server: Convert com_mvatt() to lopsub.
[paraslash.git] / send_common.c
1 /*
2 * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file send_common.c Functions used by more than one paraslash sender. */
8
9 #include <netinet/in.h>
10 #include <sys/socket.h>
11 #include <regex.h>
12 #include <osl.h>
13 #include <arpa/inet.h>
14 #include <sys/un.h>
15 #include <netdb.h>
16 #include <lopsub.h>
17
18 #include "para.h"
19 #include "error.h"
20 #include "string.h"
21 #include "fd.h"
22 #include "net.h"
23 #include "list.h"
24 #include "afh.h"
25 #include "afs.h"
26 #include "server.h"
27 #include "acl.h"
28 #include "send.h"
29 #include "close_on_fork.h"
30 #include "chunk_queue.h"
31 #include "sched.h"
32 #include "vss.h"
33
34 /** Clients will be kicked if there are more than that many bytes pending. */
35 #define MAX_CQ_BYTES 40000
36
37 /**
38 * Open a passive socket of given layer4 type.
39 *
40 * Set the resulting file descriptor to nonblocking mode and add it to the list
41 * of fds that are being closed in the child process when the server calls
42 * fork().
43 *
44 * \param l4type The transport-layer protocol.
45 * \param port The port number.
46 *
47 * \return The listening fd on success, negative on errors.
48 */
49 static int open_sender(unsigned l4type, int port)
50 {
51 int fd, ret = para_listen_simple(l4type, port);
52
53 if (ret < 0)
54 return ret;
55 fd = ret;
56 ret = mark_fd_nonblocking(fd);
57 if (ret < 0) {
58 close(fd);
59 return ret;
60 }
61 add_close_on_fork_list(fd);
62 return fd;
63 }
64
65 /**
66 * Shut down a client connected to a paraslash sender.
67 *
68 * \param sc The client to shut down.
69 * \param ss The sender whose clients are to be shut down.
70 *
71 * Close the file descriptor given by \a sc, remove it from the close-on-fork
72 * list, destroy the chunk queue of this client, delete the client from the
73 * list of connected clients and free the sender_client struct.
74 *
75 * \sa shutdown_clients().
76 */
77 void shutdown_client(struct sender_client *sc, struct sender_status *ss)
78 {
79 PARA_INFO_LOG("shutting down %s on fd %d\n", sc->name, sc->fd);
80 free(sc->name);
81 close(sc->fd);
82 del_close_on_fork_list(sc->fd);
83 cq_destroy(sc->cq);
84 list_del(&sc->node);
85 free(sc->private_data);
86 free(sc);
87 ss->num_clients--;
88 }
89
90 /**
91 * Shut down all clients connected to a paraslash sender.
92 *
93 * \param ss The sender whose clients are to be shut down.
94 *
95 * This just loops over all connected clients and calls shutdown_client()
96 * for each client.
97 */
98 void shutdown_clients(struct sender_status *ss)
99 {
100 struct sender_client *sc, *tmp;
101 list_for_each_entry_safe(sc, tmp, &ss->client_list, node)
102 shutdown_client(sc, ss);
103 }
104
105 /**
106 * Try to empty the chunk queue for this fd.
107 *
108 * \param fd The file descriptor.
109 * \param cq The list of queued chunks.
110 *
111 * \return Negative on errors, zero if not everything was sent, one otherwise.
112 */
113 int send_queued_chunks(int fd, struct chunk_queue *cq)
114 {
115 struct queued_chunk *qc;
116 while ((qc = cq_peek(cq))) {
117 const char *buf;
118 size_t len;
119 int ret;
120
121 cq_get(qc, &buf, &len);
122 ret = xwrite(fd, buf, len);
123 if (ret < 0)
124 return ret;
125 cq_update(cq, ret);
126 if (ret != len)
127 return 0;
128 cq_dequeue(cq);
129 }
130 return 1;
131 }
132
133 /**
134 * Initialize a struct sender status.
135 *
136 * \param ss The struct to initialize.
137 * \param access_arg The array of access arguments given at the command line.
138 * \param num_access_args The number of elements in \a access_arg.
139 * \param port The tcp or dccp port to listen on.
140 * \param max_clients The maximal number of simultaneous connections.
141 * \param default_deny Whether a blacklist should be used for access control.
142 */
143 void init_sender_status(struct sender_status *ss, char **access_arg,
144 int num_access_args, int port, int max_clients, int default_deny)
145 {
146 ss->listen_fd = -1;
147 INIT_LIST_HEAD(&ss->client_list);
148 ss->port = port;
149 acl_init(&ss->acl, access_arg, num_access_args);
150 ss->num_clients = 0;
151 ss->max_clients = max_clients;
152 ss->default_deny = default_deny;
153 }
154
155 /**
156 * Return a string containing the current status of a sender.
157 *
158 * \param ss The sender.
159 * \param name Used for printing the header line.
160 *
161 * \return The string printed in the "si" command.
162 */
163 char *generic_sender_status(struct sender_status *ss, const char *name)
164 {
165 char *clnts = NULL, *ret;
166 struct sender_client *sc, *tmp_sc;
167
168 char *acl_contents = acl_get_contents(&ss->acl);
169 list_for_each_entry_safe(sc, tmp_sc, &ss->client_list, node) {
170 char *tmp = make_message("%s%s ", clnts? clnts : "", sc->name);
171 free(clnts);
172 clnts = tmp;
173 }
174 ret = make_message(
175 "status: %s\n"
176 "port: %s\n"
177 "number of connected clients: %d\n"
178 "maximal number of clients: %d%s\n"
179 "connected clients: %s\n"
180 "access %s list: %s\n",
181 (ss->listen_fd >= 0)? "on" : "off",
182 stringify_port(ss->port, strcmp(name, "http") ? "dccp" : "tcp"),
183 ss->num_clients,
184 ss->max_clients,
185 ss->max_clients > 0? "" : " (unlimited)",
186 clnts? clnts : "(none)",
187 ss->default_deny? "allow" : "deny",
188 acl_contents? acl_contents : "(empty)"
189 );
190 free(acl_contents);
191 free(clnts);
192 return ret;
193 }
194
195 /**
196 * Allow connections from the given range of IP addresses.
197 *
198 * \param scd Contains the IP and the netmask.
199 * \param ss The sender.
200 *
201 * \sa generic_com_deny().
202 */
203 void generic_com_allow(struct sender_command_data *scd,
204 struct sender_status *ss)
205 {
206 acl_allow(scd->host, scd->netmask, &ss->acl, ss->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 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 The symbolic name of the transport-layer protocol.
228 *
229 * \return Standard.
230 */
231 int generic_com_on(struct sender_status *ss, unsigned protocol)
232 {
233 int ret;
234
235 if (ss->listen_fd >= 0)
236 return 1;
237 ret = open_sender(protocol, ss->port);
238 if (ret < 0)
239 return ret;
240 ss->listen_fd = ret;
241 return 1;
242 }
243
244 /**
245 * Deactivate a paraslash sender.
246 *
247 * Shutdown all connected clients and stop listening on the TCP/DCCP socket.
248 *
249 * \param ss The sender to deactivate.
250 *
251 * \sa \ref del_close_on_fork_list(), shutdown_clients().
252 */
253 void generic_com_off(struct sender_status *ss)
254 {
255 if (ss->listen_fd < 0)
256 return;
257 PARA_NOTICE_LOG("closing port %d\n", ss->port);
258 close(ss->listen_fd);
259 del_close_on_fork_list(ss->listen_fd);
260 shutdown_clients(ss);
261 ss->listen_fd = -1;
262 }
263
264 /**
265 * Accept a connection on the socket this server is listening on.
266 *
267 * \param ss The sender whose listening fd is ready for reading.
268 * \param rfds Passed to para_accept(),
269 *
270 * This must be called only if the socket fd of \a ss is ready for reading. It
271 * calls para_accept() to accept the connection and performs the following
272 * actions on the resulting file descriptor \a fd:
273 *
274 * - Checks whether the maximal number of connections are exceeded.
275 * - Sets \a fd to nonblocking mode.
276 * - Checks the acl of the sender to find out whether connections
277 * are allowed from the IP of the connecting peer.
278 * - Increases the number of connections for this sender.
279 * - Creates and initializes a new chunk queue for queuing network
280 * packets that can not be sent immediately.
281 * - Allocates a new struct sender_client and fills in its \a fd, \a cq
282 * and \a name members.
283 * - Adds \a fd to the list of connected clients for this sender.
284 * - Adds \a fd to the list of file descriptors that should be closed
285 * in the child process when the server calls fork().
286 *
287 * \return A pointer to the allocated sender_client structure on success, \p
288 * NULL on errors.
289 *
290 * \sa \ref para_accept(), \ref mark_fd_nonblocking(), \ref acl_check_access(),
291 * \ref cq_new(), \ref add_close_on_fork_list().
292 */
293 struct sender_client *accept_sender_client(struct sender_status *ss, fd_set *rfds)
294 {
295 struct sender_client *sc;
296 int fd, ret;
297
298 if (ss->listen_fd < 0)
299 return NULL;
300 ret = para_accept(ss->listen_fd, rfds, NULL, 0, &fd);
301 if (ret < 0)
302 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
303 if (ret <= 0)
304 return NULL;
305 ret = -E_MAX_CLIENTS;
306 if (ss->max_clients > 0 && ss->num_clients >= ss->max_clients)
307 goto err_out;
308 ret = mark_fd_nonblocking(fd);
309 if (ret < 0)
310 goto err_out;
311 ret = acl_check_access(fd, &ss->acl, ss->default_deny);
312 if (ret < 0)
313 goto err_out;
314 ss->num_clients++;
315 sc = para_calloc(sizeof(*sc));
316 sc->fd = fd;
317 sc->name = para_strdup(remote_name(fd));
318 sc->cq = cq_new(MAX_CQ_BYTES);
319 para_list_add(&sc->node, &ss->client_list);
320 add_close_on_fork_list(fd);
321 PARA_INFO_LOG("accepted client #%d: %s (fd %d)\n", ss->num_clients,
322 sc->name, fd);
323 return sc;
324 err_out:
325 PARA_WARNING_LOG("%s\n", para_strerror(-ret));
326 close(fd);
327 return NULL;
328 }
329
330 /**
331 * Get the generic help text.
332 *
333 * \return A dynamically allocated string containing the help text for
334 * a paraslash sender.
335 */
336 char *generic_sender_help(void)
337 {
338 return make_message(
339 "usage: {on|off}\n"
340 "usage: {allow|deny} IP[/netmask]\n"
341 " where mask defaults to 32\n"
342 "example: allow 192.168.0.1/24\n"
343 );
344 }
345
346 static int parse_fec_parms(const char *arg, struct sender_command_data *scd)
347 {
348 int32_t val;
349 char *a = para_strdup(arg),
350 *b = strchr(a, ':'),
351 *c = strrchr(a, ':');
352 int ret = -E_COMMAND_SYNTAX;
353
354 if (!b || !c)
355 goto out;
356 *b = *c = '\0';
357
358 ret = para_atoi32(a, &val);
359 if (ret < 0)
360 goto out;
361
362 /* optional max_slice_bytes (0 means "use MTU") */
363 if (b == c) {
364 scd->max_slice_bytes = 0;
365 } else {
366 if (val < 0 || val > 65535)
367 goto fec_einval;
368 scd->max_slice_bytes = val;
369
370 ret = para_atoi32(b + 1, &val);
371 if (ret < 0)
372 goto out;
373 }
374
375 /* k = data_slices_per_group */
376 if (val < 0 || val > 255)
377 goto fec_einval;
378 scd->data_slices_per_group = val;
379
380 /* n = slices_per_group */
381 ret = para_atoi32(c + 1, &val);
382 if (ret < 0)
383 goto out;
384 if (val < 0 || val < scd->data_slices_per_group)
385 goto fec_einval;
386 scd->slices_per_group = val;
387 ret = 0;
388 out:
389 free(a);
390 return ret;
391 fec_einval:
392 ret = -ERRNO_TO_PARA_ERROR(EINVAL);
393 goto out;
394 }
395
396 /**
397 * Parse a FEC URL string.
398 *
399 * \param arg the URL string to parse.
400 * \param scd The structure containing host, port and the FEC parameters.
401 *
402 * \return Standard.
403 *
404 * A FEC URL consists of an ordinary URL string according to RFC 3986,
405 * optionally followed by a slash and the three FEC parameters slice_size,
406 * data_slices_per_group and slices_per_group. The three FEC parameters are
407 * separated by colons.
408 *
409 * \sa \ref parse_url().
410 */
411 int parse_fec_url(const char *arg, struct sender_command_data *scd)
412 {
413 char *a = para_strdup(arg), *p = strchr(a, '/');
414 int ret = 0;
415
416 /* default fec parameters */
417 scd->max_slice_bytes = 0;
418 scd->data_slices_per_group = 14;
419 scd->slices_per_group = 16;
420
421 if (p) {
422 *p = '\0';
423 ret = parse_fec_parms(p + 1, scd);
424 if (ret < 0)
425 goto out;
426 }
427 if (!parse_url(a, scd->host, sizeof(scd->host), &scd->port))
428 ret = -ERRNO_TO_PARA_ERROR(EINVAL);
429 out:
430 free(a);
431 return ret;
432 }