batman-adv: refactoring gateway handling code

Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Acked-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Sven Eckelmann <sven@narfation.org>

diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c
index 619fb73..9373a14 100644 (file)
--- a/net/batman-adv/gateway_client.c
+++ b/net/batman-adv/gateway_client.c
@@ -25,6 +25,7 @@
 #include "gateway_common.h"
 #include "hard-interface.h"
 #include "originator.h"
+#include "translation-table.h"
 #include "routing.h"
 #include <linux/ip.h>
 #include <linux/ipv6.h>
@@ -572,108 +573,142 @@ out:
        return ret;
 }
 
-int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb,
-                struct orig_node *old_gw)
+bool gw_is_dhcp_target(struct sk_buff *skb, unsigned int *header_len)
 {
        struct ethhdr *ethhdr;
        struct iphdr *iphdr;
        struct ipv6hdr *ipv6hdr;
        struct udphdr *udphdr;
-       struct gw_node *curr_gw;
-       struct neigh_node *neigh_curr = NULL, *neigh_old = NULL;
-       unsigned int header_len = 0;
-       int ret = 1;
-
-       if (atomic_read(&bat_priv->gw_mode) == GW_MODE_OFF)
-               return 0;
 
        /* check for ethernet header */
-       if (!pskb_may_pull(skb, header_len + ETH_HLEN))
-               return 0;
+       if (!pskb_may_pull(skb, *header_len + ETH_HLEN))
+               return false;
        ethhdr = (struct ethhdr *)skb->data;
-       header_len += ETH_HLEN;
+       *header_len += ETH_HLEN;
 
        /* check for initial vlan header */
        if (ntohs(ethhdr->h_proto) == ETH_P_8021Q) {
-               if (!pskb_may_pull(skb, header_len + VLAN_HLEN))
-                       return 0;
+               if (!pskb_may_pull(skb, *header_len + VLAN_HLEN))
+                       return false;
                ethhdr = (struct ethhdr *)(skb->data + VLAN_HLEN);
-               header_len += VLAN_HLEN;
+               *header_len += VLAN_HLEN;
        }
 
        /* check for ip header */
        switch (ntohs(ethhdr->h_proto)) {
        case ETH_P_IP:
-               if (!pskb_may_pull(skb, header_len + sizeof(*iphdr)))
-                       return 0;
-               iphdr = (struct iphdr *)(skb->data + header_len);
-               header_len += iphdr->ihl * 4;
+               if (!pskb_may_pull(skb, *header_len + sizeof(*iphdr)))
+                       return false;
+               iphdr = (struct iphdr *)(skb->data + *header_len);
+               *header_len += iphdr->ihl * 4;
 
                /* check for udp header */
                if (iphdr->protocol != IPPROTO_UDP)
-                       return 0;
+                       return false;
 
                break;
        case ETH_P_IPV6:
-               if (!pskb_may_pull(skb, header_len + sizeof(*ipv6hdr)))
-                       return 0;
-               ipv6hdr = (struct ipv6hdr *)(skb->data + header_len);
-               header_len += sizeof(*ipv6hdr);
+               if (!pskb_may_pull(skb, *header_len + sizeof(*ipv6hdr)))
+                       return false;
+               ipv6hdr = (struct ipv6hdr *)(skb->data + *header_len);
+               *header_len += sizeof(*ipv6hdr);
 
                /* check for udp header */
                if (ipv6hdr->nexthdr != IPPROTO_UDP)
-                       return 0;
+                       return false;
 
                break;
        default:
-               return 0;
+               return false;
        }
 
-       if (!pskb_may_pull(skb, header_len + sizeof(*udphdr)))
-               return 0;
-       udphdr = (struct udphdr *)(skb->data + header_len);
-       header_len += sizeof(*udphdr);
+       if (!pskb_may_pull(skb, *header_len + sizeof(*udphdr)))
+               return false;
+       udphdr = (struct udphdr *)(skb->data + *header_len);
+       *header_len += sizeof(*udphdr);
 
        /* check for bootp port */
        if ((ntohs(ethhdr->h_proto) == ETH_P_IP) &&
             (ntohs(udphdr->dest) != 67))
-               return 0;
+               return false;
 
        if ((ntohs(ethhdr->h_proto) == ETH_P_IPV6) &&
            (ntohs(udphdr->dest) != 547))
-               return 0;
+               return false;
 
-       if (atomic_read(&bat_priv->gw_mode) == GW_MODE_SERVER)
-               return -1;
+       return true;
+}
 
-       curr_gw = gw_get_selected_gw_node(bat_priv);
-       if (!curr_gw)
-               return 0;
-
-       /* If old_gw != NULL then this packet is unicast.
-        * So, at this point we have to check the message type: if it is a
-        * DHCPREQUEST we have to decide whether to drop it or not */
-       if (old_gw && curr_gw->orig_node != old_gw) {
-               if (is_type_dhcprequest(skb, header_len)) {
-                       /* If the dhcp packet has been sent to a different gw,
-                        * we have to evaluate whether the old gw is still
-                        * reliable enough */
-                       neigh_curr = find_router(bat_priv, curr_gw->orig_node,
-                                                NULL);
-                       neigh_old = find_router(bat_priv, old_gw, NULL);
-                       if (!neigh_curr || !neigh_old)
-                               goto free_neigh;
-                       if (neigh_curr->tq_avg - neigh_old->tq_avg <
-                                                               GW_THRESHOLD)
-                               ret = -1;
-               }
+bool gw_out_of_range(struct bat_priv *bat_priv,
+                    struct sk_buff *skb, struct ethhdr *ethhdr)
+{
+       struct neigh_node *neigh_curr = NULL, *neigh_old = NULL;
+       struct orig_node *orig_dst_node = NULL;
+       struct gw_node *curr_gw = NULL;
+       bool ret, out_of_range = false;
+       unsigned int header_len = 0;
+       uint8_t curr_tq_avg;
+
+       ret = gw_is_dhcp_target(skb, &header_len);
+       if (!ret)
+               goto out;
+
+       orig_dst_node = transtable_search(bat_priv, ethhdr->h_source,
+                                         ethhdr->h_dest);
+       if (!orig_dst_node)
+               goto out;
+
+       if (!orig_dst_node->gw_flags)
+               goto out;
+
+       ret = is_type_dhcprequest(skb, header_len);
+       if (!ret)
+               goto out;
+
+       switch (atomic_read(&bat_priv->gw_mode)) {
+       case GW_MODE_SERVER:
+               /* If we are a GW then we are our best GW. We can artificially
+                * set the tq towards ourself as the maximum value */
+               curr_tq_avg = TQ_MAX_VALUE;
+               break;
+       case GW_MODE_CLIENT:
+               curr_gw = gw_get_selected_gw_node(bat_priv);
+               if (!curr_gw)
+                       goto out;
+
+               /* packet is going to our gateway */
+               if (curr_gw->orig_node == orig_dst_node)
+                       goto out;
+
+               /* If the dhcp packet has been sent to a different gw,
+                * we have to evaluate whether the old gw is still
+                * reliable enough */
+               neigh_curr = find_router(bat_priv, curr_gw->orig_node, NULL);
+               if (!neigh_curr)
+                       goto out;
+
+               curr_tq_avg = neigh_curr->tq_avg;
+               break;
+       case GW_MODE_OFF:
+       default:
+               goto out;
        }
-free_neigh:
+
+       neigh_old = find_router(bat_priv, orig_dst_node, NULL);
+       if (!!neigh_old)
+               goto out;
+
+       if (curr_tq_avg - neigh_old->tq_avg > GW_THRESHOLD)
+               out_of_range = true;
+
+out:
+       if (orig_dst_node)
+               orig_node_free_ref(orig_dst_node);
+       if (curr_gw)
+               gw_node_free_ref(curr_gw);
        if (neigh_old)
                neigh_node_free_ref(neigh_old);
        if (neigh_curr)
                neigh_node_free_ref(neigh_curr);
-       if (curr_gw)
-               gw_node_free_ref(curr_gw);
-       return ret;
+       return out_of_range;
 }

diff --git a/net/batman-adv/gateway_client.h b/net/batman-adv/gateway_client.h
index b9b983c..e1edba0 100644 (file)
--- a/net/batman-adv/gateway_client.h
+++ b/net/batman-adv/gateway_client.h
@@ -31,7 +31,8 @@ void gw_node_update(struct bat_priv *bat_priv,
 void gw_node_delete(struct bat_priv *bat_priv, struct orig_node *orig_node);
 void gw_node_purge(struct bat_priv *bat_priv);
 int gw_client_seq_print_text(struct seq_file *seq, void *offset);
-int gw_is_target(struct bat_priv *bat_priv, struct sk_buff *skb,
-                struct orig_node *old_gw);
+bool gw_is_dhcp_target(struct sk_buff *skb, unsigned int *header_len);
+bool gw_out_of_range(struct bat_priv *bat_priv,
+                    struct sk_buff *skb, struct ethhdr *ethhdr);
 
 #endif /* _NET_BATMAN_ADV_GATEWAY_CLIENT_H_ */

diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index f9cc957..45297c8 100644 (file)
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -563,10 +563,10 @@ static int interface_tx(struct sk_buff *skb, struct net_device *soft_iface)
        struct bcast_packet *bcast_packet;
        struct vlan_ethhdr *vhdr;
        struct softif_neigh *curr_softif_neigh = NULL;
-       struct orig_node *orig_node = NULL;
+       unsigned int header_len = 0;
        int data_len = skb->len, ret;
        short vid = -1;
-       bool do_bcast;
+       bool do_bcast = false;
 
        if (atomic_read(&bat_priv->mesh_state) != MESH_ACTIVE)
                goto dropped;
@@ -598,17 +598,28 @@ static int interface_tx(struct sk_buff *skb, struct net_device *soft_iface)
        /* Register the client MAC in the transtable */
        tt_local_add(soft_iface, ethhdr->h_source, skb->skb_iif);
 
-       orig_node = transtable_search(bat_priv, ethhdr->h_source,
-                                     ethhdr->h_dest);
-       do_bcast = is_multicast_ether_addr(ethhdr->h_dest);
-       if (do_bcast || (orig_node && orig_node->gw_flags)) {
-               ret = gw_is_target(bat_priv, skb, orig_node);
+       if (is_multicast_ether_addr(ethhdr->h_dest)) {
+               do_bcast = true;
 
-               if (ret < 0)
-                       goto dropped;
-
-               if (ret)
-                       do_bcast = false;
+               switch (atomic_read(&bat_priv->gw_mode)) {
+               case GW_MODE_SERVER:
+                       /* gateway servers should not send dhcp
+                        * requests into the mesh */
+                       ret = gw_is_dhcp_target(skb, &header_len);
+                       if (ret)
+                               goto dropped;
+                       break;
+               case GW_MODE_CLIENT:
+                       /* gateway clients should send dhcp requests
+                        * via unicast to their gateway */
+                       ret = gw_is_dhcp_target(skb, &header_len);
+                       if (ret)
+                               do_bcast = false;
+                       break;
+               case GW_MODE_OFF:
+               default:
+                       break;
+               }
        }
 
        /* ethernet packet should be broadcasted */
@@ -644,6 +655,12 @@ static int interface_tx(struct sk_buff *skb, struct net_device *soft_iface)
 
        /* unicast packet */
        } else {
+               if (atomic_read(&bat_priv->gw_mode) != GW_MODE_OFF) {
+                       ret = gw_out_of_range(bat_priv, skb, ethhdr);
+                       if (ret)
+                               goto dropped;
+               }
+
                ret = unicast_send_skb(skb, bat_priv);
                if (ret != 0)
                        goto dropped_freed;
@@ -662,8 +679,6 @@ end:
                softif_neigh_free_ref(curr_softif_neigh);
        if (primary_if)
                hardif_free_ref(primary_if);
-       if (orig_node)
-               orig_node_free_ref(orig_node);
        return NETDEV_TX_OK;
 }