1 files changed, 176 insertions, 20 deletions

diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index e5d436188464..f1d32280cb54 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -11,6 +11,7 @@
  */
 
 #include <linux/skbuff.h>
+#include <linux/init.h>
 #include <net/protocol.h>
 #include <net/gre.h>
 
@@ -26,8 +27,9 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
 {
 	struct sk_buff *segs = ERR_PTR(-EINVAL);
 	netdev_features_t enc_features;
-	int ghl = GRE_HEADER_SECTION;
+	int ghl;
 	struct gre_base_hdr *greh;
+	u16 mac_offset = skb->mac_header;
 	int mac_len = skb->mac_len;
 	__be16 protocol = skb->protocol;
 	int tnl_hlen;
@@ -48,23 +50,19 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
 
 	greh = (struct gre_base_hdr *)skb_transport_header(skb);
 
-	if (greh->flags & GRE_KEY)
-		ghl += GRE_HEADER_SECTION;
-	if (greh->flags & GRE_SEQ)
-		ghl += GRE_HEADER_SECTION;
-	if (greh->flags & GRE_CSUM) {
-		ghl += GRE_HEADER_SECTION;
-		csum = true;
-	} else
-		csum = false;
+	ghl = skb_inner_network_header(skb) - skb_transport_header(skb);
+	if (unlikely(ghl < sizeof(*greh)))
+		goto out;
 
-	/* setup inner skb. */
-	skb->protocol = greh->protocol;
-	skb->encapsulation = 0;
+	csum = !!(greh->flags & GRE_CSUM);
 
 	if (unlikely(!pskb_may_pull(skb, ghl)))
 		goto out;
 
+	/* setup inner skb. */
+	skb->protocol = greh->protocol;
+	skb->encapsulation = 0;
+
 	__skb_pull(skb, ghl);
 	skb_reset_mac_header(skb);
 	skb_set_network_header(skb, skb_inner_network_offset(skb));
@@ -73,8 +71,10 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
 	/* segment inner packet. */
 	enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
 	segs = skb_mac_gso_segment(skb, enc_features);
-	if (!segs || IS_ERR(segs))
+	if (!segs || IS_ERR(segs)) {
+		skb_gso_error_unwind(skb, protocol, ghl, mac_offset, mac_len);
 		goto out;
+	}
 
 	skb = segs;
 	tnl_hlen = skb_tnl_header_len(skb);
@@ -113,19 +113,175 @@ out:
 	return segs;
 }
 
+/* Compute the whole skb csum in s/w and store it, then verify GRO csum
+ * starting from gro_offset.
+ */
+static __sum16 gro_skb_checksum(struct sk_buff *skb)
+{
+	__sum16 sum;
+
+	skb->csum = skb_checksum(skb, 0, skb->len, 0);
+	NAPI_GRO_CB(skb)->csum = csum_sub(skb->csum,
+		csum_partial(skb->data, skb_gro_offset(skb), 0));
+	sum = csum_fold(NAPI_GRO_CB(skb)->csum);
+	if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE)) {
+		if (unlikely(!sum))
+			netdev_rx_csum_fault(skb->dev);
+	} else
+		skb->ip_summed = CHECKSUM_COMPLETE;
+
+	return sum;
+}
+
+static struct sk_buff **gre_gro_receive(struct sk_buff **head,
+					struct sk_buff *skb)
+{
+	struct sk_buff **pp = NULL;
+	struct sk_buff *p;
+	const struct gre_base_hdr *greh;
+	unsigned int hlen, grehlen;
+	unsigned int off;
+	int flush = 1;
+	struct packet_offload *ptype;
+	__be16 type;
+
+	off = skb_gro_offset(skb);
+	hlen = off + sizeof(*greh);
+	greh = skb_gro_header_fast(skb, off);
+	if (skb_gro_header_hard(skb, hlen)) {
+		greh = skb_gro_header_slow(skb, hlen, off);
+		if (unlikely(!greh))
+			goto out;
+	}
+
+	/* Only support version 0 and K (key), C (csum) flags. Note that
+	 * although the support for the S (seq#) flag can be added easily
+	 * for GRO, this is problematic for GSO hence can not be enabled
+	 * here because a GRO pkt may end up in the forwarding path, thus
+	 * requiring GSO support to break it up correctly.
+	 */
+	if ((greh->flags & ~(GRE_KEY|GRE_CSUM)) != 0)
+		goto out;
+
+	type = greh->protocol;
+
+	rcu_read_lock();
+	ptype = gro_find_receive_by_type(type);
+	if (ptype == NULL)
+		goto out_unlock;
+
+	grehlen = GRE_HEADER_SECTION;
+
+	if (greh->flags & GRE_KEY)
+		grehlen += GRE_HEADER_SECTION;
+
+	if (greh->flags & GRE_CSUM)
+		grehlen += GRE_HEADER_SECTION;
+
+	hlen = off + grehlen;
+	if (skb_gro_header_hard(skb, hlen)) {
+		greh = skb_gro_header_slow(skb, hlen, off);
+		if (unlikely(!greh))
+			goto out_unlock;
+	}
+	if (greh->flags & GRE_CSUM) { /* Need to verify GRE csum first */
+		__sum16 csum = 0;
+
+		if (skb->ip_summed == CHECKSUM_COMPLETE)
+			csum = csum_fold(NAPI_GRO_CB(skb)->csum);
+		/* Don't trust csum error calculated/reported by h/w */
+		if (skb->ip_summed == CHECKSUM_NONE || csum != 0)
+			csum = gro_skb_checksum(skb);
+
+		/* GRE CSUM is the 1's complement of the 1's complement sum
+		 * of the GRE hdr plus payload so it should add up to 0xffff
+		 * (and 0 after csum_fold()) just like the IPv4 hdr csum.
+		 */
+		if (csum)
+			goto out_unlock;
+	}
+	flush = 0;
+
+	for (p = *head; p; p = p->next) {
+		const struct gre_base_hdr *greh2;
+
+		if (!NAPI_GRO_CB(p)->same_flow)
+			continue;
+
+		/* The following checks are needed to ensure only pkts
+		 * from the same tunnel are considered for aggregation.
+		 * The criteria for "the same tunnel" includes:
+		 * 1) same version (we only support version 0 here)
+		 * 2) same protocol (we only support ETH_P_IP for now)
+		 * 3) same set of flags
+		 * 4) same key if the key field is present.
+		 */
+		greh2 = (struct gre_base_hdr *)(p->data + off);
+
+		if (greh2->flags != greh->flags ||
+		    greh2->protocol != greh->protocol) {
+			NAPI_GRO_CB(p)->same_flow = 0;
+			continue;
+		}
+		if (greh->flags & GRE_KEY) {
+			/* compare keys */
+			if (*(__be32 *)(greh2+1) != *(__be32 *)(greh+1)) {
+				NAPI_GRO_CB(p)->same_flow = 0;
+				continue;
+			}
+		}
+	}
+
+	skb_gro_pull(skb, grehlen);
+
+	/* Adjusted NAPI_GRO_CB(skb)->csum after skb_gro_pull()*/
+	skb_gro_postpull_rcsum(skb, greh, grehlen);
+
+	pp = ptype->callbacks.gro_receive(head, skb);
+
+out_unlock:
+	rcu_read_unlock();
+out:
+	NAPI_GRO_CB(skb)->flush |= flush;
+
+	return pp;
+}
+
+static int gre_gro_complete(struct sk_buff *skb, int nhoff)
+{
+	struct gre_base_hdr *greh = (struct gre_base_hdr *)(skb->data + nhoff);
+	struct packet_offload *ptype;
+	unsigned int grehlen = sizeof(*greh);
+	int err = -ENOENT;
+	__be16 type;
+
+	type = greh->protocol;
+	if (greh->flags & GRE_KEY)
+		grehlen += GRE_HEADER_SECTION;
+
+	if (greh->flags & GRE_CSUM)
+		grehlen += GRE_HEADER_SECTION;
+
+	rcu_read_lock();
+	ptype = gro_find_complete_by_type(type);
+	if (ptype != NULL)
+		err = ptype->callbacks.gro_complete(skb, nhoff + grehlen);
+
+	rcu_read_unlock();
+	return err;
+}
+
 static const struct net_offload gre_offload = {
 	.callbacks = {
 		.gso_send_check = gre_gso_send_check,
 		.gso_segment = gre_gso_segment,
+		.gro_receive = gre_gro_receive,
+		.gro_complete = gre_gro_complete,
 	},
 };
 
-int __init gre_offload_init(void)
+static int __init gre_offload_init(void)
 {
 	return inet_add_offload(&gre_offload, IPPROTO_GRE);
 }
-
-void __exit gre_offload_exit(void)
-{
-	inet_del_offload(&gre_offload, IPPROTO_GRE);
-}
+device_initcall(gre_offload_init);