no more opt parameter to usrreq

[unix-history] / usr / src / sys / kern / uipc_socket2.c

/*      uipc_socket2.c  4.35    83/01/13        */

#include "../h/param.h"
#include "../h/systm.h"
#include "../h/dir.h"
#include "../h/user.h"
#include "../h/proc.h"
#include "../h/file.h"
#include "../h/inode.h"
#include "../h/buf.h"
#include "../h/mbuf.h"
#include "../h/protosw.h"
#include "../h/socket.h"
#include "../h/socketvar.h"

/*
* Primitive routines for operating on sockets and socket buffers
*/

/*
* Procedures to manipulate state flags of socket
* and do appropriate wakeups.  Normal sequence from the
* active (originating) side is that soisconnecting() is
* called during processing of connect() call,
* resulting in an eventual call to soisconnected() if/when the
* connection is established.  When the connection is torn down
* soisdisconnecting() is called during processing of disconnect() call,
* and soisdisconnected() is called when the connection to the peer
* is totally severed.  The semantics of these routines are such that
* connectionless protocols can call soisconnected() and soisdisconnected()
* only, bypassing the in-progress calls when setting up a ``connection''
* takes no time.
*
* From the passive side, a socket is created with SO_ACCEPTCONN
* creating two queues of sockets: so_q0 for connections in progress
* and so_q for connections already made and awaiting user acceptance.
* As a protocol is preparing incoming connections, it creates a socket
* structure queued on so_q0 by calling sonewconn().  When the connection
* is established, soisconnected() is called, and transfers the
* socket structure to so_q, making it available to accept().
* 
* If a SO_ACCEPTCONN socket is closed with sockets on either
* so_q0 or so_q, these sockets are dropped.
*
* If and when higher level protocols are implemented in
* the kernel, the wakeups done here will sometimes
* be implemented as software-interrupt process scheduling.
*/

soisconnecting(so)
       struct socket *so;
{

       so->so_state &= ~(SS_ISCONNECTED|SS_ISDISCONNECTING);
       so->so_state |= SS_ISCONNECTING;
       wakeup((caddr_t)&so->so_timeo);
}

soisconnected(so)
       struct socket *so;
{
       register struct socket *head = so->so_head;

       if (head) {
               if (soqremque(so, 0) == 0)
                       panic("soisconnected");
               soqinsque(head, so, 1);
               wakeup((caddr_t)&head->so_timeo);
       }
       so->so_state &= ~(SS_ISCONNECTING|SS_ISDISCONNECTING);
       so->so_state |= SS_ISCONNECTED;
       wakeup((caddr_t)&so->so_timeo);
       sorwakeup(so);
       sowwakeup(so);
}

soisdisconnecting(so)
       struct socket *so;
{

       so->so_state &= ~SS_ISCONNECTING;
       so->so_state |= (SS_ISDISCONNECTING|SS_CANTRCVMORE|SS_CANTSENDMORE);
       wakeup((caddr_t)&so->so_timeo);
       sowwakeup(so);
       sorwakeup(so);
}

soisdisconnected(so)
       struct socket *so;
{

       so->so_state &= ~(SS_ISCONNECTING|SS_ISCONNECTED|SS_ISDISCONNECTING);
       so->so_state |= (SS_CANTRCVMORE|SS_CANTSENDMORE);
       wakeup((caddr_t)&so->so_timeo);
       sowwakeup(so);
       sorwakeup(so);
}

/*
* When an attempt at a new connection is noted on a socket
* which accepts connections, sonewconn is called.  If the
* connection is possible (subject to space constraints, etc.)
* then we allocate a new structure, propoerly linked into the
* data structure of the original socket, and return this.
*/
struct socket *
sonewconn(head)
       register struct socket *head;
{
       register struct socket *so;
       struct mbuf *m;

       if (head->so_qlen + head->so_q0len > 3 * head->so_qlimit / 2)
               goto bad;
       m = m_getclr(M_DONTWAIT, MT_SOCKET);
       if (m == NULL)
               goto bad;
       so = mtod(m, struct socket *);
       so->so_type = head->so_type;
       so->so_options = head->so_options &~ SO_ACCEPTCONN;
       so->so_linger = head->so_linger;
       so->so_state = head->so_state | SS_NOFDREF;
       so->so_proto = head->so_proto;
       so->so_timeo = head->so_timeo;
       so->so_pgrp = head->so_pgrp;
       soqinsque(head, so, 0);
       if ((*so->so_proto->pr_usrreq)(so, PRU_ATTACH, (struct mbuf *)0,
         (struct mbuf *)0)) {
               (void) soqremque(so, 0);
               (void) m_free(m);
               goto bad;
       }
       return (so);
bad:
       return ((struct socket *)0);
}

soqinsque(head, so, q)
       register struct socket *head, *so;
       int q;
{

       so->so_head = head;
       if (q == 0) {
               head->so_q0len++;
               so->so_q0 = head->so_q0;
               head->so_q0 = so;
       } else {
               head->so_qlen++;
               so->so_q = head->so_q;
               head->so_q = so;
       }
}

soqremque(so, q)
       register struct socket *so;
       int q;
{
       register struct socket *head, *prev, *next;

       head = so->so_head;
       prev = head;
       for (;;) {
               next = q ? prev->so_q : prev->so_q0;
               if (next == so)
                       break;
               if (next == head)
                       return (0);
               prev = next;
       }
       if (q == 0) {
               prev->so_q0 = next->so_q0;
               head->so_q0len--;
       } else {
               prev->so_q = next->so_q;
               head->so_qlen--;
       }
       next->so_q0 = next->so_q = 0;
       next->so_head = 0;
       return (1);
}

/*
* Socantsendmore indicates that no more data will be sent on the
* socket; it would normally be applied to a socket when the user
* informs the system that no more data is to be sent, by the protocol
* code (in case PRU_SHUTDOWN).  Socantrcvmore indicates that no more data
* will be received, and will normally be applied to the socket by a
* protocol when it detects that the peer will send no more data.
* Data queued for reading in the socket may yet be read.
*/

socantsendmore(so)
       struct socket *so;
{

       so->so_state |= SS_CANTSENDMORE;
       sowwakeup(so);
}

socantrcvmore(so)
       struct socket *so;
{

       so->so_state |= SS_CANTRCVMORE;
       sorwakeup(so);
}

/*
* Socket select/wakeup routines.
*/

/*
* Interface routine to select() system
* call for sockets.
*/
soselect(so, rw)
       register struct socket *so;
       int rw;
{
       int s = splnet();

       switch (rw) {

       case FREAD:
               if (soreadable(so)) {
                       splx(s);
                       return (1);
               }
               sbselqueue(&so->so_rcv);
               break;

       case FWRITE:
               if (sowriteable(so)) {
                       splx(s);
                       return (1);
               }
               sbselqueue(&so->so_snd);
               break;
       }
       splx(s);
       return (0);
}

/*
* Queue a process for a select on a socket buffer.
*/
sbselqueue(sb)
       struct sockbuf *sb;
{
       register struct proc *p;

       if ((p = sb->sb_sel) && p->p_wchan == (caddr_t)&selwait)
               sb->sb_flags |= SB_COLL;
       else
               sb->sb_sel = u.u_procp;
}

/*
* Wait for data to arrive at/drain from a socket buffer.
*/
sbwait(sb)
       struct sockbuf *sb;
{

       sb->sb_flags |= SB_WAIT;
       sleep((caddr_t)&sb->sb_cc, PZERO+1);
}

/*
* Wakeup processes waiting on a socket buffer.
*/
sbwakeup(sb)
       struct sockbuf *sb;
{

       if (sb->sb_sel) {
               selwakeup(sb->sb_sel, sb->sb_flags & SB_COLL);
               sb->sb_sel = 0;
               sb->sb_flags &= ~SB_COLL;
       }
       if (sb->sb_flags & SB_WAIT) {
               sb->sb_flags &= ~SB_WAIT;
               wakeup((caddr_t)&sb->sb_cc);
       }
}

/*
* Socket buffer (struct sockbuf) utility routines.
*
* Each socket contains two socket buffers: one for sending data and
* one for receiving data.  Each buffer contains a queue of mbufs,
* information about the number of mbufs and amount of data in the
* queue, and other fields allowing select() statements and notification
* on data availability to be implemented.
*
* Before using a new socket structure it is first necessary to reserve
* buffer space to the socket, by calling sbreserve.  This commits
* some of the available buffer space in the system buffer pool for the
* socket.  The space should be released by calling sbrelease when the
* socket is destroyed.
*
* The routine sbappend() is normally called to append new mbufs
* to a socket buffer, after checking that adequate space is available
* comparing the function spspace() with the amount of data to be added.
* Data is normally removed from a socket buffer in a protocol by
* first calling m_copy on the socket buffer mbuf chain and sending this
* to a peer, and then removing the data from the socket buffer with
* sbdrop when the data is acknowledged by the peer (or immediately
* in the case of unreliable protocols.)
*
* Protocols which do not require connections place both source address
* and data information in socket buffer queues.  The source addresses
* are stored in single mbufs after each data item, and are easily found
* as the data items are all marked with end of record markers.  The
* sbappendaddr() routine stores a datum and associated address in
* a socket buffer.  Note that, unlike sbappend(), this routine checks
* for the caller that there will be enough space to store the data.
* It fails if there is not enough space, or if it cannot find
* a mbuf to store the address in.
*
* The higher-level routines sosend and soreceive (in socket.c)
* also add data to, and remove data from socket buffers repectively.
*/

soreserve(so, sndcc, rcvcc)
       struct socket *so;
       int sndcc, rcvcc;
{

       if (sbreserve(&so->so_snd, sndcc) == 0)
               goto bad;
       if (sbreserve(&so->so_rcv, rcvcc) == 0)
               goto bad2;
       return (0);
bad2:
       sbrelease(&so->so_snd);
bad:
       return (ENOBUFS);
}

/*
* Allot mbufs to a sockbuf.
*/
sbreserve(sb, cc)
       struct sockbuf *sb;
{

       /* someday maybe this routine will fail... */
       sb->sb_hiwat = cc;
       /* the 2 implies names can be no more than 1 mbuf each */
       sb->sb_mbmax = cc*2;
       return (1);
}

/*
* Free mbufs held by a socket, and reserved mbuf space.
*/
sbrelease(sb)
       struct sockbuf *sb;
{

       sbflush(sb);
       sb->sb_hiwat = sb->sb_mbmax = 0;
}

/*
* Routines to add (at the end) and remove (from the beginning)
* data from a mbuf queue.
*/

/*
* Append mbuf queue m to sockbuf sb.
*/
sbappend(sb, m)
       register struct mbuf *m;
       register struct sockbuf *sb;
{
       register struct mbuf *n;

       n = sb->sb_mb;
       if (n)
               while (n->m_next)
                       n = n->m_next;
       while (m) {
               if (m->m_len == 0 && (int)m->m_act == 0) {
                       m = m_free(m);
                       continue;
               }
               if (n && n->m_off <= MMAXOFF && m->m_off <= MMAXOFF &&
                  (int)n->m_act == 0 && (int)m->m_act == 0 &&
                  (n->m_off + n->m_len + m->m_len) <= MMAXOFF) {
                       bcopy(mtod(m, caddr_t), mtod(n, caddr_t) + n->m_len,
                           (unsigned)m->m_len);
                       n->m_len += m->m_len;
                       sb->sb_cc += m->m_len;
                       m = m_free(m);
                       continue;
               }
               sballoc(sb, m);
               if (n == 0)
                       sb->sb_mb = m;
               else
                       n->m_next = m;
               n = m;
               m = m->m_next;
               n->m_next = 0;
       }
}

/*
* Append data and address.
* Return 0 if no space in sockbuf or if
* can't get mbuf to stuff address in.
*/
sbappendaddr(sb, asa, m0)
       struct sockbuf *sb;
       struct sockaddr *asa;
       struct mbuf *m0;
{
       struct sockaddr *msa;
       register struct mbuf *m;
       register int len = sizeof (struct sockaddr);

       m = m0;
       if (m == 0)
               panic("sbappendaddr");
       for (;;) {
               len += m->m_len;
               if (m->m_next == 0) {
                       m->m_act = (struct mbuf *)1;
                       break;
               }
               m = m->m_next;
       }
       if (len > sbspace(sb))
               return (0);
       m = m_get(M_DONTWAIT, MT_SONAME);
       if (m == 0)
               return (0);
       m->m_len = sizeof (struct sockaddr);
       msa = mtod(m, struct sockaddr *);
       *msa = *asa;
       m->m_act = (struct mbuf *)1;
       sbappend(sb, m);
       sbappend(sb, m0);
       return (1);
}

#ifdef notdef
SBCHECK(sb, str)
       struct sockbuf *sb;
       char *str;
{
       register int cnt = sb->sb_cc;
       register int mbcnt = sb->sb_mbcnt;
       register struct mbuf *m;

       for (m = sb->sb_mb; m; m = m->m_next) {
               cnt -= m->m_len;
               mbcnt -= MSIZE;
               if (m->m_off > MMAXOFF)
                       mbcnt -= CLBYTES;
       }
       if (cnt || mbcnt) {
               printf("cnt %d mbcnt %d\n", cnt, mbcnt);
               panic(str);
       }
}
#endif

/*
* Free all mbufs on a sockbuf mbuf chain.
* Check that resource allocations return to 0.
*/
sbflush(sb)
       struct sockbuf *sb;
{

       if (sb->sb_flags & SB_LOCK)
               panic("sbflush");
       if (sb->sb_cc)
               sbdrop(sb, sb->sb_cc);
       if (sb->sb_cc || sb->sb_mbcnt || sb->sb_mb)
               panic("sbflush 2");
}

/*
* Drop data from (the front of) a sockbuf chain.
*/
sbdrop(sb, len)
       register struct sockbuf *sb;
       register int len;
{
       register struct mbuf *m = sb->sb_mb, *mn;

       while (len > 0) {
               if (m == 0)
                       panic("sbdrop");
               if (m->m_len > len) {
                       m->m_len -= len;
                       m->m_off += len;
                       sb->sb_cc -= len;
                       break;
               }
               len -= m->m_len;
               sbfree(sb, m);
               MFREE(m, mn);
               m = mn;
       }
       sb->sb_mb = m;
}