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Revert doh (#800) 

* Revert "Require URLs for DOH addresses (#684)"

This reverts commit 8ccae88257.

* Revert "WIP: DNS-over-HTTPS support for Client.Exchange API (#671)"

This reverts commit 64746df23b.

Signed-off-by: Miek Gieben <miek@miek.nl>

* Finish revert of DoH

Signed-off-by: Miek Gieben <miek@miek.nl>

* Add back in the race condition comment

Signed-off-by: Miek Gieben <miek@miek.nl>
This commit is contained in:
Miek Gieben 2018-11-01 20:16:39 +00:00 committed by GitHub
parent 915ca3d5ff
commit 6ae357d393
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 1 additions and 103 deletions
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83
client.go
View File

@ -7,11 +7,8 @@ import (
"context"
"crypto/tls"
"encoding/binary"
"fmt"
"io"
"io/ioutil"
"net"
"net/http"
"strings"
"time"
)
@ -19,8 +16,6 @@ import (
const (
dnsTimeout time.Duration = 2 * time.Second
tcpIdleTimeout time.Duration = 8 * time.Second
dohMimeType = "application/dns-message"
)
// A Conn represents a connection to a DNS server.
@ -44,7 +39,6 @@ type Client struct {
DialTimeout time.Duration // net.DialTimeout, defaults to 2 seconds, or net.Dialer.Timeout if expiring earlier - overridden by Timeout when that value is non-zero
ReadTimeout time.Duration // net.Conn.SetReadTimeout value for connections, defaults to 2 seconds - overridden by Timeout when that value is non-zero
WriteTimeout time.Duration // net.Conn.SetWriteTimeout value for connections, defaults to 2 seconds - overridden by Timeout when that value is non-zero
HTTPClient *http.Client // The http.Client to use for DNS-over-HTTPS
TsigSecret map[string]string // secret(s) for Tsig map[<zonename>]<base64 secret>, zonename must be in canonical form (lowercase, fqdn, see RFC 4034 Section 6.2)
SingleInflight bool // if true suppress multiple outstanding queries for the same Qname, Qtype and Qclass
group singleflight
@ -132,11 +126,6 @@ func (c *Client) Dial(address string) (conn *Conn, err error) {
// attribute appropriately
func (c *Client) Exchange(m *Msg, address string) (r *Msg, rtt time.Duration, err error) {
if !c.SingleInflight {
if c.Net == "https" {
// TODO(tmthrgd): pipe timeouts into exchangeDOH
return c.exchangeDOH(context.TODO(), m, address)
}
return c.exchange(m, address)
}
@ -149,11 +138,6 @@ func (c *Client) Exchange(m *Msg, address string) (r *Msg, rtt time.Duration, er
cl = cl1
}
r, rtt, err, shared := c.group.Do(m.Question[0].Name+t+cl, func() (*Msg, time.Duration, error) {
if c.Net == "https" {
// TODO(tmthrgd): pipe timeouts into exchangeDOH
return c.exchangeDOH(context.TODO(), m, address)
}
return c.exchange(m, address)
})
if r != nil && shared {
@ -199,67 +183,6 @@ func (c *Client) exchange(m *Msg, a string) (r *Msg, rtt time.Duration, err erro
return r, rtt, err
}
func (c *Client) exchangeDOH(ctx context.Context, m *Msg, a string) (r *Msg, rtt time.Duration, err error) {
p, err := m.Pack()
if err != nil {
return nil, 0, err
}
req, err := http.NewRequest(http.MethodPost, a, bytes.NewReader(p))
if err != nil {
return nil, 0, err
}
req.Header.Set("Content-Type", dohMimeType)
req.Header.Set("Accept", dohMimeType)
hc := http.DefaultClient
if c.HTTPClient != nil {
hc = c.HTTPClient
}
if ctx != context.Background() && ctx != context.TODO() {
req = req.WithContext(ctx)
}
t := time.Now()
resp, err := hc.Do(req)
if err != nil {
return nil, 0, err
}
defer closeHTTPBody(resp.Body)
if resp.StatusCode != http.StatusOK {
return nil, 0, fmt.Errorf("dns: server returned HTTP %d error: %q", resp.StatusCode, resp.Status)
}
if ct := resp.Header.Get("Content-Type"); ct != dohMimeType {
return nil, 0, fmt.Errorf("dns: unexpected Content-Type %q; expected %q", ct, dohMimeType)
}
p, err = ioutil.ReadAll(resp.Body)
if err != nil {
return nil, 0, err
}
rtt = time.Since(t)
r = new(Msg)
if err := r.Unpack(p); err != nil {
return r, 0, err
}
// TODO: TSIG? Is it even supported over DoH?
return r, rtt, nil
}
func closeHTTPBody(r io.ReadCloser) error {
io.Copy(ioutil.Discard, io.LimitReader(r, 8<<20))
return r.Close()
}
// ReadMsg reads a message from the connection co.
// If the received message contains a TSIG record the transaction signature
// is verified. This method always tries to return the message, however if an
@ -559,10 +482,6 @@ func DialTimeoutWithTLS(network, address string, tlsConfig *tls.Config, timeout
// context, if present. If there is both a context deadline and a configured
// timeout on the client, the earliest of the two takes effect.
func (c *Client) ExchangeContext(ctx context.Context, m *Msg, a string) (r *Msg, rtt time.Duration, err error) {
if !c.SingleInflight && c.Net == "https" {
return c.exchangeDOH(ctx, m, a)
}
var timeout time.Duration
if deadline, ok := ctx.Deadline(); !ok {
timeout = 0
@ -571,7 +490,7 @@ func (c *Client) ExchangeContext(ctx context.Context, m *Msg, a string) (r *Msg,
}
// not passing the context to the underlying calls, as the API does not support
// context. For timeouts you should set up Client.Dialer and call Client.Exchange.
// TODO(tmthrgd): this is a race condition
// TODO(tmthrgd,miekg): this is a race condition.
c.Dialer = &net.Dialer{Timeout: timeout}
return c.Exchange(m, a)
}

20
client_test.go
View File

@ -589,23 +589,3 @@ func TestConcurrentExchanges(t *testing.T) {
}
}
}
func TestDoHExchange(t *testing.T) {
const addrstr = "https://dns.cloudflare.com/dns-query"
m := new(Msg)
m.SetQuestion("miek.nl.", TypeSOA)
cl := &Client{Net: "https"}
r, _, err := cl.Exchange(m, addrstr)
if err != nil {
t.Fatalf("failed to exchange: %v", err)
}
if r == nil || r.Rcode != RcodeSuccess {
t.Errorf("failed to get an valid answer\n%v", r)
}
// TODO: proper tests for this
}

1
leak_test.go
View File

@ -29,7 +29,6 @@ func interestingGoroutines() (gs []string) {
strings.Contains(stack, "closeWriteAndWait") ||
strings.Contains(stack, "testing.Main(") ||
strings.Contains(stack, "testing.(*T).Run(") ||
strings.Contains(stack, "created by net/http.(*http2Transport).newClientConn") ||
// These only show up with GOTRACEBACK=2; Issue 5005 (comment 28)
strings.Contains(stack, "runtime.goexit") ||
strings.Contains(stack, "created by runtime.gc") ||