Annotation of 43BSD/etc/routed/tables.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1983 Regents of the University of California.
        !             3:  * All rights reserved.  The Berkeley software License Agreement
        !             4:  * specifies the terms and conditions for redistribution.
        !             5:  */
        !             6: 
        !             7: #ifndef lint
        !             8: static char sccsid[] = "@(#)tables.c   5.5 (Berkeley) 5/28/86";
        !             9: #endif not lint
        !            10: 
        !            11: /*
        !            12:  * Routing Table Management Daemon
        !            13:  */
        !            14: #include "defs.h"
        !            15: #include <sys/ioctl.h>
        !            16: #include <errno.h>
        !            17: #include <syslog.h>
        !            18: 
        !            19: #ifndef DEBUG
        !            20: #define        DEBUG   0
        !            21: #endif
        !            22: 
        !            23: int    install = !DEBUG;               /* if 1 call kernel */
        !            24: 
        !            25: /*
        !            26:  * Lookup dst in the tables for an exact match.
        !            27:  */
        !            28: struct rt_entry *
        !            29: rtlookup(dst)
        !            30:        struct sockaddr *dst;
        !            31: {
        !            32:        register struct rt_entry *rt;
        !            33:        register struct rthash *rh;
        !            34:        register u_int hash;
        !            35:        struct afhash h;
        !            36:        int doinghost = 1;
        !            37: 
        !            38:        if (dst->sa_family >= af_max)
        !            39:                return (0);
        !            40:        (*afswitch[dst->sa_family].af_hash)(dst, &h);
        !            41:        hash = h.afh_hosthash;
        !            42:        rh = &hosthash[hash & ROUTEHASHMASK];
        !            43: again:
        !            44:        for (rt = rh->rt_forw; rt != (struct rt_entry *)rh; rt = rt->rt_forw) {
        !            45:                if (rt->rt_hash != hash)
        !            46:                        continue;
        !            47:                if (equal(&rt->rt_dst, dst))
        !            48:                        return (rt);
        !            49:        }
        !            50:        if (doinghost) {
        !            51:                doinghost = 0;
        !            52:                hash = h.afh_nethash;
        !            53:                rh = &nethash[hash & ROUTEHASHMASK];
        !            54:                goto again;
        !            55:        }
        !            56:        return (0);
        !            57: }
        !            58: 
        !            59: /*
        !            60:  * Find a route to dst as the kernel would.
        !            61:  */
        !            62: struct rt_entry *
        !            63: rtfind(dst)
        !            64:        struct sockaddr *dst;
        !            65: {
        !            66:        register struct rt_entry *rt;
        !            67:        register struct rthash *rh;
        !            68:        register u_int hash;
        !            69:        struct afhash h;
        !            70:        int af = dst->sa_family;
        !            71:        int doinghost = 1, (*match)();
        !            72: 
        !            73:        if (af >= af_max)
        !            74:                return (0);
        !            75:        (*afswitch[af].af_hash)(dst, &h);
        !            76:        hash = h.afh_hosthash;
        !            77:        rh = &hosthash[hash & ROUTEHASHMASK];
        !            78: 
        !            79: again:
        !            80:        for (rt = rh->rt_forw; rt != (struct rt_entry *)rh; rt = rt->rt_forw) {
        !            81:                if (rt->rt_hash != hash)
        !            82:                        continue;
        !            83:                if (doinghost) {
        !            84:                        if (equal(&rt->rt_dst, dst))
        !            85:                                return (rt);
        !            86:                } else {
        !            87:                        if (rt->rt_dst.sa_family == af &&
        !            88:                            (*match)(&rt->rt_dst, dst))
        !            89:                                return (rt);
        !            90:                }
        !            91:        }
        !            92:        if (doinghost) {
        !            93:                doinghost = 0;
        !            94:                hash = h.afh_nethash;
        !            95:                rh = &nethash[hash & ROUTEHASHMASK];
        !            96:                match = afswitch[af].af_netmatch;
        !            97:                goto again;
        !            98:        }
        !            99:        return (0);
        !           100: }
        !           101: 
        !           102: rtadd(dst, gate, metric, state)
        !           103:        struct sockaddr *dst, *gate;
        !           104:        int metric, state;
        !           105: {
        !           106:        struct afhash h;
        !           107:        register struct rt_entry *rt;
        !           108:        struct rthash *rh;
        !           109:        int af = dst->sa_family, flags;
        !           110:        u_int hash;
        !           111: 
        !           112:        if (af >= af_max)
        !           113:                return;
        !           114:        (*afswitch[af].af_hash)(dst, &h);
        !           115:        flags = (*afswitch[af].af_rtflags)(dst);
        !           116:        /*
        !           117:         * Subnet flag isn't visible to kernel, move to state.  XXX
        !           118:         */
        !           119:        if (flags & RTF_SUBNET) {
        !           120:                state |= RTS_SUBNET;
        !           121:                flags &= ~RTF_SUBNET;
        !           122:        }
        !           123:        if (flags & RTF_HOST) {
        !           124:                hash = h.afh_hosthash;
        !           125:                rh = &hosthash[hash & ROUTEHASHMASK];
        !           126:        } else {
        !           127:                hash = h.afh_nethash;
        !           128:                rh = &nethash[hash & ROUTEHASHMASK];
        !           129:        }
        !           130:        rt = (struct rt_entry *)malloc(sizeof (*rt));
        !           131:        if (rt == 0)
        !           132:                return;
        !           133:        rt->rt_hash = hash;
        !           134:        rt->rt_dst = *dst;
        !           135:        rt->rt_router = *gate;
        !           136:        rt->rt_metric = metric;
        !           137:        rt->rt_timer = 0;
        !           138:        rt->rt_flags = RTF_UP | flags;
        !           139:        rt->rt_state = state | RTS_CHANGED;
        !           140:        rt->rt_ifp = if_ifwithdstaddr(&rt->rt_router);
        !           141:        if (rt->rt_ifp == 0)
        !           142:                rt->rt_ifp = if_ifwithnet(&rt->rt_router);
        !           143:        if (metric)
        !           144:                rt->rt_flags |= RTF_GATEWAY;
        !           145:        insque(rt, rh);
        !           146:        TRACE_ACTION(ADD, rt);
        !           147:        /*
        !           148:         * If the ioctl fails because the gateway is unreachable
        !           149:         * from this host, discard the entry.  This should only
        !           150:         * occur because of an incorrect entry in /etc/gateways.
        !           151:         */
        !           152:        if (install && (rt->rt_state & (RTS_INTERNAL | RTS_EXTERNAL)) == 0 &&
        !           153:            ioctl(s, SIOCADDRT, (char *)&rt->rt_rt) < 0) {
        !           154:                perror("SIOCADDRT");
        !           155:                if (errno == ENETUNREACH) {
        !           156:                        TRACE_ACTION(DELETE, rt);
        !           157:                        remque(rt);
        !           158:                        free((char *)rt);
        !           159:                }
        !           160:        }
        !           161: }
        !           162: 
        !           163: rtchange(rt, gate, metric)
        !           164:        struct rt_entry *rt;
        !           165:        struct sockaddr *gate;
        !           166:        short metric;
        !           167: {
        !           168:        int doioctl = 0, metricchanged = 0;
        !           169:        struct rtentry oldroute;
        !           170: 
        !           171:        if (!equal(&rt->rt_router, gate) && (rt->rt_state & RTS_INTERNAL) == 0)
        !           172:                doioctl++;
        !           173:        if (metric != rt->rt_metric)
        !           174:                metricchanged++;
        !           175:        if (doioctl || metricchanged) {
        !           176:                TRACE_ACTION(CHANGE FROM, rt);
        !           177:                if ((rt->rt_state & RTS_INTERFACE) && metric) {
        !           178:                        rt->rt_state &= ~RTS_INTERFACE;
        !           179:                        syslog(LOG_ERR,
        !           180:                                "changing route from interface %s (timed out)",
        !           181:                                rt->rt_ifp->int_name);
        !           182:                }
        !           183:                if (doioctl) {
        !           184:                        oldroute = rt->rt_rt;
        !           185:                        rt->rt_router = *gate;
        !           186:                        rt->rt_ifp = if_ifwithdstaddr(&rt->rt_router);
        !           187:                        if (rt->rt_ifp == 0)
        !           188:                                rt->rt_ifp = if_ifwithnet(&rt->rt_router);
        !           189:                }
        !           190:                rt->rt_metric = metric;
        !           191:                if (metric)
        !           192:                        rt->rt_flags |= RTF_GATEWAY;
        !           193:                else
        !           194:                        rt->rt_flags &= ~RTF_GATEWAY;
        !           195:                rt->rt_state |= RTS_CHANGED;
        !           196:                TRACE_ACTION(CHANGE TO, rt);
        !           197:        }
        !           198:        if (doioctl && install) {
        !           199:                if (ioctl(s, SIOCADDRT, (char *)&rt->rt_rt) < 0)
        !           200:                        perror("SIOCADDRT");
        !           201:                if (ioctl(s, SIOCDELRT, (char *)&oldroute) < 0)
        !           202:                        perror("SIOCDELRT");
        !           203:        }
        !           204: }
        !           205: 
        !           206: rtdelete(rt)
        !           207:        struct rt_entry *rt;
        !           208: {
        !           209: 
        !           210:        if (rt->rt_state & RTS_INTERFACE)
        !           211:                syslog(LOG_ERR, "deleting route to interface %s (timed out)",
        !           212:                        rt->rt_ifp->int_name);
        !           213:        TRACE_ACTION(DELETE, rt);
        !           214:        if (install && (rt->rt_state & (RTS_INTERNAL | RTS_EXTERNAL)) == 0 &&
        !           215:            ioctl(s, SIOCDELRT, (char *)&rt->rt_rt))
        !           216:                perror("SIOCDELRT");
        !           217:        remque(rt);
        !           218:        free((char *)rt);
        !           219: }
        !           220: 
        !           221: /*
        !           222:  * If we have an interface to the wide, wide world,
        !           223:  * add an entry for an Internet default route (wildcard) to the internal
        !           224:  * tables and advertise it.  This route is not added to the kernel routes,
        !           225:  * but this entry prevents us from listening to other people's defaults
        !           226:  * and installing them in the kernel here.
        !           227:  */
        !           228: rtdefault()
        !           229: {
        !           230:        extern struct sockaddr inet_default;
        !           231: 
        !           232:        rtadd(&inet_default, &inet_default, 0,
        !           233:                RTS_CHANGED | RTS_PASSIVE | RTS_INTERNAL);
        !           234: }
        !           235: 
        !           236: rtinit()
        !           237: {
        !           238:        register struct rthash *rh;
        !           239: 
        !           240:        for (rh = nethash; rh < &nethash[ROUTEHASHSIZ]; rh++)
        !           241:                rh->rt_forw = rh->rt_back = (struct rt_entry *)rh;
        !           242:        for (rh = hosthash; rh < &hosthash[ROUTEHASHSIZ]; rh++)
        !           243:                rh->rt_forw = rh->rt_back = (struct rt_entry *)rh;
        !           244: }

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