Manual Pages for UNIX Operating System command usage for man inet6_opt_append

Sockets Library Functions                      inet6_opt(3SOCKET)



NAME
     inet6_opt,         inet6_opt_init,         inet6_opt_append,
     inet6_opt_finish,     inet6_opt_set_val,     inet6_opt_next,
     inet6_opt_find,  inet6_opt_get_val  -  Option   manipulation
     mechanism

SYNOPSIS
     cc [ flag ... ] file ... -lsocket [library...]
     #include 

     int inet6_opt_init(void *extbuf, socklen_t extlen);


     int inet6_opt_append(void *extbuf, socklen_t extlen,
          int offset, uint8_t type, socklen_t len, uint_t align,
          void **databufp);


     int inet6_opt_finish(void *extbuf, socklen_t extlen,
          int offset);


     int inet6_opt_set_val(void *databuf, int offset,
          void *val, socklen_t vallen);


     int inet6_opt_next(void *extbuf, socklen_t extlen,
          int offset, uint8_t *typep, socklen_t *lenp,
          void **databufp);


     int inet6_opt_find(void *extbuf, socklen_t extlen, int offset,
          uint8_t type, socklen_t *lenp, void **databufp);


     intinet6_opt_get_val(void *databuf, int offset,
          void *val, socklen_t *vallen);


DESCRIPTION
     The inet6_opt functions enable users to  manipulate  options
     without having to know the structure of the option header.


     The inet6_opt_init() function returns the  number  of  bytes
     needed  for the empty extension header, that is, without any
     options. If extbuf is not  NULL,  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                      inet6_opt(3SOCKET)



     The inet6_opt_append() function returns  the  updated  total
     length  while adding an option with length len and alignment
     align. If extbuf is not NULL, 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
     inet6_opt_append() is called, the application  can  use  the
     databuf  directly,  or  inet6_opt_set_val()  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 inet6_opt_finish() 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  NULL,  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 inet6_opt_set_val() 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 inet6_opt_next() 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  inet6_opt_next()  or
     inet6_opt_find().  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                      inet6_opt(3SOCKET)



     The   inet6_opt_find()   function   is   similar   to    the
     inet6_opt_next()   function.  Unlike  inet6_opt_next(),  the
     inet6_opt_find() function enables the caller to specify  the
     option  type  to  be searched for, rather than returning the
     next option in the extension header.


     The inet6_opt_get_val()  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 inet6_opt_init() 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 inet6_opt_append() function returns  the  updated  total
     length.


     The inet6_opt_finish() function returns  the  updated  total
     length.


     The inet6_opt_set_val() function returns the offset for  the
     subsequent field.


     The inet6_opt_next() 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 inet6_opt_find() 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 inet6_opt_get_val() 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                      inet6_opt(3SOCKET)



ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | Safe                        |
    |_____________________________|_____________________________|
    | Standard                    | See standards(5).           |
    |_____________________________|_____________________________|


SEE ALSO
     RFC 3542 - Advanced Sockets Application  Programming  Inter-
     face (API) for IPv6, The Internet Society. May 2003



































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