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udp: Generic functions to set checksum

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Added udp_set_csum and udp6_set_csum functions to set UDP checksums
in packets. These are for simple UDP packets such as those that might
be created in UDP tunnels.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tom Herbert 2014-06-04 17:19:48 -07:00 committed by David S. Miller
parent 6579867c8b
commit af5fcba7f3
4 changed files with 96 additions and 0 deletions
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12
include/net/ip6_checksum.h
View File

@ -82,5 +82,17 @@ static inline void tcp_v6_send_check(struct sock *sk, struct sk_buff *skb)
}
#endif
static inline __sum16 udp_v6_check(int len,
const struct in6_addr *saddr,
const struct in6_addr *daddr,
__wsum base)
{
return csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP, base);
}
void udp6_set_csum(bool nocheck, struct sk_buff *skb,
const struct in6_addr *saddr,
const struct in6_addr *daddr, int len);
int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto);
#endif

9
include/net/udp.h
View File

@ -147,6 +147,15 @@ static inline __wsum udp_csum(struct sk_buff *skb)
return csum;
}
static inline __sum16 udp_v4_check(int len, __be32 saddr,
__be32 daddr, __wsum base)
{
return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base);
}
void udp_set_csum(bool nocheck, struct sk_buff *skb,
__be32 saddr, __be32 daddr, int len);
/* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
static inline void udp_lib_hash(struct sock *sk)
{

37
net/ipv4/udp.c
View File

@ -762,6 +762,43 @@ void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
}
EXPORT_SYMBOL_GPL(udp4_hwcsum);
/* Function to set UDP checksum for an IPv4 UDP packet. This is intended
* for the simple case like when setting the checksum for a UDP tunnel.
*/
void udp_set_csum(bool nocheck, struct sk_buff *skb,
__be32 saddr, __be32 daddr, int len)
{
struct udphdr *uh = udp_hdr(skb);
if (nocheck)
uh->check = 0;
else if (skb_is_gso(skb))
uh->check = ~udp_v4_check(len, saddr, daddr, 0);
else if (skb_dst(skb) && skb_dst(skb)->dev &&
(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM)) {
BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL);
skb->ip_summed = CHECKSUM_PARTIAL;
skb->csum_start = skb_transport_header(skb) - skb->head;
skb->csum_offset = offsetof(struct udphdr, check);
uh->check = ~udp_v4_check(len, saddr, daddr, 0);
} else {
__wsum csum;
BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL);
uh->check = 0;
csum = skb_checksum(skb, 0, len, 0);
uh->check = udp_v4_check(len, saddr, daddr, csum);
if (uh->check == 0)
uh->check = CSUM_MANGLED_0;
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
}
EXPORT_SYMBOL(udp_set_csum);
static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
{
struct sock *sk = skb->sk;

38
net/ipv6/ip6_checksum.c
View File

@ -84,3 +84,41 @@ int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto)
ip6_compute_pseudo);
}
EXPORT_SYMBOL(udp6_csum_init);
/* Function to set UDP checksum for an IPv6 UDP packet. This is intended
* for the simple case like when setting the checksum for a UDP tunnel.
*/
void udp6_set_csum(bool nocheck, struct sk_buff *skb,
const struct in6_addr *saddr,
const struct in6_addr *daddr, int len)
{
struct udphdr *uh = udp_hdr(skb);
if (nocheck)
uh->check = 0;
else if (skb_is_gso(skb))
uh->check = ~udp_v6_check(len, saddr, daddr, 0);
else if (skb_dst(skb) && skb_dst(skb)->dev &&
(skb_dst(skb)->dev->features & NETIF_F_IPV6_CSUM)) {
BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL);
skb->ip_summed = CHECKSUM_PARTIAL;
skb->csum_start = skb_transport_header(skb) - skb->head;
skb->csum_offset = offsetof(struct udphdr, check);
uh->check = ~udp_v6_check(len, saddr, daddr, 0);
} else {
__wsum csum;
BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL);
uh->check = 0;
csum = skb_checksum(skb, 0, len, 0);
uh->check = udp_v6_check(len, saddr, daddr, csum);
if (uh->check == 0)
uh->check = CSUM_MANGLED_0;
skb->ip_summed = CHECKSUM_UNNECESSARY;
}
}
EXPORT_SYMBOL(udp6_set_csum);