SCTP stack (RFC4960)

== CONTENT ==
* SCTP chunks definition as per RFC4960;
* Helper functions to set/get values to/from the corresponding chunks;
* Hooks to the session/application layers;
* Complete state-machine handling;
* Implementation for unexpected chunk received in a certain
state (state-machine error handling)
* Support for 1-single connection;
* Sample application to test receive/transmit data-path;
* Test to validate SCTP stack;

Change-Id: I1b55c455ab400be9513f4e094dadfc3181d2ebc9
Signed-off-by: Marco Varlese <marco.varlese@suse.com>

1 files changed, 1445 insertions, 0 deletions

diff --git a/src/vnet/sctp/sctp_packet.h b/src/vnet/sctp/sctp_packet.h
new file mode 100644
index 00000000000..4c358db6d3b
--- /dev/null
+++ b/src/vnet/sctp/sctp_packet.h
@@ -0,0 +1,1445 @@
+/*
+ * Copyright (c) 2017 SUSE LLC.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef included_vnet_sctp_packet_h
+#define included_vnet_sctp_packet_h
+
+#include <stdbool.h>
+
+#include <vnet/ip/ip4_packet.h>
+#include <vnet/ip/ip6_packet.h>
+
+/*
+ * As per RFC 4960
+ * https://tools.ietf.org/html/rfc4960
+ */
+
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |     Source Port Number        |     Destination Port Number   |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                      Verification Tag                         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                           Checksum                            |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  /*
+   * This is the SCTP sender's port number. It can be used by the
+   * receiver in combination with the source IP address, the SCTP
+   * destination port, and possibly the destination IP address to
+   * identify the association to which this packet belongs.
+   * The port number 0 MUST NOT be used.
+   */
+  u16 src_port;
+
+  /*
+   * This is the SCTP port number to which this packet is destined.
+   * The receiving host will use this port number to de-multiplex the
+   * SCTP packet to the correct receiving endpoint/application.
+   * The port number 0 MUST NOT be used.
+   */
+  u16 dst_port;
+
+  /*
+   * The receiver of this packet uses the Verification Tag to validate
+   * the sender of this SCTP packet.  On transmit, the value of this
+   * Verification Tag MUST be set to the value of the Initiate Tag
+   * received from the peer endpoint during the association
+   * initialization, with the following exceptions:
+   * - A packet containing an INIT chunk MUST have a zero Verification
+   *   Tag.
+   * - A packet containing a SHUTDOWN COMPLETE chunk with the T bit
+   *   set MUST have the Verification Tag copied from the packet with
+   *   the SHUTDOWN ACK chunk.
+   * - A packet containing an ABORT chunk may have the verification tag
+   *   copied from the packet that caused the ABORT to be sent.
+   * An INIT chunk MUST be the only chunk in the SCTP packet carrying it.
+   */
+  u32 verification_tag;
+
+  /*
+   * This field contains the checksum of this SCTP packet.
+   * SCTP uses the CRC32c algorithm.
+   */
+  u32 checksum;
+
+} sctp_header_t;
+
+always_inline void
+vnet_set_sctp_src_port (sctp_header_t * h, u16 src_port)
+{
+  h->src_port = clib_host_to_net_u16 (src_port);
+}
+
+always_inline u16
+vnet_get_sctp_src_port (sctp_header_t * h)
+{
+  return (clib_net_to_host_u16 (h->src_port));
+}
+
+always_inline void
+vnet_set_sctp_dst_port (sctp_header_t * h, u16 dst_port)
+{
+  h->dst_port = clib_host_to_net_u16 (dst_port);
+}
+
+always_inline u16
+vnet_get_sctp_dst_port (sctp_header_t * h)
+{
+  return (clib_net_to_host_u16 (h->dst_port));
+}
+
+always_inline void
+vnet_set_sctp_verification_tag (sctp_header_t * h, u32 verification_tag)
+{
+  h->verification_tag = clib_host_to_net_u32 (verification_tag);
+}
+
+always_inline u32
+vnet_get_sctp_verification_tag (sctp_header_t * h)
+{
+  return (clib_net_to_host_u32 (h->verification_tag));
+}
+
+always_inline void
+vnet_set_sctp_checksum (sctp_header_t * h, u32 checksum)
+{
+  h->checksum = clib_host_to_net_u32 (checksum);
+}
+
+always_inline u32
+vnet_get_sctp_checksum (sctp_header_t * h)
+{
+  return (clib_net_to_host_u32 (h->checksum));
+}
+
+/*
+ * Multiple chunks can be bundled into one SCTP packet up to the MTU
+ * size, except for the INIT, INIT ACK, and SHUTDOWN COMPLETE chunks.
+ * These chunks MUST NOT be bundled with any other chunk in a packet.
+ *
+ *
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                        Common Header                          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                          Chunk #1                             |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                           ...                                 |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                          Chunk #n                             |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+
+typedef enum
+{
+  DATA = 0,
+  INIT,
+  INIT_ACK,
+  SACK,
+  HEARTBEAT,
+  HEARTBEAT_ACK,
+  ABORT,
+  SHUTDOWN,
+  SHUTDOWN_ACK,
+  OPERATION_ERROR,
+  COOKIE_ECHO,
+  COOKIE_ACK,
+  ECNE,
+  CWR,
+  SHUTDOWN_COMPLETE
+} sctp_chunk_type;
+
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Chunk Type  | Chunk  Flags  |        Chunk Length           |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  /*
+   * This field identifies the type of information contained in the
+   * Chunk Value field. It takes a value from 0 to 254.
+   * The value of 255 is reserved for future use as an extension field.
+   *
+   * The values of Chunk Types are defined as follows:
+   * ID Value    Chunk Type
+   * -----       ----------
+   *  0          - Payload Data (DATA)
+   *  1          - Initiation (INIT)
+   *  2          - Initiation Acknowledgement (INIT ACK)
+   *  3          - Selective Acknowledgement (SACK)
+   *  4          - Heartbeat Request (HEARTBEAT)
+   *  5          - Heartbeat Acknowledgement (HEARTBEAT ACK)
+   *  6          - Abort (ABORT)
+   *  7          - Shutdown (SHUTDOWN)
+   *  8          - Shutdown Acknowledgement (SHUTDOWN ACK)
+   *  9          - Operation Error (ERROR)
+   *  10         - State Cookie (COOKIE ECHO)
+   *  11         - Cookie Acknowledgement (COOKIE ACK)
+   *  12         - Reserved for Explicit Congestion Notification Echo (ECNE)
+   *  13         - Reserved for Congestion Window Reduced (CWR)
+   *  14         - Shutdown Complete (SHUTDOWN COMPLETE)
+   *  15 to 62   - available
+   *  63         - reserved for IETF-defined Chunk Extensions
+   *  64 to 126  - available
+   *  127        - reserved for IETF-defined Chunk Extensions
+   *  128 to 190 - available
+   *  191        - reserved for IETF-defined Chunk Extensions
+   *  192 to 254 - available
+   *  255        - reserved for IETF-defined Chunk Extensions
+   *
+   *  Chunk Types are encoded such that the highest-order 2 bits specify
+   *  the action that must be taken if the processing endpoint does not
+   *  recognize the Chunk Type.
+   *  00 -  Stop processing this SCTP packet and discard it, do not
+   *  process any further chunks within it.
+   *  01 -  Stop processing this SCTP packet and discard it, do not
+   *  process any further chunks within it, and report the
+   *  unrecognized chunk in an 'Unrecognized Chunk Type'.
+   *  10 -  Skip this chunk and continue processing.
+   *  11 -  Skip this chunk and continue processing, but report in an
+   *  ERROR chunk using the 'Unrecognized Chunk Type' cause of error.
+   *
+   *  Note: The ECNE and CWR chunk types are reserved for future use of
+   *  Explicit Congestion Notification (ECN);
+   */
+  //u8 type;
+
+  /*
+   * The usage of these bits depends on the Chunk type as given by the
+   * Chunk Type field.  Unless otherwise specified, they are set to 0 on
+   * transmit and are ignored on receipt.
+   */
+  //u8 flags;
+
+  /*
+   * This value represents the size of the chunk in bytes, including
+   * the Chunk Type, Chunk Flags, Chunk Length, and Chunk Value fields.
+   * Therefore, if the Chunk Value field is zero-length, the Length
+   * field will be set to 4.
+   * The Chunk Length field does not count any chunk padding.
+   * Chunks (including Type, Length, and Value fields) are padded out
+   * by the sender with all zero bytes to be a multiple of 4 bytes
+   * long. This padding MUST NOT be more than 3 bytes in total. The
+   * Chunk Length value does not include terminating padding of the
+   * chunk. However, it does include padding of any variable-length
+   * parameter except the last parameter in the chunk. The receiver
+   * MUST ignore the padding.
+   *
+   * Note: A robust implementation should accept the chunk whether or
+   * not the final padding has been included in the Chunk Length.
+   */
+  //u16 length;
+
+  u32 params;
+
+} sctp_chunks_common_hdr_t;
+
+typedef struct
+{
+  sctp_header_t hdr;
+  sctp_chunks_common_hdr_t common_hdr;
+
+} sctp_full_hdr_t;
+
+#define CHUNK_TYPE_MASK 0xFF000000
+#define CHUNK_TYPE_SHIFT 24
+
+#define CHUNK_FLAGS_MASK 0x00FF0000
+#define CHUNK_FLAGS_SHIFT 16
+
+#define CHUNK_LENGTH_MASK 0x0000FFFF
+#define CHUNK_LENGTH_SHIFT 0
+
+always_inline void
+vnet_sctp_common_hdr_params_host_to_net (sctp_chunks_common_hdr_t * h)
+{
+  h->params = clib_host_to_net_u32 (h->params);
+}
+
+always_inline void
+vnet_sctp_common_hdr_params_net_to_host (sctp_chunks_common_hdr_t * h)
+{
+  h->params = clib_net_to_host_u32 (h->params);
+}
+
+always_inline void
+vnet_sctp_set_chunk_type (sctp_chunks_common_hdr_t * h, sctp_chunk_type t)
+{
+  h->params &= ~(CHUNK_TYPE_MASK);
+  h->params |= (t << CHUNK_TYPE_SHIFT) & CHUNK_TYPE_MASK;
+}
+
+always_inline u8
+vnet_sctp_get_chunk_type (sctp_chunks_common_hdr_t * h)
+{
+  return ((h->params & CHUNK_TYPE_MASK) >> CHUNK_TYPE_SHIFT);
+}
+
+always_inline void
+vnet_sctp_set_chunk_length (sctp_chunks_common_hdr_t * h, u16 length)
+{
+  h->params &= ~(CHUNK_LENGTH_MASK);
+  h->params |= (length << CHUNK_LENGTH_SHIFT) & CHUNK_LENGTH_MASK;
+}
+
+always_inline u16
+vnet_sctp_get_chunk_length (sctp_chunks_common_hdr_t * h)
+{
+  return ((h->params & CHUNK_LENGTH_MASK) >> CHUNK_LENGTH_SHIFT);
+}
+
+/*
+ * Payload chunk
+ *
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 0    | Reserved|U|B|E|    Length                     |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                              TSN                              |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |      Stream Identifier S      |   Stream Sequence Number n    |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                  Payload Protocol Identifier                  |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * \                                                               \
+ * /                 User Data (seq n of Stream S)                 /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  /*
+   * Type (8 bits): 0
+   * Flags (8 bits):
+   * -- Reserved (5 bits): all 0s
+   * -- U bit
+   * -- B bit
+   * -- E bit
+   * Length (16 bits): This field indicates the length of the DATA chunk in
+   * bytes from the beginning of the type field to the end of the User Data
+   * field excluding any padding.
+   * A DATA chunk with one byte of user data will have Length set to 17
+   * (indicating 17 bytes). A DATA chunk with a User Data field of length L
+   * will have the Length field set to (16 + L) (indicating 16+L bytes) where
+   * L MUST be greater than 0.
+   */
+
+  /*
+   * Fragment Description Table:
+   *
+   *    B E                  Description
+   * ============================================================
+   * |  1 0 | First piece of a fragmented user message          |
+   * +----------------------------------------------------------+
+   * |  0 0 | Middle piece of a fragmented user message         |
+   * +----------------------------------------------------------+
+   * |  0 1 | Last piece of a fragmented user message           |
+   * +----------------------------------------------------------+
+   * |  1 1 | Unfragmented message                              |
+   * ============================================================
+   */
+  sctp_chunks_common_hdr_t chunk_hdr;
+
+  /*
+   * This value represents the TSN for this DATA chunk.
+   * The valid range of TSN is from 0 to 4294967295 (2**32 - 1).
+   * TSN wraps back to 0 after reaching 4294967295.
+   */
+  u32 tsn;
+
+  /*
+   * Identifies the stream to which the following user data belongs.
+   */
+  u16 stream_id;
+
+  /*
+   * This value represents the Stream Sequence Number of the following user data
+   * within the stream S. Valid range is 0 to 65535.
+   * When a user message is fragmented by SCTP for transport, the same Stream
+   * Sequence Number MUST be carried in each of the fragments of the message.
+   */
+  u16 stream_seq;
+
+  /*
+   * This value represents an application (or upper layer) specified protocol
+   * identifier. This value is passed to SCTP by its upper layer and sent to its
+   * peer. This identifier is not used by SCTP but can be used by certain network
+   * entities, as well as by the peer application, to identify the type of
+   * information being carried in this DATA chunk. This field must be sent even
+   * in fragmented DATA chunks (to make sure it is available for agents in the
+   * middle of the network).  Note that this field is NOT touched by an SCTP
+   * implementation; therefore, its byte order is NOT necessarily big endian.
+   * The upper layer is responsible for any byte order conversions to this field.
+   * The value 0 indicates that no application identifier is specified by the
+   * upper layer for this payload data.
+   */
+  u32 payload_id;
+
+  /*
+   * This is the payload user data. The implementation MUST pad the end of the
+   * data to a 4-byte boundary with all-zero bytes. Any padding MUST NOT be
+   * included in the Length field. A sender MUST never add more than 3 bytes of
+   * padding.
+   */
+  u32 data[];
+
+} sctp_payload_data_chunk_t;
+
+always_inline void
+vnet_sctp_set_ebit (sctp_payload_data_chunk_t * p, u8 enable)
+{
+  //p->chunk_hdr.flags = clib_host_to_net_u16 (enable);
+}
+
+always_inline u8
+vnet_sctp_get_ebit (sctp_payload_data_chunk_t * p)
+{
+  //return (clib_net_to_host_u16 (p->chunk_hdr.flags));
+  return 0;
+}
+
+always_inline void
+vnet_sctp_set_bbit (sctp_payload_data_chunk_t * p, u8 enable)
+{
+  //p->chunk_hdr.flags = clib_host_to_net_u16 (enable << 1);
+}
+
+always_inline u8
+vnet_sctp_get_bbit (sctp_payload_data_chunk_t * p)
+{
+  //return (clib_net_to_host_u16 (p->chunk_hdr.flags >> 1));
+  return 0;
+}
+
+always_inline void
+vnet_sctp_set_ubit (sctp_payload_data_chunk_t * p, u8 enable)
+{
+  //p->chunk_hdr.flags = clib_host_to_net_u16 (enable << 2);
+}
+
+always_inline u8
+vnet_sctp_get_ubit (sctp_payload_data_chunk_t * p)
+{
+  //return (clib_net_to_host_u16 (p->chunk_hdr.flags >> 2));
+  return 0;
+}
+
+always_inline void
+vnet_sctp_set_tsn (sctp_payload_data_chunk_t * p, u32 tsn)
+{
+  p->tsn = clib_host_to_net_u32 (tsn);
+}
+
+always_inline u32
+vnet_sctp_get_tsn (sctp_payload_data_chunk_t * p)
+{
+  return (clib_net_to_host_u32 (p->tsn));
+}
+
+always_inline void
+vnet_sctp_set_stream_id (sctp_payload_data_chunk_t * p, u16 stream_id)
+{
+  p->stream_id = clib_host_to_net_u16 (stream_id);
+}
+
+always_inline u16
+vnet_sctp_get_stream_id (sctp_payload_data_chunk_t * p)
+{
+  return (clib_net_to_host_u16 (p->stream_id));
+}
+
+always_inline void
+vnet_sctp_set_stream_seq (sctp_payload_data_chunk_t * p, u16 stream_seq)
+{
+  p->stream_seq = clib_host_to_net_u16 (stream_seq);
+}
+
+always_inline u16
+vnet_sctp_get_stream_seq (sctp_payload_data_chunk_t * p)
+{
+  return (clib_net_to_host_u16 (p->stream_seq));
+}
+
+always_inline void
+vnet_sctp_set_payload_id (sctp_payload_data_chunk_t * p, u32 payload_id)
+{
+  p->payload_id = clib_host_to_net_u32 (payload_id);
+}
+
+always_inline u32
+vnet_sctp_get_payload_id (sctp_payload_data_chunk_t * p)
+{
+  return (clib_net_to_host_u32 (p->payload_id));
+}
+
+always_inline u16
+vnet_sctp_calculate_padding (u16 base_length)
+{
+  if (base_length % 4 == 0)
+    return 0;
+
+  return (4 - base_length % 4);
+}
+
+always_inline u16
+vnet_sctp_calculate_payload_data_padding (sctp_payload_data_chunk_t * p)
+{
+  u16 payload_length = vnet_sctp_get_chunk_length (&p->chunk_hdr) -
+    sizeof (p->chunk_hdr) -
+    sizeof (p->tsn) -
+    sizeof (p->stream_id) - sizeof (p->stream_seq) - sizeof (p->payload_id);
+
+  return vnet_sctp_calculate_padding (payload_length);
+}
+
+#define DEFAULT_A_RWND 1480
+#define INBOUND_STREAMS_COUNT 1
+#define OUTBOUND_STREAMS_COUNT 1
+
+/*
+ * INIT chunk
+ *
+ * This chunk is used to initiate an SCTP association between two
+ * endpoints.
+ *
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 1    |  Chunk Flags  |      Chunk Length             |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                         Initiate Tag                          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |           Advertised Receiver Window Credit (a_rwnd)          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |  Number of Outbound Streams   |  Number of Inbound Streams    |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                          Initial TSN                          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * \                                                               \
+ * /              Optional/Variable-Length Parameters              /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * The INIT chunk contains the following parameters. Unless otherwise
+ * noted, each parameter MUST only be included once in the INIT chunk.
+ *
+ * Fixed Parameters                     Status
+ * ----------------------------------------------
+ *  Initiate Tag                        Mandatory
+ *  Advertised Receiver Window Credit   Mandatory
+ *  Number of Outbound Streams          Mandatory
+ *  Number of Inbound Streams           Mandatory
+ *  Initial TSN                         Mandatory
+ *
+ * Variable Parameters                  Status     Type Value
+ * -------------------------------------------------------------
+ *  IPv4 Address (Note 1)               Optional    5
+ *  IPv6 Address (Note 1)               Optional    6
+ *  Cookie Preservative			Optional    9
+ *  Reserved for ECN Capable (Note 2)   Optional    32768 (0x8000)
+ *  Host Name Address (Note 3)          Optional    11
+ *  Supported Address Types (Note 4)    Optional    12
+ *
+ * Note 1: The INIT chunks can contain multiple addresses that can be
+ * IPv4 and/or IPv6 in any combination.
+ *
+ * Note 2: The ECN Capable field is reserved for future use of Explicit
+ * Congestion Notification.
+ *
+ * Note 3: An INIT chunk MUST NOT contain more than one Host Name Address
+ * parameter. Moreover, the sender of the INIT MUST NOT combine any other
+ * address types with the Host Name Address in the INIT. The receiver of
+ * INIT MUST ignore any other address types if the Host Name Address parameter
+ * is present in the received INIT chunk.
+ *
+ * Note 4: This parameter, when present, specifies all the address types the
+ * sending endpoint can support.  The absence of this parameter indicates that
+ * the sending endpoint can support any address type.
+ *
+ * IMPLEMENTATION NOTE: If an INIT chunk is received with known parameters that
+ * are not optional parameters of the INIT chunk, then the receiver SHOULD
+ * process the INIT chunk and send back an INIT ACK. The receiver of the INIT
+ * chunk MAY bundle an ERROR chunk with the COOKIE ACK chunk later.
+ * However, restrictive implementations MAY send back an ABORT chunk in response
+ * to the INIT chunk. The Chunk Flags field in INIT is reserved, and all bits
+ * in it should be set to 0 by the sender and ignored by the receiver.
+ * The sequence of parameters within an INIT can be processed in any order.
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+
+  /*
+   * The receiver of the INIT (the responding end) records the value of
+   * the Initiate Tag parameter.
+   * This value MUST be placed into the Verification Tag field of every
+   * SCTP packet that the receiver of the INIT transmits within this association.
+   * The Initiate Tag is allowed to have any value except 0.
+   *
+   * If the value of the Initiate Tag in a received INIT chunk is found
+   * to be 0, the receiver MUST treat it as an error and close the
+   * association by transmitting an ABORT.
+   *
+   * The value of the INIT TAG is recommended to be random for security
+   * reasons. A good method is described in https://tools.ietf.org/html/rfc4086
+   */
+  u32 initiate_tag;
+
+  /*
+   * This value represents the dedicated buffer space, in number of bytes,
+   * the sender of the INIT has reserved in association with this window.
+   * During the life of the association, this buffer space SHOULD NOT be
+   * lessened (i.e., dedicated buffers taken away from this association);
+   * however, an endpoint MAY change the value of a_rwnd it sends in SACK
+   * chunks.
+   */
+  u32 a_rwnd;
+
+  /*
+   * Defines the number of outbound streams the sender of this INIT chunk
+   * wishes to create in this association.
+   * The value of 0 MUST NOT be used.
+   *
+   * Note: A receiver of an INIT with the OS value set to 0 SHOULD abort
+   * the association.
+   */
+  u16 outbound_streams_count;
+
+  /*
+   * Defines the maximum number of streams the sender of this INIT
+   * chunk allows the peer end to create in this association.
+   * The value 0 MUST NOT be used.
+   *
+   * Note: There is no negotiation of the actual number of streams but
+   * instead the two endpoints will use the min(requested, offered).
+   *
+   * Note: A receiver of an INIT with the MIS value of 0 SHOULD abort
+   * the association.
+   */
+  u16 inboud_streams_count;
+
+  /*
+   * Defines the initial TSN that the sender will use.
+   * The valid range is from 0 to 4294967295.
+   * This field MAY be set to the value of the Initiate Tag field.
+   */
+  u32 initial_tsn;
+
+  /* The following field allows to have multiple optional fields which are:
+   * - sctp_ipv4_address
+   * - sctp_ipv6_address
+   * - sctp_cookie_preservative
+   * - sctp_hostname_address
+   * - sctp_supported_address_types
+   */
+  u32 optional_fields[];
+
+} sctp_init_chunk_t;
+
+/*
+ * INIT ACK chunk
+ *
+ * The INIT ACK chunk is used to acknowledge the initiation of an SCTP
+ * association. The parameter part of INIT ACK is formatted similarly to the
+ * INIT chunk.
+ *
+ * It uses two extra variable parameters:
+ * - the State Cookie and
+ * - the Unrecognized Parameter:
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 2    |  Chunk Flags  |      Chunk Length             |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                         Initiate Tag                          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |              Advertised Receiver Window Credit                |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |  Number of Outbound Streams   |  Number of Inbound Streams    |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                          Initial TSN                          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * \                                                               \
+ * /              Optional/Variable-Length Parameters              /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef sctp_init_chunk_t sctp_init_ack_chunk_t;
+
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |          Parameter Type       |       Parameter Length        |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * \                                                               \
+ * /                       Parameter Value                         /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  u16 type;
+  u16 length;
+
+} sctp_opt_params_hdr_t;
+
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+  u64 mac;			/* RFC 2104 */
+  u32 creation_time;
+  u32 cookie_lifespan;
+
+} sctp_state_cookie_param_t;
+
+/*
+ *  This chunk is used only during the initialization of an association.
+ *  It is sent by the initiator of an association to its peer to complete
+ *  the initialization process.  This chunk MUST precede any DATA chunk
+ *  sent within the association, but MAY be bundled with one or more DATA
+ *  chunks in the same packet.
+ *
+ *  0                   1                   2                   3
+ *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |   Type = 10   |Chunk  Flags   |         Length                |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  /                     Cookie                                    /
+ *  \                                                               \
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+
+  sctp_state_cookie_param_t cookie;
+
+} sctp_cookie_echo_chunk_t;
+
+
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 11   |Chunk  Flags   |     Length = 4                |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+
+} sctp_cookie_ack_chunk_t;
+
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 14   |Chunk  Flags   |     Length = 4                |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+
+} sctp_shutdown_complete_chunk_t;
+
+/* OPTIONAL or VARIABLE-LENGTH parameters for INIT */
+#define SCTP_IPV4_ADDRESS_TYPE	5
+#define SCTP_IPV4_ADDRESS_TYPE_LENGTH 8
+#define SCTP_IPV6_ADDRESS_TYPE	6
+#define SCTP_IPV6_ADDRESS_TYPE_LENGTH 20
+#define SCTP_STATE_COOKIE_TYPE		7
+#define SCTP_UNRECOGNIZED_TYPE	8
+#define SCTP_COOKIE_PRESERVATIVE_TYPE	9
+#define SCTP_COOKIE_PRESERVATIVE_TYPE_LENGTH	8
+#define SCTP_HOSTNAME_ADDRESS_TYPE 	11
+#define SCTP_SUPPORTED_ADDRESS_TYPES	12
+
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |        Type = 5               |      Length = 8               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                        IPv4 Address                           |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+  /*
+   * Contains an IPv4 address of the sending endpoint.
+   * It is binary encoded.
+   */
+  ip4_address_t address;
+
+} sctp_ipv4_addr_param_t;
+
+always_inline void
+vnet_sctp_set_ipv4_address (sctp_ipv4_addr_param_t * a, ip4_address_t address)
+{
+  a->param_hdr.type = clib_host_to_net_u16 (SCTP_IPV4_ADDRESS_TYPE);
+  a->param_hdr.length = clib_host_to_net_u16 (8);
+  a->address.as_u32 = clib_host_to_net_u32 (address.as_u32);
+}
+
+always_inline u32
+vnet_sctp_get_ipv4_address (sctp_ipv4_addr_param_t * a)
+{
+  return (clib_net_to_host_u32 (a->address.as_u32));
+}
+
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |            Type = 6           |          Length = 20          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                                                               |
+ * |                         IPv6 Address                          |
+ * |                                                               |
+ * |                                                               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+  /*
+   * Contains an IPv6 address of the sending endpoint.
+   * It is binary encoded.
+   */
+  ip6_address_t address;
+
+} sctp_ipv6_addr_param_t;
+
+always_inline void
+vnet_sctp_set_ipv6_address (sctp_ipv6_addr_param_t * a, ip6_address_t address)
+{
+  a->param_hdr.type = clib_host_to_net_u16 (SCTP_IPV6_ADDRESS_TYPE);
+  a->param_hdr.length = clib_host_to_net_u16 (20);
+  a->address.as_u64[0] = clib_host_to_net_u64 (address.as_u64[0]);
+  a->address.as_u64[1] = clib_host_to_net_u64 (address.as_u64[1]);
+}
+
+always_inline ip6_address_t
+vnet_sctp_get_ipv6_address (sctp_ipv6_addr_param_t * a)
+{
+  ip6_address_t ip6_address;
+
+  ip6_address.as_u64[0] = clib_net_to_host_u64 (a->address.as_u64[0]);
+  ip6_address.as_u64[1] = clib_net_to_host_u64 (a->address.as_u64[1]);
+
+  return ip6_address;
+}
+
+/*
+ * The sender of the INIT shall use this parameter to suggest to the
+ * receiver of the INIT for a longer life-span of the State Cookie.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |          Type = 9             |          Length = 8           |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |         Suggested Cookie Life-Span Increment (msec.)          |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+  /*
+   * This parameter indicates to the receiver how much increment in
+   * milliseconds the sender wishes the receiver to add to its default
+   * cookie life-span.
+   *
+   * This optional parameter should be added to the INIT chunk by the
+   * sender when it reattempts establishing an association with a peer
+   * to which its previous attempt of establishing the association
+   * failed due to a stale cookie operation error. The receiver MAY
+   * choose to ignore the suggested cookie life-span increase for its
+   * own security reasons.
+   */
+  u32 life_span_inc;
+
+} sctp_cookie_preservative_param_t;
+
+always_inline void
+vnet_sctp_set_cookie_preservative (sctp_cookie_preservative_param_t * c,
+				   u32 life_span_inc)
+{
+  c->param_hdr.type = clib_host_to_net_u16 (SCTP_COOKIE_PRESERVATIVE_TYPE);
+  c->param_hdr.length = clib_host_to_net_u16 (8);
+  c->life_span_inc = clib_host_to_net_u32 (life_span_inc);
+}
+
+always_inline u32
+vnet_sctp_get_cookie_preservative (sctp_cookie_preservative_param_t * c)
+{
+  return (clib_net_to_host_u32 (c->life_span_inc));
+}
+
+#define FQDN_MAX_LENGTH 256
+
+/*
+ * The sender of INIT uses this parameter to pass its Host Name (in
+ * place of its IP addresses) to its peer.
+ * The peer is responsible for resolving the name.
+ * Using this parameter might make it more likely for the association to work
+ * across a NAT box.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |          Type = 11            |          Length               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * /                          Host Name                            /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+
+  /*
+   * This field contains a host name in "host name syntax" per RFC 1123
+   * Section 2.1
+   *
+   * Note: At least one null terminator is included in the Host Name
+   * string and must be included in the length.
+   */
+  char hostname[FQDN_MAX_LENGTH];
+
+} sctp_hostname_param_t;
+
+always_inline void
+vnet_sctp_set_hostname_address (sctp_hostname_param_t * h, char *hostname)
+{
+  h->param_hdr.length = FQDN_MAX_LENGTH;
+  h->param_hdr.type = clib_host_to_net_u16 (SCTP_HOSTNAME_ADDRESS_TYPE);
+  memset (h->hostname, '0', FQDN_MAX_LENGTH);
+  memcpy (h->hostname, hostname, FQDN_MAX_LENGTH);
+}
+
+#define MAX_SUPPORTED_ADDRESS_TYPES	3
+
+/*
+ * The sender of INIT uses this parameter to list all the address types
+ * it can support.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |          Type = 12            |          Length               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |        Address Type #1        |        Address Type #2        |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                            ......                             |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+
+ */
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+  u16 address_type[MAX_SUPPORTED_ADDRESS_TYPES];
+
+} sctp_supported_addr_types_param_t;
+
+always_inline void
+vnet_sctp_set_supported_address_types (sctp_supported_addr_types_param_t * s)
+{
+  s->param_hdr.type = clib_host_to_net_u16 (SCTP_SUPPORTED_ADDRESS_TYPES);
+  s->param_hdr.length = 4 /* base = type + length */  +
+    MAX_SUPPORTED_ADDRESS_TYPES * 4;	/* each address type is 4 bytes */
+
+  s->address_type[0] = clib_host_to_net_u16 (SCTP_IPV4_ADDRESS_TYPE);
+  s->address_type[1] = clib_host_to_net_u16 (SCTP_IPV6_ADDRESS_TYPE);
+  s->address_type[2] = clib_host_to_net_u16 (SCTP_HOSTNAME_ADDRESS_TYPE);
+}
+
+/*
+ * Error cause codes to be used for the sctp_error_cause.cause_code field
+ */
+#define INVALID_STREAM_IDENTIFIER	1
+#define MISSING_MANDATORY_PARAMETER	2
+#define STALE_COOKIE_ERROR		3
+#define OUT_OF_RESOURCE			4
+#define UNRESOLVABLE_ADDRESS		5
+#define UNRECOGNIZED_CHUNK_TYPE		6
+#define INVALID_MANDATORY_PARAMETER	7
+#define UNRECOGNIZED_PARAMETER		8
+#define NO_USER_DATA			9
+#define COOKIE_RECEIVED_WHILE_SHUTTING_DOWN	10
+#define RESTART_OF_ASSOCIATION_WITH_NEW_ADDR	11
+#define USER_INITIATED_ABORT		12
+#define PROTOCOL_VIOLATION		13
+
+always_inline void
+vnet_sctp_set_state_cookie (sctp_state_cookie_param_t * s)
+{
+  s->param_hdr.type = clib_host_to_net_u16 (SCTP_STATE_COOKIE_TYPE);
+
+  /* TODO: length & value to be populated */
+}
+
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+  u32 value[];
+
+} sctp_unrecognized_param_t;
+
+always_inline void
+vnet_sctp_set_unrecognized_param (sctp_unrecognized_param_t * u)
+{
+  u->param_hdr.type = clib_host_to_net_u16 (UNRECOGNIZED_PARAMETER);
+
+  /* TODO: length & value to be populated */
+}
+
+/*
+ * Selective ACK (SACK) chunk
+ *
+ * This chunk is sent to the peer endpoint to acknowledge received DATA
+ * chunks and to inform the peer endpoint of gaps in the received
+ * subsequences of DATA chunks as represented by their TSNs.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 3    |Chunk  Flags   |      Chunk Length             |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                      Cumulative TSN Ack                       |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |          Advertised Receiver Window Credit (a_rwnd)           |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | Number of Gap Ack Blocks = N  |  Number of Duplicate TSNs = X |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |  Gap Ack Block #1 Start       |   Gap Ack Block #1 End        |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * /                                                               /
+ * \                              ...                              \
+ * /                                                               /
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Gap Ack Block #N Start      |  Gap Ack Block #N End         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                       Duplicate TSN 1                         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * /                                                               /
+ * \                              ...                              \
+ * /                                                               /
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                       Duplicate TSN X                         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+  /*
+   * This parameter contains the TSN of the last DATA chunk received in
+   * sequence before a gap.  In the case where no DATA chunk has been
+   * received, this value is set to the peer's Initial TSN minus one.
+   */
+  u32 cumulative_tsn_ack;
+
+  /*
+   * This field indicates the updated receive buffer space in bytes of
+   * the sender of this SACK.
+   */
+  u32 a_rwnd;
+
+  /*
+   * Indicates the number of Gap Ack Blocks included in this SACK.
+   */
+  u16 gap_ack_blocks_count;
+
+  /*
+   * This field contains the number of duplicate TSNs the endpoint has
+   * received.  Each duplicate TSN is listed following the Gap Ack Block
+   * list.
+   */
+  u16 duplicate_tsn_count;
+
+  /*
+   * Indicates the Start offset TSN for this Gap Ack Block. To calculate
+   * the actual TSN number the Cumulative TSN Ack is added to this offset
+   * number. This calculated TSN identifies the first TSN in this Gap Ack
+   * Block that has been received.
+   */
+  u16 *gap_ack_block_start;
+
+  /*
+   * Indicates the End offset TSN for this Gap Ack Block. To calculate
+   * the actual TSN number, the Cumulative TSN Ack is added to this offset
+   * number. This calculated TSN identifies the TSN of the last DATA chunk
+   * received in this Gap Ack Block.
+   */
+  u16 *gap_ack_block_end;
+
+  /*
+   * Indicates the number of times a TSN was received in duplicate since
+   * the last SACK was sent. Every time a receiver gets a duplicate TSN
+   * (before sending the SACK), it adds it to the list of duplicates.
+   * The duplicate count is reinitialized to zero after sending each SACK.
+   */
+  u32 duplicate_tsn;
+
+} sctp_selective_ack_chunk_t;
+
+always_inline void
+vnet_sctp_set_cumulative_tsn_ack (sctp_selective_ack_chunk_t * s,
+				  u32 cumulative_tsn_ack)
+{
+  vnet_sctp_set_chunk_type (&s->chunk_hdr, SACK);
+  s->cumulative_tsn_ack = clib_host_to_net_u32 (cumulative_tsn_ack);
+}
+
+always_inline u32
+vnet_sctp_get_cumulative_tsn_ack (sctp_selective_ack_chunk_t * s)
+{
+  return clib_net_to_host_u32 (s->cumulative_tsn_ack);
+}
+
+always_inline void
+vnet_sctp_set_arwnd (sctp_selective_ack_chunk_t * s, u32 a_rwnd)
+{
+  vnet_sctp_set_chunk_type (&s->chunk_hdr, SACK);
+  s->a_rwnd = clib_host_to_net_u32 (a_rwnd);
+}
+
+always_inline u32
+vnet_sctp_get_arwnd (sctp_selective_ack_chunk_t * s)
+{
+  return clib_net_to_host_u32 (s->a_rwnd);
+}
+
+always_inline void
+vnet_sctp_set_gap_ack_blocks_count (sctp_selective_ack_chunk_t * s,
+				    u16 gap_ack_blocks_count)
+{
+  vnet_sctp_set_chunk_type (&s->chunk_hdr, SACK);
+  s->gap_ack_blocks_count = clib_host_to_net_u16 (gap_ack_blocks_count);
+
+  if (s->gap_ack_block_start == NULL)
+    s->gap_ack_block_start =
+      clib_mem_alloc (sizeof (u16) * gap_ack_blocks_count);
+  if (s->gap_ack_block_end == NULL)
+    s->gap_ack_block_end =
+      clib_mem_alloc (sizeof (u16) * gap_ack_blocks_count);
+}
+
+always_inline u16
+vnet_sctp_get_gap_ack_blocks_count (sctp_selective_ack_chunk_t * s)
+{
+  return clib_net_to_host_u32 (s->gap_ack_blocks_count);
+}
+
+always_inline void
+vnet_sctp_set_duplicate_tsn_count (sctp_selective_ack_chunk_t * s,
+				   u16 duplicate_tsn_count)
+{
+  vnet_sctp_set_chunk_type (&s->chunk_hdr, SACK);
+  s->duplicate_tsn_count = clib_host_to_net_u16 (duplicate_tsn_count);
+}
+
+always_inline u16
+vnet_sctp_get_duplicate_tsn_count (sctp_selective_ack_chunk_t * s)
+{
+  return clib_net_to_host_u16 (s->duplicate_tsn_count);
+}
+
+/*
+ * Heartbeat Info
+ *
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |    Heartbeat Info Type=1      |         HB Info Length        |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * /                  Sender-Specific Heartbeat Info               /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_opt_params_hdr_t param_hdr;
+
+  /*
+   * The Sender-Specific Heartbeat Info field should normally include
+   * information about the sender's current time when this HEARTBEAT
+   * chunk is sent and the destination transport address to which this
+   * HEARTBEAT is sent.
+   * This information is simply reflected back by the receiver in the
+   * HEARTBEAT ACK message.
+   *
+   * Note also that the HEARTBEAT message is both for reachability
+   * checking and for path verification.
+   * When a HEARTBEAT chunk is being used for path verification purposes,
+   * it MUST hold a 64-bit random nonce.
+   */
+  u64 hb_info;
+
+} sctp_hb_info_param_t;
+
+always_inline void
+vnet_sctp_set_heartbeat_info (sctp_hb_info_param_t * h, u64 hb_info,
+			      u16 hb_info_length)
+{
+  h->hb_info = clib_host_to_net_u16 (1);
+  h->param_hdr.length = clib_host_to_net_u16 (hb_info_length);
+  h->hb_info = clib_host_to_net_u64 (hb_info);
+}
+
+/*
+ * Heartbeat Request
+ *
+ * An endpoint should send this chunk to its peer endpoint to probe the
+ * reachability of a particular destination transport address defined in
+ * the present association.
+ * The parameter field contains the Heartbeat Information, which is a
+ * variable-length opaque data structure understood only by the sender.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 4    | Chunk  Flags  |      Heartbeat Length         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * \                                                               \
+ * /            Heartbeat Information TLV (Variable-Length)        /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+  sctp_hb_info_param_t hb_info;
+
+} sctp_hb_req_chunk_t;
+
+always_inline void
+vnet_sctp_set_hb_request_info (sctp_hb_req_chunk_t * h,
+			       sctp_hb_info_param_t * hb_info)
+{
+  vnet_sctp_set_chunk_type (&h->chunk_hdr, HEARTBEAT);
+  memcpy (&h->hb_info, hb_info, sizeof (h->hb_info));
+}
+
+/*
+ * Heartbeat Acknowledgement
+ *
+ * An endpoint should send this chunk to its peer endpoint as a response
+ * to a HEARTBEAT chunk.
+ * A HEARTBEAT ACK is always sent to the source IP address of the IP datagram
+ * containing the HEARTBEAT chunk to which this ack is responding.
+ */
+/*
+ *
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 5    | Chunk  Flags  |    Heartbeat Ack Length       |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * \                                                               \
+ * /            Heartbeat Information TLV (Variable-Length)        /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef sctp_hb_req_chunk_t sctp_hb_ack_chunk_t;
+
+always_inline void
+vnet_sctp_set_hb_ack_info (sctp_hb_ack_chunk_t * h,
+			   sctp_hb_info_param_t * hb_info)
+{
+  vnet_sctp_set_chunk_type (&h->chunk_hdr, HEARTBEAT_ACK);
+  memcpy (&h->hb_info, hb_info, sizeof (h->hb_info));
+}
+
+/*
+ * Error cause
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |           Cause Code          |       Cause Length            |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * /                    Cause-Specific Information                 /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+*/
+typedef struct
+{
+
+  sctp_opt_params_hdr_t param_hdr;
+  u64 cause_info;
+
+} sctp_err_cause_param_t;
+
+/*
+ * Abort Association (ABORT)
+ *
+ * The ABORT chunk is sent to the peer of an association to close the
+ * association.  The ABORT chunk may contain Cause Parameters to inform
+ * the receiver about the reason of the abort.  DATA chunks MUST NOT be
+ * bundled with ABORT.  Control chunks (except for INIT, INIT ACK, and
+ * SHUTDOWN COMPLETE) MAY be bundled with an ABORT, but they MUST be
+ * placed before the ABORT in the SCTP packet or they will be ignored by
+ * the receiver.
+ *
+ * If an endpoint receives an ABORT with a format error or no TCB is
+ * found, it MUST silently discard it.  Moreover, under any
+ * circumstances, an endpoint that receives an ABORT MUST NOT respond to
+ * that ABORT by sending an ABORT of its own.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 6    |Reserved     |T|           Length              |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * \                                                               \
+ * /                   zero or more Error Causes                   /
+ * \                                                               \
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+  sctp_err_cause_param_t err_causes[];
+
+} sctp_abort_chunk_t;
+
+always_inline void
+vnet_sctp_set_tbit (sctp_abort_chunk_t * a)
+{
+  vnet_sctp_set_chunk_type (&a->chunk_hdr, ABORT);
+  // a->chunk_hdr.flags = clib_host_to_net_u16 (1);
+}
+
+always_inline void
+vnet_sctp_unset_tbit (sctp_abort_chunk_t * a)
+{
+  vnet_sctp_set_chunk_type (&a->chunk_hdr, ABORT);
+  // a->chunk_hdr.flags = clib_host_to_net_u16 (0);
+}
+
+/*
+ * Shutdown Association (SHUTDOWN)
+ *
+ * An endpoint in an association MUST use this chunk to initiate a
+ * graceful close of the association with its peer.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 7    | Chunk  Flags  |      Length = 8               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                      Cumulative TSN Ack                       |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+  /*
+   * This parameter contains the TSN of the last chunk received in
+   * sequence before any gaps.
+   *
+   * Note: Since the SHUTDOWN message does not contain Gap Ack Blocks,
+   * it cannot be used to acknowledge TSNs received out of order. In a
+   * SACK, lack of Gap Ack Blocks that were previously included
+   * indicates that the data receiver reneged on the associated DATA
+   * chunks. Since SHUTDOWN does not contain Gap Ack Blocks, the
+   * receiver of the SHUTDOWN shouldn't interpret the lack of a Gap Ack
+   * Block as a renege.
+   */
+  u32 cumulative_tsn_ack;
+
+} sctp_shutdown_association_chunk_t;
+
+always_inline void
+vnet_sctp_set_tsn_last_received_chunk (sctp_shutdown_association_chunk_t * s,
+				       u32 tsn_last_chunk)
+{
+  vnet_sctp_set_chunk_type (&s->chunk_hdr, SHUTDOWN);
+  s->cumulative_tsn_ack = clib_host_to_net_u32 (tsn_last_chunk);
+}
+
+/*
+ * Shutdown Acknowledgement (SHUTDOWN ACK)
+ *
+ * This chunk MUST be used to acknowledge the receipt of the SHUTDOWN
+ * chunk at the completion of the shutdown process.
+ */
+/*
+ * 0                   1                   2                   3
+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |   Type = 8    |Chunk  Flags   |      Length = 4               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+typedef struct
+{
+  sctp_header_t sctp_hdr;
+  sctp_chunks_common_hdr_t chunk_hdr;
+} sctp_shutdown_ack_chunk_t;
+
+always_inline void
+vnet_sctp_fill_shutdown_ack (sctp_shutdown_ack_chunk_t * s)
+{
+  vnet_sctp_set_chunk_type (&s->chunk_hdr, SHUTDOWN_ACK);
+  vnet_sctp_set_chunk_length (&s->chunk_hdr, 4);
+}
+
+#endif /* included_vnet_sctp_packet_h */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */