mirror of
https://github.com/sigcn/pg.git
synced 2025-10-05 18:36:50 +08:00
106 lines
2.3 KiB
Go
106 lines
2.3 KiB
Go
package netlink
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import (
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"context"
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"encoding/hex"
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"fmt"
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"log/slog"
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"net"
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"os"
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"os/exec"
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"slices"
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"syscall"
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"golang.org/x/net/route"
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)
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func RouteSubscribe(ctx context.Context, ch chan<- RouteUpdate) error {
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fd, err := syscall.Socket(syscall.AF_ROUTE, syscall.SOCK_RAW, syscall.AF_UNSPEC)
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if err != nil {
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return fmt.Errorf("syscall socket: %w", err)
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}
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go func() {
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err := runRouteMsgReadLoop(fd, ch)
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if err != nil {
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slog.Error("RouteSubscribe", "err", fmt.Errorf("msg read loop exited: %w", err))
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}
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}()
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go func() {
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<-ctx.Done()
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syscall.Close(fd)
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close(ch)
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}()
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return nil
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}
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func runRouteMsgReadLoop(fd int, ch chan<- RouteUpdate) error {
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buf := make([]byte, os.Getpagesize())
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for {
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n, err := syscall.Read(fd, buf)
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if err != nil {
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return fmt.Errorf("syscall read: %w", err)
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}
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buf[0] = 254
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msgs, err := route.ParseRIB(route.RIBTypeRoute, buf[:254])
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if err != nil {
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slog.Warn("RouteParseRIB", "err", err, "msglen1", n, "msglen2", buf[0], "msg", hex.EncodeToString(buf[:n]))
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continue
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}
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for _, msg := range msgs {
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m, ok := msg.(*route.RouteMessage)
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if !ok {
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continue
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}
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if !slices.Contains([]int{syscall.RTM_ADD, syscall.RTM_DELETE}, m.Type) {
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continue
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}
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var dst net.IPNet
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var via []byte
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for _, addr := range m.Addrs {
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var ip []byte
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switch v := addr.(type) {
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case *route.Inet4Addr:
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ip = v.IP[:]
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case *route.Inet6Addr:
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ip = v.IP[:]
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case *route.LinkAddr:
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ip = net.IPv6loopback
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default:
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continue
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}
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if dst.IP == nil {
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dst.IP = ip
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continue
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}
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if via == nil {
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via = ip
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continue
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}
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if dst.Mask == nil {
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dst.Mask = ip
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break
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}
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}
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ch <- RouteUpdate{
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New: buf[3] == 1,
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Dst: &dst,
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Via: via,
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}
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}
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}
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}
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func AddRoute(ifName string, to *net.IPNet, _ net.IP) error {
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if to.IP.To4() == nil { // ipv6
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return exec.Command("route", "-qn", "add", "-inet6", to.String(), "-iface", ifName).Run()
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}
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return exec.Command("route", "-qn", "add", "-inet", to.String(), "-iface", ifName).Run()
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}
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func DelRoute(_ string, to *net.IPNet, _ net.IP) error {
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if to.IP.To4() == nil { // ipv6
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return exec.Command("route", "-qn", "delete", "-inet6", to.String()).Run()
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}
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return exec.Command("route", "-qn", "delete", "-inet", to.String()).Run()
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}
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