以太网帧结构

struct ethhdr { 

unsigned char 
  h_dest[ETH_ALEN]; 
 /* destination eth addr 
 */ 

unsigned char 
  h_source[ETH_ALEN]; 
 /* source ether addr 
 */ 

__be16 
  h_proto; 
 /* packet type ID field 
 */ 

 } __attribute__((packed)); 

/* 协议ID，即h_proto可使用的值
  * These are the defined Ethernet Protocol ID's.
  */


 #define ETH_P_LOOP 0x0060 /* Ethernet Loopback packet */
 #define ETH_P_PUP 0x0200 /* Xerox PUP packet */
 #define ETH_P_PUPAT 0x0201 /* Xerox PUP Addr Trans packet */
 #define ETH_P_TSN 0x22F0 /* TSN (IEEE 1722) packet */
 #define ETH_P_IP 0x0800 /* Internet Protocol packet */
 #define ETH_P_X25 0x0805 /* CCITT X.25 */
 #define ETH_P_ARP 0x0806 /* Address Resolution packet */
 #define ETH_P_BPQ 0x08FF /* G8BPQ AX.25 Ethernet Packet [ NOT AN OFFICIALLY REGISTERED ID ] */
 #define ETH_P_IEEEPUP 0x0a00 /* Xerox IEEE802.3 PUP packet */
 #define ETH_P_IEEEPUPAT 0x0a01 /* Xerox IEEE802.3 PUP Addr Trans packet */
 #define ETH_P_BATMAN 0x4305 /* B.A.T.M.A.N.-Advanced packet [ NOT AN OFFICIALLY REGISTERED ID ] */
 #define ETH_P_DEC       0x6000          /* DEC Assigned proto           */
 #define ETH_P_DNA_DL    0x6001          /* DEC DNA Dump/Load            */
 #define ETH_P_DNA_RC    0x6002          /* DEC DNA Remote Console       */
 #define ETH_P_DNA_RT    0x6003          /* DEC DNA Routing              */
 #define ETH_P_LAT       0x6004          /* DEC LAT                      */
 #define ETH_P_DIAG      0x6005          /* DEC Diagnostics              */
 #define ETH_P_CUST      0x6006          /* DEC Customer use             */
 #define ETH_P_SCA       0x6007          /* DEC Systems Comms Arch       */
 #define ETH_P_TEB 0x6558 /* Trans Ether Bridging */
 #define ETH_P_RARP      0x8035 /* Reverse Addr Res packet */
 #define ETH_P_ATALK 0x809B /* Appletalk DDP */
 #define ETH_P_AARP 0x80F3 /* Appletalk AARP */
 #define ETH_P_8021Q 0x8100          /* 802.1Q VLAN Extended Header  */
 #define ETH_P_IPX 0x8137 /* IPX over DIX */
 #define ETH_P_IPV6 0x86DD /* IPv6 over bluebook */
 #define ETH_P_PAUSE 0x8808 /* IEEE Pause frames. See 802.3 31B */
 #define ETH_P_SLOW 0x8809 /* Slow Protocol. See 802.3ad 43B */
 #define ETH_P_WCCP 0x883E /* Web-cache coordination protocol
* defined in draft-wilson-wrec-wccp-v2-00.txt */
 #define ETH_P_MPLS_UC 0x8847 /* MPLS Unicast traffic */
 #define ETH_P_MPLS_MC 0x8848 /* MPLS Multicast traffic */
 #define ETH_P_ATMMPOA 0x884c /* MultiProtocol Over ATM */
 #define ETH_P_PPP_DISC 0x8863 /* PPPoE discovery messages     */
 #define ETH_P_PPP_SES 0x8864 /* PPPoE session messages */
 #define ETH_P_LINK_CTL 0x886c /* HPNA, wlan link local tunnel */
 #define ETH_P_ATMFATE 0x8884 /* Frame-based ATM Transport
* over Ethernet
*/
 #define ETH_P_PAE 0x888E /* Port Access Entity (IEEE 802.1X) */
 #define ETH_P_AOE 0x88A2 /* ATA over Ethernet */
 #define ETH_P_8021AD 0x88A8          /* 802.1ad Service VLAN */
 #define ETH_P_802_EX1 0x88B5 /* 802.1 Local Experimental 1.  */
 #define ETH_P_TIPC 0x88CA /* TIPC */
 #define ETH_P_MACSEC 0x88E5 /* 802.1ae MACsec */
 #define ETH_P_8021AH 0x88E7          /* 802.1ah Backbone Service Tag */
 #define ETH_P_MVRP 0x88F5          /* 802.1Q MVRP                  */
 #define ETH_P_1588 0x88F7 /* IEEE 1588 Timesync */
 #define ETH_P_PRP 0x88FB /* IEC 62439-3 PRP/HSRv0 */
 #define ETH_P_FCOE 0x8906 /* Fibre Channel over Ethernet  */
 #define ETH_P_TDLS 0x890D          /* TDLS */
 #define ETH_P_FIP 0x8914 /* FCoE Initialization Protocol */
 #define ETH_P_80221 0x8917 /* IEEE 802.21 Media Independent Handover Protocol */
 #define ETH_P_HSR 0x892F /* IEC 62439-3 HSRv1 */
 #define ETH_P_LOOPBACK 0x9000 /* Ethernet loopback packet, per IEEE 802.3 */
 #define ETH_P_QINQ1 0x9100 /* deprecated QinQ VLAN [ NOT AN OFFICIALLY REGISTERED ID ] */
 #define ETH_P_QINQ2 0x9200 /* deprecated QinQ VLAN [ NOT AN OFFICIALLY REGISTERED ID ] */
 #define ETH_P_QINQ3 0x9300 /* deprecated QinQ VLAN [ NOT AN OFFICIALLY REGISTERED ID ] */
 #define ETH_P_EDSA 0xDADA /* Ethertype DSA [ NOT AN OFFICIALLY REGISTERED ID ] */
 #define ETH_P_AF_IUCV   0xFBFB /* IBM af_iucv [ NOT AN OFFICIALLY REGISTERED ID ] */


 #define ETH_P_802_3_MIN 0x0600 /* If the value in the ethernet type is less than this value
* then the frame is Ethernet II. Else it is 802.3 */


 /*
  * Non DIX types. Won't clash for 1500 types.
  */


 #define ETH_P_802_3 0x0001 /* Dummy type for 802.3 frames  */
 #define ETH_P_AX25 0x0002 /* Dummy protocol id for AX.25  */
 #define ETH_P_ALL 0x0003 /* Every packet (be careful!!!) */
 #define ETH_P_802_2 0x0004 /* 802.2 frames */
 #define ETH_P_SNAP 0x0005 /* Internal only */
 #define ETH_P_DDCMP     0x0006          /* DEC DDCMP: Internal only     */
 #define ETH_P_WAN_PPP   0x0007          /* Dummy type for WAN PPP frames*/
 #define ETH_P_PPP_MP    0x0008          /* Dummy type for PPP MP frames */
 #define ETH_P_LOCALTALK 0x0009 /* Localtalk pseudo type */
 #define ETH_P_CAN 0x000C /* CAN: Controller Area Network */
 #define ETH_P_CANFD 0x000D /* CANFD: CAN flexible data rate*/
 #define ETH_P_PPPTALK 0x0010 /* Dummy type for Atalk over PPP*/
 #define ETH_P_TR_802_2 0x0011 /* 802.2 frames */
 #define ETH_P_MOBITEX 0x0015 /* Mobitex ([email protected]) */
 #define ETH_P_CONTROL 0x0016 /* Card specific control frames */
 #define ETH_P_IRDA 0x0017 /* Linux-IrDA */
 #define ETH_P_ECONET 0x0018 /* Acorn Econet */
 #define ETH_P_HDLC 0x0019 /* HDLC frames */
 #define ETH_P_ARCNET 0x001A /* 1A for ArcNet :-)            */
 #define ETH_P_DSA 0x001B /* Distributed Switch Arch. */
 #define ETH_P_TRAILER 0x001C /* Trailer switch tagging */
 #define ETH_P_PHONET 0x00F5 /* Nokia Phonet frames          */
 #define ETH_P_IEEE802154 0x00F6 /* IEEE802.15.4 frame */
 #define ETH_P_CAIF 0x00F7 /* ST-Ericsson CAIF protocol */
 #define ETH_P_XDSA 0x00F8 /* Multiplexed DSA protocol */