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Merge: + dns rewrites: support wildcard override

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Close #922

Squashed commit of the following:

commit 8ab742d84916a02043989fcfa5fc258e84046205
Merge: 2abde92f e398117d
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Thu Jan 16 12:47:44 2020 +0300

    Merge remote-tracking branch 'origin/master' into 922-rewrites

commit 2abde92fe2d1bdb153787b4ecac60f9744c7fd1a
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Thu Jan 16 12:34:41 2020 +0300

    minor

commit 3c20579cde85967786830d2d1b87cd987fc2ae12
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Fri Jan 10 19:06:53 2020 +0300

    don't change the order of rewrite entry list (apply priority at runtime)

commit 4f658f98011a7e31852c0ce379f2a02738f5614f
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Tue Dec 31 15:21:50 2019 +0300

    minor

commit 9e56b4f3abefe3ff1d19bc61375f31dc55242e52
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Tue Dec 31 15:14:14 2019 +0300

    * remove unused code

commit 4178f025a388eb768914306efa91ffead87e5a0c
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Tue Dec 31 15:13:57 2019 +0300

    + dns rewrites: support wildcard override
This commit is contained in:
Simon Zolin
2020-01-16 12:51:35 +03:00
parent e398117d25
commit a6d7511806
4 changed files with 195 additions and 136 deletions
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88
dnsfilter/dnsfilter.go
View File

@@ -34,15 +34,8 @@ type RequestFilteringSettings struct {
ServicesRules []ServiceEntry
}
// RewriteEntry is a rewrite array element
type RewriteEntry struct {
Domain string `yaml:"domain"`
Answer string `yaml:"answer"` // IP address or canonical name
}
// Config allows you to configure DNS filtering with New() or just change variables directly.
type Config struct {
ParentalSensitivity int `yaml:"parental_sensitivity"` // must be either 3, 10, 13 or 17
ParentalEnabled bool `yaml:"parental_enabled"`
SafeSearchEnabled bool `yaml:"safesearch_enabled"`
SafeBrowsingEnabled bool `yaml:"safebrowsing_enabled"`
@@ -175,7 +168,10 @@ func (d *Dnsfilter) GetConfig() RequestFilteringSettings {
// WriteDiskConfig - write configuration
func (d *Dnsfilter) WriteDiskConfig(c *Config) {
d.confLock.Lock()
*c = d.Config
c.Rewrites = rewriteArrayDup(d.Config.Rewrites)
d.confLock.Unlock()
}
// SetFilters - set new filters (synchronously or asynchronously)
@@ -343,17 +339,11 @@ func (d *Dnsfilter) CheckHost(host string, qtype uint16, setts *RequestFiltering
return Result{}, nil
}
// Return TRUE of host name matches a wildcard pattern
func matchDomainWildcard(host, wildcard string) bool {
return len(wildcard) >= 2 &&
wildcard[0] == '*' && wildcard[1] == '.' &&
strings.HasSuffix(host, wildcard[1:])
}
// Process rewrites table
// . Find CNAME for a domain name
// . Find CNAME for a domain name (exact match or by wildcard)
// . if found, set domain name to canonical name
// . Find A or AAAA record for a domain name
// . repeat for the new domain name (Note: we return only the last CNAME)
// . Find A or AAAA record for a domain name (exact match or by wildcard)
// . if found, return IP addresses
func (d *Dnsfilter) processRewrites(host string, qtype uint16) Result {
var res Result
@@ -361,50 +351,33 @@ func (d *Dnsfilter) processRewrites(host string, qtype uint16) Result {
d.confLock.RLock()
defer d.confLock.RUnlock()
for _, r := range d.Rewrites {
if r.Domain != host {
if !matchDomainWildcard(host, r.Domain) {
continue
}
}
ip := net.ParseIP(r.Answer)
if ip == nil {
log.Debug("Rewrite: CNAME for %s is %s", host, r.Answer)
host = r.Answer
res.CanonName = r.Answer
res.Reason = ReasonRewrite
break
}
}
for _, r := range d.Rewrites {
if r.Domain != host {
if !matchDomainWildcard(host, r.Domain) {
continue
}
}
ip := net.ParseIP(r.Answer)
if ip == nil {
continue
}
ip4 := ip.To4()
if qtype == dns.TypeA && ip4 != nil {
res.IPList = append(res.IPList, ip4)
log.Debug("Rewrite: A for %s is %s", host, ip4)
} else if qtype == dns.TypeAAAA && ip4 == nil {
res.IPList = append(res.IPList, ip)
log.Debug("Rewrite: AAAA for %s is %s", host, ip)
}
}
if len(res.IPList) != 0 {
rr := findRewrites(d.Rewrites, host)
if len(rr) != 0 {
res.Reason = ReasonRewrite
}
cnames := map[string]bool{}
origHost := host
for len(rr) != 0 && rr[0].Type == dns.TypeCNAME {
log.Debug("Rewrite: CNAME for %s is %s", host, rr[0].Answer)
host = rr[0].Answer
_, ok := cnames[host]
if ok {
log.Info("Rewrite: breaking CNAME redirection loop: %s. Question: %s", host, origHost)
return res
}
cnames[host] = false
res.CanonName = rr[0].Answer
rr = findRewrites(d.Rewrites, host)
}
for _, r := range rr {
if r.Type != dns.TypeCNAME && r.Type == qtype {
res.IPList = append(res.IPList, r.IP)
log.Debug("Rewrite: A/AAAA for %s is %s", host, r.IP)
}
}
return res
}
@@ -592,6 +565,7 @@ func New(c *Config, filters map[int]string) *Dnsfilter {
if c != nil {
d.Config = *c
d.prepareRewrites()
}
if filters != nil {