2 * Copyright (c) 1995 John Hay. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * 3. All advertising materials mentioning features or use of this software
13 * must display the following acknowledgement:
14 * This product includes software developed by John Hay.
15 * 4. Neither the name of the author nor the names of any co-contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
19 * THIS SOFTWARE IS PROVIDED BY John Hay AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL John Hay OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * $FreeBSD: src/usr.sbin/IPXrouted/sap_tables.c,v 1.7 1999/08/28 01:15:04 peter Exp $
32 * $DragonFly: src/usr.sbin/IPXrouted/sap_tables.c,v 1.3 2004/03/11 09:38:59 hmp Exp $
39 #define FIXLEN(s) { if ((s)->sa_len == 0) (s)->sa_len = sizeof (*(s));}
41 sap_hash sap_head[SAPHASHSIZ];
48 for (i=0; i<SAPHASHSIZ; i++)
49 sap_head[i].forw = sap_head[i].back =
50 (struct sap_entry *)&sap_head[i];
54 * This hash use the first 14 letters of the ServName and the ServType
55 * to create a 32 bit hash value.
58 saphash(u_short ServType, char *ServName)
61 char name[SERVNAMELEN];
63 bzero(name, SERVNAMELEN);
64 strncpy(name, ServName, SERVNAMELEN);
71 hsh = hsh * SMVAL + (ServType & 0xff);
72 hsh = hsh * SMVAL + (ServType >> 8);
75 hsh = hsh * SMVAL + *ServName++;
85 * Look for an exact match on ServType and ServName. It is
86 * mostly used by the function that process SAP RESPONSE packets.
88 * A hash is created and used to index into the hash table. Then
89 * that list is walk through searching for a match.
91 * If no match is found NULL is returned.
94 sap_lookup(u_short ServType, char *ServName)
96 struct sap_entry *sap;
100 hsh = saphash(ServType, ServName);
101 sh = &sap_head[hsh & SAPHASHMASK];
103 for(sap = sh->forw; sap != (sap_entry *)sh; sap = sap->forw) {
104 if ((hsh == sap->hash) &&
105 (ServType == sap->sap.ServType) &&
106 (strncmp(ServName, sap->sap.ServName, SERVNAMELEN) == 0)) {
114 * This returns the nearest service of the specified type. If no
115 * suitable service is found or if that service is on the interface
116 * where the request came from, NULL is returned.
118 * When checking interfaces clones must be considered also.
121 * Maybe we can use RIP tables to get the fastest service (ticks).
124 sap_nearestserver(ushort ServType, struct interface *ifp)
126 struct sap_entry *sap;
127 struct sap_entry *csap;
129 struct sap_entry *best = NULL;
130 int besthops = HOPCNT_INFINITY;
134 for (; sh < &sap_head[SAPHASHSIZ]; sh++)
135 for(sap = sh->forw; sap != (sap_entry *)sh; sap = sap->forw) {
136 if (ServType != sap->sap.ServType)
139 if (ntohs(sap->sap.hops) < besthops) {
141 besthops = ntohs(best->sap.hops);
149 * Add a entry to the SAP table.
151 * If the malloc fail, the entry will silently be thrown away.
154 sap_add(struct sap_info *si, struct sockaddr *from)
156 struct sap_entry *nsap;
159 if (ntohs(si->hops) == HOPCNT_INFINITY)
163 nsap = malloc(sizeof(struct sap_entry));
168 nsap->source = *from;
170 nsap->ifp = if_ifwithnet(from);
171 nsap->state = RTS_CHANGED;
173 nsap->hash = saphash(si->ServType, si->ServName);
175 sh = &sap_head[nsap->hash & SAPHASHMASK];
178 TRACE_SAP_ACTION("ADD", nsap);
182 * Change an existing SAP entry. If a clone exist for the old one,
183 * check if it is cheaper. If it is change tothe clone, otherwise
184 * delete all the clones.
187 sap_change(struct sap_entry *sap,
189 struct sockaddr *from)
191 struct sap_entry *osap = NULL;
194 TRACE_SAP_ACTION("CHANGE FROM", sap);
196 * If the hopcount (metric) is HOPCNT_INFINITY (16) it means that
197 * a service has gone down. We should keep it like that for 30
198 * seconds, so that it will get broadcast and then change to a
199 * clone if one exist.
201 if (sap->clone && (ntohs(si->hops) != HOPCNT_INFINITY)) {
203 * There are three possibilities:
204 * 1. The new path is cheaper than the old one.
205 * Free all the clones.
207 * 2. The new path is the same cost as the old ones.
208 * If it is on the list of clones remove it
209 * from the clone list and free it.
211 * 3. The new path is more expensive than the old one.
212 * Use the values of the first clone and take it
213 * out of the list, to be freed at the end.
216 if (ntohs(osap->sap.hops) > ntohs(si->hops)) {
217 struct sap_entry *nsap;
221 TRACE_SAP_ACTION("DELETE", osap);
226 } else if (ntohs(osap->sap.hops) == ntohs(si->hops)) {
227 struct sap_entry *psap;
231 if (equal(&osap->source, from)) {
232 psap->clone = osap->clone;
233 TRACE_SAP_ACTION("DELETE", osap);
242 from = &osap->source;
244 sap->clone = osap->clone;
249 sap->ifp = if_ifwithnet(from);
250 sap->state = RTS_CHANGED;
251 if (ntohs(si->hops) == HOPCNT_INFINITY)
252 sap->timer = EXPIRE_TIME;
257 TRACE_SAP_ACTION("DELETE", osap);
260 TRACE_SAP_ACTION("CHANGE TO", sap);
264 * Add a clone to the specified SAP entry. A clone is a different
265 * route to the same service. We must know about them when we use
266 * the split horizon algorithm.
268 * If the malloc fail, the entry will silently be thrown away.
271 sap_add_clone(struct sap_entry *sap,
272 struct sap_info *clone,
273 struct sockaddr *from)
275 struct sap_entry *nsap;
276 struct sap_entry *csap;
278 if (ntohs(clone->hops) == HOPCNT_INFINITY)
282 nsap = malloc(sizeof(struct sap_entry));
287 fprintf(ftrace, "CLONE ADD %04.4X %s.\n",
288 ntohs(clone->ServType),
292 nsap->source = *from;
294 nsap->ifp = if_ifwithnet(from);
295 nsap->state = RTS_CHANGED;
297 nsap->hash = saphash(clone->ServType, clone->ServName);
303 TRACE_SAP_ACTION("ADD CLONE", nsap);
307 * Remove a SAP entry from the table and free the memory
310 * If the service have clone, do a sap_change to it and free
314 sap_delete(struct sap_entry *sap)
317 sap_change(sap, &sap->clone->sap, &sap->clone->source);
321 TRACE_SAP_ACTION("DELETE", sap);