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net/ping,netcheck: add v6 pinging capabilities to pinger (#7971)

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This change adds a v6conn to the pinger to enable sending pings to v6
addrs.

Updates #7826

Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>
This commit is contained in:
Charlotte Brandhorst-Satzkorn
2023-04-26 15:59:37 -07:00
committed by GitHub
parent 1145b9751d
commit 161d1d281a
4 changed files with 245 additions and 63 deletions
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171
net/ping/ping.go
View File

@ -11,16 +11,25 @@ import (
"crypto/rand"
"encoding/binary"
"fmt"
"io"
"log"
"net"
"net/netip"
"sync"
"sync/atomic"
"time"
"golang.org/x/net/icmp"
"golang.org/x/net/ipv4"
"tailscale.com/net/netmon"
"tailscale.com/net/netns"
"golang.org/x/net/ipv6"
"tailscale.com/types/logger"
"tailscale.com/util/mak"
"tailscale.com/util/multierr"
)
const (
v4Type = "ip4:icmp"
v6Type = "ip6:icmp"
)
type response struct {
@ -33,12 +42,21 @@ type outstanding struct {
data []byte
}
// PacketListener defines the interface required to listen to packages
// on an address.
type ListenPacketer interface {
ListenPacket(ctx context.Context, typ string, addr string) (net.PacketConn, error)
}
// Pinger represents a set of ICMP echo requests to be sent at a single time.
//
// A new instance should be created for each concurrent set of ping requests;
// this type should not be reused.
type Pinger struct {
c net.PacketConn
lp ListenPacketer
// closed guards against send incrementing the waitgroup concurrently with close.
closed atomic.Bool
Logf logger.Logf
Verbose bool
timeNow func() time.Time
@ -46,16 +64,37 @@ type Pinger struct {
wg sync.WaitGroup
// Following fields protected by mu
mu sync.Mutex
mu sync.Mutex
// conns is a map of "type" to net.PacketConn, type is either
// "ip4:icmp" or "ip6:icmp"
conns map[string]net.PacketConn
seq uint16 // uint16 per RFC 792
pings map[uint16]outstanding
}
// New creates a new Pinger. The Context provided will be used to create
// network listeners, and to set an absolute deadline (if any) on the net.Conn
// The netMon parameter is optional; if non-nil it's used to do faster interface lookups.
func New(ctx context.Context, logf logger.Logf, netMon *netmon.Monitor) (*Pinger, error) {
p, err := newUnstarted(ctx, logf, netMon)
func New(ctx context.Context, logf logger.Logf, lp ListenPacketer) *Pinger {
var id [2]byte
if _, err := io.ReadFull(rand.Reader, id[:]); err != nil {
panic("net/ping: New:" + err.Error())
}
return &Pinger{
lp: lp,
Logf: logf,
timeNow: time.Now,
id: binary.LittleEndian.Uint16(id[:]),
pings: make(map[uint16]outstanding),
}
}
func (p *Pinger) mkconn(ctx context.Context, typ, addr string) (net.PacketConn, error) {
if p.closed.Load() {
return nil, net.ErrClosed
}
c, err := p.lp.ListenPacket(ctx, typ, addr)
if err != nil {
return nil, err
}
@ -64,35 +103,36 @@ func New(ctx context.Context, logf logger.Logf, netMon *netmon.Monitor) (*Pinger
// applies to all future I/O, so we only need to do it once.
deadline, ok := ctx.Deadline()
if ok {
if err := p.c.SetReadDeadline(deadline); err != nil {
if err := c.SetReadDeadline(deadline); err != nil {
return nil, err
}
}
p.wg.Add(1)
go p.run(ctx)
return p, nil
go p.run(ctx, c, typ)
return c, err
}
func newUnstarted(ctx context.Context, logf logger.Logf, netMon *netmon.Monitor) (*Pinger, error) {
var id [2]byte
_, err := rand.Read(id[:])
// getConn creates or returns a conn matching typ which is ip4:icmp
// or ip6:icmp.
func (p *Pinger) getConn(ctx context.Context, typ string) (net.PacketConn, error) {
p.mu.Lock()
defer p.mu.Unlock()
if c, ok := p.conns[typ]; ok {
return c, nil
}
var addr = "0.0.0.0"
if typ == v6Type {
addr = "::"
}
c, err := p.mkconn(ctx, typ, addr)
if err != nil {
return nil, err
}
conn, err := netns.Listener(logf, netMon).ListenPacket(ctx, "ip4:icmp", "0.0.0.0")
if err != nil {
return nil, err
}
return &Pinger{
c: conn,
Logf: logf,
timeNow: time.Now,
id: binary.LittleEndian.Uint16(id[:]),
pings: make(map[uint16]outstanding),
}, nil
mak.Set(&p.conns, typ, c)
return c, nil
}
func (p *Pinger) logf(format string, a ...any) {
@ -110,13 +150,34 @@ func (p *Pinger) vlogf(format string, a ...any) {
}
func (p *Pinger) Close() error {
err := p.c.Close()
p.closed.Store(true)
p.mu.Lock()
conns := p.conns
p.conns = nil
p.mu.Unlock()
var errors []error
for _, c := range conns {
if err := c.Close(); err != nil {
errors = append(errors, err)
}
}
p.wg.Wait()
return err
p.cleanupOutstanding()
return multierr.New(errors...)
}
func (p *Pinger) run(ctx context.Context) {
func (p *Pinger) run(ctx context.Context, conn net.PacketConn, typ string) {
defer p.wg.Done()
defer func() {
conn.Close()
p.mu.Lock()
delete(p.conns, typ)
p.mu.Unlock()
}()
buf := make([]byte, 1500)
loop:
@ -127,7 +188,7 @@ loop:
default:
}
n, addr, err := p.c.ReadFrom(buf)
n, _, err := conn.ReadFrom(buf)
if err != nil {
// Ignore temporary errors; everything else is fatal
if netErr, ok := err.(net.Error); !ok || !netErr.Temporary() {
@ -136,10 +197,8 @@ loop:
continue
}
p.handleResponse(buf[:n], addr, p.timeNow())
p.handleResponse(buf[:n], p.timeNow(), typ)
}
p.cleanupOutstanding()
}
func (p *Pinger) cleanupOutstanding() {
@ -151,16 +210,28 @@ func (p *Pinger) cleanupOutstanding() {
}
}
func (p *Pinger) handleResponse(buf []byte, addr net.Addr, now time.Time) {
const ProtocolICMP = 1
m, err := icmp.ParseMessage(ProtocolICMP, buf)
func (p *Pinger) handleResponse(buf []byte, now time.Time, typ string) {
// We need to handle responding to both IPv4
// and IPv6.
var icmpType icmp.Type
switch typ {
case v4Type:
icmpType = ipv4.ICMPTypeEchoReply
case v6Type:
icmpType = ipv6.ICMPTypeEchoReply
default:
p.vlogf("handleResponse: unknown icmp.Type")
return
}
m, err := icmp.ParseMessage(icmpType.Protocol(), buf)
if err != nil {
p.vlogf("handleResponse: invalid packet: %v", err)
return
}
if m.Type != ipv4.ICMPTypeEchoReply {
p.vlogf("handleResponse: wanted m.Type=%d; got %d", ipv4.ICMPTypeEchoReply, m.Type)
if m.Type != icmpType {
p.vlogf("handleResponse: wanted m.Type=%d; got %d", icmpType, m.Type)
return
}
@ -212,9 +283,27 @@ func (p *Pinger) Send(ctx context.Context, dest net.Addr, data []byte) (time.Dur
seq := p.seq
p.mu.Unlock()
// Check whether the address is IPv4 or IPv6 to
// determine the icmp.Type and conn to use.
var conn net.PacketConn
var icmpType icmp.Type = ipv4.ICMPTypeEcho
ap, err := netip.ParseAddr(dest.String())
if err != nil {
return 0, err
}
if ap.Is6() {
icmpType = ipv6.ICMPTypeEchoRequest
conn, err = p.getConn(ctx, v6Type)
} else {
conn, err = p.getConn(ctx, v4Type)
}
if err != nil {
return 0, err
}
m := icmp.Message{
Type: ipv4.ICMPTypeEcho,
Code: 0,
Type: icmpType,
Code: icmpType.Protocol(),
Body: &icmp.Echo{
ID: int(p.id),
Seq: int(seq),
@ -234,7 +323,7 @@ func (p *Pinger) Send(ctx context.Context, dest net.Addr, data []byte) (time.Dur
p.mu.Unlock()
start := p.timeNow()
n, err := p.c.WriteTo(b, dest)
n, err := conn.WriteTo(b, dest)
if err != nil {
return 0, err
} else if n != len(b) {