text: /*
   * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2016 Nicira, Inc.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at:
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include <config.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include "dp-packet.h"
  #include "netdev-afxdp.h"
  #include "netdev-dpdk.h"
  #include "openvswitch/dynamic-string.h"
  #include "util.h"
  
  static void
  dp_packet_init__(struct dp_packet *b, size_t allocated, enum dp_packet_source source)
  {
      dp_packet_set_allocated(b, allocated);
      b->source = source;
      dp_packet_reset_offsets(b);
      pkt_metadata_init(&b->md, 0);
      dp_packet_reset_cutlen(b);
      dp_packet_reset_offload(b);
      /* Initialize implementation-specific fields of dp_packet. */
      dp_packet_init_specific(b);
      /* By default assume the packet type to be Ethernet. */
      b->packet_type = htonl(PT_ETH);
  }
  
  static void
  dp_packet_use__(struct dp_packet *b, void *base, size_t allocated,
               enum dp_packet_source source)
  {
      dp_packet_set_base(b, base);
      dp_packet_set_data(b, base);
      dp_packet_set_size(b, 0);
  
      dp_packet_init__(b, allocated, source);
  }
  
  /* Initializes 'b' as an empty dp_packet that contains the 'allocated' bytes of
   * memory starting at 'base'.  'base' should be the first byte of a region
   * obtained from malloc().  It will be freed (with free()) if 'b' is resized or
   * freed. */
  void
  dp_packet_use(struct dp_packet *b, void *base, size_t allocated)
  {
      dp_packet_use__(b, base, allocated, DPBUF_MALLOC);
  }
  
  #if HAVE_AF_XDP
  /* Initialize 'b' as an empty dp_packet that contains
   * memory starting at AF_XDP umem base.
   */
  void
  dp_packet_use_afxdp(struct dp_packet *b, void *data, size_t allocated,
                      size_t headroom)
  {
      dp_packet_set_base(b, (char *)data - headroom);
      dp_packet_set_data(b, data);
      dp_packet_set_size(b, 0);
  
      dp_packet_init__(b, allocated, DPBUF_AFXDP);
  }
  #endif
  
  /* Initializes 'b' as an empty dp_packet that contains the 'allocated' bytes of
   * memory starting at 'base'.  'base' should point to a buffer on the stack.
   * (Nothing actually relies on 'base' being allocated on the stack.  It could
   * be static or malloc()'d memory.  But stack space is the most common use
   * case.)
   *
   * 'base' should be appropriately aligned.  Using an array of uint32_t or
   * uint64_t for the buffer is a reasonable way to ensure appropriate alignment
   * for 32- or 64-bit data.
   *
   * An dp_packet operation that requires reallocating data will copy the provided
   * buffer into a malloc()'d buffer.  Thus, it is wise to call dp_packet_uninit()
   * on an dp_packet initialized by this function, so that if it expanded into the
   * heap, that memory is freed. */
  void
  dp_packet_use_stub(struct dp_packet *b, void *base, size_t allocated)
  {
      dp_packet_use__(b, base, allocated, DPBUF_STUB);
  }
  
  /* Initializes 'b' as an dp_packet whose data starts at 'data' and continues for
   * 'size' bytes.  This is appropriate for an dp_packet that will be used to
   * inspect existing data, without moving it around or reallocating it, and
   * generally without modifying it at all.
   *
   * An dp_packet operation that requires reallocating data will assert-fail if this
   * function was used to initialize it. */
  void
  dp_packet_use_const(struct dp_packet *b, const void *data, size_t size)
  {
      dp_packet_use__(b, CONST_CAST(void *, data), size, DPBUF_STACK);
      dp_packet_set_size(b, size);
  }
  
  /* Initializes 'b' as a DPDK dp-packet, which must have been allocated from a
   * DPDK memory pool. */
  void
  dp_packet_init_dpdk(struct dp_packet *b)
  {
      b->source = DPBUF_DPDK;
  }
  
  /* Initializes 'b' as an empty dp_packet with an initial capacity of 'size'
   * bytes. */
  void
  dp_packet_init(struct dp_packet *b, size_t size)
  {
      dp_packet_use(b, size ? xmalloc(size) : NULL, size);
  }
  
  /* Frees memory that 'b' points to. */
  void
  dp_packet_uninit(struct dp_packet *b)
  {
      if (b) {
          if (b->source == DPBUF_MALLOC) {
              free(dp_packet_base(b));
          } else if (b->source == DPBUF_DPDK) {
  #ifdef DPDK_NETDEV
              /* If this dp_packet was allocated by DPDK it must have been
               * created as a dp_packet */
              free_dpdk_buf((struct dp_packet*) b);
  #endif
          } else if (b->source == DPBUF_AFXDP) {
              free_afxdp_buf(b);
          }
      }
  }
  
  /* Creates and returns a new dp_packet with an initial capacity of 'size'
   * bytes. */
  struct dp_packet *
  dp_packet_new(size_t size)
  {
      struct dp_packet *b = xmalloc(sizeof *b);
      dp_packet_init(b, size);
      return b;
  }
  
  /* Creates and returns a new dp_packet with an initial capacity of 'size +
   * headroom' bytes, reserving the first 'headroom' bytes as headroom. */
  struct dp_packet *
  dp_packet_new_with_headroom(size_t size, size_t headroom)
  {
      struct dp_packet *b = dp_packet_new(size + headroom);
      dp_packet_reserve(b, headroom);
      return b;
  }
  
  /* Creates and returns a new dp_packet that initially contains a copy of the
   * 'dp_packet_size(buffer)' bytes of data starting at 'buffer->data' with no headroom or
   * tailroom. */
  struct dp_packet *
  dp_packet_clone(const struct dp_packet *buffer)
  {
      return dp_packet_clone_with_headroom(buffer, 0);
  }
  
  /* Creates and returns a new dp_packet whose data are copied from 'buffer'.
   * The returned dp_packet will additionally have 'headroom' bytes of
   * headroom. */
  struct dp_packet *
  dp_packet_clone_with_headroom(const struct dp_packet *buffer, size_t headroom)
  {
      struct dp_packet *new_buffer;
      uint32_t mark;
  
      new_buffer = dp_packet_clone_data_with_headroom(dp_packet_data(buffer),
                                                   dp_packet_size(buffer),
                                                   headroom);
      /* Copy the following fields into the returned buffer: l2_pad_size,
       * l2_5_ofs, l3_ofs, l4_ofs, cutlen, packet_type and md. */
      memcpy(&new_buffer->l2_pad_size, &buffer->l2_pad_size,
              sizeof(struct dp_packet) -
              offsetof(struct dp_packet, l2_pad_size));
  
      *dp_packet_ol_flags_ptr(new_buffer) = *dp_packet_ol_flags_ptr(buffer);
      *dp_packet_ol_flags_ptr(new_buffer) &= DP_PACKET_OL_SUPPORTED_MASK;
  
      if (dp_packet_rss_valid(buffer)) {
          dp_packet_set_rss_hash(new_buffer, dp_packet_get_rss_hash(buffer));
      }
      if (dp_packet_has_flow_mark(buffer, &mark)) {
          dp_packet_set_flow_mark(new_buffer, mark);
      }
  
      return new_buffer;
  }
  
  /* Creates and returns a new dp_packet that initially contains a copy of the
   * 'size' bytes of data starting at 'data' with no headroom or tailroom. */
  struct dp_packet *
  dp_packet_clone_data(const void *data, size_t size)
  {
      return dp_packet_clone_data_with_headroom(data, size, 0);
  }
  
  /* Creates and returns a new dp_packet that initially contains 'headroom' bytes of
   * headroom followed by a copy of the 'size' bytes of data starting at
   * 'data'. */
  struct dp_packet *
  dp_packet_clone_data_with_headroom(const void *data, size_t size, size_t headroom)
  {
      struct dp_packet *b = dp_packet_new_with_headroom(size, headroom);
      dp_packet_put(b, data, size);
      return b;
  }
  
  static void
  dp_packet_copy__(struct dp_packet *b, uint8_t *new_base,
                size_t new_headroom, size_t new_tailroom)
  {
      const uint8_t *old_base = dp_packet_base(b);
      size_t old_headroom = dp_packet_headroom(b);
      size_t old_tailroom = dp_packet_tailroom(b);
      size_t copy_headroom = MIN(old_headroom, new_headroom);
      size_t copy_tailroom = MIN(old_tailroom, new_tailroom);
  
      memcpy(&new_base[new_headroom - copy_headroom],
             &old_base[old_headroom - copy_headroom],
             copy_headroom + dp_packet_size(b) + copy_tailroom);
  }
  
  /* Reallocates 'b' so that it has exactly 'new_headroom' and 'new_tailroom'
   * bytes of headroom and tailroom, respectively. */
  void
  dp_packet_resize(struct dp_packet *b, size_t new_headroom, size_t new_tailroom)
  {
      void *new_base, *new_data;
      size_t new_allocated;
  
      new_allocated = new_headroom + dp_packet_size(b) + new_tailroom;
  
      switch (b->source) {
      case DPBUF_DPDK:
          OVS_NOT_REACHED();
  
      case DPBUF_MALLOC:
          if (new_headroom == dp_packet_headroom(b)) {
              new_base = xrealloc(dp_packet_base(b), new_allocated);
          } else {
              new_base = xmalloc(new_allocated);
              dp_packet_copy__(b, new_base, new_headroom, new_tailroom);
              free(dp_packet_base(b));
          }
          break;
  
      case DPBUF_STACK:
          OVS_NOT_REACHED();
  
      case DPBUF_AFXDP:
          OVS_NOT_REACHED();
  
      case DPBUF_STUB:
          b->source = DPBUF_MALLOC;
          new_base = xmalloc(new_allocated);
          dp_packet_copy__(b, new_base, new_headroom, new_tailroom);
          break;
  
      default:
          OVS_NOT_REACHED();
      }
  
      dp_packet_set_allocated(b, new_allocated);
      dp_packet_set_base(b, new_base);
  
      new_data = (char *) new_base + new_headroom;
      if (dp_packet_data(b) != new_data) {
          dp_packet_set_data(b, new_data);
      }
  }
  
  /* Ensures that 'b' has room for at least 'size' bytes at its tail end,
   * reallocating and copying its data if necessary.  Its headroom, if any, is
   * preserved. */
  void
  dp_packet_prealloc_tailroom(struct dp_packet *b, size_t size)
  {
      if ((size && !dp_packet_base(b)) || (size > dp_packet_tailroom(b))) {
          dp_packet_resize(b, dp_packet_headroom(b), MAX(size, 64));
      }
  }
  
  /* Ensures that 'b' has room for at least 'size' bytes at its head,
   * reallocating and copying its data if necessary.  Its tailroom, if any, is
   * preserved. */
  void
  dp_packet_prealloc_headroom(struct dp_packet *b, size_t size)
  {
      if (size > dp_packet_headroom(b)) {
          dp_packet_resize(b, MAX(size, 64), dp_packet_tailroom(b));
      }
  }
  
  /* Shifts all of the data within the allocated space in 'b' by 'delta' bytes.
   * For example, a 'delta' of 1 would cause each byte of data to move one byte
   * forward (from address 'p' to 'p+1'), and a 'delta' of -1 would cause each
   * byte to move one byte backward (from 'p' to 'p-1'). */
  void
  dp_packet_shift(struct dp_packet *b, int delta)
  {
      ovs_assert(delta > 0 ? delta <= dp_packet_tailroom(b)
                 : delta < 0 ? -delta <= dp_packet_headroom(b)
                 : true);
  
      if (delta != 0) {
          char *dst = (char *) dp_packet_data(b) + delta;
          memmove(dst, dp_packet_data(b), dp_packet_size(b));
          dp_packet_set_data(b, dst);
      }
  }
  
  /* Appends 'size' bytes of data to the tail end of 'b', reallocating and
   * copying its data if necessary.  Returns a pointer to the first byte of the
   * new data, which is left uninitialized. */
  void *
  dp_packet_put_uninit(struct dp_packet *b, size_t size)
  {
      void *p;
      dp_packet_prealloc_tailroom(b, size);
      p = dp_packet_tail(b);
      dp_packet_set_size(b, dp_packet_size(b) + size);
      return p;
  }
  
  /* Appends 'size' zeroed bytes to the tail end of 'b'.  Data in 'b' is
   * reallocated and copied if necessary.  Returns a pointer to the first byte of
   * the data's location in the dp_packet. */
  void *
  dp_packet_put_zeros(struct dp_packet *b, size_t size)
  {
      void *dst = dp_packet_put_uninit(b, size);
      memset(dst, 0, size);
      return dst;
  }
  
  /* Appends the 'size' bytes of data in 'p' to the tail end of 'b'.  Data in 'b'
   * is reallocated and copied if necessary.  Returns a pointer to the first
   * byte of the data's location in the dp_packet. */
  void *
  dp_packet_put(struct dp_packet *b, const void *p, size_t size)
  {
      void *dst = dp_packet_put_uninit(b, size);
      memcpy(dst, p, size);
      return dst;
  }
  
  /* Parses as many pairs of hex digits as possible (possibly separated by
   * spaces) from the beginning of 's', appending bytes for their values to 'b'.
   * Returns the first character of 's' that is not the first of a pair of hex
   * digits.  If 'n' is nonnull, stores the number of bytes added to 'b' in
   * '*n'. */
  char *
  dp_packet_put_hex(struct dp_packet *b, const char *s, size_t *n)
  {
      size_t initial_size = dp_packet_size(b);
      for (;;) {
          uint8_t byte;
          bool ok;
  
          s += strspn(s, " \t\r\n");
          byte = hexits_value(s, 2, &ok);
          if (!ok) {
              if (n) {
                  *n = dp_packet_size(b) - initial_size;
              }
              return CONST_CAST(char *, s);
          }
  
          dp_packet_put(b, &byte, 1);
          s += 2;
      }
  }
  
  /* Reserves 'size' bytes of headroom so that they can be later allocated with
   * dp_packet_push_uninit() without reallocating the dp_packet. */
  void
  dp_packet_reserve(struct dp_packet *b, size_t size)
  {
      ovs_assert(!dp_packet_size(b));
      dp_packet_prealloc_tailroom(b, size);
      dp_packet_set_data(b, (char*)dp_packet_data(b) + size);
  }
  
  /* Reserves 'headroom' bytes at the head and 'tailroom' at the end so that
   * they can be later allocated with dp_packet_push_uninit() or
   * dp_packet_put_uninit() without reallocating the dp_packet. */
  void
  dp_packet_reserve_with_tailroom(struct dp_packet *b, size_t headroom,
                               size_t tailroom)
  {
      ovs_assert(!dp_packet_size(b));
      dp_packet_prealloc_tailroom(b, headroom + tailroom);
      dp_packet_set_data(b, (char*)dp_packet_data(b) + headroom);
  }
  
  /* Prefixes 'size' bytes to the head end of 'b', reallocating and copying its
   * data if necessary.  Returns a pointer to the first byte of the data's
   * location in the dp_packet.  The new data is left uninitialized. */
  void *
  dp_packet_push_uninit(struct dp_packet *b, size_t size)
  {
      dp_packet_prealloc_headroom(b, size);
      dp_packet_set_data(b, (char*)dp_packet_data(b) - size);
      dp_packet_set_size(b, dp_packet_size(b) + size);
      return dp_packet_data(b);
  }
  
  /* Prefixes 'size' zeroed bytes to the head end of 'b', reallocating and
   * copying its data if necessary.  Returns a pointer to the first byte of the
   * data's location in the dp_packet. */
  void *
  dp_packet_push_zeros(struct dp_packet *b, size_t size)
  {
      void *dst = dp_packet_push_uninit(b, size);
      memset(dst, 0, size);
      return dst;
  }
  
  /* Copies the 'size' bytes starting at 'p' to the head end of 'b', reallocating
   * and copying its data if necessary.  Returns a pointer to the first byte of
   * the data's location in the dp_packet. */
  void *
  dp_packet_push(struct dp_packet *b, const void *p, size_t size)
  {
      void *dst = dp_packet_push_uninit(b, size);
      memcpy(dst, p, size);
      return dst;
  }
  
  /* Returns the data in 'b' as a block of malloc()'d memory and frees the buffer
   * within 'b'.  (If 'b' itself was dynamically allocated, e.g. with
   * dp_packet_new(), then it should still be freed with, e.g., dp_packet_delete().) */
  void *
  dp_packet_steal_data(struct dp_packet *b)
  {
      void *p;
      ovs_assert(b->source != DPBUF_DPDK);
      ovs_assert(b->source != DPBUF_AFXDP);
  
      if (b->source == DPBUF_MALLOC && dp_packet_data(b) == dp_packet_base(b)) {
          p = dp_packet_data(b);
      } else {
          p = xmemdup(dp_packet_data(b), dp_packet_size(b));
          if (b->source == DPBUF_MALLOC) {
              free(dp_packet_base(b));
          }
      }
      dp_packet_set_base(b, NULL);
      dp_packet_set_data(b, NULL);
      return p;
  }
  
  static inline void
  dp_packet_adjust_layer_offset(uint16_t *offset, int increment)
  {
      if (*offset != UINT16_MAX) {
          *offset += increment;
      }
  }
  
  /* Adjust the size of the l2_5 portion of the dp_packet, updating the l2
   * pointer and the layer offsets.  The caller is responsible for
   * modifying the contents. */
  void *
  dp_packet_resize_l2_5(struct dp_packet *b, int increment)
  {
      if (increment >= 0) {
          dp_packet_push_uninit(b, increment);
      } else {
          dp_packet_pull(b, -increment);
      }
  
      /* Adjust layer offsets after l2_5. */
      dp_packet_adjust_layer_offset(&b->l3_ofs, increment);
      dp_packet_adjust_layer_offset(&b->l4_ofs, increment);
  
      return dp_packet_data(b);
  }
  
  /* Adjust the size of the l2 portion of the dp_packet, updating the l2
   * pointer and the layer offsets.  The caller is responsible for
   * modifying the contents. */
  void *
  dp_packet_resize_l2(struct dp_packet *b, int increment)
  {
      dp_packet_resize_l2_5(b, increment);
      dp_packet_adjust_layer_offset(&b->l2_5_ofs, increment);
      return dp_packet_data(b);
  }
  