协议处理函数

1: struct packet_type {

2: __be16 type; /* This is really htons(ether_type). */

3: struct net_device *dev; /* NULL is wildcarded here */为NULL时指代所有的设备

4: int (*func) (struct sk_buff *,

5: struct net_device *,

6: struct packet_type *,

7: struct net_device *);

8: struct sk_buff *(*gso_segment)(struct sk_buff *skb,

9: netdev_features_t features);

10: int (*gso_send_check)(struct sk_buff *skb);

11: struct sk_buff **(*gro_receive)(struct sk_buff **head,

12: struct sk_buff *skb);

13: int (*gro_complete)(struct sk_buff *skb);

14: void *af_packet_priv;由PF_PACKET套接字使用&＃xff0c;指向于packet_type结构建立相关联的sock数据结构。

15: struct list_head list;冲突消除链表

16: };

1: void dev_add_pack(struct packet_type *pt)

2: {

3: struct list_head *head &＃61; ptype_head(pt);

4:  

5: spin_lock(&ptype_lock);

6: list_add_rcu(&pt->list, head);

7: spin_unlock(&ptype_lock);

8: }

9: EXPORT_SYMBOL(dev_add_pack);

1: void __dev_remove_pack(struct packet_type *pt)

2: {

3: struct list_head *head &＃61; ptype_head(pt);

4: struct packet_type *pt1;

5:  

6: spin_lock(&ptype_lock);

7:  

8: list_for_each_entry(pt1, head, list) {

9: if (pt &＃61;&＃61; pt1) {

10: list_del_rcu(&pt->list);

11: goto out;

12: }

13: }

14:  

15: printk(KERN_WARNING "dev_remove_pack: %p not found.\n", pt);

16: out:

17: spin_unlock(&ptype_lock);

18: }

19: EXPORT_SYMBOL(__dev_remove_pack);

1: /**

2: * eth_type_trans - determine the packet&＃39;s protocol ID.

3: * &＃64;skb: received socket data

4: * &＃64;dev: receiving network device

5: *

6: * The rule here is that we

7: * assume 802.3 if the type field is short enough to be a length.

8: * This is normal practice and works for any &＃39;now in use&＃39; protocol.

9: */

10: __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev)

11: {

12: struct ethhdr *eth;

13:  

14: skb->dev &＃61; dev;

15: skb_reset_mac_header(skb);

16: skb_pull_inline(skb, ETH_HLEN);

17: eth &＃61; eth_hdr(skb);

18:  

19: if (unlikely(is_multicast_ether_addr(eth->h_dest))) {

20: if (!compare_ether_addr_64bits(eth->h_dest, dev->broadcast))

21: skb->pkt_type &＃61; PACKET_BROADCAST;

22: else

23: skb->pkt_type &＃61; PACKET_MULTICAST;

24: }

25:  

26: /*

27: * This ALLMULTI check should be redundant by 1.4

28: * so don&＃39;t forget to remove it.

29: *

30: * Seems, you forgot to remove it. All silly devices

31: * seems to set IFF_PROMISC.

32: */

33:  

34: else if (1 /*dev->flags&IFF_PROMISC */ ) {

35: if (unlikely(compare_ether_addr_64bits(eth->h_dest, dev->dev_addr)))

36: &＃61; PACKET_OTHERHOST;

37: }

38:  

39: /*

40: * Some variants of DSA tagging don&＃39;t have an ethertype field

41: * at all, so we check here whether one of those tagging

42: * variants has been configured on the receiving interface,

43: * and if so, set skb->protocol without looking at the packet.

44: */

45: if (netdev_uses_dsa_tags(dev))

46: return htons(ETH_P_DSA);

47: if (netdev_uses_trailer_tags(dev))

48: return htons(ETH_P_TRAILER);

49:  

50:

52:  

53: /*

54: * This is a magic hack to spot IPX packets. Older Novell breaks

55: * the protocol design and runs IPX over 802.3 without an 802.2 LLC

56: * layer. We look for FFFF which isn&＃39;t a used 802.2 SSAP/DSAP. This

57: * won&＃39;t work for fault tolerant netware but does for the rest.

58: */

59: if (skb->len >&＃61; 2 && *(unsigned short *)(skb->data) &＃61;&＃61; 0xFFFF)

60: return htons(ETH_P_802_3);

61:  

62: /*

63: * Real 802.2 LLC

64: */

65: return htons(ETH_P_802_2);

66: }

67: EXPORT_SYMBOL(eth_type_trans);