As fallback for failed lookup by RemoteHostId.
This will eventually be the primary lookup after most traffic is SSU2.
For now, only used to receive traffic from a peer that changed IP/port.
SSU 1/2 send destroy when replacing old session with new.
Prep for full SSU2 connection migration.
Use minimum MTU for IPv6 session confirmed to avoid PMTU issues
Set default MTU for known IPv6 tunnel brokers
Check for s mismatch in session confirmed RI
Don't put DateTime block after Termination block
Fix first message failed check
Log sent data packet size
Log tweaks
Reduce max consecutive message failures to fail session (SSU 1/2)
Set peer as unreachable for these failures
Reduce max consectutive session confirmed retransmissions
Fix session confirmed retransmission timing
Respond to relay tag request in data phase
Log tweaks
Fix setting local IPv6 MTU when firewalled
Fix publishing MTU when firewalled or hidden
Save local MTU when changing addresses, not when publishing
Add SSU2 MTU methods (no mod 16 required)
Allow MTU up to 1500 for SSU2 transport style
Disable SSU2 at startup if local MTU too low
Add code for bob rejecting alice peer test address
Don't allow MTU to exceed his MTU
Don't use a token about to expire
Send token with termination message
Add internal type to termination message
log tweaks
to make it more responsive to conditions and a more effective PMTU algorithm.
Move MTU up and down in increments rather than simply shift between min and max
Increase or decrease based on success or failure of each message
Only increase if the successful message was almost as large as current MTU
Clear increase/decrease counters when changing MTU the other way
Don't wait for 10 packets to increase MTU
Reduce max retransmissions from 30% to 10%
Caused SusiDNS and addressbook to be in a different context
addressbook config would be stored in base dir
and subscriptions would not load because it couldn't find i2ptunnel
