Removed old email from license notices; minor changes to the program output, help message

README.md

@@ -16,7 +16,7 @@ In order to transfer one file on one computer to another - they need to establis
 
 In order to establish a connection - there needs to be a 1) sender (server) (the owner of the file), waiting for connections, and a 2) receiver (client), who will try to connect to a sender (server). If the requirements are met - client will connect to server and the packet exchange will begin.
  
-The server and the client needs to communicate with packets according to certain rules, given by a [protocol](https://github.com/Unbewohnte/ftu/tree/main/src/protocol).
+The server and the client needs to communicate with packets according to certain rules, given by a [protocol](http://unbewohnte.xyz:3000/Unbewohnte/ftu/src/branch/main/src/protocol).
 
 The packet has its header and body. They are divided into several groups of use by headers, this way we can specify what kind of data is stored inside packet`s body and react accordingly.
 
@@ -28,13 +28,13 @@ Thus, with a connection and a way of communication, the sender will send some pa
 ## ● Installation
 
 ### ● From release (Pre-compiled)
-- Proceed to [releases page](https://github.com/Unbewohnte/ftu/releases)
+- Proceed to [releases page](http://unbewohnte.xyz:3000/Unbewohnte/ftu/releases)
 - Choose a version/architecture you have and download an archive
 - Unpack an archive
 - If on GNU/Linux - run `chmod +x install.sh && sudo ./install.sh`
 
 ### ● From source (Compile it yourself) (You need [Go](https://golang.org/dl/) and [git](https://git-scm.com/) to be installed on your machine)
-- `git clone https://github.com/Unbewohnte/ftu.git`
+- `git clone http://unbewohnte.xyz:3000/Unbewohnte/ftu`
 - `cd` into the folder
 - If on GNU/Linux - run `make && sudo make install` or `make && chmod +x install.sh && sudo ./install`
 - else - cd into src/ folder and simply run `go build`; after that you`re free to put the binary wherever you desire 
@@ -46,7 +46,7 @@ Now you have ftu installed !
 ## ● Usage
 `ftu -h` - to print a usage message
 
-`ftu [FLAGS]`
+`ftu [FLAGs]`
 
 ### ● FLAGs
 - -p [uint] for port
@@ -81,10 +81,6 @@ creates a node that will send every file in the directory !RECUSRIVELY!
 
 `make test` or in "src" directory `go test ./...`
 
----
-
-## ● Inspired by [croc](https://github.com/schollz/croc)
-
 --- 
 
 ## ● License

src/addr/local.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 

src/checksum/checksum.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 
@@ -21,6 +21,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 package checksum
 
 import (
+	"bytes"
 	"crypto/sha256"
 	"encoding/hex"
 	"io"
@@ -36,8 +37,8 @@ import (
 // GetPartialCheckSum is default method used to get a file checksum by sender and receiver
 func GetPartialCheckSum(file *os.File) (string, error) {
 	// "capturing" CHUNKSIZE bytes and then skipping STEP bytes before the next chunk until the last one
-	const CHUNKS uint = 100
+	const CHUNKS uint = 50
-	const CHUNKSIZE uint = 100
+	const CHUNKSIZE uint = 50
 	const STEP uint = 250
 
 	fileStats, err := file.Stat()
@@ -48,7 +49,7 @@ func GetPartialCheckSum(file *os.File) (string, error) {
 	fileSize := fileStats.Size()
 
 	if fileSize < int64(CHUNKS*CHUNKSIZE+STEP*(CHUNKS-1)) {
-		// file is too small to chop it in chunks, so just doing full checksum
+		// file is too small to chop it in chunks, so just get the full checksum
 
 		checksum, err := getFullCheckSum(file)
 		if err != nil {
@@ -62,19 +63,20 @@ func GetPartialCheckSum(file *os.File) (string, error) {
 		return "", err
 	}
 
-	var capturedChunks string
+	// var capturedChunks string
+	var capturedChunks bytes.Buffer
 	var read uint64 = 0
 	for i := 0; uint(i) < CHUNKS; i++ {
 		buffer := make([]byte, CHUNKSIZE)
 		r, _ := file.ReadAt(buffer, int64(read))
 
-		capturedChunks += string(buffer)
+		capturedChunks.Write(buffer)
 
 		read += uint64(r)
 		read += uint64(STEP)
 	}
 
-	checksumBytes := sha256.Sum256([]byte(capturedChunks))
+	checksumBytes := sha256.Sum256(capturedChunks.Bytes())
 	checksum := hex.EncodeToString(checksumBytes[:])
 
 	return checksum, nil

src/checksum/checksum_test.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 

src/encryption/decrypt.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 

src/encryption/encrypt.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 

src/encryption/encryption_test.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 

src/encryption/key.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 

src/fsys/dir.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 
@@ -22,6 +22,7 @@ package fsys
 
 import (
 	"fmt"
+	"io/fs"
 	"os"
 	"path/filepath"
 )
@@ -32,6 +33,7 @@ type Directory struct {
 	Path               string
 	Size               uint64
 	RelativeParentPath string // Relative path to the directory, where the highest point in the hierarchy is the upmost parent dir. Set manually
+	Symlinks           []*Symlink
 	Files              []*File
 	Directories        []*Directory
 }
@@ -63,12 +65,13 @@ func GetDir(path string, recursive bool) (*Directory, error) {
 
 	// loop through each entry in the directory
 	entries, err := os.ReadDir(absPath)
-	if err != nil {
+	if err != nil && err != fs.ErrPermission {
 		return nil, err
 	}
 
 	var innerDirs []*Directory
 	var innerFiles []*File
+	var innerSymlinks []*Symlink
 	for _, entry := range entries {
 		entryInfo, err := entry.Info()
 		if err != nil {
@@ -92,21 +95,42 @@ func GetDir(path string, recursive bool) (*Directory, error) {
 			// if not - skip the directory and only work with the files
 
 		} else {
-			innerFilePath := filepath.Join(absPath, entryInfo.Name())
+			// not a directory
 
-			innerFile, err := GetFile(innerFilePath)
+			switch entryInfo.Mode()&os.ModeSymlink != 0 {
-			if err != nil {
+			case true:
-				return nil, err
+				// it is a symlink
-			}
+				innerSymlinkPath := filepath.Join(absPath, entryInfo.Name())
+
+				symlink, err := GetSymlink(innerSymlinkPath, false)
+				if err != nil {
+					// skip this symlink
+					continue
+				}
 
-			directory.Size += innerFile.Size
+				innerSymlinks = append(innerSymlinks, symlink)
 
-			innerFiles = append(innerFiles, innerFile)
+			case false:
+				// it is a usual file
+
+				innerFilePath := filepath.Join(absPath, entryInfo.Name())
+
+				innerFile, err := GetFile(innerFilePath)
+				if err != nil {
+					// skip this file
+					continue
+				}
+
+				directory.Size += innerFile.Size
+
+				innerFiles = append(innerFiles, innerFile)
+			}
 		}
 	}
 
 	directory.Directories = innerDirs
 	directory.Files = innerFiles
+	directory.Symlinks = innerSymlinks
 
 	return &directory, nil
 }
@@ -132,7 +156,27 @@ func (dir *Directory) GetAllFiles(recursive bool) []*File {
 	return files
 }
 
-// Sets `RelativeParentPath` relative to the given base path.
+// Returns every symlink in that directory
+func (dir *Directory) GetAllSymlinks(recursive bool) []*Symlink {
+	var symlinks []*Symlink = dir.Symlinks
+
+	if recursive {
+		if len(dir.Directories) == 0 {
+			return symlinks
+		}
+
+		for _, innerDir := range dir.Directories {
+			innerSymlinks := innerDir.GetAllSymlinks(recursive)
+			symlinks = append(symlinks, innerSymlinks...)
+		}
+	} else {
+		symlinks = dir.Symlinks
+	}
+
+	return symlinks
+}
+
+// Sets `RelativeParentPath` relative to the given base path for files and `Path`, `TargetPath` for symlinks so the
 // file with such path:
 // /home/user/directory/somefile.txt
 // had a relative path like that:
@@ -148,5 +192,20 @@ func (dir *Directory) SetRelativePaths(base string, recursive bool) error {
 		file.RelativeParentPath = relPath
 
 	}
+
+	for _, symlink := range dir.GetAllSymlinks(recursive) {
+		symRelPath, err := filepath.Rel(base, symlink.Path)
+		if err != nil {
+			return err
+		}
+		symlink.Path = symRelPath
+
+		symRelTargetPath, err := filepath.Rel(base, symlink.TargetPath)
+		if err != nil {
+			return err
+		}
+		symlink.TargetPath = symRelTargetPath
+	}
+
 	return nil
 }

src/fsys/dir_test.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 
@@ -21,6 +21,8 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 package fsys
 
 import (
+	"os"
+	"path/filepath"
 	"testing"
 )
 
@@ -79,25 +81,23 @@ func Test_GetFiles(t *testing.T) {
 
 }
 
-// func Test_SetRelativePaths(t *testing.T) {
+func Test_GetSymlinks(t *testing.T) {
-// 	dirpath := "../testfiles/"
+	dirpath := "../testfiles/"
 
-// 	dir, err := GetDir(dirpath, true)
+	os.Symlink(filepath.Join(dirpath, "testfile.txt"), filepath.Join(dirpath, "testsymlink.txt"))
-// 	if err != nil {
+	os.Symlink(filepath.Join(dirpath, "testdir", "testfile2.txt"), filepath.Join(dirpath, "testdir", "testsymlink2.txt"))
-// 		t.Fatalf("%s", err)
-// 	}
 
-// 	absDirPath, err := filepath.Abs(dirpath)
+	dir, err := GetDir(dirpath, true)
-// 	if err != nil {
+	if err != nil {
-// 		t.Fatalf("%s", err)
+		t.Fatalf("%s", err)
-// 	}
+	}
 
-// 	err = dir.SetRelativePaths(absDirPath, true)
+	// recursive
-// 	if err != nil {
+	symlinks := dir.GetAllSymlinks(true)
-// 		t.Fatalf("%s", err)
+
-// 	}
+	symlinkCount := 2
 
-// 	for count, file := range dir.GetAllFiles(true) {
+	if len(symlinks) != symlinkCount {
-// 		t.Errorf("[%d] %v\n", count, file.RelativeParentPath)
+		t.Fatalf("expected to get %d symlinks; got %d\n", symlinkCount, len(symlinks))
-// 	}
+	}
-// }
+}

src/fsys/file.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 
@@ -25,7 +25,7 @@ import (
 	"os"
 	"path/filepath"
 
-	"github.com/Unbewohnte/ftu/checksum"
+	"unbewohnte/ftu/checksum"
 )
 
 // A struct that represents the necessary file information for transportation through node
@@ -45,7 +45,7 @@ var ErrorNotFile error = fmt.Errorf("not a file")
 // Get general information about a file with the
 // future ability to open it.
 // NOTE that Handler field is nil BY DEFAULT until you
-// manually call a (file *File) Open() function to open it !
+// manually call (file *File).Open() to open it !
 func GetFile(path string) (*File, error) {
 	absPath, err := filepath.Abs(path)
 	if err != nil {

src/fsys/file_test.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 

src/fsys/symlink.go

@@ -0,0 +1,70 @@
+/*
+ftu - file transferring utility.
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
+
+This file is a part of ftu
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+package fsys
+
+import (
+	"fmt"
+	"os"
+)
+
+type Symlink struct {
+	TargetPath string
+	Path       string
+}
+
+// Checks whether path is referring to a symlink or not
+func IsSymlink(path string) (bool, error) {
+	stats, err := os.Lstat(path)
+	if err != nil {
+		return false, err
+	}
+	isSymlink := stats.Mode()&os.ModeSymlink != 0
+
+	return isSymlink, nil
+}
+
+var ErrorNotSymlink error = fmt.Errorf("not a symlink")
+
+// get necessary information about a symlink in a filesystem. If check is false -
+// does not check if path REALLY refers to a symlink
+func GetSymlink(path string, check bool) (*Symlink, error) {
+	if check {
+		isSymlink, err := IsSymlink(path)
+		if err != nil {
+			return nil, err
+		}
+		if !isSymlink {
+			return nil, ErrorNotSymlink
+		}
+	}
+
+	target, err := os.Readlink(path)
+	if err != nil {
+		return nil, err
+	}
+
+	symlink := Symlink{
+		TargetPath: target,
+		Path:       path,
+	}
+
+	return &symlink, nil
+}

src/fsys/symlink_test.go

@@ -0,0 +1,42 @@
+/*
+ftu - file transferring utility.
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
+
+This file is a part of ftu
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+package fsys
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func Test_IsSymlink(t *testing.T) {
+	dirpath := "../testfiles/"
+
+	symlinkPath := filepath.Join(dirpath, "testsymlink.txt")
+	os.Symlink(filepath.Join(dirpath, "testfile.txt"), symlinkPath)
+
+	isSymlink, err := IsSymlink(symlinkPath)
+	if err != nil {
+		t.Fatalf("%s\n", err)
+	}
+	if !isSymlink {
+		t.Fatalf("%s expected to be a symlink\n", symlinkPath)
+	}
+}

src/go.mod

@@ -1,3 +1,3 @@
-module github.com/Unbewohnte/ftu
+module unbewohnte/ftu
 
-go 1.17
+go 1.18

src/main.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte (https://unbewohnte.xyz/))
 
 This file is a part of ftu
 
@@ -26,13 +26,13 @@ import (
 	"fmt"
 	"os"
 
-	"github.com/Unbewohnte/ftu/node"
+	"unbewohnte/ftu/node"
 )
 
 var (
-	VERSION string = "v2.2.2"
+	VERSION string = "v2.3.3"
 
-	versionInformation string = fmt.Sprintf("ftu %s\n\nCopyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))\nThis program comes with ABSOLUTELY NO WARRANTY.\nThis is free software, and you are welcome to redistribute it under certain conditions; type \"ftu -l\" for details.\n", VERSION)
+	versionInformation string = fmt.Sprintf("ftu %s\nfile transferring utility\n\nCopyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)\nThis program comes with ABSOLUTELY NO WARRANTY.\nThis is free software, and you are welcome to redistribute it under certain conditions; type \"ftu -l\" for details.\n", VERSION)
 
 	//go:embed COPYING
 	licenseInformation string
@@ -52,15 +52,15 @@ var (
 
 func init() {
 	flag.Usage = func() {
-		fmt.Printf("ftu -[FLAG]...\n\n")
+		fmt.Printf("ftu -[FLAGs]\n\n")
 
 		fmt.Printf("[FLAGs]\n\n")
-		fmt.Printf("| -p [Uinteger_here] for port\n")
+		fmt.Printf("| -p [integer] for port\n")
-		fmt.Printf("| -r [true|false] for recursive sending of a directory\n")
+		fmt.Printf("| -r [true|false] send recursively or not\n")
 		fmt.Printf("| -a [ip_address|domain_name] address to connect to (cannot be used with -s)\n")
 		fmt.Printf("| -d [path_to_directory] where the files will be downloaded to (cannot be used with -s)\n")
-		fmt.Printf("| -s [path_to_file|directory] to send it (cannot be used with -a)\n")
+		fmt.Printf("| -s [path_to_file|directory] send it (cannot be used with -a)\n")
-		fmt.Printf("| -? [true|false] to turn on|off verbose output\n")
+		fmt.Printf("| -? [true|false] turn on|off verbose output\n")
 		fmt.Printf("| -l print license information\n")
 		fmt.Printf("| -v print version information\n\n\n")
 
@@ -98,12 +98,12 @@ func init() {
 
 	// validate flags
 	if *SEND == "" && *ADDRESS == "" {
-		fmt.Printf("Neither sending nor receiving flag was specified. Run ftu -h for help\n")
+		fmt.Printf("[ERROR] Neither sending nor receiving flag was specified. Run ftu -h for help\n")
 		os.Exit(-1)
 	}
 
 	if *SEND != "" && *ADDRESS != "" {
-		fmt.Printf("Can`t send and receive at the same time. Specify either -s or -a\n")
+		fmt.Printf("[ERROR] Can't send and receive at the same time. Specify either -s or -a\n")
 		os.Exit(-1)
 	}
 
@@ -122,11 +122,11 @@ func main() {
 		VerboseOutput: *VERBOSE,
 		IsSending:     isSending,
 		WorkingPort:   *PORT,
-		ServerSide: &node.ServerSideNodeOptions{
+		SenderSide: &node.SenderNodeOptions{
 			ServingPath: *SEND,
 			Recursive:   *RECUSRIVE,
 		},
-		ClientSide: &node.ClientSideNodeOptions{
+		ReceiverSide: &node.ReceiverNodeOptions{
 			ConnectionAddr:      *ADDRESS,
 			DownloadsFolderPath: *DOWNLOADS_DIR,
 		},
@@ -134,7 +134,7 @@ func main() {
 
 	node, err := node.NewNode(&nodeOptions)
 	if err != nil {
-		fmt.Printf("Error constructing a new node: %s\n", err)
+		fmt.Printf("[ERROR] Error constructing a new node: %s\n", err)
 		os.Exit(-1)
 	}
 

src/node/node.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 
@@ -32,11 +32,11 @@ import (
 
 	"fmt"
 
-	"github.com/Unbewohnte/ftu/addr"
+	"unbewohnte/ftu/addr"
-	"github.com/Unbewohnte/ftu/checksum"
+	"unbewohnte/ftu/checksum"
-	"github.com/Unbewohnte/ftu/encryption"
+	"unbewohnte/ftu/encryption"
-	"github.com/Unbewohnte/ftu/fsys"
+	"unbewohnte/ftu/fsys"
-	"github.com/Unbewohnte/ftu/protocol"
+	"unbewohnte/ftu/protocol"
 )
 
 // netInfowork specific settings
@@ -49,16 +49,18 @@ type netInfo struct {
 
 // Sending-side node information
 type sending struct {
-	ServingPath       string // path to the thing that will be sent
+	ServingPath         string // path to the thing that will be sent
-	IsDirectory       bool   // is ServingPath a directory
+	IsDirectory         bool   // is ServingPath a directory
-	Recursive         bool   // recursively send directory
+	Recursive           bool   // recursively send directory
-	CanSendBytes      bool   // is the other node ready to receive another piece
+	CanSendBytes        bool   // is the other node ready to receive another piece
-	AllowedToTransfer bool   // the way to notify the mainloop of a sending node to start sending pieces of files
+	AllowedToTransfer   bool   // the way to notify the mainloop of a sending node to start sending pieces of files
-	InTransfer        bool   // already transferring|receiving files
+	InTransfer          bool   // already transferring|receiving files
-	FilesToSend       []*fsys.File
+	FilesToSend         []*fsys.File
-	CurrentFileID     uint64 // an id of a file that is currently being transported
+	SymlinksToSend      []*fsys.Symlink
-	SentBytes         uint64 // how many bytes sent already
+	CurrentFileID       uint64 // an id of a file that is currently being transported
-	TotalTransferSize uint64 // how many bytes will be sent in total
+	SentBytes           uint64 // how many bytes sent already
+	TotalTransferSize   uint64 // how many bytes will be sent in total
+	CurrentSymlinkIndex uint64 // current index of a symlink that is
 }
 
 // Receiving-side node information
@@ -91,7 +93,7 @@ func NewNode(options *NodeOptions) (*Node, error) {
 	var isDir bool
 	if options.IsSending {
 		// sending node preparation
-		sendingPathStats, err := os.Stat(options.ServerSide.ServingPath)
+		sendingPathStats, err := os.Stat(options.SenderSide.ServingPath)
 		if err != nil {
 			return nil, err
 		}
@@ -106,12 +108,12 @@ func NewNode(options *NodeOptions) (*Node, error) {
 	} else {
 		// receiving node preparation
 		var err error
-		options.ClientSide.DownloadsFolderPath, err = filepath.Abs(options.ClientSide.DownloadsFolderPath)
+		options.ReceiverSide.DownloadsFolderPath, err = filepath.Abs(options.ReceiverSide.DownloadsFolderPath)
 		if err != nil {
 			return nil, err
 		}
 
-		err = os.MkdirAll(options.ClientSide.DownloadsFolderPath, os.ModePerm)
+		err = os.MkdirAll(options.ReceiverSide.DownloadsFolderPath, os.ModePerm)
 		if err != nil {
 			return nil, err
 		}
@@ -125,22 +127,22 @@ func NewNode(options *NodeOptions) (*Node, error) {
 		isSending:     options.IsSending,
 		netInfo: &netInfo{
 			Port:          options.WorkingPort,
-			ConnAddr:      options.ClientSide.ConnectionAddr,
+			ConnAddr:      options.ReceiverSide.ConnectionAddr,
 			EncryptionKey: nil,
 			Conn:          nil,
 		},
 		stopped: false,
 		transferInfo: &transferInfo{
 			Sending: &sending{
-				ServingPath:       options.ServerSide.ServingPath,
+				ServingPath:       options.SenderSide.ServingPath,
-				Recursive:         options.ServerSide.Recursive,
+				Recursive:         options.SenderSide.Recursive,
 				IsDirectory:       isDir,
 				TotalTransferSize: 0,
 				SentBytes:         0,
 			},
 			Receiving: &receiving{
 				AcceptedFiles:     nil,
-				DownloadsPath:     options.ClientSide.DownloadsFolderPath,
+				DownloadsPath:     options.ReceiverSide.DownloadsFolderPath,
 				ReceivedBytes:     0,
 				TotalDownloadSize: 0,
 			},
@@ -323,7 +325,7 @@ func (node *Node) send() {
 		incomingPacket, ok := <-node.packetPipe
 		if !ok {
 			fmt.Printf("\nThe connection has been closed unexpectedly\n")
-			os.Exit(-1.)
+			os.Exit(-1)
 		}
 
 		// if encryption key is set - decrypt packet on the spot
@@ -355,8 +357,10 @@ func (node *Node) send() {
 					panic(err)
 				}
 				filesToSend := DIRTOSEND.GetAllFiles(node.transferInfo.Sending.Recursive)
+				symlinksToSend := DIRTOSEND.GetAllSymlinks(node.transferInfo.Sending.Recursive)
+
+				node.transferInfo.Sending.SymlinksToSend = symlinksToSend
 
-				// notify the other node about all the files that are going to be sent
 				for counter, file := range filesToSend {
 					// assign ID and add it to the node sendlist
 					file.ID = uint64(counter)
@@ -410,7 +414,14 @@ func (node *Node) send() {
 
 		// Transfer section
 
-		if len(node.transferInfo.Sending.FilesToSend) == 0 {
+		// if all files have been sent -> send symlinks
+		if len(node.transferInfo.Sending.FilesToSend) == 0 && node.transferInfo.Sending.CurrentSymlinkIndex < uint64(len(node.transferInfo.Sending.SymlinksToSend)) {
+			protocol.SendSymlink(node.transferInfo.Sending.SymlinksToSend[node.transferInfo.Sending.CurrentSymlinkIndex], node.netInfo.Conn, encrKey)
+			node.transferInfo.Sending.CurrentSymlinkIndex++
+			continue
+		}
+
+		if len(node.transferInfo.Sending.FilesToSend) == 0 && node.transferInfo.Sending.CurrentSymlinkIndex == uint64(len(node.transferInfo.Sending.SymlinksToSend)) {
 			// if there`s nothing else to send - create and send DONE packet
 			protocol.SendPacket(node.netInfo.Conn, protocol.Packet{
 				Header: protocol.HeaderDone,
@@ -512,7 +523,7 @@ func (node *Node) send() {
 			default:
 				node.stopped = true
 
-				fmt.Printf("\nAn error occured while sending a piece of \"%s\": %s", node.transferInfo.Sending.FilesToSend[currentFileIndex].Name, err)
+				fmt.Printf("\n[ERROR] An error occured while sending a piece of \"%s\": %s", node.transferInfo.Sending.FilesToSend[currentFileIndex].Name, err)
 				panic(err)
 			}
 		}
@@ -525,7 +536,7 @@ func (node *Node) receive() {
 	// connect to the sending node
 	err := node.connect()
 	if err != nil {
-		fmt.Printf("\nCould not connect to %s:%d", node.netInfo.ConnAddr, node.netInfo.Port)
+		fmt.Printf("\n[ERROR] Could not connect to %s:%d\n", node.netInfo.ConnAddr, node.netInfo.Port)
 		os.Exit(-1)
 	}
 
@@ -763,10 +774,11 @@ func (node *Node) receive() {
 					// accepted
 
 					// append provided bytes to the file
-
+					if acceptedFile.Handler == nil {
-					err = acceptedFile.Open()
+						err = acceptedFile.Open()
-					if err != nil {
+						if err != nil {
-						panic(err)
+							panic(err)
+						}
 					}
 
 					fileBytes := fileBytesBuffer.Bytes()
@@ -777,11 +789,6 @@ func (node *Node) receive() {
 					}
 					acceptedFile.SentBytes += uint64(wrote)
 					node.transferInfo.Receiving.ReceivedBytes += uint64(wrote)
-
-					err = acceptedFile.Close()
-					if err != nil {
-						panic(err)
-					}
 				}
 			}
 
@@ -808,9 +815,11 @@ func (node *Node) receive() {
 						fmt.Printf("\n[File] fully received \"%s\" -- %d bytes", acceptedFile.Name, acceptedFile.Size)
 					}
 
-					err = acceptedFile.Open()
+					if acceptedFile.Handler == nil {
-					if err != nil {
+						err = acceptedFile.Open()
-						panic(err)
+						if err != nil {
+							panic(err)
+						}
 					}
 
 					// remove this file from the pool
@@ -823,7 +832,10 @@ func (node *Node) receive() {
 					}
 
 					if realChecksum != acceptedFile.Checksum {
-						fmt.Printf("\n| \"%s\" is corrupted", acceptedFile.Name)
+						if node.verboseOutput {
+							fmt.Printf("\n[ERROR] \"%s\" is corrupted", acceptedFile.Name)
+						}
+
 						acceptedFile.Close()
 						break
 					} else {
@@ -854,6 +866,41 @@ func (node *Node) receive() {
 
 			fmt.Printf("\nGot an encryption key: %s", encrKey)
 
+		case protocol.HeaderSymlink:
+			// SYMLINK~(string size in binary)(location in the filesystem)(string size in binary)(location of a target)
+			packetReader := bytes.NewReader(incomingPacket.Body)
+
+			// extract the location of the symlink
+			var locationSize uint64
+			binary.Read(packetReader, binary.BigEndian, &locationSize)
+
+			symlinkLocationBytes := make([]byte, locationSize)
+			packetReader.Read(symlinkLocationBytes)
+
+			// extract the target of a symlink
+			var targetSize uint64
+			binary.Read(packetReader, binary.BigEndian, &targetSize)
+
+			symlinkTargetLocationBytes := make([]byte, targetSize)
+			packetReader.Read(symlinkTargetLocationBytes)
+
+			symlinkLocation := string(symlinkLocationBytes)
+			symlinkTargetLocation := string(symlinkTargetLocationBytes)
+
+			// create a symlink
+
+			// should be already downloaded
+			symlinkDir := filepath.Join(node.transferInfo.Receiving.DownloadsPath, filepath.Dir(symlinkLocation))
+			os.MkdirAll(symlinkDir, os.ModePerm)
+
+			os.Symlink(
+				filepath.Join(node.transferInfo.Receiving.DownloadsPath, symlinkTargetLocation),
+				filepath.Join(node.transferInfo.Receiving.DownloadsPath, symlinkLocation))
+
+			protocol.SendPacket(node.netInfo.Conn, protocol.Packet{
+				Header: protocol.HeaderReady,
+			})
+
 		case protocol.HeaderDone:
 			node.mutex.Lock()
 			node.stopped = true

src/node/options.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 
@@ -20,12 +20,12 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 package node
 
-type ServerSideNodeOptions struct {
+type SenderNodeOptions struct {
 	ServingPath string
 	Recursive   bool
 }
 
-type ClientSideNodeOptions struct {
+type ReceiverNodeOptions struct {
 	ConnectionAddr      string
 	DownloadsFolderPath string
 }
@@ -35,6 +35,6 @@ type NodeOptions struct {
 	IsSending     bool
 	WorkingPort   uint
 	VerboseOutput bool
-	ServerSide    *ServerSideNodeOptions
+	SenderSide    *SenderNodeOptions
-	ClientSide    *ClientSideNodeOptions
+	ReceiverSide  *ReceiverNodeOptions
 }

src/protocol/constants.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 

src/protocol/headers.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 
@@ -114,3 +114,10 @@ const HeaderDirectory Header = "DIRECTORY"
 // Body must contain a file ID.
 // ie: ALREADYHAVE~(file ID in binary)
 const HeaderAlreadyHave Header = "ALREADYHAVE"
+
+// SYMLINK
+// Sent by sender AFTER ALL FILES has been sent already. Indicates that there
+// is a symlink in some place that points to some other already received file.
+// Body must contain information where the symlink is and the target file.
+// ie: SYMLINK~(string size in binary)(location in the filesystem)(string size in binary)(location of a target)
+const HeaderSymlink Header = "SYMLINK"

src/protocol/packet.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 
@@ -31,7 +31,7 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/Unbewohnte/ftu/encryption"
+	"unbewohnte/ftu/encryption"
 )
 
 // Internal representation of packet before|after the transportation

src/protocol/packetConstruct.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 
@@ -25,7 +25,7 @@ import (
 	"bytes"
 	"encoding/binary"
 
-	"github.com/Unbewohnte/ftu/fsys"
+	"unbewohnte/ftu/fsys"
 )
 
 // constructs a ready to send FILE packet

src/protocol/packetDecode.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 
@@ -26,7 +26,7 @@ import (
 	"encoding/binary"
 	"fmt"
 
-	"github.com/Unbewohnte/ftu/fsys"
+	"unbewohnte/ftu/fsys"
 )
 
 var ErrorWrongPacket error = fmt.Errorf("wrong type of packet header")

src/protocol/protocol_test.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 

src/protocol/recv.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 

src/protocol/send.go

@@ -1,6 +1,6 @@
 /*
 ftu - file transferring utility.
-Copyright (C) 2021,2022  Kasyanov Nikolay Alexeevich (Unbewohnte (https://unbewohnte.xyz/))
+Copyright (C) 2021,2022  Kasyanov Nikolay Alexeyevich (Unbewohnte)
 
 This file is a part of ftu
 
@@ -28,8 +28,8 @@ import (
 	"io"
 	"net"
 
-	"github.com/Unbewohnte/ftu/encryption"
+	"unbewohnte/ftu/encryption"
-	"github.com/Unbewohnte/ftu/fsys"
+	"unbewohnte/ftu/fsys"
 )
 
 // Sends given packet to connection.
@@ -174,7 +174,7 @@ func SendPiece(file *fsys.File, connection net.Conn, encrKey []byte) (uint64, er
 
 	if encrKey != nil {
 		// account for padding
-		canSendBytes -= 32
+		canSendBytes -= 48
 	}
 
 	if (file.Size - file.SentBytes) < canSendBytes {
@@ -209,3 +209,36 @@ func SendPiece(file *fsys.File, connection net.Conn, encrKey []byte) (uint64, er
 
 	return sentBytes, nil
 }
+
+// Sends a symlink to the other side. If encrKey is not nil - encrypts the packet with this key
+func SendSymlink(symlink *fsys.Symlink, connection net.Conn, encrKey []byte) error {
+	symlinkPacket := Packet{
+		Header: HeaderSymlink,
+	}
+
+	symlinkPacketBodyBuff := new(bytes.Buffer)
+
+	// SYMLINK~(string size in binary)(location in the filesystem)(string size in binary)(location of a target)
+
+	binary.Write(symlinkPacketBodyBuff, binary.BigEndian, uint64(len(symlink.Path)))
+	symlinkPacketBodyBuff.Write([]byte(symlink.Path))
+
+	binary.Write(symlinkPacketBodyBuff, binary.BigEndian, uint64(len(symlink.TargetPath)))
+	symlinkPacketBodyBuff.Write([]byte(symlink.TargetPath))
+
+	symlinkPacket.Body = symlinkPacketBodyBuff.Bytes()
+
+	if encrKey != nil {
+		err := symlinkPacket.EncryptBody(encrKey)
+		if err != nil {
+			return err
+		}
+	}
+
+	err := SendPacket(connection, symlinkPacket)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

src/testfiles/testdir/testsymlink2.txt

@@ -0,0 +1 @@
+../testfiles/testdir/testfile2.txt

src/testfiles/testsymlink.txt

@@ -0,0 +1 @@
+../testfiles/testfile.txt