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