From: Paul Donald <newtwen+github@gmail.com>
Date: Fri, 10 Oct 2025 11:45:48 +0000 (+0200)
Subject: config: cap ra_reachabletime to RFC maximum instead of logging error
X-Git-Url: http://git.openwrt.org/?a=commitdiff_plain;h=208eb10307c101346065c2127092f0b222d763d0;p=project%2Fodhcpd.git

config: cap ra_reachabletime to RFC maximum instead of logging error

Signed-off-by: Paul Donald <newtwen+github@gmail.com>
Link: https://github.com/openwrt/odhcpd/pull/225
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---

diff --git a/src/config.c b/src/config.c
index 7f11281..0441b12 100644
--- a/src/config.c
+++ b/src/config.c
@@ -1359,11 +1359,13 @@ int config_parse_interface(void *data, size_t len, const char *name, bool overwr
 	if ((c = tb[IFACE_ATTR_RA_REACHABLETIME])) {
 		uint32_t ra_reachabletime = blobmsg_get_u32(c);
 
-		if (ra_reachabletime <= 3600000)
-			iface->ra_reachabletime = ra_reachabletime;
-		else
-			syslog(LOG_ERR, "Invalid %s value configured for interface '%s'",
-					iface_attrs[IFACE_ATTR_RA_REACHABLETIME].name, iface->name);
+		/* RFC4861 §6.2.1 : AdvReachableTime : 
+		 * MUST be no greater than 3,600,000 msec
+		 */
+		iface->ra_reachabletime = ra_reachabletime <= AdvReachableTime ? ra_reachabletime : AdvReachableTime;
+		if(ra_reachabletime > AdvReachableTime)
+			syslog(LOG_WARNING, "Clamped invalid %s value configured for interface '%s' to %d",
+					iface_attrs[IFACE_ATTR_RA_REACHABLETIME].name, iface->name, iface->ra_reachabletime);
 	}
 
 	if ((c = tb[IFACE_ATTR_RA_RETRANSTIME])) {
diff --git a/src/router.h b/src/router.h
index 6609f43..2cd5469 100644
--- a/src/router.h
+++ b/src/router.h
@@ -66,6 +66,10 @@ struct icmpv6_opt {
 	define is used to cap values to a sane ceiling, i.e. ND_VALID_LIMIT.
 */
 #define RouterLifetime					5400
+/* RFC4861 §6.2.1 : AdvReachableTime : 
+ * MUST be no greater than 3,600,000 msec
+ */
+#define AdvReachableTime				3600000
 
 #define ND_RA_FLAG_PROXY		0x4
 #define ND_RA_PREF_HIGH			(1 << 3)