netdev - [PATCH RFC 3/3] udp: Support UDP fraglist GRO/GSO.

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Message-ID: <20181221075334.9000-4-steffen.klassert@secunet.com>
Date:   Fri, 21 Dec 2018 08:53:34 +0100
From:   Steffen Klassert <steffen.klassert@...unet.com>
To:     <netdev@...r.kernel.org>
CC:     Steffen Klassert <steffen.klassert@...unet.com>,
        Willem de Bruijn <willemb@...gle.com>,
        Paolo Abeni <pabeni@...hat.com>,
        "Jason A. Donenfeld" <Jason@...c4.com>
Subject: [PATCH RFC 3/3] udp: Support UDP fraglist GRO/GSO.

This patch extends UDP GRO to support fraglist GRO/GSO
by using the previously introduced infrastructure.
All UDP packets that are not targeted to a GRO capable
UDP sockets are going to fraglist GRO now (local input
and forward).

Signed-off-by: Steffen Klassert <steffen.klassert@...unet.com>
---
 net/ipv4/udp_offload.c | 57 ++++++++++++++++++++++++++++++++++++------
 1 file changed, 49 insertions(+), 8 deletions(-)

diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 0646d61f4fa8..9d77cc44da6b 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -187,6 +187,20 @@ struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 }
 EXPORT_SYMBOL(skb_udp_tunnel_segment);
 
+static struct sk_buff *__udp_gso_segment_list(struct sk_buff *skb,
+					      netdev_features_t features)
+{
+	unsigned int mss = skb_shinfo(skb)->gso_size;
+
+	skb = skb_segment_list(skb, features, skb_mac_header_len(skb));
+	if (IS_ERR(skb))
+		return skb;
+
+	udp_hdr(skb)->len = htons(sizeof(struct udphdr) + mss);
+
+	return skb;
+}
+
 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
 				  netdev_features_t features)
 {
@@ -199,6 +213,9 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
 	__sum16 check;
 	__be16 newlen;
 
+	if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)
+		return __udp_gso_segment_list(gso_skb, features);
+
 	mss = skb_shinfo(gso_skb)->gso_size;
 	if (gso_skb->len <= sizeof(*uh) + mss)
 		return ERR_PTR(-EINVAL);
@@ -351,16 +368,15 @@ static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
 	struct sk_buff *pp = NULL;
 	struct udphdr *uh2;
 	struct sk_buff *p;
+	int ret;
 
 	/* requires non zero csum, for symmetry with GSO */
 	if (!uh->check) {
 		NAPI_GRO_CB(skb)->flush = 1;
 		return NULL;
 	}
-
 	/* pull encapsulating udp header */
 	skb_gro_pull(skb, sizeof(struct udphdr));
-	skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
 
 	list_for_each_entry(p, head, list) {
 		if (!NAPI_GRO_CB(p)->same_flow)
@@ -378,8 +394,17 @@ static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
 		 * Under small packet flood GRO count could elsewhere grow a lot
 		 * leading to execessive truesize values
 		 */
-		if (!skb_gro_receive(p, skb) &&
-		    NAPI_GRO_CB(p)->count >= UDP_GRO_CNT_MAX)
+		if (NAPI_GRO_CB(skb)->is_flist) {
+			if (!pskb_may_pull(skb, skb_gro_offset(skb)))
+				return NULL;
+			ret = skb_gro_receive_list(p, skb);
+		} else {
+			skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
+
+			ret = skb_gro_receive(p, skb);
+		}
+
+		if (!ret && NAPI_GRO_CB(p)->count > UDP_GRO_CNT_MAX)
 			pp = p;
 		else if (uh->len != uh2->len)
 			pp = p;
@@ -403,10 +428,17 @@ struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
 
 	rcu_read_lock();
 	sk = (*lookup)(skb, uh->source, uh->dest);
-	if (!sk)
-		goto out_unlock;
+	if (!sk) {
+		NAPI_GRO_CB(skb)->is_flist = 1;
+		pp = call_gro_receive(udp_gro_receive_segment, head, skb);
+		rcu_read_unlock();
+		return pp;
+	}
+
+	if (!udp_sk(sk)->gro_receive) {
+		if (!udp_sk(sk)->gro_enabled)
+			NAPI_GRO_CB(skb)->is_flist = 1;
 
-	if (udp_sk(sk)->gro_enabled) {
 		pp = call_gro_receive(udp_gro_receive_segment, head, skb);
 		rcu_read_unlock();
 		return pp;
@@ -456,7 +488,7 @@ static struct sk_buff *udp4_gro_receive(struct list_head *head,
 {
 	struct udphdr *uh = udp_gro_udphdr(skb);
 
-	if (unlikely(!uh) || !static_branch_unlikely(&udp_encap_needed_key))
+	if (unlikely(!uh))
 		goto flush;
 
 	/* Don't bother verifying checksum if we're going to flush anyway. */
@@ -530,6 +562,15 @@ static int udp4_gro_complete(struct sk_buff *skb, int nhoff)
 	const struct iphdr *iph = ip_hdr(skb);
 	struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
 
+	if (NAPI_GRO_CB(skb)->is_flist) {
+		uh->len = htons(skb->len - nhoff);
+
+		skb_shinfo(skb)->gso_type |= (SKB_GSO_FRAGLIST|SKB_GSO_UDP_L4);
+		skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
+
+		return 0;
+	}
+
 	if (uh->check)
 		uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
 					  iph->daddr, 0);
-- 
2.17.1