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 {
  33         struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
  34         struct sockaddr_rxrpc srx;
  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 rxrpc_local *local = sk->sk_user_data;
 150         struct rxrpc_peer *peer;
 151         struct sk_buff *skb;
 152
 153         if (unlikely(!local))
 154                 return;
 155
 156         _enter("%p{%d}", sk, local->debug_id);
 157
 158         skb = sock_dequeue_err_skb(sk);
 159         if (!skb) {
 160                 _leave("UDP socket errqueue empty");
 161                 return;
 162         }
 163         rxrpc_new_skb(skb, rxrpc_skb_rx_received);
 164         serr = SKB_EXT_ERR(skb);
 165         if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
 166                 _leave("UDP empty message");
 167                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 168                 return;
 169         }
 170
 171         rcu_read_lock();
 172         peer = rxrpc_lookup_peer_icmp_rcu(local, skb);
 173         if (peer && !rxrpc_get_peer_maybe(peer))
 174                 peer = NULL;
 175         if (!peer) {
 176                 rcu_read_unlock();
 177                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 178                 _leave(" [no peer]");
 179                 return;
 180         }
 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_work(&peer->error_distributor);
 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         _net("Rx Error o=%d t=%d c=%d e=%d",
 216              ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
 217
 218         err = ee->ee_errno;
 219
 220         switch (ee->ee_origin) {
 221         case SO_EE_ORIGIN_ICMP:
 222                 switch (ee->ee_type) {
 223                 case ICMP_DEST_UNREACH:
 224                         switch (ee->ee_code) {
 225                         case ICMP_NET_UNREACH:
 226                                 _net("Rx Received ICMP Network Unreachable");
 227                                 break;
 228                         case ICMP_HOST_UNREACH:
 229                                 _net("Rx Received ICMP Host Unreachable");
 230                                 break;
 231                         case ICMP_PORT_UNREACH:
 232                                 _net("Rx Received ICMP Port Unreachable");
 233                                 break;
 234                         case ICMP_NET_UNKNOWN:
 235                                 _net("Rx Received ICMP Unknown Network");
 236                                 break;
 237                         case ICMP_HOST_UNKNOWN:
 238                                 _net("Rx Received ICMP Unknown Host");
 239                                 break;
 240                         default:
 241                                 _net("Rx Received ICMP DestUnreach code=%u",
 242                                      ee->ee_code);
 243                                 break;
 244                         }
 245                         break;
 246
 247                 case ICMP_TIME_EXCEEDED:
 248                         _net("Rx Received ICMP TTL Exceeded");
 249                         break;
 250
 251                 default:
 252                         _proto("Rx Received ICMP error { type=%u code=%u }",
 253                                ee->ee_type, ee->ee_code);
 254                         break;
 255                 }
 256                 break;
 257
 258         case SO_EE_ORIGIN_NONE:
 259         case SO_EE_ORIGIN_LOCAL:
 260                 _proto("Rx Received local error { error=%d }", err);
 261                 err += RXRPC_LOCAL_ERROR_OFFSET;
 262                 break;
 263
 264         case SO_EE_ORIGIN_ICMP6:
 265         default:
 266                 _proto("Rx Received error report { orig=%u }", ee->ee_origin);
 267                 break;
 268         }
 269
 270         peer->error_report = err;
 271 }
 272
 273 /*
 274  * Distribute an error that occurred on a peer
 275  */
 276 void rxrpc_peer_error_distributor(struct work_struct *work)
 277 {
 278         struct rxrpc_peer *peer =
 279                 container_of(work, struct rxrpc_peer, error_distributor);
 280         struct rxrpc_call *call;
 281         enum rxrpc_call_completion compl;
 282         int error;
 283
 284         _enter("");
 285
 286         error = READ_ONCE(peer->error_report);
 287         if (error < RXRPC_LOCAL_ERROR_OFFSET) {
 288                 compl = RXRPC_CALL_NETWORK_ERROR;
 289         } else {
 290                 compl = RXRPC_CALL_LOCAL_ERROR;
 291                 error -= RXRPC_LOCAL_ERROR_OFFSET;
 292         }
 293
 294         _debug("ISSUE ERROR %s %d", rxrpc_call_completions[compl], error);
 295
 296         spin_lock_bh(&peer->lock);
 297
 298         while (!hlist_empty(&peer->error_targets)) {
 299                 call = hlist_entry(peer->error_targets.first,
 300                                    struct rxrpc_call, error_link);
 301                 hlist_del_init(&call->error_link);
 302                 rxrpc_see_call(call);
 303
 304                 if (rxrpc_set_call_completion(call, compl, 0, -error))
 305                         rxrpc_notify_socket(call);
 306         }
 307
 308         spin_unlock_bh(&peer->lock);
 309
 310         rxrpc_put_peer(peer);
 311         _leave("");
 312 }
 313
 314 /*
 315  * Add RTT information to cache.  This is called in softirq mode and has
 316  * exclusive access to the peer RTT data.
 317  */
 318 void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
 319                         rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,
 320                         ktime_t send_time, ktime_t resp_time)
 321 {
 322         struct rxrpc_peer *peer = call->peer;
 323         s64 rtt;
 324         u64 sum = peer->rtt_sum, avg;
 325         u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage;
 326
 327         rtt = ktime_to_ns(ktime_sub(resp_time, send_time));
 328         if (rtt < 0)
 329                 return;
 330
 331         /* Replace the oldest datum in the RTT buffer */
 332         sum -= peer->rtt_cache[cursor];
 333         sum += rtt;
 334         peer->rtt_cache[cursor] = rtt;
 335         peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1);
 336         peer->rtt_sum = sum;
 337         if (usage < RXRPC_RTT_CACHE_SIZE) {
 338                 usage++;
 339                 peer->rtt_usage = usage;
 340         }
 341
 342         /* Now recalculate the average */
 343         if (usage == RXRPC_RTT_CACHE_SIZE) {
 344                 avg = sum / RXRPC_RTT_CACHE_SIZE;
 345         } else {
 346                 avg = sum;
 347                 do_div(avg, usage);
 348         }
 349
 350         peer->rtt = avg;
 351         trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt,
 352                            usage, avg);
 353 }