From 99882bc5c797bb199f55491d3609b77e79534da5 Mon Sep 17 00:00:00 2001
From: Ian Gulliver <flamingcow@gmail.com>
Date: Thu, 25 Feb 2016 17:27:07 -0800
Subject: [PATCH] Enable socket keepalives.

---
 adsbus/Makefile   |  2 +-
 adsbus/incoming.c |  3 +++
 adsbus/outgoing.c |  2 ++
 adsbus/socket.c   | 24 ++++++++++++++++++++++++
 adsbus/socket.h   |  3 +++
 5 files changed, 33 insertions(+), 1 deletion(-)
 create mode 100644 adsbus/socket.c
 create mode 100644 adsbus/socket.h

diff --git a/adsbus/Makefile b/adsbus/Makefile
index 781104b..3c1dba0 100644
--- a/adsbus/Makefile
+++ b/adsbus/Makefile
@@ -5,7 +5,7 @@ LIBS ?= -ljansson -lprotobuf-c
 
 OBJ_NETWORK = incoming.o outgoing.o receive.o send.o
 OBJ_PROTOCOL = airspy_adsb.o beast.o json.o proto.o raw.o stats.o
-OBJ_UTIL = buf.o hex.o opts.o packet.o peer.o rand.o resolve.o server.o uuid.o wakeup.o
+OBJ_UTIL = buf.o hex.o opts.o packet.o peer.o rand.o resolve.o server.o socket.o uuid.o wakeup.o
 OBJ_PROTO = adsb.pb-c.o
 
 all: adsbus
diff --git a/adsbus/incoming.c b/adsbus/incoming.c
index a6d68c5..84ff62a 100644
--- a/adsbus/incoming.c
+++ b/adsbus/incoming.c
@@ -12,6 +12,7 @@
 
 #include "peer.h"
 #include "resolve.h"
+#include "socket.h"
 #include "wakeup.h"
 #include "uuid.h"
 
@@ -65,6 +66,8 @@ static void incoming_handler(struct peer *peer) {
 			local_hbuf, local_sbuf,
 			peer_hbuf, peer_sbuf);
 
+	socket_init(fd);
+
 	incoming->handler(fd, incoming->passthrough, NULL);
 }
 
diff --git a/adsbus/outgoing.c b/adsbus/outgoing.c
index 2495ff1..0434fec 100644
--- a/adsbus/outgoing.c
+++ b/adsbus/outgoing.c
@@ -10,6 +10,7 @@
 
 #include "peer.h"
 #include "resolve.h"
+#include "socket.h"
 #include "wakeup.h"
 #include "uuid.h"
 
@@ -89,6 +90,7 @@ static void outgoing_connect_result(struct outgoing *outgoing, int result) {
 		case 0:
 			fprintf(stderr, "O %s: Connected to %s/%s\n", outgoing->id, hbuf, sbuf);
 			freeaddrinfo(outgoing->addrs);
+			socket_init(outgoing->peer.fd);
 			outgoing->attempt = 0;
 			int fd = outgoing->peer.fd;
 			outgoing->peer.fd = -1;
diff --git a/adsbus/socket.c b/adsbus/socket.c
new file mode 100644
index 0000000..865638c
--- /dev/null
+++ b/adsbus/socket.c
@@ -0,0 +1,24 @@
+#include <assert.h>
+#include <errno.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include "socket.h"
+
+void socket_init(int fd) {
+	int optval = 1;
+	int err = setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &optval, sizeof(optval));
+	if (err == -1 && errno == ENOTSOCK) {
+		return;
+	}
+	assert(!err);
+
+	optval = 30;
+	assert(!setsockopt(fd, IPPROTO_TCP, TCP_KEEPIDLE, &optval, sizeof(optval)));
+	optval = 10;
+	assert(!setsockopt(fd, IPPROTO_TCP, TCP_KEEPINTVL, &optval, sizeof(optval)));
+	optval = 3;
+	assert(!setsockopt(fd, IPPROTO_TCP, TCP_KEEPCNT, &optval, sizeof(optval)));
+}
diff --git a/adsbus/socket.h b/adsbus/socket.h
new file mode 100644
index 0000000..9993af3
--- /dev/null
+++ b/adsbus/socket.h
@@ -0,0 +1,3 @@
+#pragma once
+
+void socket_init(int);