include and use OpenBSD netcat in regress/

1 files changed, 1638 insertions, 0 deletions

diff --git a/regress/netcat.c b/regress/netcat.c
new file mode 100644
index 000000000..c14d8164c
--- /dev/null
+++ b/regress/netcat.c
@@ -0,0 +1,1638 @@
+/* $OpenBSD: netcat.c,v 1.126 2014/10/30 16:08:31 tedu Exp $ */
+/*
+ * Copyright (c) 2001 Eric Jackson <ericj@monkey.org>
+ *
+ * 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ *   derived from this software without specific prior written permission.
+ *
+ * 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.
+ */
+
+/*
+ * Re-written nc(1) for OpenBSD. Original implementation by
+ * *Hobbit* <hobbit@avian.org>.
+ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <sys/uio.h>
+#include <sys/un.h>
+
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <netinet/ip.h>
+#include <arpa/telnet.h>
+
+#include <err.h>
+#include <errno.h>
+#include <netdb.h>
+#include <poll.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <limits.h>
+#include "atomicio.h"
+
+#ifndef SUN_LEN
+#define SUN_LEN(su) \
+	(sizeof(*(su)) - sizeof((su)->sun_path) + strlen((su)->sun_path))
+#endif
+
+#define PORT_MAX	65535
+#define PORT_MAX_LEN	6
+#define UNIX_DG_TMP_SOCKET_SIZE	19
+
+#define POLL_STDIN 0
+#define POLL_NETOUT 1
+#define POLL_NETIN 2
+#define POLL_STDOUT 3
+#define BUFSIZE 16384
+
+/* Command Line Options */
+int	dflag;					/* detached, no stdin */
+int	Fflag;					/* fdpass sock to stdout */
+unsigned int iflag;				/* Interval Flag */
+int	kflag;					/* More than one connect */
+int	lflag;					/* Bind to local port */
+int	Nflag;					/* shutdown() network socket */
+int	nflag;					/* Don't do name look up */
+char   *Pflag;					/* Proxy username */
+char   *pflag;					/* Localport flag */
+int	rflag;					/* Random ports flag */
+char   *sflag;					/* Source Address */
+int	tflag;					/* Telnet Emulation */
+int	uflag;					/* UDP - Default to TCP */
+int	vflag;					/* Verbosity */
+int	xflag;					/* Socks proxy */
+int	zflag;					/* Port Scan Flag */
+int	Dflag;					/* sodebug */
+int	Iflag;					/* TCP receive buffer size */
+int	Oflag;					/* TCP send buffer size */
+int	Sflag;					/* TCP MD5 signature option */
+int	Tflag = -1;				/* IP Type of Service */
+int	rtableid = -1;
+
+int timeout = -1;
+int family = AF_UNSPEC;
+char *portlist[PORT_MAX+1];
+char *unix_dg_tmp_socket;
+
+void	atelnet(int, unsigned char *, unsigned int);
+void	build_ports(char *);
+void	help(void);
+int	local_listen(char *, char *, struct addrinfo);
+void	readwrite(int);
+void	fdpass(int nfd) __attribute__((noreturn));
+int	remote_connect(const char *, const char *, struct addrinfo);
+int	timeout_connect(int, const struct sockaddr *, socklen_t);
+int	socks_connect(const char *, const char *, struct addrinfo,
+	    const char *, const char *, struct addrinfo, int, const char *);
+int	udptest(int);
+int	unix_bind(char *);
+int	unix_connect(char *);
+int	unix_listen(char *);
+void	set_common_sockopts(int);
+int	map_tos(char *, int *);
+void	report_connect(const struct sockaddr *, socklen_t);
+void	usage(int);
+ssize_t drainbuf(int, unsigned char *, size_t *);
+ssize_t fillbuf(int, unsigned char *, size_t *);
+
+int
+main(int argc, char *argv[])
+{
+	int ch, s, ret, socksv;
+	char *host, *uport;
+	struct addrinfo hints;
+	struct servent *sv;
+	socklen_t len;
+	struct sockaddr_storage cliaddr;
+	char *proxy = NULL;
+	const char *errstr, *proxyhost = "", *proxyport = NULL;
+	struct addrinfo proxyhints;
+	char unix_dg_tmp_socket_buf[UNIX_DG_TMP_SOCKET_SIZE];
+
+	ret = 1;
+	s = 0;
+	socksv = 5;
+	host = NULL;
+	uport = NULL;
+	sv = NULL;
+
+	while ((ch = getopt(argc, argv,
+	    "46DdFhI:i:klNnO:P:p:rSs:tT:UuV:vw:X:x:z")) != -1) {
+		switch (ch) {
+		case '4':
+			family = AF_INET;
+			break;
+		case '6':
+			family = AF_INET6;
+			break;
+		case 'U':
+			family = AF_UNIX;
+			break;
+		case 'X':
+			if (strcasecmp(optarg, "connect") == 0)
+				socksv = -1; /* HTTP proxy CONNECT */
+			else if (strcmp(optarg, "4") == 0)
+				socksv = 4; /* SOCKS v.4 */
+			else if (strcmp(optarg, "5") == 0)
+				socksv = 5; /* SOCKS v.5 */
+			else
+				errx(1, "unsupported proxy protocol");
+			break;
+		case 'd':
+			dflag = 1;
+			break;
+		case 'F':
+			Fflag = 1;
+			break;
+		case 'h':
+			help();
+			break;
+		case 'i':
+			iflag = strtonum(optarg, 0, UINT_MAX, &errstr);
+			if (errstr)
+				errx(1, "interval %s: %s", errstr, optarg);
+			break;
+		case 'k':
+			kflag = 1;
+			break;
+		case 'l':
+			lflag = 1;
+			break;
+		case 'N':
+			Nflag = 1;
+			break;
+		case 'n':
+			nflag = 1;
+			break;
+		case 'P':
+			Pflag = optarg;
+			break;
+		case 'p':
+			pflag = optarg;
+			break;
+		case 'r':
+			rflag = 1;
+			break;
+		case 's':
+			sflag = optarg;
+			break;
+		case 't':
+			tflag = 1;
+			break;
+		case 'u':
+			uflag = 1;
+			break;
+#ifdef SO_RTABLE
+		case 'V':
+			rtableid = (int)strtonum(optarg, 0,
+			    RT_TABLEID_MAX, &errstr);
+			if (errstr)
+				errx(1, "rtable %s: %s", errstr, optarg);
+			break;
+#endif
+		case 'v':
+			vflag = 1;
+			break;
+		case 'w':
+			timeout = strtonum(optarg, 0, INT_MAX / 1000, &errstr);
+			if (errstr)
+				errx(1, "timeout %s: %s", errstr, optarg);
+			timeout *= 1000;
+			break;
+		case 'x':
+			xflag = 1;
+			if ((proxy = strdup(optarg)) == NULL)
+				err(1, NULL);
+			break;
+		case 'z':
+			zflag = 1;
+			break;
+		case 'D':
+			Dflag = 1;
+			break;
+		case 'I':
+			Iflag = strtonum(optarg, 1, 65536 << 14, &errstr);
+			if (errstr != NULL)
+				errx(1, "TCP receive window %s: %s",
+				    errstr, optarg);
+			break;
+		case 'O':
+			Oflag = strtonum(optarg, 1, 65536 << 14, &errstr);
+			if (errstr != NULL)
+				errx(1, "TCP send window %s: %s",
+				    errstr, optarg);
+			break;
+		case 'S':
+			Sflag = 1;
+			break;
+		case 'T':
+			errstr = NULL;
+			errno = 0;
+			if (map_tos(optarg, &Tflag))
+				break;
+			if (strlen(optarg) > 1 && optarg[0] == '0' &&
+			    optarg[1] == 'x')
+				Tflag = (int)strtol(optarg, NULL, 16);
+			else
+				Tflag = (int)strtonum(optarg, 0, 255,
+				    &errstr);
+			if (Tflag < 0 || Tflag > 255 || errstr || errno)
+				errx(1, "illegal tos value %s", optarg);
+			break;
+		default:
+			usage(1);
+		}
+	}
+	argc -= optind;
+	argv += optind;
+
+	/* Cruft to make sure options are clean, and used properly. */
+	if (argv[0] && !argv[1] && family == AF_UNIX) {
+		host = argv[0];
+		uport = NULL;
+	} else if (argv[0] && !argv[1]) {
+		if  (!lflag)
+			usage(1);
+		uport = argv[0];
+		host = NULL;
+	} else if (argv[0] && argv[1]) {
+		host = argv[0];
+		uport = argv[1];
+	} else
+		usage(1);
+
+	if (lflag && sflag)
+		errx(1, "cannot use -s and -l");
+	if (lflag && pflag)
+		errx(1, "cannot use -p and -l");
+	if (lflag && zflag)
+		errx(1, "cannot use -z and -l");
+	if (!lflag && kflag)
+		errx(1, "must use -l with -k");
+
+	/* Get name of temporary socket for unix datagram client */
+	if ((family == AF_UNIX) && uflag && !lflag) {
+		if (sflag) {
+			unix_dg_tmp_socket = sflag;
+		} else {
+			strlcpy(unix_dg_tmp_socket_buf, "/tmp/nc.XXXXXXXXXX",
+				UNIX_DG_TMP_SOCKET_SIZE);
+			if (mktemp(unix_dg_tmp_socket_buf) == NULL)
+				err(1, "mktemp");
+			unix_dg_tmp_socket = unix_dg_tmp_socket_buf;
+		}
+	}
+
+	/* Initialize addrinfo structure. */
+	if (family != AF_UNIX) {
+		memset(&hints, 0, sizeof(struct addrinfo));
+		hints.ai_family = family;
+		hints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
+		hints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
+		if (nflag)
+			hints.ai_flags |= AI_NUMERICHOST;
+	}
+
+	if (xflag) {
+		if (uflag)
+			errx(1, "no proxy support for UDP mode");
+
+		if (lflag)
+			errx(1, "no proxy support for listen");
+
+		if (family == AF_UNIX)
+			errx(1, "no proxy support for unix sockets");
+
+		/* XXX IPv6 transport to proxy would probably work */
+		if (family == AF_INET6)
+			errx(1, "no proxy support for IPv6");
+
+		if (sflag)
+			errx(1, "no proxy support for local source address");
+
+		proxyhost = strsep(&proxy, ":");
+		proxyport = proxy;
+
+		memset(&proxyhints, 0, sizeof(struct addrinfo));
+		proxyhints.ai_family = family;
+		proxyhints.ai_socktype = SOCK_STREAM;
+		proxyhints.ai_protocol = IPPROTO_TCP;
+		if (nflag)
+			proxyhints.ai_flags |= AI_NUMERICHOST;
+	}
+
+	if (lflag) {
+		int connfd;
+		ret = 0;
+
+		if (family == AF_UNIX) {
+			if (uflag)
+				s = unix_bind(host);
+			else
+				s = unix_listen(host);
+		}
+
+		/* Allow only one connection at a time, but stay alive. */
+		for (;;) {
+			if (family != AF_UNIX)
+				s = local_listen(host, uport, hints);
+			if (s < 0)
+				err(1, NULL);
+			/*
+			 * For UDP and -k, don't connect the socket, let it
+			 * receive datagrams from multiple socket pairs.
+			 */
+			if (uflag && kflag)
+				readwrite(s);
+			/*
+			 * For UDP and not -k, we will use recvfrom() initially
+			 * to wait for a caller, then use the regular functions
+			 * to talk to the caller.
+			 */
+			else if (uflag && !kflag) {
+				int rv, plen;
+				char buf[16384];
+				struct sockaddr_storage z;
+
+				len = sizeof(z);
+				plen = 2048;
+				rv = recvfrom(s, buf, plen, MSG_PEEK,
+				    (struct sockaddr *)&z, &len);
+				if (rv < 0)
+					err(1, "recvfrom");
+
+				rv = connect(s, (struct sockaddr *)&z, len);
+				if (rv < 0)
+					err(1, "connect");
+
+				if (vflag)
+					report_connect((struct sockaddr *)&z, len);
+
+				readwrite(s);
+			} else {
+				len = sizeof(cliaddr);
+				connfd = accept(s, (struct sockaddr *)&cliaddr,
+				    &len);
+				if (connfd == -1) {
+					/* For now, all errnos are fatal */
+					err(1, "accept");
+				}
+				if (vflag)
+					report_connect((struct sockaddr *)&cliaddr, len);
+
+				readwrite(connfd);
+				close(connfd);
+			}
+
+			if (family != AF_UNIX)
+				close(s);
+			else if (uflag) {
+				if (connect(s, NULL, 0) < 0)
+					err(1, "connect");
+			}
+
+			if (!kflag)
+				break;
+		}
+	} else if (family == AF_UNIX) {
+		ret = 0;
+
+		if ((s = unix_connect(host)) > 0 && !zflag) {
+			readwrite(s);
+			close(s);
+		} else
+			ret = 1;
+
+		if (uflag)
+			unlink(unix_dg_tmp_socket);
+		exit(ret);
+
+	} else {
+		int i = 0;
+
+		/* Construct the portlist[] array. */
+		build_ports(uport);
+
+		/* Cycle through portlist, connecting to each port. */
+		for (i = 0; portlist[i] != NULL; i++) {
+			if (s)
+				close(s);
+
+			if (xflag)
+				s = socks_connect(host, portlist[i], hints,
+				    proxyhost, proxyport, proxyhints, socksv,
+				    Pflag);
+			else
+				s = remote_connect(host, portlist[i], hints);
+
+			if (s < 0)
+				continue;
+
+			ret = 0;
+			if (vflag || zflag) {
+				/* For UDP, make sure we are connected. */
+				if (uflag) {
+					if (udptest(s) == -1) {
+						ret = 1;
+						continue;
+					}
+				}
+
+				/* Don't look up port if -n. */
+				if (nflag)
+					sv = NULL;
+				else {
+					sv = getservbyport(
+					    ntohs(atoi(portlist[i])),
+					    uflag ? "udp" : "tcp");
+				}
+
+				fprintf(stderr,
+				    "Connection to %s %s port [%s/%s] "
+				    "succeeded!\n", host, portlist[i],
+				    uflag ? "udp" : "tcp",
+				    sv ? sv->s_name : "*");
+			}
+			if (Fflag)
+				fdpass(s);
+			else if (!zflag)
+				readwrite(s);
+		}
+	}
+
+	if (s)
+		close(s);
+
+	exit(ret);
+}
+
+/*
+ * unix_bind()
+ * Returns a unix socket bound to the given path
+ */
+int
+unix_bind(char *path)
+{
+	struct sockaddr_un sun;
+	int s;
+
+	/* Create unix domain socket. */
+	if ((s = socket(AF_UNIX, uflag ? SOCK_DGRAM : SOCK_STREAM,
+	     0)) < 0)
+		return (-1);
+
+	memset(&sun, 0, sizeof(struct sockaddr_un));
+	sun.sun_family = AF_UNIX;
+
+	if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
+	    sizeof(sun.sun_path)) {
+		close(s);
+		errno = ENAMETOOLONG;
+		return (-1);
+	}
+
+	if (bind(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
+		close(s);
+		return (-1);
+	}
+	return (s);
+}
+
+/*
+ * unix_connect()
+ * Returns a socket connected to a local unix socket. Returns -1 on failure.
+ */
+int
+unix_connect(char *path)
+{
+	struct sockaddr_un sun;
+	int s;
+
+	if (uflag) {
+		if ((s = unix_bind(unix_dg_tmp_socket)) < 0)
+			return (-1);
+	} else {
+		if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
+			return (-1);
+	}
+	(void)fcntl(s, F_SETFD, FD_CLOEXEC);
+
+	memset(&sun, 0, sizeof(struct sockaddr_un));
+	sun.sun_family = AF_UNIX;
+
+	if (strlcpy(sun.sun_path, path, sizeof(sun.sun_path)) >=
+	    sizeof(sun.sun_path)) {
+		close(s);
+		errno = ENAMETOOLONG;
+		return (-1);
+	}
+	if (connect(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
+		close(s);
+		return (-1);
+	}
+	return (s);
+
+}
+
+/*
+ * unix_listen()
+ * Create a unix domain socket, and listen on it.
+ */
+int
+unix_listen(char *path)
+{
+	int s;
+	if ((s = unix_bind(path)) < 0)
+		return (-1);
+
+	if (listen(s, 5) < 0) {
+		close(s);
+		return (-1);
+	}
+	return (s);
+}
+
+/*
+ * remote_connect()
+ * Returns a socket connected to a remote host. Properly binds to a local
+ * port or source address if needed. Returns -1 on failure.
+ */
+int
+remote_connect(const char *host, const char *port, struct addrinfo hints)
+{
+	struct addrinfo *res, *res0;
+	int s, error;
+#ifdef SO_RTABLE
+	int on = 1;
+#endif
+
+	if ((error = getaddrinfo(host, port, &hints, &res)))
+		errx(1, "getaddrinfo: %s", gai_strerror(error));
+
+	res0 = res;
+	do {
+		if ((s = socket(res0->ai_family, res0->ai_socktype,
+		    res0->ai_protocol)) < 0)
+			continue;
+
+#ifdef SO_RTABLE
+		if (rtableid >= 0 && (setsockopt(s, SOL_SOCKET, SO_RTABLE,
+		    &rtableid, sizeof(rtableid)) == -1))
+			err(1, "setsockopt SO_RTABLE");
+#endif
+		/* Bind to a local port or source address if specified. */
+		if (sflag || pflag) {
+			struct addrinfo ahints, *ares;
+
+#ifdef SO_BINDANY
+			/* try SO_BINDANY, but don't insist */
+			setsockopt(s, SOL_SOCKET, SO_BINDANY, &on, sizeof(on));
+#endif
+			memset(&ahints, 0, sizeof(struct addrinfo));
+			ahints.ai_family = res0->ai_family;
+			ahints.ai_socktype = uflag ? SOCK_DGRAM : SOCK_STREAM;
+			ahints.ai_protocol = uflag ? IPPROTO_UDP : IPPROTO_TCP;
+			ahints.ai_flags = AI_PASSIVE;
+			if ((error = getaddrinfo(sflag, pflag, &ahints, &ares)))
+				errx(1, "getaddrinfo: %s", gai_strerror(error));
+
+			if (bind(s, (struct sockaddr *)ares->ai_addr,
+			    ares->ai_addrlen) < 0)
+				err(1, "bind failed");
+			freeaddrinfo(ares);
+		}
+
+		set_common_sockopts(s);
+
+		if (timeout_connect(s, res0->ai_addr, res0->ai_addrlen) == 0)
+			break;
+		else if (vflag)
+			warn("connect to %s port %s (%s) failed", host, port,
+			    uflag ? "udp" : "tcp");
+
+		close(s);
+		s = -1;
+	} while ((res0 = res0->ai_next) != NULL);
+
+	freeaddrinfo(res);
+
+	return (s);
+}
+
+int
+timeout_connect(int s, const struct sockaddr *name, socklen_t namelen)
+{
+	struct pollfd pfd;
+	socklen_t optlen;
+	int flags = 0, optval;
+	int ret;
+
+	if (timeout != -1) {
+		flags = fcntl(s, F_GETFL, 0);
+		if (fcntl(s, F_SETFL, flags | O_NONBLOCK) == -1)
+			err(1, "set non-blocking mode");
+	}
+
+	if ((ret = connect(s, name, namelen)) != 0 && errno == EINPROGRESS) {
+		pfd.fd = s;
+		pfd.events = POLLOUT;
+		if ((ret = poll(&pfd, 1, timeout)) == 1) {
+			optlen = sizeof(optval);
+			if ((ret = getsockopt(s, SOL_SOCKET, SO_ERROR,
+			    &optval, &optlen)) == 0) {
+				errno = optval;
+				ret = optval == 0 ? 0 : -1;
+			}
+		} else if (ret == 0) {
+			errno = ETIMEDOUT;
+			ret = -1;
+		} else
+			err(1, "poll failed");
+	}
+
+	if (timeout != -1 && fcntl(s, F_SETFL, flags) == -1)
+		err(1, "restoring flags");
+
+	return (ret);
+}
+
+/*
+ * local_listen()
+ * Returns a socket listening on a local port, binds to specified source
+ * address. Returns -1 on failure.
+ */
+int
+local_listen(char *host, char *port, struct addrinfo hints)
+{
+	struct addrinfo *res, *res0;
+	int s, ret, x = 1;
+	int error;
+
+	/* Allow nodename to be null. */
+	hints.ai_flags |= AI_PASSIVE;
+
+	/*
+	 * In the case of binding to a wildcard address
+	 * default to binding to an ipv4 address.
+	 */
+	if (host == NULL && hints.ai_family == AF_UNSPEC)
+		hints.ai_family = AF_INET;
+
+	if ((error = getaddrinfo(host, port, &hints, &res)))
+		errx(1, "getaddrinfo: %s", gai_strerror(error));
+
+	res0 = res;
+	do {
+		if ((s = socket(res0->ai_family, res0->ai_socktype,
+		    res0->ai_protocol)) < 0)
+			continue;
+
+#ifdef SO_RTABLE
+		if (rtableid >= 0 && (setsockopt(s, SOL_SOCKET, SO_RTABLE,
+		    &rtableid, sizeof(rtableid)) == -1))
+			err(1, "setsockopt SO_RTABLE");
+#endif
+
+		ret = setsockopt(s, SOL_SOCKET, SO_REUSEPORT, &x, sizeof(x));
+		if (ret == -1)
+			err(1, NULL);
+
+		set_common_sockopts(s);
+
+		if (bind(s, (struct sockaddr *)res0->ai_addr,
+		    res0->ai_addrlen) == 0)
+			break;
+
+		close(s);
+		s = -1;
+	} while ((res0 = res0->ai_next) != NULL);
+
+	if (!uflag && s != -1) {
+		if (listen(s, 1) < 0)
+			err(1, "listen");
+	}
+
+	freeaddrinfo(res);
+
+	return (s);
+}
+
+/*
+ * readwrite()
+ * Loop that polls on the network file descriptor and stdin.
+ */
+void
+readwrite(int net_fd)
+{
+	struct pollfd pfd[4];
+	int stdin_fd = STDIN_FILENO;
+	int stdout_fd = STDOUT_FILENO;
+	unsigned char netinbuf[BUFSIZE];
+	size_t netinbufpos = 0;
+	unsigned char stdinbuf[BUFSIZE];
+	size_t stdinbufpos = 0;
+	int n, num_fds;
+	ssize_t ret;
+
+	/* don't read from stdin if requested */
+	if (dflag)
+		stdin_fd = -1;
+
+	/* stdin */
+	pfd[POLL_STDIN].fd = stdin_fd;
+	pfd[POLL_STDIN].events = POLLIN;
+
+	/* network out */
+	pfd[POLL_NETOUT].fd = net_fd;
+	pfd[POLL_NETOUT].events = 0;
+
+	/* network in */
+	pfd[POLL_NETIN].fd = net_fd;
+	pfd[POLL_NETIN].events = POLLIN;
+
+	/* stdout */
+	pfd[POLL_STDOUT].fd = stdout_fd;
+	pfd[POLL_STDOUT].events = 0;
+
+	while (1) {
+		/* both inputs are gone, buffers are empty, we are done */
+		if (pfd[POLL_STDIN].fd == -1 && pfd[POLL_NETIN].fd == -1
+		    && stdinbufpos == 0 && netinbufpos == 0) {
+			close(net_fd);
+			return;
+		}
+		/* both outputs are gone, we can't continue */
+		if (pfd[POLL_NETOUT].fd == -1 && pfd[POLL_STDOUT].fd == -1) {
+			close(net_fd);
+			return;
+		}
+		/* listen and net in gone, queues empty, done */
+		if (lflag && pfd[POLL_NETIN].fd == -1
+		    && stdinbufpos == 0 && netinbufpos == 0) {
+			close(net_fd);
+			return;
+		}
+
+		/* help says -i is for "wait between lines sent". We read and
+		 * write arbitrary amounts of data, and we don't want to start
+		 * scanning for newlines, so this is as good as it gets */
+		if (iflag)
+			sleep(iflag);
+
+		/* poll */
+		num_fds = poll(pfd, 4, timeout);
+
+		/* treat poll errors */
+		if (num_fds == -1) {
+			close(net_fd);
+			err(1, "polling error");
+		}
+
+		/* timeout happened */
+		if (num_fds == 0)
+			return;
+
+		/* treat socket error conditions */
+		for (n = 0; n < 4; n++) {
+			if (pfd[n].revents & (POLLERR|POLLNVAL)) {
+				pfd[n].fd = -1;
+			}
+		}
+		/* reading is possible after HUP */
+		if (pfd[POLL_STDIN].events & POLLIN &&
+		    pfd[POLL_STDIN].revents & POLLHUP &&
+		    ! (pfd[POLL_STDIN].revents & POLLIN))
+				pfd[POLL_STDIN].fd = -1;
+
+		if (pfd[POLL_NETIN].events & POLLIN &&
+		    pfd[POLL_NETIN].revents & POLLHUP &&
+		    ! (pfd[POLL_NETIN].revents & POLLIN))
+				pfd[POLL_NETIN].fd = -1;
+
+		if (pfd[POLL_NETOUT].revents & POLLHUP) {
+			if (Nflag)
+				shutdown(pfd[POLL_NETOUT].fd, SHUT_WR);
+			pfd[POLL_NETOUT].fd = -1;
+		}
+		/* if HUP, stop watching stdout */
+		if (pfd[POLL_STDOUT].revents & POLLHUP)
+			pfd[POLL_STDOUT].fd = -1;
+		/* if no net out, stop watching stdin */
+		if (pfd[POLL_NETOUT].fd == -1)
+			pfd[POLL_STDIN].fd = -1;
+		/* if no stdout, stop watching net in */
+		if (pfd[POLL_STDOUT].fd == -1) {
+			if (pfd[POLL_NETIN].fd != -1)
+				shutdown(pfd[POLL_NETIN].fd, SHUT_RD);
+			pfd[POLL_NETIN].fd = -1;
+		}
+
+		/* try to read from stdin */
+		if (pfd[POLL_STDIN].revents & POLLIN && stdinbufpos < BUFSIZE) {
+			ret = fillbuf(pfd[POLL_STDIN].fd, stdinbuf,
+			    &stdinbufpos);
+			/* error or eof on stdin - remove from pfd */
+			if (ret == 0 || ret == -1)
+				pfd[POLL_STDIN].fd = -1;
+			/* read something - poll net out */
+			if (stdinbufpos > 0)
+				pfd[POLL_NETOUT].events = POLLOUT;
+			/* filled buffer - remove self from polling */
+			if (stdinbufpos == BUFSIZE)
+				pfd[POLL_STDIN].events = 0;
+		}
+		/* try to write to network */
+		if (pfd[POLL_NETOUT].revents & POLLOUT && stdinbufpos > 0) {
+			ret = drainbuf(pfd[POLL_NETOUT].fd, stdinbuf,
+			    &stdinbufpos);
+			if (ret == -1)
+				pfd[POLL_NETOUT].fd = -1;
+			/* buffer empty - remove self from polling */
+			if (stdinbufpos == 0)
+				pfd[POLL_NETOUT].events = 0;
+			/* buffer no longer full - poll stdin again */
+			if (stdinbufpos < BUFSIZE)
+				pfd[POLL_STDIN].events = POLLIN;
+		}
+		/* try to read from network */
+		if (pfd[POLL_NETIN].revents & POLLIN && netinbufpos < BUFSIZE) {
+			ret = fillbuf(pfd[POLL_NETIN].fd, netinbuf,
+			    &netinbufpos);
+			if (ret == -1)
+				pfd[POLL_NETIN].fd = -1;
+			/* eof on net in - remove from pfd */
+			if (ret == 0) {
+				shutdown(pfd[POLL_NETIN].fd, SHUT_RD);
+				pfd[POLL_NETIN].fd = -1;
+			}
+			/* read something - poll stdout */
+			if (netinbufpos > 0)
+				pfd[POLL_STDOUT].events = POLLOUT;
+			/* filled buffer - remove self from polling */
+			if (netinbufpos == BUFSIZE)
+				pfd[POLL_NETIN].events = 0;
+			/* handle telnet */
+			if (tflag)
+				atelnet(pfd[POLL_NETIN].fd, netinbuf,
+				    netinbufpos);
+		}
+		/* try to write to stdout */
+		if (pfd[POLL_STDOUT].revents & POLLOUT && netinbufpos > 0) {
+			ret = drainbuf(pfd[POLL_STDOUT].fd, netinbuf,
+			    &netinbufpos);
+			if (ret == -1)
+				pfd[POLL_STDOUT].fd = -1;
+			/* buffer empty - remove self from polling */
+			if (netinbufpos == 0)
+				pfd[POLL_STDOUT].events = 0;
+			/* buffer no longer full - poll net in again */
+			if (netinbufpos < BUFSIZE)
+				pfd[POLL_NETIN].events = POLLIN;
+		}
+
+		/* stdin gone and queue empty? */
+		if (pfd[POLL_STDIN].fd == -1 && stdinbufpos == 0) {
+			if (pfd[POLL_NETOUT].fd != -1 && Nflag)
+				shutdown(pfd[POLL_NETOUT].fd, SHUT_WR);
+			pfd[POLL_NETOUT].fd = -1;
+		}
+		/* net in gone and queue empty? */
+		if (pfd[POLL_NETIN].fd == -1 && netinbufpos == 0) {
+			pfd[POLL_STDOUT].fd = -1;
+		}
+	}
+}
+
+ssize_t
+drainbuf(int fd, unsigned char *buf, size_t *bufpos)
+{
+	ssize_t n;
+	ssize_t adjust;
+
+	n = write(fd, buf, *bufpos);
+	/* don't treat EAGAIN, EINTR as error */
+	if (n == -1 && (errno == EAGAIN || errno == EINTR))
+		n = -2;
+	if (n <= 0)
+		return n;
+	/* adjust buffer */
+	adjust = *bufpos - n;
+	if (adjust > 0)
+		memmove(buf, buf + n, adjust);
+	*bufpos -= n;
+	return n;
+}
+
+
+ssize_t
+fillbuf(int fd, unsigned char *buf, size_t *bufpos)
+{
+	size_t num = BUFSIZE - *bufpos;
+	ssize_t n;
+
+	n = read(fd, buf + *bufpos, num);
+	/* don't treat EAGAIN, EINTR as error */
+	if (n == -1 && (errno == EAGAIN || errno == EINTR))
+		n = -2;
+	if (n <= 0)
+		return n;
+	*bufpos += n;
+	return n;
+}
+
+/*
+ * fdpass()
+ * Pass the connected file descriptor to stdout and exit.
+ */
+void
+fdpass(int nfd)
+{
+	struct msghdr mh;
+	union {
+		struct cmsghdr hdr;
+		char buf[CMSG_SPACE(sizeof(int))];
+	} cmsgbuf;
+	struct cmsghdr *cmsg;
+	struct iovec iov;
+	char c = '\0';
+	ssize_t r;
+	struct pollfd pfd;
+
+	/* Avoid obvious stupidity */
+	if (isatty(STDOUT_FILENO))
+		errx(1, "Cannot pass file descriptor to tty");
+
+	bzero(&mh, sizeof(mh));
+	bzero(&cmsgbuf, sizeof(cmsgbuf));
+	bzero(&iov, sizeof(iov));
+	bzero(&pfd, sizeof(pfd));
+
+	mh.msg_control = (caddr_t)&cmsgbuf.buf;
+	mh.msg_controllen = sizeof(cmsgbuf.buf);
+	cmsg = CMSG_FIRSTHDR(&mh);
+	cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+	cmsg->cmsg_level = SOL_SOCKET;
+	cmsg->cmsg_type = SCM_RIGHTS;
+	*(int *)CMSG_DATA(cmsg) = nfd;
+
+	iov.iov_base = &c;
+	iov.iov_len = 1;
+	mh.msg_iov = &iov;
+	mh.msg_iovlen = 1;
+
+	bzero(&pfd, sizeof(pfd));
+	pfd.fd = STDOUT_FILENO;
+	for (;;) {
+		r = sendmsg(STDOUT_FILENO, &mh, 0);
+		if (r == -1) {
+			if (errno == EAGAIN || errno == EINTR) {
+				pfd.events = POLLOUT;
+				if (poll(&pfd, 1, -1) == -1)
+					err(1, "poll");
+				continue;
+			}
+			err(1, "sendmsg");
+		} else if (r == -1)
+			errx(1, "sendmsg: unexpected return value %zd", r);
+		else
+			break;
+	}
+	exit(0);
+}
+
+/* Deal with RFC 854 WILL/WONT DO/DONT negotiation. */
+void
+atelnet(int nfd, unsigned char *buf, unsigned int size)
+{
+	unsigned char *p, *end;
+	unsigned char obuf[4];
+
+	if (size < 3)
+		return;
+	end = buf + size - 2;
+
+	for (p = buf; p < end; p++) {
+		if (*p != IAC)
+			continue;
+
+		obuf[0] = IAC;
+		p++;
+		if ((*p == WILL) || (*p == WONT))
+			obuf[1] = DONT;
+		else if ((*p == DO) || (*p == DONT))
+			obuf[1] = WONT;
+		else
+			continue;
+
+		p++;
+		obuf[2] = *p;
+		if (atomicio(vwrite, nfd, obuf, 3) != 3)
+			warn("Write Error!");
+	}
+}
+
+/*
+ * build_ports()
+ * Build an array of ports in portlist[], listing each port
+ * that we should try to connect to.
+ */
+void
+build_ports(char *p)
+{
+	const char *errstr;
+	char *n;
+	int hi, lo, cp;
+	int x = 0;
+
+	if ((n = strchr(p, '-')) != NULL) {
+		*n = '\0';
+		n++;
+
+		/* Make sure the ports are in order: lowest->highest. */
+		hi = strtonum(n, 1, PORT_MAX, &errstr);
+		if (errstr)
+			errx(1, "port number %s: %s", errstr, n);
+		lo = strtonum(p, 1, PORT_MAX, &errstr);
+		if (errstr)
+			errx(1, "port number %s: %s", errstr, p);
+
+		if (lo > hi) {
+			cp = hi;
+			hi = lo;
+			lo = cp;
+		}
+
+		/* Load ports sequentially. */
+		for (cp = lo; cp <= hi; cp++) {
+			portlist[x] = calloc(1, PORT_MAX_LEN);
+			if (portlist[x] == NULL)
+				err(1, NULL);
+			snprintf(portlist[x], PORT_MAX_LEN, "%d", cp);
+			x++;
+		}
+
+		/* Randomly swap ports. */
+		if (rflag) {
+			int y;
+			char *c;
+
+			for (x = 0; x <= (hi - lo); x++) {
+				y = (arc4random() & 0xFFFF) % (hi - lo);
+				c = portlist[x];
+				portlist[x] = portlist[y];
+				portlist[y] = c;
+			}
+		}
+	} else {
+		hi = strtonum(p, 1, PORT_MAX, &errstr);
+		if (errstr)
+			errx(1, "port number %s: %s", errstr, p);
+		portlist[0] = strdup(p);
+		if (portlist[0] == NULL)
+			err(1, NULL);
+	}
+}
+
+/*
+ * udptest()
+ * Do a few writes to see if the UDP port is there.
+ * Fails once PF state table is full.
+ */
+int
+udptest(int s)
+{
+	int i, ret;
+
+	for (i = 0; i <= 3; i++) {
+		if (write(s, "X", 1) == 1)
+			ret = 1;
+		else
+			ret = -1;
+	}
+	return (ret);
+}
+
+void
+set_common_sockopts(int s)
+{
+	int x = 1;
+
+	if (Sflag) {
+		if (setsockopt(s, IPPROTO_TCP, TCP_MD5SIG,
+			&x, sizeof(x)) == -1)
+			err(1, NULL);
+	}
+	if (Dflag) {
+		if (setsockopt(s, SOL_SOCKET, SO_DEBUG,
+			&x, sizeof(x)) == -1)
+			err(1, NULL);
+	}
+	if (Tflag != -1) {
+		if (setsockopt(s, IPPROTO_IP, IP_TOS,
+		    &Tflag, sizeof(Tflag)) == -1)
+			err(1, "set IP ToS");
+	}
+	if (Iflag) {
+		if (setsockopt(s, SOL_SOCKET, SO_RCVBUF,
+		    &Iflag, sizeof(Iflag)) == -1)
+			err(1, "set TCP receive buffer size");
+	}
+	if (Oflag) {
+		if (setsockopt(s, SOL_SOCKET, SO_SNDBUF,
+		    &Oflag, sizeof(Oflag)) == -1)
+			err(1, "set TCP send buffer size");
+	}
+}
+
+int
+map_tos(char *s, int *val)
+{
+	/* DiffServ Codepoints and other TOS mappings */
+	const struct toskeywords {
+		const char	*keyword;
+		int		 val;
+	} *t, toskeywords[] = {
+		{ "af11",		IPTOS_DSCP_AF11 },
+		{ "af12",		IPTOS_DSCP_AF12 },
+		{ "af13",		IPTOS_DSCP_AF13 },
+		{ "af21",		IPTOS_DSCP_AF21 },
+		{ "af22",		IPTOS_DSCP_AF22 },
+		{ "af23",		IPTOS_DSCP_AF23 },
+		{ "af31",		IPTOS_DSCP_AF31 },
+		{ "af32",		IPTOS_DSCP_AF32 },
+		{ "af33",		IPTOS_DSCP_AF33 },
+		{ "af41",		IPTOS_DSCP_AF41 },
+		{ "af42",		IPTOS_DSCP_AF42 },
+		{ "af43",		IPTOS_DSCP_AF43 },
+		{ "critical",		IPTOS_PREC_CRITIC_ECP },
+		{ "cs0",		IPTOS_DSCP_CS0 },
+		{ "cs1",		IPTOS_DSCP_CS1 },
+		{ "cs2",		IPTOS_DSCP_CS2 },
+		{ "cs3",		IPTOS_DSCP_CS3 },
+		{ "cs4",		IPTOS_DSCP_CS4 },
+		{ "cs5",		IPTOS_DSCP_CS5 },
+		{ "cs6",		IPTOS_DSCP_CS6 },
+		{ "cs7",		IPTOS_DSCP_CS7 },
+		{ "ef",			IPTOS_DSCP_EF },
+		{ "inetcontrol",	IPTOS_PREC_INTERNETCONTROL },
+		{ "lowdelay",		IPTOS_LOWDELAY },
+		{ "netcontrol",		IPTOS_PREC_NETCONTROL },
+		{ "reliability",	IPTOS_RELIABILITY },
+		{ "throughput",		IPTOS_THROUGHPUT },
+		{ NULL, 		-1 },
+	};
+
+	for (t = toskeywords; t->keyword != NULL; t++) {
+		if (strcmp(s, t->keyword) == 0) {
+			*val = t->val;
+			return (1);
+		}
+	}
+
+	return (0);
+}
+
+void
+report_connect(const struct sockaddr *sa, socklen_t salen)
+{
+	char remote_host[NI_MAXHOST];
+	char remote_port[NI_MAXSERV];
+	int herr;
+	int flags = NI_NUMERICSERV;
+	
+	if (nflag)
+		flags |= NI_NUMERICHOST;
+	
+	if ((herr = getnameinfo(sa, salen,
+	    remote_host, sizeof(remote_host),
+	    remote_port, sizeof(remote_port),
+	    flags)) != 0) {
+		if (herr == EAI_SYSTEM)
+			err(1, "getnameinfo");
+		else
+			errx(1, "getnameinfo: %s", gai_strerror(herr));
+	}
+	
+	fprintf(stderr,
+	    "Connection from %s %s "
+	    "received!\n", remote_host, remote_port);
+}
+
+void
+help(void)
+{
+	usage(0);
+	fprintf(stderr, "\tCommand Summary:\n\
+	\t-4		Use IPv4\n\
+	\t-6		Use IPv6\n\
+	\t-D		Enable the debug socket option\n\
+	\t-d		Detach from stdin\n\
+	\t-F		Pass socket fd\n\
+	\t-h		This help text\n\
+	\t-I length	TCP receive buffer length\n\
+	\t-i secs\t	Delay interval for lines sent, ports scanned\n\
+	\t-k		Keep inbound sockets open for multiple connects\n\
+	\t-l		Listen mode, for inbound connects\n\
+	\t-N		Shutdown the network socket after EOF on stdin\n\
+	\t-n		Suppress name/port resolutions\n\
+	\t-O length	TCP send buffer length\n\
+	\t-P proxyuser\tUsername for proxy authentication\n\
+	\t-p port\t	Specify local port for remote connects\n\
+	\t-r		Randomize remote ports\n\
+	\t-S		Enable the TCP MD5 signature option\n\
+	\t-s addr\t	Local source address\n\
+	\t-T toskeyword\tSet IP Type of Service\n\
+	\t-t		Answer TELNET negotiation\n\
+	\t-U		Use UNIX domain socket\n\
+	\t-u		UDP mode\n\
+	\t-V rtable	Specify alternate routing table\n\
+	\t-v		Verbose\n\
+	\t-w secs\t	Timeout for connects and final net reads\n\
+	\t-X proto	Proxy protocol: \"4\", \"5\" (SOCKS) or \"connect\"\n\
+	\t-x addr[:port]\tSpecify proxy address and port\n\
+	\t-z		Zero-I/O mode [used for scanning]\n\
+	Port numbers can be individual or ranges: lo-hi [inclusive]\n");
+	exit(1);
+}
+
+void
+usage(int ret)
+{
+	fprintf(stderr,
+	    "usage: nc [-46DdFhklNnrStUuvz] [-I length] [-i interval] [-O length]\n"
+	    "\t  [-P proxy_username] [-p source_port] [-s source] [-T ToS]\n"
+	    "\t  [-V rtable] [-w timeout] [-X proxy_protocol]\n"
+	    "\t  [-x proxy_address[:port]] [destination] [port]\n");
+	if (ret)
+		exit(1);
+}
+
+/* *** src/usr.bin/nc/socks.c *** */
+
+
+/*	$OpenBSD: socks.c,v 1.20 2012/03/08 09:56:28 espie Exp $	*/
+
+/*
+ * Copyright (c) 1999 Niklas Hallqvist.  All rights reserved.
+ * Copyright (c) 2004, 2005 Damien Miller.  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/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+
+#include <err.h>
+#include <errno.h>
+#include <netdb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <resolv.h>
+
+#define SOCKS_PORT	"1080"
+#define HTTP_PROXY_PORT	"3128"
+#define HTTP_MAXHDRS	64
+#define SOCKS_V5	5
+#define SOCKS_V4	4
+#define SOCKS_NOAUTH	0
+#define SOCKS_NOMETHOD	0xff
+#define SOCKS_CONNECT	1
+#define SOCKS_IPV4	1
+#define SOCKS_DOMAIN	3
+#define SOCKS_IPV6	4
+
+int	remote_connect(const char *, const char *, struct addrinfo);
+int	socks_connect(const char *, const char *, struct addrinfo,
+	    const char *, const char *, struct addrinfo, int,
+	    const char *);
+
+static int
+decode_addrport(const char *h, const char *p, struct sockaddr *addr,
+    socklen_t addrlen, int v4only, int numeric)
+{
+	int r;
+	struct addrinfo hints, *res;
+
+	bzero(&hints, sizeof(hints));
+	hints.ai_family = v4only ? PF_INET : PF_UNSPEC;
+	hints.ai_flags = numeric ? AI_NUMERICHOST : 0;
+	hints.ai_socktype = SOCK_STREAM;
+	r = getaddrinfo(h, p, &hints, &res);
+	/* Don't fatal when attempting to convert a numeric address */
+	if (r != 0) {
+		if (!numeric) {
+			errx(1, "getaddrinfo(\"%.64s\", \"%.64s\"): %s", h, p,
+			    gai_strerror(r));
+		}
+		return (-1);
+	}
+	if (addrlen < res->ai_addrlen) {
+		freeaddrinfo(res);
+		errx(1, "internal error: addrlen < res->ai_addrlen");
+	}
+	memcpy(addr, res->ai_addr, res->ai_addrlen);
+	freeaddrinfo(res);
+	return (0);
+}
+
+static int
+proxy_read_line(int fd, char *buf, size_t bufsz)
+{
+	size_t off;
+
+	for(off = 0;;) {
+		if (off >= bufsz)
+			errx(1, "proxy read too long");
+		if (atomicio(read, fd, buf + off, 1) != 1)
+			err(1, "proxy read");
+		/* Skip CR */
+		if (buf[off] == '\r')
+			continue;
+		if (buf[off] == '\n') {
+			buf[off] = '\0';
+			break;
+		}
+		off++;
+	}
+	return (off);
+}
+
+static const char *
+getproxypass(const char *proxyuser, const char *proxyhost)
+{
+	char prompt[512];
+	static char pw[256];
+
+	snprintf(prompt, sizeof(prompt), "Proxy password for %s@%s: ",
+	   proxyuser, proxyhost);
+	if (readpassphrase(prompt, pw, sizeof(pw), RPP_REQUIRE_TTY) == NULL)
+		errx(1, "Unable to read proxy passphrase");
+	return (pw);
+}
+
+int
+socks_connect(const char *host, const char *port,
+    struct addrinfo hints __attribute__ ((__unused__)),
+    const char *proxyhost, const char *proxyport, struct addrinfo proxyhints,
+    int socksv, const char *proxyuser)
+{
+	int proxyfd, r, authretry = 0;
+	size_t hlen, wlen;
+	unsigned char buf[1024];
+	size_t cnt;
+	struct sockaddr_storage addr;
+	struct sockaddr_in *in4 = (struct sockaddr_in *)&addr;
+	struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)&addr;
+	in_port_t serverport;
+	const char *proxypass = NULL;
+
+	if (proxyport == NULL)
+		proxyport = (socksv == -1) ? HTTP_PROXY_PORT : SOCKS_PORT;
+
+	/* Abuse API to lookup port */
+	if (decode_addrport("0.0.0.0", port, (struct sockaddr *)&addr,
+	    sizeof(addr), 1, 1) == -1)
+		errx(1, "unknown port \"%.64s\"", port);
+	serverport = in4->sin_port;
+
+ again:
+	if (authretry++ > 3)
+		errx(1, "Too many authentication failures");
+
+	proxyfd = remote_connect(proxyhost, proxyport, proxyhints);
+
+	if (proxyfd < 0)
+		return (-1);
+
+	if (socksv == 5) {
+		if (decode_addrport(host, port, (struct sockaddr *)&addr,
+		    sizeof(addr), 0, 1) == -1)
+			addr.ss_family = 0; /* used in switch below */
+
+		/* Version 5, one method: no authentication */
+		buf[0] = SOCKS_V5;
+		buf[1] = 1;
+		buf[2] = SOCKS_NOAUTH;
+		cnt = atomicio(vwrite, proxyfd, buf, 3);
+		if (cnt != 3)
+			err(1, "write failed (%zu/3)", cnt);
+
+		cnt = atomicio(read, proxyfd, buf, 2);
+		if (cnt != 2)
+			err(1, "read failed (%zu/3)", cnt);
+
+		if (buf[1] == SOCKS_NOMETHOD)
+			errx(1, "authentication method negotiation failed");
+
+		switch (addr.ss_family) {
+		case 0:
+			/* Version 5, connect: domain name */
+
+			/* Max domain name length is 255 bytes */
+			hlen = strlen(host);
+			if (hlen > 255)
+				errx(1, "host name too long for SOCKS5");
+			buf[0] = SOCKS_V5;
+			buf[1] = SOCKS_CONNECT;
+			buf[2] = 0;
+			buf[3] = SOCKS_DOMAIN;
+			buf[4] = hlen;
+			memcpy(buf + 5, host, hlen);			
+			memcpy(buf + 5 + hlen, &serverport, sizeof serverport);
+			wlen = 7 + hlen;
+			break;
+		case AF_INET:
+			/* Version 5, connect: IPv4 address */
+			buf[0] = SOCKS_V5;
+			buf[1] = SOCKS_CONNECT;
+			buf[2] = 0;
+			buf[3] = SOCKS_IPV4;
+			memcpy(buf + 4, &in4->sin_addr, sizeof in4->sin_addr);
+			memcpy(buf + 8, &in4->sin_port, sizeof in4->sin_port);
+			wlen = 10;
+			break;
+		case AF_INET6:
+			/* Version 5, connect: IPv6 address */
+			buf[0] = SOCKS_V5;
+			buf[1] = SOCKS_CONNECT;
+			buf[2] = 0;
+			buf[3] = SOCKS_IPV6;
+			memcpy(buf + 4, &in6->sin6_addr, sizeof in6->sin6_addr);
+			memcpy(buf + 20, &in6->sin6_port,
+			    sizeof in6->sin6_port);
+			wlen = 22;
+			break;
+		default:
+			errx(1, "internal error: silly AF");
+		}
+
+		cnt = atomicio(vwrite, proxyfd, buf, wlen);
+		if (cnt != wlen)
+			err(1, "write failed (%zu/%zu)", cnt, wlen);
+
+		cnt = atomicio(read, proxyfd, buf, 4);
+		if (cnt != 4)
+			err(1, "read failed (%zu/4)", cnt);
+		if (buf[1] != 0)
+			errx(1, "connection failed, SOCKS error %d", buf[1]);
+		switch (buf[3]) {
+		case SOCKS_IPV4:
+			cnt = atomicio(read, proxyfd, buf + 4, 6);
+			if (cnt != 6)
+				err(1, "read failed (%zu/6)", cnt);
+			break;
+		case SOCKS_IPV6:
+			cnt = atomicio(read, proxyfd, buf + 4, 18);
+			if (cnt != 18)
+				err(1, "read failed (%zu/18)", cnt);
+			break;
+		default:
+			errx(1, "connection failed, unsupported address type");
+		}
+	} else if (socksv == 4) {
+		/* This will exit on lookup failure */
+		decode_addrport(host, port, (struct sockaddr *)&addr,
+		    sizeof(addr), 1, 0);
+
+		/* Version 4 */
+		buf[0] = SOCKS_V4;
+		buf[1] = SOCKS_CONNECT;	/* connect */
+		memcpy(buf + 2, &in4->sin_port, sizeof in4->sin_port);
+		memcpy(buf + 4, &in4->sin_addr, sizeof in4->sin_addr);
+		buf[8] = 0;	/* empty username */
+		wlen = 9;
+
+		cnt = atomicio(vwrite, proxyfd, buf, wlen);
+		if (cnt != wlen)
+			err(1, "write failed (%zu/%zu)", cnt, wlen);
+
+		cnt = atomicio(read, proxyfd, buf, 8);
+		if (cnt != 8)
+			err(1, "read failed (%zu/8)", cnt);
+		if (buf[1] != 90)
+			errx(1, "connection failed, SOCKS error %d", buf[1]);
+	} else if (socksv == -1) {
+		/* HTTP proxy CONNECT */
+
+		/* Disallow bad chars in hostname */
+		if (strcspn(host, "\r\n\t []:") != strlen(host))
+			errx(1, "Invalid hostname");
+
+		/* Try to be sane about numeric IPv6 addresses */
+		if (strchr(host, ':') != NULL) {
+			r = snprintf(buf, sizeof(buf),
+			    "CONNECT [%s]:%d HTTP/1.0\r\n",
+			    host, ntohs(serverport));
+		} else {
+			r = snprintf(buf, sizeof(buf),
+			    "CONNECT %s:%d HTTP/1.0\r\n",
+			    host, ntohs(serverport));
+		}
+		if (r == -1 || (size_t)r >= sizeof(buf))
+			errx(1, "hostname too long");
+		r = strlen(buf);
+
+		cnt = atomicio(vwrite, proxyfd, buf, r);
+		if (cnt != (size_t)r)
+			err(1, "write failed (%zu/%d)", cnt, r);
+
+		if (authretry > 1) {
+			char resp[1024];
+
+			proxypass = getproxypass(proxyuser, proxyhost);
+			r = snprintf(buf, sizeof(buf), "%s:%s",
+			    proxyuser, proxypass);
+			if (r == -1 || (size_t)r >= sizeof(buf) ||
+			    b64_ntop(buf, strlen(buf), resp,
+			    sizeof(resp)) == -1)
+				errx(1, "Proxy username/password too long");
+			r = snprintf(buf, sizeof(buf), "Proxy-Authorization: "
+			    "Basic %s\r\n", resp);
+			if (r == -1 || (size_t)r >= sizeof(buf))
+				errx(1, "Proxy auth response too long");
+			r = strlen(buf);
+			if ((cnt = atomicio(vwrite, proxyfd, buf, r)) != (size_t)r)
+				err(1, "write failed (%zu/%d)", cnt, r);
+		}
+
+		/* Terminate headers */
+		if ((r = atomicio(vwrite, proxyfd, "\r\n", 2)) != 2)
+			err(1, "write failed (2/%d)", r);
+
+		/* Read status reply */
+		proxy_read_line(proxyfd, buf, sizeof(buf));
+		if (proxyuser != NULL &&
+		    strncmp(buf, "HTTP/1.0 407 ", 12) == 0) {
+			if (authretry > 1) {
+				fprintf(stderr, "Proxy authentication "
+				    "failed\n");
+			}
+			close(proxyfd);
+			goto again;
+		} else if (strncmp(buf, "HTTP/1.0 200 ", 12) != 0 &&
+		    strncmp(buf, "HTTP/1.1 200 ", 12) != 0)
+			errx(1, "Proxy error: \"%s\"", buf);
+
+		/* Headers continue until we hit an empty line */
+		for (r = 0; r < HTTP_MAXHDRS; r++) {
+			proxy_read_line(proxyfd, buf, sizeof(buf));
+			if (*buf == '\0')
+				break;
+		}
+		if (*buf != '\0')
+			errx(1, "Too many proxy headers received");
+	} else
+		errx(1, "Unknown proxy protocol %d", socksv);
+
+	return (proxyfd);
+}
+