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Annotation of 43BSDReno/sys/netinet/tcp_usrreq.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1982, 1986, 1988 Regents of the University of California.
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * Redistribution is only permitted until one year after the first shipment
        !             6:  * of 4.4BSD by the Regents.  Otherwise, redistribution and use in source and
        !             7:  * binary forms are permitted provided that: (1) source distributions retain
        !             8:  * this entire copyright notice and comment, and (2) distributions including
        !             9:  * binaries display the following acknowledgement:  This product includes
        !            10:  * software developed by the University of California, Berkeley and its
        !            11:  * contributors'' in the documentation or other materials provided with the
        !            12:  * distribution and in all advertising materials mentioning features or use
        !            13:  * of this software.  Neither the name of the University nor the names of
        !            14:  * its contributors may be used to endorse or promote products derived from
        !            15:  * this software without specific prior written permission.
        !            16:  * THIS SOFTWARE IS PROVIDED AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
        !            17:  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
        !            18:  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            19:  *
        !            20:  *     @(#)tcp_usrreq.c        7.15 (Berkeley) 6/28/90
        !            21:  */
        !            22: 
        !            23: #include "param.h"
        !            24: #include "systm.h"
        !            25: #include "malloc.h"
        !            26: #include "mbuf.h"
        !            27: #include "socket.h"
        !            28: #include "socketvar.h"
        !            29: #include "protosw.h"
        !            30: #include "errno.h"
        !            31: #include "stat.h"
        !            32: 
        !            33: #include "../net/if.h"
        !            34: #include "../net/route.h"
        !            35: 
        !            36: #include "in.h"
        !            37: #include "in_systm.h"
        !            38: #include "ip.h"
        !            39: #include "in_pcb.h"
        !            40: #include "ip_var.h"
        !            41: #include "tcp.h"
        !            42: #include "tcp_fsm.h"
        !            43: #include "tcp_seq.h"
        !            44: #include "tcp_timer.h"
        !            45: #include "tcp_var.h"
        !            46: #include "tcpip.h"
        !            47: #include "tcp_debug.h"
        !            48: 
        !            49: /*
        !            50:  * TCP protocol interface to socket abstraction.
        !            51:  */
        !            52: extern char *tcpstates[];
        !            53: struct tcpcb *tcp_newtcpcb();
        !            54: 
        !            55: /*
        !            56:  * Process a TCP user request for TCP tb.  If this is a send request
        !            57:  * then m is the mbuf chain of send data.  If this is a timer expiration
        !            58:  * (called from the software clock routine), then timertype tells which timer.
        !            59:  */
        !            60: /*ARGSUSED*/
        !            61: tcp_usrreq(so, req, m, nam, control)
        !            62:        struct socket *so;
        !            63:        int req;
        !            64:        struct mbuf *m, *nam, *control;
        !            65: {
        !            66:        register struct inpcb *inp;
        !            67:        register struct tcpcb *tp;
        !            68:        int s;
        !            69:        int error = 0;
        !            70:        int ostate;
        !            71: 
        !            72:        if (req == PRU_CONTROL)
        !            73:                return (in_control(so, (int)m, (caddr_t)nam,
        !            74:                        (struct ifnet *)control));
        !            75:        if (control && control->m_len) {
        !            76:                m_freem(control);
        !            77:                if (m)
        !            78:                        m_freem(m);
        !            79:                return (EINVAL);
        !            80:        }
        !            81: 
        !            82:        s = splnet();
        !            83:        inp = sotoinpcb(so);
        !            84:        /*
        !            85:         * When a TCP is attached to a socket, then there will be
        !            86:         * a (struct inpcb) pointed at by the socket, and this
        !            87:         * structure will point at a subsidary (struct tcpcb).
        !            88:         */
        !            89:        if (inp == 0 && req != PRU_ATTACH) {
        !            90:                splx(s);
        !            91:                return (EINVAL);                /* XXX */
        !            92:        }
        !            93:        if (inp) {
        !            94:                tp = intotcpcb(inp);
        !            95:                /* WHAT IF TP IS 0? */
        !            96: #ifdef KPROF
        !            97:                tcp_acounts[tp->t_state][req]++;
        !            98: #endif
        !            99:                ostate = tp->t_state;
        !           100:        } else
        !           101:                ostate = 0;
        !           102:        switch (req) {
        !           103: 
        !           104:        /*
        !           105:         * TCP attaches to socket via PRU_ATTACH, reserving space,
        !           106:         * and an internet control block.
        !           107:         */
        !           108:        case PRU_ATTACH:
        !           109:                if (inp) {
        !           110:                        error = EISCONN;
        !           111:                        break;
        !           112:                }
        !           113:                error = tcp_attach(so);
        !           114:                if (error)
        !           115:                        break;
        !           116:                if ((so->so_options & SO_LINGER) && so->so_linger == 0)
        !           117:                        so->so_linger = TCP_LINGERTIME;
        !           118:                tp = sototcpcb(so);
        !           119:                break;
        !           120: 
        !           121:        /*
        !           122:         * PRU_DETACH detaches the TCP protocol from the socket.
        !           123:         * If the protocol state is non-embryonic, then can't
        !           124:         * do this directly: have to initiate a PRU_DISCONNECT,
        !           125:         * which may finish later; embryonic TCB's can just
        !           126:         * be discarded here.
        !           127:         */
        !           128:        case PRU_DETACH:
        !           129:                if (tp->t_state > TCPS_LISTEN)
        !           130:                        tp = tcp_disconnect(tp);
        !           131:                else
        !           132:                        tp = tcp_close(tp);
        !           133:                break;
        !           134: 
        !           135:        /*
        !           136:         * Give the socket an address.
        !           137:         */
        !           138:        case PRU_BIND:
        !           139:                error = in_pcbbind(inp, nam);
        !           140:                if (error)
        !           141:                        break;
        !           142:                break;
        !           143: 
        !           144:        /*
        !           145:         * Prepare to accept connections.
        !           146:         */
        !           147:        case PRU_LISTEN:
        !           148:                if (inp->inp_lport == 0)
        !           149:                        error = in_pcbbind(inp, (struct mbuf *)0);
        !           150:                if (error == 0)
        !           151:                        tp->t_state = TCPS_LISTEN;
        !           152:                break;
        !           153: 
        !           154:        /*
        !           155:         * Initiate connection to peer.
        !           156:         * Create a template for use in transmissions on this connection.
        !           157:         * Enter SYN_SENT state, and mark socket as connecting.
        !           158:         * Start keep-alive timer, and seed output sequence space.
        !           159:         * Send initial segment on connection.
        !           160:         */
        !           161:        case PRU_CONNECT:
        !           162:                if (inp->inp_lport == 0) {
        !           163:                        error = in_pcbbind(inp, (struct mbuf *)0);
        !           164:                        if (error)
        !           165:                                break;
        !           166:                }
        !           167:                error = in_pcbconnect(inp, nam);
        !           168:                if (error)
        !           169:                        break;
        !           170:                tp->t_template = tcp_template(tp);
        !           171:                if (tp->t_template == 0) {
        !           172:                        in_pcbdisconnect(inp);
        !           173:                        error = ENOBUFS;
        !           174:                        break;
        !           175:                }
        !           176:                soisconnecting(so);
        !           177:                tcpstat.tcps_connattempt++;
        !           178:                tp->t_state = TCPS_SYN_SENT;
        !           179:                tp->t_timer[TCPT_KEEP] = TCPTV_KEEP_INIT;
        !           180:                tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2;
        !           181:                tcp_sendseqinit(tp);
        !           182:                error = tcp_output(tp);
        !           183:                break;
        !           184: 
        !           185:        /*
        !           186:         * Create a TCP connection between two sockets.
        !           187:         */
        !           188:        case PRU_CONNECT2:
        !           189:                error = EOPNOTSUPP;
        !           190:                break;
        !           191: 
        !           192:        /*
        !           193:         * Initiate disconnect from peer.
        !           194:         * If connection never passed embryonic stage, just drop;
        !           195:         * else if don't need to let data drain, then can just drop anyways,
        !           196:         * else have to begin TCP shutdown process: mark socket disconnecting,
        !           197:         * drain unread data, state switch to reflect user close, and
        !           198:         * send segment (e.g. FIN) to peer.  Socket will be really disconnected
        !           199:         * when peer sends FIN and acks ours.
        !           200:         *
        !           201:         * SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
        !           202:         */
        !           203:        case PRU_DISCONNECT:
        !           204:                tp = tcp_disconnect(tp);
        !           205:                break;
        !           206: 
        !           207:        /*
        !           208:         * Accept a connection.  Essentially all the work is
        !           209:         * done at higher levels; just return the address
        !           210:         * of the peer, storing through addr.
        !           211:         */
        !           212:        case PRU_ACCEPT: {
        !           213:                struct sockaddr_in *sin = mtod(nam, struct sockaddr_in *);
        !           214: 
        !           215:                nam->m_len = sizeof (struct sockaddr_in);
        !           216:                sin->sin_family = AF_INET;
        !           217:                sin->sin_len = sizeof(*sin);
        !           218:                sin->sin_port = inp->inp_fport;
        !           219:                sin->sin_addr = inp->inp_faddr;
        !           220:                break;
        !           221:                }
        !           222: 
        !           223:        /*
        !           224:         * Mark the connection as being incapable of further output.
        !           225:         */
        !           226:        case PRU_SHUTDOWN:
        !           227:                socantsendmore(so);
        !           228:                tp = tcp_usrclosed(tp);
        !           229:                if (tp)
        !           230:                        error = tcp_output(tp);
        !           231:                break;
        !           232: 
        !           233:        /*
        !           234:         * After a receive, possibly send window update to peer.
        !           235:         */
        !           236:        case PRU_RCVD:
        !           237:                (void) tcp_output(tp);
        !           238:                break;
        !           239: 
        !           240:        /*
        !           241:         * Do a send by putting data in output queue and updating urgent
        !           242:         * marker if URG set.  Possibly send more data.
        !           243:         */
        !           244:        case PRU_SEND:
        !           245:                sbappend(&so->so_snd, m);
        !           246:                error = tcp_output(tp);
        !           247:                break;
        !           248: 
        !           249:        /*
        !           250:         * Abort the TCP.
        !           251:         */
        !           252:        case PRU_ABORT:
        !           253:                tp = tcp_drop(tp, ECONNABORTED);
        !           254:                break;
        !           255: 
        !           256:        case PRU_SENSE:
        !           257:                ((struct stat *) m)->st_blksize = so->so_snd.sb_hiwat;
        !           258:                (void) splx(s);
        !           259:                return (0);
        !           260: 
        !           261:        case PRU_RCVOOB:
        !           262:                if ((so->so_oobmark == 0 &&
        !           263:                    (so->so_state & SS_RCVATMARK) == 0) ||
        !           264:                    so->so_options & SO_OOBINLINE ||
        !           265:                    tp->t_oobflags & TCPOOB_HADDATA) {
        !           266:                        error = EINVAL;
        !           267:                        break;
        !           268:                }
        !           269:                if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
        !           270:                        error = EWOULDBLOCK;
        !           271:                        break;
        !           272:                }
        !           273:                m->m_len = 1;
        !           274:                *mtod(m, caddr_t) = tp->t_iobc;
        !           275:                if (((int)nam & MSG_PEEK) == 0)
        !           276:                        tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
        !           277:                break;
        !           278: 
        !           279:        case PRU_SENDOOB:
        !           280:                if (sbspace(&so->so_snd) < -512) {
        !           281:                        m_freem(m);
        !           282:                        error = ENOBUFS;
        !           283:                        break;
        !           284:                }
        !           285:                /*
        !           286:                 * According to RFC961 (Assigned Protocols),
        !           287:                 * the urgent pointer points to the last octet
        !           288:                 * of urgent data.  We continue, however,
        !           289:                 * to consider it to indicate the first octet
        !           290:                 * of data past the urgent section.
        !           291:                 * Otherwise, snd_up should be one lower.
        !           292:                 */
        !           293:                sbappend(&so->so_snd, m);
        !           294:                tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
        !           295:                tp->t_force = 1;
        !           296:                error = tcp_output(tp);
        !           297:                tp->t_force = 0;
        !           298:                break;
        !           299: 
        !           300:        case PRU_SOCKADDR:
        !           301:                in_setsockaddr(inp, nam);
        !           302:                break;
        !           303: 
        !           304:        case PRU_PEERADDR:
        !           305:                in_setpeeraddr(inp, nam);
        !           306:                break;
        !           307: 
        !           308:        /*
        !           309:         * TCP slow timer went off; going through this
        !           310:         * routine for tracing's sake.
        !           311:         */
        !           312:        case PRU_SLOWTIMO:
        !           313:                tp = tcp_timers(tp, (int)nam);
        !           314:                req |= (int)nam << 8;           /* for debug's sake */
        !           315:                break;
        !           316: 
        !           317:        default:
        !           318:                panic("tcp_usrreq");
        !           319:        }
        !           320:        if (tp && (so->so_options & SO_DEBUG))
        !           321:                tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req);
        !           322:        splx(s);
        !           323:        return (error);
        !           324: }
        !           325: 
        !           326: tcp_ctloutput(op, so, level, optname, mp)
        !           327:        int op;
        !           328:        struct socket *so;
        !           329:        int level, optname;
        !           330:        struct mbuf **mp;
        !           331: {
        !           332:        int error = 0;
        !           333:        struct inpcb *inp = sotoinpcb(so);
        !           334:        register struct tcpcb *tp = intotcpcb(inp);
        !           335:        register struct mbuf *m;
        !           336: 
        !           337:        if (level != IPPROTO_TCP)
        !           338:                return (ip_ctloutput(op, so, level, optname, mp));
        !           339: 
        !           340:        switch (op) {
        !           341: 
        !           342:        case PRCO_SETOPT:
        !           343:                m = *mp;
        !           344:                switch (optname) {
        !           345: 
        !           346:                case TCP_NODELAY:
        !           347:                        if (m == NULL || m->m_len < sizeof (int))
        !           348:                                error = EINVAL;
        !           349:                        else if (*mtod(m, int *))
        !           350:                                tp->t_flags |= TF_NODELAY;
        !           351:                        else
        !           352:                                tp->t_flags &= ~TF_NODELAY;
        !           353:                        break;
        !           354: 
        !           355:                case TCP_MAXSEG:        /* not yet */
        !           356:                default:
        !           357:                        error = EINVAL;
        !           358:                        break;
        !           359:                }
        !           360:                if (m)
        !           361:                        (void) m_free(m);
        !           362:                break;
        !           363: 
        !           364:        case PRCO_GETOPT:
        !           365:                *mp = m = m_get(M_WAIT, MT_SOOPTS);
        !           366:                m->m_len = sizeof(int);
        !           367: 
        !           368:                switch (optname) {
        !           369:                case TCP_NODELAY:
        !           370:                        *mtod(m, int *) = tp->t_flags & TF_NODELAY;
        !           371:                        break;
        !           372:                case TCP_MAXSEG:
        !           373:                        *mtod(m, int *) = tp->t_maxseg;
        !           374:                        break;
        !           375:                default:
        !           376:                        error = EINVAL;
        !           377:                        break;
        !           378:                }
        !           379:                break;
        !           380:        }
        !           381:        return (error);
        !           382: }
        !           383: 
        !           384: u_long tcp_sendspace = 1024*4;
        !           385: u_long tcp_recvspace = 1024*4;
        !           386: 
        !           387: /*
        !           388:  * Attach TCP protocol to socket, allocating
        !           389:  * internet protocol control block, tcp control block,
        !           390:  * bufer space, and entering LISTEN state if to accept connections.
        !           391:  */
        !           392: tcp_attach(so)
        !           393:        struct socket *so;
        !           394: {
        !           395:        register struct tcpcb *tp;
        !           396:        struct inpcb *inp;
        !           397:        int error;
        !           398: 
        !           399:        if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
        !           400:                error = soreserve(so, tcp_sendspace, tcp_recvspace);
        !           401:                if (error)
        !           402:                        return (error);
        !           403:        }
        !           404:        error = in_pcballoc(so, &tcb);
        !           405:        if (error)
        !           406:                return (error);
        !           407:        inp = sotoinpcb(so);
        !           408:        tp = tcp_newtcpcb(inp);
        !           409:        if (tp == 0) {
        !           410:                int nofd = so->so_state & SS_NOFDREF;   /* XXX */
        !           411: 
        !           412:                so->so_state &= ~SS_NOFDREF;    /* don't free the socket yet */
        !           413:                in_pcbdetach(inp);
        !           414:                so->so_state |= nofd;
        !           415:                return (ENOBUFS);
        !           416:        }
        !           417:        tp->t_state = TCPS_CLOSED;
        !           418:        return (0);
        !           419: }
        !           420: 
        !           421: /*
        !           422:  * Initiate (or continue) disconnect.
        !           423:  * If embryonic state, just send reset (once).
        !           424:  * If in ``let data drain'' option and linger null, just drop.
        !           425:  * Otherwise (hard), mark socket disconnecting and drop
        !           426:  * current input data; switch states based on user close, and
        !           427:  * send segment to peer (with FIN).
        !           428:  */
        !           429: struct tcpcb *
        !           430: tcp_disconnect(tp)
        !           431:        register struct tcpcb *tp;
        !           432: {
        !           433:        struct socket *so = tp->t_inpcb->inp_socket;
        !           434: 
        !           435:        if (tp->t_state < TCPS_ESTABLISHED)
        !           436:                tp = tcp_close(tp);
        !           437:        else if ((so->so_options & SO_LINGER) && so->so_linger == 0)
        !           438:                tp = tcp_drop(tp, 0);
        !           439:        else {
        !           440:                soisdisconnecting(so);
        !           441:                sbflush(&so->so_rcv);
        !           442:                tp = tcp_usrclosed(tp);
        !           443:                if (tp)
        !           444:                        (void) tcp_output(tp);
        !           445:        }
        !           446:        return (tp);
        !           447: }
        !           448: 
        !           449: /*
        !           450:  * User issued close, and wish to trail through shutdown states:
        !           451:  * if never received SYN, just forget it.  If got a SYN from peer,
        !           452:  * but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
        !           453:  * If already got a FIN from peer, then almost done; go to LAST_ACK
        !           454:  * state.  In all other cases, have already sent FIN to peer (e.g.
        !           455:  * after PRU_SHUTDOWN), and just have to play tedious game waiting
        !           456:  * for peer to send FIN or not respond to keep-alives, etc.
        !           457:  * We can let the user exit from the close as soon as the FIN is acked.
        !           458:  */
        !           459: struct tcpcb *
        !           460: tcp_usrclosed(tp)
        !           461:        register struct tcpcb *tp;
        !           462: {
        !           463: 
        !           464:        switch (tp->t_state) {
        !           465: 
        !           466:        case TCPS_CLOSED:
        !           467:        case TCPS_LISTEN:
        !           468:        case TCPS_SYN_SENT:
        !           469:                tp->t_state = TCPS_CLOSED;
        !           470:                tp = tcp_close(tp);
        !           471:                break;
        !           472: 
        !           473:        case TCPS_SYN_RECEIVED:
        !           474:        case TCPS_ESTABLISHED:
        !           475:                tp->t_state = TCPS_FIN_WAIT_1;
        !           476:                break;
        !           477: 
        !           478:        case TCPS_CLOSE_WAIT:
        !           479:                tp->t_state = TCPS_LAST_ACK;
        !           480:                break;
        !           481:        }
        !           482:        if (tp && tp->t_state >= TCPS_FIN_WAIT_2)
        !           483:                soisdisconnected(tp->t_inpcb->inp_socket);
        !           484:        return (tp);
        !           485: }

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