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/*
* (C) 2005-2007 by Pablo Neira Ayuso <pablo@netfilter.org>
*
* 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 <stdio.h>
#include <getopt.h>
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h> /* For htons */
#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
#include <libnetfilter_conntrack/libnetfilter_conntrack_tcp.h>
#include "conntrack.h"
enum {
CT_TCP_ORIG_SPORT = (1 << 0),
CT_TCP_ORIG_DPORT = (1 << 1),
CT_TCP_REPL_SPORT = (1 << 2),
CT_TCP_REPL_DPORT = (1 << 3),
CT_TCP_MASK_SPORT = (1 << 4),
CT_TCP_MASK_DPORT = (1 << 5),
CT_TCP_STATE = (1 << 6),
CT_TCP_EXPTUPLE_SPORT = (1 << 7),
CT_TCP_EXPTUPLE_DPORT = (1 << 8)
};
static struct option opts[] = {
{"orig-port-src", 1, 0, '1'},
{"sport", 1, 0, '1'},
{"orig-port-dst", 1, 0, '2'},
{"dport", 1, 0, '2'},
{"reply-port-src", 1, 0, '3'},
{"reply-port-dst", 1, 0, '4'},
{"mask-port-src", 1, 0, '5'},
{"mask-port-dst", 1, 0, '6'},
{"state", 1, 0, '7'},
{"tuple-port-src", 1, 0, '8'},
{"tuple-port-dst", 1, 0, '9'},
{0, 0, 0, 0}
};
#define TCP_NUMBER_OF_OPT 10
static const char *tcp_optflags[TCP_NUMBER_OF_OPT] = {
"sport", "dport", "reply-port-src", "reply-port-dst", "mask-port-src",
"mask-port-dst", "state", "tuple-port-src", "tuple-port-dst"
};
static char tcp_commands_v_options[NUMBER_OF_CMD][TCP_NUMBER_OF_OPT] =
/* Well, it's better than "Re: Sevilla vs Betis" */
{
/* 1 2 3 4 5 6 7 8 9 */
/*CT_LIST*/ {2,2,2,2,0,0,2,0,0},
/*CT_CREATE*/ {3,3,3,3,0,0,1,0,0},
/*CT_UPDATE*/ {2,2,2,2,0,0,2,0,0},
/*CT_DELETE*/ {2,2,2,2,0,0,2,0,0},
/*CT_GET*/ {3,3,3,3,0,0,2,0,0},
/*CT_FLUSH*/ {0,0,0,0,0,0,0,0,0},
/*CT_EVENT*/ {2,2,2,2,0,0,2,0,0},
/*CT_VERSION*/ {0,0,0,0,0,0,0,0,0},
/*CT_HELP*/ {0,0,0,0,0,0,0,0,0},
/*EXP_LIST*/ {0,0,0,0,0,0,0,0,0},
/*EXP_CREATE*/ {1,1,1,1,1,1,0,1,1},
/*EXP_DELETE*/ {1,1,1,1,0,0,0,0,0},
/*EXP_GET*/ {1,1,1,1,0,0,0,0,0},
/*EXP_FLUSH*/ {0,0,0,0,0,0,0,0,0},
/*EXP_EVENT*/ {0,0,0,0,0,0,0,0,0},
};
static const char *tcp_states[TCP_CONNTRACK_MAX] = {
[TCP_CONNTRACK_NONE] = "NONE",
[TCP_CONNTRACK_SYN_SENT] = "SYN_SENT",
[TCP_CONNTRACK_SYN_RECV] = "SYN_RECV",
[TCP_CONNTRACK_ESTABLISHED] = "ESTABLISHED",
[TCP_CONNTRACK_FIN_WAIT] = "FIN_WAIT",
[TCP_CONNTRACK_CLOSE_WAIT] = "CLOSE_WAIT",
[TCP_CONNTRACK_LAST_ACK] = "LAST_ACK",
[TCP_CONNTRACK_TIME_WAIT] = "TIME_WAIT",
[TCP_CONNTRACK_CLOSE] = "CLOSE",
/* Since Linux kernel 2.6.31, LISTEN is SYN_SENT2. */
[TCP_CONNTRACK_SYN_SENT2] = "SYN_SENT2"
};
static void help(void)
{
fprintf(stdout, " --orig-port-src\t\toriginal source port\n");
fprintf(stdout, " --orig-port-dst\t\toriginal destination port\n");
fprintf(stdout, " --reply-port-src\t\treply source port\n");
fprintf(stdout, " --reply-port-dst\t\treply destination port\n");
fprintf(stdout, " --mask-port-src\t\tmask source port\n");
fprintf(stdout, " --mask-port-dst\t\tmask destination port\n");
fprintf(stdout, " --tuple-port-src\t\texpectation tuple src port\n");
fprintf(stdout, " --tuple-port-src\t\texpectation tuple dst port\n");
fprintf(stdout, " --state\t\t\tTCP state, fe. ESTABLISHED\n");
}
static int parse_options(char c,
struct nf_conntrack *ct,
struct nf_conntrack *exptuple,
struct nf_conntrack *mask,
unsigned int *flags)
{
int i;
u_int16_t port;
switch(c) {
case '1':
port = htons(atoi(optarg));
nfct_set_attr_u16(ct, ATTR_ORIG_PORT_SRC, port);
nfct_set_attr_u8(ct, ATTR_ORIG_L4PROTO, IPPROTO_TCP);
*flags |= CT_TCP_ORIG_SPORT;
break;
case '2':
port = htons(atoi(optarg));
nfct_set_attr_u16(ct, ATTR_ORIG_PORT_DST, port);
nfct_set_attr_u8(ct, ATTR_ORIG_L4PROTO, IPPROTO_TCP);
*flags |= CT_TCP_ORIG_DPORT;
break;
case '3':
port = htons(atoi(optarg));
nfct_set_attr_u16(ct, ATTR_REPL_PORT_SRC, port);
nfct_set_attr_u8(ct, ATTR_REPL_L4PROTO, IPPROTO_TCP);
*flags |= CT_TCP_REPL_SPORT;
break;
case '4':
port = htons(atoi(optarg));
nfct_set_attr_u16(ct, ATTR_REPL_PORT_DST, port);
nfct_set_attr_u8(ct, ATTR_REPL_L4PROTO, IPPROTO_TCP);
*flags |= CT_TCP_REPL_DPORT;
break;
case '5':
port = htons(atoi(optarg));
nfct_set_attr_u16(mask, ATTR_ORIG_PORT_SRC, port);
nfct_set_attr_u8(mask, ATTR_ORIG_L4PROTO, IPPROTO_TCP);
*flags |= CT_TCP_MASK_SPORT;
break;
case '6':
port = htons(atoi(optarg));
nfct_set_attr_u16(mask, ATTR_ORIG_PORT_DST, port);
nfct_set_attr_u8(mask, ATTR_ORIG_L4PROTO, IPPROTO_TCP);
*flags |= CT_TCP_MASK_DPORT;
break;
case '7':
for (i=0; i<TCP_CONNTRACK_MAX; i++) {
if (strcmp(optarg, tcp_states[i]) == 0) {
nfct_set_attr_u8(ct, ATTR_TCP_STATE, i);
break;
}
}
/* For backward compatibility with Linux kernel < 2.6.31. */
if (strcmp(optarg, "LISTEN") == 0) {
nfct_set_attr_u8(ct, ATTR_TCP_STATE,
TCP_CONNTRACK_LISTEN);
} else if (i == TCP_CONNTRACK_MAX)
exit_error(PARAMETER_PROBLEM,
"unknown TCP state `%s'", optarg);
*flags |= CT_TCP_STATE;
break;
case '8':
port = htons(atoi(optarg));
nfct_set_attr_u16(exptuple, ATTR_ORIG_PORT_SRC, port);
nfct_set_attr_u8(exptuple, ATTR_ORIG_L4PROTO, port);
*flags |= CT_TCP_EXPTUPLE_SPORT;
break;
case '9':
port = htons(atoi(optarg));
nfct_set_attr_u16(exptuple, ATTR_ORIG_PORT_DST, port);
nfct_set_attr_u8(exptuple, ATTR_ORIG_L4PROTO, port);
*flags |= CT_TCP_EXPTUPLE_DPORT;
break;
}
return 1;
}
#define TCP_VALID_FLAGS_MAX 2
static unsigned int tcp_valid_flags[TCP_VALID_FLAGS_MAX] = {
CT_TCP_ORIG_SPORT | CT_TCP_ORIG_DPORT,
CT_TCP_REPL_SPORT | CT_TCP_REPL_DPORT,
};
static void final_check(unsigned int flags,
unsigned int cmd,
struct nf_conntrack *ct)
{
int ret, partial;
ret = generic_opt_check(flags, TCP_NUMBER_OF_OPT,
tcp_commands_v_options[cmd], tcp_optflags,
tcp_valid_flags, TCP_VALID_FLAGS_MAX, &partial);
if (!ret) {
switch(partial) {
case -1:
case 0:
exit_error(PARAMETER_PROBLEM, "you have to specify "
"`--sport' and "
"`--dport'");
break;
case 1:
exit_error(PARAMETER_PROBLEM, "you have to specify "
"`--reply-src-port' and "
"`--reply-dst-port'");
break;
}
}
/* Disable TCP window tracking for manually created TCP entries,
* otherwise this will not work. */
uint8_t tcp_flags = IP_CT_TCP_FLAG_BE_LIBERAL |
IP_CT_TCP_FLAG_SACK_PERM;
/* This allows to reopen a new connection directly from TIME-WAIT
* as RFC 1122 states. See nf_conntrack_proto_tcp.c for more info. */
if (nfct_get_attr_u8(ct, ATTR_TCP_STATE) >= TCP_CONNTRACK_TIME_WAIT)
tcp_flags |= IP_CT_TCP_FLAG_CLOSE_INIT;
nfct_set_attr_u8(ct, ATTR_TCP_FLAGS_ORIG, tcp_flags);
nfct_set_attr_u8(ct, ATTR_TCP_MASK_ORIG, tcp_flags);
nfct_set_attr_u8(ct, ATTR_TCP_FLAGS_REPL, tcp_flags);
nfct_set_attr_u8(ct, ATTR_TCP_MASK_REPL, tcp_flags);
}
static struct ctproto_handler tcp = {
.name = "tcp",
.protonum = IPPROTO_TCP,
.parse_opts = parse_options,
.final_check = final_check,
.help = help,
.opts = opts,
.version = VERSION,
};
void register_tcp(void)
{
register_proto(&tcp);
}
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