diff --git a/Documentation/networking/netdev-features.txt b/Documentation/networking/netdev-features.txt
index c77f9d57eb91584878d26061450c3e08a5b19030..c4a54c162547d3e290a69446afadef54aac7f1d5 100644
--- a/Documentation/networking/netdev-features.txt
+++ b/Documentation/networking/netdev-features.txt
@@ -113,6 +113,13 @@ whatever headers there might be.
 NETIF_F_TSO_ECN means that hardware can properly split packets with CWR bit
 set, be it TCPv4 (when NETIF_F_TSO is enabled) or TCPv6 (NETIF_F_TSO6).
 
+ * Transmit UDP segmentation offload
+
+NETIF_F_GSO_UDP_GSO_L4 accepts a single UDP header with a payload that exceeds
+gso_size. On segmentation, it segments the payload on gso_size boundaries and
+replicates the network and UDP headers (fixing up the last one if less than
+gso_size).
+
  * Transmit DMA from high memory
 
 On platforms where this is relevant, NETIF_F_HIGHDMA signals that
diff --git a/include/linux/netdev_features.h b/include/linux/netdev_features.h
index 35b79f47a13de3a6664fe6c8e79e75c4738f2fd7..fe2f3b30960ee381f8c1f598084d1bab76f37f0c 100644
--- a/include/linux/netdev_features.h
+++ b/include/linux/netdev_features.h
@@ -55,8 +55,9 @@ enum {
 	NETIF_F_GSO_SCTP_BIT,		/* ... SCTP fragmentation */
 	NETIF_F_GSO_ESP_BIT,		/* ... ESP with TSO */
 	NETIF_F_GSO_UDP_BIT,		/* ... UFO, deprecated except tuntap */
+	NETIF_F_GSO_UDP_L4_BIT,		/* ... UDP payload GSO (not UFO) */
 	/**/NETIF_F_GSO_LAST =		/* last bit, see GSO_MASK */
-		NETIF_F_GSO_UDP_BIT,
+		NETIF_F_GSO_UDP_L4_BIT,
 
 	NETIF_F_FCOE_CRC_BIT,		/* FCoE CRC32 */
 	NETIF_F_SCTP_CRC_BIT,		/* SCTP checksum offload */
@@ -147,6 +148,7 @@ enum {
 #define NETIF_F_HW_ESP_TX_CSUM	__NETIF_F(HW_ESP_TX_CSUM)
 #define	NETIF_F_RX_UDP_TUNNEL_PORT  __NETIF_F(RX_UDP_TUNNEL_PORT)
 #define NETIF_F_HW_TLS_RECORD	__NETIF_F(HW_TLS_RECORD)
+#define NETIF_F_GSO_UDP_L4	__NETIF_F(GSO_UDP_L4)
 
 #define for_each_netdev_feature(mask_addr, bit)	\
 	for_each_set_bit(bit, (unsigned long *)mask_addr, NETDEV_FEATURE_COUNT)
@@ -216,6 +218,7 @@ enum {
 				 NETIF_F_GSO_GRE_CSUM |			\
 				 NETIF_F_GSO_IPXIP4 |			\
 				 NETIF_F_GSO_IPXIP6 |			\
+				 NETIF_F_GSO_UDP_L4 |			\
 				 NETIF_F_GSO_UDP_TUNNEL |		\
 				 NETIF_F_GSO_UDP_TUNNEL_CSUM)
 
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 14e0777ffcfb0b2a501fe5ae5a1a70f5f8666d24..366c32891158dd1f27135b369835d3fcb165c22b 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -4186,6 +4186,7 @@ static inline bool net_gso_ok(netdev_features_t features, int gso_type)
 	BUILD_BUG_ON(SKB_GSO_SCTP    != (NETIF_F_GSO_SCTP >> NETIF_F_GSO_SHIFT));
 	BUILD_BUG_ON(SKB_GSO_ESP != (NETIF_F_GSO_ESP >> NETIF_F_GSO_SHIFT));
 	BUILD_BUG_ON(SKB_GSO_UDP != (NETIF_F_GSO_UDP >> NETIF_F_GSO_SHIFT));
+	BUILD_BUG_ON(SKB_GSO_UDP_L4 != (NETIF_F_GSO_UDP_L4 >> NETIF_F_GSO_SHIFT));
 
 	return (features & feature) == feature;
 }
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index d274059529eb5216d041dfdcad4a564a623c8ea0..a4a5c0c5cba89d1db792435cc230d774cfa6ad3f 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -573,6 +573,8 @@ enum {
 	SKB_GSO_ESP = 1 << 15,
 
 	SKB_GSO_UDP = 1 << 16,
+
+	SKB_GSO_UDP_L4 = 1 << 17,
 };
 
 #if BITS_PER_LONG > 32
diff --git a/include/linux/udp.h b/include/linux/udp.h
index eaea63bc79bb2418ebec58e1afa88129ecdc8ca7..ca840345571bf6cf9253647c11112252fa7b6241 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -55,6 +55,7 @@ struct udp_sock {
 	 * when the socket is uncorked.
 	 */
 	__u16		 len;		/* total length of pending frames */
+	__u16		 gso_size;
 	/*
 	 * Fields specific to UDP-Lite.
 	 */
@@ -87,6 +88,8 @@ struct udp_sock {
 	int		forward_deficit;
 };
 
+#define UDP_MAX_SEGMENTS	(1 << 6UL)
+
 static inline struct udp_sock *udp_sk(const struct sock *sk)
 {
 	return (struct udp_sock *)sk;
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 0a671c32d6b96008be5432cb94fa088bac210ae4..83d5b3c2ac421ca29e8ed654dcbf054379e3001b 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -147,6 +147,7 @@ struct inet_cork {
 	__u8			ttl;
 	__s16			tos;
 	char			priority;
+	__u16			gso_size;
 };
 
 struct inet_cork_full {
diff --git a/include/net/ip.h b/include/net/ip.h
index dc4a2d6e58a516a5ba8fe38ea3fe07522653da93..bada1f1f871e163b1c7d0434e5928242648cbfad 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -76,6 +76,7 @@ struct ipcm_cookie {
 	__u8			ttl;
 	__s16			tos;
 	char			priority;
+	__u16			gso_size;
 };
 
 #define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
@@ -171,7 +172,7 @@ struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
 					int len, int odd, struct sk_buff *skb),
 			    void *from, int length, int transhdrlen,
 			    struct ipcm_cookie *ipc, struct rtable **rtp,
-			    unsigned int flags);
+			    struct inet_cork *cork, unsigned int flags);
 
 static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
 {
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 68b167d988792f1278af3bdb808768bea23fe30c..0a872a7c33c86e2cbaa84be6800b3cf5b4a5dbdb 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -298,6 +298,7 @@ struct ipcm6_cookie {
 	__s16 tclass;
 	__s8  dontfrag;
 	struct ipv6_txoptions *opt;
+	__u16 gso_size;
 };
 
 static inline struct ipv6_txoptions *txopt_get(const struct ipv6_pinfo *np)
@@ -950,6 +951,7 @@ struct sk_buff *ip6_make_skb(struct sock *sk,
 			     void *from, int length, int transhdrlen,
 			     struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
 			     struct rt6_info *rt, unsigned int flags,
+			     struct inet_cork_full *cork,
 			     const struct sockcm_cookie *sockc);
 
 static inline struct sk_buff *ip6_finish_skb(struct sock *sk)
diff --git a/include/net/udp.h b/include/net/udp.h
index 0676b272f6ac8bf91d07f18b7f75e39481a47eaa..05990746810eaae7802426ca9527d5fe4dddd995 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -174,6 +174,10 @@ struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb,
 				 struct udphdr *uh, udp_lookup_t lookup);
 int udp_gro_complete(struct sk_buff *skb, int nhoff, udp_lookup_t lookup);
 
+struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
+				  netdev_features_t features,
+				  unsigned int mss, __sum16 check);
+
 static inline struct udphdr *udp_gro_udphdr(struct sk_buff *skb)
 {
 	struct udphdr *uh;
@@ -269,6 +273,7 @@ int udp_abort(struct sock *sk, int err);
 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
 int udp_push_pending_frames(struct sock *sk);
 void udp_flush_pending_frames(struct sock *sk);
+int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
 int udp_rcv(struct sk_buff *skb);
 int udp_ioctl(struct sock *sk, int cmd, unsigned long arg);
diff --git a/include/uapi/linux/udp.h b/include/uapi/linux/udp.h
index efb7b5991c2fd5eaeab64ca0a52074d9f6cd9a11..09d00f8c442b785d98c097b38fcdde25f8e967ef 100644
--- a/include/uapi/linux/udp.h
+++ b/include/uapi/linux/udp.h
@@ -32,6 +32,7 @@ struct udphdr {
 #define UDP_ENCAP	100	/* Set the socket to accept encapsulated packets */
 #define UDP_NO_CHECK6_TX 101	/* Disable sending checksum for UDP6X */
 #define UDP_NO_CHECK6_RX 102	/* Disable accpeting checksum for UDP6 */
+#define UDP_SEGMENT	103	/* Set GSO segmentation size */
 
 /* UDP encapsulation types */
 #define UDP_ENCAP_ESPINUDP_NON_IKE	1 /* draft-ietf-ipsec-nat-t-ike-00/01 */
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 03416e6dd5d7b0c2bb4dbfc805832e4fb67fba92..4650fd6d678cebb5b41e2d3034ad0fd14dc3f073 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -92,6 +92,7 @@ static const char netdev_features_strings[NETDEV_FEATURE_COUNT][ETH_GSTRING_LEN]
 	[NETIF_F_GSO_PARTIAL_BIT] =	 "tx-gso-partial",
 	[NETIF_F_GSO_SCTP_BIT] =	 "tx-sctp-segmentation",
 	[NETIF_F_GSO_ESP_BIT] =		 "tx-esp-segmentation",
+	[NETIF_F_GSO_UDP_L4_BIT] =	 "tx-udp-segmentation",
 
 	[NETIF_F_FCOE_CRC_BIT] =         "tx-checksum-fcoe-crc",
 	[NETIF_F_SCTP_CRC_BIT] =        "tx-checksum-sctp",
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index ff49e352deea1d07049f5c5ac425fbcdb4fd96a8..c647cfe114e02e537a39c2d124634fafaa2251e5 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4940,6 +4940,8 @@ static unsigned int skb_gso_transport_seglen(const struct sk_buff *skb)
 		thlen = tcp_hdrlen(skb);
 	} else if (unlikely(skb_is_gso_sctp(skb))) {
 		thlen = sizeof(struct sctphdr);
+	} else if (shinfo->gso_type & SKB_GSO_UDP_L4) {
+		thlen = sizeof(struct udphdr);
 	}
 	/* UFO sets gso_size to the size of the fragmentation
 	 * payload, i.e. the size of the L4 (UDP) header is already
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 83c73bab2c3de90254e11e4126d7cb77ed998f03..f2338e40c37d9512fc53310dd1c6b323cba6ea41 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -878,11 +878,14 @@ static int __ip_append_data(struct sock *sk,
 	struct rtable *rt = (struct rtable *)cork->dst;
 	unsigned int wmem_alloc_delta = 0;
 	u32 tskey = 0;
+	bool paged;
 
 	skb = skb_peek_tail(queue);
 
 	exthdrlen = !skb ? rt->dst.header_len : 0;
-	mtu = cork->fragsize;
+	mtu = cork->gso_size ? IP_MAX_MTU : cork->fragsize;
+	paged = !!cork->gso_size;
+
 	if (cork->tx_flags & SKBTX_ANY_SW_TSTAMP &&
 	    sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
 		tskey = sk->sk_tskey++;
@@ -906,7 +909,7 @@ static int __ip_append_data(struct sock *sk,
 	if (transhdrlen &&
 	    length + fragheaderlen <= mtu &&
 	    rt->dst.dev->features & (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM) &&
-	    !(flags & MSG_MORE) &&
+	    (!(flags & MSG_MORE) || cork->gso_size) &&
 	    !exthdrlen)
 		csummode = CHECKSUM_PARTIAL;
 
@@ -933,6 +936,7 @@ static int __ip_append_data(struct sock *sk,
 			unsigned int fraglen;
 			unsigned int fraggap;
 			unsigned int alloclen;
+			unsigned int pagedlen = 0;
 			struct sk_buff *skb_prev;
 alloc_new_skb:
 			skb_prev = skb;
@@ -953,8 +957,12 @@ static int __ip_append_data(struct sock *sk,
 			if ((flags & MSG_MORE) &&
 			    !(rt->dst.dev->features&NETIF_F_SG))
 				alloclen = mtu;
-			else
+			else if (!paged)
 				alloclen = fraglen;
+			else {
+				alloclen = min_t(int, fraglen, MAX_HEADER);
+				pagedlen = fraglen - alloclen;
+			}
 
 			alloclen += exthdrlen;
 
@@ -998,7 +1006,7 @@ static int __ip_append_data(struct sock *sk,
 			/*
 			 *	Find where to start putting bytes.
 			 */
-			data = skb_put(skb, fraglen + exthdrlen);
+			data = skb_put(skb, fraglen + exthdrlen - pagedlen);
 			skb_set_network_header(skb, exthdrlen);
 			skb->transport_header = (skb->network_header +
 						 fragheaderlen);
@@ -1014,7 +1022,7 @@ static int __ip_append_data(struct sock *sk,
 				pskb_trim_unique(skb_prev, maxfraglen);
 			}
 
-			copy = datalen - transhdrlen - fraggap;
+			copy = datalen - transhdrlen - fraggap - pagedlen;
 			if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
 				err = -EFAULT;
 				kfree_skb(skb);
@@ -1022,7 +1030,7 @@ static int __ip_append_data(struct sock *sk,
 			}
 
 			offset += copy;
-			length -= datalen - fraggap;
+			length -= copy + transhdrlen;
 			transhdrlen = 0;
 			exthdrlen = 0;
 			csummode = CHECKSUM_NONE;
@@ -1135,6 +1143,8 @@ static int ip_setup_cork(struct sock *sk, struct inet_cork *cork,
 	*rtp = NULL;
 	cork->fragsize = ip_sk_use_pmtu(sk) ?
 			 dst_mtu(&rt->dst) : rt->dst.dev->mtu;
+
+	cork->gso_size = sk->sk_type == SOCK_DGRAM ? ipc->gso_size : 0;
 	cork->dst = &rt->dst;
 	cork->length = 0;
 	cork->ttl = ipc->ttl;
@@ -1214,7 +1224,7 @@ ssize_t	ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
 		return -EOPNOTSUPP;
 
 	hh_len = LL_RESERVED_SPACE(rt->dst.dev);
-	mtu = cork->fragsize;
+	mtu = cork->gso_size ? IP_MAX_MTU : cork->fragsize;
 
 	fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
 	maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
@@ -1470,9 +1480,8 @@ struct sk_buff *ip_make_skb(struct sock *sk,
 					int len, int odd, struct sk_buff *skb),
 			    void *from, int length, int transhdrlen,
 			    struct ipcm_cookie *ipc, struct rtable **rtp,
-			    unsigned int flags)
+			    struct inet_cork *cork, unsigned int flags)
 {
-	struct inet_cork cork;
 	struct sk_buff_head queue;
 	int err;
 
@@ -1481,22 +1490,22 @@ struct sk_buff *ip_make_skb(struct sock *sk,
 
 	__skb_queue_head_init(&queue);
 
-	cork.flags = 0;
-	cork.addr = 0;
-	cork.opt = NULL;
-	err = ip_setup_cork(sk, &cork, ipc, rtp);
+	cork->flags = 0;
+	cork->addr = 0;
+	cork->opt = NULL;
+	err = ip_setup_cork(sk, cork, ipc, rtp);
 	if (err)
 		return ERR_PTR(err);
 
-	err = __ip_append_data(sk, fl4, &queue, &cork,
+	err = __ip_append_data(sk, fl4, &queue, cork,
 			       &current->task_frag, getfrag,
 			       from, length, transhdrlen, flags);
 	if (err) {
-		__ip_flush_pending_frames(sk, &queue, &cork);
+		__ip_flush_pending_frames(sk, &queue, cork);
 		return ERR_PTR(err);
 	}
 
-	return __ip_make_skb(sk, fl4, &queue, &cork);
+	return __ip_make_skb(sk, fl4, &queue, cork);
 }
 
 /*
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 24b5c59b1c533a9793042c134f23891953527752..794aeafeb782d17ca865b3f902f591a257bdc868 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -757,7 +757,8 @@ void udp_set_csum(bool nocheck, struct sk_buff *skb,
 }
 EXPORT_SYMBOL(udp_set_csum);
 
-static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
+static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4,
+			struct inet_cork *cork)
 {
 	struct sock *sk = skb->sk;
 	struct inet_sock *inet = inet_sk(sk);
@@ -777,6 +778,21 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
 	uh->len = htons(len);
 	uh->check = 0;
 
+	if (cork->gso_size) {
+		const int hlen = skb_network_header_len(skb) +
+				 sizeof(struct udphdr);
+
+		if (hlen + cork->gso_size > cork->fragsize)
+			return -EINVAL;
+		if (skb->len > cork->gso_size * UDP_MAX_SEGMENTS)
+			return -EINVAL;
+		if (skb->ip_summed != CHECKSUM_PARTIAL || is_udplite)
+			return -EIO;
+
+		skb_shinfo(skb)->gso_size = cork->gso_size;
+		skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4;
+	}
+
 	if (is_udplite)  				 /*     UDP-Lite      */
 		csum = udplite_csum(skb);
 
@@ -828,7 +844,7 @@ int udp_push_pending_frames(struct sock *sk)
 	if (!skb)
 		goto out;
 
-	err = udp_send_skb(skb, fl4);
+	err = udp_send_skb(skb, fl4, &inet->cork.base);
 
 out:
 	up->len = 0;
@@ -837,6 +853,43 @@ int udp_push_pending_frames(struct sock *sk)
 }
 EXPORT_SYMBOL(udp_push_pending_frames);
 
+static int __udp_cmsg_send(struct cmsghdr *cmsg, u16 *gso_size)
+{
+	switch (cmsg->cmsg_type) {
+	case UDP_SEGMENT:
+		if (cmsg->cmsg_len != CMSG_LEN(sizeof(__u16)))
+			return -EINVAL;
+		*gso_size = *(__u16 *)CMSG_DATA(cmsg);
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size)
+{
+	struct cmsghdr *cmsg;
+	bool need_ip = false;
+	int err;
+
+	for_each_cmsghdr(cmsg, msg) {
+		if (!CMSG_OK(msg, cmsg))
+			return -EINVAL;
+
+		if (cmsg->cmsg_level != SOL_UDP) {
+			need_ip = true;
+			continue;
+		}
+
+		err = __udp_cmsg_send(cmsg, gso_size);
+		if (err)
+			return err;
+	}
+
+	return need_ip;
+}
+EXPORT_SYMBOL_GPL(udp_cmsg_send);
+
 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 {
 	struct inet_sock *inet = inet_sk(sk);
@@ -922,10 +975,14 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	ipc.sockc.tsflags = sk->sk_tsflags;
 	ipc.addr = inet->inet_saddr;
 	ipc.oif = sk->sk_bound_dev_if;
+	ipc.gso_size = up->gso_size;
 
 	if (msg->msg_controllen) {
-		err = ip_cmsg_send(sk, msg, &ipc, sk->sk_family == AF_INET6);
-		if (unlikely(err)) {
+		err = udp_cmsg_send(sk, msg, &ipc.gso_size);
+		if (err > 0)
+			err = ip_cmsg_send(sk, msg, &ipc,
+					   sk->sk_family == AF_INET6);
+		if (unlikely(err < 0)) {
 			kfree(ipc.opt);
 			return err;
 		}
@@ -1030,12 +1087,14 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
 	/* Lockless fast path for the non-corking case. */
 	if (!corkreq) {
+		struct inet_cork cork;
+
 		skb = ip_make_skb(sk, fl4, getfrag, msg, ulen,
 				  sizeof(struct udphdr), &ipc, &rt,
-				  msg->msg_flags);
+				  &cork, msg->msg_flags);
 		err = PTR_ERR(skb);
 		if (!IS_ERR_OR_NULL(skb))
-			err = udp_send_skb(skb, fl4);
+			err = udp_send_skb(skb, fl4, &cork);
 		goto out;
 	}
 
@@ -2365,6 +2424,12 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
 		up->no_check6_rx = valbool;
 		break;
 
+	case UDP_SEGMENT:
+		if (val < 0 || val > USHRT_MAX)
+			return -EINVAL;
+		up->gso_size = val;
+		break;
+
 	/*
 	 * 	UDP-Lite's partial checksum coverage (RFC 3828).
 	 */
@@ -2455,6 +2520,10 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname,
 		val = up->no_check6_rx;
 		break;
 
+	case UDP_SEGMENT:
+		val = up->gso_size;
+		break;
+
 	/* The following two cannot be changed on UDP sockets, the return is
 	 * always 0 (which corresponds to the full checksum coverage of UDP). */
 	case UDPLITE_SEND_CSCOV:
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index ea6e6e7df0eec8e79f631851846cf6957014c162..dc5158cba66e38213eb068f572cacf2abb10f9af 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -187,6 +187,68 @@ struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
 }
 EXPORT_SYMBOL(skb_udp_tunnel_segment);
 
+struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
+				  netdev_features_t features,
+				  unsigned int mss, __sum16 check)
+{
+	struct sock *sk = gso_skb->sk;
+	unsigned int sum_truesize = 0;
+	struct sk_buff *segs, *seg;
+	unsigned int hdrlen;
+	struct udphdr *uh;
+
+	if (gso_skb->len <= sizeof(*uh) + mss)
+		return ERR_PTR(-EINVAL);
+
+	hdrlen = gso_skb->data - skb_mac_header(gso_skb);
+	skb_pull(gso_skb, sizeof(*uh));
+
+	/* clear destructor to avoid skb_segment assigning it to tail */
+	WARN_ON_ONCE(gso_skb->destructor != sock_wfree);
+	gso_skb->destructor = NULL;
+
+	segs = skb_segment(gso_skb, features);
+	if (unlikely(IS_ERR_OR_NULL(segs))) {
+		gso_skb->destructor = sock_wfree;
+		return segs;
+	}
+
+	for (seg = segs; seg; seg = seg->next) {
+		uh = udp_hdr(seg);
+		uh->len = htons(seg->len - hdrlen);
+		uh->check = check;
+
+		/* last packet can be partial gso_size */
+		if (!seg->next)
+			csum_replace2(&uh->check, htons(mss),
+				      htons(seg->len - hdrlen - sizeof(*uh)));
+
+		seg->destructor = sock_wfree;
+		seg->sk = sk;
+		sum_truesize += seg->truesize;
+	}
+
+	refcount_add(sum_truesize - gso_skb->truesize, &sk->sk_wmem_alloc);
+
+	return segs;
+}
+EXPORT_SYMBOL_GPL(__udp_gso_segment);
+
+static struct sk_buff *__udp4_gso_segment(struct sk_buff *gso_skb,
+					  netdev_features_t features)
+{
+	const struct iphdr *iph = ip_hdr(gso_skb);
+	unsigned int mss = skb_shinfo(gso_skb)->gso_size;
+
+	if (!can_checksum_protocol(features, htons(ETH_P_IP)))
+		return ERR_PTR(-EIO);
+
+	return __udp_gso_segment(gso_skb, features, mss,
+				 udp_v4_check(sizeof(struct udphdr) + mss,
+					      iph->saddr, iph->daddr, 0));
+}
+EXPORT_SYMBOL_GPL(__udp4_gso_segment);
+
 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 					 netdev_features_t features)
 {
@@ -203,12 +265,15 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
 		goto out;
 	}
 
-	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP))
+	if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
 		goto out;
 
 	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
 		goto out;
 
+	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
+		return __udp4_gso_segment(skb, features);
+
 	mss = skb_shinfo(skb)->gso_size;
 	if (unlikely(skb->len <= mss))
 		goto out;
diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index 4a87f9428ca519b475f8feaceaaa3a225bcfe6d2..5b3f2f89ef41c3276ef4b478683bd9ab04a1d3da 100644
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -88,9 +88,11 @@ static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb,
 
 	if (skb->encapsulation &&
 	    skb_shinfo(skb)->gso_type & (SKB_GSO_IPXIP4 | SKB_GSO_IPXIP6))
-		udpfrag = proto == IPPROTO_UDP && encap;
+		udpfrag = proto == IPPROTO_UDP && encap &&
+			  (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
 	else
-		udpfrag = proto == IPPROTO_UDP && !skb->encapsulation;
+		udpfrag = proto == IPPROTO_UDP && !skb->encapsulation &&
+			  (skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
 
 	ops = rcu_dereference(inet6_offloads[proto]);
 	if (likely(ops && ops->callbacks.gso_segment)) {
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 6a477d54f8c72e5b502c202c7af0a04a552ee26e..dfd8af41824ead16e28e6c3736d34ca2e9bae820 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1240,6 +1240,8 @@ static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
 	if (mtu < IPV6_MIN_MTU)
 		return -EINVAL;
 	cork->base.fragsize = mtu;
+	cork->base.gso_size = sk->sk_type == SOCK_DGRAM ? ipc6->gso_size : 0;
+
 	if (dst_allfrag(xfrm_dst_path(&rt->dst)))
 		cork->base.flags |= IPCORK_ALLFRAG;
 	cork->base.length = 0;
@@ -1274,6 +1276,7 @@ static int __ip6_append_data(struct sock *sk,
 	int csummode = CHECKSUM_NONE;
 	unsigned int maxnonfragsize, headersize;
 	unsigned int wmem_alloc_delta = 0;
+	bool paged;
 
 	skb = skb_peek_tail(queue);
 	if (!skb) {
@@ -1281,7 +1284,8 @@ static int __ip6_append_data(struct sock *sk,
 		dst_exthdrlen = rt->dst.header_len - rt->rt6i_nfheader_len;
 	}
 
-	mtu = cork->fragsize;
+	paged = !!cork->gso_size;
+	mtu = cork->gso_size ? IP6_MAX_MTU : cork->fragsize;
 	orig_mtu = mtu;
 
 	hh_len = LL_RESERVED_SPACE(rt->dst.dev);
@@ -1329,7 +1333,7 @@ static int __ip6_append_data(struct sock *sk,
 	if (transhdrlen && sk->sk_protocol == IPPROTO_UDP &&
 	    headersize == sizeof(struct ipv6hdr) &&
 	    length <= mtu - headersize &&
-	    !(flags & MSG_MORE) &&
+	    (!(flags & MSG_MORE) || cork->gso_size) &&
 	    rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM))
 		csummode = CHECKSUM_PARTIAL;
 
@@ -1372,6 +1376,7 @@ static int __ip6_append_data(struct sock *sk,
 			unsigned int fraglen;
 			unsigned int fraggap;
 			unsigned int alloclen;
+			unsigned int pagedlen = 0;
 alloc_new_skb:
 			/* There's no room in the current skb */
 			if (skb)
@@ -1394,11 +1399,17 @@ static int __ip6_append_data(struct sock *sk,
 
 			if (datalen > (cork->length <= mtu && !(cork->flags & IPCORK_ALLFRAG) ? mtu : maxfraglen) - fragheaderlen)
 				datalen = maxfraglen - fragheaderlen - rt->dst.trailer_len;
+			fraglen = datalen + fragheaderlen;
+
 			if ((flags & MSG_MORE) &&
 			    !(rt->dst.dev->features&NETIF_F_SG))
 				alloclen = mtu;
-			else
-				alloclen = datalen + fragheaderlen;
+			else if (!paged)
+				alloclen = fraglen;
+			else {
+				alloclen = min_t(int, fraglen, MAX_HEADER);
+				pagedlen = fraglen - alloclen;
+			}
 
 			alloclen += dst_exthdrlen;
 
@@ -1420,7 +1431,7 @@ static int __ip6_append_data(struct sock *sk,
 			 */
 			alloclen += sizeof(struct frag_hdr);
 
-			copy = datalen - transhdrlen - fraggap;
+			copy = datalen - transhdrlen - fraggap - pagedlen;
 			if (copy < 0) {
 				err = -EINVAL;
 				goto error;
@@ -1459,7 +1470,7 @@ static int __ip6_append_data(struct sock *sk,
 			/*
 			 *	Find where to start putting bytes
 			 */
-			data = skb_put(skb, fraglen);
+			data = skb_put(skb, fraglen - pagedlen);
 			skb_set_network_header(skb, exthdrlen);
 			data += fragheaderlen;
 			skb->transport_header = (skb->network_header +
@@ -1482,7 +1493,7 @@ static int __ip6_append_data(struct sock *sk,
 			}
 
 			offset += copy;
-			length -= datalen - fraggap;
+			length -= copy + transhdrlen;
 			transhdrlen = 0;
 			exthdrlen = 0;
 			dst_exthdrlen = 0;
@@ -1755,9 +1766,9 @@ struct sk_buff *ip6_make_skb(struct sock *sk,
 			     void *from, int length, int transhdrlen,
 			     struct ipcm6_cookie *ipc6, struct flowi6 *fl6,
 			     struct rt6_info *rt, unsigned int flags,
+			     struct inet_cork_full *cork,
 			     const struct sockcm_cookie *sockc)
 {
-	struct inet_cork_full cork;
 	struct inet6_cork v6_cork;
 	struct sk_buff_head queue;
 	int exthdrlen = (ipc6->opt ? ipc6->opt->opt_flen : 0);
@@ -1768,27 +1779,27 @@ struct sk_buff *ip6_make_skb(struct sock *sk,
 
 	__skb_queue_head_init(&queue);
 
-	cork.base.flags = 0;
-	cork.base.addr = 0;
-	cork.base.opt = NULL;
-	cork.base.dst = NULL;
+	cork->base.flags = 0;
+	cork->base.addr = 0;
+	cork->base.opt = NULL;
+	cork->base.dst = NULL;
 	v6_cork.opt = NULL;
-	err = ip6_setup_cork(sk, &cork, &v6_cork, ipc6, rt, fl6);
+	err = ip6_setup_cork(sk, cork, &v6_cork, ipc6, rt, fl6);
 	if (err) {
-		ip6_cork_release(&cork, &v6_cork);
+		ip6_cork_release(cork, &v6_cork);
 		return ERR_PTR(err);
 	}
 	if (ipc6->dontfrag < 0)
 		ipc6->dontfrag = inet6_sk(sk)->dontfrag;
 
-	err = __ip6_append_data(sk, fl6, &queue, &cork.base, &v6_cork,
+	err = __ip6_append_data(sk, fl6, &queue, &cork->base, &v6_cork,
 				&current->task_frag, getfrag, from,
 				length + exthdrlen, transhdrlen + exthdrlen,
 				flags, ipc6, sockc);
 	if (err) {
-		__ip6_flush_pending_frames(sk, &queue, &cork, &v6_cork);
+		__ip6_flush_pending_frames(sk, &queue, cork, &v6_cork);
 		return ERR_PTR(err);
 	}
 
-	return __ip6_make_skb(sk, &queue, &cork, &v6_cork);
+	return __ip6_make_skb(sk, &queue, cork, &v6_cork);
 }
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 4ec76a87aeb869050022d71c8095d840526cef70..6acfdd3e442b6a9a865e122c04555ad94d6af5b4 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1023,7 +1023,8 @@ static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
  *	Sending
  */
 
-static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6)
+static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6,
+			   struct inet_cork *cork)
 {
 	struct sock *sk = skb->sk;
 	struct udphdr *uh;
@@ -1042,6 +1043,21 @@ static int udp_v6_send_skb(struct sk_buff *skb, struct flowi6 *fl6)
 	uh->len = htons(len);
 	uh->check = 0;
 
+	if (cork->gso_size) {
+		const int hlen = skb_network_header_len(skb) +
+				 sizeof(struct udphdr);
+
+		if (hlen + cork->gso_size > cork->fragsize)
+			return -EINVAL;
+		if (skb->len > cork->gso_size * UDP_MAX_SEGMENTS)
+			return -EINVAL;
+		if (skb->ip_summed != CHECKSUM_PARTIAL || is_udplite)
+			return -EIO;
+
+		skb_shinfo(skb)->gso_size = cork->gso_size;
+		skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4;
+	}
+
 	if (is_udplite)
 		csum = udplite_csum(skb);
 	else if (udp_sk(sk)->no_check6_tx) {   /* UDP csum disabled */
@@ -1093,7 +1109,7 @@ static int udp_v6_push_pending_frames(struct sock *sk)
 	if (!skb)
 		goto out;
 
-	err = udp_v6_send_skb(skb, &fl6);
+	err = udp_v6_send_skb(skb, &fl6, &inet_sk(sk)->cork.base);
 
 out:
 	up->len = 0;
@@ -1127,6 +1143,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	ipc6.hlimit = -1;
 	ipc6.tclass = -1;
 	ipc6.dontfrag = -1;
+	ipc6.gso_size = up->gso_size;
 	sockc.tsflags = sk->sk_tsflags;
 
 	/* destination address check */
@@ -1259,7 +1276,10 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		opt->tot_len = sizeof(*opt);
 		ipc6.opt = opt;
 
-		err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6, &ipc6, &sockc);
+		err = udp_cmsg_send(sk, msg, &ipc6.gso_size);
+		if (err > 0)
+			err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, &fl6,
+						    &ipc6, &sockc);
 		if (err < 0) {
 			fl6_sock_release(flowlabel);
 			return err;
@@ -1324,15 +1344,16 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
 	/* Lockless fast path for the non-corking case */
 	if (!corkreq) {
+		struct inet_cork_full cork;
 		struct sk_buff *skb;
 
 		skb = ip6_make_skb(sk, getfrag, msg, ulen,
 				   sizeof(struct udphdr), &ipc6,
 				   &fl6, (struct rt6_info *)dst,
-				   msg->msg_flags, &sockc);
+				   msg->msg_flags, &cork, &sockc);
 		err = PTR_ERR(skb);
 		if (!IS_ERR_OR_NULL(skb))
-			err = udp_v6_send_skb(skb, &fl6);
+			err = udp_v6_send_skb(skb, &fl6, &cork.base);
 		goto out;
 	}
 
diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
index 2a04dc9c781b5f236fbe6dc3804f5eeed174ee44..f7b85b1e6b3e6d06bbeafd6ecfed025ef71143d7 100644
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -17,6 +17,20 @@
 #include <net/ip6_checksum.h>
 #include "ip6_offload.h"
 
+static struct sk_buff *__udp6_gso_segment(struct sk_buff *gso_skb,
+					  netdev_features_t features)
+{
+	const struct ipv6hdr *ip6h = ipv6_hdr(gso_skb);
+	unsigned int mss = skb_shinfo(gso_skb)->gso_size;
+
+	if (!can_checksum_protocol(features, htons(ETH_P_IPV6)))
+		return ERR_PTR(-EIO);
+
+	return __udp_gso_segment(gso_skb, features, mss,
+				 udp_v6_check(sizeof(struct udphdr) + mss,
+					      &ip6h->saddr, &ip6h->daddr, 0));
+}
+
 static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
 					 netdev_features_t features)
 {
@@ -42,12 +56,15 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
 		const struct ipv6hdr *ipv6h;
 		struct udphdr *uh;
 
-		if (!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP))
+		if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4)))
 			goto out;
 
 		if (!pskb_may_pull(skb, sizeof(struct udphdr)))
 			goto out;
 
+		if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
+			return __udp6_gso_segment(skb, features);
+
 		/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
 		 * do checksum of UDP packets sent as multiple IP fragments.
 		 */
diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore
index 5559f6add04680522bede6f9073cc961bec5b1d6..f0e6c35a93ae941c6494f2df80f8034dc46528c9 100644
--- a/tools/testing/selftests/net/.gitignore
+++ b/tools/testing/selftests/net/.gitignore
@@ -8,3 +8,6 @@ reuseport_bpf_numa
 reuseport_dualstack
 reuseaddr_conflict
 tcp_mmap
+udpgso
+udpgso_bench_rx
+udpgso_bench_tx
diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index c3761c35f542ea78f8113ebd5c41740c86904e6a..df9102ec7b7af4b707a9a28c3f077d7a473f6067 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -5,12 +5,14 @@ CFLAGS =  -Wall -Wl,--no-as-needed -O2 -g
 CFLAGS += -I../../../../usr/include/
 
 TEST_PROGS := run_netsocktests run_afpackettests test_bpf.sh netdevice.sh rtnetlink.sh
-TEST_PROGS += fib_tests.sh fib-onlink-tests.sh in_netns.sh pmtu.sh
+TEST_PROGS += fib_tests.sh fib-onlink-tests.sh in_netns.sh pmtu.sh udpgso.sh
+TEST_PROGS += udpgso_bench.sh
 TEST_GEN_FILES =  socket
 TEST_GEN_FILES += psock_fanout psock_tpacket msg_zerocopy
 TEST_GEN_FILES += tcp_mmap
 TEST_GEN_PROGS = reuseport_bpf reuseport_bpf_cpu reuseport_bpf_numa
 TEST_GEN_PROGS += reuseport_dualstack reuseaddr_conflict
+TEST_GEN_PROGS += udpgso udpgso_bench_tx udpgso_bench_rx
 
 include ../lib.mk
 
diff --git a/tools/testing/selftests/net/udpgso.c b/tools/testing/selftests/net/udpgso.c
new file mode 100644
index 0000000000000000000000000000000000000000..48a0592db938f3897e23a2e81fa260118f3064d4
--- /dev/null
+++ b/tools/testing/selftests/net/udpgso.c
@@ -0,0 +1,620 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+
+#include <stddef.h>
+#include <arpa/inet.h>
+#include <error.h>
+#include <errno.h>
+#include <net/if.h>
+#include <linux/in.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <netinet/if_ether.h>
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <netinet/udp.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#ifndef ETH_MAX_MTU
+#define ETH_MAX_MTU	0xFFFFU
+#endif
+
+#ifndef UDP_SEGMENT
+#define UDP_SEGMENT		103
+#endif
+
+#define CONST_MTU_TEST	1500
+
+#define CONST_HDRLEN_V4		(sizeof(struct iphdr) + sizeof(struct udphdr))
+#define CONST_HDRLEN_V6		(sizeof(struct ip6_hdr) + sizeof(struct udphdr))
+
+#define CONST_MSS_V4		(CONST_MTU_TEST - CONST_HDRLEN_V4)
+#define CONST_MSS_V6		(CONST_MTU_TEST - CONST_HDRLEN_V6)
+
+#define CONST_MAX_SEGS_V4	(ETH_MAX_MTU / CONST_MSS_V4)
+#define CONST_MAX_SEGS_V6	(ETH_MAX_MTU / CONST_MSS_V6)
+
+static bool		cfg_do_ipv4;
+static bool		cfg_do_ipv6;
+static bool		cfg_do_connected;
+static bool		cfg_do_connectionless;
+static bool		cfg_do_msgmore;
+static bool		cfg_do_setsockopt;
+static int		cfg_specific_test_id = -1;
+
+static const char	cfg_ifname[] = "lo";
+static unsigned short	cfg_port = 9000;
+
+static char buf[ETH_MAX_MTU];
+
+struct testcase {
+	int tlen;		/* send() buffer size, may exceed mss */
+	bool tfail;		/* send() call is expected to fail */
+	int gso_len;		/* mss after applying gso */
+	int r_num_mss;		/* recv(): number of calls of full mss */
+	int r_len_last;		/* recv(): size of last non-mss dgram, if any */
+};
+
+const struct in6_addr addr6 = IN6ADDR_LOOPBACK_INIT;
+const struct in_addr addr4 = { .s_addr = __constant_htonl(INADDR_LOOPBACK + 2) };
+
+struct testcase testcases_v4[] = {
+	{
+		/* no GSO: send a single byte */
+		.tlen = 1,
+		.r_len_last = 1,
+	},
+	{
+		/* no GSO: send a single MSS */
+		.tlen = CONST_MSS_V4,
+		.r_num_mss = 1,
+	},
+	{
+		/* no GSO: send a single MSS + 1B: fail */
+		.tlen = CONST_MSS_V4 + 1,
+		.tfail = true,
+	},
+	{
+		/* send a single MSS: will fail with GSO, because the segment
+		 * logic in udp4_ufo_fragment demands a gso skb to be > MTU
+		 */
+		.tlen = CONST_MSS_V4,
+		.gso_len = CONST_MSS_V4,
+		.tfail = true,
+		.r_num_mss = 1,
+	},
+	{
+		/* send a single MSS + 1B */
+		.tlen = CONST_MSS_V4 + 1,
+		.gso_len = CONST_MSS_V4,
+		.r_num_mss = 1,
+		.r_len_last = 1,
+	},
+	{
+		/* send exactly 2 MSS */
+		.tlen = CONST_MSS_V4 * 2,
+		.gso_len = CONST_MSS_V4,
+		.r_num_mss = 2,
+	},
+	{
+		/* send 2 MSS + 1B */
+		.tlen = (CONST_MSS_V4 * 2) + 1,
+		.gso_len = CONST_MSS_V4,
+		.r_num_mss = 2,
+		.r_len_last = 1,
+	},
+	{
+		/* send MAX segs */
+		.tlen = (ETH_MAX_MTU / CONST_MSS_V4) * CONST_MSS_V4,
+		.gso_len = CONST_MSS_V4,
+		.r_num_mss = (ETH_MAX_MTU / CONST_MSS_V4),
+	},
+
+	{
+		/* send MAX bytes */
+		.tlen = ETH_MAX_MTU - CONST_HDRLEN_V4,
+		.gso_len = CONST_MSS_V4,
+		.r_num_mss = CONST_MAX_SEGS_V4,
+		.r_len_last = ETH_MAX_MTU - CONST_HDRLEN_V4 -
+			      (CONST_MAX_SEGS_V4 * CONST_MSS_V4),
+	},
+	{
+		/* send MAX + 1: fail */
+		.tlen = ETH_MAX_MTU - CONST_HDRLEN_V4 + 1,
+		.gso_len = CONST_MSS_V4,
+		.tfail = true,
+	},
+	{
+		/* EOL */
+	}
+};
+
+#ifndef IP6_MAX_MTU
+#define IP6_MAX_MTU	(ETH_MAX_MTU + sizeof(struct ip6_hdr))
+#endif
+
+struct testcase testcases_v6[] = {
+	{
+		/* no GSO: send a single byte */
+		.tlen = 1,
+		.r_len_last = 1,
+	},
+	{
+		/* no GSO: send a single MSS */
+		.tlen = CONST_MSS_V6,
+		.r_num_mss = 1,
+	},
+	{
+		/* no GSO: send a single MSS + 1B: fail */
+		.tlen = CONST_MSS_V6 + 1,
+		.tfail = true,
+	},
+	{
+		/* send a single MSS: will fail with GSO, because the segment
+		 * logic in udp4_ufo_fragment demands a gso skb to be > MTU
+		 */
+		.tlen = CONST_MSS_V6,
+		.gso_len = CONST_MSS_V6,
+		.tfail = true,
+		.r_num_mss = 1,
+	},
+	{
+		/* send a single MSS + 1B */
+		.tlen = CONST_MSS_V6 + 1,
+		.gso_len = CONST_MSS_V6,
+		.r_num_mss = 1,
+		.r_len_last = 1,
+	},
+	{
+		/* send exactly 2 MSS */
+		.tlen = CONST_MSS_V6 * 2,
+		.gso_len = CONST_MSS_V6,
+		.r_num_mss = 2,
+	},
+	{
+		/* send 2 MSS + 1B */
+		.tlen = (CONST_MSS_V6 * 2) + 1,
+		.gso_len = CONST_MSS_V6,
+		.r_num_mss = 2,
+		.r_len_last = 1,
+	},
+	{
+		/* send MAX segs */
+		.tlen = (IP6_MAX_MTU / CONST_MSS_V6) * CONST_MSS_V6,
+		.gso_len = CONST_MSS_V6,
+		.r_num_mss = (IP6_MAX_MTU / CONST_MSS_V6),
+	},
+
+	{
+		/* send MAX bytes */
+		.tlen = IP6_MAX_MTU - CONST_HDRLEN_V6,
+		.gso_len = CONST_MSS_V6,
+		.r_num_mss = CONST_MAX_SEGS_V6,
+		.r_len_last = IP6_MAX_MTU - CONST_HDRLEN_V6 -
+			      (CONST_MAX_SEGS_V6 * CONST_MSS_V6),
+	},
+	{
+		/* send MAX + 1: fail */
+		.tlen = IP6_MAX_MTU - CONST_HDRLEN_V6 + 1,
+		.gso_len = CONST_MSS_V6,
+		.tfail = true,
+	},
+	{
+		/* EOL */
+	}
+};
+
+static unsigned int get_device_mtu(int fd, const char *ifname)
+{
+	struct ifreq ifr;
+
+	memset(&ifr, 0, sizeof(ifr));
+
+	strcpy(ifr.ifr_name, ifname);
+
+	if (ioctl(fd, SIOCGIFMTU, &ifr))
+		error(1, errno, "ioctl get mtu");
+
+	return ifr.ifr_mtu;
+}
+
+static void __set_device_mtu(int fd, const char *ifname, unsigned int mtu)
+{
+	struct ifreq ifr;
+
+	memset(&ifr, 0, sizeof(ifr));
+
+	ifr.ifr_mtu = mtu;
+	strcpy(ifr.ifr_name, ifname);
+
+	if (ioctl(fd, SIOCSIFMTU, &ifr))
+		error(1, errno, "ioctl set mtu");
+}
+
+static void set_device_mtu(int fd, int mtu)
+{
+	int val;
+
+	val = get_device_mtu(fd, cfg_ifname);
+	fprintf(stderr, "device mtu (orig): %u\n", val);
+
+	__set_device_mtu(fd, cfg_ifname, mtu);
+	val = get_device_mtu(fd, cfg_ifname);
+	if (val != mtu)
+		error(1, 0, "unable to set device mtu to %u\n", val);
+
+	fprintf(stderr, "device mtu (test): %u\n", val);
+}
+
+static void set_pmtu_discover(int fd, bool is_ipv4)
+{
+	int level, name, val;
+
+	if (is_ipv4) {
+		level	= SOL_IP;
+		name	= IP_MTU_DISCOVER;
+		val	= IP_PMTUDISC_DO;
+	} else {
+		level	= SOL_IPV6;
+		name	= IPV6_MTU_DISCOVER;
+		val	= IPV6_PMTUDISC_DO;
+	}
+
+	if (setsockopt(fd, level, name, &val, sizeof(val)))
+		error(1, errno, "setsockopt path mtu");
+}
+
+static unsigned int get_path_mtu(int fd, bool is_ipv4)
+{
+	socklen_t vallen;
+	unsigned int mtu;
+	int ret;
+
+	vallen = sizeof(mtu);
+	if (is_ipv4)
+		ret = getsockopt(fd, SOL_IP, IP_MTU, &mtu, &vallen);
+	else
+		ret = getsockopt(fd, SOL_IPV6, IPV6_MTU, &mtu, &vallen);
+
+	if (ret)
+		error(1, errno, "getsockopt mtu");
+
+
+	fprintf(stderr, "path mtu (read):  %u\n", mtu);
+	return mtu;
+}
+
+/* very wordy version of system("ip route add dev lo mtu 1500 127.0.0.3/32") */
+static void set_route_mtu(int mtu, bool is_ipv4)
+{
+	struct sockaddr_nl nladdr = { .nl_family = AF_NETLINK };
+	struct nlmsghdr *nh;
+	struct rtattr *rta;
+	struct rtmsg *rt;
+	char data[NLMSG_ALIGN(sizeof(*nh)) +
+		  NLMSG_ALIGN(sizeof(*rt)) +
+		  NLMSG_ALIGN(RTA_LENGTH(sizeof(addr6))) +
+		  NLMSG_ALIGN(RTA_LENGTH(sizeof(int))) +
+		  NLMSG_ALIGN(RTA_LENGTH(0) + RTA_LENGTH(sizeof(int)))];
+	int fd, ret, alen, off = 0;
+
+	alen = is_ipv4 ? sizeof(addr4) : sizeof(addr6);
+
+	fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+	if (fd == -1)
+		error(1, errno, "socket netlink");
+
+	memset(data, 0, sizeof(data));
+
+	nh = (void *)data;
+	nh->nlmsg_type = RTM_NEWROUTE;
+	nh->nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE;
+	off += NLMSG_ALIGN(sizeof(*nh));
+
+	rt = (void *)(data + off);
+	rt->rtm_family = is_ipv4 ? AF_INET : AF_INET6;
+	rt->rtm_table = RT_TABLE_MAIN;
+	rt->rtm_dst_len = alen << 3;
+	rt->rtm_protocol = RTPROT_BOOT;
+	rt->rtm_scope = RT_SCOPE_UNIVERSE;
+	rt->rtm_type = RTN_UNICAST;
+	off += NLMSG_ALIGN(sizeof(*rt));
+
+	rta = (void *)(data + off);
+	rta->rta_type = RTA_DST;
+	rta->rta_len = RTA_LENGTH(alen);
+	if (is_ipv4)
+		memcpy(RTA_DATA(rta), &addr4, alen);
+	else
+		memcpy(RTA_DATA(rta), &addr6, alen);
+	off += NLMSG_ALIGN(rta->rta_len);
+
+	rta = (void *)(data + off);
+	rta->rta_type = RTA_OIF;
+	rta->rta_len = RTA_LENGTH(sizeof(int));
+	*((int *)(RTA_DATA(rta))) = 1; //if_nametoindex("lo");
+	off += NLMSG_ALIGN(rta->rta_len);
+
+	/* MTU is a subtype in a metrics type */
+	rta = (void *)(data + off);
+	rta->rta_type = RTA_METRICS;
+	rta->rta_len = RTA_LENGTH(0) + RTA_LENGTH(sizeof(int));
+	off += NLMSG_ALIGN(rta->rta_len);
+
+	/* now fill MTU subtype. Note that it fits within above rta_len */
+	rta = (void *)(((char *) rta) + RTA_LENGTH(0));
+	rta->rta_type = RTAX_MTU;
+	rta->rta_len = RTA_LENGTH(sizeof(int));
+	*((int *)(RTA_DATA(rta))) = mtu;
+
+	nh->nlmsg_len = off;
+
+	ret = sendto(fd, data, off, 0, (void *)&nladdr, sizeof(nladdr));
+	if (ret != off)
+		error(1, errno, "send netlink: %uB != %uB\n", ret, off);
+
+	if (close(fd))
+		error(1, errno, "close netlink");
+
+	fprintf(stderr, "route mtu (test): %u\n", mtu);
+}
+
+static bool __send_one(int fd, struct msghdr *msg, int flags)
+{
+	int ret;
+
+	ret = sendmsg(fd, msg, flags);
+	if (ret == -1 && (errno == EMSGSIZE || errno == ENOMEM))
+		return false;
+	if (ret == -1)
+		error(1, errno, "sendmsg");
+	if (ret != msg->msg_iov->iov_len)
+		error(1, 0, "sendto: %d != %lu", ret, msg->msg_iov->iov_len);
+	if (msg->msg_flags)
+		error(1, 0, "sendmsg: return flags 0x%x\n", msg->msg_flags);
+
+	return true;
+}
+
+static bool send_one(int fd, int len, int gso_len,
+		     struct sockaddr *addr, socklen_t alen)
+{
+	char control[CMSG_SPACE(sizeof(uint16_t))] = {0};
+	struct msghdr msg = {0};
+	struct iovec iov = {0};
+	struct cmsghdr *cm;
+
+	iov.iov_base = buf;
+	iov.iov_len = len;
+
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+
+	msg.msg_name = addr;
+	msg.msg_namelen = alen;
+
+	if (gso_len && !cfg_do_setsockopt) {
+		msg.msg_control = control;
+		msg.msg_controllen = sizeof(control);
+
+		cm = CMSG_FIRSTHDR(&msg);
+		cm->cmsg_level = SOL_UDP;
+		cm->cmsg_type = UDP_SEGMENT;
+		cm->cmsg_len = CMSG_LEN(sizeof(uint16_t));
+		*((uint16_t *) CMSG_DATA(cm)) = gso_len;
+	}
+
+	/* If MSG_MORE, send 1 byte followed by remainder */
+	if (cfg_do_msgmore && len > 1) {
+		iov.iov_len = 1;
+		if (!__send_one(fd, &msg, MSG_MORE))
+			error(1, 0, "send 1B failed");
+
+		iov.iov_base++;
+		iov.iov_len = len - 1;
+	}
+
+	return __send_one(fd, &msg, 0);
+}
+
+static int recv_one(int fd, int flags)
+{
+	int ret;
+
+	ret = recv(fd, buf, sizeof(buf), flags);
+	if (ret == -1 && errno == EAGAIN && (flags & MSG_DONTWAIT))
+		return 0;
+	if (ret == -1)
+		error(1, errno, "recv");
+
+	return ret;
+}
+
+static void run_one(struct testcase *test, int fdt, int fdr,
+		    struct sockaddr *addr, socklen_t alen)
+{
+	int i, ret, val, mss;
+	bool sent;
+
+	fprintf(stderr, "ipv%d tx:%d gso:%d %s\n",
+			addr->sa_family == AF_INET ? 4 : 6,
+			test->tlen, test->gso_len,
+			test->tfail ? "(fail)" : "");
+
+	val = test->gso_len;
+	if (cfg_do_setsockopt) {
+		if (setsockopt(fdt, SOL_UDP, UDP_SEGMENT, &val, sizeof(val)))
+			error(1, errno, "setsockopt udp segment");
+	}
+
+	sent = send_one(fdt, test->tlen, test->gso_len, addr, alen);
+	if (sent && test->tfail)
+		error(1, 0, "send succeeded while expecting failure");
+	if (!sent && !test->tfail)
+		error(1, 0, "send failed while expecting success");
+	if (!sent)
+		return;
+
+	mss = addr->sa_family == AF_INET ? CONST_MSS_V4 : CONST_MSS_V6;
+
+	/* Recv all full MSS datagrams */
+	for (i = 0; i < test->r_num_mss; i++) {
+		ret = recv_one(fdr, 0);
+		if (ret != mss)
+			error(1, 0, "recv.%d: %d != %d", i, ret, mss);
+	}
+
+	/* Recv the non-full last datagram, if tlen was not a multiple of mss */
+	if (test->r_len_last) {
+		ret = recv_one(fdr, 0);
+		if (ret != test->r_len_last)
+			error(1, 0, "recv.%d: %d != %d (last)",
+			      i, ret, test->r_len_last);
+	}
+
+	/* Verify received all data */
+	ret = recv_one(fdr, MSG_DONTWAIT);
+	if (ret)
+		error(1, 0, "recv: unexpected datagram");
+}
+
+static void run_all(int fdt, int fdr, struct sockaddr *addr, socklen_t alen)
+{
+	struct testcase *tests, *test;
+
+	tests = addr->sa_family == AF_INET ? testcases_v4 : testcases_v6;
+
+	for (test = tests; test->tlen; test++) {
+		/* if a specific test is given, then skip all others */
+		if (cfg_specific_test_id == -1 ||
+		    cfg_specific_test_id == test - tests)
+			run_one(test, fdt, fdr, addr, alen);
+	}
+}
+
+static void run_test(struct sockaddr *addr, socklen_t alen)
+{
+	struct timeval tv = { .tv_usec = 100 * 1000 };
+	int fdr, fdt, val;
+
+	fdr = socket(addr->sa_family, SOCK_DGRAM, 0);
+	if (fdr == -1)
+		error(1, errno, "socket r");
+
+	if (bind(fdr, addr, alen))
+		error(1, errno, "bind");
+
+	/* Have tests fail quickly instead of hang */
+	if (setsockopt(fdr, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)))
+		error(1, errno, "setsockopt rcv timeout");
+
+	fdt = socket(addr->sa_family, SOCK_DGRAM, 0);
+	if (fdt == -1)
+		error(1, errno, "socket t");
+
+	/* Do not fragment these datagrams: only succeed if GSO works */
+	set_pmtu_discover(fdt, addr->sa_family == AF_INET);
+
+	if (cfg_do_connectionless) {
+		set_device_mtu(fdt, CONST_MTU_TEST);
+		run_all(fdt, fdr, addr, alen);
+	}
+
+	if (cfg_do_connected) {
+		set_device_mtu(fdt, CONST_MTU_TEST + 100);
+		set_route_mtu(CONST_MTU_TEST, addr->sa_family == AF_INET);
+
+		if (connect(fdt, addr, alen))
+			error(1, errno, "connect");
+
+		val = get_path_mtu(fdt, addr->sa_family == AF_INET);
+		if (val != CONST_MTU_TEST)
+			error(1, 0, "bad path mtu %u\n", val);
+
+		run_all(fdt, fdr, addr, 0 /* use connected addr */);
+	}
+
+	if (close(fdt))
+		error(1, errno, "close t");
+	if (close(fdr))
+		error(1, errno, "close r");
+}
+
+static void run_test_v4(void)
+{
+	struct sockaddr_in addr = {0};
+
+	addr.sin_family = AF_INET;
+	addr.sin_port = htons(cfg_port);
+	addr.sin_addr = addr4;
+
+	run_test((void *)&addr, sizeof(addr));
+}
+
+static void run_test_v6(void)
+{
+	struct sockaddr_in6 addr = {0};
+
+	addr.sin6_family = AF_INET6;
+	addr.sin6_port = htons(cfg_port);
+	addr.sin6_addr = addr6;
+
+	run_test((void *)&addr, sizeof(addr));
+}
+
+static void parse_opts(int argc, char **argv)
+{
+	int c;
+
+	while ((c = getopt(argc, argv, "46cCmst:")) != -1) {
+		switch (c) {
+		case '4':
+			cfg_do_ipv4 = true;
+			break;
+		case '6':
+			cfg_do_ipv6 = true;
+			break;
+		case 'c':
+			cfg_do_connected = true;
+			break;
+		case 'C':
+			cfg_do_connectionless = true;
+			break;
+		case 'm':
+			cfg_do_msgmore = true;
+			break;
+		case 's':
+			cfg_do_setsockopt = true;
+			break;
+		case 't':
+			cfg_specific_test_id = strtoul(optarg, NULL, 0);
+			break;
+		default:
+			error(1, 0, "%s: parse error", argv[0]);
+		}
+	}
+}
+
+int main(int argc, char **argv)
+{
+	parse_opts(argc, argv);
+
+	if (cfg_do_ipv4)
+		run_test_v4();
+	if (cfg_do_ipv6)
+		run_test_v6();
+
+	fprintf(stderr, "OK\n");
+	return 0;
+}
diff --git a/tools/testing/selftests/net/udpgso.sh b/tools/testing/selftests/net/udpgso.sh
new file mode 100755
index 0000000000000000000000000000000000000000..fec24f584fe93aa5ef4ab045091a72be347d95b3
--- /dev/null
+++ b/tools/testing/selftests/net/udpgso.sh
@@ -0,0 +1,29 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Run a series of udpgso regression tests
+
+echo "ipv4 cmsg"
+./in_netns.sh ./udpgso -4 -C
+
+echo "ipv4 setsockopt"
+./in_netns.sh ./udpgso -4 -C -s
+
+echo "ipv6 cmsg"
+./in_netns.sh ./udpgso -6 -C
+
+echo "ipv6 setsockopt"
+./in_netns.sh ./udpgso -6 -C -s
+
+echo "ipv4 connected"
+./in_netns.sh ./udpgso -4 -c
+
+# blocked on 2nd loopback address
+# echo "ipv6 connected"
+# ./in_netns.sh ./udpgso -6 -c
+
+echo "ipv4 msg_more"
+./in_netns.sh ./udpgso -4 -C -m
+
+echo "ipv6 msg_more"
+./in_netns.sh ./udpgso -6 -C -m
diff --git a/tools/testing/selftests/net/udpgso_bench.sh b/tools/testing/selftests/net/udpgso_bench.sh
new file mode 100755
index 0000000000000000000000000000000000000000..792fa4d0285e80e6cd36fdd83e3b5946b0538b3f
--- /dev/null
+++ b/tools/testing/selftests/net/udpgso_bench.sh
@@ -0,0 +1,74 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Run a series of udpgso benchmarks
+
+wake_children() {
+	local -r jobs="$(jobs -p)"
+
+	if [[ "${jobs}" != "" ]]; then
+		kill -1 ${jobs} 2>/dev/null
+	fi
+}
+trap wake_children EXIT
+
+run_one() {
+	local -r args=$@
+
+	./udpgso_bench_rx &
+	./udpgso_bench_rx -t &
+
+	./udpgso_bench_tx ${args}
+}
+
+run_in_netns() {
+	local -r args=$@
+
+	./in_netns.sh $0 __subprocess ${args}
+}
+
+run_udp() {
+	local -r args=$@
+
+	echo "udp"
+	run_in_netns ${args}
+
+	echo "udp gso"
+	run_in_netns ${args} -S
+
+	echo "udp gso zerocopy"
+	run_in_netns ${args} -S -z
+}
+
+run_tcp() {
+	local -r args=$@
+
+	echo "tcp"
+	run_in_netns ${args} -t
+
+	echo "tcp zerocopy"
+	run_in_netns ${args} -t -z
+}
+
+run_all() {
+	local -r core_args="-l 4"
+	local -r ipv4_args="${core_args} -4 -D 127.0.0.1"
+	local -r ipv6_args="${core_args} -6 -D ::1"
+
+	echo "ipv4"
+	run_tcp "${ipv4_args}"
+	run_udp "${ipv4_args}"
+
+	echo "ipv6"
+	run_tcp "${ipv4_args}"
+	run_udp "${ipv6_args}"
+}
+
+if [[ $# -eq 0 ]]; then
+	run_all
+elif [[ $1 == "__subprocess" ]]; then
+	shift
+	run_one $@
+else
+	run_in_netns $@
+fi
diff --git a/tools/testing/selftests/net/udpgso_bench_rx.c b/tools/testing/selftests/net/udpgso_bench_rx.c
new file mode 100644
index 0000000000000000000000000000000000000000..727cf67a3f7586921df5ad8666ad86d9b40cc80f
--- /dev/null
+++ b/tools/testing/selftests/net/udpgso_bench_rx.c
@@ -0,0 +1,265 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+
+#include <arpa/inet.h>
+#include <error.h>
+#include <errno.h>
+#include <limits.h>
+#include <linux/errqueue.h>
+#include <linux/if_packet.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <net/ethernet.h>
+#include <net/if.h>
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <netinet/tcp.h>
+#include <netinet/udp.h>
+#include <poll.h>
+#include <sched.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+static int  cfg_port		= 8000;
+static bool cfg_tcp;
+static bool cfg_verify;
+
+static bool interrupted;
+static unsigned long packets, bytes;
+
+static void sigint_handler(int signum)
+{
+	if (signum == SIGINT)
+		interrupted = true;
+}
+
+static unsigned long gettimeofday_ms(void)
+{
+	struct timeval tv;
+
+	gettimeofday(&tv, NULL);
+	return (tv.tv_sec * 1000) + (tv.tv_usec / 1000);
+}
+
+static void do_poll(int fd)
+{
+	struct pollfd pfd;
+	int ret;
+
+	pfd.events = POLLIN;
+	pfd.revents = 0;
+	pfd.fd = fd;
+
+	do {
+		ret = poll(&pfd, 1, 10);
+		if (ret == -1)
+			error(1, errno, "poll");
+		if (ret == 0)
+			continue;
+		if (pfd.revents != POLLIN)
+			error(1, errno, "poll: 0x%x expected 0x%x\n",
+					pfd.revents, POLLIN);
+	} while (!ret && !interrupted);
+}
+
+static int do_socket(bool do_tcp)
+{
+	struct sockaddr_in6 addr = {0};
+	int fd, val;
+
+	fd = socket(PF_INET6, cfg_tcp ? SOCK_STREAM : SOCK_DGRAM, 0);
+	if (fd == -1)
+		error(1, errno, "socket");
+
+	val = 1 << 21;
+	if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &val, sizeof(val)))
+		error(1, errno, "setsockopt rcvbuf");
+	val = 1;
+	if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, &val, sizeof(val)))
+		error(1, errno, "setsockopt reuseport");
+
+	addr.sin6_family =	PF_INET6;
+	addr.sin6_port =	htons(cfg_port);
+	addr.sin6_addr =	in6addr_any;
+	if (bind(fd, (void *) &addr, sizeof(addr)))
+		error(1, errno, "bind");
+
+	if (do_tcp) {
+		int accept_fd = fd;
+
+		if (listen(accept_fd, 1))
+			error(1, errno, "listen");
+
+		do_poll(accept_fd);
+
+		fd = accept(accept_fd, NULL, NULL);
+		if (fd == -1)
+			error(1, errno, "accept");
+		if (close(accept_fd))
+			error(1, errno, "close accept fd");
+	}
+
+	return fd;
+}
+
+/* Flush all outstanding bytes for the tcp receive queue */
+static void do_flush_tcp(int fd)
+{
+	int ret;
+
+	while (true) {
+		/* MSG_TRUNC flushes up to len bytes */
+		ret = recv(fd, NULL, 1 << 21, MSG_TRUNC | MSG_DONTWAIT);
+		if (ret == -1 && errno == EAGAIN)
+			return;
+		if (ret == -1)
+			error(1, errno, "flush");
+		if (ret == 0) {
+			/* client detached */
+			exit(0);
+		}
+
+		packets++;
+		bytes += ret;
+	}
+
+}
+
+static char sanitized_char(char val)
+{
+	return (val >= 'a' && val <= 'z') ? val : '.';
+}
+
+static void do_verify_udp(const char *data, int len)
+{
+	char cur = data[0];
+	int i;
+
+	/* verify contents */
+	if (cur < 'a' || cur > 'z')
+		error(1, 0, "data initial byte out of range");
+
+	for (i = 1; i < len; i++) {
+		if (cur == 'z')
+			cur = 'a';
+		else
+			cur++;
+
+		if (data[i] != cur)
+			error(1, 0, "data[%d]: len %d, %c(%hhu) != %c(%hhu)\n",
+			      i, len,
+			      sanitized_char(data[i]), data[i],
+			      sanitized_char(cur), cur);
+	}
+}
+
+/* Flush all outstanding datagrams. Verify first few bytes of each. */
+static void do_flush_udp(int fd)
+{
+	static char rbuf[ETH_DATA_LEN];
+	int ret, len, budget = 256;
+
+	len = cfg_verify ? sizeof(rbuf) : 0;
+	while (budget--) {
+		/* MSG_TRUNC will make return value full datagram length */
+		ret = recv(fd, rbuf, len, MSG_TRUNC | MSG_DONTWAIT);
+		if (ret == -1 && errno == EAGAIN)
+			return;
+		if (ret == -1)
+			error(1, errno, "recv");
+		if (len) {
+			if (ret == 0)
+				error(1, errno, "recv: 0 byte datagram\n");
+
+			do_verify_udp(rbuf, ret);
+		}
+
+		packets++;
+		bytes += ret;
+	}
+}
+
+static void usage(const char *filepath)
+{
+	error(1, 0, "Usage: %s [-tv] [-p port]", filepath);
+}
+
+static void parse_opts(int argc, char **argv)
+{
+	int c;
+
+	while ((c = getopt(argc, argv, "ptv")) != -1) {
+		switch (c) {
+		case 'p':
+			cfg_port = htons(strtoul(optarg, NULL, 0));
+			break;
+		case 't':
+			cfg_tcp = true;
+			break;
+		case 'v':
+			cfg_verify = true;
+			break;
+		}
+	}
+
+	if (optind != argc)
+		usage(argv[0]);
+
+	if (cfg_tcp && cfg_verify)
+		error(1, 0, "TODO: implement verify mode for tcp");
+}
+
+static void do_recv(void)
+{
+	unsigned long tnow, treport;
+	int fd;
+
+	fd = do_socket(cfg_tcp);
+
+	treport = gettimeofday_ms() + 1000;
+	do {
+		do_poll(fd);
+
+		if (cfg_tcp)
+			do_flush_tcp(fd);
+		else
+			do_flush_udp(fd);
+
+		tnow = gettimeofday_ms();
+		if (tnow > treport) {
+			if (packets)
+				fprintf(stderr,
+					"%s rx: %6lu MB/s %8lu calls/s\n",
+					cfg_tcp ? "tcp" : "udp",
+					bytes >> 20, packets);
+			bytes = packets = 0;
+			treport = tnow + 1000;
+		}
+
+	} while (!interrupted);
+
+	if (close(fd))
+		error(1, errno, "close");
+}
+
+int main(int argc, char **argv)
+{
+	parse_opts(argc, argv);
+
+	signal(SIGINT, sigint_handler);
+
+	do_recv();
+
+	return 0;
+}
diff --git a/tools/testing/selftests/net/udpgso_bench_tx.c b/tools/testing/selftests/net/udpgso_bench_tx.c
new file mode 100644
index 0000000000000000000000000000000000000000..e821564053cfb7d0482bb85800c7d8f0d977232f
--- /dev/null
+++ b/tools/testing/selftests/net/udpgso_bench_tx.c
@@ -0,0 +1,420 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <error.h>
+#include <netinet/if_ether.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <netinet/udp.h>
+#include <poll.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#ifndef ETH_MAX_MTU
+#define ETH_MAX_MTU 0xFFFFU
+#endif
+
+#ifndef UDP_SEGMENT
+#define UDP_SEGMENT		103
+#endif
+
+#ifndef SO_ZEROCOPY
+#define SO_ZEROCOPY	60
+#endif
+
+#ifndef MSG_ZEROCOPY
+#define MSG_ZEROCOPY	0x4000000
+#endif
+
+#define NUM_PKT		100
+
+static bool	cfg_cache_trash;
+static int	cfg_cpu		= -1;
+static int	cfg_connected	= true;
+static int	cfg_family	= PF_UNSPEC;
+static uint16_t	cfg_mss;
+static int	cfg_payload_len	= (1472 * 42);
+static int	cfg_port	= 8000;
+static int	cfg_runtime_ms	= -1;
+static bool	cfg_segment;
+static bool	cfg_sendmmsg;
+static bool	cfg_tcp;
+static bool	cfg_zerocopy;
+
+static socklen_t cfg_alen;
+static struct sockaddr_storage cfg_dst_addr;
+
+static bool interrupted;
+static char buf[NUM_PKT][ETH_MAX_MTU];
+
+static void sigint_handler(int signum)
+{
+	if (signum == SIGINT)
+		interrupted = true;
+}
+
+static unsigned long gettimeofday_ms(void)
+{
+	struct timeval tv;
+
+	gettimeofday(&tv, NULL);
+	return (tv.tv_sec * 1000) + (tv.tv_usec / 1000);
+}
+
+static int set_cpu(int cpu)
+{
+	cpu_set_t mask;
+
+	CPU_ZERO(&mask);
+	CPU_SET(cpu, &mask);
+	if (sched_setaffinity(0, sizeof(mask), &mask))
+		error(1, 0, "setaffinity %d", cpu);
+
+	return 0;
+}
+
+static void setup_sockaddr(int domain, const char *str_addr, void *sockaddr)
+{
+	struct sockaddr_in6 *addr6 = (void *) sockaddr;
+	struct sockaddr_in *addr4 = (void *) sockaddr;
+
+	switch (domain) {
+	case PF_INET:
+		addr4->sin_family = AF_INET;
+		addr4->sin_port = htons(cfg_port);
+		if (inet_pton(AF_INET, str_addr, &(addr4->sin_addr)) != 1)
+			error(1, 0, "ipv4 parse error: %s", str_addr);
+		break;
+	case PF_INET6:
+		addr6->sin6_family = AF_INET6;
+		addr6->sin6_port = htons(cfg_port);
+		if (inet_pton(AF_INET6, str_addr, &(addr6->sin6_addr)) != 1)
+			error(1, 0, "ipv6 parse error: %s", str_addr);
+		break;
+	default:
+		error(1, 0, "illegal domain");
+	}
+}
+
+static void flush_zerocopy(int fd)
+{
+	struct msghdr msg = {0};	/* flush */
+	int ret;
+
+	while (1) {
+		ret = recvmsg(fd, &msg, MSG_ERRQUEUE);
+		if (ret == -1 && errno == EAGAIN)
+			break;
+		if (ret == -1)
+			error(1, errno, "errqueue");
+		if (msg.msg_flags != (MSG_ERRQUEUE | MSG_CTRUNC))
+			error(1, 0, "errqueue: flags 0x%x\n", msg.msg_flags);
+		msg.msg_flags = 0;
+	}
+}
+
+static int send_tcp(int fd, char *data)
+{
+	int ret, done = 0, count = 0;
+
+	while (done < cfg_payload_len) {
+		ret = send(fd, data + done, cfg_payload_len - done,
+			   cfg_zerocopy ? MSG_ZEROCOPY : 0);
+		if (ret == -1)
+			error(1, errno, "write");
+
+		done += ret;
+		count++;
+	}
+
+	return count;
+}
+
+static int send_udp(int fd, char *data)
+{
+	int ret, total_len, len, count = 0;
+
+	total_len = cfg_payload_len;
+
+	while (total_len) {
+		len = total_len < cfg_mss ? total_len : cfg_mss;
+
+		ret = sendto(fd, data, len, cfg_zerocopy ? MSG_ZEROCOPY : 0,
+			     cfg_connected ? NULL : (void *)&cfg_dst_addr,
+			     cfg_connected ? 0 : cfg_alen);
+		if (ret == -1)
+			error(1, errno, "write");
+		if (ret != len)
+			error(1, errno, "write: %uB != %uB\n", ret, len);
+
+		total_len -= len;
+		count++;
+	}
+
+	return count;
+}
+
+static int send_udp_sendmmsg(int fd, char *data)
+{
+	const int max_nr_msg = ETH_MAX_MTU / ETH_DATA_LEN;
+	struct mmsghdr mmsgs[max_nr_msg];
+	struct iovec iov[max_nr_msg];
+	unsigned int off = 0, left;
+	int i = 0, ret;
+
+	memset(mmsgs, 0, sizeof(mmsgs));
+
+	left = cfg_payload_len;
+	while (left) {
+		if (i == max_nr_msg)
+			error(1, 0, "sendmmsg: exceeds max_nr_msg");
+
+		iov[i].iov_base = data + off;
+		iov[i].iov_len = cfg_mss < left ? cfg_mss : left;
+
+		mmsgs[i].msg_hdr.msg_iov = iov + i;
+		mmsgs[i].msg_hdr.msg_iovlen = 1;
+
+		off += iov[i].iov_len;
+		left -= iov[i].iov_len;
+		i++;
+	}
+
+	ret = sendmmsg(fd, mmsgs, i, cfg_zerocopy ? MSG_ZEROCOPY : 0);
+	if (ret == -1)
+		error(1, errno, "sendmmsg");
+
+	return ret;
+}
+
+static void send_udp_segment_cmsg(struct cmsghdr *cm)
+{
+	uint16_t *valp;
+
+	cm->cmsg_level = SOL_UDP;
+	cm->cmsg_type = UDP_SEGMENT;
+	cm->cmsg_len = CMSG_LEN(sizeof(cfg_mss));
+	valp = (void *)CMSG_DATA(cm);
+	*valp = cfg_mss;
+}
+
+static int send_udp_segment(int fd, char *data)
+{
+	char control[CMSG_SPACE(sizeof(cfg_mss))] = {0};
+	struct msghdr msg = {0};
+	struct iovec iov = {0};
+	int ret;
+
+	iov.iov_base = data;
+	iov.iov_len = cfg_payload_len;
+
+	msg.msg_iov = &iov;
+	msg.msg_iovlen = 1;
+
+	msg.msg_control = control;
+	msg.msg_controllen = sizeof(control);
+	send_udp_segment_cmsg(CMSG_FIRSTHDR(&msg));
+
+	msg.msg_name = (void *)&cfg_dst_addr;
+	msg.msg_namelen = cfg_alen;
+
+	ret = sendmsg(fd, &msg, cfg_zerocopy ? MSG_ZEROCOPY : 0);
+	if (ret == -1)
+		error(1, errno, "sendmsg");
+	if (ret != iov.iov_len)
+		error(1, 0, "sendmsg: %u != %lu\n", ret, iov.iov_len);
+
+	return 1;
+}
+
+static void usage(const char *filepath)
+{
+	error(1, 0, "Usage: %s [-46cmStuz] [-C cpu] [-D dst ip] [-l secs] [-p port] [-s sendsize]",
+		    filepath);
+}
+
+static void parse_opts(int argc, char **argv)
+{
+	int max_len, hdrlen;
+	int c;
+
+	while ((c = getopt(argc, argv, "46cC:D:l:mp:s:Stuz")) != -1) {
+		switch (c) {
+		case '4':
+			if (cfg_family != PF_UNSPEC)
+				error(1, 0, "Pass one of -4 or -6");
+			cfg_family = PF_INET;
+			cfg_alen = sizeof(struct sockaddr_in);
+			break;
+		case '6':
+			if (cfg_family != PF_UNSPEC)
+				error(1, 0, "Pass one of -4 or -6");
+			cfg_family = PF_INET6;
+			cfg_alen = sizeof(struct sockaddr_in6);
+			break;
+		case 'c':
+			cfg_cache_trash = true;
+			break;
+		case 'C':
+			cfg_cpu = strtol(optarg, NULL, 0);
+			break;
+		case 'D':
+			setup_sockaddr(cfg_family, optarg, &cfg_dst_addr);
+			break;
+		case 'l':
+			cfg_runtime_ms = strtoul(optarg, NULL, 10) * 1000;
+			break;
+		case 'm':
+			cfg_sendmmsg = true;
+			break;
+		case 'p':
+			cfg_port = strtoul(optarg, NULL, 0);
+			break;
+		case 's':
+			cfg_payload_len = strtoul(optarg, NULL, 0);
+			break;
+		case 'S':
+			cfg_segment = true;
+			break;
+		case 't':
+			cfg_tcp = true;
+			break;
+		case 'u':
+			cfg_connected = false;
+			break;
+		case 'z':
+			cfg_zerocopy = true;
+			break;
+		}
+	}
+
+	if (optind != argc)
+		usage(argv[0]);
+
+	if (cfg_family == PF_UNSPEC)
+		error(1, 0, "must pass one of -4 or -6");
+	if (cfg_tcp && !cfg_connected)
+		error(1, 0, "connectionless tcp makes no sense");
+	if (cfg_segment && cfg_sendmmsg)
+		error(1, 0, "cannot combine segment offload and sendmmsg");
+
+	if (cfg_family == PF_INET)
+		hdrlen = sizeof(struct iphdr) + sizeof(struct udphdr);
+	else
+		hdrlen = sizeof(struct ip6_hdr) + sizeof(struct udphdr);
+
+	cfg_mss = ETH_DATA_LEN - hdrlen;
+	max_len = ETH_MAX_MTU - hdrlen;
+
+	if (cfg_payload_len > max_len)
+		error(1, 0, "payload length %u exceeds max %u",
+		      cfg_payload_len, max_len);
+}
+
+static void set_pmtu_discover(int fd, bool is_ipv4)
+{
+	int level, name, val;
+
+	if (is_ipv4) {
+		level	= SOL_IP;
+		name	= IP_MTU_DISCOVER;
+		val	= IP_PMTUDISC_DO;
+	} else {
+		level	= SOL_IPV6;
+		name	= IPV6_MTU_DISCOVER;
+		val	= IPV6_PMTUDISC_DO;
+	}
+
+	if (setsockopt(fd, level, name, &val, sizeof(val)))
+		error(1, errno, "setsockopt path mtu");
+}
+
+int main(int argc, char **argv)
+{
+	unsigned long num_msgs, num_sends;
+	unsigned long tnow, treport, tstop;
+	int fd, i, val;
+
+	parse_opts(argc, argv);
+
+	if (cfg_cpu > 0)
+		set_cpu(cfg_cpu);
+
+	for (i = 0; i < sizeof(buf[0]); i++)
+		buf[0][i] = 'a' + (i % 26);
+	for (i = 1; i < NUM_PKT; i++)
+		memcpy(buf[i], buf[0], sizeof(buf[0]));
+
+	signal(SIGINT, sigint_handler);
+
+	fd = socket(cfg_family, cfg_tcp ? SOCK_STREAM : SOCK_DGRAM, 0);
+	if (fd == -1)
+		error(1, errno, "socket");
+
+	if (cfg_zerocopy) {
+		val = 1;
+		if (setsockopt(fd, SOL_SOCKET, SO_ZEROCOPY, &val, sizeof(val)))
+			error(1, errno, "setsockopt zerocopy");
+	}
+
+	if (cfg_connected &&
+	    connect(fd, (void *)&cfg_dst_addr, cfg_alen))
+		error(1, errno, "connect");
+
+	if (cfg_segment)
+		set_pmtu_discover(fd, cfg_family == PF_INET);
+
+	num_msgs = num_sends = 0;
+	tnow = gettimeofday_ms();
+	tstop = tnow + cfg_runtime_ms;
+	treport = tnow + 1000;
+
+	i = 0;
+	do {
+		if (cfg_tcp)
+			num_sends += send_tcp(fd, buf[i]);
+		else if (cfg_segment)
+			num_sends += send_udp_segment(fd, buf[i]);
+		else if (cfg_sendmmsg)
+			num_sends += send_udp_sendmmsg(fd, buf[i]);
+		else
+			num_sends += send_udp(fd, buf[i]);
+		num_msgs++;
+
+		if (cfg_zerocopy && ((num_msgs & 0xF) == 0))
+			flush_zerocopy(fd);
+
+		tnow = gettimeofday_ms();
+		if (tnow > treport) {
+			fprintf(stderr,
+				"%s tx: %6lu MB/s %8lu calls/s %6lu msg/s\n",
+				cfg_tcp ? "tcp" : "udp",
+				(num_msgs * cfg_payload_len) >> 20,
+				num_sends, num_msgs);
+			num_msgs = num_sends = 0;
+			treport = tnow + 1000;
+		}
+
+		/* cold cache when writing buffer */
+		if (cfg_cache_trash)
+			i = ++i < NUM_PKT ? i : 0;
+
+	} while (!interrupted && (cfg_runtime_ms == -1 || tnow < tstop));
+
+	if (close(fd))
+		error(1, errno, "close");
+
+	return 0;
+}