X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=dht-bootstrap.c;h=9b6f714a7324df36078c6006464eea1fcc3bfb9c;hb=8343888afd4658e381d7c9f6323ce7690b65ee9d;hp=de5bb395c5416b1412712d76e3688f519a1b2092;hpb=5ce75cf1b18f93fc109bf860b7ad900f7a42542d;p=dht-bootstrap.git diff --git a/dht-bootstrap.c b/dht-bootstrap.c index de5bb39..9b6f714 100644 --- a/dht-bootstrap.c +++ b/dht-bootstrap.c @@ -20,62 +20,28 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ -#include +#include #include #include #include #include -#include +#include #include #include #include -#include -#include -#include #include #include -#define MAX(x, y) ((x) >= (y) ? (x) : (y)) +#include +#include +#include +#include +#include + +#undef MIN #define MIN(x, y) ((x) <= (y) ? (x) : (y)) -static int -send_ping(struct sockaddr *sa, int salen, const unsigned char *tid, int tid_len); -static int -send_pong(struct sockaddr *sa, int salen, const unsigned char *tid, int tid_len); -static int -send_find_node( - struct sockaddr *sa, - int salen, - const unsigned char *tid, - int tid_len, - const unsigned char *target, - int want); -static int -send_nodes( - struct sockaddr *sa, - int salen, - const unsigned char *tid, - int tid_len, - const unsigned char *nodes, - int nodes_len, - const unsigned char *nodes6, - int nodes6_len); -static int -send_random_nodes( - struct sockaddr *sa, - int salen, - const unsigned char *tid, - int tid_len, - const unsigned char *id, - int want); -static int -send_error( - struct sockaddr *sa, - int salen, - unsigned char *tid, - int tid_len, - int code, - const char *message); +#define MAX_PKT_SIZE 1536 #define ERROR 0 #define REPLY 1 @@ -87,34 +53,11 @@ send_error( #define WANT4 1 #define WANT6 2 -static int -parse_message( - const unsigned char *buf, - int buflen, - unsigned char *tid_return, - int *tid_len, - unsigned char *id_return, - unsigned char *info_hash_return, - unsigned char *target_return, - unsigned short *port_return, - unsigned char *token_return, - int *token_len, - unsigned char *nodes_return, - int *nodes_len, - unsigned char *nodes6_return, - int *nodes6_len, - unsigned char *values_return, - int *values_len, - unsigned char *values6_return, - int *values6_len, - int *want_return); - static const unsigned char zeroes[20] = {0}; static const unsigned char v4prefix[16] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0}; static unsigned char myid[20]; -static int have_v = 0; static unsigned char my_v[9]; static int dht_socket = -1; @@ -124,6 +67,7 @@ struct node { unsigned char id[160]; struct sockaddr_storage ss; socklen_t sslen; + char _pad[4]; }; #define CIRCULAR_LIST_SIZE 256 @@ -134,40 +78,309 @@ struct circular_list { struct node nodes[CIRCULAR_LIST_SIZE]; }; -struct circular_list v4_new, v6_new, v4_confirmed, v6_confirmed; +static struct circular_list v4_new, v6_new, v4_confirmed, v6_confirmed; #define MAX_TOKEN_BUCKET_TOKENS 40 static time_t token_bucket_time; static int token_bucket_tokens; -FILE *dht_debug = NULL; +static bool verbose = true; -#ifdef __GNUC__ -__attribute__((format(printf, 1, 2))) -#endif -static void -debugf(const char *format, ...) +struct Pkt { + unsigned char buf[MAX_PKT_SIZE]; + struct sockaddr_storage ss; + size_t len; + socklen_t salen; + char _pad[4]; +}; + +static struct Pkt pkt; +static int sockW = -1; + +// ------------------------ >8 ------------------------ + +static const char * +getAddr(const struct sockaddr *sa, const socklen_t saLen) { - va_list args; - va_start(args, format); - if (dht_debug) - vfprintf(dht_debug, format, args); - va_end(args); - fflush(dht_debug); + static char host[NI_MAXHOST]; + static char port[NI_MAXSERV]; + static char addr[64]; + int rc = getnameinfo( + sa, + saLen, + host, + sizeof host, + port, + sizeof port, + NI_NUMERICHOST | NI_NUMERICSERV); + if (rc != 0) { + fprintf(stderr, "getnameinfo: %s\n", gai_strerror(rc)); + return NULL; + } + snprintf(addr, sizeof addr, "[%s]:%s", host, port); + return addr; } static int -is_martian(struct sockaddr *sa) +parse_message( + const unsigned char *buf, + const size_t buflen, + unsigned char *tid_return, + size_t *tid_len, + unsigned char *id_return, + unsigned char *info_hash_return, + unsigned char *target_return, + unsigned short *port_return, + unsigned char *token_return, + size_t *token_len, + unsigned char *nodes_return, + size_t *nodes_len, + unsigned char *nodes6_return, + size_t *nodes6_len, + unsigned char *values_return, + size_t *values_len, + unsigned char *values6_return, + size_t *values6_len, + int *want_return, + const struct sockaddr *sa, + const socklen_t saLen) { - switch (sa->sa_family) { + /* This code will happily crash if the buffer is not NUL-terminated. */ + if (buf[buflen] != '\0') { + if (verbose) + printf("%s : parse_message with unterminated buffer\n", getAddr(sa, saLen)); + return -1; + } + +#define CHECK(ptr, len) \ + if (((const unsigned char *)ptr) + (len) > (buf) + (buflen)) \ + goto overflow; + + unsigned char *p; + unsigned long l = 0; + char *q; + if (tid_return) { + p = memmem(buf, buflen, "1:t", 3); + if (p) { + l = strtoul((const char *)p + 3, &q, 10); + if (q && *q == ':' && l > 0 && l < *tid_len) { + CHECK(q + 1, l); + memcpy(tid_return, q + 1, l); + *tid_len = l; + } else + *tid_len = 0; + } + } + if (id_return) { + p = memmem(buf, buflen, "2:id20:", 7); + if (p) { + CHECK(p + 7, 20); + memcpy(id_return, p + 7, 20); + } else { + memset(id_return, 0, 20); + } + } + if (info_hash_return) { + p = memmem(buf, buflen, "9:info_hash20:", 14); + if (p) { + CHECK(p + 14, 20); + memcpy(info_hash_return, p + 14, 20); + } else { + memset(info_hash_return, 0, 20); + } + } + if (port_return) { + p = memmem(buf, buflen, "porti", 5); + if (p) { + l = strtoul((const char *)p + 5, &q, 10); + if (q && *q == 'e' && l > 0 && l < 0x10000) + *port_return = (unsigned short)l; + else + *port_return = 0; + } else + *port_return = 0; + } + if (target_return) { + p = memmem(buf, buflen, "6:target20:", 11); + if (p) { + CHECK(p + 11, 20); + memcpy(target_return, p + 11, 20); + } else { + memset(target_return, 0, 20); + } + } + if (token_return) { + p = memmem(buf, buflen, "5:token", 7); + if (p) { + l = strtoul((const char *)p + 7, &q, 10); + if (q && *q == ':' && l > 0 && l < *token_len) { + CHECK(q + 1, l); + memcpy(token_return, q + 1, l); + *token_len = l; + } else + *token_len = 0; + } else + *token_len = 0; + } + + if (nodes_len) { + p = memmem(buf, buflen, "5:nodes", 7); + if (p) { + l = strtoul((const char *)p + 7, &q, 10); + if (q && *q == ':' && l > 0 && l < *nodes_len) { + CHECK(q + 1, l); + memcpy(nodes_return, q + 1, l); + *nodes_len = l; + } else + *nodes_len = 0; + } else + *nodes_len = 0; + } + + if (nodes6_len) { + p = memmem(buf, buflen, "6:nodes6", 8); + if (p) { + l = strtoul((const char *)p + 8, &q, 10); + if (q && *q == ':' && l > 0 && l < *nodes6_len) { + CHECK(q + 1, l); + memcpy(nodes6_return, q + 1, l); + *nodes6_len = l; + } else + *nodes6_len = 0; + } else + *nodes6_len = 0; + } + + if (values_len || values6_len) { + p = memmem(buf, buflen, "6:valuesl", 9); + if (p) { + size_t i = p - buf + 9; + unsigned long j = 0, j6 = 0; + for (;;) { + l = strtoul((const char *)buf + i, &q, 10); + if (q && *q == ':' && l > 0) { + CHECK(q + 1, l); + if (l == 6) { + if (j + l > *values_len) + continue; + i = q + 1 + l - (const char *)buf; + memcpy((char *)values_return + j, q + 1, l); + j += l; + } else if (l == 18) { + if (j6 + l > *values6_len) + continue; + i = q + 1 + l - (const char *)buf; + memcpy((char *)values6_return + j6, q + 1, l); + j6 += l; + } else { + if (verbose) + printf( + "%s : received weird value: %d bytes\n", + getAddr(sa, saLen), + (int)l); + i = q + 1 + l - (const char *)buf; + } + } else { + break; + } + } + if (i >= buflen || buf[i] != 'e') + if (verbose) + printf("%s : unexpected end for values\n", getAddr(sa, saLen)); + if (values_len) + *values_len = j; + if (values6_len) + *values6_len = j6; + } else { + *values_len = 0; + *values6_len = 0; + } + } + + if (want_return) { + p = memmem(buf, buflen, "4:wantl", 7); + if (p) { + size_t i = p - buf + 7; + *want_return = 0; + while (buf[i] > '0' && buf[i] <= '9' && buf[i + 1] == ':' && + i + 2 + buf[i] - '0' < buflen) { + CHECK(buf + i + 2, buf[i] - '0'); + if (buf[i] == '2' && memcmp(buf + i + 2, "n4", 2) == 0) + *want_return |= WANT4; + else if (buf[i] == '2' && memcmp(buf + i + 2, "n6", 2) == 0) + *want_return |= WANT6; + else if (verbose) + printf( + "%s : unexpected want flag: %c\n", getAddr(sa, saLen), buf[i]); + i += 2 + buf[i] - '0'; + } + if (i >= buflen || buf[i] != 'e') + if (verbose) + printf("%s : unexpected end for want\n", getAddr(sa, saLen)); + } else { + *want_return = -1; + } + } + +#undef CHECK + + if (memmem(buf, buflen, "1:y1:r", 6)) + return REPLY; + if (memmem(buf, buflen, "1:y1:e", 6)) + return ERROR; + if (!memmem(buf, buflen, "1:y1:q", 6)) + return -1; + if (memmem(buf, buflen, "1:q4:ping", 9)) + return PING; + if (memmem(buf, buflen, "1:q9:find_node", 14)) + return FIND_NODE; + if (memmem(buf, buflen, "1:q9:get_peers", 14)) + return GET_PEERS; + if (memmem(buf, buflen, "1:q13:announce_peer", 19)) + return ANNOUNCE_PEER; + return -1; + +overflow: + if (verbose) + printf(": truncated message\n"); + return -1; +} + +#undef CHECK +#undef INC +#undef COPY +#undef ADD_V + +/* We could use a proper bencoding printer and parser, but the format of + DHT messages is fairly stylised, so this seemed simpler. */ + +#define CHECK(offset, delta, size) \ + if (delta < 0 || offset + delta > size) \ + goto fail + +#define INC(offset, delta, size) \ + CHECK(offset, delta, size); \ + offset += delta; + +#define COPY(buf, offset, src, delta, size) \ + CHECK(offset, delta, size); \ + memcpy(buf + offset, src, delta); \ + offset += delta; + +#define ADD_V(buf, offset, size) COPY(buf, offset, my_v, (sizeof my_v), size) + +static bool +is_martian(const struct sockaddr_storage *ss) +{ + switch (((const struct sockaddr *)ss)->sa_family) { case AF_INET: { - struct sockaddr_in *sin = (struct sockaddr_in *)sa; + const struct sockaddr_in *sin = (const struct sockaddr_in *)ss; const unsigned char *address = (const unsigned char *)&sin->sin_addr; return sin->sin_port == 0 || (address[0] == 0) || (address[0] == 127) || ((address[0] & 0xE0) == 0xE0); } case AF_INET6: { - struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa; + const struct sockaddr_in6 *sin6 = (const struct sockaddr_in6 *)ss; const unsigned char *address = (const unsigned char *)&sin6->sin6_addr; return sin6->sin6_port == 0 || (address[0] == 0xFF) || (address[0] == 0xFE && (address[1] & 0xC0) == 0x80) || @@ -175,10 +388,8 @@ is_martian(struct sockaddr *sa) (address[15] == 0 || address[15] == 1)) || (memcmp(address, v4prefix, 12) == 0); } - - default: - return 0; } + return false; } /* Forget about the ``XOR-metric''. An id is just a path from the @@ -196,7 +407,7 @@ id_cmp(const unsigned char *restrict id1, const unsigned char *restrict id2) host order. */ static void -make_tid(unsigned char *tid_return, const char *prefix, unsigned short seqno) +make_tid(unsigned char *tid_return, const char *prefix, const unsigned short seqno) { tid_return[0] = prefix[0] & 0xFF; tid_return[1] = prefix[1] & 0xFF; @@ -229,7 +440,7 @@ list_elements(struct circular_list *list) return circular(list->head, list->tail); } -static int +static bool list_empty(struct circular_list *list) { return list_elements(list) == 0; @@ -260,11 +471,10 @@ list_random( struct sockaddr_storage *ss, socklen_t *sslen) { - int n; if (list->head == list->tail) return 0; - n = random() % (list->tail - list->head); + int n = random() % (list->tail - list->head); n = (list->head + n) % CIRCULAR_LIST_SIZE; if (id) @@ -277,12 +487,14 @@ list_random( /* We just learnt about a node, not necessarily a new one. Confirm is 1 if the node sent a message, 2 if it sent us a reply. */ -static int -new_node(unsigned char *id, struct sockaddr *sa, socklen_t salen, int confirm) +static bool +new_node( + const unsigned char *id, + const struct sockaddr *sa, + const socklen_t salen, + const int confirm) { struct circular_list *list; - int i; - if (sa->sa_family == AF_INET) list = confirm >= 2 ? &v4_confirmed : &v4_new; else if (sa->sa_family == AF_INET6) @@ -295,12 +507,12 @@ new_node(unsigned char *id, struct sockaddr *sa, socklen_t salen, int confirm) include such a node if we have plenty of space. */ if (confirm == 1 && list_free(list) < 32) - return 0; + return false; - for (i = list->head; i != list->tail; i = (i + 1) % CIRCULAR_LIST_SIZE) { + for (int i = list->head; i != list->tail; i = (i + 1) % CIRCULAR_LIST_SIZE) { struct node *n = &list->nodes[i]; if (n->sslen == salen && memcmp(&n->ss, sa, salen) == 0) - return 0; + return false; } memcpy(&list->nodes[list->tail].id, id, 160); @@ -309,59 +521,186 @@ new_node(unsigned char *id, struct sockaddr *sa, socklen_t salen, int confirm) list->tail = (list->tail + 1) % CIRCULAR_LIST_SIZE; if (list->head == list->tail) list->head = (list->head + 1) % CIRCULAR_LIST_SIZE; + if (verbose) + printf("%s : new node\n", getAddr(sa, salen)); - return 1; + return true; } -static int +static bool token_bucket(void) { time_t now = time(NULL); if (token_bucket_tokens == 0) { token_bucket_tokens = - MIN(MAX_TOKEN_BUCKET_TOKENS, 4 * (now - token_bucket_time)); + MIN(MAX_TOKEN_BUCKET_TOKENS, 4 * (int)(now - token_bucket_time)); token_bucket_time = now; } - if (token_bucket_tokens == 0) - return 0; - + return false; token_bucket_tokens--; - return 1; + return true; } -static int -send_request(struct circular_list *list, int dopop, int doping, int want) +static ssize_t +pktSend(const struct Pkt *p) { - unsigned char ttid[4]; - struct sockaddr_storage ss; - socklen_t sslen; - int rc; + int s = -1; + const struct sockaddr *sa = (const struct sockaddr *)&(p->ss); + switch (sa->sa_family) { + case AF_INET: + s = dht_socket; + break; + case AF_INET6: + s = dht_socket6; + break; + default: + abort(); + } + return sendto(s, p->buf, p->len, 0, sa, p->salen); +} + +static ssize_t +dht_send( + const void *buf, + const size_t len, + const struct sockaddr *sa, + const socklen_t salen) +{ + if (salen == 0) + abort(); + memcpy(&(pkt.ss), sa, sizeof(struct sockaddr_storage)); + memcpy(pkt.buf, buf, len); + pkt.len = len; + pkt.salen = salen; + if (sockW == -1) + return pktSend(&pkt); + return write(sockW, &pkt, sizeof(struct Pkt)); +} + +static ssize_t +send_ping( + const struct sockaddr *sa, + const socklen_t salen, + const unsigned char *tid, + const size_t tid_len) +{ + char buf[512]; + int i = 0; + int rc = snprintf(buf + i, 512 - i, "d1:ad2:id20:"); + INC(i, rc, 512); + COPY(buf, i, myid, 20, 512); + rc = snprintf(buf + i, 512 - i, "e1:q4:ping1:t%zu:", tid_len); + INC(i, rc, 512); + COPY(buf, i, tid, tid_len, 512); + ADD_V(buf, i, 512); + rc = snprintf(buf + i, 512 - i, "1:y1:qe"); + INC(i, rc, 512); + if (verbose) + printf("%s <- PING\n", getAddr(sa, salen)); + return dht_send(buf, (size_t)i, sa, salen); + +fail: + errno = ENOSPC; + return -1; +} + +static ssize_t +send_pong( + const struct sockaddr *sa, + const socklen_t salen, + const unsigned char *tid, + const size_t tid_len) +{ + char buf[512]; + int i = 0; + int rc = snprintf(buf + i, 512 - i, "d1:rd2:id20:"); + INC(i, rc, 512); + COPY(buf, i, myid, 20, 512); + rc = snprintf(buf + i, 512 - i, "e1:t%zu:", tid_len); + INC(i, rc, 512); + COPY(buf, i, tid, tid_len, 512); + ADD_V(buf, i, 512); + rc = snprintf(buf + i, 512 - i, "1:y1:re"); + INC(i, rc, 512); + if (verbose) + printf("%s <- PONG\n", getAddr(sa, salen)); + return dht_send(buf, (size_t)i, sa, salen); + +fail: + errno = ENOSPC; + return -1; +} + +static ssize_t +send_find_node( + const struct sockaddr *sa, + const socklen_t salen, + const unsigned char *tid, + const size_t tid_len, + const unsigned char *target, + const int want) +{ + char buf[512]; + int i = 0; + int rc = snprintf(buf + i, 512 - i, "d1:ad2:id20:"); + INC(i, rc, 512); + COPY(buf, i, myid, 20, 512); + rc = snprintf(buf + i, 512 - i, "6:target20:"); + INC(i, rc, 512); + COPY(buf, i, target, 20, 512); + if (want > 0) { + rc = snprintf( + buf + i, + 512 - i, + "4:wantl%s%se", + (want & WANT4) ? "2:n4" : "", + (want & WANT6) ? "2:n6" : ""); + INC(i, rc, 512); + } + rc = snprintf(buf + i, 512 - i, "e1:q9:find_node1:t%zu:", tid_len); + INC(i, rc, 512); + COPY(buf, i, tid, tid_len, 512); + ADD_V(buf, i, 512); + rc = snprintf(buf + i, 512 - i, "1:y1:qe"); + INC(i, rc, 512); + if (verbose) + printf("%s <- FIND_NODE\n", getAddr(sa, salen)); + return dht_send(buf, (size_t)i, sa, salen); +fail: + errno = ENOSPC; + return -1; +} + +static ssize_t +send_request( + struct circular_list *list, + const bool dopop, + const bool doping, + const int want) +{ if (list_empty(list)) return 0; + struct sockaddr_storage ss; + socklen_t sslen; if (dopop) { - rc = list_pop(list, &ss, &sslen); - if (rc == 0) + if (list_pop(list, &ss, &sslen) == 0) return 0; } else { - rc = list_random(list, NULL, &ss, &sslen); - if (rc == 0) + if (list_random(list, NULL, &ss, &sslen) == 0) return 0; } + unsigned char ttid[4]; if (doping) { make_tid(ttid, "pn", 0); - debugf("Sending ping.\n"); return send_ping((struct sockaddr *)&ss, sslen, ttid, 4); } else { unsigned char id[20]; - int i; - for (i = 0; i < 20; i++) - id[i] = random() & 0xFF; + arc4random_buf(id, sizeof id); make_tid(ttid, "fn", 0); - debugf("Sending find_node.\n"); return send_find_node((struct sockaddr *)&ss, sslen, ttid, 4, id, want); } } @@ -374,51 +713,187 @@ newSock(const char *host, const char *port) hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_DGRAM; struct addrinfo *res = NULL; - int err = getaddrinfo(host, port, &hints, &res); - if (err != 0) { - fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(err)); - exit(1); - } + int rc = getaddrinfo(host, port, &hints, &res); + if (rc != 0) + err(EXIT_FAILURE, "getaddrinfo: %s\n", gai_strerror(rc)); int sock = socket(res->ai_family, res->ai_socktype, res->ai_protocol); - if (sock == -1) { - perror("socket"); - exit(1); + if (sock == -1) + err(EXIT_FAILURE, "socket()"); + if (bind(sock, res->ai_addr, res->ai_addrlen) != 0) + err(EXIT_FAILURE, "bind()"); + rc = fcntl(sock, F_GETFL, 0); + if (rc < 0) + err(EXIT_FAILURE, "F_GETFL"); + rc = fcntl(sock, F_SETFL, (rc | O_NONBLOCK)); + if (rc < 0) + err(EXIT_FAILURE, "F_SETFL"); + freeaddrinfo(res); + return sock; +} + +static void +rlimited(int res) +{ + struct rlimit r; + r.rlim_cur = 0; + r.rlim_max = 0; + if (setrlimit(res, &r) == -1) { + err(EXIT_FAILURE, "setrlimit()"); } - if (bind(sock, res->ai_addr, res->ai_addrlen) != 0) { - perror("bind"); - exit(1); +} + +static ssize_t +send_nodes( + const struct sockaddr *sa, + const socklen_t salen, + const unsigned char *tid, + const size_t tid_len, + const unsigned char *nodes, + const size_t nodes_len, + const unsigned char *nodes6, + const size_t nodes6_len) +{ + char buf[2048]; + int i = 0; + int rc = snprintf(buf + i, 2048 - i, "d1:rd2:id20:"); + INC(i, rc, 2048); + COPY(buf, i, myid, 20, 2048); + if (nodes_len > 0) { + rc = snprintf(buf + i, 2048 - i, "5:nodes%zu:", nodes_len); + INC(i, rc, 2048); + COPY(buf, i, nodes, nodes_len, 2048); } - int rc = fcntl(sock, F_GETFL, 0); - if (rc < 0) { - perror("F_GETFL"); - exit(1); + if (nodes6_len > 0) { + rc = snprintf(buf + i, 2048 - i, "6:nodes6%zu:", nodes6_len); + INC(i, rc, 2048); + COPY(buf, i, nodes6, nodes6_len, 2048); } - rc = fcntl(sock, F_SETFL, (rc | O_NONBLOCK)); - if (rc < 0) { - perror("F_SETFL"); - exit(1); + rc = snprintf(buf + i, 2048 - i, "e1:t%zu:", tid_len); + INC(i, rc, 2048); + COPY(buf, i, tid, tid_len, 2048); + ADD_V(buf, i, 2048); + rc = snprintf(buf + i, 2048 - i, "1:y1:re"); + INC(i, rc, 2048); + return dht_send(buf, (size_t)i, sa, salen); + +fail: + errno = ENOSPC; + return -1; +} + +static int +buffer_random_nodes(int af, unsigned char *nodes) +{ + struct circular_list *list; + switch (af) { + case AF_INET: + list = &v4_confirmed; + break; + case AF_INET6: + list = &v6_confirmed; + break; + default: + abort(); } - freeaddrinfo(res); - return sock; + + struct sockaddr_storage ss; + socklen_t sslen; + unsigned char id[20]; + int n = 0; + while (n < 8) { + if (list_random(list, id, &ss, &sslen) < 1) + break; + switch (af) { + case AF_INET: { + struct sockaddr_in *sin = (struct sockaddr_in *)&ss; + memcpy(nodes + n * 26, id, 20); + memcpy(nodes + n * 26 + 20, &sin->sin_addr, 4); + memcpy(nodes + n * 26 + 24, &sin->sin_port, 2); + n++; + break; + } + case AF_INET6: { + struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&ss; + memcpy(nodes + n * 38, id, 20); + memcpy(nodes + n * 38 + 20, &sin6->sin6_addr, 16); + memcpy(nodes + n * 38 + 36, &sin6->sin6_port, 2); + n++; + break; + } + default: + abort(); + } + } + return n; +} + +static ssize_t +send_random_nodes( + const struct sockaddr *sa, + const socklen_t salen, + const unsigned char *tid, + const size_t tid_len, + int want) +{ + unsigned char nodes[8 * 26]; + unsigned char nodes6[8 * 38]; + int numnodes = 0; + int numnodes6 = 0; + if (want < 0) + want = sa->sa_family == AF_INET ? WANT4 : WANT6; + if ((want & WANT4)) + numnodes = buffer_random_nodes(AF_INET, nodes); + if ((want & WANT6)) + numnodes6 = buffer_random_nodes(AF_INET6, nodes6); + if (verbose) + printf("%s <- NODES (%d+%d)\n", getAddr(sa, salen), numnodes, numnodes6); + return send_nodes( + sa, salen, tid, tid_len, nodes, numnodes * 26, nodes6, numnodes6 * 38); +} + +static ssize_t +send_error( + const struct sockaddr *sa, + const socklen_t salen, + const unsigned char *tid, + const size_t tid_len, + const int code, + const char *message) +{ + char buf[512]; + int i = 0; + int rc = snprintf(buf + i, 512 - i, "d1:eli%de%d:", code, (int)strlen(message)); + INC(i, rc, 512); + COPY(buf, i, message, (int)strlen(message), 512); + rc = snprintf(buf + i, 512 - i, "e1:t%zu:", tid_len); + INC(i, rc, 512); + COPY(buf, i, tid, tid_len, 512); + ADD_V(buf, i, 512); + rc = snprintf(buf + i, 512 - i, "1:y1:ee"); + INC(i, rc, 512); + return dht_send(buf, (size_t)i, sa, salen); + +fail: + errno = ENOSPC; + return -1; } int main(int argc, char **argv) { errno = 0; - int quiet = 0; char *ipv4addr = NULL; char *ipv6addr = NULL; int opt = 0; - while (1) { + for (;;) { opt = getopt(argc, argv, "q4:6:"); if (opt < 0) break; switch (opt) { case 'q': - quiet = 1; + verbose = 0; break; case '4': ipv4addr = strdup(optarg); @@ -436,42 +911,19 @@ main(int argc, char **argv) if (argc < i + 1) goto usage; - const char *port = strdup(argv[i++]); - + const char *ourPort = strdup(argv[i++]); if (ipv4addr != NULL) { - dht_socket = newSock(ipv4addr, port); + dht_socket = newSock(ipv4addr, ourPort); } if (ipv6addr != NULL) { - dht_socket6 = newSock(ipv6addr, port); - } - - int rc = 0; - { - int fd = open("/dev/urandom", O_RDONLY); - if (fd < 0) { - perror("open(random)"); - exit(1); - } - - rc = read(fd, myid, 20); - if (rc < 20) { - perror("open(random)"); - exit(1); - } - - unsigned int seed; - rc = read(fd, &seed, sizeof(seed)); - srandom(seed); - - close(fd); + dht_socket6 = newSock(ipv6addr, ourPort); } + arc4random_buf(myid, sizeof myid); memcpy(my_v, "1:v4:JB\0\0", 9); - have_v = 1; - - if (!quiet) - dht_debug = stdout; + memset(&(pkt.ss), 0, sizeof(struct sockaddr_storage)); + int rc = 0; unsigned char ttid[4]; while (i < argc) { @@ -484,10 +936,8 @@ main(int argc, char **argv) else if (dht_socket6 < 0) hints.ai_family |= AF_INET; rc = getaddrinfo(argv[i], argv[i + 1], &hints, &info); - if (rc != 0) { - fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rc)); - exit(1); - } + if (rc != 0) + err(EXIT_FAILURE, "getaddrinfo: %s\n", gai_strerror(rc)); i++; if (i >= argc) @@ -496,93 +946,145 @@ main(int argc, char **argv) infop = info; while (infop) { make_tid(ttid, "pn", 0); - debugf("Sending ping.\n"); - send_ping(infop->ai_addr, infop->ai_addrlen, ttid, 4); + if (send_ping(infop->ai_addr, infop->ai_addrlen, ttid, 4) == -1) + err(EXIT_FAILURE, "sendto()"); infop = infop->ai_next; } freeaddrinfo(info); - i++; } + close(STDIN_FILENO); + if (!verbose) + close(STDOUT_FILENO); + + int sockets[2]; + if (socketpair(PF_LOCAL, SOCK_DGRAM, 0, sockets) != 0) + err(EXIT_FAILURE, "socketpair()"); + int sockR = sockets[0]; + sockW = sockets[1]; + pid_t pid = fork(); + if (pid == -1) + err(EXIT_FAILURE, "fork()"); + if (pid == 0) { + close(sockW); + + rlimited(RLIMIT_NPROC); + rlimited(RLIMIT_FSIZE); + rlimited(RLIMIT_NOFILE); + ssize_t n = 0; + unsigned char buf[sizeof(struct Pkt)]; + for (;;) { + n = read(sockR, buf, sizeof buf); + if (n == -1) { + perror("read()"); + continue; + } + if (pktSend((struct Pkt *)buf) == -1) + perror("sendto()"); + } + } + close(sockR); + + cap_rights_t caprights; + cap_rights_init(&caprights, CAP_WRITE); + if (cap_rights_limit(STDERR_FILENO, &caprights) != 0) + err(EXIT_FAILURE, "cap_rights_limit(stderr)"); + if (!verbose) + if (cap_rights_limit(STDOUT_FILENO, &caprights) != 0) + err(EXIT_FAILURE, "cap_rights_limit(stdout)"); + if (cap_rights_limit(sockW, &caprights) != 0) + err(EXIT_FAILURE, "cap_rights_limit(sockW)"); + if (cap_enter() != 0) + err(EXIT_FAILURE, "cap_enter()"); + token_bucket_time = time(NULL); token_bucket_tokens = MAX_TOKEN_BUCKET_TOKENS; - int send4 = 0; - while (1) { - struct timeval tv; - fd_set readfds; + int kq = kqueue(); + if (kq == -1) + err(EXIT_FAILURE, "kqueue()"); + struct kevent chs[2]; + struct kevent ev; + int chsLen = 0; + if (dht_socket != -1) { + EV_SET(&(chs[chsLen]), dht_socket, EVFILT_READ, EV_ADD, 0, 0, NULL); + chsLen++; + } + if (dht_socket6 != -1) { + EV_SET(&(chs[chsLen]), dht_socket6, EVFILT_READ, EV_ADD, 0, 0, NULL); + chsLen++; + } + rlimited(RLIMIT_NPROC); + rlimited(RLIMIT_FSIZE); + rlimited(RLIMIT_NOFILE); + + struct timespec tm; + bool send4; + for (;;) { if ((dht_socket >= 0 && list_elements(&v4_confirmed) <= 16) || (dht_socket6 >= 0 && list_elements(&v6_confirmed) <= 16)) - tv.tv_sec = 0; + tm.tv_sec = 0; else - tv.tv_sec = random() % 30; - tv.tv_usec = random() % 1000000; - - FD_ZERO(&readfds); - if (dht_socket >= 0) - FD_SET(dht_socket, &readfds); - if (dht_socket6 >= 0) - FD_SET(dht_socket6, &readfds); - - if (dht_debug) - debugf( - "%d+%d %d+%d\n", - list_elements(&v4_confirmed), - list_elements(&v6_confirmed), - list_elements(&v4_new), - list_elements(&v6_new)); - - int rc = select(MAX(dht_socket, dht_socket6) + 1, &readfds, NULL, NULL, &tv); - - if (rc < 0) { - if (errno != EINTR) { - perror("select"); - sleep(1); - } - } + tm.tv_sec = random() % 30; + tm.tv_nsec = 1000000 * (random() % 1000); + + setproctitle_fast( + "%d+%d %d+%d", + list_elements(&v4_confirmed), + list_elements(&v6_confirmed), + list_elements(&v4_new), + list_elements(&v6_new)); + + rc = kevent(kq, chs, chsLen, &ev, 1, &tm); + if (rc < 0) + err(EXIT_FAILURE, "kevent()"); if (rc > 0) { - int rc = 0; - int message; - unsigned char tid[16], id[20], info_hash[20], target[20]; - unsigned char buf[1536], nodes[256], nodes6[1024], token[128]; - int tid_len = 16, token_len = 128; - int nodes_len = 256, nodes6_len = 1024; - unsigned short port; - unsigned char values[2048], values6[2048]; - int values_len = 2048, values6_len = 2048; - int want; + ssize_t got = -1; + unsigned char buf[MAX_PKT_SIZE]; struct sockaddr_storage source_storage; struct sockaddr *source = (struct sockaddr *)&source_storage; socklen_t sourcelen = sizeof(source_storage); - if (dht_socket >= 0 && FD_ISSET(dht_socket, &readfds)) { - rc = recvfrom(dht_socket, buf, 1536, 0, source, &sourcelen); - } else if (dht_socket6 >= 0 && FD_ISSET(dht_socket6, &readfds)) { - rc = recvfrom(dht_socket6, buf, 1536, 0, source, &sourcelen); + if (ev.flags & EV_ERROR) { + fprintf(stderr, "EV_ERROR: %s\n", strerror((int)(ev.data))); + } else { + got = recvfrom((int)ev.ident, buf, MAX_PKT_SIZE, 0, source, &sourcelen); } - - if (rc < 0 || sourcelen > sizeof(struct sockaddr_storage)) + if (got < 0 || sourcelen > sizeof(struct sockaddr_storage)) goto dontread; - - if (is_martian(source)) + if (is_martian(&source_storage)) goto dontread; - - /* There's a bug in parse_message -- it will happily overflow the - buffer if it's not NUL-terminated. For now, put a NUL at the - end of buffers. */ - - if (rc < 1536) { - buf[rc] = '\0'; + if (got < MAX_PKT_SIZE) { + buf[got] = '\0'; } else { - debugf("Overlong message.\n"); + if (verbose) + printf("%s : overlong message\n", getAddr(source, sourcelen)); goto dontread; } + int message; + unsigned char tid[16]; + unsigned char id[20]; + unsigned char info_hash[20]; + unsigned char target[20]; + unsigned char nodes[256]; + unsigned char nodes6[1024]; + unsigned char token[128]; + size_t tid_len = sizeof tid; + size_t token_len = sizeof token; + size_t nodes_len = sizeof nodes; + size_t nodes6_len = sizeof nodes6; + unsigned short port; + unsigned char values[2048]; + unsigned char values6[2048]; + size_t values_len = sizeof values; + size_t values6_len = sizeof values6; + int want; message = parse_message( buf, - rc, + (size_t)got, tid, &tid_len, id, @@ -599,17 +1101,25 @@ main(int argc, char **argv) &values_len, values6, &values6_len, - &want); + &want, + source, + sourcelen); if (id_cmp(id, myid) == 0) { - debugf("Received message from self.\n"); + if (verbose) + printf( + "%s : received message from self\n", + getAddr(source, sourcelen)); goto dontread; } if (message > REPLY) { /* Rate limit requests. */ if (!token_bucket()) { - debugf("Dropping request due to rate limiting.\n"); + if (verbose) + printf( + "%s : dropping request due to rate limiting\n", + getAddr(source, sourcelen)); goto dontread; } } @@ -617,20 +1127,33 @@ main(int argc, char **argv) switch (message) { case REPLY: if (tid_len != 4) { - debugf("Broken node truncates transaction ids.\n"); + if (verbose) + printf( + "%s : broken node truncates transaction ids\n", + getAddr(source, sourcelen)); goto dontread; } if (tid_match(tid, "pn", NULL)) { - debugf("Pong!\n"); + if (verbose) + printf("%s -> PONG\n", getAddr(source, sourcelen)); new_node(id, source, sourcelen, 2); } else if (tid_match(tid, "fn", NULL)) { - debugf("Nodes found!\n"); + if (verbose) + printf( + "%s -> NODES (%zu+%zu)\n", + getAddr(source, sourcelen), + nodes_len / 26, + nodes6_len / 38); if (nodes_len % 26 != 0 || nodes6_len % 38 != 0) { - debugf("Unexpected length for node info!\n"); + if (verbose) + printf( + "%s : unexpected length for node info\n", + getAddr(source, sourcelen)); } else { new_node(id, source, sourcelen, 2); - for (i = 0; i < nodes_len / 26; i++) { - unsigned char *ni = nodes + i * 26; + size_t n; + for (n = 0; n < nodes_len / 26; n++) { + unsigned char *ni = nodes + n * 26; struct sockaddr_in sin; if (id_cmp(ni, myid) == 0) continue; @@ -640,8 +1163,8 @@ main(int argc, char **argv) memcpy(&sin.sin_port, ni + 24, 2); new_node(ni, (struct sockaddr *)&sin, sizeof(sin), 0); } - for (i = 0; i < nodes6_len / 38; i++) { - unsigned char *ni = nodes6 + i * 38; + for (n = 0; n < nodes6_len / 38; n++) { + unsigned char *ni = nodes6 + n * 38; struct sockaddr_in6 sin6; if (id_cmp(ni, myid) == 0) continue; @@ -653,29 +1176,32 @@ main(int argc, char **argv) } } } else { - debugf("Unexpected reply!\n"); + if (verbose) + printf("%s : unexpected reply\n", getAddr(source, sourcelen)); goto dontread; } break; case PING: - debugf("Ping (%d)!\n", tid_len); + if (verbose) + printf("%s -> PING (%zu)\n", getAddr(source, sourcelen), tid_len); new_node(id, source, sourcelen, 1); - debugf("Sending pong.\n"); send_pong(source, sourcelen, tid, tid_len); break; case FIND_NODE: case GET_PEERS: - if (message == FIND_NODE) - debugf("Find node!\n"); - else - debugf("Get peers!\n"); + if (verbose) { + if (message == FIND_NODE) + printf("%s -> FIND_NODE\n", getAddr(source, sourcelen)); + else + printf("%s -> GET_PEERS\n", getAddr(source, sourcelen)); + } new_node(id, source, sourcelen, 1); - debugf("Sending nodes (%d).\n", want); - send_random_nodes(source, sourcelen, tid, tid_len, target, want); + send_random_nodes(source, sourcelen, tid, tid_len, want); break; case ANNOUNCE_PEER: - debugf("Announce peer!\n"); + if (verbose) + printf("%s -> ANNOUNCE_PEER\n", getAddr(source, sourcelen)); send_error( source, sourcelen, @@ -694,531 +1220,28 @@ main(int argc, char **argv) loop. */ if (dht_socket6 < 0) - send4 = 1; + send4 = true; else if (dht_socket < 0) - send4 = 0; + send4 = false; else - send4 = random() % 2; + send4 = (random() % 2) == 1; if (send4) { int want = dht_socket6 >= 0 && list_free(&v6_new) > 8 ? (WANT4 | WANT6) : 0; if (!list_empty(&v4_new)) - send_request(&v4_new, 1, list_free(&v4_new) < 8, want); + send_request(&v4_new, true, list_free(&v4_new) < 8, want); else if (!list_empty(&v4_confirmed)) - send_request(&v4_confirmed, 0, 0, want); + send_request(&v4_confirmed, false, false, want); } else { int want = dht_socket >= 0 && list_free(&v4_new) > 8 ? (WANT4 | WANT6) : 0; if (!list_empty(&v6_new)) - send_request(&v6_new, 1, list_free(&v6_new) < 8, want); + send_request(&v6_new, true, list_free(&v6_new) < 8, want); else if (!list_empty(&v6_confirmed)) - send_request(&v6_confirmed, 0, 0, want); + send_request(&v6_confirmed, false, false, want); } } - return 0; - usage: fprintf(stderr, "dht-bootstrap [-q] [-4 ADDR4] [-6 ADDR6] port [node port...]\n"); - exit(1); -} - -/* We could use a proper bencoding printer and parser, but the format of - DHT messages is fairly stylised, so this seemed simpler. */ - -#define CHECK(offset, delta, size) \ - if (delta < 0 || offset + delta > size) \ - goto fail - -#define INC(offset, delta, size) \ - CHECK(offset, delta, size); \ - offset += delta - -#define COPY(buf, offset, src, delta, size) \ - CHECK(offset, delta, size); \ - memcpy(buf + offset, src, delta); \ - offset += delta; - -#define ADD_V(buf, offset, size) \ - if (have_v) { \ - COPY(buf, offset, my_v, sizeof(my_v), size); \ - } - -static int -dht_send(const void *buf, size_t len, int flags, const struct sockaddr *sa, int salen) -{ - int s; - - if (salen == 0) - abort(); - - if (sa->sa_family == AF_INET) - s = dht_socket; - else if (sa->sa_family == AF_INET6) - s = dht_socket6; - else - s = -1; - - if (s < 0) { - errno = EAFNOSUPPORT; - return -1; - } - - return sendto(s, buf, len, flags, sa, salen); -} - -int -send_ping(struct sockaddr *sa, int salen, const unsigned char *tid, int tid_len) -{ - char buf[512]; - int i = 0, rc; - rc = snprintf(buf + i, 512 - i, "d1:ad2:id20:"); - INC(i, rc, 512); - COPY(buf, i, myid, 20, 512); - rc = snprintf(buf + i, 512 - i, "e1:q4:ping1:t%d:", tid_len); - INC(i, rc, 512); - COPY(buf, i, tid, tid_len, 512); - ADD_V(buf, i, 512); - rc = snprintf(buf + i, 512 - i, "1:y1:qe"); - INC(i, rc, 512); - return dht_send(buf, i, 0, sa, salen); - -fail: - errno = ENOSPC; - return -1; -} - -int -send_pong(struct sockaddr *sa, int salen, const unsigned char *tid, int tid_len) -{ - char buf[512]; - int i = 0, rc; - rc = snprintf(buf + i, 512 - i, "d1:rd2:id20:"); - INC(i, rc, 512); - COPY(buf, i, myid, 20, 512); - rc = snprintf(buf + i, 512 - i, "e1:t%d:", tid_len); - INC(i, rc, 512); - COPY(buf, i, tid, tid_len, 512); - ADD_V(buf, i, 512); - rc = snprintf(buf + i, 512 - i, "1:y1:re"); - INC(i, rc, 512); - return dht_send(buf, i, 0, sa, salen); - -fail: - errno = ENOSPC; - return -1; -} - -int -send_find_node( - struct sockaddr *sa, - int salen, - const unsigned char *tid, - int tid_len, - const unsigned char *target, - int want) -{ - char buf[512]; - int i = 0, rc; - rc = snprintf(buf + i, 512 - i, "d1:ad2:id20:"); - INC(i, rc, 512); - COPY(buf, i, myid, 20, 512); - rc = snprintf(buf + i, 512 - i, "6:target20:"); - INC(i, rc, 512); - COPY(buf, i, target, 20, 512); - if (want > 0) { - rc = snprintf( - buf + i, - 512 - i, - "4:wantl%s%se", - (want & WANT4) ? "2:n4" : "", - (want & WANT6) ? "2:n6" : ""); - INC(i, rc, 512); - } - rc = snprintf(buf + i, 512 - i, "e1:q9:find_node1:t%d:", tid_len); - INC(i, rc, 512); - COPY(buf, i, tid, tid_len, 512); - ADD_V(buf, i, 512); - rc = snprintf(buf + i, 512 - i, "1:y1:qe"); - INC(i, rc, 512); - return dht_send(buf, i, 0, sa, salen); - -fail: - errno = ENOSPC; - return -1; -} - -int -send_nodes( - struct sockaddr *sa, - int salen, - const unsigned char *tid, - int tid_len, - const unsigned char *nodes, - int nodes_len, - const unsigned char *nodes6, - int nodes6_len) -{ - char buf[2048]; - int i = 0, rc; - - rc = snprintf(buf + i, 2048 - i, "d1:rd2:id20:"); - INC(i, rc, 2048); - COPY(buf, i, myid, 20, 2048); - if (nodes_len > 0) { - rc = snprintf(buf + i, 2048 - i, "5:nodes%d:", nodes_len); - INC(i, rc, 2048); - COPY(buf, i, nodes, nodes_len, 2048); - } - if (nodes6_len > 0) { - rc = snprintf(buf + i, 2048 - i, "6:nodes6%d:", nodes6_len); - INC(i, rc, 2048); - COPY(buf, i, nodes6, nodes6_len, 2048); - } - - rc = snprintf(buf + i, 2048 - i, "e1:t%d:", tid_len); - INC(i, rc, 2048); - COPY(buf, i, tid, tid_len, 2048); - ADD_V(buf, i, 2048); - rc = snprintf(buf + i, 2048 - i, "1:y1:re"); - INC(i, rc, 2048); - - return dht_send(buf, i, 0, sa, salen); - -fail: - errno = ENOSPC; - return -1; -} - -static int -buffer_random_nodes(int af, unsigned char *nodes) -{ - struct circular_list *list; - struct sockaddr_storage ss; - socklen_t sslen; - unsigned char id[20]; - int n; - int rc; - - switch (af) { - case AF_INET: - list = &v4_confirmed; - break; - case AF_INET6: - list = &v6_confirmed; - break; - default: - abort(); - } - - n = 0; - while (n < 8) { - rc = list_random(list, id, &ss, &sslen); - if (rc < 1) - break; - switch (af) { - case AF_INET: { - struct sockaddr_in *sin = (struct sockaddr_in *)&ss; - memcpy(nodes + n * 26, id, 20); - memcpy(nodes + n * 26 + 20, &sin->sin_addr, 4); - memcpy(nodes + n * 26 + 24, &sin->sin_port, 2); - n++; - break; - } - case AF_INET6: { - struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&ss; - memcpy(nodes + n * 38, id, 20); - memcpy(nodes + n * 38 + 20, &sin6->sin6_addr, 16); - memcpy(nodes + n * 38 + 36, &sin6->sin6_port, 2); - n++; - break; - } - default: - abort(); - } - } - return n; -} - -int -send_random_nodes( - struct sockaddr *sa, - int salen, - const unsigned char *tid, - int tid_len, - const unsigned char *id, - int want) -{ - unsigned char nodes[8 * 26]; - unsigned char nodes6[8 * 38]; - int numnodes = 0, numnodes6 = 0; - - if (want < 0) - want = sa->sa_family == AF_INET ? WANT4 : WANT6; - - if ((want & WANT4)) - numnodes = buffer_random_nodes(AF_INET, nodes); - - if ((want & WANT6)) - numnodes6 = buffer_random_nodes(AF_INET6, nodes6); - - return send_nodes( - sa, salen, tid, tid_len, nodes, numnodes * 26, nodes6, numnodes6 * 38); -} - -static int -send_error( - struct sockaddr *sa, - int salen, - unsigned char *tid, - int tid_len, - int code, - const char *message) -{ - char buf[512]; - int i = 0, rc; - - rc = snprintf(buf + i, 512 - i, "d1:eli%de%d:", code, (int)strlen(message)); - INC(i, rc, 512); - COPY(buf, i, message, (int)strlen(message), 512); - rc = snprintf(buf + i, 512 - i, "e1:t%d:", tid_len); - INC(i, rc, 512); - COPY(buf, i, tid, tid_len, 512); - ADD_V(buf, i, 512); - rc = snprintf(buf + i, 512 - i, "1:y1:ee"); - INC(i, rc, 512); - return dht_send(buf, i, 0, sa, salen); - -fail: - errno = ENOSPC; - return -1; -} - -#undef CHECK -#undef INC -#undef COPY -#undef ADD_V - -static int -parse_message( - const unsigned char *buf, - int buflen, - unsigned char *tid_return, - int *tid_len, - unsigned char *id_return, - unsigned char *info_hash_return, - unsigned char *target_return, - unsigned short *port_return, - unsigned char *token_return, - int *token_len, - unsigned char *nodes_return, - int *nodes_len, - unsigned char *nodes6_return, - int *nodes6_len, - unsigned char *values_return, - int *values_len, - unsigned char *values6_return, - int *values6_len, - int *want_return) -{ - const unsigned char *p; - - /* This code will happily crash if the buffer is not NUL-terminated. */ - if (buf[buflen] != '\0') { - debugf("Eek! parse_message with unterminated buffer.\n"); - return -1; - } - -#define CHECK(ptr, len) \ - if (((unsigned char *)ptr) + (len) > (buf) + (buflen)) \ - goto overflow; - - if (tid_return) { - p = memmem(buf, buflen, "1:t", 3); - if (p) { - long l; - char *q; - l = strtol((char *)p + 3, &q, 10); - if (q && *q == ':' && l > 0 && l < *tid_len) { - CHECK(q + 1, l); - memcpy(tid_return, q + 1, l); - *tid_len = l; - } else - *tid_len = 0; - } - } - if (id_return) { - p = memmem(buf, buflen, "2:id20:", 7); - if (p) { - CHECK(p + 7, 20); - memcpy(id_return, p + 7, 20); - } else { - memset(id_return, 0, 20); - } - } - if (info_hash_return) { - p = memmem(buf, buflen, "9:info_hash20:", 14); - if (p) { - CHECK(p + 14, 20); - memcpy(info_hash_return, p + 14, 20); - } else { - memset(info_hash_return, 0, 20); - } - } - if (port_return) { - p = memmem(buf, buflen, "porti", 5); - if (p) { - long l; - char *q; - l = strtol((char *)p + 5, &q, 10); - if (q && *q == 'e' && l > 0 && l < 0x10000) - *port_return = l; - else - *port_return = 0; - } else - *port_return = 0; - } - if (target_return) { - p = memmem(buf, buflen, "6:target20:", 11); - if (p) { - CHECK(p + 11, 20); - memcpy(target_return, p + 11, 20); - } else { - memset(target_return, 0, 20); - } - } - if (token_return) { - p = memmem(buf, buflen, "5:token", 7); - if (p) { - long l; - char *q; - l = strtol((char *)p + 7, &q, 10); - if (q && *q == ':' && l > 0 && l < *token_len) { - CHECK(q + 1, l); - memcpy(token_return, q + 1, l); - *token_len = l; - } else - *token_len = 0; - } else - *token_len = 0; - } - - if (nodes_len) { - p = memmem(buf, buflen, "5:nodes", 7); - if (p) { - long l; - char *q; - l = strtol((char *)p + 7, &q, 10); - if (q && *q == ':' && l > 0 && l < *nodes_len) { - CHECK(q + 1, l); - memcpy(nodes_return, q + 1, l); - *nodes_len = l; - } else - *nodes_len = 0; - } else - *nodes_len = 0; - } - - if (nodes6_len) { - p = memmem(buf, buflen, "6:nodes6", 8); - if (p) { - long l; - char *q; - l = strtol((char *)p + 8, &q, 10); - if (q && *q == ':' && l > 0 && l < *nodes6_len) { - CHECK(q + 1, l); - memcpy(nodes6_return, q + 1, l); - *nodes6_len = l; - } else - *nodes6_len = 0; - } else - *nodes6_len = 0; - } - - if (values_len || values6_len) { - p = memmem(buf, buflen, "6:valuesl", 9); - if (p) { - int i = p - buf + 9; - int j = 0, j6 = 0; - while (1) { - long l; - char *q; - l = strtol((char *)buf + i, &q, 10); - if (q && *q == ':' && l > 0) { - CHECK(q + 1, l); - if (l == 6) { - if (j + l > *values_len) - continue; - i = q + 1 + l - (char *)buf; - memcpy((char *)values_return + j, q + 1, l); - j += l; - } else if (l == 18) { - if (j6 + l > *values6_len) - continue; - i = q + 1 + l - (char *)buf; - memcpy((char *)values6_return + j6, q + 1, l); - j6 += l; - } else { - debugf("Received weird value -- %d bytes.\n", (int)l); - i = q + 1 + l - (char *)buf; - } - } else { - break; - } - } - if (i >= buflen || buf[i] != 'e') - debugf("eek... unexpected end for values.\n"); - if (values_len) - *values_len = j; - if (values6_len) - *values6_len = j6; - } else { - *values_len = 0; - *values6_len = 0; - } - } - - if (want_return) { - p = memmem(buf, buflen, "4:wantl", 7); - if (p) { - int i = p - buf + 7; - *want_return = 0; - while (buf[i] > '0' && buf[i] <= '9' && buf[i + 1] == ':' && - i + 2 + buf[i] - '0' < buflen) { - CHECK(buf + i + 2, buf[i] - '0'); - if (buf[i] == '2' && memcmp(buf + i + 2, "n4", 2) == 0) - *want_return |= WANT4; - else if (buf[i] == '2' && memcmp(buf + i + 2, "n6", 2) == 0) - *want_return |= WANT6; - else - debugf("eek... unexpected want flag (%c)\n", buf[i]); - i += 2 + buf[i] - '0'; - } - if (i >= buflen || buf[i] != 'e') - debugf("eek... unexpected end for want.\n"); - } else { - *want_return = -1; - } - } - -#undef CHECK - - if (memmem(buf, buflen, "1:y1:r", 6)) - return REPLY; - if (memmem(buf, buflen, "1:y1:e", 6)) - return ERROR; - if (!memmem(buf, buflen, "1:y1:q", 6)) - return -1; - if (memmem(buf, buflen, "1:q4:ping", 9)) - return PING; - if (memmem(buf, buflen, "1:q9:find_node", 14)) - return FIND_NODE; - if (memmem(buf, buflen, "1:q9:get_peers", 14)) - return GET_PEERS; - if (memmem(buf, buflen, "1:q13:announce_peer", 19)) - return ANNOUNCE_PEER; - return -1; - -overflow: - debugf("Truncated message.\n"); - return -1; + exit(EXIT_FAILURE); }