bfdd: import data plane protocol header

The BFD data plane header has definitions for the data plane
communication protocol that will be used to implement the distributed
BFD feature.

Signed-off-by: Rafael Zalamena <rzalamena@opensourcerouting.org>

1 files changed, 381 insertions, 0 deletions

diff --git a/bfdd/bfddp_packet.h b/bfdd/bfddp_packet.h
new file mode 100644
index 000000000..8865baef6
--- /dev/null
+++ b/bfdd/bfddp_packet.h
@@ -0,0 +1,381 @@
+/*
+ * BFD Data Plane protocol messages header.
+ *
+ * Copyright (C) 2020 Network Device Education Foundation, Inc. ("NetDEF")
+ *                    Rafael F. Zalamena
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the “Software”), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+/**
+ * \file bfddp_packet.h
+ */
+#ifndef BFD_DP_PACKET_H
+#define BFD_DP_PACKET_H
+
+#include <netinet/in.h>
+
+#include <stdint.h>
+
+/*
+ * Protocol definitions.
+ */
+
+/**
+ * BFD protocol version as defined in RFC5880 Section 4.1 Generic BFD Control
+ * Packet Format.
+ */
+#define BFD_PROTOCOL_VERSION 1
+
+/** Default data plane port. */
+#define BFD_DATA_PLANE_DEFAULT_PORT 50700
+
+/** BFD single hop UDP port, as defined in RFC 5881 Section 4. Encapsulation. */
+#define BFD_SINGLE_HOP_PORT 3784
+
+/** BFD multi hop UDP port, as defined in RFC 5883 Section 5. Encapsulation. */
+#define BFD_MULTI_HOP_PORT 4784
+
+/** Default slow start multiplier. */
+#define SLOWSTART_DMULT 3
+/** Default slow start transmission speed. */
+#define SLOWSTART_TX 1000000u
+/** Default slow start receive speed. */
+#define SLOWSTART_RX 1000000u
+/** Default slow start echo receive speed. */
+#define SLOWSTART_ERX 0u
+
+/*
+ * BFD single hop source UDP ports. As defined in RFC 5881 Section 4.
+ * Encapsulation.
+ */
+#define BFD_SOURCE_PORT_BEGIN 49152
+#define BFD_SOURCE_PORT_END 65535
+
+/** BFD data plane protocol version. */
+#define BFD_DP_VERSION 1
+
+/** BFD data plane message types. */
+enum bfddp_message_type {
+	/** Ask for BFD daemon or data plane for echo packet. */
+	ECHO_REQUEST = 0,
+	/** Answer a ECHO_REQUEST packet. */
+	ECHO_REPLY = 1,
+	/** Add or update BFD peer session. */
+	DP_ADD_SESSION = 2,
+	/** Delete BFD peer session. */
+	DP_DELETE_SESSION = 3,
+	/** Tell BFD daemon state changed: timer expired or session down. */
+	BFD_STATE_CHANGE = 4,
+
+	/** Ask for BFD session counters. */
+	DP_REQUEST_SESSION_COUNTERS = 5,
+	/** Tell BFD daemon about counters values. */
+	BFD_SESSION_COUNTERS = 6,
+};
+
+/**
+ * `ECHO_REQUEST`/`ECHO_REPLY` data payload.
+ *
+ * Data plane might use whatever precision it wants for `dp_time`
+ * field, however if you want to be able to tell the delay between
+ * data plane packet send and BFD daemon packet processing you should
+ * use `gettimeofday()` and have the data plane clock synchronized with
+ * BFD daemon (not a problem if data plane runs in the same system).
+ *
+ * Normally data plane will only check the time stamp it sent to determine
+ * the whole packet trip time.
+ */
+struct bfddp_echo {
+	/** Filled by data plane. */
+	uint64_t dp_time;
+	/** Filled by BFD daemon. */
+	uint64_t bfdd_time;
+};
+
+
+/** BFD session flags. */
+enum bfddp_session_flag {
+	/** Set when using multi hop. */
+	SESSION_MULTIHOP = (1 << 0),
+	/** Set when using demand mode. */
+	SESSION_DEMAND = (1 << 1),
+	/** Set when using cbit (Control Plane Independent). */
+	SESSION_CBIT = (1 << 2),
+	/** Set when using echo mode. */
+	SESSION_ECHO = (1 << 3),
+	/** Set when using IPv6. */
+	SESSION_IPV6 = (1 << 4),
+	/** Set when using passive mode. */
+	SESSION_PASSIVE = (1 << 5),
+	/** Set when session is administrative down. */
+	SESSION_SHUTDOWN = (1 << 6),
+};
+
+/**
+ * `DP_ADD_SESSION`/`DP_DELETE_SESSION` data payload.
+ *
+ * `lid` is unique in BFD daemon so it might be used as key for data
+ * structures lookup.
+ */
+struct bfddp_session {
+	/** Important session flags. \see bfddp_session_flag. */
+	uint32_t flags;
+	/**
+	 * Session source address.
+	 *
+	 * Check `flags` field for `SESSION_IPV6` before using as IPv6.
+	 */
+	struct in6_addr src;
+	/**
+	 * Session destination address.
+	 *
+	 * Check `flags` field for `SESSION_IPV6` before using as IPv6.
+	 */
+	struct in6_addr dst;
+
+	/** Local discriminator. */
+	uint32_t lid;
+	/**
+	 * Minimum desired transmission interval (in microseconds) without
+	 * jitter.
+	 */
+	uint32_t min_tx;
+	/**
+	 * Required minimum receive interval rate (in microseconds) without
+	 * jitter.
+	 */
+	uint32_t min_rx;
+	/**
+	 * Required minimum echo receive interval rate (in microseconds)
+	 * without jitter.
+	 */
+	uint32_t min_echo_rx;
+	/** Amount of milliseconds to wait before starting the session */
+	uint32_t hold_time;
+
+	/** Minimum TTL. */
+	uint8_t ttl;
+	/** Detection multiplier. */
+	uint8_t detect_mult;
+	/** Reserved / zeroed. */
+	uint16_t zero;
+
+	/** Interface index (set to `0` when unavailable). */
+	uint32_t ifindex;
+	/** Interface name (empty when unavailable). */
+	char ifname[64];
+
+	/* TODO: missing authentication. */
+};
+
+/** BFD packet state values as defined in RFC 5880, Section 4.1. */
+enum bfd_state_value {
+	/** Session is administratively down. */
+	STATE_ADMINDOWN = 0,
+	/** Session is down or went down. */
+	STATE_DOWN = 1,
+	/** Session is initializing. */
+	STATE_INIT = 2,
+	/** Session is up. */
+	STATE_UP = 3,
+};
+
+/** BFD diagnostic field values as defined in RFC 5880, Section 4.1. */
+enum bfd_diagnostic_value {
+	/** Nothing was diagnosed. */
+	DIAG_NOTHING = 0,
+	/** Control detection time expired. */
+	DIAG_CONTROL_EXPIRED = 1,
+	/** Echo function failed. */
+	DIAG_ECHO_FAILED = 2,
+	/** Neighbor signaled down. */
+	DIAG_DOWN = 3,
+	/** Forwarding plane reset. */
+	DIAG_FP_RESET = 4,
+	/** Path down. */
+	DIAG_PATH_DOWN = 5,
+	/** Concatenated path down. */
+	DIAG_CONCAT_PATH_DOWN = 6,
+	/** Administratively down. */
+	DIAG_ADMIN_DOWN = 7,
+	/** Reverse concatenated path down. */
+	DIAG_REV_CONCAT_PATH_DOWN = 8,
+};
+
+/** BFD remote state flags. */
+enum bfd_remote_flags {
+	/** Control Plane Independent bit. */
+	RBIT_CPI = (1 << 0),
+	/** Demand mode bit. */
+	RBIT_DEMAND = (1 << 1),
+	/** Multipoint bit. */
+	RBIT_MP = (1 << 2),
+};
+
+/**
+ * `BFD_STATE_CHANGE` data payload.
+ */
+struct bfddp_state_change {
+	/** Local discriminator. */
+	uint32_t lid;
+	/** Remote discriminator. */
+	uint32_t rid;
+	/** Remote configurations/bits set. \see bfd_remote_flags. */
+	uint32_t remote_flags;
+	/** Remote minimum desired transmission interval. */
+	uint32_t desired_tx;
+	/** Remote minimum receive interval. */
+	uint32_t required_rx;
+	/** Remote minimum echo receive interval. */
+	uint32_t required_echo_rx;
+	/** Remote state. \see bfd_state_values.*/
+	uint8_t state;
+	/** Remote diagnostics (if any) */
+	uint8_t diagnostics;
+	/** Remote detection multiplier. */
+	uint8_t detection_multiplier;
+};
+
+/**
+ * BFD control packet state bits definition.
+ */
+enum bfddp_control_state_bits {
+	/** Used to request connection establishment signal. */
+	STATE_POLL_BIT = (1 << 5),
+	/** Finalizes the connection establishment signal. */
+	STATE_FINAL_BIT = (1 << 4),
+	/** Signalizes that forward plane doesn't depend on control plane. */
+	STATE_CPI_BIT = (1 << 3),
+	/** Signalizes the use of authentication. */
+	STATE_AUTH_BIT = (1 << 2),
+	/** Signalizes that peer is using demand mode. */
+	STATE_DEMAND_BIT = (1 << 1),
+	/** Used in RFC 8562 implementation. */
+	STATE_MULTI_BIT = (1 << 0),
+};
+
+/**
+ * BFD control packet.
+ *
+ * As defined in 'RFC 5880 Section 4.1 Generic BFD Control Packet Format'.
+ */
+struct bfddp_control_packet {
+	/** (3 bits version << 5) | (5 bits diag). */
+	uint8_t version_diag;
+	/**
+	 * (2 bits state << 6) | (6 bits flags)
+	 *
+	 * \see bfd_state_value, bfddp_control_state_bits.
+	 */
+	uint8_t state_bits;
+	/** Detection multiplier. */
+	uint8_t detection_multiplier;
+	/** Packet length in bytes. */
+	uint8_t length;
+	/** Our discriminator. */
+	uint32_t local_id;
+	/** Remote system discriminator. */
+	uint32_t remote_id;
+	/** Desired minimum send interval in microseconds. */
+	uint32_t desired_tx;
+	/** Desired minimum receive interval in microseconds. */
+	uint32_t required_rx;
+	/** Desired minimum echo receive interval in microseconds. */
+	uint32_t required_echo_rx;
+};
+
+/**
+ * The protocol wire message header structure.
+ */
+struct bfddp_message_header {
+	/** Protocol version format. \see BFD_DP_VERSION. */
+	uint8_t version;
+	/** Reserved / zero field. */
+	uint8_t zero;
+	/** Message contents type. \see bfddp_message_type. */
+	uint16_t type;
+	/**
+	 * Message identification (to pair request/response).
+	 *
+	 * The ID `0` is reserved for asynchronous messages (e.g. unrequested
+	 * messages).
+	 */
+	uint16_t id;
+	/** Message length. */
+	uint16_t length;
+};
+
+/**
+ * Data plane session counters request.
+ *
+ * Message type: `DP_REQUEST_SESSION_COUNTERS`.
+ */
+struct bfddp_request_counters {
+	/** Session local discriminator. */
+	uint32_t lid;
+};
+
+/**
+ * BFD session counters reply.
+ *
+ * Message type: `BFD_SESSION_COUNTERS`.
+ */
+struct bfddp_session_counters {
+	/** Session local discriminator. */
+	uint32_t lid;
+
+	/** Control packet bytes input. */
+	uint64_t control_input_bytes;
+	/** Control packets input. */
+	uint64_t control_input_packets;
+	/** Control packet bytes output. */
+	uint64_t control_output_bytes;
+	/** Control packets output. */
+	uint64_t control_output_packets;
+
+	/** Echo packet bytes input. */
+	uint64_t echo_input_bytes;
+	/** Echo packets input. */
+	uint64_t echo_input_packets;
+	/** Echo packet bytes output. */
+	uint64_t echo_output_bytes;
+	/** Echo packets output. */
+	uint64_t echo_output_packets;
+};
+
+/**
+ * The protocol wire messages structure.
+ */
+struct bfddp_message {
+	/** Message header. \see bfddp_message_header. */
+	struct bfddp_message_header header;
+
+	/** Message payload. \see bfddp_message_type. */
+	union {
+		struct bfddp_echo echo;
+		struct bfddp_session session;
+		struct bfddp_state_change state;
+		struct bfddp_control_packet control;
+		struct bfddp_request_counters counters_req;
+		struct bfddp_session_counters session_counters;
+	} data;
+};
+
+#endif /* BFD_DP_PACKET_H */