1. 31 Oct, 2020 39 commits
  2. 30 Oct, 2020 1 commit
    • Jakub Kicinski's avatar
      Merge branch 'sctp-implement-rfc6951-udp-encapsulation-of-sctp' · be25f43a
      Jakub Kicinski authored
      Xin Long says:
      
      ====================
      sctp: Implement RFC6951: UDP Encapsulation of SCTP
      
      Description From the RFC:
      
         The Main Reasons:
      
         o  To allow SCTP traffic to pass through legacy NATs, which do not
            provide native SCTP support as specified in [BEHAVE] and
            [NATSUPP].
      
         o  To allow SCTP to be implemented on hosts that do not provide
            direct access to the IP layer.  In particular, applications can
            use their own SCTP implementation if the operating system does not
            provide one.
      
         Implementation Notes:
      
         UDP-encapsulated SCTP is normally communicated between SCTP stacks
         using the IANA-assigned UDP port number 9899 (sctp-tunneling) on both
         ends.  There are circumstances where other ports may be used on
         either end, and it might be required to use ports other than the
         registered port.
      
         Each SCTP stack uses a single local UDP encapsulation port number as
         the destination port for all its incoming SCTP packets, this greatly
         simplifies implementation design.
      
         An SCTP implementation supporting UDP encapsulation MUST maintain a
         remote UDP encapsulation port number per destination address for each
         SCTP association.  Again, because the remote stack may be using ports
         other than the well-known port, each port may be different from each
         stack.  However, because of remapping of ports by NATs, the remote
         ports associated with different remote IP addresses may not be
         identical, even if they are associated with the same stack.
      
         Because the well-known port might not be used, implementations need
         to allow other port numbers to be specified as a local or remote UDP
         encapsulation port number through APIs.
      
      Patches:
      
         This patchset is using the udp4/6 tunnel APIs to implement the UDP
         Encapsulation of SCTP with not much change in SCTP protocol stack
         and with all current SCTP features keeped in Linux Kernel.
      
         1 - 4: Fix some UDP issues that may be triggered by SCTP over UDP.
         5 - 7: Process incoming UDP encapsulated packets and ICMP packets.
         8 -10: Remote encap port's update by sysctl, sockopt and packets.
         11-14: Process outgoing pakects with UDP encapsulated and its GSO.
         15-16: Add the part from draft-tuexen-tsvwg-sctp-udp-encaps-cons-03.
            17: Enable this feature.
      
      Tests:
      
        - lksctp-tools/src/func_tests with UDP Encapsulation enabled/disabled:
      
            Both make v4test and v6test passed.
      
        - sctp-tests with UDP Encapsulation enabled/disabled:
      
            repeatability/procdumps/sctpdiag/gsomtuchange/extoverflow/
            sctphashtable passed. Others failed as expected due to those
            "iptables -p sctp" rules.
      
        - netperf on lo/netns/virtio_net, with gso enabled/disabled and
          with ip_checksum enabled/disabled, with UDP Encapsulation
          enabled/disabled:
      
            No clear performance dropped.
      
      v1->v2:
        - Fix some incorrect code in the patches 5,6,8,10,11,13,14,17, suggested
          by Marcelo.
        - Append two patches 15-16 to add the Additional Considerations for UDP
          Encapsulation of SCTP from draft-tuexen-tsvwg-sctp-udp-encaps-cons-03.
      v2->v3:
        - remove the cleanup code in patch 2, suggested by Willem.
        - remove the patch 3 and fix the checksum in the new patch 3 after
          talking with Paolo, Marcelo and Guillaume.
        - add 'select NET_UDP_TUNNEL' in patch 4 to solve a compiling error.
        - fix __be16 type cast warning in patch 8.
        - fix the wrong endian orders when setting values in 14,16.
      v3->v4:
        - add entries in ip-sysctl.rst in patch 7,16, as Marcelo Suggested.
        - not create udp socks when udp_port is set to 0 in patch 16, as
          Marcelo noticed.
      v4->v5:
        - improve the description for udp_port and encap_port entries in patch
          7, 16.
        - use 0 as the default udp_port.
      ====================
      
      Link: https://lore.kernel.org/r/cover.1603955040.git.lucien.xin@gmail.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      be25f43a