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freebsd/sys/netinet/ip_divert.c
Yoshinobu Inoue 0ba9128b0c prevent kernel panic which happens when either of IPSEC and IPDIVERT
is enabled.

Confirmed by: Eugene M. Kim <ab@astralblue.com>
2000-01-08 12:53:48 +00:00

444 lines
12 KiB
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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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.
*
* $FreeBSD$
*/
#include "opt_inet.h"
#include "opt_ipfw.h"
#include "opt_ipdivert.h"
#include "opt_ipsec.h"
#ifndef INET
#error "IPDIVERT requires INET."
#endif
#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/protosw.h>
#include <sys/socketvar.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <vm/vm_zone.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.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)
/*
* A 16 bit cookie is passed to and from the user process.
* The user process can send it back to help the caller know
* something about where the packet originally came from.
*
* In the case of ipfw, then the cookie is the rule that sent
* us here. On reinjection is is the rule after which processing
* should continue. Leaving it the same will make processing start
* at the rule number after that which sent it here. Setting it to
* 0 will restart processing at the beginning.
*
* For divert_packet(), ip_divert_cookie is an input value only.
* For div_output(), ip_divert_cookie is an output value only.
*/
u_int16_t ip_divert_cookie;
/* 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 ? */
/* Optimization: have this preinitialized */
static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET };
/* Internal functions */
static int div_output(struct socket *so,
struct mbuf *m, struct sockaddr *addr, struct mbuf *control);
/*
* Initialize divert connection block queue.
*/
void
div_init(void)
{
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 = zinit("divcb", sizeof(struct inpcb),
maxsockets, ZONE_INTERRUPT, 0);
}
/*
* IPPROTO_DIVERT is not a real IP protocol; don't allow any packets
* with that protocol number to enter the system from the outside.
*/
void
div_input(struct mbuf *m, int off, int proto)
{
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, int port)
{
struct ip *ip;
struct inpcb *inp;
struct socket *sa;
u_int16_t nport;
/* Sanity check */
KASSERT(port != 0, ("%s: port=0", __FUNCTION__));
/* Record and reset divert cookie */
divsrc.sin_port = ip_divert_cookie;
ip_divert_cookie = 0;
/* Assure header */
if (m->m_len < sizeof(struct ip) &&
(m = m_pullup(m, sizeof(struct ip))) == 0) {
return;
}
ip = mtod(m, struct ip *);
/*
* Record receive interface address, if any.
* But only for incoming packets.
*/
divsrc.sin_addr.s_addr = 0;
if (incoming) {
struct ifaddr *ifa;
/* Sanity check */
KASSERT((m->m_flags & M_PKTHDR), ("%s: !PKTHDR", __FUNCTION__));
/* Find IP address for receive interface */
for (ifa = m->m_pkthdr.rcvif->if_addrhead.tqh_first;
ifa != NULL; ifa = ifa->ifa_link.tqe_next) {
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.
*/
bzero(&divsrc.sin_zero, sizeof(divsrc.sin_zero));
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.)
*/
snprintf(divsrc.sin_zero, sizeof(divsrc.sin_zero),
"%s%d", m->m_pkthdr.rcvif->if_name,
m->m_pkthdr.rcvif->if_unit);
}
/* Put packet on socket queue, if any */
sa = NULL;
nport = htons((u_int16_t)port);
for (inp = divcb.lh_first; inp != NULL; inp = inp->inp_list.le_next) {
if (inp->inp_lport == nport)
sa = inp->inp_socket;
}
if (sa) {
if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc,
m, (struct mbuf *)0) == 0)
m_freem(m);
else
sorwakeup(sa);
} else {
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(so, m, addr, control)
struct socket *so;
register struct mbuf *m;
struct sockaddr *addr;
struct mbuf *control;
{
register struct inpcb *const inp = sotoinpcb(so);
register struct ip *const ip = mtod(m, struct ip *);
struct sockaddr_in *sin = (struct sockaddr_in *)addr;
int error = 0;
if (control)
m_freem(control); /* XXX */
/* Loopback avoidance and state recovery */
if (sin) {
int len = 0;
char *c = sin->sin_zero;
ip_divert_cookie = sin->sin_port;
/*
* Find receive interface with the given name or IP address.
* The name is user supplied data so don't trust it's size or
* that it is zero terminated. The name has priority.
* We are presently assuming that the sockaddr_in
* has not been replaced by a sockaddr_div, so we limit it
* to 16 bytes in total. the name is stuffed (if it exists)
* in the sin_zero[] field.
*/
while (*c++ && (len++ < sizeof(sin->sin_zero)));
if ((len > 0) && (len < sizeof(sin->sin_zero)))
m->m_pkthdr.rcvif = ifunit(sin->sin_zero);
} else {
ip_divert_cookie = 0;
}
/* Reinject packet into the system as incoming or outgoing */
if (!sin || sin->sin_addr.s_addr == 0) {
/*
* 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;
goto cantsend;
}
/* Convert fields to host order for ip_output() */
NTOHS(ip->ip_len);
NTOHS(ip->ip_off);
/* Send packet to output processing */
ipstat.ips_rawout++; /* XXX */
error = ip_output(m, inp->inp_options, &inp->inp_route,
(so->so_options & SO_DONTROUTE) |
IP_ALLOWBROADCAST | IP_RAWOUTPUT,
inp->inp_moptions);
} else {
struct ifaddr *ifa;
/* If no luck with the name above. check by IP address. */
if (m->m_pkthdr.rcvif == NULL) {
/*
* Make sure there are no distractions
* for ifa_ifwithaddr. Clear the port and the ifname.
* Maybe zap all 8 bytes at once using a 64bit write?
*/
bzero(sin->sin_zero, sizeof(sin->sin_zero));
/* *((u_int64_t *)sin->sin_zero) = 0; */ /* XXX ?? */
sin->sin_port = 0;
if (!(ifa = ifa_ifwithaddr((struct sockaddr *) sin))) {
error = EADDRNOTAVAIL;
goto cantsend;
}
m->m_pkthdr.rcvif = ifa->ifa_ifp;
}
/* Send packet to input processing */
ip_input(m);
}
/* paranoid: Reset for next time (and other packets) */
/* almost definitly already done in the ipfw filter but.. */
ip_divert_cookie = 0;
return error;
cantsend:
m_freem(m);
ip_divert_cookie = 0;
return error;
}
static int
div_attach(struct socket *so, int proto, struct proc *p)
{
struct inpcb *inp;
int error, s;
inp = sotoinpcb(so);
if (inp)
panic("div_attach");
if (p && (error = suser(p)) != 0)
return error;
error = soreserve(so, div_sendspace, div_recvspace);
if (error)
return error;
s = splnet();
error = in_pcballoc(so, &divcbinfo, p);
splx(s);
if (error)
return error;
inp = (struct inpcb *)so->so_pcb;
inp->inp_ip_p = proto;
inp->inp_flags |= INP_HDRINCL;
/* The socket is always "connected" because
we always know "where" to send the packet */
so->so_state |= SS_ISCONNECTED;
#ifdef IPSEC
error = ipsec_init_policy(so, &inp->inp_sp);
if (error != 0) {
in_pcbdetach(inp);
return error;
}
#endif /*IPSEC*/
return 0;
}
static int
div_detach(struct socket *so)
{
struct inpcb *inp;
inp = sotoinpcb(so);
if (inp == 0)
panic("div_detach");
in_pcbdetach(inp);
return 0;
}
static int
div_abort(struct socket *so)
{
soisdisconnected(so);
return div_detach(so);
}
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 proc *p)
{
struct inpcb *inp;
int s;
int error;
s = splnet();
inp = sotoinpcb(so);
error = in_pcbbind(inp, nam, p);
splx(s);
return 0;
}
static int
div_shutdown(struct socket *so)
{
socantsendmore(so);
return 0;
}
static int
div_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
struct mbuf *control, struct proc *p)
{
/* 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, nam, control);
}
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, in_setpeeraddr, pru_rcvd_notsupp,
pru_rcvoob_notsupp, div_send, pru_sense_null, div_shutdown,
in_setsockaddr, sosend, soreceive, sopoll
};