int
accept_filt_add(
struct accept_filter *filt
)
int
accept_filt_del(
char *name
)
int
accept_filt_generic_mod_event(
module_t mod
, int event
, void *data
)
struct
accept_filter
*
accept_filt_get(
char *name
)
optname
of
SO_ACCEPTFILTER
.
struct accept_filter {
char accf_name[16];
void (*accf_callback)(struct socket *so, void *arg, int waitflag);
void * (*accf_create)(struct socket *so, char *arg);
void (*accf_destroy)(struct socket *so);
SLIST_ENTRY(accept_filter) accf_next; /* next on the list */
};
The module should register it with the function
accept_filt_add(),
passing a pointer to a
allocated with
malloc(9).
The accept filters currently provided with NetBSD (accf_data(9)and accf_http(9)) are implemented as pseudo-devices, but an accept filter may use any supported means of initializing and registering itself at system startup or later, including the LKM or module frameworks if they are supported by the running kernel.
The fields of are as follows:
The
accept_filt_del()
function
passed the same string used in
accept_filter.accf_name
during registration with
accept_filt_add(
),
the kernel will then disallow and further userland use of the filter.
The
accept_filt_get()
function is used internally to locate which accept filter to use via the
setsockopt(2)
system call.
The
accept_filt_generic_mod_event()
function can be used by accept filters which are loadable kernel modules
to add and delete themselves.
Alfred Perlstein, Sheldon Hearn and Jeroen Ruigrok van der Werven.
The accept filter concept was pioneered by David Filo at Yahoo! and refined to be a loadable module system by Alfred Perlstein.