esp-open-rtos/extras/paho/MQTTPacket.c
Yudi Ludkevich 4d14a874af MQTT client api and example
This code based on ESP8266 port of the embedded C client in Eclipse Paho project
(http://www.eclipse.org/paho/) and it port for espressif
ESP8266_RTOS_SDK by baoshi (https://github.com/baoshi/ESP-RTOS-Paho.git)
2016-02-19 23:00:13 +03:00

410 lines
10 KiB
C

/*******************************************************************************
* Copyright (c) 2014 IBM Corp.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* and Eclipse Distribution License v1.0 which accompany this distribution.
*
* The Eclipse Public License is available at
* http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Ian Craggs - initial API and implementation and/or initial documentation
* Sergio R. Caprile - non-blocking packet read functions for stream transport
*******************************************************************************/
#include <espressif/esp_common.h>
#include "StackTrace.h"
#include "MQTTPacket.h"
#include <c_types.h>
#include <string.h>
/**
* Encodes the message length according to the MQTT algorithm
* @param buf the buffer into which the encoded data is written
* @param length the length to be encoded
* @return the number of bytes written to buffer
*/
int ICACHE_FLASH_ATTR MQTTPacket_encode(unsigned char* buf, int length)
{
int rc = 0;
FUNC_ENTRY;
do
{
char d = length % 128;
length /= 128;
/* if there are more digits to encode, set the top bit of this digit */
if (length > 0)
d |= 0x80;
buf[rc++] = d;
} while (length > 0);
FUNC_EXIT_RC(rc);
return rc;
}
/**
* Decodes the message length according to the MQTT algorithm
* @param getcharfn pointer to function to read the next character from the data source
* @param value the decoded length returned
* @return the number of bytes read from the socket
*/
int ICACHE_FLASH_ATTR MQTTPacket_decode(int (*getcharfn)(unsigned char*, int), int* value)
{
unsigned char c;
int multiplier = 1;
int len = 0;
#define MAX_NO_OF_REMAINING_LENGTH_BYTES 4
FUNC_ENTRY;
*value = 0;
do
{
int rc = MQTTPACKET_READ_ERROR;
if (++len > MAX_NO_OF_REMAINING_LENGTH_BYTES)
{
rc = MQTTPACKET_READ_ERROR; /* bad data */
goto exit;
}
rc = (*getcharfn)(&c, 1);
if (rc != 1)
goto exit;
*value += (c & 127) * multiplier;
multiplier *= 128;
} while ((c & 128) != 0);
exit:
FUNC_EXIT_RC(len);
return len;
}
int ICACHE_FLASH_ATTR MQTTPacket_len(int rem_len)
{
rem_len += 1; /* header byte */
/* now remaining_length field */
if (rem_len < 128)
rem_len += 1;
else if (rem_len < 16384)
rem_len += 2;
else if (rem_len < 2097151)
rem_len += 3;
else
rem_len += 4;
return rem_len;
}
static unsigned char* bufptr;
int ICACHE_FLASH_ATTR bufchar(unsigned char* c, int count)
{
int i;
for (i = 0; i < count; ++i)
*c = *bufptr++;
return count;
}
int ICACHE_FLASH_ATTR MQTTPacket_decodeBuf(unsigned char* buf, int* value)
{
bufptr = buf;
return MQTTPacket_decode(bufchar, value);
}
/**
* Calculates an integer from two bytes read from the input buffer
* @param pptr pointer to the input buffer - incremented by the number of bytes used & returned
* @return the integer value calculated
*/
int ICACHE_FLASH_ATTR readInt(unsigned char** pptr)
{
unsigned char* ptr = *pptr;
int len = 256*(*ptr) + (*(ptr+1));
*pptr += 2;
return len;
}
/**
* Reads one character from the input buffer.
* @param pptr pointer to the input buffer - incremented by the number of bytes used & returned
* @return the character read
*/
char ICACHE_FLASH_ATTR readChar(unsigned char** pptr)
{
char c = **pptr;
(*pptr)++;
return c;
}
/**
* Writes one character to an output buffer.
* @param pptr pointer to the output buffer - incremented by the number of bytes used & returned
* @param c the character to write
*/
void ICACHE_FLASH_ATTR writeChar(unsigned char** pptr, char c)
{
**pptr = c;
(*pptr)++;
}
/**
* Writes an integer as 2 bytes to an output buffer.
* @param pptr pointer to the output buffer - incremented by the number of bytes used & returned
* @param anInt the integer to write
*/
void ICACHE_FLASH_ATTR writeInt(unsigned char** pptr, int anInt)
{
**pptr = (unsigned char)(anInt / 256);
(*pptr)++;
**pptr = (unsigned char)(anInt % 256);
(*pptr)++;
}
/**
* Writes a "UTF" string to an output buffer. Converts C string to length-delimited.
* @param pptr pointer to the output buffer - incremented by the number of bytes used & returned
* @param string the C string to write
*/
void ICACHE_FLASH_ATTR writeCString(unsigned char** pptr, const char* string)
{
int len = strlen(string);
writeInt(pptr, len);
memcpy(*pptr, string, len);
*pptr += len;
}
int ICACHE_FLASH_ATTR getLenStringLen(char* ptr)
{
int len = 256*((unsigned char)(*ptr)) + (unsigned char)(*(ptr+1));
return len;
}
void ICACHE_FLASH_ATTR writeMQTTString(unsigned char** pptr, MQTTString mqttstring)
{
if (mqttstring.lenstring.len > 0)
{
writeInt(pptr, mqttstring.lenstring.len);
memcpy(*pptr, mqttstring.lenstring.data, mqttstring.lenstring.len);
*pptr += mqttstring.lenstring.len;
}
else if (mqttstring.cstring)
writeCString(pptr, mqttstring.cstring);
else
writeInt(pptr, 0);
}
/**
* @param mqttstring the MQTTString structure into which the data is to be read
* @param pptr pointer to the output buffer - incremented by the number of bytes used & returned
* @param enddata pointer to the end of the data: do not read beyond
* @return 1 if successful, 0 if not
*/
int ICACHE_FLASH_ATTR readMQTTLenString(MQTTString* mqttstring, unsigned char** pptr, unsigned char* enddata)
{
int rc = 0;
FUNC_ENTRY;
/* the first two bytes are the length of the string */
if (enddata - (*pptr) > 1) /* enough length to read the integer? */
{
mqttstring->lenstring.len = readInt(pptr); /* increments pptr to point past length */
if (&(*pptr)[mqttstring->lenstring.len] <= enddata)
{
mqttstring->lenstring.data = (char*)*pptr;
*pptr += mqttstring->lenstring.len;
rc = 1;
}
}
mqttstring->cstring = NULL;
FUNC_EXIT_RC(rc);
return rc;
}
/**
* Return the length of the MQTTstring - C string if there is one, otherwise the length delimited string
* @param mqttstring the string to return the length of
* @return the length of the string
*/
int ICACHE_FLASH_ATTR MQTTstrlen(MQTTString mqttstring)
{
int rc = 0;
if (mqttstring.cstring)
rc = strlen(mqttstring.cstring);
else
rc = mqttstring.lenstring.len;
return rc;
}
/**
* Compares an MQTTString to a C string
* @param a the MQTTString to compare
* @param bptr the C string to compare
* @return boolean - equal or not
*/
int ICACHE_FLASH_ATTR MQTTPacket_equals(MQTTString* a, char* bptr)
{
int alen = 0,
blen = 0;
char *aptr;
if (a->cstring)
{
aptr = a->cstring;
alen = strlen(a->cstring);
}
else
{
aptr = a->lenstring.data;
alen = a->lenstring.len;
}
blen = strlen(bptr);
return (alen == blen) && (strncmp(aptr, bptr, alen) == 0);
}
/**
* Helper function to read packet data from some source into a buffer
* @param buf the buffer into which the packet will be serialized
* @param buflen the length in bytes of the supplied buffer
* @param getfn pointer to a function which will read any number of bytes from the needed source
* @return integer MQTT packet type, or -1 on error
* @note the whole message must fit into the caller's buffer
*/
int ICACHE_FLASH_ATTR MQTTPacket_read(unsigned char* buf, int buflen, int (*getfn)(unsigned char*, int))
{
int rc = -1;
MQTTHeader header = {0};
int len = 0;
int rem_len = 0;
/* 1. read the header byte. This has the packet type in it */
if ((*getfn)(buf, 1) != 1)
goto exit;
len = 1;
/* 2. read the remaining length. This is variable in itself */
MQTTPacket_decode(getfn, &rem_len);
len += MQTTPacket_encode(buf + 1, rem_len); /* put the original remaining length back into the buffer */
/* 3. read the rest of the buffer using a callback to supply the rest of the data */
if((rem_len + len) > buflen)
goto exit;
if ((*getfn)(buf + len, rem_len) != rem_len)
goto exit;
header.byte = buf[0];
rc = header.bits.type;
exit:
return rc;
}
/**
* Decodes the message length according to the MQTT algorithm, non-blocking
* @param trp pointer to a transport structure holding what is needed to solve getting data from it
* @param value the decoded length returned
* @return integer the number of bytes read from the socket, 0 for call again, or -1 on error
*/
static int ICACHE_FLASH_ATTR MQTTPacket_decodenb(MQTTTransport *trp)
{
unsigned char c;
int rc = MQTTPACKET_READ_ERROR;
FUNC_ENTRY;
if(trp->len == 0){ /* initialize on first call */
trp->multiplier = 1;
trp->rem_len = 0;
}
do {
int frc;
if (++(trp->len) > MAX_NO_OF_REMAINING_LENGTH_BYTES)
goto exit;
if ((frc=(*trp->getfn)(trp->sck, &c, 1)) == -1)
goto exit;
if (frc == 0){
rc = 0;
goto exit;
}
trp->rem_len += (c & 127) * trp->multiplier;
trp->multiplier *= 128;
} while ((c & 128) != 0);
rc = trp->len;
exit:
FUNC_EXIT_RC(rc);
return rc;
}
/**
* Helper function to read packet data from some source into a buffer, non-blocking
* @param buf the buffer into which the packet will be serialized
* @param buflen the length in bytes of the supplied buffer
* @param trp pointer to a transport structure holding what is needed to solve getting data from it
* @return integer MQTT packet type, 0 for call again, or -1 on error
* @note the whole message must fit into the caller's buffer
*/
int ICACHE_FLASH_ATTR MQTTPacket_readnb(unsigned char* buf, int buflen, MQTTTransport *trp)
{
int rc = -1, frc;
MQTTHeader header = {0};
switch(trp->state){
default:
trp->state = 0;
/*FALLTHROUGH*/
case 0:
/* read the header byte. This has the packet type in it */
if ((frc=(*trp->getfn)(trp->sck, buf, 1)) == -1)
goto exit;
if (frc == 0)
return 0;
trp->len = 0;
++trp->state;
/*FALLTHROUGH*/
/* read the remaining length. This is variable in itself */
case 1:
if((frc=MQTTPacket_decodenb(trp)) == MQTTPACKET_READ_ERROR)
goto exit;
if(frc == 0)
return 0;
trp->len = 1 + MQTTPacket_encode(buf + 1, trp->rem_len); /* put the original remaining length back into the buffer */
if((trp->rem_len + trp->len) > buflen)
goto exit;
++trp->state;
/*FALLTHROUGH*/
case 2:
/* read the rest of the buffer using a callback to supply the rest of the data */
if ((frc=(*trp->getfn)(trp->sck, buf + trp->len, trp->rem_len)) == -1)
goto exit;
if (frc == 0)
return 0;
trp->rem_len -= frc;
trp->len += frc;
if(trp->rem_len)
return 0;
header.byte = buf[0];
rc = header.bits.type;
break;
}
exit:
trp->state = 0;
return rc;
}