ip6_packet.h

Go to the documentation of this file.

/*
 * Copyright (c) 2015 Cisco and/or its affiliates.
 * 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.
 */
/*
 * ip6/packet.h: ip6 packet format
 *
 * Copyright (c) 2008 Eliot Dresselhaus
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef included_ip6_packet_h
#define included_ip6_packet_h

#include <vnet/tcp/tcp_packet.h>
#include <vnet/ip/ip4_packet.h>

typedef union
{
  u8 as_u8[16];
  u16 as_u16[8];
  u32 as_u32[4];
  u64 as_u64[2];
  u64x2 as_u128;
  uword as_uword[16 / sizeof (uword)];
}
__clib_packed ip6_address_t;

STATIC_ASSERT_SIZEOF (ip6_address_t, 16);

typedef struct
{
  ip6_address_t addr, mask;
} ip6_address_and_mask_t;

/* Packed so that the mhash key doesn't include uninitialized pad bytes */
/* *INDENT-OFF* */
typedef CLIB_PACKED (struct {
  /* IP address must be first for ip_interface_address_get_address() to work */
  ip6_address_t ip6_addr;
  u32 fib_index;
}) ip6_address_fib_t;
/* *INDENT-ON* */

always_inline void
ip6_addr_fib_init (ip6_address_fib_t * addr_fib,
                   const ip6_address_t * address, u32 fib_index)
{
  addr_fib->ip6_addr = *address;
  addr_fib->fib_index = fib_index;
}

/* Special addresses:
   unspecified          ::/128
   loopback             ::1/128
   global unicast       2000::/3
   unique local unicast fc00::/7
   link local unicast   fe80::/10
   multicast            ff00::/8
   ietf reserved        everything else. */

#define foreach_ip6_multicast_address_scope     \
  _ (loopback, 0x1)                             \
  _ (link_local, 0x2)                           \
  _ (admin_local, 0x4)                          \
  _ (site_local, 0x5)                           \
  _ (organization_local, 0x8)                   \
  _ (global, 0xe)

#define foreach_ip6_multicast_link_local_group_id       \
  _ (all_hosts, 0x1)                                    \
  _ (all_routers, 0x2)                                  \
  _ (rip_routers, 0x9)                                  \
  _ (eigrp_routers, 0xa)                                \
  _ (pim_routers, 0xd)                            \
 _ (mldv2_routers, 0x16)

typedef enum
{
#define _(f,n) IP6_MULTICAST_SCOPE_##f = n,
  foreach_ip6_multicast_address_scope
#undef _
} ip6_multicast_address_scope_t;

typedef enum
{
#define _(f,n) IP6_MULTICAST_GROUP_ID_##f = n,
  foreach_ip6_multicast_link_local_group_id
#undef _
} ip6_multicast_link_local_group_id_t;

always_inline uword
ip6_address_is_multicast (const ip6_address_t * a)
{
  return a->as_u8[0] == 0xff;
}

always_inline void
ip6_address_copy (ip6_address_t * dst, const ip6_address_t * src)
{
  dst->as_u64[0] = src->as_u64[0];
  dst->as_u64[1] = src->as_u64[1];
}

always_inline void
ip6_set_reserved_multicast_address (ip6_address_t * a,
                                    ip6_multicast_address_scope_t scope,
                                    u16 id)
{
  a->as_u64[0] = a->as_u64[1] = 0;
  a->as_u16[0] = clib_host_to_net_u16 (0xff00 | scope);
  a->as_u16[7] = clib_host_to_net_u16 (id);
}

always_inline void
ip6_set_solicited_node_multicast_address (ip6_address_t * a, u32 id)
{
  /* 0xff02::1:ffXX:XXXX. */
  a->as_u64[0] = a->as_u64[1] = 0;
  a->as_u16[0] = clib_host_to_net_u16 (0xff02);
  a->as_u8[11] = 1;
  ASSERT ((id >> 24) == 0);
  id |= 0xff << 24;
  a->as_u32[3] = clib_host_to_net_u32 (id);
}

always_inline void
ip6_multicast_ethernet_address (u8 * ethernet_address, u32 group_id)
{
  ethernet_address[0] = 0x33;
  ethernet_address[1] = 0x33;
  ethernet_address[2] = ((group_id >> 24) & 0xff);
  ethernet_address[3] = ((group_id >> 16) & 0xff);
  ethernet_address[4] = ((group_id >> 8) & 0xff);
  ethernet_address[5] = ((group_id >> 0) & 0xff);
}

always_inline uword
ip6_address_is_equal (const ip6_address_t * a, const ip6_address_t * b)
{
  int i;
  for (i = 0; i < ARRAY_LEN (a->as_uword); i++)
    if (a->as_uword[i] != b->as_uword[i])
      return 0;
  return 1;
}

always_inline uword
ip6_address_is_equal_masked (const ip6_address_t * a,
                             const ip6_address_t * b,
                             const ip6_address_t * mask)
{
  int i;
  for (i = 0; i < ARRAY_LEN (a->as_uword); i++)
    {
      uword a_masked, b_masked;
      a_masked = a->as_uword[i] & mask->as_uword[i];
      b_masked = b->as_uword[i] & mask->as_uword[i];

      if (a_masked != b_masked)
        return 0;
    }
  return 1;
}

always_inline void
ip6_address_mask (ip6_address_t * a, const ip6_address_t * mask)
{
  int i;
  for (i = 0; i < ARRAY_LEN (a->as_uword); i++)
    a->as_uword[i] &= mask->as_uword[i];
}

always_inline void
ip6_address_set_zero (ip6_address_t * a)
{
  int i;
  for (i = 0; i < ARRAY_LEN (a->as_uword); i++)
    a->as_uword[i] = 0;
}

always_inline void
ip6_address_mask_from_width (ip6_address_t * a, u32 width)
{
  int i, byte, bit, bitnum;
  ASSERT (width <= 128);
  clib_memset (a, 0, sizeof (a[0]));
  for (i = 0; i < width; i++)
    {
      bitnum = (7 - (i & 7));
      byte = i / 8;
      bit = 1 << bitnum;
      a->as_u8[byte] |= bit;
    }
}

always_inline uword
ip6_address_is_zero (const ip6_address_t * a)
{
  int i;
  for (i = 0; i < ARRAY_LEN (a->as_uword); i++)
    if (a->as_uword[i] != 0)
      return 0;
  return 1;
}

/* Check for unspecified address ::0 */
always_inline uword
ip6_address_is_unspecified (const ip6_address_t * a)
{
  return ip6_address_is_zero (a);
}

/* Check for loopback address ::1 */
always_inline uword
ip6_address_is_loopback (const ip6_address_t * a)
{
  return (a->as_u64[0] == 0 &&
          a->as_u32[2] == 0 &&
          a->as_u16[6] == 0 && a->as_u8[14] == 0 && a->as_u8[15] == 1);
}

/* Check for link local unicast fe80::/10. */
always_inline uword
ip6_address_is_link_local_unicast (const ip6_address_t * a)
{
  return a->as_u8[0] == 0xfe && (a->as_u8[1] & 0xc0) == 0x80;
}

/* Check for unique local unicast fc00::/7. */
always_inline uword
ip6_address_is_local_unicast (const ip6_address_t * a)
{
  return (a->as_u8[0] & 0xfe) == 0xfc;
}

/* Check for unique global unicast 2000::/3. */
always_inline uword
ip6_address_is_global_unicast (const ip6_address_t * a)
{
  return (a->as_u8[0] & 0xe0) == 0x20;
}

/* Check for solicited node multicast 0xff02::1:ff00:0/104 */
always_inline uword
ip6_is_solicited_node_multicast_address (const ip6_address_t * a)
{
  return (a->as_u32[0] == clib_host_to_net_u32 (0xff020000)
          && a->as_u32[1] == 0
          && a->as_u32[2] == clib_host_to_net_u32 (1)
          && a->as_u8[12] == 0xff);
}

always_inline u32
ip6_address_hash_to_u32 (const ip6_address_t * a)
{
  return (a->as_u32[0] ^ a->as_u32[1] ^ a->as_u32[2] ^ a->as_u32[3]);
}

always_inline u64
ip6_address_hash_to_u64 (const ip6_address_t * a)
{
  return (a->as_u64[0] ^ a->as_u64[1]);
}

typedef struct
{
  /* 4 bit version, 8 bit traffic class and 20 bit flow label. */
  u32 ip_version_traffic_class_and_flow_label;

  /* Total packet length not including this header (but including
     any extension headers if present). */
  u16 payload_length;

  /* Protocol for next header. */
  u8 protocol;

  /* Hop limit decremented by router at each hop. */
  u8 hop_limit;

  /* Source and destination address. */
  ip6_address_t src_address, dst_address;
} ip6_header_t;

#define IP6_PACKET_TC_MASK 0x0FF00000
#define IP6_PACKET_DSCP_MASK 0x0FC00000
#define IP6_PACKET_ECN_MASK 0x00300000

always_inline ip_dscp_t
ip6_traffic_class (const ip6_header_t * i)
{
  return (i->ip_version_traffic_class_and_flow_label & IP6_PACKET_TC_MASK) >>
    20;
}

static_always_inline ip_dscp_t
ip6_traffic_class_network_order (const ip6_header_t * ip6)
{
  return (clib_net_to_host_u32 (ip6->ip_version_traffic_class_and_flow_label)
          & IP6_PACKET_TC_MASK) >> 20;
}

static_always_inline ip_dscp_t
ip6_dscp_network_order (const ip6_header_t * ip6)
{
  return (clib_net_to_host_u32 (ip6->ip_version_traffic_class_and_flow_label)
          & IP6_PACKET_DSCP_MASK) >> 22;
}

static_always_inline ip_ecn_t
ip6_ecn_network_order (const ip6_header_t * ip6)
{
  return (clib_net_to_host_u32 (ip6->ip_version_traffic_class_and_flow_label)
          & IP6_PACKET_ECN_MASK) >> 20;
}

static_always_inline void
ip6_set_traffic_class_network_order (ip6_header_t * ip6, ip_dscp_t dscp)
{
  u32 tmp =
    clib_net_to_host_u32 (ip6->ip_version_traffic_class_and_flow_label);
  tmp &= 0xf00fffff;
  tmp |= (dscp << 20);
  ip6->ip_version_traffic_class_and_flow_label = clib_host_to_net_u32 (tmp);
}

static_always_inline void
ip6_set_dscp_network_order (ip6_header_t * ip6, ip_dscp_t dscp)
{
  u32 tmp =
    clib_net_to_host_u32 (ip6->ip_version_traffic_class_and_flow_label);
  tmp &= 0xf03fffff;
  tmp |= (dscp << 22);
  ip6->ip_version_traffic_class_and_flow_label = clib_host_to_net_u32 (tmp);
}

static_always_inline void
ip6_set_ecn_network_order (ip6_header_t * ip6, ip_ecn_t ecn)
{
  u32 tmp =
    clib_net_to_host_u32 (ip6->ip_version_traffic_class_and_flow_label);
  tmp &= 0xffcfffff;
  tmp |= (ecn << 20);
  ip6->ip_version_traffic_class_and_flow_label = clib_host_to_net_u32 (tmp);
}

always_inline void *
ip6_next_header (ip6_header_t * i)
{
  return (void *) (i + 1);
}

always_inline void
ip6_copy_header (ip6_header_t * dst, const ip6_header_t * src)
{
  dst->ip_version_traffic_class_and_flow_label =
    src->ip_version_traffic_class_and_flow_label;
  dst->payload_length = src->payload_length;
  dst->protocol = src->protocol;
  dst->hop_limit = src->hop_limit;

  dst->src_address.as_uword[0] = src->src_address.as_uword[0];
  dst->src_address.as_uword[1] = src->src_address.as_uword[1];
  dst->dst_address.as_uword[0] = src->dst_address.as_uword[0];
  dst->dst_address.as_uword[1] = src->dst_address.as_uword[1];
}

always_inline void
ip6_tcp_reply_x1 (ip6_header_t * ip0, tcp_header_t * tcp0)
{
  {
    ip6_address_t src0, dst0;

    src0 = ip0->src_address;
    dst0 = ip0->dst_address;
    ip0->src_address = dst0;
    ip0->dst_address = src0;
  }

  {
    u16 src0, dst0;

    src0 = tcp0->src;
    dst0 = tcp0->dst;
    tcp0->src = dst0;
    tcp0->dst = src0;
  }
}

always_inline void
ip6_tcp_reply_x2 (ip6_header_t * ip0, ip6_header_t * ip1,
                  tcp_header_t * tcp0, tcp_header_t * tcp1)
{
  {
    ip6_address_t src0, dst0, src1, dst1;

    src0 = ip0->src_address;
    src1 = ip1->src_address;
    dst0 = ip0->dst_address;
    dst1 = ip1->dst_address;
    ip0->src_address = dst0;
    ip1->src_address = dst1;
    ip0->dst_address = src0;
    ip1->dst_address = src1;
  }

  {
    u16 src0, dst0, src1, dst1;

    src0 = tcp0->src;
    src1 = tcp1->src;
    dst0 = tcp0->dst;
    dst1 = tcp1->dst;
    tcp0->src = dst0;
    tcp1->src = dst1;
    tcp0->dst = src0;
    tcp1->dst = src1;
  }
}


/* *INDENT-OFF* */
typedef CLIB_PACKED (struct {
  u8 data;
}) ip6_pad1_option_t;
/* *INDENT-ON* */

/* *INDENT-OFF* */
typedef CLIB_PACKED (struct {
  u8 type;
  u8 len;
  u8 data[0];
}) ip6_padN_option_t;
/* *INDENT-ON* */

/* *INDENT-OFF* */
typedef CLIB_PACKED (struct {
#define IP6_MLDP_ALERT_TYPE  0x5
  u8 type;
  u8 len;
  u16 value;
}) ip6_router_alert_option_t;
/* *INDENT-ON* */

/* *INDENT-OFF* */
typedef CLIB_PACKED (struct {
  u8 next_hdr;
  /* Length of this header plus option data in 8 byte units. */
  u8 n_data_u64s;
}) ip6_ext_header_t;
/* *INDENT-ON* */

#define foreach_ext_hdr_type \
  _(IP6_HOP_BY_HOP_OPTIONS) \
  _(IPV6_ROUTE) \
  _(IPV6_FRAGMENTATION) \
  _(IPSEC_ESP) \
  _(IPSEC_AH) \
  _(IP6_DESTINATION_OPTIONS) \
  _(MOBILITY) \
  _(HIP) \
  _(SHIM6)

always_inline u8
ip6_ext_hdr (u8 nexthdr)
{
#ifdef CLIB_HAVE_VEC128
  static const u8x16 ext_hdr_types = {
#define _(x) IP_PROTOCOL_##x,
    foreach_ext_hdr_type
#undef _
  };

  return !u8x16_is_all_zero (ext_hdr_types == u8x16_splat (nexthdr));
#else
  /*
   * find out if nexthdr is an extension header or a protocol
   */
  return 0
#define _(x) || (nexthdr == IP_PROTOCOL_##x)
    foreach_ext_hdr_type;
#undef _
#endif
}

#define ip6_ext_header_len(p)  ((((ip6_ext_header_t *)(p))->n_data_u64s+1) << 3)
#define ip6_ext_authhdr_len(p) ((((ip6_ext_header_t *)(p))->n_data_u64s+2) << 2)

always_inline void *
ip6_ext_next_header (ip6_ext_header_t * ext_hdr)
{
  return (void *) ((u8 *) ext_hdr + ip6_ext_header_len (ext_hdr));
}

always_inline int
vlib_object_within_buffer_data (vlib_main_t * vm, vlib_buffer_t * b,
                                void *obj, size_t len)
{
  u8 *o = obj;
  if (o < b->data ||
      o + len > b->data + vlib_buffer_get_default_data_size (vm))
    return 0;
  return 1;
}

/*
 * find ipv6 extension header within ipv6 header within buffer b
 *
 * @param vm
 * @param b buffer to limit search to
 * @param ip6_header ipv6 header
 * @param header_type extension header type to search for
 * @param[out] prev_ext_header address of header preceding found header
 */
always_inline void *
ip6_ext_header_find (vlib_main_t * vm, vlib_buffer_t * b,
                     ip6_header_t * ip6_header, u8 header_type,
                     ip6_ext_header_t ** prev_ext_header)
{
  ip6_ext_header_t *prev = NULL;
  ip6_ext_header_t *result = NULL;
  if ((ip6_header)->protocol == header_type)
    {
      result = (void *) (ip6_header + 1);
      if (!vlib_object_within_buffer_data (vm, b, result,
                                           ip6_ext_header_len (result)))
        {
          result = NULL;
        }
    }
  else
    {
      result = NULL;
      prev = (void *) (ip6_header + 1);
      while (ip6_ext_hdr (prev->next_hdr) && prev->next_hdr != header_type)
        {
          prev = ip6_ext_next_header (prev);
          if (!vlib_object_within_buffer_data (vm, b, prev,
                                               ip6_ext_header_len (prev)))
            {
              prev = NULL;
              break;
            }
        }
      if (prev && (prev->next_hdr == header_type))
        {
          result = ip6_ext_next_header (prev);
          if (!vlib_object_within_buffer_data (vm, b, result,
                                               ip6_ext_header_len (result)))
            {
              result = NULL;
            }
        }
    }
  if (prev_ext_header)
    {
      *prev_ext_header = prev;
    }
  return result;
}

/*
 * walk extension headers, looking for a specific extension header and last
 * extension header, calculating length of all extension headers
 *
 * @param vm
 * @param b buffer to limit search to
 * @param ip6_header ipv6 header
 * @param find_hdr extension header to look for (ignored if ext_hdr is NULL)
 * @param length[out] length of all extension headers
 * @param ext_hdr[out] extension header of type find_hdr (may be NULL)
 * @param last_ext_hdr[out] last extension header (may be NULL)
 *
 * @return 0 on success, -1 on failure (ext headers crossing buffer boundary)
 */
always_inline int
ip6_walk_ext_hdr (vlib_main_t * vm, vlib_buffer_t * b,
                  const ip6_header_t * ip6_header, u8 find_hdr, u32 * length,
                  ip6_ext_header_t ** ext_hdr,
                  ip6_ext_header_t ** last_ext_hdr)
{
  if (!ip6_ext_hdr (ip6_header->protocol))
    {
      *length = 0;
      *ext_hdr = NULL;
      *last_ext_hdr = NULL;
      return 0;
    }
  *length = 0;
  ip6_ext_header_t *h = (void *) (ip6_header + 1);
  if (!vlib_object_within_buffer_data (vm, b, h, ip6_ext_header_len (h)))
    {
      return -1;
    }
  *length += ip6_ext_header_len (h);
  *last_ext_hdr = h;
  *ext_hdr = NULL;
  if (ip6_header->protocol == find_hdr)
    {
      *ext_hdr = h;
    }
  while (ip6_ext_hdr (h->next_hdr))
    {
      if (h->next_hdr == find_hdr)
        {
          h = ip6_ext_next_header (h);
          *ext_hdr = h;
        }
      else
        {
          h = ip6_ext_next_header (h);
        }
      if (!vlib_object_within_buffer_data (vm, b, h, ip6_ext_header_len (h)))
        {
          return -1;
        }
      *length += ip6_ext_header_len (h);
      *last_ext_hdr = h;
    }
  return 0;
}

/* *INDENT-OFF* */
typedef CLIB_PACKED (struct {
  u8 next_hdr;
  /* Length of this header plus option data in 8 byte units. */
  u8 n_data_u64s;
  u8 data[0];
}) ip6_hop_by_hop_ext_t;
/* *INDENT-ON* */

/* *INDENT-OFF* */
typedef CLIB_PACKED (struct {
  u8 next_hdr;
  u8 rsv;
  u16 fragment_offset_and_more;
  u32 identification;
}) ip6_frag_hdr_t;
/* *INDENT-ON* */

#define ip6_frag_hdr_offset(hdr) \
  (clib_net_to_host_u16((hdr)->fragment_offset_and_more) >> 3)

#define ip6_frag_hdr_offset_bytes(hdr) \
  (8 * ip6_frag_hdr_offset(hdr))

#define ip6_frag_hdr_more(hdr) \
  (clib_net_to_host_u16((hdr)->fragment_offset_and_more) & 0x1)

#define ip6_frag_hdr_offset_and_more(offset, more) \
  clib_host_to_net_u16(((offset) << 3) + !!(more))

#endif /* included_ip6_packet_h */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */