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
  27 /*
  28  * Find the peer associated with an ICMP packet.
  29  */
  30 static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local,
  31                                                      const struct sk_buff *skb,
  32                                                      struct sockaddr_rxrpc *srx)
  33 {
  34         struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
  35
  36         _enter("");
  37
  38         memset(srx, 0, sizeof(*srx));
  39         srx->transport_type = local->srx.transport_type;
  40         srx->transport_len = local->srx.transport_len;
  41         srx->transport.family = local->srx.transport.family;
  42
  43         /* Can we see an ICMP4 packet on an ICMP6 listening socket?  and vice
  44          * versa?
  45          */
  46         switch (srx->transport.family) {
  47         case 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                 srx->transport.sin6.sin6_port = serr->port;
  72                 switch (serr->ee.ee_origin) {
  73                 case SO_EE_ORIGIN_ICMP6:
  74                         _net("Rx ICMP6");
  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.sin6.sin6_addr.s6_addr32[0] = 0;
  82                         srx->transport.sin6.sin6_addr.s6_addr32[1] = 0;
  83                         srx->transport.sin6.sin6_addr.s6_addr32[2] = htonl(0xffff);
  84                         memcpy(srx->transport.sin6.sin6_addr.s6_addr + 12,
  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         skb = sock_dequeue_err_skb(sk);
 157         if (!skb) {
 158                 _leave("UDP socket errqueue empty");
 159                 return;
 160         }
 161         rxrpc_new_skb(skb, rxrpc_skb_rx_received);
 162         serr = SKB_EXT_ERR(skb);
 163         if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
 164                 _leave("UDP empty message");
 165                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 166                 return;
 167         }
 168
 169         rcu_read_lock();
 170         peer = rxrpc_lookup_peer_icmp_rcu(local, skb, &srx);
 171         if (peer && !rxrpc_get_peer_maybe(peer))
 172                 peer = NULL;
 173         if (!peer) {
 174                 rcu_read_unlock();
 175                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 176                 _leave(" [no peer]");
 177                 return;
 178         }
 179
 180         trace_rxrpc_rx_icmp(peer, &serr->ee, &srx);
 181
 182         if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
 183              serr->ee.ee_type == ICMP_DEST_UNREACH &&
 184              serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
 185                 rxrpc_adjust_mtu(peer, serr);
 186                 rcu_read_unlock();
 187                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 188                 rxrpc_put_peer(peer);
 189                 _leave(" [MTU update]");
 190                 return;
 191         }
 192
 193         rxrpc_store_error(peer, serr);
 194         rcu_read_unlock();
 195         rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 196
 197         /* The ref we obtained is passed off to the work item */
 198         __rxrpc_queue_peer_error(peer);
 199         _leave("");
 200 }
 201
 202 /*
 203  * Map an error report to error codes on the peer record.
 204  */
 205 static void rxrpc_store_error(struct rxrpc_peer *peer,
 206                               struct sock_exterr_skb *serr)
 207 {
 208         struct sock_extended_err *ee;
 209         int err;
 210
 211         _enter("");
 212
 213         ee = &serr->ee;
 214
 215         err = ee->ee_errno;
 216
 217         switch (ee->ee_origin) {
 218         case SO_EE_ORIGIN_ICMP:
 219                 switch (ee->ee_type) {
 220                 case ICMP_DEST_UNREACH:
 221                         switch (ee->ee_code) {
 222                         case ICMP_NET_UNREACH:
 223                                 _net("Rx Received ICMP Network Unreachable");
 224                                 break;
 225                         case ICMP_HOST_UNREACH:
 226                                 _net("Rx Received ICMP Host Unreachable");
 227                                 break;
 228                         case ICMP_PORT_UNREACH:
 229                                 _net("Rx Received ICMP Port Unreachable");
 230                                 break;
 231                         case ICMP_NET_UNKNOWN:
 232                                 _net("Rx Received ICMP Unknown Network");
 233                                 break;
 234                         case ICMP_HOST_UNKNOWN:
 235                                 _net("Rx Received ICMP Unknown Host");
 236                                 break;
 237                         default:
 238                                 _net("Rx Received ICMP DestUnreach code=%u",
 239                                      ee->ee_code);
 240                                 break;
 241                         }
 242                         break;
 243
 244                 case ICMP_TIME_EXCEEDED:
 245                         _net("Rx Received ICMP TTL Exceeded");
 246                         break;
 247
 248                 default:
 249                         _proto("Rx Received ICMP error { type=%u code=%u }",
 250                                ee->ee_type, ee->ee_code);
 251                         break;
 252                 }
 253                 break;
 254
 255         case SO_EE_ORIGIN_NONE:
 256         case SO_EE_ORIGIN_LOCAL:
 257                 _proto("Rx Received local error { error=%d }", err);
 258                 err += RXRPC_LOCAL_ERROR_OFFSET;
 259                 break;
 260
 261         case SO_EE_ORIGIN_ICMP6:
 262         default:
 263                 _proto("Rx Received error report { orig=%u }", ee->ee_origin);
 264                 break;
 265         }
 266
 267         peer->error_report = err;
 268 }
 269
 270 /*
 271  * Distribute an error that occurred on a peer
 272  */
 273 void rxrpc_peer_error_distributor(struct work_struct *work)
 274 {
 275         struct rxrpc_peer *peer =
 276                 container_of(work, struct rxrpc_peer, error_distributor);
 277         struct rxrpc_call *call;
 278         enum rxrpc_call_completion compl;
 279         int error;
 280
 281         _enter("");
 282
 283         error = READ_ONCE(peer->error_report);
 284         if (error < RXRPC_LOCAL_ERROR_OFFSET) {
 285                 compl = RXRPC_CALL_NETWORK_ERROR;
 286         } else {
 287                 compl = RXRPC_CALL_LOCAL_ERROR;
 288                 error -= RXRPC_LOCAL_ERROR_OFFSET;
 289         }
 290
 291         _debug("ISSUE ERROR %s %d", rxrpc_call_completions[compl], error);
 292
 293         spin_lock_bh(&peer->lock);
 294
 295         while (!hlist_empty(&peer->error_targets)) {
 296                 call = hlist_entry(peer->error_targets.first,
 297                                    struct rxrpc_call, error_link);
 298                 hlist_del_init(&call->error_link);
 299                 rxrpc_see_call(call);
 300
 301                 if (rxrpc_set_call_completion(call, compl, 0, -error))
 302                         rxrpc_notify_socket(call);
 303         }
 304
 305         spin_unlock_bh(&peer->lock);
 306
 307         rxrpc_put_peer(peer);
 308         _leave("");
 309 }
 310
 311 /*
 312  * Add RTT information to cache.  This is called in softirq mode and has
 313  * exclusive access to the peer RTT data.
 314  */
 315 void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
 316                         rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,
 317                         ktime_t send_time, ktime_t resp_time)
 318 {
 319         struct rxrpc_peer *peer = call->peer;
 320         s64 rtt;
 321         u64 sum = peer->rtt_sum, avg;
 322         u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage;
 323
 324         rtt = ktime_to_ns(ktime_sub(resp_time, send_time));
 325         if (rtt < 0)
 326                 return;
 327
 328         /* Replace the oldest datum in the RTT buffer */
 329         sum -= peer->rtt_cache[cursor];
 330         sum += rtt;
 331         peer->rtt_cache[cursor] = rtt;
 332         peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1);
 333         peer->rtt_sum = sum;
 334         if (usage < RXRPC_RTT_CACHE_SIZE) {
 335                 usage++;
 336                 peer->rtt_usage = usage;
 337         }
 338
 339         /* Now recalculate the average */
 340         if (usage == RXRPC_RTT_CACHE_SIZE) {
 341                 avg = sum / RXRPC_RTT_CACHE_SIZE;
 342         } else {
 343                 avg = sum;
 344                 do_div(avg, usage);
 345         }
 346
 347         peer->rtt = avg;
 348         trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt,
 349                            usage, avg);
 350 }
 351
 352 /*
 353  * Perform keep-alive pings with VERSION packets to keep any NAT alive.
 354  */
 355 void rxrpc_peer_keepalive_worker(struct work_struct *work)
 356 {
 357         struct rxrpc_net *rxnet =
 358                 container_of(work, struct rxrpc_net, peer_keepalive_work);
 359         struct rxrpc_peer *peer;
 360         unsigned long delay;
 361         ktime_t base, now = ktime_get_real();
 362         s64 diff;
 363         u8 cursor, slot;
 364
 365         base = rxnet->peer_keepalive_base;
 366         cursor = rxnet->peer_keepalive_cursor;
 367
 368         _enter("%u,%lld", cursor, ktime_sub(now, base));
 369
 370 next_bucket:
 371         diff = ktime_to_ns(ktime_sub(now, base));
 372         if (diff < 0)
 373                 goto resched;
 374
 375         _debug("at %u", cursor);
 376         spin_lock_bh(&rxnet->peer_hash_lock);
 377 next_peer:
 378         if (!rxnet->live) {
 379                 spin_unlock_bh(&rxnet->peer_hash_lock);
 380                 goto out;
 381         }
 382
 383         /* Everything in the bucket at the cursor is processed this second; the
 384          * bucket at cursor + 1 goes now + 1s and so on...
 385          */
 386         if (hlist_empty(&rxnet->peer_keepalive[cursor])) {
 387                 if (hlist_empty(&rxnet->peer_keepalive_new)) {
 388                         spin_unlock_bh(&rxnet->peer_hash_lock);
 389                         goto emptied_bucket;
 390                 }
 391
 392                 hlist_move_list(&rxnet->peer_keepalive_new,
 393                                 &rxnet->peer_keepalive[cursor]);
 394         }
 395
 396         peer = hlist_entry(rxnet->peer_keepalive[cursor].first,
 397                            struct rxrpc_peer, keepalive_link);
 398         hlist_del_init(&peer->keepalive_link);
 399         if (!rxrpc_get_peer_maybe(peer))
 400                 goto next_peer;
 401
 402         spin_unlock_bh(&rxnet->peer_hash_lock);
 403
 404         _debug("peer %u {%pISp}", peer->debug_id, &peer->srx.transport);
 405
 406 recalc:
 407         diff = ktime_divns(ktime_sub(peer->last_tx_at, base), NSEC_PER_SEC);
 408         if (diff < -30 || diff > 30)
 409                 goto send; /* LSW of 64-bit time probably wrapped on 32-bit */
 410         diff += RXRPC_KEEPALIVE_TIME - 1;
 411         if (diff < 0)
 412                 goto send;
 413
 414         slot = (diff > RXRPC_KEEPALIVE_TIME - 1) ? RXRPC_KEEPALIVE_TIME - 1 : diff;
 415         if (slot == 0)
 416                 goto send;
 417
 418         /* A transmission to this peer occurred since last we examined it so
 419          * put it into the appropriate future bucket.
 420          */
 421         slot = (slot + cursor) % ARRAY_SIZE(rxnet->peer_keepalive);
 422         spin_lock_bh(&rxnet->peer_hash_lock);
 423         hlist_add_head(&peer->keepalive_link, &rxnet->peer_keepalive[slot]);
 424         rxrpc_put_peer(peer);
 425         goto next_peer;
 426
 427 send:
 428         rxrpc_send_keepalive(peer);
 429         now = ktime_get_real();
 430         goto recalc;
 431
 432 emptied_bucket:
 433         cursor++;
 434         if (cursor >= ARRAY_SIZE(rxnet->peer_keepalive))
 435                 cursor = 0;
 436         base = ktime_add_ns(base, NSEC_PER_SEC);
 437         goto next_bucket;
 438
 439 resched:
 440         rxnet->peer_keepalive_base = base;
 441         rxnet->peer_keepalive_cursor = cursor;
 442         delay = nsecs_to_jiffies(-diff) + 1;
 443         timer_reduce(&rxnet->peer_keepalive_timer, jiffies + delay);
 444 out:
 445         _leave("");
 446 }