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119 lines
2.9 KiB
119 lines
2.9 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#ifndef __UM_CHECKSUM_H |
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#define __UM_CHECKSUM_H |
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#include <linux/string.h> |
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#include <linux/in6.h> |
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#include <linux/uaccess.h> |
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/* |
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* computes the checksum of a memory block at buff, length len, |
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* and adds in "sum" (32-bit) |
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* |
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* returns a 32-bit number suitable for feeding into itself |
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* or csum_tcpudp_magic |
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* |
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* this function must be called with even lengths, except |
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* for the last fragment, which may be odd |
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* |
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* it's best to have buff aligned on a 32-bit boundary |
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*/ |
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extern __wsum csum_partial(const void *buff, int len, __wsum sum); |
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/** |
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* csum_fold - Fold and invert a 32bit checksum. |
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* sum: 32bit unfolded sum |
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* |
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* Fold a 32bit running checksum to 16bit and invert it. This is usually |
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* the last step before putting a checksum into a packet. |
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* Make sure not to mix with 64bit checksums. |
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*/ |
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static inline __sum16 csum_fold(__wsum sum) |
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{ |
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__asm__( |
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" addl %1,%0\n" |
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" adcl $0xffff,%0" |
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: "=r" (sum) |
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: "r" ((__force u32)sum << 16), |
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"0" ((__force u32)sum & 0xffff0000) |
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); |
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return (__force __sum16)(~(__force u32)sum >> 16); |
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} |
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/** |
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* csum_tcpup_nofold - Compute an IPv4 pseudo header checksum. |
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* @saddr: source address |
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* @daddr: destination address |
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* @len: length of packet |
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* @proto: ip protocol of packet |
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* @sum: initial sum to be added in (32bit unfolded) |
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* |
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* Returns the pseudo header checksum the input data. Result is |
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* 32bit unfolded. |
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*/ |
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static inline __wsum |
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csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len, |
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__u8 proto, __wsum sum) |
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{ |
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asm(" addl %1, %0\n" |
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" adcl %2, %0\n" |
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" adcl %3, %0\n" |
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" adcl $0, %0\n" |
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: "=r" (sum) |
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: "g" (daddr), "g" (saddr), "g" ((len + proto) << 8), "0" (sum)); |
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return sum; |
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} |
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/* |
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* computes the checksum of the TCP/UDP pseudo-header |
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* returns a 16-bit checksum, already complemented |
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*/ |
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static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, |
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__u32 len, __u8 proto, |
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__wsum sum) |
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{ |
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return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); |
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} |
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/** |
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* ip_fast_csum - Compute the IPv4 header checksum efficiently. |
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* iph: ipv4 header |
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* ihl: length of header / 4 |
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*/ |
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static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) |
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{ |
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unsigned int sum; |
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asm( " movl (%1), %0\n" |
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" subl $4, %2\n" |
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" jbe 2f\n" |
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" addl 4(%1), %0\n" |
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" adcl 8(%1), %0\n" |
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" adcl 12(%1), %0\n" |
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"1: adcl 16(%1), %0\n" |
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" lea 4(%1), %1\n" |
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" decl %2\n" |
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" jne 1b\n" |
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" adcl $0, %0\n" |
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" movl %0, %2\n" |
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" shrl $16, %0\n" |
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" addw %w2, %w0\n" |
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" adcl $0, %0\n" |
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" notl %0\n" |
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"2:" |
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/* Since the input registers which are loaded with iph and ipl |
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are modified, we must also specify them as outputs, or gcc |
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will assume they contain their original values. */ |
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: "=r" (sum), "=r" (iph), "=r" (ihl) |
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: "1" (iph), "2" (ihl) |
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: "memory"); |
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return (__force __sum16)sum; |
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} |
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#ifdef CONFIG_X86_32 |
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# include "checksum_32.h" |
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#else |
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# include "checksum_64.h" |
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#endif |
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#endif
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