Added WirelessManager, a port of wpa_supplicant.

[AROS.git] / workbench / network / WirelessManager / src / radius / radius_client.c

/*
 * RADIUS client
 * Copyright (c) 2002-2009, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "radius.h"
#include "radius_client.h"
#include "eloop.h"

/* Defaults for RADIUS retransmit values (exponential backoff) */

/**
 * RADIUS_CLIENT_FIRST_WAIT - RADIUS client timeout for first retry in seconds
 */
#define RADIUS_CLIENT_FIRST_WAIT 3

/**
 * RADIUS_CLIENT_MAX_WAIT - RADIUS client maximum retry timeout in seconds
 */
#define RADIUS_CLIENT_MAX_WAIT 120

/**
 * RADIUS_CLIENT_MAX_RETRIES - RADIUS client maximum retries
 *
 * Maximum number of retransmit attempts before the entry is removed from
 * retransmit list.
 */
#define RADIUS_CLIENT_MAX_RETRIES 10

/**
 * RADIUS_CLIENT_MAX_ENTRIES - RADIUS client maximum pending messages
 *
 * Maximum number of entries in retransmit list (oldest entries will be
 * removed, if this limit is exceeded).
 */
#define RADIUS_CLIENT_MAX_ENTRIES 30

/**
 * RADIUS_CLIENT_NUM_FAILOVER - RADIUS client failover point
 *
 * The number of failed retry attempts after which the RADIUS server will be
 * changed (if one of more backup servers are configured).
 */
#define RADIUS_CLIENT_NUM_FAILOVER 4


/**
 * struct radius_rx_handler - RADIUS client RX handler
 *
 * This data structure is used internally inside the RADIUS client module to
 * store registered RX handlers. These handlers are registered by calls to
 * radius_client_register() and unregistered when the RADIUS client is
 * deinitialized with a call to radius_client_deinit().
 */
struct radius_rx_handler {
        /**
         * handler - Received RADIUS message handler
         */
        RadiusRxResult (*handler)(struct radius_msg *msg,
                                  struct radius_msg *req,
                                  const u8 *shared_secret,
                                  size_t shared_secret_len,
                                  void *data);

        /**
         * data - Context data for the handler
         */
        void *data;
};


/**
 * struct radius_msg_list - RADIUS client message retransmit list
 *
 * This data structure is used internally inside the RADIUS client module to
 * store pending RADIUS requests that may still need to be retransmitted.
 */
struct radius_msg_list {
        /**
         * addr - STA/client address
         *
         * This is used to find RADIUS messages for the same STA.
         */
        u8 addr[ETH_ALEN];

        /**
         * msg - RADIUS message
         */
        struct radius_msg *msg;

        /**
         * msg_type - Message type
         */
        RadiusType msg_type;

        /**
         * first_try - Time of the first transmission attempt
         */
        os_time_t first_try;

        /**
         * next_try - Time for the next transmission attempt
         */
        os_time_t next_try;

        /**
         * attempts - Number of transmission attempts
         */
        int attempts;

        /**
         * next_wait - Next retransmission wait time in seconds
         */
        int next_wait;

        /**
         * last_attempt - Time of the last transmission attempt
         */
        struct os_time last_attempt;

        /**
         * shared_secret - Shared secret with the target RADIUS server
         */
        const u8 *shared_secret;

        /**
         * shared_secret_len - shared_secret length in octets
         */
        size_t shared_secret_len;

        /* TODO: server config with failover to backup server(s) */

        /**
         * next - Next message in the list
         */
        struct radius_msg_list *next;
};


/**
 * struct radius_client_data - Internal RADIUS client data
 *
 * This data structure is used internally inside the RADIUS client module.
 * External users allocate this by calling radius_client_init() and free it by
 * calling radius_client_deinit(). The pointer to this opaque data is used in
 * calls to other functions as an identifier for the RADIUS client instance.
 */
struct radius_client_data {
        /**
         * ctx - Context pointer for hostapd_logger() callbacks
         */
        void *ctx;

        /**
         * conf - RADIUS client configuration (list of RADIUS servers to use)
         */
        struct hostapd_radius_servers *conf;

        /**
         * auth_serv_sock - IPv4 socket for RADIUS authentication messages
         */
        int auth_serv_sock;

        /**
         * acct_serv_sock - IPv4 socket for RADIUS accounting messages
         */
        int acct_serv_sock;

        /**
         * auth_serv_sock6 - IPv6 socket for RADIUS authentication messages
         */
        int auth_serv_sock6;

        /**
         * acct_serv_sock6 - IPv6 socket for RADIUS accounting messages
         */
        int acct_serv_sock6;

        /**
         * auth_sock - Currently used socket for RADIUS authentication server
         */
        int auth_sock;

        /**
         * acct_sock - Currently used socket for RADIUS accounting server
         */
        int acct_sock;

        /**
         * auth_handlers - Authentication message handlers
         */
        struct radius_rx_handler *auth_handlers;

        /**
         * num_auth_handlers - Number of handlers in auth_handlers
         */
        size_t num_auth_handlers;

        /**
         * acct_handlers - Accounting message handlers
         */
        struct radius_rx_handler *acct_handlers;

        /**
         * num_acct_handlers - Number of handlers in acct_handlers
         */
        size_t num_acct_handlers;

        /**
         * msgs - Pending outgoing RADIUS messages
         */
        struct radius_msg_list *msgs;

        /**
         * num_msgs - Number of pending messages in the msgs list
         */
        size_t num_msgs;

        /**
         * next_radius_identifier - Next RADIUS message identifier to use
         */
        u8 next_radius_identifier;
};


static int
radius_change_server(struct radius_client_data *radius,
                     struct hostapd_radius_server *nserv,
                     struct hostapd_radius_server *oserv,
                     int sock, int sock6, int auth);
static int radius_client_init_acct(struct radius_client_data *radius);
static int radius_client_init_auth(struct radius_client_data *radius);


static void radius_client_msg_free(struct radius_msg_list *req)
{
        radius_msg_free(req->msg);
        os_free(req);
}


/**
 * radius_client_register - Register a RADIUS client RX handler
 * @radius: RADIUS client context from radius_client_init()
 * @msg_type: RADIUS client type (RADIUS_AUTH or RADIUS_ACCT)
 * @handler: Handler for received RADIUS messages
 * @data: Context pointer for handler callbacks
 * Returns: 0 on success, -1 on failure
 *
 * This function is used to register a handler for processing received RADIUS
 * authentication and accounting messages. The handler() callback function will
 * be called whenever a RADIUS message is received from the active server.
 *
 * There can be multiple registered RADIUS message handlers. The handlers will
 * be called in order until one of them indicates that it has processed or
 * queued the message.
 */
int radius_client_register(struct radius_client_data *radius,
                           RadiusType msg_type,
                           RadiusRxResult (*handler)(struct radius_msg *msg,
                                                     struct radius_msg *req,
                                                     const u8 *shared_secret,
                                                     size_t shared_secret_len,
                                                     void *data),
                           void *data)
{
        struct radius_rx_handler **handlers, *newh;
        size_t *num;

        if (msg_type == RADIUS_ACCT) {
                handlers = &radius->acct_handlers;
                num = &radius->num_acct_handlers;
        } else {
                handlers = &radius->auth_handlers;
                num = &radius->num_auth_handlers;
        }

        newh = os_realloc(*handlers,
                          (*num + 1) * sizeof(struct radius_rx_handler));
        if (newh == NULL)
                return -1;

        newh[*num].handler = handler;
        newh[*num].data = data;
        (*num)++;
        *handlers = newh;

        return 0;
}


static void radius_client_handle_send_error(struct radius_client_data *radius,
                                            int s, RadiusType msg_type)
{
#ifndef CONFIG_NATIVE_WINDOWS
        int _errno = errno;
        perror("send[RADIUS]");
        if (_errno == ENOTCONN || _errno == EDESTADDRREQ || _errno == EINVAL ||
            _errno == EBADF) {
                hostapd_logger(radius->ctx, NULL, HOSTAPD_MODULE_RADIUS,
                               HOSTAPD_LEVEL_INFO,
                               "Send failed - maybe interface status changed -"
                               " try to connect again");
                eloop_unregister_read_sock(s);
                close(s);
                if (msg_type == RADIUS_ACCT || msg_type == RADIUS_ACCT_INTERIM)
                        radius_client_init_acct(radius);
                else
                        radius_client_init_auth(radius);
        }
#endif /* CONFIG_NATIVE_WINDOWS */
}


static int radius_client_retransmit(struct radius_client_data *radius,
                                    struct radius_msg_list *entry,
                                    os_time_t now)
{
        struct hostapd_radius_servers *conf = radius->conf;
        int s;
        struct wpabuf *buf;

        if (entry->msg_type == RADIUS_ACCT ||
            entry->msg_type == RADIUS_ACCT_INTERIM) {
                s = radius->acct_sock;
                if (entry->attempts == 0)
                        conf->acct_server->requests++;
                else {
                        conf->acct_server->timeouts++;
                        conf->acct_server->retransmissions++;
                }
        } else {
                s = radius->auth_sock;
                if (entry->attempts == 0)
                        conf->auth_server->requests++;
                else {
                        conf->auth_server->timeouts++;
                        conf->auth_server->retransmissions++;
                }
        }

        /* retransmit; remove entry if too many attempts */
        entry->attempts++;
        hostapd_logger(radius->ctx, entry->addr, HOSTAPD_MODULE_RADIUS,
                       HOSTAPD_LEVEL_DEBUG, "Resending RADIUS message (id=%d)",
                       radius_msg_get_hdr(entry->msg)->identifier);

        os_get_time(&entry->last_attempt);
        buf = radius_msg_get_buf(entry->msg);
        if (send(s, wpabuf_head(buf), wpabuf_len(buf), 0) < 0)
                radius_client_handle_send_error(radius, s, entry->msg_type);

        entry->next_try = now + entry->next_wait;
        entry->next_wait *= 2;
        if (entry->next_wait > RADIUS_CLIENT_MAX_WAIT)
                entry->next_wait = RADIUS_CLIENT_MAX_WAIT;
        if (entry->attempts >= RADIUS_CLIENT_MAX_RETRIES) {
                printf("Removing un-ACKed RADIUS message due to too many "
                       "failed retransmit attempts\n");
                return 1;
        }

        return 0;
}


static void radius_client_timer(void *eloop_ctx, void *timeout_ctx)
{
        struct radius_client_data *radius = eloop_ctx;
        struct hostapd_radius_servers *conf = radius->conf;
        struct os_time now;
        os_time_t first;
        struct radius_msg_list *entry, *prev, *tmp;
        int auth_failover = 0, acct_failover = 0;
        char abuf[50];

        entry = radius->msgs;
        if (!entry)
                return;

        os_get_time(&now);
        first = 0;

        prev = NULL;
        while (entry) {
                if (now.sec >= entry->next_try &&
                    radius_client_retransmit(radius, entry, now.sec)) {
                        if (prev)
                                prev->next = entry->next;
                        else
                                radius->msgs = entry->next;

                        tmp = entry;
                        entry = entry->next;
                        radius_client_msg_free(tmp);
                        radius->num_msgs--;
                        continue;
                }

                if (entry->attempts > RADIUS_CLIENT_NUM_FAILOVER) {
                        if (entry->msg_type == RADIUS_ACCT ||
                            entry->msg_type == RADIUS_ACCT_INTERIM)
                                acct_failover++;
                        else
                                auth_failover++;
                }

                if (first == 0 || entry->next_try < first)
                        first = entry->next_try;

                prev = entry;
                entry = entry->next;
        }

        if (radius->msgs) {
                if (first < now.sec)
                        first = now.sec;
                eloop_register_timeout(first - now.sec, 0,
                                       radius_client_timer, radius, NULL);
                hostapd_logger(radius->ctx, NULL, HOSTAPD_MODULE_RADIUS,
                               HOSTAPD_LEVEL_DEBUG, "Next RADIUS client "
                               "retransmit in %ld seconds",
                               (long int) (first - now.sec));
        }

        if (auth_failover && conf->num_auth_servers > 1) {
                struct hostapd_radius_server *next, *old;
                old = conf->auth_server;
                hostapd_logger(radius->ctx, NULL, HOSTAPD_MODULE_RADIUS,
                               HOSTAPD_LEVEL_NOTICE,
                               "No response from Authentication server "
                               "%s:%d - failover",
                               hostapd_ip_txt(&old->addr, abuf, sizeof(abuf)),
                               old->port);

                for (entry = radius->msgs; entry; entry = entry->next) {
                        if (entry->msg_type == RADIUS_AUTH)
                                old->timeouts++;
                }

                next = old + 1;
                if (next > &(conf->auth_servers[conf->num_auth_servers - 1]))
                        next = conf->auth_servers;
                conf->auth_server = next;
                radius_change_server(radius, next, old,
                                     radius->auth_serv_sock,
                                     radius->auth_serv_sock6, 1);
        }

        if (acct_failover && conf->num_acct_servers > 1) {
                struct hostapd_radius_server *next, *old;
                old = conf->acct_server;
                hostapd_logger(radius->ctx, NULL, HOSTAPD_MODULE_RADIUS,
                               HOSTAPD_LEVEL_NOTICE,
                               "No response from Accounting server "
                               "%s:%d - failover",
                               hostapd_ip_txt(&old->addr, abuf, sizeof(abuf)),
                               old->port);

                for (entry = radius->msgs; entry; entry = entry->next) {
                        if (entry->msg_type == RADIUS_ACCT ||
                            entry->msg_type == RADIUS_ACCT_INTERIM)
                                old->timeouts++;
                }

                next = old + 1;
                if (next > &conf->acct_servers[conf->num_acct_servers - 1])
                        next = conf->acct_servers;
                conf->acct_server = next;
                radius_change_server(radius, next, old,
                                     radius->acct_serv_sock,
                                     radius->acct_serv_sock6, 0);
        }
}


static void radius_client_update_timeout(struct radius_client_data *radius)
{
        struct os_time now;
        os_time_t first;
        struct radius_msg_list *entry;

        eloop_cancel_timeout(radius_client_timer, radius, NULL);

        if (radius->msgs == NULL) {
                return;
        }

        first = 0;
        for (entry = radius->msgs; entry; entry = entry->next) {
                if (first == 0 || entry->next_try < first)
                        first = entry->next_try;
        }

        os_get_time(&now);
        if (first < now.sec)
                first = now.sec;
        eloop_register_timeout(first - now.sec, 0, radius_client_timer, radius,
                               NULL);
        hostapd_logger(radius->ctx, NULL, HOSTAPD_MODULE_RADIUS,
                       HOSTAPD_LEVEL_DEBUG, "Next RADIUS client retransmit in"
                       " %ld seconds\n", (long int) (first - now.sec));
}


static void radius_client_list_add(struct radius_client_data *radius,
                                   struct radius_msg *msg,
                                   RadiusType msg_type,
                                   const u8 *shared_secret,
                                   size_t shared_secret_len, const u8 *addr)
{
        struct radius_msg_list *entry, *prev;

        if (eloop_terminated()) {
                /* No point in adding entries to retransmit queue since event
                 * loop has already been terminated. */
                radius_msg_free(msg);
                return;
        }

        entry = os_zalloc(sizeof(*entry));
        if (entry == NULL) {
                printf("Failed to add RADIUS packet into retransmit list\n");
                radius_msg_free(msg);
                return;
        }

        if (addr)
                os_memcpy(entry->addr, addr, ETH_ALEN);
        entry->msg = msg;
        entry->msg_type = msg_type;
        entry->shared_secret = shared_secret;
        entry->shared_secret_len = shared_secret_len;
        os_get_time(&entry->last_attempt);
        entry->first_try = entry->last_attempt.sec;
        entry->next_try = entry->first_try + RADIUS_CLIENT_FIRST_WAIT;
        entry->attempts = 1;
        entry->next_wait = RADIUS_CLIENT_FIRST_WAIT * 2;
        entry->next = radius->msgs;
        radius->msgs = entry;
        radius_client_update_timeout(radius);

        if (radius->num_msgs >= RADIUS_CLIENT_MAX_ENTRIES) {
                printf("Removing the oldest un-ACKed RADIUS packet due to "
                       "retransmit list limits.\n");
                prev = NULL;
                while (entry->next) {
                        prev = entry;
                        entry = entry->next;
                }
                if (prev) {
                        prev->next = NULL;
                        radius_client_msg_free(entry);
                }
        } else
                radius->num_msgs++;
}


static void radius_client_list_del(struct radius_client_data *radius,
                                   RadiusType msg_type, const u8 *addr)
{
        struct radius_msg_list *entry, *prev, *tmp;

        if (addr == NULL)
                return;

        entry = radius->msgs;
        prev = NULL;
        while (entry) {
                if (entry->msg_type == msg_type &&
                    os_memcmp(entry->addr, addr, ETH_ALEN) == 0) {
                        if (prev)
                                prev->next = entry->next;
                        else
                                radius->msgs = entry->next;
                        tmp = entry;
                        entry = entry->next;
                        hostapd_logger(radius->ctx, addr,
                                       HOSTAPD_MODULE_RADIUS,
                                       HOSTAPD_LEVEL_DEBUG,
                                       "Removing matching RADIUS message");
                        radius_client_msg_free(tmp);
                        radius->num_msgs--;
                        continue;
                }
                prev = entry;
                entry = entry->next;
        }
}


/**
 * radius_client_send - Send a RADIUS request
 * @radius: RADIUS client context from radius_client_init()
 * @msg: RADIUS message to be sent
 * @msg_type: Message type (RADIUS_AUTH, RADIUS_ACCT, RADIUS_ACCT_INTERIM)
 * @addr: MAC address of the device related to this message or %NULL
 * Returns: 0 on success, -1 on failure
 *
 * This function is used to transmit a RADIUS authentication (RADIUS_AUTH) or
 * accounting request (RADIUS_ACCT or RADIUS_ACCT_INTERIM). The only difference
 * between accounting and interim accounting messages is that the interim
 * message will override any pending interim accounting updates while a new
 * accounting message does not remove any pending messages.
 *
 * The message is added on the retransmission queue and will be retransmitted
 * automatically until a response is received or maximum number of retries
 * (RADIUS_CLIENT_MAX_RETRIES) is reached.
 *
 * The related device MAC address can be used to identify pending messages that
 * can be removed with radius_client_flush_auth() or with interim accounting
 * updates.
 */
int radius_client_send(struct radius_client_data *radius,
                       struct radius_msg *msg, RadiusType msg_type,
                       const u8 *addr)
{
        struct hostapd_radius_servers *conf = radius->conf;
        const u8 *shared_secret;
        size_t shared_secret_len;
        char *name;
        int s, res;
        struct wpabuf *buf;

        if (msg_type == RADIUS_ACCT_INTERIM) {
                /* Remove any pending interim acct update for the same STA. */
                radius_client_list_del(radius, msg_type, addr);
        }

        if (msg_type == RADIUS_ACCT || msg_type == RADIUS_ACCT_INTERIM) {
                if (conf->acct_server == NULL) {
                        hostapd_logger(radius->ctx, NULL,
                                       HOSTAPD_MODULE_RADIUS,
                                       HOSTAPD_LEVEL_INFO,
                                       "No accounting server configured");
                        return -1;
                }
                shared_secret = conf->acct_server->shared_secret;
                shared_secret_len = conf->acct_server->shared_secret_len;
                radius_msg_finish_acct(msg, shared_secret, shared_secret_len);
                name = "accounting";
                s = radius->acct_sock;
                conf->acct_server->requests++;
        } else {
                if (conf->auth_server == NULL) {
                        hostapd_logger(radius->ctx, NULL,
                                       HOSTAPD_MODULE_RADIUS,
                                       HOSTAPD_LEVEL_INFO,
                                       "No authentication server configured");
                        return -1;
                }
                shared_secret = conf->auth_server->shared_secret;
                shared_secret_len = conf->auth_server->shared_secret_len;
                radius_msg_finish(msg, shared_secret, shared_secret_len);
                name = "authentication";
                s = radius->auth_sock;
                conf->auth_server->requests++;
        }

        hostapd_logger(radius->ctx, NULL, HOSTAPD_MODULE_RADIUS,
                       HOSTAPD_LEVEL_DEBUG, "Sending RADIUS message to %s "
                       "server", name);
        if (conf->msg_dumps)
                radius_msg_dump(msg);

        buf = radius_msg_get_buf(msg);
        res = send(s, wpabuf_head(buf), wpabuf_len(buf), 0);
        if (res < 0)
                radius_client_handle_send_error(radius, s, msg_type);

        radius_client_list_add(radius, msg, msg_type, shared_secret,
                               shared_secret_len, addr);

        return res;
}


static void radius_client_receive(int sock, void *eloop_ctx, void *sock_ctx)
{
        struct radius_client_data *radius = eloop_ctx;
        struct hostapd_radius_servers *conf = radius->conf;
        RadiusType msg_type = (RadiusType) sock_ctx;
        int len, roundtrip;
        unsigned char buf[3000];
        struct radius_msg *msg;
        struct radius_hdr *hdr;
        struct radius_rx_handler *handlers;
        size_t num_handlers, i;
        struct radius_msg_list *req, *prev_req;
        struct os_time now;
        struct hostapd_radius_server *rconf;
        int invalid_authenticator = 0;

        if (msg_type == RADIUS_ACCT) {
                handlers = radius->acct_handlers;
                num_handlers = radius->num_acct_handlers;
                rconf = conf->acct_server;
        } else {
                handlers = radius->auth_handlers;
                num_handlers = radius->num_auth_handlers;
                rconf = conf->auth_server;
        }

        len = recv(sock, buf, sizeof(buf), MSG_DONTWAIT);
        if (len < 0) {
                perror("recv[RADIUS]");
                return;
        }
        hostapd_logger(radius->ctx, NULL, HOSTAPD_MODULE_RADIUS,
                       HOSTAPD_LEVEL_DEBUG, "Received %d bytes from RADIUS "
                       "server", len);
        if (len == sizeof(buf)) {
                printf("Possibly too long UDP frame for our buffer - "
                       "dropping it\n");
                return;
        }

        msg = radius_msg_parse(buf, len);
        if (msg == NULL) {
                printf("Parsing incoming RADIUS frame failed\n");
                rconf->malformed_responses++;
                return;
        }
        hdr = radius_msg_get_hdr(msg);

        hostapd_logger(radius->ctx, NULL, HOSTAPD_MODULE_RADIUS,
                       HOSTAPD_LEVEL_DEBUG, "Received RADIUS message");
        if (conf->msg_dumps)
                radius_msg_dump(msg);

        switch (hdr->code) {
        case RADIUS_CODE_ACCESS_ACCEPT:
                rconf->access_accepts++;
                break;
        case RADIUS_CODE_ACCESS_REJECT:
                rconf->access_rejects++;
                break;
        case RADIUS_CODE_ACCESS_CHALLENGE:
                rconf->access_challenges++;
                break;
        case RADIUS_CODE_ACCOUNTING_RESPONSE:
                rconf->responses++;
                break;
        }

        prev_req = NULL;
        req = radius->msgs;
        while (req) {
                /* TODO: also match by src addr:port of the packet when using
                 * alternative RADIUS servers (?) */
                if ((req->msg_type == msg_type ||
                     (req->msg_type == RADIUS_ACCT_INTERIM &&
                      msg_type == RADIUS_ACCT)) &&
                    radius_msg_get_hdr(req->msg)->identifier ==
                    hdr->identifier)
                        break;

                prev_req = req;
                req = req->next;
        }

        if (req == NULL) {
                hostapd_logger(radius->ctx, NULL, HOSTAPD_MODULE_RADIUS,
                               HOSTAPD_LEVEL_DEBUG,
                               "No matching RADIUS request found (type=%d "
                               "id=%d) - dropping packet",
                               msg_type, hdr->identifier);
                goto fail;
        }

        os_get_time(&now);
        roundtrip = (now.sec - req->last_attempt.sec) * 100 +
                (now.usec - req->last_attempt.usec) / 10000;
        hostapd_logger(radius->ctx, req->addr, HOSTAPD_MODULE_RADIUS,
                       HOSTAPD_LEVEL_DEBUG,
                       "Received RADIUS packet matched with a pending "
                       "request, round trip time %d.%02d sec",
                       roundtrip / 100, roundtrip % 100);
        rconf->round_trip_time = roundtrip;

        /* Remove ACKed RADIUS packet from retransmit list */
        if (prev_req)
                prev_req->next = req->next;
        else
                radius->msgs = req->next;
        radius->num_msgs--;

        for (i = 0; i < num_handlers; i++) {
                RadiusRxResult res;
                res = handlers[i].handler(msg, req->msg, req->shared_secret,
                                          req->shared_secret_len,
                                          handlers[i].data);
                switch (res) {
                case RADIUS_RX_PROCESSED:
                        radius_msg_free(msg);
                        /* continue */
                case RADIUS_RX_QUEUED:
                        radius_client_msg_free(req);
                        return;
                case RADIUS_RX_INVALID_AUTHENTICATOR:
                        invalid_authenticator++;
                        /* continue */
                case RADIUS_RX_UNKNOWN:
                        /* continue with next handler */
                        break;
                }
        }

        if (invalid_authenticator)
                rconf->bad_authenticators++;
        else
                rconf->unknown_types++;
        hostapd_logger(radius->ctx, req->addr, HOSTAPD_MODULE_RADIUS,
                       HOSTAPD_LEVEL_DEBUG, "No RADIUS RX handler found "
                       "(type=%d code=%d id=%d)%s - dropping packet",
                       msg_type, hdr->code, hdr->identifier,
                       invalid_authenticator ? " [INVALID AUTHENTICATOR]" :
                       "");
        radius_client_msg_free(req);

 fail:
        radius_msg_free(msg);
}


/**
 * radius_client_get_id - Get an identifier for a new RADIUS message
 * @radius: RADIUS client context from radius_client_init()
 * Returns: Allocated identifier
 *
 * This function is used to fetch a unique (among pending requests) identifier
 * for a new RADIUS message.
 */
u8 radius_client_get_id(struct radius_client_data *radius)
{
        struct radius_msg_list *entry, *prev, *_remove;
        u8 id = radius->next_radius_identifier++;

        /* remove entries with matching id from retransmit list to avoid
         * using new reply from the RADIUS server with an old request */
        entry = radius->msgs;
        prev = NULL;
        while (entry) {
                if (radius_msg_get_hdr(entry->msg)->identifier == id) {
                        hostapd_logger(radius->ctx, entry->addr,
                                       HOSTAPD_MODULE_RADIUS,
                                       HOSTAPD_LEVEL_DEBUG,
                                       "Removing pending RADIUS message, "
                                       "since its id (%d) is reused", id);
                        if (prev)
                                prev->next = entry->next;
                        else
                                radius->msgs = entry->next;
                        _remove = entry;
                } else {
                        _remove = NULL;
                        prev = entry;
                }
                entry = entry->next;

                if (_remove)
                        radius_client_msg_free(_remove);
        }

        return id;
}


/**
 * radius_client_flush - Flush all pending RADIUS client messages
 * @radius: RADIUS client context from radius_client_init()
 * @only_auth: Whether only authentication messages are removed
 */
void radius_client_flush(struct radius_client_data *radius, int only_auth)
{
        struct radius_msg_list *entry, *prev, *tmp;

        if (!radius)
                return;

        prev = NULL;
        entry = radius->msgs;

        while (entry) {
                if (!only_auth || entry->msg_type == RADIUS_AUTH) {
                        if (prev)
                                prev->next = entry->next;
                        else
                                radius->msgs = entry->next;

                        tmp = entry;
                        entry = entry->next;
                        radius_client_msg_free(tmp);
                        radius->num_msgs--;
                } else {
                        prev = entry;
                        entry = entry->next;
                }
        }

        if (radius->msgs == NULL)
                eloop_cancel_timeout(radius_client_timer, radius, NULL);
}


static void radius_client_update_acct_msgs(struct radius_client_data *radius,
                                           const u8 *shared_secret,
                                           size_t shared_secret_len)
{
        struct radius_msg_list *entry;

        if (!radius)
                return;

        for (entry = radius->msgs; entry; entry = entry->next) {
                if (entry->msg_type == RADIUS_ACCT) {
                        entry->shared_secret = shared_secret;
                        entry->shared_secret_len = shared_secret_len;
                        radius_msg_finish_acct(entry->msg, shared_secret,
                                               shared_secret_len);
                }
        }
}


static int
radius_change_server(struct radius_client_data *radius,
                     struct hostapd_radius_server *nserv,
                     struct hostapd_radius_server *oserv,
                     int sock, int sock6, int auth)
{
        struct sockaddr_in serv, claddr;
#ifdef CONFIG_IPV6
        struct sockaddr_in6 serv6, claddr6;
#endif /* CONFIG_IPV6 */
        struct sockaddr *addr, *cl_addr;
        socklen_t addrlen, claddrlen;
        char abuf[50];
        int sel_sock;
        struct radius_msg_list *entry;
        struct hostapd_radius_servers *conf = radius->conf;

        hostapd_logger(radius->ctx, NULL, HOSTAPD_MODULE_RADIUS,
                       HOSTAPD_LEVEL_INFO,
                       "%s server %s:%d",
                       auth ? "Authentication" : "Accounting",
                       hostapd_ip_txt(&nserv->addr, abuf, sizeof(abuf)),
                       nserv->port);

        if (!oserv || nserv->shared_secret_len != oserv->shared_secret_len ||
            os_memcmp(nserv->shared_secret, oserv->shared_secret,
                      nserv->shared_secret_len) != 0) {
                /* Pending RADIUS packets used different shared secret, so
                 * they need to be modified. Update accounting message
                 * authenticators here. Authentication messages are removed
                 * since they would require more changes and the new RADIUS
                 * server may not be prepared to receive them anyway due to
                 * missing state information. Client will likely retry
                 * authentication, so this should not be an issue. */
                if (auth)
                        radius_client_flush(radius, 1);
                else {
                        radius_client_update_acct_msgs(
                                radius, nserv->shared_secret,
                                nserv->shared_secret_len);
                }
        }

        /* Reset retry counters for the new server */
        for (entry = radius->msgs; entry; entry = entry->next) {
                if ((auth && entry->msg_type != RADIUS_AUTH) ||
                    (!auth && entry->msg_type != RADIUS_ACCT))
                        continue;
                entry->next_try = entry->first_try + RADIUS_CLIENT_FIRST_WAIT;
                entry->attempts = 0;
                entry->next_wait = RADIUS_CLIENT_FIRST_WAIT * 2;
        }

        if (radius->msgs) {
                eloop_cancel_timeout(radius_client_timer, radius, NULL);
                eloop_register_timeout(RADIUS_CLIENT_FIRST_WAIT, 0,
                                       radius_client_timer, radius, NULL);
        }

        switch (nserv->addr.af) {
        case AF_INET:
                os_memset(&serv, 0, sizeof(serv));
                serv.sin_family = AF_INET;
                serv.sin_addr.s_addr = nserv->addr.u.v4.s_addr;
                serv.sin_port = htons(nserv->port);
                addr = (struct sockaddr *) &serv;
                addrlen = sizeof(serv);
                sel_sock = sock;
                break;
#ifdef CONFIG_IPV6
        case AF_INET6:
                os_memset(&serv6, 0, sizeof(serv6));
                serv6.sin6_family = AF_INET6;
                os_memcpy(&serv6.sin6_addr, &nserv->addr.u.v6,
                          sizeof(struct in6_addr));
                serv6.sin6_port = htons(nserv->port);
                addr = (struct sockaddr *) &serv6;
                addrlen = sizeof(serv6);
                sel_sock = sock6;
                break;
#endif /* CONFIG_IPV6 */
        default:
                return -1;
        }

        if (conf->force_client_addr) {
                switch (conf->client_addr.af) {
                case AF_INET:
                        os_memset(&claddr, 0, sizeof(claddr));
                        claddr.sin_family = AF_INET;
                        claddr.sin_addr.s_addr = conf->client_addr.u.v4.s_addr;
                        claddr.sin_port = htons(0);
                        cl_addr = (struct sockaddr *) &claddr;
                        claddrlen = sizeof(claddr);
                        break;
#ifdef CONFIG_IPV6
                case AF_INET6:
                        os_memset(&claddr6, 0, sizeof(claddr6));
                        claddr6.sin6_family = AF_INET6;
                        os_memcpy(&claddr6.sin6_addr, &conf->client_addr.u.v6,
                                  sizeof(struct in6_addr));
                        claddr6.sin6_port = htons(0);
                        cl_addr = (struct sockaddr *) &claddr6;
                        claddrlen = sizeof(claddr6);
                        break;
#endif /* CONFIG_IPV6 */
                default:
                        return -1;
                }

                if (bind(sel_sock, cl_addr, claddrlen) < 0) {
                        perror("bind[radius]");
                        return -1;
                }
        }

        if (connect(sel_sock, addr, addrlen) < 0) {
                perror("connect[radius]");
                return -1;
        }

#ifndef CONFIG_NATIVE_WINDOWS
        switch (nserv->addr.af) {
        case AF_INET:
                claddrlen = sizeof(claddr);
                getsockname(sel_sock, (struct sockaddr *) &claddr, &claddrlen);
                wpa_printf(MSG_DEBUG, "RADIUS local address: %s:%u",
                           inet_ntoa(claddr.sin_addr), ntohs(claddr.sin_port));
                break;
#ifdef CONFIG_IPV6
        case AF_INET6: {
                claddrlen = sizeof(claddr6);
                getsockname(sel_sock, (struct sockaddr *) &claddr6,
                            &claddrlen);
                wpa_printf(MSG_DEBUG, "RADIUS local address: %s:%u",
                           inet_ntop(AF_INET6, &claddr6.sin6_addr,
                                     abuf, sizeof(abuf)),
                           ntohs(claddr6.sin6_port));
                break;
        }
#endif /* CONFIG_IPV6 */
        }
#endif /* CONFIG_NATIVE_WINDOWS */

        if (auth)
                radius->auth_sock = sel_sock;
        else
                radius->acct_sock = sel_sock;

        return 0;
}


static void radius_retry_primary_timer(void *eloop_ctx, void *timeout_ctx)
{
        struct radius_client_data *radius = eloop_ctx;
        struct hostapd_radius_servers *conf = radius->conf;
        struct hostapd_radius_server *oserv;

        if (radius->auth_sock >= 0 && conf->auth_servers &&
            conf->auth_server != conf->auth_servers) {
                oserv = conf->auth_server;
                conf->auth_server = conf->auth_servers;
                radius_change_server(radius, conf->auth_server, oserv,
                                     radius->auth_serv_sock,
                                     radius->auth_serv_sock6, 1);
        }

        if (radius->acct_sock >= 0 && conf->acct_servers &&
            conf->acct_server != conf->acct_servers) {
                oserv = conf->acct_server;
                conf->acct_server = conf->acct_servers;
                radius_change_server(radius, conf->acct_server, oserv,
                                     radius->acct_serv_sock,
                                     radius->acct_serv_sock6, 0);
        }

        if (conf->retry_primary_interval)
                eloop_register_timeout(conf->retry_primary_interval, 0,
                                       radius_retry_primary_timer, radius,
                                       NULL);
}


static int radius_client_disable_pmtu_discovery(int s)
{
        int r = -1;
#if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DONT)
        /* Turn off Path MTU discovery on IPv4/UDP sockets. */
        int action = IP_PMTUDISC_DONT;
        r = setsockopt(s, IPPROTO_IP, IP_MTU_DISCOVER, &action,
                       sizeof(action));
        if (r == -1)
                wpa_printf(MSG_ERROR, "Failed to set IP_MTU_DISCOVER: "
                           "%s", strerror(errno));
#endif
        return r;
}


static int radius_client_init_auth(struct radius_client_data *radius)
{
        struct hostapd_radius_servers *conf = radius->conf;
        int ok = 0;

        radius->auth_serv_sock = socket(PF_INET, SOCK_DGRAM, 0);
        if (radius->auth_serv_sock < 0)
                perror("socket[PF_INET,SOCK_DGRAM]");
        else {
                radius_client_disable_pmtu_discovery(radius->auth_serv_sock);
                ok++;
        }

#ifdef CONFIG_IPV6
        radius->auth_serv_sock6 = socket(PF_INET6, SOCK_DGRAM, 0);
        if (radius->auth_serv_sock6 < 0)
                perror("socket[PF_INET6,SOCK_DGRAM]");
        else
                ok++;
#endif /* CONFIG_IPV6 */

        if (ok == 0)
                return -1;

        radius_change_server(radius, conf->auth_server, NULL,
                             radius->auth_serv_sock, radius->auth_serv_sock6,
                             1);

        if (radius->auth_serv_sock >= 0 &&
            eloop_register_read_sock(radius->auth_serv_sock,
                                     radius_client_receive, radius,
                                     (void *) RADIUS_AUTH)) {
                printf("Could not register read socket for authentication "
                       "server\n");
                return -1;
        }

#ifdef CONFIG_IPV6
        if (radius->auth_serv_sock6 >= 0 &&
            eloop_register_read_sock(radius->auth_serv_sock6,
                                     radius_client_receive, radius,
                                     (void *) RADIUS_AUTH)) {
                printf("Could not register read socket for authentication "
                       "server\n");
                return -1;
        }
#endif /* CONFIG_IPV6 */

        return 0;
}


static int radius_client_init_acct(struct radius_client_data *radius)
{
        struct hostapd_radius_servers *conf = radius->conf;
        int ok = 0;

        radius->acct_serv_sock = socket(PF_INET, SOCK_DGRAM, 0);
        if (radius->acct_serv_sock < 0)
                perror("socket[PF_INET,SOCK_DGRAM]");
        else {
                radius_client_disable_pmtu_discovery(radius->acct_serv_sock);
                ok++;
        }

#ifdef CONFIG_IPV6
        radius->acct_serv_sock6 = socket(PF_INET6, SOCK_DGRAM, 0);
        if (radius->acct_serv_sock6 < 0)
                perror("socket[PF_INET6,SOCK_DGRAM]");
        else
                ok++;
#endif /* CONFIG_IPV6 */

        if (ok == 0)
                return -1;

        radius_change_server(radius, conf->acct_server, NULL,
                             radius->acct_serv_sock, radius->acct_serv_sock6,
                             0);

        if (radius->acct_serv_sock >= 0 &&
            eloop_register_read_sock(radius->acct_serv_sock,
                                     radius_client_receive, radius,
                                     (void *) RADIUS_ACCT)) {
                printf("Could not register read socket for accounting "
                       "server\n");
                return -1;
        }

#ifdef CONFIG_IPV6
        if (radius->acct_serv_sock6 >= 0 &&
            eloop_register_read_sock(radius->acct_serv_sock6,
                                     radius_client_receive, radius,
                                     (void *) RADIUS_ACCT)) {
                printf("Could not register read socket for accounting "
                       "server\n");
                return -1;
        }
#endif /* CONFIG_IPV6 */

        return 0;
}


/**
 * radius_client_init - Initialize RADIUS client
 * @ctx: Callback context to be used in hostapd_logger() calls
 * @conf: RADIUS client configuration (RADIUS servers)
 * Returns: Pointer to private RADIUS client context or %NULL on failure
 *
 * The caller is responsible for keeping the configuration data available for
 * the lifetime of the RADIUS client, i.e., until radius_client_deinit() is
 * called for the returned context pointer.
 */
struct radius_client_data *
radius_client_init(void *ctx, struct hostapd_radius_servers *conf)
{
        struct radius_client_data *radius;

        radius = os_zalloc(sizeof(struct radius_client_data));
        if (radius == NULL)
                return NULL;

        radius->ctx = ctx;
        radius->conf = conf;
        radius->auth_serv_sock = radius->acct_serv_sock =
                radius->auth_serv_sock6 = radius->acct_serv_sock6 =
                radius->auth_sock = radius->acct_sock = -1;

        if (conf->auth_server && radius_client_init_auth(radius)) {
                radius_client_deinit(radius);
                return NULL;
        }

        if (conf->acct_server && radius_client_init_acct(radius)) {
                radius_client_deinit(radius);
                return NULL;
        }

        if (conf->retry_primary_interval)
                eloop_register_timeout(conf->retry_primary_interval, 0,
                                       radius_retry_primary_timer, radius,
                                       NULL);

        return radius;
}


/**
 * radius_client_deinit - Deinitialize RADIUS client
 * @radius: RADIUS client context from radius_client_init()
 */
void radius_client_deinit(struct radius_client_data *radius)
{
        if (!radius)
                return;

        if (radius->auth_serv_sock >= 0)
                eloop_unregister_read_sock(radius->auth_serv_sock);
        if (radius->acct_serv_sock >= 0)
                eloop_unregister_read_sock(radius->acct_serv_sock);
#ifdef CONFIG_IPV6
        if (radius->auth_serv_sock6 >= 0)
                eloop_unregister_read_sock(radius->auth_serv_sock6);
        if (radius->acct_serv_sock6 >= 0)
                eloop_unregister_read_sock(radius->acct_serv_sock6);
#endif /* CONFIG_IPV6 */

        eloop_cancel_timeout(radius_retry_primary_timer, radius, NULL);

        radius_client_flush(radius, 0);
        os_free(radius->auth_handlers);
        os_free(radius->acct_handlers);
        os_free(radius);
}


/**
 * radius_client_flush_auth - Flush pending RADIUS messages for an address
 * @radius: RADIUS client context from radius_client_init()
 * @addr: MAC address of the related device
 *
 * This function can be used to remove pending RADIUS authentication messages
 * that are related to a specific device. The addr parameter is matched with
 * the one used in radius_client_send() call that was used to transmit the
 * authentication request.
 */
void radius_client_flush_auth(struct radius_client_data *radius,
                              const u8 *addr)
{
        struct radius_msg_list *entry, *prev, *tmp;

        prev = NULL;
        entry = radius->msgs;
        while (entry) {
                if (entry->msg_type == RADIUS_AUTH &&
                    os_memcmp(entry->addr, addr, ETH_ALEN) == 0) {
                        hostapd_logger(radius->ctx, addr,
                                       HOSTAPD_MODULE_RADIUS,
                                       HOSTAPD_LEVEL_DEBUG,
                                       "Removing pending RADIUS authentication"
                                       " message for removed client");

                        if (prev)
                                prev->next = entry->next;
                        else
                                radius->msgs = entry->next;

                        tmp = entry;
                        entry = entry->next;
                        radius_client_msg_free(tmp);
                        radius->num_msgs--;
                        continue;
                }

                prev = entry;
                entry = entry->next;
        }
}


static int radius_client_dump_auth_server(char *buf, size_t buflen,
                                          struct hostapd_radius_server *serv,
                                          struct radius_client_data *cli)
{
        int pending = 0;
        struct radius_msg_list *msg;
        char abuf[50];

        if (cli) {
                for (msg = cli->msgs; msg; msg = msg->next) {
                        if (msg->msg_type == RADIUS_AUTH)
                                pending++;
                }
        }

        return os_snprintf(buf, buflen,
                           "radiusAuthServerIndex=%d\n"
                           "radiusAuthServerAddress=%s\n"
                           "radiusAuthClientServerPortNumber=%d\n"
                           "radiusAuthClientRoundTripTime=%d\n"
                           "radiusAuthClientAccessRequests=%u\n"
                           "radiusAuthClientAccessRetransmissions=%u\n"
                           "radiusAuthClientAccessAccepts=%u\n"
                           "radiusAuthClientAccessRejects=%u\n"
                           "radiusAuthClientAccessChallenges=%u\n"
                           "radiusAuthClientMalformedAccessResponses=%u\n"
                           "radiusAuthClientBadAuthenticators=%u\n"
                           "radiusAuthClientPendingRequests=%u\n"
                           "radiusAuthClientTimeouts=%u\n"
                           "radiusAuthClientUnknownTypes=%u\n"
                           "radiusAuthClientPacketsDropped=%u\n",
                           serv->index,
                           hostapd_ip_txt(&serv->addr, abuf, sizeof(abuf)),
                           serv->port,
                           serv->round_trip_time,
                           serv->requests,
                           serv->retransmissions,
                           serv->access_accepts,
                           serv->access_rejects,
                           serv->access_challenges,
                           serv->malformed_responses,
                           serv->bad_authenticators,
                           pending,
                           serv->timeouts,
                           serv->unknown_types,
                           serv->packets_dropped);
}


static int radius_client_dump_acct_server(char *buf, size_t buflen,
                                          struct hostapd_radius_server *serv,
                                          struct radius_client_data *cli)
{
        int pending = 0;
        struct radius_msg_list *msg;
        char abuf[50];

        if (cli) {
                for (msg = cli->msgs; msg; msg = msg->next) {
                        if (msg->msg_type == RADIUS_ACCT ||
                            msg->msg_type == RADIUS_ACCT_INTERIM)
                                pending++;
                }
        }

        return os_snprintf(buf, buflen,
                           "radiusAccServerIndex=%d\n"
                           "radiusAccServerAddress=%s\n"
                           "radiusAccClientServerPortNumber=%d\n"
                           "radiusAccClientRoundTripTime=%d\n"
                           "radiusAccClientRequests=%u\n"
                           "radiusAccClientRetransmissions=%u\n"
                           "radiusAccClientResponses=%u\n"
                           "radiusAccClientMalformedResponses=%u\n"
                           "radiusAccClientBadAuthenticators=%u\n"
                           "radiusAccClientPendingRequests=%u\n"
                           "radiusAccClientTimeouts=%u\n"
                           "radiusAccClientUnknownTypes=%u\n"
                           "radiusAccClientPacketsDropped=%u\n",
                           serv->index,
                           hostapd_ip_txt(&serv->addr, abuf, sizeof(abuf)),
                           serv->port,
                           serv->round_trip_time,
                           serv->requests,
                           serv->retransmissions,
                           serv->responses,
                           serv->malformed_responses,
                           serv->bad_authenticators,
                           pending,
                           serv->timeouts,
                           serv->unknown_types,
                           serv->packets_dropped);
}


/**
 * radius_client_get_mib - Get RADIUS client MIB information
 * @radius: RADIUS client context from radius_client_init()
 * @buf: Buffer for returning MIB data in text format
 * @buflen: Maximum buf length in octets
 * Returns: Number of octets written into the buffer
 */
int radius_client_get_mib(struct radius_client_data *radius, char *buf,
                          size_t buflen)
{
        struct hostapd_radius_servers *conf = radius->conf;
        int i;
        struct hostapd_radius_server *serv;
        int count = 0;

        if (conf->auth_servers) {
                for (i = 0; i < conf->num_auth_servers; i++) {
                        serv = &conf->auth_servers[i];
                        count += radius_client_dump_auth_server(
                                buf + count, buflen - count, serv,
                                serv == conf->auth_server ?
                                radius : NULL);
                }
        }

        if (conf->acct_servers) {
                for (i = 0; i < conf->num_acct_servers; i++) {
                        serv = &conf->acct_servers[i];
                        count += radius_client_dump_acct_server(
                                buf + count, buflen - count, serv,
                                serv == conf->acct_server ?
                                radius : NULL);
                }
        }

        return count;
}