1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */
4 #include <linux/skmsg.h>
5 #include <linux/skbuff.h>
6 #include <linux/scatterlist.h>
11 static bool sk_msg_try_coalesce_ok(struct sk_msg *msg, int elem_first_coalesce)
13 if (msg->sg.end > msg->sg.start &&
14 elem_first_coalesce < msg->sg.end)
17 if (msg->sg.end < msg->sg.start &&
18 (elem_first_coalesce > msg->sg.start ||
19 elem_first_coalesce < msg->sg.end))
25 int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len,
26 int elem_first_coalesce)
28 struct page_frag *pfrag = sk_page_frag(sk);
33 struct scatterlist *sge;
37 if (!sk_page_frag_refill(sk, pfrag))
40 orig_offset = pfrag->offset;
41 use = min_t(int, len, pfrag->size - orig_offset);
42 if (!sk_wmem_schedule(sk, use))
46 sk_msg_iter_var_prev(i);
47 sge = &msg->sg.data[i];
49 if (sk_msg_try_coalesce_ok(msg, elem_first_coalesce) &&
50 sg_page(sge) == pfrag->page &&
51 sge->offset + sge->length == orig_offset) {
54 if (sk_msg_full(msg)) {
59 sge = &msg->sg.data[msg->sg.end];
61 sg_set_page(sge, pfrag->page, use, orig_offset);
62 get_page(pfrag->page);
63 sk_msg_iter_next(msg, end);
66 sk_mem_charge(sk, use);
74 EXPORT_SYMBOL_GPL(sk_msg_alloc);
76 int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src,
79 int i = src->sg.start;
80 struct scatterlist *sge = sk_msg_elem(src, i);
81 struct scatterlist *sgd = NULL;
85 if (sge->length > off)
88 sk_msg_iter_var_next(i);
89 if (i == src->sg.end && off)
91 sge = sk_msg_elem(src, i);
95 sge_len = sge->length - off;
100 sgd = sk_msg_elem(dst, dst->sg.end - 1);
103 (sg_page(sge) == sg_page(sgd)) &&
104 (sg_virt(sge) + off == sg_virt(sgd) + sgd->length)) {
105 sgd->length += sge_len;
106 dst->sg.size += sge_len;
107 } else if (!sk_msg_full(dst)) {
108 sge_off = sge->offset + off;
109 sk_msg_page_add(dst, sg_page(sge), sge_len, sge_off);
116 sk_mem_charge(sk, sge_len);
117 sk_msg_iter_var_next(i);
118 if (i == src->sg.end && len)
120 sge = sk_msg_elem(src, i);
125 EXPORT_SYMBOL_GPL(sk_msg_clone);
127 void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes)
129 int i = msg->sg.start;
132 struct scatterlist *sge = sk_msg_elem(msg, i);
134 if (bytes < sge->length) {
135 sge->length -= bytes;
136 sge->offset += bytes;
137 sk_mem_uncharge(sk, bytes);
141 sk_mem_uncharge(sk, sge->length);
142 bytes -= sge->length;
145 sk_msg_iter_var_next(i);
146 } while (bytes && i != msg->sg.end);
149 EXPORT_SYMBOL_GPL(sk_msg_return_zero);
151 void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes)
153 int i = msg->sg.start;
156 struct scatterlist *sge = &msg->sg.data[i];
157 int uncharge = (bytes < sge->length) ? bytes : sge->length;
159 sk_mem_uncharge(sk, uncharge);
161 sk_msg_iter_var_next(i);
162 } while (i != msg->sg.end);
164 EXPORT_SYMBOL_GPL(sk_msg_return);
166 static int sk_msg_free_elem(struct sock *sk, struct sk_msg *msg, u32 i,
169 struct scatterlist *sge = sk_msg_elem(msg, i);
170 u32 len = sge->length;
173 sk_mem_uncharge(sk, len);
175 put_page(sg_page(sge));
176 memset(sge, 0, sizeof(*sge));
180 static int __sk_msg_free(struct sock *sk, struct sk_msg *msg, u32 i,
183 struct scatterlist *sge = sk_msg_elem(msg, i);
186 while (msg->sg.size) {
187 msg->sg.size -= sge->length;
188 freed += sk_msg_free_elem(sk, msg, i, charge);
189 sk_msg_iter_var_next(i);
190 sk_msg_check_to_free(msg, i, msg->sg.size);
191 sge = sk_msg_elem(msg, i);
194 consume_skb(msg->skb);
199 int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg)
201 return __sk_msg_free(sk, msg, msg->sg.start, false);
203 EXPORT_SYMBOL_GPL(sk_msg_free_nocharge);
205 int sk_msg_free(struct sock *sk, struct sk_msg *msg)
207 return __sk_msg_free(sk, msg, msg->sg.start, true);
209 EXPORT_SYMBOL_GPL(sk_msg_free);
211 static void __sk_msg_free_partial(struct sock *sk, struct sk_msg *msg,
212 u32 bytes, bool charge)
214 struct scatterlist *sge;
215 u32 i = msg->sg.start;
218 sge = sk_msg_elem(msg, i);
221 if (bytes < sge->length) {
223 sk_mem_uncharge(sk, bytes);
224 sge->length -= bytes;
225 sge->offset += bytes;
226 msg->sg.size -= bytes;
230 msg->sg.size -= sge->length;
231 bytes -= sge->length;
232 sk_msg_free_elem(sk, msg, i, charge);
233 sk_msg_iter_var_next(i);
234 sk_msg_check_to_free(msg, i, bytes);
239 void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes)
241 __sk_msg_free_partial(sk, msg, bytes, true);
243 EXPORT_SYMBOL_GPL(sk_msg_free_partial);
245 void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg,
248 __sk_msg_free_partial(sk, msg, bytes, false);
251 void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len)
253 int trim = msg->sg.size - len;
261 sk_msg_iter_var_prev(i);
263 while (msg->sg.data[i].length &&
264 trim >= msg->sg.data[i].length) {
265 trim -= msg->sg.data[i].length;
266 sk_msg_free_elem(sk, msg, i, true);
267 sk_msg_iter_var_prev(i);
272 msg->sg.data[i].length -= trim;
273 sk_mem_uncharge(sk, trim);
274 /* Adjust copybreak if it falls into the trimmed part of last buf */
275 if (msg->sg.curr == i && msg->sg.copybreak > msg->sg.data[i].length)
276 msg->sg.copybreak = msg->sg.data[i].length;
278 sk_msg_iter_var_next(i);
281 /* If we trim data a full sg elem before curr pointer update
282 * copybreak and current so that any future copy operations
283 * start at new copy location.
284 * However trimed data that has not yet been used in a copy op
285 * does not require an update.
288 msg->sg.curr = msg->sg.start;
289 msg->sg.copybreak = 0;
290 } else if (sk_msg_iter_dist(msg->sg.start, msg->sg.curr) >=
291 sk_msg_iter_dist(msg->sg.start, msg->sg.end)) {
292 sk_msg_iter_var_prev(i);
294 msg->sg.copybreak = msg->sg.data[i].length;
297 EXPORT_SYMBOL_GPL(sk_msg_trim);
299 int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
300 struct sk_msg *msg, u32 bytes)
302 int i, maxpages, ret = 0, num_elems = sk_msg_elem_used(msg);
303 const int to_max_pages = MAX_MSG_FRAGS;
304 struct page *pages[MAX_MSG_FRAGS];
305 ssize_t orig, copied, use, offset;
310 maxpages = to_max_pages - num_elems;
316 copied = iov_iter_get_pages(from, pages, bytes, maxpages,
323 iov_iter_advance(from, copied);
325 msg->sg.size += copied;
328 use = min_t(int, copied, PAGE_SIZE - offset);
329 sg_set_page(&msg->sg.data[msg->sg.end],
330 pages[i], use, offset);
331 sg_unmark_end(&msg->sg.data[msg->sg.end]);
332 sk_mem_charge(sk, use);
336 sk_msg_iter_next(msg, end);
340 /* When zerocopy is mixed with sk_msg_*copy* operations we
341 * may have a copybreak set in this case clear and prefer
342 * zerocopy remainder when possible.
344 msg->sg.copybreak = 0;
345 msg->sg.curr = msg->sg.end;
348 /* Revert iov_iter updates, msg will need to use 'trim' later if it
349 * also needs to be cleared.
352 iov_iter_revert(from, msg->sg.size - orig);
355 EXPORT_SYMBOL_GPL(sk_msg_zerocopy_from_iter);
357 int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
358 struct sk_msg *msg, u32 bytes)
360 int ret = -ENOSPC, i = msg->sg.curr;
361 struct scatterlist *sge;
366 sge = sk_msg_elem(msg, i);
367 /* This is possible if a trim operation shrunk the buffer */
368 if (msg->sg.copybreak >= sge->length) {
369 msg->sg.copybreak = 0;
370 sk_msg_iter_var_next(i);
371 if (i == msg->sg.end)
373 sge = sk_msg_elem(msg, i);
376 buf_size = sge->length - msg->sg.copybreak;
377 copy = (buf_size > bytes) ? bytes : buf_size;
378 to = sg_virt(sge) + msg->sg.copybreak;
379 msg->sg.copybreak += copy;
380 if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY)
381 ret = copy_from_iter_nocache(to, copy, from);
383 ret = copy_from_iter(to, copy, from);
391 msg->sg.copybreak = 0;
392 sk_msg_iter_var_next(i);
393 } while (i != msg->sg.end);
398 EXPORT_SYMBOL_GPL(sk_msg_memcopy_from_iter);
400 static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
402 struct sock *sk = psock->sk;
403 int copied = 0, num_sge;
406 msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC);
409 if (!sk_rmem_schedule(sk, skb, skb->len)) {
415 num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len);
416 if (unlikely(num_sge < 0)) {
421 sk_mem_charge(sk, skb->len);
424 msg->sg.size = copied;
425 msg->sg.end = num_sge == MAX_MSG_FRAGS ? 0 : num_sge;
428 sk_psock_queue_msg(psock, msg);
429 sk_psock_data_ready(sk, psock);
433 static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb,
434 u32 off, u32 len, bool ingress)
437 return sk_psock_skb_ingress(psock, skb);
439 return skb_send_sock_locked(psock->sk, skb, off, len);
442 static void sk_psock_backlog(struct work_struct *work)
444 struct sk_psock *psock = container_of(work, struct sk_psock, work);
445 struct sk_psock_work_state *state = &psock->work_state;
451 /* Lock sock to avoid losing sk_socket during loop. */
452 lock_sock(psock->sk);
461 while ((skb = skb_dequeue(&psock->ingress_skb))) {
465 ingress = tcp_skb_bpf_ingress(skb);
468 if (likely(psock->sk->sk_socket))
469 ret = sk_psock_handle_skb(psock, skb, off,
472 if (ret == -EAGAIN) {
478 /* Hard errors break pipe and stop xmit. */
479 sk_psock_report_error(psock, ret ? -ret : EPIPE);
480 sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
492 release_sock(psock->sk);
495 struct sk_psock *sk_psock_init(struct sock *sk, int node)
497 struct sk_psock *psock = kzalloc_node(sizeof(*psock),
498 GFP_ATOMIC | __GFP_NOWARN,
504 psock->eval = __SK_NONE;
506 INIT_LIST_HEAD(&psock->link);
507 spin_lock_init(&psock->link_lock);
509 INIT_WORK(&psock->work, sk_psock_backlog);
510 INIT_LIST_HEAD(&psock->ingress_msg);
511 skb_queue_head_init(&psock->ingress_skb);
513 sk_psock_set_state(psock, SK_PSOCK_TX_ENABLED);
514 refcount_set(&psock->refcnt, 1);
516 rcu_assign_sk_user_data(sk, psock);
521 EXPORT_SYMBOL_GPL(sk_psock_init);
523 struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock)
525 struct sk_psock_link *link;
527 spin_lock_bh(&psock->link_lock);
528 link = list_first_entry_or_null(&psock->link, struct sk_psock_link,
531 list_del(&link->list);
532 spin_unlock_bh(&psock->link_lock);
536 void __sk_psock_purge_ingress_msg(struct sk_psock *psock)
538 struct sk_msg *msg, *tmp;
540 list_for_each_entry_safe(msg, tmp, &psock->ingress_msg, list) {
541 list_del(&msg->list);
542 sk_msg_free(psock->sk, msg);
547 static void sk_psock_zap_ingress(struct sk_psock *psock)
549 __skb_queue_purge(&psock->ingress_skb);
550 __sk_psock_purge_ingress_msg(psock);
553 static void sk_psock_link_destroy(struct sk_psock *psock)
555 struct sk_psock_link *link, *tmp;
557 list_for_each_entry_safe(link, tmp, &psock->link, list) {
558 list_del(&link->list);
559 sk_psock_free_link(link);
563 static void sk_psock_destroy_deferred(struct work_struct *gc)
565 struct sk_psock *psock = container_of(gc, struct sk_psock, gc);
567 /* No sk_callback_lock since already detached. */
569 /* Parser has been stopped */
570 if (psock->progs.skb_parser)
571 strp_done(&psock->parser.strp);
573 cancel_work_sync(&psock->work);
575 psock_progs_drop(&psock->progs);
577 sk_psock_link_destroy(psock);
578 sk_psock_cork_free(psock);
579 sk_psock_zap_ingress(psock);
582 sock_put(psock->sk_redir);
587 void sk_psock_destroy(struct rcu_head *rcu)
589 struct sk_psock *psock = container_of(rcu, struct sk_psock, rcu);
591 INIT_WORK(&psock->gc, sk_psock_destroy_deferred);
592 schedule_work(&psock->gc);
594 EXPORT_SYMBOL_GPL(sk_psock_destroy);
596 void sk_psock_drop(struct sock *sk, struct sk_psock *psock)
598 sk_psock_cork_free(psock);
599 sk_psock_zap_ingress(psock);
601 write_lock_bh(&sk->sk_callback_lock);
602 sk_psock_restore_proto(sk, psock);
603 rcu_assign_sk_user_data(sk, NULL);
604 if (psock->progs.skb_parser)
605 sk_psock_stop_strp(sk, psock);
606 write_unlock_bh(&sk->sk_callback_lock);
607 sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED);
609 call_rcu(&psock->rcu, sk_psock_destroy);
611 EXPORT_SYMBOL_GPL(sk_psock_drop);
613 static int sk_psock_map_verd(int verdict, bool redir)
617 return redir ? __SK_REDIRECT : __SK_PASS;
626 int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
629 struct bpf_prog *prog;
634 prog = READ_ONCE(psock->progs.msg_parser);
635 if (unlikely(!prog)) {
640 sk_msg_compute_data_pointers(msg);
642 ret = BPF_PROG_RUN(prog, msg);
643 ret = sk_psock_map_verd(ret, msg->sk_redir);
644 psock->apply_bytes = msg->apply_bytes;
645 if (ret == __SK_REDIRECT) {
647 sock_put(psock->sk_redir);
648 psock->sk_redir = msg->sk_redir;
649 if (!psock->sk_redir) {
653 sock_hold(psock->sk_redir);
660 EXPORT_SYMBOL_GPL(sk_psock_msg_verdict);
662 static int sk_psock_bpf_run(struct sk_psock *psock, struct bpf_prog *prog,
668 bpf_compute_data_end_sk_skb(skb);
670 ret = BPF_PROG_RUN(prog, skb);
672 /* strparser clones the skb before handing it to a upper layer,
673 * meaning skb_orphan has been called. We NULL sk on the way out
674 * to ensure we don't trigger a BUG_ON() in skb/sk operations
675 * later and because we are not charging the memory of this skb
682 static struct sk_psock *sk_psock_from_strp(struct strparser *strp)
684 struct sk_psock_parser *parser;
686 parser = container_of(strp, struct sk_psock_parser, strp);
687 return container_of(parser, struct sk_psock, parser);
690 static void sk_psock_verdict_apply(struct sk_psock *psock,
691 struct sk_buff *skb, int verdict)
693 struct sk_psock *psock_other;
694 struct sock *sk_other;
699 sk_other = psock->sk;
700 if (sock_flag(sk_other, SOCK_DEAD) ||
701 !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) {
704 if (atomic_read(&sk_other->sk_rmem_alloc) <=
705 sk_other->sk_rcvbuf) {
706 struct tcp_skb_cb *tcp = TCP_SKB_CB(skb);
708 tcp->bpf.flags |= BPF_F_INGRESS;
709 skb_queue_tail(&psock->ingress_skb, skb);
710 schedule_work(&psock->work);
715 sk_other = tcp_skb_bpf_redirect_fetch(skb);
716 if (unlikely(!sk_other))
718 psock_other = sk_psock(sk_other);
719 if (!psock_other || sock_flag(sk_other, SOCK_DEAD) ||
720 !sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED))
722 ingress = tcp_skb_bpf_ingress(skb);
723 if ((!ingress && sock_writeable(sk_other)) ||
725 atomic_read(&sk_other->sk_rmem_alloc) <=
726 sk_other->sk_rcvbuf)) {
728 skb_set_owner_w(skb, sk_other);
729 skb_queue_tail(&psock_other->ingress_skb, skb);
730 schedule_work(&psock_other->work);
742 static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb)
744 struct sk_psock *psock = sk_psock_from_strp(strp);
745 struct bpf_prog *prog;
749 prog = READ_ONCE(psock->progs.skb_verdict);
752 tcp_skb_bpf_redirect_clear(skb);
753 ret = sk_psock_bpf_run(psock, prog, skb);
754 ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb));
757 sk_psock_verdict_apply(psock, skb, ret);
760 static int sk_psock_strp_read_done(struct strparser *strp, int err)
765 static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb)
767 struct sk_psock *psock = sk_psock_from_strp(strp);
768 struct bpf_prog *prog;
772 prog = READ_ONCE(psock->progs.skb_parser);
774 ret = sk_psock_bpf_run(psock, prog, skb);
779 /* Called with socket lock held. */
780 static void sk_psock_strp_data_ready(struct sock *sk)
782 struct sk_psock *psock;
785 psock = sk_psock(sk);
787 write_lock_bh(&sk->sk_callback_lock);
788 strp_data_ready(&psock->parser.strp);
789 write_unlock_bh(&sk->sk_callback_lock);
794 static void sk_psock_write_space(struct sock *sk)
796 struct sk_psock *psock;
797 void (*write_space)(struct sock *sk);
800 psock = sk_psock(sk);
801 if (likely(psock && sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)))
802 schedule_work(&psock->work);
803 write_space = psock->saved_write_space;
808 int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
810 static const struct strp_callbacks cb = {
811 .rcv_msg = sk_psock_strp_read,
812 .read_sock_done = sk_psock_strp_read_done,
813 .parse_msg = sk_psock_strp_parse,
816 psock->parser.enabled = false;
817 return strp_init(&psock->parser.strp, sk, &cb);
820 void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
822 struct sk_psock_parser *parser = &psock->parser;
827 parser->saved_data_ready = sk->sk_data_ready;
828 sk->sk_data_ready = sk_psock_strp_data_ready;
829 sk->sk_write_space = sk_psock_write_space;
830 parser->enabled = true;
833 void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
835 struct sk_psock_parser *parser = &psock->parser;
837 if (!parser->enabled)
840 sk->sk_data_ready = parser->saved_data_ready;
841 parser->saved_data_ready = NULL;
842 strp_stop(&parser->strp);
843 parser->enabled = false;