first commit

Author: ryuichi1208

README.md

@@ -1 +1,95 @@
-# go-sip
+# Go-SIP
+
+A simple SIP server implemented in Go.
+
+## Features
+
+- Reception and processing of SIP messages
+- Handling of REGISTER, INVITE, and BYE requests
+- Generation of SIP responses
+- Configuration via config file
+
+## Usage
+
+### Starting the Server
+
+Start the server with the following command:
+
+```
+go run main.go
+```
+
+By default, the server listens on UDP port 5060.
+
+### Configuration File
+
+The server reads a configuration file named `config.json` by default. You can specify a different configuration file:
+
+```
+go run main.go -config myconfig.json
+```
+
+To generate a default configuration file:
+
+```
+go run main.go -generate-config
+```
+
+Example configuration file:
+
+```json
+{
+  "server": {
+    "port": "5060",
+    "log_level": "info",
+    "bind_addr": "0.0.0.0"
+  }
+}
+```
+
+### Command Line Options
+
+Override configuration file values with command line options:
+
+```
+go run main.go -port 5080 -bind 127.0.0.1
+```
+
+All options:
+
+- `-config <file>` - Path to configuration file
+- `-generate-config` - Generate default config file and exit
+- `-port <port>` - Override port number
+- `-bind <addr>` - Override bind address
+
+## Test Client
+
+A simple SIP client is included for testing:
+
+```
+go run examples/sip_client.go
+```
+
+The client supports the following commands:
+
+- register: Register a user
+- invite: Initiate a call
+- bye: End a call
+- exit: Exit the client
+
+You can specify the server address and username:
+
+```
+go run examples/sip_client.go -server 127.0.0.1:5060 -user alice
+```
+
+## Supported SIP Methods
+
+- REGISTER: User registration
+- INVITE: Call initiation
+- BYE: Call termination
+- ACK: Acknowledgment handling
+
+## Disclaimer
+
+This is a simple SIP server for demonstration purposes and is not recommended for production use. A real SIP server requires additional features such as authentication, security, and full SIP specification support.

config.json

@@ -0,0 +1,7 @@
+{
+  "server": {
+    "port": "5060",
+    "log_level": "info",
+    "bind_addr": "0.0.0.0"
+  }
+}

config/config.go

@@ -0,0 +1,70 @@
+package config
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+)
+
+// Config represents the SIP server configuration
+type Config struct {
+	Server ServerConfig `json:"server"`
+}
+
+// ServerConfig holds server-specific settings
+type ServerConfig struct {
+	Port     string `json:"port"`
+	LogLevel string `json:"log_level"`
+	BindAddr string `json:"bind_addr"`
+}
+
+// DefaultConfig returns the default configuration
+func DefaultConfig() *Config {
+	return &Config{
+		Server: ServerConfig{
+			Port:     "5060",
+			LogLevel: "info",
+			BindAddr: "0.0.0.0",
+		},
+	}
+}
+
+// LoadConfig loads configuration from the specified path
+func LoadConfig(path string) (*Config, error) {
+	// Load default configuration
+	cfg := DefaultConfig()
+
+	// Check if file exists
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		return cfg, fmt.Errorf("config file not found: %s", path)
+	}
+
+	// Read file
+	configFile, err := os.ReadFile(path)
+	if err != nil {
+		return cfg, fmt.Errorf("error reading config file: %v", err)
+	}
+
+	// Parse JSON
+	if err := json.Unmarshal(configFile, cfg); err != nil {
+		return cfg, fmt.Errorf("error parsing config file: %v", err)
+	}
+
+	return cfg, nil
+}
+
+// SaveConfig saves configuration to a file
+func SaveConfig(cfg *Config, path string) error {
+	// Convert to JSON
+	configJSON, err := json.MarshalIndent(cfg, "", "  ")
+	if err != nil {
+		return fmt.Errorf("error encoding config to JSON: %v", err)
+	}
+
+	// Write to file
+	if err := os.WriteFile(path, configJSON, 0644); err != nil {
+		return fmt.Errorf("error writing config file: %v", err)
+	}
+
+	return nil
+}

examples/sip_client.go

@@ -0,0 +1,166 @@
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"time"
+)
+
+// Sample SIP client
+func main() {
+	// Parse command line arguments
+	serverAddr := flag.String("server", "127.0.0.1:5060", "SIP server address")
+	username := flag.String("user", "user1", "SIP username")
+	flag.Parse()
+
+	// Establish UDP connection
+	addr, err := net.ResolveUDPAddr("udp", *serverAddr)
+	if err != nil {
+		log.Fatalf("Address resolution error: %v", err)
+	}
+
+	conn, err := net.DialUDP("udp", nil, addr)
+	if err != nil {
+		log.Fatalf("UDP connection error: %v", err)
+	}
+	defer conn.Close()
+
+	fmt.Printf("SIP client started: %s\n", *username)
+	fmt.Println("Commands: register, invite, bye, exit")
+
+	// Goroutine for receiving responses
+	go func() {
+		buffer := make([]byte, 65535)
+		for {
+			n, _, err := conn.ReadFromUDP(buffer)
+			if err != nil {
+				log.Printf("Response reading error: %v", err)
+				continue
+			}
+			fmt.Printf("\nReceived response:\n%s\n", string(buffer[:n]))
+		}
+	}()
+
+	// Command input loop
+	scanner := bufio.NewScanner(os.Stdin)
+	for {
+		fmt.Print("> ")
+		if !scanner.Scan() {
+			break
+		}
+
+		cmd := scanner.Text()
+		if cmd == "exit" {
+			break
+		}
+
+		switch cmd {
+		case "register":
+			sendRegister(conn, *username)
+		case "invite":
+			fmt.Print("Username to call: ")
+			if !scanner.Scan() {
+				break
+			}
+			callee := scanner.Text()
+			sendInvite(conn, *username, callee)
+		case "bye":
+			sendBye(conn, *username)
+		default:
+			fmt.Println("Unknown command. Enter register, invite, bye, or exit.")
+		}
+	}
+}
+
+func sendRegister(conn *net.UDPConn, username string) {
+	callID := generateCallID()
+
+	msg := fmt.Sprintf("REGISTER sip:%s@localhost SIP/2.0\r\n"+
+		"Via: SIP/2.0/UDP 127.0.0.1:5060;branch=z9hG4bK%s\r\n"+
+		"From: <sip:%s@localhost>;tag=%s\r\n"+
+		"To: <sip:%s@localhost>\r\n"+
+		"Call-ID: %s\r\n"+
+		"CSeq: 1 REGISTER\r\n"+
+		"Contact: <sip:%[email protected]>\r\n"+
+		"Max-Forwards: 70\r\n"+
+		"User-Agent: Go-SIP-Client\r\n"+
+		"Expires: 3600\r\n"+
+		"Content-Length: 0\r\n\r\n",
+		username, generateBranch(), username, generateTag(), username, callID, username)
+
+	_, err := conn.Write([]byte(msg))
+	if err != nil {
+		log.Printf("Message sending error: %v", err)
+		return
+	}
+
+	fmt.Println("REGISTER sent")
+}
+
+func sendInvite(conn *net.UDPConn, caller, callee string) {
+	callID := generateCallID()
+
+	sdp := fmt.Sprintf("v=0\r\n"+
+		"o=%s 123456 654321 IN IP4 127.0.0.1\r\n"+
+		"s=SIP Call\r\n"+
+		"c=IN IP4 127.0.0.1\r\n"+
+		"t=0 0\r\n"+
+		"m=audio 49170 RTP/AVP 0\r\n"+
+		"a=rtpmap:0 PCMU/8000\r\n", caller)
+
+	msg := fmt.Sprintf("INVITE sip:%s@localhost SIP/2.0\r\n"+
+		"Via: SIP/2.0/UDP 127.0.0.1:5060;branch=z9hG4bK%s\r\n"+
+		"From: <sip:%s@localhost>;tag=%s\r\n"+
+		"To: <sip:%s@localhost>\r\n"+
+		"Call-ID: %s\r\n"+
+		"CSeq: 1 INVITE\r\n"+
+		"Contact: <sip:%[email protected]>\r\n"+
+		"Content-Type: application/sdp\r\n"+
+		"Content-Length: %d\r\n\r\n%s",
+		callee, generateBranch(), caller, generateTag(), callee, callID, caller, len(sdp), sdp)
+
+	_, err := conn.Write([]byte(msg))
+	if err != nil {
+		log.Printf("Message sending error: %v", err)
+		return
+	}
+
+	fmt.Println("INVITE sent")
+}
+
+func sendBye(conn *net.UDPConn, username string) {
+	callID := generateCallID()
+
+	msg := fmt.Sprintf("BYE sip:server@localhost SIP/2.0\r\n"+
+		"Via: SIP/2.0/UDP 127.0.0.1:5060;branch=z9hG4bK%s\r\n"+
+		"From: <sip:%s@localhost>;tag=%s\r\n"+
+		"To: <sip:server@localhost>;tag=as6f4bc61\r\n"+
+		"Call-ID: %s\r\n"+
+		"CSeq: 1 BYE\r\n"+
+		"Content-Length: 0\r\n\r\n",
+		generateBranch(), username, generateTag(), callID)
+
+	_, err := conn.Write([]byte(msg))
+	if err != nil {
+		log.Printf("Message sending error: %v", err)
+		return
+	}
+
+	fmt.Println("BYE sent")
+}
+
+func generateCallID() string {
+	return fmt.Sprintf("%d", time.Now().UnixNano())
+}
+
+func generateTag() string {
+	return fmt.Sprintf("%d", time.Now().UnixNano()%100000)
+}
+
+func generateBranch() string {
+	return fmt.Sprintf("%d", time.Now().UnixNano()%1000000)
+}

go.mod

@@ -0,0 +1,3 @@
+module github.com/user/go-sip
+
+go 1.20