rte_gso.h File Reference

#include <stdint.h>
#include <rte_mbuf.h>

Go to the source code of this file.

Data Structures
struct	rte_gso_ctx

Macros
#define	RTE_GSO_FLAG_IPID_FIXED   (1ULL << 0)

Functions
int	rte_gso_segment (struct rte_mbuf *pkt, const struct rte_gso_ctx *ctx, struct rte_mbuf **pkts_out, uint16_t nb_pkts_out)

Detailed Description

Interface to GSO library

Definition in file rte_gso.h.

Macro Definition Documentation

RTE_GSO_FLAG_IPID_FIXED

#define RTE_GSO_FLAG_IPID_FIXED   (1ULL << 0)

Use fixed IP ids for output GSO segments. Setting 0 indicates using incremental IP ids.

Definition at line 29 of file rte_gso.h.

Function Documentation

rte_gso_segment()

int rte_gso_segment	(	struct rte_mbuf *	pkt,
		const struct rte_gso_ctx *	ctx,
		struct rte_mbuf **	pkts_out,
		uint16_t	nb_pkts_out
	)

Segmentation function, which supports processing of both single- and multi- MBUF packets.

Note that we refer to the packets that are segmented from the input packet as 'GSO segments'. rte_gso_segment() doesn't check if the input packet has correct checksums, and doesn't update checksums for output GSO segments. Additionally, it doesn't process IP fragment packets.

Before calling rte_gso_segment(), applications must set proper ol_flags for the packet. The GSO library uses the same macros as that of TSO. For example, set PKT_TX_TCP_SEG and PKT_TX_IPV4 in ol_flags to segment a TCP/IPv4 packet. If rte_gso_segment() succeeds, the PKT_TX_TCP_SEG flag is removed for all GSO segments and the input packet.

Each of the newly-created GSO segments is organized as a two-segment MBUF, where the first segment is a standard MBUF, which stores a copy of packet header, and the second is an indirect MBUF which points to a section of data in the input packet. Since each GSO segment has multiple MBUFs (i.e. typically 2 MBUFs), the driver of the interface which the GSO segments are sent to should support transmission of multi-segment packets.

If the input packet is GSO'd, all the indirect segments are attached to the input packet.

rte_gso_segment() will not free the input packet no matter whether it is GSO'd or not, the application should free it after calling rte_gso_segment().

If the memory space in pkts_out or MBUF pools is insufficient, this function fails, and it returns (-1) * errno. Otherwise, GSO succeeds, and this function returns the number of output GSO segments filled in pkts_out.

Parameters

pkt	The packet mbuf to segment.
ctx	GSO context object pointer.
pkts_out	Pointer array used to store the MBUF addresses of output GSO segments, when rte_gso_segment() succeeds.
nb_pkts_out	The max number of items that pkts_out can keep.

Returns

• The number of GSO segments filled in pkts_out on success.
• Return 0 if it does not need to be GSO'd.
• Return -ENOMEM if run out of memory in MBUF pools.
• Return -EINVAL for invalid parameters.