HI, A potential issue came up on v6ops list in IETF that Linux stack changes the flow label for a connection at every RTO, this is the feature where we change the txhash on a failing connection to try to find a route (the flow label is derived from the txhash). The problem with changing the flow label for a connection is that it may cause problems when stateful middleboxes are in the path, for instance if a flow label change causes packets for a connection to take a different route they might be forwarded to a different stateful firewall that didn't see the 3WHS so don't have any flow state and hence drop the packets.
I was under the assumption that we had a sysctl that would enable changing the txhash for a connection and the default was off so that flow labels would be persistent for the life of the connection. Looking at the code now, I don't see that safety net, it looks like the defauly behavior allows changing the hash. Am I missing something? Thanks, Tom
