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 January 3, 2022 30.Dt DOMAIN 9 31.Os 32.Sh NAME 33.Nm domain_add , 34.Nm domain_init , 35.Nm pfctlinput , 36.Nm pffinddomain , 37.Nm pffindproto , 38.Nm pffindtype , 39.Nm DOMAIN_SET 40.Nd "network domain management" 41.Sh SYNOPSIS 42.In sys/param.h 43.In sys/kernel.h 44.In sys/protosw.h 45.In sys/domain.h 46.Ft void 47.Fn domain_add "void *data" 48.Ft void 49.Fn domain_init "void *data" 50.Ft void 51.Fn pfctlinput "int cmd" "struct sockaddr *sa" 52.Ft struct domain * 53.Fn pffinddomain "int family" 54.Ft struct protosw * 55.Fn pffindproto "int family" "int protocol" "int type" 56.Ft struct protosw * 57.Fn pffindtype "int family" "int type" 58.Ft void 59.Fn DOMAIN_SET "name" 60.Sh DESCRIPTION 61Network protocols installed in the system are maintained within what 62are called domains 63(for example the 64.Va inetdomain 65and 66.Va localdomain ) . 67.Bd -literal 68struct domain { 69 int dom_family; /* AF_xxx */ 70 char *dom_name; 71 int dom_flags; 72 int (*dom_probe)(void); /* check for support (optional) */ 73 int (*dom_externalize) /* externalize access rights */ 74 (struct mbuf *, struct mbuf **); 75 void (*dom_dispose) /* dispose of internalized rights */ 76 (struct mbuf *); 77 struct protosw *dom_protosw, *dom_protoswNPROTOSW; 78 struct domain *dom_next; 79 int (*dom_rtattach) /* initialize routing table */ 80 (void **, int); 81 int (*dom_rtdetach) /* clean up routing table */ 82 (void **, int); 83 void *(*dom_ifattach)(struct ifnet *); 84 void (*dom_ifdetach)(struct ifnet *, void *); 85 int (*dom_ifmtu)(struct ifnet *); 86 /* af-dependent data on ifnet */ 87}; 88.Ed 89.Pp 90Each domain contains an array of protocol switch structures 91.Pq Vt "struct protosw *" , 92one for each socket type supported. 93.Bd -literal 94struct protosw { 95 short pr_type; /* socket type used for */ 96 struct domain *pr_domain; /* domain protocol a member of */ 97 short pr_protocol; /* protocol number */ 98 short pr_flags; /* see below */ 99/* protocol-protocol hooks */ 100 pr_input_t *pr_input; /* input to protocol (from below) */ 101 pr_output_t *pr_output; /* output to protocol (from above) */ 102 pr_ctlinput_t *pr_ctlinput; /* control input (from below) */ 103 pr_ctloutput_t *pr_ctloutput; /* control output (from above) */ 104/* utility hooks */ 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 a probe routine, it is called first in 147.Fn domain_add 148to determine if the domain should be supported on the current system. 149If the probe routine returns a non-0 value, then the domain will not be 150marked as supported. 151Unsupported domains do not proceed with the initialization process and are not 152discoverable by 153.Fn pffinddomain , 154.Fn pffindtype , 155or 156.Fn pffindproto . 157.Pp 158.Fn domain_init 159is called after 160.Fn domain_add 161during boot and for each 162.Xr vnet 9 . 163If the new domain has defined an initialization routine, it is called during 164.Fn domain_init ; 165as well, each of the protocols within the domain that have defined an 166initialization routine will have theirs called. 167Note that domain initialization cannot fail at this time. 168.Pp 169Once a domain is added it cannot be completely unloaded. 170This is because there is 171no reference counting system in place to determine if there are any 172active references from sockets within that domain. 173.Pp 174.Fn pffinddomain 175finds a domain by family. 176If the domain cannot be found, 177.Dv NULL 178is returned. 179.Pp 180.Fn pffindtype 181and 182.Fn pffindproto 183look up a protocol by its number or by its type. 184In most cases, if the protocol or type cannot be found, 185.Dv NULL 186is returned, but 187.Fn pffindproto 188may return the default if the requested type is 189.Dv SOCK_RAW , 190a protocol switch type of 191.Dv SOCK_RAW 192is found, and the domain has a default raw protocol. 193.Pp 194Both functions are called by 195.Fn socreate 196in order to resolve the protocol for the socket currently being created. 197.Pp 198.Fn DOMAIN_SET 199is a macro that simplifies the registration of a domain via 200.Fn SYSINIT . 201The code resulting from the macro expects there to be a domain structure 202named 203.Dq Fa name Ns Li domain 204where 205.Fa name 206is the argument to 207.Fn DOMAIN_SET : 208.Bd -literal 209struct domain localdomain = 210{ AF_LOCAL, "local", unp_init, unp_externalize, unp_dispose, 211 localsw, &localsw[sizeof(localsw)/sizeof(localsw[0])] }; 212 213DOMAIN_SET(local); 214.Ed 215.Sh RETURN VALUES 216Both 217.Fn pffindtype 218and 219.Fn pffindproto 220return a 221.Vt "struct protosw *" 222for the protocol requested. 223If the protocol or socket type is not found, 224.Dv NULL 225is returned. 226In the case of 227.Fn pffindproto , 228the default protocol may be returned for 229.Dv SOCK_RAW 230types if the domain has a default raw protocol. 231.Sh SEE ALSO 232.Xr socket 2 233.Sh HISTORY 234The functions 235.Fn domain_add , 236.Fn pfctlinput , 237.Fn pffinddomain , 238.Fn pffindproto , 239.Fn pffindtype 240and 241.Fn DOMAIN_SET 242first appeared in 243.Fx 4.4 . 244.Sh AUTHORS 245This manual page was written by 246.An Chad David Aq Mt davidc@acns.ab.ca . 247