1 /* $NetBSD: dvmrp.h,v 1.7 2003/03/05 21:05:39 wiz Exp $ */ 2 3 /* 4 * The mrouted program is covered by the license in the accompanying file 5 * named "LICENSE". Use of the mrouted program represents acceptance of 6 * the terms and conditions listed in that file. 7 * 8 * The mrouted program is COPYRIGHT 1989 by The Board of Trustees of 9 * Leland Stanford Junior University. 10 */ 11 12 /* 13 * A DVMRP message consists of an IP header + an IGMP header + (for some types) 14 * zero or more bytes of data. 15 * 16 * For REPORT messages, the data is route information; the route information 17 * consists of one or more lists of the following form: 18 * 19 * (mask, (origin, metric), (origin, metric), ...) 20 * 21 * where: 22 * 23 * "mask" is the subnet mask for all the origins in the list. 24 * It is always THREE bytes long, containing the low-order 25 * three bytes of the mask (the high-order byte is always 26 * 0xff and therefore need not be transmitted). 27 * 28 * "origin" is the number of a subnet from which multicast datagrams 29 * may originate. It is from one to four bytes long, 30 * depending on the value of "mask": 31 * if all bytes of the mask are zero 32 * the subnet number is one byte long 33 * else if the low-order two bytes of the mask are zero 34 * the subnet number is two bytes long 35 * else if the lowest-order byte of the mask is zero 36 * the subnet number is three bytes long, 37 * else 38 * the subnet number is four bytes long. 39 * 40 * "metric" is a one-byte value consisting of two subfields: 41 * - the high-order bit is a flag which, when set, indicates 42 * the last (origin, metric) pair of a list. 43 * - the low-order seven bits contain the routing metric for 44 * the corresponding origin, relative to the sender of the 45 * DVMRP report. The metric may have the value of UNREACHABLE 46 * added to it as a "split horizon" indication (so called 47 * "poisoned reverse"). 48 * 49 * Within a list, the origin subnet numbers must be in ascending order, and 50 * the lists themselves are in order of increasing mask value. A message may 51 * not exceed 576 bytes, the default maximum IP reassembly size, including 52 * the IP and IGMP headers; the route information may be split across more 53 * than one message if necessary, by terminating a list in one message and 54 * starting a new list in the next message (repeating the same mask value, 55 * if necessary). 56 * 57 * For NEIGHBORS messages, the data is neighboring-router information 58 * consisting of one or more lists of the following form: 59 * 60 * (local-addr, metric, threshold, ncount, neighbor, neighbor, ...) 61 * 62 * where: 63 * 64 * "local-addr" is the sending router's address as seen by the neighbors 65 * in this list; it is always four bytes long. 66 * "metric" is a one-byte unsigned value, the TTL `cost' of forwarding 67 * packets to any of the neighbors on this list. 68 * "threshold" is a one-byte unsigned value, a lower bound on the TTL a 69 * packet must have to be forwarded to any of the neighbors on 70 * this list. 71 * "ncount" is the number of neighbors in this list. 72 * "neighbor" is the address of a neighboring router, four bytes long. 73 * 74 * As with REPORT messages, NEIGHBORS messages should not exceed 576 bytes, 75 * including the IP and IGMP headers; split longer messages by terminating the 76 * list in one and continuing in another, repeating the local-addr, etc., if 77 * necessary. 78 * 79 * For NEIGHBORS2 messages, the data is identical to NEIGHBORS except 80 * there is a flags byte before the neighbor count: 81 * 82 * (local-addr, metric, threshold, flags, ncount, neighbor, neighbor, ...) 83 */ 84 85 /* 86 * DVMRP message types (carried in the "code" field of an IGMP header) 87 */ 88 #define DVMRP_PROBE 1 /* for finding neighbors */ 89 #define DVMRP_REPORT 2 /* for reporting some or all routes */ 90 #define DVMRP_ASK_NEIGHBORS 3 /* sent by mapper, asking for a list */ 91 /* of this router's neighbors. */ 92 #define DVMRP_NEIGHBORS 4 /* response to such a request */ 93 #define DVMRP_ASK_NEIGHBORS2 5 /* as above, want new format reply */ 94 #define DVMRP_NEIGHBORS2 6 95 #define DVMRP_PRUNE 7 /* prune message */ 96 #define DVMRP_GRAFT 8 /* graft message */ 97 #define DVMRP_GRAFT_ACK 9 /* graft acknowledgement */ 98 #define DVMRP_INFO_REQUEST 10 /* information request */ 99 #define DVMRP_INFO_REPLY 11 /* information reply */ 100 101 /* 102 * 'flags' byte values in DVMRP_NEIGHBORS2 reply. 103 */ 104 #define DVMRP_NF_TUNNEL 0x01 /* neighbors reached via tunnel */ 105 #define DVMRP_NF_SRCRT 0x02 /* tunnel uses IP source routing */ 106 #define DVMRP_NF_PIM 0x04 /* neighbor is a PIM neighbor */ 107 #define DVMRP_NF_DOWN 0x10 /* kernel state of interface */ 108 #define DVMRP_NF_DISABLED 0x20 /* administratively disabled */ 109 #define DVMRP_NF_QUERIER 0x40 /* I am the subnet's querier */ 110 #define DVMRP_NF_LEAF 0x80 /* Neighbor reports that it is a leaf */ 111 112 /* 113 * Request/reply types for info queries/replies 114 */ 115 #define DVMRP_INFO_VERSION 1 /* version string */ 116 #define DVMRP_INFO_NEIGHBORS 2 /* neighbors2 data */ 117 118 /* 119 * Limit on length of route data 120 */ 121 #define MAX_IP_PACKET_LEN 576 122 #define MIN_IP_HEADER_LEN 20 123 #define MAX_IP_HEADER_LEN 60 124 #define MAX_DVMRP_DATA_LEN \ 125 ( MAX_IP_PACKET_LEN - MAX_IP_HEADER_LEN - IGMP_MINLEN ) 126 127 /* 128 * Various protocol constants (all times in seconds) 129 */ 130 /* address for multicast DVMRP msgs */ 131 #define INADDR_DVMRP_GROUP (u_int32_t)0xe0000004 /* 224.0.0.4 */ 132 /* 133 * The IGMPv2 <netinet/in.h> defines INADDR_ALLRTRS_GROUP, but earlier 134 * ones don't, so we define it conditionally here. 135 */ 136 #ifndef INADDR_ALLRTRS_GROUP 137 /* address for multicast mtrace msg */ 138 #define INADDR_ALLRTRS_GROUP (u_int32_t)0xe0000002 /* 224.0.0.2 */ 139 #endif 140 141 #define ROUTE_MAX_REPORT_DELAY 5 /* max delay for reporting changes */ 142 /* (This is the timer interrupt */ 143 /* interval; all times must be */ 144 /* multiples of this value.) */ 145 146 #define ROUTE_REPORT_INTERVAL 60 /* periodic route report interval */ 147 #define ROUTE_SWITCH_TIME 140 /* time to switch to equivalent gw */ 148 #define ROUTE_EXPIRE_TIME 200 /* time to mark route invalid */ 149 #define ROUTE_DISCARD_TIME 340 /* time to garbage collect route */ 150 151 #define LEAF_CONFIRMATION_TIME 200 /* time to consider subnet a leaf */ 152 153 #define NEIGHBOR_PROBE_INTERVAL 10 /* periodic neighbor probe interval */ 154 #define NEIGHBOR_EXPIRE_TIME 140 /* time to consider neighbor gone */ 155 156 #define GROUP_QUERY_INTERVAL 125 /* periodic group query interval */ 157 #define GROUP_EXPIRE_TIME 270 /* time to consider group gone */ 158 #define LEAVE_EXPIRE_TIME 3 /* " " after receiving a leave */ 159 /* Note: LEAVE_EXPIRE_TIME should ideally be shorter, but the resolution of 160 * the timer in mrouted doesn't allow us to make it any shorter. */ 161 162 #define UNREACHABLE 32 /* "infinity" metric, must be <= 64 */ 163 #define DEFAULT_METRIC 1 /* default subnet/tunnel metric */ 164 #define DEFAULT_THRESHOLD 1 /* default subnet/tunnel threshold */ 165 166 #define MAX_RATE_LIMIT 100000 /* max rate limit */ 167 #define DEFAULT_PHY_RATE_LIMIT 0 /* default phyint rate limit */ 168 #define DEFAULT_TUN_RATE_LIMIT 500 /* default tunnel rate limit */ 169 170 #define DEFAULT_CACHE_LIFETIME 300 /* kernel route entry discard time */ 171 #define GRAFT_TIMEOUT_VAL 5 /* retransmission time for grafts */ 172 173 #define OLD_AGE_THRESHOLD 2 174