diff options
Diffstat (limited to 'src/network/networkd-sysctl.c')
| -rw-r--r-- | src/network/networkd-sysctl.c | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/src/network/networkd-sysctl.c b/src/network/networkd-sysctl.c new file mode 100644 index 0000000..2b226b2 --- /dev/null +++ b/src/network/networkd-sysctl.c @@ -0,0 +1,335 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <netinet/in.h> +#include <linux/if.h> +#include <linux/if_arp.h> + +#include "missing_network.h" +#include "networkd-link.h" +#include "networkd-manager.h" +#include "networkd-network.h" +#include "networkd-sysctl.h" +#include "socket-util.h" +#include "string-table.h" +#include "sysctl-util.h" + +static bool link_is_configured_for_family(Link *link, int family) { + assert(link); + + if (!link->network) + return false; + + if (link->flags & IFF_LOOPBACK) + return false; + + /* CAN devices do not support IP layer. Most of the functions below are never called for CAN devices, + * but link_set_ipv6_mtu() may be called after setting interface MTU, and warn about the failure. For + * safety, let's unconditionally check if the interface is not a CAN device. */ + if (IN_SET(family, AF_INET, AF_INET6) && link->iftype == ARPHRD_CAN) + return false; + + if (family == AF_INET6 && !socket_ipv6_is_supported()) + return false; + + return true; +} + +static int link_update_ipv6_sysctl(Link *link) { + assert(link); + + if (!link_is_configured_for_family(link, AF_INET6)) + 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_is_configured_for_family(link, AF_INET)) + 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 (!link_is_configured_for_family(link, family)) + 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_ipv4_rp_filter(Link *link) { + assert(link); + + if (!link_is_configured_for_family(link, AF_INET)) + return 0; + + if (link->network->ipv4_rp_filter < 0) + return 0; + + return sysctl_write_ip_property_int(AF_INET, link->ifname, "rp_filter", link->network->ipv4_rp_filter); +} + +static int link_set_ipv6_privacy_extensions(Link *link) { + IPv6PrivacyExtensions val; + + assert(link); + assert(link->manager); + + if (!link_is_configured_for_family(link, AF_INET6)) + return 0; + + val = link->network->ipv6_privacy_extensions; + if (val < 0) /* If not specified, then use the global setting. */ + val = link->manager->ipv6_privacy_extensions; + + /* When "kernel", do not update the setting. */ + if (val == IPV6_PRIVACY_EXTENSIONS_KERNEL) + return 0; + + return sysctl_write_ip_property_int(AF_INET6, link->ifname, "use_tempaddr", (int) val); +} + +static int link_set_ipv6_accept_ra(Link *link) { + assert(link); + + if (!link_is_configured_for_family(link, AF_INET6)) + 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); + + if (!link_is_configured_for_family(link, AF_INET6)) + 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); + + if (!link_is_configured_for_family(link, AF_INET6)) + 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_ipv6_proxy_ndp(Link *link) { + bool v; + + assert(link); + + if (!link_is_configured_for_family(link, AF_INET6)) + return 0; + + if (link->network->ipv6_proxy_ndp >= 0) + v = link->network->ipv6_proxy_ndp; + else + v = !set_isempty(link->network->ipv6_proxy_ndp_addresses); + + return sysctl_write_ip_property_boolean(AF_INET6, link->ifname, "proxy_ndp", v); +} + +int link_set_ipv6_mtu(Link *link) { + uint32_t mtu; + + assert(link); + + if (!link_is_configured_for_family(link, AF_INET6)) + return 0; + + if (link->network->ipv6_mtu == 0) + return 0; + + mtu = link->network->ipv6_mtu; + if (mtu > link->max_mtu) { + log_link_warning(link, "Reducing requested IPv6 MTU %"PRIu32" to the interface's maximum MTU %"PRIu32".", + mtu, link->max_mtu); + mtu = link->max_mtu; + } + + return sysctl_write_ip_property_uint32(AF_INET6, link->ifname, "mtu", mtu); +} + +static int link_set_ipv4_accept_local(Link *link) { + assert(link); + + if (!link_is_configured_for_family(link, AF_INET)) + 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); +} + +static int link_set_ipv4_route_localnet(Link *link) { + assert(link); + + if (!link_is_configured_for_family(link, AF_INET)) + return 0; + + if (link->network->ipv4_route_localnet < 0) + return 0; + + return sysctl_write_ip_property_boolean(AF_INET, link->ifname, "route_localnet", link->network->ipv4_route_localnet > 0); +} + +static int link_set_ipv4_promote_secondaries(Link *link) { + assert(link); + + if (!link_is_configured_for_family(link, AF_INET)) + return 0; + + /* 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 */ + return sysctl_write_ip_property_boolean(AF_INET, link->ifname, "promote_secondaries", true); +} + +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_ipv6_proxy_ndp(link); + if (r < 0) + log_link_warning_errno(link, r, "Cannot set IPv6 proxy NDP, ignoring: %m"); + + r = link_set_ipv6_mtu(link); + if (r < 0) + log_link_warning_errno(link, r, "Cannot set IPv6 MTU, ignoring: %m"); + + r = link_set_ipv6ll_stable_secret(link); + if (r < 0) + log_link_warning_errno(link, r, "Cannot set stable secret address for IPv6 link-local address: %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"); + + r = link_set_ipv4_route_localnet(link); + if (r < 0) + log_link_warning_errno(link, r, "Cannot set IPv4 route_localnet flag for interface, ignoring: %m"); + + r = link_set_ipv4_rp_filter(link); + if (r < 0) + log_link_warning_errno(link, r, "Cannot set IPv4 reverse path filtering for interface, ignoring: %m"); + + r = link_set_ipv4_promote_secondaries(link); + if (r < 0) + log_link_warning_errno(link, r, "Cannot enable promote_secondaries for interface, ignoring: %m"); + + 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", + [IPV6_PRIVACY_EXTENSIONS_KERNEL] = "kernel", +}; + +DEFINE_STRING_TABLE_LOOKUP_WITH_BOOLEAN(ipv6_privacy_extensions, IPv6PrivacyExtensions, + IPV6_PRIVACY_EXTENSIONS_YES); +DEFINE_CONFIG_PARSE_ENUM(config_parse_ipv6_privacy_extensions, ipv6_privacy_extensions, IPv6PrivacyExtensions, + "Failed to parse IPv6 privacy extensions option"); + +static const char* const ip_reverse_path_filter_table[_IP_REVERSE_PATH_FILTER_MAX] = { + [IP_REVERSE_PATH_FILTER_NO] = "no", + [IP_REVERSE_PATH_FILTER_STRICT] = "strict", + [IP_REVERSE_PATH_FILTER_LOOSE] = "loose", +}; + +DEFINE_STRING_TABLE_LOOKUP(ip_reverse_path_filter, IPReversePathFilter); +DEFINE_CONFIG_PARSE_ENUM(config_parse_ip_reverse_path_filter, ip_reverse_path_filter, IPReversePathFilter, + "Failed to parse IP reverse path filter option"); |