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 December 27, 2021 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 void (*dom_destroy) /* cleanup structures / state */ 74 (void); 75 int (*dom_externalize) /* externalize access rights */ 76 (struct mbuf *, struct mbuf **); 77 void (*dom_dispose) /* dispose of internalized rights */ 78 (struct mbuf *); 79 struct protosw *dom_protosw, *dom_protoswNPROTOSW; 80 struct domain *dom_next; 81 int (*dom_rtattach) /* initialize routing table */ 82 (void **, int); 83 int (*dom_rtdetach) /* clean up routing table */ 84 (void **, int); 85 void *(*dom_ifattach)(struct ifnet *); 86 void (*dom_ifdetach)(struct ifnet *, void *); 87 int (*dom_ifmtu)(struct ifnet *); 88 /* af-dependent data on ifnet */ 89}; 90.Ed 91.Pp 92Each domain contains an array of protocol switch structures 93.Pq Vt "struct protosw *" , 94one for each socket type supported. 95.Bd -literal 96struct protosw { 97 short pr_type; /* socket type used for */ 98 struct domain *pr_domain; /* domain protocol a member of */ 99 short pr_protocol; /* protocol number */ 100 short pr_flags; /* see below */ 101/* protocol-protocol hooks */ 102 pr_input_t *pr_input; /* input to protocol (from below) */ 103 pr_output_t *pr_output; /* output to protocol (from above) */ 104 pr_ctlinput_t *pr_ctlinput; /* control input (from below) */ 105 pr_ctloutput_t *pr_ctloutput; /* control output (from above) */ 106/* utility hooks */ 107 pr_fasttimo_t *pr_fasttimo; /* fast timeout (200ms) */ 108 pr_slowtimo_t *pr_slowtimo; /* slow timeout (500ms) */ 109 pr_drain_t *pr_drain; /* flush any excess space possible */ 110 111 struct pr_usrreqs *pr_usrreqs; /* user-protocol hook */ 112}; 113.Ed 114.Pp 115The following functions handle the registration of a new domain, 116lookups of specific protocols and protocol types within those domains, 117and handle control messages from the system. 118.Pp 119.Fn pfctlinput 120is called by the system whenever an event occurs that could affect every 121domain. 122Examples of those types of events are routing table changes, interface 123shutdowns or certain 124.Tn ICMP 125message types. 126When called, 127.Fn pfctlinput 128calls the protocol specific 129.Fn pr_ctlinput 130function for each protocol in that has defined one, in every domain. 131.Pp 132.Fn domain_add 133adds a new protocol domain to the system. 134The argument 135.Fa data 136is cast directly to 137.Vt "struct domain *" 138within the function, but is declared 139.Vt "void *" 140in order to prevent compiler warnings when new domains are registered with 141.Fn SYSINIT . 142In most cases 143.Fn domain_add 144is not called directly, instead 145.Fn DOMAIN_SET 146is used. 147.Pp 148If the new domain has defined a probe routine, it is called first in 149.Fn domain_add 150to determine if the domain should be supported on the current system. 151If the probe routine returns a non-0 value, then the domain will not be 152marked as supported. 153Unsupported domains do not proceed with the initialization process and are not 154discoverable by 155.Fn pffinddomain , 156.Fn pffindtype , 157or 158.Fn pffindproto . 159.Pp 160.Fn domain_init 161is called after 162.Fn domain_add 163during boot and for each 164.Xr vnet 9 . 165If the new domain has defined an initialization routine, it is called during 166.Fn domain_init ; 167as well, each of the protocols within the domain that have defined an 168initialization routine will have theirs called. 169Note that domain initialization cannot fail at this time. 170.Pp 171Once a domain is added it cannot be completely unloaded. 172This is because there is 173no reference counting system in place to determine if there are any 174active references from sockets within that domain. 175If the domain defines a 176.Fn dom_destroy 177routine, then it will be invoked during vnet teardown. 178.Pp 179.Fn pffinddomain 180finds a domain by family. 181If the domain cannot be found, 182.Dv NULL 183is returned. 184.Pp 185.Fn pffindtype 186and 187.Fn pffindproto 188look up a protocol by its number or by its type. 189In most cases, if the protocol or type cannot be found, 190.Dv NULL 191is returned, but 192.Fn pffindproto 193may return the default if the requested type is 194.Dv SOCK_RAW , 195a protocol switch type of 196.Dv SOCK_RAW 197is found, and the domain has a default raw protocol. 198.Pp 199Both functions are called by 200.Fn socreate 201in order to resolve the protocol for the socket currently being created. 202.Pp 203.Fn DOMAIN_SET 204is a macro that simplifies the registration of a domain via 205.Fn SYSINIT . 206The code resulting from the macro expects there to be a domain structure 207named 208.Dq Fa name Ns Li domain 209where 210.Fa name 211is the argument to 212.Fn DOMAIN_SET : 213.Bd -literal 214struct domain localdomain = 215{ AF_LOCAL, "local", unp_init, unp_externalize, unp_dispose, 216 localsw, &localsw[sizeof(localsw)/sizeof(localsw[0])] }; 217 218DOMAIN_SET(local); 219.Ed 220.Sh RETURN VALUES 221Both 222.Fn pffindtype 223and 224.Fn pffindproto 225return a 226.Vt "struct protosw *" 227for the protocol requested. 228If the protocol or socket type is not found, 229.Dv NULL 230is returned. 231In the case of 232.Fn pffindproto , 233the default protocol may be returned for 234.Dv SOCK_RAW 235types if the domain has a default raw protocol. 236.Sh SEE ALSO 237.Xr socket 2 238.Sh HISTORY 239The functions 240.Fn domain_add , 241.Fn pfctlinput , 242.Fn pffinddomain , 243.Fn pffindproto , 244.Fn pffindtype 245and 246.Fn DOMAIN_SET 247first appeared in 248.Fx 4.4 . 249.Sh AUTHORS 250This manual page was written by 251.An Chad David Aq Mt davidc@acns.ab.ca . 252