@@ -255,6 +255,23 @@ uint32_t odp_packet_seg_len(odp_packet_t pkt);
uint32_t odp_packet_len(odp_packet_t pkt);
/**
+ * Packet unshared data len
+ *
+ * Returns the sum of data lengths over all unshared packet segments. These
+ * are the only bytes that should be modified by the caller. The rest of the
+ * packet should be treated as read-only.
+ *
+ * This routine will return 0 if odp_packet_has_ref() != 0 and will be the
+ * same as odp_packet_len() if odp_packet_has_ref() == 0 and
+ * odp_packet_is_ref() == 0.
+ *
+ * @param pkt Packet handle
+ *
+ * @return Packet unshared data length
+ */
+uint32_t odp_packet_unshared_len(odp_packet_t pkt);
+
+/**
* Packet headroom length
*
* Returns the current packet level headroom length.
@@ -846,6 +863,157 @@ int odp_packet_split(odp_packet_t *pkt, uint32_t len, odp_packet_t *tail);
/*
*
+ * References
+ * ********************************************************
+ *
+ */
+
+/**
+ * Create a static reference to a packet
+ *
+ * A static reference is used to obtain an additional handle for referring to
+ * a packet so that the storage behind it is not freed until all references to
+ * the packet are freed. This can be used, for example, to support efficient
+ * retransmission processing.
+ *
+ * The intent of a static reference is that both the base packet and the
+ * returned reference will be treated as read-only after this call. Results
+ * are unpredictable if this restriction is not observed.
+ *
+ * Static references have restrictions but may have performance advantages on
+ * some platforms if the caller does not intend to modify the reference
+ * packet. If modification is needed (e.g., to prefix a unique header onto the
+ * packet) then odp_packet_ref() or odp_packet_ref_pkt() should be used.
+ *
+ * @param pkt Handle of the base packet for which a static reference is
+ * to be created.
+ *
+ * @return Handle of the static reference packet
+ * @retval ODP_PACKET_INVALID Operation failed. Base packet remains unchanged.
+ */
+odp_packet_t odp_packet_ref_static(odp_packet_t pkt);
+
+/**
+ * Create a reference to a packet
+ *
+ * Create a dynamic reference to a base packet starting at a specified byte
+ * offset. This reference may be used as an argument to header manipulation
+ * APIs to prefix a unique header onto the shared base. The storage associated
+ * with the base packet is not freed until all references to it are freed,
+ * which permits easy multicasting or retransmission processing to be
+ * performed. Following a successful call, the base packet should be treated
+ * as read-only. Results are unpredictable if this restriction is not
+ * observed.
+ *
+ * This operation prepends a zero-length header onto the base packet beginning
+ * at the specified offset. This header is always drawn from the same pool as
+ * the base packet.
+ *
+ * Because references are unique packets, any bytes pushed onto the head of a
+ * reference via odp_packet_push_head() or odp_packet_extend_head() are unique
+ * to this reference and are not seen by the base packet or by any other
+ * reference to the same base packet.
+ *
+ * The base packet used as input to this routine may itself by a reference to
+ * some other base packet. Implementations MAY restrict the ability to create
+ * such compound references. Attempts to exceed any implementation limits in
+ * this regard will result in this call failing and returning
+ * ODP_PACKET_INVALID.
+ *
+ * If the caller does not indend to push a header onto the returned reference,
+ * the odp_packet_ref_static() API may be used. This may be a more efficient
+ * means of obtaining another reference to a base packet that will be treated
+ * as read-only.
+ *
+ * @param pkt Handle of the base packet for which a reference is to be
+ * created.
+ *
+ * @param offset Byte offset in the base packet at which the shared reference
+ * is to begin. Must be in the range 0..odp_packet_len(pkt)-1.
+ *
+ * @return Handle of the reference packet
+ * @retval ODP_PACKET_INVALID Operation failed. Base packet remains unchanged.
+ *
+
+ */
+odp_packet_t odp_packet_ref(odp_packet_t pkt, uint32_t offset);
+
+/**
+ * Create a reference to another packet from a header packet
+ *
+ * Create a dynamic reference to a base packet starting at a specified byte
+ * offset by prepending a supplied header packet. The resulting reference
+ * consists of the unshared header followed by the shared base packet starting
+ * at the specified offset. This shared portion should be regarded as
+ * read-only. The storage associated with the shared portion of the reference
+ * is not freed until all references to it are freed, which permits easy
+ * multicasting or retransmission processing to be performed.
+ *
+ * Either packet input to this routine may itself be a reference, however
+ * individual implementations MAY impose limits on how deeply splices may be
+ * nested and fail the call if those limits are exceeded.
+ *
+ * The packets used as input to this routine may reside in different pools,
+ * however individual implementations MAY require that both reside in the same
+ * pool and fail the call if this restriction is not observed.
+ *
+ * odp_packet_pool() on the returned reference returns the pool id of the
+ * header packet.
+ *
+ * @param pkt Handle of the base packet for which a reference is to be
+ * created.
+ *
+ * @param offset Byte offset in the base packet at which the shared reference
+ * to begin. Must be in the range 0..odp_packet_len(pkt)-1.
+ *
+ * @param hdr Handle of the header packet to be prefixed onto the base
+ * packet to create the reference. If this is specified as
+ * ODP_PACKET_INVALID, this call is equivalent to
+ * odp_packet_ref(). The supplied hdr must be distinct from
+ * the base pkt and results are undefined if an attempt is made
+ * to create circular references.
+ *
+ * @return Handle of the reference packet. This may or may not be the
+ * same as the input hdr packet. The caller should only use this
+ * handle since the original hdr packet no longer has any
+ * independent existence.
+ *
+ * @retval ODP_PACKET_INVALID If the reference failed. In this case both pkt
+ * and hdr are unchanged.
+ */
+odp_packet_t odp_packet_ref_pkt(odp_packet_t pkt, uint32_t offset,
+ odp_packet_t hdr);
+
+/**
+ * Test if a packet is a reference
+ *
+ * A packet is a reference if it was created by odp_packet_ref() or
+ * odp_packet_ref_pkt(). Note that a reference created from another
+ * reference is considered a compound reference. Calls on such packets will
+ * result in return values greater than 1.
+ *
+ * @param pkt Packet handle
+ *
+ * @retval 0 Packet is not a reference
+ * @retval >0 Packet is a reference consisting of N individual packets.
+ */
+int odp_packet_is_ref(odp_packet_t pkt);
+
+/**
+ * Test if a packet has a reference
+ *
+ * A packet has a reference if a reference was created on it by
+ * odp_packet_ref_static(), odp_packet_ref(), or odp_packet_ref_pkt().
+ *
+ * @param pkt Packet handle
+ *
+ * @retval 0 Packet does not have any references
+ * @retval >0 Packet has N references based on it
+ */
+int odp_packet_has_ref(odp_packet_t pkt);
+
+/*
+ *
* Copy
* ********************************************************
*
Introduce three new APIs that support efficient sharing of portions of packets. odp_packet_ref_static() creates an alias for a base packet odp_packet_ref() creates a reference to a base packet odp_packet_ref_pkt() creates a reference to a base packet from a supplied header packet In addition, three other APIs simplify working with references odp_packet_is_ref() says whether a packet is a reference odp_packet_has_ref() says whether a packet has had a reference made to it odp_packet_unshared_len() gives the length of the prefix bytes that are unique to this reference. These are the only bytes of the packet that may be modified safely. Signed-off-by: Bill Fischofer <bill.fischofer@linaro.org> --- include/odp/api/spec/packet.h | 168 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 168 insertions(+) -- 2.7.4