DPDK 22.11.5
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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) |
Interface to GSO library
Definition in file rte_gso.h.
#define RTE_GSO_FLAG_IPID_FIXED (1ULL << 0) |
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 RTE_MBUF_F_TX_TCP_SEG and RTE_MBUF_F_TX_IPV4 in ol_flags to segment a TCP/IPv4 packet. If rte_gso_segment() succeeds, the RTE_MBUF_F_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.
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. |