librpc: Always call ndr_push_compression_state_init() for compression

This allows the push routine to cache the chosen compression algorithm in
the struct ndr_compression_state in ndr->cstate and so, in claims, avoid
calling ndr_size_CLAIMS_SET_NDR() three times per compression (more in the
overall push).

As claims is now the primary use of the libndr compression code, this is
a reasonable tradeoff compared to the other callers who have more static
algorithm selections.

By removing the struct ndr_compression_state **state argument from
ndr_push_compression_state_init() we make clear that the ndr->cstate
belongs to this NDR context, and this context alone.

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Joseph Sutton <josephsutton@catalyst.net.nz>

4 files changed, 50 insertions, 33 deletions

diff --git a/librpc/ndr/ndr_cab.c b/librpc/ndr/ndr_cab.c
index 322412fdac3..3efb14fc874 100644
--- a/librpc/ndr/ndr_cab.c
+++ b/librpc/ndr/ndr_cab.c
@@ -132,7 +132,7 @@ static enum ndr_err_code ndr_push_folder_cfdata(struct ndr_push *ndr,
 
 	if (cab_ctype == CF_COMPRESS_MSZIP) {
 		ndr_ctype = NDR_COMPRESSION_MSZIP_CAB;
-		NDR_CHECK(ndr_push_compression_state_init(ndr, ndr_ctype, &ndr->cstate));
+		NDR_CHECK(ndr_push_compression_state_init(ndr, ndr_ctype));
 	}
 
 	for (i = 0; i < num_cfdata; i++, r++) {
@@ -189,11 +189,18 @@ static enum ndr_err_code ndr_push_folder_cfdata(struct ndr_push *ndr,
 
 			/* compress via subcontext */
 			NDR_CHECK(ndr_push_subcontext_start(ndr, &push_sub, 0, -1));
+
+			/*
+			 * This assignment replaces a call to
+			 * ndr_push_compression_state_init(push_sub, ndr_ctype))
+			 * here.  This is instead done outside the loop.
+			 */
 			push_sub->cstate = ndr->cstate;
-			NDR_CHECK(ndr_push_compression_start(push_sub, &push_compress, ndr_ctype));
+
+			NDR_CHECK(ndr_push_compression_start(push_sub, &push_compress));
 			ndr_set_flags(&push_compress->flags, LIBNDR_FLAG_REMAINING);
 			NDR_CHECK(ndr_push_DATA_BLOB(push_compress, NDR_SCALARS, r->ab));
-			NDR_CHECK(ndr_push_compression_end(push_sub, push_compress, ndr_ctype));
+			NDR_CHECK(ndr_push_compression_end(push_sub, push_compress));
 			NDR_CHECK(ndr_push_subcontext_end(ndr, push_sub, 0, -1));
 			compressed_length = push_sub->offset;
 
diff --git a/librpc/ndr/ndr_compression.c b/librpc/ndr/ndr_compression.c
index 54f91f9efbf..4c961f84f4e 100644
--- a/librpc/ndr/ndr_compression.c
+++ b/librpc/ndr/ndr_compression.c
@@ -898,10 +898,10 @@ enum ndr_err_code ndr_pull_compression_end(struct ndr_pull *subndr,
   push a compressed subcontext
 */
 enum ndr_err_code ndr_push_compression_start(struct ndr_push *subndr,
-				    struct ndr_push **_uncomndr,
-				    enum ndr_compression_alg compression_alg)
+				    struct ndr_push **_uncomndr)
 {
 	struct ndr_push *uncomndr;
+	enum ndr_compression_alg compression_alg = subndr->cstate->type;
 
 	switch (compression_alg) {
 	case NDR_COMPRESSION_NONE:
@@ -928,13 +928,14 @@ enum ndr_err_code ndr_push_compression_start(struct ndr_push *subndr,
   push a compressed subcontext
 */
 enum ndr_err_code ndr_push_compression_end(struct ndr_push *subndr,
-				  struct ndr_push *uncomndr,
-				  enum ndr_compression_alg compression_alg)
+				  struct ndr_push *uncomndr)
 {
 	struct ndr_pull *ndrpull;
 	bool last = false;
 	z_stream z;
 
+	enum ndr_compression_alg compression_alg = subndr->cstate->type;
+
 	ndrpull = talloc_zero(uncomndr, struct ndr_pull);
 	NDR_ERR_HAVE_NO_MEMORY(ndrpull);
 	ndrpull->flags		= uncomndr->flags;
@@ -1034,12 +1035,17 @@ enum ndr_err_code ndr_pull_compression_state_init(struct ndr_pull *ndr,
 }
 
 enum ndr_err_code ndr_push_compression_state_init(struct ndr_push *ndr,
-						  enum ndr_compression_alg compression_alg,
-						  struct ndr_compression_state **state)
+						  enum ndr_compression_alg compression_alg)
 {
 	struct ndr_compression_state *s;
 	int z_ret;
 
+	/*
+	 * Avoid confusion, NULL out ndr->cstate at the start of the
+	 * compression block
+	 */
+	ndr->cstate = NULL;
+
 	s = talloc_zero(ndr, struct ndr_compression_state);
 	NDR_ERR_HAVE_NO_MEMORY(s);
 	s->type = compression_alg;
@@ -1079,8 +1085,7 @@ enum ndr_err_code ndr_push_compression_state_init(struct ndr_push *ndr,
 		break;
 	}
 
-
-	*state = s;
+	ndr->cstate = s;
 
 	return NDR_ERR_SUCCESS;
 }
diff --git a/librpc/ndr/ndr_compression.h b/librpc/ndr/ndr_compression.h
index 7f938523ada..3d335b2befd 100644
--- a/librpc/ndr/ndr_compression.h
+++ b/librpc/ndr/ndr_compression.h
@@ -42,19 +42,16 @@ enum ndr_err_code ndr_pull_compression_end(struct ndr_pull *subndr,
 				  enum ndr_compression_alg compression_alg,
 				  ssize_t decompressed_len);
 enum ndr_err_code ndr_push_compression_start(struct ndr_push *subndr,
-				    struct ndr_push **_uncomndr,
-				    enum ndr_compression_alg compression_alg);
+				    struct ndr_push **_uncomndr);
 enum ndr_err_code ndr_push_compression_end(struct ndr_push *subndr,
-				  struct ndr_push *uncomndr,
-				  enum ndr_compression_alg compression_alg);
+				  struct ndr_push *uncomndr);
 
 enum ndr_err_code ndr_pull_compression_state_init(struct ndr_pull *ndr,
 						  enum ndr_compression_alg compression_alg,
 						  struct ndr_compression_state **state);
 void ndr_pull_compression_state_free(struct ndr_compression_state *state);
 enum ndr_err_code ndr_push_compression_state_init(struct ndr_push *ndr,
-						  enum ndr_compression_alg compression_alg,
-						  struct ndr_compression_state **state);
+						  enum ndr_compression_alg compression_alg);
 
 #undef _PRINTF_ATTRIBUTE
 #define _PRINTF_ATTRIBUTE(a1, a2)
diff --git a/librpc/ndr/ndr_drsuapi.c b/librpc/ndr/ndr_drsuapi.c
index 0732ee3c6f4..c07ba48ff4b 100644
--- a/librpc/ndr/ndr_drsuapi.c
+++ b/librpc/ndr/ndr_drsuapi.c
@@ -216,10 +216,11 @@ enum ndr_err_code ndr_push_drsuapi_DsGetNCChangesMSZIPCtr1(struct ndr_push *ndr,
 				NDR_CHECK(ndr_push_subcontext_start(ndr, &_ndr_ts, 4, -1));
 				{
 					struct ndr_push *_ndr_ts_compressed;
-					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed, NDR_COMPRESSION_MSZIP));
+					NDR_CHECK(ndr_push_compression_state_init(_ndr_ts, NDR_COMPRESSION_MSZIP));
+					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed));
 					NDR_CHECK(ndr_push_drsuapi_DsGetNCChangesCtr1TS(_ndr_ts_compressed, NDR_SCALARS|NDR_BUFFERS, r->ts));
 					decompressed_length = _ndr_ts_compressed->offset;
-					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed, NDR_COMPRESSION_MSZIP));
+					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed));
 				}
 				compressed_length = _ndr_ts->offset;
 				talloc_free(_ndr_ts);
@@ -237,9 +238,10 @@ enum ndr_err_code ndr_push_drsuapi_DsGetNCChangesMSZIPCtr1(struct ndr_push *ndr,
 				NDR_CHECK(ndr_push_subcontext_start(ndr, &_ndr_ts, 4, -1));
 				{
 					struct ndr_push *_ndr_ts_compressed;
-					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed, NDR_COMPRESSION_MSZIP));
+					NDR_CHECK(ndr_push_compression_state_init(_ndr_ts, NDR_COMPRESSION_MSZIP));
+					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed));
 					NDR_CHECK(ndr_push_drsuapi_DsGetNCChangesCtr1TS(_ndr_ts_compressed, NDR_SCALARS|NDR_BUFFERS, r->ts));
-					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed, NDR_COMPRESSION_MSZIP));
+					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed));
 				}
 				NDR_CHECK(ndr_push_subcontext_end(ndr, _ndr_ts, 4, -1));
 			}
@@ -259,10 +261,11 @@ enum ndr_err_code ndr_push_drsuapi_DsGetNCChangesMSZIPCtr6(struct ndr_push *ndr,
 				NDR_CHECK(ndr_push_subcontext_start(ndr, &_ndr_ts, 4, -1));
 				{
 					struct ndr_push *_ndr_ts_compressed;
-					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed, NDR_COMPRESSION_MSZIP));
+					NDR_CHECK(ndr_push_compression_state_init(_ndr_ts, NDR_COMPRESSION_MSZIP));
+					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed));
 					NDR_CHECK(ndr_push_drsuapi_DsGetNCChangesCtr6TS(_ndr_ts_compressed, NDR_SCALARS|NDR_BUFFERS, r->ts));
 					decompressed_length = _ndr_ts_compressed->offset;
-					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed, NDR_COMPRESSION_MSZIP));
+					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed));
 				}
 				compressed_length = _ndr_ts->offset;
 				talloc_free(_ndr_ts);
@@ -280,9 +283,10 @@ enum ndr_err_code ndr_push_drsuapi_DsGetNCChangesMSZIPCtr6(struct ndr_push *ndr,
 				NDR_CHECK(ndr_push_subcontext_start(ndr, &_ndr_ts, 4, -1));
 				{
 					struct ndr_push *_ndr_ts_compressed;
-					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed, NDR_COMPRESSION_MSZIP));
+					NDR_CHECK(ndr_push_compression_state_init(_ndr_ts, NDR_COMPRESSION_MSZIP));
+					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed));
 					NDR_CHECK(ndr_push_drsuapi_DsGetNCChangesCtr6TS(_ndr_ts_compressed, NDR_SCALARS|NDR_BUFFERS, r->ts));
-					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed, NDR_COMPRESSION_MSZIP));
+					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed));
 				}
 				NDR_CHECK(ndr_push_subcontext_end(ndr, _ndr_ts, 4, -1));
 			}
@@ -302,10 +306,11 @@ enum ndr_err_code ndr_push_drsuapi_DsGetNCChangesWIN2K3_LZ77_DIRECT2Ctr1(struct
 				NDR_CHECK(ndr_push_subcontext_start(ndr, &_ndr_ts, 4, -1));
 				{
 					struct ndr_push *_ndr_ts_compressed;
-					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed, NDR_COMPRESSION_WIN2K3_LZ77_DIRECT2));
+					NDR_CHECK(ndr_push_compression_state_init(_ndr_ts, NDR_COMPRESSION_WIN2K3_LZ77_DIRECT2));
+					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed));
 					NDR_CHECK(ndr_push_drsuapi_DsGetNCChangesCtr1TS(_ndr_ts_compressed, NDR_SCALARS|NDR_BUFFERS, r->ts));
 					decompressed_length = _ndr_ts_compressed->offset;
-					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed, NDR_COMPRESSION_WIN2K3_LZ77_DIRECT2));
+					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed));
 				}
 				compressed_length = _ndr_ts->offset;
 				talloc_free(_ndr_ts);
@@ -323,9 +328,10 @@ enum ndr_err_code ndr_push_drsuapi_DsGetNCChangesWIN2K3_LZ77_DIRECT2Ctr1(struct
 				NDR_CHECK(ndr_push_subcontext_start(ndr, &_ndr_ts, 4, -1));
 				{
 					struct ndr_push *_ndr_ts_compressed;
-					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed, NDR_COMPRESSION_WIN2K3_LZ77_DIRECT2));
+					NDR_CHECK(ndr_push_compression_state_init(_ndr_ts, NDR_COMPRESSION_WIN2K3_LZ77_DIRECT2));
+					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed));
 					NDR_CHECK(ndr_push_drsuapi_DsGetNCChangesCtr1TS(_ndr_ts_compressed, NDR_SCALARS|NDR_BUFFERS, r->ts));
-					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed, NDR_COMPRESSION_WIN2K3_LZ77_DIRECT2));
+					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed));
 				}
 				NDR_CHECK(ndr_push_subcontext_end(ndr, _ndr_ts, 4, -1));
 			}
@@ -345,10 +351,11 @@ enum ndr_err_code ndr_push_drsuapi_DsGetNCChangesWIN2K3_LZ77_DIRECT2Ctr6(struct
 				NDR_CHECK(ndr_push_subcontext_start(ndr, &_ndr_ts, 4, -1));
 				{
 					struct ndr_push *_ndr_ts_compressed;
-					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed, NDR_COMPRESSION_WIN2K3_LZ77_DIRECT2));
+					NDR_CHECK(ndr_push_compression_state_init(_ndr_ts, NDR_COMPRESSION_WIN2K3_LZ77_DIRECT2));
+					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed));
 					NDR_CHECK(ndr_push_drsuapi_DsGetNCChangesCtr6TS(_ndr_ts_compressed, NDR_SCALARS|NDR_BUFFERS, r->ts));
 					decompressed_length = _ndr_ts_compressed->offset;
-					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed, NDR_COMPRESSION_WIN2K3_LZ77_DIRECT2));
+					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed));
 				}
 				compressed_length = _ndr_ts->offset;
 				talloc_free(_ndr_ts);
@@ -366,9 +373,10 @@ enum ndr_err_code ndr_push_drsuapi_DsGetNCChangesWIN2K3_LZ77_DIRECT2Ctr6(struct
 				NDR_CHECK(ndr_push_subcontext_start(ndr, &_ndr_ts, 4, -1));
 				{
 					struct ndr_push *_ndr_ts_compressed;
-					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed, NDR_COMPRESSION_WIN2K3_LZ77_DIRECT2));
+					NDR_CHECK(ndr_push_compression_state_init(_ndr_ts, NDR_COMPRESSION_WIN2K3_LZ77_DIRECT2));
+					NDR_CHECK(ndr_push_compression_start(_ndr_ts, &_ndr_ts_compressed));
 					NDR_CHECK(ndr_push_drsuapi_DsGetNCChangesCtr6TS(_ndr_ts_compressed, NDR_SCALARS|NDR_BUFFERS, r->ts));
-					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed, NDR_COMPRESSION_WIN2K3_LZ77_DIRECT2));
+					NDR_CHECK(ndr_push_compression_end(_ndr_ts, _ndr_ts_compressed));
 				}
 				NDR_CHECK(ndr_push_subcontext_end(ndr, _ndr_ts, 4, -1));
 			}