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 25 static void rxrpc_store_error(struct rxrpc_peer *, struct sock_exterr_skb *); 26 27 /* 28 * Find the peer associated with an ICMP packet. 29 */ 30 static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local, 31 const struct sk_buff *skb, 32 struct sockaddr_rxrpc *srx) 33 { 34 struct sock_exterr_skb *serr = SKB_EXT_ERR(skb); 35 36 _enter(""); 37 38 memset(srx, 0, sizeof(*srx)); 39 srx->transport_type = local->srx.transport_type; 40 srx->transport_len = local->srx.transport_len; 41 srx->transport.family = local->srx.transport.family; 42 43 /* Can we see an ICMP4 packet on an ICMP6 listening socket? and vice 44 * versa? 45 */ 46 switch (srx->transport.family) { 47 case 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 srx->transport.sin6.sin6_port = serr->port; 72 switch (serr->ee.ee_origin) { 73 case SO_EE_ORIGIN_ICMP6: 74 _net("Rx ICMP6"); 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.sin6.sin6_addr.s6_addr32[0] = 0; 82 srx->transport.sin6.sin6_addr.s6_addr32[1] = 0; 83 srx->transport.sin6.sin6_addr.s6_addr32[2] = htonl(0xffff); 84 memcpy(srx->transport.sin6.sin6_addr.s6_addr + 12, 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 */ 107 static 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 */ 146 void 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 skb = sock_dequeue_err_skb(sk); 157 if (!skb) { 158 _leave("UDP socket errqueue empty"); 159 return; 160 } 161 rxrpc_new_skb(skb, rxrpc_skb_rx_received); 162 serr = SKB_EXT_ERR(skb); 163 if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) { 164 _leave("UDP empty message"); 165 rxrpc_free_skb(skb, rxrpc_skb_rx_freed); 166 return; 167 } 168 169 rcu_read_lock(); 170 peer = rxrpc_lookup_peer_icmp_rcu(local, skb, &srx); 171 if (peer && !rxrpc_get_peer_maybe(peer)) 172 peer = NULL; 173 if (!peer) { 174 rcu_read_unlock(); 175 rxrpc_free_skb(skb, rxrpc_skb_rx_freed); 176 _leave(" [no peer]"); 177 return; 178 } 179 180 trace_rxrpc_rx_icmp(peer, &serr->ee, &srx); 181 182 if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP && 183 serr->ee.ee_type == ICMP_DEST_UNREACH && 184 serr->ee.ee_code == ICMP_FRAG_NEEDED)) { 185 rxrpc_adjust_mtu(peer, serr); 186 rcu_read_unlock(); 187 rxrpc_free_skb(skb, rxrpc_skb_rx_freed); 188 rxrpc_put_peer(peer); 189 _leave(" [MTU update]"); 190 return; 191 } 192 193 rxrpc_store_error(peer, serr); 194 rcu_read_unlock(); 195 rxrpc_free_skb(skb, rxrpc_skb_rx_freed); 196 197 /* The ref we obtained is passed off to the work item */ 198 __rxrpc_queue_peer_error(peer); 199 _leave(""); 200 } 201 202 /* 203 * Map an error report to error codes on the peer record. 204 */ 205 static void rxrpc_store_error(struct rxrpc_peer *peer, 206 struct sock_exterr_skb *serr) 207 { 208 struct sock_extended_err *ee; 209 int err; 210 211 _enter(""); 212 213 ee = &serr->ee; 214 215 err = ee->ee_errno; 216 217 switch (ee->ee_origin) { 218 case SO_EE_ORIGIN_ICMP: 219 switch (ee->ee_type) { 220 case ICMP_DEST_UNREACH: 221 switch (ee->ee_code) { 222 case ICMP_NET_UNREACH: 223 _net("Rx Received ICMP Network Unreachable"); 224 break; 225 case ICMP_HOST_UNREACH: 226 _net("Rx Received ICMP Host Unreachable"); 227 break; 228 case ICMP_PORT_UNREACH: 229 _net("Rx Received ICMP Port Unreachable"); 230 break; 231 case ICMP_NET_UNKNOWN: 232 _net("Rx Received ICMP Unknown Network"); 233 break; 234 case ICMP_HOST_UNKNOWN: 235 _net("Rx Received ICMP Unknown Host"); 236 break; 237 default: 238 _net("Rx Received ICMP DestUnreach code=%u", 239 ee->ee_code); 240 break; 241 } 242 break; 243 244 case ICMP_TIME_EXCEEDED: 245 _net("Rx Received ICMP TTL Exceeded"); 246 break; 247 248 default: 249 _proto("Rx Received ICMP error { type=%u code=%u }", 250 ee->ee_type, ee->ee_code); 251 break; 252 } 253 break; 254 255 case SO_EE_ORIGIN_NONE: 256 case SO_EE_ORIGIN_LOCAL: 257 _proto("Rx Received local error { error=%d }", err); 258 err += RXRPC_LOCAL_ERROR_OFFSET; 259 break; 260 261 case SO_EE_ORIGIN_ICMP6: 262 default: 263 _proto("Rx Received error report { orig=%u }", ee->ee_origin); 264 break; 265 } 266 267 peer->error_report = err; 268 } 269 270 /* 271 * Distribute an error that occurred on a peer 272 */ 273 void rxrpc_peer_error_distributor(struct work_struct *work) 274 { 275 struct rxrpc_peer *peer = 276 container_of(work, struct rxrpc_peer, error_distributor); 277 struct rxrpc_call *call; 278 enum rxrpc_call_completion compl; 279 int error; 280 281 _enter(""); 282 283 error = READ_ONCE(peer->error_report); 284 if (error < RXRPC_LOCAL_ERROR_OFFSET) { 285 compl = RXRPC_CALL_NETWORK_ERROR; 286 } else { 287 compl = RXRPC_CALL_LOCAL_ERROR; 288 error -= RXRPC_LOCAL_ERROR_OFFSET; 289 } 290 291 _debug("ISSUE ERROR %s %d", rxrpc_call_completions[compl], error); 292 293 spin_lock_bh(&peer->lock); 294 295 while (!hlist_empty(&peer->error_targets)) { 296 call = hlist_entry(peer->error_targets.first, 297 struct rxrpc_call, error_link); 298 hlist_del_init(&call->error_link); 299 rxrpc_see_call(call); 300 301 if (rxrpc_set_call_completion(call, compl, 0, -error)) 302 rxrpc_notify_socket(call); 303 } 304 305 spin_unlock_bh(&peer->lock); 306 307 rxrpc_put_peer(peer); 308 _leave(""); 309 } 310 311 /* 312 * Add RTT information to cache. This is called in softirq mode and has 313 * exclusive access to the peer RTT data. 314 */ 315 void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why, 316 rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial, 317 ktime_t send_time, ktime_t resp_time) 318 { 319 struct rxrpc_peer *peer = call->peer; 320 s64 rtt; 321 u64 sum = peer->rtt_sum, avg; 322 u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage; 323 324 rtt = ktime_to_ns(ktime_sub(resp_time, send_time)); 325 if (rtt < 0) 326 return; 327 328 /* Replace the oldest datum in the RTT buffer */ 329 sum -= peer->rtt_cache[cursor]; 330 sum += rtt; 331 peer->rtt_cache[cursor] = rtt; 332 peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1); 333 peer->rtt_sum = sum; 334 if (usage < RXRPC_RTT_CACHE_SIZE) { 335 usage++; 336 peer->rtt_usage = usage; 337 } 338 339 /* Now recalculate the average */ 340 if (usage == RXRPC_RTT_CACHE_SIZE) { 341 avg = sum / RXRPC_RTT_CACHE_SIZE; 342 } else { 343 avg = sum; 344 do_div(avg, usage); 345 } 346 347 peer->rtt = avg; 348 trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt, 349 usage, avg); 350 } 351 352 /* 353 * Perform keep-alive pings. 354 */ 355 static void rxrpc_peer_keepalive_dispatch(struct rxrpc_net *rxnet, 356 struct list_head *collector, 357 time64_t base, 358 u8 cursor) 359 { 360 struct rxrpc_peer *peer; 361 const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1; 362 time64_t keepalive_at; 363 int slot; 364 365 spin_lock_bh(&rxnet->peer_hash_lock); 366 367 while (!list_empty(collector)) { 368 peer = list_entry(collector->next, 369 struct rxrpc_peer, keepalive_link); 370 371 list_del_init(&peer->keepalive_link); 372 if (!rxrpc_get_peer_maybe(peer)) 373 continue; 374 375 spin_unlock_bh(&rxnet->peer_hash_lock); 376 377 keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME; 378 slot = keepalive_at - base; 379 _debug("%02x peer %u t=%d {%pISp}", 380 cursor, peer->debug_id, slot, &peer->srx.transport); 381 382 if (keepalive_at <= base || 383 keepalive_at > base + RXRPC_KEEPALIVE_TIME) { 384 rxrpc_send_keepalive(peer); 385 slot = RXRPC_KEEPALIVE_TIME; 386 } 387 388 /* A transmission to this peer occurred since last we examined 389 * it so put it into the appropriate future bucket. 390 */ 391 slot += cursor; 392 slot &= mask; 393 spin_lock_bh(&rxnet->peer_hash_lock); 394 list_add_tail(&peer->keepalive_link, 395 &rxnet->peer_keepalive[slot & mask]); 396 rxrpc_put_peer(peer); 397 } 398 399 spin_unlock_bh(&rxnet->peer_hash_lock); 400 } 401 402 /* 403 * Perform keep-alive pings with VERSION packets to keep any NAT alive. 404 */ 405 void rxrpc_peer_keepalive_worker(struct work_struct *work) 406 { 407 struct rxrpc_net *rxnet = 408 container_of(work, struct rxrpc_net, peer_keepalive_work); 409 const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1; 410 time64_t base, now, delay; 411 u8 cursor, stop; 412 LIST_HEAD(collector); 413 414 now = ktime_get_seconds(); 415 base = rxnet->peer_keepalive_base; 416 cursor = rxnet->peer_keepalive_cursor; 417 _enter("%lld,%u", base - now, cursor); 418 419 if (!rxnet->live) 420 return; 421 422 /* Remove to a temporary list all the peers that are currently lodged 423 * in expired buckets plus all new peers. 424 * 425 * Everything in the bucket at the cursor is processed this 426 * second; the bucket at cursor + 1 goes at now + 1s and so 427 * on... 428 */ 429 spin_lock_bh(&rxnet->peer_hash_lock); 430 list_splice_init(&rxnet->peer_keepalive_new, &collector); 431 432 stop = cursor + ARRAY_SIZE(rxnet->peer_keepalive); 433 while (base <= now && (s8)(cursor - stop) < 0) { 434 list_splice_tail_init(&rxnet->peer_keepalive[cursor & mask], 435 &collector); 436 base++; 437 cursor++; 438 } 439 440 base = now; 441 spin_unlock_bh(&rxnet->peer_hash_lock); 442 443 rxnet->peer_keepalive_base = base; 444 rxnet->peer_keepalive_cursor = cursor; 445 rxrpc_peer_keepalive_dispatch(rxnet, &collector, base, cursor); 446 ASSERT(list_empty(&collector)); 447 448 /* Schedule the timer for the next occupied timeslot. */ 449 cursor = rxnet->peer_keepalive_cursor; 450 stop = cursor + RXRPC_KEEPALIVE_TIME - 1; 451 for (; (s8)(cursor - stop) < 0; cursor++) { 452 if (!list_empty(&rxnet->peer_keepalive[cursor & mask])) 453 break; 454 base++; 455 } 456 457 now = ktime_get_seconds(); 458 delay = base - now; 459 if (delay < 1) 460 delay = 1; 461 delay *= HZ; 462 if (rxnet->live) 463 timer_reduce(&rxnet->peer_keepalive_timer, jiffies + delay); 464 465 _leave(""); 466 } 467