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
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 register struct sap_entry *sap;
97 register struct sap_hash *sh;
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 register struct sap_entry *sap;
128 register struct sap_entry *best = NULL;
129 register int besthops = HOPCNT_INFINITY;
133 for (; sh < &sap_head[SAPHASHSIZ]; sh++)
134 for(sap = sh->forw; sap != (sap_entry *)sh; sap = sap->forw) {
135 if (ServType != sap->sap.ServType)
138 if (ntohs(sap->sap.hops) < besthops) {
140 besthops = ntohs(best->sap.hops);
147 * Add an entry to the SAP table.
149 * If the malloc fail, the entry will silently be thrown away.
152 sap_add(struct sap_info *si, struct sockaddr *from)
154 register struct sap_entry *nsap;
155 register struct sap_hash *sh;
157 if (ntohs(si->hops) == HOPCNT_INFINITY)
161 nsap = malloc(sizeof(struct sap_entry));
166 nsap->source = *from;
168 nsap->ifp = if_ifwithnet(from);
169 nsap->state = RTS_CHANGED;
171 nsap->hash = saphash(si->ServType, si->ServName);
173 sh = &sap_head[nsap->hash & SAPHASHMASK];
176 TRACE_SAP_ACTION("ADD", nsap);
180 * Change an existing SAP entry. If a clone exist for the old one,
181 * check if it is cheaper. If it is change tothe clone, otherwise
182 * delete all the clones.
185 sap_change(struct sap_entry *sap,
187 struct sockaddr *from)
189 struct sap_entry *osap = NULL;
192 TRACE_SAP_ACTION("CHANGE FROM", sap);
194 * If the hopcount (metric) is HOPCNT_INFINITY (16) it means that
195 * a service has gone down. We should keep it like that for 30
196 * seconds, so that it will get broadcast and then change to a
197 * clone if one exist.
199 if (sap->clone && (ntohs(si->hops) != HOPCNT_INFINITY)) {
201 * There are three possibilities:
202 * 1. The new path is cheaper than the old one.
203 * Free all the clones.
205 * 2. The new path is the same cost as the old ones.
206 * If it is on the list of clones remove it
207 * from the clone list and free it.
209 * 3. The new path is more expensive than the old one.
210 * Use the values of the first clone and take it
211 * out of the list, to be freed at the end.
214 if (ntohs(osap->sap.hops) > ntohs(si->hops)) {
215 struct sap_entry *nsap;
219 TRACE_SAP_ACTION("DELETE", osap);
224 } else if (ntohs(osap->sap.hops) == ntohs(si->hops)) {
225 struct sap_entry *psap;
229 if (equal(&osap->source, from)) {
230 psap->clone = osap->clone;
231 TRACE_SAP_ACTION("DELETE", osap);
240 from = &osap->source;
242 sap->clone = osap->clone;
247 sap->ifp = if_ifwithnet(from);
248 sap->state = RTS_CHANGED;
249 if (ntohs(si->hops) == HOPCNT_INFINITY)
250 sap->timer = EXPIRE_TIME;
255 TRACE_SAP_ACTION("DELETE", osap);
258 TRACE_SAP_ACTION("CHANGE TO", sap);
262 * Add a clone to the specified SAP entry. A clone is a different
263 * route to the same service. We must know about them when we use
264 * the split horizon algorithm.
266 * If the malloc fail, the entry will silently be thrown away.
269 sap_add_clone(struct sap_entry *sap,
270 struct sap_info *clone,
271 struct sockaddr *from)
273 register struct sap_entry *nsap;
274 register struct sap_entry *csap;
276 if (ntohs(clone->hops) == HOPCNT_INFINITY)
280 nsap = malloc(sizeof(struct sap_entry));
285 fprintf(ftrace, "CLONE ADD %4.4X %s.\n",
286 ntohs(clone->ServType),
290 nsap->source = *from;
292 nsap->ifp = if_ifwithnet(from);
293 nsap->state = RTS_CHANGED;
295 nsap->hash = saphash(clone->ServType, clone->ServName);
301 TRACE_SAP_ACTION("ADD CLONE", nsap);
305 * Remove a SAP entry from the table and free the memory
308 * If the service have clone, do a sap_change to it and free
312 sap_delete(struct sap_entry *sap)
315 sap_change(sap, &sap->clone->sap, &sap->clone->source);
319 TRACE_SAP_ACTION("DELETE", sap);