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

Pull networking fixes from David Miller:
 "Several fixes here. Basically split down the line between newly
  introduced regressions and long existing problems:

   1) Double free in tipc_enable_bearer(), from Cong Wang.

   2) Many fixes to nf_conncount, from Florian Westphal.

   3) op->get_regs_len() can throw an error, check it, from Yunsheng
      Lin.

   4) Need to use GFP_ATOMIC in *_add_hash_mac_address() of fsl/fman
      driver, from Scott Wood.

   5) Inifnite loop in fib_empty_table(), from Yue Haibing.

   6) Use after free in ax25_fillin_cb(), from Cong Wang.

   7) Fix socket locking in nr_find_socket(), also from Cong Wang.

   8) Fix WoL wakeup enable in r8169, from Heiner Kallweit.

   9) On 32-bit sock->sk_stamp is not thread-safe, from Deepa Dinamani.

  10) Fix ptr_ring wrap during queue swap, from Cong Wang.

  11) Missing shutdown callback in hinic driver, from Xue Chaojing.

  12) Need to return NULL on error from ip6_neigh_lookup(), from Stefano
      Brivio.

  13) BPF out of bounds speculation fixes from Daniel Borkmann"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (57 commits)
  ipv6: Consider sk_bound_dev_if when binding a socket to an address
  ipv6: Fix dump of specific table with strict checking
  bpf: add various test cases to selftests
  bpf: prevent out of bounds speculation on pointer arithmetic
  bpf: fix check_map_access smin_value test when pointer contains offset
  bpf: restrict unknown scalars of mixed signed bounds for unprivileged
  bpf: restrict stack pointer arithmetic for unprivileged
  bpf: restrict map value pointer arithmetic for unprivileged
  bpf: enable access to ax register also from verifier rewrite
  bpf: move tmp variable into ax register in interpreter
  bpf: move {prev_,}insn_idx into verifier env
  isdn: fix kernel-infoleak in capi_unlocked_ioctl
  ipv6: route: Fix return value of ip6_neigh_lookup() on neigh_create() error
  net/hamradio/6pack: use mod_timer() to rearm timers
  net-next/hinic:add shutdown callback
  net: hns3: call hns3_nic_net_open() while doing HNAE3_UP_CLIENT
  ip: validate header length on virtual device xmit
  tap: call skb_probe_transport_header after setting skb->dev
  ptr_ring: wrap back ->producer in __ptr_ring_swap_queue()
  net: rds: remove unnecessary NULL check
  ...

1 files changed, 239 insertions, 1 deletions

diff --git a/Documentation/networking/snmp_counter.rst b/Documentation/networking/snmp_counter.rst
index f8eb77ddbd44..b0dfdaaca512 100644
--- a/Documentation/networking/snmp_counter.rst
+++ b/Documentation/networking/snmp_counter.rst
@@ -571,7 +571,97 @@ duplicate packet is received.
 
 * TcpExtTCPDSACKOfoRecv
 The TCP stack receives a DSACK, which indicate an out of order
-duplciate packet is received.
+duplicate packet is received.
+
+TCP out of order
+===============
+* TcpExtTCPOFOQueue
+The TCP layer receives an out of order packet and has enough memory
+to queue it.
+
+* TcpExtTCPOFODrop
+The TCP layer receives an out of order packet but doesn't have enough
+memory, so drops it. Such packets won't be counted into
+TcpExtTCPOFOQueue.
+
+* TcpExtTCPOFOMerge
+The received out of order packet has an overlay with the previous
+packet. the overlay part will be dropped. All of TcpExtTCPOFOMerge
+packets will also be counted into TcpExtTCPOFOQueue.
+
+TCP PAWS
+=======
+PAWS (Protection Against Wrapped Sequence numbers) is an algorithm
+which is used to drop old packets. It depends on the TCP
+timestamps. For detail information, please refer the `timestamp wiki`_
+and the `RFC of PAWS`_.
+
+.. _RFC of PAWS: https://tools.ietf.org/html/rfc1323#page-17
+.. _timestamp wiki: https://en.wikipedia.org/wiki/Transmission_Control_Protocol#TCP_timestamps
+
+* TcpExtPAWSActive
+Packets are dropped by PAWS in Syn-Sent status.
+
+* TcpExtPAWSEstab
+Packets are dropped by PAWS in any status other than Syn-Sent.
+
+TCP ACK skip
+===========
+In some scenarios, kernel would avoid sending duplicate ACKs too
+frequently. Please find more details in the tcp_invalid_ratelimit
+section of the `sysctl document`_. When kernel decides to skip an ACK
+due to tcp_invalid_ratelimit, kernel would update one of below
+counters to indicate the ACK is skipped in which scenario. The ACK
+would only be skipped if the received packet is either a SYN packet or
+it has no data.
+
+.. _sysctl document: https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt
+
+* TcpExtTCPACKSkippedSynRecv
+The ACK is skipped in Syn-Recv status. The Syn-Recv status means the
+TCP stack receives a SYN and replies SYN+ACK. Now the TCP stack is
+waiting for an ACK. Generally, the TCP stack doesn't need to send ACK
+in the Syn-Recv status. But in several scenarios, the TCP stack need
+to send an ACK. E.g., the TCP stack receives the same SYN packet
+repeately, the received packet does not pass the PAWS check, or the
+received packet sequence number is out of window. In these scenarios,
+the TCP stack needs to send ACK. If the ACk sending frequency is higher than
+tcp_invalid_ratelimit allows, the TCP stack will skip sending ACK and
+increase TcpExtTCPACKSkippedSynRecv.
+
+
+* TcpExtTCPACKSkippedPAWS
+The ACK is skipped due to PAWS (Protect Against Wrapped Sequence
+numbers) check fails. If the PAWS check fails in Syn-Recv, Fin-Wait-2
+or Time-Wait statuses, the skipped ACK would be counted to
+TcpExtTCPACKSkippedSynRecv, TcpExtTCPACKSkippedFinWait2 or
+TcpExtTCPACKSkippedTimeWait. In all other statuses, the skipped ACK
+would be counted to TcpExtTCPACKSkippedPAWS.
+
+* TcpExtTCPACKSkippedSeq
+The sequence number is out of window and the timestamp passes the PAWS
+check and the TCP status is not Syn-Recv, Fin-Wait-2, and Time-Wait.
+
+* TcpExtTCPACKSkippedFinWait2
+The ACK is skipped in Fin-Wait-2 status, the reason would be either
+PAWS check fails or the received sequence number is out of window.
+
+* TcpExtTCPACKSkippedTimeWait
+Tha ACK is skipped in Time-Wait status, the reason would be either
+PAWS check failed or the received sequence number is out of window.
+
+* TcpExtTCPACKSkippedChallenge
+The ACK is skipped if the ACK is a challenge ACK. The RFC 5961 defines
+3 kind of challenge ACK, please refer `RFC 5961 section 3.2`_,
+`RFC 5961 section 4.2`_ and `RFC 5961 section 5.2`_. Besides these
+three scenarios, In some TCP status, the linux TCP stack would also
+send challenge ACKs if the ACK number is before the first
+unacknowledged number (more strict than `RFC 5961 section 5.2`_).
+
+.. _RFC 5961 section 3.2: https://tools.ietf.org/html/rfc5961#page-7
+.. _RFC 5961 section 4.2: https://tools.ietf.org/html/rfc5961#page-9
+.. _RFC 5961 section 5.2: https://tools.ietf.org/html/rfc5961#page-11
+
 
 examples
 =======
@@ -1188,3 +1278,151 @@ Run nstat on server B::
 We have deleted the default route on server B. Server B couldn't find
 a route for the 8.8.8.8 IP address, so server B increased
 IpOutNoRoutes.
+
+TcpExtTCPACKSkippedSynRecv
+------------------------
+In this test, we send 3 same SYN packets from client to server. The
+first SYN will let server create a socket, set it to Syn-Recv status,
+and reply a SYN/ACK. The second SYN will let server reply the SYN/ACK
+again, and record the reply time (the duplicate ACK reply time). The
+third SYN will let server check the previous duplicate ACK reply time,
+and decide to skip the duplicate ACK, then increase the
+TcpExtTCPACKSkippedSynRecv counter.
+
+Run tcpdump to capture a SYN packet::
+
+  nstatuser@nstat-a:~$ sudo tcpdump -c 1 -w /tmp/syn.pcap port 9000
+  tcpdump: listening on ens3, link-type EN10MB (Ethernet), capture size 262144 bytes
+
+Open another terminal, run nc command::
+
+  nstatuser@nstat-a:~$ nc nstat-b 9000
+
+As the nstat-b didn't listen on port 9000, it should reply a RST, and
+the nc command exited immediately. It was enough for the tcpdump
+command to capture a SYN packet. A linux server might use hardware
+offload for the TCP checksum, so the checksum in the /tmp/syn.pcap
+might be not correct. We call tcprewrite to fix it::
+
+  nstatuser@nstat-a:~$ tcprewrite --infile=/tmp/syn.pcap --outfile=/tmp/syn_fixcsum.pcap --fixcsum
+
+On nstat-b, we run nc to listen on port 9000::
+
+  nstatuser@nstat-b:~$ nc -lkv 9000
+  Listening on [0.0.0.0] (family 0, port 9000)
+
+On nstat-a, we blocked the packet from port 9000, or nstat-a would send
+RST to nstat-b::
+
+  nstatuser@nstat-a:~$ sudo iptables -A INPUT -p tcp --sport 9000 -j DROP
+
+Send 3 SYN repeatly to nstat-b::
+
+  nstatuser@nstat-a:~$ for i in {1..3}; do sudo tcpreplay -i ens3 /tmp/syn_fixcsum.pcap; done
+
+Check snmp cunter on nstat-b::
+
+  nstatuser@nstat-b:~$ nstat | grep -i skip
+  TcpExtTCPACKSkippedSynRecv      1                  0.0
+
+As we expected, TcpExtTCPACKSkippedSynRecv is 1.
+
+TcpExtTCPACKSkippedPAWS
+----------------------
+To trigger PAWS, we could send an old SYN.
+
+On nstat-b, let nc listen on port 9000::
+
+  nstatuser@nstat-b:~$ nc -lkv 9000
+  Listening on [0.0.0.0] (family 0, port 9000)
+
+On nstat-a, run tcpdump to capture a SYN::
+
+  nstatuser@nstat-a:~$ sudo tcpdump -w /tmp/paws_pre.pcap -c 1 port 9000
+  tcpdump: listening on ens3, link-type EN10MB (Ethernet), capture size 262144 bytes
+
+On nstat-a, run nc as a client to connect nstat-b::
+
+  nstatuser@nstat-a:~$ nc -v nstat-b 9000
+  Connection to nstat-b 9000 port [tcp/*] succeeded!
+
+Now the tcpdump has captured the SYN and exit. We should fix the
+checksum::
+
+  nstatuser@nstat-a:~$ tcprewrite --infile /tmp/paws_pre.pcap --outfile /tmp/paws.pcap --fixcsum
+
+Send the SYN packet twice::
+
+  nstatuser@nstat-a:~$ for i in {1..2}; do sudo tcpreplay -i ens3 /tmp/paws.pcap; done
+
+On nstat-b, check the snmp counter::
+
+  nstatuser@nstat-b:~$ nstat | grep -i skip
+  TcpExtTCPACKSkippedPAWS         1                  0.0
+
+We sent two SYN via tcpreplay, both of them would let PAWS check
+failed, the nstat-b replied an ACK for the first SYN, skipped the ACK
+for the second SYN, and updated TcpExtTCPACKSkippedPAWS.
+
+TcpExtTCPACKSkippedSeq
+--------------------
+To trigger TcpExtTCPACKSkippedSeq, we send packets which have valid
+timestamp (to pass PAWS check) but the sequence number is out of
+window. The linux TCP stack would avoid to skip if the packet has
+data, so we need a pure ACK packet. To generate such a packet, we
+could create two sockets: one on port 9000, another on port 9001. Then
+we capture an ACK on port 9001, change the source/destination port
+numbers to match the port 9000 socket. Then we could trigger
+TcpExtTCPACKSkippedSeq via this packet.
+
+On nstat-b, open two terminals, run two nc commands to listen on both
+port 9000 and port 9001::
+
+  nstatuser@nstat-b:~$ nc -lkv 9000
+  Listening on [0.0.0.0] (family 0, port 9000)
+
+  nstatuser@nstat-b:~$ nc -lkv 9001
+  Listening on [0.0.0.0] (family 0, port 9001)
+
+On nstat-a, run two nc clients::
+
+  nstatuser@nstat-a:~$ nc -v nstat-b 9000
+  Connection to nstat-b 9000 port [tcp/*] succeeded!
+
+  nstatuser@nstat-a:~$ nc -v nstat-b 9001
+  Connection to nstat-b 9001 port [tcp/*] succeeded!
+
+On nstat-a, run tcpdump to capture an ACK::
+
+  nstatuser@nstat-a:~$ sudo tcpdump -w /tmp/seq_pre.pcap -c 1 dst port 9001
+  tcpdump: listening on ens3, link-type EN10MB (Ethernet), capture size 262144 bytes
+
+On nstat-b, send a packet via the port 9001 socket. E.g. we sent a
+string 'foo' in our example::
+
+  nstatuser@nstat-b:~$ nc -lkv 9001
+  Listening on [0.0.0.0] (family 0, port 9001)
+  Connection from nstat-a 42132 received!
+  foo
+
+On nstat-a, the tcpdump should have caputred the ACK. We should check
+the source port numbers of the two nc clients::
+
+  nstatuser@nstat-a:~$ ss -ta '( dport = :9000 || dport = :9001 )' | tee
+  State  Recv-Q   Send-Q         Local Address:Port           Peer Address:Port
+  ESTAB  0        0            192.168.122.250:50208       192.168.122.251:9000
+  ESTAB  0        0            192.168.122.250:42132       192.168.122.251:9001
+
+Run tcprewrite, change port 9001 to port 9000, chagne port 42132 to
+port 50208::
+
+  nstatuser@nstat-a:~$ tcprewrite --infile /tmp/seq_pre.pcap --outfile /tmp/seq.pcap -r 9001:9000 -r 42132:50208 --fixcsum
+
+Now the /tmp/seq.pcap is the packet we need. Send it to nstat-b::
+
+  nstatuser@nstat-a:~$ for i in {1..2}; do sudo tcpreplay -i ens3 /tmp/seq.pcap; done
+
+Check TcpExtTCPACKSkippedSeq on nstat-b::
+
+  nstatuser@nstat-b:~$ nstat | grep -i skip
+  TcpExtTCPACKSkippedSeq          1                  0.0