From: Daniel Lezcano <[EMAIL PROTECTED]>
When a packet is outgoing, the namespace source is stored
into the skbuff. Because it is the loopback address, the
source == destination, so when the packet is incoming, it
has already the namespace destination set into the packet.
Signed-off-by: Daniel Lezcano <[EMAIL PROTECTED]>
---
include/linux/net_namespace.h | 13 +++++++++++--
include/linux/skbuff.h | 5 ++++-
net/core/net_namespace.c | 32 +++++++++++++++++++++++++++-----
net/ipv4/ip_input.c | 2 +-
net/ipv4/ip_output.c | 1 +
5 files changed, 44 insertions(+), 9 deletions(-)
Index: 2.6.20-rc4-mm1/include/linux/skbuff.h
===================================================================
--- 2.6.20-rc4-mm1.orig/include/linux/skbuff.h
+++ 2.6.20-rc4-mm1/include/linux/skbuff.h
@@ -225,6 +225,7 @@
* @dma_cookie: a cookie to one of several possible DMA operations
* done by skb DMA functions
* @secmark: security marking
+ * @net_ns: namespace destination
*/
struct sk_buff {
@@ -309,7 +310,9 @@
#ifdef CONFIG_NETWORK_SECMARK
__u32 secmark;
#endif
-
+#ifdef CONFIG_NET_NS
+ struct net_namespace *net_ns;
+#endif
__u32 mark;
/* These elements must be at the end, see alloc_skb() for details. */
Index: 2.6.20-rc4-mm1/net/ipv4/ip_input.c
===================================================================
--- 2.6.20-rc4-mm1.orig/net/ipv4/ip_input.c
+++ 2.6.20-rc4-mm1/net/ipv4/ip_input.c
@@ -396,7 +396,7 @@
iph = skb->nh.iph;
- dst_net_ns = net_ns_find_from_dest_addr(iph->daddr);
+ dst_net_ns = net_ns_find_from_dest_addr(skb);
if (dst_net_ns && !net_ns_match(net_ns, dst_net_ns))
push_net_ns(dst_net_ns);
/*
Index: 2.6.20-rc4-mm1/net/ipv4/ip_output.c
===================================================================
--- 2.6.20-rc4-mm1.orig/net/ipv4/ip_output.c
+++ 2.6.20-rc4-mm1/net/ipv4/ip_output.c
@@ -272,6 +272,7 @@
IP_INC_STATS(IPSTATS_MIB_OUTREQUESTS);
+ net_ns_tag_sk_buff(skb);
skb->dev = dev;
skb->protocol = htons(ETH_P_IP);
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
@@ -8,6 +8,7 @@
#include <linux/types.h>
struct in_ifaddr;
+struct sk_buff;
struct net_namespace {
struct kref kref;
@@ -101,10 +102,13 @@
extern __be32 net_ns_select_source_address(const struct net_device *dev,
u32 dst, int scope);
-extern struct net_namespace *net_ns_find_from_dest_addr(u32 daddr);
+extern struct net_namespace
+*net_ns_find_from_dest_addr(const struct sk_buff *skb);
extern int net_ns_ifa_is_visible(const struct in_ifaddr *ifa);
+extern void net_ns_tag_sk_buff(struct sk_buff *skb);
+
#define SELECT_SRC_ADDR net_ns_select_source_address
#else /* CONFIG_NET_NS */
@@ -173,7 +177,8 @@
return 0;
}
-static inline struct net_namespace *net_ns_find_from_dest_addr(u32 daddr)
+static inline struct net_namespace
+*net_ns_find_from_dest_addr(const struct sk_buff *skb)
{
return NULL;
}
@@ -183,6 +188,10 @@
return 1;
}
+static inline void net_ns_tag_sk_buff(struct sk_buff *skb)
+{
+ ;
+}
#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
@@ -13,6 +13,9 @@
#include <linux/in.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
+#include <linux/skbuff.h>
+#include <linux/ip.h>
+
#include <net/ip_fib.h>
struct net_namespace init_net_ns = {
@@ -389,18 +392,25 @@
/*
* This function finds the network namespace destination deduced from
* the destination address. The network namespace is retrieved from
- * the ifaddr owned by a network namespace
- * @daddr : destination
+ * the ifaddr owned by a network namespace. If the packet is for the
+ * loopback address so we assume the destination address is already filled
+ * by the sender which is the same as the receiver.
+ * @skb : the packet to be delivered
* Returns : the network namespace destination or NULL if not found
*/
-struct net_namespace *net_ns_find_from_dest_addr(u32 daddr)
+struct net_namespace *net_ns_find_from_dest_addr(const struct sk_buff *skb)
{
struct net_namespace *net_ns = NULL;
struct net_device *dev;
struct in_device *in_dev;
+ struct iphdr *iph;
+ __be32 daddr;
+
+ iph = skb->nh.iph;
+ daddr = iph->daddr;
- if (LOOPBACK(daddr))
- return current_net_ns;
+ if (LOOPBACK(daddr))
+ return skb->net_ns;
read_lock(&dev_base_lock);
rcu_read_lock();
@@ -442,4 +452,16 @@
return 0;
}
+/*
+ * This function allows to isolation the loopback. Because we are
+ * using the 127.0.0.1, we assume the source network namespace is
+ * the same as the destination network namespace. So setting the
+ * source, we have directly the destination when receiving the packet
+ * @skb : the packet to be tagged with the network namespace
+ */
+void net_ns_tag_sk_buff(struct sk_buff *skb)
+{
+ struct net_namespace *net_ns = current_net_ns;
+ skb->net_ns = net_ns;
+}
#endif /* CONFIG_NET_NS */
--
-
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