[ovs-dev] [PATCH 39/41] nx-match: Add functions for raw decoding and encoding of OXM.

[Ben Pfaff]

The existing functions either assumed that we were working with NXM
(instead of OXM), or they added or parsed a header before OXM headers.
These aren't needed when OXM is encapsulated inside a property, as will be
the case in an upcoming commit.

Signed-off-by: Ben Pfaff <blp at ovn.org>
---
 lib/nx-match.c | 30 ++++++++++++++++++++++++++++--
 lib/nx-match.h |  7 ++++++-
 2 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/lib/nx-match.c b/lib/nx-match.c
index 11bcd95..0f695f0 100644
--- a/lib/nx-match.c
+++ b/lib/nx-match.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2011, 2012, 2013, 2014, 2015 Nicira, Inc.
+ * Copyright (c) 2010, 2011, 2012, 2013, 2014, 2015, 2016 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -630,6 +630,18 @@ oxm_pull_match_loose(struct ofpbuf *b, struct match *match)
     return oxm_pull_match__(b, false, match);
 }
 
+/* Parses the OXM match description in the 'oxm_len' bytes in 'oxm'.  Stores
+ * the result in 'match'.
+ *
+ * Fails with an error when encountering unknown OXM headers.
+ *
+ * Returns 0 if successful, otherwise an OpenFlow error code. */
+enum ofperr
+oxm_decode_match(const void *oxm, size_t oxm_len, struct match *match)
+{
+    return nx_pull_raw(oxm, oxm_len, true, match, NULL, NULL);
+}
+
 /* Verify an array of OXM TLVs treating value of each TLV as a mask,
  * disallowing masks in each TLV and ignoring pre-requisites. */
 enum ofperr
@@ -1099,7 +1111,7 @@ nx_put_match(struct ofpbuf *b, const struct match *match,
 }
 
 /* Appends to 'b' an struct ofp11_match_header followed by the OXM format that
- * expresses 'cr', plus enough zero bytes to pad the data appended out to a
+ * expresses 'match', plus enough zero bytes to pad the data appended out to a
  * multiple of 8.
  *
  * OXM differs slightly among versions of OpenFlow.  Specify the OpenFlow
@@ -1130,6 +1142,20 @@ oxm_put_match(struct ofpbuf *b, const struct match *match,
     return match_len;
 }
 
+/* Appends to 'b' the OXM formats that expresses 'match', without header or
+ * padding.
+ *
+ * OXM differs slightly among versions of OpenFlow.  Specify the OpenFlow
+ * version in use as 'version'.
+ *
+ * This function can cause 'b''s data to be reallocated. */
+void
+oxm_put_raw(struct ofpbuf *b, const struct match *match,
+            enum ofp_version version)
+{
+    nx_put_raw(b, version, match, 0, 0);
+}
+
 /* Appends to 'b' the nx_match format that expresses the tlv corresponding
  * to 'id'. If mask is not all-ones then it is also formated as the value
  * of the tlv. */
diff --git a/lib/nx-match.h b/lib/nx-match.h
index 2625c63..c663e54 100644
--- a/lib/nx-match.h
+++ b/lib/nx-match.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2011, 2012, 2013, 2014 Nicira, Inc.
+ * Copyright (c) 2010, 2011, 2012, 2013, 2014, 2016 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -47,6 +47,7 @@ char *mf_parse_subfield__(struct mf_subfield *sf, const char **s)
 char *mf_parse_subfield(struct mf_subfield *, const char *s)
     OVS_WARN_UNUSED_RESULT;
 
+/* Decoding matches. */
 enum ofperr nx_pull_match(struct ofpbuf *, unsigned int match_len,
                           struct match *,
                           ovs_be64 *cookie, ovs_be64 *cookie_mask);
@@ -55,11 +56,15 @@ enum ofperr nx_pull_match_loose(struct ofpbuf *, unsigned int match_len,
                                 ovs_be64 *cookie_mask);
 enum ofperr oxm_pull_match(struct ofpbuf *, struct match *);
 enum ofperr oxm_pull_match_loose(struct ofpbuf *, struct match *);
+enum ofperr oxm_decode_match(const void *, size_t, struct match *);
 enum ofperr oxm_pull_field_array(const void *, size_t fields_len,
                                  struct field_array *);
+
+/* Encoding matches. */
 int nx_put_match(struct ofpbuf *, const struct match *,
                  ovs_be64 cookie, ovs_be64 cookie_mask);
 int oxm_put_match(struct ofpbuf *, const struct match *, enum ofp_version);
+void oxm_put_raw(struct ofpbuf *, const struct match *, enum ofp_version);
 void oxm_format_field_array(struct ds *, const struct field_array *);
 int oxm_put_field_array(struct ofpbuf *, const struct field_array *,
                         enum ofp_version version);
-- 
2.1.3