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