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29 * $FreeBSD: src/sys/netinet/ip_divert.c,v 1.42.2.6 2003/01/23 21:06:45 sam Exp $
35 #include "opt_ipdivert.h"
36 #include "opt_ipsec.h"
39 #error "IPDIVERT requires INET."
42 #include <sys/param.h>
43 #include <sys/kernel.h>
44 #include <sys/malloc.h>
46 #include <sys/socket.h>
47 #include <sys/protosw.h>
48 #include <sys/socketvar.h>
49 #include <sys/socketvar2.h>
50 #include <sys/sysctl.h>
51 #include <sys/systm.h>
54 #include <sys/in_cksum.h>
56 #include <sys/msgport.h>
59 #include <net/route.h>
61 #include <net/netmsg2.h>
62 #include <net/netisr2.h>
63 #include <sys/thread2.h>
64 #include <sys/mplock2.h>
66 #include <netinet/in.h>
67 #include <netinet/in_systm.h>
68 #include <netinet/ip.h>
69 #include <netinet/in_pcb.h>
70 #include <netinet/in_var.h>
71 #include <netinet/ip_var.h>
72 #include <netinet/ip_divert.h>
79 * Allocate enough space to hold a full IP packet
81 #define DIVSNDQ (65536 + 100)
82 #define DIVRCVQ (65536 + 100)
84 #define DIV_IS_OUTPUT(sin) ((sin) == NULL || (sin)->sin_addr.s_addr == 0)
86 #define DIV_OUTPUT 0x10000
87 #define DIV_INPUT 0x20000
90 * Divert sockets work in conjunction with ipfw, see the divert(4)
91 * manpage for features.
92 * Internally, packets selected by ipfw in ip_input() or ip_output(),
93 * and never diverted before, are passed to the input queue of the
94 * divert socket with a given 'divert_port' number (as specified in
95 * the matching ipfw rule), and they are tagged with a 16 bit cookie
96 * (representing the rule number of the matching ipfw rule), which
97 * is passed to process reading from the socket.
99 * Packets written to the divert socket are again tagged with a cookie
100 * (usually the same as above) and a destination address.
101 * If the destination address is INADDR_ANY then the packet is
102 * treated as outgoing and sent to ip_output(), otherwise it is
103 * treated as incoming and sent to ip_input().
104 * In both cases, the packet is tagged with the cookie.
106 * On reinjection, processing in ip_input() and ip_output()
107 * will be exactly the same as for the original packet, except that
108 * ipfw processing will start at the rule number after the one
109 * written in the cookie (so, tagging a packet with a cookie of 0
110 * will cause it to be effectively considered as a standard packet).
113 /* Internal variables */
114 static struct inpcbinfo divcbinfo;
115 static struct inpcbportinfo divcbportinfo;
117 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */
118 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */
120 static struct mbuf *ip_divert(struct mbuf *, int, int);
123 * Initialize divert connection block queue.
128 in_pcbinfo_init(&divcbinfo, 0, FALSE);
129 in_pcbportinfo_init(&divcbportinfo, 1, FALSE, 0);
131 * XXX We don't use the hash list for divert IP, but it's easier
132 * to allocate a one entry hash list than it is to check all
133 * over the place for hashbase == NULL.
135 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask);
136 divcbinfo.portinfo = &divcbportinfo;
137 divcbinfo.wildcardhashbase = hashinit(1, M_PCB,
138 &divcbinfo.wildcardhashmask);
139 divcbinfo.ipi_size = sizeof(struct inpcb);
140 ip_divert_p = ip_divert;
144 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets
145 * with that protocol number to enter the system from the outside.
148 div_input(struct mbuf **mp, int *offp, int proto)
150 struct mbuf *m = *mp;
152 ipstat.ips_noproto++;
154 return(IPPROTO_DONE);
158 * Divert a packet by passing it up to the divert socket at port 'port'.
160 * Setup generic address and protocol structures for div_input routine,
161 * then pass them along with mbuf chain.
164 div_packet(struct mbuf *m, int incoming, int port)
166 struct sockaddr_in divsrc = { sizeof divsrc, AF_INET };
170 struct divert_info *divinfo;
173 KASSERT(&curthread->td_msgport == netisr_cpuport(0),
176 /* Locate the divert info */
177 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
178 divinfo = m_tag_data(mtag);
179 divsrc.sin_port = divinfo->skipto;
182 * Record receive interface address, if any.
183 * But only for incoming packets.
185 divsrc.sin_addr.s_addr = 0;
187 struct ifaddr_container *ifac;
189 /* Find IP address for receive interface */
190 TAILQ_FOREACH(ifac, &m->m_pkthdr.rcvif->if_addrheads[mycpuid],
192 struct ifaddr *ifa = ifac->ifa;
194 if (ifa->ifa_addr == NULL)
196 if (ifa->ifa_addr->sa_family != AF_INET)
199 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
204 * Record the incoming interface name whenever we have one.
206 if (m->m_pkthdr.rcvif) {
208 * Hide the actual interface name in there in the
209 * sin_zero array. XXX This needs to be moved to a
210 * different sockaddr type for divert, e.g.
211 * sockaddr_div with multiple fields like
212 * sockaddr_dl. Presently we have only 7 bytes
213 * but that will do for now as most interfaces
214 * are 4 or less + 2 or less bytes for unit.
215 * There is probably a faster way of doing this,
216 * possibly taking it from the sockaddr_dl on the iface.
217 * This solves the problem of a P2P link and a LAN interface
218 * having the same address, which can result in the wrong
219 * interface being assigned to the packet when fed back
220 * into the divert socket. Theoretically if the daemon saves
221 * and re-uses the sockaddr_in as suggested in the man pages,
222 * this iface name will come along for the ride.
223 * (see div_output for the other half of this.)
225 ksnprintf(divsrc.sin_zero, sizeof divsrc.sin_zero, "%s",
226 m->m_pkthdr.rcvif->if_xname);
229 /* Put packet on socket queue, if any */
231 nport = htons((u_int16_t)port);
234 * Following loop to locate the inpcb is MPSAFE since the inpcb
235 * insertion/removal happens on the same CPU (CPU0).
237 LIST_FOREACH(inp, &divcbinfo.pcblisthead, inp_list) {
238 if (inp->inp_flags & INP_PLACEMARKER)
240 if (inp->inp_lport == nport)
241 sa = inp->inp_socket;
244 lwkt_gettoken(&sa->so_rcv.ssb_token);
245 if (ssb_appendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m, NULL) == 0)
249 lwkt_reltoken(&sa->so_rcv.ssb_token);
252 ipstat.ips_noproto++;
253 ipstat.ips_delivered--;
258 div_packet_handler(netmsg_t msg)
261 int port, incoming = 0;
263 m = msg->packet.nm_packet;
265 port = msg->lmsg.u.ms_result32 & 0xffff;
266 if (msg->lmsg.u.ms_result32 & DIV_INPUT)
268 div_packet(m, incoming, port);
269 /* no reply, msg embedded in mbuf */
273 divert_packet(struct mbuf *m, int incoming)
276 struct divert_info *divinfo;
282 if (m->m_len < sizeof(struct ip) &&
283 (m = m_pullup(m, sizeof(struct ip))) == NULL)
286 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
287 KASSERT(mtag != NULL, ("%s no divert tag!", __func__));
288 divinfo = m_tag_data(mtag);
290 port = divinfo->port;
291 KASSERT(port != 0, ("%s: port=0", __func__));
294 struct netmsg_packet *nmp;
296 nmp = &m->m_hdr.mh_netmsg;
297 netmsg_init(&nmp->base, NULL, &netisr_apanic_rport,
298 0, div_packet_handler);
301 nmp->base.lmsg.u.ms_result32 = port; /* port is 16bits */
303 nmp->base.lmsg.u.ms_result32 |= DIV_INPUT;
305 nmp->base.lmsg.u.ms_result32 |= DIV_OUTPUT;
307 lwkt_sendmsg(netisr_cpuport(0), &nmp->base.lmsg);
309 div_packet(m, incoming, port);
314 * Deliver packet back into the IP processing machinery.
316 * If no address specified, or address is 0.0.0.0, send to ip_output();
317 * otherwise, send to ip_input() and mark as having been received on
318 * the interface with that address.
321 div_output(struct socket *so, struct mbuf *m,
322 struct sockaddr_in *sin, struct mbuf *control)
326 struct divert_info *divinfo;
328 KASSERT(&curthread->td_msgport == netisr_cpuport(0),
332 m_freem(control); /* XXX */
335 * Prepare the tag for divert info. Note that a packet
336 * with a 0 tag in mh_data is effectively untagged,
337 * so we could optimize that case.
339 mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT, sizeof(*divinfo), M_NOWAIT);
344 m_tag_prepend(m, mtag);
346 /* Loopback avoidance and state recovery */
347 divinfo = m_tag_data(mtag);
349 divinfo->skipto = sin->sin_port;
353 /* Reinject packet into the system as incoming or outgoing */
354 if (DIV_IS_OUTPUT(sin)) {
355 struct ip *const ip = mtod(m, struct ip *);
357 /* Don't allow packet length sizes that will crash */
358 if ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len) {
363 /* Convert fields to host order for ip_output() */
364 ip->ip_len = ntohs(ip->ip_len);
365 ip->ip_off = ntohs(ip->ip_off);
367 /* Send packet to output processing */
368 ipstat.ips_rawout++; /* XXX */
369 error = ip_output(m, NULL, NULL,
370 (so->so_options & SO_DONTROUTE) |
371 IP_ALLOWBROADCAST | IP_RAWOUTPUT,
384 div_attach(netmsg_t msg)
386 struct socket *so = msg->attach.base.nm_so;
387 int proto = msg->attach.nm_proto;
388 struct pru_attach_info *ai = msg->attach.nm_ai;
392 KASSERT(&curthread->td_msgport == netisr_cpuport(0),
398 error = priv_check_cred(ai->p_ucred, PRIV_ROOT, NULL_CRED_OKAY);
402 error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit);
405 error = in_pcballoc(so, &divcbinfo);
408 inp = (struct inpcb *)so->so_pcb;
409 inp->inp_ip_p = proto;
410 inp->inp_flags |= INP_HDRINCL;
412 * The socket is always "connected" because
413 * we always know "where" to send the packet.
415 sosetstate(so, SS_ISCONNECTED);
418 lwkt_replymsg(&msg->attach.base.lmsg, error);
422 div_detach(netmsg_t msg)
424 struct socket *so = msg->detach.base.nm_so;
427 KASSERT(&curthread->td_msgport == netisr_cpuport(0),
434 lwkt_replymsg(&msg->detach.base.lmsg, 0);
438 div_abort(netmsg_t msg)
441 * Divert socket does not support listen(2),
442 * so this should never be called.
444 panic("div_abort is called");
448 div_disconnect(netmsg_t msg)
450 struct socket *so = msg->disconnect.base.nm_so;
453 KASSERT(&curthread->td_msgport == netisr_cpuport(0),
456 if (so->so_state & SS_ISCONNECTED) {
457 soisdisconnected(so);
462 lwkt_replymsg(&msg->disconnect.base.lmsg, error);
466 div_bind(netmsg_t msg)
468 struct socket *so = msg->bind.base.nm_so;
469 struct sockaddr *nam = msg->bind.nm_nam;
472 KASSERT(&curthread->td_msgport == netisr_cpuport(0),
476 * in_pcbbind assumes that nam is a sockaddr_in
477 * and in_pcbbind requires a valid address. Since divert
478 * sockets don't we need to make sure the address is
479 * filled in properly.
480 * XXX -- divert should not be abusing in_pcbind
481 * and should probably have its own family.
483 if (nam->sa_family != AF_INET) {
484 error = EAFNOSUPPORT;
486 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
487 error = in_pcbbind(so->so_pcb, nam, msg->bind.nm_td);
489 lwkt_replymsg(&msg->bind.base.lmsg, error);
493 div_shutdown(netmsg_t msg)
495 struct socket *so = msg->shutdown.base.nm_so;
497 KASSERT(&curthread->td_msgport == netisr_cpuport(0),
502 lwkt_replymsg(&msg->shutdown.base.lmsg, 0);
506 div_send(netmsg_t msg)
508 struct socket *so = msg->send.base.nm_so;
509 struct mbuf *m = msg->send.nm_m;
510 struct sockaddr *nam = msg->send.nm_addr;
511 struct mbuf *control = msg->send.nm_control;
514 /* Length check already done in ip_hashfn() */
515 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf"));
518 error = div_output(so, m, (struct sockaddr_in *)nam, control);
519 lwkt_replymsg(&msg->send.base.lmsg, error);
522 SYSCTL_DECL(_net_inet_divert);
523 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 1,
524 in_pcblist_global, "S,xinpcb", "List of active divert sockets");
526 struct pr_usrreqs div_usrreqs = {
527 .pru_abort = div_abort,
528 .pru_accept = pr_generic_notsupp,
529 .pru_attach = div_attach,
530 .pru_bind = div_bind,
531 .pru_connect = pr_generic_notsupp,
532 .pru_connect2 = pr_generic_notsupp,
533 .pru_control = in_control_dispatch,
534 .pru_detach = div_detach,
535 .pru_disconnect = div_disconnect,
536 .pru_listen = pr_generic_notsupp,
537 .pru_peeraddr = in_setpeeraddr_dispatch,
538 .pru_rcvd = pr_generic_notsupp,
539 .pru_rcvoob = pr_generic_notsupp,
540 .pru_send = div_send,
541 .pru_sense = pru_sense_null,
542 .pru_shutdown = div_shutdown,
543 .pru_sockaddr = in_setsockaddr_dispatch,
544 .pru_sosend = sosend,
545 .pru_soreceive = soreceive
549 ip_divert_out(struct mbuf *m, int tee)
551 struct mbuf *clone = NULL;
552 struct ip *ip = mtod(m, struct ip *);
554 /* Clone packet if we're doing a 'tee' */
556 clone = m_dup(m, M_NOWAIT);
560 * delayed checksums are not currently compatible
561 * with divert sockets.
563 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
565 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
568 /* Restore packet header fields to original values */
569 ip->ip_len = htons(ip->ip_len);
570 ip->ip_off = htons(ip->ip_off);
572 /* Deliver packet to divert input routine */
575 /* If 'tee', continue with original packet */
580 ip_divert_in(struct mbuf *m, int tee)
582 struct mbuf *clone = NULL;
583 struct ip *ip = mtod(m, struct ip *);
586 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
587 const struct divert_info *divinfo;
592 * Only trust divert info in the fragment
595 frag_off = ip->ip_off << 3;
597 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
598 m_tag_delete(m, mtag);
602 * Attempt reassembly; if it succeeds, proceed.
603 * ip_reass() will return a different mbuf.
608 ip = mtod(m, struct ip *);
610 /* Caller need to redispatch the packet, if it is for us */
611 m->m_pkthdr.fw_flags |= FW_MBUF_REDISPATCH;
614 * Get the header length of the reassembled
617 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
620 * Restore original checksum before diverting
624 ip->ip_len = htons(ip->ip_len);
625 ip->ip_off = htons(ip->ip_off);
627 if (hlen == sizeof(struct ip))
628 ip->ip_sum = in_cksum_hdr(ip);
630 ip->ip_sum = in_cksum(m, hlen);
631 ip->ip_off = ntohs(ip->ip_off);
632 ip->ip_len = ntohs(ip->ip_len);
635 * Only use the saved divert info
637 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
639 /* Wrongly configured ipfw */
640 kprintf("ip_input no divert info\n");
644 divinfo = m_tag_data(mtag);
649 * Divert or tee packet to the divert protocol if
653 /* Clone packet if we're doing a 'tee' */
655 clone = m_dup(m, M_NOWAIT);
658 * Restore packet header fields to original
661 ip->ip_len = htons(ip->ip_len);
662 ip->ip_off = htons(ip->ip_off);
664 /* Deliver packet to divert input routine */
667 /* Catch invalid reference */
671 ipstat.ips_delivered++;
673 /* If 'tee', continue with original packet */
676 * Complete processing of the packet.
677 * XXX Better safe than sorry, remove the DIVERT tag.
679 mtag = m_tag_find(clone, PACKET_TAG_IPFW_DIVERT, NULL);
680 KKASSERT(mtag != NULL);
681 m_tag_delete(clone, mtag);
687 ip_divert(struct mbuf *m, int tee, int incoming)
692 ret = ip_divert_in(m, tee);
694 ret = ip_divert_out(m, tee);