[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/include/linux/netlink.h b/include/linux/netlink.h
index e38407a23d04bd0ac0706fd23774fc502cbda85f..561d4dc7583640cb28cb4fbbaf7a285ad4035da4 100644 (file)
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -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 */

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index e5a5f6b62f8800a537e67540b08c56f1c7e0b656..a4208a336ac09e58061af807e28a417f9ad1dd69 100644 (file)
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -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
 

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 563e7d61270612b64a5f67684c5eea1662b66a31..cd8e45ab95807116a18fe1649422766ef636da3c 100644 (file)
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -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);