l2t_ip6.c

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/*
 * 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 <vnet/vnet.h>
#include <vnet/ip/ip.h>
#include <vnet/ethernet/ethernet.h>

#if DPDK == 0
#include <vnet/devices/pci/ixgev.h>
#include <vnet/devices/pci/ixge.h>
#include <vnet/devices/pci/ige.h>
#include <vnet/devices/pci/vice.h>
#else
#include <vnet/devices/dpdk/dpdk.h>
#endif

#include <vppinfra/error.h>
#include <vppinfra/hash.h>
#include <app/l2t.h>

l2t_main_t l2t_main;

/* Statistics (not really errors) */
#define foreach_l2t_ip6_error                                   \
_(USER_TO_NETWORK, "User (v6) to L2 network pkts")              \
_(SESSION_ID_MISMATCH, "l2tpv3 local session id mismatches")    \
_(COOKIE_MISMATCH, "l2tpv3 local cookie mismatches")  

static char * l2t_ip6_error_strings[] = {
#define _(sym,string) string,
  foreach_l2t_ip6_error
#undef _
};

typedef enum {
#define _(sym,str) L2T_IP6_ERROR_##sym,
    foreach_l2t_ip6_error
#undef _
    L2T_IP6_N_ERROR,
} l2t_ip6_error_t;

/*
 * Packets go to ip6-input when they don't match a mapping, 
 * example: v6 neighbor discovery. They go to ip4-input
 * when they do match, and are decapsulated.
 */
typedef enum { 
    L2T_IP6_NEXT_DROP,
    L2T_IP6_NEXT_IP6_INPUT,
    L2T_IP6_N_NEXT,
    /* Pseudo next, fixed in last_stage */
    L2T_IP6_NEXT_OUTPUT = L2T_IP6_N_NEXT,
} l2t_ip6_next_t;

vlib_node_registration_t l2t_ip6_node;

#define NSTAGES 3

static inline void stage0 (vlib_main_t * vm,
                           vlib_node_runtime_t * node,
                           u32 buffer_index)
{
    vlib_buffer_t *b = vlib_get_buffer (vm, buffer_index);
    vlib_prefetch_buffer_header (b, STORE);
    /* l2tpv3 header is a long way away, need 2 cache lines */
    CLIB_PREFETCH (b->data, 2*CLIB_CACHE_LINE_BYTES, STORE);
}

static inline void stage1 (vlib_main_t * vm,
                           vlib_node_runtime_t * node,
                           u32 bi)
{
    vlib_buffer_t *b = vlib_get_buffer (vm, bi);
    l2t_main_t *lm = &l2t_main;
    ip6_header_t * ip6 = vlib_buffer_get_current (b);
    u32 session_index;
    uword *p;
    l2tpv3_header_t * l2t;

    /* Not L2tpv3 (0x73, 0t115)? Use the normal path. */
    if (PREDICT_FALSE(ip6->protocol != 0x73)) {
        vnet_buffer(b)->l2t.next_index = L2T_IP6_NEXT_IP6_INPUT;
        return;
    }

    /* Make up your minds, people... */
    switch (lm->lookup_type) {
    case L2T_LOOKUP_SRC_ADDRESS:
        p = hash_get_mem (lm->session_by_src_address, &ip6->src_address);
        break;
    case L2T_LOOKUP_DST_ADDRESS:
        p = hash_get_mem (lm->session_by_dst_address, &ip6->dst_address);
        break;
    case L2T_LOOKUP_SESSION_ID:
        l2t = (l2tpv3_header_t*)(ip6+1);
        p = hash_get (lm->session_by_session_id, l2t->session_id);
        break;
    default:
        ASSERT(0);
    }

    if (PREDICT_FALSE(p == 0)) {
        vnet_buffer(b)->l2t.next_index = L2T_IP6_NEXT_IP6_INPUT;
        return;
    } else {
        session_index = p[0];
    }

    /* Remember mapping index, prefetch the mini counter */
    vnet_buffer(b)->l2t.next_index = L2T_IP6_NEXT_OUTPUT;
    vnet_buffer(b)->l2t.session_index = session_index;

    /* Each mapping has 2 x (pkt, byte) counters, hence the shift */
    CLIB_PREFETCH(lm->counter_main.mini + (p[0]<<1), CLIB_CACHE_LINE_BYTES,
                  STORE);
}

static inline u32 last_stage (vlib_main_t *vm, vlib_node_runtime_t *node,
                              u32 bi)
{
    vlib_buffer_t *b = vlib_get_buffer (vm, bi);
    l2t_main_t *lm = &l2t_main;
    ip6_header_t * ip6 = vlib_buffer_get_current (b);
    vlib_node_t *n = vlib_get_node (vm, l2t_ip6_node.index);
    u32 node_counter_base_index = n->error_heap_index;
    vlib_error_main_t * em = &vm->error_main;
    ethernet_header_t * l2_payload;
    l2tpv3_header_t * l2t;      /* original l2 header */
    ethernet_vlan_header_t * vh; /* synthesized 802.1q vlan header */
    u32 counter_index;
    l2t_session_t * session;
    u16 payload_ethertype;
    u8 dst_mac_address[6];
    u8 src_mac_address[6];
    u8 *vlan_header_pos;
    
    /* Other-than-output pkt? We're done... */
    if (vnet_buffer(b)->l2t.next_index != L2T_IP6_NEXT_OUTPUT) 
        return vnet_buffer(b)->l2t.next_index;

    em->counters[node_counter_base_index + L2T_IP6_ERROR_USER_TO_NETWORK] += 1;
    
    counter_index = 
        session_index_to_counter_index (vnet_buffer(b)->l2t.session_index,
                                        SESSION_COUNTER_USER_TO_NETWORK);

    /* per-mapping byte stats include the ethernet header */
    vlib_increment_combined_counter (&lm->counter_main, counter_index,
                                     1 /* packet_increment */,
                                     vlib_buffer_length_in_chain (vm, b) +
                                     sizeof (ethernet_header_t));
    
    session = pool_elt_at_index (lm->sessions, 
                                 vnet_buffer(b)->l2t.session_index);

    /* build the 802.1q encaps. Advance past ip6 and l2tpv3 hds */
    vlib_buffer_advance (b, sizeof (*ip6));
    l2t = vlib_buffer_get_current (b);
    
    /* $$$ wonder if we really need these checks... */
    if (PREDICT_FALSE(l2t->session_id != session->local_session_id)) {
          b->error = lm->ip6_error_node->
              errors[L2T_IP6_ERROR_SESSION_ID_MISMATCH];
          return L2T_IP6_NEXT_DROP;
    }

    if (PREDICT_FALSE(!((l2t->cookie == session->local_cookie) || 
                        ((session->cookie_flags & L2TP_COOKIE_ROLLOVER_LOCAL) &&
                         (l2t->cookie == session->lcl_ro_cookie))))) {
          b->error = lm->ip6_error_node->
              errors[L2T_IP6_ERROR_COOKIE_MISMATCH];
          return L2T_IP6_NEXT_DROP;
    }

    vnet_buffer(b)->sw_if_index[VLIB_TX] = session->l2_output_sw_if_index;

    vlib_buffer_advance (b, sizeof (*l2t));

    /* point at currrent l2 hdr */
    l2_payload = vlib_buffer_get_current (b);

    /* $$$$ rework for speed */

    /* Save type */
    payload_ethertype = l2_payload->type;

    /* Save src/dst MAC addresses */
#define _(i)  dst_mac_address[i] = l2_payload->dst_address[i];
    _(0) _(1) _(2) _(3) _(4) _(5);
#undef _
#define _(i)  src_mac_address[i] = l2_payload->src_address[i];
    _(0) _(1) _(2) _(3) _(4) _(5);
#undef _

    /* Punch in space for 802.1q tag */
    vlib_buffer_advance (b, -4);
    l2_payload = vlib_buffer_get_current (b);

    /* Restore MAC addresses */
#define _(i)  l2_payload->dst_address[i] = dst_mac_address[i];
    _(0) _(1) _(2) _(3) _(4) _(5);
#undef _
#define _(i)  l2_payload->src_address[i] = src_mac_address[i];
    _(0) _(1) _(2) _(3) _(4) _(5);
#undef _
    /* Set (outer) ethertype to 802.1q vlan */
    l2_payload->type = clib_host_to_net_u16 (0x8100);
    vlan_header_pos = (u8 *)(l2_payload+1);
#if 0
    vlan_header_pos = session->l2_sublayer_present ? 
        vlan_header_pos : vlan_header_pos - 4;
#endif
    vh = (ethernet_vlan_header_t *)vlan_header_pos;
    vh->priority_cfi_and_id = session->vlan_id;
    vh->type = payload_ethertype;

    if (PREDICT_FALSE(b->flags & VLIB_BUFFER_IS_TRACED)) {
        l2t_trace_t *t = vlib_add_trace (vm, node, b, sizeof (*t));
        t->is_user_to_network = 1;
        t->our_address.as_u64[0] = 
            ip6->dst_address.as_u64[0];
        t->our_address.as_u64[1] = 
            ip6->dst_address.as_u64[1];
        t->client_address.as_u64[0] = 
            ip6->src_address.as_u64[0];
        t->client_address.as_u64[1] = 
            ip6->src_address.as_u64[1];
        t->session_index = vnet_buffer(b)->l2t.session_index;
        t->vlan_id_host_byte_order = clib_net_to_host_u16 (session->vlan_id);
    }

    return session->l2_output_next_index;
}

#include <vnet/pipeline.h>

static uword ip6_l2t_node_fn (vlib_main_t * vm,
                              vlib_node_runtime_t * node,
                              vlib_frame_t * frame)
{
    l2t_main_t *lm = &l2t_main;
    lm->ip6_error_node = vlib_node_get_runtime (vm, l2t_ip6_node.index);

    return dispatch_pipeline (vm, node, frame);
}

static VLIB_REGISTER_NODE (sw6_ip6_node) = {
  .function = ip6_l2t_node_fn,
  .name = "ip6-l2t-input",
  .vector_size = sizeof (u32),
  .format_trace = format_l2t_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  
  .n_errors = ARRAY_LEN(l2t_ip6_error_strings),
  .error_strings = l2t_ip6_error_strings,

  .n_next_nodes = L2T_IP6_N_NEXT,

  /* edit / add dispositions here */
  .next_nodes = {
        [L2T_IP6_NEXT_IP6_INPUT] = "ip6-input",
        [L2T_IP6_NEXT_DROP] = "error-drop",
  },
};

static clib_error_t *
l2tp_config (vlib_main_t * vm, unformat_input_t * input)
{
    l2t_main_t *lm = &l2t_main;
    
    while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT) {
        if (unformat (input, "lookup-v6-src"))
            lm->lookup_type = L2T_LOOKUP_SRC_ADDRESS;
        else if (unformat (input, "lookup-v6-dst"))
            lm->lookup_type = L2T_LOOKUP_DST_ADDRESS;
        else if (unformat (input, "lookup-session-id"))
            lm->lookup_type = L2T_LOOKUP_SESSION_ID;
        else return clib_error_return (0, "unknown input `%U'",
                                       format_unformat_error, input);
    }
    return 0;
}

VLIB_CONFIG_FUNCTION (l2tp_config, "l2tp");

clib_error_t *
l2t_ip6_init (vlib_main_t *vm)
{
    l2t_main_t *lm = &l2t_main;

    lm->vnet_main = vnet_get_main();
    lm->vlib_main = vm;
    lm->lookup_type = L2T_LOOKUP_DST_ADDRESS;

    lm->session_by_src_address = hash_create_mem 
        (0, sizeof (ip6_address_t) /* key bytes */,
         sizeof (u32) /* value bytes */);
    lm->session_by_dst_address = hash_create_mem 
        (0, sizeof (ip6_address_t) /* key bytes */,
         sizeof (u32) /* value bytes */);
    lm->session_by_session_id = hash_create (0, sizeof (uword));

    lm->session_by_vlan_and_rx_sw_if_index = hash_create (0, sizeof (uword));
    
#if DPDK == 0
    vice_set_next_node (VICE_RX_NEXT_IP6_INPUT, "ip6-l2t-input");
    ixgev_set_next_node (IXGEV_RX_NEXT_IP6_INPUT, "ip6-l2t-input");
    ixge_set_next_node (IXGE_RX_NEXT_IP6_INPUT, "ip6-l2t-input");
    ige_set_next_node (IGE_RX_NEXT_IP6_INPUT, "ip6-l2t-input");
#else
    dpdk_set_next_node (DPDK_RX_NEXT_IP6_INPUT, "ip6-l2t-input");
#endif
    return 0;
}

VLIB_INIT_FUNCTION (l2t_ip6_init);