gprs_ip.h

gprs协议实现

/* Ensure network structures aren't padded (DJGPP and VC) */

#define MAXDATA 1500            /* Maximum Ethernet data size */
#define MAXPACK (MAXDATA-8)    /* Maximum packet size (incl. datalink hdr) */
#define MAXSEG (MAXDATA-40)     /* Maximum TCP data ('segment') size */

/* Structure for one node */
typedef struct
{
    unsigned long  	ip;                   /* IP addr */
    unsigned short   	port;                 /* TCP or UDP port number */
} NODE;

/* ***** IP (Internet Protocol) header ***** */
typedef struct
{
    unsigned char  	vhl,              /* Version and header len */
          	   	service;          /* Quality of IP service */
    unsigned short 	len,              /* Total len of IP datagram */
          		ident,            /* Identification value */
          		frags;            /* Flags & fragment offset */
    unsigned char	ttl,              /* Time to live */
          		pcol;             /* Protocol used in data area */
    unsigned short	check;            /* Header checksum */
    unsigned long	sip,              /* IP source addr */
          		dip;              /* IP dest addr */
} IPHDR;

#define PICMP   1           /* Protocol type: ICMP */
#define PTCP    6           /*                TCP */
#define PUDP   17           /*                UDP */

/* ***** IP packet ('datagram') ***** */
#define MAXIP (MAXPACK-sizeof(IPHDR))
typedef struct
{
    IPHDR  i;               /* IP header */
    unsigned char   ipdata[MAXIP];     /* Data area */
} IPKT;

/* ***** ICMP (Internet Control Message Protocol) header ***** */
typedef struct
{
    unsigned char  	type,             /* Message type */
          		codetype;         /* Message code */
    unsigned short  	check,            /* Checksum */
          		ident,            /* Identifier (possibly unused) */
          		seq;              /* Sequence number (possibly unused) */
} ICMPHDR;

#define ICREQ           8   /* Message type: echo request */
#define ICREP           0   /*               echo reply */
#define ICUNREACH       3   /*               destination unreachable */
#define ICQUENCH        4   /*               source quench */
#define UNREACH_NET     0   /* Destination Unreachable codes: network */
#define UNREACH_HOST    1   /*                                host */
#define UNREACH_PORT    3   /*                                port */
#define UNREACH_FRAG    4   /*     fragmentation needed, but disable flag set */

/* ***** ICMP packet ('datagram') ***** */
#define MAXICMP (MAXIP-sizeof(ICMPHDR))
typedef struct icmp
{
    IPHDR    i;             /* IP header */
    ICMPHDR  c;             /* ICMP header */
    unsigned char     icmpdata[MAXICMP]; /* Data area */
} ICMPKT;

/* ***** UDP (User Datagram Protocol) header ***** */
typedef struct udph
{
    unsigned short  	sport,            /* Source port */
          		dport,            /* Destination port */
          		len,              /* Length of datagram + this header */
          		check;            /* Checksum of data, header + pseudoheader */
} UDPHDR;

#define MAXUDP (MAXIP-sizeof(UDPHDR))
/* ***** UDP packet ('datagram') ***** */
typedef struct udp
{
    IPHDR   			i;			/* IP header */
    UDPHDR  			u;    			/* UDP header */
    unsigned char	    udpdata[MAXUDP];  		/* Data area */
} UDPKT;

/* ***** Pseudo-header for UDP or TCP checksum calculation ***** */
/* The integers must be in hi-lo byte order for checksum */

typedef struct              /* Pseudo-header... */
{
    unsigned long 	srce,             /* Source IP address */
          		dest;             /* Destination IP address */
    unsigned char	z,                /* Zero */
          		pcol;             /* Protocol byte */
    unsigned short	len;              /* UDP length field */
} PHDR;

/* ***** TCP (Transmission Control Protocol) header ***** */
typedef struct tcph
{
    unsigned short  	sport,            /* Source port */
          		dport;            /* Destination port */
    unsigned long 	seq,              /* Sequence number */
          		ack;              /* Ack number */
    unsigned char  	hlen,             /* TCP header len (num of bytes << 2) */
          		flags;            /* Option flags */
    unsigned short  	window,           /* Flow control credit (num of bytes) */
          		check,            /* Checksum */
          		urgent;           /* Urgent data pointer */
} TCPHDR;

#define MAXTCP (MAXIP-sizeof(TCPHDR))
#define TFIN        0x01    /* Option flags: no more data */
#define TSYN        0x02    /*           sync sequence nums */
#define TRST        0x04    /*           reset connection */
#define TPUSH       0x08    /*           push buffered data */
#define TACK        0x10    /*           acknowledgement */
#define TURGE       0x20    /*           urgent */

/* ***** TCP packet ('segment') ***** */
typedef struct tcp
{
    IPHDR   		i;                /* IP header */
    TCPHDR  		t;                /* TCP header */
    unsigned char    	tcpdata[MAXTCP];  /* Data area (oversized) */
} TCPKT;



extern IPKT * ip_in;		// 接收的IP 数据包
extern IPKT * ip_out;		// 要发送的IP 数据包
extern NODE  locnode;		//本机的节点信息结构(ip,port)

/* Prototypes */
short is_ip(short len);
void make_ip(NODE *srcep, NODE *destp, unsigned char pcol, unsigned short dlen);
void swap_ip(IPKT * ip);
void getip_srce(NODE *np);
unsigned short getip_locdest(NODE *np);
short is_icmp(short len);
void make_icmp(NODE *srcep, NODE *destp, unsigned char type, unsigned char codetype,unsigned char *dat,unsigned short dlen);
//short icmp_unreach(NODE *srcep, NODE *destp, BYTE codetype);

/* EOF */