networkd: add support for address label

IPv6 address labels are used for address selection; they are described in RFC 3484.
Precedence is managed by userspace, and only the label itself is stored in the kernel.

enp0s25.network

[Match]
Name=enp0s25

[Network]
DHCP=yes
Address = 2001:db8:f00:baa::b

[AddressLabel]
Label=199
Prefix=2001:db8:41::/64

[AddressLabel]
Label=11
Prefix=2001:db8:31::/64

[AddressLabel]
Label=123
Prefix=2001:db8:21::/64

[AddressLabel]
Label=124
Prefix=2001:db8:11::/64
[sus@maximus label]$ ip addrlabel list

prefix ::1/128 label 0
prefix ::/96 label 3
prefix ::ffff:0.0.0.0/96 label 4
prefix 2001:db8:41::/64 dev enp0s25 label 199
prefix 2001:db8:31::/64 dev enp0s25 label 11
prefix 2001:db8:21::/64 dev enp0s25 label 123
prefix 2001:db8:11::/64 dev enp0s25 label 124
prefix 2001::/32 label 6
prefix 2001:10::/28 label 7
prefix 3ffe::/16 label 12
prefix 2002::/16 label 2
prefix fec0::/10 label 11
prefix fc00::/7 label 5
prefix ::/0 label 1

1 files changed, 59 insertions, 0 deletions

diff --git a/src/network/networkd-address-label.h b/src/network/networkd-address-label.h
new file mode 100644
index 0000000000..05bb24924c
--- /dev/null
+++ b/src/network/networkd-address-label.h
@@ -0,0 +1,59 @@
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2017 Susant Sahani
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <inttypes.h>
+#include <stdbool.h>
+
+#include "in-addr-util.h"
+
+typedef struct AddressLabel AddressLabel;
+
+#include "networkd-link.h"
+#include "networkd-network.h"
+
+typedef struct Network Network;
+typedef struct Link Link;
+typedef struct NetworkConfigSection NetworkConfigSection;
+
+struct AddressLabel {
+        Network *network;
+        Link *link;
+        NetworkConfigSection *section;
+
+        int family;
+        unsigned char prefixlen;
+        uint32_t label;
+
+        union in_addr_union in_addr;
+
+        LIST_FIELDS(AddressLabel, labels);
+};
+
+int address_label_new(AddressLabel **ret);
+void address_label_free(AddressLabel *label);
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(AddressLabel*, address_label_free);
+#define _cleanup_address_label_free_ _cleanup_(address_label_freep)
+
+int address_label_configure(AddressLabel *address, Link *link, sd_netlink_message_handler_t callback, bool update);
+
+int config_parse_address_label(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_address_label_prefix(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);