1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <unistd.h> 4 #include <time.h> 5 #include <arpa/inet.h> 6 7 #include <libmnl/libmnl.h> 8 #include <libnetfilter_conntrack/libnetfilter_conntrack.h> 9 10 static int data_cb(const struct nlmsghdr *nlh, void *data) 11 { 12 struct nf_expect *exp; 13 uint32_t type = NFCT_T_UNKNOWN; 14 char buf[4096]; 15 16 exp = nfexp_new(); 17 if (exp == NULL) 18 return MNL_CB_OK; 19 20 if (nfexp_nlmsg_parse(nlh, exp) < 0) { 21 perror("failed to parse message from kernel"); 22 return MNL_CB_ERROR; 23 } 24 25 nfexp_snprintf(buf, sizeof(buf), exp, type, NFCT_O_DEFAULT, 0); 26 printf("%s\n", buf); 27 28 nfexp_destroy(exp); 29 30 return MNL_CB_OK; 31 } 32 33 int main(void) 34 { 35 struct mnl_socket *nl; 36 char buf[MNL_SOCKET_BUFFER_SIZE]; 37 struct nlmsghdr *nlh; 38 struct nfgenmsg *nfh; 39 uint32_t seq, portid; 40 int ret; 41 42 nl = mnl_socket_open(NETLINK_NETFILTER); 43 if (nl == NULL) { 44 perror("mnl_socket_open"); 45 exit(EXIT_FAILURE); 46 } 47 48 if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) { 49 perror("mnl_socket_bind"); 50 exit(EXIT_FAILURE); 51 } 52 53 portid = mnl_socket_get_portid(nl); 54 55 nlh = mnl_nlmsg_put_header(buf); 56 nlh->nlmsg_type = (NFNL_SUBSYS_CTNETLINK_EXP << 8) | IPCTNL_MSG_EXP_GET; 57 nlh->nlmsg_flags = NLM_F_REQUEST|NLM_F_DUMP|NLM_F_ACK; 58 nlh->nlmsg_seq = seq = time(NULL); 59 60 nfh = mnl_nlmsg_put_extra_header(nlh, sizeof(struct nfgenmsg)); 61 nfh->nfgen_family = AF_INET; 62 nfh->version = NFNETLINK_V0; 63 nfh->res_id = 0; 64 65 ret = mnl_socket_sendto(nl, nlh, nlh->nlmsg_len); 66 if (ret == -1) { 67 perror("mnl_socket_recvfrom"); 68 exit(EXIT_FAILURE); 69 } 70 71 ret = mnl_socket_recvfrom(nl, buf, sizeof(buf)); 72 while (1) { 73 ret = mnl_cb_run(buf, ret, seq, portid, data_cb, NULL); 74 if (ret <= MNL_CB_STOP) 75 break; 76 77 ret = mnl_socket_recvfrom(nl, buf, sizeof(buf)); 78 } 79 if (ret == -1) { 80 perror("mnl_socket_recvfrom"); 81 exit(EXIT_FAILURE); 82 } 83 84 mnl_socket_close(nl); 85 86 return 0; 87 } 88
