linux/net/rxrpc/peer_event.c
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   1/* Peer event handling, typically ICMP messages.
   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
  25static void rxrpc_store_error(struct rxrpc_peer *, struct sock_exterr_skb *);
  26
  27/*
  28 * Find the peer associated with an ICMP packet.
  29 */
  30static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local,
  31                                                     const struct sk_buff *skb)
  32{
  33        struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
  34        struct sockaddr_rxrpc srx;
  35
  36        _enter("");
  37
  38        memset(&srx, 0, sizeof(srx));
  39        srx.transport_type = local->srx.transport_type;
  40        srx.transport.family = local->srx.transport.family;
  41
  42        /* Can we see an ICMP4 packet on an ICMP6 listening socket?  and vice
  43         * versa?
  44         */
  45        switch (srx.transport.family) {
  46        case AF_INET:
  47                srx.transport.sin.sin_port = serr->port;
  48                srx.transport_len = sizeof(struct sockaddr_in);
  49                switch (serr->ee.ee_origin) {
  50                case SO_EE_ORIGIN_ICMP:
  51                        _net("Rx ICMP");
  52                        memcpy(&srx.transport.sin.sin_addr,
  53                               skb_network_header(skb) + serr->addr_offset,
  54                               sizeof(struct in_addr));
  55                        break;
  56                case SO_EE_ORIGIN_ICMP6:
  57                        _net("Rx ICMP6 on v4 sock");
  58                        memcpy(&srx.transport.sin.sin_addr,
  59                               skb_network_header(skb) + serr->addr_offset + 12,
  60                               sizeof(struct in_addr));
  61                        break;
  62                default:
  63                        memcpy(&srx.transport.sin.sin_addr, &ip_hdr(skb)->saddr,
  64                               sizeof(struct in_addr));
  65                        break;
  66                }
  67                break;
  68
  69#ifdef CONFIG_AF_RXRPC_IPV6
  70        case AF_INET6:
  71                srx.transport.sin6.sin6_port = serr->port;
  72                srx.transport_len = sizeof(struct sockaddr_in6);
  73                switch (serr->ee.ee_origin) {
  74                case SO_EE_ORIGIN_ICMP6:
  75                        _net("Rx ICMP6");
  76                        memcpy(&srx.transport.sin6.sin6_addr,
  77                               skb_network_header(skb) + serr->addr_offset,
  78                               sizeof(struct in6_addr));
  79                        break;
  80                case SO_EE_ORIGIN_ICMP:
  81                        _net("Rx ICMP on v6 sock");
  82                        memcpy(srx.transport.sin6.sin6_addr.s6_addr + 12,
  83                               skb_network_header(skb) + serr->addr_offset,
  84                               sizeof(struct in_addr));
  85                        break;
  86                default:
  87                        memcpy(&srx.transport.sin6.sin6_addr,
  88                               &ipv6_hdr(skb)->saddr,
  89                               sizeof(struct in6_addr));
  90                        break;
  91                }
  92                break;
  93#endif
  94
  95        default:
  96                BUG();
  97        }
  98
  99        return rxrpc_lookup_peer_rcu(local, &srx);
 100}
 101
 102/*
 103 * Handle an MTU/fragmentation problem.
 104 */
 105static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *serr)
 106{
 107        u32 mtu = serr->ee.ee_info;
 108
 109        _net("Rx ICMP Fragmentation Needed (%d)", mtu);
 110
 111        /* wind down the local interface MTU */
 112        if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
 113                peer->if_mtu = mtu;
 114                _net("I/F MTU %u", mtu);
 115        }
 116
 117        if (mtu == 0) {
 118                /* they didn't give us a size, estimate one */
 119                mtu = peer->if_mtu;
 120                if (mtu > 1500) {
 121                        mtu >>= 1;
 122                        if (mtu < 1500)
 123                                mtu = 1500;
 124                } else {
 125                        mtu -= 100;
 126                        if (mtu < peer->hdrsize)
 127                                mtu = peer->hdrsize + 4;
 128                }
 129        }
 130
 131        if (mtu < peer->mtu) {
 132                spin_lock_bh(&peer->lock);
 133                peer->mtu = mtu;
 134                peer->maxdata = peer->mtu - peer->hdrsize;
 135                spin_unlock_bh(&peer->lock);
 136                _net("Net MTU %u (maxdata %u)",
 137                     peer->mtu, peer->maxdata);
 138        }
 139}
 140
 141/*
 142 * Handle an error received on the local endpoint.
 143 */
 144void rxrpc_error_report(struct sock *sk)
 145{
 146        struct sock_exterr_skb *serr;
 147        struct rxrpc_local *local = sk->sk_user_data;
 148        struct rxrpc_peer *peer;
 149        struct sk_buff *skb;
 150
 151        _enter("%p{%d}", sk, local->debug_id);
 152
 153        skb = sock_dequeue_err_skb(sk);
 154        if (!skb) {
 155                _leave("UDP socket errqueue empty");
 156                return;
 157        }
 158        rxrpc_new_skb(skb, rxrpc_skb_rx_received);
 159        serr = SKB_EXT_ERR(skb);
 160        if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
 161                _leave("UDP empty message");
 162                rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 163                return;
 164        }
 165
 166        rcu_read_lock();
 167        peer = rxrpc_lookup_peer_icmp_rcu(local, skb);
 168        if (peer && !rxrpc_get_peer_maybe(peer))
 169                peer = NULL;
 170        if (!peer) {
 171                rcu_read_unlock();
 172                rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 173                _leave(" [no peer]");
 174                return;
 175        }
 176
 177        if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
 178             serr->ee.ee_type == ICMP_DEST_UNREACH &&
 179             serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
 180                rxrpc_adjust_mtu(peer, serr);
 181                rcu_read_unlock();
 182                rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 183                rxrpc_put_peer(peer);
 184                _leave(" [MTU update]");
 185                return;
 186        }
 187
 188        rxrpc_store_error(peer, serr);
 189        rcu_read_unlock();
 190        rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 191
 192        /* The ref we obtained is passed off to the work item */
 193        rxrpc_queue_work(&peer->error_distributor);
 194        _leave("");
 195}
 196
 197/*
 198 * Map an error report to error codes on the peer record.
 199 */
 200static void rxrpc_store_error(struct rxrpc_peer *peer,
 201                              struct sock_exterr_skb *serr)
 202{
 203        struct sock_extended_err *ee;
 204        int err;
 205
 206        _enter("");
 207
 208        ee = &serr->ee;
 209
 210        _net("Rx Error o=%d t=%d c=%d e=%d",
 211             ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
 212
 213        err = ee->ee_errno;
 214
 215        switch (ee->ee_origin) {
 216        case SO_EE_ORIGIN_ICMP:
 217                switch (ee->ee_type) {
 218                case ICMP_DEST_UNREACH:
 219                        switch (ee->ee_code) {
 220                        case ICMP_NET_UNREACH:
 221                                _net("Rx Received ICMP Network Unreachable");
 222                                break;
 223                        case ICMP_HOST_UNREACH:
 224                                _net("Rx Received ICMP Host Unreachable");
 225                                break;
 226                        case ICMP_PORT_UNREACH:
 227                                _net("Rx Received ICMP Port Unreachable");
 228                                break;
 229                        case ICMP_NET_UNKNOWN:
 230                                _net("Rx Received ICMP Unknown Network");
 231                                break;
 232                        case ICMP_HOST_UNKNOWN:
 233                                _net("Rx Received ICMP Unknown Host");
 234                                break;
 235                        default:
 236                                _net("Rx Received ICMP DestUnreach code=%u",
 237                                     ee->ee_code);
 238                                break;
 239                        }
 240                        break;
 241
 242                case ICMP_TIME_EXCEEDED:
 243                        _net("Rx Received ICMP TTL Exceeded");
 244                        break;
 245
 246                default:
 247                        _proto("Rx Received ICMP error { type=%u code=%u }",
 248                               ee->ee_type, ee->ee_code);
 249                        break;
 250                }
 251                break;
 252
 253        case SO_EE_ORIGIN_NONE:
 254        case SO_EE_ORIGIN_LOCAL:
 255                _proto("Rx Received local error { error=%d }", err);
 256                err += RXRPC_LOCAL_ERROR_OFFSET;
 257                break;
 258
 259        case SO_EE_ORIGIN_ICMP6:
 260        default:
 261                _proto("Rx Received error report { orig=%u }", ee->ee_origin);
 262                break;
 263        }
 264
 265        peer->error_report = err;
 266}
 267
 268/*
 269 * Distribute an error that occurred on a peer
 270 */
 271void rxrpc_peer_error_distributor(struct work_struct *work)
 272{
 273        struct rxrpc_peer *peer =
 274                container_of(work, struct rxrpc_peer, error_distributor);
 275        struct rxrpc_call *call;
 276        enum rxrpc_call_completion compl;
 277        int error;
 278
 279        _enter("");
 280
 281        error = READ_ONCE(peer->error_report);
 282        if (error < RXRPC_LOCAL_ERROR_OFFSET) {
 283                compl = RXRPC_CALL_NETWORK_ERROR;
 284        } else {
 285                compl = RXRPC_CALL_LOCAL_ERROR;
 286                error -= RXRPC_LOCAL_ERROR_OFFSET;
 287        }
 288
 289        _debug("ISSUE ERROR %s %d", rxrpc_call_completions[compl], error);
 290
 291        spin_lock_bh(&peer->lock);
 292
 293        while (!hlist_empty(&peer->error_targets)) {
 294                call = hlist_entry(peer->error_targets.first,
 295                                   struct rxrpc_call, error_link);
 296                hlist_del_init(&call->error_link);
 297                rxrpc_see_call(call);
 298
 299                if (rxrpc_set_call_completion(call, compl, 0, -error))
 300                        rxrpc_notify_socket(call);
 301        }
 302
 303        spin_unlock_bh(&peer->lock);
 304
 305        rxrpc_put_peer(peer);
 306        _leave("");
 307}
 308
 309/*
 310 * Add RTT information to cache.  This is called in softirq mode and has
 311 * exclusive access to the peer RTT data.
 312 */
 313void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
 314                        rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,
 315                        ktime_t send_time, ktime_t resp_time)
 316{
 317        struct rxrpc_peer *peer = call->peer;
 318        s64 rtt;
 319        u64 sum = peer->rtt_sum, avg;
 320        u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage;
 321
 322        rtt = ktime_to_ns(ktime_sub(resp_time, send_time));
 323        if (rtt < 0)
 324                return;
 325
 326        /* Replace the oldest datum in the RTT buffer */
 327        sum -= peer->rtt_cache[cursor];
 328        sum += rtt;
 329        peer->rtt_cache[cursor] = rtt;
 330        peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1);
 331        peer->rtt_sum = sum;
 332        if (usage < RXRPC_RTT_CACHE_SIZE) {
 333                usage++;
 334                peer->rtt_usage = usage;
 335        }
 336
 337        /* Now recalculate the average */
 338        if (usage == RXRPC_RTT_CACHE_SIZE) {
 339                avg = sum / RXRPC_RTT_CACHE_SIZE;
 340        } else {
 341                avg = sum;
 342                do_div(avg, usage);
 343        }
 344
 345        peer->rtt = avg;
 346        trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt,
 347                           usage, avg);
 348}
 349