Re: [RFC] Inverse of flowi{4,6}_oif: flowi{4,6}_not_oif

[Jason A. Donenfeld]

FYI, for v4 at least, it's ridiculously easy and simple to implement:

=~=~=~=~=~=~=~=~=

diff --git a/include/net/flow.h b/include/net/flow.h
index 83969ee..29967ad 100644
--- a/include/net/flow.h
+++ b/include/net/flow.h
@@ -26,6 +26,7 @@ struct flowi_tunnel {

 struct flowi_common {
  int flowic_oif;
+ int flowic_not_oif;
  int flowic_iif;
  __u32 flowic_mark;
  __u8 flowic_tos;
@@ -67,6 +68,7 @@ union flowi_uli {
 struct flowi4 {
  struct flowi_common __fl_common;
 #define flowi4_oif  __fl_common.flowic_oif
+#define flowi4_not_oif  __fl_common.flowic_not_oif
 #define flowi4_iif  __fl_common.flowic_iif
 #define flowi4_mark  __fl_common.flowic_mark
 #define flowi4_tos  __fl_common.flowic_tos
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 7aea0cc..d03e991 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1429,6 +1429,8 @@ found:
         flp->flowi4_oif != nh->nh_oif)
      continue;
    }
+   if (flp->flowi4_not_oif && flp->flowi4_not_oif == nh->nh_oif)
+    continue;

    if (!(fib_flags & FIB_LOOKUP_NOREF))
     atomic_inc(&fi->fib_clntref);