introduce aepd

Signed-off-by: Andy Green <andy.green@linaro.org>

1 files changed, 218 insertions, 0 deletions

diff --git a/aepd/websocket-protocol.c b/aepd/websocket-protocol.c
new file mode 100644
index 0000000..cd81512
--- /dev/null
+++ b/aepd/websocket-protocol.c
@@ -0,0 +1,218 @@
+/*
+ * Author: Andy Green <andy.green@linaro.org> 
+ * Copyright (C) 2012 Linaro, LTD
+ * Libwebsocket demo code (C) 2010-2012 Andy Green <andy@warmcat.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ */
+
+#include "aepd.h"
+
+/*
+ * We take a strict whitelist approach to stop ../ attacks
+ */
+
+struct serveable {
+	const char *urlpath;
+	const char *mimetype;
+}; 
+
+static struct serveable whitelist[] = {
+	{ "/favicon.ico", "image/x-icon" },
+	{ "/linaro-logo-32.png", "image/png" },
+
+	/* last one is the default served if no match */
+	{ "/aepscope.html", "text/html" },
+};
+
+/* this protocol server (always the first one) just knows how to do HTTP */
+
+static int callback_http(struct libwebsocket_context *context,
+		struct libwebsocket *wsi,
+		enum libwebsocket_callback_reasons reason, void *user,
+							   void *in, size_t len)
+{
+	int n;
+	char buf[512];
+
+	switch (reason) {
+	case LWS_CALLBACK_HTTP:
+
+		for (n = 0; n < (sizeof(whitelist) / sizeof(whitelist[0]) - 1); n++)
+			if (in && strcmp(in, whitelist[n].urlpath) == 0)
+				break;
+
+		sprintf(buf, LOCAL_RESOURCE_PATH"%s", whitelist[n].urlpath);
+
+		if (libwebsockets_serve_http_file(wsi, buf, whitelist[n].mimetype))
+			fprintf(stderr, "Failed to send HTTP file\n");
+		break;
+
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+
+
+/* linaro_aepd_protocol */
+
+struct per_session_data__linaro_aepd {
+	struct libwebsocket *wsi;
+	unsigned long ringbuffer_tail;
+	double sam[MAX_PROBES * CHANNELS_PER_PROBE * 3];
+	int sam_valid;
+	int stride;
+};
+
+
+static int
+callback_linaro_aepd(struct libwebsocket_context *context,
+			struct libwebsocket *wsi,
+			enum libwebsocket_callback_reasons reason,
+					       void *user, void *in, size_t len)
+{
+	int n, m;
+	struct per_session_data__linaro_aepd *pss = user;
+	double sam[MAX_PROBES * CHANNELS_PER_PROBE * 3];
+	double d[10];
+	char buf[LWS_SEND_BUFFER_PRE_PADDING + 16384 + LWS_SEND_BUFFER_POST_PADDING];
+	char *p = &buf[LWS_SEND_BUFFER_PRE_PADDING];
+	int budget = 10;
+	unsigned long extent;
+
+	switch (reason) {
+
+	case LWS_CALLBACK_ESTABLISHED:
+		pss->ringbuffer_tail = aepd_shared->fifo_pos;
+		pss->sam_valid = 0;
+		pss->wsi = wsi;
+		pss->stride = 100;
+		break;
+
+	case LWS_CALLBACK_SERVER_WRITEABLE:
+
+		/*
+		 * aggregate up to 'budget' results in one websocket message
+		 */
+
+		while (budget--) {
+
+			if (pss->ringbuffer_tail <= aepd_shared->fifo_pos)
+				extent = aepd_shared->fifo_pos - pss->ringbuffer_tail;
+			else
+				extent = (aepd_shared->modulo_integer_chan_size - pss->ringbuffer_tail) + aepd_shared->fifo_pos;
+
+			if (extent < (pss->stride * aepd_shared->chans * sizeof(double) * 3)) {
+				budget = 0;
+				continue;
+			}
+
+			lseek(aepd_shared->fd_fifo_read, pss->ringbuffer_tail, SEEK_SET);
+			if (read(aepd_shared->fd_fifo_read, &sam[0], aepd_shared->chans * sizeof(double) * 3) < 0)
+				fprintf(stderr, "fifo read fail\n");
+
+			pss->ringbuffer_tail += (pss->stride * aepd_shared->chans * sizeof(double) * 3 );
+			if (pss->ringbuffer_tail > aepd_shared->modulo_integer_chan_size)
+				pss->ringbuffer_tail -=  aepd_shared->modulo_integer_chan_size;
+
+			if (pss->sam_valid) {
+
+				/*
+				 * Javascript can't cope with binary, so we must ascii-fy it
+				 */
+
+				m = 0;
+				for (n = 0; n < aepd_shared->chans; n++) {
+					p += sprintf(p, "%f %f %f",
+						(sam[m] - pss->sam[m]) / (double)pss->stride,
+						(sam[m + 1] - pss->sam[m + 1]) / (double)pss->stride,
+						(sam[m + 2] - pss->sam[m + 2]) / (double)pss->stride
+					);
+
+					if (n + 1 != aepd_shared->chans) {
+						*p++ = ',';
+						*p = '\0';
+					}
+					m += 3;
+				}
+
+				*p++ = ';';
+				*p = '\0';
+			}
+
+			memcpy(&pss->sam[0], &sam[0], aepd_shared->chans * sizeof(double) * 3);
+			pss->sam_valid = 1;
+		}
+
+		/*
+		 * if we generated something, send it.  We are guaranteed not to block
+		 * because we got here by POLLOUT seen on the socket
+		 */
+
+		if (p != &buf[LWS_SEND_BUFFER_PRE_PADDING]) {
+			n = libwebsocket_write(wsi, (unsigned char *)
+				   &buf[LWS_SEND_BUFFER_PRE_PADDING],
+				   p - &buf[LWS_SEND_BUFFER_PRE_PADDING], LWS_WRITE_TEXT);
+			if (n < 0) {
+				fprintf(stderr, "ERROR writing to socket");
+				return 1;
+			}
+			libwebsocket_callback_on_writable(context, wsi);
+		}
+
+		break;
+
+	case LWS_CALLBACK_RECEIVE:
+
+		switch (*(char *)in) {
+		case 'r':
+			if (sscanf(((char *)in) + 1, "%lf\n", &d[0]) == 1)
+				pss->stride = (int)d[0];
+			break;
+		}
+		break;
+
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+/* list of supported protocols and callbacks */
+
+struct libwebsocket_protocols protocols[] = {
+	/* first protocol must always be HTTP handler */
+
+	{
+		"http-only",		/* name */
+		callback_http,		/* callback */
+		0			/* per_session_data_size */
+	},
+	{
+		"linaro.aepd",
+		callback_linaro_aepd,
+		sizeof(struct per_session_data__linaro_aepd),
+	},
+	{
+		NULL, NULL, 0		/* End of list */
+	}
+};
+