/*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1982, 1986, 1988, 1993 * The Regents of the University of California. 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. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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 __FBSDID("$FreeBSD$"); #include "opt_inet.h" #include "opt_inet6.h" #include "opt_sctp.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef INET6 #include #include #endif #if defined(SCTP) || defined(SCTP_SUPPORT) #include #endif #include /* * Divert sockets */ /* * Allocate enough space to hold a full IP packet */ #define DIVSNDQ (65536 + 100) #define DIVRCVQ (65536 + 100) /* * Usually a system has very few divert ports. Previous implementation * used a linked list. */ #define DIVHASHSIZE (1 << 3) /* 8 entries, one cache line. */ #define DIVHASH(port) (port % DIVHASHSIZE) #define DCBHASH(dcb) ((dcb)->dcb_port % DIVHASHSIZE) /* * Divert sockets work in conjunction with ipfw or other packet filters, * see the divert(4) manpage for features. * Packets are selected by the packet filter and tagged with an * MTAG_IPFW_RULE tag carrying the 'divert port' number (as set by * the packet filter) and information on the matching filter rule for * subsequent reinjection. The divert_port is used to put the packet * on the corresponding divert socket, while the rule number is passed * up (at least partially) as the sin_port in the struct sockaddr. * * Packets written to the divert socket carry in sin_addr a * destination address, and in sin_port the number of the filter rule * after which to continue processing. * If the destination address is INADDR_ANY, the packet is treated as * as outgoing and sent to ip_output(); otherwise it is treated as * incoming and sent to ip_input(). * Further, sin_zero carries some information on the interface, * which can be used in the reinject -- see comments in the code. * * On reinjection, processing in ip_input() and ip_output() * will be exactly the same as for the original packet, except that * packet filter processing will start at the rule number after the one * written in the sin_port (ipfw does not allow a rule #0, so sin_port=0 * will apply the entire ruleset to the packet). */ static SYSCTL_NODE(_net_inet, OID_AUTO, divert, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, "divert(4)"); VNET_PCPUSTAT_DEFINE_STATIC(struct divstat, divstat); VNET_PCPUSTAT_SYSINIT(divstat); #ifdef VIMAGE VNET_PCPUSTAT_SYSUNINIT(divstat); #endif SYSCTL_VNET_PCPUSTAT(_net_inet_divert, OID_AUTO, stats, struct divstat, divstat, "divert(4) socket statistics"); #define DIVSTAT_INC(name) \ VNET_PCPUSTAT_ADD(struct divstat, divstat, div_ ## name, 1) static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ static int div_output_inbound(int fmaily, struct socket *so, struct mbuf *m, struct sockaddr_in *sin); static int div_output_outbound(int family, struct socket *so, struct mbuf *m); struct divcb { union { SLIST_ENTRY(divcb) dcb_next; intptr_t dcb_bound; #define DCB_UNBOUND ((intptr_t)-1) }; struct socket *dcb_socket; uint16_t dcb_port; uint64_t dcb_gencnt; struct epoch_context dcb_epochctx; }; SLIST_HEAD(divhashhead, divcb); VNET_DEFINE_STATIC(struct divhashhead, divhash[DIVHASHSIZE]) = {}; #define V_divhash VNET(divhash) VNET_DEFINE_STATIC(uint64_t, dcb_count) = 0; #define V_dcb_count VNET(dcb_count) VNET_DEFINE_STATIC(uint64_t, dcb_gencnt) = 0; #define V_dcb_gencnt VNET(dcb_gencnt) static struct mtx divert_mtx; MTX_SYSINIT(divert, &divert_mtx, "divert(4) socket pcb lists", MTX_DEF); #define DIVERT_LOCK() mtx_lock(&divert_mtx) #define DIVERT_UNLOCK() mtx_unlock(&divert_mtx) /* * Divert a packet by passing it up to the divert socket at port 'port'. */ static void divert_packet(struct mbuf *m, bool incoming) { struct divcb *dcb; u_int16_t nport; struct sockaddr_in divsrc; struct m_tag *mtag; NET_EPOCH_ASSERT(); mtag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL); if (mtag == NULL) { m_freem(m); return; } /* Assure header */ if (m->m_len < sizeof(struct ip) && (m = m_pullup(m, sizeof(struct ip))) == NULL) return; #ifdef INET /* Delayed checksums are currently not compatible with divert. */ if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { in_delayed_cksum(m); m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; } #if defined(SCTP) || defined(SCTP_SUPPORT) if (m->m_pkthdr.csum_flags & CSUM_SCTP) { struct ip *ip; ip = mtod(m, struct ip *); sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2)); m->m_pkthdr.csum_flags &= ~CSUM_SCTP; } #endif #endif #ifdef INET6 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) { in6_delayed_cksum(m, m->m_pkthdr.len - sizeof(struct ip6_hdr), sizeof(struct ip6_hdr)); m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6; } #if defined(SCTP) || defined(SCTP_SUPPORT) if (m->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) { sctp_delayed_cksum(m, sizeof(struct ip6_hdr)); m->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6; } #endif #endif /* INET6 */ bzero(&divsrc, sizeof(divsrc)); divsrc.sin_len = sizeof(divsrc); divsrc.sin_family = AF_INET; /* record matching rule, in host format */ divsrc.sin_port = ((struct ipfw_rule_ref *)(mtag+1))->rulenum; /* * Record receive interface address, if any. * But only for incoming packets. */ if (incoming) { struct ifaddr *ifa; struct ifnet *ifp; /* Sanity check */ M_ASSERTPKTHDR(m); /* Find IP address for receive interface */ ifp = m->m_pkthdr.rcvif; CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { if (ifa->ifa_addr->sa_family != AF_INET) continue; divsrc.sin_addr = ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr; break; } } /* * Record the incoming interface name whenever we have one. */ if (m->m_pkthdr.rcvif) { /* * Hide the actual interface name in there in the * sin_zero array. XXX This needs to be moved to a * different sockaddr type for divert, e.g. * sockaddr_div with multiple fields like * sockaddr_dl. Presently we have only 7 bytes * but that will do for now as most interfaces * are 4 or less + 2 or less bytes for unit. * There is probably a faster way of doing this, * possibly taking it from the sockaddr_dl on the iface. * This solves the problem of a P2P link and a LAN interface * having the same address, which can result in the wrong * interface being assigned to the packet when fed back * into the divert socket. Theoretically if the daemon saves * and re-uses the sockaddr_in as suggested in the man pages, * this iface name will come along for the ride. * (see div_output for the other half of this.) */ strlcpy(divsrc.sin_zero, m->m_pkthdr.rcvif->if_xname, sizeof(divsrc.sin_zero)); } /* Put packet on socket queue, if any */ nport = htons((uint16_t)(((struct ipfw_rule_ref *)(mtag+1))->info)); SLIST_FOREACH(dcb, &V_divhash[DIVHASH(nport)], dcb_next) if (dcb->dcb_port == nport) break; if (dcb != NULL) { struct socket *sa = dcb->dcb_socket; SOCKBUF_LOCK(&sa->so_rcv); if (sbappendaddr_locked(&sa->so_rcv, (struct sockaddr *)&divsrc, m, NULL) == 0) { soroverflow_locked(sa); m_freem(m); } else { sorwakeup_locked(sa); DIVSTAT_INC(diverted); } } else { DIVSTAT_INC(noport); m_freem(m); } } /* * Deliver packet back into the IP processing machinery. * * If no address specified, or address is 0.0.0.0, send to ip_output(); * otherwise, send to ip_input() and mark as having been received on * the interface with that address. */ static int div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, struct mbuf *control, struct thread *td) { struct epoch_tracker et; struct sockaddr_in *sin = (struct sockaddr_in *)nam; const struct ip *ip; struct m_tag *mtag; struct ipfw_rule_ref *dt; int error, family; if (control) m_freem(control); /* Packet must have a header (but that's about it) */ if (m->m_len < sizeof (struct ip) && (m = m_pullup(m, sizeof (struct ip))) == NULL) { m_freem(m); return (EINVAL); } if (sin != NULL) { if (sin->sin_family != AF_INET) { m_freem(m); return (EAFNOSUPPORT); } if (sin->sin_len != sizeof(*sin)) { m_freem(m); return (EINVAL); } } /* * An mbuf may hasn't come from userland, but we pretend * that it has. */ m->m_pkthdr.rcvif = NULL; m->m_nextpkt = NULL; M_SETFIB(m, so->so_fibnum); mtag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL); if (mtag == NULL) { /* this should be normal */ mtag = m_tag_alloc(MTAG_IPFW_RULE, 0, sizeof(struct ipfw_rule_ref), M_NOWAIT | M_ZERO); if (mtag == NULL) { m_freem(m); return (ENOBUFS); } m_tag_prepend(m, mtag); } dt = (struct ipfw_rule_ref *)(mtag+1); /* Loopback avoidance and state recovery */ if (sin) { int i; /* set the starting point. We provide a non-zero slot, * but a non_matching chain_id to skip that info and use * the rulenum/rule_id. */ dt->slot = 1; /* dummy, chain_id is invalid */ dt->chain_id = 0; dt->rulenum = sin->sin_port+1; /* host format ? */ dt->rule_id = 0; /* XXX: broken for IPv6 */ /* * Find receive interface with the given name, stuffed * (if it exists) in the sin_zero[] field. * The name is user supplied data so don't trust its size * or that it is zero terminated. */ for (i = 0; i < sizeof(sin->sin_zero) && sin->sin_zero[i]; i++) ; if ( i > 0 && i < sizeof(sin->sin_zero)) m->m_pkthdr.rcvif = ifunit(sin->sin_zero); } ip = mtod(m, struct ip *); switch (ip->ip_v) { #ifdef INET case IPVERSION: family = AF_INET; break; #endif #ifdef INET6 case IPV6_VERSION >> 4: family = AF_INET6; break; #endif default: m_freem(m); return (EAFNOSUPPORT); } /* Reinject packet into the system as incoming or outgoing */ NET_EPOCH_ENTER(et); if (!sin || sin->sin_addr.s_addr == 0) { dt->info |= IPFW_IS_DIVERT | IPFW_INFO_OUT; error = div_output_outbound(family, so, m); } else { dt->info |= IPFW_IS_DIVERT | IPFW_INFO_IN; error = div_output_inbound(family, so, m, sin); } NET_EPOCH_EXIT(et); return (error); } /* * Sends mbuf @m to the wire via ip[6]_output(). * * Returns 0 on success or an errno value on failure. @m is always consumed. */ static int div_output_outbound(int family, struct socket *so, struct mbuf *m) { int error; switch (family) { #ifdef INET case AF_INET: { struct ip *const ip = mtod(m, struct ip *); /* Don't allow packet length sizes that will crash. */ if (((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) { m_freem(m); return (EINVAL); } break; } #endif #ifdef INET6 case AF_INET6: { struct ip6_hdr *const ip6 = mtod(m, struct ip6_hdr *); /* Don't allow packet length sizes that will crash */ if (((u_short)ntohs(ip6->ip6_plen) > m->m_pkthdr.len)) { m_freem(m); return (EINVAL); } break; } #endif } #ifdef MAC mac_socket_create_mbuf(so, m); #endif error = 0; switch (family) { #ifdef INET case AF_INET: error = ip_output(m, NULL, NULL, ((so->so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0) | IP_ALLOWBROADCAST | IP_RAWOUTPUT, NULL, NULL); break; #endif #ifdef INET6 case AF_INET6: error = ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL); break; #endif } if (error == 0) DIVSTAT_INC(outbound); return (error); } /* * Schedules mbuf @m for local processing via IPv4/IPv6 netisr queue. * * Returns 0 on success or an errno value on failure. @m is always consumed. */ static int div_output_inbound(int family, struct socket *so, struct mbuf *m, struct sockaddr_in *sin) { struct ifaddr *ifa; if (m->m_pkthdr.rcvif == NULL) { /* * No luck with the name, check by IP address. * Clear the port and the ifname to make sure * there are no distractions for ifa_ifwithaddr. */ /* XXX: broken for IPv6 */ bzero(sin->sin_zero, sizeof(sin->sin_zero)); sin->sin_port = 0; ifa = ifa_ifwithaddr((struct sockaddr *) sin); if (ifa == NULL) { m_freem(m); return (EADDRNOTAVAIL); } m->m_pkthdr.rcvif = ifa->ifa_ifp; } #ifdef MAC mac_socket_create_mbuf(so, m); #endif /* Send packet to input processing via netisr */ switch (family) { #ifdef INET case AF_INET: { const struct ip *ip; ip = mtod(m, struct ip *); /* * Restore M_BCAST flag when destination address is * broadcast. It is expected by ip_tryforward(). */ if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) m->m_flags |= M_MCAST; else if (in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif)) m->m_flags |= M_BCAST; netisr_queue_src(NETISR_IP, (uintptr_t)so, m); DIVSTAT_INC(inbound); break; } #endif #ifdef INET6 case AF_INET6: netisr_queue_src(NETISR_IPV6, (uintptr_t)so, m); DIVSTAT_INC(inbound); break; #endif default: m_freem(m); return (EINVAL); } return (0); } static int div_attach(struct socket *so, int proto, struct thread *td) { struct divcb *dcb; int error; if (td != NULL) { error = priv_check(td, PRIV_NETINET_DIVERT); if (error) return (error); } error = soreserve(so, div_sendspace, div_recvspace); if (error) return error; dcb = malloc(sizeof(*dcb), M_PCB, M_WAITOK); dcb->dcb_bound = DCB_UNBOUND; dcb->dcb_socket = so; DIVERT_LOCK(); V_dcb_count++; dcb->dcb_gencnt = ++V_dcb_gencnt; DIVERT_UNLOCK(); so->so_pcb = dcb; return (0); } static void div_free(epoch_context_t ctx) { struct divcb *dcb = __containerof(ctx, struct divcb, dcb_epochctx); free(dcb, M_PCB); } static void div_detach(struct socket *so) { struct divcb *dcb = so->so_pcb; so->so_pcb = NULL; DIVERT_LOCK(); if (dcb->dcb_bound != DCB_UNBOUND) SLIST_REMOVE(&V_divhash[DCBHASH(dcb)], dcb, divcb, dcb_next); V_dcb_count--; V_dcb_gencnt++; DIVERT_UNLOCK(); NET_EPOCH_CALL(div_free, &dcb->dcb_epochctx); } static int div_bind(struct socket *so, struct sockaddr *nam, struct thread *td) { struct divcb *dcb; uint16_t port; if (nam->sa_family != AF_INET) return EAFNOSUPPORT; if (nam->sa_len != sizeof(struct sockaddr_in)) return EINVAL; port = ((struct sockaddr_in *)nam)->sin_port; DIVERT_LOCK(); SLIST_FOREACH(dcb, &V_divhash[DIVHASH(port)], dcb_next) if (dcb->dcb_port == port) { DIVERT_UNLOCK(); return (EADDRINUSE); } dcb = so->so_pcb; if (dcb->dcb_bound != DCB_UNBOUND) SLIST_REMOVE(&V_divhash[DCBHASH(dcb)], dcb, divcb, dcb_next); dcb->dcb_port = port; SLIST_INSERT_HEAD(&V_divhash[DIVHASH(port)], dcb, dcb_next); DIVERT_UNLOCK(); return (0); } static int div_shutdown(struct socket *so) { socantsendmore(so); return 0; } static int div_pcblist(SYSCTL_HANDLER_ARGS) { struct xinpgen xig; struct divcb *dcb; int error; if (req->newptr != 0) return EPERM; if (req->oldptr == 0) { u_int n; n = V_dcb_count; n += imax(n / 8, 10); req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xinpcb); return 0; } if ((error = sysctl_wire_old_buffer(req, 0)) != 0) return (error); bzero(&xig, sizeof(xig)); xig.xig_len = sizeof xig; xig.xig_count = V_dcb_count; xig.xig_gen = V_dcb_gencnt; xig.xig_sogen = so_gencnt; error = SYSCTL_OUT(req, &xig, sizeof xig); if (error) return error; DIVERT_LOCK(); for (int i = 0; i < DIVHASHSIZE; i++) SLIST_FOREACH(dcb, &V_divhash[i], dcb_next) { if (dcb->dcb_gencnt <= xig.xig_gen) { struct xinpcb xi; bzero(&xi, sizeof(xi)); xi.xi_len = sizeof(struct xinpcb); sotoxsocket(dcb->dcb_socket, &xi.xi_socket); xi.inp_gencnt = dcb->dcb_gencnt; xi.inp_vflag = INP_IPV4; /* XXX: netstat(1) */ xi.inp_inc.inc_ie.ie_lport = dcb->dcb_port; error = SYSCTL_OUT(req, &xi, sizeof xi); if (error) goto errout; } } /* * Give the user an updated idea of our state. * If the generation differs from what we told * her before, she knows that something happened * while we were processing this request, and it * might be necessary to retry. */ xig.xig_gen = V_dcb_gencnt; xig.xig_sogen = so_gencnt; xig.xig_count = V_dcb_count; error = SYSCTL_OUT(req, &xig, sizeof xig); errout: DIVERT_UNLOCK(); return (error); } SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, div_pcblist, "S,xinpcb", "List of active divert sockets"); static struct protosw div_protosw = { .pr_type = SOCK_RAW, .pr_flags = PR_ATOMIC|PR_ADDR, .pr_attach = div_attach, .pr_bind = div_bind, .pr_detach = div_detach, .pr_send = div_send, .pr_shutdown = div_shutdown, }; static struct domain divertdomain = { .dom_family = PF_DIVERT, .dom_name = "divert", .dom_nprotosw = 1, .dom_protosw = { &div_protosw }, }; static int div_modevent(module_t mod, int type, void *unused) { int err = 0; switch (type) { case MOD_LOAD: domain_add(&divertdomain); ip_divert_ptr = divert_packet; break; case MOD_QUIESCE: /* * IPDIVERT may normally not be unloaded because of the * potential race conditions. Tell kldunload we can't be * unloaded unless the unload is forced. */ err = EPERM; break; case MOD_UNLOAD: /* * Forced unload. * * Module ipdivert can only be unloaded if no sockets are * connected. Maybe this can be changed later to forcefully * disconnect any open sockets. * * XXXRW: Note that there is a slight race here, as a new * socket open request could be spinning on the lock and then * we destroy the lock. * * XXXGL: One more reason this code is incorrect is that it * checks only the current vnet. */ DIVERT_LOCK(); if (V_dcb_count != 0) { DIVERT_UNLOCK(); err = EBUSY; break; } DIVERT_UNLOCK(); ip_divert_ptr = NULL; domain_remove(&divertdomain); break; default: err = EOPNOTSUPP; break; } return err; } static moduledata_t ipdivertmod = { "ipdivert", div_modevent, 0 }; DECLARE_MODULE(ipdivert, ipdivertmod, SI_SUB_PROTO_FIREWALL, SI_ORDER_ANY); MODULE_VERSION(ipdivert, 1);