![Herbert Xu](/assets/img/avatar_default.png)
This patch adds code to perform selective multicast forwarding. We forward multicast traffic to a set of ports plus all multicast router ports. In order to avoid duplications among these two sets of ports, we order all ports by the numeric value of their pointers. The two lists are then walked in lock-step to eliminate duplicates. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
256 lines
5.6 KiB
C
256 lines
5.6 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/kernel.h>
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#include <linux/netdevice.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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/* 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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p->state == BR_STATE_FORWARDING);
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}
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static inline unsigned 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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/* drop mtu oversized packets except gso */
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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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/* ip_refrag calls ip_fragment, doesn't copy the MAC header. */
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if (nf_bridge_maybe_copy_header(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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dev_queue_xmit(skb);
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}
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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(PF_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->dev = to->dev;
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NF_HOOK(PF_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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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(PF_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 (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)
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{
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if (should_deliver(to, skb)) {
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__br_forward(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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static int deliver_clone(struct net_bridge_port *prev, 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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skb = skb_clone(skb, GFP_ATOMIC);
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if (!skb) {
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struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
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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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{
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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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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)
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{
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br_flood(br, skb, NULL, __br_deliver);
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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)
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{
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br_flood(br, skb, skb2, __br_forward);
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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 *port;
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struct net_bridge_port *lport, *rport;
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struct net_bridge_port *prev;
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struct net_bridge_port_group *p;
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struct hlist_node *rp;
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prev = NULL;
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rp = br->router_list.first;
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p = mdst ? mdst->ports : NULL;
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while (p || rp) {
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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 = p->next;
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if ((unsigned long)rport >= (unsigned long)port)
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rp = rp->next;
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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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