Adding upstream version 1.12.0.upstream/1.12.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

12 files changed, 2931 insertions, 0 deletions

diff --git a/web/server/Makefile.am b/web/server/Makefile.am
new file mode 100644
index 0000000..5860a5c
--- /dev/null
+++ b/web/server/Makefile.am
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+AUTOMAKE_OPTIONS = subdir-objects
+MAINTAINERCLEANFILES = $(srcdir)/Makefile.in
+
+SUBDIRS = \
+    static \
+    $(NULL)
+
+dist_noinst_DATA = \
+	README.md \
+	$(NULL)
diff --git a/web/server/README.md b/web/server/README.md
new file mode 100644
index 0000000..7d74c18
--- /dev/null
+++ b/web/server/README.md
@@ -0,0 +1,123 @@
+# Web server
+
+The Netdata web server runs as `static-threaded`, i.e. with a fixed, configurable number of threads.
+It uses non-blocking I/O and respects the `keep-alive` HTTP header to serve multiple HTTP requests via the same connection.
+
+## Configuration
+
+You can disable the web server by editing `netdata.conf` and setting:
+
+```
+[web]
+    mode = none
+```
+
+With the web server enabled, you can control the number of threads and sockets with the following settings:
+
+```
+[web]
+    web server threads = 4
+    web server max sockets = 512
+```
+
+The default number of processor threads is `min(cpu cores, 6)`.
+
+The `web server max sockets` setting is automatically adjusted to 50% of the max number of open files netdata is allowed to use (via `/etc/security/limits.conf` or systemd), to allow enough file descriptors to be available for data collection.
+
+### Binding netdata to multiple ports
+
+Netdata can bind to multiple IPs and ports, offering access to different services on each. Up to 100 sockets can be used (you can increase it at compile time with `CFLAGS="-DMAX_LISTEN_FDS=200" ./netdata-installer.sh ...`).
+
+The ports to bind are controlled via `[web].bind to`, like this:
+
+```
+[web]
+   default port = 19999
+   bind to = 127.0.0.1=dashboard 10.1.1.1:19998=management|netdata.conf hostname:19997=badges [::]:19996=streaming localhost:19995=registry *:http=dashboard unix:/tmp/netdata.sock
+```
+
+Using the above, netdata will bind to:
+
+- IPv4 127.0.0.1 at port 19999 (port was used from `default port`). Only the UI (dashboard) and the read API will be accessible on this port. 
+- IPv4 10.1.1.1 at port 19998. The management API and netdata.conf will be accessible on this port.
+- All the IPs `hostname` resolves to (both IPv4 and IPv6 depending on the resolved IPs) at port 19997. Only badges will be accessible on this port.
+- All IPv6 IPs at port 19996. Only metric streaming requests from other netdata agents will be accepted on this port.
+- All the IPs `localhost` resolves to (both IPv4 and IPv6 depending the resolved IPs) at port 19996. This port will only accept registry API requests.
+- All IPv4 and IPv6 IPs at port `http` as set in `/etc/services`. Only the UI (dashboard) and the read API will be accessible on this port. 
+- Unix domain socket `/tmp/netdata.sock`. All requests are serviceable on this socket.
+
+The option `[web].default port` is used when an entries in `[web].bind to` do not specify a port.
+
+Note that the access permissions specified with the `=request type|request type|...` format are available from version 1.12 onwards. 
+As shown in the example above, these permissions are optional, with the default being to permit all request types on the specified port. 
+The request types are strings identical to the `allow X from` directives of the access lists, i.e. `dashboard`, `streaming`, `registry`, `netdata.conf`, `badges` and `management`. 
+The access lists themselves and the general setting `allow connections from` in the next section are applied regardless of the ports that are configured to provide these services. 
+The API requests are serviced as follows:
+- `dashboard` gives access to the UI, the read API and badges API calls.
+- `badges` gives access only to the badges API calls.
+- `management` gives access only to the management API calls.
+
+### Access lists
+
+Netdata supports access lists in `netdata.conf`:
+
+```
+[web]
+	allow connections from = localhost *
+	allow dashboard from = localhost *
+	allow badges from = *
+	allow streaming from = *
+	allow netdata.conf from = localhost fd* 10.* 192.168.* 172.16.* 172.17.* 172.18.* 172.19.* 172.20.* 172.21.* 172.22.* 172.23.* 172.24.* 172.25.* 172.26.* 172.27.* 172.28.* 172.29.* 172.30.* 172.31.*
+	allow management from = localhost
+```
+
+`*` does string matches on the IPs of the clients.
+
+- `allow connections from` matches anyone that connects on the netdata port(s).
+   So, if someone is not allowed, it will be connected and disconnected immediately, without reading even
+   a single byte from its connection. This is a global settings with higher priority to any of the ones below.
+
+- `allow dashboard from` receives the request and examines if it is a static dashboard file or an API call the
+   dashboards do.
+
+- `allow badges from` checks if the API request is for a badge. Badges are not matched by `allow dashboard from`.
+
+- `allow streaming from` checks if the slave willing to stream metrics to this netdata is allowed.
+   This can be controlled per API KEY and MACHINE GUID in [stream.conf](../../streaming/stream.conf).
+   The setting in `netdata.conf` is checked before the ones in [stream.conf](../../streaming/stream.conf).
+
+- `allow netdata.conf from` checks the IP to allow `http://netdata.host:19999/netdata.conf`.
+   The IPs listed are all the private IPv4 addresses, including link local IPv6 addresses. Keep in mind that connections to netdata API ports are filtered by `allow connections from`. So, IPs allowed by `allow netdata.conf from` should also be allowed by `allow connections from`.
+
+- `allow management from` checks the IPs to allow API management calls. Management via the API is currently supported for [health](../api/health/#health-management-api)
+
+### Other netdata.conf [web] section options
+setting | default | info
+:------:|:-------:|:----
+ses max window | `15` | See [single exponential smoothing](../api/queries/des/)
+des max window | `15` | See [double exponential smoothing](../api/queries/des/)
+listen backlog | `4096` | The port backlog. Check `man 2 listen`.  
+web files owner | `netdata` | The user that owns the web static files. Netdata will refuse to serve a file that is not owned by this user, even if it has read access to that file. If the user given is not found, netdata will only serve files owned by user given in `run as user`. 
+web files group | `netdata` | If this is set, Netdata will check if the file is owned by this group and refuse to serve the file if it's not.
+disconnect idle clients after seconds | `60` | The time in seconds to disconnect web clients after being totally idle. 
+timeout for first request | `60` | How long to wait for a client to send a request before closing the socket. Prevents slow request attacks.
+accept a streaming request every seconds | `0` | Can be used to set a limit on how often a master Netdata server will accept streaming requests from the slaves in a [streaming and replication setup](../../streaming)
+respect do not track policy | `no` | If set to `yes`, will respect the client's browser preferences on storing cookies. 
+x-frame-options response header |  | [Avoid clickjacking attacks, by ensuring that the content is not embedded into other sites](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Frame-Options).
+enable gzip compression | `yes` | When set to `yes`, netdata web responses will be GZIP compressed, if the web client accepts such responses. 
+gzip compression strategy | `default` | Valid strategies are `default`, `filtered`, `huffman only`, `rle` and `fixed`
+gzip compression level | `3` | Valid levels are 1 (fastest) to 9 (best ratio)
+
+
+## DDoS protection
+
+If you publish your netdata to the internet, you may want to apply some protection against DDoS:
+
+1. Use the `static-threaded` web server (it is the default)
+2. Use reasonable `[web].web server max sockets` (the default is)
+3. Don't use all your cpu cores for netdata (lower `[web].web server threads`)
+4. Run netdata with a low process scheduling priority (the default is the lowest)
+5. If possible, proxy netdata via a full featured web server (nginx, apache, etc)
+
+
+[![analytics](https://www.google-analytics.com/collect?v=1&aip=1&t=pageview&_s=1&ds=github&dr=https%3A%2F%2Fgithub.com%2Fnetdata%2Fnetdata&dl=https%3A%2F%2Fmy-netdata.io%2Fgithub%2Fweb%2Fserver%2FREADME&_u=MAC~&cid=5792dfd7-8dc4-476b-af31-da2fdb9f93d2&tid=UA-64295674-3)]()
diff --git a/web/server/static/Makefile.am b/web/server/static/Makefile.am
new file mode 100644
index 0000000..90cc9ca
--- /dev/null
+++ b/web/server/static/Makefile.am
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+AUTOMAKE_OPTIONS = subdir-objects
+MAINTAINERCLEANFILES = $(srcdir)/Makefile.in
+
+SUBDIRS = \
+    $(NULL)
+
+dist_noinst_DATA = \
+	README.md \
+	$(NULL)
diff --git a/web/server/static/README.md b/web/server/static/README.md
new file mode 100644
index 0000000..653b364
--- /dev/null
+++ b/web/server/static/README.md
@@ -0,0 +1,10 @@
+# `static-threaded` web server
+
+The `static-threaded` web server spawns a fixed number of threads.
+All the threads are concurrently listening for web requests on the same sockets.
+The kernel distributes the incoming requests to them.
+
+Each thread uses non-blocking I/O so it can serve any number of web requests in parallel.
+
+This web server respects the `keep-alive` HTTP header to serve multiple HTTP requests via the same connection. 
+[![analytics](https://www.google-analytics.com/collect?v=1&aip=1&t=pageview&_s=1&ds=github&dr=https%3A%2F%2Fgithub.com%2Fnetdata%2Fnetdata&dl=https%3A%2F%2Fmy-netdata.io%2Fgithub%2Fweb%2Fserver%2Fstatic%2FREADME&_u=MAC~&cid=5792dfd7-8dc4-476b-af31-da2fdb9f93d2&tid=UA-64295674-3)]()
diff --git a/web/server/static/static-threaded.c b/web/server/static/static-threaded.c
new file mode 100644
index 0000000..56e726b
--- /dev/null
+++ b/web/server/static/static-threaded.c
@@ -0,0 +1,437 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#define WEB_SERVER_INTERNALS 1
+#include "static-threaded.h"
+
+int web_client_timeout = DEFAULT_DISCONNECT_IDLE_WEB_CLIENTS_AFTER_SECONDS;
+int web_client_first_request_timeout = DEFAULT_TIMEOUT_TO_RECEIVE_FIRST_WEB_REQUEST;
+long web_client_streaming_rate_t = 0L;
+
+// ----------------------------------------------------------------------------
+// high level web clients connection management
+
+static struct web_client *web_client_create_on_fd(int fd, const char *client_ip, const char *client_port, int port_acl) {
+    struct web_client *w;
+
+    w = web_client_get_from_cache_or_allocate();
+    w->ifd = w->ofd = fd;
+
+    strncpyz(w->client_ip, client_ip, sizeof(w->client_ip) - 1);
+    strncpyz(w->client_port, client_port, sizeof(w->client_port) - 1);
+
+    if(unlikely(!*w->client_ip))   strcpy(w->client_ip,   "-");
+    if(unlikely(!*w->client_port)) strcpy(w->client_port, "-");
+	w->port_acl = port_acl;
+
+    web_client_initialize_connection(w);
+    return(w);
+}
+
+// --------------------------------------------------------------------------------------
+// the main socket listener - STATIC-THREADED
+
+struct web_server_static_threaded_worker {
+    netdata_thread_t thread;
+
+    int id;
+    int running;
+
+    size_t max_sockets;
+
+    volatile size_t connected;
+    volatile size_t disconnected;
+    volatile size_t receptions;
+    volatile size_t sends;
+    volatile size_t max_concurrent;
+
+    volatile size_t files_read;
+    volatile size_t file_reads;
+};
+
+static long long static_threaded_workers_count = 1;
+
+static struct web_server_static_threaded_worker *static_workers_private_data = NULL;
+static __thread struct web_server_static_threaded_worker *worker_private = NULL;
+
+// ----------------------------------------------------------------------------
+
+static inline int web_server_check_client_status(struct web_client *w) {
+    if(unlikely(web_client_check_dead(w) || (!web_client_has_wait_receive(w) && !web_client_has_wait_send(w))))
+        return -1;
+
+    return 0;
+}
+
+// ----------------------------------------------------------------------------
+// web server files
+
+static void *web_server_file_add_callback(POLLINFO *pi, short int *events, void *data) {
+    struct web_client *w = (struct web_client *)data;
+
+    worker_private->files_read++;
+
+    debug(D_WEB_CLIENT, "%llu: ADDED FILE READ ON FD %d", w->id, pi->fd);
+    *events = POLLIN;
+    pi->data = w;
+    return w;
+}
+
+static void web_werver_file_del_callback(POLLINFO *pi) {
+    struct web_client *w = (struct web_client *)pi->data;
+    debug(D_WEB_CLIENT, "%llu: RELEASE FILE READ ON FD %d", w->id, pi->fd);
+
+    w->pollinfo_filecopy_slot = 0;
+
+    if(unlikely(!w->pollinfo_slot)) {
+        debug(D_WEB_CLIENT, "%llu: CROSS WEB CLIENT CLEANUP (iFD %d, oFD %d)", w->id, pi->fd, w->ofd);
+        web_client_release(w);
+    }
+}
+
+static int web_server_file_read_callback(POLLINFO *pi, short int *events) {
+    struct web_client *w = (struct web_client *)pi->data;
+
+    // if there is no POLLINFO linked to this, it means the client disconnected
+    // stop the file reading too
+    if(unlikely(!w->pollinfo_slot)) {
+        debug(D_WEB_CLIENT, "%llu: PREVENTED ATTEMPT TO READ FILE ON FD %d, ON CLOSED WEB CLIENT", w->id, pi->fd);
+        return -1;
+    }
+
+    if(unlikely(w->mode != WEB_CLIENT_MODE_FILECOPY || w->ifd == w->ofd)) {
+        debug(D_WEB_CLIENT, "%llu: PREVENTED ATTEMPT TO READ FILE ON FD %d, ON NON-FILECOPY WEB CLIENT", w->id, pi->fd);
+        return -1;
+    }
+
+    debug(D_WEB_CLIENT, "%llu: READING FILE ON FD %d", w->id, pi->fd);
+
+    worker_private->file_reads++;
+    ssize_t ret = unlikely(web_client_read_file(w));
+
+    if(likely(web_client_has_wait_send(w))) {
+        POLLJOB *p = pi->p;                                        // our POLLJOB
+        POLLINFO *wpi = pollinfo_from_slot(p, w->pollinfo_slot);  // POLLINFO of the client socket
+
+        debug(D_WEB_CLIENT, "%llu: SIGNALING W TO SEND (iFD %d, oFD %d)", w->id, pi->fd, wpi->fd);
+        p->fds[wpi->slot].events |= POLLOUT;
+    }
+
+    if(unlikely(ret <= 0 || w->ifd == w->ofd)) {
+        debug(D_WEB_CLIENT, "%llu: DONE READING FILE ON FD %d", w->id, pi->fd);
+        return -1;
+    }
+
+    *events = POLLIN;
+    return 0;
+}
+
+static int web_server_file_write_callback(POLLINFO *pi, short int *events) {
+    (void)pi;
+    (void)events;
+
+    error("Writing to web files is not supported!");
+
+    return -1;
+}
+
+// ----------------------------------------------------------------------------
+// web server clients
+
+static void *web_server_add_callback(POLLINFO *pi, short int *events, void *data) {
+    (void)data;
+
+    worker_private->connected++;
+
+    size_t concurrent = worker_private->connected - worker_private->disconnected;
+    if(unlikely(concurrent > worker_private->max_concurrent))
+        worker_private->max_concurrent = concurrent;
+
+    *events = POLLIN;
+
+    debug(D_WEB_CLIENT_ACCESS, "LISTENER on %d: new connection.", pi->fd);
+    struct web_client *w = web_client_create_on_fd(pi->fd, pi->client_ip, pi->client_port, pi->port_acl);
+    w->pollinfo_slot = pi->slot;
+
+    if(unlikely(pi->socktype == AF_UNIX))
+        web_client_set_unix(w);
+    else
+        web_client_set_tcp(w);
+
+    debug(D_WEB_CLIENT, "%llu: ADDED CLIENT FD %d", w->id, pi->fd);
+    return w;
+}
+
+// TCP client disconnected
+static void web_server_del_callback(POLLINFO *pi) {
+    worker_private->disconnected++;
+
+    struct web_client *w = (struct web_client *)pi->data;
+
+    w->pollinfo_slot = 0;
+    if(unlikely(w->pollinfo_filecopy_slot)) {
+        POLLINFO *fpi = pollinfo_from_slot(pi->p, w->pollinfo_filecopy_slot);  // POLLINFO of the client socket
+        (void)fpi;
+
+        debug(D_WEB_CLIENT, "%llu: THE CLIENT WILL BE FRED BY READING FILE JOB ON FD %d", w->id, fpi->fd);
+    }
+    else {
+        if(web_client_flag_check(w, WEB_CLIENT_FLAG_DONT_CLOSE_SOCKET))
+            pi->flags |= POLLINFO_FLAG_DONT_CLOSE;
+
+        debug(D_WEB_CLIENT, "%llu: CLOSING CLIENT FD %d", w->id, pi->fd);
+        web_client_release(w);
+    }
+}
+
+static int web_server_rcv_callback(POLLINFO *pi, short int *events) {
+    worker_private->receptions++;
+
+    struct web_client *w = (struct web_client *)pi->data;
+    int fd = pi->fd;
+
+    if(unlikely(web_client_receive(w) < 0))
+        return -1;
+
+    debug(D_WEB_CLIENT, "%llu: processing received data on fd %d.", w->id, fd);
+    web_client_process_request(w);
+
+    if(unlikely(w->mode == WEB_CLIENT_MODE_FILECOPY)) {
+        if(w->pollinfo_filecopy_slot == 0) {
+            debug(D_WEB_CLIENT, "%llu: FILECOPY DETECTED ON FD %d", w->id, pi->fd);
+
+            if (unlikely(w->ifd != -1 && w->ifd != w->ofd && w->ifd != fd)) {
+                // add a new socket to poll_events, with the same
+                debug(D_WEB_CLIENT, "%llu: CREATING FILECOPY SLOT ON FD %d", w->id, pi->fd);
+
+                POLLINFO *fpi = poll_add_fd(
+                        pi->p
+                        , w->ifd
+                        , pi->port_acl
+                        , 0
+                        , POLLINFO_FLAG_CLIENT_SOCKET
+                        , "FILENAME"
+                        , ""
+                        , web_server_file_add_callback
+                        , web_werver_file_del_callback
+                        , web_server_file_read_callback
+                        , web_server_file_write_callback
+                        , (void *) w
+                );
+
+                if(fpi)
+                    w->pollinfo_filecopy_slot = fpi->slot;
+                else {
+                    error("Failed to add filecopy fd. Closing client.");
+                    return -1;
+                }
+            }
+        }
+    }
+    else {
+        if(unlikely(w->ifd == fd && web_client_has_wait_receive(w)))
+            *events |= POLLIN;
+    }
+
+    if(unlikely(w->ofd == fd && web_client_has_wait_send(w)))
+        *events |= POLLOUT;
+
+    return web_server_check_client_status(w);
+}
+
+static int web_server_snd_callback(POLLINFO *pi, short int *events) {
+    worker_private->sends++;
+
+    struct web_client *w = (struct web_client *)pi->data;
+    int fd = pi->fd;
+
+    debug(D_WEB_CLIENT, "%llu: sending data on fd %d.", w->id, fd);
+
+    if(unlikely(web_client_send(w) < 0))
+        return -1;
+
+    if(unlikely(w->ifd == fd && web_client_has_wait_receive(w)))
+        *events |= POLLIN;
+
+    if(unlikely(w->ofd == fd && web_client_has_wait_send(w)))
+        *events |= POLLOUT;
+
+    return web_server_check_client_status(w);
+}
+
+static void web_server_tmr_callback(void *timer_data) {
+    worker_private = (struct web_server_static_threaded_worker *)timer_data;
+
+    static __thread RRDSET *st = NULL;
+    static __thread RRDDIM *rd_user = NULL, *rd_system = NULL;
+
+    if(unlikely(!st)) {
+        char id[100 + 1];
+        char title[100 + 1];
+
+        snprintfz(id, 100, "web_thread%d_cpu", worker_private->id + 1);
+        snprintfz(title, 100, "NetData web server thread No %d CPU usage", worker_private->id + 1);
+
+        st = rrdset_create_localhost(
+                "netdata"
+                , id
+                , NULL
+                , "web"
+                , "netdata.web_cpu"
+                , title
+                , "milliseconds/s"
+                , "web"
+                , "stats"
+                , 132000 + worker_private->id
+                , default_rrd_update_every
+                , RRDSET_TYPE_STACKED
+        );
+
+        rd_user   = rrddim_add(st, "user", NULL, 1, 1000, RRD_ALGORITHM_INCREMENTAL);
+        rd_system = rrddim_add(st, "system", NULL, 1, 1000, RRD_ALGORITHM_INCREMENTAL);
+    }
+    else
+        rrdset_next(st);
+
+    struct rusage rusage;
+    getrusage(RUSAGE_THREAD, &rusage);
+    rrddim_set_by_pointer(st, rd_user, rusage.ru_utime.tv_sec * 1000000ULL + rusage.ru_utime.tv_usec);
+    rrddim_set_by_pointer(st, rd_system, rusage.ru_stime.tv_sec * 1000000ULL + rusage.ru_stime.tv_usec);
+    rrdset_done(st);
+}
+
+// ----------------------------------------------------------------------------
+// web server worker thread
+
+static void socket_listen_main_static_threaded_worker_cleanup(void *ptr) {
+    worker_private = (struct web_server_static_threaded_worker *)ptr;
+
+    info("freeing local web clients cache...");
+    web_client_cache_destroy();
+
+    info("stopped after %zu connects, %zu disconnects (max concurrent %zu), %zu receptions and %zu sends",
+            worker_private->connected,
+            worker_private->disconnected,
+            worker_private->max_concurrent,
+            worker_private->receptions,
+            worker_private->sends
+    );
+
+    worker_private->running = 0;
+}
+
+void *socket_listen_main_static_threaded_worker(void *ptr) {
+    worker_private = (struct web_server_static_threaded_worker *)ptr;
+    worker_private->running = 1;
+
+    netdata_thread_cleanup_push(socket_listen_main_static_threaded_worker_cleanup, ptr);
+
+            poll_events(&api_sockets
+                        , web_server_add_callback
+                        , web_server_del_callback
+                        , web_server_rcv_callback
+                        , web_server_snd_callback
+                        , web_server_tmr_callback
+                        , web_allow_connections_from
+                        , NULL
+                        , web_client_first_request_timeout
+                        , web_client_timeout
+                        , default_rrd_update_every * 1000 // timer_milliseconds
+                        , ptr // timer_data
+                        , worker_private->max_sockets
+            );
+
+    netdata_thread_cleanup_pop(1);
+    return NULL;
+}
+
+
+// ----------------------------------------------------------------------------
+// web server main thread - also becomes a worker
+
+static void socket_listen_main_static_threaded_cleanup(void *ptr) {
+    struct netdata_static_thread *static_thread = (struct netdata_static_thread *)ptr;
+    static_thread->enabled = NETDATA_MAIN_THREAD_EXITING;
+
+    int i, found = 0;
+    usec_t max = 2 * USEC_PER_SEC, step = 50000;
+
+    // we start from 1, - 0 is self
+    for(i = 1; i < static_threaded_workers_count; i++) {
+        if(static_workers_private_data[i].running) {
+            found++;
+            info("stopping worker %d", i + 1);
+            netdata_thread_cancel(static_workers_private_data[i].thread);
+        }
+        else
+            info("found stopped worker %d", i + 1);
+    }
+
+    while(found && max > 0) {
+        max -= step;
+        info("Waiting %d static web threads to finish...", found);
+        sleep_usec(step);
+        found = 0;
+
+        // we start from 1, - 0 is self
+        for(i = 1; i < static_threaded_workers_count; i++) {
+            if (static_workers_private_data[i].running)
+                found++;
+        }
+    }
+
+    if(found)
+        error("%d static web threads are taking too long to finish. Giving up.", found);
+
+    info("closing all web server sockets...");
+    listen_sockets_close(&api_sockets);
+
+    info("all static web threads stopped.");
+    static_thread->enabled = NETDATA_MAIN_THREAD_EXITED;
+}
+
+void *socket_listen_main_static_threaded(void *ptr) {
+    netdata_thread_cleanup_push(socket_listen_main_static_threaded_cleanup, ptr);
+            web_server_mode = WEB_SERVER_MODE_STATIC_THREADED;
+
+            if(!api_sockets.opened)
+                fatal("LISTENER: no listen sockets available.");
+
+            // 6 threads is the optimal value
+            // since 6 are the parallel connections browsers will do
+            // so, if the machine has more CPUs, avoid using resources unnecessarily
+            int def_thread_count = (processors > 6)?6:processors;
+
+            if (!strcmp(config_get(CONFIG_SECTION_WEB, "mode", ""),"single-threaded")) {
+                info("Running web server with one thread, because mode is single-threaded");
+                config_set(CONFIG_SECTION_WEB, "mode", "static-threaded");
+                def_thread_count = 1;
+            }
+            static_threaded_workers_count = config_get_number(CONFIG_SECTION_WEB, "web server threads", def_thread_count);
+
+            if(static_threaded_workers_count < 1) static_threaded_workers_count = 1;
+
+            size_t max_sockets = (size_t)config_get_number(CONFIG_SECTION_WEB, "web server max sockets", (long long int)(rlimit_nofile.rlim_cur / 2));
+
+            static_workers_private_data = callocz((size_t)static_threaded_workers_count, sizeof(struct web_server_static_threaded_worker));
+
+            web_server_is_multithreaded = (static_threaded_workers_count > 1);
+
+            int i;
+            for(i = 1; i < static_threaded_workers_count; i++) {
+                static_workers_private_data[i].id = i;
+                static_workers_private_data[i].max_sockets = max_sockets / static_threaded_workers_count;
+
+                char tag[50 + 1];
+                snprintfz(tag, 50, "WEB_SERVER[static%d]", i+1);
+
+                info("starting worker %d", i+1);
+                netdata_thread_create(&static_workers_private_data[i].thread, tag, NETDATA_THREAD_OPTION_DEFAULT, socket_listen_main_static_threaded_worker, (void *)&static_workers_private_data[i]);
+            }
+
+            // and the main one
+            static_workers_private_data[0].max_sockets = max_sockets / static_threaded_workers_count;
+            socket_listen_main_static_threaded_worker((void *)&static_workers_private_data[0]);
+
+    netdata_thread_cleanup_pop(1);
+    return NULL;
+}
diff --git a/web/server/static/static-threaded.h b/web/server/static/static-threaded.h
new file mode 100644
index 0000000..5f4862e
--- /dev/null
+++ b/web/server/static/static-threaded.h
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef NETDATA_WEB_SERVER_STATIC_THREADED_H
+#define NETDATA_WEB_SERVER_STATIC_THREADED_H
+
+#include "web/server/web_server.h"
+
+extern void *socket_listen_main_static_threaded(void *ptr);
+
+#endif //NETDATA_WEB_SERVER_STATIC_THREADED_H
diff --git a/web/server/web_client.c b/web/server/web_client.c
new file mode 100644
index 0000000..4e34ae3
--- /dev/null
+++ b/web/server/web_client.c
@@ -0,0 +1,1691 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "web_client.h"
+
+// this is an async I/O implementation of the web server request parser
+// it is used by all netdata web servers
+
+int respect_web_browser_do_not_track_policy = 0;
+char *web_x_frame_options = NULL;
+
+#ifdef NETDATA_WITH_ZLIB
+int web_enable_gzip = 1, web_gzip_level = 3, web_gzip_strategy = Z_DEFAULT_STRATEGY;
+#endif /* NETDATA_WITH_ZLIB */
+
+inline int web_client_permission_denied(struct web_client *w) {
+    w->response.data->contenttype = CT_TEXT_PLAIN;
+    buffer_flush(w->response.data);
+    buffer_strcat(w->response.data, "You are not allowed to access this resource.");
+    w->response.code = 403;
+    return 403;
+}
+
+static inline int web_client_crock_socket(struct web_client *w) {
+#ifdef TCP_CORK
+    if(likely(web_client_is_corkable(w) && !w->tcp_cork && w->ofd != -1)) {
+        w->tcp_cork = 1;
+        if(unlikely(setsockopt(w->ofd, IPPROTO_TCP, TCP_CORK, (char *) &w->tcp_cork, sizeof(int)) != 0)) {
+            error("%llu: failed to enable TCP_CORK on socket.", w->id);
+
+            w->tcp_cork = 0;
+            return -1;
+        }
+    }
+#else
+    (void)w;
+#endif /* TCP_CORK */
+
+    return 0;
+}
+
+static inline int web_client_uncrock_socket(struct web_client *w) {
+#ifdef TCP_CORK
+    if(likely(w->tcp_cork && w->ofd != -1)) {
+        w->tcp_cork = 0;
+        if(unlikely(setsockopt(w->ofd, IPPROTO_TCP, TCP_CORK, (char *) &w->tcp_cork, sizeof(int)) != 0)) {
+            error("%llu: failed to disable TCP_CORK on socket.", w->id);
+            w->tcp_cork = 1;
+            return -1;
+        }
+    }
+#else
+    (void)w;
+#endif /* TCP_CORK */
+
+    return 0;
+}
+
+static inline char *strip_control_characters(char *url) {
+    char *s = url;
+    if(!s) return "";
+
+    if(iscntrl(*s)) *s = ' ';
+    while(*++s) {
+        if(iscntrl(*s)) *s = ' ';
+    }
+
+    return url;
+}
+
+void web_client_request_done(struct web_client *w) {
+    web_client_uncrock_socket(w);
+
+    debug(D_WEB_CLIENT, "%llu: Resetting client.", w->id);
+
+    if(likely(w->last_url[0])) {
+        struct timeval tv;
+        now_realtime_timeval(&tv);
+
+        size_t size = (w->mode == WEB_CLIENT_MODE_FILECOPY)?w->response.rlen:w->response.data->len;
+        size_t sent = size;
+#ifdef NETDATA_WITH_ZLIB
+        if(likely(w->response.zoutput)) sent = (size_t)w->response.zstream.total_out;
+#endif
+
+        // --------------------------------------------------------------------
+        // global statistics
+
+        finished_web_request_statistics(dt_usec(&tv, &w->tv_in),
+                                        w->stats_received_bytes,
+                                        w->stats_sent_bytes,
+                                        size,
+                                        sent);
+
+        w->stats_received_bytes = 0;
+        w->stats_sent_bytes = 0;
+
+
+        // --------------------------------------------------------------------
+
+        const char *mode;
+        switch(w->mode) {
+            case WEB_CLIENT_MODE_FILECOPY:
+                mode = "FILECOPY";
+                break;
+
+            case WEB_CLIENT_MODE_OPTIONS:
+                mode = "OPTIONS";
+                break;
+
+            case WEB_CLIENT_MODE_STREAM:
+                mode = "STREAM";
+                break;
+
+            case WEB_CLIENT_MODE_NORMAL:
+                mode = "DATA";
+                break;
+
+            default:
+                mode = "UNKNOWN";
+                break;
+        }
+
+        // access log
+        log_access("%llu: %d '[%s]:%s' '%s' (sent/all = %zu/%zu bytes %0.0f%%, prep/sent/total = %0.2f/%0.2f/%0.2f ms) %d '%s'",
+                   w->id
+                   , gettid()
+                   , w->client_ip
+                   , w->client_port
+                   , mode
+                   , sent
+                   , size
+                   , -((size > 0) ? ((size - sent) / (double) size * 100.0) : 0.0)
+                   , dt_usec(&w->tv_ready, &w->tv_in) / 1000.0
+                   , dt_usec(&tv, &w->tv_ready) / 1000.0
+                   , dt_usec(&tv, &w->tv_in) / 1000.0
+                   , w->response.code
+                   , strip_control_characters(w->last_url)
+        );
+    }
+
+    if(unlikely(w->mode == WEB_CLIENT_MODE_FILECOPY)) {
+        if(w->ifd != w->ofd) {
+            debug(D_WEB_CLIENT, "%llu: Closing filecopy input file descriptor %d.", w->id, w->ifd);
+
+            if(web_server_mode != WEB_SERVER_MODE_STATIC_THREADED) {
+                if (w->ifd != -1) close(w->ifd);
+            }
+
+            w->ifd = w->ofd;
+        }
+    }
+
+    w->last_url[0] = '\0';
+    w->cookie1[0] = '\0';
+    w->cookie2[0] = '\0';
+    w->origin[0] = '*';
+    w->origin[1] = '\0';
+
+    freez(w->user_agent); w->user_agent = NULL;
+    if (w->auth_bearer_token) {
+        freez(w->auth_bearer_token);
+        w->auth_bearer_token = NULL;
+    }
+
+    w->mode = WEB_CLIENT_MODE_NORMAL;
+
+    w->tcp_cork = 0;
+    web_client_disable_donottrack(w);
+    web_client_disable_tracking_required(w);
+    web_client_disable_keepalive(w);
+    w->decoded_url[0] = '\0';
+
+    buffer_reset(w->response.header_output);
+    buffer_reset(w->response.header);
+    buffer_reset(w->response.data);
+    w->response.rlen = 0;
+    w->response.sent = 0;
+    w->response.code = 0;
+
+    w->header_parse_tries = 0;
+    w->header_parse_last_size = 0;
+
+    web_client_enable_wait_receive(w);
+    web_client_disable_wait_send(w);
+
+    w->response.zoutput = 0;
+
+    // if we had enabled compression, release it
+#ifdef NETDATA_WITH_ZLIB
+    if(w->response.zinitialized) {
+        debug(D_DEFLATE, "%llu: Freeing compression resources.", w->id);
+        deflateEnd(&w->response.zstream);
+        w->response.zsent = 0;
+        w->response.zhave = 0;
+        w->response.zstream.avail_in = 0;
+        w->response.zstream.avail_out = 0;
+        w->response.zstream.total_in = 0;
+        w->response.zstream.total_out = 0;
+        w->response.zinitialized = 0;
+    }
+#endif // NETDATA_WITH_ZLIB
+}
+
+uid_t web_files_uid(void) {
+    static char *web_owner = NULL;
+    static uid_t owner_uid = 0;
+
+    if(unlikely(!web_owner)) {
+        // getpwuid() is not thread safe,
+        // but we have called this function once
+        // while single threaded
+        struct passwd *pw = getpwuid(geteuid());
+        web_owner = config_get(CONFIG_SECTION_WEB, "web files owner", (pw)?(pw->pw_name?pw->pw_name:""):"");
+        if(!web_owner || !*web_owner)
+            owner_uid = geteuid();
+        else {
+            // getpwnam() is not thread safe,
+            // but we have called this function once
+            // while single threaded
+            pw = getpwnam(web_owner);
+            if(!pw) {
+                error("User '%s' is not present. Ignoring option.", web_owner);
+                owner_uid = geteuid();
+            }
+            else {
+                debug(D_WEB_CLIENT, "Web files owner set to %s.", web_owner);
+                owner_uid = pw->pw_uid;
+            }
+        }
+    }
+
+    return(owner_uid);
+}
+
+gid_t web_files_gid(void) {
+    static char *web_group = NULL;
+    static gid_t owner_gid = 0;
+
+    if(unlikely(!web_group)) {
+        // getgrgid() is not thread safe,
+        // but we have called this function once
+        // while single threaded
+        struct group *gr = getgrgid(getegid());
+        web_group = config_get(CONFIG_SECTION_WEB, "web files group", (gr)?(gr->gr_name?gr->gr_name:""):"");
+        if(!web_group || !*web_group)
+            owner_gid = getegid();
+        else {
+            // getgrnam() is not thread safe,
+            // but we have called this function once
+            // while single threaded
+            gr = getgrnam(web_group);
+            if(!gr) {
+                error("Group '%s' is not present. Ignoring option.", web_group);
+                owner_gid = getegid();
+            }
+            else {
+                debug(D_WEB_CLIENT, "Web files group set to %s.", web_group);
+                owner_gid = gr->gr_gid;
+            }
+        }
+    }
+
+    return(owner_gid);
+}
+
+static struct {
+    const char *extension;
+    uint32_t hash;
+    uint8_t contenttype;
+} mime_types[] = {
+        {  "html" , 0    , CT_TEXT_HTML}
+        , {"js"   , 0    , CT_APPLICATION_X_JAVASCRIPT}
+        , {"css"  , 0    , CT_TEXT_CSS}
+        , {"xml"  , 0    , CT_TEXT_XML}
+        , {"xsl"  , 0    , CT_TEXT_XSL}
+        , {"txt"  , 0    , CT_TEXT_PLAIN}
+        , {"svg"  , 0    , CT_IMAGE_SVG_XML}
+        , {"ttf"  , 0    , CT_APPLICATION_X_FONT_TRUETYPE}
+        , {"otf"  , 0    , CT_APPLICATION_X_FONT_OPENTYPE}
+        , {"woff2", 0    , CT_APPLICATION_FONT_WOFF2}
+        , {"woff" , 0    , CT_APPLICATION_FONT_WOFF}
+        , {"eot"  , 0    , CT_APPLICATION_VND_MS_FONTOBJ}
+        , {"png"  , 0    , CT_IMAGE_PNG}
+        , {"jpg"  , 0    , CT_IMAGE_JPG}
+        , {"jpeg" , 0    , CT_IMAGE_JPG}
+        , {"gif"  , 0    , CT_IMAGE_GIF}
+        , {"bmp"  , 0    , CT_IMAGE_BMP}
+        , {"ico"  , 0    , CT_IMAGE_XICON}
+        , {"icns" , 0    , CT_IMAGE_ICNS}
+        , {       NULL, 0, 0}
+};
+
+static inline uint8_t contenttype_for_filename(const char *filename) {
+    // info("checking filename '%s'", filename);
+
+    static int initialized = 0;
+    int i;
+
+    if(unlikely(!initialized)) {
+        for (i = 0; mime_types[i].extension; i++)
+            mime_types[i].hash = simple_hash(mime_types[i].extension);
+
+        initialized = 1;
+    }
+
+    const char *s = filename, *last_dot = NULL;
+
+    // find the last dot
+    while(*s) {
+        if(unlikely(*s == '.')) last_dot = s;
+        s++;
+    }
+
+    if(unlikely(!last_dot || !*last_dot || !last_dot[1])) {
+        // info("no extension for filename '%s'", filename);
+        return CT_APPLICATION_OCTET_STREAM;
+    }
+    last_dot++;
+
+    // info("extension for filename '%s' is '%s'", filename, last_dot);
+
+    uint32_t hash = simple_hash(last_dot);
+    for(i = 0; mime_types[i].extension ; i++) {
+        if(unlikely(hash == mime_types[i].hash && !strcmp(last_dot, mime_types[i].extension))) {
+            // info("matched extension for filename '%s': '%s'", filename, last_dot);
+            return mime_types[i].contenttype;
+        }
+    }
+
+    // info("not matched extension for filename '%s': '%s'", filename, last_dot);
+    return CT_APPLICATION_OCTET_STREAM;
+}
+
+static inline int access_to_file_is_not_permitted(struct web_client *w, const char *filename) {
+    w->response.data->contenttype = CT_TEXT_HTML;
+    buffer_strcat(w->response.data, "Access to file is not permitted: ");
+    buffer_strcat_htmlescape(w->response.data, filename);
+    return 403;
+}
+
+int mysendfile(struct web_client *w, char *filename) {
+    debug(D_WEB_CLIENT, "%llu: Looking for file '%s/%s'", w->id, netdata_configured_web_dir, filename);
+
+    if(!web_client_can_access_dashboard(w))
+        return web_client_permission_denied(w);
+
+    // skip leading slashes
+    while (*filename == '/') filename++;
+
+    // if the filename contains "strange" characters, refuse to serve it
+    char *s;
+    for(s = filename; *s ;s++) {
+        if( !isalnum(*s) && *s != '/' && *s != '.' && *s != '-' && *s != '_') {
+            debug(D_WEB_CLIENT_ACCESS, "%llu: File '%s' is not acceptable.", w->id, filename);
+            w->response.data->contenttype = CT_TEXT_HTML;
+            buffer_sprintf(w->response.data, "Filename contains invalid characters: ");
+            buffer_strcat_htmlescape(w->response.data, filename);
+            return 400;
+        }
+    }
+
+    // if the filename contains a .. refuse to serve it
+    if(strstr(filename, "..") != 0) {
+        debug(D_WEB_CLIENT_ACCESS, "%llu: File '%s' is not acceptable.", w->id, filename);
+        w->response.data->contenttype = CT_TEXT_HTML;
+        buffer_strcat(w->response.data, "Relative filenames are not supported: ");
+        buffer_strcat_htmlescape(w->response.data, filename);
+        return 400;
+    }
+
+    // find the physical file on disk
+    char webfilename[FILENAME_MAX + 1];
+    snprintfz(webfilename, FILENAME_MAX, "%s/%s", netdata_configured_web_dir, filename);
+
+    struct stat statbuf;
+    int done = 0;
+    while(!done) {
+        // check if the file exists
+        if (lstat(webfilename, &statbuf) != 0) {
+            debug(D_WEB_CLIENT_ACCESS, "%llu: File '%s' is not found.", w->id, webfilename);
+            w->response.data->contenttype = CT_TEXT_HTML;
+            buffer_strcat(w->response.data, "File does not exist, or is not accessible: ");
+            buffer_strcat_htmlescape(w->response.data, webfilename);
+            return 404;
+        }
+
+        if ((statbuf.st_mode & S_IFMT) == S_IFDIR) {
+            snprintfz(webfilename, FILENAME_MAX, "%s/%s/index.html", netdata_configured_web_dir, filename);
+            continue;
+        }
+
+        if ((statbuf.st_mode & S_IFMT) != S_IFREG) {
+            error("%llu: File '%s' is not a regular file. Access Denied.", w->id, webfilename);
+            return access_to_file_is_not_permitted(w, webfilename);
+        }
+
+        // check if the file is owned by expected user
+        if (statbuf.st_uid != web_files_uid()) {
+            error("%llu: File '%s' is owned by user %u (expected user %u). Access Denied.", w->id, webfilename, statbuf.st_uid, web_files_uid());
+            return access_to_file_is_not_permitted(w, webfilename);
+        }
+
+        // check if the file is owned by expected group
+        if (statbuf.st_gid != web_files_gid()) {
+            error("%llu: File '%s' is owned by group %u (expected group %u). Access Denied.", w->id, webfilename, statbuf.st_gid, web_files_gid());
+            return access_to_file_is_not_permitted(w, webfilename);
+        }
+
+        done = 1;
+    }
+
+    // open the file
+    w->ifd = open(webfilename, O_NONBLOCK, O_RDONLY);
+    if(w->ifd == -1) {
+        w->ifd = w->ofd;
+
+        if(errno == EBUSY || errno == EAGAIN) {
+            error("%llu: File '%s' is busy, sending 307 Moved Temporarily to force retry.", w->id, webfilename);
+            w->response.data->contenttype = CT_TEXT_HTML;
+            buffer_sprintf(w->response.header, "Location: /%s\r\n", filename);
+            buffer_strcat(w->response.data, "File is currently busy, please try again later: ");
+            buffer_strcat_htmlescape(w->response.data, webfilename);
+            return 307;
+        }
+        else {
+            error("%llu: Cannot open file '%s'.", w->id, webfilename);
+            w->response.data->contenttype = CT_TEXT_HTML;
+            buffer_strcat(w->response.data, "Cannot open file: ");
+            buffer_strcat_htmlescape(w->response.data, webfilename);
+            return 404;
+        }
+    }
+
+    sock_setnonblock(w->ifd);
+
+    w->response.data->contenttype = contenttype_for_filename(webfilename);
+    debug(D_WEB_CLIENT_ACCESS, "%llu: Sending file '%s' (%ld bytes, ifd %d, ofd %d).", w->id, webfilename, statbuf.st_size, w->ifd, w->ofd);
+
+    w->mode = WEB_CLIENT_MODE_FILECOPY;
+    web_client_enable_wait_receive(w);
+    web_client_disable_wait_send(w);
+    buffer_flush(w->response.data);
+    buffer_need_bytes(w->response.data, (size_t)statbuf.st_size);
+    w->response.rlen = (size_t)statbuf.st_size;
+#ifdef __APPLE__
+    w->response.data->date = statbuf.st_mtimespec.tv_sec;
+#else
+    w->response.data->date = statbuf.st_mtim.tv_sec;
+#endif /* __APPLE__ */
+    buffer_cacheable(w->response.data);
+
+    return 200;
+}
+
+
+#ifdef NETDATA_WITH_ZLIB
+void web_client_enable_deflate(struct web_client *w, int gzip) {
+    if(unlikely(w->response.zinitialized)) {
+        debug(D_DEFLATE, "%llu: Compression has already be initialized for this client.", w->id);
+        return;
+    }
+
+    if(unlikely(w->response.sent)) {
+        error("%llu: Cannot enable compression in the middle of a conversation.", w->id);
+        return;
+    }
+
+    w->response.zstream.zalloc = Z_NULL;
+    w->response.zstream.zfree = Z_NULL;
+    w->response.zstream.opaque = Z_NULL;
+
+    w->response.zstream.next_in = (Bytef *)w->response.data->buffer;
+    w->response.zstream.avail_in = 0;
+    w->response.zstream.total_in = 0;
+
+    w->response.zstream.next_out = w->response.zbuffer;
+    w->response.zstream.avail_out = 0;
+    w->response.zstream.total_out = 0;
+
+    w->response.zstream.zalloc = Z_NULL;
+    w->response.zstream.zfree = Z_NULL;
+    w->response.zstream.opaque = Z_NULL;
+
+//  if(deflateInit(&w->response.zstream, Z_DEFAULT_COMPRESSION) != Z_OK) {
+//      error("%llu: Failed to initialize zlib. Proceeding without compression.", w->id);
+//      return;
+//  }
+
+    // Select GZIP compression: windowbits = 15 + 16 = 31
+    if(deflateInit2(&w->response.zstream, web_gzip_level, Z_DEFLATED, 15 + ((gzip)?16:0), 8, web_gzip_strategy) != Z_OK) {
+        error("%llu: Failed to initialize zlib. Proceeding without compression.", w->id);
+        return;
+    }
+
+    w->response.zsent = 0;
+    w->response.zoutput = 1;
+    w->response.zinitialized = 1;
+
+    debug(D_DEFLATE, "%llu: Initialized compression.", w->id);
+}
+#endif // NETDATA_WITH_ZLIB
+
+void buffer_data_options2string(BUFFER *wb, uint32_t options) {
+    int count = 0;
+
+    if(options & RRDR_OPTION_NONZERO) {
+        if(count++) buffer_strcat(wb, " ");
+        buffer_strcat(wb, "nonzero");
+    }
+
+    if(options & RRDR_OPTION_REVERSED) {
+        if(count++) buffer_strcat(wb, " ");
+        buffer_strcat(wb, "flip");
+    }
+
+    if(options & RRDR_OPTION_JSON_WRAP) {
+        if(count++) buffer_strcat(wb, " ");
+        buffer_strcat(wb, "jsonwrap");
+    }
+
+    if(options & RRDR_OPTION_MIN2MAX) {
+        if(count++) buffer_strcat(wb, " ");
+        buffer_strcat(wb, "min2max");
+    }
+
+    if(options & RRDR_OPTION_MILLISECONDS) {
+        if(count++) buffer_strcat(wb, " ");
+        buffer_strcat(wb, "ms");
+    }
+
+    if(options & RRDR_OPTION_ABSOLUTE) {
+        if(count++) buffer_strcat(wb, " ");
+        buffer_strcat(wb, "absolute");
+    }
+
+    if(options & RRDR_OPTION_SECONDS) {
+        if(count++) buffer_strcat(wb, " ");
+        buffer_strcat(wb, "seconds");
+    }
+
+    if(options & RRDR_OPTION_NULL2ZERO) {
+        if(count++) buffer_strcat(wb, " ");
+        buffer_strcat(wb, "null2zero");
+    }
+
+    if(options & RRDR_OPTION_OBJECTSROWS) {
+        if(count++) buffer_strcat(wb, " ");
+        buffer_strcat(wb, "objectrows");
+    }
+
+    if(options & RRDR_OPTION_GOOGLE_JSON) {
+        if(count++) buffer_strcat(wb, " ");
+        buffer_strcat(wb, "google_json");
+    }
+
+    if(options & RRDR_OPTION_PERCENTAGE) {
+        if(count++) buffer_strcat(wb, " ");
+        buffer_strcat(wb, "percentage");
+    }
+
+    if(options & RRDR_OPTION_NOT_ALIGNED) {
+        if(count++) buffer_strcat(wb, " ");
+        buffer_strcat(wb, "unaligned");
+    }
+}
+
+static inline int check_host_and_call(RRDHOST *host, struct web_client *w, char *url, int (*func)(RRDHOST *, struct web_client *, char *)) {
+    if(unlikely(host->rrd_memory_mode == RRD_MEMORY_MODE_NONE)) {
+        buffer_flush(w->response.data);
+        buffer_strcat(w->response.data, "This host does not maintain a database");
+        return 400;
+    }
+
+    return func(host, w, url);
+}
+
+static inline int check_host_and_dashboard_acl_and_call(RRDHOST *host, struct web_client *w, char *url, int (*func)(RRDHOST *, struct web_client *, char *)) {
+    if(!web_client_can_access_dashboard(w))
+        return web_client_permission_denied(w);
+
+    return check_host_and_call(host, w, url, func);
+}
+
+static inline int check_host_and_mgmt_acl_and_call(RRDHOST *host, struct web_client *w, char *url, int (*func)(RRDHOST *, struct web_client *, char *)) {
+    if(!web_client_can_access_mgmt(w))
+        return web_client_permission_denied(w);
+
+    return check_host_and_call(host, w, url, func);
+}
+
+int web_client_api_request(RRDHOST *host, struct web_client *w, char *url)
+{
+    // get the api version
+    char *tok = mystrsep(&url, "/");
+    if(tok && *tok) {
+        debug(D_WEB_CLIENT, "%llu: Searching for API version '%s'.", w->id, tok);
+        if(strcmp(tok, "v1") == 0)
+            return web_client_api_request_v1(host, w, url);
+        else {
+            buffer_flush(w->response.data);
+            w->response.data->contenttype = CT_TEXT_HTML;
+            buffer_strcat(w->response.data, "Unsupported API version: ");
+            buffer_strcat_htmlescape(w->response.data, tok);
+            return 404;
+        }
+    }
+    else {
+        buffer_flush(w->response.data);
+        buffer_sprintf(w->response.data, "Which API version?");
+        return 400;
+    }
+}
+
+const char *web_content_type_to_string(uint8_t contenttype) {
+    switch(contenttype) {
+        case CT_TEXT_HTML:
+            return "text/html; charset=utf-8";
+
+        case CT_APPLICATION_XML:
+            return "application/xml; charset=utf-8";
+
+        case CT_APPLICATION_JSON:
+            return "application/json; charset=utf-8";
+
+        case CT_APPLICATION_X_JAVASCRIPT:
+            return "application/x-javascript; charset=utf-8";
+
+        case CT_TEXT_CSS:
+            return "text/css; charset=utf-8";
+
+        case CT_TEXT_XML:
+            return "text/xml; charset=utf-8";
+
+        case CT_TEXT_XSL:
+            return "text/xsl; charset=utf-8";
+
+        case CT_APPLICATION_OCTET_STREAM:
+            return "application/octet-stream";
+
+        case CT_IMAGE_SVG_XML:
+            return "image/svg+xml";
+
+        case CT_APPLICATION_X_FONT_TRUETYPE:
+            return "application/x-font-truetype";
+
+        case CT_APPLICATION_X_FONT_OPENTYPE:
+            return "application/x-font-opentype";
+
+        case CT_APPLICATION_FONT_WOFF:
+            return "application/font-woff";
+
+        case CT_APPLICATION_FONT_WOFF2:
+            return "application/font-woff2";
+
+        case CT_APPLICATION_VND_MS_FONTOBJ:
+            return "application/vnd.ms-fontobject";
+
+        case CT_IMAGE_PNG:
+            return "image/png";
+
+        case CT_IMAGE_JPG:
+            return "image/jpeg";
+
+        case CT_IMAGE_GIF:
+            return "image/gif";
+
+        case CT_IMAGE_XICON:
+            return "image/x-icon";
+
+        case CT_IMAGE_BMP:
+            return "image/bmp";
+
+        case CT_IMAGE_ICNS:
+            return "image/icns";
+
+        case CT_PROMETHEUS:
+            return "text/plain; version=0.0.4";
+
+        default:
+        case CT_TEXT_PLAIN:
+            return "text/plain; charset=utf-8";
+    }
+}
+
+
+const char *web_response_code_to_string(int code) {
+    switch(code) {
+        case 200:
+            return "OK";
+
+        case 307:
+            return "Temporary Redirect";
+
+        case 400:
+            return "Bad Request";
+
+        case 403:
+            return "Forbidden";
+
+        case 404:
+            return "Not Found";
+
+        case 412:
+            return "Preconditions Failed";
+
+        default:
+            if(code >= 100 && code < 200)
+                return "Informational";
+
+            if(code >= 200 && code < 300)
+                return "Successful";
+
+            if(code >= 300 && code < 400)
+                return "Redirection";
+
+            if(code >= 400 && code < 500)
+                return "Bad Request";
+
+            if(code >= 500 && code < 600)
+                return "Server Error";
+
+            return "Undefined Error";
+    }
+}
+
+static inline char *http_header_parse(struct web_client *w, char *s, int parse_useragent) {
+    static uint32_t hash_origin = 0, hash_connection = 0, hash_accept_encoding = 0, hash_donottrack = 0, hash_useragent = 0, hash_authorization = 0;
+
+    if(unlikely(!hash_origin)) {
+        hash_origin = simple_uhash("Origin");
+        hash_connection = simple_uhash("Connection");
+        hash_accept_encoding = simple_uhash("Accept-Encoding");
+        hash_donottrack = simple_uhash("DNT");
+        hash_useragent = simple_uhash("User-Agent");
+        hash_authorization = simple_uhash("X-Auth-Token");
+    }
+
+    char *e = s;
+
+    // find the :
+    while(*e && *e != ':') e++;
+    if(!*e) return e;
+
+    // get the name
+    *e = '\0';
+
+    // find the value
+    char *v = e + 1, *ve;
+
+    // skip leading spaces from value
+    while(*v == ' ') v++;
+    ve = v;
+
+    // find the \r
+    while(*ve && *ve != '\r') ve++;
+    if(!*ve || ve[1] != '\n') {
+        *e = ':';
+        return ve;
+    }
+
+    // terminate the value
+    *ve = '\0';
+
+    // fprintf(stderr, "HEADER: '%s' = '%s'\n", s, v);
+    uint32_t hash = simple_uhash(s);
+
+    if(hash == hash_origin && !strcasecmp(s, "Origin"))
+        strncpyz(w->origin, v, NETDATA_WEB_REQUEST_ORIGIN_HEADER_SIZE);
+
+    else if(hash == hash_connection && !strcasecmp(s, "Connection")) {
+        if(strcasestr(v, "keep-alive"))
+            web_client_enable_keepalive(w);
+    }
+    else if(respect_web_browser_do_not_track_policy && hash == hash_donottrack && !strcasecmp(s, "DNT")) {
+        if(*v == '0') web_client_disable_donottrack(w);
+        else if(*v == '1') web_client_enable_donottrack(w);
+    }
+    else if(parse_useragent && hash == hash_useragent && !strcasecmp(s, "User-Agent")) {
+        w->user_agent = strdupz(v);
+    } else if(hash == hash_authorization&& !strcasecmp(s, "X-Auth-Token")) {
+        w->auth_bearer_token = strdupz(v);
+    }
+#ifdef NETDATA_WITH_ZLIB
+    else if(hash == hash_accept_encoding && !strcasecmp(s, "Accept-Encoding")) {
+        if(web_enable_gzip) {
+            if(strcasestr(v, "gzip"))
+                web_client_enable_deflate(w, 1);
+            //
+            // does not seem to work
+            // else if(strcasestr(v, "deflate"))
+            //  web_client_enable_deflate(w, 0);
+        }
+    }
+#endif /* NETDATA_WITH_ZLIB */
+
+    *e = ':';
+    *ve = '\r';
+    return ve;
+}
+
+// http_request_validate()
+// returns:
+// = 0 : all good, process the request
+// > 0 : request is not supported
+// < 0 : request is incomplete - wait for more data
+
+typedef enum {
+    HTTP_VALIDATION_OK,
+    HTTP_VALIDATION_NOT_SUPPORTED,
+    HTTP_VALIDATION_INCOMPLETE
+} HTTP_VALIDATION;
+
+static inline HTTP_VALIDATION http_request_validate(struct web_client *w) {
+    char *s = (char *)buffer_tostring(w->response.data), *encoded_url = NULL;
+
+    size_t last_pos = w->header_parse_last_size;
+    if(last_pos > 4) last_pos -= 4; // allow searching for \r\n\r\n
+    else last_pos = 0;
+
+    w->header_parse_tries++;
+    w->header_parse_last_size = buffer_strlen(w->response.data);
+
+    if(w->header_parse_tries > 1) {
+        if(w->header_parse_last_size < last_pos)
+            last_pos = 0;
+
+        if(strstr(&s[last_pos], "\r\n\r\n") == NULL) {
+            if(w->header_parse_tries > 10) {
+                info("Disabling slow client after %zu attempts to read the request (%zu bytes received)", w->header_parse_tries, buffer_strlen(w->response.data));
+                w->header_parse_tries = 0;
+                w->header_parse_last_size = 0;
+                web_client_disable_wait_receive(w);
+                return HTTP_VALIDATION_NOT_SUPPORTED;
+            }
+
+            return HTTP_VALIDATION_INCOMPLETE;
+        }
+    }
+
+    // is is a valid request?
+    if(!strncmp(s, "GET ", 4)) {
+        encoded_url = s = &s[4];
+        w->mode = WEB_CLIENT_MODE_NORMAL;
+    }
+    else if(!strncmp(s, "OPTIONS ", 8)) {
+        encoded_url = s = &s[8];
+        w->mode = WEB_CLIENT_MODE_OPTIONS;
+    }
+    else if(!strncmp(s, "STREAM ", 7)) {
+        encoded_url = s = &s[7];
+        w->mode = WEB_CLIENT_MODE_STREAM;
+    }
+    else {
+        w->header_parse_tries = 0;
+        w->header_parse_last_size = 0;
+        web_client_disable_wait_receive(w);
+        return HTTP_VALIDATION_NOT_SUPPORTED;
+    }
+
+    // find the SPACE + "HTTP/"
+    while(*s) {
+        // find the next space
+        while (*s && *s != ' ') s++;
+
+        // is it SPACE + "HTTP/" ?
+        if(*s && !strncmp(s, " HTTP/", 6)) break;
+        else s++;
+    }
+
+    // incomplete requests
+    if(unlikely(!*s)) {
+        web_client_enable_wait_receive(w);
+        return HTTP_VALIDATION_INCOMPLETE;
+    }
+
+    // we have the end of encoded_url - remember it
+    char *ue = s;
+
+    // make sure we have complete request
+    // complete requests contain: \r\n\r\n
+    while(*s) {
+        // find a line feed
+        while(*s && *s++ != '\r');
+
+        // did we reach the end?
+        if(unlikely(!*s)) break;
+
+        // is it \r\n ?
+        if(likely(*s++ == '\n')) {
+
+            // is it again \r\n ? (header end)
+            if(unlikely(*s == '\r' && s[1] == '\n')) {
+                // a valid complete HTTP request found
+
+                *ue = '\0';
+                url_decode_r(w->decoded_url, encoded_url, NETDATA_WEB_REQUEST_URL_SIZE + 1);
+                *ue = ' ';
+                
+                // copy the URL - we are going to overwrite parts of it
+                // TODO -- ideally we we should avoid copying buffers around
+                strncpyz(w->last_url, w->decoded_url, NETDATA_WEB_REQUEST_URL_SIZE);
+
+                w->header_parse_tries = 0;
+                w->header_parse_last_size = 0;
+                web_client_disable_wait_receive(w);
+                return HTTP_VALIDATION_OK;
+            }
+
+            // another header line
+            s = http_header_parse(w, s,
+                    (w->mode == WEB_CLIENT_MODE_STREAM) // parse user agent
+            );
+        }
+    }
+
+    // incomplete request
+    web_client_enable_wait_receive(w);
+    return HTTP_VALIDATION_INCOMPLETE;
+}
+
+static inline void web_client_send_http_header(struct web_client *w) {
+    if(unlikely(w->response.code != 200))
+        buffer_no_cacheable(w->response.data);
+
+    // set a proper expiration date, if not already set
+    if(unlikely(!w->response.data->expires)) {
+        if(w->response.data->options & WB_CONTENT_NO_CACHEABLE)
+            w->response.data->expires = w->tv_ready.tv_sec + localhost->rrd_update_every;
+        else
+            w->response.data->expires = w->tv_ready.tv_sec + 86400;
+    }
+
+    // prepare the HTTP response header
+    debug(D_WEB_CLIENT, "%llu: Generating HTTP header with response %d.", w->id, w->response.code);
+
+    const char *content_type_string = web_content_type_to_string(w->response.data->contenttype);
+    const char *code_msg = web_response_code_to_string(w->response.code);
+
+    // prepare the last modified and expiration dates
+    char date[32], edate[32];
+    {
+        struct tm tmbuf, *tm;
+
+        tm = gmtime_r(&w->response.data->date, &tmbuf);
+        strftime(date, sizeof(date), "%a, %d %b %Y %H:%M:%S %Z", tm);
+
+        tm = gmtime_r(&w->response.data->expires, &tmbuf);
+        strftime(edate, sizeof(edate), "%a, %d %b %Y %H:%M:%S %Z", tm);
+    }
+
+    buffer_sprintf(w->response.header_output,
+            "HTTP/1.1 %d %s\r\n"
+                    "Connection: %s\r\n"
+                    "Server: NetData Embedded HTTP Server v%s\r\n"
+                    "Access-Control-Allow-Origin: %s\r\n"
+                    "Access-Control-Allow-Credentials: true\r\n"
+                    "Content-Type: %s\r\n"
+                    "Date: %s\r\n"
+                   , w->response.code, code_msg
+                   , web_client_has_keepalive(w)?"keep-alive":"close"
+                   , VERSION
+                   , w->origin
+                   , content_type_string
+                   , date
+    );
+
+    if(unlikely(web_x_frame_options))
+        buffer_sprintf(w->response.header_output, "X-Frame-Options: %s\r\n", web_x_frame_options);
+
+    if(w->cookie1[0] || w->cookie2[0]) {
+        if(w->cookie1[0]) {
+            buffer_sprintf(w->response.header_output,
+                    "Set-Cookie: %s\r\n",
+                    w->cookie1);
+        }
+
+        if(w->cookie2[0]) {
+            buffer_sprintf(w->response.header_output,
+                    "Set-Cookie: %s\r\n",
+                    w->cookie2);
+        }
+
+        if(respect_web_browser_do_not_track_policy)
+            buffer_sprintf(w->response.header_output,
+                    "Tk: T;cookies\r\n");
+    }
+    else {
+        if(respect_web_browser_do_not_track_policy) {
+            if(web_client_has_tracking_required(w))
+                buffer_sprintf(w->response.header_output,
+                        "Tk: T;cookies\r\n");
+            else
+                buffer_sprintf(w->response.header_output,
+                        "Tk: N\r\n");
+        }
+    }
+
+    if(w->mode == WEB_CLIENT_MODE_OPTIONS) {
+        buffer_strcat(w->response.header_output,
+                "Access-Control-Allow-Methods: GET, OPTIONS\r\n"
+                        "Access-Control-Allow-Headers: accept, x-requested-with, origin, content-type, cookie, pragma, cache-control\r\n"
+                        "Access-Control-Max-Age: 1209600\r\n" // 86400 * 14
+        );
+    }
+    else {
+        buffer_sprintf(w->response.header_output,
+                "Cache-Control: %s\r\n"
+                        "Expires: %s\r\n",
+                (w->response.data->options & WB_CONTENT_NO_CACHEABLE)?"no-cache":"public",
+                edate);
+    }
+
+    // copy a possibly available custom header
+    if(unlikely(buffer_strlen(w->response.header)))
+        buffer_strcat(w->response.header_output, buffer_tostring(w->response.header));
+
+    // headers related to the transfer method
+    if(likely(w->response.zoutput)) {
+        buffer_strcat(w->response.header_output,
+                "Content-Encoding: gzip\r\n"
+                        "Transfer-Encoding: chunked\r\n"
+        );
+    }
+    else {
+        if(likely((w->response.data->len || w->response.rlen))) {
+            // we know the content length, put it
+            buffer_sprintf(w->response.header_output, "Content-Length: %zu\r\n", w->response.data->len? w->response.data->len: w->response.rlen);
+        }
+        else {
+            // we don't know the content length, disable keep-alive
+            web_client_disable_keepalive(w);
+        }
+    }
+
+    // end of HTTP header
+    buffer_strcat(w->response.header_output, "\r\n");
+
+    // sent the HTTP header
+    debug(D_WEB_DATA, "%llu: Sending response HTTP header of size %zu: '%s'"
+          , w->id
+          , buffer_strlen(w->response.header_output)
+          , buffer_tostring(w->response.header_output)
+    );
+
+    web_client_crock_socket(w);
+
+    size_t count = 0;
+    ssize_t bytes;
+    while((bytes = send(w->ofd, buffer_tostring(w->response.header_output), buffer_strlen(w->response.header_output), 0)) == -1) {
+        count++;
+
+        if(count > 100 || (errno != EAGAIN && errno != EWOULDBLOCK)) {
+            error("Cannot send HTTP headers to web client.");
+            break;
+        }
+    }
+
+    if(bytes != (ssize_t) buffer_strlen(w->response.header_output)) {
+        if(bytes > 0)
+            w->stats_sent_bytes += bytes;
+
+        error("HTTP headers failed to be sent (I sent %zu bytes but the system sent %zd bytes). Closing web client."
+              , buffer_strlen(w->response.header_output)
+              , bytes);
+
+        WEB_CLIENT_IS_DEAD(w);
+        return;
+    }
+    else
+        w->stats_sent_bytes += bytes;
+}
+
+static inline int web_client_process_url(RRDHOST *host, struct web_client *w, char *url);
+
+static inline int web_client_switch_host(RRDHOST *host, struct web_client *w, char *url) {
+    static uint32_t hash_localhost = 0;
+
+    if(unlikely(!hash_localhost)) {
+        hash_localhost = simple_hash("localhost");
+    }
+
+    if(host != localhost) {
+        buffer_flush(w->response.data);
+        buffer_strcat(w->response.data, "Nesting of hosts is not allowed.");
+        return 400;
+    }
+
+    char *tok = mystrsep(&url, "/");
+    if(tok && *tok) {
+        debug(D_WEB_CLIENT, "%llu: Searching for host with name '%s'.", w->id, tok);
+
+        // copy the URL, we need it to serve files
+        w->last_url[0] = '/';
+        if(url && *url) strncpyz(&w->last_url[1], url, NETDATA_WEB_REQUEST_URL_SIZE - 1);
+        else w->last_url[1] = '\0';
+
+        uint32_t hash = simple_hash(tok);
+
+        host = rrdhost_find_by_hostname(tok, hash);
+        if(!host) host = rrdhost_find_by_guid(tok, hash);
+
+        if(host) return web_client_process_url(host, w, url);
+    }
+
+    buffer_flush(w->response.data);
+    w->response.data->contenttype = CT_TEXT_HTML;
+    buffer_strcat(w->response.data, "This netdata does not maintain a database for host: ");
+    buffer_strcat_htmlescape(w->response.data, tok?tok:"");
+    return 404;
+}
+
+static inline int web_client_process_url(RRDHOST *host, struct web_client *w, char *url) {
+    static uint32_t
+            hash_api = 0,
+            hash_netdata_conf = 0,
+            hash_host = 0;
+
+#ifdef NETDATA_INTERNAL_CHECKS
+    static uint32_t hash_exit = 0, hash_debug = 0, hash_mirror = 0;
+#endif
+
+    if(unlikely(!hash_api)) {
+        hash_api = simple_hash("api");
+        hash_netdata_conf = simple_hash("netdata.conf");
+        hash_host = simple_hash("host");
+#ifdef NETDATA_INTERNAL_CHECKS
+        hash_exit = simple_hash("exit");
+        hash_debug = simple_hash("debug");
+        hash_mirror = simple_hash("mirror");
+#endif
+    }
+
+    char *tok = mystrsep(&url, "/?");
+    if(likely(tok && *tok)) {
+        uint32_t hash = simple_hash(tok);
+        debug(D_WEB_CLIENT, "%llu: Processing command '%s'.", w->id, tok);
+
+        if(unlikely(hash == hash_api && strcmp(tok, "api") == 0)) {                           // current API
+            debug(D_WEB_CLIENT_ACCESS, "%llu: API request ...", w->id);
+            return check_host_and_call(host, w, url, web_client_api_request);
+        }
+        else if(unlikely(hash == hash_host && strcmp(tok, "host") == 0)) {                    // host switching
+            debug(D_WEB_CLIENT_ACCESS, "%llu: host switch request ...", w->id);
+            return web_client_switch_host(host, w, url);
+        }
+        else if(unlikely(hash == hash_netdata_conf && strcmp(tok, "netdata.conf") == 0)) {    // netdata.conf
+            if(unlikely(!web_client_can_access_netdataconf(w)))
+                return web_client_permission_denied(w);
+
+            debug(D_WEB_CLIENT_ACCESS, "%llu: generating netdata.conf ...", w->id);
+            w->response.data->contenttype = CT_TEXT_PLAIN;
+            buffer_flush(w->response.data);
+            config_generate(w->response.data, 0);
+            return 200;
+        }
+#ifdef NETDATA_INTERNAL_CHECKS
+        else if(unlikely(hash == hash_exit && strcmp(tok, "exit") == 0)) {
+            if(unlikely(!web_client_can_access_netdataconf(w)))
+                return web_client_permission_denied(w);
+
+            w->response.data->contenttype = CT_TEXT_PLAIN;
+            buffer_flush(w->response.data);
+
+            if(!netdata_exit)
+                buffer_strcat(w->response.data, "ok, will do...");
+            else
+                buffer_strcat(w->response.data, "I am doing it already");
+
+            error("web request to exit received.");
+            netdata_cleanup_and_exit(0);
+            return 200;
+        }
+        else if(unlikely(hash == hash_debug && strcmp(tok, "debug") == 0)) {
+            if(unlikely(!web_client_can_access_netdataconf(w)))
+                return web_client_permission_denied(w);
+
+            buffer_flush(w->response.data);
+
+            // get the name of the data to show
+            tok = mystrsep(&url, "&");
+            if(tok && *tok) {
+                debug(D_WEB_CLIENT, "%llu: Searching for RRD data with name '%s'.", w->id, tok);
+
+                // do we have such a data set?
+                RRDSET *st = rrdset_find_byname(host, tok);
+                if(!st) st = rrdset_find(host, tok);
+                if(!st) {
+                    w->response.data->contenttype = CT_TEXT_HTML;
+                    buffer_strcat(w->response.data, "Chart is not found: ");
+                    buffer_strcat_htmlescape(w->response.data, tok);
+                    debug(D_WEB_CLIENT_ACCESS, "%llu: %s is not found.", w->id, tok);
+                    return 404;
+                }
+
+                debug_flags |= D_RRD_STATS;
+
+                if(rrdset_flag_check(st, RRDSET_FLAG_DEBUG))
+                    rrdset_flag_clear(st, RRDSET_FLAG_DEBUG);
+                else
+                    rrdset_flag_set(st, RRDSET_FLAG_DEBUG);
+
+                w->response.data->contenttype = CT_TEXT_HTML;
+                buffer_sprintf(w->response.data, "Chart has now debug %s: ", rrdset_flag_check(st, RRDSET_FLAG_DEBUG)?"enabled":"disabled");
+                buffer_strcat_htmlescape(w->response.data, tok);
+                debug(D_WEB_CLIENT_ACCESS, "%llu: debug for %s is %s.", w->id, tok, rrdset_flag_check(st, RRDSET_FLAG_DEBUG)?"enabled":"disabled");
+                return 200;
+            }
+
+            buffer_flush(w->response.data);
+            buffer_strcat(w->response.data, "debug which chart?\r\n");
+            return 400;
+        }
+        else if(unlikely(hash == hash_mirror && strcmp(tok, "mirror") == 0)) {
+            if(unlikely(!web_client_can_access_netdataconf(w)))
+                return web_client_permission_denied(w);
+
+            debug(D_WEB_CLIENT_ACCESS, "%llu: Mirroring...", w->id);
+
+            // replace the zero bytes with spaces
+            buffer_char_replace(w->response.data, '\0', ' ');
+
+            // just leave the buffer as is
+            // it will be copied back to the client
+
+            return 200;
+        }
+#endif  /* NETDATA_INTERNAL_CHECKS */
+    }
+
+    char filename[FILENAME_MAX+1];
+    url = filename;
+    strncpyz(filename, w->last_url, FILENAME_MAX);
+    tok = mystrsep(&url, "?");
+    buffer_flush(w->response.data);
+    return mysendfile(w, (tok && *tok)?tok:"/");
+}
+
+void web_client_process_request(struct web_client *w) {
+
+    // start timing us
+    now_realtime_timeval(&w->tv_in);
+
+    switch(http_request_validate(w)) {
+        case HTTP_VALIDATION_OK:
+            switch(w->mode) {
+                case WEB_CLIENT_MODE_STREAM:
+                    if(unlikely(!web_client_can_access_stream(w))) {
+                        web_client_permission_denied(w);
+                        return;
+                    }
+
+                    w->response.code = rrdpush_receiver_thread_spawn(localhost, w, w->decoded_url);
+                    return;
+
+                case WEB_CLIENT_MODE_OPTIONS:
+                    if(unlikely(
+                            !web_client_can_access_dashboard(w) &&
+                            !web_client_can_access_registry(w) &&
+                            !web_client_can_access_badges(w) &&
+                            !web_client_can_access_mgmt(w) &&
+                            !web_client_can_access_netdataconf(w)
+                    )) {
+                        web_client_permission_denied(w);
+                        break;
+                    }
+
+                    w->response.data->contenttype = CT_TEXT_PLAIN;
+                    buffer_flush(w->response.data);
+                    buffer_strcat(w->response.data, "OK");
+                    w->response.code = 200;
+                    break;
+
+                case WEB_CLIENT_MODE_FILECOPY:
+                case WEB_CLIENT_MODE_NORMAL:
+                    if(unlikely(
+                            !web_client_can_access_dashboard(w) &&
+                            !web_client_can_access_registry(w) &&
+                            !web_client_can_access_badges(w) &&
+                            !web_client_can_access_mgmt(w) &&
+                            !web_client_can_access_netdataconf(w)
+                    )) {
+                        web_client_permission_denied(w);
+                        break;
+                    }
+
+                    w->response.code = web_client_process_url(localhost, w, w->decoded_url);
+                    break;
+            }
+            break;
+
+        case HTTP_VALIDATION_INCOMPLETE:
+            if(w->response.data->len > NETDATA_WEB_REQUEST_MAX_SIZE) {
+                strcpy(w->last_url, "too big request");
+
+                debug(D_WEB_CLIENT_ACCESS, "%llu: Received request is too big (%zu bytes).", w->id, w->response.data->len);
+
+                buffer_flush(w->response.data);
+                buffer_sprintf(w->response.data, "Received request is too big  (%zu bytes).\r\n", w->response.data->len);
+                w->response.code = 400;
+            }
+            else {
+                // wait for more data
+                return;
+            }
+            break;
+
+        case HTTP_VALIDATION_NOT_SUPPORTED:
+            debug(D_WEB_CLIENT_ACCESS, "%llu: Cannot understand '%s'.", w->id, w->response.data->buffer);
+
+            buffer_flush(w->response.data);
+            buffer_strcat(w->response.data, "I don't understand you...\r\n");
+            w->response.code = 400;
+            break;
+    }
+
+    // keep track of the time we done processing
+    now_realtime_timeval(&w->tv_ready);
+
+    w->response.sent = 0;
+
+    // set a proper last modified date
+    if(unlikely(!w->response.data->date))
+        w->response.data->date = w->tv_ready.tv_sec;
+
+    web_client_send_http_header(w);
+
+    // enable sending immediately if we have data
+    if(w->response.data->len) web_client_enable_wait_send(w);
+    else web_client_disable_wait_send(w);
+
+    switch(w->mode) {
+        case WEB_CLIENT_MODE_STREAM:
+            debug(D_WEB_CLIENT, "%llu: STREAM done.", w->id);
+            break;
+
+        case WEB_CLIENT_MODE_OPTIONS:
+            debug(D_WEB_CLIENT, "%llu: Done preparing the OPTIONS response. Sending data (%zu bytes) to client.", w->id, w->response.data->len);
+            break;
+
+        case WEB_CLIENT_MODE_NORMAL:
+            debug(D_WEB_CLIENT, "%llu: Done preparing the response. Sending data (%zu bytes) to client.", w->id, w->response.data->len);
+            break;
+
+        case WEB_CLIENT_MODE_FILECOPY:
+            if(w->response.rlen) {
+                debug(D_WEB_CLIENT, "%llu: Done preparing the response. Will be sending data file of %zu bytes to client.", w->id, w->response.rlen);
+                web_client_enable_wait_receive(w);
+
+                /*
+                // utilize the kernel sendfile() for copying the file to the socket.
+                // this block of code can be commented, without anything missing.
+                // when it is commented, the program will copy the data using async I/O.
+                {
+                    long len = sendfile(w->ofd, w->ifd, NULL, w->response.data->rbytes);
+                    if(len != w->response.data->rbytes)
+                        error("%llu: sendfile() should copy %ld bytes, but copied %ld. Falling back to manual copy.", w->id, w->response.data->rbytes, len);
+                    else
+                        web_client_request_done(w);
+                }
+                */
+            }
+            else
+                debug(D_WEB_CLIENT, "%llu: Done preparing the response. Will be sending an unknown amount of bytes to client.", w->id);
+            break;
+
+        default:
+            fatal("%llu: Unknown client mode %u.", w->id, w->mode);
+            break;
+    }
+}
+
+ssize_t web_client_send_chunk_header(struct web_client *w, size_t len)
+{
+    debug(D_DEFLATE, "%llu: OPEN CHUNK of %zu bytes (hex: %zx).", w->id, len, len);
+    char buf[24];
+    sprintf(buf, "%zX\r\n", len);
+    
+    ssize_t bytes = send(w->ofd, buf, strlen(buf), 0);
+    if(bytes > 0) {
+        debug(D_DEFLATE, "%llu: Sent chunk header %zd bytes.", w->id, bytes);
+        w->stats_sent_bytes += bytes;
+    }
+
+    else if(bytes == 0) {
+        debug(D_WEB_CLIENT, "%llu: Did not send chunk header to the client.", w->id);
+        WEB_CLIENT_IS_DEAD(w);
+    }
+    else {
+        debug(D_WEB_CLIENT, "%llu: Failed to send chunk header to client.", w->id);
+        WEB_CLIENT_IS_DEAD(w);
+    }
+
+    return bytes;
+}
+
+ssize_t web_client_send_chunk_close(struct web_client *w)
+{
+    //debug(D_DEFLATE, "%llu: CLOSE CHUNK.", w->id);
+
+    ssize_t bytes = send(w->ofd, "\r\n", 2, 0);
+    if(bytes > 0) {
+        debug(D_DEFLATE, "%llu: Sent chunk suffix %zd bytes.", w->id, bytes);
+        w->stats_sent_bytes += bytes;
+    }
+
+    else if(bytes == 0) {
+        debug(D_WEB_CLIENT, "%llu: Did not send chunk suffix to the client.", w->id);
+        WEB_CLIENT_IS_DEAD(w);
+    }
+    else {
+        debug(D_WEB_CLIENT, "%llu: Failed to send chunk suffix to client.", w->id);
+        WEB_CLIENT_IS_DEAD(w);
+    }
+
+    return bytes;
+}
+
+ssize_t web_client_send_chunk_finalize(struct web_client *w)
+{
+    //debug(D_DEFLATE, "%llu: FINALIZE CHUNK.", w->id);
+
+    ssize_t bytes = send(w->ofd, "\r\n0\r\n\r\n", 7, 0);
+    if(bytes > 0) {
+        debug(D_DEFLATE, "%llu: Sent chunk suffix %zd bytes.", w->id, bytes);
+        w->stats_sent_bytes += bytes;
+    }
+
+    else if(bytes == 0) {
+        debug(D_WEB_CLIENT, "%llu: Did not send chunk finalize suffix to the client.", w->id);
+        WEB_CLIENT_IS_DEAD(w);
+    }
+    else {
+        debug(D_WEB_CLIENT, "%llu: Failed to send chunk finalize suffix to client.", w->id);
+        WEB_CLIENT_IS_DEAD(w);
+    }
+
+    return bytes;
+}
+
+#ifdef NETDATA_WITH_ZLIB
+ssize_t web_client_send_deflate(struct web_client *w)
+{
+    ssize_t len = 0, t = 0;
+
+    // when using compression,
+    // w->response.sent is the amount of bytes passed through compression
+
+    debug(D_DEFLATE, "%llu: web_client_send_deflate(): w->response.data->len = %zu, w->response.sent = %zu, w->response.zhave = %zu, w->response.zsent = %zu, w->response.zstream.avail_in = %u, w->response.zstream.avail_out = %u, w->response.zstream.total_in = %lu, w->response.zstream.total_out = %lu.",
+        w->id, w->response.data->len, w->response.sent, w->response.zhave, w->response.zsent, w->response.zstream.avail_in, w->response.zstream.avail_out, w->response.zstream.total_in, w->response.zstream.total_out);
+
+    if(w->response.data->len - w->response.sent == 0 && w->response.zstream.avail_in == 0 && w->response.zhave == w->response.zsent && w->response.zstream.avail_out != 0) {
+        // there is nothing to send
+
+        debug(D_WEB_CLIENT, "%llu: Out of output data.", w->id);
+
+        // finalize the chunk
+        if(w->response.sent != 0) {
+            t = web_client_send_chunk_finalize(w);
+            if(t < 0) return t;
+        }
+
+        if(w->mode == WEB_CLIENT_MODE_FILECOPY && web_client_has_wait_receive(w) && w->response.rlen && w->response.rlen > w->response.data->len) {
+            // we have to wait, more data will come
+            debug(D_WEB_CLIENT, "%llu: Waiting for more data to become available.", w->id);
+            web_client_disable_wait_send(w);
+            return t;
+        }
+
+        if(unlikely(!web_client_has_keepalive(w))) {
+            debug(D_WEB_CLIENT, "%llu: Closing (keep-alive is not enabled). %zu bytes sent.", w->id, w->response.sent);
+            WEB_CLIENT_IS_DEAD(w);
+            return t;
+        }
+
+        // reset the client
+        web_client_request_done(w);
+        debug(D_WEB_CLIENT, "%llu: Done sending all data on socket.", w->id);
+        return t;
+    }
+
+    if(w->response.zhave == w->response.zsent) {
+        // compress more input data
+
+        // close the previous open chunk
+        if(w->response.sent != 0) {
+            t = web_client_send_chunk_close(w);
+            if(t < 0) return t;
+        }
+
+        debug(D_DEFLATE, "%llu: Compressing %zu new bytes starting from %zu (and %u left behind).", w->id, (w->response.data->len - w->response.sent), w->response.sent, w->response.zstream.avail_in);
+
+        // give the compressor all the data not passed through the compressor yet
+        if(w->response.data->len > w->response.sent) {
+            w->response.zstream.next_in = (Bytef *)&w->response.data->buffer[w->response.sent - w->response.zstream.avail_in];
+            w->response.zstream.avail_in += (uInt) (w->response.data->len - w->response.sent);
+        }
+
+        // reset the compressor output buffer
+        w->response.zstream.next_out = w->response.zbuffer;
+        w->response.zstream.avail_out = NETDATA_WEB_RESPONSE_ZLIB_CHUNK_SIZE;
+
+        // ask for FINISH if we have all the input
+        int flush = Z_SYNC_FLUSH;
+        if(w->mode == WEB_CLIENT_MODE_NORMAL
+            || (w->mode == WEB_CLIENT_MODE_FILECOPY && !web_client_has_wait_receive(w) && w->response.data->len == w->response.rlen)) {
+            flush = Z_FINISH;
+            debug(D_DEFLATE, "%llu: Requesting Z_FINISH, if possible.", w->id);
+        }
+        else {
+            debug(D_DEFLATE, "%llu: Requesting Z_SYNC_FLUSH.", w->id);
+        }
+
+        // compress
+        if(deflate(&w->response.zstream, flush) == Z_STREAM_ERROR) {
+            error("%llu: Compression failed. Closing down client.", w->id);
+            web_client_request_done(w);
+            return(-1);
+        }
+
+        w->response.zhave = NETDATA_WEB_RESPONSE_ZLIB_CHUNK_SIZE - w->response.zstream.avail_out;
+        w->response.zsent = 0;
+
+        // keep track of the bytes passed through the compressor
+        w->response.sent = w->response.data->len;
+
+        debug(D_DEFLATE, "%llu: Compression produced %zu bytes.", w->id, w->response.zhave);
+
+        // open a new chunk
+        ssize_t t2 = web_client_send_chunk_header(w, w->response.zhave);
+        if(t2 < 0) return t2;
+        t += t2;
+    }
+    
+    debug(D_WEB_CLIENT, "%llu: Sending %zu bytes of data (+%zd of chunk header).", w->id, w->response.zhave - w->response.zsent, t);
+
+    len = send(w->ofd, &w->response.zbuffer[w->response.zsent], (size_t) (w->response.zhave - w->response.zsent), MSG_DONTWAIT);
+    if(len > 0) {
+        w->stats_sent_bytes += len;
+        w->response.zsent += len;
+        len += t;
+        debug(D_WEB_CLIENT, "%llu: Sent %zd bytes.", w->id, len);
+    }
+    else if(len == 0) {
+        debug(D_WEB_CLIENT, "%llu: Did not send any bytes to the client (zhave = %zu, zsent = %zu, need to send = %zu).",
+            w->id, w->response.zhave, w->response.zsent, w->response.zhave - w->response.zsent);
+
+        WEB_CLIENT_IS_DEAD(w);
+    }
+    else {
+        debug(D_WEB_CLIENT, "%llu: Failed to send data to client.", w->id);
+        WEB_CLIENT_IS_DEAD(w);
+    }
+
+    return(len);
+}
+#endif // NETDATA_WITH_ZLIB
+
+ssize_t web_client_send(struct web_client *w) {
+#ifdef NETDATA_WITH_ZLIB
+    if(likely(w->response.zoutput)) return web_client_send_deflate(w);
+#endif // NETDATA_WITH_ZLIB
+
+    ssize_t bytes;
+
+    if(unlikely(w->response.data->len - w->response.sent == 0)) {
+        // there is nothing to send
+
+        debug(D_WEB_CLIENT, "%llu: Out of output data.", w->id);
+
+        // there can be two cases for this
+        // A. we have done everything
+        // B. we temporarily have nothing to send, waiting for the buffer to be filled by ifd
+
+        if(w->mode == WEB_CLIENT_MODE_FILECOPY && web_client_has_wait_receive(w) && w->response.rlen && w->response.rlen > w->response.data->len) {
+            // we have to wait, more data will come
+            debug(D_WEB_CLIENT, "%llu: Waiting for more data to become available.", w->id);
+            web_client_disable_wait_send(w);
+            return 0;
+        }
+
+        if(unlikely(!web_client_has_keepalive(w))) {
+            debug(D_WEB_CLIENT, "%llu: Closing (keep-alive is not enabled). %zu bytes sent.", w->id, w->response.sent);
+            WEB_CLIENT_IS_DEAD(w);
+            return 0;
+        }
+
+        web_client_request_done(w);
+        debug(D_WEB_CLIENT, "%llu: Done sending all data on socket. Waiting for next request on the same socket.", w->id);
+        return 0;
+    }
+
+    bytes = send(w->ofd, &w->response.data->buffer[w->response.sent], w->response.data->len - w->response.sent, MSG_DONTWAIT);
+    if(likely(bytes > 0)) {
+        w->stats_sent_bytes += bytes;
+        w->response.sent += bytes;
+        debug(D_WEB_CLIENT, "%llu: Sent %zd bytes.", w->id, bytes);
+    }
+    else if(likely(bytes == 0)) {
+        debug(D_WEB_CLIENT, "%llu: Did not send any bytes to the client.", w->id);
+        WEB_CLIENT_IS_DEAD(w);
+    }
+    else {
+        debug(D_WEB_CLIENT, "%llu: Failed to send data to client.", w->id);
+        WEB_CLIENT_IS_DEAD(w);
+    }
+
+    return(bytes);
+}
+
+ssize_t web_client_read_file(struct web_client *w)
+{
+    if(unlikely(w->response.rlen > w->response.data->size))
+        buffer_need_bytes(w->response.data, w->response.rlen - w->response.data->size);
+
+    if(unlikely(w->response.rlen <= w->response.data->len))
+        return 0;
+
+    ssize_t left = w->response.rlen - w->response.data->len;
+    ssize_t bytes = read(w->ifd, &w->response.data->buffer[w->response.data->len], (size_t)left);
+    if(likely(bytes > 0)) {
+        size_t old = w->response.data->len;
+        (void)old;
+
+        w->response.data->len += bytes;
+        w->response.data->buffer[w->response.data->len] = '\0';
+
+        debug(D_WEB_CLIENT, "%llu: Read %zd bytes.", w->id, bytes);
+        debug(D_WEB_DATA, "%llu: Read data: '%s'.", w->id, &w->response.data->buffer[old]);
+
+        web_client_enable_wait_send(w);
+
+        if(w->response.rlen && w->response.data->len >= w->response.rlen)
+            web_client_disable_wait_receive(w);
+    }
+    else if(likely(bytes == 0)) {
+        debug(D_WEB_CLIENT, "%llu: Out of input file data.", w->id);
+
+        // if we cannot read, it means we have an error on input.
+        // if however, we are copying a file from ifd to ofd, we should not return an error.
+        // in this case, the error should be generated when the file has been sent to the client.
+
+        // we are copying data from ifd to ofd
+        // let it finish copying...
+        web_client_disable_wait_receive(w);
+
+        debug(D_WEB_CLIENT, "%llu: Read the whole file.", w->id);
+
+        if(web_server_mode != WEB_SERVER_MODE_STATIC_THREADED) {
+            if (w->ifd != w->ofd) close(w->ifd);
+        }
+
+        w->ifd = w->ofd;
+    }
+    else {
+        debug(D_WEB_CLIENT, "%llu: read data failed.", w->id);
+        WEB_CLIENT_IS_DEAD(w);
+    }
+
+    return(bytes);
+}
+
+ssize_t web_client_receive(struct web_client *w)
+{
+    if(unlikely(w->mode == WEB_CLIENT_MODE_FILECOPY))
+        return web_client_read_file(w);
+
+    // do we have any space for more data?
+    buffer_need_bytes(w->response.data, NETDATA_WEB_REQUEST_RECEIVE_SIZE);
+
+    ssize_t left = w->response.data->size - w->response.data->len;
+    ssize_t bytes = recv(w->ifd, &w->response.data->buffer[w->response.data->len], (size_t) (left - 1), MSG_DONTWAIT);
+
+    if(likely(bytes > 0)) {
+        w->stats_received_bytes += bytes;
+
+        size_t old = w->response.data->len;
+        (void)old;
+
+        w->response.data->len += bytes;
+        w->response.data->buffer[w->response.data->len] = '\0';
+
+        debug(D_WEB_CLIENT, "%llu: Received %zd bytes.", w->id, bytes);
+        debug(D_WEB_DATA, "%llu: Received data: '%s'.", w->id, &w->response.data->buffer[old]);
+    }
+    else {
+        debug(D_WEB_CLIENT, "%llu: receive data failed.", w->id);
+        WEB_CLIENT_IS_DEAD(w);
+    }
+
+    return(bytes);
+}
diff --git a/web/server/web_client.h b/web/server/web_client.h
new file mode 100644
index 0000000..4263e25
--- /dev/null
+++ b/web/server/web_client.h
@@ -0,0 +1,176 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef NETDATA_WEB_CLIENT_H
+#define NETDATA_WEB_CLIENT_H 1
+
+#include "libnetdata/libnetdata.h"
+
+#ifdef NETDATA_WITH_ZLIB
+extern int web_enable_gzip,
+        web_gzip_level,
+        web_gzip_strategy;
+#endif /* NETDATA_WITH_ZLIB */
+
+extern int respect_web_browser_do_not_track_policy;
+extern char *web_x_frame_options;
+
+typedef enum web_client_mode {
+    WEB_CLIENT_MODE_NORMAL      = 0,
+    WEB_CLIENT_MODE_FILECOPY    = 1,
+    WEB_CLIENT_MODE_OPTIONS     = 2,
+    WEB_CLIENT_MODE_STREAM      = 3
+} WEB_CLIENT_MODE;
+
+typedef enum web_client_flags {
+    WEB_CLIENT_FLAG_DEAD              = 1 << 1, // if set, this client is dead
+
+    WEB_CLIENT_FLAG_KEEPALIVE         = 1 << 2, // if set, the web client will be re-used
+
+    WEB_CLIENT_FLAG_WAIT_RECEIVE      = 1 << 3, // if set, we are waiting more input data
+    WEB_CLIENT_FLAG_WAIT_SEND         = 1 << 4, // if set, we have data to send to the client
+
+    WEB_CLIENT_FLAG_DO_NOT_TRACK      = 1 << 5, // if set, we should not set cookies on this client
+    WEB_CLIENT_FLAG_TRACKING_REQUIRED = 1 << 6, // if set, we need to send cookies
+
+    WEB_CLIENT_FLAG_TCP_CLIENT        = 1 << 7, // if set, the client is using a TCP socket
+    WEB_CLIENT_FLAG_UNIX_CLIENT       = 1 << 8, // if set, the client is using a UNIX socket
+
+    WEB_CLIENT_FLAG_DONT_CLOSE_SOCKET = 1 << 9,  // don't close the socket when cleaning up (static-threaded web server)
+} WEB_CLIENT_FLAGS;
+
+//#ifdef HAVE_C___ATOMIC
+//#define web_client_flag_check(w, flag) (__atomic_load_n(&((w)->flags), __ATOMIC_SEQ_CST) & flag)
+//#define web_client_flag_set(w, flag)   __atomic_or_fetch(&((w)->flags), flag, __ATOMIC_SEQ_CST)
+//#define web_client_flag_clear(w, flag) __atomic_and_fetch(&((w)->flags), ~flag, __ATOMIC_SEQ_CST)
+//#else
+#define web_client_flag_check(w, flag) ((w)->flags & (flag))
+#define web_client_flag_set(w, flag)   (w)->flags |= flag
+#define web_client_flag_clear(w, flag) (w)->flags &= ~flag
+//#endif
+
+#define WEB_CLIENT_IS_DEAD(w) web_client_flag_set(w, WEB_CLIENT_FLAG_DEAD)
+#define web_client_check_dead(w) web_client_flag_check(w, WEB_CLIENT_FLAG_DEAD)
+
+#define web_client_has_keepalive(w) web_client_flag_check(w, WEB_CLIENT_FLAG_KEEPALIVE)
+#define web_client_enable_keepalive(w) web_client_flag_set(w, WEB_CLIENT_FLAG_KEEPALIVE)
+#define web_client_disable_keepalive(w) web_client_flag_clear(w, WEB_CLIENT_FLAG_KEEPALIVE)
+
+#define web_client_has_donottrack(w) web_client_flag_check(w, WEB_CLIENT_FLAG_DO_NOT_TRACK)
+#define web_client_enable_donottrack(w) web_client_flag_set(w, WEB_CLIENT_FLAG_DO_NOT_TRACK)
+#define web_client_disable_donottrack(w) web_client_flag_clear(w, WEB_CLIENT_FLAG_DO_NOT_TRACK)
+
+#define web_client_has_tracking_required(w) web_client_flag_check(w, WEB_CLIENT_FLAG_TRACKING_REQUIRED)
+#define web_client_enable_tracking_required(w) web_client_flag_set(w, WEB_CLIENT_FLAG_TRACKING_REQUIRED)
+#define web_client_disable_tracking_required(w) web_client_flag_clear(w, WEB_CLIENT_FLAG_TRACKING_REQUIRED)
+
+#define web_client_has_wait_receive(w) web_client_flag_check(w, WEB_CLIENT_FLAG_WAIT_RECEIVE)
+#define web_client_enable_wait_receive(w) web_client_flag_set(w, WEB_CLIENT_FLAG_WAIT_RECEIVE)
+#define web_client_disable_wait_receive(w) web_client_flag_clear(w, WEB_CLIENT_FLAG_WAIT_RECEIVE)
+
+#define web_client_has_wait_send(w) web_client_flag_check(w, WEB_CLIENT_FLAG_WAIT_SEND)
+#define web_client_enable_wait_send(w) web_client_flag_set(w, WEB_CLIENT_FLAG_WAIT_SEND)
+#define web_client_disable_wait_send(w) web_client_flag_clear(w, WEB_CLIENT_FLAG_WAIT_SEND)
+
+#define web_client_set_tcp(w) web_client_flag_set(w, WEB_CLIENT_FLAG_TCP_CLIENT)
+#define web_client_set_unix(w) web_client_flag_set(w, WEB_CLIENT_FLAG_UNIX_CLIENT)
+#define web_client_check_unix(w) web_client_flag_check(w, WEB_CLIENT_FLAG_UNIX_CLIENT)
+#define web_client_check_tcp(w) web_client_flag_check(w, WEB_CLIENT_FLAG_TCP_CLIENT)
+
+#define web_client_is_corkable(w) web_client_flag_check(w, WEB_CLIENT_FLAG_TCP_CLIENT)
+
+#define NETDATA_WEB_REQUEST_URL_SIZE 8192
+#define NETDATA_WEB_RESPONSE_ZLIB_CHUNK_SIZE 16384
+#define NETDATA_WEB_RESPONSE_HEADER_SIZE 4096
+#define NETDATA_WEB_REQUEST_COOKIE_SIZE 1024
+#define NETDATA_WEB_REQUEST_ORIGIN_HEADER_SIZE 1024
+#define NETDATA_WEB_RESPONSE_INITIAL_SIZE 16384
+#define NETDATA_WEB_REQUEST_RECEIVE_SIZE 16384
+#define NETDATA_WEB_REQUEST_MAX_SIZE 16384
+
+struct response {
+    BUFFER *header;                 // our response header
+    BUFFER *header_output;          // internal use
+    BUFFER *data;                   // our response data buffer
+
+    int code;                       // the HTTP response code
+
+    size_t rlen;                    // if non-zero, the excepted size of ifd (input of firecopy)
+    size_t sent;                    // current data length sent to output
+
+    int zoutput;                    // if set to 1, web_client_send() will send compressed data
+#ifdef NETDATA_WITH_ZLIB
+    z_stream zstream;               // zlib stream for sending compressed output to client
+    Bytef zbuffer[NETDATA_WEB_RESPONSE_ZLIB_CHUNK_SIZE]; // temporary buffer for storing compressed output
+    size_t zsent;                   // the compressed bytes we have sent to the client
+    size_t zhave;                   // the compressed bytes that we have received from zlib
+    unsigned int zinitialized:1;
+#endif /* NETDATA_WITH_ZLIB */
+
+};
+
+struct web_client {
+    unsigned long long id;
+
+    WEB_CLIENT_FLAGS flags;         // status flags for the client
+    WEB_CLIENT_MODE mode;           // the operational mode of the client
+    WEB_CLIENT_ACL acl;             // the access list of the client
+    int port_acl;                   // the operations permitted on the port the client connected to
+    char *auth_bearer_token;        // the Bearer auth token (if sent)
+    size_t header_parse_tries;
+    size_t header_parse_last_size;
+
+    int tcp_cork;                   // 1 = we have a cork on the socket
+
+    int ifd;
+    int ofd;
+
+    char client_ip[NI_MAXHOST+1];
+    char client_port[NI_MAXSERV+1];
+
+    char decoded_url[NETDATA_WEB_REQUEST_URL_SIZE + 1];  // we decode the URL in this buffer
+    char last_url[NETDATA_WEB_REQUEST_URL_SIZE+1];       // we keep a copy of the decoded URL here
+
+    struct timeval tv_in, tv_ready;
+
+    char cookie1[NETDATA_WEB_REQUEST_COOKIE_SIZE+1];
+    char cookie2[NETDATA_WEB_REQUEST_COOKIE_SIZE+1];
+    char origin[NETDATA_WEB_REQUEST_ORIGIN_HEADER_SIZE+1];
+    char *user_agent;
+
+    struct response response;
+
+    size_t stats_received_bytes;
+    size_t stats_sent_bytes;
+
+    // cache of web_client allocations
+    struct web_client *prev;        // maintain a linked list of web clients
+    struct web_client *next;        // for the web servers that need it
+
+    // MULTI-THREADED WEB SERVER MEMBERS
+    netdata_thread_t thread;        // the thread servicing this client
+    volatile int running;           // 1 when the thread runs, 0 otherwise
+
+    // STATIC-THREADED WEB SERVER MEMBERS
+    size_t pollinfo_slot;           // POLLINFO slot of the web client
+    size_t pollinfo_filecopy_slot;  // POLLINFO slot of the file read
+};
+
+extern uid_t web_files_uid(void);
+extern uid_t web_files_gid(void);
+
+extern int web_client_permission_denied(struct web_client *w);
+
+extern ssize_t web_client_send(struct web_client *w);
+extern ssize_t web_client_receive(struct web_client *w);
+extern ssize_t web_client_read_file(struct web_client *w);
+
+extern void web_client_process_request(struct web_client *w);
+extern void web_client_request_done(struct web_client *w);
+
+extern void buffer_data_options2string(BUFFER *wb, uint32_t options);
+
+extern int mysendfile(struct web_client *w, char *filename);
+
+#include "daemon/common.h"
+
+#endif
diff --git a/web/server/web_client_cache.c b/web/server/web_client_cache.c
new file mode 100644
index 0000000..ab47056
--- /dev/null
+++ b/web/server/web_client_cache.c
@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#define WEB_SERVER_INTERNALS 1
+#include "web_client_cache.h"
+
+// ----------------------------------------------------------------------------
+// allocate and free web_clients
+
+static void web_client_zero(struct web_client *w) {
+    // zero everything about it - but keep the buffers
+
+    // remember the pointers to the buffers
+    BUFFER *b1 = w->response.data;
+    BUFFER *b2 = w->response.header;
+    BUFFER *b3 = w->response.header_output;
+
+    // empty the buffers
+    buffer_flush(b1);
+    buffer_flush(b2);
+    buffer_flush(b3);
+
+    freez(w->user_agent);
+
+    // zero everything
+    memset(w, 0, sizeof(struct web_client));
+
+    // restore the pointers of the buffers
+    w->response.data = b1;
+    w->response.header = b2;
+    w->response.header_output = b3;
+}
+
+static void web_client_free(struct web_client *w) {
+    buffer_free(w->response.header_output);
+    buffer_free(w->response.header);
+    buffer_free(w->response.data);
+    freez(w->user_agent);
+    freez(w);
+}
+
+static struct web_client *web_client_alloc(void) {
+    struct web_client *w = callocz(1, sizeof(struct web_client));
+    w->response.data = buffer_create(NETDATA_WEB_RESPONSE_INITIAL_SIZE);
+    w->response.header = buffer_create(NETDATA_WEB_RESPONSE_HEADER_SIZE);
+    w->response.header_output = buffer_create(NETDATA_WEB_RESPONSE_HEADER_SIZE);
+    return w;
+}
+
+// ----------------------------------------------------------------------------
+// web clients caching
+
+// When clients connect and disconnect, avoid allocating and releasing memory.
+// Instead, when new clients get connected, reuse any memory previously allocated
+// for serving web clients that are now disconnected.
+
+// The size of the cache is adaptive. It caches the structures of 2x
+// the number of currently connected clients.
+
+// Comments per server:
+// SINGLE-THREADED : 1 cache is maintained
+// MULTI-THREADED  : 1 cache is maintained
+// STATIC-THREADED : 1 cache for each thred of the web server
+
+__thread struct clients_cache web_clients_cache = {
+        .pid = 0,
+        .used = NULL,
+        .used_count = 0,
+        .avail = NULL,
+        .avail_count = 0,
+        .allocated = 0,
+        .reused = 0
+};
+
+inline void web_client_cache_verify(int force) {
+#ifdef NETDATA_INTERNAL_CHECKS
+    static __thread size_t count = 0;
+    count++;
+
+    if(unlikely(force || count > 1000)) {
+        count = 0;
+
+        struct web_client *w;
+        size_t used = 0, avail = 0;
+        for(w = web_clients_cache.used; w ; w = w->next) used++;
+        for(w = web_clients_cache.avail; w ; w = w->next) avail++;
+
+        info("web_client_cache has %zu (%zu) used and %zu (%zu) available clients, allocated %zu, reused %zu (hit %zu%%)."
+             , used, web_clients_cache.used_count
+             , avail, web_clients_cache.avail_count
+             , web_clients_cache.allocated
+             , web_clients_cache.reused
+             , (web_clients_cache.allocated + web_clients_cache.reused)?(web_clients_cache.reused * 100 / (web_clients_cache.allocated + web_clients_cache.reused)):0
+        );
+    }
+#else
+    if(unlikely(force)) {
+        info("web_client_cache has %zu used and %zu available clients, allocated %zu, reused %zu (hit %zu%%)."
+             , web_clients_cache.used_count
+             , web_clients_cache.avail_count
+             , web_clients_cache.allocated
+             , web_clients_cache.reused
+             , (web_clients_cache.allocated + web_clients_cache.reused)?(web_clients_cache.reused * 100 / (web_clients_cache.allocated + web_clients_cache.reused)):0
+            );
+    }
+#endif
+}
+
+// destroy the cache and free all the memory it uses
+void web_client_cache_destroy(void) {
+#ifdef NETDATA_INTERNAL_CHECKS
+    if(unlikely(web_clients_cache.pid != 0 && web_clients_cache.pid != gettid()))
+        error("Oops! wrong thread accessing the cache. Expected %d, found %d", (int)web_clients_cache.pid, (int)gettid());
+
+    web_client_cache_verify(1);
+#endif
+
+    netdata_thread_disable_cancelability();
+
+    struct web_client *w, *t;
+
+    w = web_clients_cache.used;
+    while(w) {
+        t = w;
+        w = w->next;
+        web_client_free(t);
+    }
+    web_clients_cache.used = NULL;
+    web_clients_cache.used_count = 0;
+
+    w = web_clients_cache.avail;
+    while(w) {
+        t = w;
+        w = w->next;
+        web_client_free(t);
+    }
+    web_clients_cache.avail = NULL;
+    web_clients_cache.avail_count = 0;
+
+    netdata_thread_enable_cancelability();
+}
+
+struct web_client *web_client_get_from_cache_or_allocate() {
+
+#ifdef NETDATA_INTERNAL_CHECKS
+    if(unlikely(web_clients_cache.pid == 0))
+        web_clients_cache.pid = gettid();
+
+    if(unlikely(web_clients_cache.pid != 0 && web_clients_cache.pid != gettid()))
+        error("Oops! wrong thread accessing the cache. Expected %d, found %d", (int)web_clients_cache.pid, (int)gettid());
+#endif
+
+    netdata_thread_disable_cancelability();
+
+    struct web_client *w = web_clients_cache.avail;
+
+    if(w) {
+        // get it from avail
+        if (w == web_clients_cache.avail) web_clients_cache.avail = w->next;
+        if(w->prev) w->prev->next = w->next;
+        if(w->next) w->next->prev = w->prev;
+        web_clients_cache.avail_count--;
+        web_client_zero(w);
+        web_clients_cache.reused++;
+    }
+    else {
+        // allocate it
+        w = web_client_alloc();
+        web_clients_cache.allocated++;
+    }
+
+    // link it to used web clients
+    if (web_clients_cache.used) web_clients_cache.used->prev = w;
+    w->next = web_clients_cache.used;
+    w->prev = NULL;
+    web_clients_cache.used = w;
+    web_clients_cache.used_count++;
+
+    // initialize it
+    w->id = web_client_connected();
+    w->mode = WEB_CLIENT_MODE_NORMAL;
+
+    netdata_thread_enable_cancelability();
+
+    return w;
+}
+
+void web_client_release(struct web_client *w) {
+#ifdef NETDATA_INTERNAL_CHECKS
+    if(unlikely(web_clients_cache.pid != 0 && web_clients_cache.pid != gettid()))
+        error("Oops! wrong thread accessing the cache. Expected %d, found %d", (int)web_clients_cache.pid, (int)gettid());
+
+    if(unlikely(w->running))
+        error("%llu: releasing web client from %s port %s, but it still running.", w->id, w->client_ip, w->client_port);
+#endif
+
+    debug(D_WEB_CLIENT_ACCESS, "%llu: Closing web client from %s port %s.", w->id, w->client_ip, w->client_port);
+
+    web_server_log_connection(w, "DISCONNECTED");
+    web_client_request_done(w);
+    web_client_disconnected();
+
+    netdata_thread_disable_cancelability();
+
+    if(web_server_mode != WEB_SERVER_MODE_STATIC_THREADED) {
+        if (w->ifd != -1) close(w->ifd);
+        if (w->ofd != -1 && w->ofd != w->ifd) close(w->ofd);
+        w->ifd = w->ofd = -1;
+    }
+
+    // unlink it from the used
+    if (w == web_clients_cache.used) web_clients_cache.used = w->next;
+    if(w->prev) w->prev->next = w->next;
+    if(w->next) w->next->prev = w->prev;
+    web_clients_cache.used_count--;
+
+    if(web_clients_cache.avail_count >= 2 * web_clients_cache.used_count) {
+        // we have too many of them - free it
+        web_client_free(w);
+    }
+    else {
+        // link it to the avail
+        if (web_clients_cache.avail) web_clients_cache.avail->prev = w;
+        w->next = web_clients_cache.avail;
+        w->prev = NULL;
+        web_clients_cache.avail = w;
+        web_clients_cache.avail_count++;
+    }
+
+    netdata_thread_enable_cancelability();
+}
+
diff --git a/web/server/web_client_cache.h b/web/server/web_client_cache.h
new file mode 100644
index 0000000..f638880
--- /dev/null
+++ b/web/server/web_client_cache.h
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef NETDATA_WEB_CLIENT_CACHE_H
+#define NETDATA_WEB_CLIENT_CACHE_H
+
+#include "libnetdata/libnetdata.h"
+#include "web_client.h"
+
+struct clients_cache {
+    pid_t pid;
+
+    struct web_client *used;    // the structures of the currently connected clients
+    size_t used_count;          // the count the currently connected clients
+
+    struct web_client *avail;   // the cached structures, available for future clients
+    size_t avail_count;         // the number of cached structures
+
+    size_t reused;              // the number of re-uses
+    size_t allocated;           // the number of allocations
+};
+
+extern __thread struct clients_cache web_clients_cache;
+
+extern void web_client_release(struct web_client *w);
+extern struct web_client *web_client_get_from_cache_or_allocate();
+extern void web_client_cache_destroy(void);
+extern void web_client_cache_verify(int force);
+
+#include "web_server.h"
+
+#endif //NETDATA_WEB_CLIENT_CACHE_H
diff --git a/web/server/web_server.c b/web/server/web_server.c
new file mode 100644
index 0000000..11f7edf
--- /dev/null
+++ b/web/server/web_server.c
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#define WEB_SERVER_INTERNALS 1
+#include "web_server.h"
+
+WEB_SERVER_MODE web_server_mode = WEB_SERVER_MODE_STATIC_THREADED;
+
+// --------------------------------------------------------------------------------------
+
+WEB_SERVER_MODE web_server_mode_id(const char *mode) {
+    if(!strcmp(mode, "none"))
+        return WEB_SERVER_MODE_NONE;
+    else
+        return WEB_SERVER_MODE_STATIC_THREADED;
+
+}
+
+const char *web_server_mode_name(WEB_SERVER_MODE id) {
+    switch(id) {
+        case WEB_SERVER_MODE_NONE:
+            return "none";
+        default:
+        case WEB_SERVER_MODE_STATIC_THREADED:
+            return "static-threaded";
+    }
+}
+
+// --------------------------------------------------------------------------------------
+// API sockets
+
+LISTEN_SOCKETS api_sockets = {
+		.config          = &netdata_config,
+		.config_section  = CONFIG_SECTION_WEB,
+		.default_bind_to = "*",
+		.default_port    = API_LISTEN_PORT,
+		.backlog         = API_LISTEN_BACKLOG
+};
+
+void debug_sockets() {
+	BUFFER *wb = buffer_create(256 * sizeof(char));
+	int i;
+
+	for(i = 0 ; i < (int)api_sockets.opened ; i++) {
+		buffer_strcat(wb, (api_sockets.fds_acl_flags[i] & WEB_CLIENT_ACL_NOCHECK)?"NONE ":"");
+		buffer_strcat(wb, (api_sockets.fds_acl_flags[i] & WEB_CLIENT_ACL_DASHBOARD)?"dashboard ":"");
+		buffer_strcat(wb, (api_sockets.fds_acl_flags[i] & WEB_CLIENT_ACL_REGISTRY)?"registry ":"");
+		buffer_strcat(wb, (api_sockets.fds_acl_flags[i] & WEB_CLIENT_ACL_BADGE)?"badges ":"");
+		buffer_strcat(wb, (api_sockets.fds_acl_flags[i] & WEB_CLIENT_ACL_MGMT)?"management ":"");
+		buffer_strcat(wb, (api_sockets.fds_acl_flags[i] & WEB_CLIENT_ACL_STREAMING)?"streaming ":"");
+		buffer_strcat(wb, (api_sockets.fds_acl_flags[i] & WEB_CLIENT_ACL_NETDATACONF)?"netdata.conf ":"");
+		debug(D_WEB_CLIENT, "Socket fd %d name '%s' acl_flags: %s",
+			  i,
+			  api_sockets.fds_names[i],
+			  buffer_tostring(wb));
+		buffer_reset(wb);
+	}
+	buffer_free(wb);
+}
+
+void api_listen_sockets_setup(void) {
+	int socks = listen_sockets_setup(&api_sockets);
+
+	if(!socks)
+		fatal("LISTENER: Cannot listen on any API socket. Exiting...");
+
+	if(unlikely(debug_flags & D_WEB_CLIENT))
+		debug_sockets();
+
+	return;
+}
+
+
+// --------------------------------------------------------------------------------------
+// access lists
+
+SIMPLE_PATTERN *web_allow_connections_from = NULL;
+
+// WEB_CLIENT_ACL
+SIMPLE_PATTERN *web_allow_dashboard_from = NULL;
+SIMPLE_PATTERN *web_allow_registry_from = NULL;
+SIMPLE_PATTERN *web_allow_badges_from = NULL;
+SIMPLE_PATTERN *web_allow_mgmt_from = NULL;
+SIMPLE_PATTERN *web_allow_streaming_from = NULL;
+SIMPLE_PATTERN *web_allow_netdataconf_from = NULL;
+
+void web_client_update_acl_matches(struct web_client *w) {
+    w->acl = WEB_CLIENT_ACL_NONE;
+
+    if(!web_allow_dashboard_from || simple_pattern_matches(web_allow_dashboard_from, w->client_ip))
+        w->acl |= WEB_CLIENT_ACL_DASHBOARD;
+
+    if(!web_allow_registry_from || simple_pattern_matches(web_allow_registry_from, w->client_ip))
+        w->acl |= WEB_CLIENT_ACL_REGISTRY;
+
+    if(!web_allow_badges_from || simple_pattern_matches(web_allow_badges_from, w->client_ip))
+        w->acl |= WEB_CLIENT_ACL_BADGE;
+
+    if(!web_allow_mgmt_from || simple_pattern_matches(web_allow_mgmt_from, w->client_ip))
+        w->acl |= WEB_CLIENT_ACL_MGMT;
+
+    if(!web_allow_streaming_from || simple_pattern_matches(web_allow_streaming_from, w->client_ip))
+        w->acl |= WEB_CLIENT_ACL_STREAMING;
+
+    if(!web_allow_netdataconf_from || simple_pattern_matches(web_allow_netdataconf_from, w->client_ip))
+        w->acl |= WEB_CLIENT_ACL_NETDATACONF;
+
+    w->acl &= w->port_acl;
+}
+
+
+// --------------------------------------------------------------------------------------
+
+void web_server_log_connection(struct web_client *w, const char *msg) {
+    log_access("%llu: %d '[%s]:%s' '%s'", w->id, gettid(), w->client_ip, w->client_port, msg);
+}
+
+// --------------------------------------------------------------------------------------
+
+void web_client_initialize_connection(struct web_client *w) {
+    int flag = 1;
+
+    if(unlikely(web_client_check_tcp(w) && setsockopt(w->ifd, IPPROTO_TCP, TCP_NODELAY, (char *) &flag, sizeof(int)) != 0))
+        debug(D_WEB_CLIENT, "%llu: failed to enable TCP_NODELAY on socket fd %d.", w->id, w->ifd);
+
+    flag = 1;
+    if(unlikely(setsockopt(w->ifd, SOL_SOCKET, SO_KEEPALIVE, (char *) &flag, sizeof(int)) != 0))
+        debug(D_WEB_CLIENT, "%llu: failed to enable SO_KEEPALIVE on socket fd %d.", w->id, w->ifd);
+
+    web_client_update_acl_matches(w);
+
+    w->origin[0] = '*'; w->origin[1] = '\0';
+    w->cookie1[0] = '\0'; w->cookie2[0] = '\0';
+    freez(w->user_agent); w->user_agent = NULL;
+
+    web_client_enable_wait_receive(w);
+
+    web_server_log_connection(w, "CONNECTED");
+
+    web_client_cache_verify(0);
+}
+
+
diff --git a/web/server/web_server.h b/web/server/web_server.h
new file mode 100644
index 0000000..e7c2dd4
--- /dev/null
+++ b/web/server/web_server.h
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef NETDATA_WEB_SERVER_H
+#define NETDATA_WEB_SERVER_H 1
+
+#include "libnetdata/libnetdata.h"
+#include "web_client.h"
+
+#ifndef API_LISTEN_PORT
+#define API_LISTEN_PORT 19999
+#endif
+
+#ifndef API_LISTEN_BACKLOG
+#define API_LISTEN_BACKLOG 4096
+#endif
+
+typedef enum web_server_mode {
+    WEB_SERVER_MODE_STATIC_THREADED,
+    WEB_SERVER_MODE_NONE
+} WEB_SERVER_MODE;
+
+extern SIMPLE_PATTERN *web_allow_connections_from;
+extern SIMPLE_PATTERN *web_allow_dashboard_from;
+extern SIMPLE_PATTERN *web_allow_registry_from;
+extern SIMPLE_PATTERN *web_allow_badges_from;
+extern SIMPLE_PATTERN *web_allow_streaming_from;
+extern SIMPLE_PATTERN *web_allow_netdataconf_from;
+extern SIMPLE_PATTERN *web_allow_mgmt_from;
+
+extern WEB_SERVER_MODE web_server_mode;
+
+extern WEB_SERVER_MODE web_server_mode_id(const char *mode);
+extern const char *web_server_mode_name(WEB_SERVER_MODE id);
+
+extern void api_listen_sockets_setup(void);
+
+#define DEFAULT_TIMEOUT_TO_RECEIVE_FIRST_WEB_REQUEST 60
+#define DEFAULT_DISCONNECT_IDLE_WEB_CLIENTS_AFTER_SECONDS 60
+extern int web_client_timeout;
+extern int web_client_first_request_timeout;
+extern long web_client_streaming_rate_t;
+
+#ifdef WEB_SERVER_INTERNALS
+extern LISTEN_SOCKETS api_sockets;
+extern void web_client_update_acl_matches(struct web_client *w);
+extern void web_server_log_connection(struct web_client *w, const char *msg);
+extern void web_client_initialize_connection(struct web_client *w);
+extern struct web_client *web_client_create_on_listenfd(int listener);
+
+#include "web_client_cache.h"
+#endif // WEB_SERVER_INTERNALS
+
+#include "static/static-threaded.h"
+
+#include "daemon/common.h"
+
+#endif /* NETDATA_WEB_SERVER_H */