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32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
36 #include "opt_inet6.h"
39 #error "IPDIVERT requires INET"
42 #include <sys/param.h>
43 #include <sys/eventhandler.h>
44 #include <sys/kernel.h>
46 #include <sys/malloc.h>
48 #include <sys/module.h>
49 #include <sys/kernel.h>
52 #include <sys/protosw.h>
53 #include <sys/socket.h>
54 #include <sys/socketvar.h>
55 #include <sys/sysctl.h>
59 #include <net/if_var.h>
60 #include <net/netisr.h>
62 #include <netinet/in.h>
63 #include <netinet/in_pcb.h>
64 #include <netinet/in_systm.h>
65 #include <netinet/in_var.h>
66 #include <netinet/ip.h>
67 #include <netinet/ip_var.h>
69 #include <netinet/ip6.h>
70 #include <netinet6/ip6_var.h>
73 #include <netinet/sctp_crc32.h>
76 #include <security/mac/mac_framework.h>
82 * Allocate enough space to hold a full IP packet
84 #define DIVSNDQ (65536 + 100)
85 #define DIVRCVQ (65536 + 100)
88 * Divert sockets work in conjunction with ipfw or other packet filters,
89 * see the divert(4) manpage for features.
90 * Packets are selected by the packet filter and tagged with an
91 * MTAG_IPFW_RULE tag carrying the 'divert port' number (as set by
92 * the packet filter) and information on the matching filter rule for
93 * subsequent reinjection. The divert_port is used to put the packet
94 * on the corresponding divert socket, while the rule number is passed
95 * up (at least partially) as the sin_port in the struct sockaddr.
97 * Packets written to the divert socket carry in sin_addr a
98 * destination address, and in sin_port the number of the filter rule
99 * after which to continue processing.
100 * If the destination address is INADDR_ANY, the packet is treated as
101 * as outgoing and sent to ip_output(); otherwise it is treated as
102 * incoming and sent to ip_input().
103 * Further, sin_zero carries some information on the interface,
104 * which can be used in the reinject -- see comments in the code.
106 * On reinjection, processing in ip_input() and ip_output()
107 * will be exactly the same as for the original packet, except that
108 * packet filter processing will start at the rule number after the one
109 * written in the sin_port (ipfw does not allow a rule #0, so sin_port=0
110 * will apply the entire ruleset to the packet).
113 /* Internal variables. */
114 static VNET_DEFINE(struct inpcbhead, divcb);
115 static VNET_DEFINE(struct inpcbinfo, divcbinfo);
117 #define V_divcb VNET(divcb)
118 #define V_divcbinfo VNET(divcbinfo)
120 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */
121 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */
123 static eventhandler_tag ip_divert_event_tag;
126 * Initialize divert connection block queue.
129 div_zone_change(void *tag)
132 uma_zone_set_max(V_divcbinfo.ipi_zone, maxsockets);
136 div_inpcb_init(void *mem, int size, int flags)
138 struct inpcb *inp = mem;
140 INP_LOCK_INIT(inp, "inp", "divinp");
149 * XXX We don't use the hash list for divert IP, but it's easier to
150 * allocate one-entry hash lists than it is to check all over the
151 * place for hashbase == NULL.
153 in_pcbinfo_init(&V_divcbinfo, "div", &V_divcb, 1, 1, "divcb",
154 div_inpcb_init, IPI_HASHFIELDS_NONE);
158 div_destroy(void *unused __unused)
161 in_pcbinfo_destroy(&V_divcbinfo);
163 VNET_SYSUNINIT(divert, SI_SUB_PROTO_DOMAININIT, SI_ORDER_ANY,
167 * IPPROTO_DIVERT is not in the real IP protocol number space; this
168 * function should never be called. Just in case, drop any packets.
171 div_input(struct mbuf **mp, int *offp, int proto)
173 struct mbuf *m = *mp;
175 KMOD_IPSTAT_INC(ips_noproto);
177 return (IPPROTO_DONE);
181 * Divert a packet by passing it up to the divert socket at port 'port'.
183 * Setup generic address and protocol structures for div_input routine,
184 * then pass them along with mbuf chain.
187 divert_packet(struct mbuf *m, int incoming)
193 struct sockaddr_in divsrc;
196 mtag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
202 if (m->m_len < sizeof(struct ip) &&
203 (m = m_pullup(m, sizeof(struct ip))) == NULL)
205 ip = mtod(m, struct ip *);
207 /* Delayed checksums are currently not compatible with divert. */
208 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
210 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
213 if (m->m_pkthdr.csum_flags & CSUM_SCTP) {
214 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2));
215 m->m_pkthdr.csum_flags &= ~CSUM_SCTP;
218 bzero(&divsrc, sizeof(divsrc));
219 divsrc.sin_len = sizeof(divsrc);
220 divsrc.sin_family = AF_INET;
221 /* record matching rule, in host format */
222 divsrc.sin_port = ((struct ipfw_rule_ref *)(mtag+1))->rulenum;
224 * Record receive interface address, if any.
225 * But only for incoming packets.
234 /* Find IP address for receive interface */
235 ifp = m->m_pkthdr.rcvif;
237 CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
238 if (ifa->ifa_addr->sa_family != AF_INET)
241 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
244 if_addr_runlock(ifp);
247 * Record the incoming interface name whenever we have one.
249 if (m->m_pkthdr.rcvif) {
251 * Hide the actual interface name in there in the
252 * sin_zero array. XXX This needs to be moved to a
253 * different sockaddr type for divert, e.g.
254 * sockaddr_div with multiple fields like
255 * sockaddr_dl. Presently we have only 7 bytes
256 * but that will do for now as most interfaces
257 * are 4 or less + 2 or less bytes for unit.
258 * There is probably a faster way of doing this,
259 * possibly taking it from the sockaddr_dl on the iface.
260 * This solves the problem of a P2P link and a LAN interface
261 * having the same address, which can result in the wrong
262 * interface being assigned to the packet when fed back
263 * into the divert socket. Theoretically if the daemon saves
264 * and re-uses the sockaddr_in as suggested in the man pages,
265 * this iface name will come along for the ride.
266 * (see div_output for the other half of this.)
268 strlcpy(divsrc.sin_zero, m->m_pkthdr.rcvif->if_xname,
269 sizeof(divsrc.sin_zero));
272 /* Put packet on socket queue, if any */
274 nport = htons((u_int16_t)(((struct ipfw_rule_ref *)(mtag+1))->info));
275 INP_INFO_RLOCK(&V_divcbinfo);
276 LIST_FOREACH(inp, &V_divcb, inp_list) {
277 /* XXX why does only one socket match? */
278 if (inp->inp_lport == nport) {
280 sa = inp->inp_socket;
281 SOCKBUF_LOCK(&sa->so_rcv);
282 if (sbappendaddr_locked(&sa->so_rcv,
283 (struct sockaddr *)&divsrc, m,
284 (struct mbuf *)0) == 0) {
285 SOCKBUF_UNLOCK(&sa->so_rcv);
286 sa = NULL; /* force mbuf reclaim below */
288 sorwakeup_locked(sa);
293 INP_INFO_RUNLOCK(&V_divcbinfo);
296 KMOD_IPSTAT_INC(ips_noproto);
297 KMOD_IPSTAT_DEC(ips_delivered);
302 * Deliver packet back into the IP processing machinery.
304 * If no address specified, or address is 0.0.0.0, send to ip_output();
305 * otherwise, send to ip_input() and mark as having been received on
306 * the interface with that address.
309 div_output(struct socket *so, struct mbuf *m, struct sockaddr_in *sin,
310 struct mbuf *control)
312 struct ip *const ip = mtod(m, struct ip *);
314 struct ipfw_rule_ref *dt;
318 * An mbuf may hasn't come from userland, but we pretend
321 m->m_pkthdr.rcvif = NULL;
323 M_SETFIB(m, so->so_fibnum);
326 m_freem(control); /* XXX */
328 mtag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
330 /* this should be normal */
331 mtag = m_tag_alloc(MTAG_IPFW_RULE, 0,
332 sizeof(struct ipfw_rule_ref), M_NOWAIT | M_ZERO);
337 m_tag_prepend(m, mtag);
339 dt = (struct ipfw_rule_ref *)(mtag+1);
341 /* Loopback avoidance and state recovery */
345 /* set the starting point. We provide a non-zero slot,
346 * but a non_matching chain_id to skip that info and use
347 * the rulenum/rule_id.
349 dt->slot = 1; /* dummy, chain_id is invalid */
351 dt->rulenum = sin->sin_port+1; /* host format ? */
354 * Find receive interface with the given name, stuffed
355 * (if it exists) in the sin_zero[] field.
356 * The name is user supplied data so don't trust its size
357 * or that it is zero terminated.
359 for (i = 0; i < sizeof(sin->sin_zero) && sin->sin_zero[i]; i++)
361 if ( i > 0 && i < sizeof(sin->sin_zero))
362 m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
365 /* Reinject packet into the system as incoming or outgoing */
366 if (!sin || sin->sin_addr.s_addr == 0) {
367 struct mbuf *options = NULL;
370 dt->info |= IPFW_IS_DIVERT | IPFW_INFO_OUT;
376 * Don't allow both user specified and setsockopt
377 * options, and don't allow packet length sizes that
380 if ((((ip->ip_hl << 2) != sizeof(struct ip)) &&
381 inp->inp_options != NULL) ||
382 ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) {
389 case IPV6_VERSION >> 4:
391 struct ip6_hdr *const ip6 = mtod(m, struct ip6_hdr *);
393 /* Don't allow packet length sizes that will crash */
394 if (((u_short)ntohs(ip6->ip6_plen) > m->m_pkthdr.len)) {
408 /* Send packet to output processing */
409 KMOD_IPSTAT_INC(ips_rawout); /* XXX */
412 mac_inpcb_create_mbuf(inp, m);
415 * Get ready to inject the packet into ip_output().
416 * Just in case socket options were specified on the
417 * divert socket, we duplicate them. This is done
418 * to avoid having to hold the PCB locks over the call
419 * to ip_output(), as doing this results in a number of
420 * lock ordering complexities.
422 * Note that we set the multicast options argument for
423 * ip_output() to NULL since it should be invariant that
424 * they are not present.
426 KASSERT(inp->inp_moptions == NULL,
427 ("multicast options set on a divert socket"));
429 * XXXCSJP: It is unclear to me whether or not it makes
430 * sense for divert sockets to have options. However,
431 * for now we will duplicate them with the INP locks
432 * held so we can use them in ip_output() without
433 * requring a reference to the pcb.
435 if (inp->inp_options != NULL) {
436 options = m_dup(inp->inp_options, M_NOWAIT);
437 if (options == NULL) {
447 error = ip_output(m, options, NULL,
448 ((so->so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0)
449 | IP_ALLOWBROADCAST | IP_RAWOUTPUT, NULL, NULL);
452 case IPV6_VERSION >> 4:
453 error = ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
460 dt->info |= IPFW_IS_DIVERT | IPFW_INFO_IN;
461 if (m->m_pkthdr.rcvif == NULL) {
463 * No luck with the name, check by IP address.
464 * Clear the port and the ifname to make sure
465 * there are no distractions for ifa_ifwithaddr.
469 bzero(sin->sin_zero, sizeof(sin->sin_zero));
471 ifa = ifa_ifwithaddr((struct sockaddr *) sin);
473 error = EADDRNOTAVAIL;
476 m->m_pkthdr.rcvif = ifa->ifa_ifp;
480 mac_socket_create_mbuf(so, m);
482 /* Send packet to input processing via netisr */
486 * Restore M_BCAST flag when destination address is
487 * broadcast. It is expected by ip_tryforward().
489 if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)))
490 m->m_flags |= M_MCAST;
491 else if (in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif))
492 m->m_flags |= M_BCAST;
493 netisr_queue_src(NETISR_IP, (uintptr_t)so, m);
496 case IPV6_VERSION >> 4:
497 netisr_queue_src(NETISR_IPV6, (uintptr_t)so, m);
514 div_attach(struct socket *so, int proto, struct thread *td)
520 KASSERT(inp == NULL, ("div_attach: inp != NULL"));
522 error = priv_check(td, PRIV_NETINET_DIVERT);
526 error = soreserve(so, div_sendspace, div_recvspace);
529 INP_INFO_WLOCK(&V_divcbinfo);
530 error = in_pcballoc(so, &V_divcbinfo);
532 INP_INFO_WUNLOCK(&V_divcbinfo);
535 inp = (struct inpcb *)so->so_pcb;
536 INP_INFO_WUNLOCK(&V_divcbinfo);
537 inp->inp_ip_p = proto;
538 inp->inp_vflag |= INP_IPV4;
539 inp->inp_flags |= INP_HDRINCL;
545 div_detach(struct socket *so)
550 KASSERT(inp != NULL, ("div_detach: inp == NULL"));
551 INP_INFO_WLOCK(&V_divcbinfo);
555 INP_INFO_WUNLOCK(&V_divcbinfo);
559 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
565 KASSERT(inp != NULL, ("div_bind: inp == NULL"));
566 /* in_pcbbind assumes that nam is a sockaddr_in
567 * and in_pcbbind requires a valid address. Since divert
568 * sockets don't we need to make sure the address is
569 * filled in properly.
570 * XXX -- divert should not be abusing in_pcbind
571 * and should probably have its own family.
573 if (nam->sa_family != AF_INET)
575 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
576 INP_INFO_WLOCK(&V_divcbinfo);
578 INP_HASH_WLOCK(&V_divcbinfo);
579 error = in_pcbbind(inp, nam, td->td_ucred);
580 INP_HASH_WUNLOCK(&V_divcbinfo);
582 INP_INFO_WUNLOCK(&V_divcbinfo);
587 div_shutdown(struct socket *so)
592 KASSERT(inp != NULL, ("div_shutdown: inp == NULL"));
600 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
601 struct mbuf *control, struct thread *td)
604 /* Packet must have a header (but that's about it) */
605 if (m->m_len < sizeof (struct ip) &&
606 (m = m_pullup(m, sizeof (struct ip))) == NULL) {
607 KMOD_IPSTAT_INC(ips_toosmall);
613 return div_output(so, m, (struct sockaddr_in *)nam, control);
617 div_ctlinput(int cmd, struct sockaddr *sa, void *vip)
619 struct in_addr faddr;
621 faddr = ((struct sockaddr_in *)sa)->sin_addr;
622 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
624 if (PRC_IS_REDIRECT(cmd))
629 div_pcblist(SYSCTL_HANDLER_ARGS)
632 struct inpcb *inp, **inp_list;
637 * The process of preparing the TCB list is too time-consuming and
638 * resource-intensive to repeat twice on every request.
640 if (req->oldptr == 0) {
641 n = V_divcbinfo.ipi_count;
642 n += imax(n / 8, 10);
643 req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xinpcb);
647 if (req->newptr != 0)
651 * OK, now we're committed to doing something.
653 INP_INFO_RLOCK(&V_divcbinfo);
654 gencnt = V_divcbinfo.ipi_gencnt;
655 n = V_divcbinfo.ipi_count;
656 INP_INFO_RUNLOCK(&V_divcbinfo);
658 error = sysctl_wire_old_buffer(req,
659 2 * sizeof(xig) + n*sizeof(struct xinpcb));
663 xig.xig_len = sizeof xig;
665 xig.xig_gen = gencnt;
666 xig.xig_sogen = so_gencnt;
667 error = SYSCTL_OUT(req, &xig, sizeof xig);
671 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
672 if (inp_list == NULL)
675 INP_INFO_RLOCK(&V_divcbinfo);
676 for (inp = LIST_FIRST(V_divcbinfo.ipi_listhead), i = 0; inp && i < n;
677 inp = LIST_NEXT(inp, inp_list)) {
679 if (inp->inp_gencnt <= gencnt &&
680 cr_canseeinpcb(req->td->td_ucred, inp) == 0) {
686 INP_INFO_RUNLOCK(&V_divcbinfo);
690 for (i = 0; i < n; i++) {
693 if (inp->inp_gencnt <= gencnt) {
696 in_pcbtoxinpcb(inp, &xi);
698 error = SYSCTL_OUT(req, &xi, sizeof xi);
702 INP_INFO_WLOCK(&V_divcbinfo);
703 for (i = 0; i < n; i++) {
706 if (!in_pcbrele_rlocked(inp))
709 INP_INFO_WUNLOCK(&V_divcbinfo);
713 * Give the user an updated idea of our state.
714 * If the generation differs from what we told
715 * her before, she knows that something happened
716 * while we were processing this request, and it
717 * might be necessary to retry.
719 INP_INFO_RLOCK(&V_divcbinfo);
720 xig.xig_gen = V_divcbinfo.ipi_gencnt;
721 xig.xig_sogen = so_gencnt;
722 xig.xig_count = V_divcbinfo.ipi_count;
723 INP_INFO_RUNLOCK(&V_divcbinfo);
724 error = SYSCTL_OUT(req, &xig, sizeof xig);
726 free(inp_list, M_TEMP);
731 static SYSCTL_NODE(_net_inet, IPPROTO_DIVERT, divert, CTLFLAG_RW, 0,
733 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLTYPE_OPAQUE | CTLFLAG_RD,
734 NULL, 0, div_pcblist, "S,xinpcb", "List of active divert sockets");
737 struct pr_usrreqs div_usrreqs = {
738 .pru_attach = div_attach,
739 .pru_bind = div_bind,
740 .pru_control = in_control,
741 .pru_detach = div_detach,
742 .pru_peeraddr = in_getpeeraddr,
743 .pru_send = div_send,
744 .pru_shutdown = div_shutdown,
745 .pru_sockaddr = in_getsockaddr,
746 .pru_sosetlabel = in_pcbsosetlabel
749 struct protosw div_protosw = {
751 .pr_protocol = IPPROTO_DIVERT,
752 .pr_flags = PR_ATOMIC|PR_ADDR,
753 .pr_input = div_input,
754 .pr_ctlinput = div_ctlinput,
755 .pr_ctloutput = ip_ctloutput,
757 .pr_usrreqs = &div_usrreqs
761 div_modevent(module_t mod, int type, void *unused)
768 * Protocol will be initialized by pf_proto_register().
769 * We don't have to register ip_protox because we are not
770 * a true IP protocol that goes over the wire.
772 err = pf_proto_register(PF_INET, &div_protosw);
775 ip_divert_ptr = divert_packet;
776 ip_divert_event_tag = EVENTHANDLER_REGISTER(maxsockets_change,
777 div_zone_change, NULL, EVENTHANDLER_PRI_ANY);
781 * IPDIVERT may normally not be unloaded because of the
782 * potential race conditions. Tell kldunload we can't be
783 * unloaded unless the unload is forced.
791 * Module ipdivert can only be unloaded if no sockets are
792 * connected. Maybe this can be changed later to forcefully
793 * disconnect any open sockets.
795 * XXXRW: Note that there is a slight race here, as a new
796 * socket open request could be spinning on the lock and then
797 * we destroy the lock.
799 INP_INFO_WLOCK(&V_divcbinfo);
800 if (V_divcbinfo.ipi_count != 0) {
802 INP_INFO_WUNLOCK(&V_divcbinfo);
805 ip_divert_ptr = NULL;
806 err = pf_proto_unregister(PF_INET, IPPROTO_DIVERT, SOCK_RAW);
807 INP_INFO_WUNLOCK(&V_divcbinfo);
811 EVENTHANDLER_DEREGISTER(maxsockets_change, ip_divert_event_tag);
820 static moduledata_t ipdivertmod = {
826 DECLARE_MODULE(ipdivert, ipdivertmod, SI_SUB_PROTO_FIREWALL, SI_ORDER_ANY);
827 MODULE_DEPEND(ipdivert, ipfw, 3, 3, 3);
828 MODULE_VERSION(ipdivert, 1);