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gerrit.nordix.org / codeaurora / busybox / 565af2322271984edf6eb533f90789e52e311848 / . / networking / udhcp / d6_dhcpc.c
blob: 07a8b11c1575106e33ff720be5a1f1a9a8490a42 [file] [log] [blame]
/* vi: set sw=4 ts=4: */
/*
* DHCPv6 client.
*
* WARNING: THIS CODE IS INCOMPLETE.
*
* Copyright (C) 2011-2017 Denys Vlasenko.
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//config:config UDHCPC6
//config: bool "udhcpc6"
//config: default n # not yet ready
//config: depends on FEATURE_IPV6
//config: help
//config: udhcpc6 is a DHCPv6 client
//config:
//config:config FEATURE_UDHCPC6_RFC3646
//config: bool "Support RFC 3646 (DNS server and search list)"
//config: default y
//config: depends on UDHCPC6
//config: help
//config: List of DNS servers and domain search list can be requested with
//config: "-O dns" and "-O search". If server gives these values,
//config: they will be set in environment variables "dns" and "search".
//config:
//config:config FEATURE_UDHCPC6_RFC4704
//config: bool "Support RFC 4704 (Client FQDN)"
//config: default y
//config: depends on UDHCPC6
//config: help
//config: You can request FQDN to be given by server using "-O fqdn".
//config:
//config:config FEATURE_UDHCPC6_RFC4833
//config: bool "Support RFC 4833 (Timezones)"
//config: default y
//config: depends on UDHCPC6
//config: help
//config: You can request POSIX timezone with "-O tz" and timezone name
//config: with "-O timezone".
//applet:IF_UDHCPC6(APPLET(udhcpc6, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_UDHCPC6) += d6_dhcpc.o d6_packet.o d6_socket.o common.o socket.o signalpipe.o
//kbuild:lib-$(CONFIG_FEATURE_UDHCPC6_RFC3646) += domain_codec.o
//kbuild:lib-$(CONFIG_FEATURE_UDHCPC6_RFC4704) += 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 "d6_common.h"
#include <netinet/if_ether.h>
#include <netpacket/packet.h>
#include <linux/filter.h>
/* "struct client_config_t client_config" is in bb_common_bufsiz1 */
static const struct dhcp_optflag d6_optflags[] = {
#if ENABLE_FEATURE_UDHCPC6_RFC3646
{ OPTION_6RD | OPTION_LIST | OPTION_REQ, D6_OPT_DNS_SERVERS },
{ OPTION_DNS_STRING | OPTION_LIST | OPTION_REQ, D6_OPT_DOMAIN_LIST },
#endif
#if ENABLE_FEATURE_UDHCPC6_RFC4704
{ OPTION_DNS_STRING, D6_OPT_CLIENT_FQDN },
#endif
#if ENABLE_FEATURE_UDHCPC6_RFC4833
{ OPTION_STRING, D6_OPT_TZ_POSIX },
{ OPTION_STRING, D6_OPT_TZ_NAME },
#endif
{ 0, 0 }
};
/* Must match d6_optflags[] order */
static const char d6_option_strings[] ALIGN1 =
#if ENABLE_FEATURE_UDHCPC6_RFC3646
"dns" "\0" /* D6_OPT_DNS_SERVERS */
"search" "\0" /* D6_OPT_DOMAIN_LIST */
#endif
#if ENABLE_FEATURE_UDHCPC6_RFC4704
"fqdn" "\0" /* D6_OPT_CLIENT_FQDN */
#endif
#if ENABLE_FEATURE_UDHCPC6_RFC4833
"tz" "\0" /* D6_OPT_TZ_POSIX */
"timezone" "\0" /* D6_OPT_TZ_NAME */
#endif
"\0";
#if ENABLE_LONG_OPTS
static const char udhcpc6_longopts[] ALIGN1 =
"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"
"requestprefix\0" No_argument "d"
"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"
USE_FOR_MMU(
"background\0" No_argument "b"
)
/// IF_FEATURE_UDHCPC_ARPING("arping\0" No_argument "a")
IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
;
#endif
/* Must match getopt32 option string order */
enum {
OPT_i = 1 << 0,
OPT_n = 1 << 1,
OPT_p = 1 << 2,
OPT_q = 1 << 3,
OPT_R = 1 << 4,
OPT_r = 1 << 5,
OPT_s = 1 << 6,
OPT_T = 1 << 7,
OPT_t = 1 << 8,
OPT_S = 1 << 9,
OPT_A = 1 << 10,
OPT_O = 1 << 11,
OPT_o = 1 << 12,
OPT_x = 1 << 13,
OPT_f = 1 << 14,
OPT_d = 1 << 15,
/* The rest has variable bit positions, need to be clever */
OPTBIT_d = 15,
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,)
};
#if ENABLE_FEATURE_UDHCPC6_RFC4704
static const char opt_fqdn_req[] = {
(D6_OPT_CLIENT_FQDN >> 8), (D6_OPT_CLIENT_FQDN & 0xff),
0, 2, /* optlen */
0, /* flags: */
/* S=0: server SHOULD NOT perform AAAA RR updates */
/* O=0: client MUST set this bit to 0 */
/* N=0: server SHOULD perform updates (PTR RR only in our case, since S=0) */
0 /* empty DNS-encoded name */
};
#endif
/*** Utility functions ***/
static void *d6_find_option(uint8_t *option, uint8_t *option_end, unsigned code)
{
/* "length minus 4" */
int len_m4 = option_end - option - 4;
while (len_m4 >= 0) {
/* Next option's len is too big? */
if (option[3] > len_m4)
return NULL; /* yes. bogus packet! */
/* So far we treat any opts with code >255
* or len >255 as bogus, and stop at once.
* This simplifies big-endian handling.
*/
if (option[0] != 0 || option[2] != 0)
return NULL;
/* Option seems to be valid */
/* Does its code match? */
if (option[1] == code)
return option; /* yes! */
len_m4 -= option[3] + 4;
option += option[3] + 4;
}
return NULL;
}
static void *d6_copy_option(uint8_t *option, uint8_t *option_end, unsigned code)
{
uint8_t *opt = d6_find_option(option, option_end, code);
if (!opt)
return opt;
return xmemdup(opt, opt[3] + 4);
}
/*** Script execution code ***/
static char** new_env(void)
{
client6_data.env_ptr = xrealloc_vector(client6_data.env_ptr, 3, client6_data.env_idx);
return &client6_data.env_ptr[client6_data.env_idx++];
}
/* put all the parameters into the environment */
static void option_to_env(uint8_t *option, uint8_t *option_end)
{
#if ENABLE_FEATURE_UDHCPC6_RFC3646
int addrs, option_offset;
#endif
/* "length minus 4" */
int len_m4 = option_end - option - 4;
while (len_m4 >= 0) {
uint32_t v32;
char ipv6str[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")];
if (option[0] != 0 || option[2] != 0)
break;
/* Check if option-length exceeds size of option */
if (option[3] > len_m4)
break;
switch (option[1]) {
//case D6_OPT_CLIENTID:
//case D6_OPT_SERVERID:
case D6_OPT_IA_NA:
case D6_OPT_IA_PD:
option_to_env(option + 16, option + 4 + option[3]);
break;
//case D6_OPT_IA_TA:
case D6_OPT_IAADDR:
/* 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_IAADDR | option-len |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* | IPv6 address |
* | |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | preferred-lifetime |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | valid-lifetime |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
sprint_nip6(ipv6str, option + 4);
*new_env() = xasprintf("ipv6=%s", ipv6str);
move_from_unaligned32(v32, option + 4 + 16 + 4);
*new_env() = xasprintf("lease=%u", (unsigned)v32);
break;
//case D6_OPT_ORO:
//case D6_OPT_PREFERENCE:
//case D6_OPT_ELAPSED_TIME:
//case D6_OPT_RELAY_MSG:
//case D6_OPT_AUTH:
//case D6_OPT_UNICAST:
//case D6_OPT_STATUS_CODE:
//case D6_OPT_RAPID_COMMIT:
//case D6_OPT_USER_CLASS:
//case D6_OPT_VENDOR_CLASS:
//case D6_OPT_VENDOR_OPTS:
//case D6_OPT_INTERFACE_ID:
//case D6_OPT_RECONF_MSG:
//case D6_OPT_RECONF_ACCEPT:
case D6_OPT_IAPREFIX:
/* 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_IAPREFIX | option-length |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | preferred-lifetime |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | valid-lifetime |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | prefix-length | |
* +-+-+-+-+-+-+-+-+ IPv6 prefix |
* | (16 octets) |
* | |
* | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* +-+-+-+-+-+-+-+-+
*/
move_from_unaligned32(v32, option + 4 + 4);
*new_env() = xasprintf("ipv6prefix_lease=%u", (unsigned)v32);
sprint_nip6(ipv6str, option + 4 + 4 + 4 + 1);
*new_env() = xasprintf("ipv6prefix=%s/%u", ipv6str, (unsigned)(option[4 + 4 + 4]));
break;
#if ENABLE_FEATURE_UDHCPC6_RFC3646
case D6_OPT_DNS_SERVERS: {
char *dlist;
/* Make sure payload-size is a multiple of 16 */
if ((option[3] & 0x0f) != 0)
break;
/* Get the number of addresses on the option */
addrs = option[3] >> 4;
/* Setup environment variable */
*new_env() = dlist = xmalloc(4 + addrs * 40 - 1);
dlist = stpcpy(dlist, "dns=");
option_offset = 0;
while (addrs--) {
sprint_nip6(dlist, option + 4 + option_offset);
dlist += 39;
option_offset += 16;
if (addrs)
*dlist++ = ' ';
}
break;
}
case D6_OPT_DOMAIN_LIST: {
char *dlist;
dlist = dname_dec(option + 4, (option[2] << 8) | option[3], "search=");
if (!dlist)
break;
*new_env() = dlist;
break;
}
#endif
#if ENABLE_FEATURE_UDHCPC6_RFC4704
case D6_OPT_CLIENT_FQDN: {
char *dlist;
if (option[3] == 0)
break;
/* Work around broken ISC DHCPD6.
* ISC DHCPD6 does not implement RFC 4704 correctly: It says the first
* byte of option-payload should contain flags where the bits 7-3 are
* reserved for future use and MUST be zero. Instead ISC DHCPD6 just
* writes the entire FQDN as string to option-payload. We assume a
* broken server here if any of the reserved bits are set.
*/
if (option[4] & 0xf8) {
*new_env() = xasprintf("fqdn=%.*s", (int)option[3], (char*)option + 4);
break;
}
dlist = dname_dec(option + 5, (/*(option[2] << 8) |*/ option[3]) - 1, "fqdn=");
if (!dlist)
break;
*new_env() = dlist;
break;
}
#endif
#if ENABLE_FEATURE_UDHCPC6_RFC4833
/* RFC 4833 Timezones */
case D6_OPT_TZ_POSIX:
*new_env() = xasprintf("tz=%.*s", (int)option[3], (char*)option + 4);
break;
case D6_OPT_TZ_NAME:
*new_env() = xasprintf("tz_name=%.*s", (int)option[3], (char*)option + 4);
break;
#endif
}
len_m4 -= 4 + option[3];
option += 4 + option[3];
}
}
static char **fill_envp(struct d6_packet *packet)
{
char **envp, **curr;
client6_data.env_ptr = NULL;
client6_data.env_idx = 0;
*new_env() = xasprintf("interface=%s", client_config.interface);
if (packet)
option_to_env(packet->d6_options, packet->d6_options + sizeof(packet->d6_options));
envp = curr = client6_data.env_ptr;
while (*curr)
putenv(*curr++);
return envp;
}
/* Call a script with a par file and env vars */
static void d6_run_script(struct d6_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)
{
uint32_t t = rand() & htonl(0x00ffffff);
return t;
}
/* Initialize the packet with the proper defaults */
static uint8_t *init_d6_packet(struct d6_packet *packet, char type, uint32_t xid)
{
struct d6_option *clientid;
memset(packet, 0, sizeof(*packet));
packet->d6_xid32 = xid;
packet->d6_msg_type = type;
clientid = (void*)client_config.clientid;
return mempcpy(packet->d6_options, clientid, clientid->len + 2+2);
}
static uint8_t *add_d6_client_options(uint8_t *ptr)
{
uint8_t *start = ptr;
unsigned option;
ptr += 4;
for (option = 1; option < 256; option++) {
if (client_config.opt_mask[option >> 3] & (1 << (option & 7))) {
ptr[0] = (option >> 8);
ptr[1] = option;
ptr += 2;
}
}
if ((ptr - start - 4) != 0) {
start[0] = (D6_OPT_ORO >> 8);
start[1] = D6_OPT_ORO;
start[2] = ((ptr - start - 4) >> 8);
start[3] = (ptr - start - 4);
} else
ptr = start;
#if ENABLE_FEATURE_UDHCPC6_RFC4704
ptr = mempcpy(ptr, &opt_fqdn_req, sizeof(opt_fqdn_req));
#endif
/* Add -x options if any */
//...
return ptr;
}
static int d6_mcast_from_client_config_ifindex(struct d6_packet *packet, uint8_t *end)
{
static const uint8_t FF02__1_2[16] = {
0xFF, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02,
};
return d6_send_raw_packet(
packet, (end - (uint8_t*) packet),
/*src*/ &client6_data.ll_ip6, CLIENT_PORT6,
/*dst*/ (struct in6_addr*)FF02__1_2, SERVER_PORT6, MAC_BCAST_ADDR,
client_config.ifindex
);
}
/* Milticast a DHCPv6 Solicit packet to the network, with an optionally requested IP.
*
* RFC 3315 17.1.1. Creation of Solicit Messages
*
* The client MUST include a Client Identifier option to identify itself
* to the server. The client includes IA options for any IAs to which
* it wants the server to assign addresses. The client MAY include
* addresses in the IAs as a hint to the server about addresses for
* which the client has a preference. ...
*
* The client uses IA_NA options to request the assignment of non-
* temporary addresses and uses IA_TA options to request the assignment
* of temporary addresses. Either IA_NA or IA_TA options, or a
* combination of both, can be included in DHCP messages.
*
* The client SHOULD include an Option Request option (see section 22.7)
* to indicate the options the client is interested in receiving. The
* client MAY additionally include instances of those options that are
* identified in the Option Request option, with data values as hints to
* the server about parameter values the client would like to have
* returned.
*
* The client includes a Reconfigure Accept option (see section 22.20)
* if the client is willing to accept Reconfigure messages from the
* server.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_CLIENTID | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. DUID .
. (variable length) .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_IA_NA | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IAID (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| T1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| T2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. IA_NA-options .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_IAADDR | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| IPv6 address |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| preferred-lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| valid-lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. IAaddr-options .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_ORO | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| requested-option-code-1 | requested-option-code-2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_RECONF_ACCEPT | 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
/* NOINLINE: limit stack usage in caller */
static NOINLINE int send_d6_discover(uint32_t xid, struct in6_addr *requested_ipv6)
{
struct d6_packet packet;
uint8_t *opt_ptr;
unsigned len;
/* Fill in: msg type, client id */
opt_ptr = init_d6_packet(&packet, D6_MSG_SOLICIT, xid);
/* Create new IA_NA, optionally with included IAADDR with requested IP */
free(client6_data.ia_na);
client6_data.ia_na = NULL;
if (option_mask32 & OPT_r) {
len = requested_ipv6 ? 2+2+4+4+4 + 2+2+16+4+4 : 2+2+4+4+4;
client6_data.ia_na = xzalloc(len);
client6_data.ia_na->code = D6_OPT_IA_NA;
client6_data.ia_na->len = len - 4;
*(uint32_t*)client6_data.ia_na->data = rand(); /* IAID */
if (requested_ipv6) {
struct d6_option *iaaddr = (void*)(client6_data.ia_na->data + 4+4+4);
iaaddr->code = D6_OPT_IAADDR;
iaaddr->len = 16+4+4;
memcpy(iaaddr->data, requested_ipv6, 16);
}
opt_ptr = mempcpy(opt_ptr, client6_data.ia_na, len);
}
/* IA_PD */
free(client6_data.ia_pd);
client6_data.ia_pd = NULL;
if (option_mask32 & OPT_d) {
len = 2+2+4+4+4;
client6_data.ia_pd = xzalloc(len);
client6_data.ia_pd->code = D6_OPT_IA_PD;
client6_data.ia_pd->len = len - 4;
*(uint32_t*)client6_data.ia_pd->data = rand(); /* IAID */
opt_ptr = mempcpy(opt_ptr, client6_data.ia_pd, len);
}
/* Add options:
* "param req" option according to -O, options specified with -x
*/
opt_ptr = add_d6_client_options(opt_ptr);
bb_error_msg("sending %s", "discover");
return d6_mcast_from_client_config_ifindex(&packet, opt_ptr);
}
/* Multicast a DHCPv6 request message
*
* RFC 3315 18.1.1. Creation and Transmission of Request Messages
*
* The client uses a Request message to populate IAs with addresses and
* obtain other configuration information. The client includes one or
* more IA options in the Request message. The server then returns
* addresses and other information about the IAs to the client in IA
* options in a Reply message.
*
* The client generates a transaction ID and inserts this value in the
* "transaction-id" field.
*
* The client places the identifier of the destination server in a
* Server Identifier option.
*
* The client MUST include a Client Identifier option to identify itself
* to the server. The client adds any other appropriate options,
* including one or more IA options (if the client is requesting that
* the server assign it some network addresses).
*
* The client MUST include an Option Request option (see section 22.7)
* to indicate the options the client is interested in receiving. The
* client MAY include options with data values as hints to the server
* about parameter values the client would like to have returned.
*
* The client includes a Reconfigure Accept option (see section 22.20)
* indicating whether or not the client is willing to accept Reconfigure
* messages from the server.
*/
/* NOINLINE: limit stack usage in caller */
static NOINLINE int send_d6_select(uint32_t xid)
{
struct d6_packet packet;
uint8_t *opt_ptr;
/* Fill in: msg type, client id */
opt_ptr = init_d6_packet(&packet, D6_MSG_REQUEST, xid);
/* server id */
opt_ptr = mempcpy(opt_ptr, client6_data.server_id, client6_data.server_id->len + 2+2);
/* IA NA (contains requested IP) */
if (client6_data.ia_na)
opt_ptr = mempcpy(opt_ptr, client6_data.ia_na, client6_data.ia_na->len + 2+2);
/* IA PD */
if (client6_data.ia_pd)
opt_ptr = mempcpy(opt_ptr, client6_data.ia_pd, client6_data.ia_pd->len + 2+2);
/* Add options:
* "param req" option according to -O, options specified with -x
*/
opt_ptr = add_d6_client_options(opt_ptr);
bb_error_msg("sending %s", "select");
return d6_mcast_from_client_config_ifindex(&packet, opt_ptr);
}
/* Unicast or broadcast a DHCP renew message
*
* RFC 3315 18.1.3. Creation and Transmission of Renew Messages
*
* To extend the valid and preferred lifetimes for the addresses
* associated with an IA, the client sends a Renew message to the server
* from which the client obtained the addresses in the IA containing an
* IA option for the IA. The client includes IA Address options in the
* IA option for the addresses associated with the IA. The server
* determines new lifetimes for the addresses in the IA according to the
* administrative configuration of the server. The server may also add
* new addresses to the IA. The server may remove addresses from the IA
* by setting the preferred and valid lifetimes of those addresses to
* zero.
*
* The server controls the time at which the client contacts the server
* to extend the lifetimes on assigned addresses through the T1 and T2
* parameters assigned to an IA.
*
* At time T1 for an IA, the client initiates a Renew/Reply message
* exchange to extend the lifetimes on any addresses in the IA. The
* client includes an IA option with all addresses currently assigned to
* the IA in its Renew message.
*
* If T1 or T2 is set to 0 by the server (for an IA_NA) or there are no
* T1 or T2 times (for an IA_TA), the client may send a Renew or Rebind
* message, respectively, at the client's discretion.
*
* The client sets the "msg-type" field to RENEW. The client generates
* a transaction ID and inserts this value in the "transaction-id"
* field.
*
* The client places the identifier of the destination server in a
* Server Identifier option.
*
* The client MUST include a Client Identifier option to identify itself
* to the server. The client adds any appropriate options, including
* one or more IA options. The client MUST include the list of
* addresses the client currently has associated with the IAs in the
* Renew message.
*
* The client MUST include an Option Request option (see section 22.7)
* to indicate the options the client is interested in receiving. The
* client MAY include options with data values as hints to the server
* about parameter values the client would like to have returned.
*/
/* NOINLINE: limit stack usage in caller */
static NOINLINE int send_d6_renew(uint32_t xid, struct in6_addr *server_ipv6, struct in6_addr *our_cur_ipv6)
{
struct d6_packet packet;
uint8_t *opt_ptr;
/* Fill in: msg type, client id */
opt_ptr = init_d6_packet(&packet, DHCPREQUEST, xid);
/* server id */
opt_ptr = mempcpy(opt_ptr, client6_data.server_id, client6_data.server_id->len + 2+2);
/* IA NA (contains requested IP) */
if (client6_data.ia_na)
opt_ptr = mempcpy(opt_ptr, client6_data.ia_na, client6_data.ia_na->len + 2+2);
/* IA PD */
if (client6_data.ia_pd)
opt_ptr = mempcpy(opt_ptr, client6_data.ia_pd, client6_data.ia_pd->len + 2+2);
/* Add options:
* "param req" option according to -O, options specified with -x
*/
opt_ptr = add_d6_client_options(opt_ptr);
bb_error_msg("sending %s", "renew");
if (server_ipv6) {
return d6_send_kernel_packet(
&packet, (opt_ptr - (uint8_t*) &packet),
our_cur_ipv6, CLIENT_PORT6,
server_ipv6, SERVER_PORT6,
client_config.ifindex
/* TODO? send_flags: MSG_DONTROUTE (see IPv4 code for reason why) */
);
}
return d6_mcast_from_client_config_ifindex(&packet, opt_ptr);
}
/* Unicast a DHCP release message */
static int send_d6_release(struct in6_addr *server_ipv6, struct in6_addr *our_cur_ipv6)
{
struct d6_packet packet;
uint8_t *opt_ptr;
/* Fill in: msg type, client id */
opt_ptr = init_d6_packet(&packet, D6_MSG_RELEASE, random_xid());
/* server id */
opt_ptr = mempcpy(opt_ptr, client6_data.server_id, client6_data.server_id->len + 2+2);
/* IA NA (contains our current IP) */
if (client6_data.ia_na)
opt_ptr = mempcpy(opt_ptr, client6_data.ia_na, client6_data.ia_na->len + 2+2);
/* IA PD */
if (client6_data.ia_pd)
opt_ptr = mempcpy(opt_ptr, client6_data.ia_pd, client6_data.ia_pd->len + 2+2);
bb_error_msg("sending %s", "release");
return d6_send_kernel_packet(
&packet, (opt_ptr - (uint8_t*) &packet),
our_cur_ipv6, CLIENT_PORT6,
server_ipv6, SERVER_PORT6,
client_config.ifindex
);
}
/* 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 d6_recv_raw_packet(struct in6_addr *peer_ipv6, struct d6_packet *d6_pkt, int fd)
{
int bytes;
struct ip6_udp_d6_packet packet;
bytes = safe_read(fd, &packet, sizeof(packet));
if (bytes < 0) {
log1("packet read error, ignoring");
/* NB: possible down interface, etc. Caller should pause. */
return bytes; /* returns -1 */
}
if (bytes < (int) (sizeof(packet.ip6) + sizeof(packet.udp))) {
log1("packet is too short, ignoring");
return -2;
}
if (bytes < sizeof(packet.ip6) + ntohs(packet.ip6.ip6_plen)) {
/* packet is bigger than sizeof(packet), we did partial read */
log1("oversized packet, ignoring");
return -2;
}
/* ignore any extra garbage bytes */
bytes = sizeof(packet.ip6) + ntohs(packet.ip6.ip6_plen);
/* make sure its the right packet for us, and that it passes sanity checks */
if (packet.ip6.ip6_nxt != IPPROTO_UDP
|| (packet.ip6.ip6_vfc >> 4) != 6
|| packet.udp.dest != htons(CLIENT_PORT6)
/* || bytes > (int) sizeof(packet) - can't happen */
|| packet.udp.len != packet.ip6.ip6_plen
) {
log1("unrelated/bogus packet, ignoring");
return -2;
}
//How to do this for ipv6?
// /* 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;
// }
if (peer_ipv6)
*peer_ipv6 = packet.ip6.ip6_src; /* struct copy */
log1("received %s", "a packet");
d6_dump_packet(&packet.data);
bytes -= sizeof(packet.ip6) + sizeof(packet.udp);
memcpy(d6_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 d6_raw_socket(int ifindex)
{
int fd;
struct sockaddr_ll sock;
/*
* Comment:
*
* 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.
*
* TODO: make conditional?
*/
#if 0
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_PORT6, else to L4 */
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
/* L3: accept packet */
BPF_STMT(BPF_RET|BPF_K, 0x7fffffff),
/* L4: discard packet */
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,
};
#endif
log2("opening raw socket on ifindex %d", ifindex);
fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IPV6));
log2("got raw socket fd %d", fd);
memset(&sock, 0, sizeof(sock)); /* let's be deterministic */
sock.sll_family = AF_PACKET;
sock.sll_protocol = htons(ETH_P_IPV6);
sock.sll_ifindex = ifindex;
/*sock.sll_hatype = ARPHRD_???;*/
/*sock.sll_pkttype = PACKET_???;*/
/*sock.sll_halen = ???;*/
/*sock.sll_addr[8] = ???;*/
xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
#if 0
if (CLIENT_PORT6 == 546) {
/* Use only if standard port is in use */
/* 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 %d", fd); // log?
}
#endif
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_PORT6, client_config.interface);
else if (new_mode != LISTEN_NONE)
sockfd = d6_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 */
d6_run_script(NULL, "deconfig");
case REQUESTING:
case RELEASED:
change_listen_mode(LISTEN_RAW);
state = INIT_SELECTING;
break;
case INIT_SELECTING:
break;
}
}
static void perform_d6_release(struct in6_addr *server_ipv6, struct in6_addr *our_cur_ipv6)
{
/* send release packet */
if (state == BOUND
|| state == RENEWING
|| state == REBINDING
|| state == RENEW_REQUESTED
) {
bb_error_msg("unicasting a release");
send_d6_release(server_ipv6, our_cur_ipv6); /* 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.
*/
d6_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 udhcpc6_trivial_usage
//usage: "[-fbnq"IF_UDHCP_VERBOSE("v")"odR] [-i IFACE] [-r IPv6] [-s PROG] [-p PIDFILE]\n"
//usage: " [-x OPT:VAL]... [-O OPT]..." IF_FEATURE_UDHCP_PORT(" [-P N]")
//usage:#define udhcpc6_full_usage "\n"
//usage: "\n -i IFACE Interface to use (default eth0)"
//usage: "\n -p FILE Create pidfile"
//usage: "\n -s PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
//usage: "\n -B Request broadcast replies"
//usage: "\n -t N Send up to N discover packets"
//usage: "\n -T N Pause between packets (default 3 seconds)"
//usage: "\n -A N Wait N seconds (default 20) after failure"
//usage: "\n -f Run in foreground"
//usage: USE_FOR_MMU(
//usage: "\n -b Background if lease is not obtained"
//usage: )
//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 -S Log to syslog too"
//usage: IF_FEATURE_UDHCP_PORT(
//usage: "\n -P N Use port N (default 546)"
//usage: )
////usage: IF_FEATURE_UDHCPC_ARPING(
////usage: "\n -a Use arping to validate offered address"
////usage: )
//usage: "\n -O OPT Request option OPT from server (cumulative)"
//usage: "\n -o Don't request any options (unless -O is given)"
//usage: "\n -r IPv6 Request this address ('no' to not request any IP)"
//usage: "\n -d Request prefix"
//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: IF_UDHCP_VERBOSE(
//usage: "\n -v Verbose"
//usage: )
//usage: "\nSignals:"
//usage: "\n USR1 Renew lease"
//usage: "\n USR2 Release lease"
int udhcpc6_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
{
const char *str_r;
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;
struct in6_addr srv6_buf;
struct in6_addr ipv6_buf;
struct in6_addr *requested_ipv6;
uint32_t xid = 0;
int packet_num;
int timeout; /* must be signed */
unsigned already_waited_sec;
unsigned opt;
int retval;
setup_common_bufsiz();
/* We want random_xid to be random */
srand(monotonic_us());
/* Default options */
IF_FEATURE_UDHCP_PORT(SERVER_PORT6 = 547;)
IF_FEATURE_UDHCP_PORT(CLIENT_PORT6 = 546;)
client_config.interface = "eth0";
client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
/* Parse command line */
opt = getopt32long(argv, "^"
/* O,x: list; -T,-t,-A take numeric param */
"i:np:qRr:s:T:+t:+SA:+O:*ox:*fd"
USE_FOR_MMU("b")
///IF_FEATURE_UDHCPC_ARPING("a")
IF_FEATURE_UDHCP_PORT("P:")
"v"
"\0" IF_UDHCP_VERBOSE("vv") /* -v is a counter */
, udhcpc6_longopts
, &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_UDHCP_PORT(, &str_P)
IF_UDHCP_VERBOSE(, &dhcp_verbose)
);
requested_ipv6 = NULL;
option_mask32 |= OPT_r;
if (opt & OPT_r) {
if (strcmp(str_r, "no") == 0) {
option_mask32 -= OPT_r;
} else {
if (inet_pton(AF_INET6, str_r, &ipv6_buf) <= 0)
bb_error_msg_and_die("bad IPv6 address '%s'", str_r);
requested_ipv6 = &ipv6_buf;
}
}
#if ENABLE_FEATURE_UDHCP_PORT
if (opt & OPT_P) {
CLIENT_PORT6 = xatou16(str_P);
SERVER_PORT6 = CLIENT_PORT6 + 1;
}
#endif
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, d6_option_strings);
n = d6_optflags[n].code;
}
client_config.opt_mask[n >> 3] |= 1 << (n & 7);
}
if (!(opt & OPT_o)) {
unsigned i, n;
for (i = 0; (n = d6_optflags[i].code) != 0; i++) {
if (d6_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, d6_optflags, d6_option_strings);
if (colon)
*colon = ':'; /* restore it for NOMMU reexec */
}
if (d6_read_interface(client_config.interface,
&client_config.ifindex,
&client6_data.ll_ip6,
client_config.client_mac)
) {
return 1;
}
/* Create client ID based on mac, set clientid_mac_ptr */
{
struct d6_option *clientid;
clientid = xzalloc(2+2+2+2+6);
clientid->code = D6_OPT_CLIENTID;
clientid->len = 2+2+6;
clientid->data[1] = 3; /* DUID-LL */
clientid->data[3] = 1; /* ethernet */
clientid_mac_ptr = clientid->data + 2+2;
memcpy(clientid_mac_ptr, client_config.client_mac, 6);
client_config.clientid = (void*)clientid;
}
#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();
state = INIT_SELECTING;
d6_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 d6_packet packet;
uint8_t *packet_end;
/* 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 %u seconds", tv);
timestamp_before_wait = (unsigned)monotonic_sec();
retval = poll(pfds, 2, tv < INT_MAX/1000 ? tv * 1000 : INT_MAX);
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("poll");
}
}
/* 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 (d6_read_interface(client_config.interface,
&client_config.ifindex,
&client6_data.ll_ip6,
client_config.client_mac)
) {
goto ret0; /* iface is gone? */
}
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();
/* multicast */
send_d6_discover(xid, requested_ipv6);
timeout = discover_timeout;
packet_num++;
continue;
}
leasefail:
d6_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 (!discover_retries || packet_num < discover_retries) {
/* send multicast select packet */
send_d6_select(xid);
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_d6_renew(xid, &srv6_buf, requested_ipv6);
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_d6_renew(xid, /*server_ipv6:*/ NULL, requested_ipv6);
timeout >>= 1;
continue;
}
/* Timed out, enter init state */
bb_error_msg("lease lost, entering init state");
d6_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_d6_release(&srv6_buf, requested_ipv6);
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 = d6_recv_kernel_packet(&srv6_buf, &packet, sockfd);
else
len = d6_recv_raw_packet(&srv6_buf, &packet, sockfd);
if (len == -1) {
/* Error is severe, reopen socket */
bb_error_msg("read error: "STRERROR_FMT", 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;
packet_end = (uint8_t*)&packet + len;
}
if ((packet.d6_xid32 & htonl(0x00ffffff)) != xid) {
log1("xid %x (our is %x), ignoring packet",
(unsigned)(packet.d6_xid32 & htonl(0x00ffffff)), (unsigned)xid);
continue;
}
switch (state) {
case INIT_SELECTING:
if (packet.d6_msg_type == D6_MSG_ADVERTISE)
goto type_is_ok;
/* DHCPv6 has "Rapid Commit", when instead of Advertise,
* server sends Reply right away.
* Fall through to check for this case.
*/
case REQUESTING:
case RENEWING:
case RENEW_REQUESTED:
case REBINDING:
if (packet.d6_msg_type == D6_MSG_REPLY) {
uint32_t lease_seconds;
struct d6_option *option;
unsigned address_timeout;
unsigned prefix_timeout;
type_is_ok:
address_timeout = 0;
prefix_timeout = 0;
option = d6_find_option(packet.d6_options, packet_end, D6_OPT_STATUS_CODE);
if (option && (option->data[0] | option->data[1]) != 0) {
/* return to init state */
bb_error_msg("received DHCP NAK (%u)", option->data[4]);
d6_run_script(&packet, "nak");
if (state != REQUESTING)
d6_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_ipv6 = NULL;
timeout = 0;
packet_num = 0;
already_waited_sec = 0;
continue;
}
option = d6_copy_option(packet.d6_options, packet_end, D6_OPT_SERVERID);
if (!option) {
bb_error_msg("no server ID, ignoring packet");
continue;
/* still selecting - this server looks bad */
}
//Note: we do not bother comparing server IDs in Advertise and Reply msgs.
//server_id variable is used solely for creation of proper server_id option
//in outgoing packets. (why DHCPv6 even introduced it is a mystery).
free(client6_data.server_id);
client6_data.server_id = option;
if (packet.d6_msg_type == D6_MSG_ADVERTISE) {
/* enter requesting state */
state = REQUESTING;
timeout = 0;
packet_num = 0;
already_waited_sec = 0;
continue;
}
/* It's a D6_MSG_REPLY */
/*
* RFC 3315 18.1.8. Receipt of Reply Messages
*
* Upon the receipt of a valid Reply message in response to a Solicit
* (with a Rapid Commit option), Request, Confirm, Renew, Rebind or
* Information-request message, the client extracts the configuration
* information contained in the Reply. The client MAY choose to report
* any status code or message from the status code option in the Reply
* message.
*
* The client SHOULD perform duplicate address detection [17] on each of
* the addresses in any IAs it receives in the Reply message before
* using that address for traffic. If any of the addresses are found to
* be in use on the link, the client sends a Decline message to the
* server as described in section 18.1.7.
*
* If the Reply was received in response to a Solicit (with a Rapid
* Commit option), Request, Renew or Rebind message, the client updates
* the information it has recorded about IAs from the IA options
* contained in the Reply message:
*
* - Record T1 and T2 times.
*
* - Add any new addresses in the IA option to the IA as recorded by
* the client.
*
* - Update lifetimes for any addresses in the IA option that the
* client already has recorded in the IA.
*
* - Discard any addresses from the IA, as recorded by the client, that
* have a valid lifetime of 0 in the IA Address option.
*
* - Leave unchanged any information about addresses the client has
* recorded in the IA but that were not included in the IA from the
* server.
*
* Management of the specific configuration information is detailed in
* the definition of each option in section 22.
*
* If the client receives a Reply message with a Status Code containing
* UnspecFail, the server is indicating that it was unable to process
* the message due to an unspecified failure condition. If the client
* retransmits the original message to the same server to retry the
* desired operation, the client MUST limit the rate at which it
* retransmits the message and limit the duration of the time during
* which it retransmits the message.
*
* When the client receives a Reply message with a Status Code option
* with the value UseMulticast, the client records the receipt of the
* message and sends subsequent messages to the server through the
* interface on which the message was received using multicast. The
* client resends the original message using multicast.
*
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | OPTION_IA_NA | option-len |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | IAID (4 octets) |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | T1 |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | T2 |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* . IA_NA-options .
* . .
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
*
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | OPTION_IAADDR | option-len |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* | IPv6 address |
* | |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | preferred-lifetime |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | valid-lifetime |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* . .
* . IAaddr-options .
* . .
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
if (option_mask32 & OPT_r) {
struct d6_option *iaaddr;
free(client6_data.ia_na);
client6_data.ia_na = d6_copy_option(packet.d6_options, packet_end, D6_OPT_IA_NA);
if (!client6_data.ia_na) {
bb_error_msg("no %s option, ignoring packet", "IA_NA");
continue;
}
if (client6_data.ia_na->len < (4 + 4 + 4) + (2 + 2 + 16 + 4 + 4)) {
bb_error_msg("%s option is too short:%d bytes",
"IA_NA", client6_data.ia_na->len);
continue;
}
iaaddr = d6_find_option(client6_data.ia_na->data + 4 + 4 + 4,
client6_data.ia_na->data + client6_data.ia_na->len,
D6_OPT_IAADDR
);
if (!iaaddr) {
bb_error_msg("no %s option, ignoring packet", "IAADDR");
continue;
}
if (iaaddr->len < (16 + 4 + 4)) {
bb_error_msg("%s option is too short:%d bytes",
"IAADDR", iaaddr->len);
continue;
}
/* Note: the address is sufficiently aligned for cast:
* we _copied_ IA-NA, and copy is always well-aligned.
*/
requested_ipv6 = (struct in6_addr*) iaaddr->data;
move_from_unaligned32(lease_seconds, iaaddr->data + 16 + 4);
lease_seconds = ntohl(lease_seconds);
/// TODO: check for 0 lease time?
bb_error_msg("%s obtained, lease time %u",
"IPv6", /*inet_ntoa(temp_addr),*/ (unsigned)lease_seconds);
address_timeout = lease_seconds;
}
if (option_mask32 & OPT_d) {
struct d6_option *iaprefix;
free(client6_data.ia_pd);
client6_data.ia_pd = d6_copy_option(packet.d6_options, packet_end, D6_OPT_IA_PD);
if (!client6_data.ia_pd) {
bb_error_msg("no %s option, ignoring packet", "IA_PD");
continue;
}
if (client6_data.ia_pd->len < (4 + 4 + 4) + (2 + 2 + 4 + 4 + 1 + 16)) {
bb_error_msg("%s option is too short:%d bytes",
"IA_PD", client6_data.ia_pd->len);
continue;
}
iaprefix = d6_find_option(client6_data.ia_pd->data + 4 + 4 + 4,
client6_data.ia_pd->data + client6_data.ia_pd->len,
D6_OPT_IAPREFIX
);
if (!iaprefix) {
bb_error_msg("no %s option, ignoring packet", "IAPREFIX");
continue;
}
if (iaprefix->len < (4 + 4 + 1 + 16)) {
bb_error_msg("%s option is too short:%d bytes",
"IAPREFIX", iaprefix->len);
continue;
}
move_from_unaligned32(lease_seconds, iaprefix->data + 4);
lease_seconds = ntohl(lease_seconds);
bb_error_msg("%s obtained, lease time %u",
"prefix", /*inet_ntoa(temp_addr),*/ (unsigned)lease_seconds);
prefix_timeout = lease_seconds;
}
if (!address_timeout)
address_timeout = prefix_timeout;
if (!prefix_timeout)
prefix_timeout = address_timeout;
/* note: "int timeout" will not overflow even with 0xffffffff inputs here: */
timeout = (prefix_timeout < address_timeout ? prefix_timeout : address_timeout) / 2;
/* paranoia: must not be too small */
if (timeout < 0x10)
timeout = 0x10;
/* enter bound state */
d6_run_script(&packet, state == REQUESTING ? "bound" : "renew");
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
already_waited_sec = 0;
continue; /* back to main loop */
}
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_d6_release(&srv6_buf, requested_ipv6);
retval = 0;
ret:
/*if (client_config.pidfile) - remove_pidfile has its own check */
remove_pidfile(client_config.pidfile);
return retval;
}