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Commit | Line | Data |
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cf80e0e4 | 1 | #include <linux/crypto.h> |
10467163 | 2 | #include <linux/err.h> |
2100c8d2 YC |
3 | #include <linux/init.h> |
4 | #include <linux/kernel.h> | |
10467163 JC |
5 | #include <linux/list.h> |
6 | #include <linux/tcp.h> | |
7 | #include <linux/rcupdate.h> | |
8 | #include <linux/rculist.h> | |
9 | #include <net/inetpeer.h> | |
10 | #include <net/tcp.h> | |
2100c8d2 | 11 | |
43713848 | 12 | void tcp_fastopen_init_key_once(struct net *net) |
222e83d2 | 13 | { |
43713848 HY |
14 | u8 key[TCP_FASTOPEN_KEY_LENGTH]; |
15 | struct tcp_fastopen_context *ctxt; | |
16 | ||
17 | rcu_read_lock(); | |
18 | ctxt = rcu_dereference(net->ipv4.tcp_fastopen_ctx); | |
19 | if (ctxt) { | |
20 | rcu_read_unlock(); | |
21 | return; | |
22 | } | |
23 | rcu_read_unlock(); | |
222e83d2 HFS |
24 | |
25 | /* tcp_fastopen_reset_cipher publishes the new context | |
26 | * atomically, so we allow this race happening here. | |
27 | * | |
28 | * All call sites of tcp_fastopen_cookie_gen also check | |
29 | * for a valid cookie, so this is an acceptable risk. | |
30 | */ | |
43713848 HY |
31 | get_random_bytes(key, sizeof(key)); |
32 | tcp_fastopen_reset_cipher(net, key, sizeof(key)); | |
222e83d2 HFS |
33 | } |
34 | ||
10467163 JC |
35 | static void tcp_fastopen_ctx_free(struct rcu_head *head) |
36 | { | |
37 | struct tcp_fastopen_context *ctx = | |
38 | container_of(head, struct tcp_fastopen_context, rcu); | |
39 | crypto_free_cipher(ctx->tfm); | |
40 | kfree(ctx); | |
41 | } | |
42 | ||
43713848 HY |
43 | void tcp_fastopen_ctx_destroy(struct net *net) |
44 | { | |
45 | struct tcp_fastopen_context *ctxt; | |
46 | ||
47 | spin_lock(&net->ipv4.tcp_fastopen_ctx_lock); | |
48 | ||
49 | ctxt = rcu_dereference_protected(net->ipv4.tcp_fastopen_ctx, | |
50 | lockdep_is_held(&net->ipv4.tcp_fastopen_ctx_lock)); | |
51 | rcu_assign_pointer(net->ipv4.tcp_fastopen_ctx, NULL); | |
52 | spin_unlock(&net->ipv4.tcp_fastopen_ctx_lock); | |
53 | ||
54 | if (ctxt) | |
55 | call_rcu(&ctxt->rcu, tcp_fastopen_ctx_free); | |
56 | } | |
57 | ||
58 | int tcp_fastopen_reset_cipher(struct net *net, void *key, unsigned int len) | |
10467163 JC |
59 | { |
60 | int err; | |
61 | struct tcp_fastopen_context *ctx, *octx; | |
62 | ||
63 | ctx = kmalloc(sizeof(*ctx), GFP_KERNEL); | |
64 | if (!ctx) | |
65 | return -ENOMEM; | |
66 | ctx->tfm = crypto_alloc_cipher("aes", 0, 0); | |
67 | ||
68 | if (IS_ERR(ctx->tfm)) { | |
69 | err = PTR_ERR(ctx->tfm); | |
70 | error: kfree(ctx); | |
71 | pr_err("TCP: TFO aes cipher alloc error: %d\n", err); | |
72 | return err; | |
73 | } | |
74 | err = crypto_cipher_setkey(ctx->tfm, key, len); | |
75 | if (err) { | |
76 | pr_err("TCP: TFO cipher key error: %d\n", err); | |
77 | crypto_free_cipher(ctx->tfm); | |
78 | goto error; | |
79 | } | |
80 | memcpy(ctx->key, key, len); | |
81 | ||
43713848 | 82 | spin_lock(&net->ipv4.tcp_fastopen_ctx_lock); |
10467163 | 83 | |
43713848 HY |
84 | octx = rcu_dereference_protected(net->ipv4.tcp_fastopen_ctx, |
85 | lockdep_is_held(&net->ipv4.tcp_fastopen_ctx_lock)); | |
86 | rcu_assign_pointer(net->ipv4.tcp_fastopen_ctx, ctx); | |
87 | spin_unlock(&net->ipv4.tcp_fastopen_ctx_lock); | |
10467163 JC |
88 | |
89 | if (octx) | |
90 | call_rcu(&octx->rcu, tcp_fastopen_ctx_free); | |
91 | return err; | |
92 | } | |
93 | ||
43713848 HY |
94 | static bool __tcp_fastopen_cookie_gen(struct net *net, |
95 | const void *path, | |
3a19ce0e | 96 | struct tcp_fastopen_cookie *foc) |
10467163 | 97 | { |
10467163 | 98 | struct tcp_fastopen_context *ctx; |
3a19ce0e | 99 | bool ok = false; |
10467163 JC |
100 | |
101 | rcu_read_lock(); | |
43713848 | 102 | ctx = rcu_dereference(net->ipv4.tcp_fastopen_ctx); |
10467163 | 103 | if (ctx) { |
3a19ce0e | 104 | crypto_cipher_encrypt_one(ctx->tfm, foc->val, path); |
10467163 | 105 | foc->len = TCP_FASTOPEN_COOKIE_SIZE; |
3a19ce0e | 106 | ok = true; |
10467163 JC |
107 | } |
108 | rcu_read_unlock(); | |
3a19ce0e DL |
109 | return ok; |
110 | } | |
111 | ||
112 | /* Generate the fastopen cookie by doing aes128 encryption on both | |
113 | * the source and destination addresses. Pad 0s for IPv4 or IPv4-mapped-IPv6 | |
114 | * addresses. For the longer IPv6 addresses use CBC-MAC. | |
115 | * | |
116 | * XXX (TFO) - refactor when TCP_FASTOPEN_COOKIE_SIZE != AES_BLOCK_SIZE. | |
117 | */ | |
43713848 HY |
118 | static bool tcp_fastopen_cookie_gen(struct net *net, |
119 | struct request_sock *req, | |
3a19ce0e DL |
120 | struct sk_buff *syn, |
121 | struct tcp_fastopen_cookie *foc) | |
122 | { | |
123 | if (req->rsk_ops->family == AF_INET) { | |
124 | const struct iphdr *iph = ip_hdr(syn); | |
125 | ||
126 | __be32 path[4] = { iph->saddr, iph->daddr, 0, 0 }; | |
43713848 | 127 | return __tcp_fastopen_cookie_gen(net, path, foc); |
3a19ce0e DL |
128 | } |
129 | ||
130 | #if IS_ENABLED(CONFIG_IPV6) | |
131 | if (req->rsk_ops->family == AF_INET6) { | |
132 | const struct ipv6hdr *ip6h = ipv6_hdr(syn); | |
133 | struct tcp_fastopen_cookie tmp; | |
134 | ||
43713848 | 135 | if (__tcp_fastopen_cookie_gen(net, &ip6h->saddr, &tmp)) { |
003c9410 | 136 | struct in6_addr *buf = &tmp.addr; |
41c91996 | 137 | int i; |
3a19ce0e DL |
138 | |
139 | for (i = 0; i < 4; i++) | |
140 | buf->s6_addr32[i] ^= ip6h->daddr.s6_addr32[i]; | |
43713848 | 141 | return __tcp_fastopen_cookie_gen(net, buf, foc); |
3a19ce0e DL |
142 | } |
143 | } | |
144 | #endif | |
145 | return false; | |
10467163 | 146 | } |
5b7ed089 | 147 | |
61d2bcae ED |
148 | |
149 | /* If an incoming SYN or SYNACK frame contains a payload and/or FIN, | |
150 | * queue this additional data / FIN. | |
151 | */ | |
152 | void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb) | |
153 | { | |
154 | struct tcp_sock *tp = tcp_sk(sk); | |
155 | ||
156 | if (TCP_SKB_CB(skb)->end_seq == tp->rcv_nxt) | |
157 | return; | |
158 | ||
159 | skb = skb_clone(skb, GFP_ATOMIC); | |
160 | if (!skb) | |
161 | return; | |
162 | ||
163 | skb_dst_drop(skb); | |
a44d6eac MKL |
164 | /* segs_in has been initialized to 1 in tcp_create_openreq_child(). |
165 | * Hence, reset segs_in to 0 before calling tcp_segs_in() | |
166 | * to avoid double counting. Also, tcp_segs_in() expects | |
167 | * skb->len to include the tcp_hdrlen. Hence, it should | |
168 | * be called before __skb_pull(). | |
169 | */ | |
170 | tp->segs_in = 0; | |
171 | tcp_segs_in(tp, skb); | |
61d2bcae | 172 | __skb_pull(skb, tcp_hdrlen(skb)); |
76061f63 | 173 | sk_forced_mem_schedule(sk, skb->truesize); |
61d2bcae ED |
174 | skb_set_owner_r(skb, sk); |
175 | ||
9d691539 ED |
176 | TCP_SKB_CB(skb)->seq++; |
177 | TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_SYN; | |
178 | ||
61d2bcae ED |
179 | tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq; |
180 | __skb_queue_tail(&sk->sk_receive_queue, skb); | |
181 | tp->syn_data_acked = 1; | |
182 | ||
183 | /* u64_stats_update_begin(&tp->syncp) not needed here, | |
184 | * as we certainly are not changing upper 32bit value (0) | |
185 | */ | |
186 | tp->bytes_received = skb->len; | |
e3e17b77 ED |
187 | |
188 | if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) | |
189 | tcp_fin(sk); | |
61d2bcae ED |
190 | } |
191 | ||
7c85af88 ED |
192 | static struct sock *tcp_fastopen_create_child(struct sock *sk, |
193 | struct sk_buff *skb, | |
7c85af88 | 194 | struct request_sock *req) |
5b7ed089 | 195 | { |
17846376 | 196 | struct tcp_sock *tp; |
5b7ed089 | 197 | struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue; |
5b7ed089 | 198 | struct sock *child; |
5e0724d0 | 199 | bool own_req; |
5b7ed089 YC |
200 | |
201 | req->num_retrans = 0; | |
202 | req->num_timeout = 0; | |
203 | req->sk = NULL; | |
204 | ||
5e0724d0 ED |
205 | child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL, |
206 | NULL, &own_req); | |
51456b29 | 207 | if (!child) |
7c85af88 | 208 | return NULL; |
5b7ed089 | 209 | |
0536fcc0 ED |
210 | spin_lock(&queue->fastopenq.lock); |
211 | queue->fastopenq.qlen++; | |
212 | spin_unlock(&queue->fastopenq.lock); | |
5b7ed089 YC |
213 | |
214 | /* Initialize the child socket. Have to fix some values to take | |
215 | * into account the child is a Fast Open socket and is created | |
216 | * only out of the bits carried in the SYN packet. | |
217 | */ | |
218 | tp = tcp_sk(child); | |
219 | ||
220 | tp->fastopen_rsk = req; | |
9439ce00 | 221 | tcp_rsk(req)->tfo_listener = true; |
5b7ed089 YC |
222 | |
223 | /* RFC1323: The window in SYN & SYN/ACK segments is never | |
224 | * scaled. So correct it appropriately. | |
225 | */ | |
226 | tp->snd_wnd = ntohs(tcp_hdr(skb)->window); | |
0dbd7ff3 | 227 | tp->max_window = tp->snd_wnd; |
5b7ed089 YC |
228 | |
229 | /* Activate the retrans timer so that SYNACK can be retransmitted. | |
ca6fb065 | 230 | * The request socket is not added to the ehash |
5b7ed089 YC |
231 | * because it's been added to the accept queue directly. |
232 | */ | |
233 | inet_csk_reset_xmit_timer(child, ICSK_TIME_RETRANS, | |
234 | TCP_TIMEOUT_INIT, TCP_RTO_MAX); | |
235 | ||
41c6d650 | 236 | refcount_set(&req->rsk_refcnt, 2); |
5b7ed089 YC |
237 | |
238 | /* Now finish processing the fastopen child socket. */ | |
27204aaa | 239 | tcp_init_transfer(child, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB); |
5b7ed089 | 240 | |
61d2bcae ED |
241 | tp->rcv_nxt = TCP_SKB_CB(skb)->seq + 1; |
242 | ||
243 | tcp_fastopen_add_skb(child, skb); | |
244 | ||
245 | tcp_rsk(req)->rcv_nxt = tp->rcv_nxt; | |
28b346cb | 246 | tp->rcv_wup = tp->rcv_nxt; |
7656d842 ED |
247 | /* tcp_conn_request() is sending the SYNACK, |
248 | * and queues the child into listener accept queue. | |
7c85af88 | 249 | */ |
7c85af88 | 250 | return child; |
5b7ed089 | 251 | } |
5b7ed089 YC |
252 | |
253 | static bool tcp_fastopen_queue_check(struct sock *sk) | |
254 | { | |
255 | struct fastopen_queue *fastopenq; | |
256 | ||
257 | /* Make sure the listener has enabled fastopen, and we don't | |
258 | * exceed the max # of pending TFO requests allowed before trying | |
259 | * to validating the cookie in order to avoid burning CPU cycles | |
260 | * unnecessarily. | |
261 | * | |
262 | * XXX (TFO) - The implication of checking the max_qlen before | |
263 | * processing a cookie request is that clients can't differentiate | |
264 | * between qlen overflow causing Fast Open to be disabled | |
265 | * temporarily vs a server not supporting Fast Open at all. | |
266 | */ | |
0536fcc0 ED |
267 | fastopenq = &inet_csk(sk)->icsk_accept_queue.fastopenq; |
268 | if (fastopenq->max_qlen == 0) | |
5b7ed089 YC |
269 | return false; |
270 | ||
271 | if (fastopenq->qlen >= fastopenq->max_qlen) { | |
272 | struct request_sock *req1; | |
273 | spin_lock(&fastopenq->lock); | |
274 | req1 = fastopenq->rskq_rst_head; | |
fa76ce73 | 275 | if (!req1 || time_after(req1->rsk_timer.expires, jiffies)) { |
02a1d6e7 ED |
276 | __NET_INC_STATS(sock_net(sk), |
277 | LINUX_MIB_TCPFASTOPENLISTENOVERFLOW); | |
c10d9310 | 278 | spin_unlock(&fastopenq->lock); |
5b7ed089 YC |
279 | return false; |
280 | } | |
281 | fastopenq->rskq_rst_head = req1->dl_next; | |
282 | fastopenq->qlen--; | |
283 | spin_unlock(&fastopenq->lock); | |
13854e5a | 284 | reqsk_put(req1); |
5b7ed089 YC |
285 | } |
286 | return true; | |
287 | } | |
288 | ||
89278c9d YC |
289 | /* Returns true if we should perform Fast Open on the SYN. The cookie (foc) |
290 | * may be updated and return the client in the SYN-ACK later. E.g., Fast Open | |
291 | * cookie request (foc->len == 0). | |
292 | */ | |
7c85af88 ED |
293 | struct sock *tcp_try_fastopen(struct sock *sk, struct sk_buff *skb, |
294 | struct request_sock *req, | |
11199369 | 295 | struct tcp_fastopen_cookie *foc) |
5b7ed089 | 296 | { |
89278c9d | 297 | bool syn_data = TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq + 1; |
e1cfcbe8 HY |
298 | int tcp_fastopen = sock_net(sk)->ipv4.sysctl_tcp_fastopen; |
299 | struct tcp_fastopen_cookie valid_foc = { .len = -1 }; | |
7c85af88 | 300 | struct sock *child; |
5b7ed089 | 301 | |
531c94a9 | 302 | if (foc->len == 0) /* Client requests a cookie */ |
c10d9310 | 303 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENCOOKIEREQD); |
531c94a9 | 304 | |
e1cfcbe8 | 305 | if (!((tcp_fastopen & TFO_SERVER_ENABLE) && |
89278c9d YC |
306 | (syn_data || foc->len >= 0) && |
307 | tcp_fastopen_queue_check(sk))) { | |
308 | foc->len = -1; | |
7c85af88 | 309 | return NULL; |
5b7ed089 YC |
310 | } |
311 | ||
e1cfcbe8 | 312 | if (syn_data && (tcp_fastopen & TFO_SERVER_COOKIE_NOT_REQD)) |
89278c9d YC |
313 | goto fastopen; |
314 | ||
531c94a9 | 315 | if (foc->len >= 0 && /* Client presents or requests a cookie */ |
43713848 | 316 | tcp_fastopen_cookie_gen(sock_net(sk), req, skb, &valid_foc) && |
3a19ce0e | 317 | foc->len == TCP_FASTOPEN_COOKIE_SIZE && |
89278c9d YC |
318 | foc->len == valid_foc.len && |
319 | !memcmp(foc->val, valid_foc.val, foc->len)) { | |
843f4a55 YC |
320 | /* Cookie is valid. Create a (full) child socket to accept |
321 | * the data in SYN before returning a SYN-ACK to ack the | |
322 | * data. If we fail to create the socket, fall back and | |
323 | * ack the ISN only but includes the same cookie. | |
324 | * | |
325 | * Note: Data-less SYN with valid cookie is allowed to send | |
326 | * data in SYN_RECV state. | |
327 | */ | |
89278c9d | 328 | fastopen: |
11199369 | 329 | child = tcp_fastopen_create_child(sk, skb, req); |
7c85af88 | 330 | if (child) { |
843f4a55 | 331 | foc->len = -1; |
c10d9310 ED |
332 | NET_INC_STATS(sock_net(sk), |
333 | LINUX_MIB_TCPFASTOPENPASSIVE); | |
7c85af88 | 334 | return child; |
843f4a55 | 335 | } |
c10d9310 | 336 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENPASSIVEFAIL); |
531c94a9 | 337 | } else if (foc->len > 0) /* Client presents an invalid cookie */ |
c10d9310 | 338 | NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPFASTOPENPASSIVEFAIL); |
89278c9d | 339 | |
7f9b838b | 340 | valid_foc.exp = foc->exp; |
89278c9d | 341 | *foc = valid_foc; |
7c85af88 | 342 | return NULL; |
5b7ed089 | 343 | } |
065263f4 WW |
344 | |
345 | bool tcp_fastopen_cookie_check(struct sock *sk, u16 *mss, | |
346 | struct tcp_fastopen_cookie *cookie) | |
347 | { | |
348 | unsigned long last_syn_loss = 0; | |
349 | int syn_loss = 0; | |
350 | ||
351 | tcp_fastopen_cache_get(sk, mss, cookie, &syn_loss, &last_syn_loss); | |
352 | ||
353 | /* Recurring FO SYN losses: no cookie or data in SYN */ | |
354 | if (syn_loss > 1 && | |
355 | time_before(jiffies, last_syn_loss + (60*HZ << syn_loss))) { | |
356 | cookie->len = -1; | |
357 | return false; | |
358 | } | |
cf1ef3f0 WW |
359 | |
360 | /* Firewall blackhole issue check */ | |
361 | if (tcp_fastopen_active_should_disable(sk)) { | |
362 | cookie->len = -1; | |
363 | return false; | |
364 | } | |
365 | ||
e1cfcbe8 | 366 | if (sock_net(sk)->ipv4.sysctl_tcp_fastopen & TFO_CLIENT_NO_COOKIE) { |
065263f4 WW |
367 | cookie->len = -1; |
368 | return true; | |
369 | } | |
370 | return cookie->len > 0; | |
371 | } | |
19f6d3f3 WW |
372 | |
373 | /* This function checks if we want to defer sending SYN until the first | |
374 | * write(). We defer under the following conditions: | |
375 | * 1. fastopen_connect sockopt is set | |
376 | * 2. we have a valid cookie | |
377 | * Return value: return true if we want to defer until application writes data | |
378 | * return false if we want to send out SYN immediately | |
379 | */ | |
380 | bool tcp_fastopen_defer_connect(struct sock *sk, int *err) | |
381 | { | |
382 | struct tcp_fastopen_cookie cookie = { .len = 0 }; | |
383 | struct tcp_sock *tp = tcp_sk(sk); | |
384 | u16 mss; | |
385 | ||
386 | if (tp->fastopen_connect && !tp->fastopen_req) { | |
387 | if (tcp_fastopen_cookie_check(sk, &mss, &cookie)) { | |
388 | inet_sk(sk)->defer_connect = 1; | |
389 | return true; | |
390 | } | |
391 | ||
392 | /* Alloc fastopen_req in order for FO option to be included | |
393 | * in SYN | |
394 | */ | |
395 | tp->fastopen_req = kzalloc(sizeof(*tp->fastopen_req), | |
396 | sk->sk_allocation); | |
397 | if (tp->fastopen_req) | |
398 | tp->fastopen_req->cookie = cookie; | |
399 | else | |
400 | *err = -ENOBUFS; | |
401 | } | |
402 | return false; | |
403 | } | |
404 | EXPORT_SYMBOL(tcp_fastopen_defer_connect); | |
cf1ef3f0 WW |
405 | |
406 | /* | |
407 | * The following code block is to deal with middle box issues with TFO: | |
408 | * Middlebox firewall issues can potentially cause server's data being | |
409 | * blackholed after a successful 3WHS using TFO. | |
410 | * The proposed solution is to disable active TFO globally under the | |
411 | * following circumstances: | |
412 | * 1. client side TFO socket receives out of order FIN | |
413 | * 2. client side TFO socket receives out of order RST | |
414 | * We disable active side TFO globally for 1hr at first. Then if it | |
415 | * happens again, we disable it for 2h, then 4h, 8h, ... | |
416 | * And we reset the timeout back to 1hr when we see a successful active | |
417 | * TFO connection with data exchanges. | |
418 | */ | |
419 | ||
cf1ef3f0 WW |
420 | /* Disable active TFO and record current jiffies and |
421 | * tfo_active_disable_times | |
422 | */ | |
46c2fa39 | 423 | void tcp_fastopen_active_disable(struct sock *sk) |
cf1ef3f0 | 424 | { |
3733be14 | 425 | struct net *net = sock_net(sk); |
cf1ef3f0 | 426 | |
3733be14 HY |
427 | atomic_inc(&net->ipv4.tfo_active_disable_times); |
428 | net->ipv4.tfo_active_disable_stamp = jiffies; | |
429 | NET_INC_STATS(net, LINUX_MIB_TCPFASTOPENBLACKHOLE); | |
cf1ef3f0 WW |
430 | } |
431 | ||
432 | /* Calculate timeout for tfo active disable | |
433 | * Return true if we are still in the active TFO disable period | |
434 | * Return false if timeout already expired and we should use active TFO | |
435 | */ | |
436 | bool tcp_fastopen_active_should_disable(struct sock *sk) | |
437 | { | |
3733be14 HY |
438 | unsigned int tfo_bh_timeout = sock_net(sk)->ipv4.sysctl_tcp_fastopen_blackhole_timeout; |
439 | int tfo_da_times = atomic_read(&sock_net(sk)->ipv4.tfo_active_disable_times); | |
cf1ef3f0 | 440 | unsigned long timeout; |
3733be14 | 441 | int multiplier; |
cf1ef3f0 WW |
442 | |
443 | if (!tfo_da_times) | |
444 | return false; | |
445 | ||
446 | /* Limit timout to max: 2^6 * initial timeout */ | |
447 | multiplier = 1 << min(tfo_da_times - 1, 6); | |
3733be14 HY |
448 | timeout = multiplier * tfo_bh_timeout * HZ; |
449 | if (time_before(jiffies, sock_net(sk)->ipv4.tfo_active_disable_stamp + timeout)) | |
cf1ef3f0 WW |
450 | return true; |
451 | ||
452 | /* Mark check bit so we can check for successful active TFO | |
453 | * condition and reset tfo_active_disable_times | |
454 | */ | |
455 | tcp_sk(sk)->syn_fastopen_ch = 1; | |
456 | return false; | |
457 | } | |
458 | ||
459 | /* Disable active TFO if FIN is the only packet in the ofo queue | |
460 | * and no data is received. | |
461 | * Also check if we can reset tfo_active_disable_times if data is | |
462 | * received successfully on a marked active TFO sockets opened on | |
463 | * a non-loopback interface | |
464 | */ | |
465 | void tcp_fastopen_active_disable_ofo_check(struct sock *sk) | |
466 | { | |
467 | struct tcp_sock *tp = tcp_sk(sk); | |
cf1ef3f0 | 468 | struct dst_entry *dst; |
18a4c0ea | 469 | struct sk_buff *skb; |
cf1ef3f0 WW |
470 | |
471 | if (!tp->syn_fastopen) | |
472 | return; | |
473 | ||
474 | if (!tp->data_segs_in) { | |
18a4c0ea ED |
475 | skb = skb_rb_first(&tp->out_of_order_queue); |
476 | if (skb && !skb_rb_next(skb)) { | |
cf1ef3f0 | 477 | if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) { |
46c2fa39 | 478 | tcp_fastopen_active_disable(sk); |
cf1ef3f0 WW |
479 | return; |
480 | } | |
481 | } | |
482 | } else if (tp->syn_fastopen_ch && | |
3733be14 | 483 | atomic_read(&sock_net(sk)->ipv4.tfo_active_disable_times)) { |
cf1ef3f0 WW |
484 | dst = sk_dst_get(sk); |
485 | if (!(dst && dst->dev && (dst->dev->flags & IFF_LOOPBACK))) | |
3733be14 | 486 | atomic_set(&sock_net(sk)->ipv4.tfo_active_disable_times, 0); |
cf1ef3f0 WW |
487 | dst_release(dst); |
488 | } | |
489 | } |