[3320] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * udhcp client
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| 4 | *
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| 5 | * Russ Dill <Russ.Dill@asu.edu> July 2001
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| 6 | *
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| 7 | * This program is free software; you can redistribute it and/or modify
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| 8 | * it under the terms of the GNU General Public License as published by
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| 9 | * the Free Software Foundation; either version 2 of the License, or
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| 10 | * (at your option) any later version.
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| 11 | *
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| 12 | * This program is distributed in the hope that it will be useful,
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| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 15 | * GNU General Public License for more details.
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| 16 | *
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| 17 | * You should have received a copy of the GNU General Public License
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| 18 | * along with this program; if not, write to the Free Software
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| 19 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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| 20 | */
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| 21 | #include <syslog.h>
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| 22 | /* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
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| 23 | #define WANT_PIDFILE 1
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| 24 | #include "common.h"
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| 25 | #include "dhcpd.h"
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| 26 | #include "dhcpc.h"
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| 27 |
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| 28 | #include <asm/types.h>
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| 29 | #if (defined(__GLIBC__) && __GLIBC__ >= 2 && __GLIBC_MINOR__ >= 1) || defined(_NEWLIB_VERSION)
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| 30 | # include <netpacket/packet.h>
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| 31 | # include <net/ethernet.h>
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| 32 | #else
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| 33 | # include <linux/if_packet.h>
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| 34 | # include <linux/if_ether.h>
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| 35 | #endif
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| 36 | #include <linux/filter.h>
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| 37 |
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| 38 | /* struct client_config_t client_config is in bb_common_bufsiz1 */
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| 39 |
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| 40 |
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| 41 | /*** Script execution code ***/
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| 42 |
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| 43 | /* get a rough idea of how long an option will be (rounding up...) */
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| 44 | static const uint8_t len_of_option_as_string[] = {
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| 45 | [OPTION_IP ] = sizeof("255.255.255.255 "),
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| 46 | [OPTION_IP_PAIR ] = sizeof("255.255.255.255 ") * 2,
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| 47 | [OPTION_STATIC_ROUTES ] = sizeof("255.255.255.255/32 255.255.255.255 "),
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| 48 | [OPTION_STRING ] = 1,
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| 49 | #if ENABLE_FEATURE_UDHCP_RFC3397
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| 50 | [OPTION_DNS_STRING ] = 1, /* unused */
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| 51 | /* Hmmm, this severely overestimates size if SIP_SERVERS option
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| 52 | * is in domain name form: N-byte option in binary form
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| 53 | * mallocs ~16*N bytes. But it is freed almost at once.
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| 54 | */
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| 55 | [OPTION_SIP_SERVERS ] = sizeof("255.255.255.255 "),
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| 56 | #endif
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| 57 | // [OPTION_BOOLEAN ] = sizeof("yes "),
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| 58 | [OPTION_U8 ] = sizeof("255 "),
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| 59 | [OPTION_U16 ] = sizeof("65535 "),
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| 60 | // [OPTION_S16 ] = sizeof("-32768 "),
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| 61 | [OPTION_U32 ] = sizeof("4294967295 "),
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| 62 | [OPTION_S32 ] = sizeof("-2147483684 "),
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| 63 | };
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| 64 |
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| 65 | /* note: ip is a pointer to an IP in network order, possibly misaliged */
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| 66 | static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
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| 67 | {
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| 68 | return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
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| 69 | }
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| 70 |
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| 71 | /* really simple implementation, just count the bits */
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| 72 | static int mton(uint32_t mask)
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| 73 | {
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| 74 | int i = 0;
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| 75 | mask = ntohl(mask); /* 111110000-like bit pattern */
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| 76 | while (mask) {
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| 77 | i++;
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| 78 | mask <<= 1;
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| 79 | }
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| 80 | return i;
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| 81 | }
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| 82 |
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| 83 | /* Create "opt_name=opt_value" string */
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| 84 | static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_optflag *optflag, const char *opt_name)
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| 85 | {
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| 86 | unsigned upper_length;
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| 87 | int len, type, optlen;
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| 88 | char *dest, *ret;
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| 89 |
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| 90 | /* option points to OPT_DATA, need to go back and get OPT_LEN */
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| 91 | len = option[OPT_LEN - OPT_DATA];
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| 92 |
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| 93 | type = optflag->flags & OPTION_TYPE_MASK;
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| 94 | optlen = dhcp_option_lengths[type];
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| 95 | upper_length = len_of_option_as_string[type] * ((unsigned)len / (unsigned)optlen);
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| 96 |
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| 97 | dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
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| 98 | dest += sprintf(ret, "%s=", opt_name);
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| 99 |
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| 100 | while (len >= optlen) {
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| 101 | unsigned ip_ofs = 0;
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| 102 |
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| 103 | switch (type) {
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| 104 | case OPTION_IP_PAIR:
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| 105 | dest += sprint_nip(dest, "", option);
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| 106 | *dest++ = '/';
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| 107 | ip_ofs = 4;
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| 108 | /* fall through */
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| 109 | case OPTION_IP:
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| 110 | dest += sprint_nip(dest, "", option + ip_ofs);
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| 111 | break;
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| 112 | // case OPTION_BOOLEAN:
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| 113 | // dest += sprintf(dest, *option ? "yes" : "no");
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| 114 | // break;
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| 115 | case OPTION_U8:
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| 116 | dest += sprintf(dest, "%u", *option);
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| 117 | break;
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| 118 | // case OPTION_S16:
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| 119 | case OPTION_U16: {
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| 120 | uint16_t val_u16;
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| 121 | move_from_unaligned16(val_u16, option);
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| 122 | dest += sprintf(dest, "%u", ntohs(val_u16));
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| 123 | break;
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| 124 | }
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| 125 | case OPTION_S32:
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| 126 | case OPTION_U32: {
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| 127 | uint32_t val_u32;
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| 128 | move_from_unaligned32(val_u32, option);
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| 129 | dest += sprintf(dest, type == OPTION_U32 ? "%lu" : "%ld", (unsigned long) ntohl(val_u32));
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| 130 | break;
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| 131 | }
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| 132 | case OPTION_STRING:
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| 133 | memcpy(dest, option, len);
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| 134 | dest[len] = '\0';
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| 135 | return ret; /* Short circuit this case */
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| 136 | case OPTION_STATIC_ROUTES: {
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| 137 | /* Option binary format:
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| 138 | * mask [one byte, 0..32]
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| 139 | * ip [big endian, 0..4 bytes depending on mask]
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| 140 | * router [big endian, 4 bytes]
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| 141 | * may be repeated
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| 142 | *
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| 143 | * We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
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| 144 | */
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| 145 | const char *pfx = "";
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| 146 |
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| 147 | while (len >= 1 + 4) { /* mask + 0-byte ip + router */
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| 148 | uint32_t nip;
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| 149 | uint8_t *p;
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| 150 | unsigned mask;
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| 151 | int bytes;
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| 152 |
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| 153 | mask = *option++;
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| 154 | if (mask > 32)
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| 155 | break;
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| 156 | len--;
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| 157 |
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| 158 | nip = 0;
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| 159 | p = (void*) &nip;
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| 160 | bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
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| 161 | while (--bytes >= 0) {
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| 162 | *p++ = *option++;
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| 163 | len--;
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| 164 | }
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| 165 | if (len < 4)
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| 166 | break;
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| 167 |
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| 168 | /* print ip/mask */
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| 169 | dest += sprint_nip(dest, pfx, (void*) &nip);
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| 170 | pfx = " ";
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| 171 | dest += sprintf(dest, "/%u ", mask);
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| 172 | /* print router */
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| 173 | dest += sprint_nip(dest, "", option);
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| 174 | option += 4;
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| 175 | len -= 4;
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| 176 | }
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| 177 |
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| 178 | return ret;
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| 179 | }
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| 180 | #if ENABLE_FEATURE_UDHCP_RFC3397
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| 181 | case OPTION_DNS_STRING:
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| 182 | /* unpack option into dest; use ret for prefix (i.e., "optname=") */
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| 183 | dest = dname_dec(option, len, ret);
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| 184 | if (dest) {
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| 185 | free(ret);
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| 186 | return dest;
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| 187 | }
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| 188 | /* error. return "optname=" string */
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| 189 | return ret;
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| 190 | case OPTION_SIP_SERVERS:
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| 191 | /* Option binary format:
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| 192 | * type: byte
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| 193 | * type=0: domain names, dns-compressed
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| 194 | * type=1: IP addrs
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| 195 | */
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| 196 | option++;
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| 197 | len--;
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| 198 | if (option[-1] == 0) {
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| 199 | dest = dname_dec(option, len, ret);
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| 200 | if (dest) {
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| 201 | free(ret);
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| 202 | return dest;
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| 203 | }
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| 204 | } else
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| 205 | if (option[-1] == 1) {
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| 206 | const char *pfx = "";
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| 207 | while (1) {
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| 208 | len -= 4;
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| 209 | if (len < 0)
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| 210 | break;
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| 211 | dest += sprint_nip(dest, pfx, option);
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| 212 | pfx = " ";
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| 213 | option += 4;
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| 214 | }
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| 215 | }
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| 216 | return ret;
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| 217 | #endif
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| 218 | } /* switch */
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| 219 | option += optlen;
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| 220 | len -= optlen;
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| 221 | // TODO: it can be a list only if (optflag->flags & OPTION_LIST).
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| 222 | // Should we bail out/warn if we see multi-ip option which is
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| 223 | // not allowed to be such (for example, DHCP_BROADCAST)? -
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| 224 | if (len <= 0 /* || !(optflag->flags & OPTION_LIST) */)
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| 225 | break;
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| 226 | *dest++ = ' ';
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| 227 | *dest = '\0';
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| 228 | }
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| 229 | return ret;
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| 230 | }
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| 231 |
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| 232 | /* put all the parameters into the environment */
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| 233 | static char **fill_envp(struct dhcp_packet *packet)
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| 234 | {
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| 235 | int envc;
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| 236 | int i;
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| 237 | char **envp, **curr;
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| 238 | const char *opt_name;
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| 239 | uint8_t *temp;
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| 240 | uint8_t overload = 0;
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| 241 |
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| 242 | /* We need 6 elements for:
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| 243 | * "interface=IFACE"
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| 244 | * "ip=N.N.N.N" from packet->yiaddr
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| 245 | * "siaddr=IP" from packet->siaddr_nip (unless 0)
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| 246 | * "boot_file=FILE" from packet->file (unless overloaded)
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| 247 | * "sname=SERVER_HOSTNAME" from packet->sname (unless overloaded)
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| 248 | * terminating NULL
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| 249 | */
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| 250 | envc = 6;
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| 251 | /* +1 element for each option, +2 for subnet option: */
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| 252 | if (packet) {
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| 253 | for (i = 0; dhcp_optflags[i].code; i++) {
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| 254 | if (udhcp_get_option(packet, dhcp_optflags[i].code)) {
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| 255 | if (dhcp_optflags[i].code == DHCP_SUBNET)
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| 256 | envc++; /* for mton */
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| 257 | envc++;
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| 258 | }
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| 259 | }
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| 260 | temp = udhcp_get_option(packet, DHCP_OPTION_OVERLOAD);
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| 261 | if (temp)
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| 262 | overload = *temp;
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| 263 | }
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| 264 | curr = envp = xzalloc(sizeof(char *) * envc);
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| 265 |
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| 266 | *curr = xasprintf("interface=%s", client_config.interface);
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| 267 | putenv(*curr++);
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| 268 |
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| 269 | if (!packet)
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| 270 | return envp;
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| 271 |
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| 272 | *curr = xmalloc(sizeof("ip=255.255.255.255"));
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| 273 | sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr);
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| 274 | putenv(*curr++);
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| 275 |
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| 276 | opt_name = dhcp_option_strings;
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| 277 | i = 0;
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| 278 | while (*opt_name) {
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| 279 | temp = udhcp_get_option(packet, dhcp_optflags[i].code);
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| 280 | if (!temp)
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| 281 | goto next;
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| 282 | *curr = xmalloc_optname_optval(temp, &dhcp_optflags[i], opt_name);
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| 283 | putenv(*curr++);
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| 284 | if (dhcp_optflags[i].code == DHCP_SUBNET) {
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| 285 | /* Subnet option: make things like "$ip/$mask" possible */
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| 286 | uint32_t subnet;
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| 287 | move_from_unaligned32(subnet, temp);
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| 288 | *curr = xasprintf("mask=%d", mton(subnet));
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| 289 | putenv(*curr++);
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| 290 | }
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| 291 | next:
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| 292 | opt_name += strlen(opt_name) + 1;
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| 293 | i++;
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| 294 | }
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| 295 | if (packet->siaddr_nip) {
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| 296 | *curr = xmalloc(sizeof("siaddr=255.255.255.255"));
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| 297 | sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip);
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| 298 | putenv(*curr++);
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| 299 | }
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| 300 | if (!(overload & FILE_FIELD) && packet->file[0]) {
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| 301 | /* watch out for invalid packets */
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| 302 | *curr = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file);
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| 303 | putenv(*curr++);
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| 304 | }
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| 305 | if (!(overload & SNAME_FIELD) && packet->sname[0]) {
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| 306 | /* watch out for invalid packets */
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| 307 | *curr = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname);
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| 308 | putenv(*curr++);
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| 309 | }
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| 310 | return envp;
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| 311 | }
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| 312 |
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| 313 | /* Call a script with a par file and env vars */
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| 314 | static void udhcp_run_script(struct dhcp_packet *packet, const char *name)
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| 315 | {
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| 316 | char **envp, **curr;
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| 317 | char *argv[3];
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| 318 |
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| 319 | if (client_config.script == NULL)
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| 320 | return;
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| 321 |
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| 322 | envp = fill_envp(packet);
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| 323 |
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| 324 | /* call script */
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| 325 | log1("Executing %s %s", client_config.script, name);
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| 326 | argv[0] = (char*) client_config.script;
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| 327 | argv[1] = (char*) name;
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| 328 | argv[2] = NULL;
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| 329 | spawn_and_wait(argv);
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| 330 |
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| 331 | for (curr = envp; *curr; curr++) {
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| 332 | log2(" %s", *curr);
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| 333 | bb_unsetenv_and_free(*curr);
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| 334 | }
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| 335 | free(envp);
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| 336 | }
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| 337 |
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| 338 |
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| 339 | /*** Sending/receiving packets ***/
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| 340 |
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| 341 | static ALWAYS_INLINE uint32_t random_xid(void)
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| 342 | {
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| 343 | return rand();
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| 344 | }
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| 345 |
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| 346 | /* Initialize the packet with the proper defaults */
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| 347 | static void init_packet(struct dhcp_packet *packet, char type)
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| 348 | {
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| 349 | /* Fill in: op, htype, hlen, cookie fields; message type option: */
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| 350 | udhcp_init_header(packet, type);
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| 351 |
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| 352 | packet->xid = random_xid();
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| 353 |
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| 354 | memcpy(packet->chaddr, client_config.client_mac, 6);
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| 355 | if (client_config.clientid)
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| 356 | udhcp_add_binary_option(packet, client_config.clientid);
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| 357 | }
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| 358 |
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| 359 | static void add_client_options(struct dhcp_packet *packet)
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| 360 | {
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| 361 | uint8_t c;
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| 362 | int i, end, len;
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| 363 |
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| 364 | udhcp_add_simple_option(packet, DHCP_MAX_SIZE, htons(IP_UDP_DHCP_SIZE));
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| 365 |
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| 366 | /* Add a "param req" option with the list of options we'd like to have
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| 367 | * from stubborn DHCP servers. Pull the data from the struct in common.c.
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| 368 | * No bounds checking because it goes towards the head of the packet. */
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| 369 | end = udhcp_end_option(packet->options);
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| 370 | len = 0;
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| 371 | for (i = 0; (c = dhcp_optflags[i].code) != 0; i++) {
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| 372 | if (( (dhcp_optflags[i].flags & OPTION_REQ)
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| 373 | && !client_config.no_default_options
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| 374 | )
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| 375 | || (client_config.opt_mask[c >> 3] & (1 << (c & 7)))
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| 376 | ) {
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| 377 | packet->options[end + OPT_DATA + len] = c;
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| 378 | len++;
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| 379 | }
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| 380 | }
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| 381 | if (len) {
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| 382 | packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
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| 383 | packet->options[end + OPT_LEN] = len;
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| 384 | packet->options[end + OPT_DATA + len] = DHCP_END;
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| 385 | }
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| 386 |
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| 387 | if (client_config.vendorclass)
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| 388 | udhcp_add_binary_option(packet, client_config.vendorclass);
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| 389 | if (client_config.hostname)
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| 390 | udhcp_add_binary_option(packet, client_config.hostname);
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| 391 | if (client_config.fqdn)
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| 392 | udhcp_add_binary_option(packet, client_config.fqdn);
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| 393 |
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| 394 | /* Add -x options if any */
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| 395 | {
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| 396 | struct option_set *curr = client_config.options;
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| 397 | while (curr) {
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| 398 | udhcp_add_binary_option(packet, curr->data);
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| 399 | curr = curr->next;
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| 400 | }
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| 401 | // if (client_config.sname)
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| 402 | // strncpy((char*)packet->sname, client_config.sname, sizeof(packet->sname) - 1);
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| 403 | // if (client_config.boot_file)
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| 404 | // strncpy((char*)packet->file, client_config.boot_file, sizeof(packet->file) - 1);
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| 405 | }
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| 406 | }
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| 407 |
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| 408 | /* RFC 2131
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| 409 | * 4.4.4 Use of broadcast and unicast
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| 410 | *
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| 411 | * The DHCP client broadcasts DHCPDISCOVER, DHCPREQUEST and DHCPINFORM
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| 412 | * messages, unless the client knows the address of a DHCP server.
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| 413 | * The client unicasts DHCPRELEASE messages to the server. Because
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| 414 | * the client is declining the use of the IP address supplied by the server,
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| 415 | * the client broadcasts DHCPDECLINE messages.
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| 416 | *
|
---|
| 417 | * When the DHCP client knows the address of a DHCP server, in either
|
---|
| 418 | * INIT or REBOOTING state, the client may use that address
|
---|
| 419 | * in the DHCPDISCOVER or DHCPREQUEST rather than the IP broadcast address.
|
---|
| 420 | * The client may also use unicast to send DHCPINFORM messages
|
---|
| 421 | * to a known DHCP server. If the client receives no response to DHCP
|
---|
| 422 | * messages sent to the IP address of a known DHCP server, the DHCP
|
---|
| 423 | * client reverts to using the IP broadcast address.
|
---|
| 424 | */
|
---|
| 425 |
|
---|
| 426 | static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet)
|
---|
| 427 | {
|
---|
| 428 | return udhcp_send_raw_packet(packet,
|
---|
| 429 | /*src*/ INADDR_ANY, CLIENT_PORT,
|
---|
| 430 | /*dst*/ INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR,
|
---|
| 431 | client_config.ifindex);
|
---|
| 432 | }
|
---|
| 433 |
|
---|
| 434 | /* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
|
---|
| 435 | /* NOINLINE: limit stack usage in caller */
|
---|
| 436 | static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
|
---|
| 437 | {
|
---|
| 438 | struct dhcp_packet packet;
|
---|
| 439 |
|
---|
| 440 | /* Fill in: op, htype, hlen, cookie, chaddr fields,
|
---|
| 441 | * random xid field (we override it below),
|
---|
| 442 | * client-id option (unless -C), message type option:
|
---|
| 443 | */
|
---|
| 444 | init_packet(&packet, DHCPDISCOVER);
|
---|
| 445 |
|
---|
| 446 | packet.xid = xid;
|
---|
| 447 | if (requested)
|
---|
| 448 | udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
|
---|
| 449 |
|
---|
| 450 | /* Add options: maxsize,
|
---|
| 451 | * optionally: hostname, fqdn, vendorclass,
|
---|
| 452 | * "param req" option according to -O, options specified with -x
|
---|
| 453 | */
|
---|
| 454 | add_client_options(&packet);
|
---|
| 455 |
|
---|
| 456 | bb_info_msg("Sending discover...");
|
---|
| 457 | return raw_bcast_from_client_config_ifindex(&packet);
|
---|
| 458 | }
|
---|
| 459 |
|
---|
| 460 | /* Broadcast a DHCP request message */
|
---|
| 461 | /* RFC 2131 3.1 paragraph 3:
|
---|
| 462 | * "The client _broadcasts_ a DHCPREQUEST message..."
|
---|
| 463 | */
|
---|
| 464 | /* NOINLINE: limit stack usage in caller */
|
---|
| 465 | static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requested)
|
---|
| 466 | {
|
---|
| 467 | struct dhcp_packet packet;
|
---|
| 468 | struct in_addr addr;
|
---|
| 469 |
|
---|
| 470 | /*
|
---|
| 471 | * RFC 2131 4.3.2 DHCPREQUEST message
|
---|
| 472 | * ...
|
---|
| 473 | * If the DHCPREQUEST message contains a 'server identifier'
|
---|
| 474 | * option, the message is in response to a DHCPOFFER message.
|
---|
| 475 | * Otherwise, the message is a request to verify or extend an
|
---|
| 476 | * existing lease. If the client uses a 'client identifier'
|
---|
| 477 | * in a DHCPREQUEST message, it MUST use that same 'client identifier'
|
---|
| 478 | * in all subsequent messages. If the client included a list
|
---|
| 479 | * of requested parameters in a DHCPDISCOVER message, it MUST
|
---|
| 480 | * include that list in all subsequent messages.
|
---|
| 481 | */
|
---|
| 482 | /* Fill in: op, htype, hlen, cookie, chaddr fields,
|
---|
| 483 | * random xid field (we override it below),
|
---|
| 484 | * client-id option (unless -C), message type option:
|
---|
| 485 | */
|
---|
| 486 | init_packet(&packet, DHCPREQUEST);
|
---|
| 487 |
|
---|
| 488 | packet.xid = xid;
|
---|
| 489 | udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
|
---|
| 490 |
|
---|
| 491 | udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
|
---|
| 492 |
|
---|
| 493 | /* Add options: maxsize,
|
---|
| 494 | * optionally: hostname, fqdn, vendorclass,
|
---|
| 495 | * "param req" option according to -O, and options specified with -x
|
---|
| 496 | */
|
---|
| 497 | add_client_options(&packet);
|
---|
| 498 |
|
---|
| 499 | addr.s_addr = requested;
|
---|
| 500 | bb_info_msg("Sending select for %s...", inet_ntoa(addr));
|
---|
| 501 | return raw_bcast_from_client_config_ifindex(&packet);
|
---|
| 502 | }
|
---|
| 503 |
|
---|
| 504 | /* Unicast or broadcast a DHCP renew message */
|
---|
| 505 | /* NOINLINE: limit stack usage in caller */
|
---|
| 506 | static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
|
---|
| 507 | {
|
---|
| 508 | struct dhcp_packet packet;
|
---|
| 509 |
|
---|
| 510 | /*
|
---|
| 511 | * RFC 2131 4.3.2 DHCPREQUEST message
|
---|
| 512 | * ...
|
---|
| 513 | * DHCPREQUEST generated during RENEWING state:
|
---|
| 514 | *
|
---|
| 515 | * 'server identifier' MUST NOT be filled in, 'requested IP address'
|
---|
| 516 | * option MUST NOT be filled in, 'ciaddr' MUST be filled in with
|
---|
| 517 | * client's IP address. In this situation, the client is completely
|
---|
| 518 | * configured, and is trying to extend its lease. This message will
|
---|
| 519 | * be unicast, so no relay agents will be involved in its
|
---|
| 520 | * transmission. Because 'giaddr' is therefore not filled in, the
|
---|
| 521 | * DHCP server will trust the value in 'ciaddr', and use it when
|
---|
| 522 | * replying to the client.
|
---|
| 523 | */
|
---|
| 524 | /* Fill in: op, htype, hlen, cookie, chaddr fields,
|
---|
| 525 | * random xid field (we override it below),
|
---|
| 526 | * client-id option (unless -C), message type option:
|
---|
| 527 | */
|
---|
| 528 | init_packet(&packet, DHCPREQUEST);
|
---|
| 529 |
|
---|
| 530 | packet.xid = xid;
|
---|
| 531 | packet.ciaddr = ciaddr;
|
---|
| 532 |
|
---|
| 533 | /* Add options: maxsize,
|
---|
| 534 | * optionally: hostname, fqdn, vendorclass,
|
---|
| 535 | * "param req" option according to -O, and options specified with -x
|
---|
| 536 | */
|
---|
| 537 | add_client_options(&packet);
|
---|
| 538 |
|
---|
| 539 | bb_info_msg("Sending renew...");
|
---|
| 540 | if (server)
|
---|
| 541 | return udhcp_send_kernel_packet(&packet,
|
---|
| 542 | ciaddr, CLIENT_PORT,
|
---|
| 543 | server, SERVER_PORT);
|
---|
| 544 | return raw_bcast_from_client_config_ifindex(&packet);
|
---|
| 545 | }
|
---|
| 546 |
|
---|
| 547 | #if ENABLE_FEATURE_UDHCPC_ARPING
|
---|
| 548 | /* Broadcast a DHCP decline message */
|
---|
| 549 | /* NOINLINE: limit stack usage in caller */
|
---|
| 550 | static NOINLINE int send_decline(uint32_t xid, uint32_t server, uint32_t requested)
|
---|
| 551 | {
|
---|
| 552 | struct dhcp_packet packet;
|
---|
| 553 |
|
---|
| 554 | /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
|
---|
| 555 | * client-id option (unless -C), message type option:
|
---|
| 556 | */
|
---|
| 557 | init_packet(&packet, DHCPDECLINE);
|
---|
| 558 |
|
---|
| 559 | /* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
|
---|
| 560 | * but in case the server is buggy and wants DHCPDECLINE's xid
|
---|
| 561 | * to match the xid which started entire handshake,
|
---|
| 562 | * we use the same xid we used in initial DHCPDISCOVER:
|
---|
| 563 | */
|
---|
| 564 | packet.xid = xid;
|
---|
| 565 | /* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
|
---|
| 566 | udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
|
---|
| 567 |
|
---|
| 568 | udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
|
---|
| 569 |
|
---|
| 570 | bb_info_msg("Sending decline...");
|
---|
| 571 | return raw_bcast_from_client_config_ifindex(&packet);
|
---|
| 572 | }
|
---|
| 573 | #endif
|
---|
| 574 |
|
---|
| 575 | /* Unicast a DHCP release message */
|
---|
| 576 | static int send_release(uint32_t server, uint32_t ciaddr)
|
---|
| 577 | {
|
---|
| 578 | struct dhcp_packet packet;
|
---|
| 579 |
|
---|
| 580 | /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
|
---|
| 581 | * client-id option (unless -C), message type option:
|
---|
| 582 | */
|
---|
| 583 | init_packet(&packet, DHCPRELEASE);
|
---|
| 584 |
|
---|
| 585 | /* DHCPRELEASE uses ciaddr, not "requested ip", to store IP being released */
|
---|
| 586 | packet.ciaddr = ciaddr;
|
---|
| 587 |
|
---|
| 588 | udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
|
---|
| 589 |
|
---|
| 590 | bb_info_msg("Sending release...");
|
---|
| 591 | return udhcp_send_kernel_packet(&packet, ciaddr, CLIENT_PORT, server, SERVER_PORT);
|
---|
| 592 | }
|
---|
| 593 |
|
---|
| 594 | /* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */
|
---|
| 595 | /* NOINLINE: limit stack usage in caller */
|
---|
| 596 | static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
|
---|
| 597 | {
|
---|
| 598 | int bytes;
|
---|
| 599 | struct ip_udp_dhcp_packet packet;
|
---|
| 600 | uint16_t check;
|
---|
| 601 |
|
---|
| 602 | memset(&packet, 0, sizeof(packet));
|
---|
| 603 | bytes = safe_read(fd, &packet, sizeof(packet));
|
---|
| 604 | if (bytes < 0) {
|
---|
| 605 | log1("Packet read error, ignoring");
|
---|
| 606 | /* NB: possible down interface, etc. Caller should pause. */
|
---|
| 607 | return bytes; /* returns -1 */
|
---|
| 608 | }
|
---|
| 609 |
|
---|
| 610 | if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) {
|
---|
| 611 | log1("Packet is too short, ignoring");
|
---|
| 612 | return -2;
|
---|
| 613 | }
|
---|
| 614 |
|
---|
| 615 | if (bytes < ntohs(packet.ip.tot_len)) {
|
---|
| 616 | /* packet is bigger than sizeof(packet), we did partial read */
|
---|
| 617 | log1("Oversized packet, ignoring");
|
---|
| 618 | return -2;
|
---|
| 619 | }
|
---|
| 620 |
|
---|
| 621 | /* ignore any extra garbage bytes */
|
---|
| 622 | bytes = ntohs(packet.ip.tot_len);
|
---|
| 623 |
|
---|
| 624 | /* make sure its the right packet for us, and that it passes sanity checks */
|
---|
| 625 | if (packet.ip.protocol != IPPROTO_UDP || packet.ip.version != IPVERSION
|
---|
| 626 | || packet.ip.ihl != (sizeof(packet.ip) >> 2)
|
---|
| 627 | || packet.udp.dest != htons(CLIENT_PORT)
|
---|
| 628 | /* || bytes > (int) sizeof(packet) - can't happen */
|
---|
| 629 | || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip))
|
---|
| 630 | ) {
|
---|
| 631 | log1("Unrelated/bogus packet, ignoring");
|
---|
| 632 | return -2;
|
---|
| 633 | }
|
---|
| 634 |
|
---|
| 635 | /* verify IP checksum */
|
---|
| 636 | check = packet.ip.check;
|
---|
| 637 | packet.ip.check = 0;
|
---|
| 638 | if (check != udhcp_checksum(&packet.ip, sizeof(packet.ip))) {
|
---|
| 639 | log1("Bad IP header checksum, ignoring");
|
---|
| 640 | return -2;
|
---|
| 641 | }
|
---|
| 642 |
|
---|
| 643 | /* verify UDP checksum. IP header has to be modified for this */
|
---|
| 644 | memset(&packet.ip, 0, offsetof(struct iphdr, protocol));
|
---|
| 645 | /* ip.xx fields which are not memset: protocol, check, saddr, daddr */
|
---|
| 646 | packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
|
---|
| 647 | check = packet.udp.check;
|
---|
| 648 | packet.udp.check = 0;
|
---|
| 649 | if (check && check != udhcp_checksum(&packet, bytes)) {
|
---|
| 650 | log1("Packet with bad UDP checksum received, ignoring");
|
---|
| 651 | return -2;
|
---|
| 652 | }
|
---|
| 653 |
|
---|
| 654 | memcpy(dhcp_pkt, &packet.data, bytes - (sizeof(packet.ip) + sizeof(packet.udp)));
|
---|
| 655 |
|
---|
| 656 | if (dhcp_pkt->cookie != htonl(DHCP_MAGIC)) {
|
---|
| 657 | bb_info_msg("Packet with bad magic, ignoring");
|
---|
| 658 | return -2;
|
---|
| 659 | }
|
---|
| 660 | log1("Got valid DHCP packet");
|
---|
| 661 | udhcp_dump_packet(dhcp_pkt);
|
---|
| 662 | return bytes - (sizeof(packet.ip) + sizeof(packet.udp));
|
---|
| 663 | }
|
---|
| 664 |
|
---|
| 665 |
|
---|
| 666 | /*** Main ***/
|
---|
| 667 |
|
---|
| 668 | static int sockfd = -1;
|
---|
| 669 |
|
---|
| 670 | #define LISTEN_NONE 0
|
---|
| 671 | #define LISTEN_KERNEL 1
|
---|
| 672 | #define LISTEN_RAW 2
|
---|
| 673 | static smallint listen_mode;
|
---|
| 674 |
|
---|
| 675 | /* initial state: (re)start DHCP negotiation */
|
---|
| 676 | #define INIT_SELECTING 0
|
---|
| 677 | /* discover was sent, DHCPOFFER reply received */
|
---|
| 678 | #define REQUESTING 1
|
---|
| 679 | /* select/renew was sent, DHCPACK reply received */
|
---|
| 680 | #define BOUND 2
|
---|
| 681 | /* half of lease passed, want to renew it by sending unicast renew requests */
|
---|
| 682 | #define RENEWING 3
|
---|
| 683 | /* renew requests were not answered, lease is almost over, send broadcast renew */
|
---|
| 684 | #define REBINDING 4
|
---|
| 685 | /* manually requested renew (SIGUSR1) */
|
---|
| 686 | #define RENEW_REQUESTED 5
|
---|
| 687 | /* release, possibly manually requested (SIGUSR2) */
|
---|
| 688 | #define RELEASED 6
|
---|
| 689 | static smallint state;
|
---|
| 690 |
|
---|
| 691 | static int udhcp_raw_socket(int ifindex)
|
---|
| 692 | {
|
---|
| 693 | int fd;
|
---|
| 694 | struct sockaddr_ll sock;
|
---|
| 695 |
|
---|
| 696 | /*
|
---|
| 697 | * Comment:
|
---|
| 698 | *
|
---|
| 699 | * I've selected not to see LL header, so BPF doesn't see it, too.
|
---|
| 700 | * The filter may also pass non-IP and non-ARP packets, but we do
|
---|
| 701 | * a more complete check when receiving the message in userspace.
|
---|
| 702 | *
|
---|
| 703 | * and filter shamelessly stolen from:
|
---|
| 704 | *
|
---|
| 705 | * http://www.flamewarmaster.de/software/dhcpclient/
|
---|
| 706 | *
|
---|
| 707 | * There are a few other interesting ideas on that page (look under
|
---|
| 708 | * "Motivation"). Use of netlink events is most interesting. Think
|
---|
| 709 | * of various network servers listening for events and reconfiguring.
|
---|
| 710 | * That would obsolete sending HUP signals and/or make use of restarts.
|
---|
| 711 | *
|
---|
| 712 | * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
|
---|
| 713 | * License: GPL v2.
|
---|
| 714 | *
|
---|
| 715 | * TODO: make conditional?
|
---|
| 716 | */
|
---|
| 717 | #define SERVER_AND_CLIENT_PORTS ((67 << 16) + 68)
|
---|
| 718 | static const struct sock_filter filter_instr[] = {
|
---|
| 719 | /* check for udp */
|
---|
| 720 | BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
|
---|
| 721 | BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 2, 0), /* L5, L1, is UDP? */
|
---|
| 722 | /* ugly check for arp on ethernet-like and IPv4 */
|
---|
| 723 | BPF_STMT(BPF_LD|BPF_W|BPF_ABS, 2), /* L1: */
|
---|
| 724 | BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 0x08000604, 3, 4), /* L3, L4 */
|
---|
| 725 | /* skip IP header */
|
---|
| 726 | BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0), /* L5: */
|
---|
| 727 | /* check udp source and destination ports */
|
---|
| 728 | BPF_STMT(BPF_LD|BPF_W|BPF_IND, 0),
|
---|
| 729 | BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, SERVER_AND_CLIENT_PORTS, 0, 1), /* L3, L4 */
|
---|
| 730 | /* returns */
|
---|
| 731 | BPF_STMT(BPF_RET|BPF_K, 0x0fffffff ), /* L3: pass */
|
---|
| 732 | BPF_STMT(BPF_RET|BPF_K, 0), /* L4: reject */
|
---|
| 733 | };
|
---|
| 734 | static const struct sock_fprog filter_prog = {
|
---|
| 735 | .len = sizeof(filter_instr) / sizeof(filter_instr[0]),
|
---|
| 736 | /* casting const away: */
|
---|
| 737 | .filter = (struct sock_filter *) filter_instr,
|
---|
| 738 | };
|
---|
| 739 |
|
---|
| 740 | log1("Opening raw socket on ifindex %d", ifindex); //log2?
|
---|
| 741 |
|
---|
| 742 | fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
|
---|
| 743 | log1("Got raw socket fd %d", fd); //log2?
|
---|
| 744 |
|
---|
| 745 | if (SERVER_PORT == 67 && CLIENT_PORT == 68) {
|
---|
| 746 | /* Use only if standard ports are in use */
|
---|
| 747 | /* Ignoring error (kernel may lack support for this) */
|
---|
| 748 | if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
|
---|
| 749 | sizeof(filter_prog)) >= 0)
|
---|
| 750 | log1("Attached filter to raw socket fd %d", fd); // log?
|
---|
| 751 | }
|
---|
| 752 |
|
---|
| 753 | sock.sll_family = AF_PACKET;
|
---|
| 754 | sock.sll_protocol = htons(ETH_P_IP);
|
---|
| 755 | sock.sll_ifindex = ifindex;
|
---|
| 756 | xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
|
---|
| 757 | log1("Created raw socket");
|
---|
| 758 |
|
---|
| 759 | return fd;
|
---|
| 760 | }
|
---|
| 761 |
|
---|
| 762 | static void change_listen_mode(int new_mode)
|
---|
| 763 | {
|
---|
| 764 | log1("Entering listen mode: %s",
|
---|
| 765 | new_mode != LISTEN_NONE
|
---|
| 766 | ? (new_mode == LISTEN_KERNEL ? "kernel" : "raw")
|
---|
| 767 | : "none"
|
---|
| 768 | );
|
---|
| 769 |
|
---|
| 770 | listen_mode = new_mode;
|
---|
| 771 | if (sockfd >= 0) {
|
---|
| 772 | close(sockfd);
|
---|
| 773 | sockfd = -1;
|
---|
| 774 | }
|
---|
| 775 | if (new_mode == LISTEN_KERNEL)
|
---|
| 776 | sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
|
---|
| 777 | else if (new_mode != LISTEN_NONE)
|
---|
| 778 | sockfd = udhcp_raw_socket(client_config.ifindex);
|
---|
| 779 | /* else LISTEN_NONE: sockfd stays closed */
|
---|
| 780 | }
|
---|
| 781 |
|
---|
| 782 | static void perform_renew(void)
|
---|
| 783 | {
|
---|
| 784 | bb_info_msg("Performing a DHCP renew");
|
---|
| 785 | switch (state) {
|
---|
| 786 | case BOUND:
|
---|
| 787 | change_listen_mode(LISTEN_KERNEL);
|
---|
| 788 | case RENEWING:
|
---|
| 789 | case REBINDING:
|
---|
| 790 | state = RENEW_REQUESTED;
|
---|
| 791 | break;
|
---|
| 792 | case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
|
---|
| 793 | udhcp_run_script(NULL, "deconfig");
|
---|
| 794 | case REQUESTING:
|
---|
| 795 | case RELEASED:
|
---|
| 796 | change_listen_mode(LISTEN_RAW);
|
---|
| 797 | state = INIT_SELECTING;
|
---|
| 798 | break;
|
---|
| 799 | case INIT_SELECTING:
|
---|
| 800 | break;
|
---|
| 801 | }
|
---|
| 802 | }
|
---|
| 803 |
|
---|
| 804 | static void perform_release(uint32_t requested_ip, uint32_t server_addr)
|
---|
| 805 | {
|
---|
| 806 | char buffer[sizeof("255.255.255.255")];
|
---|
| 807 | struct in_addr temp_addr;
|
---|
| 808 |
|
---|
| 809 | /* send release packet */
|
---|
| 810 | if (state == BOUND || state == RENEWING || state == REBINDING) {
|
---|
| 811 | temp_addr.s_addr = server_addr;
|
---|
| 812 | strcpy(buffer, inet_ntoa(temp_addr));
|
---|
| 813 | temp_addr.s_addr = requested_ip;
|
---|
| 814 | bb_info_msg("Unicasting a release of %s to %s",
|
---|
| 815 | inet_ntoa(temp_addr), buffer);
|
---|
| 816 | send_release(server_addr, requested_ip); /* unicast */
|
---|
| 817 | udhcp_run_script(NULL, "deconfig");
|
---|
| 818 | }
|
---|
| 819 | bb_info_msg("Entering released state");
|
---|
| 820 |
|
---|
| 821 | change_listen_mode(LISTEN_NONE);
|
---|
| 822 | state = RELEASED;
|
---|
| 823 | }
|
---|
| 824 |
|
---|
| 825 | static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
|
---|
| 826 | {
|
---|
| 827 | uint8_t *storage;
|
---|
| 828 | int len = strnlen(str, 255);
|
---|
| 829 | storage = xzalloc(len + extra + OPT_DATA);
|
---|
| 830 | storage[OPT_CODE] = code;
|
---|
| 831 | storage[OPT_LEN] = len + extra;
|
---|
| 832 | memcpy(storage + extra + OPT_DATA, str, len);
|
---|
| 833 | return storage;
|
---|
| 834 | }
|
---|
| 835 |
|
---|
| 836 | #if BB_MMU
|
---|
| 837 | static void client_background(void)
|
---|
| 838 | {
|
---|
| 839 | bb_daemonize(0);
|
---|
| 840 | logmode &= ~LOGMODE_STDIO;
|
---|
| 841 | /* rewrite pidfile, as our pid is different now */
|
---|
| 842 | write_pidfile(client_config.pidfile);
|
---|
| 843 | }
|
---|
| 844 | #endif
|
---|
| 845 |
|
---|
| 846 | //usage:#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
|
---|
| 847 | //usage:# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
|
---|
| 848 | //usage:#else
|
---|
| 849 | //usage:# define IF_UDHCP_VERBOSE(...)
|
---|
| 850 | //usage:#endif
|
---|
| 851 | //usage:#define udhcpc_trivial_usage
|
---|
| 852 | //usage: "[-fbnq"IF_UDHCP_VERBOSE("v")"oCR] [-i IFACE] [-r IP] [-s PROG] [-p PIDFILE]\n"
|
---|
| 853 | //usage: " [-H HOSTNAME] [-V VENDOR] [-x OPT:VAL]... [-O OPT]..." IF_FEATURE_UDHCP_PORT(" [-P N]")
|
---|
| 854 | //usage:#define udhcpc_full_usage "\n"
|
---|
| 855 | //usage: IF_LONG_OPTS(
|
---|
| 856 | //usage: "\n -i,--interface IFACE Interface to use (default eth0)"
|
---|
| 857 | //usage: "\n -p,--pidfile FILE Create pidfile"
|
---|
| 858 | //usage: "\n -s,--script PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
|
---|
| 859 | //usage: "\n -t,--retries N Send up to N discover packets"
|
---|
| 860 | //usage: "\n -T,--timeout N Pause between packets (default 3 seconds)"
|
---|
| 861 | //usage: "\n -A,--tryagain N Wait N seconds after failure (default 20)"
|
---|
| 862 | //usage: "\n -f,--foreground Run in foreground"
|
---|
| 863 | //usage: USE_FOR_MMU(
|
---|
| 864 | //usage: "\n -b,--background Background if lease is not obtained"
|
---|
| 865 | //usage: )
|
---|
| 866 | //usage: "\n -n,--now Exit if lease is not obtained"
|
---|
| 867 | //usage: "\n -q,--quit Exit after obtaining lease"
|
---|
| 868 | //usage: "\n -R,--release Release IP on exit"
|
---|
| 869 | //usage: "\n -S,--syslog Log to syslog too"
|
---|
| 870 | //usage: IF_FEATURE_UDHCP_PORT(
|
---|
| 871 | //usage: "\n -P,--client-port N Use port N (default 68)"
|
---|
| 872 | //usage: )
|
---|
| 873 | //usage: IF_FEATURE_UDHCPC_ARPING(
|
---|
| 874 | //usage: "\n -a,--arping Use arping to validate offered address"
|
---|
| 875 | //usage: )
|
---|
| 876 | //usage: "\n -O,--request-option OPT Request option OPT from server (cumulative)"
|
---|
| 877 | //usage: "\n -o,--no-default-options Don't request any options (unless -O is given)"
|
---|
| 878 | //usage: "\n -r,--request IP Request this IP address"
|
---|
| 879 | //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
|
---|
| 880 | //usage: "\n Examples of string, numeric, and hex byte opts:"
|
---|
| 881 | //usage: "\n -x hostname:bbox - option 12"
|
---|
| 882 | //usage: "\n -x lease:3600 - option 51 (lease time)"
|
---|
| 883 | //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
|
---|
| 884 | //usage: "\n -F,--fqdn NAME Ask server to update DNS mapping for NAME"
|
---|
| 885 | //usage: "\n -H,-h,--hostname NAME Send NAME as client hostname (default none)"
|
---|
| 886 | //usage: "\n -V,--vendorclass VENDOR Vendor identifier (default 'udhcp VERSION')"
|
---|
| 887 | //usage: "\n -C,--clientid-none Don't send MAC as client identifier"
|
---|
| 888 | //usage: IF_UDHCP_VERBOSE(
|
---|
| 889 | //usage: "\n -v Verbose"
|
---|
| 890 | //usage: )
|
---|
| 891 | //usage: )
|
---|
| 892 | //usage: IF_NOT_LONG_OPTS(
|
---|
| 893 | //usage: "\n -i IFACE Interface to use (default eth0)"
|
---|
| 894 | //usage: "\n -p FILE Create pidfile"
|
---|
| 895 | //usage: "\n -s PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
|
---|
| 896 | //usage: "\n -t N Send up to N discover packets"
|
---|
| 897 | //usage: "\n -T N Pause between packets (default 3 seconds)"
|
---|
| 898 | //usage: "\n -A N Wait N seconds (default 20) after failure"
|
---|
| 899 | //usage: "\n -f Run in foreground"
|
---|
| 900 | //usage: USE_FOR_MMU(
|
---|
| 901 | //usage: "\n -b Background if lease is not obtained"
|
---|
| 902 | //usage: )
|
---|
| 903 | //usage: "\n -n Exit if lease is not obtained"
|
---|
| 904 | //usage: "\n -q Exit after obtaining lease"
|
---|
| 905 | //usage: "\n -R Release IP on exit"
|
---|
| 906 | //usage: "\n -S Log to syslog too"
|
---|
| 907 | //usage: IF_FEATURE_UDHCP_PORT(
|
---|
| 908 | //usage: "\n -P N Use port N (default 68)"
|
---|
| 909 | //usage: )
|
---|
| 910 | //usage: IF_FEATURE_UDHCPC_ARPING(
|
---|
| 911 | //usage: "\n -a Use arping to validate offered address"
|
---|
| 912 | //usage: )
|
---|
| 913 | //usage: "\n -O OPT Request option OPT from server (cumulative)"
|
---|
| 914 | //usage: "\n -o Don't request any options (unless -O is given)"
|
---|
| 915 | //usage: "\n -r IP Request this IP address"
|
---|
| 916 | //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
|
---|
| 917 | //usage: "\n Examples of string, numeric, and hex byte opts:"
|
---|
| 918 | //usage: "\n -x hostname:bbox - option 12"
|
---|
| 919 | //usage: "\n -x lease:3600 - option 51 (lease time)"
|
---|
| 920 | //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
|
---|
| 921 | //usage: "\n -F NAME Ask server to update DNS mapping for NAME"
|
---|
| 922 | //usage: "\n -H,-h NAME Send NAME as client hostname (default none)"
|
---|
| 923 | //usage: "\n -V VENDOR Vendor identifier (default 'udhcp VERSION')"
|
---|
| 924 | //usage: "\n -C Don't send MAC as client identifier"
|
---|
| 925 | //usage: IF_UDHCP_VERBOSE(
|
---|
| 926 | //usage: "\n -v Verbose"
|
---|
| 927 | //usage: )
|
---|
| 928 | //usage: )
|
---|
| 929 |
|
---|
| 930 | int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
---|
| 931 | int udhcpc_main(int argc UNUSED_PARAM, char **argv)
|
---|
| 932 | {
|
---|
| 933 | uint8_t *temp, *message;
|
---|
| 934 | const char *str_V, *str_h, *str_F, *str_r;
|
---|
| 935 | IF_FEATURE_UDHCP_PORT(char *str_P;)
|
---|
| 936 | void *clientid_mac_ptr;
|
---|
| 937 | llist_t *list_O = NULL;
|
---|
| 938 | llist_t *list_x = NULL;
|
---|
| 939 | int tryagain_timeout = 20;
|
---|
| 940 | int discover_timeout = 3;
|
---|
| 941 | int discover_retries = 3;
|
---|
| 942 | uint32_t server_addr = server_addr; /* for compiler */
|
---|
| 943 | uint32_t requested_ip = 0;
|
---|
| 944 | uint32_t xid = 0;
|
---|
| 945 | uint32_t lease_seconds = 0; /* can be given as 32-bit quantity */
|
---|
| 946 | int packet_num;
|
---|
| 947 | int timeout; /* must be signed */
|
---|
| 948 | unsigned already_waited_sec;
|
---|
| 949 | unsigned opt;
|
---|
| 950 | int max_fd;
|
---|
| 951 | int retval;
|
---|
| 952 | struct timeval tv;
|
---|
| 953 | struct dhcp_packet packet;
|
---|
| 954 | fd_set rfds;
|
---|
| 955 |
|
---|
| 956 | #if ENABLE_LONG_OPTS
|
---|
| 957 | static const char udhcpc_longopts[] ALIGN1 =
|
---|
| 958 | "clientid-none\0" No_argument "C"
|
---|
| 959 | "vendorclass\0" Required_argument "V"
|
---|
| 960 | "hostname\0" Required_argument "H"
|
---|
| 961 | "fqdn\0" Required_argument "F"
|
---|
| 962 | "interface\0" Required_argument "i"
|
---|
| 963 | "now\0" No_argument "n"
|
---|
| 964 | "pidfile\0" Required_argument "p"
|
---|
| 965 | "quit\0" No_argument "q"
|
---|
| 966 | "release\0" No_argument "R"
|
---|
| 967 | "request\0" Required_argument "r"
|
---|
| 968 | "script\0" Required_argument "s"
|
---|
| 969 | "timeout\0" Required_argument "T"
|
---|
| 970 | "version\0" No_argument "v"
|
---|
| 971 | "retries\0" Required_argument "t"
|
---|
| 972 | "tryagain\0" Required_argument "A"
|
---|
| 973 | "syslog\0" No_argument "S"
|
---|
| 974 | "request-option\0" Required_argument "O"
|
---|
| 975 | "no-default-options\0" No_argument "o"
|
---|
| 976 | "foreground\0" No_argument "f"
|
---|
| 977 | "background\0" No_argument "b"
|
---|
| 978 | IF_FEATURE_UDHCPC_ARPING("arping\0" No_argument "a")
|
---|
| 979 | IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
|
---|
| 980 | ;
|
---|
| 981 | #endif
|
---|
| 982 | enum {
|
---|
| 983 | OPT_C = 1 << 0,
|
---|
| 984 | OPT_V = 1 << 1,
|
---|
| 985 | OPT_H = 1 << 2,
|
---|
| 986 | OPT_h = 1 << 3,
|
---|
| 987 | OPT_F = 1 << 4,
|
---|
| 988 | OPT_i = 1 << 5,
|
---|
| 989 | OPT_n = 1 << 6,
|
---|
| 990 | OPT_p = 1 << 7,
|
---|
| 991 | OPT_q = 1 << 8,
|
---|
| 992 | OPT_R = 1 << 9,
|
---|
| 993 | OPT_r = 1 << 10,
|
---|
| 994 | OPT_s = 1 << 11,
|
---|
| 995 | OPT_T = 1 << 12,
|
---|
| 996 | OPT_t = 1 << 13,
|
---|
| 997 | OPT_S = 1 << 14,
|
---|
| 998 | OPT_A = 1 << 15,
|
---|
| 999 | OPT_O = 1 << 16,
|
---|
| 1000 | OPT_o = 1 << 17,
|
---|
| 1001 | OPT_x = 1 << 18,
|
---|
| 1002 | OPT_f = 1 << 19,
|
---|
| 1003 | /* The rest has variable bit positions, need to be clever */
|
---|
| 1004 | OPTBIT_f = 19,
|
---|
| 1005 | USE_FOR_MMU( OPTBIT_b,)
|
---|
| 1006 | IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
|
---|
| 1007 | IF_FEATURE_UDHCP_PORT( OPTBIT_P,)
|
---|
| 1008 | USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
|
---|
| 1009 | IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
|
---|
| 1010 | IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
|
---|
| 1011 | };
|
---|
| 1012 |
|
---|
| 1013 | /* Default options */
|
---|
| 1014 | IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
|
---|
| 1015 | IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
|
---|
| 1016 | client_config.interface = "eth0";
|
---|
| 1017 | client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
|
---|
| 1018 | str_V = "udhcp "BB_VER;
|
---|
| 1019 |
|
---|
| 1020 | /* Parse command line */
|
---|
| 1021 | /* O,x: list; -T,-t,-A take numeric param */
|
---|
| 1022 | opt_complementary = "O::x::T+:t+:A+"
|
---|
| 1023 | #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
|
---|
| 1024 | ":vv"
|
---|
| 1025 | #endif
|
---|
| 1026 | ;
|
---|
| 1027 | IF_LONG_OPTS(applet_long_options = udhcpc_longopts;)
|
---|
| 1028 | opt = getopt32(argv, "CV:H:h:F:i:np:qRr:s:T:t:SA:O:ox:f"
|
---|
| 1029 | USE_FOR_MMU("b")
|
---|
| 1030 | IF_FEATURE_UDHCPC_ARPING("a")
|
---|
| 1031 | IF_FEATURE_UDHCP_PORT("P:")
|
---|
| 1032 | "v"
|
---|
| 1033 | , &str_V, &str_h, &str_h, &str_F
|
---|
| 1034 | , &client_config.interface, &client_config.pidfile, &str_r /* i,p */
|
---|
| 1035 | , &client_config.script /* s */
|
---|
| 1036 | , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
|
---|
| 1037 | , &list_O
|
---|
| 1038 | , &list_x
|
---|
| 1039 | IF_FEATURE_UDHCP_PORT(, &str_P)
|
---|
| 1040 | #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
|
---|
| 1041 | , &dhcp_verbose
|
---|
| 1042 | #endif
|
---|
| 1043 | );
|
---|
| 1044 | if (opt & (OPT_h|OPT_H))
|
---|
| 1045 | client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
|
---|
| 1046 | if (opt & OPT_F) {
|
---|
| 1047 | /* FQDN option format: [0x51][len][flags][0][0]<fqdn> */
|
---|
| 1048 | client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
|
---|
| 1049 | /* Flag bits: 0000NEOS
|
---|
| 1050 | * S: 1 = Client requests server to update A RR in DNS as well as PTR
|
---|
| 1051 | * O: 1 = Server indicates to client that DNS has been updated regardless
|
---|
| 1052 | * E: 1 = Name is in DNS format, i.e. <4>host<6>domain<3>com<0>,
|
---|
| 1053 | * not "host.domain.com". Format 0 is obsolete.
|
---|
| 1054 | * N: 1 = Client requests server to not update DNS (S must be 0 then)
|
---|
| 1055 | * Two [0] bytes which follow are deprecated and must be 0.
|
---|
| 1056 | */
|
---|
| 1057 | client_config.fqdn[OPT_DATA + 0] = 0x1;
|
---|
| 1058 | /*client_config.fqdn[OPT_DATA + 1] = 0; - xzalloc did it */
|
---|
| 1059 | /*client_config.fqdn[OPT_DATA + 2] = 0; */
|
---|
| 1060 | }
|
---|
| 1061 | if (opt & OPT_r)
|
---|
| 1062 | requested_ip = inet_addr(str_r);
|
---|
| 1063 | #if ENABLE_FEATURE_UDHCP_PORT
|
---|
| 1064 | if (opt & OPT_P) {
|
---|
| 1065 | CLIENT_PORT = xatou16(str_P);
|
---|
| 1066 | SERVER_PORT = CLIENT_PORT - 1;
|
---|
| 1067 | }
|
---|
| 1068 | #endif
|
---|
| 1069 | if (opt & OPT_o)
|
---|
| 1070 | client_config.no_default_options = 1;
|
---|
| 1071 | while (list_O) {
|
---|
| 1072 | char *optstr = llist_pop(&list_O);
|
---|
| 1073 | unsigned n = udhcp_option_idx(optstr);
|
---|
| 1074 | n = dhcp_optflags[n].code;
|
---|
| 1075 | client_config.opt_mask[n >> 3] |= 1 << (n & 7);
|
---|
| 1076 | }
|
---|
| 1077 | while (list_x) {
|
---|
| 1078 | char *optstr = llist_pop(&list_x);
|
---|
| 1079 | char *colon = strchr(optstr, ':');
|
---|
| 1080 | if (colon)
|
---|
| 1081 | *colon = ' ';
|
---|
| 1082 | /* now it looks similar to udhcpd's config file line:
|
---|
| 1083 | * "optname optval", using the common routine: */
|
---|
| 1084 | udhcp_str2optset(optstr, &client_config.options);
|
---|
| 1085 | }
|
---|
| 1086 |
|
---|
| 1087 | if (udhcp_read_interface(client_config.interface,
|
---|
| 1088 | &client_config.ifindex,
|
---|
| 1089 | NULL,
|
---|
| 1090 | client_config.client_mac)
|
---|
| 1091 | ) {
|
---|
| 1092 | return 1;
|
---|
| 1093 | }
|
---|
| 1094 |
|
---|
| 1095 | clientid_mac_ptr = NULL;
|
---|
| 1096 | if (!(opt & OPT_C) && !udhcp_find_option(client_config.options, DHCP_CLIENT_ID)) {
|
---|
| 1097 | /* not suppressed and not set, set the default client ID */
|
---|
| 1098 | client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
|
---|
| 1099 | client_config.clientid[OPT_DATA] = 1; /* type: ethernet */
|
---|
| 1100 | clientid_mac_ptr = client_config.clientid + OPT_DATA+1;
|
---|
| 1101 | memcpy(clientid_mac_ptr, client_config.client_mac, 6);
|
---|
| 1102 | }
|
---|
| 1103 | if (str_V[0] != '\0')
|
---|
| 1104 | client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
|
---|
| 1105 | #if !BB_MMU
|
---|
| 1106 | /* on NOMMU reexec (i.e., background) early */
|
---|
| 1107 | if (!(opt & OPT_f)) {
|
---|
| 1108 | bb_daemonize_or_rexec(0 /* flags */, argv);
|
---|
| 1109 | logmode = LOGMODE_NONE;
|
---|
| 1110 | }
|
---|
| 1111 | #endif
|
---|
| 1112 | if (opt & OPT_S) {
|
---|
| 1113 | openlog(applet_name, LOG_PID, LOG_DAEMON);
|
---|
| 1114 | logmode |= LOGMODE_SYSLOG;
|
---|
| 1115 | }
|
---|
| 1116 |
|
---|
| 1117 | /* Make sure fd 0,1,2 are open */
|
---|
| 1118 | bb_sanitize_stdio();
|
---|
| 1119 | /* Equivalent of doing a fflush after every \n */
|
---|
| 1120 | setlinebuf(stdout);
|
---|
| 1121 | /* Create pidfile */
|
---|
| 1122 | write_pidfile(client_config.pidfile);
|
---|
| 1123 | /* Goes to stdout (unless NOMMU) and possibly syslog */
|
---|
| 1124 | bb_info_msg("%s (v"BB_VER") started", applet_name);
|
---|
| 1125 | /* Set up the signal pipe */
|
---|
| 1126 | udhcp_sp_setup();
|
---|
| 1127 | /* We want random_xid to be random... */
|
---|
| 1128 | srand(monotonic_us());
|
---|
| 1129 |
|
---|
| 1130 | state = INIT_SELECTING;
|
---|
| 1131 | udhcp_run_script(NULL, "deconfig");
|
---|
| 1132 | change_listen_mode(LISTEN_RAW);
|
---|
| 1133 | packet_num = 0;
|
---|
| 1134 | timeout = 0;
|
---|
| 1135 | already_waited_sec = 0;
|
---|
| 1136 |
|
---|
| 1137 | /* Main event loop. select() waits on signal pipe and possibly
|
---|
| 1138 | * on sockfd.
|
---|
| 1139 | * "continue" statements in code below jump to the top of the loop.
|
---|
| 1140 | */
|
---|
| 1141 | for (;;) {
|
---|
| 1142 | /* silence "uninitialized!" warning */
|
---|
| 1143 | unsigned timestamp_before_wait = timestamp_before_wait;
|
---|
| 1144 |
|
---|
| 1145 | //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
|
---|
| 1146 |
|
---|
| 1147 | /* Was opening raw or udp socket here
|
---|
| 1148 | * if (listen_mode != LISTEN_NONE && sockfd < 0),
|
---|
| 1149 | * but on fast network renew responses return faster
|
---|
| 1150 | * than we open sockets. Thus this code is moved
|
---|
| 1151 | * to change_listen_mode(). Thus we open listen socket
|
---|
| 1152 | * BEFORE we send renew request (see "case BOUND:"). */
|
---|
| 1153 |
|
---|
| 1154 | max_fd = udhcp_sp_fd_set(&rfds, sockfd);
|
---|
| 1155 |
|
---|
| 1156 | tv.tv_sec = timeout - already_waited_sec;
|
---|
| 1157 | tv.tv_usec = 0;
|
---|
| 1158 | retval = 0;
|
---|
| 1159 | /* If we already timed out, fall through with retval = 0, else... */
|
---|
| 1160 | if ((int)tv.tv_sec > 0) {
|
---|
| 1161 | timestamp_before_wait = (unsigned)monotonic_sec();
|
---|
| 1162 | log1("Waiting on select...");
|
---|
| 1163 | retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
|
---|
| 1164 | if (retval < 0) {
|
---|
| 1165 | /* EINTR? A signal was caught, don't panic */
|
---|
| 1166 | if (errno == EINTR) {
|
---|
| 1167 | already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
|
---|
| 1168 | continue;
|
---|
| 1169 | }
|
---|
| 1170 | /* Else: an error occured, panic! */
|
---|
| 1171 | bb_perror_msg_and_die("select");
|
---|
| 1172 | }
|
---|
| 1173 | }
|
---|
| 1174 |
|
---|
| 1175 | /* If timeout dropped to zero, time to become active:
|
---|
| 1176 | * resend discover/renew/whatever
|
---|
| 1177 | */
|
---|
| 1178 | if (retval == 0) {
|
---|
| 1179 | /* When running on a bridge, the ifindex may have changed
|
---|
| 1180 | * (e.g. if member interfaces were added/removed
|
---|
| 1181 | * or if the status of the bridge changed).
|
---|
| 1182 | * Refresh ifindex and client_mac:
|
---|
| 1183 | */
|
---|
| 1184 | if (udhcp_read_interface(client_config.interface,
|
---|
| 1185 | &client_config.ifindex,
|
---|
| 1186 | NULL,
|
---|
| 1187 | client_config.client_mac)
|
---|
| 1188 | ) {
|
---|
| 1189 | return 1; /* iface is gone? */
|
---|
| 1190 | }
|
---|
| 1191 | if (clientid_mac_ptr)
|
---|
| 1192 | memcpy(clientid_mac_ptr, client_config.client_mac, 6);
|
---|
| 1193 |
|
---|
| 1194 | /* We will restart the wait in any case */
|
---|
| 1195 | already_waited_sec = 0;
|
---|
| 1196 |
|
---|
| 1197 | switch (state) {
|
---|
| 1198 | case INIT_SELECTING:
|
---|
| 1199 | if (packet_num < discover_retries) {
|
---|
| 1200 | if (packet_num == 0)
|
---|
| 1201 | xid = random_xid();
|
---|
| 1202 | /* broadcast */
|
---|
| 1203 | send_discover(xid, requested_ip);
|
---|
| 1204 | timeout = discover_timeout;
|
---|
| 1205 | packet_num++;
|
---|
| 1206 | continue;
|
---|
| 1207 | }
|
---|
| 1208 | leasefail:
|
---|
| 1209 | udhcp_run_script(NULL, "leasefail");
|
---|
| 1210 | #if BB_MMU /* -b is not supported on NOMMU */
|
---|
| 1211 | if (opt & OPT_b) { /* background if no lease */
|
---|
| 1212 | bb_info_msg("No lease, forking to background");
|
---|
| 1213 | client_background();
|
---|
| 1214 | /* do not background again! */
|
---|
| 1215 | opt = ((opt & ~OPT_b) | OPT_f);
|
---|
| 1216 | } else
|
---|
| 1217 | #endif
|
---|
| 1218 | if (opt & OPT_n) { /* abort if no lease */
|
---|
| 1219 | bb_info_msg("No lease, failing");
|
---|
| 1220 | retval = 1;
|
---|
| 1221 | goto ret;
|
---|
| 1222 | }
|
---|
| 1223 | /* wait before trying again */
|
---|
| 1224 | timeout = tryagain_timeout;
|
---|
| 1225 | packet_num = 0;
|
---|
| 1226 | continue;
|
---|
| 1227 | case REQUESTING:
|
---|
| 1228 | if (packet_num < discover_retries) {
|
---|
| 1229 | /* send broadcast select packet */
|
---|
| 1230 | send_select(xid, server_addr, requested_ip);
|
---|
| 1231 | timeout = discover_timeout;
|
---|
| 1232 | packet_num++;
|
---|
| 1233 | continue;
|
---|
| 1234 | }
|
---|
| 1235 | /* Timed out, go back to init state.
|
---|
| 1236 | * "discover...select...discover..." loops
|
---|
| 1237 | * were seen in the wild. Treat them similarly
|
---|
| 1238 | * to "no response to discover" case */
|
---|
| 1239 | change_listen_mode(LISTEN_RAW);
|
---|
| 1240 | state = INIT_SELECTING;
|
---|
| 1241 | goto leasefail;
|
---|
| 1242 | case BOUND:
|
---|
| 1243 | /* 1/2 lease passed, enter renewing state */
|
---|
| 1244 | state = RENEWING;
|
---|
| 1245 | change_listen_mode(LISTEN_KERNEL);
|
---|
| 1246 | log1("Entering renew state");
|
---|
| 1247 | /* fall right through */
|
---|
| 1248 | case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
|
---|
| 1249 | case_RENEW_REQUESTED:
|
---|
| 1250 | case RENEWING:
|
---|
| 1251 | if (timeout > 60) {
|
---|
| 1252 | /* send an unicast renew request */
|
---|
| 1253 | /* Sometimes observed to fail (EADDRNOTAVAIL) to bind
|
---|
| 1254 | * a new UDP socket for sending inside send_renew.
|
---|
| 1255 | * I hazard to guess existing listening socket
|
---|
| 1256 | * is somehow conflicting with it, but why is it
|
---|
| 1257 | * not deterministic then?! Strange.
|
---|
| 1258 | * Anyway, it does recover by eventually failing through
|
---|
| 1259 | * into INIT_SELECTING state.
|
---|
| 1260 | */
|
---|
| 1261 | send_renew(xid, server_addr, requested_ip);
|
---|
| 1262 | timeout >>= 1;
|
---|
| 1263 | continue;
|
---|
| 1264 | }
|
---|
| 1265 | /* Timed out, enter rebinding state */
|
---|
| 1266 | log1("Entering rebinding state");
|
---|
| 1267 | state = REBINDING;
|
---|
| 1268 | /* fall right through */
|
---|
| 1269 | case REBINDING:
|
---|
| 1270 | /* Switch to bcast receive */
|
---|
| 1271 | change_listen_mode(LISTEN_RAW);
|
---|
| 1272 | /* Lease is *really* about to run out,
|
---|
| 1273 | * try to find DHCP server using broadcast */
|
---|
| 1274 | if (timeout > 0) {
|
---|
| 1275 | /* send a broadcast renew request */
|
---|
| 1276 | send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
|
---|
| 1277 | timeout >>= 1;
|
---|
| 1278 | continue;
|
---|
| 1279 | }
|
---|
| 1280 | /* Timed out, enter init state */
|
---|
| 1281 | bb_info_msg("Lease lost, entering init state");
|
---|
| 1282 | udhcp_run_script(NULL, "deconfig");
|
---|
| 1283 | state = INIT_SELECTING;
|
---|
| 1284 | /*timeout = 0; - already is */
|
---|
| 1285 | packet_num = 0;
|
---|
| 1286 | continue;
|
---|
| 1287 | /* case RELEASED: */
|
---|
| 1288 | }
|
---|
| 1289 | /* yah, I know, *you* say it would never happen */
|
---|
| 1290 | timeout = INT_MAX;
|
---|
| 1291 | continue; /* back to main loop */
|
---|
| 1292 | } /* if select timed out */
|
---|
| 1293 |
|
---|
| 1294 | /* select() didn't timeout, something happened */
|
---|
| 1295 |
|
---|
| 1296 | /* Is it a signal? */
|
---|
| 1297 | /* note: udhcp_sp_read checks FD_ISSET before reading */
|
---|
| 1298 | switch (udhcp_sp_read(&rfds)) {
|
---|
| 1299 | case SIGUSR1:
|
---|
| 1300 | perform_renew();
|
---|
| 1301 | if (state == RENEW_REQUESTED)
|
---|
| 1302 | goto case_RENEW_REQUESTED;
|
---|
| 1303 | /* Start things over */
|
---|
| 1304 | packet_num = 0;
|
---|
| 1305 | /* Kill any timeouts, user wants this to hurry along */
|
---|
| 1306 | timeout = 0;
|
---|
| 1307 | continue;
|
---|
| 1308 | case SIGUSR2:
|
---|
| 1309 | perform_release(requested_ip, server_addr);
|
---|
| 1310 | timeout = INT_MAX;
|
---|
| 1311 | continue;
|
---|
| 1312 | case SIGTERM:
|
---|
| 1313 | bb_info_msg("Received SIGTERM");
|
---|
| 1314 | if (opt & OPT_R) /* release on quit */
|
---|
| 1315 | perform_release(requested_ip, server_addr);
|
---|
| 1316 | goto ret0;
|
---|
| 1317 | }
|
---|
| 1318 |
|
---|
| 1319 | /* Is it a packet? */
|
---|
| 1320 | if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds))
|
---|
| 1321 | continue; /* no */
|
---|
| 1322 |
|
---|
| 1323 | {
|
---|
| 1324 | int len;
|
---|
| 1325 |
|
---|
| 1326 | /* A packet is ready, read it */
|
---|
| 1327 | if (listen_mode == LISTEN_KERNEL)
|
---|
| 1328 | len = udhcp_recv_kernel_packet(&packet, sockfd);
|
---|
| 1329 | else
|
---|
| 1330 | len = udhcp_recv_raw_packet(&packet, sockfd);
|
---|
| 1331 | if (len == -1) {
|
---|
| 1332 | /* Error is severe, reopen socket */
|
---|
| 1333 | bb_info_msg("Read error: %s, reopening socket", strerror(errno));
|
---|
| 1334 | sleep(discover_timeout); /* 3 seconds by default */
|
---|
| 1335 | change_listen_mode(listen_mode); /* just close and reopen */
|
---|
| 1336 | }
|
---|
| 1337 | /* If this packet will turn out to be unrelated/bogus,
|
---|
| 1338 | * we will go back and wait for next one.
|
---|
| 1339 | * Be sure timeout is properly decreased. */
|
---|
| 1340 | already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
|
---|
| 1341 | if (len < 0)
|
---|
| 1342 | continue;
|
---|
| 1343 | }
|
---|
| 1344 |
|
---|
| 1345 | if (packet.xid != xid) {
|
---|
| 1346 | log1("xid %x (our is %x), ignoring packet",
|
---|
| 1347 | (unsigned)packet.xid, (unsigned)xid);
|
---|
| 1348 | continue;
|
---|
| 1349 | }
|
---|
| 1350 |
|
---|
| 1351 | /* Ignore packets that aren't for us */
|
---|
| 1352 | if (packet.hlen != 6
|
---|
| 1353 | || memcmp(packet.chaddr, client_config.client_mac, 6) != 0
|
---|
| 1354 | ) {
|
---|
| 1355 | //FIXME: need to also check that last 10 bytes are zero
|
---|
| 1356 | log1("chaddr does not match, ignoring packet"); // log2?
|
---|
| 1357 | continue;
|
---|
| 1358 | }
|
---|
| 1359 |
|
---|
| 1360 | message = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE);
|
---|
| 1361 | if (message == NULL) {
|
---|
| 1362 | bb_error_msg("no message type option, ignoring packet");
|
---|
| 1363 | continue;
|
---|
| 1364 | }
|
---|
| 1365 |
|
---|
| 1366 | switch (state) {
|
---|
| 1367 | case INIT_SELECTING:
|
---|
| 1368 | /* Must be a DHCPOFFER to one of our xid's */
|
---|
| 1369 | if (*message == DHCPOFFER) {
|
---|
| 1370 | /* TODO: why we don't just fetch server's IP from IP header? */
|
---|
| 1371 | temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
|
---|
| 1372 | if (!temp) {
|
---|
| 1373 | bb_error_msg("no server ID, ignoring packet");
|
---|
| 1374 | continue;
|
---|
| 1375 | /* still selecting - this server looks bad */
|
---|
| 1376 | }
|
---|
| 1377 | /* it IS unaligned sometimes, don't "optimize" */
|
---|
| 1378 | move_from_unaligned32(server_addr, temp);
|
---|
| 1379 | /*xid = packet.xid; - already is */
|
---|
| 1380 | requested_ip = packet.yiaddr;
|
---|
| 1381 |
|
---|
| 1382 | /* enter requesting state */
|
---|
| 1383 | state = REQUESTING;
|
---|
| 1384 | timeout = 0;
|
---|
| 1385 | packet_num = 0;
|
---|
| 1386 | already_waited_sec = 0;
|
---|
| 1387 | }
|
---|
| 1388 | continue;
|
---|
| 1389 | case REQUESTING:
|
---|
| 1390 | case RENEWING:
|
---|
| 1391 | case RENEW_REQUESTED:
|
---|
| 1392 | case REBINDING:
|
---|
| 1393 | if (*message == DHCPACK) {
|
---|
| 1394 | temp = udhcp_get_option(&packet, DHCP_LEASE_TIME);
|
---|
| 1395 | if (!temp) {
|
---|
| 1396 | bb_error_msg("no lease time with ACK, using 1 hour lease");
|
---|
| 1397 | lease_seconds = 60 * 60;
|
---|
| 1398 | } else {
|
---|
| 1399 | /* it IS unaligned sometimes, don't "optimize" */
|
---|
| 1400 | move_from_unaligned32(lease_seconds, temp);
|
---|
| 1401 | lease_seconds = ntohl(lease_seconds);
|
---|
| 1402 | lease_seconds &= 0x0fffffff; /* paranoia: must not be prone to overflows */
|
---|
| 1403 | if (lease_seconds < 10) /* and not too small */
|
---|
| 1404 | lease_seconds = 10;
|
---|
| 1405 | }
|
---|
| 1406 | #if ENABLE_FEATURE_UDHCPC_ARPING
|
---|
| 1407 | if (opt & OPT_a) {
|
---|
| 1408 | /* RFC 2131 3.1 paragraph 5:
|
---|
| 1409 | * "The client receives the DHCPACK message with configuration
|
---|
| 1410 | * parameters. The client SHOULD perform a final check on the
|
---|
| 1411 | * parameters (e.g., ARP for allocated network address), and notes
|
---|
| 1412 | * the duration of the lease specified in the DHCPACK message. At this
|
---|
| 1413 | * point, the client is configured. If the client detects that the
|
---|
| 1414 | * address is already in use (e.g., through the use of ARP),
|
---|
| 1415 | * the client MUST send a DHCPDECLINE message to the server and restarts
|
---|
| 1416 | * the configuration process..." */
|
---|
| 1417 | if (!arpping(packet.yiaddr,
|
---|
| 1418 | NULL,
|
---|
| 1419 | (uint32_t) 0,
|
---|
| 1420 | client_config.client_mac,
|
---|
| 1421 | client_config.interface)
|
---|
| 1422 | ) {
|
---|
| 1423 | bb_info_msg("Offered address is in use "
|
---|
| 1424 | "(got ARP reply), declining");
|
---|
| 1425 | send_decline(xid, server_addr, packet.yiaddr);
|
---|
| 1426 |
|
---|
| 1427 | if (state != REQUESTING)
|
---|
| 1428 | udhcp_run_script(NULL, "deconfig");
|
---|
| 1429 | change_listen_mode(LISTEN_RAW);
|
---|
| 1430 | state = INIT_SELECTING;
|
---|
| 1431 | requested_ip = 0;
|
---|
| 1432 | timeout = tryagain_timeout;
|
---|
| 1433 | packet_num = 0;
|
---|
| 1434 | already_waited_sec = 0;
|
---|
| 1435 | continue; /* back to main loop */
|
---|
| 1436 | }
|
---|
| 1437 | }
|
---|
| 1438 | #endif
|
---|
| 1439 | /* enter bound state */
|
---|
| 1440 | timeout = lease_seconds / 2;
|
---|
| 1441 | {
|
---|
| 1442 | struct in_addr temp_addr;
|
---|
| 1443 | temp_addr.s_addr = packet.yiaddr;
|
---|
| 1444 | bb_info_msg("Lease of %s obtained, lease time %u",
|
---|
| 1445 | inet_ntoa(temp_addr), (unsigned)lease_seconds);
|
---|
| 1446 | }
|
---|
| 1447 | requested_ip = packet.yiaddr;
|
---|
| 1448 | udhcp_run_script(&packet, state == REQUESTING ? "bound" : "renew");
|
---|
| 1449 |
|
---|
| 1450 | state = BOUND;
|
---|
| 1451 | change_listen_mode(LISTEN_NONE);
|
---|
| 1452 | if (opt & OPT_q) { /* quit after lease */
|
---|
| 1453 | if (opt & OPT_R) /* release on quit */
|
---|
| 1454 | perform_release(requested_ip, server_addr);
|
---|
| 1455 | goto ret0;
|
---|
| 1456 | }
|
---|
| 1457 | /* future renew failures should not exit (JM) */
|
---|
| 1458 | opt &= ~OPT_n;
|
---|
| 1459 | #if BB_MMU /* NOMMU case backgrounded earlier */
|
---|
| 1460 | if (!(opt & OPT_f)) {
|
---|
| 1461 | client_background();
|
---|
| 1462 | /* do not background again! */
|
---|
| 1463 | opt = ((opt & ~OPT_b) | OPT_f);
|
---|
| 1464 | }
|
---|
| 1465 | #endif
|
---|
| 1466 | already_waited_sec = 0;
|
---|
| 1467 | continue; /* back to main loop */
|
---|
| 1468 | }
|
---|
| 1469 | if (*message == DHCPNAK) {
|
---|
| 1470 | /* return to init state */
|
---|
| 1471 | bb_info_msg("Received DHCP NAK");
|
---|
| 1472 | udhcp_run_script(&packet, "nak");
|
---|
| 1473 | if (state != REQUESTING)
|
---|
| 1474 | udhcp_run_script(NULL, "deconfig");
|
---|
| 1475 | change_listen_mode(LISTEN_RAW);
|
---|
| 1476 | sleep(3); /* avoid excessive network traffic */
|
---|
| 1477 | state = INIT_SELECTING;
|
---|
| 1478 | requested_ip = 0;
|
---|
| 1479 | timeout = 0;
|
---|
| 1480 | packet_num = 0;
|
---|
| 1481 | already_waited_sec = 0;
|
---|
| 1482 | }
|
---|
| 1483 | continue;
|
---|
| 1484 | /* case BOUND: - ignore all packets */
|
---|
| 1485 | /* case RELEASED: - ignore all packets */
|
---|
| 1486 | }
|
---|
| 1487 | /* back to main loop */
|
---|
| 1488 | } /* for (;;) - main loop ends */
|
---|
| 1489 |
|
---|
| 1490 | ret0:
|
---|
| 1491 | retval = 0;
|
---|
| 1492 | ret:
|
---|
| 1493 | /*if (client_config.pidfile) - remove_pidfile has its own check */
|
---|
| 1494 | remove_pidfile(client_config.pidfile);
|
---|
| 1495 | return retval;
|
---|
| 1496 | }
|
---|