net/rxrpc/peer_event.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* Peer event handling, typically ICMP messages.
   3  *
   4  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/net.h>
  10 #include <linux/skbuff.h>
  11 #include <linux/errqueue.h>
  12 #include <linux/udp.h>
  13 #include <linux/in.h>
  14 #include <linux/in6.h>
  15 #include <linux/icmp.h>
  16 #include <net/sock.h>
  17 #include <net/af_rxrpc.h>
  18 #include <net/ip.h>
  19 #include <net/icmp.h>
  20 #include "ar-internal.h"
  21
  22 static void rxrpc_adjust_mtu(struct rxrpc_peer *, unsigned int);
  23 static void rxrpc_store_error(struct rxrpc_peer *, struct sock_exterr_skb *);
  24 static void rxrpc_distribute_error(struct rxrpc_peer *, int,
  25                                    enum rxrpc_call_completion);
  26
  27 /*
  28  * Find the peer associated with an ICMPv4 packet.
  29  */
  30 static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local,
  31                                                      struct sk_buff *skb,
  32                                                      unsigned int udp_offset,
  33                                                      unsigned int *info,
  34                                                      struct sockaddr_rxrpc *srx)
  35 {
  36         struct iphdr *ip, *ip0 = ip_hdr(skb);
  37         struct icmphdr *icmp = icmp_hdr(skb);
  38         struct udphdr *udp = (struct udphdr *)(skb->data + udp_offset);
  39
  40         _enter("%u,%u,%u", ip0->protocol, icmp->type, icmp->code);
  41
  42         switch (icmp->type) {
  43         case ICMP_DEST_UNREACH:
  44                 *info = ntohs(icmp->un.frag.mtu);
  45                 fallthrough;
  46         case ICMP_TIME_EXCEEDED:
  47         case ICMP_PARAMETERPROB:
  48                 ip = (struct iphdr *)((void *)icmp + 8);
  49                 break;
  50         default:
  51                 return NULL;
  52         }
  53
  54         memset(srx, 0, sizeof(*srx));
  55         srx->transport_type = local->srx.transport_type;
  56         srx->transport_len = local->srx.transport_len;
  57         srx->transport.family = local->srx.transport.family;
  58
  59         /* Can we see an ICMP4 packet on an ICMP6 listening socket?  and vice
  60          * versa?
  61          */
  62         switch (srx->transport.family) {
  63         case AF_INET:
  64                 srx->transport_len = sizeof(srx->transport.sin);
  65                 srx->transport.family = AF_INET;
  66                 srx->transport.sin.sin_port = udp->dest;
  67                 memcpy(&srx->transport.sin.sin_addr, &ip->daddr,
  68                        sizeof(struct in_addr));
  69                 break;
  70
  71 #ifdef CONFIG_AF_RXRPC_IPV6
  72         case AF_INET6:
  73                 srx->transport_len = sizeof(srx->transport.sin);
  74                 srx->transport.family = AF_INET;
  75                 srx->transport.sin.sin_port = udp->dest;
  76                 memcpy(&srx->transport.sin.sin_addr, &ip->daddr,
  77                        sizeof(struct in_addr));
  78                 break;
  79 #endif
  80
  81         default:
  82                 WARN_ON_ONCE(1);
  83                 return NULL;
  84         }
  85
  86         _net("ICMP {%pISp}", &srx->transport);
  87         return rxrpc_lookup_peer_rcu(local, srx);
  88 }
  89
  90 #ifdef CONFIG_AF_RXRPC_IPV6
  91 /*
  92  * Find the peer associated with an ICMPv6 packet.
  93  */
  94 static struct rxrpc_peer *rxrpc_lookup_peer_icmp6_rcu(struct rxrpc_local *local,
  95                                                       struct sk_buff *skb,
  96                                                       unsigned int udp_offset,
  97                                                       unsigned int *info,
  98                                                       struct sockaddr_rxrpc *srx)
  99 {
 100         struct icmp6hdr *icmp = icmp6_hdr(skb);
 101         struct ipv6hdr *ip, *ip0 = ipv6_hdr(skb);
 102         struct udphdr *udp = (struct udphdr *)(skb->data + udp_offset);
 103
 104         _enter("%u,%u,%u", ip0->nexthdr, icmp->icmp6_type, icmp->icmp6_code);
 105
 106         switch (icmp->icmp6_type) {
 107         case ICMPV6_DEST_UNREACH:
 108                 *info = ntohl(icmp->icmp6_mtu);
 109                 fallthrough;
 110         case ICMPV6_PKT_TOOBIG:
 111         case ICMPV6_TIME_EXCEED:
 112         case ICMPV6_PARAMPROB:
 113                 ip = (struct ipv6hdr *)((void *)icmp + 8);
 114                 break;
 115         default:
 116                 return NULL;
 117         }
 118
 119         memset(srx, 0, sizeof(*srx));
 120         srx->transport_type = local->srx.transport_type;
 121         srx->transport_len = local->srx.transport_len;
 122         srx->transport.family = local->srx.transport.family;
 123
 124         /* Can we see an ICMP4 packet on an ICMP6 listening socket?  and vice
 125          * versa?
 126          */
 127         switch (srx->transport.family) {
 128         case AF_INET:
 129                 _net("Rx ICMP6 on v4 sock");
 130                 srx->transport_len = sizeof(srx->transport.sin);
 131                 srx->transport.family = AF_INET;
 132                 srx->transport.sin.sin_port = udp->dest;
 133                 memcpy(&srx->transport.sin.sin_addr,
 134                        &ip->daddr.s6_addr32[3], sizeof(struct in_addr));
 135                 break;
 136         case AF_INET6:
 137                 _net("Rx ICMP6");
 138                 srx->transport.sin.sin_port = udp->dest;
 139                 memcpy(&srx->transport.sin6.sin6_addr, &ip->daddr,
 140                        sizeof(struct in6_addr));
 141                 break;
 142         default:
 143                 WARN_ON_ONCE(1);
 144                 return NULL;
 145         }
 146
 147         _net("ICMP {%pISp}", &srx->transport);
 148         return rxrpc_lookup_peer_rcu(local, srx);
 149 }
 150 #endif /* CONFIG_AF_RXRPC_IPV6 */
 151
 152 /*
 153  * Handle an error received on the local endpoint as a tunnel.
 154  */
 155 void rxrpc_encap_err_rcv(struct sock *sk, struct sk_buff *skb,
 156                          unsigned int udp_offset)
 157 {
 158         struct sock_extended_err ee;
 159         struct sockaddr_rxrpc srx;
 160         struct rxrpc_local *local;
 161         struct rxrpc_peer *peer;
 162         unsigned int info = 0;
 163         int err;
 164         u8 version = ip_hdr(skb)->version;
 165         u8 type = icmp_hdr(skb)->type;
 166         u8 code = icmp_hdr(skb)->code;
 167
 168         rcu_read_lock();
 169         local = rcu_dereference_sk_user_data(sk);
 170         if (unlikely(!local)) {
 171                 rcu_read_unlock();
 172                 return;
 173         }
 174
 175         rxrpc_new_skb(skb, rxrpc_skb_received);
 176
 177         switch (ip_hdr(skb)->version) {
 178         case IPVERSION:
 179                 peer = rxrpc_lookup_peer_icmp_rcu(local, skb, udp_offset,
 180                                                   &info, &srx);
 181                 break;
 182 #ifdef CONFIG_AF_RXRPC_IPV6
 183         case 6:
 184                 peer = rxrpc_lookup_peer_icmp6_rcu(local, skb, udp_offset,
 185                                                    &info, &srx);
 186                 break;
 187 #endif
 188         default:
 189                 rcu_read_unlock();
 190                 return;
 191         }
 192
 193         if (peer && !rxrpc_get_peer_maybe(peer))
 194                 peer = NULL;
 195         if (!peer) {
 196                 rcu_read_unlock();
 197                 return;
 198         }
 199
 200         memset(&ee, 0, sizeof(ee));
 201
 202         switch (version) {
 203         case IPVERSION:
 204                 switch (type) {
 205                 case ICMP_DEST_UNREACH:
 206                         switch (code) {
 207                         case ICMP_FRAG_NEEDED:
 208                                 rxrpc_adjust_mtu(peer, info);
 209                                 rcu_read_unlock();
 210                                 rxrpc_put_peer(peer);
 211                                 return;
 212                         default:
 213                                 break;
 214                         }
 215
 216                         err = EHOSTUNREACH;
 217                         if (code <= NR_ICMP_UNREACH) {
 218                                 /* Might want to do something different with
 219                                  * non-fatal errors
 220                                  */
 221                                 //harderr = icmp_err_convert[code].fatal;
 222                                 err = icmp_err_convert[code].errno;
 223                         }
 224                         break;
 225
 226                 case ICMP_TIME_EXCEEDED:
 227                         err = EHOSTUNREACH;
 228                         break;
 229                 default:
 230                         err = EPROTO;
 231                         break;
 232                 }
 233
 234                 ee.ee_origin = SO_EE_ORIGIN_ICMP;
 235                 ee.ee_type = type;
 236                 ee.ee_code = code;
 237                 ee.ee_errno = err;
 238                 break;
 239
 240 #ifdef CONFIG_AF_RXRPC_IPV6
 241         case 6:
 242                 switch (type) {
 243                 case ICMPV6_PKT_TOOBIG:
 244                         rxrpc_adjust_mtu(peer, info);
 245                         rcu_read_unlock();
 246                         rxrpc_put_peer(peer);
 247                         return;
 248                 }
 249
 250                 icmpv6_err_convert(type, code, &err);
 251
 252                 if (err == EACCES)
 253                         err = EHOSTUNREACH;
 254
 255                 ee.ee_origin = SO_EE_ORIGIN_ICMP6;
 256                 ee.ee_type = type;
 257                 ee.ee_code = code;
 258                 ee.ee_errno = err;
 259                 break;
 260 #endif
 261         }
 262
 263         trace_rxrpc_rx_icmp(peer, &ee, &srx);
 264
 265         rxrpc_distribute_error(peer, err, RXRPC_CALL_NETWORK_ERROR);
 266         rcu_read_unlock();
 267         rxrpc_put_peer(peer);
 268 }
 269
 270 /*
 271  * Find the peer associated with a local error.
 272  */
 273 static struct rxrpc_peer *rxrpc_lookup_peer_local_rcu(struct rxrpc_local *local,
 274                                                       const struct sk_buff *skb,
 275                                                       struct sockaddr_rxrpc *srx)
 276 {
 277         struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
 278
 279         _enter("");
 280
 281         memset(srx, 0, sizeof(*srx));
 282         srx->transport_type = local->srx.transport_type;
 283         srx->transport_len = local->srx.transport_len;
 284         srx->transport.family = local->srx.transport.family;
 285
 286         switch (srx->transport.family) {
 287         case AF_INET:
 288                 srx->transport_len = sizeof(srx->transport.sin);
 289                 srx->transport.family = AF_INET;
 290                 srx->transport.sin.sin_port = serr->port;
 291                 switch (serr->ee.ee_origin) {
 292                 case SO_EE_ORIGIN_ICMP:
 293                         _net("Rx ICMP");
 294                         memcpy(&srx->transport.sin.sin_addr,
 295                                skb_network_header(skb) + serr->addr_offset,
 296                                sizeof(struct in_addr));
 297                         break;
 298                 case SO_EE_ORIGIN_ICMP6:
 299                         _net("Rx ICMP6 on v4 sock");
 300                         memcpy(&srx->transport.sin.sin_addr,
 301                                skb_network_header(skb) + serr->addr_offset + 12,
 302                                sizeof(struct in_addr));
 303                         break;
 304                 default:
 305                         memcpy(&srx->transport.sin.sin_addr, &ip_hdr(skb)->saddr,
 306                                sizeof(struct in_addr));
 307                         break;
 308                 }
 309                 break;
 310
 311 #ifdef CONFIG_AF_RXRPC_IPV6
 312         case AF_INET6:
 313                 switch (serr->ee.ee_origin) {
 314                 case SO_EE_ORIGIN_ICMP6:
 315                         _net("Rx ICMP6");
 316                         srx->transport.sin6.sin6_port = serr->port;
 317                         memcpy(&srx->transport.sin6.sin6_addr,
 318                                skb_network_header(skb) + serr->addr_offset,
 319                                sizeof(struct in6_addr));
 320                         break;
 321                 case SO_EE_ORIGIN_ICMP:
 322                         _net("Rx ICMP on v6 sock");
 323                         srx->transport_len = sizeof(srx->transport.sin);
 324                         srx->transport.family = AF_INET;
 325                         srx->transport.sin.sin_port = serr->port;
 326                         memcpy(&srx->transport.sin.sin_addr,
 327                                skb_network_header(skb) + serr->addr_offset,
 328                                sizeof(struct in_addr));
 329                         break;
 330                 default:
 331                         memcpy(&srx->transport.sin6.sin6_addr,
 332                                &ipv6_hdr(skb)->saddr,
 333                                sizeof(struct in6_addr));
 334                         break;
 335                 }
 336                 break;
 337 #endif
 338
 339         default:
 340                 BUG();
 341         }
 342
 343         return rxrpc_lookup_peer_rcu(local, srx);
 344 }
 345
 346 /*
 347  * Handle an MTU/fragmentation problem.
 348  */
 349 static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, unsigned int mtu)
 350 {
 351         _net("Rx ICMP Fragmentation Needed (%d)", mtu);
 352
 353         /* wind down the local interface MTU */
 354         if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
 355                 peer->if_mtu = mtu;
 356                 _net("I/F MTU %u", mtu);
 357         }
 358
 359         if (mtu == 0) {
 360                 /* they didn't give us a size, estimate one */
 361                 mtu = peer->if_mtu;
 362                 if (mtu > 1500) {
 363                         mtu >>= 1;
 364                         if (mtu < 1500)
 365                                 mtu = 1500;
 366                 } else {
 367                         mtu -= 100;
 368                         if (mtu < peer->hdrsize)
 369                                 mtu = peer->hdrsize + 4;
 370                 }
 371         }
 372
 373         if (mtu < peer->mtu) {
 374                 spin_lock_bh(&peer->lock);
 375                 peer->mtu = mtu;
 376                 peer->maxdata = peer->mtu - peer->hdrsize;
 377                 spin_unlock_bh(&peer->lock);
 378                 _net("Net MTU %u (maxdata %u)",
 379                      peer->mtu, peer->maxdata);
 380         }
 381 }
 382
 383 /*
 384  * Handle an error received on the local endpoint.
 385  */
 386 void rxrpc_error_report(struct sock *sk)
 387 {
 388         struct sock_exterr_skb *serr;
 389         struct sockaddr_rxrpc srx;
 390         struct rxrpc_local *local;
 391         struct rxrpc_peer *peer = NULL;
 392         struct sk_buff *skb;
 393
 394         rcu_read_lock();
 395         local = rcu_dereference_sk_user_data(sk);
 396         if (unlikely(!local)) {
 397                 rcu_read_unlock();
 398                 return;
 399         }
 400         _enter("%p{%d}", sk, local->debug_id);
 401
 402         /* Clear the outstanding error value on the socket so that it doesn't
 403          * cause kernel_sendmsg() to return it later.
 404          */
 405         sock_error(sk);
 406
 407         skb = sock_dequeue_err_skb(sk);
 408         if (!skb) {
 409                 rcu_read_unlock();
 410                 _leave("UDP socket errqueue empty");
 411                 return;
 412         }
 413         rxrpc_new_skb(skb, rxrpc_skb_received);
 414         serr = SKB_EXT_ERR(skb);
 415
 416         if (serr->ee.ee_origin == SO_EE_ORIGIN_LOCAL) {
 417                 peer = rxrpc_lookup_peer_local_rcu(local, skb, &srx);
 418                 if (peer && !rxrpc_get_peer_maybe(peer))
 419                         peer = NULL;
 420                 if (peer) {
 421                         trace_rxrpc_rx_icmp(peer, &serr->ee, &srx);
 422                         rxrpc_store_error(peer, serr);
 423                 }
 424         }
 425
 426         rcu_read_unlock();
 427         rxrpc_free_skb(skb, rxrpc_skb_freed);
 428         rxrpc_put_peer(peer);
 429         _leave("");
 430 }
 431
 432 /*
 433  * Map an error report to error codes on the peer record.
 434  */
 435 static void rxrpc_store_error(struct rxrpc_peer *peer,
 436                               struct sock_exterr_skb *serr)
 437 {
 438         enum rxrpc_call_completion compl = RXRPC_CALL_NETWORK_ERROR;
 439         struct sock_extended_err *ee;
 440         int err;
 441
 442         _enter("");
 443
 444         ee = &serr->ee;
 445
 446         err = ee->ee_errno;
 447
 448         switch (ee->ee_origin) {
 449         case SO_EE_ORIGIN_ICMP:
 450                 switch (ee->ee_type) {
 451                 case ICMP_DEST_UNREACH:
 452                         switch (ee->ee_code) {
 453                         case ICMP_NET_UNREACH:
 454                                 _net("Rx Received ICMP Network Unreachable");
 455                                 break;
 456                         case ICMP_HOST_UNREACH:
 457                                 _net("Rx Received ICMP Host Unreachable");
 458                                 break;
 459                         case ICMP_PORT_UNREACH:
 460                                 _net("Rx Received ICMP Port Unreachable");
 461                                 break;
 462                         case ICMP_NET_UNKNOWN:
 463                                 _net("Rx Received ICMP Unknown Network");
 464                                 break;
 465                         case ICMP_HOST_UNKNOWN:
 466                                 _net("Rx Received ICMP Unknown Host");
 467                                 break;
 468                         default:
 469                                 _net("Rx Received ICMP DestUnreach code=%u",
 470                                      ee->ee_code);
 471                                 break;
 472                         }
 473                         break;
 474
 475                 case ICMP_TIME_EXCEEDED:
 476                         _net("Rx Received ICMP TTL Exceeded");
 477                         break;
 478
 479                 default:
 480                         _proto("Rx Received ICMP error { type=%u code=%u }",
 481                                ee->ee_type, ee->ee_code);
 482                         break;
 483                 }
 484                 break;
 485
 486         case SO_EE_ORIGIN_NONE:
 487         case SO_EE_ORIGIN_LOCAL:
 488                 _proto("Rx Received local error { error=%d }", err);
 489                 compl = RXRPC_CALL_LOCAL_ERROR;
 490                 break;
 491
 492         case SO_EE_ORIGIN_ICMP6:
 493                 if (err == EACCES)
 494                         err = EHOSTUNREACH;
 495                 fallthrough;
 496         default:
 497                 _proto("Rx Received error report { orig=%u }", ee->ee_origin);
 498                 break;
 499         }
 500
 501         rxrpc_distribute_error(peer, err, compl);
 502 }
 503
 504 /*
 505  * Distribute an error that occurred on a peer.
 506  */
 507 static void rxrpc_distribute_error(struct rxrpc_peer *peer, int error,
 508                                    enum rxrpc_call_completion compl)
 509 {
 510         struct rxrpc_call *call;
 511
 512         hlist_for_each_entry_rcu(call, &peer->error_targets, error_link) {
 513                 rxrpc_see_call(call);
 514                 rxrpc_set_call_completion(call, compl, 0, -error);
 515         }
 516 }
 517
 518 /*
 519  * Perform keep-alive pings.
 520  */
 521 static void rxrpc_peer_keepalive_dispatch(struct rxrpc_net *rxnet,
 522                                           struct list_head *collector,
 523                                           time64_t base,
 524                                           u8 cursor)
 525 {
 526         struct rxrpc_peer *peer;
 527         const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1;
 528         time64_t keepalive_at;
 529         int slot;
 530
 531         spin_lock_bh(&rxnet->peer_hash_lock);
 532
 533         while (!list_empty(collector)) {
 534                 peer = list_entry(collector->next,
 535                                   struct rxrpc_peer, keepalive_link);
 536
 537                 list_del_init(&peer->keepalive_link);
 538                 if (!rxrpc_get_peer_maybe(peer))
 539                         continue;
 540
 541                 if (__rxrpc_use_local(peer->local)) {
 542                         spin_unlock_bh(&rxnet->peer_hash_lock);
 543
 544                         keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME;
 545                         slot = keepalive_at - base;
 546                         _debug("%02x peer %u t=%d {%pISp}",
 547                                cursor, peer->debug_id, slot, &peer->srx.transport);
 548
 549                         if (keepalive_at <= base ||
 550                             keepalive_at > base + RXRPC_KEEPALIVE_TIME) {
 551                                 rxrpc_send_keepalive(peer);
 552                                 slot = RXRPC_KEEPALIVE_TIME;
 553                         }
 554
 555                         /* A transmission to this peer occurred since last we
 556                          * examined it so put it into the appropriate future
 557                          * bucket.
 558                          */
 559                         slot += cursor;
 560                         slot &= mask;
 561                         spin_lock_bh(&rxnet->peer_hash_lock);
 562                         list_add_tail(&peer->keepalive_link,
 563                                       &rxnet->peer_keepalive[slot & mask]);
 564                         rxrpc_unuse_local(peer->local);
 565                 }
 566                 rxrpc_put_peer_locked(peer);
 567         }
 568
 569         spin_unlock_bh(&rxnet->peer_hash_lock);
 570 }
 571
 572 /*
 573  * Perform keep-alive pings with VERSION packets to keep any NAT alive.
 574  */
 575 void rxrpc_peer_keepalive_worker(struct work_struct *work)
 576 {
 577         struct rxrpc_net *rxnet =
 578                 container_of(work, struct rxrpc_net, peer_keepalive_work);
 579         const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1;
 580         time64_t base, now, delay;
 581         u8 cursor, stop;
 582         LIST_HEAD(collector);
 583
 584         now = ktime_get_seconds();
 585         base = rxnet->peer_keepalive_base;
 586         cursor = rxnet->peer_keepalive_cursor;
 587         _enter("%lld,%u", base - now, cursor);
 588
 589         if (!rxnet->live)
 590                 return;
 591
 592         /* Remove to a temporary list all the peers that are currently lodged
 593          * in expired buckets plus all new peers.
 594          *
 595          * Everything in the bucket at the cursor is processed this
 596          * second; the bucket at cursor + 1 goes at now + 1s and so
 597          * on...
 598          */
 599         spin_lock_bh(&rxnet->peer_hash_lock);
 600         list_splice_init(&rxnet->peer_keepalive_new, &collector);
 601
 602         stop = cursor + ARRAY_SIZE(rxnet->peer_keepalive);
 603         while (base <= now && (s8)(cursor - stop) < 0) {
 604                 list_splice_tail_init(&rxnet->peer_keepalive[cursor & mask],
 605                                       &collector);
 606                 base++;
 607                 cursor++;
 608         }
 609
 610         base = now;
 611         spin_unlock_bh(&rxnet->peer_hash_lock);
 612
 613         rxnet->peer_keepalive_base = base;
 614         rxnet->peer_keepalive_cursor = cursor;
 615         rxrpc_peer_keepalive_dispatch(rxnet, &collector, base, cursor);
 616         ASSERT(list_empty(&collector));
 617
 618         /* Schedule the timer for the next occupied timeslot. */
 619         cursor = rxnet->peer_keepalive_cursor;
 620         stop = cursor + RXRPC_KEEPALIVE_TIME - 1;
 621         for (; (s8)(cursor - stop) < 0; cursor++) {
 622                 if (!list_empty(&rxnet->peer_keepalive[cursor & mask]))
 623                         break;
 624                 base++;
 625         }
 626
 627         now = ktime_get_seconds();
 628         delay = base - now;
 629         if (delay < 1)
 630                 delay = 1;
 631         delay *= HZ;
 632         if (rxnet->live)
 633                 timer_reduce(&rxnet->peer_keepalive_timer, jiffies + delay);
 634
 635         _leave("");
 636 }