[patch 12/12] net namespace : Add broadcasting

[dlezcano at fr.ibm.com]

From: Daniel Lezcano <dlezcano at fr.ibm.com>

Broadcast packets should be delivered to l2 and all l3 childs

Signed-off-by: Daniel Lezcano <dlezcano at fr.ibm.com>

---
 include/linux/net_namespace.h |   11 +++++++++++
 net/core/net_namespace.c      |   27 +++++++++++++++++++++++++++
 net/ipv4/udp.c                |    3 ++-
 3 files changed, 40 insertions(+), 1 deletion(-)

Index: 2.6.20-rc4-mm1/include/linux/net_namespace.h
===================================================================
--- 2.6.20-rc4-mm1.orig/include/linux/net_namespace.h
+++ 2.6.20-rc4-mm1/include/linux/net_namespace.h
@@ -9,6 +9,7 @@
 
 struct in_ifaddr;
 struct sk_buff;
+struct sock;
 
 struct net_namespace {
 	struct kref		kref;
@@ -109,6 +110,9 @@
 
 extern void net_ns_tag_sk_buff(struct sk_buff *skb);
 
+extern int net_ns_sock_is_visible(const struct sock *sk,
+				  const struct net_namespace *net_ns);
+
 #define SELECT_SRC_ADDR net_ns_select_source_address
 
 #else /* CONFIG_NET_NS */
@@ -192,6 +196,13 @@
 {
 	;
 }
+
+static inline int net_ns_sock_is_visible(const struct sock *sk,
+ 					 const struct net_namespace *net_ns)
+{
+ 	return 1;
+}
+
 #define SELECT_SRC_ADDR inet_select_addr
 
 #endif /* !CONFIG_NET_NS */
Index: 2.6.20-rc4-mm1/net/core/net_namespace.c
===================================================================
--- 2.6.20-rc4-mm1.orig/net/core/net_namespace.c
+++ 2.6.20-rc4-mm1/net/core/net_namespace.c
@@ -17,6 +17,7 @@
 #include <linux/ip.h>
 
 #include <net/ip_fib.h>
+#include <net/sock.h>
 
 struct net_namespace init_net_ns = {
 	.kref = {
@@ -464,4 +465,30 @@
 	struct net_namespace *net_ns = current_net_ns;
 	skb->net_ns = net_ns;
 }
+
+/*
+ * This function checks if the socket is visible from the specified
+ * namespace. This is needed to ensure the broadcast and the multicast
+ * for multiple network namespace l2 and l3 to have the packets to be
+ * delivered. If we have a l3 namespace and its parent (l2 namespace)
+ * listening on a broadcast address, we should deliver the packet to
+ * both. That is done by the udp_v4_mcast_next function. But we should
+ * find a common point between sockets which are relatives to a
+ * namespace.  The common point is they have the same parent in case
+ * of l3 network namespace.
+ * @sk : the socket to be checked
+ * @net_ns : the receiving network namespace
+ * Returns: 1 if the socket is visible by the namespace, 0 otherwise.
+ */
+int net_ns_sock_is_visible(const struct sock *sk,
+			   const struct net_namespace *net_ns)
+{
+	if (net_ns->level == NET_NS_LEVEL3)
+		net_ns = net_ns->parent;
+
+	if (sk->sk_net_ns->level == NET_NS_LEVEL3)
+		return sk->sk_net_ns->parent == net_ns;
+	else
+		return sk->sk_net_ns == net_ns;
+}
 #endif /* CONFIG_NET_NS */
Index: 2.6.20-rc4-mm1/net/ipv4/udp.c
===================================================================
--- 2.6.20-rc4-mm1.orig/net/ipv4/udp.c
+++ 2.6.20-rc4-mm1/net/ipv4/udp.c
@@ -309,9 +309,10 @@
 		    (inet->dport != rmt_port && inet->dport)		||
 		    (inet->rcv_saddr && inet->rcv_saddr != loc_addr)	||
 		    ipv6_only_sock(s)					||
-		    !net_ns_match(sk->sk_net_ns, ns)			||
 		    (s->sk_bound_dev_if && s->sk_bound_dev_if != dif))
 			continue;
+		if (!net_ns_sock_is_visible(sk, ns))
+			continue;
 		if (!ip_mc_sf_allow(s, loc_addr, rmt_addr, dif))
 			continue;
 		goto found;

--