task #14281: Add MQTT client

Thanks to Erik Andersen
Taken from https://github.com/erian747/, branch mqtt, rev 5d59470

src/Filelists.mk

@@ -167,6 +167,9 @@ NETBIOSNSFILES=$(LWIPDIR)/apps/netbiosns/netbiosns.c
 # TFTPFILES: TFTP server files
 TFTPFILES=$(LWIPDIR)/apps/tftp/tftp_server.c
 
+# MQTTFILES: MQTT client files
+MQTTFILES=$(LWIPDIR)/apps/mqtt/mqtt.c
+
 # LWIPAPPFILES: All LWIP APPs
 LWIPAPPFILES=$(SNMPFILES) \
 	$(HTTPDFILES) \
@@ -174,4 +177,5 @@ LWIPAPPFILES=$(SNMPFILES) \
 	$(SNTPFILES) \
 	$(MDNSFILES) \
 	$(NETBIOSNSFILES) \
-	$(TFTPFILES)
+	$(TFTPFILES) \
+	$(MQTTFILES)

src/include/lwip/apps/mqtt.h

@@ -0,0 +1,246 @@
+/**
+ * @file
+ * MQTT client
+ */
+
+/*
+ * Copyright (c) 2016 Erik Andersson
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Erik Andersson
+ *
+ */
+#ifndef LWIP_HDR_MQTT_CLIENT_H
+#define LWIP_HDR_MQTT_CLIENT_H
+
+#include "lwip/err.h"
+#include "lwip/opt.h"
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+/**
+ * Output ring-buffer size, must be able to fit largest outgoing publish message topic+payloads
+ */
+#ifndef MQTT_OUTPUT_RINGBUF_SIZE
+#define MQTT_OUTPUT_RINGBUF_SIZE 256
+#endif
+
+/**
+ * Number of bytes in receive buffer, must be at least the size of the longest incoming topic + 8
+ * If one wants to avoid fragmented incoming publish, set length to max incoming topic length + max payload length + 8
+ */
+#ifndef MQTT_VAR_HEADER_BUFFER_LEN
+#define MQTT_VAR_HEADER_BUFFER_LEN 128
+#endif
+
+/**
+ * Maximum number of pending subscribe, unsubscribe and publish requests to server .
+ */
+#ifndef MQTT_REQ_MAX_IN_FLIGHT
+#define MQTT_REQ_MAX_IN_FLIGHT 4
+#endif
+
+typedef struct mqtt_client_t mqtt_client_t;
+
+
+/*---------------------------------------------------------------------------------------------- */
+/* Connection with server */
+
+/** Client information and connection parameters */
+struct mqtt_connect_client_info_t {
+  /** Client identifier, must be set by caller */
+  const char *client_id;
+  /** User name and password, set to NULL if not used */
+  const char* client_user;
+  const char* client_pass;
+  /** keep alive time in seconds, 0 to disable keep alive functionality*/
+  u16_t keep_alive;
+  /** will topic, set to NULL if will is not to be used,
+      will_msg, will_qos and will retain are then ignored */
+  const char* will_topic;
+  const char* will_msg;
+  u8_t will_qos;
+  u8_t will_retain;
+};
+
+/** Connection status codes */
+typedef enum
+{
+  MQTT_CONNECT_ACCEPTED                 = 0,
+  MQTT_CONNECT_REFUSED_PROTOCOL_VERSION = 1,
+  MQTT_CONNECT_REFUSED_IDENTIFIER       = 2,
+  MQTT_CONNECT_REFUSED_SERVER           = 3,
+  MQTT_CONNECT_REFUSED_USERNAME_PASS    = 4,
+  MQTT_CONNECT_REFUSED_NOT_AUTHORIZED_  = 5,
+  MQTT_CONNECT_DISCONNECTED             = 256,
+  MQTT_CONNECT_TIMEOUT                  = 257
+} mqtt_connection_status_t;
+
+/** Function prototype for mqtt connection status callback. Called when
+ * client has connected to the server after initiating a mqtt connection attempt by
+ * calling mqtt_connect() or when connection is closed by server or an error
+ *
+ * @param client MQTT client itself
+ * @param arg Additional argument to pass to the callback function
+ * @param status Connect result code or disconnection notification @see mqtt_connection_status_t
+ *
+ */
+typedef void (*mqtt_connection_cb_t)(mqtt_client_t *client, void *arg, mqtt_connection_status_t status);
+
+
+/** Data callback flags */
+enum {
+  /** Flag set when last fragment of data arrives in data callback */
+  MQTT_DATA_FLAG_LAST = 1,
+};
+
+/** Function prototype for MQTT incoming publish data callback function. Called when data
+ * arrives to a subscribed topic @see mqtt_subscribe
+ *
+ * @param client MQTT client itself
+ * @param arg Additional argument to pass to the callback function
+ * @param data User data, pointed object, data may not be referenced after callback return,
+          NULL is passed when all publish data are delivered
+ * @param len Length of publish data fragment
+ * @param flags MQTT_DATA_FLAG_LAST set when this call contains the last part of data from publish message
+ *
+ */
+typedef void (*mqtt_incoming_data_cb_t)(void *arg, const u8_t *data, u16_t len, u8_t flags);
+
+
+/** Function prototype for MQTT incoming publish function. Called when an incoming publish
+ * arrives to a subscribed topic @see mqtt_subscribe
+ *
+ * @param client MQTT client itself
+ * @param arg Additional argument to pass to the callback function
+ * @param topic Zero terminated Topic text string, topic may not be referenced after callback return
+ * @param tot_len Total length of publish data, if set to 0 (no publish payload) data callback will not be invoked
+ * @return Optional numerical topic identifier to be used in data callback
+ */
+typedef void (*mqtt_incoming_publish_cb_t)(void *arg, const char *topic, u32_t tot_len);
+
+
+/** Function prototype for mqtt request callback. Called when a subscribe, unsubscribe
+ * or publish request has completed
+ * @param arg Pointer to user data supplied when invoking request
+ * @param err ERR_OK on success
+ *            ERR_TIMEOUT if no response was received within timeout,
+ *            ERR_ABRT if (un)subscribe was denied
+ */
+typedef void (*mqtt_request_cb_t)(void *arg, err_t err);
+
+
+/**
+ * Pending request item, binds application callback to pending server requests
+ */
+struct mqtt_request_t
+{
+  /** Next item in list, NULL means this is the last in chain,
+      next pointing at itself means request is unallocated */
+  struct mqtt_request_t *next;
+  /** Callback to upper layer */
+  mqtt_request_cb_t cb;
+  void *arg;
+  /** MQTT packet identifier */
+  u16_t pkt_id;
+  /** Expire time relative to element before this  */
+  u16_t timeout_diff;
+};
+
+/** MQTT client */
+struct mqtt_client_t
+{
+	/** Timers and timeouts */
+	u16_t cyclic_tick;
+  u16_t keep_alive;
+  u16_t server_watchdog;
+	/** Packet identifier generator*/
+	u16_t pkt_id_seq;
+  /** Packet identifier of pending incoming publish */
+  u16_t inpub_pkt_id;
+  /** Connection state */
+  u8_t conn_state;
+  struct tcp_pcb *conn;
+	/** Connection callback */
+	void *connect_arg;
+	mqtt_connection_cb_t connect_cb;
+  /** Pending requests to server */
+  struct mqtt_request_t *pend_req_queue;
+  struct mqtt_request_t req_list[MQTT_REQ_MAX_IN_FLIGHT];
+	void *inpub_arg;
+	/** Incoming data callback */
+	mqtt_incoming_data_cb_t data_cb;
+  mqtt_incoming_publish_cb_t pub_cb;
+  /** Input */
+  u32_t msg_idx;
+  u8_t rx_buffer[MQTT_VAR_HEADER_BUFFER_LEN];
+	/** Output ring-buffer */
+	struct mqtt_ringbuf_t {
+    u16_t put;
+    u16_t get;
+    u8_t buf[MQTT_OUTPUT_RINGBUF_SIZE];
+  } output;
+};
+
+
+/** Connect to server */
+err_t mqtt_client_connect(mqtt_client_t *client, const char *host, mqtt_connection_cb_t cb, void *arg,
+                   const struct mqtt_connect_client_info_t *client_info);
+
+/** Disconnect from server */
+void mqtt_disconnect(mqtt_client_t *client);
+
+/** Create new client */
+mqtt_client_t *mqtt_client_new(void);
+
+/** Check connection status */
+u8_t mqtt_client_is_connected(mqtt_client_t *client);
+
+/** Set callback to call for incoming publish */
+void mqtt_set_inpub_callback(mqtt_client_t *client, mqtt_incoming_publish_cb_t,
+                             mqtt_incoming_data_cb_t data_cb, void *arg);
+
+/** Common function for subscribe and unsubscribe */
+err_t mqtt_sub_unsub(mqtt_client_t *client, const char *topic, u8_t qos, mqtt_request_cb_t cb, void *arg, u8_t sub);
+
+/** Subscribe to topic */
+#define mqtt_subscribe(client, topic, qos, cb, arg) mqtt_sub_unsub(client, topic, qos, cb, arg, 1)
+/** Unsubscribe to topic */
+#define mqtt_unsubscribe(client, topic, cb, arg) mqtt_sub_unsub(client, topic, 0, cb, arg, 0)
+
+
+/** Publish data to topic */
+err_t mqtt_publish(mqtt_client_t *client, const char *topic, const void *payload, u16_t payload_length, u8_t qos, u8_t retain,
+                                    mqtt_request_cb_t cb, void *arg);
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif /* LWIP_HDR_MQTT_CLIENT_H */