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 serr = SKB_EXT_ERR(skb); 133 if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) { 134 _leave("UDP empty message"); 135 kfree_skb(skb); 136 return; 137 } 138 139 rxrpc_new_skb(skb); 140 141 rcu_read_lock(); 142 peer = rxrpc_lookup_peer_icmp_rcu(local, skb); 143 if (peer && !rxrpc_get_peer_maybe(peer)) 144 peer = NULL; 145 if (!peer) { 146 rcu_read_unlock(); 147 rxrpc_free_skb(skb); 148 _leave(" [no peer]"); 149 return; 150 } 151 152 if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP && 153 serr->ee.ee_type == ICMP_DEST_UNREACH && 154 serr->ee.ee_code == ICMP_FRAG_NEEDED)) { 155 rxrpc_adjust_mtu(peer, serr); 156 rcu_read_unlock(); 157 rxrpc_free_skb(skb); 158 rxrpc_put_peer(peer); 159 _leave(" [MTU update]"); 160 return; 161 } 162 163 rxrpc_store_error(peer, serr); 164 rcu_read_unlock(); 165 rxrpc_free_skb(skb); 166 167 /* The ref we obtained is passed off to the work item */ 168 rxrpc_queue_work(&peer->error_distributor); 169 _leave(""); 170 } 171 172 /* 173 * Map an error report to error codes on the peer record. 174 */ 175 static void rxrpc_store_error(struct rxrpc_peer *peer, 176 struct sock_exterr_skb *serr) 177 { 178 struct sock_extended_err *ee; 179 int err; 180 181 _enter(""); 182 183 ee = &serr->ee; 184 185 _net("Rx Error o=%d t=%d c=%d e=%d", 186 ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno); 187 188 err = ee->ee_errno; 189 190 switch (ee->ee_origin) { 191 case SO_EE_ORIGIN_ICMP: 192 switch (ee->ee_type) { 193 case ICMP_DEST_UNREACH: 194 switch (ee->ee_code) { 195 case ICMP_NET_UNREACH: 196 _net("Rx Received ICMP Network Unreachable"); 197 break; 198 case ICMP_HOST_UNREACH: 199 _net("Rx Received ICMP Host Unreachable"); 200 break; 201 case ICMP_PORT_UNREACH: 202 _net("Rx Received ICMP Port Unreachable"); 203 break; 204 case ICMP_NET_UNKNOWN: 205 _net("Rx Received ICMP Unknown Network"); 206 break; 207 case ICMP_HOST_UNKNOWN: 208 _net("Rx Received ICMP Unknown Host"); 209 break; 210 default: 211 _net("Rx Received ICMP DestUnreach code=%u", 212 ee->ee_code); 213 break; 214 } 215 break; 216 217 case ICMP_TIME_EXCEEDED: 218 _net("Rx Received ICMP TTL Exceeded"); 219 break; 220 221 default: 222 _proto("Rx Received ICMP error { type=%u code=%u }", 223 ee->ee_type, ee->ee_code); 224 break; 225 } 226 break; 227 228 case SO_EE_ORIGIN_NONE: 229 case SO_EE_ORIGIN_LOCAL: 230 _proto("Rx Received local error { error=%d }", err); 231 err += RXRPC_LOCAL_ERROR_OFFSET; 232 break; 233 234 case SO_EE_ORIGIN_ICMP6: 235 default: 236 _proto("Rx Received error report { orig=%u }", ee->ee_origin); 237 break; 238 } 239 240 peer->error_report = err; 241 } 242 243 /* 244 * Distribute an error that occurred on a peer 245 */ 246 void rxrpc_peer_error_distributor(struct work_struct *work) 247 { 248 struct rxrpc_peer *peer = 249 container_of(work, struct rxrpc_peer, error_distributor); 250 struct rxrpc_call *call; 251 int error_report; 252 253 _enter(""); 254 255 error_report = READ_ONCE(peer->error_report); 256 257 _debug("ISSUE ERROR %d", error_report); 258 259 spin_lock_bh(&peer->lock); 260 261 while (!hlist_empty(&peer->error_targets)) { 262 call = hlist_entry(peer->error_targets.first, 263 struct rxrpc_call, error_link); 264 hlist_del_init(&call->error_link); 265 266 write_lock(&call->state_lock); 267 if (call->state != RXRPC_CALL_COMPLETE && 268 call->state < RXRPC_CALL_NETWORK_ERROR) { 269 call->error_report = error_report; 270 call->state = RXRPC_CALL_NETWORK_ERROR; 271 set_bit(RXRPC_CALL_EV_RCVD_ERROR, &call->events); 272 rxrpc_queue_call(call); 273 } 274 write_unlock(&call->state_lock); 275 } 276 277 spin_unlock_bh(&peer->lock); 278 279 rxrpc_put_peer(peer); 280 _leave(""); 281 } 282