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