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| author | Michael Tuexen <tuexen@FreeBSD.org> | 2022-02-17 18:23:59 +0000 |
|---|---|---|
| committer | Michael Tuexen <tuexen@FreeBSD.org> | 2022-02-23 00:13:10 +0000 |
| commit | b6e6748b2b4aca5b30226213201fdc61caee3cd3 (patch) | |
| tree | 82056ff35517ca7ae64640ba8a4dbf4920a356a9 | |
| parent | 8147d64bf18166bd4868821e8492d8bc3e8daa1d (diff) | |
| download | src-b6e6748b2b4aca5b30226213201fdc61caee3cd3.tar.gz src-b6e6748b2b4aca5b30226213201fdc61caee3cd3.zip | |
sctp: avoid undefined behaviour and cleanup the code.
(cherry picked from commit 76e03cc940fed57d580b1d5c0605e8af2e14f05b)
| -rw-r--r-- | sys/netinet/sctp_crc32.c | 29 |
1 files changed, 11 insertions, 18 deletions
diff --git a/sys/netinet/sctp_crc32.c b/sys/netinet/sctp_crc32.c index 97b881bb5062..9e17637d74d6 100644 --- a/sys/netinet/sctp_crc32.c +++ b/sys/netinet/sctp_crc32.c @@ -52,32 +52,25 @@ __FBSDID("$FreeBSD$"); static uint32_t sctp_finalize_crc32c(uint32_t crc32c) { - uint32_t result; #if BYTE_ORDER == BIG_ENDIAN - uint8_t byte0, byte1, byte2, byte3; + uint32_t byte0, byte1, byte2, byte3; #endif - /* Complement the result */ - result = ~crc32c; #if BYTE_ORDER == BIG_ENDIAN /* - * For BIG-ENDIAN platforms the result is in little-endian form. So - * we must swap the bytes to return the result in network byte - * order. + * For BIG-ENDIAN platforms, the result is in LITTLE-ENDIAN byte + * order. For LITTLE-ENDIAN platforms, the result is in in + * BIG-ENDIAN byte order. So for BIG-ENDIAN platforms the bytes must + * be swapped to return the result always in network byte order (aka + * BIG-ENDIAN). */ - byte0 = result & 0x000000ff; - byte1 = (result >> 8) & 0x000000ff; - byte2 = (result >> 16) & 0x000000ff; - byte3 = (result >> 24) & 0x000000ff; + byte0 = crc32c & 0x000000ff; + byte1 = (crc32c >> 8) & 0x000000ff; + byte2 = (crc32c >> 16) & 0x000000ff; + byte3 = (crc32c >> 24) & 0x000000ff; crc32c = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3); -#else - /* - * For LITTLE ENDIAN platforms the result is in already in network - * byte order. - */ - crc32c = result; #endif - return (crc32c); + return (~crc32c); } static int |