Commit 84026301 authored by Dmitry Fleytman's avatar Dmitry Fleytman Committed by Stefan Hajnoczi
Browse files

net: iovec checksum calculator 



Signed-off-by: default avatarDmitry Fleytman <dmitry@daynix.com>
Signed-off-by: default avatarYan Vugenfirer <yan@daynix.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 5acf5ea4

include/net/checksum.h

+12 −0
Original line number Diff line number Diff line
@@ -38,4 +38,16 @@ net_raw_checksum(uint8_t *data, int length) 
    return net_checksum_finish(net_checksum_add(length, data));

}



/**

 * net_checksum_add_iov: scatter-gather vector checksumming

 *

 * @iov: input scatter-gather array

 * @iov_cnt: number of array elements

 * @iov_off: starting iov offset for checksumming

 * @size: length of data to be checksummed

 */

uint32_t net_checksum_add_iov(const struct iovec *iov,

                              const unsigned int iov_cnt,

                              uint32_t iov_off, uint32_t size);



#endif /* QEMU_NET_CHECKSUM_H */

net/checksum.c

+29 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
 *  along with this program; if not, see <http://www.gnu.org/licenses/>.

 */



#include "qemu-common.h"

#include "net/checksum.h"



#define PROTO_TCP  6
@@ -84,3 +85,31 @@ void net_checksum_calculate(uint8_t *data, int length) 
    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;

}