:yay:

A3/python/peer/peer.py

@@ -260,7 +260,9 @@ class CascadePeerServe(socketserver.StreamRequestHandler):
                 resp.extend(struct.pack('!Q', block.length))
                 resp.extend(data)
 
+                print("sending")
                 self.request.sendall(resp)
+                print("sent")
 
     def reporterror(self, code: int, msg: str) -> None:
         msgdata = bytes(msg, 'utf-8')

A3/python/tracker/tracker.py

@@ -48,7 +48,7 @@ class TrackerServer(socketserver.StreamRequestHandler):
             if datalen != CMD_LENGTH:
                 self.respond_error(f'Data for command=1 must be of length {CMD_LENGTH}, got {datalen}')
                 return
-                
+
             data = self.request.recv(CMD_LENGTH)
             if len(data) != CMD_LENGTH:
                 self.respond_error(f'Data from socket had length {len(data)}, expected {CMD_LENGTH}')
@@ -78,7 +78,7 @@ class TrackerServer(socketserver.StreamRequestHandler):
                 # Avoid peers registering as good peers without approval
                 if is_good_client(data[32:36], self.goodips):
                     if str(ipaddress.IPv4Address(data[32:36])) == self.client_address[0]:
-                        print("Registering a good client")
+                        print(f"Registering a good client at {ipaddress.IPv4Address(data[32:36])}:{int.from_bytes(data[36:38],'big')}")
                     else:
                         self.respond_error(f'The IP reported to the tracker ({".".join([str(x) for x in data[32:36]])}) is a reserved IP')
                         return
@@ -88,6 +88,7 @@ class TrackerServer(socketserver.StreamRequestHandler):
                 with self.lock:
                     self.active_clients[hashhex][ipportkey] = int(time.time())
 
+            print(f"Reporting clients to {ipaddress.IPv4Address(data[32:36])}:{int.from_bytes(data[36:38],'big')}")
             self.report_clients(hash.hex(), ipportkey)
 
         else:

A3/src/cascade.c

@@ -139,7 +139,7 @@ void download_only_peer(char *cascade_file)
     {
         if (peers[i].good)
         {
-            peer = peers[i];
+            peer = (peers[i]);
         }
     }
 
@@ -147,6 +147,7 @@ void download_only_peer(char *cascade_file)
     {
         get_block(queue[i], peer, hash_buf, output_file);
     }
+    printf("\n");
 
     free_resources();
 }
@@ -253,7 +254,7 @@ csc_file_t* csc_parse_file(const char* sourcefile, const char* destination)
     casc_file_data->blockcount = 1 + floor(
         (casc_file_data->targetsize - 1.0)/casc_file_data->blocksize
     );
-    casc_file_data->trailblocksize = (casc_file_data->blockcount * casc_file_data->blocksize) - casc_file_data->targetsize;
+    casc_file_data->trailblocksize = casc_file_data->targetsize - ((casc_file_data->blockcount - 1) * casc_file_data->blocksize);
 
     csc_block_t* block_list = malloc(
         sizeof(csc_block_t) * casc_file_data->blockcount
@@ -360,20 +361,75 @@ void get_block(csc_block_t* block, csc_peer_t peer, unsigned char* hash, char* o
 {
     printf("Attempting to get block %d from %s:%s for %s\n", block->index, peer.ip, peer.port, output_file);
 
+    int buffer_size;
+    if (block->length + PEER_RESPONSE_HEADER_SIZE > MAX_LINE) {
+        buffer_size = block->length + PEER_RESPONSE_HEADER_SIZE;
+    } else {
+        buffer_size = MAX_LINE;
+    }
+    printf("%i\n", buffer_size);
     rio_t rio;
-    char rio_buf[MAX_LINE];
+    char rio_buf[buffer_size];
     int peer_socket;
+    peer_socket = Open_clientfd(peer.ip, peer.port);
+    Rio_readinitb(&rio, peer_socket);
 
-    /*
+    struct ClientRequest request;
-    TODO Request a block from a peer
+    memcpy(request.protocol, "CASCADE1", 8);
+    for (int i = 0;i<16;i++) {
+        request.reserved[i] = 0;
+    }
+    request.block_num = be64toh(block->index);
+    strncpy(request.hash, hash, 32);
 
-    HINT: Remember that integers sent over a network in TCP are done so in network byte order (big-endian) and
+    memcpy(rio_buf, &request, PEER_REQUEST_HEADER_SIZE);
-    will need to be converted to a more useful format.
+    Rio_writen(peer_socket, rio_buf, PEER_REQUEST_HEADER_SIZE);
 
-    HINT: Remember to check that the data you have recieved is the data you expect. You can check this as you
+    Rio_readnb(&rio, rio_buf, buffer_size);
-    should already have a hash of block in block->hash, and you can get the hash of the data you just read by
+
-    using the function 'get_data_sha'
+    char reply_header[PEER_RESPONSE_HEADER_SIZE];
-    */
+    memcpy(reply_header, rio_buf, PEER_RESPONSE_HEADER_SIZE);
+
+    uint64_t msglen = be64toh(*((unsigned long long*)&reply_header[1]));
+
+    if (msglen == 0)
+    {
+        Close(peer_socket);
+        return 0;
+    }
+
+    if (reply_header[0] != 0)
+    {
+        char* error_buf = malloc(msglen + 1);
+        if (error_buf == NULL)
+        {
+            printf("Tracker error %d and out-of-memory reading error\n", reply_header[0]);
+            Close(peer_socket);
+            return NULL;
+        }
+        memset(error_buf, 0, msglen + 1);
+        memcpy(error_buf, &rio_buf[PEER_RESPONSE_HEADER_SIZE], msglen);
+        printf("Peer gave error: %d - %s\n", reply_header[0], error_buf);
+        free(error_buf);
+        Close(peer_socket);
+        return NULL;
+    }
+
+    unsigned char block_data[msglen];
+    memcpy(block_data,&rio_buf[PEER_RESPONSE_HEADER_SIZE],msglen);
+
+    uint8_t shabuffer[SHA256_HASH_SIZE];
+
+    SHA256_CTX shactx;
+    sha256_init(&shactx);
+    sha256_update(&shactx, block_data, msglen);
+    sha256_final(&shactx, &shabuffer);
+
+    if (memcmp(shabuffer, (&block->hash)->x, SHA256_HASH_SIZE) != 0) {
+        printf("Not the same hash\n");
+        Close(peer_socket);
+        return NULL;
+    }
 
     FILE* fp = fopen(output_file, "rb+");
     if (fp == 0)
@@ -383,15 +439,10 @@ void get_block(csc_block_t* block, csc_peer_t peer, unsigned char* hash, char* o
         return;
     }
 
-    /*
+    fseek(fp, block->offset, SEEK_SET);
-    TODO Write the block into the data file
+    fputs(block_data,fp);
 
-    HINT: You can write a block to a specific index using the fseek(...) function. Check the documentation
+    printf("Got block %d. Wrote from %d to %d\n", block->index, block->offset, block->offset+msglen-1);
-    online for details on how this work and what it does
-    */
-    int write_count;
-
-    printf("Got block %d. Wrote from %d to %d\n", block->index, block->offset, block->offset+write_count-1);
     Close(peer_socket);
     fclose(fp);
 }
@@ -420,12 +471,12 @@ int get_peers_list(csc_peer_t** peers, uint8_t hash[32])
     struct RequestBody request_body;
     strncpy(request_body.hash, hash, 32);
     inet_aton(my_ip, &request_body.ip);
-    request_body.port = atol(my_port);
+    request_body.port = be16toh(atol(my_port));
     memcpy(&rio_buf[HEADER_SIZE], &request_body, BODY_SIZE);
 
     Rio_writen(tracker_socket, rio_buf, MESSAGE_SIZE);
 
-    Rio_readnb(&rio, rio_buf, MAXLINE);
+    Rio_readnb(&rio, rio_buf, MAX_LINE);
 
     char reply_header[REPLY_HEADER_SIZE];
     memcpy(reply_header, rio_buf, REPLY_HEADER_SIZE);
@@ -461,7 +512,7 @@ int get_peers_list(csc_peer_t** peers, uint8_t hash[32])
         return NULL;
     }
     int peercount = msglen/12;
-    peers = malloc(peercount * sizeof(csc_peer_t));
+    *peers = malloc(peercount * sizeof(csc_peer_t));
 
     for (int i = 0;i<peercount;i++) {
         csc_peer_t peer;
@@ -469,8 +520,9 @@ int get_peers_list(csc_peer_t** peers, uint8_t hash[32])
         struct in_addr ip = {};
         sprintf(peer.ip, "%u.%u.%u.%u", peer_data[0], peer_data[1], peer_data[2], peer_data[3]);
         sprintf(peer.port, "%u", be16toh(*((uint16_t*)&peer_data[4])));
-    }
 
+        (*peers)[i] = peer;
+    }
     Close(tracker_socket);
     return peercount;
 }

A3/src/cascade.h

@@ -32,7 +32,7 @@ struct RequestBody
 struct ClientRequest
 {
     char protocol[8];
-    char reserved[12];
+    char reserved[16];
     uint64_t block_num;
     uint8_t hash[32];
 };

A3/src/csapp.c

@@ -859,7 +859,7 @@ ssize_t rio_readnb(rio_t *rp, void *usrbuf, size_t n)
 
     while (nleft > 0) {
         if ((nread = rio_read(rp, bufp, nleft)) < 0)
-                return -1;          /* errno set by read() */
+            return -1;          /* errno set by read() */
         else if (nread == 0)
             break;              /* EOF */
         nleft -= nread;