RFC 2133 (rfc2133) - Page 2 of 32
Basic Socket Interface Extensions for IPv6
Alternative Format: Original Text Document
RFC 2133 IPv6 Socket Interface Extensions April 1997 3.3. Socket Address Structure for 4.3BSD-Based Systems ......... 6 3.4. Socket Address Structure for 4.4BSD-Based Systems ......... 7 3.5. The Socket Functions ...................................... 8 3.6. Compatibility with IPv4 Applications ...................... 9 3.7. Compatibility with IPv4 Nodes ............................. 9 3.8. IPv6 Wildcard Address ..................................... 10 3.9. IPv6 Loopback Address ..................................... 11 4. Interface Identification .................................... 12 4.1. Name-to-Index ............................................. 13 4.2. Index-to-Name ............................................. 13 4.3. Return All Interface Names and Indexes .................... 14 4.4. Free Memory ............................................... 14 5. Socket Options .............................................. 14 5.1. Changing Socket Type ...................................... 15 5.2. Unicast Hop Limit ......................................... 16 5.3. Sending and Receiving Multicast Packets ................... 17 6. Library Functions ........................................... 19 6.1. Hostname-to-Address Translation ........................... 19 6.2. Address To Hostname Translation ........................... 22 6.3. Protocol-Independent Hostname and Service Name Translation 22 6.4. Socket Address Structure to Hostname and Service Name ..... 25 6.5. Address Conversion Functions .............................. 27 6.6. Address Testing Macros .................................... 28 7. Summary of New Definitions .................................. 29 8. Security Considerations ..................................... 31 9. Acknowledgments ............................................. 31 10. References ................................................. 31 11. Authors' Addresses ......................................... 32 1. Introduction While IPv4 addresses are 32 bits long, IPv6 interfaces are identified by 128-bit addresses. The socket interface make the size of an IP address quite visible to an application; virtually all TCP/IP applications for BSD-based systems have knowledge of the size of an IP address. Those parts of the API that expose the addresses must be changed to accommodate the larger IPv6 address size. IPv6 also introduces new features (e.g., flow label and priority), some of which must be made visible to applications via the API. This memo defines a set of extensions to the socket interface to support the larger address size and new features of IPv6. Gilligan, et. al. Informational
