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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 $
39 #include "opt_ipdivert.h"
40 #include "opt_ipsec.h"
43 #error "IPDIVERT requires INET."
46 #include <sys/param.h>
47 #include <sys/kernel.h>
48 #include <sys/malloc.h>
50 #include <sys/socket.h>
51 #include <sys/protosw.h>
52 #include <sys/socketvar.h>
53 #include <sys/socketvar2.h>
54 #include <sys/sysctl.h>
55 #include <sys/systm.h>
58 #include <sys/in_cksum.h>
60 #include <sys/msgport.h>
63 #include <net/route.h>
65 #include <net/netmsg2.h>
66 #include <sys/thread2.h>
67 #include <sys/mplock2.h>
69 #include <netinet/in.h>
70 #include <netinet/in_systm.h>
71 #include <netinet/ip.h>
72 #include <netinet/in_pcb.h>
73 #include <netinet/in_var.h>
74 #include <netinet/ip_var.h>
75 #include <netinet/ip_divert.h>
82 * Allocate enough space to hold a full IP packet
84 #define DIVSNDQ (65536 + 100)
85 #define DIVRCVQ (65536 + 100)
87 #define DIV_IS_OUTPUT(sin) ((sin) == NULL || (sin)->sin_addr.s_addr == 0)
89 #define DIV_OUTPUT 0x10000
90 #define DIV_INPUT 0x20000
93 * Divert sockets work in conjunction with ipfw, see the divert(4)
94 * manpage for features.
95 * Internally, packets selected by ipfw in ip_input() or ip_output(),
96 * and never diverted before, are passed to the input queue of the
97 * divert socket with a given 'divert_port' number (as specified in
98 * the matching ipfw rule), and they are tagged with a 16 bit cookie
99 * (representing the rule number of the matching ipfw rule), which
100 * is passed to process reading from the socket.
102 * Packets written to the divert socket are again tagged with a cookie
103 * (usually the same as above) and a destination address.
104 * If the destination address is INADDR_ANY then the packet is
105 * treated as outgoing and sent to ip_output(), otherwise it is
106 * treated as incoming and sent to ip_input().
107 * In both cases, the packet is tagged with the cookie.
109 * On reinjection, processing in ip_input() and ip_output()
110 * will be exactly the same as for the original packet, except that
111 * ipfw processing will start at the rule number after the one
112 * written in the cookie (so, tagging a packet with a cookie of 0
113 * will cause it to be effectively considered as a standard packet).
116 /* Internal variables */
117 static struct inpcbinfo divcbinfo;
119 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */
120 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */
122 static struct mbuf *ip_divert(struct mbuf *, int, int);
124 static struct lwkt_token div_token = LWKT_TOKEN_INITIALIZER(div_token);
127 * Initialize divert connection block queue.
132 in_pcbinfo_init(&divcbinfo);
134 * XXX We don't use the hash list for divert IP, but it's easier
135 * to allocate a one entry hash list than it is to check all
136 * over the place for hashbase == NULL.
138 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask);
139 divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask);
140 divcbinfo.wildcardhashbase = hashinit(1, M_PCB,
141 &divcbinfo.wildcardhashmask);
142 divcbinfo.ipi_size = sizeof(struct inpcb);
143 ip_divert_p = ip_divert;
147 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets
148 * with that protocol number to enter the system from the outside.
151 div_input(struct mbuf **mp, int *offp, int proto)
153 struct mbuf *m = *mp;
155 ipstat.ips_noproto++;
157 return(IPPROTO_DONE);
161 * Divert a packet by passing it up to the divert socket at port 'port'.
163 * Setup generic address and protocol structures for div_input routine,
164 * then pass them along with mbuf chain.
167 div_packet(struct mbuf *m, int incoming, int port)
169 struct sockaddr_in divsrc = { sizeof divsrc, AF_INET };
173 struct divert_info *divinfo;
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);
235 * Following loop to locate the inpcb is MPSAFE since the inpcb
236 * insertion/removal happens on the same CPU (CPU0), however,
237 * saving/testing the socket pointer is not MPSAFE. So we still
238 * need to hold BGL here.
240 lwkt_gettoken(&div_token);
241 LIST_FOREACH(inp, &divcbinfo.pcblisthead, inp_list) {
242 if (inp->inp_flags & INP_PLACEMARKER)
244 if (inp->inp_lport == nport)
245 sa = inp->inp_socket;
248 lwkt_gettoken(&sa->so_rcv.ssb_token);
249 if (ssb_appendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc, m, NULL) == 0)
253 lwkt_reltoken(&sa->so_rcv.ssb_token);
256 ipstat.ips_noproto++;
257 ipstat.ips_delivered--;
259 lwkt_reltoken(&div_token);
265 div_packet_handler(netmsg_t msg)
268 int port, incoming = 0;
270 m = msg->packet.nm_packet;
272 port = msg->lmsg.u.ms_result32 & 0xffff;
273 if (msg->lmsg.u.ms_result32 & DIV_INPUT)
275 div_packet(m, incoming, port);
276 /* no reply, msg embedded in mbuf */
282 divert_packet(struct mbuf *m, int incoming)
285 struct divert_info *divinfo;
291 if (m->m_len < sizeof(struct ip) &&
292 (m = m_pullup(m, sizeof(struct ip))) == NULL)
295 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
296 KASSERT(mtag != NULL, ("%s no divert tag!", __func__));
297 divinfo = m_tag_data(mtag);
299 port = divinfo->port;
300 KASSERT(port != 0, ("%s: port=0", __func__));
304 struct netmsg_packet *nmp;
306 nmp = &m->m_hdr.mh_netmsg;
307 netmsg_init(&nmp->base, NULL, &netisr_apanic_rport,
308 0, div_packet_handler);
311 nmp->base.lmsg.u.ms_result32 = port; /* port is 16bits */
313 nmp->base.lmsg.u.ms_result32 |= DIV_INPUT;
315 nmp->base.lmsg.u.ms_result32 |= DIV_OUTPUT;
317 lwkt_sendmsg(cpu_portfn(0), &nmp->base.lmsg);
319 div_packet(m, incoming, port);
322 div_packet(m, incoming, port);
327 * Deliver packet back into the IP processing machinery.
329 * If no address specified, or address is 0.0.0.0, send to ip_output();
330 * otherwise, send to ip_input() and mark as having been received on
331 * the interface with that address.
334 div_output(struct socket *so, struct mbuf *m,
335 struct sockaddr_in *sin, struct mbuf *control)
339 struct divert_info *divinfo;
342 m_freem(control); /* XXX */
345 * Prepare the tag for divert info. Note that a packet
346 * with a 0 tag in mh_data is effectively untagged,
347 * so we could optimize that case.
349 mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT, sizeof(*divinfo), MB_DONTWAIT);
354 m_tag_prepend(m, mtag);
356 /* Loopback avoidance and state recovery */
357 divinfo = m_tag_data(mtag);
359 divinfo->skipto = sin->sin_port;
363 /* Reinject packet into the system as incoming or outgoing */
364 if (DIV_IS_OUTPUT(sin)) {
365 struct ip *const ip = mtod(m, struct ip *);
367 /* Don't allow packet length sizes that will crash */
368 if ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len) {
373 /* Convert fields to host order for ip_output() */
374 ip->ip_len = ntohs(ip->ip_len);
375 ip->ip_off = ntohs(ip->ip_off);
377 /* Send packet to output processing */
378 ipstat.ips_rawout++; /* XXX */
379 error = ip_output(m, NULL, NULL,
380 (so->so_options & SO_DONTROUTE) |
381 IP_ALLOWBROADCAST | IP_RAWOUTPUT,
394 div_attach(netmsg_t msg)
396 struct socket *so = msg->attach.base.nm_so;
397 int proto = msg->attach.nm_proto;
398 struct pru_attach_info *ai = msg->attach.nm_ai;
405 error = priv_check_cred(ai->p_ucred, PRIV_ROOT, NULL_CRED_OKAY);
409 error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit);
412 lwkt_gettoken(&div_token);
413 sosetport(so, cpu_portfn(0));
414 error = in_pcballoc(so, &divcbinfo);
416 lwkt_reltoken(&div_token);
419 inp = (struct inpcb *)so->so_pcb;
420 inp->inp_ip_p = proto;
421 inp->inp_vflag |= INP_IPV4;
422 inp->inp_flags |= INP_HDRINCL;
424 * The socket is always "connected" because
425 * we always know "where" to send the packet.
427 sosetstate(so, SS_ISCONNECTED);
428 lwkt_reltoken(&div_token);
431 lwkt_replymsg(&msg->attach.base.lmsg, error);
435 div_detach(netmsg_t msg)
437 struct socket *so = msg->detach.base.nm_so;
444 lwkt_replymsg(&msg->detach.base.lmsg, 0);
448 * NOTE: (so) is referenced from soabort*() and netmsg_pru_abort()
449 * will sofree() it when we return.
452 div_abort(netmsg_t msg)
454 struct socket *so = msg->abort.base.nm_so;
456 soisdisconnected(so);
458 /* msg invalid now */
462 div_disconnect(netmsg_t msg)
464 struct socket *so = msg->disconnect.base.nm_so;
467 if (so->so_state & SS_ISCONNECTED) {
470 /* msg invalid now */
475 lwkt_replymsg(&msg->disconnect.base.lmsg, error);
479 div_bind(netmsg_t msg)
481 struct socket *so = msg->bind.base.nm_so;
482 struct sockaddr *nam = msg->bind.nm_nam;
486 * in_pcbbind assumes that nam is a sockaddr_in
487 * and in_pcbbind requires a valid address. Since divert
488 * sockets don't we need to make sure the address is
489 * filled in properly.
490 * XXX -- divert should not be abusing in_pcbind
491 * and should probably have its own family.
493 if (nam->sa_family != AF_INET) {
494 error = EAFNOSUPPORT;
496 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
497 error = in_pcbbind(so->so_pcb, nam, msg->bind.nm_td);
499 lwkt_replymsg(&msg->bind.base.lmsg, error);
503 div_shutdown(netmsg_t msg)
505 struct socket *so = msg->shutdown.base.nm_so;
509 lwkt_replymsg(&msg->shutdown.base.lmsg, 0);
513 div_send(netmsg_t msg)
515 struct socket *so = msg->send.base.nm_so;
516 struct mbuf *m = msg->send.nm_m;
517 struct sockaddr *nam = msg->send.nm_addr;
518 struct mbuf *control = msg->send.nm_control;
521 /* Length check already done in ip_cpufn() */
522 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf"));
525 error = div_output(so, m, (struct sockaddr_in *)nam, control);
526 lwkt_replymsg(&msg->send.base.lmsg, error);
529 SYSCTL_DECL(_net_inet_divert);
530 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 0,
531 in_pcblist_global, "S,xinpcb", "List of active divert sockets");
533 struct pr_usrreqs div_usrreqs = {
534 .pru_abort = div_abort,
535 .pru_accept = pr_generic_notsupp,
536 .pru_attach = div_attach,
537 .pru_bind = div_bind,
538 .pru_connect = pr_generic_notsupp,
539 .pru_connect2 = pr_generic_notsupp,
540 .pru_control = in_control_dispatch,
541 .pru_detach = div_detach,
542 .pru_disconnect = div_disconnect,
543 .pru_listen = pr_generic_notsupp,
544 .pru_peeraddr = in_setpeeraddr_dispatch,
545 .pru_rcvd = pr_generic_notsupp,
546 .pru_rcvoob = pr_generic_notsupp,
547 .pru_send = div_send,
548 .pru_sense = pru_sense_null,
549 .pru_shutdown = div_shutdown,
550 .pru_sockaddr = in_setsockaddr_dispatch,
551 .pru_sosend = sosend,
552 .pru_soreceive = soreceive
556 ip_divert_out(struct mbuf *m, int tee)
558 struct mbuf *clone = NULL;
559 struct ip *ip = mtod(m, struct ip *);
561 /* Clone packet if we're doing a 'tee' */
563 clone = m_dup(m, MB_DONTWAIT);
567 * delayed checksums are not currently compatible
568 * with divert sockets.
570 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
572 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
575 /* Restore packet header fields to original values */
576 ip->ip_len = htons(ip->ip_len);
577 ip->ip_off = htons(ip->ip_off);
579 /* Deliver packet to divert input routine */
582 /* If 'tee', continue with original packet */
587 ip_divert_in(struct mbuf *m, int tee)
589 struct mbuf *clone = NULL;
590 struct ip *ip = mtod(m, struct ip *);
593 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
594 const struct divert_info *divinfo;
599 * Only trust divert info in the fragment
602 frag_off = ip->ip_off << 3;
604 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
605 m_tag_delete(m, mtag);
609 * Attempt reassembly; if it succeeds, proceed.
610 * ip_reass() will return a different mbuf.
615 ip = mtod(m, struct ip *);
617 /* Caller need to redispatch the packet, if it is for us */
618 m->m_pkthdr.fw_flags |= FW_MBUF_REDISPATCH;
621 * Get the header length of the reassembled
624 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
627 * Restore original checksum before diverting
631 ip->ip_len = htons(ip->ip_len);
632 ip->ip_off = htons(ip->ip_off);
634 if (hlen == sizeof(struct ip))
635 ip->ip_sum = in_cksum_hdr(ip);
637 ip->ip_sum = in_cksum(m, hlen);
638 ip->ip_off = ntohs(ip->ip_off);
639 ip->ip_len = ntohs(ip->ip_len);
642 * Only use the saved divert info
644 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
646 /* Wrongly configured ipfw */
647 kprintf("ip_input no divert info\n");
651 divinfo = m_tag_data(mtag);
656 * Divert or tee packet to the divert protocol if
660 /* Clone packet if we're doing a 'tee' */
662 clone = m_dup(m, MB_DONTWAIT);
665 * Restore packet header fields to original
668 ip->ip_len = htons(ip->ip_len);
669 ip->ip_off = htons(ip->ip_off);
671 /* Deliver packet to divert input routine */
674 /* Catch invalid reference */
678 ipstat.ips_delivered++;
680 /* If 'tee', continue with original packet */
683 * Complete processing of the packet.
684 * XXX Better safe than sorry, remove the DIVERT tag.
686 mtag = m_tag_find(clone, PACKET_TAG_IPFW_DIVERT, NULL);
687 KKASSERT(mtag != NULL);
688 m_tag_delete(clone, mtag);
694 ip_divert(struct mbuf *m, int tee, int incoming)
699 ret = ip_divert_in(m, tee);
701 ret = ip_divert_out(m, tee);