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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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958501163d
This feature is defined in IEEE Std 802.11-2012, 10.23.13. It allows the AP devices to keep track of the hardware-address-to-IP-address mapping of the mobile devices within the WLAN network. The AP will learn this mapping via observing DHCP, ARP, and NS/NA frames. When a request for such information is made (i.e. ARP request, Neighbor Solicitation), the AP will respond on behalf of the associated mobile device. In the process of doing so, the AP will drop the multicast request frame that was intended to go out to the wireless medium. It was recommended at the LKS workshop to do this implementation in the bridge layer. vxlan.c is already doing something very similar. The DHCP snooping code will be added to the userspace application (hostapd) per the recommendation. This RFC commit is only for IPv4. A similar approach in the bridge layer will be taken for IPv6 as well. Signed-off-by: Kyeyoon Park <kyeyoonp@codeaurora.org> Signed-off-by: David S. Miller <davem@davemloft.net>
288 lines
6.5 KiB
C
288 lines
6.5 KiB
C
/*
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* Forwarding decision
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* Linux ethernet bridge
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*
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* Authors:
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* Lennert Buytenhek <buytenh@gnu.org>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <linux/kernel.h>
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#include <linux/netdevice.h>
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#include <linux/netpoll.h>
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#include <linux/skbuff.h>
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#include <linux/if_vlan.h>
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#include <linux/netfilter_bridge.h>
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#include "br_private.h"
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static int deliver_clone(const struct net_bridge_port *prev,
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struct sk_buff *skb,
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void (*__packet_hook)(const struct net_bridge_port *p,
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struct sk_buff *skb));
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/* Don't forward packets to originating port or forwarding disabled */
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static inline int should_deliver(const struct net_bridge_port *p,
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const struct sk_buff *skb)
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{
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return ((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
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br_allowed_egress(p->br, nbp_get_vlan_info(p), skb) &&
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p->state == BR_STATE_FORWARDING;
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}
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int br_dev_queue_push_xmit(struct sk_buff *skb)
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{
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/* ip_fragment doesn't copy the MAC header */
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if (nf_bridge_maybe_copy_header(skb) ||
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!is_skb_forwardable(skb->dev, skb)) {
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kfree_skb(skb);
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} else {
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skb_push(skb, ETH_HLEN);
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br_drop_fake_rtable(skb);
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dev_queue_xmit(skb);
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
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int br_forward_finish(struct sk_buff *skb)
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{
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return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
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br_dev_queue_push_xmit);
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}
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EXPORT_SYMBOL_GPL(br_forward_finish);
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static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
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{
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skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
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if (!skb)
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return;
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skb->dev = to->dev;
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if (unlikely(netpoll_tx_running(to->br->dev))) {
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if (!is_skb_forwardable(skb->dev, skb))
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kfree_skb(skb);
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else {
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skb_push(skb, ETH_HLEN);
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br_netpoll_send_skb(to, skb);
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}
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return;
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}
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NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
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br_forward_finish);
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}
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static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
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{
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struct net_device *indev;
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if (skb_warn_if_lro(skb)) {
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kfree_skb(skb);
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return;
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}
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skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
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if (!skb)
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return;
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indev = skb->dev;
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skb->dev = to->dev;
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skb_forward_csum(skb);
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NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
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br_forward_finish);
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}
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/* called with rcu_read_lock */
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void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
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{
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if (to && should_deliver(to, skb)) {
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__br_deliver(to, skb);
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return;
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}
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kfree_skb(skb);
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}
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/* called with rcu_read_lock */
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void br_forward(const struct net_bridge_port *to, struct sk_buff *skb, struct sk_buff *skb0)
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{
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if (should_deliver(to, skb)) {
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if (skb0)
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deliver_clone(to, skb, __br_forward);
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else
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__br_forward(to, skb);
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return;
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}
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if (!skb0)
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kfree_skb(skb);
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}
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static int deliver_clone(const struct net_bridge_port *prev,
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struct sk_buff *skb,
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void (*__packet_hook)(const struct net_bridge_port *p,
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struct sk_buff *skb))
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{
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struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
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skb = skb_clone(skb, GFP_ATOMIC);
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if (!skb) {
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dev->stats.tx_dropped++;
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return -ENOMEM;
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}
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__packet_hook(prev, skb);
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return 0;
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}
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static struct net_bridge_port *maybe_deliver(
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struct net_bridge_port *prev, struct net_bridge_port *p,
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struct sk_buff *skb,
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void (*__packet_hook)(const struct net_bridge_port *p,
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struct sk_buff *skb))
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{
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int err;
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if (!should_deliver(p, skb))
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return prev;
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if (!prev)
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goto out;
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err = deliver_clone(prev, skb, __packet_hook);
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if (err)
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return ERR_PTR(err);
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out:
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return p;
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}
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/* called under bridge lock */
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static void br_flood(struct net_bridge *br, struct sk_buff *skb,
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struct sk_buff *skb0,
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void (*__packet_hook)(const struct net_bridge_port *p,
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struct sk_buff *skb),
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bool unicast)
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{
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struct net_bridge_port *p;
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struct net_bridge_port *prev;
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prev = NULL;
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list_for_each_entry_rcu(p, &br->port_list, list) {
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/* Do not flood unicast traffic to ports that turn it off */
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if (unicast && !(p->flags & BR_FLOOD))
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continue;
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/* Do not flood to ports that enable proxy ARP */
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if (p->flags & BR_PROXYARP)
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continue;
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prev = maybe_deliver(prev, p, skb, __packet_hook);
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if (IS_ERR(prev))
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goto out;
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}
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if (!prev)
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goto out;
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if (skb0)
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deliver_clone(prev, skb, __packet_hook);
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else
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__packet_hook(prev, skb);
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return;
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out:
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if (!skb0)
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kfree_skb(skb);
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}
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/* called with rcu_read_lock */
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void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, bool unicast)
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{
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br_flood(br, skb, NULL, __br_deliver, unicast);
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}
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/* called under bridge lock */
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void br_flood_forward(struct net_bridge *br, struct sk_buff *skb,
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struct sk_buff *skb2, bool unicast)
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{
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br_flood(br, skb, skb2, __br_forward, unicast);
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}
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#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
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/* called with rcu_read_lock */
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static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
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struct sk_buff *skb, struct sk_buff *skb0,
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void (*__packet_hook)(
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const struct net_bridge_port *p,
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struct sk_buff *skb))
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{
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struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
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struct net_bridge *br = netdev_priv(dev);
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struct net_bridge_port *prev = NULL;
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struct net_bridge_port_group *p;
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struct hlist_node *rp;
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rp = rcu_dereference(hlist_first_rcu(&br->router_list));
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p = mdst ? rcu_dereference(mdst->ports) : NULL;
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while (p || rp) {
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struct net_bridge_port *port, *lport, *rport;
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lport = p ? p->port : NULL;
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rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
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NULL;
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port = (unsigned long)lport > (unsigned long)rport ?
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lport : rport;
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prev = maybe_deliver(prev, port, skb, __packet_hook);
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if (IS_ERR(prev))
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goto out;
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if ((unsigned long)lport >= (unsigned long)port)
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p = rcu_dereference(p->next);
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if ((unsigned long)rport >= (unsigned long)port)
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rp = rcu_dereference(hlist_next_rcu(rp));
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}
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if (!prev)
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goto out;
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if (skb0)
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deliver_clone(prev, skb, __packet_hook);
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else
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__packet_hook(prev, skb);
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return;
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out:
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if (!skb0)
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kfree_skb(skb);
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}
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/* called with rcu_read_lock */
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void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
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struct sk_buff *skb)
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{
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br_multicast_flood(mdst, skb, NULL, __br_deliver);
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}
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/* called with rcu_read_lock */
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void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
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struct sk_buff *skb, struct sk_buff *skb2)
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{
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br_multicast_flood(mdst, skb, skb2, __br_forward);
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}
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#endif
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