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 static void rxrpc_distribute_error(struct rxrpc_peer *, int, 27 enum rxrpc_call_completion); 28 29 /* 30 * Find the peer associated with an ICMP packet. 31 */ 32 static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local, 33 const struct sk_buff *skb, 34 struct sockaddr_rxrpc *srx) 35 { 36 struct sock_exterr_skb *serr = SKB_EXT_ERR(skb); 37 38 _enter(""); 39 40 memset(srx, 0, sizeof(*srx)); 41 srx->transport_type = local->srx.transport_type; 42 srx->transport_len = local->srx.transport_len; 43 srx->transport.family = local->srx.transport.family; 44 45 /* Can we see an ICMP4 packet on an ICMP6 listening socket? and vice 46 * versa? 47 */ 48 switch (srx->transport.family) { 49 case AF_INET: 50 srx->transport.sin.sin_port = serr->port; 51 switch (serr->ee.ee_origin) { 52 case SO_EE_ORIGIN_ICMP: 53 _net("Rx ICMP"); 54 memcpy(&srx->transport.sin.sin_addr, 55 skb_network_header(skb) + serr->addr_offset, 56 sizeof(struct in_addr)); 57 break; 58 case SO_EE_ORIGIN_ICMP6: 59 _net("Rx ICMP6 on v4 sock"); 60 memcpy(&srx->transport.sin.sin_addr, 61 skb_network_header(skb) + serr->addr_offset + 12, 62 sizeof(struct in_addr)); 63 break; 64 default: 65 memcpy(&srx->transport.sin.sin_addr, &ip_hdr(skb)->saddr, 66 sizeof(struct in_addr)); 67 break; 68 } 69 break; 70 71 #ifdef CONFIG_AF_RXRPC_IPV6 72 case AF_INET6: 73 srx->transport.sin6.sin6_port = serr->port; 74 switch (serr->ee.ee_origin) { 75 case SO_EE_ORIGIN_ICMP6: 76 _net("Rx ICMP6"); 77 memcpy(&srx->transport.sin6.sin6_addr, 78 skb_network_header(skb) + serr->addr_offset, 79 sizeof(struct in6_addr)); 80 break; 81 case SO_EE_ORIGIN_ICMP: 82 _net("Rx ICMP on v6 sock"); 83 srx->transport.sin6.sin6_addr.s6_addr32[0] = 0; 84 srx->transport.sin6.sin6_addr.s6_addr32[1] = 0; 85 srx->transport.sin6.sin6_addr.s6_addr32[2] = htonl(0xffff); 86 memcpy(srx->transport.sin6.sin6_addr.s6_addr + 12, 87 skb_network_header(skb) + serr->addr_offset, 88 sizeof(struct in_addr)); 89 break; 90 default: 91 memcpy(&srx->transport.sin6.sin6_addr, 92 &ipv6_hdr(skb)->saddr, 93 sizeof(struct in6_addr)); 94 break; 95 } 96 break; 97 #endif 98 99 default: 100 BUG(); 101 } 102 103 return rxrpc_lookup_peer_rcu(local, srx); 104 } 105 106 /* 107 * Handle an MTU/fragmentation problem. 108 */ 109 static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *serr) 110 { 111 u32 mtu = serr->ee.ee_info; 112 113 _net("Rx ICMP Fragmentation Needed (%d)", mtu); 114 115 /* wind down the local interface MTU */ 116 if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) { 117 peer->if_mtu = mtu; 118 _net("I/F MTU %u", mtu); 119 } 120 121 if (mtu == 0) { 122 /* they didn't give us a size, estimate one */ 123 mtu = peer->if_mtu; 124 if (mtu > 1500) { 125 mtu >>= 1; 126 if (mtu < 1500) 127 mtu = 1500; 128 } else { 129 mtu -= 100; 130 if (mtu < peer->hdrsize) 131 mtu = peer->hdrsize + 4; 132 } 133 } 134 135 if (mtu < peer->mtu) { 136 spin_lock_bh(&peer->lock); 137 peer->mtu = mtu; 138 peer->maxdata = peer->mtu - peer->hdrsize; 139 spin_unlock_bh(&peer->lock); 140 _net("Net MTU %u (maxdata %u)", 141 peer->mtu, peer->maxdata); 142 } 143 } 144 145 /* 146 * Handle an error received on the local endpoint. 147 */ 148 void rxrpc_error_report(struct sock *sk) 149 { 150 struct sock_exterr_skb *serr; 151 struct sockaddr_rxrpc srx; 152 struct rxrpc_local *local = sk->sk_user_data; 153 struct rxrpc_peer *peer; 154 struct sk_buff *skb; 155 156 _enter("%p{%d}", sk, local->debug_id); 157 158 skb = sock_dequeue_err_skb(sk); 159 if (!skb) { 160 _leave("UDP socket errqueue empty"); 161 return; 162 } 163 rxrpc_new_skb(skb, rxrpc_skb_rx_received); 164 serr = SKB_EXT_ERR(skb); 165 if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) { 166 _leave("UDP empty message"); 167 rxrpc_free_skb(skb, rxrpc_skb_rx_freed); 168 return; 169 } 170 171 rcu_read_lock(); 172 peer = rxrpc_lookup_peer_icmp_rcu(local, skb, &srx); 173 if (peer && !rxrpc_get_peer_maybe(peer)) 174 peer = NULL; 175 if (!peer) { 176 rcu_read_unlock(); 177 rxrpc_free_skb(skb, rxrpc_skb_rx_freed); 178 _leave(" [no peer]"); 179 return; 180 } 181 182 trace_rxrpc_rx_icmp(peer, &serr->ee, &srx); 183 184 if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP && 185 serr->ee.ee_type == ICMP_DEST_UNREACH && 186 serr->ee.ee_code == ICMP_FRAG_NEEDED)) { 187 rxrpc_adjust_mtu(peer, serr); 188 rcu_read_unlock(); 189 rxrpc_free_skb(skb, rxrpc_skb_rx_freed); 190 rxrpc_put_peer(peer); 191 _leave(" [MTU update]"); 192 return; 193 } 194 195 rxrpc_store_error(peer, serr); 196 rcu_read_unlock(); 197 rxrpc_free_skb(skb, rxrpc_skb_rx_freed); 198 rxrpc_put_peer(peer); 199 200 _leave(""); 201 } 202 203 /* 204 * Map an error report to error codes on the peer record. 205 */ 206 static void rxrpc_store_error(struct rxrpc_peer *peer, 207 struct sock_exterr_skb *serr) 208 { 209 enum rxrpc_call_completion compl = RXRPC_CALL_NETWORK_ERROR; 210 struct sock_extended_err *ee; 211 int err; 212 213 _enter(""); 214 215 ee = &serr->ee; 216 217 err = ee->ee_errno; 218 219 switch (ee->ee_origin) { 220 case SO_EE_ORIGIN_ICMP: 221 switch (ee->ee_type) { 222 case ICMP_DEST_UNREACH: 223 switch (ee->ee_code) { 224 case ICMP_NET_UNREACH: 225 _net("Rx Received ICMP Network Unreachable"); 226 break; 227 case ICMP_HOST_UNREACH: 228 _net("Rx Received ICMP Host Unreachable"); 229 break; 230 case ICMP_PORT_UNREACH: 231 _net("Rx Received ICMP Port Unreachable"); 232 break; 233 case ICMP_NET_UNKNOWN: 234 _net("Rx Received ICMP Unknown Network"); 235 break; 236 case ICMP_HOST_UNKNOWN: 237 _net("Rx Received ICMP Unknown Host"); 238 break; 239 default: 240 _net("Rx Received ICMP DestUnreach code=%u", 241 ee->ee_code); 242 break; 243 } 244 break; 245 246 case ICMP_TIME_EXCEEDED: 247 _net("Rx Received ICMP TTL Exceeded"); 248 break; 249 250 default: 251 _proto("Rx Received ICMP error { type=%u code=%u }", 252 ee->ee_type, ee->ee_code); 253 break; 254 } 255 break; 256 257 case SO_EE_ORIGIN_NONE: 258 case SO_EE_ORIGIN_LOCAL: 259 _proto("Rx Received local error { error=%d }", err); 260 compl = RXRPC_CALL_LOCAL_ERROR; 261 break; 262 263 case SO_EE_ORIGIN_ICMP6: 264 default: 265 _proto("Rx Received error report { orig=%u }", ee->ee_origin); 266 break; 267 } 268 269 rxrpc_distribute_error(peer, err, compl); 270 } 271 272 /* 273 * Distribute an error that occurred on a peer. 274 */ 275 static void rxrpc_distribute_error(struct rxrpc_peer *peer, int error, 276 enum rxrpc_call_completion compl) 277 { 278 struct rxrpc_call *call; 279 280 hlist_for_each_entry_rcu(call, &peer->error_targets, error_link) { 281 rxrpc_see_call(call); 282 if (call->state < RXRPC_CALL_COMPLETE && 283 rxrpc_set_call_completion(call, compl, 0, -error)) 284 rxrpc_notify_socket(call); 285 } 286 } 287 288 /* 289 * Add RTT information to cache. This is called in softirq mode and has 290 * exclusive access to the peer RTT data. 291 */ 292 void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why, 293 rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial, 294 ktime_t send_time, ktime_t resp_time) 295 { 296 struct rxrpc_peer *peer = call->peer; 297 s64 rtt; 298 u64 sum = peer->rtt_sum, avg; 299 u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage; 300 301 rtt = ktime_to_ns(ktime_sub(resp_time, send_time)); 302 if (rtt < 0) 303 return; 304 305 spin_lock(&peer->rtt_input_lock); 306 307 /* Replace the oldest datum in the RTT buffer */ 308 sum -= peer->rtt_cache[cursor]; 309 sum += rtt; 310 peer->rtt_cache[cursor] = rtt; 311 peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1); 312 peer->rtt_sum = sum; 313 if (usage < RXRPC_RTT_CACHE_SIZE) { 314 usage++; 315 peer->rtt_usage = usage; 316 } 317 318 spin_unlock(&peer->rtt_input_lock); 319 320 /* Now recalculate the average */ 321 if (usage == RXRPC_RTT_CACHE_SIZE) { 322 avg = sum / RXRPC_RTT_CACHE_SIZE; 323 } else { 324 avg = sum; 325 do_div(avg, usage); 326 } 327 328 /* Don't need to update this under lock */ 329 peer->rtt = avg; 330 trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt, 331 usage, avg); 332 } 333 334 /* 335 * Perform keep-alive pings. 336 */ 337 static void rxrpc_peer_keepalive_dispatch(struct rxrpc_net *rxnet, 338 struct list_head *collector, 339 time64_t base, 340 u8 cursor) 341 { 342 struct rxrpc_peer *peer; 343 const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1; 344 time64_t keepalive_at; 345 int slot; 346 347 spin_lock_bh(&rxnet->peer_hash_lock); 348 349 while (!list_empty(collector)) { 350 peer = list_entry(collector->next, 351 struct rxrpc_peer, keepalive_link); 352 353 list_del_init(&peer->keepalive_link); 354 if (!rxrpc_get_peer_maybe(peer)) 355 continue; 356 357 spin_unlock_bh(&rxnet->peer_hash_lock); 358 359 keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME; 360 slot = keepalive_at - base; 361 _debug("%02x peer %u t=%d {%pISp}", 362 cursor, peer->debug_id, slot, &peer->srx.transport); 363 364 if (keepalive_at <= base || 365 keepalive_at > base + RXRPC_KEEPALIVE_TIME) { 366 rxrpc_send_keepalive(peer); 367 slot = RXRPC_KEEPALIVE_TIME; 368 } 369 370 /* A transmission to this peer occurred since last we examined 371 * it so put it into the appropriate future bucket. 372 */ 373 slot += cursor; 374 slot &= mask; 375 spin_lock_bh(&rxnet->peer_hash_lock); 376 list_add_tail(&peer->keepalive_link, 377 &rxnet->peer_keepalive[slot & mask]); 378 rxrpc_put_peer(peer); 379 } 380 381 spin_unlock_bh(&rxnet->peer_hash_lock); 382 } 383 384 /* 385 * Perform keep-alive pings with VERSION packets to keep any NAT alive. 386 */ 387 void rxrpc_peer_keepalive_worker(struct work_struct *work) 388 { 389 struct rxrpc_net *rxnet = 390 container_of(work, struct rxrpc_net, peer_keepalive_work); 391 const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1; 392 time64_t base, now, delay; 393 u8 cursor, stop; 394 LIST_HEAD(collector); 395 396 now = ktime_get_seconds(); 397 base = rxnet->peer_keepalive_base; 398 cursor = rxnet->peer_keepalive_cursor; 399 _enter("%lld,%u", base - now, cursor); 400 401 if (!rxnet->live) 402 return; 403 404 /* Remove to a temporary list all the peers that are currently lodged 405 * in expired buckets plus all new peers. 406 * 407 * Everything in the bucket at the cursor is processed this 408 * second; the bucket at cursor + 1 goes at now + 1s and so 409 * on... 410 */ 411 spin_lock_bh(&rxnet->peer_hash_lock); 412 list_splice_init(&rxnet->peer_keepalive_new, &collector); 413 414 stop = cursor + ARRAY_SIZE(rxnet->peer_keepalive); 415 while (base <= now && (s8)(cursor - stop) < 0) { 416 list_splice_tail_init(&rxnet->peer_keepalive[cursor & mask], 417 &collector); 418 base++; 419 cursor++; 420 } 421 422 base = now; 423 spin_unlock_bh(&rxnet->peer_hash_lock); 424 425 rxnet->peer_keepalive_base = base; 426 rxnet->peer_keepalive_cursor = cursor; 427 rxrpc_peer_keepalive_dispatch(rxnet, &collector, base, cursor); 428 ASSERT(list_empty(&collector)); 429 430 /* Schedule the timer for the next occupied timeslot. */ 431 cursor = rxnet->peer_keepalive_cursor; 432 stop = cursor + RXRPC_KEEPALIVE_TIME - 1; 433 for (; (s8)(cursor - stop) < 0; cursor++) { 434 if (!list_empty(&rxnet->peer_keepalive[cursor & mask])) 435 break; 436 base++; 437 } 438 439 now = ktime_get_seconds(); 440 delay = base - now; 441 if (delay < 1) 442 delay = 1; 443 delay *= HZ; 444 if (rxnet->live) 445 timer_reduce(&rxnet->peer_keepalive_timer, jiffies + delay); 446 447 _leave(""); 448 } 449