Upgrade connection to websocket and provision new connection

Signed-off-by: Aleksey Mikhaylov <[email protected]>

Author: ttaym

fw/connection.h

@@ -51,6 +51,14 @@ enum {
 	/* HTTPS */
 	Conn_HttpsClnt	= Conn_Clnt | TFW_FSM_HTTPS,
 	Conn_HttpsSrv	= Conn_Srv | TFW_FSM_HTTPS,
+
+	/* Websocket plain */
+	Conn_WsClnt	= Conn_HttpClnt | TFW_FSM_WS,
+	Conn_WsSrv	= Conn_HttpSrv | TFW_FSM_WS,
+
+	/* Websocket secure */
+	Conn_WssClnt	= Conn_HttpsClnt | TFW_FSM_WS,
+	Conn_WssSrv	= Conn_HttpsSrv | TFW_FSM_WS,
 };
 
 #define TFW_CONN_TYPE2IDX(t)	TFW_FSM_TYPE(t)
@@ -100,7 +108,7 @@ enum {
 	struct sock		*sk;			\
 	void			(*destructor)(void *);
 
-typedef struct TfwConn {
+typedef struct tfw_conn_t {
 	TFW_CONN_COMMON;
 } TfwConn;
 
@@ -199,7 +207,9 @@ enum {
 	/* Connection is in use or at least scheduled to be established. */
 	TFW_CONN_B_ACTIVE,
 	/* Connection is disconnected and stopped. */
-	TFW_CONN_B_STOPPED
+	TFW_CONN_B_STOPPED,
+	/* Mark connection as unavailable to schedulers */
+	TFW_CONN_B_UNSCHED
 };
 
 /**
@@ -297,6 +307,15 @@ tfw_srv_conn_restricted(TfwSrvConn *srv_conn)
 	return test_bit(TFW_CONN_B_RESEND, &srv_conn->flags);
 }
 
+/*
+ * Connection is unavailable to scheduler and may be removed from it
+ */
+static inline bool
+tfw_srv_conn_unscheduled(TfwSrvConn *srv_conn)
+{
+	return test_bit(TFW_CONN_B_UNSCHED, &srv_conn->flags);
+}
+
 /*
  * Tell if a connection has non-idempotent requests.
  */

fw/gfsm.h

@@ -84,6 +84,8 @@ enum {
 	/* Protocols */
 	TFW_FSM_HTTP,
 	TFW_FSM_HTTPS,
+	/* Not really a FSM */
+	TFW_FSM_WS,
 
 	/* Security rules enforcement. */
 	TFW_FSM_FRANG_REQ,
@@ -181,7 +183,7 @@ typedef struct {
 			  & ((TFW_GFSM_FSM_MASK << TFW_GFSM_FSM_SHIFT)	\
 			    | TFW_GFSM_STATE_MASK))
 
-typedef struct TfwConn TfwConn;
+typedef struct tfw_conn_t TfwConn;
 typedef int (*tfw_gfsm_handler_t)(TfwConn *conn, TfwFsmData *data);
 
 void tfw_gfsm_state_init(TfwGState *st, void *obj, int st0);

fw/http.c

@@ -2339,7 +2339,6 @@ static int
 tfw_http_conn_init(TfwConn *conn)
 {
 	T_DBG2("%s: conn=[%p]\n", __func__, conn);
-
 	if (TFW_CONN_TYPE(conn) & Conn_Srv) {
 		TfwSrvConn *srv_conn = (TfwSrvConn *)conn;
 		if (!list_empty(&srv_conn->fwd_queue)) {
@@ -5931,6 +5930,7 @@ tfw_http_resp_process(TfwConn *conn, TfwStream *stream, struct sk_buff *skb)
 	unsigned int chunks_unused, parsed;
 	TfwHttpReq *bad_req;
 	TfwHttpMsg *hmresp, *hmsib;
+	TfwHttpResp *resp;
 	TfwFsmData data_up;
 	bool conn_stop, filtout = false;
 
@@ -5953,6 +5953,7 @@ tfw_http_resp_process(TfwConn *conn, TfwStream *stream, struct sk_buff *skb)
 	parsed = 0;
 	hmsib = NULL;
 	hmresp = (TfwHttpMsg *)stream->msg;
+	resp = (TfwHttpResp *)hmresp;
 
 	r = ss_skb_process(skb, tfw_http_parse_resp, hmresp, &chunks_unused,
 			   &parsed);
@@ -6098,6 +6099,44 @@ tfw_http_resp_process(TfwConn *conn, TfwStream *stream, struct sk_buff *skb)
 		r = TFW_PASS;
 		goto next_resp;
 	}
+
+	/*
+	 * Upgrade client and server connection to websocket, remove it
+	 * from scheduler and provision new connection.
+	 *
+	 * TODO #755: set existent client and server connection to Conn_Ws*
+	 * when websocket proxing protocol will be implemented
+	 */
+	if (unlikely(test_bit(TFW_HTTP_B_CONN_UPGRADE, hmresp->flags)
+		     && test_bit(TFW_HTTP_B_UPGRADE_WEBSOCKET, hmresp->flags)
+		     && resp->status == 101))
+	{
+		TfwServer *srv = (TfwServer *)resp->conn->peer;
+		TfwSrvConn *srv_conn;
+
+		/* Cannot proceed with upgrade websocket due to error
+		 * in creation of new http connection. While it will not be
+		 * inherently erroneous to upgrade existing connection, but
+		 * we would pay for it with essentially dropping connection with
+		 * server. Better just drop upgrade request and
+		 * reestablish connection.
+		 */
+		if (!(srv_conn = tfw_sock_srv_new_conn(srv))) {
+			tfw_http_conn_error_log(conn, "Can't create new "
+						      "connection for websocket"
+						      " upgrade response");
+			return TFW_BLOCK;
+		}
+
+		set_bit(TFW_CONN_B_UNSCHED,
+			&((TfwSrvConn *)hmresp->conn)->flags);
+
+		tfw_sock_srv_conn_activate(srv, srv_conn);
+		tfw_sock_srv_connect_try(srv_conn);
+
+		srv->sg->sched->upd_srv(srv);
+	}
+
 	/*
 	 * Pass the response to cache for further processing.
 	 * In the end, the response is sent on to the client.

fw/http_frame.h

@@ -200,7 +200,7 @@ typedef struct {
 	unsigned char	data_off;
 } TfwH2Ctx;
 
-typedef struct TfwConn TfwConn;
+typedef struct tfw_conn_t TfwConn;
 
 int tfw_h2_init(void);
 void tfw_h2_cleanup(void);

fw/http_sched_hash.c

@@ -129,6 +129,7 @@ __is_conn_suitable(TfwSrvConn *conn, bool hmonitor)
 {
 	return (hmonitor || !tfw_srv_suspended((TfwServer *)conn->peer))
 		&& !tfw_srv_conn_restricted(conn)
+		&& !tfw_srv_conn_unscheduled(conn)
 		&& !tfw_srv_conn_busy(conn)
 		&& !tfw_srv_conn_queue_full(conn)
 		&& tfw_srv_conn_get_if_live(conn);
@@ -333,6 +334,8 @@ tfw_sched_hash_add_conns(TfwServer *srv, TfwHashConnList *cl, size_t *seed,
 
 	list_for_each_entry(conn, &srv->conn_list, list) {
 		unsigned long hash;
+		if (tfw_srv_conn_unscheduled(conn))
+			continue;
 		do {
 			hash = __hash_64(srv_hash ^ *seed);
 			*seed += seed_inc;
@@ -432,13 +435,38 @@ tfw_sched_hash_del_srv(TfwServer *srv)
 		call_rcu(&cl->rcu, tfw_sched_hash_put_srv_data);
 }
 
+static int
+tfw_sched_hash_upd_srv(TfwServer *srv)
+{
+	size_t size, seed, seed_inc = 0;
+	TfwHashConnList *cl = rcu_dereference_bh_check(srv->sched_data, 1);
+	TfwHashConnList *cl_copy;
+
+	seed = get_random_long();
+	seed_inc = get_random_int();
+
+	size = sizeof(TfwHashConnList) + srv->conn_n * sizeof(TfwHashConn);
+	if (!(cl_copy = kzalloc(size, GFP_ATOMIC)))
+		return -ENOMEM;
+
+	tfw_sched_hash_add_conns(srv, cl_copy, &seed, seed_inc);
+
+	rcu_assign_pointer(srv->sched_data, cl_copy);
+
+	if (cl)
+		call_rcu(&cl->rcu, tfw_sched_hash_put_srv_data);
+
+	return 0;
+}
+
 static TfwScheduler tfw_sched_hash = {
 	.name		= "hash",
 	.list		= LIST_HEAD_INIT(tfw_sched_hash.list),
 	.add_grp	= tfw_sched_hash_add_grp,
 	.del_grp	= tfw_sched_hash_del_grp,
 	.add_srv	= tfw_sched_hash_add_srv,
 	.del_srv	= tfw_sched_hash_del_srv,
+	.upd_srv	= tfw_sched_hash_upd_srv,
 	.sched_sg_conn	= tfw_sched_hash_get_sg_conn,
 	.sched_srv_conn	= tfw_sched_hash_get_srv_conn,
 };

fw/http_sched_ratio.c

@@ -30,6 +30,12 @@
 
 #define TFW_SCHED_RATIO_INTVL	(HZ / 20)	/* The timer periodicity. */
 
+typedef struct {
+	struct rcu_head		rcu;
+	size_t			conn_n;
+	TfwSrvConn		*conns[0];
+} TfwRatioSrvConnList;
+
 /**
  * Individual upstream server descriptor.
  *
@@ -38,17 +44,15 @@
  *
  * @rcu		- RCU control structure.
  * @srv		- pointer to server structure.
- * @conn	- list of pointers to server connection structures.
+ * @cl		- pointer to list of pointers to server connection structures.
  * @counter	- monotonic counter for choosing the next connection.
- * @conn_n	- number of connections to server.
  * @seq		- current sequence number for APM stats.
  */
 typedef struct {
 	struct rcu_head		rcu;
 	TfwServer		*srv;
-	TfwSrvConn		**conn;
+	TfwRatioSrvConnList	*cl;
 	atomic64_t		counter;
-	size_t			conn_n;
 	unsigned int		seq;
 } TfwRatioSrvDesc;
 
@@ -827,12 +831,15 @@ static inline TfwSrvConn *
 __sched_srv(TfwRatioSrvDesc *srvdesc, int skipnip, int *nipconn)
 {
 	size_t ci;
+	TfwRatioSrvConnList *cl = rcu_dereference_bh_check(srvdesc->cl, 1);
 
-	for (ci = 0; ci < srvdesc->conn_n; ++ci) {
+	rcu_read_lock_bh();
+	for (ci = 0; ci < cl->conn_n; ++ci) {
 		unsigned long idxval = atomic64_inc_return(&srvdesc->counter);
-		TfwSrvConn *srv_conn = srvdesc->conn[idxval % srvdesc->conn_n];
+		TfwSrvConn *srv_conn = cl->conns[idxval % cl->conn_n];
 
 		if (unlikely(tfw_srv_conn_restricted(srv_conn)
+			     || tfw_srv_conn_unscheduled(srv_conn)
 			     || tfw_srv_conn_busy(srv_conn)
 			     || tfw_srv_conn_queue_full(srv_conn)))
 			continue;
@@ -841,9 +848,12 @@ __sched_srv(TfwRatioSrvDesc *srvdesc, int skipnip, int *nipconn)
 				++(*nipconn);
 			continue;
 		}
-		if (likely(tfw_srv_conn_get_if_live(srv_conn)))
+		if (likely(tfw_srv_conn_get_if_live(srv_conn))) {
+			rcu_read_unlock_bh();
 			return srv_conn;
+		}
 	}
+	rcu_read_unlock_bh();
 
 	return NULL;
 }
@@ -981,7 +991,7 @@ tfw_sched_ratio_cleanup(TfwRatio *ratio)
 
 	/* Data that is shared between pool entries. */
 	for (si = 0; si < ratio->srv_n; ++si)
-		kfree(ratio->srvdesc[si].conn);
+		kfree(ratio->srvdesc[si].cl);
 
 	kfree(ratio->hstdata);
 	kfree(ratio->rtodata);
@@ -1039,28 +1049,32 @@ static int
 tfw_sched_ratio_srvdesc_setup_srv(TfwServer *srv, TfwRatioSrvDesc *srvdesc)
 {
 	size_t size, ci = 0;
-	TfwSrvConn **conn, *srv_conn;
+	TfwSrvConn *srv_conn;
+	TfwRatioSrvConnList *cl;
 
-	size = sizeof(TfwSrvConn *) * srv->conn_n;
-	if (!(srvdesc->conn = kzalloc(size, GFP_KERNEL)))
+	size = sizeof(TfwRatioSrvConnList) + sizeof(TfwSrvConn *) * srv->conn_n;
+	if (!(cl = kzalloc(size, GFP_KERNEL)))
 		return -ENOMEM;
 
-	conn = srvdesc->conn;
 	list_for_each_entry(srv_conn, &srv->conn_list, list) {
+		if (tfw_srv_conn_unscheduled(srv_conn))
+			continue;
 		if (unlikely(ci++ == srv->conn_n))
 			goto err;
-		*conn++ = srv_conn;
+
+		cl->conns[ci-1] = srv_conn;
 	}
 	if (unlikely(ci != srv->conn_n))
 		goto err;
 
-	srvdesc->conn_n = srv->conn_n;
+	cl->conn_n = ci;
 	srvdesc->srv = srv;
 	atomic64_set(&srvdesc->counter, 0);
 
+	rcu_assign_pointer(srvdesc->cl, cl);
 	return 0;
 err:
-	kfree(srvdesc->conn);
+	kfree(srvdesc->cl);
 	return -EINVAL;
 }
 
@@ -1081,7 +1095,7 @@ tfw_sched_ratio_srvdesc_setup(TfwSrvGroup *sg, TfwRatio *ratio)
 	int r;
 	size_t si = 0;
 	TfwServer *srv;
-	TfwRatioSrvDesc *srvdesc = ratio->srvdesc;
+	TfwRatioSrvDesc *srvdesc = rcu_dereference_bh_check(ratio->srvdesc, 1);
 
 	list_for_each_entry(srv, &sg->srv_list, list) {
 		if (unlikely((si++ == sg->srv_n) || !srv->conn_n
@@ -1277,10 +1291,17 @@ static void
 tfw_sched_ratio_put_srv_data(struct rcu_head *rcu)
 {
 	TfwRatioSrvDesc *srvdesc = container_of(rcu, TfwRatioSrvDesc, rcu);
-	kfree(srvdesc->conn);
+	kfree(srvdesc->cl);
 	kfree(srvdesc);
 }
 
+static void
+tfw_sched_ratio_put_conn_data(struct rcu_head *rcu)
+{
+	TfwRatioSrvConnList *cl = container_of(rcu, TfwRatioSrvConnList, rcu);
+	kfree(cl);
+}
+
 static void
 tfw_sched_ratio_del_srv(TfwServer *srv)
 {
@@ -1291,13 +1312,48 @@ tfw_sched_ratio_del_srv(TfwServer *srv)
 		call_rcu(&srvdesc->rcu, tfw_sched_ratio_put_srv_data);
 }
 
+static int
+tfw_sched_ratio_upd_srv(TfwServer *srv)
+{
+	TfwRatioSrvDesc *srvdesc = rcu_dereference_bh_check(srv->sched_data, 1);
+	size_t size, ci = 0;
+	TfwRatioSrvConnList *cl_copy;
+	TfwRatioSrvConnList *cl = rcu_dereference_bh_check(srvdesc->cl, 1);
+	TfwSrvConn *srv_conn;
+
+	size = sizeof(TfwRatioSrvConnList) + sizeof(TfwSrvConn *) * srv->conn_n;
+	if (!(cl_copy = kzalloc(size, GFP_ATOMIC)))
+		return -ENOMEM;
+
+	list_for_each_entry(srv_conn, &srv->conn_list, list) {
+		if (tfw_srv_conn_unscheduled(srv_conn))
+			continue;
+		if (unlikely(ci++ == srv->conn_n))
+			goto err;
+		cl_copy->conns[ci-1] = srv_conn;
+	}
+	if (unlikely(ci != srv->conn_n))
+		goto err;
+	cl->conn_n = ci;
+	rcu_assign_pointer(srvdesc->cl, cl_copy);
+
+	if (srvdesc)
+		call_rcu(&cl->rcu, tfw_sched_ratio_put_conn_data);
+
+	return 0;
+err:
+	kfree(cl_copy);
+	return -EINVAL;
+}
+
 static TfwScheduler tfw_sched_ratio = {
 	.name		= "ratio",
 	.list		= LIST_HEAD_INIT(tfw_sched_ratio.list),
 	.add_grp	= tfw_sched_ratio_add_grp,
 	.del_grp	= tfw_sched_ratio_del_grp,
 	.add_srv	= tfw_sched_ratio_add_srv,
 	.del_srv	= tfw_sched_ratio_del_srv,
+	.upd_srv	= tfw_sched_ratio_upd_srv,
 	.sched_sg_conn	= tfw_sched_ratio_sched_sg_conn,
 	.sched_srv_conn	= tfw_sched_ratio_sched_srv_conn,
 };