altsvc: Receive ALTSVC frame

lib/includes/nghttp2/nghttp2.h

@@ -2377,6 +2377,26 @@ NGHTTP2_EXTERN void
 nghttp2_option_set_user_recv_extension_type(nghttp2_option *option,
                                             uint8_t type);
 
+/**
+ * @ function
+ *
+ * Sets extension frame type the application is willing to receive
+ * using builtin handler.  The |type| is the extension frame type to
+ * receive, and must be strictly greater than 0x9.  Otherwise, this
+ * function does nothing.  The application can call this function
+ * multiple times to set more than one frame type to receive.  The
+ * application does not have to call this function if it just sends
+ * extension frames.
+ *
+ * If same frame type is passed to both
+ * `nghttp2_option_set_builtin_recv_extension_type()` and
+ * `nghttp2_option_set_user_recv_extension_type()`, the latter takes
+ * precedence.
+ */
+NGHTTP2_EXTERN void
+nghttp2_option_set_builtin_recv_extension_type(nghttp2_option *option,
+                                               uint8_t type);
+
 /**
  * @function
  *
@@ -4123,7 +4143,7 @@ NGHTTP2_EXTERN int nghttp2_submit_extension(nghttp2_session *session,
  * The payload of ALTSVC frame.  ALTSVC frame is one of extension
  * frame.  If this frame is received, and
  * `nghttp2_option_set_user_recv_extension_type()` is not set, and
- * `nghttp2_option_set_recv_extension_type()` is set for
+ * `nghttp2_option_set_builtin_recv_extension_type()` is set for
  * :enum:`NGHTTP2_ALTSVC`, ``nghttp2_extension.payload`` will point to
  * this struct.
  *

lib/nghttp2_frame.c

@@ -215,7 +215,6 @@ void nghttp2_frame_altsvc_free(nghttp2_extension *frame, nghttp2_mem *mem) {
   /* We use the same buffer for altsvc->origin and
      altsvc->field_value. */
   nghttp2_mem_free(mem, altsvc->origin);
-  nghttp2_mem_free(mem, altsvc);
 }
 
 size_t nghttp2_frame_priority_len(uint8_t flags) {
@@ -723,6 +722,25 @@ int nghttp2_frame_pack_altsvc(nghttp2_bufs *bufs, nghttp2_extension *frame) {
   return 0;
 }
 
+void nghttp2_frame_unpack_altsvc_payload(nghttp2_extension *frame,
+                                         size_t origin_len, uint8_t *payload,
+                                         size_t payloadlen) {
+  nghttp2_ext_altsvc *altsvc;
+  uint8_t *p;
+
+  altsvc = frame->payload;
+  p = payload;
+
+  altsvc->origin = p;
+
+  p += origin_len;
+
+  altsvc->origin_len = origin_len;
+
+  altsvc->field_value = p;
+  altsvc->field_value_len = (size_t)(payload + payloadlen - p);
+}
+
 nghttp2_settings_entry *nghttp2_frame_iv_copy(const nghttp2_settings_entry *iv,
                                               size_t niv, nghttp2_mem *mem) {
   nghttp2_settings_entry *iv_copy;

lib/nghttp2_frame.h

@@ -72,7 +72,7 @@
 #define NGHTTP2_MAX_PADLEN 256
 
 /* Union of extension frame payload */
-typedef union { int dummy; } nghttp2_ext_frame_payload;
+typedef union { nghttp2_ext_altsvc altsvc; } nghttp2_ext_frame_payload;
 
 void nghttp2_frame_pack_frame_hd(uint8_t *buf, const nghttp2_frame_hd *hd);
 
@@ -378,6 +378,16 @@ void nghttp2_frame_unpack_window_update_payload(nghttp2_window_update *frame,
  */
 int nghttp2_frame_pack_altsvc(nghttp2_bufs *bufs, nghttp2_extension *ext);
 
+/*
+ * Unpacks ALTSVC wire format into |frame|.  The |payload| of
+ * |payloadlen| bytes contains frame payload.  This function assumes
+ * that frame->payload points to the nghttp2_ext_altsvc object.
+ *
+ * This function always succeeds and returns 0.
+ */
+void nghttp2_frame_unpack_altsvc_payload(nghttp2_extension *frame,
+                                         size_t origin_len, uint8_t *payload,
+                                         size_t payloadlen);
 /*
  * Initializes HEADERS frame |frame| with given values.  |frame| takes
  * ownership of |nva|, so caller must not free it. If |stream_id| is
@@ -456,10 +466,23 @@ void nghttp2_frame_extension_init(nghttp2_extension *frame, uint8_t type,
 
 void nghttp2_frame_extension_free(nghttp2_extension *frame);
 
+/*
+ * Initializes ALTSVC frame |frame| with given values.  This function
+ * assumes that frame->payload points to nghttp2_ext_altsvc object.
+ * Also |origin| and |field_value| are allocated in single buffer,
+ * starting |origin|.  On success, this function takes ownership of
+ * |origin|, so caller must not free it.
+ */
 void nghttp2_frame_altsvc_init(nghttp2_extension *frame, int32_t stream_id,
                                uint8_t *origin, size_t origin_len,
                                uint8_t *field_value, size_t field_value_len);
 
+/*
+ * Frees up resources under |frame|.  This function does not free
+ * nghttp2_ext_altsvc object pointed by frame->payload.  This function
+ * only frees origin pointed by nghttp2_ext_altsvc.origin.  Therefore,
+ * other fields must be allocated in the same buffer with origin.
+ */
 void nghttp2_frame_altsvc_free(nghttp2_extension *frame, nghttp2_mem *mem);
 
 /*

lib/nghttp2_option.c

@@ -63,6 +63,10 @@ void nghttp2_option_set_max_reserved_remote_streams(nghttp2_option *option,
   option->max_reserved_remote_streams = val;
 }
 
+static void set_ext_type(uint8_t *ext_types, uint8_t type) {
+  ext_types[type / 8] = (uint8_t)(ext_types[type / 8] | (1 << (type & 0x7)));
+}
+
 void nghttp2_option_set_user_recv_extension_type(nghttp2_option *option,
                                                  uint8_t type) {
   if (type < 10) {
@@ -70,8 +74,17 @@ void nghttp2_option_set_user_recv_extension_type(nghttp2_option *option,
   }
 
   option->opt_set_mask |= NGHTTP2_OPT_USER_RECV_EXT_TYPES;
-  option->user_recv_ext_types[type / 8] =
-      (uint8_t)(option->user_recv_ext_types[type / 8] | (1 << (type & 0x7)));
+  set_ext_type(option->user_recv_ext_types, type);
+}
+
+void nghttp2_option_set_builtin_recv_extension_type(nghttp2_option *option,
+                                                    uint8_t type) {
+  if (type < 10) {
+    return;
+  }
+
+  option->opt_set_mask |= NGHTTP2_OPT_BUILTIN_RECV_EXT_TYPES;
+  set_ext_type(option->builtin_recv_ext_types, type);
 }
 
 void nghttp2_option_set_no_auto_ping_ack(nghttp2_option *option, int val) {

lib/nghttp2_option.h

@@ -61,7 +61,8 @@ typedef enum {
   NGHTTP2_OPT_NO_HTTP_MESSAGING = 1 << 3,
   NGHTTP2_OPT_MAX_RESERVED_REMOTE_STREAMS = 1 << 4,
   NGHTTP2_OPT_USER_RECV_EXT_TYPES = 1 << 5,
-  NGHTTP2_OPT_NO_AUTO_PING_ACK = 1 << 6
+  NGHTTP2_OPT_NO_AUTO_PING_ACK = 1 << 6,
+  NGHTTP2_OPT_BUILTIN_RECV_EXT_TYPES = 1 << 7
 } nghttp2_option_flag;
 
 /**
@@ -101,6 +102,10 @@ struct nghttp2_option {
    * NGHTTP2_OPT_USER_RECV_EXT_TYPES
    */
   uint8_t user_recv_ext_types[32];
+  /**
+   * NGHTTP2_OPT_BUILTIN_RECV_EXT_TYPES
+   */
+  uint8_t builtin_recv_ext_types[32];
 };
 
 #endif /* NGHTTP2_OPTION_H */

lib/nghttp2_outbound_item.c

@@ -90,6 +90,8 @@ void nghttp2_outbound_item_free(nghttp2_outbound_item *item, nghttp2_mem *mem) {
       assert(0);
       break;
     }
+
+    nghttp2_mem_free(mem, frame->ext.payload);
   }
   }
 }

lib/nghttp2_session.c

@@ -142,6 +142,10 @@ static int session_detect_idle_stream(nghttp2_session *session,
   return 0;
 }
 
+static int check_ext_type_set(const uint8_t *ext_types, uint8_t type) {
+  return (ext_types[type / 8] & (1 << (type & 0x7))) > 0;
+}
+
 static int session_call_error_callback(nghttp2_session *session,
                                        const char *fmt, ...) {
   size_t bufsize;
@@ -316,7 +320,18 @@ static void session_inbound_frame_reset(nghttp2_session *session) {
     break;
   default:
     /* extension frame */
-    nghttp2_frame_extension_free(&iframe->frame.ext);
+    if (check_ext_type_set(session->user_recv_ext_types,
+                           iframe->frame.hd.type)) {
+      nghttp2_frame_extension_free(&iframe->frame.ext);
+    } else if (check_ext_type_set(session->builtin_recv_ext_types,
+                                  iframe->frame.hd.type)) {
+      switch (iframe->frame.hd.type) {
+      case NGHTTP2_ALTSVC:
+        nghttp2_frame_altsvc_free(&iframe->frame.ext, mem);
+        break;
+      }
+    }
+
     break;
   }
 
@@ -332,6 +347,8 @@ static void session_inbound_frame_reset(nghttp2_session *session) {
   nghttp2_buf_free(&iframe->lbuf, mem);
   nghttp2_buf_wrap_init(&iframe->lbuf, NULL, 0);
 
+  iframe->raw_lbuf = NULL;
+
   iframe->niv = 0;
   iframe->payloadleft = 0;
   iframe->padlen = 0;
@@ -474,6 +491,12 @@ static int session_new(nghttp2_session **session_ptr,
              sizeof((*session_ptr)->user_recv_ext_types));
     }
 
+    if (option->opt_set_mask & NGHTTP2_OPT_BUILTIN_RECV_EXT_TYPES) {
+      memcpy((*session_ptr)->builtin_recv_ext_types,
+             option->builtin_recv_ext_types,
+             sizeof((*session_ptr)->builtin_recv_ext_types));
+    }
+
     if ((option->opt_set_mask & NGHTTP2_OPT_NO_AUTO_PING_ACK) &&
         option->no_auto_ping_ack) {
       (*session_ptr)->opt_flags |= NGHTTP2_OPTMASK_NO_AUTO_PING_ACK;
@@ -4637,6 +4660,44 @@ static int session_process_window_update_frame(nghttp2_session *session) {
   return nghttp2_session_on_window_update_received(session, frame);
 }
 
+int nghttp2_session_on_altsvc_received(nghttp2_session *session,
+                                       nghttp2_frame *frame) {
+  nghttp2_ext_altsvc *altsvc;
+
+  altsvc = frame->ext.payload;
+
+  if (session->server) {
+    return 0;
+  }
+
+  if (frame->hd.stream_id == 0) {
+    if (altsvc->origin_len == 0) {
+      return 0;
+    }
+  } else if (altsvc->origin_len > 0) {
+    return 0;
+  }
+
+  return session_call_on_frame_received(session, frame);
+}
+
+static int session_process_altsvc_frame(nghttp2_session *session) {
+  nghttp2_inbound_frame *iframe = &session->iframe;
+  nghttp2_frame *frame = &iframe->frame;
+
+  frame->ext.payload = &iframe->ext_frame_payload.altsvc;
+
+  nghttp2_frame_unpack_altsvc_payload(
+      &frame->ext, nghttp2_get_uint16(iframe->sbuf.pos), iframe->lbuf.pos,
+      nghttp2_buf_len(&iframe->lbuf));
+
+  /* nghttp2_frame_unpack_altsvc_payload steals buffer from
+     iframe->lbuf */
+  nghttp2_buf_wrap_init(&iframe->lbuf, NULL, 0);
+
+  return nghttp2_session_on_altsvc_received(session, frame);
+}
+
 static int session_process_extension_frame(nghttp2_session *session) {
   int rv;
   nghttp2_inbound_frame *iframe = &session->iframe;
@@ -5480,25 +5541,59 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
 
         break;
       default:
-        DEBUGF(fprintf(stderr, "recv: unknown frame\n"));
+        DEBUGF(fprintf(stderr, "recv: extension frame\n"));
 
-        if (!session->callbacks.unpack_extension_callback ||
-            (session->user_recv_ext_types[iframe->frame.hd.type / 8] &
-             (1 << (iframe->frame.hd.type & 0x7))) == 0) {
-          /* Silently ignore unknown frame type. */
+        if (check_ext_type_set(session->user_recv_ext_types,
+                               iframe->frame.hd.type)) {
+          if (!session->callbacks.unpack_extension_callback) {
+            /* Silently ignore unknown frame type. */
+
+            busy = 1;
+
+            iframe->state = NGHTTP2_IB_IGN_PAYLOAD;
+
+            break;
+          }
 
           busy = 1;
 
-          iframe->state = NGHTTP2_IB_IGN_PAYLOAD;
+          iframe->state = NGHTTP2_IB_READ_EXTENSION_PAYLOAD;
 
           break;
-        }
+        } else if (check_ext_type_set(session->builtin_recv_ext_types,
+                                      iframe->frame.hd.type)) {
+          switch (iframe->frame.hd.type) {
+          case NGHTTP2_ALTSVC:
+            DEBUGF(fprintf(stderr, "recv: ALTSVC\n"));
 
-        busy = 1;
+            iframe->frame.hd.flags = NGHTTP2_FLAG_NONE;
 
-        iframe->state = NGHTTP2_IB_READ_EXTENSION_PAYLOAD;
+            if (iframe->payloadleft < 2) {
+              busy = 1;
+              iframe->state = NGHTTP2_IB_FRAME_SIZE_ERROR;
+              break;
+            }
 
-        break;
+            busy = 1;
+
+            iframe->state = NGHTTP2_IB_READ_NBYTE;
+            inbound_frame_set_mark(iframe, 2);
+
+            break;
+          default:
+            busy = 1;
+
+            iframe->state = NGHTTP2_IB_IGN_PAYLOAD;
+
+            break;
+          }
+        } else {
+          busy = 1;
+
+          iframe->state = NGHTTP2_IB_IGN_PAYLOAD;
+
+          break;
+        }
       }
 
       if (!on_begin_frame_called) {
@@ -5708,6 +5803,37 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
         session_inbound_frame_reset(session);
 
         break;
+      case NGHTTP2_ALTSVC: {
+        size_t origin_len;
+
+        origin_len = nghttp2_get_uint16(iframe->sbuf.pos);
+
+        DEBUGF(fprintf(stderr, "recv: origin_len=%zu\n", origin_len));
+
+        if (2 + origin_len > iframe->payloadleft) {
+          busy = 1;
+          iframe->state = NGHTTP2_IB_FRAME_SIZE_ERROR;
+          break;
+        }
+
+        if (iframe->frame.hd.length > 2) {
+          iframe->raw_lbuf =
+              nghttp2_mem_malloc(mem, iframe->frame.hd.length - 2);
+
+          if (iframe->raw_lbuf == NULL) {
+            return NGHTTP2_ERR_NOMEM;
+          }
+
+          nghttp2_buf_wrap_init(&iframe->lbuf, iframe->raw_lbuf,
+                                iframe->frame.hd.length);
+        }
+
+        busy = 1;
+
+        iframe->state = NGHTTP2_IB_READ_ALTSVC_PAYLOAD;
+
+        break;
+      }
       default:
         /* This is unknown frame */
         session_inbound_frame_reset(session);
@@ -6233,6 +6359,36 @@ ssize_t nghttp2_session_mem_recv(nghttp2_session *session, const uint8_t *in,
 
       session_inbound_frame_reset(session);
 
+      break;
+    case NGHTTP2_IB_READ_ALTSVC_PAYLOAD:
+      DEBUGF(fprintf(stderr, "recv: [IB_READ_ALTSVC_PAYLOAD]\n"));
+
+      readlen = inbound_frame_payload_readlen(iframe, in, last);
+
+      if (readlen > 0) {
+        iframe->lbuf.last = nghttp2_cpymem(iframe->lbuf.last, in, readlen);
+
+        iframe->payloadleft -= readlen;
+        in += readlen;
+      }
+
+      DEBUGF(fprintf(stderr, "recv: readlen=%zu, payloadleft=%zu\n", readlen,
+                     iframe->payloadleft));
+
+      if (iframe->payloadleft) {
+        assert(nghttp2_buf_avail(&iframe->lbuf) > 0);
+
+        break;
+      }
+
+      rv = session_process_altsvc_frame(session);
+
+      if (nghttp2_is_fatal(rv)) {
+        return rv;
+      }
+
+      session_inbound_frame_reset(session);
+
       break;
     }
 

lib/nghttp2_session.h

@@ -107,6 +107,7 @@ typedef enum {
   NGHTTP2_IB_READ_DATA,
   NGHTTP2_IB_IGN_DATA,
   NGHTTP2_IB_IGN_ALL,
+  NGHTTP2_IB_READ_ALTSVC_PAYLOAD,
   NGHTTP2_IB_READ_EXTENSION_PAYLOAD
 } nghttp2_inbound_state;
 
@@ -313,6 +314,7 @@ struct nghttp2_session {
      bit is set, it indicates that incoming frame with that type is
      passed to user defined callbacks, otherwise they are ignored. */
   uint8_t user_recv_ext_types[32];
+  uint8_t builtin_recv_ext_types[32];
 };
 
 /* Struct used when updating initial window size of each active
@@ -716,6 +718,19 @@ int nghttp2_session_on_goaway_received(nghttp2_session *session,
 int nghttp2_session_on_window_update_received(nghttp2_session *session,
                                               nghttp2_frame *frame);
 
+/*
+ * Called when ALTSVC is recieved, assuming |frame| is properly
+ * initialized.
+ *
+ * This function returns 0 if it succeeds, or one of the following
+ * negative error codes:
+ *
+ * NGHTTP2_ERR_CALLBACK_FAILURE
+ *   The callback function failed.
+ */
+int nghttp2_session_on_altsvc_received(nghttp2_session *session,
+                                       nghttp2_frame *frame);
+
 /*
  * Called when DATA is received, assuming |frame| is properly
  * initialized.

lib/nghttp2_submit.c

@@ -485,6 +485,7 @@ int nghttp2_submit_altsvc(nghttp2_session *session, uint8_t flags _U_,
   rv = nghttp2_session_add_item(session, item);
   if (rv != 0) {
     nghttp2_frame_altsvc_free(&frame->ext, mem);
+    nghttp2_mem_free(mem, frame->ext.payload);
     nghttp2_mem_free(mem, item);
 
     return rv;

src/nghttp.cc

@@ -118,6 +118,7 @@ Config::Config()
   nghttp2_option_new(&http2_option);
   nghttp2_option_set_peer_max_concurrent_streams(http2_option,
                                                  peer_max_concurrent_streams);
+  nghttp2_option_set_builtin_recv_extension_type(http2_option, NGHTTP2_ALTSVC);
 }
 
 Config::~Config() { nghttp2_option_del(http2_option); }