[ovs-dev] [PATCH ovn v2 2/3] actions: Add new OVN logical fields 'ip.src' and ip.dst'.

Numan Siddique numans at ovn.org
Wed Oct 14 10:50:19 UTC 2020


On Wed, Oct 14, 2020 at 3:50 PM Dumitru Ceara <dceara at redhat.com> wrote:
>
> On 10/14/20 11:15 AM, numans at ovn.org wrote:
> > From: Numan Siddique <numans at ovn.org>
> >
> > Thee new fields are version independent and these can be used in any
>
> Hi Numan,
>
> Nit: s/Thee/These
>
> > OVN action. Right now the usage of these fields are restricted to
> > exchanging the IP source and destination fields.
> >
> > Eg. reject {... ip.src <-> ip.dst ... };
> >
> > "ip.src <-> ip.dst" translates to controller action with "pause" flag set.
> > When pinctrl thread receives the packet in, it checks the IP version of the
> > packet and either does - "ip4.src <-> ip4.dst" or "ip6.src <-> ip6.dst" and
> > resumes the packet to continue with the pipeline.
> >
> > Upcoming patch will make use of these fields.
> >
> > Signed-off-by: Numan Siddique <numans at ovn.org>
> > ---
> >  controller/pinctrl.c         |  49 +++++++++++++++
> >  include/ovn/actions.h        |   4 ++
> >  include/ovn/logical-fields.h |  18 ++++++
> >  lib/actions.c                | 118 +++++++++++++++++++++++++++++++++++
> >  lib/logical-fields.c         |  10 +++
> >  ovn-sb.xml                   |  37 +++++++++++
> >  tests/ovn.at                 |  27 ++++++++
> >  utilities/ovn-trace.c        |  28 +++++++++
> >  8 files changed, 291 insertions(+)
> >
> > diff --git a/controller/pinctrl.c b/controller/pinctrl.c
> > index 631d058458..bc16a82404 100644
> > --- a/controller/pinctrl.c
> > +++ b/controller/pinctrl.c
> > @@ -233,6 +233,11 @@ static void pinctrl_handle_put_icmp_frag_mtu(struct rconn *swconn,
> >                                               struct ofputil_packet_in *pin,
> >                                               struct ofpbuf *userdata,
> >                                               struct ofpbuf *continuation);
> > +static void pinctrl_handle_swap_src_dst_ip(struct rconn *swconn,
> > +                                           const struct flow *in_flow,
> > +                                           struct dp_packet *pkt_in,
> > +                                           struct ofputil_packet_in *pin,
> > +                                           struct ofpbuf *continuation);
> >  static void
> >  pinctrl_handle_event(struct ofpbuf *userdata)
> >      OVS_REQUIRES(pinctrl_mutex);
> > @@ -2835,6 +2840,11 @@ process_packet_in(struct rconn *swconn, const struct ofp_header *msg)
> >          ovs_mutex_unlock(&pinctrl_mutex);
> >          break;
> >
> > +    case ACTION_OPCODE_SWAP_SRC_DST_IP:
> > +        pinctrl_handle_swap_src_dst_ip(swconn, &headers, &packet, &pin,
> > +                                       &continuation);
> > +        break;
> > +
> >      default:
> >          VLOG_WARN_RL(&rl, "unrecognized packet-in opcode %"PRIu32,
> >                       ntohl(ah->opcode));
> > @@ -6508,3 +6518,42 @@ pinctrl_handle_svc_check(struct rconn *swconn, const struct flow *ip_flow,
> >          svc_mon->next_send_time = time_msec() + svc_mon->interval;
> >      }
> >  }
> > +
> > +static void
> > +pinctrl_handle_swap_src_dst_ip(struct rconn *swconn,
> > +                               const struct flow *in_flow,
> > +                               struct dp_packet *pkt_in,
> > +                               struct ofputil_packet_in *pin,
> > +                               struct ofpbuf *continuation)
> > +{
> > +    enum ofp_version version = rconn_get_version(swconn);
> > +    enum ofputil_protocol proto = ofputil_protocol_from_ofp_version(version);
> > +    struct dp_packet *pkt_out;
> > +
> > +    pkt_out = dp_packet_clone(pkt_in);
> > +    pkt_out->l2_5_ofs = pkt_in->l2_5_ofs;
> > +    pkt_out->l2_pad_size = pkt_in->l2_pad_size;
> > +    pkt_out->l3_ofs = pkt_in->l3_ofs;
> > +    pkt_out->l4_ofs = pkt_in->l4_ofs;
> > +
> > +    if (get_dl_type(in_flow) == htons(ETH_TYPE_IP)) {
> > +        /* IPv4 packet. Swap nw_src with nw_dst. */
> > +        packet_set_ipv4(pkt_out, in_flow->nw_dst, in_flow->nw_src,
> > +                        in_flow->nw_tos, in_flow->nw_ttl);
> > +    } else {
> > +        /* IPv6 packet. Swap ip6_src with ip6_dst.
> > +         * We could also use packet_set_ipv6() here, but that would require
> > +         * to extract the 'tc' and 'label' from in_nh->ip6_flow which seems
> > +         * unnecessary. */
> > +        struct ovs_16aligned_ip6_hdr *out_nh = dp_packet_l3(pkt_out);
> > +        union ovs_16aligned_in6_addr tmp = out_nh->ip6_src;
> > +        out_nh->ip6_src = out_nh->ip6_dst;
> > +        out_nh->ip6_dst = tmp;
> > +    }
> > +
> > +    pin->packet = dp_packet_data(pkt_out);
> > +    pin->packet_len = dp_packet_size(pkt_out);
> > +
> > +    queue_msg(swconn, ofputil_encode_resume(pin, continuation, proto));
> > +    dp_packet_delete(pkt_out);
> > +}
> > diff --git a/include/ovn/actions.h b/include/ovn/actions.h
> > index b4e5acabb9..bf1fe848b7 100644
> > --- a/include/ovn/actions.h
> > +++ b/include/ovn/actions.h
> > @@ -97,6 +97,7 @@ struct ovn_extend_table;
> >      OVNACT(DHCP6_REPLY,       ovnact_null)            \
> >      OVNACT(ICMP6_ERROR,       ovnact_nest)            \
> >      OVNACT(REJECT,            ovnact_nest)            \
> > +    OVNACT(OVNFIELD_EXCHANGE, ovnact_move)            \
> >
> >  /* enum ovnact_type, with a member OVNACT_<ENUM> for each action. */
> >  enum OVS_PACKED_ENUM ovnact_type {
> > @@ -612,6 +613,9 @@ enum action_opcode {
> >       * The actions, in OpenFlow 1.3 format, follow the action_header.
> >       */
> >      ACTION_OPCODE_REJECT,
> > +
> > +    /* ip.src <-> ip.dst */
> > +    ACTION_OPCODE_SWAP_SRC_DST_IP,
> >  };
> >
> >  /* Header. */
> > diff --git a/include/ovn/logical-fields.h b/include/ovn/logical-fields.h
> > index ac6f2f909b..bb6daa50ca 100644
> > --- a/include/ovn/logical-fields.h
> > +++ b/include/ovn/logical-fields.h
> > @@ -116,6 +116,24 @@ enum ovn_field_id {
> >       */
> >      OVN_ICMP6_FRAG_MTU,
> >
> > +    /*
> > +     * Name: "ip.src"
> > +     * Type: be128
> > +     * Description: Sets the field MFF_IPV4_SRC if eth.type == 0x800 (IPv4)
> > +     *              or sets the field MFF_IPV6_SRC if
> > +     *              eth.type == 0x86dd (IPV6).
> > +     */
> > +    OVN_IP_SRC,
> > +
> > +    /*
> > +     * Name: "ip.dst"
> > +     * Type: be128
> > +     * Description: Sets the field MFF_IPV4_DST if eth.type == 0x800 (IPv4)
> > +     *              or sets the field MFF_IPV6_DST if
> > +     *              eth.type == 0x86dd (IPV6).
> > +     */
> > +    OVN_IP_DST,
> > +
> >      OVN_FIELD_N_IDS
> >  };
> >
> > diff --git a/lib/actions.c b/lib/actions.c
> > index 1e1bdeff24..e9c77d2a0a 100644
> > --- a/lib/actions.c
> > +++ b/lib/actions.c
> > @@ -371,12 +371,35 @@ ovnact_next_free(struct ovnact_next *a OVS_UNUSED)
> >  {
> >  }
> >
> > +static bool
> > +check_ovnfield_load(struct action_context *ctx, const struct expr_field *field)
> > +{
> > +    switch (field->symbol->ovn_field->id) {
> > +    case OVN_ICMP4_FRAG_MTU:
> > +    case OVN_ICMP6_FRAG_MTU:
> > +        return true;
> > +
> > +    case OVN_IP_SRC:
> > +    case OVN_IP_DST:
> > +        lexer_error(ctx->lexer, "Can't load a value to ovn field (%s).",
> > +                    field->symbol->name);
> > +        return false;
> > +
> > +    case OVN_FIELD_N_IDS:
> > +    default:
> > +        OVS_NOT_REACHED();
> > +    }
> > +}
> > +
> >  static void
> >  parse_LOAD(struct action_context *ctx, const struct expr_field *lhs)
> >  {
> >      size_t ofs = ctx->ovnacts->size;
> >      struct ovnact_load *load;
> >      if (lhs->symbol->ovn_field) {
> > +        if (!check_ovnfield_load(ctx, lhs)) {
> > +            return;
> > +        }
> >          load = ovnact_put_OVNFIELD_LOAD(ctx->ovnacts);
> >      } else {
> >          load = ovnact_put_LOAD(ctx->ovnacts);
> > @@ -474,6 +497,46 @@ format_EXCHANGE(const struct ovnact_move *move, struct ds *s)
> >      format_assignment(move, "<->", s);
> >  }
> >
> > +static void
> > +parse_ovnfield_exchange(struct action_context *ctx,
> > +                        const struct expr_field *lhs,
> > +                        const struct expr_field *rhs)
> > +{
> > +    if (!lhs->symbol->ovn_field || !rhs->symbol->ovn_field) {
> > +        lexer_error(ctx->lexer,
> > +                    "Can't exchange ovn field with non ovn field (%s <-> %s).",
> > +                    lhs->symbol->name, rhs->symbol->name);
> > +        return;
> > +    }
> > +
> > +    if (lhs->symbol->ovn_field->id != OVN_IP_SRC &&
> > +            lhs->symbol->ovn_field->id != OVN_IP_DST) {
> > +        lexer_error(ctx->lexer,
> > +                    "Can't exchange ovn field (%s) with ovn field (%s).",
> > +                    lhs->symbol->name, rhs->symbol->name);
> > +        return;
> > +    }
> > +
> > +    if (rhs->symbol->ovn_field->id != OVN_IP_SRC &&
> > +            rhs->symbol->ovn_field->id != OVN_IP_DST) {
> > +        lexer_error(ctx->lexer,
> > +                    "Can't exchange ovn field (%s) with ovn field (%s).",
> > +                    lhs->symbol->name, rhs->symbol->name);
> > +        return;
> > +    }
> > +
> > +    if (lhs->symbol->ovn_field->id == rhs->symbol->ovn_field->id) {
> > +        lexer_error(ctx->lexer,
> > +                    "Can't exchange ovn field (%s) with ovn field (%s).",
> > +                    lhs->symbol->name, rhs->symbol->name);
> > +        return;
> > +    }
> > +
> > +    struct ovnact_move *move = ovnact_put_OVNFIELD_EXCHANGE(ctx->ovnacts);
> > +    move->lhs = *lhs;
> > +    move->rhs = *rhs;
> > +}
> > +
> >  static void
> >  parse_assignment_action(struct action_context *ctx, bool exchange,
> >                          const struct expr_field *lhs)
> > @@ -483,6 +546,11 @@ parse_assignment_action(struct action_context *ctx, bool exchange,
> >          return;
> >      }
> >
> > +    if (exchange && (lhs->symbol->ovn_field || rhs.symbol->ovn_field)) {
> > +        parse_ovnfield_exchange(ctx, lhs, &rhs);
> > +        return;
> > +    }
> > +
> >      const struct expr_symbol *ls = lhs->symbol;
> >      const struct expr_symbol *rs = rhs.symbol;
> >      if ((ls->width != 0) != (rs->width != 0)) {
> > @@ -3128,6 +3196,8 @@ format_OVNFIELD_LOAD(const struct ovnact_load *load , struct ds *s)
> >                        ntohs(load->imm.value.be16_int));
> >          break;
> >
> > +    case OVN_IP_SRC:
> > +    case OVN_IP_DST:
> >      case OVN_FIELD_N_IDS:
> >      default:
> >          OVS_NOT_REACHED();
> > @@ -3157,6 +3227,9 @@ encode_OVNFIELD_LOAD(const struct ovnact_load *load,
> >          encode_finish_controller_op(oc_offset, ofpacts);
> >          break;
> >      }
> > +
> > +    case OVN_IP_SRC:
> > +    case OVN_IP_DST:
> >      case OVN_FIELD_N_IDS:
> >      default:
> >          OVS_NOT_REACHED();
> > @@ -3451,6 +3524,51 @@ ovnact_fwd_group_free(struct ovnact_fwd_group *fwd_group)
> >      free(fwd_group->child_ports);
> >  }
> >
> > +static void
> > +format_OVNFIELD_EXCHANGE(const struct ovnact_move *move , struct ds *s)
> > +{
> > +    const struct ovn_field *lhs = ovn_field_from_name(move->lhs.symbol->name);
> > +    const struct ovn_field *rhs = ovn_field_from_name(move->rhs.symbol->name);
> > +    switch (lhs->id) {
> > +    case OVN_IP_SRC:
> > +    case OVN_IP_DST:
> > +        break;
> > +
> > +    case OVN_ICMP4_FRAG_MTU:
> > +    case OVN_ICMP6_FRAG_MTU:
> > +    case OVN_FIELD_N_IDS:
> > +    default:
> > +        OVS_NOT_REACHED();
> > +    }
>
> Nit: I would use the shorter:
> ovs_asssert(lhs->id == OVN_IP_SRC || lhs->id == OVN_IP_DST);

You mean to drop the switch right ? If so, Ack.


>
> > +
> > +    switch (rhs->id) {
> > +    case OVN_IP_SRC:
> > +    case OVN_IP_DST:
> > +        break;
> > +
> > +    case OVN_ICMP4_FRAG_MTU:
> > +    case OVN_ICMP6_FRAG_MTU:
> > +    case OVN_FIELD_N_IDS:
> > +    default:
> > +        OVS_NOT_REACHED();
> > +    }
>
> Nit: I would use the shorter:
> ovs_asssert(rhs->id == OVN_IP_SRC || rhs->id == OVN_IP_DST);
>
> > +
> > +    ds_put_format(s, "%s <-> %s;", lhs->name, rhs->name);
> > +}
> > +
> > +static void
> > +encode_OVNFIELD_EXCHANGE(const struct ovnact_move *move OVS_UNUSED,
> > +                         const struct ovnact_encode_params *ep OVS_UNUSED,
> > +                         struct ofpbuf *ofpacts OVS_UNUSED)
> > +{
> > +    /* Right now we only support exchanging the IPs in
> > +     * OVN fields (ip.src <-> ip.dst). */
> > +    size_t oc_offset =
> > +        encode_start_controller_op(ACTION_OPCODE_SWAP_SRC_DST_IP,
> > +                                   true, NX_CTLR_NO_METER, ofpacts);
> > +    encode_finish_controller_op(oc_offset, ofpacts);
>
> I think this means that all packets matching a flow with action "reject { ...
> ip.src <-> ip.dst ... }" will generate two packet-ins, right? One for the
> reject action, one for the ovnfield-exchange action.
>
> Is that a concern wrt. performance?

Yes. It would have 2 packet-ins. Just like how we handle - icmp4 {...
icmp4.frag_mtu = 1500; ...};

If performance is a concern, we could just drop ... ip.src <-> ip.dst
in reject and let reject action
swap the ip src with ip destination. I thought about that and my take
is that since reject { } results in
TCP RST or ICMP unreachable packet, it should be fine. I see these
packets as more of control packets.

I think it should be ok. Let me know what you think.


>
> > +}
> > +
> >  /* Parses an assignment or exchange or put_dhcp_opts action. */
> >  static void
> >  parse_set_action(struct action_context *ctx)
> > diff --git a/lib/logical-fields.c b/lib/logical-fields.c
> > index bf61df7719..d6f1981f52 100644
> > --- a/lib/logical-fields.c
> > +++ b/lib/logical-fields.c
> > @@ -33,6 +33,14 @@ const struct ovn_field ovn_fields[OVN_FIELD_N_IDS] = {
> >          OVN_ICMP6_FRAG_MTU,
> >          "icmp6.frag_mtu",
> >          4, 32,
> > +    }, {
> > +        OVN_IP_SRC,
> > +        "ip.src",
> > +        16, 128,
> > +    }, {
> > +        OVN_IP_DST,
> > +        "ip.dst",
> > +        16, 128,
>
> Just partially related to your change, I'm a bit confused by the meaning of
> n_bytes and n_bits in "struct ovn_field".  It seems to me that we never use
> those values.  Is that the case or am I missing something?

These OVN fields are defined more like the way - mf_fields are defined.
Like icmp4.frag_mtu is 2 bytes and 16 bits field.

So ip.src/ip.dst can be used for both ipv4 and ipv6, I have set the
size of ipv6.

Since we don't support ip.src = 10.0.0.4 or ip.src = aef00::4 for
example, these fields
are not used. Later on if there is a need to support assigning a value
to these fields, these fields
could be used. Although I don't see a need to support it since we
already have ip4.src/ip


Thanks for the review.

Numan

>


> Thanks,
> Dumitru
>
> >      },
> >  };
> >
> > @@ -271,6 +279,8 @@ ovn_init_symtab(struct shash *symtab)
> >
> >      expr_symtab_add_ovn_field(symtab, "icmp4.frag_mtu", OVN_ICMP4_FRAG_MTU);
> >      expr_symtab_add_ovn_field(symtab, "icmp6.frag_mtu", OVN_ICMP6_FRAG_MTU);
> > +    expr_symtab_add_ovn_field(symtab, "ip.src", OVN_IP_SRC);
> > +    expr_symtab_add_ovn_field(symtab, "ip.dst", OVN_IP_DST);
> >  }
> >
> >  const char *
> > diff --git a/ovn-sb.xml b/ovn-sb.xml
> > index 2fc84f54ee..73ee543bfe 100644
> > --- a/ovn-sb.xml
> > +++ b/ovn-sb.xml
> > @@ -1258,6 +1258,43 @@
> >              except that the two values are exchanged instead of copied.  Both
> >              <var>field1</var> and <var>field2</var> must modifiable.
> >            </p>
> > +
> > +          <p>
> > +            <code>OVN</code> supports exchange of below OVN logical fields.
> > +          </p>
> > +
> > +          <ul>
> > +            <li>
> > +              <code>ip.src</code>
> > +              <code>ip.dst</code>
> > +              <p>
> > +                These fields can be used to refer to IP source and destination
> > +                fields which are IP version independent. These fields can be
> > +                used only for exchange of values.
> > +              </p>
> > +            </li>
> > +
> > +            <li>
> > +              <p>
> > +                Below are few examples:
> > +              </p>
> > +
> > +              <p>
> > +                match = "ip && tcp"
> > +                action = "ip.src <-> ip.dst; next;"
> > +              </p>
> > +
> > +              <p>
> > +                match = "ip4 || ip6"
> > +                action = reject { ip.src <-> ip.dst; } next;"
> > +              </p>
> > +
> > +              <p>
> > +                match = "ip && (tcp || udp)"
> > +                action = "ip.src <-> ip.dst; next;"
> > +              </p>
> > +            </li>
> > +          </ul>
> >          </dd>
> >
> >          <dt><code>ip.ttl--;</code></dt>
> > diff --git a/tests/ovn.at b/tests/ovn.at
> > index 71837a6721..c40d69c5e9 100644
> > --- a/tests/ovn.at
> > +++ b/tests/ovn.at
> > @@ -1605,6 +1605,33 @@ reject { };
> >      formats as reject { drop; };
> >      encodes as controller(userdata=00.00.00.16.00.00.00.00)
> >
> > +ip.src <-> ip.dst;
> > +    encodes as controller(userdata=00.00.00.17.00.00.00.00,pause)
> > +
> > +ip.src <-> ip.dst
> > +    Syntax error at end of input expecting `;'.
> > +
> > +ip.src = 10.0.0.10;
> > +    Can't load a value to ovn field (ip.src).
> > +
> > +ip.dst = aef0::4;
> > +    Can't load a value to ovn field (ip.dst).
> > +
> > +ip.src <-> ip4.dst;
> > +    Can't exchange ovn field with non ovn field (ip.src <-> ip4.dst).
> > +
> > +ip6.src <-> ip.dst;
> > +    Can't exchange ovn field with non ovn field (ip6.src <-> ip.dst).
> > +
> > +ip.src <-> icmp4.frag_mtu;
> > +    Can't exchange ovn field (ip.src) with ovn field (icmp4.frag_mtu).
> > +
> > +icmp6.frag_mtu <-> ip.dst;
> > +    Can't exchange ovn field (icmp6.frag_mtu) with ovn field (ip.dst).
> > +
> > +ip.src <-> ip.src;
> > +    Can't exchange ovn field (ip.src) with ovn field (ip.src).
> > +
> >  # trigger_event
> >  trigger_event(event = "empty_lb_backends", vip = "10.0.0.1:80", protocol = "tcp", load_balancer = "12345678-abcd-9876-fedc-11119f8e7d6c");
> >      encodes as controller(userdata=00.00.00.0f.00.00.00.00.00.00.00.00.00.01.00.0b.31.30.2e.30.2e.30.2e.31.3a.38.30.00.02.00.03.74.63.70.00.03.00.24.31.32.33.34.35.36.37.38.2d.61.62.63.64.2d.39.38.37.36.2d.66.65.64.63.2d.31.31.31.31.39.66.38.65.37.64.36.63)
> > diff --git a/utilities/ovn-trace.c b/utilities/ovn-trace.c
> > index 38aee6081b..ed7d8bf278 100644
> > --- a/utilities/ovn-trace.c
> > +++ b/utilities/ovn-trace.c
> > @@ -2147,12 +2147,35 @@ execute_ovnfield_load(const struct ovnact_load *load,
> >                               ntohs(load->imm.value.be16_int));
> >          break;
> >      }
> > +
> > +    case OVN_IP_SRC:
> > +    case OVN_IP_DST:
> >      case OVN_FIELD_N_IDS:
> >      default:
> >          OVS_NOT_REACHED();
> >      }
> >  }
> >
> > +static void
> > +execute_ovnfield_exchange(const struct ovnact_move *move OVS_UNUSED,
> > +                          struct flow *uflow,
> > +                          struct ovs_list *super)
> > +{
> > +    /* Right now we support exchanging of ip.src with ip.dst. */
> > +    ovntrace_node_append(super, OVNTRACE_NODE_MODIFY,
> > +                         "ip.src <-> ip.dst");
> > +
> > +    if (get_dl_type(uflow) == htons(ETH_TYPE_IP)) {
> > +        ovs_be32 tmp = uflow->nw_dst;
> > +        uflow->nw_dst = uflow->nw_src;
> > +        uflow->nw_src = tmp;
> > +    } else {
> > +        struct in6_addr tmp = uflow->ipv6_dst;
> > +        uflow->ipv6_dst = uflow->ipv6_src;
> > +        uflow->ipv6_src = tmp;
> > +    }
> > +}
> > +
> >  static void
> >  trace_actions(const struct ovnact *ovnacts, size_t ovnacts_len,
> >                const struct ovntrace_datapath *dp, struct flow *uflow,
> > @@ -2369,6 +2392,11 @@ trace_actions(const struct ovnact *ovnacts, size_t ovnacts_len,
> >                             pipeline, super);
> >              break;
> >
> > +        case OVNACT_OVNFIELD_EXCHANGE:
> > +            execute_ovnfield_exchange(ovnact_get_OVNFIELD_EXCHANGE(a),
> > +                                      uflow, super);
> > +            break;
> > +
> >          case OVNACT_TRIGGER_EVENT:
> >              break;
> >
> >
>
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