diff --git a/include/haproxy/dns-t.h b/include/haproxy/dns-t.h
index 2261570..1e68944 100644
--- a/include/haproxy/dns-t.h
+++ b/include/haproxy/dns-t.h
@@ -36,6 +36,9 @@
 /* DNS header size */
 #define DNS_HEADER_SIZE  ((int)sizeof(struct dns_header))
 
+/* max pending requests per stream */
+#define DNS_STREAM_MAX_PIPELINED_REQ	4
+
 #define DNS_TCP_MSG_MAX_SIZE 65535
 #define DNS_TCP_MSG_RING_MAX_SIZE (1 + 1 + 3 + DNS_TCP_MSG_MAX_SIZE) // varint_bytes(DNS_TCP_MSG_MAX_SIZE) == 3
 
@@ -70,12 +73,64 @@
  * extension set (client subnet, tcp keepalive, etc...)*/
 } __attribute__ ((packed));
 
+/* Structure describing a name server used during name resolution.
+ * A name server belongs to a resolvers section.
+ */
+struct dns_stream_server {
+	struct server *srv;
+	struct ring *ring_req;
+	int max_slots;
+	int maxconn;
+	int idle_conns;
+	int cur_conns;
+	int max_active_conns;
+	size_t ofs_req;           // ring buffer reader offset
+	size_t ofs_rsp;           // ring buffer reader offset
+	struct task *task_req;    /* req conn management */
+	struct task *task_rsp;    /* rsp management */
+	struct task *task_idle;   /* handle idle sess */
+	struct list free_sess;
+	struct list idle_sess;
+	struct list wait_sess;
+	__decl_thread(HA_SPINLOCK_T lock); // lock to protect current struct
+};
+
 struct dns_dgram_server {
 	struct dgram_conn conn;  /* transport layer */
 	struct ring *ring_req;
 	size_t ofs_req;           // ring buffer reader offset
 };
 
+struct dns_query {
+	struct eb32_node qid;
+	uint16_t original_qid;
+	int expire;
+	struct list list;
+};
+
+struct dns_session {
+	struct appctx *appctx; // appctx of current session
+	struct dns_stream_server *dss;
+	uint16_t tx_msg_offset;
+	int nb_queries;
+	int onfly_queries;
+	int query_counter;
+	struct list list;
+	struct list waiter;
+	struct list queries;
+	struct task *task_exp;
+	struct eb_root query_ids; /* tree to quickly lookup/retrieve query ids currently in use */
+	size_t ofs;            // ring buffer reader offset
+	struct ring ring;
+	struct  {
+		uint16_t len;
+		uint16_t offset;
+		char *area;
+	} rx_msg;
+	unsigned char *tx_ring_area;
+	int shutdown;
+};
+
 /* Structure describing a name server
  */
 struct dns_nameserver {
@@ -88,6 +143,7 @@
 
 	int (*process_responses)(struct dns_nameserver *ns); /* callback used to process responses */
 	struct dns_dgram_server *dgram;  /* used for dgram dns */
+	struct dns_stream_server *stream; /* used for tcp dns */
 
 	EXTRA_COUNTERS(extra_counters);
 	struct dns_counters *counters;
diff --git a/include/haproxy/dns.h b/include/haproxy/dns.h
index dd3477d..00bfee0 100644
--- a/include/haproxy/dns.h
+++ b/include/haproxy/dns.h
@@ -23,9 +23,11 @@
 #define _HAPROXY_DNS_H
 
 #include <haproxy/dns-t.h>
+#include <haproxy/server-t.h>
 
 int dns_send_nameserver(struct dns_nameserver *ns, void *buf, size_t len);
 ssize_t dns_recv_nameserver(struct dns_nameserver *ns, void *data, size_t size);
 int dns_dgram_init(struct dns_nameserver *ns, struct sockaddr_storage *sk);
+int dns_stream_init(struct dns_nameserver *ns, struct server *s);
 
 #endif // _HAPROXY_DNS_H
diff --git a/src/dns.c b/src/dns.c
index 5fc656f..352e88c 100644
--- a/src/dns.c
+++ b/src/dns.c
@@ -31,9 +31,15 @@
 #include <haproxy/fd.h>
 #include <haproxy/log.h>
 #include <haproxy/ring.h>
+#include <haproxy/stream.h>
+#include <haproxy/stream_interface.h>
 
 static THREAD_LOCAL char *dns_msg_trash;
 
+DECLARE_STATIC_POOL(dns_session_pool, "dns_session", sizeof(struct dns_session));
+DECLARE_STATIC_POOL(dns_query_pool, "dns_query", sizeof(struct dns_query));
+DECLARE_STATIC_POOL(dns_msg_buf, "dns_msg_buf", DNS_TCP_MSG_RING_MAX_SIZE);
+
 /* Opens an UDP socket on the namesaver's IP/Port, if required. Returns 0 on
  * success, -1 otherwise.
  */
@@ -115,10 +121,25 @@
 		}
 		ns->counters->sent++;
 	}
+	else if (ns->stream) {
+		struct ist myist;
+
+		myist.ptr = buf;
+		myist.len = len;
+                ret = ring_write(ns->stream->ring_req, DNS_TCP_MSG_MAX_SIZE, NULL, 0, &myist, 1);
+		if (!ret) {
+			ns->counters->snd_error++;
+			return -1;
+		}
+		task_wakeup(ns->stream->task_req, TASK_WOKEN_MSG);
+		return ret;
+	}
 
 	return ret;
 }
 
+void dns_session_free(struct dns_session *);
+
 /* Receives a dns message
  * Returns message length
  * 0 is returned if no more message available
@@ -146,6 +167,79 @@
 			return -1;
 		}
 	}
+	else if (ns->stream) {
+		struct dns_stream_server *dss = ns->stream;
+		struct dns_session *ds;
+
+		HA_SPIN_LOCK(DNS_LOCK, &dss->lock);
+
+		if (!LIST_ISEMPTY(&dss->wait_sess)) {
+			ds = LIST_NEXT(&dss->wait_sess, struct dns_session *, waiter);
+			fprintf(stderr, "ds: %p\n", ds);
+			ret = ds->rx_msg.len < size ? ds->rx_msg.len : size;
+			memcpy(data, ds->rx_msg.area, ret);
+
+			ds->rx_msg.len = 0;
+
+			/* This barrier is here to ensure that all data is
+			 * stored if the appctx detect the elem is out of the list */
+			__ha_barrier_store();
+
+			LIST_DEL_INIT(&ds->waiter);
+
+			if (ds->appctx) {
+				/* This second barrier is here to ensure that
+				 * the waked up appctx won't miss that the
+				 * elem is removed from the list */
+				__ha_barrier_store();
+
+				/* awake appctx beacause it may have other
+				 * message to receive
+				 */
+				appctx_wakeup(ds->appctx);
+
+				/* dns_session could already be into free_sess list
+				 * so we firstly remove it */
+				LIST_DEL_INIT(&ds->list);
+
+				/* decrease nb_queries to free a slot for a new query on that sess */
+				ds->nb_queries--;
+				if (ds->nb_queries) {
+					/* it remains pipelined unanswered request
+					 * into this session but we just decrease
+					 * the counter so the session
+					 * can not be full of pipelined requests
+					 * so we can add if to free_sess list
+					 * to receive a new request
+					*/
+					LIST_ADD(&ds->dss->free_sess, &ds->list);
+				}
+				else {
+					/* there is no more pipelined requests
+					 * into this session, so we move it
+					 * to idle_sess list */
+					LIST_ADD(&ds->dss->idle_sess, &ds->list);
+
+					/* update the counter of idle sessions */
+					ds->dss->idle_conns++;
+
+					/* Note: this is useless there to update
+					 * the max_active_conns since we increase
+					 * the idle count */
+				}
+			}
+			else {
+				/* there is no more appctx for this session
+				 * it means it is ready to die
+				 */
+				dns_session_free(ds);
+			}
+
+
+		}
+
+		HA_SPIN_UNLOCK(DNS_LOCK, &dss->lock);
+	}
 
 	return ret;
 }
@@ -309,6 +403,873 @@
 
 	free(dgram);
 
+	return -1;
+}
+
+/*
+ * IO Handler to handle message push to dns tcp server
+ */
+static void dns_session_io_handler(struct appctx *appctx)
+{
+	struct stream_interface *si = appctx->owner;
+	struct dns_session *ds = appctx->ctx.sft.ptr;
+	struct ring *ring = &ds->ring;
+	struct buffer *buf = &ring->buf;
+	uint64_t msg_len;
+	int available_room;
+	size_t len, cnt, ofs;
+	int ret = 0;
+
+	/* if stopping was requested, close immediately */
+	if (unlikely(stopping))
+		goto close;
+
+	/* we want to be sure to not miss that we have been awaked for a shutdown */
+	__ha_barrier_load();
+
+	/* that means the connection was requested to shutdown
+	 * for instance idle expire */
+	if (ds->shutdown)
+		goto close;
+
+	/* an error was detected */
+	if (unlikely(si_ic(si)->flags & (CF_WRITE_ERROR|CF_SHUTW)))
+		goto close;
+
+	/* con closed by server side, we will skip data write and drain data from channel */
+	if ((si_oc(si)->flags & CF_SHUTW)) {
+		goto read;
+	}
+
+	/* if the connection is not established, inform the stream that we want
+	 * to be notified whenever the connection completes.
+	 */
+	if (si_opposite(si)->state < SI_ST_EST) {
+		si_cant_get(si);
+		si_rx_conn_blk(si);
+		si_rx_endp_more(si);
+		return;
+	}
+
+
+	ofs = ds->ofs;
+
+	HA_RWLOCK_WRLOCK(DNS_LOCK, &ring->lock);
+	LIST_DEL_INIT(&appctx->wait_entry);
+	HA_RWLOCK_WRUNLOCK(DNS_LOCK, &ring->lock);
+
+	HA_RWLOCK_RDLOCK(DNS_LOCK, &ring->lock);
+
+	/* explanation for the initialization below: it would be better to do
+	 * this in the parsing function but this would occasionally result in
+	 * dropped events because we'd take a reference on the oldest message
+	 * and keep it while being scheduled. Thus instead let's take it the
+	 * first time we enter here so that we have a chance to pass many
+	 * existing messages before grabbing a reference to a location. This
+	 * value cannot be produced after initialization.
+	 */
+	if (unlikely(ofs == ~0)) {
+		ofs = 0;
+
+		HA_ATOMIC_ADD(b_peek(buf, ofs), 1);
+		ofs += ring->ofs;
+	}
+
+	/* in this loop, ofs always points to the counter byte that precedes
+	 * the message so that we can take our reference there if we have to
+	 * stop before the end (ret=0).
+	 */
+	if (si_opposite(si)->state == SI_ST_EST) {
+		/* we were already there, adjust the offset to be relative to
+		 * the buffer's head and remove us from the counter.
+		 */
+		ofs -= ring->ofs;
+		BUG_ON(ofs >= buf->size);
+		HA_ATOMIC_SUB(b_peek(buf, ofs), 1);
+
+		ret = 1;
+		while (ofs + 1 < b_data(buf)) {
+			struct dns_query *query;
+			uint16_t original_qid;
+			uint16_t new_qid;
+
+			cnt = 1;
+			len = b_peek_varint(buf, ofs + cnt, &msg_len);
+			if (!len)
+				break;
+			cnt += len;
+			BUG_ON(msg_len + ofs + cnt + 1 > b_data(buf));
+
+			/* retrieve available room on output channel */
+			available_room = channel_recv_max(si_ic(si));
+
+			/* tx_msg_offset null means we are at the start of a new message */
+			if (!ds->tx_msg_offset) {
+				uint16_t slen;
+
+				/* check if there is enough room to put message len and query id */
+				if (available_room < sizeof(slen) + sizeof(new_qid)) {
+					si_rx_room_blk(si);
+					ret = 0;
+					break;
+				}
+
+				/* put msg len into then channel */
+				slen = (uint16_t)msg_len;
+				slen = htons(slen);
+				ci_putblk(si_ic(si), (char *)&slen, sizeof(slen));
+				available_room -= sizeof(slen);
+
+				/* backup original query id */
+				len = b_getblk(buf, (char *)&original_qid, sizeof(original_qid), ofs + cnt);
+
+				/* generates new query id */
+				new_qid = ++ds->query_counter;
+				new_qid = htons(new_qid);
+
+				/* put new query id into the channel */
+				ci_putblk(si_ic(si), (char *)&new_qid, sizeof(new_qid));
+				available_room -= sizeof(new_qid);
+
+				/* keep query id mapping */
+
+				query = pool_alloc(dns_query_pool);
+				if (query) {
+					query->qid.key = new_qid;
+					query->original_qid = original_qid;
+					query->expire = tick_add(now_ms, 5000);
+					LIST_INIT(&query->list);
+					if (LIST_ISEMPTY(&ds->queries)) {
+						/* enable task to handle expire */
+						ds->task_exp->expire = query->expire;
+						/* ensure this will be executed by the same
+						 * thread than ds_session_release
+						 * to ensure session_release is free
+						 * to destroy the task */
+						task_queue(ds->task_exp);
+					}
+					LIST_ADDQ(&ds->queries, &query->list);
+					eb32_insert(&ds->query_ids, &query->qid);
+					ds->onfly_queries++;
+				}
+
+				/* update the tx_offset to handle output in 16k streams */
+				ds->tx_msg_offset = sizeof(original_qid);
+
+			}
+
+			/* check if it remains available room on output chan */
+			if (unlikely(!available_room)) {
+				si_rx_room_blk(si);
+				ret = 0;
+				break;
+			}
+
+			chunk_reset(&trash);
+			if ((msg_len - ds->tx_msg_offset) > available_room) {
+				/* remaining msg data is too large to be written in output channel at one time */
+
+				len = b_getblk(buf, trash.area, available_room, ofs + cnt + ds->tx_msg_offset);
+
+				/* update offset to complete mesg forwarding later */
+				ds->tx_msg_offset += len;
+			}
+			else {
+				/* remaining msg data can be written in output channel at one time */
+				len = b_getblk(buf, trash.area, msg_len - ds->tx_msg_offset, ofs + cnt + ds->tx_msg_offset);
+
+				/* reset tx_msg_offset to mark forward fully processed */
+				ds->tx_msg_offset = 0;
+			}
+			trash.data += len;
+
+			ci_putchk(si_ic(si), &trash);
+
+			if (ds->tx_msg_offset) {
+				/* msg was not fully processed, we must  be awake to drain pending data */
+
+				si_rx_room_blk(si);
+				ret = 0;
+				break;
+			}
+			/* switch to next message */
+			ofs += cnt + msg_len;
+		}
+
+		HA_ATOMIC_ADD(b_peek(buf, ofs), 1);
+		ofs += ring->ofs;
+		ds->ofs = ofs;
+	}
+	HA_RWLOCK_RDUNLOCK(DNS_LOCK, &ring->lock);
+
+	if (ret) {
+		/* let's be woken up once new request to write arrived */
+		HA_RWLOCK_WRLOCK(DNS_LOCK, &ring->lock);
+		LIST_ADDQ(&ring->waiters, &appctx->wait_entry);
+		HA_RWLOCK_WRUNLOCK(DNS_LOCK, &ring->lock);
+		si_rx_endp_done(si);
+	}
+
+read:
+
+	/* if session is not a waiter it means there is no commited
+	 * message into rx_buf and we are free to use it
+	 * Note: we need a load barrier here to not miss the
+	 * delete from the list
+	 */
+	__ha_barrier_load();
+	if (!LIST_ADDED(&ds->waiter)) {
+		while (1) {
+			uint16_t query_id;
+			struct eb32_node *eb;
+			struct dns_query *query;
+
+			if (!ds->rx_msg.len) {
+				/* next message len is not fully available into the channel */
+				if (co_data(si_oc(si)) < 2)
+					break;
+
+				/* retrieve message len */
+				co_getblk(si_oc(si), (char *)&msg_len, 2, 0);
+
+				/* mark as consumed */
+				co_skip(si_oc(si), 2);
+
+				/* store message len */
+				ds->rx_msg.len = ntohs(msg_len);
+			}
+
+			if (!co_data(si_oc(si))) {
+				/* we need more data but nothing is available */
+				break;
+			}
+
+			if (co_data(si_oc(si)) + ds->rx_msg.offset < ds->rx_msg.len) {
+				/* message only partially available */
+
+				/* read available data */
+				co_getblk(si_oc(si), ds->rx_msg.area + ds->rx_msg.offset, co_data(si_oc(si)), 0);
+
+				/* update message offset */
+				ds->rx_msg.offset += co_data(si_oc(si));
+
+				/* consume all pending data from the channel */
+				co_skip(si_oc(si), co_data(si_oc(si)));
+
+				/* we need to wait for more data */
+				break;
+			}
+
+			/* enougth data is available into the channel to read the message until the end */
+
+			/* read from the channel until the end of the message */
+			co_getblk(si_oc(si), ds->rx_msg.area + ds->rx_msg.offset, ds->rx_msg.len - ds->rx_msg.offset, 0);
+
+			/* consume all data until the end of the message from the channel */
+			co_skip(si_oc(si), ds->rx_msg.len - ds->rx_msg.offset);
+
+			/* reset reader offset to 0 for next message reand */
+			ds->rx_msg.offset = 0;
+
+			/* try remap query id to original */
+			memcpy(&query_id, ds->rx_msg.area, sizeof(query_id));
+			eb = eb32_lookup(&ds->query_ids, query_id);
+			if (!eb) {
+				/* query id not found means we have an unknown corresponding
+				 * request, perhaps server's bug or or the query reached
+				 * timeout
+				*/
+				ds->rx_msg.len = 0;
+				continue;
+			}
+
+			/* re-map the original query id set by the requester */
+			query = eb32_entry(eb, struct dns_query, qid);
+			memcpy(ds->rx_msg.area, &query->original_qid, sizeof(query->original_qid));
+
+			/* remove query ids mapping from pending queries list/tree */
+			eb32_delete(&query->qid);
+			LIST_DEL(&query->list);
+			pool_free(dns_query_pool, query);
+			ds->onfly_queries--;
+
+			/* lock the dns_stream_server containing lists heads */
+			HA_SPIN_LOCK(DNS_LOCK, &ds->dss->lock);
+
+			/* the dns_session is also added in queue of the
+			 * wait_sess list where the task processing
+			 * response will pop available responses
+			 */
+			LIST_ADDQ(&ds->dss->wait_sess, &ds->waiter);
+
+			/* lock the dns_stream_server containing lists heads */
+			HA_SPIN_UNLOCK(DNS_LOCK, &ds->dss->lock);
+
+			/* awake the task processing the responses */
+			task_wakeup(ds->dss->task_rsp, TASK_WOKEN_INIT);
+
+			break;
+		}
+
+		if (!LIST_ADDED(&ds->waiter)) {
+			/* there is no more pending data to read and the con was closed by the server side */
+			if (!co_data(si_oc(si)) && (si_oc(si)->flags & CF_SHUTW)) {
+				goto close;
+			}
+		}
+
+	}
+
+
+	return;
+close:
+	si_shutw(si);
+	si_shutr(si);
+	si_ic(si)->flags |= CF_READ_NULL;
+}
+
+void dns_queries_flush(struct dns_session *ds)
+{
+	struct dns_query *query, *queryb;
+
+	list_for_each_entry_safe(query, queryb, &ds->queries, list) {
+		eb32_delete(&query->qid);
+		LIST_DEL(&query->list);
+		pool_free(dns_query_pool, query);
+	}
+}
+
+void dns_session_free(struct dns_session *ds)
+{
+	if (ds->rx_msg.area)
+		pool_free(dns_msg_buf, ds->rx_msg.area);
+	if (ds->tx_ring_area)
+		pool_free(dns_msg_buf, ds->tx_ring_area);
+	if (ds->task_exp)
+		task_destroy(ds->task_exp);
+
+	dns_queries_flush(ds);
+
+	ds->dss->cur_conns--;
+	/* Note: this is useless to update
+	 * max_active_conns here because
+	 * we decrease the value
+	 */
+	pool_free(dns_session_pool, ds);
+}
+
+static struct appctx *dns_session_create(struct dns_session *ds);
+
+/*
+ * Function to release a DNS tcp session
+ */
+static void dns_session_release(struct appctx *appctx)
+{
+	struct dns_session *ds = appctx->ctx.sft.ptr;
+	struct dns_stream_server *dss;
+
+	if (!ds)
+		return;
+
+	dss = ds->dss;
+
+	HA_SPIN_LOCK(DNS_LOCK, &dss->lock);
+	LIST_DEL_INIT(&ds->list);
+
+	if (stopping) {
+		dns_session_free(ds);
+		HA_SPIN_UNLOCK(DNS_LOCK, &dss->lock);
+		return;
+	}
+
+	if (!ds->nb_queries) {
+		/* this is an idle session */
+		/* Note: this is useless to update max_active_sess
+		 * here because we decrease idle_conns but
+		 * dns_session_free decrease curconns
+		 */
+
+		ds->dss->idle_conns--;
+		dns_session_free(ds);
+		HA_SPIN_UNLOCK(DNS_LOCK, &dss->lock);
+		return;
+	}
+
+	if (ds->onfly_queries == ds->nb_queries) {
+		/* the session can be released because
+		 * it means that all queries AND
+		 * responses are in fly */
+		dns_session_free(ds);
+		HA_SPIN_UNLOCK(DNS_LOCK, &dss->lock);
+		return;
+	}
+
+	/* We do not call ring_appctx_detach here
+	 * because we want to keep readers counters
+	 * to retry a con with a different appctx*/
+	HA_RWLOCK_WRLOCK(DNS_LOCK, &ds->ring.lock);
+	LIST_DEL_INIT(&appctx->wait_entry);
+	HA_RWLOCK_WRUNLOCK(DNS_LOCK, &ds->ring.lock);
+
+	/* if there is no pending complete response
+	 * message, ensure to reset
+	 * message offsets if the session
+	 * was closed with an incomplete pending response
+	 */
+	if (!LIST_ADDED(&ds->waiter))
+		ds->rx_msg.len = ds->rx_msg.offset = 0;
+
+	/* we flush pending sent queries because we never
+	 * have responses
+	 */
+	ds->nb_queries -= ds->onfly_queries;
+	dns_queries_flush(ds);
+
+	/* reset offset to be sure to start from message start */
+	ds->tx_msg_offset = 0;
+
+	/* here the ofs and the attached counter
+	 * are kept unchanged
+	 */
+
+	/* Create a new appctx, We hope we can
+	 * create from the release callback! */
+	ds->appctx = dns_session_create(ds);
+	if (!ds->appctx) {
+		dns_session_free(ds);
+		HA_SPIN_UNLOCK(DNS_LOCK, &dss->lock);
+		return;
+	}
+
+	if (ds->nb_queries < DNS_STREAM_MAX_PIPELINED_REQ)
+		LIST_ADD(&ds->dss->free_sess, &ds->list);
+
+	HA_SPIN_UNLOCK(DNS_LOCK, &dss->lock);
+}
+
+/* DNS tcp session applet */
+static struct applet dns_session_applet = {
+	.obj_type = OBJ_TYPE_APPLET,
+	.name = "<STRMDNS>", /* used for logging */
+	.fct = dns_session_io_handler,
+	.release = dns_session_release,
+};
+
+/*
+ * Function used to create an appctx for a DNS session
+ */
+static struct appctx *dns_session_create(struct dns_session *ds)
+{
+	struct appctx *appctx;
+	struct session *sess;
+	struct stream *s;
+	struct applet *applet = &dns_session_applet;
+
+	appctx = appctx_new(applet, tid_bit);
+	if (!appctx)
+		goto out_close;
+
+	appctx->ctx.sft.ptr = (void *)ds;
+
+	sess = session_new(ds->dss->srv->proxy, NULL, &appctx->obj_type);
+	if (!sess) {
+		ha_alert("out of memory in peer_session_create().\n");
+		goto out_free_appctx;
+	}
+
+	if ((s = stream_new(sess, &appctx->obj_type, &BUF_NULL)) == NULL) {
+		ha_alert("Failed to initialize stream in peer_session_create().\n");
+		goto out_free_sess;
+	}
+
+
+	s->target = &ds->dss->srv->obj_type;
+	if (!sockaddr_alloc(&s->target_addr, &ds->dss->srv->addr, sizeof(ds->dss->srv->addr)))
+		goto out_free_strm;
+	s->flags = SF_ASSIGNED|SF_ADDR_SET;
+	s->si[1].flags |= SI_FL_NOLINGER;
+
+	s->do_log = NULL;
+	s->uniq_id = 0;
+
+	s->res.flags |= CF_READ_DONTWAIT;
+	/* for rto and rex to eternity to not expire on idle recv:
+	 * We are using a syslog server.
+	 */
+	s->res.rto = TICK_ETERNITY;
+	s->res.rex = TICK_ETERNITY;
+	ds->appctx = appctx;
+	task_wakeup(s->task, TASK_WOKEN_INIT);
+	return appctx;
+
+	/* Error unrolling */
+ out_free_strm:
+	LIST_DEL(&s->list);
+	pool_free(pool_head_stream, s);
+ out_free_sess:
+	session_free(sess);
+ out_free_appctx:
+	appctx_free(appctx);
+ out_close:
+	return NULL;
+}
+
+/* Task processing expiration of unresponded queries, this one is supposed
+ * to be stuck on the same thread than the appctx handler
+ */
+static struct task *dns_process_query_exp(struct task *t, void *context, unsigned short state)
+{
+	struct dns_session *ds = (struct dns_session *)context;
+	struct dns_query *query, *queryb;
+
+	t->expire = TICK_ETERNITY;
+
+	list_for_each_entry_safe(query, queryb, &ds->queries, list) {
+		if (tick_is_expired(query->expire, now_ms)) {
+			eb32_delete(&query->qid);
+			LIST_DEL(&query->list);
+			pool_free(dns_query_pool, query);
+			ds->onfly_queries--;
+		}
+		else {
+			t->expire = query->expire;
+			break;
+		}
+	}
+
+	return t;
+}
+
+/* Task processing expiration of idle sessions */
+static struct task *dns_process_idle_exp(struct task *t, void *context, unsigned short state)
+{
+	struct dns_stream_server *dss = (struct dns_stream_server *)context;
+	struct dns_session *ds, *dsb;
+	int target = 0;
+	int cur_active_conns;
+
+	HA_SPIN_LOCK(DNS_LOCK, &dss->lock);
+
+
+	cur_active_conns = dss->cur_conns - dss->idle_conns;
+	if (cur_active_conns > dss->max_active_conns)
+		dss->max_active_conns = cur_active_conns;
+
+	target = (dss->max_active_conns - cur_active_conns) / 2;
+	list_for_each_entry_safe(ds, dsb, &dss->idle_sess, list) {
+		if (!target)
+			break;
+
+		/* remove conn to pending list to ensure it won't be reused */
+		LIST_DEL_INIT(&ds->list);
+
+		/* force session shutdown */
+		ds->shutdown = 1;
+
+		/* to be sure that the appctx wont miss shutdown */
+		__ha_barrier_store();
+
+		/* wake appctx to perform the shutdown */
+		appctx_wakeup(ds->appctx);
+	}
+
+	/* reset max to current active conns */
+	dss->max_active_conns = cur_active_conns;
+
+	HA_SPIN_UNLOCK(DNS_LOCK, &dss->lock);
+
+	t->expire = tick_add(now_ms, 5000);
+
+	return t;
+}
+
+struct dns_session *dns_session_new(struct dns_stream_server *dss)
+{
+	struct dns_session *ds;
+
+	if (dss->maxconn && (dss->maxconn <= dss->cur_conns))
+		return NULL;
+
+	ds = pool_alloc(dns_session_pool);
+	if (!ds)
+		return NULL;
+
+	ds->ofs = ~0;
+	ds->dss = dss;
+	LIST_INIT(&ds->list);
+	LIST_INIT(&ds->queries);
+	LIST_INIT(&ds->waiter);
+	ds->rx_msg.offset = ds->rx_msg.len = 0;
+	ds->rx_msg.area = NULL;
+	ds->tx_ring_area = NULL;
+	ds->task_exp = NULL;
+	ds->appctx = NULL;
+	ds->shutdown = 0;
+	ds->nb_queries = 0;
+	ds->query_ids = EB_ROOT_UNIQUE;
+	ds->rx_msg.area = pool_alloc(dns_msg_buf);
+	if (!ds->rx_msg.area)
+		goto error;
+
+	ds->tx_ring_area = pool_alloc(dns_msg_buf);
+	if (!ds->tx_ring_area)
+		goto error;
+
+	ring_init(&ds->ring, ds->tx_ring_area, DNS_TCP_MSG_RING_MAX_SIZE);
+	ring_attach(&ds->ring);
+
+	if ((ds->task_exp = task_new(tid_bit)) == NULL)
+		goto error;
+
+	ds->task_exp->process = dns_process_query_exp;
+	ds->task_exp->context = ds;
+
+	ds->appctx = dns_session_create(ds);
+	if (!ds->appctx)
+		goto error;
+
+	dss->cur_conns++;
+
+	return ds;
+
+error:
+	if (ds->task_exp)
+		task_destroy(ds->task_exp);
+	if (ds->rx_msg.area)
+		pool_free(dns_msg_buf, ds->rx_msg.area);
+	if (ds->tx_ring_area)
+		pool_free(dns_msg_buf, ds->tx_ring_area);
+
+	pool_free(dns_session_pool, ds);
+
+	return NULL;
+}
+
+/*
+ * Task used to consume pending messages from nameserver ring
+ * and forward them to dns_session ring.
+ * Note: If no slot found a new dns_session is allocated
+ */
+static struct task *dns_process_req(struct task *t, void *context, unsigned short state)
+{
+	struct dns_nameserver *ns = (struct dns_nameserver *)context;
+	struct dns_stream_server *dss = ns->stream;
+	struct ring *ring = dss->ring_req;
+	struct buffer *buf = &ring->buf;
+	uint64_t msg_len;
+	size_t len, cnt, ofs;
+	struct dns_session *ds, *ads;
+	HA_SPIN_LOCK(DNS_LOCK, &dss->lock);
+
+	ofs = dss->ofs_req;
+
+	HA_RWLOCK_RDLOCK(DNS_LOCK, &ring->lock);
+
+	/* explanation for the initialization below: it would be better to do
+	 * this in the parsing function but this would occasionally result in
+	 * dropped events because we'd take a reference on the oldest message
+	 * and keep it while being scheduled. Thus instead let's take it the
+	 * first time we enter here so that we have a chance to pass many
+	 * existing messages before grabbing a reference to a location. This
+	 * value cannot be produced after initialization.
+	 */
+	if (unlikely(ofs == ~0)) {
+		ofs = 0;
+		HA_ATOMIC_ADD(b_peek(buf, ofs), 1);
+		ofs += ring->ofs;
+	}
+
+	/* we were already there, adjust the offset to be relative to
+	 * the buffer's head and remove us from the counter.
+	 */
+	ofs -= ring->ofs;
+	BUG_ON(ofs >= buf->size);
+	HA_ATOMIC_SUB(b_peek(buf, ofs), 1);
+
+	while (ofs + 1 < b_data(buf)) {
+		struct ist myist;
+
+		cnt = 1;
+		len = b_peek_varint(buf, ofs + cnt, &msg_len);
+		if (!len)
+			break;
+		cnt += len;
+		BUG_ON(msg_len + ofs + cnt + 1 > b_data(buf));
+		if (unlikely(msg_len > DNS_TCP_MSG_MAX_SIZE)) {
+			/* too large a message to ever fit, let's skip it */
+			ofs += cnt + msg_len;
+			continue;
+		}
+
+		len = b_getblk(buf, dns_msg_trash, msg_len, ofs + cnt);
+
+		myist.ptr = dns_msg_trash;
+		myist.len = len;
+
+		ads = NULL;
+		/* try to push request into activ sess with free slot */
+		if (!LIST_ISEMPTY(&dss->free_sess)) {
+			ds = LIST_NEXT(&dss->free_sess, struct dns_session *, list);
+
+			if (ring_write(&ds->ring, DNS_TCP_MSG_MAX_SIZE, NULL, 0, &myist, 1) > 0) {
+				ds->nb_queries++;
+				if (ds->nb_queries >= DNS_STREAM_MAX_PIPELINED_REQ)
+					LIST_DEL_INIT(&ds->list);
+				ads = ds;
+			}
+			else {
+				/* it means we were unable to put a request in this slot,
+				 * it may be close to be full so we put it at the end
+				 * of free conn list */
+				LIST_DEL_INIT(&ds->list);
+				LIST_ADDQ(&dss->free_sess, &ds->list);
+			}
+		}
+
+		if (!ads) {
+			/* try to push request into idle, this one should have enought free space */
+			if (!LIST_ISEMPTY(&dss->idle_sess)) {
+				ds = LIST_NEXT(&dss->idle_sess, struct dns_session *, list);
+
+				/* ring is empty so this ring_write should never fail */
+				ring_write(&ds->ring, DNS_TCP_MSG_MAX_SIZE, NULL, 0, &myist, 1);
+				ds->nb_queries++;
+				LIST_DEL_INIT(&ds->list);
+
+				ds->dss->idle_conns--;
+
+				/* we may have to update the max_active_conns */
+				if (ds->dss->max_active_conns < ds->dss->cur_conns - ds->dss->idle_conns)
+					ds->dss->max_active_conns = ds->dss->cur_conns - ds->dss->idle_conns;
+
+				/* since we may unable to find a free list to handle
+				 * this request, this request may be large and fill
+				 * the ring buffer so we prefer to put at the end of free
+				 * list. */
+				LIST_ADDQ(&dss->free_sess, &ds->list);
+				ads = ds;
+			}
+		}
+
+		/* we didn't find a session avalaible with large enough room */
+		if (!ads) {
+			/* allocate a new session */
+			ads = dns_session_new(dss);
+			if (ads) {
+				/* ring is empty so this ring_write should never fail */
+				ring_write(&ads->ring, DNS_TCP_MSG_MAX_SIZE, NULL, 0, &myist, 1);
+				ads->nb_queries++;
+				LIST_ADD(&dss->free_sess, &ads->list);
+			}
+			else
+				ns->counters->snd_error++;
+		}
+
+		if (ads)
+			ns->counters->sent++;
+
+		ofs += cnt + len;
+	}
+
+	HA_ATOMIC_ADD(b_peek(buf, ofs), 1);
+	ofs += ring->ofs;
+	dss->ofs_req = ofs;
+	HA_RWLOCK_RDUNLOCK(DNS_LOCK, &ring->lock);
+
+
+	HA_SPIN_UNLOCK(DNS_LOCK, &dss->lock);
+	return t;
+}
+
+/*
+ * Task used to consume response
+ * Note: upper layer callback is called
+ */
+static struct task *dns_process_rsp(struct task *t, void *context, unsigned short state)
+{
+	struct dns_nameserver *ns = (struct dns_nameserver *)context;
+
+	ns->process_responses(ns);
+
+	return t;
+}
+
+/* Function used to initialize an TCP nameserver */
+int dns_stream_init(struct dns_nameserver *ns, struct server *srv)
+{
+	struct dns_stream_server *dss = NULL;
+
+        dss = calloc(1, sizeof(*dss));
+        if (!dss) {
+		ha_alert("memory allocation error initializing dns tcp server '%s'.\n", srv->id);
+		goto out;
+	}
+
+	dss->srv = srv;
+	dss->maxconn = srv->maxconn;
+
+	dss->ofs_req = ~0; /* init ring offset */
+	dss->ring_req = ring_new(2*DNS_TCP_MSG_RING_MAX_SIZE);
+	if (!dss->ring_req) {
+		ha_alert("memory allocation error initializing the ring for dns tcp server '%s'.\n", srv->id);
+		goto out;
+	}
+	/* Create the task associated to the resolver target handling conns */
+	if ((dss->task_req = task_new(MAX_THREADS_MASK)) == NULL) {
+		ha_alert("memory allocation error initializing the ring for dns tcp server '%s'.\n", srv->id);
+		goto out;
+	}
+
+	/* Update task's parameters */
+	dss->task_req->process = dns_process_req;
+	dss->task_req->context = ns;
+
+	/* attach the task as reader */
+	if (!ring_attach(dss->ring_req)) {
+		/* mark server attached to the ring */
+		ha_alert("server '%s': too many watchers for ring. this should never happen.\n", srv->id);
+		goto out;
+	}
+
+	/* Create the task associated to the resolver target handling conns */
+	if ((dss->task_rsp = task_new(MAX_THREADS_MASK)) == NULL) {
+		ha_alert("memory allocation error initializing the ring for dns tcp server '%s'.\n", srv->id);
+		goto out;
+	}
+
+	/* Update task's parameters */
+	dss->task_rsp->process = dns_process_rsp;
+	dss->task_rsp->context = ns;
+
+	/* Create the task associated to the resolver target handling conns */
+	if ((dss->task_idle = task_new(MAX_THREADS_MASK)) == NULL) {
+		ha_alert("memory allocation error initializing the ring for dns tcp server '%s'.\n", srv->id);
+		goto out;
+	}
+
+	/* Update task's parameters */
+	dss->task_idle->process = dns_process_idle_exp;
+	dss->task_idle->context = dss;
+	dss->task_idle->expire = tick_add(now_ms, 5000);
+
+	/* let start the task to free idle conns immediatly */
+	task_queue(dss->task_idle);
+
+	LIST_INIT(&dss->free_sess);
+	LIST_INIT(&dss->idle_sess);
+	LIST_INIT(&dss->wait_sess);
+	HA_SPIN_INIT(&dss->lock);
+	ns->stream = dss;
+	return 0;
+out:
+	if (dss && dss->task_rsp)
+		task_destroy(dss->task_rsp);
+	if (dss && dss->task_req)
+		task_destroy(dss->task_req);
+	if (dss && dss->ring_req)
+		ring_free(dss->ring_req);
+
+	free(dss);
 	return -1;
 }