/tmp/bitcoin/src/util/sock.h

Source
// Copyright (c) 2020-present The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_UTIL_SOCK_H
#define BITCOIN_UTIL_SOCK_H

#include <compat/compat.h>
#include <util/time.h>

#include <cstdint>
#include <limits>
#include <memory>
#include <span>
#include <string>
#include <unordered_map>

class CThreadInterrupt;

/**
 * Maximum time to wait for I/O readiness.
 * It will take up until this time to break off in case of an interruption.
 */
static constexpr auto MAX_WAIT_FOR_IO = 1s;

/**
 * RAII helper class that manages a socket and closes it automatically when it goes out of scope.
 */
class Sock
{
public:
    Sock() = delete;

    /**
     * Take ownership of an existent socket.
     */
    explicit Sock(SOCKET s);

    /**
     * Copy constructor, disabled because closing the same socket twice is undesirable.
     */
    Sock(const Sock&) = delete;

    /**
     * Move constructor, grab the socket from another object and close ours (if set).
     */
    Sock(Sock&& other);

    /**
     * Destructor, close the socket or do nothing if empty.
     */
    virtual ~Sock();

    /**
     * Copy assignment operator, disabled because closing the same socket twice is undesirable.
     */
    Sock& operator=(const Sock&) = delete;

    /**
     * Move assignment operator, grab the socket from another object and close ours (if set).
     */
    virtual Sock& operator=(Sock&& other);

    /**
     * send(2) wrapper. Equivalent to `send(m_socket, data, len, flags);`. Code that uses this
     * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
     */
    [[nodiscard]] virtual ssize_t Send(const void* data, size_t len, int flags) const;

    /**
     * recv(2) wrapper. Equivalent to `recv(m_socket, buf, len, flags);`. Code that uses this
     * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
     */
    [[nodiscard]] virtual ssize_t Recv(void* buf, size_t len, int flags) const;

    /**
     * connect(2) wrapper. Equivalent to `connect(m_socket, addr, addrlen)`. Code that uses this
     * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
     */
    [[nodiscard]] virtual int Connect(const sockaddr* addr, socklen_t addr_len) const;

    /**
     * bind(2) wrapper. Equivalent to `bind(m_socket, addr, addr_len)`. Code that uses this
     * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
     */
    [[nodiscard]] virtual int Bind(const sockaddr* addr, socklen_t addr_len) const;

    /**
     * listen(2) wrapper. Equivalent to `listen(m_socket, backlog)`. Code that uses this
     * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
     */
    [[nodiscard]] virtual int Listen(int backlog) const;

    /**
     * accept(2) wrapper. Equivalent to `std::make_unique<Sock>(accept(m_socket, addr, addr_len))`.
     * Code that uses this wrapper can be unit tested if this method is overridden by a mock Sock
     * implementation.
     * The returned unique_ptr is empty if `accept()` failed in which case errno will be set.
     */
    [[nodiscard]] virtual std::unique_ptr<Sock> Accept(sockaddr* addr, socklen_t* addr_len) const;

    /**
     * getsockopt(2) wrapper. Equivalent to
     * `getsockopt(m_socket, level, opt_name, opt_val, opt_len)`. Code that uses this
     * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
     */
    [[nodiscard]] virtual int GetSockOpt(int level,
                                         int opt_name,
                                         void* opt_val,
                                         socklen_t* opt_len) const;

    /**
     * setsockopt(2) wrapper. Equivalent to
     * `setsockopt(m_socket, level, opt_name, opt_val, opt_len)`. Code that uses this
     * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
     */
    [[nodiscard]] virtual int SetSockOpt(int level,
                                         int opt_name,
                                         const void* opt_val,
                                         socklen_t opt_len) const;

    /**
     * getsockname(2) wrapper. Equivalent to
     * `getsockname(m_socket, name, name_len)`. Code that uses this
     * wrapper can be unit tested if this method is overridden by a mock Sock implementation.
     */
    [[nodiscard]] virtual int GetSockName(sockaddr* name, socklen_t* name_len) const;

    /**
     * Set the non-blocking option on the socket.
     * @return true if set successfully
     */
    [[nodiscard]] virtual bool SetNonBlocking() const;

    /**
     * Check if the underlying socket can be used for `select(2)` (or the `Wait()` method).
     * @return true if selectable
     */
    [[nodiscard]] virtual bool IsSelectable() const;

    using Event = uint8_t;

    /**
     * If passed to `Wait()`, then it will wait for readiness to read from the socket.
     */
    static constexpr Event RECV = 0b001;

    /**
     * If passed to `Wait()`, then it will wait for readiness to send to the socket.
     */
    static constexpr Event SEND = 0b010;

    /**
     * Ignored if passed to `Wait()`, but could be set in the occurred events if an
     * exceptional condition has occurred on the socket or if it has been disconnected.
     */
    static constexpr Event ERR = 0b100;

    /**
     * Wait for readiness for input (recv) or output (send).
     * @param[in] timeout Wait this much for at least one of the requested events to occur.
     * @param[in] requested Wait for those events, bitwise-or of `RECV` and `SEND`.
     * @param[out] occurred If not nullptr and the function returns `true`, then this
     * indicates which of the requested events occurred (`ERR` will be added, even if
     * not requested, if an exceptional event occurs on the socket).
     * A timeout is indicated by return value of `true` and `occurred` being set to 0.
     * @return true on success (or timeout, if `occurred` of 0 is returned), false otherwise
     */
    [[nodiscard]] virtual bool Wait(std::chrono::milliseconds timeout,
                                    Event requested,
                                    Event* occurred = nullptr) const;

    /**
     * Auxiliary requested/occurred events to wait for in `WaitMany()`.
     */
    struct Events {
        explicit Events(Event req) : requested{req} {}
        Event requested;
        Event occurred{0};
    };

    struct HashSharedPtrSock {
        size_t operator()(const std::shared_ptr<const Sock>& s) const
        {
            return s ? s->m_socket : std::numeric_limits<SOCKET>::max();
        }
    };

    struct EqualSharedPtrSock {
        bool operator()(const std::shared_ptr<const Sock>& lhs,
                        const std::shared_ptr<const Sock>& rhs) const
        {
            if (lhs && rhs) {
                return lhs->m_socket == rhs->m_socket;
            }
            if (!lhs && !rhs) {
                return true;
            }
            return false;
        }
    };

    /**
     * On which socket to wait for what events in `WaitMany()`.
     * The `shared_ptr` is copied into the map to ensure that the `Sock` object
     * is not destroyed (its destructor would close the underlying socket).
     * If this happens shortly before or after we call `poll(2)` and a new
     * socket gets created under the same file descriptor number then the report
     * from `WaitMany()` will be bogus.
     */
    using EventsPerSock = std::unordered_map<std::shared_ptr<const Sock>, Events, HashSharedPtrSock, EqualSharedPtrSock>;

    /**
     * Same as `Wait()`, but wait on many sockets within the same timeout.
     * @param[in] timeout Wait this long for at least one of the requested events to occur.
     * @param[in,out] events_per_sock Wait for the requested events on these sockets and set
     * `occurred` for the events that actually occurred.
     * @return true on success (or timeout, if all `what[].occurred` are returned as 0),
     * false otherwise
     */
    [[nodiscard]] virtual bool WaitMany(std::chrono::milliseconds timeout,
                                        EventsPerSock& events_per_sock) const;

    /* Higher level, convenience, methods. These may throw. */

    /**
     * Send the given data, retrying on transient errors.
     * @param[in] data Data to send.
     * @param[in] timeout Timeout for the entire operation.
     * @param[in] interrupt If this is signaled then the operation is canceled.
     * @throws std::runtime_error if the operation cannot be completed. In this case only some of
     * the data will be written to the socket.
     */
    virtual void SendComplete(std::span<const unsigned char> data,
                              std::chrono::milliseconds timeout,
                              CThreadInterrupt& interrupt) const;

    /**
     * Convenience method, equivalent to `SendComplete(MakeUCharSpan(data), timeout, interrupt)`.
     */
    virtual void SendComplete(std::span<const char> data,
                              std::chrono::milliseconds timeout,
                              CThreadInterrupt& interrupt) const;

    /**
     * Read from socket until a terminator character is encountered. Will never consume bytes past
     * the terminator from the socket.
     * @param[in] terminator Character up to which to read from the socket.
     * @param[in] timeout Timeout for the entire operation.
     * @param[in] interrupt If this is signaled then the operation is canceled.
     * @param[in] max_data The maximum amount of data (in bytes) to receive. If this many bytes
     * are received and there is still no terminator, then this method will throw an exception.
     * @return The data that has been read, without the terminating character.
     * @throws std::runtime_error if the operation cannot be completed. In this case some bytes may
     * have been consumed from the socket.
     */
    [[nodiscard]] virtual std::string RecvUntilTerminator(uint8_t terminator,
                                                          std::chrono::milliseconds timeout,
                                                          CThreadInterrupt& interrupt,
                                                          size_t max_data) const;

    /**
     * Check if still connected.
     * @param[out] errmsg The error string, if the socket has been disconnected.
     * @return true if connected
     */
    [[nodiscard]] virtual bool IsConnected(std::string& errmsg) const;

    /**
     * Check if the internal socket is equal to `s`. Use only in tests.
     */
    bool operator==(SOCKET s) const;

protected:
    /**
     * Contained socket. `INVALID_SOCKET` designates the object is empty.
     */
    SOCKET m_socket;

private:
    /**
     * Close `m_socket` if it is not `INVALID_SOCKET`.
     */
    void Close();
};

/** Return readable error string for a network error code */
std::string NetworkErrorString(int err);

#endif // BITCOIN_UTIL_SOCK_H

Coverage Report

Created: 2026-04-29 19:21

Line	Count	Source
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	815k	explicit Events(Event req) : requested{req} {}
178		Event requested;
179		Event occurred{0};
180		};
181
182		struct HashSharedPtrSock {
183		size_t operator()(const std::shared_ptr<const Sock>& s) const
184	1.62M	{
185	1.62M	return s ? s->m_socket : std::numeric_limits<SOCKET>::max();
186	1.62M	}
187		};
188
189		struct EqualSharedPtrSock {
190		bool operator()(const std::shared_ptr<const Sock>& lhs,
191		const std::shared_ptr<const Sock>& rhs) const
192	813k	{
193	813k	if (lhs && rhs) {
194	813k	return lhs->m_socket == rhs->m_socket;
195	813k	}
196	0	if (!lhs && !rhs) {
197	0	return true;
198	0	}
199	0	return false;
200	0	}
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