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/* This example is placed in the public domain. */
#include <stdio.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <linux/netfilter/nfnetlink_log.h>
#include <libmnl/libmnl.h>
#include <libnetfilter_log/libnetfilter_log.h>
static int log_cb(const struct nlmsghdr *nlh, void *data)
{
struct nlattr *attrs[NFULA_MAX + 1] = { NULL };
struct nfulnl_msg_packet_hdr *ph = NULL;
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;
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);
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);
}
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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