vss: Include map in the vss task struct.
[paraslash.git] / send_common.c
1 /*
2 * Copyright (C) 2005-2008 Andre Noll <maan@systemlinux.org>
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 <dirent.h>
10 #include "para.h"
11 #include "error.h"
12 #include "string.h"
13 #include "fd.h"
14 #include "net.h"
15 #include "list.h"
16 #include "afh.h"
17 #include "afs.h"
18 #include "server.h"
19 #include "acl.h"
20 #include "send.h"
21 #include "close_on_fork.h"
22 #include "chunk_queue.h"
23 #include "vss.h"
24
25 /** Clients will be kicked if there are more than that many bytes pending. */
26 #define MAX_CQ_BYTES 40000
27
28 /**
29 * Open a passive socket of given layer4 type.
30 *
31 * Set the resulting file descriptor to nonblocking mode and add it to the list
32 * of fds that are being closed in the child process when the server calls
33 * fork().
34 *
35 * \param l4type The transport-layer protocol.
36 * \param port The port number.
37 *
38 * \return The listening fd on success, negative on errors.
39 */
40 static int open_sender(unsigned l4type, int port)
41 {
42 int fd, ret = para_listen(AF_UNSPEC, l4type, port);
43
44 if (ret < 0)
45 return ret;
46 fd = ret;
47 ret = mark_fd_nonblocking(fd);
48 if (ret < 0) {
49 close(fd);
50 return ret;
51 }
52 add_close_on_fork_list(fd);
53 return fd;
54 }
55
56 /**
57 * Shut down a client connected to a paraslash sender.
58 *
59 * \param sc The client to shut down.
60 * \param ss The sender whose clients are to be shut down.
61 *
62 * Close the file descriptor given by \a sc, remove it from the close-on-fork
63 * list, destroy the chunk queue of this client, delete the client from the
64 * list of connected clients and free the sender_client struct.
65 */
66 void shutdown_client(struct sender_client *sc, struct sender_status *ss)
67 {
68 PARA_INFO_LOG("shutting down %s on fd %d\n", sc->name, sc->fd);
69 free(sc->name);
70 close(sc->fd);
71 del_close_on_fork_list(sc->fd);
72 cq_destroy(sc->cq);
73 list_del(&sc->node);
74 free(sc->private_data);
75 free(sc);
76 ss->num_clients--;
77 }
78
79 void shutdown_clients(struct sender_status *ss)
80 {
81 struct sender_client *sc, *tmp;
82 list_for_each_entry_safe(sc, tmp, &ss->client_list, node)
83 shutdown_client(sc, ss);
84 }
85
86 /**
87 * Write a buffer to a non-blocking file descriptor.
88 *
89 * \param fd The file descriptor.
90 * \param buf the buffer to write.
91 * \param len the number of bytes of \a buf.
92 * \param max_bytes_per_write Do not write more than that many bytes at once.
93 *
94 * If \a max_bytes_per_write is non-zero, do not send more than that many bytes
95 * per write().
96 *
97 * EAGAIN is not considered an error condition. For example CCID3 has a
98 * sending wait queue which fills up and is emptied asynchronously. The EAGAIN
99 * case means that there is currently no space in the wait queue, but this can
100 * change at any moment.
101 *
102 * \return Negative on errors, number of bytes written else.
103 */
104 static int write_nonblock(int fd, const char *buf, size_t len,
105 size_t max_bytes_per_write)
106 {
107 size_t written = 0;
108 int ret = 0;
109
110 while (written < len) {
111 size_t num = len - written;
112
113 if (max_bytes_per_write && max_bytes_per_write < num)
114 num = max_bytes_per_write;
115 ret = write(fd, buf + written, num);
116 if (ret < 0 && errno == EAGAIN)
117 return written;
118 if (ret < 0)
119 return -ERRNO_TO_PARA_ERROR(errno);
120 written += ret;
121 }
122 return written;
123 }
124
125 static int queue_chunk_or_shutdown(struct sender_client *sc,
126 struct sender_status *ss, const char *buf, size_t num_bytes)
127 {
128 int ret = cq_enqueue(sc->cq, buf, num_bytes);
129 if (ret < 0)
130 shutdown_client(sc, ss);
131 return ret;
132 }
133
134 /* return: negative on errors, zero if not everything was sent, one otherwise */
135 static int send_queued_chunks(struct sender_client *sc,
136 size_t max_bytes_per_write)
137 {
138 struct queued_chunk *qc;
139 while ((qc = cq_peek(sc->cq))) {
140 const char *buf;
141 size_t len;
142 int ret;
143 cq_get(qc, &buf, &len);
144 ret = write_nonblock(sc->fd, buf, len, max_bytes_per_write);
145 if (ret < 0)
146 return ret;
147 cq_update(sc->cq, ret);
148 if (ret != len)
149 return 0;
150 cq_dequeue(sc->cq);
151 }
152 return 1;
153 }
154
155 /**
156 * Send one chunk of audio data to a connected client.
157 *
158 * \param sc The client.
159 * \param ss The sender.
160 * \param max_bytes_per_write Split writes to chunks of at most that many bytes.
161 * \param current_chunk The number of the chunk to write.
162 * \param buf The data to write.
163 * \param len The number of bytes of \a buf.
164 *
165 * On errors, the client is shut down. If only a part of the buffer could be
166 * written, the remainder is put into the chunk queue for that client.
167 */
168 void send_chunk(struct sender_client *sc, struct sender_status *ss,
169 size_t max_bytes_per_write, long unsigned current_chunk,
170 const char *buf, size_t len)
171 {
172 int ret;
173
174 if (!sc->header_sent && current_chunk) {
175 size_t header_len;
176 char *header_buf;
177
178 vss_get_header(&header_buf, &header_len);
179 if (header_buf && header_len > 0) {
180 ret = queue_chunk_or_shutdown(sc, ss, header_buf, header_len);
181 if (ret < 0)
182 goto out;
183 }
184 sc->header_sent = 1;
185 }
186 ret = send_queued_chunks(sc, max_bytes_per_write);
187 if (ret < 0) {
188 shutdown_client(sc, ss);
189 goto out;
190 }
191 if (!len)
192 goto out;
193 if (!ret) { /* still data left in the queue */
194 ret = queue_chunk_or_shutdown(sc, ss, buf, len);
195 goto out;
196 }
197 ret = write_nonblock(sc->fd, buf, len, max_bytes_per_write);
198 if (ret < 0) {
199 shutdown_client(sc, ss);
200 goto out;
201 }
202 if (ret != len)
203 ret = queue_chunk_or_shutdown(sc, ss, buf + ret, len - ret);
204 out:
205 if (ret < 0)
206 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
207 }
208
209 /**
210 * Initialize a struct sender status.
211 *
212 * \param ss The struct to initialize.
213 * \param access_arg The array of access arguments given at the command line.
214 * \param num_access_args The number of elements in \a access_arg.
215 * \param port The tcp or dccp port to listen on.
216 * \param max_clients The maximal number of simultaneous connections.
217 * \param default_deny Whether a blacklist should be used for access control.
218 */
219 void init_sender_status(struct sender_status *ss, char **access_arg,
220 int num_access_args, int port, int max_clients, int default_deny)
221 {
222 ss->listen_fd = -1;
223 INIT_LIST_HEAD(&ss->client_list);
224 ss->port = port;
225 acl_init(&ss->acl, access_arg, num_access_args);
226 ss->num_clients = 0;
227 ss->max_clients = max_clients;
228 ss->default_deny = default_deny;
229 }
230
231 /**
232 * Return a string containing the current status of a sender.
233 *
234 * \param ss The sender.
235 * \param name Used for printing the header line.
236 *
237 * \return The string printed in the "si" command.
238 */
239 char *get_sender_info(struct sender_status *ss, char *name)
240 {
241 char *clnts = NULL, *ret;
242 struct sender_client *sc, *tmp_sc;
243
244 char *acl_contents = acl_get_contents(&ss->acl);
245 list_for_each_entry_safe(sc, tmp_sc, &ss->client_list, node) {
246 char *tmp = make_message("%s%s ", clnts? clnts : "", sc->name);
247 free(clnts);
248 clnts = tmp;
249 }
250 ret = make_message(
251 "%s sender:\n"
252 "\tstatus: %s\n"
253 "\tport: %d\n"
254 "\tnumber of connected clients: %d\n"
255 "\tmaximal number of clients: %d%s\n"
256 "\tconnected clients: %s\n"
257 "\taccess %s list: %s\n",
258 name,
259 (ss->listen_fd >= 0)? "on" : "off",
260 ss->port,
261 ss->num_clients,
262 ss->max_clients,
263 ss->max_clients > 0? "" : " (unlimited)",
264 clnts? clnts : "(none)",
265 ss->default_deny? "allow" : "deny",
266 acl_contents? acl_contents : "(empty)"
267 );
268 free(acl_contents);
269 free(clnts);
270 return ret;
271 }
272
273 /**
274 * Allow connections from the given range of IP addresses.
275 *
276 * \param scd Contains the IP and the netmask.
277 * \param ss The sender.
278 *
279 * \sa generic_com_deny().
280 */
281 void generic_com_allow(struct sender_command_data *scd,
282 struct sender_status *ss)
283 {
284 acl_allow(scd->addr, scd->netmask, &ss->acl, ss->default_deny);
285 }
286
287 /**
288 * Deny connections from the given range of IP addresses.
289 *
290 * \param scd see \ref generic_com_allow().
291 * \param ss see \ref generic_com_allow().
292 *
293 * \sa generic_com_allow().
294 */
295 void generic_com_deny(struct sender_command_data *scd,
296 struct sender_status *ss)
297 {
298 acl_deny(scd->addr, scd->netmask, &ss->acl, ss->default_deny);
299 }
300
301 /**
302 * Activate a paraslash sender.
303 *
304 * \param ss The sender to activate.
305 * \param protocol The symbolic name of the transport-layer protocol.
306 *
307 * \return Standard.
308 */
309 int generic_com_on(struct sender_status *ss, unsigned protocol)
310 {
311 int ret;
312
313 if (ss->listen_fd >= 0)
314 return 1;
315 ret = open_sender(protocol, ss->port);
316 if (ret < 0)
317 return ret;
318 ss->listen_fd = ret;
319 return 1;
320 }
321
322 /**
323 * Deactivate a paraslash sender.
324 *
325 * Shutdown all connected clients and stop listening on the TCP/DCCP socket.
326 *
327 * \param ss The sender to deactivate.
328 *
329 * \sa \ref del_close_on_fork_list(), shutdown_clients().
330 */
331 void generic_com_off(struct sender_status *ss)
332 {
333 if (ss->listen_fd < 0)
334 return;
335 PARA_NOTICE_LOG("closing port %d\n", ss->port);
336 close(ss->listen_fd);
337 del_close_on_fork_list(ss->listen_fd);
338 shutdown_clients(ss);
339 ss->listen_fd = -1;
340 }
341
342 /**
343 * Accept a connection on the socket this server is listening on.
344 *
345 * \param ss The sender whose listening fd is ready for reading.
346 *
347 * This must be called only if the socket fd of \a ss is ready for reading. It
348 * calls para_accept() to accept the connection and performs the following
349 * actions on the resulting file descriptor \a fd:
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)
371 {
372 struct sender_client *sc;
373 int fd, ret = para_accept(ss->listen_fd, NULL, 0);
374 if (ret < 0) {
375 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
376 return NULL;
377 }
378 fd = ret;
379 ret = -E_MAX_CLIENTS;
380 if (ss->max_clients > 0 && ss->num_clients >= ss->max_clients)
381 goto err_out;
382 ret = mark_fd_nonblocking(fd);
383 if (ret < 0)
384 goto err_out;
385 ret = acl_check_access(fd, &ss->acl, ss->default_deny);
386 if (ret < 0)
387 goto err_out;
388 ss->num_clients++;
389 sc = para_calloc(sizeof(*sc));
390 sc->fd = fd;
391 sc->name = make_message("%s", remote_name(fd));
392 sc->cq = cq_new(MAX_CQ_BYTES);
393 para_list_add(&sc->node, &ss->client_list);
394 add_close_on_fork_list(fd);
395 PARA_INFO_LOG("accepted client #%d: %s (fd %d)\n", ss->num_clients,
396 sc->name, fd);
397 return sc;
398 err_out:
399 PARA_WARNING_LOG("%s\n", para_strerror(-ret));
400 close(fd);
401 return NULL;
402 }
403
404 /**
405 * Get the generic help text.
406 *
407 * \return A dynamically allocated string containing the help text for
408 * a paraslash sender.
409 */
410 char *generic_sender_help(void)
411 {
412 return make_message(
413 "usage: {on|off}\n"
414 "usage: {allow|deny} IP mask\n"
415 "example: allow 127.0.0.1 32\n"
416 );
417 }