1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <unistd.h> 4 #include <arpa/inet.h> 5 6 #include <libmnl/libmnl.h> 7 #include <libnetfilter_conntrack/libnetfilter_conntrack.h> 8 9 static int data_cb(const struct nlmsghdr *nlh, void *data) 10 { 11 struct nf_expect *exp; 12 uint32_t type = NFCT_T_UNKNOWN; 13 char buf[4096]; 14 15 switch(nlh->nlmsg_type & 0xFF) { 16 case IPCTNL_MSG_EXP_NEW: 17 if (nlh->nlmsg_flags & (NLM_F_CREATE|NLM_F_EXCL)) 18 type = NFCT_T_NEW; 19 else 20 type = NFCT_T_UPDATE; 21 break; 22 case IPCTNL_MSG_EXP_DELETE: 23 type = NFCT_T_DESTROY; 24 break; 25 } 26 27 exp = nfexp_new(); 28 if (exp == NULL) 29 return MNL_CB_OK; 30 31 nfexp_nlmsg_parse(nlh, exp); 32 33 nfexp_snprintf(buf, sizeof(buf), exp, 34 type, NFCT_O_DEFAULT, 0); 35 printf("%s\n", buf); 36 37 nfexp_destroy(exp); 38 39 return MNL_CB_OK; 40 } 41 42 int main(void) 43 { 44 struct mnl_socket *nl; 45 char buf[MNL_SOCKET_BUFFER_SIZE]; 46 int ret; 47 48 nl = mnl_socket_open(NETLINK_NETFILTER); 49 if (nl == NULL) { 50 perror("mnl_socket_open"); 51 exit(EXIT_FAILURE); 52 } 53 54 if (mnl_socket_bind(nl, NF_NETLINK_CONNTRACK_EXP_NEW | 55 NF_NETLINK_CONNTRACK_EXP_UPDATE | 56 NF_NETLINK_CONNTRACK_EXP_DESTROY, 57 MNL_SOCKET_AUTOPID) < 0) { 58 perror("mnl_socket_bind"); 59 exit(EXIT_FAILURE); 60 } 61 62 while (1) { 63 ret = mnl_socket_recvfrom(nl, buf, sizeof(buf)); 64 if (ret == -1) { 65 perror("mnl_socket_recvfrom"); 66 exit(EXIT_FAILURE); 67 } 68 69 ret = mnl_cb_run(buf, ret, 0, 0, data_cb, NULL); 70 if (ret == -1) { 71 perror("mnl_cb_run"); 72 exit(EXIT_FAILURE); 73 } 74 } 75 76 mnl_socket_close(nl); 77 78 return 0; 79 } 80
