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                /* ip_rt_frag_needed() may have eaten the info */
  85                if (mtu == 0)
  86                        mtu = ntohs(icmp_hdr(skb)->un.frag.mtu);
  87
  88                if (mtu == 0) {
  89                        /* they didn't give us a size, estimate one */
  90                        if (mtu > 1500) {
  91                                mtu >>= 1;
  92                                if (mtu < 1500)
  93                                        mtu = 1500;
  94                        } else {
  95                                mtu -= 100;
  96                                if (mtu < peer->hdrsize)
  97                                        mtu = peer->hdrsize + 4;
  98                        }
  99                }
 100
 101                if (mtu < peer->mtu) {
 102                        spin_lock_bh(&peer->lock);
 103                        peer->mtu = mtu;
 104                        peer->maxdata = peer->mtu - peer->hdrsize;
 105                        spin_unlock_bh(&peer->lock);
 106                        _net("Net MTU %u (maxdata %u)",
 107                             peer->mtu, peer->maxdata);
 108                }
 109        }
 110
 111        rxrpc_put_peer(peer);
 112
 113        /* pass the transport ref to error_handler to release */
 114        skb_queue_tail(&trans->error_queue, skb);
 115        rxrpc_queue_work(&trans->error_handler);
 116
 117        /* reset and regenerate socket error */
 118        spin_lock_bh(&sk->sk_error_queue.lock);
 119        sk->sk_err = 0;
 120        skb = skb_peek(&sk->sk_error_queue);
 121        if (skb) {
 122                sk->sk_err = SKB_EXT_ERR(skb)->ee.ee_errno;
 123                spin_unlock_bh(&sk->sk_error_queue.lock);
 124                sk->sk_error_report(sk);
 125        } else {
 126                spin_unlock_bh(&sk->sk_error_queue.lock);
 127        }
 128
 129        _leave("");
 130}
 131
 132/*
 133 * deal with UDP error messages
 134 */
 135void rxrpc_UDP_error_handler(struct work_struct *work)
 136{
 137        struct sock_extended_err *ee;
 138        struct sock_exterr_skb *serr;
 139        struct rxrpc_transport *trans =
 140                container_of(work, struct rxrpc_transport, error_handler);
 141        struct sk_buff *skb;
 142        int local, err;
 143
 144        _enter("");
 145
 146        skb = skb_dequeue(&trans->error_queue);
 147        if (!skb)
 148                return;
 149
 150        serr = SKB_EXT_ERR(skb);
 151        ee = &serr->ee;
 152
 153        _net("Rx Error o=%d t=%d c=%d e=%d",
 154             ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
 155
 156        err = ee->ee_errno;
 157
 158        switch (ee->ee_origin) {
 159        case SO_EE_ORIGIN_ICMP:
 160                local = 0;
 161                switch (ee->ee_type) {
 162                case ICMP_DEST_UNREACH:
 163                        switch (ee->ee_code) {
 164                        case ICMP_NET_UNREACH:
 165                                _net("Rx Received ICMP Network Unreachable");
 166                                err = ENETUNREACH;
 167                                break;
 168                        case ICMP_HOST_UNREACH:
 169                                _net("Rx Received ICMP Host Unreachable");
 170                                err = EHOSTUNREACH;
 171                                break;
 172                        case ICMP_PORT_UNREACH:
 173                                _net("Rx Received ICMP Port Unreachable");
 174                                err = ECONNREFUSED;
 175                                break;
 176                        case ICMP_FRAG_NEEDED:
 177                                _net("Rx Received ICMP Fragmentation Needed (%d)",
 178                                     ee->ee_info);
 179                                err = 0; /* dealt with elsewhere */
 180                                break;
 181                        case ICMP_NET_UNKNOWN:
 182                                _net("Rx Received ICMP Unknown Network");
 183                                err = ENETUNREACH;
 184                                break;
 185                        case ICMP_HOST_UNKNOWN:
 186                                _net("Rx Received ICMP Unknown Host");
 187                                err = EHOSTUNREACH;
 188                                break;
 189                        default:
 190                                _net("Rx Received ICMP DestUnreach code=%u",
 191                                     ee->ee_code);
 192                                break;
 193                        }
 194                        break;
 195
 196                case ICMP_TIME_EXCEEDED:
 197                        _net("Rx Received ICMP TTL Exceeded");
 198                        break;
 199
 200                default:
 201                        _proto("Rx Received ICMP error { type=%u code=%u }",
 202                               ee->ee_type, ee->ee_code);
 203                        break;
 204                }
 205                break;
 206
 207        case SO_EE_ORIGIN_LOCAL:
 208                _proto("Rx Received local error { error=%d }",
 209                       ee->ee_errno);
 210                local = 1;
 211                break;
 212
 213        case SO_EE_ORIGIN_NONE:
 214        case SO_EE_ORIGIN_ICMP6:
 215        default:
 216                _proto("Rx Received error report { orig=%u }",
 217                       ee->ee_origin);
 218                local = 0;
 219                break;
 220        }
 221
 222        /* terminate all the affected calls if there's an unrecoverable
 223         * error */
 224        if (err) {
 225                struct rxrpc_call *call, *_n;
 226
 227                _debug("ISSUE ERROR %d", err);
 228
 229                spin_lock_bh(&trans->peer->lock);
 230                trans->peer->net_error = err;
 231
 232                list_for_each_entry_safe(call, _n, &trans->peer->error_targets,
 233                                         error_link) {
 234                        write_lock(&call->state_lock);
 235                        if (call->state != RXRPC_CALL_COMPLETE &&
 236                            call->state < RXRPC_CALL_NETWORK_ERROR) {
 237                                call->state = RXRPC_CALL_NETWORK_ERROR;
 238                                set_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
 239                                rxrpc_queue_call(call);
 240                        }
 241                        write_unlock(&call->state_lock);
 242                        list_del_init(&call->error_link);
 243                }
 244
 245                spin_unlock_bh(&trans->peer->lock);
 246        }
 247
 248        if (!skb_queue_empty(&trans->error_queue))
 249                rxrpc_queue_work(&trans->error_handler);
 250
 251        rxrpc_free_skb(skb);
 252        rxrpc_put_transport(trans);
 253        _leave("");
 254}
 255