/root/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/threadinterrupt.h>
#include <util/time.h>

#include <chrono>
#include <memory>
#include <span>
#include <string>
#include <unordered_map>

/**
 * 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

fuzz coverage

Coverage Report

Created: 2026-04-24 13:48

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