oops, don't want to remove mbufs while peeking!

[unix-history] / usr / src / sys / kern / uipc_socket.c

/*
* Copyright (c) 1982 Regents of the University of California.
* All rights reserved.  The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*
*      @(#)uipc_socket.c       6.20 (Berkeley) %G%
*/

#include "param.h"
#include "systm.h"
#include "dir.h"
#include "user.h"
#include "proc.h"
#include "file.h"
#include "inode.h"
#include "buf.h"
#include "mbuf.h"
#include "un.h"
#include "domain.h"
#include "protosw.h"
#include "socket.h"
#include "socketvar.h"
#include "stat.h"
#include "ioctl.h"
#include "uio.h"
#include "../net/route.h"
#include "../netinet/in.h"
#include "../net/if.h"

/*
* Socket operation routines.
* These routines are called by the routines in
* sys_socket.c or from a system process, and
* implement the semantics of socket operations by
* switching out to the protocol specific routines.
*
* TODO:
*      test socketpair
*      clean up async
*      out-of-band is a kludge
*/
/*ARGSUSED*/
socreate(dom, aso, type, proto)
       struct socket **aso;
       register int type;
       int proto;
{
       register struct protosw *prp;
       register struct socket *so;
       register struct mbuf *m;
       register int error;

       if (proto)
               prp = pffindproto(dom, proto, type);
       else
               prp = pffindtype(dom, type);
       if (prp == 0)
               return (EPROTONOSUPPORT);
       if (prp->pr_type != type)
               return (EPROTOTYPE);
       m = m_getclr(M_WAIT, MT_SOCKET);
       so = mtod(m, struct socket *);
       so->so_options = 0;
       so->so_state = 0;
       so->so_type = type;
       if (u.u_uid == 0)
               so->so_state = SS_PRIV;
       so->so_proto = prp;
       error =
           (*prp->pr_usrreq)(so, PRU_ATTACH,
               (struct mbuf *)0, (struct mbuf *)proto, (struct mbuf *)0);
       if (error) {
               so->so_state |= SS_NOFDREF;
               sofree(so);
               return (error);
       }
       *aso = so;
       return (0);
}

sobind(so, nam)
       struct socket *so;
       struct mbuf *nam;
{
       int s = splnet();
       int error;

       error =
           (*so->so_proto->pr_usrreq)(so, PRU_BIND,
               (struct mbuf *)0, nam, (struct mbuf *)0);
       splx(s);
       return (error);
}

solisten(so, backlog)
       register struct socket *so;
       int backlog;
{
       int s = splnet(), error;

       error =
           (*so->so_proto->pr_usrreq)(so, PRU_LISTEN,
               (struct mbuf *)0, (struct mbuf *)0, (struct mbuf *)0);
       if (error) {
               splx(s);
               return (error);
       }
       if (so->so_q == 0) {
               so->so_q = so;
               so->so_q0 = so;
               so->so_options |= SO_ACCEPTCONN;
       }
       if (backlog < 0)
               backlog = 0;
       so->so_qlimit = MIN(backlog, SOMAXCONN);
       splx(s);
       return (0);
}

sofree(so)
       register struct socket *so;
{

       if (so->so_head) {
               if (!soqremque(so, 0) && !soqremque(so, 1))
                       panic("sofree dq");
               so->so_head = 0;
       }
       if (so->so_pcb || (so->so_state & SS_NOFDREF) == 0)
               return;
       sbrelease(&so->so_snd);
       sorflush(so);
       (void) m_free(dtom(so));
}

/*
* Close a socket on last file table reference removal.
* Initiate disconnect if connected.
* Free socket when disconnect complete.
*/
soclose(so)
       register struct socket *so;
{
       int s = splnet();               /* conservative */
       int error;

       if (so->so_options & SO_ACCEPTCONN) {
               while (so->so_q0 != so)
                       (void) soabort(so->so_q0);
               while (so->so_q != so)
                       (void) soabort(so->so_q);
       }
       if (so->so_pcb == 0)
               goto discard;
       if (so->so_state & SS_ISCONNECTED) {
               if ((so->so_state & SS_ISDISCONNECTING) == 0) {
                       error = sodisconnect(so, (struct mbuf *)0);
                       if (error)
                               goto drop;
               }
               if (so->so_options & SO_LINGER) {
                       if ((so->so_state & SS_ISDISCONNECTING) &&
                           (so->so_state & SS_NBIO))
                               goto drop;
                       while (so->so_state & SS_ISCONNECTED)
                               sleep((caddr_t)&so->so_timeo, PZERO+1);
               }
       }
drop:
       if (so->so_pcb) {
               int error2 =
                   (*so->so_proto->pr_usrreq)(so, PRU_DETACH,
                       (struct mbuf *)0, (struct mbuf *)0, (struct mbuf *)0);
               if (error == 0)
                       error = error2;
       }
discard:
       if (so->so_state & SS_NOFDREF)
               panic("soclose: NOFDREF");
       so->so_state |= SS_NOFDREF;
       sofree(so);
       splx(s);
       return (error);
}

/*
* Must be called at splnet...
*/
soabort(so)
       struct socket *so;
{

       return (
           (*so->so_proto->pr_usrreq)(so, PRU_ABORT,
               (struct mbuf *)0, (struct mbuf *)0, (struct mbuf *)0));
}

soaccept(so, nam)
       register struct socket *so;
       struct mbuf *nam;
{
       int s = splnet();
       int error;

       if ((so->so_state & SS_NOFDREF) == 0)
               panic("soaccept: !NOFDREF");
       so->so_state &= ~SS_NOFDREF;
       error = (*so->so_proto->pr_usrreq)(so, PRU_ACCEPT,
           (struct mbuf *)0, nam, (struct mbuf *)0);
       splx(s);
       return (error);
}

soconnect(so, nam)
       register struct socket *so;
       struct mbuf *nam;
{
       int s = splnet();
       int error;

       /*
        * If protocol is connection-based, can only connect once.
        * Otherwise, if connected, try to disconnect first.
        * This allows user to disconnect by connecting to, e.g.,
        * a null address.
        */
       if (so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING) &&
           ((so->so_proto->pr_flags & PR_CONNREQUIRED) ||
           (error = sodisconnect(so))))
               error = EISCONN;
       else
               error = (*so->so_proto->pr_usrreq)(so, PRU_CONNECT,
                   (struct mbuf *)0, nam, (struct mbuf *)0);
       splx(s);
       return (error);
}

soconnect2(so1, so2)
       register struct socket *so1;
       struct socket *so2;
{
       int s = splnet();
       int error;

       error = (*so1->so_proto->pr_usrreq)(so1, PRU_CONNECT2,
           (struct mbuf *)0, (struct mbuf *)so2, (struct mbuf *)0);
       splx(s);
       return (error);
}

sodisconnect(so, nam)
       register struct socket *so;
       struct mbuf *nam;
{
       int s = splnet();
       int error;

       if ((so->so_state & SS_ISCONNECTED) == 0) {
               error = ENOTCONN;
               goto bad;
       }
       if (so->so_state & SS_ISDISCONNECTING) {
               error = EALREADY;
               goto bad;
       }
       error = (*so->so_proto->pr_usrreq)(so, PRU_DISCONNECT,
           (struct mbuf *)0, nam, (struct mbuf *)0);
bad:
       splx(s);
       return (error);
}

/*
* Send on a socket.
* If send must go all at once and message is larger than
* send buffering, then hard error.
* Lock against other senders.
* If must go all at once and not enough room now, then
* inform user that this would block and do nothing.
* Otherwise, if nonblocking, send as much as possible.
*/
sosend(so, nam, uio, flags, rights)
       register struct socket *so;
       struct mbuf *nam;
       register struct uio *uio;
       int flags;
       struct mbuf *rights;
{
       struct mbuf *top = 0;
       register struct mbuf *m, **mp;
       register int space;
       int len, rlen = 0, error = 0, s, dontroute, first = 1;

       if (sosendallatonce(so) && uio->uio_resid > so->so_snd.sb_hiwat)
               return (EMSGSIZE);
       dontroute =
           (flags & MSG_DONTROUTE) && (so->so_options & SO_DONTROUTE) == 0 &&
           (so->so_proto->pr_flags & PR_ATOMIC);
       u.u_ru.ru_msgsnd++;
       if (rights)
               rlen = rights->m_len;
#define snderr(errno)   { error = errno; splx(s); goto release; }

restart:
       sblock(&so->so_snd);
       do {
               s = splnet();
               if (so->so_state & SS_CANTSENDMORE)
                       snderr(EPIPE);
               if (so->so_error) {
                       error = so->so_error;
                       so->so_error = 0;                       /* ??? */
                       splx(s);
                       goto release;
               }
               if ((so->so_state & SS_ISCONNECTED) == 0) {
                       if (so->so_proto->pr_flags & PR_CONNREQUIRED)
                               snderr(ENOTCONN);
                       if (nam == 0)
                               snderr(EDESTADDRREQ);
               }
               if (flags & MSG_OOB)
                       space = 1024;
               else {
                       space = sbspace(&so->so_snd);
                       if (space <= rlen ||
                          (sosendallatonce(so) &&
                               space < uio->uio_resid + rlen) ||
                          (uio->uio_resid >= CLBYTES && space < CLBYTES &&
                          so->so_snd.sb_cc >= CLBYTES &&
                          (so->so_state & SS_NBIO) == 0)) {
                               if (so->so_state & SS_NBIO) {
                                       if (first)
                                               error = EWOULDBLOCK;
                                       splx(s);
                                       goto release;
                               }
                               sbunlock(&so->so_snd);
                               sbwait(&so->so_snd);
                               splx(s);
                               goto restart;
                       }
               }
               splx(s);
               mp = &top;
               space -= rlen;
               while (space > 0) {
                       register struct iovec *iov = uio->uio_iov;

                       MGET(m, M_WAIT, MT_DATA);
                       if (iov->iov_len >= NBPG && space >= CLBYTES) {
                               register struct mbuf *p;
                               MCLGET(p, 1);
                               if (p == 0)
                                       goto nopages;
                               m->m_off = (int)p - (int)m;
                               len = MIN(CLBYTES, iov->iov_len);
                               space -= CLBYTES;
                       } else {
nopages:
                               len = MIN(MIN(MLEN, iov->iov_len), space);
                               space -= len;
                       }
                       error = uiomove(mtod(m, caddr_t), len, UIO_WRITE, uio);
                       m->m_len = len;
                       *mp = m;
                       if (error)
                               goto release;
                       mp = &m->m_next;
                       if (uio->uio_resid <= 0)
                               break;
                       while (uio->uio_iov->iov_len == 0) {
                               uio->uio_iov++;
                               uio->uio_iovcnt--;
                               if (uio->uio_iovcnt <= 0)
                                       panic("sosend");
                       }
               }
               if (dontroute)
                       so->so_options |= SO_DONTROUTE;
               s = splnet();                                   /* XXX */
               error = (*so->so_proto->pr_usrreq)(so,
                   (flags & MSG_OOB) ? PRU_SENDOOB : PRU_SEND,
                   top, (caddr_t)nam, rights);
               splx(s);
               if (dontroute)
                       so->so_options &= ~SO_DONTROUTE;
               rights = 0;
               rlen = 0;
               top = 0;
               first = 0;
               if (error)
                       break;
       } while (uio->uio_resid);

release:
       sbunlock(&so->so_snd);
       if (top)
               m_freem(top);
       if (error == EPIPE)
               psignal(u.u_procp, SIGPIPE);
       return (error);
}

/*
* Implement receive operations on a socket.
* We depend on the way that records are added to the sockbuf
* by sbappend*.  In particular, each record (mbufs linked through m_next)
* must begin with an address if the protocol so specifies,
* followed by an optional mbuf containing access rights if supported
* by the protocol, and then zero or more mbufs of data.
* In order to avoid blocking network interrupts for the entire time here,
* we splx() while doing the actual copy to user space.
* Although the sockbuf is locked, new data may still be appended,
* and thus we must maintain consistency of the sockbuf during that time.
*/
soreceive(so, aname, uio, flags, rightsp)
       register struct socket *so;
       struct mbuf **aname;
       register struct uio *uio;
       int flags;
       struct mbuf **rightsp;
{
       register struct mbuf *m, *n;
       register int len, error = 0, s, tomark;
       struct protosw *pr = so->so_proto;
       struct mbuf *nextrecord;
       int moff;

       if (rightsp)
               *rightsp = 0;
       if (aname)
               *aname = 0;
       if (flags & MSG_OOB) {
               m = m_get(M_WAIT, MT_DATA);
               error = (*pr->pr_usrreq)(so, PRU_RCVOOB,
                   m, (struct mbuf *)(flags & MSG_PEEK), (struct mbuf *)0);
               if (error)
                       goto bad;
               do {
                       len = uio->uio_resid;
                       if (len > m->m_len)
                               len = m->m_len;
                       error =
                           uiomove(mtod(m, caddr_t), (int)len, UIO_READ, uio);
                       m = m_free(m);
               } while (uio->uio_resid && error == 0 && m);
bad:
               if (m)
                       m_freem(m);
               return (error);
       }

restart:
       sblock(&so->so_rcv);
       s = splnet();

#define rcverr(errno)   { error = errno; splx(s); goto release; }
       if (so->so_rcv.sb_cc == 0) {
               if (so->so_error) {
                       error = so->so_error;
                       so->so_error = 0;
                       splx(s);
                       goto release;
               }
               if (so->so_state & SS_CANTRCVMORE) {
                       splx(s);
                       goto release;
               }
               if ((so->so_state & SS_ISCONNECTED) == 0 &&
                   (so->so_proto->pr_flags & PR_CONNREQUIRED))
                       rcverr(ENOTCONN);
               if (uio->uio_resid == 0)
                       goto release;
               if (so->so_state & SS_NBIO)
                       rcverr(EWOULDBLOCK);
               sbunlock(&so->so_rcv);
               sbwait(&so->so_rcv);
               splx(s);
               goto restart;
       }
       u.u_ru.ru_msgrcv++;
       m = so->so_rcv.sb_mb;
       if (m == 0)
               panic("receive 1");
       nextrecord = m->m_act;
       if (pr->pr_flags & PR_ADDR) {
               if (m->m_type != MT_SONAME)
                       panic("receive 1a");
               if (flags & MSG_PEEK) {
                       if (aname)
                               *aname = m_copy(m, 0, m->m_len);
                       m = m->m_next;
               } else {
                       sbfree(&so->so_rcv, m);
                       if (aname) {
                               *aname = m;
                               m = m->m_next;
                               (*aname)->m_next = 0;
                       } else {
                               MFREE(m, n);
                               nextrecord = m->m_act;
                               m = n;
                       }
               }
       }
       if (m && m->m_type == MT_RIGHTS) {
               if ((pr->pr_flags & PR_RIGHTS) == 0)
                       panic("receive 2a");
               if (flags & MSG_PEEK) {
                       if (rightsp)
                               *rightsp = m_copy(m, 0, m->m_len);
                       m = m->m_next;
               } else {
                       sbfree(&so->so_rcv, m);
                       if (rightsp) {
                               *rightsp = m;
                               n = m->m_next;
                               m->m_next = 0;
                               m = n;
                       } else {
                               MFREE(m, n);
                               m = n;
                       }
               }
       }
       moff = 0;
       tomark = so->so_oobmark;
       while (m && uio->uio_resid > 0 && error == 0) {
               if (m->m_type != MT_DATA && m->m_type != MT_HEADER)
                       panic("receive 3");
               len = uio->uio_resid;
               so->so_state &= ~SS_RCVATMARK;
               if (tomark && len > tomark)
                       len = tomark;
               if (len > m->m_len - moff)
                       len = m->m_len - moff;
               if ((flags & MSG_PEEK) == 0) {
                       so->so_rcv.sb_mb = m;
                       m->m_act = nextrecord;
               }
               splx(s);
               error =
                   uiomove(mtod(m, caddr_t) + moff, (int)len, UIO_READ, uio);
               s = splnet();
               if (len == m->m_len - moff) {
                       if (flags & MSG_PEEK) {
                               m = m->m_next;
                               moff = 0;
                       } else {
                               sbfree(&so->so_rcv, m);
                               nextrecord = m->m_act;
                               MFREE(m, n);
                               so->so_rcv.sb_mb = m = n;
                       }
               } else {
                       if (flags & MSG_PEEK)
                               moff += len;
                       else {
                               m->m_off += len;
                               m->m_len -= len;
                               so->so_rcv.sb_cc -= len;
                       }
               }
               if ((flags & MSG_PEEK) == 0 && so->so_oobmark) {
                       so->so_oobmark -= len;
                       if (so->so_oobmark == 0) {
                               so->so_state |= SS_RCVATMARK;
                               break;
                       }
               }
               if (tomark) {
                       tomark -= len;
                       if (tomark == 0)
                               break;
               }
       }
       if ((flags & MSG_PEEK) == 0) {
               if (so->so_rcv.sb_mb == 0)
                       so->so_rcv.sb_mb = nextrecord;
               else if (pr->pr_flags & PR_ATOMIC)
                       (void) sbdroprecord(&so->so_rcv);
               if (pr->pr_flags & PR_WANTRCVD && so->so_pcb)
                       (*pr->pr_usrreq)(so, PRU_RCVD, (struct mbuf *)0,
                           (struct mbuf *)0, (struct mbuf *)0);
               if (error == 0 && rightsp && *rightsp &&
                   pr->pr_domain->dom_externalize)
                       error = (*pr->pr_domain->dom_externalize)(*rightsp);
       }
release:
       sbunlock(&so->so_rcv);
       splx(s);
       return (error);
}

soshutdown(so, how)
       register struct socket *so;
       register int how;
{
       register struct protosw *pr = so->so_proto;

       how++;
       if (how & FREAD)
               sorflush(so);
       if (how & FWRITE)
               return ((*pr->pr_usrreq)(so, PRU_SHUTDOWN,
                   (struct mbuf *)0, (struct mbuf *)0, (struct mbuf *)0));
       return (0);
}

sorflush(so)
       register struct socket *so;
{
       register struct sockbuf *sb = &so->so_rcv;
       register struct protosw *pr = so->so_proto;
       register int s;
       struct sockbuf asb;

       sblock(sb);
       s = splimp();
       socantrcvmore(so);
       sbunlock(sb);
       asb = *sb;
       bzero((caddr_t)sb, sizeof (*sb));
       splx(s);
       if (pr->pr_flags & PR_RIGHTS && pr->pr_domain->dom_dispose)
               (*pr->pr_domain->dom_dispose)(asb.sb_mb);
       sbrelease(&asb);
}

sosetopt(so, level, optname, m0)
       register struct socket *so;
       int level, optname;
       struct mbuf *m0;
{
       int error = 0;
       register struct mbuf *m = m0;

       if (level != SOL_SOCKET) {
               if (so->so_proto && so->so_proto->pr_ctloutput)
                       return ((*so->so_proto->pr_ctloutput)
                                 (PRCO_SETOPT, so, level, optname, &m0));
               error = ENOPROTOOPT;
       } else {
               switch (optname) {

               case SO_LINGER:
                       if (m == NULL || m->m_len != sizeof (struct linger)) {
                               error = EINVAL;
                               goto bad;
                       }
                       so->so_linger = mtod(m, struct linger *)->l_linger;
                       /* fall thru... */

               case SO_DEBUG:
               case SO_KEEPALIVE:
               case SO_DONTROUTE:
               case SO_USELOOPBACK:
               case SO_BROADCAST:
               case SO_REUSEADDR:
                       if (m == NULL || m->m_len < sizeof (int)) {
                               error = EINVAL;
                               goto bad;
                       }
                       if (*mtod(m, int *))
                               so->so_options |= optname;
                       else
                               so->so_options &= ~optname;
                       break;

               case SO_SNDBUF:
               case SO_RCVBUF:
               case SO_SNDLOWAT:
               case SO_RCVLOWAT:
               case SO_SNDTIMEO:
               case SO_RCVTIMEO:
                       if (m == NULL || m->m_len < sizeof (int)) {
                               error = EINVAL;
                               goto bad;
                       }
                       switch (optname) {

                       case SO_SNDBUF:
                       case SO_RCVBUF:
                               if (sbreserve(optname == SO_SNDBUF ? &so->so_snd :
                                   &so->so_rcv, *mtod(m, int *)) == 0) {
                                       error = ENOBUFS;
                                       goto bad;
                               }
                               break;

                       case SO_SNDLOWAT:
                               so->so_snd.sb_lowat = *mtod(m, int *);
                               break;
                       case SO_RCVLOWAT:
                               so->so_rcv.sb_lowat = *mtod(m, int *);
                               break;
                       case SO_SNDTIMEO:
                               so->so_snd.sb_timeo = *mtod(m, int *);
                               break;
                       case SO_RCVTIMEO:
                               so->so_rcv.sb_timeo = *mtod(m, int *);
                               break;
                       }
                       break;

               default:
                       error = ENOPROTOOPT;
                       break;
               }
       }
bad:
       if (m)
               (void) m_free(m);
       return (error);
}

sogetopt(so, level, optname, mp)
       register struct socket *so;
       int level, optname;
       struct mbuf **mp;
{
       register struct mbuf *m;

       if (level != SOL_SOCKET) {
               if (so->so_proto && so->so_proto->pr_ctloutput) {
                       return ((*so->so_proto->pr_ctloutput)
                                 (PRCO_GETOPT, so, level, optname, mp));
               } else 
                       return (ENOPROTOOPT);
       } else {
               m = m_get(M_WAIT, MT_SOOPTS);
               m->m_len = sizeof (int);

               switch (optname) {

               case SO_LINGER:
                       m->m_len = sizeof (struct linger);
                       mtod(m, struct linger *)->l_onoff =
                               so->so_options & SO_LINGER;
                       mtod(m, struct linger *)->l_linger = so->so_linger;
                       break;

               case SO_USELOOPBACK:
               case SO_DONTROUTE:
               case SO_DEBUG:
               case SO_KEEPALIVE:
               case SO_REUSEADDR:
               case SO_BROADCAST:
                       *mtod(m, int *) = so->so_options & optname;
                       break;

               case SO_TYPE:
                       *mtod(m, int *) = so->so_type;
                       break;

               case SO_ERROR:
                       *mtod(m, int *) = so->so_error;
                       so->so_error = 0;
                       break;

               case SO_SNDBUF:
                       *mtod(m, int *) = so->so_snd.sb_hiwat;
                       break;

               case SO_RCVBUF:
                       *mtod(m, int *) = so->so_rcv.sb_hiwat;
                       break;

               case SO_SNDLOWAT:
                       *mtod(m, int *) = so->so_snd.sb_lowat;
                       break;

               case SO_RCVLOWAT:
                       *mtod(m, int *) = so->so_rcv.sb_lowat;
                       break;

               case SO_SNDTIMEO:
                       *mtod(m, int *) = so->so_snd.sb_timeo;
                       break;

               case SO_RCVTIMEO:
                       *mtod(m, int *) = so->so_rcv.sb_timeo;
                       break;

               default:
                       m_free(m);
                       return (ENOPROTOOPT);
               }
               *mp = m;
               return (0);
       }
}

sohasoutofband(so)
       register struct socket *so;
{
       struct proc *p;

       if (so->so_pgrp < 0)
               gsignal(-so->so_pgrp, SIGURG);
       else if (so->so_pgrp > 0 && (p = pfind(so->so_pgrp)) != 0)
               psignal(p, SIGURG);
       if (so->so_rcv.sb_sel) {
               selwakeup(so->so_rcv.sb_sel, so->so_rcv.sb_flags & SB_COLL);
               so->so_rcv.sb_sel = 0;
               so->so_rcv.sb_flags &= ~SB_COLL;
       }
}