mirror of
https://github.com/qemu/qemu.git
synced 2024-12-11 12:43:55 +08:00
8402630169
Signed-off-by: Dmitry Fleytman <dmitry@daynix.com> Signed-off-by: Yan Vugenfirer <yan@daynix.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
116 lines
3.0 KiB
C
116 lines
3.0 KiB
C
/*
|
|
* 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 or later 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, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include "qemu-common.h"
|
|
#include "net/checksum.h"
|
|
|
|
#define PROTO_TCP 6
|
|
#define PROTO_UDP 17
|
|
|
|
uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq)
|
|
{
|
|
uint32_t sum = 0;
|
|
int i;
|
|
|
|
for (i = seq; i < seq + len; i++) {
|
|
if (i & 1) {
|
|
sum += (uint32_t)buf[i - seq];
|
|
} else {
|
|
sum += (uint32_t)buf[i - seq] << 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;
|
|
}
|
|
|
|
uint32_t
|
|
net_checksum_add_iov(const struct iovec *iov, const unsigned int iov_cnt,
|
|
uint32_t iov_off, uint32_t size)
|
|
{
|
|
size_t iovec_off, buf_off;
|
|
unsigned int i;
|
|
uint32_t res = 0;
|
|
uint32_t seq = 0;
|
|
|
|
iovec_off = 0;
|
|
buf_off = 0;
|
|
for (i = 0; i < iov_cnt && size; i++) {
|
|
if (iov_off < (iovec_off + iov[i].iov_len)) {
|
|
size_t len = MIN((iovec_off + iov[i].iov_len) - iov_off , size);
|
|
void *chunk_buf = iov[i].iov_base + (iov_off - iovec_off);
|
|
|
|
res += net_checksum_add_cont(len, chunk_buf, seq);
|
|
seq += len;
|
|
|
|
buf_off += len;
|
|
iov_off += len;
|
|
size -= len;
|
|
}
|
|
iovec_off += iov[i].iov_len;
|
|
}
|
|
return res;
|
|
}
|