worker.c

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/*
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
 /**
 * $Id: cdd76e35a472d930710d3785bd0f0384d63aac9c $
 *
 * @brief Worker thread functions.
 * @file io/worker.c
 *
 *  The "worker" thread is the one responsible for the bulk of the
 *  work done when processing a request.  Workers are spawned by the
 *  scheduler, and create a kqueue (KQ) and control-plane
 *  Atomic Queue (AQ) for control-plane communication.
 *
 *  When a network thread discovers that it needs more workers, it
 *  asks the scheduler for a KQ/AQ combination.  The network thread
 *  then creates a channel dedicated to that worker, and sends the
 *  channel to the worker in a "new channel" message.  The worker
 *  receives the channel, and sends an ACK back to the network thread.
 *
 *  The network thread then sends the worker new packets, which the
 *  worker receives and processes.
 *
 *  When a packet is decoded, it is put into the "runnable" heap, and
 *  also into the timeout sublist. The main loop fr_worker() then
 *  pulls new requests off of this heap and runs them.  The main event
 *  loop checks the head of the timeout sublist, and forcefully terminates
 *  any requests which have been running for too long.
 *
 *  If a request is yielded, it is placed onto the yielded list in
 *  the worker "tracking" data structure.
 *
 * @copyright 2016 Alan DeKok (aland@freeradius.org)
 */
 
RCSID("$Id: cdd76e35a472d930710d3785bd0f0384d63aac9c $")
 
#define LOG_PREFIX worker->name
#define LOG_DST worker->log
 
#include <freeradius-devel/io/channel.h>
#include <freeradius-devel/io/listen.h>
#include <freeradius-devel/io/worker.h>
#include <freeradius-devel/unlang/base.h>
#include <freeradius-devel/util/minmax_heap.h>
#include <freeradius-devel/util/timer.h>
 
#include <stdalign.h>
 
#ifdef WITH_VERIFY_PTR
static void worker_verify(fr_worker_t *worker);
#define WORKER_VERIFY worker_verify(worker)
#else
#define WORKER_VERIFY
#endif
 
static _Atomic(uint64_t) request_number = 0;
 
FR_SLAB_TYPES(request, request_t)
FR_SLAB_FUNCS(request, request_t)
 
static _Thread_local fr_ring_buffer_t *fr_worker_rb;
 
typedef struct {
        fr_worker_t             *worker;        //!< the worker that owns this channel slot,
                                                ///< so channel callbacks can reach back without
                                                ///< threading `worker` through every layer.
        fr_channel_t            *ch;
        fr_message_set_t        *ms;            //!< messages for this channel
 
        fr_dlist_head_t         dlist;          //!< of requests received on this channel
} fr_worker_channel_t;
 
/**
 *  A worker which takes packets from a master, and processes them.
 */
struct fr_worker_s {
        char const              *name;          //!< name of this worker
        fr_worker_config_t      config;         //!< external configuration
 
        unlang_interpret_t      *intp;          //!< Worker's local interpreter.
 
        pthread_t               thread_id;      //!< my thread ID
 
        fr_log_t const          *log;           //!< log destination
        fr_log_lvl_t            lvl;            //!< log level
 
        fr_atomic_queue_t       *aq_control;    //!< atomic queue for control messages sent to me
 
        fr_control_t            *control;       //!< the control plane
 
        fr_event_list_t         *el;            //!< our event list
 
        int                     num_channels;   //!< actual number of channels
 
        fr_heap_t               *runnable;      //!< current runnable requests which we've spent time processing
 
        fr_timer_list_t         *timeout;               //!< Track when requests timeout using a dlist.
        fr_time_delta_t         max_request_time;       //!< maximum time a request can be processed
 
        fr_rb_tree_t            *dedup;         //!< de-dup tree
 
        fr_rb_tree_t            *listeners;     //!< so we can cancel requests when a listener goes away
 
        fr_io_stats_t           stats;          //!< input / output stats
        fr_time_elapsed_t       cpu_time;       //!< histogram of total CPU time per request
        fr_time_elapsed_t       wall_clock;     //!< histogram of wall clock time per request
 
        uint64_t                num_naks;       //!< number of messages which were nak'd
        uint64_t                num_active;     //!< number of active requests
 
        fr_time_delta_t         predicted;      //!< How long we predict a request will take to execute.
        fr_time_tracking_t      tracking;       //!< how much time the worker has spent doing things.
 
        bool                    was_sleeping;   //!< used to suppress multiple sleep signals in a row
        bool                    exiting;        //!< are we exiting?
 
        fr_worker_channel_t     *channel;       //!< list of channels
 
        request_slab_list_t     *slab;          //!< slab allocator for request_t
};
 
typedef struct {
        fr_listen_t const       *listener;      //!< incoming packets
 
        fr_rb_node_t            node;           //!< in tree of listeners
 
        /*
         *      To save time, we don't care about num_elements here.  Which means that we don't
         *      need to cache or lookup the fr_worker_listen_t when we free a request.
         */
        fr_dlist_head_t         dlist;          //!< of requests associated with this listener.
} fr_worker_listen_t;
 
 
static fr_cmp_ret_t worker_listener_cmp(void const *one, void const *two)
{
        fr_worker_listen_t const *a = one, *b = two;
 
        return CMP(a->listener, b->listener);
}
 
 
/*
 *      Explicitly cleanup the memory allocated to the ring buffer,
 *      just in case valgrind complains about it.
 */
static int _fr_worker_rb_free(void *arg)
{
        return talloc_free(arg);
}
 
/** Initialise thread local storage
 *
 * @return fr_ring_buffer_t for messages
 */
static inline fr_ring_buffer_t *fr_worker_rb_init(void)
{
        fr_ring_buffer_t *rb;
 
        rb = fr_worker_rb;
        if (rb) return rb;
 
        rb = fr_ring_buffer_create(NULL, FR_CONTROL_MAX_MESSAGES * FR_CONTROL_MAX_SIZE);
        if (!rb) {
                fr_perror("Failed allocating memory for worker ring buffer");
                return NULL;
        }
 
        fr_atexit_thread_local(fr_worker_rb, _fr_worker_rb_free, rb);
 
        return rb;
}
 
static inline bool is_worker_thread(fr_worker_t const *worker)
{
        return (pthread_equal(pthread_self(), worker->thread_id) != 0);
}
 
static void worker_request_bootstrap(fr_worker_channel_t *wc, fr_channel_data_t *cd, fr_time_t now);
static void worker_send_reply(fr_worker_t *worker, request_t *request, bool do_not_respond, fr_time_t now);
 
/** Callback which handles a message being received on the worker side.
 *
 * @param[in] ch the channel to drain
 * @param[in] cd the message (if any) to start with
 * @param[in] uctx the worker channel slot the message came in on
 */
static void worker_recv_request(fr_channel_t *ch, fr_channel_data_t *cd, void *uctx)
{
        fr_worker_channel_t *wc = uctx;
        fr_worker_t *worker = wc->worker;
 
        worker->stats.in++;
        DEBUG3("Received request %" PRIu64 "", worker->stats.in);
        cd->channel.ch = ch;
        worker_request_bootstrap(wc, cd, fr_time());
}
 
static void worker_requests_cancel(fr_worker_channel_t *ch)
{
        fr_async_t *async;
 
        while ((async = fr_dlist_pop_head(&ch->dlist)) != NULL) {
                unlang_interpret_signal(async->request, FR_SIGNAL_CANCEL);
        }
}
 
static void worker_exit(fr_worker_t *worker)
{
        worker->exiting = true;
 
        /*
         *      Don't allow the post event to run
         *      any more requests.  They'll be
         *      signalled to stop before we exit.
         *
         *      This only has an effect in single
         *      threaded mode.
         */
        (void)fr_event_post_delete(worker->el, fr_worker_post_event, worker);
}
 
/** Handle a control plane message sent to the worker via a channel
 *
 * @param[in] data      the message
 * @param[in] data_size size of the data
 * @param[in] now       the current time
 * @param[in] uctx      the worker
 */
static void worker_channel_callback(void const *data, size_t data_size, fr_time_t now, void *uctx)
{
        int                     i;
        unsigned int            num;
        bool                    ok, was_sleeping;
        fr_channel_t            *ch;
        fr_message_set_t        *ms;
        fr_channel_event_t      ce;
        fr_worker_t             *worker = uctx;
 
        was_sleeping = worker->was_sleeping;
        worker->was_sleeping = false;
 
        /*
         *      We were woken up by a signal to do something.  We're
         *      not sleeping.
         */
        ce = fr_channel_service_message(now, &ch, data, data_size);
        DEBUG3("Channel %s",
               fr_table_str_by_value(channel_signals, ce, "<INVALID>"));
        switch (ce) {
        case FR_CHANNEL_ERROR:
                return;
 
        case FR_CHANNEL_EMPTY:
                return;
 
        case FR_CHANNEL_NOOP:
                return;
 
        case FR_CHANNEL_DATA_READY_REQUESTOR:
                fr_assert(0 == 1);
                break;
 
        case FR_CHANNEL_DATA_READY_RESPONDER:
                fr_assert(ch != NULL);
 
                if (!fr_channel_recv_request(ch)) {
                        worker->was_sleeping = was_sleeping;
 
                } else while (fr_channel_recv_request(ch));
                break;
 
        case FR_CHANNEL_OPEN:
                fr_assert(ch != NULL);
 
                ok = false;
                for (i = 0; i < worker->config.max_channels; i++) {
                        fr_assert(worker->channel[i].ch != ch);
 
                        if (worker->channel[i].ch != NULL) continue;
 
                        worker->channel[i].worker = worker;
                        worker->channel[i].ch = ch;
                        fr_dlist_init(&worker->channel[i].dlist, fr_async_t, entry);
 
                        DEBUG3("Received channel %p into array entry %d", ch, i);
 
                        ms = fr_message_set_create(worker, worker->config.message_set_size,
                                                   sizeof(fr_channel_data_t),
                                                   worker->config.ring_buffer_size, false);
                        fr_assert(ms != NULL);
                        worker->channel[i].ms = ms;
 
                        /*
                         *      Hand the channel a pointer to the slot rather than to
                         *      any one field of it, so a callback holding only the
                         *      channel reaches the message set and the request list
                         *      alike.  Neither can be set in
                         *      fr_worker_channel_create() because the slot has not
                         *      been claimed at that point.
                         */
                        fr_channel_responder_uctx_add(ch, &worker->channel[i]);
                        fr_channel_set_recv_request(ch, worker_recv_request, &worker->channel[i]);
 
                        worker->num_channels++;
                        ok = true;
                        break;
                }
 
                fr_cond_assert(ok);
                break;
 
        case FR_CHANNEL_CLOSE:
                fr_assert(ch != NULL);
 
                ok = false;
 
                /*
                 *      Locate the signalling channel in the list
                 *      of channels.
                 */
                for (i = 0; i < worker->config.max_channels; i++) {
                        if (!worker->channel[i].ch) continue;
 
                        if (worker->channel[i].ch != ch) continue;
 
                        worker_requests_cancel(&worker->channel[i]);
 
                        ms = worker->channel[i].ms;
 
                        fr_assert_msg(fr_dlist_num_elements(&worker->channel[i].dlist) == 0,
                                      "Network added messages to channel after sending FR_CHANNEL_CLOSE");
 
                        /*
                         *      Should be nothing left: the network is not supposed
                         *      to enqueue anything once it has signalled the close,
                         *      which is what the assert above claims.  Hand back
                         *      whatever we find anyway, so the messages do not
                         *      strand the ring buffer they came from, and complain,
                         *      because these produce no reply and so the network
                         *      never decrements its outstanding count for them.
                         */
                        num = fr_channel_responder_discard(ch);
                        if (num > 0) PWARN("Discarded %u request(s) still queued at close", num);
 
                        fr_channel_responder_ack_close(ch);
                        fr_assert(ms != NULL);
                        fr_message_set_gc(ms);
                        talloc_free(ms);
 
                        worker->channel[i].ch = NULL;
 
                        fr_assert(fr_dlist_num_elements(&worker->channel[i].dlist) == 0);
                        fr_assert(worker->num_channels > 0);
 
                        worker->num_channels--;
                        ok = true;
                        break;
                }
 
                fr_cond_assert(ok);
 
                /*
                 *      Our last input channel closed,
                 *      time to die.
                 */
                if (worker->num_channels == 0) worker_exit(worker);
                break;
        }
}
 
static int fr_worker_listen_cancel_self(fr_worker_t *worker, fr_listen_t const *li)
{
        fr_worker_listen_t *wl;
        request_t *request;
 
        fr_rb_find((void **)&wl, worker->listeners, &(fr_worker_listen_t) { .listener = li });
        if (!wl) return -1;
 
        while ((request = fr_dlist_pop_head(&wl->dlist)) != NULL) {
                RERROR("Cancelling request due to socket being closed");
                unlang_interpret_signal(request, FR_SIGNAL_CANCEL);
        }
 
        (void) fr_rb_delete(worker->listeners, wl);
        talloc_free(wl);
 
        return 0;
}
 
 
/** A socket is going away, so clean up any requests which use this socket.
 *
 * @param[in] data      the message
 * @param[in] data_size size of the data
 * @param[in] now       the current time
 * @param[in] uctx      the worker
 */
static void worker_listen_cancel_callback(void const *data, NDEBUG_UNUSED size_t data_size, UNUSED fr_time_t now, void *uctx)
{
        fr_listen_t const       *li;
        fr_worker_t             *worker = uctx;
 
        fr_assert(data_size == sizeof(li));
 
        memcpy(&li, data, sizeof(li));
 
        (void) fr_worker_listen_cancel_self(worker, li);
}
 
/** Send a NAK to the network thread
 *
 * The network thread believes that a worker is running a request until that request has been NAK'd.
 * We typically NAK requests when they've been hanging around in the worker's backlog too long,
 * or there was an error executing the request.
 *
 * @param[in] worker    the worker
 * @param[in] cd        the message to NAK
 * @param[in] now       when the message is NAKd
 */
static void worker_nak(fr_worker_t *worker, fr_channel_data_t *cd, fr_time_t now)
{
        size_t                  size;
        fr_channel_data_t       *reply;
        fr_channel_t            *ch;
        fr_worker_channel_t     *wc;
        fr_message_set_t        *ms;
        fr_listen_t             *listen;
 
        worker->num_naks++;
 
        /*
         *      Cache the outbound channel.  We'll need it later.
         */
        ch = cd->channel.ch;
        listen = cd->listen;
 
        /*
         *      If the channel has been closed, but we haven't
         *      been informed, that is extremely bad.
         *
         *      Try to continue working... but we'll likely
         *      leak memory or SEGV soon.
         */
        if (!fr_cond_assert_msg(fr_channel_active(ch), "Wanted to send NAK but channel has been closed")) {
                fr_message_done(&cd->m);
                return;
        }
 
        wc = fr_channel_responder_uctx_get(ch);
        ms = wc->ms;
        fr_assert(ms != NULL);
 
        size = listen->app_io->default_reply_size;
        if (!size) size = listen->app_io->default_message_size;
 
        /*
         *      Allocate a default message size.
         */
        MEM(reply = (fr_channel_data_t *) fr_message_and_data_reserve(ms, size));
 
        /*
         *      Encode a NAK
         */
        if (listen->app_io->nak) {
                size = listen->app_io->nak(listen, cd->packet_ctx, cd->m.data,
                                           cd->m.data_size, reply->m.data, reply->m.rb_size);
        } else {
                size = 1;       /* rely on them to figure it the heck out */
        }
 
        (void) fr_message_and_data_commit(ms, &reply->m, size);
 
        /*
         *      Fill in the NAK.
         */
        reply->m.when = now;
        reply->reply.cpu_time = worker->tracking.running_total;
        reply->reply.processing_time = fr_time_delta_from_msec(1); /* @todo - set to something better? */
        reply->reply.request_time = cd->request.recv_time;
 
        reply->listen = cd->listen;
        reply->packet_ctx = cd->packet_ctx;
 
        /*
         *      Mark the original message as done.
         */
        fr_message_done(&cd->m);
 
        /*
         *      Send the reply, which also polls the request queue.
         */
        if (fr_channel_send_reply(ch, reply) < 0) {
                DEBUG2("Failed sending reply to channel");
        }
 
        worker->stats.out++;
}
 
/** Signal the unlang interpreter that it needs to stop running the request
 *
 * Signalling is a synchronous operation.  Whatever I/O requests the request
 * is currently performing are immediately cancelled, and all the frames are
 * popped off the unlang stack.
 *
 * Modules and unlang keywords explicitly register signal handlers to deal
 * with their yield points being cancelled/interrupted via this function.
 *
 * The caller should assume the request is no longer viable after calling
 * this function.
 *
 * @param[in] request   request to cancel.  The request may still run to completion.
 */
static void worker_stop_request(request_t *request)
{
        /*
         *      Also marks the request as done and runs
         *      the internal/external callbacs.
         */
        unlang_interpret_signal(request, FR_SIGNAL_CANCEL);
}
 
/** Enforce max_request_time
 *
 * Run periodically, and tries to clean up requests which were received by the network
 * thread more than max_request_time seconds ago.  In the interest of not adding a
 * timer for every packet, the requests are given a 1 second leeway.
 *
 * @param[in] tl        the worker's timer list.
 * @param[in] when      the current time
 * @param[in] uctx      the request_t timing out.
 */
static void _worker_request_timeout(UNUSED fr_timer_list_t *tl, UNUSED fr_time_t when, void *uctx)
{
        request_t       *request = talloc_get_type_abort(uctx, request_t);
 
        /*
         *      Waiting too long, delete it.
         */
        REDEBUG("Request has reached max_request_time - signalling it to stop");
        worker_stop_request(request);
 
        /*
         *      This ensures the finally section can run timeout specific policies
         */
        request->rcode = RLM_MODULE_TIMEOUT;
}
 
 
/** Start time tracking for a request, and mark it as runnable.
 *
 */
static int worker_request_time_tracking_start(fr_worker_t *worker, request_t *request, fr_time_t now)
{
        /*
         *      New requests are inserted into the time order heap in
         *      strict time priority.  Once they are in the list, they
         *      are only removed when the request is done / free'd.
         */
        fr_assert(!fr_timer_armed(request->timeout));
 
        if (unlikely(fr_timer_in(request, worker->timeout, &request->timeout, worker->config.max_request_time,
                                 true, _worker_request_timeout, request) < 0)) {
                RERROR("Failed to set request timeout timer");
                return -1;
        }
 
        /*
         *      Bootstrap the async state machine with the initial
         *      state of the request.
         */
        RDEBUG3("Time tracking started in yielded state");
        fr_time_tracking_start(&worker->tracking, &request->async->tracking, now);
        fr_time_tracking_yield(&request->async->tracking, now);
        worker->num_active++;
 
        fr_assert(!fr_heap_entry_inserted(request->runnable));
        (void) fr_heap_insert(&worker->runnable, request);
 
        return 0;
}
 
static void worker_request_time_tracking_end(fr_worker_t *worker, request_t *request, fr_time_t now)
{
        RDEBUG3("Time tracking ended");
        fr_time_tracking_end(&worker->predicted, &request->async->tracking, now);
        fr_assert(worker->num_active > 0);
        worker->num_active--;
 
        TALLOC_FREE(request->timeout);  /* Disarm the reques timer */
}
 
/** Send a response packet to the network side
 *
 * @param[in] worker            This worker.
 * @param[in] request           we're sending a reply for.
 * @param[in] send_reply        whether the network side sends a reply
 * @param[in] now               The current time
 */
static void worker_send_reply(fr_worker_t *worker, request_t *request, bool send_reply, fr_time_t now)
{
        fr_channel_data_t *reply;
        fr_channel_t *ch;
        fr_worker_channel_t *wc;
        fr_message_set_t *ms;
        size_t size = 1;
 
        REQUEST_VERIFY(request);
 
        /*
         *      If we're sending a reply, then it's no longer runnable.
         */
        fr_assert(!fr_heap_entry_inserted(request->runnable));
 
        if (send_reply) {
                size = request->async->listen->app_io->default_reply_size;
                if (!size) size = request->async->listen->app_io->default_message_size;
        }
 
        /*
         *      Allocate and send the reply.
         */
        ch = request->async->channel;
        fr_assert(ch != NULL);
 
        /*
         *      If the channel has been closed, but we haven't
         *      been informed, that is extremely bad.
         *
         *      Try to continue working... but we'll likely
         *      leak memory or SEGV soon.
         */
        if (!fr_cond_assert_msg(fr_channel_active(ch), "Wanted to send reply but channel has been closed")) {
                return;
        }
 
        wc = fr_channel_responder_uctx_get(ch);
        ms = wc->ms;
        fr_assert(ms != NULL);
 
        reply = (fr_channel_data_t *) fr_message_and_data_reserve(ms, size);
        fr_assert(reply != NULL);
 
        /*
         *      Encode it, if required.
         */
        if (send_reply) {
                ssize_t slen = 0;
                fr_listen_t const *listen = request->async->listen;
 
                if (listen->app_io->encode) {
                        slen = listen->app_io->encode(listen->app_io_instance, request,
                                                      reply->m.data, reply->m.rb_size);
                } else if (listen->app->encode) {
                        slen = listen->app->encode(listen->app_instance, request,
                                                   reply->m.data, reply->m.rb_size);
                }
                if (slen < 0) {
                        RPERROR("Failed encoding request");
                        *reply->m.data = 0;
                        slen = 1;
                }
 
                /*
                 *      Shrink the buffer to the actual packet size.
                 *
                 *      This will ALWAYS return the same message as we put in.
                 */
                fr_assert((size_t) slen <= reply->m.rb_size);
                (void) fr_message_and_data_commit(ms, &reply->m, slen);
        } else {
                (void) fr_message_and_data_commit(ms, &reply->m, 0);
        }
 
        /*
         *      Fill in the rest of the fields in the channel message.
         *
         *      sequence / ack will be filled in by fr_channel_send_reply()
         */
        reply->m.when = now;
        reply->reply.cpu_time = worker->tracking.running_total;
        reply->reply.processing_time = request->async->tracking.running_total;
        reply->reply.request_time = request->async->recv_time;
 
        reply->listen = request->async->listen;
        reply->packet_ctx = request->async->packet_ctx;
 
        /*
         *      Update the various timers.
         */
        fr_time_elapsed_update(&worker->cpu_time, now, fr_time_add(now, reply->reply.processing_time));
        fr_time_elapsed_update(&worker->wall_clock, reply->reply.request_time, now);
 
        RDEBUG("Finished request");
 
        /*
         *      Send the reply, which also polls the request queue.
         */
        if (fr_channel_send_reply(ch, reply) < 0) {
                /*
                 *      Should only happen if the TO_REQUESTOR
                 *      channel is full, or it's not yet active.
                 *
                 *      Not much we can do except complain
                 *      loudly and cleanup the request.
                 */
                RPERROR("Failed sending reply to network thread");
        }
 
        worker->stats.out++;
 
        fr_assert(!fr_timer_armed(request->timeout));
        fr_assert(!fr_heap_entry_inserted(request->runnable));
 
        fr_dlist_entry_unlink(&request->listen_entry);
 
#ifndef NDEBUG
        request->async->el = NULL;
        request->async->channel = NULL;
        request->async->packet_ctx = NULL;
        request->async->listen = NULL;
#endif
}
 
/*
 *      talloc_typed_asprintf() is horrifically slow for printing
 *      simple numbers.
 */
static char *itoa_internal(TALLOC_CTX *ctx, uint64_t number)
{
        char buffer[32];
        char *p;
        char const *numbers = "0123456789";
 
        p = buffer + 30;
        *(p--) = '\0';
 
        while (number > 0) {
                *(p--) = numbers[number % 10];
                number /= 10;
        }
 
        if (p[1]) return talloc_strdup(ctx, p + 1);
 
        return talloc_strdup(ctx, "0");
}
 
/** Initialize various request fields needed by the worker.
 *
 */
static inline CC_HINT(always_inline)
void worker_request_init(fr_worker_t *worker, request_t *request, fr_time_t now)
{
        /*
         *      For internal requests request->packet
         *      and request->reply are already populated.
         */
        if (!request->packet) MEM(request->packet = fr_packet_alloc(request, false));
        if (!request->reply) MEM(request->reply = fr_packet_alloc(request, false));
 
        request->packet->timestamp = now;
        request->async = talloc_zero(request, fr_async_t);
        request->async->request = request;
        request->async->recv_time = now;
        request->async->el = worker->el;
        fr_dlist_entry_init(&request->async->entry);
}
 
static inline CC_HINT(always_inline)
void worker_request_name_number(request_t *request)
{
        request->number = atomic_fetch_add_explicit(&request_number, 1, memory_order_seq_cst);
        if (request->name) talloc_const_free(request->name);
        request->name = itoa_internal(request, request->number);
}
 
static inline CC_HINT(always_inline)
uint32_t worker_num_requests(fr_worker_t *worker)
{
        return fr_timer_list_num_events(worker->timeout);
}
 
static int _worker_request_deinit(request_t *request, UNUSED void *uctx)
{
        return request_slab_deinit(request);
}
 
static void worker_request_bootstrap(fr_worker_channel_t *wc, fr_channel_data_t *cd, fr_time_t now)
{
        fr_worker_t             *worker = wc->worker;
        int                     ret = -1;
        request_t               *request;
        fr_listen_t             *listen = cd->listen;
 
        if (worker_num_requests(worker) >= (uint32_t) worker->config.max_requests) {
                RATE_LIMIT_GLOBAL(ERROR, "Worker at max requests");
                goto nak;
        }
 
        /*
         *      Receive a message to the worker queue, and decode it
         *      to a request.
         */
        fr_assert(listen != NULL);
 
        request = request_slab_reserve(worker->slab);
        if (!request) {
                RATE_LIMIT_GLOBAL(ERROR, "Worker failed allocating new request");
                goto nak;
        }
        /*
         *      Ensures that both the deinit function runs AND
         *      the request is returned to the slab if something
         *      calls talloc_free() on it.
         */
        request_slab_element_set_destructor(request, _worker_request_deinit, worker);
 
        /*
         *      Have to initialise the request manually because namspace
         *      changes based on the listener that allocated it.
         */
        if (request_init(request, REQUEST_TYPE_EXTERNAL,
                         (&(request_init_args_t){ .namespace = listen->dict })) < 0) {
                request_slab_release(request);
                goto nak;
        }
 
        /*
         *      Do normal worker init that's shared between internal
         *      and external requests.
         */
        worker_request_init(worker, request, now);
        worker_request_name_number(request);
 
        /*
         *      Associate our interpreter with the request
         */
        unlang_interpret_set(request, worker->intp);
 
        request->packet->timestamp = cd->request.recv_time; /* Legacy - Remove once everything looks at request->async */
 
        /*
         *      Update the transport-specific fields.
         */
        request->async->channel = cd->channel.ch;
 
        request->async->recv_time = cd->request.recv_time;
 
        request->async->listen = listen;
        request->async->packet_ctx = cd->packet_ctx;
        request->priority = cd->priority;
 
        /*
         *      Now that the "request" structure has been initialized, go decode the packet.
         *
         *      Note that this also sets the "async process" function.
         */
        if (listen->app->decode) {
                ret = listen->app->decode(listen->app_instance, request, cd->m.data, cd->m.data_size);
        } else if (listen->app_io->decode) {
                ret = listen->app_io->decode(listen->app_io_instance, request, cd->m.data, cd->m.data_size);
        }
 
        if (ret < 0) {
        fail:
                fr_assert(talloc_parent(request->stack) == request);
                request_slab_release(request);
 
        nak:
                worker_nak(worker, cd, now);
                return;
        }
 
        /*
         *      Set the entry point for this virtual server.
         */
        if (unlang_call_push(NULL, request, cd->listen->server_cs, UNLANG_TOP_FRAME) < 0) {
                RERROR("Protocol failed to set 'process' function");
                goto fail;
        }
 
        /*
         *      Look for conflicting / duplicate packets, but only if
         *      requested to do so.
         */
        if (request->async->listen->track_duplicates) {
                request_t *old;
 
                fr_rb_find((void **)&old, worker->dedup, request);
                if (!old) {
                        goto insert_new;
                }
 
                fr_assert(old->async->listen == request->async->listen);
                fr_assert(old->async->channel == request->async->channel);
 
                /*
                 *      There's a new packet.  Do we keep the old one,
                 *      or the new one?  This decision is made by
                 *      checking the recv_time, which is a
                 *      nanosecond-resolution timer.  If the time is
                 *      identical, then the new packet is the same as
                 *      the old one.
                 *
                 *      If the new packet is a duplicate of the old
                 *      one, then we can just discard the new one.  We
                 *      have to tell the channel that we've "eaten"
                 *      this reply, so the sequence number should
                 *      increase.
                 *
                 *      @todo - fix the channel code to do queue
                 *      depth, and not sequence / ack.
                 */
                if (fr_time_eq(old->async->recv_time, request->async->recv_time)) {
                        RWARN("Discarding duplicate of request (%"PRIu64")", old->number);
 
                        fr_channel_null_reply(request->async->channel);
                        request_slab_release(request);
 
                        /*
                         *      Signal there's a dup, and ignore the
                         *      return code.  We don't bother replying
                         *      here, as an FD event or timer will
                         *      wake up the request, and cause it to
                         *      continue.
                         *
                         *      @todo - the old request is NOT
                         *      running, but is yielded.  It MAY clean
                         *      itself up, or do something...
                         */
                        unlang_interpret_signal(old, FR_SIGNAL_DUP);
                        worker->stats.dup++;
 
                        fr_message_done(&cd->m);
                        return;
                }
 
                /*
                 *      Stop the old request, and decrement the number
                 *      of active requests.
                 */
                RWARN("Got conflicting packet for request (%" PRIu64 "), telling old request to stop", old->number);
 
                worker_stop_request(old);
                worker->stats.dropped++;
                (void) fr_rb_remove(NULL, worker->dedup, old); /* remove, but do NOT free it */
 
        insert_new:
                (void) fr_rb_insert(worker->dedup, request);
        }
 
        if (worker_request_time_tracking_start(worker, request, now) < 0) {
                if (request->async->listen->track_duplicates) (void) fr_rb_remove(NULL, worker->dedup, request);
                goto fail;
        }
 
        /*
         *      We're done with this message.
         */
        fr_message_done(&cd->m);
 
        {
                fr_worker_listen_t *wl;
 
                fr_rb_find((void **)&wl, worker->listeners, &(fr_worker_listen_t) { .listener = listen });
                if (!wl) {
                        MEM(wl = talloc_zero(worker, fr_worker_listen_t));
                        fr_dlist_init(&wl->dlist, request_t, listen_entry);
                        wl->listener = listen;
 
                        (void) fr_rb_insert(worker->listeners, wl);
                }
 
                fr_dlist_insert_tail(&wl->dlist, request);
        }
 
        /*
         *      Track this request against the channel it came in on so
         *      worker_requests_cancel() has something to walk when the
         *      network signals CHANNEL_CLOSE.
         */
        fr_dlist_insert_tail(&wc->dlist, request->async);
}
 
/**
 *  Track a request_t in the "runnable" heap.
 *  Higher priorities take precedence, followed by lower sequence numbers
 */
static fr_cmp_ret_t worker_runnable_cmp(void const *one, void const *two)
{
        request_t const *a = one, *b = two;
        int ret;
 
        /*
         *      Prefer higher priority packets.
         */
        ret = CMP_PREFER_LARGER(a->priority, b->priority);
        if (ret != 0) return ret;
 
        /*
         *      Prefer packets which are further along in their processing sequence.
         */
        ret = CMP_PREFER_LARGER(a->sequence, b->sequence);
        if (ret != 0) return ret;
 
        /*
         *      Smaller timestamp (i.e. earlier) is more important.
         */
        return fr_time_cmp(a->async->recv_time, b->async->recv_time);
}
 
/**
 *  Track a request_t in the "dedup" tree
 */
static fr_cmp_ret_t worker_dedup_cmp(void const *one, void const *two)
{
        int ret;
        request_t const *a = one, *b = two;
 
        ret = CMP(a->async->listen, b->async->listen);
        if (ret) return ret;
 
        return CMP(a->async->packet_ctx, b->async->packet_ctx);
}
 
/** Destroy a worker
 *
 * The input channels are signaled, and local messages are cleaned up.
 *
 * This should be called to _EXPLICITLY_ destroy a worker, when some fatal
 * error has occurred on the worker side, and we need to destroy it.
 *
 * We signal all pending requests in the backlog to stop, and tell the
 * network side that it should not send us any more requests.
 *
 * @param[in] worker the worker to destroy.
 */
void fr_worker_destroy(fr_worker_t *worker)
{
        int i, count, ret;
 
//      WORKER_VERIFY;
 
        /*
         *      Stop any new requests running with this interpreter
         */
        unlang_interpret_set_thread_default(NULL);
 
        /*
         *      Destroy all of the active requests.  These are ones
         *      which are still waiting for timers or file descriptor
         *      events.
         */
        count = 0;
 
        /*
         *      Force the timeout event to fire for all requests that
         *      are still running.
         */
        ret = fr_timer_list_force_run(worker->timeout);
        if (unlikely(ret < 0)) {
                fr_assert_msg(0, "Failed to force run the timeout list");
        } else {
                count += ret;
        }
 
        fr_assert(fr_heap_num_elements(worker->runnable) == 0);
 
        DEBUG("Worker is exiting - stopped %u requests", count);
 
        /*
         *      Signal the channels that we're closing.
         *
         *      The other end owns the channel, and will take care of
         *      popping messages in the TO_RESPONDER queue, and marking
         *      them FR_MESSAGE_DONE.  It will ignore the messages in
         *      the TO_REQUESTOR queue, as we own those.  They will be
         *      automatically freed when our talloc context is freed.
         */
        for (i = 0; i < worker->config.max_channels; i++) {
                if (!worker->channel[i].ch) continue;
 
                worker_requests_cancel(&worker->channel[i]);
 
                fr_assert_msg(fr_dlist_num_elements(&worker->channel[i].dlist) == 0,
                              "Pending messages in channel after cancelling request");
 
                fr_channel_responder_ack_close(worker->channel[i].ch);
        }
 
        talloc_free(worker);
}
 
/** Internal request (i.e. one generated by the interpreter) is now complete
 *
 */
static void _worker_request_internal_init(request_t *request, void *uctx)
{
        fr_worker_t     *worker = talloc_get_type_abort(uctx, fr_worker_t);
        fr_time_t       now = fr_time();
 
        worker_request_init(worker, request, now);
 
        /*
         *      Requests generated by the interpreter
         *      are always marked up as internal.
         */
        fr_assert(request_is_internal(request));
        if (worker_request_time_tracking_start(worker, request, now) < 0) {
                unlang_interpret_signal(request, FR_SIGNAL_CANCEL);
        }
}
 
 
/** External request is now complete
 *
 */
static void _worker_request_done_external(request_t *request, UNUSED rlm_rcode_t rcode, void *uctx)
{
        fr_worker_t     *worker = talloc_get_type_abort(uctx, fr_worker_t);
        fr_time_t       now = fr_time();
 
        /*
         *      All external requests MUST have a listener.
         */
        fr_assert(request_is_external(request));
        fr_assert(request->async->listen != NULL);
 
        /*
         *      Only real packets are in the dedup tree.  And even
         *      then, only some of the time.
         */
        if (request->async->listen->track_duplicates && fr_rb_node_inline_in_tree(&request->dedup_node)) {
                (void) fr_rb_delete(worker->dedup, request);
        }
 
        /*
         *      If we're running a real request, then the final
         *      indentation MUST be zero.  Otherwise we skipped
         *      something!
         *
         *      Also check that the request is NOT marked as
         *      "yielded", but is in fact done.
         *
         *      @todo - check that the stack is at frame 0, otherwise
         *      more things have gone wrong.
         */
        fr_assert_msg(request_is_internal(request) || request_is_detached(request) || (request->log.indent.unlang == 0),
                      "Request %s bad log indentation - expected 0 got %u", request->name, request->log.indent.unlang);
        fr_assert_msg(!unlang_interpret_is_resumable(request),
                      "Request %s is marked as yielded at end of processing", request->name);
        fr_assert_msg(unlang_interpret_stack_depth(request) == 0,
                      "Request %s stack depth %u > 0", request->name, unlang_interpret_stack_depth(request));
        RDEBUG("Done request");
 
        /*
         *      The request is done.  Track that.
         */
        worker_request_time_tracking_end(worker, request, now);
 
        /*
         *      Remove it from the list of requests associated with this channel.
         */
        if (fr_dlist_entry_in_list(&request->async->entry)) {
                fr_worker_channel_t *wc = fr_channel_responder_uctx_get(request->async->channel);
 
                fr_dlist_remove(&wc->dlist, request->async);
        }
 
        /*
         *      These conditions are true when the server is
         *      exiting and we're stopping all the requests.
         *
         *      This should never happen otherwise.
         */
        if (unlikely(!fr_channel_active(request->async->channel))) {
                fr_dlist_entry_unlink(&request->listen_entry);
                request_slab_release(request);
                return;
        }
 
        worker_send_reply(worker, request, !unlang_request_is_cancelled(request), now);
        request_slab_release(request);
}
 
/** Internal request (i.e. one generated by the interpreter) is now complete
 *
 * Whatever generated the request is now responsible for freeing it.
 */
static void _worker_request_done_internal(request_t *request, UNUSED rlm_rcode_t rcode, void *uctx)
{
        fr_worker_t     *worker = talloc_get_type_abort(uctx, fr_worker_t);
 
        worker_request_time_tracking_end(worker, request, fr_time());
 
        fr_assert(!fr_heap_entry_inserted(request->runnable));
        fr_assert(!fr_timer_armed(request->timeout));
        fr_assert(!fr_dlist_entry_in_list(&request->async->entry));
}
 
/** Detached request (i.e. one generated by the interpreter with no parent) is now complete
 *
 * As the request has no parent, then there's nothing to free it
 * so we have to.
 */
static void _worker_request_done_detached(request_t *request, UNUSED rlm_rcode_t rcode, UNUSED void *uctx)
{
        /*
         *      No time tracking for detached requests
         *      so we don't need to call
         *      worker_request_time_tracking_end.
         */
        fr_assert(!fr_heap_entry_inserted(request->runnable));
 
        /*
         *      Normally worker_request_time_tracking_end
         *      would remove the request from the time
         *      order heap, but we need to do that for
         *      detached requests.
         */
        TALLOC_FREE(request->timeout);
 
        fr_assert(!fr_dlist_entry_in_list(&request->async->entry));
 
        /*
         *      Detached requests have to be freed by us
         *      as nothing else can free them.
         *
         *      All other requests must be freed by the
         *      code which allocated them.
         */
        talloc_free(request);
}
 
 
/** Make us responsible for running the request
 *
 */
static void _worker_request_detach(request_t *request, void *uctx)
{
        fr_worker_t     *worker = talloc_get_type_abort(uctx, fr_worker_t);
        fr_time_t       now = fr_time();
 
        RDEBUG4("%s - Request detaching", __FUNCTION__);
 
        if (request_is_detachable(request)) {
                /*
                *       End the time tracking...  We don't track detached requests,
                *       because they don't contribute for the time consumed by an
                *       external request.
                */
                if (request->async->tracking.state == FR_TIME_TRACKING_YIELDED) {
                        RDEBUG3("Forcing time tracking to running state, from yielded, for request detach");
                        fr_time_tracking_resume(&request->async->tracking, now);
                }
                worker_request_time_tracking_end(worker, request, now);
 
                if (request_detach(request) < 0) RPEDEBUG("Failed detaching request");
 
                RDEBUG3("Request is detached");
        } else {
                fr_assert_msg(0, "Request is not detachable");
        }
 
        return;
}
 
/** Request is now runnable
 *
 */
static void _worker_request_runnable(request_t *request, void *uctx)
{
        fr_worker_t     *worker = uctx;
 
        RDEBUG4("%s - Request marked as runnable", __FUNCTION__);
        fr_heap_insert(&worker->runnable, request);
}
 
/** Interpreter yielded request
 *
 */
static void _worker_request_yield(request_t *request, UNUSED void *uctx)
{
        RDEBUG4("%s - Request yielded", __FUNCTION__);
        if (likely(!request_is_detached(request))) fr_time_tracking_yield(&request->async->tracking, fr_time());
}
 
/** Interpreter is starting to work on request again
 *
 */
static void _worker_request_resume(request_t *request, UNUSED void *uctx)
{
        RDEBUG4("%s - Request resuming", __FUNCTION__);
        if (likely(!request_is_detached(request))) fr_time_tracking_resume(&request->async->tracking, fr_time());
}
 
/** Check if a request is scheduled
 *
 */
static bool _worker_request_scheduled(request_t const *request, UNUSED void *uctx)
{
        return fr_heap_entry_inserted(request->runnable);
}
 
/** Update a request's priority
 *
 */
static void _worker_request_prioritise(request_t *request, void *uctx)
{
        fr_worker_t *worker = talloc_get_type_abort(uctx, fr_worker_t);
 
        RDEBUG4("%s - Request priority changed", __FUNCTION__);
 
        /* Extract the request from the runnable queue _if_ it's in the runnable queue */
        if (fr_heap_extract(&worker->runnable, request) < 0) return;
 
        /* Reinsert it to re-evaluate its new priority */
        fr_heap_insert(&worker->runnable, request);
}
 
/** Run a request
 *
 *  Until it either yields, or is done.
 *
 *  This function is also responsible for sending replies, and
 *  cleaning up the request.
 *
 * @param[in] worker the worker
 * @param[in] start the current time
 */
static inline CC_HINT(always_inline) void worker_run_request(fr_worker_t *worker, fr_time_t start)
{
        request_t       *request;
        fr_time_t       now;
 
        WORKER_VERIFY;
 
        now = start;
 
        /*
         *      Busy-loop running requests for 1ms.  We still poll the
         *      event loop 1000 times a second, OR when there's no
         *      more work to do.  This allows us to make progress with
         *      ongoing requests, at the expense of sometimes ignoring
         *      new ones.
         */
        while (fr_time_delta_lt(fr_time_sub(now, start), fr_time_delta_from_msec(1)) &&
               (fr_heap_pop((void **)&request, &worker->runnable) == 0) && request) {
 
                REQUEST_VERIFY(request);
                fr_assert(!fr_heap_entry_inserted(request->runnable));
 
                /*
                 *      For real requests, if the channel is gone,
                 *      just stop the request and free it.
                 */
                if (request->async->channel && !fr_channel_active(request->async->channel)) {
                        worker_stop_request(request);
                        continue;
                }
 
                (void)unlang_interpret(request, UNLANG_REQUEST_RESUME);
 
                now = fr_time();
        }
}
 
/** Create a worker
 *
 * @param[in] ctx the talloc context
 * @param[in] name the name of this worker
 * @param[in] el the event list
 * @param[in] logger the destination for all logging messages
 * @param[in] lvl log level
 * @param[in] config various configuration parameters
 * @return
 *      - NULL on error
 *      - fr_worker_t on success
 */
fr_worker_t *fr_worker_alloc(TALLOC_CTX *ctx, fr_event_list_t *el, char const *name, fr_log_t const *logger, fr_log_lvl_t lvl,
                             fr_worker_config_t *config)
{
        fr_worker_t *worker;
 
        worker = talloc_zero(ctx, fr_worker_t);
        if (!worker) {
nomem:
                fr_strerror_const("Failed allocating memory");
                return NULL;
        }
 
        worker->name = talloc_strdup(worker, name); /* thread locality */
 
        if (config) worker->config = *config;
 
#define CHECK_CONFIG(_x, _min, _max) do { \
                if (!worker->config._x) worker->config._x = _min; \
                if (worker->config._x < _min) worker->config._x = _min; \
                if (worker->config._x > _max) worker->config._x = _max; \
       } while (0)
 
#define CHECK_CONFIG_TIME_DELTA(_x, _min, _max) do { \
                if (fr_time_delta_lt(worker->config._x, _min)) worker->config._x = _min; \
                if (fr_time_delta_gt(worker->config._x, _max)) worker->config._x = _max; \
       } while (0)
 
        CHECK_CONFIG(max_requests,1024,(1 << 30));
        CHECK_CONFIG(max_channels, 64, 1024);
        CHECK_CONFIG(reuse.child_pool_size, 4096, 65536);
        CHECK_CONFIG(message_set_size, 1024, 8192);
        CHECK_CONFIG(ring_buffer_size, (1 << 17), (1 << 20));
        CHECK_CONFIG_TIME_DELTA(max_request_time, fr_time_delta_from_sec(5), fr_time_delta_from_sec(120));
 
        worker->channel = talloc_zero_array(worker, fr_worker_channel_t, worker->config.max_channels);
        if (!worker->channel) {
                talloc_free(worker);
                goto nomem;
        }
 
        worker->thread_id = pthread_self();
        worker->el = el;
        worker->log = logger;
        worker->lvl = lvl;
 
        /*
         *      The worker thread starts now.  Manually initialize it,
         *      because we're tracking request time, not the time that
         *      the worker thread is running.
         */
        memset(&worker->tracking, 0, sizeof(worker->tracking));
 
        worker->aq_control = fr_atomic_queue_talloc(worker, 1024);
        if (!worker->aq_control) {
                fr_strerror_const("Failed creating atomic queue");
        fail:
                talloc_free(worker);
                return NULL;
        }
 
        worker->control = fr_control_create(worker, el, worker->aq_control, 7);
        if (!worker->control) {
                fr_strerror_const_push("Failed creating control plane");
                goto fail;
        }
 
        if (fr_control_callback_add(&worker->control, FR_CONTROL_ID_CHANNEL, worker_channel_callback, worker) < 0) {
                fr_strerror_const_push("Failed adding control channel");
                goto fail;
        }
 
        if (fr_control_callback_add(&worker->control, FR_CONTROL_ID_LISTEN_DEAD, worker_listen_cancel_callback, worker) < 0) {
                fr_strerror_const_push("Failed adding callback for listeners");
                goto fail;
        }
 
        if (fr_control_open(worker->control) < 0) {
                fr_strerror_const_push("Failed opening control plane");
                goto fail;
        }
 
        worker->runnable = fr_heap_talloc_alloc(worker, worker_runnable_cmp, request_t, runnable, 0);
        if (!worker->runnable) {
                fr_strerror_const("Failed creating runnable heap");
                goto fail;
        }
 
        worker->timeout = fr_timer_list_ordered_alloc(worker, el->tl);
        if (!worker->timeout) {
                fr_strerror_const("Failed creating timeouts list");
                goto fail;
        }
 
        worker->dedup = fr_rb_inline_talloc_alloc(worker, request_t, dedup_node, worker_dedup_cmp, NULL);
        if (!worker->dedup) {
                fr_strerror_const("Failed creating de_dup tree");
                goto fail;
        }
 
        worker->listeners = fr_rb_inline_talloc_alloc(worker, fr_worker_listen_t, node, worker_listener_cmp, NULL);
        if (!worker->listeners) {
                fr_strerror_const("Failed creating listener tree");
                goto fail;
        }
 
        worker->intp = unlang_interpret_init(worker, el,
                                             &(unlang_request_func_t){
                                                        .init_internal = _worker_request_internal_init,
 
                                                        .done_external = _worker_request_done_external,
                                                        .done_internal = _worker_request_done_internal,
                                                        .done_detached = _worker_request_done_detached,
 
                                                        .detach = _worker_request_detach,
                                                        .yield = _worker_request_yield,
                                                        .resume = _worker_request_resume,
                                                        .mark_runnable = _worker_request_runnable,
 
                                                        .scheduled = _worker_request_scheduled,
                                                        .prioritise = _worker_request_prioritise
                                             },
                                             worker);
        if (!worker->intp){
                fr_strerror_const("Failed initialising interpreter");
                goto fail;
        }
 
        {
                if (!worker->config.reuse.child_pool_size) worker->config.reuse.child_pool_size = REQUEST_POOL_SIZE;
                if (!worker->config.reuse.num_children) worker->config.reuse.num_children = REQUEST_POOL_NUM_OBJECTS;
 
                if (!(worker->slab = request_slab_list_alloc(worker, el, &worker->config.reuse, NULL, NULL,
                                                             UNCONST(void *, worker), true, false))) {
                        fr_strerror_const("Failed creating request slab list");
                        goto fail;
                }
        }
 
        unlang_interpret_set_thread_default(worker->intp);
 
        return worker;
}
 
 
/** The main loop and entry point of the stand-alone worker thread.
 *
 *  Where there is only one thread, the event loop runs fr_worker_pre_event() and fr_worker_post_event()
 *  instead, And then fr_worker_post_event() takes care of calling worker_run_request() to actually run the
 *  request.
 *
 * @param[in] worker the worker data structure to manage
 */
void fr_worker(fr_worker_t *worker)
{
        WORKER_VERIFY;
 
        while (true) {
                bool wait_for_event;
                int num_events;
 
                WORKER_VERIFY;
 
                /*
                 *      There are runnable requests.  We still service
                 *      the event loop, but we don't wait for events.
                 */
                wait_for_event = (fr_heap_num_elements(worker->runnable) == 0);
                if (wait_for_event) {
                        if (worker->exiting && (worker_num_requests(worker) == 0)) break;
 
                        DEBUG4("Ready to process requests");
                }
 
                /*
                 *      Check the event list.  If there's an error
                 *      (e.g. exit), we stop looping and clean up.
                 */
                DEBUG4("Gathering events - %s", wait_for_event ? "will wait" : "Will not wait");
                num_events = fr_event_corral(worker->el, fr_time(), wait_for_event);
                if (num_events < 0) {
                        if (fr_event_loop_exiting(worker->el)) {
                                DEBUG4("Event loop exiting");
                                break;
                        }
 
                        PERROR("Failed retrieving events");
                        break;
                }
 
                DEBUG4("%u event(s) pending", num_events);
 
                /*
                 *      Service outstanding events.
                 */
                if (num_events > 0) {
                        DEBUG4("Servicing event(s)");
                        fr_event_service(worker->el);
                }
 
                /*
                 *      Run any outstanding requests.
                 */
                worker_run_request(worker, fr_time());
        }
}
 
/** Pre-event handler
 *
 *      This should be run ONLY in single-threaded mode!
 */
int fr_worker_pre_event(UNUSED fr_time_t now, UNUSED fr_time_delta_t wake, void *uctx)
{
        fr_worker_t *worker = talloc_get_type_abort(uctx, fr_worker_t);
        request_t *request;
 
        request = fr_heap_peek(worker->runnable);
        if (!request) return 0;
 
        /*
         *      There's work to do.  Tell the event handler to poll
         *      for IO / timers, but also immediately return to the
         *      calling function, which has more work to do.
         */
        return 1;
}
 
 
/** Post-event handler
 *
 *      This should be run ONLY in single-threaded mode!
 */
void fr_worker_post_event(UNUSED fr_event_list_t *el, UNUSED fr_time_t now, void *uctx)
{
        fr_worker_t *worker = talloc_get_type_abort(uctx, fr_worker_t);
 
        worker_run_request(worker, fr_time());  /* Event loop time can be too old, and trigger asserts */
}
 
/** Print debug information about the worker structure
 *
 * @param[in] worker the worker
 * @param[in] fp the file where the debug output is printed.
 */
void fr_worker_debug(fr_worker_t *worker, FILE *fp)
{
        WORKER_VERIFY;
 
        fprintf(fp, "\tnum_channels = %d\n", worker->num_channels);
        fprintf(fp, "\tstats.in = %" PRIu64 "\n", worker->stats.in);
 
        fprintf(fp, "\tcalculated (predicted) total CPU time = %" PRIu64 "\n",
                fr_time_delta_unwrap(worker->predicted) * worker->stats.in);
        if (worker->stats.in) {
                fprintf(fp, "\tcalculated (counted) per request time = %" PRIu64 "\n",
                        fr_time_delta_unwrap(worker->tracking.running_total) / worker->stats.in);
        }
 
        fr_time_tracking_debug(&worker->tracking, fp);
 
}
 
/** Create a channel to the worker
 *
 * Called by the master (i.e. network) thread when it needs to create
 * a new channel to a particuler worker.
 *
 * @param[in] worker the worker
 * @param[in] master the control plane of the master
 * @param[in] ctx the context in which the channel will be created
 */
fr_channel_t *fr_worker_channel_create(fr_worker_t *worker, TALLOC_CTX *ctx, fr_control_t *master)
{
        fr_channel_t *ch;
        pthread_t id;
        bool same;
 
        WORKER_VERIFY;
 
        id = pthread_self();
        same = (pthread_equal(id, worker->thread_id) != 0);
 
        ch = fr_channel_create(ctx, master, worker->control, same);
        if (!ch) return NULL;
 
 
        /*
         *      Tell the worker about the channel
         */
        if (fr_channel_signal_open(ch) < 0) {
                talloc_free(ch);
                return NULL;
        }
 
        return ch;
}
 
int fr_worker_listen_cancel(fr_worker_t *worker, fr_listen_t const *li)
{
        fr_ring_buffer_t *rb;
 
        /*
         *      Skip a bunch of work if we're already in the worker thread.
         */
        if (is_worker_thread(worker)) {
                return fr_worker_listen_cancel_self(worker, li);
        }
 
        rb = fr_worker_rb_init();
        if (!rb) return -1;
 
        return fr_control_message_send(worker->control, rb, FR_CONTROL_ID_LISTEN_DEAD, &li, sizeof(li));
}
 
#ifdef WITH_VERIFY_PTR
/** Verify the worker data structures.
 *
 * @param[in] worker the worker
 */
static void worker_verify(fr_worker_t *worker)
{
        int i;
 
        (void) talloc_get_type_abort(worker, fr_worker_t);
        fr_atomic_queue_verify(worker->aq_control);
 
        fr_assert(worker->control != NULL);
        (void) talloc_get_type_abort(worker->control, fr_control_t);
 
        fr_assert(worker->el != NULL);
        (void) talloc_get_type_abort(worker->el, fr_event_list_t);
 
        fr_assert(worker->runnable != NULL);
        (void) talloc_get_type_abort(worker->runnable, fr_heap_t);
 
        fr_assert(worker->dedup != NULL);
        (void) talloc_get_type_abort(worker->dedup, fr_rb_tree_t);
 
        for (i = 0; i < worker->config.max_channels; i++) {
                if (!worker->channel[i].ch) continue;
 
                (void) talloc_get_type_abort(worker->channel[i].ch, fr_channel_t);
        }
}
#endif
 
int fr_worker_stats(fr_worker_t const *worker, int num, uint64_t *stats)
{
        if (num < 0) return -1;
        if (num == 0) return 0;
 
        stats[0] = worker->stats.in;
        if (num >= 2) stats[1] = worker->stats.out;
        if (num >= 3) stats[2] = worker->stats.dup;
        if (num >= 4) stats[3] = worker->stats.dropped;
        if (num >= 5) stats[4] = worker->num_naks;
        if (num >= 6) stats[5] = worker->num_active;
 
        if (num <= 6) return num;
 
        return 6;
}
 
static int cmd_stats_worker(FILE *fp, UNUSED FILE *fp_err, void *ctx, fr_cmd_info_t const *info)
{
        fr_worker_t const *worker = ctx;
        fr_time_delta_t when;
 
        if ((info->argc == 0) || (strcmp(info->argv[0], "count") == 0)) {
                fprintf(fp, "count.in\t\t\t%" PRIu64 "\n", worker->stats.in);
                fprintf(fp, "count.out\t\t\t%" PRIu64 "\n", worker->stats.out);
                fprintf(fp, "count.dup\t\t\t%" PRIu64 "\n", worker->stats.dup);
                fprintf(fp, "count.dropped\t\t\t%" PRIu64 "\n", worker->stats.dropped);
                fprintf(fp, "count.naks\t\t\t%" PRIu64 "\n", worker->num_naks);
                fprintf(fp, "count.active\t\t\t%" PRIu64 "\n", worker->num_active);
                fprintf(fp, "count.runnable\t\t\t%u\n", fr_heap_num_elements(worker->runnable));
        }
 
        if ((info->argc == 0) || (strcmp(info->argv[0], "cpu") == 0)) {
                when = worker->predicted;
                fprintf(fp, "cpu.request_time_rtt\t\t%.9f\n", fr_time_delta_unwrap(when) / (double)NSEC);
 
                when = worker->tracking.running_total;
                if (fr_time_delta_ispos(when) && (worker->stats.in > worker->stats.dropped)) {
                        when = fr_time_delta_div(when, fr_time_delta_wrap(worker->stats.in - worker->stats.dropped));
                }
                fprintf(fp, "cpu.average_request_time\t%.9f\n", fr_time_delta_unwrap(when) / (double)NSEC);
 
                when = worker->tracking.running_total;
                fprintf(fp, "cpu.used\t\t\t%.6f\n", fr_time_delta_unwrap(when) / (double)NSEC);
 
                when = worker->tracking.waiting_total;
                fprintf(fp, "cpu.waiting\t\t\t%.3f\n", fr_time_delta_unwrap(when) / (double)NSEC);
 
                fr_time_elapsed_fprint(fp, &worker->cpu_time, "cpu.requests", 4);
                fr_time_elapsed_fprint(fp, &worker->wall_clock, "time.requests", 4);
        }
 
        return 0;
}
 
fr_cmd_table_t cmd_worker_table[] = {
        {
                .parent = "stats",
                .name = "worker",
                .help = "Statistics for workers threads.",
                .read_only = true
        },
 
        {
                .parent = "stats worker",
                .add_name = true,
                .name = "self",
                .syntax = "[(count|cpu)]",
                .func = cmd_stats_worker,
                .help = "Show statistics for a specific worker thread.",
                .read_only = true
        },
 
        CMD_TABLE_END
};