netaddress.h raw
1 // Copyright (c) 2009-2022 The Limenka developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4
5 #ifndef LIMENKA_NETADDRESS_H
6 #define LIMENKA_NETADDRESS_H
7
8 #include <compat/compat.h>
9 #include <crypto/siphash.h>
10 #include <prevector.h>
11 #include <random.h>
12 #include <serialize.h>
13 #include <tinyformat.h>
14 #include <util/strencodings.h>
15 #include <util/string.h>
16
17 #include <array>
18 #include <cstdint>
19 #include <ios>
20 #include <string>
21 #include <vector>
22
23 /**
24 * A network type.
25 * @note An address may belong to more than one network, for example `10.0.0.1`
26 * belongs to both `NET_UNROUTABLE` and `NET_IPV4`.
27 * Keep these sequential starting from 0 and `NET_MAX` as the last entry.
28 * We have loops like `for (int i = 0; i < NET_MAX; ++i)` that expect to iterate
29 * over all enum values and also `GetExtNetwork()` "extends" this enum by
30 * introducing standalone constants starting from `NET_MAX`.
31 */
32 enum Network {
33 /// Addresses from these networks are not publicly routable on the global Internet.
34 NET_UNROUTABLE = 0,
35
36 /// IPv4
37 NET_IPV4,
38
39 /// IPv6
40 NET_IPV6,
41
42 /// TOR (v2 or v3)
43 NET_ONION,
44
45 /// I2P
46 NET_I2P,
47
48 /// CJDNS
49 NET_CJDNS,
50
51 /// A set of addresses that represent the hash of a string or FQDN. We use
52 /// them in AddrMan to keep track of which DNS seeds were used.
53 NET_INTERNAL,
54
55 /// Dummy value to indicate the number of NET_* constants.
56 NET_MAX,
57 };
58
59 /// Prefix of an IPv6 address when it contains an embedded IPv4 address.
60 /// Used when (un)serializing addresses in ADDRv1 format (pre-BIP155).
61 static const std::array<uint8_t, 12> IPV4_IN_IPV6_PREFIX{
62 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF};
63
64 /// Prefix of an IPv6 address when it contains an embedded TORv2 address.
65 /// Used when (un)serializing addresses in ADDRv1 format (pre-BIP155).
66 /// Such dummy IPv6 addresses are guaranteed to not be publicly routable as they
67 /// fall under RFC4193's fc00::/7 subnet allocated to unique-local addresses.
68 static const std::array<uint8_t, 6> TORV2_IN_IPV6_PREFIX{
69 0xFD, 0x87, 0xD8, 0x7E, 0xEB, 0x43};
70
71 /// Prefix of an IPv6 address when it contains an embedded "internal" address.
72 /// Used when (un)serializing addresses in ADDRv1 format (pre-BIP155).
73 /// The prefix comes from 0xFD + SHA256("limenka")[0:5].
74 /// Such dummy IPv6 addresses are guaranteed to not be publicly routable as they
75 /// fall under RFC4193's fc00::/7 subnet allocated to unique-local addresses.
76 static const std::array<uint8_t, 6> INTERNAL_IN_IPV6_PREFIX{
77 0xFD, 0x6B, 0x88, 0xC0, 0x87, 0x24 // 0xFD + sha256("limenka")[0:5].
78 };
79
80 /// All CJDNS addresses start with 0xFC. See
81 /// https://github.com/cjdelisle/cjdns/blob/master/doc/Whitepaper.md#pulling-it-all-together
82 static constexpr uint8_t CJDNS_PREFIX{0xFC};
83
84 /// Size of IPv4 address (in bytes).
85 static constexpr size_t ADDR_IPV4_SIZE = 4;
86
87 /// Size of IPv6 address (in bytes).
88 static constexpr size_t ADDR_IPV6_SIZE = 16;
89
90 /// Size of TORv3 address (in bytes). This is the length of just the address
91 /// as used in BIP155, without the checksum and the version byte.
92 static constexpr size_t ADDR_TORV3_SIZE = 32;
93
94 /// Size of I2P address (in bytes).
95 static constexpr size_t ADDR_I2P_SIZE = 32;
96
97 /// Size of CJDNS address (in bytes).
98 static constexpr size_t ADDR_CJDNS_SIZE = 16;
99
100 /// Size of "internal" (NET_INTERNAL) address (in bytes).
101 static constexpr size_t ADDR_INTERNAL_SIZE = 10;
102
103 /// SAM 3.1 and earlier do not support specifying ports and force the port to 0.
104 static constexpr uint16_t I2P_SAM31_PORT{0};
105
106 std::string OnionToString(Span<const uint8_t> addr);
107
108 /**
109 * Network address.
110 */
111 class CNetAddr
112 {
113 protected:
114 /**
115 * Raw representation of the network address.
116 * In network byte order (big endian) for IPv4 and IPv6.
117 */
118 prevector<ADDR_IPV6_SIZE, uint8_t> m_addr{ADDR_IPV6_SIZE, 0x0};
119
120 /**
121 * Network to which this address belongs.
122 */
123 Network m_net{NET_IPV6};
124
125 /**
126 * Scope id if scoped/link-local IPV6 address.
127 * See https://tools.ietf.org/html/rfc4007
128 */
129 uint32_t m_scope_id{0};
130
131 public:
132 CNetAddr();
133 explicit CNetAddr(const struct in_addr& ipv4Addr);
134 void SetIP(const CNetAddr& ip);
135
136 /**
137 * Set from a legacy IPv6 address.
138 * Legacy IPv6 address may be a normal IPv6 address, or another address
139 * (e.g. IPv4) disguised as IPv6. This encoding is used in the legacy
140 * `addr` encoding.
141 */
142 void SetLegacyIPv6(Span<const uint8_t> ipv6);
143
144 bool SetInternal(const std::string& name);
145
146 /**
147 * Parse a Tor or I2P address and set this object to it.
148 * @param[in] addr Address to parse, for example
149 * pg6mmjiyjmcrsslvykfwnntlaru7p5svn6y2ymmju6nubxndf4pscryd.onion or
150 * ukeu3k5oycgaauneqgtnvselmt4yemvoilkln7jpvamvfx7dnkdq.b32.i2p.
151 * @returns Whether the operation was successful.
152 * @see CNetAddr::IsTor(), CNetAddr::IsI2P()
153 */
154 bool SetSpecial(const std::string& addr);
155
156 bool IsBindAny() const; // INADDR_ANY equivalent
157 [[nodiscard]] bool IsIPv4() const { return m_net == NET_IPV4; } // IPv4 mapped address (::FFFF:0:0/96, 0.0.0.0/0)
158 [[nodiscard]] bool IsIPv6() const { return m_net == NET_IPV6; } // IPv6 address (not mapped IPv4, not Tor)
159 bool IsRFC1918() const; // IPv4 private networks (10.0.0.0/8, 192.168.0.0/16, 172.16.0.0/12)
160 bool IsRFC2544() const; // IPv4 inter-network communications (198.18.0.0/15)
161 bool IsRFC6598() const; // IPv4 ISP-level NAT (100.64.0.0/10)
162 bool IsRFC5737() const; // IPv4 documentation addresses (192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24)
163 bool IsRFC3849() const; // IPv6 documentation address (2001:0DB8::/32)
164 bool IsRFC3927() const; // IPv4 autoconfig (169.254.0.0/16)
165 bool IsRFC3964() const; // IPv6 6to4 tunnelling (2002::/16)
166 bool IsRFC4193() const; // IPv6 unique local (FC00::/7)
167 bool IsRFC4380() const; // IPv6 Teredo tunnelling (2001::/32)
168 bool IsRFC4843() const; // IPv6 ORCHID (deprecated) (2001:10::/28)
169 bool IsRFC7343() const; // IPv6 ORCHIDv2 (2001:20::/28)
170 bool IsRFC4862() const; // IPv6 autoconfig (FE80::/64)
171 bool IsRFC6052() const; // IPv6 well-known prefix for IPv4-embedded address (64:FF9B::/96)
172 bool IsRFC6145() const; // IPv6 IPv4-translated address (::FFFF:0:0:0/96) (actually defined in RFC2765)
173 bool IsHeNet() const; // IPv6 Hurricane Electric - https://he.net (2001:0470::/36)
174 [[nodiscard]] bool IsTor() const { return m_net == NET_ONION; }
175 [[nodiscard]] bool IsI2P() const { return m_net == NET_I2P; }
176 [[nodiscard]] bool IsCJDNS() const { return m_net == NET_CJDNS; }
177 [[nodiscard]] bool HasCJDNSPrefix() const { return m_addr[0] == CJDNS_PREFIX; }
178 bool IsLocal() const;
179 bool IsRoutable() const;
180 bool IsInternal() const;
181 bool IsValid() const;
182
183 /**
184 * Whether this object is a privacy network.
185 * TODO: consider adding IsCJDNS() here when more peers adopt CJDNS, see:
186 * https://github.com/limenka/limenka/pull/27411#issuecomment-1497176155
187 */
188 [[nodiscard]] bool IsPrivacyNet() const { return IsTor() || IsI2P(); }
189
190 /**
191 * Check if the current object can be serialized in pre-ADDRv2/BIP155 format.
192 */
193 bool IsAddrV1Compatible() const;
194
195 enum Network GetNetwork() const;
196 std::string ToStringAddr() const;
197 bool GetInAddr(struct in_addr* pipv4Addr) const;
198 Network GetNetClass() const;
199
200 //! For IPv4, mapped IPv4, SIIT translated IPv4, Teredo, 6to4 tunneled addresses, return the relevant IPv4 address as a uint32.
201 uint32_t GetLinkedIPv4() const;
202 //! Whether this address has a linked IPv4 address (see GetLinkedIPv4()).
203 bool HasLinkedIPv4() const;
204
205 std::vector<unsigned char> GetAddrBytes() const;
206 int GetReachabilityFrom(const CNetAddr& paddrPartner) const;
207
208 explicit CNetAddr(const struct in6_addr& pipv6Addr, const uint32_t scope = 0);
209 bool GetIn6Addr(struct in6_addr* pipv6Addr) const;
210
211 friend bool operator==(const CNetAddr& a, const CNetAddr& b);
212 friend bool operator!=(const CNetAddr& a, const CNetAddr& b) { return !(a == b); }
213 friend bool operator<(const CNetAddr& a, const CNetAddr& b);
214
215 /**
216 * Whether this address should be relayed to other peers even if we can't reach it ourselves.
217 */
218 bool IsRelayable() const
219 {
220 return IsIPv4() || IsIPv6() || IsTor() || IsI2P() || IsCJDNS();
221 }
222
223 enum class Encoding {
224 V1,
225 V2, //!< BIP155 encoding
226 };
227 struct SerParams {
228 const Encoding enc;
229 SER_PARAMS_OPFUNC
230 };
231 static constexpr SerParams V1{Encoding::V1};
232 static constexpr SerParams V2{Encoding::V2};
233
234 /**
235 * Serialize to a stream.
236 */
237 template <typename Stream>
238 void Serialize(Stream& s) const
239 {
240 if (s.template GetParams<SerParams>().enc == Encoding::V2) {
241 SerializeV2Stream(s);
242 } else {
243 SerializeV1Stream(s);
244 }
245 }
246
247 /**
248 * Unserialize from a stream.
249 */
250 template <typename Stream>
251 void Unserialize(Stream& s)
252 {
253 if (s.template GetParams<SerParams>().enc == Encoding::V2) {
254 UnserializeV2Stream(s);
255 } else {
256 UnserializeV1Stream(s);
257 }
258 }
259
260 /**
261 * BIP155 network ids recognized by this software.
262 */
263 enum BIP155Network : uint8_t {
264 IPV4 = 1,
265 IPV6 = 2,
266 TORV2 = 3,
267 TORV3 = 4,
268 I2P = 5,
269 CJDNS = 6,
270 };
271
272 friend class CSubNet;
273
274 private:
275 /**
276 * Parse a Tor address and set this object to it.
277 * @param[in] addr Address to parse, must be a valid C string, for example
278 * pg6mmjiyjmcrsslvykfwnntlaru7p5svn6y2ymmju6nubxndf4pscryd.onion.
279 * @returns Whether the operation was successful.
280 * @see CNetAddr::IsTor()
281 */
282 bool SetTor(const std::string& addr);
283
284 /**
285 * Parse an I2P address and set this object to it.
286 * @param[in] addr Address to parse, must be a valid C string, for example
287 * ukeu3k5oycgaauneqgtnvselmt4yemvoilkln7jpvamvfx7dnkdq.b32.i2p.
288 * @returns Whether the operation was successful.
289 * @see CNetAddr::IsI2P()
290 */
291 bool SetI2P(const std::string& addr);
292
293 /**
294 * Size of CNetAddr when serialized as ADDRv1 (pre-BIP155) (in bytes).
295 */
296 static constexpr size_t V1_SERIALIZATION_SIZE = ADDR_IPV6_SIZE;
297
298 /**
299 * Maximum size of an address as defined in BIP155 (in bytes).
300 * This is only the size of the address, not the entire CNetAddr object
301 * when serialized.
302 */
303 static constexpr size_t MAX_ADDRV2_SIZE = 512;
304
305 /**
306 * Get the BIP155 network id of this address.
307 * Must not be called for IsInternal() objects.
308 * @returns BIP155 network id, except TORV2 which is no longer supported.
309 */
310 BIP155Network GetBIP155Network() const;
311
312 /**
313 * Set `m_net` from the provided BIP155 network id and size after validation.
314 * @retval true the network was recognized, is valid and `m_net` was set
315 * @retval false not recognised (from future?) and should be silently ignored
316 * @throws std::ios_base::failure if the network is one of the BIP155 founding
317 * networks (id 1..6) with wrong address size.
318 */
319 bool SetNetFromBIP155Network(uint8_t possible_bip155_net, size_t address_size);
320
321 /**
322 * Serialize in pre-ADDRv2/BIP155 format to an array.
323 */
324 void SerializeV1Array(uint8_t (&arr)[V1_SERIALIZATION_SIZE]) const
325 {
326 size_t prefix_size;
327
328 switch (m_net) {
329 case NET_IPV6:
330 assert(m_addr.size() == sizeof(arr));
331 memcpy(arr, m_addr.data(), m_addr.size());
332 return;
333 case NET_IPV4:
334 prefix_size = sizeof(IPV4_IN_IPV6_PREFIX);
335 assert(prefix_size + m_addr.size() == sizeof(arr));
336 memcpy(arr, IPV4_IN_IPV6_PREFIX.data(), prefix_size);
337 memcpy(arr + prefix_size, m_addr.data(), m_addr.size());
338 return;
339 case NET_INTERNAL:
340 prefix_size = sizeof(INTERNAL_IN_IPV6_PREFIX);
341 assert(prefix_size + m_addr.size() == sizeof(arr));
342 memcpy(arr, INTERNAL_IN_IPV6_PREFIX.data(), prefix_size);
343 memcpy(arr + prefix_size, m_addr.data(), m_addr.size());
344 return;
345 case NET_ONION:
346 case NET_I2P:
347 case NET_CJDNS:
348 break;
349 case NET_UNROUTABLE:
350 case NET_MAX:
351 assert(false);
352 } // no default case, so the compiler can warn about missing cases
353
354 // Serialize ONION, I2P and CJDNS as all-zeros.
355 memset(arr, 0x0, V1_SERIALIZATION_SIZE);
356 }
357
358 /**
359 * Serialize in pre-ADDRv2/BIP155 format to a stream.
360 */
361 template <typename Stream>
362 void SerializeV1Stream(Stream& s) const
363 {
364 uint8_t serialized[V1_SERIALIZATION_SIZE];
365
366 SerializeV1Array(serialized);
367
368 s << serialized;
369 }
370
371 /**
372 * Serialize as ADDRv2 / BIP155.
373 */
374 template <typename Stream>
375 void SerializeV2Stream(Stream& s) const
376 {
377 if (IsInternal()) {
378 // Serialize NET_INTERNAL as embedded in IPv6. We need to
379 // serialize such addresses from addrman.
380 s << static_cast<uint8_t>(BIP155Network::IPV6);
381 s << COMPACTSIZE(ADDR_IPV6_SIZE);
382 SerializeV1Stream(s);
383 return;
384 }
385
386 s << static_cast<uint8_t>(GetBIP155Network());
387 s << m_addr;
388 }
389
390 /**
391 * Unserialize from a pre-ADDRv2/BIP155 format from an array.
392 *
393 * This function is only called from UnserializeV1Stream() and is a wrapper
394 * for SetLegacyIPv6(); however, we keep it for symmetry with
395 * SerializeV1Array() to have pairs of ser/unser functions and to make clear
396 * that if one is altered, a corresponding reverse modification should be
397 * applied to the other.
398 */
399 void UnserializeV1Array(uint8_t (&arr)[V1_SERIALIZATION_SIZE])
400 {
401 // Use SetLegacyIPv6() so that m_net is set correctly. For example
402 // ::FFFF:0102:0304 should be set as m_net=NET_IPV4 (1.2.3.4).
403 SetLegacyIPv6(arr);
404 }
405
406 /**
407 * Unserialize from a pre-ADDRv2/BIP155 format from a stream.
408 */
409 template <typename Stream>
410 void UnserializeV1Stream(Stream& s)
411 {
412 uint8_t serialized[V1_SERIALIZATION_SIZE];
413
414 s >> serialized;
415
416 UnserializeV1Array(serialized);
417 }
418
419 /**
420 * Unserialize from a ADDRv2 / BIP155 format.
421 */
422 template <typename Stream>
423 void UnserializeV2Stream(Stream& s)
424 {
425 uint8_t bip155_net;
426 s >> bip155_net;
427
428 size_t address_size;
429 s >> COMPACTSIZE(address_size);
430
431 if (address_size > MAX_ADDRV2_SIZE) {
432 throw std::ios_base::failure(strprintf(
433 "Address too long: %u > %u", address_size, MAX_ADDRV2_SIZE));
434 }
435
436 m_scope_id = 0;
437
438 if (SetNetFromBIP155Network(bip155_net, address_size)) {
439 m_addr.resize(address_size);
440 s >> Span{m_addr};
441
442 if (m_net != NET_IPV6) {
443 return;
444 }
445
446 // Do some special checks on IPv6 addresses.
447
448 // Recognize NET_INTERNAL embedded in IPv6, such addresses are not
449 // gossiped but could be coming from addrman, when unserializing from
450 // disk.
451 if (util::HasPrefix(m_addr, INTERNAL_IN_IPV6_PREFIX)) {
452 m_net = NET_INTERNAL;
453 memmove(m_addr.data(), m_addr.data() + INTERNAL_IN_IPV6_PREFIX.size(),
454 ADDR_INTERNAL_SIZE);
455 m_addr.resize(ADDR_INTERNAL_SIZE);
456 return;
457 }
458
459 if (!util::HasPrefix(m_addr, IPV4_IN_IPV6_PREFIX) &&
460 !util::HasPrefix(m_addr, TORV2_IN_IPV6_PREFIX)) {
461 return;
462 }
463
464 // IPv4 and TORv2 are not supposed to be embedded in IPv6 (like in V1
465 // encoding). Unserialize as !IsValid(), thus ignoring them.
466 } else {
467 // If we receive an unknown BIP155 network id (from the future?) then
468 // ignore the address - unserialize as !IsValid().
469 s.ignore(address_size);
470 }
471
472 // Mimic a default-constructed CNetAddr object which is !IsValid() and thus
473 // will not be gossiped, but continue reading next addresses from the stream.
474 m_net = NET_IPV6;
475 m_addr.assign(ADDR_IPV6_SIZE, 0x0);
476 }
477 };
478
479 class CSubNet
480 {
481 protected:
482 /// Network (base) address
483 CNetAddr network;
484 /// Netmask, in network byte order
485 uint8_t netmask[16];
486 /// Is this value valid? (only used to signal parse errors)
487 bool valid;
488
489 public:
490 /**
491 * Construct an invalid subnet (empty, `Match()` always returns false).
492 */
493 CSubNet();
494
495 /**
496 * Construct from a given network start and number of bits (CIDR mask).
497 * @param[in] addr Network start. Must be IPv4 or IPv6, otherwise an invalid subnet is
498 * created.
499 * @param[in] mask CIDR mask, must be in [0, 32] for IPv4 addresses and in [0, 128] for
500 * IPv6 addresses. Otherwise an invalid subnet is created.
501 */
502 CSubNet(const CNetAddr& addr, uint8_t mask);
503
504 /**
505 * Construct from a given network start and mask.
506 * @param[in] addr Network start. Must be IPv4 or IPv6, otherwise an invalid subnet is
507 * created.
508 * @param[in] mask Network mask, must be of the same type as `addr` and not contain 0-bits
509 * followed by 1-bits. Otherwise an invalid subnet is created.
510 */
511 CSubNet(const CNetAddr& addr, const CNetAddr& mask);
512
513 /**
514 * Construct a single-host subnet.
515 * @param[in] addr The sole address to be contained in the subnet, can also be non-IPv[46].
516 */
517 explicit CSubNet(const CNetAddr& addr);
518
519 bool Match(const CNetAddr& addr) const;
520
521 std::string ToString() const;
522 bool IsValid() const;
523
524 friend bool operator==(const CSubNet& a, const CSubNet& b);
525 friend bool operator!=(const CSubNet& a, const CSubNet& b) { return !(a == b); }
526 friend bool operator<(const CSubNet& a, const CSubNet& b);
527 };
528
529 /** A combination of a network address (CNetAddr) and a (TCP) port */
530 class CService : public CNetAddr
531 {
532 protected:
533 uint16_t port; // host order
534
535 public:
536 CService();
537 CService(const CNetAddr& ip, uint16_t port);
538 CService(const struct in_addr& ipv4Addr, uint16_t port);
539 explicit CService(const struct sockaddr_in& addr);
540 uint16_t GetPort() const;
541 bool GetSockAddr(struct sockaddr* paddr, socklen_t* addrlen) const;
542 /**
543 * Set CService from a network sockaddr.
544 * @param[in] paddr Pointer to sockaddr structure
545 * @param[in] addrlen Length of sockaddr structure in bytes. This will be checked to exactly match the length of
546 * a socket address of the provided family, unless std::nullopt is passed
547 * @returns true on success
548 */
549 bool SetSockAddr(const struct sockaddr* paddr, socklen_t addrlen);
550 /**
551 * Get the address family
552 * @returns AF_UNSPEC if unspecified
553 */
554 [[nodiscard]] sa_family_t GetSAFamily() const;
555 friend bool operator==(const CService& a, const CService& b);
556 friend bool operator!=(const CService& a, const CService& b) { return !(a == b); }
557 friend bool operator<(const CService& a, const CService& b);
558 std::vector<unsigned char> GetKey() const;
559 std::string ToStringAddrPort() const;
560
561 CService(const struct in6_addr& ipv6Addr, uint16_t port);
562 explicit CService(const struct sockaddr_in6& addr);
563
564 SERIALIZE_METHODS(CService, obj)
565 {
566 READWRITE(AsBase<CNetAddr>(obj), Using<BigEndianFormatter<2>>(obj.port));
567 }
568
569 friend class CServiceHash;
570 friend CService MaybeFlipIPv6toCJDNS(const CService& service);
571 };
572
573 class CServiceHash
574 {
575 public:
576 CServiceHash()
577 : m_salt_k0{FastRandomContext().rand64()},
578 m_salt_k1{FastRandomContext().rand64()}
579 {
580 }
581
582 CServiceHash(uint64_t salt_k0, uint64_t salt_k1) : m_salt_k0{salt_k0}, m_salt_k1{salt_k1} {}
583
584 size_t operator()(const CService& a) const noexcept
585 {
586 CSipHasher hasher(m_salt_k0, m_salt_k1);
587 hasher.Write(a.m_net);
588 hasher.Write(a.port);
589 hasher.Write(a.m_addr);
590 return static_cast<size_t>(hasher.Finalize());
591 }
592
593 private:
594 const uint64_t m_salt_k0;
595 const uint64_t m_salt_k1;
596 };
597
598 #endif // LIMENKA_NETADDRESS_H
599