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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/sysctl.h>
56 #include <sys/systm.h>
59 #include <sys/in_cksum.h>
62 #include <sys/msgport.h>
65 #include <vm/vm_zone.h>
68 #include <net/route.h>
71 #include <net/netmsg2.h>
73 #include <sys/thread2.h>
74 #include <sys/mplock2.h>
76 #include <netinet/in.h>
77 #include <netinet/in_systm.h>
78 #include <netinet/ip.h>
79 #include <netinet/in_pcb.h>
80 #include <netinet/in_var.h>
81 #include <netinet/ip_var.h>
82 #include <netinet/ip_divert.h>
89 * Allocate enough space to hold a full IP packet
91 #define DIVSNDQ (65536 + 100)
92 #define DIVRCVQ (65536 + 100)
94 #define DIV_IS_OUTPUT(sin) ((sin) == NULL || (sin)->sin_addr.s_addr == 0)
96 #define DIV_OUTPUT 0x10000
97 #define DIV_INPUT 0x20000
100 * Divert sockets work in conjunction with ipfw, see the divert(4)
101 * manpage for features.
102 * Internally, packets selected by ipfw in ip_input() or ip_output(),
103 * and never diverted before, are passed to the input queue of the
104 * divert socket with a given 'divert_port' number (as specified in
105 * the matching ipfw rule), and they are tagged with a 16 bit cookie
106 * (representing the rule number of the matching ipfw rule), which
107 * is passed to process reading from the socket.
109 * Packets written to the divert socket are again tagged with a cookie
110 * (usually the same as above) and a destination address.
111 * If the destination address is INADDR_ANY then the packet is
112 * treated as outgoing and sent to ip_output(), otherwise it is
113 * treated as incoming and sent to ip_input().
114 * In both cases, the packet is tagged with the cookie.
116 * On reinjection, processing in ip_input() and ip_output()
117 * will be exactly the same as for the original packet, except that
118 * ipfw processing will start at the rule number after the one
119 * written in the cookie (so, tagging a packet with a cookie of 0
120 * will cause it to be effectively considered as a standard packet).
123 /* Internal variables */
124 static struct inpcbinfo divcbinfo;
126 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */
127 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */
129 static struct mbuf *ip_divert(struct mbuf *, int, int);
132 * Initialize divert connection block queue.
137 in_pcbinfo_init(&divcbinfo);
139 * XXX We don't use the hash list for divert IP, but it's easier
140 * to allocate a one entry hash list than it is to check all
141 * over the place for hashbase == NULL.
143 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask);
144 divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask);
145 divcbinfo.wildcardhashbase = hashinit(1, M_PCB,
146 &divcbinfo.wildcardhashmask);
147 divcbinfo.ipi_zone = zinit("divcb", sizeof(struct inpcb),
148 maxsockets, ZONE_INTERRUPT, 0);
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 *m, ...)
159 ipstat.ips_noproto++;
164 div_soport(struct socket *so, struct sockaddr *nam, struct mbuf **mptr)
166 struct sockaddr_in *sin;
170 sin = (struct sockaddr_in *)nam;
174 m->m_pkthdr.rcvif = NULL;
175 dir = DIV_IS_OUTPUT(sin) ? IP_MPORT_OUT : IP_MPORT_IN;
181 * Try locating the interface, if we originally had one.
182 * This is done even for outgoing packets, since for a
183 * forwarded packet, there must be an interface attached.
185 * Find receive interface with the given name, stuffed
186 * (if it exists) in the sin_zero[] field.
187 * The name is user supplied data so don't trust its size
188 * or that it is zero terminated.
190 for (i = 0; sin->sin_zero[i] && i < sizeof(sin->sin_zero); i++)
192 if (i > 0 && i < sizeof(sin->sin_zero))
193 m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
196 if (dir == IP_MPORT_IN && m->m_pkthdr.rcvif == NULL) {
198 * No luck with the name, check by IP address.
199 * Clear the port and the ifname to make sure
200 * there are no distractions for ifa_ifwithaddr.
202 * Be careful not to trash sin->sin_port; it will
203 * be used later in div_output().
208 bzero(sin->sin_zero, sizeof(sin->sin_zero));
209 sin_port = sin->sin_port; /* save */
211 ifa = ifa_ifwithaddr((struct sockaddr *)sin);
217 sin->sin_port = sin_port; /* restore */
218 m->m_pkthdr.rcvif = ifa->ifa_ifp;
221 return ip_mport(mptr, dir);
225 * Divert a packet by passing it up to the divert socket at port 'port'.
227 * Setup generic address and protocol structures for div_input routine,
228 * then pass them along with mbuf chain.
231 div_packet(struct mbuf *m, int incoming, int port)
233 struct sockaddr_in divsrc = { sizeof divsrc, AF_INET };
237 struct divert_info *divinfo;
240 /* Locate the divert info */
241 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
242 divinfo = m_tag_data(mtag);
243 divsrc.sin_port = divinfo->skipto;
246 * Record receive interface address, if any.
247 * But only for incoming packets.
249 divsrc.sin_addr.s_addr = 0;
251 struct ifaddr_container *ifac;
253 /* Find IP address for receive interface */
254 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid],
256 struct ifaddr *ifa = ifac->ifa;
258 if (ifa->ifa_addr == NULL)
260 if (ifa->ifa_addr->sa_family != AF_INET)
263 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
268 * Record the incoming interface name whenever we have one.
270 if (m->m_pkthdr.rcvif) {
272 * Hide the actual interface name in there in the
273 * sin_zero array. XXX This needs to be moved to a
274 * different sockaddr type for divert, e.g.
275 * sockaddr_div with multiple fields like
276 * sockaddr_dl. Presently we have only 7 bytes
277 * but that will do for now as most interfaces
278 * are 4 or less + 2 or less bytes for unit.
279 * There is probably a faster way of doing this,
280 * possibly taking it from the sockaddr_dl on the iface.
281 * This solves the problem of a P2P link and a LAN interface
282 * having the same address, which can result in the wrong
283 * interface being assigned to the packet when fed back
284 * into the divert socket. Theoretically if the daemon saves
285 * and re-uses the sockaddr_in as suggested in the man pages,
286 * this iface name will come along for the ride.
287 * (see div_output for the other half of this.)
289 ksnprintf(divsrc.sin_zero, sizeof divsrc.sin_zero,
290 m->m_pkthdr.rcvif->if_xname);
293 /* Put packet on socket queue, if any */
295 nport = htons((u_int16_t)port);
299 * Following loop to locate the inpcb is MPSAFE since the inpcb
300 * insertion/removal happens on the same CPU (CPU0), however,
301 * saving/testing the socket pointer is not MPSAFE. So we still
302 * need to hold BGL here.
305 LIST_FOREACH(inp, &divcbinfo.pcblisthead, inp_list) {
306 if (inp->inp_flags & INP_PLACEMARKER)
308 if (inp->inp_lport == nport)
309 sa = inp->inp_socket;
312 if (ssb_appendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m,
321 ipstat.ips_noproto++;
322 ipstat.ips_delivered--;
328 div_packet_handler(struct netmsg *nmsg)
330 struct netmsg_packet *nmp;
331 struct lwkt_msg *msg;
333 int port, incoming = 0;
335 nmp = (struct netmsg_packet *)nmsg;
338 msg = &nmsg->nm_lmsg;
339 port = msg->u.ms_result32 & 0xffff;
340 if (msg->u.ms_result32 & DIV_INPUT)
343 div_packet(m, incoming, port);
348 divert_packet(struct mbuf *m, int incoming)
351 struct divert_info *divinfo;
357 if (m->m_len < sizeof(struct ip) &&
358 (m = m_pullup(m, sizeof(struct ip))) == NULL)
361 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
362 KASSERT(mtag != NULL, ("%s no divert tag!", __func__));
363 divinfo = m_tag_data(mtag);
365 port = divinfo->port;
366 KASSERT(port != 0, ("%s: port=0", __func__));
370 struct netmsg_packet *nmp;
371 struct lwkt_msg *msg;
373 nmp = &m->m_hdr.mh_netmsg;
374 netmsg_init(&nmp->nm_netmsg, NULL, &netisr_apanic_rport,
375 MSGF_MPSAFE, div_packet_handler);
378 msg = &nmp->nm_netmsg.nm_lmsg;
379 msg->u.ms_result32 = port; /* port is 16bits */
381 msg->u.ms_result32 |= DIV_INPUT;
383 msg->u.ms_result32 |= DIV_OUTPUT;
385 lwkt_sendmsg(cpu_portfn(0), &nmp->nm_netmsg.nm_lmsg);
388 div_packet(m, incoming, port);
392 * Deliver packet back into the IP processing machinery.
394 * If no address specified, or address is 0.0.0.0, send to ip_output();
395 * otherwise, send to ip_input() and mark as having been received on
396 * the interface with that address.
399 div_output(struct socket *so, struct mbuf *m,
400 struct sockaddr_in *sin, struct mbuf *control)
404 struct divert_info *divinfo;
407 m_freem(control); /* XXX */
410 * Prepare the tag for divert info. Note that a packet
411 * with a 0 tag in mh_data is effectively untagged,
412 * so we could optimize that case.
414 mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT, sizeof(*divinfo), MB_DONTWAIT);
419 m_tag_prepend(m, mtag);
421 /* Loopback avoidance and state recovery */
422 divinfo = m_tag_data(mtag);
424 divinfo->skipto = sin->sin_port;
428 /* Reinject packet into the system as incoming or outgoing */
429 if (DIV_IS_OUTPUT(sin)) {
430 struct ip *const ip = mtod(m, struct ip *);
432 /* Don't allow packet length sizes that will crash */
433 if ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len) {
438 /* Convert fields to host order for ip_output() */
439 ip->ip_len = ntohs(ip->ip_len);
440 ip->ip_off = ntohs(ip->ip_off);
442 /* Send packet to output processing */
443 ipstat.ips_rawout++; /* XXX */
444 error = ip_output(m, NULL, NULL,
445 (so->so_options & SO_DONTROUTE) |
446 IP_ALLOWBROADCAST | IP_RAWOUTPUT,
459 div_attach(struct socket *so, int proto, struct pru_attach_info *ai)
467 if ((error = priv_check_cred(ai->p_ucred, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
470 error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit);
473 error = in_pcballoc(so, &divcbinfo);
476 inp = (struct inpcb *)so->so_pcb;
477 inp->inp_ip_p = proto;
478 inp->inp_vflag |= INP_IPV4;
479 inp->inp_flags |= INP_HDRINCL;
481 * The socket is always "connected" because
482 * we always know "where" to send the packet.
484 so->so_port = cpu0_soport(so, NULL, NULL);
485 so->so_state |= SS_ISCONNECTED;
490 div_detach(struct socket *so)
502 div_abort(struct socket *so)
504 soisdisconnected(so);
505 return div_detach(so);
509 div_disconnect(struct socket *so)
511 if (!(so->so_state & SS_ISCONNECTED))
513 return div_abort(so);
517 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
522 * in_pcbbind assumes that nam is a sockaddr_in
523 * and in_pcbbind requires a valid address. Since divert
524 * sockets don't we need to make sure the address is
525 * filled in properly.
526 * XXX -- divert should not be abusing in_pcbind
527 * and should probably have its own family.
529 if (nam->sa_family != AF_INET) {
530 error = EAFNOSUPPORT;
532 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
533 error = in_pcbbind(so->so_pcb, nam, td);
539 div_shutdown(struct socket *so)
546 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
547 struct mbuf *control, struct thread *td)
549 /* Length check already done in ip_mport() */
550 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf"));
553 return div_output(so, m, (struct sockaddr_in *)nam, control);
556 SYSCTL_DECL(_net_inet_divert);
557 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 0,
558 in_pcblist_global, "S,xinpcb", "List of active divert sockets");
560 struct pr_usrreqs div_usrreqs = {
561 .pru_abort = div_abort,
562 .pru_accept = pru_accept_notsupp,
563 .pru_attach = div_attach,
564 .pru_bind = div_bind,
565 .pru_connect = pru_connect_notsupp,
566 .pru_connect2 = pru_connect2_notsupp,
567 .pru_control = in_control,
568 .pru_detach = div_detach,
569 .pru_disconnect = div_disconnect,
570 .pru_listen = pru_listen_notsupp,
571 .pru_peeraddr = in_setpeeraddr,
572 .pru_rcvd = pru_rcvd_notsupp,
573 .pru_rcvoob = pru_rcvoob_notsupp,
574 .pru_send = div_send,
575 .pru_sense = pru_sense_null,
576 .pru_shutdown = div_shutdown,
577 .pru_sockaddr = in_setsockaddr,
578 .pru_sosend = sosend,
579 .pru_soreceive = soreceive,
584 ip_divert_out(struct mbuf *m, int tee)
586 struct mbuf *clone = NULL;
587 struct ip *ip = mtod(m, struct ip *);
589 /* Clone packet if we're doing a 'tee' */
591 clone = m_dup(m, MB_DONTWAIT);
595 * delayed checksums are not currently compatible
596 * with divert sockets.
598 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
600 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
603 /* Restore packet header fields to original values */
604 ip->ip_len = htons(ip->ip_len);
605 ip->ip_off = htons(ip->ip_off);
607 /* Deliver packet to divert input routine */
610 /* If 'tee', continue with original packet */
615 ip_divert_in(struct mbuf *m, int tee)
617 struct mbuf *clone = NULL;
618 struct ip *ip = mtod(m, struct ip *);
621 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
622 const struct divert_info *divinfo;
627 * Only trust divert info in the fragment
630 frag_off = ip->ip_off << 3;
632 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
633 m_tag_delete(m, mtag);
637 * Attempt reassembly; if it succeeds, proceed.
638 * ip_reass() will return a different mbuf.
643 ip = mtod(m, struct ip *);
645 /* Caller need to redispatch the packet, if it is for us */
646 m->m_pkthdr.fw_flags |= FW_MBUF_REDISPATCH;
649 * Get the header length of the reassembled
652 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
655 * Restore original checksum before diverting
659 ip->ip_len = htons(ip->ip_len);
660 ip->ip_off = htons(ip->ip_off);
662 if (hlen == sizeof(struct ip))
663 ip->ip_sum = in_cksum_hdr(ip);
665 ip->ip_sum = in_cksum(m, hlen);
666 ip->ip_off = ntohs(ip->ip_off);
667 ip->ip_len = ntohs(ip->ip_len);
670 * Only use the saved divert info
672 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
674 /* Wrongly configured ipfw */
675 kprintf("ip_input no divert info\n");
679 divinfo = m_tag_data(mtag);
684 * Divert or tee packet to the divert protocol if
688 /* Clone packet if we're doing a 'tee' */
690 clone = m_dup(m, MB_DONTWAIT);
693 * Restore packet header fields to original
696 ip->ip_len = htons(ip->ip_len);
697 ip->ip_off = htons(ip->ip_off);
699 /* Deliver packet to divert input routine */
702 /* Catch invalid reference */
706 ipstat.ips_delivered++;
708 /* If 'tee', continue with original packet */
711 * Complete processing of the packet.
712 * XXX Better safe than sorry, remove the DIVERT tag.
714 mtag = m_tag_find(clone, PACKET_TAG_IPFW_DIVERT, NULL);
715 KKASSERT(mtag != NULL);
716 m_tag_delete(clone, mtag);
722 ip_divert(struct mbuf *m, int tee, int incoming)
727 ret = ip_divert_in(m, tee);
729 ret = ip_divert_out(m, tee);