1 files changed, 44 insertions, 33 deletions

diff --git a/include/net/udplite.h b/include/net/udplite.h
index afdffe607b2..2caadabcd07 100644
--- a/include/net/udplite.h
+++ b/include/net/udplite.h
@@ -40,7 +40,7 @@ static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
          * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
          * with a zero checksum field are illegal.                            */
 	if (uh->check == 0) {
-		LIMIT_NETDEBUG(KERN_DEBUG "UDPLITE: zeroed checksum field\n");
+		LIMIT_NETDEBUG(KERN_DEBUG "UDPLite: zeroed checksum field\n");
 		return 1;
 	}
 
@@ -52,7 +52,7 @@ static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
 		/*
 		 * Coverage length violates RFC 3828: log and discard silently.
 		 */
-		LIMIT_NETDEBUG(KERN_DEBUG "UDPLITE: bad csum coverage %d/%d\n",
+		LIMIT_NETDEBUG(KERN_DEBUG "UDPLite: bad csum coverage %d/%d\n",
 			       cscov, skb->len);
 		return 1;
 
@@ -66,40 +66,34 @@ static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
 	return 0;
 }
 
-static inline int udplite_sender_cscov(struct udp_sock *up, struct udphdr *uh)
+/* Slow-path computation of checksum. Socket is locked. */
+static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
 {
+	const struct udp_sock *up = udp_sk(skb->sk);
 	int cscov = up->len;
+	__wsum csum = 0;
 
-	/*
-	 * Sender has set `partial coverage' option on UDP-Lite socket
-	 */
-	if (up->pcflag & UDPLITE_SEND_CC)    {
+	if (up->pcflag & UDPLITE_SEND_CC) {
+		/*
+		 * Sender has set `partial coverage' option on UDP-Lite socket.
+		 * The special case "up->pcslen == 0" signifies full coverage.
+		 */
 		if (up->pcslen < up->len) {
-		/* up->pcslen == 0 means that full coverage is required,
-		 * partial coverage only if  0 < up->pcslen < up->len */
-			if (0 < up->pcslen) {
-			       cscov = up->pcslen;
-			}
-			uh->len = htons(up->pcslen);
+			if (0 < up->pcslen)
+				cscov = up->pcslen;
+			udp_hdr(skb)->len = htons(up->pcslen);
 		}
-	/*
-	 * NOTE: Causes for the error case  `up->pcslen > up->len':
-	 *        (i)  Application error (will not be penalized).
-	 *       (ii)  Payload too big for send buffer: data is split
-	 *             into several packets, each with its own header.
-	 *             In this case (e.g. last segment), coverage may
-	 *             exceed packet length.
-	 *       Since packets with coverage length > packet length are
-	 *       illegal, we fall back to the defaults here.
-	 */
+		/*
+		 * NOTE: Causes for the error case  `up->pcslen > up->len':
+		 *        (i)  Application error (will not be penalized).
+		 *       (ii)  Payload too big for send buffer: data is split
+		 *             into several packets, each with its own header.
+		 *             In this case (e.g. last segment), coverage may
+		 *             exceed packet length.
+		 *       Since packets with coverage length > packet length are
+		 *       illegal, we fall back to the defaults here.
+		 */
 	}
-	return cscov;
-}
-
-static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
-{
-	int cscov = udplite_sender_cscov(udp_sk(sk), udp_hdr(skb));
-	__wsum csum = 0;
 
 	skb->ip_summed = CHECKSUM_NONE;     /* no HW support for checksumming */
 
@@ -115,7 +109,24 @@ static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
 	return csum;
 }
 
-extern void	udplite4_register(void);
-extern int 	udplite_get_port(struct sock *sk, unsigned short snum,
-			int (*scmp)(const struct sock *, const struct sock *));
+/* Fast-path computation of checksum. Socket may not be locked. */
+static inline __wsum udplite_csum(struct sk_buff *skb)
+{
+	const struct udp_sock *up = udp_sk(skb->sk);
+	const int off = skb_transport_offset(skb);
+	int len = skb->len - off;
+
+	if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
+		if (0 < up->pcslen)
+			len = up->pcslen;
+		udp_hdr(skb)->len = htons(up->pcslen);
+	}
+	skb->ip_summed = CHECKSUM_NONE;     /* no HW support for checksumming */
+
+	return skb_checksum(skb, off, len, 0);
+}
+
+void udplite4_register(void);
+int udplite_get_port(struct sock *sk, unsigned short snum,
+		     int (*scmp)(const struct sock *, const struct sock *));
 #endif	/* _UDPLITE_H */