Add support for multiple VLANs on same interface

A common case is to have multiple VLANs on a bridge, in such setups we
want to treat each VLAN as if we run in proxy-mode on a VLAN interface
on top of the bridge.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

Author: troglobit

src/cfparse.y

@@ -164,7 +164,7 @@ ifmod	: DISABLE		{ ifi->ifi_flags |= IFIF_DISABLED; }
 	{
 	    if ($2 < 1 || $2 > 4094)
 		fatal("Invalid VLAN ID [1,4094]");
-	    ifi->ifi_vlan = $2;
+	    ifi = config_iface_vlan(ifi, $2);
 	}
 	;
 

src/config.c

@@ -138,6 +138,31 @@ struct ifi *config_iface_add(char *ifname)
     return ifi;
 }
 
+/*
+ * Called by parser for 'vlan NUM', may create an interface clone of
+ * the current interface with already learned settings.
+ */
+struct ifi *config_iface_vlan(struct ifi *ifi, int vid)
+{
+    struct ifi *clone;
+
+    if (ifi->ifi_vlan == 0) {
+	ifi->ifi_vlan = vid;
+	return ifi;
+    }
+
+    clone = malloc(sizeof(*clone));
+    if (!clone)
+	logit(LOG_ERR, errno, "failed cloning %s for new VLAN %d", ifi->ifi_name, vid);
+
+    memcpy(clone, ifi, sizeof(*clone));
+    TAILQ_INSERT_TAIL(&ifaces, clone, ifi_link);
+
+    clone->ifi_vlan = vid;
+
+    return clone;
+}
+
 static struct ifi *addr_add(int ifindex, struct sockaddr *sa, unsigned int flags)
 {
     struct sockaddr_in *sin = (struct sockaddr_in *)sa;

src/defs.h

@@ -160,6 +160,7 @@ extern void             config_init(void);
 extern void		config_set_ifflag(uint32_t);
 extern struct ifi      *config_iface_iter(int);
 extern struct ifi      *config_iface_add(char *);
+extern struct ifi      *config_iface_vlan(struct ifi *, int);
 extern void             config_iface_addr_del(int, struct sockaddr *);
 extern struct ifi      *config_find_ifname(char *);
 extern struct ifi      *config_find_ifaddr(in_addr_t);