From 20078efc75d1de918078163bfa36dd8935428233 Mon Sep 17 00:00:00 2001 Message-Id: <20078efc75d1de918078163bfa36dd8935428233.1716264040.git.mdw@distorted.org.uk> From: Mark Wooding Date: Wed, 14 May 2014 00:03:43 +0100 Subject: [PATCH] New init flags and options to influence address family selection. Organization: Straylight/Edgeware From: Mark Wooding --- src/adns.h | 24 +++++++++++++++++++++++- src/setup.c | 13 +++++++++++++ src/types.c | 12 ++++++++++++ 3 files changed, 48 insertions(+), 1 deletion(-) diff --git a/src/adns.h b/src/adns.h index 267fd6e..e5063b7 100644 --- a/src/adns.h +++ b/src/adns.h @@ -104,7 +104,18 @@ typedef enum { /* In general, or together the desired flags: */ adns_if_eintr= 0x0020,/* allow _wait and _synchronous to return EINTR */ adns_if_nosigpipe= 0x0040,/* applic has SIGPIPE ignored, do not protect */ adns_if_checkc_entex=0x0100,/* consistency checks on entry/exit to adns fns */ - adns_if_checkc_freq= 0x0300 /* consistency checks very frequently (slow!) */ + adns_if_checkc_freq= 0x0300,/* consistency checks very frequently (slow!) */ + + adns_if_af_v4only= 0x0400,/* only return IPv4 addresses, given the choice */ + adns_if_af_v6only= 0x0800,/* only return IPv6 addresses, ... */ + adns_if_afmask= adns_if_af_v4only|adns_if_af_v6only + /* Only set one of these. They are policy flags, and overridden by the + * adns_af:... options in resolv.conf. If the adns_qf_ipv... query + * flags are incompatible with these settings (in the sense that no + * address families are permitted at all) then the query flags take + * precedence; otherwise only records which satisfy all of the stated + * requirements are allowed. + */ } adns_initflags; typedef enum { /* In general, or together the desired flags: */ @@ -555,6 +566,17 @@ int adns_init_logfn(adns_state *newstate_r, adns_initflags flags, * Changes the consistency checking frequency; this overrides the * setting of adns_if_check_entex, adns_if_check_freq, or neither, * in the flags passed to adns_init. + * + * adns_af:v4only + * adns_af:v6only + * adns_af:any + * Controls whether ADNS looks for IPv4 (A records) and IPv6 (AAAA + * records) addresses when it's trying to build a socket address. + * The default is `any' which means to allow both. The `sortlist' + * directive can be used to control the relative preference of IPv4 + * and IPv6 addresses if both are returned for the same query. + * These override the corresponding init flags (covered by + * adns_if_afmask). * * There are a number of environment variables which can modify the * behaviour of adns. They take effect only if adns_init is used, and diff --git a/src/setup.c b/src/setup.c index 67dcd1a..a264d15 100644 --- a/src/setup.c +++ b/src/setup.c @@ -310,6 +310,19 @@ static void ccf_options(adns_state ads, const char *fn, } continue; } + if (l>=8 && !memcmp(word,"adns_af:",8)) { + if (!strcmp(word+8,"v4only")) + ads->iflags = (ads->iflags & ~adns_if_afmask) | adns_if_af_v4only; + else if (!strcmp(word+8,"v6only")) + ads->iflags = (ads->iflags & ~adns_if_afmask) | adns_if_af_v6only; + else if (!strcmp(word+8,"any")) + ads->iflags = (ads->iflags & ~adns_if_afmask); + else { + configparseerr(ads,fn,lno, "option adns_af has bad value `%s' " + "(must be any, v4only or v6only", word+8); + } + continue; + } adns__diag(ads,-1,0,"%s:%d: unknown option `%.*s'", fn,lno, l,word); } } diff --git a/src/types.c b/src/types.c index 582ddb5..11f9fd4 100644 --- a/src/types.c +++ b/src/types.c @@ -485,9 +485,21 @@ static void addr_rrtypes(adns_state ads, adns_rrtype type, { size_t n = 0; adns_rrtype qtf = type & adns__qtf_deref; + adns_queryflags permitaf = 0, hackaf = 0; if (!(type & adns__qtf_bigaddr) || !(type & adns__qtf_manyaf)) qf = (qf & adns__qf_afmask) | adns_qf_ipv4_only; + else if (ads->iflags & adns_if_afmask) { + if (ads->iflags & adns_if_af_v4only) { + permitaf |= adns_qf_ipv4_only; + hackaf |= adns_qf_domapv4; + } + if (ads->iflags & adns_if_af_v6only) + permitaf |= adns_qf_ipv6_only; + if (qf & permitaf) + qf &= hackaf | permitaf | ~adns__qf_afmask; + } + if (qf & adns_qf_ipv4_only) rrty[n++] = adns_r_a | qtf; if (qf & adns_qf_ipv6_only) rrty[n++] = adns_r_aaaa | qtf; -- [mdw]