linux/net/ipv6/ip6_checksum.c
Bjørn Mork 84a3e72c3a ipv6: log src and dst along with "udp checksum is 0"
These info messages are rather pointless without any means to identify
the source of the bogus packets.  Logging the src and dst addresses and
ports may help a bit.

Cc: Joe Perches <joe@perches.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-26 15:46:25 -05:00

100 lines
2.4 KiB
C

#include <net/ip.h>
#include <net/udp.h>
#include <net/udplite.h>
#include <asm/checksum.h>
#ifndef _HAVE_ARCH_IPV6_CSUM
__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
const struct in6_addr *daddr,
__u32 len, unsigned short proto,
__wsum csum)
{
int carry;
__u32 ulen;
__u32 uproto;
__u32 sum = (__force u32)csum;
sum += (__force u32)saddr->s6_addr32[0];
carry = (sum < (__force u32)saddr->s6_addr32[0]);
sum += carry;
sum += (__force u32)saddr->s6_addr32[1];
carry = (sum < (__force u32)saddr->s6_addr32[1]);
sum += carry;
sum += (__force u32)saddr->s6_addr32[2];
carry = (sum < (__force u32)saddr->s6_addr32[2]);
sum += carry;
sum += (__force u32)saddr->s6_addr32[3];
carry = (sum < (__force u32)saddr->s6_addr32[3]);
sum += carry;
sum += (__force u32)daddr->s6_addr32[0];
carry = (sum < (__force u32)daddr->s6_addr32[0]);
sum += carry;
sum += (__force u32)daddr->s6_addr32[1];
carry = (sum < (__force u32)daddr->s6_addr32[1]);
sum += carry;
sum += (__force u32)daddr->s6_addr32[2];
carry = (sum < (__force u32)daddr->s6_addr32[2]);
sum += carry;
sum += (__force u32)daddr->s6_addr32[3];
carry = (sum < (__force u32)daddr->s6_addr32[3]);
sum += carry;
ulen = (__force u32)htonl((__u32) len);
sum += ulen;
carry = (sum < ulen);
sum += carry;
uproto = (__force u32)htonl(proto);
sum += uproto;
carry = (sum < uproto);
sum += carry;
return csum_fold((__force __wsum)sum);
}
EXPORT_SYMBOL(csum_ipv6_magic);
#endif
int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto)
{
int err;
UDP_SKB_CB(skb)->partial_cov = 0;
UDP_SKB_CB(skb)->cscov = skb->len;
if (proto == IPPROTO_UDPLITE) {
err = udplite_checksum_init(skb, uh);
if (err)
return err;
}
if (uh->check == 0) {
/* RFC 2460 section 8.1 says that we SHOULD log
this error. Well, it is reasonable.
*/
LIMIT_NETDEBUG(KERN_INFO "IPv6: udp checksum is 0 for [%pI6c]:%u->[%pI6c]:%u\n",
&ipv6_hdr(skb)->saddr, ntohs(uh->source),
&ipv6_hdr(skb)->daddr, ntohs(uh->dest));
return 1;
}
if (skb->ip_summed == CHECKSUM_COMPLETE &&
!csum_ipv6_magic(&ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr,
skb->len, proto, skb->csum))
skb->ip_summed = CHECKSUM_UNNECESSARY;
if (!skb_csum_unnecessary(skb))
skb->csum = ~csum_unfold(csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
&ipv6_hdr(skb)->daddr,
skb->len, proto, 0));
return 0;
}
EXPORT_SYMBOL(udp6_csum_init);