1.\" Copyright (c) 2001-2003 International Computer Science Institute 2.\" 3.\" Permission is hereby granted, free of charge, to any person obtaining a 4.\" copy of this software and associated documentation files (the "Software"), 5.\" to deal in the Software without restriction, including without limitation 6.\" the rights to use, copy, modify, merge, publish, distribute, sublicense, 7.\" and/or sell copies of the Software, and to permit persons to whom the 8.\" Software is furnished to do so, subject to the following conditions: 9.\" 10.\" The above copyright notice and this permission notice shall be included in 11.\" all copies or substantial portions of the Software. 12.\" 13.\" The names and trademarks of copyright holders may not be used in 14.\" advertising or publicity pertaining to the software without specific 15.\" prior permission. Title to copyright in this software and any associated 16.\" documentation will at all times remain with the copyright holders. 17.\" 18.\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 19.\" IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 20.\" FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 21.\" AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 22.\" LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 23.\" FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 24.\" DEALINGS IN THE SOFTWARE. 25.\" 26.\" $FreeBSD: src/share/man/man4/pim.4,v 1.2 2004/07/09 09:22:36 ru Exp $ 27.\" $DragonFly: src/share/man/man4/pim.4,v 1.5 2008/04/15 23:51:00 swildner Exp $ 28.\" 29.Dd April 16, 2008 30.Dt PIM 4 31.Os 32.\" 33.Sh NAME 34.Nm pim 35.Nd Protocol Independent Multicast 36.\" 37.Sh SYNOPSIS 38.Cd "options MROUTING" 39.Cd "options PIM" 40.Pp 41.In sys/types.h 42.In sys/socket.h 43.In netinet/in.h 44.In net/ip_mroute/ip_mroute.h 45.In netinet/pim.h 46.Ft int 47.Fn getsockopt "int s" IPPROTO_IP MRT_PIM "void *optval" "socklen_t *optlen" 48.Ft int 49.Fn setsockopt "int s" IPPROTO_IP MRT_PIM "const void *optval" "socklen_t optlen" 50.Ft int 51.Fn getsockopt "int s" IPPROTO_IPV6 MRT6_PIM "void *optval" "socklen_t *optlen" 52.Ft int 53.Fn setsockopt "int s" IPPROTO_IPV6 MRT6_PIM "const void *optval" "socklen_t optlen" 54.Sh DESCRIPTION 55.Tn PIM 56is the common name for two multicast routing protocols: 57Protocol Independent Multicast - Sparse Mode (PIM-SM) and 58Protocol Independent Multicast - Dense Mode (PIM-DM). 59.Pp 60PIM-SM is a multicast routing protocol that can use the underlying 61unicast routing information base or a separate multicast-capable 62routing information base. 63It builds unidirectional shared trees rooted at a Rendezvous 64Point (RP) per group, 65and optionally creates shortest-path trees per source. 66.Pp 67PIM-DM is a multicast routing protocol that uses the underlying 68unicast routing information base to flood multicast datagrams 69to all multicast routers. 70Prune messages are used to prevent future datagrams from propagating 71to routers with no group membership information. 72.Pp 73Both PIM-SM and PIM-DM are fairly complex protocols, 74though PIM-SM is much more complex. 75To enable PIM-SM or PIM-DM multicast routing in a router, 76the user must enable multicast routing and PIM processing in the kernel 77(see 78.Sx SYNOPSIS 79about the kernel configuration options), 80and must run a PIM-SM or PIM-DM capable user-level process. 81From developer's point of view, 82the programming guide described in the 83.Sx "Programming Guide" 84section should be used to control the PIM processing in the kernel. 85.\" 86.Ss Programming Guide 87After a multicast routing socket is open and multicast forwarding 88is enabled in the kernel 89(see 90.Xr multicast 4 ) , 91one of the following socket options should be used to enable or disable 92PIM processing in the kernel. 93Note that those options require certain privilege 94(i.e., root privilege): 95.Bd -literal 96/* IPv4 */ 97int v = 1; /* 1 to enable, or 0 to disable */ 98setsockopt(mrouter_s4, IPPROTO_IP, MRT_PIM, (void *)&v, sizeof(v)); 99.Ed 100.Bd -literal 101/* IPv6 */ 102int v = 1; /* 1 to enable, or 0 to disable */ 103setsockopt(mrouter_s6, IPPROTO_IPV6, MRT6_PIM, (void *)&v, sizeof(v)); 104.Ed 105.Pp 106After PIM processing is enabled, the multicast-capable interfaces 107should be added 108(see 109.Xr multicast 4 ) . 110In case of PIM-SM, the PIM-Register virtual interface must be added 111as well. 112This can be accomplished by using the following options: 113.Bd -literal 114/* IPv4 */ 115struct vifctl vc; 116memset(&vc, 0, sizeof(vc)); 117/* Assign all vifctl fields as appropriate */ 118\&... 119if (is_pim_register_vif) 120 vc.vifc_flags |= VIFF_REGISTER; 121setsockopt(mrouter_s4, IPPROTO_IP, MRT_ADD_VIF, (void *)&vc, 122 sizeof(vc)); 123.Ed 124.Bd -literal 125/* IPv6 */ 126struct mif6ctl mc; 127memset(&mc, 0, sizeof(mc)); 128/* Assign all mif6ctl fields as appropriate */ 129\&... 130if (is_pim_register_vif) 131 mc.mif6c_flags |= MIFF_REGISTER; 132setsockopt(mrouter_s6, IPPROTO_IPV6, MRT6_ADD_MIF, (void *)&mc, 133 sizeof(mc)); 134.Ed 135.Pp 136Sending or receiving of PIM packets can be accomplished by 137opening first a 138.Dq raw socket 139(see 140.Xr socket 2 ) , 141with protocol value of 142.Dv IPPROTO_PIM : 143.Bd -literal 144/* IPv4 */ 145int pim_s4; 146pim_s4 = socket(AF_INET, SOCK_RAW, IPPROTO_PIM); 147.Ed 148.Bd -literal 149/* IPv6 */ 150int pim_s6; 151pim_s6 = socket(AF_INET6, SOCK_RAW, IPPROTO_PIM); 152.Ed 153.Pp 154Then, the following system calls can be used to send or receive PIM 155packets: 156.Xr sendto 2 , 157.Xr sendmsg 2 , 158.Xr recvfrom 2 , 159.Xr recvmsg 2 . 160.\" 161.Sh SEE ALSO 162.Xr getsockopt 2 , 163.Xr recvfrom 2 , 164.Xr recvmsg 2 , 165.Xr sendmsg 2 , 166.Xr sendto 2 , 167.Xr setsockopt 2 , 168.Xr socket 2 , 169.Xr inet 4 , 170.Xr intro 4 , 171.Xr ip 4 , 172.Xr multicast 4 173.\" 174.Sh STANDARDS 175The PIM-SM protocol is specified in RFC 4601. 176The PIM-DM protocol is specified in RFC 3973. 177.\" 178.Sh AUTHORS 179.An -nosplit 180The original IPv4 PIM kernel support for IRIX and SunOS-4.x was 181implemented by 182.An Ahmed Helmy 183(USC and SGI). 184Later the code was ported to various 185.Bx 186flavors and modified by 187.An George Edmond Eddy 188(Rusty) (ISI), 189.An Hitoshi Asaeda 190(WIDE Project), and 191.An Pavlin Radoslavov 192(USC/ISI and ICSI). 193The IPv6 PIM kernel support was implemented by the KAME project 194.Pa ( http://www.kame.net ) , 195and was based on the IPv4 PIM kernel support. 196.Pp 197This manual page was written by 198.An Pavlin Radoslavov 199(ICSI). 200