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/*
* Creation Date: <2000/12/01 01:26:38 samuel>
* Time-stamp: <2000/12/10 21:10:58 samuel>
*
* <ip.h>
*
* Handles the TCP and UDP protocol
*
* Copyright (C) 2000 Samuel Rydh (samuel@ibrium.se)
*
* 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
*
*/
#ifndef _H_IP
#define _H_IP
/* defined in ip.c */
extern void ip_init( void );
extern void ip_cleanup( void );
extern int tx_packet_hook( char *ethpacket, int size, void *enetif );
extern int rx_packet_hook( char *ethpacket, int size, void *enetif );
/* defined in osi_enet.c */
extern int synthesize_eth_packet( char *ethpacket, int size, void *iface );
/* The kernel arp header does not include the ethernet specific fields */
struct eth_arphdr {
unsigned short ar_hrd; /* format of hardware address */
unsigned short ar_pro; /* format of protocol address */
unsigned char ar_hln; /* length of hardware address */
unsigned char ar_pln; /* length of protocol address */
unsigned short ar_op; /* ARP opcode (command) */
/* ethernet specific fields */
unsigned char ar_sha[6]; /* sender hardware address */
unsigned char ar_sip[4]; /* sender IP address */
unsigned char ar_tha[6]; /* target hardware address */
unsigned char ar_tip[4]; /* target IP address */
};
/************************************************************************/
/* TCP Checksum (definitions from checksum.S) */
/************************************************************************/
/*
* computes the checksum of a memory block at buff, length len,
* and adds in "sum" (32-bit)
*
* returns a 32-bit number suitable for feeding into itself
* or csum_tcpudp_magic
*
* this function must be called with even lengths, except
* for the last fragment, which may be odd
*
* it's best to have buff aligned on a 32-bit boundary
*/
extern unsigned int csum_partial(const unsigned char * buff, int len,
unsigned int sum);
/*
* turns a 32-bit partial checksum (e.g. from csum_partial) into a
* 1's complement 16-bit checksum.
*/
static inline unsigned int csum_fold(unsigned int sum)
{
unsigned int tmp;
/* swap the two 16-bit halves of sum */
__asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
/* if there is a carry from adding the two 16-bit halves,
it will carry from the lower half into the upper half,
giving us the correct sum in the upper half. */
sum = ~(sum + tmp) >> 16;
return sum;
}
/*
* this routine is used for miscellaneous IP-like checksums, mainly
* in icmp.c
*/
static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
{
return csum_fold(csum_partial(buff, len, 0));
}
/*
* FIXME: I swiped this one from the sparc and made minor modifications.
* It may not be correct. -- Cort
*/
static inline ulong csum_tcpudp_nofold( ulong saddr, ulong daddr, unsigned short len,
unsigned short proto, unsigned int sum )
{
__asm__("
addc %0,%0,%1
adde %0,%0,%2
adde %0,%0,%3
addze %0,%0
"
: "=r" (sum)
: "r" (daddr), "r"(saddr), "r"((proto<<16)+len), "0"(sum));
return sum;
}
/*
* This is a version of ip_compute_csum() optimized for IP headers,
* which always checksum on 4 octet boundaries. ihl is the number
* of 32-bit words and is always >= 5.
*/
extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl);
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 16-bit checksum, already complemented
*/
extern unsigned short csum_tcpudp_magic(ulong saddr, ulong daddr, unsigned short len,
unsigned short proto, unsigned int sum);
/*
* Computes the checksum of a memory block at src, length len,
* and adds in "sum" (32-bit), while copying the block to dst.
*/
extern unsigned int csum_partial_copy_generic(const char *src, char *dst,
int len, unsigned int sum );
#endif /* _H_IP */
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