blob: 5dbc36f519141631161fca866cb78553052304ae [file] [log] [blame]
/* Shared library add-on to iptables for SCTP matching
*
* (C) 2003 by Harald Welte <laforge@gnumonks.org>
*
* This program is distributed under the terms of GNU GPL v2, 1991
*
* libipt_ecn.c borrowed heavily from libipt_dscp.c
*
*/
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <netdb.h>
#include <ctype.h>
#include <netinet/in.h>
#include <xtables.h>
#include <linux/netfilter/xt_sctp.h>
#if 0
#define DEBUGP(format, first...) printf(format, ##first)
#define static
#else
#define DEBUGP(format, fist...)
#endif
static void
print_chunk(uint32_t chunknum, int numeric);
static void sctp_init(struct xt_entry_match *m)
{
int i;
struct xt_sctp_info *einfo = (struct xt_sctp_info *)m->data;
for (i = 0; i < XT_NUM_SCTP_FLAGS; i++) {
einfo->flag_info[i].chunktype = -1;
}
}
static void sctp_help(void)
{
printf(
"sctp 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"
"[!] --chunk-types (all|any|none) (chunktype[:flags])+ match if all, any or none of\n"
" chunktypes are present\n"
"chunktypes - DATA INIT INIT_ACK SACK HEARTBEAT HEARTBEAT_ACK ABORT SHUTDOWN SHUTDOWN_ACK ERROR COOKIE_ECHO COOKIE_ACK ECN_ECNE ECN_CWR SHUTDOWN_COMPLETE ASCONF ASCONF_ACK FORWARD_TSN ALL NONE\n");
}
static const struct option sctp_opts[] = {
{.name = "source-port", .has_arg = true, .val = '1'},
{.name = "sport", .has_arg = true, .val = '1'},
{.name = "destination-port", .has_arg = true, .val = '2'},
{.name = "dport", .has_arg = true, .val = '2'},
{.name = "chunk-types", .has_arg = true, .val = '3'},
XT_GETOPT_TABLEEND,
};
static void
parse_sctp_ports(const char *portstring,
uint16_t *ports)
{
char *buffer;
char *cp;
buffer = strdup(portstring);
DEBUGP("%s\n", portstring);
if ((cp = strchr(buffer, ':')) == NULL) {
ports[0] = ports[1] = xtables_parse_port(buffer, "sctp");
}
else {
*cp = '\0';
cp++;
ports[0] = buffer[0] ? xtables_parse_port(buffer, "sctp") : 0;
ports[1] = cp[0] ? xtables_parse_port(cp, "sctp") : 0xFFFF;
if (ports[0] > ports[1])
xtables_error(PARAMETER_PROBLEM,
"invalid portrange (min > max)");
}
free(buffer);
}
struct sctp_chunk_names {
const char *name;
unsigned int chunk_type;
const char *valid_flags;
};
/*'ALL' and 'NONE' will be treated specially. */
static const struct sctp_chunk_names sctp_chunk_names[]
= { { .name = "DATA", .chunk_type = 0, .valid_flags = "----IUBE"},
{ .name = "INIT", .chunk_type = 1, .valid_flags = "--------"},
{ .name = "INIT_ACK", .chunk_type = 2, .valid_flags = "--------"},
{ .name = "SACK", .chunk_type = 3, .valid_flags = "--------"},
{ .name = "HEARTBEAT", .chunk_type = 4, .valid_flags = "--------"},
{ .name = "HEARTBEAT_ACK", .chunk_type = 5, .valid_flags = "--------"},
{ .name = "ABORT", .chunk_type = 6, .valid_flags = "-------T"},
{ .name = "SHUTDOWN", .chunk_type = 7, .valid_flags = "--------"},
{ .name = "SHUTDOWN_ACK", .chunk_type = 8, .valid_flags = "--------"},
{ .name = "ERROR", .chunk_type = 9, .valid_flags = "--------"},
{ .name = "COOKIE_ECHO", .chunk_type = 10, .valid_flags = "--------"},
{ .name = "COOKIE_ACK", .chunk_type = 11, .valid_flags = "--------"},
{ .name = "ECN_ECNE", .chunk_type = 12, .valid_flags = "--------"},
{ .name = "ECN_CWR", .chunk_type = 13, .valid_flags = "--------"},
{ .name = "SHUTDOWN_COMPLETE", .chunk_type = 14, .valid_flags = "-------T"},
{ .name = "ASCONF", .chunk_type = 193, .valid_flags = "--------"},
{ .name = "ASCONF_ACK", .chunk_type = 128, .valid_flags = "--------"},
{ .name = "FORWARD_TSN", .chunk_type = 192, .valid_flags = "--------"},
};
static void
save_chunk_flag_info(struct xt_sctp_flag_info *flag_info,
int *flag_count,
int chunktype,
int bit,
int set)
{
int i;
for (i = 0; i < *flag_count; i++) {
if (flag_info[i].chunktype == chunktype) {
DEBUGP("Previous match found\n");
flag_info[i].chunktype = chunktype;
flag_info[i].flag_mask |= (1 << bit);
if (set) {
flag_info[i].flag |= (1 << bit);
}
return;
}
}
if (*flag_count == XT_NUM_SCTP_FLAGS) {
xtables_error (PARAMETER_PROBLEM,
"Number of chunk types with flags exceeds currently allowed limit."
"Increasing this limit involves changing IPT_NUM_SCTP_FLAGS and"
"recompiling both the kernel space and user space modules\n");
}
flag_info[*flag_count].chunktype = chunktype;
flag_info[*flag_count].flag_mask |= (1 << bit);
if (set) {
flag_info[*flag_count].flag |= (1 << bit);
}
(*flag_count)++;
}
static void
parse_sctp_chunk(struct xt_sctp_info *einfo,
const char *chunks)
{
char *ptr;
char *buffer;
unsigned int i, j;
int found = 0;
char *chunk_flags;
buffer = strdup(chunks);
DEBUGP("Buffer: %s\n", buffer);
SCTP_CHUNKMAP_RESET(einfo->chunkmap);
if (!strcasecmp(buffer, "ALL")) {
SCTP_CHUNKMAP_SET_ALL(einfo->chunkmap);
goto out;
}
if (!strcasecmp(buffer, "NONE")) {
SCTP_CHUNKMAP_RESET(einfo->chunkmap);
goto out;
}
for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) {
found = 0;
DEBUGP("Next Chunk type %s\n", ptr);
if ((chunk_flags = strchr(ptr, ':')) != NULL) {
*chunk_flags++ = 0;
}
for (i = 0; i < ARRAY_SIZE(sctp_chunk_names); ++i)
if (strcasecmp(sctp_chunk_names[i].name, ptr) == 0) {
DEBUGP("Chunk num %d\n", sctp_chunk_names[i].chunk_type);
SCTP_CHUNKMAP_SET(einfo->chunkmap,
sctp_chunk_names[i].chunk_type);
found = 1;
break;
}
if (!found)
xtables_error(PARAMETER_PROBLEM,
"Unknown sctp chunk `%s'", ptr);
if (chunk_flags) {
DEBUGP("Chunk flags %s\n", chunk_flags);
for (j = 0; j < strlen(chunk_flags); j++) {
char *p;
int bit;
if ((p = strchr(sctp_chunk_names[i].valid_flags,
toupper(chunk_flags[j]))) != NULL) {
bit = p - sctp_chunk_names[i].valid_flags;
bit = 7 - bit;
save_chunk_flag_info(einfo->flag_info,
&(einfo->flag_count), i, bit,
isupper(chunk_flags[j]));
} else {
xtables_error(PARAMETER_PROBLEM,
"Invalid flags for chunk type %d\n", i);
}
}
}
}
out:
free(buffer);
}
static void
parse_sctp_chunks(struct xt_sctp_info *einfo,
const char *match_type,
const char *chunks)
{
DEBUGP("Match type: %s Chunks: %s\n", match_type, chunks);
if (!strcasecmp(match_type, "ANY")) {
einfo->chunk_match_type = SCTP_CHUNK_MATCH_ANY;
} else if (!strcasecmp(match_type, "ALL")) {
einfo->chunk_match_type = SCTP_CHUNK_MATCH_ALL;
} else if (!strcasecmp(match_type, "ONLY")) {
einfo->chunk_match_type = SCTP_CHUNK_MATCH_ONLY;
} else {
xtables_error (PARAMETER_PROBLEM,
"Match type has to be one of \"ALL\", \"ANY\" or \"ONLY\"");
}
SCTP_CHUNKMAP_RESET(einfo->chunkmap);
parse_sctp_chunk(einfo, chunks);
}
static int
sctp_parse(int c, char **argv, int invert, unsigned int *flags,
const void *entry, struct xt_entry_match **match)
{
struct xt_sctp_info *einfo
= (struct xt_sctp_info *)(*match)->data;
switch (c) {
case '1':
if (*flags & XT_SCTP_SRC_PORTS)
xtables_error(PARAMETER_PROBLEM,
"Only one `--source-port' allowed");
einfo->flags |= XT_SCTP_SRC_PORTS;
xtables_check_inverse(optarg, &invert, &optind, 0, argv);
parse_sctp_ports(optarg, einfo->spts);
if (invert)
einfo->invflags |= XT_SCTP_SRC_PORTS;
*flags |= XT_SCTP_SRC_PORTS;
break;
case '2':
if (*flags & XT_SCTP_DEST_PORTS)
xtables_error(PARAMETER_PROBLEM,
"Only one `--destination-port' allowed");
einfo->flags |= XT_SCTP_DEST_PORTS;
xtables_check_inverse(optarg, &invert, &optind, 0, argv);
parse_sctp_ports(optarg, einfo->dpts);
if (invert)
einfo->invflags |= XT_SCTP_DEST_PORTS;
*flags |= XT_SCTP_DEST_PORTS;
break;
case '3':
if (*flags & XT_SCTP_CHUNK_TYPES)
xtables_error(PARAMETER_PROBLEM,
"Only one `--chunk-types' allowed");
xtables_check_inverse(optarg, &invert, &optind, 0, argv);
if (!argv[optind]
|| argv[optind][0] == '-' || argv[optind][0] == '!')
xtables_error(PARAMETER_PROBLEM,
"--chunk-types requires two args");
einfo->flags |= XT_SCTP_CHUNK_TYPES;
parse_sctp_chunks(einfo, optarg, argv[optind]);
if (invert)
einfo->invflags |= XT_SCTP_CHUNK_TYPES;
optind++;
*flags |= XT_SCTP_CHUNK_TYPES;
break;
}
return 1;
}
static const char *
port_to_service(int port)
{
const struct servent *service;
if ((service = getservbyport(htons(port), "sctp")))
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_chunk_flags(uint32_t chunknum, uint8_t chunk_flags, uint8_t chunk_flags_mask)
{
int i;
DEBUGP("type: %d\tflags: %x\tflag mask: %x\n", chunknum, chunk_flags,
chunk_flags_mask);
if (chunk_flags_mask) {
printf(":");
}
for (i = 7; i >= 0; i--) {
if (chunk_flags_mask & (1 << i)) {
if (chunk_flags & (1 << i)) {
printf("%c", sctp_chunk_names[chunknum].valid_flags[7-i]);
} else {
printf("%c", tolower(sctp_chunk_names[chunknum].valid_flags[7-i]));
}
}
}
}
static void
print_chunk(uint32_t chunknum, int numeric)
{
if (numeric) {
printf("0x%04X", chunknum);
}
else {
int i;
for (i = 0; i < ARRAY_SIZE(sctp_chunk_names); ++i)
if (sctp_chunk_names[i].chunk_type == chunknum)
printf("%s", sctp_chunk_names[chunknum].name);
}
}
static void
print_chunks(const struct xt_sctp_info *einfo, int numeric)
{
uint32_t chunk_match_type = einfo->chunk_match_type;
const struct xt_sctp_flag_info *flag_info = einfo->flag_info;
int flag_count = einfo->flag_count;
int i, j;
int flag;
switch (chunk_match_type) {
case SCTP_CHUNK_MATCH_ANY: printf(" any"); break;
case SCTP_CHUNK_MATCH_ALL: printf(" all"); break;
case SCTP_CHUNK_MATCH_ONLY: printf(" only"); break;
default: printf("Never reach here\n"); break;
}
if (SCTP_CHUNKMAP_IS_CLEAR(einfo->chunkmap)) {
printf(" NONE");
goto out;
}
if (SCTP_CHUNKMAP_IS_ALL_SET(einfo->chunkmap)) {
printf(" ALL");
goto out;
}
flag = 0;
for (i = 0; i < 256; i++) {
if (SCTP_CHUNKMAP_IS_SET(einfo->chunkmap, i)) {
if (flag)
printf(",");
else
putchar(' ');
flag = 1;
print_chunk(i, numeric);
for (j = 0; j < flag_count; j++) {
if (flag_info[j].chunktype == i) {
print_chunk_flags(i, flag_info[j].flag,
flag_info[j].flag_mask);
}
}
}
}
out:
return;
}
static void
sctp_print(const void *ip, const struct xt_entry_match *match, int numeric)
{
const struct xt_sctp_info *einfo =
(const struct xt_sctp_info *)match->data;
printf(" sctp");
if (einfo->flags & XT_SCTP_SRC_PORTS) {
print_ports("spt", einfo->spts[0], einfo->spts[1],
einfo->invflags & XT_SCTP_SRC_PORTS,
numeric);
}
if (einfo->flags & XT_SCTP_DEST_PORTS) {
print_ports("dpt", einfo->dpts[0], einfo->dpts[1],
einfo->invflags & XT_SCTP_DEST_PORTS,
numeric);
}
if (einfo->flags & XT_SCTP_CHUNK_TYPES) {
/* FIXME: print_chunks() is used in save() where the printing of '!'
s taken care of, so we need to do that here as well */
if (einfo->invflags & XT_SCTP_CHUNK_TYPES) {
printf(" !");
}
print_chunks(einfo, numeric);
}
}
static void sctp_save(const void *ip, const struct xt_entry_match *match)
{
const struct xt_sctp_info *einfo =
(const struct xt_sctp_info *)match->data;
if (einfo->flags & XT_SCTP_SRC_PORTS) {
if (einfo->invflags & XT_SCTP_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_SCTP_DEST_PORTS) {
if (einfo->invflags & XT_SCTP_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_SCTP_CHUNK_TYPES) {
if (einfo->invflags & XT_SCTP_CHUNK_TYPES)
printf(" !");
printf(" --chunk-types");
print_chunks(einfo, 0);
}
}
static struct xtables_match sctp_match = {
.name = "sctp",
.family = NFPROTO_UNSPEC,
.version = XTABLES_VERSION,
.size = XT_ALIGN(sizeof(struct xt_sctp_info)),
.userspacesize = XT_ALIGN(sizeof(struct xt_sctp_info)),
.help = sctp_help,
.init = sctp_init,
.parse = sctp_parse,
.print = sctp_print,
.save = sctp_save,
.extra_opts = sctp_opts,
};
void _init(void)
{
xtables_register_match(&sctp_match);
}