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; 151 struct rxrpc_peer *peer; 152 struct sk_buff *skb; 153 154 rcu_read_lock(); 155 local = rcu_dereference_sk_user_data(sk); 156 if (unlikely(!local)) { 157 rcu_read_unlock(); 158 return; 159 } 160 _enter("%p{%d}", sk, local->debug_id); 161 162 /* Clear the outstanding error value on the socket so that it doesn't 163 * cause kernel_sendmsg() to return it later. 164 */ 165 sock_error(sk); 166 167 skb = sock_dequeue_err_skb(sk); 168 if (!skb) { 169 rcu_read_unlock(); 170 _leave("UDP socket errqueue empty"); 171 return; 172 } 173 rxrpc_new_skb(skb, rxrpc_skb_received); 174 serr = SKB_EXT_ERR(skb); 175 if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) { 176 _leave("UDP empty message"); 177 rcu_read_unlock(); 178 rxrpc_free_skb(skb, rxrpc_skb_freed); 179 return; 180 } 181 182 peer = rxrpc_lookup_peer_icmp_rcu(local, skb, &srx); 183 if (peer && !rxrpc_get_peer_maybe(peer)) 184 peer = NULL; 185 if (!peer) { 186 rcu_read_unlock(); 187 rxrpc_free_skb(skb, rxrpc_skb_freed); 188 _leave(" [no peer]"); 189 return; 190 } 191 192 trace_rxrpc_rx_icmp(peer, &serr->ee, &srx); 193 194 if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP && 195 serr->ee.ee_type == ICMP_DEST_UNREACH && 196 serr->ee.ee_code == ICMP_FRAG_NEEDED)) { 197 rxrpc_adjust_mtu(peer, serr); 198 rcu_read_unlock(); 199 rxrpc_free_skb(skb, rxrpc_skb_freed); 200 rxrpc_put_peer(peer); 201 _leave(" [MTU update]"); 202 return; 203 } 204 205 rxrpc_store_error(peer, serr); 206 rcu_read_unlock(); 207 rxrpc_free_skb(skb, rxrpc_skb_freed); 208 rxrpc_put_peer(peer); 209 210 _leave(""); 211 } 212 213 /* 214 * Map an error report to error codes on the peer record. 215 */ 216 static void rxrpc_store_error(struct rxrpc_peer *peer, 217 struct sock_exterr_skb *serr) 218 { 219 enum rxrpc_call_completion compl = RXRPC_CALL_NETWORK_ERROR; 220 struct sock_extended_err *ee; 221 int err; 222 223 _enter(""); 224 225 ee = &serr->ee; 226 227 err = ee->ee_errno; 228 229 switch (ee->ee_origin) { 230 case SO_EE_ORIGIN_ICMP: 231 switch (ee->ee_type) { 232 case ICMP_DEST_UNREACH: 233 switch (ee->ee_code) { 234 case ICMP_NET_UNREACH: 235 _net("Rx Received ICMP Network Unreachable"); 236 break; 237 case ICMP_HOST_UNREACH: 238 _net("Rx Received ICMP Host Unreachable"); 239 break; 240 case ICMP_PORT_UNREACH: 241 _net("Rx Received ICMP Port Unreachable"); 242 break; 243 case ICMP_NET_UNKNOWN: 244 _net("Rx Received ICMP Unknown Network"); 245 break; 246 case ICMP_HOST_UNKNOWN: 247 _net("Rx Received ICMP Unknown Host"); 248 break; 249 default: 250 _net("Rx Received ICMP DestUnreach code=%u", 251 ee->ee_code); 252 break; 253 } 254 break; 255 256 case ICMP_TIME_EXCEEDED: 257 _net("Rx Received ICMP TTL Exceeded"); 258 break; 259 260 default: 261 _proto("Rx Received ICMP error { type=%u code=%u }", 262 ee->ee_type, ee->ee_code); 263 break; 264 } 265 break; 266 267 case SO_EE_ORIGIN_NONE: 268 case SO_EE_ORIGIN_LOCAL: 269 _proto("Rx Received local error { error=%d }", err); 270 compl = RXRPC_CALL_LOCAL_ERROR; 271 break; 272 273 case SO_EE_ORIGIN_ICMP6: 274 if (err == EACCES) 275 err = EHOSTUNREACH; 276 fallthrough; 277 default: 278 _proto("Rx Received error report { orig=%u }", ee->ee_origin); 279 break; 280 } 281 282 rxrpc_distribute_error(peer, err, compl); 283 } 284 285 /* 286 * Distribute an error that occurred on a peer. 287 */ 288 static void rxrpc_distribute_error(struct rxrpc_peer *peer, int error, 289 enum rxrpc_call_completion compl) 290 { 291 struct rxrpc_call *call; 292 293 hlist_for_each_entry_rcu(call, &peer->error_targets, error_link) { 294 rxrpc_see_call(call); 295 rxrpc_set_call_completion(call, compl, 0, -error); 296 } 297 } 298 299 /* 300 * Perform keep-alive pings. 301 */ 302 static void rxrpc_peer_keepalive_dispatch(struct rxrpc_net *rxnet, 303 struct list_head *collector, 304 time64_t base, 305 u8 cursor) 306 { 307 struct rxrpc_peer *peer; 308 const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1; 309 time64_t keepalive_at; 310 int slot; 311 312 spin_lock_bh(&rxnet->peer_hash_lock); 313 314 while (!list_empty(collector)) { 315 peer = list_entry(collector->next, 316 struct rxrpc_peer, keepalive_link); 317 318 list_del_init(&peer->keepalive_link); 319 if (!rxrpc_get_peer_maybe(peer)) 320 continue; 321 322 if (__rxrpc_use_local(peer->local)) { 323 spin_unlock_bh(&rxnet->peer_hash_lock); 324 325 keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME; 326 slot = keepalive_at - base; 327 _debug("%02x peer %u t=%d {%pISp}", 328 cursor, peer->debug_id, slot, &peer->srx.transport); 329 330 if (keepalive_at <= base || 331 keepalive_at > base + RXRPC_KEEPALIVE_TIME) { 332 rxrpc_send_keepalive(peer); 333 slot = RXRPC_KEEPALIVE_TIME; 334 } 335 336 /* A transmission to this peer occurred since last we 337 * examined it so put it into the appropriate future 338 * bucket. 339 */ 340 slot += cursor; 341 slot &= mask; 342 spin_lock_bh(&rxnet->peer_hash_lock); 343 list_add_tail(&peer->keepalive_link, 344 &rxnet->peer_keepalive[slot & mask]); 345 rxrpc_unuse_local(peer->local); 346 } 347 rxrpc_put_peer_locked(peer); 348 } 349 350 spin_unlock_bh(&rxnet->peer_hash_lock); 351 } 352 353 /* 354 * Perform keep-alive pings with VERSION packets to keep any NAT alive. 355 */ 356 void rxrpc_peer_keepalive_worker(struct work_struct *work) 357 { 358 struct rxrpc_net *rxnet = 359 container_of(work, struct rxrpc_net, peer_keepalive_work); 360 const u8 mask = ARRAY_SIZE(rxnet->peer_keepalive) - 1; 361 time64_t base, now, delay; 362 u8 cursor, stop; 363 LIST_HEAD(collector); 364 365 now = ktime_get_seconds(); 366 base = rxnet->peer_keepalive_base; 367 cursor = rxnet->peer_keepalive_cursor; 368 _enter("%lld,%u", base - now, cursor); 369 370 if (!rxnet->live) 371 return; 372 373 /* Remove to a temporary list all the peers that are currently lodged 374 * in expired buckets plus all new peers. 375 * 376 * Everything in the bucket at the cursor is processed this 377 * second; the bucket at cursor + 1 goes at now + 1s and so 378 * on... 379 */ 380 spin_lock_bh(&rxnet->peer_hash_lock); 381 list_splice_init(&rxnet->peer_keepalive_new, &collector); 382 383 stop = cursor + ARRAY_SIZE(rxnet->peer_keepalive); 384 while (base <= now && (s8)(cursor - stop) < 0) { 385 list_splice_tail_init(&rxnet->peer_keepalive[cursor & mask], 386 &collector); 387 base++; 388 cursor++; 389 } 390 391 base = now; 392 spin_unlock_bh(&rxnet->peer_hash_lock); 393 394 rxnet->peer_keepalive_base = base; 395 rxnet->peer_keepalive_cursor = cursor; 396 rxrpc_peer_keepalive_dispatch(rxnet, &collector, base, cursor); 397 ASSERT(list_empty(&collector)); 398 399 /* Schedule the timer for the next occupied timeslot. */ 400 cursor = rxnet->peer_keepalive_cursor; 401 stop = cursor + RXRPC_KEEPALIVE_TIME - 1; 402 for (; (s8)(cursor - stop) < 0; cursor++) { 403 if (!list_empty(&rxnet->peer_keepalive[cursor & mask])) 404 break; 405 base++; 406 } 407 408 now = ktime_get_seconds(); 409 delay = base - now; 410 if (delay < 1) 411 delay = 1; 412 delay *= HZ; 413 if (rxnet->live) 414 timer_reduce(&rxnet->peer_keepalive_timer, jiffies + delay); 415 416 _leave(""); 417 } 418