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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 <stdlib.h>
#include <time.h>
#include <string.h>
#include <netinet/in.h>
#include <linux/netfilter.h>
#include <linux/netfilter/nf_tables.h>
#include <libmnl/libmnl.h>
#include <libnftnl/object.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 struct nftnl_obj *obj_parse(int argc, char *argv[])
{
struct nftnl_obj *t;
uint16_t family;
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]);
if (argc > 3)
nftnl_obj_set_str(t, NFTNL_OBJ_NAME, argv[3]);
return t;
}
static int obj_cb(const struct nlmsghdr *nlh, void *data)
{
uint32_t *type = data;
struct nftnl_obj *t;
char buf[4096];
t = nftnl_obj_alloc();
if (t == NULL) {
perror("OOM");
goto err;
}
if (nftnl_obj_nlmsg_parse(nlh, t) < 0) {
perror("nftnl_obj_nlmsg_parse");
goto err_free;
}
nftnl_obj_snprintf(buf, sizeof(buf), t, *type, 0);
printf("%s\n", buf);
err_free:
nftnl_obj_free(t);
err:
return MNL_CB_OK;
}
int main(int argc, char *argv[])
{
struct mnl_socket *nl;
char buf[MNL_SOCKET_BUFFER_SIZE];
struct nlmsghdr *nlh;
uint32_t portid, seq, family;
struct nftnl_obj *t;
int ret;
uint32_t type = NFTNL_OUTPUT_DEFAULT;
uint16_t flags = NLM_F_ACK;
if (argc < 3 || argc > 4) {
fprintf(stderr, "%s <family> <table> [<name>]\n", argv[0]);
return EXIT_FAILURE;
}
t = obj_parse(argc, argv);
if (t == NULL)
exit(EXIT_FAILURE);
family = nftnl_obj_get_u32(t, NFTNL_OBJ_FAMILY);
seq = time(NULL);
if (argc < 4)
flags = NLM_F_DUMP;
nlh = nftnl_nlmsg_build_hdr(buf, NFT_MSG_GETOBJ, family, flags, seq);
nftnl_obj_nlmsg_build_payload(nlh, t);
nftnl_obj_free(t);
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, nlh, nlh->nlmsg_len) < 0) {
perror("mnl_socket_send");
exit(EXIT_FAILURE);
}
ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
while (ret > 0) {
ret = mnl_cb_run(buf, ret, seq, portid, obj_cb, &type);
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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