From af5fcba7f38f3166392f4087ab734433c84f160b Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Wed, 4 Jun 2014 17:19:48 -0700 Subject: [PATCH] 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: Tom Herbert Signed-off-by: David S. Miller --- include/net/ip6_checksum.h | 12 ++++++++++++ include/net/udp.h | 9 +++++++++ net/ipv4/udp.c | 37 +++++++++++++++++++++++++++++++++++++ net/ipv6/ip6_checksum.c | 38 ++++++++++++++++++++++++++++++++++++++ 4 files changed, 96 insertions(+) diff --git a/include/net/ip6_checksum.h b/include/net/ip6_checksum.h index 8ac5c21..55236cb 100644 --- a/include/net/ip6_checksum.h +++ b/include/net/ip6_checksum.h @@ -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 diff --git a/include/net/udp.h b/include/net/udp.h index 5eb8687..2ecfc6e1 100644 --- a/include/net/udp.h +++ b/include/net/udp.h @@ -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) { diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index e07d52b..a84f676 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -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; diff --git a/net/ipv6/ip6_checksum.c b/net/ipv6/ip6_checksum.c index da26224..9a4d732 100644 --- a/net/ipv6/ip6_checksum.c +++ b/net/ipv6/ip6_checksum.c @@ -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); -- 2.7.4