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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License 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.
*/
/*
* Content before git sha 34fdeebefcbf183ed7f916f931aa0586fdaa1b40
* Copyright (c) 2016, The Gocql authors,
* provided under the BSD-3-Clause License.
* See the NOTICE file distributed with this work for additional information.
*/
package gocql
import (
"context"
"crypto/tls"
"fmt"
"net"
"strings"
)
// HostDialer allows customizing connection to cluster nodes.
type HostDialer interface {
// DialHost establishes a connection to the host.
// The returned connection must be directly usable for CQL protocol,
// specifically DialHost is responsible also for setting up the TLS session if needed.
// DialHost should disable write coalescing if the returned net.Conn does not support writev.
// As of Go 1.18, only plain TCP connections support writev, TLS sessions should disable coalescing.
// You can use WrapTLS helper function if you don't need to override the TLS setup.
DialHost(ctx context.Context, host *HostInfo) (*DialedHost, error)
}
// DialedHost contains information about established connection to a host.
type DialedHost struct {
// Conn used to communicate with the server.
Conn net.Conn
// DisableCoalesce disables write coalescing for the Conn.
// If true, the effect is the same as if WriteCoalesceWaitTime was configured to 0.
DisableCoalesce bool
}
// defaultHostDialer dials host in a default way.
type defaultHostDialer struct {
dialer Dialer
tlsConfig *tls.Config
}
func (hd *defaultHostDialer) DialHost(ctx context.Context, host *HostInfo) (*DialedHost, error) {
ip := host.ConnectAddress()
port := host.Port()
if !validIpAddr(ip) {
return nil, fmt.Errorf("host missing connect ip address: %v", ip)
} else if port == 0 {
return nil, fmt.Errorf("host missing port: %v", port)
}
connAddr := host.ConnectAddressAndPort()
conn, err := hd.dialer.DialContext(ctx, "tcp", connAddr)
if err != nil {
return nil, err
}
addr := host.HostnameAndPort()
return WrapTLS(ctx, conn, addr, hd.tlsConfig)
}
func tlsConfigForAddr(tlsConfig *tls.Config, addr string) *tls.Config {
// the TLS config is safe to be reused by connections but it must not
// be modified after being used.
if !tlsConfig.InsecureSkipVerify && tlsConfig.ServerName == "" {
colonPos := strings.LastIndex(addr, ":")
if colonPos == -1 {
colonPos = len(addr)
}
hostname := addr[:colonPos]
// clone config to avoid modifying the shared one.
tlsConfig = tlsConfig.Clone()
tlsConfig.ServerName = hostname
}
return tlsConfig
}
// WrapTLS optionally wraps a net.Conn connected to addr with the given tlsConfig.
// If the tlsConfig is nil, conn is not wrapped into a TLS session, so is insecure.
// If the tlsConfig does not have server name set, it is updated based on the default gocql rules.
func WrapTLS(ctx context.Context, conn net.Conn, addr string, tlsConfig *tls.Config) (*DialedHost, error) {
if tlsConfig != nil {
tlsConfig := tlsConfigForAddr(tlsConfig, addr)
tconn := tls.Client(conn, tlsConfig)
if err := tconn.HandshakeContext(ctx); err != nil {
conn.Close()
return nil, err
}
conn = tconn
}
return &DialedHost{
Conn: conn,
DisableCoalesce: tlsConfig != nil, // write coalescing can't use writev when the connection is wrapped.
}, nil
}
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