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 default: 70 BUG(); 71 } 72 73 return rxrpc_lookup_peer_rcu(local, &srx); 74 } 75 76 /* 77 * Handle an MTU/fragmentation problem. 78 */ 79 static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *serr) 80 { 81 u32 mtu = serr->ee.ee_info; 82 83 _net("Rx ICMP Fragmentation Needed (%d)", mtu); 84 85 /* wind down the local interface MTU */ 86 if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) { 87 peer->if_mtu = mtu; 88 _net("I/F MTU %u", mtu); 89 } 90 91 if (mtu == 0) { 92 /* they didn't give us a size, estimate one */ 93 mtu = peer->if_mtu; 94 if (mtu > 1500) { 95 mtu >>= 1; 96 if (mtu < 1500) 97 mtu = 1500; 98 } else { 99 mtu -= 100; 100 if (mtu < peer->hdrsize) 101 mtu = peer->hdrsize + 4; 102 } 103 } 104 105 if (mtu < peer->mtu) { 106 spin_lock_bh(&peer->lock); 107 peer->mtu = mtu; 108 peer->maxdata = peer->mtu - peer->hdrsize; 109 spin_unlock_bh(&peer->lock); 110 _net("Net MTU %u (maxdata %u)", 111 peer->mtu, peer->maxdata); 112 } 113 } 114 115 /* 116 * Handle an error received on the local endpoint. 117 */ 118 void rxrpc_error_report(struct sock *sk) 119 { 120 struct sock_exterr_skb *serr; 121 struct rxrpc_local *local = sk->sk_user_data; 122 struct rxrpc_peer *peer; 123 struct sk_buff *skb; 124 125 _enter("%p{%d}", sk, local->debug_id); 126 127 skb = sock_dequeue_err_skb(sk); 128 if (!skb) { 129 _leave("UDP socket errqueue empty"); 130 return; 131 } 132 rxrpc_new_skb(skb); 133 serr = SKB_EXT_ERR(skb); 134 if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) { 135 _leave("UDP empty message"); 136 rxrpc_free_skb(skb); 137 return; 138 } 139 140 rcu_read_lock(); 141 peer = rxrpc_lookup_peer_icmp_rcu(local, skb); 142 if (peer && !rxrpc_get_peer_maybe(peer)) 143 peer = NULL; 144 if (!peer) { 145 rcu_read_unlock(); 146 rxrpc_free_skb(skb); 147 _leave(" [no peer]"); 148 return; 149 } 150 151 if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP && 152 serr->ee.ee_type == ICMP_DEST_UNREACH && 153 serr->ee.ee_code == ICMP_FRAG_NEEDED)) { 154 rxrpc_adjust_mtu(peer, serr); 155 rcu_read_unlock(); 156 rxrpc_free_skb(skb); 157 rxrpc_put_peer(peer); 158 _leave(" [MTU update]"); 159 return; 160 } 161 162 rxrpc_store_error(peer, serr); 163 rcu_read_unlock(); 164 rxrpc_free_skb(skb); 165 166 /* The ref we obtained is passed off to the work item */ 167 rxrpc_queue_work(&peer->error_distributor); 168 _leave(""); 169 } 170 171 /* 172 * Map an error report to error codes on the peer record. 173 */ 174 static void rxrpc_store_error(struct rxrpc_peer *peer, 175 struct sock_exterr_skb *serr) 176 { 177 struct sock_extended_err *ee; 178 int err; 179 180 _enter(""); 181 182 ee = &serr->ee; 183 184 _net("Rx Error o=%d t=%d c=%d e=%d", 185 ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno); 186 187 err = ee->ee_errno; 188 189 switch (ee->ee_origin) { 190 case SO_EE_ORIGIN_ICMP: 191 switch (ee->ee_type) { 192 case ICMP_DEST_UNREACH: 193 switch (ee->ee_code) { 194 case ICMP_NET_UNREACH: 195 _net("Rx Received ICMP Network Unreachable"); 196 break; 197 case ICMP_HOST_UNREACH: 198 _net("Rx Received ICMP Host Unreachable"); 199 break; 200 case ICMP_PORT_UNREACH: 201 _net("Rx Received ICMP Port Unreachable"); 202 break; 203 case ICMP_NET_UNKNOWN: 204 _net("Rx Received ICMP Unknown Network"); 205 break; 206 case ICMP_HOST_UNKNOWN: 207 _net("Rx Received ICMP Unknown Host"); 208 break; 209 default: 210 _net("Rx Received ICMP DestUnreach code=%u", 211 ee->ee_code); 212 break; 213 } 214 break; 215 216 case ICMP_TIME_EXCEEDED: 217 _net("Rx Received ICMP TTL Exceeded"); 218 break; 219 220 default: 221 _proto("Rx Received ICMP error { type=%u code=%u }", 222 ee->ee_type, ee->ee_code); 223 break; 224 } 225 break; 226 227 case SO_EE_ORIGIN_NONE: 228 case SO_EE_ORIGIN_LOCAL: 229 _proto("Rx Received local error { error=%d }", err); 230 err += RXRPC_LOCAL_ERROR_OFFSET; 231 break; 232 233 case SO_EE_ORIGIN_ICMP6: 234 default: 235 _proto("Rx Received error report { orig=%u }", ee->ee_origin); 236 break; 237 } 238 239 peer->error_report = err; 240 } 241 242 /* 243 * Distribute an error that occurred on a peer 244 */ 245 void rxrpc_peer_error_distributor(struct work_struct *work) 246 { 247 struct rxrpc_peer *peer = 248 container_of(work, struct rxrpc_peer, error_distributor); 249 struct rxrpc_call *call; 250 enum rxrpc_call_completion compl; 251 int error; 252 253 _enter(""); 254 255 error = READ_ONCE(peer->error_report); 256 if (error < RXRPC_LOCAL_ERROR_OFFSET) { 257 compl = RXRPC_CALL_NETWORK_ERROR; 258 } else { 259 compl = RXRPC_CALL_LOCAL_ERROR; 260 error -= RXRPC_LOCAL_ERROR_OFFSET; 261 } 262 263 _debug("ISSUE ERROR %s %d", rxrpc_call_completions[compl], error); 264 265 spin_lock_bh(&peer->lock); 266 267 while (!hlist_empty(&peer->error_targets)) { 268 call = hlist_entry(peer->error_targets.first, 269 struct rxrpc_call, error_link); 270 hlist_del_init(&call->error_link); 271 rxrpc_see_call(call); 272 273 if (rxrpc_set_call_completion(call, compl, 0, error)) 274 rxrpc_notify_socket(call); 275 } 276 277 spin_unlock_bh(&peer->lock); 278 279 rxrpc_put_peer(peer); 280 _leave(""); 281 } 282