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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 1.11 2004/03/31 00:43:09 hsu 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/sysctl.h>
54 #include <sys/systm.h>
57 #include <vm/vm_zone.h>
60 #include <net/netisr.h>
61 #include <net/route.h>
63 #include <netinet/in.h>
64 #include <netinet/in_systm.h>
65 #include <netinet/ip.h>
66 #include <netinet/in_pcb.h>
67 #include <netinet/in_var.h>
68 #include <netinet/ip_var.h>
75 * Allocate enough space to hold a full IP packet
77 #define DIVSNDQ (65536 + 100)
78 #define DIVRCVQ (65536 + 100)
81 * Divert sockets work in conjunction with ipfw, see the divert(4)
82 * manpage for features.
83 * Internally, packets selected by ipfw in ip_input() or ip_output(),
84 * and never diverted before, are passed to the input queue of the
85 * divert socket with a given 'divert_port' number (as specified in
86 * the matching ipfw rule), and they are tagged with a 16 bit cookie
87 * (representing the rule number of the matching ipfw rule), which
88 * is passed to process reading from the socket.
90 * Packets written to the divert socket are again tagged with a cookie
91 * (usually the same as above) and a destination address.
92 * If the destination address is INADDR_ANY then the packet is
93 * treated as outgoing and sent to ip_output(), otherwise it is
94 * treated as incoming and sent to ip_input().
95 * In both cases, the packet is tagged with the cookie.
97 * On reinjection, processing in ip_input() and ip_output()
98 * will be exactly the same as for the original packet, except that
99 * ipfw processing will start at the rule number after the one
100 * written in the cookie (so, tagging a packet with a cookie of 0
101 * will cause it to be effectively considered as a standard packet).
104 /* Internal variables */
105 static struct inpcbinfo divcbinfo;
107 static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */
108 static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */
110 /* Optimization: have this preinitialized */
111 static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET };
114 * Initialize divert connection block queue.
119 LIST_INIT(&divcbinfo.listhead);
121 * XXX We don't use the hash list for divert IP, but it's easier
122 * to allocate a one entry hash list than it is to check all
123 * over the place for hashbase == NULL.
125 divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask);
126 divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask);
127 divcbinfo.wildcardhashbase = hashinit(1, M_PCB,
128 &divcbinfo.wildcardhashmask);
129 divcbinfo.ipi_zone = zinit("divcb", sizeof(struct inpcb),
130 maxsockets, ZONE_INTERRUPT, 0);
134 * IPPROTO_DIVERT is not a real IP protocol; don't allow any packets
135 * with that protocol number to enter the system from the outside.
138 div_input(struct mbuf *m, int off, int proto)
140 ipstat.ips_noproto++;
145 * Divert a packet by passing it up to the divert socket at port 'port'.
147 * Setup generic address and protocol structures for div_input routine,
148 * then pass them along with mbuf chain.
151 divert_packet(struct mbuf *m, int incoming, int port, int rule)
159 KASSERT(port != 0, ("%s: port=0", __FUNCTION__));
161 divsrc.sin_port = rule; /* record matching rule */
164 if (m->m_len < sizeof(struct ip) &&
165 (m = m_pullup(m, sizeof(struct ip))) == 0)
167 ip = mtod(m, struct ip *);
170 * Record receive interface address, if any.
171 * But only for incoming packets.
173 divsrc.sin_addr.s_addr = 0;
178 KASSERT((m->m_flags & M_PKTHDR), ("%s: !PKTHDR", __FUNCTION__));
180 /* Find IP address for receive interface */
181 TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
182 if (ifa->ifa_addr == NULL)
184 if (ifa->ifa_addr->sa_family != AF_INET)
187 ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
192 * Record the incoming interface name whenever we have one.
194 bzero(&divsrc.sin_zero, sizeof(divsrc.sin_zero));
195 if (m->m_pkthdr.rcvif) {
197 * Hide the actual interface name in there in the
198 * sin_zero array. XXX This needs to be moved to a
199 * different sockaddr type for divert, e.g.
200 * sockaddr_div with multiple fields like
201 * sockaddr_dl. Presently we have only 7 bytes
202 * but that will do for now as most interfaces
203 * are 4 or less + 2 or less bytes for unit.
204 * There is probably a faster way of doing this,
205 * possibly taking it from the sockaddr_dl on the iface.
206 * This solves the problem of a P2P link and a LAN interface
207 * having the same address, which can result in the wrong
208 * interface being assigned to the packet when fed back
209 * into the divert socket. Theoretically if the daemon saves
210 * and re-uses the sockaddr_in as suggested in the man pages,
211 * this iface name will come along for the ride.
212 * (see div_output for the other half of this.)
214 snprintf(divsrc.sin_zero, sizeof(divsrc.sin_zero),
215 m->m_pkthdr.rcvif->if_xname);
218 /* Put packet on socket queue, if any */
220 nport = htons((u_int16_t)port);
221 LIST_FOREACH(inp, &divcbinfo.listhead, inp_list) {
222 if (inp->inp_lport == nport)
223 sa = inp->inp_socket;
226 if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc,
227 m, (struct mbuf *)0) == 0)
233 ipstat.ips_noproto++;
234 ipstat.ips_delivered--;
239 * Deliver packet back into the IP processing machinery.
241 * If no address specified, or address is 0.0.0.0, send to ip_output();
242 * otherwise, send to ip_input() and mark as having been received on
243 * the interface with that address.
246 div_output(struct socket *so, struct mbuf *m,
247 struct sockaddr_in *sin, struct mbuf *control)
250 struct m_hdr divert_tag;
253 * Prepare the tag for divert info. Note that a packet
254 * with a 0 tag in mh_data is effectively untagged,
255 * so we could optimize that case.
257 divert_tag.mh_type = MT_TAG;
258 divert_tag.mh_flags = PACKET_TAG_DIVERT;
259 divert_tag.mh_next = m;
260 divert_tag.mh_data = 0; /* the matching rule # */
261 m->m_pkthdr.rcvif = NULL; /* XXX is it necessary ? */
264 m_freem(control); /* XXX */
266 /* Loopback avoidance and state recovery */
270 divert_tag.mh_data = (caddr_t)(int)sin->sin_port;
272 * Find receive interface with the given name, stuffed
273 * (if it exists) in the sin_zero[] field.
274 * The name is user supplied data so don't trust its size
275 * or that it is zero terminated.
277 for (i = 0; sin->sin_zero[i] && i < sizeof(sin->sin_zero); i++)
279 if ( i > 0 && i < sizeof(sin->sin_zero))
280 m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
283 /* Reinject packet into the system as incoming or outgoing */
284 if (!sin || sin->sin_addr.s_addr == 0) {
285 struct inpcb *const inp = sotoinpcb(so);
286 struct ip *const ip = mtod(m, struct ip *);
289 * Don't allow both user specified and setsockopt options,
290 * and don't allow packet length sizes that will crash
292 if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) ||
293 ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) {
298 /* Convert fields to host order for ip_output() */
299 ip->ip_len = ntohs(ip->ip_len);
300 ip->ip_off = ntohs(ip->ip_off);
302 /* Send packet to output processing */
303 ipstat.ips_rawout++; /* XXX */
304 error = ip_output((struct mbuf *)&divert_tag,
305 inp->inp_options, &inp->inp_route,
306 (so->so_options & SO_DONTROUTE) |
307 IP_ALLOWBROADCAST | IP_RAWOUTPUT,
308 inp->inp_moptions, NULL);
310 struct netmsg_packet msg;
312 if (m->m_pkthdr.rcvif == NULL) {
314 * No luck with the name, check by IP address.
315 * Clear the port and the ifname to make sure
316 * there are no distractions for ifa_ifwithaddr.
320 bzero(sin->sin_zero, sizeof(sin->sin_zero));
322 ifa = ifa_ifwithaddr((struct sockaddr *) sin);
324 error = EADDRNOTAVAIL;
327 m->m_pkthdr.rcvif = ifa->ifa_ifp;
329 /* Send packet to input processing */
330 msg.nm_packet = (struct mbuf *)&divert_tag;
331 ip_input((struct netmsg *)&msg);
342 div_attach(struct socket *so, int proto, struct pru_attach_info *ai)
350 if ((error = suser_cred(ai->p_ucred, NULL_CRED_OKAY)) != 0)
353 error = soreserve(so, div_sendspace, div_recvspace, ai->sb_rlimit);
357 error = in_pcballoc(so, &divcbinfo);
361 inp = (struct inpcb *)so->so_pcb;
362 inp->inp_ip_p = proto;
363 inp->inp_vflag |= INP_IPV4;
364 inp->inp_flags |= INP_HDRINCL;
365 /* The socket is always "connected" because
366 we always know "where" to send the packet */
367 so->so_state |= SS_ISCONNECTED;
372 div_detach(struct socket *so)
384 div_abort(struct socket *so)
386 soisdisconnected(so);
387 return div_detach(so);
391 div_disconnect(struct socket *so)
393 if ((so->so_state & SS_ISCONNECTED) == 0)
395 return div_abort(so);
399 div_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
407 /* in_pcbbind assumes that nam is a sockaddr_in
408 * and in_pcbbind requires a valid address. Since divert
409 * sockets don't we need to make sure the address is
410 * filled in properly.
411 * XXX -- divert should not be abusing in_pcbind
412 * and should probably have its own family.
414 if (nam->sa_family != AF_INET)
415 error = EAFNOSUPPORT;
417 ((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
418 error = in_pcbbind(inp, nam, td);
425 div_shutdown(struct socket *so)
432 div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
433 struct mbuf *control, struct thread *td)
435 /* Packet must have a header (but that's about it) */
436 if (m->m_len < sizeof (struct ip) &&
437 (m = m_pullup(m, sizeof (struct ip))) == 0) {
438 ipstat.ips_toosmall++;
444 return div_output(so, m, (struct sockaddr_in *)nam, control);
448 div_pcblist(SYSCTL_HANDLER_ARGS)
451 struct inpcb *inp, **inp_list;
456 * The process of preparing the TCB list is too time-consuming and
457 * resource-intensive to repeat twice on every request.
459 if (req->oldptr == 0) {
460 n = divcbinfo.ipi_count;
461 req->oldidx = 2 * (sizeof xig)
462 + (n + n/8) * sizeof(struct xinpcb);
466 if (req->newptr != 0)
470 * OK, now we're committed to doing something.
473 gencnt = divcbinfo.ipi_gencnt;
474 n = divcbinfo.ipi_count;
477 xig.xig_len = sizeof xig;
479 xig.xig_gen = gencnt;
480 xig.xig_sogen = so_gencnt;
481 error = SYSCTL_OUT(req, &xig, sizeof xig);
485 inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
490 for (inp = LIST_FIRST(&divcbinfo.listhead), i = 0; inp && i < n;
491 inp = LIST_NEXT(inp, inp_list)) {
492 if (inp->inp_gencnt <= gencnt && !prison_xinpcb(req->td, inp))
499 for (i = 0; i < n; i++) {
501 if (inp->inp_gencnt <= gencnt) {
503 xi.xi_len = sizeof xi;
504 /* XXX should avoid extra copy */
505 bcopy(inp, &xi.xi_inp, sizeof *inp);
507 sotoxsocket(inp->inp_socket, &xi.xi_socket);
508 error = SYSCTL_OUT(req, &xi, sizeof xi);
513 * Give the user an updated idea of our state.
514 * If the generation differs from what we told
515 * her before, she knows that something happened
516 * while we were processing this request, and it
517 * might be necessary to retry.
520 xig.xig_gen = divcbinfo.ipi_gencnt;
521 xig.xig_sogen = so_gencnt;
522 xig.xig_count = divcbinfo.ipi_count;
524 error = SYSCTL_OUT(req, &xig, sizeof xig);
526 free(inp_list, M_TEMP);
530 SYSCTL_DECL(_net_inet_divert);
531 SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, 0, 0,
532 div_pcblist, "S,xinpcb", "List of active divert sockets");
534 struct pr_usrreqs div_usrreqs = {
535 div_abort, pru_accept_notsupp, div_attach, div_bind,
536 pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach,
537 div_disconnect, pru_listen_notsupp, in_setpeeraddr, pru_rcvd_notsupp,
538 pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown,
539 in_setsockaddr, sosend, soreceive, sopoll