Merge branch 'dev-nelson' into 'master'

Add headers and node file

See merge request perdriau/dazibao!1

Notes.md

@@ -1 +1,9 @@
 # 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

src/node.c

@@ -0,0 +1,90 @@
+// 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(){
+
+}
+
+int validate_tlvs(union tlv tlv_to_validate){
+    // We need to make sure the TLV announces a length that will no go onto
+    // another tlv, as we might end up reading bullshit.
+}
+
+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, is 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[]) {
+
+    while(CONTINUE){
+
+        // We create the neighbourhood table
+        // 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 +1,26 @@
+// Define constants
+
+
+// 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);