[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: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 563e7d6..cd8e45a 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -516,6 +516,60 @@
#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 @@
register_netdevice_notifier(&fib_netdev_notifier);
register_inetaddr_notifier(&fib_inetaddr_notifier);
+ nl_fib_lookup_init();
}
EXPORT_SYMBOL(inet_addr_type);