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Don't zero ip->ip_sum during sum validation. This should only

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affect programs that sit on top of divert(4) sockets.  The
multicast routing code already unconditionally zeros the sum
before recalculating.

Any code that unconditionaly sums a packet without first zeroing
the sum (assuming that it's already zero'd) will break.  No such
code seems to exist.
This commit is contained in:
Brian Somers 1997-02-06 11:14:22 +00:00
parent eb20e7557b
commit 47c861ecc7
1 changed files with 4 additions and 3 deletions
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7
sys/netinet/ip_input.c
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@ -216,6 +216,7 @@ ip_input(struct mbuf *m)
struct ipq *fp;
struct in_ifaddr *ia;
int hlen;
u_short sum;
#ifdef DIAGNOSTIC
if ((m->m_flags & M_PKTHDR) == 0)
@ -264,11 +265,11 @@ ip_input(struct mbuf *m)
ip = mtod(m, struct ip *);
}
if (hlen == sizeof(struct ip)) {
ip->ip_sum = in_cksum_hdr(ip);
sum = in_cksum_hdr(ip);
} else {
ip->ip_sum = in_cksum(m, hlen);
sum = in_cksum(m, hlen);
}
if (ip->ip_sum) {
if (sum) {
ipstat.ips_badsum++;
goto bad;
}