52a515d187
function old new delta udhcp_sp_read 65 46 -19 udhcp_sp_fd_set 79 54 -25 udhcpd_main 1530 1482 -48 udhcpc_main 2780 2730 -50 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 0/4 up/down: 0/-142) Total: -142 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
1865 lines
58 KiB
C
1865 lines
58 KiB
C
/* vi: set sw=4 ts=4: */
|
|
/*
|
|
* udhcp client
|
|
*
|
|
* Russ Dill <Russ.Dill@asu.edu> July 2001
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*/
|
|
//applet:IF_UDHCPC(APPLET(udhcpc, BB_DIR_SBIN, BB_SUID_DROP))
|
|
|
|
//kbuild:lib-$(CONFIG_UDHCPC) += common.o packet.o signalpipe.o socket.o
|
|
//kbuild:lib-$(CONFIG_UDHCPC) += dhcpc.o
|
|
//kbuild:lib-$(CONFIG_FEATURE_UDHCPC_ARPING) += arpping.o
|
|
//kbuild:lib-$(CONFIG_FEATURE_UDHCP_RFC3397) += domain_codec.o
|
|
|
|
#include <syslog.h>
|
|
/* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
|
|
#define WANT_PIDFILE 1
|
|
#include "common.h"
|
|
#include "dhcpd.h"
|
|
#include "dhcpc.h"
|
|
|
|
#include <netinet/if_ether.h>
|
|
#include <linux/filter.h>
|
|
#include <linux/if_packet.h>
|
|
|
|
#ifndef PACKET_AUXDATA
|
|
# define PACKET_AUXDATA 8
|
|
struct tpacket_auxdata {
|
|
uint32_t tp_status;
|
|
uint32_t tp_len;
|
|
uint32_t tp_snaplen;
|
|
uint16_t tp_mac;
|
|
uint16_t tp_net;
|
|
uint16_t tp_vlan_tci;
|
|
uint16_t tp_padding;
|
|
};
|
|
#endif
|
|
|
|
|
|
/* "struct client_config_t client_config" is in bb_common_bufsiz1 */
|
|
|
|
|
|
#if ENABLE_LONG_OPTS
|
|
static const char udhcpc_longopts[] ALIGN1 =
|
|
"clientid-none\0" No_argument "C"
|
|
"vendorclass\0" Required_argument "V"
|
|
"hostname\0" Required_argument "H"
|
|
"fqdn\0" Required_argument "F"
|
|
"interface\0" Required_argument "i"
|
|
"now\0" No_argument "n"
|
|
"pidfile\0" Required_argument "p"
|
|
"quit\0" No_argument "q"
|
|
"release\0" No_argument "R"
|
|
"request\0" Required_argument "r"
|
|
"script\0" Required_argument "s"
|
|
"timeout\0" Required_argument "T"
|
|
"retries\0" Required_argument "t"
|
|
"tryagain\0" Required_argument "A"
|
|
"syslog\0" No_argument "S"
|
|
"request-option\0" Required_argument "O"
|
|
"no-default-options\0" No_argument "o"
|
|
"foreground\0" No_argument "f"
|
|
"background\0" No_argument "b"
|
|
"broadcast\0" No_argument "B"
|
|
IF_FEATURE_UDHCPC_ARPING("arping\0" Optional_argument "a")
|
|
IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
|
|
;
|
|
#endif
|
|
/* Must match getopt32 option string order */
|
|
enum {
|
|
OPT_C = 1 << 0,
|
|
OPT_V = 1 << 1,
|
|
OPT_H = 1 << 2,
|
|
OPT_h = 1 << 3,
|
|
OPT_F = 1 << 4,
|
|
OPT_i = 1 << 5,
|
|
OPT_n = 1 << 6,
|
|
OPT_p = 1 << 7,
|
|
OPT_q = 1 << 8,
|
|
OPT_R = 1 << 9,
|
|
OPT_r = 1 << 10,
|
|
OPT_s = 1 << 11,
|
|
OPT_T = 1 << 12,
|
|
OPT_t = 1 << 13,
|
|
OPT_S = 1 << 14,
|
|
OPT_A = 1 << 15,
|
|
OPT_O = 1 << 16,
|
|
OPT_o = 1 << 17,
|
|
OPT_x = 1 << 18,
|
|
OPT_f = 1 << 19,
|
|
OPT_B = 1 << 20,
|
|
/* The rest has variable bit positions, need to be clever */
|
|
OPTBIT_B = 20,
|
|
USE_FOR_MMU( OPTBIT_b,)
|
|
IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
|
|
IF_FEATURE_UDHCP_PORT( OPTBIT_P,)
|
|
USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
|
|
IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
|
|
IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
|
|
};
|
|
|
|
|
|
/*** Script execution code ***/
|
|
|
|
/* get a rough idea of how long an option will be (rounding up...) */
|
|
static const uint8_t len_of_option_as_string[] ALIGN1 = {
|
|
[OPTION_IP ] = sizeof("255.255.255.255 "),
|
|
[OPTION_IP_PAIR ] = sizeof("255.255.255.255 ") * 2,
|
|
[OPTION_STATIC_ROUTES ] = sizeof("255.255.255.255/32 255.255.255.255 "),
|
|
[OPTION_6RD ] = sizeof("132 128 ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff 255.255.255.255 "),
|
|
[OPTION_STRING ] = 1,
|
|
[OPTION_STRING_HOST ] = 1,
|
|
#if ENABLE_FEATURE_UDHCP_RFC3397
|
|
[OPTION_DNS_STRING ] = 1, /* unused */
|
|
/* Hmmm, this severely overestimates size if SIP_SERVERS option
|
|
* is in domain name form: N-byte option in binary form
|
|
* mallocs ~16*N bytes. But it is freed almost at once.
|
|
*/
|
|
[OPTION_SIP_SERVERS ] = sizeof("255.255.255.255 "),
|
|
#endif
|
|
// [OPTION_BOOLEAN ] = sizeof("yes "),
|
|
[OPTION_U8 ] = sizeof("255 "),
|
|
[OPTION_U16 ] = sizeof("65535 "),
|
|
// [OPTION_S16 ] = sizeof("-32768 "),
|
|
[OPTION_U32 ] = sizeof("4294967295 "),
|
|
[OPTION_S32 ] = sizeof("-2147483684 "),
|
|
};
|
|
|
|
/* note: ip is a pointer to an IP in network order, possibly misaliged */
|
|
static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
|
|
{
|
|
return sprintf(dest, "%s%u.%u.%u.%u", pre, ip[0], ip[1], ip[2], ip[3]);
|
|
}
|
|
|
|
/* really simple implementation, just count the bits */
|
|
static int mton(uint32_t mask)
|
|
{
|
|
int i = 0;
|
|
mask = ntohl(mask); /* 111110000-like bit pattern */
|
|
while (mask) {
|
|
i++;
|
|
mask <<= 1;
|
|
}
|
|
return i;
|
|
}
|
|
|
|
#if ENABLE_FEATURE_UDHCPC_SANITIZEOPT
|
|
/* Check if a given label represents a valid DNS label
|
|
* Return pointer to the first character after the label upon success,
|
|
* NULL otherwise.
|
|
* See RFC1035, 2.3.1
|
|
*/
|
|
/* We don't need to be particularly anal. For example, allowing _, hyphen
|
|
* at the end, or leading and trailing dots would be ok, since it
|
|
* can't be used for attacks. (Leading hyphen can be, if someone uses
|
|
* cmd "$hostname"
|
|
* in the script: then hostname may be treated as an option)
|
|
*/
|
|
static const char *valid_domain_label(const char *label)
|
|
{
|
|
unsigned char ch;
|
|
unsigned pos = 0;
|
|
|
|
for (;;) {
|
|
ch = *label;
|
|
if ((ch|0x20) < 'a' || (ch|0x20) > 'z') {
|
|
if (ch < '0' || ch > '9') {
|
|
if (ch == '\0' || ch == '.')
|
|
return label;
|
|
/* DNS allows only '-', but we are more permissive */
|
|
if (ch != '-' && ch != '_')
|
|
return NULL;
|
|
}
|
|
}
|
|
label++;
|
|
pos++;
|
|
//Do we want this?
|
|
//if (pos > 63) /* NS_MAXLABEL; labels must be 63 chars or less */
|
|
// return NULL;
|
|
}
|
|
}
|
|
|
|
/* Check if a given name represents a valid DNS name */
|
|
/* See RFC1035, 2.3.1 */
|
|
static int good_hostname(const char *name)
|
|
{
|
|
//const char *start = name;
|
|
|
|
for (;;) {
|
|
name = valid_domain_label(name);
|
|
if (!name)
|
|
return 0;
|
|
if (!name[0])
|
|
return 1;
|
|
//Do we want this?
|
|
//return ((name - start) < 1025); /* NS_MAXDNAME */
|
|
name++;
|
|
if (*name == '\0')
|
|
return 1; // We allow trailing dot too
|
|
}
|
|
}
|
|
#else
|
|
# define good_hostname(name) 1
|
|
#endif
|
|
|
|
/* Create "opt_name=opt_value" string */
|
|
static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_optflag *optflag, const char *opt_name)
|
|
{
|
|
unsigned upper_length;
|
|
int len, type, optlen;
|
|
char *dest, *ret;
|
|
|
|
/* option points to OPT_DATA, need to go back to get OPT_LEN */
|
|
len = option[-OPT_DATA + OPT_LEN];
|
|
|
|
type = optflag->flags & OPTION_TYPE_MASK;
|
|
optlen = dhcp_option_lengths[type];
|
|
upper_length = len_of_option_as_string[type]
|
|
* ((unsigned)(len + optlen) / (unsigned)optlen);
|
|
|
|
dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
|
|
dest += sprintf(ret, "%s=", opt_name);
|
|
|
|
while (len >= optlen) {
|
|
switch (type) {
|
|
case OPTION_IP:
|
|
case OPTION_IP_PAIR:
|
|
dest += sprint_nip(dest, "", option);
|
|
if (type == OPTION_IP)
|
|
break;
|
|
dest += sprint_nip(dest, "/", option + 4);
|
|
break;
|
|
// case OPTION_BOOLEAN:
|
|
// dest += sprintf(dest, *option ? "yes" : "no");
|
|
// break;
|
|
case OPTION_U8:
|
|
dest += sprintf(dest, "%u", *option);
|
|
break;
|
|
// case OPTION_S16:
|
|
case OPTION_U16: {
|
|
uint16_t val_u16;
|
|
move_from_unaligned16(val_u16, option);
|
|
dest += sprintf(dest, "%u", ntohs(val_u16));
|
|
break;
|
|
}
|
|
case OPTION_S32:
|
|
case OPTION_U32: {
|
|
uint32_t val_u32;
|
|
move_from_unaligned32(val_u32, option);
|
|
dest += sprintf(dest, type == OPTION_U32 ? "%lu" : "%ld", (unsigned long) ntohl(val_u32));
|
|
break;
|
|
}
|
|
/* Note: options which use 'return' instead of 'break'
|
|
* (for example, OPTION_STRING) skip the code which handles
|
|
* the case of list of options.
|
|
*/
|
|
case OPTION_STRING:
|
|
case OPTION_STRING_HOST:
|
|
memcpy(dest, option, len);
|
|
dest[len] = '\0';
|
|
if (type == OPTION_STRING_HOST && !good_hostname(dest))
|
|
safe_strncpy(dest, "bad", len);
|
|
return ret;
|
|
case OPTION_STATIC_ROUTES: {
|
|
/* Option binary format:
|
|
* mask [one byte, 0..32]
|
|
* ip [big endian, 0..4 bytes depending on mask]
|
|
* router [big endian, 4 bytes]
|
|
* may be repeated
|
|
*
|
|
* We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
|
|
*/
|
|
const char *pfx = "";
|
|
|
|
while (len >= 1 + 4) { /* mask + 0-byte ip + router */
|
|
uint32_t nip;
|
|
uint8_t *p;
|
|
unsigned mask;
|
|
int bytes;
|
|
|
|
mask = *option++;
|
|
if (mask > 32)
|
|
break;
|
|
len--;
|
|
|
|
nip = 0;
|
|
p = (void*) &nip;
|
|
bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
|
|
while (--bytes >= 0) {
|
|
*p++ = *option++;
|
|
len--;
|
|
}
|
|
if (len < 4)
|
|
break;
|
|
|
|
/* print ip/mask */
|
|
dest += sprint_nip(dest, pfx, (void*) &nip);
|
|
pfx = " ";
|
|
dest += sprintf(dest, "/%u ", mask);
|
|
/* print router */
|
|
dest += sprint_nip(dest, "", option);
|
|
option += 4;
|
|
len -= 4;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
case OPTION_6RD:
|
|
/* Option binary format (see RFC 5969):
|
|
* 0 1 2 3
|
|
* 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
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* | OPTION_6RD | option-length | IPv4MaskLen | 6rdPrefixLen |
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* | 6rdPrefix |
|
|
* ... (16 octets) ...
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* ... 6rdBRIPv4Address(es) ...
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
* We convert it to a string
|
|
* "IPv4MaskLen 6rdPrefixLen 6rdPrefix 6rdBRIPv4Address..."
|
|
*
|
|
* Sanity check: ensure that our length is at least 22 bytes, that
|
|
* IPv4MaskLen <= 32,
|
|
* 6rdPrefixLen <= 128,
|
|
* 6rdPrefixLen + (32 - IPv4MaskLen) <= 128
|
|
* (2nd condition need no check - it follows from 1st and 3rd).
|
|
* Else, return envvar with empty value ("optname=")
|
|
*/
|
|
if (len >= (1 + 1 + 16 + 4)
|
|
&& option[0] <= 32
|
|
&& (option[1] + 32 - option[0]) <= 128
|
|
) {
|
|
/* IPv4MaskLen */
|
|
dest += sprintf(dest, "%u ", *option++);
|
|
/* 6rdPrefixLen */
|
|
dest += sprintf(dest, "%u ", *option++);
|
|
/* 6rdPrefix */
|
|
dest += sprint_nip6(dest, /* "", */ option);
|
|
option += 16;
|
|
len -= 1 + 1 + 16 + 4;
|
|
/* "+ 4" above corresponds to the length of IPv4 addr
|
|
* we consume in the loop below */
|
|
while (1) {
|
|
/* 6rdBRIPv4Address(es) */
|
|
dest += sprint_nip(dest, " ", option);
|
|
option += 4;
|
|
len -= 4; /* do we have yet another 4+ bytes? */
|
|
if (len < 0)
|
|
break; /* no */
|
|
}
|
|
}
|
|
|
|
return ret;
|
|
#if ENABLE_FEATURE_UDHCP_RFC3397
|
|
case OPTION_DNS_STRING:
|
|
/* unpack option into dest; use ret for prefix (i.e., "optname=") */
|
|
dest = dname_dec(option, len, ret);
|
|
if (dest) {
|
|
free(ret);
|
|
return dest;
|
|
}
|
|
/* error. return "optname=" string */
|
|
return ret;
|
|
case OPTION_SIP_SERVERS:
|
|
/* Option binary format:
|
|
* type: byte
|
|
* type=0: domain names, dns-compressed
|
|
* type=1: IP addrs
|
|
*/
|
|
option++;
|
|
len--;
|
|
if (option[-1] == 0) {
|
|
dest = dname_dec(option, len, ret);
|
|
if (dest) {
|
|
free(ret);
|
|
return dest;
|
|
}
|
|
} else
|
|
if (option[-1] == 1) {
|
|
const char *pfx = "";
|
|
while (1) {
|
|
len -= 4;
|
|
if (len < 0)
|
|
break;
|
|
dest += sprint_nip(dest, pfx, option);
|
|
pfx = " ";
|
|
option += 4;
|
|
}
|
|
}
|
|
return ret;
|
|
#endif
|
|
} /* switch */
|
|
|
|
/* If we are here, try to format any remaining data
|
|
* in the option as another, similarly-formatted option
|
|
*/
|
|
option += optlen;
|
|
len -= optlen;
|
|
// TODO: it can be a list only if (optflag->flags & OPTION_LIST).
|
|
// Should we bail out/warn if we see multi-ip option which is
|
|
// not allowed to be such (for example, DHCP_BROADCAST)? -
|
|
if (len < optlen /* || !(optflag->flags & OPTION_LIST) */)
|
|
break;
|
|
*dest++ = ' ';
|
|
*dest = '\0';
|
|
} /* while */
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* put all the parameters into the environment */
|
|
static char **fill_envp(struct dhcp_packet *packet)
|
|
{
|
|
int envc;
|
|
int i;
|
|
char **envp, **curr;
|
|
const char *opt_name;
|
|
uint8_t *temp;
|
|
uint8_t overload = 0;
|
|
|
|
#define BITMAP unsigned
|
|
#define BBITS (sizeof(BITMAP) * 8)
|
|
#define BMASK(i) (1 << (i & (sizeof(BITMAP) * 8 - 1)))
|
|
#define FOUND_OPTS(i) (found_opts[(unsigned)i / BBITS])
|
|
BITMAP found_opts[256 / BBITS];
|
|
|
|
memset(found_opts, 0, sizeof(found_opts));
|
|
|
|
/* We need 6 elements for:
|
|
* "interface=IFACE"
|
|
* "ip=N.N.N.N" from packet->yiaddr
|
|
* "siaddr=IP" from packet->siaddr_nip (unless 0)
|
|
* "boot_file=FILE" from packet->file (unless overloaded)
|
|
* "sname=SERVER_HOSTNAME" from packet->sname (unless overloaded)
|
|
* terminating NULL
|
|
*/
|
|
envc = 6;
|
|
/* +1 element for each option, +2 for subnet option: */
|
|
if (packet) {
|
|
/* note: do not search for "pad" (0) and "end" (255) options */
|
|
//TODO: change logic to scan packet _once_
|
|
for (i = 1; i < 255; i++) {
|
|
temp = udhcp_get_option(packet, i);
|
|
if (temp) {
|
|
if (i == DHCP_OPTION_OVERLOAD)
|
|
overload |= *temp;
|
|
else if (i == DHCP_SUBNET)
|
|
envc++; /* for $mask */
|
|
envc++;
|
|
/*if (i != DHCP_MESSAGE_TYPE)*/
|
|
FOUND_OPTS(i) |= BMASK(i);
|
|
}
|
|
}
|
|
}
|
|
curr = envp = xzalloc(sizeof(envp[0]) * envc);
|
|
|
|
*curr = xasprintf("interface=%s", client_config.interface);
|
|
putenv(*curr++);
|
|
|
|
if (!packet)
|
|
return envp;
|
|
|
|
/* Export BOOTP fields. Fields we don't (yet?) export:
|
|
* uint8_t op; // always BOOTREPLY
|
|
* uint8_t htype; // hardware address type. 1 = 10mb ethernet
|
|
* uint8_t hlen; // hardware address length
|
|
* uint8_t hops; // used by relay agents only
|
|
* uint32_t xid;
|
|
* uint16_t secs; // elapsed since client began acquisition/renewal
|
|
* uint16_t flags; // only one flag so far: bcast. Never set by server
|
|
* uint32_t ciaddr; // client IP (usually == yiaddr. can it be different
|
|
* // if during renew server wants to give us different IP?)
|
|
* uint32_t gateway_nip; // relay agent IP address
|
|
* uint8_t chaddr[16]; // link-layer client hardware address (MAC)
|
|
* TODO: export gateway_nip as $giaddr?
|
|
*/
|
|
/* Most important one: yiaddr as $ip */
|
|
*curr = xmalloc(sizeof("ip=255.255.255.255"));
|
|
sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr);
|
|
putenv(*curr++);
|
|
if (packet->siaddr_nip) {
|
|
/* IP address of next server to use in bootstrap */
|
|
*curr = xmalloc(sizeof("siaddr=255.255.255.255"));
|
|
sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip);
|
|
putenv(*curr++);
|
|
}
|
|
if (!(overload & FILE_FIELD) && packet->file[0]) {
|
|
/* watch out for invalid packets */
|
|
*curr = xasprintf("boot_file=%."DHCP_PKT_FILE_LEN_STR"s", packet->file);
|
|
putenv(*curr++);
|
|
}
|
|
if (!(overload & SNAME_FIELD) && packet->sname[0]) {
|
|
/* watch out for invalid packets */
|
|
*curr = xasprintf("sname=%."DHCP_PKT_SNAME_LEN_STR"s", packet->sname);
|
|
putenv(*curr++);
|
|
}
|
|
|
|
/* Export known DHCP options */
|
|
opt_name = dhcp_option_strings;
|
|
i = 0;
|
|
while (*opt_name) {
|
|
uint8_t code = dhcp_optflags[i].code;
|
|
BITMAP *found_ptr = &FOUND_OPTS(code);
|
|
BITMAP found_mask = BMASK(code);
|
|
if (!(*found_ptr & found_mask))
|
|
goto next;
|
|
*found_ptr &= ~found_mask; /* leave only unknown options */
|
|
temp = udhcp_get_option(packet, code);
|
|
*curr = xmalloc_optname_optval(temp, &dhcp_optflags[i], opt_name);
|
|
putenv(*curr++);
|
|
if (code == DHCP_SUBNET) {
|
|
/* Subnet option: make things like "$ip/$mask" possible */
|
|
uint32_t subnet;
|
|
move_from_unaligned32(subnet, temp);
|
|
*curr = xasprintf("mask=%u", mton(subnet));
|
|
putenv(*curr++);
|
|
}
|
|
next:
|
|
opt_name += strlen(opt_name) + 1;
|
|
i++;
|
|
}
|
|
/* Export unknown options */
|
|
for (i = 0; i < 256;) {
|
|
BITMAP bitmap = FOUND_OPTS(i);
|
|
if (!bitmap) {
|
|
i += BBITS;
|
|
continue;
|
|
}
|
|
if (bitmap & BMASK(i)) {
|
|
unsigned len, ofs;
|
|
|
|
temp = udhcp_get_option(packet, i);
|
|
/* udhcp_get_option returns ptr to data portion,
|
|
* need to go back to get len
|
|
*/
|
|
len = temp[-OPT_DATA + OPT_LEN];
|
|
*curr = xmalloc(sizeof("optNNN=") + 1 + len*2);
|
|
ofs = sprintf(*curr, "opt%u=", i);
|
|
*bin2hex(*curr + ofs, (void*) temp, len) = '\0';
|
|
putenv(*curr++);
|
|
}
|
|
i++;
|
|
}
|
|
|
|
return envp;
|
|
}
|
|
|
|
/* Call a script with a par file and env vars */
|
|
static void udhcp_run_script(struct dhcp_packet *packet, const char *name)
|
|
{
|
|
char **envp, **curr;
|
|
char *argv[3];
|
|
|
|
envp = fill_envp(packet);
|
|
|
|
/* call script */
|
|
log1("executing %s %s", client_config.script, name);
|
|
argv[0] = (char*) client_config.script;
|
|
argv[1] = (char*) name;
|
|
argv[2] = NULL;
|
|
spawn_and_wait(argv);
|
|
|
|
for (curr = envp; *curr; curr++) {
|
|
log2(" %s", *curr);
|
|
bb_unsetenv_and_free(*curr);
|
|
}
|
|
free(envp);
|
|
}
|
|
|
|
|
|
/*** Sending/receiving packets ***/
|
|
|
|
static ALWAYS_INLINE uint32_t random_xid(void)
|
|
{
|
|
return rand();
|
|
}
|
|
|
|
/* Initialize the packet with the proper defaults */
|
|
static void init_packet(struct dhcp_packet *packet, char type)
|
|
{
|
|
uint16_t secs;
|
|
|
|
/* Fill in: op, htype, hlen, cookie fields; message type option: */
|
|
udhcp_init_header(packet, type);
|
|
|
|
packet->xid = random_xid();
|
|
|
|
client_config.last_secs = monotonic_sec();
|
|
if (client_config.first_secs == 0)
|
|
client_config.first_secs = client_config.last_secs;
|
|
secs = client_config.last_secs - client_config.first_secs;
|
|
packet->secs = htons(secs);
|
|
|
|
memcpy(packet->chaddr, client_config.client_mac, 6);
|
|
if (client_config.clientid)
|
|
udhcp_add_binary_option(packet, client_config.clientid);
|
|
}
|
|
|
|
static void add_client_options(struct dhcp_packet *packet)
|
|
{
|
|
int i, end, len;
|
|
|
|
udhcp_add_simple_option(packet, DHCP_MAX_SIZE, htons(IP_UDP_DHCP_SIZE));
|
|
|
|
/* Add a "param req" option with the list of options we'd like to have
|
|
* from stubborn DHCP servers. Pull the data from the struct in common.c.
|
|
* No bounds checking because it goes towards the head of the packet. */
|
|
end = udhcp_end_option(packet->options);
|
|
len = 0;
|
|
for (i = 1; i < DHCP_END; i++) {
|
|
if (client_config.opt_mask[i >> 3] & (1 << (i & 7))) {
|
|
packet->options[end + OPT_DATA + len] = i;
|
|
len++;
|
|
}
|
|
}
|
|
if (len) {
|
|
packet->options[end + OPT_CODE] = DHCP_PARAM_REQ;
|
|
packet->options[end + OPT_LEN] = len;
|
|
packet->options[end + OPT_DATA + len] = DHCP_END;
|
|
}
|
|
|
|
if (client_config.vendorclass)
|
|
udhcp_add_binary_option(packet, client_config.vendorclass);
|
|
if (client_config.hostname)
|
|
udhcp_add_binary_option(packet, client_config.hostname);
|
|
if (client_config.fqdn)
|
|
udhcp_add_binary_option(packet, client_config.fqdn);
|
|
|
|
/* Request broadcast replies if we have no IP addr */
|
|
if ((option_mask32 & OPT_B) && packet->ciaddr == 0)
|
|
packet->flags |= htons(BROADCAST_FLAG);
|
|
|
|
/* Add -x options if any */
|
|
{
|
|
struct option_set *curr = client_config.options;
|
|
while (curr) {
|
|
udhcp_add_binary_option(packet, curr->data);
|
|
curr = curr->next;
|
|
}
|
|
// if (client_config.sname)
|
|
// strncpy((char*)packet->sname, client_config.sname, sizeof(packet->sname) - 1);
|
|
// if (client_config.boot_file)
|
|
// strncpy((char*)packet->file, client_config.boot_file, sizeof(packet->file) - 1);
|
|
}
|
|
|
|
// This will be needed if we remove -V VENDOR_STR in favor of
|
|
// -x vendor:VENDOR_STR
|
|
//if (!udhcp_find_option(packet.options, DHCP_VENDOR))
|
|
// /* not set, set the default vendor ID */
|
|
// ...add (DHCP_VENDOR, "udhcp "BB_VER) opt...
|
|
}
|
|
|
|
/* RFC 2131
|
|
* 4.4.4 Use of broadcast and unicast
|
|
*
|
|
* The DHCP client broadcasts DHCPDISCOVER, DHCPREQUEST and DHCPINFORM
|
|
* messages, unless the client knows the address of a DHCP server.
|
|
* The client unicasts DHCPRELEASE messages to the server. Because
|
|
* the client is declining the use of the IP address supplied by the server,
|
|
* the client broadcasts DHCPDECLINE messages.
|
|
*
|
|
* When the DHCP client knows the address of a DHCP server, in either
|
|
* INIT or REBOOTING state, the client may use that address
|
|
* in the DHCPDISCOVER or DHCPREQUEST rather than the IP broadcast address.
|
|
* The client may also use unicast to send DHCPINFORM messages
|
|
* to a known DHCP server. If the client receives no response to DHCP
|
|
* messages sent to the IP address of a known DHCP server, the DHCP
|
|
* client reverts to using the IP broadcast address.
|
|
*/
|
|
|
|
static int raw_bcast_from_client_config_ifindex(struct dhcp_packet *packet, uint32_t src_nip)
|
|
{
|
|
return udhcp_send_raw_packet(packet,
|
|
/*src*/ src_nip, CLIENT_PORT,
|
|
/*dst*/ INADDR_BROADCAST, SERVER_PORT, MAC_BCAST_ADDR,
|
|
client_config.ifindex);
|
|
}
|
|
|
|
static int bcast_or_ucast(struct dhcp_packet *packet, uint32_t ciaddr, uint32_t server)
|
|
{
|
|
if (server)
|
|
return udhcp_send_kernel_packet(packet,
|
|
ciaddr, CLIENT_PORT,
|
|
server, SERVER_PORT);
|
|
return raw_bcast_from_client_config_ifindex(packet, ciaddr);
|
|
}
|
|
|
|
/* Broadcast a DHCP discover packet to the network, with an optionally requested IP */
|
|
/* NOINLINE: limit stack usage in caller */
|
|
static NOINLINE int send_discover(uint32_t xid, uint32_t requested)
|
|
{
|
|
struct dhcp_packet packet;
|
|
|
|
/* Fill in: op, htype, hlen, cookie, chaddr fields,
|
|
* random xid field (we override it below),
|
|
* client-id option (unless -C), message type option:
|
|
*/
|
|
init_packet(&packet, DHCPDISCOVER);
|
|
|
|
packet.xid = xid;
|
|
if (requested)
|
|
udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
|
|
|
|
/* Add options: maxsize,
|
|
* optionally: hostname, fqdn, vendorclass,
|
|
* "param req" option according to -O, options specified with -x
|
|
*/
|
|
add_client_options(&packet);
|
|
|
|
bb_error_msg("sending %s", "discover");
|
|
return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
|
|
}
|
|
|
|
/* Broadcast a DHCP request message */
|
|
/* RFC 2131 3.1 paragraph 3:
|
|
* "The client _broadcasts_ a DHCPREQUEST message..."
|
|
*/
|
|
/* NOINLINE: limit stack usage in caller */
|
|
static NOINLINE int send_select(uint32_t xid, uint32_t server, uint32_t requested)
|
|
{
|
|
struct dhcp_packet packet;
|
|
struct in_addr addr;
|
|
|
|
/*
|
|
* RFC 2131 4.3.2 DHCPREQUEST message
|
|
* ...
|
|
* If the DHCPREQUEST message contains a 'server identifier'
|
|
* option, the message is in response to a DHCPOFFER message.
|
|
* Otherwise, the message is a request to verify or extend an
|
|
* existing lease. If the client uses a 'client identifier'
|
|
* in a DHCPREQUEST message, it MUST use that same 'client identifier'
|
|
* in all subsequent messages. If the client included a list
|
|
* of requested parameters in a DHCPDISCOVER message, it MUST
|
|
* include that list in all subsequent messages.
|
|
*/
|
|
/* Fill in: op, htype, hlen, cookie, chaddr fields,
|
|
* random xid field (we override it below),
|
|
* client-id option (unless -C), message type option:
|
|
*/
|
|
init_packet(&packet, DHCPREQUEST);
|
|
|
|
packet.xid = xid;
|
|
udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
|
|
|
|
udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
|
|
|
|
/* Add options: maxsize,
|
|
* optionally: hostname, fqdn, vendorclass,
|
|
* "param req" option according to -O, and options specified with -x
|
|
*/
|
|
add_client_options(&packet);
|
|
|
|
addr.s_addr = requested;
|
|
bb_error_msg("sending select for %s", inet_ntoa(addr));
|
|
return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
|
|
}
|
|
|
|
/* Unicast or broadcast a DHCP renew message */
|
|
/* NOINLINE: limit stack usage in caller */
|
|
static NOINLINE int send_renew(uint32_t xid, uint32_t server, uint32_t ciaddr)
|
|
{
|
|
struct dhcp_packet packet;
|
|
|
|
/*
|
|
* RFC 2131 4.3.2 DHCPREQUEST message
|
|
* ...
|
|
* DHCPREQUEST generated during RENEWING state:
|
|
*
|
|
* 'server identifier' MUST NOT be filled in, 'requested IP address'
|
|
* option MUST NOT be filled in, 'ciaddr' MUST be filled in with
|
|
* client's IP address. In this situation, the client is completely
|
|
* configured, and is trying to extend its lease. This message will
|
|
* be unicast, so no relay agents will be involved in its
|
|
* transmission. Because 'giaddr' is therefore not filled in, the
|
|
* DHCP server will trust the value in 'ciaddr', and use it when
|
|
* replying to the client.
|
|
*/
|
|
/* Fill in: op, htype, hlen, cookie, chaddr fields,
|
|
* random xid field (we override it below),
|
|
* client-id option (unless -C), message type option:
|
|
*/
|
|
init_packet(&packet, DHCPREQUEST);
|
|
|
|
packet.xid = xid;
|
|
packet.ciaddr = ciaddr;
|
|
|
|
/* Add options: maxsize,
|
|
* optionally: hostname, fqdn, vendorclass,
|
|
* "param req" option according to -O, and options specified with -x
|
|
*/
|
|
add_client_options(&packet);
|
|
|
|
bb_error_msg("sending %s", "renew");
|
|
return bcast_or_ucast(&packet, ciaddr, server);
|
|
}
|
|
|
|
#if ENABLE_FEATURE_UDHCPC_ARPING
|
|
/* Broadcast a DHCP decline message */
|
|
/* NOINLINE: limit stack usage in caller */
|
|
static NOINLINE int send_decline(/*uint32_t xid,*/ uint32_t server, uint32_t requested)
|
|
{
|
|
struct dhcp_packet packet;
|
|
|
|
/* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
|
|
* client-id option (unless -C), message type option:
|
|
*/
|
|
init_packet(&packet, DHCPDECLINE);
|
|
|
|
#if 0
|
|
/* RFC 2131 says DHCPDECLINE's xid is randomly selected by client,
|
|
* but in case the server is buggy and wants DHCPDECLINE's xid
|
|
* to match the xid which started entire handshake,
|
|
* we use the same xid we used in initial DHCPDISCOVER:
|
|
*/
|
|
packet.xid = xid;
|
|
#endif
|
|
/* DHCPDECLINE uses "requested ip", not ciaddr, to store offered IP */
|
|
udhcp_add_simple_option(&packet, DHCP_REQUESTED_IP, requested);
|
|
|
|
udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
|
|
|
|
bb_error_msg("sending %s", "decline");
|
|
return raw_bcast_from_client_config_ifindex(&packet, INADDR_ANY);
|
|
}
|
|
#endif
|
|
|
|
/* Unicast a DHCP release message */
|
|
static int send_release(uint32_t server, uint32_t ciaddr)
|
|
{
|
|
struct dhcp_packet packet;
|
|
|
|
/* Fill in: op, htype, hlen, cookie, chaddr, random xid fields,
|
|
* client-id option (unless -C), message type option:
|
|
*/
|
|
init_packet(&packet, DHCPRELEASE);
|
|
|
|
/* DHCPRELEASE uses ciaddr, not "requested ip", to store IP being released */
|
|
packet.ciaddr = ciaddr;
|
|
|
|
udhcp_add_simple_option(&packet, DHCP_SERVER_ID, server);
|
|
|
|
bb_error_msg("sending %s", "release");
|
|
/* Note: normally we unicast here since "server" is not zero.
|
|
* However, there _are_ people who run "address-less" DHCP servers,
|
|
* and reportedly ISC dhcp client and Windows allow that.
|
|
*/
|
|
return bcast_or_ucast(&packet, ciaddr, server);
|
|
}
|
|
|
|
/* Returns -1 on errors that are fatal for the socket, -2 for those that aren't */
|
|
/* NOINLINE: limit stack usage in caller */
|
|
static NOINLINE int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd)
|
|
{
|
|
int bytes;
|
|
struct ip_udp_dhcp_packet packet;
|
|
uint16_t check;
|
|
unsigned char cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
|
|
struct iovec iov;
|
|
struct msghdr msg;
|
|
struct cmsghdr *cmsg;
|
|
|
|
/* used to use just safe_read(fd, &packet, sizeof(packet))
|
|
* but we need to check for TP_STATUS_CSUMNOTREADY :(
|
|
*/
|
|
iov.iov_base = &packet;
|
|
iov.iov_len = sizeof(packet);
|
|
memset(&msg, 0, sizeof(msg));
|
|
msg.msg_iov = &iov;
|
|
msg.msg_iovlen = 1;
|
|
msg.msg_control = cmsgbuf;
|
|
msg.msg_controllen = sizeof(cmsgbuf);
|
|
for (;;) {
|
|
bytes = recvmsg(fd, &msg, 0);
|
|
if (bytes < 0) {
|
|
if (errno == EINTR)
|
|
continue;
|
|
log1("packet read error, ignoring");
|
|
/* NB: possible down interface, etc. Caller should pause. */
|
|
return bytes; /* returns -1 */
|
|
}
|
|
break;
|
|
}
|
|
|
|
if (bytes < (int) (sizeof(packet.ip) + sizeof(packet.udp))) {
|
|
log1("packet is too short, ignoring");
|
|
return -2;
|
|
}
|
|
|
|
if (bytes < ntohs(packet.ip.tot_len)) {
|
|
/* packet is bigger than sizeof(packet), we did partial read */
|
|
log1("oversized packet, ignoring");
|
|
return -2;
|
|
}
|
|
|
|
/* ignore any extra garbage bytes */
|
|
bytes = ntohs(packet.ip.tot_len);
|
|
|
|
/* make sure its the right packet for us, and that it passes sanity checks */
|
|
if (packet.ip.protocol != IPPROTO_UDP
|
|
|| packet.ip.version != IPVERSION
|
|
|| packet.ip.ihl != (sizeof(packet.ip) >> 2)
|
|
|| packet.udp.dest != htons(CLIENT_PORT)
|
|
/* || bytes > (int) sizeof(packet) - can't happen */
|
|
|| ntohs(packet.udp.len) != (uint16_t)(bytes - sizeof(packet.ip))
|
|
) {
|
|
log1("unrelated/bogus packet, ignoring");
|
|
return -2;
|
|
}
|
|
|
|
/* verify IP checksum */
|
|
check = packet.ip.check;
|
|
packet.ip.check = 0;
|
|
if (check != inet_cksum((uint16_t *)&packet.ip, sizeof(packet.ip))) {
|
|
log1("bad IP header checksum, ignoring");
|
|
return -2;
|
|
}
|
|
|
|
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
|
|
if (cmsg->cmsg_level == SOL_PACKET
|
|
&& cmsg->cmsg_type == PACKET_AUXDATA
|
|
) {
|
|
/* some VMs don't checksum UDP and TCP data
|
|
* they send to the same physical machine,
|
|
* here we detect this case:
|
|
*/
|
|
struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
|
|
if (aux->tp_status & TP_STATUS_CSUMNOTREADY)
|
|
goto skip_udp_sum_check;
|
|
}
|
|
}
|
|
|
|
/* verify UDP checksum. IP header has to be modified for this */
|
|
memset(&packet.ip, 0, offsetof(struct iphdr, protocol));
|
|
/* ip.xx fields which are not memset: protocol, check, saddr, daddr */
|
|
packet.ip.tot_len = packet.udp.len; /* yes, this is needed */
|
|
check = packet.udp.check;
|
|
packet.udp.check = 0;
|
|
if (check && check != inet_cksum((uint16_t *)&packet, bytes)) {
|
|
log1("packet with bad UDP checksum received, ignoring");
|
|
return -2;
|
|
}
|
|
skip_udp_sum_check:
|
|
|
|
if (packet.data.cookie != htonl(DHCP_MAGIC)) {
|
|
bb_error_msg("packet with bad magic, ignoring");
|
|
return -2;
|
|
}
|
|
|
|
log1("received %s", "a packet");
|
|
udhcp_dump_packet(&packet.data);
|
|
|
|
bytes -= sizeof(packet.ip) + sizeof(packet.udp);
|
|
memcpy(dhcp_pkt, &packet.data, bytes);
|
|
return bytes;
|
|
}
|
|
|
|
|
|
/*** Main ***/
|
|
|
|
static int sockfd = -1;
|
|
|
|
#define LISTEN_NONE 0
|
|
#define LISTEN_KERNEL 1
|
|
#define LISTEN_RAW 2
|
|
static smallint listen_mode;
|
|
|
|
/* initial state: (re)start DHCP negotiation */
|
|
#define INIT_SELECTING 0
|
|
/* discover was sent, DHCPOFFER reply received */
|
|
#define REQUESTING 1
|
|
/* select/renew was sent, DHCPACK reply received */
|
|
#define BOUND 2
|
|
/* half of lease passed, want to renew it by sending unicast renew requests */
|
|
#define RENEWING 3
|
|
/* renew requests were not answered, lease is almost over, send broadcast renew */
|
|
#define REBINDING 4
|
|
/* manually requested renew (SIGUSR1) */
|
|
#define RENEW_REQUESTED 5
|
|
/* release, possibly manually requested (SIGUSR2) */
|
|
#define RELEASED 6
|
|
static smallint state;
|
|
|
|
static int udhcp_raw_socket(int ifindex)
|
|
{
|
|
int fd;
|
|
struct sockaddr_ll sock;
|
|
|
|
log1("opening raw socket on ifindex %d", ifindex); //log2?
|
|
|
|
fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
|
|
/* ^^^^^
|
|
* SOCK_DGRAM: remove link-layer headers on input (SOCK_RAW keeps them)
|
|
* ETH_P_IP: want to receive only packets with IPv4 eth type
|
|
*/
|
|
log1("got raw socket fd"); //log2?
|
|
|
|
sock.sll_family = AF_PACKET;
|
|
sock.sll_protocol = htons(ETH_P_IP);
|
|
sock.sll_ifindex = ifindex;
|
|
xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
|
|
|
|
#if 0 /* Several users reported breakage when BPF filter is used */
|
|
if (CLIENT_PORT == 68) {
|
|
/* Use only if standard port is in use */
|
|
/*
|
|
* I've selected not to see LL header, so BPF doesn't see it, too.
|
|
* The filter may also pass non-IP and non-ARP packets, but we do
|
|
* a more complete check when receiving the message in userspace.
|
|
*
|
|
* and filter shamelessly stolen from:
|
|
*
|
|
* http://www.flamewarmaster.de/software/dhcpclient/
|
|
*
|
|
* There are a few other interesting ideas on that page (look under
|
|
* "Motivation"). Use of netlink events is most interesting. Think
|
|
* of various network servers listening for events and reconfiguring.
|
|
* That would obsolete sending HUP signals and/or make use of restarts.
|
|
*
|
|
* Copyright: 2006, 2007 Stefan Rompf <sux@loplof.de>.
|
|
* License: GPL v2.
|
|
*/
|
|
static const struct sock_filter filter_instr[] = {
|
|
/* load 9th byte (protocol) */
|
|
BPF_STMT(BPF_LD|BPF_B|BPF_ABS, 9),
|
|
/* jump to L1 if it is IPPROTO_UDP, else to L4 */
|
|
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, IPPROTO_UDP, 0, 6),
|
|
/* L1: load halfword from offset 6 (flags and frag offset) */
|
|
BPF_STMT(BPF_LD|BPF_H|BPF_ABS, 6),
|
|
/* jump to L4 if any bits in frag offset field are set, else to L2 */
|
|
BPF_JUMP(BPF_JMP|BPF_JSET|BPF_K, 0x1fff, 4, 0),
|
|
/* L2: skip IP header (load index reg with header len) */
|
|
BPF_STMT(BPF_LDX|BPF_B|BPF_MSH, 0),
|
|
/* load udp destination port from halfword[header_len + 2] */
|
|
BPF_STMT(BPF_LD|BPF_H|BPF_IND, 2),
|
|
/* jump to L3 if udp dport is CLIENT_PORT, else to L4 */
|
|
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
|
|
/* L3: accept packet ("accept 0x7fffffff bytes") */
|
|
/* Accepting 0xffffffff works too but kernel 2.6.19 is buggy */
|
|
BPF_STMT(BPF_RET|BPF_K, 0x7fffffff),
|
|
/* L4: discard packet ("accept zero bytes") */
|
|
BPF_STMT(BPF_RET|BPF_K, 0),
|
|
};
|
|
static const struct sock_fprog filter_prog = {
|
|
.len = sizeof(filter_instr) / sizeof(filter_instr[0]),
|
|
/* casting const away: */
|
|
.filter = (struct sock_filter *) filter_instr,
|
|
};
|
|
/* Ignoring error (kernel may lack support for this) */
|
|
if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter_prog,
|
|
sizeof(filter_prog)) >= 0)
|
|
log1("attached filter to raw socket fd"); // log?
|
|
}
|
|
#endif
|
|
|
|
if (setsockopt_1(fd, SOL_PACKET, PACKET_AUXDATA) != 0) {
|
|
if (errno != ENOPROTOOPT)
|
|
log1("can't set PACKET_AUXDATA on raw socket");
|
|
}
|
|
|
|
log1("created raw socket");
|
|
|
|
return fd;
|
|
}
|
|
|
|
static void change_listen_mode(int new_mode)
|
|
{
|
|
log1("entering listen mode: %s",
|
|
new_mode != LISTEN_NONE
|
|
? (new_mode == LISTEN_KERNEL ? "kernel" : "raw")
|
|
: "none"
|
|
);
|
|
|
|
listen_mode = new_mode;
|
|
if (sockfd >= 0) {
|
|
close(sockfd);
|
|
sockfd = -1;
|
|
}
|
|
if (new_mode == LISTEN_KERNEL)
|
|
sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
|
|
else if (new_mode != LISTEN_NONE)
|
|
sockfd = udhcp_raw_socket(client_config.ifindex);
|
|
/* else LISTEN_NONE: sockfd stays closed */
|
|
}
|
|
|
|
/* Called only on SIGUSR1 */
|
|
static void perform_renew(void)
|
|
{
|
|
bb_error_msg("performing DHCP renew");
|
|
switch (state) {
|
|
case BOUND:
|
|
change_listen_mode(LISTEN_KERNEL);
|
|
case RENEWING:
|
|
case REBINDING:
|
|
state = RENEW_REQUESTED;
|
|
break;
|
|
case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
|
|
udhcp_run_script(NULL, "deconfig");
|
|
case REQUESTING:
|
|
case RELEASED:
|
|
change_listen_mode(LISTEN_RAW);
|
|
state = INIT_SELECTING;
|
|
break;
|
|
case INIT_SELECTING:
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void perform_release(uint32_t server_addr, uint32_t requested_ip)
|
|
{
|
|
char buffer[sizeof("255.255.255.255")];
|
|
struct in_addr temp_addr;
|
|
|
|
/* send release packet */
|
|
if (state == BOUND
|
|
|| state == RENEWING
|
|
|| state == REBINDING
|
|
|| state == RENEW_REQUESTED
|
|
) {
|
|
temp_addr.s_addr = server_addr;
|
|
strcpy(buffer, inet_ntoa(temp_addr));
|
|
temp_addr.s_addr = requested_ip;
|
|
bb_error_msg("unicasting a release of %s to %s",
|
|
inet_ntoa(temp_addr), buffer);
|
|
send_release(server_addr, requested_ip); /* unicast */
|
|
}
|
|
bb_error_msg("entering released state");
|
|
/*
|
|
* We can be here on: SIGUSR2,
|
|
* or on exit (SIGTERM) and -R "release on quit" is specified.
|
|
* Users requested to be notified in all cases, even if not in one
|
|
* of the states above.
|
|
*/
|
|
udhcp_run_script(NULL, "deconfig");
|
|
|
|
change_listen_mode(LISTEN_NONE);
|
|
state = RELEASED;
|
|
}
|
|
|
|
static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
|
|
{
|
|
uint8_t *storage;
|
|
int len = strnlen(str, 255);
|
|
storage = xzalloc(len + extra + OPT_DATA);
|
|
storage[OPT_CODE] = code;
|
|
storage[OPT_LEN] = len + extra;
|
|
memcpy(storage + extra + OPT_DATA, str, len);
|
|
return storage;
|
|
}
|
|
|
|
#if BB_MMU
|
|
static void client_background(void)
|
|
{
|
|
bb_daemonize(0);
|
|
logmode &= ~LOGMODE_STDIO;
|
|
/* rewrite pidfile, as our pid is different now */
|
|
write_pidfile(client_config.pidfile);
|
|
}
|
|
#endif
|
|
|
|
//usage:#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
|
|
//usage:# define IF_UDHCP_VERBOSE(...) __VA_ARGS__
|
|
//usage:#else
|
|
//usage:# define IF_UDHCP_VERBOSE(...)
|
|
//usage:#endif
|
|
//usage:#define udhcpc_trivial_usage
|
|
//usage: "[-fbq"IF_UDHCP_VERBOSE("v")"RB]"IF_FEATURE_UDHCPC_ARPING(" [-a[MSEC]]")" [-t N] [-T SEC] [-A SEC/-n]\n"
|
|
//usage: " [-i IFACE]"IF_FEATURE_UDHCP_PORT(" [-P PORT]")" [-s PROG] [-p PIDFILE]\n"
|
|
//usage: " [-oC] [-r IP] [-V VENDOR] [-F NAME] [-x OPT:VAL]... [-O OPT]..."
|
|
//usage:#define udhcpc_full_usage "\n"
|
|
//usage: IF_LONG_OPTS(
|
|
//usage: "\n -i,--interface IFACE Interface to use (default eth0)"
|
|
//usage: IF_FEATURE_UDHCP_PORT(
|
|
//usage: "\n -P,--client-port PORT Use PORT (default 68)"
|
|
//usage: )
|
|
//usage: "\n -s,--script PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
|
|
//usage: "\n -p,--pidfile FILE Create pidfile"
|
|
//usage: "\n -B,--broadcast Request broadcast replies"
|
|
//usage: "\n -t,--retries N Send up to N discover packets (default 3)"
|
|
//usage: "\n -T,--timeout SEC Pause between packets (default 3)"
|
|
//usage: "\n -A,--tryagain SEC Wait if lease is not obtained (default 20)"
|
|
//usage: "\n -n,--now Exit if lease is not obtained"
|
|
//usage: "\n -q,--quit Exit after obtaining lease"
|
|
//usage: "\n -R,--release Release IP on exit"
|
|
//usage: "\n -f,--foreground Run in foreground"
|
|
//usage: USE_FOR_MMU(
|
|
//usage: "\n -b,--background Background if lease is not obtained"
|
|
//usage: )
|
|
//usage: "\n -S,--syslog Log to syslog too"
|
|
//usage: IF_FEATURE_UDHCPC_ARPING(
|
|
//usage: "\n -a[MSEC],--arping[=MSEC] Validate offered address with ARP ping"
|
|
//usage: )
|
|
//usage: "\n -r,--request IP Request this IP address"
|
|
//usage: "\n -o,--no-default-options Don't request any options (unless -O is given)"
|
|
//usage: "\n -O,--request-option OPT Request option OPT from server (cumulative)"
|
|
//usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
|
|
//usage: "\n Examples of string, numeric, and hex byte opts:"
|
|
//usage: "\n -x hostname:bbox - option 12"
|
|
//usage: "\n -x lease:3600 - option 51 (lease time)"
|
|
//usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
|
|
//usage: "\n -F,--fqdn NAME Ask server to update DNS mapping for NAME"
|
|
//usage: "\n -V,--vendorclass VENDOR Vendor identifier (default 'udhcp VERSION')"
|
|
//usage: "\n -C,--clientid-none Don't send MAC as client identifier"
|
|
//usage: IF_UDHCP_VERBOSE(
|
|
//usage: "\n -v Verbose"
|
|
//usage: )
|
|
//usage: )
|
|
//usage: IF_NOT_LONG_OPTS(
|
|
//usage: "\n -i IFACE Interface to use (default eth0)"
|
|
//usage: IF_FEATURE_UDHCP_PORT(
|
|
//usage: "\n -P PORT Use PORT (default 68)"
|
|
//usage: )
|
|
//usage: "\n -s PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
|
|
//usage: "\n -p FILE Create pidfile"
|
|
//usage: "\n -B Request broadcast replies"
|
|
//usage: "\n -t N Send up to N discover packets (default 3)"
|
|
//usage: "\n -T SEC Pause between packets (default 3)"
|
|
//usage: "\n -A SEC Wait if lease is not obtained (default 20)"
|
|
//usage: "\n -n Exit if lease is not obtained"
|
|
//usage: "\n -q Exit after obtaining lease"
|
|
//usage: "\n -R Release IP on exit"
|
|
//usage: "\n -f Run in foreground"
|
|
//usage: USE_FOR_MMU(
|
|
//usage: "\n -b Background if lease is not obtained"
|
|
//usage: )
|
|
//usage: "\n -S Log to syslog too"
|
|
//usage: IF_FEATURE_UDHCPC_ARPING(
|
|
//usage: "\n -a[MSEC] Validate offered address with ARP ping"
|
|
//usage: )
|
|
//usage: "\n -r IP Request this IP address"
|
|
//usage: "\n -o Don't request any options (unless -O is given)"
|
|
//usage: "\n -O OPT Request option OPT from server (cumulative)"
|
|
//usage: "\n -x OPT:VAL Include option OPT in sent packets (cumulative)"
|
|
//usage: "\n Examples of string, numeric, and hex byte opts:"
|
|
//usage: "\n -x hostname:bbox - option 12"
|
|
//usage: "\n -x lease:3600 - option 51 (lease time)"
|
|
//usage: "\n -x 0x3d:0100BEEFC0FFEE - option 61 (client id)"
|
|
//usage: "\n -F NAME Ask server to update DNS mapping for NAME"
|
|
//usage: "\n -V VENDOR Vendor identifier (default 'udhcp VERSION')"
|
|
//usage: "\n -C Don't send MAC as client identifier"
|
|
//usage: IF_UDHCP_VERBOSE(
|
|
//usage: "\n -v Verbose"
|
|
//usage: )
|
|
//usage: )
|
|
//usage: "\nSignals:"
|
|
//usage: "\n USR1 Renew lease"
|
|
//usage: "\n USR2 Release lease"
|
|
|
|
|
|
int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
|
|
int udhcpc_main(int argc UNUSED_PARAM, char **argv)
|
|
{
|
|
uint8_t *message;
|
|
const char *str_V, *str_h, *str_F, *str_r;
|
|
IF_FEATURE_UDHCPC_ARPING(const char *str_a = "2000";)
|
|
IF_FEATURE_UDHCP_PORT(char *str_P;)
|
|
void *clientid_mac_ptr;
|
|
llist_t *list_O = NULL;
|
|
llist_t *list_x = NULL;
|
|
int tryagain_timeout = 20;
|
|
int discover_timeout = 3;
|
|
int discover_retries = 3;
|
|
uint32_t server_addr = server_addr; /* for compiler */
|
|
uint32_t requested_ip = 0;
|
|
uint32_t xid = xid; /* for compiler */
|
|
int packet_num;
|
|
int timeout; /* must be signed */
|
|
unsigned already_waited_sec;
|
|
unsigned opt;
|
|
IF_FEATURE_UDHCPC_ARPING(unsigned arpping_ms;)
|
|
int retval;
|
|
|
|
setup_common_bufsiz();
|
|
|
|
/* Default options */
|
|
IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
|
|
IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
|
|
client_config.interface = "eth0";
|
|
client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
|
|
str_V = "udhcp "BB_VER;
|
|
|
|
/* Parse command line */
|
|
/* O,x: list; -T,-t,-A take numeric param */
|
|
IF_UDHCP_VERBOSE(opt_complementary = "vv";)
|
|
IF_LONG_OPTS(applet_long_options = udhcpc_longopts;)
|
|
opt = getopt32(argv, "CV:H:h:F:i:np:qRr:s:T:+t:+SA:+O:*ox:*fB"
|
|
USE_FOR_MMU("b")
|
|
IF_FEATURE_UDHCPC_ARPING("a::")
|
|
IF_FEATURE_UDHCP_PORT("P:")
|
|
"v"
|
|
, &str_V, &str_h, &str_h, &str_F
|
|
, &client_config.interface, &client_config.pidfile, &str_r /* i,p */
|
|
, &client_config.script /* s */
|
|
, &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
|
|
, &list_O
|
|
, &list_x
|
|
IF_FEATURE_UDHCPC_ARPING(, &str_a)
|
|
IF_FEATURE_UDHCP_PORT(, &str_P)
|
|
IF_UDHCP_VERBOSE(, &dhcp_verbose)
|
|
);
|
|
if (opt & (OPT_h|OPT_H)) {
|
|
//msg added 2011-11
|
|
bb_error_msg("option -h NAME is deprecated, use -x hostname:NAME");
|
|
client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
|
|
}
|
|
if (opt & OPT_F) {
|
|
/* FQDN option format: [0x51][len][flags][0][0]<fqdn> */
|
|
client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
|
|
/* Flag bits: 0000NEOS
|
|
* S: 1 = Client requests server to update A RR in DNS as well as PTR
|
|
* O: 1 = Server indicates to client that DNS has been updated regardless
|
|
* E: 1 = Name is in DNS format, i.e. <4>host<6>domain<3>com<0>,
|
|
* not "host.domain.com". Format 0 is obsolete.
|
|
* N: 1 = Client requests server to not update DNS (S must be 0 then)
|
|
* Two [0] bytes which follow are deprecated and must be 0.
|
|
*/
|
|
client_config.fqdn[OPT_DATA + 0] = 0x1;
|
|
/*client_config.fqdn[OPT_DATA + 1] = 0; - xzalloc did it */
|
|
/*client_config.fqdn[OPT_DATA + 2] = 0; */
|
|
}
|
|
if (opt & OPT_r)
|
|
requested_ip = inet_addr(str_r);
|
|
#if ENABLE_FEATURE_UDHCP_PORT
|
|
if (opt & OPT_P) {
|
|
CLIENT_PORT = xatou16(str_P);
|
|
SERVER_PORT = CLIENT_PORT - 1;
|
|
}
|
|
#endif
|
|
IF_FEATURE_UDHCPC_ARPING(arpping_ms = xatou(str_a);)
|
|
while (list_O) {
|
|
char *optstr = llist_pop(&list_O);
|
|
unsigned n = bb_strtou(optstr, NULL, 0);
|
|
if (errno || n > 254) {
|
|
n = udhcp_option_idx(optstr);
|
|
n = dhcp_optflags[n].code;
|
|
}
|
|
client_config.opt_mask[n >> 3] |= 1 << (n & 7);
|
|
}
|
|
if (!(opt & OPT_o)) {
|
|
unsigned i, n;
|
|
for (i = 0; (n = dhcp_optflags[i].code) != 0; i++) {
|
|
if (dhcp_optflags[i].flags & OPTION_REQ) {
|
|
client_config.opt_mask[n >> 3] |= 1 << (n & 7);
|
|
}
|
|
}
|
|
}
|
|
while (list_x) {
|
|
char *optstr = llist_pop(&list_x);
|
|
char *colon = strchr(optstr, ':');
|
|
if (colon)
|
|
*colon = ' ';
|
|
/* now it looks similar to udhcpd's config file line:
|
|
* "optname optval", using the common routine: */
|
|
udhcp_str2optset(optstr, &client_config.options);
|
|
}
|
|
|
|
if (udhcp_read_interface(client_config.interface,
|
|
&client_config.ifindex,
|
|
NULL,
|
|
client_config.client_mac)
|
|
) {
|
|
return 1;
|
|
}
|
|
|
|
clientid_mac_ptr = NULL;
|
|
if (!(opt & OPT_C) && !udhcp_find_option(client_config.options, DHCP_CLIENT_ID)) {
|
|
/* not suppressed and not set, set the default client ID */
|
|
client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
|
|
client_config.clientid[OPT_DATA] = 1; /* type: ethernet */
|
|
clientid_mac_ptr = client_config.clientid + OPT_DATA+1;
|
|
memcpy(clientid_mac_ptr, client_config.client_mac, 6);
|
|
}
|
|
if (str_V[0] != '\0') {
|
|
// can drop -V, str_V, client_config.vendorclass,
|
|
// but need to add "vendor" to the list of recognized
|
|
// string opts for this to work;
|
|
// and need to tweak add_client_options() too...
|
|
// ...so the question is, should we?
|
|
//bb_error_msg("option -V VENDOR is deprecated, use -x vendor:VENDOR");
|
|
client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
|
|
}
|
|
|
|
#if !BB_MMU
|
|
/* on NOMMU reexec (i.e., background) early */
|
|
if (!(opt & OPT_f)) {
|
|
bb_daemonize_or_rexec(0 /* flags */, argv);
|
|
logmode = LOGMODE_NONE;
|
|
}
|
|
#endif
|
|
if (opt & OPT_S) {
|
|
openlog(applet_name, LOG_PID, LOG_DAEMON);
|
|
logmode |= LOGMODE_SYSLOG;
|
|
}
|
|
|
|
/* Make sure fd 0,1,2 are open */
|
|
bb_sanitize_stdio();
|
|
/* Equivalent of doing a fflush after every \n */
|
|
setlinebuf(stdout);
|
|
/* Create pidfile */
|
|
write_pidfile(client_config.pidfile);
|
|
/* Goes to stdout (unless NOMMU) and possibly syslog */
|
|
bb_error_msg("started, v"BB_VER);
|
|
/* Set up the signal pipe */
|
|
udhcp_sp_setup();
|
|
/* We want random_xid to be random... */
|
|
srand(monotonic_us());
|
|
|
|
state = INIT_SELECTING;
|
|
udhcp_run_script(NULL, "deconfig");
|
|
change_listen_mode(LISTEN_RAW);
|
|
packet_num = 0;
|
|
timeout = 0;
|
|
already_waited_sec = 0;
|
|
|
|
/* Main event loop. select() waits on signal pipe and possibly
|
|
* on sockfd.
|
|
* "continue" statements in code below jump to the top of the loop.
|
|
*/
|
|
for (;;) {
|
|
int tv;
|
|
struct pollfd pfds[2];
|
|
struct dhcp_packet packet;
|
|
/* silence "uninitialized!" warning */
|
|
unsigned timestamp_before_wait = timestamp_before_wait;
|
|
|
|
//bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
|
|
|
|
/* Was opening raw or udp socket here
|
|
* if (listen_mode != LISTEN_NONE && sockfd < 0),
|
|
* but on fast network renew responses return faster
|
|
* than we open sockets. Thus this code is moved
|
|
* to change_listen_mode(). Thus we open listen socket
|
|
* BEFORE we send renew request (see "case BOUND:"). */
|
|
|
|
udhcp_sp_fd_set(pfds, sockfd);
|
|
|
|
tv = timeout - already_waited_sec;
|
|
retval = 0;
|
|
/* If we already timed out, fall through with retval = 0, else... */
|
|
if (tv > 0) {
|
|
log1("waiting on select %u seconds", tv);
|
|
timestamp_before_wait = (unsigned)monotonic_sec();
|
|
retval = poll(pfds, 2, tv * 1000);
|
|
if (retval < 0) {
|
|
/* EINTR? A signal was caught, don't panic */
|
|
if (errno == EINTR) {
|
|
already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
|
|
continue;
|
|
}
|
|
/* Else: an error occured, panic! */
|
|
bb_perror_msg_and_die("select");
|
|
}
|
|
}
|
|
|
|
/* If timeout dropped to zero, time to become active:
|
|
* resend discover/renew/whatever
|
|
*/
|
|
if (retval == 0) {
|
|
/* When running on a bridge, the ifindex may have changed
|
|
* (e.g. if member interfaces were added/removed
|
|
* or if the status of the bridge changed).
|
|
* Refresh ifindex and client_mac:
|
|
*/
|
|
if (udhcp_read_interface(client_config.interface,
|
|
&client_config.ifindex,
|
|
NULL,
|
|
client_config.client_mac)
|
|
) {
|
|
goto ret0; /* iface is gone? */
|
|
}
|
|
if (clientid_mac_ptr)
|
|
memcpy(clientid_mac_ptr, client_config.client_mac, 6);
|
|
|
|
/* We will restart the wait in any case */
|
|
already_waited_sec = 0;
|
|
|
|
switch (state) {
|
|
case INIT_SELECTING:
|
|
if (!discover_retries || packet_num < discover_retries) {
|
|
if (packet_num == 0)
|
|
xid = random_xid();
|
|
/* broadcast */
|
|
send_discover(xid, requested_ip);
|
|
timeout = discover_timeout;
|
|
packet_num++;
|
|
continue;
|
|
}
|
|
leasefail:
|
|
udhcp_run_script(NULL, "leasefail");
|
|
#if BB_MMU /* -b is not supported on NOMMU */
|
|
if (opt & OPT_b) { /* background if no lease */
|
|
bb_error_msg("no lease, forking to background");
|
|
client_background();
|
|
/* do not background again! */
|
|
opt = ((opt & ~OPT_b) | OPT_f);
|
|
} else
|
|
#endif
|
|
if (opt & OPT_n) { /* abort if no lease */
|
|
bb_error_msg("no lease, failing");
|
|
retval = 1;
|
|
goto ret;
|
|
}
|
|
/* wait before trying again */
|
|
timeout = tryagain_timeout;
|
|
packet_num = 0;
|
|
continue;
|
|
case REQUESTING:
|
|
if (packet_num < 3) {
|
|
/* send broadcast select packet */
|
|
send_select(xid, server_addr, requested_ip);
|
|
timeout = discover_timeout;
|
|
packet_num++;
|
|
continue;
|
|
}
|
|
/* Timed out, go back to init state.
|
|
* "discover...select...discover..." loops
|
|
* were seen in the wild. Treat them similarly
|
|
* to "no response to discover" case */
|
|
change_listen_mode(LISTEN_RAW);
|
|
state = INIT_SELECTING;
|
|
goto leasefail;
|
|
case BOUND:
|
|
/* 1/2 lease passed, enter renewing state */
|
|
state = RENEWING;
|
|
client_config.first_secs = 0; /* make secs field count from 0 */
|
|
change_listen_mode(LISTEN_KERNEL);
|
|
log1("entering renew state");
|
|
/* fall right through */
|
|
case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
|
|
case_RENEW_REQUESTED:
|
|
case RENEWING:
|
|
if (timeout > 60) {
|
|
/* send an unicast renew request */
|
|
/* Sometimes observed to fail (EADDRNOTAVAIL) to bind
|
|
* a new UDP socket for sending inside send_renew.
|
|
* I hazard to guess existing listening socket
|
|
* is somehow conflicting with it, but why is it
|
|
* not deterministic then?! Strange.
|
|
* Anyway, it does recover by eventually failing through
|
|
* into INIT_SELECTING state.
|
|
*/
|
|
send_renew(xid, server_addr, requested_ip);
|
|
timeout >>= 1;
|
|
continue;
|
|
}
|
|
/* Timed out, enter rebinding state */
|
|
log1("entering rebinding state");
|
|
state = REBINDING;
|
|
/* fall right through */
|
|
case REBINDING:
|
|
/* Switch to bcast receive */
|
|
change_listen_mode(LISTEN_RAW);
|
|
/* Lease is *really* about to run out,
|
|
* try to find DHCP server using broadcast */
|
|
if (timeout > 0) {
|
|
/* send a broadcast renew request */
|
|
send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
|
|
timeout >>= 1;
|
|
continue;
|
|
}
|
|
/* Timed out, enter init state */
|
|
bb_error_msg("lease lost, entering init state");
|
|
udhcp_run_script(NULL, "deconfig");
|
|
state = INIT_SELECTING;
|
|
client_config.first_secs = 0; /* make secs field count from 0 */
|
|
/*timeout = 0; - already is */
|
|
packet_num = 0;
|
|
continue;
|
|
/* case RELEASED: */
|
|
}
|
|
/* yah, I know, *you* say it would never happen */
|
|
timeout = INT_MAX;
|
|
continue; /* back to main loop */
|
|
} /* if select timed out */
|
|
|
|
/* select() didn't timeout, something happened */
|
|
|
|
/* Is it a signal? */
|
|
/* note: udhcp_sp_read checks poll result before reading */
|
|
switch (udhcp_sp_read(pfds)) {
|
|
case SIGUSR1:
|
|
client_config.first_secs = 0; /* make secs field count from 0 */
|
|
already_waited_sec = 0;
|
|
perform_renew();
|
|
if (state == RENEW_REQUESTED) {
|
|
/* We might be either on the same network
|
|
* (in which case renew might work),
|
|
* or we might be on a completely different one
|
|
* (in which case renew won't ever succeed).
|
|
* For the second case, must make sure timeout
|
|
* is not too big, or else we can send
|
|
* futile renew requests for hours.
|
|
* (Ab)use -A TIMEOUT value (usually 20 sec)
|
|
* as a cap on the timeout.
|
|
*/
|
|
if (timeout > tryagain_timeout)
|
|
timeout = tryagain_timeout;
|
|
goto case_RENEW_REQUESTED;
|
|
}
|
|
/* Start things over */
|
|
packet_num = 0;
|
|
/* Kill any timeouts, user wants this to hurry along */
|
|
timeout = 0;
|
|
continue;
|
|
case SIGUSR2:
|
|
perform_release(server_addr, requested_ip);
|
|
timeout = INT_MAX;
|
|
continue;
|
|
case SIGTERM:
|
|
bb_error_msg("received %s", "SIGTERM");
|
|
goto ret0;
|
|
}
|
|
|
|
/* Is it a packet? */
|
|
if (listen_mode == LISTEN_NONE || !pfds[1].revents)
|
|
continue; /* no */
|
|
|
|
{
|
|
int len;
|
|
|
|
/* A packet is ready, read it */
|
|
if (listen_mode == LISTEN_KERNEL)
|
|
len = udhcp_recv_kernel_packet(&packet, sockfd);
|
|
else
|
|
len = udhcp_recv_raw_packet(&packet, sockfd);
|
|
if (len == -1) {
|
|
/* Error is severe, reopen socket */
|
|
bb_error_msg("read error: %s, reopening socket", strerror(errno));
|
|
sleep(discover_timeout); /* 3 seconds by default */
|
|
change_listen_mode(listen_mode); /* just close and reopen */
|
|
}
|
|
/* If this packet will turn out to be unrelated/bogus,
|
|
* we will go back and wait for next one.
|
|
* Be sure timeout is properly decreased. */
|
|
already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
|
|
if (len < 0)
|
|
continue;
|
|
}
|
|
|
|
if (packet.xid != xid) {
|
|
log1("xid %x (our is %x), ignoring packet",
|
|
(unsigned)packet.xid, (unsigned)xid);
|
|
continue;
|
|
}
|
|
|
|
/* Ignore packets that aren't for us */
|
|
if (packet.hlen != 6
|
|
|| memcmp(packet.chaddr, client_config.client_mac, 6) != 0
|
|
) {
|
|
//FIXME: need to also check that last 10 bytes are zero
|
|
log1("chaddr does not match, ignoring packet"); // log2?
|
|
continue;
|
|
}
|
|
|
|
message = udhcp_get_option(&packet, DHCP_MESSAGE_TYPE);
|
|
if (message == NULL) {
|
|
bb_error_msg("no message type option, ignoring packet");
|
|
continue;
|
|
}
|
|
|
|
switch (state) {
|
|
case INIT_SELECTING:
|
|
/* Must be a DHCPOFFER */
|
|
if (*message == DHCPOFFER) {
|
|
uint8_t *temp;
|
|
|
|
/* What exactly is server's IP? There are several values.
|
|
* Example DHCP offer captured with tchdump:
|
|
*
|
|
* 10.34.25.254:67 > 10.34.25.202:68 // IP header's src
|
|
* BOOTP fields:
|
|
* Your-IP 10.34.25.202
|
|
* Server-IP 10.34.32.125 // "next server" IP
|
|
* Gateway-IP 10.34.25.254 // relay's address (if DHCP relays are in use)
|
|
* DHCP options:
|
|
* DHCP-Message Option 53, length 1: Offer
|
|
* Server-ID Option 54, length 4: 10.34.255.7 // "server ID"
|
|
* Default-Gateway Option 3, length 4: 10.34.25.254 // router
|
|
*
|
|
* We think that real server IP (one to use in renew/release)
|
|
* is one in Server-ID option. But I am not 100% sure.
|
|
* IP header's src and Gateway-IP (same in this example)
|
|
* might work too.
|
|
* "Next server" and router are definitely wrong ones to use, though...
|
|
*/
|
|
/* We used to ignore pcakets without DHCP_SERVER_ID.
|
|
* I've got user reports from people who run "address-less" servers.
|
|
* They either supply DHCP_SERVER_ID of 0.0.0.0 or don't supply it at all.
|
|
* They say ISC DHCP client supports this case.
|
|
*/
|
|
server_addr = 0;
|
|
temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
|
|
if (!temp) {
|
|
bb_error_msg("no server ID, using 0.0.0.0");
|
|
} else {
|
|
/* it IS unaligned sometimes, don't "optimize" */
|
|
move_from_unaligned32(server_addr, temp);
|
|
}
|
|
/*xid = packet.xid; - already is */
|
|
requested_ip = packet.yiaddr;
|
|
|
|
/* enter requesting state */
|
|
state = REQUESTING;
|
|
timeout = 0;
|
|
packet_num = 0;
|
|
already_waited_sec = 0;
|
|
}
|
|
continue;
|
|
case REQUESTING:
|
|
case RENEWING:
|
|
case RENEW_REQUESTED:
|
|
case REBINDING:
|
|
if (*message == DHCPACK) {
|
|
unsigned start;
|
|
uint32_t lease_seconds;
|
|
struct in_addr temp_addr;
|
|
uint8_t *temp;
|
|
|
|
temp = udhcp_get_option(&packet, DHCP_LEASE_TIME);
|
|
if (!temp) {
|
|
bb_error_msg("no lease time with ACK, using 1 hour lease");
|
|
lease_seconds = 60 * 60;
|
|
} else {
|
|
/* it IS unaligned sometimes, don't "optimize" */
|
|
move_from_unaligned32(lease_seconds, temp);
|
|
lease_seconds = ntohl(lease_seconds);
|
|
/* paranoia: must not be too small and not prone to overflows */
|
|
if (lease_seconds < 0x10)
|
|
lease_seconds = 0x10;
|
|
if (lease_seconds > 0x7fffffff / 1000)
|
|
lease_seconds = 0x7fffffff / 1000;
|
|
}
|
|
#if ENABLE_FEATURE_UDHCPC_ARPING
|
|
if (opt & OPT_a) {
|
|
/* RFC 2131 3.1 paragraph 5:
|
|
* "The client receives the DHCPACK message with configuration
|
|
* parameters. The client SHOULD perform a final check on the
|
|
* parameters (e.g., ARP for allocated network address), and notes
|
|
* the duration of the lease specified in the DHCPACK message. At this
|
|
* point, the client is configured. If the client detects that the
|
|
* address is already in use (e.g., through the use of ARP),
|
|
* the client MUST send a DHCPDECLINE message to the server and restarts
|
|
* the configuration process..." */
|
|
if (!arpping(packet.yiaddr,
|
|
NULL,
|
|
(uint32_t) 0,
|
|
client_config.client_mac,
|
|
client_config.interface,
|
|
arpping_ms)
|
|
) {
|
|
bb_error_msg("offered address is in use "
|
|
"(got ARP reply), declining");
|
|
send_decline(/*xid,*/ server_addr, packet.yiaddr);
|
|
|
|
if (state != REQUESTING)
|
|
udhcp_run_script(NULL, "deconfig");
|
|
change_listen_mode(LISTEN_RAW);
|
|
state = INIT_SELECTING;
|
|
client_config.first_secs = 0; /* make secs field count from 0 */
|
|
requested_ip = 0;
|
|
timeout = tryagain_timeout;
|
|
packet_num = 0;
|
|
already_waited_sec = 0;
|
|
continue; /* back to main loop */
|
|
}
|
|
}
|
|
#endif
|
|
/* enter bound state */
|
|
temp_addr.s_addr = packet.yiaddr;
|
|
bb_error_msg("lease of %s obtained, lease time %u",
|
|
inet_ntoa(temp_addr), (unsigned)lease_seconds);
|
|
requested_ip = packet.yiaddr;
|
|
|
|
start = monotonic_sec();
|
|
udhcp_run_script(&packet, state == REQUESTING ? "bound" : "renew");
|
|
already_waited_sec = (unsigned)monotonic_sec() - start;
|
|
timeout = lease_seconds / 2;
|
|
if ((unsigned)timeout < already_waited_sec) {
|
|
/* Something went wrong. Back to discover state */
|
|
timeout = already_waited_sec = 0;
|
|
}
|
|
|
|
state = BOUND;
|
|
change_listen_mode(LISTEN_NONE);
|
|
if (opt & OPT_q) { /* quit after lease */
|
|
goto ret0;
|
|
}
|
|
/* future renew failures should not exit (JM) */
|
|
opt &= ~OPT_n;
|
|
#if BB_MMU /* NOMMU case backgrounded earlier */
|
|
if (!(opt & OPT_f)) {
|
|
client_background();
|
|
/* do not background again! */
|
|
opt = ((opt & ~OPT_b) | OPT_f);
|
|
}
|
|
#endif
|
|
/* make future renew packets use different xid */
|
|
/* xid = random_xid(); ...but why bother? */
|
|
|
|
continue; /* back to main loop */
|
|
}
|
|
if (*message == DHCPNAK) {
|
|
/* If network has more than one DHCP server,
|
|
* "wrong" server can reply first, with a NAK.
|
|
* Do not interpret it as a NAK from "our" server.
|
|
*/
|
|
if (server_addr != 0) {
|
|
uint32_t svid;
|
|
uint8_t *temp;
|
|
|
|
temp = udhcp_get_option(&packet, DHCP_SERVER_ID);
|
|
if (!temp) {
|
|
non_matching_svid:
|
|
log1("received DHCP NAK with wrong"
|
|
" server ID, ignoring packet");
|
|
continue;
|
|
}
|
|
move_from_unaligned32(svid, temp);
|
|
if (svid != server_addr)
|
|
goto non_matching_svid;
|
|
}
|
|
/* return to init state */
|
|
bb_error_msg("received %s", "DHCP NAK");
|
|
udhcp_run_script(&packet, "nak");
|
|
if (state != REQUESTING)
|
|
udhcp_run_script(NULL, "deconfig");
|
|
change_listen_mode(LISTEN_RAW);
|
|
sleep(3); /* avoid excessive network traffic */
|
|
state = INIT_SELECTING;
|
|
client_config.first_secs = 0; /* make secs field count from 0 */
|
|
requested_ip = 0;
|
|
timeout = 0;
|
|
packet_num = 0;
|
|
already_waited_sec = 0;
|
|
}
|
|
continue;
|
|
/* case BOUND: - ignore all packets */
|
|
/* case RELEASED: - ignore all packets */
|
|
}
|
|
/* back to main loop */
|
|
} /* for (;;) - main loop ends */
|
|
|
|
ret0:
|
|
if (opt & OPT_R) /* release on quit */
|
|
perform_release(server_addr, requested_ip);
|
|
retval = 0;
|
|
ret:
|
|
/*if (client_config.pidfile) - remove_pidfile has its own check */
|
|
remove_pidfile(client_config.pidfile);
|
|
return retval;
|
|
}
|