Why does dhcp client require a router (gateway) specification?

[Peter Dufault]

If I don't specify a router in the dhcpd.conf file for the system that provides leases to the RTEMS dhcp client when the lease time is 1/2 over I start to get these messages on the console.  118 is "EHOSTUNREACH".

++
bootpc_call: sosend: 118
bootpc_call: sosend: 118
BOOTP timeout for server 255.255.255.255
DHCP call failed -- error 116bootpc_call: sosend: 118
--

I get this logged at boot, note the gw 0.0.0.0 and the "error=114" message (ENETUNREACH):

++
dhcpc: smc: inet: 192.168.240.36  mask: 255.255.255.0  
             srv: 192.168.240.4     gw: 0.0.0.0        
bootpc_adjust_interface: add net route, error=114
--

ifconfig shows that both the netmask and broadcast address for SMC0 are correct:

++
Ethernet Address: 50:2D:F4:01:D5:12
Address:192.168.240.36  Broadcast Address:192.168.240.255 Net mask:255.255.255.0   
Flags: Up Broadcast Running Simplex
--

Here is the routing table:

++
[/] # route
Destination     Gateway/Mask/Hw    Flags     Refs     Use Expire Interface
127.0.0.1       127.0.0.1          UH          0        0      0 lo0
192.168.240.0   255.255.255.0      U           0        0      4 smc0
192.168.240.4   00:21:9B:01:EF:D0  UHL         1     1494   1209 smc0
[/] # 
--

If I specify a router in dhcpd.conf, even to something that doesn't exist ("option routers 192.168.240.1;"), then DHCP works OK.  Boot up is like this:

++
dhcpc: smc: inet: 192.168.240.36  mask: 255.255.255.0
             srv: 192.168.240.4     gw: 192.168.240.1
--

And the routing table is like this:

++
[/] # route
Destination     Gateway/Mask/Hw    Flags     Refs     Use Expire Interface
default         192.168.240.1      UGS         1        0      0 smc0
127.0.0.1       127.0.0.1          UH          0        0      0 lo0
192.168.240.0   255.255.255.0      U           0        0      4 smc0
192.168.240.1                      UHL         2        0      4 smc0
192.168.240.4   00:21:9B:01:EF:D0  UHL         1     1494   1209 smc0
255.255.255.255 192.168.240.1      UGH         0        1   3634 smc0
[/] # 
--

I don't want the embedded system to have a default router.  Is there something I need to do in my dhcp client setup, or is this a defect in RTEMS dhcpd?

Peter
-----------------
Peter Dufault
HD Associates, Inc.      Software and System Engineering