xref: /csrg-svn/lib/libc/net/res_mkquery.c (revision 32496)
1 /*
2  * Copyright (c) 1985 Regents of the University of California.
3  * All rights reserved.  The Berkeley software License Agreement
4  * specifies the terms and conditions for redistribution.
5  */
6 
7 #if defined(LIBC_SCCS) && !defined(lint)
8 static char sccsid[] = "@(#)res_mkquery.c	6.6 (Berkeley) 10/22/87";
9 #endif LIBC_SCCS and not lint
10 
11 #include <stdio.h>
12 #include <sys/types.h>
13 #include <netinet/in.h>
14 #include <arpa/nameser.h>
15 #include <resolv.h>
16 
17 /*
18  * Form all types of queries.
19  * Returns the size of the result or -1.
20  */
21 res_mkquery(op, dname, class, type, data, datalen, newrr, buf, buflen)
22 	int op;			/* opcode of query */
23 	char *dname;		/* domain name */
24 	int class, type;	/* class and type of query */
25 	char *data;		/* resource record data */
26 	int datalen;		/* length of data */
27 	struct rrec *newrr;	/* new rr for modify or append */
28 	char *buf;		/* buffer to put query */
29 	int buflen;		/* size of buffer */
30 {
31 	register HEADER *hp;
32 	register char *cp;
33 	register int n;
34 	char dnbuf[MAXDNAME];
35 	char *dnptrs[10], **dpp, **lastdnptr;
36 	extern char *index();
37 
38 #ifdef DEBUG
39 	if (_res.options & RES_DEBUG)
40 		printf("res_mkquery(%d, %s, %d, %d)\n", op, dname, class, type);
41 #endif DEBUG
42 	/*
43 	 * Initialize header fields.
44 	 */
45 	hp = (HEADER *) buf;
46 	hp->id = htons(++_res.id);
47 	hp->opcode = op;
48 	hp->qr = hp->aa = hp->tc = hp->ra = 0;
49 	hp->pr = (_res.options & RES_PRIMARY) != 0;
50 	hp->rd = (_res.options & RES_RECURSE) != 0;
51 	hp->rcode = NOERROR;
52 	hp->qdcount = 0;
53 	hp->ancount = 0;
54 	hp->nscount = 0;
55 	hp->arcount = 0;
56 	cp = buf + sizeof(HEADER);
57 	buflen -= sizeof(HEADER);
58 	dpp = dnptrs;
59 	*dpp++ = buf;
60 	*dpp++ = NULL;
61 	lastdnptr = dnptrs + sizeof(dnptrs)/sizeof(dnptrs[0]);
62 	/*
63 	 * If the domain name contains no dots (single label), then
64 	 * append the default domain name to the one given.
65 	 */
66 	if ((_res.options & RES_DEFNAMES) && dname != 0 && dname[0] != '\0' &&
67 	    index(dname, '.') == NULL) {
68 		if (!(_res.options & RES_INIT))
69 			if (res_init() == -1)
70 				return(-1);
71 		if (_res.defdname[0] != '\0') {
72 			(void)sprintf(dnbuf, "%s.%s", dname, _res.defdname);
73 			dname = dnbuf;
74 		}
75 	}
76 	/*
77 	 * perform opcode specific processing
78 	 */
79 	switch (op) {
80 	case QUERY:
81 		buflen -= QFIXEDSZ;
82 		if ((n = dn_comp(dname, cp, buflen, dnptrs, lastdnptr)) < 0)
83 			return (-1);
84 		cp += n;
85 		buflen -= n;
86 		putshort(type, cp);
87 		cp += sizeof(u_short);
88 		putshort(class, cp);
89 		cp += sizeof(u_short);
90 		hp->qdcount = htons(1);
91 		if (op == QUERY || data == NULL)
92 			break;
93 		/*
94 		 * Make an additional record for completion domain.
95 		 */
96 		buflen -= RRFIXEDSZ;
97 		if ((n = dn_comp(data, cp, buflen, dnptrs, lastdnptr)) < 0)
98 			return (-1);
99 		cp += n;
100 		buflen -= n;
101 		putshort(T_NULL, cp);
102 		cp += sizeof(u_short);
103 		putshort(class, cp);
104 		cp += sizeof(u_short);
105 		putlong(0, cp);
106 		cp += sizeof(u_long);
107 		putshort(0, cp);
108 		cp += sizeof(u_short);
109 		hp->arcount = htons(1);
110 		break;
111 
112 	case IQUERY:
113 		/*
114 		 * Initialize answer section
115 		 */
116 		if (buflen < 1 + RRFIXEDSZ + datalen)
117 			return (-1);
118 		*cp++ = '\0';	/* no domain name */
119 		putshort(type, cp);
120 		cp += sizeof(u_short);
121 		putshort(class, cp);
122 		cp += sizeof(u_short);
123 		putlong(0, cp);
124 		cp += sizeof(u_long);
125 		putshort(datalen, cp);
126 		cp += sizeof(u_short);
127 		if (datalen) {
128 			bcopy(data, cp, datalen);
129 			cp += datalen;
130 		}
131 		hp->ancount = htons(1);
132 		break;
133 
134 #ifdef ALLOW_UPDATES
135 	/*
136 	 * For UPDATEM/UPDATEMA, do UPDATED/UPDATEDA followed by UPDATEA
137 	 * (Record to be modified is followed by its replacement in msg.)
138 	 */
139 	case UPDATEM:
140 	case UPDATEMA:
141 
142 	case UPDATED:
143 		/*
144 		 * The res code for UPDATED and UPDATEDA is the same; user
145 		 * calls them differently: specifies data for UPDATED; server
146 		 * ignores data if specified for UPDATEDA.
147 		 */
148 	case UPDATEDA:
149 		buflen -= RRFIXEDSZ + datalen;
150 		if ((n = dn_comp(dname, cp, buflen, dnptrs, lastdnptr)) < 0)
151 			return (-1);
152 		cp += n;
153 		putshort(type, cp);
154                 cp += sizeof(u_short);
155                 putshort(class, cp);
156                 cp += sizeof(u_short);
157 		putlong(0, cp);
158 		cp += sizeof(u_long);
159 		putshort(datalen, cp);
160                 cp += sizeof(u_short);
161 		if (datalen) {
162 			bcopy(data, cp, datalen);
163 			cp += datalen;
164 		}
165 		if ( (op == UPDATED) || (op == UPDATEDA) ) {
166 			hp->ancount = htons(0);
167 			break;
168 		}
169 		/* Else UPDATEM/UPDATEMA, so drop into code for UPDATEA */
170 
171 	case UPDATEA:	/* Add new resource record */
172 		buflen -= RRFIXEDSZ + datalen;
173 		if ((n = dn_comp(dname, cp, buflen, dnptrs, lastdnptr)) < 0)
174 			return (-1);
175 		cp += n;
176 		putshort(newrr->r_type, cp);
177                 cp += sizeof(u_short);
178                 putshort(newrr->r_class, cp);
179                 cp += sizeof(u_short);
180 		putlong(0, cp);
181 		cp += sizeof(u_long);
182 		putshort(newrr->r_size, cp);
183                 cp += sizeof(u_short);
184 		if (newrr->r_size) {
185 			bcopy(newrr->r_data, cp, newrr->r_size);
186 			cp += newrr->r_size;
187 		}
188 		hp->ancount = htons(0);
189 		break;
190 
191 #endif ALLOW_UPDATES
192 	}
193 	return (cp - buf);
194 }
195