lighttpd 1.4.x https://www.lighttpd.net/
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#include "first.h"
#include "base.h"
#include "log.h"
#include "buffer.h"
#include "http_header.h"
#include "sock_addr.h"
#include "plugin.h"
#include <stdlib.h>
#include <string.h>
/**
* mod_evasive
*
* we indent to implement all features the mod_evasive from apache has
*
* - limit of connections per IP
* - provide a list of block-listed ip/networks (no access)
* - provide a white-list of ips/network which is not affected by the limit
* (hmm, conditionals might be enough)
* - provide a bandwidth limiter per IP
*
* started by:
* - w1zzard@techpowerup.com
*/
typedef struct {
unsigned short max_conns;
unsigned short silent;
buffer *location;
} plugin_config;
typedef struct {
PLUGIN_DATA;
plugin_config **config_storage;
plugin_config conf;
} plugin_data;
INIT_FUNC(mod_evasive_init) {
plugin_data *p;
p = calloc(1, sizeof(*p));
return p;
}
FREE_FUNC(mod_evasive_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 (NULL == s) continue;
buffer_free(s->location);
free(s);
}
free(p->config_storage);
}
free(p);
return HANDLER_GO_ON;
}
SETDEFAULTS_FUNC(mod_evasive_set_defaults) {
plugin_data *p = p_d;
size_t i = 0;
config_values_t cv[] = {
{ "evasive.max-conns-per-ip", NULL, T_CONFIG_SHORT, T_CONFIG_SCOPE_CONNECTION }, /* 0 */
{ "evasive.silent", NULL, T_CONFIG_BOOLEAN, T_CONFIG_SCOPE_CONNECTION }, /* 1 */
{ "evasive.location", NULL, T_CONFIG_STRING, T_CONFIG_SCOPE_CONNECTION }, /* 2 */
{ NULL, NULL, T_CONFIG_UNSET, T_CONFIG_SCOPE_UNSET }
};
p->config_storage = calloc(srv->config_context->used, sizeof(plugin_config *));
for (i = 0; i < srv->config_context->used; i++) {
data_config const* config = (data_config const*)srv->config_context->data[i];
plugin_config *s;
s = calloc(1, sizeof(plugin_config));
s->max_conns = 0;
s->silent = 0;
s->location = buffer_init();
cv[0].destination = &(s->max_conns);
cv[1].destination = &(s->silent);
cv[2].destination = s->location;
p->config_storage[i] = s;
if (0 != config_insert_values_global(srv, config->value, cv, i == 0 ? T_CONFIG_SCOPE_SERVER : T_CONFIG_SCOPE_CONNECTION)) {
return HANDLER_ERROR;
}
}
return HANDLER_GO_ON;
}
#define PATCH(x) \
p->conf.x = s->x;
static int mod_evasive_patch_connection(server *srv, connection *con, plugin_data *p) {
size_t i, j;
plugin_config *s = p->config_storage[0];
PATCH(max_conns);
PATCH(silent);
PATCH(location);
/* 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("evasive.max-conns-per-ip"))) {
PATCH(max_conns);
} else if (buffer_is_equal_string(du->key, CONST_STR_LEN("evasive.silent"))) {
PATCH(silent);
} else if (buffer_is_equal_string(du->key, CONST_STR_LEN("evasive.location"))) {
PATCH(location);
}
}
}
return 0;
}
#undef PATCH
URIHANDLER_FUNC(mod_evasive_uri_handler) {
plugin_data *p = p_d;
size_t conns_by_ip = 0;
size_t j;
if (buffer_is_empty(con->uri.path)) return HANDLER_GO_ON;
mod_evasive_patch_connection(srv, con, p);
/* no limit set, nothing to block */
if (p->conf.max_conns == 0) return HANDLER_GO_ON;
for (j = 0; j < srv->conns->used; j++) {
connection *c = srv->conns->ptr[j];
/* check if other connections are already actively serving data for the same IP
* we can only ban connections which are already behind the 'read request' state
* */
if (c->state <= CON_STATE_REQUEST_END) continue;
if (!sock_addr_is_addr_eq(&c->dst_addr, &con->dst_addr)) continue;
conns_by_ip++;
if (conns_by_ip > p->conf.max_conns) {
if (!p->conf.silent) {
log_error_write(srv, __FILE__, __LINE__, "bs",
con->dst_addr_buf,
"turned away. Too many connections.");
}
if (!buffer_is_empty(p->conf.location)) {
http_header_response_set(con, HTTP_HEADER_LOCATION, CONST_STR_LEN("Location"), CONST_BUF_LEN(p->conf.location));
con->http_status = 302;
con->file_finished = 1;
} else {
con->http_status = 403;
}
con->mode = DIRECT;
return HANDLER_FINISHED;
}
}
return HANDLER_GO_ON;
}
int mod_evasive_plugin_init(plugin *p);
int mod_evasive_plugin_init(plugin *p) {
p->version = LIGHTTPD_VERSION_ID;
p->name = buffer_init_string("evasive");
p->init = mod_evasive_init;
p->set_defaults = mod_evasive_set_defaults;
p->handle_uri_clean = mod_evasive_uri_handler;
p->cleanup = mod_evasive_free;
p->data = NULL;
return 0;
}