LXR linux/net/rxrpc/peer

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/* Peer event handling, typically ICMP messages.
   3 *
   4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   5 * Written by David Howells (dhowells@redhat.com)
   6 */
   7
   8#include <linux/module.h>
   9#include <linux/net.h>
  10#include <linux/skbuff.h>
  11#include <linux/errqueue.h>
  12#include <linux/udp.h>
  13#include <linux/in.h>
  14#include <linux/in6.h>
  15#include <linux/icmp.h>
  16#include <net/sock.h>
  17#include <net/af_rxrpc.h>
  18#include <net/ip.h>
  19#include "ar-internal.h"
  20
  21static void rxrpc_store_error(struct rxrpc_peer *, struct sock_exterr_skb *);
  22static void rxrpc_distribute_error(struct rxrpc_peer *, int,
  23                                   enum rxrpc_call_completion);
  24
  25/*
  26 * Find the peer associated with an ICMP packet.
  27 */
  28static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local,
  29                                                     const struct sk_buff *skb,
  30                                                     struct sockaddr_rxrpc *srx)
  31{
  32        struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
  33
  34        _enter("");
  35
  36        memset(srx, 0, sizeof(*srx));
  37        srx->transport_type = local->srx.transport_type;
  38        srx->transport_len = local->srx.transport_len;
  39        srx->transport.family = local->srx.transport.family;
  40
  41        /* Can we see an ICMP4 packet on an ICMP6 listening socket?  and vice
  42         * versa?
  43         */
  44        switch (srx->transport.family) {
  45        case AF_INET:
  46                srx->transport_len = sizeof(srx->transport.sin);
  47                srx->transport.family = AF_INET;
  48                srx->transport.sin.sin_port = serr->port;
  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                switch (serr->ee.ee_origin) {
  72                case SO_EE_ORIGIN_ICMP6:
  73                        _net("Rx ICMP6");
  74                        srx->transport.sin6.sin6_port = serr->port;
  75                        memcpy(&srx->transport.sin6.sin6_addr,
  76                               skb_network_header(skb) + serr->addr_offset,
  77                               sizeof(struct in6_addr));
  78                        break;
  79                case SO_EE_ORIGIN_ICMP:
  80                        _net("Rx ICMP on v6 sock");
  81                        srx->transport_len = sizeof(srx->transport.sin);
  82                        srx->transport.family = AF_INET;
  83                        srx->transport.sin.sin_port = serr->port;
  84                        memcpy(&srx->transport.sin.sin_addr,
  85                               skb_network_header(skb) + serr->addr_offset,
  86                               sizeof(struct in_addr));
  87                        break;
  88                default:
  89                        memcpy(&srx->transport.sin6.sin6_addr,
  90                               &ipv6_hdr(skb)->saddr,
  91                               sizeof(struct in6_addr));
  92                        break;
  93                }
  94                break;
  95#endif
  96
  97        default:
  98                BUG();
  99        }
 100
 101        return rxrpc_lookup_peer_rcu(local, srx);
 102}
 103
 104/*
 105 * Handle an MTU/fragmentation problem.
 106 */
 107static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *serr)
 108{
 109        u32 mtu = serr->ee.ee_info;
 110
 111        _net("Rx ICMP Fragmentation Needed (%d)", mtu);
 112
 113        /* wind down the local interface MTU */
 114        if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
 115                peer->if_mtu = mtu;
 116                _net("I/F MTU %u", mtu);
 117        }
 118
 119        if (mtu == 0) {
 120                /* they didn't give us a size, estimate one */
 121                mtu = peer->if_mtu;
 122                if (mtu > 1500) {
 123                        mtu >>= 1;
 124                        if (mtu < 1500)
 125                                mtu = 1500;
 126                } else {
 127                        mtu -= 100;
 128                        if (mtu < peer->hdrsize)
 129                                mtu = peer->hdrsize + 4;
 130                }
 131        }
 132
 133        if (mtu < peer->mtu) {
 134                spin_lock_bh(&peer->lock);
 135                peer->mtu = mtu;
 136                peer->maxdata = peer->mtu - peer->hdrsize;
 137                spin_unlock_bh(&peer->lock);
 138                _net("Net MTU %u (maxdata %u)",
 139                     peer->mtu, peer->maxdata);
 140        }
 141}
 142
 143/*
 144 * Handle an error received on the local endpoint.
 145 */
 146void rxrpc_error_report(struct sock *sk)
 147{
 148        struct sock_exterr_skb *serr;
 149        struct sockaddr_rxrpc srx;
 150        struct rxrpc_local *local = sk->sk_user_data;
 151        struct rxrpc_peer *peer;
 152        struct sk_buff *skb;
 153
 154        _enter("%p{%d}", sk, local->debug_id);
 155
 156        /* Clear the outstanding error value on the socket so that it doesn't
 157         * cause kernel_sendmsg() to return it later.
 158         */
 159        sock_error(sk);
 160
 161        skb = sock_dequeue_err_skb(sk);
 162        if (!skb) {
 163                _leave("UDP socket errqueue empty");
 164                return;
 165        }
 166        rxrpc_new_skb(skb, rxrpc_skb_rx_received);
 167        serr = SKB_EXT_ERR(skb);
 168        if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
 169                _leave("UDP empty message");
 170                rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 171                return;
 172        }
 173
 174        rcu_read_lock();
 175        peer = rxrpc_lookup_peer_icmp_rcu(local, skb, &srx);
 176        if (peer && !rxrpc_get_peer_maybe(peer))
 177                peer = NULL;
 178        if (!peer) {
 179                rcu_read_unlock();
 180                rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 181                _leave(" [no peer]");
 182                return;
 183        }
 184
 185        trace_rxrpc_rx_icmp(peer, &serr->ee, &srx);
 186
 187        if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
 188             serr->ee.ee_type == ICMP_DEST_UNREACH &&
 189             serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
 190                rxrpc_adjust_mtu(peer, serr);
 191                rcu_read_unlock();
 192                rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 193                rxrpc_put_peer(peer);
 194                _leave(" [MTU update]");
 195                return;
 196        }
 197
 198        rxrpc_store_error(peer, serr);
 199        rcu_read_unlock();
 200        rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
 201        rxrpc_put_peer(peer);
 202
 203        _leave("");
 204}
 205
 206/*
 207 * Map an error report to error codes on the peer record.
 208 */
 209static void rxrpc_store_error(struct rxrpc_peer *peer,
 210                              struct sock_exterr_skb *serr)
 211{
 212        enum rxrpc_call_completion compl = RXRPC_CALL_NETWORK_ERROR;
 213        struct sock_extended_err *ee;
 214        int err;
 215
 216        _enter("");
 217
 218        ee = &serr->ee;
 219
 220        err = ee->ee_errno;
 221
 222        switch (ee->ee_origin) {
 223        case SO_EE_ORIGIN_ICMP:
 224                switch (ee->ee_type) {
 225                case ICMP_DEST_UNREACH:
 226                        switch (ee->ee_code) {
 227                        case ICMP_NET_UNREACH:
 228                                _net("Rx Received ICMP Network Unreachable");
 229                                break;
 230                        case ICMP_HOST_UNREACH:
 231                                _net("Rx Received ICMP Host Unreachable");
 232                                break;
 233                        case ICMP_PORT_UNREACH:
 234                                _net("Rx Received ICMP Port Unreachable");
 235                                break;
 236                        case ICMP_NET_UNKNOWN:
 237                                _net("Rx Received ICMP Unknown Network");
 238                                break;
 239                        case ICMP_HOST_UNKNOWN:
 240                                _net("Rx Received ICMP Unknown Host");
 241                                break;
 242                        default:
 243                                _net("Rx Received ICMP DestUnreach code=%u",
 244                                     ee->ee_code);
 245                                break;
 246                        }
 247                        break;
 248
 249                case ICMP_TIME_EXCEEDED:
 250                        _net("Rx Received ICMP TTL Exceeded");
 251                        break;
 252
 253                default:
 254                        _proto("Rx Received ICMP error { type=%u code=%u }",
 255                               ee->ee_type, ee->ee_code);
 256                        break;
 257                }
 258                break;
 259
 260        case SO_EE_ORIGIN_NONE:
 261        case SO_EE_ORIGIN_LOCAL:
 262                _proto("Rx Received local error { error=%d }", err);
 263                compl = RXRPC_CALL_LOCAL_ERROR;
 264                break;
 265
 266        case SO_EE_ORIGIN_ICMP6:
 267        default:
 268                _proto("Rx Received error report { orig=%u }", ee->ee_origin);
 269                break;
 270        }
 271
 272        rxrpc_distribute_error(peer, err, compl);
 273}
 274
 275/*
 276 * Distribute an error that occurred on a peer.
 277 */
 278static void rxrpc_distribute_error(struct rxrpc_peer *peer, int error,
 279                                   enum rxrpc_call_completion compl)
 280{
 281        struct rxrpc_call *call;
 282
 283        hlist_for_each_entry_rcu(call, &peer->error_targets, error_link) {
 284                rxrpc_see_call(call);
 285                if (call->state < RXRPC_CALL_COMPLETE &&
 286                    rxrpc_set_call_completion(call, compl, 0, -error))
 287                        rxrpc_notify_socket(call);
 288        }
 289}
 290
 291/*
 292 * Add RTT information to cache.  This is called in softirq mode and has
 293 * exclusive access to the peer RTT data.
 294 */
 295void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
 296                        rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,
 297                        ktime_t send_time, ktime_t resp_time)
 298{
 299        struct rxrpc_peer *peer = call->peer;
 300        s64 rtt;
 301        u64 sum = peer->rtt_sum, avg;
 302        u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage;
 303
 304        rtt = ktime_to_ns(ktime_sub(resp_time, send_time));
 305        if (rtt < 0)
 306                return;
 307
 308        spin_lock(&peer->rtt_input_lock);
 309
 310        /* Replace the oldest datum in the RTT buffer */
 311        sum -= peer->rtt_cache[cursor];
 312        sum += rtt;
 313        peer->rtt_cache[cursor] = rtt;
 314        peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1);
 315        peer->rtt_sum = sum;
 316        if (usage < RXRPC_RTT_CACHE_SIZE) {
 317                usage++;
 318                peer->rtt_usage = usage;
 319        }
 320
 321        spin_unlock(&peer->rtt_input_lock);
 322
 323        /* Now recalculate the average */
 324        if (usage == RXRPC_RTT_CACHE_SIZE) {
 325                avg = sum / RXRPC_RTT_CACHE_SIZE;
 326        } else {
 327                avg = sum;
 328                do_div(avg, usage);
 329        }
 330
 331        /* Don't need to update this under lock */
 332        peer->rtt = avg;
 333        trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt,
 334                           usage, avg);
 335}
 336
 337/*
 338 * Perform keep-alive pings.
 339 */
 340static void rxrpc_peer_keepalive_dispatch(struct rxrpc_net *rxnet,
 341                                          struct list_head *collector,
 342                                          time64_t base,
 343                                          u8 cursor)
 344{
 345        struct rxrpc_peer *peer;
 346        const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1;
 347        time64_t keepalive_at;
 348        int slot;
 349
 350        spin_lock_bh(&rxnet->peer_hash_lock);
 351
 352        while (!list_empty(collector)) {
 353                peer = list_entry(collector->next,
 354                                  struct rxrpc_peer, keepalive_link);
 355
 356                list_del_init(&peer->keepalive_link);
 357                if (!rxrpc_get_peer_maybe(peer))
 358                        continue;
 359
 360                spin_unlock_bh(&rxnet->peer_hash_lock);
 361
 362                keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME;
 363                slot = keepalive_at - base;
 364                _debug("%02x peer %u t=%d {%pISp}",
 365                       cursor, peer->debug_id, slot, &peer->srx.transport);
 366
 367                if (keepalive_at <= base ||
 368                    keepalive_at > base + RXRPC_KEEPALIVE_TIME) {
 369                        rxrpc_send_keepalive(peer);
 370                        slot = RXRPC_KEEPALIVE_TIME;
 371                }
 372
 373                /* A transmission to this peer occurred since last we examined
 374                 * it so put it into the appropriate future bucket.
 375                 */
 376                slot += cursor;
 377                slot &= mask;
 378                spin_lock_bh(&rxnet->peer_hash_lock);
 379                list_add_tail(&peer->keepalive_link,
 380                              &rxnet->peer_keepalive[slot & mask]);
 381                rxrpc_put_peer(peer);
 382        }
 383
 384        spin_unlock_bh(&rxnet->peer_hash_lock);
 385}
 386
 387/*
 388 * Perform keep-alive pings with VERSION packets to keep any NAT alive.
 389 */
 390void rxrpc_peer_keepalive_worker(struct work_struct *work)
 391{
 392        struct rxrpc_net *rxnet =
 393                container_of(work, struct rxrpc_net, peer_keepalive_work);
 394        const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1;
 395        time64_t base, now, delay;
 396        u8 cursor, stop;
 397        LIST_HEAD(collector);
 398
 399        now = ktime_get_seconds();
 400        base = rxnet->peer_keepalive_base;
 401        cursor = rxnet->peer_keepalive_cursor;
 402        _enter("%lld,%u", base - now, cursor);
 403
 404        if (!rxnet->live)
 405                return;
 406
 407        /* Remove to a temporary list all the peers that are currently lodged
 408         * in expired buckets plus all new peers.
 409         *
 410         * Everything in the bucket at the cursor is processed this
 411         * second; the bucket at cursor + 1 goes at now + 1s and so
 412         * on...
 413         */
 414        spin_lock_bh(&rxnet->peer_hash_lock);
 415        list_splice_init(&rxnet->peer_keepalive_new, &collector);
 416
 417        stop = cursor + ARRAY_SIZE(rxnet->peer_keepalive);
 418        while (base <= now && (s8)(cursor - stop) < 0) {
 419                list_splice_tail_init(&rxnet->peer_keepalive[cursor & mask],
 420                                      &collector);
 421                base++;
 422                cursor++;
 423        }
 424
 425        base = now;
 426        spin_unlock_bh(&rxnet->peer_hash_lock);
 427
 428        rxnet->peer_keepalive_base = base;
 429        rxnet->peer_keepalive_cursor = cursor;
 430        rxrpc_peer_keepalive_dispatch(rxnet, &collector, base, cursor);
 431        ASSERT(list_empty(&collector));
 432
 433        /* Schedule the timer for the next occupied timeslot. */
 434        cursor = rxnet->peer_keepalive_cursor;
 435        stop = cursor + RXRPC_KEEPALIVE_TIME - 1;
 436        for (; (s8)(cursor - stop) < 0; cursor++) {
 437                if (!list_empty(&rxnet->peer_keepalive[cursor & mask]))
 438                        break;
 439                base++;
 440        }
 441
 442        now = ktime_get_seconds();
 443        delay = base - now;
 444        if (delay < 1)
 445                delay = 1;
 446        delay *= HZ;
 447        if (rxnet->live)
 448                timer_reduce(&rxnet->peer_keepalive_timer, jiffies + delay);
 449
 450        _leave("");
 451}
 452