| Message ID | 20171205081744.6563-3-mark.cave-ayland@ilande.co.uk |
|---|---|
| State | New |
| Headers | show |
| Series | net: introduce common net_crc32() and net_crc32_le() functions | expand |
On 12/05/2017 02:17 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(+) Reviewed-by: Eric Blake <eblake@redhat.com> > + if (carry) { > + crc = crc ^ POLYNOMIAL_LE; > + } Worth writing as 'crc ^= POLYNOMIAL_LE;'?
On 12/05/2017 05:17 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> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> > --- > 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 586098cb94..4afac1a9dd 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 02a567c18f..38008fe8e7 100644 > --- a/net/net.c > +++ b/net/net.c > @@ -1603,6 +1603,28 @@ 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; >
On 05/12/17 14:31, Eric Blake wrote: > On 12/05/2017 02:17 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(+) > > Reviewed-by: Eric Blake <eblake@redhat.com> > >> + if (carry) { >> + crc = crc ^ POLYNOMIAL_LE; >> + } > > Worth writing as 'crc ^= POLYNOMIAL_LE;'? Yes, works for me. ATB, Mark.
diff --git a/include/net/net.h b/include/net/net.h index 586098cb94..4afac1a9dd 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 02a567c18f..38008fe8e7 100644 --- a/net/net.c +++ b/net/net.c @@ -1603,6 +1603,28 @@ 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;
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(+)