bridge: Extend Proxy ARP design to allow optional rules for Wi-Fi

This extends the design in commit 958501163ddd ("bridge: Add support for
IEEE 802.11 Proxy ARP") with optional set of rules that are needed to
meet the IEEE 802.11 and Hotspot 2.0 requirements for ProxyARP. The
previously added BR_PROXYARP behavior is left as-is and a new
BR_PROXYARP_WIFI alternative is added so that this behavior can be
configured from user space when required.

In addition, this enables proxyarp functionality for unicast ARP
requests for both BR_PROXYARP and BR_PROXYARP_WIFI since it is possible
to use unicast as well as broadcast for these frames.

The key differences in functionality:

BR_PROXYARP:
- uses the flag on the bridge port on which the request frame was
  received to determine whether to reply
- block bridge port flooding completely on ports that enable proxy ARP

BR_PROXYARP_WIFI:
- uses the flag on the bridge port to which the target device of the
  request belongs
- block bridge port flooding selectively based on whether the proxyarp
  functionality replied

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
index a57bca2..dad8b00 100644 (file)
--- a/include/linux/if_bridge.h
+++ b/include/linux/if_bridge.h
@@ -44,6 +44,7 @@ struct br_ip_list {
 #define BR_PROMISC             BIT(7)
 #define BR_PROXYARP            BIT(8)
 #define BR_LEARNING_SYNC       BIT(9)
+#define BR_PROXYARP_WIFI       BIT(10)
 
 extern void brioctl_set(int (*ioctl_hook)(struct net *, unsigned int, void __user *));
 

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index dfd0bb2..756436e 100644 (file)
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -247,6 +247,7 @@ enum {
        IFLA_BRPORT_UNICAST_FLOOD, /* flood unicast traffic */
        IFLA_BRPORT_PROXYARP,   /* proxy ARP */
        IFLA_BRPORT_LEARNING_SYNC, /* mac learning sync from device */
+       IFLA_BRPORT_PROXYARP_WIFI, /* proxy ARP for Wi-Fi */
        __IFLA_BRPORT_MAX
 };
 #define IFLA_BRPORT_MAX (__IFLA_BRPORT_MAX - 1)

diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index f96933a..1238fab 100644 (file)
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -188,6 +188,9 @@ static void br_flood(struct net_bridge *br, struct sk_buff *skb,
                /* Do not flood to ports that enable proxy ARP */
                if (p->flags & BR_PROXYARP)
                        continue;
+               if ((p->flags & BR_PROXYARP_WIFI) &&
+                   BR_INPUT_SKB_CB(skb)->proxyarp_replied)
+                       continue;
 
                prev = maybe_deliver(prev, p, skb, __packet_hook);
                if (IS_ERR(prev))

diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index e2aa7be..052c5eb 100644 (file)
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -60,7 +60,7 @@ static int br_pass_frame_up(struct sk_buff *skb)
 }
 
 static void br_do_proxy_arp(struct sk_buff *skb, struct net_bridge *br,
-                           u16 vid)
+                           u16 vid, struct net_bridge_port *p)
 {
        struct net_device *dev = br->dev;
        struct neighbour *n;
@@ -68,6 +68,8 @@ static void br_do_proxy_arp(struct sk_buff *skb, struct net_bridge *br,
        u8 *arpptr, *sha;
        __be32 sip, tip;
 
+       BR_INPUT_SKB_CB(skb)->proxyarp_replied = false;
+
        if (dev->flags & IFF_NOARP)
                return;
 
@@ -105,9 +107,12 @@ static void br_do_proxy_arp(struct sk_buff *skb, struct net_bridge *br,
                }
 
                f = __br_fdb_get(br, n->ha, vid);
-               if (f)
+               if (f && ((p->flags & BR_PROXYARP) ||
+                         (f->dst && (f->dst->flags & BR_PROXYARP_WIFI)))) {
                        arp_send(ARPOP_REPLY, ETH_P_ARP, sip, skb->dev, tip,
                                 sha, n->ha, sha);
+                       BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;
+               }
 
                neigh_release(n);
        }
@@ -153,12 +158,10 @@ int br_handle_frame_finish(struct sk_buff *skb)
 
        dst = NULL;
 
-       if (is_broadcast_ether_addr(dest)) {
-               if (IS_ENABLED(CONFIG_INET) &&
-                   p->flags & BR_PROXYARP &&
-                   skb->protocol == htons(ETH_P_ARP))
-                       br_do_proxy_arp(skb, br, vid);
+       if (IS_ENABLED(CONFIG_INET) && skb->protocol == htons(ETH_P_ARP))
+               br_do_proxy_arp(skb, br, vid, p);
 
+       if (is_broadcast_ether_addr(dest)) {
                skb2 = skb;
                unicast = false;
        } else if (is_multicast_ether_addr(dest)) {

diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index c720839..8bc6b67 100644 (file)
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -143,7 +143,9 @@ static int br_port_fill_attrs(struct sk_buff *skb,
            nla_put_u8(skb, IFLA_BRPORT_FAST_LEAVE, !!(p->flags & BR_MULTICAST_FAST_LEAVE)) ||
            nla_put_u8(skb, IFLA_BRPORT_LEARNING, !!(p->flags & BR_LEARNING)) ||
            nla_put_u8(skb, IFLA_BRPORT_UNICAST_FLOOD, !!(p->flags & BR_FLOOD)) ||
-           nla_put_u8(skb, IFLA_BRPORT_PROXYARP, !!(p->flags & BR_PROXYARP)))
+           nla_put_u8(skb, IFLA_BRPORT_PROXYARP, !!(p->flags & BR_PROXYARP)) ||
+           nla_put_u8(skb, IFLA_BRPORT_PROXYARP_WIFI,
+                      !!(p->flags & BR_PROXYARP_WIFI)))
                return -EMSGSIZE;
 
        return 0;
@@ -553,6 +555,7 @@ static int br_setport(struct net_bridge_port *p, struct nlattr *tb[])
        br_set_port_flag(p, tb, IFLA_BRPORT_LEARNING, BR_LEARNING);
        br_set_port_flag(p, tb, IFLA_BRPORT_UNICAST_FLOOD, BR_FLOOD);
        br_set_port_flag(p, tb, IFLA_BRPORT_PROXYARP, BR_PROXYARP);
+       br_set_port_flag(p, tb, IFLA_BRPORT_PROXYARP_WIFI, BR_PROXYARP_WIFI);
 
        if (tb[IFLA_BRPORT_COST]) {
                err = br_stp_set_path_cost(p, nla_get_u32(tb[IFLA_BRPORT_COST]));

diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index de09199..c32e279 100644 (file)
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -305,6 +305,7 @@ struct br_input_skb_cb {
 #endif
 
        u16 frag_max_size;
+       bool proxyarp_replied;
 
 #ifdef CONFIG_BRIDGE_VLAN_FILTERING
        bool vlan_filtered;

diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c
index 2de5d91..4905845 100644 (file)
--- a/net/bridge/br_sysfs_if.c
+++ b/net/bridge/br_sysfs_if.c
@@ -171,6 +171,7 @@ BRPORT_ATTR_FLAG(root_block, BR_ROOT_BLOCK);
 BRPORT_ATTR_FLAG(learning, BR_LEARNING);
 BRPORT_ATTR_FLAG(unicast_flood, BR_FLOOD);
 BRPORT_ATTR_FLAG(proxyarp, BR_PROXYARP);
+BRPORT_ATTR_FLAG(proxyarp_wifi, BR_PROXYARP_WIFI);
 
 #ifdef CONFIG_BRIDGE_IGMP_SNOOPING
 static ssize_t show_multicast_router(struct net_bridge_port *p, char *buf)
@@ -215,6 +216,7 @@ static const struct brport_attribute *brport_attrs[] = {
        &brport_attr_multicast_fast_leave,
 #endif
        &brport_attr_proxyarp,
+       &brport_attr_proxyarp_wifi,
        NULL
 };