| 1 |
--- djbdns-1.05-original/query.c Sun Feb 11 21:11:45 2001 |
| 2 |
+++ djbdns-1.05/query.c Wed Mar 26 15:48:20 2003 |
| 3 |
@@ -91,6 +91,21 @@ |
| 4 |
} |
| 5 |
} |
| 6 |
|
| 7 |
+static int move_name_to_alias(struct query *z,uint32 ttl) |
| 8 |
+{ |
| 9 |
+ int j ; |
| 10 |
+ |
| 11 |
+ if (z->alias[QUERY_MAXALIAS - 1]) return 0 ; |
| 12 |
+ for (j = QUERY_MAXALIAS - 1;j > 0;--j) |
| 13 |
+ z->alias[j] = z->alias[j - 1]; |
| 14 |
+ for (j = QUERY_MAXALIAS - 1;j > 0;--j) |
| 15 |
+ z->aliasttl[j] = z->aliasttl[j - 1]; |
| 16 |
+ z->alias[0] = z->name[0]; |
| 17 |
+ z->aliasttl[0] = ttl; |
| 18 |
+ z->name[0] = 0; |
| 19 |
+ return 1 ; |
| 20 |
+} |
| 21 |
+ |
| 22 |
static int rqa(struct query *z) |
| 23 |
{ |
| 24 |
int i; |
| 25 |
@@ -123,7 +138,6 @@ |
| 26 |
static char *t1 = 0; |
| 27 |
static char *t2 = 0; |
| 28 |
static char *t3 = 0; |
| 29 |
-static char *cname = 0; |
| 30 |
static char *referral = 0; |
| 31 |
static unsigned int *records = 0; |
| 32 |
|
| 33 |
@@ -179,15 +193,14 @@ |
| 34 |
uint16 datalen; |
| 35 |
char *control; |
| 36 |
char *d; |
| 37 |
+ char *owner_name = 0 ; |
| 38 |
const char *dtype; |
| 39 |
unsigned int dlen; |
| 40 |
int flagout; |
| 41 |
- int flagcname; |
| 42 |
int flagreferral; |
| 43 |
int flagsoa; |
| 44 |
uint32 ttl; |
| 45 |
uint32 soattl; |
| 46 |
- uint32 cnamettl; |
| 47 |
int i; |
| 48 |
int j; |
| 49 |
int k; |
| 50 |
@@ -252,7 +265,10 @@ |
| 51 |
|
| 52 |
byte_copy(key,2,DNS_T_CNAME); |
| 53 |
cached = cache_get(key,dlen + 2,&cachedlen,&ttl); |
| 54 |
- if (cached) { |
| 55 |
+ /* A previous explicit query might have caused an empty RRSet to have been |
| 56 |
+ ** cached. Take care to ignore such a thing. |
| 57 |
+ */ |
| 58 |
+ if (cached && cachedlen) { |
| 59 |
if (typematch(DNS_T_CNAME,dtype)) { |
| 60 |
log_cachedanswer(d,DNS_T_CNAME); |
| 61 |
if (!rqa(z)) goto DIE; |
| 62 |
@@ -261,8 +277,11 @@ |
| 63 |
return 1; |
| 64 |
} |
| 65 |
log_cachedcname(d,cached); |
| 66 |
- if (!dns_domain_copy(&cname,cached)) goto DIE; |
| 67 |
- goto CNAME; |
| 68 |
+ if (!z->level) { |
| 69 |
+ if (!move_name_to_alias(z,ttl)) goto DIE ; |
| 70 |
+ } |
| 71 |
+ if (!dns_domain_copy(&z->name[z->level],cached)) goto DIE; |
| 72 |
+ goto NEWNAME; |
| 73 |
} |
| 74 |
|
| 75 |
if (typematch(DNS_T_NS,dtype)) { |
| 76 |
@@ -351,7 +370,7 @@ |
| 77 |
} |
| 78 |
} |
| 79 |
|
| 80 |
- if (!typematch(DNS_T_ANY,dtype) && !typematch(DNS_T_AXFR,dtype) && !typematch(DNS_T_CNAME,dtype) && !typematch(DNS_T_NS,dtype) && !typematch(DNS_T_PTR,dtype) && !typematch(DNS_T_A,dtype) && !typematch(DNS_T_MX,dtype)) { |
| 81 |
+ if (!typematch(DNS_T_ANY,dtype) && !typematch(DNS_T_AXFR,dtype) && !typematch(DNS_T_NS,dtype) && !typematch(DNS_T_PTR,dtype) && !typematch(DNS_T_A,dtype) && !typematch(DNS_T_MX,dtype)) { |
| 82 |
byte_copy(key,2,dtype); |
| 83 |
cached = cache_get(key,dlen + 2,&cachedlen,&ttl); |
| 84 |
if (cached && (cachedlen || byte_diff(dtype,2,DNS_T_ANY))) { |
| 85 |
@@ -471,29 +490,31 @@ |
| 86 |
if (rcode && (rcode != 3)) goto DIE; /* impossible; see irrelevant() */ |
| 87 |
|
| 88 |
flagout = 0; |
| 89 |
- flagcname = 0; |
| 90 |
flagreferral = 0; |
| 91 |
flagsoa = 0; |
| 92 |
soattl = 0; |
| 93 |
- cnamettl = 0; |
| 94 |
+ if (!dns_domain_copy(&owner_name,d)) goto DIE; |
| 95 |
+ /* This code assumes that the CNAME chain is presented in the correct |
| 96 |
+ ** order. The example algorithm in RFC 1034 will actually result in this |
| 97 |
+ ** being the case, but the words do not require it to be so. |
| 98 |
+ */ |
| 99 |
for (j = 0;j < numanswers;++j) { |
| 100 |
pos = dns_packet_getname(buf,len,pos,&t1); if (!pos) goto DIE; |
| 101 |
pos = dns_packet_copy(buf,len,pos,header,10); if (!pos) goto DIE; |
| 102 |
|
| 103 |
- if (dns_domain_equal(t1,d)) |
| 104 |
+ if (dns_domain_equal(t1,owner_name)) |
| 105 |
if (byte_equal(header + 2,2,DNS_C_IN)) { /* should always be true */ |
| 106 |
if (typematch(header,dtype)) |
| 107 |
flagout = 1; |
| 108 |
else if (typematch(header,DNS_T_CNAME)) { |
| 109 |
- if (!dns_packet_getname(buf,len,pos,&cname)) goto DIE; |
| 110 |
- flagcname = 1; |
| 111 |
- cnamettl = ttlget(header + 4); |
| 112 |
+ if (!dns_packet_getname(buf,len,pos,&owner_name)) goto DIE; |
| 113 |
} |
| 114 |
} |
| 115 |
|
| 116 |
uint16_unpack_big(header + 8,&datalen); |
| 117 |
pos += datalen; |
| 118 |
} |
| 119 |
+ dns_domain_free(&owner_name) ; |
| 120 |
posauthority = pos; |
| 121 |
|
| 122 |
for (j = 0;j < numauthority;++j) { |
| 123 |
@@ -515,15 +536,6 @@ |
| 124 |
} |
| 125 |
posglue = pos; |
| 126 |
|
| 127 |
- |
| 128 |
- if (!flagcname && !rcode && !flagout && flagreferral && !flagsoa) |
| 129 |
- if (dns_domain_equal(referral,control) || !dns_domain_suffix(referral,control)) { |
| 130 |
- log_lame(whichserver,control,referral); |
| 131 |
- byte_zero(whichserver,4); |
| 132 |
- goto HAVENS; |
| 133 |
- } |
| 134 |
- |
| 135 |
- |
| 136 |
if (records) { alloc_free(records); records = 0; } |
| 137 |
|
| 138 |
k = numanswers + numauthority + numglue; |
| 139 |
@@ -670,24 +682,36 @@ |
| 140 |
|
| 141 |
alloc_free(records); records = 0; |
| 142 |
|
| 143 |
+ if (byte_diff(DNS_T_CNAME,2,dtype)) { |
| 144 |
+ /* This code assumes that the CNAME chain is presented in the correct |
| 145 |
+ ** order. The example algorithm in RFC 1034 will actually result in this |
| 146 |
+ ** being the case, but the words do not require it to be so. |
| 147 |
+ */ |
| 148 |
+ pos = posanswers; |
| 149 |
+ for (j = 0;j < numanswers;++j) { |
| 150 |
+ pos = dns_packet_getname(buf,len,pos,&t1); if (!pos) goto DIE; |
| 151 |
+ pos = dns_packet_copy(buf,len,pos,header,10); if (!pos) goto DIE; |
| 152 |
+ |
| 153 |
+ if (dns_domain_equal(t1,d)) |
| 154 |
+ if (byte_equal(header + 2,2,DNS_C_IN)) { /* should always be true */ |
| 155 |
+ if (typematch(header,DNS_T_CNAME)) { |
| 156 |
+ ttl = ttlget(header + 4); |
| 157 |
+ if (z->level == 0) { |
| 158 |
+ if (!move_name_to_alias(z,ttl)) goto DIE ; |
| 159 |
+ } |
| 160 |
+ if (!dns_packet_getname(buf,len,pos,&z->name[z->level])) goto DIE; |
| 161 |
+ d = z->name[z->level]; |
| 162 |
+ if (!dns_domain_suffix(d,control) || !roots_same(d,control)) |
| 163 |
+ goto NEWNAME ; /* Cannot trust the chain further - restart using current name */ |
| 164 |
+ } |
| 165 |
+ } |
| 166 |
|
| 167 |
- if (flagcname) { |
| 168 |
- ttl = cnamettl; |
| 169 |
- CNAME: |
| 170 |
- if (!z->level) { |
| 171 |
- if (z->alias[QUERY_MAXALIAS - 1]) goto DIE; |
| 172 |
- for (j = QUERY_MAXALIAS - 1;j > 0;--j) |
| 173 |
- z->alias[j] = z->alias[j - 1]; |
| 174 |
- for (j = QUERY_MAXALIAS - 1;j > 0;--j) |
| 175 |
- z->aliasttl[j] = z->aliasttl[j - 1]; |
| 176 |
- z->alias[0] = z->name[0]; |
| 177 |
- z->aliasttl[0] = ttl; |
| 178 |
- z->name[0] = 0; |
| 179 |
+ uint16_unpack_big(header + 8,&datalen); |
| 180 |
+ pos += datalen; |
| 181 |
} |
| 182 |
- if (!dns_domain_copy(&z->name[z->level],cname)) goto DIE; |
| 183 |
- goto NEWNAME; |
| 184 |
} |
| 185 |
|
| 186 |
+ /* A "no such name" error applies to the end of any CNAME chain, not to the start. */ |
| 187 |
if (rcode == 3) { |
| 188 |
log_nxdomain(whichserver,d,soattl); |
| 189 |
cachegeneric(DNS_T_ANY,d,"",0,soattl); |
| 190 |
@@ -700,10 +724,26 @@ |
| 191 |
return 1; |
| 192 |
} |
| 193 |
|
| 194 |
+ /* We check for a lame server _after_ we have cached any records that it |
| 195 |
+ ** might have returned to us. This copes better with the incorrect |
| 196 |
+ ** behaviour of one content DNS server software that doesn't return |
| 197 |
+ ** complete CNAME chains but instead returns only the first link in a |
| 198 |
+ ** chain followed by a lame delegation to the same server. |
| 199 |
+ ** Also: We check for a lame server _after_ following the CNAME chain. The |
| 200 |
+ ** delegation in a referral answer applies to the _end_ of the chain, not |
| 201 |
+ ** to the beginning. |
| 202 |
+ */ |
| 203 |
+ if (!rcode && !flagout && flagreferral && !flagsoa) |
| 204 |
+ if (dns_domain_equal(referral,control) || !dns_domain_suffix(referral,control)) { |
| 205 |
+ log_lame(whichserver,control,referral); |
| 206 |
+ byte_zero(whichserver,4); |
| 207 |
+ goto HAVENS; |
| 208 |
+ } |
| 209 |
+ |
| 210 |
if (!flagout && flagsoa) |
| 211 |
+ /* Don't save empty RRSets for those types that we use as special markers. */ |
| 212 |
if (byte_diff(DNS_T_ANY,2,dtype)) |
| 213 |
- if (byte_diff(DNS_T_AXFR,2,dtype)) |
| 214 |
- if (byte_diff(DNS_T_CNAME,2,dtype)) { |
| 215 |
+ if (byte_diff(DNS_T_AXFR,2,dtype)) { |
| 216 |
save_start(); |
| 217 |
save_finish(dtype,d,soattl); |
| 218 |
log_nodata(whichserver,d,dtype,soattl); |
| 219 |
@@ -815,6 +855,7 @@ |
| 220 |
DIE: |
| 221 |
cleanup(z); |
| 222 |
if (records) { alloc_free(records); records = 0; } |
| 223 |
+ dns_domain_free(&owner_name) ; |
| 224 |
return -1; |
| 225 |
} |
| 226 |
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