1 #include <u.h>
2 #include <libc.h>
3 #include <bio.h>
4 #include <ndb.h>
5 #include <ip.h>
6 
7 enum
8 {
9 	Ffound=	1<<0,
10 	Fignore=	1<<1,
11 	Faddr=	1<<2
12 };
13 
14 static Ndbtuple*	filter(Ndb *db, Ndbtuple *t, Ndbtuple *f);
15 static Ndbtuple*	mkfilter(int argc, char **argv);
16 static int		filtercomplete(Ndbtuple *f);
17 static int		prefixlen(uchar *ip);
18 static Ndbtuple*	subnet(Ndb *db, uchar *net, Ndbtuple *f, int prefix);
19 
20 /* make a filter to be used in filter */
21 static Ndbtuple*
22 mkfilter(int argc, char **argv)
23 {
24 	Ndbtuple *t, *first, *last;
25 	char *p;
26 
27 	last = first = nil;
28 	while(argc-- > 0){
29 		t = ndbnew(0, 0);
30 		if(first)
31 			last->entry = t;
32 		else
33 			first = t;
34 		last = t;
35 		p = *argv++;
36 		if(*p == '@'){
37 			t->ptr |= Faddr;
38 			p++;
39 		}
40 		strncpy(t->attr, p, sizeof(t->attr)-1);
41 	}
42 	return first;
43 }
44 
45 /* return true if every pair of filter has been used */
46 static int
47 filtercomplete(Ndbtuple *f)
48 {
49 	for(; f; f = f->entry)
50 		if((f->ptr & Fignore) == 0)
51 			return 0;
52 	return 1;
53 }
54 
55 /* set the attribute of all entries in a tuple */
56 static Ndbtuple*
57 setattr(Ndbtuple *t, char *attr)
58 {
59 	Ndbtuple *nt;
60 
61 	for(nt = t; nt; nt = nt->entry)
62 		strcpy(nt->attr, attr);
63 	return t;
64 }
65 
66 /*
67  *  return only the attr/value pairs in t maching the filter, f.
68  *  others are freed.  line structure is preserved.
69  */
70 static Ndbtuple*
71 filter(Ndb *db, Ndbtuple *t, Ndbtuple *f)
72 {
73 	Ndbtuple *nt, *nf, *next;
74 
75 	/* filter out what we don't want */
76 	for(nt = t; nt; nt = next){
77 		next = nt->entry;
78 
79 		/* look through filter */
80 		for(nf = f; nf != nil; nf = nf->entry){
81 			if(!(nf->ptr&Fignore) && strcmp(nt->attr, nf->attr) == 0)
82 				break;
83 		}
84 		if(nf == nil){
85 			/* remove nt from t */
86 			t = ndbdiscard(t, nt);
87 		} else {
88 			if(nf->ptr & Faddr)
89 				t = ndbsubstitute(t, nt, setattr(ndbgetipaddr(db, nt->val), nt->attr));
90 			nf->ptr |= Ffound;
91 		}
92 	}
93 
94 	/* remember filter etnries that matched */
95 	for(nf = f; nf != nil; nf = nf->entry)
96 		if(nf->ptr & Ffound)
97 			nf->ptr = (nf->ptr & ~Ffound) | Fignore;
98 
99 	return t;
100 }
101 
102 static int
103 prefixlen(uchar *ip)
104 {
105 	int y, i;
106 
107 	for(y = IPaddrlen-1; y >= 0; y--)
108 		for(i = 8; i > 0; i--)
109 			if(ip[y] & (1<<(8-i)))
110 				return y*8 + i;
111 	return 0;
112 }
113 
114 /*
115  *  look through a containing subset
116  */
117 static Ndbtuple*
118 subnet(Ndb *db, uchar *net, Ndbtuple *f, int prefix)
119 {
120 	Ndbs s;
121 	Ndbtuple *t, *nt, *xt;
122 	char netstr[128];
123 	uchar mask[IPaddrlen];
124 	int masklen;
125 
126 	t = nil;
127 	sprint(netstr, "%I", net);
128 	nt = ndbsearch(db, &s, "ip", netstr);
129 	while(nt != nil){
130 		xt = ndbfindattr(nt, nt, "ipnet");
131 		if(xt){
132 			xt = ndbfindattr(nt, nt, "ipmask");
133 			if(xt)
134 				parseipmask(mask, xt->val);
135 			else
136 				ipmove(mask, defmask(net));
137 			masklen = prefixlen(mask);
138 			if(masklen <= prefix)
139 				t = ndbconcatenate(t, filter(db, nt, f));
140 		} else
141 			ndbfree(nt);
142 		nt = ndbsnext(&s, "ip", netstr);
143 	}
144 	return t;
145 }
146 
147 /*
148  *  fill in all the requested attributes for a system.
149  *  if the system's entry doesn't have all required,
150  *  walk through successively more inclusive networks
151  *  for inherited attributes.
152  */
153 Ndbtuple*
154 ndbipinfo(Ndb *db, char *attr, char *val, char **alist, int n)
155 {
156 	Ndbtuple *t, *nt, *f;
157 	Ndbs s;
158 	char *ipstr;
159 	uchar net[IPaddrlen];
160 	uchar ip[IPaddrlen];
161 	int prefix, smallestprefix;
162 	int force;
163 
164 	/* just in case */
165 	fmtinstall('I', eipfmt);
166 	fmtinstall('M', eipfmt);
167 
168 	/* get needed attributes */
169 	f = mkfilter(n, alist);
170 
171 	/*
172 	 *  first look for a matching entry with an ip address
173 	 */
174 	t = nil;
175 	ipstr = ndbgetvalue(db, &s, attr, val, "ip", &nt);
176 	if(ipstr == nil){
177 		/* none found, make one up */
178 		if(strcmp(attr, "ip") != 0)
179 			return nil;
180 		t = ndbnew("ip", val);
181 		t->line = t;
182 		t->entry = nil;
183 		parseip(net, val);
184 	} else {
185 		/* found one */
186 		while(nt != nil){
187 			nt = ndbreorder(nt, s.t);
188 			t = ndbconcatenate(t, nt);
189 			nt = ndbsnext(&s, attr, val);
190 		}
191 		parseip(net, ipstr);
192 		free(ipstr);
193 	}
194 	ipmove(ip, net);
195 	t = filter(db, t, f);
196 
197 	/*
198 	 *  now go through subnets to fill in any missing attributes
199 	 */
200 	if(isv4(net)){
201 		prefix = 127;
202 		smallestprefix = 100;
203 		force = 0;
204 	} else {
205 		/* in v6, the last 8 bytes have no structure (we hope) */
206 		prefix = 64;
207 		smallestprefix = 2;
208 		memset(net+8, 0, 8);
209 		force = 1;
210 	}
211 
212 	/*
213 	 *  to find a containing network, keep turning off
214 	 *  the lower bit and look for a network with
215 	 *  that address and a shorter mask.  tedius but
216 	 *  complete, we may need to find a trick to speed this up.
217 	 */
218 	for(; prefix >= smallestprefix; prefix--){
219 		if(filtercomplete(f))
220 			break;
221 		if(!force && (net[prefix/8] & (1<<(7-(prefix%8)))) == 0)
222 			continue;
223 		force = 0;
224 		net[prefix/8] &= ~(1<<(7-(prefix%8)));
225 		t = ndbconcatenate(t, subnet(db, net, f, prefix));
226 	}
227 
228 	/*
229 	 *  if there's an unfulfilled ipmask, make one up
230 	 */
231 	nt = ndbfindattr(f, f, "ipmask");
232 	if(nt && !(nt->ptr & Fignore)){
233 		char x[64];
234 
235 		snprint(x, sizeof(x), "%M", defmask(ip));
236 		t = ndbconcatenate(t, ndbnew("ipmask", x));
237 	}
238 
239 	ndbfree(f);
240 	return t;
241 }