[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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[3626] | 29 | // BCO for RHEL4
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| 30 | #include <linux/types.h>
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| 31 | // BCO
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[2725] | 32 | #include <linux/filter.h>
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[3621] | 33 | #include <linux/if_packet.h>
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[1765] | 34 |
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[3621] | 35 | #ifndef PACKET_AUXDATA
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| 36 | # define PACKET_AUXDATA 8
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| 37 | struct tpacket_auxdata {
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| 38 | uint32_t tp_status;
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| 39 | uint32_t tp_len;
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| 40 | uint32_t tp_snaplen;
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| 41 | uint16_t tp_mac;
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| 42 | uint16_t tp_net;
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| 43 | uint16_t tp_vlan_tci;
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| 44 | uint16_t tp_padding;
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| 45 | };
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| 46 | #endif
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| 47 |
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| 48 |
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[3232] | 49 | /* "struct client_config_t client_config" is in bb_common_bufsiz1 */
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[2725] | 50 |
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| 51 |
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[3232] | 52 | #if ENABLE_LONG_OPTS
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| 53 | static const char udhcpc_longopts[] ALIGN1 =
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| 54 | "clientid-none\0" No_argument "C"
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| 55 | "vendorclass\0" Required_argument "V"
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| 56 | "hostname\0" Required_argument "H"
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| 57 | "fqdn\0" Required_argument "F"
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| 58 | "interface\0" Required_argument "i"
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| 59 | "now\0" No_argument "n"
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| 60 | "pidfile\0" Required_argument "p"
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| 61 | "quit\0" No_argument "q"
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| 62 | "release\0" No_argument "R"
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| 63 | "request\0" Required_argument "r"
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| 64 | "script\0" Required_argument "s"
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| 65 | "timeout\0" Required_argument "T"
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| 66 | "retries\0" Required_argument "t"
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| 67 | "tryagain\0" Required_argument "A"
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| 68 | "syslog\0" No_argument "S"
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| 69 | "request-option\0" Required_argument "O"
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| 70 | "no-default-options\0" No_argument "o"
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| 71 | "foreground\0" No_argument "f"
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| 72 | "background\0" No_argument "b"
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| 73 | "broadcast\0" No_argument "B"
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[3621] | 74 | IF_FEATURE_UDHCPC_ARPING("arping\0" Optional_argument "a")
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[3232] | 75 | IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
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| 76 | ;
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| 77 | #endif
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| 78 | /* Must match getopt32 option string order */
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| 79 | enum {
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| 80 | OPT_C = 1 << 0,
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| 81 | OPT_V = 1 << 1,
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| 82 | OPT_H = 1 << 2,
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| 83 | OPT_h = 1 << 3,
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| 84 | OPT_F = 1 << 4,
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| 85 | OPT_i = 1 << 5,
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| 86 | OPT_n = 1 << 6,
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| 87 | OPT_p = 1 << 7,
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| 88 | OPT_q = 1 << 8,
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| 89 | OPT_R = 1 << 9,
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| 90 | OPT_r = 1 << 10,
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| 91 | OPT_s = 1 << 11,
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| 92 | OPT_T = 1 << 12,
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| 93 | OPT_t = 1 << 13,
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| 94 | OPT_S = 1 << 14,
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| 95 | OPT_A = 1 << 15,
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| 96 | OPT_O = 1 << 16,
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| 97 | OPT_o = 1 << 17,
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| 98 | OPT_x = 1 << 18,
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| 99 | OPT_f = 1 << 19,
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| 100 | OPT_B = 1 << 20,
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| 101 | /* The rest has variable bit positions, need to be clever */
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| 102 | OPTBIT_B = 20,
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| 103 | USE_FOR_MMU( OPTBIT_b,)
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| 104 | IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
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| 105 | IF_FEATURE_UDHCP_PORT( OPTBIT_P,)
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| 106 | USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
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| 107 | IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
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| 108 | IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
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| 109 | };
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| 110 |
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| 111 |
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[2725] | 112 | /*** Script execution code ***/
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| 113 |
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| 114 | /* get a rough idea of how long an option will be (rounding up...) */
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[3621] | 115 | static const uint8_t len_of_option_as_string[] ALIGN1 = {
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[2725] | 116 | [OPTION_IP ] = sizeof("255.255.255.255 "),
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| 117 | [OPTION_IP_PAIR ] = sizeof("255.255.255.255 ") * 2,
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| 118 | [OPTION_STATIC_ROUTES ] = sizeof("255.255.255.255/32 255.255.255.255 "),
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[3621] | 119 | [OPTION_6RD ] = sizeof("132 128 ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff 255.255.255.255 "),
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[2725] | 120 | [OPTION_STRING ] = 1,
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[3232] | 121 | [OPTION_STRING_HOST ] = 1,
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[2725] | 122 | #if ENABLE_FEATURE_UDHCP_RFC3397
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| 123 | [OPTION_DNS_STRING ] = 1, /* unused */
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| 124 | /* Hmmm, this severely overestimates size if SIP_SERVERS option
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| 125 | * is in domain name form: N-byte option in binary form
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| 126 | * mallocs ~16*N bytes. But it is freed almost at once.
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| 127 | */
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| 128 | [OPTION_SIP_SERVERS ] = sizeof("255.255.255.255 "),
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| 129 | #endif
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| 130 | // [OPTION_BOOLEAN ] = sizeof("yes "),
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| 131 | [OPTION_U8 ] = sizeof("255 "),
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| 132 | [OPTION_U16 ] = sizeof("65535 "),
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| 133 | // [OPTION_S16 ] = sizeof("-32768 "),
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| 134 | [OPTION_U32 ] = sizeof("4294967295 "),
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| 135 | [OPTION_S32 ] = sizeof("-2147483684 "),
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| 136 | };
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| 137 |
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| 138 | /* note: ip is a pointer to an IP in network order, possibly misaliged */
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| 139 | static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
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| 140 | {
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| 141 | return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
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| 142 | }
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| 143 |
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| 144 | /* really simple implementation, just count the bits */
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| 145 | static int mton(uint32_t mask)
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| 146 | {
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| 147 | int i = 0;
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| 148 | mask = ntohl(mask); /* 111110000-like bit pattern */
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| 149 | while (mask) {
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| 150 | i++;
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| 151 | mask <<= 1;
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| 152 | }
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| 153 | return i;
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| 154 | }
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| 155 |
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[3621] | 156 | #if ENABLE_FEATURE_UDHCPC_SANITIZEOPT
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[3232] | 157 | /* Check if a given label represents a valid DNS label
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| 158 | * Return pointer to the first character after the label upon success,
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| 159 | * NULL otherwise.
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| 160 | * See RFC1035, 2.3.1
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| 161 | */
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| 162 | /* We don't need to be particularly anal. For example, allowing _, hyphen
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| 163 | * at the end, or leading and trailing dots would be ok, since it
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| 164 | * can't be used for attacks. (Leading hyphen can be, if someone uses
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| 165 | * cmd "$hostname"
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| 166 | * in the script: then hostname may be treated as an option)
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| 167 | */
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| 168 | static const char *valid_domain_label(const char *label)
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| 169 | {
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| 170 | unsigned char ch;
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| 171 | unsigned pos = 0;
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| 172 |
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| 173 | for (;;) {
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| 174 | ch = *label;
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| 175 | if ((ch|0x20) < 'a' || (ch|0x20) > 'z') {
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| 176 | if (ch < '0' || ch > '9') {
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| 177 | if (ch == '\0' || ch == '.')
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| 178 | return label;
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| 179 | /* DNS allows only '-', but we are more permissive */
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| 180 | if (ch != '-' && ch != '_')
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| 181 | return NULL;
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| 182 | }
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| 183 | }
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| 184 | label++;
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| 185 | pos++;
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| 186 | //Do we want this?
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| 187 | //if (pos > 63) /* NS_MAXLABEL; labels must be 63 chars or less */
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| 188 | // return NULL;
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| 189 | }
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| 190 | }
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| 191 |
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| 192 | /* Check if a given name represents a valid DNS name */
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| 193 | /* See RFC1035, 2.3.1 */
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| 194 | static int good_hostname(const char *name)
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| 195 | {
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| 196 | //const char *start = name;
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| 197 |
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| 198 | for (;;) {
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| 199 | name = valid_domain_label(name);
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| 200 | if (!name)
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| 201 | return 0;
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| 202 | if (!name[0])
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| 203 | return 1;
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| 204 | //Do we want this?
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| 205 | //return ((name - start) < 1025); /* NS_MAXDNAME */
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| 206 | name++;
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[3621] | 207 | if (*name == '\0')
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| 208 | return 1; // We allow trailing dot too
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[3232] | 209 | }
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| 210 | }
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[3621] | 211 | #else
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| 212 | # define good_hostname(name) 1
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| 213 | #endif
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[3232] | 214 |
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[2725] | 215 | /* Create "opt_name=opt_value" string */
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| 216 | static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_optflag *optflag, const char *opt_name)
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| 217 | {
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| 218 | unsigned upper_length;
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| 219 | int len, type, optlen;
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| 220 | char *dest, *ret;
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| 221 |
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[3232] | 222 | /* option points to OPT_DATA, need to go back to get OPT_LEN */
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| 223 | len = option[-OPT_DATA + OPT_LEN];
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[2725] | 224 |
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| 225 | type = optflag->flags & OPTION_TYPE_MASK;
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| 226 | optlen = dhcp_option_lengths[type];
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[3232] | 227 | upper_length = len_of_option_as_string[type]
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[3621] | 228 | * ((unsigned)(len + optlen) / (unsigned)optlen);
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[2725] | 229 |
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| 230 | dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
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| 231 | dest += sprintf(ret, "%s=", opt_name);
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| 232 |
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| 233 | while (len >= optlen) {
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| 234 | switch (type) {
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[3232] | 235 | case OPTION_IP:
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[2725] | 236 | case OPTION_IP_PAIR:
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| 237 | dest += sprint_nip(dest, "", option);
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[3232] | 238 | if (type == OPTION_IP)
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| 239 | break;
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| 240 | dest += sprint_nip(dest, "/", option + 4);
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[2725] | 241 | break;
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| 242 | // case OPTION_BOOLEAN:
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| 243 | // dest += sprintf(dest, *option ? "yes" : "no");
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| 244 | // break;
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| 245 | case OPTION_U8:
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| 246 | dest += sprintf(dest, "%u", *option);
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| 247 | break;
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| 248 | // case OPTION_S16:
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| 249 | case OPTION_U16: {
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| 250 | uint16_t val_u16;
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| 251 | move_from_unaligned16(val_u16, option);
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| 252 | dest += sprintf(dest, "%u", ntohs(val_u16));
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| 253 | break;
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| 254 | }
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| 255 | case OPTION_S32:
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| 256 | case OPTION_U32: {
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| 257 | uint32_t val_u32;
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| 258 | move_from_unaligned32(val_u32, option);
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| 259 | dest += sprintf(dest, type == OPTION_U32 ? "%lu" : "%ld", (unsigned long) ntohl(val_u32));
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| 260 | break;
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| 261 | }
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[3232] | 262 | /* Note: options which use 'return' instead of 'break'
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| 263 | * (for example, OPTION_STRING) skip the code which handles
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| 264 | * the case of list of options.
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| 265 | */
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[2725] | 266 | case OPTION_STRING:
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[3232] | 267 | case OPTION_STRING_HOST:
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[2725] | 268 | memcpy(dest, option, len);
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| 269 | dest[len] = '\0';
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[3232] | 270 | if (type == OPTION_STRING_HOST && !good_hostname(dest))
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| 271 | safe_strncpy(dest, "bad", len);
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| 272 | return ret;
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[2725] | 273 | case OPTION_STATIC_ROUTES: {
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| 274 | /* Option binary format:
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| 275 | * mask [one byte, 0..32]
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| 276 | * ip [big endian, 0..4 bytes depending on mask]
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| 277 | * router [big endian, 4 bytes]
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| 278 | * may be repeated
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| 279 | *
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| 280 | * We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
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| 281 | */
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| 282 | const char *pfx = "";
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| 283 |
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| 284 | while (len >= 1 + 4) { /* mask + 0-byte ip + router */
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| 285 | uint32_t nip;
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| 286 | uint8_t *p;
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| 287 | unsigned mask;
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| 288 | int bytes;
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| 289 |
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| 290 | mask = *option++;
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| 291 | if (mask > 32)
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| 292 | break;
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| 293 | len--;
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| 294 |
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| 295 | nip = 0;
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| 296 | p = (void*) &nip;
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| 297 | bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
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| 298 | while (--bytes >= 0) {
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| 299 | *p++ = *option++;
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| 300 | len--;
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| 301 | }
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| 302 | if (len < 4)
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| 303 | break;
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| 304 |
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| 305 | /* print ip/mask */
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| 306 | dest += sprint_nip(dest, pfx, (void*) &nip);
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| 307 | pfx = " ";
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| 308 | dest += sprintf(dest, "/%u ", mask);
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| 309 | /* print router */
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| 310 | dest += sprint_nip(dest, "", option);
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| 311 | option += 4;
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| 312 | len -= 4;
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| 313 | }
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| 314 |
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| 315 | return ret;
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| 316 | }
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[3232] | 317 | case OPTION_6RD:
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| 318 | /* Option binary format (see RFC 5969):
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| 319 | * 0 1 2 3
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| 320 | * 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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| 321 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 322 | * | OPTION_6RD | option-length | IPv4MaskLen | 6rdPrefixLen |
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| 323 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 324 | * | 6rdPrefix |
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| 325 | * ... (16 octets) ...
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| 326 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 327 | * ... 6rdBRIPv4Address(es) ...
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| 328 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 329 | * We convert it to a string
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| 330 | * "IPv4MaskLen 6rdPrefixLen 6rdPrefix 6rdBRIPv4Address..."
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| 331 | *
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| 332 | * Sanity check: ensure that our length is at least 22 bytes, that
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| 333 | * IPv4MaskLen <= 32,
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| 334 | * 6rdPrefixLen <= 128,
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| 335 | * 6rdPrefixLen + (32 - IPv4MaskLen) <= 128
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| 336 | * (2nd condition need no check - it follows from 1st and 3rd).
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| 337 | * Else, return envvar with empty value ("optname=")
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| 338 | */
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| 339 | if (len >= (1 + 1 + 16 + 4)
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| 340 | && option[0] <= 32
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| 341 | && (option[1] + 32 - option[0]) <= 128
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| 342 | ) {
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| 343 | /* IPv4MaskLen */
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| 344 | dest += sprintf(dest, "%u ", *option++);
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| 345 | /* 6rdPrefixLen */
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| 346 | dest += sprintf(dest, "%u ", *option++);
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| 347 | /* 6rdPrefix */
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| 348 | dest += sprint_nip6(dest, /* "", */ option);
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| 349 | option += 16;
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| 350 | len -= 1 + 1 + 16 + 4;
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| 351 | /* "+ 4" above corresponds to the length of IPv4 addr
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| 352 | * we consume in the loop below */
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| 353 | while (1) {
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| 354 | /* 6rdBRIPv4Address(es) */
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| 355 | dest += sprint_nip(dest, " ", option);
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| 356 | option += 4;
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| 357 | len -= 4; /* do we have yet another 4+ bytes? */
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| 358 | if (len < 0)
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| 359 | break; /* no */
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| 360 | }
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| 361 | }
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| 362 |
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| 363 | return ret;
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[2725] | 364 | #if ENABLE_FEATURE_UDHCP_RFC3397
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| 365 | case OPTION_DNS_STRING:
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| 366 | /* unpack option into dest; use ret for prefix (i.e., "optname=") */
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| 367 | dest = dname_dec(option, len, ret);
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| 368 | if (dest) {
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| 369 | free(ret);
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| 370 | return dest;
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| 371 | }
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| 372 | /* error. return "optname=" string */
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| 373 | return ret;
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| 374 | case OPTION_SIP_SERVERS:
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| 375 | /* Option binary format:
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| 376 | * type: byte
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| 377 | * type=0: domain names, dns-compressed
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| 378 | * type=1: IP addrs
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| 379 | */
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| 380 | option++;
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| 381 | len--;
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| 382 | if (option[-1] == 0) {
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| 383 | dest = dname_dec(option, len, ret);
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| 384 | if (dest) {
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| 385 | free(ret);
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| 386 | return dest;
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| 387 | }
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| 388 | } else
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| 389 | if (option[-1] == 1) {
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| 390 | const char *pfx = "";
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| 391 | while (1) {
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| 392 | len -= 4;
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| 393 | if (len < 0)
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| 394 | break;
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| 395 | dest += sprint_nip(dest, pfx, option);
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| 396 | pfx = " ";
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| 397 | option += 4;
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| 398 | }
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| 399 | }
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| 400 | return ret;
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| 401 | #endif
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| 402 | } /* switch */
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[3232] | 403 |
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| 404 | /* If we are here, try to format any remaining data
|
---|
| 405 | * in the option as another, similarly-formatted option
|
---|
| 406 | */
|
---|
[2725] | 407 | option += optlen;
|
---|
| 408 | len -= optlen;
|
---|
| 409 | // TODO: it can be a list only if (optflag->flags & OPTION_LIST).
|
---|
| 410 | // Should we bail out/warn if we see multi-ip option which is
|
---|
| 411 | // not allowed to be such (for example, DHCP_BROADCAST)? -
|
---|
[3232] | 412 | if (len < optlen /* || !(optflag->flags & OPTION_LIST) */)
|
---|
[2725] | 413 | break;
|
---|
| 414 | *dest++ = ' ';
|
---|
| 415 | *dest = '\0';
|
---|
[3232] | 416 | } /* while */
|
---|
| 417 |
|
---|
[2725] | 418 | return ret;
|
---|
| 419 | }
|
---|
| 420 |
|
---|
| 421 | /* put all the parameters into the environment */
|
---|
| 422 | static char **fill_envp(struct dhcp_packet *packet)
|
---|
| 423 | {
|
---|
| 424 | int envc;
|
---|
| 425 | int i;
|
---|
| 426 | char **envp, **curr;
|
---|
| 427 | const char *opt_name;
|
---|
| 428 | uint8_t *temp;
|
---|
| 429 | uint8_t overload = 0;
|
---|
| 430 |
|
---|
[3232] | 431 | #define BITMAP unsigned
|
---|
| 432 | #define BBITS (sizeof(BITMAP) * 8)
|
---|
| 433 | #define BMASK(i) (1 << (i & (sizeof(BITMAP) * 8 - 1)))
|
---|
| 434 | #define FOUND_OPTS(i) (found_opts[(unsigned)i / BBITS])
|
---|
| 435 | BITMAP found_opts[256 / BBITS];
|
---|
| 436 |
|
---|
| 437 | memset(found_opts, 0, sizeof(found_opts));
|
---|
| 438 |
|
---|
[2725] | 439 | /* We need 6 elements for:
|
---|
| 440 | * "interface=IFACE"
|
---|
| 441 | * "ip=N.N.N.N" from packet->yiaddr
|
---|
| 442 | * "siaddr=IP" from packet->siaddr_nip (unless 0)
|
---|
| 443 | * "boot_file=FILE" from packet->file (unless overloaded)
|
---|
| 444 | * "sname=SERVER_HOSTNAME" from packet->sname (unless overloaded)
|
---|
| 445 | * terminating NULL
|
---|
| 446 | */
|
---|
| 447 | envc = 6;
|
---|
| 448 | /* +1 element for each option, +2 for subnet option: */
|
---|
| 449 | if (packet) {
|
---|
[3232] | 450 | /* note: do not search for "pad" (0) and "end" (255) options */
|
---|
| 451 | //TODO: change logic to scan packet _once_
|
---|
| 452 | for (i = 1; i < 255; i++) {
|
---|
| 453 | temp = udhcp_get_option(packet, i);
|
---|
| 454 | if (temp) {
|
---|
| 455 | if (i == DHCP_OPTION_OVERLOAD)
|
---|
| 456 | overload = *temp;
|
---|
| 457 | else if (i == DHCP_SUBNET)
|
---|
| 458 | envc++; /* for $mask */
|
---|
[2725] | 459 | envc++;
|
---|
[3232] | 460 | /*if (i != DHCP_MESSAGE_TYPE)*/
|
---|
| 461 | FOUND_OPTS(i) |= BMASK(i);
|
---|
[2725] | 462 | }
|
---|
| 463 | }
|
---|
| 464 | }
|
---|
[3232] | 465 | curr = envp = xzalloc(sizeof(envp[0]) * envc);
|
---|
[2725] | 466 |
|
---|
| 467 | *curr = xasprintf("interface=%s", client_config.interface);
|
---|
| 468 | putenv(*curr++);
|
---|
| 469 |
|
---|
| 470 | if (!packet)
|
---|
| 471 | return envp;
|
---|
| 472 |
|
---|
[3232] | 473 | /* Export BOOTP fields. Fields we don't (yet?) export:
|
---|
| 474 | * uint8_t op; // always BOOTREPLY
|
---|
| 475 | * uint8_t htype; // hardware address type. 1 = 10mb ethernet
|
---|
| 476 | * uint8_t hlen; // hardware address length
|
---|
| 477 | * uint8_t hops; // used by relay agents only
|
---|
| 478 | * uint32_t xid;
|
---|
| 479 | * uint16_t secs; // elapsed since client began acquisition/renewal
|
---|
| 480 | * uint16_t flags; // only one flag so far: bcast. Never set by server
|
---|
| 481 | * uint32_t ciaddr; // client IP (usually == yiaddr. can it be different
|
---|
| 482 | * // if during renew server wants to give us differn IP?)
|
---|
| 483 | * uint32_t gateway_nip; // relay agent IP address
|
---|
| 484 | * uint8_t chaddr[16]; // link-layer client hardware address (MAC)
|
---|
| 485 | * TODO: export gateway_nip as $giaddr?
|
---|
| 486 | */
|
---|
| 487 | /* Most important one: yiaddr as $ip */
|
---|
[2725] | 488 | *curr = xmalloc(sizeof("ip=255.255.255.255"));
|
---|
| 489 | sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr);
|
---|
| 490 | putenv(*curr++);
|
---|
[3232] | 491 | if (packet->siaddr_nip) {
|
---|
| 492 | /* IP address of next server to use in bootstrap */
|
---|
| 493 | *curr = xmalloc(sizeof("siaddr=255.255.255.255"));
|
---|
| 494 | sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip);
|
---|
| 495 | putenv(*curr++);
|
---|
| 496 | }
|
---|
| 497 | if (!(overload & FILE_FIELD) && packet->file[0]) {
|
---|
| 498 | /* watch out for invalid packets */
|
---|
| 499 | *curr = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file);
|
---|
| 500 | putenv(*curr++);
|
---|
| 501 | }
|
---|
| 502 | if (!(overload & SNAME_FIELD) && packet->sname[0]) {
|
---|
| 503 | /* watch out for invalid packets */
|
---|
| 504 | *curr = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname);
|
---|
| 505 | putenv(*curr++);
|
---|
| 506 | }
|
---|
[2725] | 507 |
|
---|
[3232] | 508 | /* Export known DHCP options */
|
---|
[2725] | 509 | opt_name = dhcp_option_strings;
|
---|
| 510 | i = 0;
|
---|
| 511 | while (*opt_name) {
|
---|
[3232] | 512 | uint8_t code = dhcp_optflags[i].code;
|
---|
| 513 | BITMAP *found_ptr = &FOUND_OPTS(code);
|
---|
| 514 | BITMAP found_mask = BMASK(code);
|
---|
| 515 | if (!(*found_ptr & found_mask))
|
---|
[2725] | 516 | goto next;
|
---|
[3232] | 517 | *found_ptr &= ~found_mask; /* leave only unknown options */
|
---|
| 518 | temp = udhcp_get_option(packet, code);
|
---|
[2725] | 519 | *curr = xmalloc_optname_optval(temp, &dhcp_optflags[i], opt_name);
|
---|
| 520 | putenv(*curr++);
|
---|
[3232] | 521 | if (code == DHCP_SUBNET) {
|
---|
[2725] | 522 | /* Subnet option: make things like "$ip/$mask" possible */
|
---|
| 523 | uint32_t subnet;
|
---|
| 524 | move_from_unaligned32(subnet, temp);
|
---|
[3232] | 525 | *curr = xasprintf("mask=%u", mton(subnet));
|
---|
[2725] | 526 | putenv(*curr++);
|
---|
| 527 | }
|
---|
| 528 | next:
|
---|
| 529 | opt_name += strlen(opt_name) + 1;
|
---|
| 530 | i++;
|
---|
| 531 | }
|
---|
[3232] | 532 | /* Export unknown options */
|
---|
| 533 | for (i = 0; i < 256;) {
|
---|
| 534 | BITMAP bitmap = FOUND_OPTS(i);
|
---|
| 535 | if (!bitmap) {
|
---|
| 536 | i += BBITS;
|
---|
| 537 | continue;
|
---|
| 538 | }
|
---|
| 539 | if (bitmap & BMASK(i)) {
|
---|
| 540 | unsigned len, ofs;
|
---|
| 541 |
|
---|
| 542 | temp = udhcp_get_option(packet, i);
|
---|
| 543 | /* udhcp_get_option returns ptr to data portion,
|
---|
| 544 | * need to go back to get len
|
---|
| 545 | */
|
---|
| 546 | len = temp[-OPT_DATA + OPT_LEN];
|
---|
| 547 | *curr = xmalloc(sizeof("optNNN=") + 1 + len*2);
|
---|
| 548 | ofs = sprintf(*curr, "opt%u=", i);
|
---|
| 549 | *bin2hex(*curr + ofs, (void*) temp, len) = '\0';
|
---|
| 550 | putenv(*curr++);
|
---|
| 551 | }
|
---|
| 552 | i++;
|
---|
[2725] | 553 | }
|
---|
[3232] | 554 |
|
---|
[2725] | 555 | return envp;
|
---|
| 556 | }
|
---|
| 557 |
|
---|
| 558 | /* Call a script with a par file and env vars */
|
---|
| 559 | static void udhcp_run_script(struct dhcp_packet *packet, const char *name)
|
---|
| 560 | {
|
---|
| 561 | char **envp, **curr;
|
---|
| 562 | char *argv[3];
|
---|
| 563 |
|
---|
| 564 | envp = fill_envp(packet);
|
---|
| 565 |
|
---|
| 566 | /* call script */
|
---|
[3621] | 567 | log1("executing %s %s", client_config.script, name);
|
---|
[2725] | 568 | argv[0] = (char*) client_config.script;
|
---|
| 569 | argv[1] = (char*) name;
|
---|
| 570 | argv[2] = NULL;
|
---|
| 571 | spawn_and_wait(argv);
|
---|
| 572 |
|
---|
| 573 | for (curr = envp; *curr; curr++) {
|
---|
| 574 | log2(" %s", *curr);
|
---|
| 575 | bb_unsetenv_and_free(*curr);
|
---|
| 576 | }
|
---|
| 577 | free(envp);
|
---|
| 578 | }
|
---|
| 579 |
|
---|
| 580 |
|
---|
| 581 | /*** Sending/receiving packets ***/
|
---|
| 582 |
|
---|
| 583 | static ALWAYS_INLINE uint32_t random_xid(void)
|
---|
| 584 | {
|
---|
| 585 | return rand();
|
---|
| 586 | }
|
---|
| 587 |
|
---|
| 588 | /* Initialize the packet with the proper defaults */
|
---|
| 589 | static void init_packet(struct dhcp_packet *packet, char type)
|
---|
| 590 | {
|
---|
[3232] | 591 | uint16_t secs;
|
---|
| 592 |
|
---|
[2725] | 593 | /* Fill in: op, htype, hlen, cookie fields; message type option: */
|
---|
| 594 | udhcp_init_header(packet, type);
|
---|
| 595 |
|
---|
| 596 | packet->xid = random_xid();
|
---|
| 597 |
|
---|
[3232] | 598 | client_config.last_secs = monotonic_sec();
|
---|
| 599 | if (client_config.first_secs == 0)
|
---|
| 600 | client_config.first_secs = client_config.last_secs;
|
---|
| 601 | secs = client_config.last_secs - client_config.first_secs;
|
---|
| 602 | packet->secs = htons(secs);
|
---|
| 603 |
|
---|
[2725] | 604 | memcpy(packet->chaddr, client_config.client_mac, 6);
|
---|
| 605 | if (client_config.clientid)
|
---|
| 606 | udhcp_add_binary_option(packet, client_config.clientid);
|
---|
| 607 | }
|
---|
| 608 |
|
---|
| 609 | static void add_client_options(struct dhcp_packet *packet)
|
---|
| 610 | {
|
---|
| 611 | int i, end, len;
|
---|
| 612 |
|
---|
| 613 | udhcp_add_simple_option(packet, DHCP_MAX_SIZE, htons(IP_UDP_DHCP_SIZE));
|
---|
| 614 |
|
---|
| 615 | /* Add a "param req" option with the list of options we'd like to have
|
---|
| 616 | * from stubborn DHCP servers. Pull the data from the struct in common.c.
|
---|
| 617 | * No bounds checking because it goes towards the head of the packet. */
|
---|
| 618 | end = udhcp_end_option(packet->options);
|
---|
| 619 | len = 0;
|
---|
[3232] | 620 | for (i = 1; i < DHCP_END; i++) {
|
---|
| 621 | if (client_config.opt_mask[i >> 3] & (1 << (i & 7))) {
|
---|
| 622 | packet->options[end + OPT_DATA + len] = i;
|
---|
[2725] | 623 | len++;
|
---|
| 624 | }
|
---|
| 625 | }
|
---|
| 626 | if (len) {
|
---|
| 627 | packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
|
---|
| 628 | packet->options[end + OPT_LEN] = len;
|
---|
| 629 | packet->options[end + OPT_DATA + len] = DHCP_END;
|
---|
| 630 | }
|
---|
| 631 |
|
---|
| 632 | if (client_config.vendorclass)
|
---|
| 633 | udhcp_add_binary_option(packet, client_config.vendorclass);
|
---|
| 634 | if (client_config.hostname)
|
---|
| 635 | udhcp_add_binary_option(packet, client_config.hostname);
|
---|
| 636 | if (client_config.fqdn)
|
---|
| 637 | udhcp_add_binary_option(packet, client_config.fqdn);
|
---|
| 638 |
|
---|
[3232] | 639 | /* Request broadcast replies if we have no IP addr */
|
---|
| 640 | if ((option_mask32 & OPT_B) && packet->ciaddr == 0)
|
---|
| 641 | packet->flags |= htons(BROADCAST_FLAG);
|
---|
| 642 |
|
---|
[2725] | 643 | /* Add -x options if any */
|
---|
| 644 | {
|
---|
| 645 | struct option_set *curr = client_config.options;
|
---|
| 646 | while (curr) {
|
---|
| 647 | udhcp_add_binary_option(packet, curr->data);
|
---|
| 648 | curr = curr->next;
|
---|
| 649 | }
|
---|
| 650 | // if (client_config.sname)
|
---|
| 651 | // strncpy((char*)packet->sname, client_config.sname, sizeof(packet->sname) - 1);
|
---|
| 652 | // if (client_config.boot_file)
|
---|
| 653 | // strncpy((char*)packet->file, client_config.boot_file, sizeof(packet->file) - 1);
|
---|
| 654 | }
|
---|
[3232] | 655 |
|
---|
| 656 | // This will be needed if we remove -V VENDOR_STR in favor of
|
---|
| 657 | // -x vendor:VENDOR_STR
|
---|
| 658 | //if (!udhcp_find_option(packet.options, DHCP_VENDOR))
|
---|
| 659 | // /* not set, set the default vendor ID */
|
---|
| 660 | // ...add (DHCP_VENDOR, "udhcp "BB_VER) opt...
|
---|
[2725] | 661 | }
|
---|
| 662 |
|
---|
| 663 | /* RFC 2131
|
---|
| 664 | * 4.4.4 Use of broadcast and unicast
|
---|
| 665 | *
|
---|
| 666 | * The DHCP client broadcasts DHCPDISCOVER, DHCPREQUEST and DHCPINFORM
|
---|
| 667 | * messages, unless the client knows the address of a DHCP server.
|
---|
| 668 | * The client unicasts DHCPRELEASE messages to the server. Because
|
---|
| 669 | * the client is declining the use of the IP address supplied by the server,
|
---|
| 670 | * the client broadcasts DHCPDECLINE messages.
|
---|
| 671 | *
|
---|
| 672 | * When the DHCP client knows the address of a DHCP server, in either
|
---|
| 673 | * INIT or REBOOTING state, the client may use that address
|
---|
| 674 | * in the DHCPDISCOVER or DHCPREQUEST rather than the IP broadcast address.
|
---|
| 675 | * The client may also use unicast to send DHCPINFORM messages
|
---|
| 676 | * to a known DHCP server. If the client receives no response to DHCP
|
---|
| 677 | * messages sent to the IP address of a known DHCP server, the DHCP
|
---|
| 678 | * client reverts to using the IP broadcast address.
|
---|
[1765] | 679 | */
|
---|
[2725] | 680 |
|
---|
[3621] | 681 | static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet, uint32_t src_nip)
|
---|
[2725] | 682 | {
|
---|
| 683 | return udhcp_send_raw_packet(packet,
|
---|
[3621] | 684 | /*src*/ src_nip, CLIENT_PORT,
|
---|
[2725] | 685 | /*dst*/ INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR,
|
---|
| 686 | client_config.ifindex);
|
---|
| 687 | }
|
---|
| 688 |
|
---|
[3621] | 689 | static int bcast_or_ucast(struct dhcp_packet *packet, uint32_t ciaddr, uint32_t server)
|
---|
| 690 | {
|
---|
| 691 | if (server)
|
---|
| 692 | return udhcp_send_kernel_packet(packet,
|
---|
| 693 | ciaddr, CLIENT_PORT,
|
---|
| 694 | server, SERVER_PORT);
|
---|
| 695 | return raw_bcast_from_client_config_ifindex(packet, ciaddr);
|
---|
| 696 | }
|
---|
| 697 |
|
---|
[2725] | 698 | /* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
|
---|
| 699 | /* NOINLINE: limit stack usage in caller */
|
---|
| 700 | static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
|
---|
| 701 | {
|
---|
| 702 | struct dhcp_packet packet;
|
---|
| 703 |
|
---|
| 704 | /* Fill in: op, htype, hlen, cookie, chaddr fields,
|
---|
| 705 | * random xid field (we override it below),
|
---|
| 706 | * client-id option (unless -C), message type option:
|
---|
| 707 | */
|
---|
| 708 | init_packet(&packet, DHCPDISCOVER);
|
---|
| 709 |
|
---|
| 710 | packet.xid = xid;
|
---|
| 711 | if (requested)
|
---|
| 712 | udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
|
---|
| 713 |
|
---|
| 714 | /* Add options: maxsize,
|
---|
| 715 | * optionally: hostname, fqdn, vendorclass,
|
---|
| 716 | * "param req" option according to -O, options specified with -x
|
---|
| 717 | */
|
---|
| 718 | add_client_options(&packet);
|
---|
| 719 |
|
---|
[3621] | 720 | bb_error_msg("sending %s", "discover");
|
---|
| 721 | return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
|
---|
[2725] | 722 | }
|
---|
| 723 |
|
---|
| 724 | /* Broadcast a DHCP request message */
|
---|
| 725 | /* RFC 2131 3.1 paragraph 3:
|
---|
| 726 | * "The client _broadcasts_ a DHCPREQUEST message..."
|
---|
| 727 | */
|
---|
| 728 | /* NOINLINE: limit stack usage in caller */
|
---|
| 729 | static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requested)
|
---|
| 730 | {
|
---|
| 731 | struct dhcp_packet packet;
|
---|
| 732 | struct in_addr addr;
|
---|
| 733 |
|
---|
| 734 | /*
|
---|
| 735 | * RFC 2131 4.3.2 DHCPREQUEST message
|
---|
| 736 | * ...
|
---|
| 737 | * If the DHCPREQUEST message contains a 'server identifier'
|
---|
| 738 | * option, the message is in response to a DHCPOFFER message.
|
---|
| 739 | * Otherwise, the message is a request to verify or extend an
|
---|
| 740 | * existing lease. If the client uses a 'client identifier'
|
---|
| 741 | * in a DHCPREQUEST message, it MUST use that same 'client identifier'
|
---|
| 742 | * in all subsequent messages. If the client included a list
|
---|
| 743 | * of requested parameters in a DHCPDISCOVER message, it MUST
|
---|
| 744 | * include that list in all subsequent messages.
|
---|
| 745 | */
|
---|
| 746 | /* Fill in: op, htype, hlen, cookie, chaddr fields,
|
---|
| 747 | * random xid field (we override it below),
|
---|
| 748 | * client-id option (unless -C), message type option:
|
---|
| 749 | */
|
---|
| 750 | init_packet(&packet, DHCPREQUEST);
|
---|
| 751 |
|
---|
| 752 | packet.xid = xid;
|
---|
| 753 | udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
|
---|
| 754 |
|
---|
| 755 | udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
|
---|
| 756 |
|
---|
| 757 | /* Add options: maxsize,
|
---|
| 758 | * optionally: hostname, fqdn, vendorclass,
|
---|
| 759 | * "param req" option according to -O, and options specified with -x
|
---|
| 760 | */
|
---|
| 761 | add_client_options(&packet);
|
---|
| 762 |
|
---|
| 763 | addr.s_addr = requested;
|
---|
[3621] | 764 | bb_error_msg("sending select for %s", inet_ntoa(addr));
|
---|
| 765 | return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
|
---|
[2725] | 766 | }
|
---|
| 767 |
|
---|
| 768 | /* Unicast or broadcast a DHCP renew message */
|
---|
| 769 | /* NOINLINE: limit stack usage in caller */
|
---|
| 770 | static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
|
---|
| 771 | {
|
---|
| 772 | struct dhcp_packet packet;
|
---|
| 773 |
|
---|
| 774 | /*
|
---|
| 775 | * RFC 2131 4.3.2 DHCPREQUEST message
|
---|
| 776 | * ...
|
---|
| 777 | * DHCPREQUEST generated during RENEWING state:
|
---|
| 778 | *
|
---|
| 779 | * 'server identifier' MUST NOT be filled in, 'requested IP address'
|
---|
| 780 | * option MUST NOT be filled in, 'ciaddr' MUST be filled in with
|
---|
| 781 | * client's IP address. In this situation, the client is completely
|
---|
| 782 | * configured, and is trying to extend its lease. This message will
|
---|
| 783 | * be unicast, so no relay agents will be involved in its
|
---|
| 784 | * transmission. Because 'giaddr' is therefore not filled in, the
|
---|
| 785 | * DHCP server will trust the value in 'ciaddr', and use it when
|
---|
| 786 | * replying to the client.
|
---|
| 787 | */
|
---|
| 788 | /* Fill in: op, htype, hlen, cookie, chaddr fields,
|
---|
| 789 | * random xid field (we override it below),
|
---|
| 790 | * client-id option (unless -C), message type option:
|
---|
| 791 | */
|
---|
| 792 | init_packet(&packet, DHCPREQUEST);
|
---|
| 793 |
|
---|
| 794 | packet.xid = xid;
|
---|
| 795 | packet.ciaddr = ciaddr;
|
---|
| 796 |
|
---|
| 797 | /* Add options: maxsize,
|
---|
| 798 | * optionally: hostname, fqdn, vendorclass,
|
---|
| 799 | * "param req" option according to -O, and options specified with -x
|
---|
| 800 | */
|
---|
| 801 | add_client_options(&packet);
|
---|
| 802 |
|
---|
[3621] | 803 | bb_error_msg("sending %s", "renew");
|
---|
| 804 | return bcast_or_ucast(&packet, ciaddr, server);
|
---|
[2725] | 805 | }
|
---|
| 806 |
|
---|
| 807 | #if ENABLE_FEATURE_UDHCPC_ARPING
|
---|
| 808 | /* Broadcast a DHCP decline message */
|
---|
| 809 | /* NOINLINE: limit stack usage in caller */
|
---|
[3232] | 810 | static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t requested)
|
---|
[2725] | 811 | {
|
---|
| 812 | struct dhcp_packet packet;
|
---|
| 813 |
|
---|
| 814 | /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
|
---|
| 815 | * client-id option (unless -C), message type option:
|
---|
| 816 | */
|
---|
| 817 | init_packet(&packet, DHCPDECLINE);
|
---|
| 818 |
|
---|
[3232] | 819 | #if 0
|
---|
[2725] | 820 | /* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
|
---|
| 821 | * but in case the server is buggy and wants DHCPDECLINE's xid
|
---|
| 822 | * to match the xid which started entire handshake,
|
---|
| 823 | * we use the same xid we used in initial DHCPDISCOVER:
|
---|
| 824 | */
|
---|
| 825 | packet.xid = xid;
|
---|
[3232] | 826 | #endif
|
---|
[2725] | 827 | /* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
|
---|
| 828 | udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
|
---|
| 829 |
|
---|
| 830 | udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
|
---|
| 831 |
|
---|
[3621] | 832 | bb_error_msg("sending %s", "decline");
|
---|
| 833 | return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
|
---|
[2725] | 834 | }
|
---|
| 835 | #endif
|
---|
| 836 |
|
---|
| 837 | /* Unicast a DHCP release message */
|
---|
| 838 | static int send_release(uint32_t server, uint32_t ciaddr)
|
---|
| 839 | {
|
---|
| 840 | struct dhcp_packet packet;
|
---|
| 841 |
|
---|
| 842 | /* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
|
---|
| 843 | * client-id option (unless -C), message type option:
|
---|
| 844 | */
|
---|
| 845 | init_packet(&packet, DHCPRELEASE);
|
---|
| 846 |
|
---|
| 847 | /* DHCPRELEASE uses ciaddr, not "requested ip", to store IP being released */
|
---|
| 848 | packet.ciaddr = ciaddr;
|
---|
| 849 |
|
---|
| 850 | udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
|
---|
| 851 |
|
---|
[3621] | 852 | bb_error_msg("sending %s", "release");
|
---|
| 853 | /* Note: normally we unicast here since "server" is not zero.
|
---|
| 854 | * However, there _are_ people who run "address-less" DHCP servers,
|
---|
| 855 | * and reportedly ISC dhcp client and Windows allow that.
|
---|
| 856 | */
|
---|
| 857 | return bcast_or_ucast(&packet, ciaddr, server);
|
---|
[2725] | 858 | }
|
---|
| 859 |
|
---|
| 860 | /* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */
|
---|
| 861 | /* NOINLINE: limit stack usage in caller */
|
---|
| 862 | static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
|
---|
| 863 | {
|
---|
| 864 | int bytes;
|
---|
| 865 | struct ip_udp_dhcp_packet packet;
|
---|
| 866 | uint16_t check;
|
---|
[3232] | 867 | unsigned char cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
|
---|
| 868 | struct iovec iov;
|
---|
| 869 | struct msghdr msg;
|
---|
[3621] | 870 | struct cmsghdr *cmsg;
|
---|
[2725] | 871 |
|
---|
[3232] | 872 | /* used to use just safe_read(fd, &packet, sizeof(packet))
|
---|
| 873 | * but we need to check for TP_STATUS_CSUMNOTREADY :(
|
---|
| 874 | */
|
---|
| 875 | iov.iov_base = &packet;
|
---|
| 876 | iov.iov_len = sizeof(packet);
|
---|
| 877 | memset(&msg, 0, sizeof(msg));
|
---|
| 878 | msg.msg_iov = &iov;
|
---|
| 879 | msg.msg_iovlen = 1;
|
---|
| 880 | msg.msg_control = cmsgbuf;
|
---|
| 881 | msg.msg_controllen = sizeof(cmsgbuf);
|
---|
| 882 | for (;;) {
|
---|
| 883 | bytes = recvmsg(fd, &msg, 0);
|
---|
| 884 | if (bytes < 0) {
|
---|
| 885 | if (errno == EINTR)
|
---|
| 886 | continue;
|
---|
[3621] | 887 | log1("packet read error, ignoring");
|
---|
[3232] | 888 | /* NB: possible down interface, etc. Caller should pause. */
|
---|
| 889 | return bytes; /* returns -1 */
|
---|
| 890 | }
|
---|
| 891 | break;
|
---|
[2725] | 892 | }
|
---|
| 893 |
|
---|
| 894 | if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) {
|
---|
[3621] | 895 | log1("packet is too short, ignoring");
|
---|
[2725] | 896 | return -2;
|
---|
| 897 | }
|
---|
| 898 |
|
---|
| 899 | if (bytes < ntohs(packet.ip.tot_len)) {
|
---|
| 900 | /* packet is bigger than sizeof(packet), we did partial read */
|
---|
[3621] | 901 | log1("oversized packet, ignoring");
|
---|
[2725] | 902 | return -2;
|
---|
| 903 | }
|
---|
| 904 |
|
---|
| 905 | /* ignore any extra garbage bytes */
|
---|
| 906 | bytes = ntohs(packet.ip.tot_len);
|
---|
| 907 |
|
---|
| 908 | /* make sure its the right packet for us, and that it passes sanity checks */
|
---|
[3232] | 909 | if (packet.ip.protocol != IPPROTO_UDP
|
---|
| 910 | || packet.ip.version != IPVERSION
|
---|
[2725] | 911 | || packet.ip.ihl != (sizeof(packet.ip) >> 2)
|
---|
| 912 | || packet.udp.dest != htons(CLIENT_PORT)
|
---|
| 913 | /* || bytes > (int) sizeof(packet) - can't happen */
|
---|
| 914 | || ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip))
|
---|
| 915 | ) {
|
---|
[3621] | 916 | log1("unrelated/bogus packet, ignoring");
|
---|
[2725] | 917 | return -2;
|
---|
| 918 | }
|
---|
| 919 |
|
---|
| 920 | /* verify IP checksum */
|
---|
| 921 | check = packet.ip.check;
|
---|
| 922 | packet.ip.check = 0;
|
---|
[3232] | 923 | if (check != inet_cksum((uint16_t *)&packet.ip, sizeof(packet.ip))) {
|
---|
[3621] | 924 | log1("bad IP header checksum, ignoring");
|
---|
[2725] | 925 | return -2;
|
---|
| 926 | }
|
---|
| 927 |
|
---|
[3232] | 928 | for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
|
---|
| 929 | if (cmsg->cmsg_level == SOL_PACKET
|
---|
| 930 | && cmsg->cmsg_type == PACKET_AUXDATA
|
---|
| 931 | ) {
|
---|
| 932 | /* some VMs don't checksum UDP and TCP data
|
---|
| 933 | * they send to the same physical machine,
|
---|
| 934 | * here we detect this case:
|
---|
| 935 | */
|
---|
| 936 | struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
|
---|
| 937 | if (aux->tp_status & TP_STATUS_CSUMNOTREADY)
|
---|
| 938 | goto skip_udp_sum_check;
|
---|
| 939 | }
|
---|
| 940 | }
|
---|
| 941 |
|
---|
[2725] | 942 | /* verify UDP checksum. IP header has to be modified for this */
|
---|
| 943 | memset(&packet.ip, 0, offsetof(struct iphdr, protocol));
|
---|
| 944 | /* ip.xx fields which are not memset: protocol, check, saddr, daddr */
|
---|
| 945 | packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
|
---|
| 946 | check = packet.udp.check;
|
---|
| 947 | packet.udp.check = 0;
|
---|
[3232] | 948 | if (check && check != inet_cksum((uint16_t *)&packet, bytes)) {
|
---|
[3621] | 949 | log1("packet with bad UDP checksum received, ignoring");
|
---|
[2725] | 950 | return -2;
|
---|
| 951 | }
|
---|
[3232] | 952 | skip_udp_sum_check:
|
---|
[2725] | 953 |
|
---|
[3232] | 954 | if (packet.data.cookie != htonl(DHCP_MAGIC)) {
|
---|
[3621] | 955 | bb_error_msg("packet with bad magic, ignoring");
|
---|
[2725] | 956 | return -2;
|
---|
| 957 | }
|
---|
[3232] | 958 |
|
---|
[3621] | 959 | log1("received %s", "a packet");
|
---|
[3232] | 960 | udhcp_dump_packet(&packet.data);
|
---|
| 961 |
|
---|
| 962 | bytes -= sizeof(packet.ip) + sizeof(packet.udp);
|
---|
| 963 | memcpy(dhcp_pkt, &packet.data, bytes);
|
---|
| 964 | return bytes;
|
---|
[2725] | 965 | }
|
---|
| 966 |
|
---|
| 967 |
|
---|
| 968 | /*** Main ***/
|
---|
| 969 |
|
---|
[1765] | 970 | static int sockfd = -1;
|
---|
[821] | 971 |
|
---|
[2725] | 972 | #define LISTEN_NONE 0
|
---|
[821] | 973 | #define LISTEN_KERNEL 1
|
---|
[2725] | 974 | #define LISTEN_RAW 2
|
---|
[1765] | 975 | static smallint listen_mode;
|
---|
[821] | 976 |
|
---|
[2725] | 977 | /* initial state: (re)start DHCP negotiation */
|
---|
| 978 | #define INIT_SELECTING 0
|
---|
| 979 | /* discover was sent, DHCPOFFER reply received */
|
---|
| 980 | #define REQUESTING 1
|
---|
| 981 | /* select/renew was sent, DHCPACK reply received */
|
---|
| 982 | #define BOUND 2
|
---|
| 983 | /* half of lease passed, want to renew it by sending unicast renew requests */
|
---|
| 984 | #define RENEWING 3
|
---|
| 985 | /* renew requests were not answered, lease is almost over, send broadcast renew */
|
---|
| 986 | #define REBINDING 4
|
---|
| 987 | /* manually requested renew (SIGUSR1) */
|
---|
| 988 | #define RENEW_REQUESTED 5
|
---|
| 989 | /* release, possibly manually requested (SIGUSR2) */
|
---|
| 990 | #define RELEASED 6
|
---|
[1765] | 991 | static smallint state;
|
---|
[821] | 992 |
|
---|
[2725] | 993 | static int udhcp_raw_socket(int ifindex)
|
---|
| 994 | {
|
---|
| 995 | int fd;
|
---|
| 996 | struct sockaddr_ll sock;
|
---|
[1765] | 997 |
|
---|
[3621] | 998 | log1("opening raw socket on ifindex %d", ifindex); //log2?
|
---|
[1765] | 999 |
|
---|
[2725] | 1000 | fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
|
---|
[3621] | 1001 | /* ^^^^^
|
---|
| 1002 | * SOCK_DGRAM: remove link-layer headers on input (SOCK_RAW keeps them)
|
---|
| 1003 | * ETH_P_IP: want to receive only packets with IPv4 eth type
|
---|
| 1004 | */
|
---|
| 1005 | log1("got raw socket fd"); //log2?
|
---|
[2725] | 1006 |
|
---|
[3232] | 1007 | sock.sll_family = AF_PACKET;
|
---|
| 1008 | sock.sll_protocol = htons(ETH_P_IP);
|
---|
| 1009 | sock.sll_ifindex = ifindex;
|
---|
| 1010 | xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
|
---|
| 1011 |
|
---|
[3621] | 1012 | #if 0 /* Several users reported breakage when BPF filter is used */
|
---|
[3232] | 1013 | if (CLIENT_PORT == 68) {
|
---|
| 1014 | /* Use only if standard port is in use */
|
---|
[3621] | 1015 | /*
|
---|
| 1016 | * I've selected not to see LL header, so BPF doesn't see it, too.
|
---|
| 1017 | * The filter may also pass non-IP and non-ARP packets, but we do
|
---|
| 1018 | * a more complete check when receiving the message in userspace.
|
---|
| 1019 | *
|
---|
| 1020 | * and filter shamelessly stolen from:
|
---|
| 1021 | *
|
---|
| 1022 | * http://www.flamewarmaster.de/software/dhcpclient/
|
---|
| 1023 | *
|
---|
| 1024 | * There are a few other interesting ideas on that page (look under
|
---|
| 1025 | * "Motivation"). Use of netlink events is most interesting. Think
|
---|
| 1026 | * of various network servers listening for events and reconfiguring.
|
---|
| 1027 | * That would obsolete sending HUP signals and/or make use of restarts.
|
---|
| 1028 | *
|
---|
| 1029 | * Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
|
---|
| 1030 | * License: GPL v2.
|
---|
| 1031 | */
|
---|
| 1032 | static const struct sock_filter filter_instr[] = {
|
---|
| 1033 | /* load 9th byte (protocol) */
|
---|
| 1034 | BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
|
---|
| 1035 | /* jump to L1 if it is IPPROTO_UDP, else to L4 */
|
---|
| 1036 | BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 0, 6),
|
---|
| 1037 | /* L1: load halfword from offset 6 (flags and frag offset) */
|
---|
| 1038 | BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 6),
|
---|
| 1039 | /* jump to L4 if any bits in frag offset field are set, else to L2 */
|
---|
| 1040 | BPF_JUMP(BPF_JMP|BPF_JSET|BPF_K, 0x1fff, 4, 0),
|
---|
| 1041 | /* L2: skip IP header (load index reg with header len) */
|
---|
| 1042 | BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0),
|
---|
| 1043 | /* load udp destination port from halfword[header_len + 2] */
|
---|
| 1044 | BPF_STMT(BPF_LD|BPF_H|BPF_IND, 2),
|
---|
| 1045 | /* jump to L3 if udp dport is CLIENT_PORT, else to L4 */
|
---|
| 1046 | BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
|
---|
| 1047 | /* L3: accept packet ("accept 0x7fffffff bytes") */
|
---|
| 1048 | /* Accepting 0xffffffff works too but kernel 2.6.19 is buggy */
|
---|
| 1049 | BPF_STMT(BPF_RET|BPF_K, 0x7fffffff),
|
---|
| 1050 | /* L4: discard packet ("accept zero bytes") */
|
---|
| 1051 | BPF_STMT(BPF_RET|BPF_K, 0),
|
---|
| 1052 | };
|
---|
| 1053 | static const struct sock_fprog filter_prog = {
|
---|
| 1054 | .len = sizeof(filter_instr) / sizeof(filter_instr[0]),
|
---|
| 1055 | /* casting const away: */
|
---|
| 1056 | .filter = (struct sock_filter *) filter_instr,
|
---|
| 1057 | };
|
---|
[2725] | 1058 | /* Ignoring error (kernel may lack support for this) */
|
---|
| 1059 | if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
|
---|
| 1060 | sizeof(filter_prog)) >= 0)
|
---|
[3621] | 1061 | log1("attached filter to raw socket fd"); // log?
|
---|
[2725] | 1062 | }
|
---|
[3621] | 1063 | #endif
|
---|
[2725] | 1064 |
|
---|
[3621] | 1065 | if (setsockopt_1(fd, SOL_PACKET, PACKET_AUXDATA) != 0) {
|
---|
[3232] | 1066 | if (errno != ENOPROTOOPT)
|
---|
[3621] | 1067 | log1("can't set PACKET_AUXDATA on raw socket");
|
---|
[3232] | 1068 | }
|
---|
| 1069 |
|
---|
[3621] | 1070 | log1("created raw socket");
|
---|
[2725] | 1071 |
|
---|
| 1072 | return fd;
|
---|
| 1073 | }
|
---|
| 1074 |
|
---|
| 1075 | static void change_listen_mode(int new_mode)
|
---|
[821] | 1076 | {
|
---|
[3621] | 1077 | log1("entering listen mode: %s",
|
---|
[2725] | 1078 | new_mode != LISTEN_NONE
|
---|
| 1079 | ? (new_mode == LISTEN_KERNEL ? "kernel" : "raw")
|
---|
| 1080 | : "none"
|
---|
| 1081 | );
|
---|
| 1082 |
|
---|
| 1083 | listen_mode = new_mode;
|
---|
[1765] | 1084 | if (sockfd >= 0) {
|
---|
| 1085 | close(sockfd);
|
---|
| 1086 | sockfd = -1;
|
---|
| 1087 | }
|
---|
[2725] | 1088 | if (new_mode == LISTEN_KERNEL)
|
---|
| 1089 | sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
|
---|
| 1090 | else if (new_mode != LISTEN_NONE)
|
---|
| 1091 | sockfd = udhcp_raw_socket(client_config.ifindex);
|
---|
| 1092 | /* else LISTEN_NONE: sockfd stays closed */
|
---|
[821] | 1093 | }
|
---|
| 1094 |
|
---|
[3232] | 1095 | /* Called only on SIGUSR1 */
|
---|
[821] | 1096 | static void perform_renew(void)
|
---|
| 1097 | {
|
---|
[3621] | 1098 | bb_error_msg("performing DHCP renew");
|
---|
[821] | 1099 | switch (state) {
|
---|
| 1100 | case BOUND:
|
---|
[2725] | 1101 | change_listen_mode(LISTEN_KERNEL);
|
---|
[821] | 1102 | case RENEWING:
|
---|
| 1103 | case REBINDING:
|
---|
| 1104 | state = RENEW_REQUESTED;
|
---|
| 1105 | break;
|
---|
| 1106 | case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
|
---|
| 1107 | udhcp_run_script(NULL, "deconfig");
|
---|
| 1108 | case REQUESTING:
|
---|
| 1109 | case RELEASED:
|
---|
[2725] | 1110 | change_listen_mode(LISTEN_RAW);
|
---|
[821] | 1111 | state = INIT_SELECTING;
|
---|
| 1112 | break;
|
---|
| 1113 | case INIT_SELECTING:
|
---|
| 1114 | break;
|
---|
| 1115 | }
|
---|
| 1116 | }
|
---|
| 1117 |
|
---|
[3232] | 1118 | static void perform_release(uint32_t server_addr, uint32_t requested_ip)
|
---|
[821] | 1119 | {
|
---|
[1765] | 1120 | char buffer[sizeof("255.255.255.255")];
|
---|
[821] | 1121 | struct in_addr temp_addr;
|
---|
| 1122 |
|
---|
| 1123 | /* send release packet */
|
---|
| 1124 | if (state == BOUND || state == RENEWING || state == REBINDING) {
|
---|
| 1125 | temp_addr.s_addr = server_addr;
|
---|
[1765] | 1126 | strcpy(buffer, inet_ntoa(temp_addr));
|
---|
[821] | 1127 | temp_addr.s_addr = requested_ip;
|
---|
[3621] | 1128 | bb_error_msg("unicasting a release of %s to %s",
|
---|
[821] | 1129 | inet_ntoa(temp_addr), buffer);
|
---|
| 1130 | send_release(server_addr, requested_ip); /* unicast */
|
---|
| 1131 | udhcp_run_script(NULL, "deconfig");
|
---|
| 1132 | }
|
---|
[3621] | 1133 | bb_error_msg("entering released state");
|
---|
[821] | 1134 |
|
---|
[2725] | 1135 | change_listen_mode(LISTEN_NONE);
|
---|
[821] | 1136 | state = RELEASED;
|
---|
| 1137 | }
|
---|
| 1138 |
|
---|
[1765] | 1139 | static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
|
---|
[821] | 1140 | {
|
---|
[1765] | 1141 | uint8_t *storage;
|
---|
[2725] | 1142 | int len = strnlen(str, 255);
|
---|
[1765] | 1143 | storage = xzalloc(len + extra + OPT_DATA);
|
---|
| 1144 | storage[OPT_CODE] = code;
|
---|
| 1145 | storage[OPT_LEN] = len + extra;
|
---|
| 1146 | memcpy(storage + extra + OPT_DATA, str, len);
|
---|
| 1147 | return storage;
|
---|
| 1148 | }
|
---|
| 1149 |
|
---|
[2725] | 1150 | #if BB_MMU
|
---|
| 1151 | static void client_background(void)
|
---|
| 1152 | {
|
---|
| 1153 | bb_daemonize(0);
|
---|
| 1154 | logmode &= ~LOGMODE_STDIO;
|
---|
| 1155 | /* rewrite pidfile, as our pid is different now */
|
---|
| 1156 | write_pidfile(client_config.pidfile);
|
---|
| 1157 | }
|
---|
| 1158 | #endif
|
---|
[1765] | 1159 |
|
---|
[2725] | 1160 | //usage:#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
|
---|
| 1161 | //usage:# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
|
---|
| 1162 | //usage:#else
|
---|
| 1163 | //usage:# define IF_UDHCP_VERBOSE(...)
|
---|
| 1164 | //usage:#endif
|
---|
| 1165 | //usage:#define udhcpc_trivial_usage
|
---|
[3621] | 1166 | //usage: "[-fbq"IF_UDHCP_VERBOSE("v")"RB]"IF_FEATURE_UDHCPC_ARPING(" [-a[MSEC]]")" [-t N] [-T SEC] [-A SEC/-n]\n"
|
---|
| 1167 | //usage: " [-i IFACE]"IF_FEATURE_UDHCP_PORT(" [-P PORT]")" [-s PROG] [-p PIDFILE]\n"
|
---|
| 1168 | //usage: " [-oC] [-r IP] [-V VENDOR] [-F NAME] [-x OPT:VAL]... [-O OPT]..."
|
---|
[2725] | 1169 | //usage:#define udhcpc_full_usage "\n"
|
---|
| 1170 | //usage: IF_LONG_OPTS(
|
---|
| 1171 | //usage: "\n -i,--interface IFACE Interface to use (default eth0)"
|
---|
[3621] | 1172 | //usage: IF_FEATURE_UDHCP_PORT(
|
---|
| 1173 | //usage: "\n -P,--client-port PORT Use PORT (default 68)"
|
---|
| 1174 | //usage: )
|
---|
| 1175 | //usage: "\n -s,--script PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
|
---|
[2725] | 1176 | //usage: "\n -p,--pidfile FILE Create pidfile"
|
---|
[3232] | 1177 | //usage: "\n -B,--broadcast Request broadcast replies"
|
---|
[3621] | 1178 | //usage: "\n -t,--retries N Send up to N discover packets (default 3)"
|
---|
| 1179 | //usage: "\n -T,--timeout SEC Pause between packets (default 3)"
|
---|
| 1180 | //usage: "\n -A,--tryagain SEC Wait if lease is not obtained (default 20)"
|
---|
| 1181 | //usage: "\n -n,--now Exit if lease is not obtained"
|
---|
| 1182 | //usage: "\n -q,--quit Exit after obtaining lease"
|
---|
| 1183 | //usage: "\n -R,--release Release IP on exit"
|
---|
[2725] | 1184 | //usage: "\n -f,--foreground Run in foreground"
|
---|
| 1185 | //usage: USE_FOR_MMU(
|
---|
| 1186 | //usage: "\n -b,--background Background if lease is not obtained"
|
---|
| 1187 | //usage: )
|
---|
| 1188 | //usage: "\n -S,--syslog Log to syslog too"
|
---|
| 1189 | //usage: IF_FEATURE_UDHCPC_ARPING(
|
---|
[3621] | 1190 | //usage: "\n -a[MSEC],--arping[=MSEC] Validate offered address with ARP ping"
|
---|
[2725] | 1191 | //usage: )
|
---|
[3621] | 1192 | //usage: "\n -r,--request IP Request this IP address"
|
---|
| 1193 | //usage: "\n -o,--no-default-options Don't request any options (unless -O is given)"
|
---|
[2725] | 1194 | //usage: "\n -O,--request-option OPT Request option OPT from server (cumulative)"
|
---|
| 1195 | //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
|
---|
| 1196 | //usage: "\n Examples of string, numeric, and hex byte opts:"
|
---|
| 1197 | //usage: "\n -x hostname:bbox - option 12"
|
---|
| 1198 | //usage: "\n -x lease:3600 - option 51 (lease time)"
|
---|
| 1199 | //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
|
---|
| 1200 | //usage: "\n -F,--fqdn NAME Ask server to update DNS mapping for NAME"
|
---|
| 1201 | //usage: "\n -V,--vendorclass VENDOR Vendor identifier (default 'udhcp VERSION')"
|
---|
| 1202 | //usage: "\n -C,--clientid-none Don't send MAC as client identifier"
|
---|
| 1203 | //usage: IF_UDHCP_VERBOSE(
|
---|
| 1204 | //usage: "\n -v Verbose"
|
---|
| 1205 | //usage: )
|
---|
| 1206 | //usage: )
|
---|
| 1207 | //usage: IF_NOT_LONG_OPTS(
|
---|
| 1208 | //usage: "\n -i IFACE Interface to use (default eth0)"
|
---|
[3621] | 1209 | //usage: IF_FEATURE_UDHCP_PORT(
|
---|
| 1210 | //usage: "\n -P PORT Use PORT (default 68)"
|
---|
| 1211 | //usage: )
|
---|
| 1212 | //usage: "\n -s PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
|
---|
[2725] | 1213 | //usage: "\n -p FILE Create pidfile"
|
---|
[3232] | 1214 | //usage: "\n -B Request broadcast replies"
|
---|
[3621] | 1215 | //usage: "\n -t N Send up to N discover packets (default 3)"
|
---|
| 1216 | //usage: "\n -T SEC Pause between packets (default 3)"
|
---|
| 1217 | //usage: "\n -A SEC Wait if lease is not obtained (default 20)"
|
---|
| 1218 | //usage: "\n -n Exit if lease is not obtained"
|
---|
| 1219 | //usage: "\n -q Exit after obtaining lease"
|
---|
| 1220 | //usage: "\n -R Release IP on exit"
|
---|
[2725] | 1221 | //usage: "\n -f Run in foreground"
|
---|
| 1222 | //usage: USE_FOR_MMU(
|
---|
| 1223 | //usage: "\n -b Background if lease is not obtained"
|
---|
| 1224 | //usage: )
|
---|
| 1225 | //usage: "\n -S Log to syslog too"
|
---|
| 1226 | //usage: IF_FEATURE_UDHCPC_ARPING(
|
---|
[3621] | 1227 | //usage: "\n -a[MSEC] Validate offered address with ARP ping"
|
---|
[2725] | 1228 | //usage: )
|
---|
[3621] | 1229 | //usage: "\n -r IP Request this IP address"
|
---|
| 1230 | //usage: "\n -o Don't request any options (unless -O is given)"
|
---|
[2725] | 1231 | //usage: "\n -O OPT Request option OPT from server (cumulative)"
|
---|
| 1232 | //usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
|
---|
| 1233 | //usage: "\n Examples of string, numeric, and hex byte opts:"
|
---|
| 1234 | //usage: "\n -x hostname:bbox - option 12"
|
---|
| 1235 | //usage: "\n -x lease:3600 - option 51 (lease time)"
|
---|
| 1236 | //usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
|
---|
| 1237 | //usage: "\n -F NAME Ask server to update DNS mapping for NAME"
|
---|
| 1238 | //usage: "\n -V VENDOR Vendor identifier (default 'udhcp VERSION')"
|
---|
| 1239 | //usage: "\n -C Don't send MAC as client identifier"
|
---|
| 1240 | //usage: IF_UDHCP_VERBOSE(
|
---|
| 1241 | //usage: "\n -v Verbose"
|
---|
| 1242 | //usage: )
|
---|
| 1243 | //usage: )
|
---|
[3232] | 1244 | //usage: "\nSignals:"
|
---|
| 1245 | //usage: "\n USR1 Renew lease"
|
---|
| 1246 | //usage: "\n USR2 Release lease"
|
---|
[2725] | 1247 |
|
---|
[3232] | 1248 |
|
---|
[2725] | 1249 | int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
---|
| 1250 | int udhcpc_main(int argc UNUSED_PARAM, char **argv)
|
---|
[1765] | 1251 | {
|
---|
[3621] | 1252 | uint8_t *message;
|
---|
[2725] | 1253 | const char *str_V, *str_h, *str_F, *str_r;
|
---|
[3621] | 1254 | IF_FEATURE_UDHCPC_ARPING(const char *str_a = "2000";)
|
---|
[2725] | 1255 | IF_FEATURE_UDHCP_PORT(char *str_P;)
|
---|
| 1256 | void *clientid_mac_ptr;
|
---|
| 1257 | llist_t *list_O = NULL;
|
---|
| 1258 | llist_t *list_x = NULL;
|
---|
| 1259 | int tryagain_timeout = 20;
|
---|
| 1260 | int discover_timeout = 3;
|
---|
| 1261 | int discover_retries = 3;
|
---|
| 1262 | uint32_t server_addr = server_addr; /* for compiler */
|
---|
| 1263 | uint32_t requested_ip = 0;
|
---|
[3232] | 1264 | uint32_t xid = xid; /* for compiler */
|
---|
[2725] | 1265 | int packet_num;
|
---|
| 1266 | int timeout; /* must be signed */
|
---|
| 1267 | unsigned already_waited_sec;
|
---|
[1765] | 1268 | unsigned opt;
|
---|
[3621] | 1269 | IF_FEATURE_UDHCPC_ARPING(unsigned arpping_ms;)
|
---|
[1765] | 1270 | int max_fd;
|
---|
[821] | 1271 | int retval;
|
---|
[1765] | 1272 | fd_set rfds;
|
---|
[821] | 1273 |
|
---|
[3621] | 1274 | setup_common_bufsiz();
|
---|
| 1275 |
|
---|
[2725] | 1276 | /* Default options */
|
---|
| 1277 | IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
|
---|
| 1278 | IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
|
---|
[1765] | 1279 | client_config.interface = "eth0";
|
---|
[2725] | 1280 | client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
|
---|
| 1281 | str_V = "udhcp "BB_VER;
|
---|
[821] | 1282 |
|
---|
[1765] | 1283 | /* Parse command line */
|
---|
[2725] | 1284 | /* O,x: list; -T,-t,-A take numeric param */
|
---|
[3232] | 1285 | opt_complementary = "O::x::T+:t+:A+" IF_UDHCP_VERBOSE(":vv") ;
|
---|
[2725] | 1286 | IF_LONG_OPTS(applet_long_options = udhcpc_longopts;)
|
---|
[3232] | 1287 | opt = getopt32(argv, "CV:H:h:F:i:np:qRr:s:T:t:SA:O:ox:fB"
|
---|
[2725] | 1288 | USE_FOR_MMU("b")
|
---|
[3621] | 1289 | IF_FEATURE_UDHCPC_ARPING("a::")
|
---|
[2725] | 1290 | IF_FEATURE_UDHCP_PORT("P:")
|
---|
| 1291 | "v"
|
---|
| 1292 | , &str_V, &str_h, &str_h, &str_F
|
---|
| 1293 | , &client_config.interface, &client_config.pidfile, &str_r /* i,p */
|
---|
| 1294 | , &client_config.script /* s */
|
---|
| 1295 | , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
|
---|
| 1296 | , &list_O
|
---|
| 1297 | , &list_x
|
---|
[3621] | 1298 | IF_FEATURE_UDHCPC_ARPING(, &str_a)
|
---|
[2725] | 1299 | IF_FEATURE_UDHCP_PORT(, &str_P)
|
---|
[3232] | 1300 | IF_UDHCP_VERBOSE(, &dhcp_verbose)
|
---|
| 1301 | );
|
---|
| 1302 | if (opt & (OPT_h|OPT_H)) {
|
---|
| 1303 | //msg added 2011-11
|
---|
| 1304 | bb_error_msg("option -h NAME is deprecated, use -x hostname:NAME");
|
---|
[1765] | 1305 | client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
|
---|
[3232] | 1306 | }
|
---|
[1765] | 1307 | if (opt & OPT_F) {
|
---|
[2725] | 1308 | /* FQDN option format: [0x51][len][flags][0][0]<fqdn> */
|
---|
[1765] | 1309 | client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
|
---|
[2725] | 1310 | /* Flag bits: 0000NEOS
|
---|
| 1311 | * S: 1 = Client requests server to update A RR in DNS as well as PTR
|
---|
| 1312 | * O: 1 = Server indicates to client that DNS has been updated regardless
|
---|
| 1313 | * E: 1 = Name is in DNS format, i.e. <4>host<6>domain<3>com<0>,
|
---|
| 1314 | * not "host.domain.com". Format 0 is obsolete.
|
---|
| 1315 | * N: 1 = Client requests server to not update DNS (S must be 0 then)
|
---|
| 1316 | * Two [0] bytes which follow are deprecated and must be 0.
|
---|
| 1317 | */
|
---|
[1765] | 1318 | client_config.fqdn[OPT_DATA + 0] = 0x1;
|
---|
[2725] | 1319 | /*client_config.fqdn[OPT_DATA + 1] = 0; - xzalloc did it */
|
---|
| 1320 | /*client_config.fqdn[OPT_DATA + 2] = 0; */
|
---|
[821] | 1321 | }
|
---|
[1765] | 1322 | if (opt & OPT_r)
|
---|
| 1323 | requested_ip = inet_addr(str_r);
|
---|
[2725] | 1324 | #if ENABLE_FEATURE_UDHCP_PORT
|
---|
| 1325 | if (opt & OPT_P) {
|
---|
| 1326 | CLIENT_PORT = xatou16(str_P);
|
---|
| 1327 | SERVER_PORT = CLIENT_PORT - 1;
|
---|
[1765] | 1328 | }
|
---|
[2725] | 1329 | #endif
|
---|
[3621] | 1330 | IF_FEATURE_UDHCPC_ARPING(arpping_ms = xatou(str_a);)
|
---|
[2725] | 1331 | while (list_O) {
|
---|
| 1332 | char *optstr = llist_pop(&list_O);
|
---|
[3232] | 1333 | unsigned n = bb_strtou(optstr, NULL, 0);
|
---|
| 1334 | if (errno || n > 254) {
|
---|
| 1335 | n = udhcp_option_idx(optstr);
|
---|
| 1336 | n = dhcp_optflags[n].code;
|
---|
| 1337 | }
|
---|
[2725] | 1338 | client_config.opt_mask[n >> 3] |= 1 << (n & 7);
|
---|
| 1339 | }
|
---|
[3232] | 1340 | if (!(opt & OPT_o)) {
|
---|
| 1341 | unsigned i, n;
|
---|
| 1342 | for (i = 0; (n = dhcp_optflags[i].code) != 0; i++) {
|
---|
| 1343 | if (dhcp_optflags[i].flags & OPTION_REQ) {
|
---|
| 1344 | client_config.opt_mask[n >> 3] |= 1 << (n & 7);
|
---|
| 1345 | }
|
---|
| 1346 | }
|
---|
| 1347 | }
|
---|
[2725] | 1348 | while (list_x) {
|
---|
| 1349 | char *optstr = llist_pop(&list_x);
|
---|
| 1350 | char *colon = strchr(optstr, ':');
|
---|
| 1351 | if (colon)
|
---|
| 1352 | *colon = ' ';
|
---|
| 1353 | /* now it looks similar to udhcpd's config file line:
|
---|
| 1354 | * "optname optval", using the common routine: */
|
---|
| 1355 | udhcp_str2optset(optstr, &client_config.options);
|
---|
| 1356 | }
|
---|
[821] | 1357 |
|
---|
[2725] | 1358 | if (udhcp_read_interface(client_config.interface,
|
---|
| 1359 | &client_config.ifindex,
|
---|
| 1360 | NULL,
|
---|
| 1361 | client_config.client_mac)
|
---|
| 1362 | ) {
|
---|
| 1363 | return 1;
|
---|
| 1364 | }
|
---|
| 1365 |
|
---|
| 1366 | clientid_mac_ptr = NULL;
|
---|
| 1367 | if (!(opt & OPT_C) && !udhcp_find_option(client_config.options, DHCP_CLIENT_ID)) {
|
---|
| 1368 | /* not suppressed and not set, set the default client ID */
|
---|
| 1369 | client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
|
---|
| 1370 | client_config.clientid[OPT_DATA] = 1; /* type: ethernet */
|
---|
| 1371 | clientid_mac_ptr = client_config.clientid + OPT_DATA+1;
|
---|
| 1372 | memcpy(clientid_mac_ptr, client_config.client_mac, 6);
|
---|
| 1373 | }
|
---|
[3232] | 1374 | if (str_V[0] != '\0') {
|
---|
| 1375 | // can drop -V, str_V, client_config.vendorclass,
|
---|
| 1376 | // but need to add "vendor" to the list of recognized
|
---|
| 1377 | // string opts for this to work;
|
---|
| 1378 | // and need to tweak add_client_options() too...
|
---|
| 1379 | // ...so the question is, should we?
|
---|
| 1380 | //bb_error_msg("option -V VENDOR is deprecated, use -x vendor:VENDOR");
|
---|
[2725] | 1381 | client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
|
---|
[3232] | 1382 | }
|
---|
| 1383 |
|
---|
[2725] | 1384 | #if !BB_MMU
|
---|
| 1385 | /* on NOMMU reexec (i.e., background) early */
|
---|
| 1386 | if (!(opt & OPT_f)) {
|
---|
| 1387 | bb_daemonize_or_rexec(0 /* flags */, argv);
|
---|
| 1388 | logmode = LOGMODE_NONE;
|
---|
| 1389 | }
|
---|
| 1390 | #endif
|
---|
[1765] | 1391 | if (opt & OPT_S) {
|
---|
[2725] | 1392 | openlog(applet_name, LOG_PID, LOG_DAEMON);
|
---|
[1765] | 1393 | logmode |= LOGMODE_SYSLOG;
|
---|
| 1394 | }
|
---|
[821] | 1395 |
|
---|
[1765] | 1396 | /* Make sure fd 0,1,2 are open */
|
---|
| 1397 | bb_sanitize_stdio();
|
---|
| 1398 | /* Equivalent of doing a fflush after every \n */
|
---|
| 1399 | setlinebuf(stdout);
|
---|
| 1400 | /* Create pidfile */
|
---|
| 1401 | write_pidfile(client_config.pidfile);
|
---|
[2725] | 1402 | /* Goes to stdout (unless NOMMU) and possibly syslog */
|
---|
[3621] | 1403 | bb_error_msg("started, v"BB_VER);
|
---|
[2725] | 1404 | /* Set up the signal pipe */
|
---|
[821] | 1405 | udhcp_sp_setup();
|
---|
[2725] | 1406 | /* We want random_xid to be random... */
|
---|
| 1407 | srand(monotonic_us());
|
---|
[821] | 1408 |
|
---|
| 1409 | state = INIT_SELECTING;
|
---|
| 1410 | udhcp_run_script(NULL, "deconfig");
|
---|
[2725] | 1411 | change_listen_mode(LISTEN_RAW);
|
---|
| 1412 | packet_num = 0;
|
---|
| 1413 | timeout = 0;
|
---|
| 1414 | already_waited_sec = 0;
|
---|
[821] | 1415 |
|
---|
[2725] | 1416 | /* Main event loop. select() waits on signal pipe and possibly
|
---|
| 1417 | * on sockfd.
|
---|
| 1418 | * "continue" statements in code below jump to the top of the loop.
|
---|
| 1419 | */
|
---|
[821] | 1420 | for (;;) {
|
---|
[3232] | 1421 | struct timeval tv;
|
---|
| 1422 | struct dhcp_packet packet;
|
---|
[2725] | 1423 | /* silence "uninitialized!" warning */
|
---|
| 1424 | unsigned timestamp_before_wait = timestamp_before_wait;
|
---|
[821] | 1425 |
|
---|
[2725] | 1426 | //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
|
---|
| 1427 |
|
---|
| 1428 | /* Was opening raw or udp socket here
|
---|
| 1429 | * if (listen_mode != LISTEN_NONE && sockfd < 0),
|
---|
| 1430 | * but on fast network renew responses return faster
|
---|
| 1431 | * than we open sockets. Thus this code is moved
|
---|
| 1432 | * to change_listen_mode(). Thus we open listen socket
|
---|
| 1433 | * BEFORE we send renew request (see "case BOUND:"). */
|
---|
| 1434 |
|
---|
[1765] | 1435 | max_fd = udhcp_sp_fd_set(&rfds, sockfd);
|
---|
[821] | 1436 |
|
---|
[2725] | 1437 | tv.tv_sec = timeout - already_waited_sec;
|
---|
| 1438 | tv.tv_usec = 0;
|
---|
| 1439 | retval = 0;
|
---|
| 1440 | /* If we already timed out, fall through with retval = 0, else... */
|
---|
| 1441 | if ((int)tv.tv_sec > 0) {
|
---|
[3621] | 1442 | log1("waiting on select %u seconds", (int)tv.tv_sec);
|
---|
[2725] | 1443 | timestamp_before_wait = (unsigned)monotonic_sec();
|
---|
[821] | 1444 | retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
|
---|
[2725] | 1445 | if (retval < 0) {
|
---|
| 1446 | /* EINTR? A signal was caught, don't panic */
|
---|
| 1447 | if (errno == EINTR) {
|
---|
| 1448 | already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
|
---|
| 1449 | continue;
|
---|
| 1450 | }
|
---|
[1765] | 1451 | /* Else: an error occured, panic! */
|
---|
| 1452 | bb_perror_msg_and_die("select");
|
---|
| 1453 | }
|
---|
[2725] | 1454 | }
|
---|
| 1455 |
|
---|
| 1456 | /* If timeout dropped to zero, time to become active:
|
---|
| 1457 | * resend discover/renew/whatever
|
---|
| 1458 | */
|
---|
| 1459 | if (retval == 0) {
|
---|
| 1460 | /* When running on a bridge, the ifindex may have changed
|
---|
| 1461 | * (e.g. if member interfaces were added/removed
|
---|
| 1462 | * or if the status of the bridge changed).
|
---|
| 1463 | * Refresh ifindex and client_mac:
|
---|
| 1464 | */
|
---|
| 1465 | if (udhcp_read_interface(client_config.interface,
|
---|
| 1466 | &client_config.ifindex,
|
---|
| 1467 | NULL,
|
---|
| 1468 | client_config.client_mac)
|
---|
| 1469 | ) {
|
---|
[3232] | 1470 | goto ret0; /* iface is gone? */
|
---|
[2725] | 1471 | }
|
---|
| 1472 | if (clientid_mac_ptr)
|
---|
| 1473 | memcpy(clientid_mac_ptr, client_config.client_mac, 6);
|
---|
| 1474 |
|
---|
| 1475 | /* We will restart the wait in any case */
|
---|
| 1476 | already_waited_sec = 0;
|
---|
| 1477 |
|
---|
[821] | 1478 | switch (state) {
|
---|
| 1479 | case INIT_SELECTING:
|
---|
[3232] | 1480 | if (!discover_retries || packet_num < discover_retries) {
|
---|
[821] | 1481 | if (packet_num == 0)
|
---|
| 1482 | xid = random_xid();
|
---|
[2725] | 1483 | /* broadcast */
|
---|
| 1484 | send_discover(xid, requested_ip);
|
---|
| 1485 | timeout = discover_timeout;
|
---|
[821] | 1486 | packet_num++;
|
---|
[2725] | 1487 | continue;
|
---|
[821] | 1488 | }
|
---|
[2725] | 1489 | leasefail:
|
---|
| 1490 | udhcp_run_script(NULL, "leasefail");
|
---|
| 1491 | #if BB_MMU /* -b is not supported on NOMMU */
|
---|
| 1492 | if (opt & OPT_b) { /* background if no lease */
|
---|
[3621] | 1493 | bb_error_msg("no lease, forking to background");
|
---|
[2725] | 1494 | client_background();
|
---|
| 1495 | /* do not background again! */
|
---|
| 1496 | opt = ((opt & ~OPT_b) | OPT_f);
|
---|
| 1497 | } else
|
---|
| 1498 | #endif
|
---|
| 1499 | if (opt & OPT_n) { /* abort if no lease */
|
---|
[3621] | 1500 | bb_error_msg("no lease, failing");
|
---|
[2725] | 1501 | retval = 1;
|
---|
| 1502 | goto ret;
|
---|
| 1503 | }
|
---|
| 1504 | /* wait before trying again */
|
---|
| 1505 | timeout = tryagain_timeout;
|
---|
| 1506 | packet_num = 0;
|
---|
| 1507 | continue;
|
---|
[821] | 1508 | case REQUESTING:
|
---|
[3621] | 1509 | if (packet_num < 3) {
|
---|
[2725] | 1510 | /* send broadcast select packet */
|
---|
| 1511 | send_select(xid, server_addr, requested_ip);
|
---|
| 1512 | timeout = discover_timeout;
|
---|
[821] | 1513 | packet_num++;
|
---|
[2725] | 1514 | continue;
|
---|
[821] | 1515 | }
|
---|
[2725] | 1516 | /* Timed out, go back to init state.
|
---|
| 1517 | * "discover...select...discover..." loops
|
---|
| 1518 | * were seen in the wild. Treat them similarly
|
---|
| 1519 | * to "no response to discover" case */
|
---|
| 1520 | change_listen_mode(LISTEN_RAW);
|
---|
| 1521 | state = INIT_SELECTING;
|
---|
| 1522 | goto leasefail;
|
---|
[821] | 1523 | case BOUND:
|
---|
[2725] | 1524 | /* 1/2 lease passed, enter renewing state */
|
---|
[821] | 1525 | state = RENEWING;
|
---|
[3232] | 1526 | client_config.first_secs = 0; /* make secs field count from 0 */
|
---|
[2725] | 1527 | change_listen_mode(LISTEN_KERNEL);
|
---|
[3621] | 1528 | log1("entering renew state");
|
---|
[821] | 1529 | /* fall right through */
|
---|
[2725] | 1530 | case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
|
---|
| 1531 | case_RENEW_REQUESTED:
|
---|
[821] | 1532 | case RENEWING:
|
---|
[2725] | 1533 | if (timeout > 60) {
|
---|
| 1534 | /* send an unicast renew request */
|
---|
| 1535 | /* Sometimes observed to fail (EADDRNOTAVAIL) to bind
|
---|
| 1536 | * a new UDP socket for sending inside send_renew.
|
---|
| 1537 | * I hazard to guess existing listening socket
|
---|
| 1538 | * is somehow conflicting with it, but why is it
|
---|
| 1539 | * not deterministic then?! Strange.
|
---|
| 1540 | * Anyway, it does recover by eventually failing through
|
---|
| 1541 | * into INIT_SELECTING state.
|
---|
| 1542 | */
|
---|
| 1543 | send_renew(xid, server_addr, requested_ip);
|
---|
| 1544 | timeout >>= 1;
|
---|
| 1545 | continue;
|
---|
[821] | 1546 | }
|
---|
[2725] | 1547 | /* Timed out, enter rebinding state */
|
---|
[3621] | 1548 | log1("entering rebinding state");
|
---|
[2725] | 1549 | state = REBINDING;
|
---|
| 1550 | /* fall right through */
|
---|
[821] | 1551 | case REBINDING:
|
---|
[2725] | 1552 | /* Switch to bcast receive */
|
---|
| 1553 | change_listen_mode(LISTEN_RAW);
|
---|
| 1554 | /* Lease is *really* about to run out,
|
---|
| 1555 | * try to find DHCP server using broadcast */
|
---|
| 1556 | if (timeout > 0) {
|
---|
| 1557 | /* send a broadcast renew request */
|
---|
| 1558 | send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
|
---|
| 1559 | timeout >>= 1;
|
---|
| 1560 | continue;
|
---|
[821] | 1561 | }
|
---|
[2725] | 1562 | /* Timed out, enter init state */
|
---|
[3621] | 1563 | bb_error_msg("lease lost, entering init state");
|
---|
[2725] | 1564 | udhcp_run_script(NULL, "deconfig");
|
---|
| 1565 | state = INIT_SELECTING;
|
---|
[3232] | 1566 | client_config.first_secs = 0; /* make secs field count from 0 */
|
---|
[2725] | 1567 | /*timeout = 0; - already is */
|
---|
| 1568 | packet_num = 0;
|
---|
| 1569 | continue;
|
---|
| 1570 | /* case RELEASED: */
|
---|
[821] | 1571 | }
|
---|
[2725] | 1572 | /* yah, I know, *you* say it would never happen */
|
---|
| 1573 | timeout = INT_MAX;
|
---|
| 1574 | continue; /* back to main loop */
|
---|
| 1575 | } /* if select timed out */
|
---|
[821] | 1576 |
|
---|
[2725] | 1577 | /* select() didn't timeout, something happened */
|
---|
[821] | 1578 |
|
---|
[2725] | 1579 | /* Is it a signal? */
|
---|
| 1580 | /* note: udhcp_sp_read checks FD_ISSET before reading */
|
---|
| 1581 | switch (udhcp_sp_read(&rfds)) {
|
---|
| 1582 | case SIGUSR1:
|
---|
[3232] | 1583 | client_config.first_secs = 0; /* make secs field count from 0 */
|
---|
| 1584 | already_waited_sec = 0;
|
---|
[2725] | 1585 | perform_renew();
|
---|
[3232] | 1586 | if (state == RENEW_REQUESTED) {
|
---|
| 1587 | /* We might be either on the same network
|
---|
| 1588 | * (in which case renew might work),
|
---|
| 1589 | * or we might be on a completely different one
|
---|
| 1590 | * (in which case renew won't ever succeed).
|
---|
| 1591 | * For the second case, must make sure timeout
|
---|
| 1592 | * is not too big, or else we can send
|
---|
| 1593 | * futile renew requests for hours.
|
---|
| 1594 | * (Ab)use -A TIMEOUT value (usually 20 sec)
|
---|
| 1595 | * as a cap on the timeout.
|
---|
| 1596 | */
|
---|
| 1597 | if (timeout > tryagain_timeout)
|
---|
| 1598 | timeout = tryagain_timeout;
|
---|
[2725] | 1599 | goto case_RENEW_REQUESTED;
|
---|
[3232] | 1600 | }
|
---|
[2725] | 1601 | /* Start things over */
|
---|
| 1602 | packet_num = 0;
|
---|
| 1603 | /* Kill any timeouts, user wants this to hurry along */
|
---|
| 1604 | timeout = 0;
|
---|
| 1605 | continue;
|
---|
| 1606 | case SIGUSR2:
|
---|
[3232] | 1607 | perform_release(server_addr, requested_ip);
|
---|
[2725] | 1608 | timeout = INT_MAX;
|
---|
| 1609 | continue;
|
---|
| 1610 | case SIGTERM:
|
---|
[3621] | 1611 | bb_error_msg("received %s", "SIGTERM");
|
---|
[2725] | 1612 | goto ret0;
|
---|
| 1613 | }
|
---|
[821] | 1614 |
|
---|
[2725] | 1615 | /* Is it a packet? */
|
---|
| 1616 | if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds))
|
---|
| 1617 | continue; /* no */
|
---|
| 1618 |
|
---|
| 1619 | {
|
---|
| 1620 | int len;
|
---|
| 1621 |
|
---|
| 1622 | /* A packet is ready, read it */
|
---|
| 1623 | if (listen_mode == LISTEN_KERNEL)
|
---|
| 1624 | len = udhcp_recv_kernel_packet(&packet, sockfd);
|
---|
| 1625 | else
|
---|
| 1626 | len = udhcp_recv_raw_packet(&packet, sockfd);
|
---|
| 1627 | if (len == -1) {
|
---|
| 1628 | /* Error is severe, reopen socket */
|
---|
[3621] | 1629 | bb_error_msg("read error: %s, reopening socket", strerror(errno));
|
---|
[2725] | 1630 | sleep(discover_timeout); /* 3 seconds by default */
|
---|
| 1631 | change_listen_mode(listen_mode); /* just close and reopen */
|
---|
[821] | 1632 | }
|
---|
[2725] | 1633 | /* If this packet will turn out to be unrelated/bogus,
|
---|
| 1634 | * we will go back and wait for next one.
|
---|
| 1635 | * Be sure timeout is properly decreased. */
|
---|
| 1636 | already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
|
---|
| 1637 | if (len < 0)
|
---|
[821] | 1638 | continue;
|
---|
[2725] | 1639 | }
|
---|
[821] | 1640 |
|
---|
[2725] | 1641 | if (packet.xid != xid) {
|
---|
| 1642 | log1("xid %x (our is %x), ignoring packet",
|
---|
| 1643 | (unsigned)packet.xid, (unsigned)xid);
|
---|
| 1644 | continue;
|
---|
| 1645 | }
|
---|
| 1646 |
|
---|
| 1647 | /* Ignore packets that aren't for us */
|
---|
| 1648 | if (packet.hlen != 6
|
---|
| 1649 | || memcmp(packet.chaddr, client_config.client_mac, 6) != 0
|
---|
| 1650 | ) {
|
---|
| 1651 | //FIXME: need to also check that last 10 bytes are zero
|
---|
| 1652 | log1("chaddr does not match, ignoring packet"); // log2?
|
---|
| 1653 | continue;
|
---|
| 1654 | }
|
---|
| 1655 |
|
---|
| 1656 | message = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE);
|
---|
| 1657 | if (message == NULL) {
|
---|
| 1658 | bb_error_msg("no message type option, ignoring packet");
|
---|
| 1659 | continue;
|
---|
| 1660 | }
|
---|
| 1661 |
|
---|
| 1662 | switch (state) {
|
---|
| 1663 | case INIT_SELECTING:
|
---|
[3232] | 1664 | /* Must be a DHCPOFFER */
|
---|
[2725] | 1665 | if (*message == DHCPOFFER) {
|
---|
[3621] | 1666 | uint8_t *temp;
|
---|
| 1667 |
|
---|
[3232] | 1668 | /* What exactly is server's IP? There are several values.
|
---|
| 1669 | * Example DHCP offer captured with tchdump:
|
---|
| 1670 | *
|
---|
| 1671 | * 10.34.25.254:67 > 10.34.25.202:68 // IP header's src
|
---|
| 1672 | * BOOTP fields:
|
---|
| 1673 | * Your-IP 10.34.25.202
|
---|
| 1674 | * Server-IP 10.34.32.125 // "next server" IP
|
---|
| 1675 | * Gateway-IP 10.34.25.254 // relay's address (if DHCP relays are in use)
|
---|
| 1676 | * DHCP options:
|
---|
| 1677 | * DHCP-Message Option 53, length 1: Offer
|
---|
| 1678 | * Server-ID Option 54, length 4: 10.34.255.7 // "server ID"
|
---|
| 1679 | * Default-Gateway Option 3, length 4: 10.34.25.254 // router
|
---|
| 1680 | *
|
---|
| 1681 | * We think that real server IP (one to use in renew/release)
|
---|
| 1682 | * is one in Server-ID option. But I am not 100% sure.
|
---|
| 1683 | * IP header's src and Gateway-IP (same in this example)
|
---|
| 1684 | * might work too.
|
---|
| 1685 | * "Next server" and router are definitely wrong ones to use, though...
|
---|
| 1686 | */
|
---|
[3621] | 1687 | /* We used to ignore pcakets without DHCP_SERVER_ID.
|
---|
| 1688 | * I've got user reports from people who run "address-less" servers.
|
---|
| 1689 | * They either supply DHCP_SERVER_ID of 0.0.0.0 or don't supply it at all.
|
---|
| 1690 | * They say ISC DHCP client supports this case.
|
---|
| 1691 | */
|
---|
| 1692 | server_addr = 0;
|
---|
[2725] | 1693 | temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
|
---|
| 1694 | if (!temp) {
|
---|
[3621] | 1695 | bb_error_msg("no server ID, using 0.0.0.0");
|
---|
| 1696 | } else {
|
---|
| 1697 | /* it IS unaligned sometimes, don't "optimize" */
|
---|
| 1698 | move_from_unaligned32(server_addr, temp);
|
---|
[2725] | 1699 | }
|
---|
| 1700 | /*xid = packet.xid; - already is */
|
---|
| 1701 | requested_ip = packet.yiaddr;
|
---|
| 1702 |
|
---|
| 1703 | /* enter requesting state */
|
---|
| 1704 | state = REQUESTING;
|
---|
| 1705 | timeout = 0;
|
---|
| 1706 | packet_num = 0;
|
---|
| 1707 | already_waited_sec = 0;
|
---|
[821] | 1708 | }
|
---|
[2725] | 1709 | continue;
|
---|
| 1710 | case REQUESTING:
|
---|
| 1711 | case RENEWING:
|
---|
| 1712 | case RENEW_REQUESTED:
|
---|
| 1713 | case REBINDING:
|
---|
| 1714 | if (*message == DHCPACK) {
|
---|
[3621] | 1715 | unsigned start;
|
---|
[3232] | 1716 | uint32_t lease_seconds;
|
---|
| 1717 | struct in_addr temp_addr;
|
---|
[3621] | 1718 | uint8_t *temp;
|
---|
[3232] | 1719 |
|
---|
[2725] | 1720 | temp = udhcp_get_option(&packet, DHCP_LEASE_TIME);
|
---|
| 1721 | if (!temp) {
|
---|
| 1722 | bb_error_msg("no lease time with ACK, using 1 hour lease");
|
---|
| 1723 | lease_seconds = 60 * 60;
|
---|
| 1724 | } else {
|
---|
| 1725 | /* it IS unaligned sometimes, don't "optimize" */
|
---|
| 1726 | move_from_unaligned32(lease_seconds, temp);
|
---|
| 1727 | lease_seconds = ntohl(lease_seconds);
|
---|
[3232] | 1728 | /* paranoia: must not be too small and not prone to overflows */
|
---|
| 1729 | if (lease_seconds < 0x10)
|
---|
| 1730 | lease_seconds = 0x10;
|
---|
| 1731 | if (lease_seconds >= 0x10000000)
|
---|
| 1732 | lease_seconds = 0x0fffffff;
|
---|
[2725] | 1733 | }
|
---|
| 1734 | #if ENABLE_FEATURE_UDHCPC_ARPING
|
---|
| 1735 | if (opt & OPT_a) {
|
---|
| 1736 | /* RFC 2131 3.1 paragraph 5:
|
---|
| 1737 | * "The client receives the DHCPACK message with configuration
|
---|
| 1738 | * parameters. The client SHOULD perform a final check on the
|
---|
| 1739 | * parameters (e.g., ARP for allocated network address), and notes
|
---|
| 1740 | * the duration of the lease specified in the DHCPACK message. At this
|
---|
| 1741 | * point, the client is configured. If the client detects that the
|
---|
| 1742 | * address is already in use (e.g., through the use of ARP),
|
---|
| 1743 | * the client MUST send a DHCPDECLINE message to the server and restarts
|
---|
| 1744 | * the configuration process..." */
|
---|
| 1745 | if (!arpping(packet.yiaddr,
|
---|
| 1746 | NULL,
|
---|
| 1747 | (uint32_t) 0,
|
---|
| 1748 | client_config.client_mac,
|
---|
[3621] | 1749 | client_config.interface,
|
---|
| 1750 | arpping_ms)
|
---|
[2725] | 1751 | ) {
|
---|
[3621] | 1752 | bb_error_msg("offered address is in use "
|
---|
[2725] | 1753 | "(got ARP reply), declining");
|
---|
[3232] | 1754 | send_decline(/*xid,*/ server_addr, packet.yiaddr);
|
---|
[821] | 1755 |
|
---|
[2725] | 1756 | if (state != REQUESTING)
|
---|
| 1757 | udhcp_run_script(NULL, "deconfig");
|
---|
| 1758 | change_listen_mode(LISTEN_RAW);
|
---|
| 1759 | state = INIT_SELECTING;
|
---|
[3232] | 1760 | client_config.first_secs = 0; /* make secs field count from 0 */
|
---|
[2725] | 1761 | requested_ip = 0;
|
---|
| 1762 | timeout = tryagain_timeout;
|
---|
[821] | 1763 | packet_num = 0;
|
---|
[2725] | 1764 | already_waited_sec = 0;
|
---|
| 1765 | continue; /* back to main loop */
|
---|
[821] | 1766 | }
|
---|
| 1767 | }
|
---|
[2725] | 1768 | #endif
|
---|
| 1769 | /* enter bound state */
|
---|
[3232] | 1770 | temp_addr.s_addr = packet.yiaddr;
|
---|
[3621] | 1771 | bb_error_msg("lease of %s obtained, lease time %u",
|
---|
[3232] | 1772 | inet_ntoa(temp_addr), (unsigned)lease_seconds);
|
---|
[2725] | 1773 | requested_ip = packet.yiaddr;
|
---|
[3621] | 1774 |
|
---|
| 1775 | start = monotonic_sec();
|
---|
[2725] | 1776 | udhcp_run_script(&packet, state == REQUESTING ? "bound" : "renew");
|
---|
[3621] | 1777 | already_waited_sec = (unsigned)monotonic_sec() - start;
|
---|
| 1778 | timeout = lease_seconds / 2;
|
---|
| 1779 | if ((unsigned)timeout < already_waited_sec) {
|
---|
| 1780 | /* Something went wrong. Back to discover state */
|
---|
| 1781 | timeout = already_waited_sec = 0;
|
---|
| 1782 | }
|
---|
[821] | 1783 |
|
---|
[2725] | 1784 | state = BOUND;
|
---|
| 1785 | change_listen_mode(LISTEN_NONE);
|
---|
| 1786 | if (opt & OPT_q) { /* quit after lease */
|
---|
| 1787 | goto ret0;
|
---|
[821] | 1788 | }
|
---|
[2725] | 1789 | /* future renew failures should not exit (JM) */
|
---|
| 1790 | opt &= ~OPT_n;
|
---|
| 1791 | #if BB_MMU /* NOMMU case backgrounded earlier */
|
---|
| 1792 | if (!(opt & OPT_f)) {
|
---|
| 1793 | client_background();
|
---|
| 1794 | /* do not background again! */
|
---|
| 1795 | opt = ((opt & ~OPT_b) | OPT_f);
|
---|
| 1796 | }
|
---|
| 1797 | #endif
|
---|
[3232] | 1798 | /* make future renew packets use different xid */
|
---|
| 1799 | /* xid = random_xid(); ...but why bother? */
|
---|
[3621] | 1800 |
|
---|
[2725] | 1801 | continue; /* back to main loop */
|
---|
[821] | 1802 | }
|
---|
[2725] | 1803 | if (*message == DHCPNAK) {
|
---|
[3621] | 1804 | /* If network has more than one DHCP server,
|
---|
| 1805 | * "wrong" server can reply first, with a NAK.
|
---|
| 1806 | * Do not interpret it as a NAK from "our" server.
|
---|
| 1807 | */
|
---|
| 1808 | if (server_addr != 0) {
|
---|
| 1809 | uint32_t svid;
|
---|
| 1810 | uint8_t *temp;
|
---|
| 1811 |
|
---|
| 1812 | temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
|
---|
| 1813 | if (!temp) {
|
---|
| 1814 | non_matching_svid:
|
---|
| 1815 | log1("%s with wrong server ID, ignoring packet",
|
---|
| 1816 | "Received DHCP NAK"
|
---|
| 1817 | );
|
---|
| 1818 | continue;
|
---|
| 1819 | }
|
---|
| 1820 | move_from_unaligned32(svid, temp);
|
---|
| 1821 | if (svid != server_addr)
|
---|
| 1822 | goto non_matching_svid;
|
---|
| 1823 | }
|
---|
[2725] | 1824 | /* return to init state */
|
---|
[3621] | 1825 | bb_error_msg("received %s", "DHCP NAK");
|
---|
[2725] | 1826 | udhcp_run_script(&packet, "nak");
|
---|
| 1827 | if (state != REQUESTING)
|
---|
| 1828 | udhcp_run_script(NULL, "deconfig");
|
---|
| 1829 | change_listen_mode(LISTEN_RAW);
|
---|
| 1830 | sleep(3); /* avoid excessive network traffic */
|
---|
| 1831 | state = INIT_SELECTING;
|
---|
[3232] | 1832 | client_config.first_secs = 0; /* make secs field count from 0 */
|
---|
[2725] | 1833 | requested_ip = 0;
|
---|
| 1834 | timeout = 0;
|
---|
| 1835 | packet_num = 0;
|
---|
| 1836 | already_waited_sec = 0;
|
---|
[821] | 1837 | }
|
---|
[2725] | 1838 | continue;
|
---|
| 1839 | /* case BOUND: - ignore all packets */
|
---|
| 1840 | /* case RELEASED: - ignore all packets */
|
---|
[821] | 1841 | }
|
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[2725] | 1842 | /* back to main loop */
|
---|
| 1843 | } /* for (;;) - main loop ends */
|
---|
| 1844 |
|
---|
[1765] | 1845 | ret0:
|
---|
[3232] | 1846 | if (opt & OPT_R) /* release on quit */
|
---|
| 1847 | perform_release(server_addr, requested_ip);
|
---|
[1765] | 1848 | retval = 0;
|
---|
| 1849 | ret:
|
---|
[2725] | 1850 | /*if (client_config.pidfile) - remove_pidfile has its own check */
|
---|
[1765] | 1851 | remove_pidfile(client_config.pidfile);
|
---|
| 1852 | return retval;
|
---|
[821] | 1853 | }
|
---|