/* * 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: src/sys/netinet/ip_divert.c,v 1.42.2.6 2003/01/23 21:06:45 sam Exp $ * $DragonFly: src/sys/netinet/ip_divert.c,v 1.25 2005/06/17 19:12:20 dillon Exp $ */ #include "opt_inet.h" #include "opt_ipfw.h" #include "opt_ipdivert.h" #include "opt_ipsec.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 /* * 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 inpcbinfo divcbinfo; static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */ static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */ /* * Initialize divert connection block queue. */ void div_init(void) { in_pcbinfo_init(&divcbinfo); /* * 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.wildcardhashbase = hashinit(1, M_PCB, &divcbinfo.wildcardhashmask); divcbinfo.ipi_zone = zinit("divcb", sizeof(struct inpcb), maxsockets, ZONE_INTERRUPT, 0); } /* * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets * with that protocol number to enter the system from the outside. */ void div_input(struct mbuf *m, ...) { 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) { struct sockaddr_in divsrc = { sizeof divsrc, AF_INET }; struct ip *ip; struct inpcb *inp; struct socket *sa; struct m_tag *mtag; u_int16_t nport; /* Sanity check */ KASSERT(port != 0, ("%s: port=0", __func__)); if ((mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL)) != NULL) divsrc.sin_port = *(u_int16_t *)m_tag_data(mtag); else divsrc.sin_port = 0; /* Assure header */ if (m->m_len < sizeof(struct ip) && (m = m_pullup(m, sizeof(struct ip))) == NULL) 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. */ 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, m->m_pkthdr.rcvif->if_xname); } /* Put packet on socket queue, if any */ sa = NULL; nport = htons((u_int16_t)port); LIST_FOREACH(inp, &divcbinfo.pcblisthead, inp_list) { if (inp->inp_flags & INP_PLACEMARKER) continue; if (inp->inp_lport == nport) sa = inp->inp_socket; } if (sa) { if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m, (struct mbuf *)NULL) == 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_tag *mtag; /* * 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. */ mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT, sizeof(u_int16_t), M_NOWAIT); if (mtag == NULL) { error = ENOBUFS; goto cantsend; } m_tag_prepend(m, mtag); m->m_pkthdr.rcvif = NULL; /* XXX is it necessary ? */ if (control) m_freem(control); /* XXX */ /* Loopback avoidance and state recovery */ if (sin) { int i; *(u_int16_t *)m_tag_data(mtag) = 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; sin->sin_zero[i] && i < sizeof sin->sin_zero; i++) ; if ( i > 0 && i < sizeof sin->sin_zero) m->m_pkthdr.rcvif = ifunit(sin->sin_zero); } else { *(u_int16_t *)m_tag_data(mtag) = 0; } /* Reinject packet into the system as incoming or outgoing */ if (!sin || sin->sin_addr.s_addr == 0) { struct inpcb *const inp = so->so_pcb; 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(m, 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; } ip_input(m); } return error; cantsend: m_freem(m); return error; } static int div_attach(struct socket *so, int proto, struct pru_attach_info *ai) { struct inpcb *inp; int error; inp = so->so_pcb; if (inp) panic("div_attach"); if ((error = suser_cred(ai->p_ucred, NULL_CRED_OKAY)) != 0) return error; error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit); if (error) return error; crit_enter(); error = in_pcballoc(so, &divcbinfo); crit_exit(); 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 = so->so_pcb; if (inp == NULL) 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)) return ENOTCONN; return div_abort(so); } static int div_bind(struct socket *so, struct sockaddr *nam, struct thread *td) { struct inpcb *inp; int error; crit_enter(); inp = so->so_pcb; /* 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); } crit_exit(); 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))) == NULL) { ipstat.ips_toosmall++; m_freem(m); return EINVAL; } /* Send packet */ return div_output(so, m, (struct sockaddr_in *)nam, control); } SYSCTL_DECL(_net_inet_divert); SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 0, in_pcblist_global, "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, in_setpeeraddr, pru_rcvd_notsupp, pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown, in_setsockaddr, sosend, soreceive, sopoll };