From 84110f4f7760c4f0a9c3e394447304e7cd2384a3 Mon Sep 17 00:00:00 2001
From: Perette Barella <perette@barella.org>
Date: Tue, 19 Jan 2016 13:22:13 -0500
Subject: [PATCH] libavformat/tcp.c : add send_buffer_size and recv_buffer_size
 options

adds two new options that may be set via the dictionary:

- send_buffer_size
- recv_buffer_size

When present, setsockopt() is used with SO_SNDBUF and SO_RCVBUF to set
socket buffer sizes.  I chose to make send and receive independent
because buffering requirements are often asymmetric.

Errors in setting the buffer size mean the socket will use its
default, so they are ignored.

There is no sanity checking on values, as the kernel/socket layers
already impose reasonable limits if asked for something crazy.

Rationale for enlarging receive buffers is to reduce susceptibility
to intermittent network delays/congestion.  I added setting the send
buffer for symmetry.

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 doc/protocols.texi |  6 ++++++
 libavformat/tcp.c  | 13 +++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/doc/protocols.texi b/doc/protocols.texi
index 8b2e310b0a8..05c4bdbfc98 100644
--- a/doc/protocols.texi
+++ b/doc/protocols.texi
@@ -1147,6 +1147,12 @@ than this time interval, raise error.
 
 @item listen_timeout=@var{milliseconds}
 Set listen timeout, expressed in milliseconds.
+
+@item recv_buffer_size=@var{bytes}
+Set receive buffer size, expressed bytes.
+
+@item send_buffer_size=@var{bytes}
+Set send buffer size, expressed bytes.
 @end table
 
 The following example shows how to setup a listening TCP connection
diff --git a/libavformat/tcp.c b/libavformat/tcp.c
index e02c64b8001..5738690843a 100644
--- a/libavformat/tcp.c
+++ b/libavformat/tcp.c
@@ -39,6 +39,8 @@ typedef struct TCPContext {
     int open_timeout;
     int rw_timeout;
     int listen_timeout;
+    int recv_buffer_size;
+    int send_buffer_size;
 } TCPContext;
 
 #define OFFSET(x) offsetof(TCPContext, x)
@@ -48,6 +50,8 @@ static const AVOption options[] = {
     { "listen",          "Listen for incoming connections",  OFFSET(listen),         AV_OPT_TYPE_INT, { .i64 = 0 },     0,       2,       .flags = D|E },
     { "timeout",     "set timeout (in microseconds) of socket I/O operations", OFFSET(rw_timeout),     AV_OPT_TYPE_INT, { .i64 = -1 },         -1, INT_MAX, .flags = D|E },
     { "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 },
     { NULL }
 };
 
@@ -150,6 +154,15 @@ static int tcp_open(URLContext *h, const char *uri, int flags)
 
     h->is_streamed = 1;
     s->fd = fd;
+    /* Set the socket's send or receive buffer sizes, if specified.
+       If unspecified or setting fails, system default is used. */
+    if (s->recv_buffer_size > 0) {
+        setsockopt (fd, SOL_SOCKET, SO_RCVBUF, &s->recv_buffer_size, sizeof (s->recv_buffer_size));
+    }
+    if (s->send_buffer_size > 0) {
+        setsockopt (fd, SOL_SOCKET, SO_SNDBUF, &s->send_buffer_size, sizeof (s->send_buffer_size));
+    }
+
     freeaddrinfo(ai);
     return 0;
 
-- 
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