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/* SPDX-License-Identifier: BSD-3-Clause
* Copyright(c) 2010-2014 Intel Corporation
*/
#include <stddef.h>
#include <errno.h>
#include <rte_memcpy.h>
#include <rte_mempool.h>
#include <rte_debug.h>
#include "ip_frag_common.h"
/* Fragment Offset */
#define IPV4_HDR_DF_SHIFT 14
#define IPV4_HDR_MF_SHIFT 13
#define IPV4_HDR_FO_SHIFT 3
#define IPV4_HDR_DF_MASK (1 << IPV4_HDR_DF_SHIFT)
#define IPV4_HDR_MF_MASK (1 << IPV4_HDR_MF_SHIFT)
#define IPV4_HDR_FO_ALIGN (1 << IPV4_HDR_FO_SHIFT)
static inline void __fill_ipv4hdr_frag(struct ipv4_hdr *dst,
const struct ipv4_hdr *src, uint16_t len, uint16_t fofs,
uint16_t dofs, uint32_t mf)
{
rte_memcpy(dst, src, sizeof(*dst));
fofs = (uint16_t)(fofs + (dofs >> IPV4_HDR_FO_SHIFT));
fofs = (uint16_t)(fofs | mf << IPV4_HDR_MF_SHIFT);
dst->fragment_offset = rte_cpu_to_be_16(fofs);
dst->total_length = rte_cpu_to_be_16(len);
dst->hdr_checksum = 0;
}
static inline void __free_fragments(struct rte_mbuf *mb[], uint32_t num)
{
uint32_t i;
for (i = 0; i != num; i++)
rte_pktmbuf_free(mb[i]);
}
/**
* IPv4 fragmentation.
*
* This function implements the fragmentation of IPv4 packets.
*
* @param pkt_in
* The input packet.
* @param pkts_out
* Array storing the output fragments.
* @param mtu_size
* Size in bytes of the Maximum Transfer Unit (MTU) for the outgoing IPv4
* datagrams. This value includes the size of the IPv4 header.
* @param pool_direct
* MBUF pool used for allocating direct buffers for the output fragments.
* @param pool_indirect
* MBUF pool used for allocating indirect buffers for the output fragments.
* @return
* Upon successful completion - number of output fragments placed
* in the pkts_out array.
* Otherwise - (-1) * <errno>.
*/
int32_t
rte_ipv4_fragment_packet(struct rte_mbuf *pkt_in,
struct rte_mbuf **pkts_out,
uint16_t nb_pkts_out,
uint16_t mtu_size,
struct rte_mempool *pool_direct,
struct rte_mempool *pool_indirect)
{
struct rte_mbuf *in_seg = NULL;
struct ipv4_hdr *in_hdr;
uint32_t out_pkt_pos, in_seg_data_pos;
uint32_t more_in_segs;
uint16_t fragment_offset, flag_offset, frag_size;
uint16_t frag_bytes_remaining;
/*
* Ensure the IP payload length of all fragments is aligned to a
* multiple of 8 bytes as per RFC791 section 2.3.
*/
frag_size = RTE_ALIGN_FLOOR((mtu_size - sizeof(struct ipv4_hdr)),
IPV4_HDR_FO_ALIGN);
in_hdr = rte_pktmbuf_mtod(pkt_in, struct ipv4_hdr *);
flag_offset = rte_cpu_to_be_16(in_hdr->fragment_offset);
/* If Don't Fragment flag is set */
if (unlikely ((flag_offset & IPV4_HDR_DF_MASK) != 0))
return -ENOTSUP;
/* Check that pkts_out is big enough to hold all fragments */
if (unlikely(frag_size * nb_pkts_out <
(uint16_t)(pkt_in->pkt_len - sizeof (struct ipv4_hdr))))
return -EINVAL;
in_seg = pkt_in;
in_seg_data_pos = sizeof(struct ipv4_hdr);
out_pkt_pos = 0;
fragment_offset = 0;
more_in_segs = 1;
while (likely(more_in_segs)) {
struct rte_mbuf *out_pkt = NULL, *out_seg_prev = NULL;
uint32_t more_out_segs;
struct ipv4_hdr *out_hdr;
/* Allocate direct buffer */
out_pkt = rte_pktmbuf_alloc(pool_direct);
if (unlikely(out_pkt == NULL)) {
__free_fragments(pkts_out, out_pkt_pos);
return -ENOMEM;
}
/* Reserve space for the IP header that will be built later */
out_pkt->data_len = sizeof(struct ipv4_hdr);
out_pkt->pkt_len = sizeof(struct ipv4_hdr);
frag_bytes_remaining = frag_size;
out_seg_prev = out_pkt;
more_out_segs = 1;
while (likely(more_out_segs && more_in_segs)) {
struct rte_mbuf *out_seg = NULL;
uint32_t len;
/* Allocate indirect buffer */
out_seg = rte_pktmbuf_alloc(pool_indirect);
if (unlikely(out_seg == NULL)) {
rte_pktmbuf_free(out_pkt);
__free_fragments(pkts_out, out_pkt_pos);
return -ENOMEM;
}
out_seg_prev->next = out_seg;
out_seg_prev = out_seg;
/* Prepare indirect buffer */
rte_pktmbuf_attach(out_seg, in_seg);
len = frag_bytes_remaining;
if (len > (in_seg->data_len - in_seg_data_pos)) {
len = in_seg->data_len - in_seg_data_pos;
}
out_seg->data_off = in_seg->data_off + in_seg_data_pos;
out_seg->data_len = (uint16_t)len;
out_pkt->pkt_len = (uint16_t)(len +
out_pkt->pkt_len);
out_pkt->nb_segs += 1;
in_seg_data_pos += len;
frag_bytes_remaining -= len;
/* Current output packet (i.e. fragment) done ? */
if (unlikely(frag_bytes_remaining == 0))
more_out_segs = 0;
/* Current input segment done ? */
if (unlikely(in_seg_data_pos == in_seg->data_len)) {
in_seg = in_seg->next;
in_seg_data_pos = 0;
if (unlikely(in_seg == NULL))
more_in_segs = 0;
}
}
/* Build the IP header */
out_hdr = rte_pktmbuf_mtod(out_pkt, struct ipv4_hdr *);
__fill_ipv4hdr_frag(out_hdr, in_hdr,
(uint16_t)out_pkt->pkt_len,
flag_offset, fragment_offset, more_in_segs);
fragment_offset = (uint16_t)(fragment_offset +
out_pkt->pkt_len - sizeof(struct ipv4_hdr));
out_pkt->ol_flags |= PKT_TX_IP_CKSUM;
out_pkt->l3_len = sizeof(struct ipv4_hdr);
/* Write the fragment to the output list */
pkts_out[out_pkt_pos] = out_pkt;
out_pkt_pos ++;
}
return out_pkt_pos;
}
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