/*****************************************************************************
 * io.c: network I/O functions
 *****************************************************************************
 * Copyright (C) 2004-2005, 2007 VLC authors and VideoLAN
 * Copyright © 2005-2006 Rémi Denis-Courmont
 * $Id: dc5ef1207f0938d5bd7ce7b0eb95406c91750fa1 $
 *
 * Authors: Laurent Aimar <fenrir@videolan.org>
 *          Rémi Denis-Courmont <rem # videolan.org>
 *          Christophe Mutricy <xtophe at videolan dot org>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <vlc_common.h>

#include <stdlib.h>
#include <stdio.h>
#include <limits.h>

#include <errno.h>
#include <assert.h>

#include <fcntl.h>
#ifdef HAVE_UNISTD_H
#   include <unistd.h>
#endif
#ifdef HAVE_POLL
#   include <poll.h>
#endif

#include <vlc_network.h>

#ifndef INADDR_ANY
#   define INADDR_ANY  0x00000000
#endif
#ifndef INADDR_NONE
#   define INADDR_NONE 0xFFFFFFFF
#endif

#if defined(_WIN32)
# undef EAFNOSUPPORT
# define EAFNOSUPPORT WSAEAFNOSUPPORT
# undef EWOULDBLOCK
# define EWOULDBLOCK WSAEWOULDBLOCK
# undef EAGAIN
# define EAGAIN WSAEWOULDBLOCK
#endif

#ifdef HAVE_LINUX_DCCP_H
/* TODO: use glibc instead of linux-kernel headers */
# include <linux/dccp.h>
# define SOL_DCCP 269
#endif

#include "libvlc.h" /* vlc_object_waitpipe */

extern int rootwrap_bind (int family, int socktype, int protocol,
                          const struct sockaddr *addr, size_t alen);

int net_Socket (vlc_object_t *p_this, int family, int socktype,
                int protocol)
{
    int fd = vlc_socket (family, socktype, protocol, true);
    if (fd == -1)
    {
        if (net_errno != EAFNOSUPPORT)
            msg_Err (p_this, "cannot create socket: %m");
        return -1;
    }

    setsockopt (fd, SOL_SOCKET, SO_REUSEADDR, &(int){ 1 }, sizeof (int));

#ifdef IPV6_V6ONLY
    /*
     * Accepts only IPv6 connections on IPv6 sockets.
     * If possible, we should open two sockets, but it is not always possible.
     */
    if (family == AF_INET6)
        setsockopt (fd, IPPROTO_IPV6, IPV6_V6ONLY, &(int){ 1 }, sizeof (int));
#endif

#if defined (_WIN32)
# ifndef IPV6_PROTECTION_LEVEL
#  warning Please update your C library headers.
#  define IPV6_PROTECTION_LEVEL 23
#  define PROTECTION_LEVEL_UNRESTRICTED 10
# endif
    if (family == AF_INET6)
        setsockopt (fd, IPPROTO_IPV6, IPV6_PROTECTION_LEVEL,
                    &(int){ PROTECTION_LEVEL_UNRESTRICTED }, sizeof (int));
#endif

#ifdef DCCP_SOCKOPT_SERVICE
    if (socktype == SOL_DCCP)
    {
        char *dccps = var_InheritString (p_this, "dccp-service");
        if (dccps != NULL)
        {
            setsockopt (fd, SOL_DCCP, DCCP_SOCKOPT_SERVICE, dccps,
                        (strlen (dccps) + 3) & ~3);
            free (dccps);
        }
    }
#endif

    return fd;
}


int *net_Listen (vlc_object_t *p_this, const char *psz_host,
                 int i_port, int type, int protocol)
{
    struct addrinfo hints = {
        .ai_socktype = type,
        .ai_protocol = protocol,
        .ai_flags = AI_PASSIVE | AI_NUMERICSERV | AI_IDN,
    }, *res;

    msg_Dbg (p_this, "net: listening to %s port %d",
             (psz_host != NULL) ? psz_host : "*", i_port);

    int i_val = vlc_getaddrinfo (psz_host, i_port, &hints, &res);
    if (i_val)
    {
        msg_Err (p_this, "Cannot resolve %s port %d : %s",
                 (psz_host != NULL) ? psz_host : "", i_port,
                 gai_strerror (i_val));
        return NULL;
    }

    int *sockv = NULL;
    unsigned sockc = 0;

    for (struct addrinfo *ptr = res; ptr != NULL; ptr = ptr->ai_next)
    {
        int fd = net_Socket (p_this, ptr->ai_family, ptr->ai_socktype,
                             ptr->ai_protocol);
        if (fd == -1)
        {
            msg_Dbg (p_this, "socket error: %m");
            continue;
        }

        /* Bind the socket */
#if defined (_WIN32)
        /*
         * Under Win32 and for multicasting, we bind to INADDR_ANY.
         * This is of course a severe bug, since the socket would logically
         * receive unicast traffic, and multicast traffic of groups subscribed
         * to via other sockets.
         */
        if (net_SockAddrIsMulticast (ptr->ai_addr, ptr->ai_addrlen)
         && (sizeof (struct sockaddr_storage) >= ptr->ai_addrlen))
        {
            // This works for IPv4 too - don't worry!
            struct sockaddr_in6 dumb =
            {
                .sin6_family = ptr->ai_addr->sa_family,
                .sin6_port =  ((struct sockaddr_in *)(ptr->ai_addr))->sin_port
            };

            bind (fd, (struct sockaddr *)&dumb, ptr->ai_addrlen);
        }
        else
#endif
        if (bind (fd, ptr->ai_addr, ptr->ai_addrlen))
        {
            net_Close (fd);
#if !defined(_WIN32)
            fd = rootwrap_bind (ptr->ai_family, ptr->ai_socktype,
                                ptr->ai_protocol,
                                ptr->ai_addr, ptr->ai_addrlen);
            if (fd != -1)
            {
                msg_Dbg (p_this, "got socket %d from rootwrap", fd);
            }
            else
#endif
            {
                msg_Err (p_this, "socket bind error (%m)");
                continue;
            }
        }

        if (net_SockAddrIsMulticast (ptr->ai_addr, ptr->ai_addrlen))
        {
            if (net_Subscribe (p_this, fd, ptr->ai_addr, ptr->ai_addrlen))
            {
                net_Close (fd);
                continue;
            }
        }

        /* Listen */
        switch (ptr->ai_socktype)
        {
            case SOCK_STREAM:
            case SOCK_RDM:
            case SOCK_SEQPACKET:
#ifdef SOCK_DCCP
            case SOCK_DCCP:
#endif
                if (listen (fd, INT_MAX))
                {
                    msg_Err (p_this, "socket listen error (%m)");
                    net_Close (fd);
                    continue;
                }
        }

        int *nsockv = (int *)realloc (sockv, (sockc + 2) * sizeof (int));
        if (nsockv != NULL)
        {
            nsockv[sockc++] = fd;
            sockv = nsockv;
        }
        else
            net_Close (fd);
    }

    freeaddrinfo (res);

    if (sockv != NULL)
        sockv[sockc] = -1;

    return sockv;
}

#undef net_Read
/*****************************************************************************
 * net_Read:
 *****************************************************************************
 * Reads from a network socket. Cancellation point.
 * If waitall is true, then we repeat until we have read the right amount of
 * data; in that case, a short count means EOF has been reached or the VLC
 * object has been signaled.
 *****************************************************************************/
ssize_t
net_Read (vlc_object_t *restrict p_this, int fd, const v_socket_t *vs,
          void *restrict p_buf, size_t i_buflen, bool waitall)
{
    struct pollfd ufd[2];

    ufd[0].fd = fd;
    ufd[0].events = POLLIN;
    ufd[1].fd = vlc_object_waitpipe (p_this);
    ufd[1].events = POLLIN;

    size_t i_total = 0;
    do
    {
        ssize_t n;
        if (vs != NULL)
        {
            int canc = vlc_savecancel ();
            n = vs->pf_recv (vs->p_sys, p_buf, i_buflen);
            vlc_restorecancel (canc);
        }
        else
        {
#ifdef _WIN32
            n = recv (fd, p_buf, i_buflen, 0);
#else
            n = read (fd, p_buf, i_buflen);
#endif
        }

        if (n < 0)
        {
            switch (net_errno)
            {
                case EAGAIN: /* no data */
#if (EAGAIN != EWOULDBLOCK)
                case EWOULDBLOCK:
#endif
                    break;
#ifndef _WIN32
                case EINTR:  /* asynchronous signal */
                    continue;
#else
                case WSAEMSGSIZE: /* datagram too big */
                    n = i_buflen;
                    break;
#endif
                default:
                    goto error;
            }
        }
        else
        if (n > 0)
        {
            i_total += n;
            p_buf = (char *)p_buf + n;
            i_buflen -= n;

            if (!waitall || i_buflen == 0)
                break;
        }
        else /* n == 0 */
            break;/* end of stream or empty packet */

        if (ufd[1].fd == -1)
        {
            errno = EINTR;
            return -1;
        }

        /* Wait for more data */
        if (poll (ufd, sizeof (ufd) / sizeof (ufd[0]), -1) < 0)
        {
            if (errno == EINTR)
                continue;
            goto error;
        }

        if (ufd[1].revents)
        {
            msg_Dbg (p_this, "socket %d polling interrupted", fd);
            errno = EINTR;
            return -1;
        }

        assert (ufd[0].revents);
    }
    while (i_buflen > 0);

    return i_total;
error:
    msg_Err (p_this, "read error: %m");
    return -1;
}

#undef net_Write
/**
 * Writes data to a file descriptor.
 * This blocks until all data is written or an error occurs.
 *
 * This function is a cancellation point if p_vs is NULL.
 * This function is not cancellation-safe if p_vs is not NULL.
 *
 * @return the total number of bytes written, or -1 if an error occurs
 * before any data is written.
 */
ssize_t net_Write( vlc_object_t *p_this, int fd, const v_socket_t *p_vs,
                   const void *restrict p_data, size_t i_data )
{
    size_t i_total = 0;
    struct pollfd ufd[2] = {
        { .fd = fd,                           .events = POLLOUT },
        { .fd = vlc_object_waitpipe (p_this), .events = POLLIN  },
    };

    if (unlikely(ufd[1].fd == -1))
    {
        vlc_testcancel ();
        return -1;
    }

    while( i_data > 0 )
    {
        ssize_t val;

        ufd[0].revents = ufd[1].revents = 0;

        if (poll (ufd, sizeof (ufd) / sizeof (ufd[0]), -1) == -1)
        {
            if (errno == EINTR)
                continue;
            msg_Err (p_this, "Polling error: %m");
            return -1;
        }

        if (i_total > 0)
        {   /* If POLLHUP resp. POLLERR|POLLNVAL occurs while we have already
             * read some data, it is important that we first return the number
             * of bytes read, and then return 0 resp. -1 on the NEXT call. */
            if (ufd[0].revents & (POLLHUP|POLLERR|POLLNVAL))
                break;
            if (ufd[1].revents) /* VLC object signaled */
                break;
        }
        else
        {
            if (ufd[1].revents)
            {
                errno = EINTR;
                goto error;
            }
        }

        if (p_vs != NULL)
            val = p_vs->pf_send (p_vs->p_sys, p_data, i_data);
        else
#ifdef _WIN32
            val = send (fd, p_data, i_data, 0);
#else
            val = write (fd, p_data, i_data);
#endif

        if (val == -1)
        {
            if (errno == EINTR)
                continue;
            msg_Err (p_this, "Write error: %m");
            break;
        }

        p_data = (const char *)p_data + val;
        i_data -= val;
        i_total += val;
    }

    if (unlikely(i_data == 0))
        vlc_testcancel (); /* corner case */

    if ((i_total > 0) || (i_data == 0))
        return i_total;

error:
    return -1;
}

#undef net_Gets
/**
 * Reads a line from a file descriptor.
 * This function is not thread-safe; the same file descriptor I/O cannot be
 * read by another thread at the same time (although it can be written to).
 *
 * @note This only works with stream-oriented file descriptors, not with
 * datagram or packet-oriented ones.
 *
 * @return nul-terminated heap-allocated string, or NULL on I/O error.
 */
char *net_Gets(vlc_object_t *obj, int fd, const v_socket_t *vs)
{
    char *buf = NULL;
    size_t bufsize = 0, buflen = 0;

    for (;;)
    {
        if (buflen == bufsize)
        {
            if (unlikely(bufsize >= (1 << 16)))
                goto error; /* put sane buffer size limit */

            char *newbuf = realloc(buf, bufsize + 1024);
            if (unlikely(newbuf == NULL))
                goto error;
            buf = newbuf;
            bufsize += 1024;
        }

        ssize_t val = net_Read(obj, fd, vs, buf + buflen, 1, false);
        if (val < 1)
            goto error;

        if (buf[buflen] == '\n')
            break;

        buflen++;
    }

    buf[buflen] = '\0';
    if (buflen > 0 && buf[buflen - 1] == '\r')
        buf[buflen - 1] = '\0';
    return buf;
error:
    free(buf);
    return NULL;
}

#undef net_Printf
ssize_t net_Printf( vlc_object_t *p_this, int fd, const v_socket_t *p_vs,
                    const char *psz_fmt, ... )
{
    int i_ret;
    va_list args;
    va_start( args, psz_fmt );
    i_ret = net_vaPrintf( p_this, fd, p_vs, psz_fmt, args );
    va_end( args );

    return i_ret;
}

#undef net_vaPrintf
ssize_t net_vaPrintf( vlc_object_t *p_this, int fd, const v_socket_t *p_vs,
                      const char *psz_fmt, va_list args )
{
    char    *psz;
    int      i_ret;

    int i_size = vasprintf( &psz, psz_fmt, args );
    if( i_size == -1 )
        return -1;
    i_ret = net_Write( p_this, fd, p_vs, psz, i_size ) < i_size
        ? -1 : i_size;
    free( psz );

    return i_ret;
}
