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-rw-r--r--man/systemd.network.xml11
-rw-r--r--src/basic/missing.h4
-rw-r--r--src/network/networkd-link.c50
-rw-r--r--src/network/networkd-network.c13
-rw-r--r--src/network/networkd-network.h2
5 files changed, 79 insertions, 1 deletions
diff --git a/man/systemd.network.xml b/man/systemd.network.xml
index d7947836e9..8ae384185d 100644
--- a/man/systemd.network.xml
+++ b/man/systemd.network.xml
@@ -202,6 +202,8 @@
<para>The maximum transmission unit in bytes to set for the
device. The usual suffixes K, M, G, are supported and are
understood to the base of 1024.</para>
+ <para>Note that if IPv6 is enabled on the interface, and the MTU is chosen
+ below 1280 (the minimum MTU for IPv6) it will automatically be increased to this value.</para>
</listitem>
</varlistentry>
<varlistentry>
@@ -210,6 +212,15 @@
<para>Identity Association Identifier for the interface, a 32-bit unsigned integer.</para>
</listitem>
</varlistentry>
+ <varlistentry>
+ <listitem>
+ <para>Note that an interface without any static IPv6 addresses configured, and neither
+ DHCPv6 nor IPv6LL enabled, shall be considered to have no IPv6 support. IPv6 will be
+ automatically disabled for that interface by writing "1" to
+ <filename>/proc/sys/net/ipv6/conf/<replaceable>ifname</replaceable>/disable_ipv6.</filename>
+ </para>
+ </listitem>
+ </varlistentry>
</variablelist>
</refsect1>
diff --git a/src/basic/missing.h b/src/basic/missing.h
index 6a49ccd281..6616f0b720 100644
--- a/src/basic/missing.h
+++ b/src/basic/missing.h
@@ -828,6 +828,10 @@ struct btrfs_ioctl_quota_ctl_args {
#define IPV6_UNICAST_IF 76
#endif
+#ifndef IPV6_MIN_MTU
+#define IPV6_MIN_MTU 1280
+#endif
+
#ifndef IFF_MULTI_QUEUE
#define IFF_MULTI_QUEUE 0x100
#endif
diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c
index 9059a68fe3..0fb3aa6c43 100644
--- a/src/network/networkd-link.c
+++ b/src/network/networkd-link.c
@@ -99,6 +99,15 @@ static bool link_ipv6ll_enabled(Link *link) {
return link->network->link_local & ADDRESS_FAMILY_IPV6;
}
+static bool link_ipv6_enabled(Link *link) {
+ assert(link);
+
+ if (!socket_ipv6_is_supported())
+ return false;
+
+ return link_dhcp6_enabled(link) || link_ipv6ll_enabled(link) || network_has_static_ipv6_addresses(link->network);
+}
+
static bool link_lldp_rx_enabled(Link *link) {
assert(link);
@@ -218,6 +227,31 @@ static IPv6PrivacyExtensions link_ipv6_privacy_extensions(Link *link) {
return link->network->ipv6_privacy_extensions;
}
+static int link_enable_ipv6(Link *link) {
+ const char *p = NULL;
+ bool disabled;
+ int r;
+
+ if (link->flags & IFF_LOOPBACK)
+ return 0;
+
+ disabled = !link_ipv6_enabled(link);
+
+ p = strjoina("/proc/sys/net/ipv6/conf/", link->ifname, "/disable_ipv6");
+
+ r = write_string_file(p, one_zero(disabled), WRITE_STRING_FILE_VERIFY_ON_FAILURE);
+ if (r < 0)
+ log_link_warning_errno(link, r, "Cannot %s IPv6 for interface %s: %m", disabled ? "disable" : "enable", link->ifname);
+ else {
+ if (disabled)
+ log_link_info(link, "IPv6 disabled for interface: %m");
+ else
+ log_link_info(link, "IPv6 enabled for interface: %m");
+ }
+
+ return 0;
+}
+
void link_update_operstate(Link *link) {
LinkOperationalState operstate;
assert(link);
@@ -1510,7 +1544,21 @@ static int link_up(Link *link) {
return log_link_error_errno(link, r, "Could not set MAC address: %m");
}
+ /* If IPv6 not configured (no static IPv6 address and neither DHCPv6 nor IPv6LL is enabled)
+ for this interface then disable IPv6 else enable it. */
+ (void) link_enable_ipv6(link);
+
if (link->network->mtu) {
+ /* IPv6 protocol requires a minimum MTU of IPV6_MTU_MIN(1280) bytes
+ on the interface. Bump up MTU bytes to IPV6_MTU_MIN. */
+ if (link_ipv6_enabled(link) && link->network->mtu < IPV6_MIN_MTU) {
+
+ log_link_warning(link, "Bumping MTU to " STRINGIFY(IPV6_MIN_MTU) ", as "
+ "IPv6 is requested and requires a minimum MTU of " STRINGIFY(IPV6_MIN_MTU) " bytes: %m");
+
+ link->network->mtu = IPV6_MIN_MTU;
+ }
+
r = sd_netlink_message_append_u32(req, IFLA_MTU, link->network->mtu);
if (r < 0)
return log_link_error_errno(link, r, "Could not set MTU: %m");
@@ -1520,7 +1568,7 @@ static int link_up(Link *link) {
if (r < 0)
return log_link_error_errno(link, r, "Could not open IFLA_AF_SPEC container: %m");
- if (socket_ipv6_is_supported()) {
+ if (link_ipv6_enabled(link)) {
/* if the kernel lacks ipv6 support setting IFF_UP fails if any ipv6 options are passed */
r = sd_netlink_message_open_container(req, AF_INET6);
if (r < 0)
diff --git a/src/network/networkd-network.c b/src/network/networkd-network.c
index 1c7adf5180..07f8fb028f 100644
--- a/src/network/networkd-network.c
+++ b/src/network/networkd-network.c
@@ -399,6 +399,19 @@ int network_apply(Manager *manager, Network *network, Link *link) {
return 0;
}
+bool network_has_static_ipv6_addresses(Network *network) {
+ Address *address;
+
+ assert(network);
+
+ LIST_FOREACH(addresses, address, network->static_addresses) {
+ if (address->family == AF_INET6)
+ return true;
+ }
+
+ return false;
+}
+
int config_parse_netdev(const char *unit,
const char *filename,
unsigned line,
diff --git a/src/network/networkd-network.h b/src/network/networkd-network.h
index 3d44113b05..15417f4828 100644
--- a/src/network/networkd-network.h
+++ b/src/network/networkd-network.h
@@ -186,6 +186,8 @@ int network_get_by_name(Manager *manager, const char *name, Network **ret);
int network_get(Manager *manager, struct udev_device *device, const char *ifname, const struct ether_addr *mac, Network **ret);
int network_apply(Manager *manager, Network *network, Link *link);
+bool network_has_static_ipv6_addresses(Network *network);
+
int config_parse_netdev(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_domains(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_tunnel(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);
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-01 14:45:59 +0000