SDL_net.h

/*
  SDL_net:  An example cross-platform network library for use with SDL
  Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>
  Copyright (C) 2012 Simeon Maxein <smaxein@googlemail.com>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

#ifndef SDL_NET_H_
#define SDL_NET_H_

#ifdef WITHOUT_SDL
#include <stdint.h>
typedef uint8_t Uint8;
typedef uint16_t Uint16;
typedef uint32_t Uint32;

typedef struct SDLNet_version {
    Uint8 major;
    Uint8 minor;
    Uint8 patch;
} SDLNet_version;

#else /* WITHOUT_SDL */

#include "SDL.h"
#include "SDL_endian.h"
#include "SDL_version.h"

typedef SDL_version SDLNet_version;

#endif /* WITHOUT_SDL */

#include "begin_code.h"

/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
extern "C" {
#endif

/* Printable format: "%d.%d.%d", MAJOR, MINOR, PATCHLEVEL
*/
#define SDL_NET_MAJOR_VERSION   2
#define SDL_NET_MINOR_VERSION   0
#define SDL_NET_PATCHLEVEL      1

/* This macro can be used to fill a version structure with the compile-time
 * version of the SDL_net library.
 */
#define SDL_NET_VERSION(X)                          \
{                                                   \
    (X)->major = SDL_NET_MAJOR_VERSION;             \
    (X)->minor = SDL_NET_MINOR_VERSION;             \
    (X)->patch = SDL_NET_PATCHLEVEL;                \
}

/**
 *  This is the version number macro for the current SDL_net version.
 */
#define SDL_NET_COMPILEDVERSION \
    SDL_VERSIONNUM(SDL_NET_MAJOR_VERSION, SDL_NET_MINOR_VERSION, SDL_NET_PATCHLEVEL)

/**
 *  This macro will evaluate to true if compiled with SDL_net at least X.Y.Z.
 */
#define SDL_NET_VERSION_ATLEAST(X, Y, Z) \
    (SDL_NET_COMPILEDVERSION >= SDL_VERSIONNUM(X, Y, Z))

/* This function gets the version of the dynamically linked SDL_net library.
   it should NOT be used to fill a version structure, instead you should
   use the SDL_NET_VERSION() macro.
 */
extern DECLSPEC const SDLNet_version * SDLCALL SDLNet_Linked_Version(void);

/* Initialize/Cleanup the network API
   SDL must be initialized before calls to functions in this library,
   because this library uses utility functions from the SDL library.
*/
extern DECLSPEC int  SDLCALL SDLNet_Init(void);
extern DECLSPEC void SDLCALL SDLNet_Quit(void);

/***********************************************************************/
/* IPv4 hostname resolution API                                        */
/***********************************************************************/

typedef struct {
    Uint32 host;            /* 32-bit IPv4 host address */
    Uint16 port;            /* 16-bit protocol port */
} IPaddress;

/* Resolve a host name and port to an IP address in network form.
   If the function succeeds, it will return 0.
   If the host couldn't be resolved, the host portion of the returned
   address will be INADDR_NONE, and the function will return -1.
   If 'host' is NULL, the resolved host will be set to INADDR_ANY.
 */
#ifndef INADDR_ANY
#define INADDR_ANY      0x00000000
#endif
#ifndef INADDR_NONE
#define INADDR_NONE     0xFFFFFFFF
#endif
#ifndef INADDR_LOOPBACK
#define INADDR_LOOPBACK     0x7f000001
#endif
#ifndef INADDR_BROADCAST
#define INADDR_BROADCAST    0xFFFFFFFF
#endif
extern DECLSPEC int SDLCALL SDLNet_ResolveHost(IPaddress *address, const char *host, Uint16 port);

/* Resolve an ip address to a host name in canonical form.
   If the ip couldn't be resolved, this function returns NULL,
   otherwise a pointer to a static buffer containing the hostname
   is returned.  Note that this function is not thread-safe.
*/
extern DECLSPEC const char * SDLCALL SDLNet_ResolveIP(const IPaddress *ip);

/* Get the addresses of network interfaces on this system.
   This returns the number of addresses saved in 'addresses'
 */
extern DECLSPEC int SDLCALL SDLNet_GetLocalAddresses(IPaddress *addresses, int maxcount);

/***********************************************************************/
/* TCP network API                                                     */
/***********************************************************************/

typedef struct _TCPsocket *TCPsocket;

/* Open a TCP network socket
   If ip.host is INADDR_NONE or INADDR_ANY, this creates a local server
   socket on the given port, otherwise a TCP connection to the remote
   host and port is attempted. The address passed in should already be
   swapped to network byte order (addresses returned from
   SDLNet_ResolveHost() are already in the correct form).
   The newly created socket is returned, or NULL if there was an error.
*/
extern DECLSPEC TCPsocket SDLCALL SDLNet_TCP_Open(IPaddress *ip);

/* Accept an incoming connection on the given server socket.
   The newly created socket is returned, or NULL if there was an error.
*/
extern DECLSPEC TCPsocket SDLCALL SDLNet_TCP_Accept(TCPsocket server);

/* Get the IP address of the remote system associated with the socket.
   If the socket is a server socket, this function returns NULL.
*/
extern DECLSPEC IPaddress * SDLCALL SDLNet_TCP_GetPeerAddress(TCPsocket sock);

/* Send 'len' bytes of 'data' over the non-server socket 'sock'
   This function returns the actual amount of data sent.  If the return value
   is less than the amount of data sent, then either the remote connection was
   closed, or an unknown socket error occurred.
*/
extern DECLSPEC int SDLCALL SDLNet_TCP_Send(TCPsocket sock, const void *data,
        int len);

/* Receive up to 'maxlen' bytes of data over the non-server socket 'sock',
   and store them in the buffer pointed to by 'data'.
   This function returns the actual amount of data received.  If the return
   value is less than or equal to zero, then either the remote connection was
   closed, or an unknown socket error occurred.
*/
extern DECLSPEC int SDLCALL SDLNet_TCP_Recv(TCPsocket sock, void *data, int maxlen);

/* Close a TCP network socket */
extern DECLSPEC void SDLCALL SDLNet_TCP_Close(TCPsocket sock);


/***********************************************************************/
/* UDP network API                                                     */
/***********************************************************************/

/* The maximum channels on a a UDP socket */
#define SDLNET_MAX_UDPCHANNELS  32
/* The maximum addresses bound to a single UDP socket channel */
#define SDLNET_MAX_UDPADDRESSES 4

typedef struct _UDPsocket *UDPsocket;
typedef struct {
    int channel;        /* The src/dst channel of the packet */
    Uint8 *data;        /* The packet data */
    int len;            /* The length of the packet data */
    int maxlen;         /* The size of the data buffer */
    int status;         /* packet status after sending */
    IPaddress address;  /* The source/dest address of an incoming/outgoing packet */
} UDPpacket;

/* Allocate/resize/free a single UDP packet 'size' bytes long.
   The new packet is returned, or NULL if the function ran out of memory.
 */
extern DECLSPEC UDPpacket * SDLCALL SDLNet_AllocPacket(int size);
extern DECLSPEC int SDLCALL SDLNet_ResizePacket(UDPpacket *packet, int newsize);
extern DECLSPEC void SDLCALL SDLNet_FreePacket(UDPpacket *packet);

/* Allocate/Free a UDP packet vector (array of packets) of 'howmany' packets,
   each 'size' bytes long.
   A pointer to the first packet in the array is returned, or NULL if the
   function ran out of memory.
 */
extern DECLSPEC UDPpacket ** SDLCALL SDLNet_AllocPacketV(int howmany, int size);
extern DECLSPEC void SDLCALL SDLNet_FreePacketV(UDPpacket **packetV);


/* Open a UDP network socket
   If 'port' is non-zero, the UDP socket is bound to a local port.
   The 'port' should be given in native byte order, but is used
   internally in network (big endian) byte order, in addresses, etc.
   This allows other systems to send to this socket via a known port.
*/
extern DECLSPEC UDPsocket SDLCALL SDLNet_UDP_Open(Uint16 port);

/* Set the percentage of simulated packet loss for packets sent on the socket.
*/
extern DECLSPEC void SDLCALL SDLNet_UDP_SetPacketLoss(UDPsocket sock, int percent);

/* Bind the address 'address' to the requested channel on the UDP socket.
   If the channel is -1, then the first unbound channel that has not yet
   been bound to the maximum number of addresses will be bound with
   the given address as it's primary address.
   If the channel is already bound, this new address will be added to the
   list of valid source addresses for packets arriving on the channel.
   If the channel is not already bound, then the address becomes the primary
   address, to which all outbound packets on the channel are sent.
   This function returns the channel which was bound, or -1 on error.
*/
extern DECLSPEC int SDLCALL SDLNet_UDP_Bind(UDPsocket sock, int channel, const IPaddress *address);

/* Unbind all addresses from the given channel */
extern DECLSPEC void SDLCALL SDLNet_UDP_Unbind(UDPsocket sock, int channel);

/* Get the primary IP address of the remote system associated with the
   socket and channel.  If the channel is -1, then the primary IP port
   of the UDP socket is returned -- this is only meaningful for sockets
   opened with a specific port.
   If the channel is not bound and not -1, this function returns NULL.
 */
extern DECLSPEC IPaddress * SDLCALL SDLNet_UDP_GetPeerAddress(UDPsocket sock, int channel);

/* Send a vector of packets to the the channels specified within the packet.
   If the channel specified in the packet is -1, the packet will be sent to
   the address in the 'src' member of the packet.
   Each packet will be updated with the status of the packet after it has
   been sent, -1 if the packet send failed.
   This function returns the number of packets sent.
*/
extern DECLSPEC int SDLCALL SDLNet_UDP_SendV(UDPsocket sock, UDPpacket **packets, int npackets);

/* Send a single packet to the specified channel.
   If the channel specified in the packet is -1, the packet will be sent to
   the address in the 'src' member of the packet.
   The packet will be updated with the status of the packet after it has
   been sent.
   This function returns 1 if the packet was sent, or 0 on error.

   NOTE:
   The maximum size of the packet is limited by the MTU (Maximum Transfer Unit)
   of the transport medium.  It can be as low as 250 bytes for some PPP links,
   and as high as 1500 bytes for ethernet.
*/
extern DECLSPEC int SDLCALL SDLNet_UDP_Send(UDPsocket sock, int channel, UDPpacket *packet);

/* Receive a vector of pending packets from the UDP socket.
   The returned packets contain the source address and the channel they arrived
   on.  If they did not arrive on a bound channel, the the channel will be set
   to -1.
   The channels are checked in highest to lowest order, so if an address is
   bound to multiple channels, the highest channel with the source address
   bound will be returned.
   This function returns the number of packets read from the network, or -1
   on error.  This function does not block, so can return 0 packets pending.
*/
extern DECLSPEC int SDLCALL SDLNet_UDP_RecvV(UDPsocket sock, UDPpacket **packets);

/* Receive a single packet from the UDP socket.
   The returned packet contains the source address and the channel it arrived
   on.  If it did not arrive on a bound channel, the the channel will be set
   to -1.
   The channels are checked in highest to lowest order, so if an address is
   bound to multiple channels, the highest channel with the source address
   bound will be returned.
   This function returns the number of packets read from the network, or -1
   on error.  This function does not block, so can return 0 packets pending.
*/
extern DECLSPEC int SDLCALL SDLNet_UDP_Recv(UDPsocket sock, UDPpacket *packet);

/* Close a UDP network socket */
extern DECLSPEC void SDLCALL SDLNet_UDP_Close(UDPsocket sock);


/***********************************************************************/
/* Hooks for checking sockets for available data                       */
/***********************************************************************/

typedef struct _SDLNet_SocketSet *SDLNet_SocketSet;

/* Any network socket can be safely cast to this socket type */
typedef struct _SDLNet_GenericSocket {
    int ready;
} *SDLNet_GenericSocket;

/* Allocate a socket set for use with SDLNet_CheckSockets()
   This returns a socket set for up to 'maxsockets' sockets, or NULL if
   the function ran out of memory.
 */
extern DECLSPEC SDLNet_SocketSet SDLCALL SDLNet_AllocSocketSet(int maxsockets);

/* Add a socket to a set of sockets to be checked for available data */
extern DECLSPEC int SDLCALL SDLNet_AddSocket(SDLNet_SocketSet set, SDLNet_GenericSocket sock);
SDL_FORCE_INLINE int SDLNet_TCP_AddSocket(SDLNet_SocketSet set, TCPsocket sock)
{
    return SDLNet_AddSocket(set, (SDLNet_GenericSocket)sock);
}
SDL_FORCE_INLINE int SDLNet_UDP_AddSocket(SDLNet_SocketSet set, UDPsocket sock)
{
    return SDLNet_AddSocket(set, (SDLNet_GenericSocket)sock);
}


/* Remove a socket from a set of sockets to be checked for available data */
extern DECLSPEC int SDLCALL SDLNet_DelSocket(SDLNet_SocketSet set, SDLNet_GenericSocket sock);
SDL_FORCE_INLINE int SDLNet_TCP_DelSocket(SDLNet_SocketSet set, TCPsocket sock)
{
    return SDLNet_DelSocket(set, (SDLNet_GenericSocket)sock);
}
SDL_FORCE_INLINE int SDLNet_UDP_DelSocket(SDLNet_SocketSet set, UDPsocket sock)
{
    return SDLNet_DelSocket(set, (SDLNet_GenericSocket)sock);
}

/* This function checks to see if data is available for reading on the
   given set of sockets.  If 'timeout' is 0, it performs a quick poll,
   otherwise the function returns when either data is available for
   reading, or the timeout in milliseconds has elapsed, which ever occurs
   first.  This function returns the number of sockets ready for reading,
   or -1 if there was an error with the select() system call.
*/
extern DECLSPEC int SDLCALL SDLNet_CheckSockets(SDLNet_SocketSet set, Uint32 timeout);

/* After calling SDLNet_CheckSockets(), you can use this function on a
   socket that was in the socket set, to find out if data is available
   for reading.
*/
#define SDLNet_SocketReady(sock) _SDLNet_SocketReady((SDLNet_GenericSocket)(sock))
SDL_FORCE_INLINE int _SDLNet_SocketReady(SDLNet_GenericSocket sock)
{
    return (sock != NULL) && (sock->ready);
}

/* Free a set of sockets allocated by SDL_NetAllocSocketSet() */
extern DECLSPEC void SDLCALL SDLNet_FreeSocketSet(SDLNet_SocketSet set);

/***********************************************************************/
/* Error reporting functions                                           */
/***********************************************************************/

extern DECLSPEC void SDLCALL SDLNet_SetError(const char *fmt, ...);
extern DECLSPEC const char * SDLCALL SDLNet_GetError(void);

/***********************************************************************/
/* Inline functions to read/write network data                         */
/***********************************************************************/

/* Warning, some systems have data access alignment restrictions */
#if defined(sparc) || defined(mips) || defined(__arm__)
#define SDL_DATA_ALIGNED    1
#endif
#ifndef SDL_DATA_ALIGNED
#define SDL_DATA_ALIGNED    0
#endif

/* Write a 16/32-bit value to network packet buffer */
#define SDLNet_Write16(value, areap) _SDLNet_Write16(value, areap)
#define SDLNet_Write32(value, areap) _SDLNet_Write32(value, areap)

/* Read a 16/32-bit value from network packet buffer */
#define SDLNet_Read16(areap) _SDLNet_Read16(areap)
#define SDLNet_Read32(areap) _SDLNet_Read32(areap)

#if !defined(WITHOUT_SDL) && !SDL_DATA_ALIGNED

SDL_FORCE_INLINE void _SDLNet_Write16(Uint16 value, void *areap)
{
    *(Uint16 *)areap = SDL_SwapBE16(value);
}

SDL_FORCE_INLINE void _SDLNet_Write32(Uint32 value, void *areap)
{
    *(Uint32 *)areap = SDL_SwapBE32(value);
}

SDL_FORCE_INLINE Uint16 _SDLNet_Read16(const void *areap)
{
    return SDL_SwapBE16(*(const Uint16 *)areap);
}

SDL_FORCE_INLINE Uint32 _SDLNet_Read32(const void *areap)
{
    return SDL_SwapBE32(*(const Uint32 *)areap);
}

#else /* !defined(WITHOUT_SDL) && !SDL_DATA_ALIGNED */

SDL_FORCE_INLINE void _SDLNet_Write16(Uint16 value, void *areap)
{
    Uint8 *area = (Uint8*)areap;
    area[0] = (value >>  8) & 0xFF;
    area[1] =  value        & 0xFF;
}

SDL_FORCE_INLINE void _SDLNet_Write32(Uint32 value, void *areap)
{
    Uint8 *area = (Uint8*)areap;
    area[0] = (value >> 24) & 0xFF;
    area[1] = (value >> 16) & 0xFF;
    area[2] = (value >>  8) & 0xFF;
    area[3] =  value        & 0xFF;
}

SDL_FORCE_INLINE Uint16 _SDLNet_Read16(void *areap)
{
    Uint8 *area = (Uint8*)areap;
    return ((Uint16)area[0]) << 8 | ((Uint16)area[1]);
}

SDL_FORCE_INLINE Uint32 _SDLNet_Read32(const void *areap)
{
    const Uint8 *area = (const Uint8*)areap;
    return ((Uint32)area[0]) << 24 | ((Uint32)area[1]) << 16 | ((Uint32)area[2]) << 8 | ((Uint32)area[3]);
}

#endif /* !defined(WITHOUT_SDL) && !SDL_DATA_ALIGNED */

/* Ends C function definitions when using C++ */
#ifdef __cplusplus
}
#endif
#include "close_code.h"

#endif /* SDL_NET_H_ */