From 70e7acdb23715298624d123f7cc7c9dbcdf0465c Mon Sep 17 00:00:00 2001
From: Paul Holzinger <paul.holzinger@web.de>
Date: Mon, 23 Nov 2020 11:41:40 +0100
Subject: Fix ip-range for classless subnet masks
The `LastIPInSubnet` function worked only for classful subnet
masks (e.g. /8, /16, /24). For non standard subnet masks this
returned the wrong ip address.
This works now for all subnet mask. A unit test is added to
ensure this.
Signed-off-by: Paul Holzinger <paul.holzinger@web.de>
---
libpod/network/subnet.go | 14 +++++-----
libpod/network/subnet_test.go | 62 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 69 insertions(+), 7 deletions(-)
(limited to 'libpod/network')
diff --git a/libpod/network/subnet.go b/libpod/network/subnet.go
index 90f0cdfce..120038e57 100644
--- a/libpod/network/subnet.go
+++ b/libpod/network/subnet.go
@@ -54,14 +54,10 @@ func LastIPInSubnet(addr *net.IPNet) (net.IP, error) { //nolint:interfacer
ones, bits := cidr.Mask.Size()
if ones == bits {
- return FirstIPInSubnet(cidr)
+ return cidr.IP, nil
}
- hostStart := ones / 8
- // Handle the first host byte
- cidr.IP[hostStart] |= 0xff & cidr.Mask[hostStart]
- // Fill the rest with ones
- for i := hostStart; i < len(cidr.IP); i++ {
- cidr.IP[i] = 0xff
+ for i := range cidr.IP {
+ cidr.IP[i] = cidr.IP[i] | ^cidr.Mask[i]
}
return cidr.IP, nil
}
@@ -73,6 +69,10 @@ func FirstIPInSubnet(addr *net.IPNet) (net.IP, error) { //nolint:interfacer
if err != nil {
return nil, err
}
+ ones, bits := cidr.Mask.Size()
+ if ones == bits {
+ return cidr.IP, nil
+ }
cidr.IP[len(cidr.IP)-1]++
return cidr.IP, nil
}
diff --git a/libpod/network/subnet_test.go b/libpod/network/subnet_test.go
index 917c3be88..55b2443bd 100644
--- a/libpod/network/subnet_test.go
+++ b/libpod/network/subnet_test.go
@@ -33,3 +33,65 @@ func TestNextSubnet(t *testing.T) {
})
}
}
+
+func TestFirstIPInSubnet(t *testing.T) {
+ tests := []struct {
+ name string
+ args *net.IPNet
+ want net.IP
+ wantErr bool
+ }{
+ {"class b", parseCIDR("192.168.0.0/16"), net.ParseIP("192.168.0.1"), false},
+ {"class c", parseCIDR("192.168.1.0/24"), net.ParseIP("192.168.1.1"), false},
+ {"cidr /23", parseCIDR("192.168.0.0/23"), net.ParseIP("192.168.0.1"), false},
+ {"cidr /25", parseCIDR("192.168.1.0/25"), net.ParseIP("192.168.1.1"), false},
+ {"cidr /26", parseCIDR("172.16.1.128/26"), net.ParseIP("172.16.1.129"), false},
+ {"class a", parseCIDR("10.0.0.0/8"), net.ParseIP("10.0.0.1"), false},
+ {"cidr /32", parseCIDR("192.168.255.4/32"), net.ParseIP("192.168.255.4"), false},
+ {"cidr /31", parseCIDR("192.168.255.4/31"), net.ParseIP("192.168.255.5"), false},
+ }
+ for _, tt := range tests {
+ test := tt
+ t.Run(test.name, func(t *testing.T) {
+ got, err := FirstIPInSubnet(test.args)
+ if (err != nil) != test.wantErr {
+ t.Errorf("FirstIPInSubnet() error = %v, wantErr %v", err, test.wantErr)
+ return
+ }
+ if !got.Equal(test.want) {
+ t.Errorf("FirstIPInSubnet() got = %v, want %v", got, test.want)
+ }
+ })
+ }
+}
+
+func TestLastIPInSubnet(t *testing.T) {
+ tests := []struct {
+ name string
+ args *net.IPNet
+ want net.IP
+ wantErr bool
+ }{
+ {"class b", parseCIDR("192.168.0.0/16"), net.ParseIP("192.168.255.255"), false},
+ {"class c", parseCIDR("192.168.1.0/24"), net.ParseIP("192.168.1.255"), false},
+ {"cidr /23", parseCIDR("192.168.0.0/23"), net.ParseIP("192.168.1.255"), false},
+ {"cidr /25", parseCIDR("192.168.1.0/25"), net.ParseIP("192.168.1.127"), false},
+ {"cidr /26", parseCIDR("172.16.1.128/26"), net.ParseIP("172.16.1.191"), false},
+ {"class a", parseCIDR("10.0.0.0/8"), net.ParseIP("10.255.255.255"), false},
+ {"cidr /32", parseCIDR("192.168.255.4/32"), net.ParseIP("192.168.255.4"), false},
+ {"cidr /31", parseCIDR("192.168.255.4/31"), net.ParseIP("192.168.255.5"), false},
+ }
+ for _, tt := range tests {
+ test := tt
+ t.Run(test.name, func(t *testing.T) {
+ got, err := LastIPInSubnet(test.args)
+ if (err != nil) != test.wantErr {
+ t.Errorf("LastIPInSubnet() error = %v, wantErr %v", err, test.wantErr)
+ return
+ }
+ if !got.Equal(test.want) {
+ t.Errorf("LastIPInSubnet() got = %v, want %v", got, test.want)
+ }
+ })
+ }
+}
--
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