ipv6, trace: fix tos reporting on fib6_table_lookup

flowi6_tos of struct flowi6 is unused in IPv6, therefore dumping tos on
that tracepoint will also give incorrect information wrt traffic class.

If we want to fix it, we need to extract it via ip6_tclass(flp->flowlabel).
While for the same test case I get a count of 0 non-zero tos values before
the change, they now start to show up after the change:

  # ./perf record -e fib6:fib6_table_lookup -a sleep 10
  # ./perf script | grep -v "tos 0" | wc -l
  60

Since there's no user in the kernel tree anymore of flowi6_tos, remove the
define to avoid any future confusion on this.

Fixes: b811580d91e9 ("net: IPv6 fib lookup tracepoint")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 2 insertions, 2 deletions

diff --git a/include/net/flow.h b/include/net/flow.h
index 83969eebebf3..d47ef4bb5423 100644
--- a/include/net/flow.h
+++ b/include/net/flow.h
@@ -127,7 +127,6 @@ struct flowi6 {
 #define flowi6_oif              __fl_common.flowic_oif
 #define flowi6_iif              __fl_common.flowic_iif
 #define flowi6_mark             __fl_common.flowic_mark
-#define flowi6_tos              __fl_common.flowic_tos
 #define flowi6_scope            __fl_common.flowic_scope
 #define flowi6_proto            __fl_common.flowic_proto
 #define flowi6_flags            __fl_common.flowic_flags
@@ -135,6 +134,7 @@ struct flowi6 {
 #define flowi6_tun_key          __fl_common.flowic_tun_key
         struct in6_addr         daddr;
         struct in6_addr         saddr;
+        /* Note: flowi6_tos is encoded in flowlabel, too. */
         __be32                  flowlabel;
         union flowi_uli         uli;
 #define fl6_sport               uli.ports.sport
diff --git a/include/trace/events/fib6.h b/include/trace/events/fib6.h
index 4cf6bac4686d..d60096cddb2a 100644
--- a/include/trace/events/fib6.h
+++ b/include/trace/events/fib6.h
@@ -37,7 +37,7 @@ TRACE_EVENT(fib6_table_lookup,
                 __entry->tb_id = tb_id;
                 __entry->oif = flp->flowi6_oif;
                 __entry->iif = flp->flowi6_iif;
-                __entry->tos = flp->flowi6_tos;
+                __entry->tos = ip6_tclass(flp->flowlabel);
                 __entry->scope = flp->flowi6_scope;
                 __entry->flags = flp->flowi6_flags;