| /**************************************************************************** |
| * net/arp/arp_out.c |
| * |
| * Copyright (C) 2007-2011, 2014-2015, 2017-2018 Gregory Nutt. All rights |
| * reserved. |
| * Author: Gregory Nutt <gnutt@nuttx.org> |
| * |
| * Based on uIP which also has a BSD style license: |
| * |
| * Author: Adam Dunkels <adam@dunkels.com> |
| * Copyright (c) 2001-2003, Adam Dunkels. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. The name of the author may not be used to endorse or promote |
| * products derived from this software without specific prior |
| * written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS |
| * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
| * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE |
| * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Included Files |
| ****************************************************************************/ |
| |
| #include <nuttx/config.h> |
| |
| #include <string.h> |
| #include <debug.h> |
| |
| #include <nuttx/net/net.h> |
| #include <nuttx/net/netdev.h> |
| |
| #include "route/route.h" |
| #include "arp/arp.h" |
| |
| #ifdef CONFIG_NET_ARP |
| |
| /**************************************************************************** |
| * Private Data |
| ****************************************************************************/ |
| |
| /* Support for broadcast address */ |
| |
| static const struct ether_addr g_broadcast_ethaddr = |
| { |
| { |
| 0xff, 0xff, 0xff, 0xff, 0xff, 0xff |
| } |
| }; |
| |
| static const uint16_t g_broadcast_ipaddr[2] = |
| { |
| 0xffff, 0xffff |
| }; |
| |
| /* Support for IGMP multicast addresses. |
| * |
| * Well-known ethernet multicast address: |
| * |
| * ADDRESS TYPE USAGE |
| * 01-00-0c-cc-cc-cc 0x0802 CDP (Cisco Discovery Protocol), |
| * VTP (Virtual Trunking Protocol) |
| * 01-00-0c-cc-cc-cd 0x0802 Cisco Shared Spanning Tree Protocol Address |
| * 01-80-c2-00-00-00 0x0802 Spanning Tree Protocol (for bridges) IEEE 802.1D |
| * 01-80-c2-00-00-02 0x0809 Ethernet OAM Protocol IEEE 802.3ah |
| * 01-00-5e-xx-xx-xx 0x0800 IPv4 IGMP Multicast Address |
| * 33-33-00-00-00-00 0x86DD IPv6 Neighbor Discovery |
| * 33-33-xx-xx-xx-xx 0x86DD IPv6 Multicast Address (RFC3307) |
| * |
| * The following is the first three octects of the IGMP address: |
| */ |
| |
| #ifdef CONFIG_NET_IGMP |
| static const uint8_t g_multicast_ethaddr[3] = |
| { |
| 0x01, 0x00, 0x5e |
| }; |
| #endif |
| |
| /**************************************************************************** |
| * Public Functions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Name: arp_out |
| * |
| * Description: |
| * This function should be called before sending out an IP packet. The |
| * function checks the destination IP address of the IP packet to see |
| * what Ethernet MAC address that should be used as a destination MAC |
| * address on the Ethernet. |
| * |
| * If the destination IP address is in the local network (determined |
| * by logical ANDing of netmask and our IP address), the function |
| * checks the ARP cache to see if an entry for the destination IP |
| * address is found. If so, an Ethernet header is pre-pended at the |
| * beginning of the packet and the function returns. |
| * |
| * If no ARP cache entry is found for the destination IP address, the |
| * packet in the d_buf is replaced by an ARP request packet for the |
| * IP address. The IP packet is dropped and it is assumed that the |
| * higher level protocols (e.g., TCP) eventually will retransmit the |
| * dropped packet. |
| * |
| * Upon return in either the case, a packet to be sent is present in the |
| * d_buf buffer and the d_len field holds the length of the Ethernet |
| * frame that should be transmitted. |
| * |
| ****************************************************************************/ |
| |
| void arp_out(FAR struct net_driver_s *dev) |
| { |
| struct ether_addr ethaddr; |
| FAR struct eth_hdr_s *peth = ETHBUF; |
| FAR struct arp_iphdr_s *pip = ARPIPBUF; |
| in_addr_t ipaddr; |
| in_addr_t destipaddr; |
| int ret; |
| |
| /* ARP support is only built if the Ethernet link layer is supported. |
| * Continue and send the ARP request only if this device uses the |
| * Ethernet link layer protocol. |
| */ |
| |
| if (dev->d_lltype != NET_LL_ETHERNET && |
| dev->d_lltype != NET_LL_IEEE80211) |
| { |
| return; |
| } |
| |
| #if defined(CONFIG_NET_PKT) || defined(CONFIG_NET_ARP_SEND) |
| /* Skip sending ARP requests when the frame to be transmitted was |
| * written into a packet socket. |
| */ |
| |
| if (IFF_IS_NOARP(dev->d_flags)) |
| { |
| /* Clear the indication and let the packet continue on its way. */ |
| |
| IFF_CLR_NOARP(dev->d_flags); |
| return; |
| } |
| #endif |
| |
| /* Find the destination IP address in the ARP table and construct |
| * the Ethernet header. If the destination IP address isn't on the |
| * local network, we use the default router's IP address instead. |
| * |
| * If not ARP table entry is found, we overwrite the original IP |
| * packet with an ARP request for the IP address. |
| */ |
| |
| /* First check if destination is a local broadcast. */ |
| |
| if (net_ipv4addr_hdrcmp(pip->eh_destipaddr, g_broadcast_ipaddr)) |
| { |
| memcpy(peth->dest, |
| g_broadcast_ethaddr.ether_addr_octet, |
| ETHER_ADDR_LEN); |
| goto finish_header; |
| } |
| |
| #ifdef CONFIG_NET_IGMP |
| /* Check if the destination address is a multicast address |
| * |
| * - IPv4: |
| * multicast addresses lie in the class D group -- The address range |
| * 224.0.0.0 to 239.255.255.255 (224.0.0.0/4) |
| * |
| * - IPv6 multicast addresses are have the high-order octet of the |
| * addresses=0xff (ff00::/8.) |
| */ |
| |
| if (NTOHS(pip->eh_destipaddr[0]) >= 0xe000 && |
| NTOHS(pip->eh_destipaddr[0]) <= 0xefff) |
| { |
| /* Build the well-known IPv4 IGMP Ethernet address. The first |
| * three bytes are fixed; the final three variable come from the |
| * last three bytes of the IPv4 address (network order). |
| * |
| * Address range : 01:00:5e:00:00:00 to 01:00:5e:7f:ff:ff |
| */ |
| |
| FAR const uint8_t *ip = (FAR uint8_t *)pip->eh_destipaddr; |
| |
| peth->dest[0] = g_multicast_ethaddr[0]; |
| peth->dest[1] = g_multicast_ethaddr[1]; |
| peth->dest[2] = g_multicast_ethaddr[2]; |
| peth->dest[3] = ip[1] & 0x7f; |
| peth->dest[4] = ip[2]; |
| peth->dest[5] = ip[3]; |
| |
| goto finish_header; |
| } |
| #endif |
| |
| /* Check if the destination address is on the local network. */ |
| |
| destipaddr = net_ip4addr_conv32(pip->eh_destipaddr); |
| if (!net_ipv4addr_maskcmp(destipaddr, dev->d_ipaddr, dev->d_netmask)) |
| { |
| /* Destination address is not on the local network */ |
| |
| #ifdef CONFIG_NET_ROUTE |
| /* We have a routing table.. find the correct router to use in |
| * this case (or, as a fall-back, use the device's default router |
| * address). We will use the router IP address instead of the |
| * destination address when determining the MAC address. |
| */ |
| |
| netdev_ipv4_router(dev, destipaddr, &ipaddr); |
| #else |
| /* Use the device's default router IP address instead of the |
| * destination address when determining the MAC address. |
| */ |
| |
| net_ipv4addr_copy(ipaddr, dev->d_draddr); |
| #endif |
| } |
| |
| /* The destination address is on the local network. Check if it is |
| * the sub-net broadcast address. |
| */ |
| |
| else if (net_ipv4addr_broadcast(destipaddr, dev->d_netmask)) |
| { |
| /* Yes.. then we won't need to know the destination MAC address */ |
| |
| memcpy(peth->dest, |
| g_broadcast_ethaddr.ether_addr_octet, |
| ETHER_ADDR_LEN); |
| goto finish_header; |
| } |
| else |
| { |
| /* Else, we use the destination IP address. */ |
| |
| net_ipv4addr_copy(ipaddr, destipaddr); |
| } |
| |
| /* Check if we already have this destination address in the ARP table */ |
| |
| ret = arp_find(ipaddr, ethaddr.ether_addr_octet, dev); |
| if (ret < 0) |
| { |
| ninfo("ARP request for IP %08lx\n", (unsigned long)ipaddr); |
| |
| /* The destination address was not in our ARP table, so we overwrite |
| * the IP packet with an ARP request. |
| */ |
| |
| arp_format(dev, ipaddr); |
| arp_dump(ARPBUF); |
| return; |
| } |
| |
| /* Build an Ethernet header. */ |
| |
| memcpy(peth->dest, ethaddr.ether_addr_octet, ETHER_ADDR_LEN); |
| |
| /* Finish populating the Ethernet header */ |
| |
| finish_header: |
| memcpy(peth->src, dev->d_mac.ether.ether_addr_octet, ETHER_ADDR_LEN); |
| peth->type = HTONS(ETHTYPE_IP); |
| dev->d_len += ETH_HDRLEN; |
| } |
| |
| #endif /* CONFIG_NET_ARP */ |