l2_input.h

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/*
 * l2_input.h : layer 2 input packet processing
 *
 * Copyright (c) 2013 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.
 */

#ifndef included_vnet_l2_input_h
#define included_vnet_l2_input_h

#include <vlib/vlib.h>
#include <vnet/vnet.h>
#include <vnet/l2/l2_bd.h>
#include <vnet/ethernet/packet.h>
#include <vnet/ip/ip.h>

// Per-subinterface L2 feature configuration

typedef struct {

  union {
    u16 bd_index;                 // bridge domain id
    u32 output_sw_if_index;    // for xconnect
  };

  // Interface mode. If both are 0, this interface is in L3 mode
  u8  xconnect;
  u8  bridge;

  // this is the bvi interface for the bridge-domain
  u8  bvi;  

  // config for which input features are configured on this interface
  u32 feature_bitmap;

  // some of these flags are also in the feature bitmap
  u8  learn_enable;  
  u8  fwd_enable;    
  u8  flood_enable;

  // split horizon group
  u8  shg;

} l2_input_config_t;


typedef struct {

  // Next nodes for the feature bitmap
  u32 feat_next_node_index[32];

  /* config vector indexed by sw_if_index */
  l2_input_config_t *configs;

  /* bridge domain config vector indexed by BD ID */
  l2_bridge_domain_t *bd_configs;

  /* convenience variables */
  vlib_main_t * vlib_main;
  vnet_main_t * vnet_main;
} l2input_main_t;

extern l2input_main_t l2input_main;

extern vlib_node_registration_t l2input_node;

static_always_inline l2_bridge_domain_t * 
l2input_bd_config_from_index (l2input_main_t * l2im, u32 bd_index)
{
    l2_bridge_domain_t * bd_config;

    bd_config = vec_elt_at_index (l2im->bd_configs, bd_index);
    return bd_is_valid (bd_config) ? bd_config : NULL;
}

// L2 input features

// Mappings from feature ID to graph node name
#define foreach_l2input_feat \
 _(DROP,          "feature-bitmap-drop")        \
 _(CLASSIFY,      "l2-classify")                \
 _(XCONNECT,      "l2-output")                  \
 _(IPIW,          "feature-bitmap-drop")        \
 _(FLOOD,         "l2-flood")                   \
 _(ARP_TERM,      "arp-term-l2bd")              \
 _(UU_FLOOD,      "l2-flood")                   \
 _(FWD,           "l2-fwd")                     \
 _(RW,            "l2-rw")                      \
 _(LEARN,         "l2-learn")                   \
 _(VTR,           "l2-input-vtr")               \
 _(VPATH,         "vpath-input-l2")             \
 _(CTRL_PKT,      "feature-bitmap-drop")        \
 _(L2PT,          "feature-bitmap-drop")        \
 _(IGMP_SNOOP,    "feature-bitmap-drop")        \
 _(MLD_SNOOP,     "feature-bitmap-drop")        \
 _(DHCP_SNOOP,    "feature-bitmap-drop")        \
 _(DAI,           "feature-bitmap-drop")        \
 _(IPSG,          "feature-bitmap-drop")        \
 _(ACL,           "l2-input-acl")               \
 _(QOS,           "feature-bitmap-drop")        \
 _(CFM,           "feature-bitmap-drop")        \
 _(SPAN,          "feature-bitmap-drop")

// Feature bitmap positions
typedef enum {
#define _(sym,str) L2INPUT_FEAT_##sym##_BIT,
  foreach_l2input_feat
#undef _
  L2INPUT_N_FEAT,
} l2input_feat_t;

// Feature bit masks
typedef enum {
#define _(sym,str) L2INPUT_FEAT_##sym = (1<<L2INPUT_FEAT_##sym##_BIT),
  foreach_l2input_feat
#undef _
} l2input_feat_masks_t;
           
// Return an array of strings containing graph node names of each feature
char **l2input_get_feat_names(void);


static_always_inline u8 bd_feature_flood (l2_bridge_domain_t * bd_config)
{
    return ((bd_config->feature_bitmap & L2INPUT_FEAT_FLOOD) ==
            L2INPUT_FEAT_FLOOD);
}

static_always_inline u8 bd_feature_uu_flood (l2_bridge_domain_t * bd_config)
{
    return ((bd_config->feature_bitmap & L2INPUT_FEAT_UU_FLOOD) ==
            L2INPUT_FEAT_UU_FLOOD);
}

static_always_inline u8 bd_feature_forward (l2_bridge_domain_t * bd_config)
{
    return ((bd_config->feature_bitmap & L2INPUT_FEAT_FWD) ==
            L2INPUT_FEAT_FWD);
}

static_always_inline u8 bd_feature_learn (l2_bridge_domain_t * bd_config)
{
    return ((bd_config->feature_bitmap & L2INPUT_FEAT_LEARN) ==
            L2INPUT_FEAT_LEARN);
}

static_always_inline u8 bd_feature_arp_term (l2_bridge_domain_t * bd_config)
{
    return ((bd_config->feature_bitmap & L2INPUT_FEAT_ARP_TERM) ==
            L2INPUT_FEAT_ARP_TERM);
}

// Masks for eliminating features that do not apply to a packet

#define IP4_FEAT_MASK  ~(L2INPUT_FEAT_CTRL_PKT    | \
                         L2INPUT_FEAT_MLD_SNOOP   | \
                         L2INPUT_FEAT_L2PT        | \
                         L2INPUT_FEAT_CFM         | \
                         L2INPUT_FEAT_DAI)

#define IP6_FEAT_MASK  ~(L2INPUT_FEAT_CTRL_PKT    | \
                         L2INPUT_FEAT_IGMP_SNOOP  | \
                         L2INPUT_FEAT_L2PT        | \
                         L2INPUT_FEAT_CFM         | \
                         L2INPUT_FEAT_DAI)

#define IP_UDP_TCP_FEAT_MASK  ~(L2INPUT_FEAT_CTRL_PKT   | \
                                L2INPUT_FEAT_L2PT       | \
                                L2INPUT_FEAT_IGMP_SNOOP | \
                                L2INPUT_FEAT_MLD_SNOOP  | \
                                L2INPUT_FEAT_DHCP_SNOOP | \
                                L2INPUT_FEAT_CFM        | \
                                L2INPUT_FEAT_DAI)

#define MPLS_FEAT_MASK  ~(L2INPUT_FEAT_CTRL_PKT   | \
                          L2INPUT_FEAT_L2PT       | \
                          L2INPUT_FEAT_IGMP_SNOOP | \
                          L2INPUT_FEAT_MLD_SNOOP  | \
                          L2INPUT_FEAT_DHCP_SNOOP | \
                          L2INPUT_FEAT_CFM        | \
                          L2INPUT_FEAT_DAI)


// Get a pointer to the config for the given interface
l2_input_config_t * l2input_intf_config (u32 sw_if_index);

// Enable (or disable) the feature in the bitmap for the given interface
u32 l2input_intf_bitmap_enable (u32 sw_if_index,
                                 u32 feature_bitmap,
                                 u32 enable);

//Sets modifies flags from a bridge domain
u32 l2input_set_bridge_features(u32 bd_index,
                                u32 feat_mask,
                                u32 feat_value);


#define MODE_L3        0
#define MODE_L2_BRIDGE 1
#define MODE_L2_XC     2
#define MODE_L2_CLASSIFY 3

#define MODE_ERROR_ETH        1
#define MODE_ERROR_BVI_DEF    2

u32 set_int_l2_mode (vlib_main_t * vm,
                     vnet_main_t * vnet_main,
                     u32 mode,
                     u32 sw_if_index,
                     u32 bd_index,
                     u32 bvi,  
                     u32 shg,   
                     u32 xc_sw_if_index);

static inline void
vnet_update_l2_len (vlib_buffer_t * b)
{
  ethernet_header_t * eth;
  u16 ethertype;
  u8 vlan_count = 0;

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

  /* 
   * l2-output pays no attention to this
   * but the tag push/pop code on an l2 subif needs it.
   * 
   * Determine l2 header len, check for up to 2 vlans 
   */
  vnet_buffer(b)->l2.l2_len = sizeof(ethernet_header_t);
  ethertype = clib_net_to_host_u16(eth->type);
  if ((ethertype == ETHERNET_TYPE_VLAN) ||
      (ethertype == ETHERNET_TYPE_DOT1AD) ||
      (ethertype == ETHERNET_TYPE_VLAN_9100) ||
      (ethertype == ETHERNET_TYPE_VLAN_9200)) {    
    ethernet_vlan_header_t * vlan;
    vnet_buffer(b)->l2.l2_len += sizeof (*vlan);
    vlan_count = 1;
    vlan = (void *) (eth+1);
    ethertype = clib_net_to_host_u16 (vlan->type);
    if (ethertype == ETHERNET_TYPE_VLAN) {
      vnet_buffer(b)->l2.l2_len += sizeof (*vlan);
      vlan_count = 2;
    }
  }
  ethernet_buffer_set_vlan_count(b, vlan_count);
}

/*
 * Compute flow hash of an ethernet packet, use 5-tuple hash if L3 packet 
 * is ip4 or ip6. Otherwise hash on smac/dmac/etype. 
 * The vlib buffer current pointer is expected to be at ethernet header 
 * and vnet l2.l2_len is exppected to be setup already.
 */
static inline u32 vnet_l2_compute_flow_hash (vlib_buffer_t *b) 
{
  ethernet_header_t * eh = vlib_buffer_get_current(b);
  u8 * l3h = (u8 *)eh + vnet_buffer(b)->l2.l2_len;
  u16 ethertype = clib_net_to_host_u16(*(u16 *)(l3h - 2));

  if (ethertype == ETHERNET_TYPE_IP4) 
    return ip4_compute_flow_hash((ip4_header_t *) l3h, IP_FLOW_HASH_DEFAULT);
  else if (ethertype == ETHERNET_TYPE_IP6) 
    return ip6_compute_flow_hash((ip6_header_t *) l3h, IP_FLOW_HASH_DEFAULT);
  else
    {
      u32 a, b, c;
      u32 * ap = (u32 *) &eh->dst_address[2];
      u32 * bp = (u32 *) &eh->src_address[2];
      a = * ap;
      b = * bp;
      c = ethertype;
      hash_v3_mix32 (a, b, c);
      hash_v3_finalize32 (a, b, c);
      return c;
    }
}

#endif