1 files changed, 56 insertions, 14 deletions

diff --git a/src/dht.c b/src/dht.c
index e787203..b1b1fa4 100644
--- a/src/dht.c
+++ b/src/dht.c
@@ -212,6 +212,7 @@ struct dht {
 	unsigned torrents_max; /**< max number of torrents that we are allowed to store */
 	unsigned peers_max; /**< max number of peers that we are allowed to store */
 	struct torrent * last_torrent; /**< to quickly go to the end of the doubly linked list of torrents is helpful when reaching torrents_max and needing to pop oldest */
+	unsigned peers_per_torrent_max; /**< max number of peers to store per torrent - applies to ->type and !->type torrents */
 };
 
 /**
@@ -244,6 +245,9 @@ struct dht * dht_init (const struct bencoding * c) {
 	d->buckets = bucket_init();
 	d->buckets6 = bucket_init();
 	d->possible_torrent = &possible_torrent;
+	d->torrents_max = UINT_MAX; // this is hardcore - so many torrents makes LL traversal too slow
+	d->peers_max UINT_MAX; // there's no way there even are this many peers on the entire network at a time xDDDDDDDDDDD
+	d->peers_per_torrent_max = UINT_MAX;
 	errno = 0;
 	if (!d)
 		return NULL;
@@ -366,7 +370,7 @@ struct bencoding * persistent (const struct dht * d) {
 void token (const struct dht * d, unsigned * t, const char * addr) {
 	struct AES_ctx aes;
 	memcpy(t, addr, 16);
-	AES_init_ctx(&aes, dht->secret);
+	AES_init_ctx(&aes, d->secret);
 	AES_ECB_encrypt(&aes, t);
 }
 
@@ -545,6 +549,8 @@ void split (struct bucket * b) {
 
 void replied (const struct dht * d, const unsigned char * id, const struct sockaddr_in6 * addr) {
 	struct bucket * b = d->buckets;
+	if (family(addr->sin6_addr.s6_addr) == AF_INET6)
+		b = d->buckets6;
 	struct node * n;
 	struct node * found = find(id, &b, &n);
 	if (found) {
@@ -600,7 +606,7 @@ void ping_node (const struct dht * d, const struct sockaddr_in6 * a) {
 		target[19] &= 0xFE;	// our ID but K ids around it
 	else
 		target[19] |= 1;
-	find_node(d, a, target);
+	find_node(d, a, target, NULL);
 }
 
 /**
@@ -609,15 +615,18 @@ void ping_node (const struct dht * d, const struct sockaddr_in6 * a) {
  * @param d	[in]	handle
  * @param a	[in]	address of the remote node
  * @param query	[in]	20 byte id we are querying
+ * @param t	[in]	token bencoding element (t key in dict). if NULL, a static token will be sent. ->key must be set. memory ownership is transfered away from the caller and the object is freed by this function.
  */
 
-void find_node (const struct dht * d, const struct sockaddr_in6 * a, const unsigned char * query) {
+void find_node (const struct dht * d, const struct sockaddr_in6 * a, const unsigned char * query, struct bencoding * t) {
 	struct bencoding * b = calloc(1, sizeof *b);
 	b->type = dict;
-	struct bencoding * t = bstr(strdup("t@_a.si"));
-	t->key = bstr(strdup("t"));
-	t->value[2] = '4';
-	t->type = string;
+	if (!t) {
+		t = bstr(strdup("t@_a.si"));
+		t->key = bstr(strdup("t"));
+		t->value[2] = '4';
+		t->type = string;
+	}
 	binsert(b, t);
 	struct bencoding * y = bstr(strdup("q"));
 	t->key = bstr(strdup("y"));
@@ -753,7 +762,7 @@ int bucket_good (const struct dht * d, const struct bucket * b) {
 void potential_node (const struct dht * d, const struct sockaddr_in6 * a, const unsigned char * id) {
 	struct bucket * bucket = d->buckets;
 	if (family(a->sin6_addr.s6_addr) == AF_INET6)
-		bucket = b->buckets6;
+		bucket = d->buckets6;
 	if (find(id, &bucket, NULL))
 		return;
 	if (!bucket_good(bucket));
@@ -859,11 +868,19 @@ void remove_torrent (struct dht * d, struct torrent * t) {
 
 struct peer * add_peer (struct dht * d, struct torrent * t, struct peer * p) {
 	struct peer * peer = torrent->peers;
-	while (peer)
+	unsigned i = 0;
+	while (peer) {
 		if (!memcmp(&peer->addr, &addr, sizeof addr)) {
-			free(p);
+			peer_free(p);
 			return peer;
 		}
+		if (peer->next && !peer->next->next)
+			if (++i >= d->peers_per_torrent_max) {
+				d->peers--;
+				free_peer(peer->next);
+				peer->next = NULL;
+			}
+	}
 	peer->next = torrent->peers;
 	torrent->peers = peer;
 	d->peers++;
@@ -1001,6 +1018,7 @@ void handle (struct dht * d, char * pkt, int len, struct sockaddr_in6 addr) {
 					if (family(addr.sin6_addr.s6_addr) == AF_INET6 || bval(bpath("a/want"), "v6")) {
 						binsert(response, nodes(d, target->value, AF_INET6));
 					sendb(d, response, &addr, addrlen);
+					free_bencoding(response);
 					break;
 				case 'G': // get_peers
 				case 'g':
@@ -1047,6 +1065,7 @@ void handle (struct dht * d, char * pkt, int len, struct sockaddr_in6 addr) {
 					token(d, (tok->value = malloc((tok->valuelen = 16))), addr.sin6_addr.s6_addr);
 					binsert(r, tok);
 					sendb(d, response, &addr, addrlen);
+					free_bencoding(response);
 					break;
 				case 'A': // announce
 				case 'a':
@@ -1071,7 +1090,6 @@ void handle (struct dht * d, char * pkt, int len, struct sockaddr_in6 addr) {
 					struct bencoding * y = bstr(strdup("r"));
 					y->key = bstr(strdup("y"));
 					binsert(response, y);
-					sendb(response); // first we send confirmation, then we store
 					struct torrent * torrent = calloc(1, sizeof *torrent);
 					memcpy(torrent->hash, hash->value, 20);
 					torrent = add_torrent(d, torrent);
@@ -1080,20 +1098,44 @@ void handle (struct dht * d, char * pkt, int len, struct sockaddr_in6 addr) {
 					if (bpath(b, "a/port") && !bpath(b, "a/implied_port") || !bpath(b, "a/implied_port")->intvalue)
 						peer->addr.sin6_port = htons(bpath(b, "a/port")->intvalue);
 					add_peer(d, torrent, peer);
+					sendb(response);
+					free_bencoding(response);
 					break;
 				default: // see NOTE01
 					int len = b2json_length(b);
 					char json[len+1];
 					b2json(json, b);
 					json[len] = '\0';
-					L(dht->log, "%s sent an unknown query type: %s");
+					L(d->log, "%s sent an unknown query type: %s");
 					break;
 			}
 			break;
 		case 'R':
 		case 'r':
-			// TODO
-			break;
+			struct bencoding * rid = bpath(b, "r/id");
+			if (rid && rid->type & string && rid->valuelen == 20)
+				replied(d, rid->value, &addr); // since here I'm only really interested about nodes and values
+			struct bencoding * t = bpath(b, "t");
+			if (!(t && t->type & string && t->valuelen == 20))
+				break;
+			if (!(torrent = find_torrent(d, t->value)))
+				break;
+			if (!torrent->type) // yeet, l33t haxx0r tried to announce a torrent by sending a crafted response to a ficticios get_peers query
+				break; // this could enable the DHT node to be used as a DDoS spreader. uninterested torrents can't be updated this way
+			bforeach (bpath(b, "r/values"), p) {
+				if (!(p->type & string) || (p->valuelen != 6 && p->valuelen != 18))
+					break;
+				struct peer * peer = calloc(1, sizeof *peer);
+				memcpy(peer->addr.sin6_addr, "\0\0\0\0\0\0\0\0\0\0\0\0\xFF\xFF\xFF\xFF", 12);
+				peer->addr.sin6_port = *((uint16_t *) (peer->value + peer->valuelen-2));
+				memcpy(peer->addr.sin6_addr+(p->valuelen == 6 ? 8 : 0), p->valuelen == 6 ? 4 : 16);
+				add_peer(d, torrent, peer);
+			}
+			bforeach (bpath(b, "r/nodes" /* haha subreddit */), n) {
+				if (!(n->type & string) || (n->valuelen != 4+2+20 && n->valuelen != 16+2+20))
+					break;
+				// TODO nodes and nodes6
+			}
 		case 'E':
 		case 'e':
 			struct bdecoding * e = bpath(b, "e");