Merge branch 'maint'
[paraslash.git] / udp_send.c
1 /* Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
2
3 /** \file udp_send.c Para_server's udp sender. */
4
5 #include <netinet/in.h>
6 #include <sys/socket.h>
7 #include <regex.h>
8 #include <sys/types.h>
9 #include <netinet/udp.h>
10 #include <net/if.h>
11 #include <arpa/inet.h>
12 #include <sys/un.h>
13 #include <netdb.h>
14 #include <lopsub.h>
15
16 #include "server.lsg.h"
17 #include "para.h"
18 #include "error.h"
19 #include "string.h"
20 #include "afh.h"
21 #include "net.h"
22 #include "server.h"
23 #include "list.h"
24 #include "send.h"
25 #include "sched.h"
26 #include "vss.h"
27 #include "portable_io.h"
28 #include "fd.h"
29 #include "close_on_fork.h"
30
31 /**
32 * Time window during which ICMP Destination/Port Unreachable messages are
33 * ignored, covering transient receiver problems such as restarting the
34 * client, rebooting, reconfiguration, or handover.
35 */
36 #define UDP_MAX_UNREACHABLE_TIME 30
37
38 /** Describes one entry in the list of targets for the udp sender. */
39 struct udp_target {
40 /** Track time (seconds) of last ICMP Port Unreachable error */
41 time_t last_unreachable;
42 /** The opaque structure returned by vss_add_fec_client(). */
43 struct fec_client *fc;
44 /** The FEC parameters for this target. */
45 struct fec_client_parms fcp;
46 /** Whether we already sent the FEC eof packet to this target. */
47 bool sent_fec_eof;
48 };
49
50 static struct list_head targets;
51 static int sender_status;
52
53 static void udp_close_target(struct sender_client *sc)
54 {
55 const char *buf;
56 size_t len;
57 struct udp_target *ut = sc->private_data;
58
59 if (process_is_command_handler())
60 return;
61 if (ut->sent_fec_eof)
62 return;
63 PARA_INFO_LOG("sending FEC EOF\n");
64 len = vss_get_fec_eof_packet(&buf);
65 /* Ignore write() errors since we are closing the target anyway. */
66 if (write(sc->fd, buf, len))
67 do_nothing; /* avoid "ignoring return value" warning */
68 ut->sent_fec_eof = true;
69 }
70
71 static void udp_delete_target(struct sender_client *sc, const char *msg)
72 {
73 struct udp_target *ut = sc->private_data;
74
75 if (!process_is_command_handler())
76 PARA_NOTICE_LOG("deleting %s (%s) from list\n", sc->name, msg);
77 udp_close_target(sc);
78 /* command handlers already called close_listed_fds() */
79 if (!process_is_command_handler()) {
80 close(sc->fd);
81 del_close_on_fork_list(sc->fd);
82 }
83 vss_del_fec_client(ut->fc);
84 list_del(&sc->node);
85 free(sc->name);
86 free(sc);
87 free(ut);
88 }
89
90 /**
91 * Perform AF-independent multicast sender setup.
92 *
93 * \param sc The connected sender client.
94 *
95 * \return Zero if okay, negative on error.
96 */
97 static int mcast_sender_setup(struct sender_client *sc)
98 {
99 struct sockaddr_storage ss;
100 socklen_t sslen = sizeof(ss);
101 int ttl = OPT_INT32_VAL(UDP_TTL), id = 0;
102 const int on = 1;
103
104 if (OPT_GIVEN(UDP_MCAST_IFACE)) {
105 const char *iface = OPT_STRING_VAL(UDP_MCAST_IFACE);
106
107 id = if_nametoindex(iface);
108 if (id == 0)
109 PARA_WARNING_LOG("could not resolve interface '%s', "
110 "using default", iface);
111 }
112
113 if (getpeername(sc->fd, (struct sockaddr *)&ss, &sslen) < 0)
114 goto err;
115 assert(ss.ss_family == AF_INET || ss.ss_family == AF_INET6);
116
117 /* RFC 3493, 5.2: -1 means 'use kernel default' */
118 if (ttl < 0 || ttl > 255)
119 ttl = -1;
120
121 switch (ss.ss_family) {
122 case AF_INET:
123 if (!IN_MULTICAST(htonl(((struct sockaddr_in *)&ss)->sin_addr.s_addr)))
124 return 0;
125 if (id != 0) {
126 #ifdef HAVE_IP_MREQN
127 struct ip_mreqn mn;
128
129 memset(&mn, 0, sizeof(mn));
130 mn.imr_ifindex = id;
131 if (setsockopt(sc->fd, IPPROTO_IP, IP_MULTICAST_IF, &mn, sizeof(mn)) < 0)
132 goto err;
133 #else
134 PARA_ERROR_LOG("No support for setting outgoing IPv4 mcast interface.");
135 #endif
136 }
137 /*
138 * Enable receiving multicast messages generated on the local host
139 * At least on Linux, this is enabled by default.
140 */
141 if (setsockopt(sc->fd, IPPROTO_IP, IP_MULTICAST_LOOP, &on, sizeof(on)) < 0)
142 break;
143
144 /* Default: use local subnet (do not flood out into the WAN) */
145 if (ttl == -1)
146 ttl = 1;
147 if (setsockopt(sc->fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) < 0)
148 break;
149 return 0;
150 case AF_INET6:
151 if (!IN6_IS_ADDR_MULTICAST(&((struct sockaddr_in6 *)&ss)->sin6_addr))
152 return 0;
153 if (id != 0 &&
154 setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &id, sizeof(id)) < 0)
155 break;
156 if (setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_LOOP, &on, sizeof(on)) < 0)
157 break;
158 if (setsockopt(sc->fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &ttl, sizeof(ttl)) < 0)
159 break;
160 return 0;
161 }
162 err:
163 return -ERRNO_TO_PARA_ERROR(errno);
164 }
165
166 static void udp_shutdown_targets(void)
167 {
168 struct sender_client *sc, *tmp;
169 list_for_each_entry_safe(sc, tmp, &targets, node)
170 udp_close_target(sc);
171 }
172
173 static void udp_shutdown(void)
174 {
175 struct sender_client *sc, *tmp;
176 list_for_each_entry_safe(sc, tmp, &targets, node)
177 udp_delete_target(sc, "shutdown");
178 }
179
180 static int udp_resolve_target(const char *url, struct sender_command_data *scd)
181 {
182 const char *result;
183 int ret, port;
184
185 ret = parse_fec_url(url, scd);
186 if (ret)
187 return ret;
188 port = scd->port > 0 ? scd->port : OPT_UINT32_VAL(UDP_DEFAULT_PORT);
189
190 ret = para_connect_simple(IPPROTO_UDP, scd->host, port);
191 if (ret < 0)
192 return ret;
193
194 result = remote_name(ret);
195 close(ret);
196
197 if (!parse_url(result, scd->host, sizeof(scd->host), &scd->port))
198 return -E_ADDRESS_LOOKUP;
199 return 1;
200 }
201
202 static int udp_com_on(__a_unused struct sender_command_data *scd)
203 {
204 sender_status = SENDER_on;
205 return 1;
206 }
207
208 static int udp_com_off(__a_unused struct sender_command_data *scd)
209 {
210 udp_shutdown_targets();
211 sender_status = SENDER_off;
212 return 1;
213 }
214
215 static struct sender_client *udp_lookup_target(struct sender_command_data *scd)
216 {
217 struct sender_client *sc, *tmp;
218 char host[MAX_HOSTLEN];
219 int32_t port;
220
221 list_for_each_entry_safe(sc, tmp, &targets, node) {
222 parse_url(sc->name, host, sizeof(host), &port);
223
224 /* Unspecified port means wildcard port match */
225 if (scd->port > 0 && scd->port != port)
226 continue;
227 if (strcmp(host, scd->host))
228 continue;
229 return sc;
230 }
231 return NULL;
232 }
233
234 static int udp_com_delete(struct sender_command_data *scd)
235 {
236 struct sender_client *sc = udp_lookup_target(scd);
237
238 if (sc) {
239 udp_delete_target(sc, "com_delete");
240 return 1;
241 }
242 PARA_NOTICE_LOG("not deleting non-existing target '%s'\n", scd->host);
243 return -E_TARGET_NOT_FOUND;
244 }
245
246 /** Initialize UDP session and set maximum payload size. */
247 static int udp_init_fec(struct sender_client *sc)
248 {
249 struct udp_target *ut = sc->private_data;
250 int mps;
251
252 PARA_INFO_LOG("sending to udp %s\n", sc->name);
253 ut->sent_fec_eof = false;
254 mps = generic_max_transport_msg_size(sc->fd) - sizeof(struct udphdr);
255 PARA_INFO_LOG("current MPS = %d bytes\n", mps);
256 return mps;
257 }
258
259 /** Check and clear socket error if any. */
260 static int udp_check_socket_state(struct sender_client *sc)
261 {
262 struct udp_target *ut = sc->private_data;
263 int ret;
264 socklen_t errlen = sizeof(ret);
265
266 if (getsockopt(sc->fd, SOL_SOCKET, SO_ERROR, &ret, &errlen) < 0) {
267 PARA_ERROR_LOG("SO_ERROR failed: %s\n", strerror(ret));
268 return 0;
269 } else if (ret == 0) {
270 return 0;
271 } else if (ret == ECONNREFUSED) {
272 time_t dist = now->tv_sec - ut->last_unreachable;
273
274 if (dist <= UDP_MAX_UNREACHABLE_TIME) {
275 return 0;
276 } else if (dist > 2 * UDP_MAX_UNREACHABLE_TIME) {
277 ut->last_unreachable = now->tv_sec;
278 return 0;
279 } else {
280 /*
281 * unreachable_time < dist <= 2 * unreachable_time
282 * No errors are allowed during this time window.
283 */
284 PARA_NOTICE_LOG("Evicting %s after %d seconds "
285 "of connection errors.\n",
286 sc->name, (int)dist);
287 }
288 }
289 return -ERRNO_TO_PARA_ERROR(ret);
290 }
291
292 static void udp_send_fec(struct sender_client *sc, char *buf, size_t len)
293 {
294 int ret;
295
296 if (sender_status == SENDER_off)
297 return;
298 if (len == 0)
299 return;
300 ret = udp_check_socket_state(sc);
301 if (ret < 0)
302 goto fail;
303 ret = xwrite(sc->fd, buf, len);
304 if (ret == -ERRNO_TO_PARA_ERROR(ECONNREFUSED)) {
305 /*
306 * Happens if meanwhile an ICMP Destination / Port Unreachable
307 * has arrived. Ignore, persistent errors will be caught above.
308 */
309 ret = 0;
310 }
311 if (ret < 0)
312 goto fail;
313 return;
314 fail:
315 udp_delete_target(sc, para_strerror(-ret));
316 }
317
318 static int udp_com_add(struct sender_command_data *scd)
319 {
320 int ret;
321 struct udp_target *ut;
322 struct sender_client *sc = udp_lookup_target(scd);
323
324 if (sc) {
325 PARA_NOTICE_LOG("target %s already exists - not adding it\n",
326 sc->name);
327 return -E_TARGET_EXISTS;
328 }
329 ut = para_calloc(sizeof(*ut));
330 sc = para_calloc(sizeof(*sc));
331 ut->fcp.slices_per_group = scd->slices_per_group;
332 ut->fcp.data_slices_per_group = scd->data_slices_per_group;
333 ut->fcp.init_fec = udp_init_fec;
334 ut->fcp.send_fec = udp_send_fec;
335 ut->fcp.need_periodic_header = true;
336
337 sc->private_data = ut;
338 sc->fd = -1;
339 ret = para_connect_simple(IPPROTO_UDP, scd->host, scd->port);
340 if (ret < 0)
341 goto err;
342 sc->fd = ret;
343
344 ret = mcast_sender_setup(sc);
345 if (ret < 0)
346 goto err;
347 ret = mark_fd_nonblocking(sc->fd);
348 if (ret < 0)
349 goto err;
350 sc->name = para_strdup(remote_name(sc->fd));
351 PARA_INFO_LOG("adding to target list (%s)\n", sc->name);
352 ut->fc = vss_add_fec_client(sc, &ut->fcp);
353 para_list_add(&sc->node, &targets);
354 add_close_on_fork_list(sc->fd);
355 return 1;
356 err:
357 if (sc->fd >= 0)
358 close(sc->fd);
359 PARA_NOTICE_LOG("failed to set up %s:%d (%s)- not adding it\n",
360 scd->host, scd->port, para_strerror(-ret));
361 free(sc);
362 free(ut);
363 return ret;
364 }
365
366 static char *udp_status(void)
367 {
368 struct sender_client *sc;
369 char *ret, *tgts = NULL;
370
371 list_for_each_entry(sc, &targets, node) {
372 struct udp_target *ut = sc->private_data;
373 char *tmp = make_message("%s%s/%u:%u ",
374 tgts ? : "", sc->name,
375 ut->fcp.data_slices_per_group,
376 ut->fcp.slices_per_group
377 );
378 free(tgts);
379 tgts = tmp;
380 }
381 ret = make_message(
382 "status: %s\n"
383 "port: %s\n"
384 "targets: %s\n",
385 (sender_status == SENDER_on)? "on" : "off",
386 stringify_port(OPT_UINT32_VAL(UDP_DEFAULT_PORT), "udp"),
387 tgts? tgts : "(none)"
388 );
389 free(tgts);
390 return ret;
391 }
392
393 static void udp_init_target_list(void)
394 {
395 struct sender_command_data scd;
396 int i;
397
398 init_list_head(&targets);
399 for (i = 0; i < OPT_GIVEN(UDP_TARGET); i++) {
400 const char *arg = lls_string_val(i, OPT_RESULT(UDP_TARGET));
401 if (udp_resolve_target(arg, &scd) < 0)
402 PARA_CRIT_LOG("not adding requested target '%s'\n",
403 arg);
404 else
405 udp_com_add(&scd);
406 }
407 }
408
409 static char *udp_help(void)
410 {
411 return make_message(
412 "usage: {on|off}\n"
413 "usage: {add|delete} ip_address[:port][/[packet_size:]k:n]\n"
414 " - k is the number of data slices per FEC group\n"
415 " - n is the total number of slices in a FEC group\n"
416 " - packet_size reduces the slice size below path MTU\n\n"
417 "examples: add 224.0.1.38:1500 (IPv4 multicast)\n"
418 " add 224.0.1.38:8080/14:16 (explicit FEC)\n"
419 " add 10.10.1.42 (using default port)\n"
420 " add [FF05::42]:1500 (IPv6 multicast)\n"
421 " add [::1] (IPv6 localhost/default port)\n"
422 " delete myhost.net (host with port wildcard)\n"
423 " delete 10.1.2.3:456 (IPv4 with explicit port)\n"
424 " delete [badc0de::1] (IPv6 with port wildcard)\n"
425 );
426 }
427
428 /* Initialize the list of udp targets. */
429 static void udp_send_init(void)
430 {
431 init_list_head(&targets);
432 sender_status = SENDER_off;
433 udp_init_target_list();
434 if (!OPT_GIVEN(UDP_NO_AUTOSTART))
435 sender_status = SENDER_on;
436 PARA_DEBUG_LOG("udp sender init complete\n");
437 }
438
439 /**
440 * The UDP sender.
441 *
442 * In contrast to the other senders the UDP sender is active in the sense that
443 * it initiates the network connection according to its list of targets rather
444 * than passively waiting for clients to connect. Like DCCP streams, UDP
445 * streams are always sent FEC-encoded. The UDP sender is the only sender which
446 * supports IP multicasting.
447 */
448 const struct sender udp_sender = {
449 .name = "udp",
450 .init = udp_send_init,
451 .shutdown = udp_shutdown,
452 .shutdown_clients = udp_shutdown_targets,
453 .resolve_target = udp_resolve_target,
454 .client_cmds = {
455 [SENDER_on] = udp_com_on,
456 [SENDER_off] = udp_com_off,
457 [SENDER_add] = udp_com_add,
458 [SENDER_delete] = udp_com_delete,
459 },
460 .help = udp_help,
461 .status = udp_status,
462 };