tst_addr_and_pro_family - IPv6 Address Family and Protocol Family
Check if we have defined IPv6 Address Family and Protocol Family
./tst_addr_and_pro_family [-tooloption ...] -tooloption : v6api tool option
1. Check if we have defined IPv6 Address Family name AF_INET6 2. Check if we have defined IPv6 Address Family name PF_INET6 3. Check if AF_INET6 equal to PF_INET6
None
RFC 3493
3.3 Socket Address Structure for 4.3BSD-Based Systems
In the socket interface, a different protocol-specific data structure is defined to carry the addresses for each protocol suite. Each protocol-specific data structure is designed so it can be cast into a protocol-independent data structure -- the "sockaddr" structure. Each has a "family" field that overlays the "sa_family" of the sockaddr data structure. This field identifies the type of the data structure.
The sockaddr_in structure is the protocol-specific address data structure for IPv4. It is used to pass addresses between applications and the system in the socket functions. The following sockaddr_in6 structure holds IPv6 addresses and is defined as a result of including the <netinet/in.h> header:
struct sockaddr_in6 { sa_family_t sin6_family; /* AF_INET6 */ in_port_t sin6_port; /* transport layer port # */ uint32_t sin6_flowinfo; /* IPv6 flow information */ struct in6_addr sin6_addr; /* IPv6 address */ uint32_t sin6_scope_id; /* set of interfaces for a scope */ };
This structure is designed to be compatible with the sockaddr data structure used in the 4.3BSD release.
The sin6_family field identifies this as a sockaddr_in6 structure. This field overlays the sa_family field when the buffer is cast to a sockaddr data structure. The value of this field must be AF_INET6.
The sin6_port field contains the 16-bit UDP or TCP port number. This field is used in the same way as the sin_port field of the sockaddr_in structure. The port number is stored in network byte order.
The sin6_flowinfo field is a 32-bit field intended to contain flow- related information. The exact way this field is mapped to or from a packet is not currently specified. Until such time as its use is specified, applications should set this field to zero when constructing a sockaddr_in6, and ignore this field in a sockaddr_in6 structure constructed by the system.
The sin6_addr field is a single in6_addr structure (defined in the previous section). This field holds one 128-bit IPv6 address. The address is stored in network byte order.
The ordering of elements in this structure is specifically designed so that when sin6_addr field is aligned on a 64-bit boundary, the start of the structure will also be aligned on a 64-bit boundary. This is done for optimum performance on 64-bit architectures.
The sin6_scope_id field is a 32-bit integer that identifies a set of interfaces as appropriate for the scope [2] of the address carried in the sin6_addr field. The mapping of sin6_scope_id to an interface or set of interfaces is left to implementation and future specifications on the subject of scoped addresses.
Notice that the sockaddr_in6 structure will normally be larger than the generic sockaddr structure. On many existing implementations the sizeof(struct sockaddr_in) equals sizeof(struct sockaddr), with both being 16 bytes. Any existing code that makes this assumption needs to be examined carefully when converting to IPv6.