libav/udp.c

   1 /*
   2  * UDP prototype streaming system
   3  * Copyright (c) 2000 Fabrice Bellard.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19 #include "avformat.h"
  20 #include <unistd.h>
  21 #include <sys/types.h>
  22 #include <sys/socket.h>
  23 #include <netinet/in.h>
  24 #include <arpa/inet.h>
  25 #include <netdb.h>
  26
  27 typedef struct {
  28     int udp_socket;
  29     int max_payload_size; /* in bytes */
  30 } UDPContext;
  31
  32 #define UDP_TX_BUF_SIZE 32768
  33
  34 /* put it in UDP context */
  35 static struct sockaddr_in dest_addr;
  36
  37 /* return non zero if error */
  38 static int udp_open(URLContext *h, const char *uri, int flags)
  39 {
  40     int local_port = 0;
  41     struct sockaddr_in my_addr;
  42     const char *p, *q;
  43     char hostname[1024];
  44     int port, udp_socket, tmp;
  45     struct hostent *hp;
  46     UDPContext *s;
  47
  48     h->is_streamed = 1;
  49
  50     if (!(flags & URL_WRONLY))
  51         return -EIO;
  52
  53     /* fill the dest addr */
  54     p = uri;
  55     if (!strstart(p, "udp:", &p))
  56         return -1;
  57     q = strchr(p, ':');
  58     if (!q)
  59         return -1;
  60     memcpy(hostname, p, q - p);
  61     hostname[q - p] = '\0';
  62     port = strtol(q+1, NULL, 10);
  63     if (port <= 0)
  64         return -1;
  65
  66     dest_addr.sin_family = AF_INET;
  67     dest_addr.sin_port = htons(port);
  68     if ((inet_aton(hostname, &dest_addr.sin_addr)) == 0) {
  69         hp = gethostbyname(hostname);
  70         if (!hp)
  71             return -1;
  72         memcpy ((char *) &dest_addr.sin_addr, hp->h_addr, hp->h_length);
  73     }
  74
  75     udp_socket = socket(PF_INET, SOCK_DGRAM, 0);
  76     if (udp_socket < 0)
  77         return -1;
  78
  79     my_addr.sin_family = AF_INET;
  80     my_addr.sin_port = htons(local_port);
  81     my_addr.sin_addr.s_addr = htonl (INADDR_ANY);
  82
  83     /* the bind is needed to give a port to the socket now */
  84     if (bind(udp_socket,(struct sockaddr *)&my_addr, sizeof(my_addr)) < 0)
  85         goto fail;
  86
  87     /* limit the tx buf size to limit latency */
  88
  89     tmp = UDP_TX_BUF_SIZE;
  90     if (setsockopt(udp_socket, SOL_SOCKET, SO_SNDBUF, &tmp, sizeof(tmp)) < 0) {
  91         perror("setsockopt sndbuf");
  92         goto fail;
  93     }
  94
  95     s = av_malloc(sizeof(UDPContext));
  96     if (!s)
  97         return -ENOMEM;
  98     h->priv_data = s;
  99     s->udp_socket = udp_socket;
 100     h->packet_size = 1500;
 101     return 0;
 102  fail:
 103     return -EIO;
 104 }
 105
 106 int udp_close(URLContext *h)
 107 {
 108     UDPContext *s = h->priv_data;
 109     close(s->udp_socket);
 110     return 0;
 111 }
 112
 113 int udp_write(URLContext *h, UINT8 *buf, int size)
 114 {
 115     UDPContext *s = h->priv_data;
 116     int ret, len, size1;
 117
 118     /* primitive way to avoid big packets */
 119     size1 = size;
 120     while (size > 0) {
 121         len = size;
 122         if (len > h->packet_size)
 123             len = h->packet_size;
 124
 125         ret = sendto (s->udp_socket, buf, len, 0,
 126                       (struct sockaddr *) &dest_addr,
 127                       sizeof (dest_addr));
 128         if (ret < 0)
 129             perror("sendto");
 130         buf += len;
 131         size -= len;
 132     }
 133     return size1 - size;
 134 }
 135
 136 URLProtocol udp_protocol = {
 137     "udp",
 138     udp_open,
 139     NULL, /* read */
 140     udp_write,
 141     NULL, /* seek */
 142     udp_close,
 143 };