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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 protocol. | |
7 | * | |
8 | * Version: @(#)tcp.h 1.0.2 04/28/93 | |
9 | * | |
10 | * Author: Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or | |
13 | * modify it under the terms of the GNU General Public License | |
14 | * as published by the Free Software Foundation; either version | |
15 | * 2 of the License, or (at your option) any later version. | |
16 | */ | |
17 | #ifndef _LINUX_TCP_H | |
18 | #define _LINUX_TCP_H | |
19 | ||
20 | ||
21 | #include <linux/skbuff.h> | |
22 | #include <linux/dmaengine.h> | |
23 | #include <net/sock.h> | |
24 | #include <net/inet_connection_sock.h> | |
25 | #include <net/inet_timewait_sock.h> | |
26 | #include <uapi/linux/tcp.h> | |
27 | ||
28 | static inline struct tcphdr *tcp_hdr(const struct sk_buff *skb) | |
29 | { | |
30 | return (struct tcphdr *)skb_transport_header(skb); | |
31 | } | |
32 | ||
33 | static inline unsigned int tcp_hdrlen(const struct sk_buff *skb) | |
34 | { | |
35 | return tcp_hdr(skb)->doff * 4; | |
36 | } | |
37 | ||
38 | static inline struct tcphdr *inner_tcp_hdr(const struct sk_buff *skb) | |
39 | { | |
40 | return (struct tcphdr *)skb_inner_transport_header(skb); | |
41 | } | |
42 | ||
43 | static inline unsigned int inner_tcp_hdrlen(const struct sk_buff *skb) | |
44 | { | |
45 | return inner_tcp_hdr(skb)->doff * 4; | |
46 | } | |
47 | ||
48 | static inline unsigned int tcp_optlen(const struct sk_buff *skb) | |
49 | { | |
50 | return (tcp_hdr(skb)->doff - 5) * 4; | |
51 | } | |
52 | ||
53 | /* TCP Fast Open */ | |
54 | #define TCP_FASTOPEN_COOKIE_MIN 4 /* Min Fast Open Cookie size in bytes */ | |
55 | #define TCP_FASTOPEN_COOKIE_MAX 16 /* Max Fast Open Cookie size in bytes */ | |
56 | #define TCP_FASTOPEN_COOKIE_SIZE 8 /* the size employed by this impl. */ | |
57 | ||
58 | /* TCP Fast Open Cookie as stored in memory */ | |
59 | struct tcp_fastopen_cookie { | |
60 | s8 len; | |
61 | u8 val[TCP_FASTOPEN_COOKIE_MAX]; | |
62 | }; | |
63 | ||
64 | /* This defines a selective acknowledgement block. */ | |
65 | struct tcp_sack_block_wire { | |
66 | __be32 start_seq; | |
67 | __be32 end_seq; | |
68 | }; | |
69 | ||
70 | struct tcp_sack_block { | |
71 | u32 start_seq; | |
72 | u32 end_seq; | |
73 | }; | |
74 | ||
75 | /*These are used to set the sack_ok field in struct tcp_options_received */ | |
76 | #define TCP_SACK_SEEN (1 << 0) /*1 = peer is SACK capable, */ | |
77 | #define TCP_FACK_ENABLED (1 << 1) /*1 = FACK is enabled locally*/ | |
78 | #define TCP_DSACK_SEEN (1 << 2) /*1 = DSACK was received from peer*/ | |
79 | ||
80 | struct tcp_options_received { | |
81 | /* PAWS/RTTM data */ | |
82 | long ts_recent_stamp;/* Time we stored ts_recent (for aging) */ | |
83 | u32 ts_recent; /* Time stamp to echo next */ | |
84 | u32 rcv_tsval; /* Time stamp value */ | |
85 | u32 rcv_tsecr; /* Time stamp echo reply */ | |
86 | u16 saw_tstamp : 1, /* Saw TIMESTAMP on last packet */ | |
87 | tstamp_ok : 1, /* TIMESTAMP seen on SYN packet */ | |
88 | dsack : 1, /* D-SACK is scheduled */ | |
89 | wscale_ok : 1, /* Wscale seen on SYN packet */ | |
90 | sack_ok : 4, /* SACK seen on SYN packet */ | |
91 | snd_wscale : 4, /* Window scaling received from sender */ | |
92 | rcv_wscale : 4; /* Window scaling to send to receiver */ | |
93 | u8 num_sacks; /* Number of SACK blocks */ | |
94 | u16 user_mss; /* mss requested by user in ioctl */ | |
95 | u16 mss_clamp; /* Maximal mss, negotiated at connection setup */ | |
96 | }; | |
97 | ||
98 | static inline void tcp_clear_options(struct tcp_options_received *rx_opt) | |
99 | { | |
100 | rx_opt->tstamp_ok = rx_opt->sack_ok = 0; | |
101 | rx_opt->wscale_ok = rx_opt->snd_wscale = 0; | |
102 | } | |
103 | ||
104 | /* This is the max number of SACKS that we'll generate and process. It's safe | |
105 | * to increase this, although since: | |
106 | * size = TCPOLEN_SACK_BASE_ALIGNED (4) + n * TCPOLEN_SACK_PERBLOCK (8) | |
107 | * only four options will fit in a standard TCP header */ | |
108 | #define TCP_NUM_SACKS 4 | |
109 | ||
110 | struct tcp_request_sock_ops; | |
111 | ||
112 | struct tcp_request_sock { | |
113 | struct inet_request_sock req; | |
114 | const struct tcp_request_sock_ops *af_specific; | |
115 | struct sock *listener; /* needed for TFO */ | |
116 | u32 rcv_isn; | |
117 | u32 snt_isn; | |
118 | u32 snt_synack; /* synack sent time */ | |
119 | u32 rcv_nxt; /* the ack # by SYNACK. For | |
120 | * FastOpen it's the seq# | |
121 | * after data-in-SYN. | |
122 | */ | |
123 | }; | |
124 | ||
125 | static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req) | |
126 | { | |
127 | return (struct tcp_request_sock *)req; | |
128 | } | |
129 | ||
130 | struct tcp_sock { | |
131 | /* inet_connection_sock has to be the first member of tcp_sock */ | |
132 | struct inet_connection_sock inet_conn; | |
133 | u16 tcp_header_len; /* Bytes of tcp header to send */ | |
134 | u16 xmit_size_goal_segs; /* Goal for segmenting output packets */ | |
135 | ||
136 | /* | |
137 | * Header prediction flags | |
138 | * 0x5?10 << 16 + snd_wnd in net byte order | |
139 | */ | |
140 | __be32 pred_flags; | |
141 | ||
142 | /* | |
143 | * RFC793 variables by their proper names. This means you can | |
144 | * read the code and the spec side by side (and laugh ...) | |
145 | * See RFC793 and RFC1122. The RFC writes these in capitals. | |
146 | */ | |
147 | u32 rcv_nxt; /* What we want to receive next */ | |
148 | u32 copied_seq; /* Head of yet unread data */ | |
149 | u32 rcv_wup; /* rcv_nxt on last window update sent */ | |
150 | u32 snd_nxt; /* Next sequence we send */ | |
151 | ||
152 | u32 snd_una; /* First byte we want an ack for */ | |
153 | u32 snd_sml; /* Last byte of the most recently transmitted small packet */ | |
154 | u32 rcv_tstamp; /* timestamp of last received ACK (for keepalives) */ | |
155 | u32 lsndtime; /* timestamp of last sent data packet (for restart window) */ | |
156 | ||
157 | u32 tsoffset; /* timestamp offset */ | |
158 | ||
159 | struct list_head tsq_node; /* anchor in tsq_tasklet.head list */ | |
160 | unsigned long tsq_flags; | |
161 | ||
162 | /* Data for direct copy to user */ | |
163 | struct { | |
164 | struct sk_buff_head prequeue; | |
165 | struct task_struct *task; | |
166 | struct iovec *iov; | |
167 | int memory; | |
168 | int len; | |
169 | #ifdef CONFIG_NET_DMA | |
170 | /* members for async copy */ | |
171 | struct dma_chan *dma_chan; | |
172 | int wakeup; | |
173 | struct dma_pinned_list *pinned_list; | |
174 | dma_cookie_t dma_cookie; | |
175 | #endif | |
176 | } ucopy; | |
177 | ||
178 | u32 snd_wl1; /* Sequence for window update */ | |
179 | u32 snd_wnd; /* The window we expect to receive */ | |
180 | u32 max_window; /* Maximal window ever seen from peer */ | |
181 | u32 mss_cache; /* Cached effective mss, not including SACKS */ | |
182 | ||
183 | u32 window_clamp; /* Maximal window to advertise */ | |
184 | u32 rcv_ssthresh; /* Current window clamp */ | |
185 | ||
186 | u16 advmss; /* Advertised MSS */ | |
187 | u8 unused; | |
188 | u8 nonagle : 4,/* Disable Nagle algorithm? */ | |
189 | thin_lto : 1,/* Use linear timeouts for thin streams */ | |
190 | thin_dupack : 1,/* Fast retransmit on first dupack */ | |
191 | repair : 1, | |
192 | frto : 1;/* F-RTO (RFC5682) activated in CA_Loss */ | |
193 | u8 repair_queue; | |
194 | u8 do_early_retrans:1,/* Enable RFC5827 early-retransmit */ | |
195 | syn_data:1, /* SYN includes data */ | |
196 | syn_fastopen:1, /* SYN includes Fast Open option */ | |
197 | syn_data_acked:1,/* data in SYN is acked by SYN-ACK */ | |
198 | is_cwnd_limited:1;/* forward progress limited by snd_cwnd? */ | |
199 | u32 tlp_high_seq; /* snd_nxt at the time of TLP retransmit. */ | |
200 | ||
201 | /* RTT measurement */ | |
202 | u32 srtt_us; /* smoothed round trip time << 3 in usecs */ | |
203 | u32 mdev_us; /* medium deviation */ | |
204 | u32 mdev_max_us; /* maximal mdev for the last rtt period */ | |
205 | u32 rttvar_us; /* smoothed mdev_max */ | |
206 | u32 rtt_seq; /* sequence number to update rttvar */ | |
207 | ||
208 | u32 packets_out; /* Packets which are "in flight" */ | |
209 | u32 retrans_out; /* Retransmitted packets out */ | |
210 | u32 max_packets_out; /* max packets_out in last window */ | |
211 | u32 max_packets_seq; /* right edge of max_packets_out flight */ | |
212 | ||
213 | u16 urg_data; /* Saved octet of OOB data and control flags */ | |
214 | u8 ecn_flags; /* ECN status bits. */ | |
215 | u8 reordering; /* Packet reordering metric. */ | |
216 | u32 snd_up; /* Urgent pointer */ | |
217 | ||
218 | u8 keepalive_probes; /* num of allowed keep alive probes */ | |
219 | /* | |
220 | * Options received (usually on last packet, some only on SYN packets). | |
221 | */ | |
222 | struct tcp_options_received rx_opt; | |
223 | ||
224 | /* | |
225 | * Slow start and congestion control (see also Nagle, and Karn & Partridge) | |
226 | */ | |
227 | u32 snd_ssthresh; /* Slow start size threshold */ | |
228 | u32 snd_cwnd; /* Sending congestion window */ | |
229 | u32 snd_cwnd_cnt; /* Linear increase counter */ | |
230 | u32 snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */ | |
231 | u32 snd_cwnd_used; | |
232 | u32 snd_cwnd_stamp; | |
233 | u32 prior_cwnd; /* Congestion window at start of Recovery. */ | |
234 | u32 prr_delivered; /* Number of newly delivered packets to | |
235 | * receiver in Recovery. */ | |
236 | u32 prr_out; /* Total number of pkts sent during Recovery. */ | |
237 | ||
238 | u32 rcv_wnd; /* Current receiver window */ | |
239 | u32 write_seq; /* Tail(+1) of data held in tcp send buffer */ | |
240 | u32 notsent_lowat; /* TCP_NOTSENT_LOWAT */ | |
241 | u32 pushed_seq; /* Last pushed seq, required to talk to windows */ | |
242 | u32 lost_out; /* Lost packets */ | |
243 | u32 sacked_out; /* SACK'd packets */ | |
244 | u32 fackets_out; /* FACK'd packets */ | |
245 | u32 tso_deferred; | |
246 | ||
247 | /* from STCP, retrans queue hinting */ | |
248 | struct sk_buff* lost_skb_hint; | |
249 | struct sk_buff *retransmit_skb_hint; | |
250 | ||
251 | /* OOO segments go in this list. Note that socket lock must be held, | |
252 | * as we do not use sk_buff_head lock. | |
253 | */ | |
254 | struct sk_buff_head out_of_order_queue; | |
255 | ||
256 | /* SACKs data, these 2 need to be together (see tcp_options_write) */ | |
257 | struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */ | |
258 | struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/ | |
259 | ||
260 | struct tcp_sack_block recv_sack_cache[4]; | |
261 | ||
262 | struct sk_buff *highest_sack; /* skb just after the highest | |
263 | * skb with SACKed bit set | |
264 | * (validity guaranteed only if | |
265 | * sacked_out > 0) | |
266 | */ | |
267 | ||
268 | int lost_cnt_hint; | |
269 | u32 retransmit_high; /* L-bits may be on up to this seqno */ | |
270 | ||
271 | u32 lost_retrans_low; /* Sent seq after any rxmit (lowest) */ | |
272 | ||
273 | u32 prior_ssthresh; /* ssthresh saved at recovery start */ | |
274 | u32 high_seq; /* snd_nxt at onset of congestion */ | |
275 | ||
276 | u32 retrans_stamp; /* Timestamp of the last retransmit, | |
277 | * also used in SYN-SENT to remember stamp of | |
278 | * the first SYN. */ | |
279 | u32 undo_marker; /* tracking retrans started here. */ | |
280 | int undo_retrans; /* number of undoable retransmissions. */ | |
281 | u32 total_retrans; /* Total retransmits for entire connection */ | |
282 | ||
283 | u32 urg_seq; /* Seq of received urgent pointer */ | |
284 | unsigned int keepalive_time; /* time before keep alive takes place */ | |
285 | unsigned int keepalive_intvl; /* time interval between keep alive probes */ | |
286 | ||
287 | int linger2; | |
288 | ||
289 | /* Receiver side RTT estimation */ | |
290 | struct { | |
291 | u32 rtt; | |
292 | u32 seq; | |
293 | u32 time; | |
294 | } rcv_rtt_est; | |
295 | ||
296 | /* Receiver queue space */ | |
297 | struct { | |
298 | int space; | |
299 | u32 seq; | |
300 | u32 time; | |
301 | } rcvq_space; | |
302 | ||
303 | /* TCP-specific MTU probe information. */ | |
304 | struct { | |
305 | u32 probe_seq_start; | |
306 | u32 probe_seq_end; | |
307 | } mtu_probe; | |
308 | u32 mtu_info; /* We received an ICMP_FRAG_NEEDED / ICMPV6_PKT_TOOBIG | |
309 | * while socket was owned by user. | |
310 | */ | |
311 | ||
312 | #ifdef CONFIG_TCP_MD5SIG | |
313 | /* TCP AF-Specific parts; only used by MD5 Signature support so far */ | |
314 | const struct tcp_sock_af_ops *af_specific; | |
315 | ||
316 | /* TCP MD5 Signature Option information */ | |
317 | struct tcp_md5sig_info __rcu *md5sig_info; | |
318 | #endif | |
319 | ||
320 | /* TCP fastopen related information */ | |
321 | struct tcp_fastopen_request *fastopen_req; | |
322 | /* fastopen_rsk points to request_sock that resulted in this big | |
323 | * socket. Used to retransmit SYNACKs etc. | |
324 | */ | |
325 | struct request_sock *fastopen_rsk; | |
326 | }; | |
327 | ||
328 | enum tsq_flags { | |
329 | TSQ_THROTTLED, | |
330 | TSQ_QUEUED, | |
331 | TCP_TSQ_DEFERRED, /* tcp_tasklet_func() found socket was owned */ | |
332 | TCP_WRITE_TIMER_DEFERRED, /* tcp_write_timer() found socket was owned */ | |
333 | TCP_DELACK_TIMER_DEFERRED, /* tcp_delack_timer() found socket was owned */ | |
334 | TCP_MTU_REDUCED_DEFERRED, /* tcp_v{4|6}_err() could not call | |
335 | * tcp_v{4|6}_mtu_reduced() | |
336 | */ | |
337 | }; | |
338 | ||
339 | static inline struct tcp_sock *tcp_sk(const struct sock *sk) | |
340 | { | |
341 | return (struct tcp_sock *)sk; | |
342 | } | |
343 | ||
344 | struct tcp_timewait_sock { | |
345 | struct inet_timewait_sock tw_sk; | |
346 | u32 tw_rcv_nxt; | |
347 | u32 tw_snd_nxt; | |
348 | u32 tw_rcv_wnd; | |
349 | u32 tw_ts_offset; | |
350 | u32 tw_ts_recent; | |
351 | long tw_ts_recent_stamp; | |
352 | #ifdef CONFIG_TCP_MD5SIG | |
353 | struct tcp_md5sig_key *tw_md5_key; | |
354 | #endif | |
355 | }; | |
356 | ||
357 | static inline struct tcp_timewait_sock *tcp_twsk(const struct sock *sk) | |
358 | { | |
359 | return (struct tcp_timewait_sock *)sk; | |
360 | } | |
361 | ||
362 | static inline bool tcp_passive_fastopen(const struct sock *sk) | |
363 | { | |
364 | return (sk->sk_state == TCP_SYN_RECV && | |
365 | tcp_sk(sk)->fastopen_rsk != NULL); | |
366 | } | |
367 | ||
368 | extern void tcp_sock_destruct(struct sock *sk); | |
369 | ||
370 | static inline int fastopen_init_queue(struct sock *sk, int backlog) | |
371 | { | |
372 | struct request_sock_queue *queue = | |
373 | &inet_csk(sk)->icsk_accept_queue; | |
374 | ||
375 | if (queue->fastopenq == NULL) { | |
376 | queue->fastopenq = kzalloc( | |
377 | sizeof(struct fastopen_queue), | |
378 | sk->sk_allocation); | |
379 | if (queue->fastopenq == NULL) | |
380 | return -ENOMEM; | |
381 | ||
382 | sk->sk_destruct = tcp_sock_destruct; | |
383 | spin_lock_init(&queue->fastopenq->lock); | |
384 | } | |
385 | queue->fastopenq->max_qlen = backlog; | |
386 | return 0; | |
387 | } | |
388 | ||
389 | #endif /* _LINUX_TCP_H */ |