1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1990, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * Copyright (c) 2019 Andrey V. Elsukov <ae@FreeBSD.org> 7 * Copyright (c) 2025 Gleb Smirnoff <glebius@FreeBSD.org> 8 * 9 * This code is derived from the Stanford/CMU enet packet filter, 10 * (net/enet.c) distributed as part of 4.3BSD, and code contributed 11 * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence 12 * Berkeley Laboratory. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/mbuf.h> 40 #include <sys/socket.h> 41 #include <net/bpf.h> 42 #include <net/bpfdesc.h> 43 #include <net/if.h> 44 #include <net/if_var.h> 45 #include <net/if_private.h> 46 #include <net/if_types.h> 47 #include <net/route.h> 48 49 /* We need to know all the ifnets we support. */ 50 #include <net/if_dl.h> 51 #include <net/ethernet.h> 52 #include <net/firewire.h> 53 #include <net/if_pflog.h> 54 #include <net/if_pfsync.h> 55 56 #include <security/mac/mac_framework.h> 57 58 static int 59 bpf_ifnet_write(void *arg, struct mbuf *m, struct mbuf *mc, int flags) 60 { 61 struct ifnet *ifp = arg; 62 struct route ro = {}; 63 struct sockaddr dst = { 64 .sa_family = AF_UNSPEC, 65 }; 66 u_int hlen; 67 int error; 68 69 NET_EPOCH_ASSERT(); 70 71 if (__predict_false((ifp->if_flags & IFF_UP) == 0)) { 72 m_freem(m); 73 m_freem(mc); 74 return (ENETDOWN); 75 } 76 77 switch (ifp->if_type) { 78 /* DLT_RAW */ 79 case IFT_MBIM: /* umb(4) */ 80 case IFT_OTHER: /* uhso(4), usie */ 81 hlen = 0; 82 break; 83 84 /* DLT_ENC */ 85 case IFT_ENC: 86 hlen = 12; /* XXXGL: sizeof(struct enchdr); */ 87 break; 88 89 /* DLT_EN10MB */ 90 case IFT_ETHER: /* if_ethersubr.c */ 91 case IFT_L2VLAN: /* vlan(4) */ 92 case IFT_BRIDGE: /* if_bridge(4) */ 93 case IFT_IEEE8023ADLAG: /* lagg(4) */ 94 case IFT_INFINIBAND: /* if_infiniband.c */ 95 { 96 struct ether_header *eh; 97 98 eh = mtod(m, struct ether_header *); 99 if (ETHER_IS_MULTICAST(eh->ether_dhost)) { 100 if (bcmp(ifp->if_broadcastaddr, eh->ether_dhost, 101 ETHER_ADDR_LEN) == 0) 102 m->m_flags |= M_BCAST; 103 else 104 m->m_flags |= M_MCAST; 105 } 106 if (!(flags & BPFD_HDRCMPLT)) { 107 memcpy(eh->ether_shost, IF_LLADDR(ifp), 108 sizeof(eh->ether_shost)); 109 } 110 hlen = ETHER_HDR_LEN; 111 break; 112 } 113 /* DLT_APPLE_IP_OVER_IEEE1394 */ 114 case IFT_IEEE1394: /* fwip(4) */ 115 hlen = sizeof(struct fw_hwaddr); 116 break; 117 118 /* DLT_NULL */ 119 case IFT_GIF: /* gif(4) */ 120 case IFT_LOOP: /* lo(4), disc(4) */ 121 case IFT_PARA: /* plip(4), iic */ 122 case IFT_PPP: /* tun(4) */ 123 case IFT_PROPVIRTUAL: /* ng_iface(4) */ 124 case IFT_WIREGUARD: /* wg(4) */ 125 case IFT_STF: /* stf(4) */ 126 case IFT_TUNNEL: /* ipsec(4), me(4), gre(4), ovpn(4) */ 127 hlen = sizeof(uint32_t); 128 break; 129 130 /* DLT_PFSYNC */ 131 case IFT_PFSYNC: 132 hlen = PFSYNC_HDRLEN; 133 break; 134 135 default: 136 hlen = 0; /* pacify compiler */ 137 KASSERT(0, ("%s: ifp %p type %u not supported", __func__, 138 ifp, ifp->if_type)); 139 } 140 141 if (__predict_false(hlen > m->m_len)) { 142 m_freem(m); 143 m_freem(mc); 144 return (EMSGSIZE); 145 }; 146 147 if (hlen != 0) { 148 MPASS(hlen <= sizeof(dst.sa_data)); 149 bcopy(mtod(m, const void *), &dst.sa_data, hlen); 150 ro.ro_prepend = (char *)&dst.sa_data; 151 ro.ro_plen = hlen; 152 ro.ro_flags = RT_HAS_HEADER; 153 m->m_pkthdr.len -= hlen; 154 m->m_len -= hlen; 155 m->m_data += hlen; 156 }; 157 158 CURVNET_SET(ifp->if_vnet); 159 error = ifp->if_output(ifp, m, &dst, &ro); 160 if (error != 0) { 161 m_freem(mc); 162 } else if (mc != NULL) { 163 mc->m_pkthdr.rcvif = ifp; 164 (void)ifp->if_input(ifp, mc); 165 } 166 CURVNET_RESTORE(); 167 168 return (error); 169 } 170 171 static bool 172 bpf_ifnet_chkdir(void *arg, const struct mbuf *m, int dir) 173 { 174 struct ifnet *ifp = arg; 175 struct ifnet *rcvif = m_rcvif(m); 176 177 return ((dir == BPF_D_IN && ifp != rcvif) || 178 (dir == BPF_D_OUT && ifp == rcvif)); 179 } 180 181 uint32_t 182 bpf_ifnet_wrsize(void *arg) 183 { 184 struct ifnet *ifp = arg; 185 186 return (ifp->if_mtu); 187 } 188 189 int 190 bpf_ifnet_promisc(void *arg, bool on) 191 { 192 struct ifnet *ifp = arg; 193 int error; 194 195 CURVNET_SET(ifp->if_vnet); 196 if ((error = ifpromisc(ifp, on ? 1 : 0)) != 0) 197 if_printf(ifp, "%s: ifpromisc failed (%d)\n", __func__, error); 198 CURVNET_RESTORE(); 199 200 return (error); 201 } 202 203 #ifdef MAC 204 static int 205 bpf_ifnet_mac_check_receive(void *arg, struct bpf_d *d) 206 { 207 struct ifnet *ifp = arg; 208 209 return (mac_bpfdesc_check_receive(d, ifp)); 210 } 211 #endif 212 213 static const struct bif_methods bpf_ifnet_methods = { 214 .bif_chkdir = bpf_ifnet_chkdir, 215 .bif_promisc = bpf_ifnet_promisc, 216 .bif_wrsize = bpf_ifnet_wrsize, 217 .bif_write = bpf_ifnet_write, 218 #ifdef MAC 219 .bif_mac_check_receive = bpf_ifnet_mac_check_receive, 220 #endif 221 }; 222 223 /* 224 * Attach an interface to bpf. dlt is the link layer type; hdrlen is the 225 * fixed size of the link header (variable length headers not yet supported). 226 * Legacy KPI to be obsoleted soon. 227 */ 228 void 229 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen) 230 { 231 232 ifp->if_bpf = bpf_attach(ifp->if_xname, dlt, hdrlen, 233 &bpf_ifnet_methods, ifp); 234 if_ref(ifp); 235 if (bootverbose && IS_DEFAULT_VNET(curvnet)) 236 if_printf(ifp, "bpf attached\n"); 237 } 238 239 /* 240 * The dead_bpf_if is an ugly plug against races at ifnet destroy time that 241 * still exist and are not properly covered by epoch(9). 242 * Legacy KPI to be obsoleted soon. 243 */ 244 void 245 bpfdetach(struct ifnet *ifp) 246 { 247 static const struct bpfd_list dead_bpf_if = CK_LIST_HEAD_INITIALIZER(); 248 struct bpf_if *bif; 249 250 bif = ifp->if_bpf; 251 ifp->if_bpf = __DECONST(struct bpf_if *, &dead_bpf_if); 252 bpf_detach(bif); 253 if_rele(ifp); 254 } 255