head	1.2;access;symbols;locks	dls:1.2; strict;comment	@ * @;1.2date	97.09.21.19.30.32;	author dls;	state Dist;branches;next	1.1;1.1date	94.07.17.19.25.14;	author dls;	state Old;branches;next	;desc@@1.2log@pre-3e code@text@/* udpcksum.c - udpcksum */#include <conf.h>#include <kernel.h>#include <network.h>/*------------------------------------------------------------------------ *  udpcksum -  compute a UDP pseudo-header checksum *------------------------------------------------------------------------ */unsigned short udpcksum(pep, len)struct ep	*pep;int		len;{	struct	ip	*pip = (struct ip *)pep->ep_data;	struct	udp	*pudp = (struct udp *)pip->ip_data;	unsigned	short	*sptr;	unsigned	long ucksum;	int		i;	ucksum = 0;	sptr = (unsigned short *) &pip->ip_src;	/* 2*IP_ALEN octets = IP_ALEN shorts... */	/* they are in net order.		*/	for (i=0; i<IP_ALEN; ++i)		ucksum += *sptr++;	sptr = (unsigned short *)pudp;	ucksum += hs2net(IPT_UDP + len);	if (len % 2) {		((char *)pudp)[len] = 0;	/* pad */		len += 1;	/* for the following division */	}	len >>= 1;	/* convert to length in shorts */	for (i=0; i<len; ++i)		ucksum += *sptr++;	ucksum = (ucksum >> 16) + (ucksum & 0xffff);	ucksum += (ucksum >> 16);	return (short)(~ucksum & 0xffff);}@1.1log@Initial revision@text@a6 2#define	UDP_ALEN	IP_ALEN		/* length of src+dst, in shorts	*/d11 3a13 2unsigned short udpcksum(pip)struct	ip	*pip;d15 1d17 2a18 3	unsigned	short	*psh;	unsigned	long	sum;	short		len = net2hs(pudp->u_len);d21 1a21 5	sum = 0;	psh = (unsigned short *) pip->ip_src;	for (i=0; i<UDP_ALEN; ++i)		sum += *psh++;d23 8a30 3	psh = (unsigned short *)pudp;	sum += hs2net(pip->ip_proto + len);	if (len & 0x1) {d34 1a34 1	len /= 2;	/* convert to length in shorts */d37 3a39 3		sum += *psh++;	sum = (sum >> 16) + (sum & 0xffff);	sum += (sum >> 16);d41 1a41 1	return (short)(~sum & 0xffff);@