Initial commit

.github/dependabot.yml

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+version: 2
+updates:
+  # Maintain dependencies for GitHub Actions
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
+    assignees:
+      - "louisroyer"
+  - package-ecosystem: "gomod"
+    directory: "/"
+    schedule:
+      interval: "daily"
+    assignees:
+      - "louisroyer"

.github/workflows/create-release.yml

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+name: Release
+on:
+  push:
+    tags:
+      - "v[0-9]+.[0-9]+.[0-9]+"
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Get version number
+        id: version
+        run: echo "version=$(echo ${{ github.ref_name }} | cut -c2- -)" >> $GITHUB_OUTPUT
+      - name: Release
+        uses: ncipollo/release-action@v1
+        with:
+          generateReleaseNotes: true
+          makeLatest: "legacy"
+          name: "Version ${{ steps.version.outputs.version }}"

.github/workflows/main.yml

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+# This is a basic workflow to help you get started with Actions
+
+name: CI 
+
+# Controls when the workflow will run
+on:
+  # Triggers the workflow on push or pull request events but only for the "master" branch
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+jobs:
+    go_build:
+      runs-on: ubuntu-latest
+      steps:
+        - name: Checkout
+          uses: actions/checkout@v4
+        - name: Setup Go
+          uses: actions/setup-go@v5
+        - name: Install depends
+          run: go get .
+        - name: Build
+          run: go build -v ./...
+        - name: Vet
+          run: go vet ./...

.pre-commit-config.yaml

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+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.6.0
+    hooks:
+      - id: end-of-file-fixer
+      - id: trailing-whitespace
+      - id: mixed-line-ending
+exclude: ^.github/.*$

LICENSE

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+MIT License
+
+Copyright © 2023 Louis Royer
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# RFC 9433
+This package provides functions to implement RFC 9433 (Segment Routing over IPv6 for the Mobile User Plane).
+
+## Licence
+MIT

doc.go

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+// Copyright 2023 Louis Royer and the NextMN contributors. All rights reserved.
+// Use of this source code is governed by a MIT-style license that can be
+// found in the LICENSE file.
+// SPDX-License-Identifier: MIT
+
+// Package rfc9433 provides functions to implement RFC9433 (Segment Routing over IPv6 for the Mobile User Plane).
+package rfc9433

encoding/args-mob-session.go

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+// Copyright 2023 Louis Royer and the NextMN contributors. All rights reserved.
+// Use of this source code is governed by a MIT-style license that can be
+// found in the LICENSE file.
+// SPDX-License-Identifier: MIT
+
+package rfc9433
+
+import "encoding/binary"
+import "github.com/nextmn/rfc9433/encoding/errors"
+
+const (
+	// Field TEID
+	teidSizeByte = 4                // size of the field in bytes
+	teidSizeBit  = teidSizeByte * 8 // size of the field in bits
+	teidPosByte  = 1                // position of the field from the left in bytes
+
+	// Field QFI
+	qfiSizeBit = 6                          // size of the field
+	qfiPosBit  = 2                          // position from right of the byte in bits
+	qfiPosByte = 0                          // position from left in bytes
+	qfiMask    = (0xFF >> (8 - qfiSizeBit)) // mask (decoding: after shift to right; encoding before shift to left)
+
+	// Field R
+	rSizeBit = 1                        // size of the field
+	rPosBit  = 1                        // position from right of the byte in bits
+	rPosByte = 0                        // position from left in bytes
+	rMask    = (0xFF >> (8 - rSizeBit)) // mask (decoding: after shift to right; encoding before shift to left)
+
+	// Field U
+	uSizeBit = 1                        // size of the field
+	uPosBit  = 0                        // position from right of the byte in bits
+	uPosByte = 0                        // position from left in bytes
+	uMask    = (0xFF >> (8 - uSizeBit)) // mask (decoding: after shift to right; encoding before shift to left)
+)
+
+// Args.Mob.Session as defined in RFC 9433, section 6.1:
+//
+//	 0                   1                   2                   3
+//	 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+//	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//	|   QFI     |R|U|                PDU Session ID                 |
+//	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//	|PDU Sess(cont')|
+//	+-+-+-+-+-+-+-+-+
+//	Figure 8: Args.Mob.Session Format
+type ArgsMobSession struct {
+	qfi          uint8  // QoS Flow Identifier (6 bits)
+	r            uint8  // Reflective QoS Indication (1 bit)
+	u            uint8  // Unused and for future use (1 bit)
+	pduSessionID uint32 // Identifier of PDU Session. The GTP-U equivalent is TEID (32 bits)
+}
+
+// NewArgsMobSession creates an ArgsMobSession.
+func NewArgsMobSession(qfi uint8, r bool, u bool, pduSessionID uint32) *ArgsMobSession {
+	var ruint uint8 = 0
+	if r {
+		ruint = 1
+	}
+	var uuint uint8 = 0
+	if u {
+		uuint = 1
+	}
+	return &ArgsMobSession{
+		qfi:          qfi,
+		r:            ruint,
+		u:            uuint,
+		pduSessionID: pduSessionID,
+	}
+}
+
+// ParseArgsMobSession parses given byte sequence as an ArgsMobSession.
+func ParseArgsMobSession(b []byte) (*ArgsMobSession, error) {
+	a := &ArgsMobSession{}
+	if err := a.UnmarshalBinary(b); err != nil {
+		return nil, err
+	}
+	return a, nil
+}
+
+// QFI returns the Qos Flow Identifier for this ArgsMobSession.
+func (a *ArgsMobSession) QFI() uint8 {
+	return a.qfi
+}
+
+// R returns the Reflective QoS Indication for this ArgsMobSession.
+func (a *ArgsMobSession) R() bool {
+	if a.r == 0 {
+		return false
+	}
+	return true
+}
+
+// U returns the U bit for this ArgsMobSession.
+func (a *ArgsMobSession) U() bool {
+	if a.u == 0 {
+		return false
+	}
+	return true
+}
+
+// PDUSessionID returns the PDU Session Identifier for this ArgsMobSession. The GTP-U equivalent is TEID.
+func (a *ArgsMobSession) PDUSessionID() uint32 {
+	return a.pduSessionID
+}
+
+// MarshalLen returns the serial length of ArgsMobSession.
+func (a *ArgsMobSession) MarshalLen() int {
+	return 5
+}
+
+// Marshal returns the byte sequence generated from ArgsMobSession.
+func (a *ArgsMobSession) Marshal() ([]byte, error) {
+	b := make([]byte, a.MarshalLen())
+	if err := a.MarshalTo(b); err != nil {
+		return nil, err
+	}
+	return b, nil
+}
+
+// MarshalTo puts the byte sequence in the byte array given as b.
+func (a *ArgsMobSession) MarshalTo(b []byte) error {
+	if len(b) < a.MarshalLen() {
+		return errors.ErrTooShortToMarshal
+	}
+	b[qfiPosByte] |= (qfiMask & a.qfi) << qfiPosBit
+	b[rPosByte] |= (rMask & a.r) << rPosBit
+	b[uPosByte] |= (uMask & a.u) << uPosBit
+	binary.BigEndian.PutUint32(b[teidPosByte:teidPosByte+teidSizeByte], a.pduSessionID)
+	return nil
+}
+
+// UnmarshalBinary sets the values retrieved from byte sequence in an ArgsMobSession.
+func (a *ArgsMobSession) UnmarshalBinary(b []byte) error {
+	if len(b) < 5 {
+		return errors.ErrTooShortToParse
+	}
+	a.qfi = qfiMask & (b[qfiPosByte] >> qfiPosBit)
+	a.r = rMask & (b[rPosByte] >> rPosBit)
+	a.u = uMask & (b[uPosByte] >> uPosBit)
+	a.pduSessionID = binary.BigEndian.Uint32(b[teidPosByte : teidPosByte+teidSizeByte])
+	return nil
+}

encoding/doc.go

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+// Copyright 2023 Louis Royer and the NextMN contributors. All rights reserved.
+// Use of this source code is governed by a MIT-style license that can be
+// found in the LICENSE file.
+// SPDX-License-Identifier: MIT
+
+// Package encoding provides encoding and decoding of IPv6 Addresses
+// used by RFC 9433 (Segment Routing over IPv6 for the Mobile User Plane).
+package rfc9433

encoding/errors/doc.go

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+// Copyright 2023 Louis Royer and the NextMN contributors. All rights reserved.
+// Use of this source code is governed by a MIT-style license that can be
+// found in the LICENSE file.
+// SPDX-License-Identifier: MIT
+
+// Package errors provides common encoding errors used by rfc9433 package.
+package errors

encoding/errors/errors.go

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+// Copyright 2023 Louis Royer and the NextMN contributors. All rights reserved.
+// Use of this source code is governed by a MIT-style license that can be
+// found in the LICENSE file.
+// SPDX-License-Identifier: MIT
+
+package errors
+
+import "errors"
+
+var (
+	ErrTooShortToMarshal = errors.New("too short to serialize")
+	ErrTooShortToParse   = errors.New("too short to parse")
+	ErrPrefixLength      = errors.New("wrong prefix length")
+	ErrOutOfRange        = errors.New("out of range")
+)