283 lines
6.2 KiB
C
283 lines
6.2 KiB
C
/*
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* Copyright (c) 2005 Reyk Floeter <reyk@openbsd.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "includes.h"
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#include <sys/types.h>
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#include <sys/ioctl.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <netinet/ip.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdarg.h>
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#include <string.h>
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#include <unistd.h>
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#include "openbsd-compat/sys-queue.h"
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#include "log.h"
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#include "misc.h"
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#include "sshbuf.h"
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#include "channels.h"
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#include "ssherr.h"
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/*
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* This is the portable version of the SSH tunnel forwarding, it
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* uses some preprocessor definitions for various platform-specific
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* settings.
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*
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* SSH_TUN_LINUX Use the (newer) Linux tun/tap device
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* SSH_TUN_FREEBSD Use the FreeBSD tun/tap device
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* SSH_TUN_COMPAT_AF Translate the OpenBSD address family
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* SSH_TUN_PREPEND_AF Prepend/remove the address family
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*/
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/*
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* System-specific tunnel open function
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*/
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#if defined(SSH_TUN_LINUX)
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#include <linux/if.h>
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#include <linux/if_tun.h>
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int
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sys_tun_open(int tun, int mode)
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{
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struct ifreq ifr;
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int fd = -1;
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const char *name = NULL;
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if ((fd = open("/dev/net/tun", O_RDWR)) == -1) {
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debug("%s: failed to open tunnel control interface: %s",
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__func__, strerror(errno));
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return (-1);
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}
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bzero(&ifr, sizeof(ifr));
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if (mode == SSH_TUNMODE_ETHERNET) {
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ifr.ifr_flags = IFF_TAP;
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name = "tap%d";
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} else {
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ifr.ifr_flags = IFF_TUN;
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name = "tun%d";
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}
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ifr.ifr_flags |= IFF_NO_PI;
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if (tun != SSH_TUNID_ANY) {
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if (tun > SSH_TUNID_MAX) {
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debug("%s: invalid tunnel id %x: %s", __func__,
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tun, strerror(errno));
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goto failed;
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}
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snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), name, tun);
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}
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if (ioctl(fd, TUNSETIFF, &ifr) == -1) {
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debug("%s: failed to configure tunnel (mode %d): %s", __func__,
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mode, strerror(errno));
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goto failed;
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}
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if (tun == SSH_TUNID_ANY)
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debug("%s: tunnel mode %d fd %d", __func__, mode, fd);
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else
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debug("%s: %s mode %d fd %d", __func__, ifr.ifr_name, mode, fd);
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return (fd);
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failed:
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close(fd);
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return (-1);
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}
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#endif /* SSH_TUN_LINUX */
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#ifdef SSH_TUN_FREEBSD
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#include <sys/socket.h>
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#include <net/if.h>
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#ifdef HAVE_NET_IF_TUN_H
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#include <net/if_tun.h>
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#endif
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int
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sys_tun_open(int tun, int mode)
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{
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struct ifreq ifr;
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char name[100];
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int fd = -1, sock, flag;
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const char *tunbase = "tun";
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if (mode == SSH_TUNMODE_ETHERNET) {
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#ifdef SSH_TUN_NO_L2
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debug("%s: no layer 2 tunnelling support", __func__);
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return (-1);
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#else
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tunbase = "tap";
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#endif
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}
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/* Open the tunnel device */
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if (tun <= SSH_TUNID_MAX) {
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snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
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fd = open(name, O_RDWR);
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} else if (tun == SSH_TUNID_ANY) {
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for (tun = 100; tun >= 0; tun--) {
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snprintf(name, sizeof(name), "/dev/%s%d",
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tunbase, tun);
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if ((fd = open(name, O_RDWR)) >= 0)
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break;
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}
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} else {
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debug("%s: invalid tunnel %u\n", __func__, tun);
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return (-1);
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}
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if (fd < 0) {
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debug("%s: %s open failed: %s", __func__, name,
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strerror(errno));
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return (-1);
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}
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/* Turn on tunnel headers */
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flag = 1;
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#if defined(TUNSIFHEAD) && !defined(SSH_TUN_PREPEND_AF)
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if (mode != SSH_TUNMODE_ETHERNET &&
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ioctl(fd, TUNSIFHEAD, &flag) == -1) {
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debug("%s: ioctl(%d, TUNSIFHEAD, 1): %s", __func__, fd,
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strerror(errno));
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close(fd);
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}
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#endif
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debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
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/* Set the tunnel device operation mode */
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snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
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if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
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goto failed;
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if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1)
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goto failed;
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if ((ifr.ifr_flags & IFF_UP) == 0) {
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ifr.ifr_flags |= IFF_UP;
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if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
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goto failed;
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}
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close(sock);
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return (fd);
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failed:
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if (fd >= 0)
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close(fd);
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if (sock >= 0)
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close(sock);
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debug("%s: failed to set %s mode %d: %s", __func__, name,
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mode, strerror(errno));
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return (-1);
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}
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#endif /* SSH_TUN_FREEBSD */
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/*
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* System-specific channel filters
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*/
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#if defined(SSH_TUN_FILTER)
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#define OPENBSD_AF_INET 2
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#define OPENBSD_AF_INET6 24
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int
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sys_tun_infilter(struct Channel *c, char *buf, int len)
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{
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#if defined(SSH_TUN_PREPEND_AF)
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char rbuf[CHAN_RBUF];
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struct ip *iph;
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#endif
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u_int32_t *af;
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char *ptr = buf;
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int r;
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#if defined(SSH_TUN_PREPEND_AF)
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if (len <= 0 || len > (int)(sizeof(rbuf) - sizeof(*af)))
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return (-1);
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ptr = (char *)&rbuf[0];
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bcopy(buf, ptr + sizeof(u_int32_t), len);
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len += sizeof(u_int32_t);
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af = (u_int32_t *)ptr;
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iph = (struct ip *)(ptr + sizeof(u_int32_t));
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switch (iph->ip_v) {
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case 6:
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*af = AF_INET6;
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break;
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case 4:
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default:
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*af = AF_INET;
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break;
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}
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#endif
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#if defined(SSH_TUN_COMPAT_AF)
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if (len < (int)sizeof(u_int32_t))
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return (-1);
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af = (u_int32_t *)ptr;
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if (*af == htonl(AF_INET6))
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*af = htonl(OPENBSD_AF_INET6);
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else
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*af = htonl(OPENBSD_AF_INET);
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#endif
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if ((r = sshbuf_put_string(&c->input, ptr, len)) != 0)
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fatal("%s: buffer error: %s", __func__, ssh_err(r));
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return (0);
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}
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u_char *
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sys_tun_outfilter(struct Channel *c, u_char **data, u_int *dlen)
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{
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u_char *buf;
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u_int32_t *af;
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int r;
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size_t xxx_dlen;
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/* XXX new API is incompatible with this signature. */
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if ((r = sshbuf_get_string(&c->output, data, &xxx_dlen)) != 0)
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fatal("%s: buffer error: %s", __func__, ssh_err(r));
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if (dlen != NULL)
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*dlen = xxx_dlen;
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if (*dlen < sizeof(*af))
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return (NULL);
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buf = *data;
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#if defined(SSH_TUN_PREPEND_AF)
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*dlen -= sizeof(u_int32_t);
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buf = *data + sizeof(u_int32_t);
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#elif defined(SSH_TUN_COMPAT_AF)
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af = ntohl(*(u_int32_t *)buf);
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if (*af == OPENBSD_AF_INET6)
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*af = htonl(AF_INET6);
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else
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*af = htonl(AF_INET);
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#endif
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return (buf);
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}
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#endif /* SSH_TUN_FILTER */
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