| /* |
| * Handle incoming frames |
| * Linux ethernet bridge |
| * |
| * Authors: |
| * Lennert Buytenhek <buytenh@gnu.org> |
| * |
| * $Id: br_input.c,v 1.10 2001/12/24 04:50:20 davem Exp $ |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/netdevice.h> |
| #include <linux/etherdevice.h> |
| #include <linux/netfilter_bridge.h> |
| #include "br_private.h" |
| |
| const unsigned char bridge_ula[6] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 }; |
| |
| static void br_pass_frame_up(struct net_bridge *br, struct sk_buff *skb) |
| { |
| struct net_device *indev; |
| |
| br->statistics.rx_packets++; |
| br->statistics.rx_bytes += skb->len; |
| |
| indev = skb->dev; |
| skb->dev = br->dev; |
| |
| NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL, |
| netif_receive_skb); |
| } |
| |
| /* note: already called with rcu_read_lock (preempt_disabled) */ |
| int br_handle_frame_finish(struct sk_buff *skb) |
| { |
| const unsigned char *dest = eth_hdr(skb)->h_dest; |
| struct net_bridge_port *p = rcu_dereference(skb->dev->br_port); |
| struct net_bridge *br; |
| struct net_bridge_fdb_entry *dst; |
| int passedup = 0; |
| |
| if (!p || p->state == BR_STATE_DISABLED) |
| goto drop; |
| |
| /* insert into forwarding database after filtering to avoid spoofing */ |
| br = p->br; |
| br_fdb_update(br, p, eth_hdr(skb)->h_source); |
| |
| if (p->state == BR_STATE_LEARNING) |
| goto drop; |
| |
| if (br->dev->flags & IFF_PROMISC) { |
| struct sk_buff *skb2; |
| |
| skb2 = skb_clone(skb, GFP_ATOMIC); |
| if (skb2 != NULL) { |
| passedup = 1; |
| br_pass_frame_up(br, skb2); |
| } |
| } |
| |
| if (is_multicast_ether_addr(dest)) { |
| br_flood_forward(br, skb, !passedup); |
| if (!passedup) |
| br_pass_frame_up(br, skb); |
| goto out; |
| } |
| |
| dst = __br_fdb_get(br, dest); |
| if (dst != NULL && dst->is_local) { |
| if (!passedup) |
| br_pass_frame_up(br, skb); |
| else |
| kfree_skb(skb); |
| goto out; |
| } |
| |
| if (dst != NULL) { |
| br_forward(dst->dst, skb); |
| goto out; |
| } |
| |
| br_flood_forward(br, skb, 0); |
| |
| out: |
| return 0; |
| drop: |
| kfree_skb(skb); |
| goto out; |
| } |
| |
| /* note: already called with rcu_read_lock (preempt_disabled) */ |
| static int br_handle_local_finish(struct sk_buff *skb) |
| { |
| struct net_bridge_port *p = rcu_dereference(skb->dev->br_port); |
| |
| if (p && p->state != BR_STATE_DISABLED) |
| br_fdb_update(p->br, p, eth_hdr(skb)->h_source); |
| |
| return 0; /* process further */ |
| } |
| |
| /* Does address match the link local multicast address. |
| * 01:80:c2:00:00:0X |
| */ |
| static inline int is_link_local(const unsigned char *dest) |
| { |
| return memcmp(dest, bridge_ula, 5) == 0 && (dest[5] & 0xf0) == 0; |
| } |
| |
| /* |
| * Called via br_handle_frame_hook. |
| * Return 0 if *pskb should be processed furthur |
| * 1 if *pskb is handled |
| * note: already called with rcu_read_lock (preempt_disabled) |
| */ |
| int br_handle_frame(struct net_bridge_port *p, struct sk_buff **pskb) |
| { |
| struct sk_buff *skb = *pskb; |
| const unsigned char *dest = eth_hdr(skb)->h_dest; |
| |
| if (p->state == BR_STATE_DISABLED) |
| goto err; |
| |
| if (!is_valid_ether_addr(eth_hdr(skb)->h_source)) |
| goto err; |
| |
| if (unlikely(is_link_local(dest))) { |
| skb->pkt_type = PACKET_HOST; |
| return NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev, |
| NULL, br_handle_local_finish) != 0; |
| } |
| |
| if (p->state == BR_STATE_FORWARDING || p->state == BR_STATE_LEARNING) { |
| if (br_should_route_hook) { |
| if (br_should_route_hook(pskb)) |
| return 0; |
| skb = *pskb; |
| dest = eth_hdr(skb)->h_dest; |
| } |
| |
| if (!compare_ether_addr(p->br->dev->dev_addr, dest)) |
| skb->pkt_type = PACKET_HOST; |
| |
| NF_HOOK(PF_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL, |
| br_handle_frame_finish); |
| return 1; |
| } |
| |
| err: |
| kfree_skb(skb); |
| return 1; |
| } |