2 * The mrouted program is covered by the license in the accompanying file
3 * named "LICENSE". Use of the mrouted program represents acceptance of
4 * the terms and conditions listed in that file.
6 * The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
7 * Leland Stanford Junior University.
10 * $FreeBSD: src/usr.sbin/mrouted/dvmrp.h,v 1.9 1999/08/28 01:17:03 peter Exp $
11 * dvmrp.h,v 3.8.4.5 1997/11/18 23:25:57 fenner Exp
15 * A DVMRP message consists of an IP header + an IGMP header + (for some types)
16 * zero or more bytes of data.
18 * For REPORT messages, the data is route information; the route information
19 * consists of one or more lists of the following form:
21 * (mask, (origin, metric), (origin, metric), ...)
25 * "mask" is the subnet mask for all the origins in the list.
26 * It is always THREE bytes long, containing the low-order
27 * three bytes of the mask (the high-order byte is always
28 * 0xff and therefore need not be transmitted).
30 * "origin" is the number of a subnet from which multicast datagrams
31 * may originate. It is from one to four bytes long,
32 * depending on the value of "mask":
33 * if all bytes of the mask are zero
34 * the subnet number is one byte long
35 * else if the low-order two bytes of the mask are zero
36 * the subnet number is two bytes long
37 * else if the lowest-order byte of the mask is zero
38 * the subnet number is three bytes long,
40 * the subnet number is four bytes long.
42 * "metric" is a one-byte value consisting of two subfields:
43 * - the high-order bit is a flag which, when set, indicates
44 * the last (origin, metric) pair of a list.
45 * - the low-order seven bits contain the routing metric for
46 * the corresponding origin, relative to the sender of the
47 * DVMRP report. The metric may have the value of UNREACHABLE
48 * added to it as a "split horizon" indication (so called
49 * "poisoned reverse").
51 * Within a list, the origin subnet numbers must be in ascending order, and
52 * the lists themselves are in order of increasing mask value. A message may
53 * not exceed 576 bytes, the default maximum IP reassembly size, including
54 * the IP and IGMP headers; the route information may be split across more
55 * than one message if necessary, by terminating a list in one message and
56 * starting a new list in the next message (repeating the same mask value,
59 * For NEIGHBORS messages, the data is neighboring-router information
60 * consisting of one or more lists of the following form:
62 * (local-addr, metric, threshold, ncount, neighbor, neighbor, ...)
66 * "local-addr" is the sending router's address as seen by the neighbors
67 * in this list; it is always four bytes long.
68 * "metric" is a one-byte unsigned value, the TTL `cost' of forwarding
69 * packets to any of the neighbors on this list.
70 * "threshold" is a one-byte unsigned value, a lower bound on the TTL a
71 * packet must have to be forwarded to any of the neighbors on
73 * "ncount" is the number of neighbors in this list.
74 * "neighbor" is the address of a neighboring router, four bytes long.
76 * As with REPORT messages, NEIGHBORS messages should not exceed 576 bytes,
77 * including the IP and IGMP headers; split longer messages by terminating the
78 * list in one and continuing in another, repeating the local-addr, etc., if
81 * For NEIGHBORS2 messages, the data is identical to NEIGHBORS except
82 * there is a flags byte before the neighbor count:
84 * (local-addr, metric, threshold, flags, ncount, neighbor, neighbor, ...)
88 * DVMRP message types (carried in the "code" field of an IGMP header)
90 #define DVMRP_PROBE 1 /* for finding neighbors */
91 #define DVMRP_REPORT 2 /* for reporting some or all routes */
92 #define DVMRP_ASK_NEIGHBORS 3 /* sent by mapper, asking for a list */
93 /* of this router's neighbors. */
94 #define DVMRP_NEIGHBORS 4 /* response to such a request */
95 #define DVMRP_ASK_NEIGHBORS2 5 /* as above, want new format reply */
96 #define DVMRP_NEIGHBORS2 6
97 #define DVMRP_PRUNE 7 /* prune message */
98 #define DVMRP_GRAFT 8 /* graft message */
99 #define DVMRP_GRAFT_ACK 9 /* graft acknowledgement */
100 #define DVMRP_INFO_REQUEST 10 /* information request */
101 #define DVMRP_INFO_REPLY 11 /* information reply */
104 * 'flags' byte values in DVMRP_NEIGHBORS2 reply.
106 #define DVMRP_NF_TUNNEL 0x01 /* neighbors reached via tunnel */
107 #define DVMRP_NF_SRCRT 0x02 /* tunnel uses IP source routing */
108 #define DVMRP_NF_PIM 0x04 /* neighbor is a PIM neighbor */
109 #define DVMRP_NF_DOWN 0x10 /* kernel state of interface */
110 #define DVMRP_NF_DISABLED 0x20 /* administratively disabled */
111 #define DVMRP_NF_QUERIER 0x40 /* I am the subnet's querier */
112 #define DVMRP_NF_LEAF 0x80 /* Neighbor reports that it is a leaf */
115 * Request/reply types for info queries/replies
117 #define DVMRP_INFO_VERSION 1 /* version string */
118 #define DVMRP_INFO_NEIGHBORS 2 /* neighbors2 data */
121 * Limit on length of route data
123 #define MAX_IP_PACKET_LEN 576
124 #define MIN_IP_HEADER_LEN 20
125 #define MAX_IP_HEADER_LEN 60
126 #define MAX_DVMRP_DATA_LEN \
127 ( MAX_IP_PACKET_LEN - MAX_IP_HEADER_LEN - IGMP_MINLEN )
130 * Various protocol constants (all times in seconds)
132 /* address for multicast DVMRP msgs */
133 #define INADDR_DVMRP_GROUP (u_int32)0xe0000004 /* 224.0.0.4 */
135 * The IGMPv2 <netinet/in.h> defines INADDR_ALLRTRS_GROUP, but earlier
136 * ones don't, so we define it conditionally here.
138 #ifndef INADDR_ALLRTRS_GROUP
139 /* address for multicast mtrace msg */
140 #define INADDR_ALLRTRS_GROUP (u_int32)0xe0000002 /* 224.0.0.2 */
143 #define ROUTE_MAX_REPORT_DELAY 5 /* max delay for reporting changes */
144 /* (This is the timer interrupt */
145 /* interval; all times must be */
146 /* multiples of this value.) */
148 #define ROUTE_REPORT_INTERVAL 60 /* periodic route report interval */
149 #define ROUTE_SWITCH_TIME 140 /* time to switch to equivalent gw */
150 #define ROUTE_EXPIRE_TIME 200 /* time to mark route invalid */
151 #define ROUTE_DISCARD_TIME 340 /* time to garbage collect route */
153 #define LEAF_CONFIRMATION_TIME 200 /* time to consider subnet a leaf */
155 #define NEIGHBOR_PROBE_INTERVAL 10 /* periodic neighbor probe interval */
156 #define NEIGHBOR_EXPIRE_TIME 30 /* time to consider neighbor gone */
157 #define OLD_NEIGHBOR_EXPIRE_TIME 140 /* time to consider neighbor gone */
159 #define UNREACHABLE 32 /* "infinity" metric, must be <= 64 */
160 #define DEFAULT_METRIC 1 /* default subnet/tunnel metric */
161 #define DEFAULT_THRESHOLD 1 /* default subnet/tunnel threshold */
163 #define MAX_RATE_LIMIT 100000 /* max rate limit */
164 #define DEFAULT_PHY_RATE_LIMIT 0 /* default phyint rate limit */
165 #define DEFAULT_TUN_RATE_LIMIT 0 /* default tunnel rate limit */
167 #define DEFAULT_CACHE_LIFETIME 300 /* kernel route entry discard time */
168 #define MIN_CACHE_LIFETIME 60 /* minimum allowed cache lifetime */
169 #define AVERAGE_PRUNE_LIFETIME 7200 /* average lifetime of prunes sent */
170 #define MIN_PRUNE_LIFETIME 120 /* minimum allowed prune lifetime */
171 #define GRAFT_TIMEOUT_VAL 5 /* retransmission time for grafts */
172 #define PRUNE_REXMIT_VAL 3 /* initial time for prune rexmission*/