我正在尝试从数据包中获取源地址和目标地址。这就是我阅读数据包的方式:
private void debugPacket(ByteBuffer packet) {
int buffer = packet.get();
int ipVersion = buffer >> 4;
int headerLength = buffer & 0x0F;
headerLength *= 4;
buffer = packet.get(); //DSCP + EN
int totalLength = packet.getChar(); //Total Length
buffer = packet.getChar(); //Identification
buffer = packet.getChar(); //Flags + Fragment Offset
buffer = packet.get(); //Time to Live
int protocol = packet.get(); //Protocol
buffer = packet.getChar(); //Header checksum
String sourceIP = "";
buffer = packet.get(); //Source IP 1st Octet
sourceIP += ((int) buffer) & 0xFF;
sourceIP += ".";
buffer = packet.get(); //Source IP 2nd Octet
sourceIP += ((int) buffer) & 0xFF;
sourceIP += ".";
buffer = packet.get(); //Source IP 3rd Octet
sourceIP += ((int) buffer) & 0xFF;
sourceIP += ".";
buffer = packet.get(); //Source IP 4th Octet
sourceIP += ((int) buffer) & 0xFF;
String destIP = "";
buffer = packet.get(); //Destination IP 1st Octet
destIP += ((int) buffer) & 0xFF;
destIP += ".";
buffer = packet.get(); //Destination IP 2nd Octet
destIP += ((int) buffer) & 0xFF;
destIP += ".";
buffer = packet.get(); //Destination IP 3rd Octet
destIP += ((int) buffer) & 0xFF;
destIP += ".";
buffer = packet.get(); //Destination IP 4th Octet
destIP += ((int) buffer) & 0xFF;
String hostName;
try {
InetAddress addr = InetAddress.getByName(destIP);
hostName = addr.getHostName();
} catch (UnknownHostException e) {
hostName = "Unresolved";
}
Log.d(this.getClass().getSimpleName(), "Packet: IP Version=" + ipVersion + ", Header-Length=" + headerLength + ", Total-Length=" + totalLength
+ ", Destination-IP=" + destIP + ", Hostname=" + hostName + ", Source-IP=" + sourceIP+ ", Protocol=" + protocol);
}
它对前几个数据包工作正常,但有时我会在 packet.get()
行之一收到 BufferUnderflowException。我该如何防止这种情况?
最佳答案
真不敢相信我没早点发现这个。我忘了在 debugPacket(packet)
之后调用 packet.clear()
。
关于java - 从 ByteBuffer 中获取 IP 包数据,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/37246063/