- 论坛徽章:
- 16
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static int ip_rcv_finish(struct sk_buff *skb)
{
const struct iphdr *iph = ip_hdr(skb);
struct rtable *rt;
/*
* Initialise the virtual path cache for the packet. It describes
* how the packet travels inside Linux networking.
*/
if (skb->dst == NULL) {
int err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
skb->dev);
if (unlikely(err)) {
if (err == -EHOSTUNREACH)
IP_INC_STATS_BH(dev_net(skb->dev),
IPSTATS_MIB_INADDRERRORS);
else if (err == -ENETUNREACH)
IP_INC_STATS_BH(dev_net(skb->dev),
IPSTATS_MIB_INNOROUTES);
goto drop;
}
}
#ifdef CONFIG_NET_CLS_ROUTE
if (unlikely(skb->dst->tclassid)) {
struct ip_rt_acct *st = per_cpu_ptr(ip_rt_acct, smp_processor_id());
u32 idx = skb->dst->tclassid;
st[idx&0xFF].o_packets++;
st[idx&0xFF].o_bytes+=skb->len;
st[(idx>>16)&0xFF].i_packets++;
st[(idx>>16)&0xFF].i_bytes+=skb->len;
}
#endif
if (iph->ihl > 5 && ip_rcv_options(skb))
goto drop;
rt = skb->rtable;
if (rt->rt_type == RTN_MULTICAST)
IP_INC_STATS_BH(dev_net(rt->u.dst.dev), IPSTATS_MIB_INMCASTPKTS);
else if (rt->rt_type == RTN_BROADCAST)
IP_INC_STATS_BH(dev_net(rt->u.dst.dev), IPSTATS_MIB_INBCASTPKTS);
return dst_input(skb);
drop:
kfree_skb(skb);
return NET_RX_DROP;
}
红色的标志:其中,skb->dst为NULL时候,ip_route_input主要查找路由表来决定转发的路径嘛?
如果skb->dst不为NULL,是在哪里进行赋值的呢?好像驱动调用netif_rx之前没有进行此操作,netif_rx也没有进行此操作,net_rx_action,netif_rx_buff以及ip_rcv都没有进行此操作。
望在学习linux网络协议栈的来讨论哈撒 望高手指导 |
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