1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
|
/* SPDX-License-Identifier: LGPL-2.1-or-later */
/***
Copyright © 2014 Intel Corporation. All rights reserved.
***/
#include <netinet/icmp6.h>
#include <netinet/in.h>
#include "sd-ndisc.h"
#include "alloc-util.h"
#include "event-util.h"
#include "fd-util.h"
#include "icmp6-util.h"
#include "in-addr-util.h"
#include "memory-util.h"
#include "ndisc-internal.h"
#include "ndisc-router.h"
#include "network-common.h"
#include "random-util.h"
#include "socket-util.h"
#include "string-table.h"
#include "string-util.h"
#define NDISC_TIMEOUT_NO_RA_USEC (NDISC_ROUTER_SOLICITATION_INTERVAL * NDISC_MAX_ROUTER_SOLICITATIONS)
static const char * const ndisc_event_table[_SD_NDISC_EVENT_MAX] = {
[SD_NDISC_EVENT_TIMEOUT] = "timeout",
[SD_NDISC_EVENT_ROUTER] = "router",
};
DEFINE_STRING_TABLE_LOOKUP(ndisc_event, sd_ndisc_event_t);
static void ndisc_callback(sd_ndisc *ndisc, sd_ndisc_event_t event, sd_ndisc_router *rt) {
assert(ndisc);
assert(event >= 0 && event < _SD_NDISC_EVENT_MAX);
if (!ndisc->callback)
return (void) log_ndisc(ndisc, "Received '%s' event.", ndisc_event_to_string(event));
log_ndisc(ndisc, "Invoking callback for '%s' event.", ndisc_event_to_string(event));
ndisc->callback(ndisc, event, rt, ndisc->userdata);
}
int sd_ndisc_set_callback(
sd_ndisc *nd,
sd_ndisc_callback_t callback,
void *userdata) {
assert_return(nd, -EINVAL);
nd->callback = callback;
nd->userdata = userdata;
return 0;
}
int sd_ndisc_set_ifindex(sd_ndisc *nd, int ifindex) {
assert_return(nd, -EINVAL);
assert_return(ifindex > 0, -EINVAL);
assert_return(nd->fd < 0, -EBUSY);
nd->ifindex = ifindex;
return 0;
}
int sd_ndisc_set_ifname(sd_ndisc *nd, const char *ifname) {
assert_return(nd, -EINVAL);
assert_return(ifname, -EINVAL);
if (!ifname_valid_full(ifname, IFNAME_VALID_ALTERNATIVE))
return -EINVAL;
return free_and_strdup(&nd->ifname, ifname);
}
int sd_ndisc_get_ifname(sd_ndisc *nd, const char **ret) {
int r;
assert_return(nd, -EINVAL);
r = get_ifname(nd->ifindex, &nd->ifname);
if (r < 0)
return r;
if (ret)
*ret = nd->ifname;
return 0;
}
int sd_ndisc_set_mac(sd_ndisc *nd, const struct ether_addr *mac_addr) {
assert_return(nd, -EINVAL);
if (mac_addr)
nd->mac_addr = *mac_addr;
else
zero(nd->mac_addr);
return 0;
}
int sd_ndisc_attach_event(sd_ndisc *nd, sd_event *event, int64_t priority) {
int r;
assert_return(nd, -EINVAL);
assert_return(nd->fd < 0, -EBUSY);
assert_return(!nd->event, -EBUSY);
if (event)
nd->event = sd_event_ref(event);
else {
r = sd_event_default(&nd->event);
if (r < 0)
return 0;
}
nd->event_priority = priority;
return 0;
}
int sd_ndisc_detach_event(sd_ndisc *nd) {
assert_return(nd, -EINVAL);
assert_return(nd->fd < 0, -EBUSY);
nd->event = sd_event_unref(nd->event);
return 0;
}
sd_event *sd_ndisc_get_event(sd_ndisc *nd) {
assert_return(nd, NULL);
return nd->event;
}
static void ndisc_reset(sd_ndisc *nd) {
assert(nd);
(void) event_source_disable(nd->timeout_event_source);
(void) event_source_disable(nd->timeout_no_ra);
nd->retransmit_time = 0;
nd->recv_event_source = sd_event_source_disable_unref(nd->recv_event_source);
nd->fd = safe_close(nd->fd);
}
static sd_ndisc *ndisc_free(sd_ndisc *nd) {
assert(nd);
ndisc_reset(nd);
sd_event_source_unref(nd->timeout_event_source);
sd_event_source_unref(nd->timeout_no_ra);
sd_ndisc_detach_event(nd);
free(nd->ifname);
return mfree(nd);
}
DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_ndisc, sd_ndisc, ndisc_free);
int sd_ndisc_new(sd_ndisc **ret) {
_cleanup_(sd_ndisc_unrefp) sd_ndisc *nd = NULL;
assert_return(ret, -EINVAL);
nd = new(sd_ndisc, 1);
if (!nd)
return -ENOMEM;
*nd = (sd_ndisc) {
.n_ref = 1,
.fd = -EBADF,
};
*ret = TAKE_PTR(nd);
return 0;
}
static int ndisc_handle_datagram(sd_ndisc *nd, sd_ndisc_router *rt) {
int r;
assert(nd);
assert(rt);
r = ndisc_router_parse(nd, rt);
if (r < 0)
return r;
log_ndisc(nd, "Received Router Advertisement: flags %s preference %s lifetime %s",
rt->flags & ND_RA_FLAG_MANAGED ? "MANAGED" : rt->flags & ND_RA_FLAG_OTHER ? "OTHER" : "none",
rt->preference == SD_NDISC_PREFERENCE_HIGH ? "high" : rt->preference == SD_NDISC_PREFERENCE_LOW ? "low" : "medium",
FORMAT_TIMESPAN(rt->lifetime_usec, USEC_PER_SEC));
ndisc_callback(nd, SD_NDISC_EVENT_ROUTER, rt);
return 0;
}
static int ndisc_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
_cleanup_(sd_ndisc_router_unrefp) sd_ndisc_router *rt = NULL;
sd_ndisc *nd = ASSERT_PTR(userdata);
ssize_t buflen;
int r;
assert(s);
assert(nd->event);
buflen = next_datagram_size_fd(fd);
if (ERRNO_IS_NEG_TRANSIENT(buflen) || ERRNO_IS_NEG_DISCONNECT(buflen))
return 0;
if (buflen < 0) {
log_ndisc_errno(nd, buflen, "Failed to determine datagram size to read, ignoring: %m");
return 0;
}
rt = ndisc_router_new(buflen);
if (!rt)
return -ENOMEM;
r = icmp6_receive(fd, NDISC_ROUTER_RAW(rt), rt->raw_size, &rt->address, &rt->timestamp);
if (ERRNO_IS_NEG_TRANSIENT(r) || ERRNO_IS_NEG_DISCONNECT(r))
return 0;
if (r < 0)
switch (r) {
case -EADDRNOTAVAIL:
log_ndisc(nd, "Received RA from neither link-local nor null address. Ignoring.");
return 0;
case -EMULTIHOP:
log_ndisc(nd, "Received RA with invalid hop limit. Ignoring.");
return 0;
case -EPFNOSUPPORT:
log_ndisc(nd, "Received invalid source address from ICMPv6 socket. Ignoring.");
return 0;
default:
log_ndisc_errno(nd, r, "Unexpected error while reading from ICMPv6, ignoring: %m");
return 0;
}
/* The function icmp6_receive() accepts the null source address, but RFC 4861 Section 6.1.2 states
* that hosts MUST discard messages with the null source address. */
if (in6_addr_is_null(&rt->address))
log_ndisc(nd, "Received RA from null address. Ignoring.");
(void) event_source_disable(nd->timeout_event_source);
(void) ndisc_handle_datagram(nd, rt);
return 0;
}
static usec_t ndisc_timeout_compute_random(usec_t val) {
/* compute a time that is random within ±10% of the given value */
return val - val / 10 +
(random_u64() % (2 * USEC_PER_SEC)) * val / 10 / USEC_PER_SEC;
}
static int ndisc_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
sd_ndisc *nd = ASSERT_PTR(userdata);
usec_t time_now;
int r;
assert(s);
assert(nd->event);
assert_se(sd_event_now(nd->event, CLOCK_BOOTTIME, &time_now) >= 0);
if (!nd->retransmit_time)
nd->retransmit_time = ndisc_timeout_compute_random(NDISC_ROUTER_SOLICITATION_INTERVAL);
else {
if (nd->retransmit_time > NDISC_MAX_ROUTER_SOLICITATION_INTERVAL / 2)
nd->retransmit_time = ndisc_timeout_compute_random(NDISC_MAX_ROUTER_SOLICITATION_INTERVAL);
else
nd->retransmit_time += ndisc_timeout_compute_random(nd->retransmit_time);
}
r = event_reset_time(nd->event, &nd->timeout_event_source,
CLOCK_BOOTTIME,
time_now + nd->retransmit_time, 10 * USEC_PER_MSEC,
ndisc_timeout, nd,
nd->event_priority, "ndisc-timeout-no-ra", true);
if (r < 0)
goto fail;
r = icmp6_send_router_solicitation(nd->fd, &nd->mac_addr);
if (r < 0)
log_ndisc_errno(nd, r, "Failed to send Router Solicitation, next solicitation in %s, ignoring: %m",
FORMAT_TIMESPAN(nd->retransmit_time, USEC_PER_SEC));
else
log_ndisc(nd, "Sent Router Solicitation, next solicitation in %s",
FORMAT_TIMESPAN(nd->retransmit_time, USEC_PER_SEC));
return 0;
fail:
(void) sd_ndisc_stop(nd);
return 0;
}
static int ndisc_timeout_no_ra(sd_event_source *s, uint64_t usec, void *userdata) {
sd_ndisc *nd = ASSERT_PTR(userdata);
assert(s);
log_ndisc(nd, "No RA received before link confirmation timeout");
(void) event_source_disable(nd->timeout_no_ra);
ndisc_callback(nd, SD_NDISC_EVENT_TIMEOUT, NULL);
return 0;
}
int sd_ndisc_stop(sd_ndisc *nd) {
if (!nd)
return 0;
if (nd->fd < 0)
return 0;
log_ndisc(nd, "Stopping IPv6 Router Solicitation client");
ndisc_reset(nd);
return 1;
}
int sd_ndisc_start(sd_ndisc *nd) {
int r;
usec_t time_now;
assert_return(nd, -EINVAL);
assert_return(nd->event, -EINVAL);
assert_return(nd->ifindex > 0, -EINVAL);
if (nd->fd >= 0)
return 0;
assert(!nd->recv_event_source);
r = sd_event_now(nd->event, CLOCK_BOOTTIME, &time_now);
if (r < 0)
goto fail;
nd->fd = icmp6_bind_router_solicitation(nd->ifindex);
if (nd->fd < 0)
return nd->fd;
r = sd_event_add_io(nd->event, &nd->recv_event_source, nd->fd, EPOLLIN, ndisc_recv, nd);
if (r < 0)
goto fail;
r = sd_event_source_set_priority(nd->recv_event_source, nd->event_priority);
if (r < 0)
goto fail;
(void) sd_event_source_set_description(nd->recv_event_source, "ndisc-receive-message");
r = event_reset_time(nd->event, &nd->timeout_event_source,
CLOCK_BOOTTIME,
time_now + USEC_PER_SEC / 2, 1 * USEC_PER_SEC, /* See RFC 8415 sec. 18.2.1 */
ndisc_timeout, nd,
nd->event_priority, "ndisc-timeout", true);
if (r < 0)
goto fail;
r = event_reset_time(nd->event, &nd->timeout_no_ra,
CLOCK_BOOTTIME,
time_now + NDISC_TIMEOUT_NO_RA_USEC, 10 * USEC_PER_MSEC,
ndisc_timeout_no_ra, nd,
nd->event_priority, "ndisc-timeout-no-ra", true);
if (r < 0)
goto fail;
log_ndisc(nd, "Started IPv6 Router Solicitation client");
return 1;
fail:
ndisc_reset(nd);
return r;
}
|