netif_receive_skb()

process_backlog() -->
netif_receive_skb()

/usr/src/linux-2.6.19/net/core/dev.c

int netif_receive_skb(struct sk_buff *skb)
{
    struct packet_type *ptype,
*pt_prev;
    struct net_device *orig_dev;
    int ret = NET_RX_DROP;
    unsigned short type;

    if (skb->dev->poll && netpoll_rx(skb))
        return NET_RX_DROP;
    if (!skb->tstamp.off_sec)
        net_timestamp(skb);
    if (!skb->input_dev)
        skb->input_dev = skb->dev;

    orig_dev = skb_bond(skb);
    if (!orig_dev)
        return NET_RX_DROP;

    __get_cpu_var(netdev_rx_stat).total++;
    skb->h.raw = skb->nh.raw = skb->data;
    skb->mac_len = skb->nh.raw - skb->mac.raw;
    pt_prev = NULL;
    rcu_read_lock();

#ifdef CONFIG_NET_CLS_ACT
    if (skb->tc_verd & TC_NCLS) {
        skb->tc_verd = CLR_TC_NCLS(skb->tc_verd);
        goto ncls;
    }
#endif

    list_for_each_entry_rcu(ptype, &ptype_all, list) {
        if (!ptype->dev || ptype->dev == skb->dev) {
            if (pt_prev)
                ret = deliver_skb(skb, pt_prev, orig_dev);
            pt_prev = ptype;
        }
    }

#ifdef CONFIG_NET_CLS_ACT
    if (pt_prev) {
        ret = deliver_skb(skb, pt_prev, orig_dev);
        pt_prev = NULL; 
    } else {
        skb->tc_verd = SET_TC_OK2MUNGE(skb->tc_verd);
    }
    ret = ing_filter(skb);    
    if (ret == TC_ACT_SHOT || (ret == TC_ACT_STOLEN)) {
        kfree_skb(skb);
        goto out;
    }
    skb->tc_verd = 0;
ncls:
#endif

    handle_diverter(skb);
    if (handle_bridge(&skb, &pt_prev, &ret, orig_dev))
        goto out;
    type = skb->protocol;

    list_for_each_entry_rcu(ptype, &ptype_base[ntohs(type)&15], list) {
        if (ptype->type == type &&
            (!ptype->dev || ptype->dev == skb->dev)) {
            if (pt_prev)
                ret = deliver_skb(skb, pt_prev, orig_dev);
            pt_prev = ptype;
        }
    }

    if (pt_prev) {
        ret = pt_prev->func(skb,
skb->dev, pt_prev, orig_dev);
    } else {
        kfree_skb(skb);
        ret = NET_RX_DROP;
    }

out:
    rcu_read_unlock();
    return ret;
}