[ovs-dev] [PATCH ovn 1/4] ovn-controller: A new action "select".

Numan Siddique numans at ovn.org
Fri Jan 17 12:38:29 UTC 2020


On Tue, Jan 7, 2020 at 8:00 AM Han Zhou <hzhou at ovn.org> wrote:
>
> Support a new logical flow action "select", which can be used to
> implement features such as ECMP.  The action uses OpenFlow group
> action to select an integer (uint16_t) from a list of integers,
> and assign it to specified field, e.g.:
>     select(reg0, 1, 2, 3)
> A weight can be specified for each member as well, e.g.:
>     select(reg0, 1=20, 2=30, 3=50)
>
> Signed-off-by: Han Zhou <hzhou at ovn.org>


Hi Han,

The overall series LGTM. I have one comment on the action "select".
We already have existing actions  like put_dhcp_opts (and others)
which store the result to a register.
I think it would be better to use it in similar way i.e "reg0 =
select(1:20, 2:30, 3:50)".

Also instead of "=" I would suggest to use ":" to store the weight.

Thanks
Numan



> ---
>  include/ovn/actions.h     |  15 +++++
>  lib/actions.c             | 142 ++++++++++++++++++++++++++++++++++++++++++++--
>  ovn-sb.xml                |  31 ++++++++++
>  tests/ovn.at              |  26 +++++++++
>  tests/test-ovn.c          |  26 ++++++++-
>  utilities/ovn-trace.8.xml |   9 +++
>  utilities/ovn-trace.c     |  66 ++++++++++++++++++++-
>  7 files changed, 308 insertions(+), 7 deletions(-)
>
> diff --git a/include/ovn/actions.h b/include/ovn/actions.h
> index 047a8d7..2d4b05b 100644
> --- a/include/ovn/actions.h
> +++ b/include/ovn/actions.h
> @@ -61,6 +61,7 @@ struct ovn_extend_table;
>      OVNACT(CT_DNAT,           ovnact_ct_nat)          \
>      OVNACT(CT_SNAT,           ovnact_ct_nat)          \
>      OVNACT(CT_LB,             ovnact_ct_lb)           \
> +    OVNACT(SELECT,            ovnact_select)          \
>      OVNACT(CT_CLEAR,          ovnact_null)            \
>      OVNACT(CLONE,             ovnact_nest)            \
>      OVNACT(ARP,               ovnact_nest)            \
> @@ -251,6 +252,20 @@ struct ovnact_ct_lb {
>      uint8_t ltable;             /* Logical table ID of next table. */
>  };
>
> +struct ovnact_select_dst {
> +    uint16_t id;
> +    uint16_t weight;
> +};
> +
> +/* OVNACT_SELECT. */
> +struct ovnact_select {
> +    struct ovnact ovnact;
> +    struct ovnact_select_dst *dsts;
> +    size_t n_dsts;
> +    uint8_t ltable;             /* Logical table ID of next table. */
> +    struct expr_field res_field;
> +};
> +
>  /* OVNACT_ARP, OVNACT_ND_NA, OVNACT_CLONE. */
>  struct ovnact_nest {
>      struct ovnact ovnact;
> diff --git a/lib/actions.c b/lib/actions.c
> index 051e6c8..b05e1f2 100644
> --- a/lib/actions.c
> +++ b/lib/actions.c
> @@ -218,17 +218,18 @@ action_parse_field(struct action_context *ctx,
>  }
>
>  static bool
> -action_parse_port(struct action_context *ctx, uint16_t *port)
> +action_parse_uint16(struct action_context *ctx, uint16_t *_value,
> +                    const char *msg)
>  {
>      if (lexer_is_int(ctx->lexer)) {
>          int value = ntohll(ctx->lexer->token.value.integer);
>          if (value <= UINT16_MAX) {
> -            *port = value;
> +            *_value = value;
>              lexer_get(ctx->lexer);
>              return true;
>          }
>      }
> -    lexer_syntax_error(ctx->lexer, "expecting port number");
> +    lexer_syntax_error(ctx->lexer, "expecting %s", msg);
>      return false;
>  }
>
> @@ -927,7 +928,7 @@ parse_ct_lb_action(struct action_context *ctx)
>                  }
>                  dst.port = 0;
>                  if (lexer_match(ctx->lexer, LEX_T_COLON)
> -                    && !action_parse_port(ctx, &dst.port)) {
> +                    && !action_parse_uint16(ctx, &dst.port, "port number")) {
>                      free(dsts);
>                      return;
>                  }
> @@ -957,7 +958,8 @@ parse_ct_lb_action(struct action_context *ctx)
>                          lexer_syntax_error(ctx->lexer, "IPv6 address needs "
>                                  "square brackets if port is included");
>                          return;
> -                    } else if (!action_parse_port(ctx, &dst.port)) {
> +                    } else if (!action_parse_uint16(ctx, &dst.port,
> +                                                    "port number")) {
>                          free(dsts);
>                          return;
>                      }
> @@ -1099,6 +1101,134 @@ ovnact_ct_lb_free(struct ovnact_ct_lb *ct_lb)
>  }
>
>  static void
> +parse_select_action(struct action_context *ctx)
> +{
> +    if (ctx->pp->cur_ltable >= ctx->pp->n_tables) {
> +        lexer_error(ctx->lexer,
> +                    "\"select\" action not allowed in last table.");
> +        return;
> +    }
> +
> +    struct ovnact_select_dst *dsts = NULL;
> +    size_t allocated_dsts = 0;
> +    size_t n_dsts = 0;
> +
> +    if (!lexer_match(ctx->lexer, LEX_T_LPAREN)) {
> +        lexer_syntax_error(ctx->lexer, "expecting '('");
> +        return;
> +    }
> +
> +    /* parse the result field */
> +    struct expr_field res_field;
> +    if (!expr_field_parse(ctx->lexer, ctx->pp->symtab, &res_field,
> +                          &ctx->prereqs)) {
> +        return;
> +    }
> +    if (!lexer_match(ctx->lexer, LEX_T_COMMA)) {
> +        lexer_syntax_error(ctx->lexer, "expecting ','");
> +        return;
> +    }
> +
> +    while (!lexer_match(ctx->lexer, LEX_T_RPAREN)) {
> +        struct ovnact_select_dst dst;
> +        if (!action_parse_uint16(ctx, &dst.id, "id")) {
> +            free(dsts);
> +            return;
> +        }
> +
> +        dst.weight = 0;
> +        if (lexer_match(ctx->lexer, LEX_T_EQUALS)) {
> +            if (!action_parse_uint16(ctx, &dst.weight, "weight")) {
> +                free(dsts);
> +                return;
> +            }
> +            if (dst.weight == 0) {
> +                lexer_syntax_error(ctx->lexer, "weight can't be 0");
> +            }
> +        }
> +        lexer_match(ctx->lexer, LEX_T_COMMA);
> +
> +        /* Append to dsts. */
> +        if (n_dsts >= allocated_dsts) {
> +            dsts = x2nrealloc(dsts, &allocated_dsts, sizeof *dsts);
> +        }
> +        dsts[n_dsts++] = dst;
> +    }
> +    if (n_dsts <= 1) {
> +        lexer_syntax_error(ctx->lexer, "expecting at least 2 group members");
> +        return;
> +    }
> +
> +    struct ovnact_select *sn = ovnact_put_SELECT(ctx->ovnacts);
> +    sn->ltable = ctx->pp->cur_ltable + 1;
> +    sn->dsts = dsts;
> +    sn->n_dsts = n_dsts;
> +    sn->res_field = res_field;
> +}
> +
> +static void
> +format_SELECT(const struct ovnact_select *sn, struct ds *s)
> +{
> +    ds_put_cstr(s, "select");
> +    ds_put_char(s, '(');
> +    expr_field_format(&sn->res_field, s);
> +    ds_put_cstr(s, ", ");
> +    for (size_t i = 0; i < sn->n_dsts; i++) {
> +        if (i) {
> +            ds_put_cstr(s, ", ");
> +        }
> +
> +        const struct ovnact_select_dst *dst = &sn->dsts[i];
> +        ds_put_format(s, "%"PRIu16, dst->id);
> +        ds_put_format(s, "=%"PRIu16, dst->weight ? dst->weight : 100);
> +    }
> +    ds_put_char(s, ')');
> +    ds_put_char(s, ';');
> +}
> +
> +static void
> +encode_SELECT(const struct ovnact_select *sn,
> +             const struct ovnact_encode_params *ep,
> +             struct ofpbuf *ofpacts)
> +{
> +    ovs_assert(sn->n_dsts >= 1);
> +    uint8_t resubmit_table = sn->ltable + first_ptable(ep, ep->pipeline);
> +    uint32_t table_id = 0;
> +    struct ofpact_group *og;
> +
> +    struct ds ds = DS_EMPTY_INITIALIZER;
> +    ds_put_format(&ds, "type=select,selection_method=dp_hash");
> +
> +    struct mf_subfield sf = expr_resolve_field(&sn->res_field);
> +
> +    for (size_t bucket_id = 0; bucket_id < sn->n_dsts; bucket_id++) {
> +        const struct ovnact_select_dst *dst = &sn->dsts[bucket_id];
> +        ds_put_format(&ds, ",bucket=bucket_id=%"PRIuSIZE",weight:%"PRIu16
> +                      ",actions=", bucket_id, dst->weight ? dst->weight : 100);
> +        ds_put_format(&ds, "load:%u->%s[%u..%u],", dst->id, sf.field->name,
> +                      sf.ofs, sf.ofs + sf.n_bits - 1);
> +        ds_put_format(&ds, "resubmit(,%d)", resubmit_table);
> +    }
> +
> +    table_id = ovn_extend_table_assign_id(ep->group_table, ds_cstr(&ds),
> +                                          ep->lflow_uuid);
> +    ds_destroy(&ds);
> +    if (table_id == EXT_TABLE_ID_INVALID) {
> +        return;
> +    }
> +
> +    /* Create an action to set the group. */
> +    og = ofpact_put_GROUP(ofpacts);
> +    og->group_id = table_id;
> +}
> +
> +static void
> +ovnact_select_free(struct ovnact_select *select)
> +{
> +    free(select->dsts);
> +}
> +
> +static void
>  format_CT_CLEAR(const struct ovnact_null *null OVS_UNUSED, struct ds *s)
>  {
>      ds_put_cstr(s, "ct_clear;");
> @@ -2931,6 +3061,8 @@ parse_action(struct action_context *ctx)
>          parse_CT_SNAT(ctx);
>      } else if (lexer_match_id(ctx->lexer, "ct_lb")) {
>          parse_ct_lb_action(ctx);
> +    } else if (lexer_match_id(ctx->lexer, "select")) {
> +        parse_select_action(ctx);
>      } else if (lexer_match_id(ctx->lexer, "ct_clear")) {
>          ovnact_put_CT_CLEAR(ctx->ovnacts);
>      } else if (lexer_match_id(ctx->lexer, "clone")) {
> diff --git a/ovn-sb.xml b/ovn-sb.xml
> index 82167c4..4501df1 100644
> --- a/ovn-sb.xml
> +++ b/ovn-sb.xml
> @@ -2114,6 +2114,37 @@ tcp.flags = RST;
>
>            <p><b>Example:</b> <code>handle_svc_check(inport);</code></p>
>          </dd>
> +
> +        <dt><code>select(<var>R</var>, <var>N1</var>[=<var>W1</var>], <var>N2</var>[=<var>W2</var>], ...);</code></dt>
> +        <dd>
> +          <p>
> +            <b>Parameters</b>: logical field or subfield <var>R</var>. Integer
> +              <var>N1</var>, <var>N2</var>..., with optional weight <var>W1</var>,
> +              <var>W2</var>, ...
> +          </p>
> +
> +          <p>
> +            Select from a list of integers <var>N1</var>, <var>N2</var>...,
> +            each within the range 0 ~ 65535, and store the selected one in the
> +            field <var>R</var>.  There must be 2 or more integers listed, each
> +            with an optional weight, which is an integer within the range 1 ~
> +            65535.  If weight is not specified, it defaults to 100. The
> +            selection method is based on the 5-tuple hash of packet header.
> +          </p>
> +
> +          <p>
> +            Processing automatically moves on to the next table, as if
> +            <code>next;</code> were specified.  The <code>select</code> action
> +            must be put as the last action of the logical flow when there are
> +            multiple actions (actions put after <code>select</code> will not
> +            take effect).
> +          </p>
> +
> +          <p>
> +            <b>Example:</b> <code>select(reg8[16..31], 1=20, 2=30, 3=50);</code>
> +          </p>
> +        </dd>
> +
>        </dl>
>      </column>
>
> diff --git a/tests/ovn.at b/tests/ovn.at
> index 411b768..3050289 100644
> --- a/tests/ovn.at
> +++ b/tests/ovn.at
> @@ -965,14 +965,17 @@ ct_lb();
>      has prereqs ip
>  ct_lb(192.168.1.2:80, 192.168.1.3:80);
>      encodes as group:1
> +    uses group: id(1), name(type=select,selection_method=dp_hash,bucket=bucket_id=0,weight:100,actions=ct(nat(dst=192.168.1.2:80),commit,table=19,zone=NXM_NX_REG13[0..15]),bucket=bucket_id=1,weight:100,actions=ct(nat(dst=192.168.1.3:80),commit,table=19,zone=NXM_NX_REG13[0..15]))
>      has prereqs ip
>  ct_lb(192.168.1.2, 192.168.1.3, );
>      formats as ct_lb(192.168.1.2, 192.168.1.3);
>      encodes as group:2
> +    uses group: id(2), name(type=select,selection_method=dp_hash,bucket=bucket_id=0,weight:100,actions=ct(nat(dst=192.168.1.2),commit,table=19,zone=NXM_NX_REG13[0..15]),bucket=bucket_id=1,weight:100,actions=ct(nat(dst=192.168.1.3),commit,table=19,zone=NXM_NX_REG13[0..15]))
>      has prereqs ip
>  ct_lb(fd0f::2, fd0f::3, );
>      formats as ct_lb(fd0f::2, fd0f::3);
>      encodes as group:3
> +    uses group: id(3), name(type=select,selection_method=dp_hash,bucket=bucket_id=0,weight:100,actions=ct(nat(dst=fd0f::2),commit,table=19,zone=NXM_NX_REG13[0..15]),bucket=bucket_id=1,weight:100,actions=ct(nat(dst=fd0f::3),commit,table=19,zone=NXM_NX_REG13[0..15]))
>      has prereqs ip
>
>  ct_lb(192.168.1.2:);
> @@ -1481,6 +1484,29 @@ handle_svc_check();
>  handle_svc_check(reg0);
>      Cannot use numeric field reg0 where string field is required.
>
> +# select
> +select(reg9[16..31],1=50, 2=100, 3, );
> +    formats as select(reg9[16..31], 1=50, 2=100, 3=100);
> +    encodes as group:4
> +    uses group: id(4), name(type=select,selection_method=dp_hash,bucket=bucket_id=0,weight:50,actions=load:1->xreg4[16..31],resubmit(,19),bucket=bucket_id=1,weight:100,actions=load:2->xreg4[16..31],resubmit(,19),bucket=bucket_id=2,weight:100,actions=load:3->xreg4[16..31],resubmit(,19))
> +select(reg0,1, 2);
> +    formats as select(reg0, 1=100, 2=100);
> +    encodes as group:5
> +    uses group: id(5), name(type=select,selection_method=dp_hash,bucket=bucket_id=0,weight:100,actions=load:1->xxreg0[96..127],resubmit(,19),bucket=bucket_id=1,weight:100,actions=load:2->xxreg0[96..127],resubmit(,19))
> +
> +select(1, 2);
> +    Syntax error at `1' expecting field name.
> +select(reg0, 1=, 2);
> +    Syntax error at `,' expecting weight.
> +select(reg0, 1=0, 2);
> +    Syntax error at `,' weight can't be 0.
> +select(reg0, 1=123456, 2);
> +    Syntax error at `123456' expecting weight.
> +select(reg0, 123);
> +    Syntax error at `;' expecting at least 2 group members.
> +select(reg0);
> +    Syntax error at `)' expecting ','.
> +
>  # Miscellaneous negative tests.
>  ;
>      Syntax error at `;'.
> diff --git a/tests/test-ovn.c b/tests/test-ovn.c
> index 5366905..476bc33 100644
> --- a/tests/test-ovn.c
> +++ b/tests/test-ovn.c
> @@ -1227,6 +1227,28 @@ test_expr_to_packets(struct ovs_cmdl_context *ctx OVS_UNUSED)
>  /* Actions. */
>
>  static void
> +print_group_info(struct ovn_extend_table *group_table, const char *action)
> +{
> +    struct ovn_extend_table_info *g;
> +    HMAP_FOR_EACH (g, hmap_node, &group_table->desired) {
> +        char buf[64];
> +        sprintf(buf, "group:%"PRIu32, g->table_id);
> +        char *match = strstr(buf, action);
> +        if (match) {
> +            if (match[strlen(buf)] != '\0') {
> +                /* Add ',' and match again. */
> +                sprintf(buf, "group:%"PRIu32",", g->table_id);
> +                match = strstr(buf, action);
> +            }
> +        }
> +        if (match) {
> +            printf("    uses group: id(%"PRIu32"), name(%s)\n",
> +                   g->table_id, g->name);
> +        }
> +    }
> +}
> +
> +static void
>  test_parse_actions(struct ovs_cmdl_context *ctx OVS_UNUSED)
>  {
>      struct shash symtab;
> @@ -1305,7 +1327,9 @@ test_parse_actions(struct ovs_cmdl_context *ctx OVS_UNUSED)
>              struct ds ofpacts_s = DS_EMPTY_INITIALIZER;
>              struct ofpact_format_params fp = { .s = &ofpacts_s };
>              ofpacts_format(ofpacts.data, ofpacts.size, &fp);
> -            printf("    encodes as %s\n", ds_cstr(&ofpacts_s));
> +            char *ofpacts_cstr = ds_cstr(&ofpacts_s);
> +            printf("    encodes as %s\n", ofpacts_cstr);
> +            print_group_info(&group_table, ofpacts_cstr);
>              ds_destroy(&ofpacts_s);
>              ofpbuf_uninit(&ofpacts);
>
> diff --git a/utilities/ovn-trace.8.xml b/utilities/ovn-trace.8.xml
> index 01e7411..485928c 100644
> --- a/utilities/ovn-trace.8.xml
> +++ b/utilities/ovn-trace.8.xml
> @@ -438,6 +438,15 @@
>        <code>--lb-dst</code> is not available in daemon mode.
>      </dd>
>
> +    <dt><code>--select-id=</code><var>id</var></dt>
> +    <dd>
> +      Specify the <var>id</var> to be selected by the <code>select</code>
> +      action. <var>id</var> must be one of the values listed in the
> +      <code>select</code> action.  Otherwise, a random id is selected from
> +      the list, as if <code>--select-id</code> were not specified.
> +      <code>--select-id</code> is not available in daemon mode.
> +    </dd>
> +
>      <dt><code>--friendly-names</code></dt>
>      <dt><code>--no-friendly-names</code></dt>
>      <dd>
> diff --git a/utilities/ovn-trace.c b/utilities/ovn-trace.c
> index 2645438..a97195b 100644
> --- a/utilities/ovn-trace.c
> +++ b/utilities/ovn-trace.c
> @@ -81,6 +81,9 @@ static size_t ct_state_idx;
>  /* --lb-dst: load balancer destination info. */
>  static struct ovnact_ct_lb_dst lb_dst;
>
> +/* --select-id: "select" action member id. */
> +static uint16_t select_id;
> +
>  /* --friendly-names, --no-friendly-names: Whether to substitute human-friendly
>   * port and datapath names for the awkward UUIDs typically used in the actual
>   * logical flows. */
> @@ -209,6 +212,16 @@ parse_lb_option(const char *s)
>  }
>
>  static void
> +parse_select_option(const char *s)
> +{
> +    unsigned long int integer = strtoul(s, NULL, 10);
> +    if (!integer) {
> +        ovs_fatal(0, "%s: bad select-id", s);
> +    }
> +    select_id = integer;
> +}
> +
> +static void
>  parse_options(int argc, char *argv[])
>  {
>      enum {
> @@ -225,7 +238,8 @@ parse_options(int argc, char *argv[])
>          DAEMON_OPTION_ENUMS,
>          SSL_OPTION_ENUMS,
>          VLOG_OPTION_ENUMS,
> -        OPT_LB_DST
> +        OPT_LB_DST,
> +        OPT_SELECT_ID
>      };
>      static const struct option long_options[] = {
>          {"db", required_argument, NULL, OPT_DB},
> @@ -241,6 +255,7 @@ parse_options(int argc, char *argv[])
>          {"help", no_argument, NULL, 'h'},
>          {"version", no_argument, NULL, 'V'},
>          {"lb-dst", required_argument, NULL, OPT_LB_DST},
> +        {"select-id", required_argument, NULL, OPT_SELECT_ID},
>          DAEMON_LONG_OPTIONS,
>          VLOG_LONG_OPTIONS,
>          STREAM_SSL_LONG_OPTIONS,
> @@ -302,6 +317,10 @@ parse_options(int argc, char *argv[])
>              parse_lb_option(optarg);
>              break;
>
> +        case OPT_SELECT_ID:
> +            parse_select_option(optarg);
> +            break;
> +
>          case 'h':
>              usage();
>
> @@ -1991,6 +2010,46 @@ execute_ct_lb(const struct ovnact_ct_lb *ct_lb,
>  }
>
>  static void
> +execute_select(const struct ovnact_select *select,
> +              const struct ovntrace_datapath *dp, struct flow *uflow,
> +              enum ovnact_pipeline pipeline, struct ovs_list *super)
> +{
> +    struct flow select_flow = *uflow;
> +
> +    const struct ovnact_select_dst *dst = NULL;
> +    ovs_assert(select->n_dsts > 1);
> +    bool user_specified = false;
> +    for (int i = 0; i < select->n_dsts; i++) {
> +        const struct ovnact_select_dst *d = &select->dsts[i];
> +
> +        /* Check for the dst specified by --select-id, if any. */
> +        if (select_id == d->id) {
> +            dst = d;
> +            user_specified = true;
> +            break;
> +        }
> +    }
> +
> +    if (!dst) {
> +        /* Select a random dst as a fallback. */
> +        dst = &select->dsts[random_range(select->n_dsts)];
> +    }
> +
> +    struct mf_subfield sf = expr_resolve_field(&select->res_field);
> +    union mf_subvalue sv = { .be16_int = htons(dst->id) };
> +    mf_write_subfield_flow(&sf, &sv, &select_flow);
> +    struct ds sf_str = DS_EMPTY_INITIALIZER;
> +    expr_field_format(&select->res_field, &sf_str);
> +    struct ovntrace_node *node = ovntrace_node_append(
> +        super, OVNTRACE_NODE_TRANSFORMATION,
> +        "select: %s = %"PRIu16"%s",
> +        ds_cstr(&sf_str), dst->id, user_specified ?  "" :
> +        " /* Randomly selected. Use --select-id to specify. */");
> +    ds_destroy(&sf_str);
> +    trace__(dp, &select_flow, select->ltable, pipeline, &node->subs);
> +}
> +
> +static void
>  execute_log(const struct ovnact_log *log, struct flow *uflow,
>              struct ovs_list *super)
>  {
> @@ -2100,6 +2159,11 @@ trace_actions(const struct ovnact *ovnacts, size_t ovnacts_len,
>              execute_ct_lb(ovnact_get_CT_LB(a), dp, uflow, pipeline, super);
>              break;
>
> +        case OVNACT_SELECT:
> +            execute_select(ovnact_get_SELECT(a), dp, uflow,
> +                                   pipeline, super);
> +            break;
> +
>          case OVNACT_CT_CLEAR:
>              flow_clear_conntrack(uflow);
>              break;
> --
> 2.1.0
>
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>


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