[1765] | 1 | /* vi: set sw=4 ts=4: */
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[2725] | 2 | /*
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| 3 | * udhcp client
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[821] | 4 | *
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| 5 | * Russ Dill <Russ.Dill@asu.edu> July 2001
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| 6 | *
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[2725] | 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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[821] | 20 | */
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[1765] | 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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[821] | 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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[3621] | 28 | #include <netinet/if_ether.h>
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[2725] | 29 | #include <linux/filter.h>
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[3621] | 30 | #include <linux/if_packet.h>
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[1765] | 31 |
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[3621] | 32 | #ifndef PACKET_AUXDATA
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| 33 | # define PACKET_AUXDATA 8
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| 34 | struct tpacket_auxdata {
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| 35 | uint32_t tp_status;
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| 36 | uint32_t tp_len;
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| 37 | uint32_t tp_snaplen;
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| 38 | uint16_t tp_mac;
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| 39 | uint16_t tp_net;
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| 40 | uint16_t tp_vlan_tci;
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| 41 | uint16_t tp_padding;
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| 42 | };
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| 43 | #endif
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| 44 |
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| 45 |
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[3232] | 46 | /* "struct client_config_t client_config" is in bb_common_bufsiz1 */
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[2725] | 47 |
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| 48 |
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[3232] | 49 | #if ENABLE_LONG_OPTS
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| 50 | static const char udhcpc_longopts[] ALIGN1 =
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| 51 | "clientid-none\0" No_argument "C"
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| 52 | "vendorclass\0" Required_argument "V"
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| 53 | "hostname\0" Required_argument "H"
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| 54 | "fqdn\0" Required_argument "F"
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| 55 | "interface\0" Required_argument "i"
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| 56 | "now\0" No_argument "n"
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| 57 | "pidfile\0" Required_argument "p"
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| 58 | "quit\0" No_argument "q"
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| 59 | "release\0" No_argument "R"
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| 60 | "request\0" Required_argument "r"
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| 61 | "script\0" Required_argument "s"
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| 62 | "timeout\0" Required_argument "T"
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| 63 | "retries\0" Required_argument "t"
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| 64 | "tryagain\0" Required_argument "A"
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| 65 | "syslog\0" No_argument "S"
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| 66 | "request-option\0" Required_argument "O"
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| 67 | "no-default-options\0" No_argument "o"
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| 68 | "foreground\0" No_argument "f"
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| 69 | "background\0" No_argument "b"
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| 70 | "broadcast\0" No_argument "B"
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[3621] | 71 | IF_FEATURE_UDHCPC_ARPING("arping\0" Optional_argument "a")
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[3232] | 72 | IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
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| 73 | ;
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| 74 | #endif
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| 75 | /* Must match getopt32 option string order */
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| 76 | enum {
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| 77 | OPT_C = 1 << 0,
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| 78 | OPT_V = 1 << 1,
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| 79 | OPT_H = 1 << 2,
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| 80 | OPT_h = 1 << 3,
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| 81 | OPT_F = 1 << 4,
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| 82 | OPT_i = 1 << 5,
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| 83 | OPT_n = 1 << 6,
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| 84 | OPT_p = 1 << 7,
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| 85 | OPT_q = 1 << 8,
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| 86 | OPT_R = 1 << 9,
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| 87 | OPT_r = 1 << 10,
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| 88 | OPT_s = 1 << 11,
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| 89 | OPT_T = 1 << 12,
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| 90 | OPT_t = 1 << 13,
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| 91 | OPT_S = 1 << 14,
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| 92 | OPT_A = 1 << 15,
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| 93 | OPT_O = 1 << 16,
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| 94 | OPT_o = 1 << 17,
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| 95 | OPT_x = 1 << 18,
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| 96 | OPT_f = 1 << 19,
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| 97 | OPT_B = 1 << 20,
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| 98 | /* The rest has variable bit positions, need to be clever */
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| 99 | OPTBIT_B = 20,
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| 100 | USE_FOR_MMU( OPTBIT_b,)
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| 101 | IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
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| 102 | IF_FEATURE_UDHCP_PORT( OPTBIT_P,)
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| 103 | USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
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| 104 | IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
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| 105 | IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
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| 106 | };
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| 107 |
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| 108 |
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[2725] | 109 | /*** Script execution code ***/
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| 110 |
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| 111 | /* get a rough idea of how long an option will be (rounding up...) */
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[3621] | 112 | static const uint8_t len_of_option_as_string[] ALIGN1 = {
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[2725] | 113 | [OPTION_IP ] = sizeof("255.255.255.255 "),
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| 114 | [OPTION_IP_PAIR ] = sizeof("255.255.255.255 ") * 2,
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| 115 | [OPTION_STATIC_ROUTES ] = sizeof("255.255.255.255/32 255.255.255.255 "),
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[3621] | 116 | [OPTION_6RD ] = sizeof("132 128 ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff 255.255.255.255 "),
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[2725] | 117 | [OPTION_STRING ] = 1,
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[3232] | 118 | [OPTION_STRING_HOST ] = 1,
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[2725] | 119 | #if ENABLE_FEATURE_UDHCP_RFC3397
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| 120 | [OPTION_DNS_STRING ] = 1, /* unused */
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| 121 | /* Hmmm, this severely overestimates size if SIP_SERVERS option
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| 122 | * is in domain name form: N-byte option in binary form
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| 123 | * mallocs ~16*N bytes. But it is freed almost at once.
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| 124 | */
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| 125 | [OPTION_SIP_SERVERS ] = sizeof("255.255.255.255 "),
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| 126 | #endif
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| 127 | // [OPTION_BOOLEAN ] = sizeof("yes "),
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| 128 | [OPTION_U8 ] = sizeof("255 "),
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| 129 | [OPTION_U16 ] = sizeof("65535 "),
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| 130 | // [OPTION_S16 ] = sizeof("-32768 "),
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| 131 | [OPTION_U32 ] = sizeof("4294967295 "),
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| 132 | [OPTION_S32 ] = sizeof("-2147483684 "),
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| 133 | };
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| 134 |
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| 135 | /* note: ip is a pointer to an IP in network order, possibly misaliged */
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| 136 | static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
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| 137 | {
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| 138 | return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
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| 139 | }
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| 140 |
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| 141 | /* really simple implementation, just count the bits */
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| 142 | static int mton(uint32_t mask)
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| 143 | {
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| 144 | int i = 0;
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| 145 | mask = ntohl(mask); /* 111110000-like bit pattern */
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| 146 | while (mask) {
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| 147 | i++;
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| 148 | mask <<= 1;
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| 149 | }
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| 150 | return i;
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| 151 | }
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| 152 |
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[3621] | 153 | #if ENABLE_FEATURE_UDHCPC_SANITIZEOPT
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[3232] | 154 | /* Check if a given label represents a valid DNS label
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| 155 | * Return pointer to the first character after the label upon success,
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| 156 | * NULL otherwise.
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| 157 | * See RFC1035, 2.3.1
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| 158 | */
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| 159 | /* We don't need to be particularly anal. For example, allowing _, hyphen
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| 160 | * at the end, or leading and trailing dots would be ok, since it
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| 161 | * can't be used for attacks. (Leading hyphen can be, if someone uses
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| 162 | * cmd "$hostname"
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| 163 | * in the script: then hostname may be treated as an option)
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| 164 | */
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| 165 | static const char *valid_domain_label(const char *label)
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| 166 | {
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| 167 | unsigned char ch;
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| 168 | unsigned pos = 0;
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| 169 |
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| 170 | for (;;) {
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| 171 | ch = *label;
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| 172 | if ((ch|0x20) < 'a' || (ch|0x20) > 'z') {
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| 173 | if (ch < '0' || ch > '9') {
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| 174 | if (ch == '\0' || ch == '.')
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| 175 | return label;
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| 176 | /* DNS allows only '-', but we are more permissive */
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| 177 | if (ch != '-' && ch != '_')
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| 178 | return NULL;
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| 179 | }
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| 180 | }
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| 181 | label++;
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| 182 | pos++;
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| 183 | //Do we want this?
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| 184 | //if (pos > 63) /* NS_MAXLABEL; labels must be 63 chars or less */
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| 185 | // return NULL;
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| 186 | }
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| 187 | }
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| 188 |
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| 189 | /* Check if a given name represents a valid DNS name */
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| 190 | /* See RFC1035, 2.3.1 */
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| 191 | static int good_hostname(const char *name)
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| 192 | {
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| 193 | //const char *start = name;
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| 194 |
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| 195 | for (;;) {
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| 196 | name = valid_domain_label(name);
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| 197 | if (!name)
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| 198 | return 0;
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| 199 | if (!name[0])
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| 200 | return 1;
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| 201 | //Do we want this?
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| 202 | //return ((name - start) < 1025); /* NS_MAXDNAME */
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| 203 | name++;
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[3621] | 204 | if (*name == '\0')
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| 205 | return 1; // We allow trailing dot too
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[3232] | 206 | }
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| 207 | }
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[3621] | 208 | #else
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| 209 | # define good_hostname(name) 1
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| 210 | #endif
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[3232] | 211 |
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[2725] | 212 | /* Create "opt_name=opt_value" string */
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| 213 | static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_optflag *optflag, const char *opt_name)
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| 214 | {
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| 215 | unsigned upper_length;
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| 216 | int len, type, optlen;
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| 217 | char *dest, *ret;
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| 218 |
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[3232] | 219 | /* option points to OPT_DATA, need to go back to get OPT_LEN */
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| 220 | len = option[-OPT_DATA + OPT_LEN];
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[2725] | 221 |
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| 222 | type = optflag->flags & OPTION_TYPE_MASK;
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| 223 | optlen = dhcp_option_lengths[type];
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[3232] | 224 | upper_length = len_of_option_as_string[type]
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[3621] | 225 | * ((unsigned)(len + optlen) / (unsigned)optlen);
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[2725] | 226 |
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| 227 | dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
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| 228 | dest += sprintf(ret, "%s=", opt_name);
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| 229 |
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| 230 | while (len >= optlen) {
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| 231 | switch (type) {
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[3232] | 232 | case OPTION_IP:
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[2725] | 233 | case OPTION_IP_PAIR:
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| 234 | dest += sprint_nip(dest, "", option);
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[3232] | 235 | if (type == OPTION_IP)
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| 236 | break;
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| 237 | dest += sprint_nip(dest, "/", option + 4);
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[2725] | 238 | break;
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| 239 | // case OPTION_BOOLEAN:
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| 240 | // dest += sprintf(dest, *option ? "yes" : "no");
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| 241 | // break;
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| 242 | case OPTION_U8:
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| 243 | dest += sprintf(dest, "%u", *option);
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| 244 | break;
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| 245 | // case OPTION_S16:
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| 246 | case OPTION_U16: {
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| 247 | uint16_t val_u16;
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| 248 | move_from_unaligned16(val_u16, option);
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| 249 | dest += sprintf(dest, "%u", ntohs(val_u16));
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| 250 | break;
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| 251 | }
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| 252 | case OPTION_S32:
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| 253 | case OPTION_U32: {
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| 254 | uint32_t val_u32;
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| 255 | move_from_unaligned32(val_u32, option);
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| 256 | dest += sprintf(dest, type == OPTION_U32 ? "%lu" : "%ld", (unsigned long) ntohl(val_u32));
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| 257 | break;
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| 258 | }
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[3232] | 259 | /* Note: options which use 'return' instead of 'break'
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| 260 | * (for example, OPTION_STRING) skip the code which handles
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| 261 | * the case of list of options.
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| 262 | */
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[2725] | 263 | case OPTION_STRING:
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[3232] | 264 | case OPTION_STRING_HOST:
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[2725] | 265 | memcpy(dest, option, len);
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| 266 | dest[len] = '\0';
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[3232] | 267 | if (type == OPTION_STRING_HOST && !good_hostname(dest))
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| 268 | safe_strncpy(dest, "bad", len);
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| 269 | return ret;
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[2725] | 270 | case OPTION_STATIC_ROUTES: {
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| 271 | /* Option binary format:
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| 272 | * mask [one byte, 0..32]
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| 273 | * ip [big endian, 0..4 bytes depending on mask]
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| 274 | * router [big endian, 4 bytes]
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| 275 | * may be repeated
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| 276 | *
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| 277 | * We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
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| 278 | */
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| 279 | const char *pfx = "";
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| 280 |
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| 281 | while (len >= 1 + 4) { /* mask + 0-byte ip + router */
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| 282 | uint32_t nip;
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| 283 | uint8_t *p;
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| 284 | unsigned mask;
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| 285 | int bytes;
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| 286 |
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| 287 | mask = *option++;
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| 288 | if (mask > 32)
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| 289 | break;
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| 290 | len--;
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| 291 |
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| 292 | nip = 0;
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| 293 | p = (void*) &nip;
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| 294 | bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
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| 295 | while (--bytes >= 0) {
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| 296 | *p++ = *option++;
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| 297 | len--;
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| 298 | }
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| 299 | if (len < 4)
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| 300 | break;
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| 301 |
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| 302 | /* print ip/mask */
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| 303 | dest += sprint_nip(dest, pfx, (void*) &nip);
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| 304 | pfx = " ";
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| 305 | dest += sprintf(dest, "/%u ", mask);
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| 306 | /* print router */
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| 307 | dest += sprint_nip(dest, "", option);
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| 308 | option += 4;
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| 309 | len -= 4;
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| 310 | }
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| 311 |
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| 312 | return ret;
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| 313 | }
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[3232] | 314 | case OPTION_6RD:
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| 315 | /* Option binary format (see RFC 5969):
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| 316 | * 0 1 2 3
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| 317 | * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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| 318 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 319 | * | OPTION_6RD | option-length | IPv4MaskLen | 6rdPrefixLen |
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| 320 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 321 | * | 6rdPrefix |
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| 322 | * ... (16 octets) ...
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| 323 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 324 | * ... 6rdBRIPv4Address(es) ...
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| 325 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 326 | * We convert it to a string
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| 327 | * "IPv4MaskLen 6rdPrefixLen 6rdPrefix 6rdBRIPv4Address..."
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| 328 | *
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| 329 | * Sanity check: ensure that our length is at least 22 bytes, that
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| 330 | * IPv4MaskLen <= 32,
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| 331 | * 6rdPrefixLen <= 128,
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| 332 | * 6rdPrefixLen + (32 - IPv4MaskLen) <= 128
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| 333 | * (2nd condition need no check - it follows from 1st and 3rd).
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| 334 | * Else, return envvar with empty value ("optname=")
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| 335 | */
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| 336 | if (len >= (1 + 1 + 16 + 4)
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| 337 | && option[0] <= 32
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| 338 | && (option[1] + 32 - option[0]) <= 128
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| 339 | ) {
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| 340 | /* IPv4MaskLen */
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| 341 | dest += sprintf(dest, "%u ", *option++);
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| 342 | /* 6rdPrefixLen */
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| 343 | dest += sprintf(dest, "%u ", *option++);
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| 344 | /* 6rdPrefix */
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| 345 | dest += sprint_nip6(dest, /* "", */ option);
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| 346 | option += 16;
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| 347 | len -= 1 + 1 + 16 + 4;
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| 348 | /* "+ 4" above corresponds to the length of IPv4 addr
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| 349 | * we consume in the loop below */
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| 350 | while (1) {
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| 351 | /* 6rdBRIPv4Address(es) */
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| 352 | dest += sprint_nip(dest, " ", option);
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| 353 | option += 4;
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| 354 | len -= 4; /* do we have yet another 4+ bytes? */
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| 355 | if (len < 0)
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| 356 | break; /* no */
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| 357 | }
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| 358 | }
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| 359 |
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| 360 | return ret;
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[2725] | 361 | #if ENABLE_FEATURE_UDHCP_RFC3397
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| 362 | case OPTION_DNS_STRING:
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| 363 | /* unpack option into dest; use ret for prefix (i.e., "optname=") */
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| 364 | dest = dname_dec(option, len, ret);
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| 365 | if (dest) {
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| 366 | free(ret);
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| 367 | return dest;
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| 368 | }
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| 369 | /* error. return "optname=" string */
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| 370 | return ret;
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| 371 | case OPTION_SIP_SERVERS:
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| 372 | /* Option binary format:
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| 373 | * type: byte
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| 374 | * type=0: domain names, dns-compressed
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| 375 | * type=1: IP addrs
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| 376 | */
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| 377 | option++;
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| 378 | len--;
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| 379 | if (option[-1] == 0) {
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| 380 | dest = dname_dec(option, len, ret);
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| 381 | if (dest) {
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| 382 | free(ret);
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| 383 | return dest;
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| 384 | }
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| 385 | } else
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| 386 | if (option[-1] == 1) {
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| 387 | const char *pfx = "";
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| 388 | while (1) {
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| 389 | len -= 4;
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| 390 | if (len < 0)
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| 391 | break;
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| 392 | dest += sprint_nip(dest, pfx, option);
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| 393 | pfx = " ";
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| 394 | option += 4;
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| 395 | }
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| 396 | }
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| 397 | return ret;
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| 398 | #endif
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| 399 | } /* switch */
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[3232] | 400 |
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| 401 | /* If we are here, try to format any remaining data
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| 402 | * in the option as another, similarly-formatted option
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| 403 | */
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[2725] | 404 | option += optlen;
|
---|
| 405 | len -= optlen;
|
---|
| 406 | // TODO: it can be a list only if (optflag->flags & OPTION_LIST).
|
---|
| 407 | // Should we bail out/warn if we see multi-ip option which is
|
---|
| 408 | // not allowed to be such (for example, DHCP_BROADCAST)? -
|
---|
[3232] | 409 | if (len < optlen /* || !(optflag->flags & OPTION_LIST) */)
|
---|
[2725] | 410 | break;
|
---|
| 411 | *dest++ = ' ';
|
---|
| 412 | *dest = '\0';
|
---|
[3232] | 413 | } /* while */
|
---|
| 414 |
|
---|
[2725] | 415 | return ret;
|
---|
| 416 | }
|
---|
| 417 |
|
---|
| 418 | /* put all the parameters into the environment */
|
---|
| 419 | static char **fill_envp(struct dhcp_packet *packet)
|
---|
| 420 | {
|
---|
| 421 | int envc;
|
---|
| 422 | int i;
|
---|
| 423 | char **envp, **curr;
|
---|
| 424 | const char *opt_name;
|
---|
| 425 | uint8_t *temp;
|
---|
| 426 | uint8_t overload = 0;
|
---|
| 427 |
|
---|
[3232] | 428 | #define BITMAP unsigned
|
---|
| 429 | #define BBITS (sizeof(BITMAP) * 8)
|
---|
| 430 | #define BMASK(i) (1 << (i & (sizeof(BITMAP) * 8 - 1)))
|
---|
| 431 | #define FOUND_OPTS(i) (found_opts[(unsigned)i / BBITS])
|
---|
| 432 | BITMAP found_opts[256 / BBITS];
|
---|
| 433 |
|
---|
| 434 | memset(found_opts, 0, sizeof(found_opts));
|
---|
| 435 |
|
---|
[2725] | 436 | /* We need 6 elements for:
|
---|
| 437 | * "interface=IFACE"
|
---|
| 438 | * "ip=N.N.N.N" from packet->yiaddr
|
---|
| 439 | * "siaddr=IP" from packet->siaddr_nip (unless 0)
|
---|
| 440 | * "boot_file=FILE" from packet->file (unless overloaded)
|
---|
| 441 | * "sname=SERVER_HOSTNAME" from packet->sname (unless overloaded)
|
---|
| 442 | * terminating NULL
|
---|
| 443 | */
|
---|
| 444 | envc = 6;
|
---|
| 445 | /* +1 element for each option, +2 for subnet option: */
|
---|
| 446 | if (packet) {
|
---|
[3232] | 447 | /* note: do not search for "pad" (0) and "end" (255) options */
|
---|
| 448 | //TODO: change logic to scan packet _once_
|
---|
| 449 | for (i = 1; i < 255; i++) {
|
---|
| 450 | temp = udhcp_get_option(packet, i);
|
---|
| 451 | if (temp) {
|
---|
| 452 | if (i == DHCP_OPTION_OVERLOAD)
|
---|
| 453 | overload = *temp;
|
---|
| 454 | else if (i == DHCP_SUBNET)
|
---|
| 455 | envc++; /* for $mask */
|
---|
[2725] | 456 | envc++;
|
---|
[3232] | 457 | /*if (i != DHCP_MESSAGE_TYPE)*/
|
---|
| 458 | FOUND_OPTS(i) |= BMASK(i);
|
---|
[2725] | 459 | }
|
---|
| 460 | }
|
---|
| 461 | }
|
---|
[3232] | 462 | curr = envp = xzalloc(sizeof(envp[0]) * envc);
|
---|
[2725] | 463 |
|
---|
| 464 | *curr = xasprintf("interface=%s", client_config.interface);
|
---|
| 465 | putenv(*curr++);
|
---|
| 466 |
|
---|
| 467 | if (!packet)
|
---|
| 468 | return envp;
|
---|
| 469 |
|
---|
[3232] | 470 | /* Export BOOTP fields. Fields we don't (yet?) export:
|
---|
| 471 | * uint8_t op; // always BOOTREPLY
|
---|
| 472 | * uint8_t htype; // hardware address type. 1 = 10mb ethernet
|
---|
| 473 | * uint8_t hlen; // hardware address length
|
---|
| 474 | * uint8_t hops; // used by relay agents only
|
---|
| 475 | * uint32_t xid;
|
---|
| 476 | * uint16_t secs; // elapsed since client began acquisition/renewal
|
---|
| 477 | * uint16_t flags; // only one flag so far: bcast. Never set by server
|
---|
| 478 | * uint32_t ciaddr; // client IP (usually == yiaddr. can it be different
|
---|
| 479 | * // if during renew server wants to give us differn IP?)
|
---|
| 480 | * uint32_t gateway_nip; // relay agent IP address
|
---|
| 481 | * uint8_t chaddr[16]; // link-layer client hardware address (MAC)
|
---|
| 482 | * TODO: export gateway_nip as $giaddr?
|
---|
| 483 | */
|
---|
| 484 | /* Most important one: yiaddr as $ip */
|
---|
[2725] | 485 | *curr = xmalloc(sizeof("ip=255.255.255.255"));
|
---|
| 486 | sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr);
|
---|
| 487 | putenv(*curr++);
|
---|
[3232] | 488 | if (packet->siaddr_nip) {
|
---|
| 489 | /* IP address of next server to use in bootstrap */
|
---|
| 490 | *curr = xmalloc(sizeof("siaddr=255.255.255.255"));
|
---|
| 491 | sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip);
|
---|
| 492 | putenv(*curr++);
|
---|
| 493 | }
|
---|
| 494 | if (!(overload & FILE_FIELD) && packet->file[0]) {
|
---|
| 495 | /* watch out for invalid packets */
|
---|
| 496 | *curr = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file);
|
---|
| 497 | putenv(*curr++);
|
---|
| 498 | }
|
---|
| 499 | if (!(overload & SNAME_FIELD) && packet->sname[0]) {
|
---|
| 500 | /* watch out for invalid packets */
|
---|
| 501 | *curr = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname);
|
---|
| 502 | putenv(*curr++);
|
---|
| 503 | }
|
---|
[2725] | 504 |
|
---|
[3232] | 505 | /* Export known DHCP options */
|
---|
[2725] | 506 | opt_name = dhcp_option_strings;
|
---|
| 507 | i = 0;
|
---|
| 508 | while (*opt_name) {
|
---|
[3232] | 509 | uint8_t code = dhcp_optflags[i].code;
|
---|
| 510 | BITMAP *found_ptr = &FOUND_OPTS(code);
|
---|
| 511 | BITMAP found_mask = BMASK(code);
|
---|
| 512 | if (!(*found_ptr & found_mask))
|
---|
[2725] | 513 | goto next;
|
---|
[3232] | 514 | *found_ptr &= ~found_mask; /* leave only unknown options */
|
---|
| 515 | temp = udhcp_get_option(packet, code);
|
---|
[2725] | 516 | *curr = xmalloc_optname_optval(temp, &dhcp_optflags[i], opt_name);
|
---|
| 517 | putenv(*curr++);
|
---|
[3232] | 518 | if (code == DHCP_SUBNET) {
|
---|
[2725] | 519 | /* Subnet option: make things like "$ip/$mask" possible */
|
---|
| 520 | uint32_t subnet;
|
---|
| 521 | move_from_unaligned32(subnet, temp);
|
---|
[3232] | 522 | *curr = xasprintf("mask=%u", mton(subnet));
|
---|
[2725] | 523 | putenv(*curr++);
|
---|
| 524 | }
|
---|
| 525 | next:
|
---|
| 526 | opt_name += strlen(opt_name) + 1;
|
---|
| 527 | i++;
|
---|
| 528 | }
|
---|
[3232] | 529 | /* Export unknown options */
|
---|
| 530 | for (i = 0; i < 256;) {
|
---|
| 531 | BITMAP bitmap = FOUND_OPTS(i);
|
---|
| 532 | if (!bitmap) {
|
---|
| 533 | i += BBITS;
|
---|
| 534 | continue;
|
---|
| 535 | }
|
---|
| 536 | if (bitmap & BMASK(i)) {
|
---|
| 537 | unsigned len, ofs;
|
---|
| 538 |
|
---|
| 539 | temp = udhcp_get_option(packet, i);
|
---|
| 540 | /* udhcp_get_option returns ptr to data portion,
|
---|
| 541 | * need to go back to get len
|
---|
| 542 | */
|
---|
| 543 | len = temp[-OPT_DATA + OPT_LEN];
|
---|
| 544 | *curr = xmalloc(sizeof("optNNN=") + 1 + len*2);
|
---|
| 545 | ofs = sprintf(*curr, "opt%u=", i);
|
---|
| 546 | *bin2hex(*curr + ofs, (void*) temp, len) = '\0';
|
---|
| 547 | putenv(*curr++);
|
---|
| 548 | }
|
---|
| 549 | i++;
|
---|
[2725] | 550 | }
|
---|
[3232] | 551 |
|
---|
[2725] | 552 | return envp;
|
---|
| 553 | }
|
---|
| 554 |
|
---|
| 555 | /* Call a script with a par file and env vars */
|
---|
| 556 | static void udhcp_run_script(struct dhcp_packet *packet, const char *name)
|
---|
| 557 | {
|
---|
| 558 | char **envp, **curr;
|
---|
| 559 | char *argv[3];
|
---|
| 560 |
|
---|
| 561 | envp = fill_envp(packet);
|
---|
| 562 |
|
---|
| 563 | /* call script */
|
---|
[3621] | 564 | log1("executing %s %s", client_config.script, name);
|
---|
[2725] | 565 | argv[0] = (char*) client_config.script;
|
---|
| 566 | argv[1] = (char*) name;
|
---|
| 567 | argv[2] = NULL;
|
---|
| 568 | spawn_and_wait(argv);
|
---|
| 569 |
|
---|
| 570 | for (curr = envp; *curr; curr++) {
|
---|
| 571 | log2(" %s", *curr);
|
---|
| 572 | bb_unsetenv_and_free(*curr);
|
---|
| 573 | }
|
---|
| 574 | free(envp);
|
---|
| 575 | }
|
---|
| 576 |
|
---|
| 577 |
|
---|
| 578 | /*** Sending/receiving packets ***/
|
---|
| 579 |
|
---|
| 580 | static ALWAYS_INLINE uint32_t random_xid(void)
|
---|
| 581 | {
|
---|
| 582 | return rand();
|
---|
| 583 | }
|
---|
| 584 |
|
---|
| 585 | /* Initialize the packet with the proper defaults */
|
---|
| 586 | static void init_packet(struct dhcp_packet *packet, char type)
|
---|
| 587 | {
|
---|
[3232] | 588 | uint16_t secs;
|
---|
| 589 |
|
---|
[2725] | 590 | /* Fill in: op, htype, hlen, cookie fields; message type option: */
|
---|
| 591 | udhcp_init_header(packet, type);
|
---|
| 592 |
|
---|
| 593 | packet->xid = random_xid();
|
---|
| 594 |
|
---|
[3232] | 595 | client_config.last_secs = monotonic_sec();
|
---|
| 596 | if (client_config.first_secs == 0)
|
---|
| 597 | client_config.first_secs = client_config.last_secs;
|
---|
| 598 | secs = client_config.last_secs - client_config.first_secs;
|
---|
| 599 | packet->secs = htons(secs);
|
---|
| 600 |
|
---|
[2725] | 601 | memcpy(packet->chaddr, client_config.client_mac, 6);
|
---|
| 602 | if (client_config.clientid)
|
---|
| 603 | udhcp_add_binary_option(packet, client_config.clientid);
|
---|
| 604 | }
|
---|
| 605 |
|
---|
| 606 | static void add_client_options(struct dhcp_packet *packet)
|
---|
| 607 | {
|
---|
| 608 | int i, end, len;
|
---|
| 609 |
|
---|
| 610 | udhcp_add_simple_option(packet, DHCP_MAX_SIZE, htons(IP_UDP_DHCP_SIZE));
|
---|
| 611 |
|
---|
| 612 | /* Add a "param req" option with the list of options we'd like to have
|
---|
| 613 | * from stubborn DHCP servers. Pull the data from the struct in common.c.
|
---|
| 614 | * No bounds checking because it goes towards the head of the packet. */
|
---|
| 615 | end = udhcp_end_option(packet->options);
|
---|
| 616 | len = 0;
|
---|
[3232] | 617 | for (i = 1; i < DHCP_END; i++) {
|
---|
| 618 | if (client_config.opt_mask[i >> 3] & (1 << (i & 7))) {
|
---|
| 619 | packet->options[end + OPT_DATA + len] = i;
|
---|
[2725] | 620 | len++;
|
---|
| 621 | }
|
---|
| 622 | }
|
---|
| 623 | if (len) {
|
---|
| 624 | packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
|
---|
| 625 | packet->options[end + OPT_LEN] = len;
|
---|
| 626 | packet->options[end + OPT_DATA + len] = DHCP_END;
|
---|
| 627 | }
|
---|
| 628 |
|
---|
| 629 | if (client_config.vendorclass)
|
---|
| 630 | udhcp_add_binary_option(packet, client_config.vendorclass);
|
---|
| 631 | if (client_config.hostname)
|
---|
| 632 | udhcp_add_binary_option(packet, client_config.hostname);
|
---|
| 633 | if (client_config.fqdn)
|
---|
| 634 | udhcp_add_binary_option(packet, client_config.fqdn);
|
---|
| 635 |
|
---|
[3232] | 636 | /* Request broadcast replies if we have no IP addr */
|
---|
| 637 | if ((option_mask32 & OPT_B) && packet->ciaddr == 0)
|
---|
| 638 | packet->flags |= htons(BROADCAST_FLAG);
|
---|
| 639 |
|
---|
[2725] | 640 | /* Add -x options if any */
|
---|
| 641 | {
|
---|
| 642 | struct option_set *curr = client_config.options;
|
---|
| 643 | while (curr) {
|
---|
| 644 | udhcp_add_binary_option(packet, curr->data);
|
---|
| 645 | curr = curr->next;
|
---|
| 646 | }
|
---|
| 647 | // if (client_config.sname)
|
---|
| 648 | // strncpy((char*)packet->sname, client_config.sname, sizeof(packet->sname) - 1);
|
---|
| 649 | // if (client_config.boot_file)
|
---|
| 650 | // strncpy((char*)packet->file, client_config.boot_file, sizeof(packet->file) - 1);
|
---|
| 651 | }
|
---|
[3232] | 652 |
|
---|
| 653 | // This will be needed if we remove -V VENDOR_STR in favor of
|
---|
| 654 | // -x vendor:VENDOR_STR
|
---|
| 655 | //if (!udhcp_find_option(packet.options, DHCP_VENDOR))
|
---|
| 656 | // /* not set, set the default vendor ID */
|
---|
| 657 | // ...add (DHCP_VENDOR, "udhcp "BB_VER) opt...
|
---|
[2725] | 658 | }
|
---|
| 659 |
|
---|
| 660 | /* RFC 2131
|
---|
| 661 | * 4.4.4 Use of broadcast and unicast
|
---|
| 662 | *
|
---|
| 663 | * The DHCP client broadcasts DHCPDISCOVER, DHCPREQUEST and DHCPINFORM
|
---|
| 664 | * messages, unless the client knows the address of a DHCP server.
|
---|
| 665 | * The client unicasts DHCPRELEASE messages to the server. Because
|
---|
| 666 | * the client is declining the use of the IP address supplied by the server,
|
---|
| 667 | * the client broadcasts DHCPDECLINE messages.
|
---|
| 668 | *
|
---|
| 669 | * When the DHCP client knows the address of a DHCP server, in either
|
---|
| 670 | * INIT or REBOOTING state, the client may use that address
|
---|
| 671 | * in the DHCPDISCOVER or DHCPREQUEST rather than the IP broadcast address.
|
---|
| 672 | * The client may also use unicast to send DHCPINFORM messages
|
---|
| 673 | * to a known DHCP server. If the client receives no response to DHCP
|
---|
| 674 | * messages sent to the IP address of a known DHCP server, the DHCP
|
---|
| 675 | * client reverts to using the IP broadcast address.
|
---|
[1765] | 676 | */
|
---|
[2725] | 677 |
|
---|
[3621] | 678 | static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet, uint32_t src_nip)
|
---|
[2725] | 679 | {
|
---|
| 680 | return udhcp_send_raw_packet(packet,
|
---|
[3621] | 681 | /*src*/ src_nip, CLIENT_PORT,
|
---|
[2725] | 682 | /*dst*/ INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR,
|
---|
| 683 | client_config.ifindex);
|
---|
| 684 | }
|
---|
| 685 |
|
---|
[3621] | 686 | static int bcast_or_ucast(struct dhcp_packet *packet, uint32_t ciaddr, uint32_t server)
|
---|
| 687 | {
|
---|
| 688 | if (server)
|
---|
| 689 | return udhcp_send_kernel_packet(packet,
|
---|
| 690 | ciaddr, CLIENT_PORT,
|
---|
| 691 | server, SERVER_PORT);
|
---|
| 692 | return raw_bcast_from_client_config_ifindex(packet, ciaddr);
|
---|
| 693 | }
|
---|
| 694 |
|
---|
[2725] | 695 | /* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
|
---|
| 696 | /* NOINLINE: limit stack usage in caller */
|
---|
| 697 | static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
|
---|
| 698 | {
|
---|
| 699 | struct dhcp_packet packet;
|
---|
| 700 |
|
---|
| 701 | /* Fill in: op, htype, hlen, cookie, chaddr fields,
|
---|
| 702 | * random xid field (we override it below),
|
---|
| 703 | * client-id option (unless -C), message type option:
|
---|
| 704 | */
|
---|
| 705 | init_packet(&packet, DHCPDISCOVER);
|
---|
| 706 |
|
---|
| 707 | packet.xid = xid;
|
---|
| 708 | if (requested)
|
---|
| 709 | udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
|
---|
| 710 |
|
---|
| 711 | /* Add options: maxsize,
|
---|
| 712 | * optionally: hostname, fqdn, vendorclass,
|
---|
| 713 | * "param req" option according to -O, options specified with -x
|
---|
| 714 | */
|
---|
| 715 | add_client_options(&packet);
|
---|
| 716 |
|
---|
[3621] | 717 | bb_error_msg("sending %s", "discover");
|
---|
| 718 | return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
|
---|
[2725] | 719 | }
|
---|
| 720 |
|
---|
| 721 | /* Broadcast a DHCP request message */
|
---|
| 722 | /* RFC 2131 3.1 paragraph 3:
|
---|
| 723 | * "The client _broadcasts_ a DHCPREQUEST message..."
|
---|
| 724 | */
|
---|
| 725 | /* NOINLINE: limit stack usage in caller */
|
---|
| 726 | static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requested)
|
---|
| 727 | {
|
---|
| 728 | struct dhcp_packet packet;
|
---|
| 729 | struct in_addr addr;
|
---|
| 730 |
|
---|
| 731 | /*
|
---|
| 732 | * RFC 2131 4.3.2 DHCPREQUEST message
|
---|
| 733 | * ...
|
---|
| 734 | * If the DHCPREQUEST message contains a 'server identifier'
|
---|
| 735 | * option, the message is in response to a DHCPOFFER message.
|
---|
| 736 | * Otherwise, the message is a request to verify or extend an
|
---|
| 737 | * existing lease. If the client uses a 'client identifier'
|
---|
| 738 | * in a DHCPREQUEST message, it MUST use that same 'client identifier'
|
---|
| 739 | * in all subsequent messages. If the client included a list
|
---|
| 740 | * of requested parameters in a DHCPDISCOVER message, it MUST
|
---|
| 741 | * include that list in all subsequent messages.
|
---|
| 742 | */
|
---|
| 743 | /* Fill in: op, htype, hlen, cookie, chaddr fields,
|
---|
| 744 | * random xid field (we override it below),
|
---|
| 745 | * client-id option (unless -C), message type option:
|
---|
| 746 | */
|
---|
| 747 | init_packet(&packet, DHCPREQUEST);
|
---|
| 748 |
|
---|
| 749 | packet.xid = xid;
|
---|
| 750 | udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
|
---|
| 751 |
|
---|
| 752 | udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
|
---|
| 753 |
|
---|
| 754 | /* Add options: maxsize,
|
---|
| 755 | * optionally: hostname, fqdn, vendorclass,
|
---|
| 756 | * "param req" option according to -O, and options specified with -x
|
---|
| 757 | */
|
---|
| 758 | add_client_options(&packet);
|
---|
| 759 |
|
---|
| 760 | addr.s_addr = requested;
|
---|
[3621] | 761 | bb_error_msg("sending select for %s", inet_ntoa(addr));
|
---|
| 762 | return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
|
---|
[2725] | 763 | }
|
---|
| 764 |
|
---|
| 765 | /* Unicast or broadcast a DHCP renew message */
|
---|
| 766 | /* NOINLINE: limit stack usage in caller */
|
---|
| 767 | static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
|
---|
| 768 | {
|
---|
| 769 | struct dhcp_packet packet;
|
---|
| 770 |
|
---|
| 771 | /*
|
---|
| 772 | * RFC 2131 4.3.2 DHCPREQUEST message
|
---|
| 773 | * ...
|
---|
| 774 | * DHCPREQUEST generated during RENEWING state:
|
---|
| 775 | *
|
---|
| 776 | * 'server identifier' MUST NOT be filled in, 'requested IP address'
|
---|
| 777 | * option MUST NOT be filled in, 'ciaddr' MUST be filled in with
|
---|
| 778 | * client's IP address. In this situation, the client is completely
|
---|
| 779 | * configured, and is trying to extend its lease. This message will
|
---|
| 780 | * be unicast, so no relay agents will be involved in its
|
---|
| 781 | * transmission. Because 'giaddr' is therefore not filled in, the
|
---|
| 782 | * DHCP server will trust the value in 'ciaddr', and use it when
|
---|
| 783 | * replying to the client.
|
---|
| 784 | */
|
---|
| 785 | /* Fill in: op, htype, hlen, cookie, chaddr fields,
|
---|
| 786 | * random xid field (we override it below),
|
---|
| 787 | * client-id option (unless -C), message type option:
|
---|
| 788 | */
|
---|
| 789 | init_packet(&packet, DHCPREQUEST);
|
---|
| 790 |
|
---|
| 791 | packet.xid = xid;
|
---|
| 792 | packet.ciaddr = ciaddr;
|
---|
| 793 |
|
---|
| 794 | /* Add options: maxsize,
|
---|
| 795 | * optionally: hostname, fqdn, vendorclass,
|
---|
| 796 | * "param req" option according to -O, and options specified with -x
|
---|
| 797 | */
|
---|
| 798 | add_client_options(&packet);
|
---|
| 799 |
|
---|
[3621] | 800 | bb_error_msg("sending %s", "renew");
|
---|
| 801 | return bcast_or_ucast(&packet, ciaddr, server);
|
---|
[2725] | 802 | }
|
---|
| 803 |
|
---|
| 804 | #if ENABLE_FEATURE_UDHCPC_ARPING
|
---|
| 805 | /* Broadcast a DHCP decline message */
|
---|
| 806 | /* NOINLINE: limit stack usage in caller */
|
---|
[3232] | 807 | static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t requested)
|
---|
[2725] | 808 | {
|
---|
| 809 | struct dhcp_packet packet;
|
---|
| 810 |
|
---|
| 811 | /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
|
---|
| 812 | * client-id option (unless -C), message type option:
|
---|
| 813 | */
|
---|
| 814 | init_packet(&packet, DHCPDECLINE);
|
---|
| 815 |
|
---|
[3232] | 816 | #if 0
|
---|
[2725] | 817 | /* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
|
---|
| 818 | * but in case the server is buggy and wants DHCPDECLINE's xid
|
---|
| 819 | * to match the xid which started entire handshake,
|
---|
| 820 | * we use the same xid we used in initial DHCPDISCOVER:
|
---|
| 821 | */
|
---|
| 822 | packet.xid = xid;
|
---|
[3232] | 823 | #endif
|
---|
[2725] | 824 | /* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
|
---|
| 825 | udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
|
---|
| 826 |
|
---|
| 827 | udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
|
---|
| 828 |
|
---|
[3621] | 829 | bb_error_msg("sending %s", "decline");
|
---|
| 830 | return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
|
---|
[2725] | 831 | }
|
---|
| 832 | #endif
|
---|
| 833 |
|
---|
| 834 | /* Unicast a DHCP release message */
|
---|
| 835 | static int send_release(uint32_t server, uint32_t ciaddr)
|
---|
| 836 | {
|
---|
| 837 | struct dhcp_packet packet;
|
---|
| 838 |
|
---|
| 839 | /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
|
---|
| 840 | * client-id option (unless -C), message type option:
|
---|
| 841 | */
|
---|
| 842 | init_packet(&packet, DHCPRELEASE);
|
---|
| 843 |
|
---|
| 844 | /* DHCPRELEASE uses ciaddr, not "requested ip", to store IP being released */
|
---|
| 845 | packet.ciaddr = ciaddr;
|
---|
| 846 |
|
---|
| 847 | udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
|
---|
| 848 |
|
---|
[3621] | 849 | bb_error_msg("sending %s", "release");
|
---|
| 850 | /* Note: normally we unicast here since "server" is not zero.
|
---|
| 851 | * However, there _are_ people who run "address-less" DHCP servers,
|
---|
| 852 | * and reportedly ISC dhcp client and Windows allow that.
|
---|
| 853 | */
|
---|
| 854 | return bcast_or_ucast(&packet, ciaddr, server);
|
---|
[2725] | 855 | }
|
---|
| 856 |
|
---|
| 857 | /* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */
|
---|
| 858 | /* NOINLINE: limit stack usage in caller */
|
---|
| 859 | static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
|
---|
| 860 | {
|
---|
| 861 | int bytes;
|
---|
| 862 | struct ip_udp_dhcp_packet packet;
|
---|
| 863 | uint16_t check;
|
---|
[3232] | 864 | unsigned char cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
|
---|
| 865 | struct iovec iov;
|
---|
| 866 | struct msghdr msg;
|
---|
[3621] | 867 | struct cmsghdr *cmsg;
|
---|
[2725] | 868 |
|
---|
[3232] | 869 | /* used to use just safe_read(fd, &packet, sizeof(packet))
|
---|
| 870 | * but we need to check for TP_STATUS_CSUMNOTREADY :(
|
---|
| 871 | */
|
---|
| 872 | iov.iov_base = &packet;
|
---|
| 873 | iov.iov_len = sizeof(packet);
|
---|
| 874 | memset(&msg, 0, sizeof(msg));
|
---|
| 875 | msg.msg_iov = &iov;
|
---|
| 876 | msg.msg_iovlen = 1;
|
---|
| 877 | msg.msg_control = cmsgbuf;
|
---|
| 878 | msg.msg_controllen = sizeof(cmsgbuf);
|
---|
| 879 | for (;;) {
|
---|
| 880 | bytes = recvmsg(fd, &msg, 0);
|
---|
| 881 | if (bytes < 0) {
|
---|
| 882 | if (errno == EINTR)
|
---|
| 883 | continue;
|
---|
[3621] | 884 | log1("packet read error, ignoring");
|
---|
[3232] | 885 | /* NB: possible down interface, etc. Caller should pause. */
|
---|
| 886 | return bytes; /* returns -1 */
|
---|
| 887 | }
|
---|
| 888 | break;
|
---|
[2725] | 889 | }
|
---|
| 890 |
|
---|
| 891 | if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) {
|
---|
[3621] | 892 | log1("packet is too short, ignoring");
|
---|
[2725] | 893 | return -2;
|
---|
| 894 | }
|
---|
| 895 |
|
---|
| 896 | if (bytes < ntohs(packet.ip.tot_len)) {
|
---|
| 897 | /* packet is bigger than sizeof(packet), we did partial read */
|
---|
[3621] | 898 | log1("oversized packet, ignoring");
|
---|
[2725] | 899 | return -2;
|
---|
| 900 | }
|
---|
| 901 |
|
---|
| 902 | /* ignore any extra garbage bytes */
|
---|
| 903 | bytes = ntohs(packet.ip.tot_len);
|
---|
| 904 |
|
---|
| 905 | /* make sure its the right packet for us, and that it passes sanity checks */
|
---|
[3232] | 906 | if (packet.ip.protocol != IPPROTO_UDP
|
---|
| 907 | || packet.ip.version != IPVERSION
|
---|
[2725] | 908 | || packet.ip.ihl != (sizeof(packet.ip) >> 2)
|
---|
| 909 | || packet.udp.dest != htons(CLIENT_PORT)
|
---|
| 910 | /* || bytes > (int) sizeof(packet) - can't happen */
|
---|
| 911 | || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip))
|
---|
| 912 | ) {
|
---|
[3621] | 913 | log1("unrelated/bogus packet, ignoring");
|
---|
[2725] | 914 | return -2;
|
---|
| 915 | }
|
---|
| 916 |
|
---|
| 917 | /* verify IP checksum */
|
---|
| 918 | check = packet.ip.check;
|
---|
| 919 | packet.ip.check = 0;
|
---|
[3232] | 920 | if (check != inet_cksum((uint16_t *)&packet.ip, sizeof(packet.ip))) {
|
---|
[3621] | 921 | log1("bad IP header checksum, ignoring");
|
---|
[2725] | 922 | return -2;
|
---|
| 923 | }
|
---|
| 924 |
|
---|
[3232] | 925 | for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
|
---|
| 926 | if (cmsg->cmsg_level == SOL_PACKET
|
---|
| 927 | && cmsg->cmsg_type == PACKET_AUXDATA
|
---|
| 928 | ) {
|
---|
| 929 | /* some VMs don't checksum UDP and TCP data
|
---|
| 930 | * they send to the same physical machine,
|
---|
| 931 | * here we detect this case:
|
---|
| 932 | */
|
---|
| 933 | struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
|
---|
| 934 | if (aux->tp_status & TP_STATUS_CSUMNOTREADY)
|
---|
| 935 | goto skip_udp_sum_check;
|
---|
| 936 | }
|
---|
| 937 | }
|
---|
| 938 |
|
---|
[2725] | 939 | /* verify UDP checksum. IP header has to be modified for this */
|
---|
| 940 | memset(&packet.ip, 0, offsetof(struct iphdr, protocol));
|
---|
| 941 | /* ip.xx fields which are not memset: protocol, check, saddr, daddr */
|
---|
| 942 | packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
|
---|
| 943 | check = packet.udp.check;
|
---|
| 944 | packet.udp.check = 0;
|
---|
[3232] | 945 | if (check && check != inet_cksum((uint16_t *)&packet, bytes)) {
|
---|
[3621] | 946 | log1("packet with bad UDP checksum received, ignoring");
|
---|
[2725] | 947 | return -2;
|
---|
| 948 | }
|
---|
[3232] | 949 | skip_udp_sum_check:
|
---|
[2725] | 950 |
|
---|
[3232] | 951 | if (packet.data.cookie != htonl(DHCP_MAGIC)) {
|
---|
[3621] | 952 | bb_error_msg("packet with bad magic, ignoring");
|
---|
[2725] | 953 | return -2;
|
---|
| 954 | }
|
---|
[3232] | 955 |
|
---|
[3621] | 956 | log1("received %s", "a packet");
|
---|
[3232] | 957 | udhcp_dump_packet(&packet.data);
|
---|
| 958 |
|
---|
| 959 | bytes -= sizeof(packet.ip) + sizeof(packet.udp);
|
---|
| 960 | memcpy(dhcp_pkt, &packet.data, bytes);
|
---|
| 961 | return bytes;
|
---|
[2725] | 962 | }
|
---|
| 963 |
|
---|
| 964 |
|
---|
| 965 | /*** Main ***/
|
---|
| 966 |
|
---|
[1765] | 967 | static int sockfd = -1;
|
---|
[821] | 968 |
|
---|
[2725] | 969 | #define LISTEN_NONE 0
|
---|
[821] | 970 | #define LISTEN_KERNEL 1
|
---|
[2725] | 971 | #define LISTEN_RAW 2
|
---|
[1765] | 972 | static smallint listen_mode;
|
---|
[821] | 973 |
|
---|
[2725] | 974 | /* initial state: (re)start DHCP negotiation */
|
---|
| 975 | #define INIT_SELECTING 0
|
---|
| 976 | /* discover was sent, DHCPOFFER reply received */
|
---|
| 977 | #define REQUESTING 1
|
---|
| 978 | /* select/renew was sent, DHCPACK reply received */
|
---|
| 979 | #define BOUND 2
|
---|
| 980 | /* half of lease passed, want to renew it by sending unicast renew requests */
|
---|
| 981 | #define RENEWING 3
|
---|
| 982 | /* renew requests were not answered, lease is almost over, send broadcast renew */
|
---|
| 983 | #define REBINDING 4
|
---|
| 984 | /* manually requested renew (SIGUSR1) */
|
---|
| 985 | #define RENEW_REQUESTED 5
|
---|
| 986 | /* release, possibly manually requested (SIGUSR2) */
|
---|
| 987 | #define RELEASED 6
|
---|
[1765] | 988 | static smallint state;
|
---|
[821] | 989 |
|
---|
[2725] | 990 | static int udhcp_raw_socket(int ifindex)
|
---|
| 991 | {
|
---|
| 992 | int fd;
|
---|
| 993 | struct sockaddr_ll sock;
|
---|
[1765] | 994 |
|
---|
[3621] | 995 | log1("opening raw socket on ifindex %d", ifindex); //log2?
|
---|
[1765] | 996 |
|
---|
[2725] | 997 | fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
|
---|
[3621] | 998 | /* ^^^^^
|
---|
| 999 | * SOCK_DGRAM: remove link-layer headers on input (SOCK_RAW keeps them)
|
---|
| 1000 | * ETH_P_IP: want to receive only packets with IPv4 eth type
|
---|
| 1001 | */
|
---|
| 1002 | log1("got raw socket fd"); //log2?
|
---|
[2725] | 1003 |
|
---|
[3232] | 1004 | sock.sll_family = AF_PACKET;
|
---|
| 1005 | sock.sll_protocol = htons(ETH_P_IP);
|
---|
| 1006 | sock.sll_ifindex = ifindex;
|
---|
| 1007 | xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
|
---|
| 1008 |
|
---|
[3621] | 1009 | #if 0 /* Several users reported breakage when BPF filter is used */
|
---|
[3232] | 1010 | if (CLIENT_PORT == 68) {
|
---|
| 1011 | /* Use only if standard port is in use */
|
---|
[3621] | 1012 | /*
|
---|
| 1013 | * I've selected not to see LL header, so BPF doesn't see it, too.
|
---|
| 1014 | * The filter may also pass non-IP and non-ARP packets, but we do
|
---|
| 1015 | * a more complete check when receiving the message in userspace.
|
---|
| 1016 | *
|
---|
| 1017 | * and filter shamelessly stolen from:
|
---|
| 1018 | *
|
---|
| 1019 | * http://www.flamewarmaster.de/software/dhcpclient/
|
---|
| 1020 | *
|
---|
| 1021 | * There are a few other interesting ideas on that page (look under
|
---|
| 1022 | * "Motivation"). Use of netlink events is most interesting. Think
|
---|
| 1023 | * of various network servers listening for events and reconfiguring.
|
---|
| 1024 | * That would obsolete sending HUP signals and/or make use of restarts.
|
---|
| 1025 | *
|
---|
| 1026 | * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
|
---|
| 1027 | * License: GPL v2.
|
---|
| 1028 | */
|
---|
| 1029 | static const struct sock_filter filter_instr[] = {
|
---|
| 1030 | /* load 9th byte (protocol) */
|
---|
| 1031 | BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
|
---|
| 1032 | /* jump to L1 if it is IPPROTO_UDP, else to L4 */
|
---|
| 1033 | BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 0, 6),
|
---|
| 1034 | /* L1: load halfword from offset 6 (flags and frag offset) */
|
---|
| 1035 | BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 6),
|
---|
| 1036 | /* jump to L4 if any bits in frag offset field are set, else to L2 */
|
---|
| 1037 | BPF_JUMP(BPF_JMP|BPF_JSET|BPF_K, 0x1fff, 4, 0),
|
---|
| 1038 | /* L2: skip IP header (load index reg with header len) */
|
---|
| 1039 | BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0),
|
---|
| 1040 | /* load udp destination port from halfword[header_len + 2] */
|
---|
| 1041 | BPF_STMT(BPF_LD|BPF_H|BPF_IND, 2),
|
---|
| 1042 | /* jump to L3 if udp dport is CLIENT_PORT, else to L4 */
|
---|
| 1043 | BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
|
---|
| 1044 | /* L3: accept packet ("accept 0x7fffffff bytes") */
|
---|
| 1045 | /* Accepting 0xffffffff works too but kernel 2.6.19 is buggy */
|
---|
| 1046 | BPF_STMT(BPF_RET|BPF_K, 0x7fffffff),
|
---|
| 1047 | /* L4: discard packet ("accept zero bytes") */
|
---|
| 1048 | BPF_STMT(BPF_RET|BPF_K, 0),
|
---|
| 1049 | };
|
---|
| 1050 | static const struct sock_fprog filter_prog = {
|
---|
| 1051 | .len = sizeof(filter_instr) / sizeof(filter_instr[0]),
|
---|
| 1052 | /* casting const away: */
|
---|
| 1053 | .filter = (struct sock_filter *) filter_instr,
|
---|
| 1054 | };
|
---|
[2725] | 1055 | /* Ignoring error (kernel may lack support for this) */
|
---|
| 1056 | if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
|
---|
| 1057 | sizeof(filter_prog)) >= 0)
|
---|
[3621] | 1058 | log1("attached filter to raw socket fd"); // log?
|
---|
[2725] | 1059 | }
|
---|
[3621] | 1060 | #endif
|
---|
[2725] | 1061 |
|
---|
[3621] | 1062 | if (setsockopt_1(fd, SOL_PACKET, PACKET_AUXDATA) != 0) {
|
---|
[3232] | 1063 | if (errno != ENOPROTOOPT)
|
---|
[3621] | 1064 | log1("can't set PACKET_AUXDATA on raw socket");
|
---|
[3232] | 1065 | }
|
---|
| 1066 |
|
---|
[3621] | 1067 | log1("created raw socket");
|
---|
[2725] | 1068 |
|
---|
| 1069 | return fd;
|
---|
| 1070 | }
|
---|
| 1071 |
|
---|
| 1072 | static void change_listen_mode(int new_mode)
|
---|
[821] | 1073 | {
|
---|
[3621] | 1074 | log1("entering listen mode: %s",
|
---|
[2725] | 1075 | new_mode != LISTEN_NONE
|
---|
| 1076 | ? (new_mode == LISTEN_KERNEL ? "kernel" : "raw")
|
---|
| 1077 | : "none"
|
---|
| 1078 | );
|
---|
| 1079 |
|
---|
| 1080 | listen_mode = new_mode;
|
---|
[1765] | 1081 | if (sockfd >= 0) {
|
---|
| 1082 | close(sockfd);
|
---|
| 1083 | sockfd = -1;
|
---|
| 1084 | }
|
---|
[2725] | 1085 | if (new_mode == LISTEN_KERNEL)
|
---|
| 1086 | sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
|
---|
| 1087 | else if (new_mode != LISTEN_NONE)
|
---|
| 1088 | sockfd = udhcp_raw_socket(client_config.ifindex);
|
---|
| 1089 | /* else LISTEN_NONE: sockfd stays closed */
|
---|
[821] | 1090 | }
|
---|
| 1091 |
|
---|
[3232] | 1092 | /* Called only on SIGUSR1 */
|
---|
[821] | 1093 | static void perform_renew(void)
|
---|
| 1094 | {
|
---|
[3621] | 1095 | bb_error_msg("performing DHCP renew");
|
---|
[821] | 1096 | switch (state) {
|
---|
| 1097 | case BOUND:
|
---|
[2725] | 1098 | change_listen_mode(LISTEN_KERNEL);
|
---|
[821] | 1099 | case RENEWING:
|
---|
| 1100 | case REBINDING:
|
---|
| 1101 | state = RENEW_REQUESTED;
|
---|
| 1102 | break;
|
---|
| 1103 | case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
|
---|
| 1104 | udhcp_run_script(NULL, "deconfig");
|
---|
| 1105 | case REQUESTING:
|
---|
| 1106 | case RELEASED:
|
---|
[2725] | 1107 | change_listen_mode(LISTEN_RAW);
|
---|
[821] | 1108 | state = INIT_SELECTING;
|
---|
| 1109 | break;
|
---|
| 1110 | case INIT_SELECTING:
|
---|
| 1111 | break;
|
---|
| 1112 | }
|
---|
| 1113 | }
|
---|
| 1114 |
|
---|
[3232] | 1115 | static void perform_release(uint32_t server_addr, uint32_t requested_ip)
|
---|
[821] | 1116 | {
|
---|
[1765] | 1117 | char buffer[sizeof("255.255.255.255")];
|
---|
[821] | 1118 | struct in_addr temp_addr;
|
---|
| 1119 |
|
---|
| 1120 | /* send release packet */
|
---|
| 1121 | if (state == BOUND || state == RENEWING || state == REBINDING) {
|
---|
| 1122 | temp_addr.s_addr = server_addr;
|
---|
[1765] | 1123 | strcpy(buffer, inet_ntoa(temp_addr));
|
---|
[821] | 1124 | temp_addr.s_addr = requested_ip;
|
---|
[3621] | 1125 | bb_error_msg("unicasting a release of %s to %s",
|
---|
[821] | 1126 | inet_ntoa(temp_addr), buffer);
|
---|
| 1127 | send_release(server_addr, requested_ip); /* unicast */
|
---|
| 1128 | udhcp_run_script(NULL, "deconfig");
|
---|
| 1129 | }
|
---|
[3621] | 1130 | bb_error_msg("entering released state");
|
---|
[821] | 1131 |
|
---|
[2725] | 1132 | change_listen_mode(LISTEN_NONE);
|
---|
[821] | 1133 | state = RELEASED;
|
---|
| 1134 | }
|
---|
| 1135 |
|
---|
[1765] | 1136 | static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
|
---|
[821] | 1137 | {
|
---|
[1765] | 1138 | uint8_t *storage;
|
---|
[2725] | 1139 | int len = strnlen(str, 255);
|
---|
[1765] | 1140 | storage = xzalloc(len + extra + OPT_DATA);
|
---|
| 1141 | storage[OPT_CODE] = code;
|
---|
| 1142 | storage[OPT_LEN] = len + extra;
|
---|
| 1143 | memcpy(storage + extra + OPT_DATA, str, len);
|
---|
| 1144 | return storage;
|
---|
| 1145 | }
|
---|
| 1146 |
|
---|
[2725] | 1147 | #if BB_MMU
|
---|
| 1148 | static void client_background(void)
|
---|
| 1149 | {
|
---|
| 1150 | bb_daemonize(0);
|
---|
| 1151 | logmode &= ~LOGMODE_STDIO;
|
---|
| 1152 | /* rewrite pidfile, as our pid is different now */
|
---|
| 1153 | write_pidfile(client_config.pidfile);
|
---|
| 1154 | }
|
---|
| 1155 | #endif
|
---|
[1765] | 1156 |
|
---|
[2725] | 1157 | //usage:#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
|
---|
| 1158 | //usage:# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
|
---|
| 1159 | //usage:#else
|
---|
| 1160 | //usage:# define IF_UDHCP_VERBOSE(...)
|
---|
| 1161 | //usage:#endif
|
---|
| 1162 | //usage:#define udhcpc_trivial_usage
|
---|
[3621] | 1163 | //usage: "[-fbq"IF_UDHCP_VERBOSE("v")"RB]"IF_FEATURE_UDHCPC_ARPING(" [-a[MSEC]]")" [-t N] [-T SEC] [-A SEC/-n]\n"
|
---|
| 1164 | //usage: " [-i IFACE]"IF_FEATURE_UDHCP_PORT(" [-P PORT]")" [-s PROG] [-p PIDFILE]\n"
|
---|
| 1165 | //usage: " [-oC] [-r IP] [-V VENDOR] [-F NAME] [-x OPT:VAL]... [-O OPT]..."
|
---|
[2725] | 1166 | //usage:#define udhcpc_full_usage "\n"
|
---|
| 1167 | //usage: IF_LONG_OPTS(
|
---|
| 1168 | //usage: "\n -i,--interface IFACE Interface to use (default eth0)"
|
---|
[3621] | 1169 | //usage: IF_FEATURE_UDHCP_PORT(
|
---|
| 1170 | //usage: "\n -P,--client-port PORT Use PORT (default 68)"
|
---|
| 1171 | //usage: )
|
---|
| 1172 | //usage: "\n -s,--script PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
|
---|
[2725] | 1173 | //usage: "\n -p,--pidfile FILE Create pidfile"
|
---|
[3232] | 1174 | //usage: "\n -B,--broadcast Request broadcast replies"
|
---|
[3621] | 1175 | //usage: "\n -t,--retries N Send up to N discover packets (default 3)"
|
---|
| 1176 | //usage: "\n -T,--timeout SEC Pause between packets (default 3)"
|
---|
| 1177 | //usage: "\n -A,--tryagain SEC Wait if lease is not obtained (default 20)"
|
---|
| 1178 | //usage: "\n -n,--now Exit if lease is not obtained"
|
---|
| 1179 | //usage: "\n -q,--quit Exit after obtaining lease"
|
---|
| 1180 | //usage: "\n -R,--release Release IP on exit"
|
---|
[2725] | 1181 | //usage: "\n -f,--foreground Run in foreground"
|
---|
| 1182 | //usage: USE_FOR_MMU(
|
---|
| 1183 | //usage: "\n -b,--background Background if lease is not obtained"
|
---|
| 1184 | //usage: )
|
---|
| 1185 | //usage: "\n -S,--syslog Log to syslog too"
|
---|
| 1186 | //usage: IF_FEATURE_UDHCPC_ARPING(
|
---|
[3621] | 1187 | //usage: "\n -a[MSEC],--arping[=MSEC] Validate offered address with ARP ping"
|
---|
[2725] | 1188 | //usage: )
|
---|
[3621] | 1189 | //usage: "\n -r,--request IP Request this IP address"
|
---|
| 1190 | //usage: "\n -o,--no-default-options Don't request any options (unless -O is given)"
|
---|
[2725] | 1191 | //usage: "\n -O,--request-option OPT Request option OPT from server (cumulative)"
|
---|
| 1192 | //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
|
---|
| 1193 | //usage: "\n Examples of string, numeric, and hex byte opts:"
|
---|
| 1194 | //usage: "\n -x hostname:bbox - option 12"
|
---|
| 1195 | //usage: "\n -x lease:3600 - option 51 (lease time)"
|
---|
| 1196 | //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
|
---|
| 1197 | //usage: "\n -F,--fqdn NAME Ask server to update DNS mapping for NAME"
|
---|
| 1198 | //usage: "\n -V,--vendorclass VENDOR Vendor identifier (default 'udhcp VERSION')"
|
---|
| 1199 | //usage: "\n -C,--clientid-none Don't send MAC as client identifier"
|
---|
| 1200 | //usage: IF_UDHCP_VERBOSE(
|
---|
| 1201 | //usage: "\n -v Verbose"
|
---|
| 1202 | //usage: )
|
---|
| 1203 | //usage: )
|
---|
| 1204 | //usage: IF_NOT_LONG_OPTS(
|
---|
| 1205 | //usage: "\n -i IFACE Interface to use (default eth0)"
|
---|
[3621] | 1206 | //usage: IF_FEATURE_UDHCP_PORT(
|
---|
| 1207 | //usage: "\n -P PORT Use PORT (default 68)"
|
---|
| 1208 | //usage: )
|
---|
| 1209 | //usage: "\n -s PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
|
---|
[2725] | 1210 | //usage: "\n -p FILE Create pidfile"
|
---|
[3232] | 1211 | //usage: "\n -B Request broadcast replies"
|
---|
[3621] | 1212 | //usage: "\n -t N Send up to N discover packets (default 3)"
|
---|
| 1213 | //usage: "\n -T SEC Pause between packets (default 3)"
|
---|
| 1214 | //usage: "\n -A SEC Wait if lease is not obtained (default 20)"
|
---|
| 1215 | //usage: "\n -n Exit if lease is not obtained"
|
---|
| 1216 | //usage: "\n -q Exit after obtaining lease"
|
---|
| 1217 | //usage: "\n -R Release IP on exit"
|
---|
[2725] | 1218 | //usage: "\n -f Run in foreground"
|
---|
| 1219 | //usage: USE_FOR_MMU(
|
---|
| 1220 | //usage: "\n -b Background if lease is not obtained"
|
---|
| 1221 | //usage: )
|
---|
| 1222 | //usage: "\n -S Log to syslog too"
|
---|
| 1223 | //usage: IF_FEATURE_UDHCPC_ARPING(
|
---|
[3621] | 1224 | //usage: "\n -a[MSEC] Validate offered address with ARP ping"
|
---|
[2725] | 1225 | //usage: )
|
---|
[3621] | 1226 | //usage: "\n -r IP Request this IP address"
|
---|
| 1227 | //usage: "\n -o Don't request any options (unless -O is given)"
|
---|
[2725] | 1228 | //usage: "\n -O OPT Request option OPT from server (cumulative)"
|
---|
| 1229 | //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
|
---|
| 1230 | //usage: "\n Examples of string, numeric, and hex byte opts:"
|
---|
| 1231 | //usage: "\n -x hostname:bbox - option 12"
|
---|
| 1232 | //usage: "\n -x lease:3600 - option 51 (lease time)"
|
---|
| 1233 | //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
|
---|
| 1234 | //usage: "\n -F NAME Ask server to update DNS mapping for NAME"
|
---|
| 1235 | //usage: "\n -V VENDOR Vendor identifier (default 'udhcp VERSION')"
|
---|
| 1236 | //usage: "\n -C Don't send MAC as client identifier"
|
---|
| 1237 | //usage: IF_UDHCP_VERBOSE(
|
---|
| 1238 | //usage: "\n -v Verbose"
|
---|
| 1239 | //usage: )
|
---|
| 1240 | //usage: )
|
---|
[3232] | 1241 | //usage: "\nSignals:"
|
---|
| 1242 | //usage: "\n USR1 Renew lease"
|
---|
| 1243 | //usage: "\n USR2 Release lease"
|
---|
[2725] | 1244 |
|
---|
[3232] | 1245 |
|
---|
[2725] | 1246 | int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
---|
| 1247 | int udhcpc_main(int argc UNUSED_PARAM, char **argv)
|
---|
[1765] | 1248 | {
|
---|
[3621] | 1249 | uint8_t *message;
|
---|
[2725] | 1250 | const char *str_V, *str_h, *str_F, *str_r;
|
---|
[3621] | 1251 | IF_FEATURE_UDHCPC_ARPING(const char *str_a = "2000";)
|
---|
[2725] | 1252 | IF_FEATURE_UDHCP_PORT(char *str_P;)
|
---|
| 1253 | void *clientid_mac_ptr;
|
---|
| 1254 | llist_t *list_O = NULL;
|
---|
| 1255 | llist_t *list_x = NULL;
|
---|
| 1256 | int tryagain_timeout = 20;
|
---|
| 1257 | int discover_timeout = 3;
|
---|
| 1258 | int discover_retries = 3;
|
---|
| 1259 | uint32_t server_addr = server_addr; /* for compiler */
|
---|
| 1260 | uint32_t requested_ip = 0;
|
---|
[3232] | 1261 | uint32_t xid = xid; /* for compiler */
|
---|
[2725] | 1262 | int packet_num;
|
---|
| 1263 | int timeout; /* must be signed */
|
---|
| 1264 | unsigned already_waited_sec;
|
---|
[1765] | 1265 | unsigned opt;
|
---|
[3621] | 1266 | IF_FEATURE_UDHCPC_ARPING(unsigned arpping_ms;)
|
---|
[1765] | 1267 | int max_fd;
|
---|
[821] | 1268 | int retval;
|
---|
[1765] | 1269 | fd_set rfds;
|
---|
[821] | 1270 |
|
---|
[3621] | 1271 | setup_common_bufsiz();
|
---|
| 1272 |
|
---|
[2725] | 1273 | /* Default options */
|
---|
| 1274 | IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
|
---|
| 1275 | IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
|
---|
[1765] | 1276 | client_config.interface = "eth0";
|
---|
[2725] | 1277 | client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
|
---|
| 1278 | str_V = "udhcp "BB_VER;
|
---|
[821] | 1279 |
|
---|
[1765] | 1280 | /* Parse command line */
|
---|
[2725] | 1281 | /* O,x: list; -T,-t,-A take numeric param */
|
---|
[3232] | 1282 | opt_complementary = "O::x::T+:t+:A+" IF_UDHCP_VERBOSE(":vv") ;
|
---|
[2725] | 1283 | IF_LONG_OPTS(applet_long_options = udhcpc_longopts;)
|
---|
[3232] | 1284 | opt = getopt32(argv, "CV:H:h:F:i:np:qRr:s:T:t:SA:O:ox:fB"
|
---|
[2725] | 1285 | USE_FOR_MMU("b")
|
---|
[3621] | 1286 | IF_FEATURE_UDHCPC_ARPING("a::")
|
---|
[2725] | 1287 | IF_FEATURE_UDHCP_PORT("P:")
|
---|
| 1288 | "v"
|
---|
| 1289 | , &str_V, &str_h, &str_h, &str_F
|
---|
| 1290 | , &client_config.interface, &client_config.pidfile, &str_r /* i,p */
|
---|
| 1291 | , &client_config.script /* s */
|
---|
| 1292 | , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
|
---|
| 1293 | , &list_O
|
---|
| 1294 | , &list_x
|
---|
[3621] | 1295 | IF_FEATURE_UDHCPC_ARPING(, &str_a)
|
---|
[2725] | 1296 | IF_FEATURE_UDHCP_PORT(, &str_P)
|
---|
[3232] | 1297 | IF_UDHCP_VERBOSE(, &dhcp_verbose)
|
---|
| 1298 | );
|
---|
| 1299 | if (opt & (OPT_h|OPT_H)) {
|
---|
| 1300 | //msg added 2011-11
|
---|
| 1301 | bb_error_msg("option -h NAME is deprecated, use -x hostname:NAME");
|
---|
[1765] | 1302 | client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
|
---|
[3232] | 1303 | }
|
---|
[1765] | 1304 | if (opt & OPT_F) {
|
---|
[2725] | 1305 | /* FQDN option format: [0x51][len][flags][0][0]<fqdn> */
|
---|
[1765] | 1306 | client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
|
---|
[2725] | 1307 | /* Flag bits: 0000NEOS
|
---|
| 1308 | * S: 1 = Client requests server to update A RR in DNS as well as PTR
|
---|
| 1309 | * O: 1 = Server indicates to client that DNS has been updated regardless
|
---|
| 1310 | * E: 1 = Name is in DNS format, i.e. <4>host<6>domain<3>com<0>,
|
---|
| 1311 | * not "host.domain.com". Format 0 is obsolete.
|
---|
| 1312 | * N: 1 = Client requests server to not update DNS (S must be 0 then)
|
---|
| 1313 | * Two [0] bytes which follow are deprecated and must be 0.
|
---|
| 1314 | */
|
---|
[1765] | 1315 | client_config.fqdn[OPT_DATA + 0] = 0x1;
|
---|
[2725] | 1316 | /*client_config.fqdn[OPT_DATA + 1] = 0; - xzalloc did it */
|
---|
| 1317 | /*client_config.fqdn[OPT_DATA + 2] = 0; */
|
---|
[821] | 1318 | }
|
---|
[1765] | 1319 | if (opt & OPT_r)
|
---|
| 1320 | requested_ip = inet_addr(str_r);
|
---|
[2725] | 1321 | #if ENABLE_FEATURE_UDHCP_PORT
|
---|
| 1322 | if (opt & OPT_P) {
|
---|
| 1323 | CLIENT_PORT = xatou16(str_P);
|
---|
| 1324 | SERVER_PORT = CLIENT_PORT - 1;
|
---|
[1765] | 1325 | }
|
---|
[2725] | 1326 | #endif
|
---|
[3621] | 1327 | IF_FEATURE_UDHCPC_ARPING(arpping_ms = xatou(str_a);)
|
---|
[2725] | 1328 | while (list_O) {
|
---|
| 1329 | char *optstr = llist_pop(&list_O);
|
---|
[3232] | 1330 | unsigned n = bb_strtou(optstr, NULL, 0);
|
---|
| 1331 | if (errno || n > 254) {
|
---|
| 1332 | n = udhcp_option_idx(optstr);
|
---|
| 1333 | n = dhcp_optflags[n].code;
|
---|
| 1334 | }
|
---|
[2725] | 1335 | client_config.opt_mask[n >> 3] |= 1 << (n & 7);
|
---|
| 1336 | }
|
---|
[3232] | 1337 | if (!(opt & OPT_o)) {
|
---|
| 1338 | unsigned i, n;
|
---|
| 1339 | for (i = 0; (n = dhcp_optflags[i].code) != 0; i++) {
|
---|
| 1340 | if (dhcp_optflags[i].flags & OPTION_REQ) {
|
---|
| 1341 | client_config.opt_mask[n >> 3] |= 1 << (n & 7);
|
---|
| 1342 | }
|
---|
| 1343 | }
|
---|
| 1344 | }
|
---|
[2725] | 1345 | while (list_x) {
|
---|
| 1346 | char *optstr = llist_pop(&list_x);
|
---|
| 1347 | char *colon = strchr(optstr, ':');
|
---|
| 1348 | if (colon)
|
---|
| 1349 | *colon = ' ';
|
---|
| 1350 | /* now it looks similar to udhcpd's config file line:
|
---|
| 1351 | * "optname optval", using the common routine: */
|
---|
| 1352 | udhcp_str2optset(optstr, &client_config.options);
|
---|
| 1353 | }
|
---|
[821] | 1354 |
|
---|
[2725] | 1355 | if (udhcp_read_interface(client_config.interface,
|
---|
| 1356 | &client_config.ifindex,
|
---|
| 1357 | NULL,
|
---|
| 1358 | client_config.client_mac)
|
---|
| 1359 | ) {
|
---|
| 1360 | return 1;
|
---|
| 1361 | }
|
---|
| 1362 |
|
---|
| 1363 | clientid_mac_ptr = NULL;
|
---|
| 1364 | if (!(opt & OPT_C) && !udhcp_find_option(client_config.options, DHCP_CLIENT_ID)) {
|
---|
| 1365 | /* not suppressed and not set, set the default client ID */
|
---|
| 1366 | client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
|
---|
| 1367 | client_config.clientid[OPT_DATA] = 1; /* type: ethernet */
|
---|
| 1368 | clientid_mac_ptr = client_config.clientid + OPT_DATA+1;
|
---|
| 1369 | memcpy(clientid_mac_ptr, client_config.client_mac, 6);
|
---|
| 1370 | }
|
---|
[3232] | 1371 | if (str_V[0] != '\0') {
|
---|
| 1372 | // can drop -V, str_V, client_config.vendorclass,
|
---|
| 1373 | // but need to add "vendor" to the list of recognized
|
---|
| 1374 | // string opts for this to work;
|
---|
| 1375 | // and need to tweak add_client_options() too...
|
---|
| 1376 | // ...so the question is, should we?
|
---|
| 1377 | //bb_error_msg("option -V VENDOR is deprecated, use -x vendor:VENDOR");
|
---|
[2725] | 1378 | client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
|
---|
[3232] | 1379 | }
|
---|
| 1380 |
|
---|
[2725] | 1381 | #if !BB_MMU
|
---|
| 1382 | /* on NOMMU reexec (i.e., background) early */
|
---|
| 1383 | if (!(opt & OPT_f)) {
|
---|
| 1384 | bb_daemonize_or_rexec(0 /* flags */, argv);
|
---|
| 1385 | logmode = LOGMODE_NONE;
|
---|
| 1386 | }
|
---|
| 1387 | #endif
|
---|
[1765] | 1388 | if (opt & OPT_S) {
|
---|
[2725] | 1389 | openlog(applet_name, LOG_PID, LOG_DAEMON);
|
---|
[1765] | 1390 | logmode |= LOGMODE_SYSLOG;
|
---|
| 1391 | }
|
---|
[821] | 1392 |
|
---|
[1765] | 1393 | /* Make sure fd 0,1,2 are open */
|
---|
| 1394 | bb_sanitize_stdio();
|
---|
| 1395 | /* Equivalent of doing a fflush after every \n */
|
---|
| 1396 | setlinebuf(stdout);
|
---|
| 1397 | /* Create pidfile */
|
---|
| 1398 | write_pidfile(client_config.pidfile);
|
---|
[2725] | 1399 | /* Goes to stdout (unless NOMMU) and possibly syslog */
|
---|
[3621] | 1400 | bb_error_msg("started, v"BB_VER);
|
---|
[2725] | 1401 | /* Set up the signal pipe */
|
---|
[821] | 1402 | udhcp_sp_setup();
|
---|
[2725] | 1403 | /* We want random_xid to be random... */
|
---|
| 1404 | srand(monotonic_us());
|
---|
[821] | 1405 |
|
---|
| 1406 | state = INIT_SELECTING;
|
---|
| 1407 | udhcp_run_script(NULL, "deconfig");
|
---|
[2725] | 1408 | change_listen_mode(LISTEN_RAW);
|
---|
| 1409 | packet_num = 0;
|
---|
| 1410 | timeout = 0;
|
---|
| 1411 | already_waited_sec = 0;
|
---|
[821] | 1412 |
|
---|
[2725] | 1413 | /* Main event loop. select() waits on signal pipe and possibly
|
---|
| 1414 | * on sockfd.
|
---|
| 1415 | * "continue" statements in code below jump to the top of the loop.
|
---|
| 1416 | */
|
---|
[821] | 1417 | for (;;) {
|
---|
[3232] | 1418 | struct timeval tv;
|
---|
| 1419 | struct dhcp_packet packet;
|
---|
[2725] | 1420 | /* silence "uninitialized!" warning */
|
---|
| 1421 | unsigned timestamp_before_wait = timestamp_before_wait;
|
---|
[821] | 1422 |
|
---|
[2725] | 1423 | //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
|
---|
| 1424 |
|
---|
| 1425 | /* Was opening raw or udp socket here
|
---|
| 1426 | * if (listen_mode != LISTEN_NONE && sockfd < 0),
|
---|
| 1427 | * but on fast network renew responses return faster
|
---|
| 1428 | * than we open sockets. Thus this code is moved
|
---|
| 1429 | * to change_listen_mode(). Thus we open listen socket
|
---|
| 1430 | * BEFORE we send renew request (see "case BOUND:"). */
|
---|
| 1431 |
|
---|
[1765] | 1432 | max_fd = udhcp_sp_fd_set(&rfds, sockfd);
|
---|
[821] | 1433 |
|
---|
[2725] | 1434 | tv.tv_sec = timeout - already_waited_sec;
|
---|
| 1435 | tv.tv_usec = 0;
|
---|
| 1436 | retval = 0;
|
---|
| 1437 | /* If we already timed out, fall through with retval = 0, else... */
|
---|
| 1438 | if ((int)tv.tv_sec > 0) {
|
---|
[3621] | 1439 | log1("waiting on select %u seconds", (int)tv.tv_sec);
|
---|
[2725] | 1440 | timestamp_before_wait = (unsigned)monotonic_sec();
|
---|
[821] | 1441 | retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
|
---|
[2725] | 1442 | if (retval < 0) {
|
---|
| 1443 | /* EINTR? A signal was caught, don't panic */
|
---|
| 1444 | if (errno == EINTR) {
|
---|
| 1445 | already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
|
---|
| 1446 | continue;
|
---|
| 1447 | }
|
---|
[1765] | 1448 | /* Else: an error occured, panic! */
|
---|
| 1449 | bb_perror_msg_and_die("select");
|
---|
| 1450 | }
|
---|
[2725] | 1451 | }
|
---|
| 1452 |
|
---|
| 1453 | /* If timeout dropped to zero, time to become active:
|
---|
| 1454 | * resend discover/renew/whatever
|
---|
| 1455 | */
|
---|
| 1456 | if (retval == 0) {
|
---|
| 1457 | /* When running on a bridge, the ifindex may have changed
|
---|
| 1458 | * (e.g. if member interfaces were added/removed
|
---|
| 1459 | * or if the status of the bridge changed).
|
---|
| 1460 | * Refresh ifindex and client_mac:
|
---|
| 1461 | */
|
---|
| 1462 | if (udhcp_read_interface(client_config.interface,
|
---|
| 1463 | &client_config.ifindex,
|
---|
| 1464 | NULL,
|
---|
| 1465 | client_config.client_mac)
|
---|
| 1466 | ) {
|
---|
[3232] | 1467 | goto ret0; /* iface is gone? */
|
---|
[2725] | 1468 | }
|
---|
| 1469 | if (clientid_mac_ptr)
|
---|
| 1470 | memcpy(clientid_mac_ptr, client_config.client_mac, 6);
|
---|
| 1471 |
|
---|
| 1472 | /* We will restart the wait in any case */
|
---|
| 1473 | already_waited_sec = 0;
|
---|
| 1474 |
|
---|
[821] | 1475 | switch (state) {
|
---|
| 1476 | case INIT_SELECTING:
|
---|
[3232] | 1477 | if (!discover_retries || packet_num < discover_retries) {
|
---|
[821] | 1478 | if (packet_num == 0)
|
---|
| 1479 | xid = random_xid();
|
---|
[2725] | 1480 | /* broadcast */
|
---|
| 1481 | send_discover(xid, requested_ip);
|
---|
| 1482 | timeout = discover_timeout;
|
---|
[821] | 1483 | packet_num++;
|
---|
[2725] | 1484 | continue;
|
---|
[821] | 1485 | }
|
---|
[2725] | 1486 | leasefail:
|
---|
| 1487 | udhcp_run_script(NULL, "leasefail");
|
---|
| 1488 | #if BB_MMU /* -b is not supported on NOMMU */
|
---|
| 1489 | if (opt & OPT_b) { /* background if no lease */
|
---|
[3621] | 1490 | bb_error_msg("no lease, forking to background");
|
---|
[2725] | 1491 | client_background();
|
---|
| 1492 | /* do not background again! */
|
---|
| 1493 | opt = ((opt & ~OPT_b) | OPT_f);
|
---|
| 1494 | } else
|
---|
| 1495 | #endif
|
---|
| 1496 | if (opt & OPT_n) { /* abort if no lease */
|
---|
[3621] | 1497 | bb_error_msg("no lease, failing");
|
---|
[2725] | 1498 | retval = 1;
|
---|
| 1499 | goto ret;
|
---|
| 1500 | }
|
---|
| 1501 | /* wait before trying again */
|
---|
| 1502 | timeout = tryagain_timeout;
|
---|
| 1503 | packet_num = 0;
|
---|
| 1504 | continue;
|
---|
[821] | 1505 | case REQUESTING:
|
---|
[3621] | 1506 | if (packet_num < 3) {
|
---|
[2725] | 1507 | /* send broadcast select packet */
|
---|
| 1508 | send_select(xid, server_addr, requested_ip);
|
---|
| 1509 | timeout = discover_timeout;
|
---|
[821] | 1510 | packet_num++;
|
---|
[2725] | 1511 | continue;
|
---|
[821] | 1512 | }
|
---|
[2725] | 1513 | /* Timed out, go back to init state.
|
---|
| 1514 | * "discover...select...discover..." loops
|
---|
| 1515 | * were seen in the wild. Treat them similarly
|
---|
| 1516 | * to "no response to discover" case */
|
---|
| 1517 | change_listen_mode(LISTEN_RAW);
|
---|
| 1518 | state = INIT_SELECTING;
|
---|
| 1519 | goto leasefail;
|
---|
[821] | 1520 | case BOUND:
|
---|
[2725] | 1521 | /* 1/2 lease passed, enter renewing state */
|
---|
[821] | 1522 | state = RENEWING;
|
---|
[3232] | 1523 | client_config.first_secs = 0; /* make secs field count from 0 */
|
---|
[2725] | 1524 | change_listen_mode(LISTEN_KERNEL);
|
---|
[3621] | 1525 | log1("entering renew state");
|
---|
[821] | 1526 | /* fall right through */
|
---|
[2725] | 1527 | case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
|
---|
| 1528 | case_RENEW_REQUESTED:
|
---|
[821] | 1529 | case RENEWING:
|
---|
[2725] | 1530 | if (timeout > 60) {
|
---|
| 1531 | /* send an unicast renew request */
|
---|
| 1532 | /* Sometimes observed to fail (EADDRNOTAVAIL) to bind
|
---|
| 1533 | * a new UDP socket for sending inside send_renew.
|
---|
| 1534 | * I hazard to guess existing listening socket
|
---|
| 1535 | * is somehow conflicting with it, but why is it
|
---|
| 1536 | * not deterministic then?! Strange.
|
---|
| 1537 | * Anyway, it does recover by eventually failing through
|
---|
| 1538 | * into INIT_SELECTING state.
|
---|
| 1539 | */
|
---|
| 1540 | send_renew(xid, server_addr, requested_ip);
|
---|
| 1541 | timeout >>= 1;
|
---|
| 1542 | continue;
|
---|
[821] | 1543 | }
|
---|
[2725] | 1544 | /* Timed out, enter rebinding state */
|
---|
[3621] | 1545 | log1("entering rebinding state");
|
---|
[2725] | 1546 | state = REBINDING;
|
---|
| 1547 | /* fall right through */
|
---|
[821] | 1548 | case REBINDING:
|
---|
[2725] | 1549 | /* Switch to bcast receive */
|
---|
| 1550 | change_listen_mode(LISTEN_RAW);
|
---|
| 1551 | /* Lease is *really* about to run out,
|
---|
| 1552 | * try to find DHCP server using broadcast */
|
---|
| 1553 | if (timeout > 0) {
|
---|
| 1554 | /* send a broadcast renew request */
|
---|
| 1555 | send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
|
---|
| 1556 | timeout >>= 1;
|
---|
| 1557 | continue;
|
---|
[821] | 1558 | }
|
---|
[2725] | 1559 | /* Timed out, enter init state */
|
---|
[3621] | 1560 | bb_error_msg("lease lost, entering init state");
|
---|
[2725] | 1561 | udhcp_run_script(NULL, "deconfig");
|
---|
| 1562 | state = INIT_SELECTING;
|
---|
[3232] | 1563 | client_config.first_secs = 0; /* make secs field count from 0 */
|
---|
[2725] | 1564 | /*timeout = 0; - already is */
|
---|
| 1565 | packet_num = 0;
|
---|
| 1566 | continue;
|
---|
| 1567 | /* case RELEASED: */
|
---|
[821] | 1568 | }
|
---|
[2725] | 1569 | /* yah, I know, *you* say it would never happen */
|
---|
| 1570 | timeout = INT_MAX;
|
---|
| 1571 | continue; /* back to main loop */
|
---|
| 1572 | } /* if select timed out */
|
---|
[821] | 1573 |
|
---|
[2725] | 1574 | /* select() didn't timeout, something happened */
|
---|
[821] | 1575 |
|
---|
[2725] | 1576 | /* Is it a signal? */
|
---|
| 1577 | /* note: udhcp_sp_read checks FD_ISSET before reading */
|
---|
| 1578 | switch (udhcp_sp_read(&rfds)) {
|
---|
| 1579 | case SIGUSR1:
|
---|
[3232] | 1580 | client_config.first_secs = 0; /* make secs field count from 0 */
|
---|
| 1581 | already_waited_sec = 0;
|
---|
[2725] | 1582 | perform_renew();
|
---|
[3232] | 1583 | if (state == RENEW_REQUESTED) {
|
---|
| 1584 | /* We might be either on the same network
|
---|
| 1585 | * (in which case renew might work),
|
---|
| 1586 | * or we might be on a completely different one
|
---|
| 1587 | * (in which case renew won't ever succeed).
|
---|
| 1588 | * For the second case, must make sure timeout
|
---|
| 1589 | * is not too big, or else we can send
|
---|
| 1590 | * futile renew requests for hours.
|
---|
| 1591 | * (Ab)use -A TIMEOUT value (usually 20 sec)
|
---|
| 1592 | * as a cap on the timeout.
|
---|
| 1593 | */
|
---|
| 1594 | if (timeout > tryagain_timeout)
|
---|
| 1595 | timeout = tryagain_timeout;
|
---|
[2725] | 1596 | goto case_RENEW_REQUESTED;
|
---|
[3232] | 1597 | }
|
---|
[2725] | 1598 | /* Start things over */
|
---|
| 1599 | packet_num = 0;
|
---|
| 1600 | /* Kill any timeouts, user wants this to hurry along */
|
---|
| 1601 | timeout = 0;
|
---|
| 1602 | continue;
|
---|
| 1603 | case SIGUSR2:
|
---|
[3232] | 1604 | perform_release(server_addr, requested_ip);
|
---|
[2725] | 1605 | timeout = INT_MAX;
|
---|
| 1606 | continue;
|
---|
| 1607 | case SIGTERM:
|
---|
[3621] | 1608 | bb_error_msg("received %s", "SIGTERM");
|
---|
[2725] | 1609 | goto ret0;
|
---|
| 1610 | }
|
---|
[821] | 1611 |
|
---|
[2725] | 1612 | /* Is it a packet? */
|
---|
| 1613 | if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds))
|
---|
| 1614 | continue; /* no */
|
---|
| 1615 |
|
---|
| 1616 | {
|
---|
| 1617 | int len;
|
---|
| 1618 |
|
---|
| 1619 | /* A packet is ready, read it */
|
---|
| 1620 | if (listen_mode == LISTEN_KERNEL)
|
---|
| 1621 | len = udhcp_recv_kernel_packet(&packet, sockfd);
|
---|
| 1622 | else
|
---|
| 1623 | len = udhcp_recv_raw_packet(&packet, sockfd);
|
---|
| 1624 | if (len == -1) {
|
---|
| 1625 | /* Error is severe, reopen socket */
|
---|
[3621] | 1626 | bb_error_msg("read error: %s, reopening socket", strerror(errno));
|
---|
[2725] | 1627 | sleep(discover_timeout); /* 3 seconds by default */
|
---|
| 1628 | change_listen_mode(listen_mode); /* just close and reopen */
|
---|
[821] | 1629 | }
|
---|
[2725] | 1630 | /* If this packet will turn out to be unrelated/bogus,
|
---|
| 1631 | * we will go back and wait for next one.
|
---|
| 1632 | * Be sure timeout is properly decreased. */
|
---|
| 1633 | already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
|
---|
| 1634 | if (len < 0)
|
---|
[821] | 1635 | continue;
|
---|
[2725] | 1636 | }
|
---|
[821] | 1637 |
|
---|
[2725] | 1638 | if (packet.xid != xid) {
|
---|
| 1639 | log1("xid %x (our is %x), ignoring packet",
|
---|
| 1640 | (unsigned)packet.xid, (unsigned)xid);
|
---|
| 1641 | continue;
|
---|
| 1642 | }
|
---|
| 1643 |
|
---|
| 1644 | /* Ignore packets that aren't for us */
|
---|
| 1645 | if (packet.hlen != 6
|
---|
| 1646 | || memcmp(packet.chaddr, client_config.client_mac, 6) != 0
|
---|
| 1647 | ) {
|
---|
| 1648 | //FIXME: need to also check that last 10 bytes are zero
|
---|
| 1649 | log1("chaddr does not match, ignoring packet"); // log2?
|
---|
| 1650 | continue;
|
---|
| 1651 | }
|
---|
| 1652 |
|
---|
| 1653 | message = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE);
|
---|
| 1654 | if (message == NULL) {
|
---|
| 1655 | bb_error_msg("no message type option, ignoring packet");
|
---|
| 1656 | continue;
|
---|
| 1657 | }
|
---|
| 1658 |
|
---|
| 1659 | switch (state) {
|
---|
| 1660 | case INIT_SELECTING:
|
---|
[3232] | 1661 | /* Must be a DHCPOFFER */
|
---|
[2725] | 1662 | if (*message == DHCPOFFER) {
|
---|
[3621] | 1663 | uint8_t *temp;
|
---|
| 1664 |
|
---|
[3232] | 1665 | /* What exactly is server's IP? There are several values.
|
---|
| 1666 | * Example DHCP offer captured with tchdump:
|
---|
| 1667 | *
|
---|
| 1668 | * 10.34.25.254:67 > 10.34.25.202:68 // IP header's src
|
---|
| 1669 | * BOOTP fields:
|
---|
| 1670 | * Your-IP 10.34.25.202
|
---|
| 1671 | * Server-IP 10.34.32.125 // "next server" IP
|
---|
| 1672 | * Gateway-IP 10.34.25.254 // relay's address (if DHCP relays are in use)
|
---|
| 1673 | * DHCP options:
|
---|
| 1674 | * DHCP-Message Option 53, length 1: Offer
|
---|
| 1675 | * Server-ID Option 54, length 4: 10.34.255.7 // "server ID"
|
---|
| 1676 | * Default-Gateway Option 3, length 4: 10.34.25.254 // router
|
---|
| 1677 | *
|
---|
| 1678 | * We think that real server IP (one to use in renew/release)
|
---|
| 1679 | * is one in Server-ID option. But I am not 100% sure.
|
---|
| 1680 | * IP header's src and Gateway-IP (same in this example)
|
---|
| 1681 | * might work too.
|
---|
| 1682 | * "Next server" and router are definitely wrong ones to use, though...
|
---|
| 1683 | */
|
---|
[3621] | 1684 | /* We used to ignore pcakets without DHCP_SERVER_ID.
|
---|
| 1685 | * I've got user reports from people who run "address-less" servers.
|
---|
| 1686 | * They either supply DHCP_SERVER_ID of 0.0.0.0 or don't supply it at all.
|
---|
| 1687 | * They say ISC DHCP client supports this case.
|
---|
| 1688 | */
|
---|
| 1689 | server_addr = 0;
|
---|
[2725] | 1690 | temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
|
---|
| 1691 | if (!temp) {
|
---|
[3621] | 1692 | bb_error_msg("no server ID, using 0.0.0.0");
|
---|
| 1693 | } else {
|
---|
| 1694 | /* it IS unaligned sometimes, don't "optimize" */
|
---|
| 1695 | move_from_unaligned32(server_addr, temp);
|
---|
[2725] | 1696 | }
|
---|
| 1697 | /*xid = packet.xid; - already is */
|
---|
| 1698 | requested_ip = packet.yiaddr;
|
---|
| 1699 |
|
---|
| 1700 | /* enter requesting state */
|
---|
| 1701 | state = REQUESTING;
|
---|
| 1702 | timeout = 0;
|
---|
| 1703 | packet_num = 0;
|
---|
| 1704 | already_waited_sec = 0;
|
---|
[821] | 1705 | }
|
---|
[2725] | 1706 | continue;
|
---|
| 1707 | case REQUESTING:
|
---|
| 1708 | case RENEWING:
|
---|
| 1709 | case RENEW_REQUESTED:
|
---|
| 1710 | case REBINDING:
|
---|
| 1711 | if (*message == DHCPACK) {
|
---|
[3621] | 1712 | unsigned start;
|
---|
[3232] | 1713 | uint32_t lease_seconds;
|
---|
| 1714 | struct in_addr temp_addr;
|
---|
[3621] | 1715 | uint8_t *temp;
|
---|
[3232] | 1716 |
|
---|
[2725] | 1717 | temp = udhcp_get_option(&packet, DHCP_LEASE_TIME);
|
---|
| 1718 | if (!temp) {
|
---|
| 1719 | bb_error_msg("no lease time with ACK, using 1 hour lease");
|
---|
| 1720 | lease_seconds = 60 * 60;
|
---|
| 1721 | } else {
|
---|
| 1722 | /* it IS unaligned sometimes, don't "optimize" */
|
---|
| 1723 | move_from_unaligned32(lease_seconds, temp);
|
---|
| 1724 | lease_seconds = ntohl(lease_seconds);
|
---|
[3232] | 1725 | /* paranoia: must not be too small and not prone to overflows */
|
---|
| 1726 | if (lease_seconds < 0x10)
|
---|
| 1727 | lease_seconds = 0x10;
|
---|
| 1728 | if (lease_seconds >= 0x10000000)
|
---|
| 1729 | lease_seconds = 0x0fffffff;
|
---|
[2725] | 1730 | }
|
---|
| 1731 | #if ENABLE_FEATURE_UDHCPC_ARPING
|
---|
| 1732 | if (opt & OPT_a) {
|
---|
| 1733 | /* RFC 2131 3.1 paragraph 5:
|
---|
| 1734 | * "The client receives the DHCPACK message with configuration
|
---|
| 1735 | * parameters. The client SHOULD perform a final check on the
|
---|
| 1736 | * parameters (e.g., ARP for allocated network address), and notes
|
---|
| 1737 | * the duration of the lease specified in the DHCPACK message. At this
|
---|
| 1738 | * point, the client is configured. If the client detects that the
|
---|
| 1739 | * address is already in use (e.g., through the use of ARP),
|
---|
| 1740 | * the client MUST send a DHCPDECLINE message to the server and restarts
|
---|
| 1741 | * the configuration process..." */
|
---|
| 1742 | if (!arpping(packet.yiaddr,
|
---|
| 1743 | NULL,
|
---|
| 1744 | (uint32_t) 0,
|
---|
| 1745 | client_config.client_mac,
|
---|
[3621] | 1746 | client_config.interface,
|
---|
| 1747 | arpping_ms)
|
---|
[2725] | 1748 | ) {
|
---|
[3621] | 1749 | bb_error_msg("offered address is in use "
|
---|
[2725] | 1750 | "(got ARP reply), declining");
|
---|
[3232] | 1751 | send_decline(/*xid,*/ server_addr, packet.yiaddr);
|
---|
[821] | 1752 |
|
---|
[2725] | 1753 | if (state != REQUESTING)
|
---|
| 1754 | udhcp_run_script(NULL, "deconfig");
|
---|
| 1755 | change_listen_mode(LISTEN_RAW);
|
---|
| 1756 | state = INIT_SELECTING;
|
---|
[3232] | 1757 | client_config.first_secs = 0; /* make secs field count from 0 */
|
---|
[2725] | 1758 | requested_ip = 0;
|
---|
| 1759 | timeout = tryagain_timeout;
|
---|
[821] | 1760 | packet_num = 0;
|
---|
[2725] | 1761 | already_waited_sec = 0;
|
---|
| 1762 | continue; /* back to main loop */
|
---|
[821] | 1763 | }
|
---|
| 1764 | }
|
---|
[2725] | 1765 | #endif
|
---|
| 1766 | /* enter bound state */
|
---|
[3232] | 1767 | temp_addr.s_addr = packet.yiaddr;
|
---|
[3621] | 1768 | bb_error_msg("lease of %s obtained, lease time %u",
|
---|
[3232] | 1769 | inet_ntoa(temp_addr), (unsigned)lease_seconds);
|
---|
[2725] | 1770 | requested_ip = packet.yiaddr;
|
---|
[3621] | 1771 |
|
---|
| 1772 | start = monotonic_sec();
|
---|
[2725] | 1773 | udhcp_run_script(&packet, state == REQUESTING ? "bound" : "renew");
|
---|
[3621] | 1774 | already_waited_sec = (unsigned)monotonic_sec() - start;
|
---|
| 1775 | timeout = lease_seconds / 2;
|
---|
| 1776 | if ((unsigned)timeout < already_waited_sec) {
|
---|
| 1777 | /* Something went wrong. Back to discover state */
|
---|
| 1778 | timeout = already_waited_sec = 0;
|
---|
| 1779 | }
|
---|
[821] | 1780 |
|
---|
[2725] | 1781 | state = BOUND;
|
---|
| 1782 | change_listen_mode(LISTEN_NONE);
|
---|
| 1783 | if (opt & OPT_q) { /* quit after lease */
|
---|
| 1784 | goto ret0;
|
---|
[821] | 1785 | }
|
---|
[2725] | 1786 | /* future renew failures should not exit (JM) */
|
---|
| 1787 | opt &= ~OPT_n;
|
---|
| 1788 | #if BB_MMU /* NOMMU case backgrounded earlier */
|
---|
| 1789 | if (!(opt & OPT_f)) {
|
---|
| 1790 | client_background();
|
---|
| 1791 | /* do not background again! */
|
---|
| 1792 | opt = ((opt & ~OPT_b) | OPT_f);
|
---|
| 1793 | }
|
---|
| 1794 | #endif
|
---|
[3232] | 1795 | /* make future renew packets use different xid */
|
---|
| 1796 | /* xid = random_xid(); ...but why bother? */
|
---|
[3621] | 1797 |
|
---|
[2725] | 1798 | continue; /* back to main loop */
|
---|
[821] | 1799 | }
|
---|
[2725] | 1800 | if (*message == DHCPNAK) {
|
---|
[3621] | 1801 | /* If network has more than one DHCP server,
|
---|
| 1802 | * "wrong" server can reply first, with a NAK.
|
---|
| 1803 | * Do not interpret it as a NAK from "our" server.
|
---|
| 1804 | */
|
---|
| 1805 | if (server_addr != 0) {
|
---|
| 1806 | uint32_t svid;
|
---|
| 1807 | uint8_t *temp;
|
---|
| 1808 |
|
---|
| 1809 | temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
|
---|
| 1810 | if (!temp) {
|
---|
| 1811 | non_matching_svid:
|
---|
| 1812 | log1("%s with wrong server ID, ignoring packet",
|
---|
| 1813 | "Received DHCP NAK"
|
---|
| 1814 | );
|
---|
| 1815 | continue;
|
---|
| 1816 | }
|
---|
| 1817 | move_from_unaligned32(svid, temp);
|
---|
| 1818 | if (svid != server_addr)
|
---|
| 1819 | goto non_matching_svid;
|
---|
| 1820 | }
|
---|
[2725] | 1821 | /* return to init state */
|
---|
[3621] | 1822 | bb_error_msg("received %s", "DHCP NAK");
|
---|
[2725] | 1823 | udhcp_run_script(&packet, "nak");
|
---|
| 1824 | if (state != REQUESTING)
|
---|
| 1825 | udhcp_run_script(NULL, "deconfig");
|
---|
| 1826 | change_listen_mode(LISTEN_RAW);
|
---|
| 1827 | sleep(3); /* avoid excessive network traffic */
|
---|
| 1828 | state = INIT_SELECTING;
|
---|
[3232] | 1829 | client_config.first_secs = 0; /* make secs field count from 0 */
|
---|
[2725] | 1830 | requested_ip = 0;
|
---|
| 1831 | timeout = 0;
|
---|
| 1832 | packet_num = 0;
|
---|
| 1833 | already_waited_sec = 0;
|
---|
[821] | 1834 | }
|
---|
[2725] | 1835 | continue;
|
---|
| 1836 | /* case BOUND: - ignore all packets */
|
---|
| 1837 | /* case RELEASED: - ignore all packets */
|
---|
[821] | 1838 | }
|
---|
[2725] | 1839 | /* back to main loop */
|
---|
| 1840 | } /* for (;;) - main loop ends */
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| 1841 |
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[1765] | 1842 | ret0:
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[3232] | 1843 | if (opt & OPT_R) /* release on quit */
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| 1844 | perform_release(server_addr, requested_ip);
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[1765] | 1845 | retval = 0;
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| 1846 | ret:
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[2725] | 1847 | /*if (client_config.pidfile) - remove_pidfile has its own check */
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[1765] | 1848 | remove_pidfile(client_config.pidfile);
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| 1849 | return retval;
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[821] | 1850 | }
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