src/proto_arp.c

   1 /*
   2  * netsniff-ng - the packet sniffing beast
   3  * By Daniel Borkmann <daniel@netsniff-ng.org>
   4  * Copyright 2009, 2010 Daniel Borkmann.
   5  * Subject to the GPL, version 2.
   6  */
   7
   8 #include <stdint.h>
   9 #include <stdint.h>
  10 #include <netinet/in.h>    /* for ntohs() */
  11
  12 #include "proto.h"
  13 #include "protos.h"
  14 #include "dissector_eth.h"
  15 #include "pkt_buff.h"
  16 #include "built_in.h"
  17
  18 struct arphdr {
  19         uint16_t ar_hrd;   /* format of hardware address */
  20         uint16_t ar_pro;   /* format of protocol address */
  21         uint8_t ar_hln;    /* length of hardware address */
  22         uint8_t ar_pln;    /* length of protocol address */
  23         uint16_t ar_op;    /* ARP opcode (command)       */
  24         uint8_t ar_sha[6]; /* sender hardware address    */
  25         uint8_t ar_sip[4]; /* sender IP address          */
  26         uint8_t ar_tha[6]; /* target hardware address    */
  27         uint8_t ar_tip[4]; /* target IP address          */
  28 } __packed;
  29
  30 #define ARPOP_REQUEST   1  /* ARP request                */
  31 #define ARPOP_REPLY     2  /* ARP reply                  */
  32 #define ARPOP_RREQUEST  3  /* RARP request               */
  33 #define ARPOP_RREPLY    4  /* RARP reply                 */
  34 #define ARPOP_InREQUEST 8  /* InARP request              */
  35 #define ARPOP_InREPLY   9  /* InARP reply                */
  36 #define ARPOP_NAK       10 /* (ATM)ARP NAK               */
  37
  38 static void arp(struct pkt_buff *pkt)
  39 {
  40         char *opcode = NULL;
  41         struct arphdr *arp = (struct arphdr *) pkt_pull(pkt, sizeof(*arp));
  42
  43         if (arp == NULL)
  44                 return;
  45
  46         switch (ntohs(arp->ar_op)) {
  47         case ARPOP_REQUEST:
  48                 opcode = "ARP request";
  49                 break;
  50         case ARPOP_REPLY:
  51                 opcode = "ARP reply";
  52                 break;
  53         case ARPOP_RREQUEST:
  54                 opcode = "RARP request";
  55                 break;
  56         case ARPOP_RREPLY:
  57                 opcode = "RARP reply";
  58                 break;
  59         case ARPOP_InREQUEST:
  60                 opcode = "InARP request";
  61                 break;
  62         case ARPOP_InREPLY:
  63                 opcode = "InARP reply";
  64                 break;
  65         case ARPOP_NAK:
  66                 opcode = "(ATM) ARP NAK";
  67                 break;
  68         default:
  69                 opcode = "Unknown";
  70                 break;
  71         };
  72
  73         tprintf(" [ ARP ");
  74         tprintf("Format HA (%u), ", ntohs(arp->ar_hrd));
  75         tprintf("Format Proto (%u), ", ntohs(arp->ar_pro));
  76         tprintf("HA Len (%u), ", ntohs(arp->ar_hln));
  77         tprintf("Proto Len (%u), ", ntohs(arp->ar_pln));
  78         tprintf("Opcode (%u => %s)", ntohs(arp->ar_op), opcode);
  79         tprintf(" ]\n");
  80 }
  81
  82 static void arp_less(struct pkt_buff *pkt)
  83 {
  84         char *opcode = NULL;
  85         struct arphdr *arp = (struct arphdr *) pkt_pull(pkt, sizeof(*arp));
  86
  87         if (arp == NULL)
  88                 return;
  89
  90         switch (ntohs(arp->ar_op)) {
  91         case ARPOP_REQUEST:
  92                 opcode = "ARP request";
  93                 break;
  94         case ARPOP_REPLY:
  95                 opcode = "ARP reply";
  96                 break;
  97         case ARPOP_RREQUEST:
  98                 opcode = "RARP request";
  99                 break;
 100         case ARPOP_RREPLY:
 101                 opcode = "RARP reply";
 102                 break;
 103         case ARPOP_InREQUEST:
 104                 opcode = "InARP request";
 105                 break;
 106         case ARPOP_InREPLY:
 107                 opcode = "InARP reply";
 108                 break;
 109         case ARPOP_NAK:
 110                 opcode = "(ATM) ARP NAK";
 111                 break;
 112         default:
 113                 opcode = "Unknown";
 114                 break;
 115         };
 116
 117         tprintf(" Op %s", opcode);
 118 }
 119
 120 struct protocol arp_ops = {
 121         .key = 0x0806,
 122         .print_full = arp,
 123         .print_less = arp_less,
 124 };
 125
 126 EXPORT_SYMBOL(arp_ops);