Annotation of embedaddon/strongswan/src/libcharon/sa/ikev2/tasks/ike_natd.c, revision 1.1
1.1 ! misho 1: /*
! 2: * Copyright (C) 2006-2007 Martin Willi
! 3: * Copyright (C) 2006 Tobias Brunner, Daniel Roethlisberger
! 4: * HSR Hochschule fuer Technik Rapperswil
! 5: *
! 6: * This program is free software; you can redistribute it and/or modify it
! 7: * under the terms of the GNU General Public License as published by the
! 8: * Free Software Foundation; either version 2 of the License, or (at your
! 9: * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
! 10: *
! 11: * This program is distributed in the hope that it will be useful, but
! 12: * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
! 13: * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
! 14: * for more details.
! 15: */
! 16:
! 17: #include "ike_natd.h"
! 18:
! 19: #include <string.h>
! 20:
! 21: #include <daemon.h>
! 22: #include <config/peer_cfg.h>
! 23: #include <crypto/hashers/hasher.h>
! 24: #include <encoding/payloads/notify_payload.h>
! 25:
! 26:
! 27: typedef struct private_ike_natd_t private_ike_natd_t;
! 28:
! 29: /**
! 30: * Private members of a ike_natd_t task.
! 31: */
! 32: struct private_ike_natd_t {
! 33:
! 34: /**
! 35: * Public methods and task_t interface.
! 36: */
! 37: ike_natd_t public;
! 38:
! 39: /**
! 40: * Assigned IKE_SA.
! 41: */
! 42: ike_sa_t *ike_sa;
! 43:
! 44: /**
! 45: * Are we the initiator?
! 46: */
! 47: bool initiator;
! 48:
! 49: /**
! 50: * Hasher used to build NAT detection hashes
! 51: */
! 52: hasher_t *hasher;
! 53:
! 54: /**
! 55: * Did we process any NAT detection notifys for a source address?
! 56: */
! 57: bool src_seen;
! 58:
! 59: /**
! 60: * Did we process any NAT detection notifys for a destination address?
! 61: */
! 62: bool dst_seen;
! 63:
! 64: /**
! 65: * Have we found a matching source address NAT hash?
! 66: */
! 67: bool src_matched;
! 68:
! 69: /**
! 70: * Have we found a matching destination address NAT hash?
! 71: */
! 72: bool dst_matched;
! 73:
! 74: /**
! 75: * whether NAT mappings for our NATed address has changed
! 76: */
! 77: bool mapping_changed;
! 78: };
! 79:
! 80: /**
! 81: * Check if UDP encapsulation has to be forced either by config or required
! 82: * by the kernel interface
! 83: */
! 84: static bool force_encap(ike_cfg_t *ike_cfg)
! 85: {
! 86: if (!ike_cfg->force_encap(ike_cfg))
! 87: {
! 88: return charon->kernel->get_features(charon->kernel) &
! 89: KERNEL_REQUIRE_UDP_ENCAPSULATION;
! 90: }
! 91: return TRUE;
! 92: }
! 93:
! 94: /**
! 95: * Build NAT detection hash for a host
! 96: */
! 97: static chunk_t generate_natd_hash(private_ike_natd_t *this,
! 98: ike_sa_id_t *ike_sa_id, host_t *host)
! 99: {
! 100: chunk_t natd_chunk, spi_i_chunk, spi_r_chunk, addr_chunk, port_chunk;
! 101: chunk_t natd_hash;
! 102: uint64_t spi_i, spi_r;
! 103: uint16_t port;
! 104:
! 105: /* prepare all required chunks */
! 106: spi_i = ike_sa_id->get_initiator_spi(ike_sa_id);
! 107: spi_r = ike_sa_id->get_responder_spi(ike_sa_id);
! 108: spi_i_chunk.ptr = (void*)&spi_i;
! 109: spi_i_chunk.len = sizeof(spi_i);
! 110: spi_r_chunk.ptr = (void*)&spi_r;
! 111: spi_r_chunk.len = sizeof(spi_r);
! 112: port = htons(host->get_port(host));
! 113: port_chunk.ptr = (void*)&port;
! 114: port_chunk.len = sizeof(port);
! 115: addr_chunk = host->get_address(host);
! 116:
! 117: /* natd_hash = SHA1( spi_i | spi_r | address | port ) */
! 118: natd_chunk = chunk_cat("cccc", spi_i_chunk, spi_r_chunk, addr_chunk, port_chunk);
! 119: if (!this->hasher->allocate_hash(this->hasher, natd_chunk, &natd_hash))
! 120: {
! 121: natd_hash = chunk_empty;
! 122: }
! 123: DBG3(DBG_IKE, "natd_chunk %B", &natd_chunk);
! 124: DBG3(DBG_IKE, "natd_hash %B", &natd_hash);
! 125:
! 126: chunk_free(&natd_chunk);
! 127: return natd_hash;
! 128: }
! 129:
! 130: /**
! 131: * Build a NAT detection notify payload.
! 132: */
! 133: static notify_payload_t *build_natd_payload(private_ike_natd_t *this,
! 134: notify_type_t type, host_t *host)
! 135: {
! 136: chunk_t hash;
! 137: notify_payload_t *notify;
! 138: ike_sa_id_t *ike_sa_id;
! 139: ike_cfg_t *config;
! 140:
! 141: ike_sa_id = this->ike_sa->get_id(this->ike_sa);
! 142: config = this->ike_sa->get_ike_cfg(this->ike_sa);
! 143: if (force_encap(config) && type == NAT_DETECTION_SOURCE_IP)
! 144: {
! 145: uint32_t addr;
! 146:
! 147: /* chunk_hash() is randomly keyed so this produces a random IPv4 address
! 148: * that changes with every restart but otherwise stays the same */
! 149: addr = chunk_hash(chunk_from_chars(0x00, 0x00, 0x00, 0x00));
! 150: host = host_create_from_chunk(AF_INET, chunk_from_thing(addr), 0);
! 151: hash = generate_natd_hash(this, ike_sa_id, host);
! 152: host->destroy(host);
! 153: }
! 154: else
! 155: {
! 156: hash = generate_natd_hash(this, ike_sa_id, host);
! 157: }
! 158: if (!hash.len)
! 159: {
! 160: return NULL;
! 161: }
! 162: notify = notify_payload_create(PLV2_NOTIFY);
! 163: notify->set_notify_type(notify, type);
! 164: notify->set_notification_data(notify, hash);
! 165: chunk_free(&hash);
! 166:
! 167: return notify;
! 168: }
! 169:
! 170: /**
! 171: * read notifys from message and evaluate them
! 172: */
! 173: static void process_payloads(private_ike_natd_t *this, message_t *message)
! 174: {
! 175: enumerator_t *enumerator;
! 176: payload_t *payload;
! 177: notify_payload_t *notify;
! 178: chunk_t hash, src_hash, dst_hash;
! 179: ike_sa_id_t *ike_sa_id;
! 180: host_t *me, *other;
! 181: ike_cfg_t *config;
! 182:
! 183: /* Precompute NAT-D hashes for incoming NAT notify comparison */
! 184: ike_sa_id = message->get_ike_sa_id(message);
! 185: me = message->get_destination(message);
! 186: other = message->get_source(message);
! 187: dst_hash = generate_natd_hash(this, ike_sa_id, me);
! 188: src_hash = generate_natd_hash(this, ike_sa_id, other);
! 189:
! 190: DBG3(DBG_IKE, "precalculated src_hash %B", &src_hash);
! 191: DBG3(DBG_IKE, "precalculated dst_hash %B", &dst_hash);
! 192:
! 193: enumerator = message->create_payload_enumerator(message);
! 194: while (enumerator->enumerate(enumerator, &payload))
! 195: {
! 196: if (payload->get_type(payload) != PLV2_NOTIFY)
! 197: {
! 198: continue;
! 199: }
! 200: notify = (notify_payload_t*)payload;
! 201: switch (notify->get_notify_type(notify))
! 202: {
! 203: case NAT_DETECTION_DESTINATION_IP:
! 204: {
! 205: this->dst_seen = TRUE;
! 206: hash = notify->get_notification_data(notify);
! 207: if (!this->dst_matched)
! 208: {
! 209: DBG3(DBG_IKE, "received dst_hash %B", &hash);
! 210: if (chunk_equals(hash, dst_hash))
! 211: {
! 212: this->dst_matched = TRUE;
! 213: }
! 214: }
! 215: /* RFC4555 says we should also compare against IKE_SA_INIT
! 216: * NATD payloads, but this does not work: We are running
! 217: * there at port 500, but use 4500 afterwards... */
! 218: if (message->get_exchange_type(message) == INFORMATIONAL &&
! 219: this->initiator && !this->dst_matched)
! 220: {
! 221: this->mapping_changed = this->ike_sa->has_mapping_changed(
! 222: this->ike_sa, hash);
! 223: }
! 224: break;
! 225: }
! 226: case NAT_DETECTION_SOURCE_IP:
! 227: {
! 228: this->src_seen = TRUE;
! 229: if (!this->src_matched)
! 230: {
! 231: hash = notify->get_notification_data(notify);
! 232: DBG3(DBG_IKE, "received src_hash %B", &hash);
! 233: if (chunk_equals(hash, src_hash))
! 234: {
! 235: this->src_matched = TRUE;
! 236: }
! 237: }
! 238: break;
! 239: }
! 240: default:
! 241: break;
! 242: }
! 243: }
! 244: enumerator->destroy(enumerator);
! 245:
! 246: chunk_free(&src_hash);
! 247: chunk_free(&dst_hash);
! 248:
! 249: if (this->src_seen && this->dst_seen)
! 250: {
! 251: this->ike_sa->enable_extension(this->ike_sa, EXT_NATT);
! 252:
! 253: this->ike_sa->set_condition(this->ike_sa, COND_NAT_HERE,
! 254: !this->dst_matched);
! 255: this->ike_sa->set_condition(this->ike_sa, COND_NAT_THERE,
! 256: !this->src_matched);
! 257: config = this->ike_sa->get_ike_cfg(this->ike_sa);
! 258: if (this->dst_matched && this->src_matched &&
! 259: force_encap(config))
! 260: {
! 261: this->ike_sa->set_condition(this->ike_sa, COND_NAT_FAKE, TRUE);
! 262: }
! 263: }
! 264: }
! 265:
! 266: METHOD(task_t, process_i, status_t,
! 267: private_ike_natd_t *this, message_t *message)
! 268: {
! 269: process_payloads(this, message);
! 270:
! 271: if (message->get_exchange_type(message) == IKE_SA_INIT)
! 272: {
! 273: peer_cfg_t *peer_cfg = this->ike_sa->get_peer_cfg(this->ike_sa);
! 274: if (this->ike_sa->has_condition(this->ike_sa, COND_NAT_ANY) ||
! 275: /* if peer supports NAT-T, we switch to port 4500 even
! 276: * if no NAT is detected. can't be done later (when we would know
! 277: * whether the peer supports MOBIKE) because there would be no
! 278: * exchange to actually do the switch (other than a forced DPD). */
! 279: (peer_cfg->use_mobike(peer_cfg) &&
! 280: this->ike_sa->supports_extension(this->ike_sa, EXT_NATT)))
! 281: {
! 282: this->ike_sa->float_ports(this->ike_sa);
! 283: }
! 284: }
! 285:
! 286: return SUCCESS;
! 287: }
! 288:
! 289: METHOD(task_t, build_i, status_t,
! 290: private_ike_natd_t *this, message_t *message)
! 291: {
! 292: notify_payload_t *notify;
! 293: enumerator_t *enumerator;
! 294: ike_cfg_t *ike_cfg;
! 295: host_t *host;
! 296:
! 297: if (this->hasher == NULL)
! 298: {
! 299: DBG1(DBG_IKE, "unable to build NATD payloads, SHA1 not supported");
! 300: return NEED_MORE;
! 301: }
! 302:
! 303: ike_cfg = this->ike_sa->get_ike_cfg(this->ike_sa);
! 304:
! 305: /* destination is always set */
! 306: host = message->get_destination(message);
! 307: notify = build_natd_payload(this, NAT_DETECTION_DESTINATION_IP, host);
! 308: if (notify)
! 309: {
! 310: message->add_payload(message, (payload_t*)notify);
! 311: }
! 312:
! 313: /* source may be any, we have 3 possibilities to get our source address:
! 314: * 1. It is defined in the config => use the one of the IKE_SA
! 315: * 2. We do a routing lookup in the kernel interface
! 316: * 3. Include all possible addresses
! 317: */
! 318: host = message->get_source(message);
! 319: if (!host->is_anyaddr(host) || force_encap(ike_cfg))
! 320: { /* 1. or if we force UDP encap, as it doesn't matter if it's %any */
! 321: notify = build_natd_payload(this, NAT_DETECTION_SOURCE_IP, host);
! 322: if (notify)
! 323: {
! 324: message->add_payload(message, (payload_t*)notify);
! 325: }
! 326: }
! 327: else
! 328: {
! 329: host = charon->kernel->get_source_addr(charon->kernel,
! 330: this->ike_sa->get_other_host(this->ike_sa), NULL);
! 331: if (host)
! 332: { /* 2. */
! 333: host->set_port(host, ike_cfg->get_my_port(ike_cfg));
! 334: notify = build_natd_payload(this, NAT_DETECTION_SOURCE_IP, host);
! 335: if (notify)
! 336: {
! 337: message->add_payload(message, (payload_t*)notify);
! 338: }
! 339: host->destroy(host);
! 340: }
! 341: else
! 342: { /* 3. */
! 343: enumerator = charon->kernel->create_address_enumerator(
! 344: charon->kernel, ADDR_TYPE_REGULAR);
! 345: while (enumerator->enumerate(enumerator, (void**)&host))
! 346: {
! 347: /* apply port 500 to host, but work on a copy */
! 348: host = host->clone(host);
! 349: host->set_port(host, ike_cfg->get_my_port(ike_cfg));
! 350: notify = build_natd_payload(this, NAT_DETECTION_SOURCE_IP, host);
! 351: host->destroy(host);
! 352: if (notify)
! 353: {
! 354: message->add_payload(message, (payload_t*)notify);
! 355: }
! 356: }
! 357: enumerator->destroy(enumerator);
! 358: }
! 359: }
! 360: return NEED_MORE;
! 361: }
! 362:
! 363: METHOD(task_t, build_r, status_t,
! 364: private_ike_natd_t *this, message_t *message)
! 365: {
! 366: notify_payload_t *notify;
! 367: host_t *me, *other;
! 368:
! 369: /* only add notifies on successful responses. */
! 370: if (message->get_exchange_type(message) == IKE_SA_INIT &&
! 371: message->get_payload(message, PLV2_SECURITY_ASSOCIATION) == NULL)
! 372: {
! 373: return SUCCESS;
! 374: }
! 375:
! 376: if (this->src_seen && this->dst_seen)
! 377: {
! 378: if (this->hasher == NULL)
! 379: {
! 380: DBG1(DBG_IKE, "unable to build NATD payloads, SHA1 not supported");
! 381: return SUCCESS;
! 382: }
! 383:
! 384: /* initiator seems to support NAT detection, add response */
! 385: me = message->get_source(message);
! 386: notify = build_natd_payload(this, NAT_DETECTION_SOURCE_IP, me);
! 387: if (notify)
! 388: {
! 389: message->add_payload(message, (payload_t*)notify);
! 390: }
! 391: other = message->get_destination(message);
! 392: notify = build_natd_payload(this, NAT_DETECTION_DESTINATION_IP, other);
! 393: if (notify)
! 394: {
! 395: message->add_payload(message, (payload_t*)notify);
! 396: }
! 397: }
! 398: return SUCCESS;
! 399: }
! 400:
! 401: METHOD(task_t, process_r, status_t,
! 402: private_ike_natd_t *this, message_t *message)
! 403: {
! 404: process_payloads(this, message);
! 405:
! 406: return NEED_MORE;
! 407: }
! 408:
! 409: METHOD(task_t, get_type, task_type_t,
! 410: private_ike_natd_t *this)
! 411: {
! 412: return TASK_IKE_NATD;
! 413: }
! 414:
! 415: METHOD(task_t, migrate, void,
! 416: private_ike_natd_t *this, ike_sa_t *ike_sa)
! 417: {
! 418: this->ike_sa = ike_sa;
! 419: this->src_seen = FALSE;
! 420: this->dst_seen = FALSE;
! 421: this->src_matched = FALSE;
! 422: this->dst_matched = FALSE;
! 423: this->mapping_changed = FALSE;
! 424: }
! 425:
! 426: METHOD(task_t, destroy, void,
! 427: private_ike_natd_t *this)
! 428: {
! 429: DESTROY_IF(this->hasher);
! 430: free(this);
! 431: }
! 432:
! 433: METHOD(ike_natd_t, has_mapping_changed, bool,
! 434: private_ike_natd_t *this)
! 435: {
! 436: return this->mapping_changed;
! 437: }
! 438:
! 439: /*
! 440: * Described in header.
! 441: */
! 442: ike_natd_t *ike_natd_create(ike_sa_t *ike_sa, bool initiator)
! 443: {
! 444: private_ike_natd_t *this;
! 445:
! 446: INIT(this,
! 447: .public = {
! 448: .task = {
! 449: .get_type = _get_type,
! 450: .migrate = _migrate,
! 451: .destroy = _destroy,
! 452: },
! 453: .has_mapping_changed = _has_mapping_changed,
! 454: },
! 455: .ike_sa = ike_sa,
! 456: .initiator = initiator,
! 457: .hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA1),
! 458: );
! 459:
! 460: if (initiator)
! 461: {
! 462: this->public.task.build = _build_i;
! 463: this->public.task.process = _process_i;
! 464: }
! 465: else
! 466: {
! 467: this->public.task.build = _build_r;
! 468: this->public.task.process = _process_r;
! 469: }
! 470:
! 471: return &this->public;
! 472: }
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