Does FreeBSD have sendmmsg or recvmmsg system calls?
Boris Astardzhiev
boris.astardzhiev at gmail.com
Mon Jan 25 09:22:16 UTC 2016
kb>You defer to ppoll() and pselect() due to the struct timespec type of
kb>the argument, am I right ?
Yes.
kb>BTW, just noted, I think the functions should live in libc/gen.
Okay. Moving them.
kb>Put each sentence on new line
Done.
kb>The CMTR define is only used once. I do not see why not inline it, and
kb>get rid of the staircase of backslashes.
Initially I wrote two CMTRs - one using pselect and the other using ppoll.
I left it this way to easily switch between these and that's why I have
this macro. I'll inline the code as suggested.
kb>Also, it seems that the next unused bit is 0x80000.
I noticed that as well and fixed it.
kb>Still int for msg_len ?
I'll convert it to ssize_t.
kb>It probably makes sense to mark pointers with __restrict.
Done.
gj>This seems wrong. rcvd is initialized to 1 so that the check for
gj>rcvd != 0 can never be false. We already successfully called
gj>__sys_recvmsg() just above the loop, so why not simplify the
gj>code by doing
gj>
gj> if (ret == -1)
gj> return (rcvd);
Fixed.
On Sun, Jan 24, 2016 at 11:07 AM, Gary Jennejohn <gljennjohn at gmail.com>
wrote:
> On Sun, 24 Jan 2016 07:06:34 +0200
> Konstantin Belousov <kostikbel at gmail.com> wrote:
>
> [delete irrelevant parts of the patch]
>
> > > + rcvd = 1;
> > > + for (i = rcvd; i < vlen; i++) {
> > i = rcvd = 1; ... i++, rcvd++ ?
> >
> > > + ret = __sys_recvmsg(s, &msgvec[i].msg_hdr, flags);
> > > + if (ret == -1) {
> > > + if (rcvd != 0) {
> > > + /* We've received messages. Let caller
> know. */
>
> > > + return (rcvd);
> > > + }
> > > + return (ret);
> > > + }
> > > +
>
> This seems wrong. rcvd is initialized to 1 so that the check for
> rcvd != 0 can never be false. We already successfully called
> __sys_recvmsg() just above the loop, so why not simplify the
> code by doing
>
> if (ret == -1)
> return (rcvd);
>
> --
> Gary Jennejohn (gj@)
>
-------------- next part --------------
diff --git a/lib/libc/gen/Makefile.inc b/lib/libc/gen/Makefile.inc
index b448461..f9d2f8a 100644
--- a/lib/libc/gen/Makefile.inc
+++ b/lib/libc/gen/Makefile.inc
@@ -99,11 +99,13 @@ SRCS+= __getosreldate.c \
raise.c \
readdir.c \
readpassphrase.c \
+ recvmmsg.c \
rewinddir.c \
scandir.c \
seed48.c \
seekdir.c \
semctl.c \
+ sendmmsg.c \
setdomainname.c \
sethostname.c \
setjmperr.c \
diff --git a/lib/libc/gen/recvmmsg.c b/lib/libc/gen/recvmmsg.c
new file mode 100644
index 0000000..98835ba
--- /dev/null
+++ b/lib/libc/gen/recvmmsg.c
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2016 Boris Astardzhiev, Smartcom-Bulgaria AD
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice(s), this list of conditions and the following disclaimer as
+ * the first lines of this file unmodified other than the possible
+ * addition of one or more copyright notices.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice(s), this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/syscall.h>
+#include <sys/socket.h>
+#include <sys/select.h>
+#include <pthread.h>
+#include "libc_private.h"
+
+ssize_t
+recvmmsg(int s, struct mmsghdr *__restrict msgvec, size_t vlen, int flags,
+ const struct timespec *__restrict timeout)
+{
+ size_t i, rcvd;
+ ssize_t ret;
+
+ if (timeout != NULL) {
+ fd_set fds;
+ int res;
+
+ FD_ZERO(&fds);
+ FD_SET(s, &fds);
+ res = __sys_pselect(s + 1, &fds, NULL, NULL, timeout, NULL);
+ if (res == -1 || res == 0)
+ return (res);
+ if (!FD_ISSET(s, &fds))
+ return (-1);
+ }
+
+ ret = __sys_recvmsg(s, &msgvec[0].msg_hdr, flags);
+ if (ret == -1)
+ return (ret);
+
+ /* Check initially for the presence of MSG_WAITFORONE.
+ * Turn on MSG_DONTWAIT if set. */
+ if (flags & MSG_WAITFORONE) {
+ flags |= MSG_DONTWAIT;
+ /* The kernel doesn't need to know about this flag. */
+ flags &= ~MSG_WAITFORONE;
+ }
+
+ rcvd = 1;
+ for (i = rcvd; i < vlen; i++, rcvd++) {
+ ret = __sys_recvmsg(s, &msgvec[i].msg_hdr, flags);
+ if (ret == -1) {
+ /* We have received messages. Let caller know. */
+ return (rcvd);
+ }
+
+ /* Save received bytes */
+ msgvec[i].msg_len = ret;
+ }
+
+ return (rcvd);
+}
diff --git a/lib/libc/gen/sendmmsg.c b/lib/libc/gen/sendmmsg.c
new file mode 100644
index 0000000..e4e62a4
--- /dev/null
+++ b/lib/libc/gen/sendmmsg.c
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2016 Boris Astardzhiev, Smartcom-Bulgaria AD
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice(s), this list of conditions and the following disclaimer as
+ * the first lines of this file unmodified other than the possible
+ * addition of one or more copyright notices.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice(s), this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/syscall.h>
+#include <sys/socket.h>
+#include <pthread.h>
+#include "libc_private.h"
+
+ssize_t
+sendmmsg(int s, struct mmsghdr *__restrict msgvec, size_t vlen, int flags)
+{
+ size_t i, sent;
+ ssize_t ret;
+
+ sent = 0;
+ for (i = 0; i < vlen; i++, sent++) {
+ ret = __sys_sendmsg(s, &msgvec[i].msg_hdr, flags);
+ if (ret == -1) {
+ if (sent != 0) {
+ /* We have sent messages. Let caller know. */
+ return (sent);
+ }
+ return (ret);
+ }
+
+ /* Save sent bytes */
+ msgvec[i].msg_len = ret;
+ }
+
+ return (sent);
+}
diff --git a/lib/libc/include/namespace.h b/lib/libc/include/namespace.h
index 739d7b1..c95829e 100644
--- a/lib/libc/include/namespace.h
+++ b/lib/libc/include/namespace.h
@@ -208,6 +208,7 @@
#define readv _readv
#define recvfrom _recvfrom
#define recvmsg _recvmsg
+#define recvmmsg _recvmmsg
#define select _select
#define sem_close _sem_close
#define sem_destroy _sem_destroy
@@ -220,6 +221,7 @@
#define sem_unlink _sem_unlink
#define sem_wait _sem_wait
#define sendmsg _sendmsg
+#define sendmmsg _sendmmsg
#define sendto _sendto
#define setsockopt _setsockopt
/*#define sigaction _sigaction*/
diff --git a/lib/libc/include/un-namespace.h b/lib/libc/include/un-namespace.h
index f31fa7a..0233348 100644
--- a/lib/libc/include/un-namespace.h
+++ b/lib/libc/include/un-namespace.h
@@ -189,6 +189,7 @@
#undef readv
#undef recvfrom
#undef recvmsg
+#undef recvmmsg
#undef select
#undef sem_close
#undef sem_destroy
@@ -201,6 +202,7 @@
#undef sem_unlink
#undef sem_wait
#undef sendmsg
+#undef sendmmsg
#undef sendto
#undef setsockopt
#undef sigaction
diff --git a/lib/libc/sys/Symbol.map b/lib/libc/sys/Symbol.map
index 7b3257c..dc2ed0e 100644
--- a/lib/libc/sys/Symbol.map
+++ b/lib/libc/sys/Symbol.map
@@ -399,6 +399,8 @@ FBSD_1.4 {
utimensat;
numa_setaffinity;
numa_getaffinity;
+ sendmmsg;
+ recvmmsg;
};
FBSDprivate_1.0 {
diff --git a/lib/libc/sys/recv.2 b/lib/libc/sys/recv.2
index 326e7ff..e940364 100644
--- a/lib/libc/sys/recv.2
+++ b/lib/libc/sys/recv.2
@@ -34,8 +34,9 @@
.Sh NAME
.Nm recv ,
.Nm recvfrom ,
-.Nm recvmsg
-.Nd receive a message from a socket
+.Nm recvmsg ,
+.Nm recvmmsg
+.Nd receive message(s) from a socket
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
@@ -47,11 +48,15 @@
.Fn recvfrom "int s" "void *buf" "size_t len" "int flags" "struct sockaddr * restrict from" "socklen_t * restrict fromlen"
.Ft ssize_t
.Fn recvmsg "int s" "struct msghdr *msg" "int flags"
+.Ft ssize_t
+.Fn recvmmsg "int s" "struct mmsghdr * restrict msgvec" "size_t vlen" "int flags" "const struct timespec * restrict timeout"
.Sh DESCRIPTION
The
.Fn recvfrom
and
.Fn recvmsg
+and
+.Fn recvmmsg
system calls
are used to receive messages from a socket,
and may be used to receive data on a socket whether or not
@@ -84,8 +89,29 @@ null pointer passed as its
.Fa from
argument.
.Pp
-All three routines return the length of the message on successful
-completion.
+The
+.Fn recvmmsg
+function is used to receive multiple
+messages at a call.
+Their number is supplied by
+.Fa vlen .
+The messages are placed in the
+.Fa msgvec
+vector after reception.
+The size of each received message is placed in the
+.Fa msg_len
+field of each element of the vector.
+If
+.Fa timeout
+is NULL the call will normally block.
+Otherwise it will wait for data for the specified amount of time.
+If the timeout expires and there is no data received a value of 0 is returned.
+pselect(2) is used for the implementation of the timeout mechanism.
+.Pp
+The first three routines return the length of the message on successful
+completion whereas
+.Fn recvmmsg
+returns the number of received messages.
If a message is too long to fit in the supplied buffer,
excess bytes may be discarded depending on the type of socket
the message is received from (see
@@ -100,7 +126,9 @@ in which case the value
.Va errno
is set to
.Er EAGAIN .
-The receive calls normally return any data available,
+The receive calls except
+.Fn recvmmsg
+normally return any data available,
up to the requested amount,
rather than waiting for receipt of the full amount requested;
this behavior is affected by the socket-level options
@@ -127,6 +155,9 @@ one or more of the values:
.It Dv MSG_WAITALL Ta wait for full request or error
.It Dv MSG_DONTWAIT Ta do not block
.It Dv MSG_CMSG_CLOEXEC Ta set received fds close-on-exec
+.It Dv MSG_WAITFORONE Ta do not block after receiving the first message
+(relevant only for
+.Fn recvmmsg )
.El
.Pp
The
@@ -158,6 +189,11 @@ is set to
This flag is not available in strict
.Tn ANSI
or C99 compilation mode.
+The
+.Dv MSG_WAITFORONE
+flag sets MSG_DONTWAIT after the first message has been received.
+This flag is only relevant for
+.Fn recvmmsg .
.Pp
The
.Fn recvmsg
@@ -290,9 +326,33 @@ control data were discarded due to lack of space in the buffer
for ancillary data.
.Dv MSG_OOB
is returned to indicate that expedited or out-of-band data were received.
+.Pp
+The
+.Fn recvmmsg
+system call uses the
+.Fa mmsghdr
+structure. Its form is as follows, as defined in
+.In sys/socket.h :
+.Bd -literal
+struct mmsghdr {
+ struct msghdr msg_hdr; /* message header */
+ ssize_t msg_len; /* message length */
+};
+.Ed
+.Pp
+For
+.Fa msg_hdr
+see above. On data reception the
+.Fa msg_len
+field is updated to the length of the received message.
+On data transmission it is updated to the number of characters sent.
.Sh RETURN VALUES
-These calls return the number of bytes received, or -1
-if an error occurred.
+These calls except
+.Fn recvmmsg
+return the number of bytes received.
+.Fn recvmmsg
+returns the number of messages received.
+A value of -1 is returned if an error occurred.
.Sh ERRORS
The calls fail if:
.Bl -tag -width Er
diff --git a/lib/libc/sys/send.2 b/lib/libc/sys/send.2
index 8fa2c64..9810ace 100644
--- a/lib/libc/sys/send.2
+++ b/lib/libc/sys/send.2
@@ -34,8 +34,9 @@
.Sh NAME
.Nm send ,
.Nm sendto ,
-.Nm sendmsg
-.Nd send a message from a socket
+.Nm sendmsg ,
+.Nm sendmmsg
+.Nd send message(s) from a socket
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
@@ -47,6 +48,8 @@
.Fn sendto "int s" "const void *msg" "size_t len" "int flags" "const struct sockaddr *to" "socklen_t tolen"
.Ft ssize_t
.Fn sendmsg "int s" "const struct msghdr *msg" "int flags"
+.Ft ssize_t
+.Fn sendmmsg "int s" "struct mmsghdr * restrict msgvec" "size_t vlen" "int flags"
.Sh DESCRIPTION
The
.Fn send
@@ -55,8 +58,11 @@ and
.Fn sendto
and
.Fn sendmsg
+and
+.Fn sendmmsg
system calls
-are used to transmit a message to another socket.
+are used to transmit one or multiple messages (with the latter call) to
+another socket.
The
.Fn send
function
@@ -66,6 +72,8 @@ state, while
.Fn sendto
and
.Fn sendmsg
+and
+.Fn sendmmsg
may be used at any time.
.Pp
The address of the target is given by
@@ -81,6 +89,18 @@ underlying protocol, the error
is returned, and
the message is not transmitted.
.Pp
+The
+.Fn sendmmsg
+function sends multiple messages at a call.
+They are given by the
+.Fa msgvec
+vector along with
+.Fa vlen
+specifying its size.
+The number of characters sent per each message is placed in the
+.Fa msg_len
+field of each element of the vector after transmission.
+.Pp
No indication of failure to deliver is implicit in a
.Fn send .
Locally detected errors are indicated by a return value of -1.
@@ -138,10 +158,16 @@ See
.Xr recv 2
for a description of the
.Fa msghdr
+structure and the
+.Fa mmsghdr
structure.
.Sh RETURN VALUES
-The call returns the number of characters sent, or -1
-if an error occurred.
+All calls except
+.Fn sendmmsg
+return the number of characters sent. The
+.Fn sendmmsg
+call returns the number of messages sent.
+If an error occurred a value of -1 is returned.
.Sh ERRORS
The
.Fn send
@@ -149,6 +175,8 @@ function and
.Fn sendto
and
.Fn sendmsg
+and
+.Fn sendmmsg
system calls
fail if:
.Bl -tag -width Er
diff --git a/sys/sys/socket.h b/sys/sys/socket.h
index 18e2de1..c7a21cc 100644
--- a/sys/sys/socket.h
+++ b/sys/sys/socket.h
@@ -431,6 +431,9 @@ struct msghdr {
#define MSG_NBIO 0x4000 /* FIONBIO mode, used by fifofs */
#define MSG_COMPAT 0x8000 /* used in sendit() */
#define MSG_CMSG_CLOEXEC 0x40000 /* make received fds close-on-exec */
+#ifndef _KERNEL
+#define MSG_WAITFORONE 0x80000 /* for recvmmsg() */
+#endif /* !_KERNEL */
#endif
#ifdef _KERNEL
#define MSG_SOCALLBCK 0x10000 /* for use by socket callbacks - soreceive (TCP) */
@@ -595,6 +598,18 @@ struct sf_hdtr {
#endif /* _KERNEL */
#endif /* __BSD_VISIBLE */
+#ifndef _KERNEL
+#ifdef __BSD_VISIBLE
+/*
+ * Send/recvmmsg specific structure(s)
+ */
+struct mmsghdr {
+ struct msghdr msg_hdr; /* message header */
+ ssize_t msg_len; /* message length */
+};
+#endif /* __BSD_VISIBLE */
+#endif /* !_KERNEL */
+
#ifndef _KERNEL
#include <sys/cdefs.h>
@@ -615,11 +630,19 @@ int listen(int, int);
ssize_t recv(int, void *, size_t, int);
ssize_t recvfrom(int, void *, size_t, int, struct sockaddr * __restrict, socklen_t * __restrict);
ssize_t recvmsg(int, struct msghdr *, int);
+#if __BSD_VISIBLE
+struct timespec;
+ssize_t recvmmsg(int, struct mmsghdr * __restrict, size_t, int,
+ const struct timespec * __restrict);
+#endif
ssize_t send(int, const void *, size_t, int);
ssize_t sendto(int, const void *,
size_t, int, const struct sockaddr *, socklen_t);
ssize_t sendmsg(int, const struct msghdr *, int);
#if __BSD_VISIBLE
+ssize_t sendmmsg(int, struct mmsghdr * __restrict, size_t, int);
+#endif
+#if __BSD_VISIBLE
int sendfile(int, int, off_t, size_t, struct sf_hdtr *, off_t *, int);
int setfib(int);
#endif
More information about the freebsd-threads
mailing list