OpenBSD-4.6/sbin/isakmpd/udp_encap.c
/* $OpenBSD: udp_encap.c,v 1.21 2007/04/16 13:01:39 moritz Exp $ */
/*
* Copyright (c) 1998, 1999, 2001 Niklas Hallqvist. All rights reserved.
* Copyright (c) 2000 Angelos D. Keromytis. All rights reserved.
* Copyright (c) 2004 Håkan Olsson. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <ctype.h>
#include <limits.h>
#include <netdb.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "sysdep.h"
#include "conf.h"
#include "if.h"
#include "ipsec_doi.h"
#include "isakmp.h"
#include "log.h"
#include "message.h"
#include "monitor.h"
#include "transport.h"
#include "udp.h"
#include "udp_encap.h"
#include "util.h"
#include "virtual.h"
#define UDP_SIZE 65536
/* If a system doesn't have SO_REUSEPORT, SO_REUSEADDR will have to do. */
#ifndef SO_REUSEPORT
#define SO_REUSEPORT SO_REUSEADDR
#endif
/* Reused, from udp.c */
struct transport *udp_clone(struct transport *, struct sockaddr *);
int udp_fd_set(struct transport *, fd_set *, int);
int udp_fd_isset(struct transport *, fd_set *);
void udp_get_dst(struct transport *, struct sockaddr **);
void udp_get_src(struct transport *, struct sockaddr **);
char *udp_decode_ids(struct transport *);
void udp_remove(struct transport *);
static struct transport *udp_encap_create(char *);
static void udp_encap_report(struct transport *);
static void udp_encap_handle_message(struct transport *);
static struct transport *udp_encap_make(struct sockaddr *);
static int udp_encap_send_message(struct message *,
struct transport *);
static struct transport_vtbl udp_encap_transport_vtbl = {
{ 0 }, "udp_encap",
udp_encap_create,
0,
udp_remove,
udp_encap_report,
udp_fd_set,
udp_fd_isset,
udp_encap_handle_message,
udp_encap_send_message,
udp_get_dst,
udp_get_src,
udp_decode_ids,
udp_clone,
0
};
char *udp_encap_default_port = 0;
void
udp_encap_init(void)
{
transport_method_add(&udp_encap_transport_vtbl);
}
/* Create a UDP transport structure bound to LADDR just for listening. */
static struct transport *
udp_encap_make(struct sockaddr *laddr)
{
struct udp_transport *t = 0;
int s, on, wildcardaddress = 0;
char *tstr;
t = calloc(1, sizeof *t);
if (!t) {
log_print("udp_encap_make: malloc (%lu) failed",
(unsigned long)sizeof *t);
free(laddr);
return 0;
}
t->src = laddr;
s = socket(laddr->sa_family, SOCK_DGRAM, IPPROTO_UDP);
if (s == -1) {
log_error("udp_encap_make: socket (%d, %d, %d)",
laddr->sa_family, SOCK_DGRAM, IPPROTO_UDP);
goto err;
}
/* Make sure we don't get our traffic encrypted. */
if (sysdep_cleartext(s, laddr->sa_family) == -1)
goto err;
/* Wildcard address ? */
switch (laddr->sa_family) {
case AF_INET:
if (((struct sockaddr_in *)laddr)->sin_addr.s_addr
== INADDR_ANY)
wildcardaddress = 1;
break;
case AF_INET6:
if (IN6_IS_ADDR_UNSPECIFIED(&((struct sockaddr_in6 *)laddr)->sin6_addr))
wildcardaddress = 1;
break;
}
/*
* In order to have several bound specific address-port combinations
* with the same port SO_REUSEADDR is needed.
* If this is a wildcard socket and we are not listening there, but
* only sending from it make sure it is entirely reuseable with
* SO_REUSEPORT.
*/
on = 1;
if (setsockopt(s, SOL_SOCKET,
wildcardaddress ? SO_REUSEPORT : SO_REUSEADDR,
(void *)&on, sizeof on) == -1) {
log_error("udp_encap_make: setsockopt (%d, %d, %d, %p, %lu)",
s, SOL_SOCKET,
wildcardaddress ? SO_REUSEPORT : SO_REUSEADDR, &on,
(unsigned long)sizeof on);
goto err;
}
t->transport.vtbl = &udp_encap_transport_vtbl;
if (monitor_bind(s, t->src, SA_LEN(t->src))) {
if (sockaddr2text(t->src, &tstr, 0))
log_error("udp_encap_make: bind (%d, %p, %lu)", s,
&t->src, (unsigned long)sizeof t->src);
else {
log_error("udp_encap_make: bind (%d, %s, %lu)", s,
tstr, (unsigned long)sizeof t->src);
free(tstr);
}
goto err;
}
t->s = s;
if (sockaddr2text(t->src, &tstr, 0))
LOG_DBG((LOG_MISC, 20, "udp_encap_make: "
"transport %p socket %d family %d", t, s,
t->src->sa_family == AF_INET ? 4 : 6));
else {
LOG_DBG((LOG_MISC, 20, "udp_encap_make: "
"transport %p socket %d ip %s port %d", t, s,
tstr, ntohs(sockaddr_port(t->src))));
free(tstr);
}
transport_setup(&t->transport, 0);
t->transport.flags |= TRANSPORT_LISTEN;
return &t->transport;
err:
if (s >= 0)
close (s);
if (t) {
/* Already closed. */
t->s = -1;
udp_remove(&t->transport);
}
return 0;
}
/*
* Initialize an object of the UDP transport class. Fill in the local
* IP address and port information and create a server socket bound to
* that specific port. Add the polymorphic transport structure to the
* system-wide pools of known ISAKMP transports.
*/
struct transport *
udp_encap_bind(const struct sockaddr *addr)
{
struct sockaddr *src;
src = malloc(SA_LEN(addr));
if (!src)
return 0;
memcpy(src, addr, SA_LEN(addr));
return udp_encap_make(src);
}
/*
* NAME is a section name found in the config database. Setup and return
* a transport useable to talk to the peer specified by that name.
*/
static struct transport *
udp_encap_create(char *name)
{
struct virtual_transport *v;
struct udp_transport *u;
struct transport *rv, *t;
struct sockaddr *dst, *addr;
struct conf_list *addr_list = 0;
struct conf_list_node *addr_node;
char *addr_str, *port_str;
port_str = conf_get_str(name, "Port"); /* XXX "Encap-port" ? */
if (!port_str)
port_str = udp_encap_default_port;
if (!port_str)
port_str = UDP_ENCAP_DEFAULT_PORT_STR;
addr_str = conf_get_str(name, "Address");
if (!addr_str) {
log_print("udp_encap_create: no address configured "
"for \"%s\"", name);
return 0;
}
if (text2sockaddr(addr_str, port_str, &dst, 0, 0)) {
log_print("udp_encap_create: address \"%s\" not understood",
addr_str);
return 0;
}
addr_str = conf_get_str(name, "Local-address");
if (!addr_str)
addr_list = conf_get_list("General", "Listen-on");
if (!addr_str && !addr_list) {
v = virtual_get_default(dst->sa_family);
u = (struct udp_transport *)v->encap;
if (!u) {
log_print("udp_encap_create: no default transport");
rv = 0;
goto ret;
} else {
rv = udp_clone((struct transport *)u, dst);
if (rv)
rv->vtbl = &udp_encap_transport_vtbl;
goto ret;
}
}
if (addr_list) {
for (addr_node = TAILQ_FIRST(&addr_list->fields);
addr_node; addr_node = TAILQ_NEXT(addr_node, link))
if (text2sockaddr(addr_node->field, port_str,
&addr, 0, 0) == 0) {
v = virtual_listen_lookup(addr);
free(addr);
if (v) {
addr_str = addr_node->field;
break;
}
}
if (!addr_str) {
log_print("udp_encap_create: "
"no matching listener found");
rv = 0;
goto ret;
}
}
if (text2sockaddr(addr_str, port_str, &addr, 0, 0)) {
log_print("udp_encap_create: "
"address \"%s\" not understood", addr_str);
rv = 0;
goto ret;
}
v = virtual_listen_lookup(addr);
free(addr);
if (!v) {
log_print("udp_encap_create: "
"%s:%s must exist as a listener too", addr_str, port_str);
rv = 0;
goto ret;
}
t = (struct transport *)v;
rv = udp_clone(v->encap, dst);
if (rv)
rv->vtbl = &udp_encap_transport_vtbl;
ret:
if (addr_list)
conf_free_list(addr_list);
free(dst);
return rv;
}
/* Report transport-method specifics of the T transport. */
void
udp_encap_report(struct transport *t)
{
struct udp_transport *u = (struct udp_transport *)t;
char *src = NULL, *dst = NULL;
in_port_t sport, dport;
if (sockaddr2text(u->src, &src, 0))
return;
sport = sockaddr_port(u->src);
if (!u->dst || sockaddr2text(u->dst, &dst, 0))
dst = 0;
dport = dst ? sockaddr_port(u->dst) : 0;
LOG_DBG ((LOG_REPORT, 0, "udp_encap_report: fd %d src %s:%u dst %s:%u",
u->s, src, ntohs(sport), dst ? dst : "*", ntohs(dport)));
free(dst);
free(src);
}
/*
* A message has arrived on transport T's socket. If T is single-ended,
* clone it into a double-ended transport which we will use from now on.
* Package the message as we want it and continue processing in the message
* module.
*/
static void
udp_encap_handle_message(struct transport *t)
{
struct udp_transport *u = (struct udp_transport *)t;
struct sockaddr_storage from;
struct message *msg;
u_int32_t len = sizeof from;
ssize_t n;
u_int8_t buf[UDP_SIZE];
n = recvfrom(u->s, buf, UDP_SIZE, 0, (struct sockaddr *)&from, &len);
if (n == -1) {
log_error("recvfrom (%d, %p, %d, %d, %p, %p)", u->s, buf,
UDP_SIZE, 0, &from, &len);
return;
}
if (t->virtual == (struct transport *)virtual_get_default(AF_INET) ||
t->virtual == (struct transport *)virtual_get_default(AF_INET6)) {
t->virtual->vtbl->reinit();
/*
* As we don't know the actual destination address of the
* packet, we can't really deal with it. So, just ignore it
* and hope we catch the retransmission.
*/
return;
}
/*
* Make a specialized UDP transport structure out of the incoming
* transport and the address information we got from recvfrom(2).
*/
t = t->virtual->vtbl->clone(t->virtual, (struct sockaddr *)&from);
if (!t)
return;
/* Check NULL-ESP marker. */
if (n < (ssize_t)sizeof(u_int32_t) || *(u_int32_t *)buf != 0) {
/* Should never happen. */
log_print("udp_encap_handle_message: "
"Null-ESP marker not NULL or short message");
return;
}
/* NAT-Keepalive messages should not be processed further. */
n -= sizeof(u_int32_t);
if (n == 1 && buf[sizeof(u_int32_t)] == 0xFF)
return;
msg = message_alloc(t, buf + sizeof (u_int32_t), n);
if (!msg) {
log_error("failed to allocate message structure, dropping "
"packet received on transport %p", u);
return;
}
msg->flags |= MSG_NATT;
message_recv(msg);
}
/*
* Physically send the message MSG over its associated transport.
* Special: if 'msg' is NULL, send a NAT-T keepalive message.
*/
static int
udp_encap_send_message(struct message *msg, struct transport *t)
{
struct udp_transport *u = (struct udp_transport *)t;
struct msghdr m;
struct iovec *new_iov = 0, keepalive;
ssize_t n;
u_int32_t marker = 0; /* NULL-ESP Marker */
if (msg) {
/* Construct new iov array, prefixing NULL-ESP Marker. */
new_iov = (struct iovec *)calloc (msg->iovlen + 1,
sizeof *new_iov);
if (!new_iov) {
log_error ("udp_encap_send_message: "
"calloc (%lu, %lu) failed",
(unsigned long)msg->iovlen + 1,
(unsigned long)sizeof *new_iov);
return -1;
}
new_iov[0].iov_base = ▮
new_iov[0].iov_len = IPSEC_SPI_SIZE;
memcpy (new_iov + 1, msg->iov, msg->iovlen * sizeof *new_iov);
} else {
marker = ~marker;
keepalive.iov_base = ▮
keepalive.iov_len = 1;
}
/*
* Sending on connected sockets requires that no destination address is
* given, or else EISCONN will occur.
*/
m.msg_name = (caddr_t)u->dst;
m.msg_namelen = SA_LEN(u->dst);
m.msg_iov = msg ? new_iov : &keepalive;
m.msg_iovlen = msg ? msg->iovlen + 1 : 1;
m.msg_control = 0;
m.msg_controllen = 0;
m.msg_flags = 0;
n = sendmsg (u->s, &m, 0);
if (msg)
free (new_iov);
if (n == -1) {
/* XXX We should check whether the address has gone away */
log_error ("sendmsg (%d, %p, %d)", u->s, &m, 0);
return -1;
}
return 0;
}