text: /*
   * gre.c: gre
   *
   * Copyright (c) 2012 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.
   */
  
  #include <vnet/vnet.h>
  #include <vnet/gre/gre.h>
  #include <vnet/adj/adj_midchain.h>
  
  gre_main_t gre_main;
  
  typedef struct
  {
    union
    {
      ip4_and_gre_header_t ip4_and_gre;
      u64 as_u64[3];
    };
  } ip4_and_gre_union_t;
  
  typedef struct
  {
    union
    {
      ip6_and_gre_header_t ip6_and_gre;
      u64 as_u64[3];
    };
  } ip6_and_gre_union_t;
  
  
  /* Packet trace structure */
  typedef struct
  {
    /* Tunnel-id / index in tunnel vector */
    u32 tunnel_id;
  
    /* pkt length */
    u32 length;
  
    /* tunnel ip addresses */
    ip46_address_t src;
    ip46_address_t dst;
  } gre_tx_trace_t;
  
  u8 *
  format_gre_tx_trace (u8 * s, va_list * args)
  {
    CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
    CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
    gre_tx_trace_t *t = va_arg (*args, gre_tx_trace_t *);
  
    s = format (s, "GRE: tunnel %d len %d src %U dst %U",
  	      t->tunnel_id, t->length,
  	      format_ip46_address, &t->src, IP46_TYPE_ANY,
  	      format_ip46_address, &t->dst, IP46_TYPE_ANY);
    return s;
  }
  
  u8 *
  format_gre_protocol (u8 * s, va_list * args)
  {
    gre_protocol_t p = va_arg (*args, u32);
    gre_main_t *gm = &gre_main;
    gre_protocol_info_t *pi = gre_get_protocol_info (gm, p);
  
    if (pi)
      s = format (s, "%s", pi->name);
    else
      s = format (s, "0x%04x", p);
  
    return s;
  }
  
  u8 *
  format_gre_header_with_length (u8 * s, va_list * args)
  {
    gre_main_t *gm = &gre_main;
    gre_header_t *h = va_arg (*args, gre_header_t *);
    u32 max_header_bytes = va_arg (*args, u32);
    gre_protocol_t p = clib_net_to_host_u16 (h->protocol);
    u32 indent, header_bytes;
  
    header_bytes = sizeof (h[0]);
    if (max_header_bytes != 0 && header_bytes > max_header_bytes)
      return format (s, "gre header truncated");
  
    indent = format_get_indent (s);
  
    s = format (s, "GRE %U", format_gre_protocol, p);
  
    if (max_header_bytes != 0 && header_bytes < max_header_bytes)
      {
        gre_protocol_info_t *pi = gre_get_protocol_info (gm, p);
        vlib_node_t *node = vlib_get_node (gm->vlib_main, pi->node_index);
        if (node->format_buffer)
  	s = format (s, "\n%U%U",
  		    format_white_space, indent,
  		    node->format_buffer, (void *) (h + 1),
  		    max_header_bytes - header_bytes);
      }
  
    return s;
  }
  
  u8 *
  format_gre_header (u8 * s, va_list * args)
  {
    gre_header_t *h = va_arg (*args, gre_header_t *);
    return format (s, "%U", format_gre_header_with_length, h, 0);
  }
  
  /* Returns gre protocol as an int in host byte order. */
  uword
  unformat_gre_protocol_host_byte_order (unformat_input_t * input,
  				       va_list * args)
  {
    u16 *result = va_arg (*args, u16 *);
    gre_main_t *gm = &gre_main;
    int i;
  
    /* Named type. */
    if (unformat_user (input, unformat_vlib_number_by_name,
  		     gm->protocol_info_by_name, &i))
      {
        gre_protocol_info_t *pi = vec_elt_at_index (gm->protocol_infos, i);
        *result = pi->protocol;
        return 1;
      }
  
    return 0;
  }
  
  uword
  unformat_gre_protocol_net_byte_order (unformat_input_t * input,
  				      va_list * args)
  {
    u16 *result = va_arg (*args, u16 *);
    if (!unformat_user (input, unformat_gre_protocol_host_byte_order, result))
      return 0;
    *result = clib_host_to_net_u16 ((u16) * result);
    return 1;
  }
  
  uword
  unformat_gre_header (unformat_input_t * input, va_list * args)
  {
    u8 **result = va_arg (*args, u8 **);
    gre_header_t _h, *h = &_h;
    u16 p;
  
    if (!unformat (input, "%U", unformat_gre_protocol_host_byte_order, &p))
      return 0;
  
    h->protocol = clib_host_to_net_u16 (p);
  
    /* Add header to result. */
    {
      void *p;
      u32 n_bytes = sizeof (h[0]);
  
      vec_add2 (*result, p, n_bytes);
      clib_memcpy (p, h, n_bytes);
    }
  
    return 1;
  }
  
  static int
  gre_proto_from_vnet_link (vnet_link_t link)
  {
    switch (link)
      {
      case VNET_LINK_IP4:
        return (GRE_PROTOCOL_ip4);
      case VNET_LINK_IP6:
        return (GRE_PROTOCOL_ip6);
      case VNET_LINK_MPLS:
        return (GRE_PROTOCOL_mpls_unicast);
      case VNET_LINK_ETHERNET:
        return (GRE_PROTOCOL_teb);
      case VNET_LINK_ARP:
        return (GRE_PROTOCOL_arp);
      case VNET_LINK_NSH:
        ASSERT (0);
        break;
      }
    ASSERT (0);
    return (GRE_PROTOCOL_ip4);
  }
  
  static u8 *
  gre_build_rewrite (vnet_main_t * vnm,
  		   u32 sw_if_index,
  		   vnet_link_t link_type, const void *dst_address)
  {
    gre_main_t *gm = &gre_main;
    ip4_and_gre_header_t *h4;
    ip6_and_gre_header_t *h6;
    gre_header_t *gre;
    u8 *rewrite = NULL;
    gre_tunnel_t *t;
    u32 ti;
    u8 is_ipv6;
  
    ti = gm->tunnel_index_by_sw_if_index[sw_if_index];
  
    if (~0 == ti)
      /* not one of ours */
      return (0);
  
    t = pool_elt_at_index (gm->tunnels, ti);
  
    is_ipv6 = t->tunnel_dst.fp_proto == FIB_PROTOCOL_IP6 ? 1 : 0;
  
    if (!is_ipv6)
      {
        vec_validate (rewrite, sizeof (*h4) - 1);
        h4 = (ip4_and_gre_header_t *) rewrite;
        gre = &h4->gre;
        h4->ip4.ip_version_and_header_length = 0x45;
        h4->ip4.ttl = 254;
        h4->ip4.protocol = IP_PROTOCOL_GRE;
        /* fixup ip4 header length and checksum after-the-fact */
        h4->ip4.src_address.as_u32 = t->tunnel_src.ip4.as_u32;
        h4->ip4.dst_address.as_u32 = t->tunnel_dst.fp_addr.ip4.as_u32;
        h4->ip4.checksum = ip4_header_checksum (&h4->ip4);
      }
    else
      {
        vec_validate (rewrite, sizeof (*h6) - 1);
        h6 = (ip6_and_gre_header_t *) rewrite;
        gre = &h6->gre;
        h6->ip6.ip_version_traffic_class_and_flow_label =
  	clib_host_to_net_u32 (6 << 28);
        h6->ip6.hop_limit = 255;
        h6->ip6.protocol = IP_PROTOCOL_GRE;
        /* fixup ip6 header length and checksum after-the-fact */
        h6->ip6.src_address.as_u64[0] = t->tunnel_src.ip6.as_u64[0];
        h6->ip6.src_address.as_u64[1] = t->tunnel_src.ip6.as_u64[1];
        h6->ip6.dst_address.as_u64[0] = t->tunnel_dst.fp_addr.ip6.as_u64[0];
        h6->ip6.dst_address.as_u64[1] = t->tunnel_dst.fp_addr.ip6.as_u64[1];
      }
  
    if (PREDICT_FALSE (t->type == GRE_TUNNEL_TYPE_ERSPAN))
      {
        gre->protocol = clib_host_to_net_u16 (GRE_PROTOCOL_erspan);
        gre->flags_and_version = clib_host_to_net_u16 (GRE_FLAGS_SEQUENCE);
      }
    else
      gre->protocol =
        clib_host_to_net_u16 (gre_proto_from_vnet_link (link_type));
  
    return (rewrite);
  }
  
  #define is_v4_packet(_h) ((*(u8*) _h) & 0xF0) == 0x40
  
  static void
  gre4_fixup (vlib_main_t * vm,
  	    ip_adjacency_t * adj, vlib_buffer_t * b0, const void *data)
  {
    ip4_header_t *ip0;
  
    ip0 = vlib_buffer_get_current (b0);
  
    /* Fixup the checksum and len fields in the GRE tunnel encap
     * that was applied at the midchain node */
    ip0->length = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0));
    ip0->checksum = ip4_header_checksum (ip0);
  }
  
  static void
  gre6_fixup (vlib_main_t * vm,
  	    ip_adjacency_t * adj, vlib_buffer_t * b0, const void *data)
  {
    ip6_header_t *ip0;
  
    ip0 = vlib_buffer_get_current (b0);
  
    /* Fixup the payload length field in the GRE tunnel encap that was applied
     * at the midchain node */
    ip0->payload_length =
      clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, b0) -
  			  sizeof (*ip0));
  }
  
  void
  gre_update_adj (vnet_main_t * vnm, u32 sw_if_index, adj_index_t ai)
  {
    gre_main_t *gm = &gre_main;
    gre_tunnel_t *t;
    u32 ti;
    u8 is_ipv6;
  
    ti = gm->tunnel_index_by_sw_if_index[sw_if_index];
    t = pool_elt_at_index (gm->tunnels, ti);
    is_ipv6 = t->tunnel_dst.fp_proto == FIB_PROTOCOL_IP6 ? 1 : 0;
  
    adj_nbr_midchain_update_rewrite
      (ai, !is_ipv6 ? gre4_fixup : gre6_fixup, NULL,
       (VNET_LINK_ETHERNET == adj_get_link_type (ai) ?
        ADJ_FLAG_MIDCHAIN_NO_COUNT : ADJ_FLAG_NONE),
       gre_build_rewrite (vnm, sw_if_index, adj_get_link_type (ai), NULL));
  
    gre_tunnel_stack (ai);
  }
  
  
  typedef enum
  {
    GRE_ENCAP_NEXT_L2_MIDCHAIN,
    GRE_ENCAP_N_NEXT,
  } gre_encap_next_t;
  
  /**
   * @brief TX function. Only called for L2 payload including TEB or ERSPAN.
   *        L3 traffic uses the adj-midchains.
   */
  static uword
  gre_interface_tx (vlib_main_t * vm,
  		  vlib_node_runtime_t * node, vlib_frame_t * frame)
  {
    gre_main_t *gm = &gre_main;
    vnet_main_t *vnm = gm->vnet_main;
    u32 next_index;
    u32 *from, *to_next, n_left_from, n_left_to_next;
    u32 sw_if_index0 = 0;
    u32 sw_if_index1 = 0;
    adj_index_t adj_index0 = ADJ_INDEX_INVALID;
    adj_index_t adj_index1 = ADJ_INDEX_INVALID;
    gre_tunnel_t *gt0 = NULL;
    gre_tunnel_t *gt1 = NULL;
  
    /* Vector of buffer / pkt indices we're supposed to process */
    from = vlib_frame_vector_args (frame);
  
    /* Number of buffers / pkts */
    n_left_from = frame->n_vectors;
  
    /* Speculatively send the first buffer to the last disposition we used */
    next_index = GRE_ENCAP_NEXT_L2_MIDCHAIN;
  
    while (n_left_from > 0)
      {
        /* set up to enqueue to our disposition with index = next_index */
        vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
  
        while (n_left_from >= 4 && n_left_to_next >= 2)
  	{
  	  u32 bi0 = from[0];
  	  u32 bi1 = from[1];
  	  vlib_buffer_t *b0 = vlib_get_buffer (vm, bi0);
  	  vlib_buffer_t *b1 = vlib_get_buffer (vm, bi1);
  
  	  to_next[0] = bi0;
  	  to_next[1] = bi1;
  	  from += 2;
  	  to_next += 2;
  	  n_left_to_next -= 2;
  	  n_left_from -= 2;
  
  	  if (sw_if_index0 != vnet_buffer (b0)->sw_if_index[VLIB_TX])
  	    {
  	      sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_TX];
  	      vnet_hw_interface_t *hi0 =
  		vnet_get_sup_hw_interface (vnm, sw_if_index0);
  	      gt0 = &gm->tunnels[hi0->dev_instance];
  	      adj_index0 = gt0->l2_adj_index;
  	    }
  
  	  if (sw_if_index1 != vnet_buffer (b1)->sw_if_index[VLIB_TX])
  	    {
  	      if (sw_if_index0 == vnet_buffer (b1)->sw_if_index[VLIB_TX])
  		{
  		  sw_if_index1 = sw_if_index0;
  		  gt1 = gt0;
  		  adj_index1 = adj_index0;
  		}
  	      else
  		{
  		  sw_if_index1 = vnet_buffer (b1)->sw_if_index[VLIB_TX];
  		  vnet_hw_interface_t *hi1 =
  		    vnet_get_sup_hw_interface (vnm, sw_if_index1);
  		  gt1 = &gm->tunnels[hi1->dev_instance];
  		  adj_index1 = gt1->l2_adj_index;
  		}
  	    }
  
  	  vnet_buffer (b0)->ip.adj_index[VLIB_TX] = adj_index0;
  	  vnet_buffer (b1)->ip.adj_index[VLIB_TX] = adj_index1;
  
  	  if (PREDICT_FALSE (gt0->type == GRE_TUNNEL_TYPE_ERSPAN))
  	    {
  	      /* Encap GRE seq# and ERSPAN type II header */
  	      vlib_buffer_advance (b0, -sizeof (erspan_t2_t));
  	      erspan_t2_t *h0 = vlib_buffer_get_current (b0);
  	      u32 seq_num = clib_atomic_fetch_add (&gt0->gre_sn->seq_num, 1);
  	      u64 hdr = clib_host_to_net_u64 (ERSPAN_HDR2);
  	      h0->seq_num = clib_host_to_net_u32 (seq_num);
  	      h0->t2_u64 = hdr;
  	      h0->t2.cos_en_t_session |=
  		clib_host_to_net_u16 (gt0->session_id);
  	    }
  	  if (PREDICT_FALSE (gt1->type == GRE_TUNNEL_TYPE_ERSPAN))
  	    {
  	      /* Encap GRE seq# and ERSPAN type II header */
  	      vlib_buffer_advance (b1, -sizeof (erspan_t2_t));
  	      erspan_t2_t *h1 = vlib_buffer_get_current (b1);
  	      u32 seq_num = clib_atomic_fetch_add (&gt1->gre_sn->seq_num, 1);
  	      u64 hdr = clib_host_to_net_u64 (ERSPAN_HDR2);
  	      h1->seq_num = clib_host_to_net_u32 (seq_num);
  	      h1->t2_u64 = hdr;
  	      h1->t2.cos_en_t_session |=
  		clib_host_to_net_u16 (gt1->session_id);
  	    }
  
  	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
  	    {
  	      gre_tx_trace_t *tr0 = vlib_add_trace (vm, node,
  						    b0, sizeof (*tr0));
  	      tr0->tunnel_id = gt0 - gm->tunnels;
  	      tr0->src = gt0->tunnel_src;
  	      tr0->dst = gt0->tunnel_dst.fp_addr;
  	      tr0->length = vlib_buffer_length_in_chain (vm, b0);
  	    }
  	  if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
  	    {
  	      gre_tx_trace_t *tr1 = vlib_add_trace (vm, node,
  						    b1, sizeof (*tr1));
  	      tr1->tunnel_id = gt1 - gm->tunnels;
  	      tr1->src = gt1->tunnel_src;
  	      tr1->dst = gt1->tunnel_dst.fp_addr;
  	      tr1->length = vlib_buffer_length_in_chain (vm, b1);
  	    }
  	}
  
        while (n_left_from > 0 && n_left_to_next > 0)
  	{
  	  u32 bi0 = from[0];
  	  vlib_buffer_t *b0 = vlib_get_buffer (vm, bi0);
  
  	  to_next[0] = bi0;
  	  from += 1;
  	  to_next += 1;
  	  n_left_from -= 1;
  	  n_left_to_next -= 1;
  
  	  if (sw_if_index0 != vnet_buffer (b0)->sw_if_index[VLIB_TX])
  	    {
  	      sw_if_index0 = vnet_buffer (b0)->sw_if_index[VLIB_TX];
  	      vnet_hw_interface_t *hi0 =
  		vnet_get_sup_hw_interface (vnm, sw_if_index0);
  	      gt0 = &gm->tunnels[hi0->dev_instance];
  	      adj_index0 = gt0->l2_adj_index;
  	    }
  
  	  vnet_buffer (b0)->ip.adj_index[VLIB_TX] = adj_index0;
  
  	  if (PREDICT_FALSE (gt0->type == GRE_TUNNEL_TYPE_ERSPAN))
  	    {
  	      /* Encap GRE seq# and ERSPAN type II header */
  	      vlib_buffer_advance (b0, -sizeof (erspan_t2_t));
  	      erspan_t2_t *h0 = vlib_buffer_get_current (b0);
  	      u32 seq_num = clib_atomic_fetch_add (&gt0->gre_sn->seq_num, 1);
  	      u64 hdr = clib_host_to_net_u64 (ERSPAN_HDR2);
  	      h0->seq_num = clib_host_to_net_u32 (seq_num);
  	      h0->t2_u64 = hdr;
  	      h0->t2.cos_en_t_session |=
  		clib_host_to_net_u16 (gt0->session_id);
  	    }
  
  	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
  	    {
  	      gre_tx_trace_t *tr = vlib_add_trace (vm, node,
  						   b0, sizeof (*tr));
  	      tr->tunnel_id = gt0 - gm->tunnels;
  	      tr->src = gt0->tunnel_src;
  	      tr->dst = gt0->tunnel_dst.fp_addr;
  	      tr->length = vlib_buffer_length_in_chain (vm, b0);
  	    }
  	}
  
        vlib_put_next_frame (vm, node, next_index, n_left_to_next);
      }
  
    vlib_node_increment_counter (vm, node->node_index,
  			       GRE_ERROR_PKTS_ENCAP, frame->n_vectors);
  
    return frame->n_vectors;
  }
  
  static char *gre_error_strings[] = {
  #define gre_error(n,s) s,
  #include "error.def"
  #undef gre_error
  };
  
  /* *INDENT-OFF* */
  VLIB_REGISTER_NODE (gre_encap_node) =
  {
    .function = gre_interface_tx,
    .name = "gre-encap",
    .vector_size = sizeof (u32),
    .format_trace = format_gre_tx_trace,
    .type = VLIB_NODE_TYPE_INTERNAL,
    .n_errors = GRE_N_ERROR,
    .error_strings = gre_error_strings,
    .n_next_nodes = GRE_ENCAP_N_NEXT,
    .next_nodes = {
      [GRE_ENCAP_NEXT_L2_MIDCHAIN] = "adj-l2-midchain",
    },
  };
  
  VLIB_NODE_FUNCTION_MULTIARCH (gre_encap_node, gre_interface_tx)
  /* *INDENT-ON* */
  
  static u8 *
  format_gre_tunnel_name (u8 * s, va_list * args)
  {
    u32 dev_instance = va_arg (*args, u32);
    gre_main_t *gm = &gre_main;
    gre_tunnel_t *t;
  
    if (dev_instance >= vec_len (gm->tunnels))
      return format (s, "<improperly-referenced>");
  
    t = pool_elt_at_index (gm->tunnels, dev_instance);
    return format (s, "gre%d", t->user_instance);
  }
  
  static u8 *
  format_gre_device (u8 * s, va_list * args)
  {
    u32 dev_instance = va_arg (*args, u32);
    CLIB_UNUSED (int verbose) = va_arg (*args, int);
  
    s = format (s, "GRE tunnel: id %d\n", dev_instance);
    return s;
  }
  
  /* *INDENT-OFF* */
  VNET_DEVICE_CLASS (gre_device_class) = {
    .name = "GRE tunnel device",
    .format_device_name = format_gre_tunnel_name,
    .format_device = format_gre_device,
    .format_tx_trace = format_gre_tx_trace,
    .admin_up_down_function = gre_interface_admin_up_down,
  #ifdef SOON
    .clear counter = 0;
  #endif
  };
  
  VNET_HW_INTERFACE_CLASS (gre_hw_interface_class) = {
    .name = "GRE",
    .format_header = format_gre_header_with_length,
    .unformat_header = unformat_gre_header,
    .build_rewrite = gre_build_rewrite,
    .update_adjacency = gre_update_adj,
    .flags = VNET_HW_INTERFACE_CLASS_FLAG_P2P,
  };
  /* *INDENT-ON* */
  
  static void
  add_protocol (gre_main_t * gm, gre_protocol_t protocol, char *protocol_name)
  {
    gre_protocol_info_t *pi;
    u32 i;
  
    vec_add2 (gm->protocol_infos, pi, 1);
    i = pi - gm->protocol_infos;
  
    pi->name = protocol_name;
    pi->protocol = protocol;
    pi->next_index = pi->node_index = ~0;
  
    hash_set (gm->protocol_info_by_protocol, protocol, i);
    hash_set_mem (gm->protocol_info_by_name, pi->name, i);
  }
  
  static clib_error_t *
  gre_init (vlib_main_t * vm)
  {
    gre_main_t *gm = &gre_main;
    clib_error_t *error;
    ip_main_t *im = &ip_main;
    ip_protocol_info_t *pi;
  
    clib_memset (gm, 0, sizeof (gm[0]));
    gm->vlib_main = vm;
    gm->vnet_main = vnet_get_main ();
  
    if ((error = vlib_call_init_function (vm, ip_main_init)))
      return error;
  
    if ((error = vlib_call_init_function (vm, ip4_lookup_init)))
      return error;
  
    if ((error = vlib_call_init_function (vm, ip6_lookup_init)))
      return error;
  
    /* Set up the ip packet generator */
    pi = ip_get_protocol_info (im, IP_PROTOCOL_GRE);
    pi->format_header = format_gre_header;
    pi->unformat_pg_edit = unformat_pg_gre_header;
  
    gm->protocol_info_by_name = hash_create_string (0, sizeof (uword));
    gm->protocol_info_by_protocol = hash_create (0, sizeof (uword));
    gm->tunnel_by_key4 =
      hash_create_mem (0, sizeof (gre_tunnel_key4_t), sizeof (uword));
    gm->tunnel_by_key6 =
      hash_create_mem (0, sizeof (gre_tunnel_key6_t), sizeof (uword));
    gm->seq_num_by_key =
      hash_create_mem (0, sizeof (gre_sn_key_t), sizeof (uword));
  
  #define _(n,s) add_protocol (gm, GRE_PROTOCOL_##s, #s);
    foreach_gre_protocol
  #undef _
      return vlib_call_init_function (vm, gre_input_init);
  }
  
  VLIB_INIT_FUNCTION (gre_init);
  
  /*
   * fd.io coding-style-patch-verification: ON
   *
   * Local Variables:
   * eval: (c-set-style "gnu")
   * End:
   */
  