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// Copyright Martin Dosch.
// Use of this source code is governed by the BSD-2-clause
// license that can be found in the LICENSE file.
package main
import (
"fmt"
"log/slog"
"net"
"os"
"strings"
"time"
"github.com/xmppo/go-xmpp" // BSD-3-Clause
"golang.org/x/net/idna" // BSD-3-Clause
"salsa.debian.org/mdosch/xmppsrv" // BSD-2-Clause
)
func connect(options xmpp.Options, directTLS bool, anon bool, retryWait int, retryMax int) (client *xmpp.Client, err error) {
var server string
proxy := os.Getenv("HTTP_PROXY")
slog.Info("getting environment variable:", "HTTP_PROXY", proxy)
if !anon {
server = options.User[strings.Index(options.User, "@")+1:]
} else {
server = options.User
}
retry := true
for i := 0; retry; i++ {
// Look up SRV records or hostmeta2 if server is not specified manually
// or if anon authentication is used.
if options.Host == "" || anon {
// Don't do SRV or hostmeta2 look ups if proxy is set.
// TODO: 2024-10-30: Support hostmeta2 look ups using proxy.
if proxy == "" {
// Look up xmpp-client SRV records.
slog.Info("looking up client SRV records for", "server", server)
serverASCII, err := idna.ToASCII(server)
if err != nil {
return client, err
}
srvMixed, err := xmppsrv.LookupClient(serverASCII)
if len(srvMixed) > 0 && err == nil {
for _, adr := range srvMixed {
switch {
case directTLS && adr.Type == "xmpp-client":
slog.Info("skipping as direct TLS is requested:", "type", adr.Type,
"target", adr.Target, "port", adr.Port)
continue
case adr.Type == "xmpp-client":
// Use StartTLS
options.NoTLS = true
slog.Info("received SRV record:", "type", adr.Type, "target", adr.Target, "port", adr.Port)
slog.Info("setting xmpp connection option:", "NoTLS", options.NoTLS)
slog.Info("setting xmpp connection option:", "StartTLS", options.StartTLS)
options.StartTLS = true
case adr.Type == "xmpps-client":
// Use direct TLS
options.NoTLS = false
options.StartTLS = false
slog.Info("received SRV record::", "type", adr.Type, "target", adr.Target, "port", adr.Port)
slog.Info("setting xmpp connection option:", "NoTLS", options.NoTLS)
slog.Info("setting xmpp connection option:", "StartTLS", options.StartTLS)
default:
continue
}
options.Host = net.JoinHostPort(adr.Target, fmt.Sprint(adr.Port))
// Connect to server
slog.Info("connecting to", "host", options.Host)
client, err = options.NewClient()
if err == nil || strings.Contains(err.Error(), "not-authorized") {
// Don't try to connect on other port if error contains
// "not-authorized".
return client, err
}
slog.Info("connecting failed")
}
}
// Look up hostmeta2 file.
slog.Info("looking up host meta 2 for", "server", server)
hm2, httpStatus, err := xmppsrv.LookupHostmeta2(serverASCII)
if httpStatus != 404 && err != nil {
for _, link := range hm2.Links {
if link.Rel == nsC2SdTLS {
options.NoTLS = false
options.StartTLS = false
slog.Info("setting xmpp connection option:", "NoTLS", options.NoTLS)
slog.Info("setting xmpp connection option:", "StartTLS", options.StartTLS)
options.Host = net.JoinHostPort(link.Sni, fmt.Sprint(link.Port))
// Connect to server
slog.Info("connecting to", "host", options.Host)
client, err = options.NewClient()
if err == nil || strings.Contains(err.Error(), "not-authorized") {
// Don't try to connect on other port if error contains
// "not-authorized".
return client, err
}
}
}
}
}
}
_, port, _ := net.SplitHostPort(options.Host)
if port == "" {
if options.Host == "" {
options.Host = server
}
// Try port 5223 if directTLS is set and no port is provided.
if directTLS {
options.NoTLS = false
options.StartTLS = false
options.Host = net.JoinHostPort(options.Host, "5223")
slog.Info("trying direct TLS fallback on port 5223")
} else {
// Try port 5222 if no port is provided and directTLS is not set.
options.NoTLS = true
options.StartTLS = true
options.Host = net.JoinHostPort(options.Host, "5222")
slog.Info("trying StartTLS fallback on port 5222")
}
}
// Connect to server
slog.Info("connecting to", "host", options.Host)
client, err = options.NewClient()
if err == nil {
return
}
if retryWait == 0 {
slog.Info("giving up trying to connect…")
break
}
if retryMax != 0 && retryMax == i {
retry = false
}
// Reset options.Host as otherwise DNS look up is skipped.
options.Host = ""
sleepDuration := time.Duration(retryWait) * time.Second
slog.Info("connecting failed, retry after", "sleep", sleepDuration)
time.Sleep(sleepDuration)
slog.Info("connecting to server:", "retry", i)
}
return client, fmt.Errorf("connect: failed to connect to server: %v", err)
}
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