e576be50 |
1 | /* |
2 | * parse.c |
3 | * - parsing assistance functions (mainly for domains inside datagrams) |
4 | */ |
5 | /* |
6 | * This file is part of adns, which is Copyright (C) 1997, 1998 Ian Jackson |
7 | * |
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) |
11 | * any later version. |
12 | * |
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. |
17 | * |
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. |
21 | */ |
98a3f706 |
22 | |
23 | #include "internal.h" |
24 | |
25 | int vbuf__append_quoted1035(vbuf *vb, const byte *buf, int len) { |
26 | char qbuf[10]; |
27 | int i, ch; |
28 | |
29 | while (len) { |
30 | qbuf[0]= 0; |
31 | for (i=0; i<len; i++) { |
32 | ch= buf[i]; |
33 | if (ch == '.' || ch == '"' || ch == '(' || ch == ')' || |
34 | ch == '@' || ch == ';' || ch == '$') { |
35 | sprintf(qbuf,"\\%c",ch); |
36 | break; |
37 | } else if (ch <= ' ' || ch >= 127) { |
38 | sprintf(qbuf,"\\%03o",ch); |
39 | break; |
40 | } |
41 | } |
42 | if (!adns__vbuf_append(vb,buf,i) || !adns__vbuf_append(vb,qbuf,strlen(qbuf))) |
43 | return 0; |
44 | buf+= i; len-= i; |
45 | } |
46 | return 1; |
47 | } |
48 | |
f1e474dd |
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) { |
53 | fls->ads= ads; |
54 | fls->serv= serv; |
55 | fls->dgram= dgram; |
56 | fls->dglen= dglen; |
57 | fls->max= max; |
58 | fls->cbyte= dmbegin; |
59 | fls->namelen= 0; |
60 | fls->dmend_r= dmend_rlater; |
61 | fls->namelen_r= namelen_rlater; |
62 | } |
98a3f706 |
63 | |
f1e474dd |
64 | adns_status adns__findlabel_next(findlabel_state fls, |
65 | int *lablen_r, int *labstart_r) { |
66 | int lablen, jumped; |
67 | |
68 | jumped= 0; |
98a3f706 |
69 | for (;;) { |
f1e474dd |
70 | fls->cbyte += 2; |
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); |
98a3f706 |
74 | if (!(lablen & 0x0c000)) break; |
75 | if ((lablen & 0x0c000) != 0x0c000) return adns_s_unknownreply; |
f1e474dd |
76 | if (jumped++) { |
68442019 |
77 | adns__diag(ads,fls->serv,fls->qu,"compressed datagram contains loop"); |
f1e474dd |
78 | return adns_s_serverfaulty; |
79 | } |
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; |
98a3f706 |
83 | } |
98a3f706 |
84 | if (lablen) { |
f1e474dd |
85 | if (fls->namelen) fls->namelen++; |
86 | fls->namelen+= lablen; |
87 | if (fls->namelen > DNS_MAXDOMAIN) return adns_s_domaintoolong; |
88 | fls->cbyte+= lablen; |
89 | if (fls->cbyte > fls->dglen) goto x_truncated; |
90 | if (fls->cbyte > fls->max) goto x_serverfaulty; |
91 | } else { |
92 | if (fls->dmend_r) *(fls->dmend_r)= fls->cbyte; |
93 | if (fls->namelen_r) *(fls->namelen_r)= fls->namelen; |
98a3f706 |
94 | } |
f1e474dd |
95 | if (labstart_r) *labstart_r= fls->cbyte; |
98a3f706 |
96 | *lablen_r= lablen; |
97 | return adns_s_ok; |
98 | |
99 | x_truncated: |
100 | *lablen_r= -1; |
101 | return adns_s_ok; |
f1e474dd |
102 | |
103 | x_serverfaulty: |
68442019 |
104 | adns__diag(ads,fls->serv,fls->qu,"label in domain runs beyond end of domain"); |
f1e474dd |
105 | return adns_s_serverfaulty; |
98a3f706 |
106 | } |
107 | |
31144a72 |
108 | adns_status adns__parse_domain(adns_state ads, int serv, vbuf *vb, int flags, |
f1e474dd |
109 | const byte *dgram, int dglen, |
110 | int *cbyte_io, int max) { |
111 | findlabel_state fls; |
112 | |
113 | int cbyte, lablen, labstart, namelen, i, ch; |
98a3f706 |
114 | adns_status st; |
115 | |
f1e474dd |
116 | ands__findlabel_start(&fls,ads,serv, dgram,dglen,max, *cbyte_io,cbyte_io); |
117 | vb->used= 0; |
98a3f706 |
118 | for (;;) { |
f1e474dd |
119 | st= adns__findlabel_next(&fls,&lablen,&labstart); |
98a3f706 |
120 | if (st) return st; |
f1e474dd |
121 | if (lablen<0) { vb->used=0; return adns_s_ok; } |
98a3f706 |
122 | if (!lablen) break; |
f1e474dd |
123 | if (vb->used) |
98a3f706 |
124 | if (!adns__vbuf_append(&qu->ans,".",1)) return adns_s_nolocalmem; |
31144a72 |
125 | if (flags & adns_qf_anyquote) { |
98a3f706 |
126 | if (!vbuf__append_quoted1035(&qu->ans,dgram+labstart,lablen)) |
127 | return adns_s_nolocalmem; |
128 | } else { |
129 | if (!ctype_alpha(dgram[labstart])) return adns_s_invaliddomain; |
f1e474dd |
130 | for (i= labstart+1; i<labstart+lablen; i++) { |
131 | ch= dgram[i]; |
98a3f706 |
132 | if (ch != '-' && !ctype_alpha(ch) && !ctype_digit(ch)) |
133 | return adns_s_invaliddomain; |
134 | } |
135 | if (!adns__vbuf_append(&qu->ans,dgram+labstart,lablen)) |
136 | return adns_s_nolocalmem; |
137 | } |
138 | } |
98a3f706 |
139 | if (!adns__vbuf_append(&qu->ans,"",1)) return adns_s_nolocalmem; |
98a3f706 |
140 | return adns_s_ok; |
98a3f706 |
141 | } |
31144a72 |
142 | |
f1e474dd |
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, |
147 | int *eo_matched_r) { |
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). |
152 | * |
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. |
156 | * |
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 |
165 | * untruncated. |
166 | * |
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 |
169 | * undefined. |
170 | * |
171 | * If an error is returned then *type_r will be undefined too. |
98a3f706 |
172 | */ |
f1e474dd |
173 | findlabel_state fls, eo_fls; |
174 | int cbyte; |
175 | |
176 | int tmp, rdlen, mismatch; |
98a3f706 |
177 | int max, lablen, labstart, namelen, ch; |
178 | int eo_max, eo_lablen, eo_labstart, eo_namelen, eo_ch; |
179 | adns_status st; |
180 | |
181 | cbyte= *cbyte_io; |
98a3f706 |
182 | |
f1e474dd |
183 | ands__findlabel_start(&fls,ads,serv, dgram,dglen,dglen,cbyte,&cbyte); |
184 | if (eo_dgram) { |
185 | ands__findlabel_start(&eo_fls,ads,serv, eo_dgram,eo_dglen,eo_dglen,eo_cbyte,0); |
186 | mismatch= 0; |
187 | } else { |
188 | mismatch= 1; |
189 | } |
190 | |
98a3f706 |
191 | for (;;) { |
f1e474dd |
192 | st= adns__findlabel_next(&fls,&lablen,&labstart); |
98a3f706 |
193 | if (st) return st; |
194 | if (lablen<0) goto x_truncated; |
195 | |
196 | if (!mismatch) { |
f1e474dd |
197 | st= adns__findlabel_next(&eo_fls,&eo_lablen,&eo_labstart); |
198 | assert(!st); assert(eo_lablen>=0); |
98a3f706 |
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; |
204 | } |
205 | } |
206 | } |
207 | if (eo_matched_r) *eo_matched_r= !mismatch; |
208 | |
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; |
215 | cbyte+= rdlen; |
216 | if (cbyte>dglen) goto x_truncated; |
217 | *cbyte_io= cbyte; |
218 | return adns_s_ok; |
219 | |
220 | x_truncated: |
221 | *type_r= -1; |
222 | return 0;; |
223 | } |