1 /* Error message handling (ICMP)
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 /*
26 * handle an error received on the local endpoint
27 */
rxrpc_UDP_error_report(struct sock * sk)28 void rxrpc_UDP_error_report(struct sock *sk)
29 {
30 struct sock_exterr_skb *serr;
31 struct rxrpc_transport *trans;
32 struct rxrpc_local *local = sk->sk_user_data;
33 struct rxrpc_peer *peer;
34 struct sk_buff *skb;
35 __be32 addr;
36 __be16 port;
37
38 _enter("%p{%d}", sk, local->debug_id);
39
40 skb = skb_dequeue(&sk->sk_error_queue);
41 if (!skb) {
42 _leave("UDP socket errqueue empty");
43 return;
44 }
45
46 rxrpc_new_skb(skb);
47
48 serr = SKB_EXT_ERR(skb);
49 addr = *(__be32 *)(skb_network_header(skb) + serr->addr_offset);
50 port = serr->port;
51
52 _net("Rx UDP Error from %pI4:%hu", &addr, ntohs(port));
53 _debug("Msg l:%d d:%d", skb->len, skb->data_len);
54
55 peer = rxrpc_find_peer(local, addr, port);
56 if (IS_ERR(peer)) {
57 rxrpc_free_skb(skb);
58 _leave(" [no peer]");
59 return;
60 }
61
62 trans = rxrpc_find_transport(local, peer);
63 if (!trans) {
64 rxrpc_put_peer(peer);
65 rxrpc_free_skb(skb);
66 _leave(" [no trans]");
67 return;
68 }
69
70 if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
71 serr->ee.ee_type == ICMP_DEST_UNREACH &&
72 serr->ee.ee_code == ICMP_FRAG_NEEDED
73 ) {
74 u32 mtu = serr->ee.ee_info;
75
76 _net("Rx Received ICMP Fragmentation Needed (%d)", mtu);
77
78 /* wind down the local interface MTU */
79 if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
80 peer->if_mtu = mtu;
81 _net("I/F MTU %u", mtu);
82 }
83
84 if (mtu == 0) {
85 /* they didn't give us a size, estimate one */
86 if (mtu > 1500) {
87 mtu >>= 1;
88 if (mtu < 1500)
89 mtu = 1500;
90 } else {
91 mtu -= 100;
92 if (mtu < peer->hdrsize)
93 mtu = peer->hdrsize + 4;
94 }
95 }
96
97 if (mtu < peer->mtu) {
98 spin_lock_bh(&peer->lock);
99 peer->mtu = mtu;
100 peer->maxdata = peer->mtu - peer->hdrsize;
101 spin_unlock_bh(&peer->lock);
102 _net("Net MTU %u (maxdata %u)",
103 peer->mtu, peer->maxdata);
104 }
105 }
106
107 rxrpc_put_peer(peer);
108
109 /* pass the transport ref to error_handler to release */
110 skb_queue_tail(&trans->error_queue, skb);
111 rxrpc_queue_work(&trans->error_handler);
112
113 /* reset and regenerate socket error */
114 spin_lock_bh(&sk->sk_error_queue.lock);
115 sk->sk_err = 0;
116 skb = skb_peek(&sk->sk_error_queue);
117 if (skb) {
118 sk->sk_err = SKB_EXT_ERR(skb)->ee.ee_errno;
119 spin_unlock_bh(&sk->sk_error_queue.lock);
120 sk->sk_error_report(sk);
121 } else {
122 spin_unlock_bh(&sk->sk_error_queue.lock);
123 }
124
125 _leave("");
126 }
127
128 /*
129 * deal with UDP error messages
130 */
rxrpc_UDP_error_handler(struct work_struct * work)131 void rxrpc_UDP_error_handler(struct work_struct *work)
132 {
133 struct sock_extended_err *ee;
134 struct sock_exterr_skb *serr;
135 struct rxrpc_transport *trans =
136 container_of(work, struct rxrpc_transport, error_handler);
137 struct sk_buff *skb;
138 int err;
139
140 _enter("");
141
142 skb = skb_dequeue(&trans->error_queue);
143 if (!skb)
144 return;
145
146 serr = SKB_EXT_ERR(skb);
147 ee = &serr->ee;
148
149 _net("Rx Error o=%d t=%d c=%d e=%d",
150 ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
151
152 err = ee->ee_errno;
153
154 switch (ee->ee_origin) {
155 case SO_EE_ORIGIN_ICMP:
156 switch (ee->ee_type) {
157 case ICMP_DEST_UNREACH:
158 switch (ee->ee_code) {
159 case ICMP_NET_UNREACH:
160 _net("Rx Received ICMP Network Unreachable");
161 err = ENETUNREACH;
162 break;
163 case ICMP_HOST_UNREACH:
164 _net("Rx Received ICMP Host Unreachable");
165 err = EHOSTUNREACH;
166 break;
167 case ICMP_PORT_UNREACH:
168 _net("Rx Received ICMP Port Unreachable");
169 err = ECONNREFUSED;
170 break;
171 case ICMP_FRAG_NEEDED:
172 _net("Rx Received ICMP Fragmentation Needed (%d)",
173 ee->ee_info);
174 err = 0; /* dealt with elsewhere */
175 break;
176 case ICMP_NET_UNKNOWN:
177 _net("Rx Received ICMP Unknown Network");
178 err = ENETUNREACH;
179 break;
180 case ICMP_HOST_UNKNOWN:
181 _net("Rx Received ICMP Unknown Host");
182 err = EHOSTUNREACH;
183 break;
184 default:
185 _net("Rx Received ICMP DestUnreach code=%u",
186 ee->ee_code);
187 break;
188 }
189 break;
190
191 case ICMP_TIME_EXCEEDED:
192 _net("Rx Received ICMP TTL Exceeded");
193 break;
194
195 default:
196 _proto("Rx Received ICMP error { type=%u code=%u }",
197 ee->ee_type, ee->ee_code);
198 break;
199 }
200 break;
201
202 case SO_EE_ORIGIN_LOCAL:
203 _proto("Rx Received local error { error=%d }",
204 ee->ee_errno);
205 break;
206
207 case SO_EE_ORIGIN_NONE:
208 case SO_EE_ORIGIN_ICMP6:
209 default:
210 _proto("Rx Received error report { orig=%u }",
211 ee->ee_origin);
212 break;
213 }
214
215 /* terminate all the affected calls if there's an unrecoverable
216 * error */
217 if (err) {
218 struct rxrpc_call *call, *_n;
219
220 _debug("ISSUE ERROR %d", err);
221
222 spin_lock_bh(&trans->peer->lock);
223 trans->peer->net_error = err;
224
225 list_for_each_entry_safe(call, _n, &trans->peer->error_targets,
226 error_link) {
227 write_lock(&call->state_lock);
228 if (call->state != RXRPC_CALL_COMPLETE &&
229 call->state < RXRPC_CALL_NETWORK_ERROR) {
230 call->state = RXRPC_CALL_NETWORK_ERROR;
231 set_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
232 rxrpc_queue_call(call);
233 }
234 write_unlock(&call->state_lock);
235 list_del_init(&call->error_link);
236 }
237
238 spin_unlock_bh(&trans->peer->lock);
239 }
240
241 if (!skb_queue_empty(&trans->error_queue))
242 rxrpc_queue_work(&trans->error_handler);
243
244 rxrpc_free_skb(skb);
245 rxrpc_put_transport(trans);
246 _leave("");
247 }
248