Commit | Line | Data |
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7c657876 ACM |
1 | /* |
2 | * net/dccp/timer.c | |
3 | * | |
4 | * An implementation of the DCCP protocol | |
5 | * Arnaldo Carvalho de Melo <acme@conectiva.com.br> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License | |
9 | * as published by the Free Software Foundation; either version | |
10 | * 2 of the License, or (at your option) any later version. | |
11 | */ | |
12 | ||
13 | #include <linux/config.h> | |
14 | #include <linux/dccp.h> | |
15 | #include <linux/skbuff.h> | |
16 | ||
17 | #include "dccp.h" | |
18 | ||
19 | static void dccp_write_timer(unsigned long data); | |
20 | static void dccp_keepalive_timer(unsigned long data); | |
21 | static void dccp_delack_timer(unsigned long data); | |
22 | ||
23 | void dccp_init_xmit_timers(struct sock *sk) | |
24 | { | |
25 | inet_csk_init_xmit_timers(sk, &dccp_write_timer, &dccp_delack_timer, | |
26 | &dccp_keepalive_timer); | |
27 | } | |
28 | ||
29 | static void dccp_write_err(struct sock *sk) | |
30 | { | |
31 | sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT; | |
32 | sk->sk_error_report(sk); | |
33 | ||
34 | dccp_v4_send_reset(sk, DCCP_RESET_CODE_ABORTED); | |
35 | dccp_done(sk); | |
36 | DCCP_INC_STATS_BH(DCCP_MIB_ABORTONTIMEOUT); | |
37 | } | |
38 | ||
39 | /* A write timeout has occurred. Process the after effects. */ | |
40 | static int dccp_write_timeout(struct sock *sk) | |
41 | { | |
42 | const struct inet_connection_sock *icsk = inet_csk(sk); | |
43 | int retry_until; | |
44 | ||
45 | if (sk->sk_state == DCCP_REQUESTING || sk->sk_state == DCCP_PARTOPEN) { | |
46 | if (icsk->icsk_retransmits != 0) | |
47 | dst_negative_advice(&sk->sk_dst_cache); | |
48 | retry_until = icsk->icsk_syn_retries ? : /* FIXME! */ 3 /* FIXME! sysctl_tcp_syn_retries */; | |
49 | } else { | |
50 | if (icsk->icsk_retransmits >= /* FIXME! sysctl_tcp_retries1 */ 5 /* FIXME! */) { | |
51 | /* NOTE. draft-ietf-tcpimpl-pmtud-01.txt requires pmtu black | |
52 | hole detection. :-( | |
53 | ||
54 | It is place to make it. It is not made. I do not want | |
55 | to make it. It is disguisting. It does not work in any | |
56 | case. Let me to cite the same draft, which requires for | |
57 | us to implement this: | |
58 | ||
59 | "The one security concern raised by this memo is that ICMP black holes | |
60 | are often caused by over-zealous security administrators who block | |
61 | all ICMP messages. It is vitally important that those who design and | |
62 | deploy security systems understand the impact of strict filtering on | |
63 | upper-layer protocols. The safest web site in the world is worthless | |
64 | if most TCP implementations cannot transfer data from it. It would | |
65 | be far nicer to have all of the black holes fixed rather than fixing | |
66 | all of the TCP implementations." | |
67 | ||
68 | Golden words :-). | |
69 | */ | |
70 | ||
71 | dst_negative_advice(&sk->sk_dst_cache); | |
72 | } | |
73 | ||
74 | retry_until = /* FIXME! */ 15 /* FIXME! sysctl_tcp_retries2 */; | |
75 | /* | |
76 | * FIXME: see tcp_write_timout and tcp_out_of_resources | |
77 | */ | |
78 | } | |
79 | ||
80 | if (icsk->icsk_retransmits >= retry_until) { | |
81 | /* Has it gone just too far? */ | |
82 | dccp_write_err(sk); | |
83 | return 1; | |
84 | } | |
85 | return 0; | |
86 | } | |
87 | ||
88 | /* This is the same as tcp_delack_timer, sans prequeue & mem_reclaim stuff */ | |
89 | static void dccp_delack_timer(unsigned long data) | |
90 | { | |
91 | struct sock *sk = (struct sock *)data; | |
92 | struct inet_connection_sock *icsk = inet_csk(sk); | |
93 | ||
94 | bh_lock_sock(sk); | |
95 | if (sock_owned_by_user(sk)) { | |
96 | /* Try again later. */ | |
97 | icsk->icsk_ack.blocked = 1; | |
98 | NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKLOCKED); | |
99 | sk_reset_timer(sk, &icsk->icsk_delack_timer, jiffies + TCP_DELACK_MIN); | |
100 | goto out; | |
101 | } | |
102 | ||
103 | if (sk->sk_state == DCCP_CLOSED || !(icsk->icsk_ack.pending & ICSK_ACK_TIMER)) | |
104 | goto out; | |
105 | if (time_after(icsk->icsk_ack.timeout, jiffies)) { | |
106 | sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout); | |
107 | goto out; | |
108 | } | |
109 | ||
110 | icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER; | |
111 | ||
112 | if (inet_csk_ack_scheduled(sk)) { | |
113 | if (!icsk->icsk_ack.pingpong) { | |
114 | /* Delayed ACK missed: inflate ATO. */ | |
115 | icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1, icsk->icsk_rto); | |
116 | } else { | |
117 | /* Delayed ACK missed: leave pingpong mode and | |
118 | * deflate ATO. | |
119 | */ | |
120 | icsk->icsk_ack.pingpong = 0; | |
121 | icsk->icsk_ack.ato = TCP_ATO_MIN; | |
122 | } | |
123 | dccp_send_ack(sk); | |
124 | NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKS); | |
125 | } | |
126 | out: | |
127 | bh_unlock_sock(sk); | |
128 | sock_put(sk); | |
129 | } | |
130 | ||
131 | /* | |
132 | * The DCCP retransmit timer. | |
133 | */ | |
134 | static void dccp_retransmit_timer(struct sock *sk) | |
135 | { | |
136 | struct inet_connection_sock *icsk = inet_csk(sk); | |
137 | ||
138 | /* | |
139 | * sk->sk_send_head has to have one skb with | |
140 | * DCCP_SKB_CB(skb)->dccpd_type set to one of the retransmittable DCCP | |
141 | * packet types (REQUEST, RESPONSE, the ACK in the 3way hanshake | |
142 | * (PARTOPEN timer), etc). | |
143 | */ | |
144 | BUG_TRAP(sk->sk_send_head != NULL); | |
145 | ||
146 | /* | |
147 | * More than than 4MSL (8 minutes) has passed, a RESET(aborted) was | |
148 | * sent, no need to retransmit, this sock is dead. | |
149 | */ | |
150 | if (dccp_write_timeout(sk)) | |
151 | goto out; | |
152 | ||
153 | /* | |
154 | * We want to know the number of packets retransmitted, not the | |
155 | * total number of retransmissions of clones of original packets. | |
156 | */ | |
157 | if (icsk->icsk_retransmits == 0) | |
158 | DCCP_INC_STATS_BH(DCCP_MIB_TIMEOUTS); | |
159 | ||
160 | if (dccp_retransmit_skb(sk, sk->sk_send_head) < 0) { | |
161 | /* | |
162 | * Retransmission failed because of local congestion, | |
163 | * do not backoff. | |
164 | */ | |
165 | if (icsk->icsk_retransmits == 0) | |
166 | icsk->icsk_retransmits = 1; | |
167 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, | |
168 | min(icsk->icsk_rto, | |
169 | TCP_RESOURCE_PROBE_INTERVAL), | |
170 | TCP_RTO_MAX); | |
171 | goto out; | |
172 | } | |
173 | ||
174 | icsk->icsk_backoff++; | |
175 | icsk->icsk_retransmits++; | |
176 | ||
177 | icsk->icsk_rto = min(icsk->icsk_rto << 1, DCCP_RTO_MAX); | |
178 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto, TCP_RTO_MAX); | |
179 | if (icsk->icsk_retransmits > 3 /* FIXME: sysctl_dccp_retries1 */) | |
180 | __sk_dst_reset(sk); | |
181 | out:; | |
182 | } | |
183 | ||
184 | static void dccp_write_timer(unsigned long data) | |
185 | { | |
186 | struct sock *sk = (struct sock *)data; | |
187 | struct inet_connection_sock *icsk = inet_csk(sk); | |
188 | int event = 0; | |
189 | ||
190 | bh_lock_sock(sk); | |
191 | if (sock_owned_by_user(sk)) { | |
192 | /* Try again later */ | |
193 | sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + (HZ / 20)); | |
194 | goto out; | |
195 | } | |
196 | ||
197 | if (sk->sk_state == DCCP_CLOSED || !icsk->icsk_pending) | |
198 | goto out; | |
199 | ||
200 | if (time_after(icsk->icsk_timeout, jiffies)) { | |
201 | sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout); | |
202 | goto out; | |
203 | } | |
204 | ||
205 | event = icsk->icsk_pending; | |
206 | icsk->icsk_pending = 0; | |
207 | ||
208 | switch (event) { | |
209 | case ICSK_TIME_RETRANS: | |
210 | dccp_retransmit_timer(sk); | |
211 | break; | |
212 | } | |
213 | out: | |
214 | bh_unlock_sock(sk); | |
215 | sock_put(sk); | |
216 | } | |
217 | ||
218 | /* | |
219 | * Timer for listening sockets | |
220 | */ | |
221 | static void dccp_response_timer(struct sock *sk) | |
222 | { | |
a019d6fe | 223 | inet_csk_reqsk_queue_prune(sk, TCP_SYNQ_INTERVAL, DCCP_TIMEOUT_INIT, DCCP_RTO_MAX); |
7c657876 ACM |
224 | } |
225 | ||
226 | static void dccp_keepalive_timer(unsigned long data) | |
227 | { | |
228 | struct sock *sk = (struct sock *)data; | |
229 | ||
230 | /* Only process if socket is not in use. */ | |
231 | bh_lock_sock(sk); | |
232 | if (sock_owned_by_user(sk)) { | |
233 | /* Try again later. */ | |
234 | inet_csk_reset_keepalive_timer(sk, HZ / 20); | |
235 | goto out; | |
236 | } | |
237 | ||
238 | if (sk->sk_state == DCCP_LISTEN) { | |
239 | dccp_response_timer(sk); | |
240 | goto out; | |
241 | } | |
242 | out: | |
243 | bh_unlock_sock(sk); | |
244 | sock_put(sk); | |
245 | } |