drivers/console/telnet: Provide minimal input handling.

Telnet "Interpret As Command" (IAC) code is ignored.

Change-Id: I882397389d77b8adfcbce62fbd9654c0b0412ae3
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>

2 files changed, 100 insertions, 0 deletions

diff --git a/drivers/console/telnet_console.c b/drivers/console/telnet_console.c
index d9a06d7a1..8c1840f60 100644
--- a/drivers/console/telnet_console.c
+++ b/drivers/console/telnet_console.c
@@ -24,6 +24,7 @@
 #include <init.h>
 #include <misc/printk.h>
 
+#include <console/console.h>
 #include <net/buf.h>
 #include <net/nbuf.h>
 #include <net/net_ip.h>
@@ -38,6 +39,8 @@
 #define TELNET_TIMEOUT		K_MSEC(CONFIG_TELNET_CONSOLE_SEND_TIMEOUT)
 #define TELNET_THRESHOLD	CONFIG_TELNET_CONSOLE_SEND_THRESHOLD
 
+#define TELNET_MIN_MSG		2
+
 /* These 2 structures below are used to store the console output
  * before sending it to the client. This is done to keep some
  * reactivity: the ring buffer is non-protected, if first line has
@@ -78,6 +81,9 @@ static struct net_context *client_cnx;
 static struct net_buf *out_buf;
 static int (*orig_printk_hook)(int);
 
+static struct k_fifo *avail_queue;
+static struct k_fifo *input_queue;
+
 extern void __printk_hook_install(int (*fn)(int));
 extern void *__printk_get_hook(void);
 
@@ -236,6 +242,52 @@ static inline bool telnet_send(void)
 	return true;
 }
 
+static inline void telnet_handle_input(struct net_buf *buf)
+{
+	struct console_input *input;
+	uint16_t len, offset, pos;
+	uint8_t *l_start;
+
+	len = net_nbuf_appdatalen(buf);
+	if (len > CONSOLE_MAX_LINE_LEN || len < TELNET_MIN_MSG) {
+		return;
+	}
+
+	/* Telnet commands are ignored for now
+	 * These are recognized by matching the IAC byte
+	 * (IAC: Intepret As Command) which value is 255
+	 */
+	l_start = net_nbuf_appdata(buf);
+	if (*l_start == 255) {
+		return;
+	}
+
+	if (!avail_queue || !input_queue) {
+		return;
+	}
+
+	input = k_fifo_get(avail_queue, K_NO_WAIT);
+	if (!input) {
+		return;
+	}
+
+	offset = net_buf_frags_len(buf) - len;
+	net_nbuf_read(buf->frags, offset, &pos, len, input->line);
+
+	/* LF/CR will be removed if only the line is not NUL terminated */
+	if (input->line[len-1] != '\0') {
+		if (input->line[len-1] == '\n') {
+			input->line[len-1] = '\0';
+		}
+
+		if (input->line[len-2] == '\r') {
+			input->line[len-2] = '\0';
+		}
+	}
+
+	k_fifo_put(input_queue, input);
+}
+
 static void telnet_recv(struct net_context *client,
 			struct net_buf *buf,
 			int status,
@@ -250,6 +302,8 @@ static void telnet_recv(struct net_context *client,
 		return;
 	}
 
+	telnet_handle_input(buf);
+
 	net_buf_unref(buf);
 }
 
@@ -343,6 +397,15 @@ error:
 	}
 }
 
+void telnet_register_input(struct k_fifo *avail, struct k_fifo *lines,
+			   uint8_t (*completion)(char *str, uint8_t len))
+{
+	ARG_UNUSED(completion);
+
+	avail_queue = avail;
+	input_queue = lines;
+}
+
 static int telnet_console_init(struct device *arg)
 {
 #ifdef CONFIG_NET_IPV4
diff --git a/include/drivers/console/telnet_console.h b/include/drivers/console/telnet_console.h
new file mode 100644
index 000000000..fe983dcf4
--- /dev/null
+++ b/include/drivers/console/telnet_console.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2017 Intel Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef __TELNET_CONSOLE_H__
+#define __TELNET_CONSOLE_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <kernel.h>
+
+/** @brief Register telnet input processing
+ *
+ *  Input processing is started when string is received in telnet server.
+ *  Carriage return is translated to NULL making string always NULL
+ *  terminated. Application before calling register function need to
+ *  initialize two fifo queues mentioned below.
+ *
+ *  @param avail k_fifo queue keeping available input slots
+ *  @param lines k_fifo queue of entered lines which to be processed
+ *         in the application code.
+ *  @param completion callback for tab completion of entered commands
+ *
+ *  @return N/A
+ */
+void telnet_register_input(struct k_fifo *avail, struct k_fifo *lines,
+			   uint8_t (*completion)(char *str, uint8_t len));
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __TELNET_CONSOLE_H__ */