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-rw-r--r--arch/x86/include/asm/checksum_32.h186
1 files changed, 186 insertions, 0 deletions
diff --git a/arch/x86/include/asm/checksum_32.h b/arch/x86/include/asm/checksum_32.h
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+++ b/arch/x86/include/asm/checksum_32.h
@@ -0,0 +1,186 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_CHECKSUM_32_H
+#define _ASM_X86_CHECKSUM_32_H
+
+#include <linux/in6.h>
+#include <linux/uaccess.h>
+
+/*
+ * computes the checksum of a memory block at buff, length len,
+ * and adds in "sum" (32-bit)
+ *
+ * returns a 32-bit number suitable for feeding into itself
+ * or csum_tcpudp_magic
+ *
+ * this function must be called with even lengths, except
+ * for the last fragment, which may be odd
+ *
+ * it's best to have buff aligned on a 32-bit boundary
+ */
+asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum);
+
+/*
+ * the same as csum_partial, but copies from src while it
+ * checksums, and handles user-space pointer exceptions correctly, when needed.
+ *
+ * here even more important to align src and dst on a 32-bit (or even
+ * better 64-bit) boundary
+ */
+
+asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
+
+/*
+ * Note: when you get a NULL pointer exception here this means someone
+ * passed in an incorrect kernel address to one of these functions.
+ *
+ * If you use these functions directly please don't forget the
+ * access_ok().
+ */
+static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len)
+{
+ return csum_partial_copy_generic(src, dst, len);
+}
+
+static inline __wsum csum_and_copy_from_user(const void __user *src,
+ void *dst, int len)
+{
+ __wsum ret;
+
+ might_sleep();
+ if (!user_access_begin(src, len))
+ return 0;
+ ret = csum_partial_copy_generic((__force void *)src, dst, len);
+ user_access_end();
+
+ return ret;
+}
+
+/*
+ * This is a version of ip_compute_csum() optimized for IP headers,
+ * which always checksum on 4 octet boundaries.
+ *
+ * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
+ * Arnt Gulbrandsen.
+ */
+static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
+{
+ unsigned int sum;
+
+ asm volatile("movl (%1), %0 ;\n"
+ "subl $4, %2 ;\n"
+ "jbe 2f ;\n"
+ "addl 4(%1), %0 ;\n"
+ "adcl 8(%1), %0 ;\n"
+ "adcl 12(%1), %0;\n"
+ "1: adcl 16(%1), %0 ;\n"
+ "lea 4(%1), %1 ;\n"
+ "decl %2 ;\n"
+ "jne 1b ;\n"
+ "adcl $0, %0 ;\n"
+ "movl %0, %2 ;\n"
+ "shrl $16, %0 ;\n"
+ "addw %w2, %w0 ;\n"
+ "adcl $0, %0 ;\n"
+ "notl %0 ;\n"
+ "2: ;\n"
+ /* Since the input registers which are loaded with iph and ihl
+ are modified, we must also specify them as outputs, or gcc
+ will assume they contain their original values. */
+ : "=r" (sum), "=r" (iph), "=r" (ihl)
+ : "1" (iph), "2" (ihl)
+ : "memory");
+ return (__force __sum16)sum;
+}
+
+/*
+ * Fold a partial checksum
+ */
+
+static inline __sum16 csum_fold(__wsum sum)
+{
+ asm("addl %1, %0 ;\n"
+ "adcl $0xffff, %0 ;\n"
+ : "=r" (sum)
+ : "r" ((__force u32)sum << 16),
+ "0" ((__force u32)sum & 0xffff0000));
+ return (__force __sum16)(~(__force u32)sum >> 16);
+}
+
+static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
+ __u32 len, __u8 proto,
+ __wsum sum)
+{
+ asm("addl %1, %0 ;\n"
+ "adcl %2, %0 ;\n"
+ "adcl %3, %0 ;\n"
+ "adcl $0, %0 ;\n"
+ : "=r" (sum)
+ : "g" (daddr), "g"(saddr),
+ "g" ((len + proto) << 8), "0" (sum));
+ return sum;
+}
+
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 16-bit checksum, already complemented
+ */
+static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
+ __u32 len, __u8 proto,
+ __wsum sum)
+{
+ return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
+}
+
+/*
+ * this routine is used for miscellaneous IP-like checksums, mainly
+ * in icmp.c
+ */
+
+static inline __sum16 ip_compute_csum(const void *buff, int len)
+{
+ return csum_fold(csum_partial(buff, len, 0));
+}
+
+#define _HAVE_ARCH_IPV6_CSUM
+static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
+ const struct in6_addr *daddr,
+ __u32 len, __u8 proto, __wsum sum)
+{
+ asm("addl 0(%1), %0 ;\n"
+ "adcl 4(%1), %0 ;\n"
+ "adcl 8(%1), %0 ;\n"
+ "adcl 12(%1), %0 ;\n"
+ "adcl 0(%2), %0 ;\n"
+ "adcl 4(%2), %0 ;\n"
+ "adcl 8(%2), %0 ;\n"
+ "adcl 12(%2), %0 ;\n"
+ "adcl %3, %0 ;\n"
+ "adcl %4, %0 ;\n"
+ "adcl $0, %0 ;\n"
+ : "=&r" (sum)
+ : "r" (saddr), "r" (daddr),
+ "r" (htonl(len)), "r" (htonl(proto)), "0" (sum)
+ : "memory");
+
+ return csum_fold(sum);
+}
+
+/*
+ * Copy and checksum to user
+ */
+static inline __wsum csum_and_copy_to_user(const void *src,
+ void __user *dst,
+ int len)
+{
+ __wsum ret;
+
+ might_sleep();
+ if (!user_access_begin(dst, len))
+ return 0;
+
+ ret = csum_partial_copy_generic(src, (__force void *)dst, len);
+ user_access_end();
+ return ret;
+}
+
+#endif /* _ASM_X86_CHECKSUM_32_H */