construct/authd/providers/opm.cc

/* authd/providers/opm.c - small open proxy monitor
 * Copyright (c) 2016 Elizabeth Myers <elizabeth@interlinked.me>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice is present in all copies.
 *
 * 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 "authd.h"
#include "notice.h"
#include "provider.h"

using namespace ircd::defaults;

#define SELF_PID (opm_provider.id)

#define OPM_READSIZE 128

typedef enum protocol_t
{
	PROTO_NONE,
	PROTO_SOCKS4,
	PROTO_SOCKS5,
	PROTO_HTTP_CONNECT,
	PROTO_HTTPS_CONNECT,
} protocol_t;

/* Lookup data associated with auth client */
struct opm_lookup
{
	rb_dlink_list scans;	/* List of scans */
	bool in_progress;
};

struct opm_scan;
typedef void (*opm_callback_t)(struct opm_scan *);

/* A proxy scanner */
struct opm_proxy
{
	char note[16];
	protocol_t proto;
	uint16_t port;
	bool ssl;		/* Connect to proxy with SSL */
	bool ipv6;		/* Proxy supports IPv6 */

	opm_callback_t callback;

	rb_dlink_node node;
};

/* A listener for proxy replies */
struct opm_listener
{
	char ip[HOSTIPLEN];
	uint16_t port;
	struct rb_sockaddr_storage addr;
	rb_fde_t *F;
};

/* An individual proxy scan */
struct opm_scan
{
	struct auth_client *auth;
	rb_fde_t *F;			/* fd for scan */

	struct opm_proxy *proxy;	/* Associated proxy */
	struct opm_listener *listener;	/* Associated listener */

	rb_dlink_node node;
};

/* Proxies that we scan for */
static rb_dlink_list proxy_scanners;

static ACCB accept_opm;
static PF read_opm_reply;

static CNCB opm_connected;

static void opm_cancel(struct auth_client *auth);
static bool create_listener(const char *ip, uint16_t port);

static int opm_timeout = OPM_TIMEOUT_DEFAULT;
static bool opm_enable = false;

enum
{
	LISTEN_IPV4,
	LISTEN_IPV6,
	LISTEN_LAST,
};

/* IPv4 and IPv6 */
static struct opm_listener listeners[LISTEN_LAST];

static inline protocol_t
get_protocol_from_string(const char *str)
{
	if(strcasecmp(str, "socks4") == 0)
		return PROTO_SOCKS4;
	else if(strcasecmp(str, "socks5") == 0)
		return PROTO_SOCKS5;
	else if(strcasecmp(str, "httpconnect") == 0)
		return PROTO_HTTP_CONNECT;
	else if(strcasecmp(str, "httpsconnect") == 0)
		return PROTO_HTTPS_CONNECT;
	else
		return PROTO_NONE;
}

static inline struct opm_proxy *
find_proxy_scanner(protocol_t proto, uint16_t port)
{
	rb_dlink_node *ptr;

	RB_DLINK_FOREACH(ptr, proxy_scanners.head)
	{
		struct opm_proxy *proxy = (opm_proxy *)ptr->data;

		if(proxy->proto == proto && proxy->port == port)
			return proxy;
	}

	return NULL;
}

/* This is called when an open proxy connects to us */
static void
read_opm_reply(rb_fde_t *F, void *data)
{
	rb_dlink_node *ptr;
	struct auth_client *auth = (auth_client *)data;
	struct opm_lookup *lookup;
	char readbuf[OPM_READSIZE];
	ssize_t len;

	lrb_assert(auth != NULL);
	lookup = (opm_lookup *)get_provider_data(auth, SELF_PID);
	lrb_assert(lookup != NULL);

	if((len = rb_read(F, readbuf, sizeof(readbuf))) < 0 && rb_ignore_errno(errno))
	{
		rb_setselect(F, RB_SELECT_READ, read_opm_reply, auth);
		return;
	}
	else if(len <= 0)
	{
		/* Dead */
		rb_close(F);
		return;
	}

	RB_DLINK_FOREACH(ptr, proxy_scanners.head)
	{
		struct opm_proxy *proxy = (opm_proxy *)ptr->data;

		if(strncmp(proxy->note, readbuf, strlen(proxy->note)) == 0)
		{
			rb_dlink_node *ptr, *nptr;

			/* Cancel outstanding lookups */
			RB_DLINK_FOREACH_SAFE(ptr, nptr, lookup->scans.head)
			{
				struct opm_scan *scan = (opm_scan *)ptr->data;

				rb_close(scan->F);
				rb_free(scan);
			}

			/* No longer needed, client is going away */
			rb_free(lookup);

			reject_client(auth, SELF_PID, readbuf, "Open proxy detected");
			break;
		}
	}

	rb_close(F);
}

static void
accept_opm(rb_fde_t *F, int status, struct sockaddr *addr, rb_socklen_t len, void *data)
{
	struct auth_client *auth = NULL;
	struct opm_listener *listener = (opm_listener *)data;
	struct rb_sockaddr_storage localaddr;
	rb_socklen_t llen = sizeof(struct rb_sockaddr_storage);
	rb_dictionary_iter iter;

	if(status != 0 || listener == NULL)
	{
		rb_close(F);
		return;
	}

	if(getsockname(rb_get_fd(F), (struct sockaddr *)&localaddr, &llen))
	{
		/* This can happen if the client goes away after accept */
		rb_close(F);
		return;
	}

	/* Correlate connection with client(s) */
	void *elem;
	RB_DICTIONARY_FOREACH(elem, &iter, auth_clients)
	{
		auth = (auth_client *)elem;
		if(GET_SS_FAMILY(&auth->c_addr) != GET_SS_FAMILY(&localaddr))
			continue;

		/* Compare the addresses */
		switch(GET_SS_FAMILY(&localaddr))
		{
		case AF_INET:
			{
				struct sockaddr_in *s = (struct sockaddr_in *)&localaddr, *c = (struct sockaddr_in *)&auth->c_addr;

				if(s->sin_addr.s_addr == c->sin_addr.s_addr)
				{
					/* Match... check if it's real */
					rb_setselect(F, RB_SELECT_READ, read_opm_reply, auth);
					return;
				}
				break;
			}
#ifdef RB_IPV6
		case AF_INET6:
			{
				struct sockaddr_in6 *s = (struct sockaddr_in6 *)&localaddr, *c = (struct sockaddr_in6 *)&auth->c_addr;

				if(IN6_ARE_ADDR_EQUAL(&s->sin6_addr, &c->sin6_addr))
				{
					rb_setselect(F, RB_SELECT_READ, read_opm_reply, auth);
					return;
				}
				break;
			}
#endif
		default:
			warn_opers(L_CRIT, "OPM: unknown address type in listen function");
			exit(EX_PROVIDER_ERROR);
		}
	}

	/* We don't care about the socket if we get here */
	rb_close(F);
}

/* Scanners */

static void
opm_connected(rb_fde_t *F, int error, void *data)
{
	struct opm_scan *scan = (opm_scan *)data;
	struct opm_proxy *proxy = scan->proxy;
	struct auth_client *auth = scan->auth;
	struct opm_lookup *lookup = (opm_lookup *)get_provider_data(auth, SELF_PID);

	if(error || !opm_enable)
	{
		//notice_client(scan->auth->cid, "*** Scan not connected: %s", proxy->note);
		goto end;
	}

	switch(GET_SS_FAMILY(&auth->c_addr))
	{
	case AF_INET:
		if(listeners[LISTEN_IPV4].F == NULL)
			/* They cannot respond to us */
			goto end;

		break;
#ifdef RB_IPV6
	case AF_INET6:
		if(!proxy->ipv6)
			/* Welp, too bad */
			goto end;

		if(listeners[LISTEN_IPV6].F == NULL)
			/* They cannot respond to us */
			goto end;

		break;
#endif
	default:
		goto end;
	}

	proxy->callback(scan);

end:
	rb_close(scan->F);
	rb_dlinkDelete(&scan->node, &lookup->scans);
	rb_free(scan);
}

static void
socks4_connected(struct opm_scan *scan)
{
	struct auth_client *auth = scan->auth;
	struct opm_lookup *lookup = (opm_lookup *)get_provider_data(auth, SELF_PID);
	uint8_t sendbuf[9]; /* Size we're building */
	uint8_t *c = sendbuf;

	memcpy(c, "\x04\x01", 2); c += 2; /* Socks version 4, connect command */
	memcpy(c, &(((struct sockaddr_in *)&scan->listener->addr)->sin_port), 2); c += 2; /* Port */
	memcpy(c, &(((struct sockaddr_in *)&scan->listener->addr)->sin_addr.s_addr), 4); c += 4; /* Address */
	*c = '\x00'; /* No userid */

	/* Send header */
	if(rb_write(scan->F, sendbuf, sizeof(sendbuf)) < 0)
		return;

	/* Send note */
	if(rb_write(scan->F, scan->proxy->note, strlen(scan->proxy->note) + 1) < 0)
		return;
}

static void
socks5_connected(struct opm_scan *scan)
{
	struct auth_client *auth = scan->auth;
	struct opm_lookup *lookup = (opm_lookup *)get_provider_data(auth, SELF_PID);
	uint8_t sendbuf[25]; /* Size we're building */
	uint8_t *c = sendbuf;

	auth = scan->auth;
	lookup = (opm_lookup *)get_provider_data(auth, SELF_PID);

	/* Build the version header and socks request
	 * version header (3 bytes): version, number of auth methods, auth type (0 for none)
	 * connect req (3 bytes): version, command (1 = connect), reserved (0)
	 */
	memcpy(c, "\x05\x01\x00\x05\x01\x00", 6); c += 6;

	switch(GET_SS_FAMILY(&auth->c_addr))
	{
	case AF_INET:
		*(c++) = '\x01'; /* Address type (1 = IPv4) */
		memcpy(c, &(((struct sockaddr_in *)&scan->listener->addr)->sin_addr.s_addr), 4); c += 4; /* Address */
		memcpy(c, &(((struct sockaddr_in *)&scan->listener->addr)->sin_port), 2); c += 2; /* Port */
		break;
#ifdef RB_IPV6
	case AF_INET6:
		*(c++) = '\x04'; /* Address type (4 = IPv6) */
		memcpy(c, ((struct sockaddr_in6 *)&scan->listener->addr)->sin6_addr.s6_addr, 16); c += 16; /* Address */
		memcpy(c, &(((struct sockaddr_in6 *)&scan->listener->addr)->sin6_port), 2); c += 2; /* Port */
		break;
#endif
	default:
		return;
	}

	/* Send header */
	if(rb_write(scan->F, sendbuf, (size_t)(sendbuf - c)) <= 0)
		return;

	/* Now the note in a separate write */
	if(rb_write(scan->F, scan->proxy->note, strlen(scan->proxy->note) + 1) <= 0)
		return;
}

static void
http_connect_connected(struct opm_scan *scan)
{
	struct auth_client *auth = scan->auth;
	struct opm_lookup *lookup = (opm_lookup *)get_provider_data(auth, SELF_PID);
	char sendbuf[128]; /* A bit bigger than we need but better safe than sorry */
	char *c = sendbuf;

	/* Simple enough to build */
	snprintf(sendbuf, sizeof(sendbuf), "CONNECT %s:%hu HTTP/1.0\r\n\r\n", scan->listener->ip, scan->listener->port);

	/* Send request */
	if(rb_write(scan->F, sendbuf, strlen(sendbuf)) <= 0)
		return;

	/* Now the note in a separate write */
	if(rb_write(scan->F, scan->proxy->note, strlen(scan->proxy->note) + 1) <= 0)
		return;

	/* MiroTik needs this, and as a separate write */
	if(rb_write(scan->F, "\r\n", 2) <= 0)
		return;
}

/* Establish connections */
static inline void
establish_connection(struct auth_client *auth, struct opm_proxy *proxy)
{
	struct opm_lookup *lookup = (opm_lookup *)get_provider_data(auth, SELF_PID);
	struct opm_scan *scan = (opm_scan *)rb_malloc(sizeof(struct opm_scan));
	struct opm_listener *listener;
	struct rb_sockaddr_storage c_a, l_a;
	int opt = 1;

	lrb_assert(lookup != NULL);

#ifdef RB_IPV6
	if(GET_SS_FAMILY(&auth->c_addr) == AF_INET6)
	{
		if(proxy->proto == PROTO_SOCKS4)
		{
			/* SOCKS4 doesn't support IPv6 */
			rb_free(scan);
			return;
		}
		listener = &listeners[LISTEN_IPV6];
	}
	else
#endif
		listener = &listeners[LISTEN_IPV4];

	if(listener->F == NULL)
	{
		/* We can't respond */
		rb_free(scan);
		return;
	}

	c_a = auth->c_addr;	/* Client */
	l_a = listener->addr;	/* Listener (connect using its IP) */

	scan->auth = auth;
	scan->proxy = proxy;
	scan->listener = listener;
	if((scan->F = rb_socket(GET_SS_FAMILY(&auth->c_addr), SOCK_STREAM, 0, proxy->note)) == NULL)
	{
		warn_opers(L_WARN, "OPM: could not create OPM socket (proto %s): %s", proxy->note, strerror(errno));
		rb_free(scan);
		return;
	}

	/* Disable Nagle's algorithim - buffering could affect scans */
	(void)setsockopt(rb_get_fd(scan->F), IPPROTO_TCP, TCP_NODELAY, (char *)&opt, sizeof(opt));

	SET_SS_PORT(&l_a, 0);
	SET_SS_PORT(&c_a, htons(proxy->port));

	rb_dlinkAdd(scan, &scan->node, &lookup->scans);

	if(!proxy->ssl)
		rb_connect_tcp(scan->F,
				(struct sockaddr *)&c_a,
				(struct sockaddr *)&l_a,
				opm_connected, scan, opm_timeout);
	else
		rb_connect_tcp_ssl(scan->F,
				(struct sockaddr *)&c_a,
				(struct sockaddr *)&l_a,
				opm_connected, scan, opm_timeout);
}

static bool
create_listener(const char *ip, uint16_t port)
{
	struct auth_client *auth;
	struct opm_listener *listener;
	struct rb_sockaddr_storage addr;
	rb_dictionary_iter iter;
	rb_fde_t *F;
	int opt = 1;

	if(!rb_inet_pton_sock(ip, (struct sockaddr *)&addr))
	{
		warn_opers(L_CRIT, "OPM: got a bad listener: %s:%hu", ip, port);
		exit(EX_PROVIDER_ERROR);
	}

	SET_SS_PORT(&addr, htons(port));

#ifdef RB_IPV6
	if(GET_SS_FAMILY(&addr) == AF_INET6)
	{
		struct sockaddr_in6 *a1, *a2;

		listener = &listeners[LISTEN_IPV6];

		a1 = (struct sockaddr_in6 *)&addr;
		a2 = (struct sockaddr_in6 *)&listener->addr;

		if(IN6_ARE_ADDR_EQUAL(&a1->sin6_addr, &a2->sin6_addr) &&
			GET_SS_PORT(&addr) == GET_SS_PORT(&listener->addr) &&
			listener->F != NULL)
		{
			/* Listener already exists */
			return false;
		}
	}
	else
#endif
	{
		struct sockaddr_in *a1, *a2;

		listener = &listeners[LISTEN_IPV4];

		a1 = (struct sockaddr_in *)&addr;
		a2 = (struct sockaddr_in *)&listener->addr;

		if(a1->sin_addr.s_addr == a2->sin_addr.s_addr &&
			GET_SS_PORT(&addr) == GET_SS_PORT(&listener->addr) &&
			listener->F != NULL)
		{
			/* Listener already exists */
			return false;
		}
	}

	if((F = rb_socket(GET_SS_FAMILY(&addr), SOCK_STREAM, 0, "OPM listener socket")) == NULL)
	{
		/* This shouldn't fail, or we have big problems... */
		warn_opers(L_CRIT, "OPM: cannot create socket: %s", strerror(errno));
		exit(EX_PROVIDER_ERROR);
	}

	if(setsockopt(rb_get_fd(F), SOL_SOCKET, SO_REUSEADDR, (char *)&opt, sizeof(opt)))
	{
		/* This shouldn't fail either... */
		warn_opers(L_CRIT, "OPM: cannot set options on socket: %s", strerror(errno));
		exit(EX_PROVIDER_ERROR);
	}

	if(bind(rb_get_fd(F), (struct sockaddr *)&addr, GET_SS_LEN(&addr)))
	{
		/* Shit happens, let's not cripple authd over /this/ since it could be user error */
		warn_opers(L_WARN, "OPM: cannot bind on socket: %s", strerror(errno));
		rb_close(F);
		return false;
	}

	if(rb_listen(F, SOMAXCONN, false)) /* deferred accept could interfere with detection */
	{
		/* Again, could be user error */
		warn_opers(L_WARN, "OPM: cannot listen on socket: %s", strerror(errno));
		rb_close(F);
		return false;
	}

	/* From this point forward we assume we have a listener */

	if(listener->F != NULL)
		/* Close old listener */
		rb_close(listener->F);

	listener->F = F;

	/* Cancel clients that may be on old listener
	 * XXX - should rescan clients that need it
	 */
	void *elem;
	RB_DICTIONARY_FOREACH(elem, &iter, auth_clients)
	{
		auth = (auth_client *)elem;
		opm_cancel(auth);
		/* auth is now invalid as we have no reference */
	}

	/* Copy data */
	rb_strlcpy(listener->ip, ip, sizeof(listener->ip));
	listener->port = port;
	listener->addr = addr;

	opm_enable = true; /* Implicitly set this to true for now if we have a listener */
	rb_accept_tcp(listener->F, NULL, accept_opm, listener);
	return true;
}

static void
opm_scan(struct auth_client *auth)
{
	rb_dlink_node *ptr;
	struct opm_lookup *lookup;

	lrb_assert(auth != NULL);

	lookup = (opm_lookup *)get_provider_data(auth, SELF_PID);
	set_provider_timeout_relative(auth, SELF_PID, opm_timeout);

	lookup->in_progress = true;

	RB_DLINK_FOREACH(ptr, proxy_scanners.head)
	{
		struct opm_proxy *proxy = (opm_proxy *)ptr->data;
		//notice_client(auth->cid, "*** Scanning for proxy type %s", proxy->note);
		establish_connection(auth, proxy);
	}

	notice_client(auth->cid, "*** Scanning for open proxies...");
}

/* This is called every time a provider is completed as long as we are marked not done */
static void
opm_initiate(struct auth_client *auth, uint32_t provider)
{
	struct opm_lookup *lookup = (opm_lookup *)get_provider_data(auth, SELF_PID);
	uint32_t rdns_pid, ident_pid;

	lrb_assert(provider != SELF_PID);
	lrb_assert(!is_provider_done(auth, SELF_PID));
	lrb_assert(rb_dlink_list_length(&proxy_scanners) > 0);

	if(lookup == NULL || lookup->in_progress)
		/* Nothing to do */
		return;
	else if((!get_provider_id("rdns", &rdns_pid) || is_provider_done(auth, rdns_pid)) &&
		(!get_provider_id("ident", &ident_pid) || is_provider_done(auth, ident_pid)))
		/* Don't start until ident and rdns are finished (or not loaded) */
		return;
	else
		opm_scan(auth);
}

static bool
opm_start(struct auth_client *auth)
{
	uint32_t rdns_pid, ident_pid;

	lrb_assert(get_provider_data(auth, SELF_PID) == NULL);

	if(!opm_enable || rb_dlink_list_length(&proxy_scanners) == 0)
		/* Nothing to do... */
		return true;

	auth_client_ref(auth);

	set_provider_data(auth, SELF_PID, rb_malloc(sizeof(struct opm_lookup)));

	if((!get_provider_id("rdns", &rdns_pid) || is_provider_done(auth, rdns_pid)) &&
		(!get_provider_id("ident", &ident_pid) || is_provider_done(auth, ident_pid)))
	{
		/* Don't start until ident and rdns are finished (or not loaded) */
		opm_scan(auth);
	}

	set_provider_running(auth, SELF_PID);
	return true;
}

static void
opm_cancel(struct auth_client *auth)
{
	struct opm_lookup *lookup = (opm_lookup *)get_provider_data(auth, SELF_PID);

	if(lookup != NULL)
	{
		rb_dlink_node *ptr, *nptr;

		notice_client(auth->cid, "*** Did not detect open proxies");

		RB_DLINK_FOREACH_SAFE(ptr, nptr, lookup->scans.head)
		{
			struct opm_scan *scan = (struct opm_scan *)ptr->data;

			rb_close(scan->F);
			rb_free(scan);
		}

		rb_free(lookup);

		set_provider_data(auth, SELF_PID, NULL);
		set_provider_timeout_absolute(auth, SELF_PID, 0);
		provider_done(auth, SELF_PID);

		auth_client_unref(auth);
	}
}

static void
opm_destroy(void)
{
	struct auth_client *auth;
	rb_dictionary_iter iter;

	/* Nuke all opm lookups */
	void *elem;
	RB_DICTIONARY_FOREACH(elem, &iter, auth_clients)
	{
		auth = (auth_client *)elem;
		opm_cancel(auth);
		/* auth is now invalid as we have no reference */
	}
}


static void
add_conf_opm_timeout(const char *key, int parc, const char **parv)
{
	int timeout = atoi(parv[0]);

	if(timeout < 0)
	{
		warn_opers(L_CRIT, "opm: opm timeout < 0 (value: %d)", timeout);
		return;
	}

	opm_timeout = timeout;
}

static void
set_opm_enabled(const char *key, int parc, const char **parv)
{
	bool enable = (*parv[0] == '1');

	if(!enable)
	{
		if(listeners[LISTEN_IPV4].F != NULL || listeners[LISTEN_IPV6].F != NULL)
		{
			struct auth_client *auth;
			rb_dictionary_iter iter;

			/* Close the listening socket */
			if(listeners[LISTEN_IPV4].F != NULL)
				rb_close(listeners[LISTEN_IPV4].F);

			if(listeners[LISTEN_IPV6].F != NULL)
				rb_close(listeners[LISTEN_IPV6].F);

			listeners[LISTEN_IPV4].F = listeners[LISTEN_IPV6].F = NULL;

			void *elem;
			RB_DICTIONARY_FOREACH(elem, &iter, auth_clients)
			{
				auth = (auth_client *)elem;
				opm_cancel(auth);
				/* auth is now invalid as we have no reference */
			}
		}
	}
	else
	{
		if(listeners[LISTEN_IPV4].ip[0] != '\0' && listeners[LISTEN_IPV4].port != 0)
		{
			if(listeners[LISTEN_IPV4].F == NULL)
				/* Pre-configured IP/port, just re-establish */
				create_listener(listeners[LISTEN_IPV4].ip, listeners[LISTEN_IPV4].port);
		}

		if(listeners[LISTEN_IPV6].ip[0] != '\0' && listeners[LISTEN_IPV6].port != 0)
		{
			if(listeners[LISTEN_IPV6].F == NULL)
				/* Pre-configured IP/port, just re-establish */
				create_listener(listeners[LISTEN_IPV6].ip, listeners[LISTEN_IPV6].port);
		}
	}

	opm_enable = enable;
}

static void
set_opm_listener(const char *key, int parc, const char **parv)
{
	const char *ip = parv[0];
	int iport = atoi(parv[1]);

	if(iport > 65535 || iport <= 0)
	{
		warn_opers(L_CRIT, "OPM: got a bad listener: %s:%s", parv[0], parv[1]);
		exit(EX_PROVIDER_ERROR);
	}

	create_listener(ip, (uint16_t)iport);
}

static void
create_opm_scanner(const char *key, int parc, const char **parv)
{
	int iport = atoi(parv[1]);
	struct opm_proxy *proxy = (opm_proxy *)rb_malloc(sizeof(struct opm_proxy));

	if(iport <= 0 || iport > 65535)
	{
		warn_opers(L_CRIT, "OPM: got a bad scanner: %s (port %s)", parv[0], parv[1]);
		exit(EX_PROVIDER_ERROR);
	}

	proxy->port = (uint16_t)iport;

	switch((proxy->proto = get_protocol_from_string(parv[0])))
	{
	case PROTO_SOCKS4:
		snprintf(proxy->note, sizeof(proxy->note), "socks4:%hu", proxy->port);
		proxy->ssl = false;
		proxy->callback = socks4_connected;
		break;
	case PROTO_SOCKS5:
		snprintf(proxy->note, sizeof(proxy->note), "socks5:%hu", proxy->port);
		proxy->ssl = false;
		proxy->callback = socks5_connected;
		break;
	case PROTO_HTTP_CONNECT:
		snprintf(proxy->note, sizeof(proxy->note), "httpconnect:%hu", proxy->port);
		proxy->ssl = false;
		proxy->callback = http_connect_connected;
		break;
	case PROTO_HTTPS_CONNECT:
		snprintf(proxy->note, sizeof(proxy->note), "httpsconnect:%hu", proxy->port);
		proxy->callback = http_connect_connected;
		proxy->ssl = true;
		break;
	default:
		warn_opers(L_CRIT, "OPM: got an unknown proxy type: %s (port %hu)", parv[0], proxy->port);
		exit(EX_PROVIDER_ERROR);
	}

	if(find_proxy_scanner(proxy->proto, proxy->port) != NULL)
	{
		warn_opers(L_CRIT, "OPM: got a duplicate scanner: %s (port %hu)", parv[0], proxy->port);
		exit(EX_PROVIDER_ERROR);
	}

	rb_dlinkAdd(proxy, &proxy->node, &proxy_scanners);
}

static void
delete_opm_scanner(const char *key, int parc, const char **parv)
{
	struct auth_client *auth;
	struct opm_proxy *proxy;
	protocol_t proto = get_protocol_from_string(parv[0]);
	int iport = atoi(parv[1]);
	rb_dictionary_iter iter;

	if(iport <= 0 || iport > 65535)
	{
		warn_opers(L_CRIT, "OPM: got a bad scanner to delete: %s (port %s)", parv[0], parv[1]);
		exit(EX_PROVIDER_ERROR);
	}

	if(proto == PROTO_NONE)
	{
		warn_opers(L_CRIT, "OPM: got an unknown proxy type to delete: %s (port %d)", parv[0], iport);
		exit(EX_PROVIDER_ERROR);
	}

	if((proxy = find_proxy_scanner(proto, (uint16_t)iport)) == NULL)
	{
		warn_opers(L_CRIT, "OPM: cannot find proxy to delete: %s (port %d)", parv[0], iport);
		exit(EX_PROVIDER_ERROR);
	}

	/* Abort remaining clients on this scanner */
	void *elem;
	RB_DICTIONARY_FOREACH(elem, &iter, auth_clients)
	{
		rb_dlink_node *ptr;
		auth = (auth_client *)elem;
		struct opm_lookup *lookup = (opm_lookup *)get_provider_data(auth, SELF_PID);

		if(lookup == NULL)
			continue;

		auth_client_ref(auth);

		RB_DLINK_FOREACH(ptr, lookup->scans.head)
		{
			struct opm_scan *scan = (struct opm_scan *)ptr->data;

			if(scan->proxy->port == proxy->port && scan->proxy->proto == proxy->proto)
			{
				/* Match */
				rb_dlinkDelete(&scan->node, &lookup->scans);
				rb_free(scan);

				if(rb_dlink_list_length(&lookup->scans) == 0)
					opm_cancel(auth);

				break;
			}
		}

		auth_client_unref(auth);
	}

	rb_dlinkDelete(&proxy->node, &proxy_scanners);
	rb_free(proxy);

	if(rb_dlink_list_length(&proxy_scanners) == 0)
		opm_enable = false;
}

static void
delete_opm_scanner_all(const char *key, int parc, const char **parv)
{
	struct auth_client *auth;
	rb_dlink_node *ptr, *nptr;
	rb_dictionary_iter iter;

	RB_DLINK_FOREACH_SAFE(ptr, nptr, proxy_scanners.head)
	{
		rb_free(ptr->data);
		rb_dlinkDelete(ptr, &proxy_scanners);
	}

	void *elem;
	RB_DICTIONARY_FOREACH(elem, &iter, auth_clients)
	{
		auth = (auth_client *)elem;
		opm_cancel(auth);
		/* auth is now invalid as we have no reference */
	}

	opm_enable = false;
}

static void
delete_opm_listener_all(const char *key, int parc, const char **parv)
{
	if(listeners[LISTEN_IPV4].F != NULL)
		rb_close(listeners[LISTEN_IPV4].F);

#ifdef RB_IPV6
	if(listeners[LISTEN_IPV6].F != NULL)
		rb_close(listeners[LISTEN_IPV6].F);
#endif

	memset(&listeners, 0, sizeof(listeners));
}


struct auth_opts_handler opm_options[] =
{
	{ "opm_timeout", 1, add_conf_opm_timeout },
	{ "opm_enabled", 1, set_opm_enabled },
	{ "opm_listener", 2, set_opm_listener },
	{ "opm_listener_del_all", 0, delete_opm_listener_all },
	{ "opm_scanner", 2, create_opm_scanner },
	{ "opm_scanner_del", 2, delete_opm_scanner },
	{ "opm_scanner_del_all", 0, delete_opm_scanner_all },
	{ NULL, 0, NULL },
};

struct auth_provider opm_provider =
[]{
	auth_provider ap {0};
	ap.name = "opm";
	ap.letter = 'O';
	ap.destroy = opm_destroy;
	ap.start = opm_start;
	ap.cancel = opm_cancel;
	ap.timeout = opm_cancel;
	ap.completed = opm_initiate;
	ap.opt_handlers = opm_options;
	return ap;
}();