[3320] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 4 | *
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| 5 | * Author: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
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| 6 | * Busybox port: Nick Fedchik <nick@fedchik.org.ua>
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| 7 | */
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| 8 |
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| 9 | #include <arpa/inet.h>
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| 10 | #include <net/if.h>
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| 11 | #include <netinet/ether.h>
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| 12 | #include <netpacket/packet.h>
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| 13 |
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| 14 | #include "libbb.h"
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| 15 |
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| 16 | /* We don't expect to see 1000+ seconds delay, unsigned is enough */
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| 17 | #define MONOTONIC_US() ((unsigned)monotonic_us())
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| 18 |
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| 19 | enum {
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| 20 | DAD = 1,
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| 21 | UNSOLICITED = 2,
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| 22 | ADVERT = 4,
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| 23 | QUIET = 8,
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| 24 | QUIT_ON_REPLY = 16,
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| 25 | BCAST_ONLY = 32,
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| 26 | UNICASTING = 64
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| 27 | };
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| 28 |
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| 29 | struct globals {
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| 30 | struct in_addr src;
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| 31 | struct in_addr dst;
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| 32 | struct sockaddr_ll me;
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| 33 | struct sockaddr_ll he;
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| 34 | int sock_fd;
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| 35 |
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| 36 | int count; // = -1;
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| 37 | unsigned last;
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| 38 | unsigned timeout_us;
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| 39 | unsigned start;
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| 40 |
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| 41 | unsigned sent;
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| 42 | unsigned brd_sent;
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| 43 | unsigned received;
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| 44 | unsigned brd_recv;
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| 45 | unsigned req_recv;
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| 46 | } FIX_ALIASING;
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| 47 | #define G (*(struct globals*)&bb_common_bufsiz1)
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| 48 | #define src (G.src )
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| 49 | #define dst (G.dst )
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| 50 | #define me (G.me )
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| 51 | #define he (G.he )
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| 52 | #define sock_fd (G.sock_fd )
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| 53 | #define count (G.count )
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| 54 | #define last (G.last )
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| 55 | #define timeout_us (G.timeout_us)
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| 56 | #define start (G.start )
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| 57 | #define sent (G.sent )
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| 58 | #define brd_sent (G.brd_sent )
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| 59 | #define received (G.received )
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| 60 | #define brd_recv (G.brd_recv )
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| 61 | #define req_recv (G.req_recv )
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| 62 | #define INIT_G() do { \
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| 63 | count = -1; \
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| 64 | } while (0)
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| 65 |
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| 66 | // If GNUisms are not available...
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| 67 | //static void *mempcpy(void *_dst, const void *_src, int n)
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| 68 | //{
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| 69 | // memcpy(_dst, _src, n);
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| 70 | // return (char*)_dst + n;
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| 71 | //}
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| 72 |
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| 73 | static int send_pack(struct in_addr *src_addr,
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| 74 | struct in_addr *dst_addr, struct sockaddr_ll *ME,
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| 75 | struct sockaddr_ll *HE)
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| 76 | {
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| 77 | int err;
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| 78 | unsigned char buf[256];
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| 79 | struct arphdr *ah = (struct arphdr *) buf;
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| 80 | unsigned char *p = (unsigned char *) (ah + 1);
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| 81 |
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| 82 | ah->ar_hrd = htons(ARPHRD_ETHER);
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| 83 | ah->ar_pro = htons(ETH_P_IP);
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| 84 | ah->ar_hln = ME->sll_halen;
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| 85 | ah->ar_pln = 4;
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| 86 | ah->ar_op = option_mask32 & ADVERT ? htons(ARPOP_REPLY) : htons(ARPOP_REQUEST);
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| 87 |
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| 88 | p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
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| 89 | p = mempcpy(p, src_addr, 4);
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| 90 |
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| 91 | if (option_mask32 & ADVERT)
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| 92 | p = mempcpy(p, &ME->sll_addr, ah->ar_hln);
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| 93 | else
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| 94 | p = mempcpy(p, &HE->sll_addr, ah->ar_hln);
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| 95 |
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| 96 | p = mempcpy(p, dst_addr, 4);
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| 97 |
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| 98 | err = sendto(sock_fd, buf, p - buf, 0, (struct sockaddr *) HE, sizeof(*HE));
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| 99 | if (err == p - buf) {
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| 100 | last = MONOTONIC_US();
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| 101 | sent++;
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| 102 | if (!(option_mask32 & UNICASTING))
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| 103 | brd_sent++;
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| 104 | }
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| 105 | return err;
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| 106 | }
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| 107 |
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| 108 | static void finish(void) NORETURN;
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| 109 | static void finish(void)
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| 110 | {
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| 111 | if (!(option_mask32 & QUIET)) {
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| 112 | printf("Sent %u probe(s) (%u broadcast(s))\n"
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| 113 | "Received %u repl%s"
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| 114 | " (%u request(s), %u broadcast(s))\n",
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| 115 | sent, brd_sent,
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| 116 | received, (received == 1) ? "ies" : "y",
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| 117 | req_recv, brd_recv);
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| 118 | }
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| 119 | if (option_mask32 & DAD)
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| 120 | exit(!!received);
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| 121 | if (option_mask32 & UNSOLICITED)
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| 122 | exit(EXIT_SUCCESS);
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| 123 | exit(!received);
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| 124 | }
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| 125 |
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| 126 | static void catcher(void)
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| 127 | {
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| 128 | unsigned now;
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| 129 |
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| 130 | now = MONOTONIC_US();
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| 131 | if (start == 0)
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| 132 | start = now;
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| 133 |
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| 134 | if (count == 0 || (timeout_us && (now - start) > timeout_us))
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| 135 | finish();
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| 136 |
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| 137 | /* count < 0 means "infinite count" */
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| 138 | if (count > 0)
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| 139 | count--;
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| 140 |
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| 141 | if (last == 0 || (now - last) > 500000) {
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| 142 | send_pack(&src, &dst, &me, &he);
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| 143 | if (count == 0 && (option_mask32 & UNSOLICITED))
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| 144 | finish();
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| 145 | }
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| 146 | alarm(1);
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| 147 | }
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| 148 |
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| 149 | static bool recv_pack(unsigned char *buf, int len, struct sockaddr_ll *FROM)
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| 150 | {
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| 151 | struct arphdr *ah = (struct arphdr *) buf;
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| 152 | unsigned char *p = (unsigned char *) (ah + 1);
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| 153 | struct in_addr src_ip, dst_ip;
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| 154 | /* moves below assume in_addr is 4 bytes big, ensure that */
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| 155 | struct BUG_in_addr_must_be_4 {
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| 156 | char BUG_in_addr_must_be_4[
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| 157 | sizeof(struct in_addr) == 4 ? 1 : -1
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| 158 | ];
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| 159 | char BUG_s_addr_must_be_4[
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| 160 | sizeof(src_ip.s_addr) == 4 ? 1 : -1
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| 161 | ];
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| 162 | };
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| 163 |
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| 164 | /* Filter out wild packets */
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| 165 | if (FROM->sll_pkttype != PACKET_HOST
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| 166 | && FROM->sll_pkttype != PACKET_BROADCAST
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| 167 | && FROM->sll_pkttype != PACKET_MULTICAST)
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| 168 | return false;
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| 169 |
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| 170 | /* Only these types are recognized */
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| 171 | if (ah->ar_op != htons(ARPOP_REQUEST) && ah->ar_op != htons(ARPOP_REPLY))
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| 172 | return false;
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| 173 |
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| 174 | /* ARPHRD check and this darned FDDI hack here :-( */
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| 175 | if (ah->ar_hrd != htons(FROM->sll_hatype)
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| 176 | && (FROM->sll_hatype != ARPHRD_FDDI || ah->ar_hrd != htons(ARPHRD_ETHER)))
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| 177 | return false;
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| 178 |
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| 179 | /* Protocol must be IP. */
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| 180 | if (ah->ar_pro != htons(ETH_P_IP)
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| 181 | || (ah->ar_pln != 4)
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| 182 | || (ah->ar_hln != me.sll_halen)
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| 183 | || (len < (int)(sizeof(*ah) + 2 * (4 + ah->ar_hln))))
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| 184 | return false;
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| 185 |
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| 186 | move_from_unaligned32(src_ip.s_addr, p + ah->ar_hln);
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| 187 | move_from_unaligned32(dst_ip.s_addr, p + ah->ar_hln + 4 + ah->ar_hln);
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| 188 |
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| 189 | if (dst.s_addr != src_ip.s_addr)
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| 190 | return false;
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| 191 | if (!(option_mask32 & DAD)) {
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| 192 | if ((src.s_addr != dst_ip.s_addr)
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| 193 | || (memcmp(p + ah->ar_hln + 4, &me.sll_addr, ah->ar_hln)))
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| 194 | return false;
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| 195 | } else {
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| 196 | /* DAD packet was:
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| 197 | src_ip = 0 (or some src)
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| 198 | src_hw = ME
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| 199 | dst_ip = tested address
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| 200 | dst_hw = <unspec>
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| 201 |
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| 202 | We fail, if receive request/reply with:
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| 203 | src_ip = tested_address
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| 204 | src_hw != ME
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| 205 | if src_ip in request was not zero, check
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| 206 | also that it matches to dst_ip, otherwise
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| 207 | dst_ip/dst_hw do not matter.
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| 208 | */
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| 209 | if ((memcmp(p, &me.sll_addr, me.sll_halen) == 0)
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| 210 | || (src.s_addr && src.s_addr != dst_ip.s_addr))
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| 211 | return false;
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| 212 | }
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| 213 | if (!(option_mask32 & QUIET)) {
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| 214 | int s_printed = 0;
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| 215 |
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| 216 | printf("%scast re%s from %s [%s]",
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| 217 | FROM->sll_pkttype == PACKET_HOST ? "Uni" : "Broad",
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| 218 | ah->ar_op == htons(ARPOP_REPLY) ? "ply" : "quest",
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| 219 | inet_ntoa(src_ip),
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| 220 | ether_ntoa((struct ether_addr *) p));
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| 221 | if (dst_ip.s_addr != src.s_addr) {
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| 222 | printf("for %s ", inet_ntoa(dst_ip));
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| 223 | s_printed = 1;
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| 224 | }
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| 225 | if (memcmp(p + ah->ar_hln + 4, me.sll_addr, ah->ar_hln)) {
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| 226 | if (!s_printed)
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| 227 | printf("for ");
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| 228 | printf("[%s]",
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| 229 | ether_ntoa((struct ether_addr *) p + ah->ar_hln + 4));
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| 230 | }
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| 231 |
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| 232 | if (last) {
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| 233 | unsigned diff = MONOTONIC_US() - last;
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| 234 | printf(" %u.%03ums\n", diff / 1000, diff % 1000);
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| 235 | } else {
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| 236 | printf(" UNSOLICITED?\n");
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| 237 | }
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| 238 | fflush_all();
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| 239 | }
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| 240 | received++;
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| 241 | if (FROM->sll_pkttype != PACKET_HOST)
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| 242 | brd_recv++;
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| 243 | if (ah->ar_op == htons(ARPOP_REQUEST))
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| 244 | req_recv++;
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| 245 | if (option_mask32 & QUIT_ON_REPLY)
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| 246 | finish();
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| 247 | if (!(option_mask32 & BCAST_ONLY)) {
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| 248 | memcpy(he.sll_addr, p, me.sll_halen);
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| 249 | option_mask32 |= UNICASTING;
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| 250 | }
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| 251 | return true;
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| 252 | }
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| 253 |
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| 254 | int arping_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 255 | int arping_main(int argc UNUSED_PARAM, char **argv)
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| 256 | {
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| 257 | const char *device = "eth0";
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| 258 | char *source = NULL;
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| 259 | char *target;
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| 260 | unsigned char *packet;
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| 261 | char *err_str;
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| 262 |
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| 263 | INIT_G();
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| 264 |
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| 265 | sock_fd = xsocket(AF_PACKET, SOCK_DGRAM, 0);
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| 266 |
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| 267 | // Drop suid root privileges
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| 268 | // Need to remove SUID_NEVER from applets.h for this to work
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| 269 | //xsetuid(getuid());
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| 270 |
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| 271 | err_str = xasprintf("interface %s %%s", device);
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| 272 | {
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| 273 | unsigned opt;
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| 274 | char *str_timeout;
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| 275 |
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| 276 | /* Dad also sets quit_on_reply.
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| 277 | * Advert also sets unsolicited.
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| 278 | */
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| 279 | opt_complementary = "=1:Df:AU:c+";
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| 280 | opt = getopt32(argv, "DUAqfbc:w:I:s:",
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| 281 | &count, &str_timeout, &device, &source);
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| 282 | if (opt & 0x80) /* -w: timeout */
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| 283 | timeout_us = xatou_range(str_timeout, 0, INT_MAX/2000000) * 1000000 + 500000;
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| 284 | //if (opt & 0x200) /* -s: source */
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| 285 | option_mask32 &= 0x3f; /* set respective flags */
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| 286 | }
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| 287 |
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| 288 | target = argv[optind];
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| 289 |
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| 290 | xfunc_error_retval = 2;
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| 291 |
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| 292 | {
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| 293 | struct ifreq ifr;
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| 294 |
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| 295 | memset(&ifr, 0, sizeof(ifr));
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| 296 | strncpy_IFNAMSIZ(ifr.ifr_name, device);
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| 297 | /* We use ifr.ifr_name in error msg so that problem
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| 298 | * with truncated name will be visible */
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| 299 | ioctl_or_perror_and_die(sock_fd, SIOCGIFINDEX, &ifr, err_str, "not found");
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| 300 | me.sll_ifindex = ifr.ifr_ifindex;
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| 301 |
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| 302 | xioctl(sock_fd, SIOCGIFFLAGS, (char *) &ifr);
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| 303 |
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| 304 | if (!(ifr.ifr_flags & IFF_UP)) {
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| 305 | bb_error_msg_and_die(err_str, "is down");
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| 306 | }
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| 307 | if (ifr.ifr_flags & (IFF_NOARP | IFF_LOOPBACK)) {
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| 308 | bb_error_msg(err_str, "is not ARPable");
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| 309 | return (option_mask32 & DAD ? 0 : 2);
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| 310 | }
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| 311 | }
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| 312 |
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| 313 | /* if (!inet_aton(target, &dst)) - not needed */ {
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| 314 | len_and_sockaddr *lsa;
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| 315 | lsa = xhost_and_af2sockaddr(target, 0, AF_INET);
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| 316 | dst = lsa->u.sin.sin_addr;
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| 317 | if (ENABLE_FEATURE_CLEAN_UP)
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| 318 | free(lsa);
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| 319 | }
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| 320 |
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| 321 | if (source && !inet_aton(source, &src)) {
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| 322 | bb_error_msg_and_die("invalid source address %s", source);
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| 323 | }
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| 324 |
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| 325 | if ((option_mask32 & (DAD|UNSOLICITED)) == UNSOLICITED && src.s_addr == 0)
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| 326 | src = dst;
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| 327 |
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| 328 | if (!(option_mask32 & DAD) || src.s_addr) {
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| 329 | struct sockaddr_in saddr;
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| 330 | int probe_fd = xsocket(AF_INET, SOCK_DGRAM, 0);
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| 331 |
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| 332 | setsockopt_bindtodevice(probe_fd, device);
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| 333 | memset(&saddr, 0, sizeof(saddr));
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| 334 | saddr.sin_family = AF_INET;
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| 335 | if (src.s_addr) {
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| 336 | /* Check that this is indeed our IP */
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| 337 | saddr.sin_addr = src;
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| 338 | xbind(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
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| 339 | } else { /* !(option_mask32 & DAD) case */
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| 340 | /* Find IP address on this iface */
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| 341 | socklen_t alen = sizeof(saddr);
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| 342 |
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| 343 | saddr.sin_port = htons(1025);
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| 344 | saddr.sin_addr = dst;
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| 345 |
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| 346 | if (setsockopt(probe_fd, SOL_SOCKET, SO_DONTROUTE, &const_int_1, sizeof(const_int_1)) == -1)
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| 347 | bb_perror_msg("setsockopt(SO_DONTROUTE)");
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| 348 | xconnect(probe_fd, (struct sockaddr *) &saddr, sizeof(saddr));
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| 349 | getsockname(probe_fd, (struct sockaddr *) &saddr, &alen);
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| 350 | //never happens:
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| 351 | //if (getsockname(probe_fd, (struct sockaddr *) &saddr, &alen) == -1)
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| 352 | // bb_perror_msg_and_die("getsockname");
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| 353 | if (saddr.sin_family != AF_INET)
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| 354 | bb_error_msg_and_die("no IP address configured");
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| 355 | src = saddr.sin_addr;
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| 356 | }
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| 357 | close(probe_fd);
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| 358 | }
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| 359 |
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| 360 | me.sll_family = AF_PACKET;
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| 361 | //me.sll_ifindex = ifindex; - done before
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| 362 | me.sll_protocol = htons(ETH_P_ARP);
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| 363 | xbind(sock_fd, (struct sockaddr *) &me, sizeof(me));
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| 364 |
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| 365 | {
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| 366 | socklen_t alen = sizeof(me);
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| 367 | getsockname(sock_fd, (struct sockaddr *) &me, &alen);
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| 368 | //never happens:
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| 369 | //if (getsockname(sock_fd, (struct sockaddr *) &me, &alen) == -1)
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| 370 | // bb_perror_msg_and_die("getsockname");
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| 371 | }
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| 372 | if (me.sll_halen == 0) {
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| 373 | bb_error_msg(err_str, "is not ARPable (no ll address)");
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| 374 | return (option_mask32 & DAD ? 0 : 2);
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| 375 | }
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| 376 | he = me;
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| 377 | memset(he.sll_addr, -1, he.sll_halen);
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| 378 |
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| 379 | if (!(option_mask32 & QUIET)) {
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| 380 | /* inet_ntoa uses static storage, can't use in same printf */
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| 381 | printf("ARPING to %s", inet_ntoa(dst));
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| 382 | printf(" from %s via %s\n", inet_ntoa(src), device);
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| 383 | }
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| 384 |
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| 385 | signal_SA_RESTART_empty_mask(SIGINT, (void (*)(int))finish);
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| 386 | signal_SA_RESTART_empty_mask(SIGALRM, (void (*)(int))catcher);
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| 387 |
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| 388 | catcher();
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| 389 |
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| 390 | packet = xmalloc(4096);
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| 391 | while (1) {
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| 392 | sigset_t sset, osset;
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| 393 | struct sockaddr_ll from;
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| 394 | socklen_t alen = sizeof(from);
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| 395 | int cc;
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| 396 |
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| 397 | cc = recvfrom(sock_fd, packet, 4096, 0, (struct sockaddr *) &from, &alen);
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| 398 | if (cc < 0) {
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| 399 | bb_perror_msg("recvfrom");
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| 400 | continue;
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| 401 | }
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| 402 | sigemptyset(&sset);
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| 403 | sigaddset(&sset, SIGALRM);
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| 404 | sigaddset(&sset, SIGINT);
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| 405 | sigprocmask(SIG_BLOCK, &sset, &osset);
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| 406 | recv_pack(packet, cc, &from);
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| 407 | sigprocmask(SIG_SETMASK, &osset, NULL);
|
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| 408 | }
|
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| 409 | }
|
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