Looks good, really good idea. Thanks.
Ethan
On Tue, Jul 24, 2012 at 1:06 PM, Ben Pfaff <b...@nicira.com> wrote:
> There are many reasons why OFPP_NORMAL translation can drop packets, and
> it's often far from obvious why. This should make it easier to debug.
>
> Bug #12618.
> Signed-off-by: Ben Pfaff <b...@nicira.com>
> ---
> ofproto/ofproto-dpif.c | 51 +++++++++++++++++++++++++++++++++++++++++++----
> 1 files changed, 46 insertions(+), 5 deletions(-)
>
> diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
> index dc15c15..c25c513 100644
> --- a/ofproto/ofproto-dpif.c
> +++ b/ofproto/ofproto-dpif.c
> @@ -243,6 +243,11 @@ struct action_xlate_ctx {
> * calling action_xlate_ctx_init(). */
> void (*resubmit_hook)(struct action_xlate_ctx *, struct rule_dpif *rule);
>
> + /* If nonnull, flow translation calls this function to report some
> + * significant decision, e.g. to explain why OFPP_NORMAL translation
> + * dropped a packet. */
> + void (*report_hook)(struct action_xlate_ctx *, const char *s);
> +
> /* If nonnull, flow translation credits the specified statistics to each
> * rule reached through a resubmit or OFPP_TABLE action.
> *
> @@ -299,6 +304,8 @@ static void compose_slow_path(const struct ofproto_dpif
> *, const struct flow *,
> const struct nlattr **actionsp,
> size_t *actions_lenp);
>
> +static void xlate_report(struct action_xlate_ctx *ctx, const char *s);
> +
> /* A subfacet (see "struct subfacet" below) has three possible installation
> * states:
> *
> @@ -5570,6 +5577,7 @@ action_xlate_ctx_init(struct action_xlate_ctx *ctx,
> ctx->may_learn = packet != NULL;
> ctx->tcp_flags = tcp_flags;
> ctx->resubmit_hook = NULL;
> + ctx->report_hook = NULL;
> ctx->resubmit_stats = NULL;
> }
>
> @@ -5696,6 +5704,14 @@ xlate_actions_for_side_effects(struct action_xlate_ctx
> *ctx,
> xlate_actions(ctx, ofpacts, ofpacts_len, &odp_actions);
> ofpbuf_uninit(&odp_actions);
> }
> +
> +static void
> +xlate_report(struct action_xlate_ctx *ctx, const char *s)
> +{
> + if (ctx->report_hook) {
> + ctx->report_hook(ctx, s);
> + }
> +}
>
> /* OFPP_NORMAL implementation. */
>
> @@ -6107,14 +6123,17 @@ lookup_input_bundle(const struct ofproto_dpif
> *ofproto, uint16_t in_port,
> * so in one special case.
> */
> static bool
> -is_admissible(struct ofproto_dpif *ofproto, const struct flow *flow,
> - struct ofport_dpif *in_port, uint16_t vlan, tag_type *tags)
> +is_admissible(struct action_xlate_ctx *ctx, struct ofport_dpif *in_port,
> + uint16_t vlan)
> {
> + struct ofproto_dpif *ofproto = ctx->ofproto;
> + struct flow *flow = &ctx->flow;
> struct ofbundle *in_bundle = in_port->bundle;
>
> /* Drop frames for reserved multicast addresses
> * only if forward_bpdu option is absent. */
> if (!ofproto->up.forward_bpdu && eth_addr_is_reserved(flow->dl_dst)) {
> + xlate_report(ctx, "packet has reserved destination MAC, dropping");
> return false;
> }
>
> @@ -6122,11 +6141,12 @@ is_admissible(struct ofproto_dpif *ofproto, const
> struct flow *flow,
> struct mac_entry *mac;
>
> switch (bond_check_admissibility(in_bundle->bond, in_port,
> - flow->dl_dst, tags)) {
> + flow->dl_dst, &ctx->tags)) {
> case BV_ACCEPT:
> break;
>
> case BV_DROP:
> + xlate_report(ctx, "bonding refused admissibility, dropping");
> return false;
>
> case BV_DROP_IF_MOVED:
> @@ -6134,6 +6154,8 @@ is_admissible(struct ofproto_dpif *ofproto, const
> struct flow *flow,
> if (mac && mac->port.p != in_bundle &&
> (!is_gratuitous_arp(flow)
> || mac_entry_is_grat_arp_locked(mac))) {
> + xlate_report(ctx, "SLB bond thinks this packet looped back, "
> + "dropping");
> return false;
> }
> break;
> @@ -6157,6 +6179,7 @@ xlate_normal(struct action_xlate_ctx *ctx)
> in_bundle = lookup_input_bundle(ctx->ofproto, ctx->flow.in_port,
> ctx->packet != NULL, &in_port);
> if (!in_bundle) {
> + xlate_report(ctx, "no input bundle, dropping");
> return;
> }
>
> @@ -6169,6 +6192,7 @@ xlate_normal(struct action_xlate_ctx *ctx)
> "VLAN tag received on port %s",
> ctx->ofproto->up.name, in_bundle->name);
> }
> + xlate_report(ctx, "partial VLAN tag, dropping");
> return;
> }
>
> @@ -6180,19 +6204,20 @@ xlate_normal(struct action_xlate_ctx *ctx)
> "%s, which is reserved exclusively for mirroring",
> ctx->ofproto->up.name, in_bundle->name);
> }
> + xlate_report(ctx, "input port is mirror output port, dropping");
> return;
> }
>
> /* Check VLAN. */
> vid = vlan_tci_to_vid(ctx->flow.vlan_tci);
> if (!input_vid_is_valid(vid, in_bundle, ctx->packet != NULL)) {
> + xlate_report(ctx, "disallowed VLAN VID for this input port,
> dropping");
> return;
> }
> vlan = input_vid_to_vlan(in_bundle, vid);
>
> /* Check other admissibility requirements. */
> - if (in_port &&
> - !is_admissible(ctx->ofproto, &ctx->flow, in_port, vlan,
> &ctx->tags)) {
> + if (in_port && !is_admissible(ctx, in_port, vlan)) {
> return;
> }
>
> @@ -6206,11 +6231,15 @@ xlate_normal(struct action_xlate_ctx *ctx)
> &ctx->tags);
> if (mac) {
> if (mac->port.p != in_bundle) {
> + xlate_report(ctx, "forwarding to learned port");
> output_normal(ctx, mac->port.p, vlan);
> + } else {
> + xlate_report(ctx, "learned port is input port, dropping");
> }
> } else {
> struct ofbundle *bundle;
>
> + xlate_report(ctx, "no learned MAC for destination, flooding");
> HMAP_FOR_EACH (bundle, hmap_node, &ctx->ofproto->bundles) {
> if (bundle != in_bundle
> && ofbundle_includes_vlan(bundle, vlan)
> @@ -6601,6 +6630,17 @@ trace_resubmit(struct action_xlate_ctx *ctx, struct
> rule_dpif *rule)
> }
>
> static void
> +trace_report(struct action_xlate_ctx *ctx, const char *s)
> +{
> + struct trace_ctx *trace = CONTAINER_OF(ctx, struct trace_ctx, ctx);
> + struct ds *result = trace->result;
> +
> + ds_put_char_multiple(result, '\t', ctx->recurse);
> + ds_put_cstr(result, s);
> + ds_put_char(result, '\n');
> +}
> +
> +static void
> ofproto_unixctl_trace(struct unixctl_conn *conn, int argc, const char
> *argv[],
> void *aux OVS_UNUSED)
> {
> @@ -6750,6 +6790,7 @@ ofproto_trace(struct ofproto_dpif *ofproto, const
> struct flow *flow,
> action_xlate_ctx_init(&trace.ctx, ofproto, flow, initial_tci,
> rule, tcp_flags, packet);
> trace.ctx.resubmit_hook = trace_resubmit;
> + trace.ctx.report_hook = trace_report;
> xlate_actions(&trace.ctx, rule->up.ofpacts, rule->up.ofpacts_len,
> &odp_actions);
>
> --
> 1.7.2.5
>
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> dev mailing list
> dev@openvswitch.org
> http://openvswitch.org/mailman/listinfo/dev
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