Merge commit 'meins/master'
[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 * \sa shutdown_clients().
67 */
68 void shutdown_client(struct sender_client *sc, struct sender_status *ss)
69 {
70 PARA_INFO_LOG("shutting down %s on fd %d\n", sc->name, sc->fd);
71 free(sc->name);
72 close(sc->fd);
73 del_close_on_fork_list(sc->fd);
74 cq_destroy(sc->cq);
75 list_del(&sc->node);
76 free(sc->private_data);
77 free(sc);
78 ss->num_clients--;
79 }
80
81 /**
82 * Shut down all clients connected to a paraslash sender.
83 *
84 * \param ss The sender whose clients are to be shut down.
85 *
86 * This just loops over all connected clients and calls shutdown_client()
87 * for each client.
88 */
89 void shutdown_clients(struct sender_status *ss)
90 {
91 struct sender_client *sc, *tmp;
92 list_for_each_entry_safe(sc, tmp, &ss->client_list, node)
93 shutdown_client(sc, ss);
94 }
95
96 /**
97 * Write a buffer to a non-blocking file descriptor.
98 *
99 * \param fd The file descriptor.
100 * \param buf the buffer to write.
101 * \param len the number of bytes of \a buf.
102 * \param max_bytes_per_write Do not write more than that many bytes at once.
103 *
104 * If \a max_bytes_per_write is non-zero, do not send more than that many bytes
105 * per write().
106 *
107 * EAGAIN is not considered an error condition. For example CCID3 has a
108 * sending wait queue which fills up and is emptied asynchronously. The EAGAIN
109 * case means that there is currently no space in the wait queue, but this can
110 * change at any moment.
111 *
112 * \return Negative on errors, number of bytes written else.
113 */
114 static int write_nonblock(int fd, const char *buf, size_t len,
115 size_t max_bytes_per_write)
116 {
117 size_t written = 0;
118 int ret = 0;
119
120 while (written < len) {
121 size_t num = len - written;
122
123 if (max_bytes_per_write && max_bytes_per_write < num)
124 num = max_bytes_per_write;
125 ret = write(fd, buf + written, num);
126 if (ret < 0 && errno == EAGAIN)
127 return written;
128 if (ret < 0)
129 return -ERRNO_TO_PARA_ERROR(errno);
130 written += ret;
131 }
132 return written;
133 }
134
135 static int queue_chunk_or_shutdown(struct sender_client *sc,
136 struct sender_status *ss, const char *buf, size_t num_bytes)
137 {
138 int ret = cq_enqueue(sc->cq, buf, num_bytes);
139 if (ret < 0)
140 shutdown_client(sc, ss);
141 return ret;
142 }
143
144 /* return: negative on errors, zero if not everything was sent, one otherwise */
145 static int send_queued_chunks(struct sender_client *sc,
146 size_t max_bytes_per_write)
147 {
148 struct queued_chunk *qc;
149 while ((qc = cq_peek(sc->cq))) {
150 const char *buf;
151 size_t len;
152 int ret;
153 cq_get(qc, &buf, &len);
154 ret = write_nonblock(sc->fd, buf, len, max_bytes_per_write);
155 if (ret < 0)
156 return ret;
157 cq_update(sc->cq, ret);
158 if (ret != len)
159 return 0;
160 cq_dequeue(sc->cq);
161 }
162 return 1;
163 }
164
165 /**
166 * Send one chunk of audio data to a connected client.
167 *
168 * \param sc The client.
169 * \param ss The sender.
170 * \param max_bytes_per_write Split writes to chunks of at most that many bytes.
171 * \param current_chunk The number of the chunk to write.
172 * \param buf The data to write.
173 * \param len The number of bytes of \a buf.
174 * \param header_buf The audio file header.
175 * \param header_len The number of bytes of \a header_buf.
176 *
177 * On errors, the client is shut down. If only a part of the buffer could be
178 * written, the remainder is put into the chunk queue for that client.
179 */
180 void send_chunk(struct sender_client *sc, struct sender_status *ss,
181 size_t max_bytes_per_write, long unsigned current_chunk,
182 const char *buf, size_t len, const char *header_buf,
183 size_t header_len)
184 {
185 int ret;
186
187 if (!sc->header_sent && current_chunk) {
188 if (header_buf && header_len > 0) {
189 ret = queue_chunk_or_shutdown(sc, ss, header_buf, header_len);
190 if (ret < 0)
191 goto out;
192 }
193 sc->header_sent = 1;
194 }
195 ret = send_queued_chunks(sc, max_bytes_per_write);
196 if (ret < 0) {
197 shutdown_client(sc, ss);
198 goto out;
199 }
200 if (!len)
201 goto out;
202 if (!ret) { /* still data left in the queue */
203 ret = queue_chunk_or_shutdown(sc, ss, buf, len);
204 goto out;
205 }
206 ret = write_nonblock(sc->fd, buf, len, max_bytes_per_write);
207 if (ret < 0) {
208 shutdown_client(sc, ss);
209 goto out;
210 }
211 if (ret != len)
212 ret = queue_chunk_or_shutdown(sc, ss, buf + ret, len - ret);
213 out:
214 if (ret < 0)
215 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
216 }
217
218 /**
219 * Initialize a struct sender status.
220 *
221 * \param ss The struct to initialize.
222 * \param access_arg The array of access arguments given at the command line.
223 * \param num_access_args The number of elements in \a access_arg.
224 * \param port The tcp or dccp port to listen on.
225 * \param max_clients The maximal number of simultaneous connections.
226 * \param default_deny Whether a blacklist should be used for access control.
227 */
228 void init_sender_status(struct sender_status *ss, char **access_arg,
229 int num_access_args, int port, int max_clients, int default_deny)
230 {
231 ss->listen_fd = -1;
232 INIT_LIST_HEAD(&ss->client_list);
233 ss->port = port;
234 acl_init(&ss->acl, access_arg, num_access_args);
235 ss->num_clients = 0;
236 ss->max_clients = max_clients;
237 ss->default_deny = default_deny;
238 }
239
240 /**
241 * Return a string containing the current status of a sender.
242 *
243 * \param ss The sender.
244 * \param name Used for printing the header line.
245 *
246 * \return The string printed in the "si" command.
247 */
248 char *get_sender_info(struct sender_status *ss, char *name)
249 {
250 char *clnts = NULL, *ret;
251 struct sender_client *sc, *tmp_sc;
252
253 char *acl_contents = acl_get_contents(&ss->acl);
254 list_for_each_entry_safe(sc, tmp_sc, &ss->client_list, node) {
255 char *tmp = make_message("%s%s ", clnts? clnts : "", sc->name);
256 free(clnts);
257 clnts = tmp;
258 }
259 ret = make_message(
260 "%s sender:\n"
261 "\tstatus: %s\n"
262 "\tport: %d\n"
263 "\tnumber of connected clients: %d\n"
264 "\tmaximal number of clients: %d%s\n"
265 "\tconnected clients: %s\n"
266 "\taccess %s list: %s\n",
267 name,
268 (ss->listen_fd >= 0)? "on" : "off",
269 ss->port,
270 ss->num_clients,
271 ss->max_clients,
272 ss->max_clients > 0? "" : " (unlimited)",
273 clnts? clnts : "(none)",
274 ss->default_deny? "allow" : "deny",
275 acl_contents? acl_contents : "(empty)"
276 );
277 free(acl_contents);
278 free(clnts);
279 return ret;
280 }
281
282 /**
283 * Allow connections from the given range of IP addresses.
284 *
285 * \param scd Contains the IP and the netmask.
286 * \param ss The sender.
287 *
288 * \sa generic_com_deny().
289 */
290 void generic_com_allow(struct sender_command_data *scd,
291 struct sender_status *ss)
292 {
293 acl_allow(scd->addr, scd->netmask, &ss->acl, ss->default_deny);
294 }
295
296 /**
297 * Deny connections from the given range of IP addresses.
298 *
299 * \param scd see \ref generic_com_allow().
300 * \param ss see \ref generic_com_allow().
301 *
302 * \sa generic_com_allow().
303 */
304 void generic_com_deny(struct sender_command_data *scd,
305 struct sender_status *ss)
306 {
307 acl_deny(scd->addr, scd->netmask, &ss->acl, ss->default_deny);
308 }
309
310 /**
311 * Activate a paraslash sender.
312 *
313 * \param ss The sender to activate.
314 * \param protocol The symbolic name of the transport-layer protocol.
315 *
316 * \return Standard.
317 */
318 int generic_com_on(struct sender_status *ss, unsigned protocol)
319 {
320 int ret;
321
322 if (ss->listen_fd >= 0)
323 return 1;
324 ret = open_sender(protocol, ss->port);
325 if (ret < 0)
326 return ret;
327 ss->listen_fd = ret;
328 return 1;
329 }
330
331 /**
332 * Deactivate a paraslash sender.
333 *
334 * Shutdown all connected clients and stop listening on the TCP/DCCP socket.
335 *
336 * \param ss The sender to deactivate.
337 *
338 * \sa \ref del_close_on_fork_list(), shutdown_clients().
339 */
340 void generic_com_off(struct sender_status *ss)
341 {
342 if (ss->listen_fd < 0)
343 return;
344 PARA_NOTICE_LOG("closing port %d\n", ss->port);
345 close(ss->listen_fd);
346 del_close_on_fork_list(ss->listen_fd);
347 shutdown_clients(ss);
348 ss->listen_fd = -1;
349 }
350
351 /**
352 * Accept a connection on the socket this server is listening on.
353 *
354 * \param ss The sender whose listening fd is ready for reading.
355 *
356 * This must be called only if the socket fd of \a ss is ready for reading. It
357 * calls para_accept() to accept the connection and performs the following
358 * actions on the resulting file descriptor \a fd:
359 *
360 * - Checks whether the maximal number of connections are exceeded.
361 * - Sets \a fd to nonblocking mode.
362 * - Checks the acl of the sender to find out whether connections
363 * are allowed from the IP of the connecting peer.
364 * - Increases the number of connections for this sender.
365 * - Creates and initializes a new chunk queue for queuing network
366 * packets that can not be sent immediately.
367 * - Allocates a new struct sender_client and fills in its \a fd, \a cq
368 * and \a name members.
369 * - Adds \a fd to the list of connected clients for this sender.
370 * - Adds \a fd to the list of file descriptors that should be closed
371 * in the child process when the server calls fork().
372 *
373 * \return A pointer to the allocated sender_client structure on success, \p
374 * NULL on errors.
375 *
376 * \sa \ref para_accept(), \ref mark_fd_nonblocking(), \ref acl_check_access(),
377 * \ref cq_new(), \ref add_close_on_fork_list().
378 */
379 struct sender_client *accept_sender_client(struct sender_status *ss)
380 {
381 struct sender_client *sc;
382 int fd, ret = para_accept(ss->listen_fd, NULL, 0);
383 if (ret < 0) {
384 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
385 return NULL;
386 }
387 fd = ret;
388 ret = -E_MAX_CLIENTS;
389 if (ss->max_clients > 0 && ss->num_clients >= ss->max_clients)
390 goto err_out;
391 ret = mark_fd_nonblocking(fd);
392 if (ret < 0)
393 goto err_out;
394 ret = acl_check_access(fd, &ss->acl, ss->default_deny);
395 if (ret < 0)
396 goto err_out;
397 ss->num_clients++;
398 sc = para_calloc(sizeof(*sc));
399 sc->fd = fd;
400 sc->name = make_message("%s", remote_name(fd));
401 sc->cq = cq_new(MAX_CQ_BYTES);
402 para_list_add(&sc->node, &ss->client_list);
403 add_close_on_fork_list(fd);
404 PARA_INFO_LOG("accepted client #%d: %s (fd %d)\n", ss->num_clients,
405 sc->name, fd);
406 return sc;
407 err_out:
408 PARA_WARNING_LOG("%s\n", para_strerror(-ret));
409 close(fd);
410 return NULL;
411 }
412
413 /**
414 * Get the generic help text.
415 *
416 * \return A dynamically allocated string containing the help text for
417 * a paraslash sender.
418 */
419 char *generic_sender_help(void)
420 {
421 return make_message(
422 "usage: {on|off}\n"
423 "usage: {allow|deny} IP mask\n"
424 "example: allow 127.0.0.1 32\n"
425 );
426 }