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 */
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 "NIPQUAD_FMT":%hu",
53 NIPQUAD(addr), ntohs(port));
54 _debug("Msg l:%d d:%d", skb->len, skb->data_len);
55
56 peer = rxrpc_find_peer(local, addr, port);
57 if (IS_ERR(peer)) {
58 rxrpc_free_skb(skb);
59 _leave(" [no peer]");
60 return;
61 }
62
63 trans = rxrpc_find_transport(local, peer);
64 if (!trans) {
65 rxrpc_put_peer(peer);
66 rxrpc_free_skb(skb);
67 _leave(" [no trans]");
68 return;
69 }
70
71 if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
72 serr->ee.ee_type == ICMP_DEST_UNREACH &&
73 serr->ee.ee_code == ICMP_FRAG_NEEDED
74 ) {
75 u32 mtu = serr->ee.ee_info;
76
77 _net("Rx Received ICMP Fragmentation Needed (%d)", mtu);
78
79 /* wind down the local interface MTU */
80 if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
81 peer->if_mtu = mtu;
82 _net("I/F MTU %u", mtu);
83 }
84
85 /* ip_rt_frag_needed() may have eaten the info */
86 if (mtu == 0)
87 mtu = ntohs(icmp_hdr(skb)->un.frag.mtu);
88
89 if (mtu == 0) {
90 /* they didn't give us a size, estimate one */
91 if (mtu > 1500) {
92 mtu >>= 1;
93 if (mtu < 1500)
94 mtu = 1500;
95 } else {
96 mtu -= 100;
97 if (mtu < peer->hdrsize)
98 mtu = peer->hdrsize + 4;
99 }
100 }
101
102 if (mtu < peer->mtu) {
103 spin_lock_bh(&peer->lock);
104 peer->mtu = mtu;
105 peer->maxdata = peer->mtu - peer->hdrsize;
106 spin_unlock_bh(&peer->lock);
107 _net("Net MTU %u (maxdata %u)",
108 peer->mtu, peer->maxdata);
109 }
110 }
111
112 rxrpc_put_peer(peer);
113
114 /* pass the transport ref to error_handler to release */
115 skb_queue_tail(&trans->error_queue, skb);
116 rxrpc_queue_work(&trans->error_handler);
117
118 /* reset and regenerate socket error */
119 spin_lock_bh(&sk->sk_error_queue.lock);
120 sk->sk_err = 0;
121 skb = skb_peek(&sk->sk_error_queue);
122 if (skb) {
123 sk->sk_err = SKB_EXT_ERR(skb)->ee.ee_errno;
124 spin_unlock_bh(&sk->sk_error_queue.lock);
125 sk->sk_error_report(sk);
126 } else {
127 spin_unlock_bh(&sk->sk_error_queue.lock);
128 }
129
130 _leave("");
131 }
132
133 /*
134 * deal with UDP error messages
135 */
136 void rxrpc_UDP_error_handler(struct work_struct *work)
137 {
138 struct sock_extended_err *ee;
139 struct sock_exterr_skb *serr;
140 struct rxrpc_transport *trans =
141 container_of(work, struct rxrpc_transport, error_handler);
142 struct sk_buff *skb;
143 int local, err;
144
145 _enter("");
146
147 skb = skb_dequeue(&trans->error_queue);
148 if (!skb)
149 return;
150
151 serr = SKB_EXT_ERR(skb);
152 ee = &serr->ee;
153
154 _net("Rx Error o=%d t=%d c=%d e=%d",
155 ee->ee_origin, ee->ee_type, ee->ee_code, ee->ee_errno);
156
157 err = ee->ee_errno;
158
159 switch (ee->ee_origin) {
160 case SO_EE_ORIGIN_ICMP:
161 local = 0;
162 switch (ee->ee_type) {
163 case ICMP_DEST_UNREACH:
164 switch (ee->ee_code) {
165 case ICMP_NET_UNREACH:
166 _net("Rx Received ICMP Network Unreachable");
167 err = ENETUNREACH;
168 break;
169 case ICMP_HOST_UNREACH:
170 _net("Rx Received ICMP Host Unreachable");
171 err = EHOSTUNREACH;
172 break;
173 case ICMP_PORT_UNREACH:
174 _net("Rx Received ICMP Port Unreachable");
175 err = ECONNREFUSED;
176 break;
177 case ICMP_FRAG_NEEDED:
178 _net("Rx Received ICMP Fragmentation Needed (%d)",
179 ee->ee_info);
180 err = 0; /* dealt with elsewhere */
181 break;
182 case ICMP_NET_UNKNOWN:
183 _net("Rx Received ICMP Unknown Network");
184 err = ENETUNREACH;
185 break;
186 case ICMP_HOST_UNKNOWN:
187 _net("Rx Received ICMP Unknown Host");
188 err = EHOSTUNREACH;
189 break;
190 default:
191 _net("Rx Received ICMP DestUnreach code=%u",
192 ee->ee_code);
193 break;
194 }
195 break;
196
197 case ICMP_TIME_EXCEEDED:
198 _net("Rx Received ICMP TTL Exceeded");
199 break;
200
201 default:
202 _proto("Rx Received ICMP error { type=%u code=%u }",
203 ee->ee_type, ee->ee_code);
204 break;
205 }
206 break;
207
208 case SO_EE_ORIGIN_LOCAL:
209 _proto("Rx Received local error { error=%d }",
210 ee->ee_errno);
211 local = 1;
212 break;
213
214 case SO_EE_ORIGIN_NONE:
215 case SO_EE_ORIGIN_ICMP6:
216 default:
217 _proto("Rx Received error report { orig=%u }",
218 ee->ee_origin);
219 local = 0;
220 break;
221 }
222
223 /* terminate all the affected calls if there's an unrecoverable
224 * error */
225 if (err) {
226 struct rxrpc_call *call, *_n;
227
228 _debug("ISSUE ERROR %d", err);
229
230 spin_lock_bh(&trans->peer->lock);
231 trans->peer->net_error = err;
232
233 list_for_each_entry_safe(call, _n, &trans->peer->error_targets,
234 error_link) {
235 write_lock(&call->state_lock);
236 if (call->state != RXRPC_CALL_COMPLETE &&
237 call->state < RXRPC_CALL_NETWORK_ERROR) {
238 call->state = RXRPC_CALL_NETWORK_ERROR;
239 set_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
240 rxrpc_queue_call(call);
241 }
242 write_unlock(&call->state_lock);
243 list_del_init(&call->error_link);
244 }
245
246 spin_unlock_bh(&trans->peer->lock);
247 }
248
249 if (!skb_queue_empty(&trans->error_queue))
250 rxrpc_queue_work(&trans->error_handler);
251
252 rxrpc_free_skb(skb);
253 rxrpc_put_transport(trans);
254 _leave("");
255 }
256
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