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/* Shared library add-on to iptables for DCCP matching
*
* (C) 2005 by Harald Welte <laforge@netfilter.org>
*
* This program is distributed under the terms of GNU GPL v2, 1991
*
*/
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <xtables.h>
#include <linux/dccp.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_dccp.h>
#if 0
#define DEBUGP(format, first...) printf(format, ##first)
#define static
#else
#define DEBUGP(format, fist...)
#endif
enum {
O_SOURCE_PORT = 0,
O_DEST_PORT,
O_DCCP_TYPES,
O_DCCP_OPTION,
};
static void dccp_help(void)
{
printf(
"dccp match options\n"
"[!] --source-port port[:port] match source port(s)\n"
" --sport ...\n"
"[!] --destination-port port[:port] match destination port(s)\n"
" --dport ...\n"
"[!] --dccp-types type[,...] match when packet is one of the given types\n"
"[!] --dccp-option option match if option (by number!) is set\n"
);
}
#define s struct xt_dccp_info
static const struct xt_option_entry dccp_opts[] = {
{.name = "source-port", .id = O_SOURCE_PORT, .type = XTTYPE_PORTRC,
.flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, spts)},
{.name = "sport", .id = O_SOURCE_PORT, .type = XTTYPE_PORTRC,
.flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, spts)},
{.name = "destination-port", .id = O_DEST_PORT, .type = XTTYPE_PORTRC,
.flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, dpts)},
{.name = "dport", .id = O_DEST_PORT, .type = XTTYPE_PORTRC,
.flags = XTOPT_INVERT | XTOPT_PUT, XTOPT_POINTER(s, dpts)},
{.name = "dccp-types", .id = O_DCCP_TYPES, .type = XTTYPE_STRING,
.flags = XTOPT_INVERT},
{.name = "dccp-option", .id = O_DCCP_OPTION, .type = XTTYPE_UINT8,
.min = 1, .max = UINT8_MAX, .flags = XTOPT_INVERT | XTOPT_PUT,
XTOPT_POINTER(s, option)},
XTOPT_TABLEEND,
};
#undef s
static const char *const dccp_pkt_types[] = {
[DCCP_PKT_REQUEST] = "REQUEST",
[DCCP_PKT_RESPONSE] = "RESPONSE",
[DCCP_PKT_DATA] = "DATA",
[DCCP_PKT_ACK] = "ACK",
[DCCP_PKT_DATAACK] = "DATAACK",
[DCCP_PKT_CLOSEREQ] = "CLOSEREQ",
[DCCP_PKT_CLOSE] = "CLOSE",
[DCCP_PKT_RESET] = "RESET",
[DCCP_PKT_SYNC] = "SYNC",
[DCCP_PKT_SYNCACK] = "SYNCACK",
[DCCP_PKT_INVALID] = "INVALID",
};
/* Bits for type values 11-15 */
#define INVALID_OTHER_TYPE_MASK 0xf800
static uint16_t
parse_dccp_types(const char *typestring)
{
uint16_t typemask = 0;
char *ptr, *buffer;
buffer = strdup(typestring);
for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) {
unsigned int i;
for (i = 0; i < ARRAY_SIZE(dccp_pkt_types); ++i)
if (!strcasecmp(dccp_pkt_types[i], ptr)) {
typemask |= (1 << i);
break;
}
if (i == ARRAY_SIZE(dccp_pkt_types))
xtables_error(PARAMETER_PROBLEM,
"Unknown DCCP type `%s'", ptr);
}
if (typemask & (1 << DCCP_PKT_INVALID))
typemask |= INVALID_OTHER_TYPE_MASK;
free(buffer);
return typemask;
}
static void dccp_parse(struct xt_option_call *cb)
{
struct xt_dccp_info *einfo = cb->data;
xtables_option_parse(cb);
switch (cb->entry->id) {
case O_SOURCE_PORT:
einfo->flags |= XT_DCCP_SRC_PORTS;
if (cb->invert)
einfo->invflags |= XT_DCCP_SRC_PORTS;
break;
case O_DEST_PORT:
einfo->flags |= XT_DCCP_DEST_PORTS;
if (cb->invert)
einfo->invflags |= XT_DCCP_DEST_PORTS;
break;
case O_DCCP_TYPES:
einfo->flags |= XT_DCCP_TYPE;
einfo->typemask = parse_dccp_types(cb->arg);
if (cb->invert)
einfo->invflags |= XT_DCCP_TYPE;
break;
case O_DCCP_OPTION:
einfo->flags |= XT_DCCP_OPTION;
if (cb->invert)
einfo->invflags |= XT_DCCP_OPTION;
break;
}
}
static const char *
port_to_service(int port)
{
const struct servent *service;
if ((service = getservbyport(htons(port), "dccp")))
return service->s_name;
return NULL;
}
static void
print_port(uint16_t port, int numeric)
{
const char *service;
if (numeric || (service = port_to_service(port)) == NULL)
printf("%u", port);
else
printf("%s", service);
}
static void
print_ports(const char *name, uint16_t min, uint16_t max,
int invert, int numeric)
{
const char *inv = invert ? "!" : "";
if (min != 0 || max != 0xFFFF || invert) {
printf(" %s", name);
if (min == max) {
printf(":%s", inv);
print_port(min, numeric);
} else {
printf("s:%s", inv);
print_port(min, numeric);
printf(":");
print_port(max, numeric);
}
}
}
static void
print_types(uint16_t types, int inverted, int numeric)
{
int have_type = 0;
if (inverted)
printf(" !");
printf(" ");
while (types) {
unsigned int i;
for (i = 0; !(types & (1 << i)); i++);
if (have_type)
printf(",");
else
have_type = 1;
if (numeric)
printf("%u", i);
else {
printf("%s", dccp_pkt_types[i]);
if (i == DCCP_PKT_INVALID)
break;
}
types &= ~(1 << i);
}
}
static void
print_option(uint8_t option, int invert, int numeric)
{
if (option || invert)
printf(" option=%s%u", invert ? "!" : "", option);
}
static void
dccp_print(const void *ip, const struct xt_entry_match *match, int numeric)
{
const struct xt_dccp_info *einfo =
(const struct xt_dccp_info *)match->data;
printf(" dccp");
if (einfo->flags & XT_DCCP_SRC_PORTS) {
print_ports("spt", einfo->spts[0], einfo->spts[1],
einfo->invflags & XT_DCCP_SRC_PORTS,
numeric);
}
if (einfo->flags & XT_DCCP_DEST_PORTS) {
print_ports("dpt", einfo->dpts[0], einfo->dpts[1],
einfo->invflags & XT_DCCP_DEST_PORTS,
numeric);
}
if (einfo->flags & XT_DCCP_TYPE) {
print_types(einfo->typemask,
einfo->invflags & XT_DCCP_TYPE,
numeric);
}
if (einfo->flags & XT_DCCP_OPTION) {
print_option(einfo->option,
einfo->invflags & XT_DCCP_OPTION, numeric);
}
}
static void dccp_save(const void *ip, const struct xt_entry_match *match)
{
const struct xt_dccp_info *einfo =
(const struct xt_dccp_info *)match->data;
if (einfo->flags & XT_DCCP_SRC_PORTS) {
if (einfo->invflags & XT_DCCP_SRC_PORTS)
printf(" !");
if (einfo->spts[0] != einfo->spts[1])
printf(" --sport %u:%u",
einfo->spts[0], einfo->spts[1]);
else
printf(" --sport %u", einfo->spts[0]);
}
if (einfo->flags & XT_DCCP_DEST_PORTS) {
if (einfo->invflags & XT_DCCP_DEST_PORTS)
printf(" !");
if (einfo->dpts[0] != einfo->dpts[1])
printf(" --dport %u:%u",
einfo->dpts[0], einfo->dpts[1]);
else
printf(" --dport %u", einfo->dpts[0]);
}
if (einfo->flags & XT_DCCP_TYPE) {
printf("%s --dccp-types",
einfo->invflags & XT_DCCP_TYPE ? " !" : "");
print_types(einfo->typemask, false, 0);
}
if (einfo->flags & XT_DCCP_OPTION) {
printf("%s --dccp-option %u",
einfo->invflags & XT_DCCP_OPTION ? " !" : "",
einfo->option);
}
}
static const char *const dccp_pkt_types_xlate[] = {
[DCCP_PKT_REQUEST] = "request",
[DCCP_PKT_RESPONSE] = "response",
[DCCP_PKT_DATA] = "data",
[DCCP_PKT_ACK] = "ack",
[DCCP_PKT_DATAACK] = "dataack",
[DCCP_PKT_CLOSEREQ] = "closereq",
[DCCP_PKT_CLOSE] = "close",
[DCCP_PKT_RESET] = "reset",
[DCCP_PKT_SYNC] = "sync",
[DCCP_PKT_SYNCACK] = "syncack",
[DCCP_PKT_INVALID] = "10-15",
};
static int dccp_type_xlate(const struct xt_dccp_info *einfo,
struct xt_xlate *xl)
{
bool have_type = false, set_need = false;
uint16_t types = einfo->typemask;
if (types & INVALID_OTHER_TYPE_MASK) {
types &= ~INVALID_OTHER_TYPE_MASK;
types |= 1 << DCCP_PKT_INVALID;
}
if ((types != 0) && !(types == (types & -types))) {
xt_xlate_add(xl, "{");
set_need = true;
}
while (types) {
unsigned int i;
for (i = 0; !(types & (1 << i)); i++);
if (have_type)
xt_xlate_add(xl, ", ");
else
have_type = true;
xt_xlate_add(xl, "%s", dccp_pkt_types_xlate[i]);
types &= ~(1 << i);
}
if (set_need)
xt_xlate_add(xl, "}");
return 1;
}
static int dccp_xlate(struct xt_xlate *xl,
const struct xt_xlate_mt_params *params)
{
const struct xt_dccp_info *einfo =
(const struct xt_dccp_info *)params->match->data;
char *space = "";
int ret = 1;
if (einfo->flags & XT_DCCP_SRC_PORTS) {
xt_xlate_add(xl, "dccp sport%s %u",
einfo->invflags & XT_DCCP_SRC_PORTS ? " !=" : "",
einfo->spts[0]);
if (einfo->spts[0] != einfo->spts[1])
xt_xlate_add(xl, "-%u", einfo->spts[1]);
space = " ";
}
if (einfo->flags & XT_DCCP_DEST_PORTS) {
xt_xlate_add(xl, "%sdccp dport%s %u", space,
einfo->invflags & XT_DCCP_DEST_PORTS ? " !=" : "",
einfo->dpts[0]);
if (einfo->dpts[0] != einfo->dpts[1])
xt_xlate_add(xl, "-%u", einfo->dpts[1]);
space = " ";
}
if (einfo->flags & XT_DCCP_TYPE && einfo->typemask) {
xt_xlate_add(xl, "%sdccp type%s ", space,
einfo->invflags & XT_DCCP_TYPE ? " !=" : "");
ret = dccp_type_xlate(einfo, xl);
space = " ";
}
/* FIXME: no dccp option support in nftables yet */
if (einfo->flags & XT_DCCP_OPTION)
ret = 0;
return ret;
}
static struct xtables_match dccp_match = {
.name = "dccp",
.family = NFPROTO_UNSPEC,
.version = XTABLES_VERSION,
.size = XT_ALIGN(sizeof(struct xt_dccp_info)),
.userspacesize = XT_ALIGN(sizeof(struct xt_dccp_info)),
.help = dccp_help,
.print = dccp_print,
.save = dccp_save,
.x6_parse = dccp_parse,
.x6_options = dccp_opts,
.xlate = dccp_xlate,
};
void _init(void)
{
xtables_register_match(&dccp_match);
}