/*
* Return NULL if skb is handled
* note: already called with rcu_read_lock
*/
struct sk_buff *br_handle_frame(struct sk_buff *skb)
{
struct net_bridge_port *p;
const unsigned char *dest = eth_hdr(skb)->h_dest;
int (*rhook)(struct sk_buff *skb);
if (skb->pkt_type == PACKET_LOOPBACK)
return skb;
if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
goto drop;
skb = skb_share_check(skb, GFP_ATOMIC);
if (!skb)
return NULL;
p = br_port_get_rcu(skb->dev);
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;
/* If STP is turned off, then forward */
if (p->br->stp_enabled == BR_NO_STP && dest[5] == 0)
goto forward;
if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
NULL, br_handle_local_finish))
return NULL; /* frame consumed by filter */
else
return skb; /* continue processing */
}
forward:
switch (p->state) {
case BR_STATE_FORWARDING:
rhook = rcu_dereference(br_should_route_hook);
if (rhook != NULL) {
if (rhook(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(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
br_handle_frame_finish);
break;
default:
drop:
kfree_skb(skb);
}
return NULL;
}
/*
* 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;
int (*rhook)(struct sk_buff *skb);
//源MAC地址为非法，返回错误，丢弃数据包
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:
rhook = rcu_dereference(br_should_route_hook);
if (rhook != NULL)
{
if (rhook(skb))
return skb;
dest = eth_hdr(skb)->h_dest;
}
/* fall through */
case BR_STATE_LEARNING: //如果网桥状态处于学习状态，则更新数据库
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;
}
struct sk_buff *br_handle_frame(struct net_bridge_port *p, struct sk_buff *skb)
{
const unsigned char *dest = eth_hdr(skb)->h_dest;
int (*rhook)(struct sk_buff *skb);
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))) {
if (skb->protocol == htons(ETH_P_PAUSE))
goto drop;
if (p->br->stp_enabled == BR_NO_STP && dest[5] == 0)
goto forward;
if (NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
NULL, br_handle_local_finish))
return NULL;
else
return skb;
}
forward:
switch (p->state) {
case BR_STATE_FORWARDING:
rhook = rcu_dereference(br_should_route_hook);
if (rhook != NULL) {
if (rhook(skb))
return skb;
dest = eth_hdr(skb)->h_dest;
}
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;
}
