X-Git-Url: https://git.distorted.org.uk/~mdw/tripe/blobdiff_plain/1a19f86595b5c07ebf7ca7193093c54a75a15310..07212ba4fe69d4939492c67d482d017deafda9cd:/pkstream.c?ds=inline

diff --git a/pkstream.c b/pkstream.c
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--- /dev/null
+++ b/pkstream.c
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+/* -*-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 -------------------------------------------------*/