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Diffstat (limited to 'include/net/checksum.h')
| -rw-r--r-- | include/net/checksum.h | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/include/net/checksum.h b/include/net/checksum.h new file mode 100644 index 000000000..051307cc8 --- /dev/null +++ b/include/net/checksum.h @@ -0,0 +1,190 @@ +/* + * INET An implementation of the TCP/IP protocol suite for the LINUX + * operating system. INET is implemented using the BSD Socket + * interface as the means of communication with the user level. + * + * Checksumming functions for IP, TCP, UDP and so on + * + * Authors: Jorge Cwik, <jorge@laser.satlink.net> + * Arnt Gulbrandsen, <agulbra@nvg.unit.no> + * Borrows very liberally from tcp.c and ip.c, see those + * files for more names. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#ifndef _CHECKSUM_H +#define _CHECKSUM_H + +#include <linux/errno.h> +#include <asm/types.h> +#include <asm/byteorder.h> +#include <linux/uaccess.h> +#include <asm/checksum.h> + +#ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER +static inline +__wsum csum_and_copy_from_user (const void __user *src, void *dst, + int len, __wsum sum, int *err_ptr) +{ + if (access_ok(VERIFY_READ, src, len)) + return csum_partial_copy_from_user(src, dst, len, sum, err_ptr); + + if (len) + *err_ptr = -EFAULT; + + return sum; +} +#endif + +#ifndef HAVE_CSUM_COPY_USER +static __inline__ __wsum csum_and_copy_to_user +(const void *src, void __user *dst, int len, __wsum sum, int *err_ptr) +{ + sum = csum_partial(src, len, sum); + + if (access_ok(VERIFY_WRITE, dst, len)) { + if (copy_to_user(dst, src, len) == 0) + return sum; + } + if (len) + *err_ptr = -EFAULT; + + return (__force __wsum)-1; /* invalid checksum */ +} +#endif + +#ifndef HAVE_ARCH_CSUM_ADD +static inline __wsum csum_add(__wsum csum, __wsum addend) +{ + u32 res = (__force u32)csum; + res += (__force u32)addend; + return (__force __wsum)(res + (res < (__force u32)addend)); +} +#endif + +static inline __wsum csum_sub(__wsum csum, __wsum addend) +{ + return csum_add(csum, ~addend); +} + +static inline __sum16 csum16_add(__sum16 csum, __be16 addend) +{ + u16 res = (__force u16)csum; + + res += (__force u16)addend; + return (__force __sum16)(res + (res < (__force u16)addend)); +} + +static inline __sum16 csum16_sub(__sum16 csum, __be16 addend) +{ + return csum16_add(csum, ~addend); +} + +static inline __wsum +csum_block_add(__wsum csum, __wsum csum2, int offset) +{ + u32 sum = (__force u32)csum2; + + /* rotate sum to align it with a 16b boundary */ + if (offset & 1) + sum = ror32(sum, 8); + + return csum_add(csum, (__force __wsum)sum); +} + +static inline __wsum +csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len) +{ + return csum_block_add(csum, csum2, offset); +} + +static inline __wsum +csum_block_sub(__wsum csum, __wsum csum2, int offset) +{ + return csum_block_add(csum, ~csum2, offset); +} + +static inline __wsum csum_unfold(__sum16 n) +{ + return (__force __wsum)n; +} + +static inline __wsum csum_partial_ext(const void *buff, int len, __wsum sum) +{ + return csum_partial(buff, len, sum); +} + +#define CSUM_MANGLED_0 ((__force __sum16)0xffff) + +static inline void csum_replace_by_diff(__sum16 *sum, __wsum diff) +{ + *sum = csum_fold(csum_add(diff, ~csum_unfold(*sum))); +} + +static inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to) +{ + __wsum tmp = csum_sub(~csum_unfold(*sum), (__force __wsum)from); + + *sum = csum_fold(csum_add(tmp, (__force __wsum)to)); +} + +/* Implements RFC 1624 (Incremental Internet Checksum) + * 3. Discussion states : + * HC' = ~(~HC + ~m + m') + * m : old value of a 16bit field + * m' : new value of a 16bit field + */ +static inline void csum_replace2(__sum16 *sum, __be16 old, __be16 new) +{ + *sum = ~csum16_add(csum16_sub(~(*sum), old), new); +} + +static inline void csum_replace(__wsum *csum, __wsum old, __wsum new) +{ + *csum = csum_add(csum_sub(*csum, old), new); +} + +struct sk_buff; +void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb, + __be32 from, __be32 to, bool pseudohdr); +void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb, + const __be32 *from, const __be32 *to, + bool pseudohdr); +void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb, + __wsum diff, bool pseudohdr); + +static inline void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb, + __be16 from, __be16 to, + bool pseudohdr) +{ + inet_proto_csum_replace4(sum, skb, (__force __be32)from, + (__force __be32)to, pseudohdr); +} + +static inline __wsum remcsum_adjust(void *ptr, __wsum csum, + int start, int offset) +{ + __sum16 *psum = (__sum16 *)(ptr + offset); + __wsum delta; + + /* Subtract out checksum up to start */ + csum = csum_sub(csum, csum_partial(ptr, start, 0)); + + /* Set derived checksum in packet */ + delta = csum_sub((__force __wsum)csum_fold(csum), + (__force __wsum)*psum); + *psum = csum_fold(csum); + + return delta; +} + +static inline void remcsum_unadjust(__sum16 *psum, __wsum delta) +{ + *psum = csum_fold(csum_sub(delta, (__force __wsum)*psum)); +} + +#endif |