tipc: implement socket diagnostics for AF_TIPC

This commit adds socket diagnostics capability for AF_TIPC in netlink
family NETLINK_SOCK_DIAG in a new kernel module (diag.ko).

The following are key design considerations:
- config TIPC_DIAG has default y, like INET_DIAG.
- only requests with flag NLM_F_DUMP is supported (dump all).
- tipc_sock_diag_req message is introduced to send filter parameters.
- the response attributes are of TLV, some nested.

To avoid exposing data structures between diag and tipc modules and
avoid code duplication, the following additions are required:
- export tipc_nl_sk_walk function to reuse socket iterator.
- export tipc_sk_fill_sock_diag to fill the tipc diag attributes.
- create a sock_diag response message in __tipc_add_sock_diag defined
  in diag.c and use the above exported tipc_sk_fill_sock_diag
  to fill response.

Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: GhantaKrishnamurthy MohanKrishna <mohan.krishna.ghanta.krishnamurthy@ericsson.com>
Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 67 insertions, 5 deletions

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 35ac0f5b9529..07559ce4b8ba 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -3213,10 +3213,10 @@ msg_cancel:
         return -EMSGSIZE;
 }
 
-static int __tipc_nl_sk_walk(struct sk_buff *skb, struct netlink_callback *cb,
-                             int (*skb_handler)(struct sk_buff *skb,
-                                                struct netlink_callback *cb,
-                                                struct tipc_sock *tsk))
+int tipc_nl_sk_walk(struct sk_buff *skb, struct netlink_callback *cb,
+                    int (*skb_handler)(struct sk_buff *skb,
+                                       struct netlink_callback *cb,
+                                       struct tipc_sock *tsk))
 {
         struct net *net = sock_net(skb->sk);
         struct tipc_net *tn = tipc_net(net);
@@ -3255,10 +3255,72 @@ out:
 
         return skb->len;
 }
+EXPORT_SYMBOL(tipc_nl_sk_walk);
+
+int tipc_sk_fill_sock_diag(struct sk_buff *skb, struct tipc_sock *tsk,
+                           u32 sk_filter_state,
+                           u64 (*tipc_diag_gen_cookie)(struct sock *sk))
+{
+        struct sock *sk = &tsk->sk;
+        struct nlattr *attrs;
+        struct nlattr *stat;
+
+        /*filter response w.r.t sk_state*/
+        if (!(sk_filter_state & (1 << sk->sk_state)))
+                return 0;
+
+        attrs = nla_nest_start(skb, TIPC_NLA_SOCK);
+        if (!attrs)
+                goto msg_cancel;
+
+        if (__tipc_nl_add_sk_info(skb, tsk))
+                goto attr_msg_cancel;
+
+        if (nla_put_u32(skb, TIPC_NLA_SOCK_TYPE, (u32)sk->sk_type) ||
+            nla_put_u32(skb, TIPC_NLA_SOCK_TIPC_STATE, (u32)sk->sk_state) ||
+            nla_put_u32(skb, TIPC_NLA_SOCK_INO, sock_i_ino(sk)) ||
+            nla_put_u32(skb, TIPC_NLA_SOCK_UID,
+                        from_kuid_munged(sk_user_ns(sk), sock_i_uid(sk))) ||
+            nla_put_u64_64bit(skb, TIPC_NLA_SOCK_COOKIE,
+                              tipc_diag_gen_cookie(sk),
+                              TIPC_NLA_SOCK_PAD))
+                goto attr_msg_cancel;
+
+        stat = nla_nest_start(skb, TIPC_NLA_SOCK_STAT);
+        if (!stat)
+                goto attr_msg_cancel;
+
+        if (nla_put_u32(skb, TIPC_NLA_SOCK_STAT_RCVQ,
+                        skb_queue_len(&sk->sk_receive_queue)) ||
+            nla_put_u32(skb, TIPC_NLA_SOCK_STAT_SENDQ,
+                        skb_queue_len(&sk->sk_write_queue)))
+                goto stat_msg_cancel;
+
+        if (tsk->cong_link_cnt &&
+            nla_put_flag(skb, TIPC_NLA_SOCK_STAT_LINK_CONG))
+                goto stat_msg_cancel;
+
+        if (tsk_conn_cong(tsk) &&
+            nla_put_flag(skb, TIPC_NLA_SOCK_STAT_CONN_CONG))
+                goto stat_msg_cancel;
+
+        nla_nest_end(skb, stat);
+        nla_nest_end(skb, attrs);
+
+        return 0;
+
+stat_msg_cancel:
+        nla_nest_cancel(skb, stat);
+attr_msg_cancel:
+        nla_nest_cancel(skb, attrs);
+msg_cancel:
+        return -EMSGSIZE;
+}
+EXPORT_SYMBOL(tipc_sk_fill_sock_diag);
 
 int tipc_nl_sk_dump(struct sk_buff *skb, struct netlink_callback *cb)
 {
-        return __tipc_nl_sk_walk(skb, cb, __tipc_nl_add_sk);
+        return tipc_nl_sk_walk(skb, cb, __tipc_nl_add_sk);
 }
 
 /* Caller should hold socket lock for the passed tipc socket. */