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DOMAIN(9) | Kernel Developer's Manual | DOMAIN(9) |
NAME¶
domain_add
,
pfctlinput
,
pfctlinput2
,
pffinddomain
,
pffindproto
,
pffindtype
,
DOMAIN_SET
—
network domain management
SYNOPSIS¶
#include
<sys/param.h>
#include
<sys/kernel.h>
#include
<sys/protosw.h>
#include
<sys/domain.h>
void
domain_add
(void
*data);
void
pfctlinput
(int
cmd, struct
sockaddr *sa);
void
pfctlinput2
(int
cmd, struct
sockaddr *sa,
void *ctlparam);
struct domain *
pffinddomain
(int
family);
struct protosw *
pffindproto
(int
family, int
protocol, int
type);
struct protosw *
pffindtype
(int
family, int
type);
void
DOMAIN_SET
(name);
DESCRIPTION¶
Network protocols installed in the system are maintained within what are called domains (for example the inetdomain and localdomain).struct domain { int dom_family; /* AF_xxx */ char *dom_name; void (*dom_init) /* initialize domain data structures */ (void); void (*dom_destroy) /* cleanup structures / state */ (void); int (*dom_externalize) /* externalize access rights */ (struct mbuf *, struct mbuf **); void (*dom_dispose) /* dispose of internalized rights */ (struct mbuf *); struct protosw *dom_protosw, *dom_protoswNPROTOSW; struct domain *dom_next; int (*dom_rtattach) /* initialize routing table */ (void **, int); int (*dom_rtdetach) /* clean up routing table */ (void **, int); int dom_rtoffset; /* an arg to rtattach, in bits */ int dom_maxrtkey; /* for routing layer */ void *(*dom_ifattach)(struct ifnet *); void (*dom_ifdetach)(struct ifnet *, void *); /* af-dependent data on ifnet */ };
struct protosw { short pr_type; /* socket type used for */ struct domain *pr_domain; /* domain protocol a member of */ short pr_protocol; /* protocol number */ short pr_flags; /* see below */ /* protocol-protocol hooks */ pr_input_t *pr_input; /* input to protocol (from below) */ pr_output_t *pr_output; /* output to protocol (from above) */ pr_ctlinput_t *pr_ctlinput; /* control input (from below) */ pr_ctloutput_t *pr_ctloutput; /* control output (from above) */ /* utility hooks */ pr_init_t *pr_init; pr_destroy_t *pr_destroy; pr_fasttimo_t *pr_fasttimo; /* fast timeout (200ms) */ pr_slowtimo_t *pr_slowtimo; /* slow timeout (500ms) */ pr_drain_t *pr_drain; /* flush any excess space possible */ struct pr_usrreqs *pr_usrreqs; /* supersedes pr_usrreq() */ };
pfctlinput
() is called by the system whenever
an event occurs that could affect every domain. Examples of those types of
events are routing table changes, interface shutdowns or certain ICMP message
types. When called, pfctlinput
() calls the
protocol specific pr_ctlinput
() function
for each protocol in that has defined one, in every domain.
pfctlinput2
() provides that same
functionality of pfctlinput
(), but with a
few additional checks and a new void *
argument that is passed directly to the protocol's
pr_ctlinput
() function. Unlike
pfctlinput
(),
pfctlinput2
() verifies that
sa is not
NULL
, and that only the protocol families
that are the same as sa have their
pr_ctlinput
() function called.
domain_add
() adds a new protocol domain to
the system. The argument data is cast
directly to struct domain * within the
function, but is declared void * in order to
prevent compiler warnings when new domains are registered with
SYSINIT
(). In most cases
domain_add
() is not called directly,
instead DOMAIN_SET
() is used.
If the new domain has defined an initialization routine, it is called by
domain_add
(); as well, each of the
protocols within the domain that have defined an initialization routine will
have theirs called.
Once a domain is added it cannot be unloaded. This is because there is no
reference counting system in place to determine if there are any active
references from sockets within that domain.
pffinddomain
() finds a domain by family. If
the domain cannot be found, NULL
is
returned.
pffindtype
() and
pffindproto
() look up a protocol by its
number or by its type. In most cases, if the protocol or type cannot be found,
NULL
is returned, but
pffindproto
() may return the default if the
requested type is SOCK_RAW
, a protocol
switch type of SOCK_RAW
is found, and the
domain has a default raw protocol.
Both functions are called by socreate
() in
order to resolve the protocol for the socket currently being created.
DOMAIN_SET
() is a macro that simplifies the
registration of a domain via SYSINIT
(). The
code resulting from the macro expects there to be a domain structure named
“namedomain
”
where name is the argument to
DOMAIN_SET
():
struct domain localdomain = { AF_LOCAL, "local", unp_init, unp_externalize, unp_dispose, localsw, &localsw[sizeof(localsw)/sizeof(localsw[0])] }; DOMAIN_SET(local);
RETURN VALUES¶
Bothpffindtype
() and
pffindproto
() return a
struct protosw * for the protocol requested.
If the protocol or socket type is not found,
NULL
is returned. In the case of
pffindproto
(), the default protocol may be
returned for SOCK_RAW
types if the domain
has a default raw protocol.
SEE ALSO¶
socket(2)AUTHORS¶
This manual page was written by Chad David ⟨davidc@acns.ab.ca⟩.December 7, 2012 | Debian |