linux/net/rxrpc/ar-error.c
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   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 */
  28void 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                        if (mtu > 1500) {
  87                                mtu >>= 1;
  88                                if (mtu < 1500)
  89                                        mtu = 1500;
  90                        } else {
  91                                mtu -= 100;
  92                                if (mtu < peer->hdrsize)
  93                                        mtu = peer->hdrsize + 4;
  94                        }
  95                }
  96
  97                if (mtu < peer->mtu) {
  98                        spin_lock_bh(&peer->lock);
  99                        peer->mtu = mtu;
 100                        peer->maxdata = peer->mtu - peer->hdrsize;
 101                        spin_unlock_bh(&peer->lock);
 102                        _net("Net MTU %u (maxdata %u)",
 103                             peer->mtu, peer->maxdata);
 104                }
 105        }
 106
 107        rxrpc_put_peer(peer);
 108
 109        /* pass the transport ref to error_handler to release */
 110        skb_queue_tail(&trans->error_queue, skb);
 111        rxrpc_queue_work(&trans->error_handler);
 112
 113        /* reset and regenerate socket error */
 114        spin_lock_bh(&sk->sk_error_queue.lock);
 115        sk->sk_err = 0;
 116        skb = skb_peek(&sk->sk_error_queue);
 117        if (skb) {
 118                sk->sk_err = SKB_EXT_ERR(skb)->ee.ee_errno;
 119                spin_unlock_bh(&sk->sk_error_queue.lock);
 120                sk->sk_error_report(sk);
 121        } else {
 122                spin_unlock_bh(&sk->sk_error_queue.lock);
 123        }
 124
 125        _leave("");
 126}
 127
 128/*
 129 * deal with UDP error messages
 130 */
 131void rxrpc_UDP_error_handler(struct work_struct *work)
 132{
 133        struct sock_extended_err *ee;
 134        struct sock_exterr_skb *serr;
 135        struct rxrpc_transport *trans =
 136                container_of(work, struct rxrpc_transport, error_handler);
 137        struct sk_buff *skb;
 138        int err;
 139
 140        _enter("");
 141
 142        skb = skb_dequeue(&trans->error_queue);
 143        if (!skb)
 144                return;
 145
 146        serr = SKB_EXT_ERR(skb);
 147        ee = &serr->ee;
 148
 149        _net("Rx Error o=%d t=%d c=%d e=%d",
 150             ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
 151
 152        err = ee->ee_errno;
 153
 154        switch (ee->ee_origin) {
 155        case SO_EE_ORIGIN_ICMP:
 156                switch (ee->ee_type) {
 157                case ICMP_DEST_UNREACH:
 158                        switch (ee->ee_code) {
 159                        case ICMP_NET_UNREACH:
 160                                _net("Rx Received ICMP Network Unreachable");
 161                                err = ENETUNREACH;
 162                                break;
 163                        case ICMP_HOST_UNREACH:
 164                                _net("Rx Received ICMP Host Unreachable");
 165                                err = EHOSTUNREACH;
 166                                break;
 167                        case ICMP_PORT_UNREACH:
 168                                _net("Rx Received ICMP Port Unreachable");
 169                                err = ECONNREFUSED;
 170                                break;
 171                        case ICMP_FRAG_NEEDED:
 172                                _net("Rx Received ICMP Fragmentation Needed (%d)",
 173                                     ee->ee_info);
 174                                err = 0; /* dealt with elsewhere */
 175                                break;
 176                        case ICMP_NET_UNKNOWN:
 177                                _net("Rx Received ICMP Unknown Network");
 178                                err = ENETUNREACH;
 179                                break;
 180                        case ICMP_HOST_UNKNOWN:
 181                                _net("Rx Received ICMP Unknown Host");
 182                                err = EHOSTUNREACH;
 183                                break;
 184                        default:
 185                                _net("Rx Received ICMP DestUnreach code=%u",
 186                                     ee->ee_code);
 187                                break;
 188                        }
 189                        break;
 190
 191                case ICMP_TIME_EXCEEDED:
 192                        _net("Rx Received ICMP TTL Exceeded");
 193                        break;
 194
 195                default:
 196                        _proto("Rx Received ICMP error { type=%u code=%u }",
 197                               ee->ee_type, ee->ee_code);
 198                        break;
 199                }
 200                break;
 201
 202        case SO_EE_ORIGIN_LOCAL:
 203                _proto("Rx Received local error { error=%d }",
 204                       ee->ee_errno);
 205                break;
 206
 207        case SO_EE_ORIGIN_NONE:
 208        case SO_EE_ORIGIN_ICMP6:
 209        default:
 210                _proto("Rx Received error report { orig=%u }",
 211                       ee->ee_origin);
 212                break;
 213        }
 214
 215        /* terminate all the affected calls if there's an unrecoverable
 216         * error */
 217        if (err) {
 218                struct rxrpc_call *call, *_n;
 219
 220                _debug("ISSUE ERROR %d", err);
 221
 222                spin_lock_bh(&trans->peer->lock);
 223                trans->peer->net_error = err;
 224
 225                list_for_each_entry_safe(call, _n, &trans->peer->error_targets,
 226                                         error_link) {
 227                        write_lock(&call->state_lock);
 228                        if (call->state != RXRPC_CALL_COMPLETE &&
 229                            call->state < RXRPC_CALL_NETWORK_ERROR) {
 230                                call->state = RXRPC_CALL_NETWORK_ERROR;
 231                                set_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
 232                                rxrpc_queue_call(call);
 233                        }
 234                        write_unlock(&call->state_lock);
 235                        list_del_init(&call->error_link);
 236                }
 237
 238                spin_unlock_bh(&trans->peer->lock);
 239        }
 240
 241        if (!skb_queue_empty(&trans->error_queue))
 242                rxrpc_queue_work(&trans->error_handler);
 243
 244        rxrpc_free_skb(skb);
 245        rxrpc_put_transport(trans);
 246        _leave("");
 247}
 248
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