src/core/gdbudp.c

   1 /*
   2  * Copyright (C) 2008 Stefan Hajnoczi <stefanha@gmail.com>.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of the
   7  * License, or any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17  */
  18
  19 #include <stdio.h>
  20 #include <string.h>
  21 #include <byteswap.h>
  22 #include <gpxe/iobuf.h>
  23 #include <gpxe/in.h>
  24 #include <gpxe/if_arp.h>
  25 #include <gpxe/if_ether.h>
  26 #include <gpxe/ip.h>
  27 #include <gpxe/udp.h>
  28 #include <gpxe/netdevice.h>
  29 #include <gpxe/nap.h>
  30 #include <gpxe/gdbstub.h>
  31 #include <gpxe/gdbudp.h>
  32
  33 /** @file
  34  *
  35  * GDB over UDP transport
  36  *
  37  */
  38
  39 enum {
  40         DEFAULT_PORT = 43770, /* UDP listen port */
  41 };
  42
  43 struct gdb_transport udp_gdb_transport __gdb_transport;
  44
  45 static struct net_device *netdev;
  46 static uint8_t dest_eth[ETH_ALEN];
  47 static struct sockaddr_in dest_addr;
  48 static struct sockaddr_in source_addr;
  49
  50 static void gdbudp_ensure_netdev_open ( struct net_device *netdev ) {
  51         /* The device may have been closed between breakpoints */
  52         assert ( netdev );
  53         netdev_open ( netdev );
  54
  55         /* Strictly speaking, we may need to close the device when leaving the interrupt handler */
  56 }
  57
  58 static size_t gdbudp_recv ( char *buf, size_t len ) {
  59         struct io_buffer *iob;
  60         struct ethhdr *ethhdr;
  61         struct arphdr *arphdr;
  62         struct iphdr *iphdr;
  63         struct udp_header *udphdr;
  64         size_t payload_len;
  65
  66         gdbudp_ensure_netdev_open ( netdev );
  67
  68         for ( ; ; ) {
  69                 netdev_poll ( netdev );
  70                 while ( ( iob = netdev_rx_dequeue ( netdev ) ) != NULL ) {
  71                         /* Ethernet header */
  72                         if ( iob_len ( iob ) < sizeof ( *ethhdr ) ) {
  73                                 goto bad_packet;
  74                         }
  75                         ethhdr = iob->data;
  76                         iob_pull ( iob, sizeof ( *ethhdr ) );
  77
  78                         /* Handle ARP requests so the client can find our MAC */
  79                         if ( ethhdr->h_protocol == htons ( ETH_P_ARP ) ) {
  80                                 arphdr = iob->data;
  81                                 if ( iob_len ( iob ) < sizeof ( *arphdr ) + 2 * ( ETH_ALEN + sizeof ( struct in_addr ) ) ||
  82                                                 arphdr->ar_hrd != htons ( ARPHRD_ETHER ) ||
  83                                                 arphdr->ar_pro != htons ( ETH_P_IP ) ||
  84                                                 arphdr->ar_hln != ETH_ALEN ||
  85                                                 arphdr->ar_pln != sizeof ( struct in_addr ) ||
  86                                                 arphdr->ar_op != htons ( ARPOP_REQUEST ) ||
  87                                                 * ( uint32_t * ) arp_target_pa ( arphdr ) != source_addr.sin_addr.s_addr ) {
  88                                         goto bad_packet;
  89                                 }
  90
  91                                 /* Generate an ARP reply */
  92                                 arphdr->ar_op = htons ( ARPOP_REPLY );
  93                                 memswap ( arp_sender_pa ( arphdr ), arp_target_pa ( arphdr ), sizeof ( struct in_addr ) );
  94                                 memcpy ( arp_target_ha ( arphdr ), arp_sender_ha ( arphdr ), ETH_ALEN );
  95                                 memcpy ( arp_sender_ha ( arphdr ), netdev->ll_addr, ETH_ALEN );
  96
  97                                 /* Fix up ethernet header */
  98                                 ethhdr = iob_push ( iob, sizeof ( *ethhdr ) );
  99                                 memcpy ( ethhdr->h_dest, ethhdr->h_source, ETH_ALEN );
 100                                 memcpy ( ethhdr->h_source, netdev->ll_addr, ETH_ALEN );
 101
 102                                 netdev_tx ( netdev, iob );
 103                                 continue; /* no need to free iob */
 104                         }
 105
 106                         if ( ethhdr->h_protocol != htons ( ETH_P_IP ) ) {
 107                                 goto bad_packet;
 108                         }
 109
 110                         /* IP header */
 111                         if ( iob_len ( iob ) < sizeof ( *iphdr ) ) {
 112                                 goto bad_packet;
 113                         }
 114                         iphdr = iob->data;
 115                         iob_pull ( iob, sizeof ( *iphdr ) );
 116                         if ( iphdr->protocol != IP_UDP || iphdr->dest.s_addr != source_addr.sin_addr.s_addr ) {
 117                                 goto bad_packet;
 118                         }
 119
 120                         /* UDP header */
 121                         if ( iob_len ( iob ) < sizeof ( *udphdr ) ) {
 122                                 goto bad_packet;
 123                         }
 124                         udphdr = iob->data;
 125                         if ( udphdr->dest != source_addr.sin_port ) {
 126                                 goto bad_packet;
 127                         }
 128
 129                         /* Learn the remote connection details */
 130                         memcpy ( dest_eth, ethhdr->h_source, ETH_ALEN );
 131                         dest_addr.sin_addr.s_addr = iphdr->src.s_addr;
 132                         dest_addr.sin_port = udphdr->src;
 133
 134                         /* Payload */
 135                         payload_len = ntohs ( udphdr->len );
 136                         if ( payload_len < sizeof ( *udphdr ) || payload_len > iob_len ( iob ) ) {
 137                                 goto bad_packet;
 138                         }
 139                         payload_len -= sizeof ( *udphdr );
 140                         iob_pull ( iob, sizeof ( *udphdr ) );
 141                         if ( payload_len > len ) {
 142                                 goto bad_packet;
 143                         }
 144                         memcpy ( buf, iob->data, payload_len );
 145
 146                         free_iob ( iob );
 147                         return payload_len;
 148
 149 bad_packet:
 150                         free_iob ( iob );
 151                 }
 152                 cpu_nap();
 153         }
 154 }
 155
 156 static void gdbudp_send ( const char *buf, size_t len ) {
 157         struct io_buffer *iob;
 158         struct ethhdr *ethhdr;
 159         struct iphdr *iphdr;
 160         struct udp_header *udphdr;
 161
 162         /* Check that we are connected */
 163         if ( dest_addr.sin_port == 0 ) {
 164                 return;
 165         }
 166
 167         gdbudp_ensure_netdev_open ( netdev );
 168
 169         iob = alloc_iob ( sizeof ( *ethhdr ) + sizeof ( *iphdr ) + sizeof ( *udphdr ) + len );
 170         if ( !iob ) {
 171                 return;
 172         }
 173
 174         /* Payload */
 175         iob_reserve ( iob, sizeof ( *ethhdr ) + sizeof ( *iphdr ) + sizeof ( *udphdr ) );
 176         memcpy ( iob_put ( iob, len ), buf, len );
 177
 178         /* UDP header */
 179         udphdr = iob_push ( iob, sizeof ( *udphdr ) );
 180         udphdr->src = source_addr.sin_port;
 181         udphdr->dest = dest_addr.sin_port;
 182         udphdr->len = htons ( iob_len ( iob ) );
 183         udphdr->chksum = 0; /* optional and we are not using it */
 184
 185         /* IP header */
 186         iphdr = iob_push ( iob, sizeof ( *iphdr ) );
 187         memset ( iphdr, 0, sizeof ( *iphdr ) );
 188         iphdr->verhdrlen = ( IP_VER | ( sizeof ( *iphdr ) / 4 ) );
 189         iphdr->service = IP_TOS;
 190         iphdr->len = htons ( iob_len ( iob ) );
 191         iphdr->ttl = IP_TTL;
 192         iphdr->protocol = IP_UDP;
 193         iphdr->dest.s_addr = dest_addr.sin_addr.s_addr;
 194         iphdr->src.s_addr = source_addr.sin_addr.s_addr;
 195         iphdr->chksum = tcpip_chksum ( iphdr, sizeof ( *iphdr ) );
 196
 197         /* Ethernet header */
 198         ethhdr = iob_push ( iob, sizeof ( *ethhdr ) );
 199         memcpy ( ethhdr->h_dest, dest_eth, ETH_ALEN );
 200         memcpy ( ethhdr->h_source, netdev->ll_addr, ETH_ALEN );
 201         ethhdr->h_protocol = htons ( ETH_P_IP );
 202
 203         netdev_tx ( netdev, iob );
 204 }
 205
 206 struct gdb_transport *gdbudp_configure ( const char *name, struct sockaddr_in *addr ) {
 207         struct settings *settings;
 208
 209         /* Release old network device */
 210         netdev_put ( netdev );
 211
 212         netdev = find_netdev ( name );
 213         if ( !netdev ) {
 214                 return NULL;
 215         }
 216
 217         /* Hold network device */
 218         netdev_get ( netdev );
 219
 220         /* Source UDP port */
 221         source_addr.sin_port = ( addr && addr->sin_port ) ? addr->sin_port : htons ( DEFAULT_PORT );
 222
 223         /* Source IP address */
 224         if ( addr && addr->sin_addr.s_addr ) {
 225                 source_addr.sin_addr.s_addr = addr->sin_addr.s_addr;
 226         } else {
 227                 settings = netdev_settings ( netdev );
 228                 fetch_ipv4_setting ( settings, &ip_setting, &source_addr.sin_addr );
 229                 if ( source_addr.sin_addr.s_addr == 0 ) {
 230                         netdev_put ( netdev );
 231                         netdev = NULL;
 232                         return NULL;
 233                 }
 234         }
 235
 236         return &udp_gdb_transport;
 237 }
 238
 239 static int gdbudp_init ( int argc, char **argv ) {
 240         if ( argc != 1 ) {
 241                 printf ( "udp: missing <interface> argument\n" );
 242                 return 1;
 243         }
 244
 245         if ( !gdbudp_configure ( argv[0], NULL ) ) {
 246                 printf ( "%s: device does not exist or has no IP address\n", argv[0] );
 247                 return 1;
 248         }
 249         return 0;
 250 }
 251
 252 struct gdb_transport udp_gdb_transport __gdb_transport = {
 253         .name = "udp",
 254         .init = gdbudp_init,
 255         .send = gdbudp_send,
 256         .recv = gdbudp_recv,
 257 };