llc: add support for SO_BINDTODEVICE

Using bind(MAC address) with LLC sockets has O(n) complexity, where n
is the number of interfaces. To overcome this, we add support for
SO_BINDTODEVICE which drops the complexity to O(1).

Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 27 insertions, 2 deletions

diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c
index ac691fe08076..c4d1a1da813c 100644
--- a/net/llc/af_llc.c
+++ b/net/llc/af_llc.c
@@ -259,7 +259,14 @@ static int llc_ui_autobind(struct socket *sock, struct sockaddr_llc *addr)
         if (!sock_flag(sk, SOCK_ZAPPED))
                 goto out;
         rc = -ENODEV;
-        llc->dev = dev_getfirstbyhwtype(&init_net, addr->sllc_arphrd);
+        if (sk->sk_bound_dev_if) {
+                llc->dev = dev_get_by_index(&init_net, sk->sk_bound_dev_if);
+                if (llc->dev && addr->sllc_arphrd != llc->dev->type) {
+                        dev_put(llc->dev);
+                        llc->dev = NULL;
+                }
+        } else
+                llc->dev = dev_getfirstbyhwtype(&init_net, addr->sllc_arphrd);
         if (!llc->dev)
                 goto out;
         rc = -EUSERS;
@@ -310,7 +317,25 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
                 goto out;
         rc = -ENODEV;
         rtnl_lock();
-        llc->dev = dev_getbyhwaddr(&init_net, addr->sllc_arphrd, addr->sllc_mac);
+        if (sk->sk_bound_dev_if) {
+                llc->dev = dev_get_by_index(&init_net, sk->sk_bound_dev_if);
+                if (llc->dev) {
+                        if (!addr->sllc_arphrd)
+                                addr->sllc_arphrd = llc->dev->type;
+                        if (llc_mac_null(addr->sllc_mac))
+                                memcpy(addr->sllc_mac, llc->dev->dev_addr,
+                                       IFHWADDRLEN);
+                        if (addr->sllc_arphrd != llc->dev->type ||
+                            !llc_mac_match(addr->sllc_mac,
+                                           llc->dev->dev_addr)) {
+                                rc = -EINVAL;
+                                dev_put(llc->dev);
+                                llc->dev = NULL;
+                        }
+                }
+        } else
+                llc->dev = dev_getbyhwaddr(&init_net, addr->sllc_arphrd,
+                                           addr->sllc_mac);
         rtnl_unlock();
         if (!llc->dev)
                 goto out;