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Commit af5fcba7 authored by Tom Herbert's avatar Tom Herbert Committed by David S. Miller
Browse files

udp: Generic functions to set checksum 



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: default avatarTom Herbert <therbert@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6579867c

include/net/ip6_checksum.h

+12 −0
Original line number Diff line number Diff line
@@ -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

include/net/udp.h

+9 −0
Original line number Diff line number Diff line
@@ -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)

{

net/ipv4/udp.c

+37 −0
Original line number Diff line number Diff line
@@ -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;

net/ipv6/ip6_checksum.c

+38 −0
Original line number Diff line number Diff line
@@ -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);