ND Route Information Option prefix is optional

rsmarples · rsmarples · commit 6dcb1569fc78 · 2025-09-13T12:45:50.000+01:00
As the length could be zero and is RFC compliant. Fixes #527.
diff --git a/src/dhcpcd-definitions-small.conf b/src/dhcpcd-definitions-small.conf
@@ -74,7 +74,7 @@ embed		byte			length
 # bits 4 and 5 are route preference
 embed		bitflags=00011		prf
 embed		uint32			lifetime
-embed		truncated ip6address	prefix
+embed		optional truncated ip6address	prefix
 
 # ND6 options, RFC6101
 definend 25	index embed		rdnss
diff --git a/src/dhcpcd-definitions.conf b/src/dhcpcd-definitions.conf
@@ -417,7 +417,7 @@ embed		byte			length
 # bits 4 and 5 are route preference
 embed		bitflags=00011		prf
 embed		uint32			lifetime
-embed		truncated ip6address	prefix
+embed		optional truncated ip6address	prefix
 
 # ND6 options, RFC6101
 definend 25	index embed		rdnss
diff --git a/src/if-options.c b/src/if-options.c
@@ -2093,7 +2093,7 @@ parse_option(struct dhcpcd_ctx *ctx, const char *ifname, struct if_options *ifo,
 				t |= OT_RESERVED;
 			}
 		}
-		if (t & OT_TRUNCATED && t != (OT_ADDRIPV6 | OT_TRUNCATED)) {
+		if (t & OT_TRUNCATED && !(t & OT_ADDRIPV6)) {
 			logerrx("truncated only works for ip6address");
 			return -1;
 		}

Original file line number	Diff line number	Diff line change
`@@ -2093,7 +2093,7 @@ parse_option(struct dhcpcd_ctx ctx, const char ifname, struct if_options *ifo,`
`2093`	`2093`	`t \|= OT_RESERVED;`
`2094`	`2094`	`}`
`2095`	`2095`	`}`
`2096`		`- if (t & OT_TRUNCATED && t != (OT_ADDRIPV6 \| OT_TRUNCATED)) {`
	`2096`	`+ if (t & OT_TRUNCATED && !(t & OT_ADDRIPV6)) {`
`2097`	`2097`	`logerrx("truncated only works for ip6address");`
`2098`	`2098`	`return -1;`
`2099`	`2099`	`}`