package main
import (
- "bufio"
- "encoding/json"
- "fmt"
"log"
"os"
- "os/exec"
- "path/filepath"
- "strconv"
- "strings"
- "syscall"
)
func main() {
}
}
- for _, node := range cfg.Nodes {
- log.Printf("Setting up node %q ...", node.Name)
-
- // One namespace per node, named as the node's name
- ns := node.Name
- if netnsExists(ns) {
- // Terminate processes in old namespaces
- for _, x := range netnsPids(ns) {
- log.Printf(" Killing old PID %d", x)
- err := syscall.Kill(x, syscall.SIGTERM)
- if err != nil {
- log.Fatalf("failed to kill %d: %v", x, err)
- }
- // Also try SIGHUP to terminate shells which ignore SIGTERM
- _ = syscall.Kill(x, syscall.SIGHUP)
- }
- // Prevent any conflicts with existing data
- ip("netns", "del", ns)
- // Don't remove anything in /etc/netns/ as the user might store
- // configuration there!
- }
- ip("netns", "add", ns)
-
- // Write /etc/netns/$netns/hosts with all known hosts
- nsCfgPath := filepath.Join("/etc/netns", ns)
- nsHostsPath := filepath.Join(nsCfgPath, "hosts")
- log.Printf(" Writing %q", nsHostsPath)
- err := os.MkdirAll(nsCfgPath, 0755)
- if err != nil {
- log.Fatal(err)
- }
- err = writeHosts(cfg, nsHostsPath)
- if err != nil {
- log.Fatal(err)
- }
-
- // Enable IPv4 and IPv6 forwarding
- ip("netns", "exec", ns, "sysctl", "-q", "net.ipv4.ip_forward=1")
- ip("netns", "exec", ns, "sysctl", "-q", "net.ipv6.conf.all.forwarding=1")
-
- ip("-n", ns, "link", "set", "lo", "up")
- // Extra interface for our loopback addresses; keeping them separate
- // can make things easier (e.g. using the interface for protocols).
- lo := "lo2"
- ip("-n", ns, "link", "add", lo, "type", "dummy")
- ip("-n", ns, "link", "set", lo, "up")
- for _, x := range node.Loopbacks {
- ip("-n", ns, "addr", "add", x.String(), "dev", lo)
- }
- }
-
- log.Printf("Setting up links ...")
- for _, link := range cfg.Links {
- nsa := link.A.Node.Name
- nsb := link.B.Node.Name
-
- log.Printf(" Link between %q and %q ...", nsa, nsb)
-
- // Use name of other node for the interface
- la := nsb
- lb := nsa
- // Support multiple links between nodes
- if ifaceExists(nsa, la) {
- la = nextFreeIface(nsa, la)
- }
- if ifaceExists(nsb, lb) {
- lb = nextFreeIface(nsb, lb)
- }
-
- t := "veth"
- if link.Layer3 {
- t = "netkit" // since kernel 6.7, iproute2 6.8
- }
- ip("link", "add", "tmpa", "type", t, "peer", "name", "tmpb")
- ip("link", "set", "tmpa", "netns", nsa)
- ip("link", "set", "tmpb", "netns", nsb)
- ip("-n", nsa, "link", "set", "tmpa", "name", la)
- ip("-n", nsb, "link", "set", "tmpb", "name", lb)
- for _, x := range link.A.Addrs {
- ip("-n", nsa, "addr", "add", x.String(), "dev", la)
- }
- for _, x := range link.B.Addrs {
- ip("-n", nsb, "addr", "add", x.String(), "dev", lb)
- }
- ip("-n", nsa, "link", "set", la, "up")
- ip("-n", nsb, "link", "set", lb, "up")
- }
-
- log.Printf("Starting cmds ...")
- for _, node := range cfg.Nodes {
- log.Printf(" For node %q", node.Name)
- ns := node.Name
- for _, cmd := range cfg.Cmds {
- ip("netns", "exec", ns, "sh", "-c", cmd, "argv0", ns)
- }
- }
-}
-
-func ip(args ...string) {
- xargs := append([]string{"ip"}, args...)
- log.Printf(" Running %q", xargs)
-
- cmd := exec.Command("ip", args...)
- cmd.Stdout = os.Stdout
- cmd.Stderr = os.Stderr
- err := cmd.Run()
- if err != nil {
- log.Fatalf("failed to run %q: %v", xargs, err)
- }
-}
-
-func netnsExists(name string) bool {
- _, err := os.Stat(filepath.Join("/run/netns", name))
- if err != nil {
- if os.IsNotExist(err) {
- return false
- }
- log.Fatal(err)
- }
- return true
-}
-
-func netnsPids(netns string) []int {
- args := []string{"netns", "pids", netns}
- xargs := append([]string{"ip"}, args...)
-
- cmd := exec.Command("ip", args...)
- out, err := cmd.Output()
- if err != nil {
- log.Fatalf("failed to run %q: %v", xargs, err)
- }
-
- isNewline := func(c rune) bool {
- return c == '\n'
- }
-
- var res []int
- xs := strings.FieldsFunc(string(out), isNewline)
- for _, x := range xs {
- y, err := strconv.Atoi(x)
- if err != nil {
- log.Fatalf("invalid output from %q: %q: %v", xargs, out, err)
- }
- res = append(res, y)
- }
- return res
-}
-
-func ifaceExists(netns, name string) bool {
- args := []string{"-n", netns, "-json", "link"}
- xargs := append([]string{"ip"}, args...)
-
- cmd := exec.Command("ip", args...)
- out, err := cmd.Output()
- if err != nil {
- log.Fatalf("failed to run %q: %v", xargs, err)
- }
-
- var ifaces []struct {
- Ifname string `json:"ifname"`
- }
- err = json.Unmarshal(out, &ifaces)
- if err != nil {
- log.Fatalf("failed to parse output from ip (%q): %v", out, err)
- }
-
- for _, x := range ifaces {
- if x.Ifname == name {
- return true
- }
- }
- return false
-}
-
-func nextFreeIface(netns, name string) string {
- i := 2
- x := name
- for ifaceExists(netns, x) {
- x = fmt.Sprintf("%s_%d", name, i)
- i++
- }
- return x
-}
-
-// writeHosts writes a hosts-file (i.e. /etc/hosts) with all known addresses
-// and their corresponding node names.
-func writeHosts(cfg *Config, path string) error {
- f, err := os.Create(path)
- if err != nil {
- return err
- }
- defer f.Close()
- w := bufio.NewWriter(f)
-
- // Standard entries
- fmt.Fprintf(w, "127.0.0.1 localhost\n")
- fmt.Fprintf(w, "::1 localhost ip6-localhost ip6-loopback\n")
-
- for _, node := range cfg.Nodes {
- for _, x := range node.Loopbacks {
- fmt.Fprintf(w, "%s %s-loop\n", x.String(), node.Name)
- }
- }
-
- for _, link := range cfg.Links {
- for _, x := range link.A.Addrs {
- fmt.Fprintf(w, "%s %s\n", x.Addr().String(), link.A.Node.Name)
- }
- for _, x := range link.B.Addrs {
- fmt.Fprintf(w, "%s %s\n", x.Addr().String(), link.B.Node.Name)
- }
- }
-
- err = w.Flush()
- if err != nil {
- return err
- }
- err = f.Sync()
- if err != nil {
- return err
- }
- return nil
+ mustUp(cfg)
}
// vi: set noet ts=4 sw=4 sts=4:
--- /dev/null
+// Apply configuration and setup everything.
+
+// SPDX-License-Identifier: GPL-3.0-or-later
+// Copyright (C) 2024 Simon Ruderich
+
+package main
+
+import (
+ "bufio"
+ "encoding/json"
+ "fmt"
+ "log"
+ "os"
+ "os/exec"
+ "path/filepath"
+ "strconv"
+ "strings"
+ "syscall"
+)
+
+func mustUp(cfg *Config) {
+ for _, node := range cfg.Nodes {
+ log.Printf("Setting up node %q ...", node.Name)
+
+ // One namespace per node, named as the node's name
+ ns := node.Name
+ if netnsExists(ns) {
+ // Terminate processes in old namespaces
+ for _, x := range netnsPids(ns) {
+ log.Printf(" Killing old PID %d", x)
+ err := syscall.Kill(x, syscall.SIGTERM)
+ if err != nil {
+ log.Fatalf("failed to kill %d: %v", x, err)
+ }
+ // Also try SIGHUP to terminate shells which ignore SIGTERM
+ _ = syscall.Kill(x, syscall.SIGHUP)
+ }
+ // Prevent any conflicts with existing data
+ ip("netns", "del", ns)
+ // Don't remove anything in /etc/netns/ as the user might store
+ // configuration there!
+ }
+ ip("netns", "add", ns)
+
+ // Write /etc/netns/$netns/hosts with all known hosts
+ nsCfgPath := filepath.Join("/etc/netns", ns)
+ nsHostsPath := filepath.Join(nsCfgPath, "hosts")
+ log.Printf(" Writing %q", nsHostsPath)
+ err := os.MkdirAll(nsCfgPath, 0755)
+ if err != nil {
+ log.Fatal(err)
+ }
+ err = writeHosts(cfg, nsHostsPath)
+ if err != nil {
+ log.Fatal(err)
+ }
+
+ // Enable IPv4 and IPv6 forwarding
+ ip("netns", "exec", ns, "sysctl", "-q", "net.ipv4.ip_forward=1")
+ ip("netns", "exec", ns, "sysctl", "-q", "net.ipv6.conf.all.forwarding=1")
+
+ ip("-n", ns, "link", "set", "lo", "up")
+ // Extra interface for our loopback addresses; keeping them separate
+ // can make things easier (e.g. using the interface for protocols).
+ lo := "lo2"
+ ip("-n", ns, "link", "add", lo, "type", "dummy")
+ ip("-n", ns, "link", "set", lo, "up")
+ for _, x := range node.Loopbacks {
+ ip("-n", ns, "addr", "add", x.String(), "dev", lo)
+ }
+ }
+
+ log.Printf("Setting up links ...")
+ for _, link := range cfg.Links {
+ nsa := link.A.Node.Name
+ nsb := link.B.Node.Name
+
+ log.Printf(" Link between %q and %q ...", nsa, nsb)
+
+ // Use name of other node for the interface
+ la := nsb
+ lb := nsa
+ // Support multiple links between nodes
+ if ifaceExists(nsa, la) {
+ la = nextFreeIface(nsa, la)
+ }
+ if ifaceExists(nsb, lb) {
+ lb = nextFreeIface(nsb, lb)
+ }
+
+ t := "veth"
+ if link.Layer3 {
+ t = "netkit" // since kernel 6.7, iproute2 6.8
+ }
+ ip("link", "add", "tmpa", "type", t, "peer", "name", "tmpb")
+ ip("link", "set", "tmpa", "netns", nsa)
+ ip("link", "set", "tmpb", "netns", nsb)
+ ip("-n", nsa, "link", "set", "tmpa", "name", la)
+ ip("-n", nsb, "link", "set", "tmpb", "name", lb)
+ for _, x := range link.A.Addrs {
+ ip("-n", nsa, "addr", "add", x.String(), "dev", la)
+ }
+ for _, x := range link.B.Addrs {
+ ip("-n", nsb, "addr", "add", x.String(), "dev", lb)
+ }
+ ip("-n", nsa, "link", "set", la, "up")
+ ip("-n", nsb, "link", "set", lb, "up")
+ }
+
+ log.Printf("Starting cmds ...")
+ for _, node := range cfg.Nodes {
+ log.Printf(" For node %q", node.Name)
+ ns := node.Name
+ for _, cmd := range cfg.Cmds {
+ ip("netns", "exec", ns, "sh", "-c", cmd, "argv0", ns)
+ }
+ }
+}
+
+func ip(args ...string) {
+ xargs := append([]string{"ip"}, args...)
+ log.Printf(" Running %q", xargs)
+
+ cmd := exec.Command("ip", args...)
+ cmd.Stdout = os.Stdout
+ cmd.Stderr = os.Stderr
+ err := cmd.Run()
+ if err != nil {
+ log.Fatalf("failed to run %q: %v", xargs, err)
+ }
+}
+
+func netnsExists(name string) bool {
+ _, err := os.Stat(filepath.Join("/run/netns", name))
+ if err != nil {
+ if os.IsNotExist(err) {
+ return false
+ }
+ log.Fatal(err)
+ }
+ return true
+}
+
+func netnsPids(netns string) []int {
+ args := []string{"netns", "pids", netns}
+ xargs := append([]string{"ip"}, args...)
+
+ cmd := exec.Command("ip", args...)
+ out, err := cmd.Output()
+ if err != nil {
+ log.Fatalf("failed to run %q: %v", xargs, err)
+ }
+
+ isNewline := func(c rune) bool {
+ return c == '\n'
+ }
+
+ var res []int
+ xs := strings.FieldsFunc(string(out), isNewline)
+ for _, x := range xs {
+ y, err := strconv.Atoi(x)
+ if err != nil {
+ log.Fatalf("invalid output from %q: %q: %v", xargs, out, err)
+ }
+ res = append(res, y)
+ }
+ return res
+}
+
+func ifaceExists(netns, name string) bool {
+ args := []string{"-n", netns, "-json", "link"}
+ xargs := append([]string{"ip"}, args...)
+
+ cmd := exec.Command("ip", args...)
+ out, err := cmd.Output()
+ if err != nil {
+ log.Fatalf("failed to run %q: %v", xargs, err)
+ }
+
+ var ifaces []struct {
+ Ifname string `json:"ifname"`
+ }
+ err = json.Unmarshal(out, &ifaces)
+ if err != nil {
+ log.Fatalf("failed to parse output from ip (%q): %v", out, err)
+ }
+
+ for _, x := range ifaces {
+ if x.Ifname == name {
+ return true
+ }
+ }
+ return false
+}
+
+func nextFreeIface(netns, name string) string {
+ i := 2
+ x := name
+ for ifaceExists(netns, x) {
+ x = fmt.Sprintf("%s_%d", name, i)
+ i++
+ }
+ return x
+}
+
+// writeHosts writes a hosts-file (i.e. /etc/hosts) with all known addresses
+// and their corresponding node names.
+func writeHosts(cfg *Config, path string) error {
+ f, err := os.Create(path)
+ if err != nil {
+ return err
+ }
+ defer f.Close()
+ w := bufio.NewWriter(f)
+
+ // Standard entries
+ fmt.Fprintf(w, "127.0.0.1 localhost\n")
+ fmt.Fprintf(w, "::1 localhost ip6-localhost ip6-loopback\n")
+
+ for _, node := range cfg.Nodes {
+ for _, x := range node.Loopbacks {
+ fmt.Fprintf(w, "%s %s-loop\n", x.String(), node.Name)
+ }
+ }
+
+ for _, link := range cfg.Links {
+ for _, x := range link.A.Addrs {
+ fmt.Fprintf(w, "%s %s\n", x.Addr().String(), link.A.Node.Name)
+ }
+ for _, x := range link.B.Addrs {
+ fmt.Fprintf(w, "%s %s\n", x.Addr().String(), link.B.Node.Name)
+ }
+ }
+
+ err = w.Flush()
+ if err != nil {
+ return err
+ }
+ err = f.Sync()
+ if err != nil {
+ return err
+ }
+ return nil
+}
+
+// vi: set noet ts=4 sw=4 sts=4:
ruderich.org/simon / linux-network-namespace-labs / linux-network-namespace-labs.git / commitdiff