neti.h

/*
 * name: neti.h
 * author: Jean Philippe GUILLEMIN <jpgu@users.sourceforge.net>
 * Copyright (C) 2002 by Jean Philippe GUILLEMIN <jp.guillemin@free.fr>
 * license: This software is under GPL version 2 of license
 * date: 04 17 2003
 * rev: 0.8
*/

#define __BYTE_ORDER __LITTLE_ENDIAN

#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <netinet/ip_icmp.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <sysexits.h>
#include <stdlib.h>
#include <getopt.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/time.h>
#include <time.h>


struct pseudohdr		/* this struct is used to calculate the TCP & UDP checsum */
{
	u_int32_t saddr;
	u_int32_t daddr;
	unsigned char zero;
	unsigned char protocol;
	u_int16_t lenght;
};
/*
	0      7 8     15 16    23 24    31

	+--------+--------+--------+--------+
    |          source address           |
	+--------+--------+--------+--------+
	|        destination address        |
	+--------+--------+--------+--------+
	|  zero  |protocol|  UDP/TCP length |
	+--------+--------+--------+--------+
*/



struct optionhdr
{
	u_int32_t data_size;
	u_int32_t inet_src_ip;
	u_int32_t inet_dst_ip;
	char src_ip[32];
	char dst_ip[32];
	u_int16_t proto;
	u_int16_t lenght;
	u_int32_t inet_dst_port;
	u_int32_t inet_src_port;
	u_int32_t src_port;
	u_int32_t dst_port;
	u_int32_t syn;
	u_int32_t ack;
	u_int32_t psh;
	u_int32_t rst;
	u_int32_t fin;
	u_int32_t urg;
	u_int16_t ttl;
	u_int32_t window;
	u_int16_t offset;
	u_int16_t icmp_type;
	u_int16_t icmp_code;
	u_int32_t icmp_echo_id;
	u_int32_t icmp_echo_sequence;
	unsigned char iptos;
	char icmp_redirect_gateway[32];
	char interface[32];
	int tcp_opt_size;
};

struct filter {
	u_int16_t filter_on_icmp;
	u_int16_t filter_on_udp;
	u_int16_t filter_on_tcp;
	u_int16_t filter_on_target_addr;
};


struct icmp_timestamp {
	unsigned long originate;
	unsigned long receive;
	unsigned long transmit;
};


#define DOUBLE 32
#define TCPHDR_SIZE sizeof (struct tcphdr)
#define UDPHDR_SIZE sizeof (struct udphdr)
#define PSEUDOHDR_SIZE sizeof (struct pseudohdr)
#define IPHDR_SIZE sizeof (struct ip)
#define ICMPHDR_SIZE sizeof (struct icmphdr)
#define IFREQ_SIZE sizeof(struct ifreq)
#define HOSTENT_SIZE sizeof(struct hostent)
#define ICMP_TIMESTAMP_SIZE sizeof(struct icmp_timestamp);
#define MF   0x2000  /* More IP fragment flag */



/**********************/
/*      GLOBALS       */
/**********************/


char *payload, *data;
char last_address[32];
char last_name[1024];
struct optionhdr *myhdr;
struct filter *waitfor;
int so_udp, so_tcp, so_icmp, *so_send, so_raw; /* sockets identifiers */
u_int16_t be_promiscuous, flood, keep_sniffing, no_lookup, use_this_if, use_this_address, be_blind, do_reverse_lookup;
u_int32_t time_to_wait_for_packet;


/**********************/
/*      PROTOTYPES    */
/**********************/

/* main program */
int main(int argc, char *argv[]);

/* print() prototype
param1 : rlookup = [0,1] tell print() to perform a reverse lookup (1) or no (0)
*/
void print(u_int16_t rlookup);

/*	to quit clean  	 */
void close_sockets(void);

/* function that create the UDP header and data field 
the result is a pointer (*udp_packet) to the begining of UDP header
*/
int write_udp(char *udp_packet, int size, u_int32_t ip_saddr, u_int32_t ip_daddr);

/* function that create the TCP header and data field 
the result is a pointer (*tcp_packet) to the begining of TCP header
*/
int write_tcp(char *tcp_packet, int size, u_int32_t ip_saddr, u_int32_t ip_daddr);

/* function that create the ICMP header and data field 
the result is a pointer (*icmp_packet) to the begining of ICMP header
*/
int write_icmp(char *icmp_packet, int size);

/* calculate all checksums */
u_int16_t sum(u_int16_t *buf, int nbytes);

/* get the IP address of a given interface */
int getif_ip_by_name(char *ip, u_int32_t *inet_ip, char *ifname);

/* Get IP address of the output interface from the routing table 
(Derived from R.Stevens) */
int getout_ip(struct sockaddr_in *if_addr, struct sockaddr_in *dest);
	
/* Gets the name of output interface from a given address */
int getif_name_by_ip(char *ifname, u_int32_t *inet_ip);

/* sniff incoming packets */
int sniff(int udp_sniff_sock, int tcp_sniff_sock, int icmp_sniff_sock, int keep, 
u_int32_t timeout, u_int16_t rlookup);

/* resolve given hostname into IP address and reverse :) */
int lookup(u_int32_t *inet_ip, char *ip, char *name);
int reverse_lookup(char *name, char *ip);

/* sets and unsets listening interface in promiscuous mode */
int set_promisc(int sock);
int unset_promisc(int sock);

/*  find the max socket id for select()  */
int max(int a, int b, int c);

/* try to find parameters in given config file using the func parse_from_config()	*/
int take_args_from_file(char *cfile);

/* scan the config file to find given parameter and return the associated value in uint & char	*/
int parse_from_config(u_int32_t *uint_value, char *char_value, char *filename, 
char *param );

/*  multi use debug function  */
int debug();

/* catch_sig() prototype */
void catch_sig(int);