vss: Improve error diagnostics.
[paraslash.git] / send_common.c
1 /* Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
2
3 /** \file send_common.c Functions used by more than one paraslash sender. */
4
5 #include <netinet/in.h>
6 #include <sys/socket.h>
7 #include <regex.h>
8 #include <osl.h>
9 #include <arpa/inet.h>
10 #include <sys/un.h>
11 #include <netdb.h>
12 #include <lopsub.h>
13
14 #include "para.h"
15 #include "error.h"
16 #include "string.h"
17 #include "fd.h"
18 #include "net.h"
19 #include "list.h"
20 #include "afh.h"
21 #include "afs.h"
22 #include "server.h"
23 #include "acl.h"
24 #include "send.h"
25 #include "close_on_fork.h"
26 #include "chunk_queue.h"
27 #include "sched.h"
28 #include "vss.h"
29
30 /** Clients will be kicked if there are more than that many bytes pending. */
31 #define MAX_CQ_BYTES 40000
32
33 /**
34 * Shut down a client connected to a paraslash sender.
35 *
36 * \param sc The client to shut down.
37 * \param ss The sender whose clients are to be shut down.
38 *
39 * Close the file descriptor given by \a sc, remove it from the close-on-fork
40 * list, destroy the chunk queue of this client, delete the client from the
41 * list of connected clients and free the sender_client struct.
42 *
43 * \sa \ref shutdown_clients().
44 */
45 void shutdown_client(struct sender_client *sc, struct sender_status *ss)
46 {
47 PARA_INFO_LOG("shutting down %s on fd %d\n", sc->name, sc->fd);
48 free(sc->name);
49 if (!process_is_command_handler()) {
50 close(sc->fd);
51 del_close_on_fork_list(sc->fd);
52 }
53 cq_destroy(sc->cq);
54 list_del(&sc->node);
55 free(sc->private_data);
56 free(sc);
57 ss->num_clients--;
58 }
59
60 /**
61 * Shut down all clients connected to a paraslash sender.
62 *
63 * \param ss The sender whose clients are to be shut down.
64 *
65 * This just loops over all connected clients and calls shutdown_client()
66 * for each client.
67 */
68 void shutdown_clients(struct sender_status *ss)
69 {
70 struct sender_client *sc, *tmp;
71 list_for_each_entry_safe(sc, tmp, &ss->client_list, node)
72 shutdown_client(sc, ss);
73 }
74
75 /**
76 * Try to empty the chunk queue for this fd.
77 *
78 * \param fd The file descriptor.
79 * \param cq The list of queued chunks.
80 *
81 * \return Negative on errors, zero if not everything was sent, one otherwise.
82 */
83 int send_queued_chunks(int fd, struct chunk_queue *cq)
84 {
85 struct queued_chunk *qc;
86 while ((qc = cq_peek(cq))) {
87 const char *buf;
88 size_t len;
89 int ret;
90
91 cq_get(qc, &buf, &len);
92 ret = xwrite(fd, buf, len);
93 if (ret < 0)
94 return ret;
95 cq_update(cq, ret);
96 if (ret != len)
97 return 0;
98 cq_dequeue(cq);
99 }
100 return 1;
101 }
102
103 /**
104 * Initialize a struct sender status.
105 *
106 * \param ss The struct to initialize.
107 * \param acl_opt_result Contains array of --{http|dccp}-access arguments.
108 * \param listen_address_opt_result Where to listen on.
109 * \param default_port Used for addresses with no specified port.
110 * \param max_clients The maximal number of simultaneous connections.
111 * \param default_deny Whether a blacklist should be used for access control.
112 */
113 void init_sender_status(struct sender_status *ss,
114 const struct lls_opt_result *acl_opt_result,
115 const struct lls_opt_result *listen_address_opt_result,
116 int default_port, int max_clients, int default_deny)
117 {
118 int i;
119 unsigned n = lls_opt_given(listen_address_opt_result);
120
121 if (n == 0) {
122 ss->num_listen_fds = 1;
123 ss->listen_addresses = para_malloc(sizeof(char *));
124 ss->listen_addresses[0] = NULL;
125 ss->listen_fds = para_malloc(sizeof(int));
126 ss->listen_fds[0] = -1;
127 } else {
128 ss->num_listen_fds = n;
129 ss->listen_addresses = para_malloc(n * sizeof(char *));
130 ss->listen_fds = para_malloc(n * sizeof(int));
131 FOR_EACH_LISTEN_FD(i, ss) {
132 ss->listen_addresses[i] = para_strdup(lls_string_val(i,
133 listen_address_opt_result));
134 ss->listen_fds[i] = -1;
135 }
136 }
137 ss->default_port = default_port;
138
139 INIT_LIST_HEAD(&ss->client_list);
140 /* Initialize an access control list */
141 INIT_LIST_HEAD(&ss->acl);
142 for (i = 0; i < lls_opt_given(acl_opt_result); i++) {
143 const char *arg = lls_string_val(i, acl_opt_result);
144 char addr[16];
145 int mask;
146 if (!parse_cidr(arg, addr, sizeof(addr), &mask))
147 PARA_WARNING_LOG("ACL syntax error: %s, ignoring\n",
148 arg);
149 else
150 acl_add_entry(&ss->acl, addr, mask);
151 }
152 ss->num_clients = 0;
153 ss->max_clients = max_clients;
154 ss->default_deny = default_deny;
155 }
156
157 /**
158 * Deallocate all resources allocated in \ref init_sender_status().
159 *
160 * \param ss The structure whose components should be freed.
161 *
162 * This frees the dynamically allocated parts of the structure which was
163 * initialized by an earlier call to \ref init_sender_status(). It does *not*
164 * call free(ss), though.
165 */
166 void free_sender_status(const struct sender_status *ss)
167 {
168 int i;
169
170 free(ss->listen_fds);
171 FOR_EACH_LISTEN_FD(i, ss)
172 free(ss->listen_addresses[i]);
173 free(ss->listen_addresses);
174 }
175
176 /**
177 * Return a string containing the current status of a sender.
178 *
179 * \param ss The sender.
180 * \param name Used for printing the header line.
181 *
182 * \return The string printed in the "si" command.
183 */
184 char *generic_sender_status(struct sender_status *ss, const char *name)
185 {
186 char *clnts = NULL, *ret, *addr = NULL;
187 struct sender_client *sc, *tmp_sc;
188 unsigned n;
189 char *acl_contents = acl_get_contents(&ss->acl);
190
191 list_for_each_entry_safe(sc, tmp_sc, &ss->client_list, node) {
192 char *tmp = make_message("%s%s ", clnts? clnts : "", sc->name);
193 free(clnts);
194 clnts = tmp;
195 }
196 FOR_EACH_LISTEN_FD(n, ss) {
197 char *url = format_url(ss->listen_addresses[n], ss->default_port);
198 char *tmp = make_message("%s%s%s (fd %d)", addr?
199 addr : "", addr? ", " : "", url,
200 ss->listen_fds[n]);
201 free(url);
202 free(addr);
203 addr = tmp;
204 }
205 ret = make_message(
206 "listening address(es): %s\n"
207 "default port: %s\n"
208 "number of connected clients: %d\n"
209 "maximal number of clients: %d%s\n"
210 "connected clients: %s\n"
211 "access %s list: %s\n",
212 addr,
213 stringify_port(ss->default_port,
214 strcmp(name, "http")? "dccp" : "tcp"),
215 ss->num_clients,
216 ss->max_clients,
217 ss->max_clients > 0? "" : " (unlimited)",
218 clnts? clnts : "(none)",
219 ss->default_deny? "allow" : "deny",
220 acl_contents? acl_contents : "(empty)"
221 );
222 free(acl_contents);
223 free(clnts);
224 return ret;
225 }
226
227 /**
228 * Allow connections from the given range of IP addresses.
229 *
230 * \param scd Contains the IP and the netmask.
231 * \param ss The sender.
232 *
233 * \sa \ref generic_com_deny().
234 */
235 void generic_com_allow(struct sender_command_data *scd,
236 struct sender_status *ss)
237 {
238 acl_allow(scd->host, scd->netmask, &ss->acl, ss->default_deny);
239 }
240
241 /**
242 * Empty the access control list of a sender.
243 *
244 * \param acl The access control list of the sender.
245 *
246 * This is called from the ->shutdown methods of the http and the dccp sender.
247 */
248 void generic_acl_deplete(struct list_head *acl)
249 {
250 /*
251 * Since default_deny is false, the ACL is considered a blacklist. A
252 * netmask of zero matches any IP address, so this call empties the ACL.
253 */
254 acl_allow("0.0.0.0", 0 /* netmask */, acl, 0 /* default_deny */);
255 }
256
257 /**
258 * Deny connections from the given range of IP addresses.
259 *
260 * \param scd see \ref generic_com_allow().
261 * \param ss see \ref generic_com_allow().
262 *
263 * \sa \ref generic_com_allow().
264 */
265 void generic_com_deny(struct sender_command_data *scd,
266 struct sender_status *ss)
267 {
268 acl_deny(scd->host, scd->netmask, &ss->acl, ss->default_deny);
269 }
270
271 /**
272 * Activate a paraslash sender.
273 *
274 * \param ss The sender to activate.
275 * \param protocol layer4 type (IPPROTO_TCP or IPPROTO_DCCP).
276 *
277 * This opens a passive socket of given layer4 type, sets the resulting file
278 * descriptor to nonblocking mode and adds it to the close on fork list.
279 *
280 * Errors are logged but otherwise ignored.
281 */
282 void generic_com_on(struct sender_status *ss, unsigned protocol)
283 {
284 int ret;
285 unsigned n;
286
287 FOR_EACH_LISTEN_FD(n, ss) {
288 if (ss->listen_fds[n] >= 0)
289 continue;
290 ret = para_listen(protocol, ss->listen_addresses[n],
291 ss->default_port);
292 if (ret < 0) {
293 char *url = format_url(ss->listen_addresses[n],
294 ss->default_port);
295 PARA_ERROR_LOG("could not listen on %s %s: %s\n",
296 protocol == IPPROTO_TCP? "TCP" : "DCCP",
297 url, para_strerror(-ret));
298 free(url);
299 continue;
300 }
301 ss->listen_fds[n] = ret;
302 ret = mark_fd_nonblocking(ss->listen_fds[n]);
303 if (ret < 0) {
304 char *url = format_url(ss->listen_addresses[n],
305 ss->default_port);
306 PARA_ERROR_LOG("could not set %s socket fd for %s to "
307 "nonblocking mode: %s\n",
308 protocol == IPPROTO_TCP? "TCP" : "DCCP", url,
309 para_strerror(-ret));
310 free(url);
311 close(ss->listen_fds[n]);
312 ss->listen_fds[n] = -1;
313 continue;
314 }
315 add_close_on_fork_list(ss->listen_fds[n]);
316 }
317 }
318
319 /**
320 * Deactivate a paraslash sender.
321 *
322 * Shutdown all connected clients and stop listening on the TCP/DCCP socket.
323 *
324 * \param ss The sender to deactivate.
325 *
326 * \sa \ref del_close_on_fork_list(), \ref shutdown_clients().
327 */
328 void generic_com_off(struct sender_status *ss)
329 {
330 unsigned n;
331
332 FOR_EACH_LISTEN_FD(n, ss) {
333 if (ss->listen_fds[n] < 0)
334 return;
335 close(ss->listen_fds[n]);
336 del_close_on_fork_list(ss->listen_fds[n]);
337 shutdown_clients(ss);
338 ss->listen_fds[n] = -1;
339 }
340 }
341
342 /**
343 * Accept a connection on the socket(s) this server is listening on.
344 *
345 * \param ss The sender whose listening fd is ready for reading.
346 * \param rfds Passed to para_accept(),
347 *
348 * This accepts incoming connections on any of the listening sockets of the
349 * server. If there is a connection pending, the function
350 *
351 * - Checks whether the maximal number of connections are exceeded.
352 * - Sets \a fd to nonblocking mode.
353 * - Checks the acl of the sender to find out whether connections
354 * are allowed from the IP of the connecting peer.
355 * - Increases the number of connections for this sender.
356 * - Creates and initializes a new chunk queue for queuing network
357 * packets that can not be sent immediately.
358 * - Allocates a new struct sender_client and fills in its \a fd, \a cq
359 * and \a name members.
360 * - Adds \a fd to the list of connected clients for this sender.
361 * - Adds \a fd to the list of file descriptors that should be closed
362 * in the child process when the server calls fork().
363 *
364 * \return A pointer to the allocated sender_client structure on success, \p
365 * NULL on errors.
366 *
367 * \sa \ref para_accept(), \ref mark_fd_nonblocking(), \ref acl_check_access(),
368 * \ref cq_new(), \ref add_close_on_fork_list().
369 */
370 struct sender_client *accept_sender_client(struct sender_status *ss, fd_set *rfds)
371 {
372 struct sender_client *sc;
373 int fd, ret;
374 unsigned n;
375
376 FOR_EACH_LISTEN_FD(n, ss) {
377 if (ss->listen_fds[n] < 0)
378 continue;
379 ret = para_accept(ss->listen_fds[n], rfds, NULL, 0, &fd);
380 if (ret < 0)
381 goto warn;
382 if (ret == 0)
383 continue;
384 ret = -E_MAX_CLIENTS;
385 if (ss->max_clients > 0 && ss->num_clients >= ss->max_clients)
386 goto close_fd_and_warn;
387 ret = mark_fd_nonblocking(fd);
388 if (ret < 0)
389 goto close_fd_and_warn;
390 ret = acl_check_access(fd, &ss->acl, ss->default_deny);
391 if (ret < 0)
392 goto close_fd_and_warn;
393 ss->num_clients++;
394 sc = para_calloc(sizeof(*sc));
395 sc->fd = fd;
396 sc->name = para_strdup(remote_name(fd));
397 sc->cq = cq_new(MAX_CQ_BYTES);
398 para_list_add(&sc->node, &ss->client_list);
399 add_close_on_fork_list(fd);
400 PARA_INFO_LOG("accepted client #%d: %s (fd %d)\n", ss->num_clients,
401 sc->name, fd);
402 return sc;
403 close_fd_and_warn:
404 close(fd);
405 warn:
406 PARA_WARNING_LOG("%s\n", para_strerror(-ret));
407 }
408 return NULL;
409 }
410
411 /**
412 * Get the generic help text.
413 *
414 * \return A dynamically allocated string containing the help text for
415 * a paraslash sender.
416 */
417 char *generic_sender_help(void)
418 {
419 return make_message(
420 "usage: {on|off}\n"
421 "usage: {allow|deny} IP[/netmask]\n"
422 " where mask defaults to 32\n"
423 "example: allow 192.168.0.1/24\n"
424 );
425 }
426
427 static int parse_fec_parms(const char *arg, struct sender_command_data *scd)
428 {
429 int32_t val;
430 char *a = para_strdup(arg),
431 *b = strchr(a, ':'),
432 *c = strrchr(a, ':');
433 int ret = -E_COMMAND_SYNTAX;
434
435 if (!b || !c)
436 goto out;
437 *b = *c = '\0';
438
439 ret = para_atoi32(a, &val);
440 if (ret < 0)
441 goto out;
442
443 /* optional max_slice_bytes (0 means "use MTU") */
444 if (b == c) {
445 scd->max_slice_bytes = 0;
446 } else {
447 if (val < 0 || val > 65535)
448 goto fec_einval;
449 scd->max_slice_bytes = val;
450
451 ret = para_atoi32(b + 1, &val);
452 if (ret < 0)
453 goto out;
454 }
455
456 /* k = data_slices_per_group */
457 if (val < 0 || val > 255)
458 goto fec_einval;
459 scd->data_slices_per_group = val;
460
461 /* n = slices_per_group */
462 ret = para_atoi32(c + 1, &val);
463 if (ret < 0)
464 goto out;
465 if (val < 0 || val < scd->data_slices_per_group)
466 goto fec_einval;
467 scd->slices_per_group = val;
468 ret = 0;
469 out:
470 free(a);
471 return ret;
472 fec_einval:
473 ret = -ERRNO_TO_PARA_ERROR(EINVAL);
474 goto out;
475 }
476
477 /**
478 * Parse a FEC URL string.
479 *
480 * \param arg the URL string to parse.
481 * \param scd The structure containing host, port and the FEC parameters.
482 *
483 * \return Standard.
484 *
485 * A FEC URL consists of an ordinary URL string according to RFC 3986,
486 * optionally followed by a slash and the three FEC parameters slice_size,
487 * data_slices_per_group and slices_per_group. The three FEC parameters are
488 * separated by colons.
489 *
490 * \sa \ref parse_url().
491 */
492 int parse_fec_url(const char *arg, struct sender_command_data *scd)
493 {
494 char *a = para_strdup(arg), *p = strchr(a, '/');
495 int ret = 0;
496
497 /* default fec parameters */
498 scd->max_slice_bytes = 0;
499 scd->data_slices_per_group = 14;
500 scd->slices_per_group = 16;
501
502 if (p) {
503 *p = '\0';
504 ret = parse_fec_parms(p + 1, scd);
505 if (ret < 0)
506 goto out;
507 }
508 if (!parse_url(a, scd->host, sizeof(scd->host), &scd->port))
509 ret = -ERRNO_TO_PARA_ERROR(EINVAL);
510 out:
511 free(a);
512 return ret;
513 }