429 lines
10 KiB
C
429 lines
10 KiB
C
/* $NetBSD: in6_l2tp.c,v 1.17 2018/09/03 02:33:31 knakahara Exp $ */
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/*
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* Copyright (c) 2017 Internet Initiative Japan Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: in6_l2tp.c,v 1.17 2018/09/03 02:33:31 knakahara Exp $");
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#ifdef _KERNEL_OPT
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#include "opt_l2tp.h"
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#endif
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/socket.h>
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#include <sys/sockio.h>
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#include <sys/mbuf.h>
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#include <sys/errno.h>
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#include <sys/ioctl.h>
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#include <sys/syslog.h>
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#include <sys/kernel.h>
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#include <net/if.h>
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#include <net/route.h>
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#include <net/if_ether.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/ip_var.h>
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#include <netinet/ip_private.h>
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#include <netinet/in_l2tp.h>
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#include <netinet/in_var.h>
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#include <netinet/ip_encap.h>
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#include <netinet/ip6.h>
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#include <netinet6/ip6_var.h>
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#include <netinet6/in6_l2tp.h>
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#ifdef ALTQ
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#include <altq/altq.h>
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#endif
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/* TODO: IP_TCPMSS support */
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#undef IP_TCPMSS
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#ifdef IP_TCPMSS
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#include <netinet/ip_tcpmss.h>
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#endif
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#include <net/if_l2tp.h>
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#define L2TP_HLIM6 64
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int ip6_l2tp_hlim = L2TP_HLIM6;
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static int in6_l2tp_input(struct mbuf **, int *, int, void *);
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static const struct encapsw in6_l2tp_encapsw = {
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.encapsw6 = {
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.pr_input = in6_l2tp_input,
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.pr_ctlinput = NULL,
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}
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};
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static int in6_l2tp_match(struct mbuf *, int, int, void *);
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int
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in6_l2tp_output(struct l2tp_variant *var, struct mbuf *m)
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{
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struct rtentry *rt;
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struct l2tp_ro *lro;
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struct l2tp_softc *sc;
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struct ifnet *ifp;
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struct sockaddr_in6 *sin6_src = satosin6(var->lv_psrc);
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struct sockaddr_in6 *sin6_dst = satosin6(var->lv_pdst);
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struct ip6_hdr ip6hdr; /* capsule IP header, host byte ordered */
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int error;
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uint32_t sess_id;
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KASSERT(var != NULL);
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KASSERT(l2tp_heldref_variant(var));
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KASSERT(sin6_src != NULL && sin6_dst != NULL);
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KASSERT(sin6_src->sin6_family == AF_INET6
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&& sin6_dst->sin6_family == AF_INET6);
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sc = var->lv_softc;
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ifp = &sc->l2tp_ec.ec_if;
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error = l2tp_check_nesting(ifp, m);
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if (error) {
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m_freem(m);
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goto looped;
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}
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/* bidirectional configured tunnel mode */
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if (IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr)) {
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m_freem(m);
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if ((ifp->if_flags & IFF_DEBUG) != 0)
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log(LOG_DEBUG, "%s: ENETUNREACH\n", __func__);
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return ENETUNREACH;
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}
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#ifdef NOTYET
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/* TODO: support ALTQ for innner frame */
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#ifdef ALTQ
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ALTQ_SAVE_PAYLOAD(m, AF_ETHER);
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#endif
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#endif
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memset(&ip6hdr, 0, sizeof(ip6hdr));
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ip6hdr.ip6_src = sin6_src->sin6_addr;
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ip6hdr.ip6_dst = sin6_dst->sin6_addr;
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/* unlike IPv4, IP version must be filled by caller of ip6_output() */
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ip6hdr.ip6_vfc = 0x60;
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ip6hdr.ip6_nxt = IPPROTO_L2TP;
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ip6hdr.ip6_hlim = ip6_l2tp_hlim;
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/* outer IP payload length */
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ip6hdr.ip6_plen = 0;
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/* session-id length */
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ip6hdr.ip6_plen += sizeof(uint32_t);
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if (var->lv_use_cookie == L2TP_COOKIE_ON) {
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/* cookie length */
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ip6hdr.ip6_plen += var->lv_peer_cookie_len;
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}
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/* TODO: IP_TCPMSS support */
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#ifdef IP_TCPMSS
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m = l2tp_tcpmss_clamp(ifp, m);
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if (m == NULL)
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return EINVAL;
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#endif
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/*
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* Payload length.
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*
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* NOTE: payload length may be changed in ip_tcpmss(). Typical case
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* is missing of TCP mss option in original TCP header.
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*/
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ip6hdr.ip6_plen += m->m_pkthdr.len;
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HTONS(ip6hdr.ip6_plen);
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if (var->lv_use_cookie == L2TP_COOKIE_ON) {
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/* prepend session cookie */
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uint32_t cookie_32;
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uint64_t cookie_64;
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M_PREPEND(m, var->lv_peer_cookie_len, M_DONTWAIT);
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if (m && m->m_len < var->lv_peer_cookie_len)
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m = m_pullup(m, var->lv_peer_cookie_len);
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if (m == NULL)
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return ENOBUFS;
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if (var->lv_peer_cookie_len == 4) {
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cookie_32 = htonl((uint32_t)var->lv_peer_cookie);
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memcpy(mtod(m, void *), &cookie_32, sizeof(uint32_t));
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} else {
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cookie_64 = htobe64(var->lv_peer_cookie);
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memcpy(mtod(m, void *), &cookie_64, sizeof(uint64_t));
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}
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}
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/* prepend session-ID */
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sess_id = htonl(var->lv_peer_sess_id);
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M_PREPEND(m, sizeof(uint32_t), M_DONTWAIT);
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if (m && m->m_len < sizeof(uint32_t))
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m = m_pullup(m, sizeof(uint32_t));
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if (m == NULL)
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return ENOBUFS;
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memcpy(mtod(m, uint32_t *), &sess_id, sizeof(uint32_t));
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/* prepend new IP header */
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M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
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if (m == NULL)
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return ENOBUFS;
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if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) {
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m = m_copyup(m, sizeof(struct ip), 0);
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} else {
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if (m->m_len < sizeof(struct ip6_hdr))
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m = m_pullup(m, sizeof(struct ip6_hdr));
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}
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if (m == NULL)
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return ENOBUFS;
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memcpy(mtod(m, struct ip6_hdr *), &ip6hdr, sizeof(struct ip6_hdr));
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lro = percpu_getref(sc->l2tp_ro_percpu);
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mutex_enter(lro->lr_lock);
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if ((rt = rtcache_lookup(&lro->lr_ro, var->lv_pdst)) == NULL) {
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mutex_exit(lro->lr_lock);
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percpu_putref(sc->l2tp_ro_percpu);
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m_freem(m);
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return ENETUNREACH;
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}
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/* If the route constitutes infinite encapsulation, punt. */
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if (rt->rt_ifp == ifp) {
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rtcache_unref(rt, &lro->lr_ro);
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rtcache_free(&lro->lr_ro);
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mutex_exit(lro->lr_lock);
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percpu_putref(sc->l2tp_ro_percpu);
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m_freem(m);
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return ENETUNREACH; /* XXX */
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}
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rtcache_unref(rt, &lro->lr_ro);
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/*
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* To avoid inappropriate rewrite of checksum,
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* clear csum flags.
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*/
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m->m_pkthdr.csum_flags = 0;
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error = ip6_output(m, 0, &lro->lr_ro, 0, NULL, NULL, NULL);
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mutex_exit(lro->lr_lock);
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percpu_putref(sc->l2tp_ro_percpu);
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return(error);
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looped:
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if (error)
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ifp->if_oerrors++;
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return error;
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}
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static int
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in6_l2tp_input(struct mbuf **mp, int *offp, int proto, void *eparg __unused)
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{
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struct mbuf *m = *mp;
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int off = *offp;
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struct ifnet *l2tpp = NULL;
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struct l2tp_softc *sc;
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struct l2tp_variant *var;
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uint32_t sess_id;
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uint32_t cookie_32;
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uint64_t cookie_64;
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struct psref psref;
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KASSERT((m->m_flags & M_PKTHDR) != 0);
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if (m->m_pkthdr.len < off + sizeof(uint32_t)) {
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m_freem(m);
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return IPPROTO_DONE;
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}
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/* get L2TP session ID */
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m_copydata(m, off, sizeof(uint32_t), (void *)&sess_id);
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NTOHL(sess_id);
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#ifdef L2TP_DEBUG
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log(LOG_DEBUG, "%s: sess_id = %" PRIu32 "\n", __func__, sess_id);
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#endif
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if (sess_id == 0) {
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int rv;
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/*
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* L2TPv3 control packet received.
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* userland daemon(l2tpd?) should process.
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*/
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SOFTNET_LOCK_IF_NET_MPSAFE();
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rv = rip6_input(mp, offp, proto);
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SOFTNET_UNLOCK_IF_NET_MPSAFE();
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return rv;
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}
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var = l2tp_lookup_session_ref(sess_id, &psref);
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if (var == NULL) {
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m_freem(m);
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IP_STATINC(IP_STAT_NOL2TP);
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return IPPROTO_DONE;
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}
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sc = var->lv_softc;
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l2tpp = &(sc->l2tp_ec.ec_if);
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if (l2tpp == NULL || (l2tpp->if_flags & IFF_UP) == 0) {
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#ifdef L2TP_DEBUG
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if (l2tpp == NULL)
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log(LOG_DEBUG, "%s: l2tpp is NULL\n", __func__);
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else
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log(LOG_DEBUG, "%s: l2tpp is down\n", __func__);
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#endif
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m_freem(m);
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IP_STATINC(IP_STAT_NOL2TP);
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goto out;
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}
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/* other CPU did l2tp_delete_tunnel */
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if (var->lv_psrc == NULL || var->lv_pdst == NULL) {
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m_freem(m);
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ip_statinc(IP_STAT_NOL2TP);
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goto out;
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}
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if (var->lv_state != L2TP_STATE_UP) {
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m_freem(m);
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goto out;
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}
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m_adj(m, off + sizeof(uint32_t));
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if (var->lv_use_cookie == L2TP_COOKIE_ON) {
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if (m->m_pkthdr.len < var->lv_my_cookie_len) {
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m_freem(m);
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goto out;
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}
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if (var->lv_my_cookie_len == 4) {
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m_copydata(m, 0, sizeof(uint32_t), (void *)&cookie_32);
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NTOHL(cookie_32);
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if (cookie_32 != var->lv_my_cookie) {
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m_freem(m);
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goto out;
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}
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m_adj(m, sizeof(uint32_t));
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} else {
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m_copydata(m, 0, sizeof(uint64_t), (void *)&cookie_64);
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BE64TOH(cookie_64);
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if (cookie_64 != var->lv_my_cookie) {
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m_freem(m);
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goto out;
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}
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m_adj(m, sizeof(uint64_t));
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}
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}
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/* TODO: IP_TCPMSS support */
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#ifdef IP_TCPMSS
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m = l2tp_tcpmss_clamp(l2tpp, m);
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if (m == NULL)
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goto out;
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#endif
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l2tp_input(m, l2tpp);
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out:
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l2tp_putref_variant(var, &psref);
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return IPPROTO_DONE;
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}
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/*
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* This function is used by encap6_lookup() to decide priority of the encaptab.
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* This priority is compared to the match length between mbuf's source/destination
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* IPv6 address pair and encaptab's one.
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* l2tp(4) does not use address pairs to search matched encaptab, so this
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* function must return the length bigger than or equals to IPv6 address pair to
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* avoid wrong encaptab.
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*/
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static int
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in6_l2tp_match(struct mbuf *m, int off, int proto, void *arg)
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{
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struct l2tp_softc *sc = arg;
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struct l2tp_variant *var;
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struct psref psref;
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uint32_t sess_id;
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int rv = 0;
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KASSERT(proto == IPPROTO_L2TP);
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var = l2tp_getref_variant(sc, &psref);
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if (__predict_false(var == NULL))
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return rv;
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/*
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* If the packet contains no session ID it cannot match
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*/
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if (m_length(m) < off + sizeof(uint32_t)) {
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rv = 0 ;
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goto out;
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}
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/* get L2TP session ID */
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m_copydata(m, off, sizeof(uint32_t), (void *)&sess_id);
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NTOHL(sess_id);
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if (sess_id == 0) {
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/*
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* L2TPv3 control packet received.
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* userland daemon(l2tpd?) should process.
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*/
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rv = 128 * 2;
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} else if (sess_id == var->lv_my_sess_id)
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rv = 128 * 2;
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else
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rv = 0;
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out:
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l2tp_putref_variant(var, &psref);
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return rv;
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}
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int
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in6_l2tp_attach(struct l2tp_variant *var)
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{
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struct l2tp_softc *sc = var->lv_softc;
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if (sc == NULL)
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return EINVAL;
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var->lv_encap_cookie = encap_attach_func(AF_INET6, IPPROTO_L2TP,
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in6_l2tp_match, &in6_l2tp_encapsw, sc);
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if (var->lv_encap_cookie == NULL)
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return EEXIST;
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return 0;
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}
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int
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in6_l2tp_detach(struct l2tp_variant *var)
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{
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int error;
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error = encap_detach(var->lv_encap_cookie);
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if (error == 0)
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var->lv_encap_cookie = NULL;
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return error;
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}
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