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 __FBSDID("$FreeBSD$"); 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/kernel.h> 36 #include <sys/sysctl.h> 37 #include <sys/socket.h> 38 #include <sys/mbuf.h> 39 40 #include <net/if.h> 41 #include <net/if_var.h> 42 #include <net/route.h> 43 #include <net/route/route_ctl.h> 44 #include <net/route/route_var.h> 45 #include <net/route/nhop.h> 46 #include <net/vnet.h> 47 48 #include <netinet/in.h> 49 #include <netinet/in_var.h> 50 #include <netinet/ip.h> 51 #include <netinet/ip_icmp.h> 52 #include <netinet/ip_var.h> 53 54 static int 55 rib4_set_nh_pfxflags(u_int fibnum, const struct sockaddr *addr, const struct sockaddr *mask, 56 struct nhop_object *nh) 57 { 58 const struct sockaddr_in *addr4 = (const struct sockaddr_in *)addr; 59 const struct sockaddr_in *mask4 = (const struct sockaddr_in *)mask; 60 bool is_broadcast = false; 61 62 if (mask == NULL) { 63 nhop_set_pxtype_flag(nh, NHF_HOST); 64 /* 65 * Backward compatibility: 66 * if the destination is broadcast, 67 * mark route as broadcast. 68 * This behavior was useful when route cloning 69 * was in place, so there was an explicit cloned 70 * route for every broadcasted address. 71 * Currently (2020-04) there is no kernel machinery 72 * to do route cloning, though someone might explicitly 73 * add these routes to support some cases with active-active 74 * load balancing. Given that, retain this support. 75 */ 76 if (in_broadcast(addr4->sin_addr, nh->nh_ifp)) 77 is_broadcast = true; 78 } else if (mask4->sin_addr.s_addr == 0) 79 nhop_set_pxtype_flag(nh, NHF_DEFAULT); 80 else 81 nhop_set_pxtype_flag(nh, 0); 82 83 nhop_set_broadcast(nh, is_broadcast); 84 85 return (0); 86 } 87 88 static int 89 rib4_augment_nh(u_int fibnum, struct nhop_object *nh) 90 { 91 /* 92 * Check route MTU: 93 * inherit interface MTU if not set or 94 * check if MTU is too large. 95 */ 96 if (nh->nh_mtu == 0) { 97 nh->nh_mtu = nh->nh_ifp->if_mtu; 98 } else if (nh->nh_mtu > nh->nh_ifp->if_mtu) 99 nh->nh_mtu = nh->nh_ifp->if_mtu; 100 101 /* Set nhop type to basic per-AF nhop */ 102 if (nhop_get_type(nh) == 0) { 103 uint16_t nh_type; 104 if (nh->nh_flags & NHF_GATEWAY) 105 nh_type = NH_TYPE_IPV4_ETHER_NHOP; 106 else 107 nh_type = NH_TYPE_IPV4_ETHER_RSLV; 108 109 nhop_set_type(nh, nh_type); 110 } 111 112 return (0); 113 } 114 115 /* 116 * Initialize our routing tree. 117 */ 118 struct rib_head * 119 in_inithead(uint32_t fibnum) 120 { 121 struct rib_head *rh; 122 123 rh = rt_table_init(32, AF_INET, fibnum); 124 if (rh == NULL) 125 return (NULL); 126 127 rh->rnh_set_nh_pfxflags = rib4_set_nh_pfxflags; 128 rh->rnh_augment_nh = rib4_augment_nh; 129 130 return (rh); 131 } 132 133 #ifdef VIMAGE 134 void 135 in_detachhead(struct rib_head *rh) 136 { 137 138 rt_table_destroy(rh); 139 } 140 #endif 141 142 /* 143 * This zaps old routes when the interface goes down or interface 144 * address is deleted. In the latter case, it deletes static routes 145 * that point to this address. If we don't do this, we may end up 146 * using the old address in the future. The ones we always want to 147 * get rid of are things like ARP entries, since the user might down 148 * the interface, walk over to a completely different network, and 149 * plug back in. 150 */ 151 struct in_ifadown_arg { 152 struct ifaddr *ifa; 153 int del; 154 }; 155 156 static int 157 in_ifadownkill(const struct rtentry *rt, const struct nhop_object *nh, 158 void *xap) 159 { 160 struct in_ifadown_arg *ap = xap; 161 162 if (nh->nh_ifa != ap->ifa) 163 return (0); 164 165 if ((nhop_get_rtflags(nh) & RTF_STATIC) != 0 && ap->del == 0) 166 return (0); 167 168 return (1); 169 } 170 171 void 172 in_ifadown(struct ifaddr *ifa, int delete) 173 { 174 struct in_ifadown_arg arg; 175 176 KASSERT(ifa->ifa_addr->sa_family == AF_INET, 177 ("%s: wrong family", __func__)); 178 179 arg.ifa = ifa; 180 arg.del = delete; 181 182 rib_foreach_table_walk_del(AF_INET, in_ifadownkill, &arg); 183 ifa->ifa_flags &= ~IFA_ROUTE; /* XXXlocking? */ 184 } 185