net/rxrpc/ar-error.c

   1 /* Error message handling (ICMP)
   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 /*
  26  * handle an error received on the local endpoint
  27  */
  28 void rxrpc_UDP_error_report(struct sock *sk)
  29 {
  30         struct sock_exterr_skb *serr;
  31         struct rxrpc_transport *trans;
  32         struct rxrpc_local *local = sk->sk_user_data;
  33         struct rxrpc_peer *peer;
  34         struct sk_buff *skb;
  35         __be32 addr;
  36         __be16 port;
  37
  38         _enter("%p{%d}", sk, local->debug_id);
  39
  40         skb = sock_dequeue_err_skb(sk);
  41         if (!skb) {
  42                 _leave("UDP socket errqueue empty");
  43                 return;
  44         }
  45         serr = SKB_EXT_ERR(skb);
  46         if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
  47                 _leave("UDP empty message");
  48                 kfree_skb(skb);
  49                 return;
  50         }
  51
  52         rxrpc_new_skb(skb);
  53
  54         addr = *(__be32 *)(skb_network_header(skb) + serr->addr_offset);
  55         port = serr->port;
  56
  57         _net("Rx UDP Error from %pI4:%hu", &addr, ntohs(port));
  58         _debug("Msg l:%d d:%d", skb->len, skb->data_len);
  59
  60         peer = rxrpc_find_peer(local, addr, port);
  61         if (IS_ERR(peer)) {
  62                 rxrpc_free_skb(skb);
  63                 _leave(" [no peer]");
  64                 return;
  65         }
  66
  67         trans = rxrpc_find_transport(local, peer);
  68         if (!trans) {
  69                 rxrpc_put_peer(peer);
  70                 rxrpc_free_skb(skb);
  71                 _leave(" [no trans]");
  72                 return;
  73         }
  74
  75         if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
  76             serr->ee.ee_type == ICMP_DEST_UNREACH &&
  77             serr->ee.ee_code == ICMP_FRAG_NEEDED
  78             ) {
  79                 u32 mtu = serr->ee.ee_info;
  80
  81                 _net("Rx Received ICMP Fragmentation Needed (%d)", mtu);
  82
  83                 /* wind down the local interface MTU */
  84                 if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
  85                         peer->if_mtu = mtu;
  86                         _net("I/F MTU %u", mtu);
  87                 }
  88
  89                 if (mtu == 0) {
  90                         /* they didn't give us a size, estimate one */
  91                         mtu = peer->if_mtu;
  92                         if (mtu > 1500) {
  93                                 mtu >>= 1;
  94                                 if (mtu < 1500)
  95                                         mtu = 1500;
  96                         } else {
  97                                 mtu -= 100;
  98                                 if (mtu < peer->hdrsize)
  99                                         mtu = peer->hdrsize + 4;
 100                         }
 101                 }
 102
 103                 if (mtu < peer->mtu) {
 104                         spin_lock_bh(&peer->lock);
 105                         peer->mtu = mtu;
 106                         peer->maxdata = peer->mtu - peer->hdrsize;
 107                         spin_unlock_bh(&peer->lock);
 108                         _net("Net MTU %u (maxdata %u)",
 109                              peer->mtu, peer->maxdata);
 110                 }
 111         }
 112
 113         rxrpc_put_peer(peer);
 114
 115         /* pass the transport ref to error_handler to release */
 116         skb_queue_tail(&trans->error_queue, skb);
 117         rxrpc_queue_work(&trans->error_handler);
 118         _leave("");
 119 }
 120
 121 /*
 122  * deal with UDP error messages
 123  */
 124 void rxrpc_UDP_error_handler(struct work_struct *work)
 125 {
 126         struct sock_extended_err *ee;
 127         struct sock_exterr_skb *serr;
 128         struct rxrpc_transport *trans =
 129                 container_of(work, struct rxrpc_transport, error_handler);
 130         struct sk_buff *skb;
 131         int err;
 132
 133         _enter("");
 134
 135         skb = skb_dequeue(&trans->error_queue);
 136         if (!skb)
 137                 return;
 138
 139         serr = SKB_EXT_ERR(skb);
 140         ee = &serr->ee;
 141
 142         _net("Rx Error o=%d t=%d c=%d e=%d",
 143              ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
 144
 145         err = ee->ee_errno;
 146
 147         switch (ee->ee_origin) {
 148         case SO_EE_ORIGIN_ICMP:
 149                 switch (ee->ee_type) {
 150                 case ICMP_DEST_UNREACH:
 151                         switch (ee->ee_code) {
 152                         case ICMP_NET_UNREACH:
 153                                 _net("Rx Received ICMP Network Unreachable");
 154                                 err = ENETUNREACH;
 155                                 break;
 156                         case ICMP_HOST_UNREACH:
 157                                 _net("Rx Received ICMP Host Unreachable");
 158                                 err = EHOSTUNREACH;
 159                                 break;
 160                         case ICMP_PORT_UNREACH:
 161                                 _net("Rx Received ICMP Port Unreachable");
 162                                 err = ECONNREFUSED;
 163                                 break;
 164                         case ICMP_FRAG_NEEDED:
 165                                 _net("Rx Received ICMP Fragmentation Needed (%d)",
 166                                      ee->ee_info);
 167                                 err = 0; /* dealt with elsewhere */
 168                                 break;
 169                         case ICMP_NET_UNKNOWN:
 170                                 _net("Rx Received ICMP Unknown Network");
 171                                 err = ENETUNREACH;
 172                                 break;
 173                         case ICMP_HOST_UNKNOWN:
 174                                 _net("Rx Received ICMP Unknown Host");
 175                                 err = EHOSTUNREACH;
 176                                 break;
 177                         default:
 178                                 _net("Rx Received ICMP DestUnreach code=%u",
 179                                      ee->ee_code);
 180                                 break;
 181                         }
 182                         break;
 183
 184                 case ICMP_TIME_EXCEEDED:
 185                         _net("Rx Received ICMP TTL Exceeded");
 186                         break;
 187
 188                 default:
 189                         _proto("Rx Received ICMP error { type=%u code=%u }",
 190                                ee->ee_type, ee->ee_code);
 191                         break;
 192                 }
 193                 break;
 194
 195         case SO_EE_ORIGIN_LOCAL:
 196                 _proto("Rx Received local error { error=%d }",
 197                        ee->ee_errno);
 198                 break;
 199
 200         case SO_EE_ORIGIN_NONE:
 201         case SO_EE_ORIGIN_ICMP6:
 202         default:
 203                 _proto("Rx Received error report { orig=%u }",
 204                        ee->ee_origin);
 205                 break;
 206         }
 207
 208         /* terminate all the affected calls if there's an unrecoverable
 209          * error */
 210         if (err) {
 211                 struct rxrpc_call *call, *_n;
 212
 213                 _debug("ISSUE ERROR %d", err);
 214
 215                 spin_lock_bh(&trans->peer->lock);
 216                 trans->peer->net_error = err;
 217
 218                 list_for_each_entry_safe(call, _n, &trans->peer->error_targets,
 219                                          error_link) {
 220                         write_lock(&call->state_lock);
 221                         if (call->state != RXRPC_CALL_COMPLETE &&
 222                             call->state < RXRPC_CALL_NETWORK_ERROR) {
 223                                 call->state = RXRPC_CALL_NETWORK_ERROR;
 224                                 set_bit(RXRPC_CALL_EV_RCVD_ERROR, &call->events);
 225                                 rxrpc_queue_call(call);
 226                         }
 227                         write_unlock(&call->state_lock);
 228                         list_del_init(&call->error_link);
 229                 }
 230
 231                 spin_unlock_bh(&trans->peer->lock);
 232         }
 233
 234         if (!skb_queue_empty(&trans->error_queue))
 235                 rxrpc_queue_work(&trans->error_handler);
 236
 237         rxrpc_free_skb(skb);
 238         rxrpc_put_transport(trans);
 239         _leave("");
 240 }