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 = 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
 119        _leave("");
 120}
 121
 122/*
 123 * deal with UDP error messages
 124 */
 125void rxrpc_UDP_error_handler(struct work_struct *work)
 126{
 127        struct sock_extended_err *ee;
 128        struct sock_exterr_skb *serr;
 129        struct rxrpc_transport *trans =
 130                container_of(work, struct rxrpc_transport, error_handler);
 131        struct sk_buff *skb;
 132        int err;
 133
 134        _enter("");
 135
 136        skb = skb_dequeue(&trans->error_queue);
 137        if (!skb)
 138                return;
 139
 140        serr = SKB_EXT_ERR(skb);
 141        ee = &serr->ee;
 142
 143        _net("Rx Error o=%d t=%d c=%d e=%d",
 144             ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
 145
 146        err = ee->ee_errno;
 147
 148        switch (ee->ee_origin) {
 149        case SO_EE_ORIGIN_ICMP:
 150                switch (ee->ee_type) {
 151                case ICMP_DEST_UNREACH:
 152                        switch (ee->ee_code) {
 153                        case ICMP_NET_UNREACH:
 154                                _net("Rx Received ICMP Network Unreachable");
 155                                err = ENETUNREACH;
 156                                break;
 157                        case ICMP_HOST_UNREACH:
 158                                _net("Rx Received ICMP Host Unreachable");
 159                                err = EHOSTUNREACH;
 160                                break;
 161                        case ICMP_PORT_UNREACH:
 162                                _net("Rx Received ICMP Port Unreachable");
 163                                err = ECONNREFUSED;
 164                                break;
 165                        case ICMP_FRAG_NEEDED:
 166                                _net("Rx Received ICMP Fragmentation Needed (%d)",
 167                                     ee->ee_info);
 168                                err = 0; /* dealt with elsewhere */
 169                                break;
 170                        case ICMP_NET_UNKNOWN:
 171                                _net("Rx Received ICMP Unknown Network");
 172                                err = ENETUNREACH;
 173                                break;
 174                        case ICMP_HOST_UNKNOWN:
 175                                _net("Rx Received ICMP Unknown Host");
 176                                err = EHOSTUNREACH;
 177                                break;
 178                        default:
 179                                _net("Rx Received ICMP DestUnreach code=%u",
 180                                     ee->ee_code);
 181                                break;
 182                        }
 183                        break;
 184
 185                case ICMP_TIME_EXCEEDED:
 186                        _net("Rx Received ICMP TTL Exceeded");
 187                        break;
 188
 189                default:
 190                        _proto("Rx Received ICMP error { type=%u code=%u }",
 191                               ee->ee_type, ee->ee_code);
 192                        break;
 193                }
 194                break;
 195
 196        case SO_EE_ORIGIN_LOCAL:
 197                _proto("Rx Received local error { error=%d }",
 198                       ee->ee_errno);
 199                break;
 200
 201        case SO_EE_ORIGIN_NONE:
 202        case SO_EE_ORIGIN_ICMP6:
 203        default:
 204                _proto("Rx Received error report { orig=%u }",
 205                       ee->ee_origin);
 206                break;
 207        }
 208
 209        /* terminate all the affected calls if there's an unrecoverable
 210         * error */
 211        if (err) {
 212                struct rxrpc_call *call, *_n;
 213
 214                _debug("ISSUE ERROR %d", err);
 215
 216                spin_lock_bh(&trans->peer->lock);
 217                trans->peer->net_error = err;
 218
 219                list_for_each_entry_safe(call, _n, &trans->peer->error_targets,
 220                                         error_link) {
 221                        write_lock(&call->state_lock);
 222                        if (call->state != RXRPC_CALL_COMPLETE &&
 223                            call->state < RXRPC_CALL_NETWORK_ERROR) {
 224                                call->state = RXRPC_CALL_NETWORK_ERROR;
 225                                set_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
 226                                rxrpc_queue_call(call);
 227                        }
 228                        write_unlock(&call->state_lock);
 229                        list_del_init(&call->error_link);
 230                }
 231
 232                spin_unlock_bh(&trans->peer->lock);
 233        }
 234
 235        if (!skb_queue_empty(&trans->error_queue))
 236                rxrpc_queue_work(&trans->error_handler);
 237
 238        rxrpc_free_skb(skb);
 239        rxrpc_put_transport(trans);
 240        _leave("");
 241}
 242