Ignore silently VRRP packet with a different VRID. Thanks to Samuel Melrose (https://github.com/iamacarpet/)

vrrp_net.c

@@ -252,10 +252,11 @@ int vrrp_net_vip_set(struct vrrp_net *vnet, const char *ip)
 /**
  * vrrp_net_listen() - Wait for a VRRP pkt on vnet->socket
  *
- * @return TIMER if current timer is expired
+ * @return vrrp_event_t
- * @return PKT else
+ *   TIMER if current timer is expired
+ *   another event else
  */
-int vrrp_net_listen(struct vrrp_net *vnet, struct vrrp *vrrp)
+vrrp_event_t vrrp_net_listen(struct vrrp_net *vnet, struct vrrp *vrrp)
 {
 	struct vrrp_timer *vt;
 
@@ -308,13 +309,7 @@ int vrrp_net_listen(struct vrrp_net *vnet, struct vrrp *vrrp)
 		log_debug("vrid %d :: VRRP pkt received", vrrp->vrid);
 
 		/* check if received is valid or not */
-		if (vrrp_net_recv(vnet, vrrp) > 0)
+		return vrrp_net_recv(vnet, vrrp);
-			return PKT;
-		else {
-			log_error("vrid %d :: %s", vrrp->vrid,
-				  "Received an invalid packet");
-			return INVALID;
-		}
 	}
 	else {	/* Signal or pselect error */
 		if (errno == EINTR) {
@@ -342,9 +337,9 @@ static inline void vrrp_net_invalidate_buffer(struct vrrp_net *vnet)
 /**
  * vrrp_net_recv() - read and check a received VRRP pkt advertisement
  *
- * @return len of VRRP pkt if valid, -1 if invalid
+ * @return vrrp_pkt_t
  */
-int vrrp_net_recv(struct vrrp_net *vnet, const struct vrrp *vrrp)
+vrrp_event_t vrrp_net_recv(struct vrrp_net *vnet, const struct vrrp *vrrp)
 {
 	/* fetch pkt data received to buf */
 	unsigned char buf[IP_MAXPACKET];
@@ -408,6 +403,13 @@ int vrrp_net_recv(struct vrrp_net *vnet, const struct vrrp *vrrp)
 		return INVALID;
 	}
 
+	/* check if VRID is the same as the current instance */
+	if (vrrpkt->vrid != vrrp->vrid) {
+		log_debug("vrid %d :: Invalid pkt - Invalid VRID %d",
+			 vrrp->vrid, vrrpkt->vrid);
+		return VRID_MISMATCH;
+	}
+
 	/* verify VRRP checksum */
 	int chksum = vrrpkt->chksum;	/* save checksum */
 	if (vnet->adv_checksum(vnet, vrrpkt, &vnet->__pkt.s_ipx,
@@ -420,13 +422,6 @@ int vrrp_net_recv(struct vrrp_net *vnet, const struct vrrp *vrrp)
 	/* restore checksum */
 	vrrpkt->chksum = chksum;
 
-	/* check if VRID is the same as the current instance */
-	if (vrrpkt->vrid != vrrp->vrid) {
-		log_info("vrid %d :: Invalid pkt - Invalid VRID %d",
-			 vrrp->vrid, vrrpkt->vrid);
-		return INVALID;
-	}
-
 	/* local router is the IP address owner
 	 * (Priority equals 255) 
 	 */
@@ -490,7 +485,7 @@ int vrrp_net_recv(struct vrrp_net *vnet, const struct vrrp *vrrp)
 	/* pkt is valid, keep it in internal buffer */
 	memcpy(&vnet->__pkt.adv, vrrpkt, sizeof(struct vrrphdr));
 
-	return len;
+	return PKT;
 }
 
 /**

vrrp_net.h

@@ -139,13 +139,16 @@ struct vrrp_net {
 /**
  * enum vrrp_ret - Return code used in vrrp_net_listen
  */
-enum vrrp_ret {
+enum _vrrp_event_type {
-	INVALID = -1,
+	VRID_MISMATCH = -2,	/* vrid mismatch */
-	PKT,	/* valid packet received */
+	INVALID = -1,           /* invalid pkt */
-	SIGNAL,	/* signal catch */
+	PKT,			/* valid packet */
-	TIMER	/* timer expired */
+	SIGNAL,			/* signal catch */
+	TIMER			/* timer expired */
 };
 
+typedef enum _vrrp_event_type vrrp_event_t;
+
 /*
  * funcs
  */
@@ -156,8 +159,8 @@ int vrrp_net_socket_xmit(struct vrrp_net *vnet);
 int vrrp_net_vif_getaddr(struct vrrp_net *vnet);
 int vrrp_net_vif_mtu(struct vrrp_net *vnet);
 int vrrp_net_vip_set(struct vrrp_net *vnet, const char *ip);
-int vrrp_net_listen(struct vrrp_net *vnet, struct vrrp *vrrp);
+vrrp_event_t vrrp_net_listen(struct vrrp_net *vnet, struct vrrp *vrrp);
-int vrrp_net_recv(struct vrrp_net *vnet, const struct vrrp *vrrp);
+vrrp_event_t vrrp_net_recv(struct vrrp_net *vnet, const struct vrrp *vrrp);
 int vrrp_net_send(const struct vrrp_net *vnet, struct iovec *iov, size_t len);
 
 #endif /* _VRRP_NET_ */

vrrp_state.c

@@ -143,6 +143,10 @@ int vrrp_state_backup(struct vrrp *vrrp, struct vrrp_net *vnet)
 
 		break;
 
+	case VRID_MISMATCH:
+		/* ignore VRRP pkt with different vrid */
+		break;
+
 	case INVALID:
 		log_warning("vrid %d :: %s %s, %s", vrrp->vrid,
 			    "receive an invalid advertisement packet from",
@@ -253,6 +257,10 @@ int vrrp_state_master(struct vrrp *vrrp, struct vrrp_net *vnet)
 
 		break;
 
+	case VRID_MISMATCH:
+		/* ignore VRRP pkt with different vrid */
+		break;
+
 	case INVALID:
 		log_warning("vrid %d :: invalid event", vrrp->vrid);
 		break;