tndbipinfo.c - plan9port - [fork] Plan 9 from user space
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tndbipinfo.c (4880B)
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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 }