Merge branch 'refs/heads/t/clean_server_exit'
[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 port The tcp or dccp port to listen on.
109 * \param max_clients The maximal number of simultaneous connections.
110 * \param default_deny Whether a blacklist should be used for access control.
111 */
112 void init_sender_status(struct sender_status *ss,
113 const struct lls_opt_result *acl_opt_result, int port,
114 int max_clients, int default_deny)
115 {
116 int i;
117
118 ss->listen_fd = -1;
119 INIT_LIST_HEAD(&ss->client_list);
120 ss->port = port;
121
122 /* Initialize an access control list */
123 INIT_LIST_HEAD(&ss->acl);
124 for (i = 0; i < lls_opt_given(acl_opt_result); i++) {
125 const char *arg = lls_string_val(i, acl_opt_result);
126 char addr[16];
127 int mask;
128 if (!parse_cidr(arg, addr, sizeof(addr), &mask))
129 PARA_WARNING_LOG("ACL syntax error: %s, ignoring\n",
130 arg);
131 else
132 acl_add_entry(&ss->acl, addr, mask);
133 }
134 ss->num_clients = 0;
135 ss->max_clients = max_clients;
136 ss->default_deny = default_deny;
137 }
138
139 /**
140 * Return a string containing the current status of a sender.
141 *
142 * \param ss The sender.
143 * \param name Used for printing the header line.
144 *
145 * \return The string printed in the "si" command.
146 */
147 char *generic_sender_status(struct sender_status *ss, const char *name)
148 {
149 char *clnts = NULL, *ret;
150 struct sender_client *sc, *tmp_sc;
151
152 char *acl_contents = acl_get_contents(&ss->acl);
153 list_for_each_entry_safe(sc, tmp_sc, &ss->client_list, node) {
154 char *tmp = make_message("%s%s ", clnts? clnts : "", sc->name);
155 free(clnts);
156 clnts = tmp;
157 }
158 ret = make_message(
159 "status: %s\n"
160 "port: %s\n"
161 "number of connected clients: %d\n"
162 "maximal number of clients: %d%s\n"
163 "connected clients: %s\n"
164 "access %s list: %s\n",
165 (ss->listen_fd >= 0)? "on" : "off",
166 stringify_port(ss->port, strcmp(name, "http") ? "dccp" : "tcp"),
167 ss->num_clients,
168 ss->max_clients,
169 ss->max_clients > 0? "" : " (unlimited)",
170 clnts? clnts : "(none)",
171 ss->default_deny? "allow" : "deny",
172 acl_contents? acl_contents : "(empty)"
173 );
174 free(acl_contents);
175 free(clnts);
176 return ret;
177 }
178
179 /**
180 * Allow connections from the given range of IP addresses.
181 *
182 * \param scd Contains the IP and the netmask.
183 * \param ss The sender.
184 *
185 * \sa \ref generic_com_deny().
186 */
187 void generic_com_allow(struct sender_command_data *scd,
188 struct sender_status *ss)
189 {
190 acl_allow(scd->host, scd->netmask, &ss->acl, ss->default_deny);
191 }
192
193 /**
194 * Empty the access control list of a sender.
195 *
196 * \param acl The access control list of the sender.
197 *
198 * This is called from the ->shutdown methods of the http and the dccp sender.
199 */
200 void generic_acl_deplete(struct list_head *acl)
201 {
202 /*
203 * Since default_deny is false, the ACL is considered a blacklist. A
204 * netmask of zero matches any IP address, so this call empties the ACL.
205 */
206 acl_allow("0.0.0.0", 0 /* netmask */, acl, 0 /* default_deny */);
207 }
208
209 /**
210 * Deny connections from the given range of IP addresses.
211 *
212 * \param scd see \ref generic_com_allow().
213 * \param ss see \ref generic_com_allow().
214 *
215 * \sa \ref generic_com_allow().
216 */
217 void generic_com_deny(struct sender_command_data *scd,
218 struct sender_status *ss)
219 {
220 acl_deny(scd->host, scd->netmask, &ss->acl, ss->default_deny);
221 }
222
223 /**
224 * Activate a paraslash sender.
225 *
226 * \param ss The sender to activate.
227 * \param protocol layer4 type (IPPROTO_TCP or IPPROTO_DCCP).
228 *
229 * This opens a passive socket of given layer4 type, sets the resulting file
230 * descriptor to nonblocking mode and adds it to the close on fork list.
231 *
232 * Errors are logged but otherwise ignored.
233 */
234 void generic_com_on(struct sender_status *ss, unsigned protocol)
235 {
236 int fd, ret;
237
238 if (ss->listen_fd >= 0)
239 return;
240 ret = para_listen_simple(protocol, ss->port);
241 if (ret < 0) {
242 PARA_ERROR_LOG("could not listen on port %d: %s\n", ss->port,
243 para_strerror(-ret));
244 return;
245 }
246 fd = ret;
247 ret = mark_fd_nonblocking(fd);
248 if (ret < 0) {
249 PARA_ERROR_LOG("could not set %s socket fd for port %d to "
250 "nonblocking mode: %s\n",
251 protocol == IPPROTO_TCP? "TCP" : "DCCP", ss->port,
252 para_strerror(-ret));
253 close(fd);
254 return;
255 }
256 add_close_on_fork_list(fd);
257 ss->listen_fd = fd;
258 return;
259 }
260
261 /**
262 * Deactivate a paraslash sender.
263 *
264 * Shutdown all connected clients and stop listening on the TCP/DCCP socket.
265 *
266 * \param ss The sender to deactivate.
267 *
268 * \sa \ref del_close_on_fork_list(), \ref shutdown_clients().
269 */
270 void generic_com_off(struct sender_status *ss)
271 {
272 if (ss->listen_fd < 0)
273 return;
274 PARA_NOTICE_LOG("closing port %d\n", ss->port);
275 close(ss->listen_fd);
276 del_close_on_fork_list(ss->listen_fd);
277 shutdown_clients(ss);
278 ss->listen_fd = -1;
279 }
280
281 /**
282 * Accept a connection on the socket this server is listening on.
283 *
284 * \param ss The sender whose listening fd is ready for reading.
285 * \param rfds Passed to para_accept(),
286 *
287 * This calls para_accept() and performs the following actions on the resulting
288 * file descriptor fd:
289 *
290 * - Checks whether the maximal number of connections are exceeded.
291 * - Sets \a fd to nonblocking mode.
292 * - Checks the acl of the sender to find out whether connections
293 * are allowed from the IP of the connecting peer.
294 * - Increases the number of connections for this sender.
295 * - Creates and initializes a new chunk queue for queuing network
296 * packets that can not be sent immediately.
297 * - Allocates a new struct sender_client and fills in its \a fd, \a cq
298 * and \a name members.
299 * - Adds \a fd to the list of connected clients for this sender.
300 * - Adds \a fd to the list of file descriptors that should be closed
301 * in the child process when the server calls fork().
302 *
303 * \return A pointer to the allocated sender_client structure on success, \p
304 * NULL on errors.
305 *
306 * \sa \ref para_accept(), \ref mark_fd_nonblocking(), \ref acl_check_access(),
307 * \ref cq_new(), \ref add_close_on_fork_list().
308 */
309 struct sender_client *accept_sender_client(struct sender_status *ss, fd_set *rfds)
310 {
311 struct sender_client *sc;
312 int fd, ret;
313
314 if (ss->listen_fd < 0)
315 return NULL;
316 ret = para_accept(ss->listen_fd, rfds, NULL, 0, &fd);
317 if (ret < 0)
318 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
319 if (ret <= 0)
320 return NULL;
321 ret = -E_MAX_CLIENTS;
322 if (ss->max_clients > 0 && ss->num_clients >= ss->max_clients)
323 goto err_out;
324 ret = mark_fd_nonblocking(fd);
325 if (ret < 0)
326 goto err_out;
327 ret = acl_check_access(fd, &ss->acl, ss->default_deny);
328 if (ret < 0)
329 goto err_out;
330 ss->num_clients++;
331 sc = para_calloc(sizeof(*sc));
332 sc->fd = fd;
333 sc->name = para_strdup(remote_name(fd));
334 sc->cq = cq_new(MAX_CQ_BYTES);
335 para_list_add(&sc->node, &ss->client_list);
336 add_close_on_fork_list(fd);
337 PARA_INFO_LOG("accepted client #%d: %s (fd %d)\n", ss->num_clients,
338 sc->name, fd);
339 return sc;
340 err_out:
341 PARA_WARNING_LOG("%s\n", para_strerror(-ret));
342 close(fd);
343 return NULL;
344 }
345
346 /**
347 * Get the generic help text.
348 *
349 * \return A dynamically allocated string containing the help text for
350 * a paraslash sender.
351 */
352 char *generic_sender_help(void)
353 {
354 return make_message(
355 "usage: {on|off}\n"
356 "usage: {allow|deny} IP[/netmask]\n"
357 " where mask defaults to 32\n"
358 "example: allow 192.168.0.1/24\n"
359 );
360 }
361
362 static int parse_fec_parms(const char *arg, struct sender_command_data *scd)
363 {
364 int32_t val;
365 char *a = para_strdup(arg),
366 *b = strchr(a, ':'),
367 *c = strrchr(a, ':');
368 int ret = -E_COMMAND_SYNTAX;
369
370 if (!b || !c)
371 goto out;
372 *b = *c = '\0';
373
374 ret = para_atoi32(a, &val);
375 if (ret < 0)
376 goto out;
377
378 /* optional max_slice_bytes (0 means "use MTU") */
379 if (b == c) {
380 scd->max_slice_bytes = 0;
381 } else {
382 if (val < 0 || val > 65535)
383 goto fec_einval;
384 scd->max_slice_bytes = val;
385
386 ret = para_atoi32(b + 1, &val);
387 if (ret < 0)
388 goto out;
389 }
390
391 /* k = data_slices_per_group */
392 if (val < 0 || val > 255)
393 goto fec_einval;
394 scd->data_slices_per_group = val;
395
396 /* n = slices_per_group */
397 ret = para_atoi32(c + 1, &val);
398 if (ret < 0)
399 goto out;
400 if (val < 0 || val < scd->data_slices_per_group)
401 goto fec_einval;
402 scd->slices_per_group = val;
403 ret = 0;
404 out:
405 free(a);
406 return ret;
407 fec_einval:
408 ret = -ERRNO_TO_PARA_ERROR(EINVAL);
409 goto out;
410 }
411
412 /**
413 * Parse a FEC URL string.
414 *
415 * \param arg the URL string to parse.
416 * \param scd The structure containing host, port and the FEC parameters.
417 *
418 * \return Standard.
419 *
420 * A FEC URL consists of an ordinary URL string according to RFC 3986,
421 * optionally followed by a slash and the three FEC parameters slice_size,
422 * data_slices_per_group and slices_per_group. The three FEC parameters are
423 * separated by colons.
424 *
425 * \sa \ref parse_url().
426 */
427 int parse_fec_url(const char *arg, struct sender_command_data *scd)
428 {
429 char *a = para_strdup(arg), *p = strchr(a, '/');
430 int ret = 0;
431
432 /* default fec parameters */
433 scd->max_slice_bytes = 0;
434 scd->data_slices_per_group = 14;
435 scd->slices_per_group = 16;
436
437 if (p) {
438 *p = '\0';
439 ret = parse_fec_parms(p + 1, scd);
440 if (ret < 0)
441 goto out;
442 }
443 if (!parse_url(a, scd->host, sizeof(scd->host), &scd->port))
444 ret = -ERRNO_TO_PARA_ERROR(EINVAL);
445 out:
446 free(a);
447 return ret;
448 }