Function CreateSockTCP

src/netbase.cpp:486–527

}

std::unique_ptr<Sock> CreateSockTCP(const CService& address_family)
{
    // Create a sockaddr from the specified service.
    struct sockaddr_storage sockaddr;
    socklen_t len = sizeof(sockaddr);
    if (!address_family.GetSockAddr((struct sockaddr*)&sockaddr, &len)) {
        LogPrintf("Cannot create socket for %s: unsupported network\n", address_family.ToString());
        return nullptr;
    }

    // Create a TCP socket in the address family of the specified service.
    SOCKET hSocket = socket(((struct sockaddr*)&sockaddr)->sa_family, SOCK_STREAM, IPPROTO_TCP);
    if (hSocket == INVALID_SOCKET) {
        return nullptr;
    }

    // Ensure that waiting for I/O on this socket won't result in undefined
    // behavior.
    if (!IsSelectableSocket(hSocket)) {
        CloseSocket(hSocket);
        LogPrintf("Cannot create connection: non-selectable socket created (fd >= FD_SETSIZE ?)\n");
        return nullptr;
    }

#ifdef SO_NOSIGPIPE
    int set = 1;
    // Set the no-sigpipe option on the socket for BSD systems, other UNIXes
    // should use the MSG_NOSIGNAL flag for every send.
    setsockopt(hSocket, SOL_SOCKET, SO_NOSIGPIPE, (void*)&set, sizeof(int));
#endif

    // Set the no-delay option (disable Nagle's algorithm) on the TCP socket.
    SetSocketNoDelay(hSocket);

    // Set the non-blocking option on the socket.
    if (!SetSocketNonBlocking(hSocket, true)) {
        CloseSocket(hSocket);
        LogPrintf("Error setting socket to non-blocking: %s\n", NetworkErrorString(WSAGetLastError()));
        return nullptr;
    }
    return std::make_unique<Sock>(hSocket);
}

std::function<std::unique_ptr<Sock>(const CService&)> CreateSock = CreateSockTCP;