netaddress.h raw
1 // Copyright (c) 2009-present The Bitcoin Core 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 BITCOIN_NETADDRESS_H
6 #define BITCOIN_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 <string_view>
22 #include <vector>
23
24 /**
25 * A network type.
26 * @note An address may belong to more than one network, for example `10.0.0.1`
27 * belongs to both `NET_UNROUTABLE` and `NET_IPV4`.
28 * Keep these sequential starting from 0 and `NET_MAX` as the last entry.
29 * We have loops like `for (int i = 0; i < NET_MAX; ++i)` that expect to iterate
30 * over all enum values and also `GetExtNetwork()` "extends" this enum by
31 * introducing standalone constants starting from `NET_MAX`.
32 */
33 enum Network {
34 /// Addresses from these networks are not publicly routable on the global Internet.
35 NET_UNROUTABLE = 0,
36
37 /// IPv4
38 NET_IPV4,
39
40 /// IPv6
41 NET_IPV6,
42
43 /// TOR (v2 or v3)
44 NET_ONION,
45
46 /// I2P
47 NET_I2P,
48
49 /// CJDNS
50 NET_CJDNS,
51
52 /// A set of addresses that represent the hash of a string or FQDN. We use
53 /// them in AddrMan to keep track of which DNS seeds were used.
54 NET_INTERNAL,
55
56 /// Dummy value to indicate the number of NET_* constants.
57 NET_MAX,
58 };
59
60 /// Prefix of an IPv6 address when it contains an embedded IPv4 address.
61 /// Used when (un)serializing addresses in ADDRv1 format (pre-BIP155).
62 static const std::array<uint8_t, 12> IPV4_IN_IPV6_PREFIX{
63 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF};
64
65 /// Prefix of an IPv6 address when it contains an embedded TORv2 address.
66 /// Used when (un)serializing addresses in ADDRv1 format (pre-BIP155).
67 /// Such dummy IPv6 addresses are guaranteed to not be publicly routable as they
68 /// fall under RFC4193's fc00::/7 subnet allocated to unique-local addresses.
69 static const std::array<uint8_t, 6> TORV2_IN_IPV6_PREFIX{
70 0xFD, 0x87, 0xD8, 0x7E, 0xEB, 0x43};
71
72 /// Prefix of an IPv6 address when it contains an embedded "internal" address.
73 /// Used when (un)serializing addresses in ADDRv1 format (pre-BIP155).
74 /// The prefix comes from 0xFD + SHA256("bitcoin")[0:5].
75 /// Such dummy IPv6 addresses are guaranteed to not be publicly routable as they
76 /// fall under RFC4193's fc00::/7 subnet allocated to unique-local addresses.
77 static const std::array<uint8_t, 6> INTERNAL_IN_IPV6_PREFIX{
78 0xFD, 0x6B, 0x88, 0xC0, 0x87, 0x24 // 0xFD + sha256("bitcoin")[0:5].
79 };
80
81 /// All CJDNS addresses start with 0xFC. See
82 /// https://github.com/cjdelisle/cjdns/blob/master/doc/Whitepaper.md#pulling-it-all-together
83 static constexpr uint8_t CJDNS_PREFIX{0xFC};
84
85 /// Size of IPv4 address (in bytes).
86 static constexpr size_t ADDR_IPV4_SIZE = 4;
87
88 /// Size of IPv6 address (in bytes).
89 static constexpr size_t ADDR_IPV6_SIZE = 16;
90
91 /// Size of TORv3 address (in bytes). This is the length of just the address
92 /// as used in BIP155, without the checksum and the version byte.
93 static constexpr size_t ADDR_TORV3_SIZE = 32;
94
95 /// Size of I2P address (in bytes).
96 static constexpr size_t ADDR_I2P_SIZE = 32;
97
98 /// Size of CJDNS address (in bytes).
99 static constexpr size_t ADDR_CJDNS_SIZE = 16;
100
101 /// Size of "internal" (NET_INTERNAL) address (in bytes).
102 static constexpr size_t ADDR_INTERNAL_SIZE = 10;
103
104 /// SAM 3.1 and earlier do not support specifying ports and force the port to 0.
105 static constexpr uint16_t I2P_SAM31_PORT{0};
106
107 std::string OnionToString(std::span<const uint8_t> addr);
108
109 /**
110 * Network address.
111 */
112 class CNetAddr
113 {
114 protected:
115 /**
116 * Raw representation of the network address.
117 * In network byte order (big endian) for IPv4 and IPv6.
118 */
119 prevector<ADDR_IPV6_SIZE, uint8_t> m_addr{ADDR_IPV6_SIZE, 0x0};
120
121 /**
122 * Network to which this address belongs.
123 */
124 Network m_net{NET_IPV6};
125
126 /**
127 * Scope id if scoped/link-local IPV6 address.
128 * See https://tools.ietf.org/html/rfc4007
129 */
130 uint32_t m_scope_id{0};
131
132 public:
133 CNetAddr();
134 explicit CNetAddr(const struct in_addr& ipv4Addr);
135 void SetIP(const CNetAddr& ip);
136
137 /**
138 * Set from a legacy IPv6 address.
139 * Legacy IPv6 address may be a normal IPv6 address, or another address
140 * (e.g. IPv4) disguised as IPv6. This encoding is used in the legacy
141 * `addr` encoding.
142 */
143 void SetLegacyIPv6(std::span<const uint8_t> ipv6);
144
145 bool SetInternal(const std::string& name);
146
147 /**
148 * Parse a Tor or I2P address and set this object to it.
149 * @param[in] addr Address to parse, for example
150 * pg6mmjiyjmcrsslvykfwnntlaru7p5svn6y2ymmju6nubxndf4pscryd.onion or
151 * ukeu3k5oycgaauneqgtnvselmt4yemvoilkln7jpvamvfx7dnkdq.b32.i2p.
152 * @returns Whether the operation was successful.
153 * @see CNetAddr::IsTor(), CNetAddr::IsI2P()
154 */
155 bool SetSpecial(std::string_view addr);
156
157 bool IsBindAny() const; // INADDR_ANY equivalent
158 [[nodiscard]] bool IsIPv4() const { return m_net == NET_IPV4; } // IPv4 mapped address (::FFFF:0:0/96, 0.0.0.0/0)
159 [[nodiscard]] bool IsIPv6() const { return m_net == NET_IPV6; } // IPv6 address (not mapped IPv4, not Tor)
160 bool IsRFC1918() const; // IPv4 private networks (10.0.0.0/8, 192.168.0.0/16, 172.16.0.0/12)
161 bool IsRFC2544() const; // IPv4 inter-network communications (198.18.0.0/15)
162 bool IsRFC6598() const; // IPv4 ISP-level NAT (100.64.0.0/10)
163 bool IsRFC5737() const; // IPv4 documentation addresses (192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24)
164 bool IsRFC3849() const; // IPv6 documentation address (2001:0DB8::/32)
165 bool IsRFC3927() const; // IPv4 autoconfig (169.254.0.0/16)
166 bool IsRFC3964() const; // IPv6 6to4 tunnelling (2002::/16)
167 bool IsRFC4193() const; // IPv6 unique local (FC00::/7)
168 bool IsRFC4380() const; // IPv6 Teredo tunnelling (2001::/32)
169 bool IsRFC4843() const; // IPv6 ORCHID (deprecated) (2001:10::/28)
170 bool IsRFC7343() const; // IPv6 ORCHIDv2 (2001:20::/28)
171 bool IsRFC4862() const; // IPv6 autoconfig (FE80::/64)
172 bool IsRFC6052() const; // IPv6 well-known prefix for IPv4-embedded address (64:FF9B::/96)
173 bool IsRFC6145() const; // IPv6 IPv4-translated address (::FFFF:0:0:0/96) (actually defined in RFC2765)
174 bool IsHeNet() const; // IPv6 Hurricane Electric - https://he.net (2001:0470::/36)
175 [[nodiscard]] bool IsTor() const { return m_net == NET_ONION; }
176 [[nodiscard]] bool IsI2P() const { return m_net == NET_I2P; }
177 [[nodiscard]] bool IsCJDNS() const { return m_net == NET_CJDNS; }
178 [[nodiscard]] bool HasCJDNSPrefix() const { return m_addr[0] == CJDNS_PREFIX; }
179 bool IsLocal() const;
180 bool IsRoutable() const;
181 bool IsInternal() const;
182 bool IsValid() const;
183
184 /**
185 * Whether this object is a privacy network.
186 * TODO: consider adding IsCJDNS() here when more peers adopt CJDNS, see:
187 * https://github.com/bitcoin/bitcoin/pull/27411#issuecomment-1497176155
188 */
189 [[nodiscard]] bool IsPrivacyNet() const { return IsTor() || IsI2P(); }
190
191 /**
192 * Check if the current object can be serialized in pre-ADDRv2/BIP155 format.
193 */
194 bool IsAddrV1Compatible() const;
195
196 enum Network GetNetwork() const;
197 std::string ToStringAddr() const;
198 bool GetInAddr(struct in_addr* pipv4Addr) const;
199 Network GetNetClass() const;
200
201 //! For IPv4, mapped IPv4, SIIT translated IPv4, Teredo, 6to4 tunneled addresses, return the relevant IPv4 address as a uint32.
202 uint32_t GetLinkedIPv4() const;
203 //! Whether this address has a linked IPv4 address (see GetLinkedIPv4()).
204 bool HasLinkedIPv4() const;
205
206 std::vector<unsigned char> GetAddrBytes() const;
207 int GetReachabilityFrom(const CNetAddr& paddrPartner) const;
208
209 explicit CNetAddr(const struct in6_addr& pipv6Addr, uint32_t scope = 0);
210 bool GetIn6Addr(struct in6_addr* pipv6Addr) const;
211
212 friend bool operator==(const CNetAddr& a, const CNetAddr& 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(std::string_view 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(std::string_view 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 >> std::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);
526 };
527
528 /** A combination of a network address (CNetAddr) and a (TCP) port */
529 class CService : public CNetAddr
530 {
531 protected:
532 uint16_t port; // host order
533
534 public:
535 CService();
536 CService(const CNetAddr& ip, uint16_t port);
537 CService(const struct in_addr& ipv4Addr, uint16_t port);
538 explicit CService(const struct sockaddr_in& addr);
539 uint16_t GetPort() const;
540 bool GetSockAddr(struct sockaddr* paddr, socklen_t* addrlen) const;
541 /**
542 * Set CService from a network sockaddr.
543 * @param[in] paddr Pointer to sockaddr structure
544 * @param[in] addrlen Length of sockaddr structure in bytes. This will be checked to exactly match the length of
545 * a socket address of the provided family, unless std::nullopt is passed
546 * @returns true on success
547 */
548 bool SetSockAddr(const struct sockaddr* paddr, socklen_t addrlen);
549 /**
550 * Get the address family
551 * @returns AF_UNSPEC if unspecified
552 */
553 [[nodiscard]] sa_family_t GetSAFamily() const;
554 friend bool operator==(const CService& a, const CService& b);
555 friend bool operator<(const CService& a, const CService& b);
556 std::vector<unsigned char> GetKey() const;
557 std::string ToStringAddrPort() const;
558
559 CService(const struct in6_addr& ipv6Addr, uint16_t port);
560 explicit CService(const struct sockaddr_in6& addr);
561
562 SERIALIZE_METHODS(CService, obj)
563 {
564 READWRITE(AsBase<CNetAddr>(obj), Using<BigEndianFormatter<2>>(obj.port));
565 }
566
567 friend class CServiceHash;
568 friend CService MaybeFlipIPv6toCJDNS(const CService& service);
569 };
570
571 class CServiceHash
572 {
573 public:
574 CServiceHash()
575 : m_salt_k0{FastRandomContext().rand64()},
576 m_salt_k1{FastRandomContext().rand64()}
577 {
578 }
579
580 CServiceHash(uint64_t salt_k0, uint64_t salt_k1) : m_salt_k0{salt_k0}, m_salt_k1{salt_k1} {}
581
582 size_t operator()(const CService& a) const noexcept
583 {
584 CSipHasher hasher(m_salt_k0, m_salt_k1);
585 hasher.Write(a.m_net);
586 hasher.Write(a.port);
587 hasher.Write(a.m_addr);
588 return static_cast<size_t>(hasher.Finalize());
589 }
590
591 private:
592 const uint64_t m_salt_k0;
593 const uint64_t m_salt_k1;
594 };
595
596 #endif // BITCOIN_NETADDRESS_H
597