Would it be possible to add ability to rewrite windows scale of SYN SYN-ACK packets to throttle download speed of TCP connections that support window scaling?
that options would be nice!
rewrite?.. client and server should support it, not router… no?
btw, “Linux kernels (from 2.6.8, August 2004) have enabled TCP Window Scaling by default”
I think you might have mis-understood what I think he might have wanted.
If the client and server support TCP window scaling, there will be a window scaling factor as a TCP option. Re-writing it could effectively shape a client using its own slow start algorithm or one can completely break it. Removing the window scale option on SYN could disable some TCP extensions, optimizing really low bandwidth networks. This is basically a hack to override client side optimization.
You shouldn’t increase the window scaling factor on the router unless you know the client has a large maximum receive window… but it would be nice if it could be done anyway 
Check this RFC for more on the window scaling factor - http://tools.ietf.org/html/rfc1323#page-8
A mangle rule which lets you modify any offset of a packet and a condition which works like the wireshark splice option would be really nice for us geeks 
indeed, very useful and maybe a new CoDel/fq_codel queue type..
Maybe on ros7
We must stop saying that. You just delayed ROS7 by another year now 
im afraid thats imply different IMPLEMENTATION of certain things.
eg support of things absent in 80% routers firmwares like:
ECN/Backward ECN.STCP, DCTCP, WRED/RRED, BLUE(particularly SFB and RSFB), GREEN, PURPLE, TCP Cookie Transactions
had to be implemented.
eg basic ECN support and AQM protocols of choice(with expanding later) would be first step, then TCP Cookie Transactions.
but its Inbearbly HUGE amount of work for such Tiny company of MikroTik do do it ALONE, im afraid :=(
same about port control protocol, DNSCurve, decent 802.1X-2010 implementation(with extension and adjaced things) and etc and etc (like say moving further to SDN, OpenFlow and improving AdHoc protocols/routing/networking).