#include "mod_rangelimit.h"

// Module version: 1.0

#ifdef APACHE2

module AP_MODULE_DECLARE_DATA rangelimit_module;

#else

module MODULE_VAR_EXPORT rangelimit_module;

#endif

typedef struct {

int max_ranges;

int max_overlaps;

} ranges_server_conf;

#ifdef APACHE2

static void *create_rangelim_config(apr_pool_t *p, server_rec *s) {

ranges_server_conf *cfg = (ranges_server_conf *) apr_pcalloc(p, sizeof(ranges_server_conf));

#else

static void *create_rangelim_config(pool *p, server_rec *s) {

ranges_server_conf *cfg = (ranges_server_conf *) ap_pcalloc(p, sizeof(ranges_server_conf));

#endif

cfg->max_ranges = 20;

cfg->max_overlaps = 5;

return cfg;

}

static int check_range(int *arr, int *val) {

int i = 0;

for (i=0;i<=16;i++) {

if (*arr == 0)

return 0;

if (*arr == *val)

return i;

arr++;

}

return -1;

}

static int range_handler(request_rec *r) {

#ifdef APACHE2

const char *range_header = apr_table_get(r->headers_in, "Range");

#else

const char *range_header = ap_table_get(r->headers_in, "Range");

#endif

ranges_server_conf *cfg = ap_get_module_config(r->server->module_config, &rangelimit_module);

int range_num = 0; // counter of the number of checked ranges

int range_overlaps = 0; // counter of the number of overlapping ranges

char *ranges = NULL; // pointer to keep the ranges location

int start = -1, end = -1; // start and end of a single range

int n = 0; // number of characters collected by sscanf()

int start_count = 0; // counter for the new unique starts

int end_count = 0; // counter for the new unique ends

int begins[60];

int ends[60];

if (!range_header || strncasecmp(range_header, "bytes=", 6) || r->status != HTTP_OK ) {

if (r->server->loglevel == APLOG_DEBUG)

#ifdef APACHE2

ap_log_rerror(APLOG_MARK, APLOG_NOTICE, 0, r, "mod_rangelimit: no range found" );

#else

ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, r, "mod_rangelimit: no range found" );

#endif

return OK;

}

// if (r->server->loglevel == APLOG_DEBUG)

//#ifdef APACHE2

// ap_log_rerror(APLOG_MARK, APLOG_NOTICE, 0, r, "mod_rangelimit: Range header: %s", range_header);

//#else

// ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, r, "mod_rangelimit: Range header: %s", range_header);

//#endif

#ifdef APACHE2

if (!ap_strchr_c(range_header, ',')) {

#else

if (!strchr(range_header, ',')) {

#endif

if (r->server->loglevel == APLOG_DEBUG)

#ifdef APACHE2

ap_log_rerror(APLOG_MARK, APLOG_NOTICE, 0, r, "mod_rangelimit: single range, nothing to do here");

#else

ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, r, "mod_rangelimit: single range, nothing to do here");

#endif

return OK;

}

// multiple ranges

#ifdef APACHE2

ranges = ap_strchr_c(range_header, '=');

#else

ranges = strchr(range_header, '=');

#endif

ranges++; // move the pointer to the begining of the first range

// start walking over the ranges

while ( sscanf(ranges, "%11d-%11d%n", &start, &end, &n) >= 1 ) {

if (start < 0) {

#ifdef APACHE2

ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,

"mod_rangelimit: requested range(%d-%d) not satisfiable", start, end);

#else

ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_ERR, r,

"mod_rangelimit: requested range(%d-%d) not satisfiable", start, end);

#endif

return HTTP_RANGE_NOT_SATISFIABLE;

}

if (end >= 0 && end < start) {

#ifdef APACHE2

ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,

"mod_rangelimit: requested range(%d-%d) not satisfiable", start, end);

#else

ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_ERR, r,

"mod_rangelimit: requested range(%d-%d) not satisfiable", start, end);

#endif

return HTTP_RANGE_NOT_SATISFIABLE;

}

// code for handling overlaps

if (check_range(begins, &start) > 0) {

range_overlaps++;

} else {

begins[start_count] = start;

start_count++;

}

if (check_range(ends, &end) > 0) {

range_overlaps++;

} else {

ends[end_count] = end;

end_count++;

}

// end of the overlaps code

range_num++; // increase the number of found ranges

if (r->server->loglevel == APLOG_DEBUG)

#ifdef APACHE2

ap_log_rerror(APLOG_MARK, APLOG_NOTICE, 0, r,

"mod_rangelimit: range_num: %d overpalpping: %d start: %d end: %d n: %d",

range_num, range_overlaps, start, end, n);

#else

ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, r,

"mod_rangelimit: range_num: %d overpalpping: %d start: %d end: %d n: %d",

range_num, range_overlaps, start, end, n);

#endif

if (range_num > cfg->max_ranges) {

#ifdef APACHE2

ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,

"mod_rangelimit: too many ranges - %d", range_num);

#else

ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_ERR, r,

"mod_rangelimit: too many ranges - %d", range_num);

#endif

return HTTP_RANGE_NOT_SATISFIABLE;

}

if (range_overlaps > cfg->max_overlaps) {

#ifdef APACHE2

ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,

"mod_rangelimit: too many overlapping ranges - %d", range_overlaps);

#else

ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_ERR, r,

"mod_rangelimit: too many overlapping ranges - %d", range_overlaps);

#endif

return HTTP_RANGE_NOT_SATISFIABLE;

}

if (end == -1) {

// since n is not set when end is not read

// find the end of this range using strchr

#ifdef APACHE2

ranges = ap_strchr_c(ranges, '-') + 1;

#else

ranges = strchr(ranges, '-') + 1;

#endif

} else {

ranges += n; // advance the pointer by the number of characters read

}

if ( *ranges != ',' ) {

break; // didn't find an expected delimiter, done?

}

++ranges; // skip the delimiter

start = end = -1; // clear the start and end points

n = 0; // clear the number of found chars

}

return OK;

}

static const char *set_max_ranges(cmd_parms *cmd, void *mconfig, const char *arg) {

ranges_server_conf *cfg = ap_get_module_config(cmd->server->module_config, &rangelimit_module);

cfg->max_ranges = atoi(arg);

return NULL;

}

static const char *set_max_overlaps(cmd_parms *cmd, void *mconfig, const char *arg) {

ranges_server_conf *cfg = ap_get_module_config(cmd->server->module_config, &rangelimit_module);

cfg->max_overlaps = atoi(arg);

return NULL;

}

static const command_rec rangelim_cmds[] = {

#ifdef APACHE2

AP_INIT_TAKE1("MaxRanges", set_max_ranges, NULL, RSRC_CONF,

"Define the maximum number of allowed range definitions. Default 20"),

AP_INIT_TAKE1("MaxOverlappingRanges", set_max_overlaps, NULL, RSRC_CONF,

"Define the maximum number of allowed ranges that overlap each other. Default 5"),

#else

{ "MaxRanges", set_max_ranges, NULL, RSRC_CONF, TAKE1,

"Define the maximum number of allowed range definitions. Default 20" },

{ "MaxOverlappingRanges", set_max_overlaps, NULL, RSRC_CONF, TAKE1,

"Define the maximum number of allowed ranges that overlap each other. Default 5" },

#endif

{NULL}

};

#ifdef APACHE2

static void register_hooks(apr_pool_t *p) {

static const char * const aszPost[] = { "mod_setenvif.c", NULL };

ap_hook_header_parser(range_handler, NULL, aszPost, APR_HOOK_MIDDLE);

}

module AP_MODULE_DECLARE_DATA rangelimit_module = {

STANDARD20_MODULE_STUFF,

NULL, /* per-directory config creator */

NULL, /* dir config merger */

create_rangelim_config, /* server config creator */

NULL, /* server config merger */

rangelim_cmds, /* command table */

register_hooks, /* set up other request processing hooks */

};

#else

module MODULE_VAR_EXPORT rangelimit_module = {

STANDARD_MODULE_STUFF,

NULL, /* module initializer */

NULL, /* per-directory config creator */

NULL, /* dir config merger */

create_rangelim_config, /* server config creator */

NULL, /* server config merger */

rangelim_cmds, /* command table */

NULL, /* [9] list of handlers */

NULL, /* [2] filename-to-URI translation */

NULL, /* [5] check/validate user_id */

NULL, /* [6] check user_id is valid *here* */

NULL, /* [4] check access by host address */

NULL, /* [7] MIME type checker/setter */

NULL, /* [8] fixups */

NULL, /* [10] logger */

#if MODULE_MAGIC_NUMBER >= 19970103

range_handler, /* [3] header parser */

#endif

#if MODULE_MAGIC_NUMBER >= 19970719

NULL, /* process initializer */

#endif

#if MODULE_MAGIC_NUMBER >= 19970728

NULL, /* process exit/cleanup */

#endif

#if MODULE_MAGIC_NUMBER >= 19970902

NULL /* [1] post read_request handling */

#endif

};

#endif // APACHE2