1 /* route.c 4.18 83/03/15 */ 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/ioctl.h" 9 #include "../h/errno.h" 10 11 #include "../net/if.h" 12 #include "../net/af.h" 13 #include "../net/route.h" 14 15 int rttrash; /* routes not in table but not freed */ 16 /* 17 * Packet routing routines. 18 */ 19 rtalloc(ro) 20 register struct route *ro; 21 { 22 register struct rtentry *rt, *rtmin; 23 register struct mbuf *m; 24 register unsigned hash; 25 register int (*match)(); 26 struct afhash h; 27 struct sockaddr *dst = &ro->ro_dst; 28 int af = dst->sa_family; 29 30 if (ro->ro_rt && ro->ro_rt->rt_ifp) /* XXX */ 31 return; 32 if (af >= AF_MAX) 33 return; 34 (*afswitch[af].af_hash)(dst, &h); 35 rtmin = 0, hash = h.afh_hosthash; 36 for (m = rthost[hash % RTHASHSIZ]; m; m = m->m_next) { 37 rt = mtod(m, struct rtentry *); 38 if (rt->rt_hash != hash) 39 continue; 40 if ((rt->rt_flags & RTF_UP) == 0 || 41 (rt->rt_ifp->if_flags & IFF_UP) == 0) 42 continue; 43 if (bcmp((caddr_t)&rt->rt_dst, (caddr_t)dst, sizeof (*dst))) 44 continue; 45 if (rtmin == 0 || rt->rt_use < rtmin->rt_use) 46 rtmin = rt; 47 } 48 if (rtmin) 49 goto found; 50 51 hash = h.afh_nethash; 52 match = afswitch[af].af_netmatch; 53 for (m = rtnet[hash % RTHASHSIZ]; m; m = m->m_next) { 54 rt = mtod(m, struct rtentry *); 55 if (rt->rt_hash != hash) 56 continue; 57 if ((rt->rt_flags & RTF_UP) == 0 || 58 (rt->rt_ifp->if_flags & IFF_UP) == 0) 59 continue; 60 if (rt->rt_dst.sa_family != af || !(*match)(&rt->rt_dst, dst)) 61 continue; 62 if (rtmin == 0 || rt->rt_use < rtmin->rt_use) 63 rtmin = rt; 64 } 65 found: 66 ro->ro_rt = rtmin; 67 if (rtmin) 68 rtmin->rt_refcnt++; 69 } 70 71 rtfree(rt) 72 register struct rtentry *rt; 73 { 74 75 if (rt == 0) 76 panic("rtfree"); 77 rt->rt_refcnt--; 78 if (rt->rt_refcnt == 0 && (rt->rt_flags&RTF_UP) == 0) { 79 rttrash--; 80 (void) m_free(dtom(rt)); 81 } 82 } 83 84 /* 85 * Force a routing table entry to the specified 86 * destination to go through the given gateway. 87 * Normally called as a result of a routing redirect 88 * message from the network layer. 89 * 90 * N.B.: must be called at splnet or higher 91 * 92 * Should notify all parties with a reference to 93 * the route that it's changed (so, for instance, 94 * round trip time estimates may be recalculated), 95 * but we have no back pointers at the moment. 96 */ 97 rtredirect(dst, gateway) 98 struct sockaddr *dst, *gateway; 99 { 100 struct route ro; 101 register struct rtentry *rt; 102 103 /* verify the gateway is directly reachable */ 104 if (if_ifwithnet(gateway) == 0) 105 return; 106 ro.ro_dst = *dst; 107 ro.ro_rt = NULL; 108 rtalloc(&ro); 109 rt = ro.ro_rt; 110 /* 111 * Don't listen to the redirect if it's 112 * for a route to an interface. 113 * 114 * Should probably create a new entry when 115 * the lookup fails. This will be necessary 116 * when wildcard routes are added. 117 */ 118 if (rt == NULL || (rt->rt_flags & RTF_GATEWAY) == 0) 119 return; 120 rt->rt_gateway = *gateway; 121 rtfree(rt); 122 } 123 124 /* 125 * Carry out a request to change the routing table. Called by 126 * interfaces at boot time to make their ``local routes'' known 127 * and for ioctl's. 128 */ 129 rtrequest(req, entry) 130 int req; 131 register struct rtentry *entry; 132 { 133 register struct mbuf *m, **mprev; 134 register struct rtentry *rt; 135 struct afhash h; 136 int af, s, error = 0, hash, (*match)(); 137 struct ifnet *ifp; 138 139 af = entry->rt_dst.sa_family; 140 if (af >= AF_MAX) 141 return (EAFNOSUPPORT); 142 (*afswitch[af].af_hash)(&entry->rt_dst, &h); 143 if (entry->rt_flags & RTF_HOST) { 144 hash = h.afh_hosthash; 145 mprev = &rthost[hash % RTHASHSIZ]; 146 } else { 147 hash = h.afh_nethash; 148 mprev = &rtnet[hash % RTHASHSIZ]; 149 } 150 match = afswitch[af].af_netmatch; 151 s = splimp(); 152 for (; m = *mprev; mprev = &m->m_next) { 153 rt = mtod(m, struct rtentry *); 154 if (rt->rt_hash != hash) 155 continue; 156 if (entry->rt_flags & RTF_HOST) { 157 #define equal(a1, a2) \ 158 (bcmp((caddr_t)(a1), (caddr_t)(a2), sizeof (struct sockaddr)) == 0) 159 if (!equal(&rt->rt_dst, &entry->rt_dst)) 160 continue; 161 } else { 162 if (rt->rt_dst.sa_family != entry->rt_dst.sa_family || 163 (*match)(&rt->rt_dst, &entry->rt_dst) == 0) 164 continue; 165 } 166 if (equal(&rt->rt_gateway, &entry->rt_gateway)) 167 break; 168 } 169 switch (req) { 170 171 case SIOCDELRT: 172 if (m == 0) { 173 error = ESRCH; 174 goto bad; 175 } 176 *mprev = m->m_next; 177 if (rt->rt_refcnt > 0) { 178 rt->rt_flags &= ~RTF_UP; 179 rttrash++; 180 m->m_next = 0; 181 } else 182 (void) m_free(m); 183 break; 184 185 case SIOCADDRT: 186 if (m) { 187 error = EEXIST; 188 goto bad; 189 } 190 ifp = if_ifwithaddr(&entry->rt_gateway); 191 if (ifp == 0) { 192 ifp = if_ifwithnet(&entry->rt_gateway); 193 if (ifp == 0) { 194 error = ENETUNREACH; 195 goto bad; 196 } 197 } 198 m = m_get(M_DONTWAIT, MT_RTABLE); 199 if (m == 0) { 200 error = ENOBUFS; 201 goto bad; 202 } 203 *mprev = m; 204 m->m_off = MMINOFF; 205 m->m_len = sizeof (struct rtentry); 206 rt = mtod(m, struct rtentry *); 207 rt->rt_hash = hash; 208 rt->rt_dst = entry->rt_dst; 209 rt->rt_gateway = entry->rt_gateway; 210 rt->rt_flags = 211 RTF_UP | (entry->rt_flags & (RTF_HOST|RTF_GATEWAY)); 212 rt->rt_refcnt = 0; 213 rt->rt_use = 0; 214 rt->rt_ifp = ifp; 215 break; 216 } 217 bad: 218 splx(s); 219 return (error); 220 } 221 222 /* 223 * Set up a routing table entry, normally 224 * for an interface. 225 */ 226 rtinit(dst, gateway, flags) 227 struct sockaddr *dst, *gateway; 228 int flags; 229 { 230 struct rtentry route; 231 int cmd; 232 233 if (flags == -1) { 234 cmd = (int)SIOCDELRT; 235 flags = 0; 236 } else { 237 cmd = (int)SIOCADDRT; 238 } 239 bzero((caddr_t)&route, sizeof (route)); 240 route.rt_dst = *dst; 241 route.rt_gateway = *gateway; 242 route.rt_flags = flags; 243 (void) rtrequest(cmd, &route); 244 } 245