1. Multicast Source Filter API draft-ietf-idmr-msf-api-00.txt Dave Thaler (Microsoft) Bill Fenner (AT&T Research) Bob Quinn (Stardust.com)

2. Goals Express multicast source filters for IPv4 and IPv6 Provide version-independent API not present in RFC 2553 Basic (delta-based) version for most uses Advanced version for large atomic operations, switching modes, etc. Minimize changes to existing API

3. Existing IPv4 Multicast API struct ip_mreq { struct in_addr imr_multiaddr; /* IP multicast address of group */ struct in_addr imr_interface; /* local IP address of interface */ }; socket options : IP_{ADD,DROP}_MEMBERSHIP

4. Semantics of Existing API “Delta”-based –To join/leave a set of (sub)set of groups, call API once for each group to join or leave NOT “final-state” based (don’t specify new set of groups to be joined to) Often join multiple groups (e.g., different media), but this is not a problem

5. Structure for new IPv4 basic operations struct ip_mreq_source { struct in_addr imr_multiaddr; /* group address */ struct in_addr imr_sourceaddr;/* source address */ struct in_addr imr_interface; /* iface address*/ };

6. Socket Operations (setsockopt) IP_{ADD,DROP}_SOURCE_MEMBERSHIP - for inclusion list changes IP_{ADD,DROP}_MEMBERSHIP - existing API for exclude mode IP_{ALLOW,BLOCK}_SOURCE - for exclusion list changes

7. Semantics of Basic API For source-inclusion, just do IP_ADD_SOURCE_MEMBERSHIP per source For source-exclusion, do IP_ADD_MEMBERSHIP, and IP_DROP_SOURCE_MEMBERSHIP per source Functionally equivalent to abstract API Always delta-based so more consistent with existing API

8. Advanced API Basic API doesn’t let app switch modes without leaving group Basic API is very inefficient with large source lists Advanced API is final-state based: just set the complete filter

9. Structure for advanced IPv4 operations struct ip_msfilter { struct in_addr imsf_multiaddr; /* group address */ struct in_addr imsf_interface; /* iface address */ uint32_t imsf_fmode; /* filter mode */ uint32_t imsf_numsrc; /* # sources */ struct in_addr imsf_slist[1]; /* source list */ }; #define IP_MSFILTER_SIZE(numsrc)... (size of buffer with numsrc sources in list) fmode=MCAST_{INCLUDE,EXCLUDE}

10. Socket Operations setsockopt: – IP_MULTICAST_FILTER ioctl: – SIO_GET_MULTICAST_FILTER Open issue: change set to ioctl SIO_SET_MULTICAST_FILTER?

11. Protocol-Independent API E.g. Resolve DNS name to sockaddr Could be v4 or v6, want to use same API in spirit of RFC 2553 Just need to use structures containing sockaddr_storage instead of addresses Use indices to identify interfaces (not addresses!) as in current IPv6-specific API.

12. Basic Structures struct ip_mcast_req { uint32_t imr_interface; struct sockaddr_storage imr_group; }; struct ip_mcast_source_req { uint32_t imsr_interface; struct sockaddr_storage imsr_group; struct sockaddr_storage imsr_source; };

13. Advanced Structure struct ip_mcast_filter { uint32_t imf_interface; struct sockaddr_storage imf_group; uint32_t imf_fmode; uint32_t imf_numsrc; struct sockaddr_storage imf_slist[1]; }; #define IP_MCAST_FILTER_SIZE(numsrc)... (size of buffer with numsrc sources)

14. Socket Operations setsockopt: –IP_{JOIN,LEAVE}_GROUP –IP_{JOIN,LEAVE}_GROUP_SOURCE –IP_{BLOCK,ALLOW}_SOURCE ioctl –SIO_{GET,SET}_MULTICAST_FILTER