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net.c
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// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/net.h>
#include <linux/compat.h>
#include <net/compat.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "kbuf.h"
#include "alloc_cache.h"
#include "net.h"
#include "notif.h"
#include "rsrc.h"
#if defined(CONFIG_NET)
struct io_shutdown {
struct file *file;
int how;
};
struct io_accept {
struct file *file;
struct sockaddr __user *addr;
int __user *addr_len;
int flags;
u32 file_slot;
unsigned long nofile;
};
struct io_socket {
struct file *file;
int domain;
int type;
int protocol;
int flags;
u32 file_slot;
unsigned long nofile;
};
struct io_connect {
struct file *file;
struct sockaddr __user *addr;
int addr_len;
bool in_progress;
bool seen_econnaborted;
};
struct io_sr_msg {
struct file *file;
union {
struct compat_msghdr __user *umsg_compat;
struct user_msghdr __user *umsg;
void __user *buf;
};
int len;
unsigned done_io;
unsigned msg_flags;
unsigned nr_multishot_loops;
u16 flags;
/* initialised and used only by !msg send variants */
u16 addr_len;
u16 buf_group;
void __user *addr;
void __user *msg_control;
/* used only for send zerocopy */
struct io_kiocb *notif;
};
/*
* Number of times we'll try and do receives if there's more data. If we
* exceed this limit, then add us to the back of the queue and retry from
* there. This helps fairness between flooding clients.
*/
#define MULTISHOT_MAX_RETRY 32
int io_shutdown_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_shutdown *shutdown = io_kiocb_to_cmd(req, struct io_shutdown);
if (unlikely(sqe->off || sqe->addr || sqe->rw_flags ||
sqe->buf_index || sqe->splice_fd_in))
return -EINVAL;
shutdown->how = READ_ONCE(sqe->len);
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}
int io_shutdown(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_shutdown *shutdown = io_kiocb_to_cmd(req, struct io_shutdown);
struct socket *sock;
int ret;
WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);
sock = sock_from_file(req->file);
if (unlikely(!sock))
return -ENOTSOCK;
ret = __sys_shutdown_sock(sock, shutdown->how);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
static bool io_net_retry(struct socket *sock, int flags)
{
if (!(flags & MSG_WAITALL))
return false;
return sock->type == SOCK_STREAM || sock->type == SOCK_SEQPACKET;
}
static void io_netmsg_iovec_free(struct io_async_msghdr *kmsg)
{
if (kmsg->free_iov) {
kfree(kmsg->free_iov);
kmsg->free_iov_nr = 0;
kmsg->free_iov = NULL;
}
}
static void io_netmsg_recycle(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_async_msghdr *hdr = req->async_data;
struct iovec *iov;
/* can't recycle, ensure we free the iovec if we have one */
if (unlikely(issue_flags & IO_URING_F_UNLOCKED)) {
io_netmsg_iovec_free(hdr);
return;
}
/* Let normal cleanup path reap it if we fail adding to the cache */
iov = hdr->free_iov;
if (io_alloc_cache_put(&req->ctx->netmsg_cache, hdr)) {
if (iov)
kasan_mempool_poison_object(iov);
req->async_data = NULL;
req->flags &= ~REQ_F_ASYNC_DATA;
}
}
static struct io_async_msghdr *io_msg_alloc_async(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_async_msghdr *hdr;
hdr = io_alloc_cache_get(&ctx->netmsg_cache);
if (hdr) {
if (hdr->free_iov) {
kasan_mempool_unpoison_object(hdr->free_iov,
hdr->free_iov_nr * sizeof(struct iovec));
req->flags |= REQ_F_NEED_CLEANUP;
}
req->flags |= REQ_F_ASYNC_DATA;
req->async_data = hdr;
return hdr;
}
if (!io_alloc_async_data(req)) {
hdr = req->async_data;
hdr->free_iov_nr = 0;
hdr->free_iov = NULL;
return hdr;
}
return NULL;
}
/* assign new iovec to kmsg, if we need to */
static int io_net_vec_assign(struct io_kiocb *req, struct io_async_msghdr *kmsg,
struct iovec *iov)
{
if (iov) {
req->flags |= REQ_F_NEED_CLEANUP;
kmsg->free_iov_nr = kmsg->msg.msg_iter.nr_segs;
if (kmsg->free_iov)
kfree(kmsg->free_iov);
kmsg->free_iov = iov;
}
return 0;
}
static inline void io_mshot_prep_retry(struct io_kiocb *req,
struct io_async_msghdr *kmsg)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
req->flags &= ~REQ_F_BL_EMPTY;
sr->done_io = 0;
sr->len = 0; /* get from the provided buffer */
req->buf_index = sr->buf_group;
}
#ifdef CONFIG_COMPAT
static int io_compat_msg_copy_hdr(struct io_kiocb *req,
struct io_async_msghdr *iomsg,
struct compat_msghdr *msg, int ddir)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct compat_iovec __user *uiov;
struct iovec *iov;
int ret, nr_segs;
if (iomsg->free_iov) {
nr_segs = iomsg->free_iov_nr;
iov = iomsg->free_iov;
} else {
iov = &iomsg->fast_iov;
nr_segs = 1;
}
if (copy_from_user(msg, sr->umsg_compat, sizeof(*msg)))
return -EFAULT;
uiov = compat_ptr(msg->msg_iov);
if (req->flags & REQ_F_BUFFER_SELECT) {
compat_ssize_t clen;
if (msg->msg_iovlen == 0) {
sr->len = iov->iov_len = 0;
iov->iov_base = NULL;
} else if (msg->msg_iovlen > 1) {
return -EINVAL;
} else {
if (!access_ok(uiov, sizeof(*uiov)))
return -EFAULT;
if (__get_user(clen, &uiov->iov_len))
return -EFAULT;
if (clen < 0)
return -EINVAL;
sr->len = clen;
}
return 0;
}
ret = __import_iovec(ddir, (struct iovec __user *)uiov, msg->msg_iovlen,
nr_segs, &iov, &iomsg->msg.msg_iter, true);
if (unlikely(ret < 0))
return ret;
return io_net_vec_assign(req, iomsg, iov);
}
#endif
static int io_msg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg,
struct user_msghdr *msg, int ddir)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct iovec *iov;
int ret, nr_segs;
if (iomsg->free_iov) {
nr_segs = iomsg->free_iov_nr;
iov = iomsg->free_iov;
} else {
iov = &iomsg->fast_iov;
nr_segs = 1;
}
if (!user_access_begin(sr->umsg, sizeof(*sr->umsg)))
return -EFAULT;
ret = -EFAULT;
unsafe_get_user(msg->msg_name, &sr->umsg->msg_name, ua_end);
unsafe_get_user(msg->msg_namelen, &sr->umsg->msg_namelen, ua_end);
unsafe_get_user(msg->msg_iov, &sr->umsg->msg_iov, ua_end);
unsafe_get_user(msg->msg_iovlen, &sr->umsg->msg_iovlen, ua_end);
unsafe_get_user(msg->msg_control, &sr->umsg->msg_control, ua_end);
unsafe_get_user(msg->msg_controllen, &sr->umsg->msg_controllen, ua_end);
msg->msg_flags = 0;
if (req->flags & REQ_F_BUFFER_SELECT) {
if (msg->msg_iovlen == 0) {
sr->len = iov->iov_len = 0;
iov->iov_base = NULL;
} else if (msg->msg_iovlen > 1) {
ret = -EINVAL;
goto ua_end;
} else {
/* we only need the length for provided buffers */
if (!access_ok(&msg->msg_iov[0].iov_len, sizeof(__kernel_size_t)))
goto ua_end;
unsafe_get_user(iov->iov_len, &msg->msg_iov[0].iov_len,
ua_end);
sr->len = iov->iov_len;
}
ret = 0;
ua_end:
user_access_end();
return ret;
}
user_access_end();
ret = __import_iovec(ddir, msg->msg_iov, msg->msg_iovlen, nr_segs,
&iov, &iomsg->msg.msg_iter, false);
if (unlikely(ret < 0))
return ret;
return io_net_vec_assign(req, iomsg, iov);
}
static int io_sendmsg_copy_hdr(struct io_kiocb *req,
struct io_async_msghdr *iomsg)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct user_msghdr msg;
int ret;
iomsg->msg.msg_name = &iomsg->addr;
iomsg->msg.msg_iter.nr_segs = 0;
#ifdef CONFIG_COMPAT
if (unlikely(req->ctx->compat)) {
struct compat_msghdr cmsg;
ret = io_compat_msg_copy_hdr(req, iomsg, &cmsg, ITER_SOURCE);
if (unlikely(ret))
return ret;
return __get_compat_msghdr(&iomsg->msg, &cmsg, NULL);
}
#endif
ret = io_msg_copy_hdr(req, iomsg, &msg, ITER_SOURCE);
if (unlikely(ret))
return ret;
ret = __copy_msghdr(&iomsg->msg, &msg, NULL);
/* save msg_control as sys_sendmsg() overwrites it */
sr->msg_control = iomsg->msg.msg_control_user;
return ret;
}
void io_sendmsg_recvmsg_cleanup(struct io_kiocb *req)
{
struct io_async_msghdr *io = req->async_data;
io_netmsg_iovec_free(io);
}
static int io_send_setup(struct io_kiocb *req)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct io_async_msghdr *kmsg = req->async_data;
int ret;
kmsg->msg.msg_name = NULL;
kmsg->msg.msg_namelen = 0;
kmsg->msg.msg_control = NULL;
kmsg->msg.msg_controllen = 0;
kmsg->msg.msg_ubuf = NULL;
if (sr->addr) {
ret = move_addr_to_kernel(sr->addr, sr->addr_len, &kmsg->addr);
if (unlikely(ret < 0))
return ret;
kmsg->msg.msg_name = &kmsg->addr;
kmsg->msg.msg_namelen = sr->addr_len;
}
if (!io_do_buffer_select(req)) {
ret = import_ubuf(ITER_SOURCE, sr->buf, sr->len,
&kmsg->msg.msg_iter);
if (unlikely(ret < 0))
return ret;
}
return 0;
}
static int io_sendmsg_prep_setup(struct io_kiocb *req, int is_msg)
{
struct io_async_msghdr *kmsg;
int ret;
kmsg = io_msg_alloc_async(req);
if (unlikely(!kmsg))
return -ENOMEM;
if (!is_msg)
return io_send_setup(req);
ret = io_sendmsg_copy_hdr(req, kmsg);
if (!ret)
req->flags |= REQ_F_NEED_CLEANUP;
return ret;
}
#define SENDMSG_FLAGS (IORING_RECVSEND_POLL_FIRST | IORING_RECVSEND_BUNDLE)
int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
sr->done_io = 0;
if (req->opcode == IORING_OP_SEND) {
if (READ_ONCE(sqe->__pad3[0]))
return -EINVAL;
sr->addr = u64_to_user_ptr(READ_ONCE(sqe->addr2));
sr->addr_len = READ_ONCE(sqe->addr_len);
} else if (sqe->addr2 || sqe->file_index) {
return -EINVAL;
}
sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
sr->len = READ_ONCE(sqe->len);
sr->flags = READ_ONCE(sqe->ioprio);
if (sr->flags & ~SENDMSG_FLAGS)
return -EINVAL;
sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL;
if (sr->msg_flags & MSG_DONTWAIT)
req->flags |= REQ_F_NOWAIT;
if (sr->flags & IORING_RECVSEND_BUNDLE) {
if (req->opcode == IORING_OP_SENDMSG)
return -EINVAL;
if (!(req->flags & REQ_F_BUFFER_SELECT))
return -EINVAL;
sr->msg_flags |= MSG_WAITALL;
sr->buf_group = req->buf_index;
req->buf_list = NULL;
}
if (req->flags & REQ_F_BUFFER_SELECT && sr->len)
return -EINVAL;
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
sr->msg_flags |= MSG_CMSG_COMPAT;
#endif
return io_sendmsg_prep_setup(req, req->opcode == IORING_OP_SENDMSG);
}
static void io_req_msg_cleanup(struct io_kiocb *req,
unsigned int issue_flags)
{
req->flags &= ~REQ_F_NEED_CLEANUP;
io_netmsg_recycle(req, issue_flags);
}
/*
* For bundle completions, we need to figure out how many segments we consumed.
* A bundle could be using a single ITER_UBUF if that's all we mapped, or it
* could be using an ITER_IOVEC. If the latter, then if we consumed all of
* the segments, then it's a trivial questiont o answer. If we have residual
* data in the iter, then loop the segments to figure out how much we
* transferred.
*/
static int io_bundle_nbufs(struct io_async_msghdr *kmsg, int ret)
{
struct iovec *iov;
int nbufs;
/* no data is always zero segments, and a ubuf is always 1 segment */
if (ret <= 0)
return 0;
if (iter_is_ubuf(&kmsg->msg.msg_iter))
return 1;
iov = kmsg->free_iov;
if (!iov)
iov = &kmsg->fast_iov;
/* if all data was transferred, it's basic pointer math */
if (!iov_iter_count(&kmsg->msg.msg_iter))
return iter_iov(&kmsg->msg.msg_iter) - iov;
/* short transfer, count segments */
nbufs = 0;
do {
int this_len = min_t(int, iov[nbufs].iov_len, ret);
nbufs++;
ret -= this_len;
} while (ret);
return nbufs;
}
static inline bool io_send_finish(struct io_kiocb *req, int *ret,
struct io_async_msghdr *kmsg,
unsigned issue_flags)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
bool bundle_finished = *ret <= 0;
unsigned int cflags;
if (!(sr->flags & IORING_RECVSEND_BUNDLE)) {
cflags = io_put_kbuf(req, issue_flags);
goto finish;
}
cflags = io_put_kbufs(req, io_bundle_nbufs(kmsg, *ret), issue_flags);
if (bundle_finished || req->flags & REQ_F_BL_EMPTY)
goto finish;
/*
* Fill CQE for this receive and see if we should keep trying to
* receive from this socket.
*/
if (io_req_post_cqe(req, *ret, cflags | IORING_CQE_F_MORE)) {
io_mshot_prep_retry(req, kmsg);
return false;
}
/* Otherwise stop bundle and use the current result. */
finish:
io_req_set_res(req, *ret, cflags);
*ret = IOU_OK;
return true;
}
int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct io_async_msghdr *kmsg = req->async_data;
struct socket *sock;
unsigned flags;
int min_ret = 0;
int ret;
sock = sock_from_file(req->file);
if (unlikely(!sock))
return -ENOTSOCK;
if (!(req->flags & REQ_F_POLLED) &&
(sr->flags & IORING_RECVSEND_POLL_FIRST))
return -EAGAIN;
flags = sr->msg_flags;
if (issue_flags & IO_URING_F_NONBLOCK)
flags |= MSG_DONTWAIT;
if (flags & MSG_WAITALL)
min_ret = iov_iter_count(&kmsg->msg.msg_iter);
kmsg->msg.msg_control_user = sr->msg_control;
ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
if (ret < min_ret) {
if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
return -EAGAIN;
if (ret > 0 && io_net_retry(sock, flags)) {
kmsg->msg.msg_controllen = 0;
kmsg->msg.msg_control = NULL;
sr->done_io += ret;
req->flags |= REQ_F_BL_NO_RECYCLE;
return -EAGAIN;
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
req_set_fail(req);
}
io_req_msg_cleanup(req, issue_flags);
if (ret >= 0)
ret += sr->done_io;
else if (sr->done_io)
ret = sr->done_io;
io_req_set_res(req, ret, 0);
return IOU_OK;
}
int io_send(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct io_async_msghdr *kmsg = req->async_data;
struct socket *sock;
unsigned flags;
int min_ret = 0;
int ret;
sock = sock_from_file(req->file);
if (unlikely(!sock))
return -ENOTSOCK;
if (!(req->flags & REQ_F_POLLED) &&
(sr->flags & IORING_RECVSEND_POLL_FIRST))
return -EAGAIN;
flags = sr->msg_flags;
if (issue_flags & IO_URING_F_NONBLOCK)
flags |= MSG_DONTWAIT;
retry_bundle:
if (io_do_buffer_select(req)) {
struct buf_sel_arg arg = {
.iovs = &kmsg->fast_iov,
.max_len = INT_MAX,
.nr_iovs = 1,
.mode = KBUF_MODE_EXPAND,
};
if (kmsg->free_iov) {
arg.nr_iovs = kmsg->free_iov_nr;
arg.iovs = kmsg->free_iov;
arg.mode |= KBUF_MODE_FREE;
}
if (!(sr->flags & IORING_RECVSEND_BUNDLE))
arg.nr_iovs = 1;
ret = io_buffers_select(req, &arg, issue_flags);
if (unlikely(ret < 0))
return ret;
sr->len = arg.out_len;
iov_iter_init(&kmsg->msg.msg_iter, ITER_SOURCE, arg.iovs, ret,
arg.out_len);
if (arg.iovs != &kmsg->fast_iov && arg.iovs != kmsg->free_iov) {
kmsg->free_iov_nr = ret;
kmsg->free_iov = arg.iovs;
}
}
/*
* If MSG_WAITALL is set, or this is a bundle send, then we need
* the full amount. If just bundle is set, if we do a short send
* then we complete the bundle sequence rather than continue on.
*/
if (flags & MSG_WAITALL || sr->flags & IORING_RECVSEND_BUNDLE)
min_ret = iov_iter_count(&kmsg->msg.msg_iter);
flags &= ~MSG_INTERNAL_SENDMSG_FLAGS;
kmsg->msg.msg_flags = flags;
ret = sock_sendmsg(sock, &kmsg->msg);
if (ret < min_ret) {
if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
return -EAGAIN;
if (ret > 0 && io_net_retry(sock, flags)) {
sr->len -= ret;
sr->buf += ret;
sr->done_io += ret;
req->flags |= REQ_F_BL_NO_RECYCLE;
return -EAGAIN;
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
req_set_fail(req);
}
if (ret >= 0)
ret += sr->done_io;
else if (sr->done_io)
ret = sr->done_io;
if (!io_send_finish(req, &ret, kmsg, issue_flags))
goto retry_bundle;
io_req_msg_cleanup(req, issue_flags);
return ret;
}
static int io_recvmsg_mshot_prep(struct io_kiocb *req,
struct io_async_msghdr *iomsg,
int namelen, size_t controllen)
{
if ((req->flags & (REQ_F_APOLL_MULTISHOT|REQ_F_BUFFER_SELECT)) ==
(REQ_F_APOLL_MULTISHOT|REQ_F_BUFFER_SELECT)) {
int hdr;
if (unlikely(namelen < 0))
return -EOVERFLOW;
if (check_add_overflow(sizeof(struct io_uring_recvmsg_out),
namelen, &hdr))
return -EOVERFLOW;
if (check_add_overflow(hdr, controllen, &hdr))
return -EOVERFLOW;
iomsg->namelen = namelen;
iomsg->controllen = controllen;
return 0;
}
return 0;
}
static int io_recvmsg_copy_hdr(struct io_kiocb *req,
struct io_async_msghdr *iomsg)
{
struct user_msghdr msg;
int ret;
iomsg->msg.msg_name = &iomsg->addr;
iomsg->msg.msg_iter.nr_segs = 0;
#ifdef CONFIG_COMPAT
if (unlikely(req->ctx->compat)) {
struct compat_msghdr cmsg;
ret = io_compat_msg_copy_hdr(req, iomsg, &cmsg, ITER_DEST);
if (unlikely(ret))
return ret;
ret = __get_compat_msghdr(&iomsg->msg, &cmsg, &iomsg->uaddr);
if (unlikely(ret))
return ret;
return io_recvmsg_mshot_prep(req, iomsg, cmsg.msg_namelen,
cmsg.msg_controllen);
}
#endif
ret = io_msg_copy_hdr(req, iomsg, &msg, ITER_DEST);
if (unlikely(ret))
return ret;
ret = __copy_msghdr(&iomsg->msg, &msg, &iomsg->uaddr);
if (unlikely(ret))
return ret;
return io_recvmsg_mshot_prep(req, iomsg, msg.msg_namelen,
msg.msg_controllen);
}
static int io_recvmsg_prep_setup(struct io_kiocb *req)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct io_async_msghdr *kmsg;
int ret;
kmsg = io_msg_alloc_async(req);
if (unlikely(!kmsg))
return -ENOMEM;
if (req->opcode == IORING_OP_RECV) {
kmsg->msg.msg_name = NULL;
kmsg->msg.msg_namelen = 0;
kmsg->msg.msg_control = NULL;
kmsg->msg.msg_get_inq = 1;
kmsg->msg.msg_controllen = 0;
kmsg->msg.msg_iocb = NULL;
kmsg->msg.msg_ubuf = NULL;
if (!io_do_buffer_select(req)) {
ret = import_ubuf(ITER_DEST, sr->buf, sr->len,
&kmsg->msg.msg_iter);
if (unlikely(ret))
return ret;
}
return 0;
}
ret = io_recvmsg_copy_hdr(req, kmsg);
if (!ret)
req->flags |= REQ_F_NEED_CLEANUP;
return ret;
}
#define RECVMSG_FLAGS (IORING_RECVSEND_POLL_FIRST | IORING_RECV_MULTISHOT | \
IORING_RECVSEND_BUNDLE)
int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
sr->done_io = 0;
if (unlikely(sqe->file_index || sqe->addr2))
return -EINVAL;
sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
sr->len = READ_ONCE(sqe->len);
sr->flags = READ_ONCE(sqe->ioprio);
if (sr->flags & ~RECVMSG_FLAGS)
return -EINVAL;
sr->msg_flags = READ_ONCE(sqe->msg_flags);
if (sr->msg_flags & MSG_DONTWAIT)
req->flags |= REQ_F_NOWAIT;
if (sr->msg_flags & MSG_ERRQUEUE)
req->flags |= REQ_F_CLEAR_POLLIN;
if (req->flags & REQ_F_BUFFER_SELECT) {
/*
* Store the buffer group for this multishot receive separately,
* as if we end up doing an io-wq based issue that selects a
* buffer, it has to be committed immediately and that will
* clear ->buf_list. This means we lose the link to the buffer
* list, and the eventual buffer put on completion then cannot
* restore it.
*/
sr->buf_group = req->buf_index;
req->buf_list = NULL;
}
if (sr->flags & IORING_RECV_MULTISHOT) {
if (!(req->flags & REQ_F_BUFFER_SELECT))
return -EINVAL;
if (sr->msg_flags & MSG_WAITALL)
return -EINVAL;
if (req->opcode == IORING_OP_RECV && sr->len)
return -EINVAL;
req->flags |= REQ_F_APOLL_MULTISHOT;
}
if (sr->flags & IORING_RECVSEND_BUNDLE) {
if (req->opcode == IORING_OP_RECVMSG)
return -EINVAL;
}
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
sr->msg_flags |= MSG_CMSG_COMPAT;
#endif
sr->nr_multishot_loops = 0;
return io_recvmsg_prep_setup(req);
}
/*
* Finishes io_recv and io_recvmsg.
*
* Returns true if it is actually finished, or false if it should run
* again (for multishot).
*/
static inline bool io_recv_finish(struct io_kiocb *req, int *ret,
struct io_async_msghdr *kmsg,
bool mshot_finished, unsigned issue_flags)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
unsigned int cflags;
if (sr->flags & IORING_RECVSEND_BUNDLE)
cflags = io_put_kbufs(req, io_bundle_nbufs(kmsg, *ret),
issue_flags);
else
cflags = io_put_kbuf(req, issue_flags);
if (kmsg->msg.msg_inq > 0)
cflags |= IORING_CQE_F_SOCK_NONEMPTY;
/* bundle with no more immediate buffers, we're done */
if (sr->flags & IORING_RECVSEND_BUNDLE && req->flags & REQ_F_BL_EMPTY)
goto finish;
/*
* Fill CQE for this receive and see if we should keep trying to
* receive from this socket.
*/
if ((req->flags & REQ_F_APOLL_MULTISHOT) && !mshot_finished &&
io_req_post_cqe(req, *ret, cflags | IORING_CQE_F_MORE)) {
int mshot_retry_ret = IOU_ISSUE_SKIP_COMPLETE;
io_mshot_prep_retry(req, kmsg);
/* Known not-empty or unknown state, retry */
if (cflags & IORING_CQE_F_SOCK_NONEMPTY || kmsg->msg.msg_inq < 0) {
if (sr->nr_multishot_loops++ < MULTISHOT_MAX_RETRY)
return false;
/* mshot retries exceeded, force a requeue */
sr->nr_multishot_loops = 0;
mshot_retry_ret = IOU_REQUEUE;
}
if (issue_flags & IO_URING_F_MULTISHOT)
*ret = mshot_retry_ret;
else
*ret = -EAGAIN;
return true;
}
/* Finish the request / stop multishot. */
finish:
io_req_set_res(req, *ret, cflags);
if (issue_flags & IO_URING_F_MULTISHOT)
*ret = IOU_STOP_MULTISHOT;
else
*ret = IOU_OK;
io_req_msg_cleanup(req, issue_flags);
return true;
}
static int io_recvmsg_prep_multishot(struct io_async_msghdr *kmsg,
struct io_sr_msg *sr, void __user **buf,
size_t *len)
{
unsigned long ubuf = (unsigned long) *buf;
unsigned long hdr;
hdr = sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
kmsg->controllen;
if (*len < hdr)
return -EFAULT;
if (kmsg->controllen) {
unsigned long control = ubuf + hdr - kmsg->controllen;
kmsg->msg.msg_control_user = (void __user *) control;
kmsg->msg.msg_controllen = kmsg->controllen;
}
sr->buf = *buf; /* stash for later copy */
*buf = (void __user *) (ubuf + hdr);
kmsg->payloadlen = *len = *len - hdr;
return 0;
}
struct io_recvmsg_multishot_hdr {
struct io_uring_recvmsg_out msg;
struct sockaddr_storage addr;
};
static int io_recvmsg_multishot(struct socket *sock, struct io_sr_msg *io,
struct io_async_msghdr *kmsg,
unsigned int flags, bool *finished)
{
int err;
int copy_len;
struct io_recvmsg_multishot_hdr hdr;
if (kmsg->namelen)
kmsg->msg.msg_name = &hdr.addr;
kmsg->msg.msg_flags = flags & (MSG_CMSG_CLOEXEC|MSG_CMSG_COMPAT);
kmsg->msg.msg_namelen = 0;
if (sock->file->f_flags & O_NONBLOCK)
flags |= MSG_DONTWAIT;
err = sock_recvmsg(sock, &kmsg->msg, flags);
*finished = err <= 0;
if (err < 0)
return err;
hdr.msg = (struct io_uring_recvmsg_out) {
.controllen = kmsg->controllen - kmsg->msg.msg_controllen,
.flags = kmsg->msg.msg_flags & ~MSG_CMSG_COMPAT
};
hdr.msg.payloadlen = err;
if (err > kmsg->payloadlen)
err = kmsg->payloadlen;
copy_len = sizeof(struct io_uring_recvmsg_out);
if (kmsg->msg.msg_namelen > kmsg->namelen)
copy_len += kmsg->namelen;
else
copy_len += kmsg->msg.msg_namelen;
/*
* "fromlen shall refer to the value before truncation.."
* 1003.1g
*/
hdr.msg.namelen = kmsg->msg.msg_namelen;
/* ensure that there is no gap between hdr and sockaddr_storage */
BUILD_BUG_ON(offsetof(struct io_recvmsg_multishot_hdr, addr) !=
sizeof(struct io_uring_recvmsg_out));
if (copy_to_user(io->buf, &hdr, copy_len)) {
*finished = true;
return -EFAULT;
}
return sizeof(struct io_uring_recvmsg_out) + kmsg->namelen +
kmsg->controllen + err;
}
int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_sr_msg *sr = io_kiocb_to_cmd(req, struct io_sr_msg);
struct io_async_msghdr *kmsg = req->async_data;
struct socket *sock;
unsigned flags;
int ret, min_ret = 0;
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK;
bool mshot_finished = true;
sock = sock_from_file(req->file);
if (unlikely(!sock))
return -ENOTSOCK;
if (!(req->flags & REQ_F_POLLED) &&
(sr->flags & IORING_RECVSEND_POLL_FIRST))
return -EAGAIN;
flags = sr->msg_flags;
if (force_nonblock)
flags |= MSG_DONTWAIT;
retry_multishot:
if (io_do_buffer_select(req)) {
void __user *buf;
size_t len = sr->len;
buf = io_buffer_select(req, &len, issue_flags);
if (!buf)
return -ENOBUFS;
if (req->flags & REQ_F_APOLL_MULTISHOT) {
ret = io_recvmsg_prep_multishot(kmsg, sr, &buf, &len);
if (ret) {
io_kbuf_recycle(req, issue_flags);
return ret;
}
}
iov_iter_ubuf(&kmsg->msg.msg_iter, ITER_DEST, buf, len);
}
kmsg->msg.msg_get_inq = 1;
kmsg->msg.msg_inq = -1;
if (req->flags & REQ_F_APOLL_MULTISHOT) {
ret = io_recvmsg_multishot(sock, sr, kmsg, flags,
&mshot_finished);