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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/arm/include/asm/checksum.h
Initial import
Diffstat (limited to 'arch/arm/include/asm/checksum.h')
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diff --git a/arch/arm/include/asm/checksum.h b/arch/arm/include/asm/checksum.h
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+++ b/arch/arm/include/asm/checksum.h
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+/*
+ * arch/arm/include/asm/checksum.h
+ *
+ * IP checksum routines
+ *
+ * Copyright (C) Original authors of ../asm-i386/checksum.h
+ * Copyright (C) 1996-1999 Russell King
+ */
+#ifndef __ASM_ARM_CHECKSUM_H
+#define __ASM_ARM_CHECKSUM_H
+
+#include <linux/in6.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
+ */
+__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
+ */
+
+__wsum
+csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
+
+__wsum
+csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *err_ptr);
+
+/*
+ * Fold a partial checksum without adding pseudo headers
+ */
+static inline __sum16 csum_fold(__wsum sum)
+{
+ __asm__(
+ "add %0, %1, %1, ror #16 @ csum_fold"
+ : "=r" (sum)
+ : "r" (sum)
+ : "cc");
+ return (__force __sum16)(~(__force u32)sum >> 16);
+}
+
+/*
+ * This is a version of ip_compute_csum() optimized for IP headers,
+ * which always checksum on 4 octet boundaries.
+ */
+static inline __sum16
+ip_fast_csum(const void *iph, unsigned int ihl)
+{
+ unsigned int tmp1;
+ __wsum sum;
+
+ __asm__ __volatile__(
+ "ldr %0, [%1], #4 @ ip_fast_csum \n\
+ ldr %3, [%1], #4 \n\
+ sub %2, %2, #5 \n\
+ adds %0, %0, %3 \n\
+ ldr %3, [%1], #4 \n\
+ adcs %0, %0, %3 \n\
+ ldr %3, [%1], #4 \n\
+1: adcs %0, %0, %3 \n\
+ ldr %3, [%1], #4 \n\
+ tst %2, #15 @ do this carefully \n\
+ subne %2, %2, #1 @ without destroying \n\
+ bne 1b @ the carry flag \n\
+ adcs %0, %0, %3 \n\
+ adc %0, %0, #0"
+ : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (tmp1)
+ : "1" (iph), "2" (ihl)
+ : "cc", "memory");
+ return csum_fold(sum);
+}
+
+static inline __wsum
+csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
+ unsigned short proto, __wsum sum)
+{
+ u32 lenprot = len | proto << 16;
+ if (__builtin_constant_p(sum) && sum == 0) {
+ __asm__(
+ "adds %0, %1, %2 @ csum_tcpudp_nofold0 \n\t"
+#ifdef __ARMEB__
+ "adcs %0, %0, %3 \n\t"
+#else
+ "adcs %0, %0, %3, ror #8 \n\t"
+#endif
+ "adc %0, %0, #0"
+ : "=&r" (sum)
+ : "r" (daddr), "r" (saddr), "r" (lenprot)
+ : "cc");
+ } else {
+ __asm__(
+ "adds %0, %1, %2 @ csum_tcpudp_nofold \n\t"
+ "adcs %0, %0, %3 \n\t"
+#ifdef __ARMEB__
+ "adcs %0, %0, %4 \n\t"
+#else
+ "adcs %0, %0, %4, ror #8 \n\t"
+#endif
+ "adc %0, %0, #0"
+ : "=&r"(sum)
+ : "r" (sum), "r" (daddr), "r" (saddr), "r" (lenprot)
+ : "cc");
+ }
+ 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, unsigned short len,
+ unsigned short 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
+extern __wsum
+__csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __be32 len,
+ __be32 proto, __wsum sum);
+
+static inline __sum16
+csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __u32 len,
+ unsigned short proto, __wsum sum)
+{
+ return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl(len),
+ htonl(proto), sum));
+}
+#endif