[ovs-dev] [PATCH 04/13] Upstream GRE: Add segmentation offload for GRE TAP device.

Pravin B Shelar pshelar at nicira.com
Thu Nov 22 15:56:41 UTC 2012


From: Pravin Shelar <pshelar at nicira.com>

Signed-off-by: Pravin B Shelar <pshelar at nicira.com>
---
 include/linux/skbuff.h |   12 +++++
 net/ipv4/af_inet.c     |    1 +
 net/ipv4/gre.c         |  120 ++++++++++++++++++++++++++++++++++++++++++++++--
 net/ipv4/ip_gre.c      |    7 +++
 net/ipv4/tcp.c         |    1 +
 net/ipv4/udp.c         |    3 +-
 net/ipv6/ip6_offload.c |    1 +
 net/ipv6/udp_offload.c |    3 +-
 8 files changed, 142 insertions(+), 6 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index f2af494..585aca7 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -307,6 +307,8 @@ enum {
 	SKB_GSO_TCPV6 = 1 << 4,
 
 	SKB_GSO_FCOE = 1 << 5,
+
+	SKB_GSO_GRE = 1 << 6,
 };
 
 #if BITS_PER_LONG > 32
@@ -787,6 +789,16 @@ static inline int skb_cloned(const struct sk_buff *skb)
 	       (atomic_read(&skb_shinfo(skb)->dataref) & SKB_DATAREF_MASK) != 1;
 }
 
+static inline int unclone_skb(struct sk_buff *skb, gfp_t pri)
+{
+	might_sleep_if(pri & __GFP_WAIT);
+
+	if (skb_cloned(skb))
+		return pskb_expand_head(skb, 0, 0, pri);
+
+	return 0;
+}
+
 /**
  *	skb_header_cloned - is the header a clone
  *	@skb: buffer to check
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 24b384b..9a3d5d2 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1306,6 +1306,7 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb,
 		       SKB_GSO_UDP |
 		       SKB_GSO_DODGY |
 		       SKB_GSO_TCP_ECN |
+		       SKB_GSO_GRE |
 		       0)))
 		goto out;
 
diff --git a/net/ipv4/gre.c b/net/ipv4/gre.c
index b837551..7568853 100644
--- a/net/ipv4/gre.c
+++ b/net/ipv4/gre.c
@@ -138,6 +138,14 @@ struct sk_buff *gre_build_header(struct sk_buff *skb,
 	skb->local_df = 1;
 	__ip_select_ident(ip_hdr(skb), dst, 0);
 
+	if (skb_is_gso(skb)) {
+		if (unlikely(unclone_skb(skb, GFP_ATOMIC))) {
+			kfree_skb(skb);
+			return NULL;
+		}
+		skb_shinfo(skb)->gso_type |= SKB_GSO_GRE;
+	}
+
 	return skb;
 }
 EXPORT_SYMBOL(gre_build_header);
@@ -331,6 +339,91 @@ static void ipgre_err_v0(struct sk_buff *skb, u32 info)
 	}
 }
 
+static int gre_header_len(struct gre_base_hdr *greh)
+{
+	int len = GRE_HEADER_SECTION;
+
+	if (greh->flags & GRE_KEY)
+		len += GRE_HEADER_SECTION;
+	if (greh->flags & GRE_CSUM)
+		len += GRE_HEADER_SECTION;
+
+	return len;
+}
+
+static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
+				       netdev_features_t features)
+{
+	struct sk_buff *segs = ERR_PTR(-EINVAL);
+	struct gre_base_hdr *greh;
+	unsigned char *mac = skb_mac_header(skb);
+	int mac_len = skb->mac_len;
+	int net_hlen = skb_network_header_len(skb);
+	int doffset;
+	int ghl;
+
+	if (unlikely(skb_shinfo(skb)->gso_type &
+				~(SKB_GSO_TCPV4 |
+					SKB_GSO_UDP |
+					SKB_GSO_DODGY |
+					SKB_GSO_TCP_ECN |
+					SKB_GSO_GRE |
+					0)))
+		goto out;
+
+	if (unlikely(!pskb_may_pull(skb, sizeof(*greh))))
+		goto out;
+
+	greh = (struct gre_base_hdr *)skb_transport_header(skb);
+	ghl = gre_header_len(greh);
+
+	if (unlikely(!pskb_may_pull(skb, ghl)))
+		goto out;
+
+	__skb_pull(skb, ghl);
+	skb_reset_mac_header(skb);
+	skb_set_network_header(skb, skb->mac_len);
+	doffset = skb_mac_header(skb) - mac;
+	/* segment inner packet. */
+	segs = skb_gso_segment(skb, 0);
+	if (!segs || IS_ERR(segs))
+		goto out;
+
+	skb = segs;
+	do {
+		unsigned char *smac;
+
+		skb_push(skb, doffset);
+
+		skb_reset_mac_header(skb);
+		skb_set_network_header(skb, mac_len);
+		skb_set_transport_header(skb,
+					 skb_network_offset(skb) + net_hlen);
+		smac = skb_mac_header(skb);
+		skb->mac_len = mac_len;
+		/* Copy entire outer header from original skb. */
+		memmove(smac, mac, doffset);
+
+		greh = (struct gre_base_hdr *)skb_transport_header(skb);
+		if (greh->flags & GRE_CSUM) {
+			__be32 *gre_csum = (__be32 *)(greh + 1);
+			*gre_csum = 0;
+			*(__sum16 *)gre_csum = csum_fold(skb_checksum(skb,
+						skb_transport_offset(skb),
+						skb->len - skb_transport_offset(skb),
+						0));
+		}
+	} while ((skb = skb->next));
+
+out:
+	return segs;
+}
+
+static int gre_gso_send_check(struct sk_buff *skb)
+{
+	return 0;
+}
+
 static const struct net_protocol net_gre_protocol = {
 	.handler     = gre_rcv,
 	.err_handler = gre_err,
@@ -342,28 +435,48 @@ static const struct gre_protocol ipgre_protocol = {
 	.err_handler = ipgre_err_v0,
 };
 
+static const struct net_offload gre_offload = {
+        .callbacks = {
+                .gso_send_check =       gre_gso_send_check,
+                .gso_segment    =       gre_gso_segment,
+        },
+};
+
 static int __init gre_init(void)
 {
 	pr_info("GRE over IPv4 demultiplexor driver\n");
 
 	if (inet_add_protocol(&net_gre_protocol, IPPROTO_GRE) < 0) {
 		pr_err("can't add protocol\n");
-		return -EAGAIN;
+		goto err;
 	}
 	rtnl_lock();
 	if (gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO) < 0) {
 		pr_info("%s: can't add ipgre handler\n", __func__);
 		rtnl_unlock();
-		inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
-		return -EAGAIN;
+		goto err_gre;
 	}
 	rtnl_unlock();
 
+	if (inet_add_offload(&gre_offload, IPPROTO_GRE)) {
+		pr_err("can't add protocol offload\n");
+		goto err_gso;
+	}
 	return 0;
+err_gso:
+	rtnl_lock();
+	gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
+	rtnl_unlock();
+
+err_gre:
+	inet_del_protocol(&net_gre_protocol, IPPROTO_GRE);
+err:
+	return -EAGAIN;
 }
 
 static void __exit gre_exit(void)
 {
+	inet_del_offload(&gre_offload, IPPROTO_GRE);
 	rtnl_lock();
 	if (gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO) < 0)
 		pr_info("%s: can't remove protocol\n", __func__);
@@ -378,4 +491,3 @@ module_exit(gre_exit);
 MODULE_DESCRIPTION("GRE over IPv4 demultiplexer driver");
 MODULE_AUTHOR("D. Kozlov (xeb at mail.ru)");
 MODULE_LICENSE("GPL");
-
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 829fe3d..6b4e57f 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -594,7 +594,14 @@ static int ipgre_tunnel_init(struct net_device *dev)
 
 static int ipgre_tap_init(struct net_device *dev)
 {
+	struct ip_tunnel *tunnel = netdev_priv(dev);
 	__gre_tunnel_init(dev);
+
+	if (!(tunnel->parms.o_flags & TUNNEL_SEQ)) {
+		dev->features           |= NETIF_F_TSO;
+		dev->hw_features        |= NETIF_F_TSO;
+	}
+
 	return ip_tunnel_init(dev);
 }
 
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index e6eace1..541f9b6 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3024,6 +3024,7 @@ struct sk_buff *tcp_tso_segment(struct sk_buff *skb,
 			       SKB_GSO_DODGY |
 			       SKB_GSO_TCP_ECN |
 			       SKB_GSO_TCPV6 |
+			       SKB_GSO_GRE |
 			       0) ||
 			     !(type & (SKB_GSO_TCPV4 | SKB_GSO_TCPV6))))
 			goto out;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 79c8dbe..c256008 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2279,7 +2279,8 @@ struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 		/* Packet is from an untrusted source, reset gso_segs. */
 		int type = skb_shinfo(skb)->gso_type;
 
-		if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
+		if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
+				      SKB_GSO_GRE) ||
 			     !(type & (SKB_GSO_UDP))))
 			goto out;
 
diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index f26f0da..8234c1d 100644
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -99,6 +99,7 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
 		     ~(SKB_GSO_UDP |
 		       SKB_GSO_DODGY |
 		       SKB_GSO_TCP_ECN |
+		       SKB_GSO_GRE |
 		       SKB_GSO_TCPV6 |
 		       0)))
 		goto out;
diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
index 0c8934a..cf05cf0 100644
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -56,7 +56,8 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
 		/* Packet is from an untrusted source, reset gso_segs. */
 		int type = skb_shinfo(skb)->gso_type;
 
-		if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
+		if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
+				      SKB_GSO_GRE) ||
 			     !(type & (SKB_GSO_UDP))))
 			goto out;
 
-- 
1.7.1




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