1 /* 2 * Copyright (c) 1988 Stephen Deering. 3 * Copyright (c) 1992 Regents of the University of California. 4 * All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Stephen Deering of Stanford University. 8 * 9 * %sccs.include.redist.c% 10 * 11 * @(#)igmp.h 7.2 (Berkeley) 06/04/93 12 */ 13 14 /* Internet Group Management Protocol (IGMP) definitions. */ 15 16 /* 17 * IGMP packet format. 18 */ 19 struct igmp { 20 u_char igmp_type; /* version & type of IGMP message */ 21 u_char igmp_code; /* unused, should be zero */ 22 u_short igmp_cksum; /* IP-style checksum */ 23 struct in_addr igmp_group; /* group address being reported */ 24 }; /* (zero for queries) */ 25 26 #define IGMP_MINLEN 8 27 28 #define IGMP_HOST_MEMBERSHIP_QUERY 0x11 /* message types, incl. version */ 29 #define IGMP_HOST_MEMBERSHIP_REPORT 0x12 30 #define IGMP_DVMRP 0x13 /* for experimental multicast */ 31 /* routing protocol */ 32 33 #define IGMP_MAX_HOST_REPORT_DELAY 10 /* max delay for response to */ 34