/* * 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 1.39 2008/09/13 08:48:42 sephe Exp $ */ #define _IP_VHL #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 #ifdef SMP #include #endif #include #include #include #ifdef SMP #include #endif #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) #define DIV_IS_OUTPUT(sin) ((sin) == NULL || (sin)->sin_addr.s_addr == 0) #define DIV_OUTPUT 0x10000 #define DIV_INPUT 0x20000 /* * 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 ? */ static struct mbuf *ip_divert(struct mbuf *, int, int); /* * 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); ip_divert_p = ip_divert; } /* * 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); } struct lwkt_port * div_soport(struct socket *so, struct sockaddr *nam, struct mbuf **mptr, int req) { struct sockaddr_in *sin; struct mbuf *m; int dir; /* Except for send(), everything happens on CPU0 */ if (req != PRU_SEND) return cpu0_soport(so, nam, mptr, req); sin = (struct sockaddr_in *)nam; m = *mptr; M_ASSERTPKTHDR(m); m->m_pkthdr.rcvif = NULL; dir = DIV_IS_OUTPUT(sin) ? IP_MPORT_OUT : IP_MPORT_IN; if (sin != NULL) { int i; /* * Try locating the interface, if we originally had one. * This is done even for outgoing packets, since for a * forwarded packet, there must be an interface attached. * * 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); } if (dir == IP_MPORT_IN && 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. * * Be careful not to trash sin->sin_port; it will * be used later in div_output(). */ struct ifaddr *ifa; u_short sin_port; bzero(sin->sin_zero, sizeof(sin->sin_zero)); sin_port = sin->sin_port; /* save */ sin->sin_port = 0; ifa = ifa_ifwithaddr((struct sockaddr *)sin); if (ifa == NULL) { m_freem(m); *mptr = NULL; return NULL; } sin->sin_port = sin_port; /* restore */ m->m_pkthdr.rcvif = ifa->ifa_ifp; } return ip_mport(mptr, dir); } /* * 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 div_packet(struct mbuf *m, int incoming, int port) { struct sockaddr_in divsrc = { sizeof divsrc, AF_INET }; struct inpcb *inp; struct socket *sa; struct m_tag *mtag; struct divert_info *divinfo; u_int16_t nport; /* Locate the divert info */ mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); divinfo = m_tag_data(mtag); divsrc.sin_port = divinfo->skipto; /* * Record receive interface address, if any. * But only for incoming packets. */ divsrc.sin_addr.s_addr = 0; if (incoming) { struct ifaddr_container *ifac; /* Find IP address for receive interface */ TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid], ifa_link) { struct ifaddr *ifa = ifac->ifa; 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.) */ ksnprintf(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 (ssb_appendaddr(&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--; } } #ifdef SMP static void div_packet_handler(struct netmsg *nmsg) { struct netmsg_packet *nmp; struct lwkt_msg *msg; struct mbuf *m; int port, incoming = 0; nmp = (struct netmsg_packet *)nmsg; m = nmp->nm_packet; msg = &nmsg->nm_lmsg; port = msg->u.ms_result32 & 0xffff; if (msg->u.ms_result32 & DIV_INPUT) incoming = 1; div_packet(m, incoming, port); } #endif /* SMP */ static void divert_packet(struct mbuf *m, int incoming) { struct m_tag *mtag; struct divert_info *divinfo; int port; M_ASSERTPKTHDR(m); /* Assure header */ if (m->m_len < sizeof(struct ip) && (m = m_pullup(m, sizeof(struct ip))) == NULL) return; mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); KASSERT(mtag != NULL, ("%s no divert tag!", __func__)); divinfo = m_tag_data(mtag); port = divinfo->port; KASSERT(port != 0, ("%s: port=0", __func__)); #ifdef SMP if (mycpuid != 0) { struct netmsg_packet *nmp; struct lwkt_msg *msg; nmp = &m->m_hdr.mh_netmsg; netmsg_init(&nmp->nm_netmsg, &netisr_apanic_rport, 0, div_packet_handler); nmp->nm_packet = m; msg = &nmp->nm_netmsg.nm_lmsg; msg->u.ms_result32 = port; /* port is 16bits */ if (incoming) msg->u.ms_result32 |= DIV_INPUT; else msg->u.ms_result32 |= DIV_OUTPUT; lwkt_sendmsg(cpu_portfn(0), &nmp->nm_netmsg.nm_lmsg); } else #endif div_packet(m, incoming, port); } /* * 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; struct divert_info *divinfo; if (control) m_freem(control); /* XXX */ /* * 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(*divinfo), MB_DONTWAIT); if (mtag == NULL) { error = ENOBUFS; goto cantsend; } m_tag_prepend(m, mtag); /* Loopback avoidance and state recovery */ divinfo = m_tag_data(mtag); if (sin) divinfo->skipto = sin->sin_port; else divinfo->skipto = 0; /* Reinject packet into the system as incoming or outgoing */ if (DIV_IS_OUTPUT(sin)) { 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) { 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, NULL, NULL, (so->so_options & SO_DONTROUTE) | IP_ALLOWBROADCAST | IP_RAWOUTPUT, NULL, NULL); } else { 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; error = in_pcballoc(so, &divcbinfo); 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) { int error; /* * 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(so->so_pcb, nam, td); } 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) { /* Length check already done in ip_mport() */ KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf")); /* 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 = { .pru_abort = div_abort, .pru_accept = pru_accept_notsupp, .pru_attach = div_attach, .pru_bind = div_bind, .pru_connect = pru_connect_notsupp, .pru_connect2 = pru_connect2_notsupp, .pru_control = in_control, .pru_detach = div_detach, .pru_disconnect = div_disconnect, .pru_listen = pru_listen_notsupp, .pru_peeraddr = in_setpeeraddr, .pru_rcvd = pru_rcvd_notsupp, .pru_rcvoob = pru_rcvoob_notsupp, .pru_send = div_send, .pru_sense = pru_sense_null, .pru_shutdown = div_shutdown, .pru_sockaddr = in_setsockaddr, .pru_sosend = sosend, .pru_soreceive = soreceive, .pru_sopoll = sopoll }; static struct mbuf * ip_divert_out(struct mbuf *m, int tee) { struct mbuf *clone = NULL; struct ip *ip = mtod(m, struct ip *); /* Clone packet if we're doing a 'tee' */ if (tee) clone = m_dup(m, MB_DONTWAIT); /* * XXX * delayed checksums are not currently compatible * with divert sockets. */ if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) { in_delayed_cksum(m); m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA; } /* Restore packet header fields to original values */ ip->ip_len = htons(ip->ip_len); ip->ip_off = htons(ip->ip_off); /* Deliver packet to divert input routine */ divert_packet(m, 0); /* If 'tee', continue with original packet */ return clone; } static struct mbuf * ip_divert_in(struct mbuf *m, int tee) { struct mbuf *clone = NULL; struct ip *ip = mtod(m, struct ip *); struct m_tag *mtag; if (ip->ip_off & (IP_MF | IP_OFFMASK)) { const struct divert_info *divinfo; u_short frag_off; int hlen; /* * Only trust divert info in the fragment * at offset 0. */ frag_off = ip->ip_off << 3; if (frag_off != 0) { mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); m_tag_delete(m, mtag); } /* * Attempt reassembly; if it succeeds, proceed. * ip_reass() will return a different mbuf. */ m = ip_reass(m); if (m == NULL) return NULL; ip = mtod(m, struct ip *); /* Caller need to redispatch the packet, if it is for us */ m->m_pkthdr.fw_flags |= FW_MBUF_REDISPATCH; /* * Get the header length of the reassembled * packet */ hlen = IP_VHL_HL(ip->ip_vhl) << 2; /* * Restore original checksum before diverting * packet */ ip->ip_len += hlen; ip->ip_len = htons(ip->ip_len); ip->ip_off = htons(ip->ip_off); ip->ip_sum = 0; if (hlen == sizeof(struct ip)) ip->ip_sum = in_cksum_hdr(ip); else ip->ip_sum = in_cksum(m, hlen); ip->ip_off = ntohs(ip->ip_off); ip->ip_len = ntohs(ip->ip_len); /* * Only use the saved divert info */ mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL); if (mtag == NULL) { /* Wrongly configured ipfw */ kprintf("ip_input no divert info\n"); m_freem(m); return NULL; } divinfo = m_tag_data(mtag); tee = divinfo->tee; } /* * Divert or tee packet to the divert protocol if * required. */ /* Clone packet if we're doing a 'tee' */ if (tee) clone = m_dup(m, MB_DONTWAIT); /* * Restore packet header fields to original * values */ ip->ip_len = htons(ip->ip_len); ip->ip_off = htons(ip->ip_off); /* Deliver packet to divert input routine */ divert_packet(m, 1); /* Catch invalid reference */ m = NULL; ip = NULL; ipstat.ips_delivered++; /* If 'tee', continue with original packet */ if (clone != NULL) { /* * Complete processing of the packet. * XXX Better safe than sorry, remove the DIVERT tag. */ mtag = m_tag_find(clone, PACKET_TAG_IPFW_DIVERT, NULL); KKASSERT(mtag != NULL); m_tag_delete(clone, mtag); } return clone; } static struct mbuf * ip_divert(struct mbuf *m, int tee, int incoming) { struct mbuf *ret; if (incoming) ret = ip_divert_in(m, tee); else ret = ip_divert_out(m, tee); return ret; }