2.11BSD#431 - /usr/src/sys/net/route.c

   1: /*
   2:  * Copyright (c) 1980, 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 this notice is preserved and that due credit is given
   7:  * to the University of California at Berkeley. The name of the University
   8:  * may not be used to endorse or promote products derived from this
   9:  * software without specific prior written permission. This software
  10:  * is provided ``as is'' without express or implied warranty.
  11:  *
  12:  *	@(#)route.c	7.3 (Berkeley) 12/30/87
  13:  */
  14: 
  15: #include "param.h"
  16: #include "systm.h"
  17: #include "mbuf.h"
  18: #include "protosw.h"
  19: #include "socket.h"
  20: #include "user.h"
  21: #include "ioctl.h"
  22: #include "errno.h"
  23: 
  24: #include "if.h"
  25: #include "af.h"
  26: #include "route.h"
  27: 
  28: int rttrash;        /* routes not in table but not freed */
  29: struct  sockaddr wildcard;  /* zero valued cookie for wildcard searches */
  30: int rthashsize = RTHASHSIZ; /* for netstat, etc. */
  31: 
  32: /*
  33:  * Packet routing routines.
  34:  */
  35: rtalloc(ro)
  36:     register struct route *ro;
  37: {
  38:     register struct rtentry *rt;
  39:     register struct mbuf *m;
  40:     register u_int hash;
  41:     struct sockaddr *dst = &ro->ro_dst;
  42:     int (*match)(), doinghost, s;
  43:     struct afhash h;
  44:     u_int af = dst->sa_family;
  45:     struct mbuf **table;
  46: 
  47:     if (ro->ro_rt && ro->ro_rt->rt_ifp && (ro->ro_rt->rt_flags & RTF_UP))
  48:         return;              /* XXX */
  49:     if (af >= AF_MAX)
  50:         return;
  51:     (*afswitch[af].af_hash)(dst, &h);
  52:     match = afswitch[af].af_netmatch;
  53:     hash = h.afh_hosthash, table = rthost, doinghost = 1;
  54:     s = splnet();
  55: again:
  56:     for (m = table[RTHASHMOD(hash)]; m; m = m->m_next) {
  57:         rt = mtod(m, struct rtentry *);
  58:         if (rt->rt_hash != hash)
  59:             continue;
  60:         if ((rt->rt_flags & RTF_UP) == 0 ||
  61:             (rt->rt_ifp->if_flags & IFF_UP) == 0)
  62:             continue;
  63:         if (doinghost) {
  64:             if (bcmp((caddr_t)&rt->rt_dst, (caddr_t)dst,
  65:                 sizeof (*dst)))
  66:                 continue;
  67:         } else {
  68:             if (rt->rt_dst.sa_family != af ||
  69:                 !(*match)(&rt->rt_dst, dst))
  70:                 continue;
  71:         }
  72:         rt->rt_refcnt++;
  73:         splx(s);
  74:         if (dst == &wildcard)
  75:             rtstat.rts_wildcard++;
  76:         ro->ro_rt = rt;
  77:         return;
  78:     }
  79:     if (doinghost) {
  80:         doinghost = 0;
  81:         hash = h.afh_nethash, table = rtnet;
  82:         goto again;
  83:     }
  84:     /*
  85: 	 * Check for wildcard gateway, by convention network 0.
  86: 	 */
  87:     if (dst != &wildcard) {
  88:         dst = &wildcard, hash = 0;
  89:         goto again;
  90:     }
  91:     splx(s);
  92:     rtstat.rts_unreach++;
  93: }
  94: 
  95: rtfree(rt)
  96:     register struct rtentry *rt;
  97: {
  98: 
  99:     if (rt == 0)
 100:         panic("rtfree");
 101:     rt->rt_refcnt--;
 102:     if (rt->rt_refcnt == 0 && (rt->rt_flags&RTF_UP) == 0) {
 103:         rttrash--;
 104:         (void) m_free(dtom(rt));
 105:     }
 106: }
 107: 
 108: /*
 109:  * Force a routing table entry to the specified
 110:  * destination to go through the given gateway.
 111:  * Normally called as a result of a routing redirect
 112:  * message from the network layer.
 113:  *
 114:  * N.B.: must be called at splnet or higher
 115:  *
 116:  */
 117: rtredirect(dst, gateway, flags, src)
 118:     struct sockaddr *dst, *gateway, *src;
 119:     int flags;
 120: {
 121:     struct route ro;
 122:     register struct rtentry *rt;
 123: 
 124:     /* verify the gateway is directly reachable */
 125:     if (ifa_ifwithnet(gateway) == 0) {
 126:         rtstat.rts_badredirect++;
 127:         return;
 128:     }
 129:     ro.ro_dst = *dst;
 130:     ro.ro_rt = 0;
 131:     rtalloc(&ro);
 132:     rt = ro.ro_rt;
 133: #define equal(a1, a2) \
 134:     (bcmp((caddr_t)(a1), (caddr_t)(a2), sizeof(struct sockaddr)) == 0)
 135:     /*
 136: 	 * If the redirect isn't from our current router for this dst,
 137: 	 * it's either old or wrong.  If it redirects us to ourselves,
 138: 	 * we have a routing loop, perhaps as a result of an interface
 139: 	 * going down recently.
 140: 	 */
 141:     if ((rt && !equal(src, &rt->rt_gateway)) || ifa_ifwithaddr(gateway)) {
 142:         rtstat.rts_badredirect++;
 143:         if (rt)
 144:             rtfree(rt);
 145:         return;
 146:     }
 147:     /*
 148: 	 * Create a new entry if we just got back a wildcard entry
 149: 	 * or the the lookup failed.  This is necessary for hosts
 150: 	 * which use routing redirects generated by smart gateways
 151: 	 * to dynamically build the routing tables.
 152: 	 */
 153:     if (rt &&
 154:         (*afswitch[dst->sa_family].af_netmatch)(&wildcard, &rt->rt_dst)) {
 155:         rtfree(rt);
 156:         rt = 0;
 157:     }
 158:     if (rt == 0) {
 159:         rtinit(dst, gateway, (int)SIOCADDRT,
 160:             (flags & RTF_HOST) | RTF_GATEWAY | RTF_DYNAMIC);
 161:         rtstat.rts_dynamic++;
 162:         return;
 163:     }
 164:     /*
 165: 	 * Don't listen to the redirect if it's
 166: 	 * for a route to an interface.
 167: 	 */
 168:     if (rt->rt_flags & RTF_GATEWAY) {
 169:         if (((rt->rt_flags & RTF_HOST) == 0) && (flags & RTF_HOST)) {
 170:             /*
 171: 			 * Changing from route to net => route to host.
 172: 			 * Create new route, rather than smashing route to net.
 173: 			 */
 174:             rtinit(dst, gateway, (int)SIOCADDRT,
 175:                 flags | RTF_DYNAMIC);
 176:             rtstat.rts_dynamic++;
 177:         } else {
 178:             /*
 179: 			 * Smash the current notion of the gateway to
 180: 			 * this destination.
 181: 			 */
 182:             rt->rt_gateway = *gateway;
 183:             rt->rt_flags |= RTF_MODIFIED;
 184:             rtstat.rts_newgateway++;
 185:         }
 186:     } else
 187:         rtstat.rts_badredirect++;
 188:     rtfree(rt);
 189: }
 190: 
 191: /*
 192:  * Routing table ioctl interface.
 193:  */
 194: rtioctl(cmd, data)
 195:     int cmd;
 196:     caddr_t data;
 197: {
 198: 
 199:     if (cmd != SIOCADDRT && cmd != SIOCDELRT)
 200:         return (EINVAL);
 201:     if (!suser())
 202:         return (u.u_error);
 203:     return (rtrequest(cmd, (struct rtentry *)data));
 204: }
 205: 
 206: /*
 207:  * Carry out a request to change the routing table.  Called by
 208:  * interfaces at boot time to make their ``local routes'' known,
 209:  * for ioctl's, and as the result of routing redirects.
 210:  */
 211: rtrequest(req, entry)
 212:     int req;
 213:     register struct rtentry *entry;
 214: {
 215:     register struct mbuf *m, **mprev;
 216:     struct mbuf **mfirst;
 217:     register struct rtentry *rt;
 218:     struct afhash h;
 219:     int s, error = 0, (*match)();
 220:     u_int af;
 221:     u_int hash;
 222:     struct ifaddr *ifa;
 223:     struct ifaddr *ifa_ifwithdstaddr();
 224: 
 225:     af = entry->rt_dst.sa_family;
 226:     if (af >= AF_MAX)
 227:         return (EAFNOSUPPORT);
 228:     (*afswitch[af].af_hash)(&entry->rt_dst, &h);
 229:     if (entry->rt_flags & RTF_HOST) {
 230:         hash = h.afh_hosthash;
 231:         mprev = &rthost[RTHASHMOD(hash)];
 232:     } else {
 233:         hash = h.afh_nethash;
 234:         mprev = &rtnet[RTHASHMOD(hash)];
 235:     }
 236:     match = afswitch[af].af_netmatch;
 237:     s = splimp();
 238:     for (mfirst = mprev; m = *mprev; mprev = &m->m_next) {
 239:         rt = mtod(m, struct rtentry *);
 240:         if (rt->rt_hash != hash)
 241:             continue;
 242:         if (entry->rt_flags & RTF_HOST) {
 243:             if (!equal(&rt->rt_dst, &entry->rt_dst))
 244:                 continue;
 245:         } else {
 246:             if (rt->rt_dst.sa_family != entry->rt_dst.sa_family ||
 247:                 (*match)(&rt->rt_dst, &entry->rt_dst) == 0)
 248:                 continue;
 249:         }
 250:         if (equal(&rt->rt_gateway, &entry->rt_gateway))
 251:             break;
 252:     }
 253:     switch (req) {
 254: 
 255:     case SIOCDELRT:
 256:         if (m == 0) {
 257:             error = ESRCH;
 258:             goto bad;
 259:         }
 260:         *mprev = m->m_next;
 261:         if (rt->rt_refcnt > 0) {
 262:             rt->rt_flags &= ~RTF_UP;
 263:             rttrash++;
 264:             m->m_next = 0;
 265:         } else
 266:             (void) m_free(m);
 267:         break;
 268: 
 269:     case SIOCADDRT:
 270:         if (m) {
 271:             error = EEXIST;
 272:             goto bad;
 273:         }
 274:         if ((entry->rt_flags & RTF_GATEWAY) == 0) {
 275:             /*
 276: 			 * If we are adding a route to an interface,
 277: 			 * and the interface is a pt to pt link
 278: 			 * we should search for the destination
 279: 			 * as our clue to the interface.  Otherwise
 280: 			 * we can use the local address.
 281: 			 */
 282:             ifa = 0;
 283:             if (entry->rt_flags & RTF_HOST)
 284:                 ifa = ifa_ifwithdstaddr(&entry->rt_dst);
 285:             if (ifa == 0)
 286:                 ifa = ifa_ifwithaddr(&entry->rt_gateway);
 287:         } else {
 288:             /*
 289: 			 * If we are adding a route to a remote net
 290: 			 * or host, the gateway may still be on the
 291: 			 * other end of a pt to pt link.
 292: 			 */
 293:             ifa = ifa_ifwithdstaddr(&entry->rt_gateway);
 294:         }
 295:         if (ifa == 0) {
 296:             ifa = ifa_ifwithnet(&entry->rt_gateway);
 297:             if (ifa == 0) {
 298:                 error = ENETUNREACH;
 299:                 goto bad;
 300:             }
 301:         }
 302:         m = m_get(M_DONTWAIT, MT_RTABLE);
 303:         if (m == 0) {
 304:             error = ENOBUFS;
 305:             goto bad;
 306:         }
 307:         m->m_next = *mfirst;
 308:         *mfirst = m;
 309:         m->m_off = MMINOFF;
 310:         m->m_len = sizeof (struct rtentry);
 311:         rt = mtod(m, struct rtentry *);
 312:         rt->rt_hash = hash;
 313:         rt->rt_dst = entry->rt_dst;
 314:         rt->rt_gateway = entry->rt_gateway;
 315:         rt->rt_flags = RTF_UP |
 316:             (entry->rt_flags & (RTF_HOST|RTF_GATEWAY|RTF_DYNAMIC));
 317:         rt->rt_refcnt = 0;
 318:         rt->rt_use = 0;
 319:         rt->rt_ifp = ifa->ifa_ifp;
 320:         break;
 321:     }
 322: bad:
 323:     splx(s);
 324:     return (error);
 325: }
 326: 
 327: /*
 328:  * Set up a routing table entry, normally
 329:  * for an interface.
 330:  */
 331: rtinit(dst, gateway, cmd, flags)
 332:     struct sockaddr *dst, *gateway;
 333:     int cmd, flags;
 334: {
 335:     struct rtentry route;
 336: 
 337:     bzero((caddr_t)&route, sizeof (route));
 338:     route.rt_dst = *dst;
 339:     route.rt_gateway = *gateway;
 340:     route.rt_flags = flags;
 341:     (void) rtrequest(cmd, &route);
 342: }

Defined functions

Defined variables

Defined macros