network: beef up ipv6 RA support considerably

This reworks sd-ndisc and networkd substantially to support IPv6 RA much more
comprehensively. Since the API is extended quite a bit networkd has been ported
over too, and the patch is not as straight-forward as one could wish. The
rework includes:

- Support for DNSSL, RDNSS and RA routing options in sd-ndisc and networkd. Two
  new configuration options have been added to networkd to make this
  configurable.

- sd-ndisc now exposes an sd_ndisc_router object that encapsulates a full RA
  message, and has direct, friendly acessor functions for the singleton RA
  properties, as well as an iterative interface to iterate through known and
  unsupported options. The router object may either be retrieved from the wire,
  or generated from raw data. In many ways the sd-ndisc API now matches the
  sd-lldp API, except that no implicit database of seen data is kept. (Note
  that sd-ndisc actually had a half-written, but unused implementaiton of such
  a store, which is removed now.)

- sd-ndisc will now collect the reception timestamps of RA, which is useful to
  make sd_ndisc_router fully descriptive of what it covers.

Fixes: #1079

1 files changed, 39 insertions, 0 deletions

diff --git a/src/network/networkd-ndisc.h b/src/network/networkd-ndisc.h
new file mode 100644
index 0000000000..2002f55107
--- /dev/null
+++ b/src/network/networkd-ndisc.h
@@ -0,0 +1,39 @@
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Tom Gundersen <teg@jklm.no>
+
+  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 "networkd-link.h"
+
+typedef struct NDiscRDNSS {
+        usec_t valid_until;
+        struct in6_addr address;
+} NDiscRDNSS;
+
+typedef struct NDiscDNSSL {
+        usec_t valid_until;
+        /* The domain name follows immediately. */
+} NDiscDNSSL;
+
+static inline char* NDISC_DNSSL_DOMAIN(const NDiscDNSSL *n) {
+        return ((char*) n) + ALIGN(sizeof(NDiscDNSSL));
+}
+
+int ndisc_configure(Link *link);
+void ndisc_vacuum(Link *link);