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