X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=src%2Fdns%2Fgnunet-service-dns.c;h=6337538d10a9a8f83886772df29a606c38e7634c;hb=56389a7d277b05c9c2968b7ebd529a12f8be15eb;hp=63cee93bb0a166ad3dc943e790c48a1b1b296f0f;hpb=dd61bcd68f58de56d7e0d5e8773017af1cebd966;p=oweals%2Fgnunet.git diff --git a/src/dns/gnunet-service-dns.c b/src/dns/gnunet-service-dns.c index 63cee93bb..6337538d1 100644 --- a/src/dns/gnunet-service-dns.c +++ b/src/dns/gnunet-service-dns.c @@ -22,6 +22,19 @@ * @file dns/gnunet-service-dns.c * @brief service to intercept and modify DNS queries (and replies) of this system * @author Christian Grothoff + * + * For "secure" interaction with the legacy DNS system, we permit + * replies only to arrive within a 5s window (and they must match + * ports, IPs and request IDs). Furthermore, we let the OS pick a + * source port, opening up to 128 sockets per address family (IPv4 or + * IPv6). Those sockets are closed if they are not in use for 5s + * (which means they will be freshly randomized afterwards). For new + * requests, we pick a random slot in the array with 128 socket slots + * (and re-use an existing socket if the slot is still in use). Thus + * each request will be given one of 128 random source ports, and the + * 128 random source ports will also change "often" (less often if the + * system is very busy, each time if we are mostly idle). At the same + * time, the system will never use more than 256 UDP sockets. */ #include "platform.h" #include "gnunet_util_lib.h" @@ -31,11 +44,23 @@ #include "gnunet_signatures.h" #include "dns.h" #include "gnunet_dns_service.h" +#include "gnunet_dnsparser_lib.h" #include "gnunet_mesh_service.h" #include "gnunet_statistics_service.h" #include "gnunet_tun_lib.h" +/** + * Timeout for an external (Internet-DNS) DNS resolution + */ +#define REQUEST_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5) + +/** + * How many DNS sockets do we open at most at the same time? + * (technical socket maximum is this number x2 for IPv4+IPv6) + */ +#define DNS_SOCKET_MAX 128 + /** * Phases each request goes through. */ @@ -111,6 +136,34 @@ struct ClientRecord }; +/** + * UDP socket we are using for sending DNS requests to the Internet. + */ +struct RequestSocket +{ + + /** + * UDP socket we use for this request for IPv4 + */ + struct GNUNET_NETWORK_Handle *dnsout4; + + /** + * UDP socket we use for this request for IPv6 + */ + struct GNUNET_NETWORK_Handle *dnsout6; + + /** + * Task for reading from dnsout4 and dnsout6. + */ + GNUNET_SCHEDULER_TaskIdentifier read_task; + + /** + * When should this socket be closed? + */ + struct GNUNET_TIME_Absolute timeout; +}; + + /** * Entry we keep for each active request. */ @@ -129,6 +182,13 @@ struct RequestRecord */ char *payload; + /** + * Socket we are using to transmit this request (must match if we receive + * a response). Must NOT be freed as part of this request record (as it + * might be shared with other requests). + */ + struct GNUNET_NETWORK_Handle *dnsout; + /** * Source address of the original request (for sending response). */ @@ -139,6 +199,11 @@ struct RequestRecord */ struct sockaddr_storage dst_addr; + /** + * When should this request time out? + */ + struct GNUNET_TIME_Absolute timeout; + /** * ID of this request, also basis for hashing. Lowest 16 bit will * be our message ID when doing a global DNS request and our index @@ -164,7 +229,6 @@ struct RequestRecord }; - /** * State we keep for each DNS tunnel that terminates at this node. */ @@ -186,11 +250,23 @@ struct TunnelState */ char *reply; + /** + * Socket we are using to transmit this request (must match if we receive + * a response). Must NOT be freed as part of this request record (as it + * might be shared with other requests). + */ + struct GNUNET_NETWORK_Handle *dnsout; + /** * Address we sent the DNS request to. */ struct sockaddr_storage addr; + /** + * When should this request time out? + */ + struct GNUNET_TIME_Absolute timeout; + /** * Number of bytes in 'addr'. */ @@ -214,32 +290,9 @@ struct TunnelState /** - * The IPv4 UDP-Socket through which DNS-Resolves will be sent if they are not to be - * sent through gnunet. The port of this socket will not be hijacked. - */ -static struct GNUNET_NETWORK_Handle *dnsout4; - -/** - * The IPv6 UDP-Socket through which DNS-Resolves will be sent if they are not to be - * sent through gnunet. The port of this socket will not be hijacked. - */ -static struct GNUNET_NETWORK_Handle *dnsout6; - -/** - * Task for reading from dnsout4. - */ -static GNUNET_SCHEDULER_TaskIdentifier read4_task; - -/** - * Task for reading from dnsout6. - */ -static GNUNET_SCHEDULER_TaskIdentifier read6_task; - -/** - * The port bound to the socket dnsout (and/or dnsout6). We always (try) to bind - * both sockets to the same port. + * Global return value from 'main'. */ -static uint16_t dnsoutport; +static int global_ret; /** * The configuration to use @@ -259,7 +312,7 @@ static struct GNUNET_HELPER_Handle *hijacker; /** * Command-line arguments we are giving to the hijacker process. */ -static char *helper_argv[8]; +static char *helper_argv[7]; /** * Head of DLL of clients we consult. @@ -286,6 +339,11 @@ static struct RequestRecord requests[UINT16_MAX + 1]; */ static struct TunnelState *tunnels[UINT16_MAX + 1]; +/** + * Array of all open sockets for DNS requests. + */ +static struct RequestSocket sockets[DNS_SOCKET_MAX]; + /** * Generator for unique request IDs. */ @@ -304,6 +362,32 @@ static char *dns_exit; static struct GNUNET_MESH_Handle *mesh; +/** + * We're done with a RequestSocket, close it for now. + * + * @param rs request socket to clean up + */ +static void +cleanup_rs (struct RequestSocket *rs) +{ + if (NULL != rs->dnsout4) + { + GNUNET_NETWORK_socket_close (rs->dnsout4); + rs->dnsout4 = NULL; + } + if (NULL != rs->dnsout6) + { + GNUNET_NETWORK_socket_close (rs->dnsout6); + rs->dnsout6 = NULL; + } + if (GNUNET_SCHEDULER_NO_TASK != rs->read_task) + { + GNUNET_SCHEDULER_cancel (rs->read_task); + rs->read_task = GNUNET_SCHEDULER_NO_TASK; + } +} + + /** * We're done processing a DNS request, free associated memory. * @@ -335,29 +419,9 @@ cleanup_task (void *cls GNUNET_UNUSED, GNUNET_HELPER_stop (hijacker); hijacker = NULL; - for (i=0;i<8;i++) + for (i=0;i<7;i++) GNUNET_free_non_null (helper_argv[i]); - if (NULL != dnsout4) - { - GNUNET_NETWORK_socket_close (dnsout4); - dnsout4 = NULL; - } - if (GNUNET_SCHEDULER_NO_TASK != read4_task) - { - GNUNET_SCHEDULER_cancel (read4_task); - read4_task = GNUNET_SCHEDULER_NO_TASK; - } - if (NULL != dnsout6) - { - GNUNET_NETWORK_socket_close (dnsout6); - dnsout6 = NULL; - } - if (GNUNET_SCHEDULER_NO_TASK != read6_task) - { - GNUNET_SCHEDULER_cancel (read6_task); - read6_task = GNUNET_SCHEDULER_NO_TASK; - } - for (i=0;i<65536;i++) + for (i=0;i<=UINT16_MAX;i++) cleanup_rr (&requests[i]); GNUNET_SERVER_notification_context_destroy (nc); nc = NULL; @@ -371,6 +435,59 @@ cleanup_task (void *cls GNUNET_UNUSED, GNUNET_free (dns_exit); dns_exit = NULL; } + if (NULL != mesh) + { + GNUNET_MESH_disconnect(mesh); + mesh = NULL; + } +} + + +/** + * Open source port for sending DNS requests + * + * @param af AF_INET or AF_INET6 + * @return GNUNET_OK on success + */ +static struct GNUNET_NETWORK_Handle * +open_socket (int af) +{ + struct sockaddr_in a4; + struct sockaddr_in6 a6; + struct sockaddr *sa; + socklen_t alen; + struct GNUNET_NETWORK_Handle *ret; + + ret = GNUNET_NETWORK_socket_create (af, SOCK_DGRAM, 0); + if (NULL == ret) + return NULL; + switch (af) + { + case AF_INET: + memset (&a4, 0, alen = sizeof (struct sockaddr_in)); + sa = (struct sockaddr *) &a4; + break; + case AF_INET6: + memset (&a6, 0, alen = sizeof (struct sockaddr_in6)); + sa = (struct sockaddr *) &a6; + break; + default: + GNUNET_break (0); + GNUNET_NETWORK_socket_close (ret); + return NULL; + } + sa->sa_family = af; + if (GNUNET_OK != GNUNET_NETWORK_socket_bind (ret, + sa, + alen)) + { + GNUNET_log (GNUNET_ERROR_TYPE_ERROR, + _("Could not bind to any port: %s\n"), + STRERROR (errno)); + GNUNET_NETWORK_socket_close (ret); + return NULL; + } + return ret; } @@ -384,8 +501,8 @@ request_done (struct RequestRecord *rr) { struct GNUNET_MessageHeader *hdr; size_t reply_len; - uint16_t spt; - uint16_t dpt; + uint16_t source_port; + uint16_t destination_port; GNUNET_array_grow (rr->client_wait_list, rr->client_wait_list_length, @@ -423,7 +540,7 @@ request_done (struct RequestRecord *rr) return; } { - char buf[reply_len]; + char buf[reply_len] GNUNET_ALIGN; size_t off; struct GNUNET_TUN_IPv4Header ip4; struct GNUNET_TUN_IPv6Header ip6; @@ -455,8 +572,8 @@ request_done (struct RequestRecord *rr) struct sockaddr_in *src = (struct sockaddr_in *) &rr->src_addr; struct sockaddr_in *dst = (struct sockaddr_in *) &rr->dst_addr; - spt = dst->sin_port; - dpt = src->sin_port; + source_port = dst->sin_port; + destination_port = src->sin_port; GNUNET_TUN_initialize_ipv4_header (&ip4, IPPROTO_UDP, reply_len - off - sizeof (struct GNUNET_TUN_IPv4Header), @@ -471,8 +588,8 @@ request_done (struct RequestRecord *rr) struct sockaddr_in6 *src = (struct sockaddr_in6 *) &rr->src_addr; struct sockaddr_in6 *dst = (struct sockaddr_in6 *) &rr->dst_addr; - spt = dst->sin6_port; - dpt = src->sin6_port; + source_port = dst->sin6_port; + destination_port = src->sin6_port; GNUNET_TUN_initialize_ipv6_header (&ip6, IPPROTO_UDP, reply_len - sizeof (struct GNUNET_TUN_IPv6Header), @@ -490,8 +607,8 @@ request_done (struct RequestRecord *rr) { struct GNUNET_TUN_UdpHeader udp; - udp.spt = spt; - udp.dpt = dpt; + udp.source_port = source_port; + udp.destination_port = destination_port; udp.len = htons (reply_len - off); if (AF_INET == rr->src_addr.ss_family) GNUNET_TUN_calculate_udp4_checksum (&ip4, @@ -514,10 +631,10 @@ request_done (struct RequestRecord *rr) } /* final checks & sending */ GNUNET_assert (off == reply_len); - GNUNET_HELPER_send (hijacker, - hdr, - GNUNET_YES, - NULL, NULL); + (void) GNUNET_HELPER_send (hijacker, + hdr, + GNUNET_YES, + NULL, NULL); GNUNET_STATISTICS_update (stats, gettext_noop ("# DNS requests answered via TUN interface"), 1, GNUNET_NO); @@ -538,7 +655,7 @@ static void send_request_to_client (struct RequestRecord *rr, struct GNUNET_SERVER_Client *client) { - char buf[sizeof (struct GNUNET_DNS_Request) + rr->payload_length]; + char buf[sizeof (struct GNUNET_DNS_Request) + rr->payload_length] GNUNET_ALIGN; struct GNUNET_DNS_Request *req; if (sizeof (buf) >= GNUNET_SERVER_MAX_MESSAGE_SIZE) @@ -560,6 +677,72 @@ send_request_to_client (struct RequestRecord *rr, } +/** + * Read a DNS response from the (unhindered) UDP-Socket + * + * @param cls socket to read from + * @param tc scheduler context (must be shutdown or read ready) + */ +static void +read_response (void *cls, + const struct GNUNET_SCHEDULER_TaskContext *tc); + + +/** + * Get a socket of the specified address family to send out a + * UDP DNS request to the Internet. + * + * @param af desired address family + * @return NULL on error (given AF not "supported") + */ +static struct GNUNET_NETWORK_Handle * +get_request_socket (int af) +{ + struct RequestSocket *rs; + struct GNUNET_NETWORK_FDSet *rset; + static struct GNUNET_NETWORK_Handle *ret; + + rs = &sockets[GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, + DNS_SOCKET_MAX)]; + rs->timeout = GNUNET_TIME_relative_to_absolute (REQUEST_TIMEOUT); + switch (af) + { + case AF_INET: + if (NULL == rs->dnsout4) + rs->dnsout4 = open_socket (AF_INET); + ret = rs->dnsout4; + break; + case AF_INET6: + if (NULL == rs->dnsout6) + rs->dnsout6 = open_socket (AF_INET6); + ret = rs->dnsout6; + break; + default: + return NULL; + } + if (GNUNET_SCHEDULER_NO_TASK != rs->read_task) + { + GNUNET_SCHEDULER_cancel (rs->read_task); + rs->read_task = GNUNET_SCHEDULER_NO_TASK; + } + if ( (NULL == rs->dnsout4) && + (NULL == rs->dnsout6) ) + return NULL; + rset = GNUNET_NETWORK_fdset_create (); + if (NULL != rs->dnsout4) + GNUNET_NETWORK_fdset_set (rset, rs->dnsout4); + if (NULL != rs->dnsout6) + GNUNET_NETWORK_fdset_set (rset, rs->dnsout6); + rs->read_task = GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT, + REQUEST_TIMEOUT, + rset, + NULL, + &read_response, rs); + GNUNET_NETWORK_fdset_destroy (rset); + return ret; +} + + /** * A client has completed its processing for this * request. Move on. @@ -572,7 +755,6 @@ next_phase (struct RequestRecord *rr) struct ClientRecord *cr; int nz; unsigned int j; - struct GNUNET_NETWORK_Handle *dnsout; socklen_t salen; if (rr->phase == RP_DROP) @@ -620,35 +802,34 @@ next_phase (struct RequestRecord *rr) next_phase (rr); return; case RP_QUERY: - rr->phase = RP_INTERNET_DNS; switch (rr->dst_addr.ss_family) { case AF_INET: - dnsout = dnsout4; - salen = sizeof (struct GNUNET_TUN_IPv4Header); + salen = sizeof (struct sockaddr_in); break; case AF_INET6: - dnsout = dnsout6; - salen = sizeof (struct GNUNET_TUN_IPv6Header); + salen = sizeof (struct sockaddr_in6); break; default: - GNUNET_break (0); - cleanup_rr (rr); - return; + GNUNET_assert (0); } - if (NULL == dnsout) + + rr->phase = RP_INTERNET_DNS; + rr->dnsout = get_request_socket (rr->dst_addr.ss_family); + if (NULL == rr->dnsout) { GNUNET_STATISTICS_update (stats, - gettext_noop ("# DNS exit failed (address family not supported)"), + gettext_noop ("# DNS exit failed (failed to open socket)"), 1, GNUNET_NO); cleanup_rr (rr); return; } - GNUNET_NETWORK_socket_sendto (dnsout, + GNUNET_NETWORK_socket_sendto (rr->dnsout, rr->payload, rr->payload_length, (struct sockaddr*) &rr->dst_addr, salen); + rr->timeout = GNUNET_TIME_relative_to_absolute (REQUEST_TIMEOUT); return; case RP_INTERNET_DNS: rr->phase = RP_MODIFY; @@ -776,85 +957,65 @@ transmit_reply_to_mesh (void *cls, /** - * Read a DNS response from the (unhindered) UDP-Socket + * Actually do the reading of a DNS packet from our UDP socket and see + * if we have a valid, matching, pending request. * - * @param cls socket to read from - * @param tc scheduler context (must be shutdown or read ready) + * @param dnsout socket to read from + * @return GNUNET_OK on success, GNUNET_NO on drop, GNUNET_SYSERR on IO-errors (closed socket) */ -static void -read_response (void *cls, - const struct GNUNET_SCHEDULER_TaskContext *tc) +static int +do_dns_read (struct GNUNET_NETWORK_Handle *dnsout) { - struct GNUNET_NETWORK_Handle *dnsout = cls; - struct sockaddr_in addr4; - struct sockaddr_in6 addr6; - struct sockaddr *addr; - struct GNUNET_TUN_DnsHeader *dns; + struct sockaddr_storage addr; socklen_t addrlen; + struct GNUNET_TUN_DnsHeader *dns; struct RequestRecord *rr; struct TunnelState *ts; ssize_t r; int len; - if (dnsout == dnsout4) - { - addrlen = sizeof (struct sockaddr_in); - addr = (struct sockaddr* ) &addr4; - read4_task = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, - dnsout, - &read_response, - dnsout); - } - else - { - addrlen = sizeof (struct sockaddr_in6); - addr = (struct sockaddr* ) &addr6; - read6_task = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, - dnsout, - &read_response, - dnsout); - } - if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)) - return; - #ifndef MINGW if (0 != ioctl (GNUNET_NETWORK_get_fd (dnsout), FIONREAD, &len)) { /* conservative choice: */ - len = 65536; + len = UINT16_MAX; } #else /* port the code above? */ - len = 65536; + len = UINT16_MAX; #endif { - unsigned char buf[len]; + unsigned char buf[len] GNUNET_ALIGN; - memset (addr, 0, addrlen); + addrlen = sizeof (addr); + memset (&addr, 0, sizeof (addr)); r = GNUNET_NETWORK_socket_recvfrom (dnsout, buf, sizeof (buf), - addr, &addrlen); + (struct sockaddr*) &addr, &addrlen); if (-1 == r) { GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "recvfrom"); - return; + GNUNET_NETWORK_socket_close (dnsout); + return GNUNET_SYSERR; } if (sizeof (struct GNUNET_TUN_DnsHeader) > r) { GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _("Received DNS response that is too small (%u bytes)"), r); - return; + return GNUNET_NO; } dns = (struct GNUNET_TUN_DnsHeader *) buf; /* Handle case that this is a reply to a request from a MESH DNS tunnel */ ts = tunnels[dns->id]; if ( (NULL == ts) || + (ts->dnsout != dnsout) || (addrlen != ts->addrlen) || (0 != memcmp (&ts->addr, - addr, - addrlen)) ) + &addr, + addrlen)) || + (0 == GNUNET_TIME_absolute_get_remaining (ts->timeout).rel_value) ) ts = NULL; /* DNS responder address missmatch */ if (NULL != ts) { @@ -875,7 +1036,12 @@ read_response (void *cls, } /* Handle case that this is a reply to a local request (intercepted from TUN interface) */ rr = &requests[dns->id]; - if (rr->phase != RP_INTERNET_DNS) + if ( (rr->phase != RP_INTERNET_DNS) || + (rr->dnsout != dnsout) || + (0 != memcmp (&rr->dst_addr, + &addr, + addrlen)) || + (0 == GNUNET_TIME_absolute_get_remaining (rr->timeout).rel_value) ) { if (NULL == ts) { @@ -884,7 +1050,7 @@ read_response (void *cls, gettext_noop ("# External DNS response discarded (no matching request)"), 1, GNUNET_NO); } - return; + return GNUNET_NO; } GNUNET_free_non_null (rr->payload); rr->payload = GNUNET_malloc (r); @@ -892,122 +1058,52 @@ read_response (void *cls, rr->payload_length = r; next_phase (rr); } -} - - -/** - * Open source port for sending DNS request on IPv4. - * - * @return GNUNET_OK on success - */ -static int -open_port4 () -{ - struct sockaddr_in addr; - socklen_t addrlen; - - dnsout4 = GNUNET_NETWORK_socket_create (AF_INET, SOCK_DGRAM, 0); - if (dnsout4 == NULL) - return GNUNET_SYSERR; - - memset (&addr, 0, sizeof (struct sockaddr_in)); - addr.sin_family = AF_INET; - int err = GNUNET_NETWORK_socket_bind (dnsout4, - (struct sockaddr *) &addr, - sizeof (struct sockaddr_in)); - - if (err != GNUNET_OK) - { - GNUNET_log (GNUNET_ERROR_TYPE_ERROR, - _("Could not bind to any port: %s\n"), - STRERROR (errno)); - GNUNET_NETWORK_socket_close (dnsout4); - dnsout4 = NULL; - return GNUNET_SYSERR; - } - - /* Read the port we bound to */ - addrlen = sizeof (struct sockaddr_in); - if (0 != getsockname (GNUNET_NETWORK_get_fd (dnsout4), - (struct sockaddr *) &addr, - &addrlen)) - { - GNUNET_log (GNUNET_ERROR_TYPE_ERROR, - _("Could not determine port I got: %s\n"), - STRERROR (errno)); - GNUNET_NETWORK_socket_close (dnsout4); - dnsout4 = NULL; - return GNUNET_SYSERR; - } - dnsoutport = htons (addr.sin_port); - - GNUNET_log (GNUNET_ERROR_TYPE_INFO, - _("GNUnet DNS will exit on source port %u\n"), - (unsigned int) dnsoutport); - read4_task = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, - dnsout4, - &read_response, dnsout4); return GNUNET_OK; } /** - * Open source port for sending DNS request on IPv6. Should be - * called AFTER open_port4. + * Read a DNS response from the (unhindered) UDP-Socket * - * @return GNUNET_OK on success - */ -static int -open_port6 () + * @param cls socket to read from + * @param tc scheduler context (must be shutdown or read ready) + */ +static void +read_response (void *cls, + const struct GNUNET_SCHEDULER_TaskContext *tc) { - struct sockaddr_in6 addr; - socklen_t addrlen; + struct RequestSocket *rs = cls; + struct GNUNET_NETWORK_FDSet *rset; - dnsout6 = GNUNET_NETWORK_socket_create (AF_INET6, SOCK_DGRAM, 0); - if (dnsout6 == NULL) - { - GNUNET_log (GNUNET_ERROR_TYPE_ERROR, - _("Could not create IPv6 socket: %s\n"), - STRERROR (errno)); - return GNUNET_SYSERR; - } - memset (&addr, 0, sizeof (struct sockaddr_in6)); - addr.sin6_family = AF_INET6; - addr.sin6_port = htons (dnsoutport); - int err = GNUNET_NETWORK_socket_bind (dnsout6, - (struct sockaddr *) &addr, - sizeof (struct sockaddr_in6)); - - if (err != GNUNET_OK) - { - GNUNET_log (GNUNET_ERROR_TYPE_ERROR, - _("Could not bind to port %u: %s\n"), - (unsigned int) dnsoutport, - STRERROR (errno)); - GNUNET_NETWORK_socket_close (dnsout6); - dnsout6 = NULL; - return GNUNET_SYSERR; - } - if (0 == dnsoutport) + rs->read_task = GNUNET_SCHEDULER_NO_TASK; + if (0 == (tc->reason & GNUNET_SCHEDULER_REASON_READ_READY)) { - addrlen = sizeof (struct sockaddr_in6); - if (0 != getsockname (GNUNET_NETWORK_get_fd (dnsout6), - (struct sockaddr *) &addr, - &addrlen)) - { - GNUNET_log (GNUNET_ERROR_TYPE_ERROR, - _("Could not determine port I got: %s\n"), - STRERROR (errno)); - GNUNET_NETWORK_socket_close (dnsout6); - dnsout6 = NULL; - return GNUNET_SYSERR; - } + /* timeout or shutdown */ + cleanup_rs (rs); + return; } - dnsoutport = htons (addr.sin6_port); - read6_task = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, - dnsout6, - &read_response, dnsout6); - return GNUNET_YES; + /* read and process ready sockets */ + if ((NULL != rs->dnsout4) && + (GNUNET_NETWORK_fdset_isset (tc->read_ready, rs->dnsout4)) && + (GNUNET_SYSERR == do_dns_read (rs->dnsout4))) + rs->dnsout4 = NULL; + if ((NULL != rs->dnsout6) && + (GNUNET_NETWORK_fdset_isset (tc->read_ready, rs->dnsout6)) && + (GNUNET_SYSERR == do_dns_read (rs->dnsout6))) + rs->dnsout6 = NULL; + + /* re-schedule read task */ + rset = GNUNET_NETWORK_fdset_create (); + if (NULL != rs->dnsout4) + GNUNET_NETWORK_fdset_set (rset, rs->dnsout4); + if (NULL != rs->dnsout6) + GNUNET_NETWORK_fdset_set (rset, rs->dnsout6); + rs->read_task = GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_DEFAULT, + GNUNET_TIME_absolute_get_remaining (rs->timeout), + rset, + NULL, + &read_response, rs); + GNUNET_NETWORK_fdset_destroy (rset); } @@ -1100,10 +1196,8 @@ handle_client_response (void *cls GNUNET_UNUSED, return; } GNUNET_free_non_null (rr->payload); -#if DEBUG_DNS GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, - _("Changing DNS reply according to client specifications\n")); -#endif + "Changing DNS reply according to client specifications\n"); rr->payload = GNUNET_malloc (msize); rr->payload_length = msize; memcpy (rr->payload, &resp[1], msize); @@ -1114,6 +1208,16 @@ handle_client_response (void *cls GNUNET_UNUSED, rr->client_wait_list_length, 0); } + /* if query changed to answer, move past DNS resolution phase... */ + if ( (RP_QUERY == rr->phase) && + (rr->payload_length > sizeof (struct GNUNET_TUN_DnsHeader)) && + ((struct GNUNET_DNSPARSER_Flags*)&(((struct GNUNET_TUN_DnsHeader*) rr->payload)->flags))->query_or_response == 1) + { + rr->phase = RP_INTERNET_DNS; + GNUNET_array_grow (rr->client_wait_list, + rr->client_wait_list_length, + 0); + } break; } next_phase (rr); @@ -1135,7 +1239,7 @@ handle_client_response (void *cls GNUNET_UNUSED, * @param client identification of the client * @param message the actual message, a DNS request we should handle */ -static void +static int process_helper_messages (void *cls GNUNET_UNUSED, void *client, const struct GNUNET_MessageHeader *message) { @@ -1156,7 +1260,7 @@ process_helper_messages (void *cls GNUNET_UNUSED, void *client, { /* non-IP packet received on TUN!? */ GNUNET_break (0); - return; + return GNUNET_OK; } msize -= sizeof (struct GNUNET_MessageHeader); tun = (const struct GNUNET_TUN_Layer2PacketHeader *) &message[1]; @@ -1165,6 +1269,7 @@ process_helper_messages (void *cls GNUNET_UNUSED, void *client, { case ETH_P_IPV4: ip4 = (const struct GNUNET_TUN_IPv4Header *) &tun[1]; + ip6 = NULL; /* make compiler happy */ if ( (msize < sizeof (struct GNUNET_TUN_IPv4Header)) || (ip4->version != 4) || (ip4->header_length != sizeof (struct GNUNET_TUN_IPv4Header) / 4) || @@ -1174,12 +1279,13 @@ process_helper_messages (void *cls GNUNET_UNUSED, void *client, /* non-IP/UDP packet received on TUN (or with options) */ GNUNET_log (GNUNET_ERROR_TYPE_INFO, _("Received malformed IPv4-UDP packet on TUN interface.\n")); - return; + return GNUNET_OK; } udp = (const struct GNUNET_TUN_UdpHeader*) &ip4[1]; msize -= sizeof (struct GNUNET_TUN_IPv4Header); break; case ETH_P_IPV6: + ip4 = NULL; /* make compiler happy */ ip6 = (const struct GNUNET_TUN_IPv6Header *) &tun[1]; if ( (msize < sizeof (struct GNUNET_TUN_IPv6Header)) || (ip6->version != 6) || @@ -1189,7 +1295,7 @@ process_helper_messages (void *cls GNUNET_UNUSED, void *client, /* non-IP/UDP packet received on TUN (or with extensions) */ GNUNET_log (GNUNET_ERROR_TYPE_INFO, _("Received malformed IPv6-UDP packet on TUN interface.\n")); - return; + return GNUNET_OK; } udp = (const struct GNUNET_TUN_UdpHeader*) &ip6[1]; msize -= sizeof (struct GNUNET_TUN_IPv6Header); @@ -1200,7 +1306,7 @@ process_helper_messages (void *cls GNUNET_UNUSED, void *client, _("Got non-IP packet with %u bytes and protocol %u from TUN\n"), (unsigned int) msize, ntohs (tun->proto)); - return; + return GNUNET_OK; } if (msize <= sizeof (struct GNUNET_TUN_UdpHeader) + sizeof (struct GNUNET_TUN_DnsHeader)) { @@ -1208,7 +1314,7 @@ process_helper_messages (void *cls GNUNET_UNUSED, void *client, GNUNET_STATISTICS_update (stats, gettext_noop ("# Non-DNS UDP packet received via TUN interface"), 1, GNUNET_NO); - return; + return GNUNET_OK; } msize -= sizeof (struct GNUNET_TUN_UdpHeader); dns = (const struct GNUNET_TUN_DnsHeader*) &udp[1]; @@ -1235,11 +1341,11 @@ process_helper_messages (void *cls GNUNET_UNUSED, void *client, dsta4->sin_family = AF_INET; srca4->sin_addr = ip4->source_address; dsta4->sin_addr = ip4->destination_address; - srca4->sin_port = udp->spt; - dsta4->sin_port = udp->dpt; + srca4->sin_port = udp->source_port; + dsta4->sin_port = udp->destination_port; #if HAVE_SOCKADDR_IN_SIN_LEN - srca4->sin_len = sizeof (sizeof (struct sockaddr_in)); - dsta4->sin_len = sizeof (sizeof (struct sockaddr_in)); + srca4->sin_len = sizeof (struct sockaddr_in); + dsta4->sin_len = sizeof (struct sockaddr_in); #endif } break; @@ -1253,11 +1359,11 @@ process_helper_messages (void *cls GNUNET_UNUSED, void *client, dsta6->sin6_family = AF_INET6; srca6->sin6_addr = ip6->source_address; dsta6->sin6_addr = ip6->destination_address; - srca6->sin6_port = udp->spt; - dsta6->sin6_port = udp->dpt; + srca6->sin6_port = udp->source_port; + dsta6->sin6_port = udp->destination_port; #if HAVE_SOCKADDR_IN_SIN_LEN - srca6->sin6_len = sizeof (sizeof (struct sockaddr_in6)); - dsta6->sin6_len = sizeof (sizeof (struct sockaddr_in6)); + srca6->sin6_len = sizeof (struct sockaddr_in6); + dsta6->sin6_len = sizeof (struct sockaddr_in6); #endif } break; @@ -1275,6 +1381,7 @@ process_helper_messages (void *cls GNUNET_UNUSED, void *client, 1, GNUNET_NO); /* start request processing state machine */ next_phase (rr); + return GNUNET_OK; } @@ -1301,14 +1408,13 @@ receive_dns_request (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel, const struct GNUNET_TUN_DnsHeader *dns; size_t mlen = ntohs (message->size); size_t dlen = mlen - sizeof (struct GNUNET_MessageHeader); - char buf[dlen]; + char buf[dlen] GNUNET_ALIGN; struct GNUNET_TUN_DnsHeader *dout; struct sockaddr_in v4; struct sockaddr_in6 v6; struct sockaddr *so; socklen_t salen; - struct GNUNET_NETWORK_Handle *dnsout; - + if (dlen < sizeof (struct GNUNET_TUN_DnsHeader)) { GNUNET_break_op (0); @@ -1319,15 +1425,13 @@ receive_dns_request (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel, if (tunnels[ts->my_id] == ts) tunnels[ts->my_id] = NULL; ts->my_id = (uint16_t) GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, - 65536); + UINT16_MAX + 1); tunnels[ts->my_id] = ts; memcpy (buf, dns, dlen); dout = (struct GNUNET_TUN_DnsHeader*) buf; dout->id = ts->my_id; - memset (&v4, 0, sizeof (v4)); memset (&v6, 0, sizeof (v6)); - dnsout = NULL; if (1 == inet_pton (AF_INET, dns_exit, &v4.sin_addr)) { salen = sizeof (v4); @@ -1337,9 +1441,9 @@ receive_dns_request (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel, v4.sin_len = (u_char) salen; #endif so = (struct sockaddr *) &v4; - dnsout = dnsout4; - } - if (1 == inet_pton (AF_INET6, dns_exit, &v6.sin6_addr)) + ts->dnsout = get_request_socket (AF_INET); + } + else if (1 == inet_pton (AF_INET6, dns_exit, &v6.sin6_addr)) { salen = sizeof (v6); v6.sin6_family = AF_INET6; @@ -1348,9 +1452,14 @@ receive_dns_request (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel, v6.sin6_len = (u_char) salen; #endif so = (struct sockaddr *) &v6; - dnsout = dnsout6; + ts->dnsout = get_request_socket (AF_INET6); + } + else + { + GNUNET_break (0); + return GNUNET_SYSERR; } - if (NULL == dnsout) + if (NULL == ts->dnsout) { GNUNET_log (GNUNET_ERROR_TYPE_ERROR, _("Configured DNS exit `%s' is not working / valid.\n"), @@ -1361,8 +1470,9 @@ receive_dns_request (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel, so, salen); ts->addrlen = salen; - GNUNET_NETWORK_socket_sendto (dnsout, + GNUNET_NETWORK_socket_sendto (ts->dnsout, buf, dlen, so, salen); + ts->timeout = GNUNET_TIME_relative_to_absolute (REQUEST_TIMEOUT); return GNUNET_OK; } @@ -1435,32 +1545,42 @@ run (void *cls, struct GNUNET_SERVER_Handle *server, {&handle_client_response, NULL, GNUNET_MESSAGE_TYPE_DNS_CLIENT_RESPONSE, 0}, {NULL, NULL, 0, 0} }; - char port_s[6]; char *ifc_name; char *ipv4addr; char *ipv4mask; char *ipv6addr; char *ipv6prefix; + struct in_addr dns_exit4; + struct in6_addr dns_exit6; cfg = cfg_; + if (GNUNET_YES != + GNUNET_OS_check_helper_binary ("gnunet-helper-dns")) + { + GNUNET_log (GNUNET_ERROR_TYPE_ERROR, + _("`%s' must be installed SUID, refusing to run\n"), + "gnunet-helper-dns"); + global_ret = 1; + return; + } + stats = GNUNET_STATISTICS_create ("dns", cfg); nc = GNUNET_SERVER_notification_context_create (server, 1); GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &cleanup_task, cls); - (void) GNUNET_CONFIGURATION_get_value_string (cfg, "dns", - "DNS_EXIT", - &dns_exit); - if (GNUNET_YES == - GNUNET_CONFIGURATION_get_value_yesno (cfg_, "dns", "PROVIDE_EXIT")) + if ( (GNUNET_YES == + GNUNET_CONFIGURATION_get_value_yesno (cfg_, "dns", "PROVIDE_EXIT")) && + ( (GNUNET_OK != + GNUNET_CONFIGURATION_get_value_string (cfg, "dns", + "DNS_EXIT", + &dns_exit)) || + ( (1 != inet_pton (AF_INET, dns_exit, &dns_exit4)) && + (1 != inet_pton (AF_INET6, dns_exit, &dns_exit6)) ) ) ) { - if ( (GNUNET_OK != open_port4 ()) && - (GNUNET_OK != open_port6 ()) ) - { - GNUNET_log (GNUNET_ERROR_TYPE_ERROR, - _("Failed to open any port to provide DNS exit\n")); - GNUNET_SCHEDULER_shutdown (); - return; - } + GNUNET_log (GNUNET_ERROR_TYPE_ERROR, + _("Configured to provide DNS exit, but no valid DNS server configured!\n")); + GNUNET_free_non_null (dns_exit); + dns_exit = NULL; } helper_argv[0] = GNUNET_strdup ("gnunet-dns"); @@ -1514,12 +1634,7 @@ run (void *cls, struct GNUNET_SERVER_Handle *server, return; } helper_argv[5] = ipv4mask; - GNUNET_snprintf (port_s, - sizeof (port_s), - "%u", - (unsigned int) dnsoutport); - helper_argv[6] = GNUNET_strdup (port_s); - helper_argv[7] = NULL; + helper_argv[6] = NULL; if (NULL != dns_exit) { @@ -1559,7 +1674,7 @@ main (int argc, char *const *argv) { return (GNUNET_OK == GNUNET_SERVICE_run (argc, argv, "dns", GNUNET_SERVICE_OPTION_NONE, - &run, NULL)) ? 0 : 1; + &run, NULL)) ? global_ret : 1; }