/root/bitcoin/src/util/sock.h

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// Copyright (c) 2020-2022 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 <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(Span<const unsigned char> data,
                              std::chrono::milliseconds timeout,
                              CThreadInterrupt& interrupt) const;

    /**
     * Convenience method, equivalent to `SendComplete(MakeUCharSpan(data), timeout, interrupt)`.
     */
    virtual void SendComplete(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: 2024-10-29 12:10

Line	Count	Source (jump to first uncovered line)
1		// Copyright (c) 2020-2022 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 <string>
15		#include <unordered_map>
16
17		/**
18		* Maximum time to wait for I/O readiness.
19		* It will take up until this time to break off in case of an interruption.
20		*/
21		static constexpr auto MAX_WAIT_FOR_IO = 1s;
22
23		/**
24		* RAII helper class that manages a socket and closes it automatically when it goes out of scope.
25		*/
26		class Sock
27		{
28		public:
29		Sock() = delete;
30
31		/**
32		* Take ownership of an existent socket.
33		*/
34		explicit Sock(SOCKET s);
35
36		/**
37		* Copy constructor, disabled because closing the same socket twice is undesirable.
38		*/
39		Sock(const Sock&) = delete;
40
41		/**
42		* Move constructor, grab the socket from another object and close ours (if set).
43		*/
44		Sock(Sock&& other);
45
46		/**
47		* Destructor, close the socket or do nothing if empty.
48		*/
49		virtual ~Sock();
50
51		/**
52		* Copy assignment operator, disabled because closing the same socket twice is undesirable.
53		*/
54		Sock& operator=(const Sock&) = delete;
55
56		/**
57		* Move assignment operator, grab the socket from another object and close ours (if set).
58		*/
59		virtual Sock& operator=(Sock&& other);
60
61		/**
62		* send(2) wrapper. Equivalent to `send(m_socket, data, len, flags);`. Code that uses this
63		* wrapper can be unit tested if this method is overridden by a mock Sock implementation.
64		*/
65		[[nodiscard]] virtual ssize_t Send(const void* data, size_t len, int flags) const;
66
67		/**
68		* recv(2) wrapper. Equivalent to `recv(m_socket, buf, len, flags);`. Code that uses this
69		* wrapper can be unit tested if this method is overridden by a mock Sock implementation.
70		*/
71		[[nodiscard]] virtual ssize_t Recv(void* buf, size_t len, int flags) const;
72
73		/**
74		* connect(2) wrapper. Equivalent to `connect(m_socket, addr, addrlen)`. Code that uses this
75		* wrapper can be unit tested if this method is overridden by a mock Sock implementation.
76		*/
77		[[nodiscard]] virtual int Connect(const sockaddr* addr, socklen_t addr_len) const;
78
79		/**
80		* bind(2) wrapper. Equivalent to `bind(m_socket, addr, addr_len)`. Code that uses this
81		* wrapper can be unit tested if this method is overridden by a mock Sock implementation.
82		*/
83		[[nodiscard]] virtual int Bind(const sockaddr* addr, socklen_t addr_len) const;
84
85		/**
86		* listen(2) wrapper. Equivalent to `listen(m_socket, backlog)`. Code that uses this
87		* wrapper can be unit tested if this method is overridden by a mock Sock implementation.
88		*/
89		[[nodiscard]] virtual int Listen(int backlog) const;
90
91		/**
92		* accept(2) wrapper. Equivalent to `std::make_unique<Sock>(accept(m_socket, addr, addr_len))`.
93		* Code that uses this wrapper can be unit tested if this method is overridden by a mock Sock
94		* implementation.
95		* The returned unique_ptr is empty if `accept()` failed in which case errno will be set.
96		*/
97		[[nodiscard]] virtual std::unique_ptr<Sock> Accept(sockaddr* addr, socklen_t* addr_len) const;
98
99		/**
100		* getsockopt(2) wrapper. Equivalent to
101		* `getsockopt(m_socket, level, opt_name, opt_val, opt_len)`. Code that uses this
102		* wrapper can be unit tested if this method is overridden by a mock Sock implementation.
103		*/
104		[[nodiscard]] virtual int GetSockOpt(int level,
105		int opt_name,
106		void* opt_val,
107		socklen_t* opt_len) const;
108
109		/**
110		* setsockopt(2) wrapper. Equivalent to
111		* `setsockopt(m_socket, level, opt_name, opt_val, opt_len)`. Code that uses this
112		* wrapper can be unit tested if this method is overridden by a mock Sock implementation.
113		*/
114		[[nodiscard]] virtual int SetSockOpt(int level,
115		int opt_name,
116		const void* opt_val,
117		socklen_t opt_len) const;
118
119		/**
120		* getsockname(2) wrapper. Equivalent to
121		* `getsockname(m_socket, name, name_len)`. Code that uses this
122		* wrapper can be unit tested if this method is overridden by a mock Sock implementation.
123		*/
124		[[nodiscard]] virtual int GetSockName(sockaddr* name, socklen_t* name_len) const;
125
126		/**
127		* Set the non-blocking option on the socket.
128		* @return true if set successfully
129		*/
130		[[nodiscard]] virtual bool SetNonBlocking() const;
131
132		/**
133		* Check if the underlying socket can be used for `select(2)` (or the `Wait()` method).
134		* @return true if selectable
135		*/
136		[[nodiscard]] virtual bool IsSelectable() const;
137
138		using Event = uint8_t;
139
140		/**
141		* If passed to `Wait()`, then it will wait for readiness to read from the socket.
142		*/
143		static constexpr Event RECV = 0b001;
144
145		/**
146		* If passed to `Wait()`, then it will wait for readiness to send to the socket.
147		*/
148		static constexpr Event SEND = 0b010;
149
150		/**
151		* Ignored if passed to `Wait()`, but could be set in the occurred events if an
152		* exceptional condition has occurred on the socket or if it has been disconnected.
153		*/
154		static constexpr Event ERR = 0b100;
155
156		/**
157		* Wait for readiness for input (recv) or output (send).
158		* @param[in] timeout Wait this much for at least one of the requested events to occur.
159		* @param[in] requested Wait for those events, bitwise-or of `RECV` and `SEND`.
160		* @param[out] occurred If not nullptr and the function returns `true`, then this
161		* indicates which of the requested events occurred (`ERR` will be added, even if
162		* not requested, if an exceptional event occurs on the socket).
163		* A timeout is indicated by return value of `true` and `occurred` being set to 0.
164		* @return true on success (or timeout, if `occurred` of 0 is returned), false otherwise
165		*/
166		[[nodiscard]] virtual bool Wait(std::chrono::milliseconds timeout,
167		Event requested,
168		Event* occurred = nullptr) const;
169
170		/**
171		* Auxiliary requested/occurred events to wait for in `WaitMany()`.
172		*/
173		struct Events {
174	0	explicit Events(Event req) : requested{req} {}
175		Event requested;
176		Event occurred{0};
177		};
178
179		struct HashSharedPtrSock {
180		size_t operator()(const std::shared_ptr<const Sock>& s) const
181	0	{
182	0	return s ? s->m_socket : std::numeric_limits<SOCKET>::max();
183	0	}
184		};
185
186		struct EqualSharedPtrSock {
187		bool operator()(const std::shared_ptr<const Sock>& lhs,
188		const std::shared_ptr<const Sock>& rhs) const
189	0	{
190	0	if (lhs && rhs) {
191	0	return lhs->m_socket == rhs->m_socket;
192	0	}
193	0	if (!lhs && !rhs) {
194	0	return true;
195	0	}
196	0	return false;
197	0	}
198		};
199
200		/**
201		* On which socket to wait for what events in `WaitMany()`.
202		* The `shared_ptr` is copied into the map to ensure that the `Sock` object
203		* is not destroyed (its destructor would close the underlying socket).
204		* If this happens shortly before or after we call `poll(2)` and a new
205		* socket gets created under the same file descriptor number then the report
206		* from `WaitMany()` will be bogus.
207		*/
208		using EventsPerSock = std::unordered_map<std::shared_ptr<const Sock>, Events, HashSharedPtrSock, EqualSharedPtrSock>;
209
210		/**
211		* Same as `Wait()`, but wait on many sockets within the same timeout.
212		* @param[in] timeout Wait this long for at least one of the requested events to occur.
213		* @param[in,out] events_per_sock Wait for the requested events on these sockets and set
214		* `occurred` for the events that actually occurred.
215		* @return true on success (or timeout, if all `what[].occurred` are returned as 0),
216		* false otherwise
217		*/
218		[[nodiscard]] virtual bool WaitMany(std::chrono::milliseconds timeout,
219		EventsPerSock& events_per_sock) const;
220
221		/* Higher level, convenience, methods. These may throw. */
222
223		/**
224		* Send the given data, retrying on transient errors.
225		* @param[in] data Data to send.
226		* @param[in] timeout Timeout for the entire operation.
227		* @param[in] interrupt If this is signaled then the operation is canceled.
228		* @throws std::runtime_error if the operation cannot be completed. In this case only some of
229		* the data will be written to the socket.
230		*/
231		virtual void SendComplete(Span<const unsigned char> data,
232		std::chrono::milliseconds timeout,
233		CThreadInterrupt& interrupt) const;
234
235		/**
236		* Convenience method, equivalent to `SendComplete(MakeUCharSpan(data), timeout, interrupt)`.
237		*/
238		virtual void SendComplete(Span<const char> data,
239		std::chrono::milliseconds timeout,
240		CThreadInterrupt& interrupt) const;
241
242		/**
243		* Read from socket until a terminator character is encountered. Will never consume bytes past
244		* the terminator from the socket.
245		* @param[in] terminator Character up to which to read from the socket.
246		* @param[in] timeout Timeout for the entire operation.
247		* @param[in] interrupt If this is signaled then the operation is canceled.
248		* @param[in] max_data The maximum amount of data (in bytes) to receive. If this many bytes
249		* are received and there is still no terminator, then this method will throw an exception.
250		* @return The data that has been read, without the terminating character.
251		* @throws std::runtime_error if the operation cannot be completed. In this case some bytes may
252		* have been consumed from the socket.
253		*/
254		[[nodiscard]] virtual std::string RecvUntilTerminator(uint8_t terminator,
255		std::chrono::milliseconds timeout,
256		CThreadInterrupt& interrupt,
257		size_t max_data) const;
258
259		/**
260		* Check if still connected.
261		* @param[out] errmsg The error string, if the socket has been disconnected.
262		* @return true if connected
263		*/
264		[[nodiscard]] virtual bool IsConnected(std::string& errmsg) const;
265
266		/**
267		* Check if the internal socket is equal to `s`. Use only in tests.
268		*/
269		bool operator==(SOCKET s) const;
270
271		protected:
272		/**
273		* Contained socket. `INVALID_SOCKET` designates the object is empty.
274		*/
275		SOCKET m_socket;
276
277		private:
278		/**
279		* Close `m_socket` if it is not `INVALID_SOCKET`.
280		*/
281		void Close();
282		};
283
284		/** Return readable error string for a network error code */
285		std::string NetworkErrorString(int err);
286
287		#endif // BITCOIN_UTIL_SOCK_H