initial support for TCP client connections from uC

Makefile

@@ -30,7 +30,7 @@ ESPBAUD		?= 460800
 # --------------- chipset configuration   ---------------
 
 # Pick your flash size: "512KB" or "4MB"
-FLASH_SIZE ?= 4MB
+FLASH_SIZE ?= 512KB
 
 ifeq ("$(FLASH_SIZE)","512KB")
 # Winbond 25Q40 512KB flash, typ for esp-01 thru esp-11

html/home.html

@@ -44,6 +44,28 @@
 					</fieldset>
 				</div></div>
 			</div>
+			<div class="pure-g">
+				<div class="pure-u-1 pure-u-md-1-2"><div class="card">
+					<h1>HTTP service</h1>
+          <form action="#" id="httpform" class="pure-form">
+					  <legend>External web service configuration</legend>
+            <div class="form-horizontal">
+              <label>Enable serial port HTTP</label>
+              <input type="checkbox" name="http_enable"/>
+              <label>Send RSSI</label>
+              <input type="checkbox" name="send_rssi"/>
+            </div>
+            <div class="pure-form-stacked">
+              <label>Server hostname</label>
+              <input type="text" name="hostname"/>
+              <label>API key/passwd</label>
+              <input type="password" name="api_key"/>
+            </div>
+            <button id="special-button" type="submit"
+                    class="pure-button button-primary">Change!</button>
+          </form>
+				</div></div>
+			</div>
     </div>
   </div>
 </div>

serial/serbridge.c

@@ -13,20 +13,21 @@
 #include "serled.h"
 #include "config.h"
 #include "console.h"
+#include "tcpclient.h"
 
 static struct espconn serbridgeConn;
 static esp_tcp serbridgeTcp;
 static int8_t mcu_reset_pin, mcu_isp_pin;
 
-sint8  ICACHE_FLASH_ATTR espbuffsend(serbridgeConnData *conn, const char *data, uint16 len);
+static sint8 ICACHE_FLASH_ATTR espbuffsend(serbridgeConnData *conn, const char *data, uint16 len);
 
 // Connection pool
 serbridgeConnData connData[MAX_CONN];
-// Transmit buffers for the connection pool
-static char txbuffer[MAX_CONN][MAX_TXBUFFER];
-
 // Given a pointer to an espconn struct find the connection that correcponds to it
 static serbridgeConnData ICACHE_FLASH_ATTR *serbridgeFindConnData(void *arg) {
+	struct espconn *conn = arg;
+	return (serbridgeConnData *)conn->reverse;
+#if 0
 	for (int i=0; i<MAX_CONN; i++) {
 		if (connData[i].conn == (struct espconn *)arg) {
 			return &connData[i];
@@ -34,54 +35,10 @@ static serbridgeConnData ICACHE_FLASH_ATTR *serbridgeFindConnData(void *arg) {
 	}
 	//os_printf("FindConnData: Huh? Couldn't find connection for %p\n", arg);
 	return NULL; // not found, may be closed already...
+#endif
 }
 
-// Send all data in conn->txbuffer
+//===== TCP -> UART
-// returns result from espconn_sent if data in buffer or ESPCONN_OK (0)
-// Use only internally from espbuffsend and serbridgeSentCb
-static sint8 ICACHE_FLASH_ATTR sendtxbuffer(serbridgeConnData *conn) {
-	sint8 result = ESPCONN_OK;
-	if (conn->txbufferlen != 0) {
-		//os_printf("%d TX %d\n", system_get_time(), conn->txbufferlen);
-		conn->readytosend = false;
-		result = espconn_sent(conn->conn, (uint8_t*)conn->txbuffer, conn->txbufferlen);
-		conn->txbufferlen = 0;
-		if (result != ESPCONN_OK) {
-			os_printf("sendtxbuffer: espconn_sent error %d on conn %p\n", result, conn);
-		}
-	}
-	return result;
-}
-
-// espbuffsend adds data to the send buffer. If the previous send was completed it calls
-// sendtxbuffer and espconn_sent.
-// Returns ESPCONN_OK (0) for success, -128 if buffer is full or error from  espconn_sent
-// Use espbuffsend instead of espconn_sent as it solves the problem that espconn_sent must
-// only be called *after* receiving an espconn_sent_callback for the previous packet.
-sint8 ICACHE_FLASH_ATTR espbuffsend(serbridgeConnData *conn, const char *data, uint16 len) {
-	if (conn->txbufferlen + len > MAX_TXBUFFER) {
-		os_printf("espbuffsend: txbuffer full on conn %p\n", conn);
-		return -128;
-	}
-	os_memcpy(conn->txbuffer + conn->txbufferlen, data, len);
-	conn->txbufferlen += len;
-	if (conn->readytosend) {
-		return sendtxbuffer(conn);
-	} else {
-		//os_printf("%d QU %d\n", system_get_time(), conn->txbufferlen);
-	}
-	return ESPCONN_OK;
-}
-
-//callback after the data are sent
-static void ICACHE_FLASH_ATTR serbridgeSentCb(void *arg) {
-	serbridgeConnData *conn = serbridgeFindConnData(arg);
-	//os_printf("Sent callback on conn %p\n", conn);
-	if (conn == NULL) return;
-	//os_printf("%d ST\n", system_get_time());
-	conn->readytosend = true;
-	sendtxbuffer(conn); // send possible new data in txbuffer
-}
 
 // Telnet protocol characters
 #define IAC        255  // escape
@@ -189,7 +146,6 @@ void ICACHE_FLASH_ATTR serbridgeReset() {
 	} else os_printf("MCU reset: no pin\n");
 }
 
-
 // Receive callback
 static void ICACHE_FLASH_ATTR serbridgeRecvCb(void *arg, char *data, unsigned short len) {
 	serbridgeConnData *conn = serbridgeFindConnData(arg);
@@ -233,6 +189,9 @@ static void ICACHE_FLASH_ATTR serbridgeRecvCb(void *arg, char *data, unsigned sh
 		} else {
 			conn->conn_mode = cmTransparent;
 		}
+
+	// Process return data on TCP client connections
+	} else if (conn->conn_mode == cmTcpClient) {
 	}
 
 	// write the buffer to the uart
@@ -245,41 +204,181 @@ static void ICACHE_FLASH_ATTR serbridgeRecvCb(void *arg, char *data, unsigned sh
 	serledFlash(50); // short blink on serial LED
 }
 
+//===== UART -> TCP
+
+// Transmit buffers for the connection pool
+static char txbuffer[MAX_CONN][MAX_TXBUFFER];
+
+// Send all data in conn->txbuffer
+// returns result from espconn_sent if data in buffer or ESPCONN_OK (0)
+// Use only internally from espbuffsend and serbridgeSentCb
+static sint8 ICACHE_FLASH_ATTR sendtxbuffer(serbridgeConnData *conn) {
+	sint8 result = ESPCONN_OK;
+	if (conn->txbufferlen != 0) {
+		//os_printf("%d TX %d\n", system_get_time(), conn->txbufferlen);
+		conn->readytosend = false;
+		result = espconn_sent(conn->conn, (uint8_t*)conn->txbuffer, conn->txbufferlen);
+		conn->txbufferlen = 0;
+		if (result != ESPCONN_OK) {
+			os_printf("sendtxbuffer: espconn_sent error %d on conn %p\n", result, conn);
+		}
+	}
+	return result;
+}
+
+// espbuffsend adds data to the send buffer. If the previous send was completed it calls
+// sendtxbuffer and espconn_sent.
+// Returns ESPCONN_OK (0) for success, -128 if buffer is full or error from  espconn_sent
+// Use espbuffsend instead of espconn_sent as it solves the problem that espconn_sent must
+// only be called *after* receiving an espconn_sent_callback for the previous packet.
+static sint8 ICACHE_FLASH_ATTR espbuffsend(serbridgeConnData *conn, const char *data, uint16 len) {
+	if (conn->txbufferlen + len > MAX_TXBUFFER) {
+		os_printf("espbuffsend: txbuffer full on conn %p\n", conn);
+		return -128;
+	}
+	os_memcpy(conn->txbuffer + conn->txbufferlen, data, len);
+	conn->txbufferlen += len;
+	if (conn->readytosend) {
+		return sendtxbuffer(conn);
+	} else {
+		//os_printf("%d QU %d\n", system_get_time(), conn->txbufferlen);
+	}
+	return ESPCONN_OK;
+}
+
+//callback after the data are sent
+static void ICACHE_FLASH_ATTR
+serbridgeSentCb(void *arg) {
+	serbridgeConnData *conn = serbridgeFindConnData(arg);
+	//os_printf("Sent callback on conn %p\n", conn);
+	if (conn == NULL) return;
+	//os_printf("%d ST\n", system_get_time());
+	conn->readytosend = true;
+	sendtxbuffer(conn); // send possible new data in txbuffer
+}
+
+// TCP client connection state machine
+// This processes commands from the attached uC to open outboud TCP connections
+enum {
+	TC_idle,       // in-between commands
+	TC_newline,    // newline seen
+	TC_start,      // start character (~) seen
+	TC_cmd,        // command character (0) seen
+	TC_cmdLine,    // accumulating command
+	TC_tdata,      // data character (1-9) seen, and in text data mode
+};
+static uint8_t tcState = TC_newline;
+static uint8_t tcChan; // channel for current command (index into tcConn)
+
+#define CMD_MAX 256
+static char tcCmdBuf[CMD_MAX];
+static short tcCmdBufLen = 0;
+static char tcCmdChar;
+
+// scan a buffer for tcp client commands
+static int ICACHE_FLASH_ATTR
+tcpClientProcess(char *buf, int len)
+{
+	char *in=buf, *out=buf;
+	for (short i=0; i<len; i++) {
+		char c = *in++;
+		//os_printf("tcState=%d c=%c\n", tcState, c);
+		switch (tcState) {
+		case TC_idle:
+			if (c == '\n') tcState = TC_newline;
+			break;
+		case TC_newline: // saw newline, expect ~
+			if (c == '~') tcState = TC_start;
+			continue; // gobble up the ~
+		case TC_start: // saw ~, expect channel number
+			if (c == '0') {
+				tcState = TC_cmd;
+				continue;
+			} else if (c >= '1' && c <= '9') {
+				tcChan = c-'1';
+				tcState = TC_tdata;
+				continue;
+			}
+			*out++ = '~'; // make up for '~' we skipped
+			break;
+		case TC_cmd: // saw channel number 0 (command), expect command char
+			tcCmdChar = c;   // save command character
+			tcCmdBufLen = 0; // empty the command buffer
+			tcState = TC_cmdLine;
+			continue;
+		case TC_cmdLine: // accumulating command in buffer
+			if (c != '\n') {
+				if (tcCmdBufLen < CMD_MAX) tcCmdBuf[tcCmdBufLen++] = c;
+			} else {
+				tcpClientCommand(tcCmdChar, tcCmdBuf);
+				tcState = TC_newline;
+			}
+			continue;
+		case TC_tdata: // saw channel number, getting data characters
+			if (c != 0) {
+				tcpClientSendChar(tcChan, c);
+			} else {
+				tcpClientSendPush(tcChan);
+				tcState = TC_idle;
+			}
+			continue;
+		}
+		*out++ = c;
+	}
+	if (tcState != TC_idle) os_printf("tcState=%d\n", tcState);
+	return out-buf;
+}
+
+// callback with a buffer of characters that have arrived on the uart
+void ICACHE_FLASH_ATTR
+serbridgeUartCb(char *buf, int length) {
+	// push the buffer into the microcontroller console
+	for (int i=0; i<length; i++)
+		console_write_char(buf[i]);
+	// parse the buffer for TCP commands, this may remove characters from the buffer
+	length = tcpClientProcess(buf, length);
+	// push the buffer into each open connection
+	if (length > 0) {
+		for (int i = 0; i < MAX_CONN; ++i) {
+			if (connData[i].conn && connData[i].conn_mode != cmTcpClient) {
+				espbuffsend(&connData[i], buf, length);
+			}
+		}
+	}
+	serledFlash(50); // short blink on serial LED
+}
+
+//===== Connect / disconnect
+
 // Error callback (it's really poorly named, it's not a "connection reconnected" callback,
 // it's really a "connection broken, please reconnect" callback)
 static void ICACHE_FLASH_ATTR serbridgeReconCb(void *arg, sint8 err) {
-	serbridgeConnData *conn=serbridgeFindConnData(arg);
+	serbridgeConnData *sbConn = serbridgeFindConnData(arg);
-	if (conn == NULL) return;
+	if (sbConn == NULL) return;
 	// Close the connection
-	espconn_disconnect(conn->conn);
+	espconn_disconnect(sbConn->conn);
-	conn->conn = NULL;
+	// free connection slot
+	sbConn->conn = NULL;
 }
 
 // Disconnection callback
 static void ICACHE_FLASH_ATTR serbridgeDisconCb(void *arg) {
-	// Iterate through all the connections and deallocate the ones that are in a state that
+	serbridgeConnData *sbConn = serbridgeFindConnData(arg);
-	// indicates that they're closed
+	if (sbConn == NULL) return;
-	for (int i=0; i<MAX_CONN; i++) {
+	// send reset to arduino/ARM
-		if (connData[i].conn != NULL &&
+	if (sbConn->conn_mode == cmAVR && mcu_reset_pin >= 0) {
-		   (connData[i].conn->state == ESPCONN_NONE || connData[i].conn->state == ESPCONN_CLOSE))
+		GPIO_OUTPUT_SET(mcu_reset_pin, 0);
-		{
+		os_delay_us(100L);
-			if (connData[i].conn_mode == cmAVR) {
+		GPIO_OUTPUT_SET(mcu_reset_pin, 1);
-				// send reset to arduino/ARM
-				if (mcu_reset_pin >= 0) {
-					GPIO_OUTPUT_SET(mcu_reset_pin, 0);
-					os_delay_us(100L);
-					GPIO_OUTPUT_SET(mcu_reset_pin, 1);
-				}
-			}
-			connData[i].conn = NULL;
-		}
 	}
+	// free connection slot
+	sbConn->conn = NULL;
 }
 
 // New connection callback, use one of the connection descriptors, if we have one left.
 static void ICACHE_FLASH_ATTR serbridgeConnectCb(void *arg) {
 	struct espconn *conn = arg;
-	//Find empty conndata in pool
+	// Find empty conndata in pool
 	int i;
 	for (i=0; i<MAX_CONN; i++) if (connData[i].conn==NULL) break;
 	os_printf("Accept port 23, conn=%p, pool slot %d\n", conn, i);
@@ -290,7 +389,8 @@ static void ICACHE_FLASH_ATTR serbridgeConnectCb(void *arg) {
 		return;
 	}
 
-	connData[i].conn=conn;
+	conn->reverse = connData+i;
+	connData[i].conn = conn;
 	connData[i].txbufferlen = 0;
 	connData[i].readytosend = true;
 	connData[i].telnet_state = 0;
@@ -304,20 +404,7 @@ static void ICACHE_FLASH_ATTR serbridgeConnectCb(void *arg) {
 	espconn_set_opt(conn, ESPCONN_REUSEADDR|ESPCONN_NODELAY);
 }
 
-// callback with a buffer of characters that have arrived on the uart
+//===== Initialization
-void ICACHE_FLASH_ATTR
-serbridgeUartCb(char *buf, int length) {
-	// push the buffer into the microcontroller console
-	for (int i=0; i<length; i++)
-		console_write_char(buf[i]);
-	// push the buffer into each open connection
-	for (int i = 0; i < MAX_CONN; ++i) {
-		if (connData[i].conn) {
-			espbuffsend(&connData[i], buf, length);
-		}
-	}
-	serledFlash(50); // short blink on serial LED
-}
 
 void ICACHE_FLASH_ATTR serbridgeInitPins() {
 	mcu_reset_pin = flashConfig.reset_pin;

serial/serbridge.h

@@ -11,26 +11,24 @@
 //Max send buffer len
 #define MAX_TXBUFFER 1024
 
-typedef struct serbridgeConnData serbridgeConnData;
-
 enum connModes {
 	cmInit = 0,        // initialization mode: nothing received yet
 	cmTransparent,     // transparent mode
 	cmAVR,             // Arduino/AVR programming mode
 	cmARM,             // ARM (LPC8xx) programming
 	cmEcho,            // simply echo characters (used for debugging latency)
-	cmCommand,         // AT command mode
   cmTelnet,          // use telnet escape sequences for programming mode
+  cmTcpClient,       // client connection (initiated via serial)
 };
 
-struct serbridgeConnData {
+typedef struct serbridgeConnData {
 	struct espconn *conn;
 	enum connModes conn_mode;   // connection mode
 	char           *txbuffer;   // buffer for the data to send
 	uint16         txbufferlen; // length of data in txbuffer
 	bool           readytosend; // true, if txbuffer can send by espconn_sent
   uint8_t        telnet_state;
-};
+} serbridgeConnData;
 
 void ICACHE_FLASH_ATTR serbridgeInit(int port);
 void ICACHE_FLASH_ATTR serbridgeInitPins(void);

serial/tcpclient.c

@@ -0,0 +1,272 @@
+// Copyright 2015 by Thorsten von Eicken, see LICENSE.txt
+
+#include <esp8266.h>
+#include "config.h"
+#include "uart.h"
+#include "serled.h"
+#include "tcpclient.h"
+
+// max number of channels the client can open
+#define MAX_CHAN 8
+// size of tx buffer
+#define MAX_TXBUF 1024
+
+enum TcpState {
+	TCP_idle,    // unused connection
+	TCP_dns,     // doing gethostbyname
+	TCP_conn,    // connecting to remote server
+	TCP_data,    // connected
+};
+
+// Connections
+typedef struct {
+	struct espconn *conn; // esp connection structure
+	esp_tcp *tcp;         // esp TCP parameters
+	char *txBuf;          // buffer to accumulate into
+	char *txBufSent;      // buffer held by espconn
+	uint8_t txBufLen;     // number of chars in txbuf
+	enum TcpState state;
+} TcpConn;
+
+#define MAX_CONN (8)
+static TcpConn tcpConn[MAX_CONN];
+
+// Free a connection dynamically.
+static void ICACHE_FLASH_ATTR
+tcpConnFree(TcpConn* tci) {
+	if (tci->conn != NULL) os_free(tci->conn);
+	if (tci->tcp != NULL) os_free(tci->tcp);
+	if (tci->txBuf != NULL) os_free(tci->txBuf);
+	if (tci->txBufSent != NULL) os_free(tci->txBufSent);
+	memset(tci, 0, sizeof(TcpConn));
+}
+
+// DNS name resolution callback
+static void ICACHE_FLASH_ATTR
+tcpClientHostnameCb(const char *name, ip_addr_t *ipaddr, void *arg) {
+	struct espconn *conn = arg;
+	TcpConn *tci = conn->reverse;
+	os_printf("TCP dns CB (%p %p)\n", arg, tci);
+	if (ipaddr == NULL) {
+		os_printf("TCP %s not found\n", name);
+	} else {
+		os_printf("TCP %s -> %d.%d.%d.%d\n", name, IP2STR(ipaddr));
+		tci->tcp->remote_ip[0] = ip4_addr1(ipaddr);
+		tci->tcp->remote_ip[1] = ip4_addr2(ipaddr);
+		tci->tcp->remote_ip[2] = ip4_addr3(ipaddr);
+		tci->tcp->remote_ip[3] = ip4_addr4(ipaddr);
+		os_printf("TCP connect %d.%d.%d.%d (%p)\n", IP2STR(tci->tcp->remote_ip), tci);
+		if (espconn_connect(tci->conn) == ESPCONN_OK) {
+			tci->state = TCP_conn;
+			return;
+		}
+		os_printf("TCP connect failure\n");
+	}
+	// oops
+	tcpConnFree(tci);
+}
+
+// Send the next buffer (assumes that the connection is in a state that allows it)
+static void tcpDoSend(TcpConn *tci) {
+	sint8 err = espconn_sent(tci->conn, (uint8*)tci->txBuf, tci->txBufLen);
+	if (err == ESPCONN_OK) {
+		// send successful
+		os_printf("TCP sent (%p %p)\n", tci->conn, tci);
+		tci->txBufSent = tci->txBuf;
+		tci->txBuf = NULL;
+		tci->txBufLen = 0;
+	} else {
+		// send error, leave as-is and try again later...
+		os_printf("TCP send err (%p %p) %d\n", tci->conn, tci, err);
+	}
+}
+
+// Connected callback
+static void ICACHE_FLASH_ATTR tcpConnectCb(void *arg) {
+	struct espconn *conn = arg;
+	TcpConn *tci = conn->reverse;
+	os_printf("TCP connect CB (%p %p)\n", arg, tci);
+	tci->state = TCP_data;
+	// send any buffered data
+	if (tci->txBuf != NULL && tci->txBufLen > 0) tcpDoSend(tci);
+}
+
+// Sent callback
+static void ICACHE_FLASH_ATTR tcpSentCb(void *arg) {
+	struct espconn *conn = arg;
+	TcpConn *tci = conn->reverse;
+	os_printf("TCP sent CB (%p %p)\n", arg, tci);
+	if (tci->txBufSent != NULL) os_free(tci->txBufSent);
+	tci->txBufSent = NULL;
+
+	if (tci->txBuf != NULL && tci->txBufLen == MAX_TXBUF) {
+		// next buffer is full, send it now
+		tcpDoSend(tci);
+	}
+}
+
+// Recv callback
+static void ICACHE_FLASH_ATTR tcpRecvCb(void *arg, char *data, uint16_t len) {
+	struct espconn *conn = arg;
+	TcpConn *tci = conn->reverse;
+	os_printf("TCP recv CB (%p %p)\n", arg, tci);
+	if (tci->state == TCP_data) {
+		uart0_tx_buffer(data, len);
+	}
+	serledFlash(50); // short blink on serial LED
+}
+
+// Disconnect callback
+static void ICACHE_FLASH_ATTR tcpDisconCb(void *arg) {
+	struct espconn *conn = arg;
+	TcpConn *tci = conn->reverse;
+	os_printf("TCP disconnect CB (%p %p)\n", arg, tci);
+	tcpConnFree(tci);
+}
+
+// Connection reset callback
+static void ICACHE_FLASH_ATTR tcpResetCb(void *arg, sint8 err) {
+	struct espconn *conn = arg;
+	TcpConn *tci = conn->reverse;
+	os_printf("TCP reset CB (%p %p) err=%d\n", arg, tci, err);
+	tcpConnFree(tci);
+}
+
+// Allocate a new connection dynamically and return it. Returns NULL if no
+// connection could be allocated.
+static TcpConn* ICACHE_FLASH_ATTR
+tcpConnAlloc(void) {
+	int i;
+	for (i=0; i<MAX_CONN; i++) {
+		if (tcpConn[i].state == TCP_idle && tcpConn[i].conn == NULL) break;
+	}
+	if (i == MAX_CONN) return NULL;
+
+	// found an empty slot, malloc and return espconn struct
+	TcpConn *tci = tcpConn+i;
+	tci->conn = os_malloc(sizeof(struct espconn));
+	if (tci->conn == NULL) goto fail;
+	memset(tci->conn, 0, sizeof(struct espconn));
+	// malloc esp_tcp struct
+	tci->tcp = os_malloc(sizeof(esp_tcp));
+	if (tci->tcp == NULL) goto fail;
+	memset(tci->tcp, 0, sizeof(esp_tcp));
+
+	// common init
+	tci->state = TCP_dns;
+	tci->conn->type = ESPCONN_TCP;
+	tci->conn->state = ESPCONN_NONE;
+	tci->conn->proto.tcp = tci->tcp;
+	tci->tcp->remote_port = 80;
+	tci->tcp->remote_ip[0] = 173;
+	espconn_regist_connectcb(tci->conn, tcpConnectCb);
+	espconn_regist_reconcb(tci->conn, tcpResetCb);
+	espconn_regist_sentcb(tci->conn, tcpSentCb);
+	espconn_regist_recvcb(tci->conn, tcpRecvCb);
+	espconn_regist_disconcb(tci->conn, tcpDisconCb);
+	tci->conn->reverse = tci;
+
+	return tci;
+
+fail:
+	tcpConnFree(tci);
+	return NULL;
+}
+
+static TcpConn *tcConn[MAX_CHAN];
+
+// Perform a TCP command: parse the command and do the right thing.
+// Returns true on success.
+bool ICACHE_FLASH_ATTR
+tcpClientCommand(char cmd, char *cmdBuf) {
+	uint8_t tcChan;
+	TcpConn *tci;
+
+	switch (cmd) {
+	//== TCP Connect command
+	case 'T':
+		if (*cmdBuf < '1' || *cmdBuf > ('0'+MAX_CHAN)) break;
+		tcChan = *cmdBuf++ - '1';
+		char *hostname = cmdBuf;
+		char *port = hostname;
+		while (*port != 0 && *port != ':') port++;
+		if (*port != ':') break;
+		*port = 0;
+		port++;
+		int portInt = atoi(port);
+		if (portInt < 1 || portInt > 65535) break;
+
+		// allocate a connection
+		tci = tcpConnAlloc();
+		if (tci == NULL) break;
+		tci->state = TCP_dns;
+		tci->tcp->remote_port = portInt;
+
+		// start the DNS resolution
+		os_printf("TCP %p resolving %s (conn=%p)\n", tci, hostname, tci->conn);
+		ip_addr_t ip;
+		err_t err = espconn_gethostbyname(tci->conn, hostname, &ip, tcpClientHostnameCb);
+		if (err == ESPCONN_OK) {
+			// dns cache hit, got the IP address, fake the callback (sigh)
+			os_printf("TCP DNS hit\n");
+			tcpClientHostnameCb(hostname, &ip, tci->conn);
+		} else if (err != ESPCONN_INPROGRESS) {
+			tcpConnFree(tci);
+			break;
+		}
+
+		tcConn[tcChan] = tci;
+		return true;
+
+	//== TCP Close/disconnect command
+	case 'C':
+		if (*cmdBuf < '1' || *cmdBuf > ('0'+MAX_CHAN)) break;
+		tcChan = *cmdBuf++ - '1';
+		tci = tcConn[tcChan];
+		if (tci->state > TCP_idle) {
+			tci->state = TCP_idle; // hackish...
+			espconn_disconnect(tci->conn);
+		}
+		break;
+
+	}
+	return false;
+}
+
+void ICACHE_FLASH_ATTR
+tcpClientSendChar(uint8_t chan, char c) {
+	TcpConn *tci = tcConn[chan];
+	if (tci->state == TCP_idle) return;
+
+	if (tci->txBuf != NULL) {
+		// we have a buffer
+		if (tci->txBufLen < MAX_TXBUF) {
+			// buffer has space, add char and return
+			tci->txBuf[tci->txBufLen++] = c;
+			return;
+		} else if (tci->txBufSent == NULL) {
+			// we don't have a send pending, send full buffer off
+			tcpDoSend(tci);
+			if (tci->txBuf != NULL) return; // something went wrong
+		} else {
+			// buffers all backed-up, drop char
+			return;
+		}
+	}
+	// we do not have a buffer (either didn't have one or sent it off)
+	// allocate one
+	tci->txBuf = os_malloc(MAX_TXBUF);
+	tci->txBufLen = 0;
+	if (tci->txBuf != NULL) {
+		tci->txBuf[tci->txBufLen++] = c;
+	}
+}
+
+void ICACHE_FLASH_ATTR
+tcpClientSendPush(uint8_t chan) {
+	TcpConn *tci = tcConn[chan];
+	if (tci->state == TCP_idle) return; // no active connection on this channel
+	if (tci->txBuf == NULL || tci->txBufLen == 0) return; // no chars accumulated to send
+	if (tci->txBufSent != NULL) return; // already got a send in progress
+	tcpDoSend(tci);
+}

serial/tcpclient.h

@@ -0,0 +1,8 @@
+#ifndef __TCP_CLIENT_H__
+#define __TCP_CLIENT_H__
+
+bool tcpClientCommand(char cmd, char *cmdBuf);
+void tcpClientSendChar(uint8_t chan, char c);
+void tcpClientSendPush(uint8_t chan);
+
+#endif /* __TCP_CLIENT_H__ */

user/cgiflash.c

@@ -160,6 +160,7 @@ int ICACHE_FLASH_ATTR cgiRebootFirmware(HttpdConnData *connData) {
 	int address = id == 1 ? 4*1024                   // either start after 4KB boot partition
 	    : 4*1024 + FIRMWARE_SIZE + 16*1024 + 4*1024; // 4KB boot, fw1, 16KB user param, 4KB reserved
 	uint32 buf[8];
+	os_printf("Checking %p\n", (void *)address);
 	spi_flash_read(address, buf, sizeof(buf));
 	char *err = check_header(buf);
 	if (err != NULL) {

user/status.c

@@ -5,8 +5,11 @@
 #include "serled.h"
 #include "cgiwifi.h"
 
+//===== "CONN" LED status indication
+
 static ETSTimer ledTimer;
 
+// Set the LED on or off, respecting the defined polarity
 static void ICACHE_FLASH_ATTR setLed(int on) {
   int8_t pin = flashConfig.conn_led_pin;
   if (pin < 0) return; // disabled
@@ -21,11 +24,12 @@ static void ICACHE_FLASH_ATTR setLed(int on) {
 static uint8_t ledState = 0;
 static uint8_t wifiState = 0;
 
+// Timer callback to update the LED
 static void ICACHE_FLASH_ATTR ledTimerCb(void *v) {
 	int time = 1000;
 
 	if (wifiState == wifiGotIP) {
-		// connected, all is good, solid light
+		// connected, all is good, solid light with a short dark blip every 3 seconds
 		ledState = 1-ledState;
 		time = ledState ? 2900 : 100;
 	} else if (wifiState == wifiIsConnected) {
@@ -33,7 +37,7 @@ static void ICACHE_FLASH_ATTR ledTimerCb(void *v) {
 		ledState = 1 - ledState;
 		time = 1000;
 	} else {
-		// idle
+		// not connected
 		switch (wifi_get_opmode()) {
 		case 1: // STA
 			ledState = 0;
@@ -53,7 +57,7 @@ static void ICACHE_FLASH_ATTR ledTimerCb(void *v) {
 	os_timer_arm(&ledTimer, time, 0);
 }
 
-// change the wifi state
+// change the wifi state indication
 void ICACHE_FLASH_ATTR statusWifiUpdate(uint8_t state) {
 	wifiState = state;
 	// schedule an update (don't want to run into concurrency issues)
@@ -62,6 +66,111 @@ void ICACHE_FLASH_ATTR statusWifiUpdate(uint8_t state) {
 	os_timer_arm(&ledTimer, 500, 0);
 }
 
+//===== RSSI Status update sent to GroveStreams
+
+#define RSSI_INTERVAL (60*1000)
+
+static ETSTimer rssiTimer;
+
+static uint8_t rssiSendState = 0;
+static sint8 rssiLast = 0; //last RSSI value
+
+static esp_tcp rssiTcp;
+static struct espconn rssiConn;
+
+#define GS_API_KEY "2eb868a8-224f-3faa-939d-c79bd605912a"
+#define GS_COMP_ID "esp-link"
+#define GS_STREAM  "rssi"
+
+// Connected callback
+static void ICACHE_FLASH_ATTR rssiConnectCb(void *arg) {
+	struct espconn *conn = (struct espconn *)arg;
+	os_printf("RSSI connect CB (%p %p)\n", arg, conn->reverse);
+
+	char buf[2000];
+
+	// http header
+	int hdrLen = os_sprintf(buf,
+			"PUT /api/feed?api_key=%s HTTP/1.0\r\n"
+			"Content-Type: application/json\r\n"
+			"Content-Length: XXXXX\r\n\r\n",
+			GS_API_KEY);
+
+	// http body
+	int dataLen = os_sprintf(buf+hdrLen,
+			"[{\"compId\":\"%s\", \"streamId\":\"%s\", \"data\":%d}]",
+			GS_COMP_ID, GS_STREAM, rssiLast);
+
+	// hackish way to fill in the content-length
+	os_sprintf(buf+hdrLen-9, "%5d", dataLen);
+	buf[hdrLen-4] = '\r';
+
+	// send it off
+	if (espconn_sent(conn, (uint8*)buf, hdrLen+dataLen) == ESPCONN_OK) {
+		os_printf("RSSI sent rssi=%d\n", rssiLast);
+		os_printf("RSSI sent <<%s>>\n", buf);
+	}
+}
+
+// Sent callback
+static void ICACHE_FLASH_ATTR rssiSentCb(void *arg) {
+	struct espconn *conn = (struct espconn *)arg;
+	os_printf("RSSI sent CB (%p %p)\n", arg, conn->reverse);
+}
+
+// Recv callback
+static void ICACHE_FLASH_ATTR rssiRecvCb(void *arg, char *data, uint16_t len) {
+	struct espconn *conn = (struct espconn *)arg;
+	os_printf("RSSI recv CB (%p %p)\n", arg, conn->reverse);
+	data[len] = 0; // hack!!!
+	os_printf("GOT %d: <<%s>>\n", len, data);
+
+	espconn_disconnect(conn);
+}
+
+// Disconnect callback
+static void ICACHE_FLASH_ATTR rssiDisconCb(void *arg) {
+	struct espconn *conn = (struct espconn *)arg;
+	os_printf("RSSI disconnect CB (%p %p)\n", arg, conn->reverse);
+	rssiSendState = 0;
+}
+
+// Connection reset callback
+static void ICACHE_FLASH_ATTR rssiResetCb(void *arg, sint8 err) {
+	struct espconn *conn = (struct espconn *)arg;
+	os_printf("RSSI reset CB (%p %p) err=%d\n", arg, conn->reverse, err);
+	rssiSendState = 0;
+}
+
+// Timer callback to send an RSSI update to a monitoring system
+static void ICACHE_FLASH_ATTR rssiTimerCb(void *v) {
+	sint8 rssi = wifi_station_get_rssi();
+	if (rssi >= 0) return; // not connected or other error
+	rssiLast = rssi;
+	if (rssiSendState > 0) return; // not done with previous rssi report
+
+	rssiConn.type = ESPCONN_TCP;
+	rssiConn.state = ESPCONN_NONE;
+	rssiConn.proto.tcp = &rssiTcp;
+	rssiTcp.remote_port = 80;
+	rssiTcp.remote_ip[0] = 173;
+  rssiTcp.remote_ip[1] = 236;
+  rssiTcp.remote_ip[2] = 12;
+  rssiTcp.remote_ip[3] = 163;
+  espconn_regist_connectcb(&rssiConn, rssiConnectCb);
+	espconn_regist_reconcb(&rssiConn, rssiResetCb);
+	espconn_regist_sentcb(&rssiConn, rssiSentCb);
+	espconn_regist_recvcb(&rssiConn, rssiRecvCb);
+	espconn_regist_disconcb(&rssiConn, rssiDisconCb);
+	rssiConn.reverse = (void *)0xdeadf00d;
+	os_printf("RSSI connect (%p)\n", &rssiConn);
+	if (espconn_connect(&rssiConn) == ESPCONN_OK) {
+		rssiSendState++;
+	}
+}
+
+//===== Init status stuff
+
 void ICACHE_FLASH_ATTR statusInit(void) {
 	if (flashConfig.conn_led_pin >= 0) {
 		makeGpio(flashConfig.conn_led_pin);
@@ -72,6 +181,10 @@ void ICACHE_FLASH_ATTR statusInit(void) {
 	os_timer_disarm(&ledTimer);
 	os_timer_setfn(&ledTimer, ledTimerCb, NULL);
 	os_timer_arm(&ledTimer, 2000, 0);
+
+	os_timer_disarm(&rssiTimer);
+	os_timer_setfn(&rssiTimer, rssiTimerCb, NULL);
+	os_timer_arm(&rssiTimer, RSSI_INTERVAL, 1); // recurring timer
 }