configd-963.200.27.tar.gz

[apple/configd.git] / nwi / network_information.c

/*
 * Copyright (c) 2011-2018 Apple Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_LICENSE_HEADER_END@
 */


#include <pthread.h>
#include <notify.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/socket.h>
#include <dispatch/dispatch.h>
#ifdef  VERBOSE_ACTIVITY_LOGGING
#include <os/activity.h>
#endif  // VERBOSE_ACTIVITY_LOGGING
#include <os/log.h>
#include <xpc/xpc.h>

#include "libSystemConfiguration_client.h"
#include "network_information.h"
#include "network_state_information_priv.h"

#if !TARGET_OS_SIMULATOR
#include "network_config_agent_info_priv.h"
#include "configAgentDefines.h"
#endif // !TARGET_OS_SIMULATOR

static nwi_state_t      G_nwi_state             = NULL;
static pthread_mutex_t  nwi_store_lock          = PTHREAD_MUTEX_INITIALIZER;
static boolean_t        nwi_store_token_valid   = FALSE;

static pthread_once_t   initialized             = PTHREAD_ONCE_INIT;
static int              nwi_store_token;

static boolean_t        nwi_store_force_refresh = FALSE;
static const char *     client_proc_name = NULL;

#pragma mark -
#pragma mark Network information [nwi] client support


// Note: protected by __nwi_client_queue()
static int                      nwi_active      = 0;
static libSC_info_client_t      *nwi_client     = NULL;


#ifdef  VERBOSE_ACTIVITY_LOGGING
static os_activity_t
__nwi_client_activity()
{
        static os_activity_t    activity;
        static dispatch_once_t  once;

        dispatch_once(&once, ^{
                activity = os_activity_create("accessing network information",
                                              OS_ACTIVITY_CURRENT,
                                              OS_ACTIVITY_FLAG_DEFAULT);
        });

        return activity;
}
#endif  // VERBOSE_ACTIVITY_LOGGING


static dispatch_queue_t
__nwi_client_queue()
{
        static dispatch_once_t  once;
        static dispatch_queue_t q;

        dispatch_once(&once, ^{
                q = dispatch_queue_create(NWI_SERVICE_NAME, NULL);
        });

        return q;
}

static
void
_nwi_state_initialize(void)
{
        const char      *nwi_key        = nwi_state_get_notify_key();
        uint32_t        status          = notify_register_check(nwi_key,
                                                                &nwi_store_token);

        if (status != NOTIFY_STATUS_OK) {
                fprintf(stderr, "nwi_state: registration failed (%u)\n", status);
        }
        else {
                nwi_store_token_valid = TRUE;
        }
}

#pragma mark -
#pragma mark Network information [nwi] APIs


/*
 * Function: nwi_state_get_notify_key
 * Purpose:
 *   Returns the BSD notify key to use to monitor when the state changes.
 *
 * Note:
 *   The nwi_state_copy API uses this notify key to monitor when the state
 *   changes, so each invocation of nwi_state_copy returns the current
 *   information.
 */
const char *
nwi_state_get_notify_key()
{
        return "com.apple.system.SystemConfiguration.nwi";
}

#define ATOMIC_CMPXCHG(p, o, n) __sync_bool_compare_and_swap((p), (o), (n))
#define ATOMIC_INC(p)           __sync_fetch_and_add((p), 1)            // return (n++);
#define ATOMIC_DEC(p)           __sync_sub_and_fetch((p), 1)            // return (--n);

void
_nwi_state_force_refresh()
{
        ATOMIC_CMPXCHG(&nwi_store_force_refresh, FALSE, TRUE);
}

static void
nwi_state_retain(nwi_state_t state)
{
        ATOMIC_INC(&state->ref);
        return;
}

static void
_nwi_client_release()
{
        // release connection reference on 1-->0 transition
        dispatch_sync(__nwi_client_queue(), ^{
                if (--nwi_active == 0) {
                        // if last reference, drop connection
                        libSC_info_client_release(nwi_client);
                        nwi_client = NULL;
                }
        });
}

static void
_nwi_client_init()
{
        dispatch_sync(__nwi_client_queue(), ^{
                if ((nwi_active++ == 0) || (nwi_client == NULL)) {
                        static dispatch_once_t  once;
                        static const char       *service_name   = NWI_SERVICE_NAME;

                        dispatch_once(&once, ^{
#if     DEBUG
                                const char      *name;

                                // get [XPC] service name
                                name = getenv(service_name);
                                if (name != NULL) {
                                        service_name = strdup(name);
                                }
#endif  // DEBUG

                                // get process name
                                client_proc_name = getprogname();
                        });

                        nwi_client =
                        libSC_info_client_create(__nwi_client_queue(),  // dispatch queue
                                                 service_name,                  // XPC service name
                                                 "Network information");        // service description
                        if (nwi_client == NULL) {
                                --nwi_active;
                        }
                }
        });
}

/*
 * Function: nwi_state_release
 * Purpose:
 *   Release the memory associated with the network state.
 */
void
nwi_state_release(nwi_state_t state)
{
        if (ATOMIC_DEC(&state->ref) > 0) {
                // if not last reference
                return;
        }

        _nwi_client_release();

        // release nwi_state
        nwi_state_free(state);

        return;
}

static nwi_state *
_nwi_state_copy_data()
{
        nwi_state_t             nwi_state       = NULL;
        xpc_object_t            reqdict;
        xpc_object_t            reply;

        if (!libSC_info_available()) {
                os_log(OS_LOG_DEFAULT, "*** network information requested between fork() and exec()");
                return NULL;
        }

        _nwi_client_init();

        if ((nwi_client == NULL) || !nwi_client->active) {
                // if network information server not available
                return NULL;
        }

#ifdef  VERBOSE_ACTIVITY_LOGGING
        // scope NWI activity
        os_activity_scope(__nwi_client_activity());
#endif  // VERBOSE_ACTIVITY_LOGGING

        // create message
        reqdict = xpc_dictionary_create(NULL, NULL, 0);

        // set process name
        if (client_proc_name != NULL) {
                xpc_dictionary_set_string(reqdict, NWI_PROC_NAME, client_proc_name);
        }

        // set request
        xpc_dictionary_set_int64(reqdict, NWI_REQUEST, NWI_STATE_REQUEST_COPY);

        // send request to the DNS configuration server
        reply = libSC_send_message_with_reply_sync(nwi_client, reqdict);
        xpc_release(reqdict);

        if (reply != NULL) {
                const void      *dataRef;
                size_t          dataLen = 0;

                dataRef = xpc_dictionary_get_data(reply, NWI_CONFIGURATION, &dataLen);
                if (dataRef != NULL) {
                        nwi_state = malloc(dataLen);
                        bcopy((void *)dataRef, nwi_state, dataLen);
                        if (nwi_state->version != NWI_STATE_VERSION) {
                                /* make sure the version matches */
                                nwi_state_free(nwi_state);
                                nwi_state = NULL;
                        }
                        else {
                                nwi_state->ref = 0;
                        }
                }

                xpc_release(reply);
        }

        return nwi_state;
}

#if !TARGET_OS_SIMULATOR
/*
 * Function: _nwi_config_agent_copy_data
 * Purpose:
 *   Copy the config agent data and the data length.
 *   Caller must free the buffer.
 */
const void *
_nwi_config_agent_copy_data(const struct netagent *agent, uint64_t *length)
{
        const void      *buffer = NULL;
        xpc_object_t    reqdict;
        xpc_object_t    reply;

        if ((agent == NULL) || (length == NULL)) {
                return NULL;
        }

        _nwi_client_init();

#ifdef  VERBOSE_ACTIVITY_LOGGING
        // scope NWI activity
        os_activity_scope(__nwi_client_activity());
#endif  // VERBOSE_ACTIVITY_LOGGING

        reqdict = xpc_dictionary_create(NULL, NULL, 0);

        xpc_dictionary_set_int64(reqdict, NWI_REQUEST, NWI_CONFIG_AGENT_REQUEST_COPY);
        if (client_proc_name != NULL) {
                xpc_dictionary_set_string(reqdict, NWI_PROC_NAME, client_proc_name);
        }

        xpc_dictionary_set_uuid(reqdict, kConfigAgentAgentUUID, agent->netagent_uuid);
        xpc_dictionary_set_string(reqdict, kConfigAgentType, agent->netagent_type);

        // send request to the NWI configuration server
        reply = libSC_send_message_with_reply_sync(nwi_client, reqdict);
        xpc_release(reqdict);

        if (reply != NULL) {
                const void      *xpc_buffer     = NULL;
                unsigned long   len             = 0;

                xpc_buffer = xpc_dictionary_get_data(reply, kConfigAgentAgentData, &len);
                if ((xpc_buffer != NULL) && (len > 0)) {
                        buffer = malloc(len);
                        *length = len;
                        bcopy((void *)xpc_buffer, (void *)buffer, len);
                }
                xpc_release(reply);
        }

        _nwi_client_release();

        return buffer;
}
#endif // !TARGET_OS_SIMULATOR

/*
 * Function: nwi_state_copy
 * Purpose:
 *   Returns the current network state information.
 *   Release after use by calling nwi_state_release().
 */
nwi_state_t
nwi_state_copy(void)
{
        boolean_t       force_refresh;
        nwi_state_t     nwi_state = NULL;
        nwi_state_t     old_state = NULL;

        pthread_once(&initialized, _nwi_state_initialize);
        pthread_mutex_lock(&nwi_store_lock);

        force_refresh = ATOMIC_CMPXCHG(&nwi_store_force_refresh, TRUE, FALSE);

        if (G_nwi_state != NULL) {
                int             check = 0;
                uint32_t        status;

                if (!nwi_store_token_valid) {
                        /* have to throw cached copy away every time */
                        check = 1;
                }
                else {
                        status = notify_check(nwi_store_token, &check);
                        if (status != NOTIFY_STATUS_OK) {
                                fprintf(stderr, "nwi notify_check: failed with %u\n",
                                        status);
                                /* assume that it changed, throw cached copy away */
                                check = 1;
                        }
                }
                if (check != 0 || force_refresh) {
                        /* new need snapshot */
                        old_state = G_nwi_state;
                        G_nwi_state = NULL;
                }
        }
        /* Let's populate the cache if it's empty */
        if (G_nwi_state == NULL) {
                G_nwi_state = _nwi_state_copy_data();
                if (G_nwi_state != NULL) {
                        /* one reference for G_nwi_state */
                        nwi_state_retain(G_nwi_state);
                }
        }
        if (G_nwi_state != NULL) {
                /* another reference for this caller */
                nwi_state_retain(G_nwi_state);
        }
        nwi_state = G_nwi_state;
        pthread_mutex_unlock(&nwi_store_lock);

        if (old_state != NULL) {
                /* get rid of G_nwi_state reference */
                nwi_state_release(old_state);
        }
        return nwi_state;
}

/*
 * Function: _nwi_state_ack
 * Purpose:
 *   Acknowledge receipt and any changes associated with the [new or
 *   updated] network state.
 */
void
_nwi_state_ack(nwi_state_t state, const char *bundle_id)
{
#pragma unused(bundle_id)
        xpc_object_t    reqdict;

        if (state == NULL) {
                return; // ASSERT
        }

        if ((nwi_client == NULL) || !nwi_client->active) {
                // if network information server not available
                return;
        }

        dispatch_sync(__nwi_client_queue(), ^{
                nwi_active++;   // keep connection active (for the life of the process)
        });

        // create message
        reqdict = xpc_dictionary_create(NULL, NULL, 0);

        // set request
        xpc_dictionary_set_int64(reqdict, NWI_REQUEST, NWI_STATE_REQUEST_ACKNOWLEDGE);

        // set generation
        xpc_dictionary_set_uint64(reqdict, NWI_GENERATION, state->generation_count);

        // send acknowledgement to the DNS configuration server
        xpc_connection_send_message(nwi_client->connection, reqdict);

        xpc_release(reqdict);
        return;
}

/*
 * Function: nwi_state_get_generation
 * Purpose:
 *   Returns the generation (mach_time) of the nwi_state data.
 *   Every time the data is updated due to changes
 *   in the network, this value will change.
 */
uint64_t
nwi_state_get_generation(nwi_state_t state)
{
        return (state->generation_count);
}

/*
 * Function: nwi_ifstate_get_generation
 * Purpose:
 *   Returns the generation (mach_time) of the nwi_ifstate data.
 */
uint64_t
nwi_ifstate_get_generation(nwi_ifstate_t ifstate)
{
        return (ifstate->if_generation_count);
}

/*
 * Function: nwi_ifstate_get_ifname
 * Purpose:
 *   Return the interface name of the specified ifstate.
 */
const char *
nwi_ifstate_get_ifname(nwi_ifstate_t ifstate)
{
        return ((ifstate != NULL) ? ifstate->ifname : NULL);
}

static uint64_t
flags_from_af(int af)
{
    return ((af == AF_INET)
            ? NWI_IFSTATE_FLAGS_HAS_IPV4
            : NWI_IFSTATE_FLAGS_HAS_IPV6);
}
/*
 * Function: nwi_ifstate_get_flags
 * Purpose:
 *   Return the flags for the given ifstate (see above for bit definitions).
 */
nwi_ifstate_flags
nwi_ifstate_get_flags(nwi_ifstate_t ifstate)
{
        nwi_ifstate_t           alias = NULL;
        nwi_ifstate_flags       flags = 0ULL;

        if (ifstate->af_alias_offset != 0) {
                alias = ifstate + ifstate->af_alias_offset;
        }
        flags |= flags_from_af(ifstate->af);
        if ((ifstate->flags & NWI_IFSTATE_FLAGS_HAS_DNS) != 0) {
                flags |= NWI_IFSTATE_FLAGS_HAS_DNS;
        }
        if ((ifstate->flags & NWI_IFSTATE_FLAGS_HAS_CLAT46) != 0) {
                flags |= NWI_IFSTATE_FLAGS_HAS_CLAT46;
        }
        if (alias != NULL) {
                flags |= flags_from_af(alias->af);
                if ((alias->flags & NWI_IFSTATE_FLAGS_HAS_DNS) != 0) {
                        flags |= NWI_IFSTATE_FLAGS_HAS_DNS;
                }
                if ((alias->flags & NWI_IFSTATE_FLAGS_HAS_CLAT46) != 0) {
                        flags |= NWI_IFSTATE_FLAGS_HAS_CLAT46;
                }
        }
        return flags;
}

/*
 * Function: nwi_state_get_first_ifstate
 * Purpose:
 *   Returns the first and highest priority interface that has connectivity
 *   for the specified address family 'af'. 'af' is either AF_INET or AF_INET6.
 *   The connectivity provided is for general networking.   To get information
 *   about an interface that isn't available for general networking, use
 *   nwi_state_get_ifstate().
 *
 *   Use nwi_ifstate_get_next() to get the next, lower priority interface
 *   in the list.
 *
 *   Returns NULL if no connectivity for the specified address family is
 *   available.
 */
nwi_ifstate_t
nwi_state_get_first_ifstate(nwi_state_t state, int af)
{
        nwi_ifstate_t ifstate;

        if (state == NULL) {
                return NULL;
        }

        ifstate = nwi_state_get_ifstate_with_index(state, af, 0);
        if (ifstate == NULL) {
                return NULL;
        }
        if ((ifstate->flags & NWI_IFSTATE_FLAGS_NOT_IN_LIST)
            != 0) {
                ifstate = NULL;
        }

        return ifstate;

}

/*
 * Function: nwi_state_get_ifstate
 * Purpose:
 *   Return information for the specified interface 'ifname'.
 *
 *   This API directly returns the ifstate for the specified interface.
 *   This is the only way to access information about an interface that isn't
 *   available for general networking.
 *
 *   Returns NULL if no information is available for that interface.
 */
nwi_ifstate_t
nwi_state_get_ifstate(nwi_state_t state, const char * ifname)
{
        nwi_ifstate_t ifstate = nwi_state_get_ifstate_with_name(state, AF_INET, ifname);
        if (ifstate == NULL) {
                ifstate = nwi_state_get_ifstate_with_name(state, AF_INET6, ifname);
        }
        return ifstate;

}

/*
 * Function: nwi_ifstate_get_next
 * Purpose:
 *   Returns the next, lower priority nwi_ifstate_t after the specified
 *   'ifstate' for the protocol family 'af'.
 *
 *   Returns NULL when the end of the list is reached, or we reach an
 *   item that is not in the list.
 */
nwi_ifstate_t
nwi_ifstate_get_next(nwi_ifstate_t ifstate, int af)
{
        ifstate = nwi_ifstate_get_alias(ifstate, af);
        if (ifstate == NULL
            || ((ifstate->flags
                 & (NWI_IFSTATE_FLAGS_NOT_IN_LIST
                    | NWI_IFSTATE_FLAGS_LAST_ITEM))
                != 0)) {
                return (NULL);
        }
        ifstate++;
        if ((ifstate->flags & NWI_IFSTATE_FLAGS_NOT_IN_LIST) != 0) {
                return (NULL);
        }
        return (ifstate);
}

/*
 * Function: nwi_ifstate_compare_rank
 * Purpose:
 *   Compare the relative rank of two nwi_ifstate_t objects.
 *
 *   The "rank" indicates the importance of the underlying interface.
 *
 * Returns:
 *   0  if ifstate1 and ifstate2 are ranked equally
 *  -1  if ifstate1 is ranked ahead of ifstate2
 *   1  if ifstate2 is ranked ahead of ifstate1
 */
int
nwi_ifstate_compare_rank(nwi_ifstate_t ifstate1, nwi_ifstate_t ifstate2)
{
        return RankCompare(ifstate1->rank, ifstate2->rank);
}

/*
 * nwi_state_get_reachability_flags
 *
 * returns the global reachability flags for a given address family.
 * If no address family is passed in, it returns the global reachability
 * flags for either families.
 *
 * The reachability flags returned follow the definition of
 * SCNetworkReachabilityFlags.
 *
 * If the flags are zero (i.e. do not contain kSCNetworkReachabilityFlagsReachable), there is no connectivity.
 *
 * Otherwise, at least kSCNetworkReachabilityFlagsReachable is set:
 *        Reachable only
 *          No other connection flags are set.
 *        Reachable and no ConnectionRequired
 *          If we have connectivity for the specified address family (and we'd
 *          be returning the reachability flags associated with the default route)
 *        Reachable and ConnectionRequired
 *          If we do not currently have an active/primary network but we may
 *          be able to establish connectivity.
 *        Reachable and OnDemand
 *          If we do not currently have an active/primary network but we may
 *          be able to establish connective on demand.
 *        Reachable and TransientConnection
 *          This connection is transient.
 *        Reachable and WWAN
 *          This connection will be going over the cellular network.
 */
uint32_t
nwi_state_get_reachability_flags(nwi_state_t nwi_state, int af)
{
        if (nwi_state == NULL) {
                return (0);
        }
        if (af == AF_INET || af == AF_INET6) {
                nwi_ifstate_t ifstate;

                ifstate = nwi_state_get_first_ifstate(nwi_state, af);

                if (ifstate != NULL) {
                        return ifstate->reach_flags;
                }

                return (af == AF_INET) ? nwi_state->reach_flags_v4 : nwi_state->reach_flags_v6;
        } else {
                nwi_ifstate_t ifstate_v4;
                nwi_ifstate_t ifstate_v6;

                ifstate_v4 = nwi_state_get_first_ifstate(nwi_state, AF_INET);
                ifstate_v6 = nwi_state_get_first_ifstate(nwi_state, AF_INET6);

                if (ifstate_v4 != NULL) {
                        if (ifstate_v6 != NULL) {
                                if (nwi_ifstate_compare_rank(ifstate_v4, ifstate_v6) > 0) {
                                        return ifstate_v6->reach_flags;
                                } else {
                                        return ifstate_v4->reach_flags;
                                }
                        } else {
                                return ifstate_v4->reach_flags;
                        }
                } else {
                        if (ifstate_v6 != NULL) {
                                return ifstate_v6->reach_flags;
                        }
                }

                if (nwi_state->reach_flags_v4 != 0) {
                        return nwi_state->reach_flags_v4;
                }
                // This is the case where both ifstate are NULL.
                return nwi_state->reach_flags_v6;
        }
}

/*
 * nwi_ifstate_get_vpn_server
 *
 * returns a sockaddr representation of the vpn server address.
 * NULL if PPP/VPN/IPSec server address does not exist.
 */
const struct sockaddr *
nwi_ifstate_get_vpn_server(nwi_ifstate_t ifstate)
{
        const struct sockaddr * vpn_server_addr;

        vpn_server_addr = (const struct sockaddr *)(void *)
                           &ifstate->vpn_server_address;

        if (vpn_server_addr->sa_family == 0) {
                return NULL;
        }
        return vpn_server_addr;
}

/*
 * nwi_ifstate_get_reachability_flags
 *
 * returns the reachability flags for the interface given an address family.
 * The flags returned are those determined outside of
 * the routing table.  [None, ConnectionRequired, OnDemand,
 * Transient Connection, WWAN].
 */
uint32_t
nwi_ifstate_get_reachability_flags(nwi_ifstate_t ifstate)
{
        return ifstate->reach_flags;
}

/*
 * nwi_ifstate_get_signature
 *
 * returns the signature and its length for an ifstate given an address family.
 * If AF_UNSPEC is passed in, the signature for a given ifstate is returned.
 *
 * If the signature does not exist, NULL is returned.
 */
const uint8_t *
nwi_ifstate_get_signature(nwi_ifstate_t ifstate, int af, int * length)
{
        nwi_ifstate_t i_state = NULL;

        switch (af) {
                case AF_UNSPEC:
                        i_state = ifstate;
                        break;
                case AF_INET:
                case AF_INET6:
                        i_state = nwi_ifstate_get_alias(ifstate, af);
                        break;
                default:
                        break;

        }

        if (i_state != NULL) {
                if ((i_state->flags & NWI_IFSTATE_FLAGS_HAS_SIGNATURE) != 0) {
                        *length = sizeof(i_state->signature);
                        return (i_state->signature);
                }
        }

        *length = 0;
        return NULL;
}

static inline
boolean_t
_nwi_ifstate_is_in_list(nwi_ifstate_t ifstate, int af)
{
        nwi_ifstate_t i_state;

        i_state = nwi_ifstate_get_alias(ifstate, af);
        if (i_state == NULL) {
                return FALSE;
        }

        if ((nwi_ifstate_get_flags(i_state) & NWI_IFSTATE_FLAGS_NOT_IN_LIST)
            == 0) {
                return TRUE;
        }

        return FALSE;
}

/*
 * nwi_ifstate_get_dns_signature
 *
 * returns the signature and its length for given
 * ifstate with a valid dns configuration.
 *
 * If the signature does not exist, NULL is returned.
 *
 */
const uint8_t *
nwi_ifstate_get_dns_signature(nwi_ifstate_t ifstate, int * length)
{
        const uint8_t * signature = NULL;
        const uint8_t * v4_signature;
        int             v4_signature_len;
        const uint8_t * v6_signature;
        int             v6_signature_len;

        *length = 0;

        if ((nwi_ifstate_get_flags(ifstate) & NWI_IFSTATE_FLAGS_HAS_DNS) == 0) {
                return NULL;
        }

        v4_signature = nwi_ifstate_get_signature(ifstate, AF_INET, &v4_signature_len);
        v6_signature = nwi_ifstate_get_signature(ifstate, AF_INET6, &v6_signature_len);
        if (v4_signature == NULL && v6_signature == NULL) {
                return NULL;
        }

        if (_nwi_ifstate_is_in_list(ifstate, AF_INET)) {
                signature = v4_signature;
                *length = v4_signature_len;
        } else {
                if (_nwi_ifstate_is_in_list(ifstate, AF_INET6) != TRUE && v4_signature_len > 0) {
                        /* v6 is ranked never, v4 is ranked never but has a valid signature */
                        signature = v4_signature;
                        *length = v4_signature_len;
                } else {
                        /* v6 is not ranked never or v4 has no signature */
                        signature = v6_signature;
                        *length = v6_signature_len;
                }
        }

        return signature;
}

unsigned int
nwi_state_get_interface_names(nwi_state_t state,
                              const char * names[],
                              unsigned int names_count)
{
        int             i;
        nwi_ifindex_t * scan;

        if (names == NULL || names_count == 0) {
                return (state->if_list_count);
        }
        for (i = 0, scan = nwi_state_if_list(state);
             i < state->if_list_count; i++, scan++) {
                names[i] = state->ifstate_list[*scan].ifname;
        }
        return (state->if_list_count);
}

#pragma mark -
#pragma mark Network information [nwi] test code


#ifdef TEST_NWI

#include <arpa/inet.h>

typedef union {
        const struct sockaddr *         sa;
        const struct sockaddr_in *      sin;
        const struct sockaddr_in6 *     sin6;
} my_sockaddr_t;

static const char *
my_sockaddr_ntop(const struct sockaddr * sa, char * buf, int buf_len)
{
        my_sockaddr_t   addr;
        const void *    addr_ptr = NULL;

        addr.sa = sa;
        switch (sa->sa_family) {
        case AF_INET:
                addr_ptr = &addr.sin->sin_addr;
                break;
        case AF_INET6:
                addr_ptr = &addr.sin6->sin6_addr;
                break;
        default:
                addr_ptr = NULL;
                break;
        }
        if (addr_ptr == NULL) {
                return (NULL);
        }
        return (inet_ntop(addr.sa->sa_family, addr_ptr, buf, buf_len));
}

static void
nwi_ifstate_print(nwi_ifstate_t ifstate)
{
        const char *            addr_str;
        void *                  address;
        char                    addr_ntopbuf[INET6_ADDRSTRLEN];
        const char *            diff_str;
        char                    vpn_ntopbuf[INET6_ADDRSTRLEN];
        const struct sockaddr * vpn_addr;
        const char *            vpn_addr_str = NULL;

        address = nwi_ifstate_get_address(ifstate);
        addr_str = inet_ntop(ifstate->af, address,
                             addr_ntopbuf, sizeof(addr_ntopbuf));
        vpn_addr = nwi_ifstate_get_vpn_server(ifstate);
        if (vpn_addr != NULL) {
                vpn_addr_str = my_sockaddr_ntop(vpn_addr, vpn_ntopbuf,
                                                sizeof(vpn_ntopbuf));
        }
        diff_str = nwi_ifstate_get_diff_str(ifstate);
        printf("%s%s%s%s%s rank 0x%x iaddr %s%s%s reach_flags 0x%x\n",
               ifstate->ifname,
               diff_str,
               (ifstate->flags & NWI_IFSTATE_FLAGS_HAS_DNS) != 0
                        ? " dns" : "",
               (ifstate->flags & NWI_IFSTATE_FLAGS_HAS_CLAT46) != 0
                        ? " clat46" : "",
               (ifstate->flags & NWI_IFSTATE_FLAGS_NOT_IN_LIST) != 0
                        ? " never" : "",
               ifstate->rank,
               addr_str,
               (vpn_addr_str != NULL) ? " vpn_server_addr: " : "",
               (vpn_addr_str != NULL) ? vpn_addr_str : "",
               ifstate->reach_flags);
        return;
}

static void
traverse_ifstates(nwi_state_t state)
{
        nwi_ifstate_t   alias;
        int             i;
        nwi_ifstate_t   scan;

        scan = nwi_state_get_first_ifstate(state, AF_INET);
        printf("IPv4 traverse list:\n");
        for (i = 0; scan != NULL; i++) {
                printf("[%d] flags=0x%llx ", i, scan->flags);
                nwi_ifstate_print(scan);
                alias = nwi_ifstate_get_alias(scan, nwi_other_af(scan->af));
                scan = nwi_ifstate_get_next(scan, AF_INET);
                if (alias != NULL) {
                        printf("\t alias is ");
                        nwi_ifstate_print(alias);
                }
        }
        printf("IPv6 traverse list:\n");
        scan = nwi_state_get_first_ifstate(state, AF_INET6);
        for (i = 0; scan != NULL; i++) {
                printf("[%d] flags=0x%llx ", i, scan->flags);
                alias = nwi_ifstate_get_alias(scan, nwi_other_af(scan->af));
                nwi_ifstate_print(scan);
                scan = nwi_ifstate_get_next(scan, AF_INET6);
                if (alias != NULL) {
                        printf("\t alias is ");
                        nwi_ifstate_print(alias);
                }
        }
}

static void
nwi_state_print_common(nwi_state_t state, bool diff)
{
        unsigned int    count = 0;
        int             i;
        nwi_ifstate_t   scan;

        if (state == NULL) {
                return;
        }
        printf("nwi_state = { "
               "gen=%llu max_if=%u #v4=%u #v6=%u "
               "reach_flags=(v4=0x%x, v6=0x%x) }\n",
               state->generation_count,
               state->max_if_count,
               state->ipv4_count,
               state->ipv6_count,
               nwi_state_get_reachability_flags(state, AF_INET),
               nwi_state_get_reachability_flags(state, AF_INET6));
        if (state->ipv4_count) {
                printf("IPv4:\n");
                for (i = 0, scan = nwi_state_ifstate_list(state, AF_INET);
                     i < state->ipv4_count; i++, scan++) {
                        printf("[%d] ", i);
                        nwi_ifstate_print(scan);
                }
        }
        if (state->ipv6_count) {
                printf("IPv6:\n");
                for (i = 0, scan = nwi_state_ifstate_list(state, AF_INET6);
                     i < state->ipv6_count; i++, scan++) {
                        printf("[%d] ", i);
                        nwi_ifstate_print(scan);
                }
        }
        if (!diff) {
                count = nwi_state_get_interface_names(state, NULL, 0);
                if (count > 0) {
                        const char *    names[count];

                        count = nwi_state_get_interface_names(state, names,
                                                              count);
                        printf("%d interfaces%s", count,
                               (count != 0) ? ": " : "");
                        for (i = 0; i < count; i++) {
                                printf("%s%s", (i == 0) ? "" : ", ", names[i]);
                        }
                        printf("\n");
                }
                else {
                        printf("0 interfaces\n");
                }
                traverse_ifstates(state);
        }
        printf("-----------------------------------\n");
        return;
}

static void
nwi_state_print(nwi_state_t state)
{
        nwi_state_print_common(state, FALSE);
}

static void
nwi_state_print_diff(nwi_state_t state)
{
        printf("DIFF\n");
        nwi_state_print_common(state, TRUE);
}

static void
doit(void)
{
        struct in_addr  addr = { 0 };
        struct in6_addr addr6;
        nwi_ifstate_t   ifstate;
        nwi_state_t     state;
        nwi_state_t     diff_state;
        nwi_state_t     new_state;
        nwi_state_t     old_state;
        nwi_state_t     old_state_copy;

        state = nwi_state_new(NULL, 0);
        nwi_state_print(state);
        state = nwi_state_new(NULL, 1);
        nwi_state_print(state);
        state = nwi_state_new(state, 2);
        nwi_state_print(state);
        state = nwi_state_new(state, 10);
        nwi_state_print(state);

        bzero(&addr6, sizeof(addr6));
        /* populate old_state */
        old_state = nwi_state_new(NULL, 5);
        for (int i = 0; i < 5; i++) {
                char            ifname[IFNAMSIZ];

                snprintf(ifname, sizeof(ifname), "en%d", i);
                addr.s_addr = htonl((i % 2) ? i : (i + 1));
                ifstate = nwi_state_add_ifstate(old_state, ifname, AF_INET, 0,
                                                (i % 2) ? (i - 1) : (i + 1),
                                                &addr,
                                                NULL,
                                                0);
                addr6.__u6_addr.__u6_addr32[0] = htonl(i);
                ifstate = nwi_state_add_ifstate(old_state, ifname, AF_INET6, 0,
                                                (i % 2) ? (10 - i) : i,
                                                &addr6,
                                                NULL,
                                                0);
        }
        nwi_state_finalize(old_state);
        nwi_state_print(old_state);

        diff_state = nwi_state_diff(NULL, old_state);
        nwi_state_print_diff(diff_state);
        nwi_state_free(diff_state);

        /* remember the old state */
        old_state_copy = nwi_state_make_copy(old_state);

        /* create new state */
        new_state = nwi_state_new(old_state, 10);
        nwi_state_print(new_state);

        for (int i = 0; i < 10; i++) {
                char            ifname[IFNAMSIZ];
                uint64_t        flags;

                snprintf(ifname, sizeof(ifname), "en%d", i);
                addr6.__u6_addr.__u6_addr32[0] = htonl(i);
                flags = (i > 6) ? NWI_IFSTATE_FLAGS_NOT_IN_LIST : 0;
                ifstate = nwi_state_add_ifstate(new_state, ifname, AF_INET6,
                                                flags,
                                                i,
                                                &addr6,
                                                NULL,
                                                0);
        }
        for (int i = 9; i >= 0; i--) {
                char            ifname[IFNAMSIZ];

                snprintf(ifname, sizeof(ifname), "en%d", i);
                addr.s_addr = htonl(i);
                if (i != 3) {
                        ifstate = nwi_state_add_ifstate(new_state,
                                                        ifname, AF_INET,
                                                        0,
                                                        i,
                                                        &addr,
                                                        NULL,
                                                        0);
                }
        }
        nwi_state_finalize(new_state);
        nwi_state_print(new_state);

        diff_state = nwi_state_diff(old_state_copy, new_state);
        nwi_state_print_diff(diff_state);
        nwi_state_free(diff_state);

        diff_state = nwi_state_diff(new_state, old_state_copy);
        nwi_state_print_diff(diff_state);
        nwi_state_free(diff_state);

        nwi_state_free(old_state_copy);
        nwi_state_free(new_state);
        return;
}

int
main()
{
        doit();
        exit(0);
        return (0);
}

#endif /* TEST_NWI */

#ifdef TEST_NWI_STATE

int
main(int argc, char * argv[])
{
        nwi_state_t state = nwi_state_copy();

        exit(0);
        return (0);
}

#endif