/*
 * Copyright (c) 2016 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/ip/ip.h>
#include <vnet/dpo/mpls_disposition.h>
#include <vnet/mpls/mpls.h>

/*
 * pool of all MPLS Label DPOs
 */
mpls_disp_dpo_t *mpls_disp_dpo_pool;

static mpls_disp_dpo_t *
mpls_disp_dpo_alloc (void)
{
    mpls_disp_dpo_t *mdd;

    pool_get_aligned(mpls_disp_dpo_pool, mdd, CLIB_CACHE_LINE_BYTES);
    memset(mdd, 0, sizeof(*mdd));

    dpo_reset(&mdd->mdd_dpo);

    return (mdd);
}

static index_t
mpls_disp_dpo_get_index (mpls_disp_dpo_t *mdd)
{
    return (mdd - mpls_disp_dpo_pool);
}

index_t
mpls_disp_dpo_create (dpo_proto_t payload_proto,
                      fib_rpf_id_t rpf_id,
                      const dpo_id_t *dpo)
{
    mpls_disp_dpo_t *mdd;

    mdd = mpls_disp_dpo_alloc();

    mdd->mdd_payload_proto = payload_proto;
    mdd->mdd_rpf_id = rpf_id;

    dpo_stack(DPO_MPLS_DISPOSITION,
              mdd->mdd_payload_proto,
              &mdd->mdd_dpo,
              dpo);

    return (mpls_disp_dpo_get_index(mdd));
}

u8*
format_mpls_disp_dpo (u8 *s, va_list *args)
{
    index_t index = va_arg (*args, index_t);
    u32 indent = va_arg (*args, u32);
    mpls_disp_dpo_t *mdd;

    mdd = mpls_disp_dpo_get(index);

    s = format(s, "mpls-disposition:[%d]:[%U]",
               index,
               format_dpo_proto, mdd->mdd_payload_proto);

    s = format(s, "\n%U", format_white_space, indent);
    s = format(s, "%U", format_dpo_id, &mdd->mdd_dpo, indent+2);

    return (s);
}

static void
mpls_disp_dpo_lock (dpo_id_t *dpo)
{
    mpls_disp_dpo_t *mdd;

    mdd = mpls_disp_dpo_get(dpo->dpoi_index);

    mdd->mdd_locks++;
}

static void
mpls_disp_dpo_unlock (dpo_id_t *dpo)
{
    mpls_disp_dpo_t *mdd;

    mdd = mpls_disp_dpo_get(dpo->dpoi_index);

    mdd->mdd_locks--;

    if (0 == mdd->mdd_locks)
    {
	dpo_reset(&mdd->mdd_dpo);
	pool_put(mpls_disp_dpo_pool, mdd);
    }
}

/**
 * @brief A struct to hold tracing information for the MPLS label disposition
 * node.
 */
typedef struct mpls_label_disposition_trace_t_
{
    index_t mdd;
} mpls_label_disposition_trace_t;

always_inline uword
mpls_label_disposition_inline (vlib_main_t * vm,
                              vlib_node_runtime_t * node,
                              vlib_frame_t * from_frame,
                              u8 payload_is_ip4,
                              u8 payload_is_ip6)
{
    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 >= 4 && n_left_to_next >= 2)
        {
            mpls_disp_dpo_t *mdd0, *mdd1;
            u32 bi0, mddi0, bi1, mddi1;
            vlib_buffer_t * b0, *b1;
            u32 next0, next1;

            bi0 = to_next[0] = from[0];
            bi1 = to_next[1] = from[1];

            /* 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 (ip6_header_t), STORE);
                CLIB_PREFETCH (p3->data, sizeof (ip6_header_t), STORE);
            }

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

            b0 = vlib_get_buffer (vm, bi0);
            b1 = vlib_get_buffer (vm, bi1);

            /* dst lookup was done by ip4 lookup */
            mddi0 = vnet_buffer(b0)->ip.adj_index[VLIB_TX];
            mddi1 = vnet_buffer(b1)->ip.adj_index[VLIB_TX];
            mdd0 = mpls_disp_dpo_get(mddi0);
            mdd1 = mpls_disp_dpo_get(mddi1);

            if (payload_is_ip4)
            {
                /*
                 * decrement the TTL on ingress to the LSP
                 */
            }
            else if (payload_is_ip6)
            {
                /*
                 * decrement the TTL on ingress to the LSP
                 */
            }
 
            next0 = mdd0->mdd_dpo.dpoi_next_node;
            next1 = mdd1->mdd_dpo.dpoi_next_node;
            vnet_buffer(b0)->ip.adj_index[VLIB_TX] = mdd0->mdd_dpo.dpoi_index;
            vnet_buffer(b1)->ip.adj_index[VLIB_TX] = mdd1->mdd_dpo.dpoi_index;
            vnet_buffer(b0)->ip.rpf_id = mdd0->mdd_rpf_id;
            vnet_buffer(b1)->ip.rpf_id = mdd1->mdd_rpf_id;

            if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED))
            {
                mpls_label_disposition_trace_t *tr =
                    vlib_add_trace (vm, node, b0, sizeof (*tr));

                tr->mdd = mddi0;
            }
            if (PREDICT_FALSE(b1->flags & VLIB_BUFFER_IS_TRACED))
            {
                mpls_label_disposition_trace_t *tr =
                    vlib_add_trace (vm, node, b1, sizeof (*tr));
                tr->mdd = mddi1;
            }

            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)
        {
            mpls_disp_dpo_t *mdd0;
            vlib_buffer_t * b0;
            u32 bi0, mddi0;
            u32 next0;

            bi0 = from[0];
            to_next[0] = bi0;
            from += 1;
            to_next += 1;
            n_left_from -= 1;
            n_left_to_next -= 1;

            b0 = vlib_get_buffer (vm, bi0);

            /* dst lookup was done by ip4 lookup */
            mddi0 = vnet_buffer(b0)->ip.adj_index[VLIB_TX];
            mdd0 = mpls_disp_dpo_get(mddi0);

            if (payload_is_ip4)
            {
                /*
                 * decrement the TTL on ingress to the LSP
                 */
            }
            else if (payload_is_ip6)
            {
                /*
                 * decrement the TTL on ingress to the LSP
                 */
            }
            else
            {
            }

            next0 = mdd0->mdd_dpo.dpoi_next_node;
            vnet_buffer(b0)->ip.adj_index[VLIB_TX] = mdd0->mdd_dpo.dpoi_index;
            vnet_buffer(b0)->ip.rpf_id = mdd0->mdd_rpf_id;

            if (PREDICT_FALSE(b0->flags & VLIB_BUFFER_IS_TRACED))
            {
                mpls_label_disposition_trace_t *tr =
                    vlib_add_trace (vm, node, b0, sizeof (*tr));
                tr->mdd = mddi0;
            }

            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);
    }
    return from_frame->n_vectors;
}

static u8 *
format_mpls_label_disposition_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 *);
    CLIB_UNUSED (mpls_label_disposition_trace_t * t);

    t = va_arg (*args, mpls_label_disposition_trace_t *);

    s = format(s, "disp:%d", t->mdd);
    return (s);
}

static uword
ip4_mpls_label_disposition (vlib_main_t * vm,
                           vlib_node_runtime_t * node,
                           vlib_frame_t * frame)
{
    return (mpls_label_disposition_inline(vm, node, frame, 1, 0));
}

VLIB_REGISTER_NODE (ip4_mpls_label_disposition_node) = {
    .function = ip4_mpls_label_disposition,
    .name = "ip4-mpls-label-disposition",
    .vector_size = sizeof (u32),

    .format_trace = format_mpls_label_disposition_trace,
    .n_next_nodes = 1,
    .next_nodes = {
        [0] = "ip4-drop",
    }
};
VLIB_NODE_FUNCTION_MULTIARCH (ip4_mpls_label_disposition_node,
                              ip4_mpls_label_disposition)

static uword
ip6_mpls_label_disposition (vlib_main_t * vm,
                           vlib_node_runtime_t * node,
                           vlib_frame_t * frame)
{
    return (mpls_label_disposition_inline(vm, node, frame, 0, 1));
}

VLIB_REGISTER_NODE (ip6_mpls_label_disposition_node) = {
    .function = ip6_mpls_label_disposition,
    .name = "ip6-mpls-label-disposition",
    .vector_size = sizeof (u32),

    .format_trace = format_mpls_label_disposition_trace,
    .n_next_nodes = 1,
    .next_nodes = {
        [0] = "ip6-drop",
    }
};
VLIB_NODE_FUNCTION_MULTIARCH (ip6_mpls_label_disposition_node,
                              ip6_mpls_label_disposition)

static void
mpls_disp_dpo_mem_show (void)
{
    fib_show_memory_usage("MPLS label",
			  pool_elts(mpls_disp_dpo_pool),
			  pool_len(mpls_disp_dpo_pool),
			  sizeof(mpls_disp_dpo_t));
}

const static dpo_vft_t mdd_vft = {
    .dv_lock = mpls_disp_dpo_lock,
    .dv_unlock = mpls_disp_dpo_unlock,
    .dv_format = format_mpls_disp_dpo,
    .dv_mem_show = mpls_disp_dpo_mem_show,
};

const static char* const mpls_label_disp_ip4_nodes[] =
{
    "ip4-mpls-label-disposition",
    NULL,
};
const static char* const mpls_label_disp_ip6_nodes[] =
{
    "ip6-mpls-label-disposition",
    NULL,
};
const static char* const * const mpls_label_disp_nodes[DPO_PROTO_NUM] =
{
    [DPO_PROTO_IP4]  = mpls_label_disp_ip4_nodes,
    [DPO_PROTO_IP6]  = mpls_label_disp_ip6_nodes,
};


void
mpls_disp_dpo_module_init (void)
{
    dpo_register(DPO_MPLS_DISPOSITION, &mdd_vft, mpls_label_disp_nodes);
}