From aaa5ca57ae073bfc72bc77ca797fd23579d1e185 Mon Sep 17 00:00:00 2001 From: Yu Watanabe Date: Sun, 28 Nov 2021 11:51:08 +0900 Subject: [PATCH] network/netdev: make MACAddress= take 'none' to suppress generating persistent hardware address This is mostly equivalent to .link file's MACAddressPolicy=none. --- man/systemd.netdev.xml | 13 +++++++++--- src/network/netdev/netdev-gperf.gperf | 4 ++-- src/network/netdev/netdev.c | 30 ++++++++++++++++++++++++++- src/network/netdev/netdev.h | 4 ++++ src/network/netdev/veth.c | 2 +- 5 files changed, 46 insertions(+), 7 deletions(-) diff --git a/man/systemd.netdev.xml b/man/systemd.netdev.xml index 9cbd99a0efc..133c6fcc637 100644 --- a/man/systemd.netdev.xml +++ b/man/systemd.netdev.xml @@ -254,9 +254,12 @@ MACAddress= - The MAC address to use for the device. For tun or tap - devices, setting MACAddress= in the [NetDev] section is not - supported. Please specify it in the [Link] section of the corresponding + Specifies the MAC address to use for the device, or takes the special value + none. When none, systemd-networkd + does not request the MAC address for the device, and the kernel will assign a random MAC + address. For tun, tap, or l2tp + devices, the MACAddress= setting in the [NetDev] section is not + supported and will be ignored. Please specify it in the [Link] section of the corresponding systemd.network5 file. If this option is not set, bridge and vlan devices inherit the MAC address of the first slave device or the physical interface, respectively. For other @@ -264,6 +267,10 @@ name and the machine-id5. + Note, even if none is specified, systemd-udevd + will assign the persistent MAC address for the device, as 99-default.link + has MACAddressPolicy=persistent. So, it is also necessary to create a + custom .link file for the device, if the MAC address assignment is not desired. diff --git a/src/network/netdev/netdev-gperf.gperf b/src/network/netdev/netdev-gperf.gperf index d0f493b4ef5..316592005f2 100644 --- a/src/network/netdev/netdev-gperf.gperf +++ b/src/network/netdev/netdev-gperf.gperf @@ -49,7 +49,7 @@ NetDev.Description, config_parse_string, NetDev.Name, config_parse_ifname, 0, offsetof(NetDev, ifname) NetDev.Kind, config_parse_netdev_kind, 0, offsetof(NetDev, kind) NetDev.MTUBytes, config_parse_mtu, AF_UNSPEC, offsetof(NetDev, mtu) -NetDev.MACAddress, config_parse_hw_addr, ETH_ALEN, offsetof(NetDev, hw_addr) +NetDev.MACAddress, config_parse_netdev_hw_addr, ETH_ALEN, offsetof(NetDev, hw_addr) VLAN.Id, config_parse_vlanid, 0, offsetof(VLan, id) VLAN.Protocol, config_parse_vlanprotocol, 0, offsetof(VLan, protocol) VLAN.GVRP, config_parse_tristate, 0, offsetof(VLan, gvrp) @@ -111,7 +111,7 @@ L2TPSession.PeerSessionId, config_parse_l2tp_session_id, L2TPSession.Layer2SpecificHeader, config_parse_l2tp_session_l2spec, 0, 0 L2TPSession.Name, config_parse_l2tp_session_name, 0, 0 Peer.Name, config_parse_ifname, 0, offsetof(Veth, ifname_peer) -Peer.MACAddress, config_parse_hw_addr, ETH_ALEN, offsetof(Veth, hw_addr_peer) +Peer.MACAddress, config_parse_netdev_hw_addr, ETH_ALEN, offsetof(Veth, hw_addr_peer) VXCAN.Peer, config_parse_ifname, 0, offsetof(VxCan, ifname_peer) VXLAN.VNI, config_parse_uint32, 0, offsetof(VxLan, vni) VXLAN.Id, config_parse_uint32, 0, offsetof(VxLan, vni) /* deprecated */ diff --git a/src/network/netdev/netdev.c b/src/network/netdev/netdev.c index 4d0f2e14eb7..5d88cbdf5f1 100644 --- a/src/network/netdev/netdev.c +++ b/src/network/netdev/netdev.c @@ -400,6 +400,9 @@ int netdev_generate_hw_addr(NetDev *netdev, const char *name, struct hw_addr_dat assert(name); assert(hw_addr); + if (hw_addr_equal(hw_addr, &HW_ADDR_NONE)) + return 0; + if (hw_addr->length == 0) { uint64_t result; @@ -467,7 +470,7 @@ static int netdev_create(NetDev *netdev, Link *link, link_netlink_message_handle if (r < 0) return log_netdev_error_errno(netdev, r, "Could not append IFLA_IFNAME, attribute: %m"); - if (netdev->hw_addr.length > 0) { + if (netdev->hw_addr.length > 0 && !hw_addr_equal(&netdev->hw_addr, &HW_ADDR_NULL)) { r = netlink_message_append_hw_addr(m, IFLA_ADDRESS, &netdev->hw_addr); if (r < 0) return log_netdev_error_errno(netdev, r, "Could not append IFLA_ADDRESS attribute: %m"); @@ -887,3 +890,28 @@ int config_parse_netdev_kind( return 0; } + +int config_parse_netdev_hw_addr( + 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) { + + struct hw_addr_data *hw_addr = data; + + assert(rvalue); + assert(data); + + if (streq(rvalue, "none")) { + *hw_addr = HW_ADDR_NONE; + return 0; + } + + return config_parse_hw_addr(unit, filename, line, section, section_line, lvalue, ltype, rvalue, data, userdata); +} diff --git a/src/network/netdev/netdev.h b/src/network/netdev/netdev.h index d480d125a69..ed8a2e33c51 100644 --- a/src/network/netdev/netdev.h +++ b/src/network/netdev/netdev.h @@ -10,6 +10,9 @@ #include "networkd-link.h" #include "time-util.h" +/* Special hardware address value to suppress generating persistent hardware address for the netdev. */ +#define HW_ADDR_NONE ((struct hw_addr_data) { .length = 1, }) + #define NETDEV_COMMON_SECTIONS "Match\0NetDev\0" /* This is the list of known sections. We need to ignore them in the initial parsing phase. */ #define NETDEV_OTHER_SECTIONS \ @@ -215,6 +218,7 @@ static inline NetDevCreateType netdev_get_create_type(NetDev *netdev) { } CONFIG_PARSER_PROTOTYPE(config_parse_netdev_kind); +CONFIG_PARSER_PROTOTYPE(config_parse_netdev_hw_addr); /* gperf */ const struct ConfigPerfItem* network_netdev_gperf_lookup(const char *key, GPERF_LEN_TYPE length); diff --git a/src/network/netdev/veth.c b/src/network/netdev/veth.c index f1c05c62052..d7870d7628a 100644 --- a/src/network/netdev/veth.c +++ b/src/network/netdev/veth.c @@ -31,7 +31,7 @@ static int netdev_veth_fill_message_create(NetDev *netdev, Link *link, sd_netlin return log_netdev_error_errno(netdev, r, "Failed to add netlink interface name: %m"); } - if (v->hw_addr_peer.length > 0) { + if (v->hw_addr_peer.length > 0 && !hw_addr_equal(&v->hw_addr_peer, &HW_ADDR_NULL)) { r = netlink_message_append_hw_addr(m, IFLA_ADDRESS, &v->hw_addr_peer); if (r < 0) return log_netdev_error_errno(netdev, r, "Could not append IFLA_ADDRESS attribute: %m");