Commit 5acf5ea4 authored by Dmitry Fleytman's avatar Dmitry Fleytman Committed by Stefan Hajnoczi
Browse files

Checksum-related utility functions 



net_checksum_add_cont()
checksum calculation for scattered data with odd chunk sizes

net_raw_checksum()
checksum calculation for a buffer

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 20048d0a

include/net/checksum.h

+13 −1
Original line number Diff line number Diff line
@@ -20,10 +20,22 @@ 


#include <stdint.h>



uint32_t net_checksum_add(int len, uint8_t *buf);

uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq);

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);



static inline uint32_t

net_checksum_add(int len, uint8_t *buf)

{

    return net_checksum_add_cont(len, buf, 0);

}



static inline uint16_t

net_raw_checksum(uint8_t *data, int length)

{

    return net_checksum_finish(net_checksum_add(length, data));

}



#endif /* QEMU_NET_CHECKSUM_H */

net/checksum.c

+7 −6
Original line number Diff line number Diff line
@@ -20,16 +20,17 @@ 
#define PROTO_TCP  6

#define PROTO_UDP 17



uint32_t net_checksum_add(int len, uint8_t *buf)

uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq)

{

    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;

    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;

}