$KAME: TODO,v 1.36 2001/09/19 09:41:39 sakane Exp $

Please send any questions or bug reports to snap-users@kame.net.

TODO list

URGENT
o The documents for users convenience.
o split log file based on client.  printf-like config directive, i.e.
  "logfile racoon.%s.log", should be useful here.
  -> beware of possible security issue, don't use sprintf() directly!
     make validation before giving a string to sprintf().
o save decrypted IKE packet in tcpdump format
o IPComp SA with wellknown CPI in CPI field.  how to handle it?
o better rekey

MUST
o multiple certificate payload handling.
o To consider the use with certificate infrastructure.  PXIX ???
o kmstat should be improved.
o Informational Exchange processing properly.
o require less configuration.  phase 2 is easier (as kernel presents racoon
  some hints), phase 1 is harder.  for example,
  - grab phase 2 lifetime and algorith configuration from sadb_comb payloads in
    ACQUIRE message.
  - give reasonable default behavior when no configuration file is present.
  - difficult items:
	how to guess a reasonable phase 1 SA lifetime
		(hardcoded default?  guess from phase 2 lifetime?)
	guess what kind of ID payload to use
	guess what kind of authentication to be used
	guess phase 1 DH group (for aggressive mode, we cannot negotiate it)
	guess if we need phase 2 PFS or not (we cannot negotiate it. so
		we may need to pick from "no PFS" or "same as phase 1 DH group")
	guess how we should negotiate lifetime
		(is "strict" a reasonable default?)
	guess which mode to use for phase 1 negotiation (is main mode useful?
		is base mode popular enough?)
o more acceptable check.

SHOULD
o psk.txt should be a database? (psk.db?)  psk_mkdb?
o Dynamically retry to exchange and resend the packet per nodes.
o To make the list of supported algorithm by sadb_supported payload
  in the SADB_REGISTER message which happens asynchronously.
o fix the structure of ph2handle.
  We can handle the below case.

  node A                            node B
    +--------------SA1----------------+
    +--------------SA2----------------+

  at node A:
  kernel
    acquire(A-B) ------> ph2handle(A=B) -----> ph1handle
                              |
                            policy
                             A=B
                             A=B

  But we can not handle the below case because there is no x?handle.

  node A                            node B                           node C
    +--------------SA1----------------+
    +------------------------------------------------SA2---------------+

  at node A:
  kernel
    acquire(A-C) ---+---> x?handle ---+---> ph2handle(A=B) -------> ph1handle
                    |        |        |
    acquire(A-B) ---+      policy     +---> ph2handle(A=C) -------> ph1handle
                            A=B
                            A=C

o consistency of function name.
o deep copy configuration entry to hander.  It's easy to reload configuration.
o don't keep to hold keymat values, do it ?
o local address's field in isakmpsa handler must be kicked out to rmconf.
o responder policy and initiator policy should be separated.
o for lifetime and key length, something like this should be useful.
  - propose N
  - accept between X and Y
o wildcard "accept any proposal" policy should be allowed.
o replay prevention
  - limited total number of session
  - limited session per peer
  - number of proposal
o full support for variable length SPI.  quickhack support for IPComp is done.

MAY
o Effective code.
o interaction between IKE/IPsec and socket layer.
  at this moment, IKE/IPsec failure is modeled as total packet loss to other
  part of network subsystem, including socket layer.  this presents the
  following behaviors:
  - annoyingly long timeouts on tcp connection attempt, and IKE failure;
    need to wait till tcp socket timeouts.
  - blackhole if there's mismatching SAs.
  we may be able to give socket layer some feedback from IKE/IPsec layer.
  still not sure if those make sense or not.
  for example:
  - send PRU_HOSTDEAD to sockets if IKE negotiation failed
    (sys/netkey/key.c:key_acquire2)
    to do this, we need to remember which ACQUIRE was caused by which socket,
    possibly into larval SAs.
  - PRU_QUENCH on "no SA found on output"
  - kick tcp retransmission timer on first SA establishment
o IKE daemon should handle situations where peer does not run IKE daemon
  (UDP port unreach for port 500) better.
  should use connected UDP sockets for sending IKE datagrams.
o rate-limit log messages from kernel IPsec errors, like "no SA found".

TO BE TESTED.
o IKE retransmit behavior
	see, draft-*-ipsec-rekeying*.txt
o Reboot recovery (peer reboot losing it's security associations)
	see, draft-*-ipsec-rekeying*.txt
o Scenarios
	- End-to-End transport long lived security associations
	  (over night, data transfer >1Gb) with frequent dynamic rekey
	- End-to-GW tunnel long lived security associations
	  (over night, data transfer >1Gb) with frequent dynamic rekey
	- Policy change events while under SA load
	- End-to-End SA through IPsec tunnels, initiation both ways
	- Client End-to-End through client-to-GW tunnel SA, initiate from
	  client for tunnel, then initiation both ways for end-to-end
	- Client-to-GW transport SA for secure management
o behavior to receive multiple auth method proposals and AND proposal

and to be written many many.