncloaked! Peer %u.%u.%u.%u:%u/%u shrinks window %u:%u. Repaired.\n",
|
| 298 |
|
|
NIPQUAD(inet->daddr), ntohs(inet->dport),
|
| 299 |
|
|
inet->num, tp->snd_una, tp->snd_nxt);
|
| 300 |
|
|
}
|
| 301 |
|
|
#endif
|
| 302 |
|
|
if (tcp_time_stamp - tp->rcv_tstamp > TCP_RTO_MAX) {
|
| 303 |
|
|
tcp_write_err(sk);
|
| 304 |
|
|
goto out;
|
| 305 |
|
|
}
|
| 306 |
|
|
tcp_enter_loss(sk, 0);
|
| 307 |
|
|
tcp_retransmit_skb(sk, tcp_write_queue_head(sk));
|
| 308 |
|
|
__sk_dst_reset(sk);
|
| 309 |
|
|
goto out_reset_timer;
|
| 310 |
|
|
}
|
| 311 |
|
|
|
| 312 |
|
|
if (tcp_write_timeout(sk))
|
| 313 |
|
|
goto out;
|
| 314 |
|
|
|
| 315 |
|
|
if (icsk->icsk_retransmits == 0) {
|
| 316 |
|
|
if (icsk->icsk_ca_state == TCP_CA_Disorder ||
|
| 317 |
|
|
icsk->icsk_ca_state == TCP_CA_Recovery) {
|
| 318 |
|
|
if (tcp_is_sack(tp)) {
|
| 319 |
|
|
if (icsk->icsk_ca_state == TCP_CA_Recovery)
|
| 320 |
|
|
NET_INC_STATS_BH(LINUX_MIB_TCPSACKRECOVERYFAIL);
|
| 321 |
|
|
else
|
| 322 |
|
|
NET_INC_STATS_BH(LINUX_MIB_TCPSACKFAILURES);
|
| 323 |
|
|
} else {
|
| 324 |
|
|
if (icsk->icsk_ca_state == TCP_CA_Recovery)
|
| 325 |
|
|
NET_INC_STATS_BH(LINUX_MIB_TCPRENORECOVERYFAIL);
|
| 326 |
|
|
else
|
| 327 |
|
|
NET_INC_STATS_BH(LINUX_MIB_TCPRENOFAILURES);
|
| 328 |
|
|
}
|
| 329 |
|
|
} else if (icsk->icsk_ca_state == TCP_CA_Loss) {
|
| 330 |
|
|
NET_INC_STATS_BH(LINUX_MIB_TCPLOSSFAILURES);
|
| 331 |
|
|
} else {
|
| 332 |
|
|
NET_INC_STATS_BH(LINUX_MIB_TCPTIMEOUTS);
|
| 333 |
|
|
}
|
| 334 |
|
|
}
|
| 335 |
|
|
|
| 336 |
|
|
if (tcp_use_frto(sk)) {
|
| 337 |
|
|
tcp_enter_frto(sk);
|
| 338 |
|
|
} else {
|
| 339 |
|
|
tcp_enter_loss(sk, 0);
|
| 340 |
|
|
}
|
| 341 |
|
|
|
| 342 |
|
|
if (tcp_retransmit_skb(sk, tcp_write_queue_head(sk)) > 0) {
|
| 343 |
|
|
/* Retransmission failed because of local congestion,
|
| 344 |
|
|
* do not backoff.
|
| 345 |
|
|
*/
|
| 346 |
|
|
if (!icsk->icsk_retransmits)
|
| 347 |
|
|
icsk->icsk_retransmits = 1;
|
| 348 |
|
|
inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS,
|
| 349 |
|
|
min(icsk->icsk_rto, TCP_RESOURCE_PROBE_INTERVAL),
|
| 350 |
|
|
TCP_RTO_MAX);
|
| 351 |
|
|
goto out;
|
| 352 |
|
|
}
|
| 353 |
|
|
|
| 354 |
|
|
/* Increase the timeout each time we retransmit. Note that
|
| 355 |
|
|
* we do not increase the rtt estimate. rto is initialized
|
| 356 |
|
|
* from rtt, but increases here. Jacobson (SIGCOMM 88) suggests
|
| 357 |
|
|
* that doubling rto each time is the least we can get away with.
|
| 358 |
|
|
* In KA9Q, Karn uses this for the first few times, and then
|
| 359 |
|
|
* goes to quadratic. netBSD doubles, but only goes up to *64,
|
| 360 |
|
|
* and clamps at 1 to 64 sec afterwards. Note that 120 sec is
|
| 361 |
|
|
* defined in the protocol as the maximum possible RTT. I guess
|
| 362 |
|
|
* we'll have to use something other than TCP to talk to the
|
| 363 |
|
|
* University of Mars.
|
| 364 |
|
|
*
|
| 365 |
|
|
* PAWS allows us longer timeouts and large windows, so once
|
| 366 |
|
|
* implemented ftp to mars will work nicely. We will have to fix
|
| 367 |
|
|
* the 120 second clamps though!
|
| 368 |
|
|
*/
|
| 369 |
|
|
icsk->icsk_backoff++;
|
| 370 |
|
|
icsk->icsk_retransmits++;
|
| 371 |
|
|
|
| 372 |
|
|
out_reset_timer:
|
| 373 |
|
|
icsk->icsk_rto = min(icsk->icsk_rto << 1, TCP_RTO_MAX);
|
| 374 |
|
|
inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto, TCP_RTO_MAX);
|
| 375 |
|
|
if (icsk->icsk_retransmits > sysctl_tcp_retries1)
|
| 376 |
|
|
__sk_dst_reset(sk);
|
| 377 |
|
|
|
| 378 |
|
|
out:;
|
| 379 |
|
|
}
|
| 380 |
|
|
|
| 381 |
|
|
static void tcp_write_timer(unsigned long data)
|
| 382 |
|
|
{
|
| 383 |
|
|
struct sock *sk = (struct sock*)data;
|
| 384 |
|
|
struct inet_connection_sock *icsk = inet_csk(sk);
|
| 385 |
|
|
int event;
|
| 386 |
|
|
|
| 387 |
|
|
bh_lock_sock(sk);
|
| 388 |
|
|
if (sock_owned_by_user(sk)) {
|
| 389 |
|
|
/* Try again later */
|
| 390 |
|
|
sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + (HZ / 20));
|
| 391 |
|
|
goto out_unlock;
|
| 392 |
|
|
}
|
| 393 |
|
|
|
| 394 |
|
|
if (sk->sk_state == TCP_CLOSE || !icsk->icsk_pending)
|
| 395 |
|
|
goto out;
|
| 396 |
|
|
|
| 397 |
|
|
if (time_after(icsk->icsk_timeout, jiffies)) {
|
| 398 |
|
|
sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout);
|
| 399 |
|
|
goto out;
|
| 400 |
|
|
}
|
| 401 |
|
|
|
| 402 |
|
|
event = icsk->icsk_pending;
|
| 403 |
|
|
icsk->icsk_pending = 0;
|
| 404 |
|
|
|
| 405 |
|
|
switch (event) {
|
| 406 |
|
|
case ICSK_TIME_RETRANS:
|
| 407 |
|
|
tcp_retransmit_timer(sk);
|
| 408 |
|
|
break;
|
| 409 |
|
|
case ICSK_TIME_PROBE0:
|
| 410 |
|
|
tcp_probe_timer(sk);
|
| 411 |
|
|
break;
|
| 412 |
|
|
}
|
| 413 |
|
|
TCP_CHECK_TIMER(sk);
|
| 414 |
|
|
|
| 415 |
|
|
out:
|
| 416 |
|
|
sk_stream_mem_reclaim(sk);
|
| 417 |
|
|
out_unlock:
|
| 418 |
|
|
bh_unlock_sock(sk);
|
| 419 |
|
|
sock_put(sk);
|
| 420 |
|
|
}
|
| 421 |
|
|
|
| 422 |
|
|
/*
|
| 423 |
|
|
* Timer for listening sockets
|
| 424 |
|
|
*/
|
| 425 |
|
|
|
| 426 |
|
|
static void tcp_synack_timer(struct sock *sk)
|
| 427 |
|
|
{
|
| 428 |
|
|
inet_csk_reqsk_queue_prune(sk, TCP_SYNQ_INTERVAL,
|
| 429 |
|
|
TCP_TIMEOUT_INIT, TCP_RTO_MAX);
|
| 430 |
|
|
}
|
| 431 |
|
|
|
| 432 |
|
|
void tcp_set_keepalive(struct sock *sk, int val)
|
| 433 |
|
|
{
|
| 434 |
|
|
if ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))
|
| 435 |
|
|
return;
|
| 436 |
|
|
|
| 437 |
|
|
if (val && !sock_flag(sk, SOCK_KEEPOPEN))
|
| 438 |
|
|
inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tcp_sk(sk)));
|
| 439 |
|
|
else if (!val)
|
| 440 |
|
|
inet_csk_delete_keepalive_timer(sk);
|
| 441 |
|
|
}
|
| 442 |
|
|
|
| 443 |
|
|
|
| 444 |
|
|
static void tcp_keepalive_timer (unsigned long data)
|
| 445 |
|
|
{
|
| 446 |
|
|
struct sock *sk = (struct sock *) data;
|
| 447 |
|
|
struct inet_connection_sock *icsk = inet_csk(sk);
|
| 448 |
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
| 449 |
|
|
__u32 elapsed;
|
| 450 |
|
|
|
| 451 |
|
|
/* Only process if socket is not in use. */
|
| 452 |
|
|
bh_lock_sock(sk);
|
| 453 |
|
|
if (sock_owned_by_user(sk)) {
|
| 454 |
|
|
/* Try again later. */
|
| 455 |
|
|
inet_csk_reset_keepalive_timer (sk, HZ/20);
|
| 456 |
|
|
goto out;
|
| 457 |
|
|
}
|
| 458 |
|
|
|
| 459 |
|
|
if (sk->sk_state == TCP_LISTEN) {
|
| 460 |
|
|
tcp_synack_timer(sk);
|
| 461 |
|
|
goto out;
|
| 462 |
|
|
}
|
| 463 |
|
|
|
| 464 |
|
|
if (sk->sk_state == TCP_FIN_WAIT2 && sock_flag(sk, SOCK_DEAD)) {
|
| 465 |
|
|
if (tp->linger2 >= 0) {
|
| 466 |
|
|
const int tmo = tcp_fin_time(sk) - TCP_TIMEWAIT_LEN;
|
| 467 |
|
|
|
| 468 |
|
|
if (tmo > 0) {
|
| 469 |
|
|
tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
|
| 470 |
|
|
goto out;
|
| 471 |
|
|
}
|
| 472 |
|
|
}
|
| 473 |
|
|
tcp_send_active_reset(sk, GFP_ATOMIC);
|
| 474 |
|
|
goto death;
|
| 475 |
|
|
}
|
| 476 |
|
|
|
| 477 |
|
|
if (!sock_flag(sk, SOCK_KEEPOPEN) || sk->sk_state == TCP_CLOSE)
|
| 478 |
|
|
goto out;
|
| 479 |
|
|
|
| 480 |
|
|
elapsed = keepalive_time_when(tp);
|
| 481 |
|
|
|
| 482 |
|
|
/* It is alive without keepalive 8) */
|
| 483 |
|
|
if (tp->packets_out || tcp_send_head(sk))
|
| 484 |
|
|
goto resched;
|
| 485 |
|
|
|
| 486 |
|
|
elapsed = tcp_time_stamp - tp->rcv_tstamp;
|
| 487 |
|
|
|
| 488 |
|
|
if (elapsed >= keepalive_time_when(tp)) {
|
| 489 |
|
|
if ((!tp->keepalive_probes && icsk->icsk_probes_out >= sysctl_tcp_keepalive_probes) ||
|
| 490 |
|
|
(tp->keepalive_probes && icsk->icsk_probes_out >= tp->keepalive_probes)) {
|
| 491 |
|
|
tcp_send_active_reset(sk, GFP_ATOMIC);
|
| 492 |
|
|
tcp_write_err(sk);
|
| 493 |
|
|
goto out;
|
| 494 |
|
|
}
|
| 495 |
|
|
if (tcp_write_wakeup(sk) <= 0) {
|
| 496 |
|
|
icsk->icsk_probes_out++;
|
| 497 |
|
|
elapsed = keepalive_intvl_when(tp);
|
| 498 |
|
|
} else {
|
| 499 |
|
|
/* If keepalive was lost due to local congestion,
|
| 500 |
|
|
* try harder.
|
| 501 |
|
|
*/
|
| 502 |
|
|
elapsed = TCP_RESOURCE_PROBE_INTERVAL;
|
| 503 |
|
|
}
|
| 504 |
|
|
} else {
|
| 505 |
|
|
/* It is tp->rcv_tstamp + keepalive_time_when(tp) */
|
| 506 |
|
|
elapsed = keepalive_time_when(tp) - elapsed;
|
| 507 |
|
|
}
|
| 508 |
|
|
|
| 509 |
|
|
TCP_CHECK_TIMER(sk);
|
| 510 |
|
|
sk_stream_mem_reclaim(sk);
|
| 511 |
|
|
|
| 512 |
|
|
resched:
|
| 513 |
|
|
inet_csk_reset_keepalive_timer (sk, elapsed);
|
| 514 |
|
|
goto out;
|
| 515 |
|
|
|
| 516 |
|
|
death:
|
| 517 |
|
|
tcp_done(sk);
|
| 518 |
|
|
|
| 519 |
|
|
out:
|
| 520 |
|
|
bh_unlock_sock(sk);
|
| 521 |
|
|
sock_put(sk);
|
| 522 |
|
|
}
|
