Network Sniffer

#ifndef _IPHDR_H_
#define _IPHDR_H_

#include <pshpack1.h>
#include <ws2tcpip.h>

//
// IPv4 Header (without any IP options)
//
typedef struct ip_hdr
{
    unsigned char  ip_verlen;        // 4-bit IPv4 version
                                     // 4-bit header length (in 32-bit words)
    unsigned char  ip_tos;           // IP type of service
    unsigned short ip_totallength;   // Total length
    unsigned short ip_id;            // Unique identifier 
    unsigned short ip_offset;        // Fragment offset field
    unsigned char  ip_ttl;           // Time to live
    unsigned char  ip_protocol;      // Protocol(TCP,UDP etc)
    unsigned short ip_checksum;      // IP checksum
    unsigned int   ip_srcaddr;       // Source address
    unsigned int   ip_destaddr;      // Source address
} IPV4_HDR, *PIPV4_HDR, FAR * LPIPV4_HDR;

//
// IPv6 Header
//
typedef struct ipv6_hdr
{
    unsigned long   ipv6_vertcflow;        // 4-bit IPv6 version
                                           // 8-bit traffic class
                                           // 20-bit flow label
    unsigned short  ipv6_payloadlen;       // payload length
    unsigned char   ipv6_nexthdr;          // next header protocol value
    unsigned char   ipv6_hoplimit;         // TTL 
    struct in6_addr ipv6_srcaddr;          // Source address
    struct in6_addr ipv6_destaddr;         // Destination address
} IPV6_HDR, *PIPV6_HDR, FAR * LPIPV6_HDR;

//
// IPv6 Fragmentation Header
//
typedef struct ipv6_fragment_hdr
{
    unsigned char   ipv6_frag_nexthdr;      // Next protocol header
    unsigned char   ipv6_frag_reserved;     // Reserved: zero
    unsigned short  ipv6_frag_offset;       // Offset of fragment
    unsigned long   ipv6_frag_id;           // Unique fragment ID
} IPV6_FRAGMENT_HDR, *PIPV6_FRAGMENT_HDR, FAR * LPIPV6_FRAGMENT_HDR;

//
// Define the UDP header 
//
typedef struct udp_hdr
{
    unsigned short src_portno;       // Source port no.
    unsigned short dest_portno;      // Dest. port no.
    unsigned short udp_length;       // Udp packet length
    unsigned short udp_checksum;     // Udp checksum
} UDP_HDR, *PUDP_HDR;

//
// Define the TCP header
//
typedef struct tpc_hdr
{
    unsigned short src_portno;       // Source port no.
    unsigned short dest_portno;      // Dest. port no.
    unsigned long  seq_num;          // Sequence number
    unsigned long  ack_num;          // Acknowledgement number;
    unsigned short lenflags;         // Header length and flags
    unsigned short window_size;      // Window size
    unsigned short tcp_checksum;     // Checksum
    unsigned short tcp_urgentptr;    // Urgent data?
} TCP_HDR, *PTCP_HDR;

//
// Stucture to extract port numbers that overlays the UDP and TCP header
//
typedef struct port_hdr
{
    unsigned short src_portno;
    unsigned short dest_portno;
} PORT_HDR, *PPORT_HDR;

//
// IGMP header
//
typedef struct igmp_hdr
{
    unsigned char   version_type;
    unsigned char   max_resp_time;
    unsigned short  checksum;
    unsigned long   group_addr;
} IGMP_HDR, *PIGMP_HDR;

typedef struct igmp_hdr_query_v3
{
    unsigned char   type;
    unsigned char   max_resp_time;
    unsigned short  checksum;
    unsigned long   group_addr;
    unsigned char   resv_suppr_robust;
    unsigned char   qqi;
    unsigned short  num_sources;
    unsigned long   sources[1];
} IGMP_HDR_QUERY_V3, *PIGMP_HDR_QUERY_V3;

typedef struct igmp_group_record_v3
{
    unsigned char   type;
    unsigned char   aux_data_len;
    unsigned short  num_sources;
    unsigned long   group_addr;
    unsigned long   source_addr[1];
} IGMP_GROUP_RECORD_V3,  *PIGMP_GROUP_RECORD_V3;

typedef struct igmp_hdr_report_v3
{
    unsigned char   type;
    unsigned char   reserved1;
    unsigned short  checksum;
    unsigned short  reserved2;
    unsigned short  num_records;
} IGMP_HDR_REPORT_V3, *PIGMP_HDR_REPORT_V3;

#include <poppack.h>

#endif