[UDP]: Allow users to configure UDP-Lite.

Let's give users an option for disabling UDP-Lite (~4K).

old:
|    text	   data	    bss	    dec	    hex	filename
|  286498	  12432	   6072	 305002	  4a76a	net/ipv4/built-in.o
|  193830	   8192	   3204	 205226	  321aa	net/ipv6/ipv6.o

new (without UDP-Lite):
|    text	   data	    bss	    dec	    hex	filename
|  284086	  12136	   5432	 301654	  49a56	net/ipv4/built-in.o
|  191835	   7832	   3076	 202743	  317f7	net/ipv6/ipv6.o

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

4 files changed, 28 insertions, 2 deletions

diff --git a/include/linux/udp.h b/include/linux/udp.h
index 8ec703f..4144664 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -70,8 +70,10 @@ struct udp_sock {
 #define UDPLITE_BIT      0x1  		/* set by udplite proto init function */
 #define UDPLITE_SEND_CC  0x2  		/* set via udplite setsockopt         */
 #define UDPLITE_RECV_CC  0x4		/* set via udplite setsocktopt        */
+#ifdef CONFIG_IP_UDPLITE
 	__u8		 pcflag;        /* marks socket as UDP-Lite if > 0    */
 	__u8		 unused[3];
+#endif
 	/*
 	 * For encapsulation sockets.
 	 */
@@ -82,7 +84,16 @@ static inline struct udp_sock *udp_sk(const struct sock *sk)
 {
 	return (struct udp_sock *)sk;
 }
+
+#ifdef CONFIG_IP_UDPLITE
 #define IS_UDPLITE(__sk) (udp_sk(__sk)->pcflag)
+#define IS_PROTO_UDPLITE(__proto) ((__proto) == IPPROTO_UDPLITE)
+#define IS_SOL_UDPFAMILY(level) ((level) == SOL_UDP || (level) == SOL_UDPLITE)
+#else
+#define IS_UDPLITE(__sk) 0
+#define IS_PROTO_UDPLITE(__proto) 0
+#define IS_SOL_UDPFAMILY(level) ((level) == SOL_UDP)
+#endif
 
 #endif
 
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 8b05c65..96b1763 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -603,8 +603,13 @@ extern int  tcp6_proc_init(void);
 extern void tcp6_proc_exit(void);
 extern int  udp6_proc_init(void);
 extern void udp6_proc_exit(void);
+#ifdef CONFIG_IP_UDPLITE
 extern int  udplite6_proc_init(void);
 extern void udplite6_proc_exit(void);
+#else
+static inline int udplite6_proc_init(void) { return 0; }
+static inline void udplite6_proc_exit(void) { }
+#endif
 extern int  ipv6_misc_proc_init(void);
 extern void ipv6_misc_proc_exit(void);
 extern int snmp6_register_dev(struct inet6_dev *idev);
diff --git a/include/net/transp_v6.h b/include/net/transp_v6.h
index 27394e0..902e6c6 100644
--- a/include/net/transp_v6.h
+++ b/include/net/transp_v6.h
@@ -27,8 +27,13 @@ extern int				rawv6_init(void);
 extern void				rawv6_exit(void);
 extern int				udpv6_init(void);
 extern void				udpv6_exit(void);
+#ifdef CONFIG_IP_UDPLITE
 extern int 				udplitev6_init(void);
 extern void 				udplitev6_exit(void);
+#else
+static inline int udplitev6_init(void) { return 0; }
+static inline void udplitev6_exit(void) { }
+#endif
 extern int				tcpv6_init(void);
 extern void				tcpv6_exit(void);
 
diff --git a/include/net/udplite.h b/include/net/udplite.h
index b76b2e3..01ddb2c 100644
--- a/include/net/udplite.h
+++ b/include/net/udplite.h
@@ -25,7 +25,9 @@ static __inline__ int udplite_getfrag(void *from, char *to, int  offset,
 /* Designate sk as UDP-Lite socket */
 static inline int udplite_sk_init(struct sock *sk)
 {
+#ifdef CONFIG_IP_UDPLITE
 	udp_sk(sk)->pcflag = UDPLITE_BIT;
+#endif
 	return 0;
 }
 
@@ -69,7 +71,7 @@ static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
 static inline int udplite_sender_cscov(struct udp_sock *up, struct udphdr *uh)
 {
 	int cscov = up->len;
-
+#ifdef CONFIG_IP_UDPLITE
 	/*
 	 * Sender has set `partial coverage' option on UDP-Lite socket
 	 */
@@ -93,13 +95,15 @@ static inline int udplite_sender_cscov(struct udp_sock *up, struct udphdr *uh)
 	 *       illegal, we fall back to the defaults here.
 	 */
 	}
+#endif
 	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;
+#ifdef CONFIG_IP_UDPLITE
+	int cscov = udplite_sender_cscov(udp_sk(sk), udp_hdr(skb));
 
 	skb->ip_summed = CHECKSUM_NONE;     /* no HW support for checksumming */
 
@@ -112,6 +116,7 @@ static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
 		if ((cscov -= len) <= 0)
 			break;
 	}
+#endif
 	return csum;
 }