/* sock.c
 * - General Socket Functions
 *
 * Copyright (c) 1999 the icecast team
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <sys/types.h>
#include <ctype.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>

#ifndef _WIN32
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <netdb.h>
#include <sys/poll.h>
#else
#include <winsock2.h>
#define vsnprintf _vsnprintf
#define EINPROGRESS WSAEINPROGRESS
#define ENOTSOCK WSAENOTSOCK
#define EWOULDBLOCK WSAEWOULDBLOCK
#endif

#include "sock.h"
#include "resolver.h"

/* sock_initialize
**
** initializes the socket library.  you must call this
** before using the library!
*/
void sock_initialize(void)
{
#ifdef _WIN32
	WSADATA wsad;
	WSAStartup(0x0101, &wsad);
#endif

	resolver_initialize();
}

/* sock_shutdown
**
** shutdown the socket library.  remember to call this when you're
** through using the lib
*/
void sock_shutdown(void)
{
#ifdef _WIN32
	WSACleanup();
#endif
}

/* sock_get_localip
**
** gets the local ip address for the machine
** the ip it returns *should* be on the internet.
** in any case, it's as close as we can hope to get
** unless someone has better ideas on how to do this
*/
char *sock_get_localip(char *buff, int len)
{
	char temp[1024];

	if (gethostname(temp, 1024) != 0)
		return NULL;

	if (resolver_getip(temp, buff, len))
		return buff;

	return NULL;
}

/* sock_error
** 
** returns the last socket error
*/
int sock_error(void)
{
#ifdef _WIN32
	return WSAGetLastError();
#else
	return errno;
#endif
}

/* sock_recoverable
**
** determines if the socket error is recoverable
** in terms of non blocking sockets
*/
int sock_recoverable(int error)
{
    return (error == 0 || error == EAGAIN || error == EINTR || 
            error == EINPROGRESS || error == EWOULDBLOCK);
}

int sock_stalled (int error)
{
    return error == EAGAIN || error == EINPROGRESS || error == EWOULDBLOCK || 
        error == EALREADY;
}

int sock_success (int error)
{
    return error == 0;
}

int sock_connect_pending (int error)
{
    return error == EINPROGRESS || error == EALREADY;
}

/* sock_valid_socket
**
** determines if a sock_t represents a valid socket
*/
int sock_valid_socket(sock_t sock)
{
    int ret;
    int optval;
    socklen_t optlen;

    optlen = sizeof(int);
    ret = getsockopt(sock, SOL_SOCKET, SO_TYPE, &optval, &optlen);

    return (ret == 0);
}

/* inet_aton
**
** turns an ascii ip address into a binary representation
*/
#ifdef _WIN32
int inet_aton(const char *s, struct in_addr *a)
{
	int lsb, b2, b3, msb;

	if (sscanf(s, "%d.%d.%d.%d", &lsb, &b2, &b3, &msb) < 4) {
		return 0;
	}

	a->s_addr = inet_addr(s);
    
	return (a->s_addr != INADDR_NONE);
}
#endif /* _WIN32 */

/* sock_set_blocking
**
** set the sock blocking or nonblocking
** SOCK_BLOCK for blocking
** SOCK_NONBLOCK for nonblocking
*/
int sock_set_blocking(sock_t sock, const int block)
{
#ifdef _WIN32
	int varblock = block;
#endif

	if ((!sock_valid_socket(sock)) || (block < 0) || (block > 1))
		return SOCK_ERROR;

#ifdef _WIN32
	return ioctlsocket(sock, FIONBIO, &varblock);
#else
	return fcntl(sock, F_SETFL, (block == SOCK_BLOCK) ? 0 : O_NONBLOCK);
#endif
}

int sock_set_nolinger(sock_t sock)
{
	struct linger lin = { 0, 0 };
	return setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&lin, 
            sizeof(struct linger));
}

int sock_set_keepalive(sock_t sock)
{
	int keepalive = 1;
	return setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&keepalive, 
            sizeof(int));
}

/* sock_close
**
** close the socket
*/
int sock_close(sock_t sock)
{
#ifdef _WIN32
	return closesocket(sock);
#else
	return close(sock);
#endif
}

/* sock_writev
 *
 * write multiple buffers at once, return bytes actually written
 */
#ifdef HAVE_WRITEV

ssize_t sock_writev (int sock, const struct iovec *iov, const size_t count)
{
    return writev (sock, iov, count);
}

#else

ssize_t sock_writev (int sock, const struct iovec *iov, const size_t count)
{
    int i = count, accum = 0, ret;
    const struct iovec *v = iov;

    while (i)
    {
        if (v->iov_base && v->iov_len)
        {
            ret = sock_write_bytes (sock, v->iov_base, v->iov_len);
            if (ret == -1 && accum==0)
                return -1;
            if (ret == -1)
                ret = 0;
            accum += ret;
            if (ret < (int)v->iov_len)
                break;
        }
        v++;
        i--;
    }
    return accum;
}

#endif

/* sock_write_bytes
**
** write bytes to the socket
** this function will _NOT_ block
*/
int sock_write_bytes(sock_t sock, const void *buff, const size_t len)
{
	/* sanity check */
	if (!buff) {
		return SOCK_ERROR;
	} else if (len <= 0) {
		return SOCK_ERROR;
	} /*else if (!sock_valid_socket(sock)) {
		return SOCK_ERROR;
	} */

	return send(sock, buff, len, 0);
}

/* sock_write_string
**
** writes a string to a socket
** this function always blocks even if the socket is nonblocking
*/
int sock_write_string(sock_t sock, const char *buff)
{
	return (sock_write_bytes(sock, buff, strlen(buff)) > 0);
}

/* sock_write
**
** write a formatted string to the socket
** this function will always block, even if the socket is nonblocking
** will truncate the string if it's greater than 1024 chars.
*/
int sock_write(sock_t sock, const char *fmt, ...)
{
	char buff[1024];
	va_list ap;

	va_start(ap, fmt);
	vsnprintf(buff, 1024, fmt, ap);
	va_end(ap);
	
	return sock_write_bytes(sock, buff, strlen(buff));
}

int sock_read_bytes(sock_t sock, char *buff, const int len)
{

	/*if (!sock_valid_socket(sock)) return 0; */
	if (!buff) return 0;
	if (len <= 0) return 0;

	return recv(sock, buff, len, 0);
}

/* sock_read_line
**
** Read one line of at max len bytes from sock into buff.
** If ok, return 1 and nullterminate buff. Otherwize return 0.
** Terminating \n is not put into the buffer.
**
** this function will probably not work on sockets in nonblocking mode
*/
int sock_read_line(sock_t sock, char *buff, const int len)
{
	char c = '\0';
	int read_bytes, pos;
  
	/*if (!sock_valid_socket(sock)) {
		return 0;
	} else*/ if (!buff) {
		return 0;
	} else if (len <= 0) {
		return 0;
	}

	pos = 0;
	read_bytes = recv(sock, &c, 1, 0);

	if (read_bytes < 0) {
		return 0;
	}

	while ((c != '\n') && (pos < len) && (read_bytes == 1)) {
		if (c != '\r')
			buff[pos++] = c;
		read_bytes = recv(sock, &c, 1, 0);
	}
	
	if (read_bytes == 1) {
		buff[pos] = '\0';
		return 1;
	} else {
		return 0;
	}
}

/* see if a connection can be written to
** return -1 unable to check
** return 0 for not yet
** return 1 for ok 
*/
int sock_connected (int sock, unsigned timeout)
{
    fd_set wfds;
    int val = SOCK_ERROR;
    socklen_t size = sizeof val;
    struct timeval tv;

    tv.tv_sec = timeout;
    tv.tv_usec = 0;

    FD_ZERO(&wfds);
    FD_SET(sock, &wfds);

    switch (select(sock + 1, NULL, &wfds, NULL, &tv))
    {
        case 0:  return SOCK_TIMEOUT;
        default: if (getsockopt(sock, SOL_SOCKET, SO_ERROR, &val, &size) < 0)
                     val = SOCK_ERROR;
        case -1: return val;
    }
}

#ifdef HAVE_GETADDRINFO

int sock_connect_non_blocking (const char *hostname, const unsigned port)
{
    int sock = SOCK_ERROR;
    struct addrinfo *ai, *head, hints;
    char service[8];

    memset (&hints, 0, sizeof (hints));
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;

    snprintf (service, sizeof (service), "%u", port);

    if (getaddrinfo (hostname, service, &hints, &head))
        return SOCK_ERROR;

    ai = head;
    while (ai)
    {
        if ((sock = socket (ai->ai_family, ai->ai_socktype, ai->ai_protocol)) 
                > -1)
        {
            sock_set_blocking (sock, SOCK_NONBLOCK);
            if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 && 
                    !sock_connect_pending(sock_error()))
            {
                sock_close (sock);
                sock = SOCK_ERROR;
            }
            else
                break;
        }
        ai = ai->ai_next;
    }
    if (head) freeaddrinfo (head);
    
    return sock;
}


sock_t sock_connect_wto(const char *hostname, const int port, const int timeout)
{
    int sock = SOCK_ERROR;
    struct addrinfo *ai, *head, hints;
    char service[8];

    memset (&hints, 0, sizeof (hints));
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    snprintf (service, sizeof (service), "%u", port);

    if (getaddrinfo (hostname, service, &hints, &head))
        return SOCK_ERROR;

    ai = head;
    while (ai)
    {
        if ((sock = socket (ai->ai_family, ai->ai_socktype, ai->ai_protocol)) 
                > -1)
        {
            if (timeout)
            {
                sock_set_blocking (sock, SOCK_NONBLOCK);
                if (connect (sock, ai->ai_addr, ai->ai_addrlen) < 0)
                {
                    int ret = sock_connected (sock, timeout);
                    if (ret <= 0)
                    {
                        sock_close (sock);
                        sock = SOCK_ERROR;
                    }
                }
                sock_set_blocking(sock, SOCK_BLOCK);
            }
            else
            {
                if (connect (sock, ai->ai_addr, ai->ai_addrlen) < 0)
                {
                    sock_close (sock);
                    sock = SOCK_ERROR;
                }
            }
        }
        ai = ai->ai_next;
    }
    if (head) freeaddrinfo (head);

    return sock;
}

#else


int sock_try_connection (int sock, const char *hostname, const unsigned port)
{
    struct sockaddr_in sin, server;
    char ip[20];

    if (!hostname || !hostname[0] || port == 0)
        return -1;

    memset(&sin, 0, sizeof(struct sockaddr_in));
    memset(&server, 0, sizeof(struct sockaddr_in));

    if (!resolver_getip(hostname, ip, 20))
    {
        sock_close (sock);
        return -1;
    }

    if (inet_aton(ip, (struct in_addr *)&sin.sin_addr) == 0)
    {
        sock_close(sock);
        return -1;
    }

    memcpy(&server.sin_addr, &sin.sin_addr, sizeof(struct sockaddr_in));

    server.sin_family = AF_INET;
    server.sin_port = htons(port);

    return connect(sock, (struct sockaddr *)&server, sizeof(server));
}

int sock_connect_non_blocking (const char *hostname, const unsigned port)
{
    int sock;

    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock == -1)
        return -1;

    sock_set_blocking (sock, SOCK_NONBLOCK);
    sock_try_connection (sock, hostname, port);
    
    return sock;
}

sock_t sock_connect_wto(const char *hostname, const int port, const int timeout)
{
    int sock;

    sock = socket(AF_INET, SOCK_STREAM, 0);
    if (sock == -1)
        return -1;

    if (timeout)
    {
        sock_set_blocking (sock, SOCK_NONBLOCK);
        if (sock_try_connection (sock, hostname, port) < 0)
        {
            int ret = sock_connected (sock, timeout);
            if (ret <= 0)
            {
                sock_close (sock);
                return SOCK_ERROR;
            }
        }
        sock_set_blocking(sock, SOCK_BLOCK);
    }
    else
    {
        if (sock_try_connection (sock, hostname, port) < 0)
        {
            sock_close (sock);
            sock = SOCK_ERROR;
        }
    }
    return sock;
}
#endif


/* sock_get_server_socket
**
** create a socket for incoming requests on a specified port and
** interface.  if interface is null, listen on all interfaces.
** returns the socket, or SOCK_ERROR on failure
*/
sock_t sock_get_server_socket(const int port, char *sinterface)
{
#ifdef HAVE_IPV6
	struct sockaddr_storage sa;
#else	
	struct sockaddr_in sa;
#endif
	int sa_family, sa_len, error, opt;
	sock_t sock;
	char ip[40];

	if (port < 0)
		return SOCK_ERROR;

	/* defaults */
	memset(&sa, 0, sizeof(sa));
	sa_family = AF_INET;
	sa_len = sizeof(struct sockaddr_in);

	/* set the interface to bind to if specified */
	if (sinterface != NULL) {
		if (!resolver_getip(sinterface, ip, sizeof (ip)))
			return SOCK_ERROR;

#ifdef HAVE_IPV6
		if (inet_pton(AF_INET, ip, &((struct sockaddr_in*)&sa)->sin_addr) > 0) {
			((struct sockaddr_in*)&sa)->sin_family = AF_INET;
			((struct sockaddr_in*)&sa)->sin_port = htons(port);
		} else if (inet_pton(AF_INET6, ip, 
                    &((struct sockaddr_in6*)&sa)->sin6_addr) > 0) {
			sa_family = AF_INET6;
			sa_len = sizeof (struct sockaddr_in6);
			((struct sockaddr_in6*)&sa)->sin6_family = AF_INET6;
			((struct sockaddr_in6*)&sa)->sin6_port = htons(port);
		} else {
			return SOCK_ERROR;
		}
#else
		if (!inet_aton(ip, &sa.sin_addr)) {
			return SOCK_ERROR;
		} else {
			sa.sin_family = AF_INET;
			sa.sin_port = htons(port);
		}
#endif
	} else {
		((struct sockaddr_in*)&sa)->sin_addr.s_addr = INADDR_ANY;
		((struct sockaddr_in*)&sa)->sin_family = AF_INET;
		((struct sockaddr_in*)&sa)->sin_port = htons(port);
	}

	/* get a socket */
	sock = socket(sa_family, SOCK_STREAM, 0);
	if (sock == -1)
		return SOCK_ERROR;

	/* reuse it if we can */
	opt = 1;
	setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const void *)&opt, sizeof(int));
	
	/* bind socket to port */
	error = bind(sock, (struct sockaddr *)&sa, sa_len);
	if (error == -1)
		return SOCK_ERROR;

	return sock;
}

int sock_listen(sock_t serversock, int backlog)
{
	if (!sock_valid_socket(serversock))
		return 0;

	if (backlog <= 0)
		backlog = 10;

	return (listen(serversock, backlog) == 0);
}

int sock_accept(sock_t serversock, char *ip, int len)
{
	struct sockaddr_in sin;
	int ret;
	socklen_t slen;

	if (!sock_valid_socket(serversock))
		return SOCK_ERROR;

	slen = sizeof(struct sockaddr_in);
	ret = accept(serversock, (struct sockaddr *)&sin, &slen);

	if (ret >= 0 && ip != NULL) {
        // inet_ntoa is not reentrant, we should protect this
		strncpy(ip, inet_ntoa(sin.sin_addr), len);
		sock_set_nolinger(ret);
		sock_set_keepalive(ret);
	}

	return ret;
}