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Add IP checksumming functions to qemu (Gerd Hoffmann)

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This can be shared between the e1000, virtio-net, and xennet.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4971 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aliguori 2008-07-29 19:40:04 +00:00
parent dd5e6304aa
commit 48c643630c
3 changed files with 95 additions and 1 deletions
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2
Makefile.target
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@ -472,7 +472,7 @@ endif #CONFIG_DARWIN_USER
# System emulator target
ifndef CONFIG_USER_ONLY
OBJS=vl.o osdep.o monitor.o pci.o loader.o isa_mmio.o machine.o
OBJS=vl.o osdep.o monitor.o pci.o loader.o isa_mmio.o machine.o net-checksum.o
ifdef CONFIG_WIN32
OBJS+=block-raw-win32.o
else

87
net-checksum.c Normal file
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@ -0,0 +1,87 @@
/*
* IP checksumming functions.
* (c) 2008 Gerd Hoffmann <kraxel@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; under version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "hw/hw.h"
#include "net.h"
#define PROTO_TCP 6
#define PROTO_UDP 17
uint32_t net_checksum_add(int len, uint8_t *buf)
{
uint32_t sum = 0;
int i;
for (i = 0; i < len; i++) {
if (i & 1)
sum += (uint32_t)buf[i];
else
sum += (uint32_t)buf[i] << 8;
}
return sum;
}
uint16_t net_checksum_finish(uint32_t sum)
{
while (sum>>16)
sum = (sum & 0xFFFF)+(sum >> 16);
return ~sum;
}
uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto,
uint8_t *addrs, uint8_t *buf)
{
uint32_t sum = 0;
sum += net_checksum_add(length, buf); // payload
sum += net_checksum_add(8, addrs); // src + dst address
sum += proto + length; // protocol & length
return net_checksum_finish(sum);
}
void net_checksum_calculate(uint8_t *data, int length)
{
int hlen, plen, proto, csum_offset;
uint16_t csum;
if ((data[14] & 0xf0) != 0x40)
return; /* not IPv4 */
hlen = (data[14] & 0x0f) * 4;
plen = (data[16] << 8 | data[17]) - hlen;
proto = data[23];
switch (proto) {
case PROTO_TCP:
csum_offset = 16;
break;
case PROTO_UDP:
csum_offset = 6;
break;
default:
return;
}
if (plen < csum_offset+2)
return;
data[14+hlen+csum_offset] = 0;
data[14+hlen+csum_offset+1] = 0;
csum = net_checksum_tcpudp(plen, proto, data+14+12, data+14+hlen);
data[14+hlen+csum_offset] = csum >> 8;
data[14+hlen+csum_offset+1] = csum & 0xff;
}

7
net.h
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@ -48,4 +48,11 @@ struct NICInfo {
extern int nb_nics;
extern NICInfo nd_table[MAX_NICS];
/* checksumming functions (net-checksum.c) */
uint32_t net_checksum_add(int len, uint8_t *buf);
uint16_t net_checksum_finish(uint32_t sum);
uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto,
uint8_t *addrs, uint8_t *buf);
void net_checksum_calculate(uint8_t *data, int length);
#endif