1 files changed, 280 insertions, 124 deletions

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 86d282618515..dde52b8050b8 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -93,6 +93,7 @@
 #include <linux/inet.h>
 #include <linux/netdevice.h>
 #include <linux/slab.h>
+#include <linux/sock_diag.h>
 #include <net/tcp_states.h>
 #include <linux/skbuff.h>
 #include <linux/proc_fs.h>
@@ -119,15 +120,15 @@
 #if IS_ENABLED(CONFIG_IPV6)
 #include <net/ipv6_stubs.h>
 #endif
+#include <net/rps.h>
 
 struct udp_table udp_table __read_mostly;
-EXPORT_SYMBOL(udp_table);
 
 long sysctl_udp_mem[3] __read_mostly;
-EXPORT_SYMBOL(sysctl_udp_mem);
+EXPORT_IPV6_MOD(sysctl_udp_mem);
 
 atomic_long_t udp_memory_allocated ____cacheline_aligned_in_smp;
-EXPORT_SYMBOL(udp_memory_allocated);
+EXPORT_IPV6_MOD(udp_memory_allocated);
 DEFINE_PER_CPU(int, udp_memory_per_cpu_fw_alloc);
 EXPORT_PER_CPU_SYMBOL_GPL(udp_memory_per_cpu_fw_alloc);
 
@@ -352,7 +353,7 @@ fail_unlock:
 fail:
 	return error;
 }
-EXPORT_SYMBOL(udp_lib_get_port);
+EXPORT_IPV6_MOD(udp_lib_get_port);
 
 int udp_v4_get_port(struct sock *sk, unsigned short snum)
 {
@@ -418,7 +419,50 @@ u32 udp_ehashfn(const struct net *net, const __be32 laddr, const __u16 lport,
 	return __inet_ehashfn(laddr, lport, faddr, fport,
 			      udp_ehash_secret + net_hash_mix(net));
 }
-EXPORT_SYMBOL(udp_ehashfn);
+EXPORT_IPV6_MOD(udp_ehashfn);
+
+/**
+ * udp4_lib_lookup1() - Simplified lookup using primary hash (destination port)
+ * @net:	Network namespace
+ * @saddr:	Source address, network order
+ * @sport:	Source port, network order
+ * @daddr:	Destination address, network order
+ * @hnum:	Destination port, host order
+ * @dif:	Destination interface index
+ * @sdif:	Destination bridge port index, if relevant
+ * @udptable:	Set of UDP hash tables
+ *
+ * Simplified lookup to be used as fallback if no sockets are found due to a
+ * potential race between (receive) address change, and lookup happening before
+ * the rehash operation. This function ignores SO_REUSEPORT groups while scoring
+ * result sockets, because if we have one, we don't need the fallback at all.
+ *
+ * Called under rcu_read_lock().
+ *
+ * Return: socket with highest matching score if any, NULL if none
+ */
+static struct sock *udp4_lib_lookup1(const struct net *net,
+				     __be32 saddr, __be16 sport,
+				     __be32 daddr, unsigned int hnum,
+				     int dif, int sdif,
+				     const struct udp_table *udptable)
+{
+	unsigned int slot = udp_hashfn(net, hnum, udptable->mask);
+	struct udp_hslot *hslot = &udptable->hash[slot];
+	struct sock *sk, *result = NULL;
+	int score, badness = 0;
+
+	sk_for_each_rcu(sk, &hslot->head) {
+		score = compute_score(sk, net,
+				      saddr, sport, daddr, hnum, dif, sdif);
+		if (score > badness) {
+			result = sk;
+			badness = score;
+		}
+	}
+
+	return result;
+}
 
 /* called with rcu_read_lock() */
 static struct sock *udp4_lib_lookup2(const struct net *net,
@@ -610,7 +654,7 @@ void udp_lib_hash4(struct sock *sk, u16 hash)
 
 	spin_unlock_bh(&hslot->lock);
 }
-EXPORT_SYMBOL(udp_lib_hash4);
+EXPORT_IPV6_MOD(udp_lib_hash4);
 
 /* call with sock lock */
 void udp4_hash4(struct sock *sk)
@@ -626,7 +670,7 @@ void udp4_hash4(struct sock *sk)
 
 	udp_lib_hash4(sk, hash);
 }
-EXPORT_SYMBOL(udp4_hash4);
+EXPORT_IPV6_MOD(udp4_hash4);
 #endif /* CONFIG_BASE_SMALL */
 
 /* UDP is nearly always wildcards out the wazoo, it makes no sense to try
@@ -681,6 +725,19 @@ struct sock *__udp4_lib_lookup(const struct net *net, __be32 saddr,
 	result = udp4_lib_lookup2(net, saddr, sport,
 				  htonl(INADDR_ANY), hnum, dif, sdif,
 				  hslot2, skb);
+	if (!IS_ERR_OR_NULL(result))
+		goto done;
+
+	/* Primary hash (destination port) lookup as fallback for this race:
+	 *   1. __ip4_datagram_connect() sets sk_rcv_saddr
+	 *   2. lookup (this function): new sk_rcv_saddr, hashes not updated yet
+	 *   3. rehash operation updating _secondary and four-tuple_ hashes
+	 * The primary hash doesn't need an update after 1., so, thanks to this
+	 * further step, 1. and 3. don't need to be atomic against the lookup.
+	 */
+	result = udp4_lib_lookup1(net, saddr, sport, daddr, hnum, dif, sdif,
+				  udptable);
+
 done:
 	if (IS_ERR(result))
 		return NULL;
@@ -753,11 +810,11 @@ static inline bool __udp_is_mcast_sock(struct net *net, const struct sock *sk,
 }
 
 DEFINE_STATIC_KEY_FALSE(udp_encap_needed_key);
-EXPORT_SYMBOL(udp_encap_needed_key);
+EXPORT_IPV6_MOD(udp_encap_needed_key);
 
 #if IS_ENABLED(CONFIG_IPV6)
 DEFINE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
-EXPORT_SYMBOL(udpv6_encap_needed_key);
+EXPORT_IPV6_MOD(udpv6_encap_needed_key);
 #endif
 
 void udp_encap_enable(void)
@@ -985,7 +1042,7 @@ void udp_flush_pending_frames(struct sock *sk)
 		ip_flush_pending_frames(sk);
 	}
 }
-EXPORT_SYMBOL(udp_flush_pending_frames);
+EXPORT_IPV6_MOD(udp_flush_pending_frames);
 
 /**
  * 	udp4_hwcsum  -  handle outgoing HW checksumming
@@ -1085,9 +1142,9 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4,
 		const int hlen = skb_network_header_len(skb) +
 				 sizeof(struct udphdr);
 
-		if (hlen + cork->gso_size > cork->fragsize) {
+		if (hlen + min(datalen, cork->gso_size) > cork->fragsize) {
 			kfree_skb(skb);
-			return -EINVAL;
+			return -EMSGSIZE;
 		}
 		if (datalen > cork->gso_size * UDP_MAX_SEGMENTS) {
 			kfree_skb(skb);
@@ -1173,7 +1230,7 @@ out:
 	WRITE_ONCE(up->pending, 0);
 	return err;
 }
-EXPORT_SYMBOL(udp_push_pending_frames);
+EXPORT_IPV6_MOD(udp_push_pending_frames);
 
 static int __udp_cmsg_send(struct cmsghdr *cmsg, u16 *gso_size)
 {
@@ -1210,7 +1267,7 @@ int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size)
 
 	return need_ip;
 }
-EXPORT_SYMBOL_GPL(udp_cmsg_send);
+EXPORT_IPV6_MOD_GPL(udp_cmsg_send);
 
 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 {
@@ -1225,7 +1282,7 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 	int free = 0;
 	int connected = 0;
 	__be32 daddr, faddr, saddr;
-	u8 tos, scope;
+	u8 scope;
 	__be16 dport;
 	int err, is_udplite = IS_UDPLITE(sk);
 	int corkreq = udp_test_bit(CORK, sk) || msg->msg_flags & MSG_MORE;
@@ -1349,7 +1406,6 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		faddr = ipc.opt->opt.faddr;
 		connected = 0;
 	}
-	tos = get_rttos(&ipc, inet);
 	scope = ip_sendmsg_scope(inet, &ipc, msg);
 	if (scope == RT_SCOPE_LINK)
 		connected = 0;
@@ -1386,7 +1442,8 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
 		fl4 = &fl4_stack;
 
-		flowi4_init_output(fl4, ipc.oif, ipc.sockc.mark, tos, scope,
+		flowi4_init_output(fl4, ipc.oif, ipc.sockc.mark,
+				   ipc.tos & INET_DSCP_MASK, scope,
 				   sk->sk_protocol, flow_flags, faddr, saddr,
 				   dport, inet->inet_sport, sk->sk_uid);
 
@@ -1505,7 +1562,7 @@ void udp_splice_eof(struct socket *sock)
 		udp_push_pending_frames(sk);
 	release_sock(sk);
 }
-EXPORT_SYMBOL_GPL(udp_splice_eof);
+EXPORT_IPV6_MOD_GPL(udp_splice_eof);
 
 #define UDP_SKB_IS_STATELESS 0x80000000
 
@@ -1570,12 +1627,12 @@ static bool udp_skb_has_head_state(struct sk_buff *skb)
 }
 
 /* fully reclaim rmem/fwd memory allocated for skb */
-static void udp_rmem_release(struct sock *sk, int size, int partial,
-			     bool rx_queue_lock_held)
+static void udp_rmem_release(struct sock *sk, unsigned int size,
+			     int partial, bool rx_queue_lock_held)
 {
 	struct udp_sock *up = udp_sk(sk);
 	struct sk_buff_head *sk_queue;
-	int amt;
+	unsigned int amt;
 
 	if (likely(partial)) {
 		up->forward_deficit += size;
@@ -1595,10 +1652,8 @@ static void udp_rmem_release(struct sock *sk, int size, int partial,
 	if (!rx_queue_lock_held)
 		spin_lock(&sk_queue->lock);
 
-
-	sk_forward_alloc_add(sk, size);
-	amt = (sk->sk_forward_alloc - partial) & ~(PAGE_SIZE - 1);
-	sk_forward_alloc_add(sk, -amt);
+	amt = (size + sk->sk_forward_alloc - partial) & ~(PAGE_SIZE - 1);
+	sk_forward_alloc_add(sk, size - amt);
 
 	if (amt)
 		__sk_mem_reduce_allocated(sk, amt >> PAGE_SHIFT);
@@ -1622,7 +1677,7 @@ void udp_skb_destructor(struct sock *sk, struct sk_buff *skb)
 	prefetch(&skb->data);
 	udp_rmem_release(sk, udp_skb_truesize(skb), 1, false);
 }
-EXPORT_SYMBOL(udp_skb_destructor);
+EXPORT_IPV6_MOD(udp_skb_destructor);
 
 /* as above, but the caller held the rx queue lock, too */
 static void udp_skb_dtor_locked(struct sock *sk, struct sk_buff *skb)
@@ -1670,17 +1725,25 @@ static int udp_rmem_schedule(struct sock *sk, int size)
 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb)
 {
 	struct sk_buff_head *list = &sk->sk_receive_queue;
-	int rmem, err = -ENOMEM;
+	unsigned int rmem, rcvbuf;
 	spinlock_t *busy = NULL;
-	int size, rcvbuf;
+	int size, err = -ENOMEM;
 
-	/* Immediately drop when the receive queue is full.
-	 * Always allow at least one packet.
-	 */
 	rmem = atomic_read(&sk->sk_rmem_alloc);
 	rcvbuf = READ_ONCE(sk->sk_rcvbuf);
-	if (rmem > rcvbuf)
-		goto drop;
+	size = skb->truesize;
+
+	/* Immediately drop when the receive queue is full.
+	 * Cast to unsigned int performs the boundary check for INT_MAX.
+	 */
+	if (rmem + size > rcvbuf) {
+		if (rcvbuf > INT_MAX >> 1)
+			goto drop;
+
+		/* Always allow at least one packet for small buffer. */
+		if (rmem > rcvbuf)
+			goto drop;
+	}
 
 	/* Under mem pressure, it might be helpful to help udp_recvmsg()
 	 * having linear skbs :
@@ -1690,10 +1753,10 @@ int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb)
 	 */
 	if (rmem > (rcvbuf >> 1)) {
 		skb_condense(skb);
-
+		size = skb->truesize;
 		busy = busylock_acquire(sk);
 	}
-	size = skb->truesize;
+
 	udp_set_dev_scratch(skb);
 
 	atomic_add(size, &sk->sk_rmem_alloc);
@@ -1729,7 +1792,7 @@ drop:
 	busylock_release(busy);
 	return err;
 }
-EXPORT_SYMBOL_GPL(__udp_enqueue_schedule_skb);
+EXPORT_IPV6_MOD_GPL(__udp_enqueue_schedule_skb);
 
 void udp_destruct_common(struct sock *sk)
 {
@@ -1745,7 +1808,7 @@ void udp_destruct_common(struct sock *sk)
 	}
 	udp_rmem_release(sk, total, 0, true);
 }
-EXPORT_SYMBOL_GPL(udp_destruct_common);
+EXPORT_IPV6_MOD_GPL(udp_destruct_common);
 
 static void udp_destruct_sock(struct sock *sk)
 {
@@ -1776,11 +1839,11 @@ void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len)
 		skb_release_head_state(skb);
 	__consume_stateless_skb(skb);
 }
-EXPORT_SYMBOL_GPL(skb_consume_udp);
+EXPORT_IPV6_MOD_GPL(skb_consume_udp);
 
 static struct sk_buff *__first_packet_length(struct sock *sk,
 					     struct sk_buff_head *rcvq,
-					     int *total)
+					     unsigned int *total)
 {
 	struct sk_buff *skb;
 
@@ -1793,7 +1856,7 @@ static struct sk_buff *__first_packet_length(struct sock *sk,
 			atomic_inc(&sk->sk_drops);
 			__skb_unlink(skb, rcvq);
 			*total += skb->truesize;
-			kfree_skb(skb);
+			kfree_skb_reason(skb, SKB_DROP_REASON_UDP_CSUM);
 		} else {
 			udp_skb_csum_unnecessary_set(skb);
 			break;
@@ -1813,8 +1876,8 @@ static int first_packet_length(struct sock *sk)
 {
 	struct sk_buff_head *rcvq = &udp_sk(sk)->reader_queue;
 	struct sk_buff_head *sk_queue = &sk->sk_receive_queue;
+	unsigned int total = 0;
 	struct sk_buff *skb;
-	int total = 0;
 	int res;
 
 	spin_lock_bh(&rcvq->lock);
@@ -1858,7 +1921,7 @@ int udp_ioctl(struct sock *sk, int cmd, int *karg)
 
 	return 0;
 }
-EXPORT_SYMBOL(udp_ioctl);
+EXPORT_IPV6_MOD(udp_ioctl);
 
 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
 			       int *off, int *err)
@@ -1881,8 +1944,8 @@ struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
 		error = -EAGAIN;
 		do {
 			spin_lock_bh(&queue->lock);
-			skb = __skb_try_recv_from_queue(sk, queue, flags, off,
-							err, &last);
+			skb = __skb_try_recv_from_queue(queue, flags, off, err,
+							&last);
 			if (skb) {
 				if (!(flags & MSG_PEEK))
 					udp_skb_destructor(sk, skb);
@@ -1903,8 +1966,8 @@ struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
 			spin_lock(&sk_queue->lock);
 			skb_queue_splice_tail_init(sk_queue, queue);
 
-			skb = __skb_try_recv_from_queue(sk, queue, flags, off,
-							err, &last);
+			skb = __skb_try_recv_from_queue(queue, flags, off, err,
+							&last);
 			if (skb && !(flags & MSG_PEEK))
 				udp_skb_dtor_locked(sk, skb);
 			spin_unlock(&sk_queue->lock);
@@ -1947,14 +2010,14 @@ try_again:
 		__UDP_INC_STATS(net, UDP_MIB_CSUMERRORS, is_udplite);
 		__UDP_INC_STATS(net, UDP_MIB_INERRORS, is_udplite);
 		atomic_inc(&sk->sk_drops);
-		kfree_skb(skb);
+		kfree_skb_reason(skb, SKB_DROP_REASON_UDP_CSUM);
 		goto try_again;
 	}
 
 	WARN_ON_ONCE(!skb_set_owner_sk_safe(skb, sk));
 	return recv_actor(sk, skb);
 }
-EXPORT_SYMBOL(udp_read_skb);
+EXPORT_IPV6_MOD(udp_read_skb);
 
 /*
  * 	This should be easy, if there is something there we
@@ -2062,7 +2125,7 @@ csum_copy_err:
 		UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
 		UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
 	}
-	kfree_skb(skb);
+	kfree_skb_reason(skb, SKB_DROP_REASON_UDP_CSUM);
 
 	/* starting over for a new packet, but check if we need to yield */
 	cond_resched();
@@ -2081,7 +2144,7 @@ int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 
 	return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr, &addr_len);
 }
-EXPORT_SYMBOL(udp_pre_connect);
+EXPORT_IPV6_MOD(udp_pre_connect);
 
 static int udp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 {
@@ -2130,7 +2193,7 @@ int udp_disconnect(struct sock *sk, int flags)
 	release_sock(sk);
 	return 0;
 }
-EXPORT_SYMBOL(udp_disconnect);
+EXPORT_IPV6_MOD(udp_disconnect);
 
 void udp_lib_unhash(struct sock *sk)
 {
@@ -2138,6 +2201,7 @@ void udp_lib_unhash(struct sock *sk)
 		struct udp_table *udptable = udp_get_table_prot(sk);
 		struct udp_hslot *hslot, *hslot2;
 
+		sock_rps_delete_flow(sk);
 		hslot  = udp_hashslot(udptable, sock_net(sk),
 				      udp_sk(sk)->udp_port_hash);
 		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
@@ -2160,7 +2224,7 @@ void udp_lib_unhash(struct sock *sk)
 		spin_unlock_bh(&hslot->lock);
 	}
 }
-EXPORT_SYMBOL(udp_lib_unhash);
+EXPORT_IPV6_MOD(udp_lib_unhash);
 
 /*
  * inet_rcv_saddr was changed, we must rehash secondary hash
@@ -2224,7 +2288,7 @@ void udp_lib_rehash(struct sock *sk, u16 newhash, u16 newhash4)
 		}
 	}
 }
-EXPORT_SYMBOL(udp_lib_rehash);
+EXPORT_IPV6_MOD(udp_lib_rehash);
 
 void udp_v4_rehash(struct sock *sk)
 {
@@ -2429,7 +2493,7 @@ bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
 	}
 	return false;
 }
-EXPORT_SYMBOL(udp_sk_rx_dst_set);
+EXPORT_IPV6_MOD(udp_sk_rx_dst_set);
 
 /*
  *	Multicasts and broadcasts go to each listener.
@@ -2836,20 +2900,40 @@ void udp_destroy_sock(struct sock *sk)
 			if (encap_destroy)
 				encap_destroy(sk);
 		}
-		if (udp_test_bit(ENCAP_ENABLED, sk))
+		if (udp_test_bit(ENCAP_ENABLED, sk)) {
 			static_branch_dec(&udp_encap_needed_key);
+			udp_tunnel_cleanup_gro(sk);
+		}
 	}
 }
 
+typedef struct sk_buff *(*udp_gro_receive_t)(struct sock *sk,
+					     struct list_head *head,
+					     struct sk_buff *skb);
+
 static void set_xfrm_gro_udp_encap_rcv(__u16 encap_type, unsigned short family,
 				       struct sock *sk)
 {
 #ifdef CONFIG_XFRM
+	udp_gro_receive_t new_gro_receive;
+
 	if (udp_test_bit(GRO_ENABLED, sk) && encap_type == UDP_ENCAP_ESPINUDP) {
-		if (family == AF_INET)
-			WRITE_ONCE(udp_sk(sk)->gro_receive, xfrm4_gro_udp_encap_rcv);
-		else if (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6)
-			WRITE_ONCE(udp_sk(sk)->gro_receive, ipv6_stub->xfrm6_gro_udp_encap_rcv);
+		if (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6)
+			new_gro_receive = ipv6_stub->xfrm6_gro_udp_encap_rcv;
+		else
+			new_gro_receive = xfrm4_gro_udp_encap_rcv;
+
+		if (udp_sk(sk)->gro_receive != new_gro_receive) {
+			/*
+			 * With IPV6_ADDRFORM the gro callback could change
+			 * after being set, unregister the old one, if valid.
+			 */
+			if (udp_sk(sk)->gro_receive)
+				udp_tunnel_update_gro_rcv(sk, false);
+
+			WRITE_ONCE(udp_sk(sk)->gro_receive, new_gro_receive);
+			udp_tunnel_update_gro_rcv(sk, true);
+		}
 	}
 #endif
 }
@@ -2899,6 +2983,7 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
 		break;
 
 	case UDP_ENCAP:
+		sockopt_lock_sock(sk);
 		switch (val) {
 		case 0:
 #ifdef CONFIG_XFRM
@@ -2922,6 +3007,7 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
 			err = -ENOPROTOOPT;
 			break;
 		}
+		sockopt_release_sock(sk);
 		break;
 
 	case UDP_NO_CHECK6_TX:
@@ -2939,13 +3025,14 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
 		break;
 
 	case UDP_GRO:
-
+		sockopt_lock_sock(sk);
 		/* when enabling GRO, accept the related GSO packet type */
 		if (valbool)
 			udp_tunnel_encap_enable(sk);
 		udp_assign_bit(GRO_ENABLED, sk, valbool);
 		udp_assign_bit(ACCEPT_L4, sk, valbool);
 		set_xfrm_gro_udp_encap_rcv(up->encap_type, sk->sk_family, sk);
+		sockopt_release_sock(sk);
 		break;
 
 	/*
@@ -2985,7 +3072,7 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
 
 	return err;
 }
-EXPORT_SYMBOL(udp_lib_setsockopt);
+EXPORT_IPV6_MOD(udp_lib_setsockopt);
 
 int udp_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
 		   unsigned int optlen)
@@ -3056,7 +3143,7 @@ int udp_lib_getsockopt(struct sock *sk, int level, int optname,
 		return -EFAULT;
 	return 0;
 }
-EXPORT_SYMBOL(udp_lib_getsockopt);
+EXPORT_IPV6_MOD(udp_lib_getsockopt);
 
 int udp_getsockopt(struct sock *sk, int level, int optname,
 		   char __user *optval, int __user *optlen)
@@ -3098,7 +3185,7 @@ __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait)
 	return mask;
 
 }
-EXPORT_SYMBOL(udp_poll);
+EXPORT_IPV6_MOD(udp_poll);
 
 int udp_abort(struct sock *sk, int err)
 {
@@ -3121,7 +3208,7 @@ out:
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(udp_abort);
+EXPORT_IPV6_MOD_GPL(udp_abort);
 
 struct proto udp_prot = {
 	.name			= "UDP",
@@ -3255,7 +3342,7 @@ void *udp_seq_start(struct seq_file *seq, loff_t *pos)
 
 	return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
 }
-EXPORT_SYMBOL(udp_seq_start);
+EXPORT_IPV6_MOD(udp_seq_start);
 
 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
@@ -3269,7 +3356,7 @@ void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 	++*pos;
 	return sk;
 }
-EXPORT_SYMBOL(udp_seq_next);
+EXPORT_IPV6_MOD(udp_seq_next);
 
 void udp_seq_stop(struct seq_file *seq, void *v)
 {
@@ -3281,7 +3368,7 @@ void udp_seq_stop(struct seq_file *seq, void *v)
 	if (state->bucket <= udptable->mask)
 		spin_unlock_bh(&udptable->hash[state->bucket].lock);
 }
-EXPORT_SYMBOL(udp_seq_stop);
+EXPORT_IPV6_MOD(udp_seq_stop);
 
 /* ------------------------------------------------------------------------ */
 static void udp4_format_sock(struct sock *sp, struct seq_file *f,
@@ -3329,34 +3416,55 @@ struct bpf_iter__udp {
 	int bucket __aligned(8);
 };
 
+union bpf_udp_iter_batch_item {
+	struct sock *sk;
+	__u64 cookie;
+};
+
 struct bpf_udp_iter_state {
 	struct udp_iter_state state;
 	unsigned int cur_sk;
 	unsigned int end_sk;
 	unsigned int max_sk;
-	int offset;
-	struct sock **batch;
-	bool st_bucket_done;
+	union bpf_udp_iter_batch_item *batch;
 };
 
 static int bpf_iter_udp_realloc_batch(struct bpf_udp_iter_state *iter,
-				      unsigned int new_batch_sz);
+				      unsigned int new_batch_sz, gfp_t flags);
+static struct sock *bpf_iter_udp_resume(struct sock *first_sk,
+					union bpf_udp_iter_batch_item *cookies,
+					int n_cookies)
+{
+	struct sock *sk = NULL;
+	int i;
+
+	for (i = 0; i < n_cookies; i++) {
+		sk = first_sk;
+		udp_portaddr_for_each_entry_from(sk)
+			if (cookies[i].cookie == atomic64_read(&sk->sk_cookie))
+				goto done;
+	}
+done:
+	return sk;
+}
+
 static struct sock *bpf_iter_udp_batch(struct seq_file *seq)
 {
 	struct bpf_udp_iter_state *iter = seq->private;
 	struct udp_iter_state *state = &iter->state;
+	unsigned int find_cookie, end_cookie;
 	struct net *net = seq_file_net(seq);
-	int resume_bucket, resume_offset;
 	struct udp_table *udptable;
 	unsigned int batch_sks = 0;
-	bool resized = false;
+	int resume_bucket;
+	int resizes = 0;
 	struct sock *sk;
+	int err = 0;
 
 	resume_bucket = state->bucket;
-	resume_offset = iter->offset;
 
 	/* The current batch is done, so advance the bucket. */
-	if (iter->st_bucket_done)
+	if (iter->cur_sk == iter->end_sk)
 		state->bucket++;
 
 	udptable = udp_get_table_seq(seq, net);
@@ -3369,62 +3477,89 @@ again:
 	 * before releasing the bucket lock. This allows BPF programs that are
 	 * called in seq_show to acquire the bucket lock if needed.
 	 */
+	find_cookie = iter->cur_sk;
+	end_cookie = iter->end_sk;
 	iter->cur_sk = 0;
 	iter->end_sk = 0;
-	iter->st_bucket_done = false;
 	batch_sks = 0;
 
 	for (; state->bucket <= udptable->mask; state->bucket++) {
 		struct udp_hslot *hslot2 = &udptable->hash2[state->bucket].hslot;
 
 		if (hlist_empty(&hslot2->head))
-			continue;
+			goto next_bucket;
 
-		iter->offset = 0;
 		spin_lock_bh(&hslot2->lock);
-		udp_portaddr_for_each_entry(sk, &hslot2->head) {
+		sk = hlist_entry_safe(hslot2->head.first, struct sock,
+				      __sk_common.skc_portaddr_node);
+		/* Resume from the first (in iteration order) unseen socket from
+		 * the last batch that still exists in resume_bucket. Most of
+		 * the time this will just be where the last iteration left off
+		 * in resume_bucket unless that socket disappeared between
+		 * reads.
+		 */
+		if (state->bucket == resume_bucket)
+			sk = bpf_iter_udp_resume(sk, &iter->batch[find_cookie],
+						 end_cookie - find_cookie);
+fill_batch:
+		udp_portaddr_for_each_entry_from(sk) {
 			if (seq_sk_match(seq, sk)) {
-				/* Resume from the last iterated socket at the
-				 * offset in the bucket before iterator was stopped.
-				 */
-				if (state->bucket == resume_bucket &&
-				    iter->offset < resume_offset) {
-					++iter->offset;
-					continue;
-				}
 				if (iter->end_sk < iter->max_sk) {
 					sock_hold(sk);
-					iter->batch[iter->end_sk++] = sk;
+					iter->batch[iter->end_sk++].sk = sk;
 				}
 				batch_sks++;
 			}
 		}
+
+		/* Allocate a larger batch and try again. */
+		if (unlikely(resizes <= 1 && iter->end_sk &&
+			     iter->end_sk != batch_sks)) {
+			resizes++;
+
+			/* First, try with GFP_USER to maximize the chances of
+			 * grabbing more memory.
+			 */
+			if (resizes == 1) {
+				spin_unlock_bh(&hslot2->lock);
+				err = bpf_iter_udp_realloc_batch(iter,
+								 batch_sks * 3 / 2,
+								 GFP_USER);
+				if (err)
+					return ERR_PTR(err);
+				/* Start over. */
+				goto again;
+			}
+
+			/* Next, hold onto the lock, so the bucket doesn't
+			 * change while we get the rest of the sockets.
+			 */
+			err = bpf_iter_udp_realloc_batch(iter, batch_sks,
+							 GFP_NOWAIT);
+			if (err) {
+				spin_unlock_bh(&hslot2->lock);
+				return ERR_PTR(err);
+			}
+
+			/* Pick up where we left off. */
+			sk = iter->batch[iter->end_sk - 1].sk;
+			sk = hlist_entry_safe(sk->__sk_common.skc_portaddr_node.next,
+					      struct sock,
+					      __sk_common.skc_portaddr_node);
+			batch_sks = iter->end_sk;
+			goto fill_batch;
+		}
+
 		spin_unlock_bh(&hslot2->lock);
 
 		if (iter->end_sk)
 			break;
+next_bucket:
+		resizes = 0;
 	}
 
-	/* All done: no batch made. */
-	if (!iter->end_sk)
-		return NULL;
-
-	if (iter->end_sk == batch_sks) {
-		/* Batching is done for the current bucket; return the first
-		 * socket to be iterated from the batch.
-		 */
-		iter->st_bucket_done = true;
-		goto done;
-	}
-	if (!resized && !bpf_iter_udp_realloc_batch(iter, batch_sks * 3 / 2)) {
-		resized = true;
-		/* After allocating a larger batch, retry one more time to grab
-		 * the whole bucket.
-		 */
-		goto again;
-	}
-done:
-	return iter->batch[0];
+	WARN_ON_ONCE(iter->end_sk != batch_sks);
+	return iter->end_sk ? iter->batch[0].sk : NULL;
 }
 
 static void *bpf_iter_udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
@@ -3435,16 +3570,14 @@ static void *bpf_iter_udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 	/* Whenever seq_next() is called, the iter->cur_sk is
 	 * done with seq_show(), so unref the iter->cur_sk.
 	 */
-	if (iter->cur_sk < iter->end_sk) {
-		sock_put(iter->batch[iter->cur_sk++]);
-		++iter->offset;
-	}
+	if (iter->cur_sk < iter->end_sk)
+		sock_put(iter->batch[iter->cur_sk++].sk);
 
 	/* After updating iter->cur_sk, check if there are more sockets
 	 * available in the current bucket batch.
 	 */
 	if (iter->cur_sk < iter->end_sk)
-		sk = iter->batch[iter->cur_sk];
+		sk = iter->batch[iter->cur_sk].sk;
 	else
 		/* Prepare a new batch. */
 		sk = bpf_iter_udp_batch(seq);
@@ -3508,8 +3641,19 @@ unlock:
 
 static void bpf_iter_udp_put_batch(struct bpf_udp_iter_state *iter)
 {
-	while (iter->cur_sk < iter->end_sk)
-		sock_put(iter->batch[iter->cur_sk++]);
+	union bpf_udp_iter_batch_item *item;
+	unsigned int cur_sk = iter->cur_sk;
+	__u64 cookie;
+
+	/* Remember the cookies of the sockets we haven't seen yet, so we can
+	 * pick up where we left off next time around.
+	 */
+	while (cur_sk < iter->end_sk) {
+		item = &iter->batch[cur_sk++];
+		cookie = sock_gen_cookie(item->sk);
+		sock_put(item->sk);
+		item->cookie = cookie;
+	}
 }
 
 static void bpf_iter_udp_seq_stop(struct seq_file *seq, void *v)
@@ -3525,10 +3669,8 @@ static void bpf_iter_udp_seq_stop(struct seq_file *seq, void *v)
 			(void)udp_prog_seq_show(prog, &meta, v, 0, 0);
 	}
 
-	if (iter->cur_sk < iter->end_sk) {
+	if (iter->cur_sk < iter->end_sk)
 		bpf_iter_udp_put_batch(iter);
-		iter->st_bucket_done = false;
-	}
 }
 
 static const struct seq_operations bpf_iter_udp_seq_ops = {
@@ -3560,7 +3702,7 @@ const struct seq_operations udp_seq_ops = {
 	.stop		= udp_seq_stop,
 	.show		= udp4_seq_show,
 };
-EXPORT_SYMBOL(udp_seq_ops);
+EXPORT_IPV6_MOD(udp_seq_ops);
 
 static struct udp_seq_afinfo udp4_seq_afinfo = {
 	.family		= AF_INET,
@@ -3749,6 +3891,15 @@ fallback:
 
 static int __net_init udp_pernet_init(struct net *net)
 {
+#if IS_ENABLED(CONFIG_NET_UDP_TUNNEL)
+	int i;
+
+	/* No tunnel is configured */
+	for (i = 0; i < ARRAY_SIZE(net->ipv4.udp_tunnel_gro); ++i) {
+		INIT_HLIST_HEAD(&net->ipv4.udp_tunnel_gro[i].list);
+		RCU_INIT_POINTER(net->ipv4.udp_tunnel_gro[i].sk, NULL);
+	}
+#endif
 	udp_sysctl_init(net);
 	udp_set_table(net);
 
@@ -3770,16 +3921,19 @@ DEFINE_BPF_ITER_FUNC(udp, struct bpf_iter_meta *meta,
 		     struct udp_sock *udp_sk, uid_t uid, int bucket)
 
 static int bpf_iter_udp_realloc_batch(struct bpf_udp_iter_state *iter,
-				      unsigned int new_batch_sz)
+				      unsigned int new_batch_sz, gfp_t flags)
 {
-	struct sock **new_batch;
+	union bpf_udp_iter_batch_item *new_batch;
 
 	new_batch = kvmalloc_array(new_batch_sz, sizeof(*new_batch),
-				   GFP_USER | __GFP_NOWARN);
+				   flags | __GFP_NOWARN);
 	if (!new_batch)
 		return -ENOMEM;
 
-	bpf_iter_udp_put_batch(iter);
+	if (flags != GFP_NOWAIT)
+		bpf_iter_udp_put_batch(iter);
+
+	memcpy(new_batch, iter->batch, sizeof(*iter->batch) * iter->end_sk);
 	kvfree(iter->batch);
 	iter->batch = new_batch;
 	iter->max_sk = new_batch_sz;
@@ -3798,10 +3952,12 @@ static int bpf_iter_init_udp(void *priv_data, struct bpf_iter_aux_info *aux)
 	if (ret)
 		return ret;
 
-	ret = bpf_iter_udp_realloc_batch(iter, INIT_BATCH_SZ);
+	ret = bpf_iter_udp_realloc_batch(iter, INIT_BATCH_SZ, GFP_USER);
 	if (ret)
 		bpf_iter_fini_seq_net(priv_data);
 
+	iter->state.bucket = -1;
+
 	return ret;
 }