1 /* $OpenBSD: util.c,v 1.18 2004/01/22 16:10:30 beck Exp $ */
2 /* $DragonFly: src/libexec/ftp-proxy/util.c,v 1.2 2005/02/24 15:38:09 joerg Exp $ */
5 * Copyright (c) 1996-2001
6 * Obtuse Systems Corporation. All rights reserved.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the Obtuse Systems nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE OBTUSE SYSTEMS AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL OBTUSE
24 * SYSTEMS CORPORATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
25 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
26 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
27 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
29 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
31 * OF THE POSSIBILITY OF SUCH DAMAGE.
35 #include <sys/types.h>
36 #include <sys/socket.h>
37 #include <sys/ioctl.h>
39 #include <netinet/in.h>
40 #include <netinet/in_systm.h>
42 #include <net/pf/pfvar.h>
44 #include <arpa/inet.h>
60 extern int ReverseMode;
64 in_addr_t Bind_Addr = INADDR_NONE;
66 void debuglog(int debug_level, const char *fmt, ...);
69 debuglog(int debug_level, const char *fmt, ...)
74 if (Debug_Level >= debug_level)
75 vsyslog(LOG_DEBUG, fmt, ap);
80 get_proxy_env(int connected_fd, struct sockaddr_in *real_server_sa_ptr,
81 struct sockaddr_in *client_sa_ptr, struct sockaddr_in *proxy_sa_ptr)
83 struct pfioc_natlook natlook;
87 slen = sizeof(*proxy_sa_ptr);
88 if (getsockname(connected_fd, (struct sockaddr *)proxy_sa_ptr,
90 syslog(LOG_ERR, "getsockname() failed (%m)");
93 slen = sizeof(*client_sa_ptr);
94 if (getpeername(connected_fd, (struct sockaddr *)client_sa_ptr,
96 syslog(LOG_ERR, "getpeername() failed (%m)");
104 * Build up the pf natlook structure.
105 * Just for IPv4 right now
107 memset((void *)&natlook, 0, sizeof(natlook));
108 natlook.af = AF_INET;
109 natlook.saddr.addr32[0] = client_sa_ptr->sin_addr.s_addr;
110 natlook.daddr.addr32[0] = proxy_sa_ptr->sin_addr.s_addr;
111 natlook.proto = IPPROTO_TCP;
112 natlook.sport = client_sa_ptr->sin_port;
113 natlook.dport = proxy_sa_ptr->sin_port;
114 natlook.direction = PF_OUT;
117 * Open the pf device and lookup the mapping pair to find
118 * the original address we were supposed to connect to.
120 fd = open("/dev/pf", O_RDWR);
122 syslog(LOG_ERR, "cannot open /dev/pf (%m)");
123 exit(EX_UNAVAILABLE);
126 if (ioctl(fd, DIOCNATLOOK, &natlook) == -1) {
128 "pf nat lookup failed %s:%hu (%m)",
129 inet_ntoa(client_sa_ptr->sin_addr),
130 ntohs(client_sa_ptr->sin_port));
137 * Now jam the original address and port back into the into
138 * destination sockaddr_in for the proxy to deal with.
140 memset((void *)real_server_sa_ptr, 0, sizeof(struct sockaddr_in));
141 real_server_sa_ptr->sin_port = natlook.rdport;
142 real_server_sa_ptr->sin_addr.s_addr = natlook.rdaddr.addr32[0];
143 real_server_sa_ptr->sin_len = sizeof(struct sockaddr_in);
144 real_server_sa_ptr->sin_family = AF_INET;
150 * Transfer one unit of data across a pair of sockets
152 * A unit of data is as much as we get with a single read(2) call.
155 xfer_data(const char *what_read,int from_fd, int to_fd,
156 struct in_addr from __unused, struct in_addr to __unused)
158 int rlen, offset, xerrno, mark, flags = 0;
162 * Are we at the OOB mark?
164 if (ioctl(from_fd, SIOCATMARK, &mark) < 0) {
166 syslog(LOG_ERR, "cannot ioctl(SIOCATMARK) socket from %s (%m)",
172 flags = MSG_OOB; /* Yes - at the OOB mark */
175 rlen = recv(from_fd, tbuf, sizeof(tbuf), flags);
176 if (rlen == -1 && flags == MSG_OOB && errno == EINVAL) {
177 /* OOB didn't work */
179 rlen = recv(from_fd, tbuf, sizeof(tbuf), flags);
182 debuglog(3, "EOF on read socket");
184 } else if (rlen == -1) {
185 if (errno == EAGAIN || errno == EINTR)
188 syslog(LOG_ERR, "xfer_data (%s): failed (%m) with flags 0%o",
194 debuglog(3, "got %d bytes from socket", rlen);
196 while (offset < rlen) {
199 wlen = send(to_fd, &tbuf[offset], rlen - offset,
202 debuglog(3, "zero-length write");
204 } else if (wlen == -1) {
205 if (errno == EAGAIN || errno == EINTR)
208 syslog(LOG_INFO, "write failed (%m)");
212 debuglog(3, "wrote %d bytes to socket",wlen);
221 * get_backchannel_socket gets us a socket bound somewhere in a
222 * particular range of ports
225 get_backchannel_socket(int type, int min_port, int max_port, int start_port,
226 int direction, struct sockaddr_in *sap)
231 * Make sure that direction is 'defined' and that min_port is not
232 * greater than max_port.
237 /* by default we go up by one port until we find one */
238 if (min_port > max_port) {
243 count = 1 + max_port - min_port;
246 * Pick a port we can bind to from within the range we want.
247 * If the caller specifies -1 as the starting port number then
248 * we pick one somewhere in the range to try.
249 * This is an optimization intended to speedup port selection and
250 * has NOTHING to do with security.
252 if (start_port == -1)
253 start_port = (arc4random() % count) + min_port;
255 if (start_port < min_port || start_port > max_port) {
260 while (count-- > 0) {
261 struct sockaddr_in sa;
264 fd = socket(AF_INET, type, 0);
266 bzero(&sa, sizeof sa);
267 sa.sin_family = AF_INET;
268 if (Bind_Addr == INADDR_NONE)
270 sa.sin_addr.s_addr = INADDR_ANY;
272 sa.sin_addr.s_addr = sap->sin_addr.s_addr;
274 sa.sin_addr.s_addr = Bind_Addr;
277 * Indicate that we want to reuse a port if it happens that the
278 * port in question was a listen port recently.
281 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one,
285 sa.sin_port = htons(start_port);
287 if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) == 0) {
293 if (errno != EADDRINUSE)
296 /* if it's in use, try the next port */
299 start_port += direction;
300 if (start_port < min_port)
301 start_port = max_port;
302 else if (start_port > max_port)
303 start_port = min_port;