[Devel] [PATCH 10/12] L2 network namespace: playing with pass-through device
Dmitry Mishin
dim at openvz.org
Wed Dec 6 14:29:39 PST 2006
Temporary code to debug and play with pass-through device.
Create device pair by
modprobe veth
echo 'add veth1 0:1:2:3:4:1 eth0 0:1:2:3:4:2' >/proc/net/veth_ctl
and your shell will appear into a new namespace with `eth0' device.
Configure device in this namespace
ip l s eth0 up
ip a a 1.2.3.4/24 dev eth0
and in the root namespace
ip l s veth1 up
ip a a 1.2.3.1/24 dev veth1
to establish a communication channel between root namespace and the newly
created one.
Code is done by Andrey Savochkin and ported by me over Cedric'c patchset
Signed-off-by: Dmitry Mishin <dim at openvz.org>
---
drivers/net/veth.c | 121 ++++++++++++++++++++++++++++++++++++++++++
fs/proc/array.c | 8 ++
include/linux/net_namespace.h | 10 +++
kernel/nsproxy.c | 2
net/core/net_namespace.c | 28 +++++++++
5 files changed, 168 insertions(+), 1 deletion(-)
--- linux-2.6.19-rc6-mm2.orig/drivers/net/veth.c
+++ linux-2.6.19-rc6-mm2/drivers/net/veth.c
@@ -12,6 +12,7 @@
#include <linux/etherdevice.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
+#include <linux/syscalls.h>
#include <net/dst.h>
#include <net/xfrm.h>
@@ -245,6 +246,123 @@ void veth_entry_del_all(void)
/* ------------------------------------------------------------------- *
*
+ * Temporary interface to create veth devices
+ *
+ * ------------------------------------------------------------------- */
+
+#ifdef CONFIG_PROC_FS
+
+static int veth_debug_open(struct inode *inode, struct file *file)
+{
+ return 0;
+}
+
+static char *parse_addr(char *s, char *addr)
+{
+ int i, v;
+
+ for (i = 0; i < ETH_ALEN; i++) {
+ if (!isxdigit(*s))
+ return NULL;
+ *addr = 0;
+ v = isdigit(*s) ? *s - '0' : toupper(*s) - 'A' + 10;
+ s++;
+ if (isxdigit(*s)) {
+ *addr += v << 16;
+ v = isdigit(*s) ? *s - '0' : toupper(*s) - 'A' + 10;
+ s++;
+ }
+ *addr++ += v;
+ if (i < ETH_ALEN - 1 && ispunct(*s))
+ s++;
+ }
+ return s;
+}
+
+static ssize_t veth_debug_write(struct file *file, const char __user *user_buf,
+ size_t size, loff_t *ppos)
+{
+ char buf[128], *s, *parent_name, *child_name;
+ char parent_addr[ETH_ALEN], child_addr[ETH_ALEN];
+ struct net_namespace *parent_ns, *child_ns;
+ int err;
+
+ s = buf;
+ err = -EINVAL;
+ if (size >= sizeof(buf))
+ goto out;
+ err = -EFAULT;
+ if (copy_from_user(buf, user_buf, size))
+ goto out;
+ buf[size] = 0;
+
+ err = -EBADRQC;
+ if (!strncmp(buf, "add ", 4)) {
+ parent_name = buf + 4;
+ if ((s = strchr(parent_name, ' ')) == NULL)
+ goto out;
+ *s = 0;
+ if ((s = parse_addr(s + 1, parent_addr)) == NULL)
+ goto out;
+ if (!*s)
+ goto out;
+ child_name = s + 1;
+ if ((s = strchr(child_name, ' ')) == NULL)
+ goto out;
+ *s = 0;
+ if ((s = parse_addr(s + 1, child_addr)) == NULL)
+ goto out;
+
+ get_net_ns(current_net_ns);
+ parent_ns = current_net_ns;
+ if (*s == ' ') {
+ unsigned int id;
+ id = simple_strtoul(s + 1, &s, 0);
+ err = sys_bind_ns(id, NS_ALL);
+ } else
+ err = sys_unshare_ns(NS_NET);
+ if (err)
+ goto out;
+ /* after bind_ns() or unshare_ns() namespace is changed */
+ get_net_ns(current_net_ns);
+ child_ns = current_net_ns;
+ err = veth_entry_add(parent_name, parent_addr, parent_ns,
+ child_name, child_addr, child_ns);
+ if (err) {
+ put_net_ns(child_ns);
+ put_net_ns(parent_ns);
+ } else
+ err = size;
+ }
+out:
+ return err;
+}
+
+static struct file_operations veth_debug_ops = {
+ .open = &veth_debug_open,
+ .write = &veth_debug_write,
+};
+
+static int veth_debug_create(void)
+{
+ proc_net_fops_create("veth_ctl", 0200, &veth_debug_ops);
+ return 0;
+}
+
+static void veth_debug_remove(void)
+{
+ proc_net_remove("veth_ctl");
+}
+
+#else
+
+static int veth_debug_create(void) { return -1; }
+static void veth_debug_remove(void) { }
+
+#endif
+
+/* ------------------------------------------------------------------- *
+ *
* Information in proc
*
* ------------------------------------------------------------------- */
@@ -304,12 +422,15 @@ static inline void veth_proc_remove(void
int __init veth_init(void)
{
+ if (veth_debug_create())
+ return -EINVAL;
veth_proc_create();
return 0;
}
void __exit veth_exit(void)
{
+ veth_debug_remove();
veth_proc_remove();
veth_entry_del_all();
}
--- linux-2.6.19-rc6-mm2.orig/fs/proc/array.c
+++ linux-2.6.19-rc6-mm2/fs/proc/array.c
@@ -72,6 +72,7 @@
#include <linux/highmem.h>
#include <linux/file.h>
#include <linux/times.h>
+#include <linux/net_namespace.h>
#include <linux/cpuset.h>
#include <linux/rcupdate.h>
#include <linux/delayacct.h>
@@ -198,6 +199,13 @@ static inline char * task_state(struct t
put_group_info(group_info);
buffer += sprintf(buffer, "\n");
+
+#ifdef CONFIG_NET_NS
+ if (p == current)
+ buffer += sprintf(buffer, "NetContext: %u\n",
+ p->nsproxy->net_ns->id);
+#endif
+
return buffer;
}
--- linux-2.6.19-rc6-mm2.orig/include/linux/net_namespace.h
+++ linux-2.6.19-rc6-mm2/include/linux/net_namespace.h
@@ -24,6 +24,9 @@ struct net_namespace {
int fib4_trie_last_dflt;
#endif
unsigned int hash;
+ struct net_namespace *parent;
+ struct list_head child_list, sibling_list;
+ unsigned int id;
};
extern struct net_namespace init_net_ns;
@@ -69,6 +72,8 @@ static inline void pop_net_ns(struct net
#define net_ns_hash(ns) ((ns)->hash)
+extern struct net_namespace *find_net_ns(unsigned int id);
+
#else /* CONFIG_NET_NS */
#define INIT_NET_NS(net_ns)
@@ -110,6 +115,11 @@ static inline void pop_net_ns(struct net
#define net_ns_hash(ns) (0)
+static inline struct net_namespace *find_net_ns(unsigned int id)
+{
+ return NULL;
+}
+
#endif /* !CONFIG_NET_NS */
#endif /* _LINUX_NET_NAMESPACE_H */
--- linux-2.6.19-rc6-mm2.orig/kernel/nsproxy.c
+++ linux-2.6.19-rc6-mm2/kernel/nsproxy.c
@@ -430,6 +430,7 @@ unlock:
put_nsproxy(ns);
return ret;
}
+EXPORT_SYMBOL(sys_bind_ns);
/*
* sys_unshare_ns - unshare one or more of namespaces which were
@@ -573,6 +574,7 @@ bad_unshare_ns_cleanup_fs:
bad_unshare_ns_out:
return err;
}
+EXPORT_SYMBOL(sys_unshare_ns);
static int __init nshash_init(void)
{
--- linux-2.6.19-rc6-mm2.orig/net/core/net_namespace.c
+++ linux-2.6.19-rc6-mm2/net/core/net_namespace.c
@@ -13,6 +13,8 @@
#include <linux/netdevice.h>
#include <net/ip_fib.h>
+static spinlock_t net_ns_list_lock = SPIN_LOCK_UNLOCKED;
+
struct net_namespace init_net_ns = {
.kref = {
.refcount = ATOMIC_INIT(2),
@@ -22,6 +24,8 @@ struct net_namespace init_net_ns = {
.dev_tail_p = &init_net_ns.dev_base_p,
.loopback_dev_p = NULL,
.pcpu_lstats_p = NULL,
+ .child_list = LIST_HEAD_INIT(init_net_ns.child_list),
+ .sibling_list = LIST_HEAD_INIT(init_net_ns.sibling_list),
};
#ifdef CONFIG_NET_NS
@@ -44,6 +48,12 @@ static struct net_namespace *clone_net_n
ns->dev_base_p = NULL;
ns->dev_tail_p = &ns->dev_base_p;
ns->hash = net_random();
+ INIT_LIST_HEAD(&ns->child_list);
+ spin_lock_irq(&net_ns_list_lock);
+ get_net_ns(old_ns);
+ ns->parent = old_ns;
+ list_add_tail(&ns->sibling_list, &old_ns->child_list);
+ spin_unlock_irq(&net_ns_list_lock);
#ifdef CONFIG_IP_MULTIPLE_TABLES
INIT_LIST_HEAD(&ns->fib_rules_ops_list);
@@ -52,6 +62,8 @@ static struct net_namespace *clone_net_n
goto out_fib4;
if (loopback_init(ns))
goto out_loopback;
+ printk(KERN_DEBUG "NET_NS: created new netcontext %p for %s "
+ "(pid=%d)\n", ns, current->comm, current->tgid);
return ns;
out_loopback:
@@ -95,8 +107,20 @@ int copy_net_ns(int flags, struct task_s
void free_net_ns(struct kref *kref)
{
struct net_namespace *ns;
+ unsigned long flags;
+ /* taking lock after atomic_dec_and_test is racy */
+ spin_lock_irqsave(&net_ns_list_lock, flags);
ns = container_of(kref, struct net_namespace, kref);
+ if (atomic_read(&ns->kref.refcount) ||
+ list_empty(&ns->sibling_list)) {
+ spin_unlock_irqrestore(&net_ns_list_lock, flags);
+ return;
+ }
+ list_del_init(&ns->sibling_list);
+ spin_unlock_irqrestore(&net_ns_list_lock, flags);
+ put_net_ns(ns->parent);
+
unregister_netdev(ns->loopback_dev_p);
if (ns->dev_base_p != NULL) {
printk("NET_NS: BUG: namespace %p has devices! ref %d\n",
@@ -104,8 +128,10 @@ void free_net_ns(struct kref *kref)
return;
}
ip_fib_struct_cleanup();
+ printk(KERN_DEBUG "NET_NS: net namespace %p (%u) destroyed\n",
+ ns, ns->id);
kfree(ns);
}
+/* because of put_net_ns() */
EXPORT_SYMBOL(free_net_ns);
-
#endif /* CONFIG_NET_NS */
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