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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
25static void rxrpc_store_error(struct rxrpc_peer *, struct sock_exterr_skb *);
26
27/*
28 * Find the peer associated with an ICMP packet.
29 */
30static struct rxrpc_peer *rxrpc_lookup_peer_icmp_rcu(struct rxrpc_local *local,
31 const struct sk_buff *skb,
32 struct sockaddr_rxrpc *srx)
33{
34 struct sock_exterr_skb *serr = SKB_EXT_ERR(skb);
35
36 _enter("");
37
38 memset(srx, 0, sizeof(*srx));
39 srx->transport_type = local->srx.transport_type;
40 srx->transport_len = local->srx.transport_len;
41 srx->transport.family = local->srx.transport.family;
42
43 /* Can we see an ICMP4 packet on an ICMP6 listening socket? and vice
44 * versa?
45 */
46 switch (srx->transport.family) {
47 case AF_INET:
48 srx->transport.sin.sin_port = serr->port;
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#ifdef CONFIG_AF_RXRPC_IPV6
70 case AF_INET6:
71 srx->transport.sin6.sin6_port = serr->port;
72 switch (serr->ee.ee_origin) {
73 case SO_EE_ORIGIN_ICMP6:
74 _net("Rx ICMP6");
75 memcpy(&srx->transport.sin6.sin6_addr,
76 skb_network_header(skb) + serr->addr_offset,
77 sizeof(struct in6_addr));
78 break;
79 case SO_EE_ORIGIN_ICMP:
80 _net("Rx ICMP on v6 sock");
81 srx->transport.sin6.sin6_addr.s6_addr32[0] = 0;
82 srx->transport.sin6.sin6_addr.s6_addr32[1] = 0;
83 srx->transport.sin6.sin6_addr.s6_addr32[2] = htonl(0xffff);
84 memcpy(srx->transport.sin6.sin6_addr.s6_addr + 12,
85 skb_network_header(skb) + serr->addr_offset,
86 sizeof(struct in_addr));
87 break;
88 default:
89 memcpy(&srx->transport.sin6.sin6_addr,
90 &ipv6_hdr(skb)->saddr,
91 sizeof(struct in6_addr));
92 break;
93 }
94 break;
95#endif
96
97 default:
98 BUG();
99 }
100
101 return rxrpc_lookup_peer_rcu(local, srx);
102}
103
104/*
105 * Handle an MTU/fragmentation problem.
106 */
107static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *serr)
108{
109 u32 mtu = serr->ee.ee_info;
110
111 _net("Rx ICMP Fragmentation Needed (%d)", mtu);
112
113 /* wind down the local interface MTU */
114 if (mtu > 0 && peer->if_mtu == 65535 && mtu < peer->if_mtu) {
115 peer->if_mtu = mtu;
116 _net("I/F MTU %u", mtu);
117 }
118
119 if (mtu == 0) {
120 /* they didn't give us a size, estimate one */
121 mtu = peer->if_mtu;
122 if (mtu > 1500) {
123 mtu >>= 1;
124 if (mtu < 1500)
125 mtu = 1500;
126 } else {
127 mtu -= 100;
128 if (mtu < peer->hdrsize)
129 mtu = peer->hdrsize + 4;
130 }
131 }
132
133 if (mtu < peer->mtu) {
134 spin_lock_bh(&peer->lock);
135 peer->mtu = mtu;
136 peer->maxdata = peer->mtu - peer->hdrsize;
137 spin_unlock_bh(&peer->lock);
138 _net("Net MTU %u (maxdata %u)",
139 peer->mtu, peer->maxdata);
140 }
141}
142
143/*
144 * Handle an error received on the local endpoint.
145 */
146void rxrpc_error_report(struct sock *sk)
147{
148 struct sock_exterr_skb *serr;
149 struct sockaddr_rxrpc srx;
150 struct rxrpc_local *local = sk->sk_user_data;
151 struct rxrpc_peer *peer;
152 struct sk_buff *skb;
153
154 _enter("%p{%d}", sk, local->debug_id);
155
156 skb = sock_dequeue_err_skb(sk);
157 if (!skb) {
158 _leave("UDP socket errqueue empty");
159 return;
160 }
161 rxrpc_new_skb(skb, rxrpc_skb_rx_received);
162 serr = SKB_EXT_ERR(skb);
163 if (!skb->len && serr->ee.ee_origin == SO_EE_ORIGIN_TIMESTAMPING) {
164 _leave("UDP empty message");
165 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
166 return;
167 }
168
169 rcu_read_lock();
170 peer = rxrpc_lookup_peer_icmp_rcu(local, skb, &srx);
171 if (peer && !rxrpc_get_peer_maybe(peer))
172 peer = NULL;
173 if (!peer) {
174 rcu_read_unlock();
175 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
176 _leave(" [no peer]");
177 return;
178 }
179
180 trace_rxrpc_rx_icmp(peer, &serr->ee, &srx);
181
182 if ((serr->ee.ee_origin == SO_EE_ORIGIN_ICMP &&
183 serr->ee.ee_type == ICMP_DEST_UNREACH &&
184 serr->ee.ee_code == ICMP_FRAG_NEEDED)) {
185 rxrpc_adjust_mtu(peer, serr);
186 rcu_read_unlock();
187 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
188 rxrpc_put_peer(peer);
189 _leave(" [MTU update]");
190 return;
191 }
192
193 rxrpc_store_error(peer, serr);
194 rcu_read_unlock();
195 rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
196
197 /* The ref we obtained is passed off to the work item */
198 __rxrpc_queue_peer_error(peer);
199 _leave("");
200}
201
202/*
203 * Map an error report to error codes on the peer record.
204 */
205static void rxrpc_store_error(struct rxrpc_peer *peer,
206 struct sock_exterr_skb *serr)
207{
208 struct sock_extended_err *ee;
209 int err;
210
211 _enter("");
212
213 ee = &serr->ee;
214
215 err = ee->ee_errno;
216
217 switch (ee->ee_origin) {
218 case SO_EE_ORIGIN_ICMP:
219 switch (ee->ee_type) {
220 case ICMP_DEST_UNREACH:
221 switch (ee->ee_code) {
222 case ICMP_NET_UNREACH:
223 _net("Rx Received ICMP Network Unreachable");
224 break;
225 case ICMP_HOST_UNREACH:
226 _net("Rx Received ICMP Host Unreachable");
227 break;
228 case ICMP_PORT_UNREACH:
229 _net("Rx Received ICMP Port Unreachable");
230 break;
231 case ICMP_NET_UNKNOWN:
232 _net("Rx Received ICMP Unknown Network");
233 break;
234 case ICMP_HOST_UNKNOWN:
235 _net("Rx Received ICMP Unknown Host");
236 break;
237 default:
238 _net("Rx Received ICMP DestUnreach code=%u",
239 ee->ee_code);
240 break;
241 }
242 break;
243
244 case ICMP_TIME_EXCEEDED:
245 _net("Rx Received ICMP TTL Exceeded");
246 break;
247
248 default:
249 _proto("Rx Received ICMP error { type=%u code=%u }",
250 ee->ee_type, ee->ee_code);
251 break;
252 }
253 break;
254
255 case SO_EE_ORIGIN_NONE:
256 case SO_EE_ORIGIN_LOCAL:
257 _proto("Rx Received local error { error=%d }", err);
258 err += RXRPC_LOCAL_ERROR_OFFSET;
259 break;
260
261 case SO_EE_ORIGIN_ICMP6:
262 default:
263 _proto("Rx Received error report { orig=%u }", ee->ee_origin);
264 break;
265 }
266
267 peer->error_report = err;
268}
269
270/*
271 * Distribute an error that occurred on a peer
272 */
273void rxrpc_peer_error_distributor(struct work_struct *work)
274{
275 struct rxrpc_peer *peer =
276 container_of(work, struct rxrpc_peer, error_distributor);
277 struct rxrpc_call *call;
278 enum rxrpc_call_completion compl;
279 int error;
280
281 _enter("");
282
283 error = READ_ONCE(peer->error_report);
284 if (error < RXRPC_LOCAL_ERROR_OFFSET) {
285 compl = RXRPC_CALL_NETWORK_ERROR;
286 } else {
287 compl = RXRPC_CALL_LOCAL_ERROR;
288 error -= RXRPC_LOCAL_ERROR_OFFSET;
289 }
290
291 _debug("ISSUE ERROR %s %d", rxrpc_call_completions[compl], error);
292
293 spin_lock_bh(&peer->lock);
294
295 while (!hlist_empty(&peer->error_targets)) {
296 call = hlist_entry(peer->error_targets.first,
297 struct rxrpc_call, error_link);
298 hlist_del_init(&call->error_link);
299 rxrpc_see_call(call);
300
301 if (rxrpc_set_call_completion(call, compl, 0, -error))
302 rxrpc_notify_socket(call);
303 }
304
305 spin_unlock_bh(&peer->lock);
306
307 rxrpc_put_peer(peer);
308 _leave("");
309}
310
311/*
312 * Add RTT information to cache. This is called in softirq mode and has
313 * exclusive access to the peer RTT data.
314 */
315void rxrpc_peer_add_rtt(struct rxrpc_call *call, enum rxrpc_rtt_rx_trace why,
316 rxrpc_serial_t send_serial, rxrpc_serial_t resp_serial,
317 ktime_t send_time, ktime_t resp_time)
318{
319 struct rxrpc_peer *peer = call->peer;
320 s64 rtt;
321 u64 sum = peer->rtt_sum, avg;
322 u8 cursor = peer->rtt_cursor, usage = peer->rtt_usage;
323
324 rtt = ktime_to_ns(ktime_sub(resp_time, send_time));
325 if (rtt < 0)
326 return;
327
328 /* Replace the oldest datum in the RTT buffer */
329 sum -= peer->rtt_cache[cursor];
330 sum += rtt;
331 peer->rtt_cache[cursor] = rtt;
332 peer->rtt_cursor = (cursor + 1) & (RXRPC_RTT_CACHE_SIZE - 1);
333 peer->rtt_sum = sum;
334 if (usage < RXRPC_RTT_CACHE_SIZE) {
335 usage++;
336 peer->rtt_usage = usage;
337 }
338
339 /* Now recalculate the average */
340 if (usage == RXRPC_RTT_CACHE_SIZE) {
341 avg = sum / RXRPC_RTT_CACHE_SIZE;
342 } else {
343 avg = sum;
344 do_div(avg, usage);
345 }
346
347 peer->rtt = avg;
348 trace_rxrpc_rtt_rx(call, why, send_serial, resp_serial, rtt,
349 usage, avg);
350}
351
352/*
353 * Perform keep-alive pings with VERSION packets to keep any NAT alive.
354 */
355void rxrpc_peer_keepalive_worker(struct work_struct *work)
356{
357 struct rxrpc_net *rxnet =
358 container_of(work, struct rxrpc_net, peer_keepalive_work);
359 struct rxrpc_peer *peer;
360 unsigned long delay;
361 ktime_t base, now = ktime_get_real();
362 s64 diff;
363 u8 cursor, slot;
364
365 base = rxnet->peer_keepalive_base;
366 cursor = rxnet->peer_keepalive_cursor;
367
368 _enter("%u,%lld", cursor, ktime_sub(now, base));
369
370next_bucket:
371 diff = ktime_to_ns(ktime_sub(now, base));
372 if (diff < 0)
373 goto resched;
374
375 _debug("at %u", cursor);
376 spin_lock_bh(&rxnet->peer_hash_lock);
377next_peer:
378 if (!rxnet->live) {
379 spin_unlock_bh(&rxnet->peer_hash_lock);
380 goto out;
381 }
382
383 /* Everything in the bucket at the cursor is processed this second; the
384 * bucket at cursor + 1 goes now + 1s and so on...
385 */
386 if (hlist_empty(&rxnet->peer_keepalive[cursor])) {
387 if (hlist_empty(&rxnet->peer_keepalive_new)) {
388 spin_unlock_bh(&rxnet->peer_hash_lock);
389 goto emptied_bucket;
390 }
391
392 hlist_move_list(&rxnet->peer_keepalive_new,
393 &rxnet->peer_keepalive[cursor]);
394 }
395
396 peer = hlist_entry(rxnet->peer_keepalive[cursor].first,
397 struct rxrpc_peer, keepalive_link);
398 hlist_del_init(&peer->keepalive_link);
399 if (!rxrpc_get_peer_maybe(peer))
400 goto next_peer;
401
402 spin_unlock_bh(&rxnet->peer_hash_lock);
403
404 _debug("peer %u {%pISp}", peer->debug_id, &peer->srx.transport);
405
406recalc:
407 diff = ktime_divns(ktime_sub(peer->last_tx_at, base), NSEC_PER_SEC);
408 if (diff < -30 || diff > 30)
409 goto send; /* LSW of 64-bit time probably wrapped on 32-bit */
410 diff += RXRPC_KEEPALIVE_TIME - 1;
411 if (diff < 0)
412 goto send;
413
414 slot = (diff > RXRPC_KEEPALIVE_TIME - 1) ? RXRPC_KEEPALIVE_TIME - 1 : diff;
415 if (slot == 0)
416 goto send;
417
418 /* A transmission to this peer occurred since last we examined it so
419 * put it into the appropriate future bucket.
420 */
421 slot = (slot + cursor) % ARRAY_SIZE(rxnet->peer_keepalive);
422 spin_lock_bh(&rxnet->peer_hash_lock);
423 hlist_add_head(&peer->keepalive_link, &rxnet->peer_keepalive[slot]);
424 rxrpc_put_peer(peer);
425 goto next_peer;
426
427send:
428 rxrpc_send_keepalive(peer);
429 now = ktime_get_real();
430 goto recalc;
431
432emptied_bucket:
433 cursor++;
434 if (cursor >= ARRAY_SIZE(rxnet->peer_keepalive))
435 cursor = 0;
436 base = ktime_add_ns(base, NSEC_PER_SEC);
437 goto next_bucket;
438
439resched:
440 rxnet->peer_keepalive_base = base;
441 rxnet->peer_keepalive_cursor = cursor;
442 delay = nsecs_to_jiffies(-diff) + 1;
443 timer_reduce(&rxnet->peer_keepalive_timer, jiffies + delay);
444out:
445 _leave("");
446}