/*- * 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. * 4. 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("$FreeBSD$"); #if !defined(KLD_MODULE) #include "opt_inet.h" #include "opt_ipfw.h" #include "opt_mac.h" #ifndef INET #error "IPDIVERT requires INET." #endif #ifndef IPFIREWALL #error "IPDIVERT requires IPFIREWALL" #endif #endif #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 #include #include /* * Divert sockets */ /* * Allocate enough space to hold a full IP packet */ #define DIVSNDQ (65536 + 100) #define DIVRCVQ (65536 + 100) /* * Divert sockets work in conjunction with ipfw, see the divert(4) * manpage for features. * Internally, packets selected by ipfw in ip_input() or ip_output(), * and never diverted before, are passed to the input queue of the * divert socket with a given 'divert_port' number (as specified in * the matching ipfw rule), and they are tagged with a 16 bit cookie * (representing the rule number of the matching ipfw rule), which * is passed to process reading from the socket. * * Packets written to the divert socket are again tagged with a cookie * (usually the same as above) and a destination address. * If the destination address is INADDR_ANY then the packet is * treated as outgoing and sent to ip_output(), otherwise it is * treated as incoming and sent to ip_input(). * In both cases, the packet is tagged with the cookie. * * On reinjection, processing in ip_input() and ip_output() * will be exactly the same as for the original packet, except that * ipfw processing will start at the rule number after the one * written in the cookie (so, tagging a packet with a cookie of 0 * will cause it to be effectively considered as a standard packet). */ /* Internal variables. */ static struct inpcbhead divcb; static struct inpcbinfo divcbinfo; static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ /* * Initialize divert connection block queue. */ static void div_zone_change(void *tag) { uma_zone_set_max(divcbinfo.ipi_zone, maxsockets); } static int div_inpcb_init(void *mem, int size, int flags) { struct inpcb *inp = mem; INP_LOCK_INIT(inp, "inp", "divinp"); return (0); } static void div_inpcb_fini(void *mem, int size) { struct inpcb *inp = mem; INP_LOCK_DESTROY(inp); } void div_init(void) { INP_INFO_LOCK_INIT(&divcbinfo, "div"); LIST_INIT(&divcb); divcbinfo.ipi_listhead = &divcb; /* * XXX We don't use the hash list for divert IP, but it's easier * to allocate a one entry hash list than it is to check all * over the place for hashbase == NULL. */ divcbinfo.ipi_hashbase = hashinit(1, M_PCB, &divcbinfo.ipi_hashmask); divcbinfo.ipi_porthashbase = hashinit(1, M_PCB, &divcbinfo.ipi_porthashmask); divcbinfo.ipi_zone = uma_zcreate("divcb", sizeof(struct inpcb), NULL, NULL, div_inpcb_init, div_inpcb_fini, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); uma_zone_set_max(divcbinfo.ipi_zone, maxsockets); EVENTHANDLER_REGISTER(maxsockets_change, div_zone_change, NULL, EVENTHANDLER_PRI_ANY); } /* * IPPROTO_DIVERT is not in the real IP protocol number space; this * function should never be called. Just in case, drop any packets. */ void div_input(struct mbuf *m, int off) { ipstat.ips_noproto++; m_freem(m); } /* * Divert a packet by passing it up to the divert socket at port 'port'. * * Setup generic address and protocol structures for div_input routine, * then pass them along with mbuf chain. */ static void divert_packet(struct mbuf *m, int incoming) { struct ip *ip; struct inpcb *inp; struct socket *sa; u_int16_t nport; struct sockaddr_in divsrc; struct m_tag *mtag; mtag = m_tag_find(m, PACKET_TAG_DIVERT, NULL); if (mtag == NULL) { printf("%s: no divert tag\n", __func__); m_freem(m); return; } /* Assure header */ if (m->m_len < sizeof(struct ip) && (m = m_pullup(m, sizeof(struct ip))) == 0) return; ip = mtod(m, struct ip *); /* Delayed checksums are currently not compatible with divert. */ if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { ip->ip_len = ntohs(ip->ip_len); in_delayed_cksum(m); m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; ip->ip_len = htons(ip->ip_len); } /* * Record receive interface address, if any. * But only for incoming packets. */ bzero(&divsrc, sizeof(divsrc)); divsrc.sin_len = sizeof(divsrc); divsrc.sin_family = AF_INET; divsrc.sin_port = divert_cookie(mtag); /* record matching rule */ if (incoming) { struct ifaddr *ifa; /* Sanity check */ M_ASSERTPKTHDR(m); /* Find IP address for receive interface */ TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->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 */ sa = NULL; nport = htons((u_int16_t)divert_info(mtag)); INP_INFO_RLOCK(&divcbinfo); LIST_FOREACH(inp, &divcb, inp_list) { INP_LOCK(inp); /* XXX why does only one socket match? */ if (inp->inp_lport == nport) { sa = inp->inp_socket; SOCKBUF_LOCK(&sa->so_rcv); if (sbappendaddr_locked(&sa->so_rcv, (struct sockaddr *)&divsrc, m, (struct mbuf *)0) == 0) { SOCKBUF_UNLOCK(&sa->so_rcv); sa = NULL; /* force mbuf reclaim below */ } else sorwakeup_locked(sa); INP_UNLOCK(inp); break; } INP_UNLOCK(inp); } INP_INFO_RUNLOCK(&divcbinfo); if (sa == NULL) { m_freem(m); ipstat.ips_noproto++; ipstat.ips_delivered--; } } /* * 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_output(struct socket *so, struct mbuf *m, struct sockaddr_in *sin, struct mbuf *control) { struct m_tag *mtag; struct divert_tag *dt; int error = 0; struct mbuf *options; /* * An mbuf may hasn't come from userland, but we pretend * that it has. */ m->m_pkthdr.rcvif = NULL; m->m_nextpkt = NULL; if (control) m_freem(control); /* XXX */ if ((mtag = m_tag_find(m, PACKET_TAG_DIVERT, NULL)) == NULL) { mtag = m_tag_get(PACKET_TAG_DIVERT, sizeof(struct divert_tag), M_NOWAIT | M_ZERO); if (mtag == NULL) { error = ENOBUFS; goto cantsend; } dt = (struct divert_tag *)(mtag+1); m_tag_prepend(m, mtag); } else dt = (struct divert_tag *)(mtag+1); /* Loopback avoidance and state recovery */ if (sin) { int i; dt->cookie = sin->sin_port; /* * 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); } /* Reinject packet into the system as incoming or outgoing */ if (!sin || sin->sin_addr.s_addr == 0) { struct ip *const ip = mtod(m, struct ip *); struct inpcb *inp; dt->info |= IP_FW_DIVERT_OUTPUT_FLAG; INP_INFO_WLOCK(&divcbinfo); inp = sotoinpcb(so); INP_LOCK(inp); /* * Don't allow both user specified and setsockopt options, * and don't allow packet length sizes that will crash */ if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) || ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) { error = EINVAL; INP_UNLOCK(inp); INP_INFO_WUNLOCK(&divcbinfo); m_freem(m); } else { /* Convert fields to host order for ip_output() */ ip->ip_len = ntohs(ip->ip_len); ip->ip_off = ntohs(ip->ip_off); /* Send packet to output processing */ ipstat.ips_rawout++; /* XXX */ #ifdef MAC mac_inpcb_create_mbuf(inp, m); #endif /* * Get ready to inject the packet into ip_output(). * Just in case socket options were specified on the * divert socket, we duplicate them. This is done * to avoid having to hold the PCB locks over the call * to ip_output(), as doing this results in a number of * lock ordering complexities. * * Note that we set the multicast options argument for * ip_output() to NULL since it should be invariant that * they are not present. */ KASSERT(inp->inp_moptions == NULL, ("multicast options set on a divert socket")); options = NULL; /* * XXXCSJP: It is unclear to me whether or not it makes * sense for divert sockets to have options. However, * for now we will duplicate them with the INP locks * held so we can use them in ip_output() without * requring a reference to the pcb. */ if (inp->inp_options != NULL) { options = m_dup(inp->inp_options, M_DONTWAIT); if (options == NULL) error = ENOBUFS; } INP_UNLOCK(inp); INP_INFO_WUNLOCK(&divcbinfo); if (error == ENOBUFS) { m_freem(m); return (error); } error = ip_output(m, options, NULL, ((so->so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0) | IP_ALLOWBROADCAST | IP_RAWOUTPUT, NULL, NULL); if (options != NULL) m_freem(options); } } else { dt->info |= IP_FW_DIVERT_LOOPBACK_FLAG; 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. */ struct ifaddr *ifa; bzero(sin->sin_zero, sizeof(sin->sin_zero)); sin->sin_port = 0; ifa = ifa_ifwithaddr((struct sockaddr *) sin); if (ifa == NULL) { error = EADDRNOTAVAIL; goto cantsend; } m->m_pkthdr.rcvif = ifa->ifa_ifp; } #ifdef MAC SOCK_LOCK(so); mac_socket_create_mbuf(so, m); SOCK_UNLOCK(so); #endif /* Send packet to input processing via netisr */ netisr_queue(NETISR_IP, m); } return error; cantsend: m_freem(m); return error; } static int div_attach(struct socket *so, int proto, struct thread *td) { struct inpcb *inp; int error; inp = sotoinpcb(so); KASSERT(inp == NULL, ("div_attach: inp != NULL")); 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; INP_INFO_WLOCK(&divcbinfo); error = in_pcballoc(so, &divcbinfo); if (error) { INP_INFO_WUNLOCK(&divcbinfo); return error; } inp = (struct inpcb *)so->so_pcb; INP_INFO_WUNLOCK(&divcbinfo); inp->inp_ip_p = proto; inp->inp_vflag |= INP_IPV4; inp->inp_flags |= INP_HDRINCL; INP_UNLOCK(inp); return 0; } static void div_detach(struct socket *so) { struct inpcb *inp; inp = sotoinpcb(so); KASSERT(inp != NULL, ("div_detach: inp == NULL")); INP_INFO_WLOCK(&divcbinfo); INP_LOCK(inp); in_pcbdetach(inp); in_pcbfree(inp); INP_INFO_WUNLOCK(&divcbinfo); } static int div_bind(struct socket *so, struct sockaddr *nam, struct thread *td) { struct inpcb *inp; int error; inp = sotoinpcb(so); KASSERT(inp != NULL, ("div_bind: inp == NULL")); /* in_pcbbind assumes that nam is a sockaddr_in * and in_pcbbind requires a valid address. Since divert * sockets don't we need to make sure the address is * filled in properly. * XXX -- divert should not be abusing in_pcbind * and should probably have its own family. */ if (nam->sa_family != AF_INET) return EAFNOSUPPORT; ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY; INP_INFO_WLOCK(&divcbinfo); INP_LOCK(inp); error = in_pcbbind(inp, nam, td->td_ucred); INP_UNLOCK(inp); INP_INFO_WUNLOCK(&divcbinfo); return error; } static int div_shutdown(struct socket *so) { struct inpcb *inp; inp = sotoinpcb(so); KASSERT(inp != NULL, ("div_shutdown: inp == NULL")); INP_LOCK(inp); socantsendmore(so); INP_UNLOCK(inp); return 0; } static int div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam, struct mbuf *control, struct thread *td) { /* Packet must have a header (but that's about it) */ if (m->m_len < sizeof (struct ip) && (m = m_pullup(m, sizeof (struct ip))) == 0) { ipstat.ips_toosmall++; m_freem(m); return EINVAL; } /* Send packet */ return div_output(so, m, (struct sockaddr_in *)nam, control); } void div_ctlinput(int cmd, struct sockaddr *sa, void *vip) { struct in_addr faddr; faddr = ((struct sockaddr_in *)sa)->sin_addr; if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY) return; if (PRC_IS_REDIRECT(cmd)) return; } static int div_pcblist(SYSCTL_HANDLER_ARGS) { int error, i, n; struct inpcb *inp, **inp_list; inp_gen_t gencnt; struct xinpgen xig; /* * The process of preparing the TCB list is too time-consuming and * resource-intensive to repeat twice on every request. */ if (req->oldptr == 0) { n = divcbinfo.ipi_count; req->oldidx = 2 * (sizeof xig) + (n + n/8) * sizeof(struct xinpcb); return 0; } if (req->newptr != 0) return EPERM; /* * OK, now we're committed to doing something. */ INP_INFO_RLOCK(&divcbinfo); gencnt = divcbinfo.ipi_gencnt; n = divcbinfo.ipi_count; INP_INFO_RUNLOCK(&divcbinfo); error = sysctl_wire_old_buffer(req, 2 * sizeof(xig) + n*sizeof(struct xinpcb)); if (error != 0) return (error); xig.xig_len = sizeof xig; xig.xig_count = n; xig.xig_gen = gencnt; xig.xig_sogen = so_gencnt; error = SYSCTL_OUT(req, &xig, sizeof xig); if (error) return error; inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK); if (inp_list == 0) return ENOMEM; INP_INFO_RLOCK(&divcbinfo); for (inp = LIST_FIRST(divcbinfo.ipi_listhead), i = 0; inp && i < n; inp = LIST_NEXT(inp, inp_list)) { INP_LOCK(inp); if (inp->inp_gencnt <= gencnt && cr_canseesocket(req->td->td_ucred, inp->inp_socket) == 0) inp_list[i++] = inp; INP_UNLOCK(inp); } INP_INFO_RUNLOCK(&divcbinfo); n = i; error = 0; for (i = 0; i < n; i++) { inp = inp_list[i]; INP_LOCK(inp); if (inp->inp_gencnt <= gencnt) { struct xinpcb xi; bzero(&xi, sizeof(xi)); xi.xi_len = sizeof xi; /* XXX should avoid extra copy */ bcopy(inp, &xi.xi_inp, sizeof *inp); if (inp->inp_socket) sotoxsocket(inp->inp_socket, &xi.xi_socket); INP_UNLOCK(inp); error = SYSCTL_OUT(req, &xi, sizeof xi); } else INP_UNLOCK(inp); } if (!error) { /* * 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. */ INP_INFO_RLOCK(&divcbinfo); xig.xig_gen = divcbinfo.ipi_gencnt; xig.xig_sogen = so_gencnt; xig.xig_count = divcbinfo.ipi_count; INP_INFO_RUNLOCK(&divcbinfo); error = SYSCTL_OUT(req, &xig, sizeof xig); } free(inp_list, M_TEMP); return error; } #ifdef SYSCTL_NODE SYSCTL_NODE(_net_inet, IPPROTO_DIVERT, divert, CTLFLAG_RW, 0, "IPDIVERT"); SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, 0, 0, div_pcblist, "S,xinpcb", "List of active divert sockets"); #endif struct pr_usrreqs div_usrreqs = { .pru_attach = div_attach, .pru_bind = div_bind, .pru_control = in_control, .pru_detach = div_detach, .pru_peeraddr = in_getpeeraddr, .pru_send = div_send, .pru_shutdown = div_shutdown, .pru_sockaddr = in_getsockaddr, .pru_sosetlabel = in_pcbsosetlabel }; struct protosw div_protosw = { .pr_type = SOCK_RAW, .pr_protocol = IPPROTO_DIVERT, .pr_flags = PR_ATOMIC|PR_ADDR, .pr_input = div_input, .pr_ctlinput = div_ctlinput, .pr_ctloutput = ip_ctloutput, .pr_init = div_init, .pr_usrreqs = &div_usrreqs }; static int div_modevent(module_t mod, int type, void *unused) { int err = 0; int n; switch (type) { case MOD_LOAD: /* * Protocol will be initialized by pf_proto_register(). * We don't have to register ip_protox because we are not * a true IP protocol that goes over the wire. */ err = pf_proto_register(PF_INET, &div_protosw); 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. */ INP_INFO_WLOCK(&divcbinfo); n = divcbinfo.ipi_count; if (n != 0) { err = EBUSY; INP_INFO_WUNLOCK(&divcbinfo); break; } ip_divert_ptr = NULL; err = pf_proto_unregister(PF_INET, IPPROTO_DIVERT, SOCK_RAW); INP_INFO_WUNLOCK(&divcbinfo); INP_INFO_LOCK_DESTROY(&divcbinfo); uma_zdestroy(divcbinfo.ipi_zone); break; default: err = EOPNOTSUPP; break; } return err; } static moduledata_t ipdivertmod = { "ipdivert", div_modevent, 0 }; DECLARE_MODULE(ipdivert, ipdivertmod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY); MODULE_DEPEND(dummynet, ipfw, 2, 2, 2); MODULE_VERSION(ipdivert, 1);