Implement monorepo layout
Implemented the nexantic monorepo.
Smalltown code was moved to `core`. From now on all code will live in top level directories named after the projects with the exception for general purpose libraries which should go to `<lang>libs`.
General build and utility folders are underscore prefixed.
The repo name will from now on be rNXT (nexantic). I think this change makes sense since components in this repo will not all be part of Smalltown, the Smalltown brand has been claimed by Signon GmbH so we need to change it anyway and the longer we wait the harder it will be to change/move it.
Test Plan: Launched Smalltown using `./scripts/bin/bazel run //core/scripts:launch`
X-Origin-Diff: phab/D210
GitOrigin-RevId: fa5a7f08143d2ead2cb7206b4c63ab641794162c
diff --git a/core/internal/network/main.go b/core/internal/network/main.go
new file mode 100644
index 0000000..ecb0d18
--- /dev/null
+++ b/core/internal/network/main.go
@@ -0,0 +1,154 @@
+// Copyright 2020 The Monogon Project Authors.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+// 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 network
+
+import (
+ "context"
+ "fmt"
+ "git.monogon.dev/source/nexantic.git/core/internal/common"
+ "net"
+ "os"
+
+ "github.com/insomniacslk/dhcp/dhcpv4/nclient4"
+ "github.com/vishvananda/netlink"
+ "go.uber.org/zap"
+ "golang.org/x/sys/unix"
+)
+
+const (
+ resolvConfPath = "/etc/resolv.conf"
+ resolvConfSwapPath = "/etc/resolv.conf.new"
+)
+
+type Service struct {
+ *common.BaseService
+ config Config
+ dhcp4Client *nclient4.Client
+}
+
+type Config struct {
+}
+
+func NewNetworkService(config Config, logger *zap.Logger) (*Service, error) {
+ s := &Service{
+ config: config,
+ }
+ s.BaseService = common.NewBaseService("network", logger, s)
+ return s, nil
+}
+
+func setResolvconf(nameservers []net.IP, searchDomains []string) error {
+ os.Mkdir("/etc", 0755) // Error intentionally not checked
+ newResolvConf, err := os.Create(resolvConfSwapPath)
+ if err != nil {
+ return err
+ }
+ defer newResolvConf.Close()
+ defer os.Remove(resolvConfSwapPath)
+ for _, ns := range nameservers {
+ if _, err := newResolvConf.WriteString(fmt.Sprintf("nameserver %v\n", ns)); err != nil {
+ return err
+ }
+ }
+ for _, searchDomain := range searchDomains {
+ if _, err := newResolvConf.WriteString(fmt.Sprintf("search %v", searchDomain)); err != nil {
+ return err
+ }
+ }
+ newResolvConf.Close()
+ // Atomically swap in new config
+ return unix.Rename(resolvConfSwapPath, resolvConfPath)
+}
+
+func addNetworkRoutes(link netlink.Link, addr net.IPNet, gw net.IP) error {
+ if err := netlink.AddrReplace(link, &netlink.Addr{IPNet: &addr}); err != nil {
+ return err
+ }
+ if err := netlink.RouteAdd(&netlink.Route{
+ Dst: &net.IPNet{IP: net.IPv4(0, 0, 0, 0), Mask: net.IPv4Mask(0, 0, 0, 0)},
+ Gw: gw,
+
+ Scope: netlink.SCOPE_UNIVERSE,
+ }); err != nil {
+ return fmt.Errorf("Failed to add default route: %w", err)
+ }
+ return nil
+}
+
+const (
+ stateInitialize = 1
+ stateSelect = 2
+ stateBound = 3
+ stateRenew = 4
+ stateRebind = 5
+)
+
+var dhcpBroadcastAddr = &net.UDPAddr{IP: net.IP{255, 255, 255, 255}, Port: 67}
+
+// TODO(lorenz): This is a super terrible DHCP client, but it works for QEMU slirp
+func (s *Service) dhcpClient(iface netlink.Link) error {
+ client, err := nclient4.New(iface.Attrs().Name)
+ if err != nil {
+ panic(err)
+ }
+ _, ack, err := client.Request(context.Background())
+ if err != nil {
+ panic(err)
+ }
+ s.Logger.Info("Network service got IP", zap.String("ip", ack.YourIPAddr.String()))
+ if err := setResolvconf(ack.DNS(), []string{}); err != nil {
+ s.Logger.Warn("Failed to set resolvconf", zap.Error(err))
+ }
+ if err := addNetworkRoutes(iface, net.IPNet{IP: ack.YourIPAddr, Mask: ack.SubnetMask()}, ack.GatewayIPAddr); err != nil {
+ s.Logger.Warn("Failed to add routes", zap.Error(err))
+ }
+ return nil
+}
+
+func (s *Service) OnStart() error {
+ s.Logger.Info("Starting network service")
+ links, err := netlink.LinkList()
+ if err != nil {
+ s.Logger.Fatal("Failed to list network links", zap.Error(err))
+ }
+ var ethernetLinks []netlink.Link
+ for _, link := range links {
+ attrs := link.Attrs()
+ if link.Type() == "device" && len(attrs.HardwareAddr) > 0 {
+ if len(attrs.HardwareAddr) == 6 { // Ethernet
+ if attrs.Flags&net.FlagUp != net.FlagUp {
+ netlink.LinkSetUp(link) // Attempt to take up all ethernet links
+ }
+ ethernetLinks = append(ethernetLinks, link)
+ } else {
+ s.Logger.Info("Ignoring non-Ethernet interface", zap.String("interface", attrs.Name))
+ }
+ }
+ }
+ if len(ethernetLinks) == 1 {
+ link := ethernetLinks[0]
+ go s.dhcpClient(link)
+
+ } else {
+ s.Logger.Warn("Network service cannot yet handle more than one interface :(")
+ }
+ return nil
+}
+
+func (s *Service) OnStop() error {
+ return nil
+}