1 files changed, 440 insertions, 0 deletions

diff --git a/src/core/ext/filters/http/server/http_server_filter.cc b/src/core/ext/filters/http/server/http_server_filter.cc
new file mode 100644
index 0000000000..03958136b4
--- /dev/null
+++ b/src/core/ext/filters/http/server/http_server_filter.cc
@@ -0,0 +1,440 @@
+/*
+ *
+ * Copyright 2015 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include "src/core/ext/filters/http/server/http_server_filter.h"
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <string.h>
+#include "src/core/lib/profiling/timers.h"
+#include "src/core/lib/slice/b64.h"
+#include "src/core/lib/slice/percent_encoding.h"
+#include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/slice/slice_string_helpers.h"
+#include "src/core/lib/transport/static_metadata.h"
+
+#define EXPECTED_CONTENT_TYPE "application/grpc"
+#define EXPECTED_CONTENT_TYPE_LENGTH sizeof(EXPECTED_CONTENT_TYPE) - 1
+
+typedef struct call_data {
+  grpc_call_combiner *call_combiner;
+
+  grpc_linked_mdelem status;
+  grpc_linked_mdelem content_type;
+
+  /* did this request come with path query containing request payload */
+  bool seen_path_with_query;
+  /* flag to ensure payload_bin is delivered only once */
+  bool payload_bin_delivered;
+
+  grpc_metadata_batch *recv_initial_metadata;
+  uint32_t *recv_initial_metadata_flags;
+  /** Closure to call when finished with the hs_on_recv hook */
+  grpc_closure *on_done_recv;
+  /** Closure to call when we retrieve read message from the path URI
+   */
+  grpc_closure *recv_message_ready;
+  grpc_closure *on_complete;
+  grpc_byte_stream **pp_recv_message;
+  grpc_slice_buffer read_slice_buffer;
+  grpc_slice_buffer_stream read_stream;
+
+  /** Receive closures are chained: we inject this closure as the on_done_recv
+      up-call on transport_op, and remember to call our on_done_recv member
+      after handling it. */
+  grpc_closure hs_on_recv;
+  grpc_closure hs_on_complete;
+  grpc_closure hs_recv_message_ready;
+} call_data;
+
+typedef struct channel_data { uint8_t unused; } channel_data;
+
+static grpc_error *server_filter_outgoing_metadata(grpc_exec_ctx *exec_ctx,
+                                                   grpc_call_element *elem,
+                                                   grpc_metadata_batch *b) {
+  if (b->idx.named.grpc_message != NULL) {
+    grpc_slice pct_encoded_msg = grpc_percent_encode_slice(
+        GRPC_MDVALUE(b->idx.named.grpc_message->md),
+        grpc_compatible_percent_encoding_unreserved_bytes);
+    if (grpc_slice_is_equivalent(pct_encoded_msg,
+                                 GRPC_MDVALUE(b->idx.named.grpc_message->md))) {
+      grpc_slice_unref_internal(exec_ctx, pct_encoded_msg);
+    } else {
+      grpc_metadata_batch_set_value(exec_ctx, b->idx.named.grpc_message,
+                                    pct_encoded_msg);
+    }
+  }
+  return GRPC_ERROR_NONE;
+}
+
+static void add_error(const char *error_name, grpc_error **cumulative,
+                      grpc_error *new_err) {
+  if (new_err == GRPC_ERROR_NONE) return;
+  if (*cumulative == GRPC_ERROR_NONE) {
+    *cumulative = GRPC_ERROR_CREATE_FROM_COPIED_STRING(error_name);
+  }
+  *cumulative = grpc_error_add_child(*cumulative, new_err);
+}
+
+static grpc_error *server_filter_incoming_metadata(grpc_exec_ctx *exec_ctx,
+                                                   grpc_call_element *elem,
+                                                   grpc_metadata_batch *b) {
+  call_data *calld = (call_data *)elem->call_data;
+  grpc_error *error = GRPC_ERROR_NONE;
+  static const char *error_name = "Failed processing incoming headers";
+
+  if (b->idx.named.method != NULL) {
+    if (grpc_mdelem_eq(b->idx.named.method->md, GRPC_MDELEM_METHOD_POST)) {
+      *calld->recv_initial_metadata_flags &=
+          ~(GRPC_INITIAL_METADATA_CACHEABLE_REQUEST |
+            GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST);
+    } else if (grpc_mdelem_eq(b->idx.named.method->md,
+                              GRPC_MDELEM_METHOD_PUT)) {
+      *calld->recv_initial_metadata_flags &=
+          ~GRPC_INITIAL_METADATA_CACHEABLE_REQUEST;
+      *calld->recv_initial_metadata_flags |=
+          GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST;
+    } else if (grpc_mdelem_eq(b->idx.named.method->md,
+                              GRPC_MDELEM_METHOD_GET)) {
+      *calld->recv_initial_metadata_flags |=
+          GRPC_INITIAL_METADATA_CACHEABLE_REQUEST;
+      *calld->recv_initial_metadata_flags &=
+          ~GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST;
+    } else {
+      add_error(error_name, &error,
+                grpc_attach_md_to_error(
+                    GRPC_ERROR_CREATE_FROM_STATIC_STRING("Bad header"),
+                    b->idx.named.method->md));
+    }
+    grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.method);
+  } else {
+    add_error(
+        error_name, &error,
+        grpc_error_set_str(
+            GRPC_ERROR_CREATE_FROM_STATIC_STRING("Missing header"),
+            GRPC_ERROR_STR_KEY, grpc_slice_from_static_string(":method")));
+  }
+
+  if (b->idx.named.te != NULL) {
+    if (!grpc_mdelem_eq(b->idx.named.te->md, GRPC_MDELEM_TE_TRAILERS)) {
+      add_error(error_name, &error,
+                grpc_attach_md_to_error(
+                    GRPC_ERROR_CREATE_FROM_STATIC_STRING("Bad header"),
+                    b->idx.named.te->md));
+    }
+    grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.te);
+  } else {
+    add_error(error_name, &error,
+              grpc_error_set_str(
+                  GRPC_ERROR_CREATE_FROM_STATIC_STRING("Missing header"),
+                  GRPC_ERROR_STR_KEY, grpc_slice_from_static_string("te")));
+  }
+
+  if (b->idx.named.scheme != NULL) {
+    if (!grpc_mdelem_eq(b->idx.named.scheme->md, GRPC_MDELEM_SCHEME_HTTP) &&
+        !grpc_mdelem_eq(b->idx.named.scheme->md, GRPC_MDELEM_SCHEME_HTTPS) &&
+        !grpc_mdelem_eq(b->idx.named.scheme->md, GRPC_MDELEM_SCHEME_GRPC)) {
+      add_error(error_name, &error,
+                grpc_attach_md_to_error(
+                    GRPC_ERROR_CREATE_FROM_STATIC_STRING("Bad header"),
+                    b->idx.named.scheme->md));
+    }
+    grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.scheme);
+  } else {
+    add_error(
+        error_name, &error,
+        grpc_error_set_str(
+            GRPC_ERROR_CREATE_FROM_STATIC_STRING("Missing header"),
+            GRPC_ERROR_STR_KEY, grpc_slice_from_static_string(":scheme")));
+  }
+
+  if (b->idx.named.content_type != NULL) {
+    if (!grpc_mdelem_eq(b->idx.named.content_type->md,
+                        GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC)) {
+      if (grpc_slice_buf_start_eq(GRPC_MDVALUE(b->idx.named.content_type->md),
+                                  EXPECTED_CONTENT_TYPE,
+                                  EXPECTED_CONTENT_TYPE_LENGTH) &&
+          (GRPC_SLICE_START_PTR(GRPC_MDVALUE(
+               b->idx.named.content_type->md))[EXPECTED_CONTENT_TYPE_LENGTH] ==
+               '+' ||
+           GRPC_SLICE_START_PTR(GRPC_MDVALUE(
+               b->idx.named.content_type->md))[EXPECTED_CONTENT_TYPE_LENGTH] ==
+               ';')) {
+        /* Although the C implementation doesn't (currently) generate them,
+           any custom +-suffix is explicitly valid. */
+        /* TODO(klempner): We should consider preallocating common values such
+           as +proto or +json, or at least stashing them if we see them. */
+        /* TODO(klempner): Should we be surfacing this to application code? */
+      } else {
+        /* TODO(klempner): We're currently allowing this, but we shouldn't
+           see it without a proxy so log for now. */
+        char *val = grpc_dump_slice(GRPC_MDVALUE(b->idx.named.content_type->md),
+                                    GPR_DUMP_ASCII);
+        gpr_log(GPR_INFO, "Unexpected content-type '%s'", val);
+        gpr_free(val);
+      }
+    }
+    grpc_metadata_batch_remove(exec_ctx, b, b->idx.named.content_type);
+  }
+
+  if (b->idx.named.path == NULL) {
+    add_error(error_name, &error,
+              grpc_error_set_str(
+                  GRPC_ERROR_CREATE_FROM_STATIC_STRING("Missing header"),
+                  GRPC_ERROR_STR_KEY, grpc_slice_from_static_string(":path")));
+  } else if (*calld->recv_initial_metadata_flags &
+             GRPC_INITIAL_METADATA_CACHEABLE_REQUEST) {
+    /* We have a cacheable request made with GET verb. The path contains the
+     * query parameter which is base64 encoded request payload. */
+    const char k_query_separator = '?';
+    grpc_slice path_slice = GRPC_MDVALUE(b->idx.named.path->md);
+    uint8_t *path_ptr = (uint8_t *)GRPC_SLICE_START_PTR(path_slice);
+    size_t path_length = GRPC_SLICE_LENGTH(path_slice);
+    /* offset of the character '?' */
+    size_t offset = 0;
+    for (offset = 0; offset < path_length && *path_ptr != k_query_separator;
+         path_ptr++, offset++)
+      ;
+    if (offset < path_length) {
+      grpc_slice query_slice =
+          grpc_slice_sub(path_slice, offset + 1, path_length);
+
+      /* substitute path metadata with just the path (not query) */
+      grpc_mdelem mdelem_path_without_query = grpc_mdelem_from_slices(
+          exec_ctx, GRPC_MDSTR_PATH, grpc_slice_sub(path_slice, 0, offset));
+
+      grpc_metadata_batch_substitute(exec_ctx, b, b->idx.named.path,
+                                     mdelem_path_without_query);
+
+      /* decode payload from query and add to the slice buffer to be returned */
+      const int k_url_safe = 1;
+      grpc_slice_buffer_add(
+          &calld->read_slice_buffer,
+          grpc_base64_decode_with_len(
+              exec_ctx, (const char *)GRPC_SLICE_START_PTR(query_slice),
+              GRPC_SLICE_LENGTH(query_slice), k_url_safe));
+      grpc_slice_buffer_stream_init(&calld->read_stream,
+                                    &calld->read_slice_buffer, 0);
+      calld->seen_path_with_query = true;
+      grpc_slice_unref_internal(exec_ctx, query_slice);
+    } else {
+      gpr_log(GPR_ERROR, "GET request without QUERY");
+    }
+  }
+
+  if (b->idx.named.host != NULL && b->idx.named.authority == NULL) {
+    grpc_linked_mdelem *el = b->idx.named.host;
+    grpc_mdelem md = GRPC_MDELEM_REF(el->md);
+    grpc_metadata_batch_remove(exec_ctx, b, el);
+    add_error(
+        error_name, &error,
+        grpc_metadata_batch_add_head(
+            exec_ctx, b, el, grpc_mdelem_from_slices(
+                                 exec_ctx, GRPC_MDSTR_AUTHORITY,
+                                 grpc_slice_ref_internal(GRPC_MDVALUE(md)))));
+    GRPC_MDELEM_UNREF(exec_ctx, md);
+  }
+
+  if (b->idx.named.authority == NULL) {
+    add_error(
+        error_name, &error,
+        grpc_error_set_str(
+            GRPC_ERROR_CREATE_FROM_STATIC_STRING("Missing header"),
+            GRPC_ERROR_STR_KEY, grpc_slice_from_static_string(":authority")));
+  }
+
+  return error;
+}
+
+static void hs_on_recv(grpc_exec_ctx *exec_ctx, void *user_data,
+                       grpc_error *err) {
+  grpc_call_element *elem = (grpc_call_element *)user_data;
+  call_data *calld = (call_data *)elem->call_data;
+  if (err == GRPC_ERROR_NONE) {
+    err = server_filter_incoming_metadata(exec_ctx, elem,
+                                          calld->recv_initial_metadata);
+  } else {
+    GRPC_ERROR_REF(err);
+  }
+  GRPC_CLOSURE_RUN(exec_ctx, calld->on_done_recv, err);
+}
+
+static void hs_on_complete(grpc_exec_ctx *exec_ctx, void *user_data,
+                           grpc_error *err) {
+  grpc_call_element *elem = (grpc_call_element *)user_data;
+  call_data *calld = (call_data *)elem->call_data;
+  /* Call recv_message_ready if we got the payload via the path field */
+  if (calld->seen_path_with_query && calld->recv_message_ready != NULL) {
+    *calld->pp_recv_message = calld->payload_bin_delivered
+                                  ? NULL
+                                  : (grpc_byte_stream *)&calld->read_stream;
+    // Re-enter call combiner for recv_message_ready, since the surface
+    // code will release the call combiner for each callback it receives.
+    GRPC_CALL_COMBINER_START(exec_ctx, calld->call_combiner,
+                             calld->recv_message_ready, GRPC_ERROR_REF(err),
+                             "resuming recv_message_ready from on_complete");
+    calld->recv_message_ready = NULL;
+    calld->payload_bin_delivered = true;
+  }
+  GRPC_CLOSURE_RUN(exec_ctx, calld->on_complete, GRPC_ERROR_REF(err));
+}
+
+static void hs_recv_message_ready(grpc_exec_ctx *exec_ctx, void *user_data,
+                                  grpc_error *err) {
+  grpc_call_element *elem = (grpc_call_element *)user_data;
+  call_data *calld = (call_data *)elem->call_data;
+  if (calld->seen_path_with_query) {
+    // Do nothing. This is probably a GET request, and payload will be
+    // returned in hs_on_complete callback.
+    // Note that we release the call combiner here, so that other
+    // callbacks can run.
+    GRPC_CALL_COMBINER_STOP(exec_ctx, calld->call_combiner,
+                            "pausing recv_message_ready until on_complete");
+  } else {
+    GRPC_CLOSURE_RUN(exec_ctx, calld->recv_message_ready, GRPC_ERROR_REF(err));
+  }
+}
+
+static grpc_error *hs_mutate_op(grpc_exec_ctx *exec_ctx,
+                                grpc_call_element *elem,
+                                grpc_transport_stream_op_batch *op) {
+  /* grab pointers to our data from the call element */
+  call_data *calld = (call_data *)elem->call_data;
+
+  if (op->send_initial_metadata) {
+    grpc_error *error = GRPC_ERROR_NONE;
+    static const char *error_name = "Failed sending initial metadata";
+    add_error(
+        error_name, &error,
+        grpc_metadata_batch_add_head(
+            exec_ctx, op->payload->send_initial_metadata.send_initial_metadata,
+            &calld->status, GRPC_MDELEM_STATUS_200));
+    add_error(
+        error_name, &error,
+        grpc_metadata_batch_add_tail(
+            exec_ctx, op->payload->send_initial_metadata.send_initial_metadata,
+            &calld->content_type,
+            GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC));
+    add_error(error_name, &error,
+              server_filter_outgoing_metadata(
+                  exec_ctx, elem,
+                  op->payload->send_initial_metadata.send_initial_metadata));
+    if (error != GRPC_ERROR_NONE) return error;
+  }
+
+  if (op->recv_initial_metadata) {
+    /* substitute our callback for the higher callback */
+    GPR_ASSERT(op->payload->recv_initial_metadata.recv_flags != NULL);
+    calld->recv_initial_metadata =
+        op->payload->recv_initial_metadata.recv_initial_metadata;
+    calld->recv_initial_metadata_flags =
+        op->payload->recv_initial_metadata.recv_flags;
+    calld->on_done_recv =
+        op->payload->recv_initial_metadata.recv_initial_metadata_ready;
+    op->payload->recv_initial_metadata.recv_initial_metadata_ready =
+        &calld->hs_on_recv;
+  }
+
+  if (op->recv_message) {
+    calld->recv_message_ready = op->payload->recv_message.recv_message_ready;
+    calld->pp_recv_message = op->payload->recv_message.recv_message;
+    if (op->payload->recv_message.recv_message_ready) {
+      op->payload->recv_message.recv_message_ready =
+          &calld->hs_recv_message_ready;
+    }
+    if (op->on_complete) {
+      calld->on_complete = op->on_complete;
+      op->on_complete = &calld->hs_on_complete;
+    }
+  }
+
+  if (op->send_trailing_metadata) {
+    grpc_error *error = server_filter_outgoing_metadata(
+        exec_ctx, elem,
+        op->payload->send_trailing_metadata.send_trailing_metadata);
+    if (error != GRPC_ERROR_NONE) return error;
+  }
+
+  return GRPC_ERROR_NONE;
+}
+
+static void hs_start_transport_stream_op_batch(
+    grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
+    grpc_transport_stream_op_batch *op) {
+  call_data *calld = (call_data *)elem->call_data;
+  GPR_TIMER_BEGIN("hs_start_transport_stream_op_batch", 0);
+  grpc_error *error = hs_mutate_op(exec_ctx, elem, op);
+  if (error != GRPC_ERROR_NONE) {
+    grpc_transport_stream_op_batch_finish_with_failure(exec_ctx, op, error,
+                                                       calld->call_combiner);
+  } else {
+    grpc_call_next_op(exec_ctx, elem, op);
+  }
+  GPR_TIMER_END("hs_start_transport_stream_op_batch", 0);
+}
+
+/* Constructor for call_data */
+static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
+                                  grpc_call_element *elem,
+                                  const grpc_call_element_args *args) {
+  /* grab pointers to our data from the call element */
+  call_data *calld = (call_data *)elem->call_data;
+  /* initialize members */
+  calld->call_combiner = args->call_combiner;
+  GRPC_CLOSURE_INIT(&calld->hs_on_recv, hs_on_recv, elem,
+                    grpc_schedule_on_exec_ctx);
+  GRPC_CLOSURE_INIT(&calld->hs_on_complete, hs_on_complete, elem,
+                    grpc_schedule_on_exec_ctx);
+  GRPC_CLOSURE_INIT(&calld->hs_recv_message_ready, hs_recv_message_ready, elem,
+                    grpc_schedule_on_exec_ctx);
+  grpc_slice_buffer_init(&calld->read_slice_buffer);
+  return GRPC_ERROR_NONE;
+}
+
+/* Destructor for call_data */
+static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
+                              const grpc_call_final_info *final_info,
+                              grpc_closure *ignored) {
+  call_data *calld = (call_data *)elem->call_data;
+  grpc_slice_buffer_destroy_internal(exec_ctx, &calld->read_slice_buffer);
+}
+
+/* Constructor for channel_data */
+static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
+                                     grpc_channel_element *elem,
+                                     grpc_channel_element_args *args) {
+  GPR_ASSERT(!args->is_last);
+  return GRPC_ERROR_NONE;
+}
+
+/* Destructor for channel data */
+static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
+                                 grpc_channel_element *elem) {}
+
+const grpc_channel_filter grpc_http_server_filter = {
+    hs_start_transport_stream_op_batch,
+    grpc_channel_next_op,
+    sizeof(call_data),
+    init_call_elem,
+    grpc_call_stack_ignore_set_pollset_or_pollset_set,
+    destroy_call_elem,
+    sizeof(channel_data),
+    init_channel_elem,
+    destroy_channel_elem,
+    grpc_channel_next_get_info,
+    "http-server"};