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, 46 insertions, 15 deletions

diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c
index 90ed55d42c..11628339b9 100644
--- a/src/network/networkd-link.c
+++ b/src/network/networkd-link.c
@@ -28,8 +28,9 @@
 #include "fileio.h"
 #include "netlink-util.h"
 #include "network-internal.h"
-#include "networkd.h"
 #include "networkd-lldp-tx.h"
+#include "networkd-ndisc.h"
+#include "networkd.h"
 #include "set.h"
 #include "socket-util.h"
 #include "stdio-util.h"
@@ -504,7 +505,10 @@ static void link_free(Link *link) {
 
         sd_ipv4ll_unref(link->ipv4ll);
         sd_dhcp6_client_unref(link->dhcp6_client);
-        sd_ndisc_unref(link->ndisc_router_discovery);
+        sd_ndisc_unref(link->ndisc);
+
+        set_free_free(link->ndisc_rdnss);
+        set_free_free(link->ndisc_dnssl);
 
         if (link->manager)
                 hashmap_remove(link->manager->links, INT_TO_PTR(link->ifindex));
@@ -616,8 +620,8 @@ static int link_stop_clients(Link *link) {
                         r = log_link_warning_errno(link, k, "Could not stop DHCPv6 client: %m");
         }
 
-        if (link->ndisc_router_discovery) {
-                k = sd_ndisc_stop(link->ndisc_router_discovery);
+        if (link->ndisc) {
+                k = sd_ndisc_stop(link->ndisc);
                 if (k < 0)
                         r = log_link_warning_errno(link, k, "Could not stop IPv6 Router Discovery: %m");
         }
@@ -1453,11 +1457,11 @@ static int link_acquire_ipv6_conf(Link *link) {
         }
 
         if (link_ipv6_accept_ra_enabled(link)) {
-                assert(link->ndisc_router_discovery);
+                assert(link->ndisc);
 
                 log_link_debug(link, "Discovering IPv6 routers");
 
-                r = sd_ndisc_router_discovery_start(link->ndisc_router_discovery);
+                r = sd_ndisc_start(link->ndisc);
                 if (r < 0 && r != -EBUSY)
                         return log_link_warning_errno(link, r, "Could not start IPv6 Router Discovery: %m");
         }
@@ -3087,6 +3091,22 @@ int link_save(Link *link) {
                                 if (space)
                                         fputc(' ', f);
                                 serialize_in6_addrs(f, in6_addrs, r);
+                                space = true;
+                        }
+                }
+
+                /* Make sure to flush out old entries before we use the NDISC data */
+                ndisc_vacuum(link);
+
+                if (link->network->dhcp_use_dns && link->ndisc_rdnss) {
+                        NDiscRDNSS *dd;
+
+                        SET_FOREACH(dd, link->ndisc_rdnss, i) {
+                                if (space)
+                                        fputc(' ', f);
+
+                                serialize_in6_addrs(f, &dd->address, 1);
+                                space = true;
                         }
                 }
 
@@ -3132,7 +3152,6 @@ int link_save(Link *link) {
                 if (link->network->dhcp_use_domains != DHCP_USE_DOMAINS_NO) {
                         if (link->dhcp_lease)
                                 (void) sd_dhcp_lease_get_domainname(link->dhcp_lease, &dhcp_domainname);
-
                         if (dhcp6_lease)
                                 (void) sd_dhcp6_lease_get_domains(dhcp6_lease, &dhcp6_domains);
                 }
@@ -3140,22 +3159,34 @@ int link_save(Link *link) {
                 fputs("DOMAINS=", f);
                 fputstrv(f, link->network->search_domains, NULL, &space);
 
-                if (link->network->dhcp_use_domains == DHCP_USE_DOMAINS_YES && dhcp_domainname)
-                        fputs_with_space(f, dhcp_domainname, NULL, &space);
+                if (link->network->dhcp_use_domains == DHCP_USE_DOMAINS_YES) {
+                        NDiscDNSSL *dd;
 
-                if (link->network->dhcp_use_domains == DHCP_USE_DOMAINS_YES && dhcp6_domains)
-                        fputstrv(f, dhcp6_domains, NULL, &space);
+                        if (dhcp_domainname)
+                                fputs_with_space(f, dhcp_domainname, NULL, &space);
+                        if (dhcp6_domains)
+                                fputstrv(f, dhcp6_domains, NULL, &space);
+
+                        SET_FOREACH(dd, link->ndisc_dnssl, i)
+                                fputs_with_space(f, NDISC_DNSSL_DOMAIN(dd), NULL, &space);
+                }
 
                 fputc('\n', f);
 
                 fputs("ROUTE_DOMAINS=", f);
                 fputstrv(f, link->network->route_domains, NULL, NULL);
 
-                if (link->network->dhcp_use_domains == DHCP_USE_DOMAINS_ROUTE && dhcp_domainname)
-                        fputs_with_space(f, dhcp_domainname, NULL, &space);
+                if (link->network->dhcp_use_domains == DHCP_USE_DOMAINS_ROUTE) {
+                        NDiscDNSSL *dd;
 
-                if (link->network->dhcp_use_domains == DHCP_USE_DOMAINS_ROUTE && dhcp6_domains)
-                        fputstrv(f, dhcp6_domains, NULL, &space);
+                        if (dhcp_domainname)
+                                fputs_with_space(f, dhcp_domainname, NULL, &space);
+                        if (dhcp6_domains)
+                                fputstrv(f, dhcp6_domains, NULL, &space);
+
+                        SET_FOREACH(dd, link->ndisc_dnssl, i)
+                                fputs_with_space(f, NDISC_DNSSL_DOMAIN(dd), NULL, &space);
+                }
 
                 fputc('\n', f);