On 08/18/2017 11:15 AM, Mark Cave-Ayland wrote:
Separate out the standard ethernet CRC32 calculation into a new net_crc32()
function, renaming the constant POLYNOMIAL to POLYNOMIAL_BE to make it clear
that this is a big-endian CRC32 calculation.
Then remove the existing implementation from compute_mcast_idx() and call the
new function in its place.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayl...@ilande.co.uk>
---
include/net/net.h | 3 ++-
net/net.c | 16 +++++++++++-----
2 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/include/net/net.h b/include/net/net.h
index 1c55a93..586098c 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -227,7 +227,8 @@ NetClientState *net_hub_port_find(int hub_id);
void qdev_set_nic_properties(DeviceState *dev, NICInfo *nd);
-#define POLYNOMIAL 0x04c11db6
+#define POLYNOMIAL_BE 0x04c11db6
+uint32_t net_crc32(const uint8_t *p, int len);
unsigned compute_mcast_idx(const uint8_t *ep);
#define vmstate_offset_macaddr(_state, _field) \
diff --git a/net/net.c b/net/net.c
index 0e28099..a856907 100644
--- a/net/net.c
+++ b/net/net.c
@@ -1568,25 +1568,31 @@ int net_client_parse(QemuOptsList *opts_list, const
char *optarg)
/* From FreeBSD */
/* XXX: optimize */
-unsigned compute_mcast_idx(const uint8_t *ep)
+uint32_t net_crc32(const uint8_t *p, int len)
imho there is no point in using signed length.
{
uint32_t crc;
int carry, i, j;
uint8_t b;
crc = 0xffffffff;
- for (i = 0; i < 6; i++) {
- b = *ep++;
+ for (i = 0; i < len; i++) {
+ b = *p++;
for (j = 0; j < 8; j++) {
carry = ((crc & 0x80000000L) ? 1 : 0) ^ (b & 0x01);
crc <<= 1;
b >>= 1;
if (carry) {
- crc = ((crc ^ POLYNOMIAL) | carry);
+ crc = ((crc ^ POLYNOMIAL_BE) | carry);
}
}
}
- return crc >> 26;
+
+ return crc;
+}
+
+unsigned compute_mcast_idx(const uint8_t *ep)
+{
+ return net_crc32(ep, 6) >> 26;
while here let's use ETH_ALEN
}
QemuOptsList qemu_netdev_opts = {
with "uint32_t net_crc32(const uint8_t *p, size_t len);":
Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org>