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Annotation of 43BSD/contrib/enet/net/enet.c, revision 1.1

1.1     ! root        1: /*      enet.c Stanford        25 April 1983 */
        !             2: 
        !             3: /*
        !             4:  *  Ethernet packet filter layer,
        !             5:  *     formerly: Ethernet interface driver
        !             6:  *
        !             7:  **********************************************************************
        !             8:  * HISTORY
        !             9:  * 7 October 1985      Jeff Mogul      Stanford
        !            10:  *     Removed ENMAXOPENS limitation; available minors are now
        !            11:  *     dynamically allocated to interfaces, out of pool of NENETFILTER
        !            12:  *     minors.
        !            13:  *     Certain arrays formerly in the enState structure are now global.
        !            14:  *     Depends on modified openi() function so that enetopen() need
        !            15:  *     only be called once.
        !            16:  *     Remove support for "kernel access", it won't ever be used again.
        !            17:  *     Added EIOCMFREE ioctl.
        !            18:  *
        !            19:  * 17 October 1984     Jeff Mogul      Stanford
        !            20:  *    More performance improvements:
        !            21:  *     Added ENF_CAND, ENF_COR, ENF_CNAND, and ENF_CNOR, short-circuit
        !            22:  *     operators, to make filters run faster.
        !            23:  *     All evaluate "(*sp++ == *sp++)":
        !            24:  *     ENF_CAND: returns false immediately if result is false, otherwise
        !            25:  *             continue
        !            26:  *     ENF_COR: returns true immediately if result is true, otherwise
        !            27:  *             continue
        !            28:  *     ENF_CNAND: returns true immediately if result is false, otherwise
        !            29:  *             continue
        !            30:  *     ENF_CNOR: returns false immediately if result is true, otherwise
        !            31:  *             continue
        !            32:  *     Also added ENF_NEQ to complement ENF_EQ
        !            33:  *    - Maintain count of received packets per filter, dynamically
        !            34:  *     re-organize filter queue to keep highly active filters in
        !            35:  *     front of queue (but maintaining priority order), if they are
        !            36:  *     "high priority" filters.
        !            37:  *
        !            38:  * 2 October 1984      Jeff Mogul      Stanford
        !            39:  *     Made a few changes to enDoFilter() to speed it up, since profiling
        !            40:  *     shows it to be rather popular:
        !            41:  *     - precompute maximum word in packet and address of end of
        !            42:  *     filters (thereby moving this code out of "inner loop").
        !            43:  *     - minor re-arrangement to avoid re-evaluating a
        !            44:  *     common subexpression.
        !            45:  *     - changed #ifdef DEBUG in a few routines to #ifdef INNERDEBUG,
        !            46:  *     so that code in inner loops isn't always testing the enDebug
        !            47:  *     flag; this not only costs directly, but also breaks up some
        !            48:  *     basic blocks that the optimizer could play with.
        !            49:  *     - added enOneCopy flag; if true, then never deliver more than
        !            50:  *     one copy of a packet.  This is equivalent to giving everyone
        !            51:  *     a "high priority" device, and cuts down the number of superfluous
        !            52:  *     calls to enDoFilter(). [Temporary hack, will remove this!]
        !            53:  *
        !            54:  * 24 August 1984      Jeff Mogul      Stanford
        !            55:  *     YA bug with sleeping in enetwrite(); straightened out handling
        !            56:  *     of counts in enKludgeSleep so that they indicate the number
        !            57:  *     of sleeps in progress. Maybe I've got this right, now?
        !            58:  *     Also, don't sleep forever (since the net might be down).
        !            59:  *
        !            60:  * 17 July 1984        Jeff Mogul      Stanford
        !            61:  *     Bug fix: in enetwrite(), several problems with sleeping on
        !            62:  *     IF_QFULL:
        !            63:  *     - don't do it for kernel mode writes.
        !            64:  *     - count # of procs sleeping, to avoid lost wakeups.  Old
        !            65:  *             scheme would only wake up the first sleeper.
        !            66:  *     - using sleeper-count, avoid using more than one timeout
        !            67:  *             table entry per device; old scheme caused timeout table panics
        !            68:  *     - trap interupted sleeps using setjmp, so that we can deallocate
        !            69:  *             packet header and mbufs; otherwise we lost them and panicked.
        !            70:  *
        !            71:  * 5 July 1984 Jeff Mogul      Stanford
        !            72:  *     Bug fix: in enetwrite() make sure enP_RefCount is zero before
        !            73:  *     deallocating "packet".  Otherwise, "packets" get lost, and
        !            74:  *     take mbufs (and ultimately, the system) with them.
        !            75:  *
        !            76:  * 8 December 1983     Jeffrey Mogul   Stanford
        !            77:  *     Fixed bug in enetwrite() that eventually caused allocator
        !            78:  *     to run out of packets and panic.  If enetwrite() returns
        !            79:  *     an error it should first deallocate any packets it has allocated.
        !            80:  *
        !            81:  * 10 November 1983    Jeffrey Mogul   Stanford
        !            82:  *     Slight restructuring for support of 10mb ethers;
        !            83:  *     - added the EIOCDEVP ioctl
        !            84:  *     - removed the EIOCMTU ioctl (subsumed by EIOCDEVP)
        !            85:  *     This requires an additional parameter to the enetattach
        !            86:  *     call so that the device driver can specify things.
        !            87:  *
        !            88:  *     Also, cleaned up the enDebug scheme by adding symbolic
        !            89:  *     definitions for the bits.
        !            90:  *
        !            91:  * 25-Apr-83   Jeffrey Mogul   Stanford
        !            92:  *     Began conversion to 4.2BSD.  This involves removing all
        !            93:  *             references to the actual hardware.
        !            94:  *     Changed read/write interface to use uio scheme.
        !            95:  *     Changed ioctl interface to "new style"; this places a hard
        !            96:  *             limit on the size of a filter (about 128 bytes).
        !            97:  *     "Packets" now point to mbufs, not private buffers.
        !            98:  *     Filter can only access data in first mbuf (about 50 words worst case);
        !            99:  *             this is long enough for all Pup purposes.
        !           100:  *     Added EIOCMTU ioctl to get MTU (max packet size).
        !           101:  *     Added an enetselect() routine and other select() support.
        !           102:  *     Other stuff is (more or less) left intact.
        !           103:  *     Most previous history comments removed.
        !           104:  *     Changed some names from enXXXX to enetXXXX to avoid confusion(?)
        !           105:  *
        !           106:  * 10-Aug-82  Mike Accetta (mja) at Carnegie-Mellon University
        !           107:  *     Added new EIOCMBIS and EIOCMBIC ioctl calls to set and clear
        !           108:  *     bits in mode word;  added mode bit ENHOLDSIG which suppresses
        !           109:  *     the resetting of an enabled signal after it is sent (to be
        !           110:  *     used inconjunction with the SIGHOLD mechanism);  changed
        !           111:  *     EIOCGETP to zero pad word for future compatibility;  changed enwrite()
        !           112:  *     to enforce correct source host address on output packets (V3.05e).
        !           113:  *     (Stanford already uses long timeout value and has no pad word - JCM)
        !           114:  *     [Last change before 4.2BSD conversion starts.]
        !           115:  *
        !           116:  * 01-Dec-81  Mike Accetta (mja) at Carnegie-Mellon University
        !           117:  *     Fixed bug in timeout handling caused by missing "break" in the
        !           118:  *     "switch" state check within enetread().  This caused all reads
        !           119:  *     to be preceeded by a bogus timeout.  In addition, fixed another
        !           120:  *     bug in signal processing by also recording process ID of
        !           121:  *     process to signal when an input packet is available.  This is
        !           122:  *     necessary because it is possible for a process with an enabled
        !           123:  *     signal to fork and exit with no guarantee that the child will
        !           124:  *     reenable the signal.  Thus under appropriately bizarre race
        !           125:  *     conditions, an incoming packet to the child can cause a signal
        !           126:  *     to be sent to the unsuspecting process which inherited the
        !           127:  *     process slot of the parent.  Of course, if the PID's wrap around
        !           128:  *     AND the inheriting process has the same PID, well ... (V3.03d).
        !           129:  *
        !           130:  * 22-Feb-80  Rick Rashid (rfr) at Carnegie-Mellon University
        !           131:  *     Rewritten to provide multiple user access via user settable
        !           132:  *     filters (V1.05).
        !           133:  *
        !           134:  * 18-Jan-80  Mike Accetta (mja) at Carnegie-Mellon University
        !           135:  *      Created (V1.00).
        !           136:  *
        !           137:  **********************************************************************
        !           138:  */
        !           139: 
        !           140: #include "en.h"
        !           141: #include "ec.h"
        !           142: #include "il.h"
        !           143: #include "de.h"
        !           144: #include "enetfilter.h"
        !           145: 
        !           146: /* number of potential units */
        !           147: #define        NENET   (NEC + NEN + NIL + NDE)
        !           148: 
        !           149: #if (NENETFILTER > 0)
        !           150: 
        !           151: #define        SUN_OPENI
        !           152: 
        !           153: #include "param.h"
        !           154: #include "systm.h"
        !           155: #include "mbuf.h"
        !           156: #include "buf.h"
        !           157: #include "dir.h"
        !           158: #include "user.h"
        !           159: #include "ioctl.h"
        !           160: #include "map.h"
        !           161: #include "proc.h"
        !           162: #include "inode.h"
        !           163: #include "file.h"
        !           164: #include "tty.h"
        !           165: #include "uio.h"
        !           166: 
        !           167: #include "protosw.h"
        !           168: #include "socket.h"
        !           169: #include "../net/if.h"
        !           170: 
        !           171: #undef queue
        !           172: #undef dequeue
        !           173: #include "../net/enet.h"
        !           174: #include "../net/enetdefs.h"
        !           175: 
        !           176: #if    (NENETFILTER < 32)
        !           177: #undef NENETFILTER
        !           178: #define        NENETFILTER     32
        !           179: #endif
        !           180: 
        !           181: #if    (NENETFILTER > 256)
        !           182: #undef NENETFILTER
        !           183: #define        NENETFILTER     256             /* maximum number of minor devices */
        !           184: #endif
        !           185: 
        !           186: #define DEBUG  1
        !           187: /* #define INNERDEBUG 1 */     /* define only when debugging enDoFilter()
        !           188:                                        or enInputDone()  */
        !           189: 
        !           190: #define        enprintf(flags) if (enDebug&(flags)) printf
        !           191: 
        !           192: /*
        !           193:  * Symbolic definitions for enDebug flag bits
        !           194:  *     ENDBG_TRACE should be 1 because it is the most common
        !           195:  *     use in the code, and the compiler generates faster code
        !           196:  *     for testing the low bit in a word.
        !           197:  */
        !           198: 
        !           199: #define        ENDBG_TRACE     1       /* trace most operations */
        !           200: #define        ENDBG_DESQ      2       /* trace descriptor queues */
        !           201: #define        ENDBG_INIT      4       /* initialization info */
        !           202: #define        ENDBG_SCAV      8       /* scavenger operation */
        !           203: #define        ENDBG_ABNORM    16      /* abnormal events */
        !           204: 
        !           205: 
        !           206: #define min(a,b)        ( ((a)<=(b)) ? (a) : (b) )
        !           207: 
        !           208: #define        splenet splimp  /* used to be spl6 but I'm paranoid */
        !           209: 
        !           210: #define PRINET  26                     /* interruptible */
        !           211: 
        !           212: /*
        !           213:  *  'enQueueElts' is the pool of packet headers used by the driver.
        !           214:  *  'enPackets'   is the pool of packets used by the driver (these should
        !           215:  *               be allocated dynamically when this becomes possible).
        !           216:  *  'enFreeq'     is the queue of available packets
        !           217:  *  'enState'     is the driver state table per logical unit number
        !           218:  *  'enUnit'     is the physical unit number table per logical unit number;
        !           219:  *               the first "attach"ed ethernet is logical unit 0, etc.
        !           220:  *  'enUnitMap'          maps minor device numbers onto interface unit #s
        !           221:  *  'enAllocMap'  indicates if minor device is allocated or free
        !           222:  *  'enAllDescriptors' stores OpenDescriptors, indexed by minor device #
        !           223:  *  'enFreeqMin'  is the minimum number of packets ever in the free queue
        !           224:  *               (for statistics purposes)
        !           225:  *  'enScavenges' is the number of scavenges of the active input queues
        !           226:  *               (for statustics purposes)
        !           227:  *  'enDebug'    is a collection of debugging bits which enable trace and/or
        !           228:  *               diagnostic output as defined above (ENDBG_*)
        !           229:  *  'enUnits'    is the number of attached units
        !           230:  *  'enOneCopy'   if true, then no packet is delivered to more than one minor
        !           231:  *               device
        !           232:  */
        !           233: struct enPacket        enQueueElts[ENPACKETS];
        !           234: struct enQueue enFreeq;
        !           235: struct enState  enState[NENET];
        !           236: char           enUnitMap[NENETFILTER];
        !           237: char           enAllocMap[NENETFILTER];
        !           238: struct enOpenDescriptor
        !           239:                enAllDescriptors[NENETFILTER];
        !           240: int            enFreeqMin = ENPACKETS;
        !           241: int            enScavenges = 0;
        !           242: int            enDebug = ENDBG_ABNORM;
        !           243: int            enUnits = 0;
        !           244: int            enOneCopy = 0;
        !           245: int            enMaxMinors = NENETFILTER;
        !           246: 
        !           247: /*
        !           248:  *  Forward declarations for subroutines which return other
        !           249:  *  than integer types.
        !           250:  */
        !           251: extern boolean enDoFilter();
        !           252: 
        !           253: 
        !           254: /*
        !           255:  * Linkages to if_en.c
        !           256:  */
        !           257: 
        !           258: struct enet_info {
        !           259:        struct  ifnet *ifp;     /* which ifp for output */
        !           260: } enet_info[NENET];
        !           261: 
        !           262: struct sockaddr enetaf = { AF_IMPLINK };
        !           263: 
        !           264: 
        !           265: /****************************************************************
        !           266:  *                                                             *
        !           267:  *             Various Macros & Routines                       *
        !           268:  *                                                             *
        !           269:  ****************************************************************/
        !           270: 
        !           271: /*
        !           272:  *  forAllOpenDescriptors(p) -- a macro for iterating
        !           273:  *  over all currently open devices.  Use it in place of
        !           274:  *      "for ( ...; ... ; ... )"
        !           275:  *  and supply your own loop body.  The loop variable is the
        !           276:  *  parameter p which is set to point to the descriptor for
        !           277:  *  each open device in turn.
        !           278:  */
        !           279: 
        !           280: #define forAllOpenDescriptors(p)                                       \
        !           281:        for ((p) = (struct enOpenDescriptor *)enDesq.enQ_F;             \
        !           282:              (struct Queue *)(&enDesq) != &((p)->enOD_Link);           \
        !           283:              (p) = (struct enOpenDescriptor *)(p)->enOD_Link.F)
        !           284: 
        !           285: /*
        !           286:  *  enEnqueue - add an element to a queue
        !           287:  */
        !           288: 
        !           289: #define        enEnqueue(q, elt)                                               \
        !           290: {                                                                      \
        !           291:        enqueue((struct Queue *)(q), (struct Queue *)(elt));            \
        !           292:        (q)->enQ_NumQueued++;                                           \
        !           293: }
        !           294: 
        !           295: /*
        !           296:  *  enFlushQueue - release all packets from queue, freeing any
        !           297:  *  whose reference counts drop to 0.  Assumes caller
        !           298:  *  is at high IPL so that queue will not be modified while
        !           299:  *  it is being flushed.
        !           300:  */
        !           301: 
        !           302: enFlushQueue(q)
        !           303: register struct enQueue *q;
        !           304: {
        !           305: 
        !           306:     register struct enPacket *qelt;
        !           307: 
        !           308:     while((qelt=(struct enPacket *)dequeue((struct Queue *)q)) != NULL)
        !           309:     {
        !           310:        if (0 == --(qelt->enP_RefCount))
        !           311:        {
        !           312:            enEnqueue(&enFreeq, qelt);
        !           313:        }
        !           314:     }
        !           315:     q->enQ_NumQueued = 0;
        !           316: 
        !           317: }
        !           318: 
        !           319: /*
        !           320:  *  enInitWaitQueue - initialize an empty packet wait queue
        !           321:  */
        !           322: 
        !           323: enInitWaitQueue(wq)
        !           324: register struct enWaitQueue *wq;
        !           325: {                      
        !           326: 
        !           327:     wq->enWQ_Head = 0;
        !           328:     wq->enWQ_Tail = 0;
        !           329:     wq->enWQ_NumQueued = 0;
        !           330:     wq->enWQ_MaxWaiting = ENDEFWAITING;
        !           331: 
        !           332: }
        !           333: 
        !           334: /*
        !           335:  *  enEnWaitQueue - add a packet to a wait queue
        !           336:  */
        !           337: 
        !           338: enEnWaitQueue(wq, p)
        !           339: register struct enWaitQueue *wq;
        !           340: struct enPacket *p;
        !           341: {
        !           342: 
        !           343:     wq->enWQ_Packets[wq->enWQ_Tail] = p;
        !           344:     wq->enWQ_NumQueued++;
        !           345:     enNextWaitQueueIndex(wq->enWQ_Tail);
        !           346: 
        !           347: }
        !           348: 
        !           349: /*
        !           350:  *  enDeWaitQueue - remove a packet from a wait queue
        !           351:  */
        !           352: 
        !           353: struct enPacket *
        !           354: enDeWaitQueue(wq)
        !           355: register struct enWaitQueue *wq;
        !           356: {
        !           357: 
        !           358:     struct enPacket *p;
        !           359: 
        !           360:     wq->enWQ_NumQueued--;
        !           361:     if (wq->enWQ_NumQueued < 0)
        !           362:        panic("enDeWaitQueue"); 
        !           363:     p = wq->enWQ_Packets[wq->enWQ_Head];
        !           364:     enNextWaitQueueIndex(wq->enWQ_Head);
        !           365: 
        !           366:     return(p);
        !           367: 
        !           368: }
        !           369: 
        !           370: /*
        !           371:  *  enTrimWaitQueue - cut a wait queue back to size
        !           372:  */
        !           373: enTrimWaitQueue(wq, threshold)
        !           374: register struct enWaitQueue *wq;
        !           375: {
        !           376: 
        !           377:     register int Counter = (wq->enWQ_NumQueued - threshold);
        !           378:     register struct enPacket *p;
        !           379: 
        !           380: #ifdef DEBUG
        !           381:     enprintf(ENDBG_SCAV)
        !           382:                ("enTrimWaitQueue(%x, %d): %d\n", wq, threshold, Counter);
        !           383: #endif
        !           384:     while (Counter-- > 0)
        !           385:     {
        !           386:        wq->enWQ_NumQueued--;
        !           387:        enPrevWaitQueueIndex(wq->enWQ_Tail);
        !           388:        p = wq->enWQ_Packets[wq->enWQ_Tail];
        !           389:        if (0 == --(p->enP_RefCount))
        !           390:        {
        !           391:            m_freem(p->enP_mbuf);
        !           392:            enEnqueue(&enFreeq, p);
        !           393:        }
        !           394:     }
        !           395: }
        !           396: /*
        !           397:  *  enFlushWaitQueue - remove all packets from wait queue
        !           398:  */
        !           399: 
        !           400: #define        enFlushWaitQueue(wq)    enTrimWaitQueue(wq, 0)
        !           401: 
        !           402: /*
        !           403:  *  scavenging thresholds:
        !           404:  *
        !           405:  *  index by number of active files;  for N open files, each queue may retain
        !           406:  *  up to 1/Nth of the packets not guaranteed to be freed on scavenge.  The
        !           407:  *  total number of available packets is computed less one for sending.
        !           408:  *
        !           409:  *  (assumes high IPL)
        !           410:  */
        !           411: char enScavLevel[NENETFILTER+1];
        !           412: 
        !           413: /*
        !           414:  *  enInitScavenge -- set up ScavLevel table
        !           415:  */
        !           416: enInitScavenge()
        !           417: {
        !           418:     register int PoolSize = (ENPACKETS-ENMINSCAVENGE);
        !           419:     register int i = sizeof(enScavLevel);
        !           420: 
        !           421:     PoolSize--;                /* leave one for transmitter */
        !           422:     while (--i>0)
        !           423:         enScavLevel[i] = (PoolSize / i);
        !           424: }
        !           425: 
        !           426: /*
        !           427:  *  enScavenge -- scan all OpenDescriptors for all ethernets, releasing
        !           428:  *    any queued buffers beyond the prescribed limit and freeing any whose
        !           429:  *    refcounts drop to 0.
        !           430:  *    Assumes caller is at high IPL so that it is safe to modify the queues.
        !           431:  */
        !           432: enScavenge()
        !           433: {
        !           434: 
        !           435:     register struct enOpenDescriptor *d;
        !           436:     register int threshold = 0;
        !           437:     register struct enState *enStatep;
        !           438: 
        !           439:     for (enStatep=enState; enStatep < &enState[NENET]; enStatep++)
        !           440:        threshold += enCurOpens;
        !           441:     threshold = enScavLevel[threshold];
        !           442: 
        !           443:     /* recalculate thresholds based on current allocations */
        !           444:     enInitScavenge();
        !           445: 
        !           446:     enScavenges++;
        !           447: #ifdef DEBUG
        !           448:     enprintf(ENDBG_SCAV)("enScavenge: %d\n", threshold);
        !           449: #endif
        !           450:     for (enStatep=enState; enStatep < &enState[NENET]; enStatep++)
        !           451:     {
        !           452:        if (enDesq.enQ_F == 0)
        !           453:            continue;                   /* never initialized */
        !           454:        forAllOpenDescriptors(d)
        !           455:        {
        !           456:            enTrimWaitQueue(&(d->enOD_Waiting), threshold);
        !           457:        }
        !           458:     }
        !           459: 
        !           460: }
        !           461: 
        !           462: /*
        !           463:  *  enAllocatePacket - allocate the next packet from the free list
        !           464:  *
        !           465:  *  Assumes IPL is at high priority so that it is safe to touch the
        !           466:  *  packet queue.  If the queue is currently empty, scavenge for
        !           467:  *  more packets.
        !           468:  */
        !           469: 
        !           470: struct enPacket *
        !           471: enAllocatePacket()
        !           472: {
        !           473: 
        !           474:     register struct enPacket *p;
        !           475: 
        !           476:     if (0 == enFreeq.enQ_NumQueued)
        !           477:        enScavenge();
        !           478:     p = (struct enPacket *)dequeue((struct Queue *)&enFreeq);
        !           479:     if (p == NULL)
        !           480:        panic("enAllocatePacket");
        !           481:     if (enFreeqMin > --enFreeq.enQ_NumQueued)
        !           482:        enFreeqMin = enFreeq.enQ_NumQueued;
        !           483: 
        !           484:     p->enP_RefCount = 0;       /* just in case */
        !           485: 
        !           486:     return(p);
        !           487: 
        !           488: }
        !           489: 
        !           490: /*
        !           491:  *  enDeallocatePacket - place the packet back on the free packet queue
        !           492:  *
        !           493:  *  (High IPL assumed).
        !           494:  */
        !           495: 
        !           496: #define        enDeallocatePacket(p)                                           \
        !           497: {                                                                      \
        !           498:        if (p->enP_RefCount) panic("enDeallocatePacket: refcount != 0");\
        !           499:        enqueue((struct Queue *)&enFreeq, (struct Queue *)(p));         \
        !           500:        enFreeq.enQ_NumQueued++;                                        \
        !           501: }
        !           502: 
        !           503: /****************************************************************
        !           504:  *                                                             *
        !           505:  *         Routines to move uio data to/from mbufs             *
        !           506:  *                                                             *
        !           507:  ****************************************************************/
        !           508: 
        !           509: /*
        !           510:  * These two routines were inspired by/stolen from ../sys/uipc_socket.c
        !           511:  *        Both return error code (or 0 if success).
        !           512:  */
        !           513: 
        !           514: /*
        !           515:  * read: return contents of mbufs to user.  DO NOT free them, since
        !           516:  *     there may be multiple claims on the packet!
        !           517:  */
        !           518: enrmove(m, uio, count)
        !           519: register struct mbuf *m;
        !           520: register struct uio *uio;
        !           521: register int count;
        !           522: {
        !           523:        register int len;
        !           524:        register int error = 0;
        !           525:        
        !           526:        count = min(count, uio->uio_resid);     /* # of bytes to return */
        !           527:        
        !           528:        while ((count > 0) && m && (error == 0)) {
        !           529:            len = min(count, m->m_len); /* length of this transfer */
        !           530:            count -= len;
        !           531:            error = uiomove(mtod(m, caddr_t), (int)len, UIO_READ, uio);
        !           532:            
        !           533:            m = m->m_next;
        !           534:        }
        !           535:        return(error);
        !           536: }
        !           537: 
        !           538: enwmove(uio, mbufp)
        !           539: register struct uio *uio;
        !           540: register struct mbuf **mbufp;  /* top mbuf is returned by reference */
        !           541: {
        !           542:        struct mbuf *mtop = 0;
        !           543:        register struct mbuf *m;
        !           544:        register struct mbuf **mp = &mtop;
        !           545:        register struct iovec *iov;
        !           546:        register int len;
        !           547:        int error = 0;
        !           548:        
        !           549:        while ((uio->uio_resid > 0) && (error == 0)) {
        !           550:            iov = uio->uio_iov;
        !           551:            
        !           552:            if (iov->iov_len == 0) {
        !           553:                uio->uio_iov++;
        !           554:                uio->uio_iovcnt--;
        !           555:                if (uio->uio_iovcnt < 0)
        !           556:                    panic("enwmove: uio_iovcnt < 0 while uio_resid > 0");
        !           557:            }
        !           558:            MGET(m, M_WAIT, MT_DATA);
        !           559:            if (m == NULL) {
        !           560:                error = ENOBUFS;
        !           561:                break;
        !           562:            }
        !           563:            if (iov->iov_len >= CLBYTES) {      /* big enough to use a page */
        !           564:                register struct mbuf *p;
        !           565:                MCLGET(p, 1);
        !           566:                if (p == 0)
        !           567:                    goto nopages;
        !           568:                m->m_off = (int)p - (int)m;
        !           569:                len = CLBYTES;
        !           570:            }
        !           571:            else {
        !           572: nopages:
        !           573:                len = MIN(MLEN, iov->iov_len);
        !           574:            }
        !           575:            error = uiomove(mtod(m, caddr_t), len, UIO_WRITE, uio);
        !           576:            m->m_len = len;
        !           577:            *mp = m;
        !           578:            mp = &(m->m_next);
        !           579:        }
        !           580: 
        !           581:        if (error) {            /* probably uiomove fouled up */
        !           582:            if (mtop)
        !           583:                m_freem(mtop);
        !           584:        }
        !           585:        else {
        !           586:            *mbufp = mtop;      /* return ptr to top mbuf */
        !           587:        }
        !           588:        return(error);
        !           589: }
        !           590: 
        !           591: /*
        !           592:  *  enetopen - open ether net device
        !           593:  *
        !           594:  *  Errors:    ENXIO   - illegal minor device number
        !           595:  *             EBUSY   - minor device already in use
        !           596:  */
        !           597: 
        !           598: /* ARGSUSED */
        !           599: enetopen(dev, flag, newmin)
        !           600: dev_t dev;
        !           601: int flag;
        !           602: int *newmin;
        !           603: {
        !           604:     register int md;
        !           605:     register int unit = minor(dev);
        !           606:     register struct enState *enStatep;
        !           607: #ifndef        SUN_OPENI
        !           608:     register int error;
        !           609: #endif SUN_OPENI
        !           610: 
        !           611:     /*
        !           612:      * Each open enet file has a different minor device number.
        !           613:      * When a user tries to open any of them, we actually open
        !           614:      * any available minor device and associate it with the
        !           615:      * corresponding unit.
        !           616:      *
        !           617:      * This is not elegant, but UNIX will call
        !           618:      * open for each new open file using the same inode but calls
        !           619:      * close only when the last open file referring to the inode 
        !           620:      * is released. This means that we cannot know inside the
        !           621:      * driver code when the resources associated with a particular
        !           622:      * open of the same inode should be deallocated.  Thus, we have
        !           623:      * to make up a temporary inode to represent each simultaneous
        !           624:      * open of the ethernet.  Each inode has a different minor device number.
        !           625:      */
        !           626: 
        !           627: #ifdef DEBUG
        !           628:     enprintf(ENDBG_TRACE)("enetopen(%o, %x):\n", unit, flag);
        !           629: #endif
        !           630: 
        !           631:     /* check for illegal minor dev */
        !           632:     if ( (unit >= enUnits)                             /* bad unit */
        !           633:         || (enet_info[unit].ifp == 0)                  /* ifp not known */
        !           634:        || ((enet_info[unit].ifp->if_flags & IFF_UP) == 0) )
        !           635:                                                        /* or if down */
        !           636:     {
        !           637:        return(ENXIO);
        !           638:     }
        !           639: 
        !           640:     md = enFindMinor();
        !           641: #ifdef DEBUG
        !           642:     enprintf(ENDBG_TRACE)("enetopen: md = %d\n", md);
        !           643: #endif
        !           644:     if (md < 0)
        !           645:     {
        !           646:        return(EBUSY);
        !           647:     }
        !           648: 
        !           649:     enUnitMap[md] = unit;
        !           650:     enAllocMap[md] = TRUE;
        !           651: 
        !           652: #ifdef SUN_OPENI
        !           653:     *newmin = md;
        !           654: #else
        !           655:     error = mkpseudo(makedev(major(dev), md)));
        !           656:     if (error) {
        !           657:        enAllocMap[md] = FALSE;
        !           658:        return(error);
        !           659:     }
        !           660: #endif SUN_OPENI
        !           661: 
        !           662:     enStatep = &enState[unit];
        !           663:     enprintf(ENDBG_DESQ)
        !           664:        ("enetopen: Desq: %x, %x\n", enDesq.enQ_F, enDesq.enQ_B);
        !           665:     enInitDescriptor(&enAllDescriptors[md], flag);
        !           666:     enInsertDescriptor(&(enDesq), &enAllDescriptors[md]);
        !           667: 
        !           668:     return(0);
        !           669: }
        !           670: 
        !           671: /*
        !           672:  * enFindMinor - find a free logical device on specified unit
        !           673:  */
        !           674: enFindMinor()
        !           675: {
        !           676:        register int md;
        !           677:        
        !           678:        for (md = 0; md < enMaxMinors; md++) {
        !           679:                if (enAllocMap[md] == FALSE)
        !           680:                        return(md);
        !           681:        }
        !           682:        return(-1);
        !           683: }
        !           684: 
        !           685: /*
        !           686:  *  enInit - intialize ethernet unit (called by enetattach)
        !           687:  */
        !           688: 
        !           689: enInit(enStatep, unit)
        !           690: register struct enState *enStatep;
        !           691: register int unit;
        !           692: {
        !           693: 
        !           694: #ifdef DEBUG
        !           695:     enprintf(ENDBG_INIT)("enInit(%x %d):\n", enStatep, unit);
        !           696: #endif
        !           697: 
        !           698:     /*  initialize free queue if not already done  */
        !           699:     if (enFreeq.enQ_F == 0)
        !           700:     {
        !           701:        register int i;
        !           702: 
        !           703:        initqueue((struct Queue *)&enFreeq);
        !           704:        for (i=0; i<ENPACKETS; i++)
        !           705:        {
        !           706:            register struct enPacket *p;
        !           707: 
        !           708:            p = &enQueueElts[i];
        !           709:            p->enP_RefCount = 0;
        !           710:            enDeallocatePacket(p);
        !           711:        }
        !           712:        /* also a good time to init enAllocMap */
        !           713:        for (i = 0; i < enMaxMinors; i++)
        !           714:                enAllocMap[i] = FALSE;
        !           715:     }
        !           716:     initqueue((struct Queue *)&enDesq);        /* init descriptor queue */
        !           717: }        
        !           718: 
        !           719: /*
        !           720:  *  enetclose - ether net device close routine
        !           721:  */
        !           722: 
        !           723: /* ARGSUSED */
        !           724: enetclose(dev, flag)
        !           725: {
        !           726:     register int md = ENINDEX(dev);
        !           727:     register struct enState *enStatep = &enState[ENUNIT(dev)];
        !           728:     register struct enOpenDescriptor *d = &enAllDescriptors[md];
        !           729:     int ipl;
        !           730: 
        !           731:     enAllocMap[md] = FALSE;
        !           732: 
        !           733: #ifdef DEBUG
        !           734:     enprintf(ENDBG_TRACE)("enetclose(%d, %x):\n", md, flag);
        !           735: #endif
        !           736: 
        !           737:     /*
        !           738:      *  insure that receiver doesn't try to queue something
        !           739:      *  for the device as we are decommissioning it.
        !           740:      *  (I don't think this is necessary, but I'm a coward.)
        !           741:      */
        !           742:     ipl = splenet();
        !           743:     dequeue((struct Queue *)d->enOD_Link.B);
        !           744:     enCurOpens--;
        !           745:     enprintf(ENDBG_DESQ)
        !           746:                ("enetclose: Desq: %x, %x\n", enDesq.enQ_F, enDesq.enQ_B);
        !           747:     enFlushWaitQueue(&(d->enOD_Waiting));
        !           748:     splx(ipl);
        !           749: 
        !           750: }
        !           751: 
        !           752: /*
        !           753:  *  enetread - read next packet from net
        !           754:  */
        !           755: 
        !           756: /* VARARGS */
        !           757: enetread(dev, uio)
        !           758: dev_t dev;
        !           759: register struct uio *uio;
        !           760: {
        !           761:     register struct enOpenDescriptor *d = &enAllDescriptors[ENINDEX(dev)];
        !           762:     register struct enPacket *p;
        !           763:     int ipl;
        !           764:     int error;
        !           765:     extern enTimeout();
        !           766: 
        !           767: #if    DEBUG
        !           768:     enprintf(ENDBG_TRACE)("enetread(%x):", dev);
        !           769: #endif
        !           770: 
        !           771:     ipl = splenet();
        !           772:     /*
        !           773:      *  If nothing is on the queue of packets waiting for
        !           774:      *  this open enet file, then set timer and sleep until
        !           775:      *  either the timeout has occurred or a packet has
        !           776:      *  arrived.
        !           777:      */
        !           778: 
        !           779:     while (0 == d->enOD_Waiting.enWQ_NumQueued)
        !           780:     {
        !           781:        if (d->enOD_Timeout < 0)
        !           782:        {
        !           783:            splx(ipl);
        !           784:            return(0);
        !           785:        }
        !           786:         if (d->enOD_Timeout)
        !           787:        {
        !           788:            /*
        !           789:             *  If there was a previous timeout pending for this file,
        !           790:             *  cancel it before setting another.  This is necessary since
        !           791:             *  a cancel after the sleep might never happen if the read is
        !           792:             *  interrupted by a signal.
        !           793:             */
        !           794:            if (d->enOD_RecvState == ENRECVTIMING)
        !           795:                untimeout(enTimeout, (caddr_t)d);
        !           796:             timeout(enTimeout, (caddr_t)d, (int)(d->enOD_Timeout));
        !           797:             d->enOD_RecvState = ENRECVTIMING;
        !           798:        }
        !           799:         else
        !           800:             d->enOD_RecvState = ENRECVIDLE;
        !           801: 
        !           802:         sleep((caddr_t)d, PRINET);
        !           803: 
        !           804:         switch (d->enOD_RecvState)
        !           805:        {
        !           806:             case ENRECVTIMING:
        !           807:            {
        !           808:                 untimeout(enTimeout, (caddr_t)d);
        !           809:                 d->enOD_RecvState = ENRECVIDLE;
        !           810:                break;
        !           811:            }
        !           812:             case ENRECVTIMEDOUT:
        !           813:            {
        !           814:                 splx(ipl);
        !           815:                return(0);
        !           816:            }
        !           817:        }
        !           818:     }
        !           819: 
        !           820:     p = enDeWaitQueue(&(d->enOD_Waiting));
        !           821:     splx(ipl);
        !           822: 
        !           823:     /*  
        !           824:      * Move data from packet into user space.
        !           825:      */
        !           826:     error = enrmove(p->enP_mbuf, uio, p->enP_ByteCount);
        !           827: 
        !           828:     ipl = splenet();
        !           829:     if (0 == --(p->enP_RefCount))      /* if no more claims on this packet */
        !           830:     {
        !           831:        m_freem(p->enP_mbuf);   /* release mbuf */
        !           832:        enDeallocatePacket(p);  /* and packet */
        !           833:     }
        !           834:     splx(ipl);
        !           835: 
        !           836:     return(error);
        !           837: }
        !           838: 
        !           839: 
        !           840: 
        !           841: /*
        !           842:  *  enTimeout - process ethernet read timeout
        !           843:  */
        !           844: 
        !           845: enTimeout(d)
        !           846: register struct enOpenDescriptor * d;
        !           847: {
        !           848:     register int ipl;
        !           849: 
        !           850: #ifdef DEBUG
        !           851:     enprintf(ENDBG_TRACE)("enTimeout(%x):\n", d);
        !           852: #endif
        !           853:     ipl = splenet();
        !           854:     d->enOD_RecvState = ENRECVTIMEDOUT;
        !           855:     wakeup((caddr_t)d);
        !           856:     enetwakeup(d);
        !           857:     splx(ipl);
        !           858: 
        !           859: }
        !           860: 
        !           861: /*
        !           862:  *  enetwrite - write next packet to net
        !           863:  */
        !           864: 
        !           865: int enKludgeSleep[NENET];      /* Are we sleeping on IF_QFULL? */
        !           866:                                /*  really, # of procs sleeping on IF_QFULL */
        !           867: 
        !           868: /* VARARGS */
        !           869: enetwrite(dev, uio)
        !           870: dev_t dev;
        !           871: register struct uio *uio;
        !           872: {
        !           873:     register int unit = ENUNIT(dev);
        !           874:     register struct enState *enStatep = &enState[unit];
        !           875:     struct mbuf *mp;
        !           876:     register struct ifnet *ifp = enet_info[unit].ifp;
        !           877:     int ipl;
        !           878:     int error;
        !           879:     int sleepcount;
        !           880:     int enKludgeTime();
        !           881: 
        !           882: #if    DEBUG
        !           883:     enprintf(ENDBG_TRACE)("enetwrite(%x):\n", dev);
        !           884: #endif
        !           885: 
        !           886:      if (uio->uio_resid == 0)
        !           887:         return(0);
        !           888:      if (uio->uio_resid > ifp->if_mtu) /* too large */
        !           889:         return(EMSGSIZE);
        !           890:  
        !           891:     /*
        !           892:      * Copy user data into mbufs
        !           893:      */
        !           894:      if (error = enwmove(uio, &mp)) {
        !           895:         return(error);
        !           896:      }
        !           897: 
        !           898:     ipl = splenet();
        !           899:     /*
        !           900:      * if the queue is full,
        !           901:      * hang around until there's room or until process is interrupted
        !           902:      */
        !           903:     sleepcount = 0;
        !           904:     while (IF_QFULL(&(ifp->if_snd))) {
        !           905:        extern int hz;
        !           906:        if (sleepcount++ > 2) { /* don't sleep too long */
        !           907:            splx(ipl);
        !           908:            return(ETIMEDOUT);
        !           909:        }
        !           910:        /* if nobody else has a timeout pending for this unit, set one */
        !           911:        if (enKludgeSleep[unit] == 0)
        !           912:            timeout(enKludgeTime, (caddr_t)unit, 2 * hz);
        !           913:        enKludgeSleep[unit]++;  /* record that we are sleeping */
        !           914:        if (setjmp(&u.u_qsave)) {
        !           915:            /* sleep (following) was interrupted, clean up */
        !           916: #if    DEBUG
        !           917:            enprintf(ENDBG_ABNORM)
        !           918:                ("enetwrite(%x): enet%d sleep %d interrupted\n", dev,
        !           919:                        unit, enKludgeSleep[unit]);
        !           920: #endif DEBUG
        !           921:            enKludgeSleep[unit]--;      /* we're no longer sleeping */
        !           922:            m_freem(mp);
        !           923:            splx(ipl);
        !           924:            return(EINTR);
        !           925:        }
        !           926:        sleep((caddr_t)&(enKludgeSleep[unit]), PRINET);
        !           927:        enKludgeSleep[unit]--;  /* we are no longer sleeping */
        !           928:     }
        !           929:     
        !           930:     /* place mbuf chain on outgoing queue & start if necessary */
        !           931:     error = (*ifp->if_output)(ifp, mp, &enetaf);
        !           932:                        /* this always frees the mbuf chain */
        !           933:     enXcnt++;
        !           934:     
        !           935:     splx(ipl);
        !           936:     
        !           937:     return(error);
        !           938: }
        !           939: 
        !           940: enKludgeTime(unit)
        !           941: int unit;
        !           942: {
        !           943:        /* XXX perhaps we should always wakeup? */
        !           944:        if (enKludgeSleep[unit]) {
        !           945:                wakeup((caddr_t)&(enKludgeSleep[unit]));
        !           946:                /* XXX should we restart transmitter? */
        !           947:        }
        !           948: }
        !           949: 
        !           950: /*
        !           951:  *  enetioctl - ether net control
        !           952:  *
        !           953:  *  EIOCGETP    - get ethernet parameters
        !           954:  *  EIOCSETP    - set ethernet read timeout
        !           955:  *  EIOCSETF    - set ethernet read filter
        !           956:  *  EIOCENBS    - enable signal when read packet available
        !           957:  *  EIOCINHS     - inhibit signal when read packet available
        !           958:  *  FIONREAD    - check for read packet available
        !           959:  *  EIOCSETW    - set maximum read packet waiting queue length
        !           960:  *  EIOCFLUSH   - flush read packet waiting queue
        !           961:  *  EIOCMBIS    - set mode bits
        !           962:  *  EIOCMBIC    - clear mode bits
        !           963:  *  EICODEVP    - get device parameters
        !           964:  *  EIOCMFREE   - number of free minors
        !           965:  */
        !           966: 
        !           967: /* ARGSUSED */
        !           968: enetioctl(dev, cmd, addr, flag)
        !           969: caddr_t addr;
        !           970: dev_t flag;
        !           971: {
        !           972: 
        !           973:     register struct enState *enStatep = &enState[ENUNIT(dev)];
        !           974:     register struct enOpenDescriptor * d = &enAllDescriptors[ENINDEX(dev)];
        !           975:     int ipl;
        !           976: 
        !           977: #if    DEBUG
        !           978:     enprintf(ENDBG_TRACE)
        !           979:                ("enetioctl(%x, %x, %x, %x):\n", dev, cmd, addr, flag);
        !           980: #endif
        !           981: 
        !           982:     switch (cmd)
        !           983:     {
        !           984:        case EIOCGETP:
        !           985:        {
        !           986:             struct eniocb t;
        !           987: 
        !           988:            t.en_maxwaiting = ENMAXWAITING;
        !           989:            t.en_maxpriority = ENMAXPRI;
        !           990:             t.en_rtout = d->enOD_Timeout;
        !           991:            t.en_addr = -1;
        !           992:            t.en_maxfilters = ENMAXFILTERS;
        !           993: 
        !           994:            bcopy((caddr_t)&t, addr, sizeof t);
        !           995:        }
        !           996:         endcase
        !           997: 
        !           998:         case EIOCSETP:
        !           999:        {
        !          1000:             struct eniocb t;
        !          1001: 
        !          1002:             bcopy(addr, (caddr_t)&t, sizeof t);
        !          1003:             d->enOD_Timeout = t.en_rtout;
        !          1004:        }
        !          1005:         endcase
        !          1006: 
        !          1007:         case EIOCSETF:
        !          1008:        {
        !          1009:             struct enfilter f;
        !          1010:            unsigned short *fp;
        !          1011: 
        !          1012:             bcopy(addr, (caddr_t)&f, sizeof f);
        !          1013:            if (f.enf_FilterLen > ENMAXFILTERS)
        !          1014:            {
        !          1015:                return(EINVAL);
        !          1016:            }
        !          1017:             /* insure that filter is installed indivisibly */
        !          1018:             ipl = splenet();
        !          1019:             bcopy((caddr_t)&f, (caddr_t)&(d->enOD_OpenFilter), sizeof f);
        !          1020:            /* pre-compute length of filter */
        !          1021:            fp = &(d->enOD_OpenFilter.enf_Filter[0]);
        !          1022:            d->enOD_FiltEnd = &(fp[d->enOD_OpenFilter.enf_FilterLen]);
        !          1023:            d->enOD_RecvCount = 0;      /* reset count when filter changes */
        !          1024:            dequeue((struct Queue *)d->enOD_Link.B);
        !          1025:            enDesq.enQ_NumQueued--;
        !          1026:            enInsertDescriptor(&(enDesq), d);
        !          1027:             splx(ipl);
        !          1028:        }
        !          1029:         endcase
        !          1030: 
        !          1031:        /*
        !          1032:         *  Enable signal n on input packet
        !          1033:         */
        !          1034:        case EIOCENBS:
        !          1035:        {
        !          1036:             int snum;
        !          1037: 
        !          1038:            bcopy(addr, (caddr_t)&snum, sizeof snum);
        !          1039:            if (snum < NSIG) {
        !          1040:                    d->enOD_SigProc = u.u_procp;
        !          1041:                    d->enOD_SigPid  = u.u_procp->p_pid;
        !          1042:                    d->enOD_SigNumb = snum;     /* This must be set last */
        !          1043:            } else {
        !          1044:                    goto bad;
        !          1045:            }
        !          1046:        }
        !          1047:        endcase
        !          1048: 
        !          1049:        /*
        !          1050:         *  Disable signal on input packet
        !          1051:         */
        !          1052:        case EIOCINHS:
        !          1053:        {
        !          1054:                d->enOD_SigNumb = 0;
        !          1055:        }
        !          1056:        endcase
        !          1057: 
        !          1058:        /*
        !          1059:         *  Check for packet waiting
        !          1060:         */
        !          1061:        case FIONREAD:
        !          1062:        {
        !          1063:             int n;
        !          1064:             register struct enWaitQueue *wq;
        !          1065: 
        !          1066:            ipl = splenet();
        !          1067:            if ((wq = &(d->enOD_Waiting))->enWQ_NumQueued)
        !          1068:                n = wq->enWQ_Packets[wq->enWQ_Head]->enP_ByteCount;
        !          1069:            else
        !          1070:                n = 0;
        !          1071:            splx(ipl);
        !          1072:            bcopy((caddr_t)&n, addr, sizeof n);
        !          1073:        }
        !          1074:        endcase
        !          1075: 
        !          1076:        /*
        !          1077:         *  Set maximum recv queue length for a device
        !          1078:         */
        !          1079:        case EIOCSETW:
        !          1080:        {
        !          1081:             unsigned un;
        !          1082: 
        !          1083:            bcopy(addr, (caddr_t)&un, sizeof un);
        !          1084:            /*
        !          1085:              *  unsigned un         MaxQueued
        !          1086:              * ----------------    ------------
        !          1087:              *  0               ->  DEFWAITING
        !          1088:             *  1..MAXWAITING   ->  un
        !          1089:             *  MAXWAITING..-1  ->  MAXWAITING
        !          1090:              */
        !          1091:            d->enOD_Waiting.enWQ_MaxWaiting = (un) ? min(un, ENMAXWAITING)
        !          1092:                                         : ENDEFWAITING;
        !          1093:        }
        !          1094:        endcase
        !          1095: 
        !          1096:        /*
        !          1097:         *  Flush all packets queued for a device
        !          1098:         */
        !          1099:        case EIOCFLUSH:
        !          1100:        {
        !          1101:            ipl = splenet();
        !          1102:            enFlushWaitQueue(&(d->enOD_Waiting));
        !          1103:            splx(ipl);
        !          1104:        }
        !          1105:        endcase
        !          1106: 
        !          1107:        /*
        !          1108:         *  Set mode bits
        !          1109:         */
        !          1110:        case EIOCMBIS:
        !          1111:        {
        !          1112:            u_short mode;
        !          1113: 
        !          1114:            bcopy(addr, (caddr_t)&mode, sizeof mode);
        !          1115:            if (mode&ENPRIVMODES)
        !          1116:                return(EINVAL);
        !          1117:            else
        !          1118:                d->enOD_Flag |= mode;
        !          1119:        }
        !          1120:        endcase
        !          1121: 
        !          1122:        /*
        !          1123:         *  Clear mode bits
        !          1124:         */
        !          1125:        case EIOCMBIC:
        !          1126:        {
        !          1127:            u_short mode;
        !          1128: 
        !          1129:            bcopy(addr, (caddr_t)&mode, sizeof mode);
        !          1130:            if (mode&ENPRIVMODES)
        !          1131:                return(EINVAL);
        !          1132:            else
        !          1133:                d->enOD_Flag &= ~mode;
        !          1134:        }
        !          1135:        endcase
        !          1136: 
        !          1137:        /*
        !          1138:         * Return hardware-specific device parameters.
        !          1139:         */
        !          1140:        case EIOCDEVP:
        !          1141:        {
        !          1142:            bcopy((caddr_t)&(enDevParams), addr, sizeof(struct endevp));
        !          1143:        }
        !          1144:        endcase;
        !          1145: 
        !          1146:        /*
        !          1147:         * Return # of free minor devices.
        !          1148:         */
        !          1149:        case EIOCMFREE:
        !          1150:        {
        !          1151:            register int md;
        !          1152:            register int sum = 0;
        !          1153:            
        !          1154:            for (md = 0; md < enMaxMinors; md++)
        !          1155:                if (enAllocMap[md] == FALSE)
        !          1156:                        sum++;
        !          1157:            *(int *)addr = sum;
        !          1158:        }
        !          1159:        endcase;
        !          1160: 
        !          1161:         default:
        !          1162:        {
        !          1163:        bad:
        !          1164:            return(EINVAL);
        !          1165:        }
        !          1166:     }
        !          1167: 
        !          1168:     return(0);
        !          1169: 
        !          1170: }
        !          1171:                               
        !          1172: /****************************************************************
        !          1173:  *                                                             *
        !          1174:  *             Support for select() system call                *
        !          1175:  *                                                             *
        !          1176:  *     Other hooks in:                                         *
        !          1177:  *             enInitDescriptor()                              *
        !          1178:  *             enInputDone()                                   *
        !          1179:  *             enTimeout()                                     *
        !          1180:  ****************************************************************/
        !          1181: /*
        !          1182:  * inspired by the code in tty.c for the same purpose.
        !          1183:  */
        !          1184: 
        !          1185: /*
        !          1186:  * enetselect - returns true iff the specific operation
        !          1187:  *     will not block indefinitely.  Otherwise, return
        !          1188:  *     false but make a note that a selwakeup() must be done.
        !          1189:  */
        !          1190: enetselect(dev, rw)
        !          1191: register dev_t dev;
        !          1192: int rw;
        !          1193: {
        !          1194:        register struct enOpenDescriptor *d;
        !          1195:        register struct enWaitQueue *wq;
        !          1196:        register int ipl;
        !          1197:        register int avail;
        !          1198:        
        !          1199:        switch (rw) {
        !          1200:        
        !          1201:        case FREAD:
        !          1202:                /*
        !          1203:                 * an imitation of the FIONREAD ioctl code
        !          1204:                 */
        !          1205:                d = &(enAllDescriptors[ENINDEX(dev)]);
        !          1206:                
        !          1207:                ipl = splenet();
        !          1208:                wq = &(d->enOD_Waiting);
        !          1209:                if (wq->enWQ_NumQueued)
        !          1210:                        avail = 1;      /* at least one packet queued */
        !          1211:                else {
        !          1212:                        avail = 0;      /* sorry, nothing queued now */
        !          1213:                        /*
        !          1214:                         * If there's already a select() waiting on this
        !          1215:                         * minor device then this is a collision.
        !          1216:                         * [This shouldn't happen because enet minors
        !          1217:                         * really should not be shared, but if a process
        !          1218:                         * forks while one of these is open, it is possible
        !          1219:                         * that both processes could select() us.]
        !          1220:                         */
        !          1221:                        if (d->enOD_SelProc
        !          1222:                             && d->enOD_SelProc->p_wchan == (caddr_t)&selwait)
        !          1223:                                d->enOD_SelColl = 1;
        !          1224:                        else
        !          1225:                                d->enOD_SelProc = u.u_procp;            
        !          1226:                }
        !          1227:                splx(ipl);      
        !          1228:                return(avail);
        !          1229: 
        !          1230:        case FWRITE:
        !          1231:                /*
        !          1232:                 * since the queueing for output is shared not just with
        !          1233:                 * the other enet devices but also with the IP system,
        !          1234:                 * we can't predict what would happen on a subsequent
        !          1235:                 * write.  However, since we presume that all writes
        !          1236:                 * complete eventually, and probably fairly fast, we
        !          1237:                 * pretend that select() is true.
        !          1238:                 */
        !          1239:                return(1);
        !          1240: 
        !          1241:        default:                /* hmmm. */
        !          1242:                return(1);              /* don't block in select() */
        !          1243:        }
        !          1244: }
        !          1245: 
        !          1246: enetwakeup(d)
        !          1247: register struct enOpenDescriptor *d;
        !          1248: {
        !          1249:        if (d->enOD_SelProc) {
        !          1250:                selwakeup(d->enOD_SelProc, d->enOD_SelColl);
        !          1251:                d->enOD_SelColl = 0;
        !          1252:                d->enOD_SelProc = 0;
        !          1253:        }
        !          1254: }
        !          1255: 
        !          1256: /*
        !          1257:  * enetFilter - incoming linkage from ../vaxif/if_en.c
        !          1258:  */
        !          1259: 
        !          1260: enetFilter(en, m, count)
        !          1261: register int en;
        !          1262: register struct mbuf *m;
        !          1263: register int count;
        !          1264: {
        !          1265:     register struct enState *enStatep = &enState[en];
        !          1266:     register struct enPacket *p;
        !          1267:     register int pullcount;    /* bytes, not words */
        !          1268:     int s = splenet();
        !          1269: 
        !          1270: #if    DEBUG
        !          1271:     enprintf(ENDBG_TRACE)("enetFilter(%d):\n", en);
        !          1272: #endif
        !          1273: 
        !          1274:     p = enAllocatePacket();    /* panics if not possible */
        !          1275: 
        !          1276:     p->enP_ByteCount = count;
        !          1277:     
        !          1278:     pullcount = min(MLEN, count);      /* largest possible first mbuf */
        !          1279:     if (m->m_len < pullcount) {
        !          1280:        /* first mbuf not as full as it could be - fix this */
        !          1281:        if ((m = m_pullup(m, pullcount)) == 0) {
        !          1282:            /* evidently no resources; bloody m_pullup discarded mbuf */
        !          1283:            enDeallocatePacket(p);
        !          1284:            enRdrops++;
        !          1285:            goto out;
        !          1286:        }
        !          1287:     }
        !          1288:     
        !          1289:     p->enP_mbuf = m;
        !          1290:     p->enP_Data = mtod(m, u_short *);
        !          1291: 
        !          1292:     enInputDone(enStatep, p);
        !          1293: out:
        !          1294:     splx(s);
        !          1295: }
        !          1296: 
        !          1297: /*
        !          1298:  * enInputDone - process correctly received packet
        !          1299:  */
        !          1300: 
        !          1301: enInputDone(enStatep, p)
        !          1302: register struct enState *enStatep;
        !          1303: register struct enPacket *p;
        !          1304: {
        !          1305:     register struct enOpenDescriptor *d;
        !          1306:     int queued = 0;
        !          1307:     register int maxword;
        !          1308:     register unsigned long rcount;
        !          1309:     register struct enOpenDescriptor *prevd;
        !          1310: 
        !          1311: #if    INNERDEBUG
        !          1312:     enprintf(ENDBG_TRACE)("enInputDone(%x): %x\n", enStatep, p);
        !          1313: #endif
        !          1314:     /* precompute highest possible word offset */
        !          1315:     /* can't address beyond end of packet or end of first mbuf */
        !          1316:     maxword = (min(p->enP_ByteCount, p->enP_mbuf->m_len)>>1);
        !          1317: 
        !          1318:     forAllOpenDescriptors(d)
        !          1319:     {
        !          1320:        if (enDoFilter(p, d, maxword))
        !          1321:        {
        !          1322:             if (d->enOD_Waiting.enWQ_NumQueued < d->enOD_Waiting.enWQ_MaxWaiting)
        !          1323:            {
        !          1324:                 enEnWaitQueue(&(d->enOD_Waiting), p);
        !          1325:                 p->enP_RefCount++;
        !          1326:                queued++;
        !          1327:                 wakeup((caddr_t)d);
        !          1328:                enetwakeup(d);
        !          1329: #if    INNERDEBUG
        !          1330:                 enprintf(ENDBG_TRACE)("enInputDone: queued\n");
        !          1331: #endif
        !          1332:            }
        !          1333:            /*  send notification when input packet received  */
        !          1334:            if (d->enOD_SigNumb) {
        !          1335:                if (d->enOD_SigProc->p_pid == d->enOD_SigPid)
        !          1336:                        psignal(d->enOD_SigProc, d->enOD_SigNumb);
        !          1337:                if ((d->enOD_Flag & ENHOLDSIG) == 0)
        !          1338:                        d->enOD_SigNumb = 0;            /* disable signal */
        !          1339:            }
        !          1340:            rcount = ++(d->enOD_RecvCount);
        !          1341:            
        !          1342:            /* see if ordering of filters is wrong */
        !          1343:            if (d->enOD_OpenFilter.enf_Priority >= ENHIPRI) {
        !          1344:                prevd = (struct enOpenDescriptor *)d->enOD_Link.B;
        !          1345:                /*
        !          1346:                 * If d is not the first element on the queue, and
        !          1347:                 * the previous element is at equal priority but has
        !          1348:                 * a lower count, then promote d to be in front of prevd.
        !          1349:                 */
        !          1350:                if (((struct Queue *)prevd != &(enDesq.enQ_Head)) &&
        !          1351:                    (d->enOD_OpenFilter.enf_Priority ==
        !          1352:                                prevd->enOD_OpenFilter.enf_Priority)) {
        !          1353:                    /* threshold difference to avoid thrashing */
        !          1354:                    if ((100 + prevd->enOD_RecvCount) < rcount) {
        !          1355:                        enReorderQueue(&(prevd->enOD_Link), &(d->enOD_Link));
        !          1356:                    }
        !          1357:                }
        !          1358:                break;  /* high-priority filter => no more deliveries */
        !          1359:            }
        !          1360:            else if (enOneCopy)
        !          1361:                break;
        !          1362:        }
        !          1363:     }
        !          1364:     if (queued == 0)                   /* this buffer no longer in use */
        !          1365:     {
        !          1366:        m_freem(p->enP_mbuf);                   /* free mbuf */
        !          1367:        enDeallocatePacket(p);                  /*  and packet */
        !          1368:        enRdrops++;
        !          1369:     }
        !          1370:     else
        !          1371:        enRcnt++;
        !          1372: 
        !          1373: }
        !          1374: 
        !          1375: #define        opx(i)  (i>>ENF_NBPA)
        !          1376: 
        !          1377: boolean
        !          1378: enDoFilter(p, d, maxword)
        !          1379: struct enPacket *p;
        !          1380: struct enOpenDescriptor *d;
        !          1381: register int maxword;
        !          1382: {
        !          1383: 
        !          1384:     register unsigned short *sp;
        !          1385:     register unsigned short *fp;
        !          1386:     register unsigned short *fpe;
        !          1387:     register unsigned op;
        !          1388:     register unsigned arg;
        !          1389:     unsigned short stack[ENMAXFILTERS+1];
        !          1390:     struct fw {unsigned arg:ENF_NBPA, op:ENF_NBPO;};
        !          1391: 
        !          1392: #ifdef INNERDEBUG
        !          1393:     enprintf(ENDBG_TRACE)("enDoFilter(%x,%x):\n", p, d);
        !          1394: #endif
        !          1395:     sp = &stack[ENMAXFILTERS];
        !          1396:     fp = &d->enOD_OpenFilter.enf_Filter[0];
        !          1397:     fpe = d->enOD_FiltEnd;
        !          1398:        /* ^ is really: fpe = &fp[d->enOD_OpenFilter.enf_FilterLen]; */
        !          1399:     *sp = TRUE;
        !          1400: 
        !          1401:     for (; fp < fpe; )
        !          1402:     {
        !          1403:        op = ((struct fw *)fp)->op;
        !          1404:        arg = ((struct fw *)fp)->arg;
        !          1405:        fp++;
        !          1406:        switch (arg)
        !          1407:        {
        !          1408:            default:
        !          1409:                arg -= ENF_PUSHWORD;
        !          1410: #ifndef        lint
        !          1411:                /*
        !          1412:                 * This next test is a little bogus; since arg
        !          1413:                 * is unsigned, it is always >= 0 (the compiler
        !          1414:                 * knows this and emits no code).  If arg were
        !          1415:                 * less than ENF_PUSHWORD before the subtract,
        !          1416:                 * it is certaintly going to be more than maxword
        !          1417:                 * afterward, so the code does work "right"
        !          1418:                 */
        !          1419:                if ((arg >= 0) && (arg < maxword))
        !          1420: #else
        !          1421:                if (arg < maxword)
        !          1422: #endif lint
        !          1423:                    *--sp = p->enP_Data[arg];
        !          1424:                else
        !          1425:                {
        !          1426: #ifdef INNERDEBUG
        !          1427:                    enprintf(ENDBG_TRACE)("=>0(len)\n");
        !          1428: #endif
        !          1429:                    return(false);
        !          1430:                }
        !          1431:                break;
        !          1432:            case ENF_PUSHLIT:
        !          1433:                *--sp = *fp++;
        !          1434:                break;
        !          1435:            case ENF_PUSHZERO:
        !          1436:                *--sp = 0;
        !          1437:            case ENF_NOPUSH:
        !          1438:                break;
        !          1439:        }
        !          1440:        if (sp < &stack[2])     /* check stack overflow: small yellow zone */
        !          1441:        {
        !          1442:            enprintf(ENDBG_TRACE)("=>0(--sp)\n");
        !          1443:            return(false);
        !          1444:        }
        !          1445:        if (op == ENF_NOP)
        !          1446:            continue;
        !          1447:        /*
        !          1448:         * all non-NOP operators binary, must have at least two operands
        !          1449:         * on stack to evaluate.
        !          1450:         */
        !          1451:        if (sp > &stack[ENMAXFILTERS-2])
        !          1452:        {
        !          1453:            enprintf(ENDBG_TRACE)("=>0(sp++)\n");
        !          1454:            return(false);
        !          1455:        }
        !          1456:        arg = *sp++;
        !          1457:        switch (op)
        !          1458:        {
        !          1459:            default:
        !          1460: #ifdef INNERDEBUG
        !          1461:                enprintf(ENDBG_TRACE)("=>0(def)\n");
        !          1462: #endif
        !          1463:                return(false);
        !          1464:            case opx(ENF_AND):
        !          1465:                *sp &= arg;
        !          1466:                break;
        !          1467:            case opx(ENF_OR):
        !          1468:                *sp |= arg;
        !          1469:                break;
        !          1470:            case opx(ENF_XOR):
        !          1471:                *sp ^= arg;
        !          1472:                break;
        !          1473:            case opx(ENF_EQ):
        !          1474:                *sp = (*sp == arg);
        !          1475:                break;
        !          1476:            case opx(ENF_NEQ):
        !          1477:                *sp = (*sp != arg);
        !          1478:                break;
        !          1479:            case opx(ENF_LT):
        !          1480:                *sp = (*sp < arg);
        !          1481:                break;
        !          1482:            case opx(ENF_LE):
        !          1483:                *sp = (*sp <= arg);
        !          1484:                break;
        !          1485:            case opx(ENF_GT):
        !          1486:                *sp = (*sp > arg);
        !          1487:                break;
        !          1488:            case opx(ENF_GE):
        !          1489:                *sp = (*sp >= arg);
        !          1490:                break;
        !          1491: 
        !          1492:            /* short-circuit operators */
        !          1493: 
        !          1494:            case opx(ENF_COR):
        !          1495:                if (*sp++ == arg) {
        !          1496: #ifdef INNERDEBUG
        !          1497:                    enprintf(ENDBG_TRACE)("=>COR %x\n", *sp);
        !          1498: #endif
        !          1499:                    return(true);
        !          1500:                }
        !          1501:                break;
        !          1502:            case opx(ENF_CAND):
        !          1503:                if (*sp++ != arg) {
        !          1504: #ifdef INNERDEBUG
        !          1505:                    enprintf(ENDBG_TRACE)("=>CAND %x\n", *sp);
        !          1506: #endif
        !          1507:                    return(false);
        !          1508:                }
        !          1509:                break;
        !          1510:            case opx(ENF_CNOR):
        !          1511:                if (*sp++ == arg) {
        !          1512: #ifdef INNERDEBUG
        !          1513:                    enprintf(ENDBG_TRACE)("=>COR %x\n", *sp);
        !          1514: #endif
        !          1515:                    return(false);
        !          1516:                }
        !          1517:                break;
        !          1518:            case opx(ENF_CNAND):
        !          1519:                if (*sp++ != arg) {
        !          1520: #ifdef INNERDEBUG
        !          1521:                    enprintf(ENDBG_TRACE)("=>CAND %x\n", *sp);
        !          1522: #endif
        !          1523:                    return(true);
        !          1524:                }
        !          1525:                break;
        !          1526:        }
        !          1527:     }
        !          1528: #ifdef INNERDEBUG
        !          1529:     enprintf(ENDBG_TRACE)("=>%x\n", *sp);
        !          1530: #endif
        !          1531:     return((boolean)*sp);
        !          1532: 
        !          1533: }
        !          1534: 
        !          1535: enInitDescriptor(d, flag)
        !          1536: register struct enOpenDescriptor *d;
        !          1537: {
        !          1538: 
        !          1539: #if    DEBUG
        !          1540:     enprintf(ENDBG_TRACE)("enInitDescriptor(%x):\n", d);
        !          1541: #endif
        !          1542:     d->enOD_RecvState = ENRECVIDLE;
        !          1543:     d->enOD_OpenFilter.enf_FilterLen = 0;
        !          1544:     d->enOD_OpenFilter.enf_Priority = 0;
        !          1545:     d->enOD_FiltEnd = &(d->enOD_OpenFilter.enf_Filter[0]);
        !          1546:     d->enOD_RecvCount = 0;
        !          1547:     d->enOD_Timeout = 0;
        !          1548:     d->enOD_SigNumb = 0;
        !          1549:     d->enOD_Flag = flag;
        !          1550:     d->enOD_SelColl = 0;
        !          1551:     d->enOD_SelProc = 0;               /* probably unnecessary */
        !          1552:     /*
        !          1553:      * Remember the PID that opened us, at least until some process
        !          1554:      * sets a signal for this minor device
        !          1555:      */
        !          1556:     d->enOD_SigPid = u.u_procp->p_pid;
        !          1557: 
        !          1558:     enInitWaitQueue(&(d->enOD_Waiting));
        !          1559: #if    DEBUG
        !          1560:     enprintf(ENDBG_TRACE)("=>eninitdescriptor\n");
        !          1561: #endif
        !          1562: 
        !          1563: }
        !          1564: 
        !          1565: /*
        !          1566:  *  enInsertDescriptor - insert open descriptor in queue ordered by priority
        !          1567:  */
        !          1568: 
        !          1569: enInsertDescriptor(q, d)
        !          1570: register struct enQueue *q;
        !          1571: register struct enOpenDescriptor *d;
        !          1572: {
        !          1573:     struct enOpenDescriptor * nxt;
        !          1574:     register int ipl;
        !          1575: 
        !          1576:     ipl = splenet();
        !          1577:     nxt = (struct enOpenDescriptor *)q->enQ_F;
        !          1578:     while ((struct Queue *)q != &(nxt->enOD_Link))
        !          1579:     {
        !          1580:         if (d->enOD_OpenFilter.enf_Priority > nxt->enOD_OpenFilter.enf_Priority)
        !          1581:            break;
        !          1582:         nxt = (struct enOpenDescriptor *)nxt->enOD_Link.F;
        !          1583:     }
        !          1584:     enqueue((struct Queue *)&(nxt->enOD_Link),(struct Queue *)&(d->enOD_Link));
        !          1585:     enprintf(ENDBG_DESQ)("enID: Desq: %x, %x\n", q->enQ_F, q->enQ_B);
        !          1586:     q->enQ_NumQueued++;
        !          1587:     splx(ipl);
        !          1588: 
        !          1589: }
        !          1590: 
        !          1591: int enReorderCount = 0;                /* for external monitoring */
        !          1592: 
        !          1593: /*
        !          1594:  * enReorderQueue - swap order of two elements in queue
        !          1595:  *     assumed to be called at splenet
        !          1596:  */
        !          1597: enReorderQueue(first, last)
        !          1598: register struct Queue *first;
        !          1599: register struct Queue *last;
        !          1600: {
        !          1601:        register struct Queue *prev;
        !          1602:        register struct Queue *next;
        !          1603: 
        !          1604:        enprintf(ENDBG_DESQ)("enReorderQ: %x, %x\n", first, last);
        !          1605:        
        !          1606:        enReorderCount++;
        !          1607: 
        !          1608:        /* get pointers to other queue elements */
        !          1609:        prev = first->B;
        !          1610:        next = last->F;
        !          1611:        
        !          1612:        /*
        !          1613:         * no more reading from queue elements; this ensures that
        !          1614:         * the code works even if there are fewer than 4 elements
        !          1615:         * in the queue.
        !          1616:         */
        !          1617: 
        !          1618:        prev->F = last;
        !          1619:        next->B = first;
        !          1620:        
        !          1621:        last->B = prev;
        !          1622:        last->F = first;
        !          1623:        
        !          1624:        first->F = next;
        !          1625:        first->B = last;
        !          1626: }
        !          1627: 
        !          1628: enetattach(ifp, devp)
        !          1629: struct ifnet *ifp;
        !          1630: struct endevp *devp;
        !          1631: {
        !          1632:     register struct enState *enStatep = &enState[enUnits];
        !          1633: 
        !          1634: #ifdef DEBUG
        !          1635:     enprintf(ENDBG_INIT) ("enetattach: type %d, addr ", devp->end_dev_type);
        !          1636:     if (enDebug&ENDBG_INIT) {
        !          1637:        register int i;
        !          1638:        for (i = 0; i < devp->end_addr_len; i++)
        !          1639:            printf("%o ", devp->end_addr[i]);
        !          1640:        printf("\n");
        !          1641:     }
        !          1642: #endif DEBUG
        !          1643: 
        !          1644:     enet_info[enUnits].ifp = ifp;
        !          1645: 
        !          1646:     bcopy((caddr_t)devp, (caddr_t)&(enDevParams), sizeof(struct endevp));
        !          1647: 
        !          1648:     enInit(enStatep, enUnits);
        !          1649:     
        !          1650:     return(enUnits++);
        !          1651: }
        !          1652: 
        !          1653: #endif (NENETFILTER > 0)

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