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