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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 | * | |
10 | * Authors: Ross Biro | |
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 | ||
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> | |
29 | #include <linux/skbuff.h> | |
30 | #include <linux/dmaengine.h> | |
31 | #include <linux/crypto.h> | |
32 | #include <linux/cryptohash.h> | |
33 | #include <linux/kref.h> | |
34 | ||
35 | #include <net/inet_connection_sock.h> | |
36 | #include <net/inet_timewait_sock.h> | |
37 | #include <net/inet_hashtables.h> | |
38 | #include <net/checksum.h> | |
39 | #include <net/request_sock.h> | |
40 | #include <net/sock.h> | |
41 | #include <net/snmp.h> | |
42 | #include <net/ip.h> | |
43 | #include <net/tcp_states.h> | |
44 | #include <net/inet_ecn.h> | |
45 | #include <net/dst.h> | |
46 | ||
47 | #include <linux/seq_file.h> | |
48 | ||
49 | extern struct inet_hashinfo tcp_hashinfo; | |
50 | ||
51 | extern struct percpu_counter tcp_orphan_count; | |
52 | extern void tcp_time_wait(struct sock *sk, int state, int timeo); | |
53 | ||
54 | #define MAX_TCP_HEADER (128 + MAX_HEADER) | |
55 | #define MAX_TCP_OPTION_SPACE 40 | |
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 | ||
66 | /* The least MTU to use for probing */ | |
67 | #define TCP_BASE_MSS 512 | |
68 | ||
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 | |
98 | * connection: ~180sec is RFC minimum */ | |
99 | ||
100 | #define TCP_SYNACK_RETRIES 5 /* number of times to retry passive opening a | |
101 | * connection: ~180sec is RFC minimum */ | |
102 | ||
103 | ||
104 | #define TCP_ORPHAN_RETRIES 7 /* number of times to retry on an orphaned | |
105 | * socket. 7 is ~50sec-16min. | |
106 | */ | |
107 | ||
108 | ||
109 | #define TCP_TIMEWAIT_LEN (60*HZ) /* how long to wait to destroy TIME-WAIT | |
110 | * state, about 60 seconds */ | |
111 | #define TCP_FIN_TIMEOUT TCP_TIMEWAIT_LEN | |
112 | /* BSD style FIN_WAIT2 deadlock breaker. | |
113 | * It used to be 3min, new value is 60sec, | |
114 | * to combine FIN-WAIT-2 timeout with | |
115 | * TIME-WAIT timer. | |
116 | */ | |
117 | ||
118 | #define TCP_DELACK_MAX ((unsigned)(HZ/5)) /* maximal time to delay before sending an ACK */ | |
119 | #if HZ >= 100 | |
120 | #define TCP_DELACK_MIN ((unsigned)(HZ/25)) /* minimal time to delay before sending an ACK */ | |
121 | #define TCP_ATO_MIN ((unsigned)(HZ/25)) | |
122 | #else | |
123 | #define TCP_DELACK_MIN 4U | |
124 | #define TCP_ATO_MIN 4U | |
125 | #endif | |
126 | #define TCP_RTO_MAX ((unsigned)(120*HZ)) | |
127 | #define TCP_RTO_MIN ((unsigned)(HZ/5)) | |
128 | #define TCP_TIMEOUT_INIT ((unsigned)(3*HZ)) /* RFC 1122 initial RTO value */ | |
129 | ||
130 | #define TCP_RESOURCE_PROBE_INTERVAL ((unsigned)(HZ/2U)) /* Maximal interval between probes | |
131 | * for local resources. | |
132 | */ | |
133 | ||
134 | #define TCP_KEEPALIVE_TIME (120*60*HZ) /* two hours */ | |
135 | #define TCP_KEEPALIVE_PROBES 9 /* Max of 9 keepalive probes */ | |
136 | #define TCP_KEEPALIVE_INTVL (75*HZ) | |
137 | ||
138 | #define MAX_TCP_KEEPIDLE 32767 | |
139 | #define MAX_TCP_KEEPINTVL 32767 | |
140 | #define MAX_TCP_KEEPCNT 127 | |
141 | #define MAX_TCP_SYNCNT 127 | |
142 | ||
143 | #define TCP_SYNQ_INTERVAL (HZ/5) /* Period of SYNACK timer */ | |
144 | ||
145 | #define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) | |
146 | #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated | |
147 | * after this time. It should be equal | |
148 | * (or greater than) TCP_TIMEWAIT_LEN | |
149 | * to provide reliability equal to one | |
150 | * provided by timewait state. | |
151 | */ | |
152 | #define TCP_PAWS_WINDOW 1 /* Replay window for per-host | |
153 | * timestamps. It must be less than | |
154 | * minimal timewait lifetime. | |
155 | */ | |
156 | /* | |
157 | * TCP option | |
158 | */ | |
159 | ||
160 | #define TCPOPT_NOP 1 /* Padding */ | |
161 | #define TCPOPT_EOL 0 /* End of options */ | |
162 | #define TCPOPT_MSS 2 /* Segment size negotiating */ | |
163 | #define TCPOPT_WINDOW 3 /* Window scaling */ | |
164 | #define TCPOPT_SACK_PERM 4 /* SACK Permitted */ | |
165 | #define TCPOPT_SACK 5 /* SACK Block */ | |
166 | #define TCPOPT_TIMESTAMP 8 /* Better RTT estimations/PAWS */ | |
167 | #define TCPOPT_MD5SIG 19 /* MD5 Signature (RFC2385) */ | |
168 | #define TCPOPT_COOKIE 253 /* Cookie extension (experimental) */ | |
169 | ||
170 | /* | |
171 | * TCP option lengths | |
172 | */ | |
173 | ||
174 | #define TCPOLEN_MSS 4 | |
175 | #define TCPOLEN_WINDOW 3 | |
176 | #define TCPOLEN_SACK_PERM 2 | |
177 | #define TCPOLEN_TIMESTAMP 10 | |
178 | #define TCPOLEN_MD5SIG 18 | |
179 | #define TCPOLEN_COOKIE_BASE 2 /* Cookie-less header extension */ | |
180 | #define TCPOLEN_COOKIE_PAIR 3 /* Cookie pair header extension */ | |
181 | #define TCPOLEN_COOKIE_MIN (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MIN) | |
182 | #define TCPOLEN_COOKIE_MAX (TCPOLEN_COOKIE_BASE+TCP_COOKIE_MAX) | |
183 | ||
184 | /* But this is what stacks really send out. */ | |
185 | #define TCPOLEN_TSTAMP_ALIGNED 12 | |
186 | #define TCPOLEN_WSCALE_ALIGNED 4 | |
187 | #define TCPOLEN_SACKPERM_ALIGNED 4 | |
188 | #define TCPOLEN_SACK_BASE 2 | |
189 | #define TCPOLEN_SACK_BASE_ALIGNED 4 | |
190 | #define TCPOLEN_SACK_PERBLOCK 8 | |
191 | #define TCPOLEN_MD5SIG_ALIGNED 20 | |
192 | #define TCPOLEN_MSS_ALIGNED 4 | |
193 | ||
194 | /* Flags in tp->nonagle */ | |
195 | #define TCP_NAGLE_OFF 1 /* Nagle's algo is disabled */ | |
196 | #define TCP_NAGLE_CORK 2 /* Socket is corked */ | |
197 | #define TCP_NAGLE_PUSH 4 /* Cork is overridden for already queued data */ | |
198 | ||
199 | /* TCP thin-stream limits */ | |
200 | #define TCP_THIN_LINEAR_RETRIES 6 /* After 6 linear retries, do exp. backoff */ | |
201 | ||
202 | extern struct inet_timewait_death_row tcp_death_row; | |
203 | ||
204 | /* sysctl variables for tcp */ | |
205 | extern int sysctl_tcp_timestamps; | |
206 | extern int sysctl_tcp_window_scaling; | |
207 | extern int sysctl_tcp_sack; | |
208 | extern int sysctl_tcp_fin_timeout; | |
209 | extern int sysctl_tcp_keepalive_time; | |
210 | extern int sysctl_tcp_keepalive_probes; | |
211 | extern int sysctl_tcp_keepalive_intvl; | |
212 | extern int sysctl_tcp_syn_retries; | |
213 | extern int sysctl_tcp_synack_retries; | |
214 | extern int sysctl_tcp_retries1; | |
215 | extern int sysctl_tcp_retries2; | |
216 | extern int sysctl_tcp_orphan_retries; | |
217 | extern int sysctl_tcp_syncookies; | |
218 | extern int sysctl_tcp_retrans_collapse; | |
219 | extern int sysctl_tcp_stdurg; | |
220 | extern int sysctl_tcp_rfc1337; | |
221 | extern int sysctl_tcp_abort_on_overflow; | |
222 | extern int sysctl_tcp_max_orphans; | |
223 | extern int sysctl_tcp_fack; | |
224 | extern int sysctl_tcp_reordering; | |
225 | extern int sysctl_tcp_ecn; | |
226 | extern int sysctl_tcp_dsack; | |
227 | extern int sysctl_tcp_mem[3]; | |
228 | extern int sysctl_tcp_wmem[3]; | |
229 | extern int sysctl_tcp_rmem[3]; | |
230 | extern int sysctl_tcp_app_win; | |
231 | extern int sysctl_tcp_adv_win_scale; | |
232 | extern int sysctl_tcp_tw_reuse; | |
233 | extern int sysctl_tcp_frto; | |
234 | extern int sysctl_tcp_frto_response; | |
235 | extern int sysctl_tcp_low_latency; | |
236 | extern int sysctl_tcp_dma_copybreak; | |
237 | extern int sysctl_tcp_nometrics_save; | |
238 | extern int sysctl_tcp_moderate_rcvbuf; | |
239 | extern int sysctl_tcp_tso_win_divisor; | |
240 | extern int sysctl_tcp_abc; | |
241 | extern int sysctl_tcp_mtu_probing; | |
242 | extern int sysctl_tcp_base_mss; | |
243 | extern int sysctl_tcp_workaround_signed_windows; | |
244 | extern int sysctl_tcp_slow_start_after_idle; | |
245 | extern int sysctl_tcp_max_ssthresh; | |
246 | extern int sysctl_tcp_cookie_size; | |
247 | extern int sysctl_tcp_thin_linear_timeouts; | |
248 | extern int sysctl_tcp_thin_dupack; | |
249 | ||
250 | extern atomic_t tcp_memory_allocated; | |
251 | extern struct percpu_counter tcp_sockets_allocated; | |
252 | extern int tcp_memory_pressure; | |
253 | ||
254 | /* | |
255 | * The next routines deal with comparing 32 bit unsigned ints | |
256 | * and worry about wraparound (automatic with unsigned arithmetic). | |
257 | */ | |
258 | ||
259 | static inline int before(__u32 seq1, __u32 seq2) | |
260 | { | |
261 | return (__s32)(seq1-seq2) < 0; | |
262 | } | |
263 | #define after(seq2, seq1) before(seq1, seq2) | |
264 | ||
265 | /* is s2<=s1<=s3 ? */ | |
266 | static inline int between(__u32 seq1, __u32 seq2, __u32 seq3) | |
267 | { | |
268 | return seq3 - seq2 >= seq1 - seq2; | |
269 | } | |
270 | ||
271 | static inline int tcp_too_many_orphans(struct sock *sk, int num) | |
272 | { | |
273 | return (num > sysctl_tcp_max_orphans) || | |
274 | (sk->sk_wmem_queued > SOCK_MIN_SNDBUF && | |
275 | atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2]); | |
276 | } | |
277 | ||
278 | /* syncookies: remember time of last synqueue overflow */ | |
279 | static inline void tcp_synq_overflow(struct sock *sk) | |
280 | { | |
281 | tcp_sk(sk)->rx_opt.ts_recent_stamp = jiffies; | |
282 | } | |
283 | ||
284 | /* syncookies: no recent synqueue overflow on this listening socket? */ | |
285 | static inline int tcp_synq_no_recent_overflow(const struct sock *sk) | |
286 | { | |
287 | unsigned long last_overflow = tcp_sk(sk)->rx_opt.ts_recent_stamp; | |
288 | return time_after(jiffies, last_overflow + TCP_TIMEOUT_INIT); | |
289 | } | |
290 | ||
291 | extern struct proto tcp_prot; | |
292 | ||
293 | #define TCP_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.tcp_statistics, field) | |
294 | #define TCP_INC_STATS_BH(net, field) SNMP_INC_STATS_BH((net)->mib.tcp_statistics, field) | |
295 | #define TCP_DEC_STATS(net, field) SNMP_DEC_STATS((net)->mib.tcp_statistics, field) | |
296 | #define TCP_ADD_STATS_USER(net, field, val) SNMP_ADD_STATS_USER((net)->mib.tcp_statistics, field, val) | |
297 | ||
298 | extern void tcp_v4_err(struct sk_buff *skb, u32); | |
299 | ||
300 | extern void tcp_shutdown (struct sock *sk, int how); | |
301 | ||
302 | extern int tcp_v4_rcv(struct sk_buff *skb); | |
303 | ||
304 | extern int tcp_v4_remember_stamp(struct sock *sk); | |
305 | ||
306 | extern int tcp_v4_tw_remember_stamp(struct inet_timewait_sock *tw); | |
307 | ||
308 | extern int tcp_sendmsg(struct kiocb *iocb, struct socket *sock, | |
309 | struct msghdr *msg, size_t size); | |
310 | extern ssize_t tcp_sendpage(struct socket *sock, struct page *page, int offset, size_t size, int flags); | |
311 | ||
312 | extern int tcp_ioctl(struct sock *sk, | |
313 | int cmd, | |
314 | unsigned long arg); | |
315 | ||
316 | extern int tcp_rcv_state_process(struct sock *sk, | |
317 | struct sk_buff *skb, | |
318 | struct tcphdr *th, | |
319 | unsigned len); | |
320 | ||
321 | extern int tcp_rcv_established(struct sock *sk, | |
322 | struct sk_buff *skb, | |
323 | struct tcphdr *th, | |
324 | unsigned len); | |
325 | ||
326 | extern void tcp_rcv_space_adjust(struct sock *sk); | |
327 | ||
328 | extern void tcp_cleanup_rbuf(struct sock *sk, int copied); | |
329 | ||
330 | extern int tcp_twsk_unique(struct sock *sk, | |
331 | struct sock *sktw, void *twp); | |
332 | ||
333 | extern void tcp_twsk_destructor(struct sock *sk); | |
334 | ||
335 | extern ssize_t tcp_splice_read(struct socket *sk, loff_t *ppos, | |
336 | struct pipe_inode_info *pipe, size_t len, unsigned int flags); | |
337 | ||
338 | static inline void tcp_dec_quickack_mode(struct sock *sk, | |
339 | const unsigned int pkts) | |
340 | { | |
341 | struct inet_connection_sock *icsk = inet_csk(sk); | |
342 | ||
343 | if (icsk->icsk_ack.quick) { | |
344 | if (pkts >= icsk->icsk_ack.quick) { | |
345 | icsk->icsk_ack.quick = 0; | |
346 | /* Leaving quickack mode we deflate ATO. */ | |
347 | icsk->icsk_ack.ato = TCP_ATO_MIN; | |
348 | } else | |
349 | icsk->icsk_ack.quick -= pkts; | |
350 | } | |
351 | } | |
352 | ||
353 | extern void tcp_enter_quickack_mode(struct sock *sk); | |
354 | ||
355 | #define TCP_ECN_OK 1 | |
356 | #define TCP_ECN_QUEUE_CWR 2 | |
357 | #define TCP_ECN_DEMAND_CWR 4 | |
358 | ||
359 | static __inline__ void | |
360 | TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th) | |
361 | { | |
362 | if (sysctl_tcp_ecn && th->ece && th->cwr) | |
363 | inet_rsk(req)->ecn_ok = 1; | |
364 | } | |
365 | ||
366 | enum tcp_tw_status { | |
367 | TCP_TW_SUCCESS = 0, | |
368 | TCP_TW_RST = 1, | |
369 | TCP_TW_ACK = 2, | |
370 | TCP_TW_SYN = 3 | |
371 | }; | |
372 | ||
373 | ||
374 | extern enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, | |
375 | struct sk_buff *skb, | |
376 | const struct tcphdr *th); | |
377 | ||
378 | extern struct sock * tcp_check_req(struct sock *sk,struct sk_buff *skb, | |
379 | struct request_sock *req, | |
380 | struct request_sock **prev); | |
381 | extern int tcp_child_process(struct sock *parent, | |
382 | struct sock *child, | |
383 | struct sk_buff *skb); | |
384 | extern int tcp_use_frto(struct sock *sk); | |
385 | extern void tcp_enter_frto(struct sock *sk); | |
386 | extern void tcp_enter_loss(struct sock *sk, int how); | |
387 | extern void tcp_clear_retrans(struct tcp_sock *tp); | |
388 | extern void tcp_update_metrics(struct sock *sk); | |
389 | ||
390 | extern void tcp_close(struct sock *sk, | |
391 | long timeout); | |
392 | extern unsigned int tcp_poll(struct file * file, struct socket *sock, struct poll_table_struct *wait); | |
393 | ||
394 | extern int tcp_getsockopt(struct sock *sk, int level, | |
395 | int optname, | |
396 | char __user *optval, | |
397 | int __user *optlen); | |
398 | extern int tcp_setsockopt(struct sock *sk, int level, | |
399 | int optname, char __user *optval, | |
400 | unsigned int optlen); | |
401 | extern int compat_tcp_getsockopt(struct sock *sk, | |
402 | int level, int optname, | |
403 | char __user *optval, int __user *optlen); | |
404 | extern int compat_tcp_setsockopt(struct sock *sk, | |
405 | int level, int optname, | |
406 | char __user *optval, unsigned int optlen); | |
407 | extern void tcp_set_keepalive(struct sock *sk, int val); | |
408 | extern void tcp_syn_ack_timeout(struct sock *sk, | |
409 | struct request_sock *req); | |
410 | extern int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, | |
411 | struct msghdr *msg, | |
412 | size_t len, int nonblock, | |
413 | int flags, int *addr_len); | |
414 | ||
415 | extern void tcp_parse_options(struct sk_buff *skb, | |
416 | struct tcp_options_received *opt_rx, | |
417 | u8 **hvpp, | |
418 | int estab); | |
419 | ||
420 | extern u8 *tcp_parse_md5sig_option(struct tcphdr *th); | |
421 | ||
422 | /* | |
423 | * TCP v4 functions exported for the inet6 API | |
424 | */ | |
425 | ||
426 | extern void tcp_v4_send_check(struct sock *sk, int len, | |
427 | struct sk_buff *skb); | |
428 | ||
429 | extern int tcp_v4_conn_request(struct sock *sk, | |
430 | struct sk_buff *skb); | |
431 | ||
432 | extern struct sock * tcp_create_openreq_child(struct sock *sk, | |
433 | struct request_sock *req, | |
434 | struct sk_buff *skb); | |
435 | ||
436 | extern struct sock * tcp_v4_syn_recv_sock(struct sock *sk, | |
437 | struct sk_buff *skb, | |
438 | struct request_sock *req, | |
439 | struct dst_entry *dst); | |
440 | ||
441 | extern int tcp_v4_do_rcv(struct sock *sk, | |
442 | struct sk_buff *skb); | |
443 | ||
444 | extern int tcp_v4_connect(struct sock *sk, | |
445 | struct sockaddr *uaddr, | |
446 | int addr_len); | |
447 | ||
448 | extern int tcp_connect(struct sock *sk); | |
449 | ||
450 | extern struct sk_buff * tcp_make_synack(struct sock *sk, | |
451 | struct dst_entry *dst, | |
452 | struct request_sock *req, | |
453 | struct request_values *rvp); | |
454 | ||
455 | extern int tcp_disconnect(struct sock *sk, int flags); | |
456 | ||
457 | ||
458 | /* From syncookies.c */ | |
459 | extern __u32 syncookie_secret[2][16-4+SHA_DIGEST_WORDS]; | |
460 | extern struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, | |
461 | struct ip_options *opt); | |
462 | extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, | |
463 | __u16 *mss); | |
464 | ||
465 | extern __u32 cookie_init_timestamp(struct request_sock *req); | |
466 | extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt); | |
467 | ||
468 | /* From net/ipv6/syncookies.c */ | |
469 | extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb); | |
470 | extern __u32 cookie_v6_init_sequence(struct sock *sk, struct sk_buff *skb, | |
471 | __u16 *mss); | |
472 | ||
473 | /* tcp_output.c */ | |
474 | ||
475 | extern void __tcp_push_pending_frames(struct sock *sk, unsigned int cur_mss, | |
476 | int nonagle); | |
477 | extern int tcp_may_send_now(struct sock *sk); | |
478 | extern int tcp_retransmit_skb(struct sock *, struct sk_buff *); | |
479 | extern void tcp_retransmit_timer(struct sock *sk); | |
480 | extern void tcp_xmit_retransmit_queue(struct sock *); | |
481 | extern void tcp_simple_retransmit(struct sock *); | |
482 | extern int tcp_trim_head(struct sock *, struct sk_buff *, u32); | |
483 | extern int tcp_fragment(struct sock *, struct sk_buff *, u32, unsigned int); | |
484 | ||
485 | extern void tcp_send_probe0(struct sock *); | |
486 | extern void tcp_send_partial(struct sock *); | |
487 | extern int tcp_write_wakeup(struct sock *); | |
488 | extern void tcp_send_fin(struct sock *sk); | |
489 | extern void tcp_send_active_reset(struct sock *sk, gfp_t priority); | |
490 | extern int tcp_send_synack(struct sock *); | |
491 | extern void tcp_push_one(struct sock *, unsigned int mss_now); | |
492 | extern void tcp_send_ack(struct sock *sk); | |
493 | extern void tcp_send_delayed_ack(struct sock *sk); | |
494 | ||
495 | /* tcp_input.c */ | |
496 | extern void tcp_cwnd_application_limited(struct sock *sk); | |
497 | ||
498 | /* tcp_timer.c */ | |
499 | extern void tcp_init_xmit_timers(struct sock *); | |
500 | static inline void tcp_clear_xmit_timers(struct sock *sk) | |
501 | { | |
502 | inet_csk_clear_xmit_timers(sk); | |
503 | } | |
504 | ||
505 | extern unsigned int tcp_sync_mss(struct sock *sk, u32 pmtu); | |
506 | extern unsigned int tcp_current_mss(struct sock *sk); | |
507 | ||
508 | /* Bound MSS / TSO packet size with the half of the window */ | |
509 | static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) | |
510 | { | |
511 | if (tp->max_window && pktsize > (tp->max_window >> 1)) | |
512 | return max(tp->max_window >> 1, 68U - tp->tcp_header_len); | |
513 | else | |
514 | return pktsize; | |
515 | } | |
516 | ||
517 | /* tcp.c */ | |
518 | extern void tcp_get_info(struct sock *, struct tcp_info *); | |
519 | ||
520 | /* Read 'sendfile()'-style from a TCP socket */ | |
521 | typedef int (*sk_read_actor_t)(read_descriptor_t *, struct sk_buff *, | |
522 | unsigned int, size_t); | |
523 | extern int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, | |
524 | sk_read_actor_t recv_actor); | |
525 | ||
526 | extern void tcp_initialize_rcv_mss(struct sock *sk); | |
527 | ||
528 | extern int tcp_mtu_to_mss(struct sock *sk, int pmtu); | |
529 | extern int tcp_mss_to_mtu(struct sock *sk, int mss); | |
530 | extern void tcp_mtup_init(struct sock *sk); | |
531 | ||
532 | static inline void tcp_bound_rto(const struct sock *sk) | |
533 | { | |
534 | if (inet_csk(sk)->icsk_rto > TCP_RTO_MAX) | |
535 | inet_csk(sk)->icsk_rto = TCP_RTO_MAX; | |
536 | } | |
537 | ||
538 | static inline u32 __tcp_set_rto(const struct tcp_sock *tp) | |
539 | { | |
540 | return (tp->srtt >> 3) + tp->rttvar; | |
541 | } | |
542 | ||
543 | static inline void __tcp_fast_path_on(struct tcp_sock *tp, u32 snd_wnd) | |
544 | { | |
545 | tp->pred_flags = htonl((tp->tcp_header_len << 26) | | |
546 | ntohl(TCP_FLAG_ACK) | | |
547 | snd_wnd); | |
548 | } | |
549 | ||
550 | static inline void tcp_fast_path_on(struct tcp_sock *tp) | |
551 | { | |
552 | __tcp_fast_path_on(tp, tp->snd_wnd >> tp->rx_opt.snd_wscale); | |
553 | } | |
554 | ||
555 | static inline void tcp_fast_path_check(struct sock *sk) | |
556 | { | |
557 | struct tcp_sock *tp = tcp_sk(sk); | |
558 | ||
559 | if (skb_queue_empty(&tp->out_of_order_queue) && | |
560 | tp->rcv_wnd && | |
561 | atomic_read(&sk->sk_rmem_alloc) < sk->sk_rcvbuf && | |
562 | !tp->urg_data) | |
563 | tcp_fast_path_on(tp); | |
564 | } | |
565 | ||
566 | /* Compute the actual rto_min value */ | |
567 | static inline u32 tcp_rto_min(struct sock *sk) | |
568 | { | |
569 | struct dst_entry *dst = __sk_dst_get(sk); | |
570 | u32 rto_min = TCP_RTO_MIN; | |
571 | ||
572 | if (dst && dst_metric_locked(dst, RTAX_RTO_MIN)) | |
573 | rto_min = dst_metric_rtt(dst, RTAX_RTO_MIN); | |
574 | return rto_min; | |
575 | } | |
576 | ||
577 | /* Compute the actual receive window we are currently advertising. | |
578 | * Rcv_nxt can be after the window if our peer push more data | |
579 | * than the offered window. | |
580 | */ | |
581 | static inline u32 tcp_receive_window(const struct tcp_sock *tp) | |
582 | { | |
583 | s32 win = tp->rcv_wup + tp->rcv_wnd - tp->rcv_nxt; | |
584 | ||
585 | if (win < 0) | |
586 | win = 0; | |
587 | return (u32) win; | |
588 | } | |
589 | ||
590 | /* Choose a new window, without checks for shrinking, and without | |
591 | * scaling applied to the result. The caller does these things | |
592 | * if necessary. This is a "raw" window selection. | |
593 | */ | |
594 | extern u32 __tcp_select_window(struct sock *sk); | |
595 | ||
596 | /* TCP timestamps are only 32-bits, this causes a slight | |
597 | * complication on 64-bit systems since we store a snapshot | |
598 | * of jiffies in the buffer control blocks below. We decided | |
599 | * to use only the low 32-bits of jiffies and hide the ugly | |
600 | * casts with the following macro. | |
601 | */ | |
602 | #define tcp_time_stamp ((__u32)(jiffies)) | |
603 | ||
604 | /* This is what the send packet queuing engine uses to pass | |
605 | * TCP per-packet control information to the transmission | |
606 | * code. We also store the host-order sequence numbers in | |
607 | * here too. This is 36 bytes on 32-bit architectures, | |
608 | * 40 bytes on 64-bit machines, if this grows please adjust | |
609 | * skbuff.h:skbuff->cb[xxx] size appropriately. | |
610 | */ | |
611 | struct tcp_skb_cb { | |
612 | union { | |
613 | struct inet_skb_parm h4; | |
614 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) | |
615 | struct inet6_skb_parm h6; | |
616 | #endif | |
617 | } header; /* For incoming frames */ | |
618 | __u32 seq; /* Starting sequence number */ | |
619 | __u32 end_seq; /* SEQ + FIN + SYN + datalen */ | |
620 | __u32 when; /* used to compute rtt's */ | |
621 | __u8 flags; /* TCP header flags. */ | |
622 | ||
623 | /* NOTE: These must match up to the flags byte in a | |
624 | * real TCP header. | |
625 | */ | |
626 | #define TCPCB_FLAG_FIN 0x01 | |
627 | #define TCPCB_FLAG_SYN 0x02 | |
628 | #define TCPCB_FLAG_RST 0x04 | |
629 | #define TCPCB_FLAG_PSH 0x08 | |
630 | #define TCPCB_FLAG_ACK 0x10 | |
631 | #define TCPCB_FLAG_URG 0x20 | |
632 | #define TCPCB_FLAG_ECE 0x40 | |
633 | #define TCPCB_FLAG_CWR 0x80 | |
634 | ||
635 | __u8 sacked; /* State flags for SACK/FACK. */ | |
636 | #define TCPCB_SACKED_ACKED 0x01 /* SKB ACK'd by a SACK block */ | |
637 | #define TCPCB_SACKED_RETRANS 0x02 /* SKB retransmitted */ | |
638 | #define TCPCB_LOST 0x04 /* SKB is lost */ | |
639 | #define TCPCB_TAGBITS 0x07 /* All tag bits */ | |
640 | ||
641 | #define TCPCB_EVER_RETRANS 0x80 /* Ever retransmitted frame */ | |
642 | #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS) | |
643 | ||
644 | __u32 ack_seq; /* Sequence number ACK'd */ | |
645 | }; | |
646 | ||
647 | #define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0])) | |
648 | ||
649 | /* Due to TSO, an SKB can be composed of multiple actual | |
650 | * packets. To keep these tracked properly, we use this. | |
651 | */ | |
652 | static inline int tcp_skb_pcount(const struct sk_buff *skb) | |
653 | { | |
654 | return skb_shinfo(skb)->gso_segs; | |
655 | } | |
656 | ||
657 | /* This is valid iff tcp_skb_pcount() > 1. */ | |
658 | static inline int tcp_skb_mss(const struct sk_buff *skb) | |
659 | { | |
660 | return skb_shinfo(skb)->gso_size; | |
661 | } | |
662 | ||
663 | /* Events passed to congestion control interface */ | |
664 | enum tcp_ca_event { | |
665 | CA_EVENT_TX_START, /* first transmit when no packets in flight */ | |
666 | CA_EVENT_CWND_RESTART, /* congestion window restart */ | |
667 | CA_EVENT_COMPLETE_CWR, /* end of congestion recovery */ | |
668 | CA_EVENT_FRTO, /* fast recovery timeout */ | |
669 | CA_EVENT_LOSS, /* loss timeout */ | |
670 | CA_EVENT_FAST_ACK, /* in sequence ack */ | |
671 | CA_EVENT_SLOW_ACK, /* other ack */ | |
672 | }; | |
673 | ||
674 | /* | |
675 | * Interface for adding new TCP congestion control handlers | |
676 | */ | |
677 | #define TCP_CA_NAME_MAX 16 | |
678 | #define TCP_CA_MAX 128 | |
679 | #define TCP_CA_BUF_MAX (TCP_CA_NAME_MAX*TCP_CA_MAX) | |
680 | ||
681 | #define TCP_CONG_NON_RESTRICTED 0x1 | |
682 | #define TCP_CONG_RTT_STAMP 0x2 | |
683 | ||
684 | struct tcp_congestion_ops { | |
685 | struct list_head list; | |
686 | unsigned long flags; | |
687 | ||
688 | /* initialize private data (optional) */ | |
689 | void (*init)(struct sock *sk); | |
690 | /* cleanup private data (optional) */ | |
691 | void (*release)(struct sock *sk); | |
692 | ||
693 | /* return slow start threshold (required) */ | |
694 | u32 (*ssthresh)(struct sock *sk); | |
695 | /* lower bound for congestion window (optional) */ | |
696 | u32 (*min_cwnd)(const struct sock *sk); | |
697 | /* do new cwnd calculation (required) */ | |
698 | void (*cong_avoid)(struct sock *sk, u32 ack, u32 in_flight); | |
699 | /* call before changing ca_state (optional) */ | |
700 | void (*set_state)(struct sock *sk, u8 new_state); | |
701 | /* call when cwnd event occurs (optional) */ | |
702 | void (*cwnd_event)(struct sock *sk, enum tcp_ca_event ev); | |
703 | /* new value of cwnd after loss (optional) */ | |
704 | u32 (*undo_cwnd)(struct sock *sk); | |
705 | /* hook for packet ack accounting (optional) */ | |
706 | void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us); | |
707 | /* get info for inet_diag (optional) */ | |
708 | void (*get_info)(struct sock *sk, u32 ext, struct sk_buff *skb); | |
709 | ||
710 | char name[TCP_CA_NAME_MAX]; | |
711 | struct module *owner; | |
712 | }; | |
713 | ||
714 | extern int tcp_register_congestion_control(struct tcp_congestion_ops *type); | |
715 | extern void tcp_unregister_congestion_control(struct tcp_congestion_ops *type); | |
716 | ||
717 | extern void tcp_init_congestion_control(struct sock *sk); | |
718 | extern void tcp_cleanup_congestion_control(struct sock *sk); | |
719 | extern int tcp_set_default_congestion_control(const char *name); | |
720 | extern void tcp_get_default_congestion_control(char *name); | |
721 | extern void tcp_get_available_congestion_control(char *buf, size_t len); | |
722 | extern void tcp_get_allowed_congestion_control(char *buf, size_t len); | |
723 | extern int tcp_set_allowed_congestion_control(char *allowed); | |
724 | extern int tcp_set_congestion_control(struct sock *sk, const char *name); | |
725 | extern void tcp_slow_start(struct tcp_sock *tp); | |
726 | extern void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w); | |
727 | ||
728 | extern struct tcp_congestion_ops tcp_init_congestion_ops; | |
729 | extern u32 tcp_reno_ssthresh(struct sock *sk); | |
730 | extern void tcp_reno_cong_avoid(struct sock *sk, u32 ack, u32 in_flight); | |
731 | extern u32 tcp_reno_min_cwnd(const struct sock *sk); | |
732 | extern struct tcp_congestion_ops tcp_reno; | |
733 | ||
734 | static inline void tcp_set_ca_state(struct sock *sk, const u8 ca_state) | |
735 | { | |
736 | struct inet_connection_sock *icsk = inet_csk(sk); | |
737 | ||
738 | if (icsk->icsk_ca_ops->set_state) | |
739 | icsk->icsk_ca_ops->set_state(sk, ca_state); | |
740 | icsk->icsk_ca_state = ca_state; | |
741 | } | |
742 | ||
743 | static inline void tcp_ca_event(struct sock *sk, const enum tcp_ca_event event) | |
744 | { | |
745 | const struct inet_connection_sock *icsk = inet_csk(sk); | |
746 | ||
747 | if (icsk->icsk_ca_ops->cwnd_event) | |
748 | icsk->icsk_ca_ops->cwnd_event(sk, event); | |
749 | } | |
750 | ||
751 | /* These functions determine how the current flow behaves in respect of SACK | |
752 | * handling. SACK is negotiated with the peer, and therefore it can vary | |
753 | * between different flows. | |
754 | * | |
755 | * tcp_is_sack - SACK enabled | |
756 | * tcp_is_reno - No SACK | |
757 | * tcp_is_fack - FACK enabled, implies SACK enabled | |
758 | */ | |
759 | static inline int tcp_is_sack(const struct tcp_sock *tp) | |
760 | { | |
761 | return tp->rx_opt.sack_ok; | |
762 | } | |
763 | ||
764 | static inline int tcp_is_reno(const struct tcp_sock *tp) | |
765 | { | |
766 | return !tcp_is_sack(tp); | |
767 | } | |
768 | ||
769 | static inline int tcp_is_fack(const struct tcp_sock *tp) | |
770 | { | |
771 | return tp->rx_opt.sack_ok & 2; | |
772 | } | |
773 | ||
774 | static inline void tcp_enable_fack(struct tcp_sock *tp) | |
775 | { | |
776 | tp->rx_opt.sack_ok |= 2; | |
777 | } | |
778 | ||
779 | static inline unsigned int tcp_left_out(const struct tcp_sock *tp) | |
780 | { | |
781 | return tp->sacked_out + tp->lost_out; | |
782 | } | |
783 | ||
784 | /* This determines how many packets are "in the network" to the best | |
785 | * of our knowledge. In many cases it is conservative, but where | |
786 | * detailed information is available from the receiver (via SACK | |
787 | * blocks etc.) we can make more aggressive calculations. | |
788 | * | |
789 | * Use this for decisions involving congestion control, use just | |
790 | * tp->packets_out to determine if the send queue is empty or not. | |
791 | * | |
792 | * Read this equation as: | |
793 | * | |
794 | * "Packets sent once on transmission queue" MINUS | |
795 | * "Packets left network, but not honestly ACKed yet" PLUS | |
796 | * "Packets fast retransmitted" | |
797 | */ | |
798 | static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp) | |
799 | { | |
800 | return tp->packets_out - tcp_left_out(tp) + tp->retrans_out; | |
801 | } | |
802 | ||
803 | #define TCP_INFINITE_SSTHRESH 0x7fffffff | |
804 | ||
805 | static inline bool tcp_in_initial_slowstart(const struct tcp_sock *tp) | |
806 | { | |
807 | return tp->snd_ssthresh >= TCP_INFINITE_SSTHRESH; | |
808 | } | |
809 | ||
810 | /* If cwnd > ssthresh, we may raise ssthresh to be half-way to cwnd. | |
811 | * The exception is rate halving phase, when cwnd is decreasing towards | |
812 | * ssthresh. | |
813 | */ | |
814 | static inline __u32 tcp_current_ssthresh(const struct sock *sk) | |
815 | { | |
816 | const struct tcp_sock *tp = tcp_sk(sk); | |
817 | if ((1 << inet_csk(sk)->icsk_ca_state) & (TCPF_CA_CWR | TCPF_CA_Recovery)) | |
818 | return tp->snd_ssthresh; | |
819 | else | |
820 | return max(tp->snd_ssthresh, | |
821 | ((tp->snd_cwnd >> 1) + | |
822 | (tp->snd_cwnd >> 2))); | |
823 | } | |
824 | ||
825 | /* Use define here intentionally to get WARN_ON location shown at the caller */ | |
826 | #define tcp_verify_left_out(tp) WARN_ON(tcp_left_out(tp) > tp->packets_out) | |
827 | ||
828 | extern void tcp_enter_cwr(struct sock *sk, const int set_ssthresh); | |
829 | extern __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst); | |
830 | ||
831 | /* Slow start with delack produces 3 packets of burst, so that | |
832 | * it is safe "de facto". This will be the default - same as | |
833 | * the default reordering threshold - but if reordering increases, | |
834 | * we must be able to allow cwnd to burst at least this much in order | |
835 | * to not pull it back when holes are filled. | |
836 | */ | |
837 | static __inline__ __u32 tcp_max_burst(const struct tcp_sock *tp) | |
838 | { | |
839 | return tp->reordering; | |
840 | } | |
841 | ||
842 | /* Returns end sequence number of the receiver's advertised window */ | |
843 | static inline u32 tcp_wnd_end(const struct tcp_sock *tp) | |
844 | { | |
845 | return tp->snd_una + tp->snd_wnd; | |
846 | } | |
847 | extern int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight); | |
848 | ||
849 | static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss, | |
850 | const struct sk_buff *skb) | |
851 | { | |
852 | if (skb->len < mss) | |
853 | tp->snd_sml = TCP_SKB_CB(skb)->end_seq; | |
854 | } | |
855 | ||
856 | static inline void tcp_check_probe_timer(struct sock *sk) | |
857 | { | |
858 | struct tcp_sock *tp = tcp_sk(sk); | |
859 | const struct inet_connection_sock *icsk = inet_csk(sk); | |
860 | ||
861 | if (!tp->packets_out && !icsk->icsk_pending) | |
862 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_PROBE0, | |
863 | icsk->icsk_rto, TCP_RTO_MAX); | |
864 | } | |
865 | ||
866 | static inline void tcp_init_wl(struct tcp_sock *tp, u32 seq) | |
867 | { | |
868 | tp->snd_wl1 = seq; | |
869 | } | |
870 | ||
871 | static inline void tcp_update_wl(struct tcp_sock *tp, u32 seq) | |
872 | { | |
873 | tp->snd_wl1 = seq; | |
874 | } | |
875 | ||
876 | /* | |
877 | * Calculate(/check) TCP checksum | |
878 | */ | |
879 | static inline __sum16 tcp_v4_check(int len, __be32 saddr, | |
880 | __be32 daddr, __wsum base) | |
881 | { | |
882 | return csum_tcpudp_magic(saddr,daddr,len,IPPROTO_TCP,base); | |
883 | } | |
884 | ||
885 | static inline __sum16 __tcp_checksum_complete(struct sk_buff *skb) | |
886 | { | |
887 | return __skb_checksum_complete(skb); | |
888 | } | |
889 | ||
890 | static inline int tcp_checksum_complete(struct sk_buff *skb) | |
891 | { | |
892 | return !skb_csum_unnecessary(skb) && | |
893 | __tcp_checksum_complete(skb); | |
894 | } | |
895 | ||
896 | /* Prequeue for VJ style copy to user, combined with checksumming. */ | |
897 | ||
898 | static inline void tcp_prequeue_init(struct tcp_sock *tp) | |
899 | { | |
900 | tp->ucopy.task = NULL; | |
901 | tp->ucopy.len = 0; | |
902 | tp->ucopy.memory = 0; | |
903 | skb_queue_head_init(&tp->ucopy.prequeue); | |
904 | #ifdef CONFIG_NET_DMA | |
905 | tp->ucopy.dma_chan = NULL; | |
906 | tp->ucopy.wakeup = 0; | |
907 | tp->ucopy.pinned_list = NULL; | |
908 | tp->ucopy.dma_cookie = 0; | |
909 | #endif | |
910 | } | |
911 | ||
912 | /* Packet is added to VJ-style prequeue for processing in process | |
913 | * context, if a reader task is waiting. Apparently, this exciting | |
914 | * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93) | |
915 | * failed somewhere. Latency? Burstiness? Well, at least now we will | |
916 | * see, why it failed. 8)8) --ANK | |
917 | * | |
918 | * NOTE: is this not too big to inline? | |
919 | */ | |
920 | static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb) | |
921 | { | |
922 | struct tcp_sock *tp = tcp_sk(sk); | |
923 | ||
924 | if (sysctl_tcp_low_latency || !tp->ucopy.task) | |
925 | return 0; | |
926 | ||
927 | __skb_queue_tail(&tp->ucopy.prequeue, skb); | |
928 | tp->ucopy.memory += skb->truesize; | |
929 | if (tp->ucopy.memory > sk->sk_rcvbuf) { | |
930 | struct sk_buff *skb1; | |
931 | ||
932 | BUG_ON(sock_owned_by_user(sk)); | |
933 | ||
934 | while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) { | |
935 | sk_backlog_rcv(sk, skb1); | |
936 | NET_INC_STATS_BH(sock_net(sk), | |
937 | LINUX_MIB_TCPPREQUEUEDROPPED); | |
938 | } | |
939 | ||
940 | tp->ucopy.memory = 0; | |
941 | } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) { | |
942 | wake_up_interruptible_sync_poll(sk->sk_sleep, | |
943 | POLLIN | POLLRDNORM | POLLRDBAND); | |
944 | if (!inet_csk_ack_scheduled(sk)) | |
945 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, | |
946 | (3 * tcp_rto_min(sk)) / 4, | |
947 | TCP_RTO_MAX); | |
948 | } | |
949 | return 1; | |
950 | } | |
951 | ||
952 | ||
953 | #undef STATE_TRACE | |
954 | ||
955 | #ifdef STATE_TRACE | |
956 | static const char *statename[]={ | |
957 | "Unused","Established","Syn Sent","Syn Recv", | |
958 | "Fin Wait 1","Fin Wait 2","Time Wait", "Close", | |
959 | "Close Wait","Last ACK","Listen","Closing" | |
960 | }; | |
961 | #endif | |
962 | extern void tcp_set_state(struct sock *sk, int state); | |
963 | ||
964 | extern void tcp_done(struct sock *sk); | |
965 | ||
966 | static inline void tcp_sack_reset(struct tcp_options_received *rx_opt) | |
967 | { | |
968 | rx_opt->dsack = 0; | |
969 | rx_opt->num_sacks = 0; | |
970 | } | |
971 | ||
972 | /* Determine a window scaling and initial window to offer. */ | |
973 | extern void tcp_select_initial_window(int __space, __u32 mss, | |
974 | __u32 *rcv_wnd, __u32 *window_clamp, | |
975 | int wscale_ok, __u8 *rcv_wscale, | |
976 | __u32 init_rcv_wnd); | |
977 | ||
978 | static inline int tcp_win_from_space(int space) | |
979 | { | |
980 | return sysctl_tcp_adv_win_scale<=0 ? | |
981 | (space>>(-sysctl_tcp_adv_win_scale)) : | |
982 | space - (space>>sysctl_tcp_adv_win_scale); | |
983 | } | |
984 | ||
985 | /* Note: caller must be prepared to deal with negative returns */ | |
986 | static inline int tcp_space(const struct sock *sk) | |
987 | { | |
988 | return tcp_win_from_space(sk->sk_rcvbuf - | |
989 | atomic_read(&sk->sk_rmem_alloc)); | |
990 | } | |
991 | ||
992 | static inline int tcp_full_space(const struct sock *sk) | |
993 | { | |
994 | return tcp_win_from_space(sk->sk_rcvbuf); | |
995 | } | |
996 | ||
997 | static inline void tcp_openreq_init(struct request_sock *req, | |
998 | struct tcp_options_received *rx_opt, | |
999 | struct sk_buff *skb) | |
1000 | { | |
1001 | struct inet_request_sock *ireq = inet_rsk(req); | |
1002 | ||
1003 | req->rcv_wnd = 0; /* So that tcp_send_synack() knows! */ | |
1004 | req->cookie_ts = 0; | |
1005 | tcp_rsk(req)->rcv_isn = TCP_SKB_CB(skb)->seq; | |
1006 | req->mss = rx_opt->mss_clamp; | |
1007 | req->ts_recent = rx_opt->saw_tstamp ? rx_opt->rcv_tsval : 0; | |
1008 | ireq->tstamp_ok = rx_opt->tstamp_ok; | |
1009 | ireq->sack_ok = rx_opt->sack_ok; | |
1010 | ireq->snd_wscale = rx_opt->snd_wscale; | |
1011 | ireq->wscale_ok = rx_opt->wscale_ok; | |
1012 | ireq->acked = 0; | |
1013 | ireq->ecn_ok = 0; | |
1014 | ireq->rmt_port = tcp_hdr(skb)->source; | |
1015 | ireq->loc_port = tcp_hdr(skb)->dest; | |
1016 | } | |
1017 | ||
1018 | extern void tcp_enter_memory_pressure(struct sock *sk); | |
1019 | ||
1020 | static inline int keepalive_intvl_when(const struct tcp_sock *tp) | |
1021 | { | |
1022 | return tp->keepalive_intvl ? : sysctl_tcp_keepalive_intvl; | |
1023 | } | |
1024 | ||
1025 | static inline int keepalive_time_when(const struct tcp_sock *tp) | |
1026 | { | |
1027 | return tp->keepalive_time ? : sysctl_tcp_keepalive_time; | |
1028 | } | |
1029 | ||
1030 | static inline int keepalive_probes(const struct tcp_sock *tp) | |
1031 | { | |
1032 | return tp->keepalive_probes ? : sysctl_tcp_keepalive_probes; | |
1033 | } | |
1034 | ||
1035 | static inline int tcp_fin_time(const struct sock *sk) | |
1036 | { | |
1037 | int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout; | |
1038 | const int rto = inet_csk(sk)->icsk_rto; | |
1039 | ||
1040 | if (fin_timeout < (rto << 2) - (rto >> 1)) | |
1041 | fin_timeout = (rto << 2) - (rto >> 1); | |
1042 | ||
1043 | return fin_timeout; | |
1044 | } | |
1045 | ||
1046 | static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, | |
1047 | int paws_win) | |
1048 | { | |
1049 | if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) | |
1050 | return 1; | |
1051 | if (unlikely(get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)) | |
1052 | return 1; | |
1053 | ||
1054 | return 0; | |
1055 | } | |
1056 | ||
1057 | static inline int tcp_paws_reject(const struct tcp_options_received *rx_opt, | |
1058 | int rst) | |
1059 | { | |
1060 | if (tcp_paws_check(rx_opt, 0)) | |
1061 | return 0; | |
1062 | ||
1063 | /* RST segments are not recommended to carry timestamp, | |
1064 | and, if they do, it is recommended to ignore PAWS because | |
1065 | "their cleanup function should take precedence over timestamps." | |
1066 | Certainly, it is mistake. It is necessary to understand the reasons | |
1067 | of this constraint to relax it: if peer reboots, clock may go | |
1068 | out-of-sync and half-open connections will not be reset. | |
1069 | Actually, the problem would be not existing if all | |
1070 | the implementations followed draft about maintaining clock | |
1071 | via reboots. Linux-2.2 DOES NOT! | |
1072 | ||
1073 | However, we can relax time bounds for RST segments to MSL. | |
1074 | */ | |
1075 | if (rst && get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_MSL) | |
1076 | return 0; | |
1077 | return 1; | |
1078 | } | |
1079 | ||
1080 | #define TCP_CHECK_TIMER(sk) do { } while (0) | |
1081 | ||
1082 | static inline void tcp_mib_init(struct net *net) | |
1083 | { | |
1084 | /* See RFC 2012 */ | |
1085 | TCP_ADD_STATS_USER(net, TCP_MIB_RTOALGORITHM, 1); | |
1086 | TCP_ADD_STATS_USER(net, TCP_MIB_RTOMIN, TCP_RTO_MIN*1000/HZ); | |
1087 | TCP_ADD_STATS_USER(net, TCP_MIB_RTOMAX, TCP_RTO_MAX*1000/HZ); | |
1088 | TCP_ADD_STATS_USER(net, TCP_MIB_MAXCONN, -1); | |
1089 | } | |
1090 | ||
1091 | /* from STCP */ | |
1092 | static inline void tcp_clear_retrans_hints_partial(struct tcp_sock *tp) | |
1093 | { | |
1094 | tp->lost_skb_hint = NULL; | |
1095 | tp->scoreboard_skb_hint = NULL; | |
1096 | } | |
1097 | ||
1098 | static inline void tcp_clear_all_retrans_hints(struct tcp_sock *tp) | |
1099 | { | |
1100 | tcp_clear_retrans_hints_partial(tp); | |
1101 | tp->retransmit_skb_hint = NULL; | |
1102 | } | |
1103 | ||
1104 | /* MD5 Signature */ | |
1105 | struct crypto_hash; | |
1106 | ||
1107 | /* - key database */ | |
1108 | struct tcp_md5sig_key { | |
1109 | u8 *key; | |
1110 | u8 keylen; | |
1111 | }; | |
1112 | ||
1113 | struct tcp4_md5sig_key { | |
1114 | struct tcp_md5sig_key base; | |
1115 | __be32 addr; | |
1116 | }; | |
1117 | ||
1118 | struct tcp6_md5sig_key { | |
1119 | struct tcp_md5sig_key base; | |
1120 | #if 0 | |
1121 | u32 scope_id; /* XXX */ | |
1122 | #endif | |
1123 | struct in6_addr addr; | |
1124 | }; | |
1125 | ||
1126 | /* - sock block */ | |
1127 | struct tcp_md5sig_info { | |
1128 | struct tcp4_md5sig_key *keys4; | |
1129 | #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) | |
1130 | struct tcp6_md5sig_key *keys6; | |
1131 | u32 entries6; | |
1132 | u32 alloced6; | |
1133 | #endif | |
1134 | u32 entries4; | |
1135 | u32 alloced4; | |
1136 | }; | |
1137 | ||
1138 | /* - pseudo header */ | |
1139 | struct tcp4_pseudohdr { | |
1140 | __be32 saddr; | |
1141 | __be32 daddr; | |
1142 | __u8 pad; | |
1143 | __u8 protocol; | |
1144 | __be16 len; | |
1145 | }; | |
1146 | ||
1147 | struct tcp6_pseudohdr { | |
1148 | struct in6_addr saddr; | |
1149 | struct in6_addr daddr; | |
1150 | __be32 len; | |
1151 | __be32 protocol; /* including padding */ | |
1152 | }; | |
1153 | ||
1154 | union tcp_md5sum_block { | |
1155 | struct tcp4_pseudohdr ip4; | |
1156 | #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) | |
1157 | struct tcp6_pseudohdr ip6; | |
1158 | #endif | |
1159 | }; | |
1160 | ||
1161 | /* - pool: digest algorithm, hash description and scratch buffer */ | |
1162 | struct tcp_md5sig_pool { | |
1163 | struct hash_desc md5_desc; | |
1164 | union tcp_md5sum_block md5_blk; | |
1165 | }; | |
1166 | ||
1167 | #define TCP_MD5SIG_MAXKEYS (~(u32)0) /* really?! */ | |
1168 | ||
1169 | /* - functions */ | |
1170 | extern int tcp_v4_md5_hash_skb(char *md5_hash, | |
1171 | struct tcp_md5sig_key *key, | |
1172 | struct sock *sk, | |
1173 | struct request_sock *req, | |
1174 | struct sk_buff *skb); | |
1175 | ||
1176 | extern struct tcp_md5sig_key *tcp_v4_md5_lookup(struct sock *sk, | |
1177 | struct sock *addr_sk); | |
1178 | ||
1179 | extern int tcp_v4_md5_do_add(struct sock *sk, | |
1180 | __be32 addr, | |
1181 | u8 *newkey, | |
1182 | u8 newkeylen); | |
1183 | ||
1184 | extern int tcp_v4_md5_do_del(struct sock *sk, | |
1185 | __be32 addr); | |
1186 | ||
1187 | #ifdef CONFIG_TCP_MD5SIG | |
1188 | #define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_keylen ? \ | |
1189 | &(struct tcp_md5sig_key) { \ | |
1190 | .key = (twsk)->tw_md5_key, \ | |
1191 | .keylen = (twsk)->tw_md5_keylen, \ | |
1192 | } : NULL) | |
1193 | #else | |
1194 | #define tcp_twsk_md5_key(twsk) NULL | |
1195 | #endif | |
1196 | ||
1197 | extern struct tcp_md5sig_pool * __percpu *tcp_alloc_md5sig_pool(struct sock *); | |
1198 | extern void tcp_free_md5sig_pool(void); | |
1199 | ||
1200 | extern struct tcp_md5sig_pool *__tcp_get_md5sig_pool(int cpu); | |
1201 | extern void __tcp_put_md5sig_pool(void); | |
1202 | extern int tcp_md5_hash_header(struct tcp_md5sig_pool *, struct tcphdr *); | |
1203 | extern int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *, struct sk_buff *, | |
1204 | unsigned header_len); | |
1205 | extern int tcp_md5_hash_key(struct tcp_md5sig_pool *hp, | |
1206 | struct tcp_md5sig_key *key); | |
1207 | ||
1208 | static inline | |
1209 | struct tcp_md5sig_pool *tcp_get_md5sig_pool(void) | |
1210 | { | |
1211 | int cpu = get_cpu(); | |
1212 | struct tcp_md5sig_pool *ret = __tcp_get_md5sig_pool(cpu); | |
1213 | if (!ret) | |
1214 | put_cpu(); | |
1215 | return ret; | |
1216 | } | |
1217 | ||
1218 | static inline void tcp_put_md5sig_pool(void) | |
1219 | { | |
1220 | __tcp_put_md5sig_pool(); | |
1221 | put_cpu(); | |
1222 | } | |
1223 | ||
1224 | /* write queue abstraction */ | |
1225 | static inline void tcp_write_queue_purge(struct sock *sk) | |
1226 | { | |
1227 | struct sk_buff *skb; | |
1228 | ||
1229 | while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) | |
1230 | sk_wmem_free_skb(sk, skb); | |
1231 | sk_mem_reclaim(sk); | |
1232 | tcp_clear_all_retrans_hints(tcp_sk(sk)); | |
1233 | } | |
1234 | ||
1235 | static inline struct sk_buff *tcp_write_queue_head(struct sock *sk) | |
1236 | { | |
1237 | return skb_peek(&sk->sk_write_queue); | |
1238 | } | |
1239 | ||
1240 | static inline struct sk_buff *tcp_write_queue_tail(struct sock *sk) | |
1241 | { | |
1242 | return skb_peek_tail(&sk->sk_write_queue); | |
1243 | } | |
1244 | ||
1245 | static inline struct sk_buff *tcp_write_queue_next(struct sock *sk, struct sk_buff *skb) | |
1246 | { | |
1247 | return skb_queue_next(&sk->sk_write_queue, skb); | |
1248 | } | |
1249 | ||
1250 | static inline struct sk_buff *tcp_write_queue_prev(struct sock *sk, struct sk_buff *skb) | |
1251 | { | |
1252 | return skb_queue_prev(&sk->sk_write_queue, skb); | |
1253 | } | |
1254 | ||
1255 | #define tcp_for_write_queue(skb, sk) \ | |
1256 | skb_queue_walk(&(sk)->sk_write_queue, skb) | |
1257 | ||
1258 | #define tcp_for_write_queue_from(skb, sk) \ | |
1259 | skb_queue_walk_from(&(sk)->sk_write_queue, skb) | |
1260 | ||
1261 | #define tcp_for_write_queue_from_safe(skb, tmp, sk) \ | |
1262 | skb_queue_walk_from_safe(&(sk)->sk_write_queue, skb, tmp) | |
1263 | ||
1264 | static inline struct sk_buff *tcp_send_head(struct sock *sk) | |
1265 | { | |
1266 | return sk->sk_send_head; | |
1267 | } | |
1268 | ||
1269 | static inline bool tcp_skb_is_last(const struct sock *sk, | |
1270 | const struct sk_buff *skb) | |
1271 | { | |
1272 | return skb_queue_is_last(&sk->sk_write_queue, skb); | |
1273 | } | |
1274 | ||
1275 | static inline void tcp_advance_send_head(struct sock *sk, struct sk_buff *skb) | |
1276 | { | |
1277 | if (tcp_skb_is_last(sk, skb)) | |
1278 | sk->sk_send_head = NULL; | |
1279 | else | |
1280 | sk->sk_send_head = tcp_write_queue_next(sk, skb); | |
1281 | } | |
1282 | ||
1283 | static inline void tcp_check_send_head(struct sock *sk, struct sk_buff *skb_unlinked) | |
1284 | { | |
1285 | if (sk->sk_send_head == skb_unlinked) | |
1286 | sk->sk_send_head = NULL; | |
1287 | } | |
1288 | ||
1289 | static inline void tcp_init_send_head(struct sock *sk) | |
1290 | { | |
1291 | sk->sk_send_head = NULL; | |
1292 | } | |
1293 | ||
1294 | static inline void __tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) | |
1295 | { | |
1296 | __skb_queue_tail(&sk->sk_write_queue, skb); | |
1297 | } | |
1298 | ||
1299 | static inline void tcp_add_write_queue_tail(struct sock *sk, struct sk_buff *skb) | |
1300 | { | |
1301 | __tcp_add_write_queue_tail(sk, skb); | |
1302 | ||
1303 | /* Queue it, remembering where we must start sending. */ | |
1304 | if (sk->sk_send_head == NULL) { | |
1305 | sk->sk_send_head = skb; | |
1306 | ||
1307 | if (tcp_sk(sk)->highest_sack == NULL) | |
1308 | tcp_sk(sk)->highest_sack = skb; | |
1309 | } | |
1310 | } | |
1311 | ||
1312 | static inline void __tcp_add_write_queue_head(struct sock *sk, struct sk_buff *skb) | |
1313 | { | |
1314 | __skb_queue_head(&sk->sk_write_queue, skb); | |
1315 | } | |
1316 | ||
1317 | /* Insert buff after skb on the write queue of sk. */ | |
1318 | static inline void tcp_insert_write_queue_after(struct sk_buff *skb, | |
1319 | struct sk_buff *buff, | |
1320 | struct sock *sk) | |
1321 | { | |
1322 | __skb_queue_after(&sk->sk_write_queue, skb, buff); | |
1323 | } | |
1324 | ||
1325 | /* Insert new before skb on the write queue of sk. */ | |
1326 | static inline void tcp_insert_write_queue_before(struct sk_buff *new, | |
1327 | struct sk_buff *skb, | |
1328 | struct sock *sk) | |
1329 | { | |
1330 | __skb_queue_before(&sk->sk_write_queue, skb, new); | |
1331 | ||
1332 | if (sk->sk_send_head == skb) | |
1333 | sk->sk_send_head = new; | |
1334 | } | |
1335 | ||
1336 | static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) | |
1337 | { | |
1338 | __skb_unlink(skb, &sk->sk_write_queue); | |
1339 | } | |
1340 | ||
1341 | static inline int tcp_write_queue_empty(struct sock *sk) | |
1342 | { | |
1343 | return skb_queue_empty(&sk->sk_write_queue); | |
1344 | } | |
1345 | ||
1346 | static inline void tcp_push_pending_frames(struct sock *sk) | |
1347 | { | |
1348 | if (tcp_send_head(sk)) { | |
1349 | struct tcp_sock *tp = tcp_sk(sk); | |
1350 | ||
1351 | __tcp_push_pending_frames(sk, tcp_current_mss(sk), tp->nonagle); | |
1352 | } | |
1353 | } | |
1354 | ||
1355 | /* Start sequence of the highest skb with SACKed bit, valid only if | |
1356 | * sacked > 0 or when the caller has ensured validity by itself. | |
1357 | */ | |
1358 | static inline u32 tcp_highest_sack_seq(struct tcp_sock *tp) | |
1359 | { | |
1360 | if (!tp->sacked_out) | |
1361 | return tp->snd_una; | |
1362 | ||
1363 | if (tp->highest_sack == NULL) | |
1364 | return tp->snd_nxt; | |
1365 | ||
1366 | return TCP_SKB_CB(tp->highest_sack)->seq; | |
1367 | } | |
1368 | ||
1369 | static inline void tcp_advance_highest_sack(struct sock *sk, struct sk_buff *skb) | |
1370 | { | |
1371 | tcp_sk(sk)->highest_sack = tcp_skb_is_last(sk, skb) ? NULL : | |
1372 | tcp_write_queue_next(sk, skb); | |
1373 | } | |
1374 | ||
1375 | static inline struct sk_buff *tcp_highest_sack(struct sock *sk) | |
1376 | { | |
1377 | return tcp_sk(sk)->highest_sack; | |
1378 | } | |
1379 | ||
1380 | static inline void tcp_highest_sack_reset(struct sock *sk) | |
1381 | { | |
1382 | tcp_sk(sk)->highest_sack = tcp_write_queue_head(sk); | |
1383 | } | |
1384 | ||
1385 | /* Called when old skb is about to be deleted (to be combined with new skb) */ | |
1386 | static inline void tcp_highest_sack_combine(struct sock *sk, | |
1387 | struct sk_buff *old, | |
1388 | struct sk_buff *new) | |
1389 | { | |
1390 | if (tcp_sk(sk)->sacked_out && (old == tcp_sk(sk)->highest_sack)) | |
1391 | tcp_sk(sk)->highest_sack = new; | |
1392 | } | |
1393 | ||
1394 | /* Determines whether this is a thin stream (which may suffer from | |
1395 | * increased latency). Used to trigger latency-reducing mechanisms. | |
1396 | */ | |
1397 | static inline unsigned int tcp_stream_is_thin(struct tcp_sock *tp) | |
1398 | { | |
1399 | return tp->packets_out < 4 && !tcp_in_initial_slowstart(tp); | |
1400 | } | |
1401 | ||
1402 | /* /proc */ | |
1403 | enum tcp_seq_states { | |
1404 | TCP_SEQ_STATE_LISTENING, | |
1405 | TCP_SEQ_STATE_OPENREQ, | |
1406 | TCP_SEQ_STATE_ESTABLISHED, | |
1407 | TCP_SEQ_STATE_TIME_WAIT, | |
1408 | }; | |
1409 | ||
1410 | struct tcp_seq_afinfo { | |
1411 | char *name; | |
1412 | sa_family_t family; | |
1413 | struct file_operations seq_fops; | |
1414 | struct seq_operations seq_ops; | |
1415 | }; | |
1416 | ||
1417 | struct tcp_iter_state { | |
1418 | struct seq_net_private p; | |
1419 | sa_family_t family; | |
1420 | enum tcp_seq_states state; | |
1421 | struct sock *syn_wait_sk; | |
1422 | int bucket, sbucket, num, uid; | |
1423 | }; | |
1424 | ||
1425 | extern int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo); | |
1426 | extern void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo); | |
1427 | ||
1428 | extern struct request_sock_ops tcp_request_sock_ops; | |
1429 | extern struct request_sock_ops tcp6_request_sock_ops; | |
1430 | ||
1431 | extern void tcp_v4_destroy_sock(struct sock *sk); | |
1432 | ||
1433 | extern int tcp_v4_gso_send_check(struct sk_buff *skb); | |
1434 | extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features); | |
1435 | extern struct sk_buff **tcp_gro_receive(struct sk_buff **head, | |
1436 | struct sk_buff *skb); | |
1437 | extern struct sk_buff **tcp4_gro_receive(struct sk_buff **head, | |
1438 | struct sk_buff *skb); | |
1439 | extern int tcp_gro_complete(struct sk_buff *skb); | |
1440 | extern int tcp4_gro_complete(struct sk_buff *skb); | |
1441 | ||
1442 | #ifdef CONFIG_PROC_FS | |
1443 | extern int tcp4_proc_init(void); | |
1444 | extern void tcp4_proc_exit(void); | |
1445 | #endif | |
1446 | ||
1447 | /* TCP af-specific functions */ | |
1448 | struct tcp_sock_af_ops { | |
1449 | #ifdef CONFIG_TCP_MD5SIG | |
1450 | struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk, | |
1451 | struct sock *addr_sk); | |
1452 | int (*calc_md5_hash) (char *location, | |
1453 | struct tcp_md5sig_key *md5, | |
1454 | struct sock *sk, | |
1455 | struct request_sock *req, | |
1456 | struct sk_buff *skb); | |
1457 | int (*md5_add) (struct sock *sk, | |
1458 | struct sock *addr_sk, | |
1459 | u8 *newkey, | |
1460 | u8 len); | |
1461 | int (*md5_parse) (struct sock *sk, | |
1462 | char __user *optval, | |
1463 | int optlen); | |
1464 | #endif | |
1465 | }; | |
1466 | ||
1467 | struct tcp_request_sock_ops { | |
1468 | #ifdef CONFIG_TCP_MD5SIG | |
1469 | struct tcp_md5sig_key *(*md5_lookup) (struct sock *sk, | |
1470 | struct request_sock *req); | |
1471 | int (*calc_md5_hash) (char *location, | |
1472 | struct tcp_md5sig_key *md5, | |
1473 | struct sock *sk, | |
1474 | struct request_sock *req, | |
1475 | struct sk_buff *skb); | |
1476 | #endif | |
1477 | }; | |
1478 | ||
1479 | /* Using SHA1 for now, define some constants. | |
1480 | */ | |
1481 | #define COOKIE_DIGEST_WORDS (SHA_DIGEST_WORDS) | |
1482 | #define COOKIE_MESSAGE_WORDS (SHA_MESSAGE_BYTES / 4) | |
1483 | #define COOKIE_WORKSPACE_WORDS (COOKIE_DIGEST_WORDS + COOKIE_MESSAGE_WORDS) | |
1484 | ||
1485 | extern int tcp_cookie_generator(u32 *bakery); | |
1486 | ||
1487 | /** | |
1488 | * struct tcp_cookie_values - each socket needs extra space for the | |
1489 | * cookies, together with (optional) space for any SYN data. | |
1490 | * | |
1491 | * A tcp_sock contains a pointer to the current value, and this is | |
1492 | * cloned to the tcp_timewait_sock. | |
1493 | * | |
1494 | * @cookie_pair: variable data from the option exchange. | |
1495 | * | |
1496 | * @cookie_desired: user specified tcpct_cookie_desired. Zero | |
1497 | * indicates default (sysctl_tcp_cookie_size). | |
1498 | * After cookie sent, remembers size of cookie. | |
1499 | * Range 0, TCP_COOKIE_MIN to TCP_COOKIE_MAX. | |
1500 | * | |
1501 | * @s_data_desired: user specified tcpct_s_data_desired. When the | |
1502 | * constant payload is specified (@s_data_constant), | |
1503 | * holds its length instead. | |
1504 | * Range 0 to TCP_MSS_DESIRED. | |
1505 | * | |
1506 | * @s_data_payload: constant data that is to be included in the | |
1507 | * payload of SYN or SYNACK segments when the | |
1508 | * cookie option is present. | |
1509 | */ | |
1510 | struct tcp_cookie_values { | |
1511 | struct kref kref; | |
1512 | u8 cookie_pair[TCP_COOKIE_PAIR_SIZE]; | |
1513 | u8 cookie_pair_size; | |
1514 | u8 cookie_desired; | |
1515 | u16 s_data_desired:11, | |
1516 | s_data_constant:1, | |
1517 | s_data_in:1, | |
1518 | s_data_out:1, | |
1519 | s_data_unused:2; | |
1520 | u8 s_data_payload[0]; | |
1521 | }; | |
1522 | ||
1523 | static inline void tcp_cookie_values_release(struct kref *kref) | |
1524 | { | |
1525 | kfree(container_of(kref, struct tcp_cookie_values, kref)); | |
1526 | } | |
1527 | ||
1528 | /* The length of constant payload data. Note that s_data_desired is | |
1529 | * overloaded, depending on s_data_constant: either the length of constant | |
1530 | * data (returned here) or the limit on variable data. | |
1531 | */ | |
1532 | static inline int tcp_s_data_size(const struct tcp_sock *tp) | |
1533 | { | |
1534 | return (tp->cookie_values != NULL && tp->cookie_values->s_data_constant) | |
1535 | ? tp->cookie_values->s_data_desired | |
1536 | : 0; | |
1537 | } | |
1538 | ||
1539 | /** | |
1540 | * struct tcp_extend_values - tcp_ipv?.c to tcp_output.c workspace. | |
1541 | * | |
1542 | * As tcp_request_sock has already been extended in other places, the | |
1543 | * only remaining method is to pass stack values along as function | |
1544 | * parameters. These parameters are not needed after sending SYNACK. | |
1545 | * | |
1546 | * @cookie_bakery: cryptographic secret and message workspace. | |
1547 | * | |
1548 | * @cookie_plus: bytes in authenticator/cookie option, copied from | |
1549 | * struct tcp_options_received (above). | |
1550 | */ | |
1551 | struct tcp_extend_values { | |
1552 | struct request_values rv; | |
1553 | u32 cookie_bakery[COOKIE_WORKSPACE_WORDS]; | |
1554 | u8 cookie_plus:6, | |
1555 | cookie_out_never:1, | |
1556 | cookie_in_always:1; | |
1557 | }; | |
1558 | ||
1559 | static inline struct tcp_extend_values *tcp_xv(struct request_values *rvp) | |
1560 | { | |
1561 | return (struct tcp_extend_values *)rvp; | |
1562 | } | |
1563 | ||
1564 | extern void tcp_v4_init(void); | |
1565 | extern void tcp_init(void); | |
1566 | ||
1567 | #endif /* _TCP_H */ |