syncookies.c (eed29f17f09ad7f400bc245f209acad6a8214fac) syncookies.c (f930103421f6579719b8252285c94c1195f6e032)
1/*
2 * Syncookies implementation for the Linux kernel
3 *
4 * Copyright (C) 1997 Andi Kleen
5 * Based on ideas by D.J.Bernstein and Eric Schenk.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License

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227/*
228 * when syncookies are in effect and tcp timestamps are enabled we stored
229 * additional tcp options in the timestamp.
230 * This extracts these options from the timestamp echo.
231 *
232 * return false if we decode a tcp option that is disabled
233 * on the host.
234 */
1/*
2 * Syncookies implementation for the Linux kernel
3 *
4 * Copyright (C) 1997 Andi Kleen
5 * Based on ideas by D.J.Bernstein and Eric Schenk.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License

--- 218 unchanged lines hidden (view full) ---

227/*
228 * when syncookies are in effect and tcp timestamps are enabled we stored
229 * additional tcp options in the timestamp.
230 * This extracts these options from the timestamp echo.
231 *
232 * return false if we decode a tcp option that is disabled
233 * on the host.
234 */
235bool cookie_timestamp_decode(struct tcp_options_received *tcp_opt)
235bool cookie_timestamp_decode(const struct net *net,
236 struct tcp_options_received *tcp_opt)
236{
237 /* echoed timestamp, lowest bits contain options */
238 u32 options = tcp_opt->rcv_tsecr;
239
240 if (!tcp_opt->saw_tstamp) {
241 tcp_clear_options(tcp_opt);
242 return true;
243 }
244
245 if (!sysctl_tcp_timestamps)
246 return false;
247
248 tcp_opt->sack_ok = (options & TS_OPT_SACK) ? TCP_SACK_SEEN : 0;
249
237{
238 /* echoed timestamp, lowest bits contain options */
239 u32 options = tcp_opt->rcv_tsecr;
240
241 if (!tcp_opt->saw_tstamp) {
242 tcp_clear_options(tcp_opt);
243 return true;
244 }
245
246 if (!sysctl_tcp_timestamps)
247 return false;
248
249 tcp_opt->sack_ok = (options & TS_OPT_SACK) ? TCP_SACK_SEEN : 0;
250
250 if (tcp_opt->sack_ok && !sysctl_tcp_sack)
251 if (tcp_opt->sack_ok && !net->ipv4.sysctl_tcp_sack)
251 return false;
252
253 if ((options & TS_OPT_WSCALE_MASK) == TS_OPT_WSCALE_MASK)
254 return true; /* no window scaling */
255
256 tcp_opt->wscale_ok = 1;
257 tcp_opt->snd_wscale = options & TS_OPT_WSCALE_MASK;
258

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314 memset(&tcp_opt, 0, sizeof(tcp_opt));
315 tcp_parse_options(sock_net(sk), skb, &tcp_opt, 0, NULL);
316
317 if (tcp_opt.saw_tstamp && tcp_opt.rcv_tsecr) {
318 tsoff = secure_tcp_ts_off(ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
319 tcp_opt.rcv_tsecr -= tsoff;
320 }
321
252 return false;
253
254 if ((options & TS_OPT_WSCALE_MASK) == TS_OPT_WSCALE_MASK)
255 return true; /* no window scaling */
256
257 tcp_opt->wscale_ok = 1;
258 tcp_opt->snd_wscale = options & TS_OPT_WSCALE_MASK;
259

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315 memset(&tcp_opt, 0, sizeof(tcp_opt));
316 tcp_parse_options(sock_net(sk), skb, &tcp_opt, 0, NULL);
317
318 if (tcp_opt.saw_tstamp && tcp_opt.rcv_tsecr) {
319 tsoff = secure_tcp_ts_off(ip_hdr(skb)->daddr, ip_hdr(skb)->saddr);
320 tcp_opt.rcv_tsecr -= tsoff;
321 }
322
322 if (!cookie_timestamp_decode(&tcp_opt))
323 if (!cookie_timestamp_decode(sock_net(sk), &tcp_opt))
323 goto out;
324
325 ret = NULL;
326 req = inet_reqsk_alloc(&tcp_request_sock_ops, sk, false); /* for safety */
327 if (!req)
328 goto out;
329
330 ireq = inet_rsk(req);

--- 69 unchanged lines hidden --- 		324 goto out;
325
326 ret = NULL;
327 req = inet_reqsk_alloc(&tcp_request_sock_ops, sk, false); /* for safety */
328 if (!req)
329 goto out;
330
331 ireq = inet_rsk(req);

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