path: root/src/server.c

/*
 * Server management functions.
 *
 * Copyright 2000-2012 Willy Tarreau <w@1wt.eu>
 * Copyright 2007-2008 Krzysztof Piotr Oledzki <ole@ans.pl>
 *
 * 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 of the License, or (at your option) any later version.
 *
 */

#include <sys/types.h>
#include <netinet/tcp.h>
#include <ctype.h>
#include <errno.h>

#include <import/ebmbtree.h>

#include <haproxy/api.h>
#include <haproxy/applet-t.h>
#include <haproxy/backend.h>
#include <haproxy/cfgparse.h>
#include <haproxy/check.h>
#include <haproxy/cli.h>
#include <haproxy/connection.h>
#include <haproxy/dict-t.h>
#include <haproxy/errors.h>
#include <haproxy/global.h>
#include <haproxy/guid.h>
#include <haproxy/log.h>
#include <haproxy/mailers.h>
#include <haproxy/namespace.h>
#include <haproxy/port_range.h>
#include <haproxy/protocol.h>
#include <haproxy/proxy.h>
#include <haproxy/queue.h>
#include <haproxy/resolvers.h>
#include <haproxy/sample.h>
#include <haproxy/sc_strm.h>
#include <haproxy/server.h>
#include <haproxy/stats.h>
#include <haproxy/stconn.h>
#include <haproxy/stream.h>
#include <haproxy/task.h>
#include <haproxy/tcpcheck.h>
#include <haproxy/time.h>
#include <haproxy/tools.h>
#include <haproxy/xxhash.h>
#include <haproxy/event_hdl.h>


static void srv_update_status(struct server *s, int type, int cause);
static int srv_apply_lastaddr(struct server *srv, int *err_code);
static void srv_cleanup_connections(struct server *srv);

/* extra keywords used as value for other arguments. They are used as
 * suggestions for mistyped words.
 */
static const char *extra_kw_list[] = {
	"ipv4", "ipv6", "legacy", "octet-count",
	"fail-check", "sudden-death", "mark-down",
	NULL /* must be last */
};

/* List head of all known server keywords */
struct srv_kw_list srv_keywords = {
	.list = LIST_HEAD_INIT(srv_keywords.list)
};

__decl_thread(HA_SPINLOCK_T idle_conn_srv_lock);
struct eb_root idle_conn_srv = EB_ROOT;
struct task *idle_conn_task __read_mostly = NULL;
struct list servers_list = LIST_HEAD_INIT(servers_list);
static struct task *server_atomic_sync_task = NULL;
static event_hdl_async_equeue server_atomic_sync_queue;

/* SERVER DELETE(n)->ADD global tracker:
 * This is meant to provide srv->rid (revision id) value.
 * Revision id allows to differentiate between a previously existing
 * deleted server and a new server reusing deleted server name/id.
 *
 * start value is 0 (even value)
 * LSB is used to specify that one or multiple srv delete in a row
 * were performed.
 * When adding a new server, increment by 1 if current
 * value is odd (odd = LSB set),
 * because adding a new server after one or
 * multiple deletions means we could potentially be reusing old names:
 * Increase the revision id to prevent mixups between old and new names.
 *
 * srv->rid is calculated from cnt even values only.
 * sizeof(srv_id_reuse_cnt) must be twice sizeof(srv->rid)
 *
 * Wraparound is expected and should not cause issues
 * (with current design we allow up to 4 billion unique revisions)
 *
 * Counter is only used under thread_isolate (cli_add/cli_del),
 * no need for atomic ops.
 */
static uint64_t srv_id_reuse_cnt = 0;

/* The server names dictionary */
struct dict server_key_dict = {
	.name = "server keys",
	.values = EB_ROOT_UNIQUE,
};

static const char *srv_adm_st_chg_cause_str[] = {
	[SRV_ADM_STCHGC_NONE] = "",
	[SRV_ADM_STCHGC_DNS_NOENT] = "entry removed from SRV record",
	[SRV_ADM_STCHGC_DNS_NOIP] = "No IP for server ",
	[SRV_ADM_STCHGC_DNS_NX] = "DNS NX status",
	[SRV_ADM_STCHGC_DNS_TIMEOUT] = "DNS timeout status",
	[SRV_ADM_STCHGC_DNS_REFUSED] = "DNS refused status",
	[SRV_ADM_STCHGC_DNS_UNSPEC] = "unspecified DNS error",
	[SRV_ADM_STCHGC_STATS_DISABLE] = "'disable' on stats page",
	[SRV_ADM_STCHGC_STATS_STOP] = "'stop' on stats page"
};

const char *srv_adm_st_chg_cause(enum srv_adm_st_chg_cause cause)
{
	return srv_adm_st_chg_cause_str[cause];
}

static const char *srv_op_st_chg_cause_str[] = {
	[SRV_OP_STCHGC_NONE] = "",
	[SRV_OP_STCHGC_HEALTH] = "",
	[SRV_OP_STCHGC_AGENT] = "",
	[SRV_OP_STCHGC_CLI] = "changed from CLI",
	[SRV_OP_STCHGC_LUA] = "changed from Lua script",
	[SRV_OP_STCHGC_STATS_WEB] = "changed from Web interface",
	[SRV_OP_STCHGC_STATEFILE] = "changed from server-state after a reload"
};

const char *srv_op_st_chg_cause(enum srv_op_st_chg_cause cause)
{
	return srv_op_st_chg_cause_str[cause];
}

int srv_downtime(const struct server *s)
{
	if ((s->cur_state != SRV_ST_STOPPED) || s->counters.last_change >= ns_to_sec(now_ns))		// ignore negative time
		return s->down_time;

	return ns_to_sec(now_ns) - s->counters.last_change + s->down_time;
}

int srv_getinter(const struct check *check)
{
	const struct server *s = check->server;

	if ((check->state & (CHK_ST_CONFIGURED|CHK_ST_FASTINTER)) == CHK_ST_CONFIGURED &&
	    (check->health == check->rise + check->fall - 1))
		return check->inter;

	if ((s->next_state == SRV_ST_STOPPED) && check->health == 0)
		return (check->downinter)?(check->downinter):(check->inter);

	return (check->fastinter)?(check->fastinter):(check->inter);
}

/* Update server's addr:svc_port tuple in INET context
 *
 * Must be called under thread isolation to ensure consistent readings across
 * all threads (addr:svc_port might be read without srv lock being held).
 */
static void _srv_set_inetaddr_port(struct server *srv,
                                   const struct sockaddr_storage *addr,
                                   unsigned int svc_port, uint8_t mapped_port)
{
	ipcpy(addr, &srv->addr);
	srv->svc_port = svc_port;
	if (mapped_port)
		srv->flags |= SRV_F_MAPPORTS;
	else
		srv->flags &= ~SRV_F_MAPPORTS;

	if (srv->proxy->lbprm.update_server_eweight) {
		/* some balancers (chash in particular) may use the addr in their routing decisions */
		srv->proxy->lbprm.update_server_eweight(srv);
	}

	if (srv->log_target && srv->log_target->type == LOG_TARGET_DGRAM) {
		/* server is used as a log target, manually update log target addr for DGRAM */
		ipcpy(addr, srv->log_target->addr);
		set_host_port(srv->log_target->addr, svc_port);
	}
}

/* same as _srv_set_inetaddr_port() but only updates the addr part
 */
static void _srv_set_inetaddr(struct server *srv,
                              const struct sockaddr_storage *addr)
{
	_srv_set_inetaddr_port(srv, addr, srv->svc_port, !!(srv->flags & SRV_F_MAPPORTS));
}

/*
 * Function executed by server_atomic_sync_task to perform atomic updates on
 * compatible server struct members that are not guarded by any lock since
 * they are not supposed to change often and are subject to being used in
 * sensitive codepaths
 *
 * Some updates may require thread isolation: we start without isolation
 * but as soon as we encounter an event that requires isolation, we do so.
 * Once the event is processed, we keep the isolation until we've processed
 * the whole batch of events and leave isolation once we're done, as it would
 * be very costly to try to acquire isolation multiple times in a row.
 * The task will limit itself to a number of events per run to prevent
 * thread contention (see: "tune.events.max-events-at-once").
 *
 * TODO: if we find out that enforcing isolation is too costly, we may
 * consider adding thread_isolate_try_full(timeout) or equivalent to the
 * thread API so that we can do our best not to block harmless threads
 * for too long if one or multiple threads are still heavily busy. This
 * would mean that the task would be capable of rescheduling itself to
 * start again on the current event if it failed to acquire thread
 * isolation. This would also imply that the event_hdl API allows us
 * to check an event without popping it from the queue first (remove the
 * event once it is successfully processed).
 */
static void srv_set_addr_desc(struct server *s, int reattach);
static struct task *server_atomic_sync(struct task *task, void *context, unsigned int state)
{
	unsigned int remain = event_hdl_tune.max_events_at_once; // to limit max number of events per batch
	struct event_hdl_async_event *event;

	/* check for new server events that we care about */
	while ((event = event_hdl_async_equeue_pop(&server_atomic_sync_queue))) {
		if (event_hdl_sub_type_equal(event->type, EVENT_HDL_SUB_END)) {
			/* ending event: no more events to come */
			event_hdl_async_free_event(event);
			task_destroy(task);
			task = NULL;
			break;
		}

		if (!remain) {
			/* STOP: we've already spent all our budget here, and
			 * considering we possibly are under isolation, we cannot
		         * keep blocking other threads any longer.
			 *
			 * Reschedule the task to finish where we left off if
			 * there are remaining events in the queue.
			 */
			if (!event_hdl_async_equeue_isempty(&server_atomic_sync_queue))
				task_wakeup(task, TASK_WOKEN_OTHER);
			break;
		}
		remain--;

		/* new event to process */
		if (event_hdl_sub_type_equal(event->type, EVENT_HDL_SUB_SERVER_INETADDR)) {
			struct sockaddr_storage new_addr;
			struct event_hdl_cb_data_server_inetaddr *data = event->data;
			struct proxy *px;
			struct server *srv;

			/* server ip:port changed, we must atomically update data members
			 * to prevent invalid reads by other threads.
			 */

			/* check if related server still exists */
			px = proxy_find_by_id(data->server.safe.proxy_uuid, PR_CAP_BE, 0);
			if (!px)
				continue;
			srv = server_find_by_id_unique(px, data->server.safe.puid, data->server.safe.rid);
			if (!srv)
				continue;

			/* prepare new addr based on event cb data */
			memset(&new_addr, 0, sizeof(new_addr));
			new_addr.ss_family = data->safe.next.family;
			switch (new_addr.ss_family) {
				case AF_INET:
					((struct sockaddr_in *)&new_addr)->sin_addr.s_addr =
						data->safe.next.addr.v4.s_addr;
					break;
				case AF_INET6:
					memcpy(&((struct sockaddr_in6 *)&new_addr)->sin6_addr,
					       &data->safe.next.addr.v6,
					       sizeof(struct in6_addr));
					break;
				case AF_UNSPEC:
					/* addr reset, nothing to do */
					break;
				default:
					/* should not happen */
					break;
			}
			/*
			 * this requires thread isolation, which is safe since we're the only
			 * task working for the current subscription and we don't hold locks
			 * or resources that other threads may depend on to complete a running
			 * cycle. Note that we do this way because we assume that this event is
			 * rather rare.
			 */
			if (!thread_isolated())
				thread_isolate_full();

			/* apply new addr:port combination */
			_srv_set_inetaddr_port(srv, &new_addr,
			                       data->safe.next.port.svc, data->safe.next.port.map);

			/* propagate the changes, force connection cleanup */
			if (new_addr.ss_family != AF_UNSPEC &&
			    (srv->next_admin & SRV_ADMF_RMAINT)) {
				/* server was previously put under DNS maintenance due
				 * to DNS error, but addr resolves again, so we must
				 * put it out of maintenance
				 */
				srv_clr_admin_flag(srv, SRV_ADMF_RMAINT);

				/* thanks to valid DNS resolution? */
				if (data->safe.updater.dns) {
					chunk_reset(&trash);
					chunk_printf(&trash, "Server %s/%s administratively READY thanks to valid DNS answer", srv->proxy->id, srv->id);
					ha_warning("%s.\n", trash.area);
					send_log(srv->proxy, LOG_NOTICE, "%s.\n", trash.area);
				}
			}
			srv_cleanup_connections(srv);
			srv_set_dyncookie(srv);
			srv_set_addr_desc(srv, 1);
		}
		event_hdl_async_free_event(event);
	}

	/* some events possibly required thread_isolation:
	 * now that we are done, we must leave thread isolation before
	 * returning
	 */
	if (thread_isolated())
		thread_release();

	return task;
}

/* Try to start the atomic server sync task.
 *
 * Returns ERR_NONE on success and a combination of ERR_CODE on failure
 */
static int server_atomic_sync_start()
{
	struct event_hdl_sub_type subscriptions = EVENT_HDL_SUB_NONE;

	if (server_atomic_sync_task)
		return ERR_NONE; // nothing to do
	server_atomic_sync_task = task_new_anywhere();
	if (!server_atomic_sync_task)
		goto fail;
	server_atomic_sync_task->process = server_atomic_sync;
	event_hdl_async_equeue_init(&server_atomic_sync_queue);

	/* task created, now subscribe to relevant server events in the global list */
	subscriptions = event_hdl_sub_type_add(subscriptions, EVENT_HDL_SUB_SERVER_INETADDR);
	if (!event_hdl_subscribe(NULL, subscriptions,
	                         EVENT_HDL_ASYNC_TASK(&server_atomic_sync_queue,
	                                              server_atomic_sync_task,
	                                              NULL,
	                                              NULL)))
		goto fail;


	return ERR_NONE;

 fail:
	task_destroy(server_atomic_sync_task);
	server_atomic_sync_task = NULL;
	return ERR_ALERT | ERR_FATAL;
}
REGISTER_POST_CHECK(server_atomic_sync_start);

/* fill common server event data members struct
 * must be called with server lock or under thread isolate
 */
static inline void _srv_event_hdl_prepare(struct event_hdl_cb_data_server *cb_data,
                                          struct server *srv, uint8_t thread_isolate)
{
	/* safe data assignments */
	cb_data->safe.puid = srv->puid;
	cb_data->safe.rid = srv->rid;
	cb_data->safe.flags = srv->flags;
	snprintf(cb_data->safe.name, sizeof(cb_data->safe.name), "%s", srv->id);
	cb_data->safe.proxy_name[0] = '\0';
	cb_data->safe.proxy_uuid = -1; /* default value */
	if (srv->proxy) {
		cb_data->safe.proxy_uuid = srv->proxy->uuid;
		snprintf(cb_data->safe.proxy_name, sizeof(cb_data->safe.proxy_name), "%s", srv->proxy->id);
	}
	/* unsafe data assignments */
	cb_data->unsafe.ptr = srv;
	cb_data->unsafe.thread_isolate = thread_isolate;
	cb_data->unsafe.srv_lock = !thread_isolate;
}

/* take an event-check snapshot from a live check */
void _srv_event_hdl_prepare_checkres(struct event_hdl_cb_data_server_checkres *checkres,
                                     struct check *check)
{
	checkres->agent = !!(check->state & CHK_ST_AGENT);
	checkres->result = check->result;
	checkres->duration = check->duration;
	checkres->reason.status = check->status;
	checkres->reason.code = check->code;
	checkres->health.cur = check->health;
	checkres->health.rise = check->rise;
	checkres->health.fall = check->fall;
}

/* Prepare SERVER_STATE event
 *
 * This special event will contain extra hints related to the state change
 *
 * Must be called with server lock held
 */
void _srv_event_hdl_prepare_state(struct event_hdl_cb_data_server_state *cb_data,
                                  struct server *srv, int type, int cause,
                                  enum srv_state prev_state, int requeued)
{
	/* state event provides additional info about the server state change */
	cb_data->safe.type = type;
	cb_data->safe.new_state = srv->cur_state;
	cb_data->safe.old_state = prev_state;
	cb_data->safe.requeued = requeued;
	if (type) {
		/* administrative */
		cb_data->safe.adm_st_chg.cause = cause;
	}
	else {
		/* operational */
		cb_data->safe.op_st_chg.cause = cause;
		if (cause == SRV_OP_STCHGC_HEALTH || cause == SRV_OP_STCHGC_AGENT) {
			struct check *check = (cause == SRV_OP_STCHGC_HEALTH) ? &srv->check : &srv->agent;

			/* provide additional check-related state change result */
			_srv_event_hdl_prepare_checkres(&cb_data->safe.op_st_chg.check, check);
		}
	}
}

/* Prepare SERVER_INETADDR event, prev data is learned from the current
 * server settings.
 *
 * This special event will contain extra hints related to the addr change
 *
 * Must be called with the server lock held.
 */
static void _srv_event_hdl_prepare_inetaddr(struct event_hdl_cb_data_server_inetaddr *cb_data,
                                            struct server *srv,
                                            const struct server_inetaddr *next_inetaddr,
                                            struct server_inetaddr_updater updater)
{
	struct server_inetaddr prev_inetaddr;

	server_get_inetaddr(srv, &prev_inetaddr);

	/* only INET families are supported */
	BUG_ON((next_inetaddr->family != AF_UNSPEC &&
	        next_inetaddr->family != AF_INET && next_inetaddr->family != AF_INET6));

	/* prev */
	cb_data->safe.prev = prev_inetaddr;

	/* next */
	cb_data->safe.next = *next_inetaddr;

	/* updater */
	cb_data->safe.updater = updater;
}

/* server event publishing helper: publish in both global and
 * server dedicated subscription list.
 */
#define _srv_event_hdl_publish(e, d, s)                                 \
        ({                                                              \
                /* publish in server dedicated sub list */              \
                event_hdl_publish(&s->e_subs, e, EVENT_HDL_CB_DATA(&d));\
                /* publish in global subscription list */               \
                event_hdl_publish(NULL, e, EVENT_HDL_CB_DATA(&d));      \
        })

/* General server event publishing:
 * Use this to publish EVENT_HDL_SUB_SERVER family type event
 * from srv facility.
 *
 * server ptr must be valid.
 * Must be called with srv lock or under thread_isolate.
 */
static void srv_event_hdl_publish(struct event_hdl_sub_type event,
                                  struct server *srv, uint8_t thread_isolate)
{
	struct event_hdl_cb_data_server cb_data;

	/* prepare event data */
	_srv_event_hdl_prepare(&cb_data, srv, thread_isolate);
	_srv_event_hdl_publish(event, cb_data, srv);
}

/* Publish SERVER_CHECK event
 *
 * This special event will contain extra hints related to the check itself
 *
 * Must be called with server lock held
 */
void srv_event_hdl_publish_check(struct server *srv, struct check *check)
{
	struct event_hdl_cb_data_server_check cb_data;

	/* check event provides additional info about the server check */
	_srv_event_hdl_prepare_checkres(&cb_data.safe.res, check);

	cb_data.unsafe.ptr = check;

	/* prepare event data (common server data) */
	_srv_event_hdl_prepare((struct event_hdl_cb_data_server *)&cb_data, srv, 0);

	_srv_event_hdl_publish(EVENT_HDL_SUB_SERVER_CHECK, cb_data, srv);
}

/*
 * Check that we did not get a hash collision.
 * Unlikely, but it can happen. The server's proxy must be at least
 * read-locked.
 */
static inline void srv_check_for_dup_dyncookie(struct server *s)
{
	struct proxy *p = s->proxy;
	struct server *tmpserv;

	for (tmpserv = p->srv; tmpserv != NULL;
	    tmpserv = tmpserv->next) {
		if (tmpserv == s)
			continue;
		if (tmpserv->next_admin & SRV_ADMF_FMAINT)
			continue;
		if (tmpserv->cookie &&
		    strcmp(tmpserv->cookie, s->cookie) == 0) {
			ha_warning("We generated two equal cookies for two different servers.\n"
				   "Please change the secret key for '%s'.\n",
				   s->proxy->id);
		}
	}

}

/*
 * Must be called with the server lock held, and will read-lock the proxy.
 */
void srv_set_dyncookie(struct server *s)
{
	struct proxy *p = s->proxy;
	char *tmpbuf;
	unsigned long long hash_value;
	size_t key_len;
	size_t buffer_len;
	int addr_len;
	int port;

	HA_RWLOCK_RDLOCK(PROXY_LOCK, &p->lock);

	if ((s->flags & SRV_F_COOKIESET) ||
	    !(s->proxy->ck_opts & PR_CK_DYNAMIC) ||
	    s->proxy->dyncookie_key == NULL)
		goto out;
	key_len = strlen(p->dyncookie_key);

	if (s->addr.ss_family != AF_INET &&
	    s->addr.ss_family != AF_INET6)
		goto out;
	/*
	 * Buffer to calculate the cookie value.
	 * The buffer contains the secret key + the server IP address
	 * + the TCP port.
	 */
	addr_len = (s->addr.ss_family == AF_INET) ? 4 : 16;
	/*
	 * The TCP port should use only 2 bytes, but is stored in
	 * an unsigned int in struct server, so let's use 4, to be
	 * on the safe side.
	 */
	buffer_len = key_len + addr_len + 4;
	tmpbuf = trash.area;
	memcpy(tmpbuf, p->dyncookie_key, key_len);
	memcpy(&(tmpbuf[key_len]),
	    s->addr.ss_family == AF_INET ?
	    (void *)&((struct sockaddr_in *)&s->addr)->sin_addr.s_addr :
	    (void *)&(((struct sockaddr_in6 *)&s->addr)->sin6_addr.s6_addr),
	    addr_len);
	/*
	 * Make sure it's the same across all the load balancers,
	 * no matter their endianness.
	 */
	port = htonl(s->svc_port);
	memcpy(&tmpbuf[key_len + addr_len], &port, 4);
	hash_value = XXH64(tmpbuf, buffer_len, 0);
	memprintf(&s->cookie, "%016llx", hash_value);
	if (!s->cookie)
		goto out;
	s->cklen = 16;

	/* Don't bother checking if the dyncookie is duplicated if
	 * the server is marked as "disabled", maybe it doesn't have
	 * its real IP yet, but just a place holder.
	 */
	if (!(s->next_admin & SRV_ADMF_FMAINT))
		srv_check_for_dup_dyncookie(s);
 out:
	HA_RWLOCK_RDUNLOCK(PROXY_LOCK, &p->lock);
}

/* Returns true if it's possible to reuse an idle connection from server <srv>
 * for a websocket stream. This is the case if server is configured to use the
 * same protocol for both HTTP and websocket streams. This depends on the value
 * of "proto", "alpn" and "ws" keywords.
 */
int srv_check_reuse_ws(struct server *srv)
{
	if (srv->mux_proto || srv->use_ssl != 1 || !srv->ssl_ctx.alpn_str) {
		/* explicit srv.mux_proto or no ALPN : srv.mux_proto is used
		 * for mux selection.
		 */
		const struct ist srv_mux = srv->mux_proto ?
		                           srv->mux_proto->token : IST_NULL;

		switch (srv->ws) {
		/* "auto" means use the same protocol : reuse is possible. */
		case SRV_WS_AUTO:
			return 1;

		/* "h2" means use h2 for websocket : reuse is possible if
		 * server mux is h2.
		 */
		case SRV_WS_H2:
			if (srv->mux_proto && isteq(srv_mux, ist("h2")))
				return 1;
			break;

		/* "h1" means use h1 for websocket : reuse is possible if
		 * server mux is h1.
		 */
		case SRV_WS_H1:
			if (!srv->mux_proto || isteq(srv_mux, ist("h1")))
				return 1;
			break;
		}
	}
	else {
		/* ALPN selection.
		 * Based on the assumption that only "h2" and "http/1.1" token
		 * are used on server ALPN.
		 */
		const struct ist alpn = ist2(srv->ssl_ctx.alpn_str,
		                             srv->ssl_ctx.alpn_len);

		switch (srv->ws) {
		case SRV_WS_AUTO:
			/* for auto mode, consider reuse as possible if the
			 * server uses a single protocol ALPN
			 */
			if (!istchr(alpn, ','))
				return 1;
			break;

		case SRV_WS_H2:
			return isteq(alpn, ist("\x02h2"));

		case SRV_WS_H1:
			return isteq(alpn, ist("\x08http/1.1"));
		}
	}

	return 0;
}

/* Return the proto to used for a websocket stream on <srv> without ALPN. NULL
 * is a valid value indicating to use the fallback mux.
 */
const struct mux_ops *srv_get_ws_proto(struct server *srv)
{
	const struct mux_proto_list *mux = NULL;

	switch (srv->ws) {
	case SRV_WS_AUTO:
		mux = srv->mux_proto;
		break;

	case SRV_WS_H1:
		mux = get_mux_proto(ist("h1"));
		break;

	case SRV_WS_H2:
		mux = get_mux_proto(ist("h2"));
		break;
	}

	return mux ? mux->mux : NULL;
}

/*
 * Must be called with the server lock held. The server is first removed from
 * the proxy tree if it was already attached. If <reattach> is true, the server
 * will then be attached in the proxy tree. The proxy lock is held to
 * manipulate the tree.
 */
static void srv_set_addr_desc(struct server *s, int reattach)
{
	struct proxy *p = s->proxy;
	char *key;

	key = sa2str(&s->addr, s->svc_port, s->flags & SRV_F_MAPPORTS);

	if (s->addr_node.key) {
		if (key && strcmp(key, s->addr_node.key) == 0) {
			free(key);
			return;
		}

		HA_RWLOCK_WRLOCK(PROXY_LOCK, &p->lock);
		ebpt_delete(&s->addr_node);
		HA_RWLOCK_WRUNLOCK(PROXY_LOCK, &p->lock);

		free(s->addr_node.key);
	}

	s->addr_node.key = key;

	if (reattach) {
		if (s->addr_node.key) {
			HA_RWLOCK_WRLOCK(PROXY_LOCK, &p->lock);
			ebis_insert(&p->used_server_addr, &s->addr_node);
			HA_RWLOCK_WRUNLOCK(PROXY_LOCK, &p->lock);
		}
	}
}

/*
 * Registers the server keyword list <kwl> as a list of valid keywords for next
 * parsing sessions.
 */
void srv_register_keywords(struct srv_kw_list *kwl)
{
	LIST_APPEND(&srv_keywords.list, &kwl->list);
}

/* Return a pointer to the server keyword <kw>, or NULL if not found. If the
 * keyword is found with a NULL ->parse() function, then an attempt is made to
 * find one with a valid ->parse() function. This way it is possible to declare
 * platform-dependant, known keywords as NULL, then only declare them as valid
 * if some options are met. Note that if the requested keyword contains an
 * opening parenthesis, everything from this point is ignored.
 */
struct srv_kw *srv_find_kw(const char *kw)
{
	int index;
	const char *kwend;
	struct srv_kw_list *kwl;
	struct srv_kw *ret = NULL;

	kwend = strchr(kw, '(');
	if (!kwend)
		kwend = kw + strlen(kw);

	list_for_each_entry(kwl, &srv_keywords.list, list) {
		for (index = 0; kwl->kw[index].kw != NULL; index++) {
			if ((strncmp(kwl->kw[index].kw, kw, kwend - kw) == 0) &&
			    kwl->kw[index].kw[kwend-kw] == 0) {
				if (kwl->kw[index].parse)
					return &kwl->kw[index]; /* found it !*/
				else
					ret = &kwl->kw[index];  /* may be OK */
			}
		}
	}
	return ret;
}

/* Dumps all registered "server" keywords to the <out> string pointer. The
 * unsupported keywords are only dumped if their supported form was not
 * found.
 */
void srv_dump_kws(char **out)
{
	struct srv_kw_list *kwl;
	int index;

	if (!out)
		return;

	*out = NULL;
	list_for_each_entry(kwl, &srv_keywords.list, list) {
		for (index = 0; kwl->kw[index].kw != NULL; index++) {
			if (kwl->kw[index].parse ||
			    srv_find_kw(kwl->kw[index].kw) == &kwl->kw[index]) {
				memprintf(out, "%s[%4s] %s%s%s%s\n", *out ? *out : "",
				          kwl->scope,
				          kwl->kw[index].kw,
				          kwl->kw[index].skip ? " <arg>" : "",
				          kwl->kw[index].default_ok ? " [dflt_ok]" : "",
				          kwl->kw[index].parse ? "" : " (not supported)");
			}
		}
	}
}

/* Try to find in srv_keyword the word that looks closest to <word> by counting
 * transitions between letters, digits and other characters. Will return the
 * best matching word if found, otherwise NULL. An optional array of extra
 * words to compare may be passed in <extra>, but it must then be terminated
 * by a NULL entry. If unused it may be NULL.
 */
static const char *srv_find_best_kw(const char *word)
{
	uint8_t word_sig[1024];
	uint8_t list_sig[1024];
	const struct srv_kw_list *kwl;
	const char *best_ptr = NULL;
	int dist, best_dist = INT_MAX;
	const char **extra;
	int index;

	make_word_fingerprint(word_sig, word);
	list_for_each_entry(kwl, &srv_keywords.list, list) {
		for (index = 0; kwl->kw[index].kw != NULL; index++) {
			make_word_fingerprint(list_sig, kwl->kw[index].kw);
			dist = word_fingerprint_distance(word_sig, list_sig);
			if (dist < best_dist) {
				best_dist = dist;
				best_ptr = kwl->kw[index].kw;
			}
		}
	}

	for (extra = extra_kw_list; *extra; extra++) {
		make_word_fingerprint(list_sig, *extra);
		dist = word_fingerprint_distance(word_sig, list_sig);
		if (dist < best_dist) {
			best_dist = dist;
			best_ptr = *extra;
		}
	}

	if (best_dist > 2 * strlen(word) || (best_ptr && best_dist > 2 * strlen(best_ptr)))
		best_ptr = NULL;

	return best_ptr;
}

/* Parse the "backup" server keyword */
static int srv_parse_backup(char **args, int *cur_arg,
                            struct proxy *curproxy, struct server *newsrv, char **err)
{
	newsrv->flags |= SRV_F_BACKUP;
	return 0;
}


/* Parse the "cookie" server keyword */
static int srv_parse_cookie(char **args, int *cur_arg,
                            struct proxy *curproxy, struct server *newsrv, char **err)
{
	char *arg;

	arg = args[*cur_arg + 1];
	if (!*arg) {
		memprintf(err, "'%s' expects <value> as argument.\n", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	free(newsrv->cookie);
	newsrv->cookie = strdup(arg);
	newsrv->cklen = strlen(arg);
	newsrv->flags |= SRV_F_COOKIESET;
	return 0;
}

/* Parse the "disabled" server keyword */
static int srv_parse_disabled(char **args, int *cur_arg,
                              struct proxy *curproxy, struct server *newsrv, char **err)
{
	newsrv->next_admin |= SRV_ADMF_CMAINT | SRV_ADMF_FMAINT;
	newsrv->next_state = SRV_ST_STOPPED;
	newsrv->check.state |= CHK_ST_PAUSED;
	newsrv->check.health = 0;
	return 0;
}

/* Parse the "enabled" server keyword */
static int srv_parse_enabled(char **args, int *cur_arg,
                             struct proxy *curproxy, struct server *newsrv, char **err)
{
	newsrv->next_admin &= ~SRV_ADMF_CMAINT & ~SRV_ADMF_FMAINT;
	newsrv->next_state = SRV_ST_RUNNING;
	newsrv->check.state &= ~CHK_ST_PAUSED;
	newsrv->check.health = newsrv->check.rise;
	return 0;
}

/* Parse the "error-limit" server keyword */
static int srv_parse_error_limit(char **args, int *cur_arg,
                                 struct proxy *curproxy, struct server *newsrv, char **err)
{
	if (!*args[*cur_arg + 1]) {
		memprintf(err, "'%s' expects an integer argument.",
		          args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	newsrv->consecutive_errors_limit = atoi(args[*cur_arg + 1]);

	if (newsrv->consecutive_errors_limit <= 0) {
		memprintf(err, "%s has to be > 0.",
		          args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	return 0;
}

/* Parse the "guid" keyword */
static int srv_parse_guid(char **args, int *cur_arg,
                        struct proxy *curproxy, struct server *newsrv, char **err)
{
	const char *guid;
	char *guid_err = NULL;

	if (!*args[*cur_arg + 1]) {
		memprintf(err, "'%s' : expects an argument", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	guid = args[*cur_arg + 1];
	if (guid_insert(&newsrv->obj_type, guid, &guid_err)) {
		memprintf(err, "'%s': %s", args[*cur_arg], guid_err);
		ha_free(&guid_err);
		return ERR_ALERT | ERR_FATAL;
	}

	return 0;
}

/* Parse the "ws" keyword */
static int srv_parse_ws(char **args, int *cur_arg,
                        struct proxy *curproxy, struct server *newsrv, char **err)
{
	if (!args[*cur_arg + 1]) {
		memprintf(err, "'%s' expects 'auto', 'h1' or 'h2' value", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	if (strcmp(args[*cur_arg + 1], "h1") == 0) {
		newsrv->ws = SRV_WS_H1;
	}
	else if (strcmp(args[*cur_arg + 1], "h2") == 0) {
		newsrv->ws = SRV_WS_H2;
	}
	else if (strcmp(args[*cur_arg + 1], "auto") == 0) {
		newsrv->ws = SRV_WS_AUTO;
	}
	else {
		memprintf(err, "'%s' has to be 'auto', 'h1' or 'h2'", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}


	return 0;
}

/* Parse the "hash-key" server keyword */
static int srv_parse_hash_key(char **args, int *cur_arg,
			      struct proxy *curproxy, struct server *newsrv, char **err)
{
	if (!args[*cur_arg + 1]) {
		memprintf(err, "'%s expects 'id', 'addr', or 'addr-port' value", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	if (strcmp(args[*cur_arg + 1], "id") == 0) {
		newsrv->hash_key = SRV_HASH_KEY_ID;
	}
	else if (strcmp(args[*cur_arg + 1], "addr") == 0) {
		newsrv->hash_key = SRV_HASH_KEY_ADDR;
	}
	else if (strcmp(args[*cur_arg + 1], "addr-port") == 0) {
		newsrv->hash_key = SRV_HASH_KEY_ADDR_PORT;
	}
	else {
		memprintf(err, "'%s' has to be 'id', 'addr', or 'addr-port'", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	return 0;
}

/* Parse the "init-addr" server keyword */
static int srv_parse_init_addr(char **args, int *cur_arg,
                               struct proxy *curproxy, struct server *newsrv, char **err)
{
	char *p, *end;
	int done;
	struct sockaddr_storage sa;

	newsrv->init_addr_methods = 0;
	memset(&newsrv->init_addr, 0, sizeof(newsrv->init_addr));

	for (p = args[*cur_arg + 1]; *p; p = end) {
		/* cut on next comma */
		for (end = p; *end && *end != ','; end++);
		if (*end)
			*(end++) = 0;

		memset(&sa, 0, sizeof(sa));
		if (strcmp(p, "libc") == 0) {
			done = srv_append_initaddr(&newsrv->init_addr_methods, SRV_IADDR_LIBC);
		}
		else if (strcmp(p, "last") == 0) {
			done = srv_append_initaddr(&newsrv->init_addr_methods, SRV_IADDR_LAST);
		}
		else if (strcmp(p, "none") == 0) {
			done = srv_append_initaddr(&newsrv->init_addr_methods, SRV_IADDR_NONE);
		}
		else if (str2ip2(p, &sa, 0)) {
			if (is_addr(&newsrv->init_addr)) {
				memprintf(err, "'%s' : initial address already specified, cannot add '%s'.",
				          args[*cur_arg], p);
				return ERR_ALERT | ERR_FATAL;
			}
			newsrv->init_addr = sa;
			done = srv_append_initaddr(&newsrv->init_addr_methods, SRV_IADDR_IP);
		}
		else {
			memprintf(err, "'%s' : unknown init-addr method '%s', supported methods are 'libc', 'last', 'none'.",
			          args[*cur_arg], p);
			return ERR_ALERT | ERR_FATAL;
		}
		if (!done) {
			memprintf(err, "'%s' : too many init-addr methods when trying to add '%s'",
			          args[*cur_arg], p);
			return ERR_ALERT | ERR_FATAL;
		}
	}

	return 0;
}

/* Parse the "log-bufsize" server keyword */
static int srv_parse_log_bufsize(char **args, int *cur_arg,
                                 struct proxy *curproxy, struct server *newsrv, char **err)
{
	if (!*args[*cur_arg + 1]) {
		memprintf(err, "'%s' expects an integer argument.",
		          args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	newsrv->log_bufsize = atoi(args[*cur_arg + 1]);

	if (newsrv->log_bufsize <= 0) {
		memprintf(err, "%s has to be > 0.",
		          args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	return 0;
}

/* Parse the "log-proto" server keyword */
static int srv_parse_log_proto(char **args, int *cur_arg,
                               struct proxy *curproxy, struct server *newsrv, char **err)
{
	if (strcmp(args[*cur_arg + 1], "legacy") == 0)
		newsrv->log_proto = SRV_LOG_PROTO_LEGACY;
	else if (strcmp(args[*cur_arg + 1], "octet-count") == 0)
		newsrv->log_proto = SRV_LOG_PROTO_OCTET_COUNTING;
	else {
		memprintf(err, "'%s' expects one of 'legacy' or 'octet-count' but got '%s'",
		          args[*cur_arg], args[*cur_arg + 1]);
		return ERR_ALERT | ERR_FATAL;
	}

	return 0;
}

/* Parse the "maxconn" server keyword */
static int srv_parse_maxconn(char **args, int *cur_arg,
                             struct proxy *curproxy, struct server *newsrv, char **err)
{
	newsrv->maxconn = atol(args[*cur_arg + 1]);
	return 0;
}

/* Parse the "maxqueue" server keyword */
static int srv_parse_maxqueue(char **args, int *cur_arg,
                              struct proxy *curproxy, struct server *newsrv, char **err)
{
	newsrv->maxqueue = atol(args[*cur_arg + 1]);
	return 0;
}

/* Parse the "minconn" server keyword */
static int srv_parse_minconn(char **args, int *cur_arg,
                             struct proxy *curproxy, struct server *newsrv, char **err)
{
	newsrv->minconn = atol(args[*cur_arg + 1]);
	return 0;
}

static int srv_parse_max_reuse(char **args, int *cur_arg, struct proxy *curproxy, struct server *newsrv, char **err)
{
	char *arg;

	arg = args[*cur_arg + 1];
	if (!*arg) {
		memprintf(err, "'%s' expects <value> as argument.\n", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}
	newsrv->max_reuse = atoi(arg);

	return 0;
}

static int srv_parse_pool_purge_delay(char **args, int *cur_arg, struct proxy *curproxy, struct server *newsrv, char **err)
{
	const char *res;
	char *arg;
	unsigned int time;

	arg = args[*cur_arg + 1];
	if (!*arg) {
		memprintf(err, "'%s' expects <value> as argument.\n", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}
	res = parse_time_err(arg, &time, TIME_UNIT_MS);
	if (res == PARSE_TIME_OVER) {
		memprintf(err, "timer overflow in argument '%s' to '%s' (maximum value is 2147483647 ms or ~24.8 days)",
			  args[*cur_arg+1], args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}
	else if (res == PARSE_TIME_UNDER) {
		memprintf(err, "timer underflow in argument '%s' to '%s' (minimum non-null value is 1 ms)",
			  args[*cur_arg+1], args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}
	else if (res) {
		memprintf(err, "unexpected character '%c' in argument to <%s>.\n",
		    *res, args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}
	newsrv->pool_purge_delay = time;

	return 0;
}

static int srv_parse_pool_conn_name(char **args, int *cur_arg, struct proxy *curproxy, struct server *newsrv, char **err)
{
	char *arg;

	arg = args[*cur_arg + 1];
	if (!*arg) {
		memprintf(err, "'%s' expects <value> as argument", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	ha_free(&newsrv->pool_conn_name);
	newsrv->pool_conn_name = strdup(arg);
	if (!newsrv->pool_conn_name) {
		memprintf(err, "'%s' : out of memory", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	return 0;
}

static int srv_parse_pool_low_conn(char **args, int *cur_arg, struct proxy *curproxy, struct server *newsrv, char **err)
{
	char *arg;

	arg = args[*cur_arg + 1];
	if (!*arg) {
		memprintf(err, "'%s' expects <value> as argument.\n", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	newsrv->low_idle_conns = atoi(arg);
	return 0;
}

static int srv_parse_pool_max_conn(char **args, int *cur_arg, struct proxy *curproxy, struct server *newsrv, char **err)
{
	char *arg;

	arg = args[*cur_arg + 1];
	if (!*arg) {
		memprintf(err, "'%s' expects <value> as argument.\n", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	newsrv->max_idle_conns = atoi(arg);
	if ((int)newsrv->max_idle_conns < -1) {
		memprintf(err, "'%s' must be >= -1", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	return 0;
}

/* parse the "id" server keyword */
static int srv_parse_id(char **args, int *cur_arg, struct proxy *curproxy, struct server *newsrv, char **err)
{
	struct eb32_node *node;

	if (!*args[*cur_arg + 1]) {
		memprintf(err, "'%s' : expects an integer argument", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	newsrv->puid = atol(args[*cur_arg + 1]);
	newsrv->conf.id.key = newsrv->puid;

	if (newsrv->puid <= 0) {
		memprintf(err, "'%s' : custom id has to be > 0", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	node = eb32_lookup(&curproxy->conf.used_server_id, newsrv->puid);
	if (node) {
		struct server *target = container_of(node, struct server, conf.id);
		memprintf(err, "'%s' : custom id %d already used at %s:%d ('server %s')",
		          args[*cur_arg], newsrv->puid, target->conf.file, target->conf.line,
		          target->id);
		return ERR_ALERT | ERR_FATAL;
	}

	newsrv->flags |= SRV_F_FORCED_ID;
	return 0;
}

/* Parse the "namespace" server keyword */
static int srv_parse_namespace(char **args, int *cur_arg,
                               struct proxy *curproxy, struct server *newsrv, char **err)
{
#ifdef USE_NS
	char *arg;

	arg = args[*cur_arg + 1];
	if (!*arg) {
		memprintf(err, "'%s' : expects <name> as argument", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	if (strcmp(arg, "*") == 0) {
		/* Use the namespace associated with the connection (if present). */
		newsrv->flags |= SRV_F_USE_NS_FROM_PP;
		global.last_checks |= LSTCHK_SYSADM;
		return 0;
	}

	/*
	 * As this parser may be called several times for the same 'default-server'
	 * object, or for a new 'server' instance deriving from a 'default-server'
	 * one with SRV_F_USE_NS_FROM_PP flag enabled, let's reset it.
	 */
	newsrv->flags &= ~SRV_F_USE_NS_FROM_PP;

	newsrv->netns = netns_store_lookup(arg, strlen(arg));
	if (!newsrv->netns)
		newsrv->netns = netns_store_insert(arg);

	if (!newsrv->netns) {
		memprintf(err, "Cannot open namespace '%s'", arg);
		return ERR_ALERT | ERR_FATAL;
	}
	global.last_checks |= LSTCHK_SYSADM;

	return 0;
#else
	memprintf(err, "'%s': '%s' option not implemented", args[0], args[*cur_arg]);
	return ERR_ALERT | ERR_FATAL;
#endif
}

/* Parse the "no-backup" server keyword */
static int srv_parse_no_backup(char **args, int *cur_arg,
                               struct proxy *curproxy, struct server *newsrv, char **err)
{
	newsrv->flags &= ~SRV_F_BACKUP;
	return 0;
}


/* Disable server PROXY protocol flags. */
static inline int srv_disable_pp_flags(struct server *srv, unsigned int flags)
{
	srv->pp_opts &= ~flags;
	return 0;
}

/* Parse the "no-send-proxy" server keyword */
static int srv_parse_no_send_proxy(char **args, int *cur_arg,
                                   struct proxy *curproxy, struct server *newsrv, char **err)
{
	return srv_disable_pp_flags(newsrv, SRV_PP_V1);
}

/* Parse the "no-send-proxy-v2" server keyword */
static int srv_parse_no_send_proxy_v2(char **args, int *cur_arg,
                                      struct proxy *curproxy, struct server *newsrv, char **err)
{
	return srv_disable_pp_flags(newsrv, SRV_PP_V2);
}

/* Parse the "shard" server keyword */
static int srv_parse_shard(char **args, int *cur_arg,
                           struct proxy *curproxy, struct server *newsrv, char **err)
{
	newsrv->shard = atol(args[*cur_arg + 1]);
	return 0;
}

/* Parse the "no-tfo" server keyword */
static int srv_parse_no_tfo(char **args, int *cur_arg,
                            struct proxy *curproxy, struct server *newsrv, char **err)
{
	newsrv->flags &= ~SRV_F_FASTOPEN;
	return 0;
}

/* Parse the "non-stick" server keyword */
static int srv_parse_non_stick(char **args, int *cur_arg,
                               struct proxy *curproxy, struct server *newsrv, char **err)
{
	newsrv->flags |= SRV_F_NON_STICK;
	return 0;
}

/* Enable server PROXY protocol flags. */
static inline int srv_enable_pp_flags(struct server *srv, unsigned int flags)
{
	srv->pp_opts |= flags;
	return 0;
}
/* parse the "proto" server keyword */
static int srv_parse_proto(char **args, int *cur_arg,
			   struct proxy *px, struct server *newsrv, char **err)
{
	struct ist proto;

	if (!*args[*cur_arg + 1]) {
		memprintf(err, "'%s' : missing value", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}
	proto = ist(args[*cur_arg + 1]);
	newsrv->mux_proto = get_mux_proto(proto);
	if (!newsrv->mux_proto) {
		memprintf(err, "'%s' :  unknown MUX protocol '%s'", args[*cur_arg], args[*cur_arg+1]);
		return ERR_ALERT | ERR_FATAL;
	}
	return 0;
}

/* parse the "proxy-v2-options" */
static int srv_parse_proxy_v2_options(char **args, int *cur_arg,
				      struct proxy *px, struct server *newsrv, char **err)
{
	char *p, *n;
	for (p = args[*cur_arg+1]; p; p = n) {
		n = strchr(p, ',');
		if (n)
			*n++ = '\0';
		if (strcmp(p, "ssl") == 0) {
			newsrv->pp_opts |= SRV_PP_V2_SSL;
		} else if (strcmp(p, "cert-cn") == 0) {
			newsrv->pp_opts |= SRV_PP_V2_SSL;
			newsrv->pp_opts |= SRV_PP_V2_SSL_CN;
		} else if (strcmp(p, "cert-key") == 0) {
			newsrv->pp_opts |= SRV_PP_V2_SSL;
			newsrv->pp_opts |= SRV_PP_V2_SSL_KEY_ALG;
		} else if (strcmp(p, "cert-sig") == 0) {
			newsrv->pp_opts |= SRV_PP_V2_SSL;
			newsrv->pp_opts |= SRV_PP_V2_SSL_SIG_ALG;
		} else if (strcmp(p, "ssl-cipher") == 0) {
			newsrv->pp_opts |= SRV_PP_V2_SSL;
			newsrv->pp_opts |= SRV_PP_V2_SSL_CIPHER;
		} else if (strcmp(p, "authority") == 0) {
			newsrv->pp_opts |= SRV_PP_V2_AUTHORITY;
		} else if (strcmp(p, "crc32c") == 0) {
			newsrv->pp_opts |= SRV_PP_V2_CRC32C;
		} else if (strcmp(p, "unique-id") == 0) {
			newsrv->pp_opts |= SRV_PP_V2_UNIQUE_ID;
		} else
			goto fail;
	}
	return 0;
 fail:
	if (err)
		memprintf(err, "'%s' : proxy v2 option not implemented", p);
	return ERR_ALERT | ERR_FATAL;
}

/* Parse the "observe" server keyword */
static int srv_parse_observe(char **args, int *cur_arg,
                             struct proxy *curproxy, struct server *newsrv, char **err)
{
	char *arg;

	arg = args[*cur_arg + 1];
	if (!*arg) {
		memprintf(err, "'%s' expects <mode> as argument.\n", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	if (strcmp(arg, "none") == 0) {
		newsrv->observe = HANA_OBS_NONE;
	}
	else if (strcmp(arg, "layer4") == 0) {
		newsrv->observe = HANA_OBS_LAYER4;
	}
	else if (strcmp(arg, "layer7") == 0) {
		if (curproxy->mode != PR_MODE_HTTP) {
			memprintf(err, "'%s' can only be used in http proxies.\n", arg);
			return ERR_ALERT;
		}
		newsrv->observe = HANA_OBS_LAYER7;
	}
	else {
		memprintf(err, "'%s' expects one of 'none', 'layer4', 'layer7' "
		               "but got '%s'\n", args[*cur_arg], arg);
		return ERR_ALERT | ERR_FATAL;
	}

	return 0;
}

/* Parse the "on-error" server keyword */
static int srv_parse_on_error(char **args, int *cur_arg,
                              struct proxy *curproxy, struct server *newsrv, char **err)
{
	if (strcmp(args[*cur_arg + 1], "fastinter") == 0)
		newsrv->onerror = HANA_ONERR_FASTINTER;
	else if (strcmp(args[*cur_arg + 1], "fail-check") == 0)
		newsrv->onerror = HANA_ONERR_FAILCHK;
	else if (strcmp(args[*cur_arg + 1], "sudden-death") == 0)
		newsrv->onerror = HANA_ONERR_SUDDTH;
	else if (strcmp(args[*cur_arg + 1], "mark-down") == 0)
		newsrv->onerror = HANA_ONERR_MARKDWN;
	else {
		memprintf(err, "'%s' expects one of 'fastinter', "
		          "'fail-check', 'sudden-death' or 'mark-down' but got '%s'",
		          args[*cur_arg], args[*cur_arg + 1]);
		return ERR_ALERT | ERR_FATAL;
	}

	return 0;
}

/* Parse the "on-marked-down" server keyword */
static int srv_parse_on_marked_down(char **args, int *cur_arg,
                                    struct proxy *curproxy, struct server *newsrv, char **err)
{
	if (strcmp(args[*cur_arg + 1], "shutdown-sessions") == 0)
		newsrv->onmarkeddown = HANA_ONMARKEDDOWN_SHUTDOWNSESSIONS;
	else {
		memprintf(err, "'%s' expects 'shutdown-sessions' but got '%s'",
		          args[*cur_arg], args[*cur_arg + 1]);
		return ERR_ALERT | ERR_FATAL;
	}

	return 0;
}

/* Parse the "on-marked-up" server keyword */
static int srv_parse_on_marked_up(char **args, int *cur_arg,
                                  struct proxy *curproxy, struct server *newsrv, char **err)
{
	if (strcmp(args[*cur_arg + 1], "shutdown-backup-sessions") == 0)
		newsrv->onmarkedup = HANA_ONMARKEDUP_SHUTDOWNBACKUPSESSIONS;
	else {
		memprintf(err, "'%s' expects 'shutdown-backup-sessions' but got '%s'",
		          args[*cur_arg], args[*cur_arg + 1]);
		return ERR_ALERT | ERR_FATAL;
	}

	return 0;
}

/* Parse the "redir" server keyword */
static int srv_parse_redir(char **args, int *cur_arg,
                           struct proxy *curproxy, struct server *newsrv, char **err)
{
	char *arg;

	arg = args[*cur_arg + 1];
	if (!*arg) {
		memprintf(err, "'%s' expects <prefix> as argument.\n", args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	free(newsrv->rdr_pfx);
	newsrv->rdr_pfx = strdup(arg);
	newsrv->rdr_len = strlen(arg);

	return 0;
}

/* Parse the "resolvers" server keyword */
static int srv_parse_resolvers(char **args, int *cur_arg,
                           struct proxy *curproxy, struct server *newsrv, char **err)
{
	free(newsrv->resolvers_id);
	newsrv->resolvers_id = strdup(args[*cur_arg + 1]);
	return 0;
}

/* Parse the "resolve-net" server keyword */
static int srv_parse_resolve_net(char **args, int *cur_arg,
                                 struct proxy *curproxy, struct server *newsrv, char **err)
{
	char *p, *e;
	unsigned char mask;
	struct resolv_options *opt;

	if (!args[*cur_arg + 1] || args[*cur_arg + 1][0] == '\0') {
		memprintf(err, "'%s' expects a list of networks.",
		          args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	opt = &newsrv->resolv_opts;

	/* Split arguments by comma, and convert it from ipv4 or ipv6
	 * string network in in_addr or in6_addr.
	 */
	p = args[*cur_arg + 1];
	e = p;
	while (*p != '\0') {
		/* If no room available, return error. */
		if (opt->pref_net_nb >= SRV_MAX_PREF_NET) {
			memprintf(err, "'%s' exceed %d networks.",
			          args[*cur_arg], SRV_MAX_PREF_NET);
			return ERR_ALERT | ERR_FATAL;
		}
		/* look for end or comma. */
		while (*e != ',' && *e != '\0')
			e++;
		if (*e == ',') {
			*e = '\0';
			e++;
		}
		if (str2net(p, 0, &opt->pref_net[opt->pref_net_nb].addr.in4,
		                  &opt->pref_net[opt->pref_net_nb].mask.in4)) {
			/* Try to convert input string from ipv4 or ipv6 network. */
			opt->pref_net[opt->pref_net_nb].family = AF_INET;
		} else if (str62net(p, &opt->pref_net[opt->pref_net_nb].addr.in6,
		                     &mask)) {
			/* Try to convert input string from ipv6 network. */
			len2mask6(mask, &opt->pref_net[opt->pref_net_nb].mask.in6);
			opt->pref_net[opt->pref_net_nb].family = AF_INET6;
		} else {
			/* All network conversions fail, return error. */
			memprintf(err, "'%s' invalid network '%s'.",
			          args[*cur_arg], p);
			return ERR_ALERT | ERR_FATAL;
		}
		opt->pref_net_nb++;
		p = e;
	}

	return 0;
}

/* Parse the "resolve-opts" server keyword */
static int srv_parse_resolve_opts(char **args, int *cur_arg,
                                  struct proxy *curproxy, struct server *newsrv, char **err)
{
	char *p, *end;

	for (p = args[*cur_arg + 1]; *p; p = end) {
		/* cut on next comma */
		for (end = p; *end && *end != ','; end++);
		if (*end)
			*(end++) = 0;

		if (strcmp(p, "allow-dup-ip") == 0) {
			newsrv->resolv_opts.accept_duplicate_ip = 1;
		}
		else if (strcmp(p, "ignore-weight") == 0) {
			newsrv->resolv_opts.ignore_weight = 1;
		}
		else if (strcmp(p, "prevent-dup-ip") == 0) {
			newsrv->resolv_opts.accept_duplicate_ip = 0;
		}
		else {
			memprintf(err, "'%s' : unknown resolve-opts option '%s', supported methods are 'allow-dup-ip', 'ignore-weight', and 'prevent-dup-ip'.",
			          args[*cur_arg], p);
			return ERR_ALERT | ERR_FATAL;
		}
	}

	return 0;
}

/* Parse the "resolve-prefer" server keyword */
static int srv_parse_resolve_prefer(char **args, int *cur_arg,
                                    struct proxy *curproxy, struct server *newsrv, char **err)
{
	if (strcmp(args[*cur_arg + 1], "ipv4") == 0)
		newsrv->resolv_opts.family_prio = AF_INET;
	else if (strcmp(args[*cur_arg + 1], "ipv6") == 0)
		newsrv->resolv_opts.family_prio = AF_INET6;
	else {
		memprintf(err, "'%s' expects either ipv4 or ipv6 as argument.",
		          args[*cur_arg]);
		return ERR_ALERT | ERR_FATAL;
	}

	return 0;
}

/* Parse the "send-proxy" server keyword */
static int srv_parse_send_proxy(char **args, int *cur_arg,
                                struct proxy *curproxy, struct server *newsrv, char **err)
{
	return srv_enable_pp_flags(newsrv, SRV_PP_V1);
}

/* Parse the "send-proxy-v2" server keyword */
static int srv_parse_send_proxy_v2(char **args, int *cur_arg,
                                   struct proxy *curproxy, struct server *newsrv, char **err)
{
	return srv_enable_pp_flags(newsrv, SRV_PP_V2);
}

/* Parse the "set-proxy-v2-tlv-fmt" server keyword */
static int srv_parse_set_proxy_v2_tlv_fmt(char **args, int *cur_arg,
                                   struct proxy *px, struct server *newsrv, char **err)
{
	char *error = NULL, *cmd = NULL;
	unsigned int  tlv_type = 0;
	struct srv_pp_tlv_list *srv_tlv = NULL;

	cmd = args[*cur_arg];
	if (!*cmd) {
		memprintf(err, "'%s' : could not read set-proxy-v2-tlv-fmt command", args[*cur_arg]);
		goto fail;
	}

	cmd += strlen("set-proxy-v2-tlv-fmt");

	if (*cmd == '(') {
		cmd++; /* skip the '(' */
		errno = 0;
		tlv_type = strtoul(cmd, &error, 0); /* convert TLV ID */
		if (unlikely((cmd == error) || (errno != 0))) {
			memprintf(err, "'%s' : could not convert TLV ID", args[*cur_arg]);
			goto fail;
		}
		if (errno == EINVAL) {
			memprintf(err, "'%s' : could not find a valid number for the TLV ID", args[*cur_arg]);
			goto fail;
		}
		if (*error != ')') {
			memprintf(err, "'%s' : expects set-proxy-v2-tlv(<TLV ID>)", args[*cur_arg]);
			goto fail;
		}
		if (tlv_type > 0xFF) {
			memprintf(err, "'%s' : the maximum allowed TLV ID is %d", args[*cur_arg], 0xFF);
			goto fail;
		}
	}

	srv_tlv = malloc(sizeof(*srv_tlv));
	if (unlikely(!srv_tlv)) {
		memprintf(err, "'%s' : failed to parse allocate TLV entry", args[*cur_arg]);
		goto fail;
	}
	srv_tlv->type = tlv_type;
	srv_tlv->fmt_string = strdup(args[*cur_arg + 1]);
	if (unlikely(!srv_tlv->fmt_string)) {
		memprintf(err, "'%s' : failed to save format string for parsing", args[*cur_arg]);
		goto fail;
	}

	LIST_APPEND(&newsrv->pp_tlvs, &srv_tlv->list);

	(*cur_arg)++;

	return 0;

 fail:
	free(srv_tlv);
	errno = 0;
	return ERR_ALERT | ERR_FATAL;
}

/* Parse the "slowstart" server keyword */
static int srv_parse_slowstart(char **args, int *cur_arg,
                               struct proxy *curproxy, struct server *newsrv, char **err)
{
	/* slowstart is stored in seconds */
	unsigned int val;
	const char *time_err = parse_time_err(args[*cur_arg + 1], &val, TIME_UNIT_MS);

	if (time_err == PARSE_TIME_OVER) {
		memprintf(err, "overflow in argument <%s> to <%s> of server %s, maximum value is 2147483647 ms (~24.8 days).",
		          args[*cur_arg+1], args[*cur_arg], newsrv->id);
		return ERR_ALERT | ERR_FATAL;
	}
	else if (time_err == PARSE_TIME_UNDER) {
		memprintf(err, "underflow in argument <%s> to <%s> of server %s, minimum non-null value is 1 ms.",
		          args[*cur_arg+1], args[*cur_arg], newsrv->id);
		return ERR_ALERT | ERR_FATAL;
	}
	else if (time_err) {
		memprintf(err, "unexpected character '%c' in 'slowstart' argument of server %s.",
		          *time_err, newsrv->id);
		return ERR_ALERT | ERR_FATAL;
	}
	newsrv->slowstart = (val + 999) / 1000;

	return 0;
}

/* Parse the "source" server keyword */
static int srv_parse_source(char **args, int *cur_arg,
                            struct proxy *curproxy, struct server *newsrv, char **err)
{
	char *errmsg;
	int port_low, port_high;
	struct sockaddr_storage *sk;

	errmsg = NULL;

	if (!*args[*cur_arg + 1]) {
		memprintf(err, "'%s' expects <addr>[:<port>[-<port>]], and optionally '%s' <addr>, "
		               "and '%s' <name> as argument.\n", args[*cur_arg], "usesrc", "interface");
		goto err;
	}

	/* 'sk' is statically allocated (no need to be freed). */
	sk = str2sa_range(args[*cur_arg + 1], NULL, &port_low, &port_high, NULL, NULL, NULL,
	                  &errmsg, NULL, NULL,
		          PA_O_RESOLVE | PA_O_PORT_OK | PA_O_PORT_RANGE | PA_O_STREAM | PA_O_CONNECT);
	if (!sk) {
		memprintf(err, "'%s %s' : %s\n", args[*cur_arg], args[*cur_arg + 1], errmsg);
		goto err;
	}

	newsrv->conn_src.opts |= CO_SRC_BIND;
	newsrv->conn_src.source_addr = *sk;

	if (port_low != port_high) {
		int i;

		newsrv->conn_src.sport_range = port_range_alloc_range(port_high - port_low + 1);
		if (!newsrv->conn_src.sport_range) {
			ha_alert("Server '%s': Out of memory (sport_range)\n", args[0]);
			goto err;
		}
		for (i = 0; i < newsrv->conn_src.sport_range->size; i++)
			newsrv->conn_src.sport_range->ports[i] = port_low + i;
	}

	*cur_arg += 2;
	while (*(args[*cur_arg])) {
		if (strcmp(args[*cur_arg], "usesrc") == 0) {  /* address to use outside */
#if defined(CONFIG_HAP_TRANSPARENT)
			if (!*args[*cur_arg + 1]) {
				ha_alert("'usesrc' expects <addr>[:<port>], 'client', 'clientip', "
					 "or 'hdr_ip(name,#)' as argument.\n");
				goto err;
			}
			if (strcmp(args[*cur_arg + 1], "client") == 0) {
				newsrv->conn_src.opts &= ~CO_SRC_TPROXY_MASK;
				newsrv->conn_src.opts |= CO_SRC_TPROXY_CLI;
			}
			else if (strcmp(args[*cur_arg + 1], "clientip") == 0) {
				newsrv->conn_src.opts &= ~CO_SRC_TPROXY_MASK;
				newsrv->conn_src.opts |= CO_SRC_TPROXY_CIP;
			}
			else if (!strncmp(args[*cur_arg + 1], "hdr_ip(", 7)) {
				char *name, *end;

				name = args[*cur_arg + 1] + 7;
				while (isspace((unsigned char)*name))
					name++;

				end = name;
				while (*end && !isspace((unsigned char)*end) && *end != ',' && *end != ')')
					end++;

				newsrv->conn_src.opts &= ~CO_SRC_TPROXY_MASK;
				newsrv->conn_src.opts |= CO_SRC_TPROXY_DYN;
				free(newsrv->conn_src.bind_hdr_name);
				newsrv->conn_src.bind_hdr_name = calloc(1, end - name + 1);
				if (!newsrv->conn_src.bind_hdr_name) {
					ha_alert("Server '%s': Out of memory (bind_hdr_name)\n", args[0]);
					goto err;
				}
				newsrv->conn_src.bind_hdr_len = end - name;
				memcpy(newsrv->conn_src.bind_hdr_name, name, end - name);
				newsrv->conn_src.bind_hdr_name[end - name] = '\0';
				newsrv->conn_src.bind_hdr_occ = -1;

				/* now look for an occurrence number */
				while (isspace((unsigned char)*end))
					end++;
				if (*end == ',') {
					end++;
					name = end;
					if (*end == '-')
						end++;
					while (isdigit((unsigned char)*end))
						end++;
					newsrv->conn_src.bind_hdr_occ = strl2ic(name, end - name);
				}

				if (newsrv->conn_src.bind_hdr_occ < -MAX_HDR_HISTORY) {
					ha_alert("usesrc hdr_ip(name,num) does not support negative"
						 " occurrences values smaller than %d.\n", MAX_HDR_HISTORY);
					goto err;
				}
			}
			else {
				struct sockaddr_storage *sk;
				int port1, port2;

				/* 'sk' is statically allocated (no need to be freed). */
				sk = str2sa_range(args[*cur_arg + 1], NULL, &port1, &port2, NULL, NULL, NULL,
				                  &errmsg, NULL, NULL,
				                  PA_O_RESOLVE | PA_O_PORT_OK | PA_O_STREAM | PA_O_CONNECT);
				if (!sk) {
					ha_alert("'%s %s' : %s\n", args[*cur_arg], args[*cur_arg + 1], errmsg);
					goto err;
				}

				newsrv->conn_src.tproxy_addr = *sk;
				newsrv->conn_src.opts |= CO_SRC_TPROXY_ADDR;
			}
			global.last_checks |= LSTCHK_NETADM;
			*cur_arg += 2;
			continue;
#else	/* no TPROXY support */
			ha_alert("'usesrc' not allowed here because support for TPROXY was not compiled in.\n");
			goto err;
#endif /* defined(CONFIG_HAP_TRANSPARENT) */
		} /* "usesrc" */

		if (strcmp(args[*cur_arg], "interface") == 0) { /* specifically bind to this interface */
#ifdef SO_BINDTODEVICE
			if (!*args[*cur_arg + 1]) {
				ha_alert("'%s' : missing interface name.\n", args[0]);
				goto err;
			}
			free(newsrv->conn_src.iface_name);
			newsrv->conn_src.iface_name = strdup(args[*cur_arg + 1]);
			newsrv->conn_src.iface_len  = strlen(newsrv->conn_src.iface_name);
			global.last_checks |= LSTCHK_NETADM;
#else
			ha_alert("'%s' : '%s' option not implemented.\n", args[0], args[*cur_arg]);
			goto err;
#endif
			*cur_arg += 2;
			continue;
		}
		/* this keyword in not an option of "source" */
		break;
	} /* while */

	return 0;

 err:
	free(errmsg);
	return ERR_ALERT | ERR_FATAL;
}

/* Parse the "stick" server keyword */
static int srv_parse_stick(char **args, int *cur_arg,
                           struct proxy *curproxy, struct server *newsrv, char **err)
{
	newsrv->flags &= ~SRV_F_NON_STICK;
	return 0;
}

/* Parse the "track" server keyword */
static int srv_parse_track(char **args, int *cur_arg,
                           struct proxy *curproxy, struct server *newsrv, char **err)
{
	char *arg;

	arg = args[*cur_arg + 1];
	if (!*arg) {
		memprintf(err, "'track' expects [<proxy>/]<server> as argument.\n");
		return ERR_ALERT | ERR_FATAL;
	}

	free(newsrv->trackit);
	newsrv->trackit = strdup(arg);

	return 0;
}

/* Parse the "socks4" server keyword */
static int srv_parse_socks4(char **args, int *cur_arg,
                            struct proxy *curproxy, struct server *newsrv, char **err)
{
	char *errmsg;
	int port_low, port_high;
	struct sockaddr_storage *sk;

	errmsg = NULL;

	if (!*args[*cur_arg + 1]) {
		memprintf(err, "'%s' expects <addr>:<port> as argument.\n", args[*cur_arg]);
		goto err;
	}

	/* 'sk' is statically allocated (no need to be freed). */
	sk = str2sa_range(args[*cur_arg + 1], NULL, &port_low, &port_high, NULL, NULL, NULL,
	                  &errmsg, NULL, NULL,
	                  PA_O_RESOLVE | PA_O_PORT_OK | PA_O_PORT_MAND | PA_O_STREAM | PA_O_CONNECT);
	if (!sk) {
		memprintf(err, "'%s %s' : %s\n", args[*cur_arg], args[*cur_arg + 1], errmsg);
		goto err;
	}

	newsrv->flags |= SRV_F_SOCKS4_PROXY;
	newsrv->socks4_addr = *sk;

	return 0;

 err:
	free(errmsg);
	return ERR_ALERT | ERR_FATAL;
}


/* parse the "tfo" server keyword */
static int srv_parse_tfo(char **args, int *cur_arg, struct proxy *px, struct server *newsrv, char **err)
{
	newsrv->flags |= SRV_F_FASTOPEN;
	return 0;
}

/* parse the "usesrc" server keyword */
static int srv_parse_usesrc(char **args, int *cur_arg, struct proxy *px, struct server *newsrv, char **err)
{
	memprintf(err, "'%s' only allowed after a '%s' statement.",
	          "usesrc", "source");
	return ERR_ALERT | ERR_FATAL;
}

/* parse the "weight" server keyword */
static int srv_parse_weight(char **args, int *cur_arg, struct proxy *px, struct server *newsrv, char **err)
{
	int w;

	w = atol(args[*cur_arg + 1]);
	if (w < 0 || w > SRV_UWGHT_MAX) {
		memprintf(err, "weight of server %s is not within 0 and %d (%d).",
		          newsrv->id, SRV_UWGHT_MAX, w);
		return ERR_ALERT | ERR_FATAL;
	}
	newsrv->uweight = newsrv->iweight = w;

	return 0;
}

/* Returns 1 if the server has streams pointing to it, and 0 otherwise.
 *
 * Must be called with the server lock held.
 */
static int srv_has_streams(struct server *srv)
{
	int thr;

	for (thr = 0; thr < global.nbthread; thr++)
		if (!MT_LIST_ISEMPTY(&srv->per_thr[thr].streams))
			return 1;
	return 0;
}

/* Shutdown all connections of a server. The caller must pass a termination
 * code in <why>, which must be one of SF_ERR_* indicating the reason for the
 * shutdown.
 *
 * Must be called with the server lock held.
 */
void srv_shutdown_streams(struct server *srv, int why)
{
	struct stream *stream;
	struct mt_list *elt1, elt2;
	int thr;

	for (thr = 0; thr < global.nbthread; thr++)
		mt_list_for_each_entry_safe(stream, &srv->per_thr[thr].streams, by_srv, elt1, elt2)
			if (stream->srv_conn == srv)
				stream_shutdown(stream, why);
}

/* Shutdown all connections of all backup servers of a proxy. The caller must
 * pass a termination code in <why>, which must be one of SF_ERR_* indicating
 * the reason for the shutdown.
 *
 * Must be called with the server lock held.
 */
void srv_shutdown_backup_streams(struct proxy *px, int why)
{
	struct server *srv;

	for (srv = px->srv; srv != NULL; srv = srv->next)
		if (srv->flags & SRV_F_BACKUP)
			srv_shutdown_streams(srv, why);
}

static void srv_append_op_chg_cause(struct buffer *msg, struct server *s, enum srv_op_st_chg_cause cause)
{
	switch (cause) {
		case SRV_OP_STCHGC_NONE:
			break; /* do nothing */
		case SRV_OP_STCHGC_HEALTH:
			check_append_info(msg, &s->check);
			break;
		case SRV_OP_STCHGC_AGENT:
			check_append_info(msg, &s->agent);
			break;
		default:
			chunk_appendf(msg, ", %s", srv_op_st_chg_cause(cause));
			break;
	}
}

static void srv_append_adm_chg_cause(struct buffer *msg, struct server *s, enum srv_adm_st_chg_cause cause)
{
	if (cause)
		chunk_appendf(msg, " (%s)", srv_adm_st_chg_cause(cause));
}

/* Appends some information to a message string related to a server tracking
 * or requeued connections info.
 *
 * If <forced> is null and the server tracks another one, a "via"
 * If <xferred> is non-negative, some information about requeued sessions are
 * provided.
 *
 * Must be called with the server lock held.
 */
static void srv_append_more(struct buffer *msg, struct server *s,
                            int xferred, int forced)
{
	if (!forced && s->track) {
		chunk_appendf(msg, " via %s/%s", s->track->proxy->id, s->track->id);
	}

	if (xferred >= 0) {
		if (s->next_state == SRV_ST_STOPPED)
			chunk_appendf(msg, ". %d active and %d backup servers left.%s"
				" %d sessions active, %d requeued, %d remaining in queue",
				s->proxy->srv_act, s->proxy->srv_bck,
				(s->proxy->srv_bck && !s->proxy->srv_act) ? " Running on backup." : "",
				s->cur_sess, xferred, s->queue.length);
		else
			chunk_appendf(msg, ". %d active and %d backup servers online.%s"
				" %d sessions requeued, %d total in queue",
				s->proxy->srv_act, s->proxy->srv_bck,
				(s->proxy->srv_bck && !s->proxy->srv_act) ? " Running on backup." : "",
				xferred, s->queue.length);
	}
}

/* Marks server <s> down, regardless of its checks' statuses. The server
 * transfers queued streams whenever possible to other servers at a sync
 * point. Maintenance servers are ignored.
 *
 * Must be called with the server lock held.
 */
void srv_set_stopped(struct server *s, enum srv_op_st_chg_cause cause)
{
	struct server *srv;

	if ((s->cur_admin & SRV_ADMF_MAINT) || s->next_state == SRV_ST_STOPPED)
		return;

	s->next_state = SRV_ST_STOPPED;

	/* propagate changes */
	srv_update_status(s, 0, cause);

	for (srv = s->trackers; srv; srv = srv->tracknext) {
		HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);
		srv_set_stopped(srv, SRV_OP_STCHGC_NONE);
		HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
	}
}

/* Marks server <s> up regardless of its checks' statuses and provided it isn't
 * in maintenance. The server tries to grab requests from the proxy at a sync
 * point. Maintenance servers are ignored.
 *
 * Must be called with the server lock held.
 */
void srv_set_running(struct server *s, enum srv_op_st_chg_cause cause)
{
	struct server *srv;

	if (s->cur_admin & SRV_ADMF_MAINT)
		return;

	if (s->next_state == SRV_ST_STARTING || s->next_state == SRV_ST_RUNNING)
		return;

	s->next_state = SRV_ST_STARTING;

	if (s->slowstart <= 0)
		s->next_state = SRV_ST_RUNNING;

	/* propagate changes */
	srv_update_status(s, 0, cause);

	for (srv = s->trackers; srv; srv = srv->tracknext) {
		HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);
		srv_set_running(srv, SRV_OP_STCHGC_NONE);
		HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
	}
}

/* Marks server <s> stopping regardless of its checks' statuses and provided it
 * isn't in maintenance. The server tries to redispatch pending requests
 * to the proxy. Maintenance servers are ignored.
 *
 * Must be called with the server lock held.
 */
void srv_set_stopping(struct server *s, enum srv_op_st_chg_cause cause)
{
	struct server *srv;

	if (s->cur_admin & SRV_ADMF_MAINT)
		return;

	if (s->next_state == SRV_ST_STOPPING)
		return;

	s->next_state = SRV_ST_STOPPING;

	/* propagate changes */
	srv_update_status(s, 0, cause);

	for (srv = s->trackers; srv; srv = srv->tracknext) {
		HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);
		srv_set_stopping(srv, SRV_OP_STCHGC_NONE);
		HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
	}
}

/* Enables admin flag <mode> (among SRV_ADMF_*) on server <s>. This is used to
 * enforce either maint mode or drain mode. It is not allowed to set more than
 * one flag at once. The equivalent "inherited" flag is propagated to all
 * tracking servers. Maintenance mode disables health checks (but not agent
 * checks). When either the flag is already set or no flag is passed, nothing
 * is done. If <cause> is non-null, it will be displayed at the end of the log
 * lines to justify the state change.
 *
 * Must be called with the server lock held.
 */
void srv_set_admin_flag(struct server *s, enum srv_admin mode, enum srv_adm_st_chg_cause cause)
{
	struct server *srv;

	if (!mode)
		return;

	/* stop going down as soon as we meet a server already in the same state */
	if (s->next_admin & mode)
		return;

	s->next_admin |= mode;

	/* propagate changes */
	srv_update_status(s, 1, cause);

	/* stop going down if the equivalent flag was already present (forced or inherited) */
	if (((mode & SRV_ADMF_MAINT) && (s->next_admin & ~mode & SRV_ADMF_MAINT)) ||
	    ((mode & SRV_ADMF_DRAIN) && (s->next_admin & ~mode & SRV_ADMF_DRAIN)))
		return;

	/* compute the inherited flag to propagate */
	if (mode & SRV_ADMF_MAINT)
		mode = SRV_ADMF_IMAINT;
	else if (mode & SRV_ADMF_DRAIN)
		mode = SRV_ADMF_IDRAIN;

	for (srv = s->trackers; srv; srv = srv->tracknext) {
		HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);
		srv_set_admin_flag(srv, mode, cause);
		HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
	}
}

/* Disables admin flag <mode> (among SRV_ADMF_*) on server <s>. This is used to
 * stop enforcing either maint mode or drain mode. It is not allowed to set more
 * than one flag at once. The equivalent "inherited" flag is propagated to all
 * tracking servers. Leaving maintenance mode re-enables health checks. When
 * either the flag is already cleared or no flag is passed, nothing is done.
 *
 * Must be called with the server lock held.
 */
void srv_clr_admin_flag(struct server *s, enum srv_admin mode)
{
	struct server *srv;

	if (!mode)
		return;

	/* stop going down as soon as we see the flag is not there anymore */
	if (!(s->next_admin & mode))
		return;

	s->next_admin &= ~mode;

	/* propagate changes */
	srv_update_status(s, 1, SRV_ADM_STCHGC_NONE);

	/* stop going down if the equivalent flag is still present (forced or inherited) */
	if (((mode & SRV_ADMF_MAINT) && (s->next_admin & SRV_ADMF_MAINT)) ||
	    ((mode & SRV_ADMF_DRAIN) && (s->next_admin & SRV_ADMF_DRAIN)))
		return;

	if (mode & SRV_ADMF_MAINT)
		mode = SRV_ADMF_IMAINT;
	else if (mode & SRV_ADMF_DRAIN)
		mode = SRV_ADMF_IDRAIN;

	for (srv = s->trackers; srv; srv = srv->tracknext) {
		HA_SPIN_LOCK(SERVER_LOCK, &srv->lock);
		srv_clr_admin_flag(srv, mode);
		HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
	}
}

/* principle: propagate maint and drain to tracking servers. This is useful
 * upon startup so that inherited states are correct.
 */
static void srv_propagate_admin_state(struct server *srv)
{
	struct server *srv2;

	if (!srv->trackers)
		return;

	for (srv2 = srv->trackers; srv2; srv2 = srv2->tracknext) {
		HA_SPIN_LOCK(SERVER_LOCK, &srv2->lock);
		if (srv->next_admin & (SRV_ADMF_MAINT | SRV_ADMF_CMAINT))
			srv_set_admin_flag(srv2, SRV_ADMF_IMAINT, SRV_ADM_STCHGC_NONE);

		if (srv->next_admin & SRV_ADMF_DRAIN)
			srv_set_admin_flag(srv2, SRV_ADMF_IDRAIN, SRV_ADM_STCHGC_NONE);
		HA_SPIN_UNLOCK(SERVER_LOCK, &srv2->lock);
	}
}

/* Compute and propagate the admin states for all servers in proxy <px>.
 * Only servers *not* tracking another one are considered, because other
 * ones will be handled when the server they track is visited.
 */
void srv_compute_all_admin_states(struct proxy *px)
{
	struct server *srv;

	for (srv = px->srv; srv; srv = srv->next) {
		if (srv->track)
			continue;
		srv_propagate_admin_state(srv);
	}
}

/* Note: must not be declared <const> as its list will be overwritten.
 * Please take care of keeping this list alphabetically sorted, doing so helps
 * all code contributors.
 * Optional keywords are also declared with a NULL ->parse() function so that
 * the config parser can report an appropriate error when a known keyword was
 * not enabled.
 * Note: -1 as ->skip value means that the number of arguments are variable.
 */
static struct srv_kw_list srv_kws = { "ALL", { }, {
	{ "backup",               srv_parse_backup,               0,  1,  1 }, /* Flag as backup server */
	{ "cookie",               srv_parse_cookie,               1,  1,  1 }, /* Assign a cookie to the server */
	{ "disabled",             srv_parse_disabled,             0,  1,  1 }, /* Start the server in 'disabled' state */
	{ "enabled",              srv_parse_enabled,              0,  1,  0 }, /* Start the server in 'enabled' state */
	{ "error-limit",          srv_parse_error_limit,          1,  1,  1 }, /* Configure the consecutive count of check failures to consider a server on error */
	{ "guid",                 srv_parse_guid,                 1,  0,  1 }, /* Set global unique ID of the server */
	{ "ws",                   srv_parse_ws,                   1,  1,  1 }, /* websocket protocol */
	{ "hash-key",             srv_parse_hash_key,             1,  1,  1 }, /* Configure how chash keys are computed */
	{ "id",                   srv_parse_id,                   1,  0,  1 }, /* set id# of server */
	{ "init-addr",            srv_parse_init_addr,            1,  1,  0 }, /* */
	{ "log-bufsize",          srv_parse_log_bufsize,          1,  1,  0 }, /* Set the ring bufsize for log server (only for log backends) */
	{ "log-proto",            srv_parse_log_proto,            1,  1,  0 }, /* Set the protocol for event messages, only relevant in a log or ring section */
	{ "maxconn",              srv_parse_maxconn,              1,  1,  1 }, /* Set the max number of concurrent connection */
	{ "maxqueue",             srv_parse_maxqueue,             1,  1,  1 }, /* Set the max number of connection to put in queue */
	{ "max-reuse",            srv_parse_max_reuse,            1,  1,  0 }, /* Set the max number of requests on a connection, -1 means unlimited */
	{ "minconn",              srv_parse_minconn,              1,  1,  1 }, /* Enable a dynamic maxconn limit */
	{ "namespace",            srv_parse_namespace,            1,  1,  0 }, /* Namespace the server socket belongs to (if supported) */
	{ "no-backup",            srv_parse_no_backup,            0,  1,  1 }, /* Flag as non-backup server */
	{ "no-send-proxy",        srv_parse_no_send_proxy,        0,  1,  1 }, /* Disable use of PROXY V1 protocol */
	{ "no-send-proxy-v2",     srv_parse_no_send_proxy_v2,     0,  1,  1 }, /* Disable use of PROXY V2 protocol */
	{ "no-tfo",               srv_parse_no_tfo,               0,  1,  1 }, /* Disable use of TCP Fast Open */
	{ "non-stick",            srv_parse_non_stick,            0,  1,  0 }, /* Disable stick-table persistence */
	{ "observe",              srv_parse_observe,              1,  1,  1 }, /* Enables health adjusting based on observing communication with the server */
	{ "on-error",             srv_parse_on_error,             1,  1,  1 }, /* Configure the action on check failure */
	{ "on-marked-down",       srv_parse_on_marked_down,       1,  1,  1 }, /* Configure the action when a server is marked down */
	{ "on-marked-up",         srv_parse_on_marked_up,         1,  1,  1 }, /* Configure the action when a server is marked up */
	{ "pool-conn-name",       srv_parse_pool_conn_name,       1,  1,  1 }, /* Define expression to identify connections in idle pool */
	{ "pool-low-conn",        srv_parse_pool_low_conn,        1,  1,  1 }, /* Set the min number of orphan idle connecbefore being allowed to pick from other threads */
	{ "pool-max-conn",        srv_parse_pool_max_conn,        1,  1,  1 }, /* Set the max number of orphan idle connections, -1 means unlimited */
	{ "pool-purge-delay",     srv_parse_pool_purge_delay,     1,  1,  1 }, /* Set the time before we destroy orphan idle connections, defaults to 1s */
	{ "proto",                srv_parse_proto,                1,  1,  1 }, /* Set the proto to use for all outgoing connections */
	{ "proxy-v2-options",     srv_parse_proxy_v2_options,     1,  1,  1 }, /* options for send-proxy-v2 */
	{ "redir",                srv_parse_redir,                1,  1,  0 }, /* Enable redirection mode */
	{ "resolve-net",          srv_parse_resolve_net,          1,  1,  0 }, /* Set the preferred network range for name resolution */
	{ "resolve-opts",         srv_parse_resolve_opts,         1,  1,  0 }, /* Set options for name resolution */
	{ "resolve-prefer",       srv_parse_resolve_prefer,       1,  1,  0 }, /* Set the preferred family for name resolution */
	{ "resolvers",            srv_parse_resolvers,            1,  1,  0 }, /* Configure the resolver to use for name resolution */
	{ "send-proxy",           srv_parse_send_proxy,           0,  1,  1 }, /* Enforce use of PROXY V1 protocol */
	{ "send-proxy-v2",        srv_parse_send_proxy_v2,        0,  1,  1 }, /* Enforce use of PROXY V2 protocol */
	{ "set-proxy-v2-tlv-fmt", srv_parse_set_proxy_v2_tlv_fmt, 0,  1,  1 }, /* Set TLV of PROXY V2 protocol */
	{ "shard",                srv_parse_shard,                1,  1,  1 }, /* Server shard (only in peers protocol context) */
	{ "slowstart",            srv_parse_slowstart,            1,  1,  1 }, /* Set the warm-up timer for a previously failed server */
	{ "source",               srv_parse_source,              -1,  1,  1 }, /* Set the source address to be used to connect to the server */
	{ "stick",                srv_parse_stick,                0,  1,  0 }, /* Enable stick-table persistence */
	{ "tfo",                  srv_parse_tfo,                  0,  1,  1 }, /* enable TCP Fast Open of server */
	{ "track",                srv_parse_track,                1,  1,  1 }, /* Set the current state of the server, tracking another one */
	{ "socks4",               srv_parse_socks4,               1,  1,  0 }, /* Set the socks4 proxy of the server*/
	{ "usesrc",               srv_parse_usesrc,               0,  1,  1 }, /* safe-guard against usesrc without preceding <source> keyword */
	{ "weight",               srv_parse_weight,               1,  1,  1 }, /* Set the load-balancing weight */
	{ NULL, NULL, 0 },
}};

INITCALL1(STG_REGISTER, srv_register_keywords, &srv_kws);

/* Recomputes the server's eweight based on its state, uweight, the current time,
 * and the proxy's algorithm. To be used after updating sv->uweight. The warmup
 * state is automatically disabled if the time is elapsed. If <must_update> is
 * not zero, the update will be propagated immediately.
 *
 * Must be called with the server lock held.
 */
void server_recalc_eweight(struct server *sv, int must_update)
{
	struct proxy *px = sv->proxy;
	unsigned w;

	if (ns_to_sec(now_ns) < sv->counters.last_change || ns_to_sec(now_ns) >= sv->counters.last_change + sv->slowstart) {
		/* go to full throttle if the slowstart interval is reached unless server is currently down */
		if ((sv->cur_state != SRV_ST_STOPPED) && (sv->next_state == SRV_ST_STARTING))
			sv->next_state = SRV_ST_RUNNING;
	}

	/* We must take care of not pushing the server to full throttle during slow starts.
	 * It must also start immediately, at least at the minimal step when leaving maintenance.
	 */
	if ((sv->cur_state == SRV_ST_STOPPED) && (sv->next_state == SRV_ST_STARTING) && (px->lbprm.algo & BE_LB_PROP_DYN))
		w = 1;
	else if ((sv->next_state == SRV_ST_STARTING) && (px->lbprm.algo & BE_LB_PROP_DYN))
		w = (px->lbprm.wdiv * (ns_to_sec(now_ns) - sv->counters.last_change) + sv->slowstart) / sv->slowstart;
	else
		w = px->lbprm.wdiv;

	sv->next_eweight = (sv->uweight * w + px->lbprm.wmult - 1) / px->lbprm.wmult;

	/* propagate changes only if needed (i.e. not recursively) */
	if (must_update)
		srv_update_status(sv, 0, SRV_OP_STCHGC_NONE);
}

/*
 * Parses weight_str and configures sv accordingly.
 * Returns NULL on success, error message string otherwise.
 *
 * Must be called with the server lock held.
 */
const char *server_parse_weight_change_request(struct server *sv,
					       const char *weight_str)
{
	struct proxy *px;
	long int w;
	char *end;

	px = sv->proxy;

	/* if the weight is terminated with '%', it is set relative to
	 * the initial weight, otherwise it is absolute.
	 */
	if (!*weight_str)
		return "Require <weight> or <weight%>.\n";

	w = strtol(weight_str, &end, 10);
	if (end == weight_str)
		return "Empty weight string empty or preceded by garbage\n";
	else if (end[0] == '%' && end[1] == '\0') {
		if (w < 0)
			return "Relative weight must be positive.\n";
		/* Avoid integer overflow */
		if (w > 25600)
			w = 25600;
		w = sv->iweight * w / 100;
		if (w > 256)
			w = 256;
	}
	else if (w < 0 || w > 256)
		return "Absolute weight can only be between 0 and 256 inclusive.\n";
	else if (end[0] != '\0')
		return "Trailing garbage in weight string\n";

	if (w && w != sv->iweight && !(px->lbprm.algo & BE_LB_PROP_DYN))
		return "Backend is using a static LB algorithm and only accepts weights '0%' and '100%'.\n";

	sv->uweight = w;
	server_recalc_eweight(sv, 1);

	return NULL;
}

/*
 * Must be called with the server lock held.
 */
const char *server_parse_maxconn_change_request(struct server *sv,
                                                const char *maxconn_str)
{
	long int v;
	char *end;

	if (!*maxconn_str)
		return "Require <maxconn>.\n";

	v = strtol(maxconn_str, &end, 10);
	if (end == maxconn_str)
		return "maxconn string empty or preceded by garbage\n";
	else if (end[0] != '\0')
		return "Trailing garbage in maxconn string\n";

	if (sv->maxconn == sv->minconn) { // static maxconn
		sv->maxconn = sv->minconn = v;
	} else { // dynamic maxconn
		sv->maxconn = v;
	}

	if (may_dequeue_tasks(sv, sv->proxy))
		process_srv_queue(sv);

	return NULL;
}

/* Interpret <expr> as sample expression. This function is reserved for
 * internal server allocation. On parsing use parse_srv_expr() for extra sample
 * check validity.
 *
 * Returns the allocated sample on success or NULL on error.
 */
struct sample_expr *_parse_srv_expr(char *expr, struct arg_list *args_px,
                                    const char *file, int linenum, char **err)
{
	int idx;
	const char *args[] = {
		expr,
		NULL,
	};

	idx = 0;
	args_px->ctx = ARGC_SRV;

	return sample_parse_expr((char **)args, &idx, file, linenum, err, args_px, NULL);
}

/* Interpret <str> if not empty as a sample expression and store it into <out>.
 * Contrary to _parse_srv_expr(), fetch scope validity is checked to ensure it
 * is valid on a server line context. It also updates <px> HTTP mode
 * requirement depending on fetch method used.
 *
 * Returns 0 on success else non zero.
 */
static int parse_srv_expr(char *str, struct sample_expr **out, struct proxy *px,
                          char **err)
{
	struct sample_expr *expr;

	if (!str)
		return 0;

	expr = _parse_srv_expr(str, &px->conf.args, px->conf.file, px->conf.line, err);
	if (!expr)
		return ERR_ALERT | ERR_FATAL;

	if (!(expr->fetch->val & SMP_VAL_BE_SRV_CON)) {
		memprintf(err, "fetch method '%s' extracts information from '%s', "
		          "none of which is available here.",
		          str, sample_src_names(expr->fetch->use));
		return ERR_ALERT | ERR_FATAL;
	}

	px->http_needed |= !!(expr->fetch->use & SMP_USE_HTTP_ANY);
	release_sample_expr(*out);
	*out = expr;

	return 0;
}

static void display_parser_err(const char *file, int linenum, char **args, int cur_arg, int err_code, char **err)
{
	char *msg = "error encountered while processing ";
	char *quote = "'";
	char *token = args[cur_arg];

	if (err && *err) {
		indent_msg(err, 2);
		msg = *err;
		quote = "";
		token = "";
	}

	if (err_code & ERR_WARN && !(err_code & ERR_ALERT))
		ha_warning("%s%s%s%s.\n", msg, quote, token, quote);
	else
		ha_alert("%s%s%s%s.\n", msg, quote, token, quote);
}

static void srv_conn_src_sport_range_cpy(struct server *srv, const struct server *src)
{
	int range_sz;

	range_sz = src->conn_src.sport_range->size;
	if (range_sz > 0) {
		srv->conn_src.sport_range = port_range_alloc_range(range_sz);
		if (srv->conn_src.sport_range != NULL) {
			int i;

			for (i = 0; i < range_sz; i++) {
				srv->conn_src.sport_range->ports[i] =
					src->conn_src.sport_range->ports[i];
			}
		}
	}
}

/*
 * Copy <src> server connection source settings to <srv> server everything needed.
 */
static void srv_conn_src_cpy(struct server *srv, const struct server *src)
{
	srv->conn_src.opts = src->conn_src.opts;
	srv->conn_src.source_addr = src->conn_src.source_addr;

	/* Source port range copy. */
	if (src->conn_src.sport_range != NULL)
		srv_conn_src_sport_range_cpy(srv, src);

#ifdef CONFIG_HAP_TRANSPARENT
	if (src->conn_src.bind_hdr_name != NULL) {
		srv->conn_src.bind_hdr_name = strdup(src->conn_src.bind_hdr_name);
		srv->conn_src.bind_hdr_len = strlen(src->conn_src.bind_hdr_name);
	}
	srv->conn_src.bind_hdr_occ = src->conn_src.bind_hdr_occ;
	srv->conn_src.tproxy_addr  = src->conn_src.tproxy_addr;
#endif
	if (src->conn_src.iface_name != NULL) {
		srv->conn_src.iface_name = strdup(src->conn_src.iface_name);
		srv->conn_src.iface_len = src->conn_src.iface_len;
	}
}

/*
 * Copy <src> server SSL settings to <srv> server allocating
 * everything needed.
 */
#if defined(USE_OPENSSL)
static void srv_ssl_settings_cpy(struct server *srv, const struct server *src)
{
	/* <src> is the current proxy's default server and SSL is enabled */
	BUG_ON(src->ssl_ctx.ctx != NULL); /* the SSL_CTX must never be initialized in a default-server */

	if (src == &srv->proxy->defsrv && src->use_ssl == 1)
		srv->flags |= SRV_F_DEFSRV_USE_SSL;

	if (src->ssl_ctx.ca_file != NULL)
		srv->ssl_ctx.ca_file = strdup(src->ssl_ctx.ca_file);
	if (src->ssl_ctx.crl_file != NULL)
		srv->ssl_ctx.crl_file = strdup(src->ssl_ctx.crl_file);
	if (src->ssl_ctx.client_crt != NULL)
		srv->ssl_ctx.client_crt = strdup(src->ssl_ctx.client_crt);

	srv->ssl_ctx.verify = src->ssl_ctx.verify;


	if (src->ssl_ctx.verify_host != NULL)
		srv->ssl_ctx.verify_host = strdup(src->ssl_ctx.verify_host);
	if (src->ssl_ctx.ciphers != NULL)
		srv->ssl_ctx.ciphers = strdup(src->ssl_ctx.ciphers);
	if (src->ssl_ctx.options)
		srv->ssl_ctx.options = src->ssl_ctx.options;
	if (src->ssl_ctx.methods.flags)
		srv->ssl_ctx.methods.flags = src->ssl_ctx.methods.flags;
	if (src->ssl_ctx.methods.min)
		srv->ssl_ctx.methods.min = src->ssl_ctx.methods.min;
	if (src->ssl_ctx.methods.max)
		srv->ssl_ctx.methods.max = src->ssl_ctx.methods.max;

	if (src->ssl_ctx.ciphersuites != NULL)
		srv->ssl_ctx.ciphersuites = strdup(src->ssl_ctx.ciphersuites);
	if (src->sni_expr != NULL)
		srv->sni_expr = strdup(src->sni_expr);

	if (src->ssl_ctx.alpn_str) {
		srv->ssl_ctx.alpn_str = malloc(src->ssl_ctx.alpn_len);
		if (srv->ssl_ctx.alpn_str) {
			memcpy(srv->ssl_ctx.alpn_str, src->ssl_ctx.alpn_str,
			    src->ssl_ctx.alpn_len);
			srv->ssl_ctx.alpn_len = src->ssl_ctx.alpn_len;
		}
	}

	if (src->ssl_ctx.npn_str) {
		srv->ssl_ctx.npn_str = malloc(src->ssl_ctx.npn_len);
		if (srv->ssl_ctx.npn_str) {
			memcpy(srv->ssl_ctx.npn_str, src->ssl_ctx.npn_str,
			    src->ssl_ctx.npn_len);
			srv->ssl_ctx.npn_len = src->ssl_ctx.npn_len;
		}
	}
}

/* Activate ssl on server <s>.
 * do nothing if there is no change to apply
 *
 * Must be called with the server lock held.
 */
void srv_set_ssl(struct server *s, int use_ssl)
{
	if (s->use_ssl == use_ssl)
		return;

	s->use_ssl = use_ssl;
	if (s->use_ssl)
		s->xprt = xprt_get(XPRT_SSL);
	else
		s->xprt = xprt_get(XPRT_RAW);
}

#endif /* USE_OPENSSL */

/*
 * Prepare <srv> for hostname resolution.
 * May be safely called with a default server as <src> argument (without hostname).
 * Returns -1 in case of any allocation failure, 0 if not.
 */
int srv_prepare_for_resolution(struct server *srv, const char *hostname)
{
	char *hostname_dn;
	int   hostname_len, hostname_dn_len;

	if (!hostname)
		return 0;

	hostname_len    = strlen(hostname);
	hostname_dn     = trash.area;
	hostname_dn_len = resolv_str_to_dn_label(hostname, hostname_len,
	                                         hostname_dn, trash.size);
	if (hostname_dn_len == -1)
		goto err;


	free(srv->hostname);
	free(srv->hostname_dn);
	srv->hostname        = strdup(hostname);
	srv->hostname_dn     = strdup(hostname_dn);
	srv->hostname_dn_len = hostname_dn_len;
	if (!srv->hostname || !srv->hostname_dn)
		goto err;

	return 0;

 err:
	ha_free(&srv->hostname);
	ha_free(&srv->hostname_dn);
	return -1;
}

/* Initialize default values for <srv>. Used both for dynamic servers and
 * default servers. The latter are not initialized via new_server(), hence this
 * function purpose. For static servers, srv_settings_cpy() is used instead
 * reusing their default server instance.
 */
void srv_settings_init(struct server *srv)
{
	srv->check.inter = DEF_CHKINTR;
	srv->check.fastinter = 0;
	srv->check.downinter = 0;
	srv->check.rise = DEF_RISETIME;
	srv->check.fall = DEF_FALLTIME;
	srv->check.port = 0;

	srv->agent.inter = DEF_CHKINTR;
	srv->agent.fastinter = 0;
	srv->agent.downinter = 0;
	srv->agent.rise = DEF_AGENT_RISETIME;
	srv->agent.fall = DEF_AGENT_FALLTIME;
	srv->agent.port = 0;

	srv->maxqueue = 0;
	srv->minconn = 0;
	srv->maxconn = 0;

	srv->max_reuse = -1;
	srv->max_idle_conns = -1;
	srv->pool_purge_delay = 5000;

	srv->slowstart = 0;

	srv->onerror = DEF_HANA_ONERR;
	srv->consecutive_errors_limit = DEF_HANA_ERRLIMIT;

	srv->uweight = srv->iweight = 1;

	LIST_INIT(&srv->pp_tlvs);
}

/*
 * Copy <src> server settings to <srv> server allocating
 * everything needed.
 * This function is not supposed to be called at any time, but only
 * during server settings parsing or during server allocations from
 * a server template, and just after having calloc()'ed a new server.
 * So, <src> may only be a default server (when parsing server settings)
 * or a server template (during server allocations from a server template).
 * <srv_tmpl> distinguishes these two cases (must be 1 if <srv> is a template,
 * 0 if not).
 */
void srv_settings_cpy(struct server *srv, const struct server *src, int srv_tmpl)
{
	struct srv_pp_tlv_list *srv_tlv = NULL, *new_srv_tlv = NULL;

	/* Connection source settings copy */
	srv_conn_src_cpy(srv, src);

	if (srv_tmpl) {
		srv->addr = src->addr;
		srv->addr_type = src->addr_type;
		srv->svc_port = src->svc_port;
	}

	srv->pp_opts = src->pp_opts;
	if (src->rdr_pfx != NULL) {
		srv->rdr_pfx = strdup(src->rdr_pfx);
		srv->rdr_len = src->rdr_len;
	}
	if (src->cookie != NULL) {
		srv->cookie = strdup(src->cookie);
		srv->cklen  = src->cklen;
	}
	srv->use_ssl                  = src->use_ssl;
	srv->check.addr               = src->check.addr;
	srv->agent.addr               = src->agent.addr;
	srv->check.use_ssl            = src->check.use_ssl;
	srv->check.port               = src->check.port;
	srv->check.sni                = src->check.sni;
	srv->check.alpn_str           = src->check.alpn_str;
	srv->check.alpn_len           = src->check.alpn_len;
	/* Note: 'flags' field has potentially been already initialized. */
	srv->flags                   |= src->flags;
	srv->do_check                 = src->do_check;
	srv->do_agent                 = src->do_agent;
	srv->check.inter              = src->check.inter;
	srv->check.fastinter          = src->check.fastinter;
	srv->check.downinter          = src->check.downinter;
	srv->agent.use_ssl            = src->agent.use_ssl;
	srv->agent.port               = src->agent.port;

	if (src->agent.tcpcheck_rules) {
		srv->agent.tcpcheck_rules = calloc(1, sizeof(*srv->agent.tcpcheck_rules));
		if (srv->agent.tcpcheck_rules) {
			srv->agent.tcpcheck_rules->flags = src->agent.tcpcheck_rules->flags;
			srv->agent.tcpcheck_rules->list  = src->agent.tcpcheck_rules->list;
			LIST_INIT(&srv->agent.tcpcheck_rules->preset_vars);
			dup_tcpcheck_vars(&srv->agent.tcpcheck_rules->preset_vars,
					  &src->agent.tcpcheck_rules->preset_vars);
		}
	}

	srv->agent.inter              = src->agent.inter;
	srv->agent.fastinter          = src->agent.fastinter;
	srv->agent.downinter          = src->agent.downinter;
	srv->maxqueue                 = src->maxqueue;
	srv->ws                       = src->ws;
	srv->minconn                  = src->minconn;
	srv->maxconn                  = src->maxconn;
	srv->slowstart                = src->slowstart;
	srv->hash_key                 = src->hash_key;
	srv->observe                  = src->observe;
	srv->onerror                  = src->onerror;
	srv->onmarkeddown             = src->onmarkeddown;
	srv->onmarkedup               = src->onmarkedup;
	if (src->trackit != NULL)
		srv->trackit = strdup(src->trackit);
	srv->consecutive_errors_limit = src->consecutive_errors_limit;
	srv->uweight = srv->iweight   = src->iweight;

	srv->check.send_proxy         = src->check.send_proxy;
	/* health: up, but will fall down at first failure */
	srv->check.rise = srv->check.health = src->check.rise;
	srv->check.fall               = src->check.fall;

	/* Here we check if 'disabled' is the default server state */
	if (src->next_admin & (SRV_ADMF_CMAINT | SRV_ADMF_FMAINT)) {
		srv->next_admin |= SRV_ADMF_CMAINT | SRV_ADMF_FMAINT;
		srv->next_state        = SRV_ST_STOPPED;
		srv->check.state |= CHK_ST_PAUSED;
		srv->check.health = 0;
	}

	/* health: up but will fall down at first failure */
	srv->agent.rise	= srv->agent.health = src->agent.rise;
	srv->agent.fall	              = src->agent.fall;

	if (src->resolvers_id != NULL)
		srv->resolvers_id = strdup(src->resolvers_id);
	srv->resolv_opts.family_prio = src->resolv_opts.family_prio;
	srv->resolv_opts.accept_duplicate_ip = src->resolv_opts.accept_duplicate_ip;
	srv->resolv_opts.ignore_weight = src->resolv_opts.ignore_weight;
	if (srv->resolv_opts.family_prio == AF_UNSPEC)
		srv->resolv_opts.family_prio = AF_INET6;
	memcpy(srv->resolv_opts.pref_net,
	       src->resolv_opts.pref_net,
	       sizeof srv->resolv_opts.pref_net);
	srv->resolv_opts.pref_net_nb  = src->resolv_opts.pref_net_nb;

	srv->init_addr_methods        = src->init_addr_methods;
	srv->init_addr                = src->init_addr;
#if defined(USE_OPENSSL)
	srv_ssl_settings_cpy(srv, src);
#endif
#ifdef TCP_USER_TIMEOUT
	srv->tcp_ut = src->tcp_ut;
#endif
	srv->mux_proto = src->mux_proto;
	if (srv->pool_conn_name)
		srv->pool_conn_name = strdup(srv->pool_conn_name);
	srv->pool_purge_delay = src->pool_purge_delay;
	srv->low_idle_conns = src->low_idle_conns;
	srv->max_idle_conns = src->max_idle_conns;
	srv->max_reuse = src->max_reuse;

	if (srv_tmpl)
		srv->srvrq = src->srvrq;

	srv->netns                    = src->netns;
	srv->check.via_socks4         = src->check.via_socks4;
	srv->socks4_addr              = src->socks4_addr;
	srv->log_bufsize              = src->log_bufsize;

	LIST_INIT(&srv->pp_tlvs);

	list_for_each_entry(srv_tlv, &src->pp_tlvs, list) {
		new_srv_tlv = malloc(sizeof(*new_srv_tlv));
		if (unlikely(!new_srv_tlv)) {
			break;
		}
		new_srv_tlv->fmt_string = strdup(srv_tlv->fmt_string);
		if (unlikely(!new_srv_tlv->fmt_string)) {
			free(new_srv_tlv);
			break;
		}
		new_srv_tlv->type = srv_tlv->type;
		LIST_APPEND(&srv->pp_tlvs, &new_srv_tlv->list);
	}
}

/* allocate a server and attach it to the global servers_list. Returns
 * the server on success, otherwise NULL.
 */
struct server *new_server(struct proxy *proxy)
{
	struct server *srv;

	srv = calloc(1, sizeof *srv);
	if (!srv)
		return NULL;

	srv_take(srv);

	srv->obj_type = OBJ_TYPE_SERVER;
	srv->proxy = proxy;
	queue_init(&srv->queue, proxy, srv);
	LIST_APPEND(&servers_list, &srv->global_list);
	LIST_INIT(&srv->srv_rec_item);
	LIST_INIT(&srv->ip_rec_item);
	LIST_INIT(&srv->pp_tlvs);
	MT_LIST_INIT(&srv->prev_deleted);
	event_hdl_sub_list_init(&srv->e_subs);
	srv->rid = 0; /* rid defaults to 0 */

	srv->next_state = SRV_ST_RUNNING; /* early server setup */
	srv->counters.last_change = ns_to_sec(now_ns);

	srv->check.obj_type = OBJ_TYPE_CHECK;
	srv->check.status = HCHK_STATUS_INI;
	srv->check.server = srv;
	srv->check.proxy = proxy;
	srv->check.tcpcheck_rules = &proxy->tcpcheck_rules;

	srv->agent.obj_type = OBJ_TYPE_CHECK;
	srv->agent.status = HCHK_STATUS_INI;
	srv->agent.server = srv;
	srv->agent.proxy = proxy;
	srv->xprt  = srv->check.xprt = srv->agent.xprt = xprt_get(XPRT_RAW);

	MT_LIST_INIT(&srv->sess_conns);

	guid_init(&srv->guid);

	srv->extra_counters = NULL;
#ifdef USE_OPENSSL
	HA_RWLOCK_INIT(&srv->ssl_ctx.lock);
#endif

	/* please don't put default server settings here, they are set in
	 * proxy_preset_defaults().
	 */
	return srv;
}

/* Increment the server refcount. */
void srv_take(struct server *srv)
{
	HA_ATOMIC_INC(&srv->refcount);
}

/* deallocate common server parameters (may be used by default-servers) */
void srv_free_params(struct server *srv)
{
	struct srv_pp_tlv_list *srv_tlv = NULL;

	free(srv->cookie);
	free(srv->rdr_pfx);
	free(srv->hostname);
	free(srv->hostname_dn);
	free((char*)srv->conf.file);
	free(srv->per_thr);
	free(srv->per_tgrp);
	free(srv->curr_idle_thr);
	free(srv->pool_conn_name);
	release_sample_expr(srv->pool_conn_name_expr);
	free(srv->resolvers_id);
	free(srv->addr_node.key);
	free(srv->lb_nodes);
	if (srv->log_target) {
		deinit_log_target(srv->log_target);
		free(srv->log_target);
	}

	if (xprt_get(XPRT_SSL) && xprt_get(XPRT_SSL)->destroy_srv)
		xprt_get(XPRT_SSL)->destroy_srv(srv);

	while (!LIST_ISEMPTY(&srv->pp_tlvs)) {
		srv_tlv = LIST_ELEM(srv->pp_tlvs.n, struct srv_pp_tlv_list *, list);
		LIST_DEL_INIT(&srv_tlv->list);
		lf_expr_deinit(&srv_tlv->fmt);
		ha_free(&srv_tlv->fmt_string);
		ha_free(&srv_tlv);
	}
}

/* Deallocate a server <srv> and its member. <srv> must be allocated. For
 * dynamic servers, its refcount is decremented first. The free operations are
 * conducted only if the refcount is nul.
 *
 * As a convenience, <srv.next> is returned if srv is not NULL. It may be useful
 * when calling srv_drop on the list of servers.
 */
struct server *srv_drop(struct server *srv)
{
	struct server *next = NULL;

	if (!srv)
		goto end;

	next = srv->next;

	/* For dynamic servers, decrement the reference counter. Only free the
	 * server when reaching zero.
	 */
	if (HA_ATOMIC_SUB_FETCH(&srv->refcount, 1))
		goto end;

	guid_remove(&srv->guid);

	/* make sure we are removed from our 'next->prev_deleted' list
	 * This doesn't require full thread isolation as we're using mt lists
	 * However this could easily be turned into regular list if required
	 * (with the proper use of thread isolation)
	 */
	MT_LIST_DELETE(&srv->prev_deleted);

	task_destroy(srv->warmup);
	task_destroy(srv->srvrq_check);

	free(srv->id);
	srv_free_params(srv);

	HA_SPIN_DESTROY(&srv->lock);

	LIST_DELETE(&srv->global_list);
	event_hdl_sub_list_destroy(&srv->e_subs);

	EXTRA_COUNTERS_FREE(srv->extra_counters);

	ha_free(&srv);

 end:
	return next;
}

/* Detach server from proxy list. It is supported to call this
 * even if the server is not yet in the list
 */
static void _srv_detach(struct server *srv)
{
	struct proxy *be = srv->proxy;

	if (be->srv == srv) {
		be->srv = srv->next;
	}
	else {
		struct server *prev;

		for (prev = be->srv; prev && prev->next != srv; prev = prev->next)
			;
		if (prev)
			prev->next = srv->next;
	}
}

/* Remove a server <srv> from a tracking list if <srv> is tracking another
 * server. No special care is taken if <srv> is tracked itself by another one :
 * this situation should be avoided by the caller.
 *
 * Not thread-safe.
 */
static void release_server_track(struct server *srv)
{
	struct server *strack = srv->track;
	struct server **base;

	if (!strack)
		return;

	for (base = &strack->trackers; *base; base = &((*base)->tracknext)) {
		if (*base == srv) {
			*base = srv->tracknext;
			return;
		}
	}

	/* srv not found on the tracking list, this should never happen */
	BUG_ON(!*base);
}

/*
 * Parse as much as possible such a range string argument: low[-high]
 * Set <nb_low> and <nb_high> values so that they may be reused by this loop
 * for(int i = nb_low; i <= nb_high; i++)... with nb_low >= 1.
 * Fails if 'low' < 0 or 'high' is present and not higher than 'low'.
 * Returns 0 if succeeded, -1 if not.
 */
static int _srv_parse_tmpl_range(struct server *srv, const char *arg,
                                 int *nb_low, int *nb_high)
{
	char *nb_high_arg;

	*nb_high = 0;
	chunk_printf(&trash, "%s", arg);
	*nb_low = atoi(trash.area);

	if ((nb_high_arg = strchr(trash.area, '-'))) {
		*nb_high_arg++ = '\0';
		*nb_high = atoi(nb_high_arg);
	}
	else {
		*nb_high += *nb_low;
		*nb_low = 1;
	}

	if (*nb_low < 0 || *nb_high < *nb_low)
		return -1;

	return 0;
}

/* Parse as much as possible such a range string argument: low[-high]
 * Set <nb_low> and <nb_high> values so that they may be reused by this loop
 * for(int i = nb_low; i <= nb_high; i++)... with nb_low >= 1.
 *
 * This function is first intended to be used through parse_server to
 * initialize a new server on startup.
 *
 * Fails if 'low' < 0 or 'high' is present and not higher than 'low'.
 * Returns 0 if succeeded, -1 if not.
 */
static inline void _srv_parse_set_id_from_prefix(struct server *srv,
                                                 const char *prefix, int nb)
{
	chunk_printf(&trash, "%s%d", prefix, nb);
	free(srv->id);
	srv->id = strdup(trash.area);
}

/* Initialize as much as possible servers from <srv> server template.
 * Note that a server template is a special server with
 * a few different parameters than a server which has
 * been parsed mostly the same way as a server.
 *
 * This function is first intended to be used through parse_server to
 * initialize a new server on startup.
 *
 * Returns the number of servers successfully allocated,
 * 'srv' template included.
 */
static int _srv_parse_tmpl_init(struct server *srv, struct proxy *px)
{
	int i;
	struct server *newsrv;

	/* Set the first server's ID. */
	_srv_parse_set_id_from_prefix(srv, srv->tmpl_info.prefix, srv->tmpl_info.nb_low);
	srv->conf.name.key = srv->id;
	ebis_insert(&curproxy->conf.used_server_name, &srv->conf.name);

	/* then create other servers from this one */
	for (i = srv->tmpl_info.nb_low + 1; i <= srv->tmpl_info.nb_high; i++) {
		newsrv = new_server(px);
		if (!newsrv)
			goto err;

		newsrv->conf.file = strdup(srv->conf.file);
		newsrv->conf.line = srv->conf.line;

		srv_settings_cpy(newsrv, srv, 1);
		srv_prepare_for_resolution(newsrv, srv->hostname);

		/* Use sni as fallback if pool_conn_name isn't set */
		if (!newsrv->pool_conn_name && newsrv->sni_expr) {
			newsrv->pool_conn_name = strdup(newsrv->sni_expr);
			if (!newsrv->pool_conn_name)
				goto err;
		}

		if (newsrv->pool_conn_name) {
			newsrv->pool_conn_name_expr = _parse_srv_expr(srv->pool_conn_name, &px->conf.args, NULL, 0, NULL);
			if (!newsrv->pool_conn_name_expr)
				goto err;
		}

		if (newsrv->sni_expr) {
			newsrv->ssl_ctx.sni = _parse_srv_expr(srv->sni_expr, &px->conf.args, NULL, 0, NULL);
			if (!newsrv->ssl_ctx.sni)
				goto err;
		}

		/* append to list of servers available to receive an hostname */
		if (newsrv->srvrq)
			LIST_APPEND(&newsrv->srvrq->attached_servers, &newsrv->srv_rec_item);

		/* Set this new server ID. */
		_srv_parse_set_id_from_prefix(newsrv, srv->tmpl_info.prefix, i);

		/* Linked backwards first. This will be restablished after parsing. */
		newsrv->next = px->srv;
		px->srv = newsrv;

		newsrv->conf.name.key = newsrv->id;
		ebis_insert(&curproxy->conf.used_server_name, &newsrv->conf.name);
	}
	_srv_parse_set_id_from_prefix(srv, srv->tmpl_info.prefix, srv->tmpl_info.nb_low);

	return i - srv->tmpl_info.nb_low;

 err:
	_srv_parse_set_id_from_prefix(srv, srv->tmpl_info.prefix, srv->tmpl_info.nb_low);
	if (newsrv)  {
		release_sample_expr(newsrv->ssl_ctx.sni);
		free_check(&newsrv->agent);
		free_check(&newsrv->check);
		LIST_DELETE(&newsrv->global_list);
	}
	free(newsrv);
	return i - srv->tmpl_info.nb_low;
}

/* Ensure server config will work with effective proxy mode
 *
 * This function is expected to be called after _srv_parse_init() initialization
 * but only when the effective server's proxy mode is known, which is not always
 * the case during parsing time, in which case the function will be called during
 * postparsing thanks to the _srv_postparse() below.
 *
 * Returns ERR_NONE on success else a combination or ERR_CODE.
 */
static int _srv_check_proxy_mode(struct server *srv, char postparse)
{
	int err_code = ERR_NONE;

	if (postparse && !(srv->proxy->cap & PR_CAP_LB))
		return ERR_NONE; /* nothing to do, the check was already performed during parsing */

	if (srv->conf.file)
		set_usermsgs_ctx(srv->conf.file, srv->conf.line, NULL);

	if (!srv->proxy) {
		/* proxy mode not known, cannot perform checks (ie: defaults section) */
		goto out;
	}

	if (srv->proxy->mode == PR_MODE_SYSLOG) {
		/* log backend server (belongs to proxy with mode log enabled):
		 * perform some compatibility checks
		 */

		/* supported address family types are:
		 *   - ipv4
		 *   - ipv6
		 * (UNSPEC is supported because it means it will be resolved later)
		 */
		if (srv->addr.ss_family != AF_UNSPEC &&
		    srv->addr.ss_family != AF_INET && srv->addr.ss_family != AF_INET6) {
			ha_alert("log server address family not supported for log backend server.\n");
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}

		/* only @tcp or @udp address forms (or equivalent) are supported */
		if (!(srv->addr_type.xprt_type == PROTO_TYPE_DGRAM && srv->addr_type.proto_type == PROTO_TYPE_DGRAM) &&
		    !(srv->addr_type.xprt_type == PROTO_TYPE_STREAM && srv->addr_type.proto_type == PROTO_TYPE_STREAM)) {
			ha_alert("log server address type not supported for log backend server.\n");
			err_code |= ERR_ALERT | ERR_FATAL;
		}
	}
	else {
		/* for all other proxy modes: only TCP expected as srv's transport type for now */
		if (srv->addr_type.xprt_type != PROTO_TYPE_STREAM) {
			ha_alert("unsupported transport for server address in '%s' backend.\n", proxy_mode_str(srv->proxy->mode));
			err_code |= ERR_ALERT | ERR_FATAL;
		}
	}
 out:
	if (srv->conf.file)
		reset_usermsgs_ctx();

	return err_code;
}

/* Perform some server postparsing checks / tasks:
 * We must be careful that checks / postinits performed within this function
 * don't depend or conflict with other postcheck functions that are registered
 * using REGISTER_POST_SERVER_CHECK() hook.
 *
 * Returns ERR_NONE on success else a combination or ERR_CODE.
 */
static int _srv_postparse(struct server *srv)
{
	int err_code = ERR_NONE;

	err_code |= _srv_check_proxy_mode(srv, 1);

	return err_code;
}
REGISTER_POST_SERVER_CHECK(_srv_postparse);

/* Allocate a new server pointed by <srv> and try to parse the first arguments
 * in <args> as an address for a server or an address-range for a template or
 * nothing for a default-server. <cur_arg> is incremented to the next argument.
 *
 * This function is first intended to be used through parse_server to
 * initialize a new server on startup.
 *
 * A mask of errors is returned. On a parsing error, ERR_FATAL is set. In case
 * of memory exhaustion, ERR_ABORT is set. If the server cannot be allocated,
 * <srv> will be set to NULL.
 */
static int _srv_parse_init(struct server **srv, char **args, int *cur_arg,
                           struct proxy *curproxy,
                           int parse_flags)
{
	struct server *newsrv = NULL;
	const char *err = NULL;
	int err_code = 0;
	char *fqdn = NULL;
	int tmpl_range_low = 0, tmpl_range_high = 0;
	char *errmsg = NULL;

	*srv = NULL;

	/* There is no mandatory first arguments for default server. */
	if (parse_flags & SRV_PARSE_PARSE_ADDR) {
		if (parse_flags & SRV_PARSE_TEMPLATE) {
			if (!*args[3]) {
				/* 'server-template' line number of argument check. */
				ha_alert("'%s' expects <prefix> <nb | range> <addr>[:<port>] as arguments.\n",
				         args[0]);
				err_code |= ERR_ALERT | ERR_FATAL;
				goto out;
			}

			err = invalid_prefix_char(args[1]);
		}
		else {
			if (!*args[2]) {
				/* 'server' line number of argument check. */
				ha_alert("'%s' expects <name> and <addr>[:<port>] as arguments.\n",
				         args[0]);
				err_code |= ERR_ALERT | ERR_FATAL;
				goto out;
			}

			err = invalid_char(args[1]);
		}

		if (err) {
			ha_alert("character '%c' is not permitted in %s %s '%s'.\n",
			         *err, args[0], !(parse_flags & SRV_PARSE_TEMPLATE) ? "name" : "prefix", args[1]);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}
	}

	*cur_arg = 2;
	if (parse_flags & SRV_PARSE_TEMPLATE) {
		/* Parse server-template <nb | range> arg. */
		if (_srv_parse_tmpl_range(newsrv, args[*cur_arg], &tmpl_range_low, &tmpl_range_high) < 0) {
			ha_alert("Wrong %s number or range arg '%s'.\n",
			         args[0], args[*cur_arg]);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}
		(*cur_arg)++;
	}

	if (!(parse_flags & SRV_PARSE_DEFAULT_SERVER)) {
		struct sockaddr_storage *sk;
		int port1, port2, port;

		*srv = newsrv = new_server(curproxy);
		if (!newsrv) {
			ha_alert("out of memory.\n");
			err_code |= ERR_ALERT | ERR_ABORT;
			goto out;
		}
		register_parsing_obj(&newsrv->obj_type);

		if (parse_flags & SRV_PARSE_TEMPLATE) {
			newsrv->tmpl_info.nb_low = tmpl_range_low;
			newsrv->tmpl_info.nb_high = tmpl_range_high;
		}

		if (parse_flags & SRV_PARSE_DYNAMIC)
			newsrv->flags |= SRV_F_DYNAMIC;

		/* Note: for a server template, its id is its prefix.
		 * This is a temporary id which will be used for server allocations to come
		 * after parsing.
		 */
		if (!(parse_flags & SRV_PARSE_TEMPLATE))
			newsrv->id = strdup(args[1]);
		else
			newsrv->tmpl_info.prefix = strdup(args[1]);

		/* several ways to check the port component :
		 *  - IP    => port=+0, relative (IPv4 only)
		 *  - IP:   => port=+0, relative
		 *  - IP:N  => port=N, absolute
		 *  - IP:+N => port=+N, relative
		 *  - IP:-N => port=-N, relative
		 */
		if (!(parse_flags & SRV_PARSE_PARSE_ADDR))
			goto skip_addr;

		sk = str2sa_range(args[*cur_arg], &port, &port1, &port2, NULL, NULL, &newsrv->addr_type,
		                  &errmsg, NULL, &fqdn,
		                  (parse_flags & SRV_PARSE_INITIAL_RESOLVE ? PA_O_RESOLVE : 0) | PA_O_PORT_OK |
				  (parse_flags & SRV_PARSE_IN_PEER_SECTION ? PA_O_PORT_MAND : PA_O_PORT_OFS) |
				  PA_O_STREAM | PA_O_DGRAM | PA_O_XPRT);
		if (!sk) {
			ha_alert("%s\n", errmsg);
			err_code |= ERR_ALERT | ERR_FATAL;
			ha_free(&errmsg);
			goto out;
		}

		if (!port1 || !port2) {
			if (sk->ss_family != AF_CUST_RHTTP_SRV) {
				/* no port specified, +offset, -offset */
				newsrv->flags |= SRV_F_MAPPORTS;
			}
			else {
				newsrv->flags |= SRV_F_RHTTP;
			}
		}

		/* save hostname and create associated name resolution */
		if (fqdn) {
			if (fqdn[0] == '_') { /* SRV record */
				/* Check if a SRV request already exists, and if not, create it */
				if ((newsrv->srvrq = find_srvrq_by_name(fqdn, curproxy)) == NULL)
					newsrv->srvrq = new_resolv_srvrq(newsrv, fqdn);
				if (newsrv->srvrq == NULL) {
					err_code |= ERR_ALERT | ERR_FATAL;
					goto out;
				}
				LIST_APPEND(&newsrv->srvrq->attached_servers, &newsrv->srv_rec_item);
			}
			else if (srv_prepare_for_resolution(newsrv, fqdn) == -1) {
				ha_alert("Can't create DNS resolution for server '%s'\n",
				         newsrv->id);
				err_code |= ERR_ALERT | ERR_FATAL;
				goto out;
			}
		}

		newsrv->addr = *sk;
		newsrv->svc_port = port;
		/*
		 * we don't need to lock the server here, because
		 * we are in the process of initializing.
		 *
		 * Note that the server is not attached into the proxy tree if
		 * this is a dynamic server.
		 */
		srv_set_addr_desc(newsrv, !(parse_flags & SRV_PARSE_DYNAMIC));

		if (!newsrv->srvrq && !newsrv->hostname &&
		    !protocol_lookup(newsrv->addr.ss_family, PROTO_TYPE_STREAM, 0)) {
			ha_alert("Unknown protocol family %d '%s'\n",
			         newsrv->addr.ss_family, args[*cur_arg]);
			err_code |= ERR_ALERT | ERR_FATAL;
			goto out;
		}

		(*cur_arg)++;
 skip_addr:
		if (!(parse_flags & SRV_PARSE_DYNAMIC)) {
			/* Copy default server settings to new server */
			srv_settings_cpy(newsrv, &curproxy->defsrv, 0);
		} else {
			srv_settings_init(newsrv);

			/* A dynamic server is disabled on startup */
			newsrv->next_admin = SRV_ADMF_FMAINT;
			newsrv->next_state = SRV_ST_STOPPED;
			server_recalc_eweight(newsrv, 0);
		}
		HA_SPIN_INIT(&newsrv->lock);
	}
	else {
		*srv = newsrv = &curproxy->defsrv;
		*cur_arg = 1;
	}

	free(fqdn);
	if (!(curproxy->cap & PR_CAP_LB)) {
		/* No need to wait for effective proxy mode, it is already known:
		 * Only general purpose user-declared proxies ("listen", "frontend", "backend")
		 * offer the possibility to configure the mode of the proxy. Hopefully for us,
		 * they have the PR_CAP_LB set.
		 */
		return _srv_check_proxy_mode(newsrv, 0);
	}
	return 0;

out:
	free(fqdn);
	return err_code;
}

/* Parse the server keyword in <args>.
 * <cur_arg> is incremented beyond the keyword optional value. Note that this
 * might not be the case if an error is reported.
 *
 * This function is first intended to be used through parse_server to
 * initialize a new server on startup.
 *
 * A mask of errors is returned. ERR_FATAL is set if the parsing should be
 * interrupted.
 */
static int _srv_parse_kw(struct server *srv, char **args, int *cur_arg,
                         struct proxy *curproxy,
                         int parse_flags)
{
	int err_code = 0;
	struct srv_kw *kw;
	const char *best;
	char *errmsg = NULL;

	kw = srv_find_kw(args[*cur_arg]);
	if (!kw) {
		best = srv_find_best_kw(args[*cur_arg]);
		if (best)
			ha_alert("unknown keyword '%s'; did you mean '%s' maybe ?%s\n",
			         args[*cur_arg], best,
				 (parse_flags & SRV_PARSE_PARSE_ADDR) ? "" :
				 " Hint: no address was expected for this server.");
		else
			ha_alert("unknown keyword '%s'.%s\n", args[*cur_arg],
				 (parse_flags & SRV_PARSE_PARSE_ADDR) ? "" :
				 " Hint: no address was expected for this server.");

		return ERR_ALERT | ERR_FATAL;
	}

	if (!kw->parse) {
		ha_alert("'%s' option is not implemented in this version (check build options)\n",
		         args[*cur_arg]);
		err_code = ERR_ALERT | ERR_FATAL;
		goto out;
	}

	if ((parse_flags & SRV_PARSE_DEFAULT_SERVER) && !kw->default_ok) {
		ha_alert("'%s' option is not accepted in default-server sections\n",
		         args[*cur_arg]);
		err_code = ERR_ALERT;
		goto out;
	}
	else if ((parse_flags & SRV_PARSE_DYNAMIC) && !kw->dynamic_ok) {
		ha_alert("'%s' option is not accepted for dynamic server\n",
		         args[*cur_arg]);
		err_code |= ERR_ALERT;
		goto out;
	}

	err_code = kw->parse(args, cur_arg, curproxy, srv, &errmsg);
	if (err_code) {
		display_parser_err(NULL, 0, args, *cur_arg, err_code, &errmsg);
		free(errmsg);
	}

out:
	if (kw->skip != -1)
		*cur_arg += 1 + kw->skip;

	return err_code;
}

/* Server initializations finalization.
 * Initialize health check, agent check, SNI expression and outgoing TLVs if enabled.
 * Must not be called for a default server instance.
 *
 * This function is first intended to be used through parse_server to
 * initialize a new server on startup.
 */
static int _srv_parse_finalize(char **args, int cur_arg,
                               struct server *srv, struct proxy *px,
                               int parse_flags)
{
	int ret;
	char *errmsg = NULL;
	struct srv_pp_tlv_list *srv_tlv = NULL;

	if (srv->do_check && srv->trackit) {
		ha_alert("unable to enable checks and tracking at the same time!\n");
		return ERR_ALERT | ERR_FATAL;
	}

	if (srv->do_agent && !srv->agent.port) {
		ha_alert("server %s does not have agent port. Agent check has been disabled.\n",
		         srv->id);
		return ERR_ALERT | ERR_FATAL;
	}

	if ((ret = parse_srv_expr(srv->sni_expr, &srv->ssl_ctx.sni, px, &errmsg))) {
		if (errmsg) {
			ha_alert("error detected while parsing sni expression : %s.\n", errmsg);
			free(errmsg);
		}
		return ret;
	}

	/* Use sni as fallback if pool_conn_name isn't set */
	if (!srv->pool_conn_name && srv->sni_expr) {
		srv->pool_conn_name = strdup(srv->sni_expr);
		if (!srv->pool_conn_name) {
			ha_alert("out of memory\n");
			return ERR_ALERT | ERR_FATAL;
		}
	}

	if ((ret = parse_srv_expr(srv->pool_conn_name, &srv->pool_conn_name_expr,
	                          px, &errmsg))) {
		if (errmsg) {
			ha_alert("error detected while parsing pool-conn-name expression : %s.\n", errmsg);
			free(errmsg);
		}
		return ret;
	}

	/* A dynamic server is disabled on startup. It must not be counted as
	 * an active backend entry.
	 */
	if (!(parse_flags & SRV_PARSE_DYNAMIC)) {
		if (srv->flags & SRV_F_BACKUP)
			px->srv_bck++;
		else
			px->srv_act++;
	}

	list_for_each_entry(srv_tlv, &srv->pp_tlvs, list) {
		lf_expr_init(&srv_tlv->fmt);
		if (srv_tlv->fmt_string && unlikely(!parse_logformat_string(srv_tlv->fmt_string,
			srv->proxy, &srv_tlv->fmt, 0, SMP_VAL_BE_SRV_CON, &errmsg))) {
			if (errmsg) {
				ha_alert("%s\n", errmsg);
				free(errmsg);
			}
			return ERR_ALERT | ERR_FATAL;
		}
	}

	srv_lb_commit_status(srv);

	return 0;
}

int parse_server(const char *file, int linenum, char **args,
                 struct proxy *curproxy, const struct proxy *defproxy,
                 int parse_flags)
{
	struct server *newsrv = NULL;
	int err_code = 0;

	int cur_arg;

	set_usermsgs_ctx(file, linenum, NULL);

	if (!(parse_flags & SRV_PARSE_DEFAULT_SERVER) && curproxy == defproxy) {
		ha_alert("'%s' not allowed in 'defaults' section.\n", args[0]);
		err_code |= ERR_ALERT | ERR_FATAL;
		goto out;
	}
	else if (failifnotcap(curproxy, PR_CAP_BE, file, linenum, args[0], NULL)) {
		err_code |= ERR_ALERT | ERR_FATAL;
		goto out;
	}

	if ((parse_flags & (SRV_PARSE_IN_PEER_SECTION|SRV_PARSE_PARSE_ADDR)) ==
	    (SRV_PARSE_IN_PEER_SECTION|SRV_PARSE_PARSE_ADDR)) {
		if (!*args[2])
			return 0;
	}

	err_code = _srv_parse_init(&newsrv, args, &cur_arg, curproxy,
	                           parse_flags);

	/* the servers are linked backwards first */
	if (newsrv && !(parse_flags & SRV_PARSE_DEFAULT_SERVER)) {
		newsrv->next = curproxy->srv;
		curproxy->srv = newsrv;
	}

	if (err_code & ERR_CODE)
		goto out;

	if (!newsrv->conf.file) // note: do it only once for default-server
		newsrv->conf.file = strdup(file);
	newsrv->conf.line = linenum;

	while (*args[cur_arg]) {
		err_code = _srv_parse_kw(newsrv, args, &cur_arg, curproxy,
		                         parse_flags);
		if (err_code & ERR_FATAL)
			goto out;
	}

	if (!(parse_flags & SRV_PARSE_DEFAULT_SERVER)) {
		err_code |= _srv_parse_finalize(args, cur_arg, newsrv, curproxy, parse_flags);
		if (err_code & ERR_FATAL)
			goto out;
	}

	if (parse_flags & SRV_PARSE_TEMPLATE) {
		_srv_parse_tmpl_init(newsrv, curproxy);
	}
	else if (!(parse_flags & SRV_PARSE_DEFAULT_SERVER)) {
		newsrv->conf.name.key = newsrv->id;
		ebis_insert(&curproxy->conf.used_server_name, &newsrv->conf.name);
	}

	/* If the server id is fixed, insert it in the proxy used_id tree.
	 * This is needed to detect a later duplicate id via srv_parse_id.
	 *
	 * If no is specified, a dynamic one is generated in
	 * check_config_validity.
	 */
	if (newsrv->flags & SRV_F_FORCED_ID)
		eb32_insert(&curproxy->conf.used_server_id, &newsrv->conf.id);

	HA_DIAG_WARNING_COND((curproxy->cap & PR_CAP_LB) && !newsrv->uweight,
	                     "configured with weight of 0 will never be selected by load balancing algorithms\n");

	reset_usermsgs_ctx();
	return 0;

 out:
	reset_usermsgs_ctx();
	return err_code;
}

/* Returns a pointer to the first server matching either id <id>.
 * NULL is returned if no match is found.
 * the lookup is performed in the backend <bk>
 */
struct server *server_find_by_id(struct proxy *bk, int id)
{
	struct eb32_node *eb32;
	struct server *curserver;

	if (!bk || (id ==0))
		return NULL;

	/* <bk> has no backend capabilities, so it can't have a server */
	if (!(bk->cap & PR_CAP_BE))
		return NULL;

	curserver = NULL;

	eb32 = eb32_lookup(&bk->conf.used_server_id, id);
	if (eb32)
		curserver = container_of(eb32, struct server, conf.id);

	return curserver;
}

/*
 * This function finds a server with matching "<puid> x <rid>" within
 * selected backend <bk>.
 * Using the combination of proxy-uid + revision id ensures that the function
 * will either return the server we're expecting or NULL if it has been removed
 * from the proxy (<id> is unique within the list, but it is not true over the
 * process lifetime as new servers may reuse the id of a previously deleted
 * server).
 */
struct server *server_find_by_id_unique(struct proxy *bk, int id, uint32_t rid)
{
	struct server *curserver;

	curserver = server_find_by_id(bk, id);
	if (!curserver || curserver->rid != rid)
		return NULL;
	return curserver;
}

/* Returns a pointer to the first server matching either name <name>, or id
 * if <name> starts with a '#'. NULL is returned if no match is found.
 * the lookup is performed in the backend <bk>
 */
struct server *server_find_by_name(struct proxy *bk, const char *name)
{
	struct server *curserver;

	if (!bk || !name)
		return NULL;

	/* <bk> has no backend capabilities, so it can't have a server */
	if (!(bk->cap & PR_CAP_BE))
		return NULL;

	curserver = NULL;
	if (*name == '#') {
		curserver = server_find_by_id(bk, atoi(name + 1));
	}
	else {
		struct ebpt_node *node;

		node = ebis_lookup(&bk->conf.used_server_name, name);
		if (node)
			curserver = container_of(node, struct server, conf.name);
	}

	return curserver;
}

/*
 * This function finds a server with matching "<name> x <rid>" within
 * selected backend <bk>.
 * Using the combination of name + revision id ensures that the function
 * will either return the server we're expecting or NULL if it has been removed
 * from the proxy. For this we assume that <name> is unique within the list,
 * which is the case in most setups, but in rare cases the user may have
 * enforced duplicate server names in the initial config (ie: if he intends to
 * use numerical IDs for identification instead). In this particular case, the
 * function will not work as expected so server_find_by_id_unique() should be
 * used to match a unique server instead.
 *
 * Just like server_find_by_id_unique(), if a server is deleted and a new server
 * reuses the same name, the rid check will prevent the function from returning
 * a different server from the one we were expecting to match against at a given
 * time.
 */
struct server *server_find_by_name_unique(struct proxy *bk, const char *name, uint32_t rid)
{
	struct server *curserver;

	curserver = server_find_by_name(bk, name);
	if (!curserver || curserver->rid != rid)
		return NULL;
	return curserver;
}

struct server *server_find_best_match(struct proxy *bk, char *name, int id, int *diff)
{
	struct server *byname;
	struct server *byid;

	if (!name && !id)
		return NULL;

	if (diff)
		*diff = 0;

	byname = byid = NULL;

	if (name) {
		byname = server_find_by_name(bk, name);
		if (byname && (!id || byname->puid == id))
			return byname;
	}

	/* remaining possibilities :
	 *  - name not set
	 *  - name set but not found
	 *  - name found but ID doesn't match
	 */
	if (id) {
		byid = server_find_by_id(bk, id);
		if (byid) {
			if (byname) {
				/* use id only if forced by configuration */
				if (byid->flags & SRV_F_FORCED_ID) {
					if (diff)
						*diff |= 2;
					return byid;
				}
				else {
					if (diff)
						*diff |= 1;
					return byname;
				}
			}

			/* remaining possibilities:
			 *   - name not set
			 *   - name set but not found
			 */
			if (name && diff)
				*diff |= 2;
			return byid;
		}

		/* id bot found */
		if (byname) {
			if (diff)
				*diff |= 1;
			return byname;
		}
	}

	return NULL;
}

/* This functions retrieves server's addr and port to fill
 * <inetaddr> struct passed as argument.
 *
 * This may only be used under inet context.
 */
void server_get_inetaddr(struct server *s, struct server_inetaddr *inetaddr)
{
	struct sockaddr_storage *addr = &s->addr;
	unsigned int port = s->svc_port;
	uint8_t mapports = !!(s->flags & SRV_F_MAPPORTS);

	/* only INET families are supported */
	BUG_ON((addr->ss_family != AF_UNSPEC &&
	        addr->ss_family != AF_INET && addr->ss_family != AF_INET6));

	inetaddr->family = addr->ss_family;
	memset(&inetaddr->addr, 0, sizeof(inetaddr->addr));

	if (addr->ss_family == AF_INET)
		inetaddr->addr.v4 =
			((struct sockaddr_in *)addr)->sin_addr;
	else if (addr->ss_family == AF_INET6)
		inetaddr->addr.v6 =
			((struct sockaddr_in6 *)addr)->sin6_addr;

	inetaddr->port.svc = port;
	inetaddr->port.map = mapports;
}

/* get human readable name for server_inetaddr_updater .by struct member
 */
const char *server_inetaddr_updater_by_to_str(enum server_inetaddr_updater_by by)
{
	switch (by) {
		case SERVER_INETADDR_UPDATER_BY_CLI:
			return "stats socket command";
		case SERVER_INETADDR_UPDATER_BY_LUA:
			return "Lua script";
		case SERVER_INETADDR_UPDATER_BY_DNS_AR:
			return "DNS additional record";
		case SERVER_INETADDR_UPDATER_BY_DNS_CACHE:
			return "DNS cache";
		case SERVER_INETADDR_UPDATER_BY_DNS_RESOLVER:
			return "DNS resolver";
		default:
			/* unknown, don't mention updater */
			break;
	}
	return NULL;
}

/* append inetaddr updater info to chunk <out>
 */
static void _srv_append_inetaddr_updater_info(struct buffer *out,
                                              struct server *s,
                                              struct server_inetaddr_updater updater)
{
	switch (updater.by) {
		case SERVER_INETADDR_UPDATER_BY_DNS_RESOLVER:
			/* we need to report the resolver/nameserver id which is
			 * responsible for the update
			 */
			{
				struct resolvers *r = s->resolvers;
				struct dns_nameserver *ns;

				/* we already know that the update comes from the
				 * resolver section linked to the server, but we
				 * need to find out which nameserver handled the dns
				 * query
				 */
				BUG_ON(!r);
				ns = find_nameserver_by_resolvers_and_id(r, updater.u.dns_resolver.ns_id);
				BUG_ON(!ns);
				chunk_appendf(out, " by '%s/%s'", r->id, ns->id);
			}
			break;
		default:
			{
				const char *by_name;

				by_name = server_inetaddr_updater_by_to_str(updater.by);
				if (by_name)
					chunk_appendf(out, " by '%s'", by_name);
			}
			break;
	}
}

/* server_set_inetaddr() helper */
static void _addr_to_str(int family, const void *addr, char *addr_str, size_t len)
{
	memset(addr_str, 0, len);
	switch (family) {
		case AF_INET:
		case AF_INET6:
			inet_ntop(family, addr, addr_str, len);
			break;
		default:
			strlcpy2(addr_str, "(none)", len);
			break;
	}
}
/* server_set_inetaddr() helper */
static int _inetaddr_addr_cmp(const struct server_inetaddr *inetaddr, const struct sockaddr_storage *addr)
{
	struct in_addr *v4;
	struct in6_addr *v6;

	if (inetaddr->family != addr->ss_family)
		return 1;

	if (inetaddr->family == AF_INET) {
		v4 = &((struct sockaddr_in *)addr)->sin_addr;
		if (memcmp(&inetaddr->addr.v4, v4, sizeof(struct in_addr)))
			return 1;
	}
	else if (inetaddr->family == AF_INET6) {
		v6 = &((struct sockaddr_in6 *)addr)->sin6_addr;
		if (memcmp(&inetaddr->addr.v6, v6, sizeof(struct in6_addr)))
			return 1;
	}

	return 0; // both inetaddr storage are equivalent
}

/* This function sets a server's addr and port in inet context based on new
 * inetaddr input
 *
 * The function first does the following, in that order:
 * - checks if an update is required (new IP or port is different than current
 * one)
 * - check the update is allowed:
 *  - allow all changes if no CHECKS are configured
 *  - if CHECK is configured:
 *   - if switch to port map (SRV_F_MAPPORTS), ensure health check have their
 *     own ports
 *  - applies required changes to both ADDR and PORT if both 'required' and
 *    'allowed' conditions are met.
 *
 * Caller can pass <msg> buffer so that it gets some information about the
 * operation. It may as well provide <updater> so that messages mention that
 * the update was performed on the behalf of it.
 *
 * <inetaddr> family may be set to UNSPEC to reset server's addr
 *
 * Caller must set <inetaddr>->port.map to 1 if <inetaddr>->port.svc must be
 * handled as an offset
 *
 * The function returns 1 if an update was performed and 0 if nothing was
 * changed.
 */
int server_set_inetaddr(struct server *s,
                        const struct server_inetaddr *inetaddr,
                        struct server_inetaddr_updater updater, struct buffer *msg)
{
	union {
		struct event_hdl_cb_data_server_inetaddr addr;
		struct event_hdl_cb_data_server common;
	} cb_data;
	char addr_str[INET6_ADDRSTRLEN];
	uint16_t current_port;
	uint8_t ip_change = 0;
	uint8_t port_change = 0;
	int ret = 0;

	/* only INET families are supported */
	BUG_ON((inetaddr->family != AF_UNSPEC &&
	        inetaddr->family != AF_INET && inetaddr->family != AF_INET6) ||
	       (s->addr.ss_family != AF_UNSPEC &&
	        s->addr.ss_family != AF_INET && s->addr.ss_family != AF_INET6));

	/* ignore if no change */
	if (!_inetaddr_addr_cmp(inetaddr, &s->addr))
		goto port;

	ip_change = 1;

	/* update report for caller */
	if (msg) {
		void *from_ptr = NULL;

		if (s->addr.ss_family == AF_INET)
			from_ptr = &((struct sockaddr_in *)&s->addr)->sin_addr;
		else if (s->addr.ss_family == AF_INET6)
			from_ptr = &((struct sockaddr_in6 *)&s->addr)->sin6_addr;

		_addr_to_str(s->addr.ss_family, from_ptr, addr_str, sizeof(addr_str));
		chunk_printf(msg, "IP changed from '%s'", addr_str);
		_addr_to_str(inetaddr->family, &inetaddr->addr, addr_str, sizeof(addr_str));
		chunk_appendf(msg, " to '%s'", addr_str);
	}

	if (inetaddr->family == AF_UNSPEC)
		goto out; // ignore port information when unsetting addr

 port:

	/* collection data currently setup */
	current_port = s->svc_port;

	/* check if caller triggers a port mapped or offset */
	if (inetaddr->port.map) {
		/* check if server currently uses port map */
		if (!(s->flags & SRV_F_MAPPORTS)) {
			/* we're switching from a fixed port to a SRV_F_MAPPORTS
			 * (mapped) port, prevent PORT change if check is enabled
			 * and it doesn't have it's dedicated port while switching
			 * to port mapping
			 */
			if ((s->check.state & CHK_ST_ENABLED) && !s->check.port) {
				if (msg) {
					if (ip_change)
						chunk_appendf(msg, ", ");
					chunk_appendf(msg, "can't change <port> to port map because it is incompatible with current health check port configuration (use 'port' statement from the 'server' directive).");
				}
				goto out;
			}
			/* switch from fixed port to port map mandatorily triggers
			 * a port change
			 */
			port_change = 1;
		}
		/* else we're already using port maps */
		else {
			port_change = current_port != inetaddr->port.svc;
		}
	}
	/* fixed port */
	else {
		if ((s->flags & SRV_F_MAPPORTS))
			port_change = 1; // changing from mapped to fixed
		else
			port_change = current_port != inetaddr->port.svc;
	}

	/* update response message about PORT change */
	if (port_change && msg) {
		if (ip_change)
			chunk_appendf(msg, ", ");

		chunk_appendf(msg, "port changed from '");
		if (s->flags & SRV_F_MAPPORTS)
			chunk_appendf(msg, "+");

		chunk_appendf(msg, "%d' to '", s->svc_port);
		if (inetaddr->port.map)
			chunk_appendf(msg, "+");
		chunk_appendf(msg, "%d'", inetaddr->port.svc);
	}

 out:
	if (ip_change || port_change) {
		_srv_event_hdl_prepare(&cb_data.common, s, 0);
		_srv_event_hdl_prepare_inetaddr(&cb_data.addr, s,
		                                inetaddr,
		                                updater);

		/* server_atomic_sync_task will apply the changes for us */
		_srv_event_hdl_publish(EVENT_HDL_SUB_SERVER_INETADDR, cb_data, s);

		ret = 1;
	}

	if (ret && msg && updater.by != SERVER_INETADDR_UPDATER_BY_NONE)
		_srv_append_inetaddr_updater_info(msg, s, updater);
	return ret;
}

/* Sets new server's addr and/or svc_port, then send a log and report a
 * warning on stderr if something has changed.
 *
 * Returns 1 if something has changed, 0 otherwise.
 * see server_set_inetaddr() for more information.
 */
int server_set_inetaddr_warn(struct server *s,
                             const struct server_inetaddr *inetaddr,
                             struct server_inetaddr_updater updater)
{
	struct buffer *msg = get_trash_chunk();
	int ret;

	chunk_reset(msg);

	ret = server_set_inetaddr(s, inetaddr, updater, msg);
	if (msg->data) {
		/* write the buffer on stderr */
		ha_warning("%s/%s: %s.\n", s->proxy->id, s->id, msg->area);

		/* send a log */
		send_log(s->proxy, LOG_NOTICE, "%s/%s: %s.\n", s->proxy->id, s->id, msg->area);
	}
	return ret;
}

/*
 * update a server's current IP address.
 * ip is a pointer to the new IP address, whose address family is ip_sin_family.
 * ip is in network format.
 * updater is a string which contains an information about the requester of the update.
 * updater is used if not NULL.
 *
 * A log line and a stderr warning message is generated based on server's backend options.
 *
 * Must be called with the server lock held.
 */
int srv_update_addr(struct server *s, void *ip, int ip_sin_family, struct server_inetaddr_updater updater)
{
	struct server_inetaddr inetaddr;

	server_get_inetaddr(s, &inetaddr);
	BUG_ON(ip_sin_family != AF_INET && ip_sin_family != AF_INET6);

	/* save the new IP family */
	inetaddr.family = ip_sin_family;
	/* save the new IP address */
	switch (ip_sin_family) {
	case AF_INET:
		memcpy(&inetaddr.addr.v4, ip, 4);
		break;
	case AF_INET6:
		memcpy(&inetaddr.addr.v6, ip, 16);
		break;
	};

	server_set_inetaddr_warn(s, &inetaddr, updater);

	return 0;
}

/* update agent health check address and port
 * addr can be ip4/ip6 or a hostname
 * if one error occurs, don't apply anything
 * must be called with the server lock held.
 */
const char *srv_update_agent_addr_port(struct server *s, const char *addr, const char *port)
{
	struct sockaddr_storage sk;
	struct buffer *msg;
	int new_port;

	msg = get_trash_chunk();
	chunk_reset(msg);

	if (!(s->agent.state & CHK_ST_ENABLED)) {
		chunk_strcat(msg, "agent checks are not enabled on this server");
		goto out;
	}
	if (addr) {
		memset(&sk, 0, sizeof(struct sockaddr_storage));
		if (str2ip(addr, &sk) == NULL) {
			chunk_appendf(msg, "invalid addr '%s'", addr);
			goto out;
		}
	}
	if (port) {
		if (strl2irc(port, strlen(port), &new_port) != 0) {
			chunk_appendf(msg, "provided port is not an integer");
			goto out;
		}
		if (new_port < 0 || new_port > 65535) {
			chunk_appendf(msg, "provided port is invalid");
			goto out;
		}
	}
out:
	if (msg->data)
		return msg->area;
	else {
		if (addr)
			set_srv_agent_addr(s, &sk);
		if (port)
			set_srv_agent_port(s, new_port);
	}
	return NULL;
}

/* update server health check address and port
 * addr must be ip4 or ip6, it won't be resolved
 * if one error occurs, don't apply anything
 * must be called with the server lock held.
 */
const char *srv_update_check_addr_port(struct server *s, const char *addr, const char *port)
{
	struct sockaddr_storage sk;
	struct buffer *msg;
	int new_port;

	msg = get_trash_chunk();
	chunk_reset(msg);

	if (!(s->check.state & CHK_ST_ENABLED)) {
		chunk_strcat(msg, "health checks are not enabled on this server");
		goto out;
	}
	if (addr) {
		memset(&sk, 0, sizeof(struct sockaddr_storage));
		if (str2ip2(addr, &sk, 0) == NULL) {
			chunk_appendf(msg, "invalid addr '%s'", addr);
			goto out;
		}
	}
	if (port) {
		if (strl2irc(port, strlen(port), &new_port) != 0) {
			chunk_appendf(msg, "provided port is not an integer");
			goto out;
		}
		if (new_port < 0 || new_port > 65535) {
			chunk_appendf(msg, "provided port is invalid");
			goto out;
		}
		/* prevent the update of port to 0 if MAPPORTS are in use */
		if ((s->flags & SRV_F_MAPPORTS) && new_port == 0) {
			chunk_appendf(msg, "can't unset 'port' since MAPPORTS is in use");
			goto out;
		}
	}
out:
	if (msg->data)
		return msg->area;
	else {
		if (addr)
			s->check.addr = sk;
		if (port)
			s->check.port = new_port;
	}
	return NULL;
}

/*
 * This function update a server's addr and port only for AF_INET and AF_INET6 families.
 *
 * Caller can pass its info through <updater> to get it integrated in the response
 * message returned by the function.
 *
 * The function first does the following, in that order:
 * - checks that don't switch from/to a family other than AF_INET and AF_INET6
 * - validates the new addr and/or port
 * - calls server_set_inetaddr() to check and apply the change
 *
 * Must be called with the server lock held.
 */
const char *srv_update_addr_port(struct server *s, const char *addr, const char *port,
                                 struct server_inetaddr_updater updater)
{
	struct sockaddr_storage sa;
	struct server_inetaddr inetaddr;
	struct buffer *msg;
	int ret;

	msg = get_trash_chunk();
	chunk_reset(msg);

	/* even a simple port change is not supported outside of inet context, because
	 * s->svc_port is only relevant under inet context
	*/
	if ((s->addr.ss_family != AF_INET) && (s->addr.ss_family != AF_INET6)) {
		chunk_printf(msg, "Update for the current server address family is only supported through configuration file.");
		goto out;
	}

	server_get_inetaddr(s, &inetaddr);

	if (addr) {
		memset(&sa, 0, sizeof(struct sockaddr_storage));
		if (str2ip2(addr, &sa, 0) == NULL) {
			chunk_printf(msg, "Invalid addr '%s'", addr);
			goto out;
		}

		/* changes are allowed on AF_INET* families only */
		if ((sa.ss_family != AF_INET) && (sa.ss_family != AF_INET6)) {
			chunk_printf(msg, "Update to families other than AF_INET and AF_INET6 supported only through configuration file");
			goto out;
		}

		inetaddr.family = sa.ss_family;
		switch (inetaddr.family) {
			case AF_INET:
				inetaddr.addr.v4 = ((struct sockaddr_in *)&sa)->sin_addr;
			break;
			case AF_INET6:
				inetaddr.addr.v6 = ((struct sockaddr_in6 *)&sa)->sin6_addr;
			break;
		}
	}

	if (port) {
		uint16_t new_port;
		char sign = '\0';
		char *endptr;

		sign = *port;

		errno = 0;
		new_port = strtol(port, &endptr, 10);
		if ((errno != 0) || (port == endptr)) {
			chunk_appendf(msg, "problem converting port '%s' to an int", port);
			goto out;
		}

		/* check if caller triggers a port mapped or offset */
		if (sign == '-' || sign == '+')
			inetaddr.port.map = 1;
		else
			inetaddr.port.map = 0;

		inetaddr.port.svc = new_port;

		/* note: negative offset was converted to positive offset
		 * (new_port is unsigned) to prevent later conversions errors
		 * since svc_port is handled as an unsigned int all along the
		 * chain. Unfortunately this is a one-way operation so the user
		 * could be surprised to see a negative offset reported using
		 * its equivalent positive offset in the generated message
		 * (-X = +(65535 - (X-1))), but thanks to proper wraparound it
		 * will be interpreted as a negative offset during port
		 * remapping so it will work as expected.
		 */
	}

	ret = server_set_inetaddr(s, &inetaddr, updater, msg);
	if (!ret)
		chunk_printf(msg, "nothing changed");

 out:
	return msg->area;
}

/*
 * put the server in maintenance because of failing SRV resolution
 * returns:
 *  0 if server was put under maintenance
 *  1 if server status has not changed
 *
 * Must be called with the server lock held.
 */
int srvrq_set_srv_down(struct server *s)
{
	if (!s->srvrq)
		return 1;

	if (s->next_admin & SRV_ADMF_RMAINT)
		return 1;

	srv_set_admin_flag(s, SRV_ADMF_RMAINT, SRV_ADM_STCHGC_DNS_NOENT);
	return 0;
}

/*
 * put server under maintenance as a result of name resolution
 * returns:
 *  0 if server was put under maintenance
 *  1 if server status has not changed
 *
 * Must be called with the server lock held.
 */
int snr_set_srv_down(struct server *s)
{
	struct resolvers  *resolvers  = s->resolvers;
	struct resolv_resolution *resolution = (s->resolv_requester ? s->resolv_requester->resolution : NULL);
	int exp;

	/* server already under maintenance */
	if (s->next_admin & SRV_ADMF_RMAINT)
		goto out;

	/* If resolution is NULL we're dealing with SRV records Additional records */
	if (resolution == NULL)
		return srvrq_set_srv_down(s);

	switch (resolution->status) {
		case RSLV_STATUS_NONE:
			/* status when HAProxy has just (re)started.
			 * Nothing to do, since the task is already automatically started */
			goto out;

		case RSLV_STATUS_VALID:
			/*
			 * valid resolution but no usable server address
			 */
			srv_set_admin_flag(s, SRV_ADMF_RMAINT, SRV_ADM_STCHGC_DNS_NOIP);
			return 0;

		case RSLV_STATUS_NX:
			/* stop server if resolution is NX for a long enough period */
			exp = tick_add(resolution->last_valid, resolvers->hold.nx);
			if (!tick_is_expired(exp, now_ms))
				goto out; // not yet expired

			srv_set_admin_flag(s, SRV_ADMF_RMAINT, SRV_ADM_STCHGC_DNS_NX);
			return 0;

		case RSLV_STATUS_TIMEOUT:
			/* stop server if resolution is TIMEOUT for a long enough period */
			exp = tick_add(resolution->last_valid, resolvers->hold.timeout);
			if (!tick_is_expired(exp, now_ms))
				goto out; // not yet expired

			srv_set_admin_flag(s, SRV_ADMF_RMAINT, SRV_ADM_STCHGC_DNS_TIMEOUT);
			return 0;

		case RSLV_STATUS_REFUSED:
			/* stop server if resolution is REFUSED for a long enough period */
			exp = tick_add(resolution->last_valid, resolvers->hold.refused);
			if (!tick_is_expired(exp, now_ms))
				goto out; // not yet expired

			srv_set_admin_flag(s, SRV_ADMF_RMAINT, SRV_ADM_STCHGC_DNS_REFUSED);
			return 0;

		default:
			/* stop server if resolution failed for a long enough period */
			exp = tick_add(resolution->last_valid, resolvers->hold.other);
			if (!tick_is_expired(exp, now_ms))
				goto out; // not yet expired

			srv_set_admin_flag(s, SRV_ADMF_RMAINT, SRV_ADM_STCHGC_DNS_UNSPEC);
			return 0;
	}

 out:
	return 1;
}

/*
 * Server Name Resolution valid response callback
 * It expects:
 *  - <nameserver>: the name server which answered the valid response
 *  - <response>: buffer containing a valid DNS response
 *  - <response_len>: size of <response>
 * It performs the following actions:
 *  - ignore response if current ip found and server family not met
 *  - update with first new ip found if family is met and current IP is not found
 * returns:
 *  0 on error
 *  1 when no error or safe ignore
 *
 * Must be called with server lock held
 */
int snr_resolution_cb(struct resolv_requester *requester, struct dns_counters *counters)
{
	struct server *s = NULL;
	struct resolv_resolution *resolution = NULL;
	void *serverip, *firstip;
	short server_sin_family, firstip_sin_family;
	int ret;
	int has_no_ip = 0;

	s = objt_server(requester->owner);
	if (!s)
		return 1;

	if (s->srvrq) {
		/* If DNS resolution is disabled ignore it.
		 * This is the case if the server was associated to
		 * a SRV record and this record is now expired.
		 */
		if (s->flags & SRV_F_NO_RESOLUTION)
			return 1;
	}

	resolution = (s->resolv_requester ? s->resolv_requester->resolution : NULL);
	if (!resolution)
		return 1;

	/* initializing variables */
	firstip = NULL;		/* pointer to the first valid response found */
				/* it will be used as the new IP if a change is required */
	firstip_sin_family = AF_UNSPEC;
	serverip = NULL;	/* current server IP address */

	/* initializing server IP pointer */
	server_sin_family = s->addr.ss_family;
	switch (server_sin_family) {
		case AF_INET:
			serverip = &((struct sockaddr_in *)&s->addr)->sin_addr.s_addr;
			break;

		case AF_INET6:
			serverip = &((struct sockaddr_in6 *)&s->addr)->sin6_addr.s6_addr;
			break;

		case AF_UNSPEC:
			break;

		default:
			goto invalid;
	}

	ret = resolv_get_ip_from_response(&resolution->response, &s->resolv_opts,
	                                  serverip, server_sin_family, &firstip,
	                                  &firstip_sin_family, s);

	switch (ret) {
		case RSLV_UPD_NO:
			goto update_status;

		case RSLV_UPD_SRVIP_NOT_FOUND:
			goto save_ip;

		case RSLV_UPD_NO_IP_FOUND:
			has_no_ip = 1;
			goto update_status;

		default:
			has_no_ip = 1;
			goto invalid;

	}

 save_ip:
	if (counters) {
		counters->app.resolver.update++;
		/* save the first ip we found */
		srv_update_addr(s, firstip, firstip_sin_family,
		                SERVER_INETADDR_UPDATER_DNS_RESOLVER(counters->ns_puid));
	}
	else
		srv_update_addr(s, firstip, firstip_sin_family, SERVER_INETADDR_UPDATER_DNS_CACHE);

 update_status:
	if (has_no_ip && !snr_set_srv_down(s)) {
		struct server_inetaddr srv_addr;

		/* unset server's addr, keep port */
		server_get_inetaddr(s, &srv_addr);
		memset(&srv_addr.addr, 0, sizeof(srv_addr.addr));
		server_set_inetaddr(s, &srv_addr, SERVER_INETADDR_UPDATER_NONE, NULL);
	}
	return 1;

 invalid:
	if (counters) {
		counters->app.resolver.invalid++;
		goto update_status;
	}
	if (has_no_ip && !snr_set_srv_down(s)) {
		struct server_inetaddr srv_addr;

		/* unset server's addr, keep port */
		server_get_inetaddr(s, &srv_addr);
		memset(&srv_addr.addr, 0, sizeof(srv_addr.addr));
		server_set_inetaddr(s, &srv_addr, SERVER_INETADDR_UPDATER_NONE, NULL);
	}
	return 0;
}

/*
 * SRV record error management callback
 * returns:
 *  0 if we can trash answser items.
 *  1 when safely ignored and we must kept answer items
 *
 * Grabs the server's lock.
 */
int srvrq_resolution_error_cb(struct resolv_requester *requester, int error_code)
{
	struct resolv_srvrq *srvrq;
	struct resolv_resolution *res;
	struct resolvers *resolvers;
	int exp;

	/* SRV records */
	srvrq = objt_resolv_srvrq(requester->owner);
	if (!srvrq)
		return 0;

	resolvers = srvrq->resolvers;
	res = requester->resolution;

	switch (res->status) {

		case RSLV_STATUS_NX:
			/* stop server if resolution is NX for a long enough period */
			exp = tick_add(res->last_valid, resolvers->hold.nx);
			if (!tick_is_expired(exp, now_ms))
				return 1;
			break;

		case RSLV_STATUS_TIMEOUT:
			/* stop server if resolution is TIMEOUT for a long enough period */
			exp = tick_add(res->last_valid, resolvers->hold.timeout);
			if (!tick_is_expired(exp, now_ms))
				return 1;
			break;

		case RSLV_STATUS_REFUSED:
			/* stop server if resolution is REFUSED for a long enough period */
			exp = tick_add(res->last_valid, resolvers->hold.refused);
			if (!tick_is_expired(exp, now_ms))
				return 1;
			break;

		default:
			/* stop server if resolution failed for a long enough period */
			exp = tick_add(res->last_valid, resolvers->hold.other);
			if (!tick_is_expired(exp, now_ms))
				return 1;
	}

	/* Remove any associated server ref */
	resolv_detach_from_resolution_answer_items(res,  requester);

	return 0;
}

/*
 * Server Name Resolution error management callback
 * returns:
 *  0 if we can trash answser items.
 *  1 when safely ignored and we must kept answer items
 *
 * Grabs the server's lock.
 */
int snr_resolution_error_cb(struct resolv_requester *requester, int error_code)
{
	struct server *s;

	s = objt_server(requester->owner);
	if (!s)
		return 0;

	HA_SPIN_LOCK(SERVER_LOCK, &s->lock);
	if (!snr_set_srv_down(s)) {
		struct server_inetaddr srv_addr;

		/* unset server's addr, keep port */
		server_get_inetaddr(s, &srv_addr);
		memset(&srv_addr.addr, 0, sizeof(srv_addr.addr));
		server_set_inetaddr(s, &srv_addr, SERVER_INETADDR_UPDATER_NONE, NULL);
		HA_SPIN_UNLOCK(SERVER_LOCK, &s->lock);
		resolv_detach_from_resolution_answer_items(requester->resolution, requester);
		return 0;
	}
	HA_SPIN_UNLOCK(SERVER_LOCK, &s->lock);

	return 1;
}

/*
 * Function to check if <ip> is already affected to a server in the backend
 * which owns <srv> and is up.
 * It returns a pointer to the first server found or NULL if <ip> is not yet
 * assigned.
 *
 * Must be called with server lock held
 */
struct server *snr_check_ip_callback(struct server *srv, void *ip, unsigned char *ip_family)
{
	struct server *tmpsrv;
	struct proxy *be;

	if (!srv)
		return NULL;

	be = srv->proxy;
	for (tmpsrv = be->srv; tmpsrv; tmpsrv = tmpsrv->next) {
		/* we found the current server is the same, ignore it */
		if (srv == tmpsrv)
			continue;

		/* We want to compare the IP in the record with the IP of the servers in the
		 * same backend, only if:
		 *   * DNS resolution is enabled on the server
		 *   * the hostname used for the resolution by our server is the same than the
		 *     one used for the server found in the backend
		 *   * the server found in the backend is not our current server
		 */
		HA_SPIN_LOCK(SERVER_LOCK, &tmpsrv->lock);
		if ((tmpsrv->hostname_dn == NULL) ||
		    (srv->hostname_dn_len != tmpsrv->hostname_dn_len) ||
		    (strcasecmp(srv->hostname_dn, tmpsrv->hostname_dn) != 0) ||
		    (srv->puid == tmpsrv->puid)) {
			HA_SPIN_UNLOCK(SERVER_LOCK, &tmpsrv->lock);
			continue;
		}

		/* If the server has been taken down, don't consider it */
		if (tmpsrv->next_admin & SRV_ADMF_RMAINT) {
			HA_SPIN_UNLOCK(SERVER_LOCK, &tmpsrv->lock);
			continue;
		}

		/* At this point, we have 2 different servers using the same DNS hostname
		 * for their respective resolution.
		 */
		if (*ip_family == tmpsrv->addr.ss_family &&
		    ((tmpsrv->addr.ss_family == AF_INET &&
		      memcmp(ip, &((struct sockaddr_in *)&tmpsrv->addr)->sin_addr, 4) == 0) ||
		     (tmpsrv->addr.ss_family == AF_INET6 &&
		      memcmp(ip, &((struct sockaddr_in6 *)&tmpsrv->addr)->sin6_addr, 16) == 0))) {
			HA_SPIN_UNLOCK(SERVER_LOCK, &tmpsrv->lock);
			return tmpsrv;
		}
		HA_SPIN_UNLOCK(SERVER_LOCK, &tmpsrv->lock);
	}


	return NULL;
}

/* Sets the server's address (srv->addr) from srv->hostname using the libc's
 * resolver. This is suited for initial address configuration. Returns 0 on
 * success otherwise a non-zero error code. In case of error, *err_code, if
 * not NULL, is filled up.
 */
int srv_set_addr_via_libc(struct server *srv, int *err_code)
{
	struct sockaddr_storage new_addr;

	memset(&new_addr, 0, sizeof(new_addr));

	/* Use the preferred family, if configured */
	new_addr.ss_family = srv->addr.ss_family;
	if (str2ip2(srv->hostname, &new_addr, 1) == NULL) {
		if (err_code)
			*err_code |= ERR_WARN;
		return 1;
	}
	_srv_set_inetaddr(srv, &new_addr);
	return 0;
}

/* Set the server's FDQN (->hostname) from <hostname>.
 * Returns -1 if failed, 0 if not.
 *
 * Must be called with the server lock held.
 */
int srv_set_fqdn(struct server *srv, const char *hostname, int resolv_locked)
{
	struct resolv_resolution *resolution;
	char                  *hostname_dn;
	int                    hostname_len, hostname_dn_len;

	/* Note that the server lock is already held. */
	if (!srv->resolvers)
		return -1;

	if (!resolv_locked)
		HA_SPIN_LOCK(DNS_LOCK, &srv->resolvers->lock);
	/* run time DNS/SRV resolution was not active for this server
	 * and we can't enable it at run time for now.
	 */
	if (!srv->resolv_requester && !srv->srvrq)
		goto err;

	chunk_reset(&trash);
	hostname_len    = strlen(hostname);
	hostname_dn     = trash.area;
	hostname_dn_len = resolv_str_to_dn_label(hostname, hostname_len,
	                                         hostname_dn, trash.size);
	if (hostname_dn_len == -1)
		goto err;

	resolution = (srv->resolv_requester ? srv->resolv_requester->resolution : NULL);
	if (resolution &&
	    resolution->hostname_dn &&
	    resolution->hostname_dn_len == hostname_dn_len &&
	    strcasecmp(resolution->hostname_dn, hostname_dn) == 0)
		goto end;

	resolv_unlink_resolution(srv->resolv_requester);

	free(srv->hostname);
	free(srv->hostname_dn);
	srv->hostname        = strdup(hostname);
	srv->hostname_dn     = strdup(hostname_dn);
	srv->hostname_dn_len = hostname_dn_len;
	if (!srv->hostname || !srv->hostname_dn)
		goto err;

	if (srv->flags & SRV_F_NO_RESOLUTION)
		goto end;

	if (resolv_link_resolution(srv, OBJ_TYPE_SERVER, 1) == -1)
		goto err;

  end:
	if (!resolv_locked)
		HA_SPIN_UNLOCK(DNS_LOCK, &srv->resolvers->lock);
	return 0;

  err:
	if (!resolv_locked)
		HA_SPIN_UNLOCK(DNS_LOCK, &srv->resolvers->lock);
	return -1;
}

/* Sets the server's address (srv->addr) from srv->lastaddr which was filled
 * from the state file. This is suited for initial address configuration.
 * Returns 0 on success otherwise a non-zero error code. In case of error,
 * *err_code, if not NULL, is filled up.
 */
static int srv_apply_lastaddr(struct server *srv, int *err_code)
{
	struct sockaddr_storage new_addr;

	memset(&new_addr, 0, sizeof(new_addr));

	/* Use the preferred family, if configured */
	new_addr.ss_family = srv->addr.ss_family;
	if (!str2ip2(srv->lastaddr, &new_addr, 0)) {
		if (err_code)
			*err_code |= ERR_WARN;
		return 1;
	}
	_srv_set_inetaddr(srv, &new_addr);
	return 0;
}

/* returns 0 if no error, otherwise a combination of ERR_* flags */
static int srv_iterate_initaddr(struct server *srv)
{
	char *name = srv->hostname;
	int return_code = 0;
	int err_code;
	unsigned int methods;

	/* If no addr and no hostname set, get the name from the DNS SRV request */
	if (!name && srv->srvrq)
		name = srv->srvrq->name;

	methods = srv->init_addr_methods;
	if (!methods) {
		/* otherwise default to "last,libc" */
		srv_append_initaddr(&methods, SRV_IADDR_LAST);
		srv_append_initaddr(&methods, SRV_IADDR_LIBC);
		if (srv->resolvers_id) {
			/* dns resolution is configured, add "none" to not fail on startup */
			srv_append_initaddr(&methods, SRV_IADDR_NONE);
		}
	}

	/* "-dr" : always append "none" so that server addresses resolution
	 * failures are silently ignored, this is convenient to validate some
	 * configs out of their environment.
	 */
	if (global.tune.options & GTUNE_RESOLVE_DONTFAIL)
		srv_append_initaddr(&methods, SRV_IADDR_NONE);

	while (methods) {
		err_code = 0;
		switch (srv_get_next_initaddr(&methods)) {
		case SRV_IADDR_LAST:
			if (!srv->lastaddr)
				continue;
			if (srv_apply_lastaddr(srv, &err_code) == 0)
				goto out;
			return_code |= err_code;
			break;

		case SRV_IADDR_LIBC:
			if (!srv->hostname)
				continue;
			if (srv_set_addr_via_libc(srv, &err_code) == 0)
				goto out;
			return_code |= err_code;
			break;

		case SRV_IADDR_NONE:
			srv_set_admin_flag(srv, SRV_ADMF_RMAINT, SRV_ADM_STCHGC_NONE);
			if (return_code) {
				ha_notice("could not resolve address '%s', disabling server.\n",
					  name);
			}
			return return_code;

		case SRV_IADDR_IP:
			_srv_set_inetaddr(srv, &srv->init_addr);
			if (return_code) {
				ha_warning("could not resolve address '%s', falling back to configured address.\n",
					   name);
			}
			goto out;

		default: /* unhandled method */
			break;
		}
	}

	if (!return_code)
		ha_alert("no method found to resolve address '%s'.\n", name);
	else
		ha_alert("could not resolve address '%s'.\n", name);

	return_code |= ERR_ALERT | ERR_FATAL;
	return return_code;
out:
	srv_set_dyncookie(srv);
	srv_set_addr_desc(srv, 1);
	return return_code;
}

/*
 * This function parses all backends and all servers within each backend
 * and performs servers' addr resolution based on information provided by:
 *   - configuration file
 *   - server-state file (states provided by an 'old' haproxy process)
 *
 * Returns 0 if no error, otherwise, a combination of ERR_ flags.
 */
int srv_init_addr(void)
{
	struct proxy *curproxy;
	int return_code = 0;

	curproxy = proxies_list;
	while (curproxy) {
		struct server *srv;

		/* servers are in backend only */
		if (!(curproxy->cap & PR_CAP_BE) || (curproxy->flags & (PR_FL_DISABLED|PR_FL_STOPPED)))
			goto srv_init_addr_next;

		for (srv = curproxy->srv; srv; srv = srv->next) {
			set_usermsgs_ctx(srv->conf.file, srv->conf.line, &srv->obj_type);
			if (srv->hostname || srv->srvrq)
				return_code |= srv_iterate_initaddr(srv);
			reset_usermsgs_ctx();
		}

 srv_init_addr_next:
		curproxy = curproxy->next;
	}

	return return_code;
}

/*
 * Must be called with the server lock held.
 */
const char *srv_update_fqdn(struct server *server, const char *fqdn, const char *updater, int resolv_locked)
{

	struct buffer *msg;

	msg = get_trash_chunk();
	chunk_reset(msg);

	if (server->hostname && strcmp(fqdn, server->hostname) == 0) {
		chunk_appendf(msg, "no need to change the FDQN");
		goto out;
	}

	if (strlen(fqdn) > DNS_MAX_NAME_SIZE || invalid_domainchar(fqdn)) {
		chunk_appendf(msg, "invalid fqdn '%s'", fqdn);
		goto out;
	}

	chunk_appendf(msg, "%s/%s changed its FQDN from %s to %s",
	              server->proxy->id, server->id, server->hostname, fqdn);

	if (srv_set_fqdn(server, fqdn, resolv_locked) < 0) {
		chunk_reset(msg);
		chunk_appendf(msg, "could not update %s/%s FQDN",
		              server->proxy->id, server->id);
		goto out;
	}

	/* Flag as FQDN set from stats socket. */
	server->next_admin |= SRV_ADMF_HMAINT;

 out:
	if (updater)
		chunk_appendf(msg, " by '%s'", updater);
	chunk_appendf(msg, "\n");

	return msg->area;
}


/* Expects to find a backend and a server in <arg> under the form <backend>/<server>,
 * and returns the pointer to the server. Otherwise, display adequate error messages
 * on the CLI, sets the CLI's state to CLI_ST_PRINT and returns NULL. This is only
 * used for CLI commands requiring a server name.
 * Important: the <arg> is modified to remove the '/'.
 */
struct server *cli_find_server(struct appctx *appctx, char *arg)
{
	struct proxy *px;
	struct server *sv;
	struct ist be_name, sv_name = ist(arg);

	be_name = istsplit(&sv_name, '/');
	if (!istlen(sv_name)) {
		cli_err(appctx, "Require 'backend/server'.\n");
		return NULL;
	}

	if (!(px = proxy_be_by_name(ist0(be_name)))) {
		cli_err(appctx, "No such backend.\n");
		return NULL;
	}
	if (!(sv = server_find_by_name(px, ist0(sv_name)))) {
		cli_err(appctx, "No such server.\n");
		return NULL;
	}

	if (px->flags & (PR_FL_DISABLED|PR_FL_STOPPED)) {
		cli_err(appctx, "Proxy is disabled.\n");
		return NULL;
	}

	return sv;
}


/* grabs the server lock */
static int cli_parse_set_server(char **args, char *payload, struct appctx *appctx, void *private)
{
	struct server *sv;
	const char *warning;

	if (!cli_has_level(appctx, ACCESS_LVL_ADMIN))
		return 1;

	sv = cli_find_server(appctx, args[2]);
	if (!sv)
		return 1;

	if (strcmp(args[3], "weight") == 0) {
		HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
		warning = server_parse_weight_change_request(sv, args[4]);
		HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
		if (warning)
			cli_err(appctx, warning);
	}
	else if (strcmp(args[3], "state") == 0) {
		HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
		if (strcmp(args[4], "ready") == 0)
			srv_adm_set_ready(sv);
		else if (strcmp(args[4], "drain") == 0)
			srv_adm_set_drain(sv);
		else if (strcmp(args[4], "maint") == 0)
			srv_adm_set_maint(sv);
		else
			cli_err(appctx, "'set server <srv> state' expects 'ready', 'drain' and 'maint'.\n");
		HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
	}
	else if (strcmp(args[3], "health") == 0) {
		HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
		if (sv->track)
			cli_err(appctx, "cannot change health on a tracking server.\n");
		else if (strcmp(args[4], "up") == 0) {
			sv->check.health = sv->check.rise + sv->check.fall - 1;
			srv_set_running(sv, SRV_OP_STCHGC_CLI);
		}
		else if (strcmp(args[4], "stopping") == 0) {
			sv->check.health = sv->check.rise + sv->check.fall - 1;
			srv_set_stopping(sv, SRV_OP_STCHGC_CLI);
		}
		else if (strcmp(args[4], "down") == 0) {
			sv->check.health = 0;
			srv_set_stopped(sv, SRV_OP_STCHGC_CLI);
		}
		else
			cli_err(appctx, "'set server <srv> health' expects 'up', 'stopping', or 'down'.\n");
		HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
	}
	else if (strcmp(args[3], "agent") == 0) {
		HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
		if (!(sv->agent.state & CHK_ST_ENABLED))
			cli_err(appctx, "agent checks are not enabled on this server.\n");
		else if (strcmp(args[4], "up") == 0) {
			sv->agent.health = sv->agent.rise + sv->agent.fall - 1;
			srv_set_running(sv, SRV_OP_STCHGC_CLI);
		}
		else if (strcmp(args[4], "down") == 0) {
			sv->agent.health = 0;
			srv_set_stopped(sv, SRV_OP_STCHGC_CLI);
		}
		else
			cli_err(appctx, "'set server <srv> agent' expects 'up' or 'down'.\n");
		HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
	}
	else if (strcmp(args[3], "agent-addr") == 0) {
		char *addr = NULL;
		char *port = NULL;
		if (strlen(args[4]) == 0) {
			cli_err(appctx, "set server <b>/<s> agent-addr requires"
					" an address and optionally a port.\n");
			goto out;
		}
		addr = args[4];
		if (strcmp(args[5], "port") == 0)
			port = args[6];
		HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
		warning = srv_update_agent_addr_port(sv, addr, port);
		HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
		if (warning)
			cli_msg(appctx, LOG_WARNING, warning);
	}
	else if (strcmp(args[3], "agent-port") == 0) {
		char *port = NULL;
		if (strlen(args[4]) == 0) {
			cli_err(appctx, "set server <b>/<s> agent-port requires"
					" a port.\n");
			goto out;
		}
		port = args[4];
		HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
		warning = srv_update_agent_addr_port(sv, NULL, port);
		HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
		if (warning)
			cli_msg(appctx, LOG_WARNING, warning);
	}
	else if (strcmp(args[3], "agent-send") == 0) {
		HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
		if (!(sv->agent.state & CHK_ST_ENABLED))
			cli_err(appctx, "agent checks are not enabled on this server.\n");
		else {
			if (!set_srv_agent_send(sv, args[4]))
				cli_err(appctx, "cannot allocate memory for new string.\n");
		}
		HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
	}
	else if (strcmp(args[3], "check-addr") == 0) {
		char *addr = NULL;
		char *port = NULL;
		if (strlen(args[4]) == 0) {
			cli_err(appctx, "set server <b>/<s> check-addr requires"
					" an address and optionally a port.\n");
			goto out;
		}
		addr = args[4];
		if (strcmp(args[5], "port") == 0)
			port = args[6];
		HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
		warning = srv_update_check_addr_port(sv, addr, port);
		HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
		if (warning)
			cli_msg(appctx, LOG_WARNING, warning);
	}
	else if (strcmp(args[3], "check-port") == 0) {
		char *port = NULL;
		if (strlen(args[4]) == 0) {
			cli_err(appctx, "set server <b>/<s> check-port requires"
					" a port.\n");
			goto out;
		}
		port = args[4];
		HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
		warning = srv_update_check_addr_port(sv, NULL, port);
		HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
		if (warning)
			cli_msg(appctx, LOG_WARNING, warning);
	}
	else if (strcmp(args[3], "addr") == 0) {
		char *addr = NULL;
		char *port = NULL;
		if (strlen(args[4]) == 0) {
			cli_err(appctx, "set server <b>/<s> addr requires an address and optionally a port.\n");
			goto out;
		}
		else {
			addr = args[4];
		}
		if (strcmp(args[5], "port") == 0) {
			port = args[6];
		}
		HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
		warning = srv_update_addr_port(sv, addr, port, SERVER_INETADDR_UPDATER_CLI);
		if (warning)
			cli_msg(appctx, LOG_WARNING, warning);
		HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
	}
	else if (strcmp(args[3], "fqdn") == 0) {
		if (!*args[4]) {
			cli_err(appctx, "set server <b>/<s> fqdn requires a FQDN.\n");
			goto out;
		}
		if (!sv->resolvers) {
			cli_err(appctx, "set server <b>/<s> fqdn failed because no resolution is configured.\n");
			goto out;
		}
		if (sv->srvrq) {
			cli_err(appctx, "set server <b>/<s> fqdn failed because SRV resolution is configured.\n");
			goto out;
		}
		HA_SPIN_LOCK(DNS_LOCK, &sv->resolvers->lock);
		HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
		/* ensure runtime resolver will process this new fqdn */
		if (sv->flags & SRV_F_NO_RESOLUTION) {
			sv->flags &= ~SRV_F_NO_RESOLUTION;
		}
		warning = srv_update_fqdn(sv, args[4], "stats socket command", 1);
		HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
		HA_SPIN_UNLOCK(DNS_LOCK, &sv->resolvers->lock);
		if (warning)
			cli_msg(appctx, LOG_WARNING, warning);
	}
	else if (strcmp(args[3], "ssl") == 0) {
#ifdef USE_OPENSSL
		if (sv->flags & SRV_F_DYNAMIC) {
			cli_err(appctx, "'set server <srv> ssl' not supported on dynamic servers\n");
			goto out;
		}

		if (sv->ssl_ctx.ctx == NULL) {
			cli_err(appctx, "'set server <srv> ssl' cannot be set. "
					" default-server should define ssl settings\n");
			goto out;
		}

		HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
		if (strcmp(args[4], "on") == 0) {
			srv_set_ssl(sv, 1);
		} else if (strcmp(args[4], "off") == 0) {
			srv_set_ssl(sv, 0);
		} else {
			HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
			cli_err(appctx, "'set server <srv> ssl' expects 'on' or 'off'.\n");
			goto out;
		}
		srv_cleanup_connections(sv);
		HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
		cli_msg(appctx, LOG_NOTICE, "server ssl setting updated.\n");
#else
		cli_msg(appctx, LOG_NOTICE, "server ssl setting not supported.\n");
#endif
	} else {
		cli_err(appctx,
			"usage: set server <backend>/<server> "
			"addr | agent | agent-addr | agent-port | agent-send | "
			"check-addr | check-port | fqdn | health | ssl | "
			"state | weight\n");
	}
 out:
	return 1;
}

static int cli_parse_get_weight(char **args, char *payload, struct appctx *appctx, void *private)
{
	struct proxy *be;
	struct server *sv;
	struct ist be_name, sv_name = ist(args[2]);

	be_name = istsplit(&sv_name, '/');
	if (!istlen(sv_name))
		return cli_err(appctx, "Require 'backend/server'.\n");

	if (!(be = proxy_be_by_name(ist0(be_name))))
		return cli_err(appctx, "No such backend.\n");
	if (!(sv = server_find_by_name(be, ist0(sv_name))))
		return cli_err(appctx, "No such server.\n");

	/* return server's effective weight at the moment */
	snprintf(trash.area, trash.size, "%d (initial %d)\n", sv->uweight,
		 sv->iweight);
	if (applet_putstr(appctx, trash.area) == -1)
		return 0;
	return 1;
}

/* Parse a "set weight" command.
 *
 * Grabs the server lock.
 */
static int cli_parse_set_weight(char **args, char *payload, struct appctx *appctx, void *private)
{
	struct server *sv;
	const char *warning;

	if (!cli_has_level(appctx, ACCESS_LVL_ADMIN))
		return 1;

	sv = cli_find_server(appctx, args[2]);
	if (!sv)
		return 1;

	HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);

	warning = server_parse_weight_change_request(sv, args[3]);
	if (warning)
		cli_err(appctx, warning);

	HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);

	return 1;
}

/* parse a "set maxconn server" command. It always returns 1.
 *
 * Grabs the server lock.
 */
static int cli_parse_set_maxconn_server(char **args, char *payload, struct appctx *appctx, void *private)
{
	struct server *sv;
	const char *warning;

	if (!cli_has_level(appctx, ACCESS_LVL_ADMIN))
		return 1;

	sv = cli_find_server(appctx, args[3]);
	if (!sv)
		return 1;

	HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);

	warning = server_parse_maxconn_change_request(sv, args[4]);
	if (warning)
		cli_err(appctx, warning);

	HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);

	return 1;
}

/* parse a "disable agent" command. It always returns 1.
 *
 * Grabs the server lock.
 */
static int cli_parse_disable_agent(char **args, char *payload, struct appctx *appctx, void *private)
{
	struct server *sv;

	if (!cli_has_level(appctx, ACCESS_LVL_ADMIN))
		return 1;

	sv = cli_find_server(appctx, args[2]);
	if (!sv)
		return 1;

	HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
	sv->agent.state &= ~CHK_ST_ENABLED;
	HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
	return 1;
}

/* parse a "disable health" command. It always returns 1.
 *
 * Grabs the server lock.
 */
static int cli_parse_disable_health(char **args, char *payload, struct appctx *appctx, void *private)
{
	struct server *sv;

	if (!cli_has_level(appctx, ACCESS_LVL_ADMIN))
		return 1;

	sv = cli_find_server(appctx, args[2]);
	if (!sv)
		return 1;

	HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
	sv->check.state &= ~CHK_ST_ENABLED;
	HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
	return 1;
}

/* parse a "disable server" command. It always returns 1.
 *
 * Grabs the server lock.
 */
static int cli_parse_disable_server(char **args, char *payload, struct appctx *appctx, void *private)
{
	struct server *sv;

	if (!cli_has_level(appctx, ACCESS_LVL_ADMIN))
		return 1;

	sv = cli_find_server(appctx, args[2]);
	if (!sv)
		return 1;

	HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
	srv_adm_set_maint(sv);
	HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
	return 1;
}

/* parse a "enable agent" command. It always returns 1.
 *
 * Grabs the server lock.
 */
static int cli_parse_enable_agent(char **args, char *payload, struct appctx *appctx, void *private)
{
	struct server *sv;

	if (!cli_has_level(appctx, ACCESS_LVL_ADMIN))
		return 1;

	sv = cli_find_server(appctx, args[2]);
	if (!sv)
		return 1;

	if (!(sv->agent.state & CHK_ST_CONFIGURED))
		return cli_err(appctx, "Agent was not configured on this server, cannot enable.\n");

	HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
	sv->agent.state |= CHK_ST_ENABLED;
	HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
	return 1;
}

/* parse a "enable health" command. It always returns 1.
 *
 * Grabs the server lock.
 */
static int cli_parse_enable_health(char **args, char *payload, struct appctx *appctx, void *private)
{
	struct server *sv;

	if (!cli_has_level(appctx, ACCESS_LVL_ADMIN))
		return 1;

	sv = cli_find_server(appctx, args[2]);
	if (!sv)
		return 1;

	if (!(sv->check.state & CHK_ST_CONFIGURED))
		return cli_err(appctx, "Health check was not configured on this server, cannot enable.\n");

	HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
	sv->check.state |= CHK_ST_ENABLED;
	HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
	return 1;
}

/* parse a "enable server" command. It always returns 1.
 *
 * Grabs the server lock.
 */
static int cli_parse_enable_server(char **args, char *payload, struct appctx *appctx, void *private)
{
	struct server *sv;

	if (!cli_has_level(appctx, ACCESS_LVL_ADMIN))
		return 1;

	sv = cli_find_server(appctx, args[2]);
	if (!sv)
		return 1;

	HA_SPIN_LOCK(SERVER_LOCK, &sv->lock);
	srv_adm_set_ready(sv);
	if (!(sv->flags & SRV_F_COOKIESET)
	    && (sv->proxy->ck_opts & PR_CK_DYNAMIC) &&
	    sv->cookie)
		srv_check_for_dup_dyncookie(sv);
	HA_SPIN_UNLOCK(SERVER_LOCK, &sv->lock);
	return 1;
}

/* Allocates data structure related to load balancing for the server <sv>. It
 * is only required for dynamic servers.
 *
 * At the moment, the server lock is not used as this function is only called
 * for a dynamic server not yet registered.
 *
 * Returns 1 on success, 0 on allocation failure.
 */
static int srv_alloc_lb(struct server *sv, struct proxy *be)
{
	int node;

	sv->lb_tree = (sv->flags & SRV_F_BACKUP) ?
	              &be->lbprm.chash.bck : &be->lbprm.chash.act;
	sv->lb_nodes_tot = sv->uweight * BE_WEIGHT_SCALE;
	sv->lb_nodes_now = 0;

	if (((be->lbprm.algo & (BE_LB_KIND | BE_LB_PARM)) == (BE_LB_KIND_RR | BE_LB_RR_RANDOM)) ||
	    ((be->lbprm.algo & (BE_LB_KIND | BE_LB_HASH_TYPE)) == (BE_LB_KIND_HI | BE_LB_HASH_CONS))) {
		sv->lb_nodes = calloc(sv->lb_nodes_tot, sizeof(*sv->lb_nodes));

		if (!sv->lb_nodes)
			return 0;

		for (node = 0; node < sv->lb_nodes_tot; node++) {
			sv->lb_nodes[node].server = sv;
			sv->lb_nodes[node].node.key = full_hash(sv->puid * SRV_EWGHT_RANGE + node);
		}
	}

	return 1;
}

/* updates the server's weight during a warmup stage. Once the final weight is
 * reached, the task automatically stops. Note that any server status change
 * must have updated s->counters.last_change accordingly.
 */
static struct task *server_warmup(struct task *t, void *context, unsigned int state)
{
	struct server *s = context;

	/* by default, plan on stopping the task */
	t->expire = TICK_ETERNITY;
	if ((s->next_admin & SRV_ADMF_MAINT) ||
	    (s->next_state != SRV_ST_STARTING))
		return t;

	HA_SPIN_LOCK(SERVER_LOCK, &s->lock);

	/* recalculate the weights and update the state */
	server_recalc_eweight(s, 1);

	/* probably that we can refill this server with a bit more connections */
	pendconn_grab_from_px(s);

	HA_SPIN_UNLOCK(SERVER_LOCK, &s->lock);

	/* get back there in 1 second or 1/20th of the slowstart interval,
	 * whichever is greater, resulting in small 5% steps.
	 */
	if (s->next_state == SRV_ST_STARTING)
		t->expire = tick_add(now_ms, MS_TO_TICKS(MAX(1000, s->slowstart / 20)));
	return t;
}

/* Allocate the slowstart task if the server is configured with a slowstart
 * timer. If server next_state is SRV_ST_STARTING, the task is scheduled.
 *
 * Returns 0 on success else non-zero.
 */
static int init_srv_slowstart(struct server *srv)
{
	struct task *t;

	if (srv->slowstart) {
		if ((t = task_new_anywhere()) == NULL) {
			ha_alert("Cannot activate slowstart for server %s/%s: out of memory.\n", srv->proxy->id, srv->id);
			return ERR_ALERT | ERR_FATAL;
		}

		/* We need a warmup task that will be called when the server
		 * state switches from down to up.
		 */
		srv->warmup = t;
		t->process = server_warmup;
		t->context = srv;

		/* server can be in this state only because of */
		if (srv->next_state == SRV_ST_STARTING) {
			task_schedule(srv->warmup,
			              tick_add(now_ms,
			                       MS_TO_TICKS(MAX(1000, (ns_to_sec(now_ns) - srv->counters.last_change)) / 20)));
		}
	}

	return ERR_NONE;
}
REGISTER_POST_SERVER_CHECK(init_srv_slowstart);

/* Memory allocation and initialization of the per_thr field.
 * Returns 0 if the field has been successfully initialized, -1 on failure.
 */
int srv_init_per_thr(struct server *srv)
{
	int i;

	srv->per_thr = calloc(global.nbthread, sizeof(*srv->per_thr));
	srv->per_tgrp = calloc(global.nbtgroups, sizeof(*srv->per_tgrp));
	if (!srv->per_thr || !srv->per_tgrp)
		return -1;

	for (i = 0; i < global.nbthread; i++) {
		srv->per_thr[i].idle_conns = EB_ROOT;
		srv->per_thr[i].safe_conns = EB_ROOT;
		srv->per_thr[i].avail_conns = EB_ROOT;
		MT_LIST_INIT(&srv->per_thr[i].streams);

		LIST_INIT(&srv->per_thr[i].idle_conn_list);
	}

	return 0;
}

/* Parse a "add server" command
 * Returns 0 if the server has been successfully initialized, 1 on failure.
 */
static int cli_parse_add_server(char **args, char *payload, struct appctx *appctx, void *private)
{
	struct proxy *be;
	struct server *srv;
	char *be_name, *sv_name;
	int errcode, argc;
	int next_id;
	const int parse_flags = SRV_PARSE_DYNAMIC|SRV_PARSE_PARSE_ADDR;

	usermsgs_clr("CLI");

	if (!cli_has_level(appctx, ACCESS_LVL_ADMIN))
		return 1;

	++args;

	sv_name = be_name = args[1];
	/* split backend/server arg */
	while (*sv_name && *(++sv_name)) {
		if (*sv_name == '/') {
			*sv_name = '\0';
			++sv_name;
			break;
		}
	}

	if (!*sv_name)
		return cli_err(appctx, "Require 'backend/server'.\n");

	be = proxy_be_by_name(be_name);
	if (!be)
		return cli_err(appctx, "No such backend.\n");

	if (!(be->lbprm.algo & BE_LB_PROP_DYN)) {
		cli_err(appctx, "Backend must use a dynamic load balancing to support dynamic servers.\n");
		return 1;
	}

	if (be->mode == PR_MODE_SYSLOG) {
		cli_err(appctx," Dynamic servers cannot be used with log backends.\n");
		return 1;
	}

	/* At this point, some operations might not be thread-safe anymore. This
	 * might be the case for parsing handlers which were designed to run
	 * only at the starting stage on single-thread mode.
	 *
	 * Activate thread isolation to ensure thread-safety.
	 */
	thread_isolate();

	args[1] = sv_name;
	errcode = _srv_parse_init(&srv, args, &argc, be, parse_flags);
	if (errcode)
		goto out;

	while (*args[argc]) {
		errcode = _srv_parse_kw(srv, args, &argc, be, parse_flags);

		if (errcode)
			goto out;
	}

	errcode = _srv_parse_finalize(args, argc, srv, be, parse_flags);
	if (errcode)
		goto out;

	/* A dynamic server does not currently support resolution.
	 *
	 * Initialize it explicitly to the "none" method to ensure no
	 * resolution will ever be executed.
	 */
	srv->init_addr_methods = SRV_IADDR_NONE;

	if (srv->mux_proto) {
		int proto_mode = conn_pr_mode_to_proto_mode(be->mode);
		const struct mux_proto_list *mux_ent;

		mux_ent = conn_get_best_mux_entry(srv->mux_proto->token, PROTO_SIDE_BE, proto_mode);

		if (!mux_ent || !isteq(mux_ent->token, srv->mux_proto->token)) {
			ha_alert("MUX protocol is not usable for server.\n");
			goto out;
		}
	}

	if (srv_init_per_thr(srv) == -1) {
		ha_alert("failed to allocate per-thread lists for server.\n");
		goto out;
	}

	if (srv->max_idle_conns != 0) {
		srv->curr_idle_thr = calloc(global.nbthread, sizeof(*srv->curr_idle_thr));
		if (!srv->curr_idle_thr) {
			ha_alert("failed to allocate counters for server.\n");
			goto out;
		}
	}

	if (!srv_alloc_lb(srv, be)) {
		ha_alert("Failed to initialize load-balancing data.\n");
		goto out;
	}

	if (!stats_allocate_proxy_counters_internal(&srv->extra_counters,
	                                            COUNTERS_SV,
	                                            STATS_PX_CAP_SRV)) {
		ha_alert("failed to allocate extra counters for server.\n");
		goto out;
	}

	/* ensure minconn/maxconn consistency */
	srv_minmax_conn_apply(srv);

	if (srv->use_ssl == 1 || (srv->proxy->options & PR_O_TCPCHK_SSL) ||
	    srv->check.use_ssl == 1) {
		if (xprt_get(XPRT_SSL) && xprt_get(XPRT_SSL)->prepare_srv) {
			if (xprt_get(XPRT_SSL)->prepare_srv(srv))
				goto out;
		}
	}

	if (srv->trackit) {
		if (srv_apply_track(srv, be))
			goto out;
	}

	/* Init check/agent if configured. The check is manually disabled
	 * because a dynamic server is started in a disable state. It must be
	 * manually activated via a "enable health/agent" command.
	 */
	if (srv->do_check) {
		if (init_srv_check(srv))
			goto out;

		srv->check.state &= ~CHK_ST_ENABLED;
	}

	if (srv->do_agent) {
		if (init_srv_agent_check(srv))
			goto out;

		srv->agent.state &= ~CHK_ST_ENABLED;
	}

	/* Init slowstart if needed. */
	if (init_srv_slowstart(srv))
		goto out;

	/* Attach the server to the end of the proxy linked list. Note that this
	 * operation is not thread-safe so this is executed under thread
	 * isolation.
	 *
	 * If a server with the same name is found, reject the new one.
	 */

	/* TODO use a double-linked list for px->srv */
	if (be->srv) {
		struct server *next = be->srv;

		while (1) {
			/* check for duplicate server */
			if (strcmp(srv->id, next->id) == 0) {
				ha_alert("Already exists a server with the same name in backend.\n");
				goto out;
			}

			if (!next->next)
				break;

			next = next->next;
		}

		next->next = srv;
	}
	else {
		srv->next = be->srv;
		be->srv = srv;
	}

	/* generate the server id if not manually specified */
	if (!srv->puid) {
		next_id = get_next_id(&be->conf.used_server_id, 1);
		if (!next_id) {
			ha_alert("Cannot attach server : no id left in proxy\n");
			goto out;
		}

		srv->conf.id.key = srv->puid = next_id;
	}
	srv->conf.name.key = srv->id;

	/* insert the server in the backend trees */
	eb32_insert(&be->conf.used_server_id, &srv->conf.id);
	ebis_insert(&be->conf.used_server_name, &srv->conf.name);
	/* addr_node.key could be NULL if FQDN resolution is postponed (ie: add server from cli) */
	if (srv->addr_node.key)
		ebis_insert(&be->used_server_addr, &srv->addr_node);

	/* check if LSB bit (odd bit) is set for reuse_cnt */
	if (srv_id_reuse_cnt & 1) {
		/* cnt must be increased */
		srv_id_reuse_cnt++;
	}
	/* srv_id_reuse_cnt is always even at this stage, divide by 2 to
	 * save some space
	 * (sizeof(srv->rid) is half of sizeof(srv_id_reuse_cnt))
	 */
	srv->rid = (srv_id_reuse_cnt) ? (srv_id_reuse_cnt / 2) : 0;

	/* generate new server's dynamic cookie if enabled on backend */
	if (be->ck_opts & PR_CK_DYNAMIC) {
		srv_set_dyncookie(srv);
	}

	/* adding server cannot fail when we reach this:
	 * publishing EVENT_HDL_SUB_SERVER_ADD
	 */
	srv_event_hdl_publish(EVENT_HDL_SUB_SERVER_ADD, srv, 1);

	thread_release();

	/* Start the check task. The server must be fully initialized.
	 *
	 * <srvpos> and <nbcheck> parameters are set to 1 as there should be no
	 * need to randomly spread the task interval for dynamic servers.
	 */
	if (srv->check.state & CHK_ST_CONFIGURED) {
		if (!start_check_task(&srv->check, 0, 1, 1))
			ha_alert("System might be unstable, consider to execute a reload\n");
	}
	if (srv->agent.state & CHK_ST_CONFIGURED) {
		if (!start_check_task(&srv->agent, 0, 1, 1))
			ha_alert("System might be unstable, consider to execute a reload\n");
	}

	if (srv->cklen && be->mode != PR_MODE_HTTP)
		ha_warning("Ignoring cookie as HTTP mode is disabled.\n");

	ha_notice("New server registered.\n");
	cli_umsg(appctx, LOG_INFO);

	return 0;

out:
	if (srv) {
		if (srv->track)
			release_server_track(srv);

		if (srv->check.state & CHK_ST_CONFIGURED)
			free_check(&srv->check);
		if (srv->agent.state & CHK_ST_CONFIGURED)
			free_check(&srv->agent);

		/* remove the server from the proxy linked list */
		_srv_detach(srv);
	}

	thread_release();

	if (!usermsgs_empty())
		cli_umsgerr(appctx);

	if (srv)
		srv_drop(srv);

	return 1;
}

/* Check if the server <bename>/<svname> exists and is ready for being deleted.
 * Both <bename> and <svname> must be valid strings. This must be called under
 * thread isolation. If pb/ps are not null, upon success, the pointer to
 * the backend and server respectively will be put there. If pm is not null,
 * a pointer to an error/success message is returned there (possibly NULL if
 * nothing to say). Returned values:
 *  >0 if OK
 *   0 if not yet (should wait if it can)
 *  <0 if not possible
 */
int srv_check_for_deletion(const char *bename, const char *svname, struct proxy **pb, struct server **ps, const char **pm)
{
	struct server *srv = NULL;
	struct proxy *be = NULL;
	const char *msg = NULL;
	int ret;

	/* First, unrecoverable errors */
	ret = -1;

	if (!(be = proxy_be_by_name(bename))) {
		msg = "No such backend.";
		goto leave;
	}

	if (!(srv = server_find_by_name(be, svname))) {
		msg = "No such server.";
		goto leave;
	}

	if (srv->flags & SRV_F_NON_PURGEABLE) {
		msg = "This server cannot be removed at runtime due to other configuration elements pointing to it.";
		goto leave;
	}

	/* Only servers in maintenance can be deleted. This ensures that the
	 * server is not present anymore in the lb structures (through
	 * lbprm.set_server_status_down).
	 */
	if (!(srv->cur_admin & SRV_ADMF_MAINT)) {
		msg = "Only servers in maintenance mode can be deleted.";
		goto leave;
	}

	/* Second, conditions that may change over time */
	ret = 0;

	/* Ensure that there is no active/pending connection on the server. */
	if (srv->curr_used_conns ||
	    !eb_is_empty(&srv->queue.head) || srv_has_streams(srv)) {
		msg = "Server still has connections attached to it, cannot remove it.";
		goto leave;
	}

	/* OK, let's go */
	ret = 1;
leave:
	if (pb)
		*pb = be;
	if (ps)
		*ps = srv;
	if (pm)
		*pm = msg;
	return ret;
}

/* Parse a "del server" command
 * Returns 0 if the server has been successfully initialized, 1 on failure.
 */
static int cli_parse_delete_server(char **args, char *payload, struct appctx *appctx, void *private)
{
	struct proxy *be;
	struct server *srv;
	struct server *prev_del;
	struct ist be_name, sv_name;
	struct mt_list *elt1, elt2;
	struct sess_priv_conns *sess_conns = NULL;
	const char *msg;
	int ret, i;

	if (!cli_has_level(appctx, ACCESS_LVL_ADMIN))
		return 1;

	++args;

	/* The proxy servers list is currently not protected by a lock so this
	 * requires thread isolation. In addition, any place referencing the
	 * server about to be deleted would be unsafe after our operation, so
	 * we must be certain to be alone so that no other thread has even
	 * started to grab a temporary reference to this server.
	 */
	thread_isolate_full();

	sv_name = ist(args[1]);
	be_name = istsplit(&sv_name, '/');
	if (!istlen(sv_name)) {
		cli_err(appctx, "Require 'backend/server'.\n");
		goto out;
	}

	ret = srv_check_for_deletion(ist0(be_name), ist0(sv_name), &be, &srv, &msg);
	if (ret <= 0) {
		/* failure (recoverable or not) */
		cli_err(appctx, msg);
		goto out;
	}

	/* Close idle connections attached to this server. */
	for (i = tid;;) {
		struct list *list = &srv->per_thr[i].idle_conn_list;
		struct connection *conn;

		while (!LIST_ISEMPTY(list)) {
			conn = LIST_ELEM(list->n, struct connection *, idle_list);
			if (i != tid) {
				if (conn->mux && conn->mux->takeover)
					conn->mux->takeover(conn, i, 1);
				else if (conn->xprt && conn->xprt->takeover)
					conn->xprt->takeover(conn, conn->ctx, i, 1);
			}
			conn_release(conn);
		}

		/* Also remove all purgeable conns as some of them may still
		 * reference the currently deleted server.
		 */
		while ((conn = MT_LIST_POP(&idle_conns[i].toremove_conns,
		                           struct connection *, toremove_list))) {
			conn_release(conn);
		}

		if ((i = ((i + 1 == global.nbthread) ? 0 : i + 1)) == tid)
			break;
	}

	/* All idle connections should be removed now. */
	BUG_ON(srv->curr_idle_conns);

	/* Close idle private connections attached to this server. */
	mt_list_for_each_entry_safe(sess_conns, &srv->sess_conns, srv_el, elt1, elt2) {
		struct connection *conn, *conn_back;
		list_for_each_entry_safe(conn, conn_back, &sess_conns->conn_list, sess_el) {

			/* Only idle connections should be present if srv_check_for_deletion() is true. */
			BUG_ON(!(conn->flags & CO_FL_SESS_IDLE));

			LIST_DEL_INIT(&conn->sess_el);
			conn->owner = NULL;
			conn->flags &= ~CO_FL_SESS_IDLE;
			if (sess_conns->tid != tid) {
				if (conn->mux && conn->mux->takeover)
					conn->mux->takeover(conn, sess_conns->tid, 1);
				else if (conn->xprt && conn->xprt->takeover)
					conn->xprt->takeover(conn, conn->ctx, sess_conns->tid, 1);
			}
			conn_release(conn);
		}

		LIST_DELETE(&sess_conns->sess_el);
		MT_LIST_DELETE_SAFE(elt1);
		pool_free(pool_head_sess_priv_conns, sess_conns);
	}

	/* removing cannot fail anymore when we reach this:
	 * publishing EVENT_HDL_SUB_SERVER_DEL
	 */
	srv_event_hdl_publish(EVENT_HDL_SUB_SERVER_DEL, srv, 1);

	/* remove srv from tracking list */
	if (srv->track)
		release_server_track(srv);

	/* stop the check task if running */
	if (srv->check.state & CHK_ST_CONFIGURED)
		check_purge(&srv->check);
	if (srv->agent.state & CHK_ST_CONFIGURED)
		check_purge(&srv->agent);

	/* detach the server from the proxy linked list
	 * The proxy servers list is currently not protected by a lock, so this
	 * requires thread_isolate/release.
	 */
	_srv_detach(srv);

	/* Some deleted servers could still point to us using their 'next',
	 * update them as needed
	 * Please note the small race between the POP and APPEND, although in
	 * this situation this is not an issue as we are under full thread
	 * isolation
	 */
	while ((prev_del = MT_LIST_POP(&srv->prev_deleted, struct server *, prev_deleted))) {
		/* update its 'next' ptr */
		prev_del->next = srv->next;
		if (srv->next) {
			/* now it is our 'next' responsibility */
			MT_LIST_APPEND(&srv->next->prev_deleted, &prev_del->prev_deleted);
		}
	}

	/* we ourselves need to inform our 'next' that we will still point it */
	if (srv->next)
		MT_LIST_APPEND(&srv->next->prev_deleted, &srv->prev_deleted);

	/* remove srv from addr_node tree */
	eb32_delete(&srv->conf.id);
	ebpt_delete(&srv->conf.name);
	if (srv->addr_node.key)
		ebpt_delete(&srv->addr_node);

	/* remove srv from idle_node tree for idle conn cleanup */
	eb32_delete(&srv->idle_node);

	/* flag the server as deleted
	 * (despite the server being removed from primary server list,
	 * one could still access the server data from a valid ptr)
	 * Deleted flag helps detecting when a server is in transient removal
	 * state.
	 * ie: removed from the list but not yet freed/purged from memory.
	 */
	srv->flags |= SRV_F_DELETED;

	/* set LSB bit (odd bit) for reuse_cnt */
	srv_id_reuse_cnt |= 1;

	thread_release();

	ha_notice("Server deleted.\n");
	srv_drop(srv);

	cli_msg(appctx, LOG_INFO, "Server deleted.\n");
	return 0;

out:
	thread_release();
	return 1;
}

/* register cli keywords */
static struct cli_kw_list cli_kws = {{ },{
	{ { "disable", "agent",  NULL },         "disable agent                           : disable agent checks",                                        cli_parse_disable_agent, NULL },
	{ { "disable", "health",  NULL },        "disable health                          : disable health checks",                                       cli_parse_disable_health, NULL },
	{ { "disable", "server",  NULL },        "disable server (DEPRECATED)             : disable a server for maintenance (use 'set server' instead)", cli_parse_disable_server, NULL },
	{ { "enable", "agent",  NULL },          "enable agent                            : enable agent checks",                                         cli_parse_enable_agent, NULL },
	{ { "enable", "health",  NULL },         "enable health                           : enable health checks",                                        cli_parse_enable_health, NULL },
	{ { "enable", "server",  NULL },         "enable server  (DEPRECATED)             : enable a disabled server (use 'set server' instead)",         cli_parse_enable_server, NULL },
	{ { "set", "maxconn", "server",  NULL }, "set maxconn server <bk>/<srv>           : change a server's maxconn setting",                           cli_parse_set_maxconn_server, NULL },
	{ { "set", "server", NULL },             "set server <bk>/<srv> [opts]            : change a server's state, weight, address or ssl",             cli_parse_set_server },
	{ { "get", "weight", NULL },             "get weight <bk>/<srv>                   : report a server's current weight",                            cli_parse_get_weight },
	{ { "set", "weight", NULL },             "set weight <bk>/<srv>  (DEPRECATED)     : change a server's weight (use 'set server' instead)",         cli_parse_set_weight },
	{ { "add", "server", NULL },             "add server <bk>/<srv>                   : create a new server",                                         cli_parse_add_server, NULL },
	{ { "del", "server", NULL },             "del server <bk>/<srv>                   : remove a dynamically added server",                           cli_parse_delete_server, NULL },
	{{},}
}};

INITCALL1(STG_REGISTER, cli_register_kw, &cli_kws);

/* Prepare a server <srv> to track check status of another one. <srv>.<trackit>
 * field is used to retrieve the identifier of the tracked server, either with
 * the format "proxy/server" or just "server". <curproxy> must point to the
 * backend owning <srv>; if no proxy is specified in <trackit>, it will be used
 * to find the tracked server.
 *
 * Returns 0 if the server track has been activated else non-zero.
 *
 * Not thread-safe.
 */
int srv_apply_track(struct server *srv, struct proxy *curproxy)
{
	struct proxy *px;
	struct server *strack, *loop;
	char *pname, *sname;

	if (!srv->trackit)
		return 1;

	pname = srv->trackit;
	sname = strrchr(pname, '/');

	if (sname) {
		*sname++ = '\0';
	}
	else {
		sname = pname;
		pname = NULL;
	}

	if (pname) {
		px = proxy_be_by_name(pname);
		if (!px) {
			ha_alert("unable to find required proxy '%s' for tracking.\n",
			         pname);
			return 1;
		}
	}
	else {
		px = curproxy;
	}

	strack = findserver(px, sname);
	if (!strack) {
		ha_alert("unable to find required server '%s' for tracking.\n",
		         sname);
		return 1;
	}

	if (strack->flags & SRV_F_DYNAMIC) {
		ha_alert("unable to use %s/%s for tracking as it is a dynamic server.\n",
		         px->id, strack->id);
		return 1;
	}

	if (!strack->do_check && !strack->do_agent && !strack->track &&
	    !strack->trackit) {
		ha_alert("unable to use %s/%s for "
		         "tracking as it does not have any check nor agent enabled.\n",
		         px->id, strack->id);
		return 1;
	}

	for (loop = strack->track; loop && loop != srv; loop = loop->track)
		;

	if (srv == strack || loop) {
		ha_alert("unable to track %s/%s as it "
		         "belongs to a tracking chain looping back to %s/%s.\n",
		         px->id, strack->id, px->id,
		         srv == strack ? strack->id : loop->id);
		return 1;
	}

	if (curproxy != px &&
	    (curproxy->options & PR_O_DISABLE404) != (px->options & PR_O_DISABLE404)) {
		ha_alert("unable to use %s/%s for"
		         "tracking: disable-on-404 option inconsistency.\n",
		         px->id, strack->id);
		return 1;
	}

	srv->track = strack;
	srv->tracknext = strack->trackers;
	strack->trackers = srv;
	strack->flags |= SRV_F_NON_PURGEABLE;

	ha_free(&srv->trackit);

	return 0;
}

/* This function propagates srv state change to lb algorithms */
static void srv_lb_propagate(struct server *s)
{
	struct proxy *px = s->proxy;

	if (px->lbprm.update_server_eweight)
		px->lbprm.update_server_eweight(s);
	else if (srv_willbe_usable(s)) {
		if (px->lbprm.set_server_status_up)
			px->lbprm.set_server_status_up(s);
	}
	else {
		if (px->lbprm.set_server_status_down)
			px->lbprm.set_server_status_down(s);
	}
}

/* directly update server state based on an operational change
 * (compare current and next state to know which transition to apply)
 *
 * The function returns the number of requeued sessions (either taken by
 * the server or redispatched to others servers) due to the server state
 * change.
 */
static int _srv_update_status_op(struct server *s, enum srv_op_st_chg_cause cause)
{
	struct buffer *tmptrash = NULL;
	int log_level;
	int srv_was_stopping = (s->cur_state == SRV_ST_STOPPING) || (s->cur_admin & SRV_ADMF_DRAIN);
	int xferred = 0;

	if ((s->cur_state != SRV_ST_STOPPED) && (s->next_state == SRV_ST_STOPPED)) {
		srv_lb_propagate(s);

		if (s->onmarkeddown & HANA_ONMARKEDDOWN_SHUTDOWNSESSIONS)
			srv_shutdown_streams(s, SF_ERR_DOWN);

		/* we might have streams queued on this server and waiting for
		 * a connection. Those which are redispatchable will be queued
		 * to another server or to the proxy itself.
		 */
		xferred = pendconn_redistribute(s);

		tmptrash = alloc_trash_chunk();
		if (tmptrash) {
			chunk_printf(tmptrash,
			             "%sServer %s/%s is DOWN", s->flags & SRV_F_BACKUP ? "Backup " : "",
			             s->proxy->id, s->id);

			srv_append_op_chg_cause(tmptrash, s, cause);
			srv_append_more(tmptrash, s, xferred, 0);

			ha_warning("%s.\n", tmptrash->area);

			/* we don't send an alert if the server was previously paused */
			log_level = srv_was_stopping ? LOG_NOTICE : LOG_ALERT;
			send_log(s->proxy, log_level, "%s.\n",
				 tmptrash->area);
			send_email_alert(s, log_level, "%s",
					 tmptrash->area);
			free_trash_chunk(tmptrash);
		}
	}
	else if ((s->cur_state != SRV_ST_STOPPING) && (s->next_state == SRV_ST_STOPPING)) {
		srv_lb_propagate(s);

		/* we might have streams queued on this server and waiting for
		 * a connection. Those which are redispatchable will be queued
		 * to another server or to the proxy itself.
		 */
		xferred = pendconn_redistribute(s);

		tmptrash = alloc_trash_chunk();
		if (tmptrash) {
			chunk_printf(tmptrash,
			             "%sServer %s/%s is stopping", s->flags & SRV_F_BACKUP ? "Backup " : "",
			             s->proxy->id, s->id);

			srv_append_op_chg_cause(tmptrash, s, cause);
			srv_append_more(tmptrash, s, xferred, 0);

			ha_warning("%s.\n", tmptrash->area);
			send_log(s->proxy, LOG_NOTICE, "%s.\n",
				 tmptrash->area);
			free_trash_chunk(tmptrash);
		}
	}
	else if (((s->cur_state != SRV_ST_RUNNING) && (s->next_state == SRV_ST_RUNNING))
		 || ((s->cur_state != SRV_ST_STARTING) && (s->next_state == SRV_ST_STARTING))) {

		if (s->next_state == SRV_ST_STARTING && s->warmup)
			task_schedule(s->warmup, tick_add(now_ms, MS_TO_TICKS(MAX(1000, s->slowstart / 20))));

		server_recalc_eweight(s, 0);
		/* now propagate the status change to any LB algorithms */
		srv_lb_propagate(s);

		/* If the server is set with "on-marked-up shutdown-backup-sessions",
		 * and it's not a backup server and its effective weight is > 0,
		 * then it can accept new connections, so we shut down all streams
		 * on all backup servers.
		 */
		if ((s->onmarkedup & HANA_ONMARKEDUP_SHUTDOWNBACKUPSESSIONS) &&
		    !(s->flags & SRV_F_BACKUP) && s->next_eweight)
			srv_shutdown_backup_streams(s->proxy, SF_ERR_UP);

		/* check if we can handle some connections queued at the proxy. We
		 * will take as many as we can handle.
		 */
		xferred = pendconn_grab_from_px(s);

		tmptrash = alloc_trash_chunk();
		if (tmptrash) {
			chunk_printf(tmptrash,
			             "%sServer %s/%s is UP", s->flags & SRV_F_BACKUP ? "Backup " : "",
			             s->proxy->id, s->id);

			srv_append_op_chg_cause(tmptrash, s, cause);
			srv_append_more(tmptrash, s, xferred, 0);

			ha_warning("%s.\n", tmptrash->area);
			send_log(s->proxy, LOG_NOTICE, "%s.\n",
				 tmptrash->area);
			send_email_alert(s, LOG_NOTICE, "%s",
					 tmptrash->area);
			free_trash_chunk(tmptrash);
		}
	}
	else if (s->cur_eweight != s->next_eweight) {
		/* now propagate the status change to any LB algorithms */
		srv_lb_propagate(s);
	}
	return xferred;
}

/* deduct and update server state from an administrative change
 * (use current and next admin to deduct the administrative transition that
 *  may result in server state update)
 *
 * The function returns the number of requeued sessions (either taken by
 * the server or redispatched to others servers) due to the server state
 * change.
 */
static int _srv_update_status_adm(struct server *s, enum srv_adm_st_chg_cause cause)
{
	struct buffer *tmptrash = NULL;
	int srv_was_stopping = (s->cur_state == SRV_ST_STOPPING) || (s->cur_admin & SRV_ADMF_DRAIN);
	int xferred = 0;

	/* Maintenance must also disable health checks */
	if (!(s->cur_admin & SRV_ADMF_MAINT) && (s->next_admin & SRV_ADMF_MAINT)) {
		if (s->check.state & CHK_ST_ENABLED) {
			s->check.state |= CHK_ST_PAUSED;
			s->check.health = 0;
		}

		if (s->cur_state == SRV_ST_STOPPED) {	/* server was already down */
			tmptrash = alloc_trash_chunk();
			if (tmptrash) {
				chunk_printf(tmptrash,
				    "%sServer %s/%s was DOWN and now enters maintenance",
				    s->flags & SRV_F_BACKUP ? "Backup " : "", s->proxy->id, s->id);
				srv_append_adm_chg_cause(tmptrash, s, cause);
				srv_append_more(tmptrash, s, -1, (s->next_admin & SRV_ADMF_FMAINT));

				if (!(global.mode & MODE_STARTING)) {
					ha_warning("%s.\n", tmptrash->area);
					send_log(s->proxy, LOG_NOTICE, "%s.\n",
						 tmptrash->area);
				}
				free_trash_chunk(tmptrash);
			}
		}
		else {	/* server was still running */
			s->check.health = 0; /* failure */

			s->next_state = SRV_ST_STOPPED;
			srv_lb_propagate(s);

			if (s->onmarkeddown & HANA_ONMARKEDDOWN_SHUTDOWNSESSIONS)
				srv_shutdown_streams(s, SF_ERR_DOWN);

			/* force connection cleanup on the given server */
			srv_cleanup_connections(s);
			/* we might have streams queued on this server and waiting for
			 * a connection. Those which are redispatchable will be queued
			 * to another server or to the proxy itself.
			 */
			xferred = pendconn_redistribute(s);

			tmptrash = alloc_trash_chunk();
			if (tmptrash) {
				chunk_printf(tmptrash,
				             "%sServer %s/%s is going DOWN for maintenance",
				             s->flags & SRV_F_BACKUP ? "Backup " : "",
				             s->proxy->id, s->id);
				srv_append_adm_chg_cause(tmptrash, s, cause);
				srv_append_more(tmptrash, s, xferred, (s->next_admin & SRV_ADMF_FMAINT));

				if (!(global.mode & MODE_STARTING)) {
					ha_warning("%s.\n", tmptrash->area);
					send_log(s->proxy, srv_was_stopping ? LOG_NOTICE : LOG_ALERT, "%s.\n",
						 tmptrash->area);
				}
				free_trash_chunk(tmptrash);
			}
		}
	}
	else if ((s->cur_admin & SRV_ADMF_MAINT) && !(s->next_admin & SRV_ADMF_MAINT)) {
		/* OK here we're leaving maintenance, we have many things to check,
		 * because the server might possibly be coming back up depending on
		 * its state. In practice, leaving maintenance means that we should
		 * immediately turn to UP (more or less the slowstart) under the
		 * following conditions :
		 *   - server is neither checked nor tracked
		 *   - server tracks another server which is not checked
		 *   - server tracks another server which is already up
		 * Which sums up as something simpler :
		 * "either the tracking server is up or the server's checks are disabled
		 * or up". Otherwise we only re-enable health checks. There's a special
		 * case associated to the stopping state which can be inherited. Note
		 * that the server might still be in drain mode, which is naturally dealt
		 * with by the lower level functions.
		 */
		if (s->check.state & CHK_ST_ENABLED) {
			s->check.state &= ~CHK_ST_PAUSED;
			s->check.health = s->check.rise; /* start OK but check immediately */
		}

		if ((!s->track || s->track->next_state != SRV_ST_STOPPED) &&
		    (!(s->agent.state & CHK_ST_ENABLED) || (s->agent.health >= s->agent.rise)) &&
		    (!(s->check.state & CHK_ST_ENABLED) || (s->check.health >= s->check.rise))) {
			if (s->track && s->track->next_state == SRV_ST_STOPPING) {
				s->next_state = SRV_ST_STOPPING;
			}
			else {
				s->next_state = SRV_ST_STARTING;
				if (s->slowstart > 0) {
					if (s->warmup)
						task_schedule(s->warmup, tick_add(now_ms, MS_TO_TICKS(MAX(1000, s->slowstart / 20))));
				}
				else
					s->next_state = SRV_ST_RUNNING;
			}

		}

		tmptrash = alloc_trash_chunk();
		if (tmptrash) {
			if (!(s->next_admin & SRV_ADMF_FMAINT) && (s->cur_admin & SRV_ADMF_FMAINT)) {
				chunk_printf(tmptrash,
					     "%sServer %s/%s is %s/%s (leaving forced maintenance)",
					     s->flags & SRV_F_BACKUP ? "Backup " : "",
					     s->proxy->id, s->id,
					     (s->next_state == SRV_ST_STOPPED) ? "DOWN" : "UP",
					     (s->next_admin & SRV_ADMF_DRAIN) ? "DRAIN" : "READY");
			}
			if (!(s->next_admin & SRV_ADMF_RMAINT) && (s->cur_admin & SRV_ADMF_RMAINT)) {
				chunk_printf(tmptrash,
					     "%sServer %s/%s ('%s') is %s/%s (resolves again)",
					     s->flags & SRV_F_BACKUP ? "Backup " : "",
					     s->proxy->id, s->id, s->hostname,
					     (s->next_state == SRV_ST_STOPPED) ? "DOWN" : "UP",
					     (s->next_admin & SRV_ADMF_DRAIN) ? "DRAIN" : "READY");
			}
			if (!(s->next_admin & SRV_ADMF_IMAINT) && (s->cur_admin & SRV_ADMF_IMAINT)) {
				chunk_printf(tmptrash,
					     "%sServer %s/%s is %s/%s (leaving maintenance)",
					     s->flags & SRV_F_BACKUP ? "Backup " : "",
					     s->proxy->id, s->id,
					     (s->next_state == SRV_ST_STOPPED) ? "DOWN" : "UP",
					     (s->next_admin & SRV_ADMF_DRAIN) ? "DRAIN" : "READY");
			}
			ha_warning("%s.\n", tmptrash->area);
			send_log(s->proxy, LOG_NOTICE, "%s.\n",
				 tmptrash->area);
			free_trash_chunk(tmptrash);
		}

		server_recalc_eweight(s, 0);
		/* now propagate the status change to any LB algorithms */
		srv_lb_propagate(s);

		/* If the server is set with "on-marked-up shutdown-backup-sessions",
		 * and it's not a backup server and its effective weight is > 0,
		 * then it can accept new connections, so we shut down all streams
		 * on all backup servers.
		 */
		if ((s->onmarkedup & HANA_ONMARKEDUP_SHUTDOWNBACKUPSESSIONS) &&
		    !(s->flags & SRV_F_BACKUP) && s->next_eweight)
			srv_shutdown_backup_streams(s->proxy, SF_ERR_UP);

		/* check if we can handle some connections queued at the proxy. We
		 * will take as many as we can handle.
		 */
		xferred = pendconn_grab_from_px(s);
	}
	else if (s->next_admin & SRV_ADMF_MAINT) {
		/* remaining in maintenance mode, let's inform precisely about the
		 * situation.
		 */
		if (!(s->next_admin & SRV_ADMF_FMAINT) && (s->cur_admin & SRV_ADMF_FMAINT)) {
			tmptrash = alloc_trash_chunk();
			if (tmptrash) {
				chunk_printf(tmptrash,
				             "%sServer %s/%s is leaving forced maintenance but remains in maintenance",
				             s->flags & SRV_F_BACKUP ? "Backup " : "",
				             s->proxy->id, s->id);

				if (s->track) /* normally it's mandatory here */
					chunk_appendf(tmptrash, " via %s/%s",
				              s->track->proxy->id, s->track->id);
				ha_warning("%s.\n", tmptrash->area);
				send_log(s->proxy, LOG_NOTICE, "%s.\n",
					 tmptrash->area);
				free_trash_chunk(tmptrash);
			}
		}
		if (!(s->next_admin & SRV_ADMF_RMAINT) && (s->cur_admin & SRV_ADMF_RMAINT)) {
			tmptrash = alloc_trash_chunk();
			if (tmptrash) {
				chunk_printf(tmptrash,
				             "%sServer %s/%s ('%s') resolves again but remains in maintenance",
				             s->flags & SRV_F_BACKUP ? "Backup " : "",
				             s->proxy->id, s->id, s->hostname);

				if (s->track) /* normally it's mandatory here */
					chunk_appendf(tmptrash, " via %s/%s",
				              s->track->proxy->id, s->track->id);
				ha_warning("%s.\n", tmptrash->area);
				send_log(s->proxy, LOG_NOTICE, "%s.\n",
					 tmptrash->area);
				free_trash_chunk(tmptrash);
			}
		}
		else if (!(s->next_admin & SRV_ADMF_IMAINT) && (s->cur_admin & SRV_ADMF_IMAINT)) {
			tmptrash = alloc_trash_chunk();
			if (tmptrash) {
				chunk_printf(tmptrash,
				             "%sServer %s/%s remains in forced maintenance",
				             s->flags & SRV_F_BACKUP ? "Backup " : "",
				             s->proxy->id, s->id);
				ha_warning("%s.\n", tmptrash->area);
				send_log(s->proxy, LOG_NOTICE, "%s.\n",
					 tmptrash->area);
				free_trash_chunk(tmptrash);
			}
		}
		/* don't report anything when leaving drain mode and remaining in maintenance */
	}

	if (!(s->next_admin & SRV_ADMF_MAINT)) {
		if (!(s->cur_admin & SRV_ADMF_DRAIN) && (s->next_admin & SRV_ADMF_DRAIN)) {
			/* drain state is applied only if not yet in maint */

			srv_lb_propagate(s);

			/* we might have streams queued on this server and waiting for
			 * a connection. Those which are redispatchable will be queued
			 * to another server or to the proxy itself.
			 */
			xferred = pendconn_redistribute(s);

			tmptrash = alloc_trash_chunk();
			if (tmptrash) {
				chunk_printf(tmptrash, "%sServer %s/%s enters drain state",
					     s->flags & SRV_F_BACKUP ? "Backup " : "", s->proxy->id, s->id);
				srv_append_adm_chg_cause(tmptrash, s, cause);
				srv_append_more(tmptrash, s, xferred, (s->next_admin & SRV_ADMF_FDRAIN));

				if (!(global.mode & MODE_STARTING)) {
					ha_warning("%s.\n", tmptrash->area);
					send_log(s->proxy, LOG_NOTICE, "%s.\n",
						 tmptrash->area);
					send_email_alert(s, LOG_NOTICE, "%s",
							 tmptrash->area);
				}
				free_trash_chunk(tmptrash);
			}
		}
		else if ((s->cur_admin & SRV_ADMF_DRAIN) && !(s->next_admin & SRV_ADMF_DRAIN)) {
			/* OK completely leaving drain mode */
			server_recalc_eweight(s, 0);

			tmptrash = alloc_trash_chunk();
			if (tmptrash) {
				if (s->cur_admin & SRV_ADMF_FDRAIN) {
					chunk_printf(tmptrash,
						     "%sServer %s/%s is %s (leaving forced drain)",
						     s->flags & SRV_F_BACKUP ? "Backup " : "",
					             s->proxy->id, s->id,
					             (s->next_state == SRV_ST_STOPPED) ? "DOWN" : "UP");
				}
				else {
					chunk_printf(tmptrash,
					             "%sServer %s/%s is %s (leaving drain)",
					             s->flags & SRV_F_BACKUP ? "Backup " : "",
						     s->proxy->id, s->id,
						     (s->next_state == SRV_ST_STOPPED) ? "DOWN" : "UP");
					if (s->track) /* normally it's mandatory here */
						chunk_appendf(tmptrash, " via %s/%s",
					s->track->proxy->id, s->track->id);
				}

				ha_warning("%s.\n", tmptrash->area);
				send_log(s->proxy, LOG_NOTICE, "%s.\n",
					 tmptrash->area);
				free_trash_chunk(tmptrash);
			}

			/* now propagate the status change to any LB algorithms */
			srv_lb_propagate(s);
		}
		else if ((s->next_admin & SRV_ADMF_DRAIN)) {
			/* remaining in drain mode after removing one of its flags */

			tmptrash = alloc_trash_chunk();
			if (tmptrash) {
				if (!(s->next_admin & SRV_ADMF_FDRAIN)) {
					chunk_printf(tmptrash,
					             "%sServer %s/%s remains in drain mode",
					             s->flags & SRV_F_BACKUP ? "Backup " : "",
					             s->proxy->id, s->id);

					if (s->track) /* normally it's mandatory here */
						chunk_appendf(tmptrash, " via %s/%s",
					              s->track->proxy->id, s->track->id);
				}
				else {
					chunk_printf(tmptrash,
					             "%sServer %s/%s remains in forced drain mode",
					             s->flags & SRV_F_BACKUP ? "Backup " : "",
					             s->proxy->id, s->id);
				}
				ha_warning("%s.\n", tmptrash->area);
				send_log(s->proxy, LOG_NOTICE, "%s.\n",
					 tmptrash->area);
				free_trash_chunk(tmptrash);
			}
		}
	}
	return xferred;
}

/*
 * This function applies server's status changes.
 *
 * Must be called with the server lock held. This may also be called at init
 * time as the result of parsing the state file, in which case no lock will be
 * held, and the server's warmup task can be null.
 * <type> should be 0 for operational and 1 for administrative
 * <cause> must be srv_op_st_chg_cause enum for operational and
 * srv_adm_st_chg_cause enum for administrative
 */
static void srv_update_status(struct server *s, int type, int cause)
{
	int prev_srv_count = s->proxy->srv_bck + s->proxy->srv_act;
	enum srv_state srv_prev_state = s->cur_state;
	union {
		struct event_hdl_cb_data_server_state state;
		struct event_hdl_cb_data_server_admin admin;
		struct event_hdl_cb_data_server common;
	} cb_data;
	int requeued;

	/* prepare common server event data */
	_srv_event_hdl_prepare(&cb_data.common, s, 0);

	if (type) {
		cb_data.admin.safe.cause = cause;
		cb_data.admin.safe.old_admin = s->cur_admin;
		cb_data.admin.safe.new_admin = s->next_admin;
		requeued = _srv_update_status_adm(s, cause);
		cb_data.admin.safe.requeued = requeued;
		/* publish admin change */
		_srv_event_hdl_publish(EVENT_HDL_SUB_SERVER_ADMIN, cb_data.admin, s);
	}
	else
		requeued = _srv_update_status_op(s, cause);

	/* explicitly commit state changes (even if it was already applied implicitly
	 * by some lb state change function), so we don't miss anything
	 */
	srv_lb_commit_status(s);

	/* check if server stats must be updated due the the server state change */
	if (srv_prev_state != s->cur_state) {
		if (srv_prev_state == SRV_ST_STOPPED) {
			/* server was down and no longer is */
			if (s->counters.last_change < ns_to_sec(now_ns))                        // ignore negative times
				s->down_time += ns_to_sec(now_ns) - s->counters.last_change;
			_srv_event_hdl_publish(EVENT_HDL_SUB_SERVER_UP, cb_data.common, s);
		}
		else if (s->cur_state == SRV_ST_STOPPED) {
			/* server was up and is currently down */
			s->counters.down_trans++;
			_srv_event_hdl_publish(EVENT_HDL_SUB_SERVER_DOWN, cb_data.common, s);
		}
		s->counters.last_change = ns_to_sec(now_ns);

		/* publish the state change */
		_srv_event_hdl_prepare_state(&cb_data.state,
		                             s, type, cause, srv_prev_state, requeued);
		_srv_event_hdl_publish(EVENT_HDL_SUB_SERVER_STATE, cb_data.state, s);
	}

	/* check if backend stats must be updated due to the server state change */
	if (prev_srv_count && s->proxy->srv_bck == 0 && s->proxy->srv_act == 0)
		set_backend_down(s->proxy); /* backend going down */
	else if (!prev_srv_count && (s->proxy->srv_bck || s->proxy->srv_act)) {
		/* backend was down and is back up again:
		 * no helper function, updating last_change and backend downtime stats
		 */
		if (s->proxy->be_counters.last_change < ns_to_sec(now_ns))         // ignore negative times
			s->proxy->down_time += ns_to_sec(now_ns) - s->proxy->be_counters.last_change;
		s->proxy->be_counters.last_change = ns_to_sec(now_ns);
	}
}

struct task *srv_cleanup_toremove_conns(struct task *task, void *context, unsigned int state)
{
	struct connection *conn;

	while ((conn = MT_LIST_POP(&idle_conns[tid].toremove_conns,
	                               struct connection *, toremove_list)) != NULL) {
		conn->mux->destroy(conn->ctx);
	}

	return task;
}

/* Move <toremove_nb> count connections from <list> storage to <toremove_list>
 * list storage. -1 means moving all of them.
 *
 * Returns the number of connections moved.
 *
 * Must be called with idle_conns_lock held.
 */
static int srv_migrate_conns_to_remove(struct list *list, struct mt_list *toremove_list, int toremove_nb)
{
	struct connection *conn;
	int i = 0;

	while (!LIST_ISEMPTY(list)) {
		if (toremove_nb != -1 && i >= toremove_nb)
			break;

		conn = LIST_ELEM(list->n, struct connection *, idle_list);
		conn_delete_from_tree(conn);
		MT_LIST_APPEND(toremove_list, &conn->toremove_list);
		i++;
	}

	return i;
}
/* cleanup connections for a given server
 * might be useful when going on forced maintenance or live changing ip/port
 */
static void srv_cleanup_connections(struct server *srv)
{
	int did_remove;
	int i;

	/* nothing to do if pool-max-conn is null */
	if (!srv->max_idle_conns)
		return;

	/* check all threads starting with ours */
	for (i = tid;;) {
		did_remove = 0;
		HA_SPIN_LOCK(IDLE_CONNS_LOCK, &idle_conns[i].idle_conns_lock);
		if (srv_migrate_conns_to_remove(&srv->per_thr[i].idle_conn_list, &idle_conns[i].toremove_conns, -1) > 0)
			did_remove = 1;
		HA_SPIN_UNLOCK(IDLE_CONNS_LOCK, &idle_conns[i].idle_conns_lock);
		if (did_remove)
			task_wakeup(idle_conns[i].cleanup_task, TASK_WOKEN_OTHER);

		if ((i = ((i + 1 == global.nbthread) ? 0 : i + 1)) == tid)
			break;
	}
}

/* removes an idle conn after updating the server idle conns counters */
void srv_release_conn(struct server *srv, struct connection *conn)
{
	if (conn->flags & CO_FL_LIST_MASK) {
		/* The connection is currently in the server's idle list, so tell it
		 * there's one less connection available in that list.
		 */
		_HA_ATOMIC_DEC(&srv->curr_idle_conns);
		_HA_ATOMIC_DEC(conn->flags & CO_FL_SAFE_LIST ? &srv->curr_safe_nb : &srv->curr_idle_nb);
		_HA_ATOMIC_DEC(&srv->curr_idle_thr[tid]);
	}
	else {
		/* The connection is not private and not in any server's idle
		 * list, so decrement the current number of used connections
		 */
		_HA_ATOMIC_DEC(&srv->curr_used_conns);
	}

	/* Remove the connection from any tree (safe, idle or available) */
	if (conn->hash_node) {
		HA_SPIN_LOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
		conn_delete_from_tree(conn);
		conn->flags &= ~CO_FL_LIST_MASK;
		HA_SPIN_UNLOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
	}
}

/* retrieve a connection from its <hash> in <tree>
 * returns NULL if no connection found
 */
struct connection *srv_lookup_conn(struct eb_root *tree, uint64_t hash)
{
	struct eb64_node *node = NULL;
	struct connection *conn = NULL;
	struct conn_hash_node *hash_node = NULL;

	node = eb64_lookup(tree, hash);
	if (node) {
		hash_node = ebmb_entry(node, struct conn_hash_node, node);
		conn = hash_node->conn;
	}

	return conn;
}

/* retrieve the next connection sharing the same hash as <conn>
 * returns NULL if no connection found
 */
struct connection *srv_lookup_conn_next(struct connection *conn)
{
	struct eb64_node *node = NULL;
	struct connection *next_conn = NULL;
	struct conn_hash_node *hash_node = NULL;

	node = eb64_next_dup(&conn->hash_node->node);
	if (node) {
		hash_node = eb64_entry(node, struct conn_hash_node, node);
		next_conn = hash_node->conn;
	}

	return next_conn;
}

/* Add <conn> in <srv> idle trees. Set <is_safe> if connection is deemed safe
 * for reuse.
 *
 * This function is a simple wrapper for tree insert. It should only be used
 * for internal usage or when removing briefly the connection to avoid takeover
 * on it before reinserting it with this function. In other context, prefer to
 * use the full feature srv_add_to_idle_list().
 *
 * Must be called with idle_conns_lock.
 */
void _srv_add_idle(struct server *srv, struct connection *conn, int is_safe)
{
	struct eb_root *tree = is_safe ? &srv->per_thr[tid].safe_conns :
	                                 &srv->per_thr[tid].idle_conns;

	/* first insert in idle or safe tree. */
	eb64_insert(tree, &conn->hash_node->node);

	/* insert in list sorted by connection usage. */
	LIST_APPEND(&srv->per_thr[tid].idle_conn_list, &conn->idle_list);
}

/* This adds an idle connection to the server's list if the connection is
 * reusable, not held by any owner anymore, but still has available streams.
 */
int srv_add_to_idle_list(struct server *srv, struct connection *conn, int is_safe)
{
	/* we try to keep the connection in the server's idle list
	 * if we don't have too many FD in use, and if the number of
	 * idle+current conns is lower than what was observed before
	 * last purge, or if we already don't have idle conns for the
	 * current thread and we don't exceed last count by global.nbthread.
	 */
	if (!(conn->flags & CO_FL_PRIVATE) &&
	    srv && srv->pool_purge_delay > 0 &&
	    ((srv->proxy->options & PR_O_REUSE_MASK) != PR_O_REUSE_NEVR) &&
	    ha_used_fds < global.tune.pool_high_count &&
	    (srv->max_idle_conns == -1 || srv->max_idle_conns > srv->curr_idle_conns) &&
	    ((eb_is_empty(&srv->per_thr[tid].safe_conns) &&
	      (is_safe || eb_is_empty(&srv->per_thr[tid].idle_conns))) ||
	     (ha_used_fds < global.tune.pool_low_count &&
	      (srv->curr_used_conns + srv->curr_idle_conns <=
	       MAX(srv->curr_used_conns, srv->est_need_conns) + srv->low_idle_conns ||
	       (conn->flags & CO_FL_REVERSED)))) &&
	    !conn->mux->used_streams(conn) && conn->mux->avail_streams(conn)) {
		int retadd;

		retadd = _HA_ATOMIC_ADD_FETCH(&srv->curr_idle_conns, 1);
		if (retadd > srv->max_idle_conns) {
			_HA_ATOMIC_DEC(&srv->curr_idle_conns);
			return 0;
		}
		_HA_ATOMIC_DEC(&srv->curr_used_conns);

		HA_SPIN_LOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
		conn_delete_from_tree(conn);

		if (is_safe) {
			conn->flags = (conn->flags & ~CO_FL_LIST_MASK) | CO_FL_SAFE_LIST;
			_srv_add_idle(srv, conn, 1);
			_HA_ATOMIC_INC(&srv->curr_safe_nb);
		} else {
			conn->flags = (conn->flags & ~CO_FL_LIST_MASK) | CO_FL_IDLE_LIST;
			_srv_add_idle(srv, conn, 0);
			_HA_ATOMIC_INC(&srv->curr_idle_nb);
		}
		HA_SPIN_UNLOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
		_HA_ATOMIC_INC(&srv->curr_idle_thr[tid]);

		__ha_barrier_full();
		if ((volatile void *)srv->idle_node.node.leaf_p == NULL) {
			HA_SPIN_LOCK(OTHER_LOCK, &idle_conn_srv_lock);
			if ((volatile void *)srv->idle_node.node.leaf_p == NULL) {
				srv->idle_node.key = tick_add(srv->pool_purge_delay,
				                              now_ms);
				eb32_insert(&idle_conn_srv, &srv->idle_node);
				if (!task_in_wq(idle_conn_task) && !
				    task_in_rq(idle_conn_task)) {
					task_schedule(idle_conn_task,
					              srv->idle_node.key);
				}

			}
			HA_SPIN_UNLOCK(OTHER_LOCK, &idle_conn_srv_lock);
		}
		return 1;
	}
	return 0;
}

/* Insert <conn> connection in <srv> server available list. This is reserved
 * for backend connection currently in used with usable streams left.
 */
void srv_add_to_avail_list(struct server *srv, struct connection *conn)
{
	/* connection cannot be in idle list if used as an avail idle conn. */
	BUG_ON(LIST_INLIST(&conn->idle_list));
	eb64_insert(&srv->per_thr[tid].avail_conns, &conn->hash_node->node);
}

struct task *srv_cleanup_idle_conns(struct task *task, void *context, unsigned int state)
{
	struct server *srv;
	struct eb32_node *eb;
	int i;
	unsigned int next_wakeup;

	next_wakeup = TICK_ETERNITY;
	HA_SPIN_LOCK(OTHER_LOCK, &idle_conn_srv_lock);
	while (1) {
		int exceed_conns;
		int to_kill;
		int curr_idle;

		eb = eb32_lookup_ge(&idle_conn_srv, now_ms - TIMER_LOOK_BACK);
		if (!eb) {
			/* we might have reached the end of the tree, typically because
			 * <now_ms> is in the first half and we're first scanning the last
			* half. Let's loop back to the beginning of the tree now.
			*/

			eb = eb32_first(&idle_conn_srv);
			if (likely(!eb))
				break;
		}
		if (tick_is_lt(now_ms, eb->key)) {
			/* timer not expired yet, revisit it later */
			next_wakeup = eb->key;
			break;
		}
		srv = eb32_entry(eb, struct server, idle_node);

		/* Calculate how many idle connections we want to kill :
		 * we want to remove half the difference between the total
		 * of established connections (used or idle) and the max
		 * number of used connections.
		 */
		curr_idle = srv->curr_idle_conns;
		if (curr_idle == 0)
			goto remove;
		exceed_conns = srv->curr_used_conns + curr_idle - MAX(srv->max_used_conns, srv->est_need_conns);
		exceed_conns = to_kill = exceed_conns / 2 + (exceed_conns & 1);

		srv->est_need_conns = (srv->est_need_conns + srv->max_used_conns) / 2;
		if (srv->est_need_conns < srv->max_used_conns)
			srv->est_need_conns = srv->max_used_conns;

		HA_ATOMIC_STORE(&srv->max_used_conns, srv->curr_used_conns);

		if (exceed_conns <= 0)
			goto remove;

		/* check all threads starting with ours */
		for (i = tid;;) {
			int max_conn;
			int j;
			int did_remove = 0;

			max_conn = (exceed_conns * srv->curr_idle_thr[i]) /
			           curr_idle + 1;

			HA_SPIN_LOCK(IDLE_CONNS_LOCK, &idle_conns[i].idle_conns_lock);
			j = srv_migrate_conns_to_remove(&srv->per_thr[i].idle_conn_list, &idle_conns[i].toremove_conns, max_conn);
			if (j > 0)
				did_remove = 1;
			HA_SPIN_UNLOCK(IDLE_CONNS_LOCK, &idle_conns[i].idle_conns_lock);

			if (did_remove)
				task_wakeup(idle_conns[i].cleanup_task, TASK_WOKEN_OTHER);

			if ((i = ((i + 1 == global.nbthread) ? 0 : i + 1)) == tid)
				break;
		}
remove:
		eb32_delete(&srv->idle_node);

		if (srv->curr_idle_conns) {
			/* There are still more idle connections, add the
			 * server back in the tree.
			 */
			srv->idle_node.key = tick_add(srv->pool_purge_delay, now_ms);
			eb32_insert(&idle_conn_srv, &srv->idle_node);
			next_wakeup = tick_first(next_wakeup, srv->idle_node.key);
		}
	}
	HA_SPIN_UNLOCK(OTHER_LOCK, &idle_conn_srv_lock);

	task->expire = next_wakeup;
	return task;
}

/* Close remaining idle connections. This functions is designed to be run on
 * process shutdown. This guarantees a proper socket shutdown to avoid
 * TIME_WAIT state. For a quick operation, only ctrl is closed, xprt stack is
 * bypassed.
 *
 * This function is not thread-safe so it must only be called via a global
 * deinit function.
 */
static void srv_close_idle_conns(struct server *srv)
{
	struct eb_root **cleaned_tree;
	int i;

	for (i = 0; i < global.nbthread; ++i) {
		struct eb_root *conn_trees[] = {
			&srv->per_thr[i].idle_conns,
			&srv->per_thr[i].safe_conns,
			&srv->per_thr[i].avail_conns,
			NULL
		};

		for (cleaned_tree = conn_trees; *cleaned_tree; ++cleaned_tree) {
			while (!eb_is_empty(*cleaned_tree)) {
				struct ebmb_node *node = ebmb_first(*cleaned_tree);
				struct conn_hash_node *conn_hash_node = ebmb_entry(node, struct conn_hash_node, node);
				struct connection *conn = conn_hash_node->conn;

				if (conn->ctrl->ctrl_close)
					conn->ctrl->ctrl_close(conn);
				conn_delete_from_tree(conn);
			}
		}
	}
}

REGISTER_SERVER_DEINIT(srv_close_idle_conns);

/* config parser for global "tune.idle-pool.shared", accepts "on" or "off" */
static int cfg_parse_idle_pool_shared(char **args, int section_type, struct proxy *curpx,
                                      const struct proxy *defpx, const char *file, int line,
                                      char **err)
{
	if (too_many_args(1, args, err, NULL))
		return -1;

	if (strcmp(args[1], "on") == 0)
		global.tune.options |= GTUNE_IDLE_POOL_SHARED;
	else if (strcmp(args[1], "off") == 0)
		global.tune.options &= ~GTUNE_IDLE_POOL_SHARED;
	else {
		memprintf(err, "'%s' expects either 'on' or 'off' but got '%s'.", args[0], args[1]);
		return -1;
	}
	return 0;
}

/* config parser for global "tune.pool-{low,high}-fd-ratio" */
static int cfg_parse_pool_fd_ratio(char **args, int section_type, struct proxy *curpx,
                                   const struct proxy *defpx, const char *file, int line,
                                   char **err)
{
	int arg = -1;

	if (too_many_args(1, args, err, NULL))
		return -1;

	if (*(args[1]) != 0)
		arg = atoi(args[1]);

	if (arg < 0 || arg > 100) {
		memprintf(err, "'%s' expects an integer argument between 0 and 100.", args[0]);
		return -1;
	}

	if (args[0][10] == 'h')
		global.tune.pool_high_ratio = arg;
	else
		global.tune.pool_low_ratio = arg;
	return 0;
}

/* config keyword parsers */
static struct cfg_kw_list cfg_kws = {ILH, {
	{ CFG_GLOBAL, "tune.idle-pool.shared",       cfg_parse_idle_pool_shared },
	{ CFG_GLOBAL, "tune.pool-high-fd-ratio",     cfg_parse_pool_fd_ratio },
	{ CFG_GLOBAL, "tune.pool-low-fd-ratio",      cfg_parse_pool_fd_ratio },
	{ 0, NULL, NULL }
}};

INITCALL1(STG_REGISTER, cfg_register_keywords, &cfg_kws);

/*
 * Local variables:
 *  c-indent-level: 8
 *  c-basic-offset: 8
 * End:
 */