sysctl command with struct

[Pham Viet Ha]

Hi all,

I am writing a code using sysctl to manipulate a kernel variable. The variable is a data structure with two fields, protocol number (uint16_t) and description (char *).

I have some difficulties with sysctl command to pass both protocol number and description at a time to the kernel. I used CTLTYPE_OPAQUE in SYSCTL_ADD_PROC call, then I used sysctl_handle_opaque to read data. 

It does not work correctly. I don't know how what is the format I have to use when I type in "sysctl ..." at the prompt. 

struct protodesc { 
uint16_t protonumber; 
char description[256];
}