/*
	  Copyright Red Hat, Inc. 2017
	
	  This program is free software; you can redistribute it and/or modify it
	  under the terms of the GNU General Public License as published by the
	  Free Software Foundation; either version 2, or (at your option) any
	  later version.
	
	  This program 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
	  General Public License for more details.
	
	  You should have received a copy of the GNU General Public License
	  along with this program; see the file COPYING.  If not, write to the
	  Free Software Foundation, Inc.,  675 Mass Ave, Cambridge, 
	  MA 02139, USA.
	*/
	#include "config.h"
	
	#include <unistd.h>
	#include <stdint.h>
	#include <stdlib.h>
	#include <stdio.h>
	#include <string.h>
	#include <signal.h>
	#include <errno.h>
	#include <nss.h>
	#include <sys/socket.h>
	#include <linux/vm_sockets.h>
	
	/* Local includes */
	#include "list.h"
	#include "simpleconfig.h"
	#include "static_map.h"
	#include "server_plugin.h"
	#include "history.h"
	#include "xvm.h"
	#include "simple_auth.h"
	#include "options.h"
	#include "mcast.h"
	#include "tcp.h"
	#include "tcp_listener.h"
	#include "debug.h"
	#include "fdops.h"
	
	#define NAME "vsock"
	#define VSOCK_VERSION "0.2"
	
	#define VSOCK_MAGIC 0xa32d27c1e
	
	#define VALIDATE(info) \
	do {\
		if (!info || info->magic != VSOCK_MAGIC)\
			return -EINVAL;\
	} while(0)
	
	typedef struct _vsock_options {
		char *key_file;
		int cid;
		unsigned int port;
		unsigned int hash;
		unsigned int auth;
		unsigned int flags;
	} vsock_options;
	
	
	typedef struct _vsock_info {
		uint64_t magic;
		void *priv;
		map_object_t *map;
		history_info_t *history;
		char key[MAX_KEY_LEN];
		vsock_options args;
		const fence_callbacks_t *cb;
		ssize_t key_len;
		int listen_sock;
	} vsock_info;
	
	
	struct vsock_hostlist_arg {
		map_object_t *map;
		int cid;
		int fd;
	};
	
	
	static int get_peer_cid(int fd, uint32_t *peer_cid) {
		struct sockaddr_vm svm;
		socklen_t len;
		int ret;
	
		if (!peer_cid)
			return -1;
	
		len = sizeof(svm);
		ret = getpeername(fd, (struct sockaddr *) &svm, &len);
		if (ret < 0) {
			printf("Error getting peer CID: %s\n", strerror(errno));
			return -1;
		}
	
		*peer_cid = svm.svm_cid;
		return 0;
	}
	
	
	/*
	 * See if we fenced this node recently (successfully)
	 * If so, ignore the request for a few seconds.
	 *
	 * We purge our history when the entries time out.
	 */
	static int
	check_history(void *a, void *b) {
		fence_req_t *old = a, *current = b;
	
		if (old->request == current->request &&
		    old->seqno == current->seqno &&
		    !strcasecmp((const char *)old->domain,
				(const char *)current->domain)) {
			return 1;
		}
		return 0;
	}
	
	
	static int 
	vsock_hostlist(const char *vm_name, const char *vm_uuid,
		       int state, void *priv)
	{
		struct vsock_hostlist_arg *arg = (struct vsock_hostlist_arg *) priv;

		host_state_t hinfo;
		struct timeval tv;
		int ret;
		uint32_t peer_cid = 0;
		char peer_cid_str[24];
	
		ret = get_peer_cid(arg->fd, &peer_cid);

		if (ret < 0) {
			printf("Unable to get peer CID: %s\n", strerror(errno));
			peer_cid_str[0] = '\0';

		} else

			snprintf(peer_cid_str, sizeof(peer_cid_str), "%u", peer_cid);
	
		/* Noops if auth == AUTH_NONE */
	

		if (map_check2(arg->map, peer_cid_str, vm_uuid, vm_name) == 0) {
			/* if we don't have access to fence this VM,
			 * we should not see it in a hostlist either */
			return 0;

		}
	
		strncpy((char *)hinfo.domain, vm_name, sizeof(hinfo.domain) - 1);
		strncpy((char *)hinfo.uuid, vm_uuid, sizeof(hinfo.uuid) - 1);
		hinfo.state = state;
	
		tv.tv_sec = 1;
		tv.tv_usec = 0;

		ret = _write_retry(arg->fd, &hinfo, sizeof(hinfo), &tv);
		if (ret == sizeof(hinfo))
			return 0;
		return 1;
	}
	
	
	static int
	vsock_hostlist_begin(int fd)
	{
		struct timeval tv;
		char val = (char) RESP_HOSTLIST;
	
		tv.tv_sec = 1;
		tv.tv_usec = 0;
		return _write_retry(fd, &val, 1, &tv);
	}
	
	
	static int 
	vsock_hostlist_end(int fd)
	{
		host_state_t hinfo;
		struct timeval tv;
		int ret;
	
		printf("Sending terminator packet\n");
	
		memset(&hinfo, 0, sizeof(hinfo));
	
		tv.tv_sec = 1;
		tv.tv_usec = 0;
		ret = _write_retry(fd, &hinfo, sizeof(hinfo), &tv);
		if (ret == sizeof(hinfo))
			return 0;
		return 1;
	}
	
	
	static int
	do_fence_request_vsock(int fd, fence_req_t *req, vsock_info *info)
	{
		char response = 1;
		struct vsock_hostlist_arg arg;
		uint32_t peer_cid = 0;
		char peer_cid_str[24];
		int ret;
	
		ret = get_peer_cid(fd, &peer_cid);
		if (ret < 0) {
			printf("Unable to get peer CID: %s\n", strerror(errno));
			return -1;
		}
	
		snprintf(peer_cid_str, sizeof(peer_cid_str), "%u", peer_cid);
	
		/* Noops if auth == AUTH_NONE */
		if (sock_response(fd, info->args.auth, info->key, info->key_len, 10) <= 0) {
			printf("CID %u Failed to respond to challenge\n", peer_cid);
			close(fd);
			return -1;
		}
	
		ret = sock_challenge(fd, info->args.auth, info->key, info->key_len, 10);
		if (ret <= 0) {
			printf("Remote CID %u failed challenge\n", peer_cid);
			close(fd);
			return -1;
		}
	
		dbg_printf(2, "Request %d seqno %d target %s from CID %u\n", 
			   req->request, req->seqno, req->domain, peer_cid);
	
		switch(req->request) {
		case FENCE_NULL:
			response = info->cb->null((char *)req->domain, info->priv);
			break;
		case FENCE_ON:
			if (map_check(info->map, peer_cid_str,
					     (const char *)req->domain) == 0) {
				response = RESP_PERM;
				break;
			}
			response = info->cb->on((char *)req->domain, peer_cid_str,
						req->seqno, info->priv);
			break;
		case FENCE_OFF:
			if (map_check(info->map, peer_cid_str,
					     (const char *)req->domain) == 0) {
				response = RESP_PERM;
				break;
			}
			response = info->cb->off((char *)req->domain, peer_cid_str,
						 req->seqno, info->priv);
			break;
		case FENCE_REBOOT:
			if (map_check(info->map, peer_cid_str,
					     (const char *)req->domain) == 0) {
				response = RESP_PERM;
				break;
			}
			response = info->cb->reboot((char *)req->domain, peer_cid_str,
						    req->seqno, info->priv);
			break;
		case FENCE_STATUS:
			if (map_check(info->map, peer_cid_str,
					     (const char *)req->domain) == 0) {
				response = RESP_PERM;
				break;
			}
			response = info->cb->status((char *)req->domain, info->priv);
			break;
		case FENCE_DEVSTATUS:
			response = info->cb->devstatus(info->priv);
			break;
		case FENCE_HOSTLIST:
			arg.map = info->map;
			arg.fd = fd;
	
			vsock_hostlist_begin(arg.fd);
			response = info->cb->hostlist(vsock_hostlist, &arg, info->priv);
			vsock_hostlist_end(arg.fd);
			break;
		}
	
		dbg_printf(3, "Sending response to caller CID %u...\n", peer_cid);
		if (_write_retry(fd, &response, 1, NULL) < 0)
			perror("write");
	
		history_record(info->history, req);
	
		if (fd != -1)
			close(fd);
	
		return 1;
	}
	
	
	static int
	vsock_dispatch(listener_context_t c, struct timeval *timeout)
	{
		vsock_info *info;
		fence_req_t data;
		fd_set rfds;
		int n;
		int client_fd;
	    int ret;
		struct timeval tv;
	
	    if (timeout != NULL)
	    	memcpy(&tv, timeout, sizeof(tv));
	    else {
	        tv.tv_sec = 1;
	        tv.tv_usec = 0;
	    }
	
		info = (vsock_info *) c;
		VALIDATE(info);
	
		FD_ZERO(&rfds);
		FD_SET(info->listen_sock, &rfds);
	
		n = select(info->listen_sock + 1, &rfds, NULL, NULL, timeout);
		if (n <= 0) {
			if (errno == EINTR || errno == EAGAIN)
				n = 0;
			else
				dbg_printf(2, "select: %s\n", strerror(errno));
			return n;
		}
	
		
		client_fd = accept(info->listen_sock, NULL, NULL);
		if (client_fd < 0) {
			perror("accept");
			return -1;
		}
	
		dbg_printf(3, "Accepted vsock client...\n");
	
		ret = _read_retry(client_fd, &data, sizeof(data), &tv);
		if (ret != sizeof(data)) {
			dbg_printf(3, "Invalid request (read %d bytes)\n", ret);
			close(client_fd);
			return 0;
		}
	
		swab_fence_req_t(&data);
	
		if (!verify_request(&data, info->args.hash, info->key, info->key_len)) {
			printf("Key mismatch; dropping client\n");
	        close(client_fd);
			return 0;
		}
	
		dbg_printf(3, "Request %d seqno %d domain %s\n",
			data.request, data.seqno, data.domain);
	
		if (history_check(info->history, &data) == 1) {
			printf("We just did this request; dropping client\n");
	        close(client_fd);
			return 0;
		}
			
		switch(info->args.auth) {
		case AUTH_NONE:
		case AUTH_SHA1:
		case AUTH_SHA256:
		case AUTH_SHA512:
			printf("VSOCK request\n");
			do_fence_request_vsock(client_fd, &data, info);
			break;
		default:
			printf("XXX Unhandled authentication\n");
		}
	
		return 0;
	}
	
	
	static int
	vsock_config(config_object_t *config, vsock_options *args)
	{
		char value[1024];
		int errors = 0;
	
		if (sc_get(config, "fence_virtd/@debug", value, sizeof(value))==0)
			dset(atoi(value));
	
		if (sc_get(config, "listeners/vsock/@key_file",
			   value, sizeof(value)-1) == 0) {
			dbg_printf(1, "Got %s for key_file\n", value);
			args->key_file = strdup(value);
		} else {
			args->key_file = strdup(DEFAULT_KEY_FILE);
			if (!args->key_file) {
				dbg_printf(1, "Failed to allocate memory\n");
				return -1;
			}
		}
	
		args->hash = DEFAULT_HASH;
		if (sc_get(config, "listeners/vsock/@hash",
			   value, sizeof(value)-1) == 0) {
			dbg_printf(1, "Got %s for hash\n", value);
			if (!strcasecmp(value, "none")) {
				args->hash = HASH_NONE;
			} else if (!strcasecmp(value, "sha1")) {
				args->hash = HASH_SHA1;
			} else if (!strcasecmp(value, "sha256")) {
				args->hash = HASH_SHA256;
			} else if (!strcasecmp(value, "sha512")) {
				args->hash = HASH_SHA512;
			} else {
				dbg_printf(1, "Unsupported hash: %s\n", value);
				++errors;
			}
		}
		
		args->auth = DEFAULT_AUTH;
		if (sc_get(config, "listeners/vsock/@auth",
			   value, sizeof(value)-1) == 0) {
			dbg_printf(1, "Got %s for auth\n", value);
			if (!strcasecmp(value, "none")) {
				args->hash = AUTH_NONE;
			} else if (!strcasecmp(value, "sha1")) {
				args->hash = AUTH_SHA1;
			} else if (!strcasecmp(value, "sha256")) {
				args->hash = AUTH_SHA256;
			} else if (!strcasecmp(value, "sha512")) {
				args->hash = AUTH_SHA512;
			} else {
				dbg_printf(1, "Unsupported auth: %s\n", value);
				++errors;
			}
		}
		
		args->port = DEFAULT_MCAST_PORT;
		if (sc_get(config, "listeners/vsock/@port",
			   value, sizeof(value)-1) == 0) {
			dbg_printf(1, "Got %s for port\n", value);
			args->port = atoi(value);
			if (args->port <= 0) {
				dbg_printf(1, "Invalid port: %s\n", value);
				++errors;
			}
		}
	
		return errors;
	}
	
	
	static int
	vsock_init(listener_context_t *c, const fence_callbacks_t *cb,
		   config_object_t *config, map_object_t *map, void *priv)
	{
		vsock_info *info;
		int listen_sock, ret;
		struct sockaddr_vm svm;
	
		if (NSS_NoDB_Init(NULL) != SECSuccess) {
			printf("Could not initialize NSS\n");
			return 1;
		}
	
		info = calloc(1, sizeof(*info));
		if (!info)
			return -1;
	
		info->priv = priv;
		info->cb = cb;
		info->map = map;
	
		ret = vsock_config(config, &info->args);
		if (ret < 0)
			perror("vsock_config");
		else if (ret > 0)
			printf("%d errors found during vsock listener configuration\n", ret);
	
		if (ret != 0) {
			if (info->args.key_file)
				free(info->args.key_file);
			free(info);
			return -1;
		}
	
		if (info->args.auth != AUTH_NONE || info->args.hash != HASH_NONE) {
			info->key_len = read_key_file(info->args.key_file,
						info->key, sizeof(info->key));
			if (info->key_len < 0) {
				printf("Could not read %s; operating without "
				       "authentication\n", info->args.key_file);
				info->args.auth = AUTH_NONE;
				info->args.hash = HASH_NONE;
				info->key_len = 0;
			}
		}
	
		listen_sock = socket(PF_VSOCK, SOCK_STREAM, 0);
		if (listen_sock < 0)
			goto out_fail;
	
		memset(&svm, 0, sizeof(svm));
		svm.svm_family = AF_VSOCK;
		svm.svm_cid = VMADDR_CID_ANY;
		svm.svm_port = info->args.port;
	
		if (bind(listen_sock, (struct sockaddr *) &svm, sizeof(svm)) < 0)
			goto out_fail;
	
		if (listen(listen_sock, 1) < 0)
			goto out_fail;
	
		info->magic = VSOCK_MAGIC;
		info->listen_sock = listen_sock;
		info->history = history_init(check_history, 10, sizeof(fence_req_t));
		*c = (listener_context_t)info;
		return 0;
	
	out_fail:
		printf("Could not set up listen socket: %s\n", strerror(errno));
		if (listen_sock >= 0)
			close(listen_sock);
		if (info->args.key_file)
			free(info->args.key_file);
		free(info);
		return -1;
	}
	
	
	static int
	vsock_shutdown(listener_context_t c)
	{
		vsock_info *info = (vsock_info *)c;
	
		VALIDATE(info);
		info->magic = 0;
		history_wipe(info->history);
		free(info->history);
		free(info->args.key_file);
		close(info->listen_sock);
		free(info);
	
		return 0;
	}
	
	
	static listener_plugin_t vsock_plugin = {
		.name = NAME,
		.version = VSOCK_VERSION,
		.init = vsock_init,
		.dispatch = vsock_dispatch,
		.cleanup = vsock_shutdown,
	};
	
	double
	LISTENER_VER_SYM(void)
	{
		return PLUGIN_VERSION_LISTENER;
	}
	
	const listener_plugin_t *
	LISTENER_INFO_SYM(void)
	{
		return &vsock_plugin;
	}