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 = sk->sk_user_data;
 151         struct rxrpc_peer *peer;
 152         struct sk_buff *skb;
 153
 154         _enter("%p{%d}", sk, local->debug_id);
 155
 156         /* Clear the outstanding error value on the socket so that it doesn't
 157          * cause kernel_sendmsg() to return it later.
 158          */
 159         sock_error(sk);
 160
 161         skb = sock_dequeue_err_skb(sk);
 162         if (!skb) {
 163                 _leave("UDP socket errqueue empty");
 164                 return;
 165         }
 166         rxrpc_new_skb(skb, rxrpc_skb_received);
 167         serr = SKB_EXT_ERR(skb);
 168         if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
 169                 _leave("UDP empty message");
 170                 rxrpc_free_skb(skb, rxrpc_skb_freed);
 171                 return;
 172         }
 173
 174         rcu_read_lock();
 175         peer = rxrpc_lookup_peer_icmp_rcu(local, skb, &srx);
 176         if (peer && !rxrpc_get_peer_maybe(peer))
 177                 peer = NULL;
 178         if (!peer) {
 179                 rcu_read_unlock();
 180                 rxrpc_free_skb(skb, rxrpc_skb_freed);
 181                 _leave(" [no peer]");
 182                 return;
 183         }
 184
 185         trace_rxrpc_rx_icmp(peer, &serr->ee, &srx);
 186
 187         if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
 188              serr->ee.ee_type == ICMP_DEST_UNREACH &&
 189              serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
 190                 rxrpc_adjust_mtu(peer, serr);
 191                 rcu_read_unlock();
 192                 rxrpc_free_skb(skb, rxrpc_skb_freed);
 193                 rxrpc_put_peer(peer);
 194                 _leave(" [MTU update]");
 195                 return;
 196         }
 197
 198         rxrpc_store_error(peer, serr);
 199         rcu_read_unlock();
 200         rxrpc_free_skb(skb, rxrpc_skb_freed);
 201         rxrpc_put_peer(peer);
 202
 203         _leave("");
 204 }
 205
 206 /*
 207  * Map an error report to error codes on the peer record.
 208  */
 209 static void rxrpc_store_error(struct rxrpc_peer *peer,
 210                               struct sock_exterr_skb *serr)
 211 {
 212         enum rxrpc_call_completion compl = RXRPC_CALL_NETWORK_ERROR;
 213         struct sock_extended_err *ee;
 214         int err;
 215
 216         _enter("");
 217
 218         ee = &serr->ee;
 219
 220         err = ee->ee_errno;
 221
 222         switch (ee->ee_origin) {
 223         case SO_EE_ORIGIN_ICMP:
 224                 switch (ee->ee_type) {
 225                 case ICMP_DEST_UNREACH:
 226                         switch (ee->ee_code) {
 227                         case ICMP_NET_UNREACH:
 228                                 _net("Rx Received ICMP Network Unreachable");
 229                                 break;
 230                         case ICMP_HOST_UNREACH:
 231                                 _net("Rx Received ICMP Host Unreachable");
 232                                 break;
 233                         case ICMP_PORT_UNREACH:
 234                                 _net("Rx Received ICMP Port Unreachable");
 235                                 break;
 236                         case ICMP_NET_UNKNOWN:
 237                                 _net("Rx Received ICMP Unknown Network");
 238                                 break;
 239                         case ICMP_HOST_UNKNOWN:
 240                                 _net("Rx Received ICMP Unknown Host");
 241                                 break;
 242                         default:
 243                                 _net("Rx Received ICMP DestUnreach code=%u",
 244                                      ee->ee_code);
 245                                 break;
 246                         }
 247                         break;
 248
 249                 case ICMP_TIME_EXCEEDED:
 250                         _net("Rx Received ICMP TTL Exceeded");
 251                         break;
 252
 253                 default:
 254                         _proto("Rx Received ICMP error { type=%u code=%u }",
 255                                ee->ee_type, ee->ee_code);
 256                         break;
 257                 }
 258                 break;
 259
 260         case SO_EE_ORIGIN_NONE:
 261         case SO_EE_ORIGIN_LOCAL:
 262                 _proto("Rx Received local error { error=%d }", err);
 263                 compl = RXRPC_CALL_LOCAL_ERROR;
 264                 break;
 265
 266         case SO_EE_ORIGIN_ICMP6:
 267         default:
 268                 _proto("Rx Received error report { orig=%u }", ee->ee_origin);
 269                 break;
 270         }
 271
 272         rxrpc_distribute_error(peer, err, compl);
 273 }
 274
 275 /*
 276  * Distribute an error that occurred on a peer.
 277  */
 278 static void rxrpc_distribute_error(struct rxrpc_peer *peer, int error,
 279                                    enum rxrpc_call_completion compl)
 280 {
 281         struct rxrpc_call *call;
 282
 283         hlist_for_each_entry_rcu(call, &peer->error_targets, error_link) {
 284                 rxrpc_see_call(call);
 285                 if (call->state < RXRPC_CALL_COMPLETE &&
 286                     rxrpc_set_call_completion(call, compl, 0, -error))
 287                         rxrpc_notify_socket(call);
 288         }
 289 }
 290
 291 /*
 292  * Add RTT information to cache.  This is called in softirq mode and has
 293  * exclusive access to the peer RTT data.
 294  */
 295 void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
 296                         rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,
 297                         ktime_t send_time, ktime_t resp_time)
 298 {
 299         struct rxrpc_peer *peer = call->peer;
 300         s64 rtt;
 301         u64 sum = peer->rtt_sum, avg;
 302         u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage;
 303
 304         rtt = ktime_to_ns(ktime_sub(resp_time, send_time));
 305         if (rtt < 0)
 306                 return;
 307
 308         spin_lock(&peer->rtt_input_lock);
 309
 310         /* Replace the oldest datum in the RTT buffer */
 311         sum -= peer->rtt_cache[cursor];
 312         sum += rtt;
 313         peer->rtt_cache[cursor] = rtt;
 314         peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1);
 315         peer->rtt_sum = sum;
 316         if (usage < RXRPC_RTT_CACHE_SIZE) {
 317                 usage++;
 318                 peer->rtt_usage = usage;
 319         }
 320
 321         spin_unlock(&peer->rtt_input_lock);
 322
 323         /* Now recalculate the average */
 324         if (usage == RXRPC_RTT_CACHE_SIZE) {
 325                 avg = sum / RXRPC_RTT_CACHE_SIZE;
 326         } else {
 327                 avg = sum;
 328                 do_div(avg, usage);
 329         }
 330
 331         /* Don't need to update this under lock */
 332         peer->rtt = avg;
 333         trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt,
 334                            usage, avg);
 335 }
 336
 337 /*
 338  * Perform keep-alive pings.
 339  */
 340 static void rxrpc_peer_keepalive_dispatch(struct rxrpc_net *rxnet,
 341                                           struct list_head *collector,
 342                                           time64_t base,
 343                                           u8 cursor)
 344 {
 345         struct rxrpc_peer *peer;
 346         const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1;
 347         time64_t keepalive_at;
 348         int slot;
 349
 350         spin_lock_bh(&rxnet->peer_hash_lock);
 351
 352         while (!list_empty(collector)) {
 353                 peer = list_entry(collector->next,
 354                                   struct rxrpc_peer, keepalive_link);
 355
 356                 list_del_init(&peer->keepalive_link);
 357                 if (!rxrpc_get_peer_maybe(peer))
 358                         continue;
 359
 360                 spin_unlock_bh(&rxnet->peer_hash_lock);
 361
 362                 keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME;
 363                 slot = keepalive_at - base;
 364                 _debug("%02x peer %u t=%d {%pISp}",
 365                        cursor, peer->debug_id, slot, &peer->srx.transport);
 366
 367                 if (keepalive_at <= base ||
 368                     keepalive_at > base + RXRPC_KEEPALIVE_TIME) {
 369                         rxrpc_send_keepalive(peer);
 370                         slot = RXRPC_KEEPALIVE_TIME;
 371                 }
 372
 373                 /* A transmission to this peer occurred since last we examined
 374                  * it so put it into the appropriate future bucket.
 375                  */
 376                 slot += cursor;
 377                 slot &= mask;
 378                 spin_lock_bh(&rxnet->peer_hash_lock);
 379                 list_add_tail(&peer->keepalive_link,
 380                               &rxnet->peer_keepalive[slot & mask]);
 381                 rxrpc_put_peer_locked(peer);
 382         }
 383
 384         spin_unlock_bh(&rxnet->peer_hash_lock);
 385 }
 386
 387 /*
 388  * Perform keep-alive pings with VERSION packets to keep any NAT alive.
 389  */
 390 void rxrpc_peer_keepalive_worker(struct work_struct *work)
 391 {
 392         struct rxrpc_net *rxnet =
 393                 container_of(work, struct rxrpc_net, peer_keepalive_work);
 394         const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1;
 395         time64_t base, now, delay;
 396         u8 cursor, stop;
 397         LIST_HEAD(collector);
 398
 399         now = ktime_get_seconds();
 400         base = rxnet->peer_keepalive_base;
 401         cursor = rxnet->peer_keepalive_cursor;
 402         _enter("%lld,%u", base - now, cursor);
 403
 404         if (!rxnet->live)
 405                 return;
 406
 407         /* Remove to a temporary list all the peers that are currently lodged
 408          * in expired buckets plus all new peers.
 409          *
 410          * Everything in the bucket at the cursor is processed this
 411          * second; the bucket at cursor + 1 goes at now + 1s and so
 412          * on...
 413          */
 414         spin_lock_bh(&rxnet->peer_hash_lock);
 415         list_splice_init(&rxnet->peer_keepalive_new, &collector);
 416
 417         stop = cursor + ARRAY_SIZE(rxnet->peer_keepalive);
 418         while (base <= now && (s8)(cursor - stop) < 0) {
 419                 list_splice_tail_init(&rxnet->peer_keepalive[cursor & mask],
 420                                       &collector);
 421                 base++;
 422                 cursor++;
 423         }
 424
 425         base = now;
 426         spin_unlock_bh(&rxnet->peer_hash_lock);
 427
 428         rxnet->peer_keepalive_base = base;
 429         rxnet->peer_keepalive_cursor = cursor;
 430         rxrpc_peer_keepalive_dispatch(rxnet, &collector, base, cursor);
 431         ASSERT(list_empty(&collector));
 432
 433         /* Schedule the timer for the next occupied timeslot. */
 434         cursor = rxnet->peer_keepalive_cursor;
 435         stop = cursor + RXRPC_KEEPALIVE_TIME - 1;
 436         for (; (s8)(cursor - stop) < 0; cursor++) {
 437                 if (!list_empty(&rxnet->peer_keepalive[cursor & mask]))
 438                         break;
 439                 base++;
 440         }
 441
 442         now = ktime_get_seconds();
 443         delay = base - now;
 444         if (delay < 1)
 445                 delay = 1;
 446         delay *= HZ;
 447         if (rxnet->live)
 448                 timer_reduce(&rxnet->peer_keepalive_timer, jiffies + delay);
 449
 450         _leave("");
 451 }