src/vnet/ip/ip6_packet.h

/*
 * 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>
#include <stdbool.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 */
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;

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
#define IP6_PACKET_FL_MASK   0x000FFFFF

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 |= ((0x3 & ecn) << 20);
  ip6->ip_version_traffic_class_and_flow_label = clib_host_to_net_u32 (tmp);
}

static_always_inline u32
ip6_flow_label_network_order (const ip6_header_t *ip6)
{
  u32 tmp =
    clib_net_to_host_u32 (ip6->ip_version_traffic_class_and_flow_label);
  return (tmp & 0xfffff);
}

static_always_inline void
ip6_set_flow_label_network_order (ip6_header_t *ip6, u32 flow_label)
{
  u32 tmp =
    clib_net_to_host_u32 (ip6->ip_version_traffic_class_and_flow_label);
  tmp &= 0xfff00000;
  tmp |= flow_label & 0x000fffff;
  ip6->ip_version_traffic_class_and_flow_label = clib_host_to_net_u32 (tmp);
}

static_always_inline u32
ip6_hop_limit_network_order (const ip6_header_t *ip6)
{
  return (ip6->hop_limit);
}

static_always_inline void
ip6_set_hop_limit_network_order (ip6_header_t *ip6, u8 hop_limit)
{
  ip6->hop_limit = hop_limit;
}

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;
  }
}

typedef CLIB_PACKED (struct {
  u8 data;
}) ip6_pad1_option_t;

typedef CLIB_PACKED (struct {
  u8 type;
  u8 len;
  u8 data[0];
}) ip6_padN_option_t;

typedef CLIB_PACKED (struct {
#define IP6_MLDP_ALERT_TYPE  0x5
  u8 type;
  u8 len;
  u16 value;
}) ip6_router_alert_option_t;

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;

#define foreach_ext_hdr_type \
  _(IP6_HOP_BY_HOP_OPTIONS) \
  _(IPV6_ROUTE) \
  _(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
}

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;

typedef CLIB_PACKED (struct {
  u8 next_hdr;
  u8 rsv;
  u16 fragment_offset_and_more;
  u32 identification;
}) ip6_frag_hdr_t;

#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))

#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)

static inline int
ip6_ext_header_len_s (ip_protocol_t nh, void *p)
{
  if (ip6_ext_hdr (nh))
    return ip6_ext_header_len (p);
  switch (nh)
    {
    case IP_PROTOCOL_IPSEC_AH:
      return ip6_ext_authhdr_len (p);
    case IP_PROTOCOL_IPV6_FRAGMENTATION:
      return sizeof (ip6_frag_hdr_t);
    case IP_PROTOCOL_ICMP6:
      return 4;
    case IP_PROTOCOL_UDP:
      return 8;
    case IP_PROTOCOL_TCP:
      return 20;
    default: /* Caller is responsible for validating the length of terminating
	     protocols */
	     ;
    }
  return 0;
}

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 void *
ip6_ext_next_header_offset (void *hdr, u16 offset)
{
  return (hdr + offset);
}

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;
}

/* Returns the number of bytes left in buffer from p. */
static inline u32
vlib_bytes_left_in_buffer (vlib_buffer_t *b, void *obj)
{
  return b->current_length - (((u8 *) obj - b->data) - b->current_data);
}

always_inline void *
ip6_ext_next_header_s (ip_protocol_t cur_nh, void *hdr, u32 max_offset,
		       u32 *offset, int *res_nh, bool *last)
{
  u16 hdrlen = 0;
  int new_nh = -1;
  void *res = 0;
  if (ip6_ext_hdr (cur_nh))
    {
      hdrlen = ip6_ext_header_len (hdr);
      new_nh = ((ip6_ext_header_t *) hdr)->next_hdr;
      res = hdr + hdrlen;
    }
  else if (cur_nh == IP_PROTOCOL_IPV6_FRAGMENTATION)
    {
      ip6_frag_hdr_t *frag_hdr = (ip6_frag_hdr_t *) hdr;
      if (ip6_frag_hdr_offset (frag_hdr) > 0)
	*last = true;
      new_nh = frag_hdr->next_hdr;
      hdrlen = sizeof (ip6_frag_hdr_t);
      res = hdr + hdrlen;
    }
  else if (cur_nh == IP_PROTOCOL_IPSEC_AH)
    {
      new_nh = ((ip6_ext_header_t *) hdr)->next_hdr;
      hdrlen = ip6_ext_authhdr_len (hdr);
      res = hdr + hdrlen;
    }
  else
    {
      ;
    }

  if (res && (*offset + hdrlen) >= max_offset)
    {
      return 0;
    }
  *res_nh = new_nh;
  *offset += hdrlen;
  return res;
}

#define IP6_EXT_HDR_MAX	      (4)   /* Maximum number of headers */
#define IP6_EXT_HDR_MAX_DEPTH (256) /* Maximum header depth */
typedef struct
{
  int length;
  struct
  {
    u16 protocol;
    u16 offset;
  } eh[IP6_EXT_HDR_MAX];
} ip6_ext_hdr_chain_t;

/*
 * Find ipv6 extension header within ipv6 header within
 * whichever is smallest of buffer or IP6_EXT_HDR_MAX_DEPTH.
 * The complete header chain must be in first buffer.
 *
 * The complete header chain (up to the terminating header) is
 * returned in res.
 * Returns the index of the find_hdr_type if > 0. Otherwise
 * it returns the index of the last header.
 */
always_inline int
ip6_ext_header_walk (vlib_buffer_t *b, ip6_header_t *ip, int find_hdr_type,
		     ip6_ext_hdr_chain_t *res)
{
  int i = 0;
  int found = -1;
  void *next_header = ip6_next_header (ip);
  int next_proto = ip->protocol;
  res->length = 0;
  u32 n_bytes_this_buffer =
    clib_min (vlib_bytes_left_in_buffer (b, ip), IP6_EXT_HDR_MAX_DEPTH);
  u32 max_offset = clib_min (n_bytes_this_buffer,
			     sizeof (ip6_header_t) +
			       clib_net_to_host_u16 (ip->payload_length));
  u32 offset = sizeof (ip6_header_t);
  if ((ip6_ext_header_len_s (ip->protocol, next_header) + offset) > max_offset)
    {
      return -1;
    }
  bool last = false;
  while (next_header)
    {
      /* Move on to next header */
      res->eh[i].offset = offset;
      res->eh[i].protocol = next_proto;
      if (next_proto == find_hdr_type)
	found = i;
      i++;
      if (last)
	break;
      if (i > IP6_EXT_HDR_MAX)
	break;
      next_header = ip6_ext_next_header_s (next_proto, next_header, max_offset,
					   &offset, &next_proto, &last);
    }
  res->length = i;
  if (find_hdr_type < 0)
    return i - 1;
  return found != -1 ? found : i - 1;
}

always_inline void *
ip6_ext_header_find (vlib_main_t *vm, vlib_buffer_t *b, ip6_header_t *ip,
		     int find_hdr_type, ip6_ext_header_t **prev_ext_header)
{
  ip6_ext_hdr_chain_t hdr_chain;
  int res = ip6_ext_header_walk (b, ip, find_hdr_type, &hdr_chain);
  if (res < 0)
    return 0;

  if (prev_ext_header)
    {
      if (res > 0)
	{
	  *prev_ext_header =
	    ip6_ext_next_header_offset (ip, hdr_chain.eh[res - 1].offset);
	}
      else
	{
	  *prev_ext_header = 0;
	}
    }
  if (find_hdr_type == hdr_chain.eh[res].protocol)
    return ip6_ext_next_header_offset (ip, hdr_chain.eh[res].offset);
  return 0;
}

#endif /* included_ip6_packet_h */

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