1 /*- 2 * Copyright 1994, 1995 Massachusetts Institute of Technology 3 * 4 * Permission to use, copy, modify, and distribute this software and 5 * its documentation for any purpose and without fee is hereby 6 * granted, provided that both the above copyright notice and this 7 * permission notice appear in all copies, that both the above 8 * copyright notice and this permission notice appear in all 9 * supporting documentation, and that the name of M.I.T. not be used 10 * in advertising or publicity pertaining to distribution of the 11 * software without specific, written prior permission. M.I.T. makes 12 * no representations about the suitability of this software for any 13 * purpose. It is provided "as is" without express or implied 14 * warranty. 15 * 16 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS 17 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE, 18 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT 20 * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 23 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 25 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 26 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/cdefs.h> 31 #include <sys/param.h> 32 #include <sys/systm.h> 33 #include <sys/kernel.h> 34 #include <sys/sysctl.h> 35 #include <sys/socket.h> 36 #include <sys/mbuf.h> 37 38 #include <net/if.h> 39 #include <net/if_var.h> 40 #include <net/if_private.h> 41 #include <net/route.h> 42 #include <net/route/route_ctl.h> 43 #include <net/route/route_var.h> 44 #include <net/route/nhop.h> 45 #include <net/vnet.h> 46 47 #include <netinet/in.h> 48 #include <netinet/in_var.h> 49 #include <netinet/ip.h> 50 #include <netinet/ip_icmp.h> 51 #include <netinet/ip_var.h> 52 53 static int 54 rib4_set_nh_pfxflags(u_int fibnum, const struct sockaddr *addr, const struct sockaddr *mask, 55 struct nhop_object *nh) 56 { 57 const struct sockaddr_in *addr4 = (const struct sockaddr_in *)addr; 58 const struct sockaddr_in *mask4 = (const struct sockaddr_in *)mask; 59 bool is_broadcast = false; 60 61 if (mask == NULL) { 62 nhop_set_pxtype_flag(nh, NHF_HOST); 63 /* 64 * Backward compatibility: 65 * if the destination is broadcast, 66 * mark route as broadcast. 67 * This behavior was useful when route cloning 68 * was in place, so there was an explicit cloned 69 * route for every broadcasted address. 70 * Currently (2020-04) there is no kernel machinery 71 * to do route cloning, though someone might explicitly 72 * add these routes to support some cases with active-active 73 * load balancing. Given that, retain this support. 74 */ 75 if (in_broadcast(addr4->sin_addr, nh->nh_ifp)) 76 is_broadcast = true; 77 } else if (mask4->sin_addr.s_addr == 0) 78 nhop_set_pxtype_flag(nh, NHF_DEFAULT); 79 else 80 nhop_set_pxtype_flag(nh, 0); 81 82 nhop_set_broadcast(nh, is_broadcast); 83 84 return (0); 85 } 86 87 static int 88 rib4_augment_nh(u_int fibnum, struct nhop_object *nh) 89 { 90 /* 91 * Check route MTU: 92 * inherit interface MTU if not set or 93 * check if MTU is too large. 94 */ 95 if (nh->nh_mtu == 0) { 96 nh->nh_mtu = nh->nh_ifp->if_mtu; 97 } else if (nh->nh_mtu > nh->nh_ifp->if_mtu) 98 nh->nh_mtu = nh->nh_ifp->if_mtu; 99 100 /* Set nhop type to basic per-AF nhop */ 101 if (nhop_get_type(nh) == 0) { 102 uint16_t nh_type; 103 if (nh->nh_flags & NHF_GATEWAY) 104 nh_type = NH_TYPE_IPV4_ETHER_NHOP; 105 else 106 nh_type = NH_TYPE_IPV4_ETHER_RSLV; 107 108 nhop_set_type(nh, nh_type); 109 } 110 111 return (0); 112 } 113 114 /* 115 * Initialize our routing tree. 116 */ 117 struct rib_head * 118 in_inithead(uint32_t fibnum) 119 { 120 struct rib_head *rh; 121 122 rh = rt_table_init(32, AF_INET, fibnum); 123 if (rh == NULL) 124 return (NULL); 125 126 rh->rnh_set_nh_pfxflags = rib4_set_nh_pfxflags; 127 rh->rnh_augment_nh = rib4_augment_nh; 128 129 return (rh); 130 } 131 132 #ifdef VIMAGE 133 void 134 in_detachhead(struct rib_head *rh) 135 { 136 137 rt_table_destroy(rh); 138 } 139 #endif 140 141 /* 142 * This zaps old routes when the interface goes down or interface 143 * address is deleted. In the latter case, it deletes static routes 144 * that point to this address. If we don't do this, we may end up 145 * using the old address in the future. The ones we always want to 146 * get rid of are things like ARP entries, since the user might down 147 * the interface, walk over to a completely different network, and 148 * plug back in. 149 */ 150 struct in_ifadown_arg { 151 struct ifaddr *ifa; 152 int del; 153 }; 154 155 static int 156 in_ifadownkill(const struct rtentry *rt, const struct nhop_object *nh, 157 void *xap) 158 { 159 struct in_ifadown_arg *ap = xap; 160 161 if (nh->nh_ifa != ap->ifa) 162 return (0); 163 164 if ((nhop_get_rtflags(nh) & RTF_STATIC) != 0 && ap->del == 0) 165 return (0); 166 167 return (1); 168 } 169 170 void 171 in_ifadown(struct ifaddr *ifa, int delete) 172 { 173 struct in_ifadown_arg arg; 174 175 KASSERT(ifa->ifa_addr->sa_family == AF_INET, 176 ("%s: wrong family", __func__)); 177 178 arg.ifa = ifa; 179 arg.del = delete; 180 181 rib_foreach_table_walk_del(AF_INET, in_ifadownkill, &arg); 182 ifa->ifa_flags &= ~IFA_ROUTE; /* XXXlocking? */ 183 } 184