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30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
34 #include "opt_inet6.h"
37 #error "IPDIVERT requires INET"
40 #include <sys/param.h>
41 #include <sys/eventhandler.h>
42 #include <sys/kernel.h>
44 #include <sys/malloc.h>
46 #include <sys/module.h>
47 #include <sys/kernel.h>
50 #include <sys/protosw.h>
51 #include <sys/socket.h>
52 #include <sys/socketvar.h>
53 #include <sys/sysctl.h>
57 #include <net/if_var.h>
58 #include <net/netisr.h>
60 #include <netinet/in.h>
61 #include <netinet/in_pcb.h>
62 #include <netinet/in_systm.h>
63 #include <netinet/in_var.h>
64 #include <netinet/ip.h>
65 #include <netinet/ip_var.h>
67 #include <netinet/ip6.h>
68 #include <netinet6/ip6_var.h>
71 #include <netinet/sctp_crc32.h>
74 #include <security/mac/mac_framework.h>
81 * Allocate enough space to hold a full IP packet
83 #define DIVSNDQ (65536 + 100)
84 #define DIVRCVQ (65536 + 100)
87 * Divert sockets work in conjunction with ipfw or other packet filters,
88 * see the divert(4) manpage for features.
89 * Packets are selected by the packet filter and tagged with an
90 * MTAG_IPFW_RULE tag carrying the 'divert port' number (as set by
91 * the packet filter) and information on the matching filter rule for
92 * subsequent reinjection. The divert_port is used to put the packet
93 * on the corresponding divert socket, while the rule number is passed
94 * up (at least partially) as the sin_port in the struct sockaddr.
96 * Packets written to the divert socket carry in sin_addr a
97 * destination address, and in sin_port the number of the filter rule
98 * after which to continue processing.
99 * If the destination address is INADDR_ANY, the packet is treated as
100 * as outgoing and sent to ip_output(); otherwise it is treated as
101 * incoming and sent to ip_input().
102 * Further, sin_zero carries some information on the interface,
103 * which can be used in the reinject -- see comments in the code.
105 * On reinjection, processing in ip_input() and ip_output()
106 * will be exactly the same as for the original packet, except that
107 * packet filter processing will start at the rule number after the one
108 * written in the sin_port (ipfw does not allow a rule #0, so sin_port=0
109 * will apply the entire ruleset to the packet).
112 /* Internal variables. */
113 static VNET_DEFINE(struct inpcbhead, divcb);
114 static VNET_DEFINE(struct inpcbinfo, divcbinfo);
116 #define V_divcb VNET(divcb)
117 #define V_divcbinfo VNET(divcbinfo)
119 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */
120 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */
122 static eventhandler_tag ip_divert_event_tag;
125 * Initialize divert connection block queue.
128 div_zone_change(void *tag)
131 uma_zone_set_max(V_divcbinfo.ipi_zone, maxsockets);
135 div_inpcb_init(void *mem, int size, int flags)
137 struct inpcb *inp = mem;
139 INP_LOCK_INIT(inp, "inp", "divinp");
144 div_inpcb_fini(void *mem, int size)
146 struct inpcb *inp = mem;
148 INP_LOCK_DESTROY(inp);
156 * XXX We don't use the hash list for divert IP, but it's easier to
157 * allocate one-entry hash lists than it is to check all over the
158 * place for hashbase == NULL.
160 in_pcbinfo_init(&V_divcbinfo, "div", &V_divcb, 1, 1, "divcb",
161 div_inpcb_init, div_inpcb_fini, UMA_ZONE_NOFREE,
162 IPI_HASHFIELDS_NONE);
169 in_pcbinfo_destroy(&V_divcbinfo);
173 * IPPROTO_DIVERT is not in the real IP protocol number space; this
174 * function should never be called. Just in case, drop any packets.
177 div_input(struct mbuf *m, int off)
180 KMOD_IPSTAT_INC(ips_noproto);
185 * Divert a packet by passing it up to the divert socket at port 'port'.
187 * Setup generic address and protocol structures for div_input routine,
188 * then pass them along with mbuf chain.
191 divert_packet(struct mbuf *m, int incoming)
197 struct sockaddr_in divsrc;
200 mtag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
206 if (m->m_len < sizeof(struct ip) &&
207 (m = m_pullup(m, sizeof(struct ip))) == 0)
209 ip = mtod(m, struct ip *);
211 /* Delayed checksums are currently not compatible with divert. */
212 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
214 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
217 if (m->m_pkthdr.csum_flags & CSUM_SCTP) {
218 sctp_delayed_cksum(m, (uint32_t)(ip->ip_hl << 2));
219 m->m_pkthdr.csum_flags &= ~CSUM_SCTP;
222 bzero(&divsrc, sizeof(divsrc));
223 divsrc.sin_len = sizeof(divsrc);
224 divsrc.sin_family = AF_INET;
225 /* record matching rule, in host format */
226 divsrc.sin_port = ((struct ipfw_rule_ref *)(mtag+1))->rulenum;
228 * Record receive interface address, if any.
229 * But only for incoming packets.
238 /* Find IP address for receive interface */
239 ifp = m->m_pkthdr.rcvif;
241 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
242 if (ifa->ifa_addr->sa_family != AF_INET)
245 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
248 if_addr_runlock(ifp);
251 * Record the incoming interface name whenever we have one.
253 if (m->m_pkthdr.rcvif) {
255 * Hide the actual interface name in there in the
256 * sin_zero array. XXX This needs to be moved to a
257 * different sockaddr type for divert, e.g.
258 * sockaddr_div with multiple fields like
259 * sockaddr_dl. Presently we have only 7 bytes
260 * but that will do for now as most interfaces
261 * are 4 or less + 2 or less bytes for unit.
262 * There is probably a faster way of doing this,
263 * possibly taking it from the sockaddr_dl on the iface.
264 * This solves the problem of a P2P link and a LAN interface
265 * having the same address, which can result in the wrong
266 * interface being assigned to the packet when fed back
267 * into the divert socket. Theoretically if the daemon saves
268 * and re-uses the sockaddr_in as suggested in the man pages,
269 * this iface name will come along for the ride.
270 * (see div_output for the other half of this.)
272 strlcpy(divsrc.sin_zero, m->m_pkthdr.rcvif->if_xname,
273 sizeof(divsrc.sin_zero));
276 /* Put packet on socket queue, if any */
278 nport = htons((u_int16_t)(((struct ipfw_rule_ref *)(mtag+1))->info));
279 INP_INFO_RLOCK(&V_divcbinfo);
280 LIST_FOREACH(inp, &V_divcb, inp_list) {
281 /* XXX why does only one socket match? */
282 if (inp->inp_lport == nport) {
284 sa = inp->inp_socket;
285 SOCKBUF_LOCK(&sa->so_rcv);
286 if (sbappendaddr_locked(&sa->so_rcv,
287 (struct sockaddr *)&divsrc, m,
288 (struct mbuf *)0) == 0) {
289 SOCKBUF_UNLOCK(&sa->so_rcv);
290 sa = NULL; /* force mbuf reclaim below */
292 sorwakeup_locked(sa);
297 INP_INFO_RUNLOCK(&V_divcbinfo);
300 KMOD_IPSTAT_INC(ips_noproto);
301 KMOD_IPSTAT_DEC(ips_delivered);
306 * Deliver packet back into the IP processing machinery.
308 * If no address specified, or address is 0.0.0.0, send to ip_output();
309 * otherwise, send to ip_input() and mark as having been received on
310 * the interface with that address.
313 div_output(struct socket *so, struct mbuf *m, struct sockaddr_in *sin,
314 struct mbuf *control)
316 struct ip *const ip = mtod(m, struct ip *);
318 struct ipfw_rule_ref *dt;
322 * An mbuf may hasn't come from userland, but we pretend
325 m->m_pkthdr.rcvif = NULL;
327 M_SETFIB(m, so->so_fibnum);
330 m_freem(control); /* XXX */
332 mtag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
334 /* this should be normal */
335 mtag = m_tag_alloc(MTAG_IPFW_RULE, 0,
336 sizeof(struct ipfw_rule_ref), M_NOWAIT | M_ZERO);
341 m_tag_prepend(m, mtag);
343 dt = (struct ipfw_rule_ref *)(mtag+1);
345 /* Loopback avoidance and state recovery */
349 /* set the starting point. We provide a non-zero slot,
350 * but a non_matching chain_id to skip that info and use
351 * the rulenum/rule_id.
353 dt->slot = 1; /* dummy, chain_id is invalid */
355 dt->rulenum = sin->sin_port+1; /* host format ? */
358 * Find receive interface with the given name, stuffed
359 * (if it exists) in the sin_zero[] field.
360 * The name is user supplied data so don't trust its size
361 * or that it is zero terminated.
363 for (i = 0; i < sizeof(sin->sin_zero) && sin->sin_zero[i]; i++)
365 if ( i > 0 && i < sizeof(sin->sin_zero))
366 m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
369 /* Reinject packet into the system as incoming or outgoing */
370 if (!sin || sin->sin_addr.s_addr == 0) {
371 struct mbuf *options = NULL;
374 dt->info |= IPFW_IS_DIVERT | IPFW_INFO_OUT;
380 * Don't allow both user specified and setsockopt
381 * options, and don't allow packet length sizes that
384 if ((((ip->ip_hl << 2) != sizeof(struct ip)) &&
385 inp->inp_options != NULL) ||
386 ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) {
393 case IPV6_VERSION >> 4:
395 struct ip6_hdr *const ip6 = mtod(m, struct ip6_hdr *);
397 /* Don't allow packet length sizes that will crash */
398 if (((u_short)ntohs(ip6->ip6_plen) > m->m_pkthdr.len)) {
412 /* Send packet to output processing */
413 KMOD_IPSTAT_INC(ips_rawout); /* XXX */
416 mac_inpcb_create_mbuf(inp, m);
419 * Get ready to inject the packet into ip_output().
420 * Just in case socket options were specified on the
421 * divert socket, we duplicate them. This is done
422 * to avoid having to hold the PCB locks over the call
423 * to ip_output(), as doing this results in a number of
424 * lock ordering complexities.
426 * Note that we set the multicast options argument for
427 * ip_output() to NULL since it should be invariant that
428 * they are not present.
430 KASSERT(inp->inp_moptions == NULL,
431 ("multicast options set on a divert socket"));
433 * XXXCSJP: It is unclear to me whether or not it makes
434 * sense for divert sockets to have options. However,
435 * for now we will duplicate them with the INP locks
436 * held so we can use them in ip_output() without
437 * requring a reference to the pcb.
439 if (inp->inp_options != NULL) {
440 options = m_dup(inp->inp_options, M_NOWAIT);
441 if (options == NULL) {
451 error = ip_output(m, options, NULL,
452 ((so->so_options & SO_DONTROUTE) ? IP_ROUTETOIF : 0)
453 | IP_ALLOWBROADCAST | IP_RAWOUTPUT, NULL, NULL);
456 case IPV6_VERSION >> 4:
457 error = ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
464 dt->info |= IPFW_IS_DIVERT | IPFW_INFO_IN;
465 if (m->m_pkthdr.rcvif == NULL) {
467 * No luck with the name, check by IP address.
468 * Clear the port and the ifname to make sure
469 * there are no distractions for ifa_ifwithaddr.
473 bzero(sin->sin_zero, sizeof(sin->sin_zero));
475 ifa = ifa_ifwithaddr((struct sockaddr *) sin);
477 error = EADDRNOTAVAIL;
480 m->m_pkthdr.rcvif = ifa->ifa_ifp;
484 mac_socket_create_mbuf(so, m);
486 /* Send packet to input processing via netisr */
489 netisr_queue_src(NETISR_IP, (uintptr_t)so, m);
492 case IPV6_VERSION >> 4:
493 netisr_queue_src(NETISR_IPV6, (uintptr_t)so, m);
510 div_attach(struct socket *so, int proto, struct thread *td)
516 KASSERT(inp == NULL, ("div_attach: inp != NULL"));
518 error = priv_check(td, PRIV_NETINET_DIVERT);
522 error = soreserve(so, div_sendspace, div_recvspace);
525 INP_INFO_WLOCK(&V_divcbinfo);
526 error = in_pcballoc(so, &V_divcbinfo);
528 INP_INFO_WUNLOCK(&V_divcbinfo);
531 inp = (struct inpcb *)so->so_pcb;
532 INP_INFO_WUNLOCK(&V_divcbinfo);
533 inp->inp_ip_p = proto;
534 inp->inp_vflag |= INP_IPV4;
535 inp->inp_flags |= INP_HDRINCL;
541 div_detach(struct socket *so)
546 KASSERT(inp != NULL, ("div_detach: inp == NULL"));
547 INP_INFO_WLOCK(&V_divcbinfo);
551 INP_INFO_WUNLOCK(&V_divcbinfo);
555 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
561 KASSERT(inp != NULL, ("div_bind: inp == NULL"));
562 /* in_pcbbind assumes that nam is a sockaddr_in
563 * and in_pcbbind requires a valid address. Since divert
564 * sockets don't we need to make sure the address is
565 * filled in properly.
566 * XXX -- divert should not be abusing in_pcbind
567 * and should probably have its own family.
569 if (nam->sa_family != AF_INET)
571 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
572 INP_INFO_WLOCK(&V_divcbinfo);
574 INP_HASH_WLOCK(&V_divcbinfo);
575 error = in_pcbbind(inp, nam, td->td_ucred);
576 INP_HASH_WUNLOCK(&V_divcbinfo);
578 INP_INFO_WUNLOCK(&V_divcbinfo);
583 div_shutdown(struct socket *so)
588 KASSERT(inp != NULL, ("div_shutdown: inp == NULL"));
596 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
597 struct mbuf *control, struct thread *td)
600 /* Packet must have a header (but that's about it) */
601 if (m->m_len < sizeof (struct ip) &&
602 (m = m_pullup(m, sizeof (struct ip))) == 0) {
603 KMOD_IPSTAT_INC(ips_toosmall);
609 return div_output(so, m, (struct sockaddr_in *)nam, control);
613 div_ctlinput(int cmd, struct sockaddr *sa, void *vip)
615 struct in_addr faddr;
617 faddr = ((struct sockaddr_in *)sa)->sin_addr;
618 if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
620 if (PRC_IS_REDIRECT(cmd))
625 div_pcblist(SYSCTL_HANDLER_ARGS)
628 struct inpcb *inp, **inp_list;
633 * The process of preparing the TCB list is too time-consuming and
634 * resource-intensive to repeat twice on every request.
636 if (req->oldptr == 0) {
637 n = V_divcbinfo.ipi_count;
638 n += imax(n / 8, 10);
639 req->oldidx = 2 * (sizeof xig) + n * sizeof(struct xinpcb);
643 if (req->newptr != 0)
647 * OK, now we're committed to doing something.
649 INP_INFO_RLOCK(&V_divcbinfo);
650 gencnt = V_divcbinfo.ipi_gencnt;
651 n = V_divcbinfo.ipi_count;
652 INP_INFO_RUNLOCK(&V_divcbinfo);
654 error = sysctl_wire_old_buffer(req,
655 2 * sizeof(xig) + n*sizeof(struct xinpcb));
659 xig.xig_len = sizeof xig;
661 xig.xig_gen = gencnt;
662 xig.xig_sogen = so_gencnt;
663 error = SYSCTL_OUT(req, &xig, sizeof xig);
667 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
671 INP_INFO_RLOCK(&V_divcbinfo);
672 for (inp = LIST_FIRST(V_divcbinfo.ipi_listhead), i = 0; inp && i < n;
673 inp = LIST_NEXT(inp, inp_list)) {
675 if (inp->inp_gencnt <= gencnt &&
676 cr_canseeinpcb(req->td->td_ucred, inp) == 0) {
682 INP_INFO_RUNLOCK(&V_divcbinfo);
686 for (i = 0; i < n; i++) {
689 if (inp->inp_gencnt <= gencnt) {
691 bzero(&xi, sizeof(xi));
692 xi.xi_len = sizeof xi;
693 /* XXX should avoid extra copy */
694 bcopy(inp, &xi.xi_inp, sizeof *inp);
696 sotoxsocket(inp->inp_socket, &xi.xi_socket);
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,
758 .pr_destroy = div_destroy,
760 .pr_usrreqs = &div_usrreqs
764 div_modevent(module_t mod, int type, void *unused)
774 * Protocol will be initialized by pf_proto_register().
775 * We don't have to register ip_protox because we are not
776 * a true IP protocol that goes over the wire.
778 err = pf_proto_register(PF_INET, &div_protosw);
781 ip_divert_ptr = divert_packet;
782 ip_divert_event_tag = EVENTHANDLER_REGISTER(maxsockets_change,
783 div_zone_change, NULL, EVENTHANDLER_PRI_ANY);
787 * IPDIVERT may normally not be unloaded because of the
788 * potential race conditions. Tell kldunload we can't be
789 * unloaded unless the unload is forced.
801 * Module ipdivert can only be unloaded if no sockets are
802 * connected. Maybe this can be changed later to forcefully
803 * disconnect any open sockets.
805 * XXXRW: Note that there is a slight race here, as a new
806 * socket open request could be spinning on the lock and then
807 * we destroy the lock.
809 INP_INFO_WLOCK(&V_divcbinfo);
810 n = V_divcbinfo.ipi_count;
813 INP_INFO_WUNLOCK(&V_divcbinfo);
816 ip_divert_ptr = NULL;
817 err = pf_proto_unregister(PF_INET, IPPROTO_DIVERT, SOCK_RAW);
818 INP_INFO_WUNLOCK(&V_divcbinfo);
820 EVENTHANDLER_DEREGISTER(maxsockets_change, ip_divert_event_tag);
830 static moduledata_t ipdivertmod = {
836 DECLARE_MODULE(ipdivert, ipdivertmod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
837 MODULE_DEPEND(ipdivert, ipfw, 2, 2, 2);
838 MODULE_VERSION(ipdivert, 1);