/*
	  Copyright Red Hat, Inc. 2006
	
	  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.
	*/
	/*
	 * Author: Lon Hohberger <lhh at redhat.com>
	 */
	
	#include "config.h"
	
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>
	#include <signal.h>
	#include <string.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <sys/wait.h>
	#include <sys/un.h>
	#include <sys/socket.h>
	#include <sys/select.h>
	#include <sys/ioctl.h>
	#include <arpa/inet.h>
	#include <net/if.h>
	#include <netinet/in.h>
	#include <netdb.h>
	#include <sys/time.h>
	#include <fcntl.h>
	#include <errno.h>
	#include <pthread.h>
	#include <nss.h>
	#include <libgen.h>
	
	/* Local includes */
	#include "xvm.h"
	#include "simple_auth.h"
	#include "options.h"
	#include "mcast.h"
	#include "tcp.h"
	#include "debug.h"
	#include "fdops.h"
	#include "list.h"
	#include "simpleconfig.h"
	#include "static_map.h"
	#include "server_plugin.h"
	#include "history.h"
	
	#define NAME "multicast"
	#define MCAST_VERSION "1.3"
	
	#define MCAST_MAGIC 0xabb911a3
	
	#define VALIDATE(info) \
	do {\
		if (!info || info->magic != MCAST_MAGIC)\
			return -EINVAL;\
	} while(0)
	
	typedef struct _mcast_options {
		char *addr;
		char *key_file;
		int ifindex;
		int family;
		unsigned int port;
		unsigned int hash;
		unsigned int auth;
		unsigned int flags;
	} mcast_options;
	
	
	typedef struct _mcast_info {
		uint64_t magic;
		void *priv;
		map_object_t *map;
		history_info_t *history;
		char key[MAX_KEY_LEN];
		mcast_options args;
		const fence_callbacks_t *cb;
		ssize_t key_len;
		int mc_sock;
		int need_kill;
	} mcast_info;
	
	
	struct mcast_hostlist_arg {
		map_object_t *map;
		const char *src;
		int fd;
	};
	
	
	/*
	 * 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
	connect_tcp(fence_req_t *req, fence_auth_type_t auth,
		    void *key, size_t key_len)
	{
		int fd = -1;
		struct sockaddr_in sin;
		struct sockaddr_in6 sin6;
		char buf[128];
	
		switch(req->family) {
		case PF_INET:
			memset(&sin, 0, sizeof(sin));
			memcpy(&sin.sin_addr, req->address,
			       sizeof(sin.sin_addr));
			sin.sin_family = PF_INET;
			fd = ipv4_connect(&sin.sin_addr, req->port,
					  5);
			if (fd < 0) {
				printf("Failed to call back\n");
				return -1;
			}
			break;
		case PF_INET6:
			memset(&sin6, 0, sizeof(sin6));
			memcpy(&sin6.sin6_addr, req->address,
			       sizeof(sin6.sin6_addr));
			sin.sin_family = PF_INET6;
			fd = ipv6_connect(&sin6.sin6_addr, req->port,
					  5);
	
			memset(buf,0,sizeof(buf));
			inet_ntop(PF_INET6, &sin6.sin6_addr, buf, sizeof(buf));
	
			if (fd < 0) {
				printf("Failed to call back %s\n", buf);
				return -1;
			}
			break;
		default:
			printf("Family = %d\n", req->family);
			return -1;
		}
	
		/* Noops if auth == AUTH_NONE */
		if (sock_response(fd, auth, key, key_len, 10) <= 0) {
			printf("Failed to respond to challenge\n");
			close(fd);
			return -1;
		}
	
		if (sock_challenge(fd, auth, key, key_len, 10) <= 0) {
			printf("Remote failed challenge\n");
			close(fd);
			return -1;
		}
		return fd;
	}
	
	
	static int 
	mcast_hostlist(const char *vm_name, const char *vm_uuid,
		       int state, void *priv)
	{
		struct mcast_hostlist_arg *arg = (struct mcast_hostlist_arg *)priv;

		host_state_t hinfo;
		struct timeval tv;
		int ret;
	

		if (map_check2(arg->map, arg->src, 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
	mcast_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 
	mcast_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_tcp(fence_req_t *req, mcast_info *info)
	{
		char ip_addr_src[1024];
		int fd = -1;
		char response = 1;
		struct mcast_hostlist_arg arg;
	
		fd = connect_tcp(req, info->args.auth, info->key, info->key_len);
		if (fd < 0) {
			dbg_printf(2, "Could not send reply to fence request: %s\n",
				strerror(errno));
			goto out;
		}
	
		inet_ntop(req->family, req->address,
			  ip_addr_src, sizeof(ip_addr_src));
	
		dbg_printf(2, "Request %d seqno %d src %s target %s\n", 
			   req->request, req->seqno, ip_addr_src, req->domain);
	
		switch(req->request) {
		case FENCE_NULL:
			response = info->cb->null((char *)req->domain, info->priv);
			break;
		case FENCE_ON:
			if (map_check(info->map, ip_addr_src,
					     (const char *)req->domain) == 0) {
				response = RESP_PERM;
				break;
			}
			response = info->cb->on((char *)req->domain, ip_addr_src,
						req->seqno, info->priv);
			break;
		case FENCE_OFF:
			if (map_check(info->map, ip_addr_src,
					     (const char *)req->domain) == 0) {
				response = RESP_PERM;
				break;
			}
			response = info->cb->off((char *)req->domain, ip_addr_src,
						 req->seqno, info->priv);
			break;
		case FENCE_REBOOT:
			if (map_check(info->map, ip_addr_src,
					     (const char *)req->domain) == 0) {
				response = RESP_PERM;
				break;
			}
			response = info->cb->reboot((char *)req->domain, ip_addr_src,
						    req->seqno, info->priv);
			break;
		case FENCE_STATUS:
			if (map_check(info->map, ip_addr_src,
					     (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.src = ip_addr_src;
			arg.fd = fd;
	
			mcast_hostlist_begin(arg.fd);
			response = info->cb->hostlist(mcast_hostlist, &arg,
						      info->priv);
			mcast_hostlist_end(arg.fd);
			break;
		}
	
		dbg_printf(3, "Sending response to caller...\n");
		if (_write_retry(fd, &response, 1, NULL) < 0) {
			perror("write");
		}
	
		/* XVM shotguns multicast packets, so we want to avoid 
		 * acting on the same request multiple times if the first
		 * attempt was successful.
		 */
		history_record(info->history, req);
	out:
		if (fd != -1)
			close(fd);
	
		return 1;
	}
	
	
	static int
	mcast_dispatch(listener_context_t c, struct timeval *timeout)
	{
		mcast_info *info;
		fence_req_t data;
		fd_set rfds;
		struct sockaddr_in sin;
		int len;
		int n;
		socklen_t slen;
	
		info = (mcast_info *)c;
		VALIDATE(info);
	
		FD_ZERO(&rfds);
		FD_SET(info->mc_sock, &rfds);
	
		n = select((info->mc_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;
		}
		
		slen = sizeof(sin);
		len = recvfrom(info->mc_sock, &data, sizeof(data), 0,
			       (struct sockaddr *)&sin, &slen);
			
		if (len <= 0) {
			perror("recvfrom");
			return len;
		}
	
		swab_fence_req_t(&data);
	
		if (!verify_request(&data, info->args.hash, info->key,
				    info->key_len)) {
			printf("Key mismatch; dropping packet\n");
			return 0;
		}
	
		printf("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 packet\n");
			return 0;
		}
			
		switch(info->args.auth) {
		case AUTH_NONE:
		case AUTH_SHA1:
		case AUTH_SHA256:
		case AUTH_SHA512:
			printf("Plain TCP request\n");
			do_fence_request_tcp(&data, info);
			break;
		default:
			printf("XXX Unhandled authentication\n");
		}
	
		return 0;
	}
	
	
	static int
	mcast_config(config_object_t *config, mcast_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/multicast/@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/multicast/@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/multicast/@auth",
			   value, sizeof(value)-1) == 0) {
			dbg_printf(1, "Got %s for auth\n", value);
			if (!strcasecmp(value, "none")) {
				args->auth = AUTH_NONE;
			} else if (!strcasecmp(value, "sha1")) {
				args->auth = AUTH_SHA1;
			} else if (!strcasecmp(value, "sha256")) {
				args->auth = AUTH_SHA256;
			} else if (!strcasecmp(value, "sha512")) {
				args->auth = AUTH_SHA512;
			} else {
				dbg_printf(1, "Unsupported auth: %s\n", value);
				++errors;
			}
		}
		
		args->family = PF_INET;
		if (sc_get(config, "listeners/multicast/@family",
			   value, sizeof(value)-1) == 0) {
			dbg_printf(1, "Got %s for family\n", value);
			if (!strcasecmp(value, "ipv4")) {
				args->family = PF_INET;
			} else if (!strcasecmp(value, "ipv6")) {
				args->family = PF_INET6;
			} else {
				dbg_printf(1, "Unsupported family: %s\n", value);
				++errors;
			}
		}
	
		if (sc_get(config, "listeners/multicast/@address",
			   value, sizeof(value)-1) == 0) {
			dbg_printf(1, "Got %s for address\n", value);
			args->addr = strdup(value);
		} else {
			if (args->family == PF_INET) {
				args->addr = strdup(IPV4_MCAST_DEFAULT);
			} else {
				args->addr = strdup(IPV6_MCAST_DEFAULT);
			}
		}
		if (!args->addr) {
			return -1;
		}
	
		args->port = DEFAULT_MCAST_PORT;
		if (sc_get(config, "listeners/multicast/@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;
			}
		}
	
		args->ifindex = 0;
		if (sc_get(config, "listeners/multicast/@interface",
			   value, sizeof(value)-1) == 0) {
			dbg_printf(1, "Got %s for interface\n", value);
			args->ifindex = if_nametoindex(value);
			if (args->ifindex < 0) {
				dbg_printf(1, "Invalid interface: %s\n", value);
				++errors;
			}
		}
	
		return errors;
	}
	
	
	static int
	mcast_init(listener_context_t *c, const fence_callbacks_t *cb,
		   config_object_t *config, map_object_t *map, void *priv)
	{
		mcast_info *info;
		int mc_sock, ret;
	
		/* Initialize NSS; required to do hashing, as silly as that
		   sounds... */
		if (NSS_NoDB_Init(NULL) != SECSuccess) {
			printf("Could not initialize NSS\n");
			return 1;
		}
	
		info = malloc(sizeof(*info));
		if (!info)
			return -1;
		memset(info, 0, sizeof(*info));
	
		info->priv = priv;
		info->cb = cb;
		info->map = map;
	
		ret = mcast_config(config, &info->args);
		if (ret < 0) {
			perror("mcast_config");
			free(info);
			return -1;
		} else if (ret > 0) {
			printf("%d errors found during configuration\n",ret);
			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;
			}
		}
	
		if (info->args.family == PF_INET)
			mc_sock = ipv4_recv_sk(info->args.addr,
					       info->args.port,
					       info->args.ifindex);
		else
			mc_sock = ipv6_recv_sk(info->args.addr,
					       info->args.port,
					       info->args.ifindex);
		if (mc_sock < 0) {
			printf("Could not set up multicast listen socket\n");
			free(info);
			return -1;
		}
	
		info->magic = MCAST_MAGIC;
		info->mc_sock = mc_sock;
		info->history = history_init(check_history, 10, sizeof(fence_req_t));
		*c = (listener_context_t)info;
		return 0;
	}
	
	
	static int
	mcast_shutdown(listener_context_t c)
	{
		mcast_info *info = (mcast_info *)c;
	
		VALIDATE(info);
		info->magic = 0;
		history_wipe(info->history);
		free(info->history);
		free(info->args.key_file);
		free(info->args.addr);
		close(info->mc_sock);
		free(info);
	
		return 0;
	}
	
	
	static listener_plugin_t mcast_plugin = {
		.name = NAME,
		.version = MCAST_VERSION,
		.init = mcast_init,
		.dispatch = mcast_dispatch,
		.cleanup = mcast_shutdown,
	};
	
	double
	LISTENER_VER_SYM(void)
	{
		return PLUGIN_VERSION_LISTENER;
	}
	
	const listener_plugin_t *
	LISTENER_INFO_SYM(void)
	{
		return &mcast_plugin;
	}