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+ rewrites: support deeper level wildcards - select the more specific one

This commit is contained in:
Simon Zolin 2020-04-27 17:24:55 +03:00
parent 08b033dd04
commit b33653ec48
3 changed files with 145 additions and 96 deletions
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90
dnsfilter/dnsfilter_test.go
View File

@ -532,96 +532,6 @@ func TestClientSettings(t *testing.T) {
assert.True(t, r.IsFiltered && r.Reason == FilteredBlockedService)
}
func TestRewrites(t *testing.T) {
d := Dnsfilter{}
// CNAME, A, AAAA
d.Rewrites = []RewriteEntry{
RewriteEntry{"somecname", "somehost.com", 0, nil},
RewriteEntry{"somehost.com", "0.0.0.0", 0, nil},
RewriteEntry{"host.com", "1.2.3.4", 0, nil},
RewriteEntry{"host.com", "1.2.3.5", 0, nil},
RewriteEntry{"host.com", "1:2:3::4", 0, nil},
RewriteEntry{"www.host.com", "host.com", 0, nil},
}
d.prepareRewrites()
r := d.processRewrites("host2.com")
assert.Equal(t, NotFilteredNotFound, r.Reason)
r = d.processRewrites("www.host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.Equal(t, "host.com", r.CanonName)
assert.True(t, len(r.IPList) == 3)
assert.True(t, r.IPList[0].Equal(net.ParseIP("1.2.3.4")))
assert.True(t, r.IPList[1].Equal(net.ParseIP("1.2.3.5")))
assert.True(t, r.IPList[2].Equal(net.ParseIP("1:2:3::4")))
// wildcard
d.Rewrites = []RewriteEntry{
RewriteEntry{"host.com", "1.2.3.4", 0, nil},
RewriteEntry{"*.host.com", "1.2.3.5", 0, nil},
}
d.prepareRewrites()
r = d.processRewrites("host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.True(t, r.IPList[0].Equal(net.ParseIP("1.2.3.4")))
r = d.processRewrites("www.host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.True(t, r.IPList[0].Equal(net.ParseIP("1.2.3.5")))
r = d.processRewrites("www.host2.com")
assert.Equal(t, NotFilteredNotFound, r.Reason)
// override a wildcard
d.Rewrites = []RewriteEntry{
RewriteEntry{"a.host.com", "1.2.3.4", 0, nil},
RewriteEntry{"*.host.com", "1.2.3.5", 0, nil},
}
d.prepareRewrites()
r = d.processRewrites("a.host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.True(t, len(r.IPList) == 1)
assert.True(t, r.IPList[0].Equal(net.ParseIP("1.2.3.4")))
// wildcard + CNAME
d.Rewrites = []RewriteEntry{
RewriteEntry{"host.com", "1.2.3.4", 0, nil},
RewriteEntry{"*.host.com", "host.com", 0, nil},
}
d.prepareRewrites()
r = d.processRewrites("www.host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.Equal(t, "host.com", r.CanonName)
assert.True(t, r.IPList[0].Equal(net.ParseIP("1.2.3.4")))
// 2 CNAMEs
d.Rewrites = []RewriteEntry{
RewriteEntry{"b.host.com", "a.host.com", 0, nil},
RewriteEntry{"a.host.com", "host.com", 0, nil},
RewriteEntry{"host.com", "1.2.3.4", 0, nil},
}
d.prepareRewrites()
r = d.processRewrites("b.host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.Equal(t, "host.com", r.CanonName)
assert.True(t, len(r.IPList) == 1)
assert.True(t, r.IPList[0].Equal(net.ParseIP("1.2.3.4")))
// 2 CNAMEs + wildcard
d.Rewrites = []RewriteEntry{
RewriteEntry{"b.host.com", "a.host.com", 0, nil},
RewriteEntry{"a.host.com", "x.somehost.com", 0, nil},
RewriteEntry{"*.somehost.com", "1.2.3.4", 0, nil},
}
d.prepareRewrites()
r = d.processRewrites("b.host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.Equal(t, "x.somehost.com", r.CanonName)
assert.True(t, len(r.IPList) == 1)
assert.True(t, r.IPList[0].Equal(net.ParseIP("1.2.3.4")))
}
func prepareTestDir() string {
const dir = "./agh-test"
_ = os.RemoveAll(dir)

24
dnsfilter/rewrites.go
View File

@ -42,7 +42,10 @@ func (a rewritesArray) Len() int { return len(a) }
func (a rewritesArray) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
// Priority: CNAME, A/AAAA; exact, wildcard.
// Priority:
// . CNAME > A/AAAA;
// . exact > wildcard;
// . higher level wildcard > lower level wildcard
func (a rewritesArray) Less(i, j int) bool {
if a[i].Type == dns.TypeCNAME && a[j].Type != dns.TypeCNAME {
return false
@ -50,13 +53,18 @@ func (a rewritesArray) Less(i, j int) bool {
return true
}
if isWildcard(a[i].Domain) && !isWildcard(a[j].Domain) {
return false
} else if !isWildcard(a[i].Domain) && isWildcard(a[j].Domain) {
return true
if isWildcard(a[i].Domain) {
if !isWildcard(a[j].Domain) {
return false
}
} else {
if isWildcard(a[j].Domain) {
return true
}
}
return i < j
// both are wildcards
return len(a[i].Domain) > len(a[j].Domain)
}
// Prepare entry for use
@ -86,6 +94,7 @@ func (d *Dnsfilter) prepareRewrites() {
// Get the list of matched rewrite entries.
// Priority: CNAME, A/AAAA; exact, wildcard.
// If matched exactly, don't return wildcard entries.
// If matched by several wildcards, select the more specific one
func findRewrites(a []RewriteEntry, host string) []RewriteEntry {
rr := rewritesArray{}
for _, r := range a {
@ -111,7 +120,10 @@ func findRewrites(a []RewriteEntry, host string) []RewriteEntry {
break
}
}
} else {
rr = rr[:1]
}
return rr
}

127
dnsfilter/rewrites_test.go Normal file
View File

@ -0,0 +1,127 @@
package dnsfilter
import (
"net"
"testing"
"github.com/stretchr/testify/assert"
)
func TestRewrites(t *testing.T) {
d := Dnsfilter{}
// CNAME, A, AAAA
d.Rewrites = []RewriteEntry{
RewriteEntry{"somecname", "somehost.com", 0, nil},
RewriteEntry{"somehost.com", "0.0.0.0", 0, nil},
RewriteEntry{"host.com", "1.2.3.4", 0, nil},
RewriteEntry{"host.com", "1.2.3.5", 0, nil},
RewriteEntry{"host.com", "1:2:3::4", 0, nil},
RewriteEntry{"www.host.com", "host.com", 0, nil},
}
d.prepareRewrites()
r := d.processRewrites("host2.com")
assert.Equal(t, NotFilteredNotFound, r.Reason)
r = d.processRewrites("www.host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.Equal(t, "host.com", r.CanonName)
assert.True(t, len(r.IPList) == 3)
assert.True(t, r.IPList[0].Equal(net.ParseIP("1.2.3.4")))
assert.True(t, r.IPList[1].Equal(net.ParseIP("1.2.3.5")))
assert.True(t, r.IPList[2].Equal(net.ParseIP("1:2:3::4")))
// wildcard
d.Rewrites = []RewriteEntry{
RewriteEntry{"host.com", "1.2.3.4", 0, nil},
RewriteEntry{"*.host.com", "1.2.3.5", 0, nil},
}
d.prepareRewrites()
r = d.processRewrites("host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.True(t, r.IPList[0].Equal(net.ParseIP("1.2.3.4")))
r = d.processRewrites("www.host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.True(t, r.IPList[0].Equal(net.ParseIP("1.2.3.5")))
r = d.processRewrites("www.host2.com")
assert.Equal(t, NotFilteredNotFound, r.Reason)
// override a wildcard
d.Rewrites = []RewriteEntry{
RewriteEntry{"a.host.com", "1.2.3.4", 0, nil},
RewriteEntry{"*.host.com", "1.2.3.5", 0, nil},
}
d.prepareRewrites()
r = d.processRewrites("a.host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.True(t, len(r.IPList) == 1)
assert.True(t, r.IPList[0].Equal(net.ParseIP("1.2.3.4")))
// wildcard + CNAME
d.Rewrites = []RewriteEntry{
RewriteEntry{"host.com", "1.2.3.4", 0, nil},
RewriteEntry{"*.host.com", "host.com", 0, nil},
}
d.prepareRewrites()
r = d.processRewrites("www.host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.Equal(t, "host.com", r.CanonName)
assert.True(t, r.IPList[0].Equal(net.ParseIP("1.2.3.4")))
// 2 CNAMEs
d.Rewrites = []RewriteEntry{
RewriteEntry{"b.host.com", "a.host.com", 0, nil},
RewriteEntry{"a.host.com", "host.com", 0, nil},
RewriteEntry{"host.com", "1.2.3.4", 0, nil},
}
d.prepareRewrites()
r = d.processRewrites("b.host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.Equal(t, "host.com", r.CanonName)
assert.True(t, len(r.IPList) == 1)
assert.True(t, r.IPList[0].Equal(net.ParseIP("1.2.3.4")))
// 2 CNAMEs + wildcard
d.Rewrites = []RewriteEntry{
RewriteEntry{"b.host.com", "a.host.com", 0, nil},
RewriteEntry{"a.host.com", "x.somehost.com", 0, nil},
RewriteEntry{"*.somehost.com", "1.2.3.4", 0, nil},
}
d.prepareRewrites()
r = d.processRewrites("b.host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.Equal(t, "x.somehost.com", r.CanonName)
assert.True(t, len(r.IPList) == 1)
assert.True(t, r.IPList[0].Equal(net.ParseIP("1.2.3.4")))
}
func TestRewritesLevels(t *testing.T) {
d := Dnsfilter{}
// exact host, wildcard L2, wildcard L3
d.Rewrites = []RewriteEntry{
RewriteEntry{"host.com", "1.1.1.1", 0, nil},
RewriteEntry{"*.host.com", "2.2.2.2", 0, nil},
RewriteEntry{"*.sub.host.com", "3.3.3.3", 0, nil},
}
d.prepareRewrites()
// match exact
r := d.processRewrites("host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.Equal(t, 1, len(r.IPList))
assert.Equal(t, "1.1.1.1", r.IPList[0].String())
// match L2
r = d.processRewrites("sub.host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.Equal(t, 1, len(r.IPList))
assert.Equal(t, "2.2.2.2", r.IPList[0].String())
// match L3
r = d.processRewrites("my.sub.host.com")
assert.Equal(t, ReasonRewrite, r.Reason)
assert.Equal(t, 1, len(r.IPList))
assert.Equal(t, "3.3.3.3", r.IPList[0].String())
}