[PATCH 1/4] ipaccess: Enable TCP keepalive by default on all BTS connections

[Jacob Erlbeck]

From: Daniel Willmann <daniel at totalueberwachung.de>

This way we can find out fast if the connection is broken.

Ticket: OW#1060
---
 src/input/ipaccess.c |   35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

diff --git a/src/input/ipaccess.c b/src/input/ipaccess.c
index 9722b2f..8f9865e 100644
--- a/src/input/ipaccess.c
+++ b/src/input/ipaccess.c
@@ -28,6 +28,7 @@
 #include <stdlib.h>
 #include <stdbool.h>
 #include <errno.h>
+#include <netinet/tcp.h>
 #include <string.h>
 #include <time.h>
 #include <sys/fcntl.h>
@@ -50,6 +51,10 @@ static void *tall_ipa_ctx;
 
 #define TS1_ALLOC_SIZE	900
 
+#define DEFAULT_TCP_KEEPALIVE_IDLE_TIMEOUT 30
+#define DEFAULT_TCP_KEEPALIVE_INTERVAL     3
+#define DEFAULT_TCP_KEEPALIVE_RETRY_COUNT  10
+
 /*
  * Common propietary IPA messages:
  *      - PONG: in reply to PING.
@@ -610,7 +615,7 @@ static int ipaccess_bsc_oml_cb(struct ipa_server_link *link, int fd)
 {
 	int ret;
 	int idx = 0;
-	int i;
+	int i, val;
 	struct e1inp_line *line;
 	struct e1inp_ts *e1i_ts;
 	struct osmo_fd *bfd;
@@ -643,6 +648,34 @@ static int ipaccess_bsc_oml_cb(struct ipa_server_link *link, int fd)
 		goto err_line;
 	}
 
+	/* Enable TCP keepalive to find out if the connection is gone */
+	val = 1;
+	ret = setsockopt(bfd->fd, SOL_SOCKET, SO_KEEPALIVE, &val, sizeof(val));
+	if (ret < 0)
+		LOGP(DLINP, LOGL_NOTICE, "Failed to set keepalive: %s\n",
+		     strerror(errno));
+	else
+		LOGP(DLINP, LOGL_NOTICE, "Keepalive is set: %i\n", ret);
+
+#if defined(TCP_KEEPIDLE) && defined(TCP_KEEPINTVL) && defined(TCP_KEEPCNT)
+	/* The following options are not portable! */
+	val = DEFAULT_TCP_KEEPALIVE_IDLE_TIMEOUT;
+	ret = setsockopt(bfd->fd, IPPROTO_TCP, TCP_KEEPIDLE, &val, sizeof(val));
+	if (ret < 0)
+		LOGP(DLINP, LOGL_NOTICE, "Failed to set keepalive idle time: %s\n",
+		     strerror(errno));
+	val = DEFAULT_TCP_KEEPALIVE_INTERVAL;
+	ret = setsockopt(bfd->fd, IPPROTO_TCP, TCP_KEEPINTVL, &val, sizeof(val));
+	if (ret < 0)
+		LOGP(DLINP, LOGL_NOTICE, "Failed to set keepalive interval: %s\n",
+		     strerror(errno));
+	val = DEFAULT_TCP_KEEPALIVE_RETRY_COUNT;
+	ret = setsockopt(bfd->fd, IPPROTO_TCP, TCP_KEEPCNT, &val, sizeof(val));
+	if (ret < 0)
+		LOGP(DLINP, LOGL_NOTICE, "Failed to set keepalive count: %s\n",
+		     strerror(errno));
+#endif
+
 	/* Request ID. FIXME: request LOCATION, HW/SW VErsion, Unit Name, Serno */
 	ret = ipaccess_send_id_req(bfd->fd);
 	if (ret < 0) {
-- 
1.7.9.5