MFC of UDP socket enhancement for BIND?

Robert Watson rwatson at FreeBSD.org
Sun Mar 11 03:17:42 UTC 2007


On Wed, 7 Mar 2007, garcol at postino.it wrote:

>> For reference, the sosend_copyin.diff applies these changes:
>>
>>   src/sys/kern/uipc_socket.c:1.253, 1.254, 1.255
>
> Sorry, It's seem doesn't work ... . The function sosend_copyin() where Have 
> I to declare it?

socketvar.h:1.144 is missing from this patch; I've attached a revised version 
of sosend_dgram.diff that includes that change (prototype declaration of 
socketvar.h).

Thanks,

Robert N M Watson
Computer Laboratory
University of Cambridge
-------------- next part --------------
Index: kern/uipc_socket.c
===================================================================
RCS file: /data/fbsd-cvs/ncvs/src/sys/kern/uipc_socket.c,v
retrieving revision 1.242.2.8
diff -u -r1.242.2.8 uipc_socket.c
--- kern/uipc_socket.c	3 Feb 2007 04:01:22 -0000	1.242.2.8
+++ kern/uipc_socket.c	11 Mar 2007 03:12:21 -0000
@@ -584,7 +584,301 @@
 	return (error);
 }
 
+#ifdef ZERO_COPY_SOCKETS
+struct so_zerocopy_stats{
+	int size_ok;
+	int align_ok;
+	int found_ifp;
+};
+struct so_zerocopy_stats so_zerocp_stats = {0,0,0};
+#include <netinet/in.h>
+#include <net/route.h>
+#include <netinet/in_pcb.h>
+#include <vm/vm.h>
+#include <vm/vm_page.h>
+#include <vm/vm_object.h>
+#endif /*ZERO_COPY_SOCKETS*/
+
+/*
+ * sosend_copyin() accepts a uio and prepares an mbuf chain holding part or
+ * all of the data referenced by the uio.  If desired, it uses zero-copy.
+ * *space will be updated to reflect data copied in.
+ *
+ * NB: If atomic I/O is requested, the caller must already have checked that
+ * space can hold resid bytes.
+ *
+ * NB: In the event of an error, the caller may need to free the partial
+ * chain pointed to by *mpp.  The contents of both *uio and *space may be
+ * modified even in the case of an error.
+ */
+static int
+sosend_copyin(struct uio *uio, struct mbuf **retmp, int atomic, long *space,
+    int flags)
+{
+	struct mbuf *m, **mp, *top;
+	long len, resid;
+	int error;
+#ifdef ZERO_COPY_SOCKETS
+	int cow_send;
+#endif
+
+	*retmp = top = NULL;
+	mp = &top;
+	len = 0;
+	resid = uio->uio_resid;
+	error = 0;
+	do {
+#ifdef ZERO_COPY_SOCKETS
+		cow_send = 0;
+#endif /* ZERO_COPY_SOCKETS */
+		if (resid >= MINCLSIZE) {
+#ifdef ZERO_COPY_SOCKETS
+			if (top == NULL) {
+				MGETHDR(m, M_TRYWAIT, MT_DATA);
+				if (m == NULL) {
+					error = ENOBUFS;
+					goto out;
+				}
+				m->m_pkthdr.len = 0;
+				m->m_pkthdr.rcvif = NULL; 
+			} else {
+				MGET(m, M_TRYWAIT, MT_DATA);
+				if (m == NULL) {
+					error = ENOBUFS;
+					goto out;
+				}
+			}
+			if (so_zero_copy_send &&
+			    resid>=PAGE_SIZE &&
+			    *space>=PAGE_SIZE &&
+			    uio->uio_iov->iov_len>=PAGE_SIZE) {
+				so_zerocp_stats.size_ok++;
+				so_zerocp_stats.align_ok++;
+				cow_send = socow_setup(m, uio);
+				len = cow_send;
+			}
+			if (!cow_send) {
+				MCLGET(m, M_TRYWAIT);
+				if ((m->m_flags & M_EXT) == 0) {
+					m_free(m);
+					m = NULL;
+				} else {
+					len = min(min(MCLBYTES, resid),
+					    *space);
+				}
+			}
+#else /* ZERO_COPY_SOCKETS */
+			if (top == NULL) {
+				m = m_getcl(M_TRYWAIT, MT_DATA, M_PKTHDR);
+				m->m_pkthdr.len = 0;
+				m->m_pkthdr.rcvif = NULL;
+			} else
+				m = m_getcl(M_TRYWAIT, MT_DATA, 0);
+			len = min(min(MCLBYTES, resid), *space);
+#endif /* ZERO_COPY_SOCKETS */
+		} else {
+			if (top == NULL) {
+				m = m_gethdr(M_TRYWAIT, MT_DATA);
+				m->m_pkthdr.len = 0;
+				m->m_pkthdr.rcvif = NULL;
+
+				len = min(min(MHLEN, resid), *space);
+				/*
+				 * For datagram protocols, leave room
+				 * for protocol headers in first mbuf.
+				 */
+				if (atomic && m && len < MHLEN)
+					MH_ALIGN(m, len);
+			} else {
+				m = m_get(M_TRYWAIT, MT_DATA);
+				len = min(min(MLEN, resid), *space);
+			}
+		}
+		if (m == NULL) {
+			error = ENOBUFS;
+			goto out;
+		}
+
+		*space -= len;
+#ifdef ZERO_COPY_SOCKETS
+		if (cow_send)
+			error = 0;
+		else
+#endif /* ZERO_COPY_SOCKETS */
+		error = uiomove(mtod(m, void *), (int)len, uio);
+		resid = uio->uio_resid;
+		m->m_len = len;
+		*mp = m;
+		top->m_pkthdr.len += len;
+		if (error)
+			goto out;
+		mp = &m->m_next;
+		if (resid <= 0) {
+			if (flags & MSG_EOR)
+				top->m_flags |= M_EOR;
+			break;
+		}
+	} while (*space > 0 && atomic);
+out:
+	*retmp = top;
+	return (error);
+}
+
 #define	SBLOCKWAIT(f)	(((f) & MSG_DONTWAIT) ? M_NOWAIT : M_WAITOK)
+
+int
+sosend_dgram(so, addr, uio, top, control, flags, td)
+	struct socket *so;
+	struct sockaddr *addr;
+	struct uio *uio;
+	struct mbuf *top;
+	struct mbuf *control;
+	int flags;
+	struct thread *td;
+{
+	long space, resid;
+	int clen = 0, error, dontroute;
+	int atomic = sosendallatonce(so) || top;
+
+	KASSERT(so->so_type == SOCK_DGRAM, ("sodgram_send: !SOCK_DGRAM"));
+	KASSERT(so->so_proto->pr_flags & PR_ATOMIC,
+	    ("sodgram_send: !PR_ATOMIC"));
+
+	if (uio != NULL)
+		resid = uio->uio_resid;
+	else
+		resid = top->m_pkthdr.len;
+	/*
+	 * In theory resid should be unsigned.
+	 * However, space must be signed, as it might be less than 0
+	 * if we over-committed, and we must use a signed comparison
+	 * of space and resid.  On the other hand, a negative resid
+	 * causes us to loop sending 0-length segments to the protocol.
+	 *
+	 * Also check to make sure that MSG_EOR isn't used on SOCK_STREAM
+	 * type sockets since that's an error.
+	 */
+	if (resid < 0) {
+		error = EINVAL;
+		goto out;
+	}
+
+	dontroute =
+	    (flags & MSG_DONTROUTE) && (so->so_options & SO_DONTROUTE) == 0;
+	if (td != NULL)
+		td->td_proc->p_stats->p_ru.ru_msgsnd++;
+	if (control != NULL)
+		clen = control->m_len;
+
+	SOCKBUF_LOCK(&so->so_snd);
+	if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
+		SOCKBUF_UNLOCK(&so->so_snd);
+		error = EPIPE;
+		goto out;
+	}
+	if (so->so_error) {
+		error = so->so_error;
+		so->so_error = 0;
+		SOCKBUF_UNLOCK(&so->so_snd);
+		goto out;
+	}
+	if ((so->so_state & SS_ISCONNECTED) == 0) {
+		/*
+		 * `sendto' and `sendmsg' is allowed on a connection-
+		 * based socket if it supports implied connect.
+		 * Return ENOTCONN if not connected and no address is
+		 * supplied.
+		 */
+		if ((so->so_proto->pr_flags & PR_CONNREQUIRED) &&
+		    (so->so_proto->pr_flags & PR_IMPLOPCL) == 0) {
+			if ((so->so_state & SS_ISCONFIRMING) == 0 &&
+			    !(resid == 0 && clen != 0)) {
+				SOCKBUF_UNLOCK(&so->so_snd);
+				error = ENOTCONN;
+				goto out;
+			}
+		} else if (addr == NULL) {
+			if (so->so_proto->pr_flags & PR_CONNREQUIRED)
+				error = ENOTCONN;
+			else
+				error = EDESTADDRREQ;
+			SOCKBUF_UNLOCK(&so->so_snd);
+			goto out;
+		}
+	}
+
+	/*
+	 * Do we need MSG_OOB support in SOCK_DGRAM?  Signs here may be a
+	 * problem and need fixing.
+	 */
+	space = sbspace(&so->so_snd);
+	if (flags & MSG_OOB)
+		space += 1024;
+	space -= clen;
+	if (resid > space) {
+		error = EMSGSIZE;
+		goto out;
+	}
+	SOCKBUF_UNLOCK(&so->so_snd);
+	if (uio == NULL) {
+		resid = 0;
+		if (flags & MSG_EOR)
+			top->m_flags |= M_EOR;
+	} else {
+		error = sosend_copyin(uio, &top, atomic, &space, flags);
+		if (error)
+			goto out;
+		resid = uio->uio_resid;
+	}
+	KASSERT(resid == 0, ("sosend_dgram: resid != 0"));
+	/*
+	 * XXXRW: Frobbing SO_DONTROUTE here is even worse without sblock
+	 * than with.
+	 */
+	if (dontroute) {
+		SOCK_LOCK(so);
+		so->so_options |= SO_DONTROUTE;
+		SOCK_UNLOCK(so);
+	}
+	/*
+	 * XXX all the SBS_CANTSENDMORE checks previously
+	 * done could be out of date.  We could have recieved
+	 * a reset packet in an interrupt or maybe we slept
+	 * while doing page faults in uiomove() etc. We could
+	 * probably recheck again inside the locking protection
+	 * here, but there are probably other places that this
+	 * also happens.  We must rethink this.
+	 */
+	error = (*so->so_proto->pr_usrreqs->pru_send)(so,
+	    (flags & MSG_OOB) ? PRUS_OOB :
+	/*
+	 * If the user set MSG_EOF, the protocol
+	 * understands this flag and nothing left to
+	 * send then use PRU_SEND_EOF instead of PRU_SEND.
+	 */
+	    ((flags & MSG_EOF) &&
+	     (so->so_proto->pr_flags & PR_IMPLOPCL) &&
+	     (resid <= 0)) ?
+		PRUS_EOF :
+		/* If there is more to send set PRUS_MORETOCOME */
+		(resid > 0 && space > 0) ? PRUS_MORETOCOME : 0,
+		top, addr, control, td);
+	if (dontroute) {
+		SOCK_LOCK(so);
+		so->so_options &= ~SO_DONTROUTE;
+		SOCK_UNLOCK(so);
+	}
+	clen = 0;
+	control = NULL;
+	top = NULL;
+out:
+	if (top != NULL)
+		m_freem(top);
+	if (control != NULL)
+		m_freem(control);
+	return (error);
+}
+
 /*
  * Send on a socket.
  * If send must go all at once and message is larger than
@@ -602,22 +896,7 @@
  * must check for short counts if EINTR/ERESTART are returned.
  * Data and control buffers are freed on return.
  */
-
-#ifdef ZERO_COPY_SOCKETS
-struct so_zerocopy_stats{
-	int size_ok;
-	int align_ok;
-	int found_ifp;
-};
-struct so_zerocopy_stats so_zerocp_stats = {0,0,0};
-#include <netinet/in.h>
-#include <net/route.h>
-#include <netinet/in_pcb.h>
-#include <vm/vm.h>
-#include <vm/vm_page.h>
-#include <vm/vm_object.h>
-#endif /*ZERO_COPY_SOCKETS*/
-
+#define	snderr(errno)	{ error = (errno); goto release; }
 int
 sosend(so, addr, uio, top, control, flags, td)
 	struct socket *so;
@@ -628,14 +907,9 @@
 	int flags;
 	struct thread *td;
 {
-	struct mbuf **mp;
-	struct mbuf *m;
-	long space, len = 0, resid;
+	long space, resid;
 	int clen = 0, error, dontroute;
 	int atomic = sosendallatonce(so) || top;
-#ifdef ZERO_COPY_SOCKETS
-	int cow_send;
-#endif /* ZERO_COPY_SOCKETS */
 
 	if (uio != NULL)
 		resid = uio->uio_resid;
@@ -663,7 +937,6 @@
 		td->td_proc->p_stats->p_ru.ru_msgsnd++;
 	if (control != NULL)
 		clen = control->m_len;
-#define	snderr(errno)	{ error = (errno); goto release; }
 
 	SOCKBUF_LOCK(&so->so_snd);
 restart:
@@ -713,153 +986,61 @@
 			goto restart;
 		}
 		SOCKBUF_UNLOCK(&so->so_snd);
-		mp = &top;
 		space -= clen;
 		do {
-		    if (uio == NULL) {
-			/*
-			 * Data is prepackaged in "top".
-			 */
-			resid = 0;
-			if (flags & MSG_EOR)
-				top->m_flags |= M_EOR;
-		    } else do {
-#ifdef ZERO_COPY_SOCKETS
-			cow_send = 0;
-#endif /* ZERO_COPY_SOCKETS */
-			if (resid >= MINCLSIZE) {
-#ifdef ZERO_COPY_SOCKETS
-				if (top == NULL) {
-					MGETHDR(m, M_TRYWAIT, MT_DATA);
-					if (m == NULL) {
-						error = ENOBUFS;
-						SOCKBUF_LOCK(&so->so_snd);
-						goto release;
-					}
-					m->m_pkthdr.len = 0;
-					m->m_pkthdr.rcvif = NULL; 
-				} else {
-					MGET(m, M_TRYWAIT, MT_DATA);
-					if (m == NULL) {
-						error = ENOBUFS;
-						SOCKBUF_LOCK(&so->so_snd);
-						goto release;
-					}
-				}
-				if (so_zero_copy_send &&
-				    resid>=PAGE_SIZE &&
-				    space>=PAGE_SIZE &&
-				    uio->uio_iov->iov_len>=PAGE_SIZE) {
-					so_zerocp_stats.size_ok++;
-					so_zerocp_stats.align_ok++;
-					cow_send = socow_setup(m, uio);
-					len = cow_send;
-				}
-				if (!cow_send) {
-					MCLGET(m, M_TRYWAIT);
-					if ((m->m_flags & M_EXT) == 0) {
-						m_free(m);
-						m = NULL;
-					} else {
-						len = min(min(MCLBYTES, resid), space);
-					}
-				}
-#else /* ZERO_COPY_SOCKETS */
-				if (top == NULL) {
-					m = m_getcl(M_TRYWAIT, MT_DATA, M_PKTHDR);
-					m->m_pkthdr.len = 0;
-					m->m_pkthdr.rcvif = NULL;
-				} else
-					m = m_getcl(M_TRYWAIT, MT_DATA, 0);
-				len = min(min(MCLBYTES, resid), space);
-#endif /* ZERO_COPY_SOCKETS */
+			if (uio == NULL) {
+				resid = 0;
+				if (flags & MSG_EOR)
+					top->m_flags |= M_EOR;
 			} else {
-				if (top == NULL) {
-					m = m_gethdr(M_TRYWAIT, MT_DATA);
-					m->m_pkthdr.len = 0;
-					m->m_pkthdr.rcvif = NULL;
-
-					len = min(min(MHLEN, resid), space);
-					/*
-					 * For datagram protocols, leave room
-					 * for protocol headers in first mbuf.
-					 */
-					if (atomic && m && len < MHLEN)
-						MH_ALIGN(m, len);
-				} else {
-					m = m_get(M_TRYWAIT, MT_DATA);
-					len = min(min(MLEN, resid), space);
+				error = sosend_copyin(uio, &top, atomic,
+				    &space, flags);
+				if (error != 0) {
+					SOCKBUF_LOCK(&so->so_snd);
+					goto release;
 				}
+				resid = uio->uio_resid;
 			}
-			if (m == NULL) {
-				error = ENOBUFS;
-				SOCKBUF_LOCK(&so->so_snd);
-				goto release;
-			}
-
-			space -= len;
-#ifdef ZERO_COPY_SOCKETS
-			if (cow_send)
-				error = 0;
-			else
-#endif /* ZERO_COPY_SOCKETS */
-			error = uiomove(mtod(m, void *), (int)len, uio);
-			resid = uio->uio_resid;
-			m->m_len = len;
-			*mp = m;
-			top->m_pkthdr.len += len;
-			if (error) {
-				SOCKBUF_LOCK(&so->so_snd);
-				goto release;
-			}
-			mp = &m->m_next;
-			if (resid <= 0) {
-				if (flags & MSG_EOR)
-					top->m_flags |= M_EOR;
-				break;
+			if (dontroute) {
+				SOCK_LOCK(so);
+				so->so_options |= SO_DONTROUTE;
+				SOCK_UNLOCK(so);
 			}
-		    } while (space > 0 && atomic);
-		    if (dontroute) {
-			    SOCK_LOCK(so);
-			    so->so_options |= SO_DONTROUTE;
-			    SOCK_UNLOCK(so);
-		    }
-		    /*
-		     * XXX all the SBS_CANTSENDMORE checks previously
-		     * done could be out of date.  We could have recieved
-		     * a reset packet in an interrupt or maybe we slept
-		     * while doing page faults in uiomove() etc. We could
-		     * probably recheck again inside the locking protection
-		     * here, but there are probably other places that this
-		     * also happens.  We must rethink this.
-		     */
-		    error = (*so->so_proto->pr_usrreqs->pru_send)(so,
-			(flags & MSG_OOB) ? PRUS_OOB :
+			/*
+			 * XXX all the SBS_CANTSENDMORE checks previously
+			 * done could be out of date.  We could have recieved
+			 * a reset packet in an interrupt or maybe we slept
+			 * while doing page faults in uiomove() etc. We could
+			 * probably recheck again inside the locking protection
+			 * here, but there are probably other places that this
+			 * also happens.  We must rethink this.
+			 */
+			error = (*so->so_proto->pr_usrreqs->pru_send)(so,
+			    (flags & MSG_OOB) ? PRUS_OOB :
 			/*
 			 * If the user set MSG_EOF, the protocol
 			 * understands this flag and nothing left to
 			 * send then use PRU_SEND_EOF instead of PRU_SEND.
 			 */
-			((flags & MSG_EOF) &&
-			 (so->so_proto->pr_flags & PR_IMPLOPCL) &&
-			 (resid <= 0)) ?
+			    ((flags & MSG_EOF) &&
+			     (so->so_proto->pr_flags & PR_IMPLOPCL) &&
+			     (resid <= 0)) ?
 				PRUS_EOF :
 			/* If there is more to send set PRUS_MORETOCOME */
-			(resid > 0 && space > 0) ? PRUS_MORETOCOME : 0,
-			top, addr, control, td);
-		    if (dontroute) {
-			    SOCK_LOCK(so);
-			    so->so_options &= ~SO_DONTROUTE;
-			    SOCK_UNLOCK(so);
-		    }
-		    clen = 0;
-		    control = NULL;
-		    top = NULL;
-		    mp = &top;
-		    if (error) {
-			SOCKBUF_LOCK(&so->so_snd);
-			goto release;
-		    }
+			    (resid > 0 && space > 0) ? PRUS_MORETOCOME : 0,
+			    top, addr, control, td);
+			if (dontroute) {
+				SOCK_LOCK(so);
+				so->so_options &= ~SO_DONTROUTE;
+				SOCK_UNLOCK(so);
+			}
+			clen = 0;
+			control = NULL;
+			top = NULL;
+			if (error) {
+				SOCKBUF_LOCK(&so->so_snd);
+				goto release;
+			}
 		} while (resid && space > 0);
 		SOCKBUF_LOCK(&so->so_snd);
 	} while (resid);
@@ -877,6 +1058,7 @@
 		m_freem(control);
 	return (error);
 }
+#undef snderr
 
 /*
  * The part of soreceive() that implements reading non-inline out-of-band
Index: netinet/udp_usrreq.c
===================================================================
RCS file: /data/fbsd-cvs/ncvs/src/sys/netinet/udp_usrreq.c,v
retrieving revision 1.175.2.9
diff -u -r1.175.2.9 udp_usrreq.c
--- netinet/udp_usrreq.c	29 Dec 2006 19:25:49 -0000	1.175.2.9
+++ netinet/udp_usrreq.c	11 Mar 2007 03:12:22 -0000
@@ -1150,6 +1150,7 @@
 	.pru_disconnect =	udp_disconnect,
 	.pru_peeraddr =		udp_peeraddr,
 	.pru_send =		udp_send,
+	.pru_sosend =		sosend_dgram,
 	.pru_shutdown =		udp_shutdown,
 	.pru_sockaddr =		udp_sockaddr,
 	.pru_sosetlabel =	in_pcbsosetlabel
Index: sys/socketvar.h
===================================================================
RCS file: /data/fbsd-cvs/ncvs/src/sys/sys/socketvar.h,v
retrieving revision 1.141.2.1
diff -u -r1.141.2.1 socketvar.h
--- sys/socketvar.h	28 Jun 2006 14:33:47 -0000	1.141.2.1
+++ sys/socketvar.h	11 Mar 2007 03:13:25 -0000
@@ -533,6 +533,9 @@
 int	sosend(struct socket *so, struct sockaddr *addr, struct uio *uio,
 	    struct mbuf *top, struct mbuf *control, int flags,
 	    struct thread *td);
+int	sosend_dgram(struct socket *so, struct sockaddr *addr,
+	    struct uio *uio, struct mbuf *top, struct mbuf *control,
+	    int flags, struct thread *td);
 int	sosetopt(struct socket *so, struct sockopt *sopt);
 int	soshutdown(struct socket *so, int how);
 void	sotoxsocket(struct socket *so, struct xsocket *xso);


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