text: 
  /*
   * 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.
   */
  #include <vppinfra/error.h>
  #include <vppinfra/hash.h>
  #include <vnet/vnet.h>
  #include <vnet/ip/ip.h>
  #include <vnet/ethernet/ethernet.h>
  #include <vnet/vxlan/vxlan.h>
  
  /* Statistics (not all errors) */
  #define foreach_vxlan_encap_error    \
  _(ENCAPSULATED, "good packets encapsulated")
  
  static char * vxlan_encap_error_strings[] = {
  #define _(sym,string) string,
    foreach_vxlan_encap_error
  #undef _
  };
  
  typedef enum {
  #define _(sym,str) VXLAN_ENCAP_ERROR_##sym,
      foreach_vxlan_encap_error
  #undef _
      VXLAN_ENCAP_N_ERROR,
  } vxlan_encap_error_t;
  
  typedef enum {
      VXLAN_ENCAP_NEXT_DROP,
      VXLAN_ENCAP_N_NEXT,
  } vxlan_encap_next_t;
  
  typedef struct {
    u32 tunnel_index;
    u32 vni;
  } vxlan_encap_trace_t;
  
  u8 * format_vxlan_encap_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 *);
    vxlan_encap_trace_t * t 
        = va_arg (*args, vxlan_encap_trace_t *);
  
    s = format (s, "VXLAN encap to vxlan_tunnel%d vni %d", 
  	      t->tunnel_index, t->vni);
    return s;
  }
  
  always_inline uword
  vxlan_encap_inline (vlib_main_t * vm,
  		    vlib_node_runtime_t * node,
  		    vlib_frame_t * from_frame,
  		    u8 is_ip4, u8 csum_offload)
  {
    u32 n_left_from, next_index, * from, * to_next;
    vxlan_main_t * vxm = &vxlan_main;
    vnet_main_t * vnm = vxm->vnet_main;
    vnet_interface_main_t * im = &vnm->interface_main;
    vlib_combined_counter_main_t * tx_counter = im->combined_sw_if_counters + VNET_INTERFACE_COUNTER_TX;
    u32 pkts_encapsulated = 0;
    u32 thread_index = vlib_get_thread_index();
    u32 stats_sw_if_index, stats_n_packets, stats_n_bytes;
    u32 sw_if_index0 = 0, sw_if_index1 = 0;
    u32 next0 = 0, next1 = 0;
    vnet_hw_interface_t * hi0, * hi1;
    vxlan_tunnel_t * t0 = NULL, * t1 = NULL;
  
    from = vlib_frame_vector_args (from_frame);
    n_left_from = from_frame->n_vectors;
  
    next_index = node->cached_next_index;
    stats_sw_if_index = node->runtime_data[0];
    stats_n_packets = stats_n_bytes = 0;
  
    STATIC_ASSERT_SIZEOF(ip6_vxlan_header_t, 56);
    STATIC_ASSERT_SIZEOF(ip4_vxlan_header_t, 36);
  
    word const underlay_hdr_len = is_ip4 ?
      sizeof(ip4_vxlan_header_t) : sizeof(ip6_vxlan_header_t);
    u16 const l3_len = is_ip4 ? sizeof(ip4_header_t) : sizeof(ip6_header_t);
    u32 const csum_flags = is_ip4 ?
      VNET_BUFFER_F_OFFLOAD_IP_CKSUM | VNET_BUFFER_F_IS_IP4 |
      VNET_BUFFER_F_OFFLOAD_UDP_CKSUM :
      VNET_BUFFER_F_OFFLOAD_UDP_CKSUM;
  
    while (n_left_from > 0)
      {
        u32 n_left_to_next;
  
        vlib_get_next_frame (vm, node, next_index,
  			   to_next, n_left_to_next);
  
        while (n_left_from >= 4 && n_left_to_next >= 2)
  	{
  	  /* Prefetch next iteration. */
  	  {
  	    vlib_buffer_t * p2, * p3;
  
  	    p2 = vlib_get_buffer (vm, from[2]);
  	    p3 = vlib_get_buffer (vm, from[3]);
  
  	    vlib_prefetch_buffer_header (p2, LOAD);
  	    vlib_prefetch_buffer_header (p3, LOAD);
  
  	    CLIB_PREFETCH (p2->data, 2*CLIB_CACHE_LINE_BYTES, LOAD);
  	    CLIB_PREFETCH (p3->data, 2*CLIB_CACHE_LINE_BYTES, LOAD);
  	  }
  
  	  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);
            u32 flow_hash0 = vnet_l2_compute_flow_hash (b0);
            u32 flow_hash1 = vnet_l2_compute_flow_hash (b1);
  
  	  to_next[0] = bi0;
  	  to_next[1] = bi1;
  	  from += 2;
  	  to_next += 2;
  	  n_left_to_next -= 2;
  	  n_left_from -= 2;
  
  	  /* Get next node index and adj index from tunnel next_dpo */
  	  if (sw_if_index0 != vnet_buffer(b0)->sw_if_index[VLIB_TX])
  	    {
  	      sw_if_index0 = vnet_buffer(b0)->sw_if_index[VLIB_TX];
  	      hi0 = vnet_get_sup_hw_interface (vnm, sw_if_index0);
  	      t0 = &vxm->tunnels[hi0->dev_instance];
  	      /* Note: change to always set next0 if it may be set to drop */
  	      next0 = t0->next_dpo.dpoi_next_node;
  	    }
            vnet_buffer(b0)->ip.adj_index[VLIB_TX] = t0->next_dpo.dpoi_index;
  
  	  /* Get next node index and adj index from tunnel next_dpo */
  	  if (sw_if_index1 != vnet_buffer(b1)->sw_if_index[VLIB_TX])
  	    {
  	      sw_if_index1 = vnet_buffer(b1)->sw_if_index[VLIB_TX];
  	      hi1 = vnet_get_sup_hw_interface (vnm, sw_if_index1); 
  	      t1 = &vxm->tunnels[hi1->dev_instance];
  	      /* Note: change to always set next1 if it may be set to drop */
  	      next1 = t1->next_dpo.dpoi_next_node;
  	    }
            vnet_buffer(b1)->ip.adj_index[VLIB_TX] = t1->next_dpo.dpoi_index;
  
            ASSERT(vec_len(t0->rewrite) == underlay_hdr_len);
            ASSERT(vec_len(t1->rewrite) == underlay_hdr_len);
  
            vlib_buffer_advance (b0, -underlay_hdr_len);
            vlib_buffer_advance (b1, -underlay_hdr_len);
  
   	  u32 len0 = vlib_buffer_length_in_chain (vm, b0);
   	  u32 len1 = vlib_buffer_length_in_chain (vm, b1);
            u16 payload_l0 = clib_host_to_net_u16 (len0 - l3_len);
            u16 payload_l1 = clib_host_to_net_u16 (len1 - l3_len);
  
            ip4_header_t * ip4_0, * ip4_1;
            ip6_header_t * ip6_0, * ip6_1;
            udp_header_t * udp0, * udp1;
            u8 * l3_0, * l3_1;
  	  if (is_ip4)
  	    {
                ip4_vxlan_header_t * hdr0 = vlib_buffer_get_current(b0);
                ip4_vxlan_header_t * rewrite0 = (void *)t0->rewrite;
                ip4_vxlan_header_t * hdr1 = vlib_buffer_get_current(b1);
                ip4_vxlan_header_t * rewrite1 = (void *)t1->rewrite;
                *hdr0 = *rewrite0;
                *hdr1 = *rewrite1;
  
  	      /* Fix the IP4 checksum and length */
  	      ip4_0 = &hdr0->ip4;
  	      ip4_1 = &hdr1->ip4;
                ip4_0->length = clib_host_to_net_u16 (len0);
                ip4_1->length = clib_host_to_net_u16 (len1);
  
                l3_0 = (u8 *)ip4_0;
                l3_1 = (u8 *)ip4_1;
  	      udp0 = &hdr0->udp;
  	      udp1 = &hdr1->udp;
  	    }
  	  else /* ipv6 */
  	    {
                ip6_vxlan_header_t * hdr0 = vlib_buffer_get_current(b0);
                ip6_vxlan_header_t * rewrite0 = (void *) t0->rewrite;
                ip6_vxlan_header_t * hdr1 = vlib_buffer_get_current(b0);
                ip6_vxlan_header_t * rewrite1 = (void *) t1->rewrite;
                *hdr0 = *rewrite0;
                *hdr1 = *rewrite1;
  
  	      /* Fix IP6 payload length */
                ip6_0 = &hdr0->ip6;
                ip6_1 = &hdr1->ip6;
  	      ip6_0->payload_length = payload_l0;
  	      ip6_1->payload_length = payload_l1;
  
                l3_0 = (u8 *)ip6_0;
                l3_1 = (u8 *)ip6_1;
                udp0 = &hdr0->udp;
                udp1 = &hdr1->udp;
  	    }
  
            /* Fix UDP length  and set source port */
            udp0->length = payload_l0;
            udp0->src_port = flow_hash0;
            udp1->length = payload_l1;
            udp1->src_port = flow_hash1;
  
            if (csum_offload)
              {
                b0->flags |= csum_flags;
                vnet_buffer (b0)->l3_hdr_offset = l3_0 - b0->data;
                vnet_buffer (b0)->l4_hdr_offset = (u8 *) udp0 - b0->data;
                b1->flags |= csum_flags;
                vnet_buffer (b1)->l3_hdr_offset = l3_1 - b1->data;
                vnet_buffer (b1)->l4_hdr_offset = (u8 *) udp1 - b1->data;
              }
            /* IPv4 UDP checksum only if checksum offload is used */
            else if (is_ip4)
              {
                ip_csum_t sum0 = ip4_0->checksum;
                sum0 = ip_csum_update (sum0, 0, ip4_0->length, ip4_header_t,
                    length /* changed member */);
                ip4_0->checksum = ip_csum_fold (sum0);
                ip_csum_t sum1 = ip4_1->checksum;
                sum1 = ip_csum_update (sum1, 0, ip4_1->length, ip4_header_t,
                    length /* changed member */);
                ip4_1->checksum = ip_csum_fold (sum1);
              }
            /* IPv6 UDP checksum is mandatory */
            else
              {
                int bogus = 0;
  
                udp0->checksum = ip6_tcp_udp_icmp_compute_checksum
                  (vm, b0, ip6_0, &bogus);
                ASSERT(bogus == 0);
                if (udp0->checksum == 0)
                  udp0->checksum = 0xffff;
                udp1->checksum = ip6_tcp_udp_icmp_compute_checksum
                  (vm, b1, ip6_1, &bogus);
                ASSERT(bogus == 0);
                if (udp1->checksum == 0)
                  udp1->checksum = 0xffff;
              }
  
  	  /* Batch stats increment on the same vxlan tunnel so counter is not
  	     incremented per packet. Note stats are still incremented for deleted
  	     and admin-down tunnel where packets are dropped. It is not worthwhile
  	     to check for this rare case and affect normal path performance. */
            if (sw_if_index0 == sw_if_index1)
              {
                if (PREDICT_FALSE(sw_if_index0 != stats_sw_if_index))
                  {
                    if (stats_n_packets) 
                      {
                        vlib_increment_combined_counter (tx_counter, thread_index,
                            stats_sw_if_index, stats_n_packets, stats_n_bytes);
                        stats_n_packets = stats_n_bytes = 0;
                      }
                    stats_sw_if_index = sw_if_index0;
                  }
                stats_n_packets += 2;
                stats_n_bytes += len0 + len1;
              }
            else
              {
                vlib_increment_combined_counter (tx_counter, thread_index,
                    sw_if_index0, 1, len0);
                vlib_increment_combined_counter (tx_counter, thread_index,
                    sw_if_index1, 1, len1);
              }
            pkts_encapsulated += 2;
  
  	  if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED)) 
              {
                vxlan_encap_trace_t *tr = 
                  vlib_add_trace (vm, node, b0, sizeof (*tr));
                tr->tunnel_index = t0 - vxm->tunnels;
                tr->vni = t0->vni;
             }
  
            if (PREDICT_FALSE(b1->flags & VLIB_BUFFER_IS_TRACED)) 
              {
                vxlan_encap_trace_t *tr = 
                  vlib_add_trace (vm, node, b1, sizeof (*tr));
                tr->tunnel_index = t1 - vxm->tunnels;
                tr->vni = t1->vni;
              }
  
  	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
  					   to_next, n_left_to_next,
  					   bi0, bi1, next0, next1);
  	}
  
        while (n_left_from > 0 && n_left_to_next > 0)
  	{
  	  u32 bi0 = from[0];
  	  vlib_buffer_t * b0 = vlib_get_buffer (vm, bi0);
            u32 flow_hash0 = vnet_l2_compute_flow_hash(b0);
  
  	  to_next[0] = bi0;
  	  from += 1;
  	  to_next += 1;
  	  n_left_from -= 1;
  	  n_left_to_next -= 1;
  
  	  /* Get next node index and adj index from tunnel next_dpo */
  	  if (sw_if_index0 != vnet_buffer(b0)->sw_if_index[VLIB_TX])
  	    {
  	      sw_if_index0 = vnet_buffer(b0)->sw_if_index[VLIB_TX];
  	      hi0 = vnet_get_sup_hw_interface (vnm, sw_if_index0);
  	      t0 = &vxm->tunnels[hi0->dev_instance];
  	      /* Note: change to always set next0 if it may be set to drop */
  	      next0 = t0->next_dpo.dpoi_next_node;
  	    }
  	  vnet_buffer(b0)->ip.adj_index[VLIB_TX] = t0->next_dpo.dpoi_index;
  
            ASSERT(vec_len(t0->rewrite) == underlay_hdr_len);
            vlib_buffer_advance (b0, -underlay_hdr_len);
  
   	  u32 len0 = vlib_buffer_length_in_chain (vm, b0);
            u16 payload_l0 = clib_host_to_net_u16 (len0 - l3_len);
  
            udp_header_t * udp0;
            ip4_header_t * ip4_0;
            ip6_header_t * ip6_0;
            u8 * l3_0;
  	  if (is_ip4)
  	    {
                ip4_vxlan_header_t * rewrite = (void *)t0->rewrite;
                ip4_vxlan_header_t * hdr = vlib_buffer_get_current(b0);
                *hdr = *rewrite;
  
  	      /* Fix the IP4 checksum and length */
                ip4_0 = &hdr->ip4;
                ip4_0->length = clib_host_to_net_u16 (len0);
  
                l3_0 = (u8*)ip4_0;
  	      udp0 = &hdr->udp;
  	    }
  	  else /* ip6 path */
  	    {
                ip6_vxlan_header_t * hdr = vlib_buffer_get_current(b0);
                ip6_vxlan_header_t * rewrite = (void *) t0->rewrite;
                *hdr = *rewrite;
  
  	      /* Fix IP6 payload length */
                ip6_0 = &hdr->ip6;
  	      ip6_0->payload_length = payload_l0;
  
                l3_0 = (u8 *)ip6_0;
                udp0 = &hdr->udp;
  	    }
  
            /* Fix UDP length  and set source port */
            udp0->length = payload_l0;
            udp0->src_port = flow_hash0;
  
            if (csum_offload)
              {
                b0->flags |= csum_flags;
                vnet_buffer (b0)->l3_hdr_offset = l3_0 - b0->data;
                vnet_buffer (b0)->l4_hdr_offset = (u8 *) udp0 - b0->data;
              }
            /* IPv4 UDP checksum only if checksum offload is used */
            else if (is_ip4)
              {
                ip_csum_t sum0 = ip4_0->checksum;
                sum0 = ip_csum_update (sum0, 0, ip4_0->length, ip4_header_t,
                    length /* changed member */);
                ip4_0->checksum = ip_csum_fold (sum0);
              }
            /* IPv6 UDP checksum is mandatory */
            else
              {
                int bogus = 0;
  
                udp0->checksum = ip6_tcp_udp_icmp_compute_checksum
                  (vm, b0, ip6_0, &bogus);
                ASSERT(bogus == 0);
                if (udp0->checksum == 0)
                  udp0->checksum = 0xffff;
              }
  
  	  /* Batch stats increment on the same vxlan tunnel so counter is not
  	     incremented per packet. Note stats are still incremented for deleted
  	     and admin-down tunnel where packets are dropped. It is not worthwhile
  	     to check for this rare case and affect normal path performance. */
  	  if (PREDICT_FALSE (sw_if_index0 != stats_sw_if_index)) 
  	    {
  	      if (stats_n_packets)
                  {
                    vlib_increment_combined_counter (tx_counter, thread_index,
                        stats_sw_if_index, stats_n_packets, stats_n_bytes);
                    stats_n_bytes = stats_n_packets = 0;
                  }
  	      stats_sw_if_index = sw_if_index0;
  	    }
  	  stats_n_packets += 1;
  	  stats_n_bytes += len0;
            pkts_encapsulated ++;
  
            if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED)) 
              {
                vxlan_encap_trace_t *tr = 
                  vlib_add_trace (vm, node, b0, sizeof (*tr));
                tr->tunnel_index = t0 - vxm->tunnels;
                tr->vni = t0->vni;
              }
  	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
  					   to_next, n_left_to_next,
  					   bi0, next0);
  	}
  
        vlib_put_next_frame (vm, node, next_index, n_left_to_next);
      }
  
    /* Do we still need this now that tunnel tx stats is kept? */
    vlib_node_increment_counter (vm, node->node_index, 
                                 VXLAN_ENCAP_ERROR_ENCAPSULATED, 
                                 pkts_encapsulated);
  
    /* Increment any remaining batch stats */
    if (stats_n_packets)
      {
        vlib_increment_combined_counter (tx_counter, thread_index,
            stats_sw_if_index, stats_n_packets, stats_n_bytes);
        node->runtime_data[0] = stats_sw_if_index;
      }
  
    return from_frame->n_vectors;
  }
  
  static uword
  vxlan4_encap (vlib_main_t * vm,
  	      vlib_node_runtime_t * node,
  	      vlib_frame_t * from_frame)
  {
    /* Disable chksum offload as setup overhead in tx node is not worthwhile
       for ip4 header checksum only, unless udp checksum is also required */
    return vxlan_encap_inline (vm, node, from_frame, /* is_ip4 */ 1, 
  			     /* csum_offload */ 0);
  }
  
  static uword
  vxlan6_encap (vlib_main_t * vm,
  	      vlib_node_runtime_t * node,
  	      vlib_frame_t * from_frame)
  {
    /* Enable checksum offload for ip6 as udp checksum is mandatory, */
    return vxlan_encap_inline (vm, node, from_frame, /* is_ip4 */ 0, 
  			     /* csum_offload */ 1);
  }
  
  VLIB_REGISTER_NODE (vxlan4_encap_node) = {
    .function = vxlan4_encap,
    .name = "vxlan4-encap",
    .vector_size = sizeof (u32),
    .format_trace = format_vxlan_encap_trace,
    .type = VLIB_NODE_TYPE_INTERNAL,
    .n_errors = ARRAY_LEN(vxlan_encap_error_strings),
    .error_strings = vxlan_encap_error_strings,
    .n_next_nodes = VXLAN_ENCAP_N_NEXT,
    .next_nodes = {
          [VXLAN_ENCAP_NEXT_DROP] = "error-drop",
    },
  };
  
  VLIB_NODE_FUNCTION_MULTIARCH (vxlan4_encap_node, vxlan4_encap)
  
  VLIB_REGISTER_NODE (vxlan6_encap_node) = {
    .function = vxlan6_encap,
    .name = "vxlan6-encap",
    .vector_size = sizeof (u32),
    .format_trace = format_vxlan_encap_trace,
    .type = VLIB_NODE_TYPE_INTERNAL,
    .n_errors = ARRAY_LEN(vxlan_encap_error_strings),
    .error_strings = vxlan_encap_error_strings,
    .n_next_nodes = VXLAN_ENCAP_N_NEXT,
    .next_nodes = {
          [VXLAN_ENCAP_NEXT_DROP] = "error-drop",
    },
  };
  
  VLIB_NODE_FUNCTION_MULTIARCH (vxlan6_encap_node, vxlan6_encap)
  
  