1/* $KAME: radix_mpath.c,v 1.17 2004/11/08 10:29:39 itojun Exp $ */ 2 3/* 4 * Copyright (C) 2001 WIDE Project. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the project nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * THE AUTHORS DO NOT GUARANTEE THAT THIS SOFTWARE DOES NOT INFRINGE 31 * ANY OTHERS' INTELLECTUAL PROPERTIES. IN NO EVENT SHALL THE AUTHORS 32 * BE LIABLE FOR ANY INFRINGEMENT OF ANY OTHERS' INTELLECTUAL 33 * PROPERTIES. 34 */ 35 36#include <sys/cdefs.h> 37__FBSDID("$FreeBSD$"); 38 39#include "opt_inet.h" 40#include "opt_inet6.h" 41 42#include <sys/param.h> 43#include <sys/systm.h> 44#include <sys/malloc.h> 45#include <sys/socket.h> 46#include <sys/domain.h> 47#include <sys/syslog.h> 48#include <net/radix.h> 49#include <net/radix_mpath.h> 50#include <net/route.h> 51#include <net/route_var.h> 52#include <net/if.h> 53#include <net/if_var.h> 54 55/* 56 * give some jitter to hash, to avoid synchronization between routers 57 */ 58static uint32_t hashjitter; 59 60int 61rt_mpath_capable(struct rib_head *rnh) 62{ 63 64 return rnh->rnh_multipath; 65} 66 67int 68rn_mpath_capable(struct radix_head *rh) 69{ 70 71 return (rt_mpath_capable((struct rib_head *)rh)); 72} 73 74struct radix_node * 75rn_mpath_next(struct radix_node *rn) 76{ 77 struct radix_node *next; 78 79 if (!rn->rn_dupedkey) 80 return NULL; 81 next = rn->rn_dupedkey; 82 if (rn->rn_mask == next->rn_mask) 83 return next; 84 else 85 return NULL; 86} 87 88uint32_t 89rn_mpath_count(struct radix_node *rn) 90{ 91 uint32_t i = 0; 92 struct rtentry *rt; 93 94 while (rn != NULL) { 95 rt = (struct rtentry *)rn; 96 i += rt->rt_weight; 97 rn = rn_mpath_next(rn); 98 } 99 return (i); 100} 101 102struct rtentry * 103rt_mpath_matchgate(struct rtentry *rt, struct sockaddr *gate) 104{ 105 struct radix_node *rn; 106 107 if (!gate || !rt->rt_gateway) 108 return NULL; 109 110 /* beyond here, we use rn as the master copy */ 111 rn = (struct radix_node *)rt; 112 do { 113 rt = (struct rtentry *)rn; 114 /* 115 * we are removing an address alias that has 116 * the same prefix as another address 117 * we need to compare the interface address because 118 * rt_gateway is a special sockadd_dl structure 119 */ 120 if (rt->rt_gateway->sa_family == AF_LINK) { 121 if (!memcmp(rt->rt_ifa->ifa_addr, gate, gate->sa_len)) 122 break; 123 } 124 125 /* 126 * Check for other options: 127 * 1) Routes with 'real' IPv4/IPv6 gateway 128 * 2) Loopback host routes (another AF_LINK/sockadd_dl check) 129 * */ 130 if (rt->rt_gateway->sa_len == gate->sa_len && 131 !memcmp(rt->rt_gateway, gate, gate->sa_len)) 132 break; 133 } while ((rn = rn_mpath_next(rn)) != NULL); 134 135 return (struct rtentry *)rn; 136} 137 138/* 139 * go through the chain and unlink "rt" from the list 140 * the caller will free "rt" 141 */ 142int 143rt_mpath_deldup(struct rtentry *headrt, struct rtentry *rt) 144{ 145 struct radix_node *t, *tt; 146 147 if (!headrt || !rt) 148 return (0); 149 t = (struct radix_node *)headrt; 150 tt = rn_mpath_next(t); 151 while (tt) { 152 if (tt == (struct radix_node *)rt) { 153 t->rn_dupedkey = tt->rn_dupedkey; 154 tt->rn_dupedkey = NULL; 155 tt->rn_flags &= ~RNF_ACTIVE; 156 tt[1].rn_flags &= ~RNF_ACTIVE; 157 return (1); 158 } 159 t = tt; 160 tt = rn_mpath_next((struct radix_node *)t); 161 } 162 return (0); 163} 164 165/* 166 * check if we have the same key/mask/gateway on the table already. 167 * Assume @rt rt_key host bits are cleared according to @netmask 168 */ 169int 170rt_mpath_conflict(struct rib_head *rnh, struct rtentry *rt, 171 struct sockaddr *netmask) 172{ 173 struct radix_node *rn, *rn1; 174 struct rtentry *rt1; 175 176 rn = (struct radix_node *)rt; 177 rn1 = rnh->rnh_lookup(rt_key(rt), netmask, &rnh->head); 178 if (!rn1 || rn1->rn_flags & RNF_ROOT) 179 return (0); 180 181 /* key/mask are the same. compare gateway for all multipaths */ 182 do { 183 rt1 = (struct rtentry *)rn1; 184 185 /* sanity: no use in comparing the same thing */ 186 if (rn1 == rn) 187 continue; 188 189 if (rt1->rt_gateway->sa_family == AF_LINK) { 190 if (rt1->rt_ifa->ifa_addr->sa_len != rt->rt_ifa->ifa_addr->sa_len || 191 bcmp(rt1->rt_ifa->ifa_addr, rt->rt_ifa->ifa_addr, 192 rt1->rt_ifa->ifa_addr->sa_len)) 193 continue; 194 } else { 195 if (rt1->rt_gateway->sa_len != rt->rt_gateway->sa_len || 196 bcmp(rt1->rt_gateway, rt->rt_gateway, 197 rt1->rt_gateway->sa_len)) 198 continue; 199 } 200 201 /* all key/mask/gateway are the same. conflicting entry. */ 202 return (EEXIST); 203 } while ((rn1 = rn_mpath_next(rn1)) != NULL); 204 205 return (0); 206} 207 208static struct rtentry * 209rt_mpath_selectrte(struct rtentry *rte, uint32_t hash) 210{ 211 struct radix_node *rn0, *rn; 212 uint32_t total_weight; 213 struct rtentry *rt; 214 int64_t weight; 215 216 /* beyond here, we use rn as the master copy */ 217 rn0 = rn = (struct radix_node *)rte; 218 rt = rte; 219 220 /* gw selection by Modulo-N Hash (RFC2991) XXX need improvement? */ 221 total_weight = rn_mpath_count(rn0); 222 hash += hashjitter; 223 hash %= total_weight; 224 for (weight = abs((int32_t)hash); 225 rt != NULL && weight >= rt->rt_weight; 226 weight -= (rt == NULL) ? 0 : rt->rt_weight) { 227 228 /* stay within the multipath routes */ 229 if (rn->rn_dupedkey && rn->rn_mask != rn->rn_dupedkey->rn_mask) 230 break; 231 rn = rn->rn_dupedkey; 232 rt = (struct rtentry *)rn; 233 } 234 235 return (rt); 236} 237 238struct rtentry * 239rt_mpath_select(struct rtentry *rte, uint32_t hash) 240{ 241 if (rn_mpath_next((struct radix_node *)rte) == NULL) 242 return (rte); 243 244 return (rt_mpath_selectrte(rte, hash)); 245} 246 247void 248rtalloc_mpath_fib(struct route *ro, uint32_t hash, u_int fibnum) 249{ 250 struct rtentry *rt; 251 252 /* 253 * XXX we don't attempt to lookup cached route again; what should 254 * be done for sendto(3) case? 255 */ 256 if (ro->ro_rt && ro->ro_rt->rt_ifp && (ro->ro_rt->rt_flags & RTF_UP) 257 && RT_LINK_IS_UP(ro->ro_rt->rt_ifp)) 258 return; 259 ro->ro_rt = rtalloc1_fib(&ro->ro_dst, 1, 0, fibnum); 260 261 /* if the route does not exist or it is not multipath, don't care */ 262 if (ro->ro_rt == NULL) 263 return; 264 if (rn_mpath_next((struct radix_node *)ro->ro_rt) == NULL) { 265 RT_UNLOCK(ro->ro_rt); 266 return; 267 } 268 269 rt = rt_mpath_selectrte(ro->ro_rt, hash); 270 /* XXX try filling rt_gwroute and avoid unreachable gw */ 271 272 /* gw selection has failed - there must be only zero weight routes */ 273 if (!rt) { 274 RT_UNLOCK(ro->ro_rt); 275 ro->ro_rt = NULL; 276 return; 277 } 278 if (ro->ro_rt != rt) { 279 RTFREE_LOCKED(ro->ro_rt); 280 ro->ro_rt = rt; 281 RT_LOCK(ro->ro_rt); 282 RT_ADDREF(ro->ro_rt); 283 284 } 285 RT_UNLOCK(ro->ro_rt); 286} 287 288extern int in6_inithead(void **head, int off); 289extern int in_inithead(void **head, int off); 290 291#ifdef INET 292int 293rn4_mpath_inithead(void **head, int off) 294{ 295 struct rib_head *rnh; 296 297 hashjitter = arc4random(); 298 if (in_inithead(head, off) == 1) { 299 rnh = (struct rib_head *)*head; 300 rnh->rnh_multipath = 1; 301 return 1; 302 } else 303 return 0; 304} 305#endif 306 307#ifdef INET6 308int 309rn6_mpath_inithead(void **head, int off) 310{ 311 struct rib_head *rnh; 312 313 hashjitter = arc4random(); 314 if (in6_inithead(head, off) == 1) { 315 rnh = (struct rib_head *)*head; 316 rnh->rnh_multipath = 1; 317 return 1; 318 } else 319 return 0; 320} 321 322#endif 323