Merge pull request #14433 from muxi/add-cronet-bin-base64

Add binary metadata support for cronet transport

3 files changed, 67 insertions, 22 deletions

diff --git a/src/core/ext/transport/chttp2/transport/bin_decoder.cc b/src/core/ext/transport/chttp2/transport/bin_decoder.cc
index 91980e6974..831a36961e 100644
--- a/src/core/ext/transport/chttp2/transport/bin_decoder.cc
+++ b/src/core/ext/transport/chttp2/transport/bin_decoder.cc
@@ -75,6 +75,32 @@ static bool input_is_valid(uint8_t* input_ptr, size_t length) {
 #define COMPOSE_OUTPUT_BYTE_2(input_ptr) \
   (uint8_t)((decode_table[input_ptr[2]] << 6) | decode_table[input_ptr[3]])
 
+// By RFC 4648, if the length of the encoded string without padding is 4n+r,
+// the length of decoded string is: 1) 3n if r = 0, 2) 3n + 1 if r = 2, 3, or
+// 3) invalid if r = 1.
+size_t grpc_chttp2_base64_infer_length_after_decode(const grpc_slice& slice) {
+  size_t len = GRPC_SLICE_LENGTH(slice);
+  const uint8_t* bytes = GRPC_SLICE_START_PTR(slice);
+  while (len > 0 && bytes[len - 1] == '=') {
+    len--;
+  }
+  if (GRPC_SLICE_LENGTH(slice) - len > 2) {
+    gpr_log(GPR_ERROR,
+            "Base64 decoding failed. Input has more than 2 paddings.");
+    return 0;
+  }
+  size_t tuples = len / 4;
+  size_t tail_case = len % 4;
+  if (tail_case == 1) {
+    gpr_log(GPR_ERROR,
+            "Base64 decoding failed. Input has a length of %zu (without"
+            " padding), which is invalid.\n",
+            len);
+    return 0;
+  }
+  return tuples * 3 + tail_xtra[tail_case];
+}
+
 bool grpc_base64_decode_partial(struct grpc_base64_decode_context* ctx) {
   size_t input_tail;
 
diff --git a/src/core/ext/transport/chttp2/transport/bin_decoder.h b/src/core/ext/transport/chttp2/transport/bin_decoder.h
index 9cb75ccd81..a0d74fb20d 100644
--- a/src/core/ext/transport/chttp2/transport/bin_decoder.h
+++ b/src/core/ext/transport/chttp2/transport/bin_decoder.h
@@ -48,4 +48,7 @@ grpc_slice grpc_chttp2_base64_decode(grpc_slice input);
 grpc_slice grpc_chttp2_base64_decode_with_length(grpc_slice input,
                                                  size_t output_length);
 
+/* Infer the length of decoded data from encoded data. */
+size_t grpc_chttp2_base64_infer_length_after_decode(const grpc_slice& slice);
+
 #endif /* GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_BIN_DECODER_H */
diff --git a/src/core/ext/transport/cronet/transport/cronet_transport.cc b/src/core/ext/transport/cronet/transport/cronet_transport.cc
index 8904c122a7..c367f9c465 100644
--- a/src/core/ext/transport/cronet/transport/cronet_transport.cc
+++ b/src/core/ext/transport/cronet/transport/cronet_transport.cc
@@ -24,6 +24,8 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
+#include "src/core/ext/transport/chttp2/transport/bin_decoder.h"
+#include "src/core/ext/transport/chttp2/transport/bin_encoder.h"
 #include "src/core/ext/transport/chttp2/transport/incoming_metadata.h"
 #include "src/core/ext/transport/cronet/transport/cronet_transport.h"
 #include "src/core/lib/gpr/host_port.h"
@@ -393,6 +395,29 @@ static void execute_from_storage(stream_obj* s) {
   gpr_mu_unlock(&s->mu);
 }
 
+static void convert_cronet_array_to_metadata(
+    const bidirectional_stream_header_array* header_array,
+    grpc_chttp2_incoming_metadata_buffer* mds) {
+  for (size_t i = 0; i < header_array->count; i++) {
+    CRONET_LOG(GPR_DEBUG, "header key=%s, value=%s",
+               header_array->headers[i].key, header_array->headers[i].value);
+    grpc_slice key = grpc_slice_intern(
+        grpc_slice_from_static_string(header_array->headers[i].key));
+    grpc_slice value;
+    if (grpc_is_binary_header(key)) {
+      value = grpc_slice_from_static_string(header_array->headers[i].value);
+      value = grpc_slice_intern(grpc_chttp2_base64_decode_with_length(
+          value, grpc_chttp2_base64_infer_length_after_decode(value)));
+    } else {
+      value = grpc_slice_intern(
+          grpc_slice_from_static_string(header_array->headers[i].value));
+    }
+    GRPC_LOG_IF_ERROR("convert_cronet_array_to_metadata",
+                      grpc_chttp2_incoming_metadata_buffer_add(
+                          mds, grpc_mdelem_from_slices(key, value)));
+  }
+}
+
 /*
   Cronet callback
 */
@@ -517,16 +542,7 @@ static void on_response_headers_received(
          sizeof(s->state.rs.initial_metadata));
   grpc_chttp2_incoming_metadata_buffer_init(&s->state.rs.initial_metadata,
                                             s->arena);
-  for (size_t i = 0; i < headers->count; i++) {
-    GRPC_LOG_IF_ERROR("on_response_headers_received",
-                      grpc_chttp2_incoming_metadata_buffer_add(
-                          &s->state.rs.initial_metadata,
-                          grpc_mdelem_from_slices(
-                              grpc_slice_intern(grpc_slice_from_static_string(
-                                  headers->headers[i].key)),
-                              grpc_slice_intern(grpc_slice_from_static_string(
-                                  headers->headers[i].value)))));
-  }
+  convert_cronet_array_to_metadata(headers, &s->state.rs.initial_metadata);
   s->state.state_callback_received[OP_RECV_INITIAL_METADATA] = true;
   if (!(s->state.state_op_done[OP_CANCEL_ERROR] ||
         s->state.state_callback_received[OP_FAILED])) {
@@ -621,18 +637,11 @@ static void on_response_trailers_received(
   s->state.rs.trailing_metadata_valid = false;
   grpc_chttp2_incoming_metadata_buffer_init(&s->state.rs.trailing_metadata,
                                             s->arena);
-  for (size_t i = 0; i < trailers->count; i++) {
-    CRONET_LOG(GPR_DEBUG, "trailer key=%s, value=%s", trailers->headers[i].key,
-               trailers->headers[i].value);
-    GRPC_LOG_IF_ERROR("on_response_trailers_received",
-                      grpc_chttp2_incoming_metadata_buffer_add(
-                          &s->state.rs.trailing_metadata,
-                          grpc_mdelem_from_slices(
-                              grpc_slice_intern(grpc_slice_from_static_string(
-                                  trailers->headers[i].key)),
-                              grpc_slice_intern(grpc_slice_from_static_string(
-                                  trailers->headers[i].value)))));
+  convert_cronet_array_to_metadata(trailers, &s->state.rs.trailing_metadata);
+  if (trailers->count > 0) {
     s->state.rs.trailing_metadata_valid = true;
+  }
+  for (size_t i = 0; i < trailers->count; i++) {
     if (0 == strcmp(trailers->headers[i].key, "grpc-status") &&
         0 != strcmp(trailers->headers[i].value, "0")) {
       s->state.fail_state = true;
@@ -721,7 +730,14 @@ static void convert_metadata_to_cronet_headers(
     grpc_mdelem mdelem = curr->md;
     curr = curr->next;
     char* key = grpc_slice_to_c_string(GRPC_MDKEY(mdelem));
-    char* value = grpc_slice_to_c_string(GRPC_MDVALUE(mdelem));
+    char* value;
+    if (grpc_is_binary_header(GRPC_MDKEY(mdelem))) {
+      grpc_slice wire_value = grpc_chttp2_base64_encode(GRPC_MDVALUE(mdelem));
+      value = grpc_slice_to_c_string(wire_value);
+      grpc_slice_unref(wire_value);
+    } else {
+      value = grpc_slice_to_c_string(GRPC_MDVALUE(mdelem));
+    }
     if (grpc_slice_eq(GRPC_MDKEY(mdelem), GRPC_MDSTR_SCHEME) ||
         grpc_slice_eq(GRPC_MDKEY(mdelem), GRPC_MDSTR_AUTHORITY)) {
       /* Cronet populates these fields on its own */