sd-lldp: rework sd-lldp API

This reworks the sd-lldp substantially, simplifying things on one hand, and
extending the logic a bit on the other.

Specifically:

- Besides the sd_lldp object only one other object is maintained now,
  sd_lldp_neighbor. It's used both as storage for literal LLDP packets, and for
  maintainging info about peers in the database. Separation between packet, TLV
  and chassis data is not maintained anymore. This should be a major
  simplification.

- The sd-lldp API has been extended so that a couple of per-neighbor fields may
  be queried directly, without iterating through the object. Other fields that
  may appear multiple times, OTOH have to be iterated through.

- The maximum number of entries in the neighbor database is now configurable
  during runtime.

- The generation of callbacks from sd_lldp objects is more restricted:
  callbacks are only invoked when actual data changed.

- The TTL information is now hooked with a timer event, so that removals from
  the neighbor database due to TTLs now result in a callback event.

- Querying LLDP neighbor database will now return a strictly ordered array, to
  guarantee stability.

- A "capabilities" mask may now be configured, that selects what type of LLDP
  neighbor data is collected. This may be used to restrict collection of LLDP
  info about routers instead of all neighbors. This is now exposed via
  networkd's LLDP= setting.

- sd-lldp's API to serialize the collected data to text files has been removed.
  Instead, there's now an API to extract the raw binary data from LLDP neighbor
  objects, as well as one to convert this raw binary data back to an LLDP
  neighbor object. networkd will save this raw binary data to /run now, and the
  client side can simply parse the information.

- support for parsing the more exotic TLVs has been removed, since we are not
  using that. Instead there are now APIs to extract the raw data from TLVs.
  Given how easy it is to parse the TLVs clients should do so now directly
  instead of relying on our APIs for that.

- A lot of the APIs that parse out LLDP strings have been simplified so that
  they actually return strings, instead of char arrays with a length. To deal
  with possibly dangerous characters the strings are escaped if needed.

- APIs to extract and format the chassis and port IDs as strings has been
  added.

- lldp.h has been simplified a lot. The enums are anonymous now, since they
  were never used as enums, but simply as constants. Most definitions we don't
  actually use ourselves have eben removed.

2 files changed, 40 insertions, 38 deletions

diff --git a/src/systemd/sd-lldp.h b/src/systemd/sd-lldp.h
index 4c896e7fc0..11b89258ed 100644
--- a/src/systemd/sd-lldp.h
+++ b/src/systemd/sd-lldp.h
@@ -30,22 +30,12 @@
 
 _SD_BEGIN_DECLARATIONS;
 
-enum {
-        SD_LLDP_EVENT_UPDATE_INFO       = 0,
-};
-
-enum {
-        SD_LLDP_DESTINATION_TYPE_NEAREST_BRIDGE,
-        SD_LLDP_DESTINATION_TYPE_NEAREST_NON_TPMR_BRIDGE,
-        SD_LLDP_DESTINATION_TYPE_NEAREST_CUSTOMER_BRIDGE,
-};
-
 typedef struct sd_lldp sd_lldp;
-typedef struct sd_lldp_packet sd_lldp_packet;
+typedef struct sd_lldp_neighbor sd_lldp_neighbor;
 
-typedef void (*sd_lldp_callback_t)(sd_lldp *lldp, int event, void *userdata);
+typedef void (*sd_lldp_callback_t)(sd_lldp *lldp, void *userdata);
 
-int sd_lldp_new(int ifindex, sd_lldp **ret);
+int sd_lldp_new(sd_lldp **ret, int ifindex);
 sd_lldp* sd_lldp_unref(sd_lldp *lldp);
 
 int sd_lldp_start(sd_lldp *lldp);
@@ -55,32 +45,46 @@ int sd_lldp_attach_event(sd_lldp *lldp, sd_event *event, int64_t priority);
 int sd_lldp_detach_event(sd_lldp *lldp);
 
 int sd_lldp_set_callback(sd_lldp *lldp, sd_lldp_callback_t cb, void *userdata);
-int sd_lldp_save(sd_lldp *lldp, const char *file);
-
-int sd_lldp_packet_read_chassis_id(sd_lldp_packet *tlv, uint8_t *type, uint8_t **data, uint16_t *length);
-int sd_lldp_packet_read_port_id(sd_lldp_packet *tlv, uint8_t *type, uint8_t **data, uint16_t *length);
-int sd_lldp_packet_read_ttl(sd_lldp_packet *tlv, uint16_t *ttl);
-int sd_lldp_packet_read_system_name(sd_lldp_packet *tlv, char **data, uint16_t *length);
-int sd_lldp_packet_read_system_description(sd_lldp_packet *tlv, char **data, uint16_t *length);
-int sd_lldp_packet_read_system_capability(sd_lldp_packet *tlv, uint16_t *data);
-int sd_lldp_packet_read_port_description(sd_lldp_packet *tlv, char **data, uint16_t *length);
-
-/* IEEE 802.1 organizationally specific TLVs */
-int sd_lldp_packet_read_port_vlan_id(sd_lldp_packet *tlv, uint16_t *id);
-int sd_lldp_packet_read_port_protocol_vlan_id(sd_lldp_packet *tlv, uint8_t *flags, uint16_t *id);
-int sd_lldp_packet_read_vlan_name(sd_lldp_packet *tlv, uint16_t *vlan_id, char **name, uint16_t *length);
-int sd_lldp_packet_read_management_vid(sd_lldp_packet *tlv, uint16_t *id);
-int sd_lldp_packet_read_link_aggregation(sd_lldp_packet *tlv, uint8_t *status, uint32_t *id);
-
-sd_lldp_packet *sd_lldp_packet_ref(sd_lldp_packet *tlv);
-sd_lldp_packet *sd_lldp_packet_unref(sd_lldp_packet *tlv);
-
-int sd_lldp_packet_get_destination_type(sd_lldp_packet *tlv, int *dest);
 
-int sd_lldp_get_packets(sd_lldp *lldp, sd_lldp_packet ***tlvs);
+/* Controls how much and what to store in the neighbors database */
+int sd_lldp_set_neighbors_max(sd_lldp *lldp, uint64_t n);
+int sd_lldp_match_capabilities(sd_lldp *lldp, uint16_t mask);
+
+int sd_lldp_get_neighbors(sd_lldp *lldp, sd_lldp_neighbor ***neighbors);
+
+int sd_lldp_neighbor_from_raw(sd_lldp_neighbor **ret, const void *raw, size_t raw_size);
+sd_lldp_neighbor *sd_lldp_neighbor_ref(sd_lldp_neighbor *n);
+sd_lldp_neighbor *sd_lldp_neighbor_unref(sd_lldp_neighbor *n);
+
+/* Access to LLDP frame metadata */
+int sd_lldp_neighbor_get_source_address(sd_lldp_neighbor *n, struct ether_addr* address);
+int sd_lldp_neighbor_get_destination_address(sd_lldp_neighbor *n, struct ether_addr* address);
+int sd_lldp_neighbor_get_raw(sd_lldp_neighbor *n, const void **ret, size_t *size);
+
+/* High-level, direct, parsed out field access. These fields exist at most once, hence may be queried directly. */
+int sd_lldp_neighbor_get_chassis_id(sd_lldp_neighbor *n, uint8_t *type, const void **ret, size_t *size);
+int sd_lldp_neighbor_get_chassis_id_as_string(sd_lldp_neighbor *n, const char **ret);
+int sd_lldp_neighbor_get_port_id(sd_lldp_neighbor *n, uint8_t *type, const void **ret, size_t *size);
+int sd_lldp_neighbor_get_port_id_as_string(sd_lldp_neighbor *n, const char **ret);
+int sd_lldp_neighbor_get_ttl(sd_lldp_neighbor *n, uint16_t *ret);
+int sd_lldp_neighbor_get_system_name(sd_lldp_neighbor *n, const char **ret);
+int sd_lldp_neighbor_get_system_description(sd_lldp_neighbor *n, const char **ret);
+int sd_lldp_neighbor_get_port_description(sd_lldp_neighbor *n, const char **ret);
+int sd_lldp_neighbor_get_system_capabilities(sd_lldp_neighbor *n, uint16_t *ret);
+int sd_lldp_neighbor_get_enabled_capabilities(sd_lldp_neighbor *n, uint16_t *ret);
+
+/* Low-level, iterative TLV access. This is for evertyhing else, it iteratively goes through all available TLVs
+ * (including the ones covered with the calls above), and allows multiple TLVs for the same fields. */
+int sd_lldp_neighbor_tlv_rewind(sd_lldp_neighbor *n);
+int sd_lldp_neighbor_tlv_next(sd_lldp_neighbor *n);
+int sd_lldp_neighbor_tlv_get_type(sd_lldp_neighbor *n, uint8_t *type);
+int sd_lldp_neighbor_tlv_is_type(sd_lldp_neighbor *n, uint8_t type);
+int sd_lldp_neighbor_tlv_get_oui(sd_lldp_neighbor *n, uint8_t oui[3], uint8_t *subtype);
+int sd_lldp_neighbor_tlv_is_oui(sd_lldp_neighbor *n, const uint8_t oui[3], uint8_t subtype);
+int sd_lldp_neighbor_tlv_get_raw(sd_lldp_neighbor *n, const void **ret, size_t *size);
 
 _SD_DEFINE_POINTER_CLEANUP_FUNC(sd_lldp, sd_lldp_unref);
-_SD_DEFINE_POINTER_CLEANUP_FUNC(sd_lldp_packet, sd_lldp_packet_unref);
+_SD_DEFINE_POINTER_CLEANUP_FUNC(sd_lldp_neighbor, sd_lldp_neighbor_unref);
 
 _SD_END_DECLARATIONS;
 
diff --git a/src/systemd/sd-network.h b/src/systemd/sd-network.h
index e20d12c44d..56986c984d 100644
--- a/src/systemd/sd-network.h
+++ b/src/systemd/sd-network.h
@@ -133,8 +133,6 @@ int sd_network_link_get_dnssec(int ifindex, char **dnssec);
  */
 int sd_network_link_get_dnssec_negative_trust_anchors(int ifindex, char ***nta);
 
-int sd_network_link_get_lldp(int ifindex, char **lldp);
-
 /* Get the search DNS domain names for a given link. */
 int sd_network_link_get_search_domains(int ifindex, char ***domains);