From 215b01bba8bc662d35f72b084700b192d367dfb4 Mon Sep 17 00:00:00 2001
From: Bartlomiej Sieka <tur@semihalf.com>
Date: Tue, 22 Apr 2008 12:27:56 +0200
Subject: Add support for calculating hashes with watchdog triggering

Implement watchodg-aware variants of hash calculation functions:
- crc32_wd()
- md5_wd()
- sha1_csum_wd()
The above functions calculate the hash of the input buffer in chunks,
triggering the watchdog after processing each chunk. The chunk size
is given as a function call parameter.

Signed-off-by: Bartlomiej Sieka <tur@semihalf.com>
---
 lib_generic/crc32.c | 27 +++++++++++++++++++++++++++
 lib_generic/md5.c   | 36 ++++++++++++++++++++++++++++++++++++
 lib_generic/sha1.c  | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 96 insertions(+)

(limited to 'lib_generic')

diff --git a/lib_generic/crc32.c b/lib_generic/crc32.c
index b882daa10..58cd22eb7 100644
--- a/lib_generic/crc32.c
+++ b/lib_generic/crc32.c
@@ -198,3 +198,30 @@ uint32_t ZEXPORT crc32_no_comp(uint32_t crc, const Bytef *buf, uInt len)
 }
 
 #endif
+
+/*
+ * Calculate the crc32 checksum triggering the watchdog every 'chunk_sz' bytes
+ * of input.
+ */
+ulong crc32_wd (ulong crc, const unsigned char *buf, uint len, uint chunk_sz)
+{
+#if defined(CONFIG_HW_WATCHDOG) || defined(CONFIG_WATCHDOG)
+	const unsigned char *end, *curr;
+	int chunk;
+
+	curr = buf;
+	end = buf + len;
+	while (curr < end) {
+		chunk = end - curr;
+		if (chunk > chunk_sz)
+			chunk = chunk_sz;
+		crc = crc32 (crc, curr, chunk);
+		curr += chunk;
+		WATCHDOG_RESET ();
+	}
+#else
+        crc = crc32 (crc, buf, len);
+#endif
+
+	return crc;
+}
diff --git a/lib_generic/md5.c b/lib_generic/md5.c
index 3cee431c7..20178b8dc 100644
--- a/lib_generic/md5.c
+++ b/lib_generic/md5.c
@@ -272,3 +272,39 @@ md5 (unsigned char *input, int len, unsigned char output[16])
 	MD5Update(&context, input, len);
 	MD5Final(output, &context);
 }
+
+
+/*
+ * Calculate and store in 'output' the MD5 digest of 'len' bytes at 'input'.
+ * 'output' must have enough space to hold 16 bytes. If 'chunk' Trigger the
+ * watchdog every 'chunk_sz' bytes of input processed.
+ */
+void
+md5_wd (unsigned char *input, int len, unsigned char output[16],
+	unsigned int chunk_sz)
+{
+	struct MD5Context context;
+#if defined(CONFIG_HW_WATCHDOG) || defined(CONFIG_WATCHDOG)
+	unsigned char *end, *curr;
+	int chunk;
+#endif
+
+	MD5Init(&context);
+
+#if defined(CONFIG_HW_WATCHDOG) || defined(CONFIG_WATCHDOG)
+	curr = input;
+	end = input + len;
+	while (curr < end) {
+		chunk = end - curr;
+		if (chunk > chunk_sz)
+			chunk = chunk_sz;
+		MD5Update(&context, curr, chunk);
+		curr += chunk;
+		WATCHDOG_RESET ();
+	}
+#else
+	MD5Update(&context, input, len);
+#endif
+
+	MD5Final(output, &context);
+}
diff --git a/lib_generic/sha1.c b/lib_generic/sha1.c
index 08ffa6b9b..69506592f 100644
--- a/lib_generic/sha1.c
+++ b/lib_generic/sha1.c
@@ -308,6 +308,39 @@ void sha1_csum (unsigned char *input, int ilen, unsigned char output[20])
 	sha1_finish (&ctx, output);
 }
 
+/*
+ * Output = SHA-1( input buffer ). Trigger the watchdog every 'chunk_sz'
+ * bytes of input processed.
+ */
+void sha1_csum_wd (unsigned char *input, int ilen, unsigned char output[20],
+			unsigned int chunk_sz)
+{
+	sha1_context ctx;
+#if defined(CONFIG_HW_WATCHDOG) || defined(CONFIG_WATCHDOG)
+	unsigned char *end, *curr;
+	int chunk;
+#endif
+
+	sha1_starts (&ctx);
+
+#if defined(CONFIG_HW_WATCHDOG) || defined(CONFIG_WATCHDOG)
+	curr = input;
+	end = input + ilen;
+	while (curr < end) {
+		chunk = end - curr;
+		if (chunk > chunk_sz)
+			chunk = chunk_sz;
+		sha1_update (&ctx, curr, chunk);
+		curr += chunk;
+		WATCHDOG_RESET ();
+	}
+#else
+	sha1_update (&ctx, input, ilen);
+#endif
+
+	sha1_finish (&ctx, output);
+}
+
 /*
  * Output = HMAC-SHA-1( input buffer, hmac key )
  */
-- 
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