| 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 | * Implementation of the Transmission Control Protocol(TCP). |
| 7 | * |
| 8 | * IPv4 specific functions |
| 9 | * |
| 10 | * |
| 11 | * code split from: |
| 12 | * linux/ipv4/tcp.c |
| 13 | * linux/ipv4/tcp_input.c |
| 14 | * linux/ipv4/tcp_output.c |
| 15 | * |
| 16 | * See tcp.c for author information |
| 17 | * |
| 18 | * This program is free software; you can redistribute it and/or |
| 19 | * modify it under the terms of the GNU General Public License |
| 20 | * as published by the Free Software Foundation; either version |
| 21 | * 2 of the License, or (at your option) any later version. |
| 22 | */ |
| 23 | |
| 24 | /* |
| 25 | * Changes: |
| 26 | * David S. Miller : New socket lookup architecture. |
| 27 | * This code is dedicated to John Dyson. |
| 28 | * David S. Miller : Change semantics of established hash, |
| 29 | * half is devoted to TIME_WAIT sockets |
| 30 | * and the rest go in the other half. |
| 31 | * Andi Kleen : Add support for syncookies and fixed |
| 32 | * some bugs: ip options weren't passed to |
| 33 | * the TCP layer, missed a check for an |
| 34 | * ACK bit. |
| 35 | * Andi Kleen : Implemented fast path mtu discovery. |
| 36 | * Fixed many serious bugs in the |
| 37 | * request_sock handling and moved |
| 38 | * most of it into the af independent code. |
| 39 | * Added tail drop and some other bugfixes. |
| 40 | * Added new listen semantics. |
| 41 | * Mike McLagan : Routing by source |
| 42 | * Juan Jose Ciarlante: ip_dynaddr bits |
| 43 | * Andi Kleen: various fixes. |
| 44 | * Vitaly E. Lavrov : Transparent proxy revived after year |
| 45 | * coma. |
| 46 | * Andi Kleen : Fix new listen. |
| 47 | * Andi Kleen : Fix accept error reporting. |
| 48 | * YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which |
| 49 | * Alexey Kuznetsov allow both IPv4 and IPv6 sockets to bind |
| 50 | * a single port at the same time. |
| 51 | */ |
| 52 | |
| 53 | #define pr_fmt(fmt) "TCP: " fmt |
| 54 | |
| 55 | #include <linux/bottom_half.h> |
| 56 | #include <linux/types.h> |
| 57 | #include <linux/fcntl.h> |
| 58 | #include <linux/module.h> |
| 59 | #include <linux/random.h> |
| 60 | #include <linux/cache.h> |
| 61 | #include <linux/jhash.h> |
| 62 | #include <linux/init.h> |
| 63 | #include <linux/times.h> |
| 64 | #include <linux/slab.h> |
| 65 | |
| 66 | #include <net/net_namespace.h> |
| 67 | #include <net/icmp.h> |
| 68 | #include <net/inet_hashtables.h> |
| 69 | #include <net/tcp.h> |
| 70 | #include <net/transp_v6.h> |
| 71 | #include <net/ipv6.h> |
| 72 | #include <net/inet_common.h> |
| 73 | #include <net/timewait_sock.h> |
| 74 | #include <net/xfrm.h> |
| 75 | #include <net/secure_seq.h> |
| 76 | #include <net/busy_poll.h> |
| 77 | |
| 78 | #include <linux/inet.h> |
| 79 | #include <linux/ipv6.h> |
| 80 | #include <linux/stddef.h> |
| 81 | #include <linux/proc_fs.h> |
| 82 | #include <linux/seq_file.h> |
| 83 | |
| 84 | #include <crypto/hash.h> |
| 85 | #include <linux/scatterlist.h> |
| 86 | |
| 87 | int sysctl_tcp_tw_reuse __read_mostly; |
| 88 | int sysctl_tcp_low_latency __read_mostly; |
| 89 | EXPORT_SYMBOL(sysctl_tcp_low_latency); |
| 90 | |
| 91 | #ifdef CONFIG_TCP_MD5SIG |
| 92 | static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, |
| 93 | __be32 daddr, __be32 saddr, const struct tcphdr *th); |
| 94 | #endif |
| 95 | |
| 96 | struct inet_hashinfo tcp_hashinfo; |
| 97 | EXPORT_SYMBOL(tcp_hashinfo); |
| 98 | |
| 99 | static __u32 tcp_v4_init_sequence(const struct sk_buff *skb) |
| 100 | { |
| 101 | return secure_tcp_sequence_number(ip_hdr(skb)->daddr, |
| 102 | ip_hdr(skb)->saddr, |
| 103 | tcp_hdr(skb)->dest, |
| 104 | tcp_hdr(skb)->source); |
| 105 | } |
| 106 | |
| 107 | int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp) |
| 108 | { |
| 109 | const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw); |
| 110 | struct tcp_sock *tp = tcp_sk(sk); |
| 111 | |
| 112 | /* With PAWS, it is safe from the viewpoint |
| 113 | of data integrity. Even without PAWS it is safe provided sequence |
| 114 | spaces do not overlap i.e. at data rates <= 80Mbit/sec. |
| 115 | |
| 116 | Actually, the idea is close to VJ's one, only timestamp cache is |
| 117 | held not per host, but per port pair and TW bucket is used as state |
| 118 | holder. |
| 119 | |
| 120 | If TW bucket has been already destroyed we fall back to VJ's scheme |
| 121 | and use initial timestamp retrieved from peer table. |
| 122 | */ |
| 123 | if (tcptw->tw_ts_recent_stamp && |
| 124 | (!twp || (sysctl_tcp_tw_reuse && |
| 125 | get_seconds() - tcptw->tw_ts_recent_stamp > 1))) { |
| 126 | tp->write_seq = tcptw->tw_snd_nxt + 65535 + 2; |
| 127 | if (tp->write_seq == 0) |
| 128 | tp->write_seq = 1; |
| 129 | tp->rx_opt.ts_recent = tcptw->tw_ts_recent; |
| 130 | tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp; |
| 131 | sock_hold(sktw); |
| 132 | return 1; |
| 133 | } |
| 134 | |
| 135 | return 0; |
| 136 | } |
| 137 | EXPORT_SYMBOL_GPL(tcp_twsk_unique); |
| 138 | |
| 139 | /* This will initiate an outgoing connection. */ |
| 140 | int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) |
| 141 | { |
| 142 | struct sockaddr_in *usin = (struct sockaddr_in *)uaddr; |
| 143 | struct inet_sock *inet = inet_sk(sk); |
| 144 | struct tcp_sock *tp = tcp_sk(sk); |
| 145 | __be16 orig_sport, orig_dport; |
| 146 | __be32 daddr, nexthop; |
| 147 | struct flowi4 *fl4; |
| 148 | struct rtable *rt; |
| 149 | int err; |
| 150 | struct ip_options_rcu *inet_opt; |
| 151 | |
| 152 | if (addr_len < sizeof(struct sockaddr_in)) |
| 153 | return -EINVAL; |
| 154 | |
| 155 | if (usin->sin_family != AF_INET) |
| 156 | return -EAFNOSUPPORT; |
| 157 | |
| 158 | nexthop = daddr = usin->sin_addr.s_addr; |
| 159 | inet_opt = rcu_dereference_protected(inet->inet_opt, |
| 160 | lockdep_sock_is_held(sk)); |
| 161 | if (inet_opt && inet_opt->opt.srr) { |
| 162 | if (!daddr) |
| 163 | return -EINVAL; |
| 164 | nexthop = inet_opt->opt.faddr; |
| 165 | } |
| 166 | |
| 167 | orig_sport = inet->inet_sport; |
| 168 | orig_dport = usin->sin_port; |
| 169 | fl4 = &inet->cork.fl.u.ip4; |
| 170 | rt = ip_route_connect(fl4, nexthop, inet->inet_saddr, |
| 171 | RT_CONN_FLAGS(sk), sk->sk_bound_dev_if, |
| 172 | IPPROTO_TCP, |
| 173 | orig_sport, orig_dport, sk); |
| 174 | if (IS_ERR(rt)) { |
| 175 | err = PTR_ERR(rt); |
| 176 | if (err == -ENETUNREACH) |
| 177 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); |
| 178 | return err; |
| 179 | } |
| 180 | |
| 181 | if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) { |
| 182 | ip_rt_put(rt); |
| 183 | return -ENETUNREACH; |
| 184 | } |
| 185 | |
| 186 | if (!inet_opt || !inet_opt->opt.srr) |
| 187 | daddr = fl4->daddr; |
| 188 | |
| 189 | if (!inet->inet_saddr) |
| 190 | inet->inet_saddr = fl4->saddr; |
| 191 | sk_rcv_saddr_set(sk, inet->inet_saddr); |
| 192 | |
| 193 | if (tp->rx_opt.ts_recent_stamp && inet->inet_daddr != daddr) { |
| 194 | /* Reset inherited state */ |
| 195 | tp->rx_opt.ts_recent = 0; |
| 196 | tp->rx_opt.ts_recent_stamp = 0; |
| 197 | if (likely(!tp->repair)) |
| 198 | tp->write_seq = 0; |
| 199 | } |
| 200 | |
| 201 | if (tcp_death_row.sysctl_tw_recycle && |
| 202 | !tp->rx_opt.ts_recent_stamp && fl4->daddr == daddr) |
| 203 | tcp_fetch_timewait_stamp(sk, &rt->dst); |
| 204 | |
| 205 | inet->inet_dport = usin->sin_port; |
| 206 | sk_daddr_set(sk, daddr); |
| 207 | |
| 208 | inet_csk(sk)->icsk_ext_hdr_len = 0; |
| 209 | if (inet_opt) |
| 210 | inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen; |
| 211 | |
| 212 | tp->rx_opt.mss_clamp = TCP_MSS_DEFAULT; |
| 213 | |
| 214 | /* Socket identity is still unknown (sport may be zero). |
| 215 | * However we set state to SYN-SENT and not releasing socket |
| 216 | * lock select source port, enter ourselves into the hash tables and |
| 217 | * complete initialization after this. |
| 218 | */ |
| 219 | tcp_set_state(sk, TCP_SYN_SENT); |
| 220 | err = inet_hash_connect(&tcp_death_row, sk); |
| 221 | if (err) |
| 222 | goto failure; |
| 223 | |
| 224 | sk_set_txhash(sk); |
| 225 | |
| 226 | rt = ip_route_newports(fl4, rt, orig_sport, orig_dport, |
| 227 | inet->inet_sport, inet->inet_dport, sk); |
| 228 | if (IS_ERR(rt)) { |
| 229 | err = PTR_ERR(rt); |
| 230 | rt = NULL; |
| 231 | goto failure; |
| 232 | } |
| 233 | /* OK, now commit destination to socket. */ |
| 234 | sk->sk_gso_type = SKB_GSO_TCPV4; |
| 235 | sk_setup_caps(sk, &rt->dst); |
| 236 | |
| 237 | if (!tp->write_seq && likely(!tp->repair)) |
| 238 | tp->write_seq = secure_tcp_sequence_number(inet->inet_saddr, |
| 239 | inet->inet_daddr, |
| 240 | inet->inet_sport, |
| 241 | usin->sin_port); |
| 242 | |
| 243 | inet->inet_id = tp->write_seq ^ jiffies; |
| 244 | |
| 245 | err = tcp_connect(sk); |
| 246 | |
| 247 | rt = NULL; |
| 248 | if (err) |
| 249 | goto failure; |
| 250 | |
| 251 | return 0; |
| 252 | |
| 253 | failure: |
| 254 | /* |
| 255 | * This unhashes the socket and releases the local port, |
| 256 | * if necessary. |
| 257 | */ |
| 258 | tcp_set_state(sk, TCP_CLOSE); |
| 259 | ip_rt_put(rt); |
| 260 | sk->sk_route_caps = 0; |
| 261 | inet->inet_dport = 0; |
| 262 | return err; |
| 263 | } |
| 264 | EXPORT_SYMBOL(tcp_v4_connect); |
| 265 | |
| 266 | /* |
| 267 | * This routine reacts to ICMP_FRAG_NEEDED mtu indications as defined in RFC1191. |
| 268 | * It can be called through tcp_release_cb() if socket was owned by user |
| 269 | * at the time tcp_v4_err() was called to handle ICMP message. |
| 270 | */ |
| 271 | void tcp_v4_mtu_reduced(struct sock *sk) |
| 272 | { |
| 273 | struct dst_entry *dst; |
| 274 | struct inet_sock *inet = inet_sk(sk); |
| 275 | u32 mtu = tcp_sk(sk)->mtu_info; |
| 276 | |
| 277 | dst = inet_csk_update_pmtu(sk, mtu); |
| 278 | if (!dst) |
| 279 | return; |
| 280 | |
| 281 | /* Something is about to be wrong... Remember soft error |
| 282 | * for the case, if this connection will not able to recover. |
| 283 | */ |
| 284 | if (mtu < dst_mtu(dst) && ip_dont_fragment(sk, dst)) |
| 285 | sk->sk_err_soft = EMSGSIZE; |
| 286 | |
| 287 | mtu = dst_mtu(dst); |
| 288 | |
| 289 | if (inet->pmtudisc != IP_PMTUDISC_DONT && |
| 290 | ip_sk_accept_pmtu(sk) && |
| 291 | inet_csk(sk)->icsk_pmtu_cookie > mtu) { |
| 292 | tcp_sync_mss(sk, mtu); |
| 293 | |
| 294 | /* Resend the TCP packet because it's |
| 295 | * clear that the old packet has been |
| 296 | * dropped. This is the new "fast" path mtu |
| 297 | * discovery. |
| 298 | */ |
| 299 | tcp_simple_retransmit(sk); |
| 300 | } /* else let the usual retransmit timer handle it */ |
| 301 | } |
| 302 | EXPORT_SYMBOL(tcp_v4_mtu_reduced); |
| 303 | |
| 304 | static void do_redirect(struct sk_buff *skb, struct sock *sk) |
| 305 | { |
| 306 | struct dst_entry *dst = __sk_dst_check(sk, 0); |
| 307 | |
| 308 | if (dst) |
| 309 | dst->ops->redirect(dst, sk, skb); |
| 310 | } |
| 311 | |
| 312 | |
| 313 | /* handle ICMP messages on TCP_NEW_SYN_RECV request sockets */ |
| 314 | void tcp_req_err(struct sock *sk, u32 seq, bool abort) |
| 315 | { |
| 316 | struct request_sock *req = inet_reqsk(sk); |
| 317 | struct net *net = sock_net(sk); |
| 318 | |
| 319 | /* ICMPs are not backlogged, hence we cannot get |
| 320 | * an established socket here. |
| 321 | */ |
| 322 | if (seq != tcp_rsk(req)->snt_isn) { |
| 323 | __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS); |
| 324 | } else if (abort) { |
| 325 | /* |
| 326 | * Still in SYN_RECV, just remove it silently. |
| 327 | * There is no good way to pass the error to the newly |
| 328 | * created socket, and POSIX does not want network |
| 329 | * errors returned from accept(). |
| 330 | */ |
| 331 | inet_csk_reqsk_queue_drop(req->rsk_listener, req); |
| 332 | tcp_listendrop(req->rsk_listener); |
| 333 | } |
| 334 | reqsk_put(req); |
| 335 | } |
| 336 | EXPORT_SYMBOL(tcp_req_err); |
| 337 | |
| 338 | /* |
| 339 | * This routine is called by the ICMP module when it gets some |
| 340 | * sort of error condition. If err < 0 then the socket should |
| 341 | * be closed and the error returned to the user. If err > 0 |
| 342 | * it's just the icmp type << 8 | icmp code. After adjustment |
| 343 | * header points to the first 8 bytes of the tcp header. We need |
| 344 | * to find the appropriate port. |
| 345 | * |
| 346 | * The locking strategy used here is very "optimistic". When |
| 347 | * someone else accesses the socket the ICMP is just dropped |
| 348 | * and for some paths there is no check at all. |
| 349 | * A more general error queue to queue errors for later handling |
| 350 | * is probably better. |
| 351 | * |
| 352 | */ |
| 353 | |
| 354 | void tcp_v4_err(struct sk_buff *icmp_skb, u32 info) |
| 355 | { |
| 356 | const struct iphdr *iph = (const struct iphdr *)icmp_skb->data; |
| 357 | struct tcphdr *th = (struct tcphdr *)(icmp_skb->data + (iph->ihl << 2)); |
| 358 | struct inet_connection_sock *icsk; |
| 359 | struct tcp_sock *tp; |
| 360 | struct inet_sock *inet; |
| 361 | const int type = icmp_hdr(icmp_skb)->type; |
| 362 | const int code = icmp_hdr(icmp_skb)->code; |
| 363 | struct sock *sk; |
| 364 | struct sk_buff *skb; |
| 365 | struct request_sock *fastopen; |
| 366 | __u32 seq, snd_una; |
| 367 | __u32 remaining; |
| 368 | int err; |
| 369 | struct net *net = dev_net(icmp_skb->dev); |
| 370 | |
| 371 | sk = __inet_lookup_established(net, &tcp_hashinfo, iph->daddr, |
| 372 | th->dest, iph->saddr, ntohs(th->source), |
| 373 | inet_iif(icmp_skb)); |
| 374 | if (!sk) { |
| 375 | __ICMP_INC_STATS(net, ICMP_MIB_INERRORS); |
| 376 | return; |
| 377 | } |
| 378 | if (sk->sk_state == TCP_TIME_WAIT) { |
| 379 | inet_twsk_put(inet_twsk(sk)); |
| 380 | return; |
| 381 | } |
| 382 | seq = ntohl(th->seq); |
| 383 | if (sk->sk_state == TCP_NEW_SYN_RECV) |
| 384 | return tcp_req_err(sk, seq, |
| 385 | type == ICMP_PARAMETERPROB || |
| 386 | type == ICMP_TIME_EXCEEDED || |
| 387 | (type == ICMP_DEST_UNREACH && |
| 388 | (code == ICMP_NET_UNREACH || |
| 389 | code == ICMP_HOST_UNREACH))); |
| 390 | |
| 391 | bh_lock_sock(sk); |
| 392 | /* If too many ICMPs get dropped on busy |
| 393 | * servers this needs to be solved differently. |
| 394 | * We do take care of PMTU discovery (RFC1191) special case : |
| 395 | * we can receive locally generated ICMP messages while socket is held. |
| 396 | */ |
| 397 | if (sock_owned_by_user(sk)) { |
| 398 | if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED)) |
| 399 | __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS); |
| 400 | } |
| 401 | if (sk->sk_state == TCP_CLOSE) |
| 402 | goto out; |
| 403 | |
| 404 | if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) { |
| 405 | __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP); |
| 406 | goto out; |
| 407 | } |
| 408 | |
| 409 | icsk = inet_csk(sk); |
| 410 | tp = tcp_sk(sk); |
| 411 | /* XXX (TFO) - tp->snd_una should be ISN (tcp_create_openreq_child() */ |
| 412 | fastopen = tp->fastopen_rsk; |
| 413 | snd_una = fastopen ? tcp_rsk(fastopen)->snt_isn : tp->snd_una; |
| 414 | if (sk->sk_state != TCP_LISTEN && |
| 415 | !between(seq, snd_una, tp->snd_nxt)) { |
| 416 | __NET_INC_STATS(net, LINUX_MIB_OUTOFWINDOWICMPS); |
| 417 | goto out; |
| 418 | } |
| 419 | |
| 420 | switch (type) { |
| 421 | case ICMP_REDIRECT: |
| 422 | do_redirect(icmp_skb, sk); |
| 423 | goto out; |
| 424 | case ICMP_SOURCE_QUENCH: |
| 425 | /* Just silently ignore these. */ |
| 426 | goto out; |
| 427 | case ICMP_PARAMETERPROB: |
| 428 | err = EPROTO; |
| 429 | break; |
| 430 | case ICMP_DEST_UNREACH: |
| 431 | if (code > NR_ICMP_UNREACH) |
| 432 | goto out; |
| 433 | |
| 434 | if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */ |
| 435 | /* We are not interested in TCP_LISTEN and open_requests |
| 436 | * (SYN-ACKs send out by Linux are always <576bytes so |
| 437 | * they should go through unfragmented). |
| 438 | */ |
| 439 | if (sk->sk_state == TCP_LISTEN) |
| 440 | goto out; |
| 441 | |
| 442 | tp->mtu_info = info; |
| 443 | if (!sock_owned_by_user(sk)) { |
| 444 | tcp_v4_mtu_reduced(sk); |
| 445 | } else { |
| 446 | if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, &tp->tsq_flags)) |
| 447 | sock_hold(sk); |
| 448 | } |
| 449 | goto out; |
| 450 | } |
| 451 | |
| 452 | err = icmp_err_convert[code].errno; |
| 453 | /* check if icmp_skb allows revert of backoff |
| 454 | * (see draft-zimmermann-tcp-lcd) */ |
| 455 | if (code != ICMP_NET_UNREACH && code != ICMP_HOST_UNREACH) |
| 456 | break; |
| 457 | if (seq != tp->snd_una || !icsk->icsk_retransmits || |
| 458 | !icsk->icsk_backoff || fastopen) |
| 459 | break; |
| 460 | |
| 461 | if (sock_owned_by_user(sk)) |
| 462 | break; |
| 463 | |
| 464 | icsk->icsk_backoff--; |
| 465 | icsk->icsk_rto = tp->srtt_us ? __tcp_set_rto(tp) : |
| 466 | TCP_TIMEOUT_INIT; |
| 467 | icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX); |
| 468 | |
| 469 | skb = tcp_write_queue_head(sk); |
| 470 | BUG_ON(!skb); |
| 471 | |
| 472 | remaining = icsk->icsk_rto - |
| 473 | min(icsk->icsk_rto, |
| 474 | tcp_time_stamp - tcp_skb_timestamp(skb)); |
| 475 | |
| 476 | if (remaining) { |
| 477 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
| 478 | remaining, TCP_RTO_MAX); |
| 479 | } else { |
| 480 | /* RTO revert clocked out retransmission. |
| 481 | * Will retransmit now */ |
| 482 | tcp_retransmit_timer(sk); |
| 483 | } |
| 484 | |
| 485 | break; |
| 486 | case ICMP_TIME_EXCEEDED: |
| 487 | err = EHOSTUNREACH; |
| 488 | break; |
| 489 | default: |
| 490 | goto out; |
| 491 | } |
| 492 | |
| 493 | switch (sk->sk_state) { |
| 494 | case TCP_SYN_SENT: |
| 495 | case TCP_SYN_RECV: |
| 496 | /* Only in fast or simultaneous open. If a fast open socket is |
| 497 | * is already accepted it is treated as a connected one below. |
| 498 | */ |
| 499 | if (fastopen && !fastopen->sk) |
| 500 | break; |
| 501 | |
| 502 | if (!sock_owned_by_user(sk)) { |
| 503 | sk->sk_err = err; |
| 504 | |
| 505 | sk->sk_error_report(sk); |
| 506 | |
| 507 | tcp_done(sk); |
| 508 | } else { |
| 509 | sk->sk_err_soft = err; |
| 510 | } |
| 511 | goto out; |
| 512 | } |
| 513 | |
| 514 | /* If we've already connected we will keep trying |
| 515 | * until we time out, or the user gives up. |
| 516 | * |
| 517 | * rfc1122 4.2.3.9 allows to consider as hard errors |
| 518 | * only PROTO_UNREACH and PORT_UNREACH (well, FRAG_FAILED too, |
| 519 | * but it is obsoleted by pmtu discovery). |
| 520 | * |
| 521 | * Note, that in modern internet, where routing is unreliable |
| 522 | * and in each dark corner broken firewalls sit, sending random |
| 523 | * errors ordered by their masters even this two messages finally lose |
| 524 | * their original sense (even Linux sends invalid PORT_UNREACHs) |
| 525 | * |
| 526 | * Now we are in compliance with RFCs. |
| 527 | * --ANK (980905) |
| 528 | */ |
| 529 | |
| 530 | inet = inet_sk(sk); |
| 531 | if (!sock_owned_by_user(sk) && inet->recverr) { |
| 532 | sk->sk_err = err; |
| 533 | sk->sk_error_report(sk); |
| 534 | } else { /* Only an error on timeout */ |
| 535 | sk->sk_err_soft = err; |
| 536 | } |
| 537 | |
| 538 | out: |
| 539 | bh_unlock_sock(sk); |
| 540 | sock_put(sk); |
| 541 | } |
| 542 | |
| 543 | void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr) |
| 544 | { |
| 545 | struct tcphdr *th = tcp_hdr(skb); |
| 546 | |
| 547 | if (skb->ip_summed == CHECKSUM_PARTIAL) { |
| 548 | th->check = ~tcp_v4_check(skb->len, saddr, daddr, 0); |
| 549 | skb->csum_start = skb_transport_header(skb) - skb->head; |
| 550 | skb->csum_offset = offsetof(struct tcphdr, check); |
| 551 | } else { |
| 552 | th->check = tcp_v4_check(skb->len, saddr, daddr, |
| 553 | csum_partial(th, |
| 554 | th->doff << 2, |
| 555 | skb->csum)); |
| 556 | } |
| 557 | } |
| 558 | |
| 559 | /* This routine computes an IPv4 TCP checksum. */ |
| 560 | void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb) |
| 561 | { |
| 562 | const struct inet_sock *inet = inet_sk(sk); |
| 563 | |
| 564 | __tcp_v4_send_check(skb, inet->inet_saddr, inet->inet_daddr); |
| 565 | } |
| 566 | EXPORT_SYMBOL(tcp_v4_send_check); |
| 567 | |
| 568 | /* |
| 569 | * This routine will send an RST to the other tcp. |
| 570 | * |
| 571 | * Someone asks: why I NEVER use socket parameters (TOS, TTL etc.) |
| 572 | * for reset. |
| 573 | * Answer: if a packet caused RST, it is not for a socket |
| 574 | * existing in our system, if it is matched to a socket, |
| 575 | * it is just duplicate segment or bug in other side's TCP. |
| 576 | * So that we build reply only basing on parameters |
| 577 | * arrived with segment. |
| 578 | * Exception: precedence violation. We do not implement it in any case. |
| 579 | */ |
| 580 | |
| 581 | static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) |
| 582 | { |
| 583 | const struct tcphdr *th = tcp_hdr(skb); |
| 584 | struct { |
| 585 | struct tcphdr th; |
| 586 | #ifdef CONFIG_TCP_MD5SIG |
| 587 | __be32 opt[(TCPOLEN_MD5SIG_ALIGNED >> 2)]; |
| 588 | #endif |
| 589 | } rep; |
| 590 | struct ip_reply_arg arg; |
| 591 | #ifdef CONFIG_TCP_MD5SIG |
| 592 | struct tcp_md5sig_key *key = NULL; |
| 593 | const __u8 *hash_location = NULL; |
| 594 | unsigned char newhash[16]; |
| 595 | int genhash; |
| 596 | struct sock *sk1 = NULL; |
| 597 | #endif |
| 598 | struct net *net; |
| 599 | |
| 600 | /* Never send a reset in response to a reset. */ |
| 601 | if (th->rst) |
| 602 | return; |
| 603 | |
| 604 | /* If sk not NULL, it means we did a successful lookup and incoming |
| 605 | * route had to be correct. prequeue might have dropped our dst. |
| 606 | */ |
| 607 | if (!sk && skb_rtable(skb)->rt_type != RTN_LOCAL) |
| 608 | return; |
| 609 | |
| 610 | /* Swap the send and the receive. */ |
| 611 | memset(&rep, 0, sizeof(rep)); |
| 612 | rep.th.dest = th->source; |
| 613 | rep.th.source = th->dest; |
| 614 | rep.th.doff = sizeof(struct tcphdr) / 4; |
| 615 | rep.th.rst = 1; |
| 616 | |
| 617 | if (th->ack) { |
| 618 | rep.th.seq = th->ack_seq; |
| 619 | } else { |
| 620 | rep.th.ack = 1; |
| 621 | rep.th.ack_seq = htonl(ntohl(th->seq) + th->syn + th->fin + |
| 622 | skb->len - (th->doff << 2)); |
| 623 | } |
| 624 | |
| 625 | memset(&arg, 0, sizeof(arg)); |
| 626 | arg.iov[0].iov_base = (unsigned char *)&rep; |
| 627 | arg.iov[0].iov_len = sizeof(rep.th); |
| 628 | |
| 629 | net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); |
| 630 | #ifdef CONFIG_TCP_MD5SIG |
| 631 | rcu_read_lock(); |
| 632 | hash_location = tcp_parse_md5sig_option(th); |
| 633 | if (sk && sk_fullsock(sk)) { |
| 634 | key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *) |
| 635 | &ip_hdr(skb)->saddr, AF_INET); |
| 636 | } else if (hash_location) { |
| 637 | /* |
| 638 | * active side is lost. Try to find listening socket through |
| 639 | * source port, and then find md5 key through listening socket. |
| 640 | * we are not loose security here: |
| 641 | * Incoming packet is checked with md5 hash with finding key, |
| 642 | * no RST generated if md5 hash doesn't match. |
| 643 | */ |
| 644 | sk1 = __inet_lookup_listener(net, &tcp_hashinfo, NULL, 0, |
| 645 | ip_hdr(skb)->saddr, |
| 646 | th->source, ip_hdr(skb)->daddr, |
| 647 | ntohs(th->source), inet_iif(skb)); |
| 648 | /* don't send rst if it can't find key */ |
| 649 | if (!sk1) |
| 650 | goto out; |
| 651 | |
| 652 | key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *) |
| 653 | &ip_hdr(skb)->saddr, AF_INET); |
| 654 | if (!key) |
| 655 | goto out; |
| 656 | |
| 657 | |
| 658 | genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb); |
| 659 | if (genhash || memcmp(hash_location, newhash, 16) != 0) |
| 660 | goto out; |
| 661 | |
| 662 | } |
| 663 | |
| 664 | if (key) { |
| 665 | rep.opt[0] = htonl((TCPOPT_NOP << 24) | |
| 666 | (TCPOPT_NOP << 16) | |
| 667 | (TCPOPT_MD5SIG << 8) | |
| 668 | TCPOLEN_MD5SIG); |
| 669 | /* Update length and the length the header thinks exists */ |
| 670 | arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; |
| 671 | rep.th.doff = arg.iov[0].iov_len / 4; |
| 672 | |
| 673 | tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1], |
| 674 | key, ip_hdr(skb)->saddr, |
| 675 | ip_hdr(skb)->daddr, &rep.th); |
| 676 | } |
| 677 | #endif |
| 678 | arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, |
| 679 | ip_hdr(skb)->saddr, /* XXX */ |
| 680 | arg.iov[0].iov_len, IPPROTO_TCP, 0); |
| 681 | arg.csumoffset = offsetof(struct tcphdr, check) / 2; |
| 682 | arg.flags = (sk && inet_sk_transparent(sk)) ? IP_REPLY_ARG_NOSRCCHECK : 0; |
| 683 | |
| 684 | /* When socket is gone, all binding information is lost. |
| 685 | * routing might fail in this case. No choice here, if we choose to force |
| 686 | * input interface, we will misroute in case of asymmetric route. |
| 687 | */ |
| 688 | if (sk) |
| 689 | arg.bound_dev_if = sk->sk_bound_dev_if; |
| 690 | |
| 691 | BUILD_BUG_ON(offsetof(struct sock, sk_bound_dev_if) != |
| 692 | offsetof(struct inet_timewait_sock, tw_bound_dev_if)); |
| 693 | |
| 694 | arg.tos = ip_hdr(skb)->tos; |
| 695 | ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk), |
| 696 | skb, &TCP_SKB_CB(skb)->header.h4.opt, |
| 697 | ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, |
| 698 | &arg, arg.iov[0].iov_len); |
| 699 | |
| 700 | __TCP_INC_STATS(net, TCP_MIB_OUTSEGS); |
| 701 | __TCP_INC_STATS(net, TCP_MIB_OUTRSTS); |
| 702 | |
| 703 | #ifdef CONFIG_TCP_MD5SIG |
| 704 | out: |
| 705 | rcu_read_unlock(); |
| 706 | #endif |
| 707 | } |
| 708 | |
| 709 | /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states |
| 710 | outside socket context is ugly, certainly. What can I do? |
| 711 | */ |
| 712 | |
| 713 | static void tcp_v4_send_ack(struct net *net, |
| 714 | struct sk_buff *skb, u32 seq, u32 ack, |
| 715 | u32 win, u32 tsval, u32 tsecr, int oif, |
| 716 | struct tcp_md5sig_key *key, |
| 717 | int reply_flags, u8 tos) |
| 718 | { |
| 719 | const struct tcphdr *th = tcp_hdr(skb); |
| 720 | struct { |
| 721 | struct tcphdr th; |
| 722 | __be32 opt[(TCPOLEN_TSTAMP_ALIGNED >> 2) |
| 723 | #ifdef CONFIG_TCP_MD5SIG |
| 724 | + (TCPOLEN_MD5SIG_ALIGNED >> 2) |
| 725 | #endif |
| 726 | ]; |
| 727 | } rep; |
| 728 | struct ip_reply_arg arg; |
| 729 | |
| 730 | memset(&rep.th, 0, sizeof(struct tcphdr)); |
| 731 | memset(&arg, 0, sizeof(arg)); |
| 732 | |
| 733 | arg.iov[0].iov_base = (unsigned char *)&rep; |
| 734 | arg.iov[0].iov_len = sizeof(rep.th); |
| 735 | if (tsecr) { |
| 736 | rep.opt[0] = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | |
| 737 | (TCPOPT_TIMESTAMP << 8) | |
| 738 | TCPOLEN_TIMESTAMP); |
| 739 | rep.opt[1] = htonl(tsval); |
| 740 | rep.opt[2] = htonl(tsecr); |
| 741 | arg.iov[0].iov_len += TCPOLEN_TSTAMP_ALIGNED; |
| 742 | } |
| 743 | |
| 744 | /* Swap the send and the receive. */ |
| 745 | rep.th.dest = th->source; |
| 746 | rep.th.source = th->dest; |
| 747 | rep.th.doff = arg.iov[0].iov_len / 4; |
| 748 | rep.th.seq = htonl(seq); |
| 749 | rep.th.ack_seq = htonl(ack); |
| 750 | rep.th.ack = 1; |
| 751 | rep.th.window = htons(win); |
| 752 | |
| 753 | #ifdef CONFIG_TCP_MD5SIG |
| 754 | if (key) { |
| 755 | int offset = (tsecr) ? 3 : 0; |
| 756 | |
| 757 | rep.opt[offset++] = htonl((TCPOPT_NOP << 24) | |
| 758 | (TCPOPT_NOP << 16) | |
| 759 | (TCPOPT_MD5SIG << 8) | |
| 760 | TCPOLEN_MD5SIG); |
| 761 | arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; |
| 762 | rep.th.doff = arg.iov[0].iov_len/4; |
| 763 | |
| 764 | tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[offset], |
| 765 | key, ip_hdr(skb)->saddr, |
| 766 | ip_hdr(skb)->daddr, &rep.th); |
| 767 | } |
| 768 | #endif |
| 769 | arg.flags = reply_flags; |
| 770 | arg.csum = csum_tcpudp_nofold(ip_hdr(skb)->daddr, |
| 771 | ip_hdr(skb)->saddr, /* XXX */ |
| 772 | arg.iov[0].iov_len, IPPROTO_TCP, 0); |
| 773 | arg.csumoffset = offsetof(struct tcphdr, check) / 2; |
| 774 | if (oif) |
| 775 | arg.bound_dev_if = oif; |
| 776 | arg.tos = tos; |
| 777 | ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk), |
| 778 | skb, &TCP_SKB_CB(skb)->header.h4.opt, |
| 779 | ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, |
| 780 | &arg, arg.iov[0].iov_len); |
| 781 | |
| 782 | __TCP_INC_STATS(net, TCP_MIB_OUTSEGS); |
| 783 | } |
| 784 | |
| 785 | static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) |
| 786 | { |
| 787 | struct inet_timewait_sock *tw = inet_twsk(sk); |
| 788 | struct tcp_timewait_sock *tcptw = tcp_twsk(sk); |
| 789 | |
| 790 | tcp_v4_send_ack(sock_net(sk), skb, |
| 791 | tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, |
| 792 | tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, |
| 793 | tcp_time_stamp + tcptw->tw_ts_offset, |
| 794 | tcptw->tw_ts_recent, |
| 795 | tw->tw_bound_dev_if, |
| 796 | tcp_twsk_md5_key(tcptw), |
| 797 | tw->tw_transparent ? IP_REPLY_ARG_NOSRCCHECK : 0, |
| 798 | tw->tw_tos |
| 799 | ); |
| 800 | |
| 801 | inet_twsk_put(tw); |
| 802 | } |
| 803 | |
| 804 | static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, |
| 805 | struct request_sock *req) |
| 806 | { |
| 807 | /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV |
| 808 | * sk->sk_state == TCP_SYN_RECV -> for Fast Open. |
| 809 | */ |
| 810 | u32 seq = (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 : |
| 811 | tcp_sk(sk)->snd_nxt; |
| 812 | |
| 813 | tcp_v4_send_ack(sock_net(sk), skb, seq, |
| 814 | tcp_rsk(req)->rcv_nxt, req->rsk_rcv_wnd, |
| 815 | tcp_time_stamp, |
| 816 | req->ts_recent, |
| 817 | 0, |
| 818 | tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr, |
| 819 | AF_INET), |
| 820 | inet_rsk(req)->no_srccheck ? IP_REPLY_ARG_NOSRCCHECK : 0, |
| 821 | ip_hdr(skb)->tos); |
| 822 | } |
| 823 | |
| 824 | /* |
| 825 | * Send a SYN-ACK after having received a SYN. |
| 826 | * This still operates on a request_sock only, not on a big |
| 827 | * socket. |
| 828 | */ |
| 829 | static int tcp_v4_send_synack(const struct sock *sk, struct dst_entry *dst, |
| 830 | struct flowi *fl, |
| 831 | struct request_sock *req, |
| 832 | struct tcp_fastopen_cookie *foc, |
| 833 | enum tcp_synack_type synack_type) |
| 834 | { |
| 835 | const struct inet_request_sock *ireq = inet_rsk(req); |
| 836 | struct flowi4 fl4; |
| 837 | int err = -1; |
| 838 | struct sk_buff *skb; |
| 839 | |
| 840 | /* First, grab a route. */ |
| 841 | if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL) |
| 842 | return -1; |
| 843 | |
| 844 | skb = tcp_make_synack(sk, dst, req, foc, synack_type); |
| 845 | |
| 846 | if (skb) { |
| 847 | __tcp_v4_send_check(skb, ireq->ir_loc_addr, ireq->ir_rmt_addr); |
| 848 | |
| 849 | err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr, |
| 850 | ireq->ir_rmt_addr, |
| 851 | ireq->opt); |
| 852 | err = net_xmit_eval(err); |
| 853 | } |
| 854 | |
| 855 | return err; |
| 856 | } |
| 857 | |
| 858 | /* |
| 859 | * IPv4 request_sock destructor. |
| 860 | */ |
| 861 | static void tcp_v4_reqsk_destructor(struct request_sock *req) |
| 862 | { |
| 863 | kfree(inet_rsk(req)->opt); |
| 864 | } |
| 865 | |
| 866 | #ifdef CONFIG_TCP_MD5SIG |
| 867 | /* |
| 868 | * RFC2385 MD5 checksumming requires a mapping of |
| 869 | * IP address->MD5 Key. |
| 870 | * We need to maintain these in the sk structure. |
| 871 | */ |
| 872 | |
| 873 | /* Find the Key structure for an address. */ |
| 874 | struct tcp_md5sig_key *tcp_md5_do_lookup(const struct sock *sk, |
| 875 | const union tcp_md5_addr *addr, |
| 876 | int family) |
| 877 | { |
| 878 | const struct tcp_sock *tp = tcp_sk(sk); |
| 879 | struct tcp_md5sig_key *key; |
| 880 | unsigned int size = sizeof(struct in_addr); |
| 881 | const struct tcp_md5sig_info *md5sig; |
| 882 | |
| 883 | /* caller either holds rcu_read_lock() or socket lock */ |
| 884 | md5sig = rcu_dereference_check(tp->md5sig_info, |
| 885 | lockdep_sock_is_held(sk)); |
| 886 | if (!md5sig) |
| 887 | return NULL; |
| 888 | #if IS_ENABLED(CONFIG_IPV6) |
| 889 | if (family == AF_INET6) |
| 890 | size = sizeof(struct in6_addr); |
| 891 | #endif |
| 892 | hlist_for_each_entry_rcu(key, &md5sig->head, node) { |
| 893 | if (key->family != family) |
| 894 | continue; |
| 895 | if (!memcmp(&key->addr, addr, size)) |
| 896 | return key; |
| 897 | } |
| 898 | return NULL; |
| 899 | } |
| 900 | EXPORT_SYMBOL(tcp_md5_do_lookup); |
| 901 | |
| 902 | struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, |
| 903 | const struct sock *addr_sk) |
| 904 | { |
| 905 | const union tcp_md5_addr *addr; |
| 906 | |
| 907 | addr = (const union tcp_md5_addr *)&addr_sk->sk_daddr; |
| 908 | return tcp_md5_do_lookup(sk, addr, AF_INET); |
| 909 | } |
| 910 | EXPORT_SYMBOL(tcp_v4_md5_lookup); |
| 911 | |
| 912 | /* This can be called on a newly created socket, from other files */ |
| 913 | int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, |
| 914 | int family, const u8 *newkey, u8 newkeylen, gfp_t gfp) |
| 915 | { |
| 916 | /* Add Key to the list */ |
| 917 | struct tcp_md5sig_key *key; |
| 918 | struct tcp_sock *tp = tcp_sk(sk); |
| 919 | struct tcp_md5sig_info *md5sig; |
| 920 | |
| 921 | key = tcp_md5_do_lookup(sk, addr, family); |
| 922 | if (key) { |
| 923 | /* Pre-existing entry - just update that one. */ |
| 924 | memcpy(key->key, newkey, newkeylen); |
| 925 | key->keylen = newkeylen; |
| 926 | return 0; |
| 927 | } |
| 928 | |
| 929 | md5sig = rcu_dereference_protected(tp->md5sig_info, |
| 930 | lockdep_sock_is_held(sk)); |
| 931 | if (!md5sig) { |
| 932 | md5sig = kmalloc(sizeof(*md5sig), gfp); |
| 933 | if (!md5sig) |
| 934 | return -ENOMEM; |
| 935 | |
| 936 | sk_nocaps_add(sk, NETIF_F_GSO_MASK); |
| 937 | INIT_HLIST_HEAD(&md5sig->head); |
| 938 | rcu_assign_pointer(tp->md5sig_info, md5sig); |
| 939 | } |
| 940 | |
| 941 | key = sock_kmalloc(sk, sizeof(*key), gfp); |
| 942 | if (!key) |
| 943 | return -ENOMEM; |
| 944 | if (!tcp_alloc_md5sig_pool()) { |
| 945 | sock_kfree_s(sk, key, sizeof(*key)); |
| 946 | return -ENOMEM; |
| 947 | } |
| 948 | |
| 949 | memcpy(key->key, newkey, newkeylen); |
| 950 | key->keylen = newkeylen; |
| 951 | key->family = family; |
| 952 | memcpy(&key->addr, addr, |
| 953 | (family == AF_INET6) ? sizeof(struct in6_addr) : |
| 954 | sizeof(struct in_addr)); |
| 955 | hlist_add_head_rcu(&key->node, &md5sig->head); |
| 956 | return 0; |
| 957 | } |
| 958 | EXPORT_SYMBOL(tcp_md5_do_add); |
| 959 | |
| 960 | int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family) |
| 961 | { |
| 962 | struct tcp_md5sig_key *key; |
| 963 | |
| 964 | key = tcp_md5_do_lookup(sk, addr, family); |
| 965 | if (!key) |
| 966 | return -ENOENT; |
| 967 | hlist_del_rcu(&key->node); |
| 968 | atomic_sub(sizeof(*key), &sk->sk_omem_alloc); |
| 969 | kfree_rcu(key, rcu); |
| 970 | return 0; |
| 971 | } |
| 972 | EXPORT_SYMBOL(tcp_md5_do_del); |
| 973 | |
| 974 | static void tcp_clear_md5_list(struct sock *sk) |
| 975 | { |
| 976 | struct tcp_sock *tp = tcp_sk(sk); |
| 977 | struct tcp_md5sig_key *key; |
| 978 | struct hlist_node *n; |
| 979 | struct tcp_md5sig_info *md5sig; |
| 980 | |
| 981 | md5sig = rcu_dereference_protected(tp->md5sig_info, 1); |
| 982 | |
| 983 | hlist_for_each_entry_safe(key, n, &md5sig->head, node) { |
| 984 | hlist_del_rcu(&key->node); |
| 985 | atomic_sub(sizeof(*key), &sk->sk_omem_alloc); |
| 986 | kfree_rcu(key, rcu); |
| 987 | } |
| 988 | } |
| 989 | |
| 990 | static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval, |
| 991 | int optlen) |
| 992 | { |
| 993 | struct tcp_md5sig cmd; |
| 994 | struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr; |
| 995 | |
| 996 | if (optlen < sizeof(cmd)) |
| 997 | return -EINVAL; |
| 998 | |
| 999 | if (copy_from_user(&cmd, optval, sizeof(cmd))) |
| 1000 | return -EFAULT; |
| 1001 | |
| 1002 | if (sin->sin_family != AF_INET) |
| 1003 | return -EINVAL; |
| 1004 | |
| 1005 | if (!cmd.tcpm_keylen) |
| 1006 | return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr, |
| 1007 | AF_INET); |
| 1008 | |
| 1009 | if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN) |
| 1010 | return -EINVAL; |
| 1011 | |
| 1012 | return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr, |
| 1013 | AF_INET, cmd.tcpm_key, cmd.tcpm_keylen, |
| 1014 | GFP_KERNEL); |
| 1015 | } |
| 1016 | |
| 1017 | static int tcp_v4_md5_hash_pseudoheader(struct tcp_md5sig_pool *hp, |
| 1018 | __be32 daddr, __be32 saddr, int nbytes) |
| 1019 | { |
| 1020 | struct tcp4_pseudohdr *bp; |
| 1021 | struct scatterlist sg; |
| 1022 | |
| 1023 | bp = &hp->md5_blk.ip4; |
| 1024 | |
| 1025 | /* |
| 1026 | * 1. the TCP pseudo-header (in the order: source IP address, |
| 1027 | * destination IP address, zero-padded protocol number, and |
| 1028 | * segment length) |
| 1029 | */ |
| 1030 | bp->saddr = saddr; |
| 1031 | bp->daddr = daddr; |
| 1032 | bp->pad = 0; |
| 1033 | bp->protocol = IPPROTO_TCP; |
| 1034 | bp->len = cpu_to_be16(nbytes); |
| 1035 | |
| 1036 | sg_init_one(&sg, bp, sizeof(*bp)); |
| 1037 | ahash_request_set_crypt(hp->md5_req, &sg, NULL, sizeof(*bp)); |
| 1038 | return crypto_ahash_update(hp->md5_req); |
| 1039 | } |
| 1040 | |
| 1041 | static int tcp_v4_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, |
| 1042 | __be32 daddr, __be32 saddr, const struct tcphdr *th) |
| 1043 | { |
| 1044 | struct tcp_md5sig_pool *hp; |
| 1045 | struct ahash_request *req; |
| 1046 | |
| 1047 | hp = tcp_get_md5sig_pool(); |
| 1048 | if (!hp) |
| 1049 | goto clear_hash_noput; |
| 1050 | req = hp->md5_req; |
| 1051 | |
| 1052 | if (crypto_ahash_init(req)) |
| 1053 | goto clear_hash; |
| 1054 | if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, th->doff << 2)) |
| 1055 | goto clear_hash; |
| 1056 | if (tcp_md5_hash_header(hp, th)) |
| 1057 | goto clear_hash; |
| 1058 | if (tcp_md5_hash_key(hp, key)) |
| 1059 | goto clear_hash; |
| 1060 | ahash_request_set_crypt(req, NULL, md5_hash, 0); |
| 1061 | if (crypto_ahash_final(req)) |
| 1062 | goto clear_hash; |
| 1063 | |
| 1064 | tcp_put_md5sig_pool(); |
| 1065 | return 0; |
| 1066 | |
| 1067 | clear_hash: |
| 1068 | tcp_put_md5sig_pool(); |
| 1069 | clear_hash_noput: |
| 1070 | memset(md5_hash, 0, 16); |
| 1071 | return 1; |
| 1072 | } |
| 1073 | |
| 1074 | int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, |
| 1075 | const struct sock *sk, |
| 1076 | const struct sk_buff *skb) |
| 1077 | { |
| 1078 | struct tcp_md5sig_pool *hp; |
| 1079 | struct ahash_request *req; |
| 1080 | const struct tcphdr *th = tcp_hdr(skb); |
| 1081 | __be32 saddr, daddr; |
| 1082 | |
| 1083 | if (sk) { /* valid for establish/request sockets */ |
| 1084 | saddr = sk->sk_rcv_saddr; |
| 1085 | daddr = sk->sk_daddr; |
| 1086 | } else { |
| 1087 | const struct iphdr *iph = ip_hdr(skb); |
| 1088 | saddr = iph->saddr; |
| 1089 | daddr = iph->daddr; |
| 1090 | } |
| 1091 | |
| 1092 | hp = tcp_get_md5sig_pool(); |
| 1093 | if (!hp) |
| 1094 | goto clear_hash_noput; |
| 1095 | req = hp->md5_req; |
| 1096 | |
| 1097 | if (crypto_ahash_init(req)) |
| 1098 | goto clear_hash; |
| 1099 | |
| 1100 | if (tcp_v4_md5_hash_pseudoheader(hp, daddr, saddr, skb->len)) |
| 1101 | goto clear_hash; |
| 1102 | if (tcp_md5_hash_header(hp, th)) |
| 1103 | goto clear_hash; |
| 1104 | if (tcp_md5_hash_skb_data(hp, skb, th->doff << 2)) |
| 1105 | goto clear_hash; |
| 1106 | if (tcp_md5_hash_key(hp, key)) |
| 1107 | goto clear_hash; |
| 1108 | ahash_request_set_crypt(req, NULL, md5_hash, 0); |
| 1109 | if (crypto_ahash_final(req)) |
| 1110 | goto clear_hash; |
| 1111 | |
| 1112 | tcp_put_md5sig_pool(); |
| 1113 | return 0; |
| 1114 | |
| 1115 | clear_hash: |
| 1116 | tcp_put_md5sig_pool(); |
| 1117 | clear_hash_noput: |
| 1118 | memset(md5_hash, 0, 16); |
| 1119 | return 1; |
| 1120 | } |
| 1121 | EXPORT_SYMBOL(tcp_v4_md5_hash_skb); |
| 1122 | |
| 1123 | #endif |
| 1124 | |
| 1125 | /* Called with rcu_read_lock() */ |
| 1126 | static bool tcp_v4_inbound_md5_hash(const struct sock *sk, |
| 1127 | const struct sk_buff *skb) |
| 1128 | { |
| 1129 | #ifdef CONFIG_TCP_MD5SIG |
| 1130 | /* |
| 1131 | * This gets called for each TCP segment that arrives |
| 1132 | * so we want to be efficient. |
| 1133 | * We have 3 drop cases: |
| 1134 | * o No MD5 hash and one expected. |
| 1135 | * o MD5 hash and we're not expecting one. |
| 1136 | * o MD5 hash and its wrong. |
| 1137 | */ |
| 1138 | const __u8 *hash_location = NULL; |
| 1139 | struct tcp_md5sig_key *hash_expected; |
| 1140 | const struct iphdr *iph = ip_hdr(skb); |
| 1141 | const struct tcphdr *th = tcp_hdr(skb); |
| 1142 | int genhash; |
| 1143 | unsigned char newhash[16]; |
| 1144 | |
| 1145 | hash_expected = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&iph->saddr, |
| 1146 | AF_INET); |
| 1147 | hash_location = tcp_parse_md5sig_option(th); |
| 1148 | |
| 1149 | /* We've parsed the options - do we have a hash? */ |
| 1150 | if (!hash_expected && !hash_location) |
| 1151 | return false; |
| 1152 | |
| 1153 | if (hash_expected && !hash_location) { |
| 1154 | __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND); |
| 1155 | return true; |
| 1156 | } |
| 1157 | |
| 1158 | if (!hash_expected && hash_location) { |
| 1159 | __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED); |
| 1160 | return true; |
| 1161 | } |
| 1162 | |
| 1163 | /* Okay, so this is hash_expected and hash_location - |
| 1164 | * so we need to calculate the checksum. |
| 1165 | */ |
| 1166 | genhash = tcp_v4_md5_hash_skb(newhash, |
| 1167 | hash_expected, |
| 1168 | NULL, skb); |
| 1169 | |
| 1170 | if (genhash || memcmp(hash_location, newhash, 16) != 0) { |
| 1171 | net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s\n", |
| 1172 | &iph->saddr, ntohs(th->source), |
| 1173 | &iph->daddr, ntohs(th->dest), |
| 1174 | genhash ? " tcp_v4_calc_md5_hash failed" |
| 1175 | : ""); |
| 1176 | return true; |
| 1177 | } |
| 1178 | return false; |
| 1179 | #endif |
| 1180 | return false; |
| 1181 | } |
| 1182 | |
| 1183 | static void tcp_v4_init_req(struct request_sock *req, |
| 1184 | const struct sock *sk_listener, |
| 1185 | struct sk_buff *skb) |
| 1186 | { |
| 1187 | struct inet_request_sock *ireq = inet_rsk(req); |
| 1188 | |
| 1189 | sk_rcv_saddr_set(req_to_sk(req), ip_hdr(skb)->daddr); |
| 1190 | sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr); |
| 1191 | ireq->no_srccheck = inet_sk(sk_listener)->transparent; |
| 1192 | ireq->opt = tcp_v4_save_options(skb); |
| 1193 | } |
| 1194 | |
| 1195 | static struct dst_entry *tcp_v4_route_req(const struct sock *sk, |
| 1196 | struct flowi *fl, |
| 1197 | const struct request_sock *req, |
| 1198 | bool *strict) |
| 1199 | { |
| 1200 | struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req); |
| 1201 | |
| 1202 | if (strict) { |
| 1203 | if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr) |
| 1204 | *strict = true; |
| 1205 | else |
| 1206 | *strict = false; |
| 1207 | } |
| 1208 | |
| 1209 | return dst; |
| 1210 | } |
| 1211 | |
| 1212 | struct request_sock_ops tcp_request_sock_ops __read_mostly = { |
| 1213 | .family = PF_INET, |
| 1214 | .obj_size = sizeof(struct tcp_request_sock), |
| 1215 | .rtx_syn_ack = tcp_rtx_synack, |
| 1216 | .send_ack = tcp_v4_reqsk_send_ack, |
| 1217 | .destructor = tcp_v4_reqsk_destructor, |
| 1218 | .send_reset = tcp_v4_send_reset, |
| 1219 | .syn_ack_timeout = tcp_syn_ack_timeout, |
| 1220 | }; |
| 1221 | |
| 1222 | static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = { |
| 1223 | .mss_clamp = TCP_MSS_DEFAULT, |
| 1224 | #ifdef CONFIG_TCP_MD5SIG |
| 1225 | .req_md5_lookup = tcp_v4_md5_lookup, |
| 1226 | .calc_md5_hash = tcp_v4_md5_hash_skb, |
| 1227 | #endif |
| 1228 | .init_req = tcp_v4_init_req, |
| 1229 | #ifdef CONFIG_SYN_COOKIES |
| 1230 | .cookie_init_seq = cookie_v4_init_sequence, |
| 1231 | #endif |
| 1232 | .route_req = tcp_v4_route_req, |
| 1233 | .init_seq = tcp_v4_init_sequence, |
| 1234 | .send_synack = tcp_v4_send_synack, |
| 1235 | }; |
| 1236 | |
| 1237 | int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb) |
| 1238 | { |
| 1239 | /* Never answer to SYNs send to broadcast or multicast */ |
| 1240 | if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) |
| 1241 | goto drop; |
| 1242 | |
| 1243 | return tcp_conn_request(&tcp_request_sock_ops, |
| 1244 | &tcp_request_sock_ipv4_ops, sk, skb); |
| 1245 | |
| 1246 | drop: |
| 1247 | tcp_listendrop(sk); |
| 1248 | return 0; |
| 1249 | } |
| 1250 | EXPORT_SYMBOL(tcp_v4_conn_request); |
| 1251 | |
| 1252 | |
| 1253 | /* |
| 1254 | * The three way handshake has completed - we got a valid synack - |
| 1255 | * now create the new socket. |
| 1256 | */ |
| 1257 | struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, |
| 1258 | struct request_sock *req, |
| 1259 | struct dst_entry *dst, |
| 1260 | struct request_sock *req_unhash, |
| 1261 | bool *own_req) |
| 1262 | { |
| 1263 | struct inet_request_sock *ireq; |
| 1264 | struct inet_sock *newinet; |
| 1265 | struct tcp_sock *newtp; |
| 1266 | struct sock *newsk; |
| 1267 | #ifdef CONFIG_TCP_MD5SIG |
| 1268 | struct tcp_md5sig_key *key; |
| 1269 | #endif |
| 1270 | struct ip_options_rcu *inet_opt; |
| 1271 | |
| 1272 | if (sk_acceptq_is_full(sk)) |
| 1273 | goto exit_overflow; |
| 1274 | |
| 1275 | newsk = tcp_create_openreq_child(sk, req, skb); |
| 1276 | if (!newsk) |
| 1277 | goto exit_nonewsk; |
| 1278 | |
| 1279 | newsk->sk_gso_type = SKB_GSO_TCPV4; |
| 1280 | inet_sk_rx_dst_set(newsk, skb); |
| 1281 | |
| 1282 | newtp = tcp_sk(newsk); |
| 1283 | newinet = inet_sk(newsk); |
| 1284 | ireq = inet_rsk(req); |
| 1285 | sk_daddr_set(newsk, ireq->ir_rmt_addr); |
| 1286 | sk_rcv_saddr_set(newsk, ireq->ir_loc_addr); |
| 1287 | newsk->sk_bound_dev_if = ireq->ir_iif; |
| 1288 | newinet->inet_saddr = ireq->ir_loc_addr; |
| 1289 | inet_opt = ireq->opt; |
| 1290 | rcu_assign_pointer(newinet->inet_opt, inet_opt); |
| 1291 | ireq->opt = NULL; |
| 1292 | newinet->mc_index = inet_iif(skb); |
| 1293 | newinet->mc_ttl = ip_hdr(skb)->ttl; |
| 1294 | newinet->rcv_tos = ip_hdr(skb)->tos; |
| 1295 | inet_csk(newsk)->icsk_ext_hdr_len = 0; |
| 1296 | if (inet_opt) |
| 1297 | inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; |
| 1298 | newinet->inet_id = newtp->write_seq ^ jiffies; |
| 1299 | |
| 1300 | if (!dst) { |
| 1301 | dst = inet_csk_route_child_sock(sk, newsk, req); |
| 1302 | if (!dst) |
| 1303 | goto put_and_exit; |
| 1304 | } else { |
| 1305 | /* syncookie case : see end of cookie_v4_check() */ |
| 1306 | } |
| 1307 | sk_setup_caps(newsk, dst); |
| 1308 | |
| 1309 | tcp_ca_openreq_child(newsk, dst); |
| 1310 | |
| 1311 | tcp_sync_mss(newsk, dst_mtu(dst)); |
| 1312 | newtp->advmss = dst_metric_advmss(dst); |
| 1313 | if (tcp_sk(sk)->rx_opt.user_mss && |
| 1314 | tcp_sk(sk)->rx_opt.user_mss < newtp->advmss) |
| 1315 | newtp->advmss = tcp_sk(sk)->rx_opt.user_mss; |
| 1316 | |
| 1317 | tcp_initialize_rcv_mss(newsk); |
| 1318 | |
| 1319 | #ifdef CONFIG_TCP_MD5SIG |
| 1320 | /* Copy over the MD5 key from the original socket */ |
| 1321 | key = tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&newinet->inet_daddr, |
| 1322 | AF_INET); |
| 1323 | if (key) { |
| 1324 | /* |
| 1325 | * We're using one, so create a matching key |
| 1326 | * on the newsk structure. If we fail to get |
| 1327 | * memory, then we end up not copying the key |
| 1328 | * across. Shucks. |
| 1329 | */ |
| 1330 | tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newinet->inet_daddr, |
| 1331 | AF_INET, key->key, key->keylen, GFP_ATOMIC); |
| 1332 | sk_nocaps_add(newsk, NETIF_F_GSO_MASK); |
| 1333 | } |
| 1334 | #endif |
| 1335 | |
| 1336 | if (__inet_inherit_port(sk, newsk) < 0) |
| 1337 | goto put_and_exit; |
| 1338 | *own_req = inet_ehash_nolisten(newsk, req_to_sk(req_unhash)); |
| 1339 | if (*own_req) |
| 1340 | tcp_move_syn(newtp, req); |
| 1341 | |
| 1342 | return newsk; |
| 1343 | |
| 1344 | exit_overflow: |
| 1345 | __NET_INC_STATS(sock_net(sk), LINUX_MIB_LISTENOVERFLOWS); |
| 1346 | exit_nonewsk: |
| 1347 | dst_release(dst); |
| 1348 | exit: |
| 1349 | tcp_listendrop(sk); |
| 1350 | return NULL; |
| 1351 | put_and_exit: |
| 1352 | inet_csk_prepare_forced_close(newsk); |
| 1353 | tcp_done(newsk); |
| 1354 | goto exit; |
| 1355 | } |
| 1356 | EXPORT_SYMBOL(tcp_v4_syn_recv_sock); |
| 1357 | |
| 1358 | static struct sock *tcp_v4_cookie_check(struct sock *sk, struct sk_buff *skb) |
| 1359 | { |
| 1360 | #ifdef CONFIG_SYN_COOKIES |
| 1361 | const struct tcphdr *th = tcp_hdr(skb); |
| 1362 | |
| 1363 | if (!th->syn) |
| 1364 | sk = cookie_v4_check(sk, skb); |
| 1365 | #endif |
| 1366 | return sk; |
| 1367 | } |
| 1368 | |
| 1369 | /* The socket must have it's spinlock held when we get |
| 1370 | * here, unless it is a TCP_LISTEN socket. |
| 1371 | * |
| 1372 | * We have a potential double-lock case here, so even when |
| 1373 | * doing backlog processing we use the BH locking scheme. |
| 1374 | * This is because we cannot sleep with the original spinlock |
| 1375 | * held. |
| 1376 | */ |
| 1377 | int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb) |
| 1378 | { |
| 1379 | struct sock *rsk; |
| 1380 | |
| 1381 | if (sk->sk_state == TCP_ESTABLISHED) { /* Fast path */ |
| 1382 | struct dst_entry *dst = sk->sk_rx_dst; |
| 1383 | |
| 1384 | sock_rps_save_rxhash(sk, skb); |
| 1385 | sk_mark_napi_id(sk, skb); |
| 1386 | if (dst) { |
| 1387 | if (inet_sk(sk)->rx_dst_ifindex != skb->skb_iif || |
| 1388 | !dst->ops->check(dst, 0)) { |
| 1389 | dst_release(dst); |
| 1390 | sk->sk_rx_dst = NULL; |
| 1391 | } |
| 1392 | } |
| 1393 | tcp_rcv_established(sk, skb, tcp_hdr(skb), skb->len); |
| 1394 | return 0; |
| 1395 | } |
| 1396 | |
| 1397 | if (tcp_checksum_complete(skb)) |
| 1398 | goto csum_err; |
| 1399 | |
| 1400 | if (sk->sk_state == TCP_LISTEN) { |
| 1401 | struct sock *nsk = tcp_v4_cookie_check(sk, skb); |
| 1402 | |
| 1403 | if (!nsk) |
| 1404 | goto discard; |
| 1405 | if (nsk != sk) { |
| 1406 | sock_rps_save_rxhash(nsk, skb); |
| 1407 | sk_mark_napi_id(nsk, skb); |
| 1408 | if (tcp_child_process(sk, nsk, skb)) { |
| 1409 | rsk = nsk; |
| 1410 | goto reset; |
| 1411 | } |
| 1412 | return 0; |
| 1413 | } |
| 1414 | } else |
| 1415 | sock_rps_save_rxhash(sk, skb); |
| 1416 | |
| 1417 | if (tcp_rcv_state_process(sk, skb)) { |
| 1418 | rsk = sk; |
| 1419 | goto reset; |
| 1420 | } |
| 1421 | return 0; |
| 1422 | |
| 1423 | reset: |
| 1424 | tcp_v4_send_reset(rsk, skb); |
| 1425 | discard: |
| 1426 | kfree_skb(skb); |
| 1427 | /* Be careful here. If this function gets more complicated and |
| 1428 | * gcc suffers from register pressure on the x86, sk (in %ebx) |
| 1429 | * might be destroyed here. This current version compiles correctly, |
| 1430 | * but you have been warned. |
| 1431 | */ |
| 1432 | return 0; |
| 1433 | |
| 1434 | csum_err: |
| 1435 | __TCP_INC_STATS(sock_net(sk), TCP_MIB_CSUMERRORS); |
| 1436 | __TCP_INC_STATS(sock_net(sk), TCP_MIB_INERRS); |
| 1437 | goto discard; |
| 1438 | } |
| 1439 | EXPORT_SYMBOL(tcp_v4_do_rcv); |
| 1440 | |
| 1441 | void tcp_v4_early_demux(struct sk_buff *skb) |
| 1442 | { |
| 1443 | const struct iphdr *iph; |
| 1444 | const struct tcphdr *th; |
| 1445 | struct sock *sk; |
| 1446 | |
| 1447 | if (skb->pkt_type != PACKET_HOST) |
| 1448 | return; |
| 1449 | |
| 1450 | if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct tcphdr))) |
| 1451 | return; |
| 1452 | |
| 1453 | iph = ip_hdr(skb); |
| 1454 | th = tcp_hdr(skb); |
| 1455 | |
| 1456 | if (th->doff < sizeof(struct tcphdr) / 4) |
| 1457 | return; |
| 1458 | |
| 1459 | sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo, |
| 1460 | iph->saddr, th->source, |
| 1461 | iph->daddr, ntohs(th->dest), |
| 1462 | skb->skb_iif); |
| 1463 | if (sk) { |
| 1464 | skb->sk = sk; |
| 1465 | skb->destructor = sock_edemux; |
| 1466 | if (sk_fullsock(sk)) { |
| 1467 | struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst); |
| 1468 | |
| 1469 | if (dst) |
| 1470 | dst = dst_check(dst, 0); |
| 1471 | if (dst && |
| 1472 | inet_sk(sk)->rx_dst_ifindex == skb->skb_iif) |
| 1473 | skb_dst_set_noref(skb, dst); |
| 1474 | } |
| 1475 | } |
| 1476 | } |
| 1477 | |
| 1478 | /* Packet is added to VJ-style prequeue for processing in process |
| 1479 | * context, if a reader task is waiting. Apparently, this exciting |
| 1480 | * idea (VJ's mail "Re: query about TCP header on tcp-ip" of 07 Sep 93) |
| 1481 | * failed somewhere. Latency? Burstiness? Well, at least now we will |
| 1482 | * see, why it failed. 8)8) --ANK |
| 1483 | * |
| 1484 | */ |
| 1485 | bool tcp_prequeue(struct sock *sk, struct sk_buff *skb) |
| 1486 | { |
| 1487 | struct tcp_sock *tp = tcp_sk(sk); |
| 1488 | |
| 1489 | if (sysctl_tcp_low_latency || !tp->ucopy.task) |
| 1490 | return false; |
| 1491 | |
| 1492 | if (skb->len <= tcp_hdrlen(skb) && |
| 1493 | skb_queue_len(&tp->ucopy.prequeue) == 0) |
| 1494 | return false; |
| 1495 | |
| 1496 | /* Before escaping RCU protected region, we need to take care of skb |
| 1497 | * dst. Prequeue is only enabled for established sockets. |
| 1498 | * For such sockets, we might need the skb dst only to set sk->sk_rx_dst |
| 1499 | * Instead of doing full sk_rx_dst validity here, let's perform |
| 1500 | * an optimistic check. |
| 1501 | */ |
| 1502 | if (likely(sk->sk_rx_dst)) |
| 1503 | skb_dst_drop(skb); |
| 1504 | else |
| 1505 | skb_dst_force_safe(skb); |
| 1506 | |
| 1507 | __skb_queue_tail(&tp->ucopy.prequeue, skb); |
| 1508 | tp->ucopy.memory += skb->truesize; |
| 1509 | if (skb_queue_len(&tp->ucopy.prequeue) >= 32 || |
| 1510 | tp->ucopy.memory + atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) { |
| 1511 | struct sk_buff *skb1; |
| 1512 | |
| 1513 | BUG_ON(sock_owned_by_user(sk)); |
| 1514 | __NET_ADD_STATS(sock_net(sk), LINUX_MIB_TCPPREQUEUEDROPPED, |
| 1515 | skb_queue_len(&tp->ucopy.prequeue)); |
| 1516 | |
| 1517 | while ((skb1 = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) |
| 1518 | sk_backlog_rcv(sk, skb1); |
| 1519 | |
| 1520 | tp->ucopy.memory = 0; |
| 1521 | } else if (skb_queue_len(&tp->ucopy.prequeue) == 1) { |
| 1522 | wake_up_interruptible_sync_poll(sk_sleep(sk), |
| 1523 | POLLIN | POLLRDNORM | POLLRDBAND); |
| 1524 | if (!inet_csk_ack_scheduled(sk)) |
| 1525 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_DACK, |
| 1526 | (3 * tcp_rto_min(sk)) / 4, |
| 1527 | TCP_RTO_MAX); |
| 1528 | } |
| 1529 | return true; |
| 1530 | } |
| 1531 | EXPORT_SYMBOL(tcp_prequeue); |
| 1532 | |
| 1533 | /* |
| 1534 | * From tcp_input.c |
| 1535 | */ |
| 1536 | |
| 1537 | int tcp_v4_rcv(struct sk_buff *skb) |
| 1538 | { |
| 1539 | struct net *net = dev_net(skb->dev); |
| 1540 | const struct iphdr *iph; |
| 1541 | const struct tcphdr *th; |
| 1542 | bool refcounted; |
| 1543 | struct sock *sk; |
| 1544 | int ret; |
| 1545 | |
| 1546 | if (skb->pkt_type != PACKET_HOST) |
| 1547 | goto discard_it; |
| 1548 | |
| 1549 | /* Count it even if it's bad */ |
| 1550 | __TCP_INC_STATS(net, TCP_MIB_INSEGS); |
| 1551 | |
| 1552 | if (!pskb_may_pull(skb, sizeof(struct tcphdr))) |
| 1553 | goto discard_it; |
| 1554 | |
| 1555 | th = tcp_hdr(skb); |
| 1556 | |
| 1557 | if (th->doff < sizeof(struct tcphdr) / 4) |
| 1558 | goto bad_packet; |
| 1559 | if (!pskb_may_pull(skb, th->doff * 4)) |
| 1560 | goto discard_it; |
| 1561 | |
| 1562 | /* An explanation is required here, I think. |
| 1563 | * Packet length and doff are validated by header prediction, |
| 1564 | * provided case of th->doff==0 is eliminated. |
| 1565 | * So, we defer the checks. */ |
| 1566 | |
| 1567 | if (skb_checksum_init(skb, IPPROTO_TCP, inet_compute_pseudo)) |
| 1568 | goto csum_error; |
| 1569 | |
| 1570 | th = tcp_hdr(skb); |
| 1571 | iph = ip_hdr(skb); |
| 1572 | /* This is tricky : We move IPCB at its correct location into TCP_SKB_CB() |
| 1573 | * barrier() makes sure compiler wont play fool^Waliasing games. |
| 1574 | */ |
| 1575 | memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb), |
| 1576 | sizeof(struct inet_skb_parm)); |
| 1577 | barrier(); |
| 1578 | |
| 1579 | TCP_SKB_CB(skb)->seq = ntohl(th->seq); |
| 1580 | TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin + |
| 1581 | skb->len - th->doff * 4); |
| 1582 | TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq); |
| 1583 | TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th); |
| 1584 | TCP_SKB_CB(skb)->tcp_tw_isn = 0; |
| 1585 | TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph); |
| 1586 | TCP_SKB_CB(skb)->sacked = 0; |
| 1587 | |
| 1588 | lookup: |
| 1589 | sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source, |
| 1590 | th->dest, &refcounted); |
| 1591 | if (!sk) |
| 1592 | goto no_tcp_socket; |
| 1593 | |
| 1594 | process: |
| 1595 | if (sk->sk_state == TCP_TIME_WAIT) |
| 1596 | goto do_time_wait; |
| 1597 | |
| 1598 | if (sk->sk_state == TCP_NEW_SYN_RECV) { |
| 1599 | struct request_sock *req = inet_reqsk(sk); |
| 1600 | struct sock *nsk; |
| 1601 | |
| 1602 | sk = req->rsk_listener; |
| 1603 | if (unlikely(tcp_v4_inbound_md5_hash(sk, skb))) { |
| 1604 | reqsk_put(req); |
| 1605 | goto discard_it; |
| 1606 | } |
| 1607 | if (unlikely(sk->sk_state != TCP_LISTEN)) { |
| 1608 | inet_csk_reqsk_queue_drop_and_put(sk, req); |
| 1609 | goto lookup; |
| 1610 | } |
| 1611 | /* We own a reference on the listener, increase it again |
| 1612 | * as we might lose it too soon. |
| 1613 | */ |
| 1614 | sock_hold(sk); |
| 1615 | refcounted = true; |
| 1616 | nsk = tcp_check_req(sk, skb, req, false); |
| 1617 | if (!nsk) { |
| 1618 | reqsk_put(req); |
| 1619 | goto discard_and_relse; |
| 1620 | } |
| 1621 | if (nsk == sk) { |
| 1622 | reqsk_put(req); |
| 1623 | } else if (tcp_child_process(sk, nsk, skb)) { |
| 1624 | tcp_v4_send_reset(nsk, skb); |
| 1625 | goto discard_and_relse; |
| 1626 | } else { |
| 1627 | sock_put(sk); |
| 1628 | return 0; |
| 1629 | } |
| 1630 | } |
| 1631 | if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) { |
| 1632 | __NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP); |
| 1633 | goto discard_and_relse; |
| 1634 | } |
| 1635 | |
| 1636 | if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) |
| 1637 | goto discard_and_relse; |
| 1638 | |
| 1639 | if (tcp_v4_inbound_md5_hash(sk, skb)) |
| 1640 | goto discard_and_relse; |
| 1641 | |
| 1642 | nf_reset(skb); |
| 1643 | |
| 1644 | if (sk_filter(sk, skb)) |
| 1645 | goto discard_and_relse; |
| 1646 | |
| 1647 | skb->dev = NULL; |
| 1648 | |
| 1649 | if (sk->sk_state == TCP_LISTEN) { |
| 1650 | ret = tcp_v4_do_rcv(sk, skb); |
| 1651 | goto put_and_return; |
| 1652 | } |
| 1653 | |
| 1654 | sk_incoming_cpu_update(sk); |
| 1655 | |
| 1656 | bh_lock_sock_nested(sk); |
| 1657 | tcp_segs_in(tcp_sk(sk), skb); |
| 1658 | ret = 0; |
| 1659 | if (!sock_owned_by_user(sk)) { |
| 1660 | if (!tcp_prequeue(sk, skb)) |
| 1661 | ret = tcp_v4_do_rcv(sk, skb); |
| 1662 | } else if (unlikely(sk_add_backlog(sk, skb, |
| 1663 | sk->sk_rcvbuf + sk->sk_sndbuf))) { |
| 1664 | bh_unlock_sock(sk); |
| 1665 | __NET_INC_STATS(net, LINUX_MIB_TCPBACKLOGDROP); |
| 1666 | goto discard_and_relse; |
| 1667 | } |
| 1668 | bh_unlock_sock(sk); |
| 1669 | |
| 1670 | put_and_return: |
| 1671 | if (refcounted) |
| 1672 | sock_put(sk); |
| 1673 | |
| 1674 | return ret; |
| 1675 | |
| 1676 | no_tcp_socket: |
| 1677 | if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) |
| 1678 | goto discard_it; |
| 1679 | |
| 1680 | if (tcp_checksum_complete(skb)) { |
| 1681 | csum_error: |
| 1682 | __TCP_INC_STATS(net, TCP_MIB_CSUMERRORS); |
| 1683 | bad_packet: |
| 1684 | __TCP_INC_STATS(net, TCP_MIB_INERRS); |
| 1685 | } else { |
| 1686 | tcp_v4_send_reset(NULL, skb); |
| 1687 | } |
| 1688 | |
| 1689 | discard_it: |
| 1690 | /* Discard frame. */ |
| 1691 | kfree_skb(skb); |
| 1692 | return 0; |
| 1693 | |
| 1694 | discard_and_relse: |
| 1695 | sk_drops_add(sk, skb); |
| 1696 | if (refcounted) |
| 1697 | sock_put(sk); |
| 1698 | goto discard_it; |
| 1699 | |
| 1700 | do_time_wait: |
| 1701 | if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { |
| 1702 | inet_twsk_put(inet_twsk(sk)); |
| 1703 | goto discard_it; |
| 1704 | } |
| 1705 | |
| 1706 | if (tcp_checksum_complete(skb)) { |
| 1707 | inet_twsk_put(inet_twsk(sk)); |
| 1708 | goto csum_error; |
| 1709 | } |
| 1710 | switch (tcp_timewait_state_process(inet_twsk(sk), skb, th)) { |
| 1711 | case TCP_TW_SYN: { |
| 1712 | struct sock *sk2 = inet_lookup_listener(dev_net(skb->dev), |
| 1713 | &tcp_hashinfo, skb, |
| 1714 | __tcp_hdrlen(th), |
| 1715 | iph->saddr, th->source, |
| 1716 | iph->daddr, th->dest, |
| 1717 | inet_iif(skb)); |
| 1718 | if (sk2) { |
| 1719 | inet_twsk_deschedule_put(inet_twsk(sk)); |
| 1720 | sk = sk2; |
| 1721 | refcounted = false; |
| 1722 | goto process; |
| 1723 | } |
| 1724 | /* Fall through to ACK */ |
| 1725 | } |
| 1726 | case TCP_TW_ACK: |
| 1727 | tcp_v4_timewait_ack(sk, skb); |
| 1728 | break; |
| 1729 | case TCP_TW_RST: |
| 1730 | tcp_v4_send_reset(sk, skb); |
| 1731 | inet_twsk_deschedule_put(inet_twsk(sk)); |
| 1732 | goto discard_it; |
| 1733 | case TCP_TW_SUCCESS:; |
| 1734 | } |
| 1735 | goto discard_it; |
| 1736 | } |
| 1737 | |
| 1738 | static struct timewait_sock_ops tcp_timewait_sock_ops = { |
| 1739 | .twsk_obj_size = sizeof(struct tcp_timewait_sock), |
| 1740 | .twsk_unique = tcp_twsk_unique, |
| 1741 | .twsk_destructor= tcp_twsk_destructor, |
| 1742 | }; |
| 1743 | |
| 1744 | void inet_sk_rx_dst_set(struct sock *sk, const struct sk_buff *skb) |
| 1745 | { |
| 1746 | struct dst_entry *dst = skb_dst(skb); |
| 1747 | |
| 1748 | if (dst && dst_hold_safe(dst)) { |
| 1749 | sk->sk_rx_dst = dst; |
| 1750 | inet_sk(sk)->rx_dst_ifindex = skb->skb_iif; |
| 1751 | } |
| 1752 | } |
| 1753 | EXPORT_SYMBOL(inet_sk_rx_dst_set); |
| 1754 | |
| 1755 | const struct inet_connection_sock_af_ops ipv4_specific = { |
| 1756 | .queue_xmit = ip_queue_xmit, |
| 1757 | .send_check = tcp_v4_send_check, |
| 1758 | .rebuild_header = inet_sk_rebuild_header, |
| 1759 | .sk_rx_dst_set = inet_sk_rx_dst_set, |
| 1760 | .conn_request = tcp_v4_conn_request, |
| 1761 | .syn_recv_sock = tcp_v4_syn_recv_sock, |
| 1762 | .net_header_len = sizeof(struct iphdr), |
| 1763 | .setsockopt = ip_setsockopt, |
| 1764 | .getsockopt = ip_getsockopt, |
| 1765 | .addr2sockaddr = inet_csk_addr2sockaddr, |
| 1766 | .sockaddr_len = sizeof(struct sockaddr_in), |
| 1767 | .bind_conflict = inet_csk_bind_conflict, |
| 1768 | #ifdef CONFIG_COMPAT |
| 1769 | .compat_setsockopt = compat_ip_setsockopt, |
| 1770 | .compat_getsockopt = compat_ip_getsockopt, |
| 1771 | #endif |
| 1772 | .mtu_reduced = tcp_v4_mtu_reduced, |
| 1773 | }; |
| 1774 | EXPORT_SYMBOL(ipv4_specific); |
| 1775 | |
| 1776 | #ifdef CONFIG_TCP_MD5SIG |
| 1777 | static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = { |
| 1778 | .md5_lookup = tcp_v4_md5_lookup, |
| 1779 | .calc_md5_hash = tcp_v4_md5_hash_skb, |
| 1780 | .md5_parse = tcp_v4_parse_md5_keys, |
| 1781 | }; |
| 1782 | #endif |
| 1783 | |
| 1784 | /* NOTE: A lot of things set to zero explicitly by call to |
| 1785 | * sk_alloc() so need not be done here. |
| 1786 | */ |
| 1787 | static int tcp_v4_init_sock(struct sock *sk) |
| 1788 | { |
| 1789 | struct inet_connection_sock *icsk = inet_csk(sk); |
| 1790 | |
| 1791 | tcp_init_sock(sk); |
| 1792 | |
| 1793 | icsk->icsk_af_ops = &ipv4_specific; |
| 1794 | |
| 1795 | #ifdef CONFIG_TCP_MD5SIG |
| 1796 | tcp_sk(sk)->af_specific = &tcp_sock_ipv4_specific; |
| 1797 | #endif |
| 1798 | |
| 1799 | return 0; |
| 1800 | } |
| 1801 | |
| 1802 | void tcp_v4_destroy_sock(struct sock *sk) |
| 1803 | { |
| 1804 | struct tcp_sock *tp = tcp_sk(sk); |
| 1805 | |
| 1806 | tcp_clear_xmit_timers(sk); |
| 1807 | |
| 1808 | tcp_cleanup_congestion_control(sk); |
| 1809 | |
| 1810 | /* Cleanup up the write buffer. */ |
| 1811 | tcp_write_queue_purge(sk); |
| 1812 | |
| 1813 | /* Cleans up our, hopefully empty, out_of_order_queue. */ |
| 1814 | __skb_queue_purge(&tp->out_of_order_queue); |
| 1815 | |
| 1816 | #ifdef CONFIG_TCP_MD5SIG |
| 1817 | /* Clean up the MD5 key list, if any */ |
| 1818 | if (tp->md5sig_info) { |
| 1819 | tcp_clear_md5_list(sk); |
| 1820 | kfree_rcu(tp->md5sig_info, rcu); |
| 1821 | tp->md5sig_info = NULL; |
| 1822 | } |
| 1823 | #endif |
| 1824 | |
| 1825 | /* Clean prequeue, it must be empty really */ |
| 1826 | __skb_queue_purge(&tp->ucopy.prequeue); |
| 1827 | |
| 1828 | /* Clean up a referenced TCP bind bucket. */ |
| 1829 | if (inet_csk(sk)->icsk_bind_hash) |
| 1830 | inet_put_port(sk); |
| 1831 | |
| 1832 | BUG_ON(tp->fastopen_rsk); |
| 1833 | |
| 1834 | /* If socket is aborted during connect operation */ |
| 1835 | tcp_free_fastopen_req(tp); |
| 1836 | tcp_saved_syn_free(tp); |
| 1837 | |
| 1838 | sk_sockets_allocated_dec(sk); |
| 1839 | |
| 1840 | if (mem_cgroup_sockets_enabled && sk->sk_memcg) |
| 1841 | sock_release_memcg(sk); |
| 1842 | } |
| 1843 | EXPORT_SYMBOL(tcp_v4_destroy_sock); |
| 1844 | |
| 1845 | #ifdef CONFIG_PROC_FS |
| 1846 | /* Proc filesystem TCP sock list dumping. */ |
| 1847 | |
| 1848 | /* |
| 1849 | * Get next listener socket follow cur. If cur is NULL, get first socket |
| 1850 | * starting from bucket given in st->bucket; when st->bucket is zero the |
| 1851 | * very first socket in the hash table is returned. |
| 1852 | */ |
| 1853 | static void *listening_get_next(struct seq_file *seq, void *cur) |
| 1854 | { |
| 1855 | struct tcp_iter_state *st = seq->private; |
| 1856 | struct net *net = seq_file_net(seq); |
| 1857 | struct inet_listen_hashbucket *ilb; |
| 1858 | struct inet_connection_sock *icsk; |
| 1859 | struct sock *sk = cur; |
| 1860 | |
| 1861 | if (!sk) { |
| 1862 | get_head: |
| 1863 | ilb = &tcp_hashinfo.listening_hash[st->bucket]; |
| 1864 | spin_lock_bh(&ilb->lock); |
| 1865 | sk = sk_head(&ilb->head); |
| 1866 | st->offset = 0; |
| 1867 | goto get_sk; |
| 1868 | } |
| 1869 | ilb = &tcp_hashinfo.listening_hash[st->bucket]; |
| 1870 | ++st->num; |
| 1871 | ++st->offset; |
| 1872 | |
| 1873 | sk = sk_next(sk); |
| 1874 | get_sk: |
| 1875 | sk_for_each_from(sk) { |
| 1876 | if (!net_eq(sock_net(sk), net)) |
| 1877 | continue; |
| 1878 | if (sk->sk_family == st->family) |
| 1879 | return sk; |
| 1880 | icsk = inet_csk(sk); |
| 1881 | } |
| 1882 | spin_unlock_bh(&ilb->lock); |
| 1883 | st->offset = 0; |
| 1884 | if (++st->bucket < INET_LHTABLE_SIZE) |
| 1885 | goto get_head; |
| 1886 | return NULL; |
| 1887 | } |
| 1888 | |
| 1889 | static void *listening_get_idx(struct seq_file *seq, loff_t *pos) |
| 1890 | { |
| 1891 | struct tcp_iter_state *st = seq->private; |
| 1892 | void *rc; |
| 1893 | |
| 1894 | st->bucket = 0; |
| 1895 | st->offset = 0; |
| 1896 | rc = listening_get_next(seq, NULL); |
| 1897 | |
| 1898 | while (rc && *pos) { |
| 1899 | rc = listening_get_next(seq, rc); |
| 1900 | --*pos; |
| 1901 | } |
| 1902 | return rc; |
| 1903 | } |
| 1904 | |
| 1905 | static inline bool empty_bucket(const struct tcp_iter_state *st) |
| 1906 | { |
| 1907 | return hlist_nulls_empty(&tcp_hashinfo.ehash[st->bucket].chain); |
| 1908 | } |
| 1909 | |
| 1910 | /* |
| 1911 | * Get first established socket starting from bucket given in st->bucket. |
| 1912 | * If st->bucket is zero, the very first socket in the hash is returned. |
| 1913 | */ |
| 1914 | static void *established_get_first(struct seq_file *seq) |
| 1915 | { |
| 1916 | struct tcp_iter_state *st = seq->private; |
| 1917 | struct net *net = seq_file_net(seq); |
| 1918 | void *rc = NULL; |
| 1919 | |
| 1920 | st->offset = 0; |
| 1921 | for (; st->bucket <= tcp_hashinfo.ehash_mask; ++st->bucket) { |
| 1922 | struct sock *sk; |
| 1923 | struct hlist_nulls_node *node; |
| 1924 | spinlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket); |
| 1925 | |
| 1926 | /* Lockless fast path for the common case of empty buckets */ |
| 1927 | if (empty_bucket(st)) |
| 1928 | continue; |
| 1929 | |
| 1930 | spin_lock_bh(lock); |
| 1931 | sk_nulls_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) { |
| 1932 | if (sk->sk_family != st->family || |
| 1933 | !net_eq(sock_net(sk), net)) { |
| 1934 | continue; |
| 1935 | } |
| 1936 | rc = sk; |
| 1937 | goto out; |
| 1938 | } |
| 1939 | spin_unlock_bh(lock); |
| 1940 | } |
| 1941 | out: |
| 1942 | return rc; |
| 1943 | } |
| 1944 | |
| 1945 | static void *established_get_next(struct seq_file *seq, void *cur) |
| 1946 | { |
| 1947 | struct sock *sk = cur; |
| 1948 | struct hlist_nulls_node *node; |
| 1949 | struct tcp_iter_state *st = seq->private; |
| 1950 | struct net *net = seq_file_net(seq); |
| 1951 | |
| 1952 | ++st->num; |
| 1953 | ++st->offset; |
| 1954 | |
| 1955 | sk = sk_nulls_next(sk); |
| 1956 | |
| 1957 | sk_nulls_for_each_from(sk, node) { |
| 1958 | if (sk->sk_family == st->family && net_eq(sock_net(sk), net)) |
| 1959 | return sk; |
| 1960 | } |
| 1961 | |
| 1962 | spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket)); |
| 1963 | ++st->bucket; |
| 1964 | return established_get_first(seq); |
| 1965 | } |
| 1966 | |
| 1967 | static void *established_get_idx(struct seq_file *seq, loff_t pos) |
| 1968 | { |
| 1969 | struct tcp_iter_state *st = seq->private; |
| 1970 | void *rc; |
| 1971 | |
| 1972 | st->bucket = 0; |
| 1973 | rc = established_get_first(seq); |
| 1974 | |
| 1975 | while (rc && pos) { |
| 1976 | rc = established_get_next(seq, rc); |
| 1977 | --pos; |
| 1978 | } |
| 1979 | return rc; |
| 1980 | } |
| 1981 | |
| 1982 | static void *tcp_get_idx(struct seq_file *seq, loff_t pos) |
| 1983 | { |
| 1984 | void *rc; |
| 1985 | struct tcp_iter_state *st = seq->private; |
| 1986 | |
| 1987 | st->state = TCP_SEQ_STATE_LISTENING; |
| 1988 | rc = listening_get_idx(seq, &pos); |
| 1989 | |
| 1990 | if (!rc) { |
| 1991 | st->state = TCP_SEQ_STATE_ESTABLISHED; |
| 1992 | rc = established_get_idx(seq, pos); |
| 1993 | } |
| 1994 | |
| 1995 | return rc; |
| 1996 | } |
| 1997 | |
| 1998 | static void *tcp_seek_last_pos(struct seq_file *seq) |
| 1999 | { |
| 2000 | struct tcp_iter_state *st = seq->private; |
| 2001 | int offset = st->offset; |
| 2002 | int orig_num = st->num; |
| 2003 | void *rc = NULL; |
| 2004 | |
| 2005 | switch (st->state) { |
| 2006 | case TCP_SEQ_STATE_LISTENING: |
| 2007 | if (st->bucket >= INET_LHTABLE_SIZE) |
| 2008 | break; |
| 2009 | st->state = TCP_SEQ_STATE_LISTENING; |
| 2010 | rc = listening_get_next(seq, NULL); |
| 2011 | while (offset-- && rc) |
| 2012 | rc = listening_get_next(seq, rc); |
| 2013 | if (rc) |
| 2014 | break; |
| 2015 | st->bucket = 0; |
| 2016 | st->state = TCP_SEQ_STATE_ESTABLISHED; |
| 2017 | /* Fallthrough */ |
| 2018 | case TCP_SEQ_STATE_ESTABLISHED: |
| 2019 | if (st->bucket > tcp_hashinfo.ehash_mask) |
| 2020 | break; |
| 2021 | rc = established_get_first(seq); |
| 2022 | while (offset-- && rc) |
| 2023 | rc = established_get_next(seq, rc); |
| 2024 | } |
| 2025 | |
| 2026 | st->num = orig_num; |
| 2027 | |
| 2028 | return rc; |
| 2029 | } |
| 2030 | |
| 2031 | static void *tcp_seq_start(struct seq_file *seq, loff_t *pos) |
| 2032 | { |
| 2033 | struct tcp_iter_state *st = seq->private; |
| 2034 | void *rc; |
| 2035 | |
| 2036 | if (*pos && *pos == st->last_pos) { |
| 2037 | rc = tcp_seek_last_pos(seq); |
| 2038 | if (rc) |
| 2039 | goto out; |
| 2040 | } |
| 2041 | |
| 2042 | st->state = TCP_SEQ_STATE_LISTENING; |
| 2043 | st->num = 0; |
| 2044 | st->bucket = 0; |
| 2045 | st->offset = 0; |
| 2046 | rc = *pos ? tcp_get_idx(seq, *pos - 1) : SEQ_START_TOKEN; |
| 2047 | |
| 2048 | out: |
| 2049 | st->last_pos = *pos; |
| 2050 | return rc; |
| 2051 | } |
| 2052 | |
| 2053 | static void *tcp_seq_next(struct seq_file *seq, void *v, loff_t *pos) |
| 2054 | { |
| 2055 | struct tcp_iter_state *st = seq->private; |
| 2056 | void *rc = NULL; |
| 2057 | |
| 2058 | if (v == SEQ_START_TOKEN) { |
| 2059 | rc = tcp_get_idx(seq, 0); |
| 2060 | goto out; |
| 2061 | } |
| 2062 | |
| 2063 | switch (st->state) { |
| 2064 | case TCP_SEQ_STATE_LISTENING: |
| 2065 | rc = listening_get_next(seq, v); |
| 2066 | if (!rc) { |
| 2067 | st->state = TCP_SEQ_STATE_ESTABLISHED; |
| 2068 | st->bucket = 0; |
| 2069 | st->offset = 0; |
| 2070 | rc = established_get_first(seq); |
| 2071 | } |
| 2072 | break; |
| 2073 | case TCP_SEQ_STATE_ESTABLISHED: |
| 2074 | rc = established_get_next(seq, v); |
| 2075 | break; |
| 2076 | } |
| 2077 | out: |
| 2078 | ++*pos; |
| 2079 | st->last_pos = *pos; |
| 2080 | return rc; |
| 2081 | } |
| 2082 | |
| 2083 | static void tcp_seq_stop(struct seq_file *seq, void *v) |
| 2084 | { |
| 2085 | struct tcp_iter_state *st = seq->private; |
| 2086 | |
| 2087 | switch (st->state) { |
| 2088 | case TCP_SEQ_STATE_LISTENING: |
| 2089 | if (v != SEQ_START_TOKEN) |
| 2090 | spin_unlock_bh(&tcp_hashinfo.listening_hash[st->bucket].lock); |
| 2091 | break; |
| 2092 | case TCP_SEQ_STATE_ESTABLISHED: |
| 2093 | if (v) |
| 2094 | spin_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket)); |
| 2095 | break; |
| 2096 | } |
| 2097 | } |
| 2098 | |
| 2099 | int tcp_seq_open(struct inode *inode, struct file *file) |
| 2100 | { |
| 2101 | struct tcp_seq_afinfo *afinfo = PDE_DATA(inode); |
| 2102 | struct tcp_iter_state *s; |
| 2103 | int err; |
| 2104 | |
| 2105 | err = seq_open_net(inode, file, &afinfo->seq_ops, |
| 2106 | sizeof(struct tcp_iter_state)); |
| 2107 | if (err < 0) |
| 2108 | return err; |
| 2109 | |
| 2110 | s = ((struct seq_file *)file->private_data)->private; |
| 2111 | s->family = afinfo->family; |
| 2112 | s->last_pos = 0; |
| 2113 | return 0; |
| 2114 | } |
| 2115 | EXPORT_SYMBOL(tcp_seq_open); |
| 2116 | |
| 2117 | int tcp_proc_register(struct net *net, struct tcp_seq_afinfo *afinfo) |
| 2118 | { |
| 2119 | int rc = 0; |
| 2120 | struct proc_dir_entry *p; |
| 2121 | |
| 2122 | afinfo->seq_ops.start = tcp_seq_start; |
| 2123 | afinfo->seq_ops.next = tcp_seq_next; |
| 2124 | afinfo->seq_ops.stop = tcp_seq_stop; |
| 2125 | |
| 2126 | p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net, |
| 2127 | afinfo->seq_fops, afinfo); |
| 2128 | if (!p) |
| 2129 | rc = -ENOMEM; |
| 2130 | return rc; |
| 2131 | } |
| 2132 | EXPORT_SYMBOL(tcp_proc_register); |
| 2133 | |
| 2134 | void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo) |
| 2135 | { |
| 2136 | remove_proc_entry(afinfo->name, net->proc_net); |
| 2137 | } |
| 2138 | EXPORT_SYMBOL(tcp_proc_unregister); |
| 2139 | |
| 2140 | static void get_openreq4(const struct request_sock *req, |
| 2141 | struct seq_file *f, int i) |
| 2142 | { |
| 2143 | const struct inet_request_sock *ireq = inet_rsk(req); |
| 2144 | long delta = req->rsk_timer.expires - jiffies; |
| 2145 | |
| 2146 | seq_printf(f, "%4d: %08X:%04X %08X:%04X" |
| 2147 | " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK", |
| 2148 | i, |
| 2149 | ireq->ir_loc_addr, |
| 2150 | ireq->ir_num, |
| 2151 | ireq->ir_rmt_addr, |
| 2152 | ntohs(ireq->ir_rmt_port), |
| 2153 | TCP_SYN_RECV, |
| 2154 | 0, 0, /* could print option size, but that is af dependent. */ |
| 2155 | 1, /* timers active (only the expire timer) */ |
| 2156 | jiffies_delta_to_clock_t(delta), |
| 2157 | req->num_timeout, |
| 2158 | from_kuid_munged(seq_user_ns(f), |
| 2159 | sock_i_uid(req->rsk_listener)), |
| 2160 | 0, /* non standard timer */ |
| 2161 | 0, /* open_requests have no inode */ |
| 2162 | 0, |
| 2163 | req); |
| 2164 | } |
| 2165 | |
| 2166 | static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i) |
| 2167 | { |
| 2168 | int timer_active; |
| 2169 | unsigned long timer_expires; |
| 2170 | const struct tcp_sock *tp = tcp_sk(sk); |
| 2171 | const struct inet_connection_sock *icsk = inet_csk(sk); |
| 2172 | const struct inet_sock *inet = inet_sk(sk); |
| 2173 | const struct fastopen_queue *fastopenq = &icsk->icsk_accept_queue.fastopenq; |
| 2174 | __be32 dest = inet->inet_daddr; |
| 2175 | __be32 src = inet->inet_rcv_saddr; |
| 2176 | __u16 destp = ntohs(inet->inet_dport); |
| 2177 | __u16 srcp = ntohs(inet->inet_sport); |
| 2178 | int rx_queue; |
| 2179 | int state; |
| 2180 | |
| 2181 | if (icsk->icsk_pending == ICSK_TIME_RETRANS || |
| 2182 | icsk->icsk_pending == ICSK_TIME_EARLY_RETRANS || |
| 2183 | icsk->icsk_pending == ICSK_TIME_LOSS_PROBE) { |
| 2184 | timer_active = 1; |
| 2185 | timer_expires = icsk->icsk_timeout; |
| 2186 | } else if (icsk->icsk_pending == ICSK_TIME_PROBE0) { |
| 2187 | timer_active = 4; |
| 2188 | timer_expires = icsk->icsk_timeout; |
| 2189 | } else if (timer_pending(&sk->sk_timer)) { |
| 2190 | timer_active = 2; |
| 2191 | timer_expires = sk->sk_timer.expires; |
| 2192 | } else { |
| 2193 | timer_active = 0; |
| 2194 | timer_expires = jiffies; |
| 2195 | } |
| 2196 | |
| 2197 | state = sk_state_load(sk); |
| 2198 | if (state == TCP_LISTEN) |
| 2199 | rx_queue = sk->sk_ack_backlog; |
| 2200 | else |
| 2201 | /* Because we don't lock the socket, |
| 2202 | * we might find a transient negative value. |
| 2203 | */ |
| 2204 | rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0); |
| 2205 | |
| 2206 | seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX " |
| 2207 | "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d", |
| 2208 | i, src, srcp, dest, destp, state, |
| 2209 | tp->write_seq - tp->snd_una, |
| 2210 | rx_queue, |
| 2211 | timer_active, |
| 2212 | jiffies_delta_to_clock_t(timer_expires - jiffies), |
| 2213 | icsk->icsk_retransmits, |
| 2214 | from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)), |
| 2215 | icsk->icsk_probes_out, |
| 2216 | sock_i_ino(sk), |
| 2217 | atomic_read(&sk->sk_refcnt), sk, |
| 2218 | jiffies_to_clock_t(icsk->icsk_rto), |
| 2219 | jiffies_to_clock_t(icsk->icsk_ack.ato), |
| 2220 | (icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong, |
| 2221 | tp->snd_cwnd, |
| 2222 | state == TCP_LISTEN ? |
| 2223 | fastopenq->max_qlen : |
| 2224 | (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh)); |
| 2225 | } |
| 2226 | |
| 2227 | static void get_timewait4_sock(const struct inet_timewait_sock *tw, |
| 2228 | struct seq_file *f, int i) |
| 2229 | { |
| 2230 | long delta = tw->tw_timer.expires - jiffies; |
| 2231 | __be32 dest, src; |
| 2232 | __u16 destp, srcp; |
| 2233 | |
| 2234 | dest = tw->tw_daddr; |
| 2235 | src = tw->tw_rcv_saddr; |
| 2236 | destp = ntohs(tw->tw_dport); |
| 2237 | srcp = ntohs(tw->tw_sport); |
| 2238 | |
| 2239 | seq_printf(f, "%4d: %08X:%04X %08X:%04X" |
| 2240 | " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK", |
| 2241 | i, src, srcp, dest, destp, tw->tw_substate, 0, 0, |
| 2242 | 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0, |
| 2243 | atomic_read(&tw->tw_refcnt), tw); |
| 2244 | } |
| 2245 | |
| 2246 | #define TMPSZ 150 |
| 2247 | |
| 2248 | static int tcp4_seq_show(struct seq_file *seq, void *v) |
| 2249 | { |
| 2250 | struct tcp_iter_state *st; |
| 2251 | struct sock *sk = v; |
| 2252 | |
| 2253 | seq_setwidth(seq, TMPSZ - 1); |
| 2254 | if (v == SEQ_START_TOKEN) { |
| 2255 | seq_puts(seq, " sl local_address rem_address st tx_queue " |
| 2256 | "rx_queue tr tm->when retrnsmt uid timeout " |
| 2257 | "inode"); |
| 2258 | goto out; |
| 2259 | } |
| 2260 | st = seq->private; |
| 2261 | |
| 2262 | if (sk->sk_state == TCP_TIME_WAIT) |
| 2263 | get_timewait4_sock(v, seq, st->num); |
| 2264 | else if (sk->sk_state == TCP_NEW_SYN_RECV) |
| 2265 | get_openreq4(v, seq, st->num); |
| 2266 | else |
| 2267 | get_tcp4_sock(v, seq, st->num); |
| 2268 | out: |
| 2269 | seq_pad(seq, '\n'); |
| 2270 | return 0; |
| 2271 | } |
| 2272 | |
| 2273 | static const struct file_operations tcp_afinfo_seq_fops = { |
| 2274 | .owner = THIS_MODULE, |
| 2275 | .open = tcp_seq_open, |
| 2276 | .read = seq_read, |
| 2277 | .llseek = seq_lseek, |
| 2278 | .release = seq_release_net |
| 2279 | }; |
| 2280 | |
| 2281 | static struct tcp_seq_afinfo tcp4_seq_afinfo = { |
| 2282 | .name = "tcp", |
| 2283 | .family = AF_INET, |
| 2284 | .seq_fops = &tcp_afinfo_seq_fops, |
| 2285 | .seq_ops = { |
| 2286 | .show = tcp4_seq_show, |
| 2287 | }, |
| 2288 | }; |
| 2289 | |
| 2290 | static int __net_init tcp4_proc_init_net(struct net *net) |
| 2291 | { |
| 2292 | return tcp_proc_register(net, &tcp4_seq_afinfo); |
| 2293 | } |
| 2294 | |
| 2295 | static void __net_exit tcp4_proc_exit_net(struct net *net) |
| 2296 | { |
| 2297 | tcp_proc_unregister(net, &tcp4_seq_afinfo); |
| 2298 | } |
| 2299 | |
| 2300 | static struct pernet_operations tcp4_net_ops = { |
| 2301 | .init = tcp4_proc_init_net, |
| 2302 | .exit = tcp4_proc_exit_net, |
| 2303 | }; |
| 2304 | |
| 2305 | int __init tcp4_proc_init(void) |
| 2306 | { |
| 2307 | return register_pernet_subsys(&tcp4_net_ops); |
| 2308 | } |
| 2309 | |
| 2310 | void tcp4_proc_exit(void) |
| 2311 | { |
| 2312 | unregister_pernet_subsys(&tcp4_net_ops); |
| 2313 | } |
| 2314 | #endif /* CONFIG_PROC_FS */ |
| 2315 | |
| 2316 | struct proto tcp_prot = { |
| 2317 | .name = "TCP", |
| 2318 | .owner = THIS_MODULE, |
| 2319 | .close = tcp_close, |
| 2320 | .connect = tcp_v4_connect, |
| 2321 | .disconnect = tcp_disconnect, |
| 2322 | .accept = inet_csk_accept, |
| 2323 | .ioctl = tcp_ioctl, |
| 2324 | .init = tcp_v4_init_sock, |
| 2325 | .destroy = tcp_v4_destroy_sock, |
| 2326 | .shutdown = tcp_shutdown, |
| 2327 | .setsockopt = tcp_setsockopt, |
| 2328 | .getsockopt = tcp_getsockopt, |
| 2329 | .recvmsg = tcp_recvmsg, |
| 2330 | .sendmsg = tcp_sendmsg, |
| 2331 | .sendpage = tcp_sendpage, |
| 2332 | .backlog_rcv = tcp_v4_do_rcv, |
| 2333 | .release_cb = tcp_release_cb, |
| 2334 | .hash = inet_hash, |
| 2335 | .unhash = inet_unhash, |
| 2336 | .get_port = inet_csk_get_port, |
| 2337 | .enter_memory_pressure = tcp_enter_memory_pressure, |
| 2338 | .stream_memory_free = tcp_stream_memory_free, |
| 2339 | .sockets_allocated = &tcp_sockets_allocated, |
| 2340 | .orphan_count = &tcp_orphan_count, |
| 2341 | .memory_allocated = &tcp_memory_allocated, |
| 2342 | .memory_pressure = &tcp_memory_pressure, |
| 2343 | .sysctl_mem = sysctl_tcp_mem, |
| 2344 | .sysctl_wmem = sysctl_tcp_wmem, |
| 2345 | .sysctl_rmem = sysctl_tcp_rmem, |
| 2346 | .max_header = MAX_TCP_HEADER, |
| 2347 | .obj_size = sizeof(struct tcp_sock), |
| 2348 | .slab_flags = SLAB_DESTROY_BY_RCU, |
| 2349 | .twsk_prot = &tcp_timewait_sock_ops, |
| 2350 | .rsk_prot = &tcp_request_sock_ops, |
| 2351 | .h.hashinfo = &tcp_hashinfo, |
| 2352 | .no_autobind = true, |
| 2353 | #ifdef CONFIG_COMPAT |
| 2354 | .compat_setsockopt = compat_tcp_setsockopt, |
| 2355 | .compat_getsockopt = compat_tcp_getsockopt, |
| 2356 | #endif |
| 2357 | .diag_destroy = tcp_abort, |
| 2358 | }; |
| 2359 | EXPORT_SYMBOL(tcp_prot); |
| 2360 | |
| 2361 | static void __net_exit tcp_sk_exit(struct net *net) |
| 2362 | { |
| 2363 | int cpu; |
| 2364 | |
| 2365 | for_each_possible_cpu(cpu) |
| 2366 | inet_ctl_sock_destroy(*per_cpu_ptr(net->ipv4.tcp_sk, cpu)); |
| 2367 | free_percpu(net->ipv4.tcp_sk); |
| 2368 | } |
| 2369 | |
| 2370 | static int __net_init tcp_sk_init(struct net *net) |
| 2371 | { |
| 2372 | int res, cpu; |
| 2373 | |
| 2374 | net->ipv4.tcp_sk = alloc_percpu(struct sock *); |
| 2375 | if (!net->ipv4.tcp_sk) |
| 2376 | return -ENOMEM; |
| 2377 | |
| 2378 | for_each_possible_cpu(cpu) { |
| 2379 | struct sock *sk; |
| 2380 | |
| 2381 | res = inet_ctl_sock_create(&sk, PF_INET, SOCK_RAW, |
| 2382 | IPPROTO_TCP, net); |
| 2383 | if (res) |
| 2384 | goto fail; |
| 2385 | sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); |
| 2386 | *per_cpu_ptr(net->ipv4.tcp_sk, cpu) = sk; |
| 2387 | } |
| 2388 | |
| 2389 | net->ipv4.sysctl_tcp_ecn = 2; |
| 2390 | net->ipv4.sysctl_tcp_ecn_fallback = 1; |
| 2391 | |
| 2392 | net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS; |
| 2393 | net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD; |
| 2394 | net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL; |
| 2395 | |
| 2396 | net->ipv4.sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME; |
| 2397 | net->ipv4.sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES; |
| 2398 | net->ipv4.sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL; |
| 2399 | |
| 2400 | net->ipv4.sysctl_tcp_syn_retries = TCP_SYN_RETRIES; |
| 2401 | net->ipv4.sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES; |
| 2402 | net->ipv4.sysctl_tcp_syncookies = 1; |
| 2403 | net->ipv4.sysctl_tcp_reordering = TCP_FASTRETRANS_THRESH; |
| 2404 | net->ipv4.sysctl_tcp_retries1 = TCP_RETR1; |
| 2405 | net->ipv4.sysctl_tcp_retries2 = TCP_RETR2; |
| 2406 | net->ipv4.sysctl_tcp_orphan_retries = 0; |
| 2407 | net->ipv4.sysctl_tcp_fin_timeout = TCP_FIN_TIMEOUT; |
| 2408 | net->ipv4.sysctl_tcp_notsent_lowat = UINT_MAX; |
| 2409 | |
| 2410 | return 0; |
| 2411 | fail: |
| 2412 | tcp_sk_exit(net); |
| 2413 | |
| 2414 | return res; |
| 2415 | } |
| 2416 | |
| 2417 | static void __net_exit tcp_sk_exit_batch(struct list_head *net_exit_list) |
| 2418 | { |
| 2419 | inet_twsk_purge(&tcp_hashinfo, &tcp_death_row, AF_INET); |
| 2420 | } |
| 2421 | |
| 2422 | static struct pernet_operations __net_initdata tcp_sk_ops = { |
| 2423 | .init = tcp_sk_init, |
| 2424 | .exit = tcp_sk_exit, |
| 2425 | .exit_batch = tcp_sk_exit_batch, |
| 2426 | }; |
| 2427 | |
| 2428 | void __init tcp_v4_init(void) |
| 2429 | { |
| 2430 | inet_hashinfo_init(&tcp_hashinfo); |
| 2431 | if (register_pernet_subsys(&tcp_sk_ops)) |
| 2432 | panic("Failed to create the TCP control socket.\n"); |
| 2433 | } |