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/*
* (C) 2019 by Stéphane Veyret <sveyret@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published
* by the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <time.h>
#include <string.h>
#include <netinet/in.h>
#include <linux/netfilter.h>
#include <obj.h>
#include <libmnl/libmnl.h>
static uint16_t parse_family(char *str, const char *option)
{
if (strcmp(str, "ip") == 0)
return NFPROTO_IPV4;
else if (strcmp(str, "ip6") == 0)
return NFPROTO_IPV6;
else if (strcmp(str, "inet") == 0)
return NFPROTO_INET;
else if (strcmp(str, "arp") == 0)
return NFPROTO_INET;
fprintf(stderr, "Unknown %s: ip, ip6, inet, arp\n", option);
exit(EXIT_FAILURE);
}
static uint8_t parse_l4proto(char *str)
{
if (strcmp(str, "udp") == 0)
return IPPROTO_UDP;
else if (strcmp(str, "tcp") == 0)
return IPPROTO_TCP;
else {
fprintf(stderr, "Unknown l4proto: tcp, udp\n");
exit(EXIT_FAILURE);
}
return IPPROTO_TCP;
}
static struct nftnl_obj *obj_parse(int argc, char *argv[])
{
uint16_t family, l3proto, dport;
uint8_t l4proto, size;
struct nftnl_obj *t;
uint32_t timeout;
t = nftnl_obj_alloc();
if (t == NULL) {
perror("OOM");
return NULL;
}
family = parse_family(argv[1], "family");
nftnl_obj_set_u32(t, NFTNL_OBJ_FAMILY, family);
nftnl_obj_set_u32(t, NFTNL_OBJ_TYPE, NFT_OBJECT_CT_EXPECT);
nftnl_obj_set_str(t, NFTNL_OBJ_TABLE, argv[2]);
nftnl_obj_set_str(t, NFTNL_OBJ_NAME, argv[3]);
if (argc > 8) {
l3proto = parse_family(argv[8], "l3proto");
nftnl_obj_set_u16(t, NFTNL_OBJ_CT_EXPECT_L3PROTO, l3proto);
}
l4proto = parse_l4proto(argv[4]);
nftnl_obj_set_u8(t, NFTNL_OBJ_CT_EXPECT_L4PROTO, l4proto);
dport = atoi(argv[5]);
nftnl_obj_set_u16(t, NFTNL_OBJ_CT_EXPECT_DPORT, dport);
timeout = atol(argv[6]);
nftnl_obj_set_u32(t, NFTNL_OBJ_CT_EXPECT_TIMEOUT, timeout);
size = atoi(argv[7]);
nftnl_obj_set_u8(t, NFTNL_OBJ_CT_EXPECT_SIZE, size);
return t;
}
int main(int argc, char *argv[])
{
uint32_t portid, seq, obj_seq, family;
char buf[MNL_SOCKET_BUFFER_SIZE];
struct mnl_nlmsg_batch *batch;
struct mnl_socket *nl;
struct nlmsghdr *nlh;
struct nftnl_obj *t;
int ret;
if (argc < 8 || argc > 9) {
fprintf(stderr, "%s <family> <table> <name> <l4proto> <dport> <timeout> <size> [l3proto]\n", argv[0]);
exit(EXIT_FAILURE);
}
t = obj_parse(argc, argv);
if (t == NULL) {
exit(EXIT_FAILURE);
}
seq = time(NULL);
batch = mnl_nlmsg_batch_start(buf, sizeof(buf));
nftnl_batch_begin(mnl_nlmsg_batch_current(batch), seq++);
mnl_nlmsg_batch_next(batch);
obj_seq = seq;
family = nftnl_obj_get_u32(t, NFTNL_OBJ_FAMILY);
nlh = nftnl_nlmsg_build_hdr(mnl_nlmsg_batch_current(batch),
NFT_MSG_NEWOBJ, family,
NLM_F_ACK | NLM_F_CREATE, seq++);
nftnl_obj_nlmsg_build_payload(nlh, t);
nftnl_obj_free(t);
mnl_nlmsg_batch_next(batch);
nftnl_batch_end(mnl_nlmsg_batch_current(batch), seq++);
mnl_nlmsg_batch_next(batch);
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);
if (mnl_socket_sendto(nl, mnl_nlmsg_batch_head(batch),
mnl_nlmsg_batch_size(batch)) < 0) {
perror("mnl_socket_send");
exit(EXIT_FAILURE);
}
mnl_nlmsg_batch_stop(batch);
ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
while (ret > 0) {
ret = mnl_cb_run(buf, ret, obj_seq, portid, NULL, NULL);
if (ret <= 0)
break;
ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
}
if (ret == -1) {
perror("error");
exit(EXIT_FAILURE);
}
mnl_socket_close(nl);
return EXIT_SUCCESS;
}
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