Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

Pull networking changes from David Miller:

1) Allow to dump, monitor, and change the bridge multicast database
   using netlink.  From Cong Wang.

2) RFC 5961 TCP blind data injection attack mitigation, from Eric
   Dumazet.

3) Networking user namespace support from Eric W. Biederman.

4) tuntap/virtio-net multiqueue support by Jason Wang.

5) Support for checksum offload of encapsulated packets (basically,
   tunneled traffic can still be checksummed by HW).  From Joseph
   Gasparakis.

6) Allow BPF filter access to VLAN tags, from Eric Dumazet and
   Daniel Borkmann.

7) Bridge port parameters over netlink and BPDU blocking support
   from Stephen Hemminger.

8) Improve data access patterns during inet socket demux by rearranging
   socket layout, from Eric Dumazet.

9) TIPC protocol updates and cleanups from Ying Xue, Paul Gortmaker, and
   Jon Maloy.

10) Update TCP socket hash sizing to be more in line with current day
    realities.  The existing heurstics were choosen a decade ago.
    From Eric Dumazet.

11) Fix races, queue bloat, and excessive wakeups in ATM and
    associated drivers, from Krzysztof Mazur and David Woodhouse.

12) Support DOVE (Distributed Overlay Virtual Ethernet) extensions
    in VXLAN driver, from David Stevens.

13) Add "oops_only" mode to netconsole, from Amerigo Wang.

14) Support set and query of VEB/VEPA bridge mode via PF_BRIDGE, also
    allow DCB netlink to work on namespaces other than the initial
    namespace.  From John Fastabend.

15) Support PTP in the Tigon3 driver, from Matt Carlson.

16) tun/vhost zero copy fixes and improvements, plus turn it on
    by default, from Michael S. Tsirkin.

17) Support per-association statistics in SCTP, from Michele
    Baldessari.

And many, many, driver updates, cleanups, and improvements.  Too
numerous to mention individually.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1722 commits)
  net/mlx4_en: Add support for destination MAC in steering rules
  net/mlx4_en: Use generic etherdevice.h functions.
  net: ethtool: Add destination MAC address to flow steering API
  bridge: add support of adding and deleting mdb entries
  bridge: notify mdb changes via netlink
  ndisc: Unexport ndisc_{build,send}_skb().
  uapi: add missing netconf.h to export list
  pkt_sched: avoid requeues if possible
  solos-pci: fix double-free of TX skb in DMA mode
  bnx2: Fix accidental reversions.
  bna: Driver Version Updated to 3.1.2.1
  bna: Firmware update
  bna: Add RX State
  bna: Rx Page Based Allocation
  bna: TX Intr Coalescing Fix
  bna: Tx and Rx Optimizations
  bna: Code Cleanup and Enhancements
  ath9k: check pdata variable before dereferencing it
  ath5k: RX timestamp is reported at end of frame
  ath9k_htc: RX timestamp is reported at end of frame
  ...

1 files changed, 26 insertions, 19 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 181fc8234a52..a13692560e63 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3552,6 +3552,24 @@ static bool tcp_process_frto(struct sock *sk, int flag)
         return false;
 }
 
+/* RFC 5961 7 [ACK Throttling] */
+static void tcp_send_challenge_ack(struct sock *sk)
+{
+        /* unprotected vars, we dont care of overwrites */
+        static u32 challenge_timestamp;
+        static unsigned int challenge_count;
+        u32 now = jiffies / HZ;
+
+        if (now != challenge_timestamp) {
+                challenge_timestamp = now;
+                challenge_count = 0;
+        }
+        if (++challenge_count <= sysctl_tcp_challenge_ack_limit) {
+                NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPCHALLENGEACK);
+                tcp_send_ack(sk);
+        }
+}
+
 /* This routine deals with incoming acks, but not outgoing ones. */
 static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
 {
@@ -3571,8 +3589,14 @@ static int tcp_ack(struct sock *sk, const struct sk_buff *skb, int flag)
         /* If the ack is older than previous acks
          * then we can probably ignore it.
          */
-        if (before(ack, prior_snd_una))
+        if (before(ack, prior_snd_una)) {
+                /* RFC 5961 5.2 [Blind Data Injection Attack].[Mitigation] */
+                if (before(ack, prior_snd_una - tp->max_window)) {
+                        tcp_send_challenge_ack(sk);
+                        return -1;
+                }
                 goto old_ack;
+        }
 
         /* If the ack includes data we haven't sent yet, discard
          * this segment (RFC793 Section 3.9).
@@ -5244,23 +5268,6 @@ out:
 }
 #endif /* CONFIG_NET_DMA */
 
-static void tcp_send_challenge_ack(struct sock *sk)
-{
-        /* unprotected vars, we dont care of overwrites */
-        static u32 challenge_timestamp;
-        static unsigned int challenge_count;
-        u32 now = jiffies / HZ;
-
-        if (now != challenge_timestamp) {
-                challenge_timestamp = now;
-                challenge_count = 0;
-        }
-        if (++challenge_count <= sysctl_tcp_challenge_ack_limit) {
-                NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPCHALLENGEACK);
-                tcp_send_ack(sk);
-        }
-}
-
 /* Does PAWS and seqno based validation of an incoming segment, flags will
  * play significant role here.
  */
@@ -5992,7 +5999,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                                  */
                                 if (req) {
                                         tcp_synack_rtt_meas(sk, req);
-                                        tp->total_retrans = req->retrans;
+                                        tp->total_retrans = req->num_retrans;
 
                                         reqsk_fastopen_remove(sk, req, false);
                                 } else {