Move the checksum code out into its own file so it can be used elsewhere.
Also use a new version which supports a length which is not a multiple of
2 and add a new function to add two checksums.
Signed-off-by: Simon Glass s...@chromium.org
---
Changes in v3:
- Add new patch to move checksum to its own file in net/
Changes in v2: None
include/net.h | 30 +
net/Makefile | 1 +
net/checksum.c | 60 ++
3 files changed, 91 insertions(+)
create mode 100644 net/checksum.c
diff --git a/include/net.h b/include/net.h
index 3da35fe..73ea88b 100644
--- a/include/net.h
+++ b/include/net.h
@@ -482,6 +482,36 @@ extern void net_set_ip_header(uchar *pkt, IPaddr_t dest,
IPaddr_t source);
extern void net_set_udp_header(uchar *pkt, IPaddr_t dest, int dport,
int sport, int len);
+/**
+ * compute_ip_checksum() - Compute IP checksum
+ *
+ * @addr: Address to check (must be 16-bit aligned)
+ * @nbytes:Number of bytes to check (normally a multiple of 2)
+ * @return 16-bit IP checksum
+ */
+unsigned compute_ip_checksum(const void *addr, unsigned nbytes);
+
+/**
+ * add_ip_checksums() - add two IP checksums
+ *
+ * @offset:Offset of first sum (if odd we do a byte-swap)
+ * @sum: First checksum
+ * @new_sum: New checksum to add
+ * @return updated 16-bit IP checksum
+ */
+unsigned add_ip_checksums(unsigned offset, unsigned sum, unsigned new_sum);
+
+/**
+ * ip_checksum_ok() - check if a checksum is correct
+ *
+ * This works by making sure the checksum sums to 0
+ *
+ * @addr: Address to check (must be 16-bit aligned)
+ * @nbytes:Number of bytes to check (normally a multiple of 2)
+ * @return true if the checksum matches, false if not
+ */
+int ip_checksum_ok(const void *addr, unsigned nbytes);
+
/* Checksum */
extern int NetCksumOk(uchar *, int); /* Return true if cksum OK */
extern uintNetCksum(uchar *, int); /* Calculate the checksum */
diff --git a/net/Makefile b/net/Makefile
index 9425950..e9cc8ad 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -7,6 +7,7 @@
#ccflags-y += -DDEBUG
+obj-y += checksum.o
obj-$(CONFIG_CMD_NET) += arp.o
obj-$(CONFIG_CMD_NET) += bootp.o
obj-$(CONFIG_CMD_CDP) += cdp.o
diff --git a/net/checksum.c b/net/checksum.c
new file mode 100644
index 000..a8c9ff5
--- /dev/null
+++ b/net/checksum.c
@@ -0,0 +1,60 @@
+/*
+ * This file was originally taken from the FreeBSD project.
+ *
+ * Copyright (c) 2001 Charles Mott c...@linktel.net
+ * Copyright (c) 2008 coresystems GmbH
+ * All rights reserved.
+ *
+ * SPDX-License-Identifier:BSD-2-Clause
+ */
+
+#include common.h
+#include net.h
+
+unsigned compute_ip_checksum(const void *vptr, unsigned nbytes)
+{
+ int sum, oddbyte;
+ const unsigned short *ptr = vptr;
+
+ sum = 0;
+ while (nbytes 1) {
+ sum += *ptr++;
+ nbytes -= 2;
+ }
+ if (nbytes == 1) {
+ oddbyte = 0;
+ ((u8 *)oddbyte)[0] = *(u8 *)ptr;
+ ((u8 *)oddbyte)[1] = 0;
+ sum += oddbyte;
+ }
+ sum = (sum 16) + (sum 0x);
+ sum += (sum 16);
+ sum = ~sum 0x;
+
+ return sum;
+}
+
+unsigned add_ip_checksums(unsigned offset, unsigned sum, unsigned new)
+{
+ unsigned long checksum;
+
+ sum = ~sum 0x;
+ new = ~new 0x;
+ if (offset 1) {
+ /*
+* byte-swap the sum if it came from an odd offset; since the
+* computation is endian independant this works.
+*/
+ new = ((new 8) 0xff) | ((new 8) 0xff00);
+ }
+ checksum = sum + new;
+ if (checksum 0x)
+ checksum -= 0x;
+
+ return (~checksum) 0x;
+}
+
+int ip_checksum_ok(const void *addr, unsigned nbytes)
+{
+ return !(compute_ip_checksum(addr, nbytes) 0xfffe);
+}
--
2.2.0.rc0.207.ga3a616c
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