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Message-ID: <alpine.DEB.2.02.1405282113290.6331@tomh.mtv.corp.google.com>
Date: Wed, 28 May 2014 21:23:27 -0700 (PDT)
From: Tom Herbert <therbert@...gle.com>
To: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 1/7] 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@...gle.com>
---
include/net/ip6_checksum.h | 45 +++++++++++++++++++++++++++++++++++++++++++++
include/net/udp.h | 42 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 87 insertions(+)
diff --git a/include/net/ip6_checksum.h b/include/net/ip6_checksum.h
index 8ac5c21..7382a12 100644
--- a/include/net/ip6_checksum.h
+++ b/include/net/ip6_checksum.h
@@ -82,5 +82,50 @@ 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);
+}
+
+
+/* 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.
+ */
+static inline void udp6_set_csum(struct sock *sk, struct sk_buff *skb,
+ const struct in6_addr *saddr,
+ const struct in6_addr *daddr, int len)
+{
+ struct udphdr *uh = udp_hdr(skb);
+
+ if (udp_get_no_check6_tx(sk))
+ 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;
+ }
+}
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..a8a6d69 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -147,6 +147,48 @@ 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);
+}
+
+/* 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.
+ */
+static inline void udp_set_csum(struct sock *sk, struct sk_buff *skb,
+ __be32 saddr, __be32 daddr, int len)
+{
+ struct udphdr *uh = udp_hdr(skb);
+
+ if (sk->sk_no_check_tx)
+ 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;
+ }
+}
+
/* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
static inline void udp_lib_hash(struct sock *sk)
{
--
1.9.1.423.g4596e3a
--
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