[NET]: hard_header reservation.

1. Fix bad reservation in xfrm_state_check_space()
2. Macroize formula for reservation, use the macro over all the places
   in IP.

include/linux/netdevice.h

@@ -90,6 +90,11 @@ struct vlan_group;
 #define MAX_HEADER (LL_MAX_HEADER + 48)
 #endif
 
+/* Reserve 16byte aligned hard_header_len, but at least 16.
+ * Alternative is: dev->hard_header_len ? (dev->hard_header_len + 15)&~15 : 0
+ */
+#define LL_RESERVED_SPACE(dev) (((dev)->hard_header_len&~15) + 16)
+
 /*
  *	Network device statistics. Akin to the 2.0 ether stats but
  *	with byte counters.

net/ipv4/arp.c

@@ -510,11 +510,11 @@ void arp_send(int type, int ptype, u32 dest_ip,
 	 */
 	
 	skb = alloc_skb(sizeof(struct arphdr)+ 2*(dev->addr_len+4)
-				+ dev->hard_header_len + 15, GFP_ATOMIC);
+				+ LL_RESERVED_SPACE(dev), GFP_ATOMIC);
 	if (skb == NULL)
 		return;
 
-	skb_reserve(skb, (dev->hard_header_len+15)&~15);
+	skb_reserve(skb, LL_RESERVED_SPACE(dev));
 	skb->nh.raw = skb->data;
 	arp = (struct arphdr *) skb_put(skb,sizeof(struct arphdr) + 2*(dev->addr_len+4));
 	skb->dev = dev;

net/ipv4/igmp.c

@@ -211,7 +211,7 @@ static int igmp_send_report(struct net_device *dev, u32 group, int type)
 		return -1;
 	}
 
-	skb=alloc_skb(IGMP_SIZE+dev->hard_header_len+15, GFP_ATOMIC);
+	skb=alloc_skb(IGMP_SIZE+LL_RESERVED_SPACE(dev), GFP_ATOMIC);
 	if (skb == NULL) {
 		ip_rt_put(rt);
 		return -1;
@@ -219,7 +219,7 @@ static int igmp_send_report(struct net_device *dev, u32 group, int type)
 
 	skb->dst = &rt->u.dst;
 
-	skb_reserve(skb, (dev->hard_header_len+15)&~15);
+	skb_reserve(skb, LL_RESERVED_SPACE(dev));
 
 	skb->nh.iph = iph = (struct iphdr *)skb_put(skb, sizeof(struct iphdr)+4);
 

net/ipv4/ip_forward.c

@@ -92,7 +92,7 @@ int ip_forward(struct sk_buff *skb)
 		goto sr_failed;
 
 	/* We are about to mangle packet. Copy it! */
-	if (skb_cow(skb, rt->u.dst.dev->hard_header_len+rt->u.dst.header_len))
+	if (skb_cow(skb, LL_RESERVED_SPACE(rt->u.dst.dev)+rt->u.dst.header_len))
 		goto drop;
 	iph = skb->nh.iph;
 

net/ipv4/ip_gre.c

@@ -824,7 +824,7 @@ static int ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	skb->h.raw = skb->nh.raw;
 
-	max_headroom = ((tdev->hard_header_len+15)&~15)+ gre_hlen;
+	max_headroom = LL_RESERVED_SPACE(tdev) + gre_hlen;
 
 	if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) {
 		struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);

net/ipv4/ip_output.c

@@ -162,13 +162,13 @@ static inline int ip_finish_output2(struct sk_buff *skb)
 	struct dst_entry *dst = skb->dst;
 	struct hh_cache *hh = dst->hh;
 	struct net_device *dev = dst->dev;
+	int hh_len = LL_RESERVED_SPACE(dev);
 
 	/* Be paranoid, rather than too clever. */
-	if (unlikely(skb_headroom(skb) < dev->hard_header_len
-		     && dev->hard_header)) {
+	if (unlikely(skb_headroom(skb) < hh_len && dev->hard_header)) {
 		struct sk_buff *skb2;
 
-		skb2 = skb_realloc_headroom(skb, (dev->hard_header_len&~15) + 16);
+		skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));
 		if (skb2 == NULL) {
 			kfree_skb(skb);
 			return -ENOMEM;
@@ -572,7 +572,7 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*))
 		 *	Allocate buffer.
 		 */
 
-		if ((skb2 = alloc_skb(len+hlen+rt->u.dst.dev->hard_header_len+16,GFP_ATOMIC)) == NULL) {
+		if ((skb2 = alloc_skb(len+hlen+LL_RESERVED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) {
 			NETDEBUG(printk(KERN_INFO "IP: frag: no memory for new fragment!\n"));
 			err = -ENOMEM;
 			goto fail;
@@ -583,7 +583,7 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*))
 		 */
 
 		ip_copy_metadata(skb2, skb);
-		skb_reserve(skb2, (rt->u.dst.dev->hard_header_len&~15)+16);
+		skb_reserve(skb2, LL_RESERVED_SPACE(rt->u.dst.dev));
 		skb_put(skb2, len + hlen);
 		skb2->nh.raw = skb2->data;
 		skb2->h.raw = skb2->data + hlen;
@@ -771,7 +771,7 @@ int ip_append_data(struct sock *sk,
 		exthdrlen = 0;
 		mtu = inet->cork.fragsize;
 	}
-	hh_len = (rt->u.dst.dev->hard_header_len&~15) + 16;
+	hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
 
 	fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
 	maxfraglen = ((mtu-fragheaderlen) & ~7) + fragheaderlen;
@@ -967,7 +967,7 @@ ssize_t	ip_append_page(struct sock *sk, struct page *page,
 	if (!(rt->u.dst.dev->features&NETIF_F_SG))
 		return -EOPNOTSUPP;
 
-	hh_len = (rt->u.dst.dev->hard_header_len&~15)+16;
+	hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
 	mtu = inet->cork.fragsize;
 
 	fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);

net/ipv4/ipconfig.c

@@ -656,7 +656,7 @@ static void __init ic_bootp_send_if(struct ic_device *d, unsigned long jiffies_d
 	struct net_device *dev = d->dev;
 	struct sk_buff *skb;
 	struct bootp_pkt *b;
-	int hh_len = (dev->hard_header_len + 15) & ~15;
+	int hh_len = LL_RESERVED_SPACE(dev);
 	struct iphdr *h;
 
 	/* Allocate packet */

net/ipv4/ipip.c

@@ -616,7 +616,7 @@ static int ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 	/*
 	 * Okay, now see if we can stuff it in the buffer as-is.
 	 */
-	max_headroom = (((tdev->hard_header_len+15)&~15)+sizeof(struct iphdr));
+	max_headroom = (LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr));
 
 	if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) {
 		struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);

net/ipv4/ipmr.c

@@ -1178,7 +1178,7 @@ static void ipmr_queue_xmit(struct sk_buff *skb, struct mfc_cache *c,
 		return;
 	}
 
-	encap += dev->hard_header_len;
+	encap += LL_RESERVED_SPACE(dev);
 
 	if (skb_headroom(skb) < encap || skb_cloned(skb) || !last)
 		skb2 = skb_realloc_headroom(skb, (encap + 15)&~15);

net/ipv4/raw.c

@@ -280,7 +280,7 @@ static int raw_send_hdrinc(struct sock *sk, void *from, int length,
 	if (flags&MSG_PROBE)
 		goto out;
 
-	hh_len = (rt->u.dst.dev->hard_header_len&~15) + 16;
+	hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
 
 	skb = sock_alloc_send_skb(sk, length+hh_len+15,
 				  flags&MSG_DONTWAIT, &err);

net/ipv4/xfrm_state.c

@@ -501,7 +501,7 @@ int xfrm_state_check_expire(struct xfrm_state *x)
 
 int xfrm_state_check_space(struct xfrm_state *x, struct sk_buff *skb)
 {
-	int nhead = x->props.header_len + skb->dst->dev->hard_header_len
+	int nhead = x->props.header_len + LL_RESERVED_SPACE(skb->dst->dev)
 		- skb_headroom(skb);
 
 	if (nhead > 0)

net/ipv6/sit.c

@@ -552,7 +552,7 @@ static int ipip6_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 	/*
 	 * Okay, now see if we can stuff it in the buffer as-is.
 	 */
-	max_headroom = (((tdev->hard_header_len+15)&~15)+sizeof(struct iphdr));
+	max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
 
 	if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) {
 		struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);