1 /* route.c 4.21 83/06/12 */ 2 3 #include "../h/param.h" 4 #include "../h/systm.h" 5 #include "../h/mbuf.h" 6 #include "../h/protosw.h" 7 #include "../h/socket.h" 8 #include "../h/dir.h" 9 #include "../h/user.h" 10 #include "../h/ioctl.h" 11 #include "../h/errno.h" 12 13 #include "../net/if.h" 14 #include "../net/af.h" 15 #include "../net/route.h" 16 17 int rttrash; /* routes not in table but not freed */ 18 struct sockaddr wildcard; /* zero valued cookie for wildcard searches */ 19 20 /* 21 * Packet routing routines. 22 */ 23 rtalloc(ro) 24 register struct route *ro; 25 { 26 register struct rtentry *rt; 27 register struct mbuf *m; 28 register unsigned hash; 29 struct sockaddr *dst = &ro->ro_dst; 30 int (*match)(), doinghost; 31 struct afhash h; 32 u_int af = dst->sa_family; 33 struct rtentry *rtmin; 34 struct mbuf **table; 35 36 if (ro->ro_rt && ro->ro_rt->rt_ifp) /* XXX */ 37 return; 38 if (af >= AF_MAX) 39 return; 40 (*afswitch[af].af_hash)(dst, &h); 41 rtmin = 0; 42 match = afswitch[af].af_netmatch; 43 hash = h.afh_hosthash, table = rthost, doinghost = 1; 44 again: 45 for (m = table[hash % RTHASHSIZ]; m; m = m->m_next) { 46 rt = mtod(m, struct rtentry *); 47 if (rt->rt_hash != hash) 48 continue; 49 if ((rt->rt_flags & RTF_UP) == 0 || 50 (rt->rt_ifp->if_flags & IFF_UP) == 0) 51 continue; 52 if (doinghost) { 53 if (bcmp((caddr_t)&rt->rt_dst, (caddr_t)dst, 54 sizeof (*dst))) 55 continue; 56 } else { 57 if (rt->rt_dst.sa_family != af || 58 !(*match)(&rt->rt_dst, dst)) 59 continue; 60 } 61 if (rtmin == 0 || rt->rt_use < rtmin->rt_use) 62 rtmin = rt; 63 } 64 if (rtmin == 0 && doinghost) { 65 doinghost = 0; 66 hash = h.afh_nethash, table = rtnet; 67 goto again; 68 } 69 /* 70 * Check for wildcard gateway, by convention network 0. 71 */ 72 if (rtmin == 0 && dst != &wildcard) { 73 dst = &wildcard, hash = 0; 74 goto again; 75 } 76 ro->ro_rt = rtmin; 77 if (rtmin == 0) { 78 rtstat.rts_unreach++; 79 return; 80 } 81 rtmin->rt_refcnt++; 82 if (dst == &wildcard) 83 rtstat.rts_wildcard++; 84 } 85 86 rtfree(rt) 87 register struct rtentry *rt; 88 { 89 90 if (rt == 0) 91 panic("rtfree"); 92 rt->rt_refcnt--; 93 if (rt->rt_refcnt == 0 && (rt->rt_flags&RTF_UP) == 0) { 94 rttrash--; 95 (void) m_free(dtom(rt)); 96 } 97 } 98 99 /* 100 * Force a routing table entry to the specified 101 * destination to go through the given gateway. 102 * Normally called as a result of a routing redirect 103 * message from the network layer. 104 * 105 * N.B.: must be called at splnet or higher 106 * 107 * Should notify all parties with a reference to 108 * the route that it's changed (so, for instance, 109 * current round trip time estimates could be flushed), 110 * but we have no back pointers at the moment. 111 */ 112 rtredirect(dst, gateway) 113 struct sockaddr *dst, *gateway; 114 { 115 struct route ro; 116 register struct rtentry *rt; 117 118 /* verify the gateway is directly reachable */ 119 if (if_ifwithnet(gateway) == 0) { 120 rtstat.rts_badredirect++; 121 return; 122 } 123 ro.ro_dst = *dst; 124 ro.ro_rt = 0; 125 rtalloc(&ro); 126 rt = ro.ro_rt; 127 /* 128 * Create a new entry if the lookup failed. 129 * This is necessary for hosts which use routing 130 * redirects generated by smart gateways to dynamically 131 * build the routing tables. 132 */ 133 if (rt == 0) { 134 rtinit(dst, gateway, RTF_GATEWAY); 135 rtstat.rts_dynamic++; 136 return; 137 } 138 /* 139 * Don't listen to the redirect if it's 140 * for a route to an interface. 141 */ 142 if (rt->rt_flags & RTF_GATEWAY) { 143 /* 144 * Smash the current notion of the gateway to 145 * this destination. This is probably not right, 146 * as it's conceivable a flurry of redirects could 147 * cause the gateway value to fluctuate wildly during 148 * dynamic routing reconfiguration. 149 */ 150 rt->rt_gateway = *gateway; 151 rtfree(rt); 152 rtstat.rts_newgateway++; 153 return; 154 } 155 } 156 157 /* 158 * Routing table ioctl interface. 159 */ 160 rtioctl(cmd, data) 161 int cmd; 162 caddr_t data; 163 { 164 165 if (cmd != SIOCADDRT && cmd != SIOCDELRT) 166 return (EINVAL); 167 if (!suser()) 168 return (u.u_error); 169 return (rtrequest(cmd, (struct rtentry *)data)); 170 } 171 172 /* 173 * Carry out a request to change the routing table. Called by 174 * interfaces at boot time to make their ``local routes'' known, 175 * for ioctl's, and as the result of routing redirects. 176 */ 177 rtrequest(req, entry) 178 int req; 179 register struct rtentry *entry; 180 { 181 register struct mbuf *m, **mprev; 182 register struct rtentry *rt; 183 struct afhash h; 184 int s, error = 0, hash, (*match)(); 185 u_int af; 186 struct ifnet *ifp; 187 188 af = entry->rt_dst.sa_family; 189 if (af >= AF_MAX) 190 return (EAFNOSUPPORT); 191 (*afswitch[af].af_hash)(&entry->rt_dst, &h); 192 if (entry->rt_flags & RTF_HOST) { 193 hash = h.afh_hosthash; 194 mprev = &rthost[hash % RTHASHSIZ]; 195 } else { 196 hash = h.afh_nethash; 197 mprev = &rtnet[hash % RTHASHSIZ]; 198 } 199 match = afswitch[af].af_netmatch; 200 s = splimp(); 201 for (; m = *mprev; mprev = &m->m_next) { 202 rt = mtod(m, struct rtentry *); 203 if (rt->rt_hash != hash) 204 continue; 205 if (entry->rt_flags & RTF_HOST) { 206 #define equal(a1, a2) \ 207 (bcmp((caddr_t)(a1), (caddr_t)(a2), sizeof (struct sockaddr)) == 0) 208 if (!equal(&rt->rt_dst, &entry->rt_dst)) 209 continue; 210 } else { 211 if (rt->rt_dst.sa_family != entry->rt_dst.sa_family || 212 (*match)(&rt->rt_dst, &entry->rt_dst) == 0) 213 continue; 214 } 215 if (equal(&rt->rt_gateway, &entry->rt_gateway)) 216 break; 217 } 218 switch (req) { 219 220 case SIOCDELRT: 221 if (m == 0) { 222 error = ESRCH; 223 goto bad; 224 } 225 *mprev = m->m_next; 226 if (rt->rt_refcnt > 0) { 227 rt->rt_flags &= ~RTF_UP; 228 rttrash++; 229 m->m_next = 0; 230 } else 231 (void) m_free(m); 232 break; 233 234 case SIOCADDRT: 235 if (m) { 236 error = EEXIST; 237 goto bad; 238 } 239 ifp = if_ifwithaddr(&entry->rt_gateway); 240 if (ifp == 0) { 241 ifp = if_ifwithnet(&entry->rt_gateway); 242 if (ifp == 0) { 243 error = ENETUNREACH; 244 goto bad; 245 } 246 } 247 m = m_get(M_DONTWAIT, MT_RTABLE); 248 if (m == 0) { 249 error = ENOBUFS; 250 goto bad; 251 } 252 *mprev = m; 253 m->m_off = MMINOFF; 254 m->m_len = sizeof (struct rtentry); 255 rt = mtod(m, struct rtentry *); 256 rt->rt_hash = hash; 257 rt->rt_dst = entry->rt_dst; 258 rt->rt_gateway = entry->rt_gateway; 259 rt->rt_flags = 260 RTF_UP | (entry->rt_flags & (RTF_HOST|RTF_GATEWAY)); 261 rt->rt_refcnt = 0; 262 rt->rt_use = 0; 263 rt->rt_ifp = ifp; 264 break; 265 } 266 bad: 267 splx(s); 268 return (error); 269 } 270 271 /* 272 * Set up a routing table entry, normally 273 * for an interface. 274 */ 275 rtinit(dst, gateway, flags) 276 struct sockaddr *dst, *gateway; 277 int flags; 278 { 279 struct rtentry route; 280 int cmd; 281 282 if (flags == -1) { 283 cmd = (int)SIOCDELRT; 284 flags = 0; 285 } else { 286 cmd = (int)SIOCADDRT; 287 } 288 bzero((caddr_t)&route, sizeof (route)); 289 route.rt_dst = *dst; 290 route.rt_gateway = *gateway; 291 route.rt_flags = flags; 292 (void) rtrequest(cmd, &route); 293 } 294