TCP options order changed in FreeBSD 7, incompatible with some routers

Mike Silbersack silby at silby.com
Wed Mar 12 21:28:49 PDT 2008


On Wed, 12 Mar 2008, Mike Silbersack wrote:

> I think we will need to fix tcpdump before trying to finish diagnosing this 
> problem.  We were missing key information before.
>
> -Mike

Hm, that was far easier than expected.  Patch attached.

Here's what the two tcpdumps show now:

6.3:
IP A > B : S 2575736483:2575736483(0) ack 1762868649 win 65535 <mss 1460,sackOK,eol,eol>

7.0:
IP A > B : S 3304309835:3304309835(0) ack 710421411 win 65535 <mss 1380,sackOK,eol,nop>

That makes the problem quite a bit more clear.  Anyone working on this 
issue should apply this patch ASAP.

-Mike
-------------- next part --------------
--- print-tcp.c.old	2008-03-12 23:21:52.000000000 -0500
+++ print-tcp.c	2008-03-12 23:24:50.000000000 -0500
@@ -637,8 +637,10 @@
 			if (datalen != len)
 				(void)printf("[len %d]", len);
 			ch = ',';
+#if 0
 			if (opt == TCPOPT_EOL)
 				break;
+#endif
 		}
 		putchar('>');
 	}


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