How to use

recvPacket

method

in

libcore.net.RawSocket

/**
 * Reads a raw packet into the specified buffer, with the
 * specified timeout.  If the destPort is -1, then the IP
 * destination port is not verified, otherwise only packets
 * destined for the specified UDP port are returned.  Returns the
 * length actually read.  No indication of overflow is signaled.
 * The packet data will start at the IP header (EthernetII
 * dest/source/type headers are removed).
 */
public int read(byte[] packet, int offset, int byteCount, int destPort,
  int timeoutMillis) {
  if (packet == null) {
    throw new NullPointerException("packet == null");
  }
  Arrays.checkOffsetAndCount(packet.length, offset, byteCount);
  if (destPort > 65535) {
    throw new IllegalArgumentException("Port out of range: "
      + destPort);
  }
  return recvPacket(fd, packet, offset, byteCount, destPort,
    timeoutMillis);
}

/**
 * Reads a raw packet into the specified buffer, with the
 * specified timeout.  If the destPort is -1, then the IP
 * destination port is not verified, otherwise only packets
 * destined for the specified UDP port are returned.  Returns the
 * length actually read.  No indication of overflow is signaled.
 * The packet data will start at the IP header (EthernetII
 * dest/source/type headers are removed).
 */
public int read(byte[] packet, int offset, int byteCount, int destPort,
  int timeoutMillis) {
  if (packet == null) {
    throw new NullPointerException("packet == null");
  }
  Arrays.checkOffsetAndCount(packet.length, offset, byteCount);
  if (destPort > 65535) {
    throw new IllegalArgumentException("Port out of range: "
      + destPort);
  }
  return recvPacket(fd, packet, offset, byteCount, destPort,
    timeoutMillis);
}

/**
 * Reads a raw packet into the specified buffer, with the
 * specified timeout.  If the destPort is -1, then the IP
 * destination port is not verified, otherwise only packets
 * destined for the specified UDP port are returned.  Returns the
 * length actually read.  No indication of overflow is signaled.
 * The packet data will start at the IP header (EthernetII
 * dest/source/type headers are removed).
 */
public int read(byte[] packet, int offset, int byteCount, int destPort,
  int timeoutMillis) {
  if (packet == null) {
    throw new NullPointerException("packet == null");
  }
  Arrays.checkOffsetAndCount(packet.length, offset, byteCount);
  if (destPort > 65535) {
    throw new IllegalArgumentException("Port out of range: "
      + destPort);
  }
  return recvPacket(fd, packet, offset, byteCount, destPort,
    timeoutMillis);
}

/**
 * Reads a raw packet into the specified buffer, with the
 * specified timeout.  If the destPort is -1, then the IP
 * destination port is not verified, otherwise only packets
 * destined for the specified UDP port are returned.  Returns the
 * length actually read.  No indication of overflow is signaled.
 * The packet data will start at the IP header (EthernetII
 * dest/source/type headers are removed).
 */
public int read(byte[] packet, int offset, int byteCount, int destPort,
  int timeoutMillis) {
  if (packet == null) {
    throw new NullPointerException("packet == null");
  }
  Arrays.checkOffsetAndCount(packet.length, offset, byteCount);
  if (destPort > 65535) {
    throw new IllegalArgumentException("Port out of range: "
      + destPort);
  }
  return recvPacket(fd, packet, offset, byteCount, destPort,
    timeoutMillis);
}

/**
 * Reads a raw packet into the specified buffer, with the
 * specified timeout.  If the destPort is -1, then the IP
 * destination port is not verified, otherwise only packets
 * destined for the specified UDP port are returned.  Returns the
 * length actually read.  No indication of overflow is signaled.
 * The packet data will start at the IP header (EthernetII
 * dest/source/type headers are removed).
 */
public int read(byte[] packet, int offset, int byteCount, int destPort,
  int timeoutMillis) {
  if (packet == null) {
    throw new NullPointerException("packet == null");
  }
  Arrays.checkOffsetAndCount(packet.length, offset, byteCount);
  if (destPort > 65535) {
    throw new IllegalArgumentException("Port out of range: "
      + destPort);
  }
  return recvPacket(fd, packet, offset, byteCount, destPort,
    timeoutMillis);
}

/**
 * Reads a raw packet into the specified buffer, with the
 * specified timeout.  If the destPort is -1, then the IP
 * destination port is not verified, otherwise only packets
 * destined for the specified UDP port are returned.  Returns the
 * length actually read.  No indication of overflow is signaled.
 * The packet data will start at the IP header (EthernetII
 * dest/source/type headers are removed).
 */
public int read(byte[] packet, int offset, int byteCount, int destPort,
  int timeoutMillis) {
  if (packet == null) {
    throw new NullPointerException("packet == null");
  }
  Arrays.checkOffsetAndCount(packet.length, offset, byteCount);
  if (destPort > 65535) {
    throw new IllegalArgumentException("Port out of range: "
      + destPort);
  }
  return recvPacket(fd, packet, offset, byteCount, destPort,
    timeoutMillis);
}

/**
 * Reads a raw packet into the specified buffer, with the
 * specified timeout.  If the destPort is -1, then the IP
 * destination port is not verified, otherwise only packets
 * destined for the specified UDP port are returned.  Returns the
 * length actually read.  No indication of overflow is signaled.
 * The packet data will start at the IP header (EthernetII
 * dest/source/type headers are removed).
 */
public int read(byte[] packet, int offset, int byteCount, int destPort,
  int timeoutMillis) {
  if (packet == null) {
    throw new NullPointerException("packet == null");
  }
  Arrays.checkOffsetAndCount(packet.length, offset, byteCount);
  if (destPort > 65535) {
    throw new IllegalArgumentException("Port out of range: "
      + destPort);
  }
  return recvPacket(fd, packet, offset, byteCount, destPort,
    timeoutMillis);
}