lib/gso/gso_udp4.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2018 Intel Corporation
   3  */
   4
   5 #include "gso_common.h"
   6 #include "gso_udp4.h"
   7
   8 #define IPV4_HDR_MF_BIT (1U << 13)
   9
  10 static inline void
  11 update_ipv4_udp_headers(struct rte_mbuf *pkt, struct rte_mbuf **segs,
  12                 uint16_t nb_segs)
  13 {
  14         struct rte_ipv4_hdr *ipv4_hdr;
  15         uint16_t frag_offset = 0, is_mf;
  16         uint16_t l2_hdrlen = pkt->l2_len, l3_hdrlen = pkt->l3_len;
  17         uint16_t tail_idx = nb_segs - 1, length, i;
  18
  19         /*
  20          * Update IP header fields for output segments. Specifically,
  21          * keep the same IP id, update fragment offset and total
  22          * length.
  23          */
  24         for (i = 0; i < nb_segs; i++) {
  25                 ipv4_hdr = rte_pktmbuf_mtod_offset(segs[i],
  26                         struct rte_ipv4_hdr *, l2_hdrlen);
  27                 length = segs[i]->pkt_len - l2_hdrlen;
  28                 ipv4_hdr->total_length = rte_cpu_to_be_16(length);
  29
  30                 is_mf = i < tail_idx ? IPV4_HDR_MF_BIT : 0;
  31                 ipv4_hdr->fragment_offset =
  32                         rte_cpu_to_be_16(frag_offset | is_mf);
  33                 frag_offset += ((length - l3_hdrlen) >> 3);
  34         }
  35 }
  36
  37 int
  38 gso_udp4_segment(struct rte_mbuf *pkt,
  39                 uint16_t gso_size,
  40                 struct rte_mempool *direct_pool,
  41                 struct rte_mempool *indirect_pool,
  42                 struct rte_mbuf **pkts_out,
  43                 uint16_t nb_pkts_out)
  44 {
  45         struct rte_ipv4_hdr *ipv4_hdr;
  46         uint16_t pyld_unit_size, hdr_offset;
  47         uint16_t frag_off;
  48         int ret;
  49
  50         /* Don't process the fragmented packet */
  51         ipv4_hdr = rte_pktmbuf_mtod_offset(pkt, struct rte_ipv4_hdr *,
  52                         pkt->l2_len);
  53         frag_off = rte_be_to_cpu_16(ipv4_hdr->fragment_offset);
  54         if (unlikely(IS_FRAGMENTED(frag_off))) {
  55                 return 0;
  56         }
  57
  58         /*
  59          * UDP fragmentation is the same as IP fragmentation.
  60          * Except the first one, other output packets just have l2
  61          * and l3 headers.
  62          */
  63         hdr_offset = pkt->l2_len + pkt->l3_len;
  64
  65         /* Don't process the packet without data. */
  66         if (unlikely(hdr_offset + pkt->l4_len >= pkt->pkt_len)) {
  67                 return 0;
  68         }
  69
  70         /* pyld_unit_size must be a multiple of 8 because frag_off
  71          * uses 8 bytes as unit.
  72          */
  73         pyld_unit_size = (gso_size - hdr_offset) & ~7U;
  74
  75         /* Segment the payload */
  76         ret = gso_do_segment(pkt, hdr_offset, pyld_unit_size, direct_pool,
  77                         indirect_pool, pkts_out, nb_pkts_out);
  78         if (ret > 1)
  79                 update_ipv4_udp_headers(pkt, pkts_out, ret);
  80
  81         return ret;
  82 }