SOCKOPT(9) | Kernel Developer's Manual | SOCKOPT(9) |
sockopt_init
, sockopt_destroy
,
sockopt_get
, sockopt_getint
,
sockopt_set
, sockopt_setint
—
#include <sys/socketvar.h>
void
sockopt_init
(struct
sockopt *sopt, int
level, int name,
size_t size);
void
sockopt_destroy
(struct
sockopt *sopt);
int
sockopt_get
(struct
sockopt *sopt, void
*value, size_t
size);
int
sockopt_getint
(struct
sockopt *sopt, int
*value);
int
sockopt_set
(struct
sockopt *sopt, const void
*value, size_t
size);
int
sockopt_setint
(struct
sockopt *sopt, int
value);
struct sockopt { int sopt_level; /* option level */ int sopt_name; /* option name */ size_t sopt_size; /* data length */ size_t sopt_retsize; /* returned data length */ void * sopt_data; /* data pointer */ uint8_t sopt_buf[sizeof(int)]; /* internal storage */ };
The internal storage is used for the common case of values up to integer size so that memory allocation is not required and sopt_data will point to this in that case.
Rather than provide accessor functions, the sockopt structure is public and the contents are expected to be internally consistent, but the normal practice would be to use the appropriate methods for storage and retrieval of values where a known datatype is expected, as the size will be verified.
Note: a sockopt structure may only be used for a single level/name/size combination. If the structure is to be re-used, it must be destroyed and re-initialized with the new values.
options DIAGNOSTIC
DIAGNOSTIC
option will
perform basic sanity checks on socket options operations.sockopt_init
(sopt,
level, name,
size)sockopt_init
() will arrange for sopt_data to point
to a buffer of size bytes for the sockopt value.
Where memory needs to be allocated to satisfy this,
sockopt_init
() may sleep.sockopt_destroy
(sopt)sockopt_get
(sopt,
value, size)EINVAL
if an
incorrect data size is given.sockopt_getint
(sopt,
value)EINVAL
if sockopt does not contain an integer
sized value.sockopt_set
(sopt,
value, size)KM_NOSLEEP
flag which may cause
sockopt_set
() to return
ENOMEM
.
Note: If you need to use sockopt_set
()
in a context where memory allocation may be required and you do not wish
to contemplate failure, the sockopt structure can be initialised in a
more suitable context using sockopt_init
() which
will not fail.
sockopt_setint
(sopt,
value)January 3, 2018 | NetBSD 9.0 |