1 files changed, 668 insertions, 0 deletions

diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
new file mode 100644
index 000000000000..b7918d4caa30
--- /dev/null
+++ b/net/ipv4/tcp_bpf.c
@@ -0,0 +1,668 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */
+
+#include <linux/skmsg.h>
+#include <linux/filter.h>
+#include <linux/bpf.h>
+#include <linux/init.h>
+#include <linux/wait.h>
+
+#include <net/inet_common.h>
+
+static bool tcp_bpf_stream_read(const struct sock *sk)
+{
+	struct sk_psock *psock;
+	bool empty = true;
+
+	rcu_read_lock();
+	psock = sk_psock(sk);
+	if (likely(psock))
+		empty = list_empty(&psock->ingress_msg);
+	rcu_read_unlock();
+	return !empty;
+}
+
+static int tcp_bpf_wait_data(struct sock *sk, struct sk_psock *psock,
+			     int flags, long timeo, int *err)
+{
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
+	int ret;
+
+	add_wait_queue(sk_sleep(sk), &wait);
+	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+	ret = sk_wait_event(sk, &timeo,
+			    !list_empty(&psock->ingress_msg) ||
+			    !skb_queue_empty(&sk->sk_receive_queue), &wait);
+	sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
+	remove_wait_queue(sk_sleep(sk), &wait);
+	return ret;
+}
+
+int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock,
+		      struct msghdr *msg, int len, int flags)
+{
+	struct iov_iter *iter = &msg->msg_iter;
+	int peek = flags & MSG_PEEK;
+	int i, ret, copied = 0;
+	struct sk_msg *msg_rx;
+
+	msg_rx = list_first_entry_or_null(&psock->ingress_msg,
+					  struct sk_msg, list);
+
+	while (copied != len) {
+		struct scatterlist *sge;
+
+		if (unlikely(!msg_rx))
+			break;
+
+		i = msg_rx->sg.start;
+		do {
+			struct page *page;
+			int copy;
+
+			sge = sk_msg_elem(msg_rx, i);
+			copy = sge->length;
+			page = sg_page(sge);
+			if (copied + copy > len)
+				copy = len - copied;
+			ret = copy_page_to_iter(page, sge->offset, copy, iter);
+			if (ret != copy) {
+				msg_rx->sg.start = i;
+				return -EFAULT;
+			}
+
+			copied += copy;
+			if (likely(!peek)) {
+				sge->offset += copy;
+				sge->length -= copy;
+				sk_mem_uncharge(sk, copy);
+				msg_rx->sg.size -= copy;
+
+				if (!sge->length) {
+					sk_msg_iter_var_next(i);
+					if (!msg_rx->skb)
+						put_page(page);
+				}
+			} else {
+				sk_msg_iter_var_next(i);
+			}
+
+			if (copied == len)
+				break;
+		} while (i != msg_rx->sg.end);
+
+		if (unlikely(peek)) {
+			msg_rx = list_next_entry(msg_rx, list);
+			continue;
+		}
+
+		msg_rx->sg.start = i;
+		if (!sge->length && msg_rx->sg.start == msg_rx->sg.end) {
+			list_del(&msg_rx->list);
+			if (msg_rx->skb)
+				consume_skb(msg_rx->skb);
+			kfree(msg_rx);
+		}
+		msg_rx = list_first_entry_or_null(&psock->ingress_msg,
+						  struct sk_msg, list);
+	}
+
+	return copied;
+}
+EXPORT_SYMBOL_GPL(__tcp_bpf_recvmsg);
+
+int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
+		    int nonblock, int flags, int *addr_len)
+{
+	struct sk_psock *psock;
+	int copied, ret;
+
+	if (unlikely(flags & MSG_ERRQUEUE))
+		return inet_recv_error(sk, msg, len, addr_len);
+	if (!skb_queue_empty(&sk->sk_receive_queue))
+		return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
+
+	psock = sk_psock_get(sk);
+	if (unlikely(!psock))
+		return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
+	lock_sock(sk);
+msg_bytes_ready:
+	copied = __tcp_bpf_recvmsg(sk, psock, msg, len, flags);
+	if (!copied) {
+		int data, err = 0;
+		long timeo;
+
+		timeo = sock_rcvtimeo(sk, nonblock);
+		data = tcp_bpf_wait_data(sk, psock, flags, timeo, &err);
+		if (data) {
+			if (skb_queue_empty(&sk->sk_receive_queue))
+				goto msg_bytes_ready;
+			release_sock(sk);
+			sk_psock_put(sk, psock);
+			return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len);
+		}
+		if (err) {
+			ret = err;
+			goto out;
+		}
+	}
+	ret = copied;
+out:
+	release_sock(sk);
+	sk_psock_put(sk, psock);
+	return ret;
+}
+
+static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock,
+			   struct sk_msg *msg, u32 apply_bytes, int flags)
+{
+	bool apply = apply_bytes;
+	struct scatterlist *sge;
+	u32 size, copied = 0;
+	struct sk_msg *tmp;
+	int i, ret = 0;
+
+	tmp = kzalloc(sizeof(*tmp), __GFP_NOWARN | GFP_KERNEL);
+	if (unlikely(!tmp))
+		return -ENOMEM;
+
+	lock_sock(sk);
+	tmp->sg.start = msg->sg.start;
+	i = msg->sg.start;
+	do {
+		sge = sk_msg_elem(msg, i);
+		size = (apply && apply_bytes < sge->length) ?
+			apply_bytes : sge->length;
+		if (!sk_wmem_schedule(sk, size)) {
+			if (!copied)
+				ret = -ENOMEM;
+			break;
+		}
+
+		sk_mem_charge(sk, size);
+		sk_msg_xfer(tmp, msg, i, size);
+		copied += size;
+		if (sge->length)
+			get_page(sk_msg_page(tmp, i));
+		sk_msg_iter_var_next(i);
+		tmp->sg.end = i;
+		if (apply) {
+			apply_bytes -= size;
+			if (!apply_bytes)
+				break;
+		}
+	} while (i != msg->sg.end);
+
+	if (!ret) {
+		msg->sg.start = i;
+		msg->sg.size -= apply_bytes;
+		sk_psock_queue_msg(psock, tmp);
+		sk->sk_data_ready(sk);
+	} else {
+		sk_msg_free(sk, tmp);
+		kfree(tmp);
+	}
+
+	release_sock(sk);
+	return ret;
+}
+
+static int tcp_bpf_push(struct sock *sk, struct sk_msg *msg, u32 apply_bytes,
+			int flags, bool uncharge)
+{
+	bool apply = apply_bytes;
+	struct scatterlist *sge;
+	struct page *page;
+	int size, ret = 0;
+	u32 off;
+
+	while (1) {
+		sge = sk_msg_elem(msg, msg->sg.start);
+		size = (apply && apply_bytes < sge->length) ?
+			apply_bytes : sge->length;
+		off  = sge->offset;
+		page = sg_page(sge);
+
+		tcp_rate_check_app_limited(sk);
+retry:
+		ret = do_tcp_sendpages(sk, page, off, size, flags);
+		if (ret <= 0)
+			return ret;
+		if (apply)
+			apply_bytes -= ret;
+		msg->sg.size -= ret;
+		sge->offset += ret;
+		sge->length -= ret;
+		if (uncharge)
+			sk_mem_uncharge(sk, ret);
+		if (ret != size) {
+			size -= ret;
+			off  += ret;
+			goto retry;
+		}
+		if (!sge->length) {
+			put_page(page);
+			sk_msg_iter_next(msg, start);
+			sg_init_table(sge, 1);
+			if (msg->sg.start == msg->sg.end)
+				break;
+		}
+		if (apply && !apply_bytes)
+			break;
+	}
+
+	return 0;
+}
+
+static int tcp_bpf_push_locked(struct sock *sk, struct sk_msg *msg,
+			       u32 apply_bytes, int flags, bool uncharge)
+{
+	int ret;
+
+	lock_sock(sk);
+	ret = tcp_bpf_push(sk, msg, apply_bytes, flags, uncharge);
+	release_sock(sk);
+	return ret;
+}
+
+int tcp_bpf_sendmsg_redir(struct sock *sk, struct sk_msg *msg,
+			  u32 bytes, int flags)
+{
+	bool ingress = sk_msg_to_ingress(msg);
+	struct sk_psock *psock = sk_psock_get(sk);
+	int ret;
+
+	if (unlikely(!psock)) {
+		sk_msg_free(sk, msg);
+		return 0;
+	}
+	ret = ingress ? bpf_tcp_ingress(sk, psock, msg, bytes, flags) :
+			tcp_bpf_push_locked(sk, msg, bytes, flags, false);
+	sk_psock_put(sk, psock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tcp_bpf_sendmsg_redir);
+
+static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock,
+				struct sk_msg *msg, int *copied, int flags)
+{
+	bool cork = false, enospc = msg->sg.start == msg->sg.end;
+	struct sock *sk_redir;
+	u32 tosend;
+	int ret;
+
+more_data:
+	if (psock->eval == __SK_NONE)
+		psock->eval = sk_psock_msg_verdict(sk, psock, msg);
+
+	if (msg->cork_bytes &&
+	    msg->cork_bytes > msg->sg.size && !enospc) {
+		psock->cork_bytes = msg->cork_bytes - msg->sg.size;
+		if (!psock->cork) {
+			psock->cork = kzalloc(sizeof(*psock->cork),
+					      GFP_ATOMIC | __GFP_NOWARN);
+			if (!psock->cork)
+				return -ENOMEM;
+		}
+		memcpy(psock->cork, msg, sizeof(*msg));
+		return 0;
+	}
+
+	tosend = msg->sg.size;
+	if (psock->apply_bytes && psock->apply_bytes < tosend)
+		tosend = psock->apply_bytes;
+
+	switch (psock->eval) {
+	case __SK_PASS:
+		ret = tcp_bpf_push(sk, msg, tosend, flags, true);
+		if (unlikely(ret)) {
+			*copied -= sk_msg_free(sk, msg);
+			break;
+		}
+		sk_msg_apply_bytes(psock, tosend);
+		break;
+	case __SK_REDIRECT:
+		sk_redir = psock->sk_redir;
+		sk_msg_apply_bytes(psock, tosend);
+		if (psock->cork) {
+			cork = true;
+			psock->cork = NULL;
+		}
+		sk_msg_return(sk, msg, tosend);
+		release_sock(sk);
+		ret = tcp_bpf_sendmsg_redir(sk_redir, msg, tosend, flags);
+		lock_sock(sk);
+		if (unlikely(ret < 0)) {
+			int free = sk_msg_free_nocharge(sk, msg);
+
+			if (!cork)
+				*copied -= free;
+		}
+		if (cork) {
+			sk_msg_free(sk, msg);
+			kfree(msg);
+			msg = NULL;
+			ret = 0;
+		}
+		break;
+	case __SK_DROP:
+	default:
+		sk_msg_free_partial(sk, msg, tosend);
+		sk_msg_apply_bytes(psock, tosend);
+		*copied -= tosend;
+		return -EACCES;
+	}
+
+	if (likely(!ret)) {
+		if (!psock->apply_bytes) {
+			psock->eval =  __SK_NONE;
+			if (psock->sk_redir) {
+				sock_put(psock->sk_redir);
+				psock->sk_redir = NULL;
+			}
+		}
+		if (msg &&
+		    msg->sg.data[msg->sg.start].page_link &&
+		    msg->sg.data[msg->sg.start].length)
+			goto more_data;
+	}
+	return ret;
+}
+
+static int tcp_bpf_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
+{
+	struct sk_msg tmp, *msg_tx = NULL;
+	int flags = msg->msg_flags | MSG_NO_SHARED_FRAGS;
+	int copied = 0, err = 0;
+	struct sk_psock *psock;
+	long timeo;
+
+	psock = sk_psock_get(sk);
+	if (unlikely(!psock))
+		return tcp_sendmsg(sk, msg, size);
+
+	lock_sock(sk);
+	timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
+	while (msg_data_left(msg)) {
+		bool enospc = false;
+		u32 copy, osize;
+
+		if (sk->sk_err) {
+			err = -sk->sk_err;
+			goto out_err;
+		}
+
+		copy = msg_data_left(msg);
+		if (!sk_stream_memory_free(sk))
+			goto wait_for_sndbuf;
+		if (psock->cork) {
+			msg_tx = psock->cork;
+		} else {
+			msg_tx = &tmp;
+			sk_msg_init(msg_tx);
+		}
+
+		osize = msg_tx->sg.size;
+		err = sk_msg_alloc(sk, msg_tx, msg_tx->sg.size + copy, msg_tx->sg.end - 1);
+		if (err) {
+			if (err != -ENOSPC)
+				goto wait_for_memory;
+			enospc = true;
+			copy = msg_tx->sg.size - osize;
+		}
+
+		err = sk_msg_memcopy_from_iter(sk, &msg->msg_iter, msg_tx,
+					       copy);
+		if (err < 0) {
+			sk_msg_trim(sk, msg_tx, osize);
+			goto out_err;
+		}
+
+		copied += copy;
+		if (psock->cork_bytes) {
+			if (size > psock->cork_bytes)
+				psock->cork_bytes = 0;
+			else
+				psock->cork_bytes -= size;
+			if (psock->cork_bytes && !enospc)
+				goto out_err;
+			/* All cork bytes are accounted, rerun the prog. */
+			psock->eval = __SK_NONE;
+			psock->cork_bytes = 0;
+		}
+
+		err = tcp_bpf_send_verdict(sk, psock, msg_tx, &copied, flags);
+		if (unlikely(err < 0))
+			goto out_err;
+		continue;
+wait_for_sndbuf:
+		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+wait_for_memory:
+		err = sk_stream_wait_memory(sk, &timeo);
+		if (err) {
+			if (msg_tx && msg_tx != psock->cork)
+				sk_msg_free(sk, msg_tx);
+			goto out_err;
+		}
+	}
+out_err:
+	if (err < 0)
+		err = sk_stream_error(sk, msg->msg_flags, err);
+	release_sock(sk);
+	sk_psock_put(sk, psock);
+	return copied ? copied : err;
+}
+
+static int tcp_bpf_sendpage(struct sock *sk, struct page *page, int offset,
+			    size_t size, int flags)
+{
+	struct sk_msg tmp, *msg = NULL;
+	int err = 0, copied = 0;
+	struct sk_psock *psock;
+	bool enospc = false;
+
+	psock = sk_psock_get(sk);
+	if (unlikely(!psock))
+		return tcp_sendpage(sk, page, offset, size, flags);
+
+	lock_sock(sk);
+	if (psock->cork) {
+		msg = psock->cork;
+	} else {
+		msg = &tmp;
+		sk_msg_init(msg);
+	}
+
+	/* Catch case where ring is full and sendpage is stalled. */
+	if (unlikely(sk_msg_full(msg)))
+		goto out_err;
+
+	sk_msg_page_add(msg, page, size, offset);
+	sk_mem_charge(sk, size);
+	copied = size;
+	if (sk_msg_full(msg))
+		enospc = true;
+	if (psock->cork_bytes) {
+		if (size > psock->cork_bytes)
+			psock->cork_bytes = 0;
+		else
+			psock->cork_bytes -= size;
+		if (psock->cork_bytes && !enospc)
+			goto out_err;
+		/* All cork bytes are accounted, rerun the prog. */
+		psock->eval = __SK_NONE;
+		psock->cork_bytes = 0;
+	}
+
+	err = tcp_bpf_send_verdict(sk, psock, msg, &copied, flags);
+out_err:
+	release_sock(sk);
+	sk_psock_put(sk, psock);
+	return copied ? copied : err;
+}
+
+static void tcp_bpf_remove(struct sock *sk, struct sk_psock *psock)
+{
+	struct sk_psock_link *link;
+
+	sk_psock_cork_free(psock);
+	__sk_psock_purge_ingress_msg(psock);
+	while ((link = sk_psock_link_pop(psock))) {
+		sk_psock_unlink(sk, link);
+		sk_psock_free_link(link);
+	}
+}
+
+static void tcp_bpf_unhash(struct sock *sk)
+{
+	void (*saved_unhash)(struct sock *sk);
+	struct sk_psock *psock;
+
+	rcu_read_lock();
+	psock = sk_psock(sk);
+	if (unlikely(!psock)) {
+		rcu_read_unlock();
+		if (sk->sk_prot->unhash)
+			sk->sk_prot->unhash(sk);
+		return;
+	}
+
+	saved_unhash = psock->saved_unhash;
+	tcp_bpf_remove(sk, psock);
+	rcu_read_unlock();
+	saved_unhash(sk);
+}
+
+static void tcp_bpf_close(struct sock *sk, long timeout)
+{
+	void (*saved_close)(struct sock *sk, long timeout);
+	struct sk_psock *psock;
+
+	lock_sock(sk);
+	rcu_read_lock();
+	psock = sk_psock(sk);
+	if (unlikely(!psock)) {
+		rcu_read_unlock();
+		release_sock(sk);
+		return sk->sk_prot->close(sk, timeout);
+	}
+
+	saved_close = psock->saved_close;
+	tcp_bpf_remove(sk, psock);
+	rcu_read_unlock();
+	release_sock(sk);
+	saved_close(sk, timeout);
+}
+
+enum {
+	TCP_BPF_IPV4,
+	TCP_BPF_IPV6,
+	TCP_BPF_NUM_PROTS,
+};
+
+enum {
+	TCP_BPF_BASE,
+	TCP_BPF_TX,
+	TCP_BPF_NUM_CFGS,
+};
+
+static struct proto *tcpv6_prot_saved __read_mostly;
+static DEFINE_SPINLOCK(tcpv6_prot_lock);
+static struct proto tcp_bpf_prots[TCP_BPF_NUM_PROTS][TCP_BPF_NUM_CFGS];
+
+static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS],
+				   struct proto *base)
+{
+	prot[TCP_BPF_BASE]			= *base;
+	prot[TCP_BPF_BASE].unhash		= tcp_bpf_unhash;
+	prot[TCP_BPF_BASE].close		= tcp_bpf_close;
+	prot[TCP_BPF_BASE].recvmsg		= tcp_bpf_recvmsg;
+	prot[TCP_BPF_BASE].stream_memory_read	= tcp_bpf_stream_read;
+
+	prot[TCP_BPF_TX]			= prot[TCP_BPF_BASE];
+	prot[TCP_BPF_TX].sendmsg		= tcp_bpf_sendmsg;
+	prot[TCP_BPF_TX].sendpage		= tcp_bpf_sendpage;
+}
+
+static void tcp_bpf_check_v6_needs_rebuild(struct sock *sk, struct proto *ops)
+{
+	if (sk->sk_family == AF_INET6 &&
+	    unlikely(ops != smp_load_acquire(&tcpv6_prot_saved))) {
+		spin_lock_bh(&tcpv6_prot_lock);
+		if (likely(ops != tcpv6_prot_saved)) {
+			tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV6], ops);
+			smp_store_release(&tcpv6_prot_saved, ops);
+		}
+		spin_unlock_bh(&tcpv6_prot_lock);
+	}
+}
+
+static int __init tcp_bpf_v4_build_proto(void)
+{
+	tcp_bpf_rebuild_protos(tcp_bpf_prots[TCP_BPF_IPV4], &tcp_prot);
+	return 0;
+}
+core_initcall(tcp_bpf_v4_build_proto);
+
+static void tcp_bpf_update_sk_prot(struct sock *sk, struct sk_psock *psock)
+{
+	int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4;
+	int config = psock->progs.msg_parser   ? TCP_BPF_TX   : TCP_BPF_BASE;
+
+	sk_psock_update_proto(sk, psock, &tcp_bpf_prots[family][config]);
+}
+
+static void tcp_bpf_reinit_sk_prot(struct sock *sk, struct sk_psock *psock)
+{
+	int family = sk->sk_family == AF_INET6 ? TCP_BPF_IPV6 : TCP_BPF_IPV4;
+	int config = psock->progs.msg_parser   ? TCP_BPF_TX   : TCP_BPF_BASE;
+
+	/* Reinit occurs when program types change e.g. TCP_BPF_TX is removed
+	 * or added requiring sk_prot hook updates. We keep original saved
+	 * hooks in this case.
+	 */
+	sk->sk_prot = &tcp_bpf_prots[family][config];
+}
+
+static int tcp_bpf_assert_proto_ops(struct proto *ops)
+{
+	/* In order to avoid retpoline, we make assumptions when we call
+	 * into ops if e.g. a psock is not present. Make sure they are
+	 * indeed valid assumptions.
+	 */
+	return ops->recvmsg  == tcp_recvmsg &&
+	       ops->sendmsg  == tcp_sendmsg &&
+	       ops->sendpage == tcp_sendpage ? 0 : -ENOTSUPP;
+}
+
+void tcp_bpf_reinit(struct sock *sk)
+{
+	struct sk_psock *psock;
+
+	sock_owned_by_me(sk);
+
+	rcu_read_lock();
+	psock = sk_psock(sk);
+	tcp_bpf_reinit_sk_prot(sk, psock);
+	rcu_read_unlock();
+}
+
+int tcp_bpf_init(struct sock *sk)
+{
+	struct proto *ops = READ_ONCE(sk->sk_prot);
+	struct sk_psock *psock;
+
+	sock_owned_by_me(sk);
+
+	rcu_read_lock();
+	psock = sk_psock(sk);
+	if (unlikely(!psock || psock->sk_proto ||
+		     tcp_bpf_assert_proto_ops(ops))) {
+		rcu_read_unlock();
+		return -EINVAL;
+	}
+	tcp_bpf_check_v6_needs_rebuild(sk, ops);
+	tcp_bpf_update_sk_prot(sk, psock);
+	rcu_read_unlock();
+	return 0;
+}