Merge net branch into master

Main changes: - HTTP sample application Basic Auth support - DNS parsing fixes - SLIP MAC address can be set from Kconfig - SLIP driver memory corruption fix - IPv6 neighbor unreachability detection (NUD) fixes - ICMPv6 fixes - Compiler warning fixes - IEEE 802.15.4 CC2520 MAC address can be set from Kconfig - Multiple k_delayed_work_init() call fixes in network stack - 6lo (IPv6 header compression) fix - Atmel SAM family GMAC ethernet driver update - RPL protocol header fixes - mbedtls CoAP fixes - Management API supports now synchronous event waiting - RX and TX thread startup fix - net_buf leak fixes in error cases ---------------------------------------------------------------- Flavio Santes (6): samples/http: Match header field ctr with Kconfig variable net/http: Move some statements to the right place samples/net/http: Add the HTTP Basic Authentication routine net/dns: Fix wrong name in DNS answer type routine net/dns: Fix DNS answer RR computation tests/net/dns: Add routines to evaluate DNS responses Inaky Perez-Gonzalez (1): drivers: slip: Allow specifying the MAC address from config file Jukka Rissanen (32): net: ipv6: Add debug function to convert nbr state to string net: ipv6: Print IPv6 neighbor state changes net: ipv6: Send NS when neighbor is added net: ipv6: Return the prefix lifetime in seconds net: shell: Print more detailed neighbor information net: ipv6: Wrong timer was used when reachability timer expired net: ipv6: Add more debugging to reachability timer net: ipv6: Properly enter DELAY state in NUD net: utils: Byte to hex converter had wrong prototype samples: net: zperf: Fix compiler warnings net: tests: nbuf: Fix compiler warnings net: shell: Add cmd to remove IPv6 neighbor from cache net: shell: Pretty print the neighbor cache info net: tests: Fix the default MAC address net: Synchronize TX and RX threads startup net: Ignore everything in RX if interface is not up net: ipv6: Use net_nbuf_unref() to get better debug prints net: ipv6: Make sure there is data to be sent net: ipv6: Clear pending buf if NS cannot be sent net: ipv6: Enhance debug print when handling pending packet drivers: slip: Use always the initialized network interface net: Print error if buf or interface are NULL when receiving pkt net: ipv6: Make config options more fine grained drivers: slip: Fix memory corruption when receiving packet net: ipv6: Cancel the prefix timer before setting it again net: ipv6: Prefix length was incorrectly set net: icmp: Gracefully timeout net_buf get in RX path net: icmp: Update ICMP statistics for every ICMP packet net: icmp: Fix return values of ICMP error send function net: tcp: Print TCP trace in one line samples: net: coaps_client: Fix the parameters when setting callbacks drivers: ieee802154: cc2520: User can set the MAC address Luiz Augusto von Dentz (5): net: if: Don't check NET_IF_UP in net_if_prepare_events net: bt: Fix warnings when debug is enabled net: if: Make sure k_delayed_work_init is only called once net: ipv6: Make sure k_delayed_work_init is only called once net: rpl: Make sure k_delayed_work_init is only called once Michael Scott (2): net: 6lo: Fix typo in compress bit calculation net/http: let HTTP_SERVER, HTTP_CLIENT and HTTP_PARSER select HTTP Paul Sokolovsky (2): net: connection: Move proto2str() to utils.c, rename to net_proto2str() net: context: For bind debug logging, include context protocol. Piotr Mienkowski (1): drivers: Update Atmel SAM family GMAC Ethernet driver Ravi kumar Veeramally (9): net: core: Fix IPv6 RPL extension parsing net: rpl: Add RPL header revert utility net: ipv6: Fix handling of RA 6CO options net: icmpv6: Add support for HBH and RPL option handling net: context: Fix setting of appdata ptr and length net: rpl: Fix compilation warnings about format specifier net: rpl: Add API to access default rpl instance net: Modify IPv4/6 packet finalize API's net: samples: leds_demo: Fix memory leak Sergio Rodriguez (2): samples: mbedtls coap: Fixing entropy source samples: mbedTLS coap: Cleaning prj.conf for QEMU Tomasz Bursztyka (7): net/ieee802154: Add missing line breaks in the shell module net/ieee802154: Fix net mgmt request to get core settings net/mgmt: Add a function to wait on a event synchronously net/mgmt: Add a network interface based synchronous event listener tests/net/mgmt: Add 2 unit tests around synchronous event listeners. net/mgmt: Remove a useless k_sem_init() and use K_SEM_DEFINE instead net/mgmt: Remove the list node before unlocking the semaphore .known-issues/doc/networking.conf | 12 + drivers/ethernet/Kconfig.sam_gmac | 16 +- drivers/ethernet/eth_sam_gmac.c | 82 +++++- drivers/ethernet/eth_sam_gmac_priv.h | 6 +- drivers/ieee802154/Kconfig.cc2520 | 37 +++ drivers/ieee802154/ieee802154_cc2520.c | 15 +- drivers/slip/Kconfig | 11 + drivers/slip/slip.c | 64 ++++- include/net/net_mgmt.h | 92 ++++++- samples/net/coaps_client/src/coaps_client.c | 17 +- samples/net/coaps_server/prj_qemu_x86.conf | 5 +- samples/net/coaps_server/src/coaps_server.c | 13 +- samples/net/echo_server/prj_sam_e70_xplained.conf | 3 - samples/net/http_client/prj_frdm_k64f.conf | 1 - samples/net/http_client/prj_qemu_x86.conf | 1 - samples/net/http_server/README.rst | 21 ++ samples/net/http_server/prj_frdm_k64f.conf | 1 - samples/net/http_server/prj_qemu_x86.conf | 1 - samples/net/http_server/src/config.h | 9 + samples/net/http_server/src/http_server.c | 19 +- samples/net/http_server/src/http_server.h | 2 + samples/net/http_server/src/http_types.h | 4 +- samples/net/http_server/src/http_write_utils.c | 18 ++ samples/net/http_server/src/http_write_utils.h | 4 + samples/net/http_server/src/main.c | 1 + samples/net/leds_demo/src/leds-demo.c | 36 ++- samples/net/zperf/src/zperf_udp_receiver.c | 2 +- samples/net/zperf/src/zperf_udp_uploader.c | 24 +- subsys/net/ip/6lo.c | 2 +- subsys/net/ip/Kconfig.ipv6 | 10 +- subsys/net/ip/connection.c | 24 +- subsys/net/ip/icmpv4.c | 28 +- subsys/net/ip/icmpv6.c | 78 ++++-- subsys/net/ip/ipv4.c | 8 +- subsys/net/ip/ipv4.h | 10 +- subsys/net/ip/ipv6.c | 305 +++++++++++++++------- subsys/net/ip/ipv6.h | 65 +++-- subsys/net/ip/l2/bluetooth.c | 8 +- subsys/net/ip/l2/ieee802154/ieee802154_mgmt.c | 2 +- subsys/net/ip/l2/ieee802154/ieee802154_shell.c | 8 +- subsys/net/ip/net_context.c | 98 +++---- subsys/net/ip/net_core.c | 30 ++- subsys/net/ip/net_if.c | 189 ++++++++------ subsys/net/ip/net_mgmt.c | 108 +++++++- subsys/net/ip/net_private.h | 6 +- subsys/net/ip/net_shell.c | 68 +++-- subsys/net/ip/rpl.c | 223 +++++++++++----- subsys/net/ip/rpl.h | 30 ++- subsys/net/ip/tcp.c | 85 +++--- subsys/net/ip/utils.c | 18 ++ subsys/net/lib/dns/dns_pack.c | 4 +- subsys/net/lib/dns/dns_pack.h | 11 +- subsys/net/lib/http/Kconfig | 6 +- subsys/net/lib/http/http_server.c | 10 +- tests/net/6lo/src/main.c | 4 +- tests/net/arp/src/main.c | 10 +- tests/net/context/prj.conf | 3 + tests/net/context/src/main.c | 10 +- tests/net/dhcpv4/prj.conf | 1 + tests/net/dhcpv4/src/main.c | 24 +- tests/net/iface/src/main.c | 10 +- tests/net/ip-addr/src/main.c | 10 +- tests/net/ipv6/src/main.c | 10 +- tests/net/lib/dns_packet/src/dns_packet.c | 266 ++++++++++++++++++- tests/net/lib/http_header_fields/prj.conf | 1 - tests/net/mgmt/src/mgmt.c | 57 +++- tests/net/mld/src/main.c | 12 +- tests/net/nbuf/src/main.c | 28 +- tests/net/route/src/main.c | 14 +- tests/net/rpl/src/main.c | 10 +- tests/net/tcp/src/main.c | 10 +- tests/net/udp/src/main.c | 10 +- 72 files changed, 1780 insertions(+), 661 deletions(-) Change-Id: I6f911be46eec8ae760fc5077d473aca6c47e91ae Signed-off-by: Jukka Rissanen <[email protected]>
FantomJAC · Mar 17, 2017 · cfaf64c · cfaf64c
2 parents efc68b4 + 7aa5ae1
commit cfaf64c
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diff --git a/.known-issues/doc/networking.conf b/.known-issues/doc/networking.conf
@@ -47,3 +47,15 @@
 ^(?P=filename):(?P=lineno): WARNING: Invalid definition: Expected end of definition. \[error at [0-9]+]
 ^.*dns_context.address
 ^[- \t]*\^
+#
+# include/net/net_mgmt.h
+#
+^(?P<filename>[-._/\w]+/doc/api/networking.rst):(?P<lineno>[0-9]+): WARNING: Invalid definition: Expected identifier in nested name. \[error at [0-9]+]
+^[ \t]*
+^[ \t]*\^
+^(?P=filename):(?P=lineno): WARNING: Invalid definition: Expected identifier in nested name. \[error at [0-9]+]
+^[ \t]*
+^[ \t]*\^
+^(?P=filename):(?P=lineno): WARNING: Invalid definition: Expected end of definition. \[error at [0-9]+]
+^.*net_mgmt_event_callback.__unnamed__
+^[- \t]*\^
diff --git a/drivers/ethernet/Kconfig.sam_gmac b/drivers/ethernet/Kconfig.sam_gmac
@@ -20,20 +20,20 @@ config ETH_SAM_GMAC_NAME
 	  Device name allows user to obtain a handle to the device object
 	  required by all driver API functions. Device name has to be unique.
 
-config ETH_SAM_GMAC_NBUF_DATA_COUNT
-	int "Network data buffers pre-allocated by the SAM ETH driver"
-	default 12
+config ETH_SAM_GMAC_NBUF_RX_DATA_COUNT
+	int "Network RX data buffers pre-allocated by the SAM ETH driver"
+	default 18
 	help
 	  Number of network data buffers that will be permanently allocated by the
 	  Ethernet driver. These data buffers are used in receive path. They are
 	  pre-alocated by the driver and made available to the GMAC module to be
 	  filled in with incoming data. Their number has to be large enough to fit
 	  at least one complete Ethernet frame. SAM ETH driver will always allocate
-	  that amount of buffers for itself thus reducing the NET_NBUF_DATA_COUNT
-	  which is a total amount of data buffers used by the whole networking
-	  stack. One has to ensure that NET_NBUF_DATA_COUNT is large enough to fit
-	  at least two ethernet frames: one being received by the GMAC module and
-	  the other being processed by the higer layer networking stack.
+	  that amount of buffers for itself thus reducing the NET_NBUF_RX_DATA_COUNT
+	  which is a total amount of RX data buffers used by the whole networking
+	  stack. One has to ensure that NET_NBUF_RX_DATA_COUNT is large enough to
+	  fit at least two ethernet frames: one being received by the GMAC module
+	  and the other being processed by the higer layer networking stack.
 
 config ETH_SAM_GMAC_IRQ_PRI
 	int "Interrupt priority"

diff --git a/drivers/ethernet/eth_sam_gmac.c b/drivers/ethernet/eth_sam_gmac.c
@@ -38,21 +38,24 @@
  * Verify Kconfig configuration
  */
 
-#if CONFIG_NET_NBUF_RX_DATA_COUNT <= CONFIG_ETH_SAM_GMAC_NBUF_DATA_COUNT
-#error CONFIG_NET_NBUF_RX_DATA_COUNT has to be larger than \
-	CONFIG_ETH_SAM_GMAC_NBUF_DATA_COUNT
+#if CONFIG_NET_NBUF_DATA_SIZE * CONFIG_ETH_SAM_GMAC_NBUF_RX_DATA_COUNT \
+	< GMAC_FRAME_SIZE_MAX
+#error CONFIG_NET_NBUF_DATA_SIZE * CONFIG_ETH_SAM_GMAC_NBUF_RX_DATA_COUNT is \
+	not large enough to hold a full frame
 #endif
 
-#if CONFIG_NET_NBUF_DATA_SIZE * CONFIG_ETH_SAM_GMAC_NBUF_DATA_COUNT \
-	< GMAC_FRAME_SIZE_MAX
-#error CONFIG_NET_NBUF_DATA_SIZE * CONFIG_ETH_SAM_GMAC_NBUF_DATA_COUNT is not \
-	large enough to hold a full frame
+#if CONFIG_NET_NBUF_DATA_SIZE * (CONFIG_NET_NBUF_RX_DATA_COUNT - \
+	CONFIG_ETH_SAM_GMAC_NBUF_RX_DATA_COUNT) < GMAC_FRAME_SIZE_MAX
+#error Remaining free RX data buffers (CONFIG_NET_NBUF_RX_DATA_COUNT -
+	CONFIG_ETH_SAM_GMAC_NBUF_RX_DATA_COUNT) * CONFIG_NET_NBUF_DATA_SIZE
+	are not large enough to hold a full frame
 #endif
 
-#if CONFIG_NET_NBUF_DATA_SIZE * CONFIG_NET_NBUF_RX_DATA_COUNT \
-	< 2 * GMAC_FRAME_SIZE_MAX
-#error CONFIG_NET_NBUF_DATA_SIZE * CONFIG_NET_NBUF_RX_DATA_COUNT is not large\
-	enough to hold two full frames
+#if CONFIG_NET_NBUF_DATA_SIZE * CONFIG_NET_NBUF_TX_DATA_COUNT \
+	< GMAC_FRAME_SIZE_MAX
+#pragma message "Maximum frame size GMAC driver is able to transmit " \
+	"CONFIG_NET_NBUF_DATA_SIZE * CONFIG_NET_NBUF_TX_DATA_COUNT is smaller" \
+	"than a full Ethernet frame"
 #endif
 
 #if CONFIG_NET_NBUF_DATA_SIZE & 0x3F
@@ -225,6 +228,7 @@ static void tx_completed(Gmac *gmac, struct gmac_queue *queue)
 
 		tx_desc = &tx_desc_list->buf[tx_desc_list->tail];
 		MODULO_INC(tx_desc_list->tail, tx_desc_list->len);
+		k_sem_give(&queue->tx_desc_sem);
 
 		if (tx_desc->w1 & GMAC_TXW1_LASTBUFFER) {
 			/* Release net buffer to the buffer pool */
@@ -242,19 +246,36 @@ static void tx_completed(Gmac *gmac, struct gmac_queue *queue)
  */
 static void tx_error_handler(Gmac *gmac, struct gmac_queue *queue)
 {
+	struct net_buf *buf;
+	struct ring_buf *tx_frames = &queue->tx_frames;
+
 	queue->err_tx_flushed_count++;
 
 	/* Stop transmission, clean transmit pipeline and control registers */
 	gmac->GMAC_NCR &= ~GMAC_NCR_TXEN;
 
+	/* Free all nbuf resources in the TX path */
+	while (tx_frames->tail != tx_frames->head) {
+		/* Release net buffer to the buffer pool */
+		buf = UINT_TO_POINTER(tx_frames->buf[tx_frames->tail]);
+		net_buf_unref(buf);
+		SYS_LOG_DBG("Dropping buf %p", buf);
+		MODULO_INC(tx_frames->tail, tx_frames->len);
+	}
+
+	/* Reinitialize TX descriptor list */
+	k_sem_reset(&queue->tx_desc_sem);
 	tx_descriptors_init(gmac, queue);
+	for (int i = 0; i < queue->tx_desc_list.len - 1; i++) {
+		k_sem_give(&queue->tx_desc_sem);
+	}
 
 	/* Restart transmission */
 	gmac->GMAC_NCR |=  GMAC_NCR_TXEN;
 }
 
 /*
- * Clean RX queue, any received data stored still in the buffers is abandoned.
+ * Clean RX queue, any received data still stored in the buffers is abandoned.
  */
 static void rx_error_handler(Gmac *gmac, struct gmac_queue *queue)
 {
@@ -379,6 +400,13 @@ static int queue_init(Gmac *gmac, struct gmac_queue *queue)
 
 	tx_descriptors_init(gmac, queue);
 
+	/* Initialize TX descriptors semaphore. The semaphore is required as the
+	 * size of the TX descriptor list is limited while the number of TX data
+	 * buffers is not.
+	 */
+	k_sem_init(&queue->tx_desc_sem, queue->tx_desc_list.len - 1,
+		   queue->tx_desc_list.len - 1);
+
 	/* Set Receive Buffer Queue Pointer Register */
 	gmac->GMAC_RBQB = (uint32_t)queue->rx_desc_list.buf;
 	/* Set Transmit Buffer Queue Pointer Register */
@@ -509,7 +537,7 @@ static struct net_buf *frame_get(struct gmac_queue *queue)
 			DCACHE_INVALIDATE(frag_data, frag_len);
 
 			/* Get a new data net buffer from the buffer pool */
-			new_frag = net_nbuf_get_frag(buf, K_NO_WAIT);
+			new_frag = net_nbuf_get_frag(rx_frame, K_NO_WAIT);
 			if (new_frag == NULL) {
 				queue->err_rx_frames_dropped++;
 				net_buf_unref(rx_frame);
@@ -576,6 +604,8 @@ static int eth_tx(struct net_if *iface, struct net_buf *buf)
 	struct net_buf *frag;
 	uint8_t *frag_data;
 	uint16_t frag_len;
+	uint32_t err_tx_flushed_count_at_entry = queue->err_tx_flushed_count;
+	unsigned int key;
 
 	__ASSERT(buf, "buf pointer is NULL");
 	__ASSERT(buf->frags, "Frame data missing");
@@ -605,6 +635,20 @@ static int eth_tx(struct net_if *iface, struct net_buf *buf)
 		/* Assure cache coherency before DMA read operation */
 		DCACHE_CLEAN(frag_data, frag_len);
 
+		k_sem_take(&queue->tx_desc_sem, K_FOREVER);
+
+		/* The following section becomes critical and requires IRQ lock
+		 * / unlock protection only due to the possibility of executing
+		 * tx_error_handler() function.
+		 */
+		key = irq_lock();
+
+		/* Check if tx_error_handler() function was executed */
+		if (queue->err_tx_flushed_count != err_tx_flushed_count_at_entry) {
+			irq_unlock(key);
+			return -EIO;
+		}
+
 		tx_desc = &tx_desc_list->buf[tx_desc_list->head];
 
 		/* Update buffer descriptor address word */
@@ -626,19 +670,31 @@ static int eth_tx(struct net_if *iface, struct net_buf *buf)
 		__ASSERT(tx_desc_list->head != tx_desc_list->tail,
 			 "tx_desc_list overflow");
 
+		irq_unlock(key);
+
 		/* Continue with the rest of fragments (only data) */
 		frag = frag->frags;
 		frag_data = frag->data;
 		frag_len = frag->len;
 	}
 
+	key = irq_lock();
+
+	/* Check if tx_error_handler() function was executed */
+	if (queue->err_tx_flushed_count != err_tx_flushed_count_at_entry) {
+		irq_unlock(key);
+		return -EIO;
+	}
+
 	/* Ensure the descriptor following the last one is marked as used */
 	tx_desc = &tx_desc_list->buf[tx_desc_list->head];
 	tx_desc->w1 |= GMAC_TXW1_USED;
 
 	/* Account for a sent frame */
 	ring_buf_put(&queue->tx_frames, POINTER_TO_UINT(buf));
 
+	irq_unlock(key);
+
 	/* Start transmission */
 	gmac->GMAC_NCR |= GMAC_NCR_TSTART;
 

diff --git a/drivers/ethernet/eth_sam_gmac_priv.h b/drivers/ethernet/eth_sam_gmac_priv.h
@@ -20,10 +20,9 @@
 /** Total number of queues supported by GMAC hardware module */
 #define GMAC_QUEUE_NO                     3
 /** RX descriptors count for main queue */
-#define MAIN_QUEUE_RX_DESC_COUNT CONFIG_ETH_SAM_GMAC_NBUF_DATA_COUNT
+#define MAIN_QUEUE_RX_DESC_COUNT CONFIG_ETH_SAM_GMAC_NBUF_RX_DATA_COUNT
 /** TX descriptors count for main queue */
-#define MAIN_QUEUE_TX_DESC_COUNT (CONFIG_NET_NBUF_RX_DATA_COUNT - \
-		CONFIG_ETH_SAM_GMAC_NBUF_DATA_COUNT + 1)
+#define MAIN_QUEUE_TX_DESC_COUNT (CONFIG_NET_NBUF_TX_DATA_COUNT + 1)
 /** RX/TX descriptors count for priority queues */
 #define PRIORITY_QUEUE_DESC_COUNT         1
 
@@ -151,6 +150,7 @@ struct gmac_desc_list {
 struct gmac_queue {
 	struct gmac_desc_list rx_desc_list;
 	struct gmac_desc_list tx_desc_list;
+	struct k_sem tx_desc_sem;
 
 	struct ring_buf rx_nbuf_list;
 	struct ring_buf tx_frames;

diff --git a/drivers/ieee802154/Kconfig.cc2520 b/drivers/ieee802154/Kconfig.cc2520
@@ -64,4 +64,41 @@ config IEEE802154_CC2520_INIT_PRIO
 	be ready first (and sometime gpio should be the very first as spi
 	might need it too). And of course it has to start before the net stack.
 
+config IEEE802154_CC2520_RANDOM_MAC
+	bool "Random MAC address"
+	default y
+	help
+	  Generate a random MAC address dynamically.
+
+if ! IEEE802154_CC2520_RANDOM_MAC
+
+config IEEE802154_CC2520_MAC4
+	hex "MAC Address Byte 4"
+	default 0
+	range 0 ff
+	help
+	  This is the byte 4 of the MAC address.
+
+config IEEE802154_CC2520_MAC5
+	hex "MAC Address Byte 5"
+	default 0
+	range 0 ff
+	help
+	  This is the byte 5 of the MAC address.
+
+config IEEE802154_CC2520_MAC6
+	hex "MAC Address Byte 6"
+	default 0
+	range 0 ff
+	help
+	  This is the byte 6 of the MAC address.
+
+config IEEE802154_CC2520_MAC7
+	hex "MAC Address Byte 7"
+	default 0
+	range 0 ff
+	help
+	  This is the byte 7 of the MAC address.
+endif
+
 endif
diff --git a/drivers/ieee802154/ieee802154_cc2520.c b/drivers/ieee802154/ieee802154_cc2520.c
@@ -274,15 +274,24 @@ static bool verify_osc_stabilization(struct cc2520_context *cc2520)
 static inline uint8_t *get_mac(struct device *dev)
 {
 	struct cc2520_context *cc2520 = dev->driver_data;
+
+#if defined(CONFIG_IEEE802154_CC2520_RANDOM_MAC)
 	uint32_t *ptr = (uint32_t *)(cc2520->mac_addr + 4);
 
+	UNALIGNED_PUT(sys_rand32_get(), ptr);
+
+	cc2520->mac_addr[7] = (cc2520->mac_addr[7] & ~0x01) | 0x02;
+#else
+	cc2520->mac_addr[4] = CONFIG_IEEE802154_CC2520_MAC4;
+	cc2520->mac_addr[5] = CONFIG_IEEE802154_CC2520_MAC5;
+	cc2520->mac_addr[6] = CONFIG_IEEE802154_CC2520_MAC6;
+	cc2520->mac_addr[7] = CONFIG_IEEE802154_CC2520_MAC7;
+#endif
+
 	cc2520->mac_addr[0] = 0x00;
 	cc2520->mac_addr[1] = 0x12;
 	cc2520->mac_addr[2] = 0x4b;
 	cc2520->mac_addr[3] = 0x00;
-	UNALIGNED_PUT(sys_rand32_get(), ptr);
-
-	cc2520->mac_addr[7] = (cc2520->mac_addr[7] & ~0x01) | 0x02;
 
 	return cc2520->mac_addr;
 }

diff --git a/drivers/slip/Kconfig b/drivers/slip/Kconfig
@@ -77,4 +77,15 @@ config  SLIP_TAP
 	  By default TUN is used. In TAP the Ethernet frames
 	  are transferred over SLIP.
 
+
+config	SLIP_MAC_ADDR
+	string "MAC address for the interface"
+	default ""
+	help
+	  Specify a MAC address for the SLIP interface in the form of
+	  six hex 8-bit chars separaed by colons (eg:
+	  aa:33:cc:22:e2:c0).  The default is an empty string, which
+	  means the code will make 00:00:5E:00:53:XX, where XX will be
+	  random.
+
 endif