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- /*
- This file is part of GNUnet.
- Copyright (C) 2010-2015, 2018 GNUnet e.V.
- GNUnet is free software: you can redistribute it and/or modify it
- under the terms of the GNU Affero General Public License as published
- by the Free Software Foundation, either version 3 of the License,
- 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
- Affero General Public License for more details.
- You should have received a copy of the GNU Affero General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>.
- SPDX-License-Identifier: AGPL3.0-or-later
- */
- /**
- * @file nt/nt_api_scanner.c
- * @brief LAN interface scanning to determine IPs in LAN
- * @author Christian Grothoff
- * @author Matthias Wachs
- */
- #include "platform.h"
- #include "gnunet_util_lib.h"
- #include "gnunet_nt_lib.h"
- /**
- * How frequently do we scan the interfaces for changes to the addresses?
- */
- #define INTERFACE_PROCESSING_INTERVAL GNUNET_TIME_relative_multiply ( \
- GNUNET_TIME_UNIT_MINUTES, 2)
- /**
- * Convert a `enum GNUNET_NetworkType` to a string
- *
- * @param net the network type
- * @return a string or NULL if invalid
- */
- const char *
- GNUNET_NT_to_string (enum GNUNET_NetworkType net)
- {
- switch (net)
- {
- case GNUNET_NT_UNSPECIFIED:
- return "UNSPECIFIED";
- case GNUNET_NT_LOOPBACK:
- return "LOOPBACK";
- case GNUNET_NT_LAN:
- return "LAN";
- case GNUNET_NT_WAN:
- return "WAN";
- case GNUNET_NT_WLAN:
- return "WLAN";
- case GNUNET_NT_BT:
- return "BLUETOOTH";
- default:
- return NULL;
- }
- }
- /**
- * We keep a list of our local networks so we can answer
- * LAN vs. WAN questions. Note: WLAN is not detected yet.
- * (maybe we can do that heuristically based on interface
- * name in the future?).
- */
- struct NT_Network
- {
- /**
- * Kept in a DLL.
- */
- struct NT_Network *next;
- /**
- * Kept in a DLL.
- */
- struct NT_Network *prev;
- /**
- * Network address.
- */
- struct sockaddr *network;
- /**
- * Netmask to determine what is in the LAN.
- */
- struct sockaddr *netmask;
- /**
- * How long are @e network and @e netmask?
- */
- socklen_t length;
- };
- /**
- * Handle to the interface scanner.
- */
- struct GNUNET_NT_InterfaceScanner
- {
- /**
- * Head of LAN networks list.
- */
- struct NT_Network *net_head;
- /**
- * Tail of LAN networks list.
- */
- struct NT_Network *net_tail;
- /**
- * Task for periodically refreshing our LAN network list.
- */
- struct GNUNET_SCHEDULER_Task *interface_task;
- };
- /**
- * Delete all entries from the current network list.
- *
- * @param is scanner to clean up
- */
- static void
- delete_networks (struct GNUNET_NT_InterfaceScanner *is)
- {
- struct NT_Network *cur;
- while (NULL != (cur = is->net_head))
- {
- GNUNET_CONTAINER_DLL_remove (is->net_head,
- is->net_tail,
- cur);
- GNUNET_free (cur);
- }
- }
- /**
- * Function invoked for each interface found. Adds the interface's
- * network addresses to the respective DLL, so we can distinguish
- * between LAN and WAN.
- *
- * @param cls closure with the `struct GNUNET_NT_InterfaceScanner`
- * @param name name of the interface (can be NULL for unknown)
- * @param isDefault is this presumably the default interface
- * @param addr address of this interface (can be NULL for unknown or unassigned)
- * @param broadcast_addr the broadcast address (can be NULL for unknown or unassigned)
- * @param netmask the network mask (can be NULL for unknown or unassigned)
- * @param addrlen length of the address
- * @return #GNUNET_OK to continue iteration
- */
- static int
- interface_proc (void *cls,
- const char *name,
- int isDefault,
- const struct sockaddr *addr,
- const struct sockaddr *broadcast_addr,
- const struct sockaddr *netmask,
- socklen_t addrlen)
- {
- struct GNUNET_NT_InterfaceScanner *is = cls;
- /* Calculate network */
- struct NT_Network *net = NULL;
- (void) name;
- (void) isDefault;
- (void) broadcast_addr;
- /* Skipping IPv4 loopback addresses since we have special check */
- if (addr->sa_family == AF_INET)
- {
- const struct sockaddr_in *a4 = (const struct sockaddr_in *) addr;
- if ((a4->sin_addr.s_addr & htonl (0xff000000)) == htonl (0x7f000000))
- return GNUNET_OK;
- }
- /* Skipping IPv6 loopback addresses since we have special check */
- if (addr->sa_family == AF_INET6)
- {
- const struct sockaddr_in6 *a6 = (const struct sockaddr_in6 *) addr;
- if (IN6_IS_ADDR_LOOPBACK (&a6->sin6_addr))
- return GNUNET_OK;
- }
- if (addr->sa_family == AF_INET)
- {
- const struct sockaddr_in *addr4 = (const struct sockaddr_in *) addr;
- const struct sockaddr_in *netmask4 = (const struct sockaddr_in *) netmask;
- struct sockaddr_in *tmp;
- struct sockaddr_in network4;
- net = GNUNET_malloc (sizeof(struct NT_Network) + 2 * sizeof(struct
- sockaddr_in));
- tmp = (struct sockaddr_in *) &net[1];
- net->network = (struct sockaddr *) &tmp[0];
- net->netmask = (struct sockaddr *) &tmp[1];
- net->length = addrlen;
- memset (&network4,
- 0,
- sizeof(network4));
- network4.sin_family = AF_INET;
- #if HAVE_SOCKADDR_IN_SIN_LEN
- network4.sin_len = sizeof(network4);
- #endif
- network4.sin_addr.s_addr = (addr4->sin_addr.s_addr
- & netmask4->sin_addr.s_addr);
- GNUNET_memcpy (net->netmask,
- netmask4,
- sizeof(struct sockaddr_in));
- GNUNET_memcpy (net->network,
- &network4,
- sizeof(struct sockaddr_in));
- }
- if (addr->sa_family == AF_INET6)
- {
- const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *) addr;
- const struct sockaddr_in6 *netmask6 = (const struct sockaddr_in6 *) netmask;
- struct sockaddr_in6 *tmp;
- struct sockaddr_in6 network6;
- net = GNUNET_malloc (sizeof(struct NT_Network) + 2 * sizeof(struct
- sockaddr_in6));
- tmp = (struct sockaddr_in6 *) &net[1];
- net->network = (struct sockaddr *) &tmp[0];
- net->netmask = (struct sockaddr *) &tmp[1];
- net->length = addrlen;
- memset (&network6, 0, sizeof(network6));
- network6.sin6_family = AF_INET6;
- #if HAVE_SOCKADDR_IN_SIN_LEN
- network6.sin6_len = sizeof(network6);
- #endif
- unsigned int c = 0;
- uint32_t *addr_elem = (uint32_t *) &addr6->sin6_addr;
- uint32_t *mask_elem = (uint32_t *) &netmask6->sin6_addr;
- uint32_t *net_elem = (uint32_t *) &network6.sin6_addr;
- for (c = 0; c < 4; c++)
- net_elem[c] = addr_elem[c] & mask_elem[c];
- GNUNET_memcpy (net->netmask,
- netmask6,
- sizeof(struct sockaddr_in6));
- GNUNET_memcpy (net->network,
- &network6,
- sizeof(struct sockaddr_in6));
- }
- if (NULL == net)
- return GNUNET_OK; /* odd / unsupported address family */
- /* Store in list */
- #if VERBOSE_NT
- char *netmask = GNUNET_strdup (GNUNET_a2s ((struct sockaddr *) net->netmask,
- addrlen));
- GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
- "nt",
- "Adding network `%s', netmask `%s'\n",
- GNUNET_a2s ((struct sockaddr *) net->network,
- addrlen),
- netmask);
- GNUNET_free (netmask);
- #endif
- GNUNET_CONTAINER_DLL_insert (is->net_head,
- is->net_tail,
- net);
- return GNUNET_OK;
- }
- /**
- * Periodically get list of network addresses from our interfaces.
- *
- * @param cls closure
- */
- static void
- get_addresses (void *cls)
- {
- struct GNUNET_NT_InterfaceScanner *is = cls;
- is->interface_task = NULL;
- delete_networks (is);
- GNUNET_OS_network_interfaces_list (&interface_proc,
- is);
- is->interface_task = GNUNET_SCHEDULER_add_delayed (
- INTERFACE_PROCESSING_INTERVAL,
- &get_addresses,
- is);
- }
- /**
- * Returns where the address is located: LAN or WAN or ...
- *
- * @param is the interface scanner handle
- * @param addr address
- * @param addrlen address length
- * @return type of the network the address belongs to
- */
- enum GNUNET_NetworkType
- GNUNET_NT_scanner_get_type (struct GNUNET_NT_InterfaceScanner *is,
- const struct sockaddr *addr,
- socklen_t addrlen)
- {
- struct NT_Network *cur = is->net_head;
- enum GNUNET_NetworkType type = GNUNET_NT_UNSPECIFIED;
- switch (addr->sa_family)
- {
- case AF_UNIX:
- type = GNUNET_NT_LOOPBACK;
- break;
- case AF_INET:
- {
- const struct sockaddr_in *a4 = (const struct sockaddr_in *) addr;
- if ((a4->sin_addr.s_addr & htonl (0xff000000)) == htonl (0x7f000000))
- type = GNUNET_NT_LOOPBACK;
- break;
- }
- case AF_INET6:
- {
- const struct sockaddr_in6 *a6 = (const struct sockaddr_in6 *) addr;
- if (IN6_IS_ADDR_LOOPBACK (&a6->sin6_addr))
- type = GNUNET_NT_LOOPBACK;
- break;
- }
- default:
- GNUNET_break (0);
- break;
- }
- /* Check local networks */
- while ((NULL != cur) && (GNUNET_NT_UNSPECIFIED == type))
- {
- if (addrlen != cur->length)
- {
- cur = cur->next;
- continue;
- }
- if (addr->sa_family == AF_INET)
- {
- const struct sockaddr_in *a4 = (const struct sockaddr_in *) addr;
- const struct sockaddr_in *net4 = (const struct
- sockaddr_in *) cur->network;
- const struct sockaddr_in *mask4 = (const struct
- sockaddr_in *) cur->netmask;
- if (((a4->sin_addr.s_addr & mask4->sin_addr.s_addr)) ==
- net4->sin_addr.s_addr)
- type = GNUNET_NT_LAN;
- }
- if (addr->sa_family == AF_INET6)
- {
- const struct sockaddr_in6 *a6 = (const struct sockaddr_in6 *) addr;
- const struct sockaddr_in6 *net6 = (const struct
- sockaddr_in6 *) cur->network;
- const struct sockaddr_in6 *mask6 = (const struct
- sockaddr_in6 *) cur->netmask;
- int res = GNUNET_YES;
- int c = 0;
- uint32_t *addr_elem = (uint32_t *) &a6->sin6_addr;
- uint32_t *mask_elem = (uint32_t *) &mask6->sin6_addr;
- uint32_t *net_elem = (uint32_t *) &net6->sin6_addr;
- for (c = 0; c < 4; c++)
- if ((addr_elem[c] & mask_elem[c]) != net_elem[c])
- res = GNUNET_NO;
- if (res == GNUNET_YES)
- type = GNUNET_NT_LAN;
- }
- cur = cur->next;
- }
- /* no local network found for this address, default: WAN */
- if (type == GNUNET_NT_UNSPECIFIED)
- type = GNUNET_NT_WAN;
- GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
- "nt-scanner-api",
- "`%s' is in network `%s'\n",
- GNUNET_a2s (addr,
- addrlen),
- GNUNET_NT_to_string (type));
- return type;
- }
- /**
- * Initialize the interface scanner.
- *
- * @return interface scanner
- */
- struct GNUNET_NT_InterfaceScanner *
- GNUNET_NT_scanner_init ()
- {
- struct GNUNET_NT_InterfaceScanner *is;
- is = GNUNET_new (struct GNUNET_NT_InterfaceScanner);
- GNUNET_OS_network_interfaces_list (&interface_proc,
- is);
- is->interface_task = GNUNET_SCHEDULER_add_delayed (
- INTERFACE_PROCESSING_INTERVAL,
- &get_addresses,
- is);
- return is;
- }
- /**
- * Client is done with the interface scanner, release resources.
- *
- * @param is handle to release
- */
- void
- GNUNET_NT_scanner_done (struct GNUNET_NT_InterfaceScanner *is)
- {
- if (NULL != is->interface_task)
- {
- GNUNET_SCHEDULER_cancel (is->interface_task);
- is->interface_task = NULL;
- }
- delete_networks (is);
- GNUNET_free (is);
- }
- /* end of nt.c */
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