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/*
* em_ipt.c IPtables extensions matching Ematch
*
* (C) 2018 Eyal Birger <eyal.birger@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <getopt.h>
#include <linux/tc_ematch/tc_em_ipt.h>
#include <linux/pkt_cls.h>
#include <xtables.h>
#include "m_ematch.h"
static void em_ipt_print_usage(FILE *fd)
{
fprintf(fd,
"Usage: ipt([-6] -m MATCH_NAME [MATCH_OPTS])\n"
"Example: 'ipt(-m policy --reqid 1 --pol ipsec --dir in)'\n");
}
static struct option original_opts[] = {
{
.name = "match",
.has_arg = 1,
.val = 'm'
},
{
.name = "ipv6",
.val = '6'
},
{}
};
static struct xtables_globals em_tc_ipt_globals = {
.option_offset = 0,
.program_name = "tc-em-ipt",
.program_version = "0.1",
.orig_opts = original_opts,
.opts = original_opts,
#if (XTABLES_VERSION_CODE >= 11)
.compat_rev = xtables_compatible_revision,
#endif
};
static struct xt_entry_match *fake_xt_entry_match(int data_size, void *data)
{
struct xt_entry_match *m;
m = xtables_calloc(1, XT_ALIGN(sizeof(*m)) + data_size);
if (!m)
return NULL;
if (data)
memcpy(m->data, data, data_size);
m->u.user.match_size = data_size;
return m;
}
static void scrub_match(struct xtables_match *match)
{
match->mflags = 0;
free(match->m);
match->m = NULL;
}
/* IPv4 and IPv6 share the same hooking enumeration */
#define HOOK_PRE_ROUTING 0
#define HOOK_POST_ROUTING 4
static __u32 em_ipt_hook(struct nlmsghdr *n)
{
struct tcmsg *t = NLMSG_DATA(n);
if (t->tcm_parent != TC_H_ROOT &&
t->tcm_parent == TC_H_MAJ(TC_H_INGRESS))
return HOOK_PRE_ROUTING;
return HOOK_POST_ROUTING;
}
static int em_ipt_parse_eopt_argv(struct nlmsghdr *n,
struct tcf_ematch_hdr *hdr,
int argc, char **argv)
{
struct xtables_globals tmp_tcipt_globals = em_tc_ipt_globals;
struct xtables_match *match = NULL;
__u8 nfproto = NFPROTO_IPV4;
while (1) {
struct option *opts;
int c;
c = getopt_long(argc, argv, "6m:", tmp_tcipt_globals.opts,
NULL);
if (c == -1)
break;
switch (c) {
case 'm':
xtables_init_all(&tmp_tcipt_globals, nfproto);
match = xtables_find_match(optarg, XTF_TRY_LOAD, NULL);
if (!match || !match->x6_parse) {
fprintf(stderr, " failed to find match %s\n\n",
optarg);
return -1;
}
match->m = fake_xt_entry_match(match->size, NULL);
if (!match->m) {
printf(" %s error\n", match->name);
return -1;
}
if (match->init)
match->init(match->m);
opts = xtables_options_xfrm(tmp_tcipt_globals.orig_opts,
tmp_tcipt_globals.opts,
match->x6_options,
&match->option_offset);
if (!opts) {
scrub_match(match);
return -1;
}
tmp_tcipt_globals.opts = opts;
break;
case '6':
nfproto = NFPROTO_IPV6;
break;
default:
if (!match) {
fprintf(stderr, "failed to find match %s\n\n",
optarg);
return -1;
}
xtables_option_mpcall(c, argv, 0, match, NULL);
break;
}
}
if (!match) {
fprintf(stderr, " failed to parse parameters (%s)\n", *argv);
return -1;
}
/* check that we passed the correct parameters to the match */
xtables_option_mfcall(match);
addraw_l(n, MAX_MSG, hdr, sizeof(*hdr));
addattr32(n, MAX_MSG, TCA_EM_IPT_HOOK, em_ipt_hook(n));
addattrstrz(n, MAX_MSG, TCA_EM_IPT_MATCH_NAME, match->name);
addattr8(n, MAX_MSG, TCA_EM_IPT_MATCH_REVISION, match->revision);
addattr8(n, MAX_MSG, TCA_EM_IPT_NFPROTO, nfproto);
addattr_l(n, MAX_MSG, TCA_EM_IPT_MATCH_DATA, match->m->data,
match->size);
xtables_free_opts(1);
scrub_match(match);
return 0;
}
static int em_ipt_print_epot(FILE *fd, struct tcf_ematch_hdr *hdr, void *data,
int data_len)
{
struct rtattr *tb[TCA_EM_IPT_MAX + 1];
struct xtables_match *match;
const char *mname;
__u8 nfproto;
if (parse_rtattr(tb, TCA_EM_IPT_MAX, data, data_len) < 0)
return -1;
nfproto = rta_getattr_u8(tb[TCA_EM_IPT_NFPROTO]);
xtables_init_all(&em_tc_ipt_globals, nfproto);
mname = rta_getattr_str(tb[TCA_EM_IPT_MATCH_NAME]);
match = xtables_find_match(mname, XTF_TRY_LOAD, NULL);
if (!match)
return -1;
match->m = fake_xt_entry_match(RTA_PAYLOAD(tb[TCA_EM_IPT_MATCH_DATA]),
RTA_DATA(tb[TCA_EM_IPT_MATCH_DATA]));
if (!match->m)
return -1;
match->print(NULL, match->m, 0);
scrub_match(match);
return 0;
}
struct ematch_util ipt_ematch_util = {
.kind = "ipt",
.kind_num = TCF_EM_IPT,
.parse_eopt_argv = em_ipt_parse_eopt_argv,
.print_eopt = em_ipt_print_epot,
.print_usage = em_ipt_print_usage
};
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