/*
 * Netbios is big endian (network byte order),
 * however SMB/CIFS is little endian (sigh)
 */
#include <u.h>
#include <libc.h>
#include <ip.h>
#include "nbcache.h"

Pkt *
allocpkt(int size)
{
	Pkt *p;

	p = mallocz(size+sizeof(Pkt), 1);
	p->size = size;
	p->buf = (uchar *)p + sizeof(Pkt);
	p->up = (Udphdr *)p->buf;
	p->pos = p->buf;
	p->end = p->buf + p->size;

	return p;
}

void
readpkt(int fd, Pkt *p)
{
	int n;
	
	if((n = read(fd, p->buf, p->size)) < 0)
		sysfatal("net read failed - %r\n");
	p->pos = p->buf + sizeof(Udphdr);
	p->end = p->buf + n;
}

void
w8(Pkt *p, int n)
{
	if(p->end - p->pos < 1){
		fprint(2, "w8() unexpected end of packet (%uld<%d)\n",
			p->end - p->pos, 1);
		longjmp(p->err, 1);
	}
	*p->pos++ = n;
}

int
r8(Pkt *p)
{
	int n;

	if(p->end - p->pos < 1){
		fprint(2, "r8() unexpected end of packet (%uld<%d)\n",
			p->end - p->pos, 1);
		longjmp(p->err, 1);
	}
	n = *p->pos++;
	return n;
}

int
rl16(Pkt *p)
{
	int n;

	if(p->end - p->pos < 2){
		fprint(2, "r16() unexpected end of packet (%uld<%d)\n",
			p->end - p->pos, 2);
		longjmp(p->err, 1);
	}
	n = *p->pos++;
	n |= (*p->pos++) << 8;
	return n;
}

void
wl16(Pkt *p, int n)
{
	if(p->end - p->pos < 2){
		fprint(2, "wl16() unexpected end of packet (%uld<%d)\n",
			p->end - p->pos, 2);
		longjmp(p->err, 1);
	}
	*p->pos++ = n;
	*p->pos++ = n >> 8;
}

int
rb16(Pkt *p)
{
	int n;

	if(p->end - p->pos < 2){
		fprint(2, "rb16() unexpected end of packet (%uld<%d)\n",
			p->end - p->pos, 2);
		longjmp(p->err, 1);
	}
	n = (*p->pos++) << 8;
	n |= *p->pos++;
	return n;
}

void
wb16(Pkt *p, int n)
{
	if(p->end - p->pos < 2){
		fprint(2, "wb16() unexpected end of packet (%uld<%d)\n",
			p->end - p->pos, 2);
		longjmp(p->err, 1);
	}
	*p->pos++ = n >> 8;
	*p->pos++ = n;
}

int
rl32(Pkt *p)
{
	int n;

	if(p->end - p->pos < 4){
		fprint(2, "rl32() unexpected end of packet (%uld<%d)\n",
			p->end - p->pos, 4);
		longjmp(p->err, 1);
	}
	n = *p->pos++;
	n |= (*p->pos++) << 8;
	n |= (*p->pos++) << 16;
	n |= (*p->pos++) << 24;
	return n;
}

void
wl32(Pkt *p, int n)
{
	if(p->end - p->pos < 4){
		fprint(2, "wl32() unexpected end of packet (%uld<%d)\n",
			p->end - p->pos, 4);
		longjmp(p->err, 1);
	}
	*p->pos++ = n;
	*p->pos++ = n >> 8;
	*p->pos++ = n >> 16;
	*p->pos++ = n >> 24;
}

int
rb32(Pkt *p)
{
	int n;

	if(p->end - p->pos < 4){
		fprint(2, "rb32() unexpected end of packet (%uld<%d)\n",
			p->end - p->pos, 4);
		longjmp(p->err, 1);
	}
	n = (*p->pos++) << 24;
	n |= (*p->pos++) << 16;
	n |= (*p->pos++) << 8;
	n |= *p->pos++;
	return n;
}

void
wb32(Pkt *p, int n)
{
	if(p->end - p->pos < 4){
		fprint(2, "rb32() unexpected end of packet (%uld<%d)\n",
			p->end - p->pos, 4);
		longjmp(p->err, 1);
	}
	*p->pos++ = n >> 24;
	*p->pos++ = n >> 16;
	*p->pos++ = n >> 8;
	*p->pos++ = n;
}

void
skip(Pkt *p, int len)
{
	if(p->end - p->pos < len){
		fprint(2, "skip() unexpected end of packet (%uld<%d)\n",
			p->end - p->pos, len);
		longjmp(p->err, 1);
	}
	p->pos += len;
}

void
rmem(Pkt *p, void *buf, int len)
{
	if(p->end - p->pos < len){
		fprint(2, "rmem() unexpected end of packet (%uld<%d)\n",
			p->end - p->pos, len);
		longjmp(p->err, 1);
	}
	memcpy(buf, p->pos, len);
	p->pos += len;
}

void
wmem(Pkt *p, void *buf, int len)
{
	if(p->end - p->pos < len){
		fprint(2, "wmem() unexpected end of packet (%uld<%d)\n",
			p->end - p->pos, len);
		longjmp(p->err, 1);
	}
	memcpy(p->pos, buf, len);
	p->pos += len;
}

void
rstr(Pkt *p, char *buf, int len)
{
	int i;

	if(p->end - p->pos < 1){
		fprint(2, "rstr() unexpected end of packet (%uld<%d)\n",
			p->end - p->pos, 1);
		longjmp(p->err, 1);
	}
	for(i = 0; i < len; i++)
		if((buf[i] = r8(p)) == 0)
			break;
	buf[len-1] = 0;
}

void
wstr(Pkt *p, char *buf)
{

	while(*buf)
		w8(p, *buf++);
	w8(p, 0);
}

int
rnbname(Pkt *p, char *buf, int len)
{
	int i, type;

	type = *p->pos++;
	for(i = 0; i < len && p->end - p->pos > 3; i++){
		buf[i] = ((*p->pos++ - 'A') << 4) & 0xff;
		buf[i] |= *p->pos++ - 'A';
		if(*p->pos == 0){
			p->pos++;
			i++;
			break;
		}
	}
	buf[i] = 0;
	return type;
}

void
pnbname(Pkt *p, char *name, char type, char pad)
{
	char c;
	int i;
	int done = 0;

	*(p->pos++) = 0x20;
	for(i = 0; i < 15; i++) {
		if(!done && name[i] == '\0')
			done = 1;
		if(done)
			c = pad;
		else
			c = toupper(name[i]);
		*(p->pos++) = (c >> 4) + 'A';
		*(p->pos++) = (c & 0xf) + 'A';
	}
	*(p->pos++) = (type >> 4) + 'A';
	*(p->pos++) = (type & 0xf) + 'A';
	*(p->pos++) = 0x0;
}