Subject: [magma] Some question about RFC3810

From: "K.Kawaguchi" <[email-masked]>
Date: Thu, 4 Dec 2008 11:20:30 +0900

Hi All,

I would like to check some specification details about RFC3810.
I am sorry to be long.

------------------------------------------------------------------------
1. Setting the Other Querier Present timer

---
7.6.2.  Querier Election

   When a router receives a query with a lower IPv6 address than its
   own, it sets the Other Querier Present timer to Other Querier Present
   Timeout; if it was previously in Querier state, it switches to Non-
   Querier state and ceases to send queries on the link.  After the
   Other Querier Present timer expires, it should re-enter the Querier
   state and begin sending General Queries.
---
5.1.15.  Destination Addresses for Queries

   In MLDv2, General Queries are sent to the link-scope all-nodes
   multicast address (FF02::1).  Multicast Address Specific and
   Multicast Address and Source Specific Queries are sent with an IP
   destination address equal to the multicast address of interest.
   *However*, a node MUST accept and process any Query whose IP
   Destination Address field contains *any* of the addresses (unicast or
   multicast) assigned to the interface on which the Query arrives. This
   might be useful, e.g., for debugging purposes.
---

(1) Does the target query of querier election require only a General
    Query whose destination addresses are link-scope all-nodes multicast
    address (FF02::1)?

    - If it allows except a General Query, an attacker is transmitting
      a Multicast Address Specific Query and a Multicast Address and
      Source Specific Query using a lower source address, and can
      suppress the General Query transmission by other routers.

    - If it allows the interface related address of a router in a
      destination address, an attacking force is transmitting a General
      Query only to all routers, and can block a General Query to
      listeners.

------------------------------------------------------------------------
2. Query reception and variable adoption in a router

---
5.1.8.  QRV (Querier's Robustness Variable)

   Routers adopt the QRV value from the most recently received Query as
   their own [Robustness Variable] value, unless that most recently
   received QRV was zero, in which case they use the default [Robustness
   Variable] value specified in section 9.1, or a statically configured
   value.
---
5.1.9.  QQIC (Querier's Query Interval Code)
   Multicast routers that are not the current Querier adopt the QQI
   value from the most recently received Query as their own [Query
   Interval] value, unless that most recently received QQI was zero, in
   which case the receiving routers use the default [Query Interval]
   value specified in section 9.2.
---
5.1.15.  Destination Addresses for Queries

   In MLDv2, General Queries are sent to the link-scope all-nodes
   multicast address (FF02::1).  Multicast Address Specific and
   Multicast Address and Source Specific Queries are sent with an IP
   destination address equal to the multicast address of interest.
   *However*, a node MUST accept and process any Query whose IP
   Destination Address field contains *any* of the addresses (unicast or
   multicast) assigned to the interface on which the Query arrives. This
   might be useful, e.g., for debugging purposes.
---

(1) Whenever a router receives a query from other router, Does adopt QRV
    and QQIC regardless of the variants and source address priority of a
    query message?

    - If only the query by a querier is a target,
      The variable of a router is not unified until a router finds a
      true querier after starting.
      The router needs to record the address of the present querier.

(2) If a router adopts QRV and QQIC in a query whose destination address
    is an unicast, a different value is caused between routers.
    Therefore, does not adopt QRV and QQIC in the query whose
    destination address is not multicast?

(3) When a router becomes a querier, does continue to use the value of
    the previous received query? Or, does a router use an own preset
    value? Or, no specs?

------------------------------------------------------------------------
3. Last Listener Query Time

9.8.  Last Listener Query Interval
9.9.  Last Listener Query Count
9.10.  Last Listener Query Time

(1) How is the value of LLQT of each router unified on MLDv2 protocol?
    Do QRV and QQIC in a Multicast Address Specific Query and a
    Multicast Address and Source Specific Query correspond to LLQC and
    LLQI?

------------------------------------------------------------------------
4. Destination Addresses for Reports

---
5.2.14.  Destination Addresses for Reports

   Version 2 Multicast Listener Reports are sent with an IP destination
   address of FF02:0:0:0:0:0:0:16, to which all MLDv2-capable multicast
   routers listen (see section 11 for IANA considerations related to
   this special destination address).  A node that operates in version 1
   compatibility mode (see details in section 8) sends version 1 Reports
   to the multicast address specified in the Multicast Address field of
   the Report.  In addition, a node MUST accept and process any version
   1 Report whose IP Destination Address field contains *any* of the
   IPv6 addresses (unicast or multicast) assigned to the interface on
   which the Report arrives.  This might be useful, e.g., for debugging
   purposes.
---

(1) Does the MLDv2 report message which has a multicast address or an
    IPv6 address of IF in a destination address field discard?

------------------------------------------------------------------------
5. packet error process

---
6.2.  Action on Reception of a Query

   Upon reception of an MLD message that contains a Query, the node
   checks if the source address of the message is a valid link-local
   address, if the Hop Limit is set to 1, and if the Router Alert option
   is present in the Hop-By-Hop Options header of the IPv6 packet.  If
   any of these checks fails, the packet is dropped.
---
---
7.6.  Action on Reception of Queries

   Upon reception of an MLD message that contains a Query, the router
   checks if the source address of the message is a valid link-local
   address, if the Hop Limit is set to 1, and if the Router Alert option
   is present in the Hop-By-Hop Options header of the IPv6 packet.  If
   any of these checks fails, the packet is dropped.
---

(1) Is ICMPv6 error replied when a destination address is a unicast?

Best Regards
--
Kiyoaki Kawaguchi

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