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 | { | |
9a25f0cb | 22 | sk->sk_err = READ_ONCE(sk->sk_err_soft) ? : ETIMEDOUT; |
e3ae2365 | 23 | sk_error_report(sk); |
7c657876 | 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 | /* |
54633527 | 88 | * More than 4MSL (8 minutes) has passed, a RESET(aborted) was |
7c657876 ACM |
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. */ | |
02a1d6e7 | 179 | __NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKLOCKED); |
4ed800d0 GR |
180 | sk_reset_timer(sk, &icsk->icsk_delack_timer, |
181 | jiffies + TCP_DELACK_MIN); | |
182 | goto out; | |
183 | } | |
184 | ||
185 | if (sk->sk_state == DCCP_CLOSED || | |
186 | !(icsk->icsk_ack.pending & ICSK_ACK_TIMER)) | |
187 | goto out; | |
188 | if (time_after(icsk->icsk_ack.timeout, jiffies)) { | |
189 | sk_reset_timer(sk, &icsk->icsk_delack_timer, | |
190 | icsk->icsk_ack.timeout); | |
191 | goto out; | |
192 | } | |
193 | ||
194 | icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER; | |
195 | ||
196 | if (inet_csk_ack_scheduled(sk)) { | |
31954cd8 | 197 | if (!inet_csk_in_pingpong_mode(sk)) { |
4ed800d0 | 198 | /* Delayed ACK missed: inflate ATO. */ |
95b9a87c DM |
199 | icsk->icsk_ack.ato = min_t(u32, icsk->icsk_ack.ato << 1, |
200 | icsk->icsk_rto); | |
4ed800d0 GR |
201 | } else { |
202 | /* Delayed ACK missed: leave pingpong mode and | |
203 | * deflate ATO. | |
204 | */ | |
31954cd8 | 205 | inet_csk_exit_pingpong_mode(sk); |
4ed800d0 GR |
206 | icsk->icsk_ack.ato = TCP_ATO_MIN; |
207 | } | |
208 | dccp_send_ack(sk); | |
02a1d6e7 | 209 | __NET_INC_STATS(sock_net(sk), LINUX_MIB_DELAYEDACKS); |
4ed800d0 GR |
210 | } |
211 | out: | |
212 | bh_unlock_sock(sk); | |
213 | sock_put(sk); | |
214 | } | |
215 | ||
dc841e30 GR |
216 | /** |
217 | * dccp_write_xmitlet - Workhorse for CCID packet dequeueing interface | |
fccf290f | 218 | * @t: pointer to the tasklet associated with this handler |
d0b1101b | 219 | * |
dc841e30 GR |
220 | * See the comments above %ccid_dequeueing_decision for supported modes. |
221 | */ | |
fccf290f | 222 | static void dccp_write_xmitlet(struct tasklet_struct *t) |
aabb601b | 223 | { |
fccf290f AP |
224 | struct dccp_sock *dp = from_tasklet(dp, t, dccps_xmitlet); |
225 | struct sock *sk = &dp->dccps_inet_connection.icsk_inet.sk; | |
aabb601b GR |
226 | |
227 | bh_lock_sock(sk); | |
228 | if (sock_owned_by_user(sk)) | |
dc841e30 | 229 | sk_reset_timer(sk, &dccp_sk(sk)->dccps_xmit_timer, jiffies + 1); |
aabb601b | 230 | else |
b1fcf55e | 231 | dccp_write_xmit(sk); |
aabb601b | 232 | bh_unlock_sock(sk); |
a8d7aa17 | 233 | sock_put(sk); |
aabb601b GR |
234 | } |
235 | ||
839a6094 | 236 | static void dccp_write_xmit_timer(struct timer_list *t) |
aabb601b | 237 | { |
839a6094 | 238 | struct dccp_sock *dp = from_timer(dp, t, dccps_xmit_timer); |
839a6094 | 239 | |
fccf290f | 240 | dccp_write_xmitlet(&dp->dccps_xmitlet); |
aabb601b GR |
241 | } |
242 | ||
4ed800d0 GR |
243 | void dccp_init_xmit_timers(struct sock *sk) |
244 | { | |
dc841e30 GR |
245 | struct dccp_sock *dp = dccp_sk(sk); |
246 | ||
fccf290f | 247 | tasklet_setup(&dp->dccps_xmitlet, dccp_write_xmitlet); |
839a6094 | 248 | timer_setup(&dp->dccps_xmit_timer, dccp_write_xmit_timer, 0); |
4ed800d0 GR |
249 | inet_csk_init_xmit_timers(sk, &dccp_write_timer, &dccp_delack_timer, |
250 | &dccp_keepalive_timer); | |
251 | } | |
4c70f383 GR |
252 | |
253 | static ktime_t dccp_timestamp_seed; | |
254 | /** | |
255 | * dccp_timestamp - 10s of microseconds time source | |
256 | * Returns the number of 10s of microseconds since loading DCCP. This is native | |
257 | * DCCP time difference format (RFC 4340, sec. 13). | |
258 | * Please note: This will wrap around about circa every 11.9 hours. | |
259 | */ | |
260 | u32 dccp_timestamp(void) | |
261 | { | |
5c4a43b0 | 262 | u64 delta = (u64)ktime_us_delta(ktime_get_real(), dccp_timestamp_seed); |
4c70f383 GR |
263 | |
264 | do_div(delta, 10); | |
265 | return delta; | |
266 | } | |
267 | EXPORT_SYMBOL_GPL(dccp_timestamp); | |
268 | ||
269 | void __init dccp_timestamping_init(void) | |
270 | { | |
271 | dccp_timestamp_seed = ktime_get_real(); | |
272 | } |