in.h

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/**
*

 * INET         An implementation of the TCP/IP protocol suite for the LINUX
 *              operating system.  INET is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              Definitions of the Internet Protocol.
 *
 * Version:     @(#)in.h        1.0.1   04/21/93
 *
 * Authors:     Original taken from the GNU Project <netinet/in.h> file.
 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *
 *              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.


*/
#ifndef _LINUX_IN_H
#define _LINUX_IN_H


/// Standard well-defined IP protocols.  
enum {
  IPPROTO_IP = 0,               ///< Dummy protocol for TCP             
  IPPROTO_ICMP = 1,             ///< Internet Control Message Protocol  
  IPPROTO_GGP = 2,              ///< Gateway Protocol (deprecated)      
  IPPROTO_TCP = 6,              ///< Transmission Control Protocol      
  IPPROTO_EGP = 8,              ///< Exterior Gateway Protocol          
  IPPROTO_PUP = 12,             ///< PUP protocol                               
  IPPROTO_UDP = 17,             ///< User Datagram Protocol             
  IPPROTO_IDP = 22,             ///< XNS IDP protocol                   

  IPPROTO_RAW = 255,            ///< Raw IP packets                     
  IPPROTO_MAX
};


/// Internet address. 
struct in_addr {
        unsigned long int       s_addr;
};


/// Structure describing an Internet (IP) socket address. 
#define __SOCK_SIZE__   16              ///< sizeof(struct sockaddr)    
struct sockaddr_in {
  short int             sin_family;     ///< Address family             
  unsigned short int    sin_port;       ///< Port number                        
  struct in_addr        sin_addr;       ///< Internet address           

  /// Pad to size of `struct sockaddr'. 
  unsigned char         __pad[__SOCK_SIZE__ - sizeof(short int) -
                        sizeof(unsigned short int) - sizeof(struct in_addr)];
};
#define sin_zero        __pad           ///< for BSD UNIX comp. -FvK    


/**
*

 * Definitions of the bits in an Internet address integer.
 * On subnets, host and network parts are found according
 * to the subnet mask, not these masks.


*/
#define IN_CLASSA(a)            ((((long int) (a)) & 0x80000000) == 0)
#define IN_CLASSA_NET           0xff000000
#define IN_CLASSA_NSHIFT        24
#define IN_CLASSA_HOST          (0xffffffff & ~IN_CLASSA_NET)
#define IN_CLASSA_MAX           128

#define IN_CLASSB(a)            ((((long int) (a)) & 0xc0000000) == 0x80000000)
#define IN_CLASSB_NET           0xffff0000
#define IN_CLASSB_NSHIFT        16
#define IN_CLASSB_HOST          (0xffffffff & ~IN_CLASSB_NET)
#define IN_CLASSB_MAX           65536

#define IN_CLASSC(a)            ((((long int) (a)) & 0xc0000000) == 0xc0000000)
#define IN_CLASSC_NET           0xffffff00
#define IN_CLASSC_NSHIFT        8
#define IN_CLASSC_HOST          (0xffffffff & ~IN_CLASSC_NET)

#define IN_CLASSD(a)            ((((long int) (a)) & 0xf0000000) == 0xe0000000)
#define IN_MULTICAST(a)         IN_CLASSD(a)

#define IN_EXPERIMENTAL(a)      ((((long int) (a)) & 0xe0000000) == 0xe0000000)
#define IN_BADCLASS(a)          ((((long int) (a)) & 0xf0000000) == 0xf0000000)

/// Address to accept any incoming messages. 
#define INADDR_ANY              ((unsigned long int) 0x00000000)

/// Address to send to all hosts. 
#define INADDR_BROADCAST        ((unsigned long int) 0xffffffff)

/// Address indicating an error return. 
#define INADDR_NONE             0xffffffff

/// Network number for local host loopback. 
#define IN_LOOPBACKNET          127

/// Address to loopback in software to local host.  
#define INADDR_LOOPBACK         0x7f000001      ///< 127.0.0.1          


/**
*

 * Options for use with `getsockopt' and `setsockopt' at
 * the IP level.  LINUX does not yet have the IP_OPTIONS
 * option (grin), so we undefine it for now.- HJ && FvK


*/
#if 0
# define IP_OPTIONS     1               ///< IP per-packet options      
#endif
#define IP_HDRINCL      2               ///< raw packet header option   


/// Linux Internet number representation function declarations. 
#undef ntohl
#undef ntohs
#undef htonl
#undef htons

extern unsigned long int        ntohl(unsigned long int);
extern unsigned short int       ntohs(unsigned short int);
extern unsigned long int        htonl(unsigned long int);
extern unsigned short int       htons(unsigned short int);

static __inline__ unsigned long int
__ntohl(unsigned long int x)
{
        __asm__("xchgb %b0,%h0\n\t"     ///< swap lower bytes   
                "rorl $16,%0\n\t"       ///< swap words         
                "xchgb %b0,%h0"         ///< swap higher bytes  
                :"=q" (x)
                : "0" (x));
        return x;
}

static __inline__ unsigned long int
__constant_ntohl(unsigned long int x)
{
        return (((x & 0x000000ff) << 24) |
                ((x & 0x0000ff00) <<  8) |
                ((x & 0x00ff0000) >>  8) |
                ((x & 0xff000000) >> 24));
}

static __inline__ unsigned short int
__ntohs(unsigned short int x)
{
        __asm__("xchgb %b0,%h0"         ///< swap bytes         
                : "=q" (x)
                :  "0" (x));
        return x;
}

static __inline__ unsigned short int
__constant_ntohs(unsigned short int x)
{
        return (((x & 0x00ff) << 8) |
                ((x & 0xff00) >> 8));
}

#define __htonl(x) __ntohl(x)
#define __htons(x) __ntohs(x)
#define __constant_htonl(x) __constant_ntohl(x)
#define __constant_htons(x) __constant_ntohs(x)

#ifdef  __OPTIMIZE__
#  define ntohl(x) \
(__builtin_constant_p((x)) ? \
 __constant_ntohl((x)) : \
 __ntohl((x)))
#  define ntohs(x) \
(__builtin_constant_p((x)) ? \
 __constant_ntohs((x)) : \
 __ntohs((x)))
#  define htonl(x) \
(__builtin_constant_p((x)) ? \
 __constant_htonl((x)) : \
 __htonl((x)))
#  define htons(x) \
(__builtin_constant_p((x)) ? \
 __constant_htons((x)) : \
 __htons((x)))
#endif

#endif  // _LINUX_IN_H 

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