Fast and extensible multi-platform HTTP/1-2-3 web server with automatic HTTPS
Mirrored from https://github.com/Slazee/caddy.git
Synced Nov 11, 01:00 UTC
| 1 | // Copyright 2015 Matthew Holt and The Caddy Authors |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | package reverseproxy |
| 16 | |
| 17 | import ( |
| 18 | "context" |
| 19 | "errors" |
| 20 | "io" |
| 21 | "sync" |
| 22 | "time" |
| 23 | |
| 24 | "github.com/quic-go/webtransport-go" |
| 25 | "go.uber.org/zap" |
| 26 | ) |
| 27 | |
| 28 | // runWebTransportPump bridges two WebTransport sessions so that every |
| 29 | // bidirectional stream, unidirectional stream, and datagram opened on one |
| 30 | // side is mirrored onto the other. It blocks until both sessions end. |
| 31 | // logger must be non-nil; callers pass either h.logger or zap.NewNop(). |
| 32 | // |
| 33 | // Close propagation: when either session ends with a SessionError, the |
| 34 | // error code and message are forwarded to the peer via CloseWithError. |
| 35 | // When a session ends without a SessionError (context cancelled or |
| 36 | // connection dropped), the peer is closed with code 0. Each side's close |
| 37 | // is propagated at most once. |
| 38 | // |
| 39 | // EXPERIMENTAL: this helper is an internal building block for the |
| 40 | // WebTransport reverse-proxy transport and may change. |
| 41 | func runWebTransportPump(clientSess, upstreamSess *webtransport.Session, logger *zap.Logger) { |
| 42 | p := &webtransportPump{ |
| 43 | client: clientSess, |
| 44 | upstream: upstreamSess, |
| 45 | logger: logger, |
| 46 | } |
| 47 | p.run() |
| 48 | } |
| 49 | |
| 50 | type webtransportPump struct { |
| 51 | client, upstream *webtransport.Session |
| 52 | logger *zap.Logger |
| 53 | |
| 54 | closeClientOnce sync.Once |
| 55 | closeUpstreamOnce sync.Once |
| 56 | // streams owns every bidi and uni splice. run waits for them after |
| 57 | // the accept loops return so the handler does not unregister the |
| 58 | // session while a copy is still unwinding. |
| 59 | streams sync.WaitGroup |
| 60 | } |
| 61 | |
| 62 | func (p *webtransportPump) run() { |
| 63 | var wg sync.WaitGroup |
| 64 | closeClient := func(cause error) { |
| 65 | p.propagateClose(p.client, p.upstream, &p.closeClientOnce, cause) |
| 66 | } |
| 67 | closeUpstream := func(cause error) { |
| 68 | p.propagateClose(p.upstream, p.client, &p.closeUpstreamOnce, cause) |
| 69 | } |
| 70 | |
| 71 | wg.Go(func() { p.acceptBidi(p.client, p.upstream, closeUpstream) }) |
| 72 | wg.Go(func() { p.acceptBidi(p.upstream, p.client, closeClient) }) |
| 73 | wg.Go(func() { p.acceptUni(p.client, p.upstream, closeUpstream) }) |
| 74 | wg.Go(func() { p.acceptUni(p.upstream, p.client, closeClient) }) |
| 75 | wg.Go(func() { p.pumpDatagrams(p.client, p.upstream, closeUpstream) }) |
| 76 | wg.Go(func() { p.pumpDatagrams(p.upstream, p.client, closeClient) }) |
| 77 | wg.Wait() |
| 78 | p.streams.Wait() |
| 79 | } |
| 80 | |
| 81 | // propagateClose closes target once with a code/message derived from |
| 82 | // cause. If cause carries a *webtransport.SessionError (the common case — |
| 83 | // Accept{,Uni}Stream returns it directly when the peer closed the |
| 84 | // session), its code/message are used. Otherwise, typically the |
| 85 | // datagram loop won the race to detect the close and its error lacks |
| 86 | // the code, so we fall back to probing peer for its stored close state |
| 87 | // via a short AcceptStream. |
| 88 | func (p *webtransportPump) propagateClose(target, peer *webtransport.Session, once *sync.Once, cause error) { |
| 89 | once.Do(func() { |
| 90 | code, msg, ok := closeCodeFromErr(cause) |
| 91 | if !ok { |
| 92 | code, msg, _ = codeFromSession(peer) |
| 93 | } |
| 94 | _ = target.CloseWithError(code, msg) |
| 95 | }) |
| 96 | } |
| 97 | |
| 98 | // codeFromSession reads the peer's stored SessionError by waiting for the |
| 99 | // session's context to be cancelled — by that point webtransport-go has |
| 100 | // set closeErr — and then calling AcceptStream, which returns it via its |
| 101 | // initial closeErr check without blocking. Used only on the close path |
| 102 | // when the caller's own error didn't carry the code (e.g. ReceiveDatagram |
| 103 | // returned a context error). |
| 104 | func codeFromSession(sess *webtransport.Session) (webtransport.SessionErrorCode, string, bool) { |
| 105 | select { |
| 106 | case <-sess.Context().Done(): |
| 107 | case <-time.After(200 * time.Millisecond): |
| 108 | return 0, "", false |
| 109 | } |
| 110 | _, err := sess.AcceptStream(context.Background()) |
| 111 | return closeCodeFromErr(err) |
| 112 | } |
| 113 | |
| 114 | // acceptBidi loops on src.AcceptStream and, for each accepted |
| 115 | // bidirectional stream, opens a matching stream on dst and pipes bytes in |
| 116 | // both directions. When src ends, it invokes propagate to close dst. |
| 117 | func (p *webtransportPump) acceptBidi(src, dst *webtransport.Session, propagate func(error)) { |
| 118 | ctx := src.Context() |
| 119 | for { |
| 120 | srcStr, err := src.AcceptStream(ctx) |
| 121 | if err != nil { |
| 122 | propagate(err) |
| 123 | return |
| 124 | } |
| 125 | dstStr, err := dst.OpenStreamSync(ctx) |
| 126 | if err != nil { |
| 127 | p.logger.Debug("webtransport: open upstream bidi failed", zap.Error(err)) |
| 128 | srcStr.CancelRead(0) |
| 129 | srcStr.CancelWrite(0) |
| 130 | propagate(err) |
| 131 | return |
| 132 | } |
| 133 | p.streams.Go(func() { p.spliceBidi(srcStr, dstStr) }) |
| 134 | } |
| 135 | } |
| 136 | |
| 137 | // spliceBidi copies bytes between two bidirectional streams until both |
| 138 | // sides observe EOF or an error. |
| 139 | func (p *webtransportPump) spliceBidi(a, b *webtransport.Stream) { |
| 140 | var wg sync.WaitGroup |
| 141 | wg.Go(func() { |
| 142 | p.spliceOne(b, a, "webtransport bidi splice a->b") |
| 143 | }) |
| 144 | wg.Go(func() { |
| 145 | p.spliceOne(a, b, "webtransport bidi splice b->a") |
| 146 | }) |
| 147 | wg.Wait() |
| 148 | } |
| 149 | |
| 150 | // acceptUni loops on src.AcceptUniStream and, for each stream, opens a |
| 151 | // matching unidirectional stream on dst and pipes bytes through. |
| 152 | func (p *webtransportPump) acceptUni(src, dst *webtransport.Session, propagate func(error)) { |
| 153 | ctx := src.Context() |
| 154 | for { |
| 155 | recv, err := src.AcceptUniStream(ctx) |
| 156 | if err != nil { |
| 157 | propagate(err) |
| 158 | return |
| 159 | } |
| 160 | send, err := dst.OpenUniStreamSync(ctx) |
| 161 | if err != nil { |
| 162 | p.logger.Debug("webtransport: open upstream uni failed", zap.Error(err)) |
| 163 | recv.CancelRead(0) |
| 164 | propagate(err) |
| 165 | return |
| 166 | } |
| 167 | p.streams.Go(func() { |
| 168 | if _, err := streamCopy(send, recv); err != nil && !isExpectedEOF(err) { |
| 169 | p.logger.Debug("webtransport uni splice", zap.Error(err)) |
| 170 | recv.CancelRead(0) |
| 171 | send.CancelWrite(0) |
| 172 | } |
| 173 | _ = send.Close() |
| 174 | }) |
| 175 | } |
| 176 | } |
| 177 | |
| 178 | // spliceOne copies src into dst. A hard error cancels both reads so the |
| 179 | // opposite copy, which may be blocked in Read, can finish. A clean EOF |
| 180 | // only closes dst's write side; the other direction may still be sending. |
| 181 | func (p *webtransportPump) spliceOne(dst, src *webtransport.Stream, failMsg string) { |
| 182 | if _, err := streamCopy(dst, src); err != nil && !isExpectedEOF(err) { |
| 183 | p.logger.Debug(failMsg, zap.Error(err)) |
| 184 | src.CancelRead(0) |
| 185 | dst.CancelRead(0) |
| 186 | } |
| 187 | _ = dst.Close() |
| 188 | } |
| 189 | |
| 190 | // pumpDatagrams forwards datagrams from src to dst until src ends. Unlike |
| 191 | // streams, datagrams are unreliable, so SendDatagram errors are best-effort |
| 192 | // and are not treated as fatal for the session. |
| 193 | func (p *webtransportPump) pumpDatagrams(src, dst *webtransport.Session, propagate func(error)) { |
| 194 | ctx := src.Context() |
| 195 | for { |
| 196 | data, err := src.ReceiveDatagram(ctx) |
| 197 | if err != nil { |
| 198 | propagate(err) |
| 199 | return |
| 200 | } |
| 201 | if err := dst.SendDatagram(data); err != nil { |
| 202 | p.logger.Debug("webtransport send datagram", zap.Error(err)) |
| 203 | } |
| 204 | } |
| 205 | } |
| 206 | |
| 207 | // streamCopy is io.Copy. Tests replace it to hold a worker open across shutdown. |
| 208 | var streamCopy = io.Copy |
| 209 | |
| 210 | // closeCodeFromErr extracts a SessionErrorCode + message from err if it |
| 211 | // represents a session close. The bool is false when err is nil or not |
| 212 | // a *webtransport.SessionError. |
| 213 | func closeCodeFromErr(err error) (webtransport.SessionErrorCode, string, bool) { |
| 214 | sessErr, ok := errors.AsType[*webtransport.SessionError](err) |
| 215 | if ok { |
| 216 | return sessErr.ErrorCode, sessErr.Message, true |
| 217 | } |
| 218 | return 0, "", false |
| 219 | } |
| 220 | |
| 221 | // isExpectedEOF reports whether err is one we don't need to log: plain |
| 222 | // EOF, context cancellation, or an already-closed session. |
| 223 | func isExpectedEOF(err error) bool { |
| 224 | if err == nil { |
| 225 | return true |
| 226 | } |
| 227 | if errors.Is(err, io.EOF) || errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) { |
| 228 | return true |
| 229 | } |
| 230 | var sessErr *webtransport.SessionError |
| 231 | return errors.As(err, &sessErr) |
| 232 | } |