[PATCH v4 0/2] staging: rtl8188eu: Replace a custom function with crc32_le()

[PATCH v4 0/2] staging: rtl8188eu: Replace a custom function with crc32_le()

[Fabio M. De Francesco]

Use kernel API crc32_le() in place of the custom getcrc32(). Remove no
more used functions and variables after the changes made by patch 1/2.

Fabio M. De Francesco (2):
  staging: rtl8188eu: Replace a custom function with crc32_le()
  staging: rtl8188eu: Remove no more used functions and variables

 drivers/staging/rtl8188eu/core/rtw_security.c | 81 +++++--------------
 1 file changed, 19 insertions(+), 62 deletions(-)

-- 
2.32.0

[PATCH v4 1/2] staging: rtl8188eu: Replace a custom function with crc32_le()

[Fabio M. De Francesco]

Use crc32_le() in place of the custom getcrc32().

Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
---

v3 --> v4:
According to a suggestion of David Laight, kill the casts of crc to __le32.

v2 --> v3:
Join two related patches in a series because they must be applied in
order (first 1/2, then 2/2). Rebase to the current Greg K-H's tree and resend.

v1 --> v2:
Use cpu_to_le32() to assign native endian return value of crc32_le to
crc in little endian byte order.

 drivers/staging/rtl8188eu/core/rtw_security.c | 45 ++++++++-----------
 1 file changed, 19 insertions(+), 26 deletions(-)

diff --git a/drivers/staging/rtl8188eu/core/rtw_security.c b/drivers/staging/rtl8188eu/core/rtw_security.c
index 1b2cb6196463..7001f24f118d 100644
--- a/drivers/staging/rtl8188eu/core/rtw_security.c
+++ b/drivers/staging/rtl8188eu/core/rtw_security.c
@@ -11,6 +11,7 @@
 #include <wifi.h>
 #include <osdep_intf.h>
 #include <net/lib80211.h>
+#include <linux/types.h>
 
 /* WEP related ===== */
 
@@ -111,21 +112,6 @@ static void crc32_init(void)
 	bcrc32initialized = 1;
 }
 
-static __le32 getcrc32(u8 *buf, int len)
-{
-	u8 *p;
-	u32  crc;
-
-	if (bcrc32initialized == 0)
-		crc32_init();
-
-	crc = 0xffffffff;       /* preload shift register, per CRC-32 spec */
-
-	for (p = buf; len > 0; ++p, --len)
-		crc = crc32_table[(crc ^ *p) & 0xff] ^ (crc >> 8);
-	return cpu_to_le32(~crc);    /* transmit complement, per CRC-32 spec */
-}
-
 /* Need to consider the fragment  situation */
 void rtw_wep_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
 {
@@ -564,7 +550,10 @@ u32	rtw_tkip_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
 	u32	pnh;
 	u8	rc4key[16];
 	u8   ttkey[16];
-	u8	crc[4];
+	union {
+		__le32 f0;
+		u8 f1[4];
+	} crc;
 	u8   hw_hdr_offset = 0;
 	struct arc4context mycontext;
 	int			curfragnum, length;
@@ -609,17 +598,18 @@ u32	rtw_tkip_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
 
 				if ((curfragnum + 1) == pattrib->nr_frags) {	/* 4 the last fragment */
 					length = pattrib->last_txcmdsz - pattrib->hdrlen - pattrib->iv_len - pattrib->icv_len;
-					*((__le32 *)crc) = getcrc32(payload, length);/* modified by Amy*/
+					crc.f0 = cpu_to_le32(~crc32_le(~0, payload, length));
 
 					arcfour_init(&mycontext, rc4key, 16);
 					arcfour_encrypt(&mycontext, payload, payload, length);
-					arcfour_encrypt(&mycontext, payload + length, crc, 4);
+					arcfour_encrypt(&mycontext, payload + length, crc.f1, 4);
 				} else {
 					length = pxmitpriv->frag_len - pattrib->hdrlen - pattrib->iv_len - pattrib->icv_len;
-					*((__le32 *)crc) = getcrc32(payload, length);/* modified by Amy*/
+					crc.f0 = cpu_to_le32(~crc32_le(~0, payload, length));
+
 					arcfour_init(&mycontext, rc4key, 16);
 					arcfour_encrypt(&mycontext, payload, payload, length);
-					arcfour_encrypt(&mycontext, payload + length, crc, 4);
+					arcfour_encrypt(&mycontext, payload + length, crc.f1, 4);
 
 					pframe += pxmitpriv->frag_len;
 					pframe = (u8 *)round_up((size_t)(pframe), 4);
@@ -639,7 +629,10 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, struct recv_frame *precvframe)
 	u32 pnh;
 	u8   rc4key[16];
 	u8   ttkey[16];
-	u8	crc[4];
+	union {
+		__le32 f0;
+		u8 f1[4];
+	} crc;
 	struct arc4context mycontext;
 	int			length;
 	u8	*pframe, *payload, *iv, *prwskey;
@@ -682,12 +675,12 @@ u32 rtw_tkip_decrypt(struct adapter *padapter, struct recv_frame *precvframe)
 			arcfour_init(&mycontext, rc4key, 16);
 			arcfour_encrypt(&mycontext, payload, payload, length);
 
-			*((__le32 *)crc) = getcrc32(payload, length - 4);
+			crc.f0 = cpu_to_le32(~crc32_le(~0, payload, length - 4));
 
-			if (crc[3] != payload[length - 1] ||
-			    crc[2] != payload[length - 2] ||
-			    crc[1] != payload[length - 3] ||
-			    crc[0] != payload[length - 4])
+			if (crc.f1[3] != payload[length - 1] ||
+			    crc.f1[2] != payload[length - 2] ||
+			    crc.f1[1] != payload[length - 3] ||
+			    crc.f1[0] != payload[length - 4])
 				res = _FAIL;
 		} else {
 			res = _FAIL;
-- 
2.32.0

[PATCH v4 2/2] staging: rtl8188eu: Remove no more used functions and variables

[Fabio M. De Francesco]

Remove the functions and variables from rtw_security.c that are no more
necessary since the patch that replaces getcrc32() with crc32_le().

Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
---

v3 --> v4:
No changes.

v2 --> v3:
Join two related patches in a series because they must be applied in
order (first 1/2, then 2/2). Rebase to the current Greg K-H's tree and resend.

v1 -> v2:
Update the commit message with the URL of v2 of the above-mentioned
patch.

 drivers/staging/rtl8188eu/core/rtw_security.c | 36 -------------------
 1 file changed, 36 deletions(-)

diff --git a/drivers/staging/rtl8188eu/core/rtw_security.c b/drivers/staging/rtl8188eu/core/rtw_security.c
index 7001f24f118d..7185c1ae2ab8 100644
--- a/drivers/staging/rtl8188eu/core/rtw_security.c
+++ b/drivers/staging/rtl8188eu/core/rtw_security.c
@@ -76,42 +76,6 @@ static void arcfour_encrypt(struct arc4context *parc4ctx, u8 *dest, u8 *src, u32
 		dest[i] = src[i] ^ (unsigned char)arcfour_byte(parc4ctx);
 }
 
-static int bcrc32initialized;
-static u32 crc32_table[256];
-
-static u8 crc32_reverseBit(u8 data)
-{
-	return (u8)((data << 7) & 0x80) | ((data << 5) & 0x40) | ((data << 3) & 0x20) |
-		   ((data << 1) & 0x10) | ((data >> 1) & 0x08) | ((data >> 3) & 0x04) |
-		   ((data >> 5) & 0x02) | ((data >> 7) & 0x01);
-}
-
-static void crc32_init(void)
-{
-	int i, j;
-	u32 c;
-	u8 *p = (u8 *)&c, *p1;
-	u8 k;
-
-	if (bcrc32initialized == 1)
-		return;
-
-	c = 0x12340000;
-
-	for (i = 0; i < 256; ++i) {
-		k = crc32_reverseBit((u8)i);
-		for (c = ((u32)k) << 24, j = 8; j > 0; --j)
-			c = c & 0x80000000 ? (c << 1) ^ CRC32_POLY : (c << 1);
-		p1 = (u8 *)&crc32_table[i];
-
-		p1[0] = crc32_reverseBit(p[3]);
-		p1[1] = crc32_reverseBit(p[2]);
-		p1[2] = crc32_reverseBit(p[1]);
-		p1[3] = crc32_reverseBit(p[0]);
-	}
-	bcrc32initialized = 1;
-}
-
 /* Need to consider the fragment  situation */
 void rtw_wep_encrypt(struct adapter *padapter, struct xmit_frame *pxmitframe)
 {
-- 
2.32.0

Re: [PATCH v4 0/2] staging: rtl8188eu: Replace a custom function with crc32_le()

[Greg Kroah-Hartman]

On Fri, Jul 23, 2021 at 09:26:18PM +0200, Fabio M. De Francesco wrote:
> Use kernel API crc32_le() in place of the custom getcrc32(). Remove no
> more used functions and variables after the changes made by patch 1/2.
> 
> Fabio M. De Francesco (2):
>   staging: rtl8188eu: Replace a custom function with crc32_le()
>   staging: rtl8188eu: Remove no more used functions and variables
> 
>  drivers/staging/rtl8188eu/core/rtw_security.c | 81 +++++--------------
>  1 file changed, 19 insertions(+), 62 deletions(-)

Much nicer, thanks!

Re: [PATCH v4 0/2] staging: rtl8188eu: Replace a custom function with crc32_le()

[Fabio M. De Francesco]

On Tuesday, July 27, 2021 3:17:37 PM CEST Greg Kroah-Hartman wrote:
> On Fri, Jul 23, 2021 at 09:26:18PM +0200, Fabio M. De Francesco wrote:
> > Use kernel API crc32_le() in place of the custom getcrc32(). Remove no
> > more used functions and variables after the changes made by patch 1/2.
> > 
> > Fabio M. De Francesco (2):
> >   staging: rtl8188eu: Replace a custom function with crc32_le()
> >   staging: rtl8188eu: Remove no more used functions and variables
> >  
> >  drivers/staging/rtl8188eu/core/rtw_security.c | 81 +++++--------------
> >  1 file changed, 19 insertions(+), 62 deletions(-)
> 
> Much nicer, thanks!

Glad you appreciated my solution to this problem. There is another driver 
(rtl8723bs) that needs a change like this. I will post a similar patch by 
tomorrow.

Thanks very much,

Fabio