LCOV - code coverage report
Current view: top level - src/util - sock.h (source / functions) Hit Total Coverage
Test: fuzz_coverage.info Lines: 8 11 72.7 %
Date: 2023-11-06 23:13:05 Functions: 3 3 100.0 %
Branches: 3 10 30.0 %

           Branch data     Line data    Source code
       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                 :        340 :         explicit Events(Event req) : requested{req} {}
     175                 :            :         Event requested;
     176                 :        170 :         Event occurred{0};
     177                 :            :     };
     178                 :            : 
     179                 :            :     struct HashSharedPtrSock {
     180                 :        340 :         size_t operator()(const std::shared_ptr<const Sock>& s) const
     181                 :            :         {
     182         [ +  - ]:        340 :             return s ? s->m_socket : std::numeric_limits<SOCKET>::max();
     183                 :            :         }
     184                 :            :     };
     185                 :            : 
     186                 :            :     struct EqualSharedPtrSock {
     187                 :        170 :         bool operator()(const std::shared_ptr<const Sock>& lhs,
     188                 :            :                         const std::shared_ptr<const Sock>& rhs) const
     189                 :            :         {
     190 [ +  - ][ -  + ]:        170 :             if (lhs && rhs) {
     191                 :        170 :                 return lhs->m_socket == rhs->m_socket;
     192                 :            :             }
     193 [ #  # ][ #  # ]:          0 :             if (!lhs && !rhs) {
     194                 :          0 :                 return true;
     195                 :            :             }
     196                 :          0 :             return false;
     197                 :        170 :         }
     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(const std::string& data,
     232                 :            :                               std::chrono::milliseconds timeout,
     233                 :            :                               CThreadInterrupt& interrupt) const;
     234                 :            : 
     235                 :            :     /**
     236                 :            :      * Read from socket until a terminator character is encountered. Will never consume bytes past
     237                 :            :      * the terminator from the socket.
     238                 :            :      * @param[in] terminator Character up to which to read from the socket.
     239                 :            :      * @param[in] timeout Timeout for the entire operation.
     240                 :            :      * @param[in] interrupt If this is signaled then the operation is canceled.
     241                 :            :      * @param[in] max_data The maximum amount of data (in bytes) to receive. If this many bytes
     242                 :            :      * are received and there is still no terminator, then this method will throw an exception.
     243                 :            :      * @return The data that has been read, without the terminating character.
     244                 :            :      * @throws std::runtime_error if the operation cannot be completed. In this case some bytes may
     245                 :            :      * have been consumed from the socket.
     246                 :            :      */
     247                 :            :     [[nodiscard]] virtual std::string RecvUntilTerminator(uint8_t terminator,
     248                 :            :                                                           std::chrono::milliseconds timeout,
     249                 :            :                                                           CThreadInterrupt& interrupt,
     250                 :            :                                                           size_t max_data) const;
     251                 :            : 
     252                 :            :     /**
     253                 :            :      * Check if still connected.
     254                 :            :      * @param[out] errmsg The error string, if the socket has been disconnected.
     255                 :            :      * @return true if connected
     256                 :            :      */
     257                 :            :     [[nodiscard]] virtual bool IsConnected(std::string& errmsg) const;
     258                 :            : 
     259                 :            :     /**
     260                 :            :      * Check if the internal socket is equal to `s`. Use only in tests.
     261                 :            :      */
     262                 :            :     bool operator==(SOCKET s) const;
     263                 :            : 
     264                 :            : protected:
     265                 :            :     /**
     266                 :            :      * Contained socket. `INVALID_SOCKET` designates the object is empty.
     267                 :            :      */
     268                 :            :     SOCKET m_socket;
     269                 :            : 
     270                 :            : private:
     271                 :            :     /**
     272                 :            :      * Close `m_socket` if it is not `INVALID_SOCKET`.
     273                 :            :      */
     274                 :            :     void Close();
     275                 :            : };
     276                 :            : 
     277                 :            : /** Return readable error string for a network error code */
     278                 :            : std::string NetworkErrorString(int err);
     279                 :            : 
     280                 :            : #endif // BITCOIN_UTIL_SOCK_H

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