numam-dpdk/lib/librte_gso/gso_udp4.c
Jiayu Hu b166d4f30b gso: support UDP/IPv4 fragmentation
This patch adds GSO support for UDP/IPv4 packets. Supported packets
may include a single VLAN tag. UDP/IPv4 GSO doesn't check if input
packets have correct checksums, and doesn't update checksums for
output packets (the responsibility for this lies with the application).
Additionally, UDP/IPv4 GSO doesn't process IP fragmented packets.

UDP/IPv4 GSO uses two chained MBUFs, one direct MBUF and one indrect
MBUF, to organize an output packet. The direct MBUF stores the packet
header, while the indirect mbuf simply points to a location within the
original packet's payload. Consequently, use of UDP GSO requires
multi-segment MBUF support in the TX functions of the NIC driver.

If a packet is GSO'd, UDP/IPv4 GSO reduces its MBUF refcnt by 1. As a
result, when all of its GSOed segments are freed, the packet is freed
automatically.

Signed-off-by: Jiayu Hu <jiayu.hu@intel.com>
Acked-by: Xiao Wang <xiao.w.wang@intel.com>
2018-07-11 23:45:20 +02:00

82 lines
2.0 KiB
C

/* SPDX-License-Identifier: BSD-3-Clause
* Copyright(c) 2018 Intel Corporation
*/
#include "gso_common.h"
#include "gso_udp4.h"
#define IPV4_HDR_MF_BIT (1U << 13)
static inline void
update_ipv4_udp_headers(struct rte_mbuf *pkt, struct rte_mbuf **segs,
uint16_t nb_segs)
{
struct ipv4_hdr *ipv4_hdr;
uint16_t frag_offset = 0, is_mf;
uint16_t l2_hdrlen = pkt->l2_len, l3_hdrlen = pkt->l3_len;
uint16_t tail_idx = nb_segs - 1, length, i;
/*
* Update IP header fields for output segments. Specifically,
* keep the same IP id, update fragment offset and total
* length.
*/
for (i = 0; i < nb_segs; i++) {
ipv4_hdr = rte_pktmbuf_mtod_offset(segs[i], struct ipv4_hdr *,
l2_hdrlen);
length = segs[i]->pkt_len - l2_hdrlen;
ipv4_hdr->total_length = rte_cpu_to_be_16(length);
is_mf = i < tail_idx ? IPV4_HDR_MF_BIT : 0;
ipv4_hdr->fragment_offset =
rte_cpu_to_be_16(frag_offset | is_mf);
frag_offset += ((length - l3_hdrlen) >> 3);
}
}
int
gso_udp4_segment(struct rte_mbuf *pkt,
uint16_t gso_size,
struct rte_mempool *direct_pool,
struct rte_mempool *indirect_pool,
struct rte_mbuf **pkts_out,
uint16_t nb_pkts_out)
{
struct ipv4_hdr *ipv4_hdr;
uint16_t pyld_unit_size, hdr_offset;
uint16_t frag_off;
int ret;
/* Don't process the fragmented packet */
ipv4_hdr = rte_pktmbuf_mtod_offset(pkt, struct ipv4_hdr *,
pkt->l2_len);
frag_off = rte_be_to_cpu_16(ipv4_hdr->fragment_offset);
if (unlikely(IS_FRAGMENTED(frag_off))) {
pkts_out[0] = pkt;
return 1;
}
/*
* UDP fragmentation is the same as IP fragmentation.
* Except the first one, other output packets just have l2
* and l3 headers.
*/
hdr_offset = pkt->l2_len + pkt->l3_len;
/* Don't process the packet without data. */
if (unlikely(hdr_offset + pkt->l4_len >= pkt->pkt_len)) {
pkts_out[0] = pkt;
return 1;
}
pyld_unit_size = gso_size - hdr_offset;
/* Segment the payload */
ret = gso_do_segment(pkt, hdr_offset, pyld_unit_size, direct_pool,
indirect_pool, pkts_out, nb_pkts_out);
if (ret > 1)
update_ipv4_udp_headers(pkt, pkts_out, ret);
return ret;
}