modules/ratelimit/ratelimit.c

/*
 * $Id$
 *
 * ratelimit module
 *
 * Copyright (C) 2006 Hendrik Scholz <hscholz@raisdorf.net>
 * Copyright (C) 2008-2010 Ovidiu Sas <osas@voipembedded.com>
 *
 * This file is part of Kamailio, a free SIP server.
 *
 * Kamailio 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
 *
 * Kamailio 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * History:
 * ---------
 *
 * 2008-01-10 ported from SER project (osas)
 * 2008-01-16 ported enhancements from openims project (osas)
 * 2020-04-28 add sip-router rpc interface (osas)
 */

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <regex.h>
#include <math.h>


#include "../../mem/mem.h"
#include "../../mem/shm_mem.h"
#include "../../sr_module.h"
#include "../../dprint.h"
#include "../../timer.h"
#include "../../timer_ticks.h"
#include "../../ut.h"
#include "../../locking.h"
#include "../../mod_fix.h"
#include "../../data_lump.h"
#include "../../data_lump_rpl.h"
#include "../../lib/kcore/statistics.h"
#include "../../rpc_lookup.h"


MODULE_VERSION

#define MAX_PIPES       16
#define MAX_QUEUES      10

/*
 * timer interval length in seconds, tunable via modparam
 */
#define RL_TIMER_INTERVAL 10

#define RXLS(m, str, i) (int)((m)[i].rm_eo - (m)[i].rm_so), (str) + (m)[i].rm_so
#define RXL(m, str, i) (int)((m)[i].rm_eo - (m)[i].rm_so)
#define RXS(m, str, i) (str) + (m)[i].rm_so

static inline int str_cmp(const str * a, const str * b);
static inline int str_i_cmp(const str * a, const str * b);

typedef struct str_map {
        str     str;
        int     id;
} str_map_t;

static int str_map_str(const str_map_t * map, const str * key, int * ret);
static int str_map_int(const str_map_t * map, int key, str * ret);

/* PIPE_ALGO_FEEDBACK holds cpu usage to a fixed value using 
 * negative feedback according to the PID controller model
 *
 * <http://en.wikipedia.org/wiki/PID_controller>
 */
enum {
        PIPE_ALGO_NOP = 0,
        PIPE_ALGO_RED,
        PIPE_ALGO_TAILDROP,
        PIPE_ALGO_FEEDBACK,
        PIPE_ALGO_NETWORK
};

str_map_t algo_names[] = {
        {str_init("NOP"),       PIPE_ALGO_NOP},
        {str_init("RED"),       PIPE_ALGO_RED},
        {str_init("TAILDROP"),  PIPE_ALGO_TAILDROP},
        {str_init("FEEDBACK"),  PIPE_ALGO_FEEDBACK},
        {str_init("NETWORK"),   PIPE_ALGO_NETWORK},
        {{0, 0},                0},
};


/* at jiri@iptel.org's suggestion:
 *
 * set this to 'cpu' to have openser look at /proc/stat every time_interval
 * or set it to 'external' and you can push data in from an external source
 * via the fifo interface
 */
enum {
        LOAD_SOURCE_CPU,
        LOAD_SOURCE_EXTERNAL
};

str_map_t source_names[] = {
        {str_init("cpu"),       LOAD_SOURCE_CPU},
        {str_init("external"),  LOAD_SOURCE_EXTERNAL},
        {{0, 0},                0},
};


typedef struct pipe {
        /* stuff that gets read as a modparam or set via fifo */
        int *   algo;
        int             algo_mp;
        int *   limit;
        int             limit_mp;

        /* updated values */
        int *   counter;
        int *   last_counter;
        int *   load;
} pipe_t;

typedef struct rl_queue {
        int     *       pipe;
        int             pipe_mp;
        str     *       method;
        str             method_mp;
} rl_queue_t;

static struct timer_ln* rl_timer;

/* === these change after startup */
gen_lock_t * rl_lock;

static double * load_value;     /* actual load, used by PIPE_ALGO_FEEDBACK */
static double * pid_kp, * pid_ki, * pid_kd, * pid_setpoint; /* PID tuning params */
static int * drop_rate;         /* updated by PIPE_ALGO_FEEDBACK */

static int * network_load_value;      /* network load */

/* where to get the load for feedback. values: cpu, external */
static int load_source_mp = LOAD_SOURCE_CPU;
static int * load_source;

typedef struct pipe_params {
        int no;
        int algo;
        int limit;
} pipe_params_t;

typedef struct rl_queue_params {
        int pipe;
        str method;
} rl_queue_params_t;

static pipe_t pipes[MAX_PIPES];
static rl_queue_t queues[MAX_QUEUES];

static int nqueues_mp = 0;
static int * nqueues;

static  str * rl_dbg_str = NULL;

/* these only change in the mod_init() process -- no locking needed */
static int timer_interval = RL_TIMER_INTERVAL;
static int cfg_setpoint;        /* desired load, used when reading modparams */
/* === */

#ifndef RL_DEBUG_LOCKS
# define LOCK_GET lock_get
# define LOCK_RELEASE lock_release
#else
# define LOCK_GET(l) do { \
        LM_INFO("%d: + get\n", __LINE__); \
        lock_get(l); \
        LM_INFO("%d: - get\n", __LINE__); \
} while (0)

# define LOCK_RELEASE(l) do { \
        LM_INFO("%d: + release\n", __LINE__); \
        lock_release(l); \
        LM_INFO("%d: - release\n", __LINE__); \
} while (0)
#endif

static int params_inited = 0;
static regex_t pipe_params_regex;
static regex_t queue_params_regex;

static int mod_init(void);
static ticks_t rl_timer_handle(ticks_t, struct timer_ln*, void*);
static int w_rl_check_default(struct sip_msg*, char *, char *);
static int w_rl_check_forced(struct sip_msg*, char *, char *);
static int w_rl_check_forced_pipe(struct sip_msg*, char *, char *);
static int add_queue_params(modparam_t, void *);
static int add_pipe_params(modparam_t, void *);
/* RESERVED for future use
static int set_load_source(modparam_t, void *);
*/
static void destroy(void);

static cmd_export_t cmds[]={
        {"rl_check",      (cmd_function)w_rl_check_default,     0, 0,               0,               REQUEST_ROUTE|LOCAL_ROUTE},
        {"rl_check",      (cmd_function)w_rl_check_forced,      1, fixup_pvar_null,
                fixup_free_pvar_null, REQUEST_ROUTE|LOCAL_ROUTE},
        {"rl_check_pipe", (cmd_function)w_rl_check_forced_pipe, 1, fixup_uint_null, 0,               REQUEST_ROUTE|LOCAL_ROUTE},
        {0,0,0,0,0,0}
};
static param_export_t params[]={
        {"timer_interval", INT_PARAM,                &timer_interval},
        {"queue",          STR_PARAM|USE_FUNC_PARAM, (void *)add_queue_params},
        {"pipe",           STR_PARAM|USE_FUNC_PARAM, (void *)add_pipe_params},
        /* RESERVED for future use
        {"load_source",    STR_PARAM|USE_FUNC_PARAM, (void *)set_load_source},
        */
        {0,0,0}
};

static rpc_export_t rpc_methods[];

struct module_exports exports= {
        "ratelimit",
        DEFAULT_DLFLAGS,                /* dlopen flags */
        cmds,
        params,
        0,                              /* exported statistics */
        0,                              /* exported MI functions */
        0,                              /* exported pseudo-variables */
        0,                              /* extra processes */
        mod_init,                       /* module initialization function */
        0,
        (destroy_function) destroy,     /* module exit function */
        0                               /* per-child init function */
};


static int str_map_str(const str_map_t * map, const str * key, int * ret)
{
        for (; map->str.s; map++) 
                if (! str_cmp(&map->str, key)) {
                        *ret = map->id;
                        return 0;
                }
        LM_DBG("str_map_str() failed map=%p key=%.*s\n", map, key->len, key->s);
        return -1;
}

static int str_map_int(const str_map_t * map, int key, str * ret)
{
        for (; map->str.s; map++) 
                if (map->id == key) {
                        *ret = map->str;
                        return 0;
                }
        LM_DBG("str_map_str() failed map=%p key=%d\n", map, key);
        return -1;
}

static int str_cpy(str * dest, str * src)
{
        dest->len = src->len;
        dest->s = shm_malloc(src->len);
        if (! dest->s) {
                LM_ERR("oom: '%.*s'\n", src->len, src->s);
                return -1;
        }
        memcpy(dest->s, src->s, src->len);
        return 0;
}

/* not using /proc/loadavg because it only works when our_timer_interval == theirs */
static int get_cpuload(double * load)
{
        static 
        long long o_user, o_nice, o_sys, o_idle, o_iow, o_irq, o_sirq, o_stl;
        long long n_user, n_nice, n_sys, n_idle, n_iow, n_irq, n_sirq, n_stl;
        static int first_time = 1;
        FILE * f = fopen("/proc/stat", "r");

        if (! f) {
                LM_ERR("could not open /proc/stat\n");
                return -1;
        }
        if (fscanf(f, "cpu  %lld%lld%lld%lld%lld%lld%lld%lld",
                        &n_user, &n_nice, &n_sys, &n_idle, &n_iow, &n_irq, &n_sirq, &n_stl) < 0) {
                  LM_ERR("could not parse load informations\n");
                  return -1;
        }
        fclose(f);

        if (first_time) {
                first_time = 0;
                *load = 0;
        } else {                
                long long d_total =     (n_user - o_user)       + 
                                        (n_nice - o_nice)       + 
                                        (n_sys  - o_sys)        + 
                                        (n_idle - o_idle)       + 
                                        (n_iow  - o_iow)        + 
                                        (n_irq  - o_irq)        + 
                                        (n_sirq - o_sirq)       + 
                                        (n_stl  - o_stl);
                long long d_idle =      (n_idle - o_idle);

                *load = 1.0 - ((double)d_idle) / (double)d_total;
        }

        o_user  = n_user; 
        o_nice  = n_nice; 
        o_sys   = n_sys; 
        o_idle  = n_idle; 
        o_iow   = n_iow; 
        o_irq   = n_irq; 
        o_sirq  = n_sirq; 
        o_stl   = n_stl;
        
        return 0;
}

static double int_err = 0.0;
static double last_err = 0.0;

/* (*load_value) is expected to be in the 0.0 - 1.0 range
 * (expects rl_lock to be taken)
 */
static void do_update_load(void)
{
        static char spcs[51];
        int load;
        double err, dif_err, output;

        /* PID update */
        err = *pid_setpoint - *load_value;

        dif_err = err - last_err;

        /*
         * TODO?: the 'if' is needed so low cpu loads for 
         * long periods (which can't be compensated by 
         * negative drop rates) don't confuse the controller
         *
         * NB: - "err < 0" means "desired_cpuload < actual_cpuload"
         *     - int_err is integral(err) over time
         */
        if (int_err < 0 || err < 0)
                int_err += err;

        output =        (*pid_kp) * err + 
                                (*pid_ki) * int_err + 
                                (*pid_kd) * dif_err;
        last_err = err;

        *drop_rate = (output > 0) ? output  : 0;

        load = 0.5 + 100.0 * *load_value; /* round instead of floor */

        memset(spcs, '-', load / 4);
        spcs[load / 4] = 0;

        /*
        LM_DBG("p=% 6.2lf i=% 6.2lf d=% 6.2lf o=% 6.2lf %s|%d%%\n",
                err, int_err, dif_err, output, spcs, load);
        */
}

static void update_cpu_load(void)
{
        if (get_cpuload(load_value)) 
                return;

        do_update_load();
}

/* initialize ratelimit module */
static int mod_init(void)
{
        int i;

        if (rpc_register_array(rpc_methods)!=0) {
                LM_ERR("failed to register RPC commands\n");
                return -1;
        }

        rl_lock = lock_alloc();
        if (! rl_lock) {
                LM_ERR("oom in lock_alloc()\n");
                return -1;
        }

        if (lock_init(rl_lock)==0) {
                LM_ERR("failed to init lock\n");
                return -1;
        }

        /* register timer to reset counters */
        if ((rl_timer = timer_alloc()) == NULL) {
                LM_ERR("could not allocate timer\n");
                return -1;
        }
        timer_init(rl_timer, rl_timer_handle, 0, F_TIMER_FAST);
        timer_add(rl_timer, MS_TO_TICKS(1000*timer_interval));

        network_load_value = shm_malloc(sizeof(int));
        if (network_load_value==NULL) {
                LM_ERR("oom for network_load_value\n");
                return -1;
        }

        load_value = shm_malloc(sizeof(double));
        if (load_value==NULL) {
                LM_ERR("oom for load_value\n");
                return -1;
        }
        load_source = shm_malloc(sizeof(int));
        if (load_source==NULL) {
                LM_ERR("oom for load_source\n");
                return -1;
        }
        pid_kp = shm_malloc(sizeof(double));
        if (pid_kp==NULL) {
                LM_ERR("oom for pid_kp\n");
                return -1;
        }
        pid_ki = shm_malloc(sizeof(double));
        if (pid_ki==NULL) {
                LM_ERR("oom for pid_ki\n");
                return -1;
        }
        pid_kd = shm_malloc(sizeof(double));
        if (pid_kd==NULL) {
                LM_ERR("oom for pid_kd\n");
                return -1;
        }
        pid_setpoint = shm_malloc(sizeof(double));
        if (pid_setpoint==NULL) {
                LM_ERR("oom for pid_setpoint\n");
                return -1;
        }
        drop_rate = shm_malloc(sizeof(int));
        if (drop_rate==NULL) {
                LM_ERR("oom for drop_rate\n");
                return -1;
        }
        nqueues = shm_malloc(sizeof(int));
        if (nqueues==NULL) {
                LM_ERR("oom for nqueues\n");
                return -1;
        }
        rl_dbg_str = shm_malloc(sizeof(str));
        if (rl_dbg_str==NULL) {
                LM_ERR("oom for rl_dbg_str\n");
                return -1;
        }

        *network_load_value = 0;
        *load_value = 0.0;
        *load_source = load_source_mp;
        *pid_kp = 0.0;
        *pid_ki = -25.0;
        *pid_kd = 0.0;
        *pid_setpoint = 0.01 * (double)cfg_setpoint;
        *drop_rate      = 0;
        *nqueues = nqueues_mp;
        rl_dbg_str->s = NULL;
        rl_dbg_str->len = 0;

        for (i=0; i<MAX_PIPES; i++) {
                pipes[i].algo    = shm_malloc(sizeof(int));
                if (pipes[i].algo==NULL) {
                        LM_ERR("oom for pipes[%d].algo\n", i);
                        return -1;
                }
                pipes[i].limit   = shm_malloc(sizeof(int));
                if (pipes[i].limit==NULL) {
                        LM_ERR("oom for pipes[%d].limit\n", i);
                        return -1;
                }
                pipes[i].load    = shm_malloc(sizeof(int));
                if (pipes[i].load==NULL) {
                        LM_ERR("oom for pipes[%d].load\n", i);
                        return -1;
                }
                pipes[i].counter = shm_malloc(sizeof(int));
                if (pipes[i].counter==NULL) {
                        LM_ERR("oom for pipes[%d].counter\n", i);
                        return -1;
                }
                pipes[i].last_counter = shm_malloc(sizeof(int));
                if (pipes[i].last_counter==NULL) {
                        LM_ERR("oom for pipes[%d].last_counter\n", i);
                        return -1;
                }
                *pipes[i].algo    = pipes[i].algo_mp;
                *pipes[i].limit   = pipes[i].limit_mp;
                *pipes[i].load    = 0;
                *pipes[i].counter = 0;
                *pipes[i].last_counter = 0;
        }

        for (i=0; i<*nqueues; i++) {
                queues[i].pipe   = shm_malloc(sizeof(int));
                if (queues[i].pipe==NULL) {
                        LM_ERR("oom for queues[%d].pipe\n", i);
                        return -1;
                }
                queues[i].method = shm_malloc(sizeof(str));
                if (queues[i].method==NULL) {
                        LM_ERR("oom for queues[%d].method\n", i);
                        return -1;
                }

                *queues[i].pipe   = queues[i].pipe_mp;
                if (queues[i].method_mp.s == NULL) {
                        LM_ERR("unexpected NULL method for queues[%d].method_mp\n", i);
                        return -1;
                }
                if(str_cpy(queues[i].method, &queues[i].method_mp)) {
                        LM_ERR("oom str_cpy(queues[%d].method\n", i);
                        return -1;
                }
                pkg_free(queues[i].method_mp.s);
                queues[i].method_mp.s = NULL;
                queues[i].method_mp.len = 0;
        }

        return 0;
}


static void destroy(void)
{
        int i;

        regfree(&pipe_params_regex);
        regfree(&queue_params_regex);

        for (i=0;  i<MAX_PIPES; i++) {
                if (pipes[i].algo) {
                        shm_free(pipes[i].algo);
                        pipes[i].algo = NULL;
                }
                if (pipes[i].load) {
                        shm_free(pipes[i].load);
                        pipes[i].load = NULL;
                }
                if (pipes[i].counter) {
                        shm_free(pipes[i].counter);
                        pipes[i].counter = NULL;
                }
                if (pipes[i].last_counter) {
                        shm_free(pipes[i].last_counter);
                        pipes[i].last_counter = NULL;
                }
                if (pipes[i].limit) {
                        shm_free(pipes[i].limit);
                        pipes[i].limit = NULL;
                }
        }

        if (nqueues) {
                for (i=0; i<*nqueues; i++) {
                        if (queues[i].pipe) {
                                shm_free(queues[i].pipe);
                                queues[i].pipe = NULL;
                        }
                        if (queues[i].method) {
                                if (queues[i].method->s) {
                                        shm_free(queues[i].method->s);
                                        queues[i].method->s = NULL;
                                        queues[i].method->len = 0;
                                }
                                shm_free(queues[i].method);
                                queues[i].method = NULL;
                        }
                }
        }

        if (network_load_value) {
                shm_free(network_load_value);
                network_load_value = NULL;
        }
        if (load_value) {
                shm_free(load_value);
                load_value = NULL;
        }
        if (load_source) {
                shm_free(load_source);
                load_source = NULL;
        }
        if (pid_kp) {
                shm_free(pid_kp);
                pid_kp= NULL;
        }
        if (pid_ki) {
                shm_free(pid_ki);
                pid_ki = NULL;
        }
        if (pid_kd) {
                shm_free(pid_kd);
                pid_kd = NULL;
        }
        if (pid_setpoint) {
                shm_free(pid_setpoint);
                pid_setpoint = NULL;
        }
        if (drop_rate) {
                shm_free(drop_rate);
                drop_rate = NULL;
        }
        if (nqueues) {
                shm_free(nqueues);
                nqueues = NULL;
        }
        if (rl_dbg_str) {
                if (rl_dbg_str->s) {
                        shm_free(rl_dbg_str->s);
                        rl_dbg_str->s = NULL;
                        rl_dbg_str->len = 0;
                }
                shm_free(rl_dbg_str);
                rl_dbg_str = NULL;
        }

        if (rl_timer) {
                timer_free(rl_timer);
                rl_timer = NULL;
        }

        if (rl_lock) {
                lock_destroy(rl_lock);
                lock_dealloc((void *)rl_lock);
        }
}


static inline int str_cmp(const str * a , const str * b)
{
        return ! (a->len == b->len && ! strncmp(a->s, b->s, a->len));
}

static inline int str_i_cmp(const str * a, const str * b)
{
        return ! (a->len == b->len && ! strncasecmp(a->s, b->s, a->len));
}

str queue_other = str_init("*");

static int find_queue(struct sip_msg * msg, int * queue)
{
        str method = msg->first_line.u.request.method;
        int i;

        *queue = -1;
        for (i=0; i<*nqueues; i++)
                if (! str_i_cmp(queues[i].method, &method)) {
                        *queue = i;
                        return 0;
                } else if (! str_i_cmp(queues[i].method, &queue_other)) {
                        *queue = i;
                }
        
        if (*queue >= 0)
                return 0;
        
        LM_INFO("no queue matches\n");
        return -1;
}

/* this is here to avoid using rand() ... which doesn't _always_ return
 * exactly what we want (see NOTES section in 'man 3 rand')
 */
int hash[100] = {18, 50, 51, 39, 49, 68, 8, 78, 61, 75, 53, 32, 45, 77, 31, 
        12, 26, 10, 37, 99, 29, 0, 52, 82, 91, 22, 7, 42, 87, 43, 73, 86, 70, 
        69, 13, 60, 24, 25, 6, 93, 96, 97, 84, 47, 79, 64, 90, 81, 4, 15, 63, 
        44, 57, 40, 21, 28, 46, 94, 35, 58, 11, 30, 3, 20, 41, 74, 34, 88, 62, 
        54, 33, 92, 76, 85, 5, 72, 9, 83, 56, 17, 95, 55, 80, 98, 66, 14, 16, 
        38, 71, 23, 2, 67, 36, 65, 27, 1, 19, 59, 89, 48};


static int pipe_push(struct sip_msg * msg, int id)
{
        int ret;

        (*pipes[id].counter)++;

        switch (*pipes[id].algo) {
                case PIPE_ALGO_NOP:
                        LM_ERR("no algorithm defined for pipe %d\n", id);
                        ret = 1;
                        break;
                case PIPE_ALGO_TAILDROP:
                        ret = (*pipes[id].counter <= *pipes[id].limit * timer_interval) ? 1 : -1;
                        break;
                case PIPE_ALGO_RED:
                        if (*pipes[id].load == 0)
                                ret = 1;
                        else
                                ret = (! (*pipes[id].counter % *pipes[id].load)) ? 1 : -1;
                        break;
                case PIPE_ALGO_FEEDBACK:
                        ret = (hash[*pipes[id].counter % 100] < *drop_rate) ? -1 : 1;
                        break;
                case PIPE_ALGO_NETWORK:
                        ret = -1 * *pipes[id].load;
                        break;
                default:
                        LM_ERR("unknown ratelimit algorithm: %d\n", *pipes[id].algo);
                        ret = 1;
        }

        return ret;     
}

static int rl_check(struct sip_msg * msg, int forced_pipe)
{
        int que_id, pipe_id, ret;
        str method = msg->first_line.u.request.method;

        if (forced_pipe >=0 && (forced_pipe>=MAX_PIPES || *pipes[forced_pipe].algo==PIPE_ALGO_NOP)) {
                LM_ERR("forced pipe %d out of range or not defined", forced_pipe);
                return -1;
        }

        LOCK_GET(rl_lock);
        if (forced_pipe < 0) { 
                if (find_queue(msg, &que_id)) {
                        pipe_id = que_id = 0;
                        ret = -1;
                        goto out_release;
                }
                pipe_id = *queues[que_id].pipe;
        } else {
                que_id = 0;
                pipe_id = forced_pipe;
        }

        ret = pipe_push(msg, pipe_id);
out_release:
        LOCK_RELEASE(rl_lock);

        /* no locks here because it's only read and pipes[pipe_id] is always alloc'ed */
        LM_DBG("meth=%.*s queue=%d pipe=%d algo=%d limit=%d pkg_load=%d counter=%d "
                "load=%2.1lf network_load=%d => %s\n",
                method.len, method.s, que_id, pipe_id,
                *pipes[pipe_id].algo, *pipes[pipe_id].limit,
                *pipes[pipe_id].load, *pipes[pipe_id].counter,
                *load_value, *network_load_value, (ret == 1) ? "ACCEPT" : "DROP");

        return ret;
}

static int w_rl_check_forced(struct sip_msg* msg, char *p1, char *p2)
{
        int pipe = -1;
        pv_value_t pv_val;

        if (p1 && (pv_get_spec_value(msg, (pv_spec_t *)p1, &pv_val) == 0)) {
                if (pv_val.flags & PV_VAL_INT) {
                        pipe = pv_val.ri;
                        LM_DBG("pipe=%d\n", pipe);
                } else if (pv_val.flags & PV_VAL_STR) {
                        if(str2int(&(pv_val.rs), (unsigned int*)&pipe) != 0) {
                                LM_ERR("Unable to get pipe from pv '%.*s'"
                                        "=> defaulting to method type checking\n",
                                        pv_val.rs.len, pv_val.rs.s);
                                pipe = -1;
                        }
                } else {
                        LM_ERR("pv not a str or int => defaulting to method type checking\n");
                        pipe = -1;
                }
        } else {
                LM_ERR("Unable to get pipe from pv:%p"
                        " => defaulting to method type checking\n", p1);
                pipe = -1;
        }
        return rl_check(msg, pipe);
}
static int w_rl_check_forced_pipe(struct sip_msg* msg, char *p1, char *p2)
{
        int pipe;

        pipe = (int)(unsigned int)(unsigned long)p1;
        LM_DBG("trying pipe %d\n", pipe);
        return rl_check(msg, pipe);
}

static int w_rl_check_default(struct sip_msg* msg, char *p1, char *p2)
{
        return rl_check(msg, -1);
}

/* RESERVED for future use
static int set_load_source(modparam_t type, void * val)
{
        str src_name = { .s = val, .len = strlen(val) };
        int src_id;

        if (str_map_str(source_names, &src_name, &src_id)) {
                LM_ERR("unknown load source: %.*s\n", src_name.len, src_name.s);
                return -1;
        }

        load_source_mp = src_id;
        LM_INFO("switched to load source: %.*s\n", src_name.len, src_name.s);

        return 0;
}
*/

static int init_params(void)
{
        if (regcomp(&pipe_params_regex, "^([0-9]+):([^: ]+):([0-9]+)$", REG_EXTENDED|REG_ICASE) ||
                regcomp(&queue_params_regex, "^([0-9]+):([^: ]+)$", REG_EXTENDED|REG_ICASE)) {
                LM_ERR("can't compile modparam regexes\n");
                return -1;
        }

        memset(pipes, 0, sizeof(pipes));
        memset(queues, 0, sizeof(queues));

        params_inited = 1;
        return 0;
}


static int parse_pipe_params(char * line, pipe_params_t * params)
{
        regmatch_t m[4];
        str algo_str;

        if (! params_inited && init_params())
                return -1;
        if (regexec(&pipe_params_regex, line, 4, m, 0)) {
                LM_ERR("invalid param tuple: %s\n", line);
                return -1;
        }
        LM_DBG("pipe: [%.*s|%.*s|%.*s]\n",
                RXLS(m, line, 1), RXLS(m, line, 2), RXLS(m, line, 3));
        
        params->no = atoi(RXS(m, line, 1));
        params->limit = atoi(RXS(m, line, 3));

        algo_str.s   = RXS(m, line, 2);
        algo_str.len = RXL(m, line, 2);
        if (str_map_str(algo_names, &algo_str, &params->algo))
                return -1;

        return 0;
}

static int parse_queue_params(char * line, rl_queue_params_t * params)
{
        regmatch_t m[3];
        int len;

        if (! params_inited && init_params())
                return -1;
        if (regexec(&queue_params_regex, line, 3, m, 0)) {
                LM_ERR("invalid param tuple: %s\n", line);
                return -1;
        }
        LM_DBG("queue: [%.*s|%.*s]\n",
                RXLS(m, line, 1), RXLS(m, line, 2));
        
        params->pipe = atoi(RXS(m, line, 1));

        len = RXL(m, line, 2);
        params->method.s = (char *)pkg_malloc(len+1);
        if (params->method.s == 0) {
                LM_ERR("no memory left for method in params\n");
                return -1;
        }
        params->method.len = len;
        memcpy(params->method.s, RXS(m, line, 2), len+1);

        return 0;
}

static int check_feedback_setpoints(int modparam)
{
        int i, sp;

        cfg_setpoint = -1;

        for (i=0; i<MAX_PIPES; i++)
                if (pipes[i].algo_mp == PIPE_ALGO_FEEDBACK) {
                        sp = modparam ? pipes[i].limit_mp : *pipes[i].limit;

                        if (sp < 0 || sp > 100) {
                                LM_ERR("FEEDBACK cpu load must be >=0 and <= 100\n");
                                return -1;
                        } else if (cfg_setpoint == -1) {
                                cfg_setpoint = sp;
                        } else if (sp != cfg_setpoint) {
                                LM_ERR("pipe %d: FEEDBACK cpu load values must "
                                        "be equal for all pipes\n", i);
                                return -1;
                        }
                }

        return 0;
}


static int add_pipe_params(modparam_t type, void * val)
{
        char * param_line = val;
        pipe_params_t params;

        if (parse_pipe_params(param_line, &params))
                return -1;
        
        if (params.no < 0 || params.no >= MAX_PIPES) {
                LM_ERR("pipe number %d not allowed (MAX_PIPES=%d, 0-based)\n",
                        params.no, MAX_PIPES);
                return -1;
        }

        pipes[params.no].algo_mp = params.algo;
        pipes[params.no].limit_mp = params.limit;

        return check_feedback_setpoints(1);
}

static int add_queue_params(modparam_t type, void * val)
{
        char * param_line = val;
        rl_queue_params_t params;

        if (nqueues_mp >= MAX_QUEUES) {
                LM_ERR("MAX_QUEUES reached (%d)\n", MAX_QUEUES);
                return -1;
        }

        if (parse_queue_params(param_line, &params))
                return -1;

        if (params.pipe >= MAX_PIPES) {
                LM_ERR("pipe number %d not allowed (MAX_PIPES=%d, 0-based)\n",
                        params.pipe, MAX_PIPES);
                return -1;
        }

        queues[nqueues_mp].pipe_mp = params.pipe;
        queues[nqueues_mp].method_mp = params.method;
        nqueues_mp++;

        return 0;
}


/* timer housekeeping, invoked each timer interval to reset counters */
static ticks_t rl_timer_handle(ticks_t ticks, struct timer_ln* tl, void* data)
{
        int i, len;
        char *c, *p;

        LOCK_GET(rl_lock);
        switch (*load_source) {
                case LOAD_SOURCE_CPU:
                        update_cpu_load();
                        break;
        }

        *network_load_value = get_total_bytes_waiting();

        if (rl_dbg_str->s) {
                c = p = rl_dbg_str->s;
                memset(c, ' ', rl_dbg_str->len);
                for (i=0; i<MAX_PIPES; i++) {
                        c = int2str(*pipes[i].counter, &len);
                        if (len < 4) {
                                memcpy( p + (5-len), c, len );
                        } else {
                                memset(p, '*', 5);
                                LM_WARN("Counter pipes[%d] to big: %d\n",
                                        i, *pipes[i].counter);
                        }
                        p = p + 5;
                }
                LM_WARN("%.*s\n", rl_dbg_str->len, rl_dbg_str->s);
        }

        for (i=0; i<MAX_PIPES; i++) {
                if( *pipes[i].algo == PIPE_ALGO_NETWORK ) {
                        *pipes[i].load = ( *network_load_value > *pipes[i].limit ) ? 1 : -1;
                } else if (*pipes[i].limit && timer_interval) {
                        *pipes[i].load = *pipes[i].counter / (*pipes[i].limit * timer_interval);
                }
                *pipes[i].last_counter = *pipes[i].counter;
                *pipes[i].counter = 0;
        }
        LOCK_RELEASE(rl_lock);
        return (ticks_t)(-1); /* periodical */
}


/* rpc function documentation */
static const char *rpc_stats_doc[2] = {
        "Print ratelimit statistics: PIPE[<pipe_id>]: \
<last_counter>/<pipe_limit> (drop rate: <drop_rate>)", 0
};

static const char *rpc_get_pipes_doc[2] = {
        "Print pipes info: PIPE[<pipe_id>]: \
<pipe_algo_id>:<pipe_algo> <last_counter>/<pipe_limit> (drop rate: <drop_rate>) [<current_counter>]", 0
};

static const char *rpc_set_pipe_doc[2] = {
        "Sets a pipe params: <pipe_id> <pipe_algorithm> <pipe_limit>", 0
};

static const char *rpc_get_queues_doc[2] = {
        "Print queues info: QUEUE[queue_id]: <pipe_id>:<queue_method>", 0
};

static const char *rpc_set_queue_doc[2] = {
        "Sets queue params: <quue_id> <queue_method> <pipe_id>", 0
};

static const char *rpc_get_pid_doc[2] = {
        "Print PID Controller parameters for the FEEDBACK algorithm: \
<ki> <kp> <kd>", 0
};

static const char *rpc_set_pid_doc[2] = {
        "Sets the PID Controller parameters for the FEEDBACK algorithm: \
<ki> <kp> <kd>", 0
};

static const char *rpc_push_load_doc[2] = {
        "Force the value of the load parameter for FEEDBACK algorithm: \
<load>", 0
};

static const char *rpc_set_dbg_doc[2] = {
        "Sets the ratelimit debug/monitoing logs: 0-off 1-on", 0
};


/* rpc function implementations */
static void rpc_stats(rpc_t *rpc, void *c) {
        int i;

        LOCK_GET(rl_lock);
        for (i=0; i<MAX_PIPES; i++) {
                if (rpc->printf(c, "PIPE[%d]: %d/%d (drop rate: %d)",
                        i, *pipes[i].last_counter, *pipes[i].limit,
                        *pipes[i].load) < 0) goto error;
        }
error:
        LOCK_RELEASE(rl_lock);
}

static void rpc_get_pipes(rpc_t *rpc, void *c) {
        str algo;
        int i;

        LOCK_GET(rl_lock);
        for (i=0; i<MAX_PIPES; i++) {
                if (*pipes[i].algo != PIPE_ALGO_NOP) {
                        if (str_map_int(algo_names, *pipes[i].algo, &algo))
                                goto error;
                        if (rpc->printf(c, "PIPE[%d]: %d:%.*s %d/%d (drop rate: %d) [%d]",
                                i, *pipes[i].algo, algo.len, algo.s,
                                *pipes[i].last_counter, *pipes[i].limit,
                                *pipes[i].load, *pipes[i].counter) < 0) goto error;
                }
        }
error:
        LOCK_RELEASE(rl_lock);
}

static void rpc_set_pipe(rpc_t *rpc, void *c) {
        int pipe_no = MAX_PIPES, algo_id, limit = 0;
        str algo_str;

        if (rpc->scan(c, "dSd", &pipe_no, &algo_str, &limit) < 3) return;

        if (str_map_str(algo_names, &algo_str, &algo_id)) {
                LM_ERR("unknown algorithm: '%.*s'\n", algo_str.len, algo_str.s);
                rpc->fault(c, 400, "Unknown algorithm");
                return;
        }

        LM_DBG("set_pipe: %d:%d:%d\n", pipe_no, algo_id, limit);

        if (pipe_no >= MAX_PIPES || pipe_no < 0) {
                LM_ERR("wrong pipe_no: %d\n", pipe_no);
                rpc->fault(c, 400, "Unknown pipe");
                return;
        }

        LOCK_GET(rl_lock);
        *pipes[pipe_no].algo = algo_id;
        *pipes[pipe_no].limit = limit;

        if (check_feedback_setpoints(0)) {
                LM_ERR("feedback limits don't match\n");
                rpc->fault(c, 400, "Feedback limits don't match");
        } else {
                *pid_setpoint = 0.01 * (double)cfg_setpoint;
        }

        LOCK_RELEASE(rl_lock);
}

static void rpc_get_queues(rpc_t *rpc, void *c) {
        int i;

        LOCK_GET(rl_lock);
        for (i=0; i<MAX_QUEUES; i++) {
                if (queues[i].pipe) {
                        if (rpc->printf(c, "QUEUE[%d]: %d:%.*s",
                                i, *queues[i].pipe,
                                (*queues[i].method).len,
                                (*queues[i].method).s) < 0) goto error;
                }
        }
error:
        LOCK_RELEASE(rl_lock);
}

static void rpc_set_queue(rpc_t *rpc, void *c) {
        unsigned int queue_no = MAX_QUEUES, pipe_no = MAX_PIPES;
        str method, method_buf;


        if (rpc->scan(c, "dSd", &queue_no, &method, &pipe_no) < 3) return;

        if (pipe_no >= MAX_PIPES || pipe_no < 0) {
                LM_ERR("Invalid pipe number: %d\n", pipe_no);
                rpc->fault(c, 400, "Invalid pipe number");
                return;
        }

        if (str_cpy(&method_buf, &method)) {
                LM_ERR("out of memory\n");
                rpc->fault(c, 400, "OOM");
                return;
        }

        LOCK_GET(rl_lock);
        if (queue_no >= *nqueues) {
                LM_ERR("MAX_QUEUES reached for queue: %d\n", queue_no);
                rpc->fault(c, 400, "MAX_QUEUES reached");
                LOCK_RELEASE(rl_lock);
                return;
        }

        *queues[queue_no].pipe = pipe_no;
        if (!queues[queue_no].method->s)
                shm_free(queues[queue_no].method->s);
        queues[queue_no].method->s = method_buf.s;
        queues[queue_no].method->len = method_buf.len;
        LOCK_RELEASE(rl_lock);
}

static void rpc_get_pid(rpc_t *rpc, void *c) {
        rpc->printf(c, "ki[%f] kp[%f] kd[%f] ", *pid_ki, *pid_kp, *pid_kd);
}

static void rpc_set_pid(rpc_t *rpc, void *c) {
        double ki, kp, kd;

        if (rpc->scan(c, "fff", &ki, &kp, &kd) < 3) return;

        LOCK_GET(rl_lock);
        *pid_ki = ki;
        *pid_kp = kp;
        *pid_kd = kd;
        LOCK_RELEASE(rl_lock);
}


static void rpc_push_load(rpc_t *rpc, void *c) {
        double value;

        if (rpc->scan(c, "f", &value) < 1) return;

        if (value < 0.0 || value > 1.0) {
                LM_ERR("value out of range: %0.3f in not in [0.0,1.0]\n", value);
                rpc->fault(c, 400, "Value out of range");
                return;
        }
        LOCK_GET(rl_lock);
        *load_value = value;
        LOCK_RELEASE(rl_lock);

        do_update_load();
}

static void rpc_set_dbg(rpc_t *rpc, void *c) {
        int dbg_mode = 0;

        if (rpc->scan(c, "d", &dbg_mode) < 1) return;

        LOCK_GET(rl_lock);
        if (dbg_mode) {
                if (!rl_dbg_str->s) {
                        rl_dbg_str->len = (MAX_PIPES * 5 * sizeof(char));
                        rl_dbg_str->s = (char *)shm_malloc(rl_dbg_str->len);
                        if (!rl_dbg_str->s) {
                                rl_dbg_str->len = 0;
                                LM_ERR("oom: %d\n", rl_dbg_str->len);
                        }
                }
        } else {
                if (rl_dbg_str->s) {
                        shm_free(rl_dbg_str->s);
                        rl_dbg_str->s = NULL;
                        rl_dbg_str->len = 0;
                }
        }
        LOCK_RELEASE(rl_lock);
}

static rpc_export_t rpc_methods[] = {
        {"rl.stats",            rpc_stats,      rpc_stats_doc,          0},
        {"rl.get_pipes",        rpc_get_pipes,  rpc_get_pipes_doc,      0},
        {"rl.set_pipe",         rpc_set_pipe,   rpc_set_pipe_doc,       0},
        {"rl.get_queues",       rpc_get_queues, rpc_get_queues_doc,     0},
        {"rl.set_queue",        rpc_set_queue,  rpc_set_queue_doc,      0},
        {"rl.get_pid",          rpc_get_pid,    rpc_get_pid_doc,        0},
        {"rl.set_pid",          rpc_set_pid,    rpc_set_pid_doc,        0},
        {"rl.push_load",        rpc_push_load,  rpc_push_load_doc,      0},
        {"rl.set_dbg",          rpc_set_dbg,    rpc_set_dbg_doc,        0},
        {0, 0, 0, 0}
};