--- /dev/null
+.\" -*-nroff-*-
+.\".
+.de hP
+.IP
+\h'-\w'\fB\\$1\ \fP'u'\fB\\$1\ \fP\c
+..
+.de VS
+.sp 1
+.RS
+.nf
+.ft B
+..
+.de VE
+.ft R
+.fi
+.RE
+.sp 1
+..
+.ie t \{\
+. ds o \(bu
+. ds ss \s8\u
+. ds se \d\s0
+. if \n(.g \{\
+. fam P
+. \}
+.\}
+.el \{\
+. ds o o
+. ds ss ^
+. ds se
+.\}
+.TH pkstream 1 "23 April 2003" "Straylight/Edgeware" "TrIPE: Trivial IP Encryption"
+.SH "NAME"
+pkstream \- forward UDP packets over streams
+.SH "SYNOPSIS"
+.B pkstream
+.RB [ \-l
+.IR port ]
+.RB [ \-p
+.IR addr ]
+.RB [ \-c
+.IR addr \c
+.BR : \c
+.IR port ]
+.br
+
+.IB addr : port
+.IB addr : port
+.SH "DESCRIPTION"
+The
+.B pkstream
+program forwards UDP packets over some kind of reliable stream. It
+understands TCP sockets natively; anything else has to be fudged up
+using some kind of port forwarder like
+.BR fw (1),
+.BR ssh (1),
+.BR stunnel (1),
+etc. It's intended, among other things, to provide a transport for
+.B tripe (8)
+packets where there are annoying firewalls in the way.
+.SS "Command-line arguments"
+The two
+.RI ` addr \c
+.BR : \c
+.IR port '
+pairs on the command-line are respectively the UDP port that
+.B pkstream
+should listen on, and the port which it should receive packets from and
+send them to.
+.PP
+By default,
+.B pkstream
+will parse packets from the stream attached to its standard input and
+send them to its UDP peer; and it will write packets it reads from its
+UDP port to the stream attached to its standard output. The program
+will quit when its input stream closes.
+.PP
+This behaviour can be modified by passing suitable options:
+.TP
+.B "\-h, \-\-help"
+Writes a brief description of the command-line options available to
+standard output and exits with status 0.
+.TP
+.B "\-v, \-\-version"
+Writes
+.BR tripe 's
+version number to standard output and exits with status 0.
+.TP
+.B "\-u, \-\-usage"
+Writes a brief usage summary to standard output and exits with status 0.
+.TP
+.BI "\-l, \-\-listen=" port
+Listen for connections on the given TCP
+.IR port .
+Only one connection is allowed at a time. When a connection is
+accepted, forward UDP packets over the TCP stream until it closes; then
+wait for another connection.
+.BI "\-p, \-\-peer=" addr
+Only accept TCP connections from
+.IR addr .
+This option only makes sense in conjunction with
+.BR \-l .
+.TP
+.BI "\-c, \-\-connect=" addr : port
+Connect to the given
+.I addr
+and
+.I port
+and forward packets over the TCP connection rather than using stdin and
+stdout.
+.SH "Protocol"
+The stream protocol is very simple. Each packet is preceded by a
+two-octet length field in network byte order. The length is number of
+octets in the following packet (i.e., it does
+.I not
+include the length field itself). There is no padding between packets.
+The only way a stream can be invalid is if it stops in the middle of a
+packet.
+.SH "BUGS"
+The code hasn't been audited. It may contain security bugs. If you
+find one, please inform the author
+.IR immediately .
+.SH "SEE ALSO"
+.BR fw (1),
+.BR ssh (1),
+.BR stunnel (1),
+.BR tripe (8).
+.SH "AUTHOR"
+Mark Wooding, <mdw@nsict.org>
--- /dev/null
+/* -*-c-*-
+ *
+ * $Id: pkstream.c,v 1.1 2003/04/23 12:53:28 mdw Exp $
+ *
+ * Forwarding UDP packets over a stream
+ *
+ * (c) 2003 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of Trivial IP Encryption (TrIPE).
+ *
+ * TrIPE is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * TrIPE is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with TrIPE; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+/*----- Revision history --------------------------------------------------*
+ *
+ * $Log: pkstream.c,v $
+ * Revision 1.1 2003/04/23 12:53:28 mdw
+ * New pkstream program.
+ *
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include "config.h"
+
+#include <ctype.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/uio.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+
+#include <mLib/alloc.h>
+#include <mLib/bits.h>
+#include <mLib/dstr.h>
+#include <mLib/fdflags.h>
+#include <mLib/mdwopt.h>
+#include <mLib/quis.h>
+#include <mLib/report.h>
+#include <mLib/sel.h>
+#include <mLib/selpk.h>
+
+/*----- Data structures ---------------------------------------------------*/
+
+typedef struct pk {
+ struct pk *next; /* Next packet in the chain */
+ octet *p, *o; /* Buffer start and current posn */
+ size_t n; /* Size of packet remaining */
+} pk;
+
+typedef struct pkstream {
+ unsigned f; /* Flags... */
+#define PKF_FULL 1u /* Buffer is full: stop reading */
+ sel_file r, w; /* Read and write selectors */
+ pk *pks, **pk_tail; /* Packet queue */
+ size_t npk, szpk; /* Number and size of data */
+ selpk p; /* Packet parser */
+} pkstream;
+
+typedef struct connwait {
+ sel_file a; /* Selector */
+ struct sockaddr_in me; /* Who I'm meant to be */
+ struct in_addr peer; /* Who my peer is */
+} connwait;
+
+/*----- Static variables --------------------------------------------------*/
+
+static sel_state sel;
+static connwait cw;
+static int fd_udp;
+static size_t pk_nmax = 128, pk_szmax = 1024 * 1024;
+
+/*----- Main code ---------------------------------------------------------*/
+
+static int nonblockify(int fd)
+{
+ return (fdflags(fd, O_NONBLOCK, O_NONBLOCK, 0, 0));
+}
+
+static int cloexec(int fd)
+{
+ return (fdflags(fd, 0, 0, FD_CLOEXEC, FD_CLOEXEC));
+}
+
+static void dolisten(void);
+
+static void doclose(pkstream *p)
+{
+ pk *pk, *ppk;
+ close(p->w.fd);
+ close(p->p.reader.fd);
+ selpk_destroy(&p->p);
+ if (!(p->f & PKF_FULL))
+ sel_rmfile(&p->r);
+ if (p->npk)
+ sel_rmfile(&p->w);
+ for (pk = p->pks; pk; pk = ppk) {
+ ppk = pk->next;
+ xfree(pk->p);
+ xfree(pk);
+ }
+ xfree(p);
+ if (cw.me.sin_port != 0)
+ dolisten();
+ else
+ exit(0);
+}
+
+static void rdtcp(octet *b, size_t sz, pkbuf *pk, size_t *k, void *vp)
+{
+ pkstream *p = vp;
+ size_t pksz;
+
+ if (!sz) {
+ doclose(p);
+ return;
+ }
+ pksz = LOAD16(b);
+ if (pksz + 2 == sz) {
+ write(fd_udp, b + 2, pksz);
+ selpk_want(&p->p, 2);
+ } else {
+ selpk_want(&p->p, pksz + 2);
+ *k = sz;
+ }
+}
+
+static void wrtcp(int fd, unsigned mode, void *vp)
+{
+#define NPK 16
+ struct iovec iov[NPK];
+ pkstream *p = vp;
+ size_t i;
+ ssize_t n;
+ pk *pk, *ppk;
+
+ for (i = 0, pk = p->pks; i < NPK && pk; i++, pk = pk->next) {
+ iov[i].iov_base = pk->o;
+ iov[i].iov_len = pk->n;
+ }
+
+ if ((n = writev(fd, iov, i)) < 0) {
+ if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
+ return;
+ moan("couldn't write to TCP socket: %s", strerror(errno));
+ doclose(p);
+ return;
+ }
+
+ p->szpk -= n;
+ for (pk = p->pks; n && pk; pk = ppk) {
+ ppk = pk->next;
+ if (pk->n <= n) {
+ p->npk--;
+ n -= pk->n;
+ xfree(pk->p);
+ xfree(pk);
+ } else {
+ pk->n -= n;
+ pk->o += n;
+ break;
+ }
+ }
+ p->pks = pk;
+ if (!pk) {
+ p->pk_tail = &p->pks;
+ sel_rmfile(&p->w);
+ }
+ if ((p->f & PKF_FULL) && p->npk < pk_nmax && p->szpk < pk_szmax) {
+ p->f &= ~PKF_FULL;
+ sel_addfile(&p->r);
+ }
+}
+
+static void rdudp(int fd, unsigned mode, void *vp)
+{
+ octet buf[65536];
+ ssize_t n;
+ pkstream *p = vp;
+ pk *pk;
+
+ if ((n = read(fd, buf, sizeof(buf))) < 0) {
+ if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
+ return;
+ moan("couldn't read from UDP socket: %s", strerror(errno));
+ return;
+ }
+ pk = xmalloc(sizeof(*pk));
+ pk->next = 0;
+ pk->p = xmalloc(n + 2);
+ STORE16(pk->p, n);
+ memcpy(pk->p + 2, buf, n);
+ pk->o = pk->p;
+ pk->n = n + 2;
+ *p->pk_tail = pk;
+ p->pk_tail = &pk->next;
+ if (!p->npk)
+ sel_addfile(&p->w);
+ sel_force(&p->w);
+ p->npk++;
+ p->szpk += n + 2;
+ if (p->npk >= pk_nmax || p->szpk >= pk_szmax) {
+ sel_rmfile(&p->r);
+ p->f |= PKF_FULL;
+ }
+}
+
+static void dofwd(int fd_in, int fd_out)
+{
+ pkstream *p = xmalloc(sizeof(*p));
+ sel_initfile(&sel, &p->r, fd_udp, SEL_READ, rdudp, p);
+ sel_initfile(&sel, &p->w, fd_out, SEL_WRITE, wrtcp, p);
+ selpk_init(&p->p, &sel, fd_in, rdtcp, p);
+ selpk_want(&p->p, 2);
+ p->pks = 0;
+ p->pk_tail = &p->pks;
+ p->npk = p->szpk = 0;
+ p->f = 0;
+ sel_addfile(&p->r);
+}
+
+static void doaccept(int fd_s, unsigned mode, void *p)
+{
+ int fd;
+ struct sockaddr_in sin;
+ socklen_t sz = sizeof(sin);
+
+ if ((fd = accept(fd_s, (struct sockaddr *)&sin, &sz)) < 0) {
+ if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
+ return;
+ moan("couldn't accept incoming connection: %s", strerror(errno));
+ return;
+ }
+ if (cw.peer.s_addr != INADDR_ANY &&
+ cw.peer.s_addr != sin.sin_addr.s_addr) {
+ close(fd);
+ moan("rejecting connection from %s", inet_ntoa(sin.sin_addr));
+ return;
+ }
+ if (nonblockify(fd) || cloexec(fd)) {
+ close(fd);
+ moan("couldn't accept incoming connection: %s", strerror(errno));
+ return;
+ }
+ dofwd(fd, fd);
+ close(fd_s);
+ sel_rmfile(&cw.a);
+}
+
+static void dolisten(void)
+{
+ int fd;
+ int opt = 1;
+
+ if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0 ||
+ bind(fd, (struct sockaddr *)&cw.me, sizeof(cw.me)) ||
+ setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) ||
+ listen(fd, 1) || nonblockify(fd) || cloexec(fd))
+ die(1, "couldn't set up listening socket: %s", strerror(errno));
+ sel_initfile(&sel, &cw.a, fd, SEL_READ, doaccept, 0);
+ sel_addfile(&cw.a);
+}
+
+static void parseaddr(const char *pp, struct in_addr *a, unsigned short *pt)
+{
+ char *p = xstrdup(pp);
+ char *q = 0;
+ if (a && pt) {
+ strtok(p, ":");
+ q = strtok(0, "");
+ if (!q)
+ die(1, "missing port number in address `%s'", p);
+ } else if (pt) {
+ q = p;
+ }
+
+ if (a) {
+ struct hostent *h;
+ if ((h = gethostbyname(p)) == 0)
+ die(1, "unknown host `%s'", p);
+ memcpy(a, h->h_addr, sizeof(*a));
+ }
+
+ if (pt) {
+ struct servent *s;
+ char *qq;
+ unsigned long n;
+ if ((s = getservbyname(q, "tcp")) != 0)
+ *pt = s->s_port;
+ else if ((n = strtoul(q, &qq, 0)) == 0 || *qq || n > 0xffff)
+ die(1, "bad port number `%s'", q);
+ else
+ *pt = htons(n);
+ }
+}
+
+static void usage(FILE *fp)
+{
+ pquis(fp,
+ "Usage: $ [-l PORT] [-p ADDR] [-c ADDR:PORT] ADDR:PORT ADDR:PORT\n");
+}
+
+static void version(FILE *fp)
+{
+ pquis(fp, "$, tripe version " VERSION "\n");
+}
+
+static void help(FILE *fp)
+{
+ version(fp);
+ fputc('\n', fp);
+ usage(fp);
+ fputs("\n\
+Options:\n\
+\n\
+-h, --help Display this help text.\n\
+-v, --version Display version number.\n\
+-u, --usage Display pointless usage message.\n\
+\n\
+-l, --listen=PORT Listen for connections to TCP PORT.\n\
+-p, --peer=PORT Only accept connections from IP ADDR.\n\
+-c, --connect=ADDR:PORT Connect to IP ADDR, TCP PORT.\n\
+\n\
+Forwards UDP packets over a reliable stream. By default, uses stdin and\n\
+stdout; though it can use TCP sockets instead.\n\
+", fp);
+}
+
+int main(int argc, char *argv[])
+{
+ unsigned f = 0;
+ unsigned short pt;
+ struct sockaddr_in connaddr;
+ struct sockaddr_in udp_me, udp_peer;
+ int len = 65536;
+
+#define f_bogus 1u
+
+ ego(argv[0]);
+ connaddr.sin_family = AF_INET;
+ cw.me.sin_family = AF_INET;
+ cw.me.sin_addr.s_addr = INADDR_ANY;
+ cw.me.sin_port = 0;
+ cw.peer.s_addr = INADDR_ANY;
+ sel_init(&sel);
+ for (;;) {
+ static struct option opt[] = {
+ { "help", 0, 0, 'h' },
+ { "version", 0, 0, 'v' },
+ { "usage", 0, 0, 'u' },
+ { "listen", OPTF_ARGREQ, 0, 'l' },
+ { "peer", OPTF_ARGREQ, 0, 'p' },
+ { "connect", OPTF_ARGREQ, 0, 'c' },
+ { 0, 0, 0, 0 }
+ };
+ int i;
+
+ i = mdwopt(argc, argv, "hvul:p:c:", opt, 0, 0, 0);
+ if (i < 0)
+ break;
+ switch (i) {
+ case 'h':
+ help(stdout);
+ exit(0);
+ case 'v':
+ version(stdout);
+ exit(0);
+ case 'u':
+ usage(stdout);
+ exit(0);
+ case 'l':
+ parseaddr(optarg, 0, &pt);
+ cw.me.sin_port = pt;
+ break;
+ case 'p':
+ parseaddr(optarg, &cw.peer, 0);
+ break;
+ case 'c':
+ parseaddr(optarg, &connaddr.sin_addr, &pt);
+ connaddr.sin_port = pt;
+ break;
+ default:
+ f |= f_bogus;
+ break;
+ }
+ }
+ if (optind + 2 != argc || (f & f_bogus)) {
+ usage(stderr);
+ exit(1);
+ }
+
+ udp_me.sin_family = udp_peer.sin_family = AF_INET;
+ parseaddr(argv[optind], &udp_me.sin_addr, &pt);
+ udp_me.sin_port = pt;
+ parseaddr(argv[optind + 1], &udp_peer.sin_addr, &pt);
+ udp_peer.sin_port = pt;
+
+ if ((fd_udp = socket(PF_INET, SOCK_DGRAM, 0)) < 0 ||
+ bind(fd_udp, (struct sockaddr *)&udp_me, sizeof(udp_me)) ||
+ connect(fd_udp, (struct sockaddr *)&udp_peer, sizeof(udp_peer)) ||
+ setsockopt(fd_udp, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) ||
+ setsockopt(fd_udp, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len)) ||
+ nonblockify(fd_udp) || cloexec(fd_udp))
+ die(1, "couldn't set up UDP socket: %s", strerror(errno));
+
+ if (cw.me.sin_port != 0)
+ dolisten();
+ else if (connaddr.sin_addr.s_addr != INADDR_ANY) {
+ int fd;
+ if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0 ||
+ connect(fd, (struct sockaddr *)&connaddr, sizeof(connaddr)) ||
+ nonblockify(fd) || cloexec(fd))
+ die(1, "couldn't connect to TCP server: %s", strerror(errno));
+ dofwd(fd, fd);
+ } else
+ dofwd(STDIN_FILENO, STDOUT_FILENO);
+
+ for (;;)
+ sel_select(&sel);
+ return (0);
+}
+
+/*----- That's all, folks -------------------------------------------------*/
~mdw / tripe / commitdiff