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         default:
  70                 BUG();
  71         }
  72
  73         return rxrpc_lookup_peer_rcu(local, &srx);
  74 }
  75
  76 /*
  77  * Handle an MTU/fragmentation problem.
  78  */
  79 static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *serr)
  80 {
  81         u32 mtu = serr->ee.ee_info;
  82
  83         _net("Rx ICMP Fragmentation Needed (%d)", mtu);
  84
  85         /* wind down the local interface MTU */
  86         if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
  87                 peer->if_mtu = mtu;
  88                 _net("I/F MTU %u", mtu);
  89         }
  90
  91         if (mtu == 0) {
  92                 /* they didn't give us a size, estimate one */
  93                 mtu = peer->if_mtu;
  94                 if (mtu > 1500) {
  95                         mtu >>= 1;
  96                         if (mtu < 1500)
  97                                 mtu = 1500;
  98                 } else {
  99                         mtu -= 100;
 100                         if (mtu < peer->hdrsize)
 101                                 mtu = peer->hdrsize + 4;
 102                 }
 103         }
 104
 105         if (mtu < peer->mtu) {
 106                 spin_lock_bh(&peer->lock);
 107                 peer->mtu = mtu;
 108                 peer->maxdata = peer->mtu - peer->hdrsize;
 109                 spin_unlock_bh(&peer->lock);
 110                 _net("Net MTU %u (maxdata %u)",
 111                      peer->mtu, peer->maxdata);
 112         }
 113 }
 114
 115 /*
 116  * Handle an error received on the local endpoint.
 117  */
 118 void rxrpc_error_report(struct sock *sk)
 119 {
 120         struct sock_exterr_skb *serr;
 121         struct rxrpc_local *local = sk->sk_user_data;
 122         struct rxrpc_peer *peer;
 123         struct sk_buff *skb;
 124
 125         _enter("%p{%d}", sk, local->debug_id);
 126
 127         skb = sock_dequeue_err_skb(sk);
 128         if (!skb) {
 129                 _leave("UDP socket errqueue empty");
 130                 return;
 131         }
 132         serr = SKB_EXT_ERR(skb);
 133         if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
 134                 _leave("UDP empty message");
 135                 kfree_skb(skb);
 136                 return;
 137         }
 138
 139         rxrpc_new_skb(skb);
 140
 141         rcu_read_lock();
 142         peer = rxrpc_lookup_peer_icmp_rcu(local, skb);
 143         if (peer && !rxrpc_get_peer_maybe(peer))
 144                 peer = NULL;
 145         if (!peer) {
 146                 rcu_read_unlock();
 147                 rxrpc_free_skb(skb);
 148                 _leave(" [no peer]");
 149                 return;
 150         }
 151
 152         if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
 153              serr->ee.ee_type == ICMP_DEST_UNREACH &&
 154              serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
 155                 rxrpc_adjust_mtu(peer, serr);
 156                 rcu_read_unlock();
 157                 rxrpc_free_skb(skb);
 158                 rxrpc_put_peer(peer);
 159                 _leave(" [MTU update]");
 160                 return;
 161         }
 162
 163         rxrpc_store_error(peer, serr);
 164         rcu_read_unlock();
 165         rxrpc_free_skb(skb);
 166
 167         /* The ref we obtained is passed off to the work item */
 168         rxrpc_queue_work(&peer->error_distributor);
 169         _leave("");
 170 }
 171
 172 /*
 173  * Map an error report to error codes on the peer record.
 174  */
 175 static void rxrpc_store_error(struct rxrpc_peer *peer,
 176                               struct sock_exterr_skb *serr)
 177 {
 178         struct sock_extended_err *ee;
 179         int err;
 180
 181         _enter("");
 182
 183         ee = &serr->ee;
 184
 185         _net("Rx Error o=%d t=%d c=%d e=%d",
 186              ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
 187
 188         err = ee->ee_errno;
 189
 190         switch (ee->ee_origin) {
 191         case SO_EE_ORIGIN_ICMP:
 192                 switch (ee->ee_type) {
 193                 case ICMP_DEST_UNREACH:
 194                         switch (ee->ee_code) {
 195                         case ICMP_NET_UNREACH:
 196                                 _net("Rx Received ICMP Network Unreachable");
 197                                 break;
 198                         case ICMP_HOST_UNREACH:
 199                                 _net("Rx Received ICMP Host Unreachable");
 200                                 break;
 201                         case ICMP_PORT_UNREACH:
 202                                 _net("Rx Received ICMP Port Unreachable");
 203                                 break;
 204                         case ICMP_NET_UNKNOWN:
 205                                 _net("Rx Received ICMP Unknown Network");
 206                                 break;
 207                         case ICMP_HOST_UNKNOWN:
 208                                 _net("Rx Received ICMP Unknown Host");
 209                                 break;
 210                         default:
 211                                 _net("Rx Received ICMP DestUnreach code=%u",
 212                                      ee->ee_code);
 213                                 break;
 214                         }
 215                         break;
 216
 217                 case ICMP_TIME_EXCEEDED:
 218                         _net("Rx Received ICMP TTL Exceeded");
 219                         break;
 220
 221                 default:
 222                         _proto("Rx Received ICMP error { type=%u code=%u }",
 223                                ee->ee_type, ee->ee_code);
 224                         break;
 225                 }
 226                 break;
 227
 228         case SO_EE_ORIGIN_NONE:
 229         case SO_EE_ORIGIN_LOCAL:
 230                 _proto("Rx Received local error { error=%d }", err);
 231                 err += RXRPC_LOCAL_ERROR_OFFSET;
 232                 break;
 233
 234         case SO_EE_ORIGIN_ICMP6:
 235         default:
 236                 _proto("Rx Received error report { orig=%u }", ee->ee_origin);
 237                 break;
 238         }
 239
 240         peer->error_report = err;
 241 }
 242
 243 /*
 244  * Distribute an error that occurred on a peer
 245  */
 246 void rxrpc_peer_error_distributor(struct work_struct *work)
 247 {
 248         struct rxrpc_peer *peer =
 249                 container_of(work, struct rxrpc_peer, error_distributor);
 250         struct rxrpc_call *call;
 251         int error_report;
 252
 253         _enter("");
 254
 255         error_report = READ_ONCE(peer->error_report);
 256
 257         _debug("ISSUE ERROR %d", error_report);
 258
 259         spin_lock_bh(&peer->lock);
 260
 261         while (!hlist_empty(&peer->error_targets)) {
 262                 call = hlist_entry(peer->error_targets.first,
 263                                    struct rxrpc_call, error_link);
 264                 hlist_del_init(&call->error_link);
 265
 266                 write_lock(&call->state_lock);
 267                 if (call->state != RXRPC_CALL_COMPLETE &&
 268                     call->state < RXRPC_CALL_NETWORK_ERROR) {
 269                         call->error_report = error_report;
 270                         call->state = RXRPC_CALL_NETWORK_ERROR;
 271                         set_bit(RXRPC_CALL_EV_RCVD_ERROR, &call->events);
 272                         rxrpc_queue_call(call);
 273                 }
 274                 write_unlock(&call->state_lock);
 275         }
 276
 277         spin_unlock_bh(&peer->lock);
 278
 279         rxrpc_put_peer(peer);
 280         _leave("");
 281 }