net/rxrpc/peer_event.c

   1 /* Peer event handling, typically ICMP messages.
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/net.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/errqueue.h>
  16 #include <linux/udp.h>
  17 #include <linux/in.h>
  18 #include <linux/in6.h>
  19 #include <linux/icmp.h>
  20 #include <net/sock.h>
  21 #include <net/af_rxrpc.h>
  22 #include <net/ip.h>
  23 #include "ar-internal.h"
  24
  25 static void rxrpc_store_error(struct rxrpc_peer *, struct sock_exterr_skb *);
  26 static void rxrpc_distribute_error(struct rxrpc_peer *, int,
  27                                    enum rxrpc_call_completion);
  28
  29 /*
  30  * Find the peer associated with an ICMP packet.
  31  */
  32 static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local,
  33                                                      const struct sk_buff *skb,
  34                                                      struct sockaddr_rxrpc *srx)
  35 {
  36         struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
  37
  38         _enter("");
  39
  40         memset(srx, 0, sizeof(*srx));
  41         srx->transport_type = local->srx.transport_type;
  42         srx->transport_len = local->srx.transport_len;
  43         srx->transport.family = local->srx.transport.family;
  44
  45         /* Can we see an ICMP4 packet on an ICMP6 listening socket?  and vice
  46          * versa?
  47          */
  48         switch (srx->transport.family) {
  49         case AF_INET:
  50                 srx->transport_len = sizeof(srx->transport.sin);
  51                 srx->transport.family = AF_INET;
  52                 srx->transport.sin.sin_port = serr->port;
  53                 switch (serr->ee.ee_origin) {
  54                 case SO_EE_ORIGIN_ICMP:
  55                         _net("Rx ICMP");
  56                         memcpy(&srx->transport.sin.sin_addr,
  57                                skb_network_header(skb) + serr->addr_offset,
  58                                sizeof(struct in_addr));
  59                         break;
  60                 case SO_EE_ORIGIN_ICMP6:
  61                         _net("Rx ICMP6 on v4 sock");
  62                         memcpy(&srx->transport.sin.sin_addr,
  63                                skb_network_header(skb) + serr->addr_offset + 12,
  64                                sizeof(struct in_addr));
  65                         break;
  66                 default:
  67                         memcpy(&srx->transport.sin.sin_addr, &ip_hdr(skb)->saddr,
  68                                sizeof(struct in_addr));
  69                         break;
  70                 }
  71                 break;
  72
  73 #ifdef CONFIG_AF_RXRPC_IPV6
  74         case AF_INET6:
  75                 switch (serr->ee.ee_origin) {
  76                 case SO_EE_ORIGIN_ICMP6:
  77                         _net("Rx ICMP6");
  78                         srx->transport.sin6.sin6_port = serr->port;
  79                         memcpy(&srx->transport.sin6.sin6_addr,
  80                                skb_network_header(skb) + serr->addr_offset,
  81                                sizeof(struct in6_addr));
  82                         break;
  83                 case SO_EE_ORIGIN_ICMP:
  84                         _net("Rx ICMP on v6 sock");
  85                         srx->transport_len = sizeof(srx->transport.sin);
  86                         srx->transport.family = AF_INET;
  87                         srx->transport.sin.sin_port = serr->port;
  88                         memcpy(&srx->transport.sin.sin_addr,
  89                                skb_network_header(skb) + serr->addr_offset,
  90                                sizeof(struct in_addr));
  91                         break;
  92                 default:
  93                         memcpy(&srx->transport.sin6.sin6_addr,
  94                                &ipv6_hdr(skb)->saddr,
  95                                sizeof(struct in6_addr));
  96                         break;
  97                 }
  98                 break;
  99 #endif
 100
 101         default:
 102                 BUG();
 103         }
 104
 105         return rxrpc_lookup_peer_rcu(local, srx);
 106 }
 107
 108 /*
 109  * Handle an MTU/fragmentation problem.
 110  */
 111 static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *serr)
 112 {
 113         u32 mtu = serr->ee.ee_info;
 114
 115         _net("Rx ICMP Fragmentation Needed (%d)", mtu);
 116
 117         /* wind down the local interface MTU */
 118         if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
 119                 peer->if_mtu = mtu;
 120                 _net("I/F MTU %u", mtu);
 121         }
 122
 123         if (mtu == 0) {
 124                 /* they didn't give us a size, estimate one */
 125                 mtu = peer->if_mtu;
 126                 if (mtu > 1500) {
 127                         mtu >>= 1;
 128                         if (mtu < 1500)
 129                                 mtu = 1500;
 130                 } else {
 131                         mtu -= 100;
 132                         if (mtu < peer->hdrsize)
 133                                 mtu = peer->hdrsize + 4;
 134                 }
 135         }
 136
 137         if (mtu < peer->mtu) {
 138                 spin_lock_bh(&peer->lock);
 139                 peer->mtu = mtu;
 140                 peer->maxdata = peer->mtu - peer->hdrsize;
 141                 spin_unlock_bh(&peer->lock);
 142                 _net("Net MTU %u (maxdata %u)",
 143                      peer->mtu, peer->maxdata);
 144         }
 145 }
 146
 147 /*
 148  * Handle an error received on the local endpoint.
 149  */
 150 void rxrpc_error_report(struct sock *sk)
 151 {
 152         struct sock_exterr_skb *serr;
 153         struct sockaddr_rxrpc srx;
 154         struct rxrpc_local *local = sk->sk_user_data;
 155         struct rxrpc_peer *peer;
 156         struct sk_buff *skb;
 157
 158         _enter("%p{%d}", sk, local->debug_id);
 159
 160         /* Clear the outstanding error value on the socket so that it doesn't
 161          * cause kernel_sendmsg() to return it later.
 162          */
 163         sock_error(sk);
 164
 165         skb = sock_dequeue_err_skb(sk);
 166         if (!skb) {
 167                 _leave("UDP socket errqueue empty");
 168                 return;
 169         }
 170         rxrpc_new_skb(skb, rxrpc_skb_rx_received);
 171         serr = SKB_EXT_ERR(skb);
 172         if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
 173                 _leave("UDP empty message");
 174                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 175                 return;
 176         }
 177
 178         rcu_read_lock();
 179         peer = rxrpc_lookup_peer_icmp_rcu(local, skb, &srx);
 180         if (peer && !rxrpc_get_peer_maybe(peer))
 181                 peer = NULL;
 182         if (!peer) {
 183                 rcu_read_unlock();
 184                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 185                 _leave(" [no peer]");
 186                 return;
 187         }
 188
 189         trace_rxrpc_rx_icmp(peer, &serr->ee, &srx);
 190
 191         if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
 192              serr->ee.ee_type == ICMP_DEST_UNREACH &&
 193              serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
 194                 rxrpc_adjust_mtu(peer, serr);
 195                 rcu_read_unlock();
 196                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 197                 rxrpc_put_peer(peer);
 198                 _leave(" [MTU update]");
 199                 return;
 200         }
 201
 202         rxrpc_store_error(peer, serr);
 203         rcu_read_unlock();
 204         rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 205         rxrpc_put_peer(peer);
 206
 207         _leave("");
 208 }
 209
 210 /*
 211  * Map an error report to error codes on the peer record.
 212  */
 213 static void rxrpc_store_error(struct rxrpc_peer *peer,
 214                               struct sock_exterr_skb *serr)
 215 {
 216         enum rxrpc_call_completion compl = RXRPC_CALL_NETWORK_ERROR;
 217         struct sock_extended_err *ee;
 218         int err;
 219
 220         _enter("");
 221
 222         ee = &serr->ee;
 223
 224         err = ee->ee_errno;
 225
 226         switch (ee->ee_origin) {
 227         case SO_EE_ORIGIN_ICMP:
 228                 switch (ee->ee_type) {
 229                 case ICMP_DEST_UNREACH:
 230                         switch (ee->ee_code) {
 231                         case ICMP_NET_UNREACH:
 232                                 _net("Rx Received ICMP Network Unreachable");
 233                                 break;
 234                         case ICMP_HOST_UNREACH:
 235                                 _net("Rx Received ICMP Host Unreachable");
 236                                 break;
 237                         case ICMP_PORT_UNREACH:
 238                                 _net("Rx Received ICMP Port Unreachable");
 239                                 break;
 240                         case ICMP_NET_UNKNOWN:
 241                                 _net("Rx Received ICMP Unknown Network");
 242                                 break;
 243                         case ICMP_HOST_UNKNOWN:
 244                                 _net("Rx Received ICMP Unknown Host");
 245                                 break;
 246                         default:
 247                                 _net("Rx Received ICMP DestUnreach code=%u",
 248                                      ee->ee_code);
 249                                 break;
 250                         }
 251                         break;
 252
 253                 case ICMP_TIME_EXCEEDED:
 254                         _net("Rx Received ICMP TTL Exceeded");
 255                         break;
 256
 257                 default:
 258                         _proto("Rx Received ICMP error { type=%u code=%u }",
 259                                ee->ee_type, ee->ee_code);
 260                         break;
 261                 }
 262                 break;
 263
 264         case SO_EE_ORIGIN_NONE:
 265         case SO_EE_ORIGIN_LOCAL:
 266                 _proto("Rx Received local error { error=%d }", err);
 267                 compl = RXRPC_CALL_LOCAL_ERROR;
 268                 break;
 269
 270         case SO_EE_ORIGIN_ICMP6:
 271         default:
 272                 _proto("Rx Received error report { orig=%u }", ee->ee_origin);
 273                 break;
 274         }
 275
 276         rxrpc_distribute_error(peer, err, compl);
 277 }
 278
 279 /*
 280  * Distribute an error that occurred on a peer.
 281  */
 282 static void rxrpc_distribute_error(struct rxrpc_peer *peer, int error,
 283                                    enum rxrpc_call_completion compl)
 284 {
 285         struct rxrpc_call *call;
 286
 287         hlist_for_each_entry_rcu(call, &peer->error_targets, error_link) {
 288                 rxrpc_see_call(call);
 289                 if (call->state < RXRPC_CALL_COMPLETE &&
 290                     rxrpc_set_call_completion(call, compl, 0, -error))
 291                         rxrpc_notify_socket(call);
 292         }
 293 }
 294
 295 /*
 296  * Add RTT information to cache.  This is called in softirq mode and has
 297  * exclusive access to the peer RTT data.
 298  */
 299 void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
 300                         rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,
 301                         ktime_t send_time, ktime_t resp_time)
 302 {
 303         struct rxrpc_peer *peer = call->peer;
 304         s64 rtt;
 305         u64 sum = peer->rtt_sum, avg;
 306         u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage;
 307
 308         rtt = ktime_to_ns(ktime_sub(resp_time, send_time));
 309         if (rtt < 0)
 310                 return;
 311
 312         spin_lock(&peer->rtt_input_lock);
 313
 314         /* Replace the oldest datum in the RTT buffer */
 315         sum -= peer->rtt_cache[cursor];
 316         sum += rtt;
 317         peer->rtt_cache[cursor] = rtt;
 318         peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1);
 319         peer->rtt_sum = sum;
 320         if (usage < RXRPC_RTT_CACHE_SIZE) {
 321                 usage++;
 322                 peer->rtt_usage = usage;
 323         }
 324
 325         spin_unlock(&peer->rtt_input_lock);
 326
 327         /* Now recalculate the average */
 328         if (usage == RXRPC_RTT_CACHE_SIZE) {
 329                 avg = sum / RXRPC_RTT_CACHE_SIZE;
 330         } else {
 331                 avg = sum;
 332                 do_div(avg, usage);
 333         }
 334
 335         /* Don't need to update this under lock */
 336         peer->rtt = avg;
 337         trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt,
 338                            usage, avg);
 339 }
 340
 341 /*
 342  * Perform keep-alive pings.
 343  */
 344 static void rxrpc_peer_keepalive_dispatch(struct rxrpc_net *rxnet,
 345                                           struct list_head *collector,
 346                                           time64_t base,
 347                                           u8 cursor)
 348 {
 349         struct rxrpc_peer *peer;
 350         const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1;
 351         time64_t keepalive_at;
 352         int slot;
 353
 354         spin_lock_bh(&rxnet->peer_hash_lock);
 355
 356         while (!list_empty(collector)) {
 357                 peer = list_entry(collector->next,
 358                                   struct rxrpc_peer, keepalive_link);
 359
 360                 list_del_init(&peer->keepalive_link);
 361                 if (!rxrpc_get_peer_maybe(peer))
 362                         continue;
 363
 364                 spin_unlock_bh(&rxnet->peer_hash_lock);
 365
 366                 keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME;
 367                 slot = keepalive_at - base;
 368                 _debug("%02x peer %u t=%d {%pISp}",
 369                        cursor, peer->debug_id, slot, &peer->srx.transport);
 370
 371                 if (keepalive_at <= base ||
 372                     keepalive_at > base + RXRPC_KEEPALIVE_TIME) {
 373                         rxrpc_send_keepalive(peer);
 374                         slot = RXRPC_KEEPALIVE_TIME;
 375                 }
 376
 377                 /* A transmission to this peer occurred since last we examined
 378                  * it so put it into the appropriate future bucket.
 379                  */
 380                 slot += cursor;
 381                 slot &= mask;
 382                 spin_lock_bh(&rxnet->peer_hash_lock);
 383                 list_add_tail(&peer->keepalive_link,
 384                               &rxnet->peer_keepalive[slot & mask]);
 385                 rxrpc_put_peer(peer);
 386         }
 387
 388         spin_unlock_bh(&rxnet->peer_hash_lock);
 389 }
 390
 391 /*
 392  * Perform keep-alive pings with VERSION packets to keep any NAT alive.
 393  */
 394 void rxrpc_peer_keepalive_worker(struct work_struct *work)
 395 {
 396         struct rxrpc_net *rxnet =
 397                 container_of(work, struct rxrpc_net, peer_keepalive_work);
 398         const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1;
 399         time64_t base, now, delay;
 400         u8 cursor, stop;
 401         LIST_HEAD(collector);
 402
 403         now = ktime_get_seconds();
 404         base = rxnet->peer_keepalive_base;
 405         cursor = rxnet->peer_keepalive_cursor;
 406         _enter("%lld,%u", base - now, cursor);
 407
 408         if (!rxnet->live)
 409                 return;
 410
 411         /* Remove to a temporary list all the peers that are currently lodged
 412          * in expired buckets plus all new peers.
 413          *
 414          * Everything in the bucket at the cursor is processed this
 415          * second; the bucket at cursor + 1 goes at now + 1s and so
 416          * on...
 417          */
 418         spin_lock_bh(&rxnet->peer_hash_lock);
 419         list_splice_init(&rxnet->peer_keepalive_new, &collector);
 420
 421         stop = cursor + ARRAY_SIZE(rxnet->peer_keepalive);
 422         while (base <= now && (s8)(cursor - stop) < 0) {
 423                 list_splice_tail_init(&rxnet->peer_keepalive[cursor & mask],
 424                                       &collector);
 425                 base++;
 426                 cursor++;
 427         }
 428
 429         base = now;
 430         spin_unlock_bh(&rxnet->peer_hash_lock);
 431
 432         rxnet->peer_keepalive_base = base;
 433         rxnet->peer_keepalive_cursor = cursor;
 434         rxrpc_peer_keepalive_dispatch(rxnet, &collector, base, cursor);
 435         ASSERT(list_empty(&collector));
 436
 437         /* Schedule the timer for the next occupied timeslot. */
 438         cursor = rxnet->peer_keepalive_cursor;
 439         stop = cursor + RXRPC_KEEPALIVE_TIME - 1;
 440         for (; (s8)(cursor - stop) < 0; cursor++) {
 441                 if (!list_empty(&rxnet->peer_keepalive[cursor & mask]))
 442                         break;
 443                 base++;
 444         }
 445
 446         now = ktime_get_seconds();
 447         delay = base - now;
 448         if (delay < 1)
 449                 delay = 1;
 450         delay *= HZ;
 451         if (rxnet->live)
 452                 timer_reduce(&rxnet->peer_keepalive_timer, jiffies + delay);
 453
 454         _leave("");
 455 }