[PATCH 5/12] L2 network namespace: IPv4 routing

[Daniel Lezcano]

Dmitry Mishin wrote:
>  Make FIBs per-namespace and adds additional key (net namespace) to lookups in
>  routing cache.
> 
>  Signed-off-by: Dmitry Mishin <dim at openvz.org>
> 
> ---
>  include/linux/net_namespace.h |   12 ++++
>  include/net/flow.h            |    3 +
>  include/net/ip_fib.h          |   48 +++++++++++++---
>  net/core/fib_rules.c          |   43 ++++++++++++--
>  net/core/net_namespace.c      |    9 +++
>  net/ipv4/fib_frontend.c       |  121 +++++++++++++++++++++++++++++++++++-------
>  net/ipv4/fib_hash.c           |   13 +++-
>  net/ipv4/fib_rules.c          |   86 +++++++++++++++++++++++++----
>  net/ipv4/fib_semantics.c      |  100 +++++++++++++++++++++++-----------
>  net/ipv4/fib_trie.c           |   18 ++++--
>  net/ipv4/route.c              |   29 +++++++++-
>  11 files changed, 391 insertions(+), 91 deletions(-)
> 
> --- linux-2.6.19-rc6-mm2.orig/include/linux/net_namespace.h
> +++ linux-2.6.19-rc6-mm2/include/linux/net_namespace.h
> @@ -11,6 +11,18 @@ struct net_namespace {
>  	struct net_device	*dev_base_p, **dev_tail_p;
>  	struct net_device	*loopback_dev_p;
>  	struct pcpu_lstats	*pcpu_lstats_p;
> +#ifndef CONFIG_IP_MULTIPLE_TABLES
> +	struct fib_table	*fib4_local_table, *fib4_main_table;
> +#else
> +	struct list_head	fib_rules_ops_list;
> +	struct fib_rules_ops	*fib4_rules_ops;
> +#endif
> +	struct hlist_head	*fib4_tables;
> +	struct hlist_head	*fib4_hash, *fib4_laddrhash;
> +	unsigned		fib4_hash_size, fib4_info_cnt;
> +#ifdef CONFIG_IP_FIB_TRIE
> +	int			fib4_trie_last_dflt;
> +#endif
>  	unsigned int		hash;
>  };
>  
> --- linux-2.6.19-rc6-mm2.orig/include/net/flow.h
> +++ linux-2.6.19-rc6-mm2/include/net/flow.h
> @@ -82,6 +82,9 @@ struct flowi {
>  #define fl_mh_type	uli_u.mht.type
>  #endif
>  	__u32           secid;	/* used by xfrm; see secid.txt */
> +#ifdef CONFIG_NET_NS
> +	struct net_namespace *net_ns;
> +#endif
>  } __attribute__((__aligned__(BITS_PER_LONG/8)));
>  
>  #define FLOW_DIR_IN	0
> --- linux-2.6.19-rc6-mm2.orig/include/net/ip_fib.h
> +++ linux-2.6.19-rc6-mm2/include/net/ip_fib.h
> @@ -18,6 +18,7 @@
>  
>  #include <net/flow.h>
>  #include <linux/seq_file.h>
> +#include <linux/net_namespace.h>
>  #include <net/fib_rules.h>
>  
>  struct fib_config {
> @@ -171,14 +172,21 @@ struct fib_table {
>  
>  #ifndef CONFIG_IP_MULTIPLE_TABLES
>  
> -extern struct fib_table *ip_fib_local_table;
> -extern struct fib_table *ip_fib_main_table;
> +#ifndef CONFIG_NET_NS
> +extern struct fib_table *ip_fib_local_table_static;
> +extern struct fib_table *ip_fib_main_table_static;
> +#define ip_fib_local_table_ns()		ip_fib_local_table_static
> +#define ip_fib_main_table_ns()		ip_fib_main_table_static
> +#else
> +#define ip_fib_local_table_ns()		(current_net_ns->fib4_local_table)
> +#define ip_fib_main_table_ns()		(current_net_ns->fib4_main_table)
> +#endif

Why don't you use :
#ifndef CONFIG_NET_NS
extern struct fib_table *ip_fib_local_table
extern struct fib_table *ip_fib_main_table
#else
#define ip_fib_local_table (current_net_ns->fib4_local_table)
#define ip_fib_main_table (current_net_ns->fib4_main_table)
#endif

You don't need to replace all ip_fib_local_table by 
ip_fib_local_table_ns. It will reduce a lot the code impact, no ?