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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 * Divert a packet by passing it up to the divert socket at port 'port'.
169 * Setup generic address and protocol structures for div_input routine,
170 * then pass them along with mbuf chain.
173 div_packet(struct mbuf *m, int incoming, int port)
175 struct sockaddr_in divsrc = { sizeof divsrc, AF_INET };
179 struct divert_info *divinfo;
182 /* Locate the divert info */
183 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
184 divinfo = m_tag_data(mtag);
185 divsrc.sin_port = divinfo->skipto;
188 * Record receive interface address, if any.
189 * But only for incoming packets.
191 divsrc.sin_addr.s_addr = 0;
193 struct ifaddr_container *ifac;
195 /* Find IP address for receive interface */
196 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid],
198 struct ifaddr *ifa = ifac->ifa;
200 if (ifa->ifa_addr == NULL)
202 if (ifa->ifa_addr->sa_family != AF_INET)
205 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
210 * Record the incoming interface name whenever we have one.
212 if (m->m_pkthdr.rcvif) {
214 * Hide the actual interface name in there in the
215 * sin_zero array. XXX This needs to be moved to a
216 * different sockaddr type for divert, e.g.
217 * sockaddr_div with multiple fields like
218 * sockaddr_dl. Presently we have only 7 bytes
219 * but that will do for now as most interfaces
220 * are 4 or less + 2 or less bytes for unit.
221 * There is probably a faster way of doing this,
222 * possibly taking it from the sockaddr_dl on the iface.
223 * This solves the problem of a P2P link and a LAN interface
224 * having the same address, which can result in the wrong
225 * interface being assigned to the packet when fed back
226 * into the divert socket. Theoretically if the daemon saves
227 * and re-uses the sockaddr_in as suggested in the man pages,
228 * this iface name will come along for the ride.
229 * (see div_output for the other half of this.)
231 ksnprintf(divsrc.sin_zero, sizeof divsrc.sin_zero,
232 m->m_pkthdr.rcvif->if_xname);
235 /* Put packet on socket queue, if any */
237 nport = htons((u_int16_t)port);
241 * Following loop to locate the inpcb is MPSAFE since the inpcb
242 * insertion/removal happens on the same CPU (CPU0), however,
243 * saving/testing the socket pointer is not MPSAFE. So we still
244 * need to hold BGL here.
246 lwkt_gettoken(&div_token);
247 LIST_FOREACH(inp, &divcbinfo.pcblisthead, inp_list) {
248 if (inp->inp_flags & INP_PLACEMARKER)
250 if (inp->inp_lport == nport)
251 sa = inp->inp_socket;
254 lwkt_gettoken(&sa->so_rcv.ssb_token);
255 if (ssb_appendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m, NULL) == 0)
259 lwkt_reltoken(&sa->so_rcv.ssb_token);
262 ipstat.ips_noproto++;
263 ipstat.ips_delivered--;
265 lwkt_reltoken(&div_token);
271 div_packet_handler(netmsg_t msg)
274 int port, incoming = 0;
276 m = msg->packet.nm_packet;
278 port = msg->lmsg.u.ms_result32 & 0xffff;
279 if (msg->lmsg.u.ms_result32 & DIV_INPUT)
281 div_packet(m, incoming, port);
282 /* no reply, msg embedded in mbuf */
288 divert_packet(struct mbuf *m, int incoming)
291 struct divert_info *divinfo;
297 if (m->m_len < sizeof(struct ip) &&
298 (m = m_pullup(m, sizeof(struct ip))) == NULL)
301 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
302 KASSERT(mtag != NULL, ("%s no divert tag!", __func__));
303 divinfo = m_tag_data(mtag);
305 port = divinfo->port;
306 KASSERT(port != 0, ("%s: port=0", __func__));
310 struct netmsg_packet *nmp;
312 nmp = &m->m_hdr.mh_netmsg;
313 netmsg_init(&nmp->base, NULL, &netisr_apanic_rport,
314 0, div_packet_handler);
317 nmp->base.lmsg.u.ms_result32 = port; /* port is 16bits */
319 nmp->base.lmsg.u.ms_result32 |= DIV_INPUT;
321 nmp->base.lmsg.u.ms_result32 |= DIV_OUTPUT;
323 lwkt_sendmsg(cpu_portfn(0), &nmp->base.lmsg);
325 div_packet(m, incoming, port);
328 div_packet(m, incoming, port);
333 * Deliver packet back into the IP processing machinery.
335 * If no address specified, or address is 0.0.0.0, send to ip_output();
336 * otherwise, send to ip_input() and mark as having been received on
337 * the interface with that address.
340 div_output(struct socket *so, struct mbuf *m,
341 struct sockaddr_in *sin, struct mbuf *control)
345 struct divert_info *divinfo;
348 m_freem(control); /* XXX */
351 * Prepare the tag for divert info. Note that a packet
352 * with a 0 tag in mh_data is effectively untagged,
353 * so we could optimize that case.
355 mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT, sizeof(*divinfo), MB_DONTWAIT);
360 m_tag_prepend(m, mtag);
362 /* Loopback avoidance and state recovery */
363 divinfo = m_tag_data(mtag);
365 divinfo->skipto = sin->sin_port;
369 /* Reinject packet into the system as incoming or outgoing */
370 if (DIV_IS_OUTPUT(sin)) {
371 struct ip *const ip = mtod(m, struct ip *);
373 /* Don't allow packet length sizes that will crash */
374 if ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len) {
379 /* Convert fields to host order for ip_output() */
380 ip->ip_len = ntohs(ip->ip_len);
381 ip->ip_off = ntohs(ip->ip_off);
383 /* Send packet to output processing */
384 ipstat.ips_rawout++; /* XXX */
385 error = ip_output(m, NULL, NULL,
386 (so->so_options & SO_DONTROUTE) |
387 IP_ALLOWBROADCAST | IP_RAWOUTPUT,
400 div_attach(netmsg_t msg)
402 struct socket *so = msg->attach.base.nm_so;
403 int proto = msg->attach.nm_proto;
404 struct pru_attach_info *ai = msg->attach.nm_ai;
411 error = priv_check_cred(ai->p_ucred, PRIV_ROOT, NULL_CRED_OKAY);
415 error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit);
418 lwkt_gettoken(&div_token);
419 sosetport(so, cpu_portfn(0));
420 error = in_pcballoc(so, &divcbinfo);
422 lwkt_reltoken(&div_token);
425 inp = (struct inpcb *)so->so_pcb;
426 inp->inp_ip_p = proto;
427 inp->inp_vflag |= INP_IPV4;
428 inp->inp_flags |= INP_HDRINCL;
430 * The socket is always "connected" because
431 * we always know "where" to send the packet.
433 sosetstate(so, SS_ISCONNECTED);
434 lwkt_reltoken(&div_token);
437 lwkt_replymsg(&msg->attach.base.lmsg, error);
441 div_detach(netmsg_t msg)
443 struct socket *so = msg->detach.base.nm_so;
450 lwkt_replymsg(&msg->detach.base.lmsg, 0);
454 * NOTE: (so) is referenced from soabort*() and netmsg_pru_abort()
455 * will sofree() it when we return.
458 div_abort(netmsg_t msg)
460 struct socket *so = msg->abort.base.nm_so;
462 soisdisconnected(so);
464 /* msg invalid now */
468 div_disconnect(netmsg_t msg)
470 struct socket *so = msg->disconnect.base.nm_so;
473 if (so->so_state & SS_ISCONNECTED) {
476 /* msg invalid now */
481 lwkt_replymsg(&msg->disconnect.base.lmsg, error);
485 div_bind(netmsg_t msg)
487 struct socket *so = msg->bind.base.nm_so;
488 struct sockaddr *nam = msg->bind.nm_nam;
492 * in_pcbbind assumes that nam is a sockaddr_in
493 * and in_pcbbind requires a valid address. Since divert
494 * sockets don't we need to make sure the address is
495 * filled in properly.
496 * XXX -- divert should not be abusing in_pcbind
497 * and should probably have its own family.
499 if (nam->sa_family != AF_INET) {
500 error = EAFNOSUPPORT;
502 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
503 error = in_pcbbind(so->so_pcb, nam, msg->bind.nm_td);
505 lwkt_replymsg(&msg->bind.base.lmsg, error);
509 div_shutdown(netmsg_t msg)
511 struct socket *so = msg->shutdown.base.nm_so;
515 lwkt_replymsg(&msg->shutdown.base.lmsg, 0);
519 div_send(netmsg_t msg)
521 struct socket *so = msg->send.base.nm_so;
522 struct mbuf *m = msg->send.nm_m;
523 struct sockaddr *nam = msg->send.nm_addr;
524 struct mbuf *control = msg->send.nm_control;
527 /* Length check already done in ip_cpufn() */
528 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf"));
531 error = div_output(so, m, (struct sockaddr_in *)nam, control);
532 lwkt_replymsg(&msg->send.base.lmsg, error);
535 SYSCTL_DECL(_net_inet_divert);
536 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 0,
537 in_pcblist_global, "S,xinpcb", "List of active divert sockets");
539 struct pr_usrreqs div_usrreqs = {
540 .pru_abort = div_abort,
541 .pru_accept = pr_generic_notsupp,
542 .pru_attach = div_attach,
543 .pru_bind = div_bind,
544 .pru_connect = pr_generic_notsupp,
545 .pru_connect2 = pr_generic_notsupp,
546 .pru_control = in_control_dispatch,
547 .pru_detach = div_detach,
548 .pru_disconnect = div_disconnect,
549 .pru_listen = pr_generic_notsupp,
550 .pru_peeraddr = in_setpeeraddr_dispatch,
551 .pru_rcvd = pr_generic_notsupp,
552 .pru_rcvoob = pr_generic_notsupp,
553 .pru_send = div_send,
554 .pru_sense = pru_sense_null,
555 .pru_shutdown = div_shutdown,
556 .pru_sockaddr = in_setsockaddr_dispatch,
557 .pru_sosend = sosend,
558 .pru_soreceive = soreceive
562 ip_divert_out(struct mbuf *m, int tee)
564 struct mbuf *clone = NULL;
565 struct ip *ip = mtod(m, struct ip *);
567 /* Clone packet if we're doing a 'tee' */
569 clone = m_dup(m, MB_DONTWAIT);
573 * delayed checksums are not currently compatible
574 * with divert sockets.
576 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
578 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
581 /* Restore packet header fields to original values */
582 ip->ip_len = htons(ip->ip_len);
583 ip->ip_off = htons(ip->ip_off);
585 /* Deliver packet to divert input routine */
588 /* If 'tee', continue with original packet */
593 ip_divert_in(struct mbuf *m, int tee)
595 struct mbuf *clone = NULL;
596 struct ip *ip = mtod(m, struct ip *);
599 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
600 const struct divert_info *divinfo;
605 * Only trust divert info in the fragment
608 frag_off = ip->ip_off << 3;
610 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
611 m_tag_delete(m, mtag);
615 * Attempt reassembly; if it succeeds, proceed.
616 * ip_reass() will return a different mbuf.
621 ip = mtod(m, struct ip *);
623 /* Caller need to redispatch the packet, if it is for us */
624 m->m_pkthdr.fw_flags |= FW_MBUF_REDISPATCH;
627 * Get the header length of the reassembled
630 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
633 * Restore original checksum before diverting
637 ip->ip_len = htons(ip->ip_len);
638 ip->ip_off = htons(ip->ip_off);
640 if (hlen == sizeof(struct ip))
641 ip->ip_sum = in_cksum_hdr(ip);
643 ip->ip_sum = in_cksum(m, hlen);
644 ip->ip_off = ntohs(ip->ip_off);
645 ip->ip_len = ntohs(ip->ip_len);
648 * Only use the saved divert info
650 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
652 /* Wrongly configured ipfw */
653 kprintf("ip_input no divert info\n");
657 divinfo = m_tag_data(mtag);
662 * Divert or tee packet to the divert protocol if
666 /* Clone packet if we're doing a 'tee' */
668 clone = m_dup(m, MB_DONTWAIT);
671 * Restore packet header fields to original
674 ip->ip_len = htons(ip->ip_len);
675 ip->ip_off = htons(ip->ip_off);
677 /* Deliver packet to divert input routine */
680 /* Catch invalid reference */
684 ipstat.ips_delivered++;
686 /* If 'tee', continue with original packet */
689 * Complete processing of the packet.
690 * XXX Better safe than sorry, remove the DIVERT tag.
692 mtag = m_tag_find(clone, PACKET_TAG_IPFW_DIVERT, NULL);
693 KKASSERT(mtag != NULL);
694 m_tag_delete(clone, mtag);
700 ip_divert(struct mbuf *m, int tee, int incoming)
705 ret = ip_divert_in(m, tee);
707 ret = ip_divert_out(m, tee);