ceph/src/seastar/dpdk/lib/librte_ip_frag/rte_ipv6_reassembly.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2014 Intel Corporation
   3  */
   4
   5 #include <stddef.h>
   6
   7 #include <rte_memcpy.h>
   8
   9 #include "ip_frag_common.h"
  10
  11 /**
  12  * @file
  13  * IPv6 reassemble
  14  *
  15  * Implementation of IPv6 reassembly.
  16  *
  17  */
  18
  19 static inline void
  20 ip_frag_memmove(char *dst, char *src, int len)
  21 {
  22         int i;
  23
  24         /* go backwards to make sure we don't overwrite anything important */
  25         for (i = len - 1; i >= 0; i--)
  26                 dst[i] = src[i];
  27 }
  28
  29 /*
  30  * Reassemble fragments into one packet.
  31  */
  32 struct rte_mbuf *
  33 ipv6_frag_reassemble(struct ip_frag_pkt *fp)
  34 {
  35         struct ipv6_hdr *ip_hdr;
  36         struct ipv6_extension_fragment *frag_hdr;
  37         struct rte_mbuf *m, *prev;
  38         uint32_t i, n, ofs, first_len;
  39         uint32_t last_len, move_len, payload_len;
  40         uint32_t curr_idx = 0;
  41
  42         first_len = fp->frags[IP_FIRST_FRAG_IDX].len;
  43         n = fp->last_idx - 1;
  44
  45         /*start from the last fragment. */
  46         m = fp->frags[IP_LAST_FRAG_IDX].mb;
  47         ofs = fp->frags[IP_LAST_FRAG_IDX].ofs;
  48         last_len = fp->frags[IP_LAST_FRAG_IDX].len;
  49         curr_idx = IP_LAST_FRAG_IDX;
  50
  51         payload_len = ofs + last_len;
  52
  53         while (ofs != first_len) {
  54
  55                 prev = m;
  56
  57                 for (i = n; i != IP_FIRST_FRAG_IDX && ofs != first_len; i--) {
  58
  59                         /* previous fragment found. */
  60                         if (fp->frags[i].ofs + fp->frags[i].len == ofs) {
  61
  62                                 RTE_ASSERT(curr_idx != i);
  63
  64                                 /* adjust start of the last fragment data. */
  65                                 rte_pktmbuf_adj(m,
  66                                         (uint16_t)(m->l2_len + m->l3_len));
  67                                 rte_pktmbuf_chain(fp->frags[i].mb, m);
  68
  69                                 /* this mbuf should not be accessed directly */
  70                                 fp->frags[curr_idx].mb = NULL;
  71                                 curr_idx = i;
  72
  73                                 /* update our last fragment and offset. */
  74                                 m = fp->frags[i].mb;
  75                                 ofs = fp->frags[i].ofs;
  76                         }
  77                 }
  78
  79                 /* error - hole in the packet. */
  80                 if (m == prev) {
  81                         return NULL;
  82                 }
  83         }
  84
  85         /* chain with the first fragment. */
  86         rte_pktmbuf_adj(m, (uint16_t)(m->l2_len + m->l3_len));
  87         rte_pktmbuf_chain(fp->frags[IP_FIRST_FRAG_IDX].mb, m);
  88         fp->frags[curr_idx].mb = NULL;
  89         m = fp->frags[IP_FIRST_FRAG_IDX].mb;
  90         fp->frags[IP_FIRST_FRAG_IDX].mb = NULL;
  91
  92         /* update mbuf fields for reassembled packet. */
  93         m->ol_flags |= PKT_TX_IP_CKSUM;
  94
  95         /* update ipv6 header for the reassembled datagram */
  96         ip_hdr = rte_pktmbuf_mtod_offset(m, struct ipv6_hdr *, m->l2_len);
  97
  98         ip_hdr->payload_len = rte_cpu_to_be_16(payload_len);
  99
 100         /*
 101          * remove fragmentation header. note that per RFC2460, we need to update
 102          * the last non-fragmentable header with the "next header" field to contain
 103          * type of the first fragmentable header, but we currently don't support
 104          * other headers, so we assume there are no other headers and thus update
 105          * the main IPv6 header instead.
 106          */
 107         move_len = m->l2_len + m->l3_len - sizeof(*frag_hdr);
 108         frag_hdr = (struct ipv6_extension_fragment *) (ip_hdr + 1);
 109         ip_hdr->proto = frag_hdr->next_header;
 110
 111         ip_frag_memmove(rte_pktmbuf_mtod_offset(m, char *, sizeof(*frag_hdr)),
 112                         rte_pktmbuf_mtod(m, char*), move_len);
 113
 114         rte_pktmbuf_adj(m, sizeof(*frag_hdr));
 115
 116         return m;
 117 }
 118
 119 /*
 120  * Process new mbuf with fragment of IPV6 datagram.
 121  * Incoming mbuf should have its l2_len/l3_len fields setup correctly.
 122  * @param tbl
 123  *   Table where to lookup/add the fragmented packet.
 124  * @param mb
 125  *   Incoming mbuf with IPV6 fragment.
 126  * @param tms
 127  *   Fragment arrival timestamp.
 128  * @param ip_hdr
 129  *   Pointer to the IPV6 header.
 130  * @param frag_hdr
 131  *   Pointer to the IPV6 fragment extension header.
 132  * @return
 133  *   Pointer to mbuf for reassembled packet, or NULL if:
 134  *   - an error occurred.
 135  *   - not all fragments of the packet are collected yet.
 136  */
 137 #define MORE_FRAGS(x) (((x) & 0x100) >> 8)
 138 #define FRAG_OFFSET(x) (rte_cpu_to_be_16(x) >> 3)
 139 struct rte_mbuf *
 140 rte_ipv6_frag_reassemble_packet(struct rte_ip_frag_tbl *tbl,
 141         struct rte_ip_frag_death_row *dr, struct rte_mbuf *mb, uint64_t tms,
 142         struct ipv6_hdr *ip_hdr, struct ipv6_extension_fragment *frag_hdr)
 143 {
 144         struct ip_frag_pkt *fp;
 145         struct ip_frag_key key;
 146         uint16_t ip_ofs;
 147         int32_t ip_len;
 148
 149         rte_memcpy(&key.src_dst[0], ip_hdr->src_addr, 16);
 150         rte_memcpy(&key.src_dst[2], ip_hdr->dst_addr, 16);
 151
 152         key.id = frag_hdr->id;
 153         key.key_len = IPV6_KEYLEN;
 154
 155         ip_ofs = FRAG_OFFSET(frag_hdr->frag_data) * 8;
 156
 157         /*
 158          * as per RFC2460, payload length contains all extension headers
 159          * as well.
 160          * since we don't support anything but frag headers,
 161          * this is what we remove from the payload len.
 162          */
 163         ip_len = rte_be_to_cpu_16(ip_hdr->payload_len) - sizeof(*frag_hdr);
 164
 165         IP_FRAG_LOG(DEBUG, "%s:%d:\n"
 166                 "mbuf: %p, tms: %" PRIu64
 167                 ", key: <" IPv6_KEY_BYTES_FMT ", %#x>, "
 168                 "ofs: %u, len: %d, flags: %#x\n"
 169                 "tbl: %p, max_cycles: %" PRIu64 ", entry_mask: %#x, "
 170                 "max_entries: %u, use_entries: %u\n\n",
 171                 __func__, __LINE__,
 172                 mb, tms, IPv6_KEY_BYTES(key.src_dst), key.id, ip_ofs, ip_len,
 173                 RTE_IPV6_GET_MF(frag_hdr->frag_data),
 174                 tbl, tbl->max_cycles, tbl->entry_mask, tbl->max_entries,
 175                 tbl->use_entries);
 176
 177         /* check that fragment length is greater then zero. */
 178         if (ip_len <= 0) {
 179                 IP_FRAG_MBUF2DR(dr, mb);
 180                 return NULL;
 181         }
 182
 183         /* try to find/add entry into the fragment's table. */
 184         fp = ip_frag_find(tbl, dr, &key, tms);
 185         if (fp == NULL) {
 186                 IP_FRAG_MBUF2DR(dr, mb);
 187                 return NULL;
 188         }
 189
 190         IP_FRAG_LOG(DEBUG, "%s:%d:\n"
 191                 "tbl: %p, max_entries: %u, use_entries: %u\n"
 192                 "ipv6_frag_pkt: %p, key: <" IPv6_KEY_BYTES_FMT ", %#x>, start: %" PRIu64
 193                 ", total_size: %u, frag_size: %u, last_idx: %u\n\n",
 194                 __func__, __LINE__,
 195                 tbl, tbl->max_entries, tbl->use_entries,
 196                 fp, IPv6_KEY_BYTES(fp->key.src_dst), fp->key.id, fp->start,
 197                 fp->total_size, fp->frag_size, fp->last_idx);
 198
 199
 200         /* process the fragmented packet. */
 201         mb = ip_frag_process(fp, dr, mb, ip_ofs, ip_len,
 202                         MORE_FRAGS(frag_hdr->frag_data));
 203         ip_frag_inuse(tbl, fp);
 204
 205         IP_FRAG_LOG(DEBUG, "%s:%d:\n"
 206                 "mbuf: %p\n"
 207                 "tbl: %p, max_entries: %u, use_entries: %u\n"
 208                 "ipv6_frag_pkt: %p, key: <" IPv6_KEY_BYTES_FMT ", %#x>, start: %" PRIu64
 209                 ", total_size: %u, frag_size: %u, last_idx: %u\n\n",
 210                 __func__, __LINE__, mb,
 211                 tbl, tbl->max_entries, tbl->use_entries,
 212                 fp, IPv6_KEY_BYTES(fp->key.src_dst), fp->key.id, fp->start,
 213                 fp->total_size, fp->frag_size, fp->last_idx);
 214
 215         return mb;
 216 }