1.\" 2.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice(s), this list of conditions and the following disclaimer as 9.\" the first lines of this file unmodified other than the possible 10.\" addition of one or more copyright notices. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice(s), this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 16.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 18.\" DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY 19.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 20.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 21.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 22.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 25.\" DAMAGE. 26.\" 27.\" $FreeBSD$ 28.\" 29.Dd April 13, 2021 30.Dt DOMAIN 9 31.Os 32.Sh NAME 33.Nm domain_add , 34.Nm pfctlinput , 35.Nm pffinddomain , 36.Nm pffindproto , 37.Nm pffindtype , 38.Nm DOMAIN_SET 39.Nd "network domain management" 40.Sh SYNOPSIS 41.In sys/param.h 42.In sys/kernel.h 43.In sys/protosw.h 44.In sys/domain.h 45.Ft void 46.Fn domain_add "void *data" 47.Ft void 48.Fn pfctlinput "int cmd" "struct sockaddr *sa" 49.Ft struct domain * 50.Fn pffinddomain "int family" 51.Ft struct protosw * 52.Fn pffindproto "int family" "int protocol" "int type" 53.Ft struct protosw * 54.Fn pffindtype "int family" "int type" 55.Ft void 56.Fn DOMAIN_SET "name" 57.Sh DESCRIPTION 58Network protocols installed in the system are maintained within what 59are called domains 60(for example the 61.Va inetdomain 62and 63.Va localdomain ) . 64.Bd -literal 65struct domain { 66 int dom_family; /* AF_xxx */ 67 char *dom_name; 68 void (*dom_init) /* initialize domain data structures */ 69 (void); 70 void (*dom_destroy) /* cleanup structures / state */ 71 (void); 72 int (*dom_externalize) /* externalize access rights */ 73 (struct mbuf *, struct mbuf **); 74 void (*dom_dispose) /* dispose of internalized rights */ 75 (struct mbuf *); 76 struct protosw *dom_protosw, *dom_protoswNPROTOSW; 77 struct domain *dom_next; 78 int (*dom_rtattach) /* initialize routing table */ 79 (void **, int); 80 int (*dom_rtdetach) /* clean up routing table */ 81 (void **, int); 82 void *(*dom_ifattach)(struct ifnet *); 83 void (*dom_ifdetach)(struct ifnet *, void *); 84 int (*dom_ifmtu)(struct ifnet *); 85 /* af-dependent data on ifnet */ 86}; 87.Ed 88.Pp 89Each domain contains an array of protocol switch structures 90.Pq Vt "struct protosw *" , 91one for each socket type supported. 92.Bd -literal 93struct protosw { 94 short pr_type; /* socket type used for */ 95 struct domain *pr_domain; /* domain protocol a member of */ 96 short pr_protocol; /* protocol number */ 97 short pr_flags; /* see below */ 98/* protocol-protocol hooks */ 99 pr_input_t *pr_input; /* input to protocol (from below) */ 100 pr_output_t *pr_output; /* output to protocol (from above) */ 101 pr_ctlinput_t *pr_ctlinput; /* control input (from below) */ 102 pr_ctloutput_t *pr_ctloutput; /* control output (from above) */ 103/* utility hooks */ 104 pr_init_t *pr_init; 105 pr_fasttimo_t *pr_fasttimo; /* fast timeout (200ms) */ 106 pr_slowtimo_t *pr_slowtimo; /* slow timeout (500ms) */ 107 pr_drain_t *pr_drain; /* flush any excess space possible */ 108 109 struct pr_usrreqs *pr_usrreqs; /* user-protocol hook */ 110}; 111.Ed 112.Pp 113The following functions handle the registration of a new domain, 114lookups of specific protocols and protocol types within those domains, 115and handle control messages from the system. 116.Pp 117.Fn pfctlinput 118is called by the system whenever an event occurs that could affect every 119domain. 120Examples of those types of events are routing table changes, interface 121shutdowns or certain 122.Tn ICMP 123message types. 124When called, 125.Fn pfctlinput 126calls the protocol specific 127.Fn pr_ctlinput 128function for each protocol in that has defined one, in every domain. 129.Pp 130.Fn domain_add 131adds a new protocol domain to the system. 132The argument 133.Fa data 134is cast directly to 135.Vt "struct domain *" 136within the function, but is declared 137.Vt "void *" 138in order to prevent compiler warnings when new domains are registered with 139.Fn SYSINIT . 140In most cases 141.Fn domain_add 142is not called directly, instead 143.Fn DOMAIN_SET 144is used. 145.Pp 146If the new domain has defined an initialization routine, it is called by 147.Fn domain_add ; 148as well, each of the protocols within the domain that have defined an 149initialization routine will have theirs called. 150.Pp 151Once a domain is added it cannot be unloaded. 152This is because there is 153no reference counting system in place to determine if there are any 154active references from sockets within that domain. 155.Pp 156.Fn pffinddomain 157finds a domain by family. 158If the domain cannot be found, 159.Dv NULL 160is returned. 161.Pp 162.Fn pffindtype 163and 164.Fn pffindproto 165look up a protocol by its number or by its type. 166In most cases, if the protocol or type cannot be found, 167.Dv NULL 168is returned, but 169.Fn pffindproto 170may return the default if the requested type is 171.Dv SOCK_RAW , 172a protocol switch type of 173.Dv SOCK_RAW 174is found, and the domain has a default raw protocol. 175.Pp 176Both functions are called by 177.Fn socreate 178in order to resolve the protocol for the socket currently being created. 179.Pp 180.Fn DOMAIN_SET 181is a macro that simplifies the registration of a domain via 182.Fn SYSINIT . 183The code resulting from the macro expects there to be a domain structure 184named 185.Dq Fa name Ns Li domain 186where 187.Fa name 188is the argument to 189.Fn DOMAIN_SET : 190.Bd -literal 191struct domain localdomain = 192{ AF_LOCAL, "local", unp_init, unp_externalize, unp_dispose, 193 localsw, &localsw[sizeof(localsw)/sizeof(localsw[0])] }; 194 195DOMAIN_SET(local); 196.Ed 197.Sh RETURN VALUES 198Both 199.Fn pffindtype 200and 201.Fn pffindproto 202return a 203.Vt "struct protosw *" 204for the protocol requested. 205If the protocol or socket type is not found, 206.Dv NULL 207is returned. 208In the case of 209.Fn pffindproto , 210the default protocol may be returned for 211.Dv SOCK_RAW 212types if the domain has a default raw protocol. 213.Sh SEE ALSO 214.Xr socket 2 215.Sh HISTORY 216The functions 217.Fn domain_add , 218.Fn pfctlinput , 219.Fn pffinddomain , 220.Fn pffindproto , 221.Fn pffindtype 222and 223.Fn DOMAIN_SET 224first appeared in 225.Fx 4.4 . 226.Sh AUTHORS 227This manual page was written by 228.An Chad David Aq Mt davidc@acns.ab.ca . 229