Merge branch 'netns-next'

Nicolas Dichtel says:

====================
netns: enhance netlink interface for nsid

The first patch is a small cleanup. The second patch implements notifications
for netns id events. And the last one allows to dump existing netns id from
userland.

iproute2 patches are available, I can send them on demand.

v2: drop the first patch (the fix is now in net-next)
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 97 insertions, 10 deletions

diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
index bea910f924dd..974db03f7b1a 100644
--- a/include/uapi/linux/rtnetlink.h
+++ b/include/uapi/linux/rtnetlink.h
@@ -134,6 +134,8 @@ enum {
 
         RTM_NEWNSID = 88,
 #define RTM_NEWNSID RTM_NEWNSID
+        RTM_DELNSID = 89,
+#define RTM_DELNSID RTM_DELNSID
         RTM_GETNSID = 90,
 #define RTM_GETNSID RTM_GETNSID
 
@@ -635,6 +637,8 @@ enum rtnetlink_groups {
 #define RTNLGRP_MDB             RTNLGRP_MDB
         RTNLGRP_MPLS_ROUTE,
 #define RTNLGRP_MPLS_ROUTE      RTNLGRP_MPLS_ROUTE
+        RTNLGRP_NSID,
+#define RTNLGRP_NSID            RTNLGRP_NSID
         __RTNLGRP_MAX
 };
 #define RTNLGRP_MAX     (__RTNLGRP_MAX - 1)
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index e7345d9031df..a3abb719221f 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -148,9 +148,11 @@ static void ops_free_list(const struct pernet_operations *ops,
         }
 }
 
+static void rtnl_net_notifyid(struct net *net, struct net *peer, int cmd,
+                              int id);
 static int alloc_netid(struct net *net, struct net *peer, int reqid)
 {
-        int min = 0, max = 0;
+        int min = 0, max = 0, id;
 
         ASSERT_RTNL();
 
@@ -159,7 +161,11 @@ static int alloc_netid(struct net *net, struct net *peer, int reqid)
                 max = reqid + 1;
         }
 
-        return idr_alloc(&net->netns_ids, peer, min, max, GFP_KERNEL);
+        id = idr_alloc(&net->netns_ids, peer, min, max, GFP_KERNEL);
+        if (id >= 0)
+                rtnl_net_notifyid(net, peer, RTM_NEWNSID, id);
+
+        return id;
 }
 
 /* This function is used by idr_for_each(). If net is equal to peer, the
@@ -359,8 +365,10 @@ static void cleanup_net(struct work_struct *work)
                 for_each_net(tmp) {
                         int id = __peernet2id(tmp, net, false);
 
-                        if (id >= 0)
+                        if (id >= 0) {
+                                rtnl_net_notifyid(tmp, net, RTM_DELNSID, id);
                                 idr_remove(&tmp->netns_ids, id);
+                        }
                 }
                 idr_destroy(&net->netns_ids);
 
@@ -531,7 +539,8 @@ static int rtnl_net_get_size(void)
 }
 
 static int rtnl_net_fill(struct sk_buff *skb, u32 portid, u32 seq, int flags,
-                         int cmd, struct net *net, struct net *peer)
+                         int cmd, struct net *net, struct net *peer,
+                         int nsid)
 {
         struct nlmsghdr *nlh;
         struct rtgenmsg *rth;
@@ -546,9 +555,13 @@ static int rtnl_net_fill(struct sk_buff *skb, u32 portid, u32 seq, int flags,
         rth = nlmsg_data(nlh);
         rth->rtgen_family = AF_UNSPEC;
 
-        id = __peernet2id(net, peer, false);
-        if  (id < 0)
-                id = NETNSA_NSID_NOT_ASSIGNED;
+        if (nsid >= 0) {
+                id = nsid;
+        } else {
+                id = __peernet2id(net, peer, false);
+                if  (id < 0)
+                        id = NETNSA_NSID_NOT_ASSIGNED;
+        }
         if (nla_put_s32(skb, NETNSA_NSID, id))
                 goto nla_put_failure;
 
@@ -565,8 +578,8 @@ static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh)
         struct net *net = sock_net(skb->sk);
         struct nlattr *tb[NETNSA_MAX + 1];
         struct sk_buff *msg;
-        int err = -ENOBUFS;
         struct net *peer;
+        int err;
 
         err = nlmsg_parse(nlh, sizeof(struct rtgenmsg), tb, NETNSA_MAX,
                           rtnl_net_policy);
@@ -589,7 +602,7 @@ static int rtnl_net_getid(struct sk_buff *skb, struct nlmsghdr *nlh)
         }
 
         err = rtnl_net_fill(msg, NETLINK_CB(skb).portid, nlh->nlmsg_seq, 0,
-                            RTM_GETNSID, net, peer);
+                            RTM_GETNSID, net, peer, -1);
         if (err < 0)
                 goto err_out;
 
@@ -603,6 +616,75 @@ out:
         return err;
 }
 
+struct rtnl_net_dump_cb {
+        struct net *net;
+        struct sk_buff *skb;
+        struct netlink_callback *cb;
+        int idx;
+        int s_idx;
+};
+
+static int rtnl_net_dumpid_one(int id, void *peer, void *data)
+{
+        struct rtnl_net_dump_cb *net_cb = (struct rtnl_net_dump_cb *)data;
+        int ret;
+
+        if (net_cb->idx < net_cb->s_idx)
+                goto cont;
+
+        ret = rtnl_net_fill(net_cb->skb, NETLINK_CB(net_cb->cb->skb).portid,
+                            net_cb->cb->nlh->nlmsg_seq, NLM_F_MULTI,
+                            RTM_NEWNSID, net_cb->net, peer, id);
+        if (ret < 0)
+                return ret;
+
+cont:
+        net_cb->idx++;
+        return 0;
+}
+
+static int rtnl_net_dumpid(struct sk_buff *skb, struct netlink_callback *cb)
+{
+        struct net *net = sock_net(skb->sk);
+        struct rtnl_net_dump_cb net_cb = {
+                .net = net,
+                .skb = skb,
+                .cb = cb,
+                .idx = 0,
+                .s_idx = cb->args[0],
+        };
+
+        ASSERT_RTNL();
+
+        idr_for_each(&net->netns_ids, rtnl_net_dumpid_one, &net_cb);
+
+        cb->args[0] = net_cb.idx;
+        return skb->len;
+}
+
+static void rtnl_net_notifyid(struct net *net, struct net *peer, int cmd,
+                              int id)
+{
+        struct sk_buff *msg;
+        int err = -ENOMEM;
+
+        msg = nlmsg_new(rtnl_net_get_size(), GFP_KERNEL);
+        if (!msg)
+                goto out;
+
+        err = rtnl_net_fill(msg, 0, 0, 0, cmd, net, peer, id);
+        if (err < 0)
+                goto err_out;
+
+        rtnl_notify(msg, net, 0, RTNLGRP_NSID, NULL, 0);
+        return;
+
+err_out:
+        nlmsg_free(msg);
+out:
+        rtnl_set_sk_err(net, RTNLGRP_NSID, err);
+}
+
 static int __init net_ns_init(void)
 {
         struct net_generic *ng;
@@ -637,7 +719,8 @@ static int __init net_ns_init(void)
         register_pernet_subsys(&net_ns_ops);
 
         rtnl_register(PF_UNSPEC, RTM_NEWNSID, rtnl_net_newid, NULL, NULL);
-        rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, NULL, NULL);
+        rtnl_register(PF_UNSPEC, RTM_GETNSID, rtnl_net_getid, rtnl_net_dumpid,
+                      NULL);
 
         return 0;
 }