Merge branch 'srvlookup'

README.md

@@ -36,12 +36,10 @@ The account data is expected at `~/.sendxmpprc` if no other configuration file l
 
 ```plain
 username: <your_jid>
-jserver: <jabber_server>
-port: <jabber_port>
 password: <your_jabber_password>
 ```
 
-`jserver` and `port` might not be necessary depending on the used server. It is also possible to
+If this is not sufficient to connect you might also specify `jserver` and `port`. It is also possible to
 use a password manager. In this case the `password` setting should be replaced by the `eval_password`
 setting:    
 

connect.go

@@ -0,0 +1,101 @@
+// Copyright 2018 - 2021 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
+
+package main
+
+import (
+	"fmt"
+	"net"
+	"sort"
+	"strings"
+
+	"github.com/mattn/go-xmpp" // BSD-3-Clause
+)
+
+type srv struct {
+	host     string
+	xmpps    bool
+	port     uint16
+	priority uint16
+	weight   uint16
+}
+type srvMixed []srv
+
+type byPriority []srv
+
+func (o byPriority) Len() int      { return len(o) }
+func (o byPriority) Swap(i, j int) { o[i], o[j] = o[j], o[i] }
+func (o byPriority) Less(i, j int) bool {
+	if o[i].priority == o[j].priority {
+		return o[i].weight > o[j].weight
+	} else {
+		return o[i].priority < o[j].priority
+	}
+}
+
+func connect(options xmpp.Options, directTLS bool) (*xmpp.Client, error) {
+
+	// Look up SRV records if server is not specified manually.
+	srvMixed := srvMixed{}
+	if options.Host == "" {
+		server := options.User[strings.LastIndex(options.User, "@")+1:]
+		// Look up xmpp-client SRV records.
+		if _, addrs, err := net.LookupSRV("xmpp-client", "tcp", server); err == nil {
+			if len(addrs) > 0 {
+				for _, adr := range addrs {
+					srvMixed = append(srvMixed, srv{adr.Target, false,
+						adr.Port, adr.Priority, adr.Weight})
+				}
+			}
+		}
+		// Look up xmpps-client SRV records.
+		if _, addrs, err := net.LookupSRV("xmpps-client", "tcp", server); err == nil {
+			if len(addrs) > 0 {
+				for _, adr := range addrs {
+					srvMixed = append(srvMixed, srv{adr.Target, true,
+						adr.Port, adr.Priority, adr.Weight})
+				}
+			}
+		}
+		if len(srvMixed) > 0 {
+			// Sort xmpp- and xmpps-client SRV records according to the priority
+			// and wight.
+			sort.Sort(byPriority(srvMixed))
+			for _, adr := range srvMixed {
+				if !directTLS && !adr.xmpps {
+					// Use StartTLS
+					options.NoTLS = true
+					options.StartTLS = true
+					options.Host = fmt.Sprintf("%s:%d", adr.host, adr.port)
+					// Connect to server
+					client, err := options.NewClient()
+					if err == nil {
+						return client, err
+					}
+				} else if adr.xmpps {
+					// Use direct TLS
+					options.NoTLS = false
+					options.StartTLS = false
+					options.Host = fmt.Sprintf("%s:%d", adr.host, adr.port)
+					// Connect to server
+					client, err := options.NewClient()
+					if err == nil {
+						return client, err
+					}
+
+				}
+			}
+		}
+		// Try port 5222 if no xmpp-client SRV records are provided.
+		options.NoTLS = true
+		options.StartTLS = true
+		options.Host = fmt.Sprintf("%s:%d", server, 5222)
+		// Connect to server
+		client, err := options.NewClient()
+		return client, err
+	}
+	// Connect to server
+	client, err := options.NewClient()
+	return client, err
+}

go-sendxmpp.go

@@ -8,10 +8,8 @@ import (
 	"bufio"
 	"crypto/tls"
 	"errors"
-	"fmt"
 	"io"
 	"log"
-	"net"
 	"os"
 	"os/exec"
 	"os/user"
@@ -292,30 +290,6 @@ func main() {
 		server = *flagServer
 	}
 
-	// Determine server part if no server is specified.
-	if server == "" {
-		server = strings.Split(user, "@")[1]
-
-		// Lookup SRV record for xmpps-client if direct TLS is requested
-		if *flagTLS {
-			if _, addrs, err := net.LookupSRV("xmpps-client", "tcp", server); err == nil {
-
-				if len(addrs) > 0 {
-					// Default to first record
-					server = fmt.Sprintf("%s:%d", addrs[0].Target, addrs[0].Port)
-					defP := addrs[0].Priority
-					for _, adr := range addrs {
-						if adr.Priority < defP {
-							server = fmt.Sprintf("%s:%d", adr.Target, adr.Port)
-							defP = adr.Priority
-						}
-					}
-				}
-			}
-		}
-
-	}
-
 	// Overwrite password if specified via command line flag.
 	if *flagPassword != "" {
 		password = *flagPassword
@@ -334,20 +308,23 @@ func main() {
 
 	// Use ALPN
 	var tlsConfig tls.Config
-	tlsConfig.ServerName = strings.Split(user, "@")[1]
+	tlsConfig.ServerName = user[strings.LastIndex(user, "@")+1:]
 	tlsConfig.NextProtos = append(tlsConfig.NextProtos, "xmpp-client")
 	tlsConfig.InsecureSkipVerify = *flagSkipVerify
 
 	// Set XMPP connection options.
 	options := xmpp.Options{
-		Host:      server,
-		User:      user,
-		Resource:  *flagResource,
-		Password:  password,
-		NoTLS:     !*flagTLS,
-		StartTLS:  !*flagTLS,
-		Debug:     *flagDebug,
-		TLSConfig: &tlsConfig,
+		Host:        server,
+		User:        user,
+		// TODO: Check whether the timeout is reasonable or maybe make
+		// it configurable
+		DialTimeout: 1 * time.Second,
+		Resource:    *flagResource,
+		Password:    password,
+		NoTLS:       !*flagTLS,
+		StartTLS:    !*flagTLS,
+		Debug:       *flagDebug,
+		TLSConfig:   &tlsConfig,
 	}
 
 	// Read message from file.
@@ -359,7 +336,7 @@ func main() {
 	}
 
 	// Connect to server.
-	client, err := options.NewClient()
+	client, err := connect(options, *flagTLS)
 	if err != nil {
 		log.Fatal(err)
 	}