/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2000-2002 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
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 * 4. The names "Apache" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
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 * 5. Products derived from this software may not be called "Apache",
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 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * Portions of this software are based upon public domain software
 * originally written at the National Center for Supercomputing Applications,
 * University of Illinois, Urbana-Champaign.
 */

/*
 * mod_sockopts: control SO_RCVBUF and TCP_DEFER_ACCEPT
 *
 * v1.0
 * 
 * author: dean gaudet <dean@arctic.org>
 */

// dunno why ap_check_cmd_context is private...
#define CORE_PRIVATE
#include "httpd.h"
#include "http_config.h"
#include "http_log.h"
#include "http_request.h"
#include "http_conf_globals.h"

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>

typedef struct {
	int receive_buffer_size;
	int tcp_defer_accept;
	unsigned receive_buffer_size_set : 1;
	unsigned tcp_defer_accept_set : 1;
} sockopts_config;

module MODULE_VAR_EXPORT sockopts_module;


static const char *set_receive_buffer_size(cmd_parms *cmd, void *dummy, char *arg)
{
	sockopts_config *config = ap_get_module_config(cmd->server->module_config, &sockopts_module);
	int s = atoi(arg);
	const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);

	if (err != NULL) {
		return err;
	}

	if (s < 512 && s != 0) {
		return "ReceiveBufferSize must be >= 512 bytes, or 0 for system default.";
	}
	config->receive_buffer_size = s;
	config->receive_buffer_size_set = 1;

	return NULL;
}


static const char *set_tcp_defer_accept(cmd_parms *cmd, void *dummy, char *arg)
{
#ifdef TCP_DEFER_ACCEPT
	sockopts_config *config = ap_get_module_config(cmd->server->module_config, &sockopts_module);
	int s = atoi(arg);
	const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);

	if (err != NULL) {
		return err;
	}

	config->tcp_defer_accept = s;
	config->tcp_defer_accept_set = 1;
	return NULL;
#else
	return "TCP_DEFER_ACCEPT not supported on your platform";
#endif
}


static void *sockopts_create_config(pool *p, server_rec *s)
{
	return ap_pcalloc(p, sizeof(sockopts_config));
}


static void *sockopts_merge_config(pool *p, void *parentv, void *childv)
{
	sockopts_config *parent = (sockopts_config *) parentv;
	sockopts_config *child = (sockopts_config *) childv;
	sockopts_config *config;

	config = (sockopts_config *)ap_palloc(p, sizeof(*config));
	*config = *parent;
	if (child->receive_buffer_size_set) {
		config->receive_buffer_size_set = 1;
		config->receive_buffer_size = child->receive_buffer_size;
	}
	if (child->tcp_defer_accept_set) {
		config->tcp_defer_accept_set = 1;
		config->tcp_defer_accept = child->tcp_defer_accept;
	}
	return config;
}


static void sockopts_init(server_rec *s, pool *p)
{
	sockopts_config *config = ap_get_module_config(s->module_config,
			&sockopts_module);
	listen_rec *lr;
	int val;

	lr = ap_listeners;
	if (lr == NULL) {
		return;
	}
	do {
		// apache initialization sequence is such a mess... we end up
		// in here once before any listeners have been allocated... so
		// we don't want to try to setsockopt then.
		if (lr->fd != -1) {
			if (config->receive_buffer_size_set) {
				val = config->receive_buffer_size;
				if (setsockopt(lr->fd, SOL_SOCKET, SO_RCVBUF, (char *)&val, sizeof(int)) < 0) {
					ap_log_error(APLOG_MARK, APLOG_WARNING, s,
							"failed to setsockopt(SOL_SOCKET, SO_RCVBUF)");
				}
			}
#ifdef TCP_DEFER_ACCEPT
			if (config->tcp_defer_accept_set) {
				val = config->tcp_defer_accept;
				if (setsockopt(lr->fd, IPPROTO_TCP, TCP_DEFER_ACCEPT, (char *)&val, sizeof(int)) < 0) {
					ap_log_error(APLOG_MARK, APLOG_WARNING, s,
							"failed to setsockopt(IPPROTO_TCP, TCP_DEFER_ACCEPT)");
				}
			}
#endif
		}
		lr = lr->next;
	} while (lr && lr != ap_listeners);
}


static const command_rec sockopts_cmds[] =
{
	{ "ReceiveBufferSize", set_receive_buffer_size, NULL, RSRC_CONF, TAKE1,
		"Receive buffer size in bytes"
	},
	{ "TCPDeferAccept", set_tcp_defer_accept, NULL, RSRC_CONF, TAKE1,
		"TCP_DEFER_ACCEPT setting in seconds (see tcp(7))"
	},
	{NULL}
};


module MODULE_VAR_EXPORT sockopts_module =
{
    STANDARD_MODULE_STUFF,
    sockopts_init,		/* module initializer */
    NULL,			/* per-directory config creator */
    NULL,			/* dir config merger */
    sockopts_create_config,	/* server config creator */
    sockopts_merge_config,	/* server config merger */
    sockopts_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
    ,NULL			/* [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
};