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 21 static void rxrpc_store_error(struct rxrpc_peer *, struct sock_exterr_skb *); 22 static 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 */ 28 static 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 */ 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 /* 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 */ 209 static 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 */ 278 static 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 */ 295 void 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 */ 340 static 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 */ 390 void 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