include/linux/if_arp.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   4  *              operating system.  INET is implemented using the  BSD Socket
   5  *              interface as the means of communication with the user level.
   6  *
   7  *              Global definitions for the ARP (RFC 826) protocol.
   8  *
   9  * Version:     @(#)if_arp.h    1.0.1   04/16/93
  10  *
  11  * Authors:     Original taken from Berkeley UNIX 4.3, (c) UCB 1986-1988
  12  *              Portions taken from the KA9Q/NOS (v2.00m PA0GRI) source.
  13  *              Ross Biro
  14  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  15  *              Florian La Roche,
  16  *              Jonathan Layes <layes@loran.com>
  17  *              Arnaldo Carvalho de Melo <acme@conectiva.com.br> ARPHRD_HWX25
  18  */
  19 #ifndef _LINUX_IF_ARP_H
  20 #define _LINUX_IF_ARP_H
  21
  22 #include <linux/skbuff.h>
  23 #include <uapi/linux/if_arp.h>
  24
  25 static inline struct arphdr *arp_hdr(const struct sk_buff *skb)
  26 {
  27         return (struct arphdr *)skb_network_header(skb);
  28 }
  29
  30 static inline unsigned int arp_hdr_len(const struct net_device *dev)
  31 {
  32         switch (dev->type) {
  33 #if IS_ENABLED(CONFIG_FIREWIRE_NET)
  34         case ARPHRD_IEEE1394:
  35                 /* ARP header, device address and 2 IP addresses */
  36                 return sizeof(struct arphdr) + dev->addr_len + sizeof(u32) * 2;
  37 #endif
  38         default:
  39                 /* ARP header, plus 2 device addresses, plus 2 IP addresses. */
  40                 return sizeof(struct arphdr) + (dev->addr_len + sizeof(u32)) * 2;
  41         }
  42 }
  43
  44 static inline bool dev_is_mac_header_xmit(const struct net_device *dev)
  45 {
  46         switch (dev->type) {
  47         case ARPHRD_TUNNEL:
  48         case ARPHRD_TUNNEL6:
  49         case ARPHRD_SIT:
  50         case ARPHRD_IPGRE:
  51         case ARPHRD_IP6GRE:
  52         case ARPHRD_VOID:
  53         case ARPHRD_NONE:
  54         case ARPHRD_RAWIP:
  55         case ARPHRD_PIMREG:
  56         /* PPP adds its l2 header automatically in ppp_start_xmit().
  57          * This makes it look like an l3 device to __bpf_redirect() and tcf_mirred_init().
  58          */
  59         case ARPHRD_PPP:
  60                 return false;
  61         default:
  62                 return true;
  63         }
  64 }
  65
  66 #endif  /* _LINUX_IF_ARP_H */