X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/65f1c92a5c06bb7de867f8d72c7eef5f829daeb4..cc00f4af38ebcc8255460398f573ba6e6ec842e3:/src/src/dns.c diff --git a/src/src/dns.c b/src/src/dns.c index 79eb9360e..a2f430993 100644 --- a/src/src/dns.c +++ b/src/src/dns.c @@ -10,16 +10,6 @@ #include "exim.h" -/* Function declaration needed for mutual recursion when A6 records -are supported. */ - -#if HAVE_IPV6 -#ifdef SUPPORT_A6 -static void dns_complete_a6(dns_address ***, dns_answer *, dns_record *, - int, uschar *); -#endif -#endif - /************************************************* * Fake DNS resolver * @@ -640,22 +630,16 @@ the IP address instead of returning -1 with h_error=HOST_NOT_FOUND. Some nameservers are also believed to do this. It is, of course, contrary to the specification of the DNS, so we lock it out. */ -if (( - #ifdef SUPPORT_A6 - type == T_A6 || - #endif - type == T_A || type == T_AAAA) && - string_is_ip_address(name, NULL) != 0) +if ((type == T_A || type == T_AAAA) && string_is_ip_address(name, NULL) != 0) return DNS_NOMATCH; /* If we are running in the test harness, instead of calling the normal resolver (res_search), we call fakens_search(), which recognizes certain special domains, and interfaces to a fake nameserver for certain special zones. */ -if (running_in_test_harness) - dnsa->answerlen = fakens_search(name, type, dnsa->answer, MAXPACKET); -else - dnsa->answerlen = res_search(CCS name, C_IN, type, dnsa->answer, MAXPACKET); +dnsa->answerlen = running_in_test_harness + ? fakens_search(name, type, dnsa->answer, MAXPACKET) + : res_search(CCS name, C_IN, type, dnsa->answer, MAXPACKET); if (dnsa->answerlen > MAXPACKET) { @@ -1052,164 +1036,6 @@ return DNS_FAIL; -/* Support for A6 records has been commented out since they were demoted to -experimental status at IETF 51. */ - -#if HAVE_IPV6 && defined(SUPPORT_A6) - -/************************************************* -* Search DNS block for prefix RRs * -*************************************************/ - -/* Called from dns_complete_a6() to search an additional section or a main -answer section for required prefix records to complete an IPv6 address obtained -from an A6 record. For each prefix record, a recursive call to dns_complete_a6 -is made, with a new copy of the address so far. - -Arguments: - dnsa the DNS answer block - which RESET_ADDITIONAL or RESET_ANSWERS - name name of prefix record - yptrptr pointer to the pointer that points to where to hang the next - dns_address structure - bits number of bits we have already got - bitvec the bits we have already got - -Returns: TRUE if any records were found -*/ - -static BOOL -dns_find_prefix(dns_answer *dnsa, int which, uschar *name, dns_address - ***yptrptr, int bits, uschar *bitvec) -{ -BOOL yield = FALSE; -dns_record *rr; -dns_scan dnss; - -for (rr = dns_next_rr(dnsa, &dnss, which); - rr != NULL; - rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) - { - uschar cbitvec[16]; - if (rr->type != T_A6 || strcmpic(rr->name, name) != 0) continue; - yield = TRUE; - memcpy(cbitvec, bitvec, sizeof(cbitvec)); - dns_complete_a6(yptrptr, dnsa, rr, bits, cbitvec); - } - -return yield; -} - - - -/************************************************* -* Follow chains of A6 records * -*************************************************/ - -/* A6 records may be incomplete, with pointers to other records containing more -bits of the address. There can be a tree structure, leading to a number of -addresses originating from a single initial A6 record. - -Arguments: - yptrptr pointer to the pointer that points to where to hang the next - dns_address structure - dnsa the current DNS answer block - rr the RR we have at present - bits number of bits we have already got - bitvec the bits we have already got - -Returns: nothing -*/ - -static void -dns_complete_a6(dns_address ***yptrptr, dns_answer *dnsa, dns_record *rr, - int bits, uschar *bitvec) -{ -static uschar bitmask[] = { 0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80 }; -uschar *p = (uschar *)(rr->data); -int prefix_len, suffix_len; -int i, j, k; -uschar *chainptr; -uschar chain[264]; -dns_answer cdnsa; - -/* The prefix length is the first byte. It defines the prefix which is missing -from the data in this record as a number of bits. Zero means this is the end of -a chain. The suffix is the data in this record; only sufficient bytes to hold -it are supplied. There may be zero bytes. We have to ignore trailing bits that -we have already obtained from earlier RRs in the chain. */ - -prefix_len = *p++; /* bits */ -suffix_len = (128 - prefix_len + 7)/8; /* bytes */ - -/* If the prefix in this record is greater than the prefix in the previous -record in the chain, we have to ignore the record (RFC 2874). */ - -if (prefix_len > 128 - bits) return; - -/* In this little loop, the number of bits up to and including the current byte -is held in k. If we have none of the bits in this byte, we can just or it into -the current data. If we have all of the bits in this byte, we skip it. -Otherwise, some masking has to be done. */ - -for (i = suffix_len - 1, j = 15, k = 8; i >= 0; i--) - { - int required = k - bits; - if (required >= 8) bitvec[j] |= p[i]; - else if (required > 0) bitvec[j] |= p[i] & bitmask[required]; - j--; /* I tried putting these in the "for" statement, but gcc muttered */ - k += 8; /* about computed values not being used. */ - } - -/* If the prefix_length is zero, we are at the end of a chain. Build a -dns_address item with the current data, hang it onto the end of the chain, -adjust the hanging pointer, and we are done. */ - -if (prefix_len == 0) - { - dns_address *new = store_get(sizeof(dns_address) + 50); - inet_ntop(AF_INET6, bitvec, CS new->address, 50); - new->next = NULL; - **yptrptr = new; - *yptrptr = &(new->next); - return; - } - -/* Prefix length is not zero. Reset the number of bits that we have collected -so far, and extract the chain name. */ - -bits = 128 - prefix_len; -p += suffix_len; - -chainptr = chain; -while ((i = *p++) != 0) - { - if (chainptr != chain) *chainptr++ = '.'; - memcpy(chainptr, p, i); - chainptr += i; - p += i; - } -*chainptr = 0; -chainptr = chain; - -/* Now scan the current DNS response record to see if the additional section -contains the records we want. This processing can be cut out for testing -purposes. */ - -if (dns_find_prefix(dnsa, RESET_ADDITIONAL, chainptr, yptrptr, bits, bitvec)) - return; - -/* No chain records were found in the current DNS response block. Do a new DNS -lookup to try to find these records. This opens up the possibility of DNS -failures. We ignore them at this point; if all branches of the tree fail, there -will be no addresses at the end. */ - -if (dns_lookup(&cdnsa, chainptr, T_A6, NULL) == DNS_SUCCEED) - (void)dns_find_prefix(&cdnsa, RESET_ANSWERS, chainptr, yptrptr, bits, bitvec); -} -#endif /* HAVE_IPV6 && defined(SUPPORT_A6) */ - - /************************************************* @@ -1234,12 +1060,7 @@ dns_address_from_rr(dns_answer *dnsa, dns_record *rr) { dns_address *yield = NULL; -#if HAVE_IPV6 && defined(SUPPORT_A6) -dns_address **yieldptr = &yield; -uschar bitvec[16]; -#else dnsa = dnsa; /* Stop picky compilers warning */ -#endif if (rr->type == T_A) { @@ -1251,14 +1072,6 @@ if (rr->type == T_A) #if HAVE_IPV6 -#ifdef SUPPORT_A6 -else if (rr->type == T_A6) - { - memset(bitvec, 0, sizeof(bitvec)); - dns_complete_a6(&yieldptr, dnsa, rr, 0, bitvec); - } -#endif /* SUPPORT_A6 */ - else { yield = store_get(sizeof(dns_address) + 50);