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fix: reamap mask
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@cheina97
cheina97 committed Feb 10, 2025
1 parent 4b070bb commit 7c0afe1
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Showing 4 changed files with 239 additions and 18 deletions.
3 changes: 1 addition & 2 deletions pkg/liqoctl/test/network/check/ip.go
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Original file line number Diff line number Diff line change
Expand Up @@ -127,8 +127,7 @@ func forgeIPTarget(ctx context.Context, cl clientctrl.Client, localIPRemapped ma
if !needsRemap {
target = append(target, ipnet.String())
} else {
maskLen, _ := cidrtarget.Mask.Size()
mapping.RemapMask(ipnet, *cidrtarget, maskLen)
ipnet = mapping.RemapMask(ipnet, *cidrtarget)
target = append(target, ipnet.String())
}
}
Expand Down
90 changes: 74 additions & 16 deletions pkg/utils/ipam/mapping/ips.go
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ package mapping

import (
"context"
"encoding/binary"
"fmt"
"net"

Expand Down Expand Up @@ -134,7 +135,6 @@ func MapAddress(ctx context.Context, cl client.Client,
func MapAddressWithConfiguration(cfg *networkingv1beta1.Configuration, address string) (string, error) {
var (
podnet, podnetMapped, extnet, extnetMapped *net.IPNet
podNetMaskLen, extNetMaskLen int
err error
)

Expand All @@ -150,7 +150,6 @@ func MapAddressWithConfiguration(cfg *networkingv1beta1.Configuration, address s
if err != nil {
return "", err
}
podNetMaskLen, _ = podnetMapped.Mask.Size()
}

_, extnet, err = net.ParseCIDR(cidrutils.GetPrimary(cfg.Spec.Remote.CIDR.External).String())
Expand All @@ -162,29 +161,88 @@ func MapAddressWithConfiguration(cfg *networkingv1beta1.Configuration, address s
if err != nil {
return "", err
}
extNetMaskLen, _ = extnetMapped.Mask.Size()
}

paddr := net.ParseIP(address)
if podNeedsRemap && podnet.Contains(paddr) {
return RemapMask(paddr, *podnetMapped, podNetMaskLen).String(), nil
return RemapMask(paddr, *podnetMapped).String(), nil
}
if extNeedsRemap && extnet.Contains(paddr) {
return RemapMask(paddr, *extnetMapped, extNetMaskLen).String(), nil
return RemapMask(paddr, *extnetMapped).String(), nil
}

return address, nil
}

// RemapMask remaps the mask of the address.
// Consider that net.IP is always a slice of 16 bytes (big-endian).
// The mask is a slice of 4 or 16 bytes (big-endian).
func RemapMask(addr net.IP, mask net.IPNet, maskLen int) net.IP {
maskLenBytes := maskLen / 8
for i := 0; i < maskLenBytes; i++ {
// i+(len(addr)-len(mask.IP)) allows to start from the rightmost byte of the address.
// e.g if addr is ipv4 len(addr) = 16, and mask is ipv4 len(mask.IP) = 4, then we start from addr[12].
addr[i+(len(addr)-len(mask.IP))] = mask.IP[i]
}
return addr
// RemapMask take an IP address and a network mask and remap the address to the network.
// This means that the host part of the address is preserved, while the network part is replaced with the one in the mask.
//
// Example:
// addr: 10.1.0.1
// mask: 40.32.0.0/10
// result: 40.1.0.1
// addrBin: 00001010000000010000000000000001
// maskBin: 11111111110000000000000000000000
// netBin : 00101000000000000000000000000000
// hostBin: 00000000000000010000000000000001
// resultBin : 00101000000000010000000000000001
//
// addr: 10.255.1.1
// mask: 78.5.78.143/18
// result: 78.5.65.1
// addrBin: 00001010111111110000000100000001
// maskBin: 11111111111111111100000000000000
// netBin : 01001110000001010100000000000000
// hostBin: 00000000000000000000000100000001
// resultBin: 01001110000001010100000100000001 // nolint: godot // this comment must not end with a period.
func RemapMask(addr net.IP, mask net.IPNet) net.IP {
switch len(mask.IP) {
case net.IPv4len:
addr = addr.To4()

// Convert addr,mask,net to binary representation
// Check the comment of the RemapMask function to better understand the values stored in the variables.
addrBin := binary.BigEndian.Uint32(addr)
maskBin := binary.BigEndian.Uint32(mask.Mask)
netBin := binary.BigEndian.Uint32(mask.IP)

// Calculate the host part of the address
// We need to invert the mask and apply the AND operation to the address
// to keep only the host part
hostBin := addrBin & (^maskBin)

// Calculate the result
// We need to apply the OR operation to the network part and the host part
result := netBin | hostBin

resultBytes := make([]byte, 4)

binary.BigEndian.PutUint32(resultBytes, result)

return resultBytes
case net.IPv6len:
// Refer to the IPv4 case for the explanation of the following operations.
addr = addr.To16()

addrBin1 := binary.BigEndian.Uint64(addr[:8])
addrBin2 := binary.BigEndian.Uint64(addr[8:])
maskBin1 := binary.BigEndian.Uint64(mask.Mask[:8])
maskBin2 := binary.BigEndian.Uint64(mask.Mask[8:])
netBin1 := binary.BigEndian.Uint64(mask.IP[:8])
netBin2 := binary.BigEndian.Uint64(mask.IP[8:])

hostBin1 := addrBin1 & (^maskBin1)
hostBin2 := addrBin2 & (^maskBin2)

result1 := netBin1 | hostBin1
result2 := netBin2 | hostBin2

resultBytes := make([]byte, 16)

binary.BigEndian.PutUint64(resultBytes[:8], result1)
binary.BigEndian.PutUint64(resultBytes[8:], result2)

return resultBytes
}
return nil
}
27 changes: 27 additions & 0 deletions pkg/utils/ipam/mapping/ips_suite_test.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,27 @@
// Copyright 2019-2025 The Liqo Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package mapping

import (
"testing"

. "github.com/onsi/ginkgo/v2"
. "github.com/onsi/gomega"
)

func TestMapping(t *testing.T) {
RegisterFailHandler(Fail)
RunSpecs(t, "Mapping Suite")
}
137 changes: 137 additions & 0 deletions pkg/utils/ipam/mapping/ips_test.go
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,137 @@
// Copyright 2019-2025 The Liqo Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package mapping

import (
"fmt"
"net"

. "github.com/onsi/ginkgo/v2"
. "github.com/onsi/gomega"
)

var _ = Describe("RemapMask", func() {
DescribeTable("IPv4 remapping",
func(ipStr, cidrStr string, expectedStr string) {
addr := net.ParseIP(ipStr)
Expect(addr).NotTo(BeNil())

_, mask, err := net.ParseCIDR(cidrStr)
Expect(err).NotTo(HaveOccurred()) // Check no error occurs
Expect(mask).NotTo(BeNil())

expected := net.ParseIP(expectedStr).To4()
Expect(expected).NotTo(BeNil())

result := RemapMask(addr, *mask)
Expect(result).To(Equal(expected))
},
Entry("IPv4 remapping", "192.168.1.20", "10.0.0.0/27", "10.0.0.20"),
Entry("IPv4 remapping", "192.168.2.20", "10.0.0.0/27", "10.0.0.20"),
Entry("IPv4 remapping", "192.168.1.50", "10.0.0.0/27", "10.0.0.18"),
Entry("IPv4 remapping", "192.168.2.50", "10.0.0.0/27", "10.0.0.18"),
Entry("IPv4 remapping", "192.168.1.1", "255.255.255.128/25", "255.255.255.129"),
Entry("IPv4 remapping", "172.16.0.1", "255.255.255.128/25", "255.255.255.129"),
Entry("IPv4 remapping", "192.168.1.200", "255.255.255.128/25", "255.255.255.200"),
Entry("IPv4 remapping", "192.168.1.10", "255.255.255.0/24", "255.255.255.10"),
Entry("IPv4 remapping", "192.168.1.100", "255.255.255.0/24", "255.255.255.100"),
Entry("IPv4 remapping", "172.16.0.1", "255.255.240.0/20", "255.255.240.1"),
Entry("IPv4 remapping", "172.16.1.1", "255.255.240.0/20", "255.255.241.1"),
Entry("IPv4 remapping", "192.168.1.10", "255.4.224.0/19", "255.4.225.10"),
Entry("IPv4 remapping", "192.168.2.10", "255.4.224.0/19", "255.4.226.10"),
Entry("IPv4 remapping", "10.0.0.1", "255.255.192.0/18", "255.255.192.1"),
Entry("IPv4 remapping", "10.255.1.1", "78.5.78.143/18", "78.5.65.1"),
Entry("IPv4 remapping", "192.168.1.20", "192.168.0.0/16", "192.168.1.20"),
Entry("IPv4 remapping", "192.168.2.20", "192.168.0.0/16", "192.168.2.20"),
Entry("IPv4 remapping", "172.16.1.1", "172.16.0.0/12", "172.16.1.1"),
Entry("IPv4 remapping", "172.16.2.1", "172.16.0.0/12", "172.16.2.1"),
Entry("IPv4 remapping", "10.0.0.1", "255.192.0.0/10", "255.192.0.1"),
Entry("IPv4 remapping", "10.1.0.1", "40.32.0.0/10", "40.1.0.1"),
Entry("IPv4 remapping", "10.0.0.1", "255.0.0.0/8", "255.0.0.1"),
Entry("IPv4 remapping", "10.0.0.50", "255.0.0.0/8", "255.0.0.50"),
Entry("IPv4 remapping", "10.1.1.1", "20.0.0.0/8", "20.1.1.1"),
Entry("IPv4 remapping", "10.2.1.1", "20.0.0.0/8", "20.2.1.1"),
Entry("IPv4 remapping", "192.168.1.10", "240.0.0.0/4", "240.168.1.10"),
Entry("IPv4 remapping", "192.168.2.10", "240.0.0.0/4", "240.168.2.10"),
Entry("IPv4 remapping", "192.168.1.100", "0.0.0.0/0", "192.168.1.100"),
Entry("IPv4 remapping", "10.0.0.1", "255.255.255.255/32", "255.255.255.255"),
Entry("IPv4 remapping", "172.16.1.0", "172.16.0.0/16", "172.16.1.0"),
Entry("IPv4 remapping", "172.16.1.255", "172.16.0.0/16", "172.16.1.255"),
Entry("IPv4 remapping", "10.10.10.10", "192.168.1.0/24", "192.168.1.10"),
Entry("IPv4 remapping", "192.168.1.255", "10.0.0.0/8", "10.168.1.255"),
Entry("IPv4 remapping", "224.0.0.1", "192.168.1.0/24", "192.168.1.1"),
Entry("IPv4 remapping", "127.0.0.1", "10.0.0.0/8", "10.0.0.1"),
Entry("IPv4 remapping", "192.168.1.1", "10.0.0.0/30", "10.0.0.1"),
Entry("IPv4 remapping", "192.168.1.2", "10.0.0.0/30", "10.0.0.2"),
Entry("IPv4 remapping", "192.168.1.10", "10.0.0.0/29", "10.0.0.2"),
Entry("IPv4 remapping", "172.16.5.10", "192.168.0.0/21", "192.168.5.10"),
Entry("IPv4 remapping", "10.0.5.20", "172.16.0.0/13", "172.16.5.20"),
Entry("IPv4 remapping", "192.168.1.100", "10.0.0.0/27", "10.0.0.4"),
Entry("IPv4 remapping", "172.20.100.5", "192.168.0.0/17", "192.168.100.5"),
Entry("IPv4 remapping", "192.168.3.50", "10.0.0.0/23", "10.0.1.50"),
Entry("IPv4 remapping", "10.1.1.2", "192.168.1.0/30", "192.168.1.2"),
Entry("IPv4 remapping", "192.168.5.33", "172.16.1.0/26", "172.16.1.33"),
)

DescribeTable("IPv6 address remapping",
func(ipStr, cidrStr string, expectedStr string) {
addr := net.ParseIP(ipStr)
Expect(addr).NotTo(BeNil())

_, mask, err := net.ParseCIDR(cidrStr)
Expect(err).NotTo(HaveOccurred())
Expect(mask).NotTo(BeNil())

expected := net.ParseIP(expectedStr).To16()
Expect(expected).NotTo(BeNil())

result := RemapMask(addr, *mask)

fmt.Printf("expected: %s\n", expected)
fmt.Printf("result: %s\n", result)

Expect(result).To(Equal(expected))
},
Entry("IPv6 remapping", "2001:db8::1", "2001:db8::/32", "2001:db8::1"),
Entry("IPv6 remapping", "2001:db8:1::1", "2001:db8::/32", "2001:db8:1::1"),
Entry("IPv6 remapping", "2001:db8::1", "2001:db8:1::/48", "2001:db8:1::1"),
Entry("IPv6 remapping", "2001:db8:2::1", "2001:db8:1::/48", "2001:db8:1::1"),
Entry("IPv6 remapping", "2001:db8::1", "2001:db8:1:2::/64", "2001:db8:1:2::1"),
Entry("IPv6 remapping", "2001:db8:1::1", "2001:db8:1:2::/64", "2001:db8:1:2::1"),
Entry("IPv6 remapping", "2001:db8::1", "2001:db8:1:2:3::/80", "2001:db8:1:2:3::1"),
Entry("IPv6 remapping", "2001:db8:1::1", "2001:db8:1:2:3::/80", "2001:db8:1:2:3::1"),
Entry("IPv6 remapping", "2001:db8::1", "2001:db8:1:2:3:4::/96", "2001:db8:1:2:3:4::1"),
Entry("IPv6 remapping", "2001:db8:1::1", "2001:db8:1:2:3:4::/96", "2001:db8:1:2:3:4::1"),
Entry("IPv6 remapping", "2001:db8::1", "2001:db8:1:2:3:4:5::/112", "2001:db8:1:2:3:4:5:1"),
Entry("IPv6 remapping", "2001:db8:1::1", "2001:db8:1:2:3:4:5::/112", "2001:db8:1:2:3:4:5:1"),
Entry("IPv6 remapping", "2001:db8:1::1", "2001:db8:1:2:3:4:5:6/128", "2001:db8:1:2:3:4:5:6"),
Entry("IPv6 remapping", "2001:db8::1", "2001:db8::/16", "2001:db8::1"),
Entry("IPv6 remapping", "2001:db8:abcd::1", "2001:db8::/56", "2001:db8::1"),
Entry("IPv6 remapping", "2001:db8:abcd:1234::1", "2001:db8::/64", "2001:db8::1"),
Entry("IPv6 remapping", "fc00::1", "fd00::/8", "fd00::1"),
Entry("IPv6 remapping", "fd00:1234::1", "fc00::/7", "fd00:1234::1"),
Entry("IPv6 remapping", "fe80::1", "fd00::/8", "fd80::1"),
Entry("IPv6 remapping", "2001:db8:abcd::1", "2001:db8:1234::/32", "2001:db8:abcd::1"),
Entry("IPv6 remapping", "2001::1", "2002::/16", "2002::1"),
Entry("IPv6 remapping", "2001:db8:abcd::1", "2001:db8::/49", "2001:db8::1"),
Entry("IPv6 remapping", "2001:db8:abcd:1234::1", "2001:db8::/57", "2001:db8:0:34::1"),
Entry("IPv6 remapping", "2001:db8:abcd:1234::1", "2001:db8::/69", "2001:db8::1"),
Entry("IPv6 remapping", "2001:db8:abcd:1234::1", "2001:db8::/73", "2001:db8::1"),
Entry("IPv6 remapping", "2001:db8::1", "2001:db8::/127", "2001:db8::1"),
Entry("IPv6 remapping", "2001:db8:abcd::1", "2001:db8::/37", "2001:db8:3cd::1"),
Entry("IPv6 remapping", "2001:fdb8:abcd::45a3:1", "2001:d2f::/53", "2001:d2f::45a3:1"),
Entry("IPv6 remapping", "2001:db8:abcd:1234::1", "2001:db8::/61", "2001:db8:0:4::1"),
)
})

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