| /* |
| * 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" |
| |
| /* Bridge group multicast address 802.1d (pg 51). */ |
| const u8 br_group_address[ETH_ALEN] = { 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; |
| struct sk_buff *skb2; |
| |
| 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; |
| |
| /* The packet skb2 goes to the local host (NULL to skip). */ |
| skb2 = NULL; |
| |
| if (br->dev->flags & IFF_PROMISC) |
| skb2 = skb; |
| |
| dst = NULL; |
| |
| if (is_multicast_ether_addr(dest)) { |
| br->statistics.multicast++; |
| skb2 = skb; |
| } else if ((dst = __br_fdb_get(br, dest)) && dst->is_local) { |
| skb2 = skb; |
| /* Do not forward the packet since it's local. */ |
| skb = NULL; |
| } |
| |
| if (skb2 == skb) |
| skb2 = skb_clone(skb, GFP_ATOMIC); |
| |
| if (skb2) |
| br_pass_frame_up(br, skb2); |
| |
| if (skb) { |
| if (dst) |
| br_forward(dst->dst, skb); |
| else |
| br_flood_forward(br, skb); |
| } |
| |
| 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) |
| 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) |
| { |
| __be16 *a = (__be16 *)dest; |
| static const __be16 *b = (const __be16 *)br_group_address; |
| static const __be16 m = __constant_cpu_to_be16(0xfff0); |
| |
| return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0; |
| } |
| |
| /* |
| * Called via br_handle_frame_hook. |
| * Return NULL if skb is handled |
| * note: already called with rcu_read_lock (preempt_disabled) |
| */ |
| struct sk_buff *br_handle_frame(struct net_bridge_port *p, struct sk_buff *skb) |
| { |
| const unsigned char *dest = eth_hdr(skb)->h_dest; |
| |
| if (!is_valid_ether_addr(eth_hdr(skb)->h_source)) |
| goto drop; |
| |
| skb = skb_share_check(skb, GFP_ATOMIC); |
| if (!skb) |
| return NULL; |
| |
| if (unlikely(is_link_local(dest))) { |
| /* Pause frames shouldn't be passed up by driver anyway */ |
| if (skb->protocol == htons(ETH_P_PAUSE)) |
| goto drop; |
| |
| /* Process STP BPDU's through normal netif_receive_skb() path */ |
| if (p->br->stp_enabled != BR_NO_STP) { |
| if (NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev, |
| NULL, br_handle_local_finish)) |
| return NULL; |
| else |
| return skb; |
| } |
| } |
| |
| switch (p->state) { |
| case BR_STATE_FORWARDING: |
| |
| if (br_should_route_hook) { |
| if (br_should_route_hook(skb)) |
| return skb; |
| dest = eth_hdr(skb)->h_dest; |
| } |
| /* fall through */ |
| case BR_STATE_LEARNING: |
| 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); |
| break; |
| default: |
| drop: |
| kfree_skb(skb); |
| } |
| return NULL; |
| } |