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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <arpa/inet.h>
#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
#include <libnetfilter_conntrack/libnetfilter_conntrack_tcp.h>
/*
* This example shows how to setup a user-space expectation. This requires
* a Linux kernel >= 2.6.37.
*/
int main(void)
{
int ret;
struct nfct_handle *h;
struct nf_conntrack *master, *expected, *mask;
struct nf_expect *exp;
/*
* Step 1: Setup master conntrack
*/
master = nfct_new();
if (!master) {
perror("nfct_new");
exit(EXIT_FAILURE);
}
nfct_set_attr_u8(master, ATTR_L3PROTO, AF_INET);
nfct_set_attr_u32(master, ATTR_IPV4_SRC, inet_addr("1.1.1.1"));
nfct_set_attr_u32(master, ATTR_IPV4_DST, inet_addr("2.2.2.2"));
nfct_set_attr_u8(master, ATTR_L4PROTO, IPPROTO_TCP);
nfct_set_attr_u16(master, ATTR_PORT_SRC, htons(1025));
nfct_set_attr_u16(master, ATTR_PORT_DST, htons(21));
nfct_setobjopt(master, NFCT_SOPT_SETUP_REPLY);
nfct_set_attr_u8(master, ATTR_TCP_STATE, TCP_CONNTRACK_ESTABLISHED);
nfct_set_attr_u32(master, ATTR_TIMEOUT, 200);
h = nfct_open(CONNTRACK, 0);
if (!h) {
perror("nfct_open");
nfct_destroy(master);
return -1;
}
/*
* In a real scenario in which you want to implement an helper in
* user-space with NFQUEUE, the master conntrack does not need to
* be created, since it should already exist.
*/
ret = nfct_query(h, NFCT_Q_CREATE, master);
printf("TEST: add master conntrack ");
if (ret == -1)
printf("(%d)(%s)\n", ret, strerror(errno));
else
printf("(OK)\n");
nfct_close(h);
expected = nfct_new();
if (!expected) {
perror("nfct_new");
nfct_destroy(master);
exit(EXIT_FAILURE);
}
nfct_set_attr_u8(expected, ATTR_L3PROTO, AF_INET);
nfct_set_attr_u32(expected, ATTR_IPV4_SRC, inet_addr("1.1.1.1"));
nfct_set_attr_u32(expected, ATTR_IPV4_DST, inet_addr("2.2.2.2"));
nfct_set_attr_u8(expected, ATTR_L4PROTO, IPPROTO_TCP);
nfct_set_attr_u16(expected, ATTR_PORT_SRC, 0);
nfct_set_attr_u16(expected, ATTR_PORT_DST, htons(10241));
mask = nfct_new();
if (!mask) {
perror("nfct_new");
nfct_destroy(master);
nfct_destroy(expected);
exit(EXIT_FAILURE);
}
nfct_set_attr_u8(mask, ATTR_L3PROTO, AF_INET);
nfct_set_attr_u32(mask, ATTR_IPV4_SRC, 0xffffffff);
nfct_set_attr_u32(mask, ATTR_IPV4_DST, 0xffffffff);
nfct_set_attr_u8(mask, ATTR_L4PROTO, IPPROTO_TCP);
nfct_set_attr_u16(mask, ATTR_PORT_SRC, 0x0000);
nfct_set_attr_u16(mask, ATTR_PORT_DST, 0xffff);
/*
* Step 2: Setup expectation
*/
exp = nfexp_new();
if (!exp) {
perror("nfexp_new");
nfct_destroy(master);
nfct_destroy(expected);
nfct_destroy(mask);
exit(EXIT_FAILURE);
}
nfexp_set_attr(exp, ATTR_EXP_MASTER, master);
nfexp_set_attr(exp, ATTR_EXP_EXPECTED, expected);
nfexp_set_attr(exp, ATTR_EXP_MASK, mask);
nfexp_set_attr_u32(exp, ATTR_EXP_TIMEOUT, 200);
nfct_destroy(master);
nfct_destroy(expected);
nfct_destroy(mask);
h = nfct_open(EXPECT, 0);
if (!h) {
perror("nfct_open");
return -1;
}
ret = nfexp_query(h, NFCT_Q_CREATE, exp);
printf("TEST: create expectation ");
if (ret == -1)
printf("(%d)(%s)\n", ret, strerror(errno));
else
printf("(OK)\n");
nfct_close(h);
ret == -1 ? exit(EXIT_FAILURE) : exit(EXIT_SUCCESS);
}
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