3 * - parsing assistance functions (mainly for domains inside datagrams)
6 * This file is part of adns, which is Copyright (C) 1997, 1998 Ian Jackson
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2, or (at your option)
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software Foundation,
20 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
25 int vbuf__append_quoted1035(vbuf
*vb
, const byte
*buf
, int len
) {
31 for (i
=0; i
<len
; i
++) {
33 if (ch
== '.' || ch
== '"' || ch
== '(' || ch
== ')' ||
34 ch
== '@' || ch
== ';' || ch
== '$') {
35 sprintf(qbuf
,"\\%c",ch
);
37 } else if (ch
<= ' ' || ch
>= 127) {
38 sprintf(qbuf
,"\\%03o",ch
);
42 if (!adns__vbuf_append(vb
,buf
,i
) || !adns__vbuf_append(vb
,qbuf
,strlen(qbuf
)))
49 void adns__findlabel_start(findlabel_state
*fls
,
50 adns_state ads
, int serv
,
51 const byte
*dgram
, int dglen
, int max
,
52 int dmbegin
, int *dmend_rlater
) {
60 fls
->dmend_r
= dmend_rlater
;
61 fls
->namelen_r
= namelen_rlater
;
64 adns_status
adns__findlabel_next(findlabel_state fls
,
65 int *lablen_r
, int *labstart_r
) {
71 if (fls
->cbyte
> fls
->dglen
) goto x_truncated
;
72 if (fls
->cbyte
> fls
->max
) goto x_serverfaulty
;
73 GET_W(fls
->cbyte
-2,lablen
);
74 if (!(lablen
& 0x0c000)) break;
75 if ((lablen
& 0x0c000) != 0x0c000) return adns_s_unknownreply
;
77 adns__diag(ads
,fls
->serv
,fls
->qu
,"compressed datagram contains loop");
78 return adns_s_serverfaulty
;
80 if (fls
->dmend_r
) *(fls
->dmend_r
)= fls
->cbyte
;
81 fls
->cbyte
= DNS_HDRSIZE
+(lablen
&0x3fff);
82 fls
->dmend_r
= 0; fls
->max
= fls
->dglen
+1;
85 if (fls
->namelen
) fls
->namelen
++;
86 fls
->namelen
+= lablen
;
87 if (fls
->namelen
> DNS_MAXDOMAIN
) return adns_s_domaintoolong
;
89 if (fls
->cbyte
> fls
->dglen
) goto x_truncated
;
90 if (fls
->cbyte
> fls
->max
) goto x_serverfaulty
;
92 if (fls
->dmend_r
) *(fls
->dmend_r
)= fls
->cbyte
;
93 if (fls
->namelen_r
) *(fls
->namelen_r
)= fls
->namelen
;
95 if (labstart_r
) *labstart_r
= fls
->cbyte
;
104 adns__diag(ads
,fls
->serv
,fls
->qu
,"label in domain runs beyond end of domain");
105 return adns_s_serverfaulty
;
108 adns_status
adns__parse_domain(adns_state ads
, int serv
, vbuf
*vb
, int flags
,
109 const byte
*dgram
, int dglen
,
110 int *cbyte_io
, int max
) {
113 int cbyte
, lablen
, labstart
, namelen
, i
, ch
;
116 ands__findlabel_start(&fls
,ads
,serv
, dgram
,dglen
,max
, *cbyte_io
,cbyte_io
);
119 st
= adns__findlabel_next(&fls
,&lablen
,&labstart
);
121 if (lablen
<0) { vb
->used
=0; return adns_s_ok
; }
124 if (!adns__vbuf_append(&qu
->ans
,".",1)) return adns_s_nolocalmem
;
125 if (flags
& adns_qf_anyquote
) {
126 if (!vbuf__append_quoted1035(&qu
->ans
,dgram
+labstart
,lablen
))
127 return adns_s_nolocalmem
;
129 if (!ctype_alpha(dgram
[labstart
])) return adns_s_invaliddomain
;
130 for (i
= labstart
+1; i
<labstart
+lablen
; i
++) {
132 if (ch
!= '-' && !ctype_alpha(ch
) && !ctype_digit(ch
))
133 return adns_s_invaliddomain
;
135 if (!adns__vbuf_append(&qu
->ans
,dgram
+labstart
,lablen
))
136 return adns_s_nolocalmem
;
139 if (!adns__vbuf_append(&qu
->ans
,"",1)) return adns_s_nolocalmem
;
143 adns_status
adns__findrr(adns_state ads
, int serv
,
144 const byte
*dgram
, int dglen
, int *cbyte_io
,
145 int *type_r
, int *class_r
, int *rdlen_r
, int *rdstart_r
,
146 const byte
*eo_dgram
, int eo_dglen
, int eo_cbyte
,
148 /* Finds the extent and some of the contents of an RR in a datagram
149 * and does some checks. The datagram is *dgram, length dglen, and
150 * the RR starts at *cbyte_io (which is updated afterwards to point
151 * to the end of the RR).
153 * The type, class and RRdata length and start are returned iff
154 * the corresponding pointer variables are not null. type_r and
155 * class_r may not be null.
157 * If the caller thinks they know what the owner of the RR ought to
158 * be they can pass in details in eo_*: this is another (or perhaps
159 * the same datagram), and a pointer to where the putative owner
160 * starts in that datagram. In this case *eo_matched_r will be set
161 * to 1 if the datagram matched or 0 if it did not. Either
162 * both eo_dgram and eo_matched_r must both be non-null, or they
163 * must both be null (in which case eo_dglen and eo_cbyte will be ignored).
164 * The eo datagram and contained owner domain MUST be valid and
167 * If there is truncation then *type_r will be set to -1 and
168 * *cbyte_io, *class_r, *rdlen_r, *rdstart_r and *eo_matched_r will be
171 * If an error is returned then *type_r will be undefined too.
173 findlabel_state fls
, eo_fls
;
176 int tmp
, rdlen
, mismatch
;
177 int max
, lablen
, labstart
, namelen
, ch
;
178 int eo_max
, eo_lablen
, eo_labstart
, eo_namelen
, eo_ch
;
183 ands__findlabel_start(&fls
,ads
,serv
, dgram
,dglen
,dglen
,cbyte
,&cbyte
);
185 ands__findlabel_start(&eo_fls
,ads
,serv
, eo_dgram
,eo_dglen
,eo_dglen
,eo_cbyte
,0);
192 st
= adns__findlabel_next(&fls
,&lablen
,&labstart
);
194 if (lablen
<0) goto x_truncated
;
197 st
= adns__findlabel_next(&eo_fls
,&eo_lablen
,&eo_labstart
);
198 assert(!st
); assert(eo_lablen
>=0);
199 if (lablen
!= eo_lablen
) mismatch
= 1;
200 while (!mismatch
&& lablen
-- > 0) {
201 ch
= dgram
[labstart
++]; if (ctype_alpha(ch
)) ch
&= ~32;
202 eo_ch
= eo_dgram
[eo_labstart
++]; if (ctype_alpha(eo_ch
)) eo_ch
&= ~32;
203 if (ch
!= eo_ch
) mismatch
= 1;
207 if (eo_matched_r
) *eo_matched_r
= !mismatch
;
209 if (cbyte
+10>dglen
) goto x_truncated
;
210 GET_W(cbyte
,tmp
); *type_r
= tmp
;
211 GET_W(cbyte
,tmp
); *class_r
= tmp
;
212 cbyte
+= 4; /* we skip the TTL */
213 GET_W(cbyte
,rdlen
); if (rdlen_r
) *rdlen_r
= tmp
;
214 if (rdstart_r
) *rdstart_r
= cbyte
;
216 if (cbyte
>dglen
) goto x_truncated
;