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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>
66 #include <net/route.h>
69 #include <net/netmsg2.h>
71 #include <sys/thread2.h>
72 #include <sys/mplock2.h>
74 #include <netinet/in.h>
75 #include <netinet/in_systm.h>
76 #include <netinet/ip.h>
77 #include <netinet/in_pcb.h>
78 #include <netinet/in_var.h>
79 #include <netinet/ip_var.h>
80 #include <netinet/ip_divert.h>
87 * Allocate enough space to hold a full IP packet
89 #define DIVSNDQ (65536 + 100)
90 #define DIVRCVQ (65536 + 100)
92 #define DIV_IS_OUTPUT(sin) ((sin) == NULL || (sin)->sin_addr.s_addr == 0)
94 #define DIV_OUTPUT 0x10000
95 #define DIV_INPUT 0x20000
98 * Divert sockets work in conjunction with ipfw, see the divert(4)
99 * manpage for features.
100 * Internally, packets selected by ipfw in ip_input() or ip_output(),
101 * and never diverted before, are passed to the input queue of the
102 * divert socket with a given 'divert_port' number (as specified in
103 * the matching ipfw rule), and they are tagged with a 16 bit cookie
104 * (representing the rule number of the matching ipfw rule), which
105 * is passed to process reading from the socket.
107 * Packets written to the divert socket are again tagged with a cookie
108 * (usually the same as above) and a destination address.
109 * If the destination address is INADDR_ANY then the packet is
110 * treated as outgoing and sent to ip_output(), otherwise it is
111 * treated as incoming and sent to ip_input().
112 * In both cases, the packet is tagged with the cookie.
114 * On reinjection, processing in ip_input() and ip_output()
115 * will be exactly the same as for the original packet, except that
116 * ipfw processing will start at the rule number after the one
117 * written in the cookie (so, tagging a packet with a cookie of 0
118 * will cause it to be effectively considered as a standard packet).
121 /* Internal variables */
122 static struct inpcbinfo divcbinfo;
124 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */
125 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */
127 static struct mbuf *ip_divert(struct mbuf *, int, int);
130 * Initialize divert connection block queue.
135 in_pcbinfo_init(&divcbinfo);
137 * XXX We don't use the hash list for divert IP, but it's easier
138 * to allocate a one entry hash list than it is to check all
139 * over the place for hashbase == NULL.
141 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask);
142 divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask);
143 divcbinfo.wildcardhashbase = hashinit(1, M_PCB,
144 &divcbinfo.wildcardhashmask);
145 divcbinfo.ipi_size = sizeof(struct inpcb);
146 ip_divert_p = ip_divert;
150 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets
151 * with that protocol number to enter the system from the outside.
154 div_input(struct mbuf *m, ...)
156 ipstat.ips_noproto++;
161 div_soport(struct socket *so, struct sockaddr *nam, struct mbuf **mptr)
163 struct sockaddr_in *sin;
167 sin = (struct sockaddr_in *)nam;
171 m->m_pkthdr.rcvif = NULL;
172 dir = DIV_IS_OUTPUT(sin) ? IP_MPORT_OUT : IP_MPORT_IN;
178 * Try locating the interface, if we originally had one.
179 * This is done even for outgoing packets, since for a
180 * forwarded packet, there must be an interface attached.
182 * Find receive interface with the given name, stuffed
183 * (if it exists) in the sin_zero[] field.
184 * The name is user supplied data so don't trust its size
185 * or that it is zero terminated.
187 for (i = 0; sin->sin_zero[i] && i < sizeof(sin->sin_zero); i++)
189 if (i > 0 && i < sizeof(sin->sin_zero))
190 m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
193 if (dir == IP_MPORT_IN && m->m_pkthdr.rcvif == NULL) {
195 * No luck with the name, check by IP address.
196 * Clear the port and the ifname to make sure
197 * there are no distractions for ifa_ifwithaddr.
199 * Be careful not to trash sin->sin_port; it will
200 * be used later in div_output().
205 bzero(sin->sin_zero, sizeof(sin->sin_zero));
206 sin_port = sin->sin_port; /* save */
208 ifa = ifa_ifwithaddr((struct sockaddr *)sin);
214 sin->sin_port = sin_port; /* restore */
215 m->m_pkthdr.rcvif = ifa->ifa_ifp;
218 return ip_mport(mptr, dir);
222 * Divert a packet by passing it up to the divert socket at port 'port'.
224 * Setup generic address and protocol structures for div_input routine,
225 * then pass them along with mbuf chain.
228 div_packet(struct mbuf *m, int incoming, int port)
230 struct sockaddr_in divsrc = { sizeof divsrc, AF_INET };
234 struct divert_info *divinfo;
237 /* Locate the divert info */
238 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
239 divinfo = m_tag_data(mtag);
240 divsrc.sin_port = divinfo->skipto;
243 * Record receive interface address, if any.
244 * But only for incoming packets.
246 divsrc.sin_addr.s_addr = 0;
248 struct ifaddr_container *ifac;
250 /* Find IP address for receive interface */
251 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid],
253 struct ifaddr *ifa = ifac->ifa;
255 if (ifa->ifa_addr == NULL)
257 if (ifa->ifa_addr->sa_family != AF_INET)
260 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
265 * Record the incoming interface name whenever we have one.
267 if (m->m_pkthdr.rcvif) {
269 * Hide the actual interface name in there in the
270 * sin_zero array. XXX This needs to be moved to a
271 * different sockaddr type for divert, e.g.
272 * sockaddr_div with multiple fields like
273 * sockaddr_dl. Presently we have only 7 bytes
274 * but that will do for now as most interfaces
275 * are 4 or less + 2 or less bytes for unit.
276 * There is probably a faster way of doing this,
277 * possibly taking it from the sockaddr_dl on the iface.
278 * This solves the problem of a P2P link and a LAN interface
279 * having the same address, which can result in the wrong
280 * interface being assigned to the packet when fed back
281 * into the divert socket. Theoretically if the daemon saves
282 * and re-uses the sockaddr_in as suggested in the man pages,
283 * this iface name will come along for the ride.
284 * (see div_output for the other half of this.)
286 ksnprintf(divsrc.sin_zero, sizeof divsrc.sin_zero,
287 m->m_pkthdr.rcvif->if_xname);
290 /* Put packet on socket queue, if any */
292 nport = htons((u_int16_t)port);
296 * Following loop to locate the inpcb is MPSAFE since the inpcb
297 * insertion/removal happens on the same CPU (CPU0), however,
298 * saving/testing the socket pointer is not MPSAFE. So we still
299 * need to hold BGL here.
302 LIST_FOREACH(inp, &divcbinfo.pcblisthead, inp_list) {
303 if (inp->inp_flags & INP_PLACEMARKER)
305 if (inp->inp_lport == nport)
306 sa = inp->inp_socket;
309 if (ssb_appendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m,
318 ipstat.ips_noproto++;
319 ipstat.ips_delivered--;
325 div_packet_handler(struct netmsg *nmsg)
327 struct netmsg_packet *nmp;
328 struct lwkt_msg *msg;
330 int port, incoming = 0;
332 nmp = (struct netmsg_packet *)nmsg;
335 msg = &nmsg->nm_lmsg;
336 port = msg->u.ms_result32 & 0xffff;
337 if (msg->u.ms_result32 & DIV_INPUT)
340 div_packet(m, incoming, port);
345 divert_packet(struct mbuf *m, int incoming)
348 struct divert_info *divinfo;
354 if (m->m_len < sizeof(struct ip) &&
355 (m = m_pullup(m, sizeof(struct ip))) == NULL)
358 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
359 KASSERT(mtag != NULL, ("%s no divert tag!", __func__));
360 divinfo = m_tag_data(mtag);
362 port = divinfo->port;
363 KASSERT(port != 0, ("%s: port=0", __func__));
367 struct netmsg_packet *nmp;
368 struct lwkt_msg *msg;
370 nmp = &m->m_hdr.mh_netmsg;
371 netmsg_init(&nmp->nm_netmsg, NULL, &netisr_apanic_rport,
372 MSGF_MPSAFE, div_packet_handler);
375 msg = &nmp->nm_netmsg.nm_lmsg;
376 msg->u.ms_result32 = port; /* port is 16bits */
378 msg->u.ms_result32 |= DIV_INPUT;
380 msg->u.ms_result32 |= DIV_OUTPUT;
382 lwkt_sendmsg(cpu_portfn(0), &nmp->nm_netmsg.nm_lmsg);
385 div_packet(m, incoming, port);
389 * Deliver packet back into the IP processing machinery.
391 * If no address specified, or address is 0.0.0.0, send to ip_output();
392 * otherwise, send to ip_input() and mark as having been received on
393 * the interface with that address.
396 div_output(struct socket *so, struct mbuf *m,
397 struct sockaddr_in *sin, struct mbuf *control)
401 struct divert_info *divinfo;
404 m_freem(control); /* XXX */
407 * Prepare the tag for divert info. Note that a packet
408 * with a 0 tag in mh_data is effectively untagged,
409 * so we could optimize that case.
411 mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT, sizeof(*divinfo), MB_DONTWAIT);
416 m_tag_prepend(m, mtag);
418 /* Loopback avoidance and state recovery */
419 divinfo = m_tag_data(mtag);
421 divinfo->skipto = sin->sin_port;
425 /* Reinject packet into the system as incoming or outgoing */
426 if (DIV_IS_OUTPUT(sin)) {
427 struct ip *const ip = mtod(m, struct ip *);
429 /* Don't allow packet length sizes that will crash */
430 if ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len) {
435 /* Convert fields to host order for ip_output() */
436 ip->ip_len = ntohs(ip->ip_len);
437 ip->ip_off = ntohs(ip->ip_off);
439 /* Send packet to output processing */
440 ipstat.ips_rawout++; /* XXX */
441 error = ip_output(m, NULL, NULL,
442 (so->so_options & SO_DONTROUTE) |
443 IP_ALLOWBROADCAST | IP_RAWOUTPUT,
456 div_attach(struct socket *so, int proto, struct pru_attach_info *ai)
464 if ((error = priv_check_cred(ai->p_ucred, PRIV_ROOT, NULL_CRED_OKAY)) != 0)
467 error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit);
470 error = in_pcballoc(so, &divcbinfo);
473 inp = (struct inpcb *)so->so_pcb;
474 inp->inp_ip_p = proto;
475 inp->inp_vflag |= INP_IPV4;
476 inp->inp_flags |= INP_HDRINCL;
478 * The socket is always "connected" because
479 * we always know "where" to send the packet.
481 so->so_port = cpu0_soport(so, NULL, NULL);
482 so->so_state |= SS_ISCONNECTED;
487 div_detach(struct socket *so)
499 div_abort(struct socket *so)
501 soisdisconnected(so);
502 return div_detach(so);
506 div_disconnect(struct socket *so)
508 if (!(so->so_state & SS_ISCONNECTED))
510 return div_abort(so);
514 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
519 * in_pcbbind assumes that nam is a sockaddr_in
520 * and in_pcbbind requires a valid address. Since divert
521 * sockets don't we need to make sure the address is
522 * filled in properly.
523 * XXX -- divert should not be abusing in_pcbind
524 * and should probably have its own family.
526 if (nam->sa_family != AF_INET) {
527 error = EAFNOSUPPORT;
529 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
530 error = in_pcbbind(so->so_pcb, nam, td);
536 div_shutdown(struct socket *so)
543 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
544 struct mbuf *control, struct thread *td)
546 /* Length check already done in ip_mport() */
547 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf"));
550 return div_output(so, m, (struct sockaddr_in *)nam, control);
553 SYSCTL_DECL(_net_inet_divert);
554 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 0,
555 in_pcblist_global, "S,xinpcb", "List of active divert sockets");
557 struct pr_usrreqs div_usrreqs = {
558 .pru_abort = div_abort,
559 .pru_accept = pru_accept_notsupp,
560 .pru_attach = div_attach,
561 .pru_bind = div_bind,
562 .pru_connect = pru_connect_notsupp,
563 .pru_connect2 = pru_connect2_notsupp,
564 .pru_control = in_control,
565 .pru_detach = div_detach,
566 .pru_disconnect = div_disconnect,
567 .pru_listen = pru_listen_notsupp,
568 .pru_peeraddr = in_setpeeraddr,
569 .pru_rcvd = pru_rcvd_notsupp,
570 .pru_rcvoob = pru_rcvoob_notsupp,
571 .pru_send = div_send,
572 .pru_sense = pru_sense_null,
573 .pru_shutdown = div_shutdown,
574 .pru_sockaddr = in_setsockaddr,
575 .pru_sosend = sosend,
576 .pru_soreceive = soreceive
580 ip_divert_out(struct mbuf *m, int tee)
582 struct mbuf *clone = NULL;
583 struct ip *ip = mtod(m, struct ip *);
585 /* Clone packet if we're doing a 'tee' */
587 clone = m_dup(m, MB_DONTWAIT);
591 * delayed checksums are not currently compatible
592 * with divert sockets.
594 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
596 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
599 /* Restore packet header fields to original values */
600 ip->ip_len = htons(ip->ip_len);
601 ip->ip_off = htons(ip->ip_off);
603 /* Deliver packet to divert input routine */
606 /* If 'tee', continue with original packet */
611 ip_divert_in(struct mbuf *m, int tee)
613 struct mbuf *clone = NULL;
614 struct ip *ip = mtod(m, struct ip *);
617 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
618 const struct divert_info *divinfo;
623 * Only trust divert info in the fragment
626 frag_off = ip->ip_off << 3;
628 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
629 m_tag_delete(m, mtag);
633 * Attempt reassembly; if it succeeds, proceed.
634 * ip_reass() will return a different mbuf.
639 ip = mtod(m, struct ip *);
641 /* Caller need to redispatch the packet, if it is for us */
642 m->m_pkthdr.fw_flags |= FW_MBUF_REDISPATCH;
645 * Get the header length of the reassembled
648 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
651 * Restore original checksum before diverting
655 ip->ip_len = htons(ip->ip_len);
656 ip->ip_off = htons(ip->ip_off);
658 if (hlen == sizeof(struct ip))
659 ip->ip_sum = in_cksum_hdr(ip);
661 ip->ip_sum = in_cksum(m, hlen);
662 ip->ip_off = ntohs(ip->ip_off);
663 ip->ip_len = ntohs(ip->ip_len);
666 * Only use the saved divert info
668 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
670 /* Wrongly configured ipfw */
671 kprintf("ip_input no divert info\n");
675 divinfo = m_tag_data(mtag);
680 * Divert or tee packet to the divert protocol if
684 /* Clone packet if we're doing a 'tee' */
686 clone = m_dup(m, MB_DONTWAIT);
689 * Restore packet header fields to original
692 ip->ip_len = htons(ip->ip_len);
693 ip->ip_off = htons(ip->ip_off);
695 /* Deliver packet to divert input routine */
698 /* Catch invalid reference */
702 ipstat.ips_delivered++;
704 /* If 'tee', continue with original packet */
707 * Complete processing of the packet.
708 * XXX Better safe than sorry, remove the DIVERT tag.
710 mtag = m_tag_find(clone, PACKET_TAG_IPFW_DIVERT, NULL);
711 KKASSERT(mtag != NULL);
712 m_tag_delete(clone, mtag);
718 ip_divert(struct mbuf *m, int tee, int incoming)
723 ret = ip_divert_in(m, tee);
725 ret = ip_divert_out(m, tee);