/* * 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" #ifndef INET #error "IPDIVERT requires INET." #endif #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) /* * A 16 bit cookie is passed to and from the user process. * The user process can send it back to help the caller know * something about where the packet originally came from. * * In the case of ipfw, then the cookie is the rule that sent * us here. On reinjection is is the rule after which processing * should continue. Leaving it the same will make processing start * at the rule number after that which sent it here. Setting it to * 0 will restart processing at the beginning. * * For divert_packet(), ip_divert_cookie is an input value only. * For div_output(), ip_divert_cookie is an output value only. */ u_int16_t ip_divert_cookie; /* 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 }; /* Internal functions */ static int div_output(struct socket *so, struct mbuf *m, struct sockaddr *addr, struct mbuf *control); /* * Initialize divert connection block queue. */ void div_init(void) { 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 = 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, int off, int proto) { 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 ip *ip; struct inpcb *inp; struct socket *sa; u_int16_t nport; /* Sanity check */ KASSERT(port != 0, ("%s: port=0", __FUNCTION__)); /* Record and reset divert cookie */ divsrc.sin_port = ip_divert_cookie; ip_divert_cookie = 0; /* 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", __FUNCTION__)); /* Find IP address for receive interface */ for (ifa = m->m_pkthdr.rcvif->if_addrhead.tqh_first; ifa != NULL; ifa = ifa->ifa_link.tqe_next) { 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); for (inp = divcb.lh_first; inp != NULL; inp = inp->inp_list.le_next) { 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(so, m, addr, control) struct socket *so; register struct mbuf *m; struct sockaddr *addr; struct mbuf *control; { register struct inpcb *const inp = sotoinpcb(so); register struct ip *const ip = mtod(m, struct ip *); struct sockaddr_in *sin = (struct sockaddr_in *)addr; int error = 0; if (control) m_freem(control); /* XXX */ /* Loopback avoidance and state recovery */ if (sin) { int len = 0; char *c = sin->sin_zero; ip_divert_cookie = sin->sin_port; /* * Find receive interface with the given name or IP address. * The name is user supplied data so don't trust it's size or * that it is zero terminated. The name has priority. * We are presently assuming that the sockaddr_in * has not been replaced by a sockaddr_div, so we limit it * to 16 bytes in total. the name is stuffed (if it exists) * in the sin_zero[] field. */ while (*c++ && (len++ < sizeof(sin->sin_zero))); if ((len > 0) && (len < sizeof(sin->sin_zero))) m->m_pkthdr.rcvif = ifunit(sin->sin_zero); } else { ip_divert_cookie = 0; } /* Reinject packet into the system as incoming or outgoing */ if (!sin || sin->sin_addr.s_addr == 0) { /* * 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() */ NTOHS(ip->ip_len); 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); } else { struct ifaddr *ifa; /* If no luck with the name above. check by IP address. */ if (m->m_pkthdr.rcvif == NULL) { /* * Make sure there are no distractions * for ifa_ifwithaddr. Clear the port and the ifname. * Maybe zap all 8 bytes at once using a 64bit write? */ bzero(sin->sin_zero, sizeof(sin->sin_zero)); /* *((u_int64_t *)sin->sin_zero) = 0; */ /* XXX ?? */ sin->sin_port = 0; if (!(ifa = ifa_ifwithaddr((struct sockaddr *) sin))) { error = EADDRNOTAVAIL; goto cantsend; } m->m_pkthdr.rcvif = ifa->ifa_ifp; } /* Send packet to input processing */ ip_input(m); } /* paranoid: Reset for next time (and other packets) */ /* almost definitly already done in the ipfw filter but.. */ ip_divert_cookie = 0; return error; cantsend: m_freem(m); ip_divert_cookie = 0; return error; } static int div_attach(struct socket *so, int proto, struct proc *p) { struct inpcb *inp; int error, s; inp = sotoinpcb(so); if (inp) panic("div_attach"); if (p && (error = suser(p)) != 0) return error; error = soreserve(so, div_sendspace, div_recvspace); if (error) return error; s = splnet(); error = in_pcballoc(so, &divcbinfo, p); splx(s); if (error) return error; inp = (struct inpcb *)so->so_pcb; inp->inp_ip_p = proto; inp->inp_flags |= INP_HDRINCL; /* The socket is always "connected" because we always know "where" to send the packet */ so->so_state |= SS_ISCONNECTED; #ifdef IPSEC error = ipsec_init_policy(so, &inp->inp_sp); if (error != 0) { in_pcbdetach(inp); return error; } #endif /*IPSEC*/ 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 proc *p) { struct inpcb *inp; int s; int error; s = splnet(); inp = sotoinpcb(so); error = in_pcbbind(inp, nam, p); splx(s); return 0; } 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 proc *p) { /* 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, nam, control); } 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 };