#include	"u.h"
#include	"../port/lib.h"
#include	"mem.h"
#include	"dat.h"
#include	"fns.h"
#include	"../port/error.h"
#include	"kernel.h"
#include	"ip.h"

/*
 *  well known IP addresses
 */
uchar IPv4bcast[IPaddrlen] = {
	0, 0, 0, 0,
	0, 0, 0, 0,
	0, 0, 0xff, 0xff,
	0xff, 0xff, 0xff, 0xff
};
uchar IPv4allsys[IPaddrlen] = {
	0, 0, 0, 0,
	0, 0, 0, 0,
	0, 0, 0xff, 0xff,
	0xe0, 0, 0, 0x01
};
uchar IPv4allrouter[IPaddrlen] = {
	0, 0, 0, 0,
	0, 0, 0, 0,
	0, 0, 0xff, 0xff,
	0xe0, 0, 0, 0x02
};
uchar IPallbits[IPaddrlen] = {
	0xff, 0xff, 0xff, 0xff,
	0xff, 0xff, 0xff, 0xff,
	0xff, 0xff, 0xff, 0xff,
	0xff, 0xff, 0xff, 0xff
};
uchar IPnoaddr[IPaddrlen];

/*
 *  prefix of all v4 addresses
 */
uchar v4prefix[IPaddrlen] = {
	0, 0, 0, 0,
	0, 0, 0, 0,
	0, 0, 0xff, 0xff,
	0, 0, 0, 0
};


ushort
ptclcsum(Block *bp, int offset, int len)
{
	uchar *addr;
	ulong losum, hisum;
	ushort csum;
	int odd, blocklen, x;

	/* Correct to front of data area */
	while(bp != nil && offset && offset >= BLEN(bp)) {
		offset -= BLEN(bp);
		bp = bp->next;
	}
	if(bp == nil)
		return 0;

	addr = bp->rp + offset;
	blocklen = BLEN(bp) - offset;

	if(bp->next == nil) {
		if(blocklen < len)
			len = blocklen;
		return ~ptclbsum(addr, len) & 0xffff;
	}

	losum = 0;
	hisum = 0;

	odd = 0;
	while(len) {
		x = blocklen;
		if(len < x)
			x = len;

		csum = ptclbsum(addr, x);
		if(odd)
			hisum += csum;
		else
			losum += csum;
		odd = (odd+x) & 1;
		len -= x;

		bp = bp->next;
		if(bp == nil)
			break;
		blocklen = BLEN(bp);
		addr = bp->rp;
	}

	losum += hisum>>8;
	losum += (hisum&0xff)<<8;
	while((csum = losum>>16) != 0)
		losum = csum + (losum & 0xffff);

	return ~losum & 0xffff;
}

enum
{
	Isprefix= 16,
};

uchar prefixvals[256] =
{
[0x00] 0 | Isprefix,
[0x80] 1 | Isprefix,
[0xC0] 2 | Isprefix,
[0xE0] 3 | Isprefix,
[0xF0] 4 | Isprefix,
[0xF8] 5 | Isprefix,
[0xFC] 6 | Isprefix,
[0xFE] 7 | Isprefix,
[0xFF] 8 | Isprefix,
};

int
eipconv(va_list *arg, Fconv *f)
{
	char buf[8*5];
	static char *efmt = "%.2lux%.2lux%.2lux%.2lux%.2lux%.2lux";
	static char *ifmt = "%d.%d.%d.%d";
	uchar *p, ip[16];
	ulong *lp;
	ushort s;
	int i, j, n, eln, eli;

	switch(f->chr) {
	case 'E':		/* Ethernet address */
		p = va_arg(*arg, uchar*);
		sprint(buf, efmt, p[0], p[1], p[2], p[3], p[4], p[5]);
		break;
	case 'I':		/* Ip address */
		p = va_arg(*arg, uchar*);
common:
		if(memcmp(p, v4prefix, 12) == 0)
			sprint(buf, ifmt, p[12], p[13], p[14], p[15]);
		else {
			/* find longest elision */
			eln = eli = -1;
			for(i = 0; i < 16; i += 2){
				for(j = i; j < 16; j += 2)
					if(p[j] != 0 || p[j+1] != 0)
						break;
				if(j > i && j - i > eln){
					eli = i;
					eln = j - i;
				}
			}

			/* print with possible elision */
			n = 0;
			for(i = 0; i < 16; i += 2){
				if(i == eli){
					n += sprint(buf+n, "::");
					i += eln;
					if(i >= 16)
						break;
				} else if(i != 0)
					n += sprint(buf+n, ":");
				s = (p[i]<<8) + p[i+1];
				n += sprint(buf+n, "%ux", s);
			}
		}
		break;
	case 'i':		/* v6 address as 4 longs */
		lp = va_arg(*arg, ulong*);
		for(i = 0; i < 4; i++)
			hnputl(ip+4*i, *lp++);
		p = ip;
		goto common;
	case 'V':		/* v4 ip address */
		p = va_arg(*arg, uchar*);
		sprint(buf, ifmt, p[0], p[1], p[2], p[3]);
		break;
	case 'M':		/* ip mask */
		p = va_arg(*arg, uchar*);

		/* look for a prefix mask */
		for(i = 0; i < 16; i++)
			if(p[i] != 0xff)
				break;
		if(i < 16){
			if((prefixvals[p[i]] & Isprefix) == 0)
				goto common;
			for(j = i+1; j < 16; j++)
				if(p[j] != 0)
					goto common;
			n = 8*i + (prefixvals[p[i]] & ~Isprefix);
		} else
			n = 8*16;

		/* got one, use /xx format */
		sprint(buf, "/%d", n);
		break;
	default:
		strcpy(buf, "(eipconv)");
	}
	strconv(buf, f);
	return sizeof(uchar*);
}

#define CLASS(p) ((*(uchar*)(p))>>6)

extern char*
v4parseip(uchar *to, char *from)
{
	int i;
	char *p;

	p = from;
	for(i = 0; i < 4 && *p; i++){
		to[i] = strtoul(p, &p, 0);
		if(*p == '.')
			p++;
	}
	switch(CLASS(to)){
	case 0:	/* class A - 1 uchar net */
	case 1:
		if(i == 3){
			to[3] = to[2];
			to[2] = to[1];
			to[1] = 0;
		} else if (i == 2){
			to[3] = to[1];
			to[1] = 0;
		}
		break;
	case 2:	/* class B - 2 uchar net */
		if(i == 3){
			to[3] = to[2];
			to[2] = 0;
		}
		break;
	}
	return p;
}

int
isv4(uchar *ip)
{
	return memcmp(ip, v4prefix, IPv4off) == 0;
}

void
v4tov6(uchar *v6, uchar *v4)
{
	memmove(v6, v4prefix, IPv4off);
	memmove(v6 + IPv4off, v4, IPv4addrlen);
}

int
v6tov4(uchar *v4, uchar *v6)
{
	if(memcmp(v6, v4prefix, IPv4off) != 0)
		return -1;
	memmove(v4, v6 + IPv4off, IPv4addrlen);
	return 0;
}

ulong
parseip(uchar *to, char *from)
{
	int i, elipsis = 0, v4 = 1;
	ulong x;
	char *p, *op;

	memset(to, 0, IPaddrlen);
	p = from;
	for(i = 0; i < 16 && *p; i+=2){
		op = p;
		x = strtoul(p, &p, 16);
		if(*p == '.' || (*p == 0 && i == 0)){
			p = v4parseip(to+i, op);
			i += 4;
			break;
		} else {
			to[i] = x>>8;
			to[i+1] = x;
		}
		if(*p == ':'){
			v4 = 0;
			if(*++p == ':'){
				elipsis = i+2;
				p++;
			}
		}
	}
	if(i < 16){
		memmove(&to[elipsis+16-i], &to[elipsis], i-elipsis);
		memset(&to[elipsis], 0, 16-i);
	}
	if(v4){
		to[10] = to[11] = 0xff;
		return nhgetl(to+12);
	} else
		return 6;
}

/*
 *  hack to allow ip v4 masks to be entered in the old
 *  style
 */
ulong
parseipmask(uchar *to, char *from)
{
	ulong x;
	int i;
	uchar *p;

	if(*from == '/'){
		/* as a number of prefix bits */
		i = atoi(from+1);
		if(i < 0)
			i = 0;
		if(i > 128)
			i = 128;
		memset(to, 0, IPaddrlen);
		for(p = to; i >= 8; i -= 8)
			*p++ = 0xff;
		if(i > 0)
			*p = ~((1<<(8-i))-1);
		x = nhgetl(to+IPv4off);
	} else {
		/* as a straight bit mask */
		x = parseip(to, from);
		if(memcmp(to, v4prefix, IPv4off) == 0)
			memset(to, 0xff, IPv4off);
	}
	return x;
}

void
maskip(uchar *from, uchar *mask, uchar *to)
{
	int i;

	for(i = 0; i < IPaddrlen; i++)
		to[i] = from[i] & mask[i];
}

uchar classmask[4][16] = {
	0xff,0xff,0xff,0xff,  0xff,0xff,0xff,0xff,  0xff,0xff,0xff,0xff,  0xff,0x00,0x00,0x00,
	0xff,0xff,0xff,0xff,  0xff,0xff,0xff,0xff,  0xff,0xff,0xff,0xff,  0xff,0x00,0x00,0x00,
	0xff,0xff,0xff,0xff,  0xff,0xff,0xff,0xff,  0xff,0xff,0xff,0xff,  0xff,0xff,0x00,0x00,
	0xff,0xff,0xff,0xff,  0xff,0xff,0xff,0xff,  0xff,0xff,0xff,0xff,  0xff,0xff,0xff,0x00,
};

uchar*
defmask(uchar *ip)
{
	return classmask[ip[IPv4off]>>6];
}

/*
 *  parse a hex mac address
 */
int
parsemac(uchar *to, char *from, int len)
{
	char nip[4];
	char *p;
	int i;

	p = from;
	memset(to, 0, len);
	for(i = 0; i < len; i++){
		if(p[0] == '\0' || p[1] == '\0')
			break;

		nip[0] = p[0];
		nip[1] = p[1];
		nip[2] = '\0';
		p += 2;

		to[i] = strtoul(nip, 0, 16);
		if(*p == ':')
			p++;
	}
	return i;
}