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, 5 insertions, 2 deletions

diff --git a/src/network/networkd-link.h b/src/network/networkd-link.h
index 5efefd27d6..7db94e79e8 100644
--- a/src/network/networkd-link.h
+++ b/src/network/networkd-link.h
@@ -98,6 +98,7 @@ typedef struct Link {
         unsigned dhcp4_messages;
         bool dhcp4_configured;
         bool dhcp6_configured;
+
         unsigned ndisc_messages;
         bool ndisc_configured;
 
@@ -111,7 +112,10 @@ typedef struct Link {
 
         sd_dhcp_server *dhcp_server;
 
-        sd_ndisc *ndisc_router_discovery;
+        sd_ndisc *ndisc;
+        Set *ndisc_rdnss;
+        Set *ndisc_dnssl;
+
         sd_dhcp6_client *dhcp6_client;
         bool rtnl_extended_attrs;
 
@@ -161,7 +165,6 @@ int ipv4ll_configure(Link *link);
 int dhcp4_configure(Link *link);
 int dhcp6_configure(Link *link);
 int dhcp6_request_address(Link *link, int ir);
-int ndisc_configure(Link *link);
 
 const char* link_state_to_string(LinkState s) _const_;
 LinkState link_state_from_string(const char *s) _pure_;