lib/librte_ip_frag/rte_ipv6_fragmentation.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2014 Intel Corporation
   3  */
   4
   5 #include <stddef.h>
   6 #include <errno.h>
   7
   8 #include <rte_memcpy.h>
   9
  10 #include "ip_frag_common.h"
  11
  12 /**
  13  * @file
  14  * RTE IPv6 Fragmentation
  15  *
  16  * Implementation of IPv6 fragmentation.
  17  *
  18  */
  19
  20 static inline void
  21 __fill_ipv6hdr_frag(struct rte_ipv6_hdr *dst,
  22                 const struct rte_ipv6_hdr *src, uint16_t len, uint16_t fofs,
  23                 uint32_t mf)
  24 {
  25         struct ipv6_extension_fragment *fh;
  26
  27         rte_memcpy(dst, src, sizeof(*dst));
  28         dst->payload_len = rte_cpu_to_be_16(len);
  29         dst->proto = IPPROTO_FRAGMENT;
  30
  31         fh = (struct ipv6_extension_fragment *) ++dst;
  32         fh->next_header = src->proto;
  33         fh->reserved = 0;
  34         fh->frag_data = rte_cpu_to_be_16(RTE_IPV6_SET_FRAG_DATA(fofs, mf));
  35         fh->id = 0;
  36 }
  37
  38 static inline void
  39 __free_fragments(struct rte_mbuf *mb[], uint32_t num)
  40 {
  41         uint32_t i;
  42         for (i = 0; i < num; i++)
  43                 rte_pktmbuf_free(mb[i]);
  44 }
  45
  46 /**
  47  * IPv6 fragmentation.
  48  *
  49  * This function implements the fragmentation of IPv6 packets.
  50  *
  51  * @param pkt_in
  52  *   The input packet.
  53  * @param pkts_out
  54  *   Array storing the output fragments.
  55  * @param mtu_size
  56  *   Size in bytes of the Maximum Transfer Unit (MTU) for the outgoing IPv6
  57  *   datagrams. This value includes the size of the IPv6 header.
  58  * @param pool_direct
  59  *   MBUF pool used for allocating direct buffers for the output fragments.
  60  * @param pool_indirect
  61  *   MBUF pool used for allocating indirect buffers for the output fragments.
  62  * @return
  63  *   Upon successful completion - number of output fragments placed
  64  *   in the pkts_out array.
  65  *   Otherwise - (-1) * <errno>.
  66  */
  67 int32_t
  68 rte_ipv6_fragment_packet(struct rte_mbuf *pkt_in,
  69         struct rte_mbuf **pkts_out,
  70         uint16_t nb_pkts_out,
  71         uint16_t mtu_size,
  72         struct rte_mempool *pool_direct,
  73         struct rte_mempool *pool_indirect)
  74 {
  75         struct rte_mbuf *in_seg = NULL;
  76         struct rte_ipv6_hdr *in_hdr;
  77         uint32_t out_pkt_pos, in_seg_data_pos;
  78         uint32_t more_in_segs;
  79         uint16_t fragment_offset, frag_size;
  80         uint64_t frag_bytes_remaining;
  81
  82         /*
  83          * Ensure the IP payload length of all fragments (except the
  84          * the last fragment) are a multiple of 8 bytes per RFC2460.
  85          */
  86         frag_size = RTE_ALIGN_FLOOR(mtu_size - sizeof(struct rte_ipv6_hdr),
  87                                     RTE_IPV6_EHDR_FO_ALIGN);
  88
  89         /* Check that pkts_out is big enough to hold all fragments */
  90         if (unlikely (frag_size * nb_pkts_out <
  91             (uint16_t)(pkt_in->pkt_len - sizeof(struct rte_ipv6_hdr))))
  92                 return -EINVAL;
  93
  94         in_hdr = rte_pktmbuf_mtod(pkt_in, struct rte_ipv6_hdr *);
  95
  96         in_seg = pkt_in;
  97         in_seg_data_pos = sizeof(struct rte_ipv6_hdr);
  98         out_pkt_pos = 0;
  99         fragment_offset = 0;
 100
 101         more_in_segs = 1;
 102         while (likely(more_in_segs)) {
 103                 struct rte_mbuf *out_pkt = NULL, *out_seg_prev = NULL;
 104                 uint32_t more_out_segs;
 105                 struct rte_ipv6_hdr *out_hdr;
 106
 107                 /* Allocate direct buffer */
 108                 out_pkt = rte_pktmbuf_alloc(pool_direct);
 109                 if (unlikely(out_pkt == NULL)) {
 110                         __free_fragments(pkts_out, out_pkt_pos);
 111                         return -ENOMEM;
 112                 }
 113
 114                 /* Reserve space for the IP header that will be built later */
 115                 out_pkt->data_len = sizeof(struct rte_ipv6_hdr) +
 116                         sizeof(struct ipv6_extension_fragment);
 117                 out_pkt->pkt_len  = sizeof(struct rte_ipv6_hdr) +
 118                         sizeof(struct ipv6_extension_fragment);
 119                 frag_bytes_remaining = frag_size;
 120
 121                 out_seg_prev = out_pkt;
 122                 more_out_segs = 1;
 123                 while (likely(more_out_segs && more_in_segs)) {
 124                         struct rte_mbuf *out_seg = NULL;
 125                         uint32_t len;
 126
 127                         /* Allocate indirect buffer */
 128                         out_seg = rte_pktmbuf_alloc(pool_indirect);
 129                         if (unlikely(out_seg == NULL)) {
 130                                 rte_pktmbuf_free(out_pkt);
 131                                 __free_fragments(pkts_out, out_pkt_pos);
 132                                 return -ENOMEM;
 133                         }
 134                         out_seg_prev->next = out_seg;
 135                         out_seg_prev = out_seg;
 136
 137                         /* Prepare indirect buffer */
 138                         rte_pktmbuf_attach(out_seg, in_seg);
 139                         len = frag_bytes_remaining;
 140                         if (len > (in_seg->data_len - in_seg_data_pos)) {
 141                                 len = in_seg->data_len - in_seg_data_pos;
 142                         }
 143                         out_seg->data_off = in_seg->data_off + in_seg_data_pos;
 144                         out_seg->data_len = (uint16_t)len;
 145                         out_pkt->pkt_len = (uint16_t)(len +
 146                             out_pkt->pkt_len);
 147                         out_pkt->nb_segs += 1;
 148                         in_seg_data_pos += len;
 149                         frag_bytes_remaining -= len;
 150
 151                         /* Current output packet (i.e. fragment) done ? */
 152                         if (unlikely(frag_bytes_remaining == 0))
 153                                 more_out_segs = 0;
 154
 155                         /* Current input segment done ? */
 156                         if (unlikely(in_seg_data_pos == in_seg->data_len)) {
 157                                 in_seg = in_seg->next;
 158                                 in_seg_data_pos = 0;
 159
 160                                 if (unlikely(in_seg == NULL)) {
 161                                         more_in_segs = 0;
 162                                 }
 163                         }
 164                 }
 165
 166                 /* Build the IP header */
 167
 168                 out_hdr = rte_pktmbuf_mtod(out_pkt, struct rte_ipv6_hdr *);
 169
 170                 __fill_ipv6hdr_frag(out_hdr, in_hdr,
 171                     (uint16_t) out_pkt->pkt_len - sizeof(struct rte_ipv6_hdr),
 172                     fragment_offset, more_in_segs);
 173
 174                 fragment_offset = (uint16_t)(fragment_offset +
 175                     out_pkt->pkt_len - sizeof(struct rte_ipv6_hdr)
 176                         - sizeof(struct ipv6_extension_fragment));
 177
 178                 /* Write the fragment to the output list */
 179                 pkts_out[out_pkt_pos] = out_pkt;
 180                 out_pkt_pos ++;
 181         }
 182
 183         return out_pkt_pos;
 184 }