/* * ethernet/arp.c: IP v4 ARP node * * Copyright (c) 2010 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 __ARP_PACKET_H__ #define __ARP_PACKET_H__ #include <vnet/arp/arp.h> /* Either we drop the packet or we send a reply to the sender. */ typedef enum { ARP_REPLY_NEXT_DROP, ARP_REPLY_NEXT_REPLY_TX, ARP_REPLY_N_NEXT, } arp_reply_next_t; static_always_inline u32 arp_mk_reply (vnet_main_t * vnm, vlib_buffer_t * p0, u32 sw_if_index0, const ip4_address_t * if_addr0, ethernet_arp_header_t * arp0, ethernet_header_t * eth_rx) { vnet_hw_interface_t *hw_if0; u8 *rewrite0, rewrite0_len; ethernet_header_t *eth_tx; u32 next0; /* Send a reply. An adjacency to the sender is not always present, so we use the interface to build us a rewrite string which will contain all the necessary tags. */ rewrite0 = ethernet_build_rewrite (vnm, sw_if_index0, VNET_LINK_ARP, eth_rx->src_address); rewrite0_len = vec_len (rewrite0); /* Figure out how much to rewind current data from adjacency. */ vlib_buffer_advance (p0, -rewrite0_len); eth_tx = vlib_buffer_get_current (p0); vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0; hw_if0 = vnet_get_sup_hw_interface (vnm, sw_if_index0); /* Send reply back through input interface */ vnet_buffer (p0)->sw_if_index[VLIB_TX] = sw_if_index0; next0 = ARP_REPLY_NEXT_REPLY_TX; arp0->opcode = clib_host_to_net_u16 (ETHERNET_ARP_OPCODE_reply); arp0->ip4_over_ethernet[1] = arp0->ip4_over_ethernet[0]; mac_address_from_bytes (&arp0->ip4_over_ethernet[0].mac, hw_if0->hw_address); clib_mem_unaligned (&arp0->ip4_over_ethernet[0].ip4.data_u32, u32) = if_addr0->data_u32; /* Hardware must be ethernet-like. */ ASSERT (vec_len (hw_if0->hw_address) == 6); /* the rx nd tx ethernet headers wil overlap in the case * when we received a tagged VLAN=0 packet, but we are sending * back untagged */ clib_memcpy_fast (eth_tx, rewrite0, vec_len (rewrite0)); vec_free (rewrite0); return (next0); } #endif /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */