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 { 33 struct sock_exterr_skb *serr = SKB_EXT_ERR(skb); 34 struct sockaddr_rxrpc srx; 35 36 _enter(""); 37 38 memset(&srx, 0, sizeof(srx)); 39 srx.transport_type = local->srx.transport_type; 40 srx.transport.family = local->srx.transport.family; 41 42 /* Can we see an ICMP4 packet on an ICMP6 listening socket? and vice 43 * versa? 44 */ 45 switch (srx.transport.family) { 46 case AF_INET: 47 srx.transport.sin.sin_port = serr->port; 48 srx.transport_len = sizeof(struct sockaddr_in); 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 srx.transport_len = sizeof(struct sockaddr_in6); 73 switch (serr->ee.ee_origin) { 74 case SO_EE_ORIGIN_ICMP6: 75 _net("Rx ICMP6"); 76 memcpy(&srx.transport.sin6.sin6_addr, 77 skb_network_header(skb) + serr->addr_offset, 78 sizeof(struct in6_addr)); 79 break; 80 case SO_EE_ORIGIN_ICMP: 81 _net("Rx ICMP on v6 sock"); 82 memcpy(srx.transport.sin6.sin6_addr.s6_addr + 12, 83 skb_network_header(skb) + serr->addr_offset, 84 sizeof(struct in_addr)); 85 break; 86 default: 87 memcpy(&srx.transport.sin6.sin6_addr, 88 &ipv6_hdr(skb)->saddr, 89 sizeof(struct in6_addr)); 90 break; 91 } 92 break; 93 #endif 94 95 default: 96 BUG(); 97 } 98 99 return rxrpc_lookup_peer_rcu(local, &srx); 100 } 101 102 /* 103 * Handle an MTU/fragmentation problem. 104 */ 105 static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *serr) 106 { 107 u32 mtu = serr->ee.ee_info; 108 109 _net("Rx ICMP Fragmentation Needed (%d)", mtu); 110 111 /* wind down the local interface MTU */ 112 if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) { 113 peer->if_mtu = mtu; 114 _net("I/F MTU %u", mtu); 115 } 116 117 if (mtu == 0) { 118 /* they didn't give us a size, estimate one */ 119 mtu = peer->if_mtu; 120 if (mtu > 1500) { 121 mtu >>= 1; 122 if (mtu < 1500) 123 mtu = 1500; 124 } else { 125 mtu -= 100; 126 if (mtu < peer->hdrsize) 127 mtu = peer->hdrsize + 4; 128 } 129 } 130 131 if (mtu < peer->mtu) { 132 spin_lock_bh(&peer->lock); 133 peer->mtu = mtu; 134 peer->maxdata = peer->mtu - peer->hdrsize; 135 spin_unlock_bh(&peer->lock); 136 _net("Net MTU %u (maxdata %u)", 137 peer->mtu, peer->maxdata); 138 } 139 } 140 141 /* 142 * Handle an error received on the local endpoint. 143 */ 144 void rxrpc_error_report(struct sock *sk) 145 { 146 struct sock_exterr_skb *serr; 147 struct rxrpc_local *local = sk->sk_user_data; 148 struct rxrpc_peer *peer; 149 struct sk_buff *skb; 150 151 _enter("%p{%d}", sk, local->debug_id); 152 153 skb = sock_dequeue_err_skb(sk); 154 if (!skb) { 155 _leave("UDP socket errqueue empty"); 156 return; 157 } 158 rxrpc_new_skb(skb, rxrpc_skb_rx_received); 159 serr = SKB_EXT_ERR(skb); 160 if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) { 161 _leave("UDP empty message"); 162 rxrpc_free_skb(skb, rxrpc_skb_rx_freed); 163 return; 164 } 165 166 rcu_read_lock(); 167 peer = rxrpc_lookup_peer_icmp_rcu(local, skb); 168 if (peer && !rxrpc_get_peer_maybe(peer)) 169 peer = NULL; 170 if (!peer) { 171 rcu_read_unlock(); 172 rxrpc_free_skb(skb, rxrpc_skb_rx_freed); 173 _leave(" [no peer]"); 174 return; 175 } 176 177 if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP && 178 serr->ee.ee_type == ICMP_DEST_UNREACH && 179 serr->ee.ee_code == ICMP_FRAG_NEEDED)) { 180 rxrpc_adjust_mtu(peer, serr); 181 rcu_read_unlock(); 182 rxrpc_free_skb(skb, rxrpc_skb_rx_freed); 183 rxrpc_put_peer(peer); 184 _leave(" [MTU update]"); 185 return; 186 } 187 188 rxrpc_store_error(peer, serr); 189 rcu_read_unlock(); 190 rxrpc_free_skb(skb, rxrpc_skb_rx_freed); 191 192 /* The ref we obtained is passed off to the work item */ 193 rxrpc_queue_work(&peer->error_distributor); 194 _leave(""); 195 } 196 197 /* 198 * Map an error report to error codes on the peer record. 199 */ 200 static void rxrpc_store_error(struct rxrpc_peer *peer, 201 struct sock_exterr_skb *serr) 202 { 203 struct sock_extended_err *ee; 204 int err; 205 206 _enter(""); 207 208 ee = &serr->ee; 209 210 _net("Rx Error o=%d t=%d c=%d e=%d", 211 ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno); 212 213 err = ee->ee_errno; 214 215 switch (ee->ee_origin) { 216 case SO_EE_ORIGIN_ICMP: 217 switch (ee->ee_type) { 218 case ICMP_DEST_UNREACH: 219 switch (ee->ee_code) { 220 case ICMP_NET_UNREACH: 221 _net("Rx Received ICMP Network Unreachable"); 222 break; 223 case ICMP_HOST_UNREACH: 224 _net("Rx Received ICMP Host Unreachable"); 225 break; 226 case ICMP_PORT_UNREACH: 227 _net("Rx Received ICMP Port Unreachable"); 228 break; 229 case ICMP_NET_UNKNOWN: 230 _net("Rx Received ICMP Unknown Network"); 231 break; 232 case ICMP_HOST_UNKNOWN: 233 _net("Rx Received ICMP Unknown Host"); 234 break; 235 default: 236 _net("Rx Received ICMP DestUnreach code=%u", 237 ee->ee_code); 238 break; 239 } 240 break; 241 242 case ICMP_TIME_EXCEEDED: 243 _net("Rx Received ICMP TTL Exceeded"); 244 break; 245 246 default: 247 _proto("Rx Received ICMP error { type=%u code=%u }", 248 ee->ee_type, ee->ee_code); 249 break; 250 } 251 break; 252 253 case SO_EE_ORIGIN_NONE: 254 case SO_EE_ORIGIN_LOCAL: 255 _proto("Rx Received local error { error=%d }", err); 256 err += RXRPC_LOCAL_ERROR_OFFSET; 257 break; 258 259 case SO_EE_ORIGIN_ICMP6: 260 default: 261 _proto("Rx Received error report { orig=%u }", ee->ee_origin); 262 break; 263 } 264 265 peer->error_report = err; 266 } 267 268 /* 269 * Distribute an error that occurred on a peer 270 */ 271 void rxrpc_peer_error_distributor(struct work_struct *work) 272 { 273 struct rxrpc_peer *peer = 274 container_of(work, struct rxrpc_peer, error_distributor); 275 struct rxrpc_call *call; 276 enum rxrpc_call_completion compl; 277 int error; 278 279 _enter(""); 280 281 error = READ_ONCE(peer->error_report); 282 if (error < RXRPC_LOCAL_ERROR_OFFSET) { 283 compl = RXRPC_CALL_NETWORK_ERROR; 284 } else { 285 compl = RXRPC_CALL_LOCAL_ERROR; 286 error -= RXRPC_LOCAL_ERROR_OFFSET; 287 } 288 289 _debug("ISSUE ERROR %s %d", rxrpc_call_completions[compl], error); 290 291 spin_lock_bh(&peer->lock); 292 293 while (!hlist_empty(&peer->error_targets)) { 294 call = hlist_entry(peer->error_targets.first, 295 struct rxrpc_call, error_link); 296 hlist_del_init(&call->error_link); 297 rxrpc_see_call(call); 298 299 if (rxrpc_set_call_completion(call, compl, 0, -error)) 300 rxrpc_notify_socket(call); 301 } 302 303 spin_unlock_bh(&peer->lock); 304 305 rxrpc_put_peer(peer); 306 _leave(""); 307 } 308 309 /* 310 * Add RTT information to cache. This is called in softirq mode and has 311 * exclusive access to the peer RTT data. 312 */ 313 void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why, 314 rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial, 315 ktime_t send_time, ktime_t resp_time) 316 { 317 struct rxrpc_peer *peer = call->peer; 318 s64 rtt; 319 u64 sum = peer->rtt_sum, avg; 320 u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage; 321 322 rtt = ktime_to_ns(ktime_sub(resp_time, send_time)); 323 if (rtt < 0) 324 return; 325 326 /* Replace the oldest datum in the RTT buffer */ 327 sum -= peer->rtt_cache[cursor]; 328 sum += rtt; 329 peer->rtt_cache[cursor] = rtt; 330 peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1); 331 peer->rtt_sum = sum; 332 if (usage < RXRPC_RTT_CACHE_SIZE) { 333 usage++; 334 peer->rtt_usage = usage; 335 } 336 337 /* Now recalculate the average */ 338 if (usage == RXRPC_RTT_CACHE_SIZE) { 339 avg = sum / RXRPC_RTT_CACHE_SIZE; 340 } else { 341 avg = sum; 342 do_div(avg, usage); 343 } 344 345 peer->rtt = avg; 346 trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt, 347 usage, avg); 348 } 349