Docs/TrafficShaping: mod_speed.c

#include <ctype.h>
#include <stdlib.h>
#include <string.h>

#include "base.h"
#include "log.h"
#include "buffer.h"

#include "plugin.h"
#include <unistd.h>

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

/**
 * small lighttpd-plugin for selective speed
 *
 * Bjoern Kalkbrenner <terminar@cyberphoria.org> [20070204]
 *
 * Adds: X-LIGHTTPD-KBytes-per-second header, you now can use e.g.
 * <?php
 * header("X-LIGHTTPD-KBytes-per-second: 20");
 * header("X-Sendfile: /path/to/file");
 * ?>
 * to set the max speed for the download/current connection. This can be also used with reproxy.
 * Options:
 * # use this on the frontend to just copy the header from the response to the request header (forward it to the backend)
 * speed.just-copy-header = "enable"
 * # use this on the backend to fetch the speed from the request. This is not useful on the frontend, i think :)
 * speed.use-request = "enable"
 * 
 */
        
        

/* plugin config for all request/connections */

typedef struct {
        unsigned short just_copy_header;
        unsigned short use_request;
} plugin_config;

typedef struct {
        PLUGIN_DATA;

        buffer *tmp_buf;

        plugin_config **config_storage;

        plugin_config conf;
} plugin_data;

/* init the plugin data */
INIT_FUNC(mod_speed_init) {
        plugin_data *p;
        
        UNUSED(srv);

        p = calloc(1, sizeof(*p));

        return p;
}

/* detroy the plugin data */
FREE_FUNC(mod_speed_free) {
        plugin_data *p = p_d;

        UNUSED(srv);

        if (!p) return HANDLER_GO_ON;

        if (p->config_storage) {
                size_t i;
                
                for (i = 0; i < srv->config_context->used; i++) {
                        plugin_config *s = p->config_storage[i];

                        if (!s) continue;

                        free(s);
                }
                free(p->config_storage);
        }

        free(p);

        return HANDLER_GO_ON;
}

/* handle plugin config and check values */
SETDEFAULTS_FUNC(mod_speed_set_defaults) {
        plugin_data *p = p_d;
        size_t i = 0;

        config_values_t cv[] = {
                { "speed.just-copy-header", NULL, T_CONFIG_BOOLEAN, T_CONFIG_SCOPE_CONNECTION },       /* 0 */
                { "speed.use-request", NULL, T_CONFIG_BOOLEAN, T_CONFIG_SCOPE_CONNECTION },       /* 1 */
                { NULL,                         NULL, T_CONFIG_UNSET, T_CONFIG_SCOPE_UNSET }
        };

        if (!p) return HANDLER_ERROR;

        p->config_storage = calloc(1, srv->config_context->used * sizeof(specific_config *));

        for (i = 0; i < srv->config_context->used; i++) {
                plugin_config *s;

                s = calloc(1, sizeof(plugin_config));
                s->just_copy_header = 0;
                s->use_request = 0;

                cv[0].destination = &(s->just_copy_header);
                cv[1].destination = &(s->use_request);
                
                p->config_storage[i] = s;

                if (0 != config_insert_values_global(srv, ((data_config *)srv->config_context->data[i])->value, cv)) {
                    TRACE("%s","error inserting values config");
                        return HANDLER_ERROR;
                }

                                                
        }


        return HANDLER_GO_ON;
}

static int mod_speed_patch_connection(server *srv, connection *con, plugin_data *p) {
        size_t i, j;
        plugin_config *s = p->config_storage[0];

        PATCH_OPTION(just_copy_header);
        PATCH_OPTION(use_request);

        /* skip the first, the global context */
        for (i = 1; i < srv->config_context->used; i++) {
        
                data_config *dc = (data_config *)srv->config_context->data[i];
                s = p->config_storage[i];

                /* condition didn't match */
                if (!config_check_cond(srv, con, dc)) continue;

                /* merge config */
                for (j = 0; j < dc->value->used; j++) {
                        data_unset *du = dc->value->data[j];

                        if (buffer_is_equal_string(du->key, CONST_STR_LEN("speed.just-copy-header"))) {
                        TRACE("%s","copy header set");
                                PATCH_OPTION(just_copy_header);
                        }
                        
                        if (buffer_is_equal_string(du->key, CONST_STR_LEN("speed.use-request"))) {
                        TRACE("%s","use request header set");
                                PATCH_OPTION(use_request);
                        }
                        
                }
        }

        return 0;
}

URIHANDLER_FUNC(mod_speed_send_request_content) {
        plugin_data *p = p_d;
        buffer *b=NULL;
        data_string *ds = NULL;
        data_string *ds_request = NULL;
        int found=0;

        mod_speed_patch_connection(srv, con, p);

        if (NULL != (ds = (data_string *)array_get_element(con->response.headers, CONST_STR_LEN("X-LIGHTTPD-KBytes-per-second")))) {
            if (p->conf.just_copy_header > 0) {

                if (NULL == (ds_request = (data_string *)array_get_element(con->request.headers, CONST_STR_LEN("X-LIGHTTPD-KBytes-per-second")))) {
                
                    if (NULL == (ds_request = (data_string *)array_get_unused_element(con->request.headers, TYPE_STRING))) {
                        ds_request = data_string_init();
                    }
                    
                } else {
                    found=1;
                } 
                                
                buffer_copy_string(ds_request->key, "X-LIGHTTPD-KBytes-per-second");
                buffer_copy_string(ds_request->value, ds->value->ptr);
                if (!found)
                {
                    array_insert_unique(con->request.headers, (data_unset *)ds_request);
                }
                
            } else
            {
                con->conf.kbytes_per_second = atol(ds->value->ptr);
                TRACE("===> Found my header for speed in send_request_content: %s",ds->value->ptr);
            }
            
        }

        /* not found */
        return HANDLER_GO_ON;
}

URIHANDLER_FUNC(mod_speed_start_backend) {
        plugin_data *p = p_d;
        buffer *b=NULL;
        data_string *ds = NULL;
        data_string *ds_request = NULL;

        mod_speed_patch_connection(srv, con, p);

        if (p->conf.use_request > 0)
        {
                if (NULL != (ds = (data_string *)array_get_element(con->request.headers, CONST_STR_LEN("X-LIGHTTPD-KBytes-per-second")))) {
        
                    con->conf.kbytes_per_second = atol(ds->value->ptr);
                }
        }
        
        /* not found */
        return HANDLER_GO_ON;
}


/* this function is called at dlopen() time and inits the callbacks */

int mod_speed_plugin_init(plugin *p) {
        p->version     = LIGHTTPD_VERSION_ID;
        p->name        = buffer_init_string("speed");

        p->init        = mod_speed_init;
        p->set_defaults  = mod_speed_set_defaults;
        p->cleanup     = mod_speed_free;

        p->handle_start_backend = mod_speed_start_backend;
        p->handle_send_request_content = mod_speed_send_request_content;

        p->data        = NULL;

        return 0;
}