//===-- RNBSocket.cpp -------------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  Created by Greg Clayton on 12/12/07.
//
//===----------------------------------------------------------------------===//

#include "RNBSocket.h"
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <termios.h>
#include "DNBLog.h"
#include "DNBError.h"

#ifdef WITH_LOCKDOWN
#include "lockdown.h"
#endif

/* Once we have a RNBSocket object with a port # specified,
   this function is called to wait for an incoming connection.
   This function blocks while waiting for that connection.  */

bool
ResolveIPV4HostName (const char *hostname, in_addr_t &addr)
{
    if (hostname == NULL ||
        hostname[0] == '\0' ||
        strcmp(hostname, "localhost") == 0 ||
        strcmp(hostname, "127.0.0.1") == 0)
    {
        addr = htonl (INADDR_LOOPBACK);
        return true;
    }
    else if (strcmp(hostname, "*") == 0)
    {
        addr = htonl (INADDR_ANY);
        return true;
    }
    else
    {
        // See if an IP address was specified as numbers
        int inet_pton_result = ::inet_pton (AF_INET, hostname, &addr);

        if (inet_pton_result == 1)
            return true;
        
        struct hostent *host_entry = gethostbyname (hostname);
        if (host_entry)
        {
            std::string ip_str (::inet_ntoa (*(struct in_addr *)*host_entry->h_addr_list));
            inet_pton_result = ::inet_pton (AF_INET, ip_str.c_str(), &addr);
            if (inet_pton_result == 1)
                return true;
        }
    }
    return false;
}

rnb_err_t
RNBSocket::Listen (const char *listen_host, in_port_t port, PortBoundCallback callback, const void *callback_baton)
{
    //DNBLogThreadedIf(LOG_RNB_COMM, "%8u RNBSocket::%s called", (uint32_t)m_timer.ElapsedMicroSeconds(true), __FUNCTION__);
    // Disconnect without saving errno
    Disconnect (false);

    // Now figure out the hostname that will be attaching and palce it into
    struct sockaddr_in listen_addr;
    ::memset (&listen_addr, 0, sizeof listen_addr);
    listen_addr.sin_len = sizeof listen_addr;
    listen_addr.sin_family = AF_INET;
    listen_addr.sin_port = htons (port);
    listen_addr.sin_addr.s_addr = INADDR_ANY;
    
    if (!ResolveIPV4HostName(listen_host, listen_addr.sin_addr.s_addr))
    {
        DNBLogThreaded("error: failed to resolve connecting host '%s'", listen_host);
        return rnb_err;
    }
    
    DNBError err;
    int listen_fd = ::socket (AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (listen_fd == -1)
        err.SetError(errno, DNBError::POSIX);

    if (err.Fail() || DNBLogCheckLogBit(LOG_RNB_COMM))
        err.LogThreaded("::socket ( domain = AF_INET, type = SOCK_STREAM, protocol = IPPROTO_TCP ) => socket = %i", listen_fd);

    if (err.Fail())
        return rnb_err;

    // enable local address reuse
    SetSocketOption (listen_fd, SOL_SOCKET, SO_REUSEADDR, 1);

    struct sockaddr_in sa;
    ::memset (&sa, 0, sizeof sa);
    sa.sin_len = sizeof sa;
    sa.sin_family = AF_INET;
    sa.sin_port = htons (port);
    sa.sin_addr.s_addr = INADDR_ANY; // Let incoming connections bind to any host network interface (this is NOT who can connect to us)
    int error = ::bind (listen_fd, (struct sockaddr *) &sa, sizeof(sa));
    if (error == -1)
        err.SetError(errno, DNBError::POSIX);

    if (err.Fail() || DNBLogCheckLogBit(LOG_RNB_COMM))
        err.LogThreaded("::bind ( socket = %i, (struct sockaddr *) &sa, sizeof(sa)) )", listen_fd);

    if (err.Fail())
    {
        ClosePort (listen_fd, false);
        return rnb_err;
    }

    if (callback && port == 0)
    {
        // We were asked to listen on port zero which means we
        // must now read the actual port that was given to us 
        // as port zero is a special code for "find an open port
        // for me".
        socklen_t sa_len = sizeof (sa);
        if (getsockname(listen_fd, (struct sockaddr *)&sa, &sa_len) == 0)
        {
            port = ntohs (sa.sin_port);
            callback (callback_baton, port);
        }
    }

    error = ::listen (listen_fd, 5);
    if (error == -1)
        err.SetError(errno, DNBError::POSIX);

    if (err.Fail() || DNBLogCheckLogBit(LOG_RNB_COMM))
        err.LogThreaded("::listen ( socket = %i, backlog = 1 )", listen_fd);

    if (err.Fail())
    {
        ClosePort (listen_fd, false);
        return rnb_err;
    }

    struct sockaddr_in accept_addr;
    ::memset (&accept_addr, 0, sizeof accept_addr);
    accept_addr.sin_len = sizeof accept_addr;

    bool accept_connection = false;

    // Loop until we are happy with our connection
    while (!accept_connection)
    {
        socklen_t accept_addr_len = sizeof accept_addr;
        m_fd = ::accept (listen_fd, (struct sockaddr *)&accept_addr, &accept_addr_len);

        if (m_fd == -1)
            err.SetError(errno, DNBError::POSIX);
        
        if (err.Fail() || DNBLogCheckLogBit(LOG_RNB_COMM))
            err.LogThreaded("::accept ( socket = %i, address = %p, address_len = %u )", listen_fd, &accept_addr, accept_addr_len);

        if (err.Fail())
            break;

        if (listen_addr.sin_addr.s_addr == INADDR_ANY)
            accept_connection = true;
        else
        {
            if (accept_addr_len == listen_addr.sin_len &&
                accept_addr.sin_addr.s_addr == listen_addr.sin_addr.s_addr)
            {
                accept_connection = true;
            }
            else
            {
                ::close (m_fd);
                m_fd = -1;
                const uint8_t *accept_ip = (const uint8_t *)&accept_addr.sin_addr.s_addr;
                const uint8_t *listen_ip = (const uint8_t *)&listen_addr.sin_addr.s_addr;
                ::fprintf (stderr,
                           "error: rejecting incoming connection from %u.%u.%u.%u (expecting %u.%u.%u.%u)\n",
                           accept_ip[0], accept_ip[1], accept_ip[2], accept_ip[3],
                           listen_ip[0], listen_ip[1], listen_ip[2], listen_ip[3]);
                DNBLogThreaded ("error: rejecting connection from %u.%u.%u.%u (expecting %u.%u.%u.%u)",
                                accept_ip[0], accept_ip[1], accept_ip[2], accept_ip[3],
                                listen_ip[0], listen_ip[1], listen_ip[2], listen_ip[3]);
            }
        }
    }

    ClosePort (listen_fd, false);

    if (err.Fail())
    {
        return rnb_err;
    }
    else
    {
        // Keep our TCP packets coming without any delays.
        SetSocketOption (m_fd, IPPROTO_TCP, TCP_NODELAY, 1);
    }

    return rnb_success;
}

rnb_err_t
RNBSocket::Connect (const char *host, uint16_t port)
{
    Disconnect (false);

    // Create the socket
    m_fd = ::socket (AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (m_fd == -1)
        return rnb_err;
    
    // Enable local address reuse
    SetSocketOption (m_fd, SOL_SOCKET, SO_REUSEADDR, 1);
    
    struct sockaddr_in sa;
    ::memset (&sa, 0, sizeof (sa));
    sa.sin_family = AF_INET;
    sa.sin_port = htons (port);
    
    if (!ResolveIPV4HostName(host, sa.sin_addr.s_addr))
    {
        DNBLogThreaded("error: failed to resolve host '%s'", host);
        Disconnect (false);
        return rnb_err;
    }
    
    if (-1 == ::connect (m_fd, (const struct sockaddr *)&sa, sizeof(sa)))
    {
        Disconnect (false);
        return rnb_err;
    }
    
    // Keep our TCP packets coming without any delays.
    SetSocketOption (m_fd, IPPROTO_TCP, TCP_NODELAY, 1);
    return rnb_success;
}

rnb_err_t
RNBSocket::useFD(int fd)
{
       if (fd < 0) {
               DNBLogThreadedIf(LOG_RNB_COMM, "Bad file descriptor passed in.");
               return rnb_err;
       }
       
       m_fd = fd;
       return rnb_success;
}

#ifdef WITH_LOCKDOWN
rnb_err_t
RNBSocket::ConnectToService()
{
    DNBLog("Connecting to com.apple.%s service...", DEBUGSERVER_PROGRAM_NAME);
    // Disconnect from any previous connections
    Disconnect(false);
    if (::secure_lockdown_checkin (&m_ld_conn, NULL, NULL) != kLDESuccess)
    {
        DNBLogThreadedIf(LOG_RNB_COMM, "::secure_lockdown_checkin(&m_fd, NULL, NULL) failed");
        m_fd = -1;
        return rnb_not_connected;
    }
    m_fd = ::lockdown_get_socket (m_ld_conn);
    if (m_fd == -1)
    {
        DNBLogThreadedIf(LOG_RNB_COMM, "::lockdown_get_socket() failed");
        return rnb_not_connected;
    }
    m_fd_from_lockdown = true;
    return rnb_success;
}
#endif

rnb_err_t
RNBSocket::OpenFile (const char *path)
{
    DNBError err;
    m_fd = open (path, O_RDWR);
    if (m_fd == -1)
    {
        err.SetError(errno, DNBError::POSIX);
        err.LogThreaded ("can't open file '%s'", path);
        return rnb_not_connected;
    }
    else
    {
        struct termios stdin_termios;

        if (::tcgetattr (m_fd, &stdin_termios) == 0)
        {
            stdin_termios.c_lflag &= ~ECHO;     // Turn off echoing
            stdin_termios.c_lflag &= ~ICANON;   // Get one char at a time
            ::tcsetattr (m_fd, TCSANOW, &stdin_termios);
        }
    }
    return rnb_success;
}

int
RNBSocket::SetSocketOption(int fd, int level, int option_name, int option_value)
{
    return ::setsockopt(fd, level, option_name, &option_value, sizeof(option_value));
}

rnb_err_t
RNBSocket::Disconnect (bool save_errno)
{
#ifdef WITH_LOCKDOWN
    if (m_fd_from_lockdown)
    {
        m_fd_from_lockdown = false;
        m_fd = -1;
        lockdown_disconnect (m_ld_conn);
        return rnb_success;
    }
#endif
    return ClosePort (m_fd, save_errno);
}


rnb_err_t
RNBSocket::Read (std::string &p)
{
    char buf[1024];
    p.clear();

    // Note that BUF is on the stack so we must be careful to keep any
    // writes to BUF from overflowing or we'll have security issues.

    if (m_fd == -1)
        return rnb_err;

    //DNBLogThreadedIf(LOG_RNB_COMM, "%8u RNBSocket::%s calling read()", (uint32_t)m_timer.ElapsedMicroSeconds(true), __FUNCTION__);
    DNBError err;
    int bytesread = read (m_fd, buf, sizeof (buf));
    if (bytesread <= 0)
        err.SetError(errno, DNBError::POSIX);
    else
        p.append(buf, bytesread);

    if (err.Fail() || DNBLogCheckLogBit(LOG_RNB_COMM))
        err.LogThreaded("::read ( %i, %p, %llu ) => %i", m_fd, buf, sizeof (buf), (uint64_t)bytesread);

    // Our port went away - we have to mark this so IsConnected will return the truth.
    if (bytesread == 0)
    {
        m_fd = -1;
        return rnb_not_connected;
    }
    else if (bytesread == -1)
    {
        m_fd = -1;
        return rnb_err;
    }
    // Strip spaces from the end of the buffer
    while (!p.empty() && isspace (p[p.size() - 1]))
        p.erase (p.size () - 1);

    // Most data in the debugserver packets valid printable characters...
    DNBLogThreadedIf(LOG_RNB_COMM, "read: %s", p.c_str());
    return rnb_success;
}

rnb_err_t
RNBSocket::Write (const void *buffer, size_t length)
{
    if (m_fd == -1)
        return rnb_err;

    DNBError err;
    int bytessent = write (m_fd, buffer, length);
    if (bytessent < 0)
        err.SetError(errno, DNBError::POSIX);

    if (err.Fail() || DNBLogCheckLogBit(LOG_RNB_COMM))
        err.LogThreaded("::write ( socket = %i, buffer = %p, length = %llu) => %i", m_fd, buffer, length, (uint64_t)bytessent);

    if (bytessent < 0)
        return rnb_err;

    if (bytessent != length)
        return rnb_err;

    DNBLogThreadedIf(LOG_RNB_PACKETS, "putpkt: %*s", (int)length, (char *)buffer);   // All data is string based in debugserver, so this is safe
    DNBLogThreadedIf(LOG_RNB_COMM, "sent: %*s", (int)length, (char *)buffer);

    return rnb_success;
}


rnb_err_t
RNBSocket::ClosePort (int& fd, bool save_errno)
{
    int close_err = 0;
    if (fd > 0)
    {
        errno = 0;
        close_err = close (fd);
        fd = -1;
    }
    return close_err != 0 ? rnb_err : rnb_success;
}