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Commit 246955fe authored by Robert Olsson's avatar Robert Olsson Committed by David S. Miller
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[NETLINK]: fib_lookup() via netlink 



Below is a more generic patch to do fib_lookup via netlink. For others 
we should say that we discussed this as a way to verify route selection.
It's also possible there are others uses for this.

In short the fist half of struct fib_result_nl is filled in by caller 
and netlink call fills in the other half and returns it.

In case anyone is interested there is a corresponding user app to compare 
the full routing table this was used to test implementation of the LC-trie. 

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f6e276ee

include/linux/netlink.h

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#define NETLINK_SELINUX		7	/* SELinux event notifications */

#define NETLINK_ARPD		8

#define NETLINK_AUDIT		9	/* auditing */

#define NETLINK_FIB_LOOKUP	10	

#define NETLINK_ROUTE6		11	/* af_inet6 route comm channel */

#define NETLINK_IP6_FW		13

#define NETLINK_DNRTMSG		14	/* DECnet routing messages */

include/net/ip_fib.h

+14 −0
Original line number Diff line number Diff line
@@ -109,6 +109,20 @@ struct fib_result { 
#endif

};



struct fib_result_nl {

	u32		fl_addr;   /* To be looked up*/ 

	u32		fl_fwmark; 

	unsigned char	fl_tos;

	unsigned char   fl_scope;

	unsigned char   tb_id_in;



	unsigned char   tb_id;      /* Results */

	unsigned char	prefixlen;

	unsigned char	nh_sel;

	unsigned char	type;

	unsigned char	scope;

	int             err;      

};



#ifdef CONFIG_IP_ROUTE_MULTIPATH

net/ipv4/fib_frontend.c

+55 −0
Original line number Diff line number Diff line
@@ -516,6 +516,60 @@ static void fib_del_ifaddr(struct in_ifaddr *ifa) 
#undef BRD1_OK

}



static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb )

{

	

	struct fib_result       res;

	struct flowi            fl = { .nl_u = { .ip4_u = { .daddr = frn->fl_addr, 

							    .fwmark = frn->fl_fwmark,

							    .tos = frn->fl_tos,

							    .scope = frn->fl_scope } } };

	if (tb) {

		local_bh_disable();



		frn->tb_id = tb->tb_id;

		frn->err = tb->tb_lookup(tb, &fl, &res);



		if (!frn->err) {

			frn->prefixlen = res.prefixlen;

			frn->nh_sel = res.nh_sel;

			frn->type = res.type;

			frn->scope = res.scope;

		}

		local_bh_enable();

	}

}



static void nl_fib_input(struct sock *sk, int len)

{

	struct sk_buff *skb = NULL;

        struct nlmsghdr *nlh = NULL;

	struct fib_result_nl *frn;

	int err;

	u32 pid;     

	struct fib_table *tb;

	

	skb = skb_recv_datagram(sk, 0, 0, &err);

	nlh = (struct nlmsghdr *)skb->data;

	

	frn = (struct fib_result_nl *) NLMSG_DATA(nlh);

	tb = fib_get_table(frn->tb_id_in);



	nl_fib_lookup(frn, tb);

	

	pid = nlh->nlmsg_pid;           /*pid of sending process */

	NETLINK_CB(skb).groups = 0;     /* not in mcast group */

	NETLINK_CB(skb).pid = 0;         /* from kernel */

	NETLINK_CB(skb).dst_pid = pid;

	NETLINK_CB(skb).dst_groups = 0;  /* unicast */

	netlink_unicast(sk, skb, pid, MSG_DONTWAIT);

}    



static void nl_fib_lookup_init(void)

{

      netlink_kernel_create(NETLINK_FIB_LOOKUP, nl_fib_input);

}



static void fib_disable_ip(struct net_device *dev, int force)

{

	if (fib_sync_down(0, dev, force))
@@ -604,6 +658,7 @@ void __init ip_fib_init(void) 


	register_netdevice_notifier(&fib_netdev_notifier);

	register_inetaddr_notifier(&fib_inetaddr_notifier);

	nl_fib_lookup_init();

}



EXPORT_SYMBOL(inet_addr_type);