--- /dev/null
+/*
+ * 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 unsigned int seed;
+
+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_r(&seed) & 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_r(&seed) % (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_cond(DEBUG_DEV_PKT, "...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 && (ntohl(ip) & IN_CLASSB_NET) != LINKLOCAL_ADDR) {
+ puts("invalid link address");
+ net_set_state(NETLOOP_FAIL);
+ return;
+ }
+ NetOurSubnetMask = IN_CLASSB_NET;
+
+ seed = seed_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_cond(DEBUG_LL_STATE, "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_cond(DEBUG_LL_STATE, "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_cond(DEBUG_LL_STATE, "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_cond(DEBUG_LL_STATE, "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;
+ IPaddr_t null_ip = 0;
+
+ 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_cond(DEBUG_LL_STATE,
+ "missed an expected timeout\n");
+ timeout_ms = 0;
+ } else {
+ debug_cond(DEBUG_INT_STATE, "adjusting timeout\n");
+ timeout_ms = diff | 1; /* never 0 */
+ }
+ }
+#if 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;
+ */
+ bb_error_msg("iface %s is down", eth_get_name());
+ if (ready) {
+ run(argv, "deconfig", &ip);
+ }
+ return EXIT_FAILURE;
+ }
+ continue;
+ }
+#endif
+
+ debug_cond(DEBUG_INT_STATE, "%s recv arp type=%d, op=%d,\n",
+ eth_get_name(), ntohs(arp->ar_pro),
+ ntohs(arp->ar_op));
+ debug_cond(DEBUG_INT_STATE, "\tsource=%pM %pI4\n",
+ &arp->ar_sha,
+ &arp->ar_spa);
+ debug_cond(DEBUG_INT_STATE, "\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;
+ }
+
+ /*
+ * According to RFC 3927, section 2.2.1:
+ * Check if packet is an ARP probe by checking for a null source IP
+ * then check that target IP is equal to ours and source hw addr
+ * is not equal to ours. This condition should cause a conflict only
+ * during probe.
+ */
+ if (arp->ar_op == htons(ARPOP_REQUEST) &&
+ memcmp(&arp->ar_spa, &null_ip, ARP_PLEN) == 0 &&
+ memcmp(&arp->ar_tpa, &ip, ARP_PLEN) == 0 &&
+ memcmp(&arp->ar_sha, NetOurEther, ARP_HLEN) != 0) {
+ target_ip_conflict = 1;
+ }
+
+ debug_cond(DEBUG_NET_PKT,
+ "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();
+}
Code Review / kvmfornfv.git / blobdiff