Line data    Source code

       1             : /*
       2             :  * ethernet/arp.c: IP v4 ARP node
       3             :  *
       4             :  * Copyright (c) 2010 Cisco and/or its affiliates.
       5             :  * Licensed under the Apache License, Version 2.0 (the "License");
       6             :  * you may not use this file except in compliance with the License.
       7             :  * You may obtain a copy of the License at:
       8             :  *
       9             :  *     http://www.apache.org/licenses/LICENSE-2.0
      10             :  *
      11             :  * Unless required by applicable law or agreed to in writing, software
      12             :  * distributed under the License is distributed on an "AS IS" BASIS,
      13             :  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      14             :  * See the License for the specific language governing permissions and
      15             :  * limitations under the License.
      16             :  */
      17             : 
      18             : #ifndef __ARP_PACKET_H__
      19             : #define __ARP_PACKET_H__
      20             : 
      21             : #include <vnet/arp/arp.h>
      22             : 
      23             : /* Either we drop the packet or we send a reply to the sender. */
      24             : typedef enum
      25             : {
      26             :   ARP_REPLY_NEXT_DROP,
      27             :   ARP_REPLY_NEXT_REPLY_TX,
      28             :   ARP_REPLY_N_NEXT,
      29             : } arp_reply_next_t;
      30             : 
      31             : static_always_inline u32
      32        1974 : arp_mk_reply (vnet_main_t * vnm,
      33             :               vlib_buffer_t * p0,
      34             :               u32 sw_if_index0,
      35             :               const ip4_address_t * if_addr0,
      36             :               ethernet_arp_header_t * arp0, ethernet_header_t * eth_rx)
      37             : {
      38             :   vnet_hw_interface_t *hw_if0;
      39             :   u8 *rewrite0, rewrite0_len;
      40             :   ethernet_header_t *eth_tx;
      41             :   u32 next0;
      42             : 
      43             :   /* Send a reply.
      44             :      An adjacency to the sender is not always present,
      45             :      so we use the interface to build us a rewrite string
      46             :      which will contain all the necessary tags. */
      47        3948 :   rewrite0 = ethernet_build_rewrite (vnm, sw_if_index0,
      48        1974 :                                      VNET_LINK_ARP, eth_rx->src_address);
      49        1974 :   rewrite0_len = vec_len (rewrite0);
      50             : 
      51             :   /* Figure out how much to rewind current data from adjacency. */
      52        1974 :   vlib_buffer_advance (p0, -rewrite0_len);
      53        1974 :   eth_tx = vlib_buffer_get_current (p0);
      54             : 
      55        1974 :   vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
      56        1974 :   hw_if0 = vnet_get_sup_hw_interface (vnm, sw_if_index0);
      57             : 
      58             :   /* Send reply back through input interface */
      59        1974 :   vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0;
      60        1974 :   next0 = ARP_REPLY_NEXT_REPLY_TX;
      61             : 
      62        1974 :   arp0->opcode = clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply);
      63             : 
      64        1974 :   arp0->ip4_over_ethernet[1] = arp0->ip4_over_ethernet[0];
      65             : 
      66        1974 :   mac_address_from_bytes (&arp0->ip4_over_ethernet[0].mac,
      67        1974 :                           hw_if0->hw_address);
      68        1974 :   clib_mem_unaligned (&arp0->ip4_over_ethernet[0].ip4.data_u32, u32) =
      69        1974 :     if_addr0->data_u32;
      70             : 
      71        1974 :   p0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
      72             : 
      73             :   /* Hardware must be ethernet-like. */
      74        1974 :   ASSERT (vec_len (hw_if0->hw_address) == 6);
      75             : 
      76             :   /* the rx nd tx ethernet headers wil overlap in the case
      77             :    * when we received a tagged VLAN=0 packet, but we are sending
      78             :    * back untagged */
      79        1974 :   clib_memcpy_fast (eth_tx, rewrite0, vec_len (rewrite0));
      80        1974 :   vec_free (rewrite0);
      81             : 
      82        1974 :   return (next0);
      83             : }
      84             : 
      85             : #endif
      86             : 
      87             : /*
      88             :  * fd.io coding-style-patch-verification: ON
      89             :  *
      90             :  * Local Variables:
      91             :  * eval: (c-set-style "gnu")
      92             :  * End:
      93             :  */