158 lines
3.7 KiB
C
158 lines
3.7 KiB
C
/*
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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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* $Id: br_input.c,v 1.10 2001/12/24 04:50:20 davem Exp $
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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/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 "br_private.h"
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/* Bridge group multicast address 802.1d (pg 51). */
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const u8 br_group_address[ETH_ALEN] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
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static void br_pass_frame_up(struct net_bridge *br, struct sk_buff *skb)
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{
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struct net_device *indev;
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br->statistics.rx_packets++;
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br->statistics.rx_bytes += skb->len;
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indev = skb->dev;
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skb->dev = br->dev;
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NF_HOOK(PF_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 (preempt_disabled) */
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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 = rcu_dereference(skb->dev->br_port);
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struct net_bridge *br;
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struct net_bridge_fdb_entry *dst;
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int passedup = 0;
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if (!p || p->state == BR_STATE_DISABLED)
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goto drop;
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/* insert into forwarding database after filtering to avoid spoofing */
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br = p->br;
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br_fdb_update(br, p, eth_hdr(skb)->h_source);
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if (p->state == BR_STATE_LEARNING)
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goto drop;
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if (br->dev->flags & IFF_PROMISC) {
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struct sk_buff *skb2;
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skb2 = skb_clone(skb, GFP_ATOMIC);
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if (skb2 != NULL) {
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passedup = 1;
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br_pass_frame_up(br, skb2);
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}
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}
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if (is_multicast_ether_addr(dest)) {
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br->statistics.multicast++;
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br_flood_forward(br, skb, !passedup);
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if (!passedup)
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br_pass_frame_up(br, skb);
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goto out;
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}
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dst = __br_fdb_get(br, dest);
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if (dst != NULL && dst->is_local) {
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if (!passedup)
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br_pass_frame_up(br, skb);
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else
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kfree_skb(skb);
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goto out;
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}
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if (dst != NULL) {
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br_forward(dst->dst, skb);
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goto out;
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}
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br_flood_forward(br, skb, 0);
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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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/* note: already called with rcu_read_lock (preempt_disabled) */
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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 = rcu_dereference(skb->dev->br_port);
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if (p && p->state != BR_STATE_DISABLED)
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br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
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return 0; /* process further */
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}
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/* Does address match the link local multicast address.
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* 01:80:c2:00:00:0X
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*/
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static inline int is_link_local(const unsigned char *dest)
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{
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return memcmp(dest, br_group_address, 5) == 0 && (dest[5] & 0xf0) == 0;
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}
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/*
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* Called via br_handle_frame_hook.
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* Return 0 if *pskb should be processed furthur
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* 1 if *pskb is handled
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* note: already called with rcu_read_lock (preempt_disabled)
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*/
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int br_handle_frame(struct net_bridge_port *p, struct sk_buff **pskb)
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{
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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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if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
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goto err;
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if (unlikely(is_link_local(dest))) {
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skb->pkt_type = PACKET_HOST;
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return NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
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NULL, br_handle_local_finish) != 0;
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}
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if (p->state == BR_STATE_FORWARDING || p->state == BR_STATE_LEARNING) {
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if (br_should_route_hook) {
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if (br_should_route_hook(pskb))
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return 0;
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skb = *pskb;
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dest = eth_hdr(skb)->h_dest;
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}
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if (!compare_ether_addr(p->br->dev->dev_addr, dest))
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skb->pkt_type = PACKET_HOST;
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NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
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br_handle_frame_finish);
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return 1;
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}
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err:
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kfree_skb(skb);
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return 1;
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}
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