add and document src_port_start and src_port_end

which currently only work for mode=dynamic-proxy

Author: alandekok

raddb/mods-available/radius

@@ -792,6 +792,34 @@ radius proxy {
 		#
 		src_ipaddr = *
 
+		#
+		#  src_port_start:: Start of source port range.
+		#
+		#  The outgoing proxy normally uses random source
+		#  ports.  When all of the RADIUS IDs are used for one
+		#  connection, it opens up another random source port.
+		#
+		#  However, it is sometimes useful to restrict the
+		#  range of source ports to known values.  The
+		#  `src_port_start` and `src_port_end` configuration
+		#  flags allow the port range to be controlled.  The
+		#  module will then restrict the source ports it is
+		#  using to be within this range.
+		#
+		#  When all ports in this range are used, the module
+		#  will not be able to open any more outgoing
+		#  connections.x
+		#
+		#  These two configuratiuon items can only be used for
+		#  UDP sockets.
+		#
+		src_port_start = 10000
+
+		#
+		#  src_port_end:: End of source port range.
+		#
+		src_port_end = 11000
+
 		#
 		#  `src_port` cannot be used.  If it is used here, the
 		#  module will refuse to start.  Instead, the module

src/modules/rlm_radius/bio.c

@@ -49,14 +49,13 @@ typedef struct {
 	rlm_radius_t const	*inst;		//!< our instance
 	fr_event_list_t		*el;	       	//!< Event list.
 	trunk_t			*trunk;	       	//!< trunk handler
-	fr_bio_fd_config_t	*fd_config;	//!< for threads or sockets
+	fr_bio_fd_config_t	fd_config;	//!< for threads or sockets
 	fr_bio_fd_info_t const	*fd_info;	//!< status of the FD.
 	fr_radius_ctx_t		radius_ctx;
 } bio_handle_ctx_t;
 
 typedef struct {
-	bio_handle_ctx_t	ctx;		//!< for copying to bio_handle_t
-
+	bio_handle_ctx_t	ctx;		//!< common struct for home servers and BIO handles
 
 	struct {
 		fr_bio_t *fd;			//!< writing
@@ -71,7 +70,7 @@ typedef struct bio_request_s bio_request_t;
  *
  */
 typedef struct {
-	bio_handle_ctx_t	ctx;		//! from thread or home server
+	bio_handle_ctx_t	ctx;		//!< common struct for home servers and BIO handles
 
 	int			fd;			//!< File descriptor.
 
@@ -140,8 +139,6 @@ struct bio_request_s {
 typedef struct {
 	bio_handle_ctx_t	ctx;		//!< for copying to bio_handle_t
 
-	fr_bio_fd_config_t	fd_config;	//!< fil descriptor configuration
-
 	fr_rb_expire_node_t	expire;
 } home_server_t;
 
@@ -747,7 +744,14 @@ static connection_state_t conn_init(void **h_out, connection_t *conn, void *uctx
 
 	MEM(h->tt = radius_track_alloc(h));
 
-	h->bio.fd = fr_bio_fd_alloc(h, h->ctx.fd_config, 0);
+	/*
+	 *	Limit the source port to the given range.
+	 */
+	if (h->ctx.inst->src_port_start) {
+		DEBUG("WARNING - src_port_start and src_port_end not currently supported.  A random source port will be chosen");
+	}
+
+	h->bio.fd = fr_bio_fd_alloc(h, &h->ctx.fd_config, 0);
 	if (!h->bio.fd) {
 		PERROR("%s - failed opening socket", h->ctx.module_name);
 	fail:
@@ -774,7 +778,7 @@ static connection_state_t conn_init(void **h_out, connection_t *conn, void *uctx
 	 *	way we don't need a memory BIO for UDP sockets, but we can still add a verification layer for
 	 *	UDP sockets?
 	 */
-	if (h->ctx.fd_config->socket_type == SOCK_STREAM) {
+	if (h->ctx.fd_config.socket_type == SOCK_STREAM) {
 		h->bio.mem = fr_bio_mem_alloc(h, 8192, 0, h->bio.fd);
 		if (!h->bio.mem) {
 			PERROR("%s - Failed allocating memory buffer - ", h->ctx.module_name);
@@ -1411,7 +1415,7 @@ static void mod_dup(request_t *request, bio_request_t *u)
 
 	h = talloc_get_type_abort(u->treq->tconn->conn->h, bio_handle_t);
 
-	if (h->ctx.fd_config->socket_type != SOCK_DGRAM) {
+	if (h->ctx.fd_config.socket_type != SOCK_DGRAM) {
 		RDEBUG("Using stream sockets - suppressing retransmission");
 		return;
 	}
@@ -1735,7 +1739,7 @@ static void mod_write(request_t *request, trunk_request_t *treq, bio_handle_t *h
 	/*
 	 *	We don't retransmit over TCP.
 	 */
-	if (h->ctx.fd_config->socket_type != SOCK_DGRAM) return;
+	if (h->ctx.fd_config.socket_type != SOCK_DGRAM) return;
 
 	/*
 	 *	If we only send one datagram packet, then don't bother saving it.
@@ -2427,7 +2431,6 @@ static const trunk_io_funcs_t	io_funcs = {
 	.request_cancel = request_cancel,
 };
 
-
 /** Instantiate thread data for the submodule.
  *
  */
@@ -2438,7 +2441,7 @@ static int mod_thread_instantiate(module_thread_inst_ctx_t const *mctx)
 
 	thread->ctx.el = mctx->el;
 	thread->ctx.inst = inst;
-	thread->ctx.fd_config = &inst->fd_config;
+	thread->ctx.fd_config = inst->fd_config;
 	thread->ctx.radius_ctx = inst->common_ctx;
 
 	if ((inst->mode != RLM_RADIUS_MODE_UNCONNECTED_REPLICATE) &&
@@ -2449,10 +2452,20 @@ static int mod_thread_instantiate(module_thread_inst_ctx_t const *mctx)
 		return 0;
 	}
 
+	/*
+	 *	If we have a port range, allocate the source IP based
+	 *	on the range start, plus the thread ID.  This means
+	 *	that we can avoid "hunt and peck" attempts to open up
+	 *	the source port.
+	 */
+	if (thread->ctx.inst->src_port_start) {
+		thread->ctx.fd_config.src_port = thread->ctx.inst->src_port_start + fr_schedule_worker_id();
+	}
+
 	/*
 	 *	Allocate the unconnected replication socket.
 	 */
-	thread->bio.fd = fr_bio_fd_alloc(thread, &thread->ctx.inst->fd_config, 0);
+	thread->bio.fd = fr_bio_fd_alloc(thread, &thread->ctx.fd_config, 0);
 	if (!thread->bio.fd) {
 		PERROR("%s - failed opening socket", inst->name);
 		return CONNECTION_STATE_FAILED;
@@ -2597,10 +2610,10 @@ static int8_t home_server_cmp(void const *one, void const *two)
 	home_server_t const *b = two;
 	int8_t rcode;
 
-	rcode = fr_ipaddr_cmp(&a->fd_config.dst_ipaddr, &b->fd_config.dst_ipaddr);
+	rcode = fr_ipaddr_cmp(&a->ctx.fd_config.dst_ipaddr, &b->ctx.fd_config.dst_ipaddr);
 	if (rcode != 0) return rcode;
 
-	return CMP(a->fd_config.dst_port, b->fd_config.dst_port);
+	return CMP(a->ctx.fd_config.dst_port, b->ctx.fd_config.dst_port);
 }
 
 static xlat_action_t xlat_sendto_resume(TALLOC_CTX *ctx, fr_dcursor_t *out,
@@ -2665,9 +2678,11 @@ static xlat_action_t xlat_radius_client(UNUSED TALLOC_CTX *ctx, UNUSED fr_dcurso
 	}
 
 	home = fr_rb_find(&thread->bio.expires.tree, &(home_server_t) {
-			.fd_config = (fr_bio_fd_config_t) {
-				.dst_ipaddr = ipaddr->vb_ip,
-				.dst_port = port->vb_uint16,
+			.ctx = {
+				.fd_config = (fr_bio_fd_config_t) {
+					.dst_ipaddr = ipaddr->vb_ip,
+					.dst_port = port->vb_uint16,
+				},
 			},
 		});
 	if (!home) {
@@ -2681,12 +2696,14 @@ static xlat_action_t xlat_radius_client(UNUSED TALLOC_CTX *ctx, UNUSED fr_dcurso
 			},
 		};
 
-		home->fd_config = inst->fd_config;
-		home->ctx.fd_config = &home->fd_config;
-
-		home->fd_config.type = FR_BIO_FD_CONNECTED;
-		home->fd_config.dst_ipaddr = ipaddr->vb_ip;
-		home->fd_config.dst_port = port->vb_uint32;
+		/*
+		 *	Copy the home server configuration from the root configuration.  Then update it with
+		 *	the needs of the home server.
+		 */
+		home->ctx.fd_config = inst->fd_config;
+		home->ctx.fd_config.type = FR_BIO_FD_CONNECTED;
+		home->ctx.fd_config.dst_ipaddr = ipaddr->vb_ip;
+		home->ctx.fd_config.dst_port = port->vb_uint32;
 
 		home->ctx.radius_ctx = (fr_radius_ctx_t) {
 			.secret = talloc_strdup(home, secret->vb_strvalue),

src/modules/rlm_radius/rlm_radius.c

@@ -103,6 +103,13 @@ static conf_parser_t const transport_config[] = {
 	CONF_PARSER_TERMINATOR
 };
 
+static conf_parser_t const transport_unconnected_config[] = {
+	{ FR_CONF_OFFSET("src_port_start", rlm_radius_t, src_port_start) },
+	{ FR_CONF_OFFSET("src_port_end", rlm_radius_t, src_port_end) },
+
+	CONF_PARSER_TERMINATOR
+};
+
 /*
  *	We only parse the pool options if we're connected.
  */
@@ -118,6 +125,14 @@ static conf_parser_t const connected_config[] = {
 	CONF_PARSER_TERMINATOR
 };
 
+static conf_parser_t const unconnected_config[] = {
+	{ FR_CONF_POINTER("udp", 0, CONF_FLAG_SUBSECTION | CONF_FLAG_OPTIONAL, NULL), .subcs = (void const *) transport_unconnected_config },
+
+	{ FR_CONF_POINTER("tcp", 0, CONF_FLAG_SUBSECTION | CONF_FLAG_OPTIONAL, NULL), .subcs = (void const *) transport_unconnected_config },
+
+	CONF_PARSER_TERMINATOR
+};
+
 /*
  *	We only parse the pool options if we're connected.
  */
@@ -126,6 +141,10 @@ static conf_parser_t const pool_config[] = {
 
 	{ FR_CONF_OFFSET_SUBSECTION("pool", 0, rlm_radius_t, trunk_conf, trunk_config ) },
 
+	{ FR_CONF_POINTER("udp", 0, CONF_FLAG_SUBSECTION | CONF_FLAG_OPTIONAL, NULL), .subcs = (void const *) transport_unconnected_config },
+
+	{ FR_CONF_POINTER("tcp", 0, CONF_FLAG_SUBSECTION | CONF_FLAG_OPTIONAL, NULL), .subcs = (void const *) transport_unconnected_config },
+
 	CONF_PARSER_TERMINATOR
 };
 
@@ -279,6 +298,7 @@ static int mode_parse(UNUSED TALLOC_CTX *ctx, void *out, void *parent,
 
 	case RLM_RADIUS_MODE_UNCONNECTED_REPLICATE:
 		inst->fd_config.type = FR_BIO_FD_UNCONNECTED;
+		if (cf_section_rules_push(cs, unconnected_config) < 0) return -1;
 		break;
 	}
 
@@ -656,23 +676,104 @@ static int mod_instantiate(module_inst_ctx_t const *mctx)
 	FR_INTEGER_BOUND_CHECK("max_packet_size", inst->max_packet_size, >=, 64);
 	FR_INTEGER_BOUND_CHECK("max_packet_size", inst->max_packet_size, <=, 65535);
 
-	if (inst->mode != RLM_RADIUS_MODE_UNCONNECTED_REPLICATE) {
+	/*
+	 *	Check invalid configurations.
+	 */
+	switch (inst->mode) {
+	default:
 		/*
-		 *	These limits are specific to RADIUS, and cannot be over-ridden
+		 *	Filenames are write-only, and cannot get response packets.
+		 */
+		if (inst->fd_config.filename) {
+			cf_log_err(conf, "Cannot set 'filename' here - it is only supported for 'mode=replicate'.");
+			return -1;
+		}
+
+		/*
+		 *	For normal proxying or originating client packets, we need to be able to open multiple
+		 *	source ports.  So the admin can't force a particular source port.
+		 */
+		if (inst->fd_config.src_port && (inst->mode != RLM_RADIUS_MODE_XLAT_PROXY)) {
+			cf_log_err(conf, "Cannot set 'src_port' when sending packets to a static destination");
+			return -1;
+		}
+
+		/*
+		 *	No src_port range, we don't need to check any other settings.
+		 */
+		if (!inst->src_port_start && !inst->src_port_end) break;
+
+		if (inst->fd_config.path) {
+			cf_log_err(conf, "Cannot set 'src_port_start' or 'src_port_end' for outgoing Unix sockets");
+			return -1;
+		}
+
+		/*
+		 *	We can only have one method of allocating source ports.
+		 */
+		if (inst->fd_config.src_port) {
+			cf_log_err(conf, "Cannot set 'src_port' and 'src_port_start' or 'src_port_end'");
+			return -1;
+		}
+
+		/*
+		 *	Cross-check src_port, src_port_start, and src_port_end.
+		 */
+		if (inst->src_port_start) {
+			if (!inst->src_port_end) {
+				cf_log_err(conf, "Range has 'src_port_start', but is missing 'src_port_end'");
+				return -1;
+			}
+
+			if (inst->src_port_start >= inst->src_port_end) {
+				cf_log_err(conf, "Range has invalid values for 'src_port_start' ... 'src_port_end'");
+				return -1;
+			}
+
+		} else if (inst->src_port_end) {
+			cf_log_err(conf, "Range has 'src_port_end', but is missing 'src_port_start'");
+			return -1;
+		}
+
+		/*
+		 *	Encorce limits per trunk, due to the 8-bit ID space.
 		 */
 		FR_INTEGER_BOUND_CHECK("trunk.per_connection_max", inst->trunk_conf.max_req_per_conn, >=, 2);
 		FR_INTEGER_BOUND_CHECK("trunk.per_connection_max", inst->trunk_conf.max_req_per_conn, <=, 255);
 		FR_INTEGER_BOUND_CHECK("trunk.per_connection_target", inst->trunk_conf.target_req_per_conn, <=, inst->trunk_conf.max_req_per_conn / 2);
-	}
+		break;
 
-	if ((inst->mode == RLM_RADIUS_MODE_UNCONNECTED_REPLICATE) ||
-	    (inst->mode == RLM_RADIUS_MODE_XLAT_PROXY)) {
-		if (inst->fd_config.src_port != 0) {
-			cf_log_err(conf, "Cannot set 'src_port' when using this 'mode'");
+	case RLM_RADIUS_MODE_UNCONNECTED_REPLICATE:
+		/*
+		 *	Replication to dynamic filenames or dynamic unix sockets isn't supported.
+		 */
+		if (inst->fd_config.filename || inst->fd_config.path) {
+			cf_log_err(conf, "Cannot set 'filename' or 'path' when using 'mode=unconnected-replicate'");
+			return -1;
+		}
+		FALL_THROUGH;
+
+	case RLM_RADIUS_MODE_REPLICATE:
+		/*
+		 *	We can force the source port, but then we have to set SO_REUSEPORT.
+		 */
+		inst->fd_config.reuse_port = (inst->fd_config.src_port != 0);
+
+		/*
+		 *	Files and unix sockets are OK.  The src_port can be set (or not), and that's fine.
+		 */
+		if (inst->src_port_start || inst->src_port_end) {
+			cf_log_err(conf, "Cannot set 'src_port_start' or 'src_port_end' when replicating packets");
 			return -1;
 		}
+		break;
 	}
 
+	/*
+	 *	We allow what may otherwise be conflicting configurations, because the BIO code will pick one
+	 *	path, and the conflicts won't affect anything else.  Only the src_port range is special.
+	 */
+
 	FR_TIME_DELTA_BOUND_CHECK("response_window", inst->zombie_period, >=, fr_time_delta_from_sec(1));
 	FR_TIME_DELTA_BOUND_CHECK("response_window", inst->zombie_period, <=, fr_time_delta_from_sec(120));
 

src/modules/rlm_radius/rlm_radius.h

@@ -64,6 +64,9 @@ struct rlm_radius_s {
 	uint32_t		max_packet_size;	//!< Maximum packet size.
 	uint16_t		max_send_coalesce;	//!< Maximum number of packets to coalesce into one mmsg call.
 
+	uint16_t		src_port_start;		//!< control the source port range for dynamic destinations
+	uint16_t		src_port_end;
+
 	fr_radius_ctx_t		common_ctx;
 
 	bool			replicate;		//!< Ignore responses.