[PATCH/RFC repost 2/8] netlink: Allow suppression of warnings for duplicate attributes

[Simon Horman <simon.horman@netronome.com>]

Add a multiple field to struct nl_policy which if set suppresses
warning of duplicate attributes in nl_parse_nested().

As is the case without this patch only the last occurrence of an
attribute is stored in attrs by nl_parse_nested(). As such
if the multiple field of struct nl_policy is set then it
is up to the caller to parse the message to extract all the attributes.

This is in preparation for allowing multiple OVS_SELECT_GROUP_ATTR_BUCKET
attributes in a nested OVS_ACTION_ATTR_SELECT_GROUP attribute.

Signed-off-by: Simon Horman <simon.horman@netronome.com>
---
 lib/netlink.c | 2 +-
 lib/netlink.h | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/netlink.c b/lib/netlink.c
index 24b2168..bc30248 100644
--- a/lib/netlink.c
+++ b/lib/netlink.c
@@ -743,7 +743,7 @@ nl_policy_parse(const struct ofpbuf *msg, size_t nla_offset,
             if (!nl_attr_validate(nla, e)) {
                 return false;
             }
-            if (attrs[type]) {
+            if (attrs[type] && !e->multiple) {
                 VLOG_DBG_RL(&rl, "duplicate attr %"PRIu16, type);
             }
             attrs[type] = nla;
diff --git a/lib/netlink.h b/lib/netlink.h
index f9234da..b0a72fd 100644
--- a/lib/netlink.h
+++ b/lib/netlink.h
@@ -195,6 +195,7 @@ struct nl_policy
     enum nl_attr_type type;
     size_t min_len, max_len;
     bool optional;
+    bool multiple;
 };
 
 #define NL_POLICY_FOR(TYPE) \
-- 
2.0.1