From af5fcba7f38f3166392f4087ab734433c84f160b Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Wed, 4 Jun 2014 17:19:48 -0700 Subject: 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 --- net/ipv6/ip6_checksum.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 'net/ipv6') diff --git a/net/ipv6/ip6_checksum.c b/net/ipv6/ip6_checksum.c index da26224a5993..9a4d7322fb22 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); -- cgit