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 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 void (*dom_init) /* initialize domain data structures */ 73 (void); 74 int (*dom_probe)(void); /* check for support (optional) */ 75 void (*dom_destroy) /* cleanup structures / state */ 76 (void); 77 int (*dom_externalize) /* externalize access rights */ 78 (struct mbuf *, struct mbuf **); 79 void (*dom_dispose) /* dispose of internalized rights */ 80 (struct mbuf *); 81 struct protosw *dom_protosw, *dom_protoswNPROTOSW; 82 struct domain *dom_next; 83 int (*dom_rtattach) /* initialize routing table */ 84 (void **, int); 85 int (*dom_rtdetach) /* clean up routing table */ 86 (void **, int); 87 void *(*dom_ifattach)(struct ifnet *); 88 void (*dom_ifdetach)(struct ifnet *, void *); 89 int (*dom_ifmtu)(struct ifnet *); 90 /* af-dependent data on ifnet */ 91}; 92.Ed 93.Pp 94Each domain contains an array of protocol switch structures 95.Pq Vt "struct protosw *" , 96one for each socket type supported. 97.Bd -literal 98struct protosw { 99 short pr_type; /* socket type used for */ 100 struct domain *pr_domain; /* domain protocol a member of */ 101 short pr_protocol; /* protocol number */ 102 short pr_flags; /* see below */ 103/* protocol-protocol hooks */ 104 pr_input_t *pr_input; /* input to protocol (from below) */ 105 pr_output_t *pr_output; /* output to protocol (from above) */ 106 pr_ctlinput_t *pr_ctlinput; /* control input (from below) */ 107 pr_ctloutput_t *pr_ctloutput; /* control output (from above) */ 108/* utility hooks */ 109 pr_init_t *pr_init; 110 pr_fasttimo_t *pr_fasttimo; /* fast timeout (200ms) */ 111 pr_slowtimo_t *pr_slowtimo; /* slow timeout (500ms) */ 112 pr_drain_t *pr_drain; /* flush any excess space possible */ 113 114 struct pr_usrreqs *pr_usrreqs; /* user-protocol hook */ 115}; 116.Ed 117.Pp 118The following functions handle the registration of a new domain, 119lookups of specific protocols and protocol types within those domains, 120and handle control messages from the system. 121.Pp 122.Fn pfctlinput 123is called by the system whenever an event occurs that could affect every 124domain. 125Examples of those types of events are routing table changes, interface 126shutdowns or certain 127.Tn ICMP 128message types. 129When called, 130.Fn pfctlinput 131calls the protocol specific 132.Fn pr_ctlinput 133function for each protocol in that has defined one, in every domain. 134.Pp 135.Fn domain_add 136adds a new protocol domain to the system. 137The argument 138.Fa data 139is cast directly to 140.Vt "struct domain *" 141within the function, but is declared 142.Vt "void *" 143in order to prevent compiler warnings when new domains are registered with 144.Fn SYSINIT . 145In most cases 146.Fn domain_add 147is not called directly, instead 148.Fn DOMAIN_SET 149is used. 150.Pp 151If the new domain has defined a probe routine, it is called first in 152.Fn domain_add 153to determine if the domain should be supported on the current system. 154If the probe routine returns a non-0 value, then the domain will not be 155marked as supported. 156Unsupported domains do not proceed with the initialization process and are not 157discoverable by 158.Fn pffinddomain , 159.Fn pffindtype , 160or 161.Fn pffindproto . 162.Pp 163.Fn domain_init 164is called after 165.Fn domain_add 166during boot and for each 167.Xr vnet 9 . 168If the new domain has defined an initialization routine, it is called during 169.Fn domain_init ; 170as well, each of the protocols within the domain that have defined an 171initialization routine will have theirs called. 172Note that domain initialization cannot fail at this time. 173.Pp 174Once a domain is added it cannot be completely unloaded. 175This is because there is 176no reference counting system in place to determine if there are any 177active references from sockets within that domain. 178If the domain defines a 179.Fn dom_destroy 180routine, then it will be invoked during vnet teardown. 181.Pp 182.Fn pffinddomain 183finds a domain by family. 184If the domain cannot be found, 185.Dv NULL 186is returned. 187.Pp 188.Fn pffindtype 189and 190.Fn pffindproto 191look up a protocol by its number or by its type. 192In most cases, if the protocol or type cannot be found, 193.Dv NULL 194is returned, but 195.Fn pffindproto 196may return the default if the requested type is 197.Dv SOCK_RAW , 198a protocol switch type of 199.Dv SOCK_RAW 200is found, and the domain has a default raw protocol. 201.Pp 202Both functions are called by 203.Fn socreate 204in order to resolve the protocol for the socket currently being created. 205.Pp 206.Fn DOMAIN_SET 207is a macro that simplifies the registration of a domain via 208.Fn SYSINIT . 209The code resulting from the macro expects there to be a domain structure 210named 211.Dq Fa name Ns Li domain 212where 213.Fa name 214is the argument to 215.Fn DOMAIN_SET : 216.Bd -literal 217struct domain localdomain = 218{ AF_LOCAL, "local", unp_init, unp_externalize, unp_dispose, 219 localsw, &localsw[sizeof(localsw)/sizeof(localsw[0])] }; 220 221DOMAIN_SET(local); 222.Ed 223.Sh RETURN VALUES 224Both 225.Fn pffindtype 226and 227.Fn pffindproto 228return a 229.Vt "struct protosw *" 230for the protocol requested. 231If the protocol or socket type is not found, 232.Dv NULL 233is returned. 234In the case of 235.Fn pffindproto , 236the default protocol may be returned for 237.Dv SOCK_RAW 238types if the domain has a default raw protocol. 239.Sh SEE ALSO 240.Xr socket 2 241.Sh HISTORY 242The functions 243.Fn domain_add , 244.Fn pfctlinput , 245.Fn pffinddomain , 246.Fn pffindproto , 247.Fn pffindtype 248and 249.Fn DOMAIN_SET 250first appeared in 251.Fx 4.4 . 252.Sh AUTHORS 253This manual page was written by 254.An Chad David Aq Mt davidc@acns.ab.ca . 255