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networking: consolidate the IP checksum code. -129 bytes.

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Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Baruch Siach
2011-09-07 17:52:37 +02:00
committed by Denys Vlasenko
parent 8c84f7545c
commit e8f36330d9
7 changed files with 48 additions and 95 deletions
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35
networking/traceroute.c
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@@ -418,39 +418,6 @@ wait_for_reply(len_and_sockaddr *from_lsa, struct sockaddr *to, unsigned *timest
return read_len;
}
/*
* Checksum routine for Internet Protocol family headers (C Version)
*/
static uint16_t
in_cksum(uint16_t *addr, int len)
{
int nleft = len;
uint16_t *w = addr;
uint16_t answer;
int sum = 0;
/*
* Our algorithm is simple, using a 32 bit accumulator (sum),
* we add sequential 16 bit words to it, and at the end, fold
* back all the carry bits from the top 16 bits into the lower
* 16 bits.
*/
while (nleft > 1) {
sum += *w++;
nleft -= 2;
}
/* mop up an odd byte, if necessary */
if (nleft == 1)
sum += *(unsigned char *)w;
/* add back carry outs from top 16 bits to low 16 bits */
sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
sum += (sum >> 16); /* add carry */
answer = ~sum; /* truncate to 16 bits */
return answer;
}
static void
send_probe(int seq, int ttl)
{
@@ -477,7 +444,7 @@ send_probe(int seq, int ttl)
/* Always calculate checksum for icmp packets */
outicmp->icmp_cksum = 0;
outicmp->icmp_cksum = in_cksum((uint16_t *)outicmp,
outicmp->icmp_cksum = inet_cksum((uint16_t *)outicmp,
packlen - (sizeof(*outip) + optlen));
if (outicmp->icmp_cksum == 0)
outicmp->icmp_cksum = 0xffff;