/* $NetBSD: in_l2tp.c,v 1.16.4.1 2019/09/24 03:10:35 martin Exp $ */ /* * Copyright (c) 2017 Internet Initiative Japan Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include __KERNEL_RCSID(0, "$NetBSD: in_l2tp.c,v 1.16.4.1 2019/09/24 03:10:35 martin Exp $"); #ifdef _KERNEL_OPT #include "opt_l2tp.h" #endif #include #include #include #include #include #include #include #include #include #include /* For softnet_lock */ #include #include #include #include #include #include #include #include #include #include #include #ifdef ALTQ #include #endif /* TODO: IP_TCPMSS support */ #undef IP_TCPMSS #ifdef IP_TCPMSS #include #endif #include int ip_l2tp_ttl = L2TP_TTL; static void in_l2tp_input(struct mbuf *, int, int, void *); static const struct encapsw in_l2tp_encapsw = { .encapsw4 = { .pr_input = in_l2tp_input, .pr_ctlinput = NULL, } }; static int in_l2tp_match(struct mbuf *, int, int, void *); int in_l2tp_output(struct l2tp_variant *var, struct mbuf *m) { struct l2tp_softc *sc; struct ifnet *ifp; struct sockaddr_in *sin_src = satosin(var->lv_psrc); struct sockaddr_in *sin_dst = satosin(var->lv_pdst); struct ip iphdr; /* capsule IP header, host byte ordered */ struct rtentry *rt; struct route *ro_pc; kmutex_t *lock_pc; int error; uint32_t sess_id; KASSERT(var != NULL); KASSERT(l2tp_heldref_variant(var)); KASSERT(sin_src != NULL && sin_dst != NULL); KASSERT(sin_src->sin_family == AF_INET && sin_dst->sin_family == AF_INET); sc = var->lv_softc; ifp = &sc->l2tp_ec.ec_if; error = l2tp_check_nesting(ifp, m); if (error) { m_freem(m); goto looped; } /* bidirectional configured tunnel mode */ if (sin_dst->sin_addr.s_addr == INADDR_ANY) { m_freem(m); if ((ifp->if_flags & IFF_DEBUG) != 0) log(LOG_DEBUG, "%s: ENETUNREACH\n", __func__); error = ENETUNREACH; goto out; } #ifdef NOTYET /* TODO: support ALTQ for innner frame */ #ifdef ALTQ ALTQ_SAVE_PAYLOAD(m, AF_ETHER); #endif #endif memset(&iphdr, 0, sizeof(iphdr)); iphdr.ip_src = sin_src->sin_addr; iphdr.ip_dst = sin_dst->sin_addr; iphdr.ip_p = IPPROTO_L2TP; /* version will be set in ip_output() */ iphdr.ip_ttl = ip_l2tp_ttl; /* outer IP header length */ iphdr.ip_len = sizeof(struct ip); /* session-id length */ iphdr.ip_len += sizeof(uint32_t); if (var->lv_use_cookie == L2TP_COOKIE_ON) { /* cookie length */ iphdr.ip_len += var->lv_peer_cookie_len; } /* TODO: IP_TCPMSS support */ #ifdef IP_TCPMSS m = l2tp_tcpmss_clamp(ifp, m); if (m == NULL) { error = EINVAL; goto out; } #endif /* * Payload length. * * NOTE: payload length may be changed in ip_tcpmss(). Typical case * is missing of TCP mss option in original TCP header. */ iphdr.ip_len += m->m_pkthdr.len; HTONS(iphdr.ip_len); if (var->lv_use_cookie == L2TP_COOKIE_ON) { /* prepend session cookie */ uint32_t cookie_32; uint64_t cookie_64; M_PREPEND(m, var->lv_peer_cookie_len, M_DONTWAIT); if (m && m->m_len < var->lv_peer_cookie_len) m = m_pullup(m, var->lv_peer_cookie_len); if (m == NULL) { error = ENOBUFS; goto out; } if (var->lv_peer_cookie_len == 4) { cookie_32 = htonl((uint32_t)var->lv_peer_cookie); memcpy(mtod(m, void *), &cookie_32, sizeof(uint32_t)); } else { cookie_64 = htobe64(var->lv_peer_cookie); memcpy(mtod(m, void *), &cookie_64, sizeof(uint64_t)); } } /* prepend session-ID */ sess_id = htonl(var->lv_peer_sess_id); M_PREPEND(m, sizeof(uint32_t), M_DONTWAIT); if (m && m->m_len < sizeof(uint32_t)) m = m_pullup(m, sizeof(uint32_t)); if (m == NULL) { error = ENOBUFS; goto out; } memcpy(mtod(m, uint32_t *), &sess_id, sizeof(uint32_t)); /* prepend new IP header */ M_PREPEND(m, sizeof(struct ip), M_DONTWAIT); if (m == NULL) { error = ENOBUFS; goto out; } if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) { m = m_copyup(m, sizeof(struct ip), 0); } else { if (m->m_len < sizeof(struct ip)) m = m_pullup(m, sizeof(struct ip)); } if (m == NULL) { error = ENOBUFS; goto out; } memcpy(mtod(m, struct ip *), &iphdr, sizeof(struct ip)); if_tunnel_get_ro(sc->l2tp_ro_percpu, &ro_pc, &lock_pc); if ((rt = rtcache_lookup(ro_pc, var->lv_pdst)) == NULL) { if_tunnel_put_ro(sc->l2tp_ro_percpu, lock_pc); m_freem(m); error = ENETUNREACH; goto out; } if (rt->rt_ifp == ifp) { rtcache_unref(rt, ro_pc); rtcache_free(ro_pc); if_tunnel_put_ro(sc->l2tp_ro_percpu, lock_pc); m_freem(m); error = ENETUNREACH; /*XXX*/ goto out; } rtcache_unref(rt, ro_pc); /* * To avoid inappropriate rewrite of checksum, * clear csum flags. */ m->m_pkthdr.csum_flags = 0; error = ip_output(m, NULL, ro_pc, 0, NULL, NULL); if_tunnel_put_ro(sc->l2tp_ro_percpu, lock_pc); return error; looped: if (error) ifp->if_oerrors++; out: return error; } static void in_l2tp_input(struct mbuf *m, int off, int proto, void *eparg __unused) { struct ifnet *l2tpp = NULL; struct l2tp_softc *sc; uint32_t sess_id; uint32_t cookie_32; uint64_t cookie_64; struct psref psref; struct l2tp_variant *var; KASSERT((m->m_flags & M_PKTHDR) != 0); if (m->m_pkthdr.len < off + sizeof(uint32_t)) { m_freem(m); return; } /* get L2TP session ID */ m_copydata(m, off, sizeof(uint32_t), (void *)&sess_id); NTOHL(sess_id); #ifdef L2TP_DEBUG log(LOG_DEBUG, "%s: sess_id = %" PRIu32 "\n", __func__, sess_id); #endif if (sess_id == 0) { /* * L2TPv3 control packet received. * userland daemon(l2tpd?) should process. */ SOFTNET_LOCK_IF_NET_MPSAFE(); rip_input(m, off, proto); SOFTNET_UNLOCK_IF_NET_MPSAFE(); return; } var = l2tp_lookup_session_ref(sess_id, &psref); if (var == NULL) { m_freem(m); ip_statinc(IP_STAT_NOL2TP); return; } sc = var->lv_softc; l2tpp = &(sc->l2tp_ec.ec_if); if (l2tpp == NULL || (l2tpp->if_flags & IFF_UP) == 0) { #ifdef L2TP_DEBUG if (l2tpp == NULL) log(LOG_DEBUG, "%s: l2tpp is NULL\n", __func__); else log(LOG_DEBUG, "%s: l2tpp is down\n", __func__); #endif m_freem(m); ip_statinc(IP_STAT_NOL2TP); goto out; } /* other CPU did l2tp_delete_tunnel */ if (var->lv_psrc == NULL || var->lv_pdst == NULL) { m_freem(m); ip_statinc(IP_STAT_NOL2TP); goto out; } if (var->lv_state != L2TP_STATE_UP) { m_freem(m); goto out; } m_adj(m, off + sizeof(uint32_t)); if (var->lv_use_cookie == L2TP_COOKIE_ON) { if (m->m_pkthdr.len < var->lv_my_cookie_len) { m_freem(m); goto out; } if (var->lv_my_cookie_len == 4) { m_copydata(m, 0, sizeof(uint32_t), (void *)&cookie_32); NTOHL(cookie_32); if (cookie_32 != var->lv_my_cookie) { m_freem(m); goto out; } m_adj(m, sizeof(uint32_t)); } else { m_copydata(m, 0, sizeof(uint64_t), (void *)&cookie_64); BE64TOH(cookie_64); if (cookie_64 != var->lv_my_cookie) { m_freem(m); goto out; } m_adj(m, sizeof(uint64_t)); } } /* TODO: IP_TCPMSS support */ #ifdef IP_TCPMSS m = l2tp_tcpmss_clamp(l2tpp, m); if (m == NULL) goto out; #endif l2tp_input(m, l2tpp); out: l2tp_putref_variant(var, &psref); return; } /* * This function is used by encap4_lookup() to decide priority of the encaptab. * This priority is compared to the match length between mbuf's source/destination * IPv4 address pair and encaptab's one. * l2tp(4) does not use address pairs to search matched encaptab, so this * function must return the length bigger than or equals to IPv4 address pair to * avoid wrong encaptab. */ static int in_l2tp_match(struct mbuf *m, int off, int proto, void *arg) { struct l2tp_softc *sc = arg; struct l2tp_variant *var; struct psref psref; uint32_t sess_id; int rv = 0; KASSERT(proto == IPPROTO_L2TP); var = l2tp_getref_variant(sc, &psref); if (__predict_false(var == NULL)) return rv; /* * If the packet contains no session ID it cannot match */ if (m_length(m) < off + sizeof(uint32_t)) { rv = 0; goto out; } /* get L2TP session ID */ m_copydata(m, off, sizeof(uint32_t), (void *)&sess_id); NTOHL(sess_id); if (sess_id == 0) { /* * L2TPv3 control packet received. * userland daemon(l2tpd?) should process. */ rv = 32 * 2; } else if (sess_id == var->lv_my_sess_id) rv = 32 * 2; else rv = 0; out: l2tp_putref_variant(var, &psref); return rv; } int in_l2tp_attach(struct l2tp_variant *var) { struct l2tp_softc *sc = var->lv_softc; if (sc == NULL) return EINVAL; var->lv_encap_cookie = encap_attach_func(AF_INET, IPPROTO_L2TP, in_l2tp_match, &in_l2tp_encapsw, sc); if (var->lv_encap_cookie == NULL) return EEXIST; return 0; } int in_l2tp_detach(struct l2tp_variant *var) { int error; error = encap_detach(var->lv_encap_cookie); if (error == 0) var->lv_encap_cookie = NULL; return error; }