networkd: VXLAN add support to configure IP Don't fragment.

Allow users to set the IPv4 DF bit in outgoing packets, or to inherit its
value from the IPv4 inner header. If the encapsulated protocol is IPv6 and
DF is configured to be inherited, always set it.

3 files changed, 34 insertions, 0 deletions

diff --git a/src/network/netdev/netdev-gperf.gperf b/src/network/netdev/netdev-gperf.gperf
index fe5e53f2a8..e2c994e971 100644
--- a/src/network/netdev/netdev-gperf.gperf
+++ b/src/network/netdev/netdev-gperf.gperf
@@ -124,6 +124,7 @@ VXLAN.MaximumFDBEntries,                  config_parse_unsigned,
 VXLAN.PortRange,                          config_parse_port_range,                   0,                             0
 VXLAN.DestinationPort,                    config_parse_ip_port,                      0,                             offsetof(VxLan, dest_port)
 VXLAN.FlowLabel,                          config_parse_flow_label,                   0,                             0
+VXLAN.IPDoNotFragment,                    config_parse_df,                           0,                             offsetof(VxLan, df)
 GENEVE.Id,                                config_parse_geneve_vni,                   0,                             offsetof(Geneve, id)
 GENEVE.Remote,                            config_parse_geneve_address,               0,                             offsetof(Geneve, remote)
 GENEVE.TOS,                               config_parse_uint8,                        0,                             offsetof(Geneve, tos)
diff --git a/src/network/netdev/vxlan.c b/src/network/netdev/vxlan.c
index 56c97cb686..126f6138a3 100644
--- a/src/network/netdev/vxlan.c
+++ b/src/network/netdev/vxlan.c
@@ -7,6 +7,7 @@
 #include "conf-parser.h"
 #include "alloc-util.h"
 #include "extract-word.h"
+#include "string-table.h"
 #include "string-util.h"
 #include "strv.h"
 #include "parse-util.h"
@@ -15,6 +16,15 @@
 #include "networkd-link.h"
 #include "netdev/vxlan.h"
 
+static const char* const df_table[_NETDEV_VXLAN_DF_MAX] = {
+        [NETDEV_VXLAN_DF_NO] = "no",
+        [NETDEV_VXLAN_DF_YES] = "yes",
+        [NETDEV_VXLAN_DF_INHERIT] = "inherit",
+};
+
+DEFINE_STRING_TABLE_LOOKUP_WITH_BOOLEAN(df, VxLanDF, NETDEV_VXLAN_DF_YES);
+DEFINE_CONFIG_PARSE_ENUM(config_parse_df, df, VxLanDF, "Failed to parse VXLAN IPDoNotFragment= setting");
+
 static int netdev_vxlan_fill_message_create(NetDev *netdev, Link *link, sd_netlink_message *m) {
         VxLan *v;
         int r;
@@ -150,6 +160,12 @@ static int netdev_vxlan_fill_message_create(NetDev *netdev, Link *link, sd_netli
                         return log_netdev_error_errno(netdev, r, "Could not append IFLA_VXLAN_GPE attribute: %m");
         }
 
+        if (v->df != _NETDEV_VXLAN_DF_INVALID) {
+                r = sd_netlink_message_append_u8(m, IFLA_VXLAN_DF, v->df);
+                if (r < 0)
+                        return log_netdev_error_errno(netdev, r, "Could not append IFLA_VXLAN_DF attribute: %m");
+        }
+
         return r;
 }
 
@@ -305,6 +321,7 @@ static void vxlan_init(NetDev *netdev) {
         assert(v);
 
         v->vni = VXLAN_VID_MAX + 1;
+        v->df = _NETDEV_VXLAN_DF_INVALID;
         v->learning = true;
         v->udpcsum = false;
         v->udp6zerocsumtx = false;
diff --git a/src/network/netdev/vxlan.h b/src/network/netdev/vxlan.h
index ad72a10b2f..d448e3ccfe 100644
--- a/src/network/netdev/vxlan.h
+++ b/src/network/netdev/vxlan.h
@@ -3,12 +3,22 @@
 
 typedef struct VxLan VxLan;
 
+#include <linux/if_link.h>
+
 #include "in-addr-util.h"
 #include "netdev/netdev.h"
 
 #define VXLAN_VID_MAX (1u << 24) - 1
 #define VXLAN_FLOW_LABEL_MAX_MASK 0xFFFFFU
 
+typedef enum VxLanDF {
+        NETDEV_VXLAN_DF_NO = VXLAN_DF_UNSET,
+        NETDEV_VXLAN_DF_YES = VXLAN_DF_SET,
+        NETDEV_VXLAN_DF_INHERIT = VXLAN_DF_INHERIT,
+        _NETDEV_VXLAN_DF_MAX,
+        _NETDEV_VXLAN_DF_INVALID = -1
+} VxLanDF;
+
 struct VxLan {
         NetDev meta;
 
@@ -18,6 +28,8 @@ struct VxLan {
         int local_family;
         int group_family;
 
+        VxLanDF df;
+
         union in_addr_union remote;
         union in_addr_union local;
         union in_addr_union group;
@@ -50,6 +62,10 @@ struct VxLan {
 DEFINE_NETDEV_CAST(VXLAN, VxLan);
 extern const NetDevVTable vxlan_vtable;
 
+const char *df_to_string(VxLanDF d) _const_;
+VxLanDF df_from_string(const char *d) _pure_;
+
 CONFIG_PARSER_PROTOTYPE(config_parse_vxlan_address);
 CONFIG_PARSER_PROTOTYPE(config_parse_port_range);
 CONFIG_PARSER_PROTOTYPE(config_parse_flow_label);
+CONFIG_PARSER_PROTOTYPE(config_parse_df);