diff options
Diffstat (limited to 'net/core/skmsg.c')
| -rw-r--r-- | net/core/skmsg.c | 1080 |
1 files changed, 1080 insertions, 0 deletions
diff --git a/net/core/skmsg.c b/net/core/skmsg.c new file mode 100644 index 000000000..bb4fbc60b --- /dev/null +++ b/net/core/skmsg.c @@ -0,0 +1,1080 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2017 - 2018 Covalent IO, Inc. http://covalent.io */ + +#include <linux/skmsg.h> +#include <linux/skbuff.h> +#include <linux/scatterlist.h> + +#include <net/sock.h> +#include <net/tcp.h> +#include <net/tls.h> + +static bool sk_msg_try_coalesce_ok(struct sk_msg *msg, int elem_first_coalesce) +{ + if (msg->sg.end > msg->sg.start && + elem_first_coalesce < msg->sg.end) + return true; + + if (msg->sg.end < msg->sg.start && + (elem_first_coalesce > msg->sg.start || + elem_first_coalesce < msg->sg.end)) + return true; + + return false; +} + +int sk_msg_alloc(struct sock *sk, struct sk_msg *msg, int len, + int elem_first_coalesce) +{ + struct page_frag *pfrag = sk_page_frag(sk); + u32 osize = msg->sg.size; + int ret = 0; + + len -= msg->sg.size; + while (len > 0) { + struct scatterlist *sge; + u32 orig_offset; + int use, i; + + if (!sk_page_frag_refill(sk, pfrag)) { + ret = -ENOMEM; + goto msg_trim; + } + + orig_offset = pfrag->offset; + use = min_t(int, len, pfrag->size - orig_offset); + if (!sk_wmem_schedule(sk, use)) { + ret = -ENOMEM; + goto msg_trim; + } + + i = msg->sg.end; + sk_msg_iter_var_prev(i); + sge = &msg->sg.data[i]; + + if (sk_msg_try_coalesce_ok(msg, elem_first_coalesce) && + sg_page(sge) == pfrag->page && + sge->offset + sge->length == orig_offset) { + sge->length += use; + } else { + if (sk_msg_full(msg)) { + ret = -ENOSPC; + break; + } + + sge = &msg->sg.data[msg->sg.end]; + sg_unmark_end(sge); + sg_set_page(sge, pfrag->page, use, orig_offset); + get_page(pfrag->page); + sk_msg_iter_next(msg, end); + } + + sk_mem_charge(sk, use); + msg->sg.size += use; + pfrag->offset += use; + len -= use; + } + + return ret; + +msg_trim: + sk_msg_trim(sk, msg, osize); + return ret; +} +EXPORT_SYMBOL_GPL(sk_msg_alloc); + +int sk_msg_clone(struct sock *sk, struct sk_msg *dst, struct sk_msg *src, + u32 off, u32 len) +{ + int i = src->sg.start; + struct scatterlist *sge = sk_msg_elem(src, i); + struct scatterlist *sgd = NULL; + u32 sge_len, sge_off; + + while (off) { + if (sge->length > off) + break; + off -= sge->length; + sk_msg_iter_var_next(i); + if (i == src->sg.end && off) + return -ENOSPC; + sge = sk_msg_elem(src, i); + } + + while (len) { + sge_len = sge->length - off; + if (sge_len > len) + sge_len = len; + + if (dst->sg.end) + sgd = sk_msg_elem(dst, dst->sg.end - 1); + + if (sgd && + (sg_page(sge) == sg_page(sgd)) && + (sg_virt(sge) + off == sg_virt(sgd) + sgd->length)) { + sgd->length += sge_len; + dst->sg.size += sge_len; + } else if (!sk_msg_full(dst)) { + sge_off = sge->offset + off; + sk_msg_page_add(dst, sg_page(sge), sge_len, sge_off); + } else { + return -ENOSPC; + } + + off = 0; + len -= sge_len; + sk_mem_charge(sk, sge_len); + sk_msg_iter_var_next(i); + if (i == src->sg.end && len) + return -ENOSPC; + sge = sk_msg_elem(src, i); + } + + return 0; +} +EXPORT_SYMBOL_GPL(sk_msg_clone); + +void sk_msg_return_zero(struct sock *sk, struct sk_msg *msg, int bytes) +{ + int i = msg->sg.start; + + do { + struct scatterlist *sge = sk_msg_elem(msg, i); + + if (bytes < sge->length) { + sge->length -= bytes; + sge->offset += bytes; + sk_mem_uncharge(sk, bytes); + break; + } + + sk_mem_uncharge(sk, sge->length); + bytes -= sge->length; + sge->length = 0; + sge->offset = 0; + sk_msg_iter_var_next(i); + } while (bytes && i != msg->sg.end); + msg->sg.start = i; +} +EXPORT_SYMBOL_GPL(sk_msg_return_zero); + +void sk_msg_return(struct sock *sk, struct sk_msg *msg, int bytes) +{ + int i = msg->sg.start; + + do { + struct scatterlist *sge = &msg->sg.data[i]; + int uncharge = (bytes < sge->length) ? bytes : sge->length; + + sk_mem_uncharge(sk, uncharge); + bytes -= uncharge; + sk_msg_iter_var_next(i); + } while (i != msg->sg.end); +} +EXPORT_SYMBOL_GPL(sk_msg_return); + +static int sk_msg_free_elem(struct sock *sk, struct sk_msg *msg, u32 i, + bool charge) +{ + struct scatterlist *sge = sk_msg_elem(msg, i); + u32 len = sge->length; + + /* When the skb owns the memory we free it from consume_skb path. */ + if (!msg->skb) { + if (charge) + sk_mem_uncharge(sk, len); + put_page(sg_page(sge)); + } + memset(sge, 0, sizeof(*sge)); + return len; +} + +static int __sk_msg_free(struct sock *sk, struct sk_msg *msg, u32 i, + bool charge) +{ + struct scatterlist *sge = sk_msg_elem(msg, i); + int freed = 0; + + while (msg->sg.size) { + msg->sg.size -= sge->length; + freed += sk_msg_free_elem(sk, msg, i, charge); + sk_msg_iter_var_next(i); + sk_msg_check_to_free(msg, i, msg->sg.size); + sge = sk_msg_elem(msg, i); + } + consume_skb(msg->skb); + sk_msg_init(msg); + return freed; +} + +int sk_msg_free_nocharge(struct sock *sk, struct sk_msg *msg) +{ + return __sk_msg_free(sk, msg, msg->sg.start, false); +} +EXPORT_SYMBOL_GPL(sk_msg_free_nocharge); + +int sk_msg_free(struct sock *sk, struct sk_msg *msg) +{ + return __sk_msg_free(sk, msg, msg->sg.start, true); +} +EXPORT_SYMBOL_GPL(sk_msg_free); + +static void __sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, + u32 bytes, bool charge) +{ + struct scatterlist *sge; + u32 i = msg->sg.start; + + while (bytes) { + sge = sk_msg_elem(msg, i); + if (!sge->length) + break; + if (bytes < sge->length) { + if (charge) + sk_mem_uncharge(sk, bytes); + sge->length -= bytes; + sge->offset += bytes; + msg->sg.size -= bytes; + break; + } + + msg->sg.size -= sge->length; + bytes -= sge->length; + sk_msg_free_elem(sk, msg, i, charge); + sk_msg_iter_var_next(i); + sk_msg_check_to_free(msg, i, bytes); + } + msg->sg.start = i; +} + +void sk_msg_free_partial(struct sock *sk, struct sk_msg *msg, u32 bytes) +{ + __sk_msg_free_partial(sk, msg, bytes, true); +} +EXPORT_SYMBOL_GPL(sk_msg_free_partial); + +void sk_msg_free_partial_nocharge(struct sock *sk, struct sk_msg *msg, + u32 bytes) +{ + __sk_msg_free_partial(sk, msg, bytes, false); +} + +void sk_msg_trim(struct sock *sk, struct sk_msg *msg, int len) +{ + int trim = msg->sg.size - len; + u32 i = msg->sg.end; + + if (trim <= 0) { + WARN_ON(trim < 0); + return; + } + + sk_msg_iter_var_prev(i); + msg->sg.size = len; + while (msg->sg.data[i].length && + trim >= msg->sg.data[i].length) { + trim -= msg->sg.data[i].length; + sk_msg_free_elem(sk, msg, i, true); + sk_msg_iter_var_prev(i); + if (!trim) + goto out; + } + + msg->sg.data[i].length -= trim; + sk_mem_uncharge(sk, trim); + /* Adjust copybreak if it falls into the trimmed part of last buf */ + if (msg->sg.curr == i && msg->sg.copybreak > msg->sg.data[i].length) + msg->sg.copybreak = msg->sg.data[i].length; +out: + sk_msg_iter_var_next(i); + msg->sg.end = i; + + /* If we trim data a full sg elem before curr pointer update + * copybreak and current so that any future copy operations + * start at new copy location. + * However trimed data that has not yet been used in a copy op + * does not require an update. + */ + if (!msg->sg.size) { + msg->sg.curr = msg->sg.start; + msg->sg.copybreak = 0; + } else if (sk_msg_iter_dist(msg->sg.start, msg->sg.curr) >= + sk_msg_iter_dist(msg->sg.start, msg->sg.end)) { + sk_msg_iter_var_prev(i); + msg->sg.curr = i; + msg->sg.copybreak = msg->sg.data[i].length; + } +} +EXPORT_SYMBOL_GPL(sk_msg_trim); + +int sk_msg_zerocopy_from_iter(struct sock *sk, struct iov_iter *from, + struct sk_msg *msg, u32 bytes) +{ + int i, maxpages, ret = 0, num_elems = sk_msg_elem_used(msg); + const int to_max_pages = MAX_MSG_FRAGS; + struct page *pages[MAX_MSG_FRAGS]; + ssize_t orig, copied, use, offset; + + orig = msg->sg.size; + while (bytes > 0) { + i = 0; + maxpages = to_max_pages - num_elems; + if (maxpages == 0) { + ret = -EFAULT; + goto out; + } + + copied = iov_iter_get_pages(from, pages, bytes, maxpages, + &offset); + if (copied <= 0) { + ret = -EFAULT; + goto out; + } + + iov_iter_advance(from, copied); + bytes -= copied; + msg->sg.size += copied; + + while (copied) { + use = min_t(int, copied, PAGE_SIZE - offset); + sg_set_page(&msg->sg.data[msg->sg.end], + pages[i], use, offset); + sg_unmark_end(&msg->sg.data[msg->sg.end]); + sk_mem_charge(sk, use); + + offset = 0; + copied -= use; + sk_msg_iter_next(msg, end); + num_elems++; + i++; + } + /* When zerocopy is mixed with sk_msg_*copy* operations we + * may have a copybreak set in this case clear and prefer + * zerocopy remainder when possible. + */ + msg->sg.copybreak = 0; + msg->sg.curr = msg->sg.end; + } +out: + /* Revert iov_iter updates, msg will need to use 'trim' later if it + * also needs to be cleared. + */ + if (ret) + iov_iter_revert(from, msg->sg.size - orig); + return ret; +} +EXPORT_SYMBOL_GPL(sk_msg_zerocopy_from_iter); + +int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from, + struct sk_msg *msg, u32 bytes) +{ + int ret = -ENOSPC, i = msg->sg.curr; + struct scatterlist *sge; + u32 copy, buf_size; + void *to; + + do { + sge = sk_msg_elem(msg, i); + /* This is possible if a trim operation shrunk the buffer */ + if (msg->sg.copybreak >= sge->length) { + msg->sg.copybreak = 0; + sk_msg_iter_var_next(i); + if (i == msg->sg.end) + break; + sge = sk_msg_elem(msg, i); + } + + buf_size = sge->length - msg->sg.copybreak; + copy = (buf_size > bytes) ? bytes : buf_size; + to = sg_virt(sge) + msg->sg.copybreak; + msg->sg.copybreak += copy; + if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) + ret = copy_from_iter_nocache(to, copy, from); + else + ret = copy_from_iter(to, copy, from); + if (ret != copy) { + ret = -EFAULT; + goto out; + } + bytes -= copy; + if (!bytes) + break; + msg->sg.copybreak = 0; + sk_msg_iter_var_next(i); + } while (i != msg->sg.end); +out: + msg->sg.curr = i; + return ret; +} +EXPORT_SYMBOL_GPL(sk_msg_memcopy_from_iter); + +static struct sk_msg *sk_psock_create_ingress_msg(struct sock *sk, + struct sk_buff *skb) +{ + struct sk_msg *msg; + + if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) + return NULL; + + if (!sk_rmem_schedule(sk, skb, skb->truesize)) + return NULL; + + msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC); + if (unlikely(!msg)) + return NULL; + + sk_msg_init(msg); + return msg; +} + +static int sk_psock_skb_ingress_enqueue(struct sk_buff *skb, + struct sk_psock *psock, + struct sock *sk, + struct sk_msg *msg) +{ + int num_sge, copied; + + /* skb linearize may fail with ENOMEM, but lets simply try again + * later if this happens. Under memory pressure we don't want to + * drop the skb. We need to linearize the skb so that the mapping + * in skb_to_sgvec can not error. + */ + if (skb_linearize(skb)) + return -EAGAIN; + num_sge = skb_to_sgvec(skb, msg->sg.data, 0, skb->len); + if (unlikely(num_sge < 0)) + return num_sge; + + copied = skb->len; + msg->sg.start = 0; + msg->sg.size = copied; + msg->sg.end = num_sge; + msg->skb = skb; + + sk_psock_queue_msg(psock, msg); + sk_psock_data_ready(sk, psock); + return copied; +} + +static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb); + +static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb) +{ + struct sock *sk = psock->sk; + struct sk_msg *msg; + int err; + + /* If we are receiving on the same sock skb->sk is already assigned, + * skip memory accounting and owner transition seeing it already set + * correctly. + */ + if (unlikely(skb->sk == sk)) + return sk_psock_skb_ingress_self(psock, skb); + msg = sk_psock_create_ingress_msg(sk, skb); + if (!msg) + return -EAGAIN; + + /* This will transition ownership of the data from the socket where + * the BPF program was run initiating the redirect to the socket + * we will eventually receive this data on. The data will be released + * from skb_consume found in __tcp_bpf_recvmsg() after its been copied + * into user buffers. + */ + skb_set_owner_r(skb, sk); + err = sk_psock_skb_ingress_enqueue(skb, psock, sk, msg); + if (err < 0) + kfree(msg); + return err; +} + +/* Puts an skb on the ingress queue of the socket already assigned to the + * skb. In this case we do not need to check memory limits or skb_set_owner_r + * because the skb is already accounted for here. + */ +static int sk_psock_skb_ingress_self(struct sk_psock *psock, struct sk_buff *skb) +{ + struct sk_msg *msg = kzalloc(sizeof(*msg), __GFP_NOWARN | GFP_ATOMIC); + struct sock *sk = psock->sk; + int err; + + if (unlikely(!msg)) + return -EAGAIN; + sk_msg_init(msg); + skb_set_owner_r(skb, sk); + err = sk_psock_skb_ingress_enqueue(skb, psock, sk, msg); + if (err < 0) + kfree(msg); + return err; +} + +static int sk_psock_handle_skb(struct sk_psock *psock, struct sk_buff *skb, + u32 off, u32 len, bool ingress) +{ + if (!ingress) { + if (!sock_writeable(psock->sk)) + return -EAGAIN; + return skb_send_sock_locked(psock->sk, skb, off, len); + } + return sk_psock_skb_ingress(psock, skb); +} + +static void sk_psock_backlog(struct work_struct *work) +{ + struct sk_psock *psock = container_of(work, struct sk_psock, work); + struct sk_psock_work_state *state = &psock->work_state; + struct sk_buff *skb; + bool ingress; + u32 len, off; + int ret; + + /* Lock sock to avoid losing sk_socket during loop. */ + lock_sock(psock->sk); + if (state->skb) { + skb = state->skb; + len = state->len; + off = state->off; + state->skb = NULL; + goto start; + } + + while ((skb = skb_dequeue(&psock->ingress_skb))) { + len = skb->len; + off = 0; +start: + ingress = tcp_skb_bpf_ingress(skb); + do { + ret = -EIO; + if (likely(psock->sk->sk_socket)) + ret = sk_psock_handle_skb(psock, skb, off, + len, ingress); + if (ret <= 0) { + if (ret == -EAGAIN) { + state->skb = skb; + state->len = len; + state->off = off; + goto end; + } + /* Hard errors break pipe and stop xmit. */ + sk_psock_report_error(psock, ret ? -ret : EPIPE); + sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED); + kfree_skb(skb); + goto end; + } + off += ret; + len -= ret; + } while (len); + + if (!ingress) + kfree_skb(skb); + } +end: + release_sock(psock->sk); +} + +struct sk_psock *sk_psock_init(struct sock *sk, int node) +{ + struct sk_psock *psock; + struct proto *prot; + + write_lock_bh(&sk->sk_callback_lock); + + if (inet_csk_has_ulp(sk)) { + psock = ERR_PTR(-EINVAL); + goto out; + } + + if (sk->sk_user_data) { + psock = ERR_PTR(-EBUSY); + goto out; + } + + psock = kzalloc_node(sizeof(*psock), GFP_ATOMIC | __GFP_NOWARN, node); + if (!psock) { + psock = ERR_PTR(-ENOMEM); + goto out; + } + + prot = READ_ONCE(sk->sk_prot); + psock->sk = sk; + psock->eval = __SK_NONE; + psock->sk_proto = prot; + psock->saved_unhash = prot->unhash; + psock->saved_close = prot->close; + psock->saved_write_space = sk->sk_write_space; + + INIT_LIST_HEAD(&psock->link); + spin_lock_init(&psock->link_lock); + + INIT_WORK(&psock->work, sk_psock_backlog); + INIT_LIST_HEAD(&psock->ingress_msg); + skb_queue_head_init(&psock->ingress_skb); + + sk_psock_set_state(psock, SK_PSOCK_TX_ENABLED); + refcount_set(&psock->refcnt, 1); + + __rcu_assign_sk_user_data_with_flags(sk, psock, + SK_USER_DATA_NOCOPY | + SK_USER_DATA_PSOCK); + sock_hold(sk); + +out: + write_unlock_bh(&sk->sk_callback_lock); + return psock; +} +EXPORT_SYMBOL_GPL(sk_psock_init); + +struct sk_psock_link *sk_psock_link_pop(struct sk_psock *psock) +{ + struct sk_psock_link *link; + + spin_lock_bh(&psock->link_lock); + link = list_first_entry_or_null(&psock->link, struct sk_psock_link, + list); + if (link) + list_del(&link->list); + spin_unlock_bh(&psock->link_lock); + return link; +} + +void __sk_psock_purge_ingress_msg(struct sk_psock *psock) +{ + struct sk_msg *msg, *tmp; + + list_for_each_entry_safe(msg, tmp, &psock->ingress_msg, list) { + list_del(&msg->list); + sk_msg_free(psock->sk, msg); + kfree(msg); + } +} + +static void sk_psock_zap_ingress(struct sk_psock *psock) +{ + __skb_queue_purge(&psock->ingress_skb); + __sk_psock_purge_ingress_msg(psock); +} + +static void sk_psock_link_destroy(struct sk_psock *psock) +{ + struct sk_psock_link *link, *tmp; + + list_for_each_entry_safe(link, tmp, &psock->link, list) { + list_del(&link->list); + sk_psock_free_link(link); + } +} + +static void sk_psock_destroy_deferred(struct work_struct *gc) +{ + struct sk_psock *psock = container_of(gc, struct sk_psock, gc); + + /* No sk_callback_lock since already detached. */ + + /* Parser has been stopped */ + if (psock->progs.skb_parser) + strp_done(&psock->parser.strp); + + cancel_work_sync(&psock->work); + + psock_progs_drop(&psock->progs); + + sk_psock_link_destroy(psock); + sk_psock_cork_free(psock); + sk_psock_zap_ingress(psock); + + if (psock->sk_redir) + sock_put(psock->sk_redir); + sock_put(psock->sk); + kfree(psock); +} + +static void sk_psock_destroy(struct rcu_head *rcu) +{ + struct sk_psock *psock = container_of(rcu, struct sk_psock, rcu); + + INIT_WORK(&psock->gc, sk_psock_destroy_deferred); + schedule_work(&psock->gc); +} + +void sk_psock_drop(struct sock *sk, struct sk_psock *psock) +{ + sk_psock_cork_free(psock); + sk_psock_zap_ingress(psock); + + write_lock_bh(&sk->sk_callback_lock); + sk_psock_restore_proto(sk, psock); + rcu_assign_sk_user_data(sk, NULL); + if (psock->progs.skb_parser) + sk_psock_stop_strp(sk, psock); + else if (psock->progs.skb_verdict) + sk_psock_stop_verdict(sk, psock); + write_unlock_bh(&sk->sk_callback_lock); + sk_psock_clear_state(psock, SK_PSOCK_TX_ENABLED); + + call_rcu(&psock->rcu, sk_psock_destroy); +} +EXPORT_SYMBOL_GPL(sk_psock_drop); + +static int sk_psock_map_verd(int verdict, bool redir) +{ + switch (verdict) { + case SK_PASS: + return redir ? __SK_REDIRECT : __SK_PASS; + case SK_DROP: + default: + break; + } + + return __SK_DROP; +} + +int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock, + struct sk_msg *msg) +{ + struct bpf_prog *prog; + int ret; + + rcu_read_lock(); + prog = READ_ONCE(psock->progs.msg_parser); + if (unlikely(!prog)) { + ret = __SK_PASS; + goto out; + } + + sk_msg_compute_data_pointers(msg); + msg->sk = sk; + ret = bpf_prog_run_pin_on_cpu(prog, msg); + ret = sk_psock_map_verd(ret, msg->sk_redir); + psock->apply_bytes = msg->apply_bytes; + if (ret == __SK_REDIRECT) { + if (psock->sk_redir) + sock_put(psock->sk_redir); + psock->sk_redir = msg->sk_redir; + if (!psock->sk_redir) { + ret = __SK_DROP; + goto out; + } + sock_hold(psock->sk_redir); + } +out: + rcu_read_unlock(); + return ret; +} +EXPORT_SYMBOL_GPL(sk_psock_msg_verdict); + +static int sk_psock_bpf_run(struct sk_psock *psock, struct bpf_prog *prog, + struct sk_buff *skb) +{ + bpf_compute_data_end_sk_skb(skb); + return bpf_prog_run_pin_on_cpu(prog, skb); +} + +static struct sk_psock *sk_psock_from_strp(struct strparser *strp) +{ + struct sk_psock_parser *parser; + + parser = container_of(strp, struct sk_psock_parser, strp); + return container_of(parser, struct sk_psock, parser); +} + +static void sk_psock_skb_redirect(struct sk_buff *skb) +{ + struct sk_psock *psock_other; + struct sock *sk_other; + + sk_other = tcp_skb_bpf_redirect_fetch(skb); + /* This error is a buggy BPF program, it returned a redirect + * return code, but then didn't set a redirect interface. + */ + if (unlikely(!sk_other)) { + kfree_skb(skb); + return; + } + psock_other = sk_psock(sk_other); + /* This error indicates the socket is being torn down or had another + * error that caused the pipe to break. We can't send a packet on + * a socket that is in this state so we drop the skb. + */ + if (!psock_other || sock_flag(sk_other, SOCK_DEAD) || + !sk_psock_test_state(psock_other, SK_PSOCK_TX_ENABLED)) { + kfree_skb(skb); + return; + } + + skb_queue_tail(&psock_other->ingress_skb, skb); + schedule_work(&psock_other->work); +} + +static void sk_psock_tls_verdict_apply(struct sk_buff *skb, struct sock *sk, int verdict) +{ + switch (verdict) { + case __SK_REDIRECT: + sk_psock_skb_redirect(skb); + break; + case __SK_PASS: + case __SK_DROP: + default: + break; + } +} + +int sk_psock_tls_strp_read(struct sk_psock *psock, struct sk_buff *skb) +{ + struct bpf_prog *prog; + int ret = __SK_PASS; + + rcu_read_lock(); + prog = READ_ONCE(psock->progs.skb_verdict); + if (likely(prog)) { + skb->sk = psock->sk; + tcp_skb_bpf_redirect_clear(skb); + ret = sk_psock_bpf_run(psock, prog, skb); + ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb)); + skb->sk = NULL; + } + sk_psock_tls_verdict_apply(skb, psock->sk, ret); + rcu_read_unlock(); + return ret; +} +EXPORT_SYMBOL_GPL(sk_psock_tls_strp_read); + +static void sk_psock_verdict_apply(struct sk_psock *psock, + struct sk_buff *skb, int verdict) +{ + struct tcp_skb_cb *tcp; + struct sock *sk_other; + int err = -EIO; + + switch (verdict) { + case __SK_PASS: + sk_other = psock->sk; + if (sock_flag(sk_other, SOCK_DEAD) || + !sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) { + goto out_free; + } + + tcp = TCP_SKB_CB(skb); + tcp->bpf.flags |= BPF_F_INGRESS; + + /* If the queue is empty then we can submit directly + * into the msg queue. If its not empty we have to + * queue work otherwise we may get OOO data. Otherwise, + * if sk_psock_skb_ingress errors will be handled by + * retrying later from workqueue. + */ + if (skb_queue_empty(&psock->ingress_skb)) { + err = sk_psock_skb_ingress_self(psock, skb); + } + if (err < 0) { + skb_queue_tail(&psock->ingress_skb, skb); + schedule_work(&psock->work); + } + break; + case __SK_REDIRECT: + sk_psock_skb_redirect(skb); + break; + case __SK_DROP: + default: +out_free: + kfree_skb(skb); + } +} + +static void sk_psock_strp_read(struct strparser *strp, struct sk_buff *skb) +{ + struct sk_psock *psock; + struct bpf_prog *prog; + int ret = __SK_DROP; + struct sock *sk; + + rcu_read_lock(); + sk = strp->sk; + psock = sk_psock(sk); + if (unlikely(!psock)) { + kfree_skb(skb); + goto out; + } + prog = READ_ONCE(psock->progs.skb_verdict); + if (likely(prog)) { + skb->sk = sk; + tcp_skb_bpf_redirect_clear(skb); + ret = sk_psock_bpf_run(psock, prog, skb); + ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb)); + skb->sk = NULL; + } + sk_psock_verdict_apply(psock, skb, ret); +out: + rcu_read_unlock(); +} + +static int sk_psock_strp_read_done(struct strparser *strp, int err) +{ + return err; +} + +static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb) +{ + struct sk_psock *psock = sk_psock_from_strp(strp); + struct bpf_prog *prog; + int ret = skb->len; + + rcu_read_lock(); + prog = READ_ONCE(psock->progs.skb_parser); + if (likely(prog)) { + skb->sk = psock->sk; + ret = sk_psock_bpf_run(psock, prog, skb); + skb->sk = NULL; + } + rcu_read_unlock(); + return ret; +} + +/* Called with socket lock held. */ +static void sk_psock_strp_data_ready(struct sock *sk) +{ + struct sk_psock *psock; + + rcu_read_lock(); + psock = sk_psock(sk); + if (likely(psock)) { + if (tls_sw_has_ctx_rx(sk)) { + psock->parser.saved_data_ready(sk); + } else { + write_lock_bh(&sk->sk_callback_lock); + strp_data_ready(&psock->parser.strp); + write_unlock_bh(&sk->sk_callback_lock); + } + } + rcu_read_unlock(); +} + +static int sk_psock_verdict_recv(read_descriptor_t *desc, struct sk_buff *skb, + unsigned int offset, size_t orig_len) +{ + struct sock *sk = (struct sock *)desc->arg.data; + struct sk_psock *psock; + struct bpf_prog *prog; + int ret = __SK_DROP; + int len = orig_len; + + /* clone here so sk_eat_skb() in tcp_read_sock does not drop our data */ + skb = skb_clone(skb, GFP_ATOMIC); + if (!skb) { + desc->error = -ENOMEM; + return 0; + } + + rcu_read_lock(); + psock = sk_psock(sk); + if (unlikely(!psock)) { + len = 0; + kfree_skb(skb); + goto out; + } + prog = READ_ONCE(psock->progs.skb_verdict); + if (likely(prog)) { + skb->sk = sk; + tcp_skb_bpf_redirect_clear(skb); + ret = sk_psock_bpf_run(psock, prog, skb); + ret = sk_psock_map_verd(ret, tcp_skb_bpf_redirect_fetch(skb)); + skb->sk = NULL; + } + sk_psock_verdict_apply(psock, skb, ret); +out: + rcu_read_unlock(); + return len; +} + +static void sk_psock_verdict_data_ready(struct sock *sk) +{ + struct socket *sock = sk->sk_socket; + read_descriptor_t desc; + + if (unlikely(!sock || !sock->ops || !sock->ops->read_sock)) + return; + + desc.arg.data = sk; + desc.error = 0; + desc.count = 1; + + sock->ops->read_sock(sk, &desc, sk_psock_verdict_recv); +} + +static void sk_psock_write_space(struct sock *sk) +{ + struct sk_psock *psock; + void (*write_space)(struct sock *sk) = NULL; + + rcu_read_lock(); + psock = sk_psock(sk); + if (likely(psock)) { + if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) + schedule_work(&psock->work); + write_space = psock->saved_write_space; + } + rcu_read_unlock(); + if (write_space) + write_space(sk); +} + +int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock) +{ + static const struct strp_callbacks cb = { + .rcv_msg = sk_psock_strp_read, + .read_sock_done = sk_psock_strp_read_done, + .parse_msg = sk_psock_strp_parse, + }; + + psock->parser.enabled = false; + return strp_init(&psock->parser.strp, sk, &cb); +} + +void sk_psock_start_verdict(struct sock *sk, struct sk_psock *psock) +{ + struct sk_psock_parser *parser = &psock->parser; + + if (parser->enabled) + return; + + parser->saved_data_ready = sk->sk_data_ready; + sk->sk_data_ready = sk_psock_verdict_data_ready; + sk->sk_write_space = sk_psock_write_space; + parser->enabled = true; +} + +void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock) +{ + struct sk_psock_parser *parser = &psock->parser; + + if (parser->enabled) + return; + + parser->saved_data_ready = sk->sk_data_ready; + sk->sk_data_ready = sk_psock_strp_data_ready; + sk->sk_write_space = sk_psock_write_space; + parser->enabled = true; +} + +void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock) +{ + struct sk_psock_parser *parser = &psock->parser; + + if (!parser->enabled) + return; + + sk->sk_data_ready = parser->saved_data_ready; + parser->saved_data_ready = NULL; + strp_stop(&parser->strp); + parser->enabled = false; +} + +void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock) +{ + struct sk_psock_parser *parser = &psock->parser; + + if (!parser->enabled) + return; + + sk->sk_data_ready = parser->saved_data_ready; + parser->saved_data_ready = NULL; + parser->enabled = false; +} |