TrueCloudLab/coredns
16
0
Fork 2
Code Issues Pull requests 1 Projects Releases Packages Wiki Activity Actions

CIDR query routing (#1159)

Browse source 
* core: allow all CIDR ranges in zone specifications

Allow (e.g.) a v4 reverse on a /17. If a zone is specified in such a
way a FilterFunc is set in the config. This filter is checked against
incoming queries.

For all other queries this adds a 'x != nil' check which will not impact
performace too much. Benchmark function is added as well to check for
this as wel.

Add multiple tests in tests/server_reverse_test.go.

Benchmark shows in the non-reverse case this hardly impact the speed:

~~~
classless:
pkg: github.com/coredns/coredns/core/dnsserver
BenchmarkCoreServeDNS-4   	 1000000	      1431 ns/op	      16 B/op	       1 allocs/op

pkg: github.com/coredns/coredns/core/dnsserver
BenchmarkCoreServeDNS-4   	 1000000	      1429 ns/op	      16 B/op	       1 allocs/op

master:
pkg: github.com/coredns/coredns/core/dnsserver
BenchmarkCoreServeDNS-4   	 1000000	      1412 ns/op	      16 B/op	       1 allocs/op

pkg: github.com/coredns/coredns/core/dnsserver
BenchmarkCoreServeDNS-4   	 1000000	      1429 ns/op	      16 B/op	       1 allocs/op
~~~

* README.md updates
This commit is contained in:
Miek Gieben 2017-10-24 10:16:03 +01:00 • committed by GitHub
parent 5f813bcc21
commit fcd0342e42
15 changed files with 269 additions and 120 deletions
Download patch file Download diff file Expand all files Collapse all files

40
plugin/normalize.go
View file

@ -75,13 +75,14 @@ func (h Host) Normalize() string {
// The error can be ignore here, because this function is called after the corefile
// has already been vetted.
host, _, _ := SplitHostPort(s)
host, _, _, _ := SplitHostPort(s)
return Name(host).Normalize()
}
// SplitHostPort splits s up in a host and port portion, taking reverse address notation into account.
// String the string s should *not* be prefixed with any protocols, i.e. dns://
func SplitHostPort(s string) (host, port string, err error) {
// String the string s should *not* be prefixed with any protocols, i.e. dns://. The returned ipnet is the
// *net.IPNet that is used when the zone is a reverse and a netmask is given.
func SplitHostPort(s string) (host, port string, ipnet *net.IPNet, err error) {
// If there is: :[0-9]+ on the end we assume this is the port. This works for (ascii) domain
// names and our reverse syntax, which always needs a /mask *before* the port.
// So from the back, find first colon, and then check if its a number.
@ -89,7 +90,7 @@ func SplitHostPort(s string) (host, port string, err error) {
colon := strings.LastIndex(s, ":")
if colon == len(s)-1 {
return "", "", fmt.Errorf("expecting data after last colon: %q", s)
return "", "", nil, fmt.Errorf("expecting data after last colon: %q", s)
}
if colon != -1 {
if p, err := strconv.Atoi(s[colon+1:]); err == nil {
@ -100,33 +101,34 @@ func SplitHostPort(s string) (host, port string, err error) {
// TODO(miek): this should take escaping into account.
if len(host) > 255 {
return "", "", fmt.Errorf("specified zone is too long: %d > 255", len(host))
return "", "", nil, fmt.Errorf("specified zone is too long: %d > 255", len(host))
}
_, d := dns.IsDomainName(host)
if !d {
return "", "", fmt.Errorf("zone is not a valid domain name: %s", host)
return "", "", nil, fmt.Errorf("zone is not a valid domain name: %s", host)
}
// Check if it parses as a reverse zone, if so we use that. Must be fully
// specified IP and mask and mask % 8 = 0.
ip, net, err := net.ParseCIDR(host)
// Check if it parses as a reverse zone, if so we use that. Must be fully specified IP and mask.
ip, n, err := net.ParseCIDR(host)
ones, bits := 0, 0
if err == nil {
if rev, e := dns.ReverseAddr(ip.String()); e == nil {
ones, bits := net.Mask.Size()
if (bits-ones)%8 == 0 {
offset, end := 0, false
for i := 0; i < (bits-ones)/8; i++ {
offset, end = dns.NextLabel(rev, offset)
if end {
break
}
ones, bits = n.Mask.Size()
// Get the first lower octet boundary to see what encompassing zone we should be authoritative for.
mod := (bits - ones) % 8
nearest := (bits - ones) + mod
offset, end := 0, false
for i := 0; i < nearest/8; i++ {
offset, end = dns.NextLabel(rev, offset)
if end {
break
}
host = rev[offset:]
}
host = rev[offset:]
}
}
return host, port, nil
return host, port, n, nil
}
// Duplicated from core/dnsserver/address.go !