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#include <netinet/ip.h>
#include <netinet/tcp.h>
#include "proto.h"
#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
#define PRINT_CMP(...)
static void l4_tcp_ct_build_tuple(const uint8_t *pkt, struct nf_conntrack *ct)
{
const struct tcphdr *tcph = (const struct tcphdr *)pkt;
nfct_set_attr_u8(ct, ATTR_ORIG_L4PROTO, IPPROTO_TCP);
nfct_set_attr_u8(ct, ATTR_REPL_L4PROTO, IPPROTO_TCP);
nfct_set_attr_u16(ct, ATTR_ORIG_PORT_SRC, tcph->source);
nfct_set_attr_u16(ct, ATTR_ORIG_PORT_DST, tcph->dest);
nfct_set_attr_u16(ct, ATTR_REPL_PORT_SRC, tcph->dest);
nfct_set_attr_u16(ct, ATTR_REPL_PORT_DST, tcph->source);
}
static int l4_tcp_ct_cmp_tuple_orig(const uint8_t *pkt, struct nf_conntrack *ct)
{
const struct tcphdr *tcph = (const struct tcphdr *)pkt;
PRINT_CMP("cmp_orig tcph->source: %u == %u\n",
tcph->source, nfct_get_attr_u16(ct, ATTR_ORIG_PORT_SRC));
PRINT_CMP("cmp_orig tcph->dest: %u == %u\n",
tcph->dest, nfct_get_attr_u16(ct, ATTR_ORIG_PORT_DST));
if (tcph->source == nfct_get_attr_u16(ct, ATTR_ORIG_PORT_SRC) &&
tcph->dest == nfct_get_attr_u16(ct, ATTR_ORIG_PORT_DST))
return 1;
return 0;
}
static int
l4_tcp_ct_cmp_tuple_repl(const uint8_t *pkt, struct nf_conntrack *ct)
{
const struct tcphdr *tcph = (const struct tcphdr *)pkt;
PRINT_CMP("cmp_repl tcph->source: %u == %u\n",
tcph->source, nfct_get_attr_u16(ct, ATTR_REPL_PORT_SRC));
PRINT_CMP("cmp_repl tcph->dest: %u == %u\n",
tcph->dest, nfct_get_attr_u16(ct, ATTR_REPL_PORT_DST));
if (tcph->source == nfct_get_attr_u16(ct, ATTR_REPL_PORT_SRC) &&
tcph->dest == nfct_get_attr_u16(ct, ATTR_REPL_PORT_DST))
return 1;
return 0;
}
static int
l4_tcp_ct_cmp_port(struct nf_conntrack *ct, uint16_t port)
{
PRINT_CMP("cmp_port src: %u == %u\n",
port, nfct_get_attr_u16(ct, ATTR_ORIG_PORT_SRC));
PRINT_CMP("cmp_port dst: %u == %u\n",
port, nfct_get_attr_u16(ct, ATTR_ORIG_PORT_DST));
if (port == nfct_get_attr_u16(ct, ATTR_ORIG_PORT_SRC) ||
port == nfct_get_attr_u16(ct, ATTR_ORIG_PORT_DST))
return 1;
return 0;
}
static int l4_tcp_pkt_no_data(const uint8_t *pkt)
{
const struct tcphdr *tcph = (const struct tcphdr *)pkt;
return tcph->syn || tcph->fin || tcph->rst || !tcph->psh;
}
static struct cthelper_proto_l4_helper tcp = {
.l4protonum = IPPROTO_TCP,
.l4ct_build = l4_tcp_ct_build_tuple,
.l4ct_cmp_orig = l4_tcp_ct_cmp_tuple_orig,
.l4ct_cmp_repl = l4_tcp_ct_cmp_tuple_repl,
.l4ct_cmp_port = l4_tcp_ct_cmp_port,
.l4pkt_no_data = l4_tcp_pkt_no_data,
};
void l4_tcp_init(void)
{
cthelper_proto_l4_helper_register(&tcp);
}
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