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netdata_netdata/web/server/web_server.c
Andrew Moss 01aaa90939
Fixing DNS-lookup performance issue on FreeBSD. ()
Our default configuration includes:
   allow connections from = localhost *
   allow management from = localhost

The problem occurs when a connection is received that passes the `allow connections` pattern
match, but fails the ACL check for `allow management`. During the failure processing path the
DNS lookup is triggered to allow the FQDN to be checked against the pattern. On a FreeBSD
system this lookup fails more slowly than linux and causes a visible performance problem
during stress-testing.

The fix adds a heuristic to analyse the patterns and determine if it is possible to match a DNS name,
or only match a numeric IP address (either IPv4 or IPv6), or only match a constant value. This
heuristic is used to disable the DNS checks when they cannot produce anything that may match
the pattern. Each heuristic is evaluated once, when the configuration is loaded, not per-connection to the agent.

Because the heuristic is not exact it can be overridden using the new config options for each of the ACL connection filters to set it to "yes", "no" or "heuristic". The default for everything *except* the netdata.conf ACL is "heuristic". Because of the numeric-patterns in the netdata.conf ACL the default is set to "no".
2019-10-24 20:44:56 +02:00

159 lines
5.7 KiB
C

// 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;
int web_allow_connections_dns;
// WEB_CLIENT_ACL
SIMPLE_PATTERN *web_allow_dashboard_from = NULL;
int web_allow_dashboard_dns;
SIMPLE_PATTERN *web_allow_registry_from = NULL;
int web_allow_registry_dns;
SIMPLE_PATTERN *web_allow_badges_from = NULL;
int web_allow_badges_dns;
SIMPLE_PATTERN *web_allow_mgmt_from = NULL;
int web_allow_mgmt_dns;
SIMPLE_PATTERN *web_allow_streaming_from = NULL;
int web_allow_streaming_dns;
SIMPLE_PATTERN *web_allow_netdataconf_from = NULL;
int web_allow_netdataconf_dns;
void web_client_update_acl_matches(struct web_client *w) {
w->acl = WEB_CLIENT_ACL_NONE;
if (!web_allow_dashboard_from ||
connection_allowed(w->ifd, w->client_ip, w->client_host, sizeof(w->client_host),
web_allow_dashboard_from, "dashboard", web_allow_dashboard_dns))
w->acl |= WEB_CLIENT_ACL_DASHBOARD;
if (!web_allow_registry_from ||
connection_allowed(w->ifd, w->client_ip, w->client_host, sizeof(w->client_host),
web_allow_registry_from, "registry", web_allow_registry_dns))
w->acl |= WEB_CLIENT_ACL_REGISTRY;
if (!web_allow_badges_from ||
connection_allowed(w->ifd, w->client_ip, w->client_host, sizeof(w->client_host),
web_allow_badges_from, "badges", web_allow_badges_dns))
w->acl |= WEB_CLIENT_ACL_BADGE;
if (!web_allow_mgmt_from ||
connection_allowed(w->ifd, w->client_ip, w->client_host, sizeof(w->client_host),
web_allow_mgmt_from, "management", web_allow_mgmt_dns))
w->acl |= WEB_CLIENT_ACL_MGMT;
if (!web_allow_streaming_from ||
connection_allowed(w->ifd, w->client_ip, w->client_host, sizeof(w->client_host),
web_allow_streaming_from, "streaming", web_allow_streaming_dns))
w->acl |= WEB_CLIENT_ACL_STREAMING;
if (!web_allow_netdataconf_from ||
connection_allowed(w->ifd, w->client_ip, w->client_host, sizeof(w->client_host),
web_allow_netdataconf_from, "netdata.conf", web_allow_netdataconf_dns))
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);
}