[En-Nut-Discussion] RFC: Extending Network Configuration

[Michael Jones]

Hello!

I'm currently working on adding a few things to Nut/OS. One being SNTP
resolution via DHCP. In the course of this I have stumbled across a few
details that require some changes.

The first is that the NUTCONF structure will have to grow to add IP
Addresses for DNS (two entries) and NTP. There is not much what we can do
about NUTCONF growing - it was bound to happed one day - so anybody that has
data stored in the EEPROM right behind NUTCONF will have to shift that data.


The second set of changes is how NutNetIfConfig2(...) / NutNetIfSetup(...)
works. Currently everything is passed as parameters so adding DNS and NTP
and whatever will come next will make these functions very unhandy. I
therefore am suggesting a set of functions to set and retrieve individual
NutConfig options (see below). 

The final addition results from the current situation that different modules
have to refer each other due to them having to exchange information. One
example being that NutDnsConfig(...) is called by DHCP to activate any
received DNS servers, thereby forcing the DNS to be linked whenever DHCP is
used. And there are other examples that force similar dependencies. Using a
common NutConfig interface will remove some of these dependencies as all
modules would retrieve and store information independent of each other. But
not all, as one problem still remains; in the above DHCP example the actual
DNS addresses are delivered at a "random" time. The DNS would therefore have
to be notified that something actually has changed. I therefore propose a
global notification sub system which allows individual modules to subscribe
to and broadcast notifications between each other (see below). 


Suggested functions for the NutConfig addition:

void NutConfigSetMac(CONST char *adapter, u_byte *mac);
 int NutConfigGetMac(CONST char *adapter, u_byte *mac);

void NutConfigSetIpAddress(CONST char *adapter, u_long ip_addr);
 int NutConfigGetIpAddress(CONST char *adapter, u_long *ip_addr);

void NutConfigSetNetMask(CONST char *adapter, u_long ip_mask);
 int NutConfigGetNetMask(CONST char *adapter, u_long *ip_mask);

void NutConfigSetGateway(CONST char *adapter, u_long ip_gateway);
 int NutConfigGetGateway(CONST char *adapter, u_long *ip_gateway);

void NutConfigSetAssigedIpAddress(CONST char *adapter, u_long ip_assigned);
 int NutConfigGetAssigedIpAddress(CONST char *adapter, u_long *ip_assigned);

void NutConfigSetDns(CONST char *adapter, u_long ip_dns1, u_long ip_dns2);
 int NutConfigGetDns(CONST char *adapter, u_long *ip_dns1, u_long *ip_dns2);

void NutConfigSetNtp(CONST char *adapter, u_long ip_ntp);
 int NutConfigGetNtp(CONST char *adapter, u_long *ip_ntp);


Suggested functions for the notification interface:

HANDLE NutNofifySubscribe(void *filter <currently unused>, void (*callback)
(HANDLE, u_int identifier, void *arg1, void *arg2));

void NutNofifyUnsubscribe(HANDLE handle);

void NutNofifyBroadcast(u_int identifier, void *arg1, void *arg2);

Calling NutNotifyBroadcast(...) will call all subscribed callback functions
passing the given parameters to it. A callback function will be required to
keep processing to a minimum and return as soon as possible. The filter
parameter in NutNotifySubscribe(...) should be NULL if no filter is assigned
(and until we actual have implemented it).


So... that's it for now - looking forward to your comments!

Cu,
Michael