Give struct socket structures a ref counting interface similar to

vnodes.  This will hopefully serve as a base from which we can
expand the MP code.  We currently do not attempt to obtain any
mutex or SX locks, but the door is open to add them when we nail
down exactly how that part of it is going to work.

1 files changed, 71 insertions, 134 deletions

diff --git a/sys/kern/uipc_syscalls.c b/sys/kern/uipc_syscalls.c
index a0ca7cc..ee68cfe 100644
--- a/sys/kern/uipc_syscalls.c
+++ b/sys/kern/uipc_syscalls.c
@@ -139,7 +139,7 @@ socket(td, uap)
 			fdrop(fp, td);
 		}
 	} else {
-		fp->f_data = (caddr_t)so;
+		fp->f_data = (caddr_t)so;	/* already has ref count */
 		fp->f_flag = FREAD|FWRITE;
 		fp->f_ops = &socketops;
 		fp->f_type = DTYPE_SOCKET;
@@ -164,22 +164,19 @@ bind(td, uap)
 		int	namelen;
 	} */ *uap;
 {
-	struct file *fp;
 	struct sockaddr *sa;
+	struct socket *sp;
 	int error;
 
 	mtx_lock(&Giant);
-	error = holdsock(td->td_proc->p_fd, uap->s, &fp);
-	if (error)
-		goto done2;
-	error = getsockaddr(&sa, uap->name, uap->namelen);
-	if (error) {
-		fdrop(fp, td);
+	if ((error = fgetsock(td, uap->s, &sp, NULL)) != 0)
 		goto done2;
-	}
-	error = sobind((struct socket *)fp->f_data, sa, td);
+	if ((error = getsockaddr(&sa, uap->name, uap->namelen)) != 0)
+		goto done1;
+	error = sobind(sp, sa, td);
 	FREE(sa, M_SONAME);
-	fdrop(fp, td);
+done1:
+	fputsock(sp);
 done2:
 	mtx_unlock(&Giant);
 	return (error);
@@ -197,14 +194,13 @@ listen(td, uap)
 		int	backlog;
 	} */ *uap;
 {
-	struct file *fp;
+	struct socket *sp;
 	int error;
 
 	mtx_lock(&Giant);
-	error = holdsock(td->td_proc->p_fd, uap->s, &fp);
-	if (error == 0) {
-		error = solisten((struct socket *)fp->f_data, uap->backlog, td);
-		fdrop(fp, td);
+	if ((error = fgetsock(td, uap->s, &sp, NULL)) == 0) {
+		error = solisten(sp, uap->backlog, td);
+		fputsock(sp);
 	}
 	mtx_unlock(&Giant);
 	return(error);
@@ -225,13 +221,12 @@ accept1(td, uap, compat)
 	int compat;
 {
 	struct filedesc *fdp;
-	struct file *lfp = NULL;
 	struct file *nfp = NULL;
 	struct sockaddr *sa;
 	int namelen, error, s;
 	struct socket *head, *so;
 	int fd;
-	short fflag;		/* type must match fp->f_flag */
+	u_int fflag;
 
 	mtx_lock(&Giant);
 	fdp = td->td_proc->p_fd;
@@ -241,11 +236,10 @@ accept1(td, uap, compat)
 		if(error)
 			goto done2;
 	}
-	error = holdsock(fdp, uap->s, &lfp);
+	error = fgetsock(td, uap->s, &head, &fflag);
 	if (error)
 		goto done2;
 	s = splnet();
-	head = (struct socket *)lfp->f_data;
 	if ((head->so_options & SO_ACCEPTCONN) == 0) {
 		splx(s);
 		error = EINVAL;
@@ -286,7 +280,6 @@ accept1(td, uap, compat)
 	TAILQ_REMOVE(&head->so_comp, so, so_list);
 	head->so_qlen--;
 
-	fflag = lfp->f_flag;
 	error = falloc(td, &nfp, &fd);
 	if (error) {
 		/*
@@ -312,7 +305,8 @@ accept1(td, uap, compat)
 	if (head->so_sigio != NULL)
 		fsetown(fgetown(head->so_sigio), &so->so_sigio);
 
-	nfp->f_data = (caddr_t)so;
+	soref(so);			/* file descriptor reference */
+	nfp->f_data = (caddr_t)so;	/* nfp has ref count from falloc */
 	nfp->f_flag = fflag;
 	nfp->f_ops = &socketops;
 	nfp->f_type = DTYPE_SOCKET;
@@ -375,7 +369,7 @@ noconnection:
 done:
 	if (nfp != NULL)
 		fdrop(nfp, td);
-	fdrop(lfp, td);
+	fputsock(head);
 done2:
 	mtx_unlock(&Giant);
 	return (error);
@@ -420,35 +414,31 @@ connect(td, uap)
 		int	namelen;
 	} */ *uap;
 {
-	struct file *fp;
-	register struct socket *so;
+	struct socket *so;
 	struct sockaddr *sa;
 	int error, s;
 
 	mtx_lock(&Giant);
-	error = holdsock(td->td_proc->p_fd, uap->s, &fp);
-	if (error)
+	if ((error = fgetsock(td, uap->s, &so, NULL)) != 0)
 		goto done2;
-	so = (struct socket *)fp->f_data;
 	if ((so->so_state & SS_NBIO) && (so->so_state & SS_ISCONNECTING)) {
 		error = EALREADY;
-		goto done;
+		goto done1;
 	}
 	error = getsockaddr(&sa, uap->name, uap->namelen);
 	if (error)
-		goto done;
+		goto done1;
 	error = soconnect(so, sa, td);
 	if (error)
 		goto bad;
 	if ((so->so_state & SS_NBIO) && (so->so_state & SS_ISCONNECTING)) {
 		FREE(sa, M_SONAME);
 		error = EINPROGRESS;
-		goto done;
+		goto done1;
 	}
 	s = splnet();
 	while ((so->so_state & SS_ISCONNECTING) && so->so_error == 0) {
-		error = tsleep((caddr_t)&so->so_timeo, PSOCK | PCATCH,
-		    "connec", 0);
+		error = tsleep((caddr_t)&so->so_timeo, PSOCK | PCATCH, "connec", 0);
 		if (error)
 			break;
 	}
@@ -462,8 +452,8 @@ bad:
 	FREE(sa, M_SONAME);
 	if (error == ERESTART)
 		error = EINTR;
-done:
-	fdrop(fp, td);
+done1:
+	fputsock(so);
 done2:
 	mtx_unlock(&Giant);
 	return (error);
@@ -499,12 +489,12 @@ socketpair(td, uap)
 		goto free2;
 	fhold(fp1);
 	sv[0] = fd;
-	fp1->f_data = (caddr_t)so1;
+	fp1->f_data = (caddr_t)so1;	/* so1 already has ref count */
 	error = falloc(td, &fp2, &fd);
 	if (error)
 		goto free3;
 	fhold(fp2);
-	fp2->f_data = (caddr_t)so2;
+	fp2->f_data = (caddr_t)so2;	/* so2 already has ref count */
 	sv[1] = fd;
 	error = soconnect2(so1, so2);
 	if (error)
@@ -552,12 +542,11 @@ sendit(td, s, mp, flags)
 	register struct msghdr *mp;
 	int flags;
 {
-	struct file *fp;
 	struct uio auio;
 	register struct iovec *iov;
 	register int i;
 	struct mbuf *control;
-	struct sockaddr *to;
+	struct sockaddr *to = NULL;
 	int len, error;
 	struct socket *so;
 #ifdef KTRACE
@@ -565,8 +554,7 @@ sendit(td, s, mp, flags)
 	struct uio ktruio;
 #endif
 
-	error = holdsock(td->td_proc->p_fd, s, &fp);
-	if (error)
+	if ((error = fgetsock(td, s, &so, NULL)) != 0)
 		return (error);
 	auio.uio_iov = mp->msg_iov;
 	auio.uio_iovcnt = mp->msg_iovlen;
@@ -578,18 +566,14 @@ sendit(td, s, mp, flags)
 	iov = mp->msg_iov;
 	for (i = 0; i < mp->msg_iovlen; i++, iov++) {
 		if ((auio.uio_resid += iov->iov_len) < 0) {
-			fdrop(fp, td);
-			return (EINVAL);
+			error = EINVAL;
+			goto bad;
 		}
 	}
 	if (mp->msg_name) {
 		error = getsockaddr(&to, mp->msg_name, mp->msg_namelen);
-		if (error) {
-			fdrop(fp, td);
-			return (error);
-		}
-	} else {
-		to = 0;
+		if (error)
+			goto bad;
 	}
 	if (mp->msg_control) {
 		if (mp->msg_controllen < sizeof(struct cmsghdr)
@@ -633,7 +617,6 @@ sendit(td, s, mp, flags)
 	}
 #endif
 	len = auio.uio_resid;
-	so = (struct socket *)fp->f_data;
 	error = so->so_proto->pr_usrreqs->pru_sosend(so, to, &auio, 0, control,
 						     flags, td);
 	if (error) {
@@ -659,7 +642,7 @@ sendit(td, s, mp, flags)
 	}
 #endif
 bad:
-	fdrop(fp, td);
+	fputsock(so);
 	if (to)
 		FREE(to, M_SONAME);
 	return (error);
@@ -834,7 +817,6 @@ recvit(td, s, mp, namelenp)
 	register struct msghdr *mp;
 	caddr_t namelenp;
 {
-	struct file *fp;
 	struct uio auio;
 	register struct iovec *iov;
 	register int i;
@@ -848,8 +830,7 @@ recvit(td, s, mp, namelenp)
 	struct uio ktruio;
 #endif
 
-	error = holdsock(td->td_proc->p_fd, s, &fp);
-	if (error)
+	if ((error = fgetsock(td, s, &so, NULL)) != 0)
 		return (error);
 	auio.uio_iov = mp->msg_iov;
 	auio.uio_iovcnt = mp->msg_iovlen;
@@ -861,7 +842,7 @@ recvit(td, s, mp, namelenp)
 	iov = mp->msg_iov;
 	for (i = 0; i < mp->msg_iovlen; i++, iov++) {
 		if ((auio.uio_resid += iov->iov_len) < 0) {
-			fdrop(fp, td);
+			fputsock(so);
 			return (EINVAL);
 		}
 	}
@@ -875,7 +856,6 @@ recvit(td, s, mp, namelenp)
 	}
 #endif
 	len = auio.uio_resid;
-	so = (struct socket *)fp->f_data;
 	error = so->so_proto->pr_usrreqs->pru_soreceive(so, &fromsa, &auio,
 	    (struct mbuf **)0, mp->msg_control ? &control : (struct mbuf **)0,
 	    &mp->msg_flags);
@@ -975,7 +955,7 @@ recvit(td, s, mp, namelenp)
 		mp->msg_controllen = ctlbuf - (caddr_t)mp->msg_control;
 	}
 out:
-	fdrop(fp, td);
+	fputsock(so);
 	if (fromsa)
 		FREE(fromsa, M_SONAME);
 	if (control)
@@ -1196,14 +1176,13 @@ shutdown(td, uap)
 		int	how;
 	} */ *uap;
 {
-	struct file *fp;
+	struct socket *so;
 	int error;
 
 	mtx_lock(&Giant);
-	error = holdsock(td->td_proc->p_fd, uap->s, &fp);
-	if (error == 0) {
-		error = soshutdown((struct socket *)fp->f_data, uap->how);
-		fdrop(fp, td);
+	if ((error = fgetsock(td, uap->s, &so, NULL)) == 0) {
+		error = soshutdown(so, uap->how);
+		fputsock(so);
 	}
 	mtx_unlock(&Giant);
 	return(error);
@@ -1224,7 +1203,7 @@ setsockopt(td, uap)
 		int	valsize;
 	} */ *uap;
 {
-	struct file *fp;
+	struct socket *so;
 	struct sockopt sopt;
 	int error;
 
@@ -1234,16 +1213,15 @@ setsockopt(td, uap)
 		return (EINVAL);
 
 	mtx_lock(&Giant);
-	error = holdsock(td->td_proc->p_fd, uap->s, &fp);
-	if (error == 0) {
+	if ((error = fgetsock(td, uap->s, &so, NULL)) == 0) {
 		sopt.sopt_dir = SOPT_SET;
 		sopt.sopt_level = uap->level;
 		sopt.sopt_name = uap->name;
 		sopt.sopt_val = uap->val;
 		sopt.sopt_valsize = uap->valsize;
 		sopt.sopt_td = td;
-		error = sosetopt((struct socket *)fp->f_data, &sopt);
-		fdrop(fp, td);
+		error = sosetopt(so, &sopt);
+		fputsock(so);
 	}
 	mtx_unlock(&Giant);
 	return(error);
@@ -1265,24 +1243,20 @@ getsockopt(td, uap)
 	} */ *uap;
 {
 	int	valsize, error;
-	struct	file *fp;
+	struct  socket *so;
 	struct	sockopt sopt;
 
 	mtx_lock(&Giant);
-	error = holdsock(td->td_proc->p_fd, uap->s, &fp);
-	if (error)
+	if ((error = fgetsock(td, uap->s, &so, NULL)) != 0)
 		goto done2;
 	if (uap->val) {
 		error = copyin((caddr_t)uap->avalsize, (caddr_t)&valsize,
 		    sizeof (valsize));
-		if (error) {
-			fdrop(fp, td);
-			goto done2;
-		}
+		if (error)
+			goto done1;
 		if (valsize < 0) {
-			fdrop(fp, td);
 			error = EINVAL;
-			goto done2;
+			goto done1;
 		}
 	} else {
 		valsize = 0;
@@ -1295,13 +1269,14 @@ getsockopt(td, uap)
 	sopt.sopt_valsize = (size_t)valsize; /* checked non-negative above */
 	sopt.sopt_td = td;
 
-	error = sogetopt((struct socket *)fp->f_data, &sopt);
+	error = sogetopt(so, &sopt);
 	if (error == 0) {
 		valsize = sopt.sopt_valsize;
 		error = copyout((caddr_t)&valsize,
 				(caddr_t)uap->avalsize, sizeof (valsize));
 	}
-	fdrop(fp, td);
+done1:
+	fputsock(so);
 done2:
 	mtx_unlock(&Giant);
 	return (error);
@@ -1323,21 +1298,16 @@ getsockname1(td, uap, compat)
 	} */ *uap;
 	int compat;
 {
-	struct file *fp;
-	register struct socket *so;
+	struct socket *so;
 	struct sockaddr *sa;
 	int len, error;
 
 	mtx_lock(&Giant);
-	error = holdsock(td->td_proc->p_fd, uap->fdes, &fp);
-	if (error)
+	if ((error = fgetsock(td, uap->fdes, &so, NULL)) != 0)
 		goto done2;
 	error = copyin((caddr_t)uap->alen, (caddr_t)&len, sizeof (len));
-	if (error) {
-		fdrop(fp, td);
-		goto done2;
-	}
-	so = (struct socket *)fp->f_data;
+	if (error)
+		goto done1;
 	sa = 0;
 	error = (*so->so_proto->pr_usrreqs->pru_sockaddr)(so, &sa);
 	if (error)
@@ -1360,7 +1330,8 @@ gotnothing:
 bad:
 	if (sa)
 		FREE(sa, M_SONAME);
-	fdrop(fp, td);
+done1:
+	fputsock(so);
 done2:
 	mtx_unlock(&Giant);
 	return (error);
@@ -1408,26 +1379,20 @@ getpeername1(td, uap, compat)
 	} */ *uap;
 	int compat;
 {
-	struct file *fp;
-	register struct socket *so;
+	struct socket *so;
 	struct sockaddr *sa;
 	int len, error;
 
 	mtx_lock(&Giant);
-	error = holdsock(td->td_proc->p_fd, uap->fdes, &fp);
-	if (error)
+	if ((error = fgetsock(td, uap->fdes, &so, NULL)) != 0)
 		goto done2;
-	so = (struct socket *)fp->f_data;
 	if ((so->so_state & (SS_ISCONNECTED|SS_ISCONFIRMING)) == 0) {
-		fdrop(fp, td);
 		error = ENOTCONN;
-		goto done2;
+		goto done1;
 	}
 	error = copyin((caddr_t)uap->alen, (caddr_t)&len, sizeof (len));
-	if (error) {
-		fdrop(fp, td);
-		goto done2;
-	}
+	if (error)
+		goto done1;
 	sa = 0;
 	error = (*so->so_proto->pr_usrreqs->pru_peeraddr)(so, &sa);
 	if (error)
@@ -1450,7 +1415,8 @@ gotnothing:
 bad:
 	if (sa)
 		FREE(sa, M_SONAME);
-	fdrop(fp, td);
+done1:
+	fputsock(so);
 done2:
 	mtx_unlock(&Giant);
 	return (error);
@@ -1550,33 +1516,6 @@ getsockaddr(namp, uaddr, len)
 }
 
 /*
- * holdsock() - load the struct file pointer associated
- * with a socket into *fpp.  If an error occurs, non-zero
- * will be returned and *fpp will be set to NULL.
- */
-int
-holdsock(fdp, fdes, fpp)
-	struct filedesc *fdp;
-	int fdes;
-	struct file **fpp;
-{
-	register struct file *fp = NULL;
-	int error = 0;
-
-	if ((unsigned)fdes >= fdp->fd_nfiles ||
-	    (fp = fdp->fd_ofiles[fdes]) == NULL) {
-		error = EBADF;
-	} else if (fp->f_type != DTYPE_SOCKET) {
-		error = ENOTSOCK;
-		fp = NULL;
-	} else {
-		fhold(fp);
-	}
-	*fpp = fp;
-	return(error);
-}
-
-/*
  * Allocate a pool of sf_bufs (sendfile(2) or "super-fast" if you prefer. :-))
  * XXX - The sf_buf functions are currently private to sendfile(2), so have
  * been made static, but may be useful in the future for doing zero-copy in
@@ -1678,10 +1617,9 @@ sf_buf_free(caddr_t addr, void *args)
 int
 sendfile(struct thread *td, struct sendfile_args *uap)
 {
-	struct file *fp = NULL;
 	struct vnode *vp;
 	struct vm_object *obj;
-	struct socket *so;
+	struct socket *so = NULL;
 	struct mbuf *m;
 	struct sf_buf *sf;
 	struct vm_page *pg;
@@ -1701,10 +1639,8 @@ sendfile(struct thread *td, struct sendfile_args *uap)
 		error = EINVAL;
 		goto done;
 	}
-	error = holdsock(td->td_proc->p_fd, uap->s, &fp);
-	if (error)
+	if ((error = fgetsock(td, uap->s, &so, NULL)) != 0)
 		goto done;
-	so = (struct socket *)fp->f_data;
 	if (so->so_type != SOCK_STREAM) {
 		error = EINVAL;
 		goto done;
@@ -1988,8 +1924,9 @@ done:
 	}
 	if (vp)
 		vrele(vp);
-	if (fp)
-		fdrop(fp, td);
+	if (so)
+		fputsock(so);
 	mtx_unlock(&Giant);
 	return (error);
 }
+