net: ipv6: Setting Router Solication Packet timeout

Running IPv6 on STM32H743 using eth_stm32_hal I had to extend
the timeout between the attempts to send Router Solicitation packets
from 1 second to 2 seconds. Else it looked liked the packet never
got sent (checked using tcpdump).

Signed-off-by: Stefan Petersen <[email protected]>

Author: spe-ciellt

subsys/net/ip/Kconfig.ipv6

@@ -156,6 +156,15 @@ config NET_IPV6_DAD
 	  The value depends on your network needs. DAD should normally
 	  be active.
 
+config NET_IPV6_RS_TIMEOUT
+	int "Timeout of Router Solicitation messaging"
+	depends on NET_IPV6_ND
+	range 1 30
+	default 1
+	help
+	  The timeout in seconds between attempts to send a Router
+	  Solicitation message at startup.
+
 config NET_IPV6_RA_RDNSS
 	bool "Support RA RDNSS option"
 	depends on NET_IPV6_ND

subsys/net/ip/net_if.c

@@ -1425,7 +1425,7 @@ static inline void net_if_ipv6_start_dad(struct net_if *iface,
 #endif /* CONFIG_NET_IPV6_DAD */
 
 #if defined(CONFIG_NET_IPV6_ND)
-#define RS_TIMEOUT (1U * MSEC_PER_SEC)
+#define RS_TIMEOUT (CONFIG_NET_IPV6_RS_TIMEOUT * MSEC_PER_SEC)
 #define RS_COUNT 3
 
 static void rs_timeout(struct k_work *work)