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, 80 insertions, 34 deletions

diff --git a/src/systemd/sd-ndisc.h b/src/systemd/sd-ndisc.h
index 2b774233b8..9f7d4ef71a 100644
--- a/src/systemd/sd-ndisc.h
+++ b/src/systemd/sd-ndisc.h
@@ -22,6 +22,8 @@
 
 #include <inttypes.h>
 #include <net/ethernet.h>
+#include <netinet/in.h>
+#include <sys/types.h>
 
 #include "sd-event.h"
 
@@ -29,55 +31,99 @@
 
 _SD_BEGIN_DECLARATIONS;
 
+/* Neightbor Discovery Options, RFC 4861, Section 4.6 and
+ * https://www.iana.org/assignments/icmpv6-parameters/icmpv6-parameters.xhtml#icmpv6-parameters-5 */
 enum {
-        SD_NDISC_EVENT_STOP     = 0,
-        SD_NDISC_EVENT_TIMEOUT  = 1,
+        SD_NDISC_OPTION_SOURCE_LL_ADDRESS  = 1,
+        SD_NDISC_OPTION_TARGET_LL_ADDRESS  = 2,
+        SD_NDISC_OPTION_PREFIX_INFORMATION = 3,
+        SD_NDISC_OPTION_MTU                = 5,
+        SD_NDISC_OPTION_ROUTE_INFORMATION  = 24,
+        SD_NDISC_OPTION_RDNSS              = 25,
+        SD_NDISC_OPTION_FLAGS_EXTENSION    = 26,
+        SD_NDISC_OPTION_DNSSL              = 31,
+        SD_NDISC_OPTION_CAPTIVE_PORTAL     = 37,
+};
+
+/* Route preference, RFC 4191, Section 2.1 */
+enum {
+        SD_NDISC_PREFERENCE_LOW    = 3U,
+        SD_NDISC_PREFERENCE_MEDIUM = 0U,
+        SD_NDISC_PREFERENCE_HIGH   = 1U,
 };
 
 typedef struct sd_ndisc sd_ndisc;
+typedef struct sd_ndisc_router sd_ndisc_router;
 
-typedef void(*sd_ndisc_router_callback_t)(sd_ndisc *nd, uint8_t flags, const struct in6_addr *gateway, unsigned lifetime, int pref, void *userdata);
-typedef void(*sd_ndisc_prefix_onlink_callback_t)(sd_ndisc *nd, const struct in6_addr *prefix, unsigned prefixlen,
-                                                 unsigned lifetime, void *userdata);
-typedef void(*sd_ndisc_prefix_autonomous_callback_t)(sd_ndisc *nd, const struct in6_addr *prefix, unsigned prefixlen,
-                                                     unsigned lifetime_prefered, unsigned lifetime_valid, void *userdata);
-typedef void(*sd_ndisc_callback_t)(sd_ndisc *nd, int event, void *userdata);
-
-int sd_ndisc_set_callback(sd_ndisc *nd,
-                          sd_ndisc_router_callback_t rcb,
-                          sd_ndisc_prefix_onlink_callback_t plcb,
-                          sd_ndisc_prefix_autonomous_callback_t pacb,
-                          sd_ndisc_callback_t cb,
-                          void *userdata);
-int sd_ndisc_set_ifindex(sd_ndisc *nd, int interface_index);
-int sd_ndisc_set_mac(sd_ndisc *nd, const struct ether_addr *mac_addr);
+typedef enum sd_ndisc_event {
+        SD_NDISC_EVENT_TIMEOUT = 't',
+        SD_NDISC_EVENT_ROUTER  = 'r',
+} sd_ndisc_event;
 
-int sd_ndisc_attach_event(sd_ndisc *nd, sd_event *event, int64_t priority);
-int sd_ndisc_detach_event(sd_ndisc *nd);
-sd_event *sd_ndisc_get_event(sd_ndisc *nd);
+typedef void (*sd_ndisc_callback_t)(sd_ndisc *nd, sd_ndisc_event event, sd_ndisc_router *rt, void *userdata);
 
+int sd_ndisc_new(sd_ndisc **ret);
 sd_ndisc *sd_ndisc_ref(sd_ndisc *nd);
 sd_ndisc *sd_ndisc_unref(sd_ndisc *nd);
-int sd_ndisc_new(sd_ndisc **ret);
-
-int sd_ndisc_get_mtu(sd_ndisc *nd, uint32_t *mtu);
 
+int sd_ndisc_start(sd_ndisc *nd);
 int sd_ndisc_stop(sd_ndisc *nd);
-int sd_ndisc_router_discovery_start(sd_ndisc *nd);
 
-#define SD_NDISC_ADDRESS_FORMAT_STR "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x"
+int sd_ndisc_attach_event(sd_ndisc *nd, sd_event *event, int64_t priority);
+int sd_ndisc_detach_event(sd_ndisc *nd);
+sd_event *sd_ndisc_get_event(sd_ndisc *nd);
+
+int sd_ndisc_set_callback(sd_ndisc *nd, sd_ndisc_callback_t cb, void *userdata);
+int sd_ndisc_set_ifindex(sd_ndisc *nd, int interface_index);
+int sd_ndisc_set_mac(sd_ndisc *nd, const struct ether_addr *mac_addr);
 
-#define SD_NDISC_ADDRESS_FORMAT_VAL(address) \
-        be16toh((address).s6_addr16[0]),        \
-        be16toh((address).s6_addr16[1]),        \
-        be16toh((address).s6_addr16[2]),        \
-        be16toh((address).s6_addr16[3]),        \
-        be16toh((address).s6_addr16[4]),        \
-        be16toh((address).s6_addr16[5]),        \
-        be16toh((address).s6_addr16[6]),        \
-        be16toh((address).s6_addr16[7])
+int sd_ndisc_get_mtu(sd_ndisc *nd, uint32_t *ret);
+int sd_ndisc_get_hop_limit(sd_ndisc *nd, uint8_t *ret);
+
+int sd_ndisc_router_from_raw(sd_ndisc_router **ret, const void *raw, size_t raw_size);
+sd_ndisc_router *sd_ndisc_router_ref(sd_ndisc_router *rt);
+sd_ndisc_router *sd_ndisc_router_unref(sd_ndisc_router *rt);
+
+int sd_ndisc_router_get_address(sd_ndisc_router *rt, struct in6_addr *ret_addr);
+int sd_ndisc_router_get_timestamp(sd_ndisc_router *rt, clockid_t clock, uint64_t *ret);
+int sd_ndisc_router_get_raw(sd_ndisc_router *rt, const void **ret, size_t *size);
+
+int sd_ndisc_router_get_hop_limit(sd_ndisc_router *rt, uint8_t *ret);
+int sd_ndisc_router_get_flags(sd_ndisc_router *rt, uint64_t *ret_flags);
+int sd_ndisc_router_get_preference(sd_ndisc_router *rt, unsigned *ret);
+int sd_ndisc_router_get_lifetime(sd_ndisc_router *rt, uint16_t *ret_lifetime);
+int sd_ndisc_router_get_mtu(sd_ndisc_router *rt, uint32_t *ret);
+
+/* Generic option access */
+int sd_ndisc_router_option_rewind(sd_ndisc_router *rt);
+int sd_ndisc_router_option_next(sd_ndisc_router *rt);
+int sd_ndisc_router_option_get_type(sd_ndisc_router *rt, uint8_t *ret);
+int sd_ndisc_router_option_is_type(sd_ndisc_router *rt, uint8_t type);
+int sd_ndisc_router_option_get_raw(sd_ndisc_router *rt, const void **ret, size_t *size);
+
+/* Specific option access: SD_NDISC_OPTION_PREFIX_INFORMATION */
+int sd_ndisc_router_prefix_get_valid_lifetime(sd_ndisc_router *rt, uint32_t *ret);
+int sd_ndisc_router_prefix_get_preferred_lifetime(sd_ndisc_router *rt, uint32_t *ret);
+int sd_ndisc_router_prefix_get_flags(sd_ndisc_router *rt, uint8_t *ret);
+int sd_ndisc_router_prefix_get_address(sd_ndisc_router *rt, struct in6_addr *ret_addr);
+int sd_ndisc_router_prefix_get_prefixlen(sd_ndisc_router *rt, unsigned *prefixlen);
+
+/* Specific option access: SD_NDISC_OPTION_ROUTE_INFORMATION */
+int sd_ndisc_router_route_get_lifetime(sd_ndisc_router *rt, uint32_t *ret);
+int sd_ndisc_router_route_get_address(sd_ndisc_router *rt, struct in6_addr *ret_addr);
+int sd_ndisc_router_route_get_prefixlen(sd_ndisc_router *rt, unsigned *prefixlen);
+int sd_ndisc_router_route_get_preference(sd_ndisc_router *rt, unsigned *ret);
+
+/* Specific option access: SD_NDISC_OPTION_RDNSS */
+int sd_ndisc_router_rdnss_get_addresses(sd_ndisc_router *rt, const struct in6_addr **ret);
+int sd_ndisc_router_rdnss_get_lifetime(sd_ndisc_router *rt, uint32_t *ret);
+
+/* Specific option access: SD_NDISC_OPTION_DNSSL */
+int sd_ndisc_router_dnssl_get_domains(sd_ndisc_router *rt, char ***ret);
+int sd_ndisc_router_dnssl_get_lifetime(sd_ndisc_router *rt, uint32_t *ret);
 
 _SD_DEFINE_POINTER_CLEANUP_FUNC(sd_ndisc, sd_ndisc_unref);
+_SD_DEFINE_POINTER_CLEANUP_FUNC(sd_ndisc_router, sd_ndisc_router_unref);
 
 _SD_END_DECLARATIONS;