/*
 * Copyright (c) 2018 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-gbp/vxlan_gbp.h>
#include <vnet/qos/qos_types.h>
#include <vnet/adj/rewrite.h>

/* Statistics (not all errors) */
#define foreach_vxlan_gbp_encap_error    \
_(ENCAPSULATED, "good packets encapsulated")

static char *vxlan_gbp_encap_error_strings[] = {
#define _(sym,string) string,
  foreach_vxlan_gbp_encap_error
#undef _
};

typedef enum
{
#define _(sym,str) VXLAN_GBP_ENCAP_ERROR_##sym,
  foreach_vxlan_gbp_encap_error
#undef _
    VXLAN_GBP_ENCAP_N_ERROR,
} vxlan_gbp_encap_error_t;

typedef enum
{
  VXLAN_GBP_ENCAP_NEXT_DROP,
  VXLAN_GBP_ENCAP_N_NEXT,
} vxlan_gbp_encap_next_t;

typedef struct
{
  u32 tunnel_index;
  u32 vni;
  u16 sclass;
  u8 flags;
} vxlan_gbp_encap_trace_t;

u8 *
format_vxlan_gbp_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_gbp_encap_trace_t *t = va_arg (*args, vxlan_gbp_encap_trace_t *);

  s =
    format (s,
	    "VXLAN_GBP encap to vxlan_gbp_tunnel%d vni %d sclass %d flags %d",
	    t->tunnel_index, t->vni, t->sclass, t->flags);
  return s;
}

always_inline uword
vxlan_gbp_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_gbp_main_t *vxm = &vxlan_gbp_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 sw_if_index0 = 0, sw_if_index1 = 0;
  u32 next0 = 0, next1 = 0;
  vxlan_gbp_tunnel_t *t0 = NULL, *t1 = NULL;
  index_t dpoi_idx0 = INDEX_INVALID, dpoi_idx1 = INDEX_INVALID;

  from = vlib_frame_vector_args (from_frame);
  n_left_from = from_frame->n_vectors;

  next_index = node->cached_next_index;

  STATIC_ASSERT_SIZEOF (ip6_vxlan_gbp_header_t, 56);
  STATIC_ASSERT_SIZEOF (ip4_vxlan_gbp_header_t, 36);

  u8 const underlay_hdr_len = is_ip4 ?
    sizeof (ip4_vxlan_gbp_header_t) : sizeof (ip6_vxlan_gbp_header_t);
  u8 const rw_hdr_offset = sizeof t0->rewrite_data - underlay_hdr_len;
  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 = to_next[0] = from[0];
	  u32 bi1 = to_next[1] = from[1];
	  from += 2;
	  to_next += 2;
	  n_left_to_next -= 2;
	  n_left_from -= 2;

	  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);

	  /* 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];
	      vnet_hw_interface_t *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 set to drop */
	      next0 = t0->next_dpo.dpoi_next_node;
	      dpoi_idx0 = 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])
	    {
	      if (sw_if_index0 == vnet_buffer (b1)->sw_if_index[VLIB_TX])
		{
		  sw_if_index1 = sw_if_index0;
		  t1 = t0;
		  next1 = next0;
		  dpoi_idx1 = dpoi_idx0;
		}
	      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);
		  t1 = &vxm->tunnels[hi1->dev_instance];
		  /* Note: change to always set next1 if it may set to drop */
		  next1 = t1->next_dpo.dpoi_next_node;
		  dpoi_idx1 = t1->next_dpo.dpoi_index;
		}
	    }

	  vnet_buffer (b0)->ip.adj_index[VLIB_TX] = dpoi_idx0;
	  vnet_buffer (b1)->ip.adj_index[VLIB_TX] = dpoi_idx1;

	  ASSERT (t0->rewrite_header.data_bytes == underlay_hdr_len);
	  ASSERT (t1->rewrite_header.data_bytes == 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);

	  void *underlay0 = vlib_buffer_get_current (b0);
	  void *underlay1 = vlib_buffer_get_current (b1);

	  /* vnet_rewrite_two_header writes only in (uword) 8 bytes chunks
	   * and discards the first 4 bytes of the (36 bytes ip4 underlay)  rewrite
	   * use memcpy as a workaround */
	  clib_memcpy_fast (underlay0,
			    t0->rewrite_header.data + rw_hdr_offset,
			    underlay_hdr_len);
	  clib_memcpy_fast (underlay1,
			    t1->rewrite_header.data + rw_hdr_offset,
			    underlay_hdr_len);

	  ip4_header_t *ip4_0, *ip4_1;
	  qos_bits_t ip4_0_tos = 0, ip4_1_tos = 0;
	  ip6_header_t *ip6_0, *ip6_1;
	  udp_header_t *udp0, *udp1;
	  vxlan_gbp_header_t *vxlan_gbp0, *vxlan_gbp1;
	  u8 *l3_0, *l3_1;
	  if (is_ip4)
	    {
	      ip4_vxlan_gbp_header_t *hdr0 = underlay0;
	      ip4_vxlan_gbp_header_t *hdr1 = underlay1;

	      /* 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);

	      if (PREDICT_FALSE (b0->flags & VNET_BUFFER_F_QOS_DATA_VALID))
		{
		  ip4_0_tos = vnet_buffer2 (b0)->qos.bits;
		  ip4_0->tos = ip4_0_tos;
		}
	      if (PREDICT_FALSE (b1->flags & VNET_BUFFER_F_QOS_DATA_VALID))
		{
		  ip4_1_tos = vnet_buffer2 (b1)->qos.bits;
		  ip4_1->tos = ip4_1_tos;
		}

	      l3_0 = (u8 *) ip4_0;
	      l3_1 = (u8 *) ip4_1;
	      udp0 = &hdr0->udp;
	      udp1 = &hdr1->udp;
	      vxlan_gbp0 = &hdr0->vxlan_gbp;
	      vxlan_gbp1 = &hdr1->vxlan_gbp;
	    }
	  else			/* ipv6 */
	    {
	      ip6_vxlan_gbp_header_t *hdr0 = underlay0;
	      ip6_vxlan_gbp_header_t *hdr1 = underlay1;

	      /* 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;
	      vxlan_gbp0 = &hdr0->vxlan_gbp;
	      vxlan_gbp1 = &hdr1->vxlan_gbp;
	    }

	  /* 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;

	  /* set source class and gpflags */
	  vxlan_gbp0->gpflags = vnet_buffer2 (b0)->gbp.flags;
	  vxlan_gbp1->gpflags = vnet_buffer2 (b1)->gbp.flags;
	  vxlan_gbp0->sclass =
	    clib_host_to_net_u16 (vnet_buffer2 (b0)->gbp.sclass);
	  vxlan_gbp1->sclass =
	    clib_host_to_net_u16 (vnet_buffer2 (b1)->gbp.sclass);

	  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 */ );
	      if (PREDICT_FALSE (ip4_0_tos))
		{
		  sum0 = ip_csum_update (sum0, 0, ip4_0_tos, ip4_header_t,
					 tos /* 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 */ );
	      if (PREDICT_FALSE (ip4_1_tos))
		{
		  sum1 = ip_csum_update (sum1, 0, ip4_1_tos, ip4_header_t,
					 tos /* 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;
	    }

	  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_gbp_encap_trace_t *tr =
		vlib_add_trace (vm, node, b0, sizeof (*tr));
	      tr->tunnel_index = t0 - vxm->tunnels;
	      tr->vni = t0->vni;
	      tr->sclass = vnet_buffer2 (b0)->gbp.sclass;
	      tr->flags = vnet_buffer2 (b0)->gbp.flags;
	    }

	  if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
	    {
	      vxlan_gbp_encap_trace_t *tr =
		vlib_add_trace (vm, node, b1, sizeof (*tr));
	      tr->tunnel_index = t1 - vxm->tunnels;
	      tr->vni = t1->vni;
	      tr->sclass = vnet_buffer2 (b1)->gbp.sclass;
	      tr->flags = vnet_buffer2 (b1)->gbp.flags;
	    }

	  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 = to_next[0] = from[0];
	  from += 1;
	  to_next += 1;
	  n_left_from -= 1;
	  n_left_to_next -= 1;

	  vlib_buffer_t *b0 = vlib_get_buffer (vm, bi0);
	  u32 flow_hash0 = vnet_l2_compute_flow_hash (b0);

	  /* 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];
	      vnet_hw_interface_t *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;
	      dpoi_idx0 = t0->next_dpo.dpoi_index;
	    }
	  vnet_buffer (b0)->ip.adj_index[VLIB_TX] = dpoi_idx0;

	  ASSERT (t0->rewrite_header.data_bytes == underlay_hdr_len);

	  vlib_buffer_advance (b0, -underlay_hdr_len);
	  void *underlay0 = vlib_buffer_get_current (b0);

	  /* vnet_rewrite_one_header writes only in (uword) 8 bytes chunks
	   * and discards the first 4 bytes of the (36 bytes ip4 underlay)  rewrite
	   * use memcpy as a workaround */
	  clib_memcpy_fast (underlay0,
			    t0->rewrite_header.data + rw_hdr_offset,
			    underlay_hdr_len);

	  u32 len0 = vlib_buffer_length_in_chain (vm, b0);
	  u16 payload_l0 = clib_host_to_net_u16 (len0 - l3_len);

	  vxlan_gbp_header_t *vxlan_gbp0;
	  udp_header_t *udp0;
	  ip4_header_t *ip4_0;
	  qos_bits_t ip4_0_tos = 0;
	  ip6_header_t *ip6_0;
	  u8 *l3_0;
	  if (is_ip4)
	    {
	      ip4_vxlan_gbp_header_t *hdr = underlay0;

	      /* Fix the IP4 checksum and length */
	      ip4_0 = &hdr->ip4;
	      ip4_0->length = clib_host_to_net_u16 (len0);

	      if (PREDICT_FALSE (b0->flags & VNET_BUFFER_F_QOS_DATA_VALID))
		{
		  ip4_0_tos = vnet_buffer2 (b0)->qos.bits;
		  ip4_0->tos = ip4_0_tos;
		}

	      l3_0 = (u8 *) ip4_0;
	      udp0 = &hdr->udp;
	      vxlan_gbp0 = &hdr->vxlan_gbp;
	    }
	  else			/* ip6 path */
	    {
	      ip6_vxlan_gbp_header_t *hdr = underlay0;

	      /* Fix IP6 payload length */
	      ip6_0 = &hdr->ip6;
	      ip6_0->payload_length = payload_l0;

	      l3_0 = (u8 *) ip6_0;
	      udp0 = &hdr->udp;
	      vxlan_gbp0 = &hdr->vxlan_gbp;
	    }

	  /* Fix UDP length  and set source port */
	  udp0->length = payload_l0;
	  udp0->src_port = flow_hash0;

	  /* set source class and gpflags */
	  vxlan_gbp0->gpflags = vnet_buffer2 (b0)->gbp.flags;
	  vxlan_gbp0->sclass =
	    clib_host_to_net_u16 (vnet_buffer2 (b0)->gbp.sclass);

	  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 */ );
	      if (PREDICT_FALSE (ip4_0_tos))
		{
		  sum0 = ip_csum_update (sum0, 0, ip4_0_tos, ip4_header_t,
					 tos /* 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;
	    }

	  vlib_increment_combined_counter (tx_counter, thread_index,
					   sw_if_index0, 1, len0);
	  pkts_encapsulated++;

	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
	    {
	      vxlan_gbp_encap_trace_t *tr =
		vlib_add_trace (vm, node, b0, sizeof (*tr));
	      tr->tunnel_index = t0 - vxm->tunnels;
	      tr->vni = t0->vni;
	      tr->sclass = vnet_buffer2 (b0)->gbp.sclass;
	      tr->flags = vnet_buffer2 (b0)->gbp.flags;
	    }
	  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_GBP_ENCAP_ERROR_ENCAPSULATED,
			       pkts_encapsulated);

  return from_frame->n_vectors;
}

static uword
vxlan4_gbp_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_gbp_encap_inline (vm, node, from_frame, /* is_ip4 */ 1,
				 /* csum_offload */ 0);
}

static uword
vxlan6_gbp_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_gbp_encap_inline (vm, node, from_frame, /* is_ip4 */ 0,
				 /* csum_offload */ 1);
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (vxlan4_gbp_encap_node) =
{
  .function = vxlan4_gbp_encap,
  .name = "vxlan4-gbp-encap",
  .vector_size = sizeof (u32),
  .format_trace = format_vxlan_gbp_encap_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN (vxlan_gbp_encap_error_strings),
  .error_strings = vxlan_gbp_encap_error_strings,
  .n_next_nodes = VXLAN_GBP_ENCAP_N_NEXT,
  .next_nodes = {
    [VXLAN_GBP_ENCAP_NEXT_DROP] = "error-drop",
  },
};

VLIB_NODE_FUNCTION_MULTIARCH (vxlan4_gbp_encap_node, vxlan4_gbp_encap)

VLIB_REGISTER_NODE (vxlan6_gbp_encap_node) =
{
  .function = vxlan6_gbp_encap,
  .name = "vxlan6-gbp-encap",
  .vector_size = sizeof (u32),
  .format_trace = format_vxlan_gbp_encap_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN (vxlan_gbp_encap_error_strings),
  .error_strings = vxlan_gbp_encap_error_strings,
  .n_next_nodes = VXLAN_GBP_ENCAP_N_NEXT,
  .next_nodes = {
    [VXLAN_GBP_ENCAP_NEXT_DROP] = "error-drop",
  },
};

VLIB_NODE_FUNCTION_MULTIARCH (vxlan6_gbp_encap_node, vxlan6_gbp_encap)
/* *INDENT-ON* */

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