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.family = local->srx.transport.family;
  41
  42         /* Can we see an ICMP4 packet on an ICMP6 listening socket?  and vice
  43          * versa?
  44          */
  45         switch (srx.transport.family) {
  46         case AF_INET:
  47                 srx.transport.sin.sin_port = serr->port;
  48                 srx.transport_len = sizeof(struct sockaddr_in);
  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                 srx.transport_len = sizeof(struct sockaddr_in6);
  73                 switch (serr->ee.ee_origin) {
  74                 case SO_EE_ORIGIN_ICMP6:
  75                         _net("Rx ICMP6");
  76                         memcpy(&srx.transport.sin6.sin6_addr,
  77                                skb_network_header(skb) + serr->addr_offset,
  78                                sizeof(struct in6_addr));
  79                         break;
  80                 case SO_EE_ORIGIN_ICMP:
  81                         _net("Rx ICMP on v6 sock");
  82                         memcpy(srx.transport.sin6.sin6_addr.s6_addr + 12,
  83                                skb_network_header(skb) + serr->addr_offset,
  84                                sizeof(struct in_addr));
  85                         break;
  86                 default:
  87                         memcpy(&srx.transport.sin6.sin6_addr,
  88                                &ipv6_hdr(skb)->saddr,
  89                                sizeof(struct in6_addr));
  90                         break;
  91                 }
  92                 break;
  93 #endif
  94
  95         default:
  96                 BUG();
  97         }
  98
  99         return rxrpc_lookup_peer_rcu(local, &srx);
 100 }
 101
 102 /*
 103  * Handle an MTU/fragmentation problem.
 104  */
 105 static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *serr)
 106 {
 107         u32 mtu = serr->ee.ee_info;
 108
 109         _net("Rx ICMP Fragmentation Needed (%d)", mtu);
 110
 111         /* wind down the local interface MTU */
 112         if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
 113                 peer->if_mtu = mtu;
 114                 _net("I/F MTU %u", mtu);
 115         }
 116
 117         if (mtu == 0) {
 118                 /* they didn't give us a size, estimate one */
 119                 mtu = peer->if_mtu;
 120                 if (mtu > 1500) {
 121                         mtu >>= 1;
 122                         if (mtu < 1500)
 123                                 mtu = 1500;
 124                 } else {
 125                         mtu -= 100;
 126                         if (mtu < peer->hdrsize)
 127                                 mtu = peer->hdrsize + 4;
 128                 }
 129         }
 130
 131         if (mtu < peer->mtu) {
 132                 spin_lock_bh(&peer->lock);
 133                 peer->mtu = mtu;
 134                 peer->maxdata = peer->mtu - peer->hdrsize;
 135                 spin_unlock_bh(&peer->lock);
 136                 _net("Net MTU %u (maxdata %u)",
 137                      peer->mtu, peer->maxdata);
 138         }
 139 }
 140
 141 /*
 142  * Handle an error received on the local endpoint.
 143  */
 144 void rxrpc_error_report(struct sock *sk)
 145 {
 146         struct sock_exterr_skb *serr;
 147         struct rxrpc_local *local = sk->sk_user_data;
 148         struct rxrpc_peer *peer;
 149         struct sk_buff *skb;
 150
 151         _enter("%p{%d}", sk, local->debug_id);
 152
 153         skb = sock_dequeue_err_skb(sk);
 154         if (!skb) {
 155                 _leave("UDP socket errqueue empty");
 156                 return;
 157         }
 158         rxrpc_new_skb(skb, rxrpc_skb_rx_received);
 159         serr = SKB_EXT_ERR(skb);
 160         if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
 161                 _leave("UDP empty message");
 162                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 163                 return;
 164         }
 165
 166         rcu_read_lock();
 167         peer = rxrpc_lookup_peer_icmp_rcu(local, skb);
 168         if (peer && !rxrpc_get_peer_maybe(peer))
 169                 peer = NULL;
 170         if (!peer) {
 171                 rcu_read_unlock();
 172                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 173                 _leave(" [no peer]");
 174                 return;
 175         }
 176
 177         if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
 178              serr->ee.ee_type == ICMP_DEST_UNREACH &&
 179              serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
 180                 rxrpc_adjust_mtu(peer, serr);
 181                 rcu_read_unlock();
 182                 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 183                 rxrpc_put_peer(peer);
 184                 _leave(" [MTU update]");
 185                 return;
 186         }
 187
 188         rxrpc_store_error(peer, serr);
 189         rcu_read_unlock();
 190         rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 191
 192         /* The ref we obtained is passed off to the work item */
 193         rxrpc_queue_work(&peer->error_distributor);
 194         _leave("");
 195 }
 196
 197 /*
 198  * Map an error report to error codes on the peer record.
 199  */
 200 static void rxrpc_store_error(struct rxrpc_peer *peer,
 201                               struct sock_exterr_skb *serr)
 202 {
 203         struct sock_extended_err *ee;
 204         int err;
 205
 206         _enter("");
 207
 208         ee = &serr->ee;
 209
 210         _net("Rx Error o=%d t=%d c=%d e=%d",
 211              ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
 212
 213         err = ee->ee_errno;
 214
 215         switch (ee->ee_origin) {
 216         case SO_EE_ORIGIN_ICMP:
 217                 switch (ee->ee_type) {
 218                 case ICMP_DEST_UNREACH:
 219                         switch (ee->ee_code) {
 220                         case ICMP_NET_UNREACH:
 221                                 _net("Rx Received ICMP Network Unreachable");
 222                                 break;
 223                         case ICMP_HOST_UNREACH:
 224                                 _net("Rx Received ICMP Host Unreachable");
 225                                 break;
 226                         case ICMP_PORT_UNREACH:
 227                                 _net("Rx Received ICMP Port Unreachable");
 228                                 break;
 229                         case ICMP_NET_UNKNOWN:
 230                                 _net("Rx Received ICMP Unknown Network");
 231                                 break;
 232                         case ICMP_HOST_UNKNOWN:
 233                                 _net("Rx Received ICMP Unknown Host");
 234                                 break;
 235                         default:
 236                                 _net("Rx Received ICMP DestUnreach code=%u",
 237                                      ee->ee_code);
 238                                 break;
 239                         }
 240                         break;
 241
 242                 case ICMP_TIME_EXCEEDED:
 243                         _net("Rx Received ICMP TTL Exceeded");
 244                         break;
 245
 246                 default:
 247                         _proto("Rx Received ICMP error { type=%u code=%u }",
 248                                ee->ee_type, ee->ee_code);
 249                         break;
 250                 }
 251                 break;
 252
 253         case SO_EE_ORIGIN_NONE:
 254         case SO_EE_ORIGIN_LOCAL:
 255                 _proto("Rx Received local error { error=%d }", err);
 256                 err += RXRPC_LOCAL_ERROR_OFFSET;
 257                 break;
 258
 259         case SO_EE_ORIGIN_ICMP6:
 260         default:
 261                 _proto("Rx Received error report { orig=%u }", ee->ee_origin);
 262                 break;
 263         }
 264
 265         peer->error_report = err;
 266 }
 267
 268 /*
 269  * Distribute an error that occurred on a peer
 270  */
 271 void rxrpc_peer_error_distributor(struct work_struct *work)
 272 {
 273         struct rxrpc_peer *peer =
 274                 container_of(work, struct rxrpc_peer, error_distributor);
 275         struct rxrpc_call *call;
 276         enum rxrpc_call_completion compl;
 277         int error;
 278
 279         _enter("");
 280
 281         error = READ_ONCE(peer->error_report);
 282         if (error < RXRPC_LOCAL_ERROR_OFFSET) {
 283                 compl = RXRPC_CALL_NETWORK_ERROR;
 284         } else {
 285                 compl = RXRPC_CALL_LOCAL_ERROR;
 286                 error -= RXRPC_LOCAL_ERROR_OFFSET;
 287         }
 288
 289         _debug("ISSUE ERROR %s %d", rxrpc_call_completions[compl], error);
 290
 291         spin_lock_bh(&peer->lock);
 292
 293         while (!hlist_empty(&peer->error_targets)) {
 294                 call = hlist_entry(peer->error_targets.first,
 295                                    struct rxrpc_call, error_link);
 296                 hlist_del_init(&call->error_link);
 297                 rxrpc_see_call(call);
 298
 299                 if (rxrpc_set_call_completion(call, compl, 0, -error))
 300                         rxrpc_notify_socket(call);
 301         }
 302
 303         spin_unlock_bh(&peer->lock);
 304
 305         rxrpc_put_peer(peer);
 306         _leave("");
 307 }
 308
 309 /*
 310  * Add RTT information to cache.  This is called in softirq mode and has
 311  * exclusive access to the peer RTT data.
 312  */
 313 void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
 314                         rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,
 315                         ktime_t send_time, ktime_t resp_time)
 316 {
 317         struct rxrpc_peer *peer = call->peer;
 318         s64 rtt;
 319         u64 sum = peer->rtt_sum, avg;
 320         u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage;
 321
 322         rtt = ktime_to_ns(ktime_sub(resp_time, send_time));
 323         if (rtt < 0)
 324                 return;
 325
 326         /* Replace the oldest datum in the RTT buffer */
 327         sum -= peer->rtt_cache[cursor];
 328         sum += rtt;
 329         peer->rtt_cache[cursor] = rtt;
 330         peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1);
 331         peer->rtt_sum = sum;
 332         if (usage < RXRPC_RTT_CACHE_SIZE) {
 333                 usage++;
 334                 peer->rtt_usage = usage;
 335         }
 336
 337         /* Now recalculate the average */
 338         if (usage == RXRPC_RTT_CACHE_SIZE) {
 339                 avg = sum / RXRPC_RTT_CACHE_SIZE;
 340         } else {
 341                 avg = sum;
 342                 do_div(avg, usage);
 343         }
 344
 345         peer->rtt = avg;
 346         trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt,
 347                            usage, avg);
 348 }