From 9631eff60862d88667eaa853ebfa3bce1e1cdd8e Mon Sep 17 00:00:00 2001
From: Ainar Garipov <a.garipov@adguard.com>
Date: Fri, 26 Mar 2021 13:03:36 +0300
Subject: [PATCH] Pull request: dnsfilter: imp code, decr cyclo
Updates #2646.
Squashed commit of the following:
commit c153f08bcf5ade4d0fb9b59d2a0e6a21598c4127
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date: Thu Mar 25 21:03:51 2021 +0300
dnsfilter: imp code, decr cyclo
---
internal/dnsfilter/dnsfilter.go | 113 ++++++++++++++++++--------------
scripts/make/go-lint.sh | 13 +++-
2 files changed, 72 insertions(+), 54 deletions(-)
diff --git a/internal/dnsfilter/dnsfilter.go b/internal/dnsfilter/dnsfilter.go
index 73ea3695..0660f7ae 100644
--- a/internal/dnsfilter/dnsfilter.go
+++ b/internal/dnsfilter/dnsfilter.go
@@ -659,6 +659,55 @@ func (d *DNSFilter) matchHostProcessAllowList(host string, dnsres urlfilter.DNSR
return makeResult(rule, NotFilteredAllowList), nil
}
+// matchHostProcessDNSResult processes the matched DNS filtering result.
+func (d *DNSFilter) matchHostProcessDNSResult(
+ qtype uint16,
+ dnsres urlfilter.DNSResult,
+) (res Result) {
+ if dnsres.NetworkRule != nil {
+ reason := FilteredBlockList
+ if dnsres.NetworkRule.Whitelist {
+ reason = NotFilteredAllowList
+ }
+
+ return makeResult(dnsres.NetworkRule, reason)
+ }
+
+ if qtype == dns.TypeA && dnsres.HostRulesV4 != nil {
+ rule := dnsres.HostRulesV4[0]
+ res = makeResult(rule, FilteredBlockList)
+ res.Rules[0].IP = rule.IP.To4()
+
+ return res
+ }
+
+ if qtype == dns.TypeAAAA && dnsres.HostRulesV6 != nil {
+ rule := dnsres.HostRulesV6[0]
+ res = makeResult(rule, FilteredBlockList)
+ res.Rules[0].IP = rule.IP.To16()
+
+ return res
+ }
+
+ if dnsres.HostRulesV4 != nil || dnsres.HostRulesV6 != nil {
+ // Question type doesn't match the host rules. Return the first
+ // matched host rule, but without an IP address.
+ var rule rules.Rule
+ if dnsres.HostRulesV4 != nil {
+ rule = dnsres.HostRulesV4[0]
+ } else if dnsres.HostRulesV6 != nil {
+ rule = dnsres.HostRulesV6[0]
+ }
+
+ res = makeResult(rule, FilteredBlockList)
+ res.Rules[0].IP = net.IP{}
+
+ return res
+ }
+
+ return Result{}
+}
+
// matchHost is a low-level way to check only if hostname is filtered by rules,
// skipping expensive safebrowsing and parental lookups.
func (d *DNSFilter) matchHost(
@@ -697,13 +746,12 @@ func (d *DNSFilter) matchHost(
dnsres, ok := d.filteringEngine.MatchRequest(ureq)
- // Check DNS rewrites first, because the API there is a bit
- // awkward.
+ // Check DNS rewrites first, because the API there is a bit awkward.
if dnsr := dnsres.DNSRewrites(); len(dnsr) > 0 {
res = d.processDNSRewrites(dnsr)
if res.Reason == RewrittenRule && res.CanonName == host {
- // A rewrite of a host to itself. Go on and
- // try matching other things.
+ // A rewrite of a host to itself. Go on and try
+ // matching other things.
} else {
return res, nil
}
@@ -711,55 +759,18 @@ func (d *DNSFilter) matchHost(
return Result{}, nil
}
- if dnsres.NetworkRule != nil {
- log.Debug("Filtering: found rule for host %q: %q list_id: %d",
- host, dnsres.NetworkRule.Text(), dnsres.NetworkRule.GetFilterListID())
- reason := FilteredBlockList
- if dnsres.NetworkRule.Whitelist {
- reason = NotFilteredAllowList
- }
-
- return makeResult(dnsres.NetworkRule, reason), nil
+ res = d.matchHostProcessDNSResult(qtype, dnsres)
+ if len(res.Rules) > 0 {
+ r := res.Rules[0]
+ log.Debug(
+ "filtering: found rule %q for host %q, filter list id: %d",
+ r.Text,
+ host,
+ r.FilterListID,
+ )
}
- if qtype == dns.TypeA && dnsres.HostRulesV4 != nil {
- rule := dnsres.HostRulesV4[0] // note that we process only 1 matched rule
- log.Debug("Filtering: found rule for host %q: %q list_id: %d",
- host, rule.Text(), rule.GetFilterListID())
- res = makeResult(rule, FilteredBlockList)
- res.Rules[0].IP = rule.IP.To4()
-
- return res, nil
- }
-
- if qtype == dns.TypeAAAA && dnsres.HostRulesV6 != nil {
- rule := dnsres.HostRulesV6[0] // note that we process only 1 matched rule
- log.Debug("Filtering: found rule for host %q: %q list_id: %d",
- host, rule.Text(), rule.GetFilterListID())
- res = makeResult(rule, FilteredBlockList)
- res.Rules[0].IP = rule.IP
-
- return res, nil
- }
-
- if dnsres.HostRulesV4 != nil || dnsres.HostRulesV6 != nil {
- // Question Type doesn't match the host rules
- // Return the first matched host rule, but without an IP address
- var rule rules.Rule
- if dnsres.HostRulesV4 != nil {
- rule = dnsres.HostRulesV4[0]
- } else if dnsres.HostRulesV6 != nil {
- rule = dnsres.HostRulesV6[0]
- }
- log.Debug("Filtering: found rule for host %q: %q list_id: %d",
- host, rule.Text(), rule.GetFilterListID())
- res = makeResult(rule, FilteredBlockList)
- res.Rules[0].IP = net.IP{}
-
- return res, nil
- }
-
- return Result{}, nil
+ return res, nil
}
// makeResult returns a properly constructed Result.
diff --git a/scripts/make/go-lint.sh b/scripts/make/go-lint.sh
index ccd21486..95decef7 100644
--- a/scripts/make/go-lint.sh
+++ b/scripts/make/go-lint.sh
@@ -128,6 +128,12 @@ exit_on_output() (
+# Constants
+
+readonly go_files='./main.go ./tools.go ./internal/'
+
+
+
# Checks
exit_on_output blocklist_imports
@@ -142,11 +148,12 @@ golint --set_exit_status ./...
"$GO" vet ./...
-gocyclo --over 19 .
+# Here and below, don't use quotes to get word splitting.
+gocyclo --over 18 $go_files
-gosec --quiet .
+gosec --quiet $go_files
-ineffassign .
+ineffassign ./...
unparam ./...