[ovs-dev] [PATCH 01/10] netlink: Add function to filter nlattrs

[Eric Garver]

Add a utility function to filter out a given type from a list of netlink
attributes. This removes an item from the set.

Signed-off-by: Eric Garver <e at erig.me>
---
 lib/netlink.c | 20 ++++++++++++++++++++
 lib/netlink.h |  1 +
 2 files changed, 21 insertions(+)

diff --git a/lib/netlink.c b/lib/netlink.c
index 4cf1aaca621c..420208a0c51e 100644
--- a/lib/netlink.c
+++ b/lib/netlink.c
@@ -927,3 +927,23 @@ nl_attr_find_nested(const struct nlattr *nla, uint16_t type)
 {
     return nl_attr_find__(nl_attr_get(nla), nl_attr_get_size(nla), type);
 }
+
+/*
+ * Filter nlattr type from set of nlattrs.
+ * This changes the data in place. So caller should make a copy if required.
+ */
+void
+nl_attr_filter(struct nlattr *attrs, size_t *attrs_len, uint16_t type)
+{
+    size_t size = *attrs_len;
+    struct nlattr *nla;
+    size_t left;
+
+    NL_ATTR_FOR_EACH (nla, left, attrs, size) {
+        if (nl_attr_type(nla) == type) {
+            *attrs_len -= nl_attr_len_pad(nla, left);
+            memmove(nla, nl_attr_next(nla), left - nl_attr_len_pad(nla, left));
+            return;
+        }
+    }
+}
diff --git a/lib/netlink.h b/lib/netlink.h
index 6dfac27c9d4b..256246676b4b 100644
--- a/lib/netlink.h
+++ b/lib/netlink.h
@@ -240,5 +240,6 @@ const struct nlattr *nl_attr_find(const struct ofpbuf *, size_t hdr_len,
 const struct nlattr *nl_attr_find_nested(const struct nlattr *, uint16_t type);
 const struct nlattr *nl_attr_find__(const struct nlattr *attrs, size_t size,
                                     uint16_t type);
+void nl_attr_filter(struct nlattr *attrs, size_t *attrs_len, uint16_t type);
 
 #endif /* netlink.h */
-- 
2.12.0