[PD1] merge

Projs/PD1/README.md

@@ -1,6 +1,51 @@
-# Report
+# Relatório do Projeto de Desenvolvimento 1
+
+## Introdução 
+
+O nosso principal objetivo com este projeto foi consolidar os conceitos lecionados assim como simular interações com um cliente/entidade que nos "encomendou" o serviço, procurando satisfazer as necessidades e requisitos. O projeto consiste num sistema Cliente/Servidor, em que a aplicação cliente seria executada por cada utilizador que queria aceder ao serviço de mensagens, e o servidor seria responsável por responder aos pedidos dos utilizadores e armezenar de forma segura a informação. Para tal, o sistema deveria permitir a troca de mensagens entre os utilizadores, garantindo a autenticidade das mensagens.
+Algumas notas sobre o projeto:
+- Optamos por escolher **Golang** como linguagem visando uma implementação mais eficiente, robusta e segura ao nível de concorrência. 
+- Implementamos algumas funcionalidades extra, como o armazenamento dos dados no servidor numa base de dados **sqlite3** 
+Nas secções seguintes iremos detalhar cada componente do sistema, bem como as funcionalidades implementadas. 
+
+## Arquitetura do Sistema
+
+Neste projeto, a arquitetura do sistema é composta por 2 componentes principais:
+- **Cliente**: é a aplicação que cada utilizador executa para interagir com o servidor. O cliente é responsável por enviar mensagens para o servidor e receber mensagens de outros utilizadores (pelo servidor).
+- **Servidor**: é a aplicação que recebe os pedidos dos clientes, processa-os e responde de acordo. O servidor é responsável por armazenar as mensagens dos utilizadores e garantir a autenticidade das mensagens.
+
+### Crypto
+É importante destacar que, para garantir a segurança e integridade das mensagens, implementamos um protocolo de comunicação seguro. Este protocolo utiliza tanto criptografia simétrica quanto assimétrica. As mensagens são cifradas com a chave pública do destinatário para garantir a confidencialidade, enquanto são assinadas com a chave privada do emissor para autenticidade. Dessa forma, asseguramos que as mensagens sejam protegidas contra acessos não autorizados e que sua origem possa ser verificada.
+
+### Networking
+O canal de comunicação estabelecido entre o cliente e o servidor nesta implementação garante uma troca de dados segura e criptografada utilizando o protocolo TLS (Transport Layer Security). Ambos, cliente e servidor, empregam configurações TLS para cifrar os dados durante a transmissão, assegurando confidencialidade e integridade. Durante o handshake TLS, o servidor valida o certificado do cliente para verificar sua autenticidade, prevenindo acessos não autorizados. Este mecanismo robusto de segurança protege o canal de comunicação contra escutas, adulterações e ataques do tipo "man in the middle", garantindo uma troca de informações segura e confiável entre o cliente e o servidor.
+
+### Protocolo de Comunicação
+
+O package **protocol.go** define um conjunto de estruturas e funções que representam os diferentes tipos de pacotes que podem ser transmitidos entre o cliente e o servidor. Cada tipo de pacote é representado por uma constante PacketType, que indica a natureza da informação contida no pacote através de uma **flag**.
+
+As estruturas de dados definidas, como `GetUserCert`, `GetUnreadMsgsInfo`, `GetMsg`, `SendMsg`, `AnswerGetUserCert`, `AnswerGetUnreadMsgsInfo` e `AnswerGetMsg`, descrevem os formatos específicos de cada tipo de pacote a ser enviado e recebido. Cada estrutura contém os campos necessários para armazenar e representar os dados associados a cada tipo de pacote.
+
+Além disso, foram implementadas funções auxiliares para criar instâncias de cada tipo de pacote, como `NewGetUserCert`, `NewGetUnreadMsgsInfo`, `NewGetMsg`, `NewSendMsg`, `NewAnswerGetUserCert`, `NewAnswerGetUnreadMsgsInfo` e `NewAnswerGetMsg`. Estas funções facilitam a criação de pacotes com os dados necessários de forma estruturada.
+
+Para facilitar a serialização e desserialização dos pacotes em formato JSON, foram implementadas funções `Unmarshal` específicas para cada tipo de pacote. Estas funções convertem os dados do pacote entre o formato JSON e as estruturas de dados correspondentes, permitindo a comunicação eficiente entre o cliente e o servidor.
+
+Este package serve como uma camada de abstração que facilita a comunicação entre os componentes cliente e servidor, garantindo que os dados sejam transmitidos de forma estruturada e padronizada, facilitando o desenvolvimento, manutenção e expansão do sistema de comunicação.
+
+## Diagramas 
+
+
+
+
+## Server
+
+### Data Store
+
+
+
+## Client
+
 
 
-## Key Store generation
 
 [Commands used to generate the key stores](./certs/README.md)

Projs/PD1/go.mod

@@ -3,7 +3,9 @@ module PD1
 go 1.22.2
 
 require (
-	github.com/mattn/go-sqlite3 v1.14.22 // indirect
+	github.com/mattn/go-sqlite3 v1.14.22
-	golang.org/x/crypto v0.11.0 // indirect
+	golang.org/x/crypto v0.11.0
-	software.sslmate.com/src/go-pkcs12 v0.4.0 // indirect
+	software.sslmate.com/src/go-pkcs12 v0.4.0
 )
+
+require golang.org/x/sys v0.10.0 // indirect

Projs/PD1/go.sum

@@ -2,5 +2,7 @@ github.com/mattn/go-sqlite3 v1.14.22 h1:2gZY6PC6kBnID23Tichd1K+Z0oS6nE/XwU+Vz/5o
 github.com/mattn/go-sqlite3 v1.14.22/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=
 golang.org/x/crypto v0.11.0 h1:6Ewdq3tDic1mg5xRO4milcWCfMVQhI4NkqWWvqejpuA=
 golang.org/x/crypto v0.11.0/go.mod h1:xgJhtzW8F9jGdVFWZESrid1U1bjeNy4zgy5cRr/CIio=
+golang.org/x/sys v0.10.0 h1:SqMFp9UcQJZa+pmYuAKjd9xq1f0j5rLcDIk0mj4qAsA=
+golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 software.sslmate.com/src/go-pkcs12 v0.4.0 h1:H2g08FrTvSFKUj+D309j1DPfk5APnIdAQAB8aEykJ5k=
 software.sslmate.com/src/go-pkcs12 v0.4.0/go.mod h1:Qiz0EyvDRJjjxGyUQa2cCNZn/wMyzrRJ/qcDXOQazLI=

Projs/PD1/internal/client/client.go

@@ -4,7 +4,11 @@ import (
 	"PD1/internal/protocol"
 	"PD1/internal/utils/cryptoUtils"
 	"PD1/internal/utils/networking"
+	"crypto/x509"
 	"flag"
+	"log"
+	"sort"
+	"strconv"
 )
 
 func Run() {
@@ -15,7 +19,7 @@ func Run() {
 	if flag.NArg() == 0 {
 		panic("No command provided. Use 'help' for instructions.")
 	}
-    //Get user KeyStore
+	//Get user KeyStore
 	password := AskUserPassword()
 	clientKeyStore := cryptoUtils.LoadKeyStore(userFile, password)
 
@@ -26,30 +30,73 @@ func Run() {
 			panic("Insufficient arguments for 'send' command. Usage: send <UID> <SUBJECT>")
 		}
 		uid := flag.Arg(1)
-		//subject := flag.Arg(2)
+		plainSubject := flag.Arg(2)
-		//messageContent := readMessageContent()
+		plainBody := readStdin("Enter message content (limited to 1000 bytes):")
+		//Turn content to bytes
+		plainSubjectBytes := Marshal(plainSubject)
+		plainBodyBytes := Marshal(plainBody)
 
 		cl := networking.NewClient[protocol.Packet](&clientKeyStore)
 		defer cl.Connection.Conn.Close()
 
-		certRequestPacket := protocol.NewRequestUserCertPacket(uid)
+		receiverCert := getUserCert(cl, uid)
-		cl.Connection.Send(certRequestPacket)
+		if receiverCert == nil {
-		//certPacket := cl.Connection.Receive()
+			return
-
+		}
-		// TODO: Encrypt message
+		subject := clientKeyStore.EncryptMessageContent(receiverCert, plainSubjectBytes)
-		//submitMessage(cl, uid, cipherContent)
+		body := clientKeyStore.EncryptMessageContent(receiverCert, plainBodyBytes)
+		sendMsgPacket := protocol.NewSendMsgPacket(uid, subject, body)
+		if !cl.Connection.Send(sendMsgPacket) {
+			return
+		}
+		cl.Connection.Conn.Close()
 
 	case "askqueue":
+		pageInput := flag.Arg(1)
+		page := 1
+		if pageInput != "" {
+			if val, err := strconv.Atoi(pageInput); err == nil {
+				page = max(1, val)
+			}
+		}
+		pageSizeInput := flag.Arg(2)
+		pageSize := 5
+		if pageSizeInput != "" {
+			if val, err := strconv.Atoi(pageSizeInput); err == nil {
+				pageSize = max(1, val)
+			}
+		}
+
 		cl := networking.NewClient[protocol.Packet](&clientKeyStore)
 		defer cl.Connection.Conn.Close()
+        askQueue(cl,clientKeyStore, page, pageSize)
 
 	case "getmsg":
 		if flag.NArg() < 2 {
 			panic("Insufficient arguments for 'getmsg' command. Usage: getmsg <NUM>")
 		}
-		//num := flag.Arg(1)
+		numString := flag.Arg(1)
 		cl := networking.NewClient[protocol.Packet](&clientKeyStore)
 		defer cl.Connection.Conn.Close()
+		num, err := strconv.Atoi(numString)
+		if err != nil {
+			log.Panicln("NUM argument provided is not a number")
+		}
+		packet := protocol.NewGetMsgPacket(num)
+		cl.Connection.Send(packet)
+
+		receivedMsgPacket, active := cl.Connection.Receive()
+		if !active {
+			return
+		}
+		answerGetMsg := protocol.UnmarshalAnswerGetMsg(receivedMsgPacket.Body)
+		senderCert := getUserCert(cl, answerGetMsg.FromUID)
+		decSubjectBytes := clientKeyStore.DecryptMessageContent(senderCert, answerGetMsg.Subject)
+		decBodyBytes := clientKeyStore.DecryptMessageContent(senderCert, answerGetMsg.Body)
+		subject := Unmarshal(decSubjectBytes)
+		body := Unmarshal(decBodyBytes)
+		message := newClientMessage(answerGetMsg.FromUID, answerGetMsg.ToUID, subject, body, answerGetMsg.Timestamp)
+		showMessage(message)
 
 	case "help":
 		showHelp()
@@ -60,7 +107,73 @@ func Run() {
 
 }
 
-func submitMessage(cl networking.Client[protocol.Packet], uid string, content []byte) {
+func getUserCert(cl networking.Client[protocol.Packet], uid string) *x509.Certificate {
-	pack := protocol.NewSubmitMessagePacket(uid, content)
+	getUserCertPacket := protocol.NewGetUserCertPacket(uid)
-	cl.Connection.Send(pack)
+	if !cl.Connection.Send(getUserCertPacket) {
+		return nil
+	}
+	var answerGetUserCertPacket *protocol.Packet
+	answerGetUserCertPacket, active := cl.Connection.Receive()
+	if !active {
+		return nil
+	}
+	answerGetUserCert := protocol.UnmarshalAnswerGetUserCert(answerGetUserCertPacket.Body)
+	userCert, err := x509.ParseCertificate(answerGetUserCert.Certificate)
+	if err != nil {
+		return nil
+	}
+	return userCert
+}
+
+func getManyMessagesInfo(cl networking.Client[protocol.Packet]) (protocol.AnswerGetUnreadMsgsInfo, map[string]*x509.Certificate) {
+	answerGetUnreadMsgsInfoPacket, active := cl.Connection.Receive()
+	if !active {
+		return protocol.NewAnswerGetUnreadMsgsInfo(0, 0, nil), nil
+	}
+	answerGetUnreadMsgsInfo := protocol.UnmarshalAnswerGetUnreadMsgsInfo(answerGetUnreadMsgsInfoPacket.Body)
+
+	//Create Set of needed certificates
+	senderSet := map[string]bool{}
+	for _, messageInfo := range answerGetUnreadMsgsInfo.MessagesInfo {
+		senderSet[messageInfo.FromUID] = true
+	}
+	certificatesMap := map[string]*x509.Certificate{}
+	//Get senders' certificates
+	for senderUID := range senderSet {
+		senderCert := getUserCert(cl, senderUID)
+		certificatesMap[senderUID] = senderCert
+	}
+	return answerGetUnreadMsgsInfo, certificatesMap
+}
+
+func askQueue(cl networking.Client[protocol.Packet],clientKeyStore cryptoUtils.KeyStore, page int, pageSize int) {
+	requestUnreadMsgsQueuePacket := protocol.NewGetUnreadMsgsInfoPacket(page, pageSize)
+	if !cl.Connection.Send(requestUnreadMsgsQueuePacket) {
+		return
+	}
+	unreadMsgsInfo, certificates := getManyMessagesInfo(cl)
+	var clientMessages []ClientMessageInfo
+	for _, message := range unreadMsgsInfo.MessagesInfo {
+		senderCert, ok := certificates[message.FromUID]
+		if ok {
+			decryptedSubjectBytes := clientKeyStore.DecryptMessageContent(senderCert, message.Subject)
+			subject := Unmarshal(decryptedSubjectBytes)
+			clientMessage := newClientMessageInfo(message.Num, message.FromUID, subject, message.Timestamp)
+			clientMessages = append(clientMessages, clientMessage)
+		}
+	}
+	//Sort the messages
+	sort.Slice(clientMessages, func(i, j int) bool {
+		return clientMessages[i].Num > clientMessages[j].Num
+	})
+
+    action := showMessagesInfo(unreadMsgsInfo.Page, unreadMsgsInfo.NumPages, clientMessages)
+    switch action {
+    case -1:
+        askQueue(cl, clientKeyStore , max(1,unreadMsgsInfo.Page-1) , pageSize) 
+    case 0:
+        return
+    case 1:
+        askQueue(cl, clientKeyStore , max(1,unreadMsgsInfo.Page+1) , pageSize) 
+    }
 }

Projs/PD1/internal/client/datastore.go

@@ -1,15 +1,47 @@
 package client
 
-import "time"
+import (
+	"encoding/json"
+	"log"
+	"time"
+)
 
-type Content struct {
+type ClientMessage struct {
-	Subject []byte
-	Body    []byte
-}
-
-type RecievedMessage struct {
 	FromUID   string
 	ToUID     string
-	Content   Content
+	Subject   string
+	Body      string
 	Timestamp time.Time
 }
+
+type ClientMessageInfo struct {
+	Num       int
+	FromUID   string
+	Timestamp time.Time
+	Subject   string
+}
+
+func newClientMessage(fromUID string, toUID string, subject string, body string, timestamp time.Time) ClientMessage {
+	return ClientMessage{FromUID: fromUID, ToUID: toUID, Subject: subject, Body: body, Timestamp: timestamp}
+}
+
+func newClientMessageInfo(num int, fromUID string, subject string, timestamp time.Time) ClientMessageInfo {
+    return ClientMessageInfo{Num:num,FromUID: fromUID,Subject: subject,Timestamp: timestamp}
+}
+
+func Marshal(data any) []byte {
+	subject, err := json.Marshal(data)
+	if err != nil {
+		log.Panicf("Error when marshalling message: %v", err)
+	}
+	return subject
+}
+
+func Unmarshal(data []byte) string {
+	var c string
+	err := json.Unmarshal(data, &c)
+	if err != nil {
+		log.Panicln("Could not unmarshal data")
+	}
+	return c
+}

Projs/PD1/internal/client/interface.go

@@ -4,10 +4,11 @@ import (
 	"bufio"
 	"fmt"
 	"os"
+	"strings"
 )
 
-func readMessageContent() string {
+func readStdin(message string) string {
-	fmt.Println("Enter message content (limited to 1000 bytes):")
+	fmt.Println(message)
 	scanner := bufio.NewScanner(os.Stdin)
 	scanner.Scan()
 	// FIX: make sure this doesnt die
@@ -23,11 +24,10 @@ func AskUserPassword() string {
 }
 
 func commandError() {
-    fmt.Println("MSG SERVICE: command error!")
+	fmt.Println("MSG SERVICE: command error!")
-    showHelp()
+	showHelp()
 }
 
-
 func showHelp() {
 	fmt.Println("Comandos da aplicação cliente:")
 	fmt.Println("-user <FNAME>: Especifica o ficheiro com dados do utilizador. Por omissão, será assumido que esse ficheiro é userdata.p12.")
@@ -36,3 +36,64 @@ func showHelp() {
 	fmt.Println("getmsg <NUM>: Solicita ao servidor o envio da mensagem da sua queue com número <NUM>.")
 	fmt.Println("help: Imprime instruções de uso do programa.")
 }
+
+func showMessagesInfo(page int, numPages int, messages []ClientMessageInfo) int {
+	if messages == nil {
+		fmt.Println("No unread messages in the queue")
+		return 0
+	}
+	for _, message := range messages {
+		fmt.Printf("%v:%v:%v:%v\n", message.Num, message.FromUID, message.Timestamp, message.Subject)
+	}
+    fmt.Printf("Page %v/%v\n",page,numPages)
+	return messagesInfoPageNavigation(page, numPages)
+}
+
+func messagesInfoPageNavigation(page int, numPages int) int {
+	var action string
+
+	switch page {
+	case 1:
+		if page == numPages {
+			action = readStdin("Actions: quit")
+		} else {
+			action = readStdin("Actions: quit/next")
+		}
+	case numPages:
+		action = readStdin("Actions: prev/quit")
+	default:
+		action = readStdin("prev/quit/next")
+	}
+
+	switch strings.ToLower(action) {
+	case "prev":
+		if page == 1 {
+			fmt.Println("Unavailable action: Already in first page")
+			messagesInfoPageNavigation(page, numPages)
+		} else {
+			return -1
+		}
+	case "quit":
+		return 0
+	case "next":
+		if page == numPages {
+			fmt.Println("Unavailable action: Already in last page")
+			messagesInfoPageNavigation(page, numPages)
+		} else {
+			return 1
+		}
+	default:
+		fmt.Println("Unknown action")
+		messagesInfoPageNavigation(page, numPages)
+	}
+	return 0
+}
+
+
+func showMessage(message ClientMessage) {
+	fmt.Printf("From: %s\n", message.FromUID)
+	fmt.Printf("To: %s\n", message.ToUID)
+	fmt.Printf("Subject: %s\n", message.Subject)
+	fmt.Printf("Body: %s\n", message.Body)
+}
+

Projs/PD1/internal/protocol/protocol.go

@@ -1,116 +1,272 @@
 package protocol
 
 import (
+	"encoding/json"
+	"fmt"
 	"time"
 )
 
 type PacketType int
 
 const (
-	ReqUserCertPkt PacketType = iota
+	// Client requests user certificate
-	ReqAllMsgPkt
+	FlagGetUserCert PacketType = iota
-	ReqMsgPkt
+
-	SubmitMsgPkt
+	// Client requests unread message info
-	SendUserCertPkt
+	FlagGetUnreadMsgsInfo
-	ServerMsgPkt
+
+	// Client requests a message from the queue
+	FlagGetMsg
+
+	// Client sends a message
+	FlagSendMsg
+
+	// Server sends user certificate
+	FlagAnswerGetUserCert
+
+	// Server sends list of unread messages
+	FlagAnswerGetUnreadMsgsInfo
+
+	// Server sends requested message
+	FlagAnswerGetMsg
+)
+
+type (
+	GetUserCert struct {
+		UID string `json:"uid"`
+	}
+
+	GetUnreadMsgsInfo struct {
+		Page     int `json:"page"`
+		PageSize int `json:"pageSize"`
+	}
+
+	GetMsg struct {
+		Num int `json:"num"`
+	}
+
+	SendMsg struct {
+		ToUID   string `json:"to_uid"`
+		Subject []byte `json:"subject"`
+		Body    []byte `json:"body"`
+	}
+
+	AnswerGetUserCert struct {
+		UID         string `json:"uid"`
+		Certificate []byte `json:"certificate"`
+	}
+
+	AnswerGetUnreadMsgsInfo struct {
+		Page         int       `json:"page"`
+		NumPages     int       `json:"num_pages"`
+		MessagesInfo []MsgInfo `json:"messages_info"`
+	}
+
+	MsgInfo struct {
+		Num       int       `json:"num"`
+		FromUID   string    `json:"from_uid"`
+		Subject   []byte    `json:"subject"`
+		Timestamp time.Time `json:"timestamp"`
+	}
+
+	AnswerGetMsg struct {
+		FromUID   string    `json:"from_uid"`
+		ToUID     string    `json:"to_uid"`
+		Subject   []byte    `json:"subject"`
+		Body      []byte    `json:"body"`
+		Timestamp time.Time `json:"timestamp"`
+	}
 )
 
 type PacketBody interface{}
 
 type Packet struct {
-	Flag PacketType
+	Flag PacketType `json:"flag"`
-	Body PacketBody
+	Body PacketBody `json:"body"`
 }
 
-// Client --> Server: Ask for a user's certificate
+func NewPacket(fl PacketType, body PacketBody) Packet {
-type RequestUserCertPacket struct {
-	UID string
-}
-
-func NewRequestUserCertPacket(UID string) Packet {
 	return Packet{
-		Flag: ReqUserCertPkt,
+		Flag: fl,
-		Body: RequestUserCertPacket{
+		Body: body,
-			UID: UID,
+	}
-		},
+
+}
+
+func NewGetUserCert(UID string) GetUserCert {
+	return GetUserCert{
+		UID: UID,
 	}
 }
 
-// Client --> Server: Ask for all the client's messages in the queue
+func NewGetUnreadMsgsInfo(page int, pageSize int) GetUnreadMsgsInfo {
-type RequestAllMsgPacket struct {
+	return GetUnreadMsgsInfo{
-	FromUID string
+		Page:     page,
+		PageSize: pageSize}
 }
 
-func NewRequestAllMsgPacket(fromUID string) Packet {
+func NewGetMsg(num int) GetMsg {
-	return Packet{
+	return GetMsg{
-		Flag: ReqAllMsgPkt,
+		Num: num,
-		Body: RequestAllMsgPacket{
-			FromUID: fromUID,
-		},
 	}
 }
 
-// Client --> Server: Ask for a specific message in the queue
+func NewSendMsg(toUID string, subject []byte, body []byte) SendMsg {
-type RequestMsgPacket struct {
+	return SendMsg{
-	Num uint16
+		ToUID:   toUID,
-}
+		Subject: subject,
-
+		Body:    body,
-func NewRequestMsgPacket(num uint16) Packet {
-	return Packet{
-		Flag: ReqMsgPkt,
-		Body: RequestMsgPacket{
-			Num: num,
-		},
 	}
 }
 
-// Client --> Server: Send message from client to server
+func NewAnswerGetUserCert(uid string, certificate []byte) AnswerGetUserCert {
-type SubmitMessagePacket struct {
+	return AnswerGetUserCert{
-	ToUID   string
+		UID:         uid,
-	Content []byte
+		Certificate: certificate,
-}
-
-func NewSubmitMessagePacket(toUID string, content []byte) Packet {
-	return Packet{
-		Flag: SubmitMsgPkt,
-		Body: SubmitMessagePacket{
-			ToUID:   toUID,
-			Content: content},
 	}
 }
 
-// Server --> Client: Send the client the requested public key
+func NewAnswerGetUnreadMsgsInfo(page int, numPages int, messagesInfo []MsgInfo) AnswerGetUnreadMsgsInfo {
-type SendUserCertPacket struct {
+    return AnswerGetUnreadMsgsInfo{Page:page,NumPages:numPages,MessagesInfo: messagesInfo}
-	UID string
-	Key []byte
 }
-
+func NewMsgInfo(num int, fromUID string, subject []byte, timestamp time.Time) MsgInfo {
-func NewSendUserCertPacket(uid string, key []byte) Packet {
+	return MsgInfo{
-	return Packet{
+		Num:       num,
-		Flag: SendUserCertPkt,
+		FromUID:   fromUID,
-		Body: SendUserCertPacket{
+		Subject:   subject,
-			UID: uid,
+		Timestamp: timestamp,
-			Key: key,
-		},
 	}
 }
 
-// Server --> Client: Send the client a message
+func NewAnswerGetMsg(fromUID, toUID string, subject []byte, body []byte, timestamp time.Time, last bool) AnswerGetMsg {
-type ServerMessagePacket struct {
+	return AnswerGetMsg{
-	FromUID   string
+		FromUID:   fromUID,
-	ToUID     string
+		ToUID:     toUID,
-	Content   []byte
+		Subject:   subject,
-	Timestamp time.Time
+		Body:      body,
-}
+		Timestamp: timestamp,
-
-func NewServerMessagePacket(fromUID, toUID string, content []byte, timestamp time.Time) Packet {
-	return Packet{
-		Flag: ServerMsgPkt,
-		Body: ServerMessagePacket{
-			FromUID:   fromUID,
-			ToUID:     toUID,
-			Content:   content,
-			Timestamp: timestamp,
-		},
 	}
 }
+
+func NewGetUserCertPacket(UID string) Packet {
+	return NewPacket(FlagGetUserCert, NewGetUserCert(UID))
+}
+
+func NewGetUnreadMsgsInfoPacket(page int, pageSize int) Packet {
+	return NewPacket(FlagGetUnreadMsgsInfo, NewGetUnreadMsgsInfo(page, pageSize))
+}
+
+func NewGetMsgPacket(num int) Packet {
+	return NewPacket(FlagGetMsg, NewGetMsg(num))
+}
+
+func NewSendMsgPacket(toUID string, subject []byte, body []byte) Packet {
+	return NewPacket(FlagSendMsg, NewSendMsg(toUID, subject, body))
+}
+
+func NewAnswerGetUserCertPacket(uid string, certificate []byte) Packet {
+	return NewPacket(FlagAnswerGetUserCert, NewAnswerGetUserCert(uid, certificate))
+}
+
+func NewAnswerGetUnreadMsgsInfoPacket(page int, numPages int, messagesInfo []MsgInfo) Packet {
+	return NewPacket(FlagAnswerGetUnreadMsgsInfo, NewAnswerGetUnreadMsgsInfo(page,numPages,messagesInfo))
+}
+
+func NewAnswerGetMsgPacket(fromUID, toUID string, subject []byte, body []byte, timestamp time.Time, last bool) Packet {
+	return NewPacket(FlagAnswerGetMsg, NewAnswerGetMsg(fromUID, toUID, subject, body, timestamp, last))
+}
+
+func UnmarshalGetUserCert(data PacketBody) GetUserCert {
+	jsonData, err := json.Marshal(data)
+	if err != nil {
+		panic(fmt.Errorf("failed to marshal data: %v", err))
+	}
+	var packet GetUserCert
+	if err := json.Unmarshal(jsonData, &packet); err != nil {
+		panic(fmt.Errorf("failed to unmarshal into GetUserCert: %v", err))
+	}
+	return packet
+}
+
+func UnmarshalGetUnreadMsgsInfo(data PacketBody) GetUnreadMsgsInfo {
+	jsonData, err := json.Marshal(data)
+	if err != nil {
+		panic(fmt.Errorf("failed to marshal data: %v", err))
+	}
+	var packet GetUnreadMsgsInfo
+	if err := json.Unmarshal(jsonData, &packet); err != nil {
+		panic(fmt.Errorf("failed to unmarshal into GetUnreadMsgsInfo: %v", err))
+	}
+	return packet
+}
+
+func UnmarshalGetMsg(data PacketBody) GetMsg {
+	jsonData, err := json.Marshal(data)
+	if err != nil {
+		panic(fmt.Errorf("failed to marshal data: %v", err))
+	}
+	var packet GetMsg
+	if err := json.Unmarshal(jsonData, &packet); err != nil {
+		panic(fmt.Errorf("failed to unmarshal into GetMsg: %v", err))
+	}
+	return packet
+}
+
+func UnmarshalSendMsg(data PacketBody) SendMsg {
+	jsonData, err := json.Marshal(data)
+	if err != nil {
+		panic(fmt.Errorf("failed to marshal data: %v", err))
+	}
+	var packet SendMsg
+	if err := json.Unmarshal(jsonData, &packet); err != nil {
+		panic(fmt.Errorf("failed to unmarshal into SendMsg: %v", err))
+	}
+	return packet
+}
+
+func UnmarshalAnswerGetUserCert(data PacketBody) AnswerGetUserCert {
+	jsonData, err := json.Marshal(data)
+	if err != nil {
+		panic(fmt.Errorf("failed to marshal data: %v", err))
+	}
+	var packet AnswerGetUserCert
+	if err := json.Unmarshal(jsonData, &packet); err != nil {
+		panic(fmt.Errorf("failed to unmarshal into AnswerGetUserCert: %v", err))
+	}
+	return packet
+}
+func UnmarshalUnreadMsgInfo(data PacketBody) MsgInfo {
+	jsonData, err := json.Marshal(data)
+	if err != nil {
+		panic(fmt.Errorf("failed to marshal data: %v", err))
+	}
+	var packet MsgInfo
+	if err := json.Unmarshal(jsonData, &packet); err != nil {
+		panic(fmt.Errorf("failed to unmarshal into UnreadMsgInfo: %v", err))
+	}
+	return packet
+}
+
+func UnmarshalAnswerGetUnreadMsgsInfo(data PacketBody) AnswerGetUnreadMsgsInfo {
+	jsonData, err := json.Marshal(data)
+	if err != nil {
+		panic(fmt.Errorf("failed to marshal data: %v", err))
+	}
+	var packet AnswerGetUnreadMsgsInfo
+	if err := json.Unmarshal(jsonData, &packet); err != nil {
+		panic(fmt.Errorf("failed to unmarshal into AnswerGetUnreadMsgsInfo: %v", err))
+	}
+	return packet
+}
+
+func UnmarshalAnswerGetMsg(data PacketBody) AnswerGetMsg {
+	jsonData, err := json.Marshal(data)
+	if err != nil {
+		panic(fmt.Errorf("failed to marshal data: %v", err))
+	}
+	var packet AnswerGetMsg
+	if err := json.Unmarshal(jsonData, &packet); err != nil {
+		panic(fmt.Errorf("failed to unmarshal into AnswerGetMsg: %v", err))
+	}
+	return packet
+}

Projs/PD1/internal/server/datastore.go

@@ -2,7 +2,9 @@ package server
 
 import (
 	"PD1/internal/protocol"
+	"crypto/x509"
 	"database/sql"
+	"fmt"
 	"log"
 	"time"
 
@@ -18,7 +20,9 @@ func OpenDB() DataStore {
 	if err != nil {
 		log.Fatalln("Error opening db file")
 	}
-	return DataStore{db: db}
+	ds := DataStore{db: db}
+	ds.CreateTables()
+	return ds
 }
 
 func (ds DataStore) CreateTables() error {
@@ -28,6 +32,7 @@ func (ds DataStore) CreateTables() error {
         userCert BLOB
     )`)
 	if err != nil {
+		fmt.Println("Error creating users table", err)
 		return err
 	}
 
@@ -36,106 +41,144 @@ func (ds DataStore) CreateTables() error {
         fromUID TEXT,
         toUID TEXT,
         timestamp TIMESTAMP,
-        content BLOB,
+        queue_position INT DEFAULT 0,
+        subject BLOB,
+        body BLOB,
+        status INT CHECK (status IN (0,1)),
         PRIMARY KEY (toUID, fromUID, timestamp),
         FOREIGN KEY(fromUID) REFERENCES users(UID),
         FOREIGN KEY(toUID) REFERENCES users(UID)
     )`)
 	if err != nil {
+		fmt.Println("Error creating messages table", err)
+		return err
+	}
+
+	// Define a trigger to automatically assign numbers for each message of each user starting from 1
+	_, err = ds.db.Exec(`
+        CREATE TRIGGER IF NOT EXISTS assign_queue_position
+        AFTER INSERT ON messages
+        FOR EACH ROW
+        BEGIN
+            UPDATE messages
+            SET queue_position = (
+                SELECT COUNT(*)
+                FROM messages
+                WHERE toUID = NEW.toUID
+            )
+            WHERE toUID = NEW.toUID AND rowid = NEW.rowid;
+        END;
+    `)
+	if err != nil {
+		fmt.Println("Error creating trigger", err)
 		return err
 	}
 
 	return nil
 }
 
-func (ds DataStore) GetMessage(toUID string, position int) protocol.ServerMessagePacket {
+func (ds DataStore) GetMessage(toUID string, position int) protocol.Packet {
 
-	var serverMessage protocol.ServerMessagePacket
+	var serverMessage protocol.AnswerGetMsg
 	query := `
-        SELECT fromUID, toUID, content, timestamp
+        SELECT fromUID, toUID, subject, body, timestamp
         FROM messages
-        WHERE toUID = ?
+        WHERE toUID = ? AND queue_position = ?
-        AND status = 0
-        ORDER BY timestamp
-        LIMIT 1 OFFSET ?
     `
 	// Execute the query
 	row := ds.db.QueryRow(query, toUID, position)
-	err := row.Scan(&serverMessage.FromUID, &serverMessage.ToUID, &serverMessage.Content, &serverMessage.Timestamp)
+	err := row.Scan(&serverMessage.FromUID, &serverMessage.ToUID, &serverMessage.Subject, &serverMessage.Body, &serverMessage.Timestamp)
 	if err != nil {
-		log.Panicln("Could not map DB query to ServerMessage")
+		log.Printf("Error getting the message in position %v from UID %v: %v", position, toUID, err)
 	}
-	return serverMessage
+
+	return protocol.NewAnswerGetMsgPacket(serverMessage.FromUID, serverMessage.ToUID, serverMessage.Subject, serverMessage.Body, serverMessage.Timestamp, true)
 
 }
 
-func (ds DataStore) MarkMessageInQueueAsRead(toUID string, position int) error {
+func (ds DataStore) MarkMessageInQueueAsRead(toUID string, position int) {
 	query := `
         UPDATE messages
-        SET status = 1
+            SET status = 1
-        WHERE toUID = ? AND status = 0
+            WHERE (fromUID,toUID,timestamp) = (
-        ORDER BY timestamp
+                SELECT fromUID,toUID,timestamp
-        LIMIT 1 OFFSET ?
+                FROM messages
+                WHERE toUID = ? AND queue_position = ?
+            )
     `
 
 	// Execute the SQL statement
 	_, err := ds.db.Exec(query, toUID, position)
 	if err != nil {
-		return err
+		log.Printf("Error marking the message in position %v from UID %v as read: %v", position, toUID, err)
 	}
-
-	return nil
 }
 
-func (ds DataStore) GetAllMessages(toUID string) []protocol.Packet {
+func (ds DataStore) GetUnreadMsgsInfo(toUID string, page int, pageSize int) protocol.Packet {
-	var messagePackets []protocol.Packet
+
+	// Retrieve the total count of unread messages
+	var totalCount int
+	err := ds.db.QueryRow("SELECT COUNT(*) FROM messages WHERE toUID = ? AND status = 0", toUID).Scan(&totalCount)
+	if err != nil {
+		log.Printf("Error getting total count of unread messages for UID %v: %v", toUID, err)
+	}
 
 	// Query to retrieve all messages from the user's queue
 	query := `
-        SELECT fromUID, toUID, content, timestamp
+        SELECT 
+            fromUID,
+            toUID,
+            timestamp,
+            queue_position,
+            subject,
+            status
         FROM messages
-        WHERE toUID = ?
+        WHERE 
-        AND status = 0
+            toUID = ? AND status = 0
-        ORDER BY timestamp
+        ORDER BY 
+            queue_position DESC
+        LIMIT ? OFFSET ?;
     `
 
 	// Execute the query
-	rows, err := ds.db.Query(query, toUID)
+	rows, err := ds.db.Query(query, toUID, pageSize, (page-1)*pageSize)
 	if err != nil {
-		log.Panicln("Failed to execute query:", err)
+		log.Printf("Error getting all messages for UID %v: %v", toUID, err)
 	}
 	defer rows.Close()
 
-	// Iterate through the result set and scan each row into a ServerMessage struct
+	messageInfoPackets := []protocol.MsgInfo{}
 	for rows.Next() {
 		var fromUID string
-		var toUID string
+		var subject []byte
-		var content []byte
 		var timestamp time.Time
-		if err := rows.Scan(&fromUID, &toUID, &content, &timestamp); err != nil {
+		var queuePosition, status int
-			log.Panicln("Failed to scan row:", err)
+		if err := rows.Scan(&fromUID, &toUID, &timestamp, &queuePosition, &subject, &status); err != nil {
+			panic(err)
 		}
-		message := protocol.NewServerMessagePacket(fromUID, toUID, content, timestamp)
+		answerGetUnreadMsgsInfo := protocol.NewMsgInfo(queuePosition, fromUID, subject, timestamp)
-		messagePackets = append(messagePackets, message)
+		messageInfoPackets = append(messageInfoPackets, answerGetUnreadMsgsInfo)
 	}
 	if err := rows.Err(); err != nil {
-		log.Panicln("Error when getting user's messages")
+		log.Printf("Error when getting messages for UID %v: %v", toUID, err)
 	}
 
-	return messagePackets
+	numberOfPages := (totalCount + pageSize - 1) / pageSize
+	currentPage := min(numberOfPages, page)
+	return protocol.NewAnswerGetUnreadMsgsInfoPacket(currentPage, numberOfPages, messageInfoPackets)
 }
 
-func (ds DataStore) AddMessageToQueue(uid string, message protocol.SubmitMessagePacket) {
+func (ds DataStore) AddMessageToQueue(fromUID string, message protocol.SendMsg) {
 	query := `
-        INSERT INTO messages (fromUID, toUID, content, timestamp, status)
+        INSERT INTO messages (fromUID, toUID, subject, body, timestamp, status)
-        VALUES (?, ?, ?, ?, 0)
+        VALUES (?, ?, ?, ?, ?, 0)
     `
 
 	// Execute the SQL statement
 	currentTime := time.Now()
-	_, err := ds.db.Exec(query, uid, message.ToUID, message.Content, currentTime)
+	_, err := ds.db.Exec(query, fromUID, message.ToUID, message.Subject, message.Body, currentTime)
 	if err != nil {
-		log.Panicln("Error adding message to database")
+		log.Printf("Error adding message to UID %v: %v", fromUID, err)
 	}
 }
 
@@ -147,10 +190,53 @@ func (ds DataStore) GetUserCertificate(uid string) protocol.Packet {
     `
 
 	// Execute the SQL query
-	var userCert []byte
+	var userCertBytes []byte
-	err := ds.db.QueryRow(query, uid).Scan(&userCert)
+	err := ds.db.QueryRow(query, uid).Scan(&userCertBytes)
-	if err != nil {
+	if err == sql.ErrNoRows {
-		log.Panicln("Error getting user certificate from the database")
+		log.Panicf("No certificate for UID %v found in the database", uid)
 	}
-	return protocol.NewSendUserCertPacket(uid, userCert)
+	//userCert,err := x509.ParseCertificate(userCertBytes)
+	//if err!=nil {
+	//    log.Panicf("Error parsing certificate for UID %v",uid)
+	//}
+	return protocol.NewAnswerGetUserCertPacket(uid, userCertBytes)
+}
+
+func (ds DataStore) userExists(uid string) bool {
+	// Prepare the SQL statement for checking if a user exists
+	query := `
+        SELECT COUNT(*)
+        FROM users
+        WHERE UID = ?
+    `
+
+	var count int
+	// Execute the SQL query
+	err := ds.db.QueryRow(query, uid).Scan(&count)
+	if err == sql.ErrNoRows {
+		log.Printf("User with UID %v does not exist", uid)
+		return false
+	} else {
+		return true
+	}
+}
+
+func (ds DataStore) storeUserCertIfNotExists(uid string, cert x509.Certificate) {
+	// Check if the user already exists
+	if ds.userExists(uid) {
+		log.Printf("User certificate for UID %s already exists.\n", uid)
+		return
+	}
+
+	// Insert the user certificate
+	insertQuery := `
+        INSERT INTO users (UID, userCert)
+        VALUES (?, ?)
+    `
+	_, err := ds.db.Exec(insertQuery, uid, cert.Raw)
+	if err != nil {
+		log.Printf("Error storing user certificate for UID %s: %v\n", uid, err)
+		return
+	}
+	log.Printf("User certificate for UID %s stored successfully.\n", uid)
 }

Projs/PD1/internal/server/server.go

@@ -4,28 +4,58 @@ import (
 	"PD1/internal/protocol"
 	"PD1/internal/utils/cryptoUtils"
 	"PD1/internal/utils/networking"
-	"fmt"
 )
 
+//TODO: CREATE SERVER SIDE CHECKS FOR EVERYTHING
+//TODO: LOGGING SYSTEM
+//TODO: TELL THE USER THAT THE MESSAGE HAS BEEN RECEIVED BY THE SERVER
+//TODO: ERROR PACKET TO SEND BACK TO USER
+
 func clientHandler(connection networking.Connection[protocol.Packet], dataStore DataStore) {
 	defer connection.Conn.Close()
-	_ = dataStore
-	clientCert := connection.GetPeerCertificate()
-	oidValueMap := cryptoUtils.ExtractAllOIDValues(clientCert)
-	fmt.Println(oidValueMap)
 
+	//Get certificate sent by user
+	clientCert := connection.GetPeerCertificate()
+	//Get the OID values
+	oidMap := cryptoUtils.ExtractAllOIDValues(clientCert)
+	//Get the UID of this user
+	UID := oidMap["2.5.4.65"]
+	if UID == "" {
+		panic("User certificate does not specify it's PSEUDONYM")
+	}
+	dataStore.storeUserCertIfNotExists(UID, *clientCert)
+F:
 	for {
-		pac := connection.Receive()
+		pac, active := connection.Receive()
+		if !active {
+			break
+		}
 		switch pac.Flag {
-		case protocol.ReqUserCertPkt:
+		case protocol.FlagGetUserCert:
-			//userCertPacket := dataStore.GetUserCertificate(uid)
+			reqUserCert := protocol.UnmarshalGetUserCert(pac.Body)
-			//connection.Send(userCertPacket)
+			userCertPacket := dataStore.GetUserCertificate(reqUserCert.UID)
-		case protocol.ReqAllMsgPkt:
+			if active := connection.Send(userCertPacket); !active {
-			fmt.Println("ReqAllMsg")
+				break F
-		case protocol.ReqMsgPkt:
+			}
-			fmt.Println("ReqMsg")
+		case protocol.FlagGetUnreadMsgsInfo:
-		case protocol.SubmitMsgPkt:
+			getUnreadMsgsInfo := protocol.UnmarshalGetUnreadMsgsInfo(pac.Body)
-			fmt.Println("SubmitMsg")
+			messages := dataStore.GetUnreadMsgsInfo(UID,getUnreadMsgsInfo.Page,getUnreadMsgsInfo.PageSize)
+			if !connection.Send(messages) {
+				break F
+			}
+		case protocol.FlagGetMsg:
+			reqMsg := protocol.UnmarshalGetMsg(pac.Body)
+			message := dataStore.GetMessage(UID, reqMsg.Num)
+			if active := connection.Send(message); !active {
+				break F
+			}
+			dataStore.MarkMessageInQueueAsRead(UID, reqMsg.Num)
+		case protocol.FlagSendMsg:
+			submitMsg := protocol.UnmarshalSendMsg(pac.Body)
+			if submitMsg.ToUID != UID && dataStore.userExists(submitMsg.ToUID) {
+				dataStore.AddMessageToQueue(UID, submitMsg)
+			}
+
 		}
 	}
 

Projs/PD1/internal/utils/cryptoUtils/cryptoUtils.go

@@ -94,9 +94,8 @@ func (k *KeyStore) GetServerTLSConfig() *tls.Config {
 		caCertPool.AddCert(caCert)
 	}
 	tlsConfig.ClientCAs = caCertPool
-	//Request one valid or invalid certificate
+    //FIX: SERVER ACCEPTS CONNECTIONS WITH UNMATCHING OR 
-	// FIX: SERVER ACCEPTS CONNECTIONS WITH UNMATCHING OR
+    // NO CERTIFICATE, NEEDS TO BE CHANGED SOMEHOW
-	// NO CERTIFICATE, NEEDS TO BE CHANGED SOMEHOW
 	tlsConfig.ClientAuth = tls.RequireAndVerifyClientCert
 	return tlsConfig
 }

Projs/PD1/internal/utils/networking/connection.go

@@ -4,6 +4,8 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"encoding/json"
+	"io"
+	"log"
 )
 
 type Connection[T any] struct {
@@ -20,18 +22,33 @@ func NewConnection[T any](netConn *tls.Conn) Connection[T] {
 	}
 }
 
-func (c Connection[T]) Send(obj T) {
+func (c Connection[T]) Send(obj T) bool {
-	if err := c.encoder.Encode(&obj); err != nil {
+    if err := c.encoder.Encode(&obj); err!=nil {
-		panic("Failed encoding data or sending it to connection")
+		if err == io.EOF {
-	}
+			log.Println("Connection closed by peer")
+            //Return false as connection not active
+			return false
+		} else {
+			log.Panic(err)
+		}
+    }
+    //Return true as connection active
+    return true
 }
 
-func (c Connection[T]) Receive() T {
+func (c Connection[T]) Receive() (*T, bool) {
 	var obj T
 	if err := c.decoder.Decode(&obj); err != nil {
-		panic("Failed decoding data or reading it from connection")
+		if err == io.EOF {
+			log.Println("Connection closed by peer")
+            //Return false as connection not active
+			return nil,false 
+		} else {
+			log.Panic(err)
+		}
 	}
-	return obj
+    //Return true as connection active
+	return &obj, true
 }
 
 func (c Connection[T]) GetPeerCertificate() *x509.Certificate {

Projs/PD1/internal/utils/networking/server.go

@@ -43,7 +43,6 @@ func (s *Server[T]) ListenLoop() {
 
 		state := tlsConn.ConnectionState()
 		if len(state.PeerCertificates) == 0 {
-            fmt.Println(state.PeerCertificates)
 			log.Panicln("Client did not provide a certificate")
 		}
 		conn := NewConnection[T](tlsConn)

Projs/PD1/tokefile.toml

@@ -10,21 +10,16 @@ cmd="@@"
 cmd="go build"
 
 [targets.server]
-deps=["check"]
 cmd="go run ./cmd/server/server.go"
 
 [targets.client1]
-deps=["check"]
+cmd="go run ./cmd/client/client.go -user certs/client1/client1.p12 send CL2 testsubject"
-cmd="go run ./cmd/client/client.go -user certs/client1/client1.p12 send CLI1 testsubject"
 
 [targets.FakeClient1]
-deps=["check"]
+cmd="go run ./cmd/client/client.go -user certs/FakeClient1/client1.p12 send CL2 testsubject"
-cmd="go run ./cmd/client/client.go -user certs/FakeClient1/client1.p12 send CLI1 testsubject"
 
 [targets.client2]
-deps=["check"]
+cmd="go run ./cmd/client/client.go -user certs/client2/client2.p12 send CL3 testsubject"
-cmd="go run ./cmd/client/client.go -user certs/client2/client2.p12 send CLI1 testsubject"
 
 [targets.client3]
-deps=["check"]
+cmd="go run ./cmd/client/client.go -user certs/client3/client3.p12 send CL1 testsubject"
-cmd="go run ./cmd/client/client.go -user certs/client3/client3.p12 send CLI1 testsubject"