Currently we can only change initcwnd/initrwnd in the following way, and it does not store persistently:
sudo ip route change default via 192.168.1.1 dev tun0 initcwnd 20
sudo ip route change default via 192.168.1.1 dev tun0 initrwnd 20
For more details about initcwnd/initrwnd, please look at:
http://hjzhao.blogspot.com/2012/05/increase-initcwnd-for-performance.html
http://www.cdnplanet.com/blog/tune-tcp-initcwnd-for-optimum-performance
or google 'initcwnd initrwnd'
This work allows to configure the initcwnd and initrwnd.
Closes #2118
</para>
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>InitialCongestionWindow=</varname></term>
+ <listitem>
+ <para>The TCP initial congestion window or <literal>InitialCongestionWindow</literal> is used during the start
+ of a TCP connection. During the start of a TCP session, when a client requests for a resource, the server's initial congestion window
+ determines how many data packets will be sent during the initial burst of data. Takes a number between between 1 and 4294967295 (2^32 - 1).
+ Defaults to unset.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><varname>InitialAdvertisedReceiveWindow=</varname></term>
+ <listitem>
+ <para>The TCP receive window size or <literal>InitialAdvertisedReceiveWindow</literal> is the amount of receive data (in bytes)
+ that can be buffered at one time on a connection. The sending host can send only that amount of data before waiting for
+ an acknowledgment and window update from the receiving host. Takes a number between 1 and 4294967295 (2^32 - 1). Defaults to unset.
+ </para>
+ </listitem>
+ </varlistentry>
</variablelist>
</refsect1>
[RTAX_INITCWND] = { .type = NETLINK_TYPE_U32 },
[RTAX_FEATURES] = { .type = NETLINK_TYPE_U32 },
[RTAX_RTO_MIN] = { .type = NETLINK_TYPE_U32 },
+ [RTAX_INITRWND] = { .type = NETLINK_TYPE_U32 },
};
static const NLTypeSystem rtnl_route_metrics_type_system = {
Route.IPv6Preference, config_parse_ipv6_route_preference, 0, 0
Route.Protocol, config_parse_route_protocol, 0, 0
Route.Type, config_parse_route_type, 0, 0
+Route.InitialCongestionWindow, config_parse_tcp_window, 0, 0
+Route.InitialAdvertisedReceiveWindow, config_parse_tcp_window, 0, 0
DHCP.ClientIdentifier, config_parse_dhcp_client_identifier, 0, offsetof(Network, dhcp_client_identifier)
DHCP.UseDNS, config_parse_bool, 0, offsetof(Network, dhcp_use_dns)
DHCP.UseNTP, config_parse_bool, 0, offsetof(Network, dhcp_use_ntp)
return log_error_errno(r, "Could not append RTAX_MTU attribute: %m");
}
+ if (route->initcwnd) {
+ r = sd_netlink_message_append_u32(req, RTAX_INITCWND, route->initcwnd);
+ if (r < 0)
+ return log_error_errno(r, "Could not append RTAX_INITCWND attribute: %m");
+ }
+
+ if (route->initrwnd) {
+ r = sd_netlink_message_append_u32(req, RTAX_INITRWND, route->initrwnd);
+ if (r < 0)
+ return log_error_errno(r, "Could not append RTAX_INITRWND attribute: %m");
+ }
+
r = sd_netlink_message_close_container(req);
if (r < 0)
return log_error_errno(r, "Could not append RTA_METRICS attribute: %m");
return 0;
}
+
+int config_parse_tcp_window(const char *unit,
+ const char *filename,
+ unsigned line,
+ const char *section,
+ unsigned section_line,
+ const char *lvalue,
+ int ltype,
+ const char *rvalue,
+ void *data,
+ void *userdata) {
+ Network *network = userdata;
+ _cleanup_route_free_ Route *n = NULL;
+ uint32_t k;
+ int r;
+
+ assert(filename);
+ assert(section);
+ assert(lvalue);
+ assert(rvalue);
+ assert(data);
+
+ r = route_new_static(network, filename, section_line, &n);
+ if (r < 0)
+ return r;
+
+ r = safe_atou32(rvalue, &k);
+ if (r < 0) {
+ log_syntax(unit, LOG_ERR, filename, line, r,
+ "Could not parse TCP %s \"%s\", ignoring assignment: %m", rvalue, lvalue);
+ return 0;
+ }
+
+ if (streq(lvalue, "InitialCongestionWindow"))
+ n->initcwnd = k;
+ else if (streq(lvalue, "InitialAdvertisedReceiveWindow"))
+ n->initrwnd = k;
+ else {
+ log_syntax(unit, LOG_ERR, filename, line, 0, "Failed to parse TCP %s: %s", lvalue, rvalue);
+ return 0;
+ }
+
+ n = NULL;
+
+ return 0;
+}
uint32_t priority; /* note that ip(8) calls this 'metric' */
uint32_t table;
uint32_t mtu;
+ uint32_t initcwnd;
+ uint32_t initrwnd;
unsigned char pref;
unsigned flags;
int config_parse_ipv6_route_preference(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
int config_parse_route_protocol(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
int config_parse_route_type(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
+int config_parse_tcp_window(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);