Sockets Library Functions inet6opt(3SOCKET)
NAME
inet6opt, inet6optinit, inet6optappend,
inet6optfinish, inet6optsetval, inet6optnext,
inet6optfind, inet6optgetval - Option manipulation
mechanism
SYNOPSIS
cc [ flag ... ] file ... -lsocket [library...]
#include
int inet6optinit(void *extbuf, socklent extlen);
int inet6optappend(void *extbuf, socklent extlen,
int offset, uint8t type, socklent len, uintt align,
void **databufp);
int inet6optfinish(void *extbuf, socklent extlen,
int offset);
int inet6optsetval(void *databuf, int offset,
void *val, socklent vallen);
int inet6optnext(void *extbuf, socklent extlen,
int offset, uint8t *typep, socklent *lenp,
void **databufp);
int inet6optfind(void *extbuf, socklent extlen, int offset,
uint8t type, socklent *lenp, void **databufp);
intinet6optgetval(void *databuf, int offset,
void *val, socklent *vallen);
DESCRIPTION
The inet6opt functions enable users to manipulate options
without having to know the structure of the option header.
The inet6optinit() function returns the number of bytes
needed for the empty extension header, that is, without any
options. If extbuf is not NUL, it also initializes the
extension header to the correct length field. If the extlen
value is not a positive non-zero multiple of 8, the function
fails and returns -1.
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Sockets Library Functions inet6opt(3SOCKET)
The inet6optappend() function returns the updated total
length while adding an option with length len and alignment
align. If extbuf is not NUL, then, in addition to returning
the length, the function inserts any needed Pad option, ini-
tializes the option setting the type and length fields, and
returns a pointer to the location for the option content in
databufp. If the option does not fit in the extension header
buffer, the function returns -1. The type is the 8-bit
option type. The len is the length of the option data,
excluding the option type and option length fields. Once
inet6optappend() is called, the application can use the
databuf directly, or inet6optsetval() can be used to
specify the content of the option. The option type must have
a value from 2 to 255, inclusive. The values 0 and 1 are
reserved for the Pad1 and PadN options, respectively. The
option data length must have a value between 0 and 255,
inclusive, and it is the length of the option data that fol-
lows. The align parameter must have a value of 1, 2, 4, or
8. The align value cannot exceed the value of len.
The inet6optfinish() function returns the updated total
length the takes into account the final padding of the
extension header to make it a multiple of 8 bytes. If extbuf
is not NUL, the function also initializes the option by
inserting a Pad1 or PadN option of the proper length. If the
necessary pad does not fit in the extension header buffer,
the function returns -1.
The inet6optsetval() function inserts data items of vari-
ous sizes in the data portion of the option. The val parame-
ter should point to the data to be inserted. The offset
specifies the data portion of the option in which the value
should be inserted. The first byte after the option type and
length is accessed by specifying an offset of zero.
The inet6optnext() function parses the received option
extension headers which return the next option. The extbuf
and extlen parameters specify the extension header. The
offset should be zero for the first option or the length
returned by a previous call to either inet6optnext() or
inet6optfind(). The offset specifies where to continue
scanning the extension buffer. The subsequent option is
returned by updating typep, lenp, and databufp. The typep
argument stores the option type. The lenp argument stores
the length of the option data, excluding the option type and
option length fields. The databufp argument points to the
data field of the option.
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Sockets Library Functions inet6opt(3SOCKET)
The inet6optfind() function is similar to the
inet6optnext() function. Unlike inet6optnext(), the
inet6optfind() function enables the caller to specify the
option type to be searched for, rather than returning the
next option in the extension header.
The inet6optgetval() function extracts data items of
various sizes in the portion of the option. The val argument
should point to the destination for the extracted data. The
offset specifies at which point in the option's data portion
the value should be extracted. The first byte following the
option type and length is accessed by specifying an offset
of zero.
RETURN VALUES
The inet6optinit() function returns the number of bytes
needed for the empty extension header. If the extlen value
is not a positive non-zero multiple of 8, the function fails
and returns -1.
The inet6optappend() function returns the updated total
length.
The inet6optfinish() function returns the updated total
length.
The inet6optsetval() function returns the offset for the
subsequent field.
The inet6optnext() function returns the updated "previous"
length computed by advancing past the option that was
returned. When there are no additional options or if the
option extension header is malformed, the return value is
-1.
The inet6optfind() function returns the updated "previous"
total length. If an option of the specified type is not
located, the return value is -1. If the option extension
header is malformed, the return value is -1.
The inet6optgetval() function returns the offset for the
next field (that is, offset ] vallen) which can be used when
extracting option content with multiple fields.
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Sockets Library Functions inet6opt(3SOCKET)
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
ATRIBUTE TYPE ATRIBUTE VALUE
Interface Stability Standard
MT-Level Safe
SEE ALSO
RFC 3542 - Advanced Sockets Application Programming Inter-
face (API) for IPv6, The Internet Society. May 2003
SunOS 5.11 Last change: 15 Feb 2007 4
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