afb-stub-ws: Allow unordered process of messages
[src/app-framework-binder.git] / src / afb-stub-ws.c
index d1ce80b..eab897b 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2015, 2016, 2017 "IoT.bzh"
+ * Copyright (C) 2015-2018 "IoT.bzh"
  * Author José Bollo <jose.bollo@iot.bzh>
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -17,8 +17,6 @@
 
 #define _GNU_SOURCE
 
-#define NO_PLUGIN_VERBOSE_MACRO
-
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
 #include <pthread.h>
 
 #include <json-c/json.h>
-#include <systemd/sd-event.h>
-
-#include <afb/afb-event-itf.h>
 
-#include "afb-common.h"
+#include <afb/afb-event-x2.h>
 
 #include "afb-session.h"
 #include "afb-cred.h"
 #include "afb-evt.h"
 #include "afb-xreq.h"
 #include "verbose.h"
+#include "fdev.h"
 #include "jobs.h"
 
 struct afb_stub_ws;
 
 
-/******************* handling subcalls *****************************/
-
 /**
- * Structure on server side for recording pending
- * subcalls.
- */
-struct server_subcall
-{
-       struct server_subcall *next;    /**< next subcall for the client */
-       uint32_t subcallid;             /**< the subcallid */
-       void (*callback)(void*, int, struct json_object*); /**< callback on completion */
-       void *closure;                  /**< closure of the callback */
-};
-
-/**
- * Structure for sending back replies on client side
- */
-struct client_subcall
-{
-       struct afb_stub_ws *stubws;     /**< stub descriptor */
-       uint32_t subcallid;             /**< subcallid for the reply */
-};
-
-/*
- * structure for recording calls on client side
- */
-struct client_call {
-       struct client_call *next;       /* the next call */
-       struct afb_stub_ws *stubws;     /* the stub_ws */
-       struct afb_xreq *xreq;          /* the request handle */
-       uint32_t msgid;                 /* the message identifier */
-};
-
-/*
- * structure for a ws request
+ * structure for a ws request: requests on server side
  */
 struct server_req {
-       struct afb_xreq xreq;           /* the xreq */
-       struct afb_stub_ws *stubws;     /* the client of the request */
-       struct afb_proto_ws_call *call; /* the incoming call */
+       struct afb_xreq xreq;           /**< the xreq */
+       struct afb_stub_ws *stubws;     /**< the client of the request */
+       struct afb_proto_ws_call *call; /**< the incoming call */
 };
 
-/*
+/**
  * structure for recording events on client side
  */
 struct client_event
 {
-       struct client_event *next;
-       struct afb_event event;
-       int eventid;
-       int refcount;
+       struct client_event *next;      /**< link to the next */
+       struct afb_event_x2 *event;     /**< the local event */
+       int id;                         /**< the identifier */
+       int refcount;                   /**< a reference count */
 };
 
-/*
- * structure for recording describe requests
+/**
+ * structure for recording describe requests on the client side
  */
 struct client_describe
 {
-       struct afb_stub_ws *stubws;
-       struct jobloop *jobloop;
-       struct json_object *result;
+       struct afb_stub_ws *stubws;     /**< the stub */
+       struct jobloop *jobloop;        /**< the jobloop to leave */
+       struct json_object *result;     /**< result */
 };
 
-/*
+/**
  * structure for jobs of describing
  */
 struct server_describe
@@ -126,38 +89,67 @@ struct server_describe
        struct afb_proto_ws_describe *describe;
 };
 
+/**
+ * structure for recording sessions
+ */
+struct server_session
+{
+       struct server_session *next;
+       struct afb_session *session;
+};
+
 /******************* stub description for client or servers ******************/
 
 struct afb_stub_ws
 {
-       /* count of references */
-       int refcount;
-
-       /* resource control */
-       pthread_mutex_t mutex;
-
        /* protocol */
        struct afb_proto_ws *proto;
 
-       /* listener for events (server side) */
-       struct afb_evt_listener *listener;
-
-       /* event replica (client side) */
-       struct client_event *events;
-
-       /* credentials (server side) */
-       struct afb_cred *cred;
-
        /* apiset */
        struct afb_apiset *apiset;
 
        /* on hangup callback */
        void (*on_hangup)(struct afb_stub_ws *);
 
+       union {
+               /* server side */
+               struct {
+                       /* listener for events */
+                       struct afb_evt_listener *listener;
+
+                       /* sessions */
+                       struct server_session *sessions;
+
+                       /* credentials of the client */
+                       struct afb_cred *cred;
+               };
+
+               /* client side */
+               struct {
+                       /* event replica  */
+                       struct client_event *events;
+
+                       /* robustify */
+                       struct {
+                               struct fdev *(*reopen)(void*);
+                               void *closure;
+                               void (*release)(void*);
+                       } robust;
+               };
+       };
+
+       /* count of references */
+       unsigned refcount;
+
+       /* type of the stub: 0=server, 1=client */
+       uint8_t is_client;
+
        /* the api name */
        char apiname[1];
 };
 
+static struct afb_proto_ws *afb_stub_ws_create_proto(struct afb_stub_ws *stubws, struct fdev *fdev, uint8_t server);
+
 /******************* ws request part for server *****************/
 
 /* decrement the reference count of the request and free/release it on falling to null */
@@ -173,57 +165,37 @@ static void server_req_destroy_cb(struct afb_xreq *xreq)
        free(wreq);
 }
 
-static void server_req_success_cb(struct afb_xreq *xreq, struct json_object *obj, const char *info)
+static void server_req_reply_cb(struct afb_xreq *xreq, struct json_object *obj, const char *error, const char *info)
 {
        int rc;
        struct server_req *wreq = CONTAINER_OF_XREQ(struct server_req, xreq);
 
-       rc = afb_proto_ws_call_success(wreq->call, obj, info);
+       rc = afb_proto_ws_call_reply(wreq->call, obj, error, info);
        if (rc < 0)
-               ERROR("error while sending success");
+               ERROR("error while sending reply");
        json_object_put(obj);
 }
 
-static void server_req_fail_cb(struct afb_xreq *xreq, const char *status, const char *info)
+static int server_req_subscribe_cb(struct afb_xreq *xreq, struct afb_event_x2 *event)
 {
        int rc;
        struct server_req *wreq = CONTAINER_OF_XREQ(struct server_req, xreq);
 
-       rc = afb_proto_ws_call_fail(wreq->call, status, info);
-       if (rc < 0)
-               ERROR("error while sending fail");
-}
-
-static void server_req_subcall_cb(struct afb_xreq *xreq, const char *api, const char *verb, struct json_object *args, void (*callback)(void*, int, struct json_object*), void *cb_closure)
-{
-       int rc;
-       struct server_req *wreq = CONTAINER_OF_XREQ(struct server_req, xreq);
-
-       rc = afb_proto_ws_call_subcall(wreq->call, api, verb, args, callback, cb_closure);
-       if (rc < 0)
-               ERROR("error while sending subcall");
-}
-
-static int server_req_subscribe_cb(struct afb_xreq *xreq, struct afb_event event)
-{
-       int rc;
-       struct server_req *wreq = CONTAINER_OF_XREQ(struct server_req, xreq);
-
-       rc = afb_evt_add_watch(wreq->stubws->listener, event);
+       rc = afb_evt_event_x2_add_watch(wreq->stubws->listener, event);
        if (rc >= 0)
-               rc = afb_proto_ws_call_subscribe(wreq->call,  afb_evt_event_fullname(event), afb_evt_event_id(event));
+               rc = afb_proto_ws_call_subscribe(wreq->call,  afb_evt_event_x2_fullname(event), afb_evt_event_x2_id(event));
        if (rc < 0)
                ERROR("error while subscribing event");
        return rc;
 }
 
-static int server_req_unsubscribe_cb(struct afb_xreq *xreq, struct afb_event event)
+static int server_req_unsubscribe_cb(struct afb_xreq *xreq, struct afb_event_x2 *event)
 {
        int rc, rc2;
        struct server_req *wreq = CONTAINER_OF_XREQ(struct server_req, xreq);
 
-       rc = afb_proto_ws_call_unsubscribe(wreq->call,  afb_evt_event_fullname(event), afb_evt_event_id(event));
-       rc2 = afb_evt_remove_watch(wreq->stubws->listener, event);
+       rc = afb_proto_ws_call_unsubscribe(wreq->call,  afb_evt_event_x2_fullname(event), afb_evt_event_x2_id(event));
+       rc2 = afb_evt_event_x2_remove_watch(wreq->stubws->listener, event);
        if (rc >= 0 && rc2 < 0)
                rc = rc2;
        if (rc < 0)
@@ -232,35 +204,80 @@ static int server_req_unsubscribe_cb(struct afb_xreq *xreq, struct afb_event eve
 }
 
 static const struct afb_xreq_query_itf server_req_xreq_itf = {
-       .success = server_req_success_cb,
-       .fail = server_req_fail_cb,
+       .reply = server_req_reply_cb,
        .unref = server_req_destroy_cb,
-       .subcall = server_req_subcall_cb,
        .subscribe = server_req_subscribe_cb,
        .unsubscribe = server_req_unsubscribe_cb
 };
 
 /******************* client part **********************************/
 
+/* destroy all events */
+static void client_drop_all_events(struct afb_stub_ws *stubws)
+{
+       struct client_event *ev, *nxt;
+
+       nxt = __atomic_exchange_n(&stubws->events, NULL, __ATOMIC_RELAXED);
+       while (nxt) {
+               ev = nxt;
+               nxt = ev->next;
+               afb_evt_event_x2_unref(ev->event);
+               free(ev);
+       }
+}
+
 /* search the event */
 static struct client_event *client_event_search(struct afb_stub_ws *stubws, uint32_t eventid, const char *name)
 {
        struct client_event *ev;
 
        ev = stubws->events;
-       while (ev != NULL && (ev->eventid != eventid || 0 != strcmp(afb_evt_event_fullname(ev->event), name)))
+       while (ev != NULL && (ev->id != eventid || 0 != strcmp(afb_evt_event_x2_fullname(ev->event), name)))
                ev = ev->next;
 
+       DEBUG("searching event %s[%d]: %s", name, eventid, ev ? "found" : "not found");
        return ev;
 }
 
+static struct afb_proto_ws *client_get_proto(struct afb_stub_ws *stubws)
+{
+       struct fdev *fdev;
+       struct afb_proto_ws *proto;
+
+       proto = stubws->proto;
+       if (proto == NULL && stubws->robust.reopen) {
+               fdev = stubws->robust.reopen(stubws->robust.closure);
+               if (fdev != NULL)
+                       proto = afb_stub_ws_create_proto(stubws, fdev, 0);
+       }
+       return proto;
+}
+
 /* on call, propagate it to the ws service */
-static void client_call_cb(void * closure, struct afb_xreq *xreq)
+static void client_api_call_cb(void * closure, struct afb_xreq *xreq)
 {
+       int rc;
        struct afb_stub_ws *stubws = closure;
+       struct afb_proto_ws *proto;
+
+       proto = client_get_proto(stubws);
+       if (proto == NULL) {
+               afb_xreq_reply(xreq, NULL, "disconnected", "server hung up");
+               return;
+       }
 
-       afb_proto_ws_client_call(stubws->proto, xreq->verb, afb_xreq_json(xreq), afb_session_uuid(xreq->context.session), xreq);
        afb_xreq_unhooked_addref(xreq);
+       rc = afb_proto_ws_client_call(
+                       proto,
+                       xreq->request.called_verb,
+                       afb_xreq_json(xreq),
+                       afb_session_uuid(xreq->context.session),
+                       xreq,
+                       xreq_on_behalf_cred_export(xreq));
+       if (rc < 0) {
+               afb_xreq_reply(xreq, NULL, "internal", "can't send message");
+               afb_xreq_unhooked_unref(xreq);
+       }
 }
 
 static void client_on_description_cb(void *closure, struct json_object *data)
@@ -274,17 +291,19 @@ static void client_on_description_cb(void *closure, struct json_object *data)
 static void client_send_describe_cb(int signum, void *closure, struct jobloop *jobloop)
 {
        struct client_describe *desc = closure;
+       struct afb_proto_ws *proto;
 
-       if (signum)
+       proto = client_get_proto(desc->stubws);
+       if (signum || proto == NULL)
                jobs_leave(jobloop);
        else {
                desc->jobloop = jobloop;
-               afb_proto_ws_client_describe(desc->stubws->proto, client_on_description_cb, desc);
+               afb_proto_ws_client_describe(proto, client_on_description_cb, desc);
        }
 }
 
 /* get the description */
-static struct json_object *client_describe_cb(void * closure)
+static struct json_object *client_api_describe_cb(void * closure)
 {
        struct client_describe desc;
 
@@ -297,55 +316,51 @@ static struct json_object *client_describe_cb(void * closure)
 
 /******************* server part: manage events **********************************/
 
-static void server_event_add(void *closure, const char *event, int eventid)
+static void server_event_add_cb(void *closure, const char *event, int eventid)
 {
        struct afb_stub_ws *stubws = closure;
 
-       afb_proto_ws_server_event_create(stubws->proto, event, eventid);
+       if (stubws->proto != NULL)
+               afb_proto_ws_server_event_create(stubws->proto, event, eventid);
 }
 
-static void server_event_remove(void *closure, const char *event, int eventid)
+static void server_event_remove_cb(void *closure, const char *event, int eventid)
 {
        struct afb_stub_ws *stubws = closure;
 
-       afb_proto_ws_server_event_remove(stubws->proto, event, eventid);
+       if (stubws->proto != NULL)
+               afb_proto_ws_server_event_remove(stubws->proto, event, eventid);
 }
 
-static void server_event_push(void *closure, const char *event, int eventid, struct json_object *object)
+static void server_event_push_cb(void *closure, const char *event, int eventid, struct json_object *object)
 {
        struct afb_stub_ws *stubws = closure;
 
-       afb_proto_ws_server_event_push(stubws->proto, event, eventid, object);
+       if (stubws->proto != NULL)
+               afb_proto_ws_server_event_push(stubws->proto, event, eventid, object);
        json_object_put(object);
 }
 
-static void server_event_broadcast(void *closure, const char *event, int eventid, struct json_object *object)
+static void server_event_broadcast_cb(void *closure, const char *event, int eventid, struct json_object *object)
 {
        struct afb_stub_ws *stubws = closure;
 
-       afb_proto_ws_server_event_broadcast(stubws->proto, event, object);
+       if (stubws->proto != NULL)
+               afb_proto_ws_server_event_broadcast(stubws->proto, event, object);
        json_object_put(object);
 }
 
 /*****************************************************/
 
-static void on_reply_success(void *closure, void *request, struct json_object *result, const char *info)
-{
-       struct afb_xreq *xreq = request;
-
-       afb_xreq_success(xreq, result, *info ? info : NULL);
-       afb_xreq_unhooked_unref(xreq);
-}
-
-static void on_reply_fail(void *closure, void *request, const char *status, const char *info)
+static void client_on_reply_cb(void *closure, void *request, struct json_object *object, const char *error, const char *info)
 {
        struct afb_xreq *xreq = request;
 
-       afb_xreq_fail(xreq, status, *info ? info : NULL);
+       afb_xreq_reply(xreq, object, error, info);
        afb_xreq_unhooked_unref(xreq);
 }
 
-static void on_event_create(void *closure, const char *event_name, int event_id)
+static void client_on_event_create_cb(void *closure, const char *event_name, int event_id)
 {
        struct afb_stub_ws *stubws = closure;
        struct client_event *ev;
@@ -353,17 +368,17 @@ static void on_event_create(void *closure, const char *event_name, int event_id)
        /* check conflicts */
        ev = client_event_search(stubws, event_id, event_name);
        if (ev != NULL) {
-               ev->refcount++;
+               __atomic_add_fetch(&ev->refcount, 1, __ATOMIC_RELAXED);
                return;
        }
 
        /* no conflict, try to add it */
        ev = malloc(sizeof *ev);
        if (ev != NULL) {
-               ev->event = afb_evt_create_event(event_name);
-               if (ev->event.closure != NULL) {
+               ev->event = afb_evt_event_x2_create(event_name);
+               if (ev->event != NULL) {
                        ev->refcount = 1;
-                       ev->eventid = event_id;
+                       ev->id = event_id;
                        ev->next = stubws->events;
                        stubws->events = ev;
                        return;
@@ -373,7 +388,7 @@ static void on_event_create(void *closure, const char *event_name, int event_id)
        ERROR("can't create event %s, out of memory", event_name);
 }
 
-static void on_event_remove(void *closure, const char *event_name, int event_id)
+static void client_on_event_remove_cb(void *closure, const char *event_name, int event_id)
 {
        struct afb_stub_ws *stubws = closure;
        struct client_event *ev, **prv;
@@ -384,7 +399,8 @@ static void on_event_remove(void *closure, const char *event_name, int event_id)
                return;
 
        /* decrease the reference count */
-       if (--ev->refcount)
+
+       if (__atomic_sub_fetch(&ev->refcount, 1, __ATOMIC_RELAXED))
                return;
 
        /* unlinks the event */
@@ -394,11 +410,11 @@ static void on_event_remove(void *closure, const char *event_name, int event_id)
        *prv = ev->next;
 
        /* destroys the event */
-       afb_event_unref(ev->event);
+       afb_evt_event_x2_unref(ev->event);
        free(ev);
 }
 
-static void on_event_subscribe(void *closure, void *request, const char *event_name, int event_id)
+static void client_on_event_subscribe_cb(void *closure, void *request, const char *event_name, int event_id)
 {
        struct afb_stub_ws *stubws = closure;
        struct afb_xreq *xreq = request;
@@ -413,7 +429,7 @@ static void on_event_subscribe(void *closure, void *request, const char *event_n
                ERROR("can't subscribe: %m");
 }
 
-static void on_event_unsubscribe(void *closure, void *request, const char *event_name, int event_id)
+static void client_on_event_unsubscribe_cb(void *closure, void *request, const char *event_name, int event_id)
 {
        struct afb_stub_ws *stubws = closure;
        struct afb_xreq *xreq = request;
@@ -428,7 +444,7 @@ static void on_event_unsubscribe(void *closure, void *request, const char *event
                ERROR("can't unsubscribe: %m");
 }
 
-static void on_event_push(void *closure, const char *event_name, int event_id, struct json_object *data)
+static void client_on_event_push_cb(void *closure, const char *event_name, int event_id, struct json_object *data)
 {
        struct afb_stub_ws *stubws = closure;
        struct client_event *ev;
@@ -436,32 +452,61 @@ static void on_event_push(void *closure, const char *event_name, int event_id, s
        /* check conflicts */
        ev = client_event_search(stubws, event_id, event_name);
        if (ev)
-               afb_event_push(ev->event, data);
+               afb_evt_event_x2_push(ev->event, data);
        else
                ERROR("unreadable push event");
 }
 
-static void on_event_broadcast(void *closure, const char *event_name, struct json_object *data)
+static void client_on_event_broadcast_cb(void *closure, const char *event_name, struct json_object *data)
 {
        afb_evt_broadcast(event_name, data);
 }
 
-static void client_subcall_reply_cb(void *closure, int status, json_object *object)
+/*****************************************************/
+
+static void server_record_session(struct afb_stub_ws *stubws, struct afb_session *session)
 {
-       struct afb_proto_ws_subcall *subcall = closure;
-       afb_proto_ws_subcall_reply(subcall, status, object);
+       struct server_session *s, **prv;
+
+       /* search */
+       prv = &stubws->sessions;
+       while ((s = *prv)) {
+               if (s->session == session)
+                       return;
+               if (afb_session_is_closed(s->session)) {
+                       *prv = s->next;
+                       afb_session_unref(s->session);
+                       free(s);
+               }
+               else
+                       prv = &s->next;
+       }
+
+       /* create */
+       s = malloc(sizeof *s);
+       if (s) {
+               s->session = afb_session_addref(session);
+               s->next = stubws->sessions;
+               stubws->sessions = s;
+       }
 }
 
-static void on_subcall(void *closure, struct afb_proto_ws_subcall *subcall, void *request, const char *api, const char *verb, struct json_object *args)
+static void server_release_all_sessions(struct afb_stub_ws *stubws)
 {
-       struct afb_xreq *xreq = request;
+       struct server_session *ses, *nses;
 
-       afb_xreq_subcall(xreq, api, verb, args, client_subcall_reply_cb, subcall);
+       nses = __atomic_exchange_n(&stubws->sessions, NULL, __ATOMIC_RELAXED);
+       while(nses) {
+               ses = nses;
+               nses = ses->next;
+               afb_session_unref(ses->session);
+               free(ses);
+       }
 }
 
 /*****************************************************/
 
-static void on_call(void *closure, struct afb_proto_ws_call *call, const char *verb, struct json_object *args, const char *sessionid)
+static void server_on_call_cb(void *closure, struct afb_proto_ws_call *call, const char *verb, struct json_object *args, const char *sessionid, const char *user_creds)
 {
        struct afb_stub_ws *stubws = closure;
        struct server_req *wreq;
@@ -480,11 +525,15 @@ static void on_call(void *closure, struct afb_proto_ws_call *call, const char *v
        /* init the context */
        if (afb_context_connect(&wreq->xreq.context, sessionid, NULL) < 0)
                goto unconnected;
+       wreq->xreq.context.validated = 1;
+       server_record_session(stubws, wreq->xreq.context.session);
+       if (wreq->xreq.context.created)
+               afb_session_set_autoclose(wreq->xreq.context.session, 1);
 
        /* makes the call */
-       wreq->xreq.cred = afb_cred_addref(stubws->cred);
-       wreq->xreq.api = stubws->apiname;
-       wreq->xreq.verb = verb;
+       wreq->xreq.cred = afb_cred_mixed_on_behalf_import(stubws->cred, sessionid, user_creds);
+       wreq->xreq.request.called_api = stubws->apiname;
+       wreq->xreq.request.called_verb = verb;
        wreq->xreq.json = args;
        afb_xreq_process(&wreq->xreq, stubws->apiset);
        return;
@@ -494,11 +543,11 @@ unconnected:
 out_of_memory:
        json_object_put(args);
        afb_stub_ws_unref(stubws);
-       afb_proto_ws_call_fail(call, "internal-error", NULL);
+       afb_proto_ws_call_reply(call, NULL, "internal-error", NULL);
        afb_proto_ws_call_unref(call);
 }
 
-static void server_describe_sjob(int signum, void *closure)
+static void server_describe_cb(int signum, void *closure)
 {
        struct json_object *obj;
        struct server_describe *desc = closure;
@@ -514,11 +563,11 @@ static void server_describe_sjob(int signum, void *closure)
 
 static void server_describe_job(int signum, void *closure)
 {
-       server_describe_sjob(signum, closure);
+       server_describe_cb(signum, closure);
        free(closure);
 }
 
-static void on_describe(void *closure, struct afb_proto_ws_describe *describe)
+static void server_on_describe_cb(void *closure, struct afb_proto_ws_describe *describe)
 {
        struct server_describe *desc, sdesc;
        struct afb_stub_ws *stubws = closure;
@@ -532,77 +581,95 @@ static void on_describe(void *closure, struct afb_proto_ws_describe *describe)
        afb_stub_ws_addref(stubws);
 
        /* process */
-       if (desc == &sdesc)
-               jobs_call(NULL, 0, server_describe_sjob, desc);
-       else {
-               if (jobs_queue(NULL, 0, server_describe_job, desc) < 0)
-                       jobs_call(NULL, 0, server_describe_job, desc);
-       }
+       if (desc == &sdesc || jobs_queue(NULL, 0, server_describe_job, desc) < 0)
+               jobs_call(NULL, 0, server_describe_cb, desc);
 }
 
 /*****************************************************/
 
 static const struct afb_proto_ws_client_itf client_itf =
 {
-       .on_reply_success = on_reply_success,
-       .on_reply_fail = on_reply_fail,
-       .on_event_create = on_event_create,
-       .on_event_remove = on_event_remove,
-       .on_event_subscribe = on_event_subscribe,
-       .on_event_unsubscribe = on_event_unsubscribe,
-       .on_event_push = on_event_push,
-       .on_event_broadcast = on_event_broadcast,
-       .on_subcall = on_subcall
+       .on_reply = client_on_reply_cb,
+       .on_event_create = client_on_event_create_cb,
+       .on_event_remove = client_on_event_remove_cb,
+       .on_event_subscribe = client_on_event_subscribe_cb,
+       .on_event_unsubscribe = client_on_event_unsubscribe_cb,
+       .on_event_push = client_on_event_push_cb,
+       .on_event_broadcast = client_on_event_broadcast_cb,
 };
 
-static const struct afb_proto_ws_server_itf server_itf =
-{
-       .on_call = on_call,
-       .on_describe = on_describe
+static struct afb_api_itf client_api_itf = {
+       .call = client_api_call_cb,
+       .describe = client_api_describe_cb
 };
 
-static struct afb_api_itf ws_api_itf = {
-       .call = client_call_cb,
-       .describe = client_describe_cb
+static const struct afb_proto_ws_server_itf server_itf =
+{
+       .on_call = server_on_call_cb,
+       .on_describe = server_on_describe_cb
 };
 
 /* the interface for events pushing */
-static const struct afb_evt_itf server_evt_itf = {
-       .broadcast = server_event_broadcast,
-       .push = server_event_push,
-       .add = server_event_add,
-       .remove = server_event_remove
+static const struct afb_evt_itf server_event_itf = {
+       .broadcast = server_event_broadcast_cb,
+       .push = server_event_push_cb,
+       .add = server_event_add_cb,
+       .remove = server_event_remove_cb
 };
 
 /*****************************************************/
 
-static void drop_all_events(struct afb_stub_ws *stubws)
+/* disconnect */
+static void disconnect(struct afb_stub_ws *stubws)
 {
-       struct client_event *ev, *nxt;
-
-       ev = stubws->events;
-       stubws->events = NULL;
-
-       while (ev) {
-               nxt = ev->next;
-               afb_event_unref(ev->event);
-               free(ev);
-               ev = nxt;
+       afb_proto_ws_unref(__atomic_exchange_n(&stubws->proto, NULL, __ATOMIC_RELAXED));
+       if (stubws->is_client)
+               client_drop_all_events(stubws);
+       else {
+               afb_evt_listener_unref(__atomic_exchange_n(&stubws->listener, NULL, __ATOMIC_RELAXED));
+               afb_cred_unref(__atomic_exchange_n(&stubws->cred, NULL, __ATOMIC_RELAXED));
+               server_release_all_sessions(stubws);
        }
 }
 
+
 /* callback when receiving a hangup */
 static void on_hangup(void *closure)
 {
        struct afb_stub_ws *stubws = closure;
 
-       if (stubws->on_hangup)
-               stubws->on_hangup(stubws);
+       if (stubws->proto) {
+               afb_stub_ws_addref(stubws);
+               disconnect(stubws);
+               if (stubws->on_hangup)
+                       stubws->on_hangup(stubws);
+               afb_stub_ws_unref(stubws);
+       }
+}
+
+static int enqueue_processing(struct afb_proto_ws *proto, void (*callback)(int signum, void* arg), void *arg)
+{
+       return jobs_queue(NULL /* proto */, 0, callback, arg);
 }
 
 /*****************************************************/
 
-static struct afb_stub_ws *afb_stub_ws_create(int fd, const char *apiname, struct afb_apiset *apiset, int client)
+static struct afb_proto_ws *afb_stub_ws_create_proto(struct afb_stub_ws *stubws, struct fdev *fdev, uint8_t is_client)
+{
+       struct afb_proto_ws *proto;
+
+       stubws->proto = proto = is_client
+                 ? afb_proto_ws_create_client(fdev, &client_itf, stubws)
+                 : afb_proto_ws_create_server(fdev, &server_itf, stubws);
+       if (proto) {
+               afb_proto_ws_on_hangup(proto, on_hangup);
+               afb_proto_ws_set_queuing(proto, enqueue_processing);
+       }
+
+       return proto;
+}
+
+static struct afb_stub_ws *afb_stub_ws_create(struct fdev *fdev, const char *apiname, struct afb_apiset *apiset, uint8_t is_client)
 {
        struct afb_stub_ws *stubws;
 
@@ -610,35 +677,32 @@ static struct afb_stub_ws *afb_stub_ws_create(int fd, const char *apiname, struc
        if (stubws == NULL)
                errno = ENOMEM;
        else {
-               if (client)
-                       stubws->proto = afb_proto_ws_create_client(fd, &client_itf, stubws);
-               else
-                       stubws->proto = afb_proto_ws_create_server(fd, &server_itf, stubws);
-               if (stubws->proto != NULL) {
+               if (afb_stub_ws_create_proto(stubws, fdev, is_client)) {
+                       stubws->refcount = 1;
+                       stubws->is_client = is_client;
                        strcpy(stubws->apiname, apiname);
                        stubws->apiset = afb_apiset_addref(apiset);
-                       stubws->refcount = 1;
-                       afb_proto_ws_on_hangup(stubws->proto, on_hangup);
                        return stubws;
                }
                free(stubws);
        }
+       fdev_unref(fdev);
        return NULL;
 }
 
-struct afb_stub_ws *afb_stub_ws_create_client(int fd, const char *apiname, struct afb_apiset *apiset)
+struct afb_stub_ws *afb_stub_ws_create_client(struct fdev *fdev, const char *apiname, struct afb_apiset *apiset)
 {
-       return afb_stub_ws_create(fd, apiname, apiset, 1);
+       return afb_stub_ws_create(fdev, apiname, apiset, 1);
 }
 
-struct afb_stub_ws *afb_stub_ws_create_server(int fd, const char *apiname, struct afb_apiset *apiset)
+struct afb_stub_ws *afb_stub_ws_create_server(struct fdev *fdev, const char *apiname, struct afb_apiset *apiset)
 {
        struct afb_stub_ws *stubws;
 
-       stubws = afb_stub_ws_create(fd, apiname, apiset, 0);
+       stubws = afb_stub_ws_create(fdev, apiname, apiset, 0);
        if (stubws) {
-               stubws->cred = afb_cred_create_for_socket(fd);
-               stubws->listener = afb_evt_listener_create(&server_evt_itf, stubws);
+               stubws->cred = afb_cred_create_for_socket(fdev_fd(fdev));
+               stubws->listener = afb_evt_listener_create(&server_event_itf, stubws);
                if (stubws->listener != NULL)
                        return stubws;
                afb_stub_ws_unref(stubws);
@@ -648,11 +712,15 @@ struct afb_stub_ws *afb_stub_ws_create_server(int fd, const char *apiname, struc
 
 void afb_stub_ws_unref(struct afb_stub_ws *stubws)
 {
-       if (!__atomic_sub_fetch(&stubws->refcount, 1, __ATOMIC_RELAXED)) {
-               drop_all_events(stubws);
-               afb_evt_listener_unref(stubws->listener);
-               afb_proto_ws_unref(stubws->proto);
-               afb_cred_unref(stubws->cred);
+       if (stubws && !__atomic_sub_fetch(&stubws->refcount, 1, __ATOMIC_RELAXED)) {
+
+               if (stubws->is_client) {
+                       stubws->robust.reopen = NULL;
+                       if (stubws->robust.release)
+                               stubws->robust.release(stubws->robust.closure);
+               }
+
+               disconnect(stubws);
                afb_apiset_unref(stubws->apiset);
                free(stubws);
        }
@@ -663,7 +731,7 @@ void afb_stub_ws_addref(struct afb_stub_ws *stubws)
        __atomic_add_fetch(&stubws->refcount, 1, __ATOMIC_RELAXED);
 }
 
-void afb_stub_ws_on_hangup(struct afb_stub_ws *stubws, void (*on_hangup)(struct afb_stub_ws*))
+void afb_stub_ws_set_on_hangup(struct afb_stub_ws *stubws, void (*on_hangup)(struct afb_stub_ws*))
 {
        stubws->on_hangup = on_hangup;
 }
@@ -673,14 +741,14 @@ const char *afb_stub_ws_name(struct afb_stub_ws *stubws)
        return stubws->apiname;
 }
 
-struct afb_api afb_stub_ws_client_api(struct afb_stub_ws *stubws)
+struct afb_api_item afb_stub_ws_client_api(struct afb_stub_ws *stubws)
 {
-       struct afb_api api;
+       struct afb_api_item api;
 
-       assert(!stubws->listener); /* check client */
+       assert(stubws->is_client); /* check client */
        api.closure = stubws;
-       api.itf = &ws_api_itf;
-       api.group = NULL;
+       api.itf = &client_api_itf;
+       api.group = stubws; /* serialize for reconnections */
        return api;
 }
 
@@ -689,3 +757,14 @@ int afb_stub_ws_client_add(struct afb_stub_ws *stubws, struct afb_apiset *apiset
        return afb_apiset_add(apiset, stubws->apiname, afb_stub_ws_client_api(stubws));
 }
 
+void afb_stub_ws_client_robustify(struct afb_stub_ws *stubws, struct fdev *(*reopen)(void*), void *closure, void (*release)(void*))
+{
+       assert(stubws->is_client); /* check client */
+
+       if (stubws->robust.release)
+               stubws->robust.release(stubws->robust.closure);
+
+       stubws->robust.reopen = reopen;
+       stubws->robust.closure = closure;
+       stubws->robust.release = release;
+}