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gotosocial/internal/httpclient/client.go

385 lines
11 KiB
Go

// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package httpclient
import (
"context"
"crypto/tls"
"errors"
"fmt"
"io"
"net"
"net/http"
"net/netip"
"runtime"
"strconv"
"strings"
"time"
"codeberg.org/gruf/go-cache/v3"
errorsv2 "codeberg.org/gruf/go-errors/v2"
"codeberg.org/gruf/go-iotools"
"github.com/superseriousbusiness/gotosocial/internal/gtscontext"
"github.com/superseriousbusiness/gotosocial/internal/gtserror"
"github.com/superseriousbusiness/gotosocial/internal/log"
)
var (
// ErrInvalidRequest is returned if a given HTTP request is invalid and cannot be performed.
ErrInvalidRequest = errors.New("invalid http request")
// ErrInvalidNetwork is returned if the request would not be performed over TCP
ErrInvalidNetwork = errors.New("invalid network type")
// ErrReservedAddr is returned if a dialed address resolves to an IP within a blocked or reserved net.
ErrReservedAddr = errors.New("dial within blocked / reserved IP range")
)
// Config provides configuration details for setting up a new
// instance of httpclient.Client{}. Within are a subset of the
// configuration values passed to initialized http.Transport{}
// and http.Client{}, along with httpclient.Client{} specific.
type Config struct {
// MaxOpenConnsPerHost limits the max
// number of open connections to a host.
MaxOpenConnsPerHost int
// AllowRanges allows outgoing
// communications to given IP nets.
AllowRanges []netip.Prefix
// BlockRanges blocks outgoing
// communiciations to given IP nets.
BlockRanges []netip.Prefix
// TLSInsecureSkipVerify can be set to true to
// skip validation of remote TLS certificates.
//
// THIS SHOULD BE USED FOR TESTING ONLY, IF YOU
// TURN THIS ON WHILE RUNNING IN PRODUCTION YOU
// ARE LEAVING YOUR SERVER WIDE OPEN TO ATTACKS!
TLSInsecureSkipVerify bool
// MaxIdleConns: see http.Transport{}.MaxIdleConns.
MaxIdleConns int
// ReadBufferSize: see http.Transport{}.ReadBufferSize.
ReadBufferSize int
// WriteBufferSize: see http.Transport{}.WriteBufferSize.
WriteBufferSize int
// Timeout: see http.Client{}.Timeout.
Timeout time.Duration
// DisableCompression: see http.Transport{}.DisableCompression.
DisableCompression bool
}
// Client wraps an underlying http.Client{} to provide the following:
// - setting a maximum received request body size, returning error on
// large content lengths, and using a limited reader in all other
// cases to protect against forged / unknown content-lengths
// - protection from server side request forgery (SSRF) by only dialing
// out to known public IP prefixes, configurable with allows/blocks
// - retry-backoff logic for error temporary HTTP error responses
// - optional request signing
// - request logging
type Client struct {
client http.Client
badHosts cache.TTLCache[string, struct{}]
retries uint
}
// New returns a new instance of Client initialized using configuration.
func New(cfg Config) *Client {
var c Client
c.retries = 5
d := &net.Dialer{
Timeout: 15 * time.Second,
KeepAlive: 30 * time.Second,
Resolver: &net.Resolver{},
}
if cfg.MaxOpenConnsPerHost <= 0 {
// By default base this value on GOMAXPROCS.
maxprocs := runtime.GOMAXPROCS(0)
cfg.MaxOpenConnsPerHost = maxprocs * 20
}
if cfg.MaxIdleConns <= 0 {
// By default base this value on MaxOpenConns.
cfg.MaxIdleConns = cfg.MaxOpenConnsPerHost * 10
}
// Protect the dialer
// with IP range sanitizer.
d.Control = (&Sanitizer{
Allow: cfg.AllowRanges,
Block: cfg.BlockRanges,
}).Sanitize
// Prepare client fields.
c.client.Timeout = cfg.Timeout
// Prepare transport TLS config.
tlsClientConfig := &tls.Config{
InsecureSkipVerify: cfg.TLSInsecureSkipVerify, //nolint:gosec
}
if tlsClientConfig.InsecureSkipVerify {
// Warn against playing silly buggers.
log.Warn(nil, "http-client.tls-insecure-skip-verify was set to TRUE. "+
"*****THIS SHOULD BE USED FOR TESTING ONLY, IF YOU TURN THIS ON WHILE "+
"RUNNING IN PRODUCTION YOU ARE LEAVING YOUR SERVER WIDE OPEN TO ATTACKS! "+
"IF IN DOUBT, STOP YOUR SERVER *NOW* AND ADJUST YOUR CONFIGURATION!*****",
)
}
// Set underlying HTTP client roundtripper.
c.client.Transport = &signingtransport{http.Transport{
Proxy: http.ProxyFromEnvironment,
ForceAttemptHTTP2: true,
DialContext: d.DialContext,
TLSClientConfig: tlsClientConfig,
MaxIdleConns: cfg.MaxIdleConns,
IdleConnTimeout: 90 * time.Second,
TLSHandshakeTimeout: 10 * time.Second,
ExpectContinueTimeout: 1 * time.Second,
ReadBufferSize: cfg.ReadBufferSize,
WriteBufferSize: cfg.WriteBufferSize,
DisableCompression: cfg.DisableCompression,
}}
// Initiate outgoing bad hosts lookup cache.
c.badHosts = cache.NewTTL[string, struct{}](0, 512, 0)
c.badHosts.SetTTL(time.Hour, false)
if !c.badHosts.Start(time.Minute) {
log.Panic(nil, "failed to start transport controller cache")
}
return &c
}
// Do will essentially perform http.Client{}.Do() with retry-backoff functionality.
func (c *Client) Do(r *http.Request) (rsp *http.Response, err error) {
// First validate incoming request.
if err := ValidateRequest(r); err != nil {
return nil, err
}
// Wrap in our own request
// type for retry-backoff.
req := WrapRequest(r)
if gtscontext.IsFastfail(r.Context()) {
// If the fast-fail flag was set, just
// attempt a single iteration instead of
// following the below retry-backoff loop.
rsp, _, err = c.DoOnce(req)
if err != nil {
return nil, fmt.Errorf("%w (fast fail)", err)
}
return rsp, nil
}
for {
var retry bool
// Perform the http request.
rsp, retry, err = c.DoOnce(req)
if err == nil {
return rsp, nil
}
if !retry {
// reached max retries, don't further backoff
return nil, fmt.Errorf("%w (max retries)", err)
}
// Start new backoff sleep timer.
backoff := time.NewTimer(req.BackOff())
select {
// Request ctx cancelled.
case <-r.Context().Done():
backoff.Stop()
// Return context error.
err = r.Context().Err()
return nil, err
// Backoff for time.
case <-backoff.C:
}
}
}
// DoOnce wraps an underlying http.Client{}.Do() to perform our wrapped request type:
// rewinding response body to permit reuse, signing request data when SignFunc provided,
// marking erroring hosts, updating retry attempt counts and setting backoff from header.
func (c *Client) DoOnce(r *Request) (rsp *http.Response, retry bool, err error) {
if r.attempts > c.retries {
// Ensure request hasn't reached max number of attempts.
err = fmt.Errorf("httpclient: reached max retries (%d)", c.retries)
return
}
// Update no.
// attempts.
r.attempts++
// Reset backoff.
r.backoff = 0
// Perform main routine.
rsp, retry, err = c.do(r)
if rsp != nil {
// Log successful rsp.
r.Entry.Info(rsp.Status)
return
}
// Log any errors.
r.Entry.Error(err)
switch {
case !retry:
// If they were told not to
// retry, also set number of
// attempts to prevent retry.
r.attempts = c.retries + 1
case r.attempts > c.retries:
// On max retries, mark this as
// a "badhost", i.e. is erroring.
c.badHosts.Set(r.Host, struct{}{})
// Ensure retry flag is unset
// when reached max attempts.
retry = false
case c.badHosts.Has(r.Host):
// When retry is still permitted,
// check host hasn't been marked
// as a "badhost", i.e. erroring.
r.attempts = c.retries + 1
retry = false
}
return
}
// do performs the "meat" of DoOnce(), but it's separated out to allow
// easier wrapping of the response, retry, error returns with further logic.
func (c *Client) do(r *Request) (rsp *http.Response, retry bool, err error) {
// Perform the HTTP request.
rsp, err = c.client.Do(r.Request)
if err != nil {
if errorsv2.IsV2(err,
context.DeadlineExceeded,
context.Canceled,
ErrReservedAddr,
) {
// Non-retryable errors.
return nil, false, err
}
if errstr := err.Error(); //
strings.Contains(errstr, "stopped after 10 redirects") ||
strings.Contains(errstr, "tls: ") ||
strings.Contains(errstr, "x509: ") {
// These error types aren't wrapped
// so we have to check the error string.
// All are unrecoverable!
return nil, false, err
}
if dnserr := errorsv2.AsV2[*net.DNSError](err); //
dnserr != nil && dnserr.IsNotFound {
// DNS lookup failure, this domain does not exist
return nil, false, gtserror.SetNotFound(err)
}
// A retryable error.
return nil, true, err
} else if rsp.StatusCode >= 500 ||
rsp.StatusCode == http.StatusTooManyRequests {
// Codes over 500 (and 429: too many requests)
// are generally temporary errors. For these
// we replace the response with a loggable error.
err = fmt.Errorf(`http response: %s`, rsp.Status)
// Search for a provided "Retry-After" header value.
if after := rsp.Header.Get("Retry-After"); after != "" {
// Get cur time.
now := time.Now()
if u, _ := strconv.ParseUint(after, 10, 32); u != 0 {
// An integer no. of backoff seconds was provided.
r.backoff = time.Duration(u) * time.Second // #nosec G115 -- We clamp backoff below.
} else if at, _ := http.ParseTime(after); !at.Before(now) {
// An HTTP formatted future date-time was provided.
r.backoff = at.Sub(now)
}
// Don't let their provided backoff exceed our max.
if max := baseBackoff * time.Duration(c.retries); // #nosec G115 -- We control c.retries.
r.backoff > max {
r.backoff = max
}
}
// Unset + close rsp.
_ = rsp.Body.Close()
return nil, true, err
}
// Seperate the body implementers.
rbody := (io.Reader)(rsp.Body)
cbody := (io.Closer)(rsp.Body)
// Wrap closer to ensure body drained BEFORE close.
cbody = iotools.CloserAfterCallback(cbody, func() {
_, _ = discard.ReadFrom(rbody)
})
// Set the wrapped response body.
rsp.Body = &iotools.ReadCloserType{
Reader: rbody,
Closer: cbody,
}
return rsp, true, nil
}
// cast discard writer to full interface it supports.
var discard = io.Discard.(interface { //nolint
io.Writer
io.StringWriter
io.ReaderFrom
})