diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/dht.c | 127 | ||||
| -rw-r--r-- | src/main.c | 47 |
2 files changed, 125 insertions, 49 deletions
@@ -84,6 +84,8 @@ struct node { time_t last_received; /**< time when I received the last packet from it */ time_t last_sent; /**< time when I sent the last query to it. not incremented if it has unanswered queries. */ struct node * next; +#define SERVER_ERRORS_BAD 15 + unsigned server_errors; /**< number of server errors, set node grade to bad if more than SERVER_ERRORS_BAD. reset when replied() */ }; /** @@ -147,6 +149,8 @@ char * node_grade_str (enum node_grade g) { #define QUESTIONABLE_AFTER (15*60) enum node_grade node_grade (const struct node * n) { + if (n->server_errors > SERVER_ERRORS_BAD) + return bad; if (n->last_received + QUESTIONABLE_AFTER < seconds()) { if (n->last_sent + 60 < seconds() && n->unanswered > 1) return bad; @@ -236,7 +240,8 @@ enum flags { goodmeta = 1 << 3, /**< peer gave us good metadata that is currently stored in the torrent */ badmeta = 1 << 4, /**< peer gave us bogus metadata that does not match it's hash */ unreachable = 1 << 5, /**< pear unreachable - timed out */ - requested = 1 << 6 /**< because choking is unimplemented, packets are sent like with TFTP, a request is sent only when a reply is received */ + requested = 1 << 6, /**< because choking is unimplemented, packets are sent like with TFTP, a request is sent only when a reply is received */ + protocolerror = 1 << 7 /**< I don't understand you my g */ }; /** @@ -278,7 +283,7 @@ void peer_print (FILE * s, const struct peer * p) { char remote[INET6_ADDRSTRLEN + 64]; if (!inet_ntop(p->addr.sin6_family, p->addr.sin6_addr.s6_addr, remote, INET6_ADDRSTRLEN+7)) snprintf(remote, sizeof remote, "(inet_ntop: %s)", strerror(errno)); - fprintf(s, "%s/%d %s%s%s%s%s%s", remote, ntohs(p->addr.sin6_port), p->flags & nometasupport ? " nometasupport" : "", p->flags & nometa ? " nometa" : "", p->flags & goodmeta ? " goodmeta" : "", p->flags & badmeta ? " badmeta" : "", p->flags & unreachable ? " unreachable" : "", p->flags & requested ? " requested" : ""); + fprintf(s, "%s/%d %s%s%s%s%s%s%s", remote, ntohs(p->addr.sin6_port), p->flags & nometasupport ? " nometasupport" : "", p->flags & nometa ? " nometa" : "", p->flags & goodmeta ? " goodmeta" : "", p->flags & badmeta ? " badmeta" : "", p->flags & unreachable ? " unreachable" : "", p->flags & requested ? " requested" : "", p->flags & protocolerror ? " protocolerror" : ""); } /** @@ -337,6 +342,7 @@ struct torrent { unsigned char * packet; /**< packet being constructed from tcp for info torrents, 32727 bytes */ int recvd; /**< length of received data for current packet */ char * software; /**< can be read from disconnection() - software string client sent, may be NULL */ + time_t ttl; /**< if nonzero, torrent will get his ->type cleared after this seconds() timestamp. set to seconds()+512 for example */ }; /** @@ -522,6 +528,10 @@ struct dht { #define PINGS_CAP 256 /**< capacity of circular buffer, one element is ~28 bytes, so this is 7168 B */ struct sockaddr_in6 pings[PINGS_CAP]; /**< circular buffer of recent pings */ unsigned periods; /**< number of times periodic() was called */ + unsigned rxqp; + unsigned txqp; + unsigned rxrp; + unsigned txrp; }; /** @@ -601,6 +611,13 @@ void possible_torrent (struct dht * d __attribute__((unused)), const unsigned ch */ void sendb (struct dht * d, struct bencoding * b, const struct sockaddr_in6 * a) { + struct bencoding * y = bpath(b, "y"); + if (y && y->type & string && y->valuelen >= 1) { + if (y->value[0] == 'r') + d->txrp++; + else + d->txqp++; + } char remote[INET6_ADDRSTRLEN + 64]; if (!inet_ntop(a->sin6_family, &a->sin6_addr, remote, INET6_ADDRSTRLEN+7)) snprintf(remote, sizeof remote, "(inet_ntop: %s)", strerror(errno)); @@ -1129,7 +1146,7 @@ unsigned int distance (const unsigned char * a, const unsigned char * b) { } /** - * returns 1 if bucket is perfect, meaning it is fresh, has K nodes, and all nodes are good. bucket that contains id is almost never perfect, as it can usually be split into smaller buckets, that's why param d is required to get own id + * returns 1 if bucket is perfect, meaning it is fresh, has K nodes, and no node is bad. bucket that contains id is almost never perfect, as it can usually be split into smaller buckets, that's why param d is required to get own id * * if d is NULL, it's not checked whether we fall into the bucket and whether it could be split * @@ -1137,9 +1154,9 @@ unsigned int distance (const unsigned char * a, const unsigned char * b) { * @param b [in] the bucket */ -int bucket_good (const struct dht * d, const struct bucket * b) { +int bucket_grade (const struct dht * d, const struct bucket * b) { if (d) { - if (!bucket_good(NULL, b)) + if (!bucket_grade(NULL, b)) return 0; if (in_bucket(d->id, b)) { struct node * n = b->nodes; @@ -1156,7 +1173,7 @@ int bucket_good (const struct dht * d, const struct bucket * b) { return 0; struct node * n = b->nodes; if (n) { - if (node_grade(n) != good) + if (node_grade(n) == bad) return 0; n = n->next; } @@ -1179,8 +1196,6 @@ int bucket_good (const struct dht * d, const struct bucket * b) { */ void replied (const struct dht * d, const unsigned char * id, const struct sockaddr_in6 * addr) { - if (!memcmp(d->id, id, 20)) // WE COULDN'T'VE POSSIBLY REPLIED TO OURSELVES! - return; struct bucket * b = d->buckets; if (family(addr->sin6_addr.s6_addr) == AF_INET6) b = d->buckets6; @@ -1188,10 +1203,12 @@ void replied (const struct dht * d, const unsigned char * id, const struct socka struct node * found = find(id, &b, &n); if (found) { found->last_received = seconds(); - found->unanswered = 0; + found->server_errors = found->unanswered = 0; return; } - if (bucket_good(d, b)) + if (!memcmp(d->id, id, 15)) // WE COULDN'T'VE POSSIBLY REPLIED TO OURSELVES - or sybil attack + return; + if (bucket_grade(d, b)) return; struct node * node = node_init(); memcpy(&node->addr, addr, sizeof *addr); @@ -1252,14 +1269,14 @@ void replied (const struct dht * d, const unsigned char * id, const struct socka void potential_node (struct dht * d, const struct sockaddr_in6 * a, const unsigned char * id) { if (!a->sin6_port) return; // sorry, I can't send to port 0. this is a mistake or a malicious node - if (!memcmp(d->id, id, 20)) // we are not a potential node of ourselves + if (!memcmp(d->id, id, 15)) // we are not a potential node of ourselves, if 15 bytes are same : sybil return; struct bucket * bucket = d->buckets; if (family(a->sin6_addr.s6_addr) == AF_INET6) bucket = d->buckets6; if (find(id, &bucket, NULL)) return; - if (!bucket_good(d, bucket)) + if (!bucket_grade(d, bucket)) ping_node(d, a); } @@ -1323,7 +1340,7 @@ void remove_torrent (struct dht * d, struct torrent * t) { void oom (struct dht * d) { struct torrent * drop = d->last_torrent; - while (drop && drop->type) + while (drop && (drop->type || drop->dl)) drop = drop->prev; remove_torrent(d, drop); } @@ -1345,6 +1362,8 @@ struct torrent * add_torrent (struct dht * d, struct torrent * t) { torrent_free(t); return found; } + if (d->torrents_num >= d->torrents_max) + oom(d); if (d->torrents) d->torrents->prev = t; else @@ -1359,8 +1378,6 @@ struct torrent * add_torrent (struct dht * d, struct torrent * t) { else memcpy(d->sample+20*(rand() % 3000), t->hash, 20); #endif - if (d->torrents_num >= d->torrents_max) - oom(d); return t; } @@ -1385,12 +1402,14 @@ struct peer * add_peer (struct dht * d, struct torrent * t, struct peer * p) { unsigned l = 0; while (*peer) { l++; - if (!memcmp(&(*peer)->addr, &p->addr, sizeof p->addr)) { + if (!memcmp((*peer)->addr.sin6_addr.s6_addr, p->addr.sin6_addr.s6_addr, 16)) { // ignore multiple peers on same port peer_free(p); return *peer; } if (*peer != t->dl) nondl = peer; + else // dls are holy + goto c; if ((*peer)->flags & badmeta) bad = peer; if ((*peer)->flags & nometasupport && !(bad && (*bad) && (*bad)->flags & badmeta)) @@ -1404,6 +1423,7 @@ struct peer * add_peer (struct dht * d, struct torrent * t, struct peer * p) { *peer = next; continue; } + c: peer = &(*peer)->next; } if (bad && l > d->peers_per_torrent_max) { @@ -1592,9 +1612,10 @@ void compact (struct dht * d, const char * value, int len, struct torrent * t) { memcpy(addr.sin6_addr.s6_addr+(len == 4+2+20 ? 12 : 0), value + 20, len == 4+2+20 ? 4 : 16); #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wpointer-sign" - potential_node(d, &addr, value); // NOTE02 at the beginning, a lot of packets will be sent, since every reply of potential_node will generate K replies. naively this would generate an exponentially increasing number of packets, in increasing powers of 8 (8**n). to prevent an absolute resource hog, this is only done when node would be useful and would contribute to the routing table if (t) potential_torrent_node(d, t, &addr, value); + else + potential_node(d, &addr, value); // NOTE02 at the beginning, a lot of packets will be sent, since every reply of potential_node will generate K replies. naively this would generate an exponentially increasing number of packets, in increasing powers of 8 (8**n). to prevent an absolute resource hog, this is only done when node would be useful and would contribute to the routing table #pragma GCC diagnostic pop } @@ -1736,6 +1757,12 @@ void handle (struct dht * d, char * pkt, int len, struct sockaddr_in6 addr) { L(incoming_dht, d, "handle(%s): %s", remote, out); } struct bencoding * y = bpath(b, "y"); + if (y && y->type & string && y->valuelen >= 1) { + if (y->value[0] == 'r') + d->rxrp++; + else + d->rxqp++; + } char * msg_type = ""; if (y && y->type & string) msg_type = y->value; @@ -1864,18 +1891,16 @@ void handle (struct dht * d, char * pkt, int len, struct sockaddr_in6 addr) { struct torrent * torrent = find_torrent(d, hash->value, 20); d->possible_torrent(d, hash->value, torrent); #pragma GCC diagnostic pop - unsigned i = 0; + unsigned i = 8; if (torrent) { struct peer * peer = torrent->peers; struct bencoding * values = calloc(1, sizeof *values); values->type = list; - while (peer) { // TODO implement peer preference: prefer sending peers that responded to us + while (i-- && peer) { // TODO implement peer preference: prefer sending peers that responded to us if (family(peer->addr.sin6_addr.s6_addr) != family(addr.sin6_addr.s6_addr)) // possible goto c; - if (peer->flags & unreachable) + if (peer->flags & (unreachable || protocolerror)) goto c; - if (i++ > K) - break; struct bencoding * value = calloc(1, sizeof *value); memcpy((value->value = malloc((value->valuelen = ADDRLEN(family(peer->addr.sin6_addr.s6_addr))+2))), peer->addr.sin6_addr.s6_addr, ADDRLEN(family(peer->addr.sin6_addr.s6_addr))); memcpy(value->value+ADDRLEN(family(peer->addr.sin6_addr.s6_addr)), &peer->addr.sin6_port, 2); @@ -1988,10 +2013,10 @@ void handle (struct dht * d, char * pkt, int len, struct sockaddr_in6 addr) { struct bencoding * nodes = bpath(b, "r/nodes"); struct bencoding * nodes6 = bpath(b, "r/nodes6"); if (nodes && nodes->type & string && !(nodes->valuelen % 26)) - for (unsigned i = 0; i < MIN(nodes->valuelen, K); i += 26) + for (unsigned i = 0; i < MIN(nodes->valuelen, K*26); i += 26) compact(d, nodes->value+i, 26, torrent); if (nodes6 && nodes6->type & string && !(nodes6->valuelen % 38)) - for (unsigned i = 0; i < MIN(nodes6->valuelen, K); i += 38) + for (unsigned i = 0; i < MIN(nodes6->valuelen, K*38); i += 38) compact(d, nodes6->value+i, 38, torrent); break; case 'E': @@ -2148,8 +2173,8 @@ int refresh (struct dht * d, int fam) { node_free(old); continue; case questionable: - if (!(rand() % (QUESTIONABLE_AFTER/PERIODIC))) - ping_node(d, &(*n)->addr); // NOTE03 about not pinging questionable nodes: this ensures a constant regeneration of the routing table. this is just an idea, if the client frequently gets in a situation without any nodes in the routing table, remove the comment before ping_node call. + // if (!(rand() % ())) // I disabled it again because it was too spammy + // ping_node(d, &(*n)->addr); // NOTE03 about not pinging questionable nodes: this ensures a constant regeneration of the routing table. this is just an idea, if the client frequently gets in a situation without any nodes in the routing table, remove the comment before ping_node call. break; // update on why I uncommented: to mitigate sybil attack, it's baje important to prefer old nodes case good: nrgood++; @@ -2159,7 +2184,8 @@ int refresh (struct dht * d, int fam) { } b = b->next; } - if (buckets > 32) { // sybil attack - node is broken - clear whole routing table, keeping one bucket + if (buckets > 64) { // sybil attack - node is broken - clear whole routing table, keeping one bucket + dht_print(d->log, d); L(disagreement, d, "@@@@@@ SYBIL ATTACK - CLEARING ROUTING TABLE @@@@@@"); int keep_first = rand() % 2; // should we even keep one bucket? the sybil node has a 1/2 if (keep_first) { // chance of having stared in the bucket farthest away, so it's stored there ... @@ -2215,7 +2241,6 @@ int refresh (struct dht * d, int fam) { void periodic (struct dht * d) { d->periods++; - L(debug, d, "called"); int dns = 0; if (!refresh(d, AF_INET)) dns++; @@ -2277,6 +2302,8 @@ void periodic (struct dht * d) { ; struct torrent * t = d->torrents; while (t) { + if (t->ttl && seconds() > t->ttl) + t->type = 0; if (t->type & (peers | announce)) { /* struct node * n = t->nodes; @@ -2388,7 +2415,7 @@ void periodic (struct dht * d) { struct peer * p = t->peers; int c = 0; while (p) { - if (!(p->flags & (badmeta | nometasupport | unreachable))) + if (!(p->flags & (badmeta | nometasupport | unreachable | protocolerror))) c++; p = p->next; } @@ -2397,7 +2424,7 @@ void periodic (struct dht * d) { int s = rand() % c; // OB1 untested p = t->peers; while (p) { - if (!(p->flags & (badmeta | nometasupport | unreachable)) && !s--) { + if (!(p->flags & (badmeta | nometasupport | unreachable | protocolerror)) && !s--) { t->dl = p; t->state = 0; t->socket = socket(AF_INET6, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, 0); @@ -2435,7 +2462,10 @@ void periodic (struct dht * d) { a: t = t->next; } - return; + L(debug, d, "txqp=%u rxrp=%u rxqp=%u txrp=%u", d->txqp, d->rxrp, d->rxqp, d->txrp); + if (d->txqp > 16384 || d->rxrp > 16384 || d->rxqp > 16384 || d->txrp > 16384) + raise(SIGINT); + d->txqp = d->txrp = d->rxqp = d->rxrp = 0; } /** @@ -2506,9 +2536,10 @@ void tcp_work (struct dht * d) { } if (!(t->state & ~(handshake_sent | incoming | outgoing))) { int ret = recv(t->socket, packet, 1+19+8+20*2, MSG_DONTWAIT); + L(expected, d, "handshake recv returned value %d, t->recvd == %d", ret, t->recvd); if (ret == 0) { L(disagreement, d, "received 0 bytes instead of handshake. EOF"); - t->dl->flags |= nometasupport; + t->dl->flags |= protocolerror; disconnect(t); goto c; } @@ -2522,7 +2553,7 @@ void tcp_work (struct dht * d) { } if (ret < 1+19+8+20*2) { // c'mon, this could've arrived in one packet HACK UGLY! L(disagreement, d, "expected handshake, received only %d bytes", ret); - t->dl->flags |= nometasupport; // cause it sent a nonsensical packet + t->dl->flags |= protocolerror; // cause it sent a nonsensical packet disconnect(t); goto c; } @@ -2554,31 +2585,44 @@ void tcp_work (struct dht * d) { disconnect(t); } goto c; + } else if (!ret){ + L(disagreement, d, "peer EOF"); + t->dl->flags |= protocolerror; + disconnect(t); + goto c; } else { - uint32_t l = ntohl(*((uint32_t *) t->packet)); - L(debug, d, "found length of a packet to be %u", l); d->tr += ret; t->recvd += ret; } + if (t->recvd == 4) { + uint32_t l = ntohl(*((uint32_t *) t->packet)); + L(debug, d, "found length of a packet to be %u", l); + } } if (t->recvd >= 4) { + char buf[41]; + buf[40] = '\0'; + bin2hex(buf, t->packet, MIN(20, t->recvd)); if (t->packet[0]) { - char buf[41]; - buf[40] = '\0'; - bin2hex(buf, t->packet, 20); - L(disagreement, d, "peer wants to send too big of a packet %s", buf); - t->dl->flags |= nometasupport; // too big pkt, sorry + L(disagreement, d, "peer wants to send too big of a packet %.*s", MIN(20, t->recvd)*2, buf); + t->dl->flags |= protocolerror; // too big pkt, sorry disconnect(t); goto c; } uint32_t l = ntohl(*((uint32_t *) t->packet)); - int ret = recv(t->socket, t->packet+t->recvd, MIN(l, 32727-t->recvd), MSG_DONTWAIT); + int ret = recv(t->socket, t->packet+t->recvd, MIN(l-t->recvd+4, 32727-t->recvd), MSG_DONTWAIT); + L(debug, d, "reading packet content: read %d bytes", ret); if (ret < 0) { if (errno != EAGAIN) { L(std_fail, d, "recv(TCP): %s (%d)", strerror(errno), errno); disconnect(t); } goto c; + } else if (!ret) { + L(disagreement, d, "peer EOF"); + t->dl->flags |= protocolerror; + disconnect(t); + goto c; } else { d->tr += ret; t->recvd += ret; @@ -2720,6 +2764,7 @@ void tcp_work (struct dht * d) { } free_bencoding(e); end_packet: + L(debug, d, "cleared packet recvd to 0"); t->recvd = 0; } /* @@ -31,19 +31,33 @@ void handler (int s) { break; } } +time_t last_added = 0; void found_torrent (struct dht * d __attribute__((unused)), const unsigned char * h, struct torrent * t) { char buf[128]; bin2hex(buf, h, 20); buf[40] = '\0'; - L(debug, d, "magnet:?xt=urn:btih:%s%s", buf, t ? " stored" : ""); + struct stat statbuf; + strcat(buf, ".torrent"); + if (!stat(buf, &statbuf)) { + L(expected, d, "%s already exists", buf); + return; + } + L(debug, d, "%s%s", buf, t ? " stored" : " new"); if (t) { - struct stat statbuf; - strcat(buf, ".torrent"); - if (!stat(buf, &statbuf)) { - L(expected, d, "%s already exists", buf); + if (!t->type) + t->ttl = seconds()+512; + t->type |= info | peers; + } else { + if (last_added + 10 > seconds()) { + L(debug, d, "not adding a torrent this fast"); return; - } else - t->type |= info | peers; + } + last_added = seconds(); + t = torrent_init(); + memcpy(t->hash, h, 20); + t->type |= info | peers; + t->ttl = seconds()+128; + add_torrent(d, t); } } int main (int argc, char ** argv) { @@ -114,6 +128,8 @@ int main (int argc, char ** argv) { dht->pollfds_size = &pollfds_size; dht->nfds = &nfds; dht->verbosity |= (getenv("TRAVNIK_INCOMING_DHT") ? incoming_dht : 0) | (getenv("TRAVNIK_OUTGOING_DHT") ? outgoing_dht : 0) | expected | debug; + dht->torrents_max = K; + dht->peers_per_torrent_max = K; struct torrent * torrent = torrent_init(); memcpy(torrent->hash, "\xdd\x82\x55\xec\xdc\x7c\xa5\x5f\xb0\xbb\xf8\x13\x23\xd8\x70\x62\xdb\x1f\x6d\x1c", 20); torrent->type = /* (useless, since we have no listening system yet) announce | */ peers | info; @@ -121,8 +137,22 @@ int main (int argc, char ** argv) { periodic(dht); // alarm(PERIODIC); w: - while (poll(pollfds, nfds, -1) != -1) // can't timeout + while (poll(pollfds, nfds, -1) != -1) { // can't timeout + if (sigusr1) { + sigusr1 = 0; + dht_print(stdout, dht); + goto w; + } + if (periodično) { + periodično = 0; + // alarm(PERIODIC); + periodic(dht); + goto w; + } + if (samomor) + goto s; work(dht); + } switch (errno) { case EINTR: if (sigusr1) { @@ -146,6 +176,7 @@ w: r = 115; goto r; } + s: config = persistent(dht); dht_free(dht); dht = NULL; |