From ff4dbb191fab3d0bc10b82bb6d59898d03c2b50d Mon Sep 17 00:00:00 2001 From: Philip Hazel Date: Mon, 20 Dec 2004 15:24:27 +0000 Subject: [PATCH] Added Tony's defer_foo patch to dnsdb lookups. --- doc/doc-txt/ChangeLog | 5 ++-- doc/doc-txt/NewStuff | 20 ++++++++++++--- src/ACKNOWLEDGMENTS | 3 ++- src/src/lookups/dnsdb.c | 54 ++++++++++++++++++++++++++++++++++++----- 4 files changed, 69 insertions(+), 13 deletions(-) diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog index 6774dad4a..a12145aeb 100644 --- a/doc/doc-txt/ChangeLog +++ b/doc/doc-txt/ChangeLog @@ -1,4 +1,4 @@ -$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.46 2004/12/20 14:57:05 ph10 Exp $ +$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.47 2004/12/20 15:24:27 ph10 Exp $ Change log file for Exim from version 4.21 ------------------------------------------- @@ -157,7 +157,8 @@ Exim version 4.50 just the host names, not the priorities. (3) It is now possible to give a list of domains (or IP addresses) to be - looked up. + looked up. The behaviour when one of the lookups defers can be + controlled by a keyword. (4) It is now possible to specify the separator character for use when multiple records are returned. diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff index 16c9c4653..3109ea96f 100644 --- a/doc/doc-txt/NewStuff +++ b/doc/doc-txt/NewStuff @@ -1,4 +1,4 @@ -$Cambridge: exim/doc/doc-txt/NewStuff,v 1.20 2004/12/17 14:52:44 ph10 Exp $ +$Cambridge: exim/doc/doc-txt/NewStuff,v 1.21 2004/12/20 15:24:27 ph10 Exp $ New Features in Exim -------------------- @@ -152,9 +152,21 @@ Version 4.50 single item are handled. The dnsdb lookup fails only if all the DNS lookups fail. If there is a - temporary DNS error for any of them, the remaining lookups are still done, - and only if none of them succeed does the dnsdb lookup defer. As long as at - least one of the DNS lookups yields some data, the dnsdb lookup succeeds. + temporary DNS error for any of them, the behaviour is controlled by + an optional keyword followed by a comma that may appear before the record + type. The possible keywords are "defer_strict", "defer_never", and + "defer_lax". With "strict" behaviour, any temporary DNS error causes the + whole lookup to defer. With "never" behaviour, a temporary DNS error is + ignored, and the behaviour is as if the DNS lookup failed to find anything. + With "lax" behaviour, all the queries are attempted, but a temporary DNS + error causes the whole lookup to defer only if none of the other lookups + succeed. The default is "lax", so the following lookups are equivalent: + + ${lookup dnsdb{defer_lax,a=one.host.com:two.host.com}} + ${lookup dnsdb{a=one.host.com:two.host.com}} + + Thus, in the default case, as long as at least one of the DNS lookups + yields some data, the dnsdb lookup succeeds. 15. It is now possible to specify the character to be used as a separator when a dnsdb lookup returns data from more than one DNS record. The default is a diff --git a/src/ACKNOWLEDGMENTS b/src/ACKNOWLEDGMENTS index a914262c7..3c591fb9c 100644 --- a/src/ACKNOWLEDGMENTS +++ b/src/ACKNOWLEDGMENTS @@ -1,4 +1,4 @@ -$Cambridge: exim/src/ACKNOWLEDGMENTS,v 1.8 2004/12/20 14:57:05 ph10 Exp $ +$Cambridge: exim/src/ACKNOWLEDGMENTS,v 1.9 2004/12/20 15:24:28 ph10 Exp $ EXIM ACKNOWLEDGEMENTS @@ -123,6 +123,7 @@ Tony Finch Expansion extensions Patch for more daemon exiwhat information Patch for -dd Patch for mxh lookup type in dnsdb + Patch for defer_foo in dndsb Giuliano Gavazzi Patches for OSX compilation Dominic Germain Patch for exiqgrep MacOS X bug Oliver Gorwits $load_average patch diff --git a/src/src/lookups/dnsdb.c b/src/src/lookups/dnsdb.c index 3f9dc8e78..9cd8612b1 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 1.5 2004/11/25 14:31:28 ph10 Exp $ */ +/* $Cambridge: exim/src/src/lookups/dnsdb.c,v 1.6 2004/12/20 15:24:28 ph10 Exp $ */ /************************************************* * Exim - an Internet mail transport agent * @@ -86,11 +86,17 @@ consist of a number of parts. 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 +(b) If the next sequence of characters is 'defer_FOO' followed by a comma, +the defer behaviour is set to FOO. The possible behaviours are: 'strict', where +any defer causes the whole lookup to defer; 'lax', where a defer causes the +whole lookup to defer only if none of the DNS queries succeeds; and 'never', +where all defers are as if the lookup failed. The default is 'lax'. + +(c) 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". +default is "TXT". -(c) Then there follows list of domain names. This is a generalized Exim list, +(d) 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. */ @@ -102,6 +108,7 @@ int rc; int size = 256; int ptr = 0; int sep = 0; +int defer_mode = PASS; int type = T_TXT; int failrc = FAIL; uschar *outsep = US"\n"; @@ -132,6 +139,40 @@ if (*keystring == '>') while (isspace(*keystring)) keystring++; } +/* Check for a defer behaviour keyword. */ + +if (strncmpic(keystring, US"defer_", 6) == 0) + { + keystring += 6; + if (strncmpic(keystring, US"strict", 6) == 0) + { + defer_mode = DEFER; + keystring += 6; + } + else if (strncmpic(keystring, US"lax", 3) == 0) + { + defer_mode = PASS; + keystring += 3; + } + else if (strncmpic(keystring, US"never", 5) == 0) + { + defer_mode = OK; + keystring += 5; + } + else + { + *errmsg = US"unsupported dnsdb defer behaviour"; + return DEFER; + } + while (isspace(*keystring)) keystring++; + if (*keystring++ != ',') + { + *errmsg = US"dnsdb defer behaviour syntax error"; + return DEFER; + } + while (isspace(*keystring)) keystring++; + } + /* If the keystring contains an = this must be preceded by a valid type name. */ if ((equals = Ustrchr(keystring, '=')) != NULL) @@ -214,8 +255,9 @@ while ((domain = string_nextinlist(&keystring, &sep, buffer, sizeof(buffer))) if (rc == DNS_NOMATCH || rc == DNS_NODATA) continue; if (rc != DNS_SUCCEED) { - failrc = DEFER; - continue; + if (defer_mode == DEFER) return DEFER; /* always defer */ + else if (defer_mode == PASS) failrc = DEFER; /* defer only if all do */ + continue; /* treat defer as fail */ } /* Search the returned records */ -- 2.30.2