| 1 |
bytegw |
1.1 |
--- djbdns-1.05-original/query.c Sun Feb 11 21:11:45 2001 |
| 2 |
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+++ djbdns-1.05/query.c Wed Mar 26 15:48:20 2003 |
| 3 |
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@@ -91,6 +91,21 @@ |
| 4 |
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} |
| 5 |
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} |
| 6 |
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| 7 |
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+static int move_name_to_alias(struct query *z,uint32 ttl) |
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+{ |
| 9 |
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+ int j ; |
| 10 |
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+ |
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+ if (z->alias[QUERY_MAXALIAS - 1]) return 0 ; |
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+ for (j = QUERY_MAXALIAS - 1;j > 0;--j) |
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+ z->alias[j] = z->alias[j - 1]; |
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+ for (j = QUERY_MAXALIAS - 1;j > 0;--j) |
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+ z->aliasttl[j] = z->aliasttl[j - 1]; |
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+ z->alias[0] = z->name[0]; |
| 17 |
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+ z->aliasttl[0] = ttl; |
| 18 |
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+ z->name[0] = 0; |
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+ return 1 ; |
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+} |
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+ |
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static int rqa(struct query *z) |
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{ |
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int i; |
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@@ -123,7 +138,6 @@ |
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static char *t1 = 0; |
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static char *t2 = 0; |
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static char *t3 = 0; |
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-static char *cname = 0; |
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static char *referral = 0; |
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static unsigned int *records = 0; |
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@@ -179,15 +193,14 @@ |
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uint16 datalen; |
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char *control; |
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char *d; |
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+ char *owner_name = 0 ; |
| 38 |
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const char *dtype; |
| 39 |
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unsigned int dlen; |
| 40 |
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int flagout; |
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- int flagcname; |
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int flagreferral; |
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int flagsoa; |
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uint32 ttl; |
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uint32 soattl; |
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- uint32 cnamettl; |
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int i; |
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int j; |
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int k; |
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@@ -252,7 +265,10 @@ |
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| 52 |
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byte_copy(key,2,DNS_T_CNAME); |
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cached = cache_get(key,dlen + 2,&cachedlen,&ttl); |
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- if (cached) { |
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+ /* A previous explicit query might have caused an empty RRSet to have been |
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+ ** cached. Take care to ignore such a thing. |
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+ */ |
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+ if (cached && cachedlen) { |
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if (typematch(DNS_T_CNAME,dtype)) { |
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log_cachedanswer(d,DNS_T_CNAME); |
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if (!rqa(z)) goto DIE; |
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@@ -261,8 +277,11 @@ |
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return 1; |
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} |
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log_cachedcname(d,cached); |
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- if (!dns_domain_copy(&cname,cached)) goto DIE; |
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- goto CNAME; |
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+ if (!z->level) { |
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+ if (!move_name_to_alias(z,ttl)) goto DIE ; |
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+ } |
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+ if (!dns_domain_copy(&z->name[z->level],cached)) goto DIE; |
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+ goto NEWNAME; |
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} |
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| 75 |
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if (typematch(DNS_T_NS,dtype)) { |
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@@ -351,7 +370,7 @@ |
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} |
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} |
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| 80 |
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- 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 |
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+ 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 |
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byte_copy(key,2,dtype); |
| 83 |
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cached = cache_get(key,dlen + 2,&cachedlen,&ttl); |
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if (cached && (cachedlen || byte_diff(dtype,2,DNS_T_ANY))) { |
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@@ -471,29 +490,31 @@ |
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if (rcode && (rcode != 3)) goto DIE; /* impossible; see irrelevant() */ |
| 87 |
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| 88 |
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flagout = 0; |
| 89 |
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- flagcname = 0; |
| 90 |
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flagreferral = 0; |
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flagsoa = 0; |
| 92 |
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soattl = 0; |
| 93 |
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- cnamettl = 0; |
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+ if (!dns_domain_copy(&owner_name,d)) goto DIE; |
| 95 |
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+ /* This code assumes that the CNAME chain is presented in the correct |
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+ ** order. The example algorithm in RFC 1034 will actually result in this |
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+ ** being the case, but the words do not require it to be so. |
| 98 |
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+ */ |
| 99 |
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for (j = 0;j < numanswers;++j) { |
| 100 |
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pos = dns_packet_getname(buf,len,pos,&t1); if (!pos) goto DIE; |
| 101 |
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pos = dns_packet_copy(buf,len,pos,header,10); if (!pos) goto DIE; |
| 102 |
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| 103 |
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- if (dns_domain_equal(t1,d)) |
| 104 |
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+ if (dns_domain_equal(t1,owner_name)) |
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if (byte_equal(header + 2,2,DNS_C_IN)) { /* should always be true */ |
| 106 |
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if (typematch(header,dtype)) |
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flagout = 1; |
| 108 |
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else if (typematch(header,DNS_T_CNAME)) { |
| 109 |
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- if (!dns_packet_getname(buf,len,pos,&cname)) goto DIE; |
| 110 |
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- flagcname = 1; |
| 111 |
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- cnamettl = ttlget(header + 4); |
| 112 |
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+ if (!dns_packet_getname(buf,len,pos,&owner_name)) goto DIE; |
| 113 |
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} |
| 114 |
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} |
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| 116 |
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uint16_unpack_big(header + 8,&datalen); |
| 117 |
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pos += datalen; |
| 118 |
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} |
| 119 |
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+ dns_domain_free(&owner_name) ; |
| 120 |
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posauthority = pos; |
| 121 |
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| 122 |
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for (j = 0;j < numauthority;++j) { |
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@@ -515,15 +536,6 @@ |
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} |
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posglue = pos; |
| 126 |
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| 127 |
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- |
| 128 |
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- if (!flagcname && !rcode && !flagout && flagreferral && !flagsoa) |
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- if (dns_domain_equal(referral,control) || !dns_domain_suffix(referral,control)) { |
| 130 |
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- log_lame(whichserver,control,referral); |
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- byte_zero(whichserver,4); |
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- goto HAVENS; |
| 133 |
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- } |
| 134 |
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- |
| 135 |
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- |
| 136 |
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if (records) { alloc_free(records); records = 0; } |
| 137 |
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| 138 |
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k = numanswers + numauthority + numglue; |
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@@ -670,24 +682,36 @@ |
| 140 |
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| 141 |
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alloc_free(records); records = 0; |
| 142 |
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| 143 |
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+ if (byte_diff(DNS_T_CNAME,2,dtype)) { |
| 144 |
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+ /* This code assumes that the CNAME chain is presented in the correct |
| 145 |
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+ ** order. The example algorithm in RFC 1034 will actually result in this |
| 146 |
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+ ** being the case, but the words do not require it to be so. |
| 147 |
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+ */ |
| 148 |
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+ pos = posanswers; |
| 149 |
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+ for (j = 0;j < numanswers;++j) { |
| 150 |
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+ pos = dns_packet_getname(buf,len,pos,&t1); if (!pos) goto DIE; |
| 151 |
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+ pos = dns_packet_copy(buf,len,pos,header,10); if (!pos) goto DIE; |
| 152 |
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+ |
| 153 |
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+ if (dns_domain_equal(t1,d)) |
| 154 |
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+ if (byte_equal(header + 2,2,DNS_C_IN)) { /* should always be true */ |
| 155 |
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+ if (typematch(header,DNS_T_CNAME)) { |
| 156 |
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+ ttl = ttlget(header + 4); |
| 157 |
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+ if (z->level == 0) { |
| 158 |
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+ if (!move_name_to_alias(z,ttl)) goto DIE ; |
| 159 |
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+ } |
| 160 |
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+ if (!dns_packet_getname(buf,len,pos,&z->name[z->level])) goto DIE; |
| 161 |
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+ d = z->name[z->level]; |
| 162 |
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+ if (!dns_domain_suffix(d,control) || !roots_same(d,control)) |
| 163 |
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+ goto NEWNAME ; /* Cannot trust the chain further - restart using current name */ |
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+ } |
| 165 |
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+ } |
| 166 |
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| 167 |
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- if (flagcname) { |
| 168 |
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- ttl = cnamettl; |
| 169 |
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- CNAME: |
| 170 |
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- if (!z->level) { |
| 171 |
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- if (z->alias[QUERY_MAXALIAS - 1]) goto DIE; |
| 172 |
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- for (j = QUERY_MAXALIAS - 1;j > 0;--j) |
| 173 |
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- z->alias[j] = z->alias[j - 1]; |
| 174 |
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- for (j = QUERY_MAXALIAS - 1;j > 0;--j) |
| 175 |
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- z->aliasttl[j] = z->aliasttl[j - 1]; |
| 176 |
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- z->alias[0] = z->name[0]; |
| 177 |
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- z->aliasttl[0] = ttl; |
| 178 |
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- z->name[0] = 0; |
| 179 |
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+ uint16_unpack_big(header + 8,&datalen); |
| 180 |
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+ pos += datalen; |
| 181 |
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} |
| 182 |
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- if (!dns_domain_copy(&z->name[z->level],cname)) goto DIE; |
| 183 |
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- goto NEWNAME; |
| 184 |
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} |
| 185 |
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| 186 |
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+ /* A "no such name" error applies to the end of any CNAME chain, not to the start. */ |
| 187 |
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if (rcode == 3) { |
| 188 |
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log_nxdomain(whichserver,d,soattl); |
| 189 |
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cachegeneric(DNS_T_ANY,d,"",0,soattl); |
| 190 |
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@@ -700,10 +724,26 @@ |
| 191 |
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return 1; |
| 192 |
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} |
| 193 |
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| 194 |
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+ /* We check for a lame server _after_ we have cached any records that it |
| 195 |
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+ ** might have returned to us. This copes better with the incorrect |
| 196 |
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+ ** behaviour of one content DNS server software that doesn't return |
| 197 |
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+ ** complete CNAME chains but instead returns only the first link in a |
| 198 |
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+ ** chain followed by a lame delegation to the same server. |
| 199 |
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+ ** Also: We check for a lame server _after_ following the CNAME chain. The |
| 200 |
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+ ** delegation in a referral answer applies to the _end_ of the chain, not |
| 201 |
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+ ** to the beginning. |
| 202 |
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+ */ |
| 203 |
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+ if (!rcode && !flagout && flagreferral && !flagsoa) |
| 204 |
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+ if (dns_domain_equal(referral,control) || !dns_domain_suffix(referral,control)) { |
| 205 |
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+ log_lame(whichserver,control,referral); |
| 206 |
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+ byte_zero(whichserver,4); |
| 207 |
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+ goto HAVENS; |
| 208 |
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+ } |
| 209 |
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+ |
| 210 |
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if (!flagout && flagsoa) |
| 211 |
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+ /* Don't save empty RRSets for those types that we use as special markers. */ |
| 212 |
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if (byte_diff(DNS_T_ANY,2,dtype)) |
| 213 |
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- if (byte_diff(DNS_T_AXFR,2,dtype)) |
| 214 |
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- if (byte_diff(DNS_T_CNAME,2,dtype)) { |
| 215 |
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+ if (byte_diff(DNS_T_AXFR,2,dtype)) { |
| 216 |
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save_start(); |
| 217 |
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save_finish(dtype,d,soattl); |
| 218 |
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log_nodata(whichserver,d,dtype,soattl); |
| 219 |
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@@ -815,6 +855,7 @@ |
| 220 |
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DIE: |
| 221 |
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cleanup(z); |
| 222 |
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if (records) { alloc_free(records); records = 0; } |
| 223 |
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+ dns_domain_free(&owner_name) ; |
| 224 |
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return -1; |
| 225 |
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} |
| 226 |
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