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/* This example is placed in the public domain. */
#include <stdio.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <libnetfilter_log/linux_nfnetlink_log.h>
#include <libmnl/libmnl.h>
#include <libnetfilter_log/libnetfilter_log.h>
#ifdef BUILD_NFCT
#include <linux/netfilter/nf_conntrack_common.h>
#include <linux/netfilter/nf_conntrack_tuple_common.h>
#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
#endif
#ifdef BUILD_NFCT
static int print_ctinfo(const struct nlattr *const attr)
{
uint32_t ctinfo;
if (attr == NULL)
return MNL_CB_OK;
ctinfo = ntohl(mnl_attr_get_u32(attr));
printf(" ip_conntrack_info:");
switch (CTINFO2DIR(ctinfo)) {
case IP_CT_DIR_ORIGINAL:
printf(" ORIGINAL /");
break;
case IP_CT_DIR_REPLY:
printf(" REPLY /");
break;
default:
printf(" unknown dir: %d\n", CTINFO2DIR(ctinfo));
return MNL_CB_ERROR;
}
switch (ctinfo) {
case IP_CT_ESTABLISHED:
case IP_CT_ESTABLISHED_REPLY:
printf(" ESTABLISHED\n");
break;
case IP_CT_RELATED:
case IP_CT_RELATED_REPLY:
printf(" RELATED\n");
break;
case IP_CT_NEW:
case IP_CT_NEW_REPLY:
printf(" NEW\n");
break;
default:
printf(" unknown ctinfo: %d\n", ctinfo);
return MNL_CB_ERROR;
}
return MNL_CB_OK;
}
static int print_nfct(uint8_t family,
const struct nlattr *const info_attr,
const struct nlattr *const ct_attr)
{
char buf[4096];
struct nf_conntrack *ct = NULL;
if (info_attr != NULL)
print_ctinfo(info_attr);
if (ct_attr == NULL)
return MNL_CB_OK;
ct = nfct_new();
if (ct == NULL) {
perror("nfct_new");
return MNL_CB_ERROR;
}
if (nfct_payload_parse(mnl_attr_get_payload(ct_attr),
mnl_attr_get_payload_len(ct_attr),
family, ct) < 0) {
perror("nfct_payload_parse");
nfct_destroy(ct);
return MNL_CB_ERROR;
}
nfct_snprintf(buf, sizeof(buf), ct, 0, NFCT_O_DEFAULT, 0);
printf(" %s\n", buf);
nfct_destroy(ct);
return MNL_CB_OK;
}
#else
static int print_nfct(uint8_t family,
const struct nlattr *const info_attr,
const struct nlattr *const ct_attr)
{
return MNL_CB_OK;
}
#endif
static int log_cb(const struct nlmsghdr *nlh, void *data)
{
struct nlattr *attrs[NFULA_MAX + 1] = { NULL };
struct nfulnl_msg_packet_hdr *ph = NULL;
struct nfgenmsg *nfg;
const char *prefix = NULL;
uint32_t mark = 0;
char buf[4096];
int ret;
ret = nflog_nlmsg_parse(nlh, attrs);
if (ret != MNL_CB_OK)
return ret;
nfg = mnl_nlmsg_get_payload(nlh);
if (attrs[NFULA_PACKET_HDR])
ph = mnl_attr_get_payload(attrs[NFULA_PACKET_HDR]);
if (attrs[NFULA_PREFIX])
prefix = mnl_attr_get_str(attrs[NFULA_PREFIX]);
if (attrs[NFULA_MARK])
mark = ntohl(mnl_attr_get_u32(attrs[NFULA_MARK]));
printf("log received (prefix=\"%s\" hw=0x%04x hook=%u mark=%u)\n",
prefix ? prefix : "", ntohs(ph->hw_protocol), ph->hook,
mark);
ret = nflog_nlmsg_snprintf(buf, sizeof(buf), nlh, attrs,
NFLOG_OUTPUT_XML, NFLOG_XML_ALL);
if (ret < 0)
return MNL_CB_ERROR;
printf("%s (ret=%d)\n", buf, ret);
print_nfct(nfg->nfgen_family, attrs[NFULA_CT_INFO], attrs[NFULA_CT]);
return MNL_CB_OK;
}
int main(int argc, char *argv[])
{
struct mnl_socket *nl;
char buf[MNL_SOCKET_BUFFER_SIZE];
struct nlmsghdr *nlh;
int ret;
unsigned int portid, qnum;
if (argc != 2) {
printf("Usage: %s [queue_num]\n", argv[0]);
exit(EXIT_FAILURE);
}
qnum = atoi(argv[1]);
nl = mnl_socket_open(NETLINK_NETFILTER);
if (nl == NULL) {
perror("mnl_socket_open");
exit(EXIT_FAILURE);
}
if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
perror("mnl_socket_bind");
exit(EXIT_FAILURE);
}
portid = mnl_socket_get_portid(nl);
/* kernels 3.8 and later is required to omit PF_(UN)BIND */
nlh = nflog_nlmsg_put_header(buf, NFULNL_MSG_CONFIG, AF_INET, 0);
if (nflog_attr_put_cfg_cmd(nlh, NFULNL_CFG_CMD_PF_UNBIND) < 0) {
perror("nflog_attr_put_cfg_cmd");
exit(EXIT_FAILURE);
}
if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
perror("mnl_socket_sendto");
exit(EXIT_FAILURE);
}
nlh = nflog_nlmsg_put_header(buf, NFULNL_MSG_CONFIG, AF_INET, 0);
if (nflog_attr_put_cfg_cmd(nlh, NFULNL_CFG_CMD_PF_BIND) < 0) {
perror("nflog_attr_put_cfg_cmd");
exit(EXIT_FAILURE);
}
if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
perror("mnl_socket_sendto");
exit(EXIT_FAILURE);
}
nlh = nflog_nlmsg_put_header(buf, NFULNL_MSG_CONFIG, AF_INET, qnum);
if (nflog_attr_put_cfg_cmd(nlh, NFULNL_CFG_CMD_BIND) < 0) {
perror("nflog_attr_put_cfg_cmd");
exit(EXIT_FAILURE);
}
if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
perror("mnl_socket_sendto");
exit(EXIT_FAILURE);
}
nlh = nflog_nlmsg_put_header(buf, NFULNL_MSG_CONFIG, AF_UNSPEC, qnum);
if (nflog_attr_put_cfg_mode(nlh, NFULNL_COPY_PACKET, 0xffff) < 0) {
perror("nflog_attr_put_cfg_mode");
exit(EXIT_FAILURE);
}
#ifdef BUILD_NFCT
mnl_attr_put_u16(nlh, NFULA_CFG_FLAGS, htons(NFULNL_CFG_F_CONNTRACK));
#endif
if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) {
perror("mnl_socket_sendto");
exit(EXIT_FAILURE);
}
ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
if (ret == -1) {
perror("mnl_socket_recvfrom");
exit(EXIT_FAILURE);
}
while (ret > 0) {
ret = mnl_cb_run(buf, ret, 0, portid, log_cb, NULL);
if (ret < 0){
perror("mnl_cb_run");
exit(EXIT_FAILURE);
}
ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
if (ret == -1) {
perror("mnl_socket_recvfrom");
exit(EXIT_FAILURE);
}
}
mnl_socket_close(nl);
return 0;
}
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