Router Advertisements for Routing between Moving Networks draft-petrescu-autoconf-ra-based-routing-00.txt Presenter: Alexandru Petrescu IETF 78 Maastricht 29 July 2010, AUTOCONF Working Group Slide 1

Outline Problems: once addresses and prefixes are assigned – how to update routing tables. ICMPv6 extension Topology and Message Exchange Diagrams Conceptual Algorithm on MR3; scalability Recent remarks (from AUTOCONF, MEXT and private). Implementation Slide 2

Problem Slide 3 MR1 LFN1 MR2 LFN2 ?Routing tables? Self-formed link-local addresses Prefixes pre-configured

ICMPv6 Extension Router Advertisement is a message format defined in [RFC4861] as an ICMPv6 message. The document [RFC5175] proposes an option for RA extensibility: IPv6 Router Advetisement Flags Option. We propose to reserve bit 16 for Mobile Network Prefixes | Type | Length |M| Bit fields available for assignment | 'M' - Mobile Network Prefix present. Set to 1 if this Router Advertisement contains a Mobile Network Prefix. If the RA Flags Option contais the flag M, and set to 1, then the Router Advertisement MUST contain a Route Information Option [RFC4191] followed optionally by a Source-Link Layer Address Option [RFC4861]. (If this SLLAO option is used then it avoids the necessity of doing NS/NA exchange for the link-local address of the Gateway entry in the data structure mentioned earlier.) Slide 4

Topology and Message Exchange Diagrams MR-to-MR 2001:db8:3::/64 egress MR1 Net1 LFN11 MR3 Net3 LFN31 WiFi essid: “V3” channel: 9 mode: managed fe80::MR1_egress 2001:db8:1::/64 fe80::MR3_egress fe80::MR1_ingressfe80::MR3_ingress eth0 2001:db8:2::/64 egress MR2 Net2 LFN21 WiFi essid: “V2” channel: 9 mode: managed fe80::MR2_egress fe80::MR2_ingress eth0 WiFi essid: “V1” channel: 9 mode: managed Simultaneous MLD “JOIN” MR1MR2MR3 RA1: RA3: RA2: Phase 1 Phase 2 Simultaneous power-up of 3 MRs. Slide 5 WiFi essid: “V2V” channel: 3 mode: ad-hoc

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More Message Exchange Diagrams MR1MR2MR3 MLD “JOIN” RA1: RA3: RA2: RS MR1MR2MR3 RA1 used for deletion MNP1, flag ‘D’, or lifetime ‘0’ Upon receipt of this RA, MR2 and 3 delete their routes for MNP1 from their routing tables. MR1MR2MR3 RA1: RA2: RS Timeout Deletion Renewal, eventually Arrival of MR3 in a setting of MR1 and MR2. Timed out expiration and deletion. Explicit deletion. Slide 7

Conceptually – an Algorithm on MR3 (1)Send an RA containing the prefix(es) allocated to its subnets to which the ingress interfaces are connected (2) "Join" the all-routers multicast address with link-scope, on its egress interface (3) Send a Router Solicitation (RS) on its egress interface requesting RAs from MR1 and MR2 (4) Receive their special RAs: RA1 and RA2 (5) For each received RA, extract the source address and the prefixes and insert the corresponding number of routing table entries; these entries will help reach the LFNs in the moving networks of MR1 and MR2. Slide 8

Scalability Dst prefixGatewayDev 2001:db8:2::/64fe80::MR2_egressegress 2001:db8:3::/64fe80::MR3_egressegress 2001:db8:n::/64fe80::MRn_egressegress 2001:db8:1::/64« connected »ingress Routing table on MR1 MR1 LFN11 MR2 LFN12 LFN1n LFN21 LFN22 LFN2m MR3 LFN21 LFN22 LFN2m MRn LFN11 LFN12 LFN1n Number of entries equals the number of Mobile Routers at the scene. Dst prefixGatewayDev 2001:db8:1::/64« connected »eth0 defaultfe80::MR1_ingresseth0 Routing table on LFN11 Number of entries is constant. Slide 9

Security Example risk: attacker MR claims towards other MRs that it owns the MNP of a victim MR – victim MR no longer receives its traffic. More threats. Is SeND appropriate. Certificates when PKI infrastructure is absent. Ongoing work. Slide 10

Bug in distinctor of prefixes (/64 instead of /24) Use of distinctive ESSIDs on egress and ingress interfaces Use of link-local addresses (notation, pertinence) Address spoofing mode not good How is MNP provided initially? Addressing model not new and inline with IPv6 addressing arch Collective « we » look at addres/prefix autoconf w/o restrictions for packet relaying via same interface Is this multi-hop? Adapted to MEXT or AUTOCONF? [Teco, Chris, Ulrich, Henning, ThomasC – discussion above] Concept of prefix ownership, SeND Is MR2 relaying between 1 and 3 (if so packet rcvd on multiple paths?) Specifics on Route Deletion, RS used for. Have I checked AODV and similar [Antti] Remarks from AUTOCONF and MEXT WGs Slide 11

Wrong address of a co-author Need to separate the addressing model from protocol Private Remarks Slide 12

Implementation Extensions to ICMP Router Advertisements sent on the egress interface Implementation on linux with radvd 1.4 Packet Dissectors for Wireshark, for the packet formats Link-layer security on egress using WPA-NONE PSK TKIP/AES (yes, it is secure); and WEP too some times. Slide 13

More on the Addressing Model Slide 14

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Thanks in advance to the note takers! Comments Slide 16