FreeBSD-5.3/sys/netinet/ip_divert.c
/*
* Copyright (c) 1982, 1986, 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD: src/sys/netinet/ip_divert.c,v 1.98 2004/08/17 22:05:54 andre Exp $
*/
#include "opt_inet.h"
#include "opt_ipfw.h"
#include "opt_ipdivert.h"
#include "opt_ipsec.h"
#include "opt_mac.h"
#ifndef INET
#error "IPDIVERT requires INET."
#endif
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mac.h>
#include <sys/mbuf.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/signalvar.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <vm/uma.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_divert.h>
#include <netinet/ip_var.h>
/*
* Divert sockets
*/
/*
* Allocate enough space to hold a full IP packet
*/
#define DIVSNDQ (65536 + 100)
#define DIVRCVQ (65536 + 100)
/*
* Divert sockets work in conjunction with ipfw, see the divert(4)
* manpage for features.
* Internally, packets selected by ipfw in ip_input() or ip_output(),
* and never diverted before, are passed to the input queue of the
* divert socket with a given 'divert_port' number (as specified in
* the matching ipfw rule), and they are tagged with a 16 bit cookie
* (representing the rule number of the matching ipfw rule), which
* is passed to process reading from the socket.
*
* Packets written to the divert socket are again tagged with a cookie
* (usually the same as above) and a destination address.
* If the destination address is INADDR_ANY then the packet is
* treated as outgoing and sent to ip_output(), otherwise it is
* treated as incoming and sent to ip_input().
* In both cases, the packet is tagged with the cookie.
*
* On reinjection, processing in ip_input() and ip_output()
* will be exactly the same as for the original packet, except that
* ipfw processing will start at the rule number after the one
* written in the cookie (so, tagging a packet with a cookie of 0
* will cause it to be effectively considered as a standard packet).
*/
/* Internal variables */
static struct inpcbhead divcb;
static struct inpcbinfo divcbinfo;
static u_long div_sendspace = DIVSNDQ; /* XXX sysctl ? */
static u_long div_recvspace = DIVRCVQ; /* XXX sysctl ? */
/*
* Initialize divert connection block queue.
*/
void
div_init(void)
{
INP_INFO_LOCK_INIT(&divcbinfo, "div");
LIST_INIT(&divcb);
divcbinfo.listhead = &divcb;
/*
* XXX We don't use the hash list for divert IP, but it's easier
* to allocate a one entry hash list than it is to check all
* over the place for hashbase == NULL.
*/
divcbinfo.hashbase = hashinit(1, M_PCB, &divcbinfo.hashmask);
divcbinfo.porthashbase = hashinit(1, M_PCB, &divcbinfo.porthashmask);
divcbinfo.ipi_zone = uma_zcreate("divcb", sizeof(struct inpcb),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
uma_zone_set_max(divcbinfo.ipi_zone, maxsockets);
}
/*
* IPPROTO_DIVERT is not in the real IP protocol number space; this
* function should never be called. Just in case, drop any packets.
*/
void
div_input(struct mbuf *m, int off)
{
ipstat.ips_noproto++;
m_freem(m);
}
/*
* Divert a packet by passing it up to the divert socket at port 'port'.
*
* Setup generic address and protocol structures for div_input routine,
* then pass them along with mbuf chain.
*/
void
divert_packet(struct mbuf *m, int incoming)
{
struct ip *ip;
struct inpcb *inp;
struct socket *sa;
u_int16_t nport;
struct sockaddr_in divsrc;
struct m_tag *mtag;
mtag = m_tag_find(m, PACKET_TAG_DIVERT, NULL);
if (mtag == NULL) {
printf("%s: no divert tag\n", __func__);
m_freem(m);
return;
}
/* Assure header */
if (m->m_len < sizeof(struct ip) &&
(m = m_pullup(m, sizeof(struct ip))) == 0)
return;
ip = mtod(m, struct ip *);
/* Delayed checksums are currently not compatible with divert. */
if (m->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
ip->ip_len = ntohs(ip->ip_len);
in_delayed_cksum(m);
m->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
ip->ip_len = htons(ip->ip_len);
}
/*
* Record receive interface address, if any.
* But only for incoming packets.
*/
bzero(&divsrc, sizeof(divsrc));
divsrc.sin_len = sizeof(divsrc);
divsrc.sin_family = AF_INET;
divsrc.sin_port = divert_cookie(mtag); /* record matching rule */
if (incoming) {
struct ifaddr *ifa;
/* Sanity check */
M_ASSERTPKTHDR(m);
/* Find IP address for receive interface */
TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrhead, ifa_link) {
if (ifa->ifa_addr == NULL)
continue;
if (ifa->ifa_addr->sa_family != AF_INET)
continue;
divsrc.sin_addr =
((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
break;
}
}
/*
* Record the incoming interface name whenever we have one.
*/
if (m->m_pkthdr.rcvif) {
/*
* Hide the actual interface name in there in the
* sin_zero array. XXX This needs to be moved to a
* different sockaddr type for divert, e.g.
* sockaddr_div with multiple fields like
* sockaddr_dl. Presently we have only 7 bytes
* but that will do for now as most interfaces
* are 4 or less + 2 or less bytes for unit.
* There is probably a faster way of doing this,
* possibly taking it from the sockaddr_dl on the iface.
* This solves the problem of a P2P link and a LAN interface
* having the same address, which can result in the wrong
* interface being assigned to the packet when fed back
* into the divert socket. Theoretically if the daemon saves
* and re-uses the sockaddr_in as suggested in the man pages,
* this iface name will come along for the ride.
* (see div_output for the other half of this.)
*/
strlcpy(divsrc.sin_zero, m->m_pkthdr.rcvif->if_xname,
sizeof(divsrc.sin_zero));
}
/* Put packet on socket queue, if any */
sa = NULL;
nport = htons((u_int16_t)divert_info(mtag));
INP_INFO_RLOCK(&divcbinfo);
LIST_FOREACH(inp, &divcb, inp_list) {
INP_LOCK(inp);
/* XXX why does only one socket match? */
if (inp->inp_lport == nport) {
sa = inp->inp_socket;
SOCKBUF_LOCK(&sa->so_rcv);
if (sbappendaddr_locked(&sa->so_rcv,
(struct sockaddr *)&divsrc, m,
(struct mbuf *)0) == 0) {
SOCKBUF_UNLOCK(&sa->so_rcv);
sa = NULL; /* force mbuf reclaim below */
} else
sorwakeup_locked(sa);
INP_UNLOCK(inp);
break;
}
INP_UNLOCK(inp);
}
INP_INFO_RUNLOCK(&divcbinfo);
if (sa == NULL) {
m_freem(m);
ipstat.ips_noproto++;
ipstat.ips_delivered--;
}
}
/*
* Deliver packet back into the IP processing machinery.
*
* If no address specified, or address is 0.0.0.0, send to ip_output();
* otherwise, send to ip_input() and mark as having been received on
* the interface with that address.
*/
static int
div_output(struct socket *so, struct mbuf *m,
struct sockaddr_in *sin, struct mbuf *control)
{
int error = 0;
KASSERT(m->m_pkthdr.rcvif == NULL, ("rcvif not null"));
if (control)
m_freem(control); /* XXX */
/* Loopback avoidance and state recovery */
if (sin) {
struct m_tag *mtag;
struct divert_tag *dt;
int i;
mtag = m_tag_get(PACKET_TAG_DIVERT,
sizeof(struct divert_tag), M_NOWAIT);
if (mtag == NULL) {
error = ENOBUFS;
goto cantsend;
}
dt = (struct divert_tag *)(mtag+1);
dt->info = 0;
dt->cookie = sin->sin_port;
m_tag_prepend(m, mtag);
/*
* Find receive interface with the given name, stuffed
* (if it exists) in the sin_zero[] field.
* The name is user supplied data so don't trust its size
* or that it is zero terminated.
*/
for (i = 0; i < sizeof(sin->sin_zero) && sin->sin_zero[i]; i++)
;
if ( i > 0 && i < sizeof(sin->sin_zero))
m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
}
/* Reinject packet into the system as incoming or outgoing */
if (!sin || sin->sin_addr.s_addr == 0) {
struct ip *const ip = mtod(m, struct ip *);
struct inpcb *inp;
INP_INFO_WLOCK(&divcbinfo);
inp = sotoinpcb(so);
INP_LOCK(inp);
/*
* Don't allow both user specified and setsockopt options,
* and don't allow packet length sizes that will crash
*/
if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) ||
((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) {
error = EINVAL;
m_freem(m);
} else {
/* Convert fields to host order for ip_output() */
ip->ip_len = ntohs(ip->ip_len);
ip->ip_off = ntohs(ip->ip_off);
/* Send packet to output processing */
ipstat.ips_rawout++; /* XXX */
#ifdef MAC
mac_create_mbuf_from_inpcb(inp, m);
#endif
error = ip_output(m,
inp->inp_options, NULL,
(so->so_options & SO_DONTROUTE) |
IP_ALLOWBROADCAST | IP_RAWOUTPUT,
inp->inp_moptions, NULL);
}
INP_UNLOCK(inp);
INP_INFO_WUNLOCK(&divcbinfo);
} else {
if (m->m_pkthdr.rcvif == NULL) {
/*
* No luck with the name, check by IP address.
* Clear the port and the ifname to make sure
* there are no distractions for ifa_ifwithaddr.
*/
struct ifaddr *ifa;
bzero(sin->sin_zero, sizeof(sin->sin_zero));
sin->sin_port = 0;
ifa = ifa_ifwithaddr((struct sockaddr *) sin);
if (ifa == NULL) {
error = EADDRNOTAVAIL;
goto cantsend;
}
m->m_pkthdr.rcvif = ifa->ifa_ifp;
}
#ifdef MAC
SOCK_LOCK(so);
mac_create_mbuf_from_socket(so, m);
SOCK_UNLOCK(so);
#endif
/* Send packet to input processing */
ip_input(m);
}
return error;
cantsend:
m_freem(m);
return error;
}
static int
div_attach(struct socket *so, int proto, struct thread *td)
{
struct inpcb *inp;
int error;
INP_INFO_WLOCK(&divcbinfo);
inp = sotoinpcb(so);
if (inp != 0) {
INP_INFO_WUNLOCK(&divcbinfo);
return EINVAL;
}
if (td && (error = suser(td)) != 0) {
INP_INFO_WUNLOCK(&divcbinfo);
return error;
}
error = soreserve(so, div_sendspace, div_recvspace);
if (error) {
INP_INFO_WUNLOCK(&divcbinfo);
return error;
}
error = in_pcballoc(so, &divcbinfo, "divinp");
if (error) {
INP_INFO_WUNLOCK(&divcbinfo);
return error;
}
inp = (struct inpcb *)so->so_pcb;
INP_LOCK(inp);
INP_INFO_WUNLOCK(&divcbinfo);
inp->inp_ip_p = proto;
inp->inp_vflag |= INP_IPV4;
inp->inp_flags |= INP_HDRINCL;
/* The socket is always "connected" because
we always know "where" to send the packet */
INP_UNLOCK(inp);
SOCK_LOCK(so);
so->so_state |= SS_ISCONNECTED;
SOCK_UNLOCK(so);
return 0;
}
static int
div_detach(struct socket *so)
{
struct inpcb *inp;
INP_INFO_WLOCK(&divcbinfo);
inp = sotoinpcb(so);
if (inp == 0) {
INP_INFO_WUNLOCK(&divcbinfo);
return EINVAL;
}
INP_LOCK(inp);
in_pcbdetach(inp);
INP_INFO_WUNLOCK(&divcbinfo);
return 0;
}
static int
div_abort(struct socket *so)
{
struct inpcb *inp;
INP_INFO_WLOCK(&divcbinfo);
inp = sotoinpcb(so);
if (inp == 0) {
INP_INFO_WUNLOCK(&divcbinfo);
return EINVAL; /* ??? possible? panic instead? */
}
INP_LOCK(inp);
soisdisconnected(so);
in_pcbdetach(inp);
INP_INFO_WUNLOCK(&divcbinfo);
return 0;
}
static int
div_disconnect(struct socket *so)
{
if ((so->so_state & SS_ISCONNECTED) == 0)
return ENOTCONN;
return div_abort(so);
}
static int
div_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
{
struct inpcb *inp;
int error;
INP_INFO_WLOCK(&divcbinfo);
inp = sotoinpcb(so);
if (inp == 0) {
INP_INFO_WUNLOCK(&divcbinfo);
return EINVAL;
}
/* in_pcbbind assumes that nam is a sockaddr_in
* and in_pcbbind requires a valid address. Since divert
* sockets don't we need to make sure the address is
* filled in properly.
* XXX -- divert should not be abusing in_pcbind
* and should probably have its own family.
*/
if (nam->sa_family != AF_INET)
error = EAFNOSUPPORT;
else {
((struct sockaddr_in *)nam)->sin_addr.s_addr = INADDR_ANY;
INP_LOCK(inp);
error = in_pcbbind(inp, nam, td->td_ucred);
INP_UNLOCK(inp);
}
INP_INFO_WUNLOCK(&divcbinfo);
return error;
}
static int
div_shutdown(struct socket *so)
{
struct inpcb *inp;
INP_INFO_RLOCK(&divcbinfo);
inp = sotoinpcb(so);
if (inp == 0) {
INP_INFO_RUNLOCK(&divcbinfo);
return EINVAL;
}
INP_LOCK(inp);
INP_INFO_RUNLOCK(&divcbinfo);
socantsendmore(so);
INP_UNLOCK(inp);
return 0;
}
static int
div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
struct mbuf *control, struct thread *td)
{
/* Packet must have a header (but that's about it) */
if (m->m_len < sizeof (struct ip) &&
(m = m_pullup(m, sizeof (struct ip))) == 0) {
ipstat.ips_toosmall++;
m_freem(m);
return EINVAL;
}
/* Send packet */
return div_output(so, m, (struct sockaddr_in *)nam, control);
}
void
div_ctlinput(int cmd, struct sockaddr *sa, void *vip)
{
struct in_addr faddr;
faddr = ((struct sockaddr_in *)sa)->sin_addr;
if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
return;
if (PRC_IS_REDIRECT(cmd))
return;
}
static int
div_pcblist(SYSCTL_HANDLER_ARGS)
{
int error, i, n;
struct inpcb *inp, **inp_list;
inp_gen_t gencnt;
struct xinpgen xig;
/*
* The process of preparing the TCB list is too time-consuming and
* resource-intensive to repeat twice on every request.
*/
if (req->oldptr == 0) {
n = divcbinfo.ipi_count;
req->oldidx = 2 * (sizeof xig)
+ (n + n/8) * sizeof(struct xinpcb);
return 0;
}
if (req->newptr != 0)
return EPERM;
/*
* OK, now we're committed to doing something.
*/
INP_INFO_RLOCK(&divcbinfo);
gencnt = divcbinfo.ipi_gencnt;
n = divcbinfo.ipi_count;
INP_INFO_RUNLOCK(&divcbinfo);
error = sysctl_wire_old_buffer(req,
2 * sizeof(xig) + n*sizeof(struct xinpcb));
if (error != 0)
return (error);
xig.xig_len = sizeof xig;
xig.xig_count = n;
xig.xig_gen = gencnt;
xig.xig_sogen = so_gencnt;
error = SYSCTL_OUT(req, &xig, sizeof xig);
if (error)
return error;
inp_list = malloc(n * sizeof *inp_list, M_TEMP, M_WAITOK);
if (inp_list == 0)
return ENOMEM;
INP_INFO_RLOCK(&divcbinfo);
for (inp = LIST_FIRST(divcbinfo.listhead), i = 0; inp && i < n;
inp = LIST_NEXT(inp, inp_list)) {
INP_LOCK(inp);
if (inp->inp_gencnt <= gencnt &&
cr_canseesocket(req->td->td_ucred, inp->inp_socket) == 0)
inp_list[i++] = inp;
INP_UNLOCK(inp);
}
INP_INFO_RUNLOCK(&divcbinfo);
n = i;
error = 0;
for (i = 0; i < n; i++) {
inp = inp_list[i];
if (inp->inp_gencnt <= gencnt) {
struct xinpcb xi;
xi.xi_len = sizeof xi;
/* XXX should avoid extra copy */
bcopy(inp, &xi.xi_inp, sizeof *inp);
if (inp->inp_socket)
sotoxsocket(inp->inp_socket, &xi.xi_socket);
error = SYSCTL_OUT(req, &xi, sizeof xi);
}
}
if (!error) {
/*
* Give the user an updated idea of our state.
* If the generation differs from what we told
* her before, she knows that something happened
* while we were processing this request, and it
* might be necessary to retry.
*/
INP_INFO_RLOCK(&divcbinfo);
xig.xig_gen = divcbinfo.ipi_gencnt;
xig.xig_sogen = so_gencnt;
xig.xig_count = divcbinfo.ipi_count;
INP_INFO_RUNLOCK(&divcbinfo);
error = SYSCTL_OUT(req, &xig, sizeof xig);
}
free(inp_list, M_TEMP);
return error;
}
/*
* This is the wrapper function for in_setsockaddr. We just pass down
* the pcbinfo for in_setpeeraddr to lock.
*/
static int
div_sockaddr(struct socket *so, struct sockaddr **nam)
{
return (in_setsockaddr(so, nam, &divcbinfo));
}
/*
* This is the wrapper function for in_setpeeraddr. We just pass down
* the pcbinfo for in_setpeeraddr to lock.
*/
static int
div_peeraddr(struct socket *so, struct sockaddr **nam)
{
return (in_setpeeraddr(so, nam, &divcbinfo));
}
SYSCTL_DECL(_net_inet_divert);
SYSCTL_PROC(_net_inet_divert, OID_AUTO, pcblist, CTLFLAG_RD, 0, 0,
div_pcblist, "S,xinpcb", "List of active divert sockets");
struct pr_usrreqs div_usrreqs = {
div_abort, pru_accept_notsupp, div_attach, div_bind,
pru_connect_notsupp, pru_connect2_notsupp, in_control, div_detach,
div_disconnect, pru_listen_notsupp, div_peeraddr, pru_rcvd_notsupp,
pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown,
div_sockaddr, sosend, soreceive, sopoll, in_pcbsosetlabel
};