[Devel] Re: [patch 12/12] net namespace : Add broadcasting

[Herbert Poetzl]

On Fri, Jan 19, 2007 at 04:47:26PM +0100, dlezcano at fr.ibm.com wrote:
> From: Daniel Lezcano <dlezcano at fr.ibm.com>
> 
> Broadcast packets should be delivered to l2 and all l3 childs

hmm, really? shouldn't it only reach those which
actually have related addresses assigned?

best,
Herbert

> 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;
> 
> -- 
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