avformat/tcp: add option to enable TCP_NODELAY

This can reduce latency and increase throughput, particularly on high
latency networks.

Signed-off-by: Aman Gupta <aman@tmm1.net>
Reviewed-by: Jeyapal, Karthick <kjeyapal@akamai.com>

doc/protocols.texi

@@ -1242,6 +1242,9 @@ Set receive buffer size, expressed bytes.
 
 @item send_buffer_size=@var{bytes}
 Set send buffer size, expressed bytes.
+
+@item tcp_nodelay=@var{1|0}
+Set TCP_NODELAY to disable Nagle's algorithm. Default value is 0.
 @end table
 
 The following example shows how to setup a listening TCP connection

libavformat/network.h

@@ -59,6 +59,7 @@ int ff_neterrno(void);
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
+#include <netinet/tcp.h>
 #include <netdb.h>
 
 #define ff_neterrno() AVERROR(errno)

libavformat/tcp.c

@@ -41,6 +41,7 @@ typedef struct TCPContext {
     int listen_timeout;
     int recv_buffer_size;
     int send_buffer_size;
+    int tcp_nodelay;
 } TCPContext;
 
 #define OFFSET(x) offsetof(TCPContext, x)
@@ -52,6 +53,7 @@ static const AVOption options[] = {
     { "listen_timeout",  "Connection awaiting timeout (in milliseconds)",      OFFSET(listen_timeout), AV_OPT_TYPE_INT, { .i64 = -1 },         -1, INT_MAX, .flags = D|E },
     { "send_buffer_size", "Socket send buffer size (in bytes)",                OFFSET(send_buffer_size), AV_OPT_TYPE_INT, { .i64 = -1 },         -1, INT_MAX, .flags = D|E },
     { "recv_buffer_size", "Socket receive buffer size (in bytes)",             OFFSET(recv_buffer_size), AV_OPT_TYPE_INT, { .i64 = -1 },         -1, INT_MAX, .flags = D|E },
+    { "tcp_nodelay", "Use TCP_NODELAY to disable nagle's algorithm",           OFFSET(tcp_nodelay), AV_OPT_TYPE_BOOL, { .i64 = 0 },             0, 1, .flags = D|E },
     { NULL }
 };
 
@@ -148,6 +150,9 @@ static int tcp_open(URLContext *h, const char *uri, int flags)
     if (s->send_buffer_size > 0) {
         setsockopt (fd, SOL_SOCKET, SO_SNDBUF, &s->send_buffer_size, sizeof (s->send_buffer_size));
     }
+    if (s->tcp_nodelay > 0) {
+        setsockopt (fd, IPPROTO_TCP, TCP_NODELAY, &s->tcp_nodelay, sizeof (s->tcp_nodelay));
+    }
 
     if (s->listen == 2) {
         // multi-client