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29 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
30 * in_cksum.c,v 1.2 1994/08/02 07:48:16 davidg Exp
33 #include "qemu/osdep.h"
37 * Checksum routine for Internet Protocol family headers (Portable Version).
39 * This routine is very heavily used in the network
40 * code and should be modified for each CPU to be as fast as possible.
42 * XXX Since we will never span more than 1 mbuf, we can optimise this
45 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
46 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; \
49 int cksum(struct mbuf
*m
, int len
)
53 register int mlen
= 0;
67 w
= mtod(m
, uint16_t *);
77 * Force to even boundary.
79 if ((1 & (uintptr_t)w
) && (mlen
> 0)) {
82 s_util
.c
[0] = *(uint8_t *)w
;
83 w
= (uint16_t *)((int8_t *)w
+ 1);
88 * Unroll the loop to make overhead from
91 while ((mlen
-= 32) >= 0) {
92 sum
+= w
[0]; sum
+= w
[1]; sum
+= w
[2]; sum
+= w
[3];
93 sum
+= w
[4]; sum
+= w
[5]; sum
+= w
[6]; sum
+= w
[7];
94 sum
+= w
[8]; sum
+= w
[9]; sum
+= w
[10]; sum
+= w
[11];
95 sum
+= w
[12]; sum
+= w
[13]; sum
+= w
[14]; sum
+= w
[15];
99 while ((mlen
-= 8) >= 0) {
100 sum
+= w
[0]; sum
+= w
[1]; sum
+= w
[2]; sum
+= w
[3];
104 if (mlen
== 0 && byte_swapped
== 0)
107 while ((mlen
-= 2) >= 0) {
115 s_util
.c
[1] = *(uint8_t *)w
;
121 } else if (mlen
== -1)
122 s_util
.c
[0] = *(uint8_t *)w
;
127 DEBUG_ERROR((dfd
, "cksum: out of data\n"));
128 DEBUG_ERROR((dfd
, " len = %d\n", len
));
132 /* The last mbuf has odd # of bytes. Follow the
133 standard (the odd byte may be shifted left by 8 bits
134 or not as determined by endian-ness of the machine) */
139 return (~sum
& 0xffff);
142 int ip6_cksum(struct mbuf
*m
)
144 /* TODO: Optimize this by being able to pass the ip6_pseudohdr to cksum
145 * separately from the mbuf */
146 struct ip6 save_ip
, *ip
= mtod(m
, struct ip6
*);
147 struct ip6_pseudohdr
*ih
= mtod(m
, struct ip6_pseudohdr
*);
152 ih
->ih_src
= save_ip
.ip_src
;
153 ih
->ih_dst
= save_ip
.ip_dst
;
154 ih
->ih_pl
= htonl((uint32_t)ntohs(save_ip
.ip_pl
));
157 ih
->ih_nh
= save_ip
.ip_nh
;
159 sum
= cksum(m
, ((int)sizeof(struct ip6_pseudohdr
))