Use raw TCP instead of HTTP to transfer files

config.go

@@ -8,6 +8,7 @@ import (
 	"github.com/rs/zerolog/log"
 	"io"
 	"io/ioutil"
+	"net/url"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -25,6 +26,24 @@ func NewConfig(actionType string, actionData string) *Config {
 	return &Config{ActionType: actionType, ActionData: actionData}
 }
 
+func (config *Config) Validate()  {
+	// Parse URL in config
+	urlParser, err := url.Parse(config.ActionData)
+	// If there was an error parsing
+	if err != nil {
+		// Alert user of invalid url
+		log.Fatal().Err(err).Msg("Invalid URL")
+	// If scheme is not detected
+	} else if urlParser.Scheme == "" {
+		// Alert user of invalid scheme
+		log.Fatal().Msg("Invalid URL scheme")
+	// If host is not detected
+	} else if urlParser.Host == "" {
+		// Alert user of invalid host
+		log.Fatal().Msg("Invalid URL host")
+	}
+}
+
 // Create config file
 func (config *Config) CreateFile(dir string) {
 	// Use ConsoleWriter logger
@@ -137,8 +156,23 @@ func (config *Config) ExecuteAction(srcDir string, destDir string) {
 		if err != nil { log.Fatal().Err(err).Msg("Error copying data to file") }
 	// If action is url
 	} else if config.ActionType == "url" {
+		// Parse received URL
+		urlParser, err := url.Parse(config.ActionData)
+		// If there was an error parsing
+		if err != nil {
+			// Alert user of invalid url
+			log.Fatal().Err(err).Msg("Invalid URL")
+		// If scheme is not detected
+		} else if urlParser.Scheme == "" {
+			// Alert user of invalid scheme
+			log.Fatal().Msg("Invalid URL scheme")
+		// If host is not detected
+		} else if urlParser.Host == "" {
+			// Alert user of invalid host
+			log.Fatal().Msg("Invalid URL host")
+		}
 		// Attempt to open URL in browser
-		err := browser.OpenURL(config.ActionData)
+		err = browser.OpenURL(config.ActionData)
 		if err != nil { log.Fatal().Err(err).Msg("Error opening browser") }
 	// If action is dir
 	} else if config.ActionType == "dir" {

files.go

@@ -1,19 +1,20 @@
 package main
 
 import (
-	"context"
+	"bufio"
+	"bytes"
+	"encoding/hex"
+	"errors"
 	"fmt"
 	"github.com/rs/zerolog"
 	"github.com/rs/zerolog/log"
 	"io"
 	"io/ioutil"
 	"net"
-	"net/http"
 	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
-	"time"
 )
 
 // Save encrypted key to file
@@ -34,147 +35,179 @@ func SaveEncryptedKey(encryptedKey []byte, filePath string) {
 
 // Create HTTP server to transmit files
 func SendFiles(dir string) {
-	// Use ConsoleWriter logger
+	// Use ConsoleWriter logger with normal FatalHook
 	log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr}).Hook(FatalHook{})
-	// Instantiate http.Server struct
-	srv := &http.Server{}
-	// Listen on all ipv4 addresses on port 9898
+	// Create TCP listener on port 9898
 	listener, err := net.Listen("tcp", ":9898")
 	if err != nil { log.Fatal().Err(err).Msg("Error starting listener") }
-
-	// If client connects to /:filePath
-	http.HandleFunc("/", func(res http.ResponseWriter, req *http.Request) {
-		// Set file to first path components of URL, excluding first /
-		file := req.URL.Path[1:]
-		// Read file at specified location
-		fileData, err := ioutil.ReadFile(dir + "/" + file)
-		// If there was an error reading
-		if err != nil {
-			// Warn user of error
-			log.Warn().Err(err).Msg("Error reading file")
-		// Otherwise
-		} else {
-			// Inform user client has requested a file
-			log.Info().Str("file", file).Msg("GET File")
-		}
-		// Write file to ResponseWriter
-		_, err = fmt.Fprint(res, string(fileData))
-		if err != nil { log.Fatal().Err(err).Msg("Error writing response") }
-	})
-
-	// If client connects to /index
-	http.HandleFunc("/index", func(res http.ResponseWriter, req *http.Request) {
-		// Inform user a client has requested the file index
-		log.Info().Msg("GET Index")
-		// Get directory listing
-		dirListing, err := ioutil.ReadDir(dir)
-		if err != nil { log.Fatal().Err(err).Msg("Error reading directory") }
-		// Create new slice to house filenames for index
-		var indexSlice []string
-		// For each file in listing
-		for _, file := range dirListing {
-			// If the file is not the key
-			if !strings.Contains(file.Name(), "key.aes") {
-				// Append the file path to indexSlice
-				indexSlice = append(indexSlice, file.Name())
+	// Accept connection on listener
+	connection, err := listener.Accept()
+	if err != nil { log.Fatal().Err(err).Msg("Error accepting connection") }
+	// Close connection at the end of this function
+	defer connection.Close()
+	// Create for loop to listen for messages on connection
+	connectionLoop: for {
+		// Use ConsoleWriter logger with TCPFatalHook
+		log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr}).Hook(TCPFatalHook{conn: connection})
+		// Attempt to read new message on connection
+		data, err := bufio.NewReader(connection).ReadString('\n')
+		// If no message detected, try again
+		if err != nil && err.Error() == "EOF" { continue }
+		// If non-EOF error, fatally log
+		if err != nil { log.Fatal().Err(err).Msg("Error reading data") }
+		// Process received data
+		processedData := strings.Split(strings.TrimSpace(data), ";")
+		// If processedData is empty, alert the user of invalid data
+		if len(processedData) < 1 { log.Fatal().Str("data", data).Msg("Received data invalid") }
+		switch processedData[0] {
+		case "key":
+			// Inform user client has requested key
+			log.Info().Msg("Key requested")
+			// Read saved key
+			key, err := ioutil.ReadFile(dir + "/key.aes")
+			if err != nil { log.Fatal().Err(err).Msg("Error reading key") }
+			// Write saved key to ResponseWriter
+			_, err = fmt.Fprintln(connection, "OK;" + hex.EncodeToString(key) + ";")
+			if err != nil { log.Fatal().Err(err).Msg("Error writing response") }
+		case "index":
+			// Inform user a client has requested the file index
+			log.Info().Msg("Index requested")
+			// Get directory listing
+			dirListing, err := ioutil.ReadDir(dir)
+			if err != nil { log.Fatal().Err(err).Msg("Error reading directory") }
+			// Create new slice to house filenames for index
+			var indexSlice []string
+			// For each file in listing
+			for _, file := range dirListing {
+				// If the file is not the key
+				if !strings.Contains(file.Name(), "key.aes") {
+					// Append the file path to indexSlice
+					indexSlice = append(indexSlice, file.Name())
+				}
 			}
+			// Join index slice into string
+			indexStr := strings.Join(indexSlice, "|")
+			// Write index to ResponseWriter
+			_, err = fmt.Fprintln(connection, "OK;" + indexStr + ";")
+			if err != nil { log.Fatal().Err(err).Msg("Error writing response") }
+		case "file":
+			// If processedData only has one entry
+			if len(processedData) == 1 {
+				// Warn user of unexpected end of line
+				log.Warn().Err(errors.New("unexpected eol")).Msg("Invalid file request")
+				// Send error to connection
+				_, _ = fmt.Fprintln(connection, "ERR;")
+				// Break out of switch
+				break
+			}
+			// Set file to first path components of URL, excluding first /
+			file := processedData[1]
+			// Read file at specified location
+			fileData, err := ioutil.ReadFile(dir + "/" + file)
+			// If there was an error reading
+			if err != nil {
+				// Warn user of error
+				log.Warn().Err(err).Msg("Error reading file")
+				// Otherwise
+			} else {
+				// Inform user client has requested a file
+				log.Info().Str("file", file).Msg("File requested")
+			}
+			// Write file as hex to connection
+			_, err = fmt.Fprintln(connection, "OK;" + hex.EncodeToString(fileData) + ";")
+			if err != nil { log.Fatal().Err(err).Msg("Error writing response") }
+		case "stop":
+			// Alert user that stop signal has been received
+			log.Info().Msg("Received stop signal")
+			// Print ok message to connection
+			_, _ = fmt.Fprintln(connection, "OK;")
+			// Break out of connectionLoop
+			break connectionLoop
 		}
-		// Join index slice into string
-		indexStr := strings.Join(indexSlice, ";")
-		// Write index to ResponseWriter
-		_, err = fmt.Fprint(res, indexStr)
-		if err != nil { log.Fatal().Err(err).Msg("Error writing response") }
-	})
+	}
+}
 
-	// If client connects to /key
-	http.HandleFunc("/key", func(res http.ResponseWriter, req *http.Request) {
-		// Inform user a client has requested the key
-		log.Info().Msg("GET Key")
-		// Read saved key
-		key, err := ioutil.ReadFile(dir + "/key.aes")
-		if err != nil { log.Fatal().Err(err).Msg("Error reading key") }
-		// Write saved key to ResponseWriter
-		_, err = fmt.Fprint(res, string(key))
-		if err != nil { log.Fatal().Err(err).Msg("Error writing response") }
-	})
-
-	// If client connects to /stop
-	http.HandleFunc("/stop", func(res http.ResponseWriter, req *http.Request) {
-		// Inform user a client has requested server shutdown
-		log.Info().Msg("GET Stop")
-		log.Info().Msg("Stop signal received")
-		// Shutdown server and send to empty context
-		err := srv.Shutdown(context.Background())
-		if err != nil { log.Fatal().Err(err).Msg("Error stopping server") }
-	})
-
-	// Start HTTP Server
-	_ = srv.Serve(listener)
+func ConnectToSender(senderAddr string) net.Conn {
+	// Get server address by getting the IP without the port, and appending :9898
+	serverAddr := strings.Split(senderAddr, ":")[0] + ":9898"
+	// Create error variable
+	var err error
+	// Create connection variable
+	var connection net.Conn
+	// Until break
+	for {
+		// Try connecting to sender
+		connection, err = net.Dial("tcp", serverAddr)
+		// If connection refused
+		if err != nil && strings.Contains(err.Error(), "connection refused") {
+			// Continue loop (retry)
+			continue
+			// If error other than connection refused
+		} else if err != nil {
+			// Fatally log
+			log.Fatal().Err(err).Msg("Error connecting to sender")
+			// If no error
+		} else {
+			// Break out of loop
+			break
+		}
+	}
+	// Returned created connection
+	return connection
 }
 
 // Get files from sender
-func RecvFiles(senderAddr string) {
+func RecvFiles(connection net.Conn) {
 	// Use ConsoleWriter logger
 	log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr}).Hook(FatalHook{})
-	// Get server address by getting the IP without the port, prepending http:// and appending :9898
-	serverAddr := "http://" + strings.Split(senderAddr, ":")[0] + ":9898"
-	var response *http.Response
-	// GET /index on sender's HTTP server
-	response, err := http.Get(serverAddr + "/index")
-	// If error occurred, retry every 500ms
-	if err != nil {
-		// Set index failed to true
-		indexGetFailed := true
-		for indexGetFailed {
-			// GET /index on sender's HTTP server
-			response, err = http.Get(serverAddr + "/index")
-			// If no error, set index failed to false
-			if err == nil { indexGetFailed = false }
-			// Wait 500ms
-			time.Sleep(500*time.Millisecond)
-		}
-	}
-	// Close response body at the end of this function
-	defer response.Body.Close()
-	// Create index slice for storage of file index
-	var index []string
-	// If server responded with 200 OK
-	if response.StatusCode == http.StatusOK {
-		// Read response body
-		body, err := ioutil.ReadAll(response.Body)
-		if err != nil { log.Fatal().Err(err).Msg("Error reading HTTP response") }
-		// Get string from body
-		bodyStr := string(body)
-		// Split string to form index
-		index = strings.Split(bodyStr, ";")
-	}
-	// For each file in the index
+	// Request index from sender
+	_, err := fmt.Fprintln(connection, "index;")
+	if err != nil { log.Fatal().Err(err).Msg("Error sending index request") }
+	// Read received message
+	message, err := bufio.NewReader(connection).ReadString('\n')
+	if err != nil { log.Fatal().Err(err).Msg("Error getting index") }
+	// Process received message
+	procMessage := strings.Split(strings.TrimSpace(message), ";")
+	// If non-ok code returned, fatally log
+	if procMessage[0] != "OK" { log.Fatal().Err(err).Msg("Sender reported error") }
+	// Get index from message
+	index := strings.Split(strings.TrimSpace(procMessage[1]), "|")
 	for _, file := range index {
-		// GET current file in index
-		response, err := http.Get(serverAddr + "/" + filepath.Base(file))
+		// Get current file in index
+		_, err = fmt.Fprintln(connection, "file;" + file + ";")
+		if err != nil { log.Fatal().Err(err).Msg("Error sending file request") }
+		// Read received message
+		message, err := bufio.NewReader(connection).ReadString('\n')
 		if err != nil { log.Fatal().Err(err).Msg("Error getting file") }
-		// If server responded with 200 OK
-		if response.StatusCode == http.StatusOK {
+		// Process received message
+		procMessage := strings.Split(message, ";")
+		// If non-ok code returned
+		if procMessage[0] != "OK" {
+			// fatally log
+			log.Fatal().Err(err).Msg("Sender reported error")
+		// Otherwise
+		} else {
 			// Create new file at index filepath
 			newFile, err := os.Create(opensendDir + "/" + file)
 			if err != nil { log.Fatal().Err(err).Msg("Error creating file") }
+			// Decode file data from hex string
+			fileData, err := hex.DecodeString(strings.TrimSpace(procMessage[1]))
+			if err != nil { log.Fatal().Err(err).Msg("Error decoding hex") }
 			// Copy response body to new file
-			bytesWritten, err := io.Copy(newFile, response.Body)
+			bytesWritten, err := io.Copy(newFile, bytes.NewBuffer(fileData))
 			if err != nil { log.Fatal().Err(err).Msg("Error writing to file") }
 			// Log bytes written
 			log.Info().Str("file", filepath.Base(file)).Msg("Wrote " + strconv.Itoa(int(bytesWritten)) + " bytes")
 			// Close new file
 			newFile.Close()
 		}
-		// Close response body
-		response.Body.Close()
 	}
 }
 
-// Send stop signal to sender's HTTP server
-func SendSrvStopSignal(senderAddr string) {
-	// Get server address by getting the IP without the port, prepending http:// and appending :9898
-	serverAddr := "http://" + strings.Split(senderAddr, ":")[0] + ":9898"
-	// GET /stop on sender's HTTP servers ignoring any errors
-	_, _ = http.Get(serverAddr + "/stop")
+// Send stop signal to sender
+func SendSrvStopSignal(connection net.Conn) {
+	// Send stop signal to connection
+	_, _ = fmt.Fprintln(connection, "stop;")
+	// Close connection
+	_ = connection.Close()
 }

keyCrypto.go

@@ -1,13 +1,15 @@
 package main
 
 import (
+	"bufio"
 	"crypto/rand"
 	"crypto/rsa"
 	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
 	"github.com/rs/zerolog"
 	"github.com/rs/zerolog/log"
-	"io/ioutil"
-	"net/http"
+	"net"
 	"os"
 	"strings"
 )
@@ -26,27 +28,28 @@ func GenerateRSAKeypair() (*rsa.PrivateKey, *rsa.PublicKey) {
 }
 
 // Get public key from sender
-func GetKey(senderAddr string) []byte {
+func GetKey(connection net.Conn) []byte {
 	// Use ConsoleWriter logger
 	log.Logger = log.Output(zerolog.ConsoleWriter{Out: os.Stderr}).Hook(FatalHook{})
-	// Get server address by getting the IP without the port, prepending http:// and appending :9898
-	serverAddr := "http://" + strings.Split(senderAddr, ":")[0] + ":9898"
-	// GET /key on the sender's HTTP server
-	response, err := http.Get(serverAddr + "/key")
+	// Send key request to connection
+	_, err := fmt.Fprintln(connection, "key;")
+	if err != nil { log.Fatal().Err(err).Msg("Error sending key request") }
+	// Read received message
+	message, err := bufio.NewReader(connection).ReadString('\n')
 	if err != nil { log.Fatal().Err(err).Msg("Error getting key") }
-	// Close response body at the end of this function
-	defer response.Body.Close()
-	// If server responded with 200 OK
-	if response.StatusCode == http.StatusOK {
-		// Read response body into key
-		key, err := ioutil.ReadAll(response.Body)
-		if err != nil { log.Fatal().Err(err).Msg("Error reading HTTP response") }
+	// Process received message
+	procMessage := strings.Split(strings.TrimSpace(message), ";")
+	// If ok code returned
+	if procMessage[0] == "OK" {
+		// Decode received hex string into key
+		key, err := hex.DecodeString(procMessage[1])
+		if err != nil { log.Fatal().Err(err).Msg("Error reading key") }
 		// Return key
 		return key
 	// Otherwise
 	} else {
-		// Fatally log status code
-		if err != nil { log.Fatal().Int("code", response.StatusCode).Msg("HTTP Error Response Code Received") }
+		// Fatally log
+		if err != nil { log.Fatal().Msg("Server reported error") }
 	}
 	// Return nil if all else fails
 	return nil

logging.go

@@ -1,12 +1,16 @@
 package main
 
 import (
+	"fmt"
 	"github.com/rs/zerolog"
+	"net"
 	"os"
 )
 
+// Fatal hook to run in case of Fatal error
 type FatalHook struct {}
 
+// Run function on trigger
 func (hook FatalHook) Run(_ *zerolog.Event, level zerolog.Level, _ string) {
 	// If log event is fatal
 	if level == zerolog.FatalLevel {
@@ -14,3 +18,22 @@ func (hook FatalHook) Run(_ *zerolog.Event, level zerolog.Level, _ string) {
 		_ = os.RemoveAll(opensendDir)
 	}
 }
+
+// TCP Fatal hook to run in case of Fatal error with open TCP connection
+type TCPFatalHook struct {
+	conn net.Conn
+}
+
+// Run function on trigger
+func (hook TCPFatalHook) Run(_ *zerolog.Event, level zerolog.Level, _ string) {
+	// If log event is fatal
+	if level == zerolog.FatalLevel {
+		// Send error to connection
+		_, _ = fmt.Fprintln(hook.conn, "ERR;")
+		// Close connection
+		_ = hook.conn.Close()
+		// Attempt removal of opensend directory
+		_ = os.RemoveAll(opensendDir)
+	}
+
+}

main.go

@@ -112,6 +112,14 @@ func main() {
 			// Get IP of chosen receiver
 			choiceIP = discoveredIPs[choiceIndex]
 		}
+		// Instantiate Config object
+		config := NewConfig(*actionType, *actionData)
+		// Validate data in config struct
+		config.Validate()
+		// Collect any files that may be required for transaction into opensend directory
+		config.CollectFiles(opensendDir)
+		// Create config file in opensend directory
+		config.CreateFile(opensendDir)
 		// Notify user of key exchange
 		log.Info().Msg("Performing key exchange")
 		// Exchange RSA keys with receiver
@@ -122,12 +130,6 @@ func main() {
 		key := EncryptKey(sharedKey, rawKey)
 		// Save encrypted key in opensend directory as key.aes
 		SaveEncryptedKey(key, opensendDir + "/key.aes")
-		// Instantiate Config object
-		config := NewConfig(*actionType, *actionData)
-		// Collect any files that may be required for transaction into opensend directory
-		config.CollectFiles(opensendDir)
-		// Create config file in opensend directory
-		config.CreateFile(opensendDir)
 		// Notify user file encryption is beginning
 		log.Info().Msg("Encrypting files")
 		// Encrypt all files in opensend directory using shared key
@@ -157,12 +159,14 @@ func main() {
 		time.Sleep(300*time.Millisecond)
 		// Notify user files are being received
 		log.Info().Msg("Receiving files from server (This may take a while)")
+		// Connect to sender's TCP socket
+		connection := ConnectToSender(senderIP)
 		// Get files from sender and place them into the opensend directory
-		RecvFiles(senderIP)
+		RecvFiles(connection)
 		// Get encrypted shared key from sender
-		encryptedKey := GetKey(senderIP)
+		encryptedKey := GetKey(connection)
 		// Send stop signal to sender's HTTP server
-		SendSrvStopSignal(senderIP)
+		SendSrvStopSignal(connection)
 		// Decrypt shared key
 		sharedKey := DecryptKey(encryptedKey, privateKey)
 		// Notify user file decryption is beginning