Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1839 insertions, 0 deletions

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
new file mode 100644
index 000000000..c2c02dea6
--- /dev/null
+++ b/net/ipv6/udp.c
@@ -0,0 +1,1839 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	UDP over IPv6
+ *	Linux INET6 implementation
+ *
+ *	Authors:
+ *	Pedro Roque		<roque@di.fc.ul.pt>
+ *
+ *	Based on linux/ipv4/udp.c
+ *
+ *	Fixes:
+ *	Hideaki YOSHIFUJI	:	sin6_scope_id support
+ *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
+ *	Alexey Kuznetsov		allow both IPv4 and IPv6 sockets to bind
+ *					a single port at the same time.
+ *      Kazunori MIYAZAWA @USAGI:       change process style to use ip6_append_data
+ *      YOSHIFUJI Hideaki @USAGI:	convert /proc/net/udp6 to seq_file.
+ */
+
+#include <linux/bpf-cgroup.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/in6.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/ipv6.h>
+#include <linux/icmpv6.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/indirect_call_wrapper.h>
+
+#include <net/addrconf.h>
+#include <net/ndisc.h>
+#include <net/protocol.h>
+#include <net/transp_v6.h>
+#include <net/ip6_route.h>
+#include <net/raw.h>
+#include <net/seg6.h>
+#include <net/tcp_states.h>
+#include <net/ip6_checksum.h>
+#include <net/ip6_tunnel.h>
+#include <net/xfrm.h>
+#include <net/inet_hashtables.h>
+#include <net/inet6_hashtables.h>
+#include <net/busy_poll.h>
+#include <net/sock_reuseport.h>
+
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <trace/events/skb.h>
+#include "udp_impl.h"
+
+static void udpv6_destruct_sock(struct sock *sk)
+{
+	udp_destruct_common(sk);
+	inet6_sock_destruct(sk);
+}
+
+int udpv6_init_sock(struct sock *sk)
+{
+	skb_queue_head_init(&udp_sk(sk)->reader_queue);
+	sk->sk_destruct = udpv6_destruct_sock;
+	set_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags);
+	return 0;
+}
+
+static u32 udp6_ehashfn(const struct net *net,
+			const struct in6_addr *laddr,
+			const u16 lport,
+			const struct in6_addr *faddr,
+			const __be16 fport)
+{
+	static u32 udp6_ehash_secret __read_mostly;
+	static u32 udp_ipv6_hash_secret __read_mostly;
+
+	u32 lhash, fhash;
+
+	net_get_random_once(&udp6_ehash_secret,
+			    sizeof(udp6_ehash_secret));
+	net_get_random_once(&udp_ipv6_hash_secret,
+			    sizeof(udp_ipv6_hash_secret));
+
+	lhash = (__force u32)laddr->s6_addr32[3];
+	fhash = __ipv6_addr_jhash(faddr, udp_ipv6_hash_secret);
+
+	return __inet6_ehashfn(lhash, lport, fhash, fport,
+			       udp6_ehash_secret + net_hash_mix(net));
+}
+
+int udp_v6_get_port(struct sock *sk, unsigned short snum)
+{
+	unsigned int hash2_nulladdr =
+		ipv6_portaddr_hash(sock_net(sk), &in6addr_any, snum);
+	unsigned int hash2_partial =
+		ipv6_portaddr_hash(sock_net(sk), &sk->sk_v6_rcv_saddr, 0);
+
+	/* precompute partial secondary hash */
+	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
+	return udp_lib_get_port(sk, snum, hash2_nulladdr);
+}
+
+void udp_v6_rehash(struct sock *sk)
+{
+	u16 new_hash = ipv6_portaddr_hash(sock_net(sk),
+					  &sk->sk_v6_rcv_saddr,
+					  inet_sk(sk)->inet_num);
+
+	udp_lib_rehash(sk, new_hash);
+}
+
+static int compute_score(struct sock *sk, struct net *net,
+			 const struct in6_addr *saddr, __be16 sport,
+			 const struct in6_addr *daddr, unsigned short hnum,
+			 int dif, int sdif)
+{
+	int bound_dev_if, score;
+	struct inet_sock *inet;
+	bool dev_match;
+
+	if (!net_eq(sock_net(sk), net) ||
+	    udp_sk(sk)->udp_port_hash != hnum ||
+	    sk->sk_family != PF_INET6)
+		return -1;
+
+	if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
+		return -1;
+
+	score = 0;
+	inet = inet_sk(sk);
+
+	if (inet->inet_dport) {
+		if (inet->inet_dport != sport)
+			return -1;
+		score++;
+	}
+
+	if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
+		if (!ipv6_addr_equal(&sk->sk_v6_daddr, saddr))
+			return -1;
+		score++;
+	}
+
+	bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
+	dev_match = udp_sk_bound_dev_eq(net, bound_dev_if, dif, sdif);
+	if (!dev_match)
+		return -1;
+	if (bound_dev_if)
+		score++;
+
+	if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
+		score++;
+
+	return score;
+}
+
+static struct sock *lookup_reuseport(struct net *net, struct sock *sk,
+				     struct sk_buff *skb,
+				     const struct in6_addr *saddr,
+				     __be16 sport,
+				     const struct in6_addr *daddr,
+				     unsigned int hnum)
+{
+	struct sock *reuse_sk = NULL;
+	u32 hash;
+
+	if (sk->sk_reuseport && sk->sk_state != TCP_ESTABLISHED) {
+		hash = udp6_ehashfn(net, daddr, hnum, saddr, sport);
+		reuse_sk = reuseport_select_sock(sk, hash, skb,
+						 sizeof(struct udphdr));
+	}
+	return reuse_sk;
+}
+
+/* called with rcu_read_lock() */
+static struct sock *udp6_lib_lookup2(struct net *net,
+		const struct in6_addr *saddr, __be16 sport,
+		const struct in6_addr *daddr, unsigned int hnum,
+		int dif, int sdif, struct udp_hslot *hslot2,
+		struct sk_buff *skb)
+{
+	struct sock *sk, *result;
+	int score, badness;
+
+	result = NULL;
+	badness = -1;
+	udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
+		score = compute_score(sk, net, saddr, sport,
+				      daddr, hnum, dif, sdif);
+		if (score > badness) {
+			badness = score;
+			result = lookup_reuseport(net, sk, skb, saddr, sport, daddr, hnum);
+			if (!result) {
+				result = sk;
+				continue;
+			}
+
+			/* Fall back to scoring if group has connections */
+			if (!reuseport_has_conns(sk))
+				return result;
+
+			/* Reuseport logic returned an error, keep original score. */
+			if (IS_ERR(result))
+				continue;
+
+			badness = compute_score(sk, net, saddr, sport,
+						daddr, hnum, dif, sdif);
+		}
+	}
+	return result;
+}
+
+static inline struct sock *udp6_lookup_run_bpf(struct net *net,
+					       struct udp_table *udptable,
+					       struct sk_buff *skb,
+					       const struct in6_addr *saddr,
+					       __be16 sport,
+					       const struct in6_addr *daddr,
+					       u16 hnum, const int dif)
+{
+	struct sock *sk, *reuse_sk;
+	bool no_reuseport;
+
+	if (udptable != &udp_table)
+		return NULL; /* only UDP is supported */
+
+	no_reuseport = bpf_sk_lookup_run_v6(net, IPPROTO_UDP, saddr, sport,
+					    daddr, hnum, dif, &sk);
+	if (no_reuseport || IS_ERR_OR_NULL(sk))
+		return sk;
+
+	reuse_sk = lookup_reuseport(net, sk, skb, saddr, sport, daddr, hnum);
+	if (reuse_sk)
+		sk = reuse_sk;
+	return sk;
+}
+
+/* rcu_read_lock() must be held */
+struct sock *__udp6_lib_lookup(struct net *net,
+			       const struct in6_addr *saddr, __be16 sport,
+			       const struct in6_addr *daddr, __be16 dport,
+			       int dif, int sdif, struct udp_table *udptable,
+			       struct sk_buff *skb)
+{
+	unsigned short hnum = ntohs(dport);
+	unsigned int hash2, slot2;
+	struct udp_hslot *hslot2;
+	struct sock *result, *sk;
+
+	hash2 = ipv6_portaddr_hash(net, daddr, hnum);
+	slot2 = hash2 & udptable->mask;
+	hslot2 = &udptable->hash2[slot2];
+
+	/* Lookup connected or non-wildcard sockets */
+	result = udp6_lib_lookup2(net, saddr, sport,
+				  daddr, hnum, dif, sdif,
+				  hslot2, skb);
+	if (!IS_ERR_OR_NULL(result) && result->sk_state == TCP_ESTABLISHED)
+		goto done;
+
+	/* Lookup redirect from BPF */
+	if (static_branch_unlikely(&bpf_sk_lookup_enabled)) {
+		sk = udp6_lookup_run_bpf(net, udptable, skb,
+					 saddr, sport, daddr, hnum, dif);
+		if (sk) {
+			result = sk;
+			goto done;
+		}
+	}
+
+	/* Got non-wildcard socket or error on first lookup */
+	if (result)
+		goto done;
+
+	/* Lookup wildcard sockets */
+	hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum);
+	slot2 = hash2 & udptable->mask;
+	hslot2 = &udptable->hash2[slot2];
+
+	result = udp6_lib_lookup2(net, saddr, sport,
+				  &in6addr_any, hnum, dif, sdif,
+				  hslot2, skb);
+done:
+	if (IS_ERR(result))
+		return NULL;
+	return result;
+}
+EXPORT_SYMBOL_GPL(__udp6_lib_lookup);
+
+static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb,
+					  __be16 sport, __be16 dport,
+					  struct udp_table *udptable)
+{
+	const struct ipv6hdr *iph = ipv6_hdr(skb);
+
+	return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport,
+				 &iph->daddr, dport, inet6_iif(skb),
+				 inet6_sdif(skb), udptable, skb);
+}
+
+struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
+				 __be16 sport, __be16 dport)
+{
+	const struct ipv6hdr *iph = ipv6_hdr(skb);
+
+	return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport,
+				 &iph->daddr, dport, inet6_iif(skb),
+				 inet6_sdif(skb), &udp_table, NULL);
+}
+
+/* Must be called under rcu_read_lock().
+ * Does increment socket refcount.
+ */
+#if IS_ENABLED(CONFIG_NF_TPROXY_IPV6) || IS_ENABLED(CONFIG_NF_SOCKET_IPV6)
+struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport,
+			     const struct in6_addr *daddr, __be16 dport, int dif)
+{
+	struct sock *sk;
+
+	sk =  __udp6_lib_lookup(net, saddr, sport, daddr, dport,
+				dif, 0, &udp_table, NULL);
+	if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
+		sk = NULL;
+	return sk;
+}
+EXPORT_SYMBOL_GPL(udp6_lib_lookup);
+#endif
+
+/* do not use the scratch area len for jumbogram: their length execeeds the
+ * scratch area space; note that the IP6CB flags is still in the first
+ * cacheline, so checking for jumbograms is cheap
+ */
+static int udp6_skb_len(struct sk_buff *skb)
+{
+	return unlikely(inet6_is_jumbogram(skb)) ? skb->len : udp_skb_len(skb);
+}
+
+/*
+ *	This should be easy, if there is something there we
+ *	return it, otherwise we block.
+ */
+
+int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
+		  int flags, int *addr_len)
+{
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	struct inet_sock *inet = inet_sk(sk);
+	struct sk_buff *skb;
+	unsigned int ulen, copied;
+	int off, err, peeking = flags & MSG_PEEK;
+	int is_udplite = IS_UDPLITE(sk);
+	struct udp_mib __percpu *mib;
+	bool checksum_valid = false;
+	int is_udp4;
+
+	if (flags & MSG_ERRQUEUE)
+		return ipv6_recv_error(sk, msg, len, addr_len);
+
+	if (np->rxpmtu && np->rxopt.bits.rxpmtu)
+		return ipv6_recv_rxpmtu(sk, msg, len, addr_len);
+
+try_again:
+	off = sk_peek_offset(sk, flags);
+	skb = __skb_recv_udp(sk, flags, &off, &err);
+	if (!skb)
+		return err;
+
+	ulen = udp6_skb_len(skb);
+	copied = len;
+	if (copied > ulen - off)
+		copied = ulen - off;
+	else if (copied < ulen)
+		msg->msg_flags |= MSG_TRUNC;
+
+	is_udp4 = (skb->protocol == htons(ETH_P_IP));
+	mib = __UDPX_MIB(sk, is_udp4);
+
+	/*
+	 * If checksum is needed at all, try to do it while copying the
+	 * data.  If the data is truncated, or if we only want a partial
+	 * coverage checksum (UDP-Lite), do it before the copy.
+	 */
+
+	if (copied < ulen || peeking ||
+	    (is_udplite && UDP_SKB_CB(skb)->partial_cov)) {
+		checksum_valid = udp_skb_csum_unnecessary(skb) ||
+				!__udp_lib_checksum_complete(skb);
+		if (!checksum_valid)
+			goto csum_copy_err;
+	}
+
+	if (checksum_valid || udp_skb_csum_unnecessary(skb)) {
+		if (udp_skb_is_linear(skb))
+			err = copy_linear_skb(skb, copied, off, &msg->msg_iter);
+		else
+			err = skb_copy_datagram_msg(skb, off, msg, copied);
+	} else {
+		err = skb_copy_and_csum_datagram_msg(skb, off, msg);
+		if (err == -EINVAL)
+			goto csum_copy_err;
+	}
+	if (unlikely(err)) {
+		if (!peeking) {
+			atomic_inc(&sk->sk_drops);
+			SNMP_INC_STATS(mib, UDP_MIB_INERRORS);
+		}
+		kfree_skb(skb);
+		return err;
+	}
+	if (!peeking)
+		SNMP_INC_STATS(mib, UDP_MIB_INDATAGRAMS);
+
+	sock_recv_cmsgs(msg, sk, skb);
+
+	/* Copy the address. */
+	if (msg->msg_name) {
+		DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
+		sin6->sin6_family = AF_INET6;
+		sin6->sin6_port = udp_hdr(skb)->source;
+		sin6->sin6_flowinfo = 0;
+
+		if (is_udp4) {
+			ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
+					       &sin6->sin6_addr);
+			sin6->sin6_scope_id = 0;
+		} else {
+			sin6->sin6_addr = ipv6_hdr(skb)->saddr;
+			sin6->sin6_scope_id =
+				ipv6_iface_scope_id(&sin6->sin6_addr,
+						    inet6_iif(skb));
+		}
+		*addr_len = sizeof(*sin6);
+
+		BPF_CGROUP_RUN_PROG_UDP6_RECVMSG_LOCK(sk,
+						      (struct sockaddr *)sin6);
+	}
+
+	if (udp_test_bit(GRO_ENABLED, sk))
+		udp_cmsg_recv(msg, sk, skb);
+
+	if (np->rxopt.all)
+		ip6_datagram_recv_common_ctl(sk, msg, skb);
+
+	if (is_udp4) {
+		if (inet->cmsg_flags)
+			ip_cmsg_recv_offset(msg, sk, skb,
+					    sizeof(struct udphdr), off);
+	} else {
+		if (np->rxopt.all)
+			ip6_datagram_recv_specific_ctl(sk, msg, skb);
+	}
+
+	err = copied;
+	if (flags & MSG_TRUNC)
+		err = ulen;
+
+	skb_consume_udp(sk, skb, peeking ? -err : err);
+	return err;
+
+csum_copy_err:
+	if (!__sk_queue_drop_skb(sk, &udp_sk(sk)->reader_queue, skb, flags,
+				 udp_skb_destructor)) {
+		SNMP_INC_STATS(mib, UDP_MIB_CSUMERRORS);
+		SNMP_INC_STATS(mib, UDP_MIB_INERRORS);
+	}
+	kfree_skb(skb);
+
+	/* starting over for a new packet, but check if we need to yield */
+	cond_resched();
+	msg->msg_flags &= ~MSG_TRUNC;
+	goto try_again;
+}
+
+DEFINE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
+void udpv6_encap_enable(void)
+{
+	static_branch_inc(&udpv6_encap_needed_key);
+}
+EXPORT_SYMBOL(udpv6_encap_enable);
+
+/* Handler for tunnels with arbitrary destination ports: no socket lookup, go
+ * through error handlers in encapsulations looking for a match.
+ */
+static int __udp6_lib_err_encap_no_sk(struct sk_buff *skb,
+				      struct inet6_skb_parm *opt,
+				      u8 type, u8 code, int offset, __be32 info)
+{
+	int i;
+
+	for (i = 0; i < MAX_IPTUN_ENCAP_OPS; i++) {
+		int (*handler)(struct sk_buff *skb, struct inet6_skb_parm *opt,
+			       u8 type, u8 code, int offset, __be32 info);
+		const struct ip6_tnl_encap_ops *encap;
+
+		encap = rcu_dereference(ip6tun_encaps[i]);
+		if (!encap)
+			continue;
+		handler = encap->err_handler;
+		if (handler && !handler(skb, opt, type, code, offset, info))
+			return 0;
+	}
+
+	return -ENOENT;
+}
+
+/* Try to match ICMP errors to UDP tunnels by looking up a socket without
+ * reversing source and destination port: this will match tunnels that force the
+ * same destination port on both endpoints (e.g. VXLAN, GENEVE). Note that
+ * lwtunnels might actually break this assumption by being configured with
+ * different destination ports on endpoints, in this case we won't be able to
+ * trace ICMP messages back to them.
+ *
+ * If this doesn't match any socket, probe tunnels with arbitrary destination
+ * ports (e.g. FoU, GUE): there, the receiving socket is useless, as the port
+ * we've sent packets to won't necessarily match the local destination port.
+ *
+ * Then ask the tunnel implementation to match the error against a valid
+ * association.
+ *
+ * Return an error if we can't find a match, the socket if we need further
+ * processing, zero otherwise.
+ */
+static struct sock *__udp6_lib_err_encap(struct net *net,
+					 const struct ipv6hdr *hdr, int offset,
+					 struct udphdr *uh,
+					 struct udp_table *udptable,
+					 struct sock *sk,
+					 struct sk_buff *skb,
+					 struct inet6_skb_parm *opt,
+					 u8 type, u8 code, __be32 info)
+{
+	int (*lookup)(struct sock *sk, struct sk_buff *skb);
+	int network_offset, transport_offset;
+	struct udp_sock *up;
+
+	network_offset = skb_network_offset(skb);
+	transport_offset = skb_transport_offset(skb);
+
+	/* Network header needs to point to the outer IPv6 header inside ICMP */
+	skb_reset_network_header(skb);
+
+	/* Transport header needs to point to the UDP header */
+	skb_set_transport_header(skb, offset);
+
+	if (sk) {
+		up = udp_sk(sk);
+
+		lookup = READ_ONCE(up->encap_err_lookup);
+		if (lookup && lookup(sk, skb))
+			sk = NULL;
+
+		goto out;
+	}
+
+	sk = __udp6_lib_lookup(net, &hdr->daddr, uh->source,
+			       &hdr->saddr, uh->dest,
+			       inet6_iif(skb), 0, udptable, skb);
+	if (sk) {
+		up = udp_sk(sk);
+
+		lookup = READ_ONCE(up->encap_err_lookup);
+		if (!lookup || lookup(sk, skb))
+			sk = NULL;
+	}
+
+out:
+	if (!sk) {
+		sk = ERR_PTR(__udp6_lib_err_encap_no_sk(skb, opt, type, code,
+							offset, info));
+	}
+
+	skb_set_transport_header(skb, transport_offset);
+	skb_set_network_header(skb, network_offset);
+
+	return sk;
+}
+
+int __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
+		   u8 type, u8 code, int offset, __be32 info,
+		   struct udp_table *udptable)
+{
+	struct ipv6_pinfo *np;
+	const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
+	const struct in6_addr *saddr = &hdr->saddr;
+	const struct in6_addr *daddr = seg6_get_daddr(skb, opt) ? : &hdr->daddr;
+	struct udphdr *uh = (struct udphdr *)(skb->data+offset);
+	bool tunnel = false;
+	struct sock *sk;
+	int harderr;
+	int err;
+	struct net *net = dev_net(skb->dev);
+
+	sk = __udp6_lib_lookup(net, daddr, uh->dest, saddr, uh->source,
+			       inet6_iif(skb), inet6_sdif(skb), udptable, NULL);
+
+	if (!sk || READ_ONCE(udp_sk(sk)->encap_type)) {
+		/* No socket for error: try tunnels before discarding */
+		if (static_branch_unlikely(&udpv6_encap_needed_key)) {
+			sk = __udp6_lib_err_encap(net, hdr, offset, uh,
+						  udptable, sk, skb,
+						  opt, type, code, info);
+			if (!sk)
+				return 0;
+		} else
+			sk = ERR_PTR(-ENOENT);
+
+		if (IS_ERR(sk)) {
+			__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
+					  ICMP6_MIB_INERRORS);
+			return PTR_ERR(sk);
+		}
+
+		tunnel = true;
+	}
+
+	harderr = icmpv6_err_convert(type, code, &err);
+	np = inet6_sk(sk);
+
+	if (type == ICMPV6_PKT_TOOBIG) {
+		if (!ip6_sk_accept_pmtu(sk))
+			goto out;
+		ip6_sk_update_pmtu(skb, sk, info);
+		if (np->pmtudisc != IPV6_PMTUDISC_DONT)
+			harderr = 1;
+	}
+	if (type == NDISC_REDIRECT) {
+		if (tunnel) {
+			ip6_redirect(skb, sock_net(sk), inet6_iif(skb),
+				     READ_ONCE(sk->sk_mark), sk->sk_uid);
+		} else {
+			ip6_sk_redirect(skb, sk);
+		}
+		goto out;
+	}
+
+	/* Tunnels don't have an application socket: don't pass errors back */
+	if (tunnel) {
+		if (udp_sk(sk)->encap_err_rcv)
+			udp_sk(sk)->encap_err_rcv(sk, skb, offset);
+		goto out;
+	}
+
+	if (!np->recverr) {
+		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
+			goto out;
+	} else {
+		ipv6_icmp_error(sk, skb, err, uh->dest, ntohl(info), (u8 *)(uh+1));
+	}
+
+	sk->sk_err = err;
+	sk_error_report(sk);
+out:
+	return 0;
+}
+
+static int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
+{
+	int rc;
+
+	if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
+		sock_rps_save_rxhash(sk, skb);
+		sk_mark_napi_id(sk, skb);
+		sk_incoming_cpu_update(sk);
+	} else {
+		sk_mark_napi_id_once(sk, skb);
+	}
+
+	rc = __udp_enqueue_schedule_skb(sk, skb);
+	if (rc < 0) {
+		int is_udplite = IS_UDPLITE(sk);
+		enum skb_drop_reason drop_reason;
+
+		/* Note that an ENOMEM error is charged twice */
+		if (rc == -ENOMEM) {
+			UDP6_INC_STATS(sock_net(sk),
+					 UDP_MIB_RCVBUFERRORS, is_udplite);
+			drop_reason = SKB_DROP_REASON_SOCKET_RCVBUFF;
+		} else {
+			UDP6_INC_STATS(sock_net(sk),
+				       UDP_MIB_MEMERRORS, is_udplite);
+			drop_reason = SKB_DROP_REASON_PROTO_MEM;
+		}
+		UDP6_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
+		kfree_skb_reason(skb, drop_reason);
+		return -1;
+	}
+
+	return 0;
+}
+
+static __inline__ int udpv6_err(struct sk_buff *skb,
+				struct inet6_skb_parm *opt, u8 type,
+				u8 code, int offset, __be32 info)
+{
+	return __udp6_lib_err(skb, opt, type, code, offset, info, &udp_table);
+}
+
+static int udpv6_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
+{
+	enum skb_drop_reason drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;
+	struct udp_sock *up = udp_sk(sk);
+	int is_udplite = IS_UDPLITE(sk);
+
+	if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb)) {
+		drop_reason = SKB_DROP_REASON_XFRM_POLICY;
+		goto drop;
+	}
+	nf_reset_ct(skb);
+
+	if (static_branch_unlikely(&udpv6_encap_needed_key) &&
+	    READ_ONCE(up->encap_type)) {
+		int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
+
+		/*
+		 * This is an encapsulation socket so pass the skb to
+		 * the socket's udp_encap_rcv() hook. Otherwise, just
+		 * fall through and pass this up the UDP socket.
+		 * up->encap_rcv() returns the following value:
+		 * =0 if skb was successfully passed to the encap
+		 *    handler or was discarded by it.
+		 * >0 if skb should be passed on to UDP.
+		 * <0 if skb should be resubmitted as proto -N
+		 */
+
+		/* if we're overly short, let UDP handle it */
+		encap_rcv = READ_ONCE(up->encap_rcv);
+		if (encap_rcv) {
+			int ret;
+
+			/* Verify checksum before giving to encap */
+			if (udp_lib_checksum_complete(skb))
+				goto csum_error;
+
+			ret = encap_rcv(sk, skb);
+			if (ret <= 0) {
+				__UDP6_INC_STATS(sock_net(sk),
+						 UDP_MIB_INDATAGRAMS,
+						 is_udplite);
+				return -ret;
+			}
+		}
+
+		/* FALLTHROUGH -- it's a UDP Packet */
+	}
+
+	/*
+	 * UDP-Lite specific tests, ignored on UDP sockets (see net/ipv4/udp.c).
+	 */
+	if ((up->pcflag & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {
+
+		if (up->pcrlen == 0) {          /* full coverage was set  */
+			net_dbg_ratelimited("UDPLITE6: partial coverage %d while full coverage %d requested\n",
+					    UDP_SKB_CB(skb)->cscov, skb->len);
+			goto drop;
+		}
+		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
+			net_dbg_ratelimited("UDPLITE6: coverage %d too small, need min %d\n",
+					    UDP_SKB_CB(skb)->cscov, up->pcrlen);
+			goto drop;
+		}
+	}
+
+	prefetch(&sk->sk_rmem_alloc);
+	if (rcu_access_pointer(sk->sk_filter) &&
+	    udp_lib_checksum_complete(skb))
+		goto csum_error;
+
+	if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr))) {
+		drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
+		goto drop;
+	}
+
+	udp_csum_pull_header(skb);
+
+	skb_dst_drop(skb);
+
+	return __udpv6_queue_rcv_skb(sk, skb);
+
+csum_error:
+	drop_reason = SKB_DROP_REASON_UDP_CSUM;
+	__UDP6_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
+drop:
+	__UDP6_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
+	atomic_inc(&sk->sk_drops);
+	kfree_skb_reason(skb, drop_reason);
+	return -1;
+}
+
+static int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
+{
+	struct sk_buff *next, *segs;
+	int ret;
+
+	if (likely(!udp_unexpected_gso(sk, skb)))
+		return udpv6_queue_rcv_one_skb(sk, skb);
+
+	__skb_push(skb, -skb_mac_offset(skb));
+	segs = udp_rcv_segment(sk, skb, false);
+	skb_list_walk_safe(segs, skb, next) {
+		__skb_pull(skb, skb_transport_offset(skb));
+
+		udp_post_segment_fix_csum(skb);
+		ret = udpv6_queue_rcv_one_skb(sk, skb);
+		if (ret > 0)
+			ip6_protocol_deliver_rcu(dev_net(skb->dev), skb, ret,
+						 true);
+	}
+	return 0;
+}
+
+static bool __udp_v6_is_mcast_sock(struct net *net, struct sock *sk,
+				   __be16 loc_port, const struct in6_addr *loc_addr,
+				   __be16 rmt_port, const struct in6_addr *rmt_addr,
+				   int dif, int sdif, unsigned short hnum)
+{
+	struct inet_sock *inet = inet_sk(sk);
+
+	if (!net_eq(sock_net(sk), net))
+		return false;
+
+	if (udp_sk(sk)->udp_port_hash != hnum ||
+	    sk->sk_family != PF_INET6 ||
+	    (inet->inet_dport && inet->inet_dport != rmt_port) ||
+	    (!ipv6_addr_any(&sk->sk_v6_daddr) &&
+		    !ipv6_addr_equal(&sk->sk_v6_daddr, rmt_addr)) ||
+	    !udp_sk_bound_dev_eq(net, READ_ONCE(sk->sk_bound_dev_if), dif, sdif) ||
+	    (!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
+		    !ipv6_addr_equal(&sk->sk_v6_rcv_saddr, loc_addr)))
+		return false;
+	if (!inet6_mc_check(sk, loc_addr, rmt_addr))
+		return false;
+	return true;
+}
+
+static void udp6_csum_zero_error(struct sk_buff *skb)
+{
+	/* RFC 2460 section 8.1 says that we SHOULD log
+	 * this error. Well, it is reasonable.
+	 */
+	net_dbg_ratelimited("IPv6: udp checksum is 0 for [%pI6c]:%u->[%pI6c]:%u\n",
+			    &ipv6_hdr(skb)->saddr, ntohs(udp_hdr(skb)->source),
+			    &ipv6_hdr(skb)->daddr, ntohs(udp_hdr(skb)->dest));
+}
+
+/*
+ * Note: called only from the BH handler context,
+ * so we don't need to lock the hashes.
+ */
+static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
+		const struct in6_addr *saddr, const struct in6_addr *daddr,
+		struct udp_table *udptable, int proto)
+{
+	struct sock *sk, *first = NULL;
+	const struct udphdr *uh = udp_hdr(skb);
+	unsigned short hnum = ntohs(uh->dest);
+	struct udp_hslot *hslot = udp_hashslot(udptable, net, hnum);
+	unsigned int offset = offsetof(typeof(*sk), sk_node);
+	unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10);
+	int dif = inet6_iif(skb);
+	int sdif = inet6_sdif(skb);
+	struct hlist_node *node;
+	struct sk_buff *nskb;
+
+	if (use_hash2) {
+		hash2_any = ipv6_portaddr_hash(net, &in6addr_any, hnum) &
+			    udptable->mask;
+		hash2 = ipv6_portaddr_hash(net, daddr, hnum) & udptable->mask;
+start_lookup:
+		hslot = &udptable->hash2[hash2];
+		offset = offsetof(typeof(*sk), __sk_common.skc_portaddr_node);
+	}
+
+	sk_for_each_entry_offset_rcu(sk, node, &hslot->head, offset) {
+		if (!__udp_v6_is_mcast_sock(net, sk, uh->dest, daddr,
+					    uh->source, saddr, dif, sdif,
+					    hnum))
+			continue;
+		/* If zero checksum and no_check is not on for
+		 * the socket then skip it.
+		 */
+		if (!uh->check && !udp_get_no_check6_rx(sk))
+			continue;
+		if (!first) {
+			first = sk;
+			continue;
+		}
+		nskb = skb_clone(skb, GFP_ATOMIC);
+		if (unlikely(!nskb)) {
+			atomic_inc(&sk->sk_drops);
+			__UDP6_INC_STATS(net, UDP_MIB_RCVBUFERRORS,
+					 IS_UDPLITE(sk));
+			__UDP6_INC_STATS(net, UDP_MIB_INERRORS,
+					 IS_UDPLITE(sk));
+			continue;
+		}
+
+		if (udpv6_queue_rcv_skb(sk, nskb) > 0)
+			consume_skb(nskb);
+	}
+
+	/* Also lookup *:port if we are using hash2 and haven't done so yet. */
+	if (use_hash2 && hash2 != hash2_any) {
+		hash2 = hash2_any;
+		goto start_lookup;
+	}
+
+	if (first) {
+		if (udpv6_queue_rcv_skb(first, skb) > 0)
+			consume_skb(skb);
+	} else {
+		kfree_skb(skb);
+		__UDP6_INC_STATS(net, UDP_MIB_IGNOREDMULTI,
+				 proto == IPPROTO_UDPLITE);
+	}
+	return 0;
+}
+
+static void udp6_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
+{
+	if (udp_sk_rx_dst_set(sk, dst)) {
+		const struct rt6_info *rt = (const struct rt6_info *)dst;
+
+		sk->sk_rx_dst_cookie = rt6_get_cookie(rt);
+	}
+}
+
+/* wrapper for udp_queue_rcv_skb tacking care of csum conversion and
+ * return code conversion for ip layer consumption
+ */
+static int udp6_unicast_rcv_skb(struct sock *sk, struct sk_buff *skb,
+				struct udphdr *uh)
+{
+	int ret;
+
+	if (inet_get_convert_csum(sk) && uh->check && !IS_UDPLITE(sk))
+		skb_checksum_try_convert(skb, IPPROTO_UDP, ip6_compute_pseudo);
+
+	ret = udpv6_queue_rcv_skb(sk, skb);
+
+	/* a return value > 0 means to resubmit the input */
+	if (ret > 0)
+		return ret;
+	return 0;
+}
+
+int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
+		   int proto)
+{
+	enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
+	const struct in6_addr *saddr, *daddr;
+	struct net *net = dev_net(skb->dev);
+	struct udphdr *uh;
+	struct sock *sk;
+	bool refcounted;
+	u32 ulen = 0;
+
+	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
+		goto discard;
+
+	saddr = &ipv6_hdr(skb)->saddr;
+	daddr = &ipv6_hdr(skb)->daddr;
+	uh = udp_hdr(skb);
+
+	ulen = ntohs(uh->len);
+	if (ulen > skb->len)
+		goto short_packet;
+
+	if (proto == IPPROTO_UDP) {
+		/* UDP validates ulen. */
+
+		/* Check for jumbo payload */
+		if (ulen == 0)
+			ulen = skb->len;
+
+		if (ulen < sizeof(*uh))
+			goto short_packet;
+
+		if (ulen < skb->len) {
+			if (pskb_trim_rcsum(skb, ulen))
+				goto short_packet;
+			saddr = &ipv6_hdr(skb)->saddr;
+			daddr = &ipv6_hdr(skb)->daddr;
+			uh = udp_hdr(skb);
+		}
+	}
+
+	if (udp6_csum_init(skb, uh, proto))
+		goto csum_error;
+
+	/* Check if the socket is already available, e.g. due to early demux */
+	sk = skb_steal_sock(skb, &refcounted);
+	if (sk) {
+		struct dst_entry *dst = skb_dst(skb);
+		int ret;
+
+		if (unlikely(rcu_dereference(sk->sk_rx_dst) != dst))
+			udp6_sk_rx_dst_set(sk, dst);
+
+		if (!uh->check && !udp_get_no_check6_rx(sk)) {
+			if (refcounted)
+				sock_put(sk);
+			goto report_csum_error;
+		}
+
+		ret = udp6_unicast_rcv_skb(sk, skb, uh);
+		if (refcounted)
+			sock_put(sk);
+		return ret;
+	}
+
+	/*
+	 *	Multicast receive code
+	 */
+	if (ipv6_addr_is_multicast(daddr))
+		return __udp6_lib_mcast_deliver(net, skb,
+				saddr, daddr, udptable, proto);
+
+	/* Unicast */
+	sk = __udp6_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
+	if (sk) {
+		if (!uh->check && !udp_get_no_check6_rx(sk))
+			goto report_csum_error;
+		return udp6_unicast_rcv_skb(sk, skb, uh);
+	}
+
+	reason = SKB_DROP_REASON_NO_SOCKET;
+
+	if (!uh->check)
+		goto report_csum_error;
+
+	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
+		goto discard;
+	nf_reset_ct(skb);
+
+	if (udp_lib_checksum_complete(skb))
+		goto csum_error;
+
+	__UDP6_INC_STATS(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
+	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
+
+	kfree_skb_reason(skb, reason);
+	return 0;
+
+short_packet:
+	if (reason == SKB_DROP_REASON_NOT_SPECIFIED)
+		reason = SKB_DROP_REASON_PKT_TOO_SMALL;
+	net_dbg_ratelimited("UDP%sv6: short packet: From [%pI6c]:%u %d/%d to [%pI6c]:%u\n",
+			    proto == IPPROTO_UDPLITE ? "-Lite" : "",
+			    saddr, ntohs(uh->source),
+			    ulen, skb->len,
+			    daddr, ntohs(uh->dest));
+	goto discard;
+
+report_csum_error:
+	udp6_csum_zero_error(skb);
+csum_error:
+	if (reason == SKB_DROP_REASON_NOT_SPECIFIED)
+		reason = SKB_DROP_REASON_UDP_CSUM;
+	__UDP6_INC_STATS(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
+discard:
+	__UDP6_INC_STATS(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
+	kfree_skb_reason(skb, reason);
+	return 0;
+}
+
+
+static struct sock *__udp6_lib_demux_lookup(struct net *net,
+			__be16 loc_port, const struct in6_addr *loc_addr,
+			__be16 rmt_port, const struct in6_addr *rmt_addr,
+			int dif, int sdif)
+{
+	unsigned short hnum = ntohs(loc_port);
+	unsigned int hash2, slot2;
+	struct udp_hslot *hslot2;
+	__portpair ports;
+	struct sock *sk;
+
+	hash2 = ipv6_portaddr_hash(net, loc_addr, hnum);
+	slot2 = hash2 & udp_table.mask;
+	hslot2 = &udp_table.hash2[slot2];
+	ports = INET_COMBINED_PORTS(rmt_port, hnum);
+
+	udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
+		if (sk->sk_state == TCP_ESTABLISHED &&
+		    inet6_match(net, sk, rmt_addr, loc_addr, ports, dif, sdif))
+			return sk;
+		/* Only check first socket in chain */
+		break;
+	}
+	return NULL;
+}
+
+void udp_v6_early_demux(struct sk_buff *skb)
+{
+	struct net *net = dev_net(skb->dev);
+	const struct udphdr *uh;
+	struct sock *sk;
+	struct dst_entry *dst;
+	int dif = skb->dev->ifindex;
+	int sdif = inet6_sdif(skb);
+
+	if (!pskb_may_pull(skb, skb_transport_offset(skb) +
+	    sizeof(struct udphdr)))
+		return;
+
+	uh = udp_hdr(skb);
+
+	if (skb->pkt_type == PACKET_HOST)
+		sk = __udp6_lib_demux_lookup(net, uh->dest,
+					     &ipv6_hdr(skb)->daddr,
+					     uh->source, &ipv6_hdr(skb)->saddr,
+					     dif, sdif);
+	else
+		return;
+
+	if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt))
+		return;
+
+	skb->sk = sk;
+	skb->destructor = sock_efree;
+	dst = rcu_dereference(sk->sk_rx_dst);
+
+	if (dst)
+		dst = dst_check(dst, sk->sk_rx_dst_cookie);
+	if (dst) {
+		/* set noref for now.
+		 * any place which wants to hold dst has to call
+		 * dst_hold_safe()
+		 */
+		skb_dst_set_noref(skb, dst);
+	}
+}
+
+INDIRECT_CALLABLE_SCOPE int udpv6_rcv(struct sk_buff *skb)
+{
+	return __udp6_lib_rcv(skb, &udp_table, IPPROTO_UDP);
+}
+
+/*
+ * Throw away all pending data and cancel the corking. Socket is locked.
+ */
+static void udp_v6_flush_pending_frames(struct sock *sk)
+{
+	struct udp_sock *up = udp_sk(sk);
+
+	if (up->pending == AF_INET)
+		udp_flush_pending_frames(sk);
+	else if (up->pending) {
+		up->len = 0;
+		WRITE_ONCE(up->pending, 0);
+		ip6_flush_pending_frames(sk);
+	}
+}
+
+static int udpv6_pre_connect(struct sock *sk, struct sockaddr *uaddr,
+			     int addr_len)
+{
+	if (addr_len < offsetofend(struct sockaddr, sa_family))
+		return -EINVAL;
+	/* The following checks are replicated from __ip6_datagram_connect()
+	 * and intended to prevent BPF program called below from accessing
+	 * bytes that are out of the bound specified by user in addr_len.
+	 */
+	if (uaddr->sa_family == AF_INET) {
+		if (ipv6_only_sock(sk))
+			return -EAFNOSUPPORT;
+		return udp_pre_connect(sk, uaddr, addr_len);
+	}
+
+	if (addr_len < SIN6_LEN_RFC2133)
+		return -EINVAL;
+
+	return BPF_CGROUP_RUN_PROG_INET6_CONNECT_LOCK(sk, uaddr);
+}
+
+/**
+ *	udp6_hwcsum_outgoing  -  handle outgoing HW checksumming
+ *	@sk:	socket we are sending on
+ *	@skb:	sk_buff containing the filled-in UDP header
+ *		(checksum field must be zeroed out)
+ *	@saddr: source address
+ *	@daddr: destination address
+ *	@len:	length of packet
+ */
+static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
+				 const struct in6_addr *saddr,
+				 const struct in6_addr *daddr, int len)
+{
+	unsigned int offset;
+	struct udphdr *uh = udp_hdr(skb);
+	struct sk_buff *frags = skb_shinfo(skb)->frag_list;
+	__wsum csum = 0;
+
+	if (!frags) {
+		/* Only one fragment on the socket.  */
+		skb->csum_start = skb_transport_header(skb) - skb->head;
+		skb->csum_offset = offsetof(struct udphdr, check);
+		uh->check = ~csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP, 0);
+	} else {
+		/*
+		 * HW-checksum won't work as there are two or more
+		 * fragments on the socket so that all csums of sk_buffs
+		 * should be together
+		 */
+		offset = skb_transport_offset(skb);
+		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
+		csum = skb->csum;
+
+		skb->ip_summed = CHECKSUM_NONE;
+
+		do {
+			csum = csum_add(csum, frags->csum);
+		} while ((frags = frags->next));
+
+		uh->check = csum_ipv6_magic(saddr, daddr, len, IPPROTO_UDP,
+					    csum);
+		if (uh->check == 0)
+			uh->check = CSUM_MANGLED_0;
+	}
+}
+
+/*
+ *	Sending
+ */
+
+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;
+	int err = 0;
+	int is_udplite = IS_UDPLITE(sk);
+	__wsum csum = 0;
+	int offset = skb_transport_offset(skb);
+	int len = skb->len - offset;
+	int datalen = len - sizeof(*uh);
+
+	/*
+	 * Create a UDP header
+	 */
+	uh = udp_hdr(skb);
+	uh->source = fl6->fl6_sport;
+	uh->dest = fl6->fl6_dport;
+	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) {
+			kfree_skb(skb);
+			return -EINVAL;
+		}
+		if (datalen > cork->gso_size * UDP_MAX_SEGMENTS) {
+			kfree_skb(skb);
+			return -EINVAL;
+		}
+		if (udp_get_no_check6_tx(sk)) {
+			kfree_skb(skb);
+			return -EINVAL;
+		}
+		if (skb->ip_summed != CHECKSUM_PARTIAL || is_udplite ||
+		    dst_xfrm(skb_dst(skb))) {
+			kfree_skb(skb);
+			return -EIO;
+		}
+
+		if (datalen > cork->gso_size) {
+			skb_shinfo(skb)->gso_size = cork->gso_size;
+			skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4;
+			skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(datalen,
+								 cork->gso_size);
+		}
+		goto csum_partial;
+	}
+
+	if (is_udplite)
+		csum = udplite_csum(skb);
+	else if (udp_get_no_check6_tx(sk)) {   /* UDP csum disabled */
+		skb->ip_summed = CHECKSUM_NONE;
+		goto send;
+	} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
+csum_partial:
+		udp6_hwcsum_outgoing(sk, skb, &fl6->saddr, &fl6->daddr, len);
+		goto send;
+	} else
+		csum = udp_csum(skb);
+
+	/* add protocol-dependent pseudo-header */
+	uh->check = csum_ipv6_magic(&fl6->saddr, &fl6->daddr,
+				    len, fl6->flowi6_proto, csum);
+	if (uh->check == 0)
+		uh->check = CSUM_MANGLED_0;
+
+send:
+	err = ip6_send_skb(skb);
+	if (err) {
+		if (err == -ENOBUFS && !inet6_sk(sk)->recverr) {
+			UDP6_INC_STATS(sock_net(sk),
+				       UDP_MIB_SNDBUFERRORS, is_udplite);
+			err = 0;
+		}
+	} else {
+		UDP6_INC_STATS(sock_net(sk),
+			       UDP_MIB_OUTDATAGRAMS, is_udplite);
+	}
+	return err;
+}
+
+static int udp_v6_push_pending_frames(struct sock *sk)
+{
+	struct sk_buff *skb;
+	struct udp_sock  *up = udp_sk(sk);
+	int err = 0;
+
+	if (up->pending == AF_INET)
+		return udp_push_pending_frames(sk);
+
+	skb = ip6_finish_skb(sk);
+	if (!skb)
+		goto out;
+
+	err = udp_v6_send_skb(skb, &inet_sk(sk)->cork.fl.u.ip6,
+			      &inet_sk(sk)->cork.base);
+out:
+	up->len = 0;
+	WRITE_ONCE(up->pending, 0);
+	return err;
+}
+
+int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
+{
+	struct ipv6_txoptions opt_space;
+	struct udp_sock *up = udp_sk(sk);
+	struct inet_sock *inet = inet_sk(sk);
+	struct ipv6_pinfo *np = inet6_sk(sk);
+	DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
+	struct in6_addr *daddr, *final_p, final;
+	struct ipv6_txoptions *opt = NULL;
+	struct ipv6_txoptions *opt_to_free = NULL;
+	struct ip6_flowlabel *flowlabel = NULL;
+	struct inet_cork_full cork;
+	struct flowi6 *fl6 = &cork.fl.u.ip6;
+	struct dst_entry *dst;
+	struct ipcm6_cookie ipc6;
+	int addr_len = msg->msg_namelen;
+	bool connected = false;
+	int ulen = len;
+	int corkreq = udp_test_bit(CORK, sk) || msg->msg_flags & MSG_MORE;
+	int err;
+	int is_udplite = IS_UDPLITE(sk);
+	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
+
+	ipcm6_init(&ipc6);
+	ipc6.gso_size = READ_ONCE(up->gso_size);
+	ipc6.sockc.tsflags = READ_ONCE(sk->sk_tsflags);
+	ipc6.sockc.mark = READ_ONCE(sk->sk_mark);
+
+	/* destination address check */
+	if (sin6) {
+		if (addr_len < offsetof(struct sockaddr, sa_data))
+			return -EINVAL;
+
+		switch (sin6->sin6_family) {
+		case AF_INET6:
+			if (addr_len < SIN6_LEN_RFC2133)
+				return -EINVAL;
+			daddr = &sin6->sin6_addr;
+			if (ipv6_addr_any(daddr) &&
+			    ipv6_addr_v4mapped(&np->saddr))
+				ipv6_addr_set_v4mapped(htonl(INADDR_LOOPBACK),
+						       daddr);
+			break;
+		case AF_INET:
+			goto do_udp_sendmsg;
+		case AF_UNSPEC:
+			msg->msg_name = sin6 = NULL;
+			msg->msg_namelen = addr_len = 0;
+			daddr = NULL;
+			break;
+		default:
+			return -EINVAL;
+		}
+	} else if (!READ_ONCE(up->pending)) {
+		if (sk->sk_state != TCP_ESTABLISHED)
+			return -EDESTADDRREQ;
+		daddr = &sk->sk_v6_daddr;
+	} else
+		daddr = NULL;
+
+	if (daddr) {
+		if (ipv6_addr_v4mapped(daddr)) {
+			struct sockaddr_in sin;
+			sin.sin_family = AF_INET;
+			sin.sin_port = sin6 ? sin6->sin6_port : inet->inet_dport;
+			sin.sin_addr.s_addr = daddr->s6_addr32[3];
+			msg->msg_name = &sin;
+			msg->msg_namelen = sizeof(sin);
+do_udp_sendmsg:
+			err = ipv6_only_sock(sk) ?
+				-ENETUNREACH : udp_sendmsg(sk, msg, len);
+			msg->msg_name = sin6;
+			msg->msg_namelen = addr_len;
+			return err;
+		}
+	}
+
+	/* Rough check on arithmetic overflow,
+	   better check is made in ip6_append_data().
+	   */
+	if (len > INT_MAX - sizeof(struct udphdr))
+		return -EMSGSIZE;
+
+	getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;
+	if (READ_ONCE(up->pending)) {
+		if (READ_ONCE(up->pending) == AF_INET)
+			return udp_sendmsg(sk, msg, len);
+		/*
+		 * There are pending frames.
+		 * The socket lock must be held while it's corked.
+		 */
+		lock_sock(sk);
+		if (likely(up->pending)) {
+			if (unlikely(up->pending != AF_INET6)) {
+				release_sock(sk);
+				return -EAFNOSUPPORT;
+			}
+			dst = NULL;
+			goto do_append_data;
+		}
+		release_sock(sk);
+	}
+	ulen += sizeof(struct udphdr);
+
+	memset(fl6, 0, sizeof(*fl6));
+
+	if (sin6) {
+		if (sin6->sin6_port == 0)
+			return -EINVAL;
+
+		fl6->fl6_dport = sin6->sin6_port;
+		daddr = &sin6->sin6_addr;
+
+		if (np->sndflow) {
+			fl6->flowlabel = sin6->sin6_flowinfo&IPV6_FLOWINFO_MASK;
+			if (fl6->flowlabel & IPV6_FLOWLABEL_MASK) {
+				flowlabel = fl6_sock_lookup(sk, fl6->flowlabel);
+				if (IS_ERR(flowlabel))
+					return -EINVAL;
+			}
+		}
+
+		/*
+		 * Otherwise it will be difficult to maintain
+		 * sk->sk_dst_cache.
+		 */
+		if (sk->sk_state == TCP_ESTABLISHED &&
+		    ipv6_addr_equal(daddr, &sk->sk_v6_daddr))
+			daddr = &sk->sk_v6_daddr;
+
+		if (addr_len >= sizeof(struct sockaddr_in6) &&
+		    sin6->sin6_scope_id &&
+		    __ipv6_addr_needs_scope_id(__ipv6_addr_type(daddr)))
+			fl6->flowi6_oif = sin6->sin6_scope_id;
+	} else {
+		if (sk->sk_state != TCP_ESTABLISHED)
+			return -EDESTADDRREQ;
+
+		fl6->fl6_dport = inet->inet_dport;
+		daddr = &sk->sk_v6_daddr;
+		fl6->flowlabel = np->flow_label;
+		connected = true;
+	}
+
+	if (!fl6->flowi6_oif)
+		fl6->flowi6_oif = READ_ONCE(sk->sk_bound_dev_if);
+
+	if (!fl6->flowi6_oif)
+		fl6->flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
+
+	fl6->flowi6_uid = sk->sk_uid;
+
+	if (msg->msg_controllen) {
+		opt = &opt_space;
+		memset(opt, 0, sizeof(struct ipv6_txoptions));
+		opt->tot_len = sizeof(*opt);
+		ipc6.opt = opt;
+
+		err = udp_cmsg_send(sk, msg, &ipc6.gso_size);
+		if (err > 0)
+			err = ip6_datagram_send_ctl(sock_net(sk), sk, msg, fl6,
+						    &ipc6);
+		if (err < 0) {
+			fl6_sock_release(flowlabel);
+			return err;
+		}
+		if ((fl6->flowlabel&IPV6_FLOWLABEL_MASK) && !flowlabel) {
+			flowlabel = fl6_sock_lookup(sk, fl6->flowlabel);
+			if (IS_ERR(flowlabel))
+				return -EINVAL;
+		}
+		if (!(opt->opt_nflen|opt->opt_flen))
+			opt = NULL;
+		connected = false;
+	}
+	if (!opt) {
+		opt = txopt_get(np);
+		opt_to_free = opt;
+	}
+	if (flowlabel)
+		opt = fl6_merge_options(&opt_space, flowlabel, opt);
+	opt = ipv6_fixup_options(&opt_space, opt);
+	ipc6.opt = opt;
+
+	fl6->flowi6_proto = sk->sk_protocol;
+	fl6->flowi6_mark = ipc6.sockc.mark;
+	fl6->daddr = *daddr;
+	if (ipv6_addr_any(&fl6->saddr) && !ipv6_addr_any(&np->saddr))
+		fl6->saddr = np->saddr;
+	fl6->fl6_sport = inet->inet_sport;
+
+	if (cgroup_bpf_enabled(CGROUP_UDP6_SENDMSG) && !connected) {
+		err = BPF_CGROUP_RUN_PROG_UDP6_SENDMSG_LOCK(sk,
+					   (struct sockaddr *)sin6,
+					   &fl6->saddr);
+		if (err)
+			goto out_no_dst;
+		if (sin6) {
+			if (ipv6_addr_v4mapped(&sin6->sin6_addr)) {
+				/* BPF program rewrote IPv6-only by IPv4-mapped
+				 * IPv6. It's currently unsupported.
+				 */
+				err = -ENOTSUPP;
+				goto out_no_dst;
+			}
+			if (sin6->sin6_port == 0) {
+				/* BPF program set invalid port. Reject it. */
+				err = -EINVAL;
+				goto out_no_dst;
+			}
+			fl6->fl6_dport = sin6->sin6_port;
+			fl6->daddr = sin6->sin6_addr;
+		}
+	}
+
+	if (ipv6_addr_any(&fl6->daddr))
+		fl6->daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */
+
+	final_p = fl6_update_dst(fl6, opt, &final);
+	if (final_p)
+		connected = false;
+
+	if (!fl6->flowi6_oif && ipv6_addr_is_multicast(&fl6->daddr)) {
+		fl6->flowi6_oif = np->mcast_oif;
+		connected = false;
+	} else if (!fl6->flowi6_oif)
+		fl6->flowi6_oif = np->ucast_oif;
+
+	security_sk_classify_flow(sk, flowi6_to_flowi_common(fl6));
+
+	if (ipc6.tclass < 0)
+		ipc6.tclass = np->tclass;
+
+	fl6->flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6->flowlabel);
+
+	dst = ip6_sk_dst_lookup_flow(sk, fl6, final_p, connected);
+	if (IS_ERR(dst)) {
+		err = PTR_ERR(dst);
+		dst = NULL;
+		goto out;
+	}
+
+	if (ipc6.hlimit < 0)
+		ipc6.hlimit = ip6_sk_dst_hoplimit(np, fl6, dst);
+
+	if (msg->msg_flags&MSG_CONFIRM)
+		goto do_confirm;
+back_from_confirm:
+
+	/* Lockless fast path for the non-corking case */
+	if (!corkreq) {
+		struct sk_buff *skb;
+
+		skb = ip6_make_skb(sk, getfrag, msg, ulen,
+				   sizeof(struct udphdr), &ipc6,
+				   (struct rt6_info *)dst,
+				   msg->msg_flags, &cork);
+		err = PTR_ERR(skb);
+		if (!IS_ERR_OR_NULL(skb))
+			err = udp_v6_send_skb(skb, fl6, &cork.base);
+		/* ip6_make_skb steals dst reference */
+		goto out_no_dst;
+	}
+
+	lock_sock(sk);
+	if (unlikely(up->pending)) {
+		/* The socket is already corked while preparing it. */
+		/* ... which is an evident application bug. --ANK */
+		release_sock(sk);
+
+		net_dbg_ratelimited("udp cork app bug 2\n");
+		err = -EINVAL;
+		goto out;
+	}
+
+	WRITE_ONCE(up->pending, AF_INET6);
+
+do_append_data:
+	if (ipc6.dontfrag < 0)
+		ipc6.dontfrag = np->dontfrag;
+	up->len += ulen;
+	err = ip6_append_data(sk, getfrag, msg, ulen, sizeof(struct udphdr),
+			      &ipc6, fl6, (struct rt6_info *)dst,
+			      corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
+	if (err)
+		udp_v6_flush_pending_frames(sk);
+	else if (!corkreq)
+		err = udp_v6_push_pending_frames(sk);
+	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
+		WRITE_ONCE(up->pending, 0);
+
+	if (err > 0)
+		err = np->recverr ? net_xmit_errno(err) : 0;
+	release_sock(sk);
+
+out:
+	dst_release(dst);
+out_no_dst:
+	fl6_sock_release(flowlabel);
+	txopt_put(opt_to_free);
+	if (!err)
+		return len;
+	/*
+	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
+	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
+	 * we don't have a good statistic (IpOutDiscards but it can be too many
+	 * things).  We could add another new stat but at least for now that
+	 * seems like overkill.
+	 */
+	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
+		UDP6_INC_STATS(sock_net(sk),
+			       UDP_MIB_SNDBUFERRORS, is_udplite);
+	}
+	return err;
+
+do_confirm:
+	if (msg->msg_flags & MSG_PROBE)
+		dst_confirm_neigh(dst, &fl6->daddr);
+	if (!(msg->msg_flags&MSG_PROBE) || len)
+		goto back_from_confirm;
+	err = 0;
+	goto out;
+}
+
+static void udpv6_splice_eof(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+	struct udp_sock *up = udp_sk(sk);
+
+	if (!READ_ONCE(up->pending) || udp_test_bit(CORK, sk))
+		return;
+
+	lock_sock(sk);
+	if (up->pending && !udp_test_bit(CORK, sk))
+		udp_v6_push_pending_frames(sk);
+	release_sock(sk);
+}
+
+void udpv6_destroy_sock(struct sock *sk)
+{
+	struct udp_sock *up = udp_sk(sk);
+	lock_sock(sk);
+
+	/* protects from races with udp_abort() */
+	sock_set_flag(sk, SOCK_DEAD);
+	udp_v6_flush_pending_frames(sk);
+	release_sock(sk);
+
+	if (static_branch_unlikely(&udpv6_encap_needed_key)) {
+		if (up->encap_type) {
+			void (*encap_destroy)(struct sock *sk);
+			encap_destroy = READ_ONCE(up->encap_destroy);
+			if (encap_destroy)
+				encap_destroy(sk);
+		}
+		if (udp_test_bit(ENCAP_ENABLED, sk)) {
+			static_branch_dec(&udpv6_encap_needed_key);
+			udp_encap_disable();
+		}
+	}
+}
+
+/*
+ *	Socket option code for UDP
+ */
+int udpv6_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
+		     unsigned int optlen)
+{
+	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
+		return udp_lib_setsockopt(sk, level, optname,
+					  optval, optlen,
+					  udp_v6_push_pending_frames);
+	return ipv6_setsockopt(sk, level, optname, optval, optlen);
+}
+
+int udpv6_getsockopt(struct sock *sk, int level, int optname,
+		     char __user *optval, int __user *optlen)
+{
+	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
+		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
+	return ipv6_getsockopt(sk, level, optname, optval, optlen);
+}
+
+static const struct inet6_protocol udpv6_protocol = {
+	.handler	=	udpv6_rcv,
+	.err_handler	=	udpv6_err,
+	.flags		=	INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
+};
+
+/* ------------------------------------------------------------------------ */
+#ifdef CONFIG_PROC_FS
+int udp6_seq_show(struct seq_file *seq, void *v)
+{
+	if (v == SEQ_START_TOKEN) {
+		seq_puts(seq, IPV6_SEQ_DGRAM_HEADER);
+	} else {
+		int bucket = ((struct udp_iter_state *)seq->private)->bucket;
+		struct inet_sock *inet = inet_sk(v);
+		__u16 srcp = ntohs(inet->inet_sport);
+		__u16 destp = ntohs(inet->inet_dport);
+		__ip6_dgram_sock_seq_show(seq, v, srcp, destp,
+					  udp_rqueue_get(v), bucket);
+	}
+	return 0;
+}
+
+const struct seq_operations udp6_seq_ops = {
+	.start		= udp_seq_start,
+	.next		= udp_seq_next,
+	.stop		= udp_seq_stop,
+	.show		= udp6_seq_show,
+};
+EXPORT_SYMBOL(udp6_seq_ops);
+
+static struct udp_seq_afinfo udp6_seq_afinfo = {
+	.family		= AF_INET6,
+	.udp_table	= &udp_table,
+};
+
+int __net_init udp6_proc_init(struct net *net)
+{
+	if (!proc_create_net_data("udp6", 0444, net->proc_net, &udp6_seq_ops,
+			sizeof(struct udp_iter_state), &udp6_seq_afinfo))
+		return -ENOMEM;
+	return 0;
+}
+
+void udp6_proc_exit(struct net *net)
+{
+	remove_proc_entry("udp6", net->proc_net);
+}
+#endif /* CONFIG_PROC_FS */
+
+/* ------------------------------------------------------------------------ */
+
+struct proto udpv6_prot = {
+	.name			= "UDPv6",
+	.owner			= THIS_MODULE,
+	.close			= udp_lib_close,
+	.pre_connect		= udpv6_pre_connect,
+	.connect		= ip6_datagram_connect,
+	.disconnect		= udp_disconnect,
+	.ioctl			= udp_ioctl,
+	.init			= udpv6_init_sock,
+	.destroy		= udpv6_destroy_sock,
+	.setsockopt		= udpv6_setsockopt,
+	.getsockopt		= udpv6_getsockopt,
+	.sendmsg		= udpv6_sendmsg,
+	.recvmsg		= udpv6_recvmsg,
+	.splice_eof		= udpv6_splice_eof,
+	.release_cb		= ip6_datagram_release_cb,
+	.hash			= udp_lib_hash,
+	.unhash			= udp_lib_unhash,
+	.rehash			= udp_v6_rehash,
+	.get_port		= udp_v6_get_port,
+	.put_port		= udp_lib_unhash,
+#ifdef CONFIG_BPF_SYSCALL
+	.psock_update_sk_prot	= udp_bpf_update_proto,
+#endif
+
+	.memory_allocated	= &udp_memory_allocated,
+	.per_cpu_fw_alloc	= &udp_memory_per_cpu_fw_alloc,
+
+	.sysctl_mem		= sysctl_udp_mem,
+	.sysctl_wmem_offset     = offsetof(struct net, ipv4.sysctl_udp_wmem_min),
+	.sysctl_rmem_offset     = offsetof(struct net, ipv4.sysctl_udp_rmem_min),
+	.obj_size		= sizeof(struct udp6_sock),
+	.h.udp_table		= &udp_table,
+	.diag_destroy		= udp_abort,
+};
+
+static struct inet_protosw udpv6_protosw = {
+	.type =      SOCK_DGRAM,
+	.protocol =  IPPROTO_UDP,
+	.prot =      &udpv6_prot,
+	.ops =       &inet6_dgram_ops,
+	.flags =     INET_PROTOSW_PERMANENT,
+};
+
+int __init udpv6_init(void)
+{
+	int ret;
+
+	ret = inet6_add_protocol(&udpv6_protocol, IPPROTO_UDP);
+	if (ret)
+		goto out;
+
+	ret = inet6_register_protosw(&udpv6_protosw);
+	if (ret)
+		goto out_udpv6_protocol;
+out:
+	return ret;
+
+out_udpv6_protocol:
+	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
+	goto out;
+}
+
+void udpv6_exit(void)
+{
+	inet6_unregister_protosw(&udpv6_protosw);
+	inet6_del_protocol(&udpv6_protocol, IPPROTO_UDP);
+}