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 resultig 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 connected client.
  58  *
  59  * \param sc The client to be shut down.
  60  *
  61  * Close the file descriptor given by \a sc, remove it from the close-on-fork
  62  * list, destroy the chunk queue of this client, delete the client from the
  63  * list of connected clients and free the sender_client struct.
  64  */
  65 void shutdown_client(struct sender_client *sc, struct sender_status *ss)
  66 {
  67         PARA_INFO_LOG("shutting down %s on fd %d\n", sc->name, sc->fd);
  68         free(sc->name);
  69         close(sc->fd);
  70         del_close_on_fork_list(sc->fd);
  71         cq_destroy(sc->cq);
  72         list_del(&sc->node);
  73         free(sc->private_data);
  74         free(sc);
  75         ss->num_clients--;
  76 }
  77
  78 void shutdown_clients(struct sender_status *ss)
  79 {
  80         struct sender_client *sc, *tmp;
  81         list_for_each_entry_safe(sc, tmp, &ss->client_list, node)
  82                 shutdown_client(sc, ss);
  83 }
  84
  85 /**
  86  * Write a buffer to a non-blocking file descriptor.
  87  *
  88  * \param fd The file descriptor.
  89  * \param buf the buffer to write.
  90  * \param len the number of bytes of \a buf.
  91  * \param max_bytes_per_write Do not write more than that many bytes at once.
  92  *
  93  * If \a max_bytes_per_write is non-zero, do not send more than that many bytes
  94  * per write().
  95  *
  96  * EAGAIN is not considered an error condition.  For example CCID3 has a
  97  * sending wait queue which fills up and is emptied asynchronously. The EAGAIN
  98  * case means that there is currently no space in the wait queue, but this can
  99  * change at any moment.
 100  *
 101  * \return Negative on errors, number of bytes written else.
 102  */
 103 static int write_nonblock(int fd, const char *buf, size_t len,
 104                 size_t max_bytes_per_write)
 105 {
 106         size_t written = 0;
 107         int ret = 0;
 108
 109         while (written < len) {
 110                 size_t num = len - written;
 111
 112                 if (max_bytes_per_write && max_bytes_per_write < num)
 113                         num = max_bytes_per_write;
 114                 ret = write(fd, buf + written, num);
 115                 if (ret < 0 && errno == EAGAIN)
 116                         return written;
 117                 if (ret < 0)
 118                         return -ERRNO_TO_PARA_ERROR(errno);
 119                 written += ret;
 120         }
 121         return written;
 122 }
 123
 124 static int queue_chunk_or_shutdown(struct sender_client *sc,
 125                 struct sender_status *ss, long unsigned chunk_num,
 126                 size_t sent)
 127 {
 128         int ret = cq_enqueue(sc->cq, chunk_num, sent);
 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                 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 max_bytes_per_write Split writes to chunks of at most that many bytes.
 160  * \param current_chunk The number of the chunk to write.
 161  * \param buf The data to write.
 162  * \param len The number of bytes of \a buf.
 163  *
 164  * On errors, the client is shut down. If only a part of the buffer could be
 165  * written, the remainder is put into the chunk queue for that client.
 166  */
 167 void send_chunk(struct sender_client *sc, struct sender_status *ss,
 168                 size_t max_bytes_per_write, long unsigned current_chunk,
 169                 const char *buf, size_t len)
 170 {
 171         int ret;
 172
 173         if (!sc->header_sent && current_chunk) {
 174                 size_t header_len;
 175                 char *header_buf = vss_get_header(&header_len);
 176                 if (header_buf && header_len > 0) {
 177                         ret = queue_chunk_or_shutdown(sc, ss, -1U, 0);
 178                         if (ret < 0)
 179                                 goto out;
 180                 }
 181                 sc->header_sent = 1;
 182         }
 183         ret = send_queued_chunks(sc, max_bytes_per_write);
 184         if (ret < 0) {
 185                 shutdown_client(sc, ss);
 186                 goto out;
 187         }
 188         if (!len)
 189                 goto out;
 190         if (!ret) { /* still data left in the queue */
 191                 ret = queue_chunk_or_shutdown(sc, ss, current_chunk, 0);
 192                 goto out;
 193         }
 194         ret = write_nonblock(sc->fd, buf, len, max_bytes_per_write);
 195         if (ret < 0) {
 196                 shutdown_client(sc, ss);
 197                 goto out;
 198         }
 199         if (ret != len)
 200                 ret = queue_chunk_or_shutdown(sc, ss, current_chunk, ret);
 201 out:
 202         if (ret < 0)
 203                 PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
 204 }
 205
 206 void init_sender_status(struct sender_status *ss, char **access_arg,
 207         int num_access_args, int port, int max_clients, int default_deny)
 208 {
 209         ss->listen_fd = -1;
 210         INIT_LIST_HEAD(&ss->client_list);
 211         ss->port = port;
 212         acl_init(&ss->acl, access_arg, num_access_args);
 213         ss->num_clients = 0;
 214         ss->max_clients = max_clients;
 215         ss->default_deny = default_deny;
 216 }
 217
 218 char *get_sender_info(struct sender_status *ss, char *name)
 219 {
 220         char *clnts = NULL, *ret;
 221         struct sender_client *sc, *tmp_sc;
 222
 223         char *acl_contents = acl_get_contents(&ss->acl);
 224         list_for_each_entry_safe(sc, tmp_sc, &ss->client_list, node) {
 225                 char *tmp = make_message("%s%s ", clnts? clnts : "", sc->name);
 226                 free(clnts);
 227                 clnts = tmp;
 228         }
 229         ret = make_message(
 230                 "%s sender:\n"
 231                 "\tstatus: %s\n"
 232                 "\tport: %d\n"
 233                 "\tnumber of connected clients: %d\n"
 234                 "\tmaximal number of clients: %d%s\n"
 235                 "\tconnected clients: %s\n"
 236                 "\taccess %s list: %s\n",
 237                 name,
 238                 (ss->listen_fd >= 0)? "on" : "off",
 239                 ss->port,
 240                 ss->num_clients,
 241                 ss->max_clients,
 242                 ss->max_clients > 0? "" : " (unlimited)",
 243                 clnts? clnts : "(none)",
 244                 ss->default_deny? "allow" : "deny",
 245                 acl_contents? acl_contents : "(empty)"
 246         );
 247         free(acl_contents);
 248         free(clnts);
 249         return ret;
 250 }
 251
 252 void generic_com_allow(struct sender_command_data *scd,
 253                 struct sender_status *ss)
 254 {
 255         acl_allow(scd->addr, scd->netmask, &ss->acl, ss->default_deny);
 256 }
 257
 258 void generic_com_deny(struct sender_command_data *scd,
 259                 struct sender_status *ss)
 260 {
 261         acl_deny(scd->addr, scd->netmask, &ss->acl, ss->default_deny);
 262 }
 263
 264 int generic_com_on(struct sender_status *ss, unsigned protocol)
 265 {
 266         int ret;
 267
 268         if (ss->listen_fd >= 0)
 269                 return 1;
 270         ret = open_sender(protocol, ss->port);
 271         if (ret < 0)
 272                 return ret;
 273         ss->listen_fd = ret;
 274         return 1;
 275 }
 276
 277 void generic_com_off(struct sender_status *ss)
 278 {
 279         if (ss->listen_fd < 0)
 280                 return;
 281         PARA_NOTICE_LOG("closing port %d\n", ss->port);
 282         close(ss->listen_fd);
 283         del_close_on_fork_list(ss->listen_fd);
 284         shutdown_clients(ss);
 285         ss->listen_fd = -1;
 286 }
 287
 288 struct sender_client *accept_sender_client(struct sender_status *ss)
 289 {
 290         struct sender_client *sc;
 291         int fd, ret = para_accept(ss->listen_fd, NULL, 0);
 292         if (ret < 0) {
 293                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 294                 return NULL;
 295         }
 296         fd = ret;
 297         ret = -E_MAX_CLIENTS;
 298         if (ss->max_clients > 0 && ss->num_clients >= ss->max_clients)
 299                 goto err_out;
 300         ret = mark_fd_nonblocking(fd);
 301         if (ret < 0)
 302                 goto err_out;
 303         ret = acl_check_access(fd, &ss->acl, ss->default_deny);
 304         if (ret < 0)
 305                 goto err_out;
 306         ss->num_clients++;
 307         sc = para_calloc(sizeof(*sc));
 308         sc->fd = fd;
 309         sc->name = make_message("%s", remote_name(fd));
 310         sc->cq = cq_new(MAX_CQ_BYTES);
 311         para_list_add(&sc->node, &ss->client_list);
 312         add_close_on_fork_list(fd);
 313         PARA_INFO_LOG("accepted client #%d: %s (fd %d)\n", ss->num_clients,
 314                 sc->name, fd);
 315         return sc;
 316 err_out:
 317         PARA_WARNING_LOG("%s\n", para_strerror(-ret));
 318         close(fd);
 319         return NULL;
 320 }
 321
 322 char *generic_sender_help(void)
 323 {
 324         return make_message(
 325                 "usage: {on|off}\n"
 326                 "usage: {allow|deny} IP mask\n"
 327                 "example: allow 127.0.0.1 32\n"
 328         );
 329 }