Annotation of 43BSDTahoe/sys/net/if_loop.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1982, 1986 Regents of the University of California.
                      3:  * All rights reserved.
                      4:  *
                      5:  * Redistribution and use in source and binary forms are permitted
                      6:  * provided that the above copyright notice and this paragraph are
                      7:  * duplicated in all such forms and that any documentation,
                      8:  * advertising materials, and other materials related to such
                      9:  * distribution and use acknowledge that the software was developed
                     10:  * by the University of California, Berkeley.  The name of the
                     11:  * University may not be used to endorse or promote products derived
                     12:  * from this software without specific prior written permission.
                     13:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
                     14:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
                     15:  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
                     16:  *
                     17:  *     @(#)if_loop.c   7.4 (Berkeley) 6/27/88
                     18:  */
                     19: 
                     20: /*
                     21:  * Loopback interface driver for protocol testing and timing.
                     22:  */
                     23: 
                     24: #include "param.h"
                     25: #include "systm.h"
                     26: #include "mbuf.h"
                     27: #include "socket.h"
                     28: #include "errno.h"
                     29: #include "ioctl.h"
                     30: 
                     31: #include "../net/if.h"
                     32: #include "../net/netisr.h"
                     33: #include "../net/route.h"
                     34: 
                     35: #include "../machine/mtpr.h"
                     36: 
                     37: #ifdef INET
                     38: #include "../netinet/in.h"
                     39: #include "../netinet/in_systm.h"
                     40: #include "../netinet/in_var.h"
                     41: #include "../netinet/ip.h"
                     42: #endif
                     43: 
                     44: #ifdef NS
                     45: #include "../netns/ns.h"
                     46: #include "../netns/ns_if.h"
                     47: #endif
                     48: 
                     49: #define        LOMTU   (1024+512)
                     50: 
                     51: struct ifnet loif;
                     52: int    looutput(), loioctl();
                     53: 
                     54: loattach()
                     55: {
                     56:        register struct ifnet *ifp = &loif;
                     57: 
                     58:        ifp->if_name = "lo";
                     59:        ifp->if_mtu = LOMTU;
                     60:        ifp->if_flags = IFF_LOOPBACK;
                     61:        ifp->if_ioctl = loioctl;
                     62:        ifp->if_output = looutput;
                     63:        if_attach(ifp);
                     64: }
                     65: 
                     66: looutput(ifp, m0, dst)
                     67:        struct ifnet *ifp;
                     68:        register struct mbuf *m0;
                     69:        struct sockaddr *dst;
                     70: {
                     71:        int s;
                     72:        register struct ifqueue *ifq;
                     73:        struct mbuf *m;
                     74: 
                     75:        /*
                     76:         * Place interface pointer before the data
                     77:         * for the receiving protocol.
                     78:         */
                     79:        if (m0->m_off <= MMAXOFF &&
                     80:            m0->m_off >= MMINOFF + sizeof(struct ifnet *)) {
                     81:                m0->m_off -= sizeof(struct ifnet *);
                     82:                m0->m_len += sizeof(struct ifnet *);
                     83:        } else {
                     84:                MGET(m, M_DONTWAIT, MT_HEADER);
                     85:                if (m == (struct mbuf *)0)
                     86:                        return (ENOBUFS);
                     87:                m->m_off = MMINOFF;
                     88:                m->m_len = sizeof(struct ifnet *);
                     89:                m->m_next = m0;
                     90:                m0 = m;
                     91:        }
                     92:        *(mtod(m0, struct ifnet **)) = ifp;
                     93:        s = splimp();
                     94:        ifp->if_opackets++;
                     95:        switch (dst->sa_family) {
                     96: 
                     97: #ifdef INET
                     98:        case AF_INET:
                     99:                ifq = &ipintrq;
                    100:                if (IF_QFULL(ifq)) {
                    101:                        IF_DROP(ifq);
                    102:                        m_freem(m0);
                    103:                        splx(s);
                    104:                        return (ENOBUFS);
                    105:                }
                    106:                IF_ENQUEUE(ifq, m0);
                    107:                schednetisr(NETISR_IP);
                    108:                break;
                    109: #endif
                    110: #ifdef NS
                    111:        case AF_NS:
                    112:                ifq = &nsintrq;
                    113:                if (IF_QFULL(ifq)) {
                    114:                        IF_DROP(ifq);
                    115:                        m_freem(m0);
                    116:                        splx(s);
                    117:                        return (ENOBUFS);
                    118:                }
                    119:                IF_ENQUEUE(ifq, m0);
                    120:                schednetisr(NETISR_NS);
                    121:                break;
                    122: #endif
                    123:        default:
                    124:                splx(s);
                    125:                printf("lo%d: can't handle af%d\n", ifp->if_unit,
                    126:                        dst->sa_family);
                    127:                m_freem(m0);
                    128:                return (EAFNOSUPPORT);
                    129:        }
                    130:        ifp->if_ipackets++;
                    131:        splx(s);
                    132:        return (0);
                    133: }
                    134: 
                    135: /*
                    136:  * Process an ioctl request.
                    137:  */
                    138: /* ARGSUSED */
                    139: loioctl(ifp, cmd, data)
                    140:        register struct ifnet *ifp;
                    141:        int cmd;
                    142:        caddr_t data;
                    143: {
                    144:        int error = 0;
                    145: 
                    146:        switch (cmd) {
                    147: 
                    148:        case SIOCSIFADDR:
                    149:                ifp->if_flags |= IFF_UP;
                    150:                /*
                    151:                 * Everything else is done at a higher level.
                    152:                 */
                    153:                break;
                    154: 
                    155:        default:
                    156:                error = EINVAL;
                    157:        }
                    158:        return (error);
                    159: }

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