1. SEND Linux Implementation Report Jonathan Wood DoCoMo USA Labs IETF 58 November 2003

2. Overview Platform –Linux 2.5 / 2.6 –OpenSSL 0.9.7 (for crypto and ASN.1) –Radvd 0.7.2 (modified for secure RD) –Iproute2 2.4.7 (modified for CGAs) Complete implementation of SEND, no major issues found –Implementing a robust timestamp cache is tricky, however.

3. Design SEND not performance critical, so keep as much as possible out of the kernel Userspace: –Public key crypto –General ASN.1 –DCS/DCA –Utilities and management Userspace daemon handles crypto and RD operations for kernel

4. Design Kernel –CGA verification and generation –Specialized ASN.1 parser for CGA parameters –Primary focus is to hand all other secure ND and RD tasks off to userspace daemon –Keeps secure ND and RD processing out of the interrupt context

5. Complexity RD Certificate profile is single most complex piece (~3800 lines of code) CGA: ~2200 lines (kernel + user, including management tool) User crypto: ~1200 lines (mostly OpenSSL glue) Additional kernel code: ~2800 lines

6. Rough Performance Numbers Two hosts, 1.2GHz Pentium IV 100MBit Ethernet CGA Sec: 1 1024 bit RSA keys ND –Flush neighbor cache –Send a ping (Invoking secure ND) –Ping reports RTT –Instrumented code reports crypto timings

7. ND Numbers Average first ping RTT (requiring secure ND): 24ms Crypto took 21ms on average –Signing is slow, verification is fast For reference: –Average ping RTT (with insecure ND): 0.46ms –Average ping RTT (without ND): 0.13ms

8. ND Numbers Detail

9. RD Numbers Certificate chain four deep, each certificate with PKIX IP Extensions Two scenarios: –RA receiver does not have certificates cached, so it must use DCS/DCA exchange (slower) –RA receiver has all needed certificates cached Measured time from sending RA until receipt of DAD NS.

10. RD Without Cached Certificates Average total time: 31ms Crypto took 27ms on average Procedure: –Delete autoconfigured address on host, if necessary –Flush host’s certificate cache –Send RA –Sniffer and instrumented code reports timings

11. RD Detail (Uncached)

12. RD with Cached Certificates No DCS/DCA exchange needed Average total time: 13ms Average crypto time: 10ms Proceedure: –Delete autoconfigured address on host, if necessary –Send RA –Sniffer and instrumented code reports timings

13. RD Detail (cached)

14. Conclusion Implementing SEND is straightforward. –No major problems. Performance is about 2 orders of magnitude slower than without SEND. –Public key crypto is performance intensive. But ND and RD are not typically critical path items. –Mobility may need attention.