/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include #include #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; }