websocket refactoring

Change-Id: Ia39ec6c01ce1fc6b3921b0433ab872d47ebdbbc4
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

1 files changed, 241 insertions, 79 deletions

diff --git a/src/afb-ws.c b/src/afb-ws.c
index 2ebfbb93..da248c89 100644
--- a/src/afb-ws.c
+++ b/src/afb-ws.c
@@ -29,6 +29,9 @@
 
 #include "utils-upoll.h"
 
+/*
+ * declaration of the websock interface for afb-ws
+ */
 static ssize_t aws_writev(struct afb_ws *ws, const struct iovec *iov, int iovcnt);
 static ssize_t aws_readv(struct afb_ws *ws, const struct iovec *iov, int iovcnt);
 static void aws_on_close(struct afb_ws *ws, uint16_t code, size_t size);
@@ -36,7 +39,7 @@ static void aws_on_text(struct afb_ws *ws, int last, size_t size);
 static void aws_on_binary(struct afb_ws *ws, int last, size_t size);
 static void aws_on_continue(struct afb_ws *ws, int last, size_t size);
 static void aws_on_readable(struct afb_ws *ws);
-static void aws_on_hangup(struct afb_ws *ws);
+static void aws_on_error(struct afb_ws *ws, uint16_t code, const void *data, size_t size);
 
 static struct websock_itf aws_itf = {
 	.writev = (void*)aws_writev,
@@ -48,54 +51,113 @@ static struct websock_itf aws_itf = {
 	.on_text = (void*)aws_on_text,
 	.on_binary = (void*)aws_on_binary,
 	.on_continue = (void*)aws_on_continue,
-	.on_extension = NULL
+	.on_extension = NULL,
+
+	.on_error = (void*)aws_on_error
 };
 
+/*
+ * a common scheme of buffer handling
+ */
 struct buf
 {
 	char *buffer;
 	size_t size;
 };
 
+/*
+ * the state
+ */
+enum state
+{
+	waiting,
+	reading_text,
+	reading_binary
+};
+
+/*
+ * the afb_ws structure
+ */
 struct afb_ws
 {
-	int fd;
-	enum { none, text, binary } type;
-	const struct afb_ws_itf *itf;
-	void *closure;
-	struct websock *ws;
-	struct upoll *up;
-	struct buf buffer;
+	int fd;			/* the socket file descriptor */
+	enum state state;	/* current state */
+	const struct afb_ws_itf *itf; /* the callback interface */
+	void *closure;		/* closure when calling the callbacks */
+	struct websock *ws;	/* the websock handler */
+	struct upoll *up;	/* the upoll handler for the socket */
+	struct buf buffer;	/* the last read fragment */
 };
 
+/*
+ * Returns the current buffer of 'ws' that is reset.
+ */
+static inline struct buf aws_pick_buffer(struct afb_ws *ws)
+{
+	struct buf result = ws->buffer;
+	ws->buffer.buffer = NULL;
+	ws->buffer.size = 0;
+	return result;
+}
+
+/*
+ * Disconnect the websocket 'ws' and calls on_hangup if
+ * 'call_on_hangup' is not null.
+ */
+static void aws_disconnect(struct afb_ws *ws, int call_on_hangup)
+{
+	struct websock *wsi = ws->ws;
+	if (wsi != NULL) {
+		ws->ws = NULL;
+		upoll_close(ws->up);
+		ws->up = NULL;
+		websock_destroy(wsi);
+		free(aws_pick_buffer(ws).buffer);
+		ws->state = waiting;
+		if (call_on_hangup && ws->itf->on_hangup)
+			ws->itf->on_hangup(ws->closure);
+	}
+}
+
+/*
+ * Creates the afb_ws structure for the file descritor
+ * 'fd' and the callbacks described by the interface 'itf'
+ * and its 'closure'.
+ *
+ * Returns the handle for the afb_ws created or NULL on error.
+ */
 struct afb_ws *afb_ws_create(int fd, const struct afb_ws_itf *itf, void *closure)
 {
 	struct afb_ws *result;
 
 	assert(fd >= 0);
 
+	/* allocation */
 	result = malloc(sizeof * result);
 	if (result == NULL)
 		goto error;
 
+	/* init */
 	result->fd = fd;
-	result->type = none;
+	result->state = waiting;
 	result->itf = itf;
 	result->closure = closure;
+	result->buffer.buffer = NULL;
+	result->buffer.size = 0;
 
+	/* creates the websocket */
 	result->ws = websock_create_v13(&aws_itf, result);
 	if (result->ws == NULL)
 		goto error2;
 
+	/* creates the upoll */
 	result->up = upoll_open(result->fd, result);
 	if (result->up == NULL)
 		goto error3;
 
-	result->buffer.buffer = NULL;
-	result->buffer.size = 0;
-
+	/* init the upoll */
 	upoll_on_readable(result->up, (void*)aws_on_readable);
-	upoll_on_hangup(result->up, (void*)aws_on_hangup);
+	upoll_on_hangup(result->up, (void*)afb_ws_hangup);
 
 	return result;
 
@@ -104,35 +166,92 @@ error3:
 error2:
 	free(result);
 error:
-	close(fd);
 	return NULL;
 }
 
-void afb_ws_disconnect(struct afb_ws *ws)
+/*
+ * Destroys the websocket 'ws'
+ * It first hangup (but without calling on_hangup for safety reasons)
+ * if needed.
+ */
+void afb_ws_destroy(struct afb_ws *ws)
 {
-	struct upoll *up = ws->up;
-	struct websock *wsi = ws->ws;
-	ws->up = NULL;
-	ws->ws = NULL;
-	upoll_close(up);
-	websock_destroy(wsi);
+	aws_disconnect(ws, 0);
+	free(ws);
 }
 
-void afb_ws_close(struct afb_ws *ws, uint16_t code)
+/*
+ * Hangup the websocket 'ws'
+ */
+void afb_ws_hangup(struct afb_ws *ws)
+{
+	aws_disconnect(ws, 1);
+}
+
+/*
+ * Sends a 'close' command to the endpoint of 'ws' with the 'code' and the
+ * 'reason' (that can be NULL and that else should not be greater than 123
+ * characters).
+ * Returns 0 on success or -1 in case of error.
+ */
+int afb_ws_close(struct afb_ws *ws, uint16_t code, const char *reason)
 {
-	websock_close_code(ws->ws, code, NULL, 0);
+	if (ws->ws == NULL) {
+		/* disconnected */
+		errno = EPIPE;
+		return -1;
+	}
+	return websock_close(ws->ws, code, reason, reason == NULL ? 0 : strlen(reason));
 }
 
-void afb_ws_text(struct afb_ws *ws, const char *text, size_t length)
+/*
+ * Sends a 'close' command to the endpoint of 'ws' with the 'code' and the
+ * 'reason' (that can be NULL and that else should not be greater than 123
+ * characters).
+ * Raise an error after 'close' command is sent.
+ * Returns 0 on success or -1 in case of error.
+ */
+int afb_ws_error(struct afb_ws *ws, uint16_t code, const char *reason)
 {
-	websock_text(ws->ws, 1, text, length);
+	if (ws->ws == NULL) {
+		/* disconnected */
+		errno = EPIPE;
+		return -1;
+	}
+	return websock_error(ws->ws, code, reason, reason == NULL ? 0 : strlen(reason));
 }
 
-void afb_ws_binary(struct afb_ws *ws, const void *data, size_t length)
+/*
+ * Sends a 'text' of 'length' to the endpoint of 'ws'.
+ * Returns 0 on success or -1 in case of error.
+ */
+int afb_ws_text(struct afb_ws *ws, const char *text, size_t length)
 {
-	websock_binary(ws->ws, 1, data, length);
+	if (ws->ws == NULL) {
+		/* disconnected */
+		errno = EPIPE;
+		return -1;
+	}
+	return websock_text(ws->ws, 1, text, length);
 }
 
+/*
+ * Sends a binary 'data' of 'length' to the endpoint of 'ws'.
+ * Returns 0 on success or -1 in case of error.
+ */
+int afb_ws_binary(struct afb_ws *ws, const void *data, size_t length)
+{
+	if (ws->ws == NULL) {
+		/* disconnected */
+		errno = EPIPE;
+		return -1;
+	}
+	return websock_binary(ws->ws, 1, data, length);
+}
+
+/*
+ * callback for writing data
+ */
 static ssize_t aws_writev(struct afb_ws *ws, const struct iovec *iov, int iovcnt)
 {
 	ssize_t rc;
@@ -142,6 +261,9 @@ static ssize_t aws_writev(struct afb_ws *ws, const struct iovec *iov, int iovcnt
 	return rc;
 }
 
+/*
+ * callback for reading data
+ */
 static ssize_t aws_readv(struct afb_ws *ws, const struct iovec *iov, int iovcnt)
 {
 	ssize_t rc;
@@ -155,25 +277,24 @@ static ssize_t aws_readv(struct afb_ws *ws, const struct iovec *iov, int iovcnt)
 	return rc;
 }
 
+/*
+ * callback on incoming data
+ */
 static void aws_on_readable(struct afb_ws *ws)
 {
-	if (websock_dispatch(ws->ws) < 0 && errno == EPIPE)
-		afb_ws_disconnect(ws);
-}
+	int rc;
 
-static void aws_on_hangup(struct afb_ws *ws)
-{
-	afb_ws_disconnect(ws);
-}
-
-static inline struct buf aws_pick_buffer(struct afb_ws *ws)
-{
-	struct buf result = ws->buffer;
-	ws->buffer.buffer = NULL;
-	ws->buffer.size = 0;
-	return result;
+	assert(ws->ws != NULL);
+	rc = websock_dispatch(ws->ws);
+	if (rc < 0 && errno == EPIPE)
+		afb_ws_hangup(ws);
 }
 
+/*
+ * Reads from the websocket handled by 'ws' data of length 'size'
+ * and append it to the current buffer of 'ws'.
+ * Returns 0 in case of error or 1 in case of success.
+ */
 static int aws_read(struct afb_ws *ws, size_t size)
 {
 	ssize_t sz;
@@ -192,66 +313,107 @@ static int aws_read(struct afb_ws *ws, size_t size)
 	return 1;
 }
 
+/*
+ * Callback when 'close' command received from 'ws' with 'code' and 'size'.
+ */
 static void aws_on_close(struct afb_ws *ws, uint16_t code, size_t size)
 {
 	struct buf b;
 
-	ws->type = none;
-	if (ws->itf->on_close == NULL)
+	ws->state = waiting;
+	free(aws_pick_buffer(ws).buffer);
+	if (ws->itf->on_close == NULL) {
 		websock_drop(ws->ws);
+		afb_ws_hangup(ws);
+	} else if (!aws_read(ws, size))
+		ws->itf->on_close(ws->closure, code, NULL, 0);
 	else {
-		aws_read(ws, size);
 		b = aws_pick_buffer(ws);
 		ws->itf->on_close(ws->closure, code, b.buffer, b.size);
 	}
 }
 
+/*
+ * Drops any incoming data and send an error of 'code'
+ */
+static void aws_drop_error(struct afb_ws *ws, uint16_t code)
+{
+	ws->state = waiting;
+	free(aws_pick_buffer(ws).buffer);
+	websock_drop(ws->ws);
+	websock_error(ws->ws, code, NULL, 0);
+}
+
+/*
+ * Reads either text or binary data of 'size' from 'ws' eventually 'last'.
+ */
+static void aws_continue(struct afb_ws *ws, int last, size_t size)
+{
+	struct buf b;
+	int istxt;
+
+	if (!aws_read(ws, size))
+		aws_drop_error(ws, WEBSOCKET_CODE_ABNORMAL);
+	else if (last) {
+		istxt = ws->state == reading_text;
+		ws->state = waiting;
+		b = aws_pick_buffer(ws);
+		b.buffer[b.size] = 0;
+		(istxt ? ws->itf->on_text : ws->itf->on_binary)(ws->closure, b.buffer, b.size);
+	}
+}
+
+/*
+ * Callback when 'text' message received from 'ws' with 'size' and possibly 'last'.
+ */
 static void aws_on_text(struct afb_ws *ws, int last, size_t size)
 {
-	if (ws->type != none) {
-		websock_drop(ws->ws);
-		websock_close_code(ws->ws, WEBSOCKET_CODE_PROTOCOL_ERROR, NULL, 0);
-	} else if (ws->itf->on_text == NULL) {
-		websock_drop(ws->ws);
-		websock_close_code(ws->ws, WEBSOCKET_CODE_CANT_ACCEPT, NULL, 0);
-	} else {
-		ws->type = text;
-		aws_on_continue(ws, last, size);
+	if (ws->state != waiting)
+		aws_drop_error(ws, WEBSOCKET_CODE_PROTOCOL_ERROR);
+	else if (ws->itf->on_text == NULL)
+		aws_drop_error(ws, WEBSOCKET_CODE_CANT_ACCEPT);
+	else {
+		ws->state = reading_text;
+		aws_continue(ws, last, size);
 	}
 }
 
+/*
+ * Callback when 'binary' message received from 'ws' with 'size' and possibly 'last'.
+ */
 static void aws_on_binary(struct afb_ws *ws, int last, size_t size)
 {
-	if (ws->type != none) {
-		websock_drop(ws->ws);
-		websock_close_code(ws->ws, WEBSOCKET_CODE_PROTOCOL_ERROR, NULL, 0);
-	} else if (ws->itf->on_binary == NULL) {
-		websock_drop(ws->ws);
-		websock_close_code(ws->ws, WEBSOCKET_CODE_CANT_ACCEPT, NULL, 0);
-	} else {
-		ws->type = text;
-		aws_on_continue(ws, last, size);
+	if (ws->state != waiting)
+		aws_drop_error(ws, WEBSOCKET_CODE_PROTOCOL_ERROR);
+	else if (ws->itf->on_binary == NULL)
+		aws_drop_error(ws, WEBSOCKET_CODE_CANT_ACCEPT);
+	else {
+		ws->state = reading_binary;
+		aws_continue(ws, last, size);
 	}
 }
 
+/*
+ * Callback when 'close' command received from 'ws' with 'code' and 'size'.
+ */
 static void aws_on_continue(struct afb_ws *ws, int last, size_t size)
 {
-	struct buf b;
-	int istxt;
+	if (ws->state == waiting)
+		aws_drop_error(ws, WEBSOCKET_CODE_PROTOCOL_ERROR);
+	else
+		aws_continue(ws, last, size);
+}
 
-	if (ws->type == none) {
-		websock_drop(ws->ws);
-		websock_close_code(ws->ws, WEBSOCKET_CODE_PROTOCOL_ERROR, NULL, 0);
-	} else {
-		if (!aws_read(ws, size)) {
-			aws_on_close(ws, WEBSOCKET_CODE_ABNORMAL, 0);
-		} else if (last) {
-			istxt = ws->type == text;
-			ws->type = none;
-			b = aws_pick_buffer(ws);
-			b.buffer[b.size] = 0;
-			(istxt ? ws->itf->on_text : ws->itf->on_binary)(ws->closure, b.buffer, b.size);
-		}
-	}
+/*
+ * Callback when 'close' command is sent to 'ws' with 'code' and 'size'.
+ */
+static void aws_on_error(struct afb_ws *ws, uint16_t code, const void *data, size_t size)
+{
+	if (ws->itf->on_error != NULL)
+		ws->itf->on_error(ws->closure, code, data, size);
+	else
+		afb_ws_hangup(ws);
 }
 
+
+