inet_diag: remove duplicate code from inet_twsk_diag_dump()

timewait sockets now share a common base with established sockets.

inet_twsk_diag_dump() can use inet_diag_bc_sk() instead of duplicating
code, granted that inet_diag_bc_sk() does proper userlocks
initialization.

twsk_build_assert() will catch any future changes that could break
the assumptions.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 81751f12645f6224a7f076dea1da2fc0d638819a..0c974d3499ed77190e54015d653463726e98f9ca 100644 (file)
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -508,7 +508,7 @@ int inet_diag_bc_sk(const struct nlattr *bc, struct sock *sk)
        }
        entry.sport = inet->inet_num;
        entry.dport = ntohs(inet->inet_dport);
-       entry.userlocks = sk->sk_userlocks;
+       entry.userlocks = (sk->sk_state != TCP_TIME_WAIT) ? sk->sk_userlocks : 0;
 
        return inet_diag_bc_run(bc, &entry);
 }
@@ -642,37 +642,44 @@ static int inet_csk_diag_dump(struct sock *sk,
                                  cb->nlh->nlmsg_seq, NLM_F_MULTI, cb->nlh);
 }
 
+static void twsk_build_assert(void)
+{
+       BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_family) !=
+                    offsetof(struct sock, sk_family));
+
+       BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_num) !=
+                    offsetof(struct inet_sock, inet_num));
+
+       BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_dport) !=
+                    offsetof(struct inet_sock, inet_dport));
+
+       BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_rcv_saddr) !=
+                    offsetof(struct inet_sock, inet_rcv_saddr));
+
+       BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_daddr) !=
+                    offsetof(struct inet_sock, inet_daddr));
+
+#if IS_ENABLED(CONFIG_IPV6)
+       BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_v6_rcv_saddr) !=
+                    offsetof(struct sock, sk_v6_rcv_saddr));
+
+       BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_v6_daddr) !=
+                    offsetof(struct sock, sk_v6_daddr));
+#endif
+}
+
 static int inet_twsk_diag_dump(struct sock *sk,
                               struct sk_buff *skb,
                               struct netlink_callback *cb,
                               struct inet_diag_req_v2 *r,
                               const struct nlattr *bc)
 {
-       struct inet_timewait_sock *tw = inet_twsk(sk);
+       twsk_build_assert();
 
-       if (bc != NULL) {
-               struct inet_diag_entry entry;
-
-               entry.family = tw->tw_family;
-#if IS_ENABLED(CONFIG_IPV6)
-               if (tw->tw_family == AF_INET6) {
-                       entry.saddr = tw->tw_v6_rcv_saddr.s6_addr32;
-                       entry.daddr = tw->tw_v6_daddr.s6_addr32;
-               } else
-#endif
-               {
-                       entry.saddr = &tw->tw_rcv_saddr;
-                       entry.daddr = &tw->tw_daddr;
-               }
-               entry.sport = tw->tw_num;
-               entry.dport = ntohs(tw->tw_dport);
-               entry.userlocks = 0;
-
-               if (!inet_diag_bc_run(bc, &entry))
-                       return 0;
-       }
+       if (!inet_diag_bc_sk(bc, sk))
+               return 0;
 
-       return inet_twsk_diag_fill(tw, skb, r,
+       return inet_twsk_diag_fill(inet_twsk(sk), skb, r,
                                   NETLINK_CB(cb->skb).portid,
                                   cb->nlh->nlmsg_seq, NLM_F_MULTI, cb->nlh);
 }