/*
 * nsh_output.c: NSH Adj rewrite
 *
 * Copyright (c) 2017-2019 Intel 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 <vlib/vlib.h>
#include <vnet/ip/ip.h>
#include <nsh/nsh.h>

typedef struct {
  /* Adjacency taken. */
  u32 adj_index;
  u32 flow_hash;

  /* Packet data, possibly *after* rewrite. */
  u8 packet_data[64 - 1*sizeof(u32)];
} nsh_output_trace_t;

#define foreach_nsh_output_next        	\
_(DROP, "error-drop")            \
_(INTERFACE, "interface-output" )

typedef enum {
#define _(s,n) NSH_OUTPUT_NEXT_##s,
  foreach_nsh_output_next
#undef _
  NSH_OUTPUT_N_NEXT,
} nsh_output_next_t;

static u8 *
format_nsh_output_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 *);
  nsh_output_trace_t * t = va_arg (*args, nsh_output_trace_t *);
  uword indent = format_get_indent (s);

  s = format (s, "adj-idx %d : %U flow hash: 0x%08x",
              t->adj_index,
              format_ip_adjacency, t->adj_index, FORMAT_IP_ADJACENCY_NONE,
              t->flow_hash);
  s = format (s, "\n%U%U",
              format_white_space, indent,
              format_ip_adjacency_packet_data,
              t->adj_index, t->packet_data, sizeof (t->packet_data));
  return s;
}

static inline uword
nsh_output_inline (vlib_main_t * vm,
                   vlib_node_runtime_t * node,
                   vlib_frame_t * from_frame,
                   int is_midchain)
{
  u32 n_left_from, next_index, * from, * to_next, thread_index;
  vlib_node_runtime_t * error_node;
  u32 n_left_to_next;
  nsh_main_t *nm;

  thread_index = vlib_get_thread_index();
  error_node = vlib_node_get_runtime (vm, nsh_eth_output_node.index);
  from = vlib_frame_vector_args (from_frame);
  n_left_from = from_frame->n_vectors;
  next_index = node->cached_next_index;
  nm = &nsh_main;

  while (n_left_from > 0)
    {
      vlib_get_next_frame (vm, node, next_index,
                           to_next, n_left_to_next);

      while (n_left_from >= 4 && n_left_to_next >= 2)
        {
          ip_adjacency_t * adj0;
          nsh_base_header_t *hdr0;
          ethernet_header_t * eth_hdr0;
          vlib_buffer_t * p0;
          u32 pi0, adj_index0, next0, error0;

          ip_adjacency_t * adj1;
          nsh_base_header_t *hdr1;
          ethernet_header_t * eth_hdr1;
          vlib_buffer_t * p1;
          u32 pi1, adj_index1, next1, error1;
          int pkt_len0, pkt_len1;
          word rw_len0, rw_len1;

          /* 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, STORE);
            vlib_prefetch_buffer_header (p3, STORE);

            CLIB_PREFETCH (p2->data, sizeof (hdr0[0]), STORE);
            CLIB_PREFETCH (p3->data, sizeof (hdr1[0]), STORE);
          }

          pi0 = to_next[0] = from[0];
          pi1 = to_next[1] = from[1];

          from += 2;
          n_left_from -= 2;
          to_next += 2;
          n_left_to_next -= 2;

          p0 = vlib_get_buffer (vm, pi0);
          p1 = vlib_get_buffer (vm, pi1);

          adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];
          adj_index1 = vnet_buffer (p1)->ip.adj_index[VLIB_TX];

          adj0 = adj_get(adj_index0);
          adj1 = adj_get(adj_index1);
          hdr0 = vlib_buffer_get_current (p0);
          hdr1 = vlib_buffer_get_current (p1);

          /* Guess we are only writing on simple Ethernet header. */
          vnet_rewrite_two_headers (adj0[0], adj1[0], hdr0, hdr1,
                                   sizeof (ethernet_header_t));

          eth_hdr0 = (ethernet_header_t*)((u8 *)hdr0-sizeof(ethernet_header_t));
          eth_hdr0->type = clib_host_to_net_u16(ETHERNET_TYPE_NSH);
          eth_hdr1 = (ethernet_header_t*)((u8 *)hdr1-sizeof(ethernet_header_t));
          eth_hdr1->type = clib_host_to_net_u16(ETHERNET_TYPE_NSH);

          /* Update packet buffer attributes/set output interface. */
          rw_len0 = adj0[0].rewrite_header.data_bytes;
          rw_len1 = adj1[0].rewrite_header.data_bytes;
          pkt_len0 = vlib_buffer_length_in_chain (vm, p0);
          pkt_len1 = vlib_buffer_length_in_chain (vm, p1);

          /* Bump the adj counters for packet and bytes */
          if (adj_index0 == adj_index1)
          {
            vlib_increment_combined_counter (&adjacency_counters, thread_index, adj_index0, 2,
               pkt_len0 + rw_len0 + pkt_len1 + rw_len1);
          }
          else
          {
            vlib_increment_combined_counter (&adjacency_counters, thread_index, adj_index0, 1,
               pkt_len0 + rw_len0);
            vlib_increment_combined_counter (&adjacency_counters, thread_index, adj_index1, 1,
               pkt_len1 + rw_len1);
          }
          /* Check MTU of outgoing interface. */
          if (PREDICT_TRUE(pkt_len0 <=
                           adj0[0].rewrite_header.max_l3_packet_bytes))
            {
              vlib_buffer_advance (p0, -rw_len0);

              vnet_buffer (p0)->sw_if_index[VLIB_TX] =
                  adj0[0].rewrite_header.sw_if_index;
              next0 = NSH_OUTPUT_NEXT_INTERFACE;
              error0 = IP4_ERROR_NONE;

              if (PREDICT_FALSE(adj0[0].rewrite_header.flags & VNET_REWRITE_HAS_FEATURES))
                vnet_feature_arc_start (nm->output_feature_arc_index,
                                        adj0[0].rewrite_header.sw_if_index,
                                        &next0, p0);
            }
          else
            {
              error0 = IP4_ERROR_MTU_EXCEEDED;
              next0 = NSH_OUTPUT_NEXT_DROP;
            }
          if (PREDICT_TRUE(pkt_len1 <=
                           adj1[0].rewrite_header.max_l3_packet_bytes))
            {
              vlib_buffer_advance (p1, -rw_len1);

              vnet_buffer (p1)->sw_if_index[VLIB_TX] =
                  adj1[0].rewrite_header.sw_if_index;
              next1 = NSH_OUTPUT_NEXT_INTERFACE;
              error1 = IP4_ERROR_NONE;

              if (PREDICT_FALSE(adj1[0].rewrite_header.flags & VNET_REWRITE_HAS_FEATURES))
                vnet_feature_arc_start (nm->output_feature_arc_index,
                                        adj1[0].rewrite_header.sw_if_index,
                                        &next1, p1);
            }
          else
            {
              error1 = IP4_ERROR_MTU_EXCEEDED;
              next1 = NSH_OUTPUT_NEXT_DROP;
            }
          if (is_midchain)
          {
              adj0->sub_type.midchain.fixup_func
                (vm, adj0, p0, adj0->sub_type.midchain.fixup_data);
              adj1->sub_type.midchain.fixup_func
                (vm, adj1, p1, adj1->sub_type.midchain.fixup_data);
          }

          p0->error = error_node->errors[error0];
          p1->error = error_node->errors[error1];

          if (PREDICT_FALSE(p0->flags & VLIB_BUFFER_IS_TRACED))
            {
              nsh_output_trace_t *tr = vlib_add_trace (vm, node,
                                                        p0, sizeof (*tr));
              tr->adj_index = vnet_buffer(p0)->ip.adj_index[VLIB_TX];
              tr->flow_hash = vnet_buffer(p0)->ip.flow_hash;
            }
          if (PREDICT_FALSE(p1->flags & VLIB_BUFFER_IS_TRACED))
            {
              nsh_output_trace_t *tr = vlib_add_trace (vm, node,
                                                        p1, sizeof (*tr));
              tr->adj_index = vnet_buffer(p1)->ip.adj_index[VLIB_TX];
              tr->flow_hash = vnet_buffer(p1)->ip.flow_hash;
            }

          vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
                                           to_next, n_left_to_next,
                                           pi0, pi1, next0, next1);
        }

      while (n_left_from > 0 && n_left_to_next > 0)
        {
          ip_adjacency_t * adj0;
          nsh_base_header_t *hdr0;
          ethernet_header_t * eth_hdr0;
          vlib_buffer_t * p0;
          u32 pi0, adj_index0, next0, error0;
          int pkt_len0;
          word rw_len0;

          pi0 = to_next[0] = from[0];

          p0 = vlib_get_buffer (vm, pi0);

          adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];

          adj0 = adj_get(adj_index0);
          hdr0 = vlib_buffer_get_current (p0);

          /* Guess we are only writing on simple Ethernet header. */
          vnet_rewrite_one_header (adj0[0], hdr0,
                                   sizeof (ethernet_header_t));

          eth_hdr0 = (ethernet_header_t*)((u8 *)hdr0-sizeof(ethernet_header_t));
          eth_hdr0->type = clib_host_to_net_u16(ETHERNET_TYPE_NSH);

          /* Update packet buffer attributes/set output interface. */
          rw_len0 = adj0[0].rewrite_header.data_bytes;
          pkt_len0 = vlib_buffer_length_in_chain (vm, p0);

          vlib_increment_combined_counter (&adjacency_counters, thread_index, adj_index0, 1,
               pkt_len0 + rw_len0);

          /* Check MTU of outgoing interface. */
          if (PREDICT_TRUE(pkt_len0 <= adj0[0].rewrite_header.max_l3_packet_bytes))
            {
              vlib_buffer_advance (p0, -rw_len0);

              vnet_buffer (p0)->sw_if_index[VLIB_TX] =
                  adj0[0].rewrite_header.sw_if_index;
              next0 = NSH_OUTPUT_NEXT_INTERFACE;
              error0 = IP4_ERROR_NONE;

              if (PREDICT_FALSE(adj0[0].rewrite_header.flags & VNET_REWRITE_HAS_FEATURES))
                vnet_feature_arc_start (nm->output_feature_arc_index,
                                        adj0[0].rewrite_header.sw_if_index,
                                        &next0, p0);
            }
          else
            {
              error0 = IP4_ERROR_MTU_EXCEEDED;
              next0 = NSH_OUTPUT_NEXT_DROP;
            }
          if (is_midchain)
          {
              adj0->sub_type.midchain.fixup_func
                (vm, adj0, p0, adj0->sub_type.midchain.fixup_data);
          }

          p0->error = error_node->errors[error0];

          from += 1;
          n_left_from -= 1;
          to_next += 1;
          n_left_to_next -= 1;

          if (PREDICT_FALSE(p0->flags & VLIB_BUFFER_IS_TRACED))
            {
              nsh_output_trace_t *tr = vlib_add_trace (vm, node,
                                                        p0, sizeof (*tr));
              tr->adj_index = vnet_buffer(p0)->ip.adj_index[VLIB_TX];
              tr->flow_hash = vnet_buffer(p0)->ip.flow_hash;
            }

          vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
                                           to_next, n_left_to_next,
                                           pi0, next0);
        }

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  return from_frame->n_vectors;
}

typedef enum nsh_midchain_next_t_
{
    NSH_MIDCHAIN_NEXT_DROP,
} nsh_midchain_next_t;

VLIB_NODE_FN (nsh_eth_output_node) (vlib_main_t * vm,
                vlib_node_runtime_t * node,
                vlib_frame_t * from_frame)
{
    return (nsh_output_inline(vm, node, from_frame, /* is_midchain */ 0));
}

VLIB_REGISTER_NODE (nsh_eth_output_node) = {
  .name = "nsh-eth-output",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),
  .n_next_nodes = NSH_OUTPUT_N_NEXT,
  .next_nodes = {
#define _(s,n) [NSH_OUTPUT_NEXT_##s] = n,
    foreach_nsh_output_next
#undef _
  },

  .format_trace = format_nsh_output_trace,
};

VLIB_NODE_FN (nsh_midchain_node) (vlib_main_t * vm,
               vlib_node_runtime_t * node,
               vlib_frame_t * from_frame)
{
    return (nsh_output_inline(vm, node, from_frame, /* is_midchain */ 1));
}

VLIB_REGISTER_NODE (nsh_midchain_node) = {
  .name = "nsh-midchain",
  .vector_size = sizeof (u32),
  .format_trace = format_nsh_output_trace,
  .n_next_nodes = 1,
  .next_nodes = {
      [NSH_MIDCHAIN_NEXT_DROP] = "error-drop",
  },
};

/* Built-in nsh tx feature path definition */
VNET_FEATURE_INIT (nsh_interface_output, static) = {
  .arc_name = "nsh-eth-output",
  .node_name = "interface-output",
  .runs_before = 0, /* not before any other features */
};

/* Built-in ip4 tx feature path definition */
VNET_FEATURE_ARC_INIT (nsh_eth_output, static) =
{
  .arc_name  = "nsh-eth-output",
  .start_nodes = VNET_FEATURES ("nsh-midchain"),
};

VNET_FEATURE_INIT (nsh_eth_tx_drop, static) =
{
  .arc_name = "nsh-eth-output",
  .node_name = "error-drop",
  .runs_before = 0,     /* not before any other features */
};
/**
 * @brief Next index values from the NSH incomplete adj node
 */
#define foreach_nsh_adj_incomplete_next       	\
_(DROP, "error-drop")                   \
_(IP4,  "ip4-arp")                      \
_(IP6,  "ip6-discover-neighbor")

typedef enum {
#define _(s,n) NSH_ADJ_INCOMPLETE_NEXT_##s,
  foreach_nsh_adj_incomplete_next
#undef _
  NSH_ADJ_INCOMPLETE_N_NEXT,
} nsh_adj_incomplete_next_t;

/**
 * @brief A struct to hold tracing information for the NSH label imposition
 * node.
 */
typedef struct nsh_adj_incomplete_trace_t_
{
    u32 next;
} nsh_adj_incomplete_trace_t;


/**
 * @brief Graph node for incomplete NSH adjacency.
 * This node will push traffic to either the v4-arp or v6-nd node
 * based on the next-hop proto of the adj.
 * We pay a cost for this 'routing' node, but an incomplete adj is the
 * exception case.
 */
VLIB_NODE_FN (nsh_adj_incomplete_node) (vlib_main_t * vm,
                     vlib_node_runtime_t * node,
                     vlib_frame_t * from_frame)
{
  u32 n_left_from, next_index, * from, * to_next;

  from = vlib_frame_vector_args (from_frame);
  n_left_from = from_frame->n_vectors;
  next_index = node->cached_next_index;

  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 > 0 && n_left_to_next > 0)
        {
          u32 pi0, next0, adj_index0;
          ip_adjacency_t * adj0;
          vlib_buffer_t * p0;

          pi0 = to_next[0] = from[0];
          p0 = vlib_get_buffer (vm, pi0);
          from += 1;
          n_left_from -= 1;
          to_next += 1;
          n_left_to_next -= 1;

          adj_index0 = vnet_buffer (p0)->ip.adj_index[VLIB_TX];

          adj0 = adj_get(adj_index0);

          if (PREDICT_TRUE(FIB_PROTOCOL_IP4 == adj0->ia_nh_proto))
          {
              next0 = NSH_ADJ_INCOMPLETE_NEXT_IP4;
          }
          else
          {
              next0 = NSH_ADJ_INCOMPLETE_NEXT_IP6;
          }

          if (PREDICT_FALSE(p0->flags & VLIB_BUFFER_IS_TRACED))
          {
              nsh_adj_incomplete_trace_t *tr =
                 vlib_add_trace (vm, node, p0, sizeof (*tr));
              tr->next = next0;
          }

          vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
                                           to_next, n_left_to_next,
                                           pi0, next0);
        }

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  return from_frame->n_vectors;
}

static u8 *
format_nsh_adj_incomplete_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 *);
    nsh_adj_incomplete_trace_t * t;
    uword indent;

    t = va_arg (*args, nsh_adj_incomplete_trace_t *);
    indent = format_get_indent (s);

    s = format (s, "%Unext:%d",
                format_white_space, indent,
                t->next);
    return (s);
}

VLIB_REGISTER_NODE (nsh_adj_incomplete_node) = {
  .name = "nsh-adj-incomplete",
  .format_trace = format_nsh_adj_incomplete_trace,
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),
  .n_next_nodes = NSH_ADJ_INCOMPLETE_N_NEXT,
  .next_nodes = {
#define _(s,n) [NSH_ADJ_INCOMPLETE_NEXT_##s] = n,
    foreach_nsh_adj_incomplete_next
#undef _
  },
};