/* $Id$ */
/* 
 * Copyright (C)2003-2007 Benny Prijono <benny@prijono.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 */
#include <pj/config.h>

#define WIN32_LEAN_AND_MEAN
#include <windows.h>

/* PMIB_ICMP_EX is not declared in VC6, causing error.
 * But EVC4, which also claims to be VC6, does have it! 
 */
#if defined(_MSC_VER) && _MSC_VER==1200 && !defined(PJ_WIN32_WINCE)
#   define PMIB_ICMP_EX void*
#endif
#include <Iphlpapi.h>

#include <pj/ip_helper.h>
#include <pj/assert.h>
#include <pj/errno.h>
#include <pj/string.h>

#ifndef PJ_IP_HELPER_IGNORE_LOOPBACK_IF
#   define PJ_IP_HELPER_IGNORE_LOOPBACK_IF	1
#endif

typedef DWORD (WINAPI *PFN_GetIpAddrTable)(PMIB_IPADDRTABLE pIpAddrTable, 
					   PULONG pdwSize, 
					   BOOL bOrder);
typedef DWORD (WINAPI *PFN_GetIpForwardTable)(PMIB_IPFORWARDTABLE pIpForwardTable,
					      PULONG pdwSize, 
					      BOOL bOrder);
typedef DWORD (WINAPI *PFN_GetIfEntry)(PMIB_IFROW pIfRow);

static HANDLE s_hDLL;
static PFN_GetIpAddrTable s_pfnGetIpAddrTable;
static PFN_GetIpForwardTable s_pfnGetIpForwardTable;
static PFN_GetIfEntry s_pfnGetIfEntry;

static void unload_iphlp_module(void)
{
    FreeLibrary(s_hDLL);
    s_hDLL = NULL;
    s_pfnGetIpAddrTable = NULL;
    s_pfnGetIpForwardTable = NULL;
}

static FARPROC GetIpHlpApiProc(pj_char_t *lpProcName)
{
    if(NULL == s_hDLL) {
	s_hDLL = LoadLibrary(PJ_T("IpHlpApi"));
	if(NULL != s_hDLL) {
	    pj_atexit(&unload_iphlp_module);
	}
    }
	
    if(NULL != s_hDLL)
	return GetProcAddress(s_hDLL, lpProcName);
    
    return NULL;
}

static DWORD MyGetIpAddrTable(PMIB_IPADDRTABLE pIpAddrTable, 
			      PULONG pdwSize, 
			      BOOL bOrder)
{
    if(NULL == s_pfnGetIpAddrTable) {
	s_pfnGetIpAddrTable = (PFN_GetIpAddrTable) 
	    GetIpHlpApiProc(PJ_T("GetIpAddrTable"));
    }
    
    if(NULL != s_pfnGetIpAddrTable) {
	return s_pfnGetIpAddrTable(pIpAddrTable, pdwSize, bOrder);
    }
    
    return ERROR_NOT_SUPPORTED;
}


#if PJ_IP_HELPER_IGNORE_LOOPBACK_IF
static DWORD MyGetIfEntry(MIB_IFROW *pIfRow)
{
    if(NULL == s_pfnGetIfEntry) {
	s_pfnGetIfEntry = (PFN_GetIfEntry) 
	    GetIpHlpApiProc(PJ_T("GetIfEntry"));
    }
    
    if(NULL != s_pfnGetIfEntry) {
	return s_pfnGetIfEntry(pIfRow);
    }
    
    return ERROR_NOT_SUPPORTED;
}
#endif


static DWORD MyGetIpForwardTable(PMIB_IPFORWARDTABLE pIpForwardTable, 
				 PULONG pdwSize, 
				 BOOL bOrder)
{
    if(NULL == s_pfnGetIpForwardTable) {
	s_pfnGetIpForwardTable = (PFN_GetIpForwardTable) 
	    GetIpHlpApiProc(PJ_T("GetIpForwardTable"));
    }
    
    if(NULL != s_pfnGetIpForwardTable) {
	return s_pfnGetIpForwardTable(pIpForwardTable, pdwSize, bOrder);
    }
    
    return ERROR_NOT_SUPPORTED;
}

/*
 * Enumerate the local IP interface currently active in the host.
 */
PJ_DEF(pj_status_t) pj_enum_ip_interface(unsigned *p_cnt,
					 pj_in_addr ifs[])
{
    /* Provide enough buffer or otherwise it will fail with 
     * error 22 ("Not Enough Buffer") error.
     */
    char ipTabBuff[1024];
    MIB_IPADDRTABLE *pTab;
    ULONG tabSize;
    unsigned i, count;
    DWORD rc = NO_ERROR;

    PJ_ASSERT_RETURN(p_cnt && ifs, PJ_EINVAL);

    pTab = (MIB_IPADDRTABLE*)ipTabBuff;

    /* Get IP address table */
    tabSize = sizeof(ipTabBuff);

    rc = MyGetIpAddrTable(pTab, &tabSize, FALSE);
    if (rc != NO_ERROR)
	return PJ_RETURN_OS_ERROR(rc);

    /* Reset result */
    pj_bzero(ifs, sizeof(ifs[0]) * (*p_cnt));

    /* Now fill out the entries */
    count = (pTab->dwNumEntries < *p_cnt) ? pTab->dwNumEntries : *p_cnt;
    *p_cnt = 0;
    for (i=0; i<count; ++i) {
	MIB_IFROW ifRow;

	/* Some Windows returns 0.0.0.0! */
	if (pTab->table[i].dwAddr == 0)
	    continue;

#if PJ_IP_HELPER_IGNORE_LOOPBACK_IF
	/* Investigate the type of this interface */
	pj_bzero(&ifRow, sizeof(ifRow));
	ifRow.dwIndex = pTab->table[i].dwIndex;
	if (MyGetIfEntry(&ifRow) != 0)
	    continue;

	if (ifRow.dwType == MIB_IF_TYPE_LOOPBACK)
	    continue;
#endif

	ifs[*p_cnt].s_addr = pTab->table[i].dwAddr;
	(*p_cnt)++;
    }

    return PJ_SUCCESS;

}


/*
 * Enumerate the IP routing table for this host.
 */
PJ_DEF(pj_status_t) pj_enum_ip_route(unsigned *p_cnt,
				     pj_ip_route_entry routes[])
{
    char ipTabBuff[1024];
    MIB_IPADDRTABLE *pIpTab;
    char rtabBuff[1024];
    MIB_IPFORWARDTABLE *prTab;
    ULONG tabSize;
    unsigned i, count;
    DWORD rc = NO_ERROR;

    PJ_ASSERT_RETURN(p_cnt && routes, PJ_EINVAL);

    pIpTab = (MIB_IPADDRTABLE *)ipTabBuff;
    prTab = (MIB_IPFORWARDTABLE *)rtabBuff;

    /* First get IP address table */
    tabSize = sizeof(ipTabBuff);
    rc = MyGetIpAddrTable(pIpTab, &tabSize, FALSE);
    if (rc != NO_ERROR)
	return PJ_RETURN_OS_ERROR(rc);

    /* Next get IP route table */
    tabSize = sizeof(rtabBuff);

    rc = MyGetIpForwardTable(prTab, &tabSize, 1);
    if (rc != NO_ERROR)
	return PJ_RETURN_OS_ERROR(rc);

    /* Reset routes */
    pj_bzero(routes, sizeof(routes[0]) * (*p_cnt));

    /* Now fill out the route entries */
    count = (prTab->dwNumEntries < *p_cnt) ? prTab->dwNumEntries : *p_cnt;
    *p_cnt = 0;
    for (i=0; i<count; ++i) {
	unsigned j;

	/* Find interface entry */
	for (j=0; j<pIpTab->dwNumEntries; ++j) {
	    if (pIpTab->table[j].dwIndex == prTab->table[i].dwForwardIfIndex)
		break;
	}

	if (j==pIpTab->dwNumEntries)
	    continue;	/* Interface not found */

	routes[*p_cnt].ipv4.if_addr.s_addr = pIpTab->table[j].dwAddr;
	routes[*p_cnt].ipv4.dst_addr.s_addr = prTab->table[i].dwForwardDest;
	routes[*p_cnt].ipv4.mask.s_addr = prTab->table[i].dwForwardMask;

	(*p_cnt)++;
    }

    return PJ_SUCCESS;
}