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 "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                        spin_lock_bh(&peer->lock);
 104                        peer->mtu = mtu;
 105                        peer->maxdata = peer->mtu - peer->hdrsize;
 106                        spin_unlock_bh(&peer->lock);
 107                        _net("Net MTU %u (maxdata %u)",
 108                             peer->mtu, peer->maxdata);
 109                }
 110        }
 111
 112        rxrpc_put_peer(peer);
 113
 114        /* pass the transport ref to error_handler to release */
 115        skb_queue_tail(&trans->error_queue, skb);
 116        rxrpc_queue_work(&trans->error_handler);
 117
 118        /* reset and regenerate socket error */
 119        spin_lock_bh(&sk->sk_error_queue.lock);
 120        sk->sk_err = 0;
 121        skb = skb_peek(&sk->sk_error_queue);
 122        if (skb) {
 123                sk->sk_err = SKB_EXT_ERR(skb)->ee.ee_errno;
 124                spin_unlock_bh(&sk->sk_error_queue.lock);
 125                sk->sk_error_report(sk);
 126        } else {
 127                spin_unlock_bh(&sk->sk_error_queue.lock);
 128        }
 129
 130        _leave("");
 131}
 132
 133/*
 134 * deal with UDP error messages
 135 */
 136void rxrpc_UDP_error_handler(struct work_struct *work)
 137{
 138        struct sock_extended_err *ee;
 139        struct sock_exterr_skb *serr;
 140        struct rxrpc_transport *trans =
 141                container_of(work, struct rxrpc_transport, error_handler);
 142        struct sk_buff *skb;
 143        int local, err;
 144
 145        _enter("");
 146
 147        skb = skb_dequeue(&trans->error_queue);
 148        if (!skb)
 149                return;
 150
 151        serr = SKB_EXT_ERR(skb);
 152        ee = &serr->ee;
 153
 154        _net("Rx Error o=%d t=%d c=%d e=%d",
 155             ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
 156
 157        err = ee->ee_errno;
 158
 159        switch (ee->ee_origin) {
 160        case SO_EE_ORIGIN_ICMP:
 161                local = 0;
 162                switch (ee->ee_type) {
 163                case ICMP_DEST_UNREACH:
 164                        switch (ee->ee_code) {
 165                        case ICMP_NET_UNREACH:
 166                                _net("Rx Received ICMP Network Unreachable");
 167                                err = ENETUNREACH;
 168                                break;
 169                        case ICMP_HOST_UNREACH:
 170                                _net("Rx Received ICMP Host Unreachable");
 171                                err = EHOSTUNREACH;
 172                                break;
 173                        case ICMP_PORT_UNREACH:
 174                                _net("Rx Received ICMP Port Unreachable");
 175                                err = ECONNREFUSED;
 176                                break;
 177                        case ICMP_FRAG_NEEDED:
 178                                _net("Rx Received ICMP Fragmentation Needed (%d)",
 179                                     ee->ee_info);
 180                                err = 0; /* dealt with elsewhere */
 181                                break;
 182                        case ICMP_NET_UNKNOWN:
 183                                _net("Rx Received ICMP Unknown Network");
 184                                err = ENETUNREACH;
 185                                break;
 186                        case ICMP_HOST_UNKNOWN:
 187                                _net("Rx Received ICMP Unknown Host");
 188                                err = EHOSTUNREACH;
 189                                break;
 190                        default:
 191                                _net("Rx Received ICMP DestUnreach code=%u",
 192                                     ee->ee_code);
 193                                break;
 194                        }
 195                        break;
 196
 197                case ICMP_TIME_EXCEEDED:
 198                        _net("Rx Received ICMP TTL Exceeded");
 199                        break;
 200
 201                default:
 202                        _proto("Rx Received ICMP error { type=%u code=%u }",
 203                               ee->ee_type, ee->ee_code);
 204                        break;
 205                }
 206                break;
 207
 208        case SO_EE_ORIGIN_LOCAL:
 209                _proto("Rx Received local error { error=%d }",
 210                       ee->ee_errno);
 211                local = 1;
 212                break;
 213
 214        case SO_EE_ORIGIN_NONE:
 215        case SO_EE_ORIGIN_ICMP6:
 216        default:
 217                _proto("Rx Received error report { orig=%u }",
 218                       ee->ee_origin);
 219                local = 0;
 220                break;
 221        }
 222
 223        /* terminate all the affected calls if there's an unrecoverable
 224         * error */
 225        if (err) {
 226                struct rxrpc_call *call, *_n;
 227
 228                _debug("ISSUE ERROR %d", err);
 229
 230                spin_lock_bh(&trans->peer->lock);
 231                trans->peer->net_error = err;
 232
 233                list_for_each_entry_safe(call, _n, &trans->peer->error_targets,
 234                                         error_link) {
 235                        write_lock(&call->state_lock);
 236                        if (call->state != RXRPC_CALL_COMPLETE &&
 237                            call->state < RXRPC_CALL_NETWORK_ERROR) {
 238                                call->state = RXRPC_CALL_NETWORK_ERROR;
 239                                set_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
 240                                rxrpc_queue_call(call);
 241                        }
 242                        write_unlock(&call->state_lock);
 243                        list_del_init(&call->error_link);
 244                }
 245
 246                spin_unlock_bh(&trans->peer->lock);
 247        }
 248
 249        if (!skb_queue_empty(&trans->error_queue))
 250                rxrpc_queue_work(&trans->error_handler);
 251
 252        rxrpc_free_skb(skb);
 253        rxrpc_put_transport(trans);
 254        _leave("");
 255}
 256