common/sctp_crc32: accept NULL buffer pointer

If we get NULL we behave as if it were a zero-filled buffer.

Signed-off-by: Sage Weil <sage@inktank.com>

diff --git a/src/common/sctp_crc32.c b/src/common/sctp_crc32.c
index 7e2678a2b7ceba7815fdb2444cbe821a83c78e61..2b4fceccf230e2a2aa064ea20ebb92cd7652dfd6 100644 (file)
--- a/src/common/sctp_crc32.c
+++ b/src/common/sctp_crc32.c
@@ -580,6 +580,58 @@ sctp_crc32c_sb8_64_bit(uint32_t crc,
        return crc;
 }
 
+static uint32_t
+sctp_crc32c_sb8_64_bit_zero(uint32_t crc,
+    uint32_t length,
+    uint32_t offset)
+{
+       uint32_t li;
+       uint32_t term1, term2;
+       uint32_t running_length;
+       uint32_t end_bytes;
+       uint32_t init_bytes;
+
+       init_bytes = (4-offset) & 0x3;
+
+       if (init_bytes > length)
+               init_bytes = length;
+
+       running_length = ((length - init_bytes) / 8) * 8;
+       end_bytes = length - init_bytes - running_length;
+
+       for (li = 0; li < init_bytes; li++)
+               crc = sctp_crc_tableil8_o32[crc & 0x000000FF] ^
+                   (crc >> 8);
+       for (li = 0; li < running_length / 8; li++) {
+               term1 = sctp_crc_tableil8_o88[crc & 0x000000FF] ^
+                   sctp_crc_tableil8_o80[(crc >> 8) & 0x000000FF];
+               term2 = crc >> 16;
+               crc = term1 ^
+                   sctp_crc_tableil8_o72[term2 & 0x000000FF] ^
+                   sctp_crc_tableil8_o64[(term2 >> 8) & 0x000000FF];
+
+#if BYTE_ORDER == BIG_ENDIAN
+               crc ^= sctp_crc_tableil8_o56[0];
+               crc ^= sctp_crc_tableil8_o48[0];
+               crc ^= sctp_crc_tableil8_o40[0];
+               crc ^= sctp_crc_tableil8_o32[0];
+#else
+               term1 = sctp_crc_tableil8_o56[0] ^
+                       sctp_crc_tableil8_o48[0];
+
+               term2 = 0;
+               crc = crc ^
+                   term1 ^
+                   sctp_crc_tableil8_o40[term2 & 0x000000FF] ^
+                   sctp_crc_tableil8_o32[(term2 >> 8) & 0x000000FF];
+#endif
+       }
+       for (li = 0; li < end_bytes; li++)
+               crc = sctp_crc_tableil8_o32[crc] ^
+                   (crc >> 8);
+       return crc;
+}
+
 
 /**
  *
@@ -606,7 +658,10 @@ update_crc32(uint32_t crc32c,
                return (crc32c);
        }
        offset = ((uintptr_t) buffer) & 0x3;
-       return (sctp_crc32c_sb8_64_bit(crc32c, buffer, length, offset));
+       if (buffer)
+               return (sctp_crc32c_sb8_64_bit(crc32c, buffer, length, offset));
+       else
+               return (sctp_crc32c_sb8_64_bit_zero(crc32c, length, offset));
 }
 
 uint32_t sctp_crc_c[256] = {