dccp_send.c

   1 /*
   2  * Copyright (C) 2006-2008 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file dccp_send.c paraslash's dccp sender */
   8
   9 /*
  10  * based on server.c of dccp-cs-0.01.tar.bz2,
  11  * (C) 2005 Ian McDonald <imcdnzl@gmail.com>
  12  */
  13
  14 #include <sys/types.h>
  15 #include <dirent.h>
  16
  17 #include "para.h"
  18 #include "error.h"
  19 #include "string.h"
  20 #include "afh.h"
  21 #include "afs.h"
  22 #include "server.h"
  23 #include "net.h"
  24 #include "list.h"
  25 #include "vss.h"
  26 #include "send.h"
  27 #include "fd.h"
  28 #include "close_on_fork.h"
  29 #include "chunk_queue.h"
  30 #include "server.cmdline.h"
  31
  32 /** the list of connected clients **/
  33 static struct list_head clients;
  34 static int listen_fd = -1;
  35 static struct sender *self;
  36
  37 /** Maximal number of bytes in a chunk queue. */
  38 #define DCCP_MAX_PENDING_BYTES 40000
  39
  40 /** describes one connected client */
  41 struct dccp_client {
  42         /** the dccp socket */
  43         int fd;
  44         /** The socket `name' of the client. */
  45         char *name;
  46         /** the position of this client in the client list */
  47         struct list_head node;
  48         /** non-zero if audio file header has been sent */
  49         int header_sent;
  50         /** The list of pending chunks for this client. */
  51         struct chunk_queue *cq;
  52 };
  53
  54 static void dccp_pre_select( int *max_fileno, fd_set *rfds,
  55                 __a_unused fd_set *wfds)
  56 {
  57         if (listen_fd < 0)
  58                 return;
  59         FD_SET(listen_fd, rfds);
  60         *max_fileno = PARA_MAX(*max_fileno, listen_fd);
  61 }
  62
  63 static void dccp_post_select(fd_set *rfds, __a_unused fd_set *wfds)
  64 {
  65         struct dccp_client *dc;
  66         int ret, fd;
  67
  68         if (listen_fd < 0 || !FD_ISSET(listen_fd, rfds))
  69                 return;
  70         ret = para_accept(listen_fd, NULL, 0);
  71         if (ret < 0) {
  72                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
  73                 return;
  74         }
  75         fd = ret;
  76         /*
  77          * Bypass unused CCID paths: the sender does not receive application data
  78          * from the client; by shutting down this unused communication path we can
  79          * reduce processing costs a bit. See analogous comment in dccp_recv.c.
  80          */
  81         if (shutdown(fd, SHUT_RD) < 0) {
  82                 PARA_ERROR_LOG("shutdown(SHUT_RD): %s\n", strerror(errno));
  83                 goto err;
  84         }
  85         ret = mark_fd_nonblocking(fd);
  86         if (ret < 0) {
  87                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
  88                 goto err;
  89         }
  90         dc = para_calloc(sizeof(struct dccp_client));
  91         dc->fd = fd;
  92         dc->name = make_message("%s", remote_name(dc->fd));
  93         PARA_NOTICE_LOG("connection from %s\n", dc->name);
  94         para_list_add(&dc->node, &clients);
  95         add_close_on_fork_list(dc->fd);
  96         dc->cq = cq_new(DCCP_MAX_PENDING_BYTES);
  97         return;
  98 err:
  99         close(fd);
 100 }
 101
 102 static int dccp_open(void)
 103 {
 104         int ret = para_listen(AF_UNSPEC, IPPROTO_DCCP, conf.dccp_port_arg);
 105
 106         if (ret < 0)
 107                 return ret;
 108         listen_fd = ret;
 109         ret = mark_fd_nonblocking(listen_fd);
 110         if (ret < 0) {
 111                 PARA_EMERG_LOG("%s\n", para_strerror(-ret));
 112                 exit(EXIT_FAILURE);
 113         }
 114         add_close_on_fork_list(listen_fd);
 115         return 1;
 116 }
 117
 118 static void dccp_shutdown_client(struct dccp_client *dc)
 119 {
 120         PARA_DEBUG_LOG("shutting down %s (fd %d)\n", dc->name, dc->fd);
 121         free(dc->name);
 122         close(dc->fd);
 123         del_close_on_fork_list(dc->fd);
 124         cq_destroy(dc->cq);
 125         list_del(&dc->node);
 126         free(dc);
 127 }
 128
 129 /*
 130  * ret: Negative on errors, zero if nothing was written and write returned
 131  * EAGAIN, number of bytes written else.
 132  */
 133 static int dccp_write(int fd, const char *buf, size_t len)
 134 {
 135         size_t written = 0;
 136         int ret = 0;
 137
 138         while (written < len) {
 139                 ret = write(fd, buf + written, PARA_MIN(1024, len - written));
 140                 /*
 141                  * Error handling: CCID3 has a sending wait queue which fills up and is
 142                  * emptied asynchronously. The EAGAIN case means that there is currently
 143                  * no space in the wait queue, but this can change at any moment and is
 144                  * thus not an error condition.
 145                  */
 146                 if (ret < 0 && errno == EAGAIN)
 147                         return written;
 148                 if (ret < 0) {
 149                         PARA_ERROR_LOG("%s\n", strerror(errno));
 150                         return -E_DCCP_WRITE;
 151                 }
 152                 written += ret;
 153         }
 154         return written;
 155 }
 156
 157 static int queue_chunk_or_shutdown(struct dccp_client *dc, long unsigned chunk_num,
 158         size_t sent)
 159 {
 160         int ret = cq_enqueue(dc->cq, chunk_num, sent);
 161         if (ret < 0) {
 162                 PARA_NOTICE_LOG("enqueue error\n");
 163                 dccp_shutdown_client(dc);
 164         }
 165         return ret;
 166 }
 167
 168 static int send_queued_chunks(struct dccp_client *dc)
 169 {
 170         struct queued_chunk *qc;
 171         while ((qc = cq_peek(dc->cq))) {
 172                 char *buf;
 173                 size_t len;
 174                 int ret;
 175                 cq_get(qc, &buf, &len);
 176                 ret = dccp_write(dc->fd, buf, len);
 177                 if (ret < 0)
 178                         return ret;
 179                 cq_update(dc->cq, ret);
 180                 if (ret != len)
 181                         return 1;
 182                 cq_dequeue(dc->cq);
 183         }
 184         return 1;
 185 }
 186
 187 static void dccp_send(long unsigned current_chunk,
 188                 __a_unused long unsigned chunks_sent, const char *buf, size_t len)
 189 {
 190         struct dccp_client *dc, *tmp;
 191         int ret;
 192         char *header_buf;
 193         size_t header_len;
 194
 195         if (listen_fd < 0 || !len)
 196                 return;
 197
 198         list_for_each_entry_safe(dc, tmp, &clients, node) {
 199                 if (!dc->header_sent && current_chunk) {
 200                         header_buf = vss_get_header(&header_len);
 201                         if (header_buf && header_len > 0) {
 202                                 if (queue_chunk_or_shutdown(dc, -1U, 0) < 0)
 203                                         continue;
 204                         }
 205                         dc->header_sent = 1;
 206                 }
 207                 ret = send_queued_chunks(dc);
 208                 if (ret < 0) {
 209                         dccp_shutdown_client(dc);
 210                         continue;
 211                 }
 212 //              PARA_DEBUG_LOG("writing %d bytes to fd %d\n", len, dc->fd);
 213                 ret = dccp_write(dc->fd, buf, len);
 214                 if (ret < 0) {
 215                         PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
 216                         dccp_shutdown_client(dc);
 217                         continue;
 218                 }
 219                 if (ret != len)
 220                         queue_chunk_or_shutdown(dc, current_chunk, ret);
 221         }
 222 }
 223
 224 static void dccp_shutdown_clients(void)
 225 {
 226         struct dccp_client *dc, *tmp;
 227
 228         list_for_each_entry_safe(dc, tmp, &clients, node)
 229                 dccp_shutdown_client(dc);
 230 }
 231
 232 static char *dccp_info(void)
 233 {
 234         static char *buf;
 235         int num_clients = 0;
 236         struct dccp_client *dc, *tmp;
 237
 238         free(buf);
 239         list_for_each_entry_safe(dc, tmp, &clients, node)
 240                 num_clients++;
 241         buf = make_message("dccp connected clients: %d\n", num_clients);
 242         return buf;
 243 }
 244
 245 static char *dccp_help(void)
 246 {
 247         return make_message("no help available\n");
 248 }
 249
 250 /**
 251  * the init function of the dccp sender
 252  *
 253  * \param s pointer to the dccp sender struct
 254  *
 255  * It initializes all function pointers of \a s and starts
 256  * listening on the given port.
 257  */
 258 void dccp_send_init(struct sender *s)
 259 {
 260         int ret;
 261
 262         INIT_LIST_HEAD(&clients);
 263         s->info = dccp_info;
 264         s->send = dccp_send;
 265         s->pre_select = dccp_pre_select;
 266         s->post_select = dccp_post_select;
 267         s->shutdown_clients = dccp_shutdown_clients;
 268         s->help = dccp_help;
 269         s->client_cmds[SENDER_ON] = NULL;
 270         s->client_cmds[SENDER_OFF] = NULL;
 271         s->client_cmds[SENDER_DENY] = NULL;
 272         s->client_cmds[SENDER_ALLOW] = NULL;
 273         s->client_cmds[SENDER_ADD] = NULL;
 274         s->client_cmds[SENDER_DELETE] = NULL;
 275         self = s;
 276         ret = dccp_open();
 277         if (ret < 0)
 278                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 279 }