busybox

/* vi: set sw=4 ts=4: */

/* clientpacket.c

 *

 * Packet generation and dispatching functions for the DHCP client.

 *

 * Russ Dill <Russ.Dill@asu.edu> July 2001

 *

 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.

 */

​

#include <features.h>

#if (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1) || defined _NEWLIB_VERSION

#include <netpacket/packet.h>

#include <net/ethernet.h>

#else

#include <asm/types.h>

#include <linux/if_packet.h>

#include <linux/if_ether.h>

#endif

​

#include "common.h"

#include "dhcpd.h"

#include "dhcpc.h"

#include "options.h"

​

​

/* Create a random xid */

unsigned long random_xid(void)

{

    static int initialized;

    if (!initialized) {

        unsigned long seed;

​

        if (open_read_close("/dev/urandom", &seed, sizeof(seed)) < 0) {

            bb_info_msg("Cannot load seed "

                "from /dev/urandom: %s", strerror(errno));

            seed = time(0);

        }

        srand(seed);

        initialized++;

    }

    return rand();

}

​

​

/* initialize a packet with the proper defaults */

static void init_packet(struct dhcpMessage *packet, char type)

{

    udhcp_init_header(packet, type);

    memcpy(packet->chaddr, client_config.arp, 6);

    if (client_config.clientid)

        add_option_string(packet->options, client_config.clientid);

    if (client_config.hostname) add_option_string(packet->options, client_config.hostname);

    if (client_config.fqdn) add_option_string(packet->options, client_config.fqdn);

    add_option_string(packet->options, client_config.vendorclass);

}

​

​

/* Add a parameter request list for stubborn DHCP servers. Pull the data

 * from the struct in options.c. Don't do bounds checking here because it

 * goes towards the head of the packet. */

static void add_requests(struct dhcpMessage *packet)

{