4 files changed, 41 insertions, 10 deletions

diff --git a/src/core/transport/chttp2/stream_encoder.c b/src/core/transport/chttp2/stream_encoder.c
index d30059abf8..3dfea3ca4b 100644
--- a/src/core/transport/chttp2/stream_encoder.c
+++ b/src/core/transport/chttp2/stream_encoder.c
@@ -441,7 +441,7 @@ static void deadline_enc(grpc_chttp2_hpack_compressor *c, gpr_timespec deadline,
       gpr_time_sub(deadline, gpr_now(GPR_CLOCK_REALTIME)), timeout_str);
   mdelem = grpc_mdelem_from_metadata_strings(
       c->mdctx, GRPC_MDSTR_REF(c->timeout_key_str),
-      grpc_mdstr_from_string(c->mdctx, timeout_str));
+      grpc_mdstr_from_string(c->mdctx, timeout_str, 0));
   mdelem = hpack_enc(c, mdelem, st);
   if (mdelem) GRPC_MDELEM_UNREF(mdelem);
 }
@@ -456,7 +456,7 @@ void grpc_chttp2_hpack_compressor_init(grpc_chttp2_hpack_compressor *c,
                                        grpc_mdctx *ctx) {
   memset(c, 0, sizeof(*c));
   c->mdctx = ctx;
-  c->timeout_key_str = grpc_mdstr_from_string(ctx, "grpc-timeout");
+  c->timeout_key_str = grpc_mdstr_from_string(ctx, "grpc-timeout", 0);
 }
 
 void grpc_chttp2_hpack_compressor_destroy(grpc_chttp2_hpack_compressor *c) {
diff --git a/src/core/transport/chttp2_transport.c b/src/core/transport/chttp2_transport.c
index c923d5e42f..634bedd625 100644
--- a/src/core/transport/chttp2_transport.c
+++ b/src/core/transport/chttp2_transport.c
@@ -228,7 +228,7 @@ static void init_transport(grpc_chttp2_transport *t,
   t->global.pings.next = t->global.pings.prev = &t->global.pings;
   t->parsing.is_client = is_client;
   t->parsing.str_grpc_timeout =
-      grpc_mdstr_from_string(t->metadata_context, "grpc-timeout");
+      grpc_mdstr_from_string(t->metadata_context, "grpc-timeout", 0);
   t->parsing.deframe_state =
       is_client ? GRPC_DTS_FH_0 : GRPC_DTS_CLIENT_PREFIX_0;
   t->writing.is_client = is_client;
diff --git a/src/core/transport/metadata.c b/src/core/transport/metadata.c
index e95b7a21f9..c5012baa24 100644
--- a/src/core/transport/metadata.c
+++ b/src/core/transport/metadata.c
@@ -309,7 +309,36 @@ static void slice_unref(void *p) {
   unlock(ctx);
 }
 
-grpc_mdstr *grpc_mdstr_from_string(grpc_mdctx *ctx, const char *str) {
+grpc_mdstr *grpc_mdstr_from_string(grpc_mdctx *ctx, const char *str, int canonicalize_key) {
+  if (canonicalize_key) {
+    size_t len;
+    size_t i;
+    int canonical = 1;
+
+    for (i = 0; str[i]; i++) {
+      if (str[i] >= 'A' && str[i] <= 'Z') {
+        canonical = 0;
+      }
+    }
+    len = i;
+
+    if (canonical) {
+      return grpc_mdstr_from_buffer(ctx, (const gpr_uint8 *)str, len);
+    } else {
+      char *copy = gpr_malloc(len + 1);
+      grpc_mdstr *ret;
+      for (i = 0; i < len; i++) {
+        if (str[i] >= 'A' && str[i] <= 'Z') {
+          copy[i] = str[i] - 'A' + 'a';
+        } else {
+          copy[i] = str[i];
+        }
+      }
+      ret = grpc_mdstr_from_buffer(ctx, (const gpr_uint8 *)copy, len);
+      gpr_free(copy);
+      return ret;
+    }
+  }
   return grpc_mdstr_from_buffer(ctx, (const gpr_uint8 *)str, strlen(str));
 }
 
@@ -491,8 +520,8 @@ grpc_mdelem *grpc_mdelem_from_metadata_strings(grpc_mdctx *ctx,
 grpc_mdelem *grpc_mdelem_from_strings(grpc_mdctx *ctx, const char *key,
                                       const char *value) {
   return grpc_mdelem_from_metadata_strings(ctx,
-                                           grpc_mdstr_from_string(ctx, key),
-                                           grpc_mdstr_from_string(ctx, value));
+                                           grpc_mdstr_from_string(ctx, key, 0),
+                                           grpc_mdstr_from_string(ctx, value, 0));
 }
 
 grpc_mdelem *grpc_mdelem_from_slices(grpc_mdctx *ctx, gpr_slice key,
@@ -504,9 +533,10 @@ grpc_mdelem *grpc_mdelem_from_slices(grpc_mdctx *ctx, gpr_slice key,
 grpc_mdelem *grpc_mdelem_from_string_and_buffer(grpc_mdctx *ctx,
                                                 const char *key,
                                                 const gpr_uint8 *value,
-                                                size_t value_length) {
+                                                size_t value_length,
+                                                int canonicalize_key) {
   return grpc_mdelem_from_metadata_strings(
-      ctx, grpc_mdstr_from_string(ctx, key),
+      ctx, grpc_mdstr_from_string(ctx, key, canonicalize_key),
       grpc_mdstr_from_buffer(ctx, value, value_length));
 }
 
diff --git a/src/core/transport/metadata.h b/src/core/transport/metadata.h
index 99b15322c3..15ef9bb555 100644
--- a/src/core/transport/metadata.h
+++ b/src/core/transport/metadata.h
@@ -95,7 +95,7 @@ size_t grpc_mdctx_get_mdtab_free_test_only(grpc_mdctx *mdctx);
 
 /* Constructors for grpc_mdstr instances; take a variety of data types that
    clients may have handy */
-grpc_mdstr *grpc_mdstr_from_string(grpc_mdctx *ctx, const char *str);
+grpc_mdstr *grpc_mdstr_from_string(grpc_mdctx *ctx, const char *str, int perform_key_canonicalization);
 /* Unrefs the slice. */
 grpc_mdstr *grpc_mdstr_from_slice(grpc_mdctx *ctx, gpr_slice slice);
 grpc_mdstr *grpc_mdstr_from_buffer(grpc_mdctx *ctx, const gpr_uint8 *str,
@@ -117,7 +117,8 @@ grpc_mdelem *grpc_mdelem_from_slices(grpc_mdctx *ctx, gpr_slice key,
 grpc_mdelem *grpc_mdelem_from_string_and_buffer(grpc_mdctx *ctx,
                                                 const char *key,
                                                 const gpr_uint8 *value,
-                                                size_t value_length);
+                                                size_t value_length,
+                                                int canonicalize_key);
 
 /* Mutator and accessor for grpc_mdelem user data. The destructor function
    is used as a type tag and is checked during user_data fetch. */