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Systemd/src/network/networkd-sysctl.c

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <netinet/in.h>
#include <linux/if.h>
#include "missing_network.h"
#include "networkd-link.h"
#include "networkd-network.h"
#include "networkd-sysctl.h"
#include "socket-util.h"
#include "string-table.h"
#include "sysctl-util.h"
static int link_update_ipv6_sysctl(Link *link) {
assert(link);
if (link->flags & IFF_LOOPBACK)
return 0;
if (!link_ipv6_enabled(link))
return 0;
return sysctl_write_ip_property_boolean(AF_INET6, link->ifname, "disable_ipv6", false);
}
static int link_set_proxy_arp(Link *link) {
assert(link);
if (link->flags & IFF_LOOPBACK)
return 0;
if (!link->network)
return 0;
if (link->network->proxy_arp < 0)
return 0;
return sysctl_write_ip_property_boolean(AF_INET, link->ifname, "proxy_arp", link->network->proxy_arp > 0);
}
static bool link_ip_forward_enabled(Link *link, int family) {
assert(link);
assert(IN_SET(family, AF_INET, AF_INET6));
if (family == AF_INET6 && !socket_ipv6_is_supported())
return false;
if (link->flags & IFF_LOOPBACK)
return false;
if (!link->network)
return false;
return link->network->ip_forward & (family == AF_INET ? ADDRESS_FAMILY_IPV4 : ADDRESS_FAMILY_IPV6);
}
static int link_set_ipv4_forward(Link *link) {
assert(link);
if (!link_ip_forward_enabled(link, AF_INET))
return 0;
/* We propagate the forwarding flag from one interface to the
* global setting one way. This means: as long as at least one
* interface was configured at any time that had IP forwarding
* enabled the setting will stay on for good. We do this
* primarily to keep IPv4 and IPv6 packet forwarding behaviour
* somewhat in sync (see below). */
return sysctl_write_ip_property(AF_INET, NULL, "ip_forward", "1");
}
static int link_set_ipv6_forward(Link *link) {
assert(link);
if (!link_ip_forward_enabled(link, AF_INET6))
return 0;
/* On Linux, the IPv6 stack does not know a per-interface
* packet forwarding setting: either packet forwarding is on
* for all, or off for all. We hence don't bother with a
* per-interface setting, but simply propagate the interface
* flag, if it is set, to the global flag, one-way. Note that
* while IPv4 would allow a per-interface flag, we expose the
* same behaviour there and also propagate the setting from
* one to all, to keep things simple (see above). */
return sysctl_write_ip_property(AF_INET6, "all", "forwarding", "1");
}
static int link_set_ipv6_privacy_extensions(Link *link) {
assert(link);
if (!socket_ipv6_is_supported())
return 0;
if (link->flags & IFF_LOOPBACK)
return 0;
if (!link->network)
return 0;
return sysctl_write_ip_property_int(AF_INET6, link->ifname, "use_tempaddr", (int) link->network->ipv6_privacy_extensions);
}
static int link_set_ipv6_accept_ra(Link *link) {
assert(link);
/* Make this a NOP if IPv6 is not available */
if (!socket_ipv6_is_supported())
return 0;
if (link->flags & IFF_LOOPBACK)
return 0;
if (!link->network)
return 0;
return sysctl_write_ip_property(AF_INET6, link->ifname, "accept_ra", "0");
}
static int link_set_ipv6_dad_transmits(Link *link) {
assert(link);
/* Make this a NOP if IPv6 is not available */
if (!socket_ipv6_is_supported())
return 0;
if (link->flags & IFF_LOOPBACK)
return 0;
if (!link->network)
return 0;
if (link->network->ipv6_dad_transmits < 0)
return 0;
return sysctl_write_ip_property_int(AF_INET6, link->ifname, "dad_transmits", link->network->ipv6_dad_transmits);
}
static int link_set_ipv6_hop_limit(Link *link) {
assert(link);
/* Make this a NOP if IPv6 is not available */
if (!socket_ipv6_is_supported())
return 0;
if (link->flags & IFF_LOOPBACK)
return 0;
if (!link->network)
return 0;
if (link->network->ipv6_hop_limit < 0)
return 0;
return sysctl_write_ip_property_int(AF_INET6, link->ifname, "hop_limit", link->network->ipv6_hop_limit);
}
static int link_set_ipv4_accept_local(Link *link) {
assert(link);
if (link->flags & IFF_LOOPBACK)
return 0;
if (link->network->ipv4_accept_local < 0)
return 0;
return sysctl_write_ip_property_boolean(AF_INET, link->ifname, "accept_local", link->network->ipv4_accept_local > 0);
}
int link_set_sysctl(Link *link) {
int r;
assert(link);
/* If IPv6 configured that is static IPv6 address and IPv6LL autoconfiguration is enabled
* for this interface, then enable IPv6 */
r = link_update_ipv6_sysctl(link);
if (r < 0)
log_link_warning_errno(link, r, "Cannot enable IPv6, ignoring: %m");
r = link_set_proxy_arp(link);
if (r < 0)
log_link_warning_errno(link, r, "Cannot configure proxy ARP for interface, ignoring: %m");
r = link_set_ipv4_forward(link);
if (r < 0)
log_link_warning_errno(link, r, "Cannot turn on IPv4 packet forwarding, ignoring: %m");
r = link_set_ipv6_forward(link);
if (r < 0)
log_link_warning_errno(link, r, "Cannot configure IPv6 packet forwarding, ignoring: %m");;
r = link_set_ipv6_privacy_extensions(link);
if (r < 0)
log_link_warning_errno(link, r, "Cannot configure IPv6 privacy extensions for interface, ignoring: %m");
r = link_set_ipv6_accept_ra(link);
if (r < 0)
log_link_warning_errno(link, r, "Cannot disable kernel IPv6 accept_ra for interface, ignoring: %m");
r = link_set_ipv6_dad_transmits(link);
if (r < 0)
log_link_warning_errno(link, r, "Cannot set IPv6 dad transmits for interface, ignoring: %m");
r = link_set_ipv6_hop_limit(link);
if (r < 0)
log_link_warning_errno(link, r, "Cannot set IPv6 hop limit for interface, ignoring: %m");
r = link_set_ipv4_accept_local(link);
if (r < 0)
log_link_warning_errno(link, r, "Cannot set IPv4 accept_local flag for interface, ignoring: %m");
/* If promote_secondaries is not set, DHCP will work only as long as the IP address does not
* changes between leases. The kernel will remove all secondary IP addresses of an interface
* otherwise. The way systemd-networkd works is that the new IP of a lease is added as a
* secondary IP and when the primary one expires it relies on the kernel to promote the
* secondary IP. See also https://github.com/systemd/systemd/issues/7163 */
r = sysctl_write_ip_property_boolean(AF_INET, link->ifname, "promote_secondaries", true);
if (r < 0)
log_link_warning_errno(link, r, "Cannot enable promote_secondaries for interface, ignoring: %m");
return 0;
}
int link_set_ipv6_mtu(Link *link) {
int r;
assert(link);
/* Make this a NOP if IPv6 is not available */
if (!socket_ipv6_is_supported())
return 0;
if (link->flags & IFF_LOOPBACK)
return 0;
if (link->network->ipv6_mtu == 0)
return 0;
r = sysctl_write_ip_property_uint32(AF_INET6, link->ifname, "mtu", link->network->ipv6_mtu);
if (r < 0)
return r;
link->ipv6_mtu_set = true;
return 0;
}
static const char* const ipv6_privacy_extensions_table[_IPV6_PRIVACY_EXTENSIONS_MAX] = {
[IPV6_PRIVACY_EXTENSIONS_NO] = "no",
[IPV6_PRIVACY_EXTENSIONS_PREFER_PUBLIC] = "prefer-public",
[IPV6_PRIVACY_EXTENSIONS_YES] = "yes",
};
DEFINE_STRING_TABLE_LOOKUP_WITH_BOOLEAN(ipv6_privacy_extensions, IPv6PrivacyExtensions,
IPV6_PRIVACY_EXTENSIONS_YES);
int config_parse_ipv6_privacy_extensions(
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) {
IPv6PrivacyExtensions s, *ipv6_privacy_extensions = data;
assert(filename);
assert(lvalue);
assert(rvalue);
assert(ipv6_privacy_extensions);
s = ipv6_privacy_extensions_from_string(rvalue);
if (s < 0) {
if (streq(rvalue, "kernel"))
s = _IPV6_PRIVACY_EXTENSIONS_INVALID;
else {
log_syntax(unit, LOG_WARNING, filename, line, 0,
"Failed to parse IPv6 privacy extensions option, ignoring: %s", rvalue);
return 0;
}
}
*ipv6_privacy_extensions = s;
return 0;
}
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