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>
This commit is contained in:
parent
228041893c
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10
README
10
README
@ -785,6 +785,8 @@ The following options need to be configured:
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CONFIG_CMD_JFFS2 * JFFS2 Support
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CONFIG_CMD_KGDB * kgdb
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CONFIG_CMD_LDRINFO ldrinfo (display Blackfin loader)
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CONFIG_CMD_LINK_LOCAL * link-local IP address auto-configuration
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(169.254.*.*)
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CONFIG_CMD_LOADB loadb
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CONFIG_CMD_LOADS loads
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CONFIG_CMD_MD5SUM print md5 message digest
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@ -1633,6 +1635,14 @@ The following options need to be configured:
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the DHCP timeout and retry process takes a longer than
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this delay.
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- Link-local IP address negotiation:
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Negotiate with other link-local clients on the local network
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for an address that doesn't require explicit configuration.
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This is especially useful if a DHCP server cannot be guaranteed
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to exist in all environments that the device must operate.
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See doc/README.link-local for more information.
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- CDP Options:
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CONFIG_CDP_DEVICE_ID
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@ -428,3 +428,34 @@ U_BOOT_CMD(
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);
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#endif /* CONFIG_CMD_DNS */
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#if defined(CONFIG_CMD_LINK_LOCAL)
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static int do_link_local(cmd_tbl_t *cmdtp, int flag, int argc,
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char * const argv[])
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{
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char tmp[22];
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if (NetLoop(LINKLOCAL) < 0)
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return 1;
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NetOurGatewayIP = 0;
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ip_to_string(NetOurGatewayIP, tmp);
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setenv("gatewayip", tmp);
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ip_to_string(NetOurSubnetMask, tmp);
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setenv("netmask", tmp);
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ip_to_string(NetOurIP, tmp);
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setenv("ipaddr", tmp);
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setenv("llipaddr", tmp); /* store this for next time */
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return 0;
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}
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U_BOOT_CMD(
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linklocal, 1, 1, do_link_local,
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"acquire a network IP address using the link-local protocol",
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""
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);
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#endif /* CONFIG_CMD_LINK_LOCAL */
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76
doc/README.link-local
Normal file
76
doc/README.link-local
Normal file
@ -0,0 +1,76 @@
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------------------------------------------
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Link-local IP address auto-configuration
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------------------------------------------
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Negotiate with other link-local clients on the local network
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for an address that doesn't require explicit configuration.
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This is especially useful if a DHCP server cannot be guaranteed
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to exist in all environments that the device must operate.
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This is an implementation of RFC3927.
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----------
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Commands
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----------
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When CONFIG_CMD_LINK_LOCAL is defined in the board config file,
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the "linklocal" command is available. This running this will
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take approximately 5 seconds while the address is negotiated.
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------------------------
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Environment interation
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------------------------
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The "llipaddr" variable is set with the most recently
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negotiated address and is preferred in future negotiations.
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The "ipaddr", "netmask", and "gatewayip" variables are set
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after successful negotiation to enable network access.
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-------------
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Limitations
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-------------
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RFC3927 requires that addresses are continuously checked to
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avoid conflicts, however this can only happen when the NetLoop
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is getting called. It is possible for a conflict to go undetected
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until a command that accesses the network is executed.
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Using NetConsole is one way to ensure that NetLoop is always
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processing packets and monitoring for conflicts.
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This is also not a concern if the feature is use to connect
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directly to another machine that may not be running a DHCP server.
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----------------
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Example script
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----------------
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This script allows use of DHCP and/or Link-local controlled
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by env variables. It depends on CONFIG_CMD_LINK_LOCAL, CONFIG_CMD_DHCP,
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and CONFIG_BOOTP_MAY_FAIL.
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If both fail or are disabled, static settings are used.
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#define CONFIG_EXTRA_ENV_SETTINGS \
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"ipconfigcmd=if test \\\"$dhcpenabled\\\" -ne 0;" \
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"then " \
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"dhcpfail=0;dhcp || dhcpfail=1;" \
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"else " \
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"dhcpfail=-1;" \
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"fi;" \
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"if test \\\"$linklocalenabled\\\" -ne 0 -a " \
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"\\\"$dhcpfail\\\" -ne 0;" \
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"then " \
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"linklocal;" \
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"llfail=0;" \
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"else " \
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"llfail=-1;" \
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"fi;" \
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"if test \\\"$llfail\\\" -ne 0 -a " \
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"\\\"$dhcpfail\\\" -ne 0; " \
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"then " \
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"setenv ipaddr $sipaddr; " \
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"setenv netmask $snetmask; " \
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"setenv gatewayip $sgatewayip; " \
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"fi;\0" \
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@ -395,7 +395,7 @@ extern int NetRestartWrap; /* Tried all network devices */
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enum proto_t {
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BOOTP, RARP, ARP, TFTPGET, DHCP, PING, DNS, NFS, CDP, NETCONS, SNTP,
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TFTPSRV, TFTPPUT
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TFTPSRV, TFTPPUT, LINKLOCAL
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};
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/* from net/net.c */
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@ -32,15 +32,17 @@ COBJS-$(CONFIG_CMD_NET) += bootp.o
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COBJS-$(CONFIG_CMD_CDP) += cdp.o
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COBJS-$(CONFIG_CMD_DNS) += dns.o
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COBJS-$(CONFIG_CMD_NET) += eth.o
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COBJS-$(CONFIG_CMD_LINK_LOCAL) += link_local.o
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COBJS-$(CONFIG_CMD_NET) += net.o
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COBJS-$(CONFIG_BOOTP_RANDOM_DELAY) += net_rand.o
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COBJS-$(CONFIG_CMD_LINK_LOCAL) += net_rand.o
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COBJS-$(CONFIG_CMD_NFS) += nfs.o
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COBJS-$(CONFIG_CMD_PING) += ping.o
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COBJS-$(CONFIG_CMD_RARP) += rarp.o
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COBJS-$(CONFIG_CMD_SNTP) += sntp.o
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COBJS-$(CONFIG_CMD_NET) += tftp.o
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COBJS := $(COBJS-y)
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COBJS := $(sort $(COBJS-y))
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SRCS := $(COBJS:.o=.c)
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OBJS := $(addprefix $(obj),$(COBJS))
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332
net/link_local.c
Normal file
332
net/link_local.c
Normal file
@ -0,0 +1,332 @@
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/*
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* RFC3927 ZeroConf IPv4 Link-Local addressing
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* (see <http://www.zeroconf.org/>)
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*
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* Copied from BusyBox - networking/zcip.c
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*
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* Copyright (C) 2003 by Arthur van Hoff (avh@strangeberry.com)
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* Copyright (C) 2004 by David Brownell
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* Copyright (C) 2010 by Joe Hershberger
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*
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* Licensed under the GPL v2 or later
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*/
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#include <common.h>
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#include <net.h>
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#include "arp.h"
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#include "net_rand.h"
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/* We don't need more than 32 bits of the counter */
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#define MONOTONIC_MS() ((unsigned)get_timer(0) * (1000 / CONFIG_SYS_HZ))
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enum {
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/* 169.254.0.0 */
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LINKLOCAL_ADDR = 0xa9fe0000,
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IN_CLASSB_NET = 0xffff0000,
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IN_CLASSB_HOST = 0x0000ffff,
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/* protocol timeout parameters, specified in seconds */
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PROBE_WAIT = 1,
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PROBE_MIN = 1,
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PROBE_MAX = 2,
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PROBE_NUM = 3,
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MAX_CONFLICTS = 10,
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RATE_LIMIT_INTERVAL = 60,
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ANNOUNCE_WAIT = 2,
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ANNOUNCE_NUM = 2,
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ANNOUNCE_INTERVAL = 2,
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DEFEND_INTERVAL = 10
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};
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/* States during the configuration process. */
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static enum ll_state_t {
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PROBE = 0,
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RATE_LIMIT_PROBE,
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ANNOUNCE,
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MONITOR,
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DEFEND,
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DISABLED
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} state = DISABLED;
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static IPaddr_t ip;
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static int timeout_ms = -1;
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static unsigned deadline_ms;
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static unsigned conflicts;
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static unsigned nprobes;
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static unsigned nclaims;
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static int ready;
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static void link_local_timeout(void);
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/**
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* Pick a random link local IP address on 169.254/16, except that
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* the first and last 256 addresses are reserved.
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*/
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static IPaddr_t pick(void)
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{
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unsigned tmp;
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do {
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tmp = rand() & IN_CLASSB_HOST;
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} while (tmp > (IN_CLASSB_HOST - 0x0200));
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return (IPaddr_t) htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
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}
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/**
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* Return milliseconds of random delay, up to "secs" seconds.
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*/
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static inline unsigned random_delay_ms(unsigned secs)
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{
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return rand() % (secs * 1000);
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}
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static void configure_wait(void)
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{
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if (timeout_ms == -1)
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return;
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/* poll, being ready to adjust current timeout */
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if (!timeout_ms)
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timeout_ms = random_delay_ms(PROBE_WAIT);
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/* set deadline_ms to the point in time when we timeout */
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deadline_ms = MONOTONIC_MS() + timeout_ms;
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debug("...wait %d %s nprobes=%u, nclaims=%u\n",
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timeout_ms, eth_get_name(), nprobes, nclaims);
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NetSetTimeout(timeout_ms, link_local_timeout);
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}
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void link_local_start(void)
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{
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ip = getenv_IPaddr("llipaddr");
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if (ip != 0 && (ip & IN_CLASSB_NET) != LINKLOCAL_ADDR) {
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puts("invalid link address");
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net_set_state(NETLOOP_FAIL);
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return;
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}
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NetOurSubnetMask = IN_CLASSB_NET;
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srand_mac();
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if (ip == 0)
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ip = pick();
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state = PROBE;
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timeout_ms = 0;
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conflicts = 0;
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nprobes = 0;
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nclaims = 0;
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ready = 0;
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configure_wait();
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}
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static void link_local_timeout(void)
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{
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switch (state) {
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case PROBE:
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/* timeouts in the PROBE state mean no conflicting ARP packets
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have been received, so we can progress through the states */
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if (nprobes < PROBE_NUM) {
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nprobes++;
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debug("probe/%u %s@%pI4\n",
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nprobes, eth_get_name(), &ip);
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arp_raw_request(0, NetEtherNullAddr, ip);
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timeout_ms = PROBE_MIN * 1000;
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timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN);
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} else {
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/* Switch to announce state */
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state = ANNOUNCE;
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nclaims = 0;
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debug("announce/%u %s@%pI4\n",
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nclaims, eth_get_name(), &ip);
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arp_raw_request(ip, NetOurEther, ip);
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timeout_ms = ANNOUNCE_INTERVAL * 1000;
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}
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break;
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case RATE_LIMIT_PROBE:
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/* timeouts in the RATE_LIMIT_PROBE state mean no conflicting
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ARP packets have been received, so we can move immediately
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to the announce state */
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state = ANNOUNCE;
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nclaims = 0;
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debug("announce/%u %s@%pI4\n",
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nclaims, eth_get_name(), &ip);
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arp_raw_request(ip, NetOurEther, ip);
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timeout_ms = ANNOUNCE_INTERVAL * 1000;
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break;
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case ANNOUNCE:
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/* timeouts in the ANNOUNCE state mean no conflicting ARP
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packets have been received, so we can progress through
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the states */
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if (nclaims < ANNOUNCE_NUM) {
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nclaims++;
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debug("announce/%u %s@%pI4\n",
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nclaims, eth_get_name(), &ip);
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arp_raw_request(ip, NetOurEther, ip);
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timeout_ms = ANNOUNCE_INTERVAL * 1000;
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} else {
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/* Switch to monitor state */
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state = MONITOR;
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printf("Successfully assigned %pI4\n", &ip);
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NetCopyIP(&NetOurIP, &ip);
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ready = 1;
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conflicts = 0;
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timeout_ms = -1;
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/* Never timeout in the monitor state */
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NetSetTimeout(0, NULL);
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/* NOTE: all other exit paths should deconfig ... */
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net_set_state(NETLOOP_SUCCESS);
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return;
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}
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break;
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case DEFEND:
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/* We won! No ARP replies, so just go back to monitor */
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state = MONITOR;
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timeout_ms = -1;
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conflicts = 0;
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break;
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default:
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/* Invalid, should never happen. Restart the whole protocol */
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state = PROBE;
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ip = pick();
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timeout_ms = 0;
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nprobes = 0;
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nclaims = 0;
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break;
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}
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configure_wait();
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}
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void link_local_receive_arp(struct arp_hdr *arp, int len)
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{
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int source_ip_conflict;
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int target_ip_conflict;
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if (state == DISABLED)
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return;
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/* We need to adjust the timeout in case we didn't receive a
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conflicting packet. */
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if (timeout_ms > 0) {
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unsigned diff = deadline_ms - MONOTONIC_MS();
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if ((int)(diff) < 0) {
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/* Current time is greater than the expected timeout
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time. This should never happen */
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debug("missed an expected timeout\n");
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timeout_ms = 0;
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} else {
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debug("adjusting timeout\n");
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timeout_ms = diff | 1; /* never 0 */
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}
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}
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/*
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* XXX Don't bother with ethernet link just yet
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if ((fds[0].revents & POLLIN) == 0) {
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if (fds[0].revents & POLLERR) {
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// FIXME: links routinely go down;
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// this shouldn't necessarily exit.
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bb_error_msg("iface %s is down", eth_get_name());
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if (ready) {
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run(argv, "deconfig", &ip);
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}
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return EXIT_FAILURE;
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}
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continue;
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}
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*/
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debug("%s recv arp type=%d, op=%d,\n",
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eth_get_name(), ntohs(arp->ar_pro),
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ntohs(arp->ar_op));
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debug("\tsource=%pM %pI4\n",
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&arp->ar_sha,
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&arp->ar_spa);
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debug("\ttarget=%pM %pI4\n",
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&arp->ar_tha,
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&arp->ar_tpa);
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if (arp->ar_op != htons(ARPOP_REQUEST)
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&& arp->ar_op != htons(ARPOP_REPLY)
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) {
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configure_wait();
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return;
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}
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source_ip_conflict = 0;
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target_ip_conflict = 0;
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if (memcmp(&arp->ar_spa, &ip, ARP_PLEN) == 0
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&& memcmp(&arp->ar_sha, NetOurEther, ARP_HLEN) != 0
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) {
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source_ip_conflict = 1;
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}
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if (arp->ar_op == htons(ARPOP_REQUEST)
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&& memcmp(&arp->ar_tpa, &ip, ARP_PLEN) == 0
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&& memcmp(&arp->ar_tha, NetOurEther, ARP_HLEN) != 0
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) {
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target_ip_conflict = 1;
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}
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debug("state = %d, source ip conflict = %d, target ip conflict = %d\n",
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state, source_ip_conflict, target_ip_conflict);
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switch (state) {
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case PROBE:
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case ANNOUNCE:
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/* When probing or announcing, check for source IP conflicts
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and other hosts doing ARP probes (target IP conflicts). */
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if (source_ip_conflict || target_ip_conflict) {
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conflicts++;
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state = PROBE;
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if (conflicts >= MAX_CONFLICTS) {
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debug("%s ratelimit\n", eth_get_name());
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timeout_ms = RATE_LIMIT_INTERVAL * 1000;
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state = RATE_LIMIT_PROBE;
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}
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/* restart the whole protocol */
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ip = pick();
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timeout_ms = 0;
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nprobes = 0;
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nclaims = 0;
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}
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break;
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case MONITOR:
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/* If a conflict, we try to defend with a single ARP probe */
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if (source_ip_conflict) {
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debug("monitor conflict -- defending\n");
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state = DEFEND;
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timeout_ms = DEFEND_INTERVAL * 1000;
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arp_raw_request(ip, NetOurEther, ip);
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}
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break;
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case DEFEND:
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/* Well, we tried. Start over (on conflict) */
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if (source_ip_conflict) {
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state = PROBE;
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debug("defend conflict -- starting over\n");
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ready = 0;
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NetOurIP = 0;
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/* restart the whole protocol */
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ip = pick();
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timeout_ms = 0;
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nprobes = 0;
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nclaims = 0;
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}
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break;
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default:
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/* 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();
|
||||
}
|
24
net/link_local.h
Normal file
24
net/link_local.h
Normal file
@ -0,0 +1,24 @@
|
||||
/*
|
||||
* 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
|
13
net/net.c
13
net/net.c
@ -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"
|
||||
@ -401,6 +408,11 @@ restart:
|
||||
case DNS:
|
||||
DnsStart();
|
||||
break;
|
||||
#endif
|
||||
#if defined(CONFIG_CMD_LINK_LOCAL)
|
||||
case LINKLOCAL:
|
||||
link_local_start();
|
||||
break;
|
||||
#endif
|
||||
default:
|
||||
break;
|
||||
@ -1194,6 +1206,7 @@ common:
|
||||
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();
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user