/*
 *  Template MIB group implementation - at.c
 *
 */

#include <config.h>
#if HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif
#if HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if defined(IFNET_NEEDS_KERNEL) && !defined(_KERNEL)
#define _KERNEL 1
#define _I_DEFINED_KERNEL
#endif
#include <sys/types.h>
#if TIME_WITH_SYS_TIME
# ifdef WIN32
#  include <sys/timeb.h>
# else
# include <sys/time.h>
# endif
# include <time.h>
#else
# if HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif
#if HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif

#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#if HAVE_NET_IF_H
#include <net/if.h>
#endif
#if HAVE_NET_IF_VAR_H
#include <net/if_var.h>
#endif
#ifdef _I_DEFINED_KERNEL
#undef _KERNEL
#endif

#if HAVE_NETINET_IF_ETHER_H
#include <netinet/if_ether.h>
#endif
#if HAVE_INET_MIB2_H
#include <inet/mib2.h>
#endif
#if HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#if HAVE_SYS_SYSCTL_H
#include <sys/sysctl.h>
#endif
#if HAVE_NET_IF_DL_H
#include <net/if_dl.h>
#endif
#if HAVE_SYS_STREAM_H
#include <sys/stream.h>
#endif
#if HAVE_NET_ROUTE_H
#include <net/route.h>
#endif
#ifdef solaris2
#include "kernel_sunos5.h"
#endif
#if HAVE_WINSOCK_H
#include <winsock.h>
#endif
#if HAVE_DMALLOC_H
#include <dmalloc.h>
#endif

#include "mibincl.h"
#include "at.h"
#include "interfaces.h"
#include "auto_nlist.h"
#include "system.h"

#if defined(HAVE_SYS_SYSCTL_H) && !defined(CAN_USE_SYSCTL)
# if defined(RTF_LLINFO) && !defined(irix6)
#  define CAN_USE_SYSCTL 1
# endif
#endif

#ifdef cygwin
#define WIN32
#include <windows.h>
#endif

	/*********************
	 *
	 *  Kernel & interface information,
	 *   and internal forward declarations
	 *
	 *********************/

#ifndef WIN32
#ifndef solaris2
static void ARP_Scan_Init (void);
#ifdef ARP_SCAN_FOUR_ARGUMENTS
static int ARP_Scan_Next (u_long *, char *, u_long *, u_short *);
#else
static int ARP_Scan_Next (u_long *, char *, u_long *);
#endif
#endif
#endif

	/*********************
	 *
	 *  Public interface functions
	 *
	 *********************/

/* define the structure we're going to ask the agent to register our
   information at */
struct variable4 at_variables[] = {
    {ATIFINDEX, ASN_INTEGER, RONLY, var_atEntry, 1, {1}},
    {ATPHYSADDRESS, ASN_OCTET_STR, RONLY, var_atEntry, 1, {2}},
    {ATNETADDRESS, ASN_IPADDRESS, RONLY, var_atEntry, 1, {3}}
};

/* Define the OID pointer to the top of the mib tree that we're
   registering underneath */
oid at_variables_oid[] = { SNMP_OID_MIB2,3,1,1 };

void init_at(void)
{
  /* register ourselves with the agent to handle our mib tree */
  REGISTER_MIB("mibII/at", at_variables, variable4, at_variables_oid);
}

#ifndef WIN32
#ifndef solaris2

/*
  var_atEntry(...
  Arguments:
  vp	  IN      - pointer to variable entry that points here
  name    IN/OUT  - IN/name requested, OUT/name found
  length  IN/OUT  - length of IN/OUT oid's 
  exact   IN      - TRUE if an exact match was requested
  var_len OUT     - length of variable or 0 if function returned
  write_method
  
*/

u_char *
var_atEntry(struct variable *vp,
	    oid *name,
	    size_t *length,
	    int exact,
	    size_t *var_len,
	    WriteMethod **write_method)
{
    /*
     * Address Translation table object identifier is of form:
     * 1.3.6.1.2.1.3.1.1.1.interface.1.A.B.C.D,  where A.B.C.D is IP address.
     * Interface is at offset 10,
     * IPADDR starts at offset 12.
     *
     * IP Net to Media table object identifier is of form:
     * 1.3.6.1.2.1.4.22.1.1.1.interface.A.B.C.D,  where A.B.C.D is IP address.
     * Interface is at offset 10,
     * IPADDR starts at offset 11.
     */
    u_char		    *cp;
    oid			    *op;
    oid			    lowest[16];
    oid			    current[16];
    static char		    PhysAddr[6], LowPhysAddr[6];
    u_long		    Addr, LowAddr, foundone;
#ifdef ARP_SCAN_FOUR_ARGUMENTS
    u_short		    ifIndex, lowIfIndex = 0;
#endif/* ARP_SCAN_FOUR_ARGUMENTS */
    u_long		    ifType, lowIfType = 0;

    int                     oid_length;

    /* fill in object part of name for current (less sizeof instance part) */
    memcpy((char *)current, (char *)vp->name, (int)vp->namelen * sizeof(oid));

    if (current[6] == 3 ) {	/* AT group oid */
	oid_length = 16;
    }
    else {			/* IP NetToMedia group oid */
	oid_length = 15;
    }

    LowAddr = 0;      /* Don't have one yet */
    foundone = 0;
    ARP_Scan_Init();
    for (;;) {
#ifdef ARP_SCAN_FOUR_ARGUMENTS
	if (ARP_Scan_Next(&Addr, PhysAddr, &ifType, &ifIndex) == 0)
	    break;
	current[10] = ifIndex;

	if (current[6] == 3 ) {	/* AT group oid */
	    current[11] = 1;
	    op = current + 12;
	}
	else {			/* IP NetToMedia group oid */
	    op = current + 11;
	}
#else /* ARP_SCAN_FOUR_ARGUMENTS */
	if (ARP_Scan_Next(&Addr, PhysAddr, &ifType) == 0)
	    break;
	current[10] = 1;

	if (current[6] == 3 ) {	/* AT group oid */
	    current[11] = 1;
	    op = current + 12;
	}
	else {			/* IP NetToMedia group oid */
	    op = current + 11;
	}
#endif /* ARP_SCAN_FOUR_ARGUMENTS */
	cp = (u_char *)&Addr;
	*op++ = *cp++;
	*op++ = *cp++;
	*op++ = *cp++;
	*op++ = *cp++;

	if (exact){
	    if (snmp_oid_compare(current, oid_length, name, *length) == 0){
		memcpy( (char *)lowest,(char *)current, oid_length * sizeof(oid));
		LowAddr = Addr;
                foundone = 1;
#ifdef ARP_SCAN_FOUR_ARGUMENTS
		lowIfIndex = ifIndex;
#endif /*  ARP_SCAN_FOUR_ARGUMENTS */
		memcpy( LowPhysAddr,PhysAddr, sizeof(PhysAddr));
		lowIfType = ifType;
		break;	/* no need to search further */
	    }
	} else {
	    if ((snmp_oid_compare(current, oid_length, name, *length) > 0) &&
		 ((foundone == 0) || (snmp_oid_compare(current, oid_length, lowest, oid_length) < 0))){
		/*
		 * if new one is greater than input and closer to input than
		 * previous lowest, save this one as the "next" one.
		 */
		memcpy( (char *)lowest,(char *)current, oid_length * sizeof(oid));
		LowAddr = Addr;
                foundone = 1;
#ifdef ARP_SCAN_FOUR_ARGUMENTS
		lowIfIndex = ifIndex;
#endif /*  ARP_SCAN_FOUR_ARGUMENTS */
		memcpy( LowPhysAddr,PhysAddr, sizeof(PhysAddr));
		lowIfType = ifType;
	    }
	}
    }
    if (foundone == 0)
	return(NULL);

    memcpy( (char *)name,(char *)lowest, oid_length * sizeof(oid));
    *length = oid_length;
    *write_method = 0;
    switch(vp->magic){
	case IPMEDIAIFINDEX:			/* also ATIFINDEX */
	    *var_len = sizeof long_return;
#ifdef ARP_SCAN_FOUR_ARGUMENTS
	    long_return = lowIfIndex;
#else /* ARP_SCAN_FOUR_ARGUMENTS */
#if NO_DUMMY_VALUES
	    return NULL;
#endif
	    long_return = 1; /* XXX */
#endif /* ARP_SCAN_FOUR_ARGUMENTS */
	    return (u_char *)&long_return;
	case IPMEDIAPHYSADDRESS:		/* also ATPHYSADDRESS */
	    *var_len = sizeof(LowPhysAddr);
	    return (u_char *)LowPhysAddr;
	case IPMEDIANETADDRESS:			/* also ATNETADDRESS */
	    *var_len = sizeof long_return;
	    long_return = LowAddr;
	    return (u_char *)&long_return;
	case IPMEDIATYPE:
	    *var_len = sizeof long_return;
	    long_return = lowIfType;
	    return (u_char *)&long_return;
	default:
	    DEBUGMSGTL(("snmpd", "unknown sub-id %d in var_atEntry\n", vp->magic));
   }
   return NULL;
}
#else          /* solaris2 */

typedef struct if_ip {
  int ifIdx;
  IpAddress ipAddr;
} if_ip_t;

static int
AT_Cmp(void *addr, void *ep)
{ mib2_ipNetToMediaEntry_t *mp = (mib2_ipNetToMediaEntry_t *) ep;
  int ret = -1;
  DEBUGMSGTL(("mibII/at", "......... AT_Cmp %lx<>%lx %d<>%d (%.5s)\n",
	  mp->ipNetToMediaNetAddress, ((if_ip_t *)addr)->ipAddr,
	  ((if_ip_t*)addr)->ifIdx,Interface_Index_By_Name (mp->ipNetToMediaIfIndex.o_bytes, mp->ipNetToMediaIfIndex.o_length),
	  mp->ipNetToMediaIfIndex.o_bytes));
  if (mp->ipNetToMediaNetAddress != ((if_ip_t *)addr)->ipAddr)
    ret = 1;
  else if (((if_ip_t*)addr)->ifIdx !=
      Interface_Index_By_Name (mp->ipNetToMediaIfIndex.o_bytes, mp->ipNetToMediaIfIndex.o_length))
	ret = 1;
  else ret = 0;
  DEBUGMSGTL(("mibII/at", "......... AT_Cmp returns %d\n", ret));
  return ret;
}

u_char *
var_atEntry(struct variable *vp,
	    oid *name,
	    size_t *length,
	    int exact,
	    size_t *var_len,
	    WriteMethod **write_method)
{
    /*
     * object identifier is of form:
     * 1.3.6.1.2.1.3.1.1.1.interface.1.A.B.C.D,  where A.B.C.D is IP address.
     * Interface is at offset 10,
     * IPADDR starts at offset 12.
     */
#define AT_MAX_NAME_LENGTH	16
#define AT_IFINDEX_OFF	10
    u_char	*cp;
    oid		*op;
    oid		lowest[AT_MAX_NAME_LENGTH];
    oid		current[AT_MAX_NAME_LENGTH];
    if_ip_t	NextAddr;
    mib2_ipNetToMediaEntry_t entry, Lowentry;
    int		Found = 0;
    req_e	req_type;
    int         offset, olength;

    /* fill in object part of name for current (less sizeof instance part) */

    DEBUGMSGTL(("mibII/at", "var_atEntry: "));
    DEBUGMSGOID(("mibII/at", vp->name, vp->namelen));
    DEBUGMSG(("mibII/at"," %d\n", exact));

    memset (&Lowentry, 0, sizeof (Lowentry));
    memcpy( (char *)current,(char *)vp->name, vp->namelen * sizeof(oid));
    lowest[0] = 1024;
    for (NextAddr.ipAddr = (u_long)-1, NextAddr.ifIdx = 255, req_type = GET_FIRST;
	 ;
	 NextAddr.ipAddr = entry.ipNetToMediaNetAddress,
	 NextAddr.ifIdx = current [AT_IFINDEX_OFF],
	 req_type = GET_NEXT) {
	if (getMibstat(MIB_IP_NET, &entry, sizeof(mib2_ipNetToMediaEntry_t),
		 req_type, &AT_Cmp, &NextAddr) != 0)
		break;
      	current[AT_IFINDEX_OFF] = Interface_Index_By_Name (entry.ipNetToMediaIfIndex.o_bytes, entry.ipNetToMediaIfIndex.o_length);
        if (current[6] == 3 ) {	/* AT group oid */
            current[AT_IFINDEX_OFF+1] = 1;
            offset = AT_IFINDEX_OFF+2;
            olength = AT_IFINDEX_OFF+6;
        } else {
            offset = AT_IFINDEX_OFF+1;
            olength = AT_IFINDEX_OFF+5;
        }
        COPY_IPADDR(cp,(u_char *)&entry.ipNetToMediaNetAddress, op, current+offset);  
	if (exact){
	    if (snmp_oid_compare(current, olength, name, *length) == 0){
		memcpy( (char *)lowest,(char *)current, olength * sizeof(oid));
		Lowentry = entry;
		Found++;
		break;	/* no need to search further */
	    }
	} else {
	    if (snmp_oid_compare(current, olength, name, *length) > 0
	      && snmp_oid_compare(current, olength, lowest, *length) < 0) {
		/*
		 * if new one is greater than input and closer to input than
		 * previous lowest, and is not equal to it, save this one as the "next" one.
		 */
		memcpy( (char *)lowest,(char *)current, olength * sizeof(oid));
		Lowentry = entry;
		Found++;
	    }
	}
    }
    DEBUGMSGTL(("mibII/at", "... Found = %d\n", Found));
    if (Found == 0)
	return(NULL);
    memcpy( (char *)name,(char *)lowest, olength * sizeof(oid));
    *length = olength;
    *write_method = 0;
    switch(vp->magic){
	case IPMEDIAIFINDEX:
	    *var_len = sizeof long_return;
	    long_return = Interface_Index_By_Name(Lowentry.ipNetToMediaIfIndex.o_bytes,
						  Lowentry.ipNetToMediaIfIndex.o_length);
	    return (u_char *)&long_return;
	case IPMEDIAPHYSADDRESS:
	    *var_len = Lowentry.ipNetToMediaPhysAddress.o_length;
	    (void)memcpy(return_buf, Lowentry.ipNetToMediaPhysAddress.o_bytes, *var_len);
	    return (u_char *)return_buf;
	case IPMEDIANETADDRESS:
	    *var_len = sizeof long_return;
	    long_return = Lowentry.ipNetToMediaNetAddress;
	    return (u_char *)&long_return;
	case IPMEDIATYPE:
	    *var_len = sizeof long_return;
	    long_return = Lowentry.ipNetToMediaType;
	    return (u_char *)&long_return;
	default:
	    DEBUGMSGTL(("snmpd", "unknown sub-id %d in var_atEntry\n", vp->magic));
   }
   return NULL;
}
#endif /* solaris2 */


	/*********************
	 *
	 *  Internal implementation functions
	 *
	 *********************/

#ifndef solaris2

static int arptab_size, arptab_current;
#if CAN_USE_SYSCTL
static char *lim, *rtnext;
static char *at = 0;
#else
#ifdef STRUCT_ARPHD_HAS_AT_NEXT
static struct arphd *at=0;
static struct arptab *at_ptr, at_entry;
static struct arpcom  at_com;
#else
static struct arptab *at=0;
#endif
#endif /* CAN_USE_SYSCTL */

static void ARP_Scan_Init (void)
{
#ifndef CAN_USE_SYSCTL
#ifndef linux
	if (!at) {
	    auto_nlist(ARPTAB_SIZE_SYMBOL, (char *)&arptab_size, sizeof arptab_size);
#ifdef STRUCT_ARPHD_HAS_AT_NEXT
          at = (struct arphd  *) malloc(arptab_size * sizeof(struct arphd));
#else
	    at = (struct arptab *) malloc(arptab_size * sizeof(struct arptab));
#endif
	}

#ifdef STRUCT_ARPHD_HAS_AT_NEXT
        auto_nlist(ARPTAB_SYMBOL, (char *)at, arptab_size * sizeof(struct arphd));
        at_ptr = at[0].at_next;
#else
        auto_nlist(ARPTAB_SYMBOL, (char *)at, arptab_size * sizeof(struct arptab));
#endif
	arptab_current = 0;
#else /* linux */
	FILE *in = fopen ("/proc/net/arp", "r");
	int i, n = 0;
        char line [128];
	int za, zb, zc, zd, ze, zf, zg, zh, zi, zj;
        char ifname[20];

	if (!in) {
	 snmp_log(LOG_ERR, "snmpd: Cannot open /proc/net/arp\n");
		arptab_current = 0;
		return;
	}
	for (n = -1; fgets (line, sizeof(line), in); n++)
		;
	fclose (in);
	in = fopen ("/proc/net/arp", "r");
	fgets(line, sizeof(line), in);	/* skip header */
	if (at) free (at);
	arptab_current = 0; /* it was missing, bug??? */
	arptab_size = n;
	if (arptab_size > 0)
		at = (struct arptab *)
                  malloc (arptab_size * sizeof (struct arptab));
	else
		at = NULL;
	for (i = 0; i < arptab_size; i++) {
		u_long tmp_a;
		while (line == fgets (line, sizeof(line), in) &&
			12 != sscanf (line, "%d.%d.%d.%d 0x%*x 0x%x %x:%x:%x:%x:%x:%x %*[^ ] %20s\n",
			&za, &zb, &zc, &zd, &at[i].at_flags,
			&ze, &zf, &zg, &zh, &zi, &zj, ifname)) {
			snmp_log(LOG_ERR, "Bad line in /proc/net/arp: %s", line);
			continue;
		    }
		at [i].at_enaddr[0] = ze;
		at [i].at_enaddr[1] = zf;
		at [i].at_enaddr[2] = zg;
		at [i].at_enaddr[3] = zh;
		at [i].at_enaddr[4] = zi;
		at [i].at_enaddr[5] = zj;
		tmp_a = ((u_long)za << 24) |
			((u_long)zb << 16) |
			((u_long)zc <<  8) |
			((u_long)zd      ) ;
		at [i].at_iaddr.s_addr = htonl(tmp_a);
		at [i].if_index = Interface_Index_By_Name(ifname, strlen(ifname));
	}
	fclose (in);
#endif /* linux */
#else /* CAN_USE_SYSCTL */
	int mib[6];
	size_t needed;

	mib[0] = CTL_NET;
	mib[1] = PF_ROUTE;
	mib[2] = 0;
	mib[3] = AF_INET;
	mib[4] = NET_RT_FLAGS;
	mib[5] = RTF_LLINFO;

	if (at)
		free(at);
	if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
		snmp_log_perror("route-sysctl-estimate");
	if ((at = malloc(needed ? needed : 1)) == NULL)
		snmp_log_perror("malloc");
	if (sysctl(mib, 6, at, &needed, NULL, 0) < 0)
		snmp_log_perror("actual retrieval of routing table");
	lim = at + needed;
	rtnext = at;
#endif /* CAN_USE_SYSCTL */
}

#ifdef ARP_SCAN_FOUR_ARGUMENTS
static int ARP_Scan_Next(u_long *IPAddr, char *PhysAddr, u_long *ifType, u_short *ifIndex)
#else
static int ARP_Scan_Next(u_long *IPAddr, char *PhysAddr, u_long *ifType)
#endif
{
#ifndef CAN_USE_SYSCTL
#ifdef linux
	if (arptab_current<arptab_size)
	{
		/* copy values */
		*IPAddr= at[arptab_current].at_iaddr.s_addr;
		*ifType= (at[arptab_current].at_flags & ATF_PERM) ? 4/*static*/ : 3/*dynamic*/ ;
		*ifIndex = at[arptab_current].if_index;
		memcpy( PhysAddr, &at[arptab_current].at_enaddr,
				sizeof(at[arptab_current].at_enaddr) );
		
		/* increment to point next entry */
		arptab_current++;
		/* return success */
		return( 1 );
	}
#endif /* linux */
  return 0; /* we need someone with an irix box to fix this section */
#else
#if !defined(ARP_SCAN_FOUR_ARGUMENTS) || defined(hpux)
	register struct arptab *atab;

	while (arptab_current < arptab_size) {
#ifdef STRUCT_ARPHD_HAS_AT_NEXT
              /* The arp table is an array of linked lists of arptab entries.
                 Unused slots have pointers back to the array entry itself */

              if ( at_ptr == (auto_nlist_value(ARPTAB_SYMBOL) +
                              arptab_current*sizeof(struct arphd))) {
                      /* Usused */
                  arptab_current++;
                  at_ptr = at[arptab_current].at_next;
                  continue;
              }

              klookup( at_ptr, (char *)&at_entry, sizeof(struct arptab));
              klookup( at_entry.at_ac, (char *)&at_com, sizeof(struct arpcom));

              at_ptr = at_entry.at_next;
              atab = &at_entry;
              *ifIndex = at_com.ac_if.if_index;       /* not strictly ARPHD */
#else /* STRUCT_ARPHD_HAS_AT_NEXT */
		atab = &at[arptab_current++];
#endif /* STRUCT_ARPHD_HAS_AT_NEXT */
		if (!(atab->at_flags & ATF_COM)) continue;
		*ifType = (atab->at_flags & ATF_PERM) ? 4 : 3 ;
		*IPAddr = atab->at_iaddr.s_addr;
#if defined (sunV3) || defined(sparc) || defined(hpux)
		memcpy( PhysAddr,(char *) &atab->at_enaddr, sizeof(atab->at_enaddr));
#endif
#if defined(mips) || defined(ibm032) 
		memcpy( PhysAddr,(char *)  atab->at_enaddr, sizeof(atab->at_enaddr));
#endif
	return(1);
	}
#else /* !defined(ARP_SCAN_FOUR_ARGUMENTS) || defined(hpux) */
	struct rt_msghdr *rtm;
	struct sockaddr_inarp *sin;
	struct sockaddr_dl *sdl;

	while (rtnext < lim) {
		rtm = (struct rt_msghdr *)rtnext;
		sin = (struct sockaddr_inarp *)(rtm + 1);
		sdl = (struct sockaddr_dl *)(sin + 1);
		rtnext += rtm->rtm_msglen;
		if (sdl->sdl_alen) {
			*IPAddr = sin->sin_addr.s_addr;
			memcpy( PhysAddr,(char *) LLADDR(sdl), sdl->sdl_alen);
			*ifIndex = sdl->sdl_index;
			*ifType = 1;	/* XXX */
			return(1);
		}
	}
#endif /* !defined(ARP_SCAN_FOUR_ARGUMENTS) || defined(hpux) */
	return(0);	    /* "EOF" */
#endif /* !CAN_USE_SYSCTL */
}
#endif /* solaris2 */

#else /* WIN32 */
#include <iphlpapi.h>

extern WriteMethod write_arp;
MIB_IPNETROW *arp_row = NULL;
int create_flag = 0;

u_char *
var_atEntry(struct variable *vp,
            oid *name,
            size_t *length,
            int exact,
            size_t *var_len,
            WriteMethod **write_method)
{
    /*
     * Address Translation table object identifier is of form:
     * 1.3.6.1.2.1.3.1.?.interface.1.A.B.C.D,  where A.B.C.D is IP address.
     * Interface is at offset 10,
     * IPADDR starts at offset 12.
     *
     * IP Net to Media table object identifier is of form:
     * 1.3.6.1.2.1.4.22.1.?.interface.A.B.C.D,  where A.B.C.D is IP address.
     * Interface is at offset 10,
     * IPADDR starts at offset 11.
     */
    u_char                    *cp;
    oid                            *op;
    oid                            lowest[16];
    oid                            current[16];
    int         oid_length;
    int         lowState = -1; /* Don't have one yet */
    PMIB_IPNETTABLE pIpNetTable = NULL;
    DWORD status = NO_ERROR;
    DWORD dwActualSize = 0;
    UINT i;
    u_char dest_addr[4];

    /* fill in object part of name for current (less sizeof instance part) */
    memcpy((char *)current, (char *)vp->name, (int)vp->namelen * sizeof(oid));

    if (current[6] == 3 ) {        /* AT group oid */
       oid_length = 16;
    }
    else {                        /* IP NetToMedia group oid */
       oid_length = 15;
    }
    
    status = GetIpNetTable(pIpNetTable, &dwActualSize, TRUE);
    if (status == ERROR_INSUFFICIENT_BUFFER)
    {
        pIpNetTable = (PMIB_IPNETTABLE) malloc(dwActualSize);
        if(pIpNetTable != NULL){  
            /* Get the sorted IpNet Table */
            status = GetIpNetTable(pIpNetTable, &dwActualSize, TRUE);
        }
    }


    if(status == NO_ERROR)
    {
        for (i = 0; i < pIpNetTable->dwNumEntries; ++i)
        {
            current[10] =  pIpNetTable->table[i].dwIndex;
            
            
            if (current[6] == 3 ) {        /* AT group oid */
                current[11] = 1;
                op = current + 12;
            }
            else {                        /* IP NetToMedia group oid */
                op = current + 11;
            }
            cp = (u_char *)&pIpNetTable->table[i].dwAddr;
            *op++ = *cp++;
            *op++ = *cp++;
            *op++ = *cp++;
            *op++ = *cp++;

            if (exact){
                if (snmp_oid_compare(current, oid_length, name, *length) == 0){
                    memcpy( (char *)lowest,(char *)current, oid_length * sizeof(oid));
                    lowState = 0;
                    break;        /* no need to search further */
                }
            } else {
                if (snmp_oid_compare(current, oid_length, name, *length) > 0){
                    memcpy( (char *)lowest,(char *)current, oid_length * sizeof(oid));
                    lowState = 0;
                    break; /* As the table is sorted, no need to search further */
                }
            }
        }
    }
    if(arp_row == NULL){
     /* Free allocated memory in case of SET request's FREE phase */
      arp_row = (PMIB_IPNETROW)malloc(sizeof(MIB_IPNETROW));
    }

    if (lowState < 0 || status != NO_ERROR){
      /* for creation of new row, only ipNetToMediaTable case is considered */
      if(*length == 15 || *length == 16){
        create_flag = 1; 
        *write_method = write_arp; 
        arp_row->dwIndex = name[10];

        if(*length == 15)/* ipNetToMediaTable */
        {
          i = 11;
        }else /* at Table */
        {
          i = 12;
        }
       
        dest_addr[0] = (u_char)name[i];
        dest_addr[1] = (u_char)name[i+1];
        dest_addr[2] = (u_char)name[i+2];
        dest_addr[3] = (u_char) name[i+3];
        arp_row->dwAddr = *((DWORD *)dest_addr);

        arp_row->dwType = 4; /* Static */
        arp_row->dwPhysAddrLen = 0;        
      }      
        free(pIpNetTable);
        return(NULL);
    }
    
    create_flag = 0;
    memcpy((char *)name,(char *)lowest, oid_length * sizeof(oid));
    *length = oid_length;
    *write_method = write_arp;
    *arp_row = pIpNetTable->table[i];

    switch(vp->magic){
        case IPMEDIAIFINDEX:                        /* also ATIFINDEX */
            *var_len = sizeof long_return;
            long_return = pIpNetTable->table[i].dwIndex;
            free(pIpNetTable);
            return (u_char *)&long_return;
        case IPMEDIAPHYSADDRESS:                /* also ATPHYSADDRESS */
            *var_len = pIpNetTable->table[i].dwPhysAddrLen;
            memcpy(return_buf, pIpNetTable->table[i].bPhysAddr, *var_len);
            free(pIpNetTable);
            return (u_char *)return_buf;
        case IPMEDIANETADDRESS:                        /* also ATNETADDRESS */
            *var_len = sizeof long_return;
            long_return = pIpNetTable->table[i].dwAddr;
            free(pIpNetTable);
            return (u_char *)&long_return;
        case IPMEDIATYPE:
            *var_len = sizeof long_return;
            long_return = pIpNetTable->table[i].dwType;
            free(pIpNetTable);
            return (u_char *)&long_return;
        default:
            DEBUGMSGTL(("snmpd", "unknown sub-id %d in var_atEntry\n", vp->magic));
   }
   return NULL;
}

int
write_arp(
   int      action,
   u_char   *var_val,
   u_char   var_val_type,
   size_t   var_val_len,
   u_char   *statP,
   oid      *name,
   size_t   length)
{
  int var, retval = SNMP_ERR_NOERROR ;
  static PMIB_IPNETROW oldarp_row = NULL;
  MIB_IPNETROW temp_row;
  DWORD status = NO_ERROR;

    /*
     * IP Net to Media table object identifier is of form:
     * 1.3.6.1.2.1.4.22.1.?.interface.A.B.C.D,  where A.B.C.D is IP address.
     * Interface is at offset 10,
     * IPADDR starts at offset 11.
     */

    if (name[6] == 3 ) {	/* AT group oid */
	if (length != 16) {
          snmp_log(LOG_ERR, "length error\n");
          return SNMP_ERR_NOCREATION;
        }
    }
    else {			/* IP NetToMedia group oid */
	if (length != 15) {
           snmp_log(LOG_ERR, "length error\n");
           return SNMP_ERR_NOCREATION;
        }
    }
  

  /* #define for ipNetToMediaTable entries are 1 less than corresponding sub-id in MIB
   * i.e. IPMEDIAIFINDEX defined as 0, but ipNetToMediaIfIndex registered as 1
   */
  var = name[9] - 1;
  switch(action) {
    case RESERVE1:    
      switch(var){
        case IPMEDIAIFINDEX: 
          if (var_val_type != ASN_INTEGER){
            snmp_log(LOG_ERR, "not integer\n");
            return SNMP_ERR_WRONGTYPE;
          }
          if((*((int *)var_val)) < 0 ){
            snmp_log(LOG_ERR, "invalid media ifIndex");
            return SNMP_ERR_WRONGVALUE;
          }
          if (var_val_len > sizeof(int)){
            snmp_log(LOG_ERR, "bad length\n");
            return SNMP_ERR_WRONGLENGTH;
          }
          break;
        case IPMEDIANETADDRESS:
          if (var_val_type != ASN_IPADDRESS){
            snmp_log(LOG_ERR, "not IP Address\n");
            return SNMP_ERR_WRONGTYPE;
          }
          if((*((int *)var_val)) < 0 ){
            snmp_log(LOG_ERR, "invalid media net address");
            return SNMP_ERR_WRONGVALUE;
          }
          if (var_val_len > sizeof(DWORD)){
            snmp_log(LOG_ERR, "bad length\n");
            return SNMP_ERR_WRONGLENGTH;
          }
          break;
        case IPMEDIATYPE: 
          if (var_val_type != ASN_INTEGER){
            snmp_log(LOG_ERR, "not integer\n");
            return SNMP_ERR_WRONGTYPE;
          }
          if((*((int *)var_val)) < 1 || (*((int *)var_val)) > 4 ){
            snmp_log(LOG_ERR, "invalid media type");
            return SNMP_ERR_WRONGVALUE;
          }
          if (var_val_len > sizeof(int)){
            snmp_log(LOG_ERR, "bad length\n");
            return SNMP_ERR_WRONGLENGTH;
          }
          break;
        case IPMEDIAPHYSADDRESS:
          if (var_val_type != ASN_OCTET_STR) {
            snmp_log(LOG_ERR, "not octet str");
            return SNMP_ERR_WRONGTYPE;
          }
          if (var_val_len != 6) {
            snmp_log(LOG_ERR, "not correct ipAddress length: %d", var_val_len);
            return SNMP_ERR_WRONGLENGTH;
          }
          break;
        default:
          DEBUGMSGTL(("snmpd", "unknown sub-id %d in write_rte\n", var+1));
        	return SNMP_ERR_NOTWRITABLE;
      }
      break;
    case RESERVE2:
      /* Save the old value, in case of UNDO */
      if(oldarp_row == NULL){
        oldarp_row = (PMIB_IPNETROW) malloc(sizeof(MIB_IPNETROW));
        *oldarp_row = *arp_row;
      }
      break;
    case  ACTION:	/* Perform the SET action (if reversible) */
      switch(var){
        
        case IPMEDIAIFINDEX: 
          temp_row = *arp_row;
          arp_row->dwIndex  = *((int *)var_val) ;
          /* In case of new entry, physical address is mandatory.
           * SetIpNetEntry will be done in COMMIT case 
          */
          if(!create_flag){
            if(SetIpNetEntry(arp_row) != NO_ERROR){
              arp_row->dwIndex = temp_row.dwIndex;
              retval = SNMP_ERR_COMMITFAILED;
            }
          //Don't know yet, whether change in ifIndex creates new row or not
          //else{
            //temp_row.dwType = 2;
            //if(SetIpNetEntry(&temp_row) != NO_ERROR)
              //retval = SNMP_ERR_COMMITFAILED;
          //}
          }
          break;
        case IPMEDIANETADDRESS:
          temp_row = *arp_row;
          arp_row->dwAddr  = *((int *)var_val);
          if(!create_flag){
            if(SetIpNetEntry(arp_row) != NO_ERROR){
              arp_row->dwAddr = oldarp_row->dwAddr;
              retval = SNMP_ERR_COMMITFAILED;
            }else{
              temp_row.dwType = 2;
              if(SetIpNetEntry(&temp_row) != NO_ERROR){
                snmp_log(LOG_ERR, "Failed in ACTION, while deleting old row \n");
                retval = SNMP_ERR_COMMITFAILED;
              }
            } 
          }
          break;
        case IPMEDIATYPE:
          arp_row->dwType  = *((int *)var_val);
          if(!create_flag){
            if(SetIpNetEntry(arp_row) != NO_ERROR)
              retval = SNMP_ERR_COMMITFAILED;   
          }
          break;
        case IPMEDIAPHYSADDRESS:
          memcpy(arp_row->bPhysAddr, var_val, var_val_len);
          arp_row->dwPhysAddrLen = var_val_len;
          if(!create_flag){
            if(SetIpNetEntry(arp_row) != NO_ERROR)
              retval = SNMP_ERR_COMMITFAILED;
          }
          break;
        default:
          DEBUGMSGTL(("snmpd", "unknown sub-id %d in write_arp\n", var+1));
        	retval = SNMP_ERR_NOTWRITABLE;
      }
      return retval;
    case UNDO :
      /* Reverse the SET action and free resources */            
      if(oldarp_row != NULL){   
        //UNDO the changes done for existing entry.
        if(!create_flag){
          if((status = SetIpNetEntry(oldarp_row)) != NO_ERROR){
            snmp_log(LOG_ERR, "Error in case UNDO, status : %d\n", status);            
            retval = SNMP_ERR_UNDOFAILED;
          } 
        }

        if(oldarp_row->dwAddr != arp_row->dwAddr){
          arp_row->dwType = 2; //If row was added/created delete that row
          
          if((status = SetIpNetEntry(arp_row)) != NO_ERROR){
            snmp_log(LOG_ERR, "Error while deleting added row, status : %d\n", 
                   status);            
            retval = SNMP_ERR_UNDOFAILED;
          }
        } 
        free(oldarp_row);
        oldarp_row = NULL;
        free(arp_row);
        arp_row = NULL; 
        return retval;
      }
      break;
    case COMMIT:
      /*  if new entry and physical address specified, create new entry */
      if(create_flag) {
        if(arp_row->dwPhysAddrLen != 0){
          if((status =CreateIpNetEntry(arp_row) )!= NO_ERROR){
            snmp_log(LOG_ERR, "Inside COMMIT: CreateIpNetEntry failed, status %d\n", status);
            retval = SNMP_ERR_COMMITFAILED;
          }          
        }else{
          /*For new entry, physical address must be set. */
          snmp_log(LOG_ERR, "Can't create new entry without physical address\n");
          retval = SNMP_ERR_WRONGVALUE;
        }
        /* unset the create_flag, so that CreateIpNetEntry called only once */
        create_flag = 0;
      }
                
    case FREE:       
      /* Free any resources allocated */     
      free(oldarp_row);
      oldarp_row = NULL;
      free(arp_row);
      arp_row = NULL;            
      break;
  }
  return retval;
}
#endif /* WIN32 */
