advertise.c

关于Linux下DHCP支持IPv6的版本实现

#include "stdhead.h"
#include "advertise.h"
#include "lib.h"

struct OPTIONS * copy_client_id (struct DHCP_MESSAGE * solicit_message, struct OPTIONS * opt_ptr)
{
    int flag;
    struct OPTIONS *search_ptr = (struct OPTIONS *) solicit_message -> opt;
    struct DUID *duid_ptr;
    struct DUID3 *duid3_ptr;
    
    while (search_ptr)
    {
	flag = 0;
	
	switch (search_ptr -> u_opt_code.opt_code)
	{
	    case OPTION_CLIENTID :
		flag = 1;
		break;
		
	    case OPTION_IA :
		search_ptr = ((struct IA *) search_ptr -> opt_data) -> opt;
		break;
		
	    case OPTION_IAADDR :
		search_ptr = ((struct IA_ADDRESS *) search_ptr -> opt_data) -> opt;
		break;
	}
	
	if (flag)
	    break;
    }
    
    if (!search_ptr)
	return NULL;
	
    opt_ptr -> u_opt_code.opt_code = OPTION_CLIENTID;
    opt_ptr -> u_opt_len.opt_len = search_ptr -> u_opt_len.opt_len;
    opt_ptr -> opt_data = (struct DUID *) malloc (sizeof (struct DUID));
    duid_ptr = (struct DUID *) opt_ptr -> opt_data;
    duid_ptr -> u_duid_type.duid_type = 3;
    duid_ptr -> duid_type = malloc (sizeof (struct DUID3));
    duid3_ptr = (struct DUID3 *) duid_ptr -> duid_type;
    copy_duid3 ((struct DUID3 *) ((struct DUID *) search_ptr -> opt_data) -> duid_type, duid3_ptr);

    opt_ptr = duid_ptr -> opt = (struct OPTIONS *) malloc (sizeof (struct OPTIONS));
    return opt_ptr;
}

struct OPTIONS * add_ia_option (struct DHCP_MESSAGE * solicit_message, struct addr_details *available_addr, struct OPTIONS * opt_ptr)
{
    int flag;
    struct OPTIONS *search_ptr = (struct OPTIONS *) solicit_message -> opt;
    struct IA *ia_ptr;
    
    while (search_ptr)
    {
	flag = 0;
	
	switch (search_ptr -> u_opt_code.opt_code)
	{
	    case OPTION_CLIENTID :
		search_ptr = ((struct DUID *) search_ptr -> opt_data) -> opt;
		break;
		
	    case OPTION_IA :
		flag = 1;
		break;
		
	    case OPTION_IAADDR :
		search_ptr = ((struct IA_ADDRESS *) search_ptr -> opt_data) -> opt;
		break;
	}
	
	if (flag)
	    break;
    }
    
    if (!search_ptr)
	return NULL;
	
    opt_ptr -> u_opt_code.opt_code = OPTION_IA;
    opt_ptr -> u_opt_len.opt_len = search_ptr -> u_opt_len.opt_len;

    ia_ptr = opt_ptr -> opt_data = (struct IA *) malloc (sizeof (struct IA));
    ia_ptr -> u_iaid.iaid = ((struct IA *) search_ptr -> opt_data) -> u_iaid.iaid;
    ia_ptr -> u_t1.t1 = available_addr -> t1;
    ia_ptr -> u_t2.t2 = available_addr -> t2;
    ia_ptr -> status = Success;

    opt_ptr = ia_ptr -> opt = (struct OPTIONS *) malloc (sizeof (struct OPTIONS));
    return opt_ptr;
}

void add_iaaddr_option (struct DHCP_MESSAGE * solicit_message, struct addr_details *available_addr, struct OPTIONS * opt_ptr)
{
    int flag, i;
    struct OPTIONS *search_ptr = (struct OPTIONS *) solicit_message -> opt;
    struct IA_ADDRESS *ia_addr_ptr;
    
    while (search_ptr)
    {
	flag = 0;
	
	switch (search_ptr -> u_opt_code.opt_code)
	{
	    case OPTION_CLIENTID :
		search_ptr = ((struct DUID *) search_ptr -> opt_data) -> opt;
		break;
		
	    case OPTION_IA :
		search_ptr = ((struct IA *) search_ptr -> opt_data) -> opt;
		break;
		
	    case OPTION_IAADDR :
		flag = 1;
		break;
	}
	
	if (flag)
	    break;
    }
    
    if (!search_ptr)
	return;
	
    opt_ptr -> u_opt_code.opt_code = OPTION_IAADDR;
    opt_ptr -> u_opt_len.opt_len = search_ptr -> u_opt_len.opt_len;

    ia_addr_ptr = opt_ptr -> opt_data = (struct IA_ADDRESS *) malloc (sizeof (struct IA_ADDRESS));
    ia_addr_ptr -> t_bit = 0;
    ia_addr_ptr -> addr_status = Success;
    ia_addr_ptr -> prefix_length = ((struct IA_ADDRESS *) search_ptr -> opt_data) -> prefix_length;
    for (i = 0; i < 16; i++)
	ia_addr_ptr -> addr[i] = available_addr -> ipv6_addr.s6_addr[i];
    ia_addr_ptr -> u_pref_lifetime.pref_lifetime = available_addr -> pref_life;
    ia_addr_ptr -> u_valid_lifetime.valid_lifetime = available_addr -> valid_life;
    ia_addr_ptr -> ia_addr_opt = 0;
    ia_addr_ptr -> opt = 0;
}

struct DHCP_MESSAGE * create_advertise_message (struct DHCP_MESSAGE *solicit_message, struct addr_details *available_addr)
{
    struct DHCP_MESSAGE * dhcp_message_ptr = malloc (sizeof (struct DHCP_MESSAGE));
    struct OPTIONS * opt_ptr;

    // MESSAGE TYPE
    dhcp_message_ptr->u_msg_type.msg_type = ADVERTISE;

    // Copy TRANSACTION ID from solicit message
    dhcp_message_ptr -> u_trans_id.trans_id = solicit_message -> u_trans_id.trans_id;

    // ASSIGN MEMORY FOR OPTIONS
    dhcp_message_ptr->opt = malloc (sizeof (struct OPTIONS));
    opt_ptr = dhcp_message_ptr -> opt;
    
    // copy CLIENT ID OPTION CODE from solicit message
    opt_ptr = copy_client_id (solicit_message, opt_ptr);
	
    // send SERVER Id option
    opt_ptr = send_server_id (opt_ptr);
    
    // Add preference option if specified
    if (available_addr -> pref_val)
	opt_ptr = add_preference_option (available_addr -> pref_val, opt_ptr);
	
    // add IA option
    opt_ptr = add_ia_option (solicit_message, available_addr, opt_ptr);
    
    // add IAADDR option
    add_iaaddr_option (solicit_message, available_addr, opt_ptr);
	
    return dhcp_message_ptr;
}

struct OPTIONS * add_preference_option (int pref_val, struct OPTIONS *opt_ptr)
{
    struct PREFERENCE *pref_ptr;

    opt_ptr -> u_opt_code.opt_code = OPTION_PREFERENCE;
    opt_ptr -> u_opt_len.opt_len = 1;		// Preference value = 1 octet
    pref_ptr = opt_ptr -> opt_data = (struct PREFERENCE *) malloc (sizeof (struct PREFERENCE));

    pref_ptr -> preference_value = pref_val;
    opt_ptr = pref_ptr -> opt = (struct OPTIONS *) malloc (sizeof (struct OPTIONS *));
    return opt_ptr;
}