From: Hans Dedecker <dedeckeh@gmail.com>
Date: Fri, 19 Apr 2019 11:16:58 +0000 (+0200)
Subject: router: fix dns search list option
X-Git-Url: https://git.librecmc.org/?p=oweals%2Fodhcpd.git;a=commitdiff_plain;h=6633efeb8196853503305c2714ba6830c8d9c70b

router: fix dns search list option

Fix regression issue introduced in commit 0523bdd as empty DNS search
list option was sent making the RA message invalid

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
---

diff --git a/src/router.c b/src/router.c
index a897d5b..3a6b121 100644
--- a/src/router.c
+++ b/src/router.c
@@ -587,7 +587,7 @@ static int send_router_advert(struct interface *iface, const struct in6_addr *fr
 	/* DNS options */
 	if (iface->ra_dns) {
 		struct in6_addr dns_pref, *dns_addr = NULL;
-		size_t dns_cnt = 0, search_padded = 0, search_len = iface->search_len;
+		size_t dns_cnt = 0, search_len = iface->search_len;
 		uint8_t *search_domain = iface->search;
 
 		/* DNS Recursive DNS */
@@ -622,18 +622,16 @@ static int send_router_advert(struct interface *iface, const struct in6_addr *fr
 			}
 		}
 
-		if (search_len > 0)
-			search_padded = ((search_len + 7) & (~7)) + 8;
-
-		search_sz = sizeof(*search) + search_padded;
+		if (search_len > 0) {
+			size_t search_padded = ((search_len + 7) & (~7)) + 8;
 
-		search = alloca(search_sz);
-		memset(search, 0, search_sz);
-		search->type = ND_OPT_DNS_SEARCH;
-		search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0;
-		search->lifetime = htonl(lifetime);
+			search_sz = sizeof(*search) + search_padded;
 
-		if (search_len > 0) {
+			search = alloca(search_sz);
+			memset(search, 0, search_sz);
+			search->type = ND_OPT_DNS_SEARCH;
+			search->len = search_len ? ((sizeof(*search) + search_padded) / 8) : 0;
+			search->lifetime = htonl(lifetime);
 			memcpy(search->name, search_domain, search_len);
 			memset(&search->name[search_len], 0, search_padded - search_len);
 		}