1 files changed, 281 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/acme/http.go b/vendor/golang.org/x/crypto/acme/http.go
new file mode 100644
index 00000000..a43ce6a5
--- /dev/null
+++ b/vendor/golang.org/x/crypto/acme/http.go
@@ -0,0 +1,281 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package acme
+
+import (
+	"bytes"
+	"context"
+	"crypto"
+	"crypto/rand"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"math/big"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// retryTimer encapsulates common logic for retrying unsuccessful requests.
+// It is not safe for concurrent use.
+type retryTimer struct {
+	// backoffFn provides backoff delay sequence for retries.
+	// See Client.RetryBackoff doc comment.
+	backoffFn func(n int, r *http.Request, res *http.Response) time.Duration
+	// n is the current retry attempt.
+	n int
+}
+
+func (t *retryTimer) inc() {
+	t.n++
+}
+
+// backoff pauses the current goroutine as described in Client.RetryBackoff.
+func (t *retryTimer) backoff(ctx context.Context, r *http.Request, res *http.Response) error {
+	d := t.backoffFn(t.n, r, res)
+	if d <= 0 {
+		return fmt.Errorf("acme: no more retries for %s; tried %d time(s)", r.URL, t.n)
+	}
+	wakeup := time.NewTimer(d)
+	defer wakeup.Stop()
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-wakeup.C:
+		return nil
+	}
+}
+
+func (c *Client) retryTimer() *retryTimer {
+	f := c.RetryBackoff
+	if f == nil {
+		f = defaultBackoff
+	}
+	return &retryTimer{backoffFn: f}
+}
+
+// defaultBackoff provides default Client.RetryBackoff implementation
+// using a truncated exponential backoff algorithm,
+// as described in Client.RetryBackoff.
+//
+// The n argument is always bounded between 1 and 30.
+// The returned value is always greater than 0.
+func defaultBackoff(n int, r *http.Request, res *http.Response) time.Duration {
+	const max = 10 * time.Second
+	var jitter time.Duration
+	if x, err := rand.Int(rand.Reader, big.NewInt(1000)); err == nil {
+		// Set the minimum to 1ms to avoid a case where
+		// an invalid Retry-After value is parsed into 0 below,
+		// resulting in the 0 returned value which would unintentionally
+		// stop the retries.
+		jitter = (1 + time.Duration(x.Int64())) * time.Millisecond
+	}
+	if v, ok := res.Header["Retry-After"]; ok {
+		return retryAfter(v[0]) + jitter
+	}
+
+	if n < 1 {
+		n = 1
+	}
+	if n > 30 {
+		n = 30
+	}
+	d := time.Duration(1<<uint(n-1))*time.Second + jitter
+	if d > max {
+		return max
+	}
+	return d
+}
+
+// retryAfter parses a Retry-After HTTP header value,
+// trying to convert v into an int (seconds) or use http.ParseTime otherwise.
+// It returns zero value if v cannot be parsed.
+func retryAfter(v string) time.Duration {
+	if i, err := strconv.Atoi(v); err == nil {
+		return time.Duration(i) * time.Second
+	}
+	t, err := http.ParseTime(v)
+	if err != nil {
+		return 0
+	}
+	return t.Sub(timeNow())
+}
+
+// resOkay is a function that reports whether the provided response is okay.
+// It is expected to keep the response body unread.
+type resOkay func(*http.Response) bool
+
+// wantStatus returns a function which reports whether the code
+// matches the status code of a response.
+func wantStatus(codes ...int) resOkay {
+	return func(res *http.Response) bool {
+		for _, code := range codes {
+			if code == res.StatusCode {
+				return true
+			}
+		}
+		return false
+	}
+}
+
+// get issues an unsigned GET request to the specified URL.
+// It returns a non-error value only when ok reports true.
+//
+// get retries unsuccessful attempts according to c.RetryBackoff
+// until the context is done or a non-retriable error is received.
+func (c *Client) get(ctx context.Context, url string, ok resOkay) (*http.Response, error) {
+	retry := c.retryTimer()
+	for {
+		req, err := http.NewRequest("GET", url, nil)
+		if err != nil {
+			return nil, err
+		}
+		res, err := c.doNoRetry(ctx, req)
+		switch {
+		case err != nil:
+			return nil, err
+		case ok(res):
+			return res, nil
+		case isRetriable(res.StatusCode):
+			retry.inc()
+			resErr := responseError(res)
+			res.Body.Close()
+			// Ignore the error value from retry.backoff
+			// and return the one from last retry, as received from the CA.
+			if retry.backoff(ctx, req, res) != nil {
+				return nil, resErr
+			}
+		default:
+			defer res.Body.Close()
+			return nil, responseError(res)
+		}
+	}
+}
+
+// post issues a signed POST request in JWS format using the provided key
+// to the specified URL.
+// It returns a non-error value only when ok reports true.
+//
+// post retries unsuccessful attempts according to c.RetryBackoff
+// until the context is done or a non-retriable error is received.
+// It uses postNoRetry to make individual requests.
+func (c *Client) post(ctx context.Context, key crypto.Signer, url string, body interface{}, ok resOkay) (*http.Response, error) {
+	retry := c.retryTimer()
+	for {
+		res, req, err := c.postNoRetry(ctx, key, url, body)
+		if err != nil {
+			return nil, err
+		}
+		if ok(res) {
+			return res, nil
+		}
+		resErr := responseError(res)
+		res.Body.Close()
+		switch {
+		// Check for bad nonce before isRetriable because it may have been returned
+		// with an unretriable response code such as 400 Bad Request.
+		case isBadNonce(resErr):
+			// Consider any previously stored nonce values to be invalid.
+			c.clearNonces()
+		case !isRetriable(res.StatusCode):
+			return nil, resErr
+		}
+		retry.inc()
+		// Ignore the error value from retry.backoff
+		// and return the one from last retry, as received from the CA.
+		if err := retry.backoff(ctx, req, res); err != nil {
+			return nil, resErr
+		}
+	}
+}
+
+// postNoRetry signs the body with the given key and POSTs it to the provided url.
+// The body argument must be JSON-serializable.
+// It is used by c.post to retry unsuccessful attempts.
+func (c *Client) postNoRetry(ctx context.Context, key crypto.Signer, url string, body interface{}) (*http.Response, *http.Request, error) {
+	nonce, err := c.popNonce(ctx, url)
+	if err != nil {
+		return nil, nil, err
+	}
+	b, err := jwsEncodeJSON(body, key, nonce)
+	if err != nil {
+		return nil, nil, err
+	}
+	req, err := http.NewRequest("POST", url, bytes.NewReader(b))
+	if err != nil {
+		return nil, nil, err
+	}
+	req.Header.Set("Content-Type", "application/jose+json")
+	res, err := c.doNoRetry(ctx, req)
+	if err != nil {
+		return nil, nil, err
+	}
+	c.addNonce(res.Header)
+	return res, req, nil
+}
+
+// doNoRetry issues a request req, replacing its context (if any) with ctx.
+func (c *Client) doNoRetry(ctx context.Context, req *http.Request) (*http.Response, error) {
+	res, err := c.httpClient().Do(req.WithContext(ctx))
+	if err != nil {
+		select {
+		case <-ctx.Done():
+			// Prefer the unadorned context error.
+			// (The acme package had tests assuming this, previously from ctxhttp's
+			// behavior, predating net/http supporting contexts natively)
+			// TODO(bradfitz): reconsider this in the future. But for now this
+			// requires no test updates.
+			return nil, ctx.Err()
+		default:
+			return nil, err
+		}
+	}
+	return res, nil
+}
+
+func (c *Client) httpClient() *http.Client {
+	if c.HTTPClient != nil {
+		return c.HTTPClient
+	}
+	return http.DefaultClient
+}
+
+// isBadNonce reports whether err is an ACME "badnonce" error.
+func isBadNonce(err error) bool {
+	// According to the spec badNonce is urn:ietf:params:acme:error:badNonce.
+	// However, ACME servers in the wild return their versions of the error.
+	// See https://tools.ietf.org/html/draft-ietf-acme-acme-02#section-5.4
+	// and https://github.com/letsencrypt/boulder/blob/0e07eacb/docs/acme-divergences.md#section-66.
+	ae, ok := err.(*Error)
+	return ok && strings.HasSuffix(strings.ToLower(ae.ProblemType), ":badnonce")
+}
+
+// isRetriable reports whether a request can be retried
+// based on the response status code.
+//
+// Note that a "bad nonce" error is returned with a non-retriable 400 Bad Request code.
+// Callers should parse the response and check with isBadNonce.
+func isRetriable(code int) bool {
+	return code <= 399 || code >= 500 || code == http.StatusTooManyRequests
+}
+
+// responseError creates an error of Error type from resp.
+func responseError(resp *http.Response) error {
+	// don't care if ReadAll returns an error:
+	// json.Unmarshal will fail in that case anyway
+	b, _ := ioutil.ReadAll(resp.Body)
+	e := &wireError{Status: resp.StatusCode}
+	if err := json.Unmarshal(b, e); err != nil {
+		// this is not a regular error response:
+		// populate detail with anything we received,
+		// e.Status will already contain HTTP response code value
+		e.Detail = string(b)
+		if e.Detail == "" {
+			e.Detail = resp.Status
+		}
+	}
+	return e.error(resp.Header)
+}