[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 12:38:25 UTC 2020


On Wed, Oct 14, 2020 at 5:51 PM Dumitru Ceara <dceara at redhat.com> wrote:
>
> On 10/14/20 2:13 PM, Numan Siddique wrote:
> > On Wed, Oct 14, 2020 at 5:34 PM Dumitru Ceara <dceara at redhat.com> wrote:
> >>
> >> On 10/14/20 1:54 PM, Numan Siddique wrote:
> >>> On Wed, Oct 14, 2020 at 4:40 PM Dumitru Ceara <dceara at redhat.com> wrote:
> >>>>
> >>>> On 10/14/20 12:50 PM, Numan Siddique wrote:
> >>>>> 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.
> >>>>>
> >>>>
> >>>> Right, I meant ovs_assert instead of switch.
> >>>>
> >>>>>
> >>>>>>
> >>>>>>> +
> >>>>>>> +    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.
> >>>>>
> >>>>
> >>>> I think I like the approach of "reject" action implicitly swapping IPs best.
> >>>> In the end it's not like we could implement reject withough swapping IP dst
> >>>> with IP src so why not do it as part of the reject action.
> >>>>
> >>>
> >>> Agree. reject action is expected to be used to send the generated tcp
> >>> rst/icmp unreachable
> >>> packet back to the sender.
> >>>
> >>> I'm ok to change the reject action to just swap the IPs internally if
> >>> everyone is fine.
> >>>
> >>> @Mark Michelson  @Han Zhou  Do you have any comments here ?
> >>>
> >>> Option 1 - reject { ...}    -> The reject action handling in pinctrl.c
> >>> will swap the ip source and destination
> >>>
> >>> Option 2: reject {... ip.src <-> ip.dst ...} which is the proposed
> >>> approach in this patch series. This results in
> >>> 2 packet-ins.
> >>>
> >>> I personally prefer (2) since in OVN we normally tell what inner
> >>> actions to apply for many OVN actions.
> >>> But I have no strong preference and I'm fine changing to (1).
> >>>
> >>> If we chose option (1), we could add a comment inside the action like
> >>> - reject { /* ip.src <-> ip.dst is done implicitly*/,  eth.src <->
> >>> eth.dst; output ; }
> >>>
> >>
> >> Then, why not swap ETH addresses implicitly too?
> >
> > As I mentioned above, I'd prefer if ovn-northd says what actions to
> > apply for the reject
> > packet. Just like for icmp4 or arp actions, ovn-northd says what
> > actions to apply for the
> > transformed packet from the source packet.
> >
>
> I was thinking that if we go this way when we build the packet in
> ovn-controller it might look weird to a reader of the pinctrl code to see
> something like:
>
> /* We only swap IPs because ETH addresses are swapped in OVS. */
> pinctrl_compose_ipv4(&packet, ip_flow->dl_src, ip_flow->dl_dst,
>                      ip_flow->nw_dst, ip_flow->nw_src, ...)

Right. I agree. It makes sense to swap both eth and ip if we go this
way. Sorry for the confusion.

Thanks
Numan

>
> Regards,
> Dumitru
>
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