SOCKADDR_IN6_LH structure (ws2ipdef.h)

Article
08/19/2022

The SOCKADDR_IN6 structure specifies a transport address and port for the AF_INET6 address family.

Syntax

typedef struct sockaddr_in6 {
  ADDRESS_FAMILY sin6_family;
  USHORT         sin6_port;
  ULONG          sin6_flowinfo;
  IN6_ADDR       sin6_addr;
  union {
    ULONG    sin6_scope_id;
    SCOPE_ID sin6_scope_struct;
  };
} SOCKADDR_IN6_LH, *PSOCKADDR_IN6_LH, *LPSOCKADDR_IN6_LH;

Members

sin6_family

The address family for the transport address. This member should always be set to AF_INET6.

sin6_port

A transport protocol port number.

sin6_flowinfo

The IPv6 flow information.

sin6_addr

An IN6_ADDR structure that contains an IPv6 transport address.

sin6_scope_id

A ULONG representation of the IPv6 scope identifier that is defined in the sin6_scope_struct member.

sin6_scope_struct

A SCOPE_ID structure that contains the scope identifier for the IPv6 transport address. The SCOPE_ID structure is defined as follows:

typedef struct {
  union {
    struct {
      ULONG  Zone : 28;
      ULONG  Level : 4;
    };
    ULONG  Value;
  };
} SCOPE_ID, *PSCOPE_ID;

Zone

The zone index that identifies the zone to which the transport address pertains. Zones of the different scopes are instantiated as follows:

Each interface on a node comprises a single zone of interface-local scope.

Each link, and the interfaces attached to that link, comprise a single zone of link-local scope.

There is a single zone of global scope that comprises all of the links and interfaces in the Internet.

The boundaries of zones of scope other than interface-local, link-local, and global are defined by network administrators.

A value of zero specifies the default zone.

Level

The scope of the IPv6 transport address. This scope must be the same as the IPv6 scope value that is embedded in the IPv6 transport address. This member can be one of the following:

ScopeLevelInterface

The transport address has interface-local scope.

ScopeLevelLink

The transport address has link-local scope.

ScopeLevelSubnet

The transport address has subnet-local scope.

ScopeLevelAdmin

The transport address has admin-local scope.

ScopeLevelSite

The transport address has site-local scope.

ScopeLevelOrganization

The transport address has organization-local scope.

ScopeLevelGlobal

The transport address has global scope.

Value

A ULONG representation of the IPv6 scope identifier.

Remarks

All of the data in the SOCKADDR_IN6 structure, except for the address family, must be specified in network-byte-order (big-endian).

The size of the SOCKADDR_IN6 structure is too large to fit in the memory space that is provided by a SOCKADDR structure. For a structure that is guaranteed to be large enough to contain a transport address for all possible address families, see SOCKADDR_STORAGE.

Requirements

Requirement	Value
Minimum supported client	Available in Windows Vista and later versions of the Windows operating systems.
Header	ws2ipdef.h (include Ws2ipdef.h)

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