[LLC]: add multicast support for datagrams

Allow mulitcast reception of datagrams (similar to UDP).
All sockets bound to the same SAP receive a clone.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/llc_if.h b/include/net/llc_if.h
index a05d04a..c608812 100644 (file)
--- a/include/net/llc_if.h
+++ b/include/net/llc_if.h
@@ -79,6 +79,10 @@ static inline int llc_addrany(const struct llc_addr *addr)
        return llc_mac_null(addr->mac) && !addr->lsap;
 }
 
+static inline int llc_mac_multicast(const u8 *mac)
+{
+       return is_multicast_ether_addr(mac);
+}
 /**
  *     llc_mac_match - determines if two mac addresses are the same
  *     @mac1: First mac address to compare.

diff --git a/net/llc/llc_sap.c b/net/llc/llc_sap.c
index 4029cee..20c4eb5 100644 (file)
--- a/net/llc/llc_sap.c
+++ b/net/llc/llc_sap.c
@@ -282,7 +282,7 @@ static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb)
  *     mac, and local sap. Returns pointer for socket found, %NULL otherwise.
  */
 static struct sock *llc_lookup_dgram(struct llc_sap *sap,
-                                    struct llc_addr *laddr)
+                                    const struct llc_addr *laddr)
 {
        struct sock *rc;
        struct hlist_node *node;
@@ -304,19 +304,62 @@ found:
        return rc;
 }
 
+/**
+ *     llc_sap_mcast - Deliver multicast PDU's to all matching datagram sockets.
+ *     @sap: SAP
+ *     @laddr: address of local LLC (MAC + SAP)
+ *
+ *     Search socket list of the SAP and finds connections with same sap.
+ *     Deliver clone to each.
+ */
+static void llc_sap_mcast(struct llc_sap *sap,
+                         const struct llc_addr *laddr,
+                         struct sk_buff *skb)
+{
+       struct sock *sk;
+       struct hlist_node *node;
+
+       read_lock_bh(&sap->sk_list.lock);
+       sk_for_each(sk, node, &sap->sk_list.list) {
+               struct llc_sock *llc = llc_sk(sk);
+               struct sk_buff *skb1;
+
+               if (sk->sk_type != SOCK_DGRAM)
+                       continue;
+
+               if (llc->laddr.lsap != laddr->lsap)
+                       continue;
+
+               skb1 = skb_clone(skb, GFP_ATOMIC);
+               if (!skb1)
+                       break;
+
+               sock_hold(sk);
+               skb_set_owner_r(skb1, sk);
+               llc_sap_rcv(sap, skb1);
+               sock_put(sk);
+       }
+       read_unlock_bh(&sap->sk_list.lock);
+}
+
+
 void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb)
 {
        struct llc_addr laddr;
-       struct sock *sk;
 
        llc_pdu_decode_da(skb, laddr.mac);
        llc_pdu_decode_dsap(skb, &laddr.lsap);
 
-       sk = llc_lookup_dgram(sap, &laddr);
-       if (sk) {
-               skb_set_owner_r(skb, sk);
-               llc_sap_rcv(sap, skb);
-               sock_put(sk);
-       } else
+       if (llc_mac_multicast(laddr.mac)) {
+               llc_sap_mcast(sap, &laddr, skb);
                kfree_skb(skb);
+       } else {
+               struct sock *sk = llc_lookup_dgram(sap, &laddr);
+               if (sk) {
+                       skb_set_owner_r(skb, sk);
+                       llc_sap_rcv(sap, skb);
+                       sock_put(sk);
+               } else
+                       kfree_skb(skb);
+       }
 }