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1 : : // Copyright (c) 2020-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_UTIL_SOCK_H
6 : : #define BITCOIN_UTIL_SOCK_H
7 : :
8 : : #include <compat/compat.h>
9 : : #include <util/time.h>
10 : :
11 : : #include <cstdint>
12 : : #include <limits>
13 : : #include <memory>
14 : : #include <span>
15 : : #include <string>
16 : : #include <unordered_map>
17 : :
18 : : class CThreadInterrupt;
19 : :
20 : : /**
21 : : * Maximum time to wait for I/O readiness.
22 : : * It will take up until this time to break off in case of an interruption.
23 : : */
24 : : static constexpr auto MAX_WAIT_FOR_IO = 1s;
25 : :
26 : : /**
27 : : * RAII helper class that manages a socket and closes it automatically when it goes out of scope.
28 : : */
29 : : class Sock
30 : : {
31 : : public:
32 : : Sock() = delete;
33 : :
34 : : /**
35 : : * Take ownership of an existent socket.
36 : : */
37 : : explicit Sock(SOCKET s);
38 : :
39 : : /**
40 : : * Copy constructor, disabled because closing the same socket twice is undesirable.
41 : : */
42 : : Sock(const Sock&) = delete;
43 : :
44 : : /**
45 : : * Move constructor, grab the socket from another object and close ours (if set).
46 : : */
47 : : Sock(Sock&& other);
48 : :
49 : : /**
50 : : * Destructor, close the socket or do nothing if empty.
51 : : */
52 : : virtual ~Sock();
53 : :
54 : : /**
55 : : * Copy assignment operator, disabled because closing the same socket twice is undesirable.
56 : : */
57 : : Sock& operator=(const Sock&) = delete;
58 : :
59 : : /**
60 : : * Move assignment operator, grab the socket from another object and close ours (if set).
61 : : */
62 : : virtual Sock& operator=(Sock&& other);
63 : :
64 : : /**
65 : : * send(2) wrapper. Equivalent to `send(m_socket, data, len, flags);`. Code that uses this
66 : : * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
67 : : */
68 : : [[nodiscard]] virtual ssize_t Send(const void* data, size_t len, int flags) const;
69 : :
70 : : /**
71 : : * recv(2) wrapper. Equivalent to `recv(m_socket, buf, len, flags);`. Code that uses this
72 : : * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
73 : : */
74 : : [[nodiscard]] virtual ssize_t Recv(void* buf, size_t len, int flags) const;
75 : :
76 : : /**
77 : : * connect(2) wrapper. Equivalent to `connect(m_socket, addr, addrlen)`. Code that uses this
78 : : * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
79 : : */
80 : : [[nodiscard]] virtual int Connect(const sockaddr* addr, socklen_t addr_len) const;
81 : :
82 : : /**
83 : : * bind(2) wrapper. Equivalent to `bind(m_socket, addr, addr_len)`. Code that uses this
84 : : * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
85 : : */
86 : : [[nodiscard]] virtual int Bind(const sockaddr* addr, socklen_t addr_len) const;
87 : :
88 : : /**
89 : : * listen(2) wrapper. Equivalent to `listen(m_socket, backlog)`. Code that uses this
90 : : * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
91 : : */
92 : : [[nodiscard]] virtual int Listen(int backlog) const;
93 : :
94 : : /**
95 : : * accept(2) wrapper. Equivalent to `std::make_unique<Sock>(accept(m_socket, addr, addr_len))`.
96 : : * Code that uses this wrapper can be unit tested if this method is overridden by a mock Sock
97 : : * implementation.
98 : : * The returned unique_ptr is empty if `accept()` failed in which case errno will be set.
99 : : */
100 : : [[nodiscard]] virtual std::unique_ptr<Sock> Accept(sockaddr* addr, socklen_t* addr_len) const;
101 : :
102 : : /**
103 : : * getsockopt(2) wrapper. Equivalent to
104 : : * `getsockopt(m_socket, level, opt_name, opt_val, opt_len)`. Code that uses this
105 : : * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
106 : : */
107 : : [[nodiscard]] virtual int GetSockOpt(int level,
108 : : int opt_name,
109 : : void* opt_val,
110 : : socklen_t* opt_len) const;
111 : :
112 : : /**
113 : : * setsockopt(2) wrapper. Equivalent to
114 : : * `setsockopt(m_socket, level, opt_name, opt_val, opt_len)`. Code that uses this
115 : : * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
116 : : */
117 : : [[nodiscard]] virtual int SetSockOpt(int level,
118 : : int opt_name,
119 : : const void* opt_val,
120 : : socklen_t opt_len) const;
121 : :
122 : : /**
123 : : * getsockname(2) wrapper. Equivalent to
124 : : * `getsockname(m_socket, name, name_len)`. Code that uses this
125 : : * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
126 : : */
127 : : [[nodiscard]] virtual int GetSockName(sockaddr* name, socklen_t* name_len) const;
128 : :
129 : : /**
130 : : * Set the non-blocking option on the socket.
131 : : * @return true if set successfully
132 : : */
133 : : [[nodiscard]] virtual bool SetNonBlocking() const;
134 : :
135 : : /**
136 : : * Check if the underlying socket can be used for `select(2)` (or the `Wait()` method).
137 : : * @return true if selectable
138 : : */
139 : : [[nodiscard]] virtual bool IsSelectable() const;
140 : :
141 : : using Event = uint8_t;
142 : :
143 : : /**
144 : : * If passed to `Wait()`, then it will wait for readiness to read from the socket.
145 : : */
146 : : static constexpr Event RECV = 0b001;
147 : :
148 : : /**
149 : : * If passed to `Wait()`, then it will wait for readiness to send to the socket.
150 : : */
151 : : static constexpr Event SEND = 0b010;
152 : :
153 : : /**
154 : : * Ignored if passed to `Wait()`, but could be set in the occurred events if an
155 : : * exceptional condition has occurred on the socket or if it has been disconnected.
156 : : */
157 : : static constexpr Event ERR = 0b100;
158 : :
159 : : /**
160 : : * Wait for readiness for input (recv) or output (send).
161 : : * @param[in] timeout Wait this much for at least one of the requested events to occur.
162 : : * @param[in] requested Wait for those events, bitwise-or of `RECV` and `SEND`.
163 : : * @param[out] occurred If not nullptr and the function returns `true`, then this
164 : : * indicates which of the requested events occurred (`ERR` will be added, even if
165 : : * not requested, if an exceptional event occurs on the socket).
166 : : * A timeout is indicated by return value of `true` and `occurred` being set to 0.
167 : : * @return true on success (or timeout, if `occurred` of 0 is returned), false otherwise
168 : : */
169 : : [[nodiscard]] virtual bool Wait(std::chrono::milliseconds timeout,
170 : : Event requested,
171 : : Event* occurred = nullptr) const;
172 : :
173 : : /**
174 : : * Auxiliary requested/occurred events to wait for in `WaitMany()`.
175 : : */
176 : : struct Events {
177 [ # # ]: 1073831 : explicit Events(Event req) : requested{req} {}
[ + - + - ]
178 : : Event requested;
179 : : Event occurred{0};
180 : : };
181 : :
182 : : struct HashSharedPtrSock {
183 : 1085805 : size_t operator()(const std::shared_ptr<const Sock>& s) const
184 : : {
185 [ + - ]: 1085805 : return s ? s->m_socket : std::numeric_limits<SOCKET>::max();
186 : : }
187 : : };
188 : :
189 : : struct EqualSharedPtrSock {
190 : 1077026 : bool operator()(const std::shared_ptr<const Sock>& lhs,
191 : : const std::shared_ptr<const Sock>& rhs) const
192 : : {
193 [ + - + - ]: 1077026 : if (lhs && rhs) {
194 : 1077026 : return lhs->m_socket == rhs->m_socket;
195 : : }
196 [ # # # # ]: 0 : if (!lhs && !rhs) {
197 : 0 : return true;
198 : : }
199 : : return false;
200 : : }
201 : : };
202 : :
203 : : /**
204 : : * On which socket to wait for what events in `WaitMany()`.
205 : : * The `shared_ptr` is copied into the map to ensure that the `Sock` object
206 : : * is not destroyed (its destructor would close the underlying socket).
207 : : * If this happens shortly before or after we call `poll(2)` and a new
208 : : * socket gets created under the same file descriptor number then the report
209 : : * from `WaitMany()` will be bogus.
210 : : */
211 : : using EventsPerSock = std::unordered_map<std::shared_ptr<const Sock>, Events, HashSharedPtrSock, EqualSharedPtrSock>;
212 : :
213 : : /**
214 : : * Same as `Wait()`, but wait on many sockets within the same timeout.
215 : : * @param[in] timeout Wait this long for at least one of the requested events to occur.
216 : : * @param[in,out] events_per_sock Wait for the requested events on these sockets and set
217 : : * `occurred` for the events that actually occurred.
218 : : * @return true on success (or timeout, if all `what[].occurred` are returned as 0),
219 : : * false otherwise
220 : : */
221 : : [[nodiscard]] virtual bool WaitMany(std::chrono::milliseconds timeout,
222 : : EventsPerSock& events_per_sock) const;
223 : :
224 : : /* Higher level, convenience, methods. These may throw. */
225 : :
226 : : /**
227 : : * Send the given data, retrying on transient errors.
228 : : * @param[in] data Data to send.
229 : : * @param[in] timeout Timeout for the entire operation.
230 : : * @param[in] interrupt If this is signaled then the operation is canceled.
231 : : * @throws std::runtime_error if the operation cannot be completed. In this case only some of
232 : : * the data will be written to the socket.
233 : : */
234 : : virtual void SendComplete(std::span<const unsigned char> data,
235 : : std::chrono::milliseconds timeout,
236 : : CThreadInterrupt& interrupt) const;
237 : :
238 : : /**
239 : : * Convenience method, equivalent to `SendComplete(MakeUCharSpan(data), timeout, interrupt)`.
240 : : */
241 : : virtual void SendComplete(std::span<const char> data,
242 : : std::chrono::milliseconds timeout,
243 : : CThreadInterrupt& interrupt) const;
244 : :
245 : : /**
246 : : * Read from socket until a terminator character is encountered. Will never consume bytes past
247 : : * the terminator from the socket.
248 : : * @param[in] terminator Character up to which to read from the socket.
249 : : * @param[in] timeout Timeout for the entire operation.
250 : : * @param[in] interrupt If this is signaled then the operation is canceled.
251 : : * @param[in] max_data The maximum amount of data (in bytes) to receive. If this many bytes
252 : : * are received and there is still no terminator, then this method will throw an exception.
253 : : * @return The data that has been read, without the terminating character.
254 : : * @throws std::runtime_error if the operation cannot be completed. In this case some bytes may
255 : : * have been consumed from the socket.
256 : : */
257 : : [[nodiscard]] virtual std::string RecvUntilTerminator(uint8_t terminator,
258 : : std::chrono::milliseconds timeout,
259 : : CThreadInterrupt& interrupt,
260 : : size_t max_data) const;
261 : :
262 : : /**
263 : : * Check if still connected.
264 : : * @param[out] errmsg The error string, if the socket has been disconnected.
265 : : * @return true if connected
266 : : */
267 : : [[nodiscard]] virtual bool IsConnected(std::string& errmsg) const;
268 : :
269 : : /**
270 : : * Check if the internal socket is equal to `s`. Use only in tests.
271 : : */
272 : : bool operator==(SOCKET s) const;
273 : :
274 : : protected:
275 : : /**
276 : : * Contained socket. `INVALID_SOCKET` designates the object is empty.
277 : : */
278 : : SOCKET m_socket;
279 : :
280 : : private:
281 : : /**
282 : : * Close `m_socket` if it is not `INVALID_SOCKET`.
283 : : */
284 : : void Close();
285 : : };
286 : :
287 : : /** Return readable error string for a network error code */
288 : : std::string NetworkErrorString(int err);
289 : :
290 : : #endif // BITCOIN_UTIL_SOCK_H
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