37b090e6be
Before this patch we had two flavors of most forwarding functions - _forward and _deliver, the difference being that the latter are used when the packets are locally originated. Instead of all this function pointer passing and code duplication, we can just pass a boolean noting that the packet was locally originated and use that to perform the necessary checks in __br_forward. This gives a minor performance improvement but more importantly consolidates the forwarding paths. Also add a kernel doc comment to explain the exported br_forward()'s arguments. Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
270 lines
6.1 KiB
C
270 lines
6.1 KiB
C
/*
|
|
* Forwarding decision
|
|
* Linux ethernet bridge
|
|
*
|
|
* Authors:
|
|
* Lennert Buytenhek <buytenh@gnu.org>
|
|
*
|
|
* 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/err.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/netdevice.h>
|
|
#include <linux/netpoll.h>
|
|
#include <linux/skbuff.h>
|
|
#include <linux/if_vlan.h>
|
|
#include <linux/netfilter_bridge.h>
|
|
#include "br_private.h"
|
|
|
|
/* Don't forward packets to originating port or forwarding disabled */
|
|
static inline int should_deliver(const struct net_bridge_port *p,
|
|
const struct sk_buff *skb)
|
|
{
|
|
struct net_bridge_vlan_group *vg;
|
|
|
|
vg = nbp_vlan_group_rcu(p);
|
|
return ((p->flags & BR_HAIRPIN_MODE) || skb->dev != p->dev) &&
|
|
br_allowed_egress(vg, skb) && p->state == BR_STATE_FORWARDING;
|
|
}
|
|
|
|
int br_dev_queue_push_xmit(struct net *net, struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
if (!is_skb_forwardable(skb->dev, skb))
|
|
goto drop;
|
|
|
|
skb_push(skb, ETH_HLEN);
|
|
br_drop_fake_rtable(skb);
|
|
|
|
if (skb->ip_summed == CHECKSUM_PARTIAL &&
|
|
(skb->protocol == htons(ETH_P_8021Q) ||
|
|
skb->protocol == htons(ETH_P_8021AD))) {
|
|
int depth;
|
|
|
|
if (!__vlan_get_protocol(skb, skb->protocol, &depth))
|
|
goto drop;
|
|
|
|
skb_set_network_header(skb, depth);
|
|
}
|
|
|
|
dev_queue_xmit(skb);
|
|
|
|
return 0;
|
|
|
|
drop:
|
|
kfree_skb(skb);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(br_dev_queue_push_xmit);
|
|
|
|
int br_forward_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
return NF_HOOK(NFPROTO_BRIDGE, NF_BR_POST_ROUTING,
|
|
net, sk, skb, NULL, skb->dev,
|
|
br_dev_queue_push_xmit);
|
|
|
|
}
|
|
EXPORT_SYMBOL_GPL(br_forward_finish);
|
|
|
|
static void __br_forward(const struct net_bridge_port *to,
|
|
struct sk_buff *skb, bool local_orig)
|
|
{
|
|
struct net_bridge_vlan_group *vg;
|
|
struct net_device *indev;
|
|
struct net *net;
|
|
int br_hook;
|
|
|
|
vg = nbp_vlan_group_rcu(to);
|
|
skb = br_handle_vlan(to->br, vg, skb);
|
|
if (!skb)
|
|
return;
|
|
|
|
indev = skb->dev;
|
|
skb->dev = to->dev;
|
|
if (!local_orig) {
|
|
if (skb_warn_if_lro(skb)) {
|
|
kfree_skb(skb);
|
|
return;
|
|
}
|
|
br_hook = NF_BR_FORWARD;
|
|
skb_forward_csum(skb);
|
|
net = dev_net(indev);
|
|
} else {
|
|
if (unlikely(netpoll_tx_running(to->br->dev))) {
|
|
if (!is_skb_forwardable(skb->dev, skb)) {
|
|
kfree_skb(skb);
|
|
} else {
|
|
skb_push(skb, ETH_HLEN);
|
|
br_netpoll_send_skb(to, skb);
|
|
}
|
|
return;
|
|
}
|
|
br_hook = NF_BR_LOCAL_OUT;
|
|
net = dev_net(skb->dev);
|
|
indev = NULL;
|
|
}
|
|
|
|
NF_HOOK(NFPROTO_BRIDGE, br_hook,
|
|
net, NULL, skb, indev, skb->dev,
|
|
br_forward_finish);
|
|
}
|
|
|
|
static int deliver_clone(const struct net_bridge_port *prev,
|
|
struct sk_buff *skb, bool local_orig)
|
|
{
|
|
struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
|
|
|
|
skb = skb_clone(skb, GFP_ATOMIC);
|
|
if (!skb) {
|
|
dev->stats.tx_dropped++;
|
|
return -ENOMEM;
|
|
}
|
|
|
|
__br_forward(prev, skb, local_orig);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* br_forward - forward a packet to a specific port
|
|
* @to: destination port
|
|
* @skb: packet being forwarded
|
|
* @local_rcv: packet will be received locally after forwarding
|
|
* @local_orig: packet is locally originated
|
|
*
|
|
* Should be called with rcu_read_lock.
|
|
*/
|
|
void br_forward(const struct net_bridge_port *to,
|
|
struct sk_buff *skb, bool local_rcv, bool local_orig)
|
|
{
|
|
if (to && should_deliver(to, skb)) {
|
|
if (local_rcv)
|
|
deliver_clone(to, skb, local_orig);
|
|
else
|
|
__br_forward(to, skb, local_orig);
|
|
return;
|
|
}
|
|
|
|
if (!local_rcv)
|
|
kfree_skb(skb);
|
|
}
|
|
EXPORT_SYMBOL_GPL(br_forward);
|
|
|
|
static struct net_bridge_port *maybe_deliver(
|
|
struct net_bridge_port *prev, struct net_bridge_port *p,
|
|
struct sk_buff *skb, bool local_orig)
|
|
{
|
|
int err;
|
|
|
|
if (!should_deliver(p, skb))
|
|
return prev;
|
|
|
|
if (!prev)
|
|
goto out;
|
|
|
|
err = deliver_clone(prev, skb, local_orig);
|
|
if (err)
|
|
return ERR_PTR(err);
|
|
|
|
out:
|
|
return p;
|
|
}
|
|
|
|
/* called under rcu_read_lock */
|
|
void br_flood(struct net_bridge *br, struct sk_buff *skb,
|
|
bool unicast, bool local_rcv, bool local_orig)
|
|
{
|
|
u8 igmp_type = br_multicast_igmp_type(skb);
|
|
struct net_bridge_port *prev = NULL;
|
|
struct net_bridge_port *p;
|
|
|
|
list_for_each_entry_rcu(p, &br->port_list, list) {
|
|
/* Do not flood unicast traffic to ports that turn it off */
|
|
if (unicast && !(p->flags & BR_FLOOD))
|
|
continue;
|
|
|
|
/* Do not flood to ports that enable proxy ARP */
|
|
if (p->flags & BR_PROXYARP)
|
|
continue;
|
|
if ((p->flags & BR_PROXYARP_WIFI) &&
|
|
BR_INPUT_SKB_CB(skb)->proxyarp_replied)
|
|
continue;
|
|
|
|
prev = maybe_deliver(prev, p, skb, local_orig);
|
|
if (IS_ERR(prev))
|
|
goto out;
|
|
if (prev == p)
|
|
br_multicast_count(p->br, p, skb, igmp_type,
|
|
BR_MCAST_DIR_TX);
|
|
}
|
|
|
|
if (!prev)
|
|
goto out;
|
|
|
|
if (local_rcv)
|
|
deliver_clone(prev, skb, local_orig);
|
|
else
|
|
__br_forward(prev, skb, local_orig);
|
|
return;
|
|
|
|
out:
|
|
if (!local_rcv)
|
|
kfree_skb(skb);
|
|
}
|
|
|
|
#ifdef CONFIG_BRIDGE_IGMP_SNOOPING
|
|
/* called with rcu_read_lock */
|
|
void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
|
|
struct sk_buff *skb,
|
|
bool local_rcv, bool local_orig)
|
|
{
|
|
struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
|
|
u8 igmp_type = br_multicast_igmp_type(skb);
|
|
struct net_bridge *br = netdev_priv(dev);
|
|
struct net_bridge_port *prev = NULL;
|
|
struct net_bridge_port_group *p;
|
|
struct hlist_node *rp;
|
|
|
|
rp = rcu_dereference(hlist_first_rcu(&br->router_list));
|
|
p = mdst ? rcu_dereference(mdst->ports) : NULL;
|
|
while (p || rp) {
|
|
struct net_bridge_port *port, *lport, *rport;
|
|
|
|
lport = p ? p->port : NULL;
|
|
rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
|
|
NULL;
|
|
|
|
port = (unsigned long)lport > (unsigned long)rport ?
|
|
lport : rport;
|
|
|
|
prev = maybe_deliver(prev, port, skb, local_orig);
|
|
if (IS_ERR(prev))
|
|
goto out;
|
|
if (prev == port)
|
|
br_multicast_count(port->br, port, skb, igmp_type,
|
|
BR_MCAST_DIR_TX);
|
|
|
|
if ((unsigned long)lport >= (unsigned long)port)
|
|
p = rcu_dereference(p->next);
|
|
if ((unsigned long)rport >= (unsigned long)port)
|
|
rp = rcu_dereference(hlist_next_rcu(rp));
|
|
}
|
|
|
|
if (!prev)
|
|
goto out;
|
|
|
|
if (local_rcv)
|
|
deliver_clone(prev, skb, local_orig);
|
|
else
|
|
__br_forward(prev, skb, local_orig);
|
|
return;
|
|
|
|
out:
|
|
if (!local_rcv)
|
|
kfree_skb(skb);
|
|
}
|
|
#endif
|