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/* Shared library add-on to iptables to add devgroup matching support.
*
* Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <xtables.h>
#include <linux/netfilter/xt_devgroup.h>
static void devgroup_help(void)
{
printf(
"devgroup match options:\n"
"[!] --src-group value[/mask] Match device group of incoming device\n"
"[!] --dst-group value[/mask] Match device group of outgoing device\n"
);
}
enum {
O_SRC_GROUP = 0,
O_DST_GROUP,
};
static const struct xt_option_entry devgroup_opts[] = {
{.name = "src-group", .id = O_SRC_GROUP, .type = XTTYPE_STRING,
.flags = XTOPT_INVERT},
{.name = "dst-group", .id = O_DST_GROUP, .type = XTTYPE_STRING,
.flags = XTOPT_INVERT},
XTOPT_TABLEEND,
};
/* array of devgroups from /etc/iproute2/group_map */
static struct xtables_lmap *devgroups;
static void devgroup_init(struct xt_entry_match *match)
{
const char file[] = "/etc/iproute2/group_map";
devgroups = xtables_lmap_init(file);
if (devgroups == NULL && errno != ENOENT)
fprintf(stderr, "Warning: %s: %s\n", file, strerror(errno));
}
static void devgroup_parse(struct xt_option_call *cb)
{
struct xt_devgroup_info *info = cb->data;
unsigned int id;
char *end;
xtables_option_parse(cb);
switch (cb->entry->id) {
case O_SRC_GROUP:
info->src_group = strtoul(cb->arg, &end, 0);
if (end != cb->arg && (*end == '/' || *end == '\0')) {
if (*end == '/')
info->src_mask = strtoul(end+1, &end, 0);
else
info->src_mask = 0xffffffff;
if (*end != '\0' || end == cb->arg)
xtables_error(PARAMETER_PROBLEM,
"Bad src-group value `%s'",
cb->arg);
} else {
id = xtables_lmap_name2id(devgroups, cb->arg);
if (id == -1)
xtables_error(PARAMETER_PROBLEM,
"Device group `%s' not found",
cb->arg);
info->src_group = id;
info->src_mask = 0xffffffff;
}
info->flags |= XT_DEVGROUP_MATCH_SRC;
if (cb->invert)
info->flags |= XT_DEVGROUP_INVERT_SRC;
break;
case O_DST_GROUP:
info->dst_group = strtoul(cb->arg, &end, 0);
if (end != cb->arg && (*end == '/' || *end == '\0')) {
if (*end == '/')
info->dst_mask = strtoul(end+1, &end, 0);
else
info->dst_mask = 0xffffffff;
if (*end != '\0' || end == cb->arg)
xtables_error(PARAMETER_PROBLEM,
"Bad dst-group value `%s'",
cb->arg);
} else {
id = xtables_lmap_name2id(devgroups, cb->arg);
if (id == -1)
xtables_error(PARAMETER_PROBLEM,
"Device group `%s' not found",
cb->arg);
info->dst_group = id;
info->dst_mask = 0xffffffff;
}
info->flags |= XT_DEVGROUP_MATCH_DST;
if (cb->invert)
info->flags |= XT_DEVGROUP_INVERT_DST;
break;
}
}
static void
print_devgroup(unsigned int id, unsigned int mask, int numeric)
{
const char *name = NULL;
if (mask != 0xffffffff)
printf("0x%x/0x%x", id, mask);
else {
if (numeric == 0)
name = xtables_lmap_id2name(devgroups, id);
if (name)
printf("%s", name);
else
printf("0x%x", id);
}
}
static void devgroup_show(const char *pfx, const struct xt_devgroup_info *info,
int numeric)
{
if (info->flags & XT_DEVGROUP_MATCH_SRC) {
if (info->flags & XT_DEVGROUP_INVERT_SRC)
printf(" !");
printf(" %ssrc-group ", pfx);
print_devgroup(info->src_group, info->src_mask, numeric);
}
if (info->flags & XT_DEVGROUP_MATCH_DST) {
if (info->flags & XT_DEVGROUP_INVERT_DST)
printf(" !");
printf(" %sdst-group ", pfx);
print_devgroup(info->src_group, info->src_mask, numeric);
}
}
static void devgroup_print(const void *ip, const struct xt_entry_match *match,
int numeric)
{
const struct xt_devgroup_info *info = (const void *)match->data;
devgroup_show("", info, numeric);
}
static void devgroup_save(const void *ip, const struct xt_entry_match *match)
{
const struct xt_devgroup_info *info = (const void *)match->data;
devgroup_show("--", info, 0);
}
static void devgroup_check(struct xt_fcheck_call *cb)
{
if (cb->xflags == 0)
xtables_error(PARAMETER_PROBLEM,
"devgroup match: You must specify either "
"'--src-group' or '--dst-group'");
}
static struct xtables_match devgroup_mt_reg = {
.name = "devgroup",
.version = XTABLES_VERSION,
.family = NFPROTO_UNSPEC,
.size = XT_ALIGN(sizeof(struct xt_devgroup_info)),
.userspacesize = XT_ALIGN(sizeof(struct xt_devgroup_info)),
.init = devgroup_init,
.help = devgroup_help,
.print = devgroup_print,
.save = devgroup_save,
.x6_parse = devgroup_parse,
.x6_fcheck = devgroup_check,
.x6_options = devgroup_opts,
};
void _init(void)
{
xtables_register_match(&devgroup_mt_reg);
}
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