Commit | Line | Data |
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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
7c657876 ACM |
2 | /* |
3 | * net/dccp/timer.c | |
8109b02b | 4 | * |
7c657876 ACM |
5 | * An implementation of the DCCP protocol |
6 | * Arnaldo Carvalho de Melo <acme@conectiva.com.br> | |
7c657876 ACM |
7 | */ |
8 | ||
7c657876 ACM |
9 | #include <linux/dccp.h> |
10 | #include <linux/skbuff.h> | |
bc3b2d7f | 11 | #include <linux/export.h> |
7c657876 ACM |
12 | |
13 | #include "dccp.h" | |
14 | ||
2e2e9e92 GR |
15 | /* sysctl variables governing numbers of retransmission attempts */ |
16 | int sysctl_dccp_request_retries __read_mostly = TCP_SYN_RETRIES; | |
17 | int sysctl_dccp_retries1 __read_mostly = TCP_RETR1; | |
18 | int sysctl_dccp_retries2 __read_mostly = TCP_RETR2; | |
19 | ||
7c657876 ACM |
20 | static void dccp_write_err(struct sock *sk) |
21 | { | |
22 | sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT; | |
23 | sk->sk_error_report(sk); | |
24 | ||
017487d7 | 25 | dccp_send_reset(sk, DCCP_RESET_CODE_ABORTED); |
7c657876 | 26 | dccp_done(sk); |
aa62d76b | 27 | __DCCP_INC_STATS(DCCP_MIB_ABORTONTIMEOUT); |
7c657876 ACM |
28 | } |
29 | ||
30 | /* A write timeout has occurred. Process the after effects. */ | |
31 | static int dccp_write_timeout(struct sock *sk) | |
32 | { | |
33 | const struct inet_connection_sock *icsk = inet_csk(sk); | |
34 | int retry_until; | |
35 | ||
36 | if (sk->sk_state == DCCP_REQUESTING || sk->sk_state == DCCP_PARTOPEN) { | |
37 | if (icsk->icsk_retransmits != 0) | |
b6c6712a | 38 | dst_negative_advice(sk); |
2e2e9e92 GR |
39 | retry_until = icsk->icsk_syn_retries ? |
40 | : sysctl_dccp_request_retries; | |
7c657876 | 41 | } else { |
2e2e9e92 | 42 | if (icsk->icsk_retransmits >= sysctl_dccp_retries1) { |
7690af3f ACM |
43 | /* NOTE. draft-ietf-tcpimpl-pmtud-01.txt requires pmtu |
44 | black hole detection. :-( | |
7c657876 ACM |
45 | |
46 | It is place to make it. It is not made. I do not want | |
47 | to make it. It is disguisting. It does not work in any | |
48 | case. Let me to cite the same draft, which requires for | |
49 | us to implement this: | |
50 | ||
51 | "The one security concern raised by this memo is that ICMP black holes | |
52 | are often caused by over-zealous security administrators who block | |
53 | all ICMP messages. It is vitally important that those who design and | |
54 | deploy security systems understand the impact of strict filtering on | |
55 | upper-layer protocols. The safest web site in the world is worthless | |
56 | if most TCP implementations cannot transfer data from it. It would | |
57 | be far nicer to have all of the black holes fixed rather than fixing | |
58 | all of the TCP implementations." | |
59 | ||
c9eaf173 | 60 | Golden words :-). |
7c657876 ACM |
61 | */ |
62 | ||
b6c6712a | 63 | dst_negative_advice(sk); |
7c657876 ACM |
64 | } |
65 | ||
2e2e9e92 | 66 | retry_until = sysctl_dccp_retries2; |
7c657876 ACM |
67 | /* |
68 | * FIXME: see tcp_write_timout and tcp_out_of_resources | |
69 | */ | |
70 | } | |
71 | ||
72 | if (icsk->icsk_retransmits >= retry_until) { | |
73 | /* Has it gone just too far? */ | |
74 | dccp_write_err(sk); | |
75 | return 1; | |
76 | } | |
77 | return 0; | |
78 | } | |
79 | ||
7c657876 ACM |
80 | /* |
81 | * The DCCP retransmit timer. | |
82 | */ | |
83 | static void dccp_retransmit_timer(struct sock *sk) | |
84 | { | |
85 | struct inet_connection_sock *icsk = inet_csk(sk); | |
86 | ||
8109b02b | 87 | /* |
7c657876 ACM |
88 | * More than than 4MSL (8 minutes) has passed, a RESET(aborted) was |
89 | * sent, no need to retransmit, this sock is dead. | |
90 | */ | |
91 | if (dccp_write_timeout(sk)) | |
59435444 | 92 | return; |
7c657876 ACM |
93 | |
94 | /* | |
95 | * We want to know the number of packets retransmitted, not the | |
96 | * total number of retransmissions of clones of original packets. | |
97 | */ | |
98 | if (icsk->icsk_retransmits == 0) | |
aa62d76b | 99 | __DCCP_INC_STATS(DCCP_MIB_TIMEOUTS); |
7c657876 | 100 | |
59435444 | 101 | if (dccp_retransmit_skb(sk) != 0) { |
7c657876 ACM |
102 | /* |
103 | * Retransmission failed because of local congestion, | |
104 | * do not backoff. | |
105 | */ | |
59435444 | 106 | if (--icsk->icsk_retransmits == 0) |
7c657876 ACM |
107 | icsk->icsk_retransmits = 1; |
108 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, | |
109 | min(icsk->icsk_rto, | |
110 | TCP_RESOURCE_PROBE_INTERVAL), | |
7690af3f | 111 | DCCP_RTO_MAX); |
59435444 | 112 | return; |
7c657876 ACM |
113 | } |
114 | ||
115 | icsk->icsk_backoff++; | |
7c657876 ACM |
116 | |
117 | icsk->icsk_rto = min(icsk->icsk_rto << 1, DCCP_RTO_MAX); | |
7690af3f ACM |
118 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto, |
119 | DCCP_RTO_MAX); | |
2e2e9e92 | 120 | if (icsk->icsk_retransmits > sysctl_dccp_retries1) |
7c657876 | 121 | __sk_dst_reset(sk); |
7c657876 ACM |
122 | } |
123 | ||
59f379f9 | 124 | static void dccp_write_timer(struct timer_list *t) |
7c657876 | 125 | { |
59f379f9 KC |
126 | struct inet_connection_sock *icsk = |
127 | from_timer(icsk, t, icsk_retransmit_timer); | |
128 | struct sock *sk = &icsk->icsk_inet.sk; | |
7c657876 ACM |
129 | int event = 0; |
130 | ||
131 | bh_lock_sock(sk); | |
132 | if (sock_owned_by_user(sk)) { | |
133 | /* Try again later */ | |
7690af3f ACM |
134 | sk_reset_timer(sk, &icsk->icsk_retransmit_timer, |
135 | jiffies + (HZ / 20)); | |
7c657876 ACM |
136 | goto out; |
137 | } | |
138 | ||
139 | if (sk->sk_state == DCCP_CLOSED || !icsk->icsk_pending) | |
140 | goto out; | |
141 | ||
142 | if (time_after(icsk->icsk_timeout, jiffies)) { | |
7690af3f ACM |
143 | sk_reset_timer(sk, &icsk->icsk_retransmit_timer, |
144 | icsk->icsk_timeout); | |
7c657876 ACM |
145 | goto out; |
146 | } | |
147 | ||
148 | event = icsk->icsk_pending; | |
149 | icsk->icsk_pending = 0; | |
150 | ||
151 | switch (event) { | |
152 | case ICSK_TIME_RETRANS: | |
153 | dccp_retransmit_timer(sk); | |
154 | break; | |
155 | } | |
156 | out: | |
157 | bh_unlock_sock(sk); | |
158 | sock_put(sk); | |
159 | } | |
160 | ||
59f379f9 | 161 | static void dccp_keepalive_timer(struct timer_list *t) |
7c657876 | 162 | { |
59f379f9 | 163 | struct sock *sk = from_timer(sk, t, sk_timer); |
7c657876 | 164 | |
fa76ce73 | 165 | pr_err("dccp should not use a keepalive timer !\n"); |
7c657876 ACM |
166 | sock_put(sk); |
167 | } | |
4ed800d0 GR |
168 | |
169 | /* This is the same as tcp_delack_timer, sans prequeue & mem_reclaim stuff */ | |
59f379f9 | 170 | static void dccp_delack_timer(struct timer_list *t) |
4ed800d0 | 171 | { |
59f379f9 KC |
172 | struct inet_connection_sock *icsk = |
173 | from_timer(icsk, t, icsk_delack_timer); | |
174 | struct sock *sk = &icsk->icsk_inet.sk; | |
4ed800d0 GR |
175 | |
176 | bh_lock_sock(sk); | |
177 | if (sock_owned_by_user(sk)) { | |
178 | /* Try again later. */ | |
179 | icsk->icsk_ack.blocked = 1; | |
02a1d6e7 | 180 | __NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKLOCKED); |
4ed800d0 GR |
181 | sk_reset_timer(sk, &icsk->icsk_delack_timer, |
182 | jiffies + TCP_DELACK_MIN); | |
183 | goto out; | |
184 | } | |
185 | ||
186 | if (sk->sk_state == DCCP_CLOSED || | |
187 | !(icsk->icsk_ack.pending & ICSK_ACK_TIMER)) | |
188 | goto out; | |
189 | if (time_after(icsk->icsk_ack.timeout, jiffies)) { | |
190 | sk_reset_timer(sk, &icsk->icsk_delack_timer, | |
191 | icsk->icsk_ack.timeout); | |
192 | goto out; | |
193 | } | |
194 | ||
195 | icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER; | |
196 | ||
197 | if (inet_csk_ack_scheduled(sk)) { | |
31954cd8 | 198 | if (!inet_csk_in_pingpong_mode(sk)) { |
4ed800d0 GR |
199 | /* Delayed ACK missed: inflate ATO. */ |
200 | icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1, | |
201 | icsk->icsk_rto); | |
202 | } else { | |
203 | /* Delayed ACK missed: leave pingpong mode and | |
204 | * deflate ATO. | |
205 | */ | |
31954cd8 | 206 | inet_csk_exit_pingpong_mode(sk); |
4ed800d0 GR |
207 | icsk->icsk_ack.ato = TCP_ATO_MIN; |
208 | } | |
209 | dccp_send_ack(sk); | |
02a1d6e7 | 210 | __NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKS); |
4ed800d0 GR |
211 | } |
212 | out: | |
213 | bh_unlock_sock(sk); | |
214 | sock_put(sk); | |
215 | } | |
216 | ||
dc841e30 GR |
217 | /** |
218 | * dccp_write_xmitlet - Workhorse for CCID packet dequeueing interface | |
219 | * See the comments above %ccid_dequeueing_decision for supported modes. | |
220 | */ | |
221 | static void dccp_write_xmitlet(unsigned long data) | |
aabb601b GR |
222 | { |
223 | struct sock *sk = (struct sock *)data; | |
aabb601b GR |
224 | |
225 | bh_lock_sock(sk); | |
226 | if (sock_owned_by_user(sk)) | |
dc841e30 | 227 | sk_reset_timer(sk, &dccp_sk(sk)->dccps_xmit_timer, jiffies + 1); |
aabb601b | 228 | else |
b1fcf55e | 229 | dccp_write_xmit(sk); |
aabb601b | 230 | bh_unlock_sock(sk); |
a8d7aa17 | 231 | sock_put(sk); |
aabb601b GR |
232 | } |
233 | ||
839a6094 | 234 | static void dccp_write_xmit_timer(struct timer_list *t) |
aabb601b | 235 | { |
839a6094 KC |
236 | struct dccp_sock *dp = from_timer(dp, t, dccps_xmit_timer); |
237 | struct sock *sk = &dp->dccps_inet_connection.icsk_inet.sk; | |
238 | ||
239 | dccp_write_xmitlet((unsigned long)sk); | |
aabb601b GR |
240 | } |
241 | ||
4ed800d0 GR |
242 | void dccp_init_xmit_timers(struct sock *sk) |
243 | { | |
dc841e30 GR |
244 | struct dccp_sock *dp = dccp_sk(sk); |
245 | ||
246 | tasklet_init(&dp->dccps_xmitlet, dccp_write_xmitlet, (unsigned long)sk); | |
839a6094 | 247 | timer_setup(&dp->dccps_xmit_timer, dccp_write_xmit_timer, 0); |
4ed800d0 GR |
248 | inet_csk_init_xmit_timers(sk, &dccp_write_timer, &dccp_delack_timer, |
249 | &dccp_keepalive_timer); | |
250 | } | |
4c70f383 GR |
251 | |
252 | static ktime_t dccp_timestamp_seed; | |
253 | /** | |
254 | * dccp_timestamp - 10s of microseconds time source | |
255 | * Returns the number of 10s of microseconds since loading DCCP. This is native | |
256 | * DCCP time difference format (RFC 4340, sec. 13). | |
257 | * Please note: This will wrap around about circa every 11.9 hours. | |
258 | */ | |
259 | u32 dccp_timestamp(void) | |
260 | { | |
5c4a43b0 | 261 | u64 delta = (u64)ktime_us_delta(ktime_get_real(), dccp_timestamp_seed); |
4c70f383 GR |
262 | |
263 | do_div(delta, 10); | |
264 | return delta; | |
265 | } | |
266 | EXPORT_SYMBOL_GPL(dccp_timestamp); | |
267 | ||
268 | void __init dccp_timestamping_init(void) | |
269 | { | |
270 | dccp_timestamp_seed = ktime_get_real(); | |
271 | } |