Make para_server use the generic scheduling code.
[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 * \param header_buf The audio file header.
165 * \param header_len The number of bytes of \a header_buf.
166 *
167 * On errors, the client is shut down. If only a part of the buffer could be
168 * written, the remainder is put into the chunk queue for that client.
169 */
170 void send_chunk(struct sender_client *sc, struct sender_status *ss,
171 size_t max_bytes_per_write, long unsigned current_chunk,
172 const char *buf, size_t len, const char *header_buf,
173 size_t header_len)
174 {
175 int ret;
176
177 if (!sc->header_sent && current_chunk) {
178 if (header_buf && header_len > 0) {
179 ret = queue_chunk_or_shutdown(sc, ss, header_buf, header_len);
180 if (ret < 0)
181 goto out;
182 }
183 sc->header_sent = 1;
184 }
185 ret = send_queued_chunks(sc, max_bytes_per_write);
186 if (ret < 0) {
187 shutdown_client(sc, ss);
188 goto out;
189 }
190 if (!len)
191 goto out;
192 if (!ret) { /* still data left in the queue */
193 ret = queue_chunk_or_shutdown(sc, ss, buf, len);
194 goto out;
195 }
196 ret = write_nonblock(sc->fd, buf, len, max_bytes_per_write);
197 if (ret < 0) {
198 shutdown_client(sc, ss);
199 goto out;
200 }
201 if (ret != len)
202 ret = queue_chunk_or_shutdown(sc, ss, buf + ret, len - ret);
203 out:
204 if (ret < 0)
205 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
206 }
207
208 /**
209 * Initialize a struct sender status.
210 *
211 * \param ss The struct to initialize.
212 * \param access_arg The array of access arguments given at the command line.
213 * \param num_access_args The number of elements in \a access_arg.
214 * \param port The tcp or dccp port to listen on.
215 * \param max_clients The maximal number of simultaneous connections.
216 * \param default_deny Whether a blacklist should be used for access control.
217 */
218 void init_sender_status(struct sender_status *ss, char **access_arg,
219 int num_access_args, int port, int max_clients, int default_deny)
220 {
221 ss->listen_fd = -1;
222 INIT_LIST_HEAD(&ss->client_list);
223 ss->port = port;
224 acl_init(&ss->acl, access_arg, num_access_args);
225 ss->num_clients = 0;
226 ss->max_clients = max_clients;
227 ss->default_deny = default_deny;
228 }
229
230 /**
231 * Return a string containing the current status of a sender.
232 *
233 * \param ss The sender.
234 * \param name Used for printing the header line.
235 *
236 * \return The string printed in the "si" command.
237 */
238 char *get_sender_info(struct sender_status *ss, char *name)
239 {
240 char *clnts = NULL, *ret;
241 struct sender_client *sc, *tmp_sc;
242
243 char *acl_contents = acl_get_contents(&ss->acl);
244 list_for_each_entry_safe(sc, tmp_sc, &ss->client_list, node) {
245 char *tmp = make_message("%s%s ", clnts? clnts : "", sc->name);
246 free(clnts);
247 clnts = tmp;
248 }
249 ret = make_message(
250 "%s sender:\n"
251 "\tstatus: %s\n"
252 "\tport: %d\n"
253 "\tnumber of connected clients: %d\n"
254 "\tmaximal number of clients: %d%s\n"
255 "\tconnected clients: %s\n"
256 "\taccess %s list: %s\n",
257 name,
258 (ss->listen_fd >= 0)? "on" : "off",
259 ss->port,
260 ss->num_clients,
261 ss->max_clients,
262 ss->max_clients > 0? "" : " (unlimited)",
263 clnts? clnts : "(none)",
264 ss->default_deny? "allow" : "deny",
265 acl_contents? acl_contents : "(empty)"
266 );
267 free(acl_contents);
268 free(clnts);
269 return ret;
270 }
271
272 /**
273 * Allow connections from the given range of IP addresses.
274 *
275 * \param scd Contains the IP and the netmask.
276 * \param ss The sender.
277 *
278 * \sa generic_com_deny().
279 */
280 void generic_com_allow(struct sender_command_data *scd,
281 struct sender_status *ss)
282 {
283 acl_allow(scd->addr, scd->netmask, &ss->acl, ss->default_deny);
284 }
285
286 /**
287 * Deny connections from the given range of IP addresses.
288 *
289 * \param scd see \ref generic_com_allow().
290 * \param ss see \ref generic_com_allow().
291 *
292 * \sa generic_com_allow().
293 */
294 void generic_com_deny(struct sender_command_data *scd,
295 struct sender_status *ss)
296 {
297 acl_deny(scd->addr, scd->netmask, &ss->acl, ss->default_deny);
298 }
299
300 /**
301 * Activate a paraslash sender.
302 *
303 * \param ss The sender to activate.
304 * \param protocol The symbolic name of the transport-layer protocol.
305 *
306 * \return Standard.
307 */
308 int generic_com_on(struct sender_status *ss, unsigned protocol)
309 {
310 int ret;
311
312 if (ss->listen_fd >= 0)
313 return 1;
314 ret = open_sender(protocol, ss->port);
315 if (ret < 0)
316 return ret;
317 ss->listen_fd = ret;
318 return 1;
319 }
320
321 /**
322 * Deactivate a paraslash sender.
323 *
324 * Shutdown all connected clients and stop listening on the TCP/DCCP socket.
325 *
326 * \param ss The sender to deactivate.
327 *
328 * \sa \ref del_close_on_fork_list(), shutdown_clients().
329 */
330 void generic_com_off(struct sender_status *ss)
331 {
332 if (ss->listen_fd < 0)
333 return;
334 PARA_NOTICE_LOG("closing port %d\n", ss->port);
335 close(ss->listen_fd);
336 del_close_on_fork_list(ss->listen_fd);
337 shutdown_clients(ss);
338 ss->listen_fd = -1;
339 }
340
341 /**
342 * Accept a connection on the socket this server is listening on.
343 *
344 * \param ss The sender whose listening fd is ready for reading.
345 *
346 * This must be called only if the socket fd of \a ss is ready for reading. It
347 * calls para_accept() to accept the connection and performs the following
348 * actions on the resulting file descriptor \a fd:
349 *
350 * - Checks whether the maximal number of connections are exceeded.
351 * - Sets \a fd to nonblocking mode.
352 * - Checks the acl of the sender to find out whether connections
353 * are allowed from the IP of the connecting peer.
354 * - Increases the number of connections for this sender.
355 * - Creates and initializes a new chunk queue for queuing network
356 * packets that can not be sent immediately.
357 * - Allocates a new struct sender_client and fills in its \a fd, \a cq
358 * and \a name members.
359 * - Adds \a fd to the list of connected clients for this sender.
360 * - Adds \a fd to the list of file descriptors that should be closed
361 * in the child process when the server calls fork().
362 *
363 * \return A pointer to the allocated sender_client structure on success, \p
364 * NULL on errors.
365 *
366 * \sa \ref para_accept(), \ref mark_fd_nonblocking(), \ref acl_check_access(),
367 * \ref cq_new(), \ref add_close_on_fork_list().
368 */
369 struct sender_client *accept_sender_client(struct sender_status *ss)
370 {
371 struct sender_client *sc;
372 int fd, ret = para_accept(ss->listen_fd, NULL, 0);
373 if (ret < 0) {
374 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
375 return NULL;
376 }
377 fd = ret;
378 ret = -E_MAX_CLIENTS;
379 if (ss->max_clients > 0 && ss->num_clients >= ss->max_clients)
380 goto err_out;
381 ret = mark_fd_nonblocking(fd);
382 if (ret < 0)
383 goto err_out;
384 ret = acl_check_access(fd, &ss->acl, ss->default_deny);
385 if (ret < 0)
386 goto err_out;
387 ss->num_clients++;
388 sc = para_calloc(sizeof(*sc));
389 sc->fd = fd;
390 sc->name = make_message("%s", remote_name(fd));
391 sc->cq = cq_new(MAX_CQ_BYTES);
392 para_list_add(&sc->node, &ss->client_list);
393 add_close_on_fork_list(fd);
394 PARA_INFO_LOG("accepted client #%d: %s (fd %d)\n", ss->num_clients,
395 sc->name, fd);
396 return sc;
397 err_out:
398 PARA_WARNING_LOG("%s\n", para_strerror(-ret));
399 close(fd);
400 return NULL;
401 }
402
403 /**
404 * Get the generic help text.
405 *
406 * \return A dynamically allocated string containing the help text for
407 * a paraslash sender.
408 */
409 char *generic_sender_help(void)
410 {
411 return make_message(
412 "usage: {on|off}\n"
413 "usage: {allow|deny} IP mask\n"
414 "example: allow 127.0.0.1 32\n"
415 );
416 }