| Neale Ranns | cbe25aa | 2019-09-30 10:53:31 +0000 | [diff] [blame] | 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 | 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 | rewrite0 = ethernet_build_rewrite (vnm, sw_if_index0, |
| 48 | VNET_LINK_ARP, eth_rx->src_address); |
| 49 | rewrite0_len = vec_len (rewrite0); |
| 50 | |
| 51 | /* Figure out how much to rewind current data from adjacency. */ |
| 52 | vlib_buffer_advance (p0, -rewrite0_len); |
| 53 | eth_tx = vlib_buffer_get_current (p0); |
| 54 | |
| 55 | vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0; |
| 56 | hw_if0 = vnet_get_sup_hw_interface (vnm, sw_if_index0); |
| 57 | |
| 58 | /* Send reply back through input interface */ |
| 59 | vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0; |
| 60 | next0 = ARP_REPLY_NEXT_REPLY_TX; |
| 61 | |
| 62 | arp0->opcode = clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply); |
| 63 | |
| 64 | arp0->ip4_over_ethernet[1] = arp0->ip4_over_ethernet[0]; |
| 65 | |
| 66 | mac_address_from_bytes (&arp0->ip4_over_ethernet[0].mac, |
| 67 | hw_if0->hw_address); |
| 68 | clib_mem_unaligned (&arp0->ip4_over_ethernet[0].ip4.data_u32, u32) = |
| 69 | if_addr0->data_u32; |
| 70 | |
| 71 | /* Hardware must be ethernet-like. */ |
| 72 | ASSERT (vec_len (hw_if0->hw_address) == 6); |
| 73 | |
| 74 | /* the rx nd tx ethernet headers wil overlap in the case |
| 75 | * when we received a tagged VLAN=0 packet, but we are sending |
| 76 | * back untagged */ |
| 77 | clib_memcpy_fast (eth_tx, rewrite0, vec_len (rewrite0)); |
| 78 | vec_free (rewrite0); |
| 79 | |
| 80 | return (next0); |
| 81 | } |
| 82 | |
| 83 | #endif |
| 84 | |
| 85 | /* |
| 86 | * fd.io coding-style-patch-verification: ON |
| 87 | * |
| 88 | * Local Variables: |
| 89 | * eval: (c-set-style "gnu") |
| 90 | * End: |
| 91 | */ |