1. 03 Jul, 2017 31 commits
  2. 02 Jul, 2017 1 commit
  3. 01 Jul, 2017 8 commits
    • David S. Miller's avatar
      Merge branch 'bpf-Add-support-for-sock_ops' · bcdb239b
      David S. Miller authored
      Lawrence Brakmo says:
      
      ====================
      bpf: Add support for sock_ops
      
      Created a new BPF program type, BPF_PROG_TYPE_SOCK_OPS, and a corresponding
      struct that allows BPF programs of this type to access some of the
      socket's fields (such as IP addresses, ports, etc.) and setting
      connection parameters such as buffer sizes, initial window, SYN/SYN-ACK
      RTOs, etc.
      
      Unlike current BPF program types that expect to be called at a particular
      place in the network stack code, SOCK_OPS program can be called at
      different places and use an "op" field to indicate the context. There
      are currently two types of operations, those whose effect is through
      their return value and those whose effect is through the new
      bpf_setsocketop BPF helper function.
      
      Example operands of the first type are:
        BPF_SOCK_OPS_TIMEOUT_INIT
        BPF_SOCK_OPS_RWND_INIT
        BPF_SOCK_OPS_NEEDS_ECN
      
      Example operands of the secont type are:
        BPF_SOCK_OPS_TCP_CONNECT_CB
        BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB
        BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB
      
      Current operands are only called during connection establishment so
      there should not be any BPF overheads after connection establishment. The
      main idea is to use connection information form both hosts, such as IP
      addresses and ports to allow setting of per connection parameters to
      optimize the connection's peformance.
      
      Alghough there are already 3 mechanisms to set parameters (sysctls,
      route metrics and setsockopts), this new mechanism provides some
      disticnt advantages. Unlike sysctls, it can set parameters per
      connection. In contrast to route metrics, it can also use port numbers
      and information provided by a user level program. In addition, it could
      set parameters probabilistically for evaluation purposes (i.e. do
      something different on 10% of the flows and compare results with the
      other 90% of the flows). Also, in cases where IPv6 addresses contain
      geographic information, the rules to make changes based on the distance
      (or RTT) between the hosts are much easier than route metric rules and
      can be global. Finally, unlike setsockopt, it does not require
      application changes and it can be updated easily at any time.
      
      It uses the existing bpf cgroups infrastructure so the programs can be
      attached per cgroup with full inheritance support. Although the bpf cgroup
      framework already contains a sock related program type (BPF_PROG_TYPE_CGROUP_SOCK),
      I created the new type (BPF_PROG_TYPE_SOCK_OPS) beccause the existing type
      expects to be called only once during the connections's lifetime. In contrast,
      the new program type will be called multiple times from different places in the
      network stack code.  For example, before sending SYN and SYN-ACKs to set
      an appropriate timeout, when the connection is established to set congestion
      control, etc. As a result it has "op" field to specify the type of operation
      requested.
      
      This patch set also includes sample BPF programs to demostrate the differnet
      features.
      
      v2: Formatting changes, rebased to latest net-next
      
      v3: Fixed build issues, changed socket_ops to sock_ops throught,
          fixed formatting issues, removed the syscall to load sock_ops
          program and added functionality to use existing bpf attach and
          bpf detach system calls, removed reader/writer locks in
          sock_bpfops.c (used when saving sock_ops global program)
          and fixed missing module refcount increment.
      
      v4: Removed global sock_ops program and instead used existing cgroup bpf
          infrastructure to support a new BPF_CGROUP_ATTCH type.
      
      v5: fixed kbuild warning happening in bpf-cgroup.h
          removed automatic converstion to host byte order from some sock_ops
            fields (ipv4 and ipv6 addresses, remote port)
          Added conversion to host byte order in some of the sample programs
          Added to sample BPF program comments about using load_sock_ops to load
          Removed is_req_sock field from bpf_sock_ops_kern and related places,
            using sk_fullsock() instead.
      
      v6: fixes to BPF helper function setsockopt (possible NULL deferencing, etc.)
      ====================
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      bcdb239b
    • Lawrence Brakmo's avatar
      bpf: update tools/include/uapi/linux/bpf.h · 04df41e3
      Lawrence Brakmo authored
      Update tools/include/uapi/linux/bpf.h to include changes related to new
      bpf sock_ops program type.
      Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      04df41e3
    • Lawrence Brakmo's avatar
      bpf: Sample bpf program to set sndcwnd clamp · 6c4a01b2
      Lawrence Brakmo authored
      Sample BPF program, tcp_clamp_kern.c, to demostrate the use
      of setting the sndcwnd clamp. This program assumes that if the
      first 5.5 bytes of the host's IPv6 addresses are the same, then
      the hosts are in the same datacenter and sets sndcwnd clamp to
      100 packets, SYN and SYN-ACK RTOs to 10ms and send/receive buffer
      sizes to 150KB.
      Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      6c4a01b2
    • Lawrence Brakmo's avatar
      bpf: Adds support for setting sndcwnd clamp · 13bf9641
      Lawrence Brakmo authored
      Adds a new bpf_setsockopt for TCP sockets, TCP_BPF_SNDCWND_CLAMP, which
      sets the initial congestion window. It is useful to limit the sndcwnd
      when the host are close to each other (small RTT).
      Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      13bf9641
    • Lawrence Brakmo's avatar
      bpf: Sample BPF program to set initial cwnd · 7bc62e28
      Lawrence Brakmo authored
      Sample BPF program that assumes hosts are far away (i.e. large RTTs)
      and sets initial cwnd and initial receive window to 40 packets,
      send and receive buffers to 1.5MB.
      
      In practice there would be a test to insure the hosts are actually
      far enough away.
      Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      7bc62e28
    • Lawrence Brakmo's avatar
      bpf: Adds support for setting initial cwnd · fc747810
      Lawrence Brakmo authored
      Adds a new bpf_setsockopt for TCP sockets, TCP_BPF_IW, which sets the
      initial congestion window. This can be used when the hosts are far
      apart (large RTTs) and it is safe to start with a large inital cwnd.
      Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      fc747810
    • Lawrence Brakmo's avatar
      bpf: Sample BPF program to set congestion control · bb56d444
      Lawrence Brakmo authored
      Sample BPF program that sets congestion control to dctcp when both hosts
      are within the same datacenter. In this example that is assumed to be
      when they have the first 5.5 bytes of their IPv6 address are the same.
      Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      bb56d444
    • Lawrence Brakmo's avatar
      bpf: Add support for changing congestion control · 91b5b21c
      Lawrence Brakmo authored
      Added support for changing congestion control for SOCK_OPS bpf
      programs through the setsockopt bpf helper function. It also adds
      a new SOCK_OPS op, BPF_SOCK_OPS_NEEDS_ECN, that is needed for
      congestion controls, like dctcp, that need to enable ECN in the
      SYN packets.
      Signed-off-by: default avatarLawrence Brakmo <brakmo@fb.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      91b5b21c