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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
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 | * Definitions for the TCP module. | |
7 | * | |
8 | * Version: @(#)tcp.h 1.0.5 05/23/93 | |
9 | * | |
02c30a84 | 10 | * Authors: Ross Biro |
1da177e4 LT |
11 | * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> |
12 | * | |
13 | * This program is free software; you can redistribute it and/or | |
14 | * modify it under the terms of the GNU General Public License | |
15 | * as published by the Free Software Foundation; either version | |
16 | * 2 of the License, or (at your option) any later version. | |
17 | */ | |
18 | #ifndef _TCP_H | |
19 | #define _TCP_H | |
20 | ||
21 | #define TCP_DEBUG 1 | |
22 | #define FASTRETRANS_DEBUG 1 | |
23 | ||
1da177e4 LT |
24 | #include <linux/list.h> |
25 | #include <linux/tcp.h> | |
26 | #include <linux/slab.h> | |
27 | #include <linux/cache.h> | |
28 | #include <linux/percpu.h> | |
fb286bb2 | 29 | #include <linux/skbuff.h> |
97fc2f08 | 30 | #include <linux/dmaengine.h> |
cfb6eeb4 | 31 | #include <linux/crypto.h> |
c6aefafb | 32 | #include <linux/cryptohash.h> |
435cf559 | 33 | #include <linux/kref.h> |
3f421baa ACM |
34 | |
35 | #include <net/inet_connection_sock.h> | |
295ff7ed | 36 | #include <net/inet_timewait_sock.h> |
77d8bf9c | 37 | #include <net/inet_hashtables.h> |
1da177e4 | 38 | #include <net/checksum.h> |
2e6599cb | 39 | #include <net/request_sock.h> |
1da177e4 LT |
40 | #include <net/sock.h> |
41 | #include <net/snmp.h> | |
42 | #include <net/ip.h> | |
c752f073 | 43 | #include <net/tcp_states.h> |
bdf1ee5d | 44 | #include <net/inet_ecn.h> |
0c266898 | 45 | #include <net/dst.h> |
c752f073 | 46 | |
1da177e4 LT |
47 | #include <linux/seq_file.h> |
48 | ||
6e04e021 | 49 | extern struct inet_hashinfo tcp_hashinfo; |
1da177e4 | 50 | |
dd24c001 | 51 | extern struct percpu_counter tcp_orphan_count; |
1da177e4 | 52 | extern void tcp_time_wait(struct sock *sk, int state, int timeo); |
1da177e4 | 53 | |
1da177e4 | 54 | #define MAX_TCP_HEADER (128 + MAX_HEADER) |
33ad798c | 55 | #define MAX_TCP_OPTION_SPACE 40 |
1da177e4 LT |
56 | |
57 | /* | |
58 | * Never offer a window over 32767 without using window scaling. Some | |
59 | * poor stacks do signed 16bit maths! | |
60 | */ | |
61 | #define MAX_TCP_WINDOW 32767U | |
62 | ||
63 | /* Minimal accepted MSS. It is (60+60+8) - (20+20). */ | |
64 | #define TCP_MIN_MSS 88U | |
65 | ||
5d424d5a JH |
66 | /* The least MTU to use for probing */ |
67 | #define TCP_BASE_MSS 512 | |
68 | ||
1da177e4 LT |
69 | /* After receiving this amount of duplicate ACKs fast retransmit starts. */ |
70 | #define TCP_FASTRETRANS_THRESH 3 | |
71 | ||
72 | /* Maximal reordering. */ | |
73 | #define TCP_MAX_REORDERING 127 | |
74 | ||
75 | /* Maximal number of ACKs sent quickly to accelerate slow-start. */ | |
76 | #define TCP_MAX_QUICKACKS 16U | |
77 | ||
78 | /* urg_data states */ | |
79 | #define TCP_URG_VALID 0x0100 | |
80 | #define TCP_URG_NOTYET 0x0200 | |
81 | #define TCP_URG_READ 0x0400 | |
82 | ||
83 | #define TCP_RETR1 3 /* | |
84 | * This is how many retries it does before it | |
85 | * tries to figure out if the gateway is | |
86 | * down. Minimal RFC value is 3; it corresponds | |
87 | * to ~3sec-8min depending on RTO. | |
88 | */ | |
89 | ||
90 | #define TCP_RETR2 15 /* | |
91 | * This should take at least | |
92 | * 90 minutes to time out. | |
93 | * RFC1122 says that the limit is 100 sec. | |
94 | * 15 is ~13-30min depending on RTO. | |
95 | */ | |
96 | ||
97 | #define TCP_SYN_RETRIES 5 /* number of times to retry active opening a | |
caa20d9a | 98 | * connection: ~180sec is RFC minimum */ |
1da177e4 LT |
99 | |
100 | #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a | |
caa20d9a | 101 | * connection: ~180sec is RFC minimum */ |
1da177e4 | 102 | |
1da177e4 LT |
103 | #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT |
104 | * state, about 60 seconds */ | |
105 | #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN | |
106 | /* BSD style FIN_WAIT2 deadlock breaker. | |
107 | * It used to be 3min, new value is 60sec, | |
108 | * to combine FIN-WAIT-2 timeout with | |
109 | * TIME-WAIT timer. | |
110 | */ | |
111 | ||
112 | #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ | |
113 | #if HZ >= 100 | |
114 | #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ | |
115 | #define TCP_ATO_MIN ((unsigned)(HZ/25)) | |
116 | #else | |
117 | #define TCP_DELACK_MIN 4U | |
118 | #define TCP_ATO_MIN 4U | |
119 | #endif | |
120 | #define TCP_RTO_MAX ((unsigned)(120*HZ)) | |
121 | #define TCP_RTO_MIN ((unsigned)(HZ/5)) | |
122 | #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */ | |
123 | ||
124 | #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes | |
125 | * for local resources. | |
126 | */ | |
127 | ||
128 | #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ | |
129 | #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ | |
130 | #define TCP_KEEPALIVE_INTVL (75*HZ) | |
131 | ||
132 | #define MAX_TCP_KEEPIDLE 32767 | |
133 | #define MAX_TCP_KEEPINTVL 32767 | |
134 | #define MAX_TCP_KEEPCNT 127 | |
135 | #define MAX_TCP_SYNCNT 127 | |
136 | ||
137 | #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ | |
1da177e4 LT |
138 | |
139 | #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) | |
140 | #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated | |
141 | * after this time. It should be equal | |
142 | * (or greater than) TCP_TIMEWAIT_LEN | |
143 | * to provide reliability equal to one | |
144 | * provided by timewait state. | |
145 | */ | |
146 | #define TCP_PAWS_WINDOW 1 /* Replay window for per-host | |
147 | * timestamps. It must be less than | |
148 | * minimal timewait lifetime. | |
149 | */ | |
1da177e4 LT |
150 | /* |
151 | * TCP option | |
152 | */ | |
153 | ||
154 | #define TCPOPT_NOP 1 /* Padding */ | |
155 | #define TCPOPT_EOL 0 /* End of options */ | |
156 | #define TCPOPT_MSS 2 /* Segment size negotiating */ | |
157 | #define TCPOPT_WINDOW 3 /* Window scaling */ | |
158 | #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ | |
159 | #define TCPOPT_SACK 5 /* SACK Block */ | |
160 | #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ | |
cfb6eeb4 | 161 | #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ |
435cf559 | 162 | #define TCPOPT_COOKIE 253 /* Cookie extension (experimental) */ |
1da177e4 LT |
163 | |
164 | /* | |
165 | * TCP option lengths | |
166 | */ | |
167 | ||
168 | #define TCPOLEN_MSS 4 | |
169 | #define TCPOLEN_WINDOW 3 | |
170 | #define TCPOLEN_SACK_PERM 2 | |
171 | #define TCPOLEN_TIMESTAMP 10 | |
cfb6eeb4 | 172 | #define TCPOLEN_MD5SIG 18 |
435cf559 WAS |
173 | #define TCPOLEN_COOKIE_BASE 2 /* Cookie-less header extension */ |
174 | #define TCPOLEN_COOKIE_PAIR 3 /* Cookie pair header extension */ | |
175 | #define TCPOLEN_COOKIE_MIN (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MIN) | |
176 | #define TCPOLEN_COOKIE_MAX (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MAX) | |
1da177e4 LT |
177 | |
178 | /* But this is what stacks really send out. */ | |
179 | #define TCPOLEN_TSTAMP_ALIGNED 12 | |
180 | #define TCPOLEN_WSCALE_ALIGNED 4 | |
181 | #define TCPOLEN_SACKPERM_ALIGNED 4 | |
182 | #define TCPOLEN_SACK_BASE 2 | |
183 | #define TCPOLEN_SACK_BASE_ALIGNED 4 | |
184 | #define TCPOLEN_SACK_PERBLOCK 8 | |
cfb6eeb4 | 185 | #define TCPOLEN_MD5SIG_ALIGNED 20 |
33ad798c | 186 | #define TCPOLEN_MSS_ALIGNED 4 |
1da177e4 | 187 | |
1da177e4 LT |
188 | /* Flags in tp->nonagle */ |
189 | #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ | |
190 | #define TCP_NAGLE_CORK 2 /* Socket is corked */ | |
caa20d9a | 191 | #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ |
1da177e4 | 192 | |
36e31b0a AP |
193 | /* TCP thin-stream limits */ |
194 | #define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */ | |
195 | ||
295ff7ed ACM |
196 | extern struct inet_timewait_death_row tcp_death_row; |
197 | ||
1da177e4 | 198 | /* sysctl variables for tcp */ |
1da177e4 LT |
199 | extern int sysctl_tcp_timestamps; |
200 | extern int sysctl_tcp_window_scaling; | |
201 | extern int sysctl_tcp_sack; | |
202 | extern int sysctl_tcp_fin_timeout; | |
1da177e4 LT |
203 | extern int sysctl_tcp_keepalive_time; |
204 | extern int sysctl_tcp_keepalive_probes; | |
205 | extern int sysctl_tcp_keepalive_intvl; | |
206 | extern int sysctl_tcp_syn_retries; | |
207 | extern int sysctl_tcp_synack_retries; | |
208 | extern int sysctl_tcp_retries1; | |
209 | extern int sysctl_tcp_retries2; | |
210 | extern int sysctl_tcp_orphan_retries; | |
211 | extern int sysctl_tcp_syncookies; | |
212 | extern int sysctl_tcp_retrans_collapse; | |
213 | extern int sysctl_tcp_stdurg; | |
214 | extern int sysctl_tcp_rfc1337; | |
215 | extern int sysctl_tcp_abort_on_overflow; | |
216 | extern int sysctl_tcp_max_orphans; | |
1da177e4 LT |
217 | extern int sysctl_tcp_fack; |
218 | extern int sysctl_tcp_reordering; | |
219 | extern int sysctl_tcp_ecn; | |
220 | extern int sysctl_tcp_dsack; | |
8d987e5c | 221 | extern long sysctl_tcp_mem[3]; |
1da177e4 LT |
222 | extern int sysctl_tcp_wmem[3]; |
223 | extern int sysctl_tcp_rmem[3]; | |
224 | extern int sysctl_tcp_app_win; | |
225 | extern int sysctl_tcp_adv_win_scale; | |
226 | extern int sysctl_tcp_tw_reuse; | |
227 | extern int sysctl_tcp_frto; | |
3cfe3baa | 228 | extern int sysctl_tcp_frto_response; |
1da177e4 | 229 | extern int sysctl_tcp_low_latency; |
95937825 | 230 | extern int sysctl_tcp_dma_copybreak; |
1da177e4 | 231 | extern int sysctl_tcp_nometrics_save; |
1da177e4 LT |
232 | extern int sysctl_tcp_moderate_rcvbuf; |
233 | extern int sysctl_tcp_tso_win_divisor; | |
9772efb9 | 234 | extern int sysctl_tcp_abc; |
5d424d5a JH |
235 | extern int sysctl_tcp_mtu_probing; |
236 | extern int sysctl_tcp_base_mss; | |
15d99e02 | 237 | extern int sysctl_tcp_workaround_signed_windows; |
35089bb2 | 238 | extern int sysctl_tcp_slow_start_after_idle; |
886236c1 | 239 | extern int sysctl_tcp_max_ssthresh; |
519855c5 | 240 | extern int sysctl_tcp_cookie_size; |
36e31b0a | 241 | extern int sysctl_tcp_thin_linear_timeouts; |
7e380175 | 242 | extern int sysctl_tcp_thin_dupack; |
1da177e4 | 243 | |
8d987e5c | 244 | extern atomic_long_t tcp_memory_allocated; |
1748376b | 245 | extern struct percpu_counter tcp_sockets_allocated; |
1da177e4 LT |
246 | extern int tcp_memory_pressure; |
247 | ||
1da177e4 LT |
248 | /* |
249 | * The next routines deal with comparing 32 bit unsigned ints | |
250 | * and worry about wraparound (automatic with unsigned arithmetic). | |
251 | */ | |
252 | ||
253 | static inline int before(__u32 seq1, __u32 seq2) | |
254 | { | |
0d630cc0 | 255 | return (__s32)(seq1-seq2) < 0; |
1da177e4 | 256 | } |
9a036b9c | 257 | #define after(seq2, seq1) before(seq1, seq2) |
1da177e4 LT |
258 | |
259 | /* is s2<=s1<=s3 ? */ | |
260 | static inline int between(__u32 seq1, __u32 seq2, __u32 seq3) | |
261 | { | |
262 | return seq3 - seq2 >= seq1 - seq2; | |
263 | } | |
264 | ||
ad1af0fe | 265 | static inline bool tcp_too_many_orphans(struct sock *sk, int shift) |
e4fd5da3 | 266 | { |
ad1af0fe DM |
267 | struct percpu_counter *ocp = sk->sk_prot->orphan_count; |
268 | int orphans = percpu_counter_read_positive(ocp); | |
269 | ||
270 | if (orphans << shift > sysctl_tcp_max_orphans) { | |
271 | orphans = percpu_counter_sum_positive(ocp); | |
272 | if (orphans << shift > sysctl_tcp_max_orphans) | |
273 | return true; | |
274 | } | |
275 | ||
276 | if (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && | |
8d987e5c | 277 | atomic_long_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]) |
ad1af0fe DM |
278 | return true; |
279 | return false; | |
e4fd5da3 | 280 | } |
1da177e4 | 281 | |
a0f82f64 FW |
282 | /* syncookies: remember time of last synqueue overflow */ |
283 | static inline void tcp_synq_overflow(struct sock *sk) | |
284 | { | |
285 | tcp_sk(sk)->rx_opt.ts_recent_stamp = jiffies; | |
286 | } | |
287 | ||
288 | /* syncookies: no recent synqueue overflow on this listening socket? */ | |
289 | static inline int tcp_synq_no_recent_overflow(const struct sock *sk) | |
290 | { | |
291 | unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp; | |
292 | return time_after(jiffies, last_overflow + TCP_TIMEOUT_INIT); | |
293 | } | |
294 | ||
1da177e4 LT |
295 | extern struct proto tcp_prot; |
296 | ||
57ef42d5 PE |
297 | #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field) |
298 | #define TCP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.tcp_statistics, field) | |
299 | #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field) | |
300 | #define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val) | |
aa2ea058 | 301 | #define TCP_ADD_STATS(net, field, val) SNMP_ADD_STATS((net)->mib.tcp_statistics, field, val) |
1da177e4 | 302 | |
53d3176b CG |
303 | extern void tcp_v4_err(struct sk_buff *skb, u32); |
304 | ||
305 | extern void tcp_shutdown (struct sock *sk, int how); | |
306 | ||
307 | extern int tcp_v4_rcv(struct sk_buff *skb); | |
308 | ||
3f419d2d | 309 | extern struct inet_peer *tcp_v4_get_peer(struct sock *sk, bool *release_it); |
ccb7c410 | 310 | extern void *tcp_v4_tw_get_peer(struct sock *sk); |
53d3176b | 311 | extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); |
7ba42910 CG |
312 | extern int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, |
313 | size_t size); | |
314 | extern int tcp_sendpage(struct sock *sk, struct page *page, int offset, | |
315 | size_t size, int flags); | |
53d3176b CG |
316 | extern int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg); |
317 | extern int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb, | |
318 | struct tcphdr *th, unsigned len); | |
319 | extern int tcp_rcv_established(struct sock *sk, struct sk_buff *skb, | |
320 | struct tcphdr *th, unsigned len); | |
321 | extern void tcp_rcv_space_adjust(struct sock *sk); | |
322 | extern void tcp_cleanup_rbuf(struct sock *sk, int copied); | |
323 | extern int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp); | |
324 | extern void tcp_twsk_destructor(struct sock *sk); | |
325 | extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos, | |
326 | struct pipe_inode_info *pipe, size_t len, | |
327 | unsigned int flags); | |
9c55e01c | 328 | |
463c84b9 ACM |
329 | static inline void tcp_dec_quickack_mode(struct sock *sk, |
330 | const unsigned int pkts) | |
1da177e4 | 331 | { |
463c84b9 | 332 | struct inet_connection_sock *icsk = inet_csk(sk); |
fc6415bc | 333 | |
463c84b9 ACM |
334 | if (icsk->icsk_ack.quick) { |
335 | if (pkts >= icsk->icsk_ack.quick) { | |
336 | icsk->icsk_ack.quick = 0; | |
fc6415bc | 337 | /* Leaving quickack mode we deflate ATO. */ |
463c84b9 | 338 | icsk->icsk_ack.ato = TCP_ATO_MIN; |
fc6415bc | 339 | } else |
463c84b9 | 340 | icsk->icsk_ack.quick -= pkts; |
1da177e4 LT |
341 | } |
342 | } | |
343 | ||
bdf1ee5d IJ |
344 | #define TCP_ECN_OK 1 |
345 | #define TCP_ECN_QUEUE_CWR 2 | |
346 | #define TCP_ECN_DEMAND_CWR 4 | |
347 | ||
348 | static __inline__ void | |
349 | TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th) | |
350 | { | |
351 | if (sysctl_tcp_ecn && th->ece && th->cwr) | |
352 | inet_rsk(req)->ecn_ok = 1; | |
353 | } | |
354 | ||
fd2c3ef7 | 355 | enum tcp_tw_status { |
1da177e4 LT |
356 | TCP_TW_SUCCESS = 0, |
357 | TCP_TW_RST = 1, | |
358 | TCP_TW_ACK = 2, | |
359 | TCP_TW_SYN = 3 | |
360 | }; | |
361 | ||
362 | ||
53d3176b CG |
363 | extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, |
364 | struct sk_buff *skb, | |
365 | const struct tcphdr *th); | |
366 | extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb, | |
367 | struct request_sock *req, | |
368 | struct request_sock **prev); | |
369 | extern int tcp_child_process(struct sock *parent, struct sock *child, | |
370 | struct sk_buff *skb); | |
371 | extern int tcp_use_frto(struct sock *sk); | |
372 | extern void tcp_enter_frto(struct sock *sk); | |
373 | extern void tcp_enter_loss(struct sock *sk, int how); | |
374 | extern void tcp_clear_retrans(struct tcp_sock *tp); | |
375 | extern void tcp_update_metrics(struct sock *sk); | |
376 | extern void tcp_close(struct sock *sk, long timeout); | |
377 | extern unsigned int tcp_poll(struct file * file, struct socket *sock, | |
378 | struct poll_table_struct *wait); | |
379 | extern int tcp_getsockopt(struct sock *sk, int level, int optname, | |
380 | char __user *optval, int __user *optlen); | |
381 | extern int tcp_setsockopt(struct sock *sk, int level, int optname, | |
382 | char __user *optval, unsigned int optlen); | |
383 | extern int compat_tcp_getsockopt(struct sock *sk, int level, int optname, | |
384 | char __user *optval, int __user *optlen); | |
385 | extern int compat_tcp_setsockopt(struct sock *sk, int level, int optname, | |
386 | char __user *optval, unsigned int optlen); | |
387 | extern void tcp_set_keepalive(struct sock *sk, int val); | |
388 | extern void tcp_syn_ack_timeout(struct sock *sk, struct request_sock *req); | |
389 | extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, | |
390 | size_t len, int nonblock, int flags, int *addr_len); | |
391 | extern void tcp_parse_options(struct sk_buff *skb, | |
392 | struct tcp_options_received *opt_rx, u8 **hvpp, | |
393 | int estab); | |
394 | extern u8 *tcp_parse_md5sig_option(struct tcphdr *th); | |
7d5d5525 | 395 | |
1da177e4 LT |
396 | /* |
397 | * TCP v4 functions exported for the inet6 API | |
398 | */ | |
399 | ||
53d3176b CG |
400 | extern void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb); |
401 | extern int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb); | |
402 | extern struct sock * tcp_create_openreq_child(struct sock *sk, | |
403 | struct request_sock *req, | |
1da177e4 | 404 | struct sk_buff *skb); |
53d3176b CG |
405 | extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb, |
406 | struct request_sock *req, | |
407 | struct dst_entry *dst); | |
408 | extern int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb); | |
409 | extern int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, | |
410 | int addr_len); | |
411 | extern int tcp_connect(struct sock *sk); | |
412 | extern struct sk_buff * tcp_make_synack(struct sock *sk, struct dst_entry *dst, | |
413 | struct request_sock *req, | |
414 | struct request_values *rvp); | |
415 | extern int tcp_disconnect(struct sock *sk, int flags); | |
1da177e4 | 416 | |
1da177e4 | 417 | |
1da177e4 | 418 | /* From syncookies.c */ |
2051f11f | 419 | extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS]; |
1da177e4 LT |
420 | extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, |
421 | struct ip_options *opt); | |
422 | extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, | |
423 | __u16 *mss); | |
424 | ||
4dfc2817 | 425 | extern __u32 cookie_init_timestamp(struct request_sock *req); |
172d69e6 | 426 | extern bool cookie_check_timestamp(struct tcp_options_received *opt, bool *); |
4dfc2817 | 427 | |
c6aefafb GG |
428 | /* From net/ipv6/syncookies.c */ |
429 | extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb); | |
430 | extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb, | |
431 | __u16 *mss); | |
432 | ||
1da177e4 LT |
433 | /* tcp_output.c */ |
434 | ||
9e412ba7 IJ |
435 | extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, |
436 | int nonagle); | |
437 | extern int tcp_may_send_now(struct sock *sk); | |
1da177e4 | 438 | extern int tcp_retransmit_skb(struct sock *, struct sk_buff *); |
f1ecd5d9 | 439 | extern void tcp_retransmit_timer(struct sock *sk); |
1da177e4 LT |
440 | extern void tcp_xmit_retransmit_queue(struct sock *); |
441 | extern void tcp_simple_retransmit(struct sock *); | |
442 | extern int tcp_trim_head(struct sock *, struct sk_buff *, u32); | |
6475be16 | 443 | extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int); |
1da177e4 LT |
444 | |
445 | extern void tcp_send_probe0(struct sock *); | |
446 | extern void tcp_send_partial(struct sock *); | |
53d3176b | 447 | extern int tcp_write_wakeup(struct sock *); |
1da177e4 | 448 | extern void tcp_send_fin(struct sock *sk); |
dd0fc66f | 449 | extern void tcp_send_active_reset(struct sock *sk, gfp_t priority); |
53d3176b | 450 | extern int tcp_send_synack(struct sock *); |
c1b4a7e6 | 451 | extern void tcp_push_one(struct sock *, unsigned int mss_now); |
1da177e4 LT |
452 | extern void tcp_send_ack(struct sock *sk); |
453 | extern void tcp_send_delayed_ack(struct sock *sk); | |
454 | ||
a762a980 DM |
455 | /* tcp_input.c */ |
456 | extern void tcp_cwnd_application_limited(struct sock *sk); | |
457 | ||
1da177e4 LT |
458 | /* tcp_timer.c */ |
459 | extern void tcp_init_xmit_timers(struct sock *); | |
463c84b9 ACM |
460 | static inline void tcp_clear_xmit_timers(struct sock *sk) |
461 | { | |
462 | inet_csk_clear_xmit_timers(sk); | |
463 | } | |
1da177e4 | 464 | |
1da177e4 | 465 | extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); |
0c54b85f IJ |
466 | extern unsigned int tcp_current_mss(struct sock *sk); |
467 | ||
468 | /* Bound MSS / TSO packet size with the half of the window */ | |
469 | static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) | |
470 | { | |
01f83d69 AK |
471 | int cutoff; |
472 | ||
473 | /* When peer uses tiny windows, there is no use in packetizing | |
474 | * to sub-MSS pieces for the sake of SWS or making sure there | |
475 | * are enough packets in the pipe for fast recovery. | |
476 | * | |
477 | * On the other hand, for extremely large MSS devices, handling | |
478 | * smaller than MSS windows in this way does make sense. | |
479 | */ | |
480 | if (tp->max_window >= 512) | |
481 | cutoff = (tp->max_window >> 1); | |
482 | else | |
483 | cutoff = tp->max_window; | |
484 | ||
485 | if (cutoff && pktsize > cutoff) | |
486 | return max_t(int, cutoff, 68U - tp->tcp_header_len); | |
0c54b85f IJ |
487 | else |
488 | return pktsize; | |
489 | } | |
1da177e4 | 490 | |
17b085ea | 491 | /* tcp.c */ |
1da177e4 LT |
492 | extern void tcp_get_info(struct sock *, struct tcp_info *); |
493 | ||
494 | /* Read 'sendfile()'-style from a TCP socket */ | |
495 | typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *, | |
496 | unsigned int, size_t); | |
497 | extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, | |
498 | sk_read_actor_t recv_actor); | |
499 | ||
40efc6fa | 500 | extern void tcp_initialize_rcv_mss(struct sock *sk); |
1da177e4 | 501 | |
5d424d5a JH |
502 | extern int tcp_mtu_to_mss(struct sock *sk, int pmtu); |
503 | extern int tcp_mss_to_mtu(struct sock *sk, int mss); | |
504 | extern void tcp_mtup_init(struct sock *sk); | |
505 | ||
f1ecd5d9 DL |
506 | static inline void tcp_bound_rto(const struct sock *sk) |
507 | { | |
508 | if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX) | |
509 | inet_csk(sk)->icsk_rto = TCP_RTO_MAX; | |
510 | } | |
511 | ||
512 | static inline u32 __tcp_set_rto(const struct tcp_sock *tp) | |
513 | { | |
514 | return (tp->srtt >> 3) + tp->rttvar; | |
515 | } | |
516 | ||
40efc6fa | 517 | static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) |
1da177e4 LT |
518 | { |
519 | tp->pred_flags = htonl((tp->tcp_header_len << 26) | | |
520 | ntohl(TCP_FLAG_ACK) | | |
521 | snd_wnd); | |
522 | } | |
523 | ||
40efc6fa | 524 | static inline void tcp_fast_path_on(struct tcp_sock *tp) |
1da177e4 LT |
525 | { |
526 | __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); | |
527 | } | |
528 | ||
9e412ba7 | 529 | static inline void tcp_fast_path_check(struct sock *sk) |
1da177e4 | 530 | { |
9e412ba7 IJ |
531 | struct tcp_sock *tp = tcp_sk(sk); |
532 | ||
b03efcfb | 533 | if (skb_queue_empty(&tp->out_of_order_queue) && |
1da177e4 LT |
534 | tp->rcv_wnd && |
535 | atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && | |
536 | !tp->urg_data) | |
537 | tcp_fast_path_on(tp); | |
538 | } | |
539 | ||
0c266898 SS |
540 | /* Compute the actual rto_min value */ |
541 | static inline u32 tcp_rto_min(struct sock *sk) | |
542 | { | |
543 | struct dst_entry *dst = __sk_dst_get(sk); | |
544 | u32 rto_min = TCP_RTO_MIN; | |
545 | ||
546 | if (dst && dst_metric_locked(dst, RTAX_RTO_MIN)) | |
547 | rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN); | |
548 | return rto_min; | |
549 | } | |
550 | ||
1da177e4 LT |
551 | /* Compute the actual receive window we are currently advertising. |
552 | * Rcv_nxt can be after the window if our peer push more data | |
553 | * than the offered window. | |
554 | */ | |
40efc6fa | 555 | static inline u32 tcp_receive_window(const struct tcp_sock *tp) |
1da177e4 LT |
556 | { |
557 | s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; | |
558 | ||
559 | if (win < 0) | |
560 | win = 0; | |
561 | return (u32) win; | |
562 | } | |
563 | ||
564 | /* Choose a new window, without checks for shrinking, and without | |
565 | * scaling applied to the result. The caller does these things | |
566 | * if necessary. This is a "raw" window selection. | |
567 | */ | |
53d3176b | 568 | extern u32 __tcp_select_window(struct sock *sk); |
1da177e4 LT |
569 | |
570 | /* TCP timestamps are only 32-bits, this causes a slight | |
571 | * complication on 64-bit systems since we store a snapshot | |
31f34269 SH |
572 | * of jiffies in the buffer control blocks below. We decided |
573 | * to use only the low 32-bits of jiffies and hide the ugly | |
1da177e4 LT |
574 | * casts with the following macro. |
575 | */ | |
576 | #define tcp_time_stamp ((__u32)(jiffies)) | |
577 | ||
a3433f35 CG |
578 | #define tcp_flag_byte(th) (((u_int8_t *)th)[13]) |
579 | ||
580 | #define TCPHDR_FIN 0x01 | |
581 | #define TCPHDR_SYN 0x02 | |
582 | #define TCPHDR_RST 0x04 | |
583 | #define TCPHDR_PSH 0x08 | |
584 | #define TCPHDR_ACK 0x10 | |
585 | #define TCPHDR_URG 0x20 | |
586 | #define TCPHDR_ECE 0x40 | |
587 | #define TCPHDR_CWR 0x80 | |
588 | ||
caa20d9a | 589 | /* This is what the send packet queuing engine uses to pass |
f86586fa ED |
590 | * TCP per-packet control information to the transmission code. |
591 | * We also store the host-order sequence numbers in here too. | |
592 | * This is 44 bytes if IPV6 is enabled. | |
593 | * If this grows please adjust skbuff.h:skbuff->cb[xxx] size appropriately. | |
1da177e4 LT |
594 | */ |
595 | struct tcp_skb_cb { | |
596 | union { | |
597 | struct inet_skb_parm h4; | |
598 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) | |
599 | struct inet6_skb_parm h6; | |
600 | #endif | |
601 | } header; /* For incoming frames */ | |
602 | __u32 seq; /* Starting sequence number */ | |
603 | __u32 end_seq; /* SEQ + FIN + SYN + datalen */ | |
604 | __u32 when; /* used to compute rtt's */ | |
605 | __u8 flags; /* TCP header flags. */ | |
1da177e4 LT |
606 | __u8 sacked; /* State flags for SACK/FACK. */ |
607 | #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ | |
608 | #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ | |
609 | #define TCPCB_LOST 0x04 /* SKB is lost */ | |
610 | #define TCPCB_TAGBITS 0x07 /* All tag bits */ | |
611 | ||
612 | #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ | |
613 | #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS) | |
614 | ||
1da177e4 LT |
615 | __u32 ack_seq; /* Sequence number ACK'd */ |
616 | }; | |
617 | ||
618 | #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) | |
619 | ||
1da177e4 LT |
620 | /* Due to TSO, an SKB can be composed of multiple actual |
621 | * packets. To keep these tracked properly, we use this. | |
622 | */ | |
623 | static inline int tcp_skb_pcount(const struct sk_buff *skb) | |
624 | { | |
7967168c | 625 | return skb_shinfo(skb)->gso_segs; |
1da177e4 LT |
626 | } |
627 | ||
628 | /* This is valid iff tcp_skb_pcount() > 1. */ | |
629 | static inline int tcp_skb_mss(const struct sk_buff *skb) | |
630 | { | |
7967168c | 631 | return skb_shinfo(skb)->gso_size; |
1da177e4 LT |
632 | } |
633 | ||
317a76f9 SH |
634 | /* Events passed to congestion control interface */ |
635 | enum tcp_ca_event { | |
636 | CA_EVENT_TX_START, /* first transmit when no packets in flight */ | |
637 | CA_EVENT_CWND_RESTART, /* congestion window restart */ | |
638 | CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ | |
639 | CA_EVENT_FRTO, /* fast recovery timeout */ | |
640 | CA_EVENT_LOSS, /* loss timeout */ | |
641 | CA_EVENT_FAST_ACK, /* in sequence ack */ | |
642 | CA_EVENT_SLOW_ACK, /* other ack */ | |
643 | }; | |
644 | ||
645 | /* | |
646 | * Interface for adding new TCP congestion control handlers | |
647 | */ | |
648 | #define TCP_CA_NAME_MAX 16 | |
3ff825b2 SH |
649 | #define TCP_CA_MAX 128 |
650 | #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) | |
651 | ||
164891aa SH |
652 | #define TCP_CONG_NON_RESTRICTED 0x1 |
653 | #define TCP_CONG_RTT_STAMP 0x2 | |
654 | ||
317a76f9 SH |
655 | struct tcp_congestion_ops { |
656 | struct list_head list; | |
164891aa | 657 | unsigned long flags; |
317a76f9 SH |
658 | |
659 | /* initialize private data (optional) */ | |
6687e988 | 660 | void (*init)(struct sock *sk); |
317a76f9 | 661 | /* cleanup private data (optional) */ |
6687e988 | 662 | void (*release)(struct sock *sk); |
317a76f9 SH |
663 | |
664 | /* return slow start threshold (required) */ | |
6687e988 | 665 | u32 (*ssthresh)(struct sock *sk); |
317a76f9 | 666 | /* lower bound for congestion window (optional) */ |
72dc5b92 | 667 | u32 (*min_cwnd)(const struct sock *sk); |
317a76f9 | 668 | /* do new cwnd calculation (required) */ |
c3a05c60 | 669 | void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight); |
317a76f9 | 670 | /* call before changing ca_state (optional) */ |
6687e988 | 671 | void (*set_state)(struct sock *sk, u8 new_state); |
317a76f9 | 672 | /* call when cwnd event occurs (optional) */ |
6687e988 | 673 | void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); |
317a76f9 | 674 | /* new value of cwnd after loss (optional) */ |
6687e988 | 675 | u32 (*undo_cwnd)(struct sock *sk); |
317a76f9 | 676 | /* hook for packet ack accounting (optional) */ |
30cfd0ba | 677 | void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us); |
73c1f4a0 | 678 | /* get info for inet_diag (optional) */ |
6687e988 | 679 | void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb); |
317a76f9 SH |
680 | |
681 | char name[TCP_CA_NAME_MAX]; | |
682 | struct module *owner; | |
683 | }; | |
684 | ||
685 | extern int tcp_register_congestion_control(struct tcp_congestion_ops *type); | |
686 | extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); | |
687 | ||
6687e988 ACM |
688 | extern void tcp_init_congestion_control(struct sock *sk); |
689 | extern void tcp_cleanup_congestion_control(struct sock *sk); | |
317a76f9 SH |
690 | extern int tcp_set_default_congestion_control(const char *name); |
691 | extern void tcp_get_default_congestion_control(char *name); | |
3ff825b2 | 692 | extern void tcp_get_available_congestion_control(char *buf, size_t len); |
ce7bc3bf SH |
693 | extern void tcp_get_allowed_congestion_control(char *buf, size_t len); |
694 | extern int tcp_set_allowed_congestion_control(char *allowed); | |
6687e988 | 695 | extern int tcp_set_congestion_control(struct sock *sk, const char *name); |
40efc6fa | 696 | extern void tcp_slow_start(struct tcp_sock *tp); |
758ce5c8 | 697 | extern void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w); |
317a76f9 | 698 | |
5f8ef48d | 699 | extern struct tcp_congestion_ops tcp_init_congestion_ops; |
6687e988 | 700 | extern u32 tcp_reno_ssthresh(struct sock *sk); |
c3a05c60 | 701 | extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight); |
72dc5b92 | 702 | extern u32 tcp_reno_min_cwnd(const struct sock *sk); |
a8acfbac | 703 | extern struct tcp_congestion_ops tcp_reno; |
317a76f9 | 704 | |
6687e988 | 705 | static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state) |
317a76f9 | 706 | { |
6687e988 ACM |
707 | struct inet_connection_sock *icsk = inet_csk(sk); |
708 | ||
709 | if (icsk->icsk_ca_ops->set_state) | |
710 | icsk->icsk_ca_ops->set_state(sk, ca_state); | |
711 | icsk->icsk_ca_state = ca_state; | |
317a76f9 SH |
712 | } |
713 | ||
6687e988 | 714 | static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) |
317a76f9 | 715 | { |
6687e988 ACM |
716 | const struct inet_connection_sock *icsk = inet_csk(sk); |
717 | ||
718 | if (icsk->icsk_ca_ops->cwnd_event) | |
719 | icsk->icsk_ca_ops->cwnd_event(sk, event); | |
317a76f9 SH |
720 | } |
721 | ||
e60402d0 IJ |
722 | /* These functions determine how the current flow behaves in respect of SACK |
723 | * handling. SACK is negotiated with the peer, and therefore it can vary | |
724 | * between different flows. | |
725 | * | |
726 | * tcp_is_sack - SACK enabled | |
727 | * tcp_is_reno - No SACK | |
728 | * tcp_is_fack - FACK enabled, implies SACK enabled | |
729 | */ | |
730 | static inline int tcp_is_sack(const struct tcp_sock *tp) | |
731 | { | |
732 | return tp->rx_opt.sack_ok; | |
733 | } | |
734 | ||
735 | static inline int tcp_is_reno(const struct tcp_sock *tp) | |
736 | { | |
737 | return !tcp_is_sack(tp); | |
738 | } | |
739 | ||
740 | static inline int tcp_is_fack(const struct tcp_sock *tp) | |
741 | { | |
742 | return tp->rx_opt.sack_ok & 2; | |
743 | } | |
744 | ||
745 | static inline void tcp_enable_fack(struct tcp_sock *tp) | |
746 | { | |
747 | tp->rx_opt.sack_ok |= 2; | |
748 | } | |
749 | ||
83ae4088 IJ |
750 | static inline unsigned int tcp_left_out(const struct tcp_sock *tp) |
751 | { | |
752 | return tp->sacked_out + tp->lost_out; | |
753 | } | |
754 | ||
1da177e4 LT |
755 | /* This determines how many packets are "in the network" to the best |
756 | * of our knowledge. In many cases it is conservative, but where | |
757 | * detailed information is available from the receiver (via SACK | |
758 | * blocks etc.) we can make more aggressive calculations. | |
759 | * | |
760 | * Use this for decisions involving congestion control, use just | |
761 | * tp->packets_out to determine if the send queue is empty or not. | |
762 | * | |
763 | * Read this equation as: | |
764 | * | |
765 | * "Packets sent once on transmission queue" MINUS | |
766 | * "Packets left network, but not honestly ACKed yet" PLUS | |
767 | * "Packets fast retransmitted" | |
768 | */ | |
40efc6fa | 769 | static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) |
1da177e4 | 770 | { |
83ae4088 | 771 | return tp->packets_out - tcp_left_out(tp) + tp->retrans_out; |
1da177e4 LT |
772 | } |
773 | ||
0b6a05c1 IJ |
774 | #define TCP_INFINITE_SSTHRESH 0x7fffffff |
775 | ||
776 | static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp) | |
777 | { | |
778 | return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH; | |
779 | } | |
780 | ||
1da177e4 LT |
781 | /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. |
782 | * The exception is rate halving phase, when cwnd is decreasing towards | |
783 | * ssthresh. | |
784 | */ | |
6687e988 | 785 | static inline __u32 tcp_current_ssthresh(const struct sock *sk) |
1da177e4 | 786 | { |
6687e988 ACM |
787 | const struct tcp_sock *tp = tcp_sk(sk); |
788 | if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery)) | |
1da177e4 LT |
789 | return tp->snd_ssthresh; |
790 | else | |
791 | return max(tp->snd_ssthresh, | |
792 | ((tp->snd_cwnd >> 1) + | |
793 | (tp->snd_cwnd >> 2))); | |
794 | } | |
795 | ||
b9c4595b IJ |
796 | /* Use define here intentionally to get WARN_ON location shown at the caller */ |
797 | #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out) | |
1da177e4 | 798 | |
22b71c8f GR |
799 | /* |
800 | * Convert RFC 3390 larger initial window into an equivalent number of packets. | |
3d5b99ae | 801 | * This is based on the numbers specified in RFC 5681, 3.1. |
22b71c8f GR |
802 | */ |
803 | static inline u32 rfc3390_bytes_to_packets(const u32 smss) | |
804 | { | |
3d5b99ae | 805 | return smss <= 1095 ? 4 : (smss > 2190 ? 2 : 3); |
22b71c8f GR |
806 | } |
807 | ||
3cfe3baa | 808 | extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh); |
1da177e4 LT |
809 | extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst); |
810 | ||
811 | /* Slow start with delack produces 3 packets of burst, so that | |
dd9e0dda JH |
812 | * it is safe "de facto". This will be the default - same as |
813 | * the default reordering threshold - but if reordering increases, | |
814 | * we must be able to allow cwnd to burst at least this much in order | |
815 | * to not pull it back when holes are filled. | |
1da177e4 LT |
816 | */ |
817 | static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp) | |
818 | { | |
dd9e0dda | 819 | return tp->reordering; |
1da177e4 LT |
820 | } |
821 | ||
90840def IJ |
822 | /* Returns end sequence number of the receiver's advertised window */ |
823 | static inline u32 tcp_wnd_end(const struct tcp_sock *tp) | |
824 | { | |
825 | return tp->snd_una + tp->snd_wnd; | |
826 | } | |
cea14e0e | 827 | extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight); |
f4805ede | 828 | |
c1bd24b7 | 829 | static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss, |
40efc6fa | 830 | const struct sk_buff *skb) |
1da177e4 LT |
831 | { |
832 | if (skb->len < mss) | |
833 | tp->snd_sml = TCP_SKB_CB(skb)->end_seq; | |
834 | } | |
835 | ||
9e412ba7 | 836 | static inline void tcp_check_probe_timer(struct sock *sk) |
1da177e4 | 837 | { |
9e412ba7 | 838 | struct tcp_sock *tp = tcp_sk(sk); |
463c84b9 | 839 | const struct inet_connection_sock *icsk = inet_csk(sk); |
9e412ba7 | 840 | |
463c84b9 | 841 | if (!tp->packets_out && !icsk->icsk_pending) |
3f421baa ACM |
842 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0, |
843 | icsk->icsk_rto, TCP_RTO_MAX); | |
1da177e4 LT |
844 | } |
845 | ||
ee7537b6 | 846 | static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq) |
1da177e4 LT |
847 | { |
848 | tp->snd_wl1 = seq; | |
849 | } | |
850 | ||
ee7537b6 | 851 | static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq) |
1da177e4 LT |
852 | { |
853 | tp->snd_wl1 = seq; | |
854 | } | |
855 | ||
1da177e4 LT |
856 | /* |
857 | * Calculate(/check) TCP checksum | |
858 | */ | |
ba7808ea FD |
859 | static inline __sum16 tcp_v4_check(int len, __be32 saddr, |
860 | __be32 daddr, __wsum base) | |
1da177e4 LT |
861 | { |
862 | return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base); | |
863 | } | |
864 | ||
b51655b9 | 865 | static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb) |
1da177e4 | 866 | { |
fb286bb2 | 867 | return __skb_checksum_complete(skb); |
1da177e4 LT |
868 | } |
869 | ||
40efc6fa | 870 | static inline int tcp_checksum_complete(struct sk_buff *skb) |
1da177e4 | 871 | { |
60476372 | 872 | return !skb_csum_unnecessary(skb) && |
1da177e4 LT |
873 | __tcp_checksum_complete(skb); |
874 | } | |
875 | ||
876 | /* Prequeue for VJ style copy to user, combined with checksumming. */ | |
877 | ||
40efc6fa | 878 | static inline void tcp_prequeue_init(struct tcp_sock *tp) |
1da177e4 LT |
879 | { |
880 | tp->ucopy.task = NULL; | |
881 | tp->ucopy.len = 0; | |
882 | tp->ucopy.memory = 0; | |
883 | skb_queue_head_init(&tp->ucopy.prequeue); | |
97fc2f08 CL |
884 | #ifdef CONFIG_NET_DMA |
885 | tp->ucopy.dma_chan = NULL; | |
886 | tp->ucopy.wakeup = 0; | |
887 | tp->ucopy.pinned_list = NULL; | |
888 | tp->ucopy.dma_cookie = 0; | |
889 | #endif | |
1da177e4 LT |
890 | } |
891 | ||
892 | /* Packet is added to VJ-style prequeue for processing in process | |
893 | * context, if a reader task is waiting. Apparently, this exciting | |
894 | * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93) | |
895 | * failed somewhere. Latency? Burstiness? Well, at least now we will | |
896 | * see, why it failed. 8)8) --ANK | |
897 | * | |
898 | * NOTE: is this not too big to inline? | |
899 | */ | |
40efc6fa | 900 | static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb) |
1da177e4 LT |
901 | { |
902 | struct tcp_sock *tp = tcp_sk(sk); | |
903 | ||
f5f8d86b ED |
904 | if (sysctl_tcp_low_latency || !tp->ucopy.task) |
905 | return 0; | |
906 | ||
907 | __skb_queue_tail(&tp->ucopy.prequeue, skb); | |
908 | tp->ucopy.memory += skb->truesize; | |
909 | if (tp->ucopy.memory > sk->sk_rcvbuf) { | |
910 | struct sk_buff *skb1; | |
911 | ||
912 | BUG_ON(sock_owned_by_user(sk)); | |
913 | ||
914 | while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) { | |
915 | sk_backlog_rcv(sk, skb1); | |
916 | NET_INC_STATS_BH(sock_net(sk), | |
917 | LINUX_MIB_TCPPREQUEUEDROPPED); | |
1da177e4 | 918 | } |
f5f8d86b ED |
919 | |
920 | tp->ucopy.memory = 0; | |
921 | } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) { | |
aa395145 | 922 | wake_up_interruptible_sync_poll(sk_sleep(sk), |
7aedec2a | 923 | POLLIN | POLLRDNORM | POLLRDBAND); |
f5f8d86b ED |
924 | if (!inet_csk_ack_scheduled(sk)) |
925 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, | |
22f6dacd | 926 | (3 * tcp_rto_min(sk)) / 4, |
f5f8d86b | 927 | TCP_RTO_MAX); |
1da177e4 | 928 | } |
f5f8d86b | 929 | return 1; |
1da177e4 LT |
930 | } |
931 | ||
932 | ||
933 | #undef STATE_TRACE | |
934 | ||
935 | #ifdef STATE_TRACE | |
936 | static const char *statename[]={ | |
937 | "Unused","Established","Syn Sent","Syn Recv", | |
938 | "Fin Wait 1","Fin Wait 2","Time Wait", "Close", | |
939 | "Close Wait","Last ACK","Listen","Closing" | |
940 | }; | |
941 | #endif | |
490d5046 | 942 | extern void tcp_set_state(struct sock *sk, int state); |
1da177e4 | 943 | |
4ac02bab | 944 | extern void tcp_done(struct sock *sk); |
1da177e4 | 945 | |
40efc6fa | 946 | static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) |
1da177e4 LT |
947 | { |
948 | rx_opt->dsack = 0; | |
1da177e4 LT |
949 | rx_opt->num_sacks = 0; |
950 | } | |
951 | ||
1da177e4 LT |
952 | /* Determine a window scaling and initial window to offer. */ |
953 | extern void tcp_select_initial_window(int __space, __u32 mss, | |
954 | __u32 *rcv_wnd, __u32 *window_clamp, | |
31d12926 | 955 | int wscale_ok, __u8 *rcv_wscale, |
956 | __u32 init_rcv_wnd); | |
1da177e4 LT |
957 | |
958 | static inline int tcp_win_from_space(int space) | |
959 | { | |
960 | return sysctl_tcp_adv_win_scale<=0 ? | |
961 | (space>>(-sysctl_tcp_adv_win_scale)) : | |
962 | space - (space>>sysctl_tcp_adv_win_scale); | |
963 | } | |
964 | ||
965 | /* Note: caller must be prepared to deal with negative returns */ | |
966 | static inline int tcp_space(const struct sock *sk) | |
967 | { | |
968 | return tcp_win_from_space(sk->sk_rcvbuf - | |
969 | atomic_read(&sk->sk_rmem_alloc)); | |
970 | } | |
971 | ||
972 | static inline int tcp_full_space(const struct sock *sk) | |
973 | { | |
974 | return tcp_win_from_space(sk->sk_rcvbuf); | |
975 | } | |
976 | ||
40efc6fa SH |
977 | static inline void tcp_openreq_init(struct request_sock *req, |
978 | struct tcp_options_received *rx_opt, | |
979 | struct sk_buff *skb) | |
1da177e4 | 980 | { |
2e6599cb ACM |
981 | struct inet_request_sock *ireq = inet_rsk(req); |
982 | ||
1da177e4 | 983 | req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */ |
4dfc2817 | 984 | req->cookie_ts = 0; |
2e6599cb | 985 | tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq; |
1da177e4 LT |
986 | req->mss = rx_opt->mss_clamp; |
987 | req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0; | |
2e6599cb ACM |
988 | ireq->tstamp_ok = rx_opt->tstamp_ok; |
989 | ireq->sack_ok = rx_opt->sack_ok; | |
990 | ireq->snd_wscale = rx_opt->snd_wscale; | |
991 | ireq->wscale_ok = rx_opt->wscale_ok; | |
992 | ireq->acked = 0; | |
993 | ireq->ecn_ok = 0; | |
aa8223c7 | 994 | ireq->rmt_port = tcp_hdr(skb)->source; |
a3116ac5 | 995 | ireq->loc_port = tcp_hdr(skb)->dest; |
1da177e4 LT |
996 | } |
997 | ||
5c52ba17 | 998 | extern void tcp_enter_memory_pressure(struct sock *sk); |
1da177e4 | 999 | |
1da177e4 LT |
1000 | static inline int keepalive_intvl_when(const struct tcp_sock *tp) |
1001 | { | |
1002 | return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl; | |
1003 | } | |
1004 | ||
1005 | static inline int keepalive_time_when(const struct tcp_sock *tp) | |
1006 | { | |
1007 | return tp->keepalive_time ? : sysctl_tcp_keepalive_time; | |
1008 | } | |
1009 | ||
df19a626 ED |
1010 | static inline int keepalive_probes(const struct tcp_sock *tp) |
1011 | { | |
1012 | return tp->keepalive_probes ? : sysctl_tcp_keepalive_probes; | |
1013 | } | |
1014 | ||
6c37e5de FL |
1015 | static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp) |
1016 | { | |
1017 | const struct inet_connection_sock *icsk = &tp->inet_conn; | |
1018 | ||
1019 | return min_t(u32, tcp_time_stamp - icsk->icsk_ack.lrcvtime, | |
1020 | tcp_time_stamp - tp->rcv_tstamp); | |
1021 | } | |
1022 | ||
463c84b9 | 1023 | static inline int tcp_fin_time(const struct sock *sk) |
1da177e4 | 1024 | { |
463c84b9 ACM |
1025 | int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout; |
1026 | const int rto = inet_csk(sk)->icsk_rto; | |
1da177e4 | 1027 | |
463c84b9 ACM |
1028 | if (fin_timeout < (rto << 2) - (rto >> 1)) |
1029 | fin_timeout = (rto << 2) - (rto >> 1); | |
1da177e4 LT |
1030 | |
1031 | return fin_timeout; | |
1032 | } | |
1033 | ||
c887e6d2 IJ |
1034 | static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, |
1035 | int paws_win) | |
1da177e4 | 1036 | { |
c887e6d2 IJ |
1037 | if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) |
1038 | return 1; | |
1039 | if (unlikely(get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)) | |
1040 | return 1; | |
bc2ce894 ED |
1041 | /* |
1042 | * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0, | |
1043 | * then following tcp messages have valid values. Ignore 0 value, | |
1044 | * or else 'negative' tsval might forbid us to accept their packets. | |
1045 | */ | |
1046 | if (!rx_opt->ts_recent) | |
1047 | return 1; | |
c887e6d2 IJ |
1048 | return 0; |
1049 | } | |
1050 | ||
1051 | static inline int tcp_paws_reject(const struct tcp_options_received *rx_opt, | |
1052 | int rst) | |
1053 | { | |
1054 | if (tcp_paws_check(rx_opt, 0)) | |
1da177e4 LT |
1055 | return 0; |
1056 | ||
1057 | /* RST segments are not recommended to carry timestamp, | |
1058 | and, if they do, it is recommended to ignore PAWS because | |
1059 | "their cleanup function should take precedence over timestamps." | |
1060 | Certainly, it is mistake. It is necessary to understand the reasons | |
1061 | of this constraint to relax it: if peer reboots, clock may go | |
1062 | out-of-sync and half-open connections will not be reset. | |
1063 | Actually, the problem would be not existing if all | |
1064 | the implementations followed draft about maintaining clock | |
1065 | via reboots. Linux-2.2 DOES NOT! | |
1066 | ||
1067 | However, we can relax time bounds for RST segments to MSL. | |
1068 | */ | |
9d729f72 | 1069 | if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL) |
1da177e4 LT |
1070 | return 0; |
1071 | return 1; | |
1072 | } | |
1073 | ||
1da177e4 LT |
1074 | #define TCP_CHECK_TIMER(sk) do { } while (0) |
1075 | ||
a9c19329 | 1076 | static inline void tcp_mib_init(struct net *net) |
1da177e4 LT |
1077 | { |
1078 | /* See RFC 2012 */ | |
cf1100a7 PE |
1079 | TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1); |
1080 | TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); | |
1081 | TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); | |
1082 | TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1); | |
1da177e4 LT |
1083 | } |
1084 | ||
5af4ec23 | 1085 | /* from STCP */ |
ef9da47c | 1086 | static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) |
0800f170 | 1087 | { |
6a438bbe SH |
1088 | tp->lost_skb_hint = NULL; |
1089 | tp->scoreboard_skb_hint = NULL; | |
ef9da47c IJ |
1090 | } |
1091 | ||
1092 | static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) | |
1093 | { | |
1094 | tcp_clear_retrans_hints_partial(tp); | |
6a438bbe | 1095 | tp->retransmit_skb_hint = NULL; |
b7689205 IJ |
1096 | } |
1097 | ||
cfb6eeb4 YH |
1098 | /* MD5 Signature */ |
1099 | struct crypto_hash; | |
1100 | ||
1101 | /* - key database */ | |
1102 | struct tcp_md5sig_key { | |
1103 | u8 *key; | |
1104 | u8 keylen; | |
1105 | }; | |
1106 | ||
1107 | struct tcp4_md5sig_key { | |
f8ab18d2 | 1108 | struct tcp_md5sig_key base; |
cfb6eeb4 YH |
1109 | __be32 addr; |
1110 | }; | |
1111 | ||
1112 | struct tcp6_md5sig_key { | |
f8ab18d2 | 1113 | struct tcp_md5sig_key base; |
cfb6eeb4 YH |
1114 | #if 0 |
1115 | u32 scope_id; /* XXX */ | |
1116 | #endif | |
1117 | struct in6_addr addr; | |
1118 | }; | |
1119 | ||
1120 | /* - sock block */ | |
1121 | struct tcp_md5sig_info { | |
1122 | struct tcp4_md5sig_key *keys4; | |
1123 | #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) | |
1124 | struct tcp6_md5sig_key *keys6; | |
1125 | u32 entries6; | |
1126 | u32 alloced6; | |
1127 | #endif | |
1128 | u32 entries4; | |
1129 | u32 alloced4; | |
1130 | }; | |
1131 | ||
1132 | /* - pseudo header */ | |
1133 | struct tcp4_pseudohdr { | |
1134 | __be32 saddr; | |
1135 | __be32 daddr; | |
1136 | __u8 pad; | |
1137 | __u8 protocol; | |
1138 | __be16 len; | |
1139 | }; | |
1140 | ||
1141 | struct tcp6_pseudohdr { | |
1142 | struct in6_addr saddr; | |
1143 | struct in6_addr daddr; | |
1144 | __be32 len; | |
1145 | __be32 protocol; /* including padding */ | |
1146 | }; | |
1147 | ||
1148 | union tcp_md5sum_block { | |
1149 | struct tcp4_pseudohdr ip4; | |
1150 | #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) | |
1151 | struct tcp6_pseudohdr ip6; | |
1152 | #endif | |
1153 | }; | |
1154 | ||
1155 | /* - pool: digest algorithm, hash description and scratch buffer */ | |
1156 | struct tcp_md5sig_pool { | |
1157 | struct hash_desc md5_desc; | |
1158 | union tcp_md5sum_block md5_blk; | |
1159 | }; | |
1160 | ||
cfb6eeb4 | 1161 | /* - functions */ |
53d3176b CG |
1162 | extern int tcp_v4_md5_hash_skb(char *md5_hash, struct tcp_md5sig_key *key, |
1163 | struct sock *sk, struct request_sock *req, | |
1164 | struct sk_buff *skb); | |
1165 | extern struct tcp_md5sig_key * tcp_v4_md5_lookup(struct sock *sk, | |
1166 | struct sock *addr_sk); | |
1167 | extern int tcp_v4_md5_do_add(struct sock *sk, __be32 addr, u8 *newkey, | |
1168 | u8 newkeylen); | |
1169 | extern int tcp_v4_md5_do_del(struct sock *sk, __be32 addr); | |
cfb6eeb4 | 1170 | |
9501f972 YH |
1171 | #ifdef CONFIG_TCP_MD5SIG |
1172 | #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \ | |
1173 | &(struct tcp_md5sig_key) { \ | |
1174 | .key = (twsk)->tw_md5_key, \ | |
1175 | .keylen = (twsk)->tw_md5_keylen, \ | |
1176 | } : NULL) | |
1177 | #else | |
1178 | #define tcp_twsk_md5_key(twsk) NULL | |
1179 | #endif | |
1180 | ||
7d720c3e | 1181 | extern struct tcp_md5sig_pool * __percpu *tcp_alloc_md5sig_pool(struct sock *); |
53d3176b | 1182 | extern void tcp_free_md5sig_pool(void); |
cfb6eeb4 | 1183 | |
35790c04 | 1184 | extern struct tcp_md5sig_pool *tcp_get_md5sig_pool(void); |
53d3176b | 1185 | extern void tcp_put_md5sig_pool(void); |
35790c04 | 1186 | |
49a72dfb AL |
1187 | extern int tcp_md5_hash_header(struct tcp_md5sig_pool *, struct tcphdr *); |
1188 | extern int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, struct sk_buff *, | |
1189 | unsigned header_len); | |
1190 | extern int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, | |
1191 | struct tcp_md5sig_key *key); | |
cfb6eeb4 | 1192 | |
fe067e8a DM |
1193 | /* write queue abstraction */ |
1194 | static inline void tcp_write_queue_purge(struct sock *sk) | |
1195 | { | |
1196 | struct sk_buff *skb; | |
1197 | ||
1198 | while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) | |
3ab224be HA |
1199 | sk_wmem_free_skb(sk, skb); |
1200 | sk_mem_reclaim(sk); | |
8818a9d8 | 1201 | tcp_clear_all_retrans_hints(tcp_sk(sk)); |
fe067e8a DM |
1202 | } |
1203 | ||
1204 | static inline struct sk_buff *tcp_write_queue_head(struct sock *sk) | |
1205 | { | |
cd07a8ea | 1206 | return skb_peek(&sk->sk_write_queue); |
fe067e8a DM |
1207 | } |
1208 | ||
1209 | static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk) | |
1210 | { | |
cd07a8ea | 1211 | return skb_peek_tail(&sk->sk_write_queue); |
fe067e8a DM |
1212 | } |
1213 | ||
1214 | static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb) | |
1215 | { | |
cd07a8ea | 1216 | return skb_queue_next(&sk->sk_write_queue, skb); |
fe067e8a DM |
1217 | } |
1218 | ||
832d11c5 IJ |
1219 | static inline struct sk_buff *tcp_write_queue_prev(struct sock *sk, struct sk_buff *skb) |
1220 | { | |
1221 | return skb_queue_prev(&sk->sk_write_queue, skb); | |
1222 | } | |
1223 | ||
fe067e8a | 1224 | #define tcp_for_write_queue(skb, sk) \ |
cd07a8ea | 1225 | skb_queue_walk(&(sk)->sk_write_queue, skb) |
fe067e8a DM |
1226 | |
1227 | #define tcp_for_write_queue_from(skb, sk) \ | |
cd07a8ea | 1228 | skb_queue_walk_from(&(sk)->sk_write_queue, skb) |
fe067e8a | 1229 | |
234b6860 | 1230 | #define tcp_for_write_queue_from_safe(skb, tmp, sk) \ |
cd07a8ea | 1231 | skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp) |
234b6860 | 1232 | |
fe067e8a DM |
1233 | static inline struct sk_buff *tcp_send_head(struct sock *sk) |
1234 | { | |
1235 | return sk->sk_send_head; | |
1236 | } | |
1237 | ||
cd07a8ea DM |
1238 | static inline bool tcp_skb_is_last(const struct sock *sk, |
1239 | const struct sk_buff *skb) | |
1240 | { | |
1241 | return skb_queue_is_last(&sk->sk_write_queue, skb); | |
1242 | } | |
1243 | ||
fe067e8a DM |
1244 | static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb) |
1245 | { | |
cd07a8ea | 1246 | if (tcp_skb_is_last(sk, skb)) |
fe067e8a | 1247 | sk->sk_send_head = NULL; |
cd07a8ea DM |
1248 | else |
1249 | sk->sk_send_head = tcp_write_queue_next(sk, skb); | |
fe067e8a DM |
1250 | } |
1251 | ||
1252 | static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked) | |
1253 | { | |
1254 | if (sk->sk_send_head == skb_unlinked) | |
1255 | sk->sk_send_head = NULL; | |
1256 | } | |
1257 | ||
1258 | static inline void tcp_init_send_head(struct sock *sk) | |
1259 | { | |
1260 | sk->sk_send_head = NULL; | |
1261 | } | |
1262 | ||
1263 | static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) | |
1264 | { | |
1265 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
1266 | } | |
1267 | ||
1268 | static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) | |
1269 | { | |
1270 | __tcp_add_write_queue_tail(sk, skb); | |
1271 | ||
1272 | /* Queue it, remembering where we must start sending. */ | |
6859d494 | 1273 | if (sk->sk_send_head == NULL) { |
fe067e8a | 1274 | sk->sk_send_head = skb; |
6859d494 IJ |
1275 | |
1276 | if (tcp_sk(sk)->highest_sack == NULL) | |
1277 | tcp_sk(sk)->highest_sack = skb; | |
1278 | } | |
fe067e8a DM |
1279 | } |
1280 | ||
1281 | static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb) | |
1282 | { | |
1283 | __skb_queue_head(&sk->sk_write_queue, skb); | |
1284 | } | |
1285 | ||
1286 | /* Insert buff after skb on the write queue of sk. */ | |
1287 | static inline void tcp_insert_write_queue_after(struct sk_buff *skb, | |
1288 | struct sk_buff *buff, | |
1289 | struct sock *sk) | |
1290 | { | |
7de6c033 | 1291 | __skb_queue_after(&sk->sk_write_queue, skb, buff); |
fe067e8a DM |
1292 | } |
1293 | ||
43f59c89 | 1294 | /* Insert new before skb on the write queue of sk. */ |
fe067e8a DM |
1295 | static inline void tcp_insert_write_queue_before(struct sk_buff *new, |
1296 | struct sk_buff *skb, | |
1297 | struct sock *sk) | |
1298 | { | |
43f59c89 | 1299 | __skb_queue_before(&sk->sk_write_queue, skb, new); |