/* $OpenBSD: bss_acpt.c,v 1.31 2023/07/05 21:23:37 beck Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * 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 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND 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.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <sys/socket.h>

#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include <openssl/bio.h>
#include <openssl/buffer.h>
#include <openssl/err.h>

#include "bio_local.h"

#define SOCKET_PROTOCOL IPPROTO_TCP

typedef struct bio_accept_st {
	int state;
	char *param_addr;

	int accept_sock;
	int accept_nbio;

	char *addr;
	int nbio;
	/* If 0, it means normal, if 1, do a connect on bind failure,
	 * and if there is no-one listening, bind with SO_REUSEADDR.
	 * If 2, always use SO_REUSEADDR. */
	int bind_mode;
	BIO *bio_chain;
} BIO_ACCEPT;

static int acpt_write(BIO *h, const char *buf, int num);
static int acpt_read(BIO *h, char *buf, int size);
static int acpt_puts(BIO *h, const char *str);
static long acpt_ctrl(BIO *h, int cmd, long arg1, void *arg2);
static int acpt_new(BIO *h);
static int acpt_free(BIO *data);
static int acpt_state(BIO *b, BIO_ACCEPT *c);
static void acpt_close_socket(BIO *data);
static BIO_ACCEPT *BIO_ACCEPT_new(void );
static void BIO_ACCEPT_free(BIO_ACCEPT *a);

#define ACPT_S_BEFORE			1
#define ACPT_S_GET_ACCEPT_SOCKET	2
#define ACPT_S_OK			3

static const BIO_METHOD methods_acceptp = {
	.type = BIO_TYPE_ACCEPT,
	.name = "socket accept",
	.bwrite = acpt_write,
	.bread = acpt_read,
	.bputs = acpt_puts,
	.ctrl = acpt_ctrl,
	.create = acpt_new,
	.destroy = acpt_free
};

const BIO_METHOD *
BIO_s_accept(void)
{
	return (&methods_acceptp);
}
LCRYPTO_ALIAS(BIO_s_accept);

static int
acpt_new(BIO *bi)
{
	BIO_ACCEPT *ba;

	bi->init = 0;
	bi->num = -1;
	bi->flags = 0;
	if ((ba = BIO_ACCEPT_new()) == NULL)
		return (0);
	bi->ptr = (char *)ba;
	ba->state = ACPT_S_BEFORE;
	bi->shutdown = 1;
	return (1);
}

static BIO_ACCEPT *
BIO_ACCEPT_new(void)
{
	BIO_ACCEPT *ret;

	if ((ret = calloc(1, sizeof(BIO_ACCEPT))) == NULL)
		return (NULL);
	ret->accept_sock = -1;
	ret->bind_mode = BIO_BIND_NORMAL;
	return (ret);
}

static void
BIO_ACCEPT_free(BIO_ACCEPT *a)
{
	if (a == NULL)
		return;

	free(a->param_addr);
	free(a->addr);
	BIO_free(a->bio_chain);
	free(a);
}

static void
acpt_close_socket(BIO *bio)
{
	BIO_ACCEPT *c;

	c = (BIO_ACCEPT *)bio->ptr;
	if (c->accept_sock != -1) {
		shutdown(c->accept_sock, SHUT_RDWR);
		close(c->accept_sock);
		c->accept_sock = -1;
		bio->num = -1;
	}
}

static int
acpt_free(BIO *a)
{
	BIO_ACCEPT *data;

	if (a == NULL)
		return (0);
	data = (BIO_ACCEPT *)a->ptr;

	if (a->shutdown) {
		acpt_close_socket(a);
		BIO_ACCEPT_free(data);
		a->ptr = NULL;
		a->flags = 0;
		a->init = 0;
	}
	return (1);
}

static int
acpt_state(BIO *b, BIO_ACCEPT *c)
{
	BIO *bio = NULL, *dbio;
	int s = -1;
	int i;

again:
	switch (c->state) {
	case ACPT_S_BEFORE:
		if (c->param_addr == NULL) {
			BIOerror(BIO_R_NO_ACCEPT_PORT_SPECIFIED);
			return (-1);
		}
		s = BIO_get_accept_socket(c->param_addr, c->bind_mode);
		if (s == -1)
			return (-1);

		if (c->accept_nbio) {
			if (!BIO_socket_nbio(s, 1)) {
				close(s);
				BIOerror(BIO_R_ERROR_SETTING_NBIO_ON_ACCEPT_SOCKET);
				return (-1);
			}
		}
		c->accept_sock = s;
		b->num = s;
		c->state = ACPT_S_GET_ACCEPT_SOCKET;
		return (1);
		/* break; */
	case ACPT_S_GET_ACCEPT_SOCKET:
		if (b->next_bio != NULL) {
			c->state = ACPT_S_OK;
			goto again;
		}
		BIO_clear_retry_flags(b);
		b->retry_reason = 0;
		i = BIO_accept(c->accept_sock, &(c->addr));

		/* -2 return means we should retry */
		if (i == -2) {
			BIO_set_retry_special(b);
			b->retry_reason = BIO_RR_ACCEPT;
			return -1;
		}

		if (i < 0)
			return (i);

		bio = BIO_new_socket(i, BIO_CLOSE);
		if (bio == NULL)
			goto err;

		BIO_set_callback(bio, BIO_get_callback(b));
		BIO_set_callback_arg(bio, BIO_get_callback_arg(b));

		if (c->nbio) {
			if (!BIO_socket_nbio(i, 1)) {
				BIOerror(BIO_R_ERROR_SETTING_NBIO_ON_ACCEPTED_SOCKET);
				goto err;
			}
		}

		/* If the accept BIO has an bio_chain, we dup it and
		 * put the new socket at the end. */
		if (c->bio_chain != NULL) {
			if ((dbio = BIO_dup_chain(c->bio_chain)) == NULL)
				goto err;
			if (!BIO_push(dbio, bio)) goto err;
				bio = dbio;
		}
		if (BIO_push(b, bio)
			== NULL) goto err;

		c->state = ACPT_S_OK;
		return (1);

err:
		if (bio != NULL)
			BIO_free(bio);
		return (0);
		/* break; */
	case ACPT_S_OK:
		if (b->next_bio == NULL) {
			c->state = ACPT_S_GET_ACCEPT_SOCKET;
			goto again;
		}
		return (1);
		/* break; */
	default:
		return (0);
		/* break; */
	}
}

static int
acpt_read(BIO *b, char *out, int outl)
{
	int ret = 0;
	BIO_ACCEPT *data;

	BIO_clear_retry_flags(b);
	data = (BIO_ACCEPT *)b->ptr;

	while (b->next_bio == NULL) {
		ret = acpt_state(b, data);
		if (ret <= 0)
			return (ret);
	}

	ret = BIO_read(b->next_bio, out, outl);
	BIO_copy_next_retry(b);
	return (ret);
}

static int
acpt_write(BIO *b, const char *in, int inl)
{
	int ret;
	BIO_ACCEPT *data;

	BIO_clear_retry_flags(b);
	data = (BIO_ACCEPT *)b->ptr;

	while (b->next_bio == NULL) {
		ret = acpt_state(b, data);
		if (ret <= 0)
			return (ret);
	}

	ret = BIO_write(b->next_bio, in, inl);
	BIO_copy_next_retry(b);
	return (ret);
}

static long
acpt_ctrl(BIO *b, int cmd, long num, void *ptr)
{
	int *ip;
	long ret = 1;
	BIO_ACCEPT *data;
	char **pp;

	data = (BIO_ACCEPT *)b->ptr;

	switch (cmd) {
	case BIO_CTRL_RESET:
		ret = 0;
		data->state = ACPT_S_BEFORE;
		acpt_close_socket(b);
		b->flags = 0;
		break;
	case BIO_C_DO_STATE_MACHINE:
		/* use this one to start the connection */
		ret = (long)acpt_state(b, data);
		break;
	case BIO_C_SET_ACCEPT:
		if (ptr != NULL) {
			if (num == 0) {
				b->init = 1;
				free(data->param_addr);
				data->param_addr = strdup(ptr);
			} else if (num == 1) {
				data->accept_nbio = (ptr != NULL);
			} else if (num == 2) {
				BIO_free(data->bio_chain);
				data->bio_chain = (BIO *)ptr;
			}
		}
		break;
	case BIO_C_SET_NBIO:
		data->nbio = (int)num;
		break;
	case BIO_C_SET_FD:
		b->init = 1;
		b->num= *((int *)ptr);
		data->accept_sock = b->num;
		data->state = ACPT_S_GET_ACCEPT_SOCKET;
		b->shutdown = (int)num;
		b->init = 1;
		break;
	case BIO_C_GET_FD:
		if (b->init) {
			ip = (int *)ptr;
			if (ip != NULL)
				*ip = data->accept_sock;
			ret = data->accept_sock;
		} else
			ret = -1;
		break;
	case BIO_C_GET_ACCEPT:
		if (b->init) {
			if (ptr != NULL) {
				pp = (char **)ptr;
				*pp = data->param_addr;
			} else
				ret = -1;
		} else
			ret = -1;
		break;
	case BIO_CTRL_GET_CLOSE:
		ret = b->shutdown;
		break;
	case BIO_CTRL_SET_CLOSE:
		b->shutdown = (int)num;
		break;
	case BIO_CTRL_PENDING:
	case BIO_CTRL_WPENDING:
		ret = 0;
		break;
	case BIO_CTRL_FLUSH:
		break;
	case BIO_C_SET_BIND_MODE:
		data->bind_mode = (int)num;
		break;
	case BIO_C_GET_BIND_MODE:
		ret = (long)data->bind_mode;
		break;
	case BIO_CTRL_DUP:
/*		dbio=(BIO *)ptr;
		if (data->param_port) EAY EAY
			BIO_set_port(dbio,data->param_port);
		if (data->param_hostname)
			BIO_set_hostname(dbio,data->param_hostname);
		BIO_set_nbio(dbio,data->nbio);
*/
		break;

	default:
		ret = 0;
		break;
	}
	return (ret);
}

static int
acpt_puts(BIO *bp, const char *str)
{
	int n, ret;

	n = strlen(str);
	ret = acpt_write(bp, str, n);
	return (ret);
}

BIO *
BIO_new_accept(const char *str)
{
	BIO *ret;

	ret = BIO_new(BIO_s_accept());
	if (ret == NULL)
		return (NULL);
	if (BIO_set_accept_port(ret, str))
		return (ret);
	else {
		BIO_free(ret);
		return (NULL);
	}
}
LCRYPTO_ALIAS(BIO_new_accept);