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33 * $FreeBSD: src/sys/netinet/ip_divert.c,v 1.42.2.6 2003/01/23 21:06:45 sam Exp $
34 * $DragonFly: src/sys/netinet/ip_divert.c,v 1.40 2008/10/21 13:51:01 sephe Exp $
41 #include "opt_ipdivert.h"
42 #include "opt_ipsec.h"
45 #error "IPDIVERT requires INET."
48 #include <sys/param.h>
49 #include <sys/kernel.h>
50 #include <sys/malloc.h>
52 #include <sys/socket.h>
53 #include <sys/protosw.h>
54 #include <sys/socketvar.h>
55 #include <sys/socketvar2.h>
56 #include <sys/sysctl.h>
57 #include <sys/systm.h>
60 #include <sys/in_cksum.h>
63 #include <sys/msgport.h>
67 #include <net/route.h>
70 #include <net/netmsg2.h>
72 #include <sys/thread2.h>
73 #include <sys/mplock2.h>
75 #include <netinet/in.h>
76 #include <netinet/in_systm.h>
77 #include <netinet/ip.h>
78 #include <netinet/in_pcb.h>
79 #include <netinet/in_var.h>
80 #include <netinet/ip_var.h>
81 #include <netinet/ip_divert.h>
88 * Allocate enough space to hold a full IP packet
90 #define DIVSNDQ (65536 + 100)
91 #define DIVRCVQ (65536 + 100)
93 #define DIV_IS_OUTPUT(sin) ((sin) == NULL || (sin)->sin_addr.s_addr == 0)
95 #define DIV_OUTPUT 0x10000
96 #define DIV_INPUT 0x20000
99 * Divert sockets work in conjunction with ipfw, see the divert(4)
100 * manpage for features.
101 * Internally, packets selected by ipfw in ip_input() or ip_output(),
102 * and never diverted before, are passed to the input queue of the
103 * divert socket with a given 'divert_port' number (as specified in
104 * the matching ipfw rule), and they are tagged with a 16 bit cookie
105 * (representing the rule number of the matching ipfw rule), which
106 * is passed to process reading from the socket.
108 * Packets written to the divert socket are again tagged with a cookie
109 * (usually the same as above) and a destination address.
110 * If the destination address is INADDR_ANY then the packet is
111 * treated as outgoing and sent to ip_output(), otherwise it is
112 * treated as incoming and sent to ip_input().
113 * In both cases, the packet is tagged with the cookie.
115 * On reinjection, processing in ip_input() and ip_output()
116 * will be exactly the same as for the original packet, except that
117 * ipfw processing will start at the rule number after the one
118 * written in the cookie (so, tagging a packet with a cookie of 0
119 * will cause it to be effectively considered as a standard packet).
122 /* Internal variables */
123 static struct inpcbinfo divcbinfo;
125 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */
126 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */
128 static struct mbuf *ip_divert(struct mbuf *, int, int);
130 static struct lwkt_token div_token = LWKT_TOKEN_MP_INITIALIZER(div_token);
133 * Initialize divert connection block queue.
138 in_pcbinfo_init(&divcbinfo);
140 * XXX We don't use the hash list for divert IP, but it's easier
141 * to allocate a one entry hash list than it is to check all
142 * over the place for hashbase == NULL.
144 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask);
145 divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask);
146 divcbinfo.wildcardhashbase = hashinit(1, M_PCB,
147 &divcbinfo.wildcardhashmask);
148 divcbinfo.ipi_size = sizeof(struct inpcb);
149 ip_divert_p = ip_divert;
153 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets
154 * with that protocol number to enter the system from the outside.
157 div_input(struct mbuf **mp, int *offp, int proto)
159 struct mbuf *m = *mp;
161 ipstat.ips_noproto++;
163 return(IPPROTO_DONE);
167 div_soport(struct socket *so, struct sockaddr *nam, struct mbuf **mptr)
169 struct sockaddr_in *sin;
173 sin = (struct sockaddr_in *)nam;
177 m->m_pkthdr.rcvif = NULL;
178 dir = DIV_IS_OUTPUT(sin) ? IP_MPORT_OUT : IP_MPORT_IN;
184 * Try locating the interface, if we originally had one.
185 * This is done even for outgoing packets, since for a
186 * forwarded packet, there must be an interface attached.
188 * Find receive interface with the given name, stuffed
189 * (if it exists) in the sin_zero[] field.
190 * The name is user supplied data so don't trust its size
191 * or that it is zero terminated.
193 for (i = 0; sin->sin_zero[i] && i < sizeof(sin->sin_zero); i++)
195 if (i > 0 && i < sizeof(sin->sin_zero))
196 m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
199 if (dir == IP_MPORT_IN && m->m_pkthdr.rcvif == NULL) {
201 * No luck with the name, check by IP address.
202 * Clear the port and the ifname to make sure
203 * there are no distractions for ifa_ifwithaddr.
205 * Be careful not to trash sin->sin_port; it will
206 * be used later in div_output().
211 bzero(sin->sin_zero, sizeof(sin->sin_zero));
212 sin_port = sin->sin_port; /* save */
214 ifa = ifa_ifwithaddr((struct sockaddr *)sin);
220 sin->sin_port = sin_port; /* restore */
221 m->m_pkthdr.rcvif = ifa->ifa_ifp;
225 * Recalculate the protocol thread.
227 ip_cpufn(mptr, 0, dir);
230 KKASSERT(m->m_flags & M_HASH);
231 return(cpu_portfn(m->m_pkthdr.hash));
237 * Divert a packet by passing it up to the divert socket at port 'port'.
239 * Setup generic address and protocol structures for div_input routine,
240 * then pass them along with mbuf chain.
243 div_packet(struct mbuf *m, int incoming, int port)
245 struct sockaddr_in divsrc = { sizeof divsrc, AF_INET };
249 struct divert_info *divinfo;
252 /* Locate the divert info */
253 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
254 divinfo = m_tag_data(mtag);
255 divsrc.sin_port = divinfo->skipto;
258 * Record receive interface address, if any.
259 * But only for incoming packets.
261 divsrc.sin_addr.s_addr = 0;
263 struct ifaddr_container *ifac;
265 /* Find IP address for receive interface */
266 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid],
268 struct ifaddr *ifa = ifac->ifa;
270 if (ifa->ifa_addr == NULL)
272 if (ifa->ifa_addr->sa_family != AF_INET)
275 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
280 * Record the incoming interface name whenever we have one.
282 if (m->m_pkthdr.rcvif) {
284 * Hide the actual interface name in there in the
285 * sin_zero array. XXX This needs to be moved to a
286 * different sockaddr type for divert, e.g.
287 * sockaddr_div with multiple fields like
288 * sockaddr_dl. Presently we have only 7 bytes
289 * but that will do for now as most interfaces
290 * are 4 or less + 2 or less bytes for unit.
291 * There is probably a faster way of doing this,
292 * possibly taking it from the sockaddr_dl on the iface.
293 * This solves the problem of a P2P link and a LAN interface
294 * having the same address, which can result in the wrong
295 * interface being assigned to the packet when fed back
296 * into the divert socket. Theoretically if the daemon saves
297 * and re-uses the sockaddr_in as suggested in the man pages,
298 * this iface name will come along for the ride.
299 * (see div_output for the other half of this.)
301 ksnprintf(divsrc.sin_zero, sizeof divsrc.sin_zero,
302 m->m_pkthdr.rcvif->if_xname);
305 /* Put packet on socket queue, if any */
307 nport = htons((u_int16_t)port);
311 * Following loop to locate the inpcb is MPSAFE since the inpcb
312 * insertion/removal happens on the same CPU (CPU0), however,
313 * saving/testing the socket pointer is not MPSAFE. So we still
314 * need to hold BGL here.
316 lwkt_gettoken(&div_token);
317 LIST_FOREACH(inp, &divcbinfo.pcblisthead, inp_list) {
318 if (inp->inp_flags & INP_PLACEMARKER)
320 if (inp->inp_lport == nport)
321 sa = inp->inp_socket;
324 lwkt_gettoken(&sa->so_rcv.ssb_token);
325 if (ssb_appendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m, NULL) == 0)
329 lwkt_reltoken(&sa->so_rcv.ssb_token);
332 ipstat.ips_noproto++;
333 ipstat.ips_delivered--;
335 lwkt_reltoken(&div_token);
341 div_packet_handler(netmsg_t msg)
344 int port, incoming = 0;
346 m = msg->packet.nm_packet;
348 port = msg->lmsg.u.ms_result32 & 0xffff;
349 if (msg->lmsg.u.ms_result32 & DIV_INPUT)
351 div_packet(m, incoming, port);
352 /* no reply, msg embedded in mbuf */
358 divert_packet(struct mbuf *m, int incoming)
361 struct divert_info *divinfo;
367 if (m->m_len < sizeof(struct ip) &&
368 (m = m_pullup(m, sizeof(struct ip))) == NULL)
371 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
372 KASSERT(mtag != NULL, ("%s no divert tag!", __func__));
373 divinfo = m_tag_data(mtag);
375 port = divinfo->port;
376 KASSERT(port != 0, ("%s: port=0", __func__));
380 struct netmsg_packet *nmp;
382 nmp = &m->m_hdr.mh_netmsg;
383 netmsg_init(&nmp->base, NULL, &netisr_apanic_rport,
384 0, div_packet_handler);
387 nmp->base.lmsg.u.ms_result32 = port; /* port is 16bits */
389 nmp->base.lmsg.u.ms_result32 |= DIV_INPUT;
391 nmp->base.lmsg.u.ms_result32 |= DIV_OUTPUT;
393 lwkt_sendmsg(cpu_portfn(0), &nmp->base.lmsg);
396 div_packet(m, incoming, port);
400 * Deliver packet back into the IP processing machinery.
402 * If no address specified, or address is 0.0.0.0, send to ip_output();
403 * otherwise, send to ip_input() and mark as having been received on
404 * the interface with that address.
407 div_output(struct socket *so, struct mbuf *m,
408 struct sockaddr_in *sin, struct mbuf *control)
412 struct divert_info *divinfo;
415 m_freem(control); /* XXX */
418 * Prepare the tag for divert info. Note that a packet
419 * with a 0 tag in mh_data is effectively untagged,
420 * so we could optimize that case.
422 mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT, sizeof(*divinfo), MB_DONTWAIT);
427 m_tag_prepend(m, mtag);
429 /* Loopback avoidance and state recovery */
430 divinfo = m_tag_data(mtag);
432 divinfo->skipto = sin->sin_port;
436 /* Reinject packet into the system as incoming or outgoing */
437 if (DIV_IS_OUTPUT(sin)) {
438 struct ip *const ip = mtod(m, struct ip *);
440 /* Don't allow packet length sizes that will crash */
441 if ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len) {
446 /* Convert fields to host order for ip_output() */
447 ip->ip_len = ntohs(ip->ip_len);
448 ip->ip_off = ntohs(ip->ip_off);
450 /* Send packet to output processing */
451 ipstat.ips_rawout++; /* XXX */
452 error = ip_output(m, NULL, NULL,
453 (so->so_options & SO_DONTROUTE) |
454 IP_ALLOWBROADCAST | IP_RAWOUTPUT,
467 div_attach(netmsg_t msg)
469 struct socket *so = msg->attach.base.nm_so;
470 int proto = msg->attach.nm_proto;
471 struct pru_attach_info *ai = msg->attach.nm_ai;
478 error = priv_check_cred(ai->p_ucred, PRIV_ROOT, NULL_CRED_OKAY);
482 error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit);
485 lwkt_gettoken(&div_token);
486 so->so_port = cpu0_soport(so, NULL, NULL);
487 error = in_pcballoc(so, &divcbinfo);
489 lwkt_reltoken(&div_token);
492 inp = (struct inpcb *)so->so_pcb;
493 inp->inp_ip_p = proto;
494 inp->inp_vflag |= INP_IPV4;
495 inp->inp_flags |= INP_HDRINCL;
497 * The socket is always "connected" because
498 * we always know "where" to send the packet.
500 sosetstate(so, SS_ISCONNECTED);
501 lwkt_reltoken(&div_token);
504 lwkt_replymsg(&msg->attach.base.lmsg, error);
508 div_detach(netmsg_t msg)
510 struct socket *so = msg->detach.base.nm_so;
517 lwkt_replymsg(&msg->detach.base.lmsg, 0);
521 * NOTE: (so) is referenced from soabort*() and netmsg_pru_abort()
522 * will sofree() it when we return.
525 div_abort(netmsg_t msg)
527 struct socket *so = msg->abort.base.nm_so;
529 soisdisconnected(so);
531 /* msg invalid now */
535 div_disconnect(netmsg_t msg)
537 struct socket *so = msg->disconnect.base.nm_so;
540 if (so->so_state & SS_ISCONNECTED) {
543 /* msg invalid now */
548 lwkt_replymsg(&msg->disconnect.base.lmsg, error);
552 div_bind(netmsg_t msg)
554 struct socket *so = msg->bind.base.nm_so;
555 struct sockaddr *nam = msg->bind.nm_nam;
559 * in_pcbbind assumes that nam is a sockaddr_in
560 * and in_pcbbind requires a valid address. Since divert
561 * sockets don't we need to make sure the address is
562 * filled in properly.
563 * XXX -- divert should not be abusing in_pcbind
564 * and should probably have its own family.
566 if (nam->sa_family != AF_INET) {
567 error = EAFNOSUPPORT;
569 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
570 error = in_pcbbind(so->so_pcb, nam, msg->bind.nm_td);
572 lwkt_replymsg(&msg->bind.base.lmsg, error);
576 div_shutdown(netmsg_t msg)
578 struct socket *so = msg->shutdown.base.nm_so;
582 lwkt_replymsg(&msg->shutdown.base.lmsg, 0);
586 div_send(netmsg_t msg)
588 struct socket *so = msg->send.base.nm_so;
589 struct mbuf *m = msg->send.nm_m;
590 struct sockaddr *nam = msg->send.nm_addr;
591 struct mbuf *control = msg->send.nm_control;
594 /* Length check already done in ip_cpufn() */
595 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf"));
598 error = div_output(so, m, (struct sockaddr_in *)nam, control);
599 lwkt_replymsg(&msg->send.base.lmsg, error);
602 SYSCTL_DECL(_net_inet_divert);
603 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 0,
604 in_pcblist_global, "S,xinpcb", "List of active divert sockets");
606 struct pr_usrreqs div_usrreqs = {
607 .pru_abort = div_abort,
608 .pru_accept = pr_generic_notsupp,
609 .pru_attach = div_attach,
610 .pru_bind = div_bind,
611 .pru_connect = pr_generic_notsupp,
612 .pru_connect2 = pr_generic_notsupp,
613 .pru_control = in_control_dispatch,
614 .pru_detach = div_detach,
615 .pru_disconnect = div_disconnect,
616 .pru_listen = pr_generic_notsupp,
617 .pru_peeraddr = in_setpeeraddr_dispatch,
618 .pru_rcvd = pr_generic_notsupp,
619 .pru_rcvoob = pr_generic_notsupp,
620 .pru_send = div_send,
621 .pru_sense = pru_sense_null,
622 .pru_shutdown = div_shutdown,
623 .pru_sockaddr = in_setsockaddr_dispatch,
624 .pru_sosend = sosend,
625 .pru_soreceive = soreceive
629 ip_divert_out(struct mbuf *m, int tee)
631 struct mbuf *clone = NULL;
632 struct ip *ip = mtod(m, struct ip *);
634 /* Clone packet if we're doing a 'tee' */
636 clone = m_dup(m, MB_DONTWAIT);
640 * delayed checksums are not currently compatible
641 * with divert sockets.
643 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
645 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
648 /* Restore packet header fields to original values */
649 ip->ip_len = htons(ip->ip_len);
650 ip->ip_off = htons(ip->ip_off);
652 /* Deliver packet to divert input routine */
655 /* If 'tee', continue with original packet */
660 ip_divert_in(struct mbuf *m, int tee)
662 struct mbuf *clone = NULL;
663 struct ip *ip = mtod(m, struct ip *);
666 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
667 const struct divert_info *divinfo;
672 * Only trust divert info in the fragment
675 frag_off = ip->ip_off << 3;
677 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
678 m_tag_delete(m, mtag);
682 * Attempt reassembly; if it succeeds, proceed.
683 * ip_reass() will return a different mbuf.
688 ip = mtod(m, struct ip *);
690 /* Caller need to redispatch the packet, if it is for us */
691 m->m_pkthdr.fw_flags |= FW_MBUF_REDISPATCH;
694 * Get the header length of the reassembled
697 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
700 * Restore original checksum before diverting
704 ip->ip_len = htons(ip->ip_len);
705 ip->ip_off = htons(ip->ip_off);
707 if (hlen == sizeof(struct ip))
708 ip->ip_sum = in_cksum_hdr(ip);
710 ip->ip_sum = in_cksum(m, hlen);
711 ip->ip_off = ntohs(ip->ip_off);
712 ip->ip_len = ntohs(ip->ip_len);
715 * Only use the saved divert info
717 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
719 /* Wrongly configured ipfw */
720 kprintf("ip_input no divert info\n");
724 divinfo = m_tag_data(mtag);
729 * Divert or tee packet to the divert protocol if
733 /* Clone packet if we're doing a 'tee' */
735 clone = m_dup(m, MB_DONTWAIT);
738 * Restore packet header fields to original
741 ip->ip_len = htons(ip->ip_len);
742 ip->ip_off = htons(ip->ip_off);
744 /* Deliver packet to divert input routine */
747 /* Catch invalid reference */
751 ipstat.ips_delivered++;
753 /* If 'tee', continue with original packet */
756 * Complete processing of the packet.
757 * XXX Better safe than sorry, remove the DIVERT tag.
759 mtag = m_tag_find(clone, PACKET_TAG_IPFW_DIVERT, NULL);
760 KKASSERT(mtag != NULL);
761 m_tag_delete(clone, mtag);
767 ip_divert(struct mbuf *m, int tee, int incoming)
772 ret = ip_divert_in(m, tee);
774 ret = ip_divert_out(m, tee);