4.3BSD - /usr/src/sys/net/route.c

   1: /*
   2:  * Copyright (c) 1980, 1986 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:  *	@(#)route.c	7.1 (Berkeley) 6/4/86
   7:  */
   8: 
   9: #include "param.h"
  10: #include "systm.h"
  11: #include "mbuf.h"
  12: #include "protosw.h"
  13: #include "socket.h"
  14: #include "dir.h"
  15: #include "user.h"
  16: #include "ioctl.h"
  17: #include "errno.h"
  18: 
  19: #include "if.h"
  20: #include "af.h"
  21: #include "route.h"
  22: 
  23: int rttrash;        /* routes not in table but not freed */
  24: struct  sockaddr wildcard;  /* zero valued cookie for wildcard searches */
  25: int rthashsize = RTHASHSIZ; /* for netstat, etc. */
  26: 
  27: /*
  28:  * Packet routing routines.
  29:  */
  30: rtalloc(ro)
  31:     register struct route *ro;
  32: {
  33:     register struct rtentry *rt;
  34:     register struct mbuf *m;
  35:     register u_long hash;
  36:     struct sockaddr *dst = &ro->ro_dst;
  37:     int (*match)(), doinghost, s;
  38:     struct afhash h;
  39:     u_int af = dst->sa_family;
  40:     struct mbuf **table;
  41: 
  42:     if (ro->ro_rt && ro->ro_rt->rt_ifp && (ro->ro_rt->rt_flags & RTF_UP))
  43:         return;              /* XXX */
  44:     if (af >= AF_MAX)
  45:         return;
  46:     (*afswitch[af].af_hash)(dst, &h);
  47:     match = afswitch[af].af_netmatch;
  48:     hash = h.afh_hosthash, table = rthost, doinghost = 1;
  49:     s = splnet();
  50: again:
  51:     for (m = table[RTHASHMOD(hash)]; m; m = m->m_next) {
  52:         rt = mtod(m, struct rtentry *);
  53:         if (rt->rt_hash != hash)
  54:             continue;
  55:         if ((rt->rt_flags & RTF_UP) == 0 ||
  56:             (rt->rt_ifp->if_flags & IFF_UP) == 0)
  57:             continue;
  58:         if (doinghost) {
  59:             if (bcmp((caddr_t)&rt->rt_dst, (caddr_t)dst,
  60:                 sizeof (*dst)))
  61:                 continue;
  62:         } else {
  63:             if (rt->rt_dst.sa_family != af ||
  64:                 !(*match)(&rt->rt_dst, dst))
  65:                 continue;
  66:         }
  67:         rt->rt_refcnt++;
  68:         splx(s);
  69:         if (dst == &wildcard)
  70:             rtstat.rts_wildcard++;
  71:         ro->ro_rt = rt;
  72:         return;
  73:     }
  74:     if (doinghost) {
  75:         doinghost = 0;
  76:         hash = h.afh_nethash, table = rtnet;
  77:         goto again;
  78:     }
  79:     /*
  80: 	 * Check for wildcard gateway, by convention network 0.
  81: 	 */
  82:     if (dst != &wildcard) {
  83:         dst = &wildcard, hash = 0;
  84:         goto again;
  85:     }
  86:     splx(s);
  87:     rtstat.rts_unreach++;
  88: }
  89: 
  90: rtfree(rt)
  91:     register struct rtentry *rt;
  92: {
  93: 
  94:     if (rt == 0)
  95:         panic("rtfree");
  96:     rt->rt_refcnt--;
  97:     if (rt->rt_refcnt == 0 && (rt->rt_flags&RTF_UP) == 0) {
  98:         rttrash--;
  99:         (void) m_free(dtom(rt));
 100:     }
 101: }
 102: 
 103: /*
 104:  * Force a routing table entry to the specified
 105:  * destination to go through the given gateway.
 106:  * Normally called as a result of a routing redirect
 107:  * message from the network layer.
 108:  *
 109:  * N.B.: must be called at splnet or higher
 110:  *
 111:  */
 112: rtredirect(dst, gateway, flags, src)
 113:     struct sockaddr *dst, *gateway, *src;
 114:     int flags;
 115: {
 116:     struct route ro;
 117:     register struct rtentry *rt;
 118: 
 119:     /* verify the gateway is directly reachable */
 120:     if (ifa_ifwithnet(gateway) == 0) {
 121:         rtstat.rts_badredirect++;
 122:         return;
 123:     }
 124:     ro.ro_dst = *dst;
 125:     ro.ro_rt = 0;
 126:     rtalloc(&ro);
 127:     rt = ro.ro_rt;
 128: #define equal(a1, a2) \
 129:     (bcmp((caddr_t)(a1), (caddr_t)(a2), sizeof(struct sockaddr)) == 0)
 130:     /*
 131: 	 * If the redirect isn't from our current router for this dst,
 132: 	 * it's either old or wrong.  If it redirects us to ourselves,
 133: 	 * we have a routing loop, perhaps as a result of an interface
 134: 	 * going down recently.
 135: 	 */
 136:     if ((rt && !equal(src, &rt->rt_gateway)) || ifa_ifwithaddr(gateway)) {
 137:         rtstat.rts_badredirect++;
 138:         if (rt)
 139:             rtfree(rt);
 140:         return;
 141:     }
 142:     /*
 143: 	 * Create a new entry if we just got back a wildcard entry
 144: 	 * or the the lookup failed.  This is necessary for hosts
 145: 	 * which use routing redirects generated by smart gateways
 146: 	 * to dynamically build the routing tables.
 147: 	 */
 148:     if (rt &&
 149:         (*afswitch[dst->sa_family].af_netmatch)(&wildcard, &rt->rt_dst)) {
 150:         rtfree(rt);
 151:         rt = 0;
 152:     }
 153:     if (rt == 0) {
 154:         rtinit(dst, gateway, (int)SIOCADDRT,
 155:             (flags & RTF_HOST) | RTF_GATEWAY | RTF_DYNAMIC);
 156:         rtstat.rts_dynamic++;
 157:         return;
 158:     }
 159:     /*
 160: 	 * Don't listen to the redirect if it's
 161: 	 * for a route to an interface.
 162: 	 */
 163:     if (rt->rt_flags & RTF_GATEWAY) {
 164:         if (((rt->rt_flags & RTF_HOST) == 0) && (flags & RTF_HOST)) {
 165:             /*
 166: 			 * Changing from route to net => route to host.
 167: 			 * Create new route, rather than smashing route to net.
 168: 			 */
 169:             rtinit(dst, gateway, (int)SIOCADDRT,
 170:                 flags | RTF_DYNAMIC);
 171:             rtstat.rts_dynamic++;
 172:         } else {
 173:             /*
 174: 			 * Smash the current notion of the gateway to
 175: 			 * this destination.
 176: 			 */
 177:             rt->rt_gateway = *gateway;
 178:         }
 179:         rtstat.rts_newgateway++;
 180:     } else
 181:         rtstat.rts_badredirect++;
 182:     rtfree(rt);
 183: }
 184: 
 185: /*
 186:  * Routing table ioctl interface.
 187:  */
 188: rtioctl(cmd, data)
 189:     int cmd;
 190:     caddr_t data;
 191: {
 192: 
 193:     if (cmd != SIOCADDRT && cmd != SIOCDELRT)
 194:         return (EINVAL);
 195:     if (!suser())
 196:         return (u.u_error);
 197:     return (rtrequest(cmd, (struct rtentry *)data));
 198: }
 199: 
 200: /*
 201:  * Carry out a request to change the routing table.  Called by
 202:  * interfaces at boot time to make their ``local routes'' known,
 203:  * for ioctl's, and as the result of routing redirects.
 204:  */
 205: rtrequest(req, entry)
 206:     int req;
 207:     register struct rtentry *entry;
 208: {
 209:     register struct mbuf *m, **mprev;
 210:     struct mbuf **mfirst;
 211:     register struct rtentry *rt;
 212:     struct afhash h;
 213:     int s, error = 0, (*match)();
 214:     u_int af;
 215:     u_long hash;
 216:     struct ifaddr *ifa;
 217:     struct ifaddr *ifa_ifwithdstaddr();
 218: 
 219:     af = entry->rt_dst.sa_family;
 220:     if (af >= AF_MAX)
 221:         return (EAFNOSUPPORT);
 222:     (*afswitch[af].af_hash)(&entry->rt_dst, &h);
 223:     if (entry->rt_flags & RTF_HOST) {
 224:         hash = h.afh_hosthash;
 225:         mprev = &rthost[RTHASHMOD(hash)];
 226:     } else {
 227:         hash = h.afh_nethash;
 228:         mprev = &rtnet[RTHASHMOD(hash)];
 229:     }
 230:     match = afswitch[af].af_netmatch;
 231:     s = splimp();
 232:     for (mfirst = mprev; m = *mprev; mprev = &m->m_next) {
 233:         rt = mtod(m, struct rtentry *);
 234:         if (rt->rt_hash != hash)
 235:             continue;
 236:         if (entry->rt_flags & RTF_HOST) {
 237:             if (!equal(&rt->rt_dst, &entry->rt_dst))
 238:                 continue;
 239:         } else {
 240:             if (rt->rt_dst.sa_family != entry->rt_dst.sa_family ||
 241:                 (*match)(&rt->rt_dst, &entry->rt_dst) == 0)
 242:                 continue;
 243:         }
 244:         if (equal(&rt->rt_gateway, &entry->rt_gateway))
 245:             break;
 246:     }
 247:     switch (req) {
 248: 
 249:     case SIOCDELRT:
 250:         if (m == 0) {
 251:             error = ESRCH;
 252:             goto bad;
 253:         }
 254:         *mprev = m->m_next;
 255:         if (rt->rt_refcnt > 0) {
 256:             rt->rt_flags &= ~RTF_UP;
 257:             rttrash++;
 258:             m->m_next = 0;
 259:         } else
 260:             (void) m_free(m);
 261:         break;
 262: 
 263:     case SIOCADDRT:
 264:         if (m) {
 265:             error = EEXIST;
 266:             goto bad;
 267:         }
 268:         if ((entry->rt_flags & RTF_GATEWAY) == 0) {
 269:             /*
 270: 			 * If we are adding a route to an interface,
 271: 			 * and the interface is a pt to pt link
 272: 			 * we should search for the destination
 273: 			 * as our clue to the interface.  Otherwise
 274: 			 * we can use the local address.
 275: 			 */
 276:             ifa = 0;
 277:             if (entry->rt_flags & RTF_HOST)
 278:                 ifa = ifa_ifwithdstaddr(&entry->rt_dst);
 279:             if (ifa == 0)
 280:                 ifa = ifa_ifwithaddr(&entry->rt_gateway);
 281:         } else {
 282:             /*
 283: 			 * If we are adding a route to a remote net
 284: 			 * or host, the gateway may still be on the
 285: 			 * other end of a pt to pt link.
 286: 			 */
 287:             ifa = ifa_ifwithdstaddr(&entry->rt_gateway);
 288:         }
 289:         if (ifa == 0) {
 290:             ifa = ifa_ifwithnet(&entry->rt_gateway);
 291:             if (ifa == 0) {
 292:                 error = ENETUNREACH;
 293:                 goto bad;
 294:             }
 295:         }
 296:         m = m_get(M_DONTWAIT, MT_RTABLE);
 297:         if (m == 0) {
 298:             error = ENOBUFS;
 299:             goto bad;
 300:         }
 301:         m->m_next = *mfirst;
 302:         *mfirst = m;
 303:         m->m_off = MMINOFF;
 304:         m->m_len = sizeof (struct rtentry);
 305:         rt = mtod(m, struct rtentry *);
 306:         rt->rt_hash = hash;
 307:         rt->rt_dst = entry->rt_dst;
 308:         rt->rt_gateway = entry->rt_gateway;
 309:         rt->rt_flags = RTF_UP |
 310:             (entry->rt_flags & (RTF_HOST|RTF_GATEWAY|RTF_DYNAMIC));
 311:         rt->rt_refcnt = 0;
 312:         rt->rt_use = 0;
 313:         rt->rt_ifp = ifa->ifa_ifp;
 314:         break;
 315:     }
 316: bad:
 317:     splx(s);
 318:     return (error);
 319: }
 320: 
 321: /*
 322:  * Set up a routing table entry, normally
 323:  * for an interface.
 324:  */
 325: rtinit(dst, gateway, cmd, flags)
 326:     struct sockaddr *dst, *gateway;
 327:     int cmd, flags;
 328: {
 329:     struct rtentry route;
 330: 
 331:     bzero((caddr_t)&route, sizeof (route));
 332:     route.rt_dst = *dst;
 333:     route.rt_gateway = *gateway;
 334:     route.rt_flags = flags;
 335:     (void) rtrequest(cmd, &route);
 336: }

Defined functions

Defined variables

Defined macros