1 87a52e04 2005-12-26 devnull #include <u.h>
  2 87a52e04 2005-12-26 devnull #include <libc.h>
  3 87a52e04 2005-12-26 devnull #include <ip.h>
  4 87a52e04 2005-12-26 devnull #include <bio.h>
  5 87a52e04 2005-12-26 devnull #include <ndb.h>
  6 87a52e04 2005-12-26 devnull #include <ctype.h>
  7 87a52e04 2005-12-26 devnull #include "dat.h"
  8 87a52e04 2005-12-26 devnull 
  9 87a52e04 2005-12-26 devnull /*
 10 87a52e04 2005-12-26 devnull  *  format of a binding entry:
 11 87a52e04 2005-12-26 devnull  *	char ipaddr[32];
 12 87a52e04 2005-12-26 devnull  *	char id[32];
 13 87a52e04 2005-12-26 devnull  *	char hwa[32];
 14 87a52e04 2005-12-26 devnull  *	char otime[10];
 15 87a52e04 2005-12-26 devnull  */
 16 87a52e04 2005-12-26 devnull Binding *bcache;
 17 87a52e04 2005-12-26 devnull uchar bfirst[IPaddrlen];
 18 87a52e04 2005-12-26 devnull char *binddir = nil;
 19 87a52e04 2005-12-26 devnull char *xbinddir = "#9/ndb/dhcp";
 20 87a52e04 2005-12-26 devnull 
 21 87a52e04 2005-12-26 devnull /*
 22 87a52e04 2005-12-26 devnull  *  convert a byte array to hex
 23 87a52e04 2005-12-26 devnull  */
 24 87a52e04 2005-12-26 devnull static char
 25 87a52e04 2005-12-26 devnull hex(int x)
 26 87a52e04 2005-12-26 devnull {
 27 87a52e04 2005-12-26 devnull 	if(x < 10)
 28 87a52e04 2005-12-26 devnull 		return x + '0';
 29 87a52e04 2005-12-26 devnull 	return x - 10 + 'a';
 30 87a52e04 2005-12-26 devnull }
 31 87a52e04 2005-12-26 devnull extern char*
 32 87a52e04 2005-12-26 devnull tohex(char *hdr, uchar *p, int len)
 33 87a52e04 2005-12-26 devnull {
 34 87a52e04 2005-12-26 devnull 	char *s, *sp;
 35 87a52e04 2005-12-26 devnull 	int hlen;
 36 87a52e04 2005-12-26 devnull 
 37 87a52e04 2005-12-26 devnull 	hlen = strlen(hdr);
 38 87a52e04 2005-12-26 devnull 	s = malloc(hlen + 2*len + 1);
 39 87a52e04 2005-12-26 devnull 	sp = s;
 40 87a52e04 2005-12-26 devnull 	strcpy(sp, hdr);
 41 87a52e04 2005-12-26 devnull 	sp += hlen;
 42 87a52e04 2005-12-26 devnull 	for(; len > 0; len--){
 43 87a52e04 2005-12-26 devnull 		*sp++ = hex(*p>>4);
 44 87a52e04 2005-12-26 devnull 		*sp++ = hex(*p & 0xf);
 45 87a52e04 2005-12-26 devnull 		p++;
 46 87a52e04 2005-12-26 devnull 	}
 47 87a52e04 2005-12-26 devnull 	*sp = 0;
 48 87a52e04 2005-12-26 devnull 	return s;
 49 87a52e04 2005-12-26 devnull }
 50 87a52e04 2005-12-26 devnull 
 51 87a52e04 2005-12-26 devnull /*
 52 87a52e04 2005-12-26 devnull  *  convert a client id to a string.  If it's already
 53 87a52e04 2005-12-26 devnull  *  ascii, leave it be.  Otherwise, convert it to hex.
 54 87a52e04 2005-12-26 devnull  */
 55 87a52e04 2005-12-26 devnull extern char*
 56 87a52e04 2005-12-26 devnull toid(uchar *p, int n)
 57 87a52e04 2005-12-26 devnull {
 58 87a52e04 2005-12-26 devnull 	int i;
 59 87a52e04 2005-12-26 devnull 	char *s;
 60 87a52e04 2005-12-26 devnull 
 61 87a52e04 2005-12-26 devnull 	for(i = 0; i < n; i++)
 62 87a52e04 2005-12-26 devnull 		if(!isprint(p[i]))
 63 87a52e04 2005-12-26 devnull 			return tohex("id", p, n);
 64 87a52e04 2005-12-26 devnull 	s = malloc(n + 1);
 65 87a52e04 2005-12-26 devnull 	memmove(s, p, n);
 66 87a52e04 2005-12-26 devnull 	s[n] = 0;
 67 87a52e04 2005-12-26 devnull 	return s;
 68 87a52e04 2005-12-26 devnull }
 69 87a52e04 2005-12-26 devnull 
 70 87a52e04 2005-12-26 devnull /*
 71 87a52e04 2005-12-26 devnull  *  increment an ip address
 72 87a52e04 2005-12-26 devnull  */
 73 87a52e04 2005-12-26 devnull static void
 74 87a52e04 2005-12-26 devnull incip(uchar *ip)
 75 87a52e04 2005-12-26 devnull {
 76 87a52e04 2005-12-26 devnull 	int i, x;
 77 87a52e04 2005-12-26 devnull 
 78 87a52e04 2005-12-26 devnull 	for(i = IPaddrlen-1; i >= 0; i--){
 79 87a52e04 2005-12-26 devnull 		x = ip[i];
 80 87a52e04 2005-12-26 devnull 		x++;
 81 87a52e04 2005-12-26 devnull 		ip[i] = x;
 82 87a52e04 2005-12-26 devnull 		if((x & 0x100) == 0)
 83 87a52e04 2005-12-26 devnull 			break;
 84 87a52e04 2005-12-26 devnull 	}
 85 87a52e04 2005-12-26 devnull }
 86 87a52e04 2005-12-26 devnull 
 87 87a52e04 2005-12-26 devnull /*
 88 87a52e04 2005-12-26 devnull  *  find a binding for an id or hardware address
 89 87a52e04 2005-12-26 devnull  */
 90 87a52e04 2005-12-26 devnull static int
 91 87a52e04 2005-12-26 devnull lockopen(char *file)
 92 87a52e04 2005-12-26 devnull {
 93 87a52e04 2005-12-26 devnull 	char err[ERRMAX];
 94 87a52e04 2005-12-26 devnull 	int fd, tries;
 95 87a52e04 2005-12-26 devnull 
 96 87a52e04 2005-12-26 devnull 	for(tries = 0; tries < 5; tries++){
 97 87a52e04 2005-12-26 devnull 		fd = open(file, OLOCK|ORDWR);
 98 87a52e04 2005-12-26 devnull 		if(fd >= 0)
 99 87a52e04 2005-12-26 devnull 			return fd;
100 87a52e04 2005-12-26 devnull print("open %s: %r\n", file);
101 87a52e04 2005-12-26 devnull 		errstr(err, sizeof err);
102 87a52e04 2005-12-26 devnull 		if(strstr(err, "lock")){
103 87a52e04 2005-12-26 devnull 			/* wait for other process to let go of lock */
104 87a52e04 2005-12-26 devnull 			sleep(250);
105 87a52e04 2005-12-26 devnull 
106 87a52e04 2005-12-26 devnull 			/* try again */
107 87a52e04 2005-12-26 devnull 			continue;
108 87a52e04 2005-12-26 devnull 		}
109 87a52e04 2005-12-26 devnull 		if(strstr(err, "exist") || strstr(err, "No such")){
110 87a52e04 2005-12-26 devnull 			/* no file, create an exclusive access file */
111 87a52e04 2005-12-26 devnull 			fd = create(file, ORDWR, DMEXCL|0666);
112 87a52e04 2005-12-26 devnull 			chmod(file, 0666);
113 87a52e04 2005-12-26 devnull 			if(fd >= 0)
114 87a52e04 2005-12-26 devnull 				return fd;
115 87a52e04 2005-12-26 devnull 		}
116 87a52e04 2005-12-26 devnull 	}
117 87a52e04 2005-12-26 devnull 	return -1;
118 87a52e04 2005-12-26 devnull }
119 87a52e04 2005-12-26 devnull 
120 87a52e04 2005-12-26 devnull void
121 87a52e04 2005-12-26 devnull setbinding(Binding *b, char *id, long t)
122 87a52e04 2005-12-26 devnull {
123 87a52e04 2005-12-26 devnull 	if(b->boundto)
124 87a52e04 2005-12-26 devnull 		free(b->boundto);
125 87a52e04 2005-12-26 devnull 
126 87a52e04 2005-12-26 devnull 	b->boundto = strdup(id);
127 87a52e04 2005-12-26 devnull 	b->lease = t;
128 87a52e04 2005-12-26 devnull }
129 87a52e04 2005-12-26 devnull 
130 87a52e04 2005-12-26 devnull static void
131 87a52e04 2005-12-26 devnull parsebinding(Binding *b, char *buf)
132 87a52e04 2005-12-26 devnull {
133 87a52e04 2005-12-26 devnull 	long t;
134 87a52e04 2005-12-26 devnull 	char *id, *p;
135 87a52e04 2005-12-26 devnull 
136 87a52e04 2005-12-26 devnull 	/* parse */
137 87a52e04 2005-12-26 devnull 	t = atoi(buf);
138 87a52e04 2005-12-26 devnull 	id = strchr(buf, '\n');
139 87a52e04 2005-12-26 devnull 	if(id){
140 87a52e04 2005-12-26 devnull 		*id++ = 0;
141 87a52e04 2005-12-26 devnull 		p = strchr(id, '\n');
142 87a52e04 2005-12-26 devnull 		if(p)
143 87a52e04 2005-12-26 devnull 			*p = 0;
144 87a52e04 2005-12-26 devnull 	} else
145 87a52e04 2005-12-26 devnull 		id = "";
146 87a52e04 2005-12-26 devnull 
147 87a52e04 2005-12-26 devnull 	/* replace any past info */
148 87a52e04 2005-12-26 devnull 	setbinding(b, id, t);
149 87a52e04 2005-12-26 devnull }
150 87a52e04 2005-12-26 devnull 
151 87a52e04 2005-12-26 devnull static int
152 87a52e04 2005-12-26 devnull writebinding(int fd, Binding *b)
153 87a52e04 2005-12-26 devnull {
154 87a52e04 2005-12-26 devnull 	Dir *d;
155 87a52e04 2005-12-26 devnull 
156 87a52e04 2005-12-26 devnull 	seek(fd, 0, 0);
157 87a52e04 2005-12-26 devnull 	if(fprint(fd, "%ld\n%s\n", b->lease, b->boundto) < 0)
158 87a52e04 2005-12-26 devnull 		return -1;
159 87a52e04 2005-12-26 devnull 	d = dirfstat(fd);
160 87a52e04 2005-12-26 devnull 	if(d == nil)
161 87a52e04 2005-12-26 devnull 		return -1;
162 87a52e04 2005-12-26 devnull 	b->q.type = d->qid.type;
163 87a52e04 2005-12-26 devnull 	b->q.path = d->qid.path;
164 87a52e04 2005-12-26 devnull 	b->q.vers = d->qid.vers;
165 87a52e04 2005-12-26 devnull 	free(d);
166 87a52e04 2005-12-26 devnull 	return 0;
167 87a52e04 2005-12-26 devnull }
168 87a52e04 2005-12-26 devnull 
169 87a52e04 2005-12-26 devnull /*
170 87a52e04 2005-12-26 devnull  *  synchronize cached binding with file.  the file always wins.
171 87a52e04 2005-12-26 devnull  */
172 87a52e04 2005-12-26 devnull int
173 87a52e04 2005-12-26 devnull syncbinding(Binding *b, int returnfd)
174 87a52e04 2005-12-26 devnull {
175 87a52e04 2005-12-26 devnull 	char buf[512];
176 87a52e04 2005-12-26 devnull 	int i, fd;
177 87a52e04 2005-12-26 devnull 	Dir *d;
178 87a52e04 2005-12-26 devnull 
179 87a52e04 2005-12-26 devnull 	if(binddir == nil)
180 87a52e04 2005-12-26 devnull 		binddir = unsharp(xbinddir);
181 87a52e04 2005-12-26 devnull 
182 87a52e04 2005-12-26 devnull 	snprint(buf, sizeof(buf), "%s/%I", binddir, b->ip);
183 87a52e04 2005-12-26 devnull 	fd = lockopen(buf);
184 87a52e04 2005-12-26 devnull 	if(fd < 0){
185 87a52e04 2005-12-26 devnull 		/* assume someone else is using it */
186 87a52e04 2005-12-26 devnull 		b->lease = time(0) + OfferTimeout;
187 87a52e04 2005-12-26 devnull 		return -1;
188 87a52e04 2005-12-26 devnull 	}
189 87a52e04 2005-12-26 devnull 
190 87a52e04 2005-12-26 devnull 	/* reread if changed */
191 87a52e04 2005-12-26 devnull 	d = dirfstat(fd);
192 87a52e04 2005-12-26 devnull 	if(d != nil)	/* BUG? */
193 87a52e04 2005-12-26 devnull 	if(d->qid.type != b->q.type || d->qid.path != b->q.path || d->qid.vers != b->q.vers){
194 87a52e04 2005-12-26 devnull 		i = read(fd, buf, sizeof(buf)-1);
195 87a52e04 2005-12-26 devnull 		if(i < 0)
196 87a52e04 2005-12-26 devnull 			i = 0;
197 87a52e04 2005-12-26 devnull 		buf[i] = 0;
198 87a52e04 2005-12-26 devnull 		parsebinding(b, buf);
199 87a52e04 2005-12-26 devnull 		b->lasttouched = d->mtime;
200 87a52e04 2005-12-26 devnull 		b->q.path = d->qid.path;
201 87a52e04 2005-12-26 devnull 		b->q.vers = d->qid.vers;
202 87a52e04 2005-12-26 devnull 	}
203 87a52e04 2005-12-26 devnull 
204 87a52e04 2005-12-26 devnull 	free(d);
205 87a52e04 2005-12-26 devnull 
206 87a52e04 2005-12-26 devnull 	if(returnfd)
207 87a52e04 2005-12-26 devnull 		return fd;
208 87a52e04 2005-12-26 devnull 
209 87a52e04 2005-12-26 devnull 	close(fd);
210 87a52e04 2005-12-26 devnull 	return 0;
211 87a52e04 2005-12-26 devnull }
212 87a52e04 2005-12-26 devnull 
213 87a52e04 2005-12-26 devnull extern int
214 87a52e04 2005-12-26 devnull samenet(uchar *ip, Info *iip)
215 87a52e04 2005-12-26 devnull {
216 87a52e04 2005-12-26 devnull 	uchar x[IPaddrlen];
217 87a52e04 2005-12-26 devnull 
218 87a52e04 2005-12-26 devnull 	maskip(iip->ipmask, ip, x);
219 87a52e04 2005-12-26 devnull 	return ipcmp(x, iip->ipnet) == 0;
220 87a52e04 2005-12-26 devnull }
221 87a52e04 2005-12-26 devnull 
222 87a52e04 2005-12-26 devnull /*
223 87a52e04 2005-12-26 devnull  *  create a record for each binding
224 87a52e04 2005-12-26 devnull  */
225 87a52e04 2005-12-26 devnull extern void
226 87a52e04 2005-12-26 devnull initbinding(uchar *first, int n)
227 87a52e04 2005-12-26 devnull {
228 87a52e04 2005-12-26 devnull 	while(n-- > 0){
229 87a52e04 2005-12-26 devnull 		iptobinding(first, 1);
230 87a52e04 2005-12-26 devnull 		incip(first);
231 87a52e04 2005-12-26 devnull 	}
232 87a52e04 2005-12-26 devnull }
233 87a52e04 2005-12-26 devnull 
234 87a52e04 2005-12-26 devnull /*
235 87a52e04 2005-12-26 devnull  *  find a binding for a specific ip address
236 87a52e04 2005-12-26 devnull  */
237 87a52e04 2005-12-26 devnull extern Binding*
238 87a52e04 2005-12-26 devnull iptobinding(uchar *ip, int mk)
239 87a52e04 2005-12-26 devnull {
240 87a52e04 2005-12-26 devnull 	Binding *b;
241 87a52e04 2005-12-26 devnull 
242 87a52e04 2005-12-26 devnull 	for(b = bcache; b; b = b->next){
243 87a52e04 2005-12-26 devnull 		if(ipcmp(b->ip, ip) == 0){
244 87a52e04 2005-12-26 devnull 			syncbinding(b, 0);
245 87a52e04 2005-12-26 devnull 			return b;
246 87a52e04 2005-12-26 devnull 		}
247 87a52e04 2005-12-26 devnull 	}
248 87a52e04 2005-12-26 devnull 
249 87a52e04 2005-12-26 devnull 	if(mk == 0)
250 87a52e04 2005-12-26 devnull 		return 0;
251 87a52e04 2005-12-26 devnull 	b = malloc(sizeof(*b));
252 87a52e04 2005-12-26 devnull 	memset(b, 0, sizeof(*b));
253 87a52e04 2005-12-26 devnull 	ipmove(b->ip, ip);
254 87a52e04 2005-12-26 devnull 	b->next = bcache;
255 87a52e04 2005-12-26 devnull 	bcache = b;
256 87a52e04 2005-12-26 devnull 	syncbinding(b, 0);
257 87a52e04 2005-12-26 devnull 	return b;
258 87a52e04 2005-12-26 devnull }
259 87a52e04 2005-12-26 devnull 
260 87a52e04 2005-12-26 devnull static void
261 87a52e04 2005-12-26 devnull lognolease(Binding *b)
262 87a52e04 2005-12-26 devnull {
263 87a52e04 2005-12-26 devnull 	/* renew the old binding, and hope it eventually goes away */
264 87a52e04 2005-12-26 devnull 	b->offer = 5*60;
265 87a52e04 2005-12-26 devnull 	commitbinding(b);
266 87a52e04 2005-12-26 devnull 
267 87a52e04 2005-12-26 devnull 	/* complain if we haven't in the last 5 minutes */
268 87a52e04 2005-12-26 devnull 	if(now - b->lastcomplained < 5*60)
269 87a52e04 2005-12-26 devnull 		return;
270 87a52e04 2005-12-26 devnull 	syslog(0, blog, "dhcp: lease for %I to %s ended at %ld but still in use\n",
271 87a52e04 2005-12-26 devnull 		b->ip, b->boundto != nil ? b->boundto : "?", b->lease);
272 87a52e04 2005-12-26 devnull 	b->lastcomplained = now;
273 87a52e04 2005-12-26 devnull }
274 87a52e04 2005-12-26 devnull 
275 87a52e04 2005-12-26 devnull /*
276 87a52e04 2005-12-26 devnull  *  find a free binding for a hw addr or id on the same network as iip
277 87a52e04 2005-12-26 devnull  */
278 87a52e04 2005-12-26 devnull extern Binding*
279 87a52e04 2005-12-26 devnull idtobinding(char *id, Info *iip, int ping)
280 87a52e04 2005-12-26 devnull {
281 87a52e04 2005-12-26 devnull 	Binding *b, *oldest;
282 87a52e04 2005-12-26 devnull 	int oldesttime;
283 87a52e04 2005-12-26 devnull 
284 87a52e04 2005-12-26 devnull 	/*
285 87a52e04 2005-12-26 devnull 	 *  first look for an old binding that matches.  that way
286 87a52e04 2005-12-26 devnull 	 *  clients will tend to keep the same ip addresses.
287 87a52e04 2005-12-26 devnull 	 */
288 87a52e04 2005-12-26 devnull 	for(b = bcache; b; b = b->next){
289 87a52e04 2005-12-26 devnull 		if(b->boundto && strcmp(b->boundto, id) == 0){
290 87a52e04 2005-12-26 devnull 			if(!samenet(b->ip, iip))
291 87a52e04 2005-12-26 devnull 				continue;
292 87a52e04 2005-12-26 devnull 
293 87a52e04 2005-12-26 devnull 			/* check with the other servers */
294 87a52e04 2005-12-26 devnull 			syncbinding(b, 0);
295 87a52e04 2005-12-26 devnull 			if(strcmp(b->boundto, id) == 0)
296 87a52e04 2005-12-26 devnull 				return b;
297 87a52e04 2005-12-26 devnull 		}
298 87a52e04 2005-12-26 devnull 	}
299 87a52e04 2005-12-26 devnull 
300 87a52e04 2005-12-26 devnull print("looking for old for %I\n", iip->ipnet);
301 87a52e04 2005-12-26 devnull 
302 87a52e04 2005-12-26 devnull 	/*
303 87a52e04 2005-12-26 devnull 	 *  look for oldest binding that we think is unused
304 87a52e04 2005-12-26 devnull 	 */
305 87a52e04 2005-12-26 devnull 	for(;;){
306 87a52e04 2005-12-26 devnull 		oldest = nil;
307 87a52e04 2005-12-26 devnull 		oldesttime = 0;
308 87a52e04 2005-12-26 devnull 		for(b = bcache; b; b = b->next){
309 87a52e04 2005-12-26 devnull print("tried %d now %d lease %d exp %d %I\n", b->tried, now, b->lease, b->expoffer, b->ip);
310 87a52e04 2005-12-26 devnull 			if(b->tried != now)
311 87a52e04 2005-12-26 devnull 			if(b->lease < now && b->expoffer < now && samenet(b->ip, iip))
312 87a52e04 2005-12-26 devnull 			if(oldest == nil || b->lasttouched < oldesttime){
313 87a52e04 2005-12-26 devnull 				/* sync and check again */
314 87a52e04 2005-12-26 devnull 				syncbinding(b, 0);
315 87a52e04 2005-12-26 devnull 				if(b->lease < now && b->expoffer < now && samenet(b->ip, iip))
316 87a52e04 2005-12-26 devnull 				if(oldest == nil || b->lasttouched < oldesttime){
317 87a52e04 2005-12-26 devnull 					oldest = b;
318 87a52e04 2005-12-26 devnull print("have oldest\n");
319 87a52e04 2005-12-26 devnull 					oldesttime = b->lasttouched;
320 87a52e04 2005-12-26 devnull 				}
321 87a52e04 2005-12-26 devnull 			}
322 87a52e04 2005-12-26 devnull 		}
323 87a52e04 2005-12-26 devnull 		if(oldest == nil)
324 87a52e04 2005-12-26 devnull 			break;
325 87a52e04 2005-12-26 devnull 
326 87a52e04 2005-12-26 devnull 		/* make sure noone is still using it */
327 87a52e04 2005-12-26 devnull 		oldest->tried = now;
328 87a52e04 2005-12-26 devnull print("return oldest\n");
329 87a52e04 2005-12-26 devnull 		if(ping == 0 || icmpecho(oldest->ip) == 0)
330 87a52e04 2005-12-26 devnull 			return oldest;
331 87a52e04 2005-12-26 devnull 
332 87a52e04 2005-12-26 devnull 		lognolease(oldest);	/* sets lastcomplained */
333 87a52e04 2005-12-26 devnull 	}
334 87a52e04 2005-12-26 devnull 
335 87a52e04 2005-12-26 devnull 	/* try all bindings */
336 87a52e04 2005-12-26 devnull 	for(b = bcache; b; b = b->next){
337 87a52e04 2005-12-26 devnull 		syncbinding(b, 0);
338 87a52e04 2005-12-26 devnull 		if(b->tried != now)
339 87a52e04 2005-12-26 devnull 		if(b->lease < now && b->expoffer < now && samenet(b->ip, iip)){
340 87a52e04 2005-12-26 devnull 			b->tried = now;
341 87a52e04 2005-12-26 devnull 			if(ping == 0 || icmpecho(b->ip) == 0)
342 87a52e04 2005-12-26 devnull 				return b;
343 87a52e04 2005-12-26 devnull 
344 87a52e04 2005-12-26 devnull 			lognolease(b);
345 87a52e04 2005-12-26 devnull 		}
346 87a52e04 2005-12-26 devnull 	}
347 87a52e04 2005-12-26 devnull 
348 87a52e04 2005-12-26 devnull 	/* nothing worked, give up */
349 87a52e04 2005-12-26 devnull 	return 0;
350 87a52e04 2005-12-26 devnull }
351 87a52e04 2005-12-26 devnull 
352 87a52e04 2005-12-26 devnull /*
353 87a52e04 2005-12-26 devnull  *  create an offer
354 87a52e04 2005-12-26 devnull  */
355 87a52e04 2005-12-26 devnull extern void
356 87a52e04 2005-12-26 devnull mkoffer(Binding *b, char *id, long leasetime)
357 87a52e04 2005-12-26 devnull {
358 87a52e04 2005-12-26 devnull 	if(leasetime <= 0){
359 87a52e04 2005-12-26 devnull 		if(b->lease > now + minlease)
360 87a52e04 2005-12-26 devnull 			leasetime = b->lease - now;
361 87a52e04 2005-12-26 devnull 		else
362 87a52e04 2005-12-26 devnull 			leasetime = minlease;
363 87a52e04 2005-12-26 devnull 	}
364 87a52e04 2005-12-26 devnull 	if(b->offeredto)
365 87a52e04 2005-12-26 devnull 		free(b->offeredto);
366 87a52e04 2005-12-26 devnull 	b->offeredto = strdup(id);
367 87a52e04 2005-12-26 devnull 	b->offer = leasetime;
368 87a52e04 2005-12-26 devnull 	b->expoffer = now + OfferTimeout;
369 87a52e04 2005-12-26 devnull }
370 87a52e04 2005-12-26 devnull 
371 87a52e04 2005-12-26 devnull /*
372 87a52e04 2005-12-26 devnull  *  find an offer for this id
373 87a52e04 2005-12-26 devnull  */
374 87a52e04 2005-12-26 devnull extern Binding*
375 87a52e04 2005-12-26 devnull idtooffer(char *id, Info *iip)
376 87a52e04 2005-12-26 devnull {
377 87a52e04 2005-12-26 devnull 	Binding *b;
378 87a52e04 2005-12-26 devnull 
379 87a52e04 2005-12-26 devnull 	/* look for an offer to this id */
380 87a52e04 2005-12-26 devnull 	for(b = bcache; b; b = b->next){
381 87a52e04 2005-12-26 devnull print("%I %I ? offeredto %s id %s\n", b->ip, iip->ipnet, b->offeredto, id);
382 87a52e04 2005-12-26 devnull 		if(b->offeredto && strcmp(b->offeredto, id) == 0 && samenet(b->ip, iip)){
383 87a52e04 2005-12-26 devnull 			/* make sure some other system hasn't stolen it */
384 87a52e04 2005-12-26 devnull 			syncbinding(b, 0);
385 87a52e04 2005-12-26 devnull print("b->lease %d now %d boundto %s offered %s\n", b->lease, now, b->boundto, b->offeredto);
386 87a52e04 2005-12-26 devnull 			if(b->lease < now
387 87a52e04 2005-12-26 devnull 			|| (b->boundto && strcmp(b->boundto, b->offeredto) == 0))
388 87a52e04 2005-12-26 devnull 				return b;
389 87a52e04 2005-12-26 devnull 		}
390 87a52e04 2005-12-26 devnull 	}
391 87a52e04 2005-12-26 devnull 	return 0;
392 87a52e04 2005-12-26 devnull }
393 87a52e04 2005-12-26 devnull 
394 87a52e04 2005-12-26 devnull /*
395 87a52e04 2005-12-26 devnull  *  commit a lease, this could fail
396 87a52e04 2005-12-26 devnull  */
397 87a52e04 2005-12-26 devnull extern int
398 87a52e04 2005-12-26 devnull commitbinding(Binding *b)
399 87a52e04 2005-12-26 devnull {
400 87a52e04 2005-12-26 devnull 	int fd;
401 87a52e04 2005-12-26 devnull 	long now;
402 87a52e04 2005-12-26 devnull 
403 87a52e04 2005-12-26 devnull 	now = time(0);
404 87a52e04 2005-12-26 devnull 
405 87a52e04 2005-12-26 devnull 	if(b->offeredto == 0)
406 87a52e04 2005-12-26 devnull 		return -1;
407 87a52e04 2005-12-26 devnull 	fd = syncbinding(b, 1);
408 87a52e04 2005-12-26 devnull 	if(fd < 0)
409 87a52e04 2005-12-26 devnull 		return -1;
410 87a52e04 2005-12-26 devnull 	if(b->lease > now && b->boundto && strcmp(b->boundto, b->offeredto) != 0){
411 87a52e04 2005-12-26 devnull 		close(fd);
412 87a52e04 2005-12-26 devnull 		return -1;
413 87a52e04 2005-12-26 devnull 	}
414 87a52e04 2005-12-26 devnull 	setbinding(b, b->offeredto, now + b->offer);
415 87a52e04 2005-12-26 devnull 	b->lasttouched = now;
416 87a52e04 2005-12-26 devnull 	
417 87a52e04 2005-12-26 devnull 	if(writebinding(fd, b) < 0){
418 87a52e04 2005-12-26 devnull 		close(fd);
419 87a52e04 2005-12-26 devnull 		return -1;
420 87a52e04 2005-12-26 devnull 	}
421 87a52e04 2005-12-26 devnull 	close(fd);
422 87a52e04 2005-12-26 devnull 	return 0;
423 87a52e04 2005-12-26 devnull }
424 87a52e04 2005-12-26 devnull 
425 87a52e04 2005-12-26 devnull /*
426 87a52e04 2005-12-26 devnull  *  commit a lease, this could fail
427 87a52e04 2005-12-26 devnull  */
428 87a52e04 2005-12-26 devnull extern int
429 87a52e04 2005-12-26 devnull releasebinding(Binding *b, char *id)
430 87a52e04 2005-12-26 devnull {
431 87a52e04 2005-12-26 devnull 	int fd;
432 87a52e04 2005-12-26 devnull 	long now;
433 87a52e04 2005-12-26 devnull 
434 87a52e04 2005-12-26 devnull 	now = time(0);
435 87a52e04 2005-12-26 devnull 
436 87a52e04 2005-12-26 devnull 	fd = syncbinding(b, 1);
437 87a52e04 2005-12-26 devnull 	if(fd < 0)
438 87a52e04 2005-12-26 devnull 		return -1;
439 87a52e04 2005-12-26 devnull 	if(b->lease > now && b->boundto && strcmp(b->boundto, id) != 0){
440 87a52e04 2005-12-26 devnull 		close(fd);
441 87a52e04 2005-12-26 devnull 		return -1;
442 87a52e04 2005-12-26 devnull 	}
443 87a52e04 2005-12-26 devnull 	b->lease = 0;
444 87a52e04 2005-12-26 devnull 	b->expoffer = 0;
445 87a52e04 2005-12-26 devnull 	
446 87a52e04 2005-12-26 devnull 	if(writebinding(fd, b) < 0){
447 87a52e04 2005-12-26 devnull 		close(fd);
448 87a52e04 2005-12-26 devnull 		return -1;
449 87a52e04 2005-12-26 devnull 	}
450 87a52e04 2005-12-26 devnull 	close(fd);
451 87a52e04 2005-12-26 devnull 	return 0;
452 87a52e04 2005-12-26 devnull }