/* * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 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. * * $FreeBSD$ */ #include "opt_inet.h" #include "opt_ipfw.h" #include "opt_ipdivert.h" #include "opt_ipsec.h" #include "opt_mac.h" #ifndef INET #error "IPDIVERT requires INET." #endif #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 ? */ /* Optimization: have this preinitialized */ static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET }; /* * Initialize divert connection block queue. */ void div_init(void) { INP_INFO_LOCK_INIT(&divcbinfo, "div"); LIST_INIT(&divcb); divcbinfo.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.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask); divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask); divcbinfo.ipi_zone = uma_zcreate("divcb", sizeof(struct inpcb), NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); uma_zone_set_max(divcbinfo.ipi_zone, maxsockets); } /* * 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. */ void divert_packet(struct mbuf *m, int incoming, int port, int rule) { struct ip *ip; struct inpcb *inp; struct socket *sa; u_int16_t nport; /* Sanity check */ KASSERT(port != 0, ("%s: port=0", __func__)); divsrc.sin_port = rule; /* record matching rule */ /* Assure header */ if (m->m_len < sizeof(struct ip) && (m = m_pullup(m, sizeof(struct ip))) == 0) return; ip = mtod(m, struct ip *); /* * Record receive interface address, if any. * But only for incoming packets. */ divsrc.sin_addr.s_addr = 0; if (incoming) { struct ifaddr *ifa; /* Sanity check */ KASSERT((m->m_flags & M_PKTHDR), ("%s: !PKTHDR", __func__)); /* Find IP address for receive interface */ TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) { if (ifa->ifa_addr == NULL) continue; 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. */ bzero(&divsrc.sin_zero, sizeof(divsrc.sin_zero)); 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.) */ snprintf(divsrc.sin_zero, sizeof(divsrc.sin_zero), "%s%d", m->m_pkthdr.rcvif->if_name, m->m_pkthdr.rcvif->if_unit); } /* Put packet on socket queue, if any */ sa = NULL; nport = htons((u_int16_t)port); LIST_FOREACH(inp, &divcb, inp_list) { if (inp->inp_lport == nport) sa = inp->inp_socket; } if (sa) { if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m, (struct mbuf *)0) == 0) m_freem(m); else sorwakeup(sa); } else { 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) { int error = 0; struct m_hdr divert_tag; /* * Prepare the tag for divert info. Note that a packet * with a 0 tag in mh_data is effectively untagged, * so we could optimize that case. */ divert_tag.mh_type = MT_TAG; divert_tag.mh_flags = PACKET_TAG_DIVERT; divert_tag.mh_next = m; divert_tag.mh_data = 0; /* the matching rule # */ m->m_pkthdr.rcvif = NULL; /* XXX is it necessary ? */ #ifdef MAC mac_create_mbuf_from_socket(so, m); #endif if (control) m_freem(control); /* XXX */ /* Loopback avoidance and state recovery */ if (sin) { int i; divert_tag.mh_data = (caddr_t)(uintptr_t)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 inpcb *const inp = sotoinpcb(so); struct ip *const ip = mtod(m, struct ip *); /* * 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; goto cantsend; } /* 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 */ error = ip_output((struct mbuf *)&divert_tag, inp->inp_options, &inp->inp_route, (so->so_options & SO_DONTROUTE) | IP_ALLOWBROADCAST | IP_RAWOUTPUT, inp->inp_moptions, NULL); } else { 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; } /* Send packet to input processing */ ip_input((struct mbuf *)&divert_tag); } 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, s; inp = sotoinpcb(so); if (inp) panic("div_attach"); if (td && (error = suser(td)) != 0) return error; error = soreserve(so, div_sendspace, div_recvspace); if (error) return error; s = splnet(); error = in_pcballoc(so, &divcbinfo, td); splx(s); if (error) return error; inp = (struct inpcb *)so->so_pcb; inp->inp_ip_p = proto; inp->inp_vflag |= INP_IPV4; inp->inp_flags |= INP_HDRINCL; /* The socket is always "connected" because we always know "where" to send the packet */ so->so_state |= SS_ISCONNECTED; return 0; } static int div_detach(struct socket *so) { struct inpcb *inp; inp = sotoinpcb(so); if (inp == 0) panic("div_detach"); in_pcbdetach(inp); return 0; } static int div_abort(struct socket *so) { soisdisconnected(so); return div_detach(so); } static int div_disconnect(struct socket *so) { if ((so->so_state & SS_ISCONNECTED) == 0) return ENOTCONN; return div_abort(so); } static int div_bind(struct socket *so, struct sockaddr *nam, struct thread *td) { struct inpcb *inp; int s; int error; s = splnet(); inp = sotoinpcb(so); /* 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) error = EAFNOSUPPORT; else { ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY; error = in_pcbbind(inp, nam, td); } splx(s); return error; } static int div_shutdown(struct socket *so) { socantsendmore(so); 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); } static int div_pcblist(SYSCTL_HANDLER_ARGS) { int error, i, n, s; 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. */ s = splnet(); gencnt = divcbinfo.ipi_gencnt; n = divcbinfo.ipi_count; splx(s); 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; s = splnet(); for (inp = LIST_FIRST(divcbinfo.listhead), i = 0; inp && i < n; inp = LIST_NEXT(inp, inp_list)) { if (inp->inp_gencnt <= gencnt && !prison_xinpcb(req->td, inp)) inp_list[i++] = inp; } splx(s); n = i; error = 0; for (i = 0; i < n; i++) { inp = inp_list[i]; if (inp->inp_gencnt <= gencnt) { struct xinpcb 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); error = SYSCTL_OUT(req, &xi, sizeof xi); } } 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. */ s = splnet(); xig.xig_gen = divcbinfo.ipi_gencnt; xig.xig_sogen = so_gencnt; xig.xig_count = divcbinfo.ipi_count; splx(s); error = SYSCTL_OUT(req, &xig, sizeof xig); } free(inp_list, M_TEMP); return error; } /* * This is the wrapper function for in_setsockaddr. We just pass down * the pcbinfo for in_setpeeraddr to lock. */ static int div_sockaddr(struct socket *so, struct sockaddr **nam) { return (in_setsockaddr(so, nam, &divcbinfo)); } /* * This is the wrapper function for in_setpeeraddr. We just pass down * the pcbinfo for in_setpeeraddr to lock. */ static int div_peeraddr(struct socket *so, struct sockaddr **nam) { return (in_setpeeraddr(so, nam, &divcbinfo)); } SYSCTL_DECL(_net_inet_divert); SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, 0, 0, div_pcblist, "S,xinpcb", "List of active divert sockets"); struct pr_usrreqs div_usrreqs = { div_abort, pru_accept_notsupp, div_attach, div_bind, pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach, div_disconnect, pru_listen_notsupp, div_peeraddr, pru_rcvd_notsupp, pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown, div_sockaddr, sosend, soreceive, sopoll };