diff options
Diffstat (limited to 'src/dns/dns_api.c')
| -rw-r--r-- | src/dns/dns_api.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/src/dns/dns_api.c b/src/dns/dns_api.c new file mode 100644 index 0000000000..90b4a8f42f --- /dev/null +++ b/src/dns/dns_api.c @@ -0,0 +1,263 @@ +/* + This file is part of GNUnet. + (C) 2010 Christian Grothoff + + GNUnet is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published + by the Free Software Foundation; either version 3, or (at your + option) any later version. + + GNUnet is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with GNUnet; see the file COPYING. If not, write to the + Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. +*/ + +/** + * @file vpn/gnunet-daemon-vpn-dns.c + * @brief + * @author Philipp Toelke + */ +#include <platform.h> +#include <gnunet_common.h> +#include <gnunet_client_lib.h> +#include <gnunet_os_lib.h> +#include <gnunet_mesh_service.h> +#include <gnunet_protocols.h> +#include <gnunet_server_lib.h> +#include <gnunet_container_lib.h> +#include <block_dns.h> + +#include "gnunet_dns_service.h" + + +struct GNUNET_DNS_Handle +{ + struct query_packet_list *head; + struct query_packet_list *tail; + struct GNUNET_CLIENT_Connection *dns_connection; + unsigned char restart_hijack; + + struct GNUNET_CLIENT_TransmitHandle *dns_transmit_handle; + + const struct GNUNET_CONFIGURATION_Handle *cfg; + + GNUNET_SCHEDULER_Task process_answer_cb; + + void *process_answer_cb_cls; +}; + + +/** + * Callback called by notify_transmit_ready; sends dns-queries or rehijack-messages + * to the service-dns + * {{{ + */ +size_t +send_query (void *cls GNUNET_UNUSED, size_t size, void *buf) +{ + struct GNUNET_DNS_Handle *h = cls; + + size_t len; + + h->dns_transmit_handle = NULL; + + /* + * Send the rehijack-message + */ + if (h->restart_hijack == 1) + { + h->restart_hijack = 0; + /* + * The message is just a header + */ + GNUNET_assert (sizeof (struct GNUNET_MessageHeader) <= size); + struct GNUNET_MessageHeader *hdr = buf; + + len = sizeof (struct GNUNET_MessageHeader); + hdr->size = htons (len); + hdr->type = htons (GNUNET_MESSAGE_TYPE_REHIJACK); + } + else if (h->head != NULL) + { + struct query_packet_list *query = h->head; + + len = ntohs (query->pkt.hdr.size); + + GNUNET_assert (len <= size); + + memcpy (buf, &query->pkt.hdr, len); + + GNUNET_CONTAINER_DLL_remove (h->head, h->tail, query); + + GNUNET_free (query); + } + else + { + GNUNET_break (0); + len = 0; + } + + /* + * Check whether more data is to be sent + */ + if (h->head != NULL) + { + h->dns_transmit_handle = + GNUNET_CLIENT_notify_transmit_ready (h->dns_connection, + ntohs (h->head->pkt.hdr.size), + GNUNET_TIME_UNIT_FOREVER_REL, + GNUNET_YES, &send_query, h); + } + else if (h->restart_hijack == 1) + { + h->dns_transmit_handle = + GNUNET_CLIENT_notify_transmit_ready (h->dns_connection, + sizeof (struct + GNUNET_MessageHeader), + GNUNET_TIME_UNIT_FOREVER_REL, + GNUNET_YES, &send_query, h); + } + + return len; +} + +/* }}} */ + + + +/** + * This receives packets from the service-dns and schedules process_answer to + * handle it + */ +static void +dns_answer_handler (void *cls, + const struct GNUNET_MessageHeader *msg) +{ + struct GNUNET_DNS_Handle *h = cls; + + /* the service disconnected, reconnect after short wait */ + if (msg == NULL) + { + if (h->dns_transmit_handle != NULL) + GNUNET_CLIENT_notify_transmit_ready_cancel (h->dns_transmit_handle); + h->dns_transmit_handle = NULL; + GNUNET_CLIENT_disconnect (h->dns_connection, GNUNET_NO); + h->dns_connection = NULL; +#if 0 + h->conn_task = + GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS, + &connect_to_service_dns, h); +#endif + return; + } + + /* the service did something strange, reconnect immediately */ + if (msg->type != htons (GNUNET_MESSAGE_TYPE_VPN_DNS_LOCAL_RESPONSE_DNS)) + { + GNUNET_break (0); + GNUNET_CLIENT_disconnect (h->dns_connection, GNUNET_NO); + h->dns_connection = NULL; +#if 0 + conn_task = GNUNET_SCHEDULER_add_now (&connect_to_service_dns, NULL); +#endif + return; + } + void *pkt = GNUNET_malloc (ntohs (msg->size)); + + memcpy (pkt, msg, ntohs (msg->size)); + + GNUNET_SCHEDULER_add_now (h->process_answer_cb, pkt); + GNUNET_CLIENT_receive (h->dns_connection, &dns_answer_handler, h, + GNUNET_TIME_UNIT_FOREVER_REL); +} + + +/** + * Connect to the service-dns + */ +struct GNUNET_DNS_Handle * +GNUNET_DNS_connect (const struct GNUNET_CONFIGURATION_Handle *cfg, + GNUNET_SCHEDULER_Task cb, + void *cb_cls) +{ + struct GNUNET_DNS_Handle *h; + + h = GNUNET_malloc (sizeof (struct GNUNET_DNS_Handle)); + h->cfg = cfg; + h->process_answer_cb = cb; + h->process_answer_cb_cls = cb_cls; + GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Connecting to service-dns\n"); + h->dns_connection = GNUNET_CLIENT_connect ("dns", h->cfg); + /* This would most likely be a misconfiguration */ + GNUNET_assert (NULL != h->dns_connection); + GNUNET_CLIENT_receive (h->dns_connection, + &dns_answer_handler, NULL, + GNUNET_TIME_UNIT_FOREVER_REL); + /* If a packet is already in the list, schedule to send it */ + if (h->dns_transmit_handle == NULL && h->head != NULL) + h->dns_transmit_handle = + GNUNET_CLIENT_notify_transmit_ready (h->dns_connection, + ntohs (h->head->pkt.hdr.size), + GNUNET_TIME_UNIT_FOREVER_REL, + GNUNET_YES, &send_query, h); + else if (h->dns_transmit_handle == NULL && h->restart_hijack == 1) + { + h->dns_transmit_handle = + GNUNET_CLIENT_notify_transmit_ready (h->dns_connection, + sizeof (struct + GNUNET_MessageHeader), + GNUNET_TIME_UNIT_FOREVER_REL, + GNUNET_YES, &send_query, NULL); + } + return h; +} + + +void +GNUNET_DNS_restart_hijack (struct GNUNET_DNS_Handle *h) +{ + h->restart_hijack = 1; + if (NULL != h->dns_connection && h->dns_transmit_handle == NULL) + h->dns_transmit_handle = + GNUNET_CLIENT_notify_transmit_ready (h->dns_connection, + sizeof (struct + GNUNET_MessageHeader), + GNUNET_TIME_UNIT_FOREVER_REL, + GNUNET_YES, &send_query, h); +} + + +/** + * FIXME: we should not expost our internal structures like this. + * Just a quick initial hack. + */ +void +GNUNET_DNS_queue_request (struct GNUNET_DNS_Handle *h, + struct query_packet_list *q) +{ + GNUNET_CONTAINER_DLL_insert_tail (h->head, h->tail, q); + if (h->dns_connection != NULL && h->dns_transmit_handle == NULL) + h->dns_transmit_handle = + GNUNET_CLIENT_notify_transmit_ready (h->dns_connection, ntohs(q->pkt.hdr.size), + GNUNET_TIME_UNIT_FOREVER_REL, + GNUNET_YES, &send_query, + h); +} + + +void +GNUNET_DNS_disconnect (struct GNUNET_DNS_Handle *h) +{ + if (h->dns_connection != NULL) + { + GNUNET_CLIENT_disconnect (h->dns_connection, GNUNET_NO); + h->dns_connection = NULL; + } + GNUNET_free (h); +} |