src/BlinkenProto.c (c9469b6) - BlinkenLib · BlinkenArea

BlinkenProto.c

/* BlinkenLib
   Copyright 2004-2014 Stefan Schuermans <stefan@schuermans.info>
   Copyleft GNU public license - http://www.gnu.org/copyleft/gpl.html
   a blinkenarea.org project */

#include <string.h>
#ifdef WIN32
#include <winsock2.h>
#include <windows.h>
typedef WORD uint16_t;
typedef DWORD uint32_t;
#else
#include <stdint.h>
#include <netinet/in.h>
#endif

#include <BlinkenLib/BlinkenProto.h>

#include "BlinkenProtoIntern.h"

int BlinkenProtoMakePacket(etBlinkenProto proto, etBlinkenPacket packet,
                           char *pData, int maxLength)
// returns length or -1 on error
{
  uint32_t magic;
  char *body;
  int len;

magic = 0;
  len = -1;

// info packet processing: body identical for all protocols
  switch (packet) {
    case BlinkenPacketStreamEnd:
      body = "END\0\0\0\0\0";
      len = 8;
      break;
    case BlinkenPacketNone:
    case BlinkenPacketFrame:
    case BlinkenPacketRequest:
    case BlinkenPacketEndRequest:
      // keep compiler happy
      break;
  }

switch (proto) {
  case BlinkenProtoNone:
    break;
  case BlinkenProtoBlp:
    switch (packet) {
      case BlinkenPacketFrame:
        magic = BlinkenProtoBlpMagic;
        body = "\0\0\0\0\0\0\0\0"; // size 0x0
        len = 8;
        break;
      case BlinkenPacketRequest:
        magic = BlinkenProtoBlpReqMagic;
        body = "REFRESH";
        len = 7;
        break;
      case BlinkenPacketEndRequest:
        magic = BlinkenProtoBlpReqMagic;
        body = "CLOSE";
        len = 5;
        break;
      default: // might be info packet, set only magic
        magic = BlinkenProtoBlpInfoMagic;
        break;
    }
    break;
  case BlinkenProtoEblp:
    switch (packet) {
      case BlinkenPacketFrame:
        magic = BlinkenProtoEblpMagic;
        body = "\0\0\0\0\0\0\0\0"; // size 0x0
        len = 8;
        break;
      case BlinkenPacketRequest:
        magic = BlinkenProtoBlpReqMagic;
        body = "REFRESH256";
        len = 10;
        break;
      case BlinkenPacketEndRequest:
        magic = BlinkenProtoBlpReqMagic;
        body = "CLOSE256";
        len = 8;
        break;
      default: // might be info packet, set only magic
        magic = BlinkenProtoEblpInfoMagic;
        break;
    }
    break;
  case BlinkenProtoMcuf:
    switch (packet) {
      case BlinkenPacketFrame:
        magic = BlinkenProtoMcufMagic;
        body = "\0\0\0\0\0\0\0\0"; // size 0x0
        len = 8;
        break;
      case BlinkenPacketRequest:
        magic = BlinkenProtoMcufReqMagic;
        body = "\0\0\0\0\0\0\0\0";
        len = 8;
        break;
      case BlinkenPacketEndRequest:
        magic = BlinkenProtoMcufEndReqMagic;
        body = "\0\0\0\0\0\0\0\0";
        len = 8;
        break;
      default: // might be info packet, set only magic
        magic = BlinkenProtoMcufInfoMagic;
        break;
    }
    break;
  }

// magic not set or body not set -> error
  if (magic == 0 || len < 0)
    return -1;

// fill buffer
  if (maxLength < (int)sizeof(magic))
    return -1;
  *(uint32_t *)pData = htonl(magic);
  if (maxLength < (int)sizeof(magic) + len) {
    memcpy(pData + sizeof(magic), body, maxLength - sizeof(magic));
    return -1;
  }
  memcpy(pData + sizeof(magic), body, len);
  return sizeof(magic) + len;
}

void BlinkenProtoDetectPacket(const char *pData, int length,
                              etBlinkenProto * pProto,
                              etBlinkenPacket * pPacket)
// returns protocol in *pProto if pProto not NULL
// returns packet type in *pPacket if pPacket not NULL
{
  uint32_t magic;
  int info;

// get magic
  if (length < (int)sizeof(magic)) {
    if (pProto)
      *pProto = BlinkenProtoNone;
    if (pPacket)
      *pPacket = BlinkenPacketNone;
    return;
  }
  magic = ntohl(*(uint32_t *)pData);

info = 0;
  switch (magic) {
  case BlinkenProtoBlpMagic:
    if (length >= (int)sizeof(stBlinkenProtoBlpHdr)) {
      if (pProto)
        *pProto = BlinkenProtoBlp;
      if (pPacket)
        *pPacket = BlinkenPacketFrame;
      return;
    }
    break;
  case BlinkenProtoBlpReqMagic:
    if (length >= (int)sizeof(magic) + 10 && !memcmp(pData + sizeof(magic), "REFRESH256", 10)) {
      if (pProto)
        *pProto = BlinkenProtoEblp;
      if (pPacket)
        *pPacket = BlinkenPacketRequest;
      return;
    }
    if (length >= (int)sizeof(magic) + 8 && !memcmp(pData + sizeof(magic), "CLOSE256", 8)) {
      if (pProto)
        *pProto = BlinkenProtoEblp;
      if (pPacket)
        *pPacket = BlinkenPacketEndRequest;
      return;
    }
    if (length >= (int)sizeof(magic) + 7 && !memcmp(pData + sizeof(magic), "REFRESH", 7)) {
      if (pProto)
        *pProto = BlinkenProtoBlp;
      if (pPacket)
        *pPacket = BlinkenPacketRequest;
      return;
    }
    if (length >= (int)sizeof(magic) + 5 && !memcmp(pData + sizeof(magic), "CLOSE", 5)) {
      if (pProto)
        *pProto = BlinkenProtoBlp;
      if (pPacket)
        *pPacket = BlinkenPacketEndRequest;
      return;
    }
    break;
  case BlinkenProtoBlpInfoMagic:
    if (length >= (int)sizeof(magic) + 8) {
      if (pProto)
        *pProto = BlinkenProtoBlp;
      info = 1; // further processing of info packet below
    }
    break;
  case BlinkenProtoEblpMagic:
    if (length >= (int)sizeof(stBlinkenProtoEblpHdr)) {
      if (pProto)
        *pProto = BlinkenProtoEblp;
      if (pPacket)
        *pPacket = BlinkenPacketFrame;
      return;
    }
    break;
  case BlinkenProtoEblpInfoMagic:
    if (length >= (int)sizeof(magic) + 8) {
      if (pProto)
        *pProto = BlinkenProtoEblp;
      info = 1; // further processing of info packet below
    }
    break;
  case BlinkenProtoMcufMagic:
    if (length >= (int)sizeof(stBlinkenProtoMcufHdr)) {
      if (pProto)
        *pProto = BlinkenProtoMcuf;
      if (pPacket)
        *pPacket = BlinkenPacketFrame;
      return;
    }
    break;
  case BlinkenProtoMcufReqMagic:
    if (pProto)
      *pProto = BlinkenProtoMcuf;
    if (pPacket)
      *pPacket = BlinkenPacketRequest;
    return;
  case BlinkenProtoMcufEndReqMagic:
    if (pProto)
      *pProto = BlinkenProtoMcuf;
    if (pPacket)
      *pPacket = BlinkenPacketEndRequest;
    return;
  case BlinkenProtoMcufInfoMagic:
    if (length >= (int)sizeof(magic) + 8) {
      if (pProto)
        *pProto = BlinkenProtoMcuf;
      info = 1; // further processing of info packet below
    }
    break;
  }

// info packet processing: body identical for all protocols
  if (info) {
    if (!memcmp(pData + sizeof(magic), "END\0\0\0\0\0", 8)) {
      if (pPacket)
        *pPacket = BlinkenPacketStreamEnd;
      return;
    }
    // unknown info packet
    if (pPacket)
      *pPacket = BlinkenPacketNone;
    return;
  }

// unknown packet
  if (pProto)
    *pProto = BlinkenProtoNone;
  if (pPacket)
    *pPacket = BlinkenPacketNone;
}

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