Linux常见协议类型结构体定义

以太头：

#include <linux/if_inet.h>

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));

IP头：

#include <linux/ip.h>

struct iphdr {
#if defined(__LITTLE_ENDIAN_BITFIELD)
	__u8	ihl:4,
		version:4;
#elif defined (__BIG_ENDIAN_BITFIELD)
	__u8	version:4,
  		ihl:4;
#else
#error	"Please fix <asm/byteorder.h>"
#endif
	__u8	tos;
	__be16	tot_len;
	__be16	id;
	__be16	frag_off;
	__u8	ttl;
	__u8	protocol;
	__sum16	check;
	__be32	saddr;
	__be32	daddr;
	/*The options start here. */
};

ICMP头：

#include <linux/icmp.h>

struct icmphdr {
  __u8		type;
  __u8		code;
  __sum16	checksum;
  union {
	struct {
		__be16	id;
		__be16	sequence;
	} echo;
	__be32	gateway;
	struct {
		__be16	__unused;
		__be16	mtu;
	} frag;
  } un;
};

TCP头：

#include <linux/tcp.h>

struct tcphdr {
	__be16	source;
	__be16	dest;
	__be32	seq;
	__be32	ack_seq;
#if defined(__LITTLE_ENDIAN_BITFIELD)
	__u16	res1:4,
		doff:4,
		fin:1,
		syn:1,
		rst:1,
		psh:1,
		ack:1,
		urg:1,
		ece:1,
		cwr:1;
#elif defined(__BIG_ENDIAN_BITFIELD)
	__u16	doff:4,
		res1:4,
		cwr:1,
		ece:1,
		urg:1,
		ack:1,
		psh:1,
		rst:1,
		syn:1,
		fin:1;
#else
#error	"Adjust your <asm/byteorder.h> defines"
#endif	
	__be16	window;
	__sum16	check;
	__be16	urg_ptr;
};

UDP头：

#include <linux/udp.h>

struct udphdr {
	__be16	source;
	__be16	dest;
	__be16	len;
	__sum16	check;
};