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authorTom Herbert <therbert@google.com>2014-06-04 17:19:48 -0700
committerDavid S. Miller <davem@davemloft.net>2014-06-04 22:46:38 -0700
commitaf5fcba7f38f3166392f4087ab734433c84f160b (patch)
tree8a6deba10cd458a72e159112ab6381bcaa352b3e /net/ipv6/ip6_checksum.c
parent6579867c8b02606e101a6c511c2511b027ed3f4a (diff)
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 <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/ip6_checksum.c')
-rw-r--r--net/ipv6/ip6_checksum.c38
1 files changed, 38 insertions, 0 deletions
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);

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