![Herbert Xu](/assets/img/avatar_default.png)
When the packet is delivered to the local bridge device we may end up cloning it unnecessarily if no bridge port can receive the packet in br_flood. This patch avoids this by moving the skb_clone into br_flood. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
170 lines
4.1 KiB
C
170 lines
4.1 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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* 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 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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brdev->stats.rx_packets++;
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brdev->stats.rx_bytes += skb->len;
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indev = skb->dev;
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skb->dev = brdev;
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return 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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struct sk_buff *skb2;
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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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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_multicast_ether_addr(dest)) {
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br->dev->stats.multicast++;
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skb2 = skb;
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} else if ((dst = __br_fdb_get(br, dest)) && 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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br_forward(dst->dst, skb);
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else
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br_flood_forward(br, skb, skb2);
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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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/* 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)
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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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__be16 *a = (__be16 *)dest;
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static const __be16 *b = (const __be16 *)br_group_address;
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static const __be16 m = cpu_to_be16(0xfff0);
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return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0;
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}
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/*
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* Called via br_handle_frame_hook.
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* Return NULL if skb is handled
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* note: already called with rcu_read_lock (preempt_disabled)
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*/
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struct sk_buff *br_handle_frame(struct net_bridge_port *p, 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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int (*rhook)(struct sk_buff *skb);
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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 NULL;
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if (unlikely(is_link_local(dest))) {
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/* Pause frames shouldn't be passed up by driver anyway */
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if (skb->protocol == htons(ETH_P_PAUSE))
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goto drop;
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/* If STP is turned off, then forward */
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if (p->br->stp_enabled == BR_NO_STP && dest[5] == 0)
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goto forward;
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if (NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
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NULL, br_handle_local_finish))
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return NULL; /* frame consumed by filter */
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else
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return skb; /* continue processing */
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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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rhook = rcu_dereference(br_should_route_hook);
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if (rhook != NULL) {
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if (rhook(skb))
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return skb;
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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 (!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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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 NULL;
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}
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