freebsd-dev/share/man/man9/domain.9
Bjoern A. Zeeb 3f58662dd9 The pr_destroy field does not allow us to run the teardown code in a
specific order.  VNET_SYSUNINITs however are doing exactly that.
Thus remove the VIMAGE conditional field from the domain(9) protosw
structure and replace it with VNET_SYSUNINITs.
This also allows us to change some order and to make the teardown functions
file local static.
Also convert divert(4) as it uses the same mechanism ip(4) and ip6(4) use
internally.

Slightly reshuffle the SI_SUB_* fields in kernel.h and add a new ones, e.g.,
for pfil consumers (firewalls), partially for this commit and for others
to come.

Reviewed by:		gnn, tuexen (sctp), jhb (kernel.h)
Obtained from:		projects/vnet
MFC after:		2 weeks
X-MFC:			do not remove pr_destroy
Sponsored by:		The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D6652
2016-06-01 10:14:04 +00:00

242 lines
7.0 KiB
Groff

.\"
.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
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.Dd June 1, 2016
.Dt DOMAIN 9
.Os
.Sh NAME
.Nm domain_add ,
.Nm pfctlinput ,
.Nm pfctlinput2 ,
.Nm pffinddomain ,
.Nm pffindproto ,
.Nm pffindtype ,
.Nm DOMAIN_SET
.Nd "network domain management"
.Sh SYNOPSIS
.In sys/param.h
.In sys/kernel.h
.In sys/protosw.h
.In sys/domain.h
.Ft void
.Fn domain_add "void *data"
.Ft void
.Fn pfctlinput "int cmd" "struct sockaddr *sa"
.Ft void
.Fn pfctlinput2 "int cmd" "struct sockaddr *sa" "void *ctlparam"
.Ft struct domain *
.Fn pffinddomain "int family"
.Ft struct protosw *
.Fn pffindproto "int family" "int protocol" "int type"
.Ft struct protosw *
.Fn pffindtype "int family" "int type"
.Ft void
.Fn DOMAIN_SET "name"
.Sh DESCRIPTION
Network protocols installed in the system are maintained within what
are called domains
(for example the
.Va inetdomain
and
.Va localdomain ) .
.Bd -literal
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);
void *(*dom_ifattach)(struct ifnet *);
void (*dom_ifdetach)(struct ifnet *, void *);
int (*dom_ifmtu)(struct ifnet *);
/* af-dependent data on ifnet */
};
.Ed
.Pp
Each domain contains an array of protocol switch structures
.Pq Vt "struct protosw *" ,
one for each socket type supported.
.Bd -literal
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_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; /* user-protocol hook */
};
.Ed
.Pp
The following functions handle the registration of a new domain,
lookups of specific protocols and protocol types within those domains,
and handle control messages from the system.
.Pp
.Fn 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
.Tn ICMP
message types.
When called,
.Fn pfctlinput
calls the protocol specific
.Fn pr_ctlinput
function for each protocol in that has defined one, in every domain.
.Pp
.Fn pfctlinput2
provides that same functionality of
.Fn pfctlinput ,
but with a few additional checks and a new
.Vt "void *"
argument that is passed directly to the protocol's
.Fn pr_ctlinput
function.
Unlike
.Fn pfctlinput ,
.Fn pfctlinput2
verifies that
.Fa sa
is not
.Dv NULL ,
and that only the protocol families that are the same as
.Fa sa
have their
.Fn pr_ctlinput
function called.
.Pp
.Fn domain_add
adds a new protocol domain to the system.
The argument
.Fa data
is cast directly to
.Vt "struct domain *"
within the function, but is declared
.Vt "void *"
in order to prevent compiler warnings when new domains are registered with
.Fn SYSINIT .
In most cases
.Fn domain_add
is not called directly, instead
.Fn DOMAIN_SET
is used.
.Pp
If the new domain has defined an initialization routine, it is called by
.Fn domain_add ;
as well, each of the protocols within the domain that have defined an
initialization routine will have theirs called.
.Pp
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.
.Pp
.Fn pffinddomain
finds a domain by family.
If the domain cannot be found,
.Dv NULL
is returned.
.Pp
.Fn pffindtype
and
.Fn pffindproto
look up a protocol by its number or by its type.
In most cases, if the protocol or type cannot be found,
.Dv NULL
is returned, but
.Fn pffindproto
may return the default if the requested type is
.Dv SOCK_RAW ,
a protocol switch type of
.Dv SOCK_RAW
is found, and the domain has a default raw protocol.
.Pp
Both functions are called by
.Fn socreate
in order to resolve the protocol for the socket currently being created.
.Pp
.Fn DOMAIN_SET
is a macro that simplifies the registration of a domain via
.Fn SYSINIT .
The code resulting from the macro expects there to be a domain structure
named
.Dq Fa name Ns Li domain
where
.Fa name
is the argument to
.Fn DOMAIN_SET :
.Bd -literal
struct domain localdomain =
{ AF_LOCAL, "local", unp_init, unp_externalize, unp_dispose,
localsw, &localsw[sizeof(localsw)/sizeof(localsw[0])] };
DOMAIN_SET(local);
.Ed
.Sh RETURN VALUES
Both
.Fn pffindtype
and
.Fn pffindproto
return a
.Vt "struct protosw *"
for the protocol requested.
If the protocol or socket type is not found,
.Dv NULL
is returned.
In the case of
.Fn pffindproto ,
the default protocol may be returned for
.Dv SOCK_RAW
types if the domain has a default raw protocol.
.Sh SEE ALSO
.Xr socket 2
.Sh AUTHORS
This manual page was written by
.An Chad David Aq Mt davidc@acns.ab.ca .