wifi-1737: Restrict DHCP Sniffing to a max of 4 vlans

Partial fix for wifi-1737:
Use of current DHCP sniffing library from opensync increases
memory footprint of nm with increased number of vlans.
This patch restricts DHCP sniffing on a maximum of 4 vlans.
This is a workaround and actual fix would be to use a better
packet filter such as eBPF

Signed-off-by: Yashvardhan <[email protected]>

Author: yashvardhan-netex

feeds/wlan-ap/opensync/src/platform/openwrt/src/netifd/inc/inet_conf.h

@@ -6,7 +6,9 @@
 #include "netifd.h"
 #include "inet_iface.h"
 
-struct netifd_iface *netifd_add_inet_conf(struct schema_Wifi_Inet_Config *iconf);
+#define DHCP_SNIFF_MAX_VLAN 4
+
+void netifd_add_inet_conf(struct schema_Wifi_Inet_Config *iconf);
 void netifd_del_inet_conf(struct schema_Wifi_Inet_Config *old_rec);
 struct netifd_iface *netifd_modify_inet_conf(struct schema_Wifi_Inet_Config *iconf);
 bool netifd_inet_config_set(struct netifd_iface *piface);

feeds/wlan-ap/opensync/src/platform/openwrt/src/netifd/src/inet_conf.c

@@ -6,45 +6,58 @@
 
 #include "inet_conf.h"
 
-struct netifd_iface* netifd_add_inet_conf(struct schema_Wifi_Inet_Config *iconf)
-{
+static int vlan_count = 0;
 
+void netifd_add_inet_conf(struct schema_Wifi_Inet_Config *iconf)
+{
 	struct netifd_iface *piface = NULL;
 
+	if (strcmp(iconf->if_type, "bridge") && strcmp(iconf->if_type, "vlan")) {
+		return;
+	}
+
 	piface = netifd_iface_get_by_name(iconf->if_name);
-	if (piface == NULL)
-	{
+
+	if (piface)
+		return;
+
+	if (!strcmp(iconf->if_name, "wan") || !strcmp(iconf->if_name, "lan")) {
 		piface = netifd_iface_new(iconf->if_name, iconf->if_type);
-		if (piface == NULL)
-		{
+		if (!piface) {
 			LOG(ERR, "netifd_add_inet_conf: %s: Unable to create interface.", iconf->if_name);
-			return NULL;
+			return;
 		}
-
-		if (!strcmp(iconf->if_type, "bridge") || !strcmp(iconf->if_type, "vlan"))
-		{
-			LOGN("Setting up dhsnif for %s", piface->if_base->inet.in_ifname);
+		netifd_inet_config_set(piface);
+		netifd_inet_config_apply(piface);
+	} else if (iconf->vlan_id_exists && iconf->vlan_id > 2) {
+		if (vlan_count < DHCP_SNIFF_MAX_VLAN && !strstr(iconf->if_name,"lan_")) {
+			piface = netifd_iface_new(iconf->if_name, iconf->if_type);
+			if (!piface) {
+				LOG(ERR, "netifd_add_inet_conf: %s: Unable to create interface.", iconf->if_name);
+				return;
+			}
 			netifd_inet_config_set(piface);
 			netifd_inet_config_apply(piface);
+			vlan_count++;
 		}
 	}
 
-	return piface;
+	return;
 }
 
 void netifd_del_inet_conf(struct schema_Wifi_Inet_Config *old_rec)
 {
 	struct netifd_iface *piface = NULL;
 
 	piface = netifd_iface_get_by_name(old_rec->if_name);
-	if (piface == NULL)
-	{
-		LOG(ERR, "netifd_del_inet_conf: Unable to delete non-existent interface %s.",
-				old_rec->if_name);
-	}
 
-	if (piface != NULL && !netifd_iface_del(piface))
-			{
+	if (!piface)
+		return;
+
+	if (netifd_iface_del(piface)) {
+		if (old_rec->vlan_id_exists && old_rec->vlan_id > 2)
+			vlan_count--;
+	} else {
 		LOG(ERR, "netifd_del_inet_conf: Error during destruction of interface %s.",
 				old_rec->if_name);
 	}

feeds/wlan-ap/opensync/src/platform/openwrt/src/netifd/src/inet_iface.c

@@ -24,8 +24,6 @@ struct netifd_iface *netifd_iface_get_by_name(char *_ifname)
 	if (piface != NULL)
 		return piface;
 
-	LOG(ERR, "netifd_iface_get_by_name: Couldn't find the interface(%s)", ifname);
-
 	return NULL;
 }
 
@@ -102,7 +100,7 @@ inet_base_t *netifd_iface_new_inet(const char *ifname, const char *iftype)
 		goto error;
 	}
 	memset(self, 0, sizeof(inet_base_t));
-	if((!strcmp(ifname, "wan") && !strcmp(iftype,"bridge")) || (!strcmp(ifname, "lan") && !strcmp(iftype,"bridge"))) {
+	if(!strcmp(iftype,"bridge")) {
 		snprintf(self->inet.in_ifname, sizeof(self->inet.in_ifname), "br-%s", ifname);
 	} else if (!strcmp(iftype,"vlan")) {
 		char name[15]= {};

feeds/wlan-ap/opensync/src/platform/openwrt/src/netifd/src/wifi_inet_config.c

@@ -368,16 +368,14 @@ static void callback_Wifi_Inet_Config(ovsdb_update_monitor_t *mon,
 			       struct schema_Wifi_Inet_Config *old_rec,
 			       struct schema_Wifi_Inet_Config *iconf)
 {
-	struct netifd_iface *piface = NULL;
-
 	switch (mon->mon_type) {
 	case OVSDB_UPDATE_NEW:
 		wifi_inet_conf_add(iconf);
-		piface = netifd_add_inet_conf(iconf);
+		netifd_add_inet_conf(iconf);
 		break;
 	case OVSDB_UPDATE_MODIFY:
 		wifi_inet_conf_add(iconf);
-		piface = netifd_modify_inet_conf(iconf);
+		netifd_modify_inet_conf(iconf);
 		break;
 	case OVSDB_UPDATE_DEL:
 		wifi_inet_conf_del(old_rec);
@@ -387,12 +385,6 @@ static void callback_Wifi_Inet_Config(ovsdb_update_monitor_t *mon,
 		LOG(ERR, "Invalid Wifi_Inet_Config mon_type(%d)", mon->mon_type);
 	}
 
-	if(!piface) {
-		LOG(ERR, "callback_Wifi_Inet_Config: Couldn't get the netifd interface(%s)",
-				iconf->if_name);
-		return;
-	}
-
 	return;
 }