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 "NIPQUAD_FMT":%hu",
  53              NIPQUAD(addr), ntohs(port));
  54         _debug("Msg l:%d d:%d", skb->len, skb->data_len);
  55
  56         peer = rxrpc_find_peer(local, addr, port);
  57         if (IS_ERR(peer)) {
  58                 rxrpc_free_skb(skb);
  59                 _leave(" [no peer]");
  60                 return;
  61         }
  62
  63         trans = rxrpc_find_transport(local, peer);
  64         if (!trans) {
  65                 rxrpc_put_peer(peer);
  66                 rxrpc_free_skb(skb);
  67                 _leave(" [no trans]");
  68                 return;
  69         }
  70
  71         if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
  72             serr->ee.ee_type == ICMP_DEST_UNREACH &&
  73             serr->ee.ee_code == ICMP_FRAG_NEEDED
  74             ) {
  75                 u32 mtu = serr->ee.ee_info;
  76
  77                 _net("Rx Received ICMP Fragmentation Needed (%d)", mtu);
  78
  79                 /* wind down the local interface MTU */
  80                 if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
  81                         peer->if_mtu = mtu;
  82                         _net("I/F MTU %u", mtu);
  83                 }
  84
  85                 /* ip_rt_frag_needed() may have eaten the info */
  86                 if (mtu == 0)
  87                         mtu = ntohs(icmp_hdr(skb)->un.frag.mtu);
  88
  89                 if (mtu == 0) {
  90                         /* they didn't give us a size, estimate one */
  91                         if (mtu > 1500) {
  92                                 mtu >>= 1;
  93                                 if (mtu < 1500)
  94                                         mtu = 1500;
  95                         } else {
  96                                 mtu -= 100;
  97                                 if (mtu < peer->hdrsize)
  98                                         mtu = peer->hdrsize + 4;
  99                         }
 100                 }
 101
 102                 if (mtu < peer->mtu) {
 103                         peer->mtu = mtu;
 104                         peer->maxdata = peer->mtu - peer->hdrsize;
 105                         _net("Net MTU %u (maxdata %u)",
 106                              peer->mtu, peer->maxdata);
 107                 }
 108         }
 109
 110         rxrpc_put_peer(peer);
 111
 112         /* pass the transport ref to error_handler to release */
 113         skb_queue_tail(&trans->error_queue, skb);
 114         rxrpc_queue_work(&trans->error_handler);
 115
 116         /* reset and regenerate socket error */
 117         spin_lock_bh(&sk->sk_error_queue.lock);
 118         sk->sk_err = 0;
 119         skb = skb_peek(&sk->sk_error_queue);
 120         if (skb) {
 121                 sk->sk_err = SKB_EXT_ERR(skb)->ee.ee_errno;
 122                 spin_unlock_bh(&sk->sk_error_queue.lock);
 123                 sk->sk_error_report(sk);
 124         } else {
 125                 spin_unlock_bh(&sk->sk_error_queue.lock);
 126         }
 127
 128         _leave("");
 129 }
 130
 131 /*
 132  * deal with UDP error messages
 133  */
 134 void rxrpc_UDP_error_handler(struct work_struct *work)
 135 {
 136         struct sock_extended_err *ee;
 137         struct sock_exterr_skb *serr;
 138         struct rxrpc_transport *trans =
 139                 container_of(work, struct rxrpc_transport, error_handler);
 140         struct sk_buff *skb;
 141         int local, err;
 142
 143         _enter("");
 144
 145         skb = skb_dequeue(&trans->error_queue);
 146         if (!skb)
 147                 return;
 148
 149         serr = SKB_EXT_ERR(skb);
 150         ee = &serr->ee;
 151
 152         _net("Rx Error o=%d t=%d c=%d e=%d",
 153              ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
 154
 155         err = ee->ee_errno;
 156
 157         switch (ee->ee_origin) {
 158         case SO_EE_ORIGIN_ICMP:
 159                 local = 0;
 160                 switch (ee->ee_type) {
 161                 case ICMP_DEST_UNREACH:
 162                         switch (ee->ee_code) {
 163                         case ICMP_NET_UNREACH:
 164                                 _net("Rx Received ICMP Network Unreachable");
 165                                 err = ENETUNREACH;
 166                                 break;
 167                         case ICMP_HOST_UNREACH:
 168                                 _net("Rx Received ICMP Host Unreachable");
 169                                 err = EHOSTUNREACH;
 170                                 break;
 171                         case ICMP_PORT_UNREACH:
 172                                 _net("Rx Received ICMP Port Unreachable");
 173                                 err = ECONNREFUSED;
 174                                 break;
 175                         case ICMP_FRAG_NEEDED:
 176                                 _net("Rx Received ICMP Fragmentation Needed (%d)",
 177                                      ee->ee_info);
 178                                 err = 0; /* dealt with elsewhere */
 179                                 break;
 180                         case ICMP_NET_UNKNOWN:
 181                                 _net("Rx Received ICMP Unknown Network");
 182                                 err = ENETUNREACH;
 183                                 break;
 184                         case ICMP_HOST_UNKNOWN:
 185                                 _net("Rx Received ICMP Unknown Host");
 186                                 err = EHOSTUNREACH;
 187                                 break;
 188                         default:
 189                                 _net("Rx Received ICMP DestUnreach code=%u",
 190                                      ee->ee_code);
 191                                 break;
 192                         }
 193                         break;
 194
 195                 case ICMP_TIME_EXCEEDED:
 196                         _net("Rx Received ICMP TTL Exceeded");
 197                         break;
 198
 199                 default:
 200                         _proto("Rx Received ICMP error { type=%u code=%u }",
 201                                ee->ee_type, ee->ee_code);
 202                         break;
 203                 }
 204                 break;
 205
 206         case SO_EE_ORIGIN_LOCAL:
 207                 _proto("Rx Received local error { error=%d }",
 208                        ee->ee_errno);
 209                 local = 1;
 210                 break;
 211
 212         case SO_EE_ORIGIN_NONE:
 213         case SO_EE_ORIGIN_ICMP6:
 214         default:
 215                 _proto("Rx Received error report { orig=%u }",
 216                        ee->ee_origin);
 217                 local = 0;
 218                 break;
 219         }
 220
 221         /* terminate all the affected calls if there's an unrecoverable
 222          * error */
 223         if (err) {
 224                 struct rxrpc_call *call, *_n;
 225
 226                 _debug("ISSUE ERROR %d", err);
 227
 228                 spin_lock_bh(&trans->peer->lock);
 229                 trans->peer->net_error = err;
 230
 231                 list_for_each_entry_safe(call, _n, &trans->peer->error_targets,
 232                                          error_link) {
 233                         write_lock(&call->state_lock);
 234                         if (call->state != RXRPC_CALL_COMPLETE &&
 235                             call->state < RXRPC_CALL_NETWORK_ERROR) {
 236                                 call->state = RXRPC_CALL_NETWORK_ERROR;
 237                                 set_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
 238                                 rxrpc_queue_call(call);
 239                         }
 240                         write_unlock(&call->state_lock);
 241                         list_del_init(&call->error_link);
 242                 }
 243
 244                 spin_unlock_bh(&trans->peer->lock);
 245         }
 246
 247         if (!skb_queue_empty(&trans->error_queue))
 248                 rxrpc_queue_work(&trans->error_handler);
 249
 250         rxrpc_free_skb(skb);
 251         rxrpc_put_transport(trans);
 252         _leave("");
 253 }