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;
  67
  68         if (!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         /*
  76          * Bypass unused CCID paths: the sender does not receive application data
  77          * from the client; by shutting down this unused communication path we can
  78          * reduce processing costs a bit. See analogous comment in dccp_recv.c.
  79          */
  80         if (shutdown(ret, SHUT_RD) < 0) {
  81                 PARA_ERROR_LOG("shutdown(SHUT_RD): %s\n", strerror(errno));
  82                 return;
  83         }
  84         dc = para_calloc(sizeof(struct dccp_client));
  85         dc->fd = ret;
  86         dc->name = make_message("%s", remote_name(dc->fd));
  87         PARA_NOTICE_LOG("connection from %s\n", dc->name);
  88         para_list_add(&dc->node, &clients);
  89         add_close_on_fork_list(dc->fd);
  90         mark_fd_nonblocking(dc->fd);
  91         dc->cq = cq_new(DCCP_MAX_PENDING_BYTES);
  92 }
  93
  94 static int dccp_open(void)
  95 {
  96         int ret = para_listen(AF_UNSPEC, IPPROTO_DCCP, conf.dccp_port_arg);
  97
  98         if (ret < 0)
  99                 return ret;
 100         listen_fd = ret;
 101         add_close_on_fork_list(listen_fd);
 102         mark_fd_nonblocking(listen_fd);
 103         return 1;
 104 }
 105
 106 static void dccp_shutdown_client(struct dccp_client *dc)
 107 {
 108         PARA_DEBUG_LOG("shutting down %s (fd %d)\n", dc->name, dc->fd);
 109         free(dc->name);
 110         close(dc->fd);
 111         del_close_on_fork_list(dc->fd);
 112         cq_destroy(dc->cq);
 113         list_del(&dc->node);
 114         free(dc);
 115 }
 116
 117 /*
 118  * ret: Negative on errors, zero if nothing was written and write returned
 119  * EAGAIN, number of bytes written else.
 120  */
 121 static int dccp_write(int fd, const char *buf, size_t len)
 122 {
 123         size_t written = 0;
 124         int ret = 0;
 125
 126         while (written < len) {
 127                 ret = write(fd, buf + written, PARA_MIN(1024, len - written));
 128                 /*
 129                  * Error handling: CCID3 has a sending wait queue which fills up and is
 130                  * emptied asynchronously. The EAGAIN case means that there is currently
 131                  * no space in the wait queue, but this can change at any moment and is
 132                  * thus not an error condition.
 133                  */
 134                 if (ret < 0 && errno == EAGAIN)
 135                         return written;
 136                 if (ret < 0) {
 137                         PARA_ERROR_LOG("%s\n", strerror(errno));
 138                         return -E_DCCP_WRITE;
 139                 }
 140                 written += ret;
 141         }
 142         return written;
 143 }
 144
 145 static int queue_chunk_or_shutdown(struct dccp_client *dc, long unsigned chunk_num,
 146         size_t sent)
 147 {
 148         int ret = cq_enqueue(dc->cq, chunk_num, sent);
 149         if (ret < 0) {
 150                 PARA_NOTICE_LOG("enqueue error\n");
 151                 dccp_shutdown_client(dc);
 152         }
 153         return ret;
 154 }
 155
 156 static int send_queued_chunks(struct dccp_client *dc)
 157 {
 158         struct queued_chunk *qc;
 159         while ((qc = cq_peek(dc->cq))) {
 160                 char *buf;
 161                 size_t len;
 162                 int ret;
 163                 cq_get(qc, &buf, &len);
 164                 ret = dccp_write(dc->fd, buf, len);
 165                 if (ret < 0)
 166                         return ret;
 167                 cq_update(dc->cq, ret);
 168                 if (ret != len)
 169                         return 1;
 170                 cq_dequeue(dc->cq);
 171         }
 172         return 1;
 173 }
 174
 175 static void dccp_send(long unsigned current_chunk,
 176                 __a_unused long unsigned chunks_sent, const char *buf, size_t len)
 177 {
 178         struct dccp_client *dc, *tmp;
 179         int ret;
 180         char *header_buf;
 181         size_t header_len;
 182
 183         if (listen_fd < 0 || !len)
 184                 return;
 185
 186         list_for_each_entry_safe(dc, tmp, &clients, node) {
 187                 if (!dc->header_sent && current_chunk) {
 188                         header_buf = vss_get_header(&header_len);
 189                         if (header_buf && header_len > 0) {
 190                                 if (queue_chunk_or_shutdown(dc, -1U, 0) < 0)
 191                                         continue;
 192                         }
 193                         dc->header_sent = 1;
 194                 }
 195                 ret = send_queued_chunks(dc);
 196                 if (ret < 0) {
 197                         dccp_shutdown_client(dc);
 198                         continue;
 199                 }
 200 //              PARA_DEBUG_LOG("writing %d bytes to fd %d\n", len, dc->fd);
 201                 ret = dccp_write(dc->fd, buf, len);
 202                 if (ret < 0) {
 203                         PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
 204                         dccp_shutdown_client(dc);
 205                         continue;
 206                 }
 207                 if (ret != len)
 208                         queue_chunk_or_shutdown(dc, current_chunk, ret);
 209         }
 210 }
 211
 212 static void dccp_shutdown_clients(void)
 213 {
 214         struct dccp_client *dc, *tmp;
 215
 216         list_for_each_entry_safe(dc, tmp, &clients, node)
 217                 dccp_shutdown_client(dc);
 218 }
 219
 220 static char *dccp_info(void)
 221 {
 222         static char *buf;
 223         int num_clients = 0;
 224         struct dccp_client *dc, *tmp;
 225
 226         free(buf);
 227         list_for_each_entry_safe(dc, tmp, &clients, node)
 228                 num_clients++;
 229         buf = make_message("dccp connected clients: %d\n", num_clients);
 230         return buf;
 231 }
 232
 233 static char *dccp_help(void)
 234 {
 235         return make_message("no help available\n");
 236 }
 237
 238 /**
 239  * the init function of the dccp sender
 240  *
 241  * \param s pointer to the dccp sender struct
 242  *
 243  * It initializes all function pointers of \a s and starts
 244  * listening on the given port.
 245  */
 246 void dccp_send_init(struct sender *s)
 247 {
 248         int ret;
 249
 250         INIT_LIST_HEAD(&clients);
 251         s->info = dccp_info;
 252         s->send = dccp_send;
 253         s->pre_select = dccp_pre_select;
 254         s->post_select = dccp_post_select;
 255         s->shutdown_clients = dccp_shutdown_clients;
 256         s->help = dccp_help;
 257         s->client_cmds[SENDER_ON] = NULL;
 258         s->client_cmds[SENDER_OFF] = NULL;
 259         s->client_cmds[SENDER_DENY] = NULL;
 260         s->client_cmds[SENDER_ALLOW] = NULL;
 261         s->client_cmds[SENDER_ADD] = NULL;
 262         s->client_cmds[SENDER_DELETE] = NULL;
 263         self = s;
 264         ret = dccp_open();
 265         if (ret < 0) {
 266                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 267                 s->status = SENDER_OFF;
 268         } else
 269                 s->status = SENDER_ON;
 270 }