4068579e1e
RFC 6936 relaxes the requirement of RFC 2460 that UDP/IPv6 packets which are received with a zero UDP checksum value must be dropped. RFC 6936 allows zero checksums to support tunnels over UDP. When sk_no_check is set we allow on a socket we allow a zero IPv6 UDP checksum. This is for both sending zero checksum and accepting a zero checksum on receive. Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
87 lines
2.1 KiB
C
87 lines
2.1 KiB
C
#include <net/ip.h>
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#include <net/udp.h>
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#include <net/udplite.h>
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#include <asm/checksum.h>
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#ifndef _HAVE_ARCH_IPV6_CSUM
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__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
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const struct in6_addr *daddr,
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__u32 len, unsigned short proto,
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__wsum csum)
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{
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int carry;
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__u32 ulen;
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__u32 uproto;
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__u32 sum = (__force u32)csum;
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sum += (__force u32)saddr->s6_addr32[0];
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carry = (sum < (__force u32)saddr->s6_addr32[0]);
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sum += carry;
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sum += (__force u32)saddr->s6_addr32[1];
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carry = (sum < (__force u32)saddr->s6_addr32[1]);
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sum += carry;
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sum += (__force u32)saddr->s6_addr32[2];
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carry = (sum < (__force u32)saddr->s6_addr32[2]);
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sum += carry;
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sum += (__force u32)saddr->s6_addr32[3];
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carry = (sum < (__force u32)saddr->s6_addr32[3]);
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sum += carry;
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sum += (__force u32)daddr->s6_addr32[0];
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carry = (sum < (__force u32)daddr->s6_addr32[0]);
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sum += carry;
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sum += (__force u32)daddr->s6_addr32[1];
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carry = (sum < (__force u32)daddr->s6_addr32[1]);
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sum += carry;
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sum += (__force u32)daddr->s6_addr32[2];
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carry = (sum < (__force u32)daddr->s6_addr32[2]);
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sum += carry;
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sum += (__force u32)daddr->s6_addr32[3];
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carry = (sum < (__force u32)daddr->s6_addr32[3]);
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sum += carry;
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ulen = (__force u32)htonl((__u32) len);
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sum += ulen;
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carry = (sum < ulen);
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sum += carry;
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uproto = (__force u32)htonl(proto);
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sum += uproto;
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carry = (sum < uproto);
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sum += carry;
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return csum_fold((__force __wsum)sum);
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}
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EXPORT_SYMBOL(csum_ipv6_magic);
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#endif
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int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto)
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{
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int err;
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UDP_SKB_CB(skb)->partial_cov = 0;
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UDP_SKB_CB(skb)->cscov = skb->len;
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if (proto == IPPROTO_UDPLITE) {
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err = udplite_checksum_init(skb, uh);
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if (err)
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return err;
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}
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/* To support RFC 6936 (allow zero checksum in UDP/IPV6 for tunnels)
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* we accept a checksum of zero here. When we find the socket
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* for the UDP packet we'll check if that socket allows zero checksum
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* for IPv6 (set by socket option).
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*/
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return skb_checksum_init_zero_check(skb, proto, uh->check,
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ip6_compute_pseudo);
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}
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EXPORT_SYMBOL(udp6_csum_init);
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