diff options
| -rw-r--r-- | doc/doc-misc/WishList | 9 | ||||
| -rw-r--r-- | doc/doc-txt/ChangeLog | 14 | ||||
| -rw-r--r-- | doc/doc-txt/NewStuff | 39 | ||||
| -rw-r--r-- | src/src/lookups/dnsdb.c | 241 |
4 files changed, 204 insertions, 99 deletions
diff --git a/doc/doc-misc/WishList b/doc/doc-misc/WishList index d3ce50b98..aa9fb7b2b 100644 --- a/doc/doc-misc/WishList +++ b/doc/doc-misc/WishList @@ -1,4 +1,4 @@ -$Cambridge: exim/doc/doc-misc/WishList,v 1.6 2004/11/09 09:32:58 ph10 Exp $ +$Cambridge: exim/doc/doc-misc/WishList,v 1.7 2004/11/19 15:18:57 ph10 Exp $ EXIM 4 WISH LIST ---------------- @@ -1413,13 +1413,6 @@ be able to set variables in routers like in acl's." This is effectively a radical suggestion for a complete re-design, and is therefore BIG. ------------------------------------------------------------------------------ -(222) 19-Dec-03 S Iterative option for dnsdb - -A way of getting a dnsdb lookup to chop off components until something is -found: e.g. ${lookup dndsb-i{ns=a.b.c.d}} would look for nameservers for -a.b.c.d, then b.c.d, etc. ------------------------------------------------------------------------------- - (223) 22-Dec-03 S Support SOA lookup in dnsdb lookups ------------------------------------------------------------------------------ diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog index 5e213d772..1def41364 100644 --- a/doc/doc-txt/ChangeLog +++ b/doc/doc-txt/ChangeLog @@ -1,4 +1,4 @@ -$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.34 2004/11/19 09:45:54 ph10 Exp $ +$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.35 2004/11/19 15:18:57 ph10 Exp $ Change log file for Exim from version 4.21 ------------------------------------------- @@ -149,8 +149,16 @@ Exim version 4.44 per-process caching. But the chance of anyone hitting this buglet seems very small. -37. The dnsdb lookup has a new type, "zns", which walks up the domain tree - until it finds some nameserver records. It should be used with care. +37. The dnsdb lookup has been extended in a number of ways. + + (1) There is a new type, "zns", which walks up the domain tree until it + finds some nameserver records. It should be used with care. + + (2) It is now possible to give a list of domains (or IP addresses) to be + looked up. + + (3) It is now possible to specify the separator character for use when + multiple records are returned. Exim version 4.43 diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff index ee9f55c31..810607a5b 100644 --- a/doc/doc-txt/NewStuff +++ b/doc/doc-txt/NewStuff @@ -1,4 +1,4 @@ -$Cambridge: exim/doc/doc-txt/NewStuff,v 1.12 2004/11/19 09:45:54 ph10 Exp $ +$Cambridge: exim/doc/doc-txt/NewStuff,v 1.13 2004/11/19 15:18:57 ph10 Exp $ New Features in Exim -------------------- @@ -129,6 +129,43 @@ Version 4.44 the name servers for the high-level domains such as .com or .co.uk are not going to be on such a list. +13. It is now possible to specify a list of domains or IP addresses to be + looked up in a dnsdb lookup. The list is specified in the normal Exim way, + with colon as the default separator, but with the ability to change this. + For example: + + ${lookup dnsdb{one.domain.com:two.domain.com}} + ${lookup dnsdb{a=one.host.com:two.host.com}} + ${lookup dnsdb{ptr = <; 1.2.3.4 ; 4.5.6.8}} + + In order to retain backwards compatibility, there is one special case: if + the lookup type is PTR and no change of separator is specified, Exim looks + to see if the rest of the string is precisely one IPv6 address. In this + case, it does not treat it as a list. + + The data from each lookup is concatenated, with newline separators (by + default - see 14 below), in the same way that multiple DNS records for a + single item are handled. + + The lookup fails only if all the DNS lookups fail. As long as at least one + of them yields some data, the lookup succeeds. However, if there is a + temporary DNS error for any of them, the lookup defers. + +14. It is now possible to specify the character to be used as a separator when + a dnsdb lookup returns data from more than one DNS record. The default is a + newline. To specify a different character, put '>' followed by the new + character at the start of the query. For example: + + ${lookup dnsdb{>: a=h1.test.ex:h2.test.ex}} + ${lookup dnsdb{>| mx=<;m1.test.ex;m2.test.ex}} + + It is permitted to specify a space as the separator character. Note that + more than one DNS record can be found for a single lookup item; this + feature is relevant even when you do not specify a list. + + The same effect could be achieved by wrapping the lookup in ${tr...}; this + feature is just a syntactic simplification. + Version 4.43 ------------ diff --git a/src/src/lookups/dnsdb.c b/src/src/lookups/dnsdb.c index 492e53574..22a9de4f4 100644 --- a/src/src/lookups/dnsdb.c +++ b/src/src/lookups/dnsdb.c @@ -1,4 +1,4 @@ -/* $Cambridge: exim/src/src/lookups/dnsdb.c,v 1.2 2004/11/19 09:45:54 ph10 Exp $ */ +/* $Cambridge: exim/src/src/lookups/dnsdb.c,v 1.3 2004/11/19 15:18:57 ph10 Exp $ */ /************************************************* * Exim - an Internet mail transport agent * @@ -77,7 +77,20 @@ return (void *)(-1); /* Any non-0 value */ * Find entry point for dnsdb * *************************************************/ -/* See local README for interface description. */ +/* See local README for interface description. The query in the "keystring" may +consist of a number of parts. + +(a) If the first significant character is '>' then the next character is the +separator character that is used when multiple records are found. The default +separator is newline. + +(b) If the next sequence of characters is a sequence of letters and digits +followed by '=', it is interpreted as the name of the DNS record type. The +default is "A". + +(c) Then there follows list of domain names. This is a generalized Exim list, +which may start with '<' in order to set a specific separator. The default +separator, as always, is colon. */ int dnsdb_find(void *handle, uschar *filename, uschar *keystring, int length, @@ -86,9 +99,10 @@ dnsdb_find(void *handle, uschar *filename, uschar *keystring, int length, int rc; int size = 256; int ptr = 0; +int sep = 0; int type = T_TXT; -uschar *orig_keystring = keystring; -uschar *equals = Ustrchr(keystring, '='); +uschar *outsep = US"\n"; +uschar *equals, *domain; uschar buffer[256]; /* Because we're the working in the search pool, we try to reclaim as much @@ -105,12 +119,26 @@ filename = filename; length = length; do_cache = do_cache; -/* If the keystring contains an = this is preceded by a type name. */ +/* If the string starts with '>' we change the output separator */ -if (equals != NULL) +while (isspace(*keystring)) keystring++; +if (*keystring == '>') { - int i; - int len = equals - keystring; + outsep = keystring + 1; + keystring += 2; + while (isspace(*keystring)) keystring++; + } + +/* If the keystring contains an = this must be preceded by a valid type name. */ + +if ((equals = Ustrchr(keystring, '=')) != NULL) + { + int i, len; + uschar *tend = equals; + + while (tend > keystring && isspace(tend[-1])) tend--; + len = tend - keystring; + for (i = 0; i < sizeof(type_names)/sizeof(uschar *); i++) { if (len == Ustrlen(type_names[i]) && @@ -120,111 +148,150 @@ if (equals != NULL) break; } } + if (i >= sizeof(type_names)/sizeof(uschar *)) { *errmsg = US"unsupported DNS record type"; return DEFER; } - keystring += len + 1; + + keystring = equals + 1; + while (isspace(*keystring)) keystring++; } - -/* If the type is PTR, we have to construct the relevant magic lookup -key. This code is now in a separate function. */ - -if (type == T_PTR) - { - dns_build_reverse(keystring, buffer); - keystring = buffer; - } - -DEBUG(D_lookup) debug_printf("dnsdb key: %s\n", keystring); - -/* Initialize the resolver, in case this is the first time it is used -in this run. Then do the lookup and sort out the result. */ + +/* Initialize the resolver in case this is the first time it has been used. */ dns_init(FALSE, FALSE); -rc = dns_special_lookup(&dnsa, keystring, type, NULL); -if (rc == DNS_NOMATCH || rc == DNS_NODATA) return FAIL; -if (rc != DNS_SUCCEED) return DEFER; +/* The remainder of the string must be a list of domains. As long as the lookup +for at least one of them succeeds, we return success. Failure means that none +of them were found. -/* If the lookup was a pseudo-type, change it to the correct type for searching -the returned records; then search for them. */ +The original implementation did not support a list of domains. Adding the list +feature is compatible, except in one case: when PTR records are being looked up +for a single IPv6 address. Fortunately, we can hack in a compatibility feature +here: If the type is PTR and no list separator is specified, and the entire +remaining string is valid as an IP address, set an impossible separator so that +it is treated as one item. */ -if (type == T_ZNS) type = T_NS; -for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); - rr != NULL; - rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) - { - if (rr->type != type) continue; +if (type == T_PTR && keystring[0] != '<' && + string_is_ip_address(keystring, NULL) > 0) + sep = -1; - /* There may be several addresses from an A6 record. Put newlines between - them, just as for between several records. */ +/* Now scan the list and do a lookup for each item */ - if (type == T_A || - #ifdef SUPPORT_A6 - type == T_A6 || - #endif - type == T_AAAA) - { - dns_address *da; - for (da = dns_address_from_rr(&dnsa, rr); da != NULL; da = da->next) - { - if (ptr != 0) yield = string_cat(yield, &size, &ptr, US"\n", 1); - yield = string_cat(yield, &size, &ptr, da->address, Ustrlen(da->address)); - } - continue; - } - - /* Other kinds of record just have one piece of data each. */ +while ((domain = string_nextinlist(&keystring, &sep, buffer, sizeof(buffer))) + != NULL) + { + uschar rbuffer[256]; - if (ptr != 0) yield = string_cat(yield, &size, &ptr, US"\n", 1); - - if (type == T_TXT) + /* If the type is PTR, we have to construct the relevant magic lookup + key. This code is now in a separate function. */ + + if (type == T_PTR) { - yield = string_cat(yield, &size, &ptr, (uschar *)(rr->data+1), - (rr->data)[0]); + dns_build_reverse(domain, rbuffer); + domain = rbuffer; } - else /* T_CNAME, T_MX, T_NS, T_PTR */ + + DEBUG(D_lookup) debug_printf("dnsdb key: %s\n", domain); + + /* Do the lookup and sort out the result. We use the special + lookup function that knows about pseudo types like "zns". If the lookup + fails, continue with the next domain. */ + + rc = dns_special_lookup(&dnsa, domain, type, NULL); + + if (rc == DNS_NOMATCH || rc == DNS_NODATA) continue; + if (rc != DNS_SUCCEED) return DEFER; + + /* If the lookup was a pseudo-type, change it to the correct type for + searching the returned records; then search for them. */ + + if (type == T_ZNS) type = T_NS; + for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); + rr != NULL; + rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) { - uschar s[264]; - uschar *p = (uschar *)(rr->data); - if (type == T_MX) + if (rr->type != type) continue; + + /* There may be several addresses from an A6 record. Put the configured + separator between them, just as for between several records. However, A6 + support is not normally configured these days. */ + + if (type == T_A || + #ifdef SUPPORT_A6 + type == T_A6 || + #endif + type == T_AAAA) { - int num; - GETSHORT(num, p); /* pointer is advanced */ - sprintf(CS s, "%d ", num); - yield = string_cat(yield, &size, &ptr, s, Ustrlen(s)); + dns_address *da; + for (da = dns_address_from_rr(&dnsa, rr); da != NULL; da = da->next) + { + if (ptr != 0) yield = string_cat(yield, &size, &ptr, outsep, 1); + yield = string_cat(yield, &size, &ptr, da->address, + Ustrlen(da->address)); + } + continue; } - else if (type == T_SRV) + + /* Other kinds of record just have one piece of data each, but there may be + several of them, of course. */ + + if (ptr != 0) yield = string_cat(yield, &size, &ptr, outsep, 1); + + if (type == T_TXT) { - int num, weight, port; - GETSHORT(num, p); /* pointer is advanced */ - GETSHORT(weight, p); - GETSHORT(port, p); - sprintf(CS s, "%d %d %d ", num, weight, port); - yield = string_cat(yield, &size, &ptr, s, Ustrlen(s)); + yield = string_cat(yield, &size, &ptr, (uschar *)(rr->data+1), + (rr->data)[0]); } - rc = dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, p, - (DN_EXPAND_ARG4_TYPE)(s), sizeof(s)); - - /* If an overlong response was received, the data will have been - truncated and dn_expand may fail. */ - - if (rc < 0) + else /* T_CNAME, T_MX, T_NS, T_SRV, T_PTR */ { - log_write(0, LOG_MAIN, "host name alias list truncated for %s", - orig_keystring); - break; + uschar s[264]; + uschar *p = (uschar *)(rr->data); + if (type == T_MX) + { + int num; + GETSHORT(num, p); /* pointer is advanced */ + sprintf(CS s, "%d ", num); + yield = string_cat(yield, &size, &ptr, s, Ustrlen(s)); + } + else if (type == T_SRV) + { + int num, weight, port; + GETSHORT(num, p); /* pointer is advanced */ + GETSHORT(weight, p); + GETSHORT(port, p); + sprintf(CS s, "%d %d %d ", num, weight, port); + yield = string_cat(yield, &size, &ptr, s, Ustrlen(s)); + } + rc = dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, p, + (DN_EXPAND_ARG4_TYPE)(s), sizeof(s)); + + /* If an overlong response was received, the data will have been + truncated and dn_expand may fail. */ + + if (rc < 0) + { + log_write(0, LOG_MAIN, "host name alias list truncated: type=%s " + "domain=%s", dns_text_type(type), domain); + break; + } + else yield = string_cat(yield, &size, &ptr, s, Ustrlen(s)); } - else yield = string_cat(yield, &size, &ptr, s, Ustrlen(s)); - } - } + } /* Loop for list of returned records */ + } /* Loop for list of domains */ + +/* Reclaim unused memory */ +store_reset(yield + ptr + 1); + +/* If ptr == 0 we have not found anything. Otherwise, insert the terminating +zero and return the result. */ + +if (ptr == 0) return FAIL; yield[ptr] = 0; -store_reset(yield + ptr + 1); /* Reclaim unused */ *result = yield; - return OK; } |