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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);
263 div_packet_handler(netmsg_t msg)
266 int port, incoming = 0;
268 m = msg->packet.nm_packet;
270 port = msg->lmsg.u.ms_result32 & 0xffff;
271 if (msg->lmsg.u.ms_result32 & DIV_INPUT)
273 div_packet(m, incoming, port);
274 /* no reply, msg embedded in mbuf */
278 divert_packet(struct mbuf *m, int incoming)
281 struct divert_info *divinfo;
287 if (m->m_len < sizeof(struct ip) &&
288 (m = m_pullup(m, sizeof(struct ip))) == NULL)
291 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
292 KASSERT(mtag != NULL, ("%s no divert tag!", __func__));
293 divinfo = m_tag_data(mtag);
295 port = divinfo->port;
296 KASSERT(port != 0, ("%s: port=0", __func__));
299 struct netmsg_packet *nmp;
301 nmp = &m->m_hdr.mh_netmsg;
302 netmsg_init(&nmp->base, NULL, &netisr_apanic_rport,
303 0, div_packet_handler);
306 nmp->base.lmsg.u.ms_result32 = port; /* port is 16bits */
308 nmp->base.lmsg.u.ms_result32 |= DIV_INPUT;
310 nmp->base.lmsg.u.ms_result32 |= DIV_OUTPUT;
312 lwkt_sendmsg(netisr_portfn(0), &nmp->base.lmsg);
314 div_packet(m, incoming, port);
319 * Deliver packet back into the IP processing machinery.
321 * If no address specified, or address is 0.0.0.0, send to ip_output();
322 * otherwise, send to ip_input() and mark as having been received on
323 * the interface with that address.
326 div_output(struct socket *so, struct mbuf *m,
327 struct sockaddr_in *sin, struct mbuf *control)
331 struct divert_info *divinfo;
334 m_freem(control); /* XXX */
337 * Prepare the tag for divert info. Note that a packet
338 * with a 0 tag in mh_data is effectively untagged,
339 * so we could optimize that case.
341 mtag = m_tag_get(PACKET_TAG_IPFW_DIVERT, sizeof(*divinfo), MB_DONTWAIT);
346 m_tag_prepend(m, mtag);
348 /* Loopback avoidance and state recovery */
349 divinfo = m_tag_data(mtag);
351 divinfo->skipto = sin->sin_port;
355 /* Reinject packet into the system as incoming or outgoing */
356 if (DIV_IS_OUTPUT(sin)) {
357 struct ip *const ip = mtod(m, struct ip *);
359 /* Don't allow packet length sizes that will crash */
360 if ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len) {
365 /* Convert fields to host order for ip_output() */
366 ip->ip_len = ntohs(ip->ip_len);
367 ip->ip_off = ntohs(ip->ip_off);
369 /* Send packet to output processing */
370 ipstat.ips_rawout++; /* XXX */
371 error = ip_output(m, NULL, NULL,
372 (so->so_options & SO_DONTROUTE) |
373 IP_ALLOWBROADCAST | IP_RAWOUTPUT,
386 div_attach(netmsg_t msg)
388 struct socket *so = msg->attach.base.nm_so;
389 int proto = msg->attach.nm_proto;
390 struct pru_attach_info *ai = msg->attach.nm_ai;
397 error = priv_check_cred(ai->p_ucred, PRIV_ROOT, NULL_CRED_OKAY);
401 error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit);
404 lwkt_gettoken(&div_token);
405 sosetport(so, netisr_portfn(0));
406 error = in_pcballoc(so, &divcbinfo);
408 lwkt_reltoken(&div_token);
411 inp = (struct inpcb *)so->so_pcb;
412 inp->inp_ip_p = proto;
413 inp->inp_vflag |= INP_IPV4;
414 inp->inp_flags |= INP_HDRINCL;
416 * The socket is always "connected" because
417 * we always know "where" to send the packet.
419 sosetstate(so, SS_ISCONNECTED);
420 lwkt_reltoken(&div_token);
423 lwkt_replymsg(&msg->attach.base.lmsg, error);
427 div_detach(netmsg_t msg)
429 struct socket *so = msg->detach.base.nm_so;
436 lwkt_replymsg(&msg->detach.base.lmsg, 0);
440 * NOTE: (so) is referenced from soabort*() and netmsg_pru_abort()
441 * will sofree() it when we return.
444 div_abort(netmsg_t msg)
446 struct socket *so = msg->abort.base.nm_so;
448 soisdisconnected(so);
450 /* msg invalid now */
454 div_disconnect(netmsg_t msg)
456 struct socket *so = msg->disconnect.base.nm_so;
459 if (so->so_state & SS_ISCONNECTED) {
462 /* msg invalid now */
467 lwkt_replymsg(&msg->disconnect.base.lmsg, error);
471 div_bind(netmsg_t msg)
473 struct socket *so = msg->bind.base.nm_so;
474 struct sockaddr *nam = msg->bind.nm_nam;
478 * in_pcbbind assumes that nam is a sockaddr_in
479 * and in_pcbbind requires a valid address. Since divert
480 * sockets don't we need to make sure the address is
481 * filled in properly.
482 * XXX -- divert should not be abusing in_pcbind
483 * and should probably have its own family.
485 if (nam->sa_family != AF_INET) {
486 error = EAFNOSUPPORT;
488 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
489 error = in_pcbbind(so->so_pcb, nam, msg->bind.nm_td);
491 lwkt_replymsg(&msg->bind.base.lmsg, error);
495 div_shutdown(netmsg_t msg)
497 struct socket *so = msg->shutdown.base.nm_so;
501 lwkt_replymsg(&msg->shutdown.base.lmsg, 0);
505 div_send(netmsg_t msg)
507 struct socket *so = msg->send.base.nm_so;
508 struct mbuf *m = msg->send.nm_m;
509 struct sockaddr *nam = msg->send.nm_addr;
510 struct mbuf *control = msg->send.nm_control;
513 /* Length check already done in ip_cpufn() */
514 KASSERT(m->m_len >= sizeof(struct ip), ("IP header not in one mbuf"));
517 error = div_output(so, m, (struct sockaddr_in *)nam, control);
518 lwkt_replymsg(&msg->send.base.lmsg, error);
521 SYSCTL_DECL(_net_inet_divert);
522 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, &divcbinfo, 0,
523 in_pcblist_global, "S,xinpcb", "List of active divert sockets");
525 struct pr_usrreqs div_usrreqs = {
526 .pru_abort = div_abort,
527 .pru_accept = pr_generic_notsupp,
528 .pru_attach = div_attach,
529 .pru_bind = div_bind,
530 .pru_connect = pr_generic_notsupp,
531 .pru_connect2 = pr_generic_notsupp,
532 .pru_control = in_control_dispatch,
533 .pru_detach = div_detach,
534 .pru_disconnect = div_disconnect,
535 .pru_listen = pr_generic_notsupp,
536 .pru_peeraddr = in_setpeeraddr_dispatch,
537 .pru_rcvd = pr_generic_notsupp,
538 .pru_rcvoob = pr_generic_notsupp,
539 .pru_send = div_send,
540 .pru_sense = pru_sense_null,
541 .pru_shutdown = div_shutdown,
542 .pru_sockaddr = in_setsockaddr_dispatch,
543 .pru_sosend = sosend,
544 .pru_soreceive = soreceive
548 ip_divert_out(struct mbuf *m, int tee)
550 struct mbuf *clone = NULL;
551 struct ip *ip = mtod(m, struct ip *);
553 /* Clone packet if we're doing a 'tee' */
555 clone = m_dup(m, MB_DONTWAIT);
559 * delayed checksums are not currently compatible
560 * with divert sockets.
562 if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
564 m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
567 /* Restore packet header fields to original values */
568 ip->ip_len = htons(ip->ip_len);
569 ip->ip_off = htons(ip->ip_off);
571 /* Deliver packet to divert input routine */
574 /* If 'tee', continue with original packet */
579 ip_divert_in(struct mbuf *m, int tee)
581 struct mbuf *clone = NULL;
582 struct ip *ip = mtod(m, struct ip *);
585 if (ip->ip_off & (IP_MF | IP_OFFMASK)) {
586 const struct divert_info *divinfo;
591 * Only trust divert info in the fragment
594 frag_off = ip->ip_off << 3;
596 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
597 m_tag_delete(m, mtag);
601 * Attempt reassembly; if it succeeds, proceed.
602 * ip_reass() will return a different mbuf.
607 ip = mtod(m, struct ip *);
609 /* Caller need to redispatch the packet, if it is for us */
610 m->m_pkthdr.fw_flags |= FW_MBUF_REDISPATCH;
613 * Get the header length of the reassembled
616 hlen = IP_VHL_HL(ip->ip_vhl) << 2;
619 * Restore original checksum before diverting
623 ip->ip_len = htons(ip->ip_len);
624 ip->ip_off = htons(ip->ip_off);
626 if (hlen == sizeof(struct ip))
627 ip->ip_sum = in_cksum_hdr(ip);
629 ip->ip_sum = in_cksum(m, hlen);
630 ip->ip_off = ntohs(ip->ip_off);
631 ip->ip_len = ntohs(ip->ip_len);
634 * Only use the saved divert info
636 mtag = m_tag_find(m, PACKET_TAG_IPFW_DIVERT, NULL);
638 /* Wrongly configured ipfw */
639 kprintf("ip_input no divert info\n");
643 divinfo = m_tag_data(mtag);
648 * Divert or tee packet to the divert protocol if
652 /* Clone packet if we're doing a 'tee' */
654 clone = m_dup(m, MB_DONTWAIT);
657 * Restore packet header fields to original
660 ip->ip_len = htons(ip->ip_len);
661 ip->ip_off = htons(ip->ip_off);
663 /* Deliver packet to divert input routine */
666 /* Catch invalid reference */
670 ipstat.ips_delivered++;
672 /* If 'tee', continue with original packet */
675 * Complete processing of the packet.
676 * XXX Better safe than sorry, remove the DIVERT tag.
678 mtag = m_tag_find(clone, PACKET_TAG_IPFW_DIVERT, NULL);
679 KKASSERT(mtag != NULL);
680 m_tag_delete(clone, mtag);
686 ip_divert(struct mbuf *m, int tee, int incoming)
691 ret = ip_divert_in(m, tee);
693 ret = ip_divert_out(m, tee);