net: Add link-local addressing support

Code based on networking/zcip.c in busybox commit 8531d76a15890c2c535908ce888b2e2aed35b172 Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>

net: Add link-local addressing support
Code based on networking/zcip.c in busybox commit 8531d76a15890c2c535908ce888b2e2aed35b172 Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Joe Hershberger
1 parent 228041893c
Showing 8 changed files with 490 additions and 2 deletions Side-by-side Diff
README
common/cmd_net.c
doc/README.link-local
include/net.h
net/Makefile
net/link_local.c
net/link_local.h
net/net.c
@@ -785,6 +785,8 @@
 		CONFIG_CMD_JFFS2	* JFFS2 Support
 		CONFIG_CMD_KGDB		* kgdb
 		CONFIG_CMD_LDRINFO	  ldrinfo (display Blackfin loader)
+		CONFIG_CMD_LINK_LOCAL	* link-local IP address auto-configuration
+					  (169.254.*.*)
 		CONFIG_CMD_LOADB	  loadb
 		CONFIG_CMD_LOADS	  loads
 		CONFIG_CMD_MD5SUM	  print md5 message digest
@@ -1632,6 +1634,14 @@
 		that one of the retries will be successful but note that
 		the DHCP timeout and retry process takes a longer than
 		this delay.
+
+ - Link-local IP address negotiation:
+		Negotiate with other link-local clients on the local network
+		for an address that doesn't require explicit configuration.
+		This is especially useful if a DHCP server cannot be guaranteed
+		to exist in all environments that the device must operate.
+
+		See doc/README.link-local for more information.
  
  - CDP Options:
 		CONFIG_CDP_DEVICE_ID
@@ -428,4 +428,35 @@
 );
  
 #endif	/* CONFIG_CMD_DNS */
+
+#if defined(CONFIG_CMD_LINK_LOCAL)
+static int do_link_local(cmd_tbl_t *cmdtp, int flag, int argc,
+			char * const argv[])
+{
+	char tmp[22];
+
+	if (NetLoop(LINKLOCAL) < 0)
+		return 1;
+
+	NetOurGatewayIP = 0;
+	ip_to_string(NetOurGatewayIP, tmp);
+	setenv("gatewayip", tmp);
+
+	ip_to_string(NetOurSubnetMask, tmp);
+	setenv("netmask", tmp);
+
+	ip_to_string(NetOurIP, tmp);
+	setenv("ipaddr", tmp);
+	setenv("llipaddr", tmp); /* store this for next time */
+
+	return 0;
+}
+
+U_BOOT_CMD(
+	linklocal,	1,	1,	do_link_local,
+	"acquire a network IP address using the link-local protocol",
+	""
+);
+
+#endif  /* CONFIG_CMD_LINK_LOCAL */
+------------------------------------------
+ Link-local IP address auto-configuration
+------------------------------------------
+
+Negotiate with other link-local clients on the local network
+for an address that doesn't require explicit configuration.
+This is especially useful if a DHCP server cannot be guaranteed
+to exist in all environments that the device must operate.
+
+This is an implementation of RFC3927.
+
+----------
+ Commands
+----------
+
+When CONFIG_CMD_LINK_LOCAL is defined in the board config file,
+the "linklocal" command is available.  This running this will
+take approximately 5 seconds while the address is negotiated.
+
+------------------------
+ Environment interation
+------------------------
+
+The "llipaddr" variable is set with the most recently
+negotiated address and is preferred in future negotiations.
+
+The "ipaddr", "netmask", and "gatewayip" variables are set
+after successful negotiation to enable network access.
+
+-------------
+ Limitations
+-------------
+
+RFC3927 requires that addresses are continuously checked to
+avoid conflicts, however this can only happen when the NetLoop
+is getting called.  It is possible for a conflict to go undetected
+until a command that accesses the network is executed.
+
+Using NetConsole is one way to ensure that NetLoop is always
+processing packets and monitoring for conflicts.
+
+This is also not a concern if the feature is use to connect
+directly to another machine that may not be running a DHCP server.
+
+----------------
+ Example script
+----------------
+
+This script allows use of DHCP and/or Link-local controlled
+by env variables.  It depends on CONFIG_CMD_LINK_LOCAL, CONFIG_CMD_DHCP,
+and CONFIG_BOOTP_MAY_FAIL.
+If both fail or are disabled, static settings are used.
+
+#define CONFIG_EXTRA_ENV_SETTINGS \
+	"ipconfigcmd=if test \\\"$dhcpenabled\\\" -ne 0;"		\
+		"then "							\
+			"dhcpfail=0;dhcp || dhcpfail=1;"		\
+		"else "							\
+			"dhcpfail=-1;"					\
+		"fi;"							\
+		"if test \\\"$linklocalenabled\\\" -ne 0 -a "		\
+			"\\\"$dhcpfail\\\" -ne 0;"			\
+		"then "							\
+			"linklocal;"					\
+			"llfail=0;"					\
+		"else "							\
+			"llfail=-1;"					\
+		"fi;"							\
+		"if test \\\"$llfail\\\" -ne 0 -a "			\
+			"\\\"$dhcpfail\\\" -ne 0; "			\
+		"then "							\
+			"setenv ipaddr $sipaddr; "			\
+			"setenv netmask $snetmask; "			\
+			"setenv gatewayip $sgatewayip; "		\
+		"fi;\0"							\
@@ -395,7 +395,7 @@
  
 enum proto_t {
 	BOOTP, RARP, ARP, TFTPGET, DHCP, PING, DNS, NFS, CDP, NETCONS, SNTP,
-	TFTPSRV, TFTPPUT
+	TFTPSRV, TFTPPUT, LINKLOCAL
 };
  
 /* from net/net.c */
@@ -32,15 +32,17 @@
 COBJS-$(CONFIG_CMD_CDP)  += cdp.o
 COBJS-$(CONFIG_CMD_DNS)  += dns.o
 COBJS-$(CONFIG_CMD_NET)  += eth.o
+COBJS-$(CONFIG_CMD_LINK_LOCAL) += link_local.o
 COBJS-$(CONFIG_CMD_NET)  += net.o
 COBJS-$(CONFIG_BOOTP_RANDOM_DELAY) += net_rand.o
+COBJS-$(CONFIG_CMD_LINK_LOCAL) += net_rand.o
 COBJS-$(CONFIG_CMD_NFS)  += nfs.o
 COBJS-$(CONFIG_CMD_PING) += ping.o
 COBJS-$(CONFIG_CMD_RARP) += rarp.o
 COBJS-$(CONFIG_CMD_SNTP) += sntp.o
 COBJS-$(CONFIG_CMD_NET)  += tftp.o
  
-COBJS	:= $(COBJS-y)
+COBJS	:= $(sort $(COBJS-y))
 SRCS	:= $(COBJS:.o=.c)
 OBJS	:= $(addprefix $(obj),$(COBJS))
  
+/*
+ * RFC3927 ZeroConf IPv4 Link-Local addressing
+ * (see <http://www.zeroconf.org/>)
+ *
+ * Copied from BusyBox - networking/zcip.c
+ *
+ * Copyright (C) 2003 by Arthur van Hoff (avh@strangeberry.com)
+ * Copyright (C) 2004 by David Brownell
+ * Copyright (C) 2010 by Joe Hershberger
+ *
+ * Licensed under the GPL v2 or later
+ */
+
+#include <common.h>
+#include <net.h>
+#include "arp.h"
+#include "net_rand.h"
+
+/* We don't need more than 32 bits of the counter */
+#define MONOTONIC_MS() ((unsigned)get_timer(0) * (1000 / CONFIG_SYS_HZ))
+
+enum {
+/* 169.254.0.0 */
+	LINKLOCAL_ADDR = 0xa9fe0000,
+
+	IN_CLASSB_NET = 0xffff0000,
+	IN_CLASSB_HOST = 0x0000ffff,
+
+/* protocol timeout parameters, specified in seconds */
+	PROBE_WAIT = 1,
+	PROBE_MIN = 1,
+	PROBE_MAX = 2,
+	PROBE_NUM = 3,
+	MAX_CONFLICTS = 10,
+	RATE_LIMIT_INTERVAL = 60,
+	ANNOUNCE_WAIT = 2,
+	ANNOUNCE_NUM = 2,
+	ANNOUNCE_INTERVAL = 2,
+	DEFEND_INTERVAL = 10
+};
+
+/* States during the configuration process. */
+static enum ll_state_t {
+	PROBE = 0,
+	RATE_LIMIT_PROBE,
+	ANNOUNCE,
+	MONITOR,
+	DEFEND,
+	DISABLED
+} state = DISABLED;
+
+static IPaddr_t ip;
+static int timeout_ms = -1;
+static unsigned deadline_ms;
+static unsigned conflicts;
+static unsigned nprobes;
+static unsigned nclaims;
+static int ready;
+
+static void link_local_timeout(void);
+
+/**
+ * Pick a random link local IP address on 169.254/16, except that
+ * the first and last 256 addresses are reserved.
+ */
+static IPaddr_t pick(void)
+{
+	unsigned tmp;
+
+	do {
+		tmp = rand() & IN_CLASSB_HOST;
+	} while (tmp > (IN_CLASSB_HOST - 0x0200));
+	return (IPaddr_t) htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
+}
+
+/**
+ * Return milliseconds of random delay, up to "secs" seconds.
+ */
+static inline unsigned random_delay_ms(unsigned secs)
+{
+	return rand() % (secs * 1000);
+}
+
+static void configure_wait(void)
+{
+	if (timeout_ms == -1)
+		return;
+
+	/* poll, being ready to adjust current timeout */
+	if (!timeout_ms)
+		timeout_ms = random_delay_ms(PROBE_WAIT);
+
+	/* set deadline_ms to the point in time when we timeout */
+	deadline_ms = MONOTONIC_MS() + timeout_ms;
+
+	debug("...wait %d %s nprobes=%u, nclaims=%u\n",
+			timeout_ms, eth_get_name(), nprobes, nclaims);
+
+	NetSetTimeout(timeout_ms, link_local_timeout);
+}
+
+void link_local_start(void)
+{
+	ip = getenv_IPaddr("llipaddr");
+	if (ip != 0 && (ip & IN_CLASSB_NET) != LINKLOCAL_ADDR) {
+		puts("invalid link address");
+		net_set_state(NETLOOP_FAIL);
+		return;
+	}
+	NetOurSubnetMask = IN_CLASSB_NET;
+
+	srand_mac();
+	if (ip == 0)
+		ip = pick();
+
+	state = PROBE;
+	timeout_ms = 0;
+	conflicts = 0;
+	nprobes = 0;
+	nclaims = 0;
+	ready = 0;
+
+	configure_wait();
+}
+
+static void link_local_timeout(void)
+{
+	switch (state) {
+	case PROBE:
+		/* timeouts in the PROBE state mean no conflicting ARP packets
+		   have been received, so we can progress through the states */
+		if (nprobes < PROBE_NUM) {
+			nprobes++;
+			debug("probe/%u %s@%pI4\n",
+					nprobes, eth_get_name(), &ip);
+			arp_raw_request(0, NetEtherNullAddr, ip);
+			timeout_ms = PROBE_MIN * 1000;
+			timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN);
+		} else {
+			/* Switch to announce state */
+			state = ANNOUNCE;
+			nclaims = 0;
+			debug("announce/%u %s@%pI4\n",
+					nclaims, eth_get_name(), &ip);
+			arp_raw_request(ip, NetOurEther, ip);
+			timeout_ms = ANNOUNCE_INTERVAL * 1000;
+		}
+		break;
+	case RATE_LIMIT_PROBE:
+		/* timeouts in the RATE_LIMIT_PROBE state mean no conflicting
+		   ARP packets have been received, so we can move immediately
+		   to the announce state */
+		state = ANNOUNCE;
+		nclaims = 0;
+		debug("announce/%u %s@%pI4\n",
+				nclaims, eth_get_name(), &ip);
+		arp_raw_request(ip, NetOurEther, ip);
+		timeout_ms = ANNOUNCE_INTERVAL * 1000;
+		break;
+	case ANNOUNCE:
+		/* timeouts in the ANNOUNCE state mean no conflicting ARP
+		   packets have been received, so we can progress through
+		   the states */
+		if (nclaims < ANNOUNCE_NUM) {
+			nclaims++;
+			debug("announce/%u %s@%pI4\n",
+					nclaims, eth_get_name(), &ip);
+			arp_raw_request(ip, NetOurEther, ip);
+			timeout_ms = ANNOUNCE_INTERVAL * 1000;
+		} else {
+			/* Switch to monitor state */
+			state = MONITOR;
+			printf("Successfully assigned %pI4\n", &ip);
+			NetCopyIP(&NetOurIP, &ip);
+			ready = 1;
+			conflicts = 0;
+			timeout_ms = -1;
+			/* Never timeout in the monitor state */
+			NetSetTimeout(0, NULL);
+
+			/* NOTE: all other exit paths should deconfig ... */
+			net_set_state(NETLOOP_SUCCESS);
+			return;
+		}
+		break;
+	case DEFEND:
+		/* We won!  No ARP replies, so just go back to monitor */
+		state = MONITOR;
+		timeout_ms = -1;
+		conflicts = 0;
+		break;
+	default:
+		/* Invalid, should never happen.  Restart the whole protocol */
+		state = PROBE;
+		ip = pick();
+		timeout_ms = 0;
+		nprobes = 0;
+		nclaims = 0;
+		break;
+	}
+	configure_wait();
+}
+
+void link_local_receive_arp(struct arp_hdr *arp, int len)
+{
+	int source_ip_conflict;
+	int target_ip_conflict;
+
+	if (state == DISABLED)
+		return;
+
+	/* We need to adjust the timeout in case we didn't receive a
+	   conflicting packet. */
+	if (timeout_ms > 0) {
+		unsigned diff = deadline_ms - MONOTONIC_MS();
+		if ((int)(diff) < 0) {
+			/* Current time is greater than the expected timeout
+			   time. This should never happen */
+			debug("missed an expected timeout\n");
+			timeout_ms = 0;
+		} else {
+			debug("adjusting timeout\n");
+			timeout_ms = diff | 1; /* never 0 */
+		}
+	}
+/*
+ * XXX Don't bother with ethernet link just yet
+	if ((fds[0].revents & POLLIN) == 0) {
+		if (fds[0].revents & POLLERR) {
+			// FIXME: links routinely go down;
+			// this shouldn't necessarily exit.
+			bb_error_msg("iface %s is down", eth_get_name());
+			if (ready) {
+				run(argv, "deconfig", &ip);
+			}
+			return EXIT_FAILURE;
+		}
+		continue;
+	}
+*/
+
+	debug("%s recv arp type=%d, op=%d,\n",
+		eth_get_name(), ntohs(arp->ar_pro),
+		ntohs(arp->ar_op));
+	debug("\tsource=%pM %pI4\n",
+		&arp->ar_sha,
+		&arp->ar_spa);
+	debug("\ttarget=%pM %pI4\n",
+		&arp->ar_tha,
+		&arp->ar_tpa);
+
+	if (arp->ar_op != htons(ARPOP_REQUEST)
+	 && arp->ar_op != htons(ARPOP_REPLY)
+	) {
+		configure_wait();
+		return;
+	}
+
+	source_ip_conflict = 0;
+	target_ip_conflict = 0;
+
+	if (memcmp(&arp->ar_spa, &ip, ARP_PLEN) == 0
+	 && memcmp(&arp->ar_sha, NetOurEther, ARP_HLEN) != 0
+	) {
+		source_ip_conflict = 1;
+	}
+	if (arp->ar_op == htons(ARPOP_REQUEST)
+	 && memcmp(&arp->ar_tpa, &ip, ARP_PLEN) == 0
+	 && memcmp(&arp->ar_tha, NetOurEther, ARP_HLEN) != 0
+	) {
+		target_ip_conflict = 1;
+	}
+
+	debug("state = %d, source ip conflict = %d, target ip conflict = %d\n",
+		state, source_ip_conflict, target_ip_conflict);
+	switch (state) {
+	case PROBE:
+	case ANNOUNCE:
+		/* When probing or announcing, check for source IP conflicts
+		   and other hosts doing ARP probes (target IP conflicts). */
+		if (source_ip_conflict || target_ip_conflict) {
+			conflicts++;
+			state = PROBE;
+			if (conflicts >= MAX_CONFLICTS) {
+				debug("%s ratelimit\n", eth_get_name());
+				timeout_ms = RATE_LIMIT_INTERVAL * 1000;
+				state = RATE_LIMIT_PROBE;
+			}
+
+			/* restart the whole protocol */
+			ip = pick();
+			timeout_ms = 0;
+			nprobes = 0;
+			nclaims = 0;
+		}
+		break;
+	case MONITOR:
+		/* If a conflict, we try to defend with a single ARP probe */
+		if (source_ip_conflict) {
+			debug("monitor conflict -- defending\n");
+			state = DEFEND;
+			timeout_ms = DEFEND_INTERVAL * 1000;
+			arp_raw_request(ip, NetOurEther, ip);
+		}
+		break;
+	case DEFEND:
+		/* Well, we tried.  Start over (on conflict) */
+		if (source_ip_conflict) {
+			state = PROBE;
+			debug("defend conflict -- starting over\n");
+			ready = 0;
+			NetOurIP = 0;
+
+			/* restart the whole protocol */
+			ip = pick();
+			timeout_ms = 0;
+			nprobes = 0;
+			nclaims = 0;
+		}
+		break;
+	default:
+		/* Invalid, should never happen.  Restart the whole protocol */
+		debug("invalid state -- starting over\n");
+		state = PROBE;
+		ip = pick();
+		timeout_ms = 0;
+		nprobes = 0;
+		nclaims = 0;
+		break;
+	}
+	configure_wait();
+}
+/*
+ * RFC3927 ZeroConf IPv4 Link-Local addressing
+ * (see <http://www.zeroconf.org/>)
+ *
+ * Copied from BusyBox - networking/zcip.c
+ *
+ * Copyright (C) 2003 by Arthur van Hoff (avh@strangeberry.com)
+ * Copyright (C) 2004 by David Brownell
+ *
+ * Licensed under the GPL v2 or later
+ */
+
+#if defined(CONFIG_CMD_LINK_LOCAL)
+
+#ifndef __LINK_LOCAL_H__
+#define __LINK_LOCAL_H__
+
+#include <common.h>
+
+void link_local_receive_arp(struct arp_hdr *arp, int len);
+void link_local_start(void);
+
+#endif /* __LINK_LOCAL_H__ */
+#endif
@@ -23,6 +23,12 @@
  *			- name of bootfile
  *	Next step:	ARP
  *
+ * LINK_LOCAL:
+ *
+ *	Prerequisites:	- own ethernet address
+ *	We want:	- own IP address
+ *	Next step:	ARP
+ *
  * RARP:
  *
  *	Prerequisites:	- own ethernet address
@@ -89,6 +95,7 @@
 #if defined(CONFIG_CMD_DNS)
 #include "dns.h"
 #endif
+#include "link_local.h"
 #include "nfs.h"
 #include "ping.h"
 #include "rarp.h"
@@ -402,6 +409,11 @@
 			DnsStart();
 			break;
 #endif
+#if defined(CONFIG_CMD_LINK_LOCAL)
+		case LINKLOCAL:
+			link_local_start();
+			break;
+#endif
 		default:
 			break;
 		}
@@ -1194,6 +1206,7 @@
 	case BOOTP:
 	case CDP:
 	case DHCP:
+	case LINKLOCAL:
 		if (memcmp(NetOurEther, "\0\0\0\0\0\0", 6) == 0) {
 			int num = eth_get_dev_index();
...	...	@@ -785,6 +785,8 @@
785	785	CONFIG_CMD_JFFS2 * JFFS2 Support
786	786	CONFIG_CMD_KGDB * kgdb
787	787	CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
	788	+ CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
	789	+ (169.254..)
788	790	CONFIG_CMD_LOADB loadb
789	791	CONFIG_CMD_LOADS loads
790	792	CONFIG_CMD_MD5SUM print md5 message digest
...	...	@@ -1632,6 +1634,14 @@
1632	1634	that one of the retries will be successful but note that
1633	1635	the DHCP timeout and retry process takes a longer than
1634	1636	this delay.
	1637	+
	1638	+ - Link-local IP address negotiation:
	1639	+ Negotiate with other link-local clients on the local network
	1640	+ for an address that doesn't require explicit configuration.
	1641	+ This is especially useful if a DHCP server cannot be guaranteed
	1642	+ to exist in all environments that the device must operate.
	1643	+
	1644	+ See doc/README.link-local for more information.
1635	1645
1636	1646	- CDP Options:
1637	1647	CONFIG_CDP_DEVICE_ID
...	...	@@ -428,4 +428,35 @@
428	428	);
429	429
430	430	#endif /* CONFIG_CMD_DNS */
	431	+
	432	+#if defined(CONFIG_CMD_LINK_LOCAL)
	433	+static int do_link_local(cmd_tbl_t *cmdtp, int flag, int argc,
	434	+ char * const argv[])
	435	+{
	436	+ char tmp[22];
	437	+
	438	+ if (NetLoop(LINKLOCAL) < 0)
	439	+ return 1;
	440	+
	441	+ NetOurGatewayIP = 0;
	442	+ ip_to_string(NetOurGatewayIP, tmp);
	443	+ setenv("gatewayip", tmp);
	444	+
	445	+ ip_to_string(NetOurSubnetMask, tmp);
	446	+ setenv("netmask", tmp);
	447	+
	448	+ ip_to_string(NetOurIP, tmp);
	449	+ setenv("ipaddr", tmp);
	450	+ setenv("llipaddr", tmp); /* store this for next time */
	451	+
	452	+ return 0;
	453	+}
	454	+
	455	+U_BOOT_CMD(
	456	+ linklocal, 1, 1, do_link_local,
	457	+ "acquire a network IP address using the link-local protocol",
	458	+ ""
	459	+);
	460	+
	461	+#endif /* CONFIG_CMD_LINK_LOCAL */
	1	+------------------------------------------
	2	+ Link-local IP address auto-configuration
	3	+------------------------------------------
	4	+
	5	+Negotiate with other link-local clients on the local network
	6	+for an address that doesn't require explicit configuration.
	7	+This is especially useful if a DHCP server cannot be guaranteed
	8	+to exist in all environments that the device must operate.
	9	+
	10	+This is an implementation of RFC3927.
	11	+
	12	+----------
	13	+ Commands
	14	+----------
	15	+
	16	+When CONFIG_CMD_LINK_LOCAL is defined in the board config file,
	17	+the "linklocal" command is available. This running this will
	18	+take approximately 5 seconds while the address is negotiated.
	19	+
	20	+------------------------
	21	+ Environment interation
	22	+------------------------
	23	+
	24	+The "llipaddr" variable is set with the most recently
	25	+negotiated address and is preferred in future negotiations.
	26	+
	27	+The "ipaddr", "netmask", and "gatewayip" variables are set
	28	+after successful negotiation to enable network access.
	29	+
	30	+-------------
	31	+ Limitations
	32	+-------------
	33	+
	34	+RFC3927 requires that addresses are continuously checked to
	35	+avoid conflicts, however this can only happen when the NetLoop
	36	+is getting called. It is possible for a conflict to go undetected
	37	+until a command that accesses the network is executed.
	38	+
	39	+Using NetConsole is one way to ensure that NetLoop is always
	40	+processing packets and monitoring for conflicts.
	41	+
	42	+This is also not a concern if the feature is use to connect
	43	+directly to another machine that may not be running a DHCP server.
	44	+
	45	+----------------
	46	+ Example script
	47	+----------------
	48	+
	49	+This script allows use of DHCP and/or Link-local controlled
	50	+by env variables. It depends on CONFIG_CMD_LINK_LOCAL, CONFIG_CMD_DHCP,
	51	+and CONFIG_BOOTP_MAY_FAIL.
	52	+If both fail or are disabled, static settings are used.
	53	+
	54	+#define CONFIG_EXTRA_ENV_SETTINGS \
	55	+ "ipconfigcmd=if test \\\"$dhcpenabled\\\" -ne 0;" \
	56	+ "then " \
	57	+ "dhcpfail=0;dhcp \|\| dhcpfail=1;" \
	58	+ "else " \
	59	+ "dhcpfail=-1;" \
	60	+ "fi;" \
	61	+ "if test \\\"$linklocalenabled\\\" -ne 0 -a " \
	62	+ "\\\"$dhcpfail\\\" -ne 0;" \
	63	+ "then " \
	64	+ "linklocal;" \
	65	+ "llfail=0;" \
	66	+ "else " \
	67	+ "llfail=-1;" \
	68	+ "fi;" \
	69	+ "if test \\\"$llfail\\\" -ne 0 -a " \
	70	+ "\\\"$dhcpfail\\\" -ne 0; " \
	71	+ "then " \
	72	+ "setenv ipaddr $sipaddr; " \
	73	+ "setenv netmask $snetmask; " \
	74	+ "setenv gatewayip $sgatewayip; " \
	75	+ "fi;\0" \
...	...	@@ -395,7 +395,7 @@
395	395
396	396	enum proto_t {
397	397	BOOTP, RARP, ARP, TFTPGET, DHCP, PING, DNS, NFS, CDP, NETCONS, SNTP,
398		- TFTPSRV, TFTPPUT
	398	+ TFTPSRV, TFTPPUT, LINKLOCAL
399	399	};
400	400
401	401	/* from net/net.c */
...	...	@@ -32,15 +32,17 @@
32	32	COBJS-$(CONFIG_CMD_CDP) += cdp.o
33	33	COBJS-$(CONFIG_CMD_DNS) += dns.o
34	34	COBJS-$(CONFIG_CMD_NET) += eth.o
	35	+COBJS-$(CONFIG_CMD_LINK_LOCAL) += link_local.o
35	36	COBJS-$(CONFIG_CMD_NET) += net.o
36	37	COBJS-$(CONFIG_BOOTP_RANDOM_DELAY) += net_rand.o
	38	+COBJS-$(CONFIG_CMD_LINK_LOCAL) += net_rand.o
37	39	COBJS-$(CONFIG_CMD_NFS) += nfs.o
38	40	COBJS-$(CONFIG_CMD_PING) += ping.o
39	41	COBJS-$(CONFIG_CMD_RARP) += rarp.o
40	42	COBJS-$(CONFIG_CMD_SNTP) += sntp.o
41	43	COBJS-$(CONFIG_CMD_NET) += tftp.o
42	44
43		-COBJS := $(COBJS-y)
	45	+COBJS := $(sort $(COBJS-y))
44	46	SRCS := $(COBJS:.o=.c)
45	47	OBJS := $(addprefix $(obj),$(COBJS))
46	48
	1	+/*
	2	+ * RFC3927 ZeroConf IPv4 Link-Local addressing
	3	+ * (see <http://www.zeroconf.org/>)
	4	+ *
	5	+ * Copied from BusyBox - networking/zcip.c
	6	+ *
	7	+ * Copyright (C) 2003 by Arthur van Hoff (avh@strangeberry.com)
	8	+ * Copyright (C) 2004 by David Brownell
	9	+ * Copyright (C) 2010 by Joe Hershberger
	10	+ *
	11	+ * Licensed under the GPL v2 or later
	12	+ */
	13	+
	14	+#include <common.h>
	15	+#include <net.h>
	16	+#include "arp.h"
	17	+#include "net_rand.h"
	18	+
	19	+/* We don't need more than 32 bits of the counter */
	20	+#define MONOTONIC_MS() ((unsigned)get_timer(0) * (1000 / CONFIG_SYS_HZ))
	21	+
	22	+enum {
	23	+/* 169.254.0.0 */
	24	+ LINKLOCAL_ADDR = 0xa9fe0000,
	25	+
	26	+ IN_CLASSB_NET = 0xffff0000,
	27	+ IN_CLASSB_HOST = 0x0000ffff,
	28	+
	29	+/* protocol timeout parameters, specified in seconds */
	30	+ PROBE_WAIT = 1,
	31	+ PROBE_MIN = 1,
	32	+ PROBE_MAX = 2,
	33	+ PROBE_NUM = 3,
	34	+ MAX_CONFLICTS = 10,
	35	+ RATE_LIMIT_INTERVAL = 60,
	36	+ ANNOUNCE_WAIT = 2,
	37	+ ANNOUNCE_NUM = 2,
	38	+ ANNOUNCE_INTERVAL = 2,
	39	+ DEFEND_INTERVAL = 10
	40	+};
	41	+
	42	+/* States during the configuration process. */
	43	+static enum ll_state_t {
	44	+ PROBE = 0,
	45	+ RATE_LIMIT_PROBE,
	46	+ ANNOUNCE,
	47	+ MONITOR,
	48	+ DEFEND,
	49	+ DISABLED
	50	+} state = DISABLED;
	51	+
	52	+static IPaddr_t ip;
	53	+static int timeout_ms = -1;
	54	+static unsigned deadline_ms;
	55	+static unsigned conflicts;
	56	+static unsigned nprobes;
	57	+static unsigned nclaims;
	58	+static int ready;
	59	+
	60	+static void link_local_timeout(void);
	61	+
	62	+/**
	63	+ * Pick a random link local IP address on 169.254/16, except that
	64	+ * the first and last 256 addresses are reserved.
	65	+ */
	66	+static IPaddr_t pick(void)
	67	+{
	68	+ unsigned tmp;
	69	+
	70	+ do {
	71	+ tmp = rand() & IN_CLASSB_HOST;
	72	+ } while (tmp > (IN_CLASSB_HOST - 0x0200));
	73	+ return (IPaddr_t) htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
	74	+}
	75	+
	76	+/**
	77	+ * Return milliseconds of random delay, up to "secs" seconds.
	78	+ */
	79	+static inline unsigned random_delay_ms(unsigned secs)
	80	+{
	81	+ return rand() % (secs * 1000);
	82	+}
	83	+
	84	+static void configure_wait(void)
	85	+{
	86	+ if (timeout_ms == -1)
	87	+ return;
	88	+
	89	+ /* poll, being ready to adjust current timeout */
	90	+ if (!timeout_ms)
	91	+ timeout_ms = random_delay_ms(PROBE_WAIT);
	92	+
	93	+ /* set deadline_ms to the point in time when we timeout */
	94	+ deadline_ms = MONOTONIC_MS() + timeout_ms;
	95	+
	96	+ debug("...wait %d %s nprobes=%u, nclaims=%u\n",
	97	+ timeout_ms, eth_get_name(), nprobes, nclaims);
	98	+
	99	+ NetSetTimeout(timeout_ms, link_local_timeout);
	100	+}
	101	+
	102	+void link_local_start(void)
	103	+{
	104	+ ip = getenv_IPaddr("llipaddr");
	105	+ if (ip != 0 && (ip & IN_CLASSB_NET) != LINKLOCAL_ADDR) {
	106	+ puts("invalid link address");
	107	+ net_set_state(NETLOOP_FAIL);
	108	+ return;
	109	+ }
	110	+ NetOurSubnetMask = IN_CLASSB_NET;
	111	+
	112	+ srand_mac();
	113	+ if (ip == 0)
	114	+ ip = pick();
	115	+
	116	+ state = PROBE;
	117	+ timeout_ms = 0;
	118	+ conflicts = 0;
	119	+ nprobes = 0;
	120	+ nclaims = 0;
	121	+ ready = 0;
	122	+
	123	+ configure_wait();
	124	+}
	125	+
	126	+static void link_local_timeout(void)
	127	+{
	128	+ switch (state) {
	129	+ case PROBE:
	130	+ /* timeouts in the PROBE state mean no conflicting ARP packets
	131	+ have been received, so we can progress through the states */
	132	+ if (nprobes < PROBE_NUM) {
	133	+ nprobes++;
	134	+ debug("probe/%u %s@%pI4\n",
	135	+ nprobes, eth_get_name(), &ip);
	136	+ arp_raw_request(0, NetEtherNullAddr, ip);
	137	+ timeout_ms = PROBE_MIN * 1000;
	138	+ timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN);
	139	+ } else {
	140	+ /* Switch to announce state */
	141	+ state = ANNOUNCE;
	142	+ nclaims = 0;
	143	+ debug("announce/%u %s@%pI4\n",
	144	+ nclaims, eth_get_name(), &ip);
	145	+ arp_raw_request(ip, NetOurEther, ip);
	146	+ timeout_ms = ANNOUNCE_INTERVAL * 1000;
	147	+ }
	148	+ break;
	149	+ case RATE_LIMIT_PROBE:
	150	+ /* timeouts in the RATE_LIMIT_PROBE state mean no conflicting
	151	+ ARP packets have been received, so we can move immediately
	152	+ to the announce state */
	153	+ state = ANNOUNCE;
	154	+ nclaims = 0;
	155	+ debug("announce/%u %s@%pI4\n",
	156	+ nclaims, eth_get_name(), &ip);
	157	+ arp_raw_request(ip, NetOurEther, ip);
	158	+ timeout_ms = ANNOUNCE_INTERVAL * 1000;
	159	+ break;
	160	+ case ANNOUNCE:
	161	+ /* timeouts in the ANNOUNCE state mean no conflicting ARP
	162	+ packets have been received, so we can progress through
	163	+ the states */
	164	+ if (nclaims < ANNOUNCE_NUM) {
	165	+ nclaims++;
	166	+ debug("announce/%u %s@%pI4\n",
	167	+ nclaims, eth_get_name(), &ip);
	168	+ arp_raw_request(ip, NetOurEther, ip);
	169	+ timeout_ms = ANNOUNCE_INTERVAL * 1000;
	170	+ } else {
	171	+ /* Switch to monitor state */
	172	+ state = MONITOR;
	173	+ printf("Successfully assigned %pI4\n", &ip);
	174	+ NetCopyIP(&NetOurIP, &ip);
	175	+ ready = 1;
	176	+ conflicts = 0;
	177	+ timeout_ms = -1;
	178	+ /* Never timeout in the monitor state */
	179	+ NetSetTimeout(0, NULL);
	180	+
	181	+ /* NOTE: all other exit paths should deconfig ... */
	182	+ net_set_state(NETLOOP_SUCCESS);
	183	+ return;
	184	+ }
	185	+ break;
	186	+ case DEFEND:
	187	+ /* We won! No ARP replies, so just go back to monitor */
	188	+ state = MONITOR;
	189	+ timeout_ms = -1;
	190	+ conflicts = 0;
	191	+ break;
	192	+ default:
	193	+ /* Invalid, should never happen. Restart the whole protocol */
	194	+ state = PROBE;
	195	+ ip = pick();
	196	+ timeout_ms = 0;
	197	+ nprobes = 0;
	198	+ nclaims = 0;
	199	+ break;
	200	+ }
	201	+ configure_wait();
	202	+}
	203	+
	204	+void link_local_receive_arp(struct arp_hdr *arp, int len)
	205	+{
	206	+ int source_ip_conflict;
	207	+ int target_ip_conflict;
	208	+
	209	+ if (state == DISABLED)
	210	+ return;
	211	+
	212	+ /* We need to adjust the timeout in case we didn't receive a
	213	+ conflicting packet. */
	214	+ if (timeout_ms > 0) {
	215	+ unsigned diff = deadline_ms - MONOTONIC_MS();
	216	+ if ((int)(diff) < 0) {
	217	+ /* Current time is greater than the expected timeout
	218	+ time. This should never happen */
	219	+ debug("missed an expected timeout\n");
	220	+ timeout_ms = 0;
	221	+ } else {
	222	+ debug("adjusting timeout\n");
	223	+ timeout_ms = diff \| 1; /* never 0 */
	224	+ }
	225	+ }
	226	+/*
	227	+ * XXX Don't bother with ethernet link just yet
	228	+ if ((fds[0].revents & POLLIN) == 0) {
	229	+ if (fds[0].revents & POLLERR) {
	230	+ // FIXME: links routinely go down;
	231	+ // this shouldn't necessarily exit.
	232	+ bb_error_msg("iface %s is down", eth_get_name());
	233	+ if (ready) {
	234	+ run(argv, "deconfig", &ip);
	235	+ }
	236	+ return EXIT_FAILURE;
	237	+ }
	238	+ continue;
	239	+ }
	240	+*/
	241	+
	242	+ debug("%s recv arp type=%d, op=%d,\n",
	243	+ eth_get_name(), ntohs(arp->ar_pro),
	244	+ ntohs(arp->ar_op));
	245	+ debug("\tsource=%pM %pI4\n",
	246	+ &arp->ar_sha,
	247	+ &arp->ar_spa);
	248	+ debug("\ttarget=%pM %pI4\n",
	249	+ &arp->ar_tha,
	250	+ &arp->ar_tpa);
	251	+
	252	+ if (arp->ar_op != htons(ARPOP_REQUEST)
	253	+ && arp->ar_op != htons(ARPOP_REPLY)
	254	+ ) {
	255	+ configure_wait();
	256	+ return;
	257	+ }
	258	+
	259	+ source_ip_conflict = 0;
	260	+ target_ip_conflict = 0;
	261	+
	262	+ if (memcmp(&arp->ar_spa, &ip, ARP_PLEN) == 0
	263	+ && memcmp(&arp->ar_sha, NetOurEther, ARP_HLEN) != 0
	264	+ ) {
	265	+ source_ip_conflict = 1;
	266	+ }
	267	+ if (arp->ar_op == htons(ARPOP_REQUEST)
	268	+ && memcmp(&arp->ar_tpa, &ip, ARP_PLEN) == 0
	269	+ && memcmp(&arp->ar_tha, NetOurEther, ARP_HLEN) != 0
	270	+ ) {
	271	+ target_ip_conflict = 1;
	272	+ }
	273	+
	274	+ debug("state = %d, source ip conflict = %d, target ip conflict = %d\n",
	275	+ state, source_ip_conflict, target_ip_conflict);
	276	+ switch (state) {
	277	+ case PROBE:
	278	+ case ANNOUNCE:
	279	+ /* When probing or announcing, check for source IP conflicts
	280	+ and other hosts doing ARP probes (target IP conflicts). */
	281	+ if (source_ip_conflict \|\| target_ip_conflict) {
	282	+ conflicts++;
	283	+ state = PROBE;
	284	+ if (conflicts >= MAX_CONFLICTS) {
	285	+ debug("%s ratelimit\n", eth_get_name());
	286	+ timeout_ms = RATE_LIMIT_INTERVAL * 1000;
	287	+ state = RATE_LIMIT_PROBE;
	288	+ }
	289	+
	290	+ /* restart the whole protocol */
	291	+ ip = pick();
	292	+ timeout_ms = 0;
	293	+ nprobes = 0;
	294	+ nclaims = 0;
	295	+ }
	296	+ break;
	297	+ case MONITOR:
	298	+ /* If a conflict, we try to defend with a single ARP probe */
	299	+ if (source_ip_conflict) {
	300	+ debug("monitor conflict -- defending\n");
	301	+ state = DEFEND;
	302	+ timeout_ms = DEFEND_INTERVAL * 1000;
	303	+ arp_raw_request(ip, NetOurEther, ip);
	304	+ }
	305	+ break;
	306	+ case DEFEND:
	307	+ /* Well, we tried. Start over (on conflict) */
	308	+ if (source_ip_conflict) {
	309	+ state = PROBE;
	310	+ debug("defend conflict -- starting over\n");
	311	+ ready = 0;
	312	+ NetOurIP = 0;
	313	+
	314	+ /* restart the whole protocol */
	315	+ ip = pick();
	316	+ timeout_ms = 0;
	317	+ nprobes = 0;
	318	+ nclaims = 0;
	319	+ }
	320	+ break;
	321	+ default:
	322	+ /* Invalid, should never happen. Restart the whole protocol */
	323	+ debug("invalid state -- starting over\n");
	324	+ state = PROBE;
	325	+ ip = pick();
	326	+ timeout_ms = 0;
	327	+ nprobes = 0;
	328	+ nclaims = 0;
	329	+ break;
	330	+ }
	331	+ configure_wait();
	332	+}
...	...	@@ -23,6 +23,12 @@
23	23	* - name of bootfile
24	24	* Next step: ARP
25	25	*
	26	+ * LINK_LOCAL:
	27	+ *
	28	+ * Prerequisites: - own ethernet address
	29	+ * We want: - own IP address
	30	+ * Next step: ARP
	31	+ *
26	32	* RARP:
27	33	*
28	34	* Prerequisites: - own ethernet address
...	...	@@ -89,6 +95,7 @@
89	95	#if defined(CONFIG_CMD_DNS)
90	96	#include "dns.h"
91	97	#endif
	98	+#include "link_local.h"
92	99	#include "nfs.h"
93	100	#include "ping.h"
94	101	#include "rarp.h"
...	...	@@ -402,6 +409,11 @@
402	409	DnsStart();
403	410	break;
404	411	#endif
	412	+#if defined(CONFIG_CMD_LINK_LOCAL)
	413	+ case LINKLOCAL:
	414	+ link_local_start();
	415	+ break;
	416	+#endif
405	417	default:
406	418	break;
407	419	}
...	...	@@ -1194,6 +1206,7 @@
1194	1206	case BOOTP:
1195	1207	case CDP:
1196	1208	case DHCP:
	1209	+ case LINKLOCAL:
1197	1210	if (memcmp(NetOurEther, "\0\0\0\0\0\0", 6) == 0) {
1198	1211	int num = eth_get_dev_index();
1199	1212