zebra: Don't leak memory in rtadv.c code on shutdown

The adata variable was being leaked on shutdown since
it was calloc'ed.  There is no need to make this dynamic
memory.  Just choose a size and use that.  Add a bit
of code to ensure that if it's not large enough,
it will just stop and the developer will fix it.

Signed-off-by: Donald Sharp <[email protected]>
(cherry picked from commit 8fcacf6)

zebra/main.c

@@ -417,6 +417,8 @@ int main(int argc, char **argv)
 	zebra_vty_init();
 	access_list_init();
 	prefix_list_init();
+
+	rtadv_init();
 	rtadv_cmd_init();
 /* PTM socket */
 #ifdef ZEBRA_PTM_SUPPORT

zebra/rtadv.c

@@ -33,6 +33,7 @@
 extern struct zebra_privs_t zserv_privs;
 
 static uint32_t interfaces_configured_for_ra_from_bgp;
+#define RTADV_ADATA_SIZE 1024
 
 #if defined(HAVE_RTADV)
 
@@ -187,8 +188,9 @@ static void rtadv_send_packet(int sock, struct interface *ifp,
 	struct cmsghdr *cmsgptr;
 	struct in6_pktinfo *pkt;
 	struct sockaddr_in6 addr;
-	static void *adata = NULL;
 	unsigned char buf[RTADV_MSG_SIZE];
+	char adata[RTADV_ADATA_SIZE];
+
 	struct nd_router_advert *rtadv;
 	int ret;
 	int len = 0;
@@ -199,22 +201,6 @@ static void rtadv_send_packet(int sock, struct interface *ifp,
 	struct listnode *node;
 	uint16_t pkt_RouterLifetime;
 
-	/*
-	 * Allocate control message bufffer.  This is dynamic because
-	 * CMSG_SPACE is not guaranteed not to call a function.  Note that
-	 * the size will be different on different architectures due to
-	 * differing alignment rules.
-	 */
-	if (adata == NULL) {
-		/* XXX Free on shutdown. */
-		adata = calloc(1, CMSG_SPACE(sizeof(struct in6_pktinfo)));
-
-		if (adata == NULL) {
-			zlog_debug("%s: can't malloc control data", __func__);
-			exit(-1);
-		}
-	}
-
 	/* Logging of packet. */
 	if (IS_ZEBRA_DEBUG_PACKET)
 		zlog_debug("%s(%s:%u): Tx RA, socket %u", ifp->name,
@@ -3069,3 +3055,13 @@ uint32_t rtadv_get_interfaces_configured_from_bgp(void)
 {
 	return interfaces_configured_for_ra_from_bgp;
 }
+
+void rtadv_init(void)
+{
+	if (CMSG_SPACE(sizeof(struct in6_pktinfo)) > RTADV_ADATA_SIZE) {
+		zlog_debug("%s: RTADV_ADATA_SIZE choosen will not work on this platform, please use a larger size",
+			   __func__);
+
+		exit(-1);
+	}
+}

zebra/rtadv.h

@@ -435,6 +435,7 @@ extern void zebra_interface_radv_enable(ZAPI_HANDLER_ARGS);
 
 extern uint32_t rtadv_get_interfaces_configured_from_bgp(void);
 extern bool rtadv_compiled_in(void);
+extern void rtadv_init(void);
 
 #ifdef __cplusplus
 }