int arpCheck()
{
arpMessage ArpMsgSend,ArpMsgRecv;
#ifdef OLD_LINUX_VERSION
struct sockaddr addr;
int j;
#endif
int i=0;
memset(&ArpMsgSend,0,sizeof(arpMessage));
memcpy(ArpMsgSend.ethhdr.ether_dhost,MAC_BCAST_ADDR,ETH_ALEN);
memcpy(ArpMsgSend.ethhdr.ether_shost,ClientHwAddr,ETH_ALEN);
ArpMsgSend.ethhdr.ether_type = htons(ETHERTYPE_ARP);
ArpMsgSend.htype = htons(ARPHRD_ETHER);
ArpMsgSend.ptype = htons(ETHERTYPE_IP);
ArpMsgSend.hlen = ETH_ALEN;
ArpMsgSend.plen = 4;
ArpMsgSend.operation = htons(ARPOP_REQUEST);
memcpy(ArpMsgSend.sHaddr,ClientHwAddr,ETH_ALEN);
memcpy(&ArpMsgSend.tInaddr,&DhcpIface.ciaddr,4);
DebugSyslog(LOG_DEBUG,
"broadcasting ARPOP_REQUEST for %u.%u.%u.%u\n",
ArpMsgSend.tInaddr[0],ArpMsgSend.tInaddr[1],
ArpMsgSend.tInaddr[2],ArpMsgSend.tInaddr[3]);
do
{
do
{
if ( i++ > 4 ) return 0; /* 5 probes */
#ifdef OLD_LINUX_VERSION
memset(&addr,0,sizeof(struct sockaddr));
memcpy(addr.sa_data,IfName,IfName_len);
if ( sendto(dhcpSocket,&ArpMsgSend,sizeof(arpMessage),0,
&addr,sizeof(struct sockaddr)) == -1 )
#else
if ( send(dhcpSocket,&ArpMsgSend,sizeof(arpMessage),0) == -1 )
#endif
{
syslog(LOG_ERR,"arpCheck: sendto: %m\n");
return -1;
}
}
while ( peekfd(dhcpSocket,50000) ); /* 50 msec timeout */
do
{
if ( recv(dhcpSocket,&ArpMsgRecv,sizeof(arpMessage),0) == -1 )
{
syslog(LOG_ERR,"arpCheck: recv: %m\n");
return -1;
}
if ( ArpMsgRecv.ethhdr.ether_type != htons(ETHERTYPE_ARP) )
continue;
if ( ArpMsgRecv.operation == htons(ARPOP_REPLY) )
{
DebugSyslog(LOG_DEBUG,
"ARPOP_REPLY received from %u.%u.%u.%u for %u.%u.%u.%u\n",
ArpMsgRecv.sInaddr[0],ArpMsgRecv.sInaddr[1],
ArpMsgRecv.sInaddr[2],ArpMsgRecv.sInaddr[3],
ArpMsgRecv.tInaddr[0],ArpMsgRecv.tInaddr[1],
ArpMsgRecv.tInaddr[2],ArpMsgRecv.tInaddr[3]);
}
else
continue;
if ( memcmp(ArpMsgRecv.tHaddr,ClientHwAddr,ETH_ALEN) )
{
DebugSyslog(LOG_DEBUG,
"target hardware address mismatch: %02X.%02X.%02X.%02X.%02X.%02X received, %02X.%02X.%02X.%02X.%02X.%02X expected\n",
ArpMsgRecv.tHaddr[0],ArpMsgRecv.tHaddr[1],ArpMsgRecv.tHaddr[2],
ArpMsgRecv.tHaddr[3],ArpMsgRecv.tHaddr[4],ArpMsgRecv.tHaddr[5],
ClientHwAddr[0],ClientHwAddr[1],
ClientHwAddr[2],ClientHwAddr[3],
ClientHwAddr[4],ClientHwAddr[5]);
continue;
}
if ( memcmp(&ArpMsgRecv.sInaddr,&DhcpIface.ciaddr,4) )
{
DebugSyslog(LOG_DEBUG,
"sender IP address mismatch: %u.%u.%u.%u received, %u.%u.%u.%u expected\n",
ArpMsgRecv.sInaddr[0],ArpMsgRecv.sInaddr[1],ArpMsgRecv.sInaddr[2],ArpMsgRecv.sInaddr[3],
((unsigned char *)&DhcpIface.ciaddr)[0],
((unsigned char *)&DhcpIface.ciaddr)[1],
((unsigned char *)&DhcpIface.ciaddr)[2],
((unsigned char *)&DhcpIface.ciaddr)[3]);
continue;
}
return 1;
}
while ( peekfd(dhcpSocket,50000) == 0 );
}
while ( 1 );
return 0;
}
int parseDhcpMsgRecv() /* this routine parses dhcp message received */
{
#ifdef DEBUG
int i,j;
#endif
register u_char *p = DhcpMsgRecv->options+4;
unsigned char *end = DhcpMsgRecv->options+sizeof(DhcpMsgRecv->options);
while ( p < end )
switch ( *p )
{
case endOption: goto swend;
case padOption: p++; break;
default:
/* Handle a bug in the redhat 6.2 bootp server
* which causes it to incorrectly pad the end option */
if ( ((p - DhcpMsgRecv->options)&1) && (p[1] == endOption) )
goto swend;
if ( p[1] )
{
if ( DhcpOptions.len[*p] == p[1] )
memcpy(DhcpOptions.val[*p],p+2,p[1]);
else
{
DhcpOptions.len[*p] = p[1];
if ( DhcpOptions.val[*p] )
free(DhcpOptions.val[*p]);
else
DhcpOptions.num++;
DhcpOptions.val[*p] = malloc(p[1]+1);
memset(DhcpOptions.val[*p],0,p[1]+1);
memcpy(DhcpOptions.val[*p],p+2,p[1]);
}
}
p+=p[1]+2;
}
swend:
#ifdef DEBUG
fprintf(stderr,"parseDhcpMsgRecv: %d options received:\n",DhcpOptions.num);
for (i=1;i<255;i++)
if ( DhcpOptions.val[i] )
switch ( i )
{
case 1: /* subnet mask */
case 3: /* routers on subnet */
case 4: /* time servers */
case 5: /* name servers */
case 6: /* dns servers */
case 28:/* broadcast addr */
case 33:/* staticRoute */
case 41:/* NIS servers */
case 42:/* NTP servers */
case 50:/* dhcpRequestdIPaddr */
case 54:/* dhcpServerIdentifier */
for (j=0;j<DhcpOptions.len[i];j+=4)
fprintf(stderr,"i=%-2d len=%-2d option = %u.%u.%u.%u\n",
i,DhcpOptions.len[i],
((unsigned char *)DhcpOptions.val[i])[0+j],
((unsigned char *)DhcpOptions.val[i])[1+j],
((unsigned char *)DhcpOptions.val[i])[2+j],
((unsigned char *)DhcpOptions.val[i])[3+j]);
break;
case 2: /* time offset */
case 51:/* dhcpAddrLeaseTime */
case 57:/* dhcpMaxMsgSize */
case 58:/* dhcpT1value */
case 59:/* dhcpT2value */
fprintf(stderr,"i=%-2d len=%-2d option = %d\n",
i,DhcpOptions.len[i],
ntohl(*(int *)DhcpOptions.val[i]));
break;
case 23:/* defaultIPTTL */
case 29:/* performMaskdiscovery */
case 31:/* performRouterdiscovery */
case 53:/* dhcpMessageType */
fprintf(stderr,"i=%-2d len=%-2d option = %u\n",
i,DhcpOptions.len[i],*(unsigned char *)DhcpOptions.val[i]);
break;
default:
fprintf(stderr,"i=%-2d len=%-2d option = \"%s\"\n",
i,DhcpOptions.len[i],(char *)DhcpOptions.val[i]);
}
fprintf(stderr,"\
DhcpMsgRecv->yiaddr = %u.%u.%u.%u\n\
DhcpMsgRecv->siaddr = %u.%u.%u.%u\n\
DhcpMsgRecv->giaddr = %u.%u.%u.%u\n\
DhcpMsgRecv->sname = \"%s\"\n\
ServerHardwareAddr = %02X.%02X.%02X.%02X.%02X.%02X\n",
((unsigned char *)&DhcpMsgRecv->yiaddr)[0],
((unsigned char *)&DhcpMsgRecv->yiaddr)[1],
((unsigned char *)&DhcpMsgRecv->yiaddr)[2],
((unsigned char *)&DhcpMsgRecv->yiaddr)[3],
((unsigned char *)&DhcpMsgRecv->siaddr)[0],
((unsigned char *)&DhcpMsgRecv->siaddr)[1],
((unsigned char *)&DhcpMsgRecv->siaddr)[2],
((unsigned char *)&DhcpMsgRecv->siaddr)[3],
((unsigned char *)&DhcpMsgRecv->giaddr)[0],
((unsigned char *)&DhcpMsgRecv->giaddr)[1],
((unsigned char *)&DhcpMsgRecv->giaddr)[2],
((unsigned char *)&DhcpMsgRecv->giaddr)[3],
DhcpMsgRecv->sname,
UdpIpMsgRecv.ethhdr.ether_shost[0],
UdpIpMsgRecv.ethhdr.ether_shost[1],
UdpIpMsgRecv.ethhdr.ether_shost[2],
UdpIpMsgRecv.ethhdr.ether_shost[3],
UdpIpMsgRecv.ethhdr.ether_shost[4],
UdpIpMsgRecv.ethhdr.ether_shost[5]);
#endif
if ( ! DhcpMsgRecv->yiaddr ) DhcpMsgRecv->yiaddr=DhcpMsgSend->ciaddr;
if ( ! DhcpOptions.val[dhcpServerIdentifier] ) /* did not get dhcpServerIdentifier */
{ /* make it the same as IP address of the sender */
DhcpOptions.val[dhcpServerIdentifier] = malloc(4);
memcpy(DhcpOptions.val[dhcpServerIdentifier],&ipRecv->ip_src.s_addr,4);
DhcpOptions.len[dhcpServerIdentifier] = 4;
DhcpOptions.num++;
DebugSyslog(LOG_DEBUG,
"dhcpServerIdentifier option is missing in DHCP server response. Assuming %u.%u.%u.%u\n",
((unsigned char *)DhcpOptions.val[dhcpServerIdentifier])[0],
((unsigned char *)DhcpOptions.val[dhcpServerIdentifier])[1],
((unsigned char *)DhcpOptions.val[dhcpServerIdentifier])[2],
((unsigned char *)DhcpOptions.val[dhcpServerIdentifier])[3]);
}
if ( ! DhcpOptions.val[dns] ) /* did not get DNS */
{ /* make it the same as dhcpServerIdentifier */
DhcpOptions.val[dns] = malloc(4);
memcpy(DhcpOptions.val[dns],DhcpOptions.val[dhcpServerIdentifier],4);
DhcpOptions.len[dns] = 4;
DhcpOptions.num++;
DebugSyslog(LOG_DEBUG,
"dns option is missing in DHCP server response. Assuming %u.%u.%u.%u\n",
((unsigned char *)DhcpOptions.val[dns])[0],
((unsigned char *)DhcpOptions.val[dns])[1],
((unsigned char *)DhcpOptions.val[dns])[2],
((unsigned char *)DhcpOptions.val[dns])[3]);
}
if ( ! DhcpOptions.val[subnetMask] ) /* did not get subnetMask */
{
DhcpOptions.val[subnetMask] = malloc(4);
((unsigned char *)DhcpOptions.val[subnetMask])[0] = 255;
if ( ((unsigned char *)&DhcpMsgRecv->yiaddr)[0] < 128 )
((unsigned char *)DhcpOptions.val[subnetMask])[1] = 0; /* class A */
else
{
((unsigned char *)DhcpOptions.val[subnetMask])[1] = 255;
if ( ((unsigned char *)&DhcpMsgRecv->yiaddr)[0] < 192 )
((unsigned char *)DhcpOptions.val[subnetMask])[2] = 0;/* class B */
else
((unsigned char *)DhcpOptions.val[subnetMask])[2] = 255;/* class C */
}
((unsigned char *)DhcpOptions.val[subnetMask])[3] = 0;
DhcpOptions.len[subnetMask] = 4;
DhcpOptions.num++;
DebugSyslog(LOG_DEBUG,
"subnetMask option is missing in DHCP server response. Assuming %u.%u.%u.%u\n",
((unsigned char *)DhcpOptions.val[subnetMask])[0],
((unsigned char *)DhcpOptions.val[subnetMask])[1],
((unsigned char *)DhcpOptions.val[subnetMask])[2],
((unsigned char *)DhcpOptions.val[subnetMask])[3]);
}
if ( ! DhcpOptions.val[broadcastAddr] ) /* did not get broadcastAddr */
{
int br = DhcpMsgRecv->yiaddr | ~*((int *)DhcpOptions.val[subnetMask]);
DhcpOptions.val[broadcastAddr] = malloc(4);
memcpy(DhcpOptions.val[broadcastAddr],&br,4);
DhcpOptions.len[broadcastAddr] = 4;
DhcpOptions.num++;
DebugSyslog(LOG_DEBUG,
"broadcastAddr option is missing in DHCP server response. Assuming %u.%u.%u.%u\n",
((unsigned char *)DhcpOptions.val[broadcastAddr])[0],
((unsigned char *)DhcpOptions.val[broadcastAddr])[1],
((unsigned char *)DhcpOptions.val[broadcastAddr])[2],
((unsigned char *)DhcpOptions.val[broadcastAddr])[3]);
}
#if 0
if ( ! DhcpOptions.val[routersOnSubnet] )
{
DhcpOptions.val[routersOnSubnet] = malloc(4);
if ( DhcpMsgRecv->giaddr )
memcpy(DhcpOptions.val[routersOnSubnet],&DhcpMsgRecv->giaddr,4);
else
memcpy(DhcpOptions.val[routersOnSubnet],DhcpOptions.val[dhcpServerIdentifier],4);
DhcpOptions.len[routersOnSubnet] = 4;
DhcpOptions.num++;
DebugSyslog(LOG_DEBUG,
"routersOnSubnet option is missing in DHCP server response. Assuming %u.%u.%u.%u\n",
((unsigned char *)DhcpOptions.val[routersOnSubnet])[0],
((unsigned char *)DhcpOptions.val[routersOnSubnet])[1],
((unsigned char *)DhcpOptions.val[routersOnSubnet])[2],
((unsigned char *)DhcpOptions.val[routersOnSubnet])[3]);
}
#endif
if ( DhcpOptions.val[dhcpIPaddrLeaseTime] )
{
if ( *(unsigned int *)DhcpOptions.val[dhcpIPaddrLeaseTime] == 0 )
{
memcpy(DhcpOptions.val[dhcpIPaddrLeaseTime],&nleaseTime,4);
DebugSyslog(LOG_DEBUG,
"dhcpIPaddrLeaseTime=0 in DHCP server response. Assuming %u sec\n",
LeaseTime);
}
}
else /* did not get dhcpIPaddrLeaseTime */
{
DhcpOptions.val[dhcpIPaddrLeaseTime] = malloc(4);
memcpy(DhcpOptions.val[dhcpIPaddrLeaseTime],&nleaseTime,4);
DhcpOptions.len[dhcpIPaddrLeaseTime] = 4;
DhcpOptions.num++;
DebugSyslog(LOG_DEBUG,"dhcpIPaddrLeaseTime option is missing in DHCP server response. Assuming %u sec\n",LeaseTime);
}
if ( ! DhcpOptions.val[dhcpT1value] ) /* did not get T1 */
{
int t1 = htonl((unsigned )(0.5*ntohl(*(unsigned int *)DhcpOptions.val[dhcpIPaddrLeaseTime])));
DhcpOptions.val[dhcpT1value] = malloc(4);
memcpy(DhcpOptions.val[dhcpT1value],&t1,4);
DhcpOptions.len[dhcpT1value] = 4;
DhcpOptions.num++;
}
if ( ! DhcpOptions.val[dhcpT2value] ) /* did not get T2 */
{
int t2 = htonl((unsigned )(0.875*ntohl(*(unsigned int *)DhcpOptions.val[dhcpIPaddrLeaseTime])));
DhcpOptions.val[dhcpT2value] = malloc(4);
memcpy(DhcpOptions.val[dhcpT2value],&t2,4);
DhcpOptions.len[dhcpT2value] = 4;
DhcpOptions.num++;
}
if ( DhcpOptions.val[dhcpMessageType] )
return *(unsigned char *)DhcpOptions.val[dhcpMessageType];
return 0;
}
