From e442a69fc134e6f1ebd72b6f3d2513b21106da30 Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date: Fri, 26 Jan 2024 01:44:27 +0100
Subject: [PATCH] cluster: try make the cluster socket high-priority

The heartbeat messages, notably, should really not be lost, otherwise the
cluster will dismantle itself if some very-high trafic is filling packet
queues.
---
 cluster.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/cluster.c b/cluster.c
index 2ebe4b3..d68918a 100644
--- a/cluster.c
+++ b/cluster.c
@@ -133,6 +133,9 @@ int cluster_init()
 	opt = 0;	// Turn off multicast loopback.
 	setsockopt(cluster_sockfd, IPPROTO_IP, IP_MULTICAST_LOOP, &opt, sizeof(opt));
 
+	opt = 7;	// Highest priority to avoid getting hit by high-traffic
+	setsockopt(cluster_sockfd, SOL_SOCKET, SO_PRIORITY, &opt, sizeof(opt));
+
 	if (config->cluster_mcast_ttl != 1)
 	{
 		uint8_t ttl = 0;