passt, pasta: Introduce command-line options and port re-mapping

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 1163 insertions, 0 deletions

diff --git a/conf.c b/conf.c
new file mode 100644
index 0000000..79353a1
--- /dev/null
+++ b/conf.c
@@ -0,0 +1,1163 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+/* PASST - Plug A Simple Socket Transport
+ *  for qemu/UNIX domain socket mode
+ *
+ * PASTA - Pack A Subtle Tap Abstraction
+ *  for network namespace/tap device mode
+ *
+ * conf.c - Configuration settings and option parsing
+ *
+ * Copyright (c) 2020-2021 Red Hat GmbH
+ * Author: Stefano Brivio <sbrivio@redhat.com>
+ */
+
+#define _GNU_SOURCE
+#include <sched.h>
+#include <getopt.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <ifaddrs.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <syslog.h>
+#include <time.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <linux/if_ether.h>
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+
+#include "util.h"
+#include "passt.h"
+#include "udp.h"
+#include "tcp.h"
+
+/**
+ * struct get_bound_ports_ns_arg - Arguments for get_bound_ports_ns()
+ * @c:		Execution context
+ * @proto:	Protocol number (IPPROTO_TCP or IPPROTO_UDP)
+ */
+struct get_bound_ports_ns_arg {
+	struct ctx *c;
+	uint8_t proto;
+};
+
+/**
+ * get_bound_ports_ns() - Get maps of ports  namespace with bound sockets
+ * @arg:	See struct get_bound_ports_ns_arg
+ *
+ * Return: 0
+ */
+static int get_bound_ports_ns(void *arg)
+{
+	struct get_bound_ports_ns_arg *a = (struct get_bound_ports_ns_arg *)arg;
+	struct ctx *c = a->c;
+
+	if (!c->pasta_pid || ns_enter(c->pasta_pid))
+		return 0;
+
+	if (a->proto == IPPROTO_UDP) {
+		procfs_scan_listen("udp",  c->udp.port_to_tap);
+		procfs_scan_listen("udp6", c->udp.port_to_tap);
+
+		procfs_scan_listen("tcp",  c->udp.port_to_tap);
+		procfs_scan_listen("tcp6", c->udp.port_to_tap);
+	} else if (a->proto == IPPROTO_TCP) {
+		procfs_scan_listen("tcp",  c->tcp.port_to_tap);
+		procfs_scan_listen("tcp6", c->tcp.port_to_tap);
+	}
+
+	return 0;
+}
+
+/**
+ * get_bound_ports() - Get maps of ports in init namespace with bound sockets
+ * @c:		Execution context
+ * @proto:	Protocol number (IPPROTO_TCP or IPPROTO_UDP)
+ */
+static void get_bound_ports(struct ctx *c, uint8_t proto)
+{
+	if (proto == IPPROTO_UDP) {
+		procfs_scan_listen("udp",  c->udp.port_to_init);
+		procfs_scan_listen("udp6", c->udp.port_to_init);
+
+		procfs_scan_listen("tcp",  c->udp.port_to_init);
+		procfs_scan_listen("tcp6", c->udp.port_to_init);
+	} else if (proto == IPPROTO_TCP) {
+		procfs_scan_listen("tcp",  c->tcp.port_to_init);
+		procfs_scan_listen("tcp6", c->tcp.port_to_init);
+	}
+}
+
+enum conf_port_type {
+	PORT_SPEC = 1,
+	PORT_NONE,
+	PORT_AUTO,
+	PORT_ALL,
+};
+
+static int conf_ports(struct ctx *c, char optname, const char *optarg,
+		      enum conf_port_type *set)
+{
+	int start_src = -1, end_src = -1, start_dst = -1, end_dst = -1;
+	void (*remap)(in_port_t port, in_port_t delta);
+	const char *p;
+	uint8_t *map;
+	char *sep;
+
+	if (optname == 't') {
+		map = c->tcp.port_to_tap;
+		remap = tcp_remap_to_tap;
+	} else if (optname == 'T') {
+		map = c->tcp.port_to_init;
+		remap = tcp_remap_to_init;
+	} else if (optname == 'u') {
+		map = c->udp.port_to_tap;
+		remap = udp_remap_to_tap;
+	} else if (optname == 'U') {
+		map = c->udp.port_to_init;
+		remap = udp_remap_to_init;
+	} else {	/* For gcc -O3 */
+		return 0;
+	}
+
+	if (!strcmp(optarg, "none")) {
+		if (*set)
+			return -EINVAL;
+		*set = PORT_NONE;
+		return 0;
+	}
+
+	if (!strcmp(optarg, "auto")) {
+		if (*set || c->mode != MODE_PASTA)
+			return -EINVAL;
+		*set = PORT_AUTO;
+		return 0;
+	}
+
+	if (!strcmp(optarg, "all")) {
+		if (*set || c->mode != MODE_PASST)
+			return -EINVAL;
+		*set = PORT_ALL;
+		memset(map, 0xff, PORT_EPHEMERAL_MIN / 8);
+		return 0;
+	}
+
+	if (*set > PORT_SPEC)
+		return -EINVAL;
+
+	*set = PORT_SPEC;
+
+	if (strspn(optarg, "0123456789-,:") != strlen(optarg)) {
+		err("Invalid port specifier %s", optarg);
+		return -EINVAL;
+	}
+
+	p = optarg;
+	do {
+		int i, port;
+
+		port = strtol(p, &sep, 10);
+		if (sep == p)
+			break;
+
+		if (port < 0 || port > USHRT_MAX || errno)
+			goto bad;
+
+		/* -p 22
+		 *    ^ start_src	end_src == start_dst == end_dst == -1
+		 *
+		 * -p 22-25
+		 *    |  ^ end_src
+		 *     ` start_src	start_dst == end_dst == -1
+		 *
+		 * -p 80:8080
+		 *    |  ^ start_dst
+		 *     ` start_src	end_src == end_dst == -1
+		 *
+		 * -p 22-80:8022-8080
+		 *    |  |  |    ^ end_dst
+		 *    |  |   ` start_dst
+		 *    |   ` end_dst
+		 *     ` start_src
+		 */
+		switch (*sep) {
+		case '-':
+			if (start_src == -1) {		/* 22-... */
+				start_src = port;
+			} else {
+				if (!end_src)		/* 22:8022-8080 */
+					goto bad;
+				start_dst = port;	/* 22-80:8022-... */
+			}
+			break;
+		case ':':
+			if (start_src == -1)		/* 80:... */
+				start_src = end_src = port;
+			else if (end_src == -1)		/* 22-80:... */
+				end_src = port;
+			else				/* 22-80:8022:... */
+				goto bad;
+			break;
+		case ',':
+		case 0:
+			if (start_src == -1)		/* 80 */
+				start_src = end_src = port;
+			else if (end_src == -1)		/* 22-25 */
+				end_src = port;
+			else if (start_dst == -1)	/* 80:8080 */
+				start_dst = end_dst = port;
+			else if (end_dst == -1)		/* 22-80:8022-8080 */
+				end_dst = port;
+			else
+				goto bad;
+
+			if (start_src > end_src)	/* 80-22 */
+				goto bad;
+
+			if (start_dst > end_dst)	/* 22-80:8080:8022 */
+				goto bad;
+
+			if (end_dst != -1 &&
+			    end_dst - start_dst != end_src - start_src)
+				goto bad;		/* 22-81:8022:8080 */
+
+			for (i = start_src; i <= end_src; i++) {
+				if (bitmap_isset(map, i))
+					goto overlap;
+
+				bitmap_set(map, i);
+
+				if (start_dst == -1)	/* 22 or 22-80 */
+					continue;
+
+				/* 80:8080 or 22-80:8080:8080 */
+				remap(i, (in_port_t)(start_dst - start_src));
+			}
+
+			start_src = end_src = start_dst = end_dst = -1;
+			break;
+		}
+		p = sep + 1;
+	} while (*sep);
+
+	return 0;
+bad:
+	err("Invalid port specifier %s", optarg);
+	return -EINVAL;
+
+overlap:
+	err("Overlapping port specifier %s", optarg);
+	return -EINVAL;
+}
+
+/**
+ * struct nl_request - Netlink request filled and sent by get_routes()
+ * @nlh:	Netlink message header
+ * @rtm:	Routing Netlink message
+ */
+struct nl_request {
+	struct nlmsghdr nlh;
+	struct rtmsg rtm;
+};
+
+/**
+ * get_routes() - Get default route and fill in routable interface name
+ * @c:		Execution context
+ */
+static void get_routes(struct ctx *c)
+{
+	struct nl_request req = {
+		.nlh.nlmsg_type = RTM_GETROUTE,
+		.nlh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP | NLM_F_EXCL,
+		.nlh.nlmsg_len = sizeof(struct nl_request),
+		.nlh.nlmsg_seq = 1,
+		.rtm.rtm_family = AF_INET,
+		.rtm.rtm_table = RT_TABLE_MAIN,
+		.rtm.rtm_scope = RT_SCOPE_UNIVERSE,
+		.rtm.rtm_type = RTN_UNICAST,
+	};
+	struct sockaddr_nl addr = {
+		.nl_family = AF_NETLINK,
+	};
+	struct nlmsghdr *nlh;
+	int s, n, na, v4, v6;
+	char ifn[IFNAMSIZ];
+	struct rtattr *rta;
+	struct rtmsg *rtm;
+	char buf[BUFSIZ];
+
+	if (!c->v4 && !c->v6)
+		v4 = v6 = -1;
+	else
+		v6 = -!(v4 = -c->v4);
+
+	s = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
+	if (s < 0) {
+		perror("netlink socket");
+		goto out;
+	}
+
+	if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+		perror("netlink bind");
+		goto out;
+	}
+
+v6:
+	if (send(s, &req, sizeof(req), 0) < 0) {
+		perror("netlink send");
+		goto out;
+	}
+
+	n = recv(s, &buf, sizeof(buf), 0);
+	if (n < 0) {
+		perror("netlink recv");
+		goto out;
+	}
+
+	nlh = (struct nlmsghdr *)buf;
+	for ( ; NLMSG_OK(nlh, n); nlh = NLMSG_NEXT(nlh, n)) {
+		rtm = (struct rtmsg *)NLMSG_DATA(nlh);
+
+		if (rtm->rtm_dst_len ||
+		    (rtm->rtm_family != AF_INET && rtm->rtm_family != AF_INET6))
+			continue;
+
+		/* Filter on interface only if already given */
+		if (*c->ifn) {
+			*ifn = 0;
+			for (rta = (struct rtattr *)RTM_RTA(rtm),
+			     na = RTM_PAYLOAD(nlh);
+			     RTA_OK(rta, na); rta = RTA_NEXT(rta, na)) {
+				if (rta->rta_type != RTA_OIF)
+					continue;
+
+				if_indextoname(*(unsigned *)RTA_DATA(rta), ifn);
+				break;
+			}
+
+			if (strcmp(ifn, c->ifn))
+				goto next;
+		}
+
+		for (rta = (struct rtattr *)RTM_RTA(rtm), na = RTM_PAYLOAD(nlh);
+		     RTA_OK(rta, na); rta = RTA_NEXT(rta, na)) {
+			if (!*c->ifn && rta->rta_type == RTA_OIF)
+				if_indextoname(*(unsigned *)RTA_DATA(rta), ifn);
+
+			if (v4 && rta->rta_type == RTA_GATEWAY &&
+			    rtm->rtm_family == AF_INET) {
+				if (!c->gw4) {
+					memcpy(&c->gw4, RTA_DATA(rta),
+					       sizeof(c->gw4));
+				}
+				v4 = 1;
+			}
+
+			if (v6 && rta->rta_type == RTA_GATEWAY &&
+			    rtm->rtm_family == AF_INET6) {
+				if (IN6_IS_ADDR_UNSPECIFIED(&c->gw6)) {
+					memcpy(&c->gw6, RTA_DATA(rta),
+					       sizeof(c->gw6));
+				}
+				v6 = 1;
+			}
+		}
+
+next:
+		if (nlh->nlmsg_type == NLMSG_DONE)
+			break;
+	}
+
+	if (v6 == -1) {
+		req.rtm.rtm_family = AF_INET6;
+		req.nlh.nlmsg_seq++;
+		recv(s, &buf, sizeof(buf), 0);
+		v6--;
+		goto v6;
+	} else if (v6 < 0) {
+		v6 = 0;
+	}
+
+out:
+	close(s);
+
+	if ((v4 <= 0 && v6 <= 0) || (!*c->ifn && !*ifn)) {
+		err("No routing information");
+		exit(EXIT_FAILURE);
+	}
+
+	if (!*c->ifn)
+		strncpy(c->ifn, ifn, IFNAMSIZ);
+	c->v4 = v4;
+	c->v6 = v6;
+}
+
+/**
+ * get_addrs() - Fetch MAC, IP addresses, masks of external routable interface
+ * @c:		Execution context
+ */
+static void get_addrs(struct ctx *c)
+{
+	struct ifreq ifr = {
+		.ifr_addr.sa_family = AF_INET,
+	};
+	struct ifaddrs *ifaddr, *ifa;
+	int s, v4 = 0, v6 = 0;
+
+	if (getifaddrs(&ifaddr) == -1) {
+		perror("getifaddrs");
+		goto out;
+	}
+
+	if (c->addr4) {
+		c->addr4_seen = c->addr4;
+		v4 = 1;
+	}
+
+	if (!IN6_IS_ADDR_UNSPECIFIED(&c->addr6)) {
+		memcpy(&c->addr6_seen, &c->addr6, sizeof(c->addr6));
+		memcpy(&c->addr6_ll_seen, &c->addr6, sizeof(c->addr6));
+		v6 = 1;
+	}
+
+	/* Fill in any missing information */
+	for (ifa = ifaddr; ifa; ifa = ifa->ifa_next) {
+		struct sockaddr_in *in_addr;
+		struct sockaddr_in *in_mask;
+		struct sockaddr_in6 *in6_addr;
+
+		if (strcmp(ifa->ifa_name, c->ifn))
+			continue;
+
+		if (!ifa->ifa_addr)
+			continue;
+
+		in_addr = (struct sockaddr_in *)ifa->ifa_addr;
+		if (ifa->ifa_addr->sa_family == AF_INET && !c->addr4) {
+			c->addr4_seen = c->addr4 = in_addr->sin_addr.s_addr;
+			v4 = 1;
+		}
+
+		if (ifa->ifa_addr->sa_family == AF_INET && !c->mask4 &&
+		    in_addr->sin_addr.s_addr == c->addr4) {
+			in_mask = (struct sockaddr_in *)ifa->ifa_netmask;
+			c->mask4 = in_mask->sin_addr.s_addr;
+		}
+
+		if (ifa->ifa_addr->sa_family == AF_INET6) {
+			in6_addr = (struct sockaddr_in6 *)ifa->ifa_addr;
+			if (IN6_IS_ADDR_LINKLOCAL(&in6_addr->sin6_addr) &&
+			    IN6_IS_ADDR_UNSPECIFIED(&c->addr6_ll)) {
+				memcpy(&c->addr6_ll, &in6_addr->sin6_addr,
+				       sizeof(c->addr6_ll));
+			} else if (IN6_IS_ADDR_UNSPECIFIED(&c->addr6)) {
+				memcpy(&c->addr6, &in6_addr->sin6_addr,
+				       sizeof(c->addr6));
+				memcpy(&c->addr6_seen, &in6_addr->sin6_addr,
+				       sizeof(c->addr6_seen));
+				memcpy(&c->addr6_ll_seen, &in6_addr->sin6_addr,
+				       sizeof(c->addr6_seen));
+				v6 = 1;
+			}
+		}
+	}
+
+	freeifaddrs(ifaddr);
+
+	if (v4 < c->v4 || v6 < c->v6)
+		goto out;
+
+	if (v4 && !c->mask4) {
+		if (IN_CLASSA(ntohl(c->addr4)))
+			c->mask4 = htonl(IN_CLASSA_NET);
+		else if (IN_CLASSB(ntohl(c->addr4)))
+			c->mask4 = htonl(IN_CLASSB_NET);
+		else if (IN_CLASSC(ntohl(c->addr4)))
+			c->mask4 = htonl(IN_CLASSC_NET);
+		else
+			c->mask4 = 0xffffffff;
+	}
+
+	if (!memcmp(c->mac, ((uint8_t [ETH_ALEN]){ 0 }), ETH_ALEN)) {
+		s = socket(AF_INET, SOCK_DGRAM, 0);
+		if (s < 0) {
+			perror("socket SIOCGIFHWADDR");
+			goto out;
+		}
+
+		strncpy(ifr.ifr_name, c->ifn, IF_NAMESIZE);
+		if (ioctl(s, SIOCGIFHWADDR, &ifr) < 0) {
+			perror("SIOCGIFHWADDR");
+			goto out;
+		}
+
+		close(s);
+		memcpy(c->mac, ifr.ifr_hwaddr.sa_data, ETH_ALEN);
+	}
+
+	memset(&c->mac_guest, 0xff, sizeof(c->mac_guest));
+
+	return;
+out:
+	err("Couldn't get addresses for routable interface");
+	exit(EXIT_FAILURE);
+}
+
+/**
+ * get_dns() - Get nameserver addresses from local /etc/resolv.conf
+ * @c:		Execution context
+ */
+static void get_dns(struct ctx *c)
+{
+	int dns4_set, dns6_set, dnss_set, dns_set;
+	struct in6_addr *dns6 = &c->dns6[0];
+	struct fqdn *s = c->dns_search;
+	uint32_t *dns4 = &c->dns4[0];
+	char buf[BUFSIZ], *p, *end;
+	FILE *r;
+
+	dns4_set = !!*dns4;
+	dns6_set = !IN6_IS_ADDR_UNSPECIFIED(&dns6);
+	dnss_set = !!*s->n || c->no_dns_search;
+	dns_set = dns4_set || dns6_set || c->no_dns;
+
+	if (dns_set && dnss_set)
+		return;
+
+	r = fopen("/etc/resolv.conf", "r");
+	if (!r)
+		goto out;
+
+	while (fgets(buf, BUFSIZ, r)) {
+		if (!dns_set && strstr(buf, "nameserver ") == buf) {
+			p = strrchr(buf, ' ');
+			if (!p)
+				continue;
+
+			end = strpbrk(buf, "%\n");
+			if (end)
+				*end = 0;
+
+			if (dns4 - &c->dns4[0] < ARRAY_SIZE(c->dns4) &&
+			    inet_pton(AF_INET, p + 1, dns4))
+				dns4++;
+
+			if (dns6 - &c->dns6[0] < ARRAY_SIZE(c->dns6) &&
+			    inet_pton(AF_INET6, p + 1, dns6))
+				dns6++;
+		} else if (!dnss_set && strstr(buf, "search ") == buf &&
+			   s == c->dns_search) {
+			end = strpbrk(buf, "\n");
+			if (end)
+				*end = 0;
+
+			p = strtok(buf, " \t");
+			while ((p = strtok(NULL, " \t")) &&
+			       s - c->dns_search < ARRAY_SIZE(c->dns_search)) {
+				strncpy(s->n, p, sizeof(c->dns_search[0]));
+				s++;
+			}
+		}
+	}
+
+	fclose(r);
+
+out:
+	if (!dns_set && dns4 == c->dns4 && dns6 == c->dns6)
+		warn("Couldn't get any nameserver address");
+}
+
+/**
+ * usage() - Print usage and exit
+ * @name:	Executable name
+ */
+static void usage(const char *name)
+{
+	if (strstr(name, "pasta") || strstr(name, "passt4netns")) {
+		info("Usage: %s [OPTION]... [TARGET_PID]", name);
+		info("");
+		info("Without TARGET_PID, enter a user and network namespace,");
+		info("run the default shell and connect it via pasta.");
+	} else {
+		info("Usage: %s [OPTION]...", name);
+	}
+	info("");
+
+	info(   "  -d, --debug		Be verbose, don't run in background");
+	info(   "  -q, --quiet		Don't print informational messages");
+	info(   "  -f, --foreground	Don't run in background");
+	info(   "    default: run in background if started from a TTY");
+	info(   "  -e, --stderr		Log to stderr too");
+	info(   "    default: log to system logger only if started from a TTY");
+	info(   "  -h, --help		Display this help message and exit");
+
+	if (strstr(name, "pasta") || strstr(name, "passt4netns")) {
+		info(   "  -I, --ns-ifname NAME	namespace interface name");
+		info(   "    default: same interface name as external one");
+	} else {
+		info(   "  -s, --socket PATH	UNIX domain socket path");
+		info(   "    default: probe free path starting from "
+		     UNIX_SOCK_PATH, 1);
+	}
+
+	info(   "  -p, --pcap [FILE]	Log tap-facing traffic to pcap file");
+	info(   "    if FILE is not given, log to:");
+
+	if (strstr(name, "pasta") || strstr(name, "passt4netns"))
+		info("      pasta_ISO8601-TIMESTAMP_INSTANCE-NUMBER.pcap");
+	else
+		info("      passt_ISO8601-TIMESTAMP_INSTANCE-NUMBER.pcap");
+
+	info(   "  -m, --mtu MTU	Assign MTU via DHCP/NDP");
+	info(   "    default: no MTU assigned via DHCP/NDP options");
+	info(   "  -a, --address ADDR	Assign IPv4 or IPv6 address ADDR");
+	info(   "    can be specified zero to two times (for IPv4 and IPv6)");
+	info(   "    default: use addresses from interface with default route");
+	info(   "  -n, --netmask MASK	Assign IPv4 MASK, dot-decimal or bits");
+	info(   "    default: netmask from matching address on the host");
+	info(   "  -M, --mac-addr ADDR	Use source MAC address ADDR");
+	info(   "    default: MAC address from interface with default route");
+	info(   "  -g, --gateway ADDR	Pass IPv4 or IPv6 address as gateway");
+	info(   "    default: gateway from interface with default route");
+	info(   "  -i, --interface NAME	Interface for addresses and routes");
+	info(   "    default: interface with first default route");
+	info(   "  -D, --dns ADDR	Pass IPv4 or IPv6 address as DNS");
+	info(   "    can be specified multiple times");
+	info(   "    a single, empty option disables DNS information");
+	if (strstr(name, "pasta") || strstr(name, "passt4netns"))
+		info(   "    default: don't send any addresses");
+	else
+		info(   "    default: use addresses from /etc/resolv.conf");
+
+	info(   "  -S, --search LIST	Space-separated list, search domains");
+	info(   "    a single, empty option disables the DNS search list");
+	if (strstr(name, "pasta") || strstr(name, "passt4netns"))
+		info(   "    default: don't send any search list");
+	else
+		info(   "    default: use search list from /etc/resolv.conf");
+
+	info(   "  --no-tcp		Disable TCP protocol handler");
+	info(   "  --no-udp		Disable UDP protocol handler");
+	info(   "  --no-icmp		Disable ICMP/ICMPv6 protocol handler");
+	info(   "  --no-dhcp		Disable DHCP server");
+	info(   "  --no-ndp		Disable NDP responses");
+	info(   "  --no-dhcpv6		Disable DHCPv6 server");
+	info(   "  --no-ra		Disable router advertisements");
+	info(   "  -4, --ipv4-only	Enable IPv4 operation only");
+	info(   "  -6, --ipv6-only	Enable IPv6 operation only");
+
+	if (strstr(name, "pasta") || strstr(name, "passt4netns"))
+		goto pasta_ports;
+
+	info(   "  -t, --tcp-ports SPEC	TCP port forwarding to guest");
+	info(   "    can be specified multiple times");
+	info(   "    SPEC can be:");
+	info(   "      'none': don't forward any ports");
+	info(   "      'all': forward all unbound, non-ephemeral ports");
+	info(   "      a comma-separated of ports, optionally ranged with '-'");
+	info(   "        and optional target ports after ':'. Examples:");
+	info(   "        -t 22		Forward local port 22 to 22 on guest");
+	info(   "        -t 22:23	Forward local port 22 to 23 on guest");
+	info(   "        -t 22,25	Forward ports 22, 25 to ports 22, 25");
+	info(   "        -t 22-80  	Forward ports 22 to 80");
+	info(   "        -t 22-80:32-90	Forward ports 22 to 80 to");
+	info(   "			corresponding port numbers plus 10");
+	info(   "    default: none");
+	info(   "  -u, --udp-ports SPEC	UDP port forwarding to guest");
+	info(   "    SPEC is as described for TCP above");
+	info(   "    default: none");
+	info(   "    unless overridden, UDP ports with numbers corresponding");
+	info(   "      to forwarded TCP port numbers are forwarded too, and");
+	info(   "      IPv6 bound ports are also forwarded for IPv4");
+
+	exit(EXIT_FAILURE);
+
+pasta_ports:
+	info(   "  -t, --tcp-ports SPEC	TCP port forwarding to namespace");
+	info(   "    can be specified multiple times"); 
+	info(   "    SPEC can be:");
+	info(   "      'none': don't forward any ports");
+	info(   "      'auto': forward all ports currently bound in namespace");
+	info(   "      a comma-separated of ports, optionally ranged with '-'");
+	info(   "        and optional target ports after ':'. Examples:");
+	info(   "        -t 22	Forward local port 22 to port 22 in netns");
+	info(   "        -t 22:23	Forward local port 22 to port 23");
+	info(   "        -t 22,25	Forward ports 22, 25 to ports 22, 25");
+	info(   "        -t 22-80	Forward ports 22 to 80");
+	info(   "        -t 22-80:32-90	Forward ports 22 to 80 to");
+	info(   "			corresponding port numbers plus 10");
+	info(   "    default: auto");
+	info(   "    IPv6 bound ports are also forwarded for IPv4");
+	info(   "  -u, --udp-ports SPEC	UDP port forwarding to namespace");
+	info(   "    SPEC is as described for TCP above");
+	info(   "    default: auto");
+	info(   "    unless overridden, UDP ports with numbers corresponding");
+	info(   "      to forwarded TCP port numbers are forwarded too, and");
+	info(   "      IPv6 bound ports are also forwarded for IPv4");
+	info(   "  -T, --tcp-ns SPEC	TCP port forwarding to init namespace");
+	info(   "    SPEC is as described above");
+	info(   "    default: auto");
+	info(   "  -U, --udp-ns SPEC	UDP port forwarding to init namespace");
+	info(   "    SPEC is as described above");
+	info(   "    default: auto");
+
+	exit(EXIT_FAILURE);
+}
+
+void conf_print(struct ctx *c)
+{
+	char buf6[INET6_ADDRSTRLEN], buf4[INET_ADDRSTRLEN];
+	int i;
+
+	if (c->mode == MODE_PASTA) {
+		info("Outbound interface: %s, namespace interface: %s",
+		     c->ifn, c->pasta_ifn);
+	} else {
+		info("Outbound interface: %s", c->ifn);
+	}
+
+	if (c->v4) {
+		info("ARP:");
+		info("    address: %02x:%02x:%02x:%02x:%02x:%02x",
+		     c->mac[0], c->mac[1], c->mac[2],
+		     c->mac[3], c->mac[4], c->mac[5]);
+
+		if (!c->no_dhcp) {
+			info("DHCP:");
+			info("    assign: %s",
+			     inet_ntop(AF_INET, &c->addr4, buf4, sizeof(buf4)));
+			info("    mask: %s",
+			     inet_ntop(AF_INET, &c->mask4, buf4, sizeof(buf4)));
+			info("    router: %s",
+			     inet_ntop(AF_INET, &c->gw4,   buf4, sizeof(buf4)));
+		}
+	}
+
+	if (!c->no_dns && !(c->no_dhcp && c->no_ndp && c->no_dhcpv6)) {
+		for (i = 0; c->dns4[i]; i++) {
+			if (!i)
+				info("    DNS:");
+			inet_ntop(AF_INET, &c->dns4[i], buf4, sizeof(buf4));
+			info("        %s", buf4);
+		}
+	}
+
+	if (!c->no_dns_search && !(c->no_dhcp && c->no_ndp && c->no_dhcpv6)) {
+		for (i = 0; *c->dns_search[i].n; i++) {
+			if (!i)
+				info("        search:");
+			info("            %s", c->dns_search[i].n);
+		}
+	}
+
+	if (c->v6) {
+		if (!c->no_ndp && !c->no_dhcpv6)
+			info("NDP/DHCPv6:");
+		else if (!c->no_ndp)
+			info("DHCPv6:");
+		else if (!c->no_dhcpv6)
+			info("NDP:");
+		else
+			return;
+
+		info("    assign: %s",
+		     inet_ntop(AF_INET6, &c->addr6, buf6, sizeof(buf6)));
+		info("    router: %s",
+		     inet_ntop(AF_INET6, &c->gw6,   buf6, sizeof(buf6)));
+
+		for (i = 0; !IN6_IS_ADDR_UNSPECIFIED(&c->dns6[i]); i++) {
+			if (!i)
+				info("    DNS:");
+			inet_ntop(AF_INET6, &c->dns6[i], buf6, sizeof(buf6));
+			info("        %s", buf6);
+		}
+
+		for (i = 0; *c->dns_search[i].n; i++) {
+			if (!i)
+				info("        search:");
+			info("            %s", c->dns_search[i].n);
+		}
+	}
+}
+
+/**
+ * conf() - Process command-line arguments and set configuration
+ * @c:		Execution context
+ * @argc:	Argument count
+ * @argv:	Options, plus target PID for pasta mode
+ */
+void conf(struct ctx *c, int argc, char **argv)
+{
+	struct option options[] = {
+		{"debug",	no_argument,		NULL,		'd' },
+		{"quiet",	no_argument,		NULL,		1 },
+		{"foreground",	no_argument,		NULL,		'f' },
+		{"stderr",	no_argument,		&c->stderr,	1 },
+		{"help",	no_argument,		NULL,		'h' },
+		{"socket",	required_argument,	NULL,		's' },
+		{"ns-ifname",	required_argument,	NULL,		'I' },
+		{"pcap",	optional_argument,	NULL,		'p' },
+		{"mtu",		required_argument,	NULL,		'm' },
+		{"address",	required_argument,	NULL,		'a' },
+		{"netmask",	required_argument,	NULL,		'n' },
+		{"mac-addr",	required_argument,	NULL,		'M' },
+		{"gateway",	required_argument,	NULL,		'g' },
+		{"interface",	required_argument,	NULL,		'i' },
+		{"dns",		optional_argument,	NULL,		'D' },
+		{"search",	optional_argument,	NULL,		'S' },
+		{"no-tcp",	no_argument,		&c->no_tcp,	1 },
+		{"no-udp",	no_argument,		&c->no_udp,	1 },
+		{"no-icmp",	no_argument,		&c->no_icmp,	1 },
+		{"no-dhcp",	no_argument,		&c->no_dhcp,	1 },
+		{"no-dhcpv6",	no_argument,		&c->no_dhcpv6,	1 },
+		{"no-ndp",	no_argument,		&c->no_ndp,	1 },
+		{"no-ra",	no_argument,		&c->no_ra,	1 },
+		{"ipv4-only",	no_argument,		&c->v4,		'4' },
+		{"ipv6-only",	no_argument,		&c->v6,		'6' },
+		{"tcp-ports",	required_argument,	NULL,		't' },
+		{"udp-ports",	required_argument,	NULL,		'u' },
+		{"tcp-ns",	required_argument,	NULL,		'T' },
+		{"udp-ns",	required_argument,	NULL,		'U' },
+		{ 0 },
+	};
+	struct get_bound_ports_ns_arg ns_ports_arg = { .c = c };
+	enum conf_port_type tcp_tap = 0, tcp_init = 0;
+	enum conf_port_type udp_tap = 0, udp_init = 0;
+	struct fqdn *dnss = c->dns_search;
+	struct in6_addr *dns6 = c->dns6;
+	int name, ret, mask, b, i;
+	uint32_t *dns4 = c->dns4;
+
+	do {
+		enum conf_port_type *set;
+		const char *optstring;
+
+		if (c->mode == MODE_PASST)
+			optstring = "dqfehs:p::m:a:n:M:g:i:D::S::46t:u:";
+		else
+			optstring = "dqfehI:p::m:a:n:M:g:i:D::S::46t:u:T:U:";
+
+		name = getopt_long(argc, argv, optstring, options, NULL);
+
+		if ((name == 'p' || name == 'D' || name == 'S') && !optarg &&
+		    optind < argc && *argv[optind] && *argv[optind] != '-') {
+			if (c->mode == MODE_PASTA) {
+				char *endptr;
+
+				strtol(argv[optind], &endptr, 10);
+				if (*endptr)
+					optarg = argv[optind++];
+			} else {
+				optarg = argv[optind++];
+			}
+		}
+
+		switch (name) {
+		case -1:
+		case 0:
+			break;
+		case 'd':
+			if (c->debug) {
+				err("Multiple --debug options given");
+				usage(argv[0]);
+			}
+
+			if (c->quiet) {
+				err("Either --debug or --quiet");
+				usage(argv[0]);
+			}
+
+			c->debug = 1;
+			c->foreground = 1;
+			break;
+		case 'q':
+			if (c->quiet) {
+				err("Multiple --quiet options given");
+				usage(argv[0]);
+			}
+
+			if (c->debug) {
+				err("Either --debug or --quiet");
+				usage(argv[0]);
+			}
+
+			c->quiet = 1;
+			break;
+		case 'f':
+			if (c->foreground && !c->debug) {
+				err("Multiple --foreground options given");
+				usage(argv[0]);
+			}
+
+			c->foreground = 1;
+			break;
+		case '?':
+		case 'h':
+			usage(argv[0]);
+			break;
+		case 's':
+			if (*c->sock_path) {
+				err("Multiple --socket options given");
+				usage(argv[0]);
+			}
+
+			ret = snprintf(c->sock_path, sizeof(c->sock_path), "%s",
+				       optarg);
+			if (ret <= 0 || ret >= (int)sizeof(c->pcap)) {
+				err("Invalid socket path: %s", optarg);
+				usage(argv[0]);
+			}
+			break;
+		case 'I':
+			if (*c->pasta_ifn) {
+				err("Multiple --ns-ifname options given");
+				usage(argv[0]);
+			}
+
+			ret = snprintf(c->pasta_ifn, sizeof(c->pasta_ifn), "%s",
+				       optarg);
+			if (ret <= 0 || ret >= (int)sizeof(c->pasta_ifn)) {
+				err("Invalid interface name: %s", optarg);
+				usage(argv[0]);
+			}
+			break;
+		case 'p':
+			if (*c->pcap) {
+				err("Multiple --pcap options given");
+				usage(argv[0]);
+			}
+
+			if (!optarg) {
+				*c->pcap = 1;
+				break;
+			}
+
+			ret = snprintf(c->pcap, sizeof(c->pcap), "%s", optarg);
+			if (ret <= 0 || ret >= (int)sizeof(c->pcap)) {
+				err("Invalid pcap path: %s", optarg);
+				usage(argv[0]);
+			}
+			break;
+		case 'm':
+			if (c->mtu) {
+				err("Multiple --mtu options given");
+				usage(argv[0]);
+			}
+
+			errno = 0;
+			c->mtu = strtol(optarg, NULL, 0);
+			if (c->mtu < ETH_MIN_MTU || c->mtu > (int)ETH_MAX_MTU ||
+			    errno) {
+				err("Invalid MTU: %s", optarg);
+				usage(argv[0]);
+			}
+			break;
+		case 'a':
+			if (IN6_IS_ADDR_UNSPECIFIED(&c->addr6)		&&
+			    inet_pton(AF_INET6, optarg, &c->addr6)	&&
+			    !IN6_IS_ADDR_UNSPECIFIED(&c->addr6)		&&
+			    !IN6_IS_ADDR_LOOPBACK(&c->addr6)		&&
+			    !IN6_IS_ADDR_V4MAPPED(&c->addr6)		&&
+			    !IN6_IS_ADDR_V4COMPAT(&c->addr6)		&&
+			    !IN6_IS_ADDR_MULTICAST(&c->addr6))
+				break;
+
+			if (c->addr4 == INADDR_ANY			&&
+			    inet_pton(AF_INET, optarg, &c->addr4)	&&
+			    c->addr4 != INADDR_ANY			&&
+			    c->addr4 != INADDR_BROADCAST		&&
+			    c->addr4 != INADDR_LOOPBACK			&&
+			    !IN_MULTICAST(c->addr4))
+				break;
+
+			err("Invalid address: %s", optarg);
+			usage(argv[0]);
+			break;
+		case 'n':
+			if (inet_pton(AF_INET, optarg, &c->mask4))
+				break;
+
+			errno = 0;
+			mask = strtol(optarg, NULL, 0);
+			if (mask >= 0 && mask <= 32 && !errno) {
+				c->mask4 = htonl(0xffffffff << (32 - mask));
+				break;
+			}
+
+			err("Invalid netmask: %s", optarg);
+			usage(argv[0]);
+			break;
+		case 'M':
+			for (i = 0; i < ETH_ALEN; i++) {
+				errno = 0;
+				b = strtol(optarg + i * 3, NULL, 16);
+				if (b < 0 || b > UCHAR_MAX || errno) {
+					err("Invalid MAC address: %s", optarg);
+					usage(argv[0]);
+				}
+				c->mac[i] = b;
+			}
+			break;
+		case 'g':
+			if (IN6_IS_ADDR_UNSPECIFIED(&c->gw6)		&&
+			    inet_pton(AF_INET6, optarg, &c->gw6)	&&
+			    !IN6_IS_ADDR_UNSPECIFIED(&c->gw6)		&&
+			    !IN6_IS_ADDR_LOOPBACK(&c->gw6))
+				break;
+
+			if (c->gw4 == INADDR_ANY			&&
+			    inet_pton(AF_INET, optarg, &c->gw4)		&&
+			    c->gw4 != INADDR_ANY			&&
+			    c->gw4 != INADDR_BROADCAST			&&
+			    c->gw4 != INADDR_LOOPBACK)
+				break;
+
+			err("Invalid gateway address: %s", optarg);
+			usage(argv[0]);
+			break;
+		case 'i':
+			if (*c->ifn) {
+				err("Redundant interface: %s", optarg);
+				usage(argv[0]);
+			}
+
+			strncpy(c->ifn, optarg, IFNAMSIZ - 1);
+			break;
+		case 'D':
+			if (c->no_dns ||
+			    (!optarg && (dns4 - c->dns4 || dns6 - c->dns6))) {
+				err("Empty and non-empty DNS options given");
+				usage(argv[0]);
+			}
+
+			if (!optarg) {
+				c->no_dns = 1;
+				break;
+			}
+
+			if (dns4 - &c->dns4[0] < ARRAY_SIZE(c->dns4) &&
+			    inet_pton(AF_INET, optarg, dns4)) {
+				dns4++;
+				break;
+			}
+
+			if (dns6 - &c->dns6[0] < ARRAY_SIZE(c->dns6) &&
+			    inet_pton(AF_INET6, optarg, dns6)) {
+				dns6++;
+				break;
+			}
+
+			err("Cannot use DNS address %s", optarg);
+			usage(argv[0]);
+			break;
+		case 'S':
+			if (c->no_dns_search ||
+			    (!optarg && dnss != c->dns_search)) {
+				err("Empty and non-empty DNS search given");
+				usage(argv[0]);
+			}
+
+			if (!optarg) {
+				c->no_dns_search = 1;
+				break;
+			}
+
+			if (dnss - c->dns_search < ARRAY_SIZE(c->dns_search)) {
+				ret = snprintf(dnss->n, sizeof(*c->dns_search),
+					       "%s", optarg);
+				dnss++;
+
+				if (ret > 0 &&
+				    ret < (int)sizeof(*c->dns_search))
+					break;
+			}
+
+			err("Cannot use DNS search domain %s", optarg);
+			usage(argv[0]);
+			break;
+		case '4':
+			c->v4 = 1;
+			break;
+		case '6':
+			c->v6 = 1;
+			break;
+		case 't':
+		case 'u':
+		case 'T':
+		case 'U':
+			if (name == 't')
+				set = &tcp_tap;
+			else if (name == 'T')
+				set = &tcp_init;
+			else if (name == 'u')
+				set = &udp_tap;
+			else if (name == 'U')
+				set = &udp_init;
+
+			if (conf_ports(c, name, optarg, set))
+				usage(argv[0]);
+
+			break;
+		}
+	} while (name != -1);
+
+	if (c->mode == MODE_PASTA && optind + 1 == argc) {
+		c->pasta_pid = strtol(argv[optind], NULL, 0);
+		if (c->pasta_pid < 0 || errno)
+			usage(argv[0]);
+	} else if (optind != argc) {
+		usage(argv[0]);
+	}
+
+	if (c->v4 && c->v6) {
+		err("Options ipv4-only and ipv6-only are mutually exclusive");
+		usage(argv[0]);
+	}
+
+	if (c->v4 || c->v6) {
+		if (!c->v4)
+			c->no_dhcp = 1;
+
+		if (!c->v6) {
+			c->no_ndp = 1;
+			c->no_dhcpv6 = 1;
+		}
+	}
+
+	get_routes(c);
+	get_addrs(c);
+
+	if (c->mode == MODE_PASTA && dns4 == c->dns4 && dns6 == c->dns6)
+		c->no_dns = 1;
+	if (c->mode == MODE_PASTA && dnss == c->dns_search)
+		c->no_dns_search = 1;
+	get_dns(c);
+
+	if (!*c->pasta_ifn)
+		strncpy(c->pasta_ifn, c->ifn, IFNAMSIZ);
+
+	if (c->mode == MODE_PASTA) {
+		if (!tcp_tap || tcp_tap == PORT_AUTO) {
+			ns_ports_arg.proto = IPPROTO_TCP;
+			NS_CALL(get_bound_ports_ns, &ns_ports_arg);
+		}
+		if (!udp_tap || udp_tap == PORT_AUTO) {
+			ns_ports_arg.proto = IPPROTO_UDP;
+			NS_CALL(get_bound_ports_ns, &ns_ports_arg);
+		}
+		if (!tcp_init || tcp_init == PORT_AUTO)
+			get_bound_ports(c, IPPROTO_TCP);
+		if (!udp_init || udp_init == PORT_AUTO)
+			get_bound_ports(c, IPPROTO_UDP);
+	}
+
+	conf_print(c);
+}