Branch data Line data Source code
1 : : // Copyright (c) 2024-present The Bitcoin Core developers
2 : : // Distributed under the MIT software license, see the accompanying
3 : : // file COPYING or https://www.opensource.org/licenses/mit-license.php.
4 : :
5 : : #include <common/pcp.h>
6 : :
7 : : #include <common/netif.h>
8 : : #include <crypto/common.h>
9 : : #include <logging.h>
10 : : #include <netaddress.h>
11 : : #include <netbase.h>
12 : : #include <random.h>
13 : : #include <span.h>
14 : : #include <util/check.h>
15 : : #include <util/readwritefile.h>
16 : : #include <util/sock.h>
17 : : #include <util/strencodings.h>
18 : : #include <util/threadinterrupt.h>
19 : :
20 : : namespace {
21 : :
22 : : // RFC6886 NAT-PMP and RFC6887 Port Control Protocol (PCP) implementation.
23 : : // NAT-PMP and PCP use network byte order (big-endian).
24 : :
25 : : // NAT-PMP (v0) protocol constants.
26 : : //! NAT-PMP uses a fixed server port number (RFC6887 section 1.1).
27 : : constexpr uint16_t NATPMP_SERVER_PORT = 5351;
28 : : //! Version byte for NATPMP (RFC6886 1.1)
29 : : constexpr uint8_t NATPMP_VERSION = 0;
30 : : //! Request opcode base (RFC6886 3).
31 : : constexpr uint8_t NATPMP_REQUEST = 0x00;
32 : : //! Response opcode base (RFC6886 3).
33 : : constexpr uint8_t NATPMP_RESPONSE = 0x80;
34 : : //! Get external address (RFC6886 3.2)
35 : : constexpr uint8_t NATPMP_OP_GETEXTERNAL = 0x00;
36 : : //! Map TCP port (RFC6886 3.3)
37 : : constexpr uint8_t NATPMP_OP_MAP_TCP = 0x02;
38 : : //! Shared request header size in bytes.
39 : : constexpr size_t NATPMP_REQUEST_HDR_SIZE = 2;
40 : : //! Shared response header (minimum) size in bytes.
41 : : constexpr size_t NATPMP_RESPONSE_HDR_SIZE = 8;
42 : : //! GETEXTERNAL request size in bytes, including header (RFC6886 3.2).
43 : : constexpr size_t NATPMP_GETEXTERNAL_REQUEST_SIZE = NATPMP_REQUEST_HDR_SIZE + 0;
44 : : //! GETEXTERNAL response size in bytes, including header (RFC6886 3.2).
45 : : constexpr size_t NATPMP_GETEXTERNAL_RESPONSE_SIZE = NATPMP_RESPONSE_HDR_SIZE + 4;
46 : : //! MAP request size in bytes, including header (RFC6886 3.3).
47 : : constexpr size_t NATPMP_MAP_REQUEST_SIZE = NATPMP_REQUEST_HDR_SIZE + 10;
48 : : //! MAP response size in bytes, including header (RFC6886 3.3).
49 : : constexpr size_t NATPMP_MAP_RESPONSE_SIZE = NATPMP_RESPONSE_HDR_SIZE + 8;
50 : :
51 : : // Shared header offsets (RFC6886 3.2, 3.3), relative to start of packet.
52 : : //! Offset of version field in packets.
53 : : constexpr size_t NATPMP_HDR_VERSION_OFS = 0;
54 : : //! Offset of opcode field in packets
55 : : constexpr size_t NATPMP_HDR_OP_OFS = 1;
56 : : //! Offset of result code in packets. Result codes are 16 bit in NAT-PMP instead of 8 bit in PCP.
57 : : constexpr size_t NATPMP_RESPONSE_HDR_RESULT_OFS = 2;
58 : :
59 : : // GETEXTERNAL response offsets (RFC6886 3.2), relative to start of packet.
60 : : //! Returned external address
61 : : constexpr size_t NATPMP_GETEXTERNAL_RESPONSE_IP_OFS = 8;
62 : :
63 : : // MAP request offsets (RFC6886 3.3), relative to start of packet.
64 : : //! Internal port to be mapped.
65 : : constexpr size_t NATPMP_MAP_REQUEST_INTERNAL_PORT_OFS = 4;
66 : : //! Suggested external port for mapping.
67 : : constexpr size_t NATPMP_MAP_REQUEST_EXTERNAL_PORT_OFS = 6;
68 : : //! Requested port mapping lifetime in seconds.
69 : : constexpr size_t NATPMP_MAP_REQUEST_LIFETIME_OFS = 8;
70 : :
71 : : // MAP response offsets (RFC6886 3.3), relative to start of packet.
72 : : //! Internal port for mapping (will match internal port of request).
73 : : constexpr size_t NATPMP_MAP_RESPONSE_INTERNAL_PORT_OFS = 8;
74 : : //! External port for mapping.
75 : : constexpr size_t NATPMP_MAP_RESPONSE_EXTERNAL_PORT_OFS = 10;
76 : : //! Created port mapping lifetime in seconds.
77 : : constexpr size_t NATPMP_MAP_RESPONSE_LIFETIME_OFS = 12;
78 : :
79 : : // Relevant NETPMP result codes (RFC6886 3.5).
80 : : //! Result code representing success status.
81 : : constexpr uint8_t NATPMP_RESULT_SUCCESS = 0;
82 : : //! Result code representing unsupported version.
83 : : constexpr uint8_t NATPMP_RESULT_UNSUPP_VERSION = 1;
84 : : //! Result code representing lack of resources.
85 : : constexpr uint8_t NATPMP_RESULT_NO_RESOURCES = 4;
86 : :
87 : : //! Mapping of NATPMP result code to string (RFC6886 3.5). Result codes <=2 match PCP.
88 : : const std::map<uint16_t, std::string> NATPMP_RESULT_STR{
89 : : {0, "SUCCESS"},
90 : : {1, "UNSUPP_VERSION"},
91 : : {2, "NOT_AUTHORIZED"},
92 : : {3, "NETWORK_FAILURE"},
93 : : {4, "NO_RESOURCES"},
94 : : {5, "UNSUPP_OPCODE"},
95 : : };
96 : :
97 : : // PCP (v2) protocol constants.
98 : : //! Maximum packet size in bytes (RFC6887 section 7).
99 : : constexpr size_t PCP_MAX_SIZE = 1100;
100 : : //! PCP uses a fixed server port number (RFC6887 section 19.1). Shared with NAT-PMP.
101 : : constexpr uint16_t PCP_SERVER_PORT = NATPMP_SERVER_PORT;
102 : : //! Version byte. 0 is NAT-PMP (RFC6886), 1 is forbidden, 2 for PCP (RFC6887).
103 : : constexpr uint8_t PCP_VERSION = 2;
104 : : //! PCP Request Header. See RFC6887 section 7.1. Shared with NAT-PMP.
105 : : constexpr uint8_t PCP_REQUEST = NATPMP_REQUEST; // R = 0
106 : : //! PCP Response Header. See RFC6887 section 7.2. Shared with NAT-PMP.
107 : : constexpr uint8_t PCP_RESPONSE = NATPMP_RESPONSE; // R = 1
108 : : //! Map opcode. See RFC6887 section 19.2
109 : : constexpr uint8_t PCP_OP_MAP = 0x01;
110 : : //! TCP protocol number (IANA).
111 : : constexpr uint16_t PCP_PROTOCOL_TCP = 6;
112 : : //! Request and response header size in bytes (RFC6887 section 7.1).
113 : : constexpr size_t PCP_HDR_SIZE = 24;
114 : : //! Map request and response size in bytes (RFC6887 section 11.1).
115 : : constexpr size_t PCP_MAP_SIZE = 36;
116 : :
117 : : // Header offsets shared between request and responses (RFC6887 7.1, 7.2), relative to start of packet.
118 : : //! Version field (1 byte).
119 : : constexpr size_t PCP_HDR_VERSION_OFS = NATPMP_HDR_VERSION_OFS;
120 : : //! Opcode field (1 byte).
121 : : constexpr size_t PCP_HDR_OP_OFS = NATPMP_HDR_OP_OFS;
122 : : //! Requested lifetime (request), granted lifetime (response) (4 bytes).
123 : : constexpr size_t PCP_HDR_LIFETIME_OFS = 4;
124 : :
125 : : // Request header offsets (RFC6887 7.1), relative to start of packet.
126 : : //! PCP client's IP address (16 bytes).
127 : : constexpr size_t PCP_REQUEST_HDR_IP_OFS = 8;
128 : :
129 : : // Response header offsets (RFC6887 7.2), relative to start of packet.
130 : : //! Result code (1 byte).
131 : : constexpr size_t PCP_RESPONSE_HDR_RESULT_OFS = 3;
132 : :
133 : : // MAP request/response offsets (RFC6887 11.1), relative to start of opcode-specific data.
134 : : //! Mapping nonce (12 bytes).
135 : : constexpr size_t PCP_MAP_NONCE_OFS = 0;
136 : : //! Protocol (1 byte).
137 : : constexpr size_t PCP_MAP_PROTOCOL_OFS = 12;
138 : : //! Internal port for mapping (2 bytes).
139 : : constexpr size_t PCP_MAP_INTERNAL_PORT_OFS = 16;
140 : : //! Suggested external port (request), assigned external port (response) (2 bytes).
141 : : constexpr size_t PCP_MAP_EXTERNAL_PORT_OFS = 18;
142 : : //! Suggested external IP (request), assigned external IP (response) (16 bytes).
143 : : constexpr size_t PCP_MAP_EXTERNAL_IP_OFS = 20;
144 : :
145 : : //! Result code representing success (RFC6887 7.4), shared with NAT-PMP.
146 : : constexpr uint8_t PCP_RESULT_SUCCESS = NATPMP_RESULT_SUCCESS;
147 : : //! Result code representing lack of resources (RFC6887 7.4).
148 : : constexpr uint8_t PCP_RESULT_NO_RESOURCES = 8;
149 : :
150 : : //! Mapping of PCP result code to string (RFC6887 7.4). Result codes <=2 match NAT-PMP.
151 : : const std::map<uint8_t, std::string> PCP_RESULT_STR{
152 : : {0, "SUCCESS"},
153 : : {1, "UNSUPP_VERSION"},
154 : : {2, "NOT_AUTHORIZED"},
155 : : {3, "MALFORMED_REQUEST"},
156 : : {4, "UNSUPP_OPCODE"},
157 : : {5, "UNSUPP_OPTION"},
158 : : {6, "MALFORMED_OPTION"},
159 : : {7, "NETWORK_FAILURE"},
160 : : {8, "NO_RESOURCES"},
161 : : {9, "UNSUPP_PROTOCOL"},
162 : : {10, "USER_EX_QUOTA"},
163 : : {11, "CANNOT_PROVIDE_EXTERNAL"},
164 : : {12, "ADDRESS_MISMATCH"},
165 : : {13, "EXCESSIVE_REMOTE_PEER"},
166 : : };
167 : :
168 : : //! Return human-readable string from NATPMP result code.
169 : 5 : std::string NATPMPResultString(uint16_t result_code)
170 : : {
171 : 5 : auto result_i = NATPMP_RESULT_STR.find(result_code);
172 [ + + - + : 14 : return strprintf("%s (code %d)", result_i == NATPMP_RESULT_STR.end() ? "(unknown)" : result_i->second, result_code);
+ - ]
173 : : }
174 : :
175 : : //! Return human-readable string from PCP result code.
176 : 7 : std::string PCPResultString(uint8_t result_code)
177 : : {
178 : 7 : auto result_i = PCP_RESULT_STR.find(result_code);
179 [ + + - + : 20 : return strprintf("%s (code %d)", result_i == PCP_RESULT_STR.end() ? "(unknown)" : result_i->second, result_code);
+ - ]
180 : : }
181 : :
182 : : //! Wrap address in IPv6 according to RFC6887. wrapped_addr needs to be able to store 16 bytes.
183 : 159 : [[nodiscard]] bool PCPWrapAddress(std::span<uint8_t> wrapped_addr, const CNetAddr &addr)
184 : : {
185 : 159 : Assume(wrapped_addr.size() == ADDR_IPV6_SIZE);
186 [ + + ]: 159 : if (addr.IsIPv4()) {
187 : 126 : struct in_addr addr4;
188 [ + - ]: 126 : if (!addr.GetInAddr(&addr4)) return false;
189 : : // Section 5: "When the address field holds an IPv4 address, an IPv4-mapped IPv6 address [RFC4291] is used (::ffff:0:0/96)."
190 : 126 : std::memcpy(wrapped_addr.data(), IPV4_IN_IPV6_PREFIX.data(), IPV4_IN_IPV6_PREFIX.size());
191 : 126 : std::memcpy(wrapped_addr.data() + IPV4_IN_IPV6_PREFIX.size(), &addr4, ADDR_IPV4_SIZE);
192 : 126 : return true;
193 [ + + ]: 33 : } else if (addr.IsIPv6()) {
194 : 31 : struct in6_addr addr6;
195 [ + - ]: 31 : if (!addr.GetIn6Addr(&addr6)) return false;
196 : 31 : std::memcpy(wrapped_addr.data(), &addr6, ADDR_IPV6_SIZE);
197 : 31 : return true;
198 : : } else {
199 : : return false;
200 : : }
201 : : }
202 : :
203 : : //! Unwrap PCP-encoded address according to RFC6887.
204 : 33 : CNetAddr PCPUnwrapAddress(std::span<const uint8_t> wrapped_addr)
205 : : {
206 : 33 : Assume(wrapped_addr.size() == ADDR_IPV6_SIZE);
207 [ + + ]: 33 : if (util::HasPrefix(wrapped_addr, IPV4_IN_IPV6_PREFIX)) {
208 : 4 : struct in_addr addr4;
209 : 4 : std::memcpy(&addr4, wrapped_addr.data() + IPV4_IN_IPV6_PREFIX.size(), ADDR_IPV4_SIZE);
210 : 4 : return CNetAddr(addr4);
211 : : } else {
212 : 29 : struct in6_addr addr6;
213 : 29 : std::memcpy(&addr6, wrapped_addr.data(), ADDR_IPV6_SIZE);
214 : 29 : return CNetAddr(addr6);
215 : : }
216 : : }
217 : :
218 : : //! PCP or NAT-PMP send-receive loop.
219 : 158 : std::optional<std::vector<uint8_t>> PCPSendRecv(Sock &sock, const std::string &protocol, std::span<const uint8_t> request, int num_tries,
220 : : std::chrono::milliseconds timeout_per_try,
221 : : std::function<bool(std::span<const uint8_t>)> check_packet,
222 : : CThreadInterrupt& interrupt)
223 : : {
224 : 158 : using namespace std::chrono;
225 : : // UDP is a potentially lossy protocol, so we try to send again a few times.
226 : 158 : uint8_t response[PCP_MAX_SIZE];
227 : 158 : bool got_response = false;
228 : 158 : int recvsz = 0;
229 [ + + + + ]: 551 : for (int ntry = 0; !got_response && ntry < num_tries; ++ntry) {
230 [ + + ]: 466 : if (ntry > 0) {
231 [ - + ]: 308 : LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "%s: Retrying (%d)\n", protocol, ntry);
232 : : }
233 : : // Dispatch packet to gateway.
234 [ + + ]: 466 : if (sock.Send(request.data(), request.size(), 0) != static_cast<ssize_t>(request.size())) {
235 [ - + - - ]: 62 : LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "%s: Could not send request: %s\n", protocol, NetworkErrorString(WSAGetLastError()));
236 : 62 : return std::nullopt; // Network-level error, probably no use retrying.
237 : : }
238 : :
239 : : // Wait for response(s) until we get a valid response, a network error, or time out.
240 : 404 : auto cur_time = time_point_cast<milliseconds>(MockableSteadyClock::now());
241 : 404 : auto deadline = cur_time + timeout_per_try;
242 [ + + ]: 683 : while ((cur_time = time_point_cast<milliseconds>(MockableSteadyClock::now())) < deadline) {
243 [ - + ]: 404 : if (interrupt) return std::nullopt;
244 : 404 : Sock::Event occurred = 0;
245 [ + + ]: 404 : if (!sock.Wait(deadline - cur_time, Sock::RECV, &occurred)) {
246 [ + - + - ]: 10 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "%s: Could not wait on socket: %s\n", protocol, NetworkErrorString(WSAGetLastError()));
247 : 5 : return std::nullopt; // Network-level error, probably no use retrying.
248 : : }
249 [ + + ]: 399 : if (!occurred) {
250 [ - + ]: 42 : LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "%s: Timeout\n", protocol);
251 : : break; // Retry.
252 : : }
253 : :
254 : : // Receive response.
255 : 357 : recvsz = sock.Recv(response, sizeof(response), MSG_DONTWAIT);
256 [ + + ]: 357 : if (recvsz < 0) {
257 [ - + - - ]: 6 : LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "%s: Could not receive response: %s\n", protocol, NetworkErrorString(WSAGetLastError()));
258 : 6 : return std::nullopt; // Network-level error, probably no use retrying.
259 : : }
260 [ - + - - ]: 351 : LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "%s: Received response of %d bytes: %s\n", protocol, recvsz, HexStr(std::span(response, recvsz)));
261 : :
262 [ + + ]: 351 : if (check_packet(std::span<uint8_t>(response, recvsz))) {
263 : : got_response = true; // Got expected response, break from receive loop as well as from retry loop.
264 : : break;
265 : : }
266 : : }
267 : : }
268 [ + + ]: 85 : if (!got_response) {
269 [ - + ]: 13 : LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "%s: Giving up after %d tries\n", protocol, num_tries);
270 : 13 : return std::nullopt;
271 : : }
272 : 72 : return std::vector<uint8_t>(response, response + recvsz);
273 : : }
274 : :
275 : : }
276 : :
277 : 110 : std::variant<MappingResult, MappingError> NATPMPRequestPortMap(const CNetAddr &gateway, uint16_t port, uint32_t lifetime, CThreadInterrupt& interrupt, int num_tries, std::chrono::milliseconds timeout_per_try)
278 : : {
279 : 110 : struct sockaddr_storage dest_addr;
280 : 110 : socklen_t dest_addrlen = sizeof(struct sockaddr_storage);
281 : :
282 [ - + - - ]: 110 : LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "natpmp: Requesting port mapping port %d from gateway %s\n", port, gateway.ToStringAddr());
283 : :
284 : : // Validate gateway, make sure it's IPv4. NAT-PMP does not support IPv6.
285 [ + - + + ]: 110 : if (!CService(gateway, PCP_SERVER_PORT).GetSockAddr((struct sockaddr*)&dest_addr, &dest_addrlen)) return MappingError::NETWORK_ERROR;
286 [ + + ]: 95 : if (dest_addr.ss_family != AF_INET) return MappingError::NETWORK_ERROR;
287 : :
288 : : // Create IPv4 UDP socket
289 : 70 : auto sock{CreateSock(AF_INET, SOCK_DGRAM, IPPROTO_UDP)};
290 [ - + ]: 70 : if (!sock) {
291 [ # # # # : 0 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "natpmp: Could not create UDP socket: %s\n", NetworkErrorString(WSAGetLastError()));
# # # # ]
292 : 0 : return MappingError::NETWORK_ERROR;
293 : : }
294 : :
295 : : // Associate UDP socket to gateway.
296 [ + - + + ]: 70 : if (sock->Connect((struct sockaddr*)&dest_addr, dest_addrlen) != 0) {
297 [ + - + - : 4 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "natpmp: Could not connect to gateway: %s\n", NetworkErrorString(WSAGetLastError()));
+ - + - ]
298 : 2 : return MappingError::NETWORK_ERROR;
299 : : }
300 : :
301 : : // Use getsockname to get the address toward the default gateway (the internal address).
302 : 68 : struct sockaddr_in internal;
303 : 68 : socklen_t internal_addrlen = sizeof(struct sockaddr_in);
304 [ + - + + ]: 68 : if (sock->GetSockName((struct sockaddr*)&internal, &internal_addrlen) != 0) {
305 [ + - + - : 28 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "natpmp: Could not get sock name: %s\n", NetworkErrorString(WSAGetLastError()));
+ - + - ]
306 : 14 : return MappingError::NETWORK_ERROR;
307 : : }
308 : :
309 : : // Request external IP address (RFC6886 section 3.2).
310 [ + - ]: 54 : std::vector<uint8_t> request(NATPMP_GETEXTERNAL_REQUEST_SIZE);
311 [ - + ]: 54 : request[NATPMP_HDR_VERSION_OFS] = NATPMP_VERSION;
312 : 54 : request[NATPMP_HDR_OP_OFS] = NATPMP_REQUEST | NATPMP_OP_GETEXTERNAL;
313 : :
314 [ - + + - ]: 108 : auto recv_res = PCPSendRecv(*sock, "natpmp", request, num_tries, timeout_per_try,
315 [ - + ]: 54 : [&](const std::span<const uint8_t> response) -> bool {
316 [ + + ]: 116 : if (response.size() < NATPMP_GETEXTERNAL_RESPONSE_SIZE) {
317 [ + - ]: 51 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "natpmp: Response too small\n");
318 : 51 : return false; // Wasn't response to what we expected, try receiving next packet.
319 : : }
320 [ + + + + ]: 65 : if (response[NATPMP_HDR_VERSION_OFS] != NATPMP_VERSION || response[NATPMP_HDR_OP_OFS] != (NATPMP_RESPONSE | NATPMP_OP_GETEXTERNAL)) {
321 [ + - ]: 36 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "natpmp: Response to wrong command\n");
322 : 36 : return false; // Wasn't response to what we expected, try receiving next packet.
323 : : }
324 : : return true;
325 : : },
326 [ + - ]: 54 : interrupt);
327 : :
328 : 54 : struct in_addr external_addr;
329 [ + + ]: 54 : if (recv_res) {
330 [ - + ]: 29 : const std::span<const uint8_t> response = *recv_res;
331 : :
332 [ + - ]: 29 : Assume(response.size() >= NATPMP_GETEXTERNAL_RESPONSE_SIZE);
333 [ + + ]: 29 : uint16_t result_code = ReadBE16(response.data() + NATPMP_RESPONSE_HDR_RESULT_OFS);
334 [ + + ]: 29 : if (result_code != NATPMP_RESULT_SUCCESS) {
335 [ + - + - : 6 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "natpmp: Getting external address failed with result %s\n", NATPMPResultString(result_code));
+ - + - ]
336 : 3 : return MappingError::PROTOCOL_ERROR;
337 : : }
338 : :
339 [ + - ]: 26 : std::memcpy(&external_addr, response.data() + NATPMP_GETEXTERNAL_RESPONSE_IP_OFS, ADDR_IPV4_SIZE);
340 : : } else {
341 : 25 : return MappingError::NETWORK_ERROR;
342 : : }
343 : :
344 : : // Create TCP mapping request (RFC6886 section 3.3).
345 [ + - ]: 52 : request = std::vector<uint8_t>(NATPMP_MAP_REQUEST_SIZE);
346 : 26 : request[NATPMP_HDR_VERSION_OFS] = NATPMP_VERSION;
347 : 26 : request[NATPMP_HDR_OP_OFS] = NATPMP_REQUEST | NATPMP_OP_MAP_TCP;
348 : 26 : WriteBE16(request.data() + NATPMP_MAP_REQUEST_INTERNAL_PORT_OFS, port);
349 : 26 : WriteBE16(request.data() + NATPMP_MAP_REQUEST_EXTERNAL_PORT_OFS, port);
350 : 26 : WriteBE32(request.data() + NATPMP_MAP_REQUEST_LIFETIME_OFS, lifetime);
351 : :
352 [ + - + - ]: 52 : recv_res = PCPSendRecv(*sock, "natpmp", request, num_tries, timeout_per_try,
353 [ - + ]: 26 : [&](const std::span<const uint8_t> response) -> bool {
354 [ + + ]: 74 : if (response.size() < NATPMP_MAP_RESPONSE_SIZE) {
355 [ + - ]: 21 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "natpmp: Response too small\n");
356 : 21 : return false; // Wasn't response to what we expected, try receiving next packet.
357 : : }
358 [ + + + + ]: 53 : if (response[0] != NATPMP_VERSION || response[1] != (NATPMP_RESPONSE | NATPMP_OP_MAP_TCP)) {
359 [ + - ]: 31 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "natpmp: Response to wrong command\n");
360 : 31 : return false; // Wasn't response to what we expected, try receiving next packet.
361 : : }
362 [ + + ]: 22 : uint16_t internal_port = ReadBE16(response.data() + NATPMP_MAP_RESPONSE_INTERNAL_PORT_OFS);
363 [ + + ]: 22 : if (internal_port != port) {
364 [ + - ]: 13 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "natpmp: Response port doesn't match request\n");
365 : 13 : return false; // Wasn't response to what we expected, try receiving next packet.
366 : : }
367 : : return true;
368 : : },
369 : 26 : interrupt);
370 : :
371 [ + + ]: 26 : if (recv_res) {
372 [ - + ]: 9 : const std::span<uint8_t> response = *recv_res;
373 : :
374 [ + - ]: 9 : Assume(response.size() >= NATPMP_MAP_RESPONSE_SIZE);
375 [ + + ]: 9 : uint16_t result_code = ReadBE16(response.data() + NATPMP_RESPONSE_HDR_RESULT_OFS);
376 [ + + ]: 9 : if (result_code != NATPMP_RESULT_SUCCESS) {
377 [ + - + - : 4 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "natpmp: Port mapping failed with result %s\n", NATPMPResultString(result_code));
+ - + - ]
378 [ + + ]: 2 : if (result_code == NATPMP_RESULT_NO_RESOURCES) {
379 : 1 : return MappingError::NO_RESOURCES;
380 : : }
381 : 1 : return MappingError::PROTOCOL_ERROR;
382 : : }
383 : :
384 [ + - ]: 7 : uint32_t lifetime_ret = ReadBE32(response.data() + NATPMP_MAP_RESPONSE_LIFETIME_OFS);
385 [ + - ]: 7 : uint16_t external_port = ReadBE16(response.data() + NATPMP_MAP_RESPONSE_EXTERNAL_PORT_OFS);
386 [ + - + - ]: 14 : return MappingResult(NATPMP_VERSION, CService(internal.sin_addr, port), CService(external_addr, external_port), lifetime_ret);
387 : : } else {
388 : 17 : return MappingError::NETWORK_ERROR;
389 : : }
390 : 70 : }
391 : :
392 : 153 : std::variant<MappingResult, MappingError> PCPRequestPortMap(const PCPMappingNonce &nonce, const CNetAddr &gateway, const CNetAddr &bind, uint16_t port, uint32_t lifetime, CThreadInterrupt& interrupt, int num_tries, std::chrono::milliseconds timeout_per_try)
393 : : {
394 : 153 : struct sockaddr_storage dest_addr, bind_addr;
395 : 153 : socklen_t dest_addrlen = sizeof(struct sockaddr_storage), bind_addrlen = sizeof(struct sockaddr_storage);
396 : :
397 [ - + - - : 153 : LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "pcp: Requesting port mapping for addr %s port %d from gateway %s\n", bind.ToStringAddr(), port, gateway.ToStringAddr());
- - ]
398 : :
399 : : // Validate addresses, make sure they're the same network family.
400 [ + - + + ]: 153 : if (!CService(gateway, PCP_SERVER_PORT).GetSockAddr((struct sockaddr*)&dest_addr, &dest_addrlen)) return MappingError::NETWORK_ERROR;
401 [ + - + + ]: 136 : if (!CService(bind, 0).GetSockAddr((struct sockaddr*)&bind_addr, &bind_addrlen)) return MappingError::NETWORK_ERROR;
402 [ + + ]: 131 : if (dest_addr.ss_family != bind_addr.ss_family) return MappingError::NETWORK_ERROR;
403 : :
404 : : // Create UDP socket (IPv4 or IPv6 based on provided gateway).
405 : 121 : auto sock{CreateSock(dest_addr.ss_family, SOCK_DGRAM, IPPROTO_UDP)};
406 [ - + ]: 121 : if (!sock) {
407 [ # # # # : 0 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "pcp: Could not create UDP socket: %s\n", NetworkErrorString(WSAGetLastError()));
# # # # ]
408 : 0 : return MappingError::NETWORK_ERROR;
409 : : }
410 : :
411 : : // Make sure that we send from requested destination address, anything else will be
412 : : // rejected by a security-conscious router.
413 [ + - + + ]: 121 : if (sock->Bind((struct sockaddr*)&bind_addr, bind_addrlen) != 0) {
414 [ + - + - : 6 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "pcp: Could not bind to address: %s\n", NetworkErrorString(WSAGetLastError()));
+ - + - ]
415 : 3 : return MappingError::NETWORK_ERROR;
416 : : }
417 : :
418 : : // Associate UDP socket to gateway.
419 [ + - + + ]: 118 : if (sock->Connect((struct sockaddr*)&dest_addr, dest_addrlen) != 0) {
420 [ + - + - : 4 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "pcp: Could not connect to gateway: %s\n", NetworkErrorString(WSAGetLastError()));
+ - + - ]
421 : 2 : return MappingError::NETWORK_ERROR;
422 : : }
423 : :
424 : : // Use getsockname to get the address toward the default gateway (the internal address),
425 : : // in case we don't know what address to map
426 : : // (this is only needed if bind is INADDR_ANY, but it doesn't hurt as an extra check).
427 : 116 : struct sockaddr_storage internal_addr;
428 : 116 : socklen_t internal_addrlen = sizeof(struct sockaddr_storage);
429 [ + - + + ]: 116 : if (sock->GetSockName((struct sockaddr*)&internal_addr, &internal_addrlen) != 0) {
430 [ + - + - : 64 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "pcp: Could not get sock name: %s\n", NetworkErrorString(WSAGetLastError()));
+ - + - ]
431 : 32 : return MappingError::NETWORK_ERROR;
432 : : }
433 [ + - ]: 84 : CService internal;
434 [ + - + + ]: 84 : if (!internal.SetSockAddr((struct sockaddr*)&internal_addr, internal_addrlen)) return MappingError::NETWORK_ERROR;
435 [ + - - + : 80 : LogPrintLevel(BCLog::NET, BCLog::Level::Debug, "pcp: Internal address after connect: %s\n", internal.ToStringAddr());
- - - - ]
436 : :
437 : : // Build request packet. Make sure the packet is zeroed so that reserved fields are zero
438 : : // as required by the spec (and not potentially leak data).
439 : : // Make sure there's space for the request header and MAP specific request data.
440 [ + - ]: 80 : std::vector<uint8_t> request(PCP_HDR_SIZE + PCP_MAP_SIZE);
441 : : // Fill in request header, See RFC6887 Figure 2.
442 : 80 : size_t ofs = 0;
443 : 80 : request[ofs + PCP_HDR_VERSION_OFS] = PCP_VERSION;
444 : 80 : request[ofs + PCP_HDR_OP_OFS] = PCP_REQUEST | PCP_OP_MAP;
445 : 80 : WriteBE32(request.data() + ofs + PCP_HDR_LIFETIME_OFS, lifetime);
446 [ - + + - : 80 : if (!PCPWrapAddress(std::span(request).subspan(ofs + PCP_REQUEST_HDR_IP_OFS, ADDR_IPV6_SIZE), internal)) return MappingError::NETWORK_ERROR;
+ + ]
447 : :
448 : 79 : ofs += PCP_HDR_SIZE;
449 : :
450 : : // Fill in MAP request packet, See RFC6887 Figure 9.
451 : : // Randomize mapping nonce (this is repeated in the response, to be able to
452 : : // correlate requests and responses, and used to authenticate changes to the mapping).
453 : 79 : std::memcpy(request.data() + ofs + PCP_MAP_NONCE_OFS, nonce.data(), PCP_MAP_NONCE_SIZE);
454 : 79 : request[ofs + PCP_MAP_PROTOCOL_OFS] = PCP_PROTOCOL_TCP;
455 : 79 : WriteBE16(request.data() + ofs + PCP_MAP_INTERNAL_PORT_OFS, port);
456 : 79 : WriteBE16(request.data() + ofs + PCP_MAP_EXTERNAL_PORT_OFS, port);
457 [ - + + - : 79 : if (!PCPWrapAddress(std::span(request).subspan(ofs + PCP_MAP_EXTERNAL_IP_OFS, ADDR_IPV6_SIZE), bind)) return MappingError::NETWORK_ERROR;
+ + ]
458 : :
459 : 78 : ofs += PCP_MAP_SIZE;
460 [ - + + - ]: 78 : Assume(ofs == request.size());
461 : :
462 : : // Receive loop.
463 : 78 : bool is_natpmp = false;
464 [ + - ]: 156 : auto recv_res = PCPSendRecv(*sock, "pcp", request, num_tries, timeout_per_try,
465 [ + - ]: 78 : [&](const std::span<const uint8_t> response) -> bool {
466 : : // Unsupported version according to RFC6887 appendix A and RFC6886 section 3.5, can fall back to NAT-PMP.
467 [ + + + + : 161 : if (response.size() == NATPMP_RESPONSE_HDR_SIZE && response[PCP_HDR_VERSION_OFS] == NATPMP_VERSION && response[PCP_RESPONSE_HDR_RESULT_OFS] == NATPMP_RESULT_UNSUPP_VERSION) {
+ + ]
468 : 1 : is_natpmp = true;
469 : 1 : return true; // Let it through to caller.
470 : : }
471 [ + + ]: 160 : if (response.size() < (PCP_HDR_SIZE + PCP_MAP_SIZE)) {
472 [ + - ]: 59 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "pcp: Response too small\n");
473 : 59 : return false; // Wasn't response to what we expected, try receiving next packet.
474 : : }
475 [ + + + + ]: 101 : if (response[PCP_HDR_VERSION_OFS] != PCP_VERSION || response[PCP_HDR_OP_OFS] != (PCP_RESPONSE | PCP_OP_MAP)) {
476 [ + - ]: 34 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "pcp: Response to wrong command\n");
477 : 34 : return false; // Wasn't response to what we expected, try receiving next packet.
478 : : }
479 : : // Handle MAP opcode response. See RFC6887 Figure 10.
480 : : // Check that returned mapping nonce matches our request.
481 [ + + ]: 67 : if (!std::ranges::equal(response.subspan(PCP_HDR_SIZE + PCP_MAP_NONCE_OFS, PCP_MAP_NONCE_SIZE), nonce)) {
482 [ + - ]: 10 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "pcp: Mapping nonce mismatch\n");
483 : 10 : return false; // Wasn't response to what we expected, try receiving next packet.
484 : : }
485 : 57 : uint8_t protocol = response[PCP_HDR_SIZE + 12];
486 [ + + ]: 57 : uint16_t internal_port = ReadBE16(response.data() + PCP_HDR_SIZE + 16);
487 [ + + + + ]: 57 : if (protocol != PCP_PROTOCOL_TCP || internal_port != port) {
488 [ + - ]: 24 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "pcp: Response protocol or port doesn't match request\n");
489 : 24 : return false; // Wasn't response to what we expected, try receiving next packet.
490 : : }
491 : : return true;
492 : : },
493 [ + - ]: 78 : interrupt);
494 : :
495 [ + + ]: 78 : if (!recv_res) {
496 : 44 : return MappingError::NETWORK_ERROR;
497 : : }
498 [ + + ]: 34 : if (is_natpmp) {
499 : 1 : return MappingError::UNSUPP_VERSION;
500 : : }
501 : :
502 [ - + ]: 33 : const std::span<const uint8_t> response = *recv_res;
503 : : // If we get here, we got a valid MAP response to our request.
504 : : // Check to see if we got the result we expected.
505 [ + - ]: 33 : Assume(response.size() >= (PCP_HDR_SIZE + PCP_MAP_SIZE));
506 : 33 : uint8_t result_code = response[PCP_RESPONSE_HDR_RESULT_OFS];
507 [ + - ]: 33 : uint32_t lifetime_ret = ReadBE32(response.data() + PCP_HDR_LIFETIME_OFS);
508 [ + - ]: 33 : uint16_t external_port = ReadBE16(response.data() + PCP_HDR_SIZE + PCP_MAP_EXTERNAL_PORT_OFS);
509 [ + - ]: 33 : CNetAddr external_addr{PCPUnwrapAddress(response.subspan(PCP_HDR_SIZE + PCP_MAP_EXTERNAL_IP_OFS, ADDR_IPV6_SIZE))};
510 [ + + ]: 33 : if (result_code != PCP_RESULT_SUCCESS) {
511 [ + - + - : 14 : LogPrintLevel(BCLog::NET, BCLog::Level::Warning, "pcp: Mapping failed with result %s\n", PCPResultString(result_code));
+ - + - ]
512 [ + + ]: 7 : if (result_code == PCP_RESULT_NO_RESOURCES) {
513 : 2 : return MappingError::NO_RESOURCES;
514 : : }
515 : 5 : return MappingError::PROTOCOL_ERROR;
516 : : }
517 : :
518 [ + - + - ]: 52 : return MappingResult(PCP_VERSION, CService(internal, port), CService(external_addr, external_port), lifetime_ret);
519 : 312 : }
520 : :
521 : 33 : std::string MappingResult::ToString() const
522 : : {
523 : 33 : Assume(version == NATPMP_VERSION || version == PCP_VERSION);
524 : 33 : return strprintf("%s:%s -> %s (for %ds)",
525 [ + + ]: 33 : version == NATPMP_VERSION ? "natpmp" : "pcp",
526 [ + - ]: 66 : external.ToStringAddrPort(),
527 : 66 : internal.ToStringAddrPort(),
528 : 33 : lifetime
529 [ + - ]: 66 : );
530 : : }
|
