[821] | 1 | /*
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| 2 | * RFC3927 ZeroConf IPv4 Link-Local addressing
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| 3 | * (see <http://www.zeroconf.org/>)
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| 4 | *
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| 5 | * Copyright (C) 2003 by Arthur van Hoff (avh@strangeberry.com)
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| 6 | * Copyright (C) 2004 by David Brownell
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| 7 | *
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| 8 | * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
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| 9 | */
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| 10 |
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| 11 | /*
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| 12 | * ZCIP just manages the 169.254.*.* addresses. That network is not
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| 13 | * routed at the IP level, though various proxies or bridges can
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| 14 | * certainly be used. Its naming is built over multicast DNS.
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| 15 | */
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| 16 |
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[904] | 17 | //#define DEBUG
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[821] | 18 |
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| 19 | // TODO:
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| 20 | // - more real-world usage/testing, especially daemon mode
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| 21 | // - kernel packet filters to reduce scheduling noise
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| 22 | // - avoid silent script failures, especially under load...
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| 23 | // - link status monitoring (restart on link-up; stop on link-down)
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| 24 |
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| 25 | #include "busybox.h"
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| 26 | #include <errno.h>
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| 27 | #include <string.h>
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| 28 | #include <syslog.h>
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| 29 | #include <poll.h>
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| 30 | #include <time.h>
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| 31 |
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| 32 | #include <sys/wait.h>
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| 33 |
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| 34 | #include <netinet/ether.h>
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| 35 | #include <net/ethernet.h>
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| 36 | #include <net/if.h>
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| 37 | #include <net/if_arp.h>
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| 38 |
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| 39 | #include <linux/if_packet.h>
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| 40 | #include <linux/sockios.h>
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| 41 |
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| 42 |
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| 43 | struct arp_packet {
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| 44 | struct ether_header hdr;
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[904] | 45 | struct ether_arp arp;
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[821] | 46 | } ATTRIBUTE_PACKED;
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| 47 |
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| 48 | enum {
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| 49 | /* 169.254.0.0 */
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| 50 | LINKLOCAL_ADDR = 0xa9fe0000,
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| 51 |
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| 52 | /* protocol timeout parameters, specified in seconds */
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| 53 | PROBE_WAIT = 1,
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| 54 | PROBE_MIN = 1,
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| 55 | PROBE_MAX = 2,
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| 56 | PROBE_NUM = 3,
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| 57 | MAX_CONFLICTS = 10,
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| 58 | RATE_LIMIT_INTERVAL = 60,
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| 59 | ANNOUNCE_WAIT = 2,
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| 60 | ANNOUNCE_NUM = 2,
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| 61 | ANNOUNCE_INTERVAL = 2,
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| 62 | DEFEND_INTERVAL = 10
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| 63 | };
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| 64 |
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[904] | 65 | /* States during the configuration process. */
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| 66 | enum {
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| 67 | PROBE = 0,
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| 68 | RATE_LIMIT_PROBE,
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| 69 | ANNOUNCE,
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| 70 | MONITOR,
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| 71 | DEFEND
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| 72 | };
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[821] | 73 |
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[904] | 74 | /* Implicitly zero-initialized */
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| 75 | static const struct in_addr null_ip;
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| 76 | static const struct ether_addr null_addr;
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| 77 | static int verbose;
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[821] | 78 |
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| 79 | #define DBG(fmt,args...) \
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| 80 | do { } while (0)
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| 81 | #define VDBG DBG
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| 82 |
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| 83 | /**
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| 84 | * Pick a random link local IP address on 169.254/16, except that
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| 85 | * the first and last 256 addresses are reserved.
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| 86 | */
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| 87 | static void pick(struct in_addr *ip)
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| 88 | {
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| 89 | unsigned tmp;
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| 90 |
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| 91 | /* use cheaper math than lrand48() mod N */
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| 92 | do {
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| 93 | tmp = (lrand48() >> 16) & IN_CLASSB_HOST;
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| 94 | } while (tmp > (IN_CLASSB_HOST - 0x0200));
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| 95 | ip->s_addr = htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
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| 96 | }
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| 97 |
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| 98 | /**
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| 99 | * Broadcast an ARP packet.
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| 100 | */
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| 101 | static int arp(int fd, struct sockaddr *saddr, int op,
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| 102 | const struct ether_addr *source_addr, struct in_addr source_ip,
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| 103 | const struct ether_addr *target_addr, struct in_addr target_ip)
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| 104 | {
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| 105 | struct arp_packet p;
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[904] | 106 | memset(&p, 0, sizeof(p));
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[821] | 107 |
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| 108 | // ether header
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| 109 | p.hdr.ether_type = htons(ETHERTYPE_ARP);
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| 110 | memcpy(p.hdr.ether_shost, source_addr, ETH_ALEN);
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| 111 | memset(p.hdr.ether_dhost, 0xff, ETH_ALEN);
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| 112 |
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| 113 | // arp request
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[904] | 114 | p.arp.arp_hrd = htons(ARPHRD_ETHER);
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| 115 | p.arp.arp_pro = htons(ETHERTYPE_IP);
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| 116 | p.arp.arp_hln = ETH_ALEN;
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| 117 | p.arp.arp_pln = 4;
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| 118 | p.arp.arp_op = htons(op);
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| 119 | memcpy(&p.arp.arp_sha, source_addr, ETH_ALEN);
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| 120 | memcpy(&p.arp.arp_spa, &source_ip, sizeof (p.arp.arp_spa));
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| 121 | memcpy(&p.arp.arp_tha, target_addr, ETH_ALEN);
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| 122 | memcpy(&p.arp.arp_tpa, &target_ip, sizeof (p.arp.arp_tpa));
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[821] | 123 |
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| 124 | // send it
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| 125 | if (sendto(fd, &p, sizeof (p), 0, saddr, sizeof (*saddr)) < 0) {
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| 126 | perror("sendto");
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| 127 | return -errno;
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| 128 | }
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| 129 | return 0;
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| 130 | }
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| 131 |
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| 132 | /**
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| 133 | * Run a script.
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| 134 | */
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| 135 | static int run(char *script, char *arg, char *intf, struct in_addr *ip)
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| 136 | {
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| 137 | int pid, status;
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| 138 | char *why;
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| 139 |
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| 140 | if (script != NULL) {
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| 141 | VDBG("%s run %s %s\n", intf, script, arg);
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| 142 | if (ip != NULL) {
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| 143 | char *addr = inet_ntoa(*ip);
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| 144 | setenv("ip", addr, 1);
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| 145 | syslog(LOG_INFO, "%s %s %s", arg, intf, addr);
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| 146 | }
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| 147 |
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| 148 | pid = vfork();
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| 149 | if (pid < 0) { // error
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| 150 | why = "vfork";
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| 151 | goto bad;
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| 152 | } else if (pid == 0) { // child
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| 153 | execl(script, script, arg, NULL);
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| 154 | perror("execl");
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| 155 | _exit(EXIT_FAILURE);
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| 156 | }
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| 157 |
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| 158 | if (waitpid(pid, &status, 0) <= 0) {
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| 159 | why = "waitpid";
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| 160 | goto bad;
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| 161 | }
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| 162 | if (WEXITSTATUS(status) != 0) {
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| 163 | bb_error_msg("script %s failed, exit=%d\n",
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| 164 | script, WEXITSTATUS(status));
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| 165 | return -errno;
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| 166 | }
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| 167 | }
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| 168 | return 0;
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| 169 | bad:
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| 170 | status = -errno;
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| 171 | syslog(LOG_ERR, "%s %s, %s error: %s",
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| 172 | arg, intf, why, strerror(errno));
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| 173 | return status;
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| 174 | }
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| 175 |
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| 176 |
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| 177 | /**
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| 178 | * Return milliseconds of random delay, up to "secs" seconds.
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| 179 | */
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| 180 | static inline unsigned ms_rdelay(unsigned secs)
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| 181 | {
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| 182 | return lrand48() % (secs * 1000);
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| 183 | }
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| 184 |
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| 185 | /**
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| 186 | * main program
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| 187 | */
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| 188 |
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| 189 | int zcip_main(int argc, char *argv[])
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| 190 | {
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| 191 | char *intf = NULL;
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| 192 | char *script = NULL;
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| 193 | int quit = 0;
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| 194 | int foreground = 0;
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| 195 |
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| 196 | char *why;
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| 197 | struct sockaddr saddr;
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| 198 | struct ether_addr addr;
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| 199 | struct in_addr ip = { 0 };
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| 200 | int fd;
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| 201 | int ready = 0;
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| 202 | suseconds_t timeout = 0; // milliseconds
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| 203 | unsigned conflicts = 0;
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| 204 | unsigned nprobes = 0;
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| 205 | unsigned nclaims = 0;
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| 206 | int t;
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[904] | 207 | int state = PROBE;
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[821] | 208 |
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| 209 | // parse commandline: prog [options] ifname script
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| 210 | while ((t = getopt(argc, argv, "fqr:v")) != EOF) {
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| 211 | switch (t) {
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| 212 | case 'f':
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| 213 | foreground = 1;
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| 214 | continue;
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| 215 | case 'q':
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| 216 | quit = 1;
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| 217 | continue;
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| 218 | case 'r':
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| 219 | if (inet_aton(optarg, &ip) == 0
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| 220 | || (ntohl(ip.s_addr) & IN_CLASSB_NET)
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| 221 | != LINKLOCAL_ADDR) {
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| 222 | bb_error_msg_and_die("invalid link address");
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| 223 | }
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| 224 | continue;
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| 225 | case 'v':
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| 226 | verbose++;
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| 227 | foreground = 1;
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| 228 | continue;
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| 229 | default:
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| 230 | bb_error_msg_and_die("bad option");
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| 231 | }
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| 232 | }
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| 233 | if (optind < argc - 1) {
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| 234 | intf = argv[optind++];
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| 235 | setenv("interface", intf, 1);
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| 236 | script = argv[optind++];
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| 237 | }
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| 238 | if (optind != argc || !intf)
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| 239 | bb_show_usage();
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| 240 | openlog(bb_applet_name, 0, LOG_DAEMON);
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| 241 |
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| 242 | // initialize the interface (modprobe, ifup, etc)
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| 243 | if (run(script, "init", intf, NULL) < 0)
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| 244 | return EXIT_FAILURE;
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| 245 |
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| 246 | // initialize saddr
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| 247 | memset(&saddr, 0, sizeof (saddr));
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| 248 | safe_strncpy(saddr.sa_data, intf, sizeof (saddr.sa_data));
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| 249 |
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| 250 | // open an ARP socket
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| 251 | if ((fd = socket(PF_PACKET, SOCK_PACKET, htons(ETH_P_ARP))) < 0) {
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| 252 | why = "open";
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| 253 | fail:
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| 254 | foreground = 1;
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| 255 | goto bad;
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| 256 | }
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| 257 | // bind to the interface's ARP socket
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| 258 | if (bind(fd, &saddr, sizeof (saddr)) < 0) {
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| 259 | why = "bind";
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| 260 | goto fail;
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| 261 | } else {
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| 262 | struct ifreq ifr;
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| 263 | unsigned short seed[3];
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| 264 |
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| 265 | // get the interface's ethernet address
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| 266 | memset(&ifr, 0, sizeof (ifr));
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| 267 | strncpy(ifr.ifr_name, intf, sizeof (ifr.ifr_name));
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| 268 | if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0) {
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| 269 | why = "get ethernet address";
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| 270 | goto fail;
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| 271 | }
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| 272 | memcpy(&addr, &ifr.ifr_hwaddr.sa_data, ETH_ALEN);
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| 273 |
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| 274 | // start with some stable ip address, either a function of
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| 275 | // the hardware address or else the last address we used.
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| 276 | // NOTE: the sequence of addresses we try changes only
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| 277 | // depending on when we detect conflicts.
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| 278 | memcpy(seed, &ifr.ifr_hwaddr.sa_data, ETH_ALEN);
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| 279 | seed48(seed);
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| 280 | if (ip.s_addr == 0)
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| 281 | pick(&ip);
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| 282 | }
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| 283 |
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| 284 | // FIXME cases to handle:
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| 285 | // - zcip already running!
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| 286 | // - link already has local address... just defend/update
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| 287 |
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| 288 | // daemonize now; don't delay system startup
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| 289 | if (!foreground) {
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| 290 | if (daemon(0, verbose) < 0) {
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| 291 | why = "daemon";
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| 292 | goto bad;
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| 293 | }
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| 294 | syslog(LOG_INFO, "start, interface %s", intf);
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| 295 | }
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| 296 |
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| 297 | // run the dynamic address negotiation protocol,
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| 298 | // restarting after address conflicts:
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| 299 | // - start with some address we want to try
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| 300 | // - short random delay
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| 301 | // - arp probes to see if another host else uses it
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| 302 | // - arp announcements that we're claiming it
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| 303 | // - use it
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| 304 | // - defend it, within limits
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| 305 | while (1) {
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| 306 | struct pollfd fds[1];
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| 307 | struct timeval tv1;
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| 308 | struct arp_packet p;
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| 309 |
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| 310 | fds[0].fd = fd;
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| 311 | fds[0].events = POLLIN;
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| 312 | fds[0].revents = 0;
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| 313 |
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[904] | 314 | int source_ip_conflict = 0;
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| 315 | int target_ip_conflict = 0;
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| 316 |
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[821] | 317 | // poll, being ready to adjust current timeout
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| 318 | if (!timeout) {
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| 319 | timeout = ms_rdelay(PROBE_WAIT);
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| 320 | // FIXME setsockopt(fd, SO_ATTACH_FILTER, ...) to
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| 321 | // make the kernel filter out all packets except
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| 322 | // ones we'd care about.
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| 323 | }
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[904] | 324 | // set tv1 to the point in time when we timeout
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[821] | 325 | gettimeofday(&tv1, NULL);
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| 326 | tv1.tv_usec += (timeout % 1000) * 1000;
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| 327 | while (tv1.tv_usec > 1000000) {
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| 328 | tv1.tv_usec -= 1000000;
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| 329 | tv1.tv_sec++;
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| 330 | }
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| 331 | tv1.tv_sec += timeout / 1000;
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| 332 |
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| 333 | VDBG("...wait %ld %s nprobes=%d, nclaims=%d\n",
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| 334 | timeout, intf, nprobes, nclaims);
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| 335 | switch (poll(fds, 1, timeout)) {
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| 336 |
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[904] | 337 | // timeout
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[821] | 338 | case 0:
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[904] | 339 | VDBG("state = %d\n", state);
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| 340 | switch (state) {
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| 341 | case PROBE:
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| 342 | // timeouts in the PROBE state means no conflicting ARP packets
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| 343 | // have been received, so we can progress through the states
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[821] | 344 | if (nprobes < PROBE_NUM) {
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[904] | 345 | nprobes++;
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| 346 | VDBG("probe/%d %s@%s\n",
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| 347 | nprobes, intf, inet_ntoa(ip));
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| 348 | (void)arp(fd, &saddr, ARPOP_REQUEST,
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| 349 | &addr, null_ip,
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| 350 | &null_addr, ip);
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[821] | 351 | timeout = PROBE_MIN * 1000;
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| 352 | timeout += ms_rdelay(PROBE_MAX
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| 353 | - PROBE_MIN);
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[904] | 354 | }
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| 355 | else {
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| 356 | // Switch to announce state.
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| 357 | state = ANNOUNCE;
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| 358 | nclaims = 0;
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| 359 | VDBG("announce/%d %s@%s\n",
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| 360 | nclaims, intf, inet_ntoa(ip));
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| 361 | (void)arp(fd, &saddr, ARPOP_REQUEST,
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| 362 | &addr, ip,
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| 363 | &addr, ip);
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| 364 | timeout = ANNOUNCE_INTERVAL * 1000;
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| 365 | }
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| 366 | break;
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| 367 | case RATE_LIMIT_PROBE:
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| 368 | // timeouts in the RATE_LIMIT_PROBE state means no conflicting ARP packets
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| 369 | // have been received, so we can move immediately to the announce state
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| 370 | state = ANNOUNCE;
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| 371 | nclaims = 0;
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[821] | 372 | VDBG("announce/%d %s@%s\n",
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| 373 | nclaims, intf, inet_ntoa(ip));
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| 374 | (void)arp(fd, &saddr, ARPOP_REQUEST,
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| 375 | &addr, ip,
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| 376 | &addr, ip);
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[904] | 377 | timeout = ANNOUNCE_INTERVAL * 1000;
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| 378 | break;
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| 379 | case ANNOUNCE:
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| 380 | // timeouts in the ANNOUNCE state means no conflicting ARP packets
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| 381 | // have been received, so we can progress through the states
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[821] | 382 | if (nclaims < ANNOUNCE_NUM) {
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[904] | 383 | nclaims++;
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| 384 | VDBG("announce/%d %s@%s\n",
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| 385 | nclaims, intf, inet_ntoa(ip));
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| 386 | (void)arp(fd, &saddr, ARPOP_REQUEST,
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| 387 | &addr, ip,
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| 388 | &addr, ip);
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[821] | 389 | timeout = ANNOUNCE_INTERVAL * 1000;
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[904] | 390 | }
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| 391 | else {
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| 392 | // Switch to monitor state.
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| 393 | state = MONITOR;
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[821] | 394 | // link is ok to use earlier
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[904] | 395 | // FIXME update filters
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[821] | 396 | run(script, "config", intf, &ip);
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| 397 | ready = 1;
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| 398 | conflicts = 0;
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[904] | 399 | timeout = -1; // Never timeout in the monitor state.
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[821] | 400 |
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| 401 | // NOTE: all other exit paths
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| 402 | // should deconfig ...
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| 403 | if (quit)
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| 404 | return EXIT_SUCCESS;
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| 405 | }
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[904] | 406 | break;
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| 407 | case DEFEND:
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| 408 | // We won! No ARP replies, so just go back to monitor.
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| 409 | state = MONITOR;
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| 410 | timeout = -1;
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| 411 | conflicts = 0;
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| 412 | break;
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| 413 | default:
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| 414 | // Invalid, should never happen. Restart the whole protocol.
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| 415 | state = PROBE;
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| 416 | pick(&ip);
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| 417 | timeout = 0;
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| 418 | nprobes = 0;
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| 419 | nclaims = 0;
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| 420 | break;
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| 421 | } // switch (state)
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| 422 | break; // case 0 (timeout)
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[821] | 423 | // packets arriving
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| 424 | case 1:
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[904] | 425 | // We need to adjust the timeout in case we didn't receive
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| 426 | // a conflicting packet.
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[821] | 427 | if (timeout > 0) {
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| 428 | struct timeval tv2;
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| 429 |
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| 430 | gettimeofday(&tv2, NULL);
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| 431 | if (timercmp(&tv1, &tv2, <)) {
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[904] | 432 | // Current time is greater than the expected timeout time.
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| 433 | // Should never happen.
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| 434 | VDBG("missed an expected timeout\n");
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[821] | 435 | timeout = 0;
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| 436 | } else {
|
---|
[904] | 437 | VDBG("adjusting timeout\n");
|
---|
[821] | 438 | timersub(&tv1, &tv2, &tv1);
|
---|
| 439 | timeout = 1000 * tv1.tv_sec
|
---|
| 440 | + tv1.tv_usec / 1000;
|
---|
| 441 | }
|
---|
| 442 | }
|
---|
[904] | 443 |
|
---|
[821] | 444 | if ((fds[0].revents & POLLIN) == 0) {
|
---|
| 445 | if (fds[0].revents & POLLERR) {
|
---|
| 446 | // FIXME: links routinely go down;
|
---|
| 447 | // this shouldn't necessarily exit.
|
---|
| 448 | bb_error_msg("%s: poll error\n", intf);
|
---|
| 449 | if (ready) {
|
---|
| 450 | run(script, "deconfig",
|
---|
| 451 | intf, &ip);
|
---|
| 452 | }
|
---|
| 453 | return EXIT_FAILURE;
|
---|
| 454 | }
|
---|
| 455 | continue;
|
---|
| 456 | }
|
---|
[904] | 457 |
|
---|
[821] | 458 | // read ARP packet
|
---|
| 459 | if (recv(fd, &p, sizeof (p), 0) < 0) {
|
---|
| 460 | why = "recv";
|
---|
| 461 | goto bad;
|
---|
| 462 | }
|
---|
| 463 | if (p.hdr.ether_type != htons(ETHERTYPE_ARP))
|
---|
| 464 | continue;
|
---|
| 465 |
|
---|
[904] | 466 | #ifdef DEBUG
|
---|
| 467 | {
|
---|
| 468 | struct ether_addr * sha = (struct ether_addr *) p.arp.arp_sha;
|
---|
| 469 | struct ether_addr * tha = (struct ether_addr *) p.arp.arp_tha;
|
---|
| 470 | struct in_addr * spa = (struct in_addr *) p.arp.arp_spa;
|
---|
| 471 | struct in_addr * tpa = (struct in_addr *) p.arp.arp_tpa;
|
---|
| 472 | VDBG("%s recv arp type=%d, op=%d,\n",
|
---|
[821] | 473 | intf, ntohs(p.hdr.ether_type),
|
---|
[904] | 474 | ntohs(p.arp.arp_op));
|
---|
| 475 | VDBG("\tsource=%s %s\n",
|
---|
| 476 | ether_ntoa(sha),
|
---|
| 477 | inet_ntoa(*spa));
|
---|
| 478 | VDBG("\ttarget=%s %s\n",
|
---|
| 479 | ether_ntoa(tha),
|
---|
| 480 | inet_ntoa(*tpa));
|
---|
| 481 | }
|
---|
| 482 | #endif
|
---|
| 483 | if (p.arp.arp_op != htons(ARPOP_REQUEST)
|
---|
| 484 | && p.arp.arp_op != htons(ARPOP_REPLY))
|
---|
[821] | 485 | continue;
|
---|
| 486 |
|
---|
[904] | 487 | if (memcmp(p.arp.arp_spa, &ip.s_addr, sizeof(struct in_addr)) == 0 &&
|
---|
| 488 | memcmp(&addr, &p.arp.arp_sha, ETH_ALEN) != 0) {
|
---|
| 489 | source_ip_conflict = 1;
|
---|
| 490 | }
|
---|
| 491 | if (memcmp(p.arp.arp_tpa, &ip.s_addr, sizeof(struct in_addr)) == 0 &&
|
---|
| 492 | p.arp.arp_op == htons(ARPOP_REQUEST) &&
|
---|
| 493 | memcmp(&addr, &p.arp.arp_tha, ETH_ALEN) != 0) {
|
---|
| 494 | target_ip_conflict = 1;
|
---|
| 495 | }
|
---|
[821] | 496 |
|
---|
[904] | 497 | VDBG("state = %d, source ip conflict = %d, target ip conflict = %d\n",
|
---|
| 498 | state, source_ip_conflict, target_ip_conflict);
|
---|
| 499 | switch (state) {
|
---|
| 500 | case PROBE:
|
---|
| 501 | case ANNOUNCE:
|
---|
| 502 | // When probing or announcing, check for source IP conflicts
|
---|
| 503 | // and other hosts doing ARP probes (target IP conflicts).
|
---|
| 504 | if (source_ip_conflict || target_ip_conflict) {
|
---|
| 505 | conflicts++;
|
---|
| 506 | if (conflicts >= MAX_CONFLICTS) {
|
---|
| 507 | VDBG("%s ratelimit\n", intf);
|
---|
| 508 | timeout = RATE_LIMIT_INTERVAL * 1000;
|
---|
| 509 | state = RATE_LIMIT_PROBE;
|
---|
[821] | 510 | }
|
---|
[904] | 511 |
|
---|
| 512 | // restart the whole protocol
|
---|
| 513 | pick(&ip);
|
---|
| 514 | timeout = 0;
|
---|
| 515 | nprobes = 0;
|
---|
| 516 | nclaims = 0;
|
---|
| 517 | }
|
---|
| 518 | break;
|
---|
| 519 | case MONITOR:
|
---|
| 520 | // If a conflict, we try to defend with a single ARP probe.
|
---|
| 521 | if (source_ip_conflict) {
|
---|
| 522 | VDBG("monitor conflict -- defending\n");
|
---|
| 523 | state = DEFEND;
|
---|
| 524 | timeout = DEFEND_INTERVAL * 1000;
|
---|
| 525 | (void)arp(fd, &saddr,
|
---|
| 526 | ARPOP_REQUEST,
|
---|
| 527 | &addr, ip,
|
---|
| 528 | &addr, ip);
|
---|
| 529 | }
|
---|
| 530 | break;
|
---|
| 531 | case DEFEND:
|
---|
| 532 | // Well, we tried. Start over (on conflict).
|
---|
| 533 | if (source_ip_conflict) {
|
---|
| 534 | state = PROBE;
|
---|
| 535 | VDBG("defend conflict -- starting over\n");
|
---|
[821] | 536 | ready = 0;
|
---|
| 537 | run(script, "deconfig", intf, &ip);
|
---|
[904] | 538 |
|
---|
| 539 | // restart the whole protocol
|
---|
| 540 | pick(&ip);
|
---|
| 541 | timeout = 0;
|
---|
| 542 | nprobes = 0;
|
---|
| 543 | nclaims = 0;
|
---|
[821] | 544 | }
|
---|
[904] | 545 | break;
|
---|
| 546 | default:
|
---|
| 547 | // Invalid, should never happen. Restart the whole protocol.
|
---|
| 548 | VDBG("invalid state -- starting over\n");
|
---|
| 549 | state = PROBE;
|
---|
[821] | 550 | pick(&ip);
|
---|
| 551 | timeout = 0;
|
---|
| 552 | nprobes = 0;
|
---|
| 553 | nclaims = 0;
|
---|
[904] | 554 | break;
|
---|
| 555 | } // switch state
|
---|
[821] | 556 |
|
---|
[904] | 557 | break; // case 1 (packets arriving)
|
---|
[821] | 558 | default:
|
---|
| 559 | why = "poll";
|
---|
| 560 | goto bad;
|
---|
[904] | 561 | } // switch poll
|
---|
[821] | 562 | }
|
---|
| 563 | bad:
|
---|
| 564 | if (foreground)
|
---|
| 565 | perror(why);
|
---|
| 566 | else
|
---|
| 567 | syslog(LOG_ERR, "%s %s, %s error: %s",
|
---|
| 568 | bb_applet_name, intf, why, strerror(errno));
|
---|
| 569 | return EXIT_FAILURE;
|
---|
| 570 | }
|
---|