/*
 * libwebsockets - small server side websockets and web server implementation
 *
 * Copyright (C) 2010-2018 Andy Green <andy@warmcat.com>
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation:
 *  version 2.1 of the License.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 *  MA  02110-1301  USA
 */

#include "core/private.h"


static int
lws_get_idlest_tsi(struct lws_context *context)
{
	unsigned int lowest = ~0;
	int n = 0, hit = -1;

	for (; n < context->count_threads; n++) {
		if ((unsigned int)context->pt[n].fds_count !=
		    context->fd_limit_per_thread - 1 &&
		    (unsigned int)context->pt[n].fds_count < lowest) {
			lowest = context->pt[n].fds_count;
			hit = n;
		}
	}

	return hit;
}

struct lws *
lws_create_new_server_wsi(struct lws_vhost *vhost, int fixed_tsi)
{
	struct lws *new_wsi;
	int n = fixed_tsi;

	if (n < 0)
		n = lws_get_idlest_tsi(vhost->context);

	if (n < 0) {
		lwsl_err("no space for new conn\n");
		return NULL;
	}

	new_wsi = lws_zalloc(sizeof(struct lws), "new server wsi");
	if (new_wsi == NULL) {
		lwsl_err("Out of memory for new connection\n");
		return NULL;
	}

	new_wsi->tsi = n;
	lwsl_debug("new wsi %p joining vhost %s, tsi %d\n", new_wsi,
		   vhost->name, new_wsi->tsi);

	lws_vhost_bind_wsi(vhost, new_wsi);
	new_wsi->context = vhost->context;
	new_wsi->pending_timeout = NO_PENDING_TIMEOUT;
	new_wsi->rxflow_change_to = LWS_RXFLOW_ALLOW;

	/* initialize the instance struct */

	lwsi_set_state(new_wsi, LRS_UNCONNECTED);
	new_wsi->hdr_parsing_completed = 0;

#ifdef LWS_WITH_TLS
	new_wsi->tls.use_ssl = LWS_SSL_ENABLED(vhost);
#endif

	/*
	 * these can only be set once the protocol is known
	 * we set an un-established connection's protocol pointer
	 * to the start of the supported list, so it can look
	 * for matching ones during the handshake
	 */
	new_wsi->protocol = vhost->protocols;
	new_wsi->user_space = NULL;
	new_wsi->desc.sockfd = LWS_SOCK_INVALID;
	new_wsi->position_in_fds_table = LWS_NO_FDS_POS;

	vhost->context->count_wsi_allocated++;

	/*
	 * outermost create notification for wsi
	 * no user_space because no protocol selection
	 */
	vhost->protocols[0].callback(new_wsi, LWS_CALLBACK_WSI_CREATE, NULL,
				     NULL, 0);

	return new_wsi;
}


/* if not a socket, it's a raw, non-ssl file descriptor */

LWS_VISIBLE struct lws *
lws_adopt_descriptor_vhost(struct lws_vhost *vh, lws_adoption_type type,
			   lws_sock_file_fd_type fd, const char *vh_prot_name,
			   struct lws *parent)
{
	struct lws_context *context = vh->context;
	struct lws *new_wsi;
	struct lws_context_per_thread *pt;
	int n;

#if defined(LWS_WITH_PEER_LIMITS)
	struct lws_peer *peer = NULL;

	if (type & LWS_ADOPT_SOCKET) {
		peer = lws_get_or_create_peer(vh, fd.sockfd);

		if (peer && context->ip_limit_wsi &&
		    peer->count_wsi >= context->ip_limit_wsi) {
			lwsl_notice("Peer reached wsi limit %d\n",
					context->ip_limit_wsi);
			lws_stats_atomic_bump(context, &context->pt[0],
					      LWSSTATS_C_PEER_LIMIT_WSI_DENIED,
					      1);
			return NULL;
		}
	}
#endif

	n = -1;
	if (parent)
		n = parent->tsi;
	new_wsi = lws_create_new_server_wsi(vh, n);
	if (!new_wsi) {
		if (type & LWS_ADOPT_SOCKET)
			compatible_close(fd.sockfd);
		return NULL;
	}
#if defined(LWS_WITH_PEER_LIMITS)
	if (peer)
		lws_peer_add_wsi(context, peer, new_wsi);
#endif
	pt = &context->pt[(int)new_wsi->tsi];
	lws_stats_atomic_bump(context, pt, LWSSTATS_C_CONNECTIONS, 1);

	if (parent) {
		new_wsi->parent = parent;
		new_wsi->sibling_list = parent->child_list;
		parent->child_list = new_wsi;
	}

	new_wsi->desc = fd;

	if (vh_prot_name) {
		new_wsi->protocol = lws_vhost_name_to_protocol(new_wsi->vhost,
							       vh_prot_name);
		if (!new_wsi->protocol) {
			lwsl_err("Protocol %s not enabled on vhost %s\n",
				 vh_prot_name, new_wsi->vhost->name);
			goto bail;
		}
		if (lws_ensure_user_space(new_wsi)) {
		       lwsl_notice("OOM trying to get user_space\n");
			goto bail;
		}
	}

	if (!LWS_SSL_ENABLED(new_wsi->vhost) || !(type & LWS_ADOPT_SOCKET))
		type &= ~LWS_ADOPT_ALLOW_SSL;

	if (lws_role_call_adoption_bind(new_wsi, type, vh_prot_name)) {
		lwsl_err("Unable to find a role that can adopt descriptor\n");
		goto bail;
	}

	/*
	 * A new connection was accepted. Give the user a chance to
	 * set properties of the newly created wsi. There's no protocol
	 * selected yet so we issue this to the vhosts's default protocol,
	 * itself by default protocols[0]
	 */
	n = LWS_CALLBACK_SERVER_NEW_CLIENT_INSTANTIATED;
	if (!(type & LWS_ADOPT_HTTP)) {
		if (!(type & LWS_ADOPT_SOCKET))
			n = LWS_CALLBACK_RAW_ADOPT_FILE;
		else
			n = LWS_CALLBACK_RAW_ADOPT;
	}

	lwsl_debug("new wsi wsistate 0x%x\n", new_wsi->wsistate);

	if (context->event_loop_ops->accept)
		if (context->event_loop_ops->accept(new_wsi))
			goto fail;

	if (!(type & LWS_ADOPT_ALLOW_SSL)) {
		lws_pt_lock(pt, __func__);
		if (__insert_wsi_socket_into_fds(context, new_wsi)) {
			lws_pt_unlock(pt);
			lwsl_err("%s: fail inserting socket\n", __func__);
			goto fail;
		}
		lws_pt_unlock(pt);
	} else
		if (lws_server_socket_service_ssl(new_wsi, fd.sockfd)) {
			lwsl_info("%s: fail ssl negotiation\n", __func__);
			goto fail;
		}

	/*
	 *  by deferring callback to this point, after insertion to fds,
	 * lws_callback_on_writable() can work from the callback
	 */
	if ((new_wsi->protocol->callback)(new_wsi, n, new_wsi->user_space,
					  NULL, 0))
		goto fail;

	/* role may need to do something after all adoption completed */

	lws_role_call_adoption_bind(new_wsi, type | _LWS_ADOPT_FINISH,
				    vh_prot_name);

	lws_cancel_service_pt(new_wsi);

	return new_wsi;

fail:
	if (type & LWS_ADOPT_SOCKET)
		lws_close_free_wsi(new_wsi, LWS_CLOSE_STATUS_NOSTATUS,
				   "adopt skt fail");

	return NULL;

bail:
       lwsl_notice("%s: exiting on bail\n", __func__);
	if (parent)
		parent->child_list = new_wsi->sibling_list;
	if (new_wsi->user_space)
		lws_free(new_wsi->user_space);

	vh->context->count_wsi_allocated--;

	lws_vhost_unbind_wsi(new_wsi);
	lws_free(new_wsi);

	compatible_close(fd.sockfd);

	return NULL;
}

LWS_VISIBLE struct lws *
lws_adopt_socket_vhost(struct lws_vhost *vh, lws_sockfd_type accept_fd)
{
	lws_sock_file_fd_type fd;

	fd.sockfd = accept_fd;
	return lws_adopt_descriptor_vhost(vh, LWS_ADOPT_SOCKET |
			LWS_ADOPT_HTTP | LWS_ADOPT_ALLOW_SSL, fd, NULL, NULL);
}

LWS_VISIBLE struct lws *
lws_adopt_socket(struct lws_context *context, lws_sockfd_type accept_fd)
{
	return lws_adopt_socket_vhost(context->vhost_list, accept_fd);
}

/* Common read-buffer adoption for lws_adopt_*_readbuf */
static struct lws*
adopt_socket_readbuf(struct lws *wsi, const char *readbuf, size_t len)
{
	struct lws_context_per_thread *pt;
	struct lws_pollfd *pfd;
	int n;

	if (!wsi)
		return NULL;

	if (!readbuf || len == 0)
		return wsi;

	if (wsi->position_in_fds_table == LWS_NO_FDS_POS)
		return wsi;

	pt = &wsi->context->pt[(int)wsi->tsi];

	n = lws_buflist_append_segment(&wsi->buflist, (const uint8_t *)readbuf,
				       len);
	if (n < 0)
		goto bail;
	if (n)
		lws_dll_lws_add_front(&wsi->dll_buflist, &pt->dll_head_buflist);

	/*
	 * we can't process the initial read data until we can attach an ah.
	 *
	 * if one is available, get it and place the data in his ah rxbuf...
	 * wsi with ah that have pending rxbuf get auto-POLLIN service.
	 *
	 * no autoservice because we didn't get a chance to attach the
	 * readbuf data to wsi or ah yet, and we will do it next if we get
	 * the ah.
	 */
	if (wsi->http.ah || !lws_header_table_attach(wsi, 0)) {

		lwsl_notice("%s: calling service on readbuf ah\n", __func__);

		/*
		 * unlike a normal connect, we have the headers already
		 * (or the first part of them anyway).
		 * libuv won't come back and service us without a network
		 * event, so we need to do the header service right here.
		 */
		pfd = &pt->fds[wsi->position_in_fds_table];
		pfd->revents |= LWS_POLLIN;
		lwsl_err("%s: calling service\n", __func__);
		if (lws_service_fd_tsi(wsi->context, pfd, wsi->tsi))
			/* service closed us */
			return NULL;

		return wsi;
	}
	lwsl_err("%s: deferring handling ah\n", __func__);

	return wsi;

bail:
	lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS,
			   "adopt skt readbuf fail");

	return NULL;
}

LWS_EXTERN struct lws *
lws_create_adopt_udp(struct lws_vhost *vhost, int port, int flags,
		     const char *protocol_name, struct lws *parent_wsi)
{
	lws_sock_file_fd_type sock;
	struct addrinfo h, *r, *rp;
	struct lws *wsi = NULL;
	char buf[16];
	int n;

	memset(&h, 0, sizeof(h));
	h.ai_family = AF_UNSPEC;    /* Allow IPv4 or IPv6 */
	h.ai_socktype = SOCK_DGRAM;
	h.ai_protocol = IPPROTO_UDP;
	h.ai_flags = AI_PASSIVE | AI_ADDRCONFIG;

	lws_snprintf(buf, sizeof(buf), "%u", port);
	n = getaddrinfo(NULL, buf, &h, &r);
	if (n) {
		lwsl_info("%s: getaddrinfo error: %s\n", __func__,
			  gai_strerror(n));
		goto bail;
	}

	for (rp = r; rp; rp = rp->ai_next) {
		sock.sockfd = socket(rp->ai_family, rp->ai_socktype,
				     rp->ai_protocol);
		if (sock.sockfd != LWS_SOCK_INVALID)
			break;
	}
	if (!rp) {
		lwsl_err("%s: unable to create INET socket\n", __func__);
		goto bail1;
	}

	if ((flags & LWS_CAUDP_BIND) && bind(sock.sockfd, rp->ai_addr,
#if defined(_WIN32)
			    (int)rp->ai_addrlen
#else
			    rp->ai_addrlen
#endif
	   ) == -1) {
		lwsl_err("%s: bind failed\n", __func__);
		goto bail2;
	}

	wsi = lws_adopt_descriptor_vhost(vhost, LWS_ADOPT_RAW_SOCKET_UDP, sock,
				        protocol_name, parent_wsi);
	if (!wsi)
		lwsl_err("%s: udp adoption failed\n", __func__);

bail2:
	if (!wsi)
		compatible_close((int)sock.sockfd);
bail1:
	freeaddrinfo(r);

bail:
	return wsi;
}

LWS_VISIBLE struct lws *
lws_adopt_socket_readbuf(struct lws_context *context, lws_sockfd_type accept_fd,
			 const char *readbuf, size_t len)
{
        return adopt_socket_readbuf(lws_adopt_socket(context, accept_fd),
				    readbuf, len);
}

LWS_VISIBLE struct lws *
lws_adopt_socket_vhost_readbuf(struct lws_vhost *vhost,
			       lws_sockfd_type accept_fd,
			       const char *readbuf, size_t len)
{
        return adopt_socket_readbuf(lws_adopt_socket_vhost(vhost, accept_fd),
				    readbuf, len);
}