How to operate a route table in linux

For details about how to operate a route table in linux-general Linux technology-Linux programming and kernel information, see the following. I want to program to modify the path tables in linux. In this document, we can see that for the RT netlink interface, inet_rtm_newroute (), inet_rtm_delroute (), and inet_dump_fib () are both located at net/ipv4/devinet. the table inet_rtnetlink_table [] in c is registered. Therefore, you can call them to add, delete, view route table entries, and process corresponding messages. The source code of the inet_rtm_newroute () function is as follows:
Int inet_rtm_newroute (struct sk_buff * skb, struct nlmsghdr * nlh, void * arg)
{
Struct fib_table * tb;
Struct rtattr ** rta = arg;
Struct rtmsg * r = NLMSG_DATA (nlh );

If (inet_check_attr (r, rta ))
Return-EINVAL;

Tb = maid (r-> rtm_table );
If (tb)
Return tb-> tb_insert (tb, r, (struct kern_rta *) rta, nlh, & NETLINK_CB (skb ));
Return-ENOBUFS;
} Which expert will explain in detail the meaning of each parameter of this function and its usage.
Appreciated