244 lines
7.1 KiB
Groff
244 lines
7.1 KiB
Groff
.\"
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.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice(s), this list of conditions and the following disclaimer as
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.\" the first lines of this file unmodified other than the possible
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.\" addition of one or more copyright notices.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice(s), this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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.\" DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
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.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
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.\" DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd December 7, 2012
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.Dt DOMAIN 9
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.Os
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.Sh NAME
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.Nm domain_add ,
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.Nm pfctlinput ,
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.Nm pfctlinput2 ,
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.Nm pffinddomain ,
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.Nm pffindproto ,
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.Nm pffindtype ,
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.Nm DOMAIN_SET
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.Nd "network domain management"
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.Sh SYNOPSIS
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.In sys/param.h
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.In sys/kernel.h
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.In sys/protosw.h
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.In sys/domain.h
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.Ft void
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.Fn domain_add "void *data"
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.Ft void
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.Fn pfctlinput "int cmd" "struct sockaddr *sa"
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.Ft void
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.Fn pfctlinput2 "int cmd" "struct sockaddr *sa" "void *ctlparam"
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.Ft struct domain *
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.Fn pffinddomain "int family"
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.Ft struct protosw *
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.Fn pffindproto "int family" "int protocol" "int type"
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.Ft struct protosw *
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.Fn pffindtype "int family" "int type"
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.Ft void
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.Fn DOMAIN_SET "name"
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.Sh DESCRIPTION
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Network protocols installed in the system are maintained within what
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are called domains
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(for example the
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.Va inetdomain
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and
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.Va localdomain ) .
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.Bd -literal
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struct domain {
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int dom_family; /* AF_xxx */
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char *dom_name;
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void (*dom_init) /* initialize domain data structures */
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(void);
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void (*dom_destroy) /* cleanup structures / state */
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(void);
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int (*dom_externalize) /* externalize access rights */
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(struct mbuf *, struct mbuf **);
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void (*dom_dispose) /* dispose of internalized rights */
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(struct mbuf *);
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struct protosw *dom_protosw, *dom_protoswNPROTOSW;
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struct domain *dom_next;
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int (*dom_rtattach) /* initialize routing table */
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(void **, int);
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int (*dom_rtdetach) /* clean up routing table */
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(void **, int);
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int dom_rtoffset; /* an arg to rtattach, in bits */
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int dom_maxrtkey; /* for routing layer */
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void *(*dom_ifattach)(struct ifnet *);
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void (*dom_ifdetach)(struct ifnet *, void *);
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/* af-dependent data on ifnet */
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};
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.Ed
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.Pp
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Each domain contains an array of protocol switch structures
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.Pq Vt "struct protosw *" ,
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one for each socket type supported.
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.Bd -literal
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struct protosw {
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short pr_type; /* socket type used for */
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struct domain *pr_domain; /* domain protocol a member of */
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short pr_protocol; /* protocol number */
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short pr_flags; /* see below */
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/* protocol-protocol hooks */
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pr_input_t *pr_input; /* input to protocol (from below) */
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pr_output_t *pr_output; /* output to protocol (from above) */
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pr_ctlinput_t *pr_ctlinput; /* control input (from below) */
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pr_ctloutput_t *pr_ctloutput; /* control output (from above) */
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/* utility hooks */
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pr_init_t *pr_init;
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pr_destroy_t *pr_destroy;
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pr_fasttimo_t *pr_fasttimo; /* fast timeout (200ms) */
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pr_slowtimo_t *pr_slowtimo; /* slow timeout (500ms) */
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pr_drain_t *pr_drain; /* flush any excess space possible */
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struct pr_usrreqs *pr_usrreqs; /* user-protocol hook */
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};
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.Ed
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.Pp
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The following functions handle the registration of a new domain,
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lookups of specific protocols and protocol types within those domains,
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and handle control messages from the system.
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.Pp
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.Fn pfctlinput
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is called by the system whenever an event occurs that could affect every
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domain.
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Examples of those types of events are routing table changes, interface
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shutdowns or certain
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.Tn ICMP
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message types.
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When called,
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.Fn pfctlinput
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calls the protocol specific
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.Fn pr_ctlinput
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function for each protocol in that has defined one, in every domain.
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.Pp
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.Fn pfctlinput2
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provides that same functionality of
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.Fn pfctlinput ,
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but with a few additional checks and a new
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.Vt "void *"
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argument that is passed directly to the protocol's
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.Fn pr_ctlinput
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function.
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Unlike
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.Fn pfctlinput ,
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.Fn pfctlinput2
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verifies that
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.Fa sa
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is not
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.Dv NULL ,
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and that only the protocol families that are the same as
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.Fa sa
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have their
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.Fn pr_ctlinput
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function called.
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.Pp
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.Fn domain_add
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adds a new protocol domain to the system.
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The argument
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.Fa data
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is cast directly to
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.Vt "struct domain *"
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within the function, but is declared
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.Vt "void *"
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in order to prevent compiler warnings when new domains are registered with
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.Fn SYSINIT .
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In most cases
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.Fn domain_add
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is not called directly, instead
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.Fn DOMAIN_SET
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is used.
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.Pp
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If the new domain has defined an initialization routine, it is called by
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.Fn domain_add ;
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as well, each of the protocols within the domain that have defined an
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initialization routine will have theirs called.
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.Pp
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Once a domain is added it cannot be unloaded.
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This is because there is
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no reference counting system in place to determine if there are any
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active references from sockets within that domain.
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.Pp
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.Fn pffinddomain
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finds a domain by family.
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If the domain cannot be found,
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.Dv NULL
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is returned.
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.Pp
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.Fn pffindtype
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and
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.Fn pffindproto
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look up a protocol by its number or by its type.
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In most cases, if the protocol or type cannot be found,
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.Dv NULL
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is returned, but
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.Fn pffindproto
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may return the default if the requested type is
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.Dv SOCK_RAW ,
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a protocol switch type of
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.Dv SOCK_RAW
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is found, and the domain has a default raw protocol.
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.Pp
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Both functions are called by
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.Fn socreate
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in order to resolve the protocol for the socket currently being created.
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.Pp
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.Fn DOMAIN_SET
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is a macro that simplifies the registration of a domain via
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.Fn SYSINIT .
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The code resulting from the macro expects there to be a domain structure
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named
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.Dq Fa name Ns Li domain
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where
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.Fa name
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is the argument to
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.Fn DOMAIN_SET :
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.Bd -literal
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struct domain localdomain =
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{ AF_LOCAL, "local", unp_init, unp_externalize, unp_dispose,
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localsw, &localsw[sizeof(localsw)/sizeof(localsw[0])] };
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DOMAIN_SET(local);
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.Ed
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.Sh RETURN VALUES
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Both
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.Fn pffindtype
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and
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.Fn pffindproto
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return a
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.Vt "struct protosw *"
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for the protocol requested.
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If the protocol or socket type is not found,
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.Dv NULL
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is returned.
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In the case of
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.Fn pffindproto ,
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the default protocol may be returned for
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.Dv SOCK_RAW
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types if the domain has a default raw protocol.
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.Sh SEE ALSO
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.Xr socket 2
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.Sh AUTHORS
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This manual page was written by
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.An Chad David Aq Mt davidc@acns.ab.ca .
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