merge

Notes.md

@@ -1 +1,15 @@
 # Notes et recherches sur le projet
+
+Arithétique et ordres modulo
+
+s ⊕ n = (s+n) % 2^(16)
+s ⊕ n = (s + n) and 65535
+
+s ≼ s ′ lorsque ((s ′ − s) mod 2 16 ) < 32768
+s ≼ s ′ lorsque ((s ′ − s) and 32768) = 0
+
+-------
+
+jch.irif.fr port UDP 1212
+
+http://jch.irif.fr:8082/

parser.c

@@ -1,31 +0,0 @@
-#include "parser.h"
-
-// retourne le type de commande à exécuter
-cmd_token parse_cmd() {
-	char buf[198], cmd[5], arg[193];
-	cmd_token token;
-	token.type = ERROR;
-	memset(token.arg, 0, 193);
-
-	if(fgets(buf, 198, stdin) == NULL)
-		return token;
-
-	// cmd sera le premier mot rencontré et arg la suite de mots après celui ci, si les deux variables ne sont pas remplies alors il y a une erreur
-	if(sscanf(buf, "%s %[^\t\n]", cmd, arg) != 2)
-		return token;
-
-	if(strcmp("req", cmd) == 0) {
-		if(strcmp("neighbour", arg) == 0) 
-			token.type = NEIGHBOUR_REQ;
-		else if(strcmp("network state", arg) == 0)
-			token.type = NETWORK_STATE_REQ;
-		else if(strcmp("node state", arg) == 0)
-			token.type = NODE_STATE_REQ;
-	} else if(strcmp("post", cmd) == 0) {
-		token.type = POST;
-		//arg[192] = 0;
-		strcpy(token.arg, arg);
-	}
-
-	return token;
-}

parser.h

@@ -1,14 +0,0 @@
-#include <stdio.h>
-#include <string.h>
-
-typedef enum cmd_type {
-	NEIGHBOUR_REQ, NETWORK_STATE_REQ, NODE_STATE_REQ, POST, ERROR
-} cmd_type;
-
-typedef struct cmd_token {
-	cmd_type type;
-	char arg[193];
-} cmd_token;
-
-// retourne le type de commande à exécuter
-cmd_token parse_cmd();

src/node.c

@@ -0,0 +1,94 @@
+// This is the main file of the Dazibao project. It represents the node, and
+// handles all of the main logic, including the network connexions.
+
+
+// Will return a packet when we receive one that's valid.
+packet listen_for_packets(){
+
+}
+
+// We need to make sure the TLV announces a length that will no go onto
+// another tlv, as we might end up reading bullshit.
+int validate_tlvs(union tlv tlv_to_validate){
+
+}
+
+void work_with_tlvs(struct tlvs_list receivied_tlvs){
+
+    // For every TLV,
+        // We make sure the TLV is legal.
+        if(!validate_tlvs(tlv)){
+            perror(">> Invalid TLV receivied, it will be ignored.");
+        }
+
+    // Switch
+
+    // TLV Network Hash
+        // We calculate a network hash,
+
+        // We compare both,
+
+        // If they differ, we send a TLV Network State Request
+        // back to the sender.
+
+    // TLV Network State Request
+        // We check our neighbourhood, and for each peer, we send back
+        // to the sender a TLV Node Hash
+
+    // TLV Node hash
+        // We get a hash _h_ for the node _l_
+        // If we don't have an entry for _l_, or if we have the same one as the
+        // on we just receivied, we send out a TLV Node State Request back.
+
+    // TLV Node State
+        // We get a hash _h_, sequence number _s_, data _d_ for node _l_.
+        // We compute a network hash,
+        // We compare the hash, if they differ, then with l',s',d' our data and
+        // h' the corresponding hash,
+            // if _l_ is our own node id, then
+                // if s >> s' then we update our sequence number to s ⊕ 1 mod 2^16
+            // If it's another's node id, then
+                // If there is no entry for the sender,
+                // we store the entry in our data table.
+}
+
+int main(int argc, char const *argv[]) {
+    int continue = 1;
+    
+    while(continue){
+
+        // We create the neighbourhood table
+        neighbour_peer neighbour_list[NEIGHBOUR_MAX];
+        // We create the message table
+
+        // We create our own message.
+
+        // Listen for incoming packets
+        listen_for_packets();
+        // For every packet recivied, we fork,
+        // then we make sure it's conform
+        // We then extract the data from it to make it easy to work with
+        check_header();
+        // If the sender is not in the neighbourhood, and we have 15 neighbours, we
+        // ignore the packet. Otherwise, we add him to the neighbourhood, marked as
+        // temporary.
+        update_neighbours();
+        // We then look at the differents TLVs in the packet.
+        work_with_tlvs();
+
+        time_t delay = time(NULL) + 20;
+        while(! (delay < time(NULL)){
+            // Theses functions are there for general book-keeping,and run in there own
+            // thread, being run every 20 seconds.
+            // Every 20 sec, if we have less than 5 neighbours, we ask for more peers
+            // by sending out a TLV neighbour Request at a random peer.
+            t_ask_for_more_peers();
+            // Every 20 sec, we also check for a peer that didn't emit a new message for
+            // the past 70 sec, if he's temporary, we delete him from the neighbourhood.
+            t_update_neighbours();
+            // We send out a TLV Network hash to get an ideal of the network state.
+            t_get_network_state();
+        }
+    }
+    return 0;
+}

src/node.h

@@ -0,0 +1,64 @@
+// Define constants
+
+#ifndef NODE_H
+#define NODE_H
+
+// The node ID
+#define NODE_ID 203242402519736214145149136169422092269247115186189140178187251487819615911212154252117172522111472481308026129190139512419121015210238252292031613214452118122204415160254
+
+// The number of neighbours
+// The neighbour table has 15 entries
+#define NEIGHBOUR_MAX 15
+
+/* la table de voisins, qui est indexée par adresses de socket (des paires (IP, Port)),
+ * et dont chaque entrée contient un booléen indiquant si le pair est permanent
+ * (configuré au lancement) ou transitoire, et la date de dernière réception d’un
+ * paquet de la part de ce pair ;
+*/
+typedef struct neighbour_peer {
+    struct in6_addr ip;
+    short port;
+    char is_temporary;
+    struct timeval last_seen;
+} neighbour_peer;
+
+// The strucuture to hold the messages
+/* It's a list of triplets, (Li,Si,Di)
+ * Li : The Node ID of the publisher 64 bits
+ * Si : the sequence number 16 bits
+ * Di : the data of the message 192 bytes
+*/
+
+typedef struct message {
+    long node_id_publisher;
+    short seqno;
+    char *data;
+} message;
+
+// TODO
+
+// fonctions signatures
+void listen_for_packets();
+
+void check_header();
+
+void update_neighbours();
+
+void work_with_tlvs();
+
+int validate_tlvs();
+
+// threaded functions
+
+void t_ask_for_more_peers();
+
+void t_update_neighbours();
+
+void t_get_network_state();
+
+// Helper functions
+char * hash();
+
+short * get_seq_no(short s, int n);
+
+#endif

src/parser.c

@@ -10,7 +10,8 @@ cmd_token parse_cmd() {
 	if(fgets(buf, 198, stdin) == NULL)
 		return token;
 
-	// cmd sera le premier mot rencontré et arg la suite de mots après celui ci, si les deux variables ne sont pas remplies alors il y a une erreur
+	// cmd sera le premier mot rencontré et arg la suite de mots après celui ci,
+	// si les deux variables ne sont pas remplies alors il y a une erreur
 	if(sscanf(buf, "%s %[^\t\n]", cmd, arg) != 2)
 		return token;
 

src/parser.h

@@ -1,6 +1,9 @@
 #include <stdio.h>
 #include <string.h>
 
+#ifndef PARSER_H
+#define PARSER_H
+
 typedef enum cmd_type {
 	NEIGHBOUR_REQ, NETWORK_STATE_REQ, NODE_STATE_REQ, POST, ERROR
 } cmd_type;
@@ -12,3 +15,5 @@ typedef struct cmd_token {
 
 // retourne le type de commande à exécuter
 cmd_token parse_cmd();
+
+#endif

src/test.c

@@ -1,15 +0,0 @@
-#include <stdio.h> 
-#include <stdlib.h>
-#include <unistd.h>
-
-int main() {
-	char a[1];
-	a[0] = 0;
-
-	if(fork() == 0) {
-		while(1)
-			printf("%d\n", a[0]);
-	} else {
-		a[1] = 1;
-	}
-}

src/tlv.h

@@ -3,6 +3,9 @@
 #include <stdlib.h>
 #include "parser.h"
 
+#ifndef TLV_H
+#define TLV_H
+
 // 8 octets min (struct pointer 4 octets), 1024 octets max
 typedef struct packet {
 	unsigned char magic; // 95 (si autre, ignorer)
@@ -80,7 +83,7 @@ typedef struct node_state {
 typedef struct warning {
 	unsigned char type;
 	unsigned char length;
-	char *message;
+	char message[256];
 } warning;
 
 typedef union tlv {
@@ -111,3 +114,5 @@ int build_node_hash(tlv *tlv, long node_id, short seqno, char *node_hash);
 int build_node_state_req(tlv *tlv, long node_id);
 int build_node_state(tlv *tlv, long node_id, short seqno, char *node_hash, char *data);
 int build_warning(tlv *tlv, char *message);
+
+#endif

tlv.c

@@ -1,188 +0,0 @@
-#include "tlv.h"
-
-// creer un tlv
-int build_tlv(tlv *tlv, cmd_token token) {
-	switch(token.type) {
-		case NEIGHBOUR_REQ:
-			// a remplir
-			break;
-		case NETWORK_STATE_REQ:
-			// a remplir
-			break;
-		case NODE_STATE_REQ:
-			// a remplir
-			break;
-		case POST:
-			// a remplir
-			break;
-		case ERROR:
-			printf("Wrong format, use 'req {neighbour | network state | node state}' or 'post {message}'");
-			break;
-	}
-}
-
-int build_pad1(tlv *tlv) {
-	pad1 *new = (pad1*) malloc(sizeof(pad1));
-
-	if(new == NULL)
-		return -1;
-
-	new->type = 0;
-
-	tlv->pad1 = new;
-
-	return 0;
-}
-
-int build_padn(tlv *tlv, size_t len) {
-	padn *new = (padn*) malloc(sizeof(padn));
-
-	if(new == NULL)
-		return -1;
-
-	new->type = 1;
-	new->length = len;
-	new->mbz = (char*) calloc(sizeof(char), len);
-
-	tlv->padn = new;
-
-	return 0;
-}
-
-int build_neighbour_req(tlv *tlv) {
-	neighbour_req *new = (neighbour_req*) malloc(sizeof(neighbour_req));
-
-	if(new == NULL)
-		return -1;
-
-	new->type = 2;
-	new->length = 0;
-
-	tlv->neighbour_req = new;
-
-	return 0;
-}
-
-int build_neighbour(tlv *tlv, struct in6_addr ip, short port) {
-	neighbour *new = (neighbour*) malloc(sizeof(neighbour));
-
-	if(new == NULL)
-		return -1;
-
-	new->type = 3;
-	new->length = 18;
-	new->ip = ip;
-	new->port = port;
-
-	tlv->neighbour = new;
-
-	return 0;
-}
-
-int build_network_hash(tlv *tlv, char *hash) {
-	network_hash *new = (network_hash*) malloc(sizeof(network_hash));
-
-	if(new == NULL)
-		return -1;
-
-	new->type = 4;
-	new->length = 16;
-	memcpy(new->network_hash, hash, 16);
-
-	tlv->network_hash = new;
-
-	return 0;
-}
-
-int build_network_state_req(tlv *tlv) {
-	network_state_req *new = (network_state_req*) malloc(sizeof(network_state_req));
-
-	if(new == NULL)
-		return -1;
-
-	new->type = 5;
-	new->length = 0;
-
-	tlv->network_state_req = new;
-
-	return 0;
-}
-
-int build_node_hash(tlv *tlv, long node_id, short seqno, char *hash) {
-	node_hash *new = (node_hash*) malloc(sizeof(node_hash));
-
-	if(new == NULL)
-		return -1;
-
-	new->type = 6;
-	new->length = 26;
-	new->node_id = node_id;
-	new->seqno = seqno;
-	memcpy(new->node_hash, hash, 16);
-
-	tlv->node_hash = new;
-
-	return 0;
-}
-
-int build_node_state_req(tlv *tlv, long node_id) {
-	node_state_req *new = (node_state_req*) malloc(sizeof(node_state_req));
-
-	if(new == NULL)
-		return -1;
-
-	new->type = 7;
-	new->length = 8;
-	new->node_id = node_id;
-
-	tlv->node_state_req = new;
-
-	return 0;
-}
-
-int build_node_state(tlv *tlv, long node_id, short seqno, char *node_hash, char *data) {
-	node_state *new = (node_state*) malloc(sizeof(node_state));
-	int len = strlen(data);
-
-	if(new == NULL)
-		return -1;
-
-	// en mettant cet octet à 0 on est surs de traiter un champ data de taille 192 max
-	if(len > 192) {
-		data[192] = 0;
-		len = 192;
-	}
-
-	new->type = 8;
-	new->length = 26 + len;
-	new->node_id = node_id;
-	new->seqno = seqno;
-	memcpy(new->node_hash, node_hash, 16);
-	memcpy(new->data, data, len);
-
-	tlv->node_state = new;
-
-	return 0;
-}
-
-int build_warning(tlv *tlv, char *message) {
-	warning *new = (warning*) malloc(sizeof(warning));
-	int len = strlen(message);
-
-	if(new == NULL)
-		return -1;
-
-	// en mettant cet octet à 0 on est surs de traiter un champ message de taille 256 max
-	if(len > 256) {
-		message[256] = 0;
-		len = 256;
-	}
-
-	new->type = 9;
-	new->length = len;
-	memcpy(new->message, message, len); 
-
-	tlv->warning = new;
-
-	return 0;
-}

tlv.h

@@ -1,113 +0,0 @@
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <stdlib.h>
-#include "parser.h"
-
-// 8 octets min (struct pointer 4 octets), 1024 octets max 
-typedef struct packet {
-	unsigned char magic; // 95 (si autre, ignorer)
-	unsigned char version; // 1 (si autre, ignorer)
-	short length; // 1020 max
-	char *body;
-} packet;
-
-// 1 octet
-typedef struct pad1 {
-	unsigned char type;
-} pad1;
-
-// 2 octets min, 258 octets max (unsigned char 0 -> 255)
-typedef struct padn {
-	unsigned char type;
-	unsigned char length;
-	char mbz[256];
-} padn;
-
-// 2 octets
-typedef struct neighbour_req {
-	unsigned char type;
-	unsigned char length;
-} neighbour_req;
-
-// 20 octets
-typedef struct neighbour {
-	unsigned char type;
-	unsigned char length;
-	struct in6_addr ip;
-	short port;
-} neighbour;
-
-// 18 octets
-typedef struct network_hash {
-	unsigned char type;
-	unsigned char length;
-	char network_hash[16];
-} network_hash;
-
-// 2 octets
-typedef struct network_state_req {
-	unsigned char type;
-	unsigned char length;
-} network_state_req;
-
-// 28 octets
-typedef struct node_hash {
-	unsigned char type;
-	unsigned char length;
-	long node_id;
-	short seqno;
-	char node_hash[16];
-} node_hash;
-
-// 10 octets
-typedef struct node_state_req {
-	unsigned char type;
-	unsigned char length;
-	long node_id;
-} node_state_req;
-
-// 28 octets min, 220 octets max (data 0 -> 192)
-typedef struct node_state {
-	unsigned char type;
-	unsigned char length;
-	long node_id;
-	short seqno;
-	char node_hash[16];
-	char data[192];
-} node_state;
-
-// 2 octets min, 258 ocets max (unsigned char 0 -> 255)
-typedef struct warning {
-	unsigned char type;
-	unsigned char length;
-	char *message;
-} warning;
-
-typedef union tlv {
-	pad1 *pad1;
-	padn *padn;
-	neighbour_req *neighbour_req;
-	neighbour *neighbour;
-	network_hash *network_hash;
-	network_state_req *network_state_req;
-	node_hash *node_hash;
-	node_state_req *node_state_req;
-	node_state *node_state;
-	warning *warning;
-} tlv;
-
-
-// creer un tlv
-int build_tlv(tlv *tlv, cmd_token token);
-
-// creer un tlv specifique
-int build_pad1(tlv *tlv);
-int build_padn(tlv *tlv, size_t len);
-int build_neighbour_req(tlv *tlv);
-int build_neighbour(tlv *tlv, struct in6_addr ip, short seqno);
-int build_network_hash(tlv *tlv, char *network_hash);
-int build_network_state_req(tlv *tlv);
-int build_node_hash(tlv *tlv, long node_id, short seqno, char *node_hash);
-int build_node_state_req(tlv *tlv, long node_id);
-int build_node_state(tlv *tlv, long node_id, short seqno, char *node_hash, char *data);
-int build_warning(tlv *tlv, char *message);