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Merge pull request #380 from austinvazquez/vsock
Refactor: pull in firecracker-containerd's internal vsock module as a package
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,208 @@ | ||
| // Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. | ||
| // | ||
| // Licensed under the Apache License, Version 2.0 (the "License"). You may | ||
| // not use this file except in compliance with the License. A copy of the | ||
| // License is located at | ||
| // | ||
| // http://aws.amazon.com/apache2.0/ | ||
| // | ||
| // or in the "license" file accompanying this file. This file is distributed | ||
| // on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either | ||
| // express or implied. See the License for the specific language governing | ||
| // permissions and limitations under the License. | ||
|
|
||
| package vsock | ||
|
|
||
| import ( | ||
| "bufio" | ||
| "context" | ||
| "fmt" | ||
| "net" | ||
| "strings" | ||
| "time" | ||
|
|
||
| "github.com/pkg/errors" | ||
| "github.com/sirupsen/logrus" | ||
| ) | ||
|
|
||
| type Timeout struct { | ||
| DialTimeout time.Duration | ||
| RetryTimeout time.Duration | ||
| RetryInterval time.Duration | ||
| ConnectMsgTimeout time.Duration | ||
| AckMsgTimeout time.Duration | ||
| } | ||
|
|
||
| func DefaultTimeouts() Timeout { | ||
| return Timeout{ | ||
| DialTimeout: 100 * time.Millisecond, | ||
| RetryTimeout: 20 * time.Second, | ||
| RetryInterval: 100 * time.Millisecond, | ||
| ConnectMsgTimeout: 100 * time.Millisecond, | ||
| AckMsgTimeout: 1 * time.Second, | ||
| } | ||
| } | ||
|
|
||
| // Dial connects to the Firecracker host-side vsock at the provided unix path and port. | ||
| // | ||
| // It will retry connect attempts if a temporary error is encountered up to a fixed | ||
| // timeout or the provided request is canceled. | ||
| // | ||
| // udsPath specifies the file system path of the UNIX domain socket. | ||
| // | ||
| // port will be used in the connect message to the firecracker vsock. | ||
| func Dial(ctx context.Context, logger *logrus.Entry, udsPath string, port uint32) (net.Conn, error) { | ||
| return DialTimeout(ctx, logger, udsPath, port, DefaultTimeouts()) | ||
| } | ||
|
|
||
| // DialTimeout acts like Dial but takes a timeout. | ||
| // | ||
| // See func Dial for a description of the udsPath and port parameters. | ||
| func DialTimeout(ctx context.Context, logger *logrus.Entry, udsPath string, port uint32, timeout Timeout) (net.Conn, error) { | ||
| ticker := time.NewTicker(timeout.RetryInterval) | ||
| defer ticker.Stop() | ||
|
|
||
| tickerCh := ticker.C | ||
| var attemptCount int | ||
| for { | ||
| attemptCount++ | ||
| logger := logger.WithField("attempt", attemptCount) | ||
|
|
||
| select { | ||
| case <-ctx.Done(): | ||
| return nil, ctx.Err() | ||
| case <-tickerCh: | ||
| conn, err := tryConnect(logger, udsPath, port, timeout) | ||
| if isTemporaryNetErr(err) { | ||
| err = errors.Wrap(err, "temporary vsock dial failure") | ||
| logger.WithError(err).Debug() | ||
| continue | ||
| } else if err != nil { | ||
| err = errors.Wrap(err, "non-temporary vsock dial failure") | ||
| logger.WithError(err).Error() | ||
| return nil, err | ||
| } | ||
|
|
||
| return conn, nil | ||
| } | ||
| } | ||
| } | ||
|
|
||
| func connectMsg(port uint32) string { | ||
| // The message a host-side connection must write after connecting to a firecracker | ||
| // vsock unix socket in order to establish a connection with a guest-side listener | ||
| // at the provided port number. This is specified in Firecracker documentation: | ||
| // https://github.com/firecracker-microvm/firecracker/blob/main/docs/vsock.md#host-initiated-connections | ||
| return fmt.Sprintf("CONNECT %d\n", port) | ||
| } | ||
|
|
||
| // tryConnect attempts to dial a guest vsock listener at the provided host-side | ||
| // unix socket and provided guest-listener port. | ||
| func tryConnect(logger *logrus.Entry, udsPath string, port uint32, timeout Timeout) (net.Conn, error) { | ||
| conn, err := net.DialTimeout("unix", udsPath, timeout.DialTimeout) | ||
| if err != nil { | ||
| return nil, errors.Wrapf(err, "failed to dial %q within %s", udsPath, timeout.DialTimeout) | ||
| } | ||
|
|
||
| defer func() { | ||
| if err != nil { | ||
| closeErr := conn.Close() | ||
| if closeErr != nil { | ||
| logger.WithError(closeErr).Error( | ||
| "failed to close vsock socket after previous error") | ||
| } | ||
| } | ||
| }() | ||
|
|
||
| msg := connectMsg(port) | ||
| err = tryConnWrite(conn, msg, timeout.ConnectMsgTimeout) | ||
| if err != nil { | ||
| return nil, connectMsgError{ | ||
| cause: errors.Wrapf(err, `failed to write %q within %s`, msg, timeout.ConnectMsgTimeout), | ||
| } | ||
| } | ||
|
|
||
| line, err := tryConnReadUntil(conn, '\n', timeout.AckMsgTimeout) | ||
| if err != nil { | ||
| return nil, ackError{ | ||
| cause: errors.Wrapf(err, `failed to read "OK <port>" within %s`, timeout.AckMsgTimeout), | ||
| } | ||
| } | ||
|
|
||
| // The line would be "OK <assigned_hostside_port>\n", but we don't use the hostside port here. | ||
| // https://github.com/firecracker-microvm/firecracker/blob/main/docs/vsock.md#host-initiated-connections | ||
| if !strings.HasPrefix(line, "OK ") { | ||
| return nil, ackError{ | ||
| cause: errors.Errorf(`expected to read "OK <port>", but instead read %q`, line), | ||
| } | ||
| } | ||
| return conn, nil | ||
| } | ||
|
|
||
| // tryConnReadUntil will try to do a read from the provided conn until the specified | ||
| // end character is encounteed. Returning an error if the read does not complete | ||
| // within the provided timeout. It will reset socket deadlines to none after returning. | ||
| // It's only intended to be used for connect/ack messages, not general purpose reads | ||
| // after the vsock connection is established fully. | ||
| func tryConnReadUntil(conn net.Conn, end byte, timeout time.Duration) (string, error) { | ||
| conn.SetDeadline(time.Now().Add(timeout)) | ||
| defer conn.SetDeadline(time.Time{}) | ||
|
|
||
| return bufio.NewReaderSize(conn, 32).ReadString(end) | ||
| } | ||
|
|
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| // tryConnWrite will try to do a write to the provided conn, returning an error if | ||
| // the write fails, is partial or does not complete within the provided timeout. It | ||
| // will reset socket deadlines to none after returning. It's only intended to be | ||
| // used for connect/ack messages, not general purpose writes after the vsock | ||
| // connection is established fully. | ||
| func tryConnWrite(conn net.Conn, expectedWrite string, timeout time.Duration) error { | ||
| conn.SetDeadline(time.Now().Add(timeout)) | ||
| defer conn.SetDeadline(time.Time{}) | ||
|
|
||
| bytesWritten, err := conn.Write([]byte(expectedWrite)) | ||
| if err != nil { | ||
| return err | ||
| } | ||
| if bytesWritten != len(expectedWrite) { | ||
| return errors.Errorf("incomplete write, expected %d bytes but wrote %d", | ||
| len(expectedWrite), bytesWritten) | ||
| } | ||
|
|
||
| return nil | ||
| } | ||
|
|
||
| type connectMsgError struct { | ||
| cause error | ||
| } | ||
|
|
||
| func (e connectMsgError) Error() string { | ||
| return errors.Wrap(e.cause, "vsock connect message failure").Error() | ||
| } | ||
|
|
||
| func (e connectMsgError) Temporary() bool { | ||
| return false | ||
| } | ||
|
|
||
| type ackError struct { | ||
| cause error | ||
| } | ||
|
|
||
| func (e ackError) Error() string { | ||
| return errors.Wrap(e.cause, "vsock ack message failure").Error() | ||
| } | ||
|
|
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| func (e ackError) Temporary() bool { | ||
| return true | ||
| } | ||
|
|
||
| // isTemporaryNetErr returns whether the provided error is a retriable | ||
| // error, according to the interface defined here: | ||
| // https://golang.org/pkg/net/#Error | ||
| func isTemporaryNetErr(err error) bool { | ||
| terr, ok := err.(interface { | ||
| Temporary() bool | ||
| }) | ||
|
|
||
| return err != nil && ok && terr.Temporary() | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,110 @@ | ||
| // Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. | ||
| // | ||
| // Licensed under the Apache License, Version 2.0 (the "License"). You may | ||
| // not use this file except in compliance with the License. A copy of the | ||
| // License is located at | ||
| // | ||
| // http://aws.amazon.com/apache2.0/ | ||
| // | ||
| // or in the "license" file accompanying this file. This file is distributed | ||
| // on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either | ||
| // express or implied. See the License for the specific language governing | ||
| // permissions and limitations under the License. | ||
|
|
||
| package vsock | ||
|
|
||
| import ( | ||
| "context" | ||
| "net" | ||
| "time" | ||
|
|
||
| "github.com/mdlayher/vsock" | ||
| "github.com/pkg/errors" | ||
| "github.com/sirupsen/logrus" | ||
| ) | ||
|
|
||
| type listener struct { | ||
| listener net.Listener | ||
| port uint32 | ||
| timeout Timeout | ||
| ctx context.Context | ||
| logger *logrus.Entry | ||
| } | ||
|
|
||
| // Listener returns a net.Listener implementation for guest-side Firecracker | ||
| // vsock connections. | ||
| func Listener(ctx context.Context, logger *logrus.Entry, port uint32) (net.Listener, error) { | ||
| l, err := vsock.Listen(port, nil) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
|
||
| return listener{ | ||
| listener: l, | ||
| port: port, | ||
| timeout: DefaultTimeouts(), | ||
| ctx: ctx, | ||
| logger: logger, | ||
| }, nil | ||
| } | ||
|
|
||
| func (l listener) Accept() (net.Conn, error) { | ||
| ctx, cancel := context.WithTimeout(l.ctx, l.timeout.RetryTimeout) | ||
| defer cancel() | ||
|
|
||
| var attemptCount int | ||
| ticker := time.NewTicker(l.timeout.RetryInterval) | ||
| defer ticker.Stop() | ||
| tickerCh := ticker.C | ||
| for { | ||
| attemptCount++ | ||
| logger := l.logger.WithField("attempt", attemptCount) | ||
|
|
||
| select { | ||
| case <-ctx.Done(): | ||
| return nil, ctx.Err() | ||
| case <-tickerCh: | ||
| conn, err := tryAccept(logger, l.listener, l.port) | ||
| if isTemporaryNetErr(err) { | ||
| err = errors.Wrap(err, "temporary vsock accept failure") | ||
| logger.WithError(err).Debug() | ||
| continue | ||
| } else if err != nil { | ||
| err = errors.Wrap(err, "non-temporary vsock accept failure") | ||
| logger.WithError(err).Error() | ||
| return nil, err | ||
| } | ||
|
|
||
| return conn, nil | ||
| } | ||
| } | ||
| } | ||
|
|
||
| func (l listener) Close() error { | ||
| return l.listener.Close() | ||
| } | ||
|
|
||
| func (l listener) Addr() net.Addr { | ||
| return l.listener.Addr() | ||
| } | ||
|
|
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| // tryAccept attempts to accept a single host-side connection from the provided | ||
| // guest-side listener at the provided port. | ||
| func tryAccept(logger *logrus.Entry, listener net.Listener, port uint32) (net.Conn, error) { | ||
| conn, err := listener.Accept() | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
|
||
| defer func() { | ||
| if err != nil { | ||
| closeErr := conn.Close() | ||
| if closeErr != nil { | ||
| logger.WithError(closeErr).Error( | ||
| "failed to close vsock after previous error") | ||
| } | ||
| } | ||
| }() | ||
|
|
||
| return conn, nil | ||
| } |