| #include <stdio.h> |
| #include <stdlib.h> |
| #include <unistd.h> |
| #include <string.h> |
| #include <time.h> |
| #include <arpa/inet.h> |
| |
| #include <libmnl/libmnl.h> |
| #include <linux/netfilter.h> |
| #include <linux/netfilter/nfnetlink.h> |
| |
| #include <linux/types.h> |
| #include <linux/netfilter/nfnetlink_queue.h> |
| |
| #include <libnetfilter_queue/libnetfilter_queue.h> |
| |
| static struct mnl_socket *nl; |
| |
| static struct nlmsghdr * |
| nfq_hdr_put(char *buf, int type, uint32_t queue_num) |
| { |
| struct nlmsghdr *nlh = mnl_nlmsg_put_header(buf); |
| nlh->nlmsg_type = (NFNL_SUBSYS_QUEUE << 8) | type; |
| nlh->nlmsg_flags = NLM_F_REQUEST; |
| |
| struct nfgenmsg *nfg = mnl_nlmsg_put_extra_header(nlh, sizeof(*nfg)); |
| nfg->nfgen_family = AF_UNSPEC; |
| nfg->version = NFNETLINK_V0; |
| nfg->res_id = htons(queue_num); |
| |
| return nlh; |
| } |
| |
| static int |
| nfq_send_verdict(int queue_num, uint32_t id) |
| { |
| char buf[MNL_SOCKET_BUFFER_SIZE]; |
| struct nlmsghdr *nlh; |
| int ret; |
| |
| nlh = nfq_hdr_put(buf, NFQNL_MSG_VERDICT, queue_num); |
| nfq_nlmsg_verdict_put(nlh, id, NF_ACCEPT); |
| |
| if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) { |
| perror("mnl_socket_send"); |
| exit(EXIT_FAILURE); |
| } |
| |
| return ret; |
| } |
| |
| static int queue_cb(const struct nlmsghdr *nlh, void *data) |
| { |
| struct nfqnl_msg_packet_hdr *ph = NULL; |
| struct nlattr *attr[NFQA_MAX+1]; |
| uint32_t id = 0; |
| struct nfgenmsg *nfg; |
| |
| if (nfq_nlmsg_parse(nlh, attr) < 0) { |
| perror("problems parsing"); |
| return MNL_CB_ERROR; |
| } |
| |
| nfg = mnl_nlmsg_get_payload(nlh); |
| |
| ph = (struct nfqnl_msg_packet_hdr *) |
| mnl_attr_get_payload(attr[NFQA_PACKET_HDR]); |
| if (ph == NULL) { |
| perror("problems retrieving metaheader"); |
| return MNL_CB_ERROR; |
| } |
| |
| id = ntohl(ph->packet_id); |
| |
| printf("packet received (id=%u hw=0x%04x hook=%u)\n", |
| id, ntohs(ph->hw_protocol), ph->hook); |
| |
| nfq_send_verdict(ntohs(nfg->res_id), id); |
| |
| return MNL_CB_OK; |
| } |
| |
| int main(int argc, char *argv[]) |
| { |
| char buf[MNL_SOCKET_BUFFER_SIZE]; |
| struct nlmsghdr *nlh; |
| int ret; |
| unsigned int portid, queue_num; |
| |
| if (argc != 2) { |
| printf("Usage: %s [queue_num]\n", argv[0]); |
| exit(EXIT_FAILURE); |
| } |
| queue_num = 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); |
| |
| nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, 0); |
| nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, NFQNL_CFG_CMD_PF_UNBIND); |
| |
| if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) { |
| perror("mnl_socket_send"); |
| exit(EXIT_FAILURE); |
| } |
| |
| nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, 0); |
| nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, NFQNL_CFG_CMD_PF_BIND); |
| |
| if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) { |
| perror("mnl_socket_send"); |
| exit(EXIT_FAILURE); |
| } |
| |
| nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, queue_num); |
| nfq_nlmsg_cfg_put_cmd(nlh, AF_INET, NFQNL_CFG_CMD_BIND); |
| |
| if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) { |
| perror("mnl_socket_send"); |
| exit(EXIT_FAILURE); |
| } |
| |
| nlh = nfq_hdr_put(buf, NFQNL_MSG_CONFIG, queue_num); |
| nfq_nlmsg_cfg_put_params(nlh, NFQNL_COPY_PACKET, 0xffff); |
| |
| if (mnl_socket_sendto(nl, nlh, nlh->nlmsg_len) < 0) { |
| perror("mnl_socket_send"); |
| 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, queue_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; |
| } |