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[2/4] net: introduce net_crc32_le() function

Message ID 1503065708-28277-3-git-send-email-mark.cave-ayland@ilande.co.uk (mailing list archive)
State New, archived
Headers show

Commit Message

Mark Cave-Ayland Aug. 18, 2017, 2:15 p.m. UTC 
This provides a standard ethernet CRC32 little-endian implementation.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
---
 include/net/net.h |    2 ++
 net/net.c         |   22 ++++++++++++++++++++++
 2 files changed, 24 insertions(+)

Comments

Philippe Mathieu-Daudé Aug. 18, 2017, 4:54 p.m. UTC | #1 
On 08/18/2017 11:15 AM, Mark Cave-Ayland wrote:
> This provides a standard ethernet CRC32 little-endian implementation.
> 
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---
>   include/net/net.h |    2 ++
>   net/net.c         |   22 ++++++++++++++++++++++
>   2 files changed, 24 insertions(+)
> 
> diff --git a/include/net/net.h b/include/net/net.h
> index 586098c..4afac1a 100644
> --- a/include/net/net.h
> +++ b/include/net/net.h
> @@ -228,7 +228,9 @@ NetClientState *net_hub_port_find(int hub_id);
>   void qdev_set_nic_properties(DeviceState *dev, NICInfo *nd);
>   
>   #define POLYNOMIAL_BE 0x04c11db6
> +#define POLYNOMIAL_LE 0xedb88320
>   uint32_t net_crc32(const uint8_t *p, int len);
> +uint32_t net_crc32_le(const uint8_t *p, int len);

same here, with size_t len:
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

>   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 a856907..c99e705 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -1590,6 +1590,28 @@ uint32_t net_crc32(const uint8_t *p, int len)
>       return crc;
>   }
>   
> +uint32_t net_crc32_le(const uint8_t *p, int len)
> +{
> +    uint32_t crc;
> +    int carry, i, j;
> +    uint8_t b;
> +
> +    crc = 0xffffffff;
> +    for (i = 0; i < len; i++) {
> +        b = *p++;
> +        for (j = 0; j < 8; j++) {
> +            carry = (crc & 0x1) ^ (b & 0x01);
> +            crc >>= 1;
> +            b >>= 1;
> +            if (carry) {
> +                crc = crc ^ POLYNOMIAL_LE;
> +            }
> +        }
> +    }
> +
> +    return crc;
> +}
> +
>   unsigned compute_mcast_idx(const uint8_t *ep)
>   {
>       return net_crc32(ep, 6) >> 26;
>
diff mbox

Patch

diff --git a/include/net/net.h b/include/net/net.h
index 586098c..4afac1a 100644
--- a/include/net/net.h
+++ b/include/net/net.h
@@ -228,7 +228,9 @@  NetClientState *net_hub_port_find(int hub_id);
 void qdev_set_nic_properties(DeviceState *dev, NICInfo *nd);
 
 #define POLYNOMIAL_BE 0x04c11db6
+#define POLYNOMIAL_LE 0xedb88320
 uint32_t net_crc32(const uint8_t *p, int len);
+uint32_t net_crc32_le(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 a856907..c99e705 100644
--- a/net/net.c
+++ b/net/net.c
@@ -1590,6 +1590,28 @@  uint32_t net_crc32(const uint8_t *p, int len)
     return crc;
 }
 
+uint32_t net_crc32_le(const uint8_t *p, int len)
+{
+    uint32_t crc;
+    int carry, i, j;
+    uint8_t b;
+
+    crc = 0xffffffff;
+    for (i = 0; i < len; i++) {
+        b = *p++;
+        for (j = 0; j < 8; j++) {
+            carry = (crc & 0x1) ^ (b & 0x01);
+            crc >>= 1;
+            b >>= 1;
+            if (carry) {
+                crc = crc ^ POLYNOMIAL_LE;
+            }
+        }
+    }
+
+    return crc;
+}
+
 unsigned compute_mcast_idx(const uint8_t *ep)
 {
     return net_crc32(ep, 6) >> 26;