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/if_private.h> 43 #include <net/route.h> 44 #include <net/route/route_ctl.h> 45 #include <net/route/route_var.h> 46 #include <net/route/nhop.h> 47 #include <net/vnet.h> 48 49 #include <netinet/in.h> 50 #include <netinet/in_var.h> 51 #include <netinet/ip.h> 52 #include <netinet/ip_icmp.h> 53 #include <netinet/ip_var.h> 54 55 static int 56 rib4_set_nh_pfxflags(u_int fibnum, const struct sockaddr *addr, const struct sockaddr *mask, 57 struct nhop_object *nh) 58 { 59 const struct sockaddr_in *addr4 = (const struct sockaddr_in *)addr; 60 const struct sockaddr_in *mask4 = (const struct sockaddr_in *)mask; 61 bool is_broadcast = false; 62 63 if (mask == NULL) { 64 nhop_set_pxtype_flag(nh, NHF_HOST); 65 /* 66 * Backward compatibility: 67 * if the destination is broadcast, 68 * mark route as broadcast. 69 * This behavior was useful when route cloning 70 * was in place, so there was an explicit cloned 71 * route for every broadcasted address. 72 * Currently (2020-04) there is no kernel machinery 73 * to do route cloning, though someone might explicitly 74 * add these routes to support some cases with active-active 75 * load balancing. Given that, retain this support. 76 */ 77 if (in_broadcast(addr4->sin_addr, nh->nh_ifp)) 78 is_broadcast = true; 79 } else if (mask4->sin_addr.s_addr == 0) 80 nhop_set_pxtype_flag(nh, NHF_DEFAULT); 81 else 82 nhop_set_pxtype_flag(nh, 0); 83 84 nhop_set_broadcast(nh, is_broadcast); 85 86 return (0); 87 } 88 89 static int 90 rib4_augment_nh(u_int fibnum, struct nhop_object *nh) 91 { 92 /* 93 * Check route MTU: 94 * inherit interface MTU if not set or 95 * check if MTU is too large. 96 */ 97 if (nh->nh_mtu == 0) { 98 nh->nh_mtu = nh->nh_ifp->if_mtu; 99 } else if (nh->nh_mtu > nh->nh_ifp->if_mtu) 100 nh->nh_mtu = nh->nh_ifp->if_mtu; 101 102 /* Set nhop type to basic per-AF nhop */ 103 if (nhop_get_type(nh) == 0) { 104 uint16_t nh_type; 105 if (nh->nh_flags & NHF_GATEWAY) 106 nh_type = NH_TYPE_IPV4_ETHER_NHOP; 107 else 108 nh_type = NH_TYPE_IPV4_ETHER_RSLV; 109 110 nhop_set_type(nh, nh_type); 111 } 112 113 return (0); 114 } 115 116 /* 117 * Initialize our routing tree. 118 */ 119 struct rib_head * 120 in_inithead(uint32_t fibnum) 121 { 122 struct rib_head *rh; 123 124 rh = rt_table_init(32, AF_INET, fibnum); 125 if (rh == NULL) 126 return (NULL); 127 128 rh->rnh_set_nh_pfxflags = rib4_set_nh_pfxflags; 129 rh->rnh_augment_nh = rib4_augment_nh; 130 131 return (rh); 132 } 133 134 #ifdef VIMAGE 135 void 136 in_detachhead(struct rib_head *rh) 137 { 138 139 rt_table_destroy(rh); 140 } 141 #endif 142 143 /* 144 * This zaps old routes when the interface goes down or interface 145 * address is deleted. In the latter case, it deletes static routes 146 * that point to this address. If we don't do this, we may end up 147 * using the old address in the future. The ones we always want to 148 * get rid of are things like ARP entries, since the user might down 149 * the interface, walk over to a completely different network, and 150 * plug back in. 151 */ 152 struct in_ifadown_arg { 153 struct ifaddr *ifa; 154 int del; 155 }; 156 157 static int 158 in_ifadownkill(const struct rtentry *rt, const struct nhop_object *nh, 159 void *xap) 160 { 161 struct in_ifadown_arg *ap = xap; 162 163 if (nh->nh_ifa != ap->ifa) 164 return (0); 165 166 if ((nhop_get_rtflags(nh) & RTF_STATIC) != 0 && ap->del == 0) 167 return (0); 168 169 return (1); 170 } 171 172 void 173 in_ifadown(struct ifaddr *ifa, int delete) 174 { 175 struct in_ifadown_arg arg; 176 177 KASSERT(ifa->ifa_addr->sa_family == AF_INET, 178 ("%s: wrong family", __func__)); 179 180 arg.ifa = ifa; 181 arg.del = delete; 182 183 rib_foreach_table_walk_del(AF_INET, in_ifadownkill, &arg); 184 ifa->ifa_flags &= ~IFA_ROUTE; /* XXXlocking? */ 185 } 186