osmo_io: sendmsg/recvmsg support
Add support osmo_io operations resembling sendmsg() and recvmsg() socket
operations. This is what will enable the implementation of higher-layer
functions like equivalents of sctp_recvmsg() and sctp_send() in
libosmo-netif and/or other users.
Change-Id: I89eb519b22d21011d61a7855b2364bc3c295df82
Related: OS#5751
diff --git a/src/core/libosmocore.map b/src/core/libosmocore.map
index b66e37d..a50a9ed 100644
--- a/src/core/libosmocore.map
+++ b/src/core/libosmocore.map
@@ -266,7 +266,10 @@
osmo_iofd_ops;
osmo_iofd_register;
osmo_iofd_sendto_msgb;
+osmo_iofd_sctp_send_msgb;
+osmo_iofd_sendmsg_msgb;
osmo_iofd_set_alloc_info;
+osmo_iofd_set_cmsg_size;
osmo_iofd_set_data;
osmo_iofd_set_ioops;
osmo_iofd_set_priv_nr;
diff --git a/src/core/osmo_io.c b/src/core/osmo_io.c
index 71249cf..5d25f66 100644
--- a/src/core/osmo_io.c
+++ b/src/core/osmo_io.c
@@ -1,8 +1,8 @@
/*! \file osmo_io.c
* New osmocom async I/O API.
*
- * (C) 2022 by Harald Welte <laforge@osmocom.org>
- * (C) 2022-2023 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
+ * (C) 2022-2024 by Harald Welte <laforge@osmocom.org>
+ * (C) 2022-2024 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
* Author: Daniel Willmann <dwillmann@sysmocom.de>
*
* All Rights Reserved.
@@ -105,8 +105,10 @@
* \param[in] iofd the osmo_io file structure
* \param[in] action the action this msg(hdr) is for (read, write, ..)
* \param[in] msg the msg buffer to use. Will allocate a new one if NULL
+ * \param[in] cmsg_size size (in bytes) of iofd_msghdr.cmsg buffer. Can be 0 if cmsg is not used.
* \returns the newly allocated msghdr or NULL in case of error */
-struct iofd_msghdr *iofd_msghdr_alloc(struct osmo_io_fd *iofd, enum iofd_msg_action action, struct msgb *msg)
+struct iofd_msghdr *iofd_msghdr_alloc(struct osmo_io_fd *iofd, enum iofd_msg_action action, struct msgb *msg,
+ size_t cmsg_size)
{
bool free_msg = false;
struct iofd_msghdr *hdr;
@@ -120,7 +122,7 @@
talloc_steal(iofd, msg);
}
- hdr = talloc_zero(iofd, struct iofd_msghdr);
+ hdr = talloc_zero_size(iofd, sizeof(struct iofd_msghdr) + cmsg_size);
if (!hdr) {
if (free_msg)
talloc_free(msg);
@@ -339,8 +341,10 @@
case OSMO_IO_FD_MODE_RECVFROM_SENDTO:
iofd->io_ops.recvfrom_cb(iofd, rc, msg, &hdr->osa);
break;
- case OSMO_IO_FD_MODE_SCTP_RECVMSG_SEND:
- /* TODO Implement */
+ case OSMO_IO_FD_MODE_RECVMSG_SENDMSG:
+ iofd->io_ops.recvmsg_cb(iofd, rc, msg, &hdr->hdr);
+ break;
+ default:
OSMO_ASSERT(false);
break;
}
@@ -378,6 +382,9 @@
case IOFD_ACT_SENDTO:
iofd->io_ops.sendto_cb(iofd, rc, msg, &msghdr->osa);
break;
+ case IOFD_ACT_SENDMSG:
+ iofd->io_ops.sendmsg_cb(iofd, rc, msg);
+ break;
default:
OSMO_ASSERT(0);
}
@@ -408,7 +415,7 @@
return -EINVAL;
}
- struct iofd_msghdr *msghdr = iofd_msghdr_alloc(iofd, IOFD_ACT_WRITE, msg);
+ struct iofd_msghdr *msghdr = iofd_msghdr_alloc(iofd, IOFD_ACT_WRITE, msg, 0);
if (!msghdr)
return -ENOMEM;
@@ -450,7 +457,7 @@
return -EINVAL;
}
- struct iofd_msghdr *msghdr = iofd_msghdr_alloc(iofd, IOFD_ACT_SENDTO, msg);
+ struct iofd_msghdr *msghdr = iofd_msghdr_alloc(iofd, IOFD_ACT_SENDTO, msg, 0);
if (!msghdr)
return -ENOMEM;
@@ -475,16 +482,97 @@
return 0;
}
+/*! ismo_io equivalent of the sendmsg(2) socket API call
+ *
+ * Appends the message to the internal transmit queue.
+ * If the function returns success (0), it will take ownership of the msgb and
+ * internally call msgb_free() after the write request completes.
+ * In case of an error the msgb needs to be freed by the caller.
+ * \param[in] iofd file descriptor to write to
+ * \param[in] msg message buffer to send; is used to fill msgh->iov[]
+ * \param[in] sendmsg_flags Flags to pass to the send call
+ * \param[in] msgh 'struct msghdr' for name/control/flags. iov must be empty!
+ * \returns 0 in case of success; a negative value in case of error
+ */
+int osmo_iofd_sendmsg_msgb(struct osmo_io_fd *iofd, struct msgb *msg, int sendmsg_flags, const struct msghdr *msgh)
+{
+ int rc;
+ struct iofd_msghdr *msghdr;
+
+ OSMO_ASSERT(iofd->mode == OSMO_IO_FD_MODE_RECVMSG_SENDMSG);
+ if (OSMO_UNLIKELY(!iofd->io_ops.sendmsg_cb)) {
+ LOGPIO(iofd, LOGL_ERROR, "sendmsg_cb not set, Rejecting msgb\n");
+ return -EINVAL;
+ }
+
+ if (OSMO_UNLIKELY(msgh->msg_namelen > sizeof(msghdr->osa))) {
+ LOGPIO(iofd, LOGL_ERROR, "osmo_iofd_sendmsg msg_namelen (%u) > supported %zu bytes\n",
+ msgh->msg_namelen, sizeof(msghdr->osa));
+ return -EINVAL;
+ }
+
+ if (OSMO_UNLIKELY(msgh->msg_iovlen)) {
+ LOGPIO(iofd, LOGL_ERROR, "osmo_iofd_sendmsg must have all in 'struct msgb', not in 'msg_iov'\n");
+ return -EINVAL;
+ }
+
+ msghdr = iofd_msghdr_alloc(iofd, IOFD_ACT_SENDMSG, msg, msgh->msg_controllen);
+ if (!msghdr)
+ return -ENOMEM;
+
+ /* copy over optional address */
+ if (msgh->msg_name) {
+ memcpy(&msghdr->osa, msgh->msg_name, msgh->msg_namelen);
+ msghdr->hdr.msg_name = &msghdr->osa.u.sa;
+ msghdr->hdr.msg_namelen = msgh->msg_namelen;
+ }
+
+ /* build iov from msgb */
+ msghdr->iov[0].iov_base = msgb_data(msghdr->msg);
+ msghdr->iov[0].iov_len = msgb_length(msghdr->msg);
+ msghdr->hdr.msg_iov = &msghdr->iov[0];
+ msghdr->hdr.msg_iovlen = 1;
+
+ /* copy over the cmsg from the msghdr */
+ if (msgh->msg_control && msgh->msg_controllen) {
+ msghdr->hdr.msg_control = msghdr->cmsg;
+ msghdr->hdr.msg_controllen = msgh->msg_controllen;
+ memcpy(msghdr->cmsg, msgh->msg_control, msgh->msg_controllen);
+ }
+
+ /* copy over msg_flags */
+ msghdr->hdr.msg_flags = sendmsg_flags;
+
+ rc = iofd_txqueue_enqueue(iofd, msghdr);
+ if (rc < 0) {
+ iofd_msghdr_free(msghdr);
+ LOGPIO(iofd, LOGL_ERROR, "enqueueing message failed (%d). Rejecting msgb\n", rc);
+ return rc;
+ }
+
+ return 0;
+}
+
static int check_mode_callback_compat(enum osmo_io_fd_mode mode, const struct osmo_io_ops *ops)
{
switch (mode) {
case OSMO_IO_FD_MODE_READ_WRITE:
if (ops->recvfrom_cb || ops->sendto_cb)
return false;
+ if (ops->recvmsg_cb || ops->sendmsg_cb)
+ return false;
break;
case OSMO_IO_FD_MODE_RECVFROM_SENDTO:
if (ops->read_cb || ops->write_cb)
return false;
+ if (ops->recvmsg_cb || ops->sendmsg_cb)
+ return false;
+ break;
+ case OSMO_IO_FD_MODE_RECVMSG_SENDMSG:
+ if (ops->recvfrom_cb || ops->sendto_cb)
+ return false;
+ if (ops->read_cb || ops->write_cb)
+ return false;
break;
default:
break;
@@ -511,6 +599,7 @@
switch (mode) {
case OSMO_IO_FD_MODE_READ_WRITE:
case OSMO_IO_FD_MODE_RECVFROM_SENDTO:
+ case OSMO_IO_FD_MODE_RECVMSG_SENDMSG:
break;
default:
return NULL;
@@ -547,6 +636,16 @@
return iofd;
}
+/*! Set the size of the control message buffer allocated when submitting recvmsg */
+int osmo_iofd_set_cmsg_size(struct osmo_io_fd *iofd, size_t cmsg_size)
+{
+ if (iofd->mode != OSMO_IO_FD_MODE_RECVMSG_SENDMSG)
+ return -EINVAL;
+
+ iofd->cmsg_size = cmsg_size;
+ return 0;
+}
+
/*! Register the fd with the underlying backend.
*
* \param[in] iofd the iofd file descriptor
@@ -567,7 +666,8 @@
IOFD_FLAG_UNSET(iofd, IOFD_FLAG_CLOSED);
if ((iofd->mode == OSMO_IO_FD_MODE_READ_WRITE && iofd->io_ops.read_cb) ||
- (iofd->mode == OSMO_IO_FD_MODE_RECVFROM_SENDTO && iofd->io_ops.recvfrom_cb)) {
+ (iofd->mode == OSMO_IO_FD_MODE_RECVFROM_SENDTO && iofd->io_ops.recvfrom_cb) ||
+ (iofd->mode == OSMO_IO_FD_MODE_RECVMSG_SENDMSG && iofd->io_ops.recvmsg_cb)) {
osmo_iofd_ops.read_enable(iofd);
}
@@ -767,7 +867,12 @@
else
osmo_iofd_ops.read_disable(iofd);
break;
- case OSMO_IO_FD_MODE_SCTP_RECVMSG_SEND:
+ case OSMO_IO_FD_MODE_RECVMSG_SENDMSG:
+ if (iofd->io_ops.recvmsg_cb)
+ osmo_iofd_ops.read_enable(iofd);
+ else
+ osmo_iofd_ops.read_disable(iofd);
+ break;
default:
OSMO_ASSERT(0);
}
@@ -780,7 +885,8 @@
* \param[in] iofd the file descriptor */
void osmo_iofd_notify_connected(struct osmo_io_fd *iofd)
{
- OSMO_ASSERT(iofd->mode == OSMO_IO_FD_MODE_READ_WRITE);
+ OSMO_ASSERT(iofd->mode == OSMO_IO_FD_MODE_READ_WRITE ||
+ iofd->mode == OSMO_IO_FD_MODE_RECVMSG_SENDMSG);
OSMO_ASSERT(osmo_iofd_ops.notify_connected);
osmo_iofd_ops.notify_connected(iofd);
}
diff --git a/src/core/osmo_io_internal.h b/src/core/osmo_io_internal.h
index 9c86e05..af47a3d 100644
--- a/src/core/osmo_io_internal.h
+++ b/src/core/osmo_io_internal.h
@@ -4,6 +4,7 @@
#include <unistd.h>
#include <stdbool.h>
+#include <netinet/sctp.h>
#include <osmocom/core/osmo_io.h>
#include <osmocom/core/linuxlist.h>
@@ -72,6 +73,9 @@
/*! private number, extending \a data */
unsigned int priv_nr;
+ /*! size of iofd_msghdr.cmsg[] when allocated in recvmsg path */
+ size_t cmsg_size;
+
struct {
/*! talloc context from which to allocate msgb when reading */
const void *ctx;
@@ -109,7 +113,8 @@
IOFD_ACT_WRITE,
IOFD_ACT_RECVFROM,
IOFD_ACT_SENDTO,
- // TODO: SCTP_*
+ IOFD_ACT_RECVMSG,
+ IOFD_ACT_SENDMSG,
};
@@ -132,6 +137,9 @@
struct msgb *msg;
/*! I/O file descriptor on which we perform this I/O operation */
struct osmo_io_fd *iofd;
+
+ /*! control message buffer for passing sctp_sndrcvinfo along */
+ char cmsg[0]; /* size is determined by iofd->cmsg_size on recvmsg, and by mcghdr->msg_controllen on sendmsg */
};
enum iofd_seg_act {
@@ -140,7 +148,7 @@
IOFD_SEG_ACT_DEFER,
};
-struct iofd_msghdr *iofd_msghdr_alloc(struct osmo_io_fd *iofd, enum iofd_msg_action action, struct msgb *msg);
+struct iofd_msghdr *iofd_msghdr_alloc(struct osmo_io_fd *iofd, enum iofd_msg_action action, struct msgb *msg, size_t cmsg_size);
void iofd_msghdr_free(struct iofd_msghdr *msghdr);
struct msgb *iofd_msgb_alloc(struct osmo_io_fd *iofd);
diff --git a/src/core/osmo_io_poll.c b/src/core/osmo_io_poll.c
index 8398a30..52e806d 100644
--- a/src/core/osmo_io_poll.c
+++ b/src/core/osmo_io_poll.c
@@ -49,6 +49,7 @@
if (what & OSMO_FD_READ) {
struct iofd_msghdr hdr;
+
msg = iofd_msgb_pending_or_alloc(iofd);
if (!msg) {
LOGPIO(iofd, LOGL_ERROR, "Could not allocate msgb for reading\n");
@@ -64,6 +65,10 @@
.msg_name = &hdr.osa.u.sa,
.msg_namelen = sizeof(struct osmo_sockaddr),
};
+ if (iofd->mode == OSMO_IO_FD_MODE_RECVMSG_SENDMSG) {
+ hdr.hdr.msg_control = alloca(iofd->cmsg_size);
+ hdr.hdr.msg_controllen = iofd->cmsg_size;
+ }
rc = recvmsg(ofd->fd, &hdr.hdr, flags);
if (rc > 0)
@@ -90,13 +95,15 @@
case OSMO_IO_FD_MODE_RECVFROM_SENDTO:
iofd->io_ops.sendto_cb(iofd, 0, NULL, NULL);
break;
+ case OSMO_IO_FD_MODE_RECVMSG_SENDMSG:
+ iofd->io_ops.sendmsg_cb(iofd, 0, NULL);
+ break;
default:
break;
}
if (osmo_iofd_txqueue_len(iofd) == 0)
iofd_poll_ops.write_disable(iofd);
}
-
}
}
diff --git a/src/core/osmo_io_uring.c b/src/core/osmo_io_uring.c
index 24d1e08..aa9df85 100644
--- a/src/core/osmo_io_uring.c
+++ b/src/core/osmo_io_uring.c
@@ -3,6 +3,7 @@
*
* (C) 2022-2023 by sysmocom s.f.m.c.
* Author: Daniel Willmann <daniel@sysmocom.de>
+ * (C) 2023-2024 by Harald Welte <laforge@osmocom.org>
*
* All Rights Reserved.
*
@@ -35,6 +36,8 @@
#include <stdbool.h>
#include <errno.h>
+#include <netinet/in.h>
+#include <netinet/sctp.h>
#include <sys/eventfd.h>
#include <liburing.h>
@@ -114,7 +117,7 @@
OSMO_ASSERT(0);
}
- msghdr = iofd_msghdr_alloc(iofd, action, msg);
+ msghdr = iofd_msghdr_alloc(iofd, action, msg, iofd->cmsg_size);
if (!msghdr) {
LOGPIO(iofd, LOGL_ERROR, "Could not allocate msghdr for reading\n");
OSMO_ASSERT(0);
@@ -126,6 +129,10 @@
switch (action) {
case IOFD_ACT_READ:
break;
+ case IOFD_ACT_RECVMSG:
+ msghdr->hdr.msg_control = msghdr->cmsg;
+ msghdr->hdr.msg_controllen = iofd->cmsg_size;
+ /* fall-through */
case IOFD_ACT_RECVFROM:
msghdr->hdr.msg_iov = &msghdr->iov[0];
msghdr->hdr.msg_iovlen = 1;
@@ -146,6 +153,7 @@
case IOFD_ACT_READ:
io_uring_prep_readv(sqe, iofd->fd, msghdr->iov, 1, 0);
break;
+ case IOFD_ACT_RECVMSG:
case IOFD_ACT_RECVFROM:
io_uring_prep_recvmsg(sqe, iofd->fd, &msghdr->hdr, msghdr->flags);
break;
@@ -210,10 +218,12 @@
switch (msghdr->action) {
case IOFD_ACT_READ:
case IOFD_ACT_RECVFROM:
+ case IOFD_ACT_RECVMSG:
iofd_uring_handle_recv(msghdr, res);
break;
case IOFD_ACT_WRITE:
case IOFD_ACT_SENDTO:
+ case IOFD_ACT_SENDMSG:
iofd_uring_handle_tx(msghdr, res);
break;
default:
@@ -273,6 +283,7 @@
switch (msghdr->action) {
case IOFD_ACT_WRITE:
case IOFD_ACT_SENDTO:
+ case IOFD_ACT_SENDMSG:
io_uring_prep_sendmsg(sqe, msghdr->iofd->fd, &msghdr->hdr, msghdr->flags);
break;
default:
@@ -334,21 +345,20 @@
LOGPIO(iofd, LOGL_ERROR, "Could not allocate msgb for writing\n");
OSMO_ASSERT(0);
}
- msghdr = iofd_msghdr_alloc(iofd, IOFD_ACT_WRITE, msg);
+ msghdr = iofd_msghdr_alloc(iofd, IOFD_ACT_WRITE, msg, 0);
if (!msghdr) {
LOGPIO(iofd, LOGL_ERROR, "Could not allocate msghdr for writing\n");
OSMO_ASSERT(0);
}
msghdr->iov[0].iov_base = msgb_data(msg);
- msghdr->iov[0].iov_len = msgb_tailroom(msg);
+ msghdr->iov[0].iov_len = msgb_length(msg);
sqe = io_uring_get_sqe(&g_ring.ring);
if (!sqe) {
LOGPIO(iofd, LOGL_ERROR, "Could not get io_uring_sqe\n");
OSMO_ASSERT(0);
}
- // Prep msgb/iov
io_uring_prep_writev(sqe, iofd->fd, msghdr->iov, 1, 0);
io_uring_sqe_set_data(sqe, msghdr);
@@ -376,6 +386,9 @@
case OSMO_IO_FD_MODE_RECVFROM_SENDTO:
iofd_uring_submit_recv(iofd, IOFD_ACT_RECVFROM);
break;
+ case OSMO_IO_FD_MODE_RECVMSG_SENDMSG:
+ iofd_uring_submit_recv(iofd, IOFD_ACT_RECVMSG);
+ break;
default:
OSMO_ASSERT(0);
}