/* Ensure network structures aren't padded (DJGPP and VC) */
#define MAXDATA 1500 /* Maximum Ethernet data size */
#define MAXPACK (MAXDATA+14) /* Maximum packet size (incl. datalink hdr) */
#define MAXSEG (MAXDATA-40) /* Maximum TCP data ('segment') size */
#define BCASTIP 0xffffffffL /* Broadcast IP address */
#define PCOL_ARP 0x0806 /* Protocol type: ARP */
#define PCOL_IP 0x0800 /* IP */
/* Structure for one node */
typedef struct
{
BYTE mac[6]; /* MAC (Ethernet) addr */
LWORD ip; /* IP addr */
LWORD mask; /* Subnet mask */
LWORD gate; /* Gateway addr */
WORD port; /* TCP or UDP port number */
} NODE;
/* ***** ARP (Address Resolution Protocol) packet ***** */
typedef struct
{
WORD hrd, /* Hardware type */
pro; /* Protocol type */
BYTE hln, /* Len of h/ware addr (6) */
pln; /* Len of IP addr (4) */
WORD op; /* ARP opcode */
BYTE smac[MACLEN]; /* Source MAC (Ethernet) addr */
LWORD sip; /* Source IP addr */
BYTE dmac[MACLEN]; /* Destination Enet addr */
LWORD dip; /* Destination IP addr */
} ARPKT;
#define HTYPE 0x0001 /* Hardware type: ethernet */
#define ARPPRO 0x0800 /* Protocol type: IP */
#define ARPXXX 0x0000 /* ARP opcodes: unknown opcode */
#define ARPREQ 0x0001 /* ARP request */
#define ARPRESP 0x0002 /* ARP response */
#define RARPREQ 0x0003 /* RARP request */
#define RARPRESP 0x0004 /* RARP response */
/* ***** IP (Internet Protocol) header ***** */
typedef struct
{
BYTE vhl, /* Version and header len */
service; /* Quality of IP service */
WORD len, /* Total len of IP datagram */
ident, /* Identification value */
frags; /* Flags & fragment offset */
BYTE ttl, /* Time to live */
pcol; /* Protocol used in data area */
WORD check; /* Header checksum */
LWORD 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 (MAXFRAME-sizeof(IPHDR))
typedef struct
{
IPHDR i; /* IP header */
BYTE ipdata[MAXIP]; /* Data area */
} IPKT;
/* ***** ICMP (Internet Control Message Protocol) header ***** */
typedef struct
{
BYTE type, /* Message type */
codetype; /* Message code */
WORD 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 */
BYTE icmpdata[MAXICMP]; /* Data area */
} ICMPKT;
/* ***** UDP (User Datagram Protocol) header ***** */
typedef struct udph
{
WORD 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 */
BYTE 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... */
{
LWORD srce, /* Source IP address */
dest; /* Destination IP address */
BYTE z, /* Zero */
pcol; /* Protocol byte */
WORD len; /* UDP length field */
} PHDR;
/* ***** TCP (Transmission Control Protocol) header ***** */
typedef struct tcph
{
WORD sport, /* Source port */
dport; /* Destination port */
LWORD seq, /* Sequence number */
ack; /* Ack number */
BYTE hlen, /* TCP header len (num of bytes << 2) */
flags; /* Option flags */
WORD 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 */
BYTE tcpdata[MAXTCP]; /* Data area (oversized) */
} TCPKT;
/* Prototypes */
int is_arp(ETHERFRAME *efp, int len);
int make_arp(ETHERFRAME *efp, NODE *srcep, NODE *destp, WORD codetype);
int is_ip(ETHERFRAME *efp, int len);
int make_ip(ETHERFRAME *efp, NODE *srcep, NODE *destp, BYTE pcol, WORD dlen);
void getip_srce(ETHERFRAME *efp, NODE *np);
int getip_locdest(ETHERFRAME *efp,NODE *np);
LWORD gate_ip(NODE *remp, NODE *locp);
int on_subnet(LWORD remip, NODE *locp);
int is_icmp(IPKT *ip, int len);
int make_icmp(ETHERFRAME *efp, NODE *srcep, NODE *destp, BYTE type, BYTE codetype,WORD dlen);
//int icmp_unreach(ETHERFRAME *efp, NODE *srcep, NODE *destp, BYTE codetype);
/* EOF */
