286 lines
6.5 KiB
C
286 lines
6.5 KiB
C
/*
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* Forwarding decision
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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/err.h>
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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/netpoll.h>
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#include <linux/skbuff.h>
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#include <linux/if_vlan.h>
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#include <linux/netfilter_bridge.h>
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#include "br_private.h"
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static int deliver_clone(const struct net_bridge_port *prev,
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struct sk_buff *skb,
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void (*__packet_hook)(const struct net_bridge_port *p,
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struct sk_buff *skb));
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/* Don't forward packets to originating port or forwarding diasabled */
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static inline int should_deliver(const struct net_bridge_port *p,
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const struct sk_buff *skb)
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{
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return (((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
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br_allowed_egress(p->br, nbp_get_vlan_info(p), skb) &&
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p->state == BR_STATE_FORWARDING);
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}
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static inline unsigned int packet_length(const struct sk_buff *skb)
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{
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return skb->len - (skb->protocol == htons(ETH_P_8021Q) ? VLAN_HLEN : 0);
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}
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int br_dev_queue_push_xmit(struct sk_buff *skb)
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{
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/* ip_fragment doesn't copy the MAC header */
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if (nf_bridge_maybe_copy_header(skb) ||
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(packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))) {
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kfree_skb(skb);
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} else {
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skb_push(skb, ETH_HLEN);
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br_drop_fake_rtable(skb);
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dev_queue_xmit(skb);
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}
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return 0;
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}
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int br_forward_finish(struct sk_buff *skb)
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{
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return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING, skb, NULL, skb->dev,
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br_dev_queue_push_xmit);
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}
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static void __br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
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{
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skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
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if (!skb)
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return;
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skb->dev = to->dev;
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if (unlikely(netpoll_tx_running(to->br->dev))) {
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if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))
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kfree_skb(skb);
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else {
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skb_push(skb, ETH_HLEN);
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br_netpoll_send_skb(to, skb);
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}
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return;
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}
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NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev,
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br_forward_finish);
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}
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static void __br_forward(const struct net_bridge_port *to, struct sk_buff *skb)
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{
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struct net_device *indev;
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if (skb_warn_if_lro(skb)) {
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kfree_skb(skb);
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return;
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}
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skb = br_handle_vlan(to->br, nbp_get_vlan_info(to), skb);
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if (!skb)
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return;
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indev = skb->dev;
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skb->dev = to->dev;
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skb_forward_csum(skb);
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NF_HOOK(NFPROTO_BRIDGE, NF_BR_FORWARD, skb, indev, skb->dev,
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br_forward_finish);
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}
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/* called with rcu_read_lock */
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void br_deliver(const struct net_bridge_port *to, struct sk_buff *skb)
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{
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if (to && should_deliver(to, skb)) {
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__br_deliver(to, skb);
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return;
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}
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kfree_skb(skb);
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}
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/* called with rcu_read_lock */
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void br_forward(const struct net_bridge_port *to, struct sk_buff *skb, struct sk_buff *skb0)
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{
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if (should_deliver(to, skb)) {
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if (skb0)
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deliver_clone(to, skb, __br_forward);
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else
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__br_forward(to, skb);
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return;
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}
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if (!skb0)
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kfree_skb(skb);
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}
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static int deliver_clone(const struct net_bridge_port *prev,
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struct sk_buff *skb,
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void (*__packet_hook)(const struct net_bridge_port *p,
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struct sk_buff *skb))
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{
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struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
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skb = skb_clone(skb, GFP_ATOMIC);
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if (!skb) {
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dev->stats.tx_dropped++;
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return -ENOMEM;
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}
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__packet_hook(prev, skb);
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return 0;
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}
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static struct net_bridge_port *maybe_deliver(
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struct net_bridge_port *prev, struct net_bridge_port *p,
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struct sk_buff *skb,
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void (*__packet_hook)(const struct net_bridge_port *p,
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struct sk_buff *skb))
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{
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int err;
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if (!should_deliver(p, skb))
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return prev;
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if (!prev)
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goto out;
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err = deliver_clone(prev, skb, __packet_hook);
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if (err)
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return ERR_PTR(err);
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out:
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return p;
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}
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/* called under bridge lock */
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static void br_flood(struct net_bridge *br, struct sk_buff *skb,
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struct sk_buff *skb0,
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void (*__packet_hook)(const struct net_bridge_port *p,
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struct sk_buff *skb),
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bool unicast)
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{
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struct net_bridge_port *p;
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struct net_bridge_port *prev;
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prev = NULL;
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list_for_each_entry_rcu(p, &br->port_list, list) {
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/* Do not flood unicast traffic to ports that turn it off */
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if (unicast && !(p->flags & BR_FLOOD))
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continue;
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prev = maybe_deliver(prev, p, skb, __packet_hook);
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if (IS_ERR(prev))
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goto out;
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}
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if (!prev)
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goto out;
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if (skb0)
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deliver_clone(prev, skb, __packet_hook);
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else
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__packet_hook(prev, skb);
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return;
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out:
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if (!skb0)
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kfree_skb(skb);
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}
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/* called with rcu_read_lock */
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void br_flood_deliver(struct net_bridge *br, struct sk_buff *skb, bool unicast)
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{
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br_flood(br, skb, NULL, __br_deliver, unicast);
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}
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/* called under bridge lock */
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void br_flood_forward(struct net_bridge *br, struct sk_buff *skb,
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struct sk_buff *skb2, bool unicast)
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{
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br_flood(br, skb, skb2, __br_forward, unicast);
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}
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#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
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/* called with rcu_read_lock */
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static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
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struct sk_buff *skb, struct sk_buff *skb0,
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void (*__packet_hook)(
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const struct net_bridge_port *p,
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struct sk_buff *skb))
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{
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struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
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struct net_bridge *br = netdev_priv(dev);
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struct net_bridge_port *prev = NULL;
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struct net_bridge_port_group *p;
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struct hlist_node *rp;
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rp = rcu_dereference(hlist_first_rcu(&br->router_list));
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p = mdst ? rcu_dereference(mdst->ports) : NULL;
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while (p || rp) {
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struct net_bridge_port *port, *lport, *rport;
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lport = p ? p->port : NULL;
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rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
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NULL;
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port = (unsigned long)lport > (unsigned long)rport ?
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lport : rport;
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prev = maybe_deliver(prev, port, skb, __packet_hook);
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if (IS_ERR(prev))
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goto out;
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if ((unsigned long)lport >= (unsigned long)port)
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p = rcu_dereference(p->next);
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if ((unsigned long)rport >= (unsigned long)port)
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rp = rcu_dereference(hlist_next_rcu(rp));
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}
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if (!prev)
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goto out;
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if (skb0)
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deliver_clone(prev, skb, __packet_hook);
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else
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__packet_hook(prev, skb);
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return;
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out:
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if (!skb0)
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kfree_skb(skb);
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}
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/* called with rcu_read_lock */
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void br_multicast_deliver(struct net_bridge_mdb_entry *mdst,
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struct sk_buff *skb)
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{
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br_multicast_flood(mdst, skb, NULL, __br_deliver);
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}
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/* called with rcu_read_lock */
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void br_multicast_forward(struct net_bridge_mdb_entry *mdst,
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struct sk_buff *skb, struct sk_buff *skb2)
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{
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br_multicast_flood(mdst, skb, skb2, __br_forward);
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}
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#endif
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