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 "ar-internal.h"
  20
  21 static void rxrpc_store_error(struct rxrpc_peer *, struct sock_exterr_skb *);
  22 static void rxrpc_distribute_error(struct rxrpc_peer *, int,
  23                                    enum rxrpc_call_completion);
  24
  25 /*
  26  * Find the peer associated with an ICMP packet.
  27  */
  28 static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local,
  29                                                      const struct sk_buff *skb,
  30                                                      struct sockaddr_rxrpc *srx)
  31 {
  32         struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
  33
  34         _enter("");
  35
  36         memset(srx, 0, sizeof(*srx));
  37         srx->transport_type = local->srx.transport_type;
  38         srx->transport_len = local->srx.transport_len;
  39         srx->transport.family = local->srx.transport.family;
  40
  41         /* Can we see an ICMP4 packet on an ICMP6 listening socket?  and vice
  42          * versa?
  43          */
  44         switch (srx->transport.family) {
  45         case AF_INET:
  46                 srx->transport_len = sizeof(srx->transport.sin);
  47                 srx->transport.family = AF_INET;
  48                 srx->transport.sin.sin_port = serr->port;
  49                 switch (serr->ee.ee_origin) {
  50                 case SO_EE_ORIGIN_ICMP:
  51                         _net("Rx ICMP");
  52                         memcpy(&srx->transport.sin.sin_addr,
  53                                skb_network_header(skb) + serr->addr_offset,
  54                                sizeof(struct in_addr));
  55                         break;
  56                 case SO_EE_ORIGIN_ICMP6:
  57                         _net("Rx ICMP6 on v4 sock");
  58                         memcpy(&srx->transport.sin.sin_addr,
  59                                skb_network_header(skb) + serr->addr_offset + 12,
  60                                sizeof(struct in_addr));
  61                         break;
  62                 default:
  63                         memcpy(&srx->transport.sin.sin_addr, &ip_hdr(skb)->saddr,
  64                                sizeof(struct in_addr));
  65                         break;
  66                 }
  67                 break;
  68
  69 #ifdef CONFIG_AF_RXRPC_IPV6
  70         case AF_INET6:
  71                 switch (serr->ee.ee_origin) {
  72                 case SO_EE_ORIGIN_ICMP6:
  73                         _net("Rx ICMP6");
  74                         srx->transport.sin6.sin6_port = serr->port;
  75                         memcpy(&srx->transport.sin6.sin6_addr,
  76                                skb_network_header(skb) + serr->addr_offset,
  77                                sizeof(struct in6_addr));
  78                         break;
  79                 case SO_EE_ORIGIN_ICMP:
  80                         _net("Rx ICMP on v6 sock");
  81                         srx->transport_len = sizeof(srx->transport.sin);
  82                         srx->transport.family = AF_INET;
  83                         srx->transport.sin.sin_port = serr->port;
  84                         memcpy(&srx->transport.sin.sin_addr,
  85                                skb_network_header(skb) + serr->addr_offset,
  86                                sizeof(struct in_addr));
  87                         break;
  88                 default:
  89                         memcpy(&srx->transport.sin6.sin6_addr,
  90                                &ipv6_hdr(skb)->saddr,
  91                                sizeof(struct in6_addr));
  92                         break;
  93                 }
  94                 break;
  95 #endif
  96
  97         default:
  98                 BUG();
  99         }
 100
 101         return rxrpc_lookup_peer_rcu(local, srx);
 102 }
 103
 104 /*
 105  * Handle an MTU/fragmentation problem.
 106  */
 107 static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *serr)
 108 {
 109         u32 mtu = serr->ee.ee_info;
 110
 111         _net("Rx ICMP Fragmentation Needed (%d)", mtu);
 112
 113         /* wind down the local interface MTU */
 114         if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
 115                 peer->if_mtu = mtu;
 116                 _net("I/F MTU %u", mtu);
 117         }
 118
 119         if (mtu == 0) {
 120                 /* they didn't give us a size, estimate one */
 121                 mtu = peer->if_mtu;
 122                 if (mtu > 1500) {
 123                         mtu >>= 1;
 124                         if (mtu < 1500)
 125                                 mtu = 1500;
 126                 } else {
 127                         mtu -= 100;
 128                         if (mtu < peer->hdrsize)
 129                                 mtu = peer->hdrsize + 4;
 130                 }
 131         }
 132
 133         if (mtu < peer->mtu) {
 134                 spin_lock_bh(&peer->lock);
 135                 peer->mtu = mtu;
 136                 peer->maxdata = peer->mtu - peer->hdrsize;
 137                 spin_unlock_bh(&peer->lock);
 138                 _net("Net MTU %u (maxdata %u)",
 139                      peer->mtu, peer->maxdata);
 140         }
 141 }
 142
 143 /*
 144  * Handle an error received on the local endpoint.
 145  */
 146 void rxrpc_error_report(struct sock *sk)
 147 {
 148         struct sock_exterr_skb *serr;
 149         struct sockaddr_rxrpc srx;
 150         struct rxrpc_local *local;
 151         struct rxrpc_peer *peer;
 152         struct sk_buff *skb;
 153
 154         rcu_read_lock();
 155         local = rcu_dereference_sk_user_data(sk);
 156         if (unlikely(!local)) {
 157                 rcu_read_unlock();
 158                 return;
 159         }
 160         _enter("%p{%d}", sk, local->debug_id);
 161
 162         /* Clear the outstanding error value on the socket so that it doesn't
 163          * cause kernel_sendmsg() to return it later.
 164          */
 165         sock_error(sk);
 166
 167         skb = sock_dequeue_err_skb(sk);
 168         if (!skb) {
 169                 rcu_read_unlock();
 170                 _leave("UDP socket errqueue empty");
 171                 return;
 172         }
 173         rxrpc_new_skb(skb, rxrpc_skb_received);
 174         serr = SKB_EXT_ERR(skb);
 175         if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
 176                 _leave("UDP empty message");
 177                 rcu_read_unlock();
 178                 rxrpc_free_skb(skb, rxrpc_skb_freed);
 179                 return;
 180         }
 181
 182         peer = rxrpc_lookup_peer_icmp_rcu(local, skb, &srx);
 183         if (peer && !rxrpc_get_peer_maybe(peer))
 184                 peer = NULL;
 185         if (!peer) {
 186                 rcu_read_unlock();
 187                 rxrpc_free_skb(skb, rxrpc_skb_freed);
 188                 _leave(" [no peer]");
 189                 return;
 190         }
 191
 192         trace_rxrpc_rx_icmp(peer, &serr->ee, &srx);
 193
 194         if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
 195              serr->ee.ee_type == ICMP_DEST_UNREACH &&
 196              serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
 197                 rxrpc_adjust_mtu(peer, serr);
 198                 rcu_read_unlock();
 199                 rxrpc_free_skb(skb, rxrpc_skb_freed);
 200                 rxrpc_put_peer(peer);
 201                 _leave(" [MTU update]");
 202                 return;
 203         }
 204
 205         rxrpc_store_error(peer, serr);
 206         rcu_read_unlock();
 207         rxrpc_free_skb(skb, rxrpc_skb_freed);
 208         rxrpc_put_peer(peer);
 209
 210         _leave("");
 211 }
 212
 213 /*
 214  * Map an error report to error codes on the peer record.
 215  */
 216 static void rxrpc_store_error(struct rxrpc_peer *peer,
 217                               struct sock_exterr_skb *serr)
 218 {
 219         enum rxrpc_call_completion compl = RXRPC_CALL_NETWORK_ERROR;
 220         struct sock_extended_err *ee;
 221         int err;
 222
 223         _enter("");
 224
 225         ee = &serr->ee;
 226
 227         err = ee->ee_errno;
 228
 229         switch (ee->ee_origin) {
 230         case SO_EE_ORIGIN_ICMP:
 231                 switch (ee->ee_type) {
 232                 case ICMP_DEST_UNREACH:
 233                         switch (ee->ee_code) {
 234                         case ICMP_NET_UNREACH:
 235                                 _net("Rx Received ICMP Network Unreachable");
 236                                 break;
 237                         case ICMP_HOST_UNREACH:
 238                                 _net("Rx Received ICMP Host Unreachable");
 239                                 break;
 240                         case ICMP_PORT_UNREACH:
 241                                 _net("Rx Received ICMP Port Unreachable");
 242                                 break;
 243                         case ICMP_NET_UNKNOWN:
 244                                 _net("Rx Received ICMP Unknown Network");
 245                                 break;
 246                         case ICMP_HOST_UNKNOWN:
 247                                 _net("Rx Received ICMP Unknown Host");
 248                                 break;
 249                         default:
 250                                 _net("Rx Received ICMP DestUnreach code=%u",
 251                                      ee->ee_code);
 252                                 break;
 253                         }
 254                         break;
 255
 256                 case ICMP_TIME_EXCEEDED:
 257                         _net("Rx Received ICMP TTL Exceeded");
 258                         break;
 259
 260                 default:
 261                         _proto("Rx Received ICMP error { type=%u code=%u }",
 262                                ee->ee_type, ee->ee_code);
 263                         break;
 264                 }
 265                 break;
 266
 267         case SO_EE_ORIGIN_NONE:
 268         case SO_EE_ORIGIN_LOCAL:
 269                 _proto("Rx Received local error { error=%d }", err);
 270                 compl = RXRPC_CALL_LOCAL_ERROR;
 271                 break;
 272
 273         case SO_EE_ORIGIN_ICMP6:
 274         default:
 275                 _proto("Rx Received error report { orig=%u }", ee->ee_origin);
 276                 break;
 277         }
 278
 279         rxrpc_distribute_error(peer, err, compl);
 280 }
 281
 282 /*
 283  * Distribute an error that occurred on a peer.
 284  */
 285 static void rxrpc_distribute_error(struct rxrpc_peer *peer, int error,
 286                                    enum rxrpc_call_completion compl)
 287 {
 288         struct rxrpc_call *call;
 289
 290         hlist_for_each_entry_rcu(call, &peer->error_targets, error_link) {
 291                 rxrpc_see_call(call);
 292                 if (call->state < RXRPC_CALL_COMPLETE &&
 293                     rxrpc_set_call_completion(call, compl, 0, -error))
 294                         rxrpc_notify_socket(call);
 295         }
 296 }
 297
 298 /*
 299  * Add RTT information to cache.  This is called in softirq mode and has
 300  * exclusive access to the peer RTT data.
 301  */
 302 void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
 303                         rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,
 304                         ktime_t send_time, ktime_t resp_time)
 305 {
 306         struct rxrpc_peer *peer = call->peer;
 307         s64 rtt;
 308         u64 sum = peer->rtt_sum, avg;
 309         u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage;
 310
 311         rtt = ktime_to_ns(ktime_sub(resp_time, send_time));
 312         if (rtt < 0)
 313                 return;
 314
 315         spin_lock(&peer->rtt_input_lock);
 316
 317         /* Replace the oldest datum in the RTT buffer */
 318         sum -= peer->rtt_cache[cursor];
 319         sum += rtt;
 320         peer->rtt_cache[cursor] = rtt;
 321         peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1);
 322         peer->rtt_sum = sum;
 323         if (usage < RXRPC_RTT_CACHE_SIZE) {
 324                 usage++;
 325                 peer->rtt_usage = usage;
 326         }
 327
 328         spin_unlock(&peer->rtt_input_lock);
 329
 330         /* Now recalculate the average */
 331         if (usage == RXRPC_RTT_CACHE_SIZE) {
 332                 avg = sum / RXRPC_RTT_CACHE_SIZE;
 333         } else {
 334                 avg = sum;
 335                 do_div(avg, usage);
 336         }
 337
 338         /* Don't need to update this under lock */
 339         peer->rtt = avg;
 340         trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt,
 341                            usage, avg);
 342 }
 343
 344 /*
 345  * Perform keep-alive pings.
 346  */
 347 static void rxrpc_peer_keepalive_dispatch(struct rxrpc_net *rxnet,
 348                                           struct list_head *collector,
 349                                           time64_t base,
 350                                           u8 cursor)
 351 {
 352         struct rxrpc_peer *peer;
 353         const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1;
 354         time64_t keepalive_at;
 355         int slot;
 356
 357         spin_lock_bh(&rxnet->peer_hash_lock);
 358
 359         while (!list_empty(collector)) {
 360                 peer = list_entry(collector->next,
 361                                   struct rxrpc_peer, keepalive_link);
 362
 363                 list_del_init(&peer->keepalive_link);
 364                 if (!rxrpc_get_peer_maybe(peer))
 365                         continue;
 366
 367                 spin_unlock_bh(&rxnet->peer_hash_lock);
 368
 369                 keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME;
 370                 slot = keepalive_at - base;
 371                 _debug("%02x peer %u t=%d {%pISp}",
 372                        cursor, peer->debug_id, slot, &peer->srx.transport);
 373
 374                 if (keepalive_at <= base ||
 375                     keepalive_at > base + RXRPC_KEEPALIVE_TIME) {
 376                         rxrpc_send_keepalive(peer);
 377                         slot = RXRPC_KEEPALIVE_TIME;
 378                 }
 379
 380                 /* A transmission to this peer occurred since last we examined
 381                  * it so put it into the appropriate future bucket.
 382                  */
 383                 slot += cursor;
 384                 slot &= mask;
 385                 spin_lock_bh(&rxnet->peer_hash_lock);
 386                 list_add_tail(&peer->keepalive_link,
 387                               &rxnet->peer_keepalive[slot & mask]);
 388                 rxrpc_put_peer_locked(peer);
 389         }
 390
 391         spin_unlock_bh(&rxnet->peer_hash_lock);
 392 }
 393
 394 /*
 395  * Perform keep-alive pings with VERSION packets to keep any NAT alive.
 396  */
 397 void rxrpc_peer_keepalive_worker(struct work_struct *work)
 398 {
 399         struct rxrpc_net *rxnet =
 400                 container_of(work, struct rxrpc_net, peer_keepalive_work);
 401         const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1;
 402         time64_t base, now, delay;
 403         u8 cursor, stop;
 404         LIST_HEAD(collector);
 405
 406         now = ktime_get_seconds();
 407         base = rxnet->peer_keepalive_base;
 408         cursor = rxnet->peer_keepalive_cursor;
 409         _enter("%lld,%u", base - now, cursor);
 410
 411         if (!rxnet->live)
 412                 return;
 413
 414         /* Remove to a temporary list all the peers that are currently lodged
 415          * in expired buckets plus all new peers.
 416          *
 417          * Everything in the bucket at the cursor is processed this
 418          * second; the bucket at cursor + 1 goes at now + 1s and so
 419          * on...
 420          */
 421         spin_lock_bh(&rxnet->peer_hash_lock);
 422         list_splice_init(&rxnet->peer_keepalive_new, &collector);
 423
 424         stop = cursor + ARRAY_SIZE(rxnet->peer_keepalive);
 425         while (base <= now && (s8)(cursor - stop) < 0) {
 426                 list_splice_tail_init(&rxnet->peer_keepalive[cursor & mask],
 427                                       &collector);
 428                 base++;
 429                 cursor++;
 430         }
 431
 432         base = now;
 433         spin_unlock_bh(&rxnet->peer_hash_lock);
 434
 435         rxnet->peer_keepalive_base = base;
 436         rxnet->peer_keepalive_cursor = cursor;
 437         rxrpc_peer_keepalive_dispatch(rxnet, &collector, base, cursor);
 438         ASSERT(list_empty(&collector));
 439
 440         /* Schedule the timer for the next occupied timeslot. */
 441         cursor = rxnet->peer_keepalive_cursor;
 442         stop = cursor + RXRPC_KEEPALIVE_TIME - 1;
 443         for (; (s8)(cursor - stop) < 0; cursor++) {
 444                 if (!list_empty(&rxnet->peer_keepalive[cursor & mask]))
 445                         break;
 446                 base++;
 447         }
 448
 449         now = ktime_get_seconds();
 450         delay = base - now;
 451         if (delay < 1)
 452                 delay = 1;
 453         delay *= HZ;
 454         if (rxnet->live)
 455                 timer_reduce(&rxnet->peer_keepalive_timer, jiffies + delay);
 456
 457         _leave("");
 458 }