hi, i have n number of packet and i have three different message. beginning message , continuation message and end message. when beginning message received i have to store the message and continuation of message alo be included and when it comes to end message i have to reassembled them. Packet 1 : fragmentation, beginning message(id=1) Packet 2 : fragmentation, continuation message(id=1) Packet 3 : fragmentation, beginning message(id=2) Packet 4 : fragmentation, beginning message(id=3) Packet 5 : fragmentation, continuation message(id=1) Packet 6 : fragmentation, end message(id=1) how can i reassemble these messages in my dissectors? This question is marked "community wiki". asked 27 May '17, 21:30  ghader edited 30 May '17, 08:22  JeffMorriss ♦ |
One Answer:
Since you didn't say otherwise I'm assuming your custom dissector is in C (rather than Lua). Fundamentally you want to use the routines in epan/reassemble.{h,c}. From the looks of it you may be able to use the answered 30 May '17, 08:21 JeffMorriss ♦ |
So how are those three types of message indicated? Is a non-fragmented message one that's marked as neither beginning, nor continuation, nor end? Or is it marked in some other way? What if a message has only two fragments - is one marked as beginning and the other marked as end?
And do the IDs indicate what message is fragmented, so that, with those 6 packets, only the message with an ID of 1 can be reassembled?
in message packets, there is a flag(message type) that indicate type of message(b,c,e).some message has only two fragments - is one marked as beginning and the other marked as end.the IDs dont indicate what message is fragmented. there is a counter in each message that increase each time send a packet.
Packet 1 : fragmentation, beginning message(id=1),n=10
Packet 2 : fragmentation, continuation message(id=1),n=11
Packet 3 : fragmentation, beginning message(id=2),n=15
Packet 4 : fragmentation, beginning message(id=3),n=20
Packet 5 : fragmentation, continuation message(id=1),n=12
Packet 6 : fragmentation, end message(id=1),n=13
So all messages are fragmented - there's no message type that's "it's all here, no fragments"? Or is that a fourth message type?
In your example, what indicates which message packets 2 and 5 are continuations of, and what message packet 6 is the end of?