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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /net/ipv4/tcp_bpf.c | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'net/ipv4/tcp_bpf.c')
-rw-r--r-- | net/ipv4/tcp_bpf.c | 700 |
1 files changed, 700 insertions, 0 deletions
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c new file mode 100644 index 0000000000..53b0d62fd2 --- /dev/null +++ b/net/ipv4/tcp_bpf.c @@ -0,0 +1,700 @@ +// 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 <linux/util_macros.h> + +#include <net/inet_common.h> +#include <net/tls.h> + +void tcp_eat_skb(struct sock *sk, struct sk_buff *skb) +{ + struct tcp_sock *tcp; + int copied; + + if (!skb || !skb->len || !sk_is_tcp(sk)) + return; + + if (skb_bpf_strparser(skb)) + return; + + tcp = tcp_sk(sk); + copied = tcp->copied_seq + skb->len; + WRITE_ONCE(tcp->copied_seq, copied); + tcp_rcv_space_adjust(sk); + __tcp_cleanup_rbuf(sk, skb->len); +} + +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) { + if (sge->length) + sk_msg_iter_var_prev(i); + break; + } + } + } while (i != msg->sg.end); + + if (!ret) { + msg->sg.start = i; + sk_psock_queue_msg(psock, tmp); + sk_psock_data_ready(sk, psock); + } 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) +{ + struct msghdr msghdr = {}; + bool apply = apply_bytes; + struct scatterlist *sge; + struct page *page; + int size, ret = 0; + u32 off; + + while (1) { + struct bio_vec bvec; + bool has_tx_ulp; + + 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: + msghdr.msg_flags = flags | MSG_SPLICE_PAGES; + has_tx_ulp = tls_sw_has_ctx_tx(sk); + if (has_tx_ulp) + msghdr.msg_flags |= MSG_SENDPAGE_NOPOLICY; + + if (size < sge->length && msg->sg.start != msg->sg.end) + msghdr.msg_flags |= MSG_MORE; + + bvec_set_page(&bvec, page, size, off); + iov_iter_bvec(&msghdr.msg_iter, ITER_SOURCE, &bvec, 1, size); + ret = tcp_sendmsg_locked(sk, &msghdr, size); + 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, bool ingress, + struct sk_msg *msg, u32 bytes, int flags) +{ + struct sk_psock *psock = sk_psock_get(sk); + int ret; + + if (unlikely(!psock)) + return -EPIPE; + + 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); + +#ifdef CONFIG_BPF_SYSCALL +static int tcp_msg_wait_data(struct sock *sk, struct sk_psock *psock, + long timeo) +{ + DEFINE_WAIT_FUNC(wait, woken_wake_function); + int ret = 0; + + if (sk->sk_shutdown & RCV_SHUTDOWN) + return 1; + + if (!timeo) + return 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_lockless(&sk->sk_receive_queue), &wait); + sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); + remove_wait_queue(sk_sleep(sk), &wait); + return ret; +} + +static bool is_next_msg_fin(struct sk_psock *psock) +{ + struct scatterlist *sge; + struct sk_msg *msg_rx; + int i; + + msg_rx = sk_psock_peek_msg(psock); + i = msg_rx->sg.start; + sge = sk_msg_elem(msg_rx, i); + if (!sge->length) { + struct sk_buff *skb = msg_rx->skb; + + if (skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) + return true; + } + return false; +} + +static int tcp_bpf_recvmsg_parser(struct sock *sk, + struct msghdr *msg, + size_t len, + int flags, + int *addr_len) +{ + struct tcp_sock *tcp = tcp_sk(sk); + int peek = flags & MSG_PEEK; + u32 seq = tcp->copied_seq; + struct sk_psock *psock; + int copied = 0; + + if (unlikely(flags & MSG_ERRQUEUE)) + return inet_recv_error(sk, msg, len, addr_len); + + if (!len) + return 0; + + psock = sk_psock_get(sk); + if (unlikely(!psock)) + return tcp_recvmsg(sk, msg, len, flags, addr_len); + + lock_sock(sk); + + /* We may have received data on the sk_receive_queue pre-accept and + * then we can not use read_skb in this context because we haven't + * assigned a sk_socket yet so have no link to the ops. The work-around + * is to check the sk_receive_queue and in these cases read skbs off + * queue again. The read_skb hook is not running at this point because + * of lock_sock so we avoid having multiple runners in read_skb. + */ + if (unlikely(!skb_queue_empty(&sk->sk_receive_queue))) { + tcp_data_ready(sk); + /* This handles the ENOMEM errors if we both receive data + * pre accept and are already under memory pressure. At least + * let user know to retry. + */ + if (unlikely(!skb_queue_empty(&sk->sk_receive_queue))) { + copied = -EAGAIN; + goto out; + } + } + +msg_bytes_ready: + copied = sk_msg_recvmsg(sk, psock, msg, len, flags); + /* The typical case for EFAULT is the socket was gracefully + * shutdown with a FIN pkt. So check here the other case is + * some error on copy_page_to_iter which would be unexpected. + * On fin return correct return code to zero. + */ + if (copied == -EFAULT) { + bool is_fin = is_next_msg_fin(psock); + + if (is_fin) { + copied = 0; + seq++; + goto out; + } + } + seq += copied; + if (!copied) { + long timeo; + int data; + + if (sock_flag(sk, SOCK_DONE)) + goto out; + + if (sk->sk_err) { + copied = sock_error(sk); + goto out; + } + + if (sk->sk_shutdown & RCV_SHUTDOWN) + goto out; + + if (sk->sk_state == TCP_CLOSE) { + copied = -ENOTCONN; + goto out; + } + + timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); + if (!timeo) { + copied = -EAGAIN; + goto out; + } + + if (signal_pending(current)) { + copied = sock_intr_errno(timeo); + goto out; + } + + data = tcp_msg_wait_data(sk, psock, timeo); + if (data < 0) { + copied = data; + goto unlock; + } + if (data && !sk_psock_queue_empty(psock)) + goto msg_bytes_ready; + copied = -EAGAIN; + } +out: + if (!peek) + WRITE_ONCE(tcp->copied_seq, seq); + tcp_rcv_space_adjust(sk); + if (copied > 0) + __tcp_cleanup_rbuf(sk, copied); + +unlock: + release_sock(sk); + sk_psock_put(sk, psock); + return copied; +} + +static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, + 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 (!len) + return 0; + + psock = sk_psock_get(sk); + if (unlikely(!psock)) + return tcp_recvmsg(sk, msg, len, flags, addr_len); + if (!skb_queue_empty(&sk->sk_receive_queue) && + sk_psock_queue_empty(psock)) { + sk_psock_put(sk, psock); + return tcp_recvmsg(sk, msg, len, flags, addr_len); + } + lock_sock(sk); +msg_bytes_ready: + copied = sk_msg_recvmsg(sk, psock, msg, len, flags); + if (!copied) { + long timeo; + int data; + + timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); + data = tcp_msg_wait_data(sk, psock, timeo); + if (data < 0) { + ret = data; + goto unlock; + } + if (data) { + if (!sk_psock_queue_empty(psock)) + goto msg_bytes_ready; + release_sock(sk); + sk_psock_put(sk, psock); + return tcp_recvmsg(sk, msg, len, flags, addr_len); + } + copied = -EAGAIN; + } + ret = copied; + +unlock: + release_sock(sk); + sk_psock_put(sk, psock); + return ret; +} + +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 = sk_msg_full(msg), redir_ingress; + struct sock *sk_redir; + u32 tosend, origsize, sent, delta = 0; + u32 eval; + int ret; + +more_data: + if (psock->eval == __SK_NONE) { + /* Track delta in msg size to add/subtract it on SK_DROP from + * returned to user copied size. This ensures user doesn't + * get a positive return code with msg_cut_data and SK_DROP + * verdict. + */ + delta = msg->sg.size; + psock->eval = sk_psock_msg_verdict(sk, psock, msg); + delta -= msg->sg.size; + } + + 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; + eval = __SK_NONE; + + 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: + redir_ingress = psock->redir_ingress; + sk_redir = psock->sk_redir; + sk_msg_apply_bytes(psock, tosend); + if (!psock->apply_bytes) { + /* Clean up before releasing the sock lock. */ + eval = psock->eval; + psock->eval = __SK_NONE; + psock->sk_redir = NULL; + } + if (psock->cork) { + cork = true; + psock->cork = NULL; + } + sk_msg_return(sk, msg, tosend); + release_sock(sk); + + origsize = msg->sg.size; + ret = tcp_bpf_sendmsg_redir(sk_redir, redir_ingress, + msg, tosend, flags); + sent = origsize - msg->sg.size; + + if (eval == __SK_REDIRECT) + sock_put(sk_redir); + + 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 + delta); + 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) { + if (eval == __SK_REDIRECT) + sk_mem_charge(sk, tosend - sent); + 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 copied = 0, err = 0; + struct sk_psock *psock; + long timeo; + int flags; + + /* Don't let internal flags through */ + flags = (msg->msg_flags & ~MSG_SENDPAGE_DECRYPTED); + flags |= MSG_NO_SHARED_FRAGS; + + 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; +} + +enum { + TCP_BPF_IPV4, + TCP_BPF_IPV6, + TCP_BPF_NUM_PROTS, +}; + +enum { + TCP_BPF_BASE, + TCP_BPF_TX, + TCP_BPF_RX, + TCP_BPF_TXRX, + 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].destroy = sock_map_destroy; + prot[TCP_BPF_BASE].close = sock_map_close; + prot[TCP_BPF_BASE].recvmsg = tcp_bpf_recvmsg; + prot[TCP_BPF_BASE].sock_is_readable = sk_msg_is_readable; + + prot[TCP_BPF_TX] = prot[TCP_BPF_BASE]; + prot[TCP_BPF_TX].sendmsg = tcp_bpf_sendmsg; + + prot[TCP_BPF_RX] = prot[TCP_BPF_BASE]; + prot[TCP_BPF_RX].recvmsg = tcp_bpf_recvmsg_parser; + + prot[TCP_BPF_TXRX] = prot[TCP_BPF_TX]; + prot[TCP_BPF_TXRX].recvmsg = tcp_bpf_recvmsg_parser; +} + +static void tcp_bpf_check_v6_needs_rebuild(struct proto *ops) +{ + if (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; +} +late_initcall(tcp_bpf_v4_build_proto); + +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 ? 0 : -ENOTSUPP; +} + +int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore) +{ + 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; + + if (psock->progs.stream_verdict || psock->progs.skb_verdict) { + config = (config == TCP_BPF_TX) ? TCP_BPF_TXRX : TCP_BPF_RX; + } + + if (restore) { + if (inet_csk_has_ulp(sk)) { + /* TLS does not have an unhash proto in SW cases, + * but we need to ensure we stop using the sock_map + * unhash routine because the associated psock is being + * removed. So use the original unhash handler. + */ + WRITE_ONCE(sk->sk_prot->unhash, psock->saved_unhash); + tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space); + } else { + sk->sk_write_space = psock->saved_write_space; + /* Pairs with lockless read in sk_clone_lock() */ + sock_replace_proto(sk, psock->sk_proto); + } + return 0; + } + + if (sk->sk_family == AF_INET6) { + if (tcp_bpf_assert_proto_ops(psock->sk_proto)) + return -EINVAL; + + tcp_bpf_check_v6_needs_rebuild(psock->sk_proto); + } + + /* Pairs with lockless read in sk_clone_lock() */ + sock_replace_proto(sk, &tcp_bpf_prots[family][config]); + return 0; +} +EXPORT_SYMBOL_GPL(tcp_bpf_update_proto); + +/* If a child got cloned from a listening socket that had tcp_bpf + * protocol callbacks installed, we need to restore the callbacks to + * the default ones because the child does not inherit the psock state + * that tcp_bpf callbacks expect. + */ +void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) +{ + struct proto *prot = newsk->sk_prot; + + if (is_insidevar(prot, tcp_bpf_prots)) + newsk->sk_prot = sk->sk_prot_creator; +} +#endif /* CONFIG_BPF_SYSCALL */ |