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Date: Wed, 12 Dec 2012 18:24:38 +0100
From: Nicolas Dichtel <nicolas.dichtel@...nd.com>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, ebiederm@...ssion.com, aatteka@...ira.com,
Nicolas Dichtel <nicolas.dichtel@...nd.com>
Subject: [RFC PATCH net-next 2/5] netns: allow to dump netns with netlink
This patch adds the basic support of netlink for netns. The user can dump all
existing netns and get associated nsindex.
He also can get nsindex associated to a pid or fd.
To initialize genetlink family for netns, there is a problem of chicken and
eggs. genetlink init is done after init_net is created, hence when init_net is
created, we cannot call genl_register_family_with_ops(). It's why I put the
init part in genetlink module.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@...nd.com>
---
include/net/net_namespace.h | 1 +
include/uapi/linux/netns.h | 27 ++++++++
net/core/net_namespace.c | 157 ++++++++++++++++++++++++++++++++++++++++++++
net/netlink/genetlink.c | 4 ++
4 files changed, 189 insertions(+)
create mode 100644 include/uapi/linux/netns.h
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 5db7a1b..c373f2e 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -306,6 +306,7 @@ extern int register_pernet_subsys(struct pernet_operations *);
extern void unregister_pernet_subsys(struct pernet_operations *);
extern int register_pernet_device(struct pernet_operations *);
extern void unregister_pernet_device(struct pernet_operations *);
+extern int netns_genl_register(void);
struct ctl_table;
struct ctl_table_header;
diff --git a/include/uapi/linux/netns.h b/include/uapi/linux/netns.h
new file mode 100644
index 0000000..e1c1da3
--- /dev/null
+++ b/include/uapi/linux/netns.h
@@ -0,0 +1,27 @@
+#ifndef _UAPI_LINUX_NETNS_H_
+#define _UAPI_LINUX_NETNS_H_
+
+/* Generic netlink messages */
+
+#define NETNS_GENL_NAME "netns"
+#define NETNS_GENL_VERSION 0x1
+
+/* Commands */
+enum {
+ NETNS_CMD_NOOP,
+ NETNS_CMD_GET,
+ __NETNS_CMD_MAX,
+};
+#define NETNS_CMD_MAX (__NETNS_CMD_MAX - 1)
+
+/* Attributes */
+enum {
+ NETNSA_NONE,
+ NETNSA_NSINDEX,
+ NETNSA_PID,
+ NETNSA_FD,
+ __NETNSA_MAX,
+};
+#define NETNSA_MAX (__NETNSA_MAX - 1)
+
+#endif /* _UAPI_LINUX_NETNS_H_ */
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index f5267e4..2ae22b0 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -14,6 +14,8 @@
#include <linux/file.h>
#include <linux/export.h>
#include <linux/user_namespace.h>
+#include <linux/netns.h>
+#include <net/genetlink.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
@@ -397,6 +399,161 @@ struct net *get_net_ns_by_pid(pid_t pid)
}
EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
+static struct genl_family netns_nl_family = {
+ .id = GENL_ID_GENERATE,
+ .name = NETNS_GENL_NAME,
+ .version = NETNS_GENL_VERSION,
+ .hdrsize = 0,
+ .maxattr = NETNSA_MAX,
+ .netnsok = true,
+};
+
+static struct nla_policy netns_nl_policy[NETNSA_MAX + 1] = {
+ [NETNSA_NONE] = { .type = NLA_UNSPEC, },
+ [NETNSA_NSINDEX] = { .type = NLA_U32, },
+ [NETNSA_PID] = { .type = NLA_U32 },
+ [NETNSA_FD] = { .type = NLA_U32 },
+};
+
+static int netns_nl_get_size(void)
+{
+ return nla_total_size(sizeof(u32)) /* NETNSA_NSINDEX */
+ ;
+}
+
+static int netns_nl_cmd_noop(struct sk_buff *skb, struct genl_info *info)
+{
+ struct sk_buff *msg;
+ void *hdr;
+ int ret = -ENOBUFS;
+
+ msg = genlmsg_new(netns_nl_get_size(), GFP_KERNEL);
+ if (!msg) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
+ &netns_nl_family, 0, NETNS_CMD_NOOP);
+ if (!hdr) {
+ ret = -EMSGSIZE;
+ goto err_out;
+ }
+
+ genlmsg_end(msg, hdr);
+
+ return genlmsg_unicast(genl_info_net(info), msg, info->snd_portid);
+
+err_out:
+ nlmsg_free(msg);
+
+out:
+ return ret;
+}
+
+static int netns_nl_fill(struct sk_buff *skb, u32 portid, u32 seq, int flags,
+ int cmd, struct net *net)
+{
+ void *hdr;
+
+ hdr = genlmsg_put(skb, portid, seq, &netns_nl_family, flags, cmd);
+ if (!hdr)
+ return -EMSGSIZE;
+
+ if (nla_put_u32(skb, NETNSA_NSINDEX, net->nsindex))
+ goto nla_put_failure;
+
+ return genlmsg_end(skb, hdr);
+
+nla_put_failure:
+ genlmsg_cancel(skb, hdr);
+ return -EMSGSIZE;
+}
+
+static int netns_nl_cmd_get(struct sk_buff *skb, struct genl_info *info)
+{
+ struct net *net = genl_info_net(info);
+ struct sk_buff *msg;
+ int err = -ENOBUFS;
+
+ if (info->attrs[NETNSA_PID])
+ net = get_net_ns_by_pid(nla_get_u32(info->attrs[NETNSA_PID]));
+ else if (info->attrs[NETNSA_FD])
+ net = get_net_ns_by_fd(nla_get_u32(info->attrs[NETNSA_FD]));
+ else
+ get_net(net);
+
+ msg = genlmsg_new(netns_nl_get_size(), GFP_KERNEL);
+ if (!msg) {
+ err = -ENOMEM;
+ goto out;
+ }
+
+ err = netns_nl_fill(msg, info->snd_portid, info->snd_seq,
+ NLM_F_ACK, NETNS_CMD_GET, net);
+ if (err < 0)
+ goto err_out;
+
+ err = genlmsg_unicast(genl_info_net(info), msg, info->snd_portid);
+ goto out;
+
+err_out:
+ nlmsg_free(msg);
+
+out:
+ put_net(net);
+ return err;
+}
+
+static int netns_nl_cmd_dump(struct sk_buff *skb, struct netlink_callback *cb)
+{
+ int i = 0, s_i = cb->args[0];
+ struct net *net;
+
+ rtnl_lock();
+ for_each_net(net) {
+ if (i < s_i) {
+ i++;
+ continue;
+ }
+
+ if (netns_nl_fill(skb, NETLINK_CB(cb->skb).portid,
+ cb->nlh->nlmsg_seq, NLM_F_MULTI,
+ NETNS_CMD_GET, net) <= 0)
+ goto out;
+
+ i++;
+ }
+
+out:
+ cb->args[0] = i;
+ rtnl_unlock();
+
+ return skb->len;
+}
+
+static struct genl_ops netns_nl_ops[] = {
+ {
+ .cmd = NETNS_CMD_NOOP,
+ .policy = netns_nl_policy,
+ .doit = netns_nl_cmd_noop,
+ .flags = GENL_ADMIN_PERM,
+ },
+ {
+ .cmd = NETNS_CMD_GET,
+ .policy = netns_nl_policy,
+ .doit = netns_nl_cmd_get,
+ .dumpit = netns_nl_cmd_dump,
+ .flags = GENL_ADMIN_PERM,
+ },
+};
+
+int netns_genl_register(void)
+{
+ return genl_register_family_with_ops(&netns_nl_family, netns_nl_ops,
+ ARRAY_SIZE(netns_nl_ops));
+}
+
static int __init net_ns_init(void)
{
struct net_generic *ng;
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index f2aabb6..6d25ddb 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -963,6 +963,10 @@ static int __init genl_init(void)
if (err < 0)
goto problem;
+ err = netns_genl_register();
+ if (err < 0)
+ goto problem;
+
return 0;
problem:
--
1.8.0.1
--
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