255 lines
6.3 KiB
C
Executable File
255 lines
6.3 KiB
C
Executable File
/*
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* Handle incoming frames
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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/slab.h>
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#include <linux/kernel.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/netfilter_bridge.h>
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#include <linux/export.h>
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#include <linux/rculist.h>
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#include "br_private.h"
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#include "ecnt_br.h"
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/* Hook for brouter */
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br_should_route_hook_t __rcu *br_should_route_hook __read_mostly;
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EXPORT_SYMBOL(br_should_route_hook);
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static int br_pass_frame_up(struct sk_buff *skb)
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{
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struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
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struct net_bridge *br = netdev_priv(brdev);
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struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats);
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struct net_port_vlans *pv;
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u64_stats_update_begin(&brstats->syncp);
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brstats->rx_packets++;
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brstats->rx_bytes += skb->len;
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u64_stats_update_end(&brstats->syncp);
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/* Bridge is just like any other port. Make sure the
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* packet is allowed except in promisc modue when someone
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* may be running packet capture.
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*/
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pv = br_get_vlan_info(br);
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if (!(brdev->flags & IFF_PROMISC) &&
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!br_allowed_egress(br, pv, skb)) {
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kfree_skb(skb);
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return NET_RX_DROP;
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}
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indev = skb->dev;
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skb->dev = brdev;
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skb = br_handle_vlan(br, pv, skb);
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if (!skb)
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return NET_RX_DROP;
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return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL,
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netif_receive_skb);
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}
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/* note: already called with rcu_read_lock */
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int br_handle_frame_finish(struct sk_buff *skb)
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{
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const unsigned char *dest = eth_hdr(skb)->h_dest;
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struct net_bridge_port *p = br_port_get_rcu(skb->dev);
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struct net_bridge *br;
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struct net_bridge_fdb_entry *dst;
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struct net_bridge_mdb_entry *mdst;
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struct sk_buff *skb2;
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bool unicast = true;
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u16 vid = 0;
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#if defined(TCSUPPORT_RA_HWNAT)
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skb->bridge_flag = 0;
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#endif
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if (!p || p->state == BR_STATE_DISABLED)
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goto drop;
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if (!br_allowed_ingress(p->br, nbp_get_vlan_info(p), skb, &vid))
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goto out;
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/* insert into forwarding database after filtering to avoid spoofing */
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br = p->br;
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if (p->flags & BR_LEARNING)
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br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, false);
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if (!is_broadcast_ether_addr(dest) && is_multicast_ether_addr(dest) &&
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br_multicast_rcv(br, p, skb, vid))
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goto drop;
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if (p->state == BR_STATE_LEARNING)
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goto drop;
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BR_INPUT_SKB_CB(skb)->brdev = br->dev;
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/* The packet skb2 goes to the local host (NULL to skip). */
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skb2 = NULL;
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if (br->dev->flags & IFF_PROMISC)
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skb2 = skb;
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dst = NULL;
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if (is_broadcast_ether_addr(dest)) {
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skb2 = skb;
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unicast = false;
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} else if (is_multicast_ether_addr(dest)) {
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mdst = br_mdb_get(br, skb, vid);
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if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
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br_multicast_querier_exists(br, eth_hdr(skb))) {
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if ((mdst && mdst->mglist) ||
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br_multicast_is_router(br))
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skb2 = skb;
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br_multicast_forward(mdst, skb, skb2);
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skb = NULL;
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if (!skb2)
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goto out;
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} else
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skb2 = skb;
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unicast = false;
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br->dev->stats.multicast++;
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} else if ((dst = __br_fdb_get(br, dest, vid)) &&
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dst->is_local) {
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skb2 = skb;
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/* Do not forward the packet since it's local. */
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skb = NULL;
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}
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if (skb) {
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if (dst) {
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dst->used = jiffies;
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br_forward(dst->dst, skb, skb2);
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} else
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br_flood_forward(br, skb, skb2, unicast);
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}
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if (skb2)
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return br_pass_frame_up(skb2);
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out:
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return 0;
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drop:
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kfree_skb(skb);
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goto out;
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}
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EXPORT_SYMBOL_GPL(br_handle_frame_finish);
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/* note: already called with rcu_read_lock */
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static int br_handle_local_finish(struct sk_buff *skb)
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{
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struct net_bridge_port *p = br_port_get_rcu(skb->dev);
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u16 vid = 0;
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/* check if vlan is allowed, to avoid spoofing */
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if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid))
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br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false);
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return 0; /* process further */
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}
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/*
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* Return NULL if skb is handled
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* note: already called with rcu_read_lock
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*/
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rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
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{
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struct net_bridge_port *p;
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struct sk_buff *skb = *pskb;
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const unsigned char *dest = eth_hdr(skb)->h_dest;
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br_should_route_hook_t *rhook;
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if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
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return RX_HANDLER_PASS;
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if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
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goto drop;
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skb = skb_share_check(skb, GFP_ATOMIC);
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if (!skb)
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return RX_HANDLER_CONSUMED;
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p = br_port_get_rcu(skb->dev);
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if (unlikely(is_link_local_ether_addr(dest))) {
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u16 fwd_mask = p->br->group_fwd_mask_required;
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/*
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* See IEEE 802.1D Table 7-10 Reserved addresses
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*
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* Assignment Value
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* Bridge Group Address 01-80-C2-00-00-00
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* (MAC Control) 802.3 01-80-C2-00-00-01
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* (Link Aggregation) 802.3 01-80-C2-00-00-02
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* 802.1X PAE address 01-80-C2-00-00-03
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*
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* 802.1AB LLDP 01-80-C2-00-00-0E
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*
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* Others reserved for future standardization
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*/
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switch (dest[5]) {
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case 0x00: /* Bridge Group Address */
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/* If STP is turned off,
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then must forward to keep loop detection */
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if (p->br->stp_enabled == BR_NO_STP ||
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fwd_mask & (1u << dest[5]))
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goto forward;
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break;
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case 0x01: /* IEEE MAC (Pause) */
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goto drop;
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default:
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/* Allow selective forwarding for most other protocols */
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fwd_mask |= p->br->group_fwd_mask;
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if (fwd_mask & (1u << dest[5]))
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goto forward;
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}
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/* Deliver packet to local host only */
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if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
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NULL, br_handle_local_finish)) {
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return RX_HANDLER_CONSUMED; /* consumed by filter */
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} else {
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*pskb = skb;
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return RX_HANDLER_PASS; /* continue processing */
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}
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}
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forward:
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switch (p->state) {
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case BR_STATE_FORWARDING:
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ecnt_br_input_state_forward_inline_hook(skb);
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rhook = rcu_dereference(br_should_route_hook);
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if (rhook) {
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if ((*rhook)(skb)) {
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*pskb = skb;
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return RX_HANDLER_PASS;
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}
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dest = eth_hdr(skb)->h_dest;
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}
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/* fall through */
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case BR_STATE_LEARNING:
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if (ether_addr_equal(p->br->dev->dev_addr, dest))
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skb->pkt_type = PACKET_HOST;
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NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
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br_handle_frame_finish);
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break;
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default:
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drop:
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kfree_skb(skb);
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}
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return RX_HANDLER_CONSUMED;
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}
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