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 = skb_dequeue(&sk->sk_error_queue);
  41         if (!skb) {
  42                 _leave("UDP socket errqueue empty");
  43                 return;
  44         }
  45
  46         rxrpc_new_skb(skb);
  47
  48         serr = SKB_EXT_ERR(skb);
  49         addr = *(__be32 *)(skb_network_header(skb) + serr->addr_offset);
  50         port = serr->port;
  51
  52         _net("Rx UDP Error from %pI4:%hu", &addr, ntohs(port));
  53         _debug("Msg l:%d d:%d", skb->len, skb->data_len);
  54
  55         peer = rxrpc_find_peer(local, addr, port);
  56         if (IS_ERR(peer)) {
  57                 rxrpc_free_skb(skb);
  58                 _leave(" [no peer]");
  59                 return;
  60         }
  61
  62         trans = rxrpc_find_transport(local, peer);
  63         if (!trans) {
  64                 rxrpc_put_peer(peer);
  65                 rxrpc_free_skb(skb);
  66                 _leave(" [no trans]");
  67                 return;
  68         }
  69
  70         if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
  71             serr->ee.ee_type == ICMP_DEST_UNREACH &&
  72             serr->ee.ee_code == ICMP_FRAG_NEEDED
  73             ) {
  74                 u32 mtu = serr->ee.ee_info;
  75
  76                 _net("Rx Received ICMP Fragmentation Needed (%d)", mtu);
  77
  78                 /* wind down the local interface MTU */
  79                 if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
  80                         peer->if_mtu = mtu;
  81                         _net("I/F MTU %u", mtu);
  82                 }
  83
  84                 if (mtu == 0) {
  85                         /* they didn't give us a size, estimate one */
  86                         mtu = peer->if_mtu;
  87                         if (mtu > 1500) {
  88                                 mtu >>= 1;
  89                                 if (mtu < 1500)
  90                                         mtu = 1500;
  91                         } else {
  92                                 mtu -= 100;
  93                                 if (mtu < peer->hdrsize)
  94                                         mtu = peer->hdrsize + 4;
  95                         }
  96                 }
  97
  98                 if (mtu < peer->mtu) {
  99                         spin_lock_bh(&peer->lock);
 100                         peer->mtu = mtu;
 101                         peer->maxdata = peer->mtu - peer->hdrsize;
 102                         spin_unlock_bh(&peer->lock);
 103                         _net("Net MTU %u (maxdata %u)",
 104                              peer->mtu, peer->maxdata);
 105                 }
 106         }
 107
 108         rxrpc_put_peer(peer);
 109
 110         /* pass the transport ref to error_handler to release */
 111         skb_queue_tail(&trans->error_queue, skb);
 112         rxrpc_queue_work(&trans->error_handler);
 113
 114         /* reset and regenerate socket error */
 115         spin_lock_bh(&sk->sk_error_queue.lock);
 116         sk->sk_err = 0;
 117         skb = skb_peek(&sk->sk_error_queue);
 118         if (skb) {
 119                 sk->sk_err = SKB_EXT_ERR(skb)->ee.ee_errno;
 120                 spin_unlock_bh(&sk->sk_error_queue.lock);
 121                 sk->sk_error_report(sk);
 122         } else {
 123                 spin_unlock_bh(&sk->sk_error_queue.lock);
 124         }
 125
 126         _leave("");
 127 }
 128
 129 /*
 130  * deal with UDP error messages
 131  */
 132 void rxrpc_UDP_error_handler(struct work_struct *work)
 133 {
 134         struct sock_extended_err *ee;
 135         struct sock_exterr_skb *serr;
 136         struct rxrpc_transport *trans =
 137                 container_of(work, struct rxrpc_transport, error_handler);
 138         struct sk_buff *skb;
 139         int err;
 140
 141         _enter("");
 142
 143         skb = skb_dequeue(&trans->error_queue);
 144         if (!skb)
 145                 return;
 146
 147         serr = SKB_EXT_ERR(skb);
 148         ee = &serr->ee;
 149
 150         _net("Rx Error o=%d t=%d c=%d e=%d",
 151              ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
 152
 153         err = ee->ee_errno;
 154
 155         switch (ee->ee_origin) {
 156         case SO_EE_ORIGIN_ICMP:
 157                 switch (ee->ee_type) {
 158                 case ICMP_DEST_UNREACH:
 159                         switch (ee->ee_code) {
 160                         case ICMP_NET_UNREACH:
 161                                 _net("Rx Received ICMP Network Unreachable");
 162                                 err = ENETUNREACH;
 163                                 break;
 164                         case ICMP_HOST_UNREACH:
 165                                 _net("Rx Received ICMP Host Unreachable");
 166                                 err = EHOSTUNREACH;
 167                                 break;
 168                         case ICMP_PORT_UNREACH:
 169                                 _net("Rx Received ICMP Port Unreachable");
 170                                 err = ECONNREFUSED;
 171                                 break;
 172                         case ICMP_FRAG_NEEDED:
 173                                 _net("Rx Received ICMP Fragmentation Needed (%d)",
 174                                      ee->ee_info);
 175                                 err = 0; /* dealt with elsewhere */
 176                                 break;
 177                         case ICMP_NET_UNKNOWN:
 178                                 _net("Rx Received ICMP Unknown Network");
 179                                 err = ENETUNREACH;
 180                                 break;
 181                         case ICMP_HOST_UNKNOWN:
 182                                 _net("Rx Received ICMP Unknown Host");
 183                                 err = EHOSTUNREACH;
 184                                 break;
 185                         default:
 186                                 _net("Rx Received ICMP DestUnreach code=%u",
 187                                      ee->ee_code);
 188                                 break;
 189                         }
 190                         break;
 191
 192                 case ICMP_TIME_EXCEEDED:
 193                         _net("Rx Received ICMP TTL Exceeded");
 194                         break;
 195
 196                 default:
 197                         _proto("Rx Received ICMP error { type=%u code=%u }",
 198                                ee->ee_type, ee->ee_code);
 199                         break;
 200                 }
 201                 break;
 202
 203         case SO_EE_ORIGIN_LOCAL:
 204                 _proto("Rx Received local error { error=%d }",
 205                        ee->ee_errno);
 206                 break;
 207
 208         case SO_EE_ORIGIN_NONE:
 209         case SO_EE_ORIGIN_ICMP6:
 210         default:
 211                 _proto("Rx Received error report { orig=%u }",
 212                        ee->ee_origin);
 213                 break;
 214         }
 215
 216         /* terminate all the affected calls if there's an unrecoverable
 217          * error */
 218         if (err) {
 219                 struct rxrpc_call *call, *_n;
 220
 221                 _debug("ISSUE ERROR %d", err);
 222
 223                 spin_lock_bh(&trans->peer->lock);
 224                 trans->peer->net_error = err;
 225
 226                 list_for_each_entry_safe(call, _n, &trans->peer->error_targets,
 227                                          error_link) {
 228                         write_lock(&call->state_lock);
 229                         if (call->state != RXRPC_CALL_COMPLETE &&
 230                             call->state < RXRPC_CALL_NETWORK_ERROR) {
 231                                 call->state = RXRPC_CALL_NETWORK_ERROR;
 232                                 set_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
 233                                 rxrpc_queue_call(call);
 234                         }
 235                         write_unlock(&call->state_lock);
 236                         list_del_init(&call->error_link);
 237                 }
 238
 239                 spin_unlock_bh(&trans->peer->lock);
 240         }
 241
 242         if (!skb_queue_empty(&trans->error_queue))
 243                 rxrpc_queue_work(&trans->error_handler);
 244
 245         rxrpc_free_skb(skb);
 246         rxrpc_put_transport(trans);
 247         _leave("");
 248 }