File content as of revision 2:540f6e142d59:

/*********************************************************************
PicoTCP. Copyright (c) 2012 TASS Belgium NV. Some rights reserved.
See LICENSE and COPYING for usage.

.

Authors: Frederik Van Slycken
*********************************************************************/

#include "pico_config.h"
#include "pico_stack.h"
#include "pico_dhcp_common.h"

#if defined (PICO_SUPPORT_DHCPC) || defined (PICO_SUPPORT_DHCPD)
//this function should only be used after you checked if the options are valid! otherwise it could read from bad memory!
uint8_t dhcp_get_next_option(uint8_t *begin, uint8_t *data, int *len, uint8_t **nextopt)
{
    uint8_t *p;
    uint8_t type;
    uint8_t opt_len;

    if (!begin)
        p = *nextopt;
    else
        p = begin;

    type = *p;
    *nextopt = ++p;
    if ((type == PICO_DHCPOPT_END) || (type == PICO_DHCPOPT_PAD)) {
        memset(data, 0, *len);
        len = 0;
        return type;
    }
    opt_len = *p;
    p++;
    if (*len > opt_len)
        *len = opt_len;
    memcpy(data, p, *len);
    *nextopt = p + opt_len;
    return type;
}

int is_options_valid(uint8_t *opt_buffer, int len)
{
    uint8_t *p = opt_buffer;
    while (len > 0) {
        if (*p == PICO_DHCPOPT_END)
            return 1;
        else if (*p == PICO_DHCPOPT_PAD) {
            p++;
            len--;
        } else {
            uint8_t opt_len;
            p++;
            len--;
            if(len > 0) {
                opt_len = *p;
                p += opt_len + 1;
                len -= opt_len;
            }else
                return 0;
        }
    }
    return 0;
}

#endif