16#include <netinet/in.h>
17#include <netinet/ip.h>
18#include <netinet/tcp.h>
21#include <sys/socket.h>
24#include <linux/netfilter.h>
25#include <linux/netfilter/nfnetlink.h>
26#include <linux/netfilter/nf_tables.h>
28#include <libmnl/libmnl.h>
29#include <libnftnl/rule.h>
30#include <libnftnl/expr.h>
32static void add_payload(
struct nftnl_rule *r, uint32_t base, uint32_t dreg,
33 uint32_t offset, uint32_t len)
37 e = nftnl_expr_alloc(
"payload");
39 perror(
"expr payload oom");
43 nftnl_expr_set_u32(e, NFTNL_EXPR_PAYLOAD_BASE, base);
44 nftnl_expr_set_u32(e, NFTNL_EXPR_PAYLOAD_DREG, dreg);
45 nftnl_expr_set_u32(e, NFTNL_EXPR_PAYLOAD_OFFSET, offset);
46 nftnl_expr_set_u32(e, NFTNL_EXPR_PAYLOAD_LEN, len);
48 nftnl_rule_add_expr(r, e);
51static void add_cmp(
struct nftnl_rule *r, uint32_t sreg, uint32_t op,
52 const void *data, uint32_t data_len)
56 e = nftnl_expr_alloc(
"cmp");
58 perror(
"expr cmp oom");
62 nftnl_expr_set_u32(e, NFTNL_EXPR_CMP_SREG, sreg);
63 nftnl_expr_set_u32(e, NFTNL_EXPR_CMP_OP, op);
64 nftnl_expr_set(e, NFTNL_EXPR_CMP_DATA, data, data_len);
66 nftnl_rule_add_expr(r, e);
69static void add_counter(
struct nftnl_rule *r)
73 e = nftnl_expr_alloc(
"counter");
75 perror(
"expr counter oom");
79 nftnl_rule_add_expr(r, e);
82static struct nftnl_rule *setup_rule(uint8_t family,
const char *table,
83 const char *chain,
const char *handle)
85 struct nftnl_rule *r = NULL;
90 r = nftnl_rule_alloc();
96 nftnl_rule_set_str(r, NFTNL_RULE_TABLE, table);
97 nftnl_rule_set_str(r, NFTNL_RULE_CHAIN, chain);
98 nftnl_rule_set_u32(r, NFTNL_RULE_FAMILY, family);
100 if (handle != NULL) {
101 handle_num = atoll(handle);
102 nftnl_rule_set_u64(r, NFTNL_RULE_POSITION, handle_num);
106 add_payload(r, NFT_PAYLOAD_NETWORK_HEADER, NFT_REG_1,
107 offsetof(
struct iphdr, protocol),
sizeof(uint8_t));
108 add_cmp(r, NFT_REG_1, NFT_CMP_EQ, &proto,
sizeof(uint8_t));
111 add_payload(r, NFT_PAYLOAD_TRANSPORT_HEADER, NFT_REG_1,
112 offsetof(
struct tcphdr, dest),
sizeof(uint16_t));
113 add_cmp(r, NFT_REG_1, NFT_CMP_EQ, &dport,
sizeof(uint16_t));
120int main(
int argc,
char *argv[])
122 struct mnl_socket *nl;
123 struct nftnl_rule *r;
124 struct nlmsghdr *nlh;
125 struct mnl_nlmsg_batch *batch;
127 char buf[MNL_SOCKET_BUFFER_SIZE];
128 uint32_t seq = time(NULL);
131 if (argc < 4 || argc > 5) {
132 fprintf(stderr,
"Usage: %s <family> <table> <chain>\n", argv[0]);
136 if (strcmp(argv[1],
"ip") == 0)
137 family = NFPROTO_IPV4;
138 else if (strcmp(argv[1],
"ip6") == 0)
139 family = NFPROTO_IPV6;
140 else if (strcmp(argv[1],
"inet") == 0)
141 family = NFPROTO_INET;
143 fprintf(stderr,
"Unknown family: ip, ip6, inet\n");
148 r = setup_rule(family, argv[2], argv[3], NULL);
150 r = setup_rule(family, argv[2], argv[3], argv[4]);
152 nl = mnl_socket_open(NETLINK_NETFILTER);
154 perror(
"mnl_socket_open");
158 if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {
159 perror(
"mnl_socket_bind");
163 batch = mnl_nlmsg_batch_start(buf,
sizeof(buf));
165 nftnl_batch_begin(mnl_nlmsg_batch_current(batch), seq++);
166 mnl_nlmsg_batch_next(batch);
168 nlh = nftnl_nlmsg_build_hdr(mnl_nlmsg_batch_current(batch),
170 nftnl_rule_get_u32(r, NFTNL_RULE_FAMILY),
171 NLM_F_APPEND | NLM_F_CREATE | NLM_F_ACK,
173 nftnl_rule_nlmsg_build_payload(nlh, r);
175 mnl_nlmsg_batch_next(batch);
177 nftnl_batch_end(mnl_nlmsg_batch_current(batch), seq++);
178 mnl_nlmsg_batch_next(batch);
180 ret = mnl_socket_sendto(nl, mnl_nlmsg_batch_head(batch),
181 mnl_nlmsg_batch_size(batch));
183 perror(
"mnl_socket_sendto");
187 mnl_nlmsg_batch_stop(batch);
189 ret = mnl_socket_recvfrom(nl, buf,
sizeof(buf));
191 perror(
"mnl_socket_recvfrom");
195 ret = mnl_cb_run(buf, ret, 0, mnl_socket_get_portid(nl), NULL, NULL);
197 perror(
"mnl_cb_run");
201 mnl_socket_close(nl);