arch/all-pc/boot/grub2-aros/grub-core/net/icmp.c

   1 /*
   2  *  GRUB  --  GRand Unified Bootloader
   3  *  Copyright (C) 2010,2011  Free Software Foundation, Inc.
   4  *
   5  *  GRUB is free software: you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation, either version 3 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  GRUB is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <grub/net.h>
  20 #include <grub/net/ip.h>
  21 #include <grub/net/netbuff.h>
  22
  23 struct icmp_header
  24 {
  25   grub_uint8_t type;
  26   grub_uint8_t code;
  27   grub_uint16_t checksum;
  28 } __attribute__ ((packed));
  29
  30 struct ping_header
  31 {
  32   grub_uint16_t id;
  33   grub_uint16_t seq;
  34 } __attribute__ ((packed));
  35
  36 enum
  37   {
  38     ICMP_ECHO_REPLY = 0,
  39     ICMP_ECHO = 8,
  40   };
  41
  42 grub_err_t
  43 grub_net_recv_icmp_packet (struct grub_net_buff *nb,
  44                            struct grub_net_network_level_interface *inf,
  45                            const grub_net_link_level_address_t *ll_src,
  46                            const grub_net_network_level_address_t *src)
  47 {
  48   struct icmp_header *icmph;
  49   grub_err_t err;
  50   grub_uint16_t checksum;
  51
  52   /* Ignore broadcast.  */
  53   if (!inf)
  54     {
  55       grub_netbuff_free (nb);
  56       return GRUB_ERR_NONE;
  57     }
  58
  59   icmph = (struct icmp_header *) nb->data;
  60
  61   if (nb->tail - nb->data < (grub_ssize_t) sizeof (*icmph))
  62     {
  63       grub_netbuff_free (nb);
  64       return GRUB_ERR_NONE;
  65     }
  66
  67   checksum = icmph->checksum;
  68   icmph->checksum = 0;
  69   if (checksum != grub_net_ip_chksum (nb->data, nb->tail - nb->data))
  70     {
  71       icmph->checksum = checksum;
  72       return GRUB_ERR_NONE;
  73     }
  74   icmph->checksum = checksum;
  75
  76   err = grub_netbuff_pull (nb, sizeof (*icmph));
  77   if (err)
  78     return err;
  79
  80   switch (icmph->type)
  81     {
  82     case ICMP_ECHO:
  83       {
  84         struct grub_net_buff *nb_reply;
  85         struct icmp_header *icmphr;
  86         if (icmph->code)
  87           break;
  88         nb_reply = grub_netbuff_alloc (nb->tail - nb->data + 512);
  89         if (!nb_reply)
  90           {
  91             grub_netbuff_free (nb);
  92             return grub_errno;
  93           }
  94         err = grub_netbuff_reserve (nb_reply, nb->tail - nb->data + 512);
  95         if (err)
  96           goto ping_fail;
  97         err = grub_netbuff_push (nb_reply, nb->tail - nb->data);
  98         if (err)
  99           goto ping_fail;
 100         grub_memcpy (nb_reply->data, nb->data, nb->tail - nb->data);
 101         err = grub_netbuff_push (nb_reply, sizeof (*icmphr));
 102         if (err)
 103           goto ping_fail;
 104         icmphr = (struct icmp_header *) nb_reply->data;
 105         icmphr->type = ICMP_ECHO_REPLY;
 106         icmphr->code = 0;
 107         icmphr->checksum = 0;
 108         icmphr->checksum = grub_net_ip_chksum ((void *) nb_reply->data,
 109                                                nb_reply->tail - nb_reply->data);
 110         err = grub_net_send_ip_packet (inf, src, ll_src,
 111                                        nb_reply, GRUB_NET_IP_ICMP);
 112
 113       ping_fail:
 114         grub_netbuff_free (nb);
 115         grub_netbuff_free (nb_reply);
 116         return err;
 117       }
 118     };
 119
 120   grub_netbuff_free (nb);
 121   return GRUB_ERR_NONE;
 122 }