Christoph Paasch

Can you capture a packet-trace on the sender side and share it with us? Thanks!

Hello, seems like you also have an interface with a 172/8 network. Can you disable this interface for MPTCP (on both, client and server) with ```ip link set dev [itf]...

Hello, at this stage in the output path the TCP/IP-headers haven't been written yet, because the scheduler needs to make the decision on which subflow to choose before the TCP/IP...

But how would the application pass this information down to the kernel? The application can't write things into a TCP/IP-header.

Can you try disabling MPTCP-checksum and report back? ```sysctl -w net.mptcp.mptcp_checksum=0```

Ah! Thanks for confirming! There is a problem with MPTCP-checksums. I will try to repro...

Hello, do you still see this issue? I have been trying to repro, but without success. Do you have a packet-trace of this scenario? How many subflows did you create?...

@faddat ```skb->cb``` is in ```struct sk_buff```. We had to increase it from 48 bytes to 56 bytes, to accomodate for the MPTCP-specific fields in ```struct tcp_skb_cb``` Reducing it back to...

@faddat - looking more into it, it can probably easily be done by reordering some fields, as we introduced a hole in the struct tcp_skb_cb. You can check with ```pahole```...

@faddat And it's me again :) Actually, seems like we can just reduce the size down to 48 bytes again in ```struct sk_buff```. If you want, you can submit a...