NAME

  CookieEchoWithBadTag.seq - COOKIE-ECHO chunk is received with invalid Verification Tag

PURPOSE

  To check that if COOKIE-ECHO is received chunk with invalid Verification
  Tag and T bit is set, the endpoint should silently discard the packet
  and take no further action.

SYNOPSIS

  ./CookieEchoWithBadTag.seq [-tooloption ...] -pkt ./CookieEchoWithBadTag.def
    -tooloption : v6eval tool option
  See Also: ../common/STD_PKT_COMMON.def
            ../common/SCTP_COMMON.def

PRE-TEST CONDITION

  Association is not established between endpoint A an B. Arrange the
  data in endpoint A such that COOKIE-ECHO message with a different
  verification tag (different from what received in INIT-ACK) is sent
  in response to INIT-ACK.

TEST PROCEDURE

  Endpoint A                           Endpoint B                ULP
  (CLOSED)                             (CLOSED)

  INIT            ---------------->

                  <-----------------     INIT-ACK
  
  COOKIE-ECHO     ----------------->     Silently discard
  (with invalid Verification Tag)
  COOKIE-ECHO     ----------------->

                  <------------------    COOKIE-ACK

  TEST DESCRIPTION:

  1. Attempt to initiate an association from endpoint A to B. Send 
     COOKIE-ECHO message (in response to INIT-ACK) with verification 
     tag value different from received in INIT-ACK.
     Record the message sequence using a signal emulator.
  2. Check A: COOKIE-ECHO message is silently discarded.
  3. Check B: Was the message sequence as above.

NOTE

  None

REFERENCE

  RFC 4960

  8.5.1.  Exceptions in Verification Tag Rules

    D) Rules for packet carrying a COOKIE ECHO

    -   When sending a COOKIE ECHO, the endpoint MUST use the value of
        the Initiate Tag received in the INIT ACK.

    -   The receiver of a COOKIE ECHO follows the procedures in Section
        5.