Added tlv_list and check_header

src/node.c

@@ -1,15 +1,124 @@
 // This is the main file of the Dazibao project. It represents the node, and
 // handles all of the main logic, including the network connexions.
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <string.h>
+
+#include "tlv.h"
+#include "node.h"
 
 
-// Will return a packet when we receive one that's valid.
-packet listen_for_packets(){
+// For every packet recivied,
+// then we make sure it's conform
+// We then extract the data from it to make it easy to work with
+int check_header(char * req[], int buffer_size, packet * packet_to_return){
 
+    packet * packet_to_return = (packet*) req;
+
+    // We need to check a few things ;
+    // The first byte must be worth 95,
+    if (packet_to_return->magic != 95) {
+        perror(">> The magic number of the packet is no good.");
+        return -1;
+    }
+
+    // The second byte must be worth 1,
+    if (packet_to_return->version != 1) {
+        perror(">> The version number of the packet is no good.");
+        return -1;
+    }
+
+    if (packet_to_return.length + 4 > buffer_size  ) {
+        perror(">> The packet length is bigger than the UDP datagram, which is not possible with the current laws of physics.");
+        return -1;
+    }
+
+    return 0;
 }
 
+// We listen forever for new paquets;
+void listen_for_packets(){
+
+    // Create new socket for UDP
+    int s = socket(AF_INET6, SOCK_DGRAM, 0);
+
+    if(s < 0) {
+        perror(">> Error, cannot create socket.");
+        perror(">> Exiting...")
+        exit(1);
+    }
+
+    struct sockaddr_in6 server;
+    memset(&server, 0, sizeof(server));
+
+    server.sin6_family = AF_INET6;
+    server.sin6_port = htons(LISTEN_PORT);
+    int rc = bind(s, (struct sockaddr*)&server, sizeof(server));
+    if(rc < 0) {
+        perror(">> Error, cannot bind socket to choosen port.");
+        perror(">> Exiting...")
+        exit(1);
+    }
+
+    // A paquet has at most a length of 1024 bytes
+    char req[1024];
+    struct sockaddr_in6 client;
+    struct iovec io = { .iov_len = 1024, .iov_base = req };
+    struct msghdr msg_to_receive = {
+        .msg_name = &client,
+        .msg_namelen = sizeof(client),
+        .msg_iov = &io,
+        .msg_iovlen = 1
+    };
+    while(1){
+        memset(req, '\0', 1024);
+
+        struct sockaddr_in6 client;
+        unsigned int client_len = sizeof(client);
+
+        rc = recvmsg(s, &msg_to_receive, 0);
+        if(rc < 0) {
+            perror(">> Error while receiving a new datagram.");
+            perror(">> Ignoring, continuing...")
+            continue;
+        }
+
+        printf(">> New paquet received :\n");
+        printf("%s\n", req);
+
+        // We verify the received packet is well formated,
+        // and we return it in the struct designed to work with it.
+        struct packet * formated_rec_datagram;
+        if(check_header(&req, 1024, formated_rec_datagram) < 0){
+            perror(">> Error while checking the header, aborting this packet, by choice, and conviction.");
+            continue;
+        }
+
+        struct tlv_list received_tlvs = validate_tlvs(formated_rec_datagram);
+    }
+}
+
+
+
+
+// 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.
+int update_neighbours(){
+
+};
+
+// We then look at the differents TLVs in the packet.
+void work_with_tlvs(){
+
+};
+
 // 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){
+tlv_list validate_tlvs(packet packet_to_validate){
 
 }
 
@@ -54,7 +163,7 @@ void work_with_tlvs(struct tlvs_list receivied_tlvs){
 
 int main(int argc, char const *argv[]) {
     int continue = 1;
-    
+
     while(continue){
 
         // We create the neighbourhood table
@@ -65,17 +174,8 @@ int main(int argc, char const *argv[]) {
 
         // 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();
 
+        // This is in it's own fork.
         time_t delay = time(NULL) + 20;
         while(! (delay < time(NULL)){
             // Theses functions are there for general book-keeping,and run in there own

src/node.h

@@ -3,6 +3,11 @@
 #ifndef NODE_H
 #define NODE_H
 
+#include "tlv.h"
+
+// On which port do we listen to
+#define LISTEN_PORT 1212
+
 // The node ID
 #define NODE_ID 203242402519736214145149136169422092269247115186189140178187251487819615911212154252117172522111472481308026129190139512419121015210238252292031613214452118122204415160254
 
@@ -40,14 +45,14 @@ typedef struct message {
 // fonctions signatures
 void listen_for_packets();
 
-void check_header();
+int check_header(char * received_datagram[], int len, packet pack);
 
-void update_neighbours();
+int validate_tlvs(packet * pack, tlv_list * tlv_l);
+
+int update_neighbours();
 
 void work_with_tlvs();
 
-int validate_tlvs();
-
 // threaded functions
 
 void t_ask_for_more_peers();

src/tlv.h

@@ -99,6 +99,11 @@ typedef union tlv {
 	warning *warning;
 } tlv;
 
+typedef struct tlv_list {
+		union tlv one_tlv;
+		struct tlv_list * next;
+} tlv_list;
+
 
 // creer un tlv
 int build_tlv(tlv *tlv, cmd_token token);