asn1.c

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/*
 * asn1.c
 *
 * Copyright (c) 2000 Dug Song <dugsong@monkey.org>
 *
 * $Id: asn1.c,v 1.4 2001/03/15 08:32:58 dugsong Exp $
 */
 
#include "config.h"
 
#include <sys/types.h>
#include <arpa/nameser.h>
 
#include <unistd.h>
 
#include "buf.h"
#include "asn1.h"
 
int
asn1_type(buf_t buf)
{
    u_char c;
 
    if (buf_get(buf, &c, 1) != 1)
        return (-1);
 
    return (c & 0x1f);
}
 
int
asn1_len(buf_t buf)
{
    u_char *p, c;
    int num;
 
    if (buf_get(buf, &c, 1) != 1)
        return (-1);
 
    if (c >= 128) {
        c &= ~128;
        p = buf_ptr(buf);
        
        if (buf_skip(buf, c) < 0)
            return (-1);
 
        switch (c) {
        case 1:
            num = *p;
            break;
        case 2:
            GETSHORT(num, p);
            break;
        case 3:
            p--; GETLONG(num, p);
            num &= 0xfff;
            break;
        case 4:
            GETLONG(num, p);
            break;
        default:
            return (-1);
        }
    }
    else num = c;
 
    return (num);
}