ldp_nortel.c

实现了MPLS中的标签分发协议（LDP 3036 )的基本功能

  encodedSize = Mpls_encodeLdpTlv(&(chp->baseTlv), tempBuf, MPLS_TLVFIXLEN);
  if (encodedSize < 0) {
    return MPLS_ENC_TLVERROR;
  }

  chpPtr = (u_char *) chp;
  tempBuf += encodedSize;
  chpPtr += encodedSize;

  /* 
   *  encode for hold time + T +  R + res 
   */
  chp->flags.flags.res = 0;
  chp->flags.mark = htons(chp->flags.mark);
  chp->holdTime = htons(chp->holdTime);

  MEM_COPY(tempBuf, chpPtr, MPLS_CHPFIXLEN);

  return (MPLS_TLVFIXLEN + MPLS_CHPFIXLEN);

}                               /* End: Mpls_encodeLdpChp */

/* 
 * decode
 */
int Mpls_decodeLdpChp(mplsLdpChpTlv_t * chp, u_char * buff, int bufSize)
{
  u_char *chpPtr;

  if (MPLS_CHPFIXLEN > bufSize) {
    /* not enough data for Chp */
    PRINT_ERR("failed decoding hello Chp\n");
    return MPLS_DEC_BUFFTOOSMALL;
  }

  chpPtr = (u_char *) chp;
  chpPtr += MPLS_TLVFIXLEN;     /* we want to point to the flags since the
                                   tlv was decoded before we reach here */

  /*
   *  decode for the rest of the Chp
   */
  MEM_COPY(chpPtr, buff, MPLS_CHPFIXLEN);

  chp->holdTime = ntohs(chp->holdTime);
  chp->flags.mark = ntohs(chp->flags.mark);

  return MPLS_CHPFIXLEN;

}                               /* End: Mpls_decodeLdpChp */

/* 
 * Encode for Configuration Sequence Number TLV
 */

/*
 *  encode
 */
int Mpls_encodeLdpCsn(mplsLdpCsnTlv_t * csn, u_char * buff, int bufSize)
{
  int encodedSize = 0;
  u_char *tempBuf = buff;       /* no change for the buff ptr */

  if (MPLS_CSNFIXLEN + MPLS_TLVFIXLEN > bufSize) {
    /* not enough room */
    return MPLS_ENC_BUFFTOOSMALL;
  }

  /*
   *  encode for tlv
   */
  encodedSize = Mpls_encodeLdpTlv(&(csn->baseTlv), tempBuf, bufSize);
  if (encodedSize < 0) {
    PRINT_ERR("failed encoding the tlv in hello Csn\n");
    return MPLS_ENC_TLVERROR;
  }
  tempBuf += encodedSize;

  csn->seqNumber = htonl(csn->seqNumber);

  MEM_COPY(tempBuf, (u_char *) & (csn->seqNumber), MPLS_CSNFIXLEN);

  return (MPLS_CSNFIXLEN + MPLS_TLVFIXLEN);

}                               /* End: Mpls_encodeLdpCsn */

/* 
 * decode
 */
int Mpls_decodeLdpCsn(mplsLdpCsnTlv_t * csn, u_char * buff, int bufSize)
{
  u_char *tempBuf = buff;       /* no change for the buff ptr */

  if (MPLS_CSNFIXLEN > bufSize) {
    /* not enough data for csn data */
    PRINT_ERR("failed decoding hello Csn\n");
    return MPLS_DEC_BUFFTOOSMALL;
  }

  /*
   *  decode for the rest of the Csn 
   */
  MEM_COPY(&(csn->seqNumber), tempBuf, MPLS_CSNFIXLEN);

  csn->seqNumber = ntohl(csn->seqNumber);

  return MPLS_CSNFIXLEN;

}                               /* End: Mpls_decodeLdpCsn */

/* 
 * Encode for Transport Address TLV 
 */

/*
 *  encode
 */
int Mpls_encodeLdpTrAdr(mplsLdpTrAdrTlv_t * trAdr, u_char * buff, int bufSize)
{
  int encodedSize = 0;
  u_char *tempBuf = buff;       /* no change for the buff ptr */

  if (MPLS_TRADRFIXLEN + MPLS_TLVFIXLEN > bufSize) {
    /* not enough room */
    return MPLS_ENC_BUFFTOOSMALL;
  }

  /*
   *  encode for tlv
   */
  encodedSize = Mpls_encodeLdpTlv(&(trAdr->baseTlv), tempBuf, bufSize);
  if (encodedSize < 0) {
    PRINT_ERR("failed encoding the tlv in hello TrAdr\n");
    return MPLS_ENC_TLVERROR;
  }
  tempBuf += encodedSize;

  trAdr->address = htonl(trAdr->address);

  MEM_COPY(tempBuf, (u_char *) & (trAdr->address), MPLS_TRADRFIXLEN);

  return (MPLS_TRADRFIXLEN + MPLS_TLVFIXLEN);

}                               /* End: Mpls_encodeLdpTrAdr */

/* 
 * decode 
 */
int Mpls_decodeLdpTrAdr(mplsLdpTrAdrTlv_t * trAdr, u_char * buff, int bufSize)
{
  u_char *tempBuf = buff;       /* no change for the buff ptr */

  if (MPLS_TRADRFIXLEN > bufSize) {
    /* not enough data for csn data */
    PRINT_ERR("failed decoding hello TrAdr\n");
    return MPLS_DEC_BUFFTOOSMALL;
  }

  /*
   *  decode for the rest of the TrAdr 
   */
  MEM_COPY(&(trAdr->address), tempBuf, MPLS_TRADRFIXLEN);

  trAdr->address = ntohl(trAdr->address);

  return MPLS_TRADRFIXLEN;

}                               /* End: Mpls_decodeLdpTrAdr */

/* 
 * Encode for KeepAlive Message
 */

/*
 *  encode
 */
int Mpls_encodeLdpKeepAliveMsg
  (mplsLdpKeepAlMsg_t * keepAlive, u_char * buff, int bufSize) {
  mplsLdpKeepAlMsg_t keepAliveCopy;
  int encodedSize = 0;

  if (MPLS_MSGIDFIXLEN + MPLS_TLVFIXLEN > bufSize) {
    PRINT_ERR("failed to encode the keep alive msg: BUFFER TOO SMALL\n");
    return MPLS_ENC_BUFFTOOSMALL;
  }

  keepAliveCopy = *keepAlive;

  encodedSize = Mpls_encodeLdpBaseMsg(&(keepAliveCopy.baseMsg), buff, bufSize);
  if (encodedSize < 0) {
    return MPLS_ENC_BASEMSGERROR;
  }
  PRINT_OUT("Encode BaseMsg for keep alive on %d bytes\n", encodedSize);

  return (MPLS_MSGIDFIXLEN + MPLS_TLVFIXLEN);

}                               /* End: Mpls_encodeLdpKeepAliveMsg */

/*
 *  decode
 */
int Mpls_decodeLdpKeepAliveMsg
  (mplsLdpKeepAlMsg_t * keepAlive, u_char * buff, int bufSize) {
  int decodedSize = 0;

  memset(keepAlive, 0, MPLS_MSGIDFIXLEN + MPLS_TLVFIXLEN);
  decodedSize = Mpls_decodeLdpBaseMsg(&(keepAlive->baseMsg), buff, bufSize);
  if (decodedSize < 0) {
    return MPLS_DEC_BASEMSGERROR;
  }
  PRINT_OUT("Decode BaseMsg for keep alive on %d bytes\n", decodedSize);

  if (keepAlive->baseMsg.flags.flags.msgType != MPLS_KEEPAL_MSGTYPE) {
    PRINT_ERR("Not the right message type; expected keep alive and got %x\n",
      keepAlive->baseMsg.flags.flags.msgType);
    return MPLS_MSGTYPEERROR;
  }

  return (MPLS_MSGIDFIXLEN + MPLS_TLVFIXLEN);

}                               /* End: Mpls_decodeLdpKeepAliveMsg */

/* 
 * Encode for Address List TLV 
 */

/*
 *  encode
 */
int Mpls_encodeLdpAdrTlv(mplsLdpAdrTlv_t * adrList, u_char * buff, int bufSize)
{
  int i, numberAdr;
  int encodedSize = 0;
  u_char *tempBuf = buff;       /* no change for the buff ptr */
  u_short tempLength;           /* to store the tlv length for

                                   later use */

  if (MPLS_TLVFIXLEN + (int)(adrList->baseTlv.length) > bufSize) {
    /* not enough room */
    return MPLS_ENC_BUFFTOOSMALL;
  }

  tempLength = adrList->baseTlv.length;
  /*
   *  encode for tlv
   */
  encodedSize = Mpls_encodeLdpTlv(&(adrList->baseTlv), tempBuf, bufSize);
  if (encodedSize < 0) {
    PRINT_ERR("failed encoding the tlv in AdrList\n");
    return MPLS_ENC_TLVERROR;
  }

  tempBuf += encodedSize;

  adrList->addrFamily = htons(adrList->addrFamily);

  numberAdr = (tempLength - sizeof(u_short)) / sizeof(u_int);
  for (i = 0; i < numberAdr; i++) {
    adrList->address[i] = htonl(adrList->address[i]);
  }

  MEM_COPY(tempBuf, (u_char *) & adrList->addrFamily, sizeof(u_short));

  tempBuf += sizeof(u_short);

  MEM_COPY(tempBuf,
    (u_char *) & adrList->address, tempLength - sizeof(u_short));

  return (tempLength + MPLS_TLVFIXLEN);

}                               /* End: Mpls_encodeLdpAdrTlv */

/*
 *  decode
 *
 *  Note: the tlvLength is used to specify what is the length of the 
 *        encoding in the AdrTlv.
 */
int Mpls_decodeLdpAdrTlv
  (mplsLdpAdrTlv_t * adrList, u_char * buff, int bufSize, u_short tlvLength) {
  u_char *tempBuf = buff;       /* no change for the buff ptr */
  int i, numberAdr;

  if ((int)tlvLength > bufSize) {
    /* not enough data for Adr list tlv */
    PRINT_ERR("failed decoding AddrList tlv\n");
    return MPLS_DEC_BUFFTOOSMALL;
  }

  /*
   *  decode for the addressFamily and addresses of the address list
   */
  MEM_COPY((u_char *) & adrList->addrFamily, tempBuf, sizeof(u_short));
  tempBuf += sizeof(u_short);

  adrList->addrFamily = ntohs(adrList->addrFamily);

  MEM_COPY((u_char *) & adrList->address, tempBuf, tlvLength - sizeof(u_short));

  numberAdr = (tlvLength - sizeof(u_short)) / sizeof(u_int);
  for (i = 0; i < numberAdr; i++) {
    adrList->address[i] = ntohl(adrList->address[i]);
  }

  return tlvLength;

}                               /* End: Mpls_decodeLdpAdrTlv */

/* 
 * Encode for Address / Address Withdraw messages
 */

/*
 *  encode
 */
int Mpls_encodeLdpAdrMsg(mplsLdpAdrMsg_t * addrMsg, u_char * buff, int bufSize)
{
  mplsLdpAdrMsg_t addrMsgCopy;
  int encodedSize = 0;
  u_int totalSize = 0;
  u_char *tempBuf = buff;       /* no change for the buff ptr */

  /* check the length of the messageId + param */
  if ((int)(addrMsg->baseMsg.msgLength) + MPLS_TLVFIXLEN > bufSize) {
    PRINT_ERR("failed to encode the address msg: BUFFER TOO SMALL\n");
    return MPLS_ENC_BUFFTOOSMALL;
  }

  addrMsgCopy = *addrMsg;

  /*
   *  encode the base part of the pdu message
   */
  encodedSize = Mpls_encodeLdpBaseMsg(&(addrMsgCopy.baseMsg), tempBuf, bufSize);
  if (encodedSize < 0) {
    return MPLS_ENC_BASEMSGERROR;
  }
  PRINT_OUT("Encode BaseMsg for address on %d bytes\n", encodedSize);
  tempBuf += encodedSize;
  totalSize += encodedSize;

  /*
   *  encode the address list tlv if any
   */
  if (addrMsg->adrListTlvExists) {
    encodedSize = Mpls_encodeLdpAdrTlv(&(addrMsgCopy.addressList),
      tempBuf, bufSize - totalSize);
    if (encodedSize < 0) {
      return MPLS_ENC_ADRLISTERROR;
    }
    PRINT_OUT("Encoded for AddressList Tlv %d bytes\n", encodedSize);
  }

  return (addrMsg->baseMsg.msgLength + MPLS_TLVFIXLEN);

}                               /* End: */

/*
 *  decode
 */
int Mpls_decodeLdpAdrMsg(mplsLdpAdrMsg_t * addrMsg, u_char * buff, int bufSize)
{
  int decodedSize = 0;
  u_int totalSize = 0;
  u_int stopLength = 0;
  u_int totalSizeParam = 0;
  u_char *tempBuf = buff;       /* no change for the buff ptr */
  mplsLdpTlv_t tlvTemp;

  /*
   *  decode the base part of the pdu message
   */
  memset(addrMsg, 0, sizeof(mplsLdpAdrMsg_t));
  decodedSize = Mpls_decodeLdpBaseMsg(&(addrMsg->baseMsg), tempBuf, bufSize);
  if (decodedSize < 0) {
    return MPLS_DEC_BASEMSGERROR;
  }
  PRINT_OUT("Decode BaseMsg for address msg on %d bytes\n", decodedSize);

  if ((addrMsg->baseMsg.flags.flags.msgType != MPLS_ADDR_MSGTYPE) &&
    (addrMsg->baseMsg.flags.flags.msgType != MPLS_ADDRWITH_MSGTYPE)) {
    PRINT_ERR("Not the right message type; expected adr and got %x\n",
      addrMsg->baseMsg.flags.flags.msgType);
    return MPLS_MSGTYPEERROR;
  }

  tempBuf += decodedSize;
  totalSize += decodedSize;

  if (bufSize - totalSize <= 0) {
    /* nothing left for decoding */
    PRINT_ERR("Adr msg does not have anything beside base msg\n");
    return totalSize;
  }

  PRINT_OUT("bufSize = %d,  totalSize = %d, addrMsg->baseMsg.msgLength = %d\n",
    bufSize, totalSize, addrMsg->baseMsg.msgLength);

  /* Have to check the baseMsg.msgLength to know when to finish.
   * We finsh when the totalSizeParam is >= to the base message length - the
   * message id length (4) 
   */

  stopLength = addrMsg->baseMsg.msgLength - MPLS_MSGIDFIXLEN;
  while (stopLength > totalSizeParam) {
    /*
     *  decode the tlv to check what's next
     */
    memset(&tlvTemp, 0, MPLS_TLVFIXLEN);
    decodedSize = Mpls_decodeLdpTlv(&tlvTemp, tempBuf, bufSize - totalSize);
    if (decodedSize < 0) {
      /* something wrong */
      PRINT_ERR("ADR msg decode failed for tlv\n");
      return MPLS_DEC_TLVERROR;
    }

    tempBuf += decodedSize;
    totalSize += decodedSize;
    totalSizeParam += decodedSize;

    switch (tlvTemp.flags.flags.tBit) {
      case MPLS_ADDRLIST_TLVTYPE:
        {
          decodedSize = Mpls_decodeLdpAdrTlv(&(addrMsg->addressList),
            tempBuf, bufSize - totalSize, tlvTemp.length);
          if (decodedSize < 0) {
            PRINT_ERR("Failure when decoding AdrList tlv from adr msg\n");
            return MPLS_DEC_ADRLISTERROR;
          }
          PRINT_OUT("Decoded for ADRLIST %d bytes\n", decodedSize);
          tempBuf += decodedSi