1485 lines
50 KiB
C
1485 lines
50 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* DHCPv6 client.
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*
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* 2011-11.
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* WARNING: THIS CODE IS INCOMPLETE. IT IS NOWHERE NEAR
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* TO BE READY FOR PRODUCTION USE.
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*
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* Copyright (C) 2011 Denys Vlasenko.
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*
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* Licensed under GPLv2, see file LICENSE in this source tree.
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*/
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//config:config UDHCPC6
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//config: bool "udhcp client for DHCPv6 (udhcpc6)"
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//config: default n # not yet ready
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//config: depends on FEATURE_IPV6
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//config: help
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//config: udhcpc6 is a DHCPv6 client
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//applet:IF_UDHCPC6(APPLET(udhcpc6, BB_DIR_USR_BIN, BB_SUID_DROP))
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//kbuild:lib-$(CONFIG_UDHCPC6) += d6_dhcpc.o d6_packet.o d6_socket.o common.o socket.o signalpipe.o
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#include <syslog.h>
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/* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
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#define WANT_PIDFILE 1
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#include "common.h"
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#include "dhcpd.h"
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#include "dhcpc.h"
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#include "d6_common.h"
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#include <netinet/if_ether.h>
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#include <netpacket/packet.h>
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#include <linux/filter.h>
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/* "struct client_config_t client_config" is in bb_common_bufsiz1 */
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#if ENABLE_LONG_OPTS
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static const char udhcpc6_longopts[] ALIGN1 =
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"interface\0" Required_argument "i"
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"now\0" No_argument "n"
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"pidfile\0" Required_argument "p"
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"quit\0" No_argument "q"
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"release\0" No_argument "R"
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"request\0" Required_argument "r"
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"script\0" Required_argument "s"
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"timeout\0" Required_argument "T"
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"retries\0" Required_argument "t"
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"tryagain\0" Required_argument "A"
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"syslog\0" No_argument "S"
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"request-option\0" Required_argument "O"
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"no-default-options\0" No_argument "o"
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"foreground\0" No_argument "f"
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"background\0" No_argument "b"
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/// IF_FEATURE_UDHCPC_ARPING("arping\0" No_argument "a")
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IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
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;
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#endif
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/* Must match getopt32 option string order */
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enum {
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OPT_i = 1 << 0,
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OPT_n = 1 << 1,
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OPT_p = 1 << 2,
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OPT_q = 1 << 3,
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OPT_R = 1 << 4,
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OPT_r = 1 << 5,
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OPT_s = 1 << 6,
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OPT_T = 1 << 7,
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OPT_t = 1 << 8,
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OPT_S = 1 << 9,
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OPT_A = 1 << 10,
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OPT_O = 1 << 11,
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OPT_o = 1 << 12,
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OPT_x = 1 << 13,
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OPT_f = 1 << 14,
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/* The rest has variable bit positions, need to be clever */
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OPTBIT_f = 14,
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USE_FOR_MMU( OPTBIT_b,)
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///IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
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IF_FEATURE_UDHCP_PORT( OPTBIT_P,)
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USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
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///IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
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IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
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};
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/*** Utility functions ***/
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static void *d6_find_option(uint8_t *option, uint8_t *option_end, unsigned code)
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{
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/* "length minus 4" */
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int len_m4 = option_end - option - 4;
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while (len_m4 >= 0) {
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/* Next option's len is too big? */
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if (option[3] > len_m4)
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return NULL; /* yes. bogus packet! */
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/* So far we treat any opts with code >255
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* or len >255 as bogus, and stop at once.
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* This simplifies big-endian handling.
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*/
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if (option[0] != 0 || option[2] != 0)
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return NULL;
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/* Option seems to be valid */
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/* Does its code match? */
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if (option[1] == code)
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return option; /* yes! */
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option += option[3] + 4;
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len_m4 -= option[3] + 4;
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}
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return NULL;
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}
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static void *d6_copy_option(uint8_t *option, uint8_t *option_end, unsigned code)
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{
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uint8_t *opt = d6_find_option(option, option_end, code);
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if (!opt)
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return opt;
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return memcpy(xmalloc(opt[3] + 4), opt, opt[3] + 4);
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}
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static void *d6_store_blob(void *dst, const void *src, unsigned len)
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{
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memcpy(dst, src, len);
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return dst + len;
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}
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/*** Script execution code ***/
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static char** new_env(void)
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{
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client6_data.env_ptr = xrealloc_vector(client6_data.env_ptr, 3, client6_data.env_idx);
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return &client6_data.env_ptr[client6_data.env_idx++];
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}
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/* put all the parameters into the environment */
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static void option_to_env(uint8_t *option, uint8_t *option_end)
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{
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/* "length minus 4" */
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int len_m4 = option_end - option - 4;
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while (len_m4 >= 0) {
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uint32_t v32;
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char ipv6str[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff")];
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if (option[0] != 0 || option[2] != 0)
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break;
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switch (option[1]) {
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//case D6_OPT_CLIENTID:
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//case D6_OPT_SERVERID:
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case D6_OPT_IA_NA:
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case D6_OPT_IA_PD:
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option_to_env(option + 16, option + 4 + option[3]);
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break;
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//case D6_OPT_IA_TA:
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case D6_OPT_IAADDR:
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/* 0 1 2 3
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* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | OPTION_IAADDR | option-len |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | |
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* | IPv6 address |
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* | |
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* | |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | preferred-lifetime |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | valid-lifetime |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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*/
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sprint_nip6(ipv6str, option + 4);
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*new_env() = xasprintf("ipv6=%s", ipv6str);
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move_from_unaligned32(v32, option + 4 + 16 + 4);
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*new_env() = xasprintf("lease=%u", (unsigned)v32);
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break;
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//case D6_OPT_ORO:
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//case D6_OPT_PREFERENCE:
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//case D6_OPT_ELAPSED_TIME:
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//case D6_OPT_RELAY_MSG:
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//case D6_OPT_AUTH:
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//case D6_OPT_UNICAST:
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//case D6_OPT_STATUS_CODE:
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//case D6_OPT_RAPID_COMMIT:
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//case D6_OPT_USER_CLASS:
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//case D6_OPT_VENDOR_CLASS:
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//case D6_OPT_VENDOR_OPTS:
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//case D6_OPT_INTERFACE_ID:
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//case D6_OPT_RECONF_MSG:
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//case D6_OPT_RECONF_ACCEPT:
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case D6_OPT_IAPREFIX:
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/* 0 1 2 3
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* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | OPTION_IAPREFIX | option-length |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | preferred-lifetime |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | valid-lifetime |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | prefix-length | |
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* +-+-+-+-+-+-+-+-+ IPv6 prefix |
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* | (16 octets) |
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* | |
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* | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | |
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* +-+-+-+-+-+-+-+-+
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*/
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//move_from_unaligned32(v32, option + 4 + 4);
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//*new_env() = xasprintf("lease=%u", (unsigned)v32);
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sprint_nip6(ipv6str, option + 4 + 4 + 1);
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*new_env() = xasprintf("ipv6prefix=%s/%u", ipv6str, (unsigned)(option[4 + 4]));
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}
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option += 4 + option[3];
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len_m4 -= 4 + option[3];
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}
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}
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static char **fill_envp(struct d6_packet *packet)
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{
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char **envp, **curr;
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client6_data.env_ptr = NULL;
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client6_data.env_idx = 0;
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*new_env() = xasprintf("interface=%s", client_config.interface);
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if (packet)
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option_to_env(packet->d6_options, packet->d6_options + sizeof(packet->d6_options));
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envp = curr = client6_data.env_ptr;
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while (*curr)
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putenv(*curr++);
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return envp;
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}
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/* Call a script with a par file and env vars */
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static void d6_run_script(struct d6_packet *packet, const char *name)
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{
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char **envp, **curr;
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char *argv[3];
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envp = fill_envp(packet);
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/* call script */
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log1("Executing %s %s", client_config.script, name);
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argv[0] = (char*) client_config.script;
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argv[1] = (char*) name;
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argv[2] = NULL;
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spawn_and_wait(argv);
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for (curr = envp; *curr; curr++) {
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log2(" %s", *curr);
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bb_unsetenv_and_free(*curr);
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}
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free(envp);
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}
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/*** Sending/receiving packets ***/
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static ALWAYS_INLINE uint32_t random_xid(void)
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{
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uint32_t t = rand() & htonl(0x00ffffff);
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return t;
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}
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/* Initialize the packet with the proper defaults */
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static uint8_t *init_d6_packet(struct d6_packet *packet, char type, uint32_t xid)
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{
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struct d6_option *clientid;
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memset(packet, 0, sizeof(*packet));
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packet->d6_xid32 = xid;
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packet->d6_msg_type = type;
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clientid = (void*)client_config.clientid;
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return d6_store_blob(packet->d6_options, clientid, clientid->len + 2+2);
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}
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static uint8_t *add_d6_client_options(uint8_t *ptr)
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{
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return ptr;
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//uint8_t c;
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//int i, end, len;
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/* Add a "param req" option with the list of options we'd like to have
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* from stubborn DHCP servers. Pull the data from the struct in common.c.
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* No bounds checking because it goes towards the head of the packet. */
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//...
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/* Add -x options if any */
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//...
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}
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static int d6_mcast_from_client_config_ifindex(struct d6_packet *packet, uint8_t *end)
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{
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static const uint8_t FF02__1_2[16] = {
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0xFF, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x02,
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};
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return d6_send_raw_packet(
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packet, (end - (uint8_t*) packet),
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/*src*/ NULL, CLIENT_PORT,
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/*dst*/ (struct in6_addr*)FF02__1_2, SERVER_PORT, MAC_BCAST_ADDR,
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client_config.ifindex
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);
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}
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/* Milticast a DHCPv6 Solicit packet to the network, with an optionally requested IP.
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*
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* RFC 3315 17.1.1. Creation of Solicit Messages
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*
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* The client MUST include a Client Identifier option to identify itself
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* to the server. The client includes IA options for any IAs to which
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* it wants the server to assign addresses. The client MAY include
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* addresses in the IAs as a hint to the server about addresses for
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* which the client has a preference. ...
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*
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* The client uses IA_NA options to request the assignment of non-
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* temporary addresses and uses IA_TA options to request the assignment
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* of temporary addresses. Either IA_NA or IA_TA options, or a
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* combination of both, can be included in DHCP messages.
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*
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* The client SHOULD include an Option Request option (see section 22.7)
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* to indicate the options the client is interested in receiving. The
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* client MAY additionally include instances of those options that are
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* identified in the Option Request option, with data values as hints to
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* the server about parameter values the client would like to have
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* returned.
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*
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* The client includes a Reconfigure Accept option (see section 22.20)
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* if the client is willing to accept Reconfigure messages from the
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* server.
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| OPTION_CLIENTID | option-len |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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. .
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. DUID .
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. (variable length) .
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. .
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| OPTION_IA_NA | option-len |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| IAID (4 octets) |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| T1 |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| T2 |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| |
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. IA_NA-options .
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. .
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| OPTION_IAADDR | option-len |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| |
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| IPv6 address |
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| |
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| |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| preferred-lifetime |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| valid-lifetime |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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. .
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. IAaddr-options .
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. .
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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|
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| OPTION_ORO | option-len |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| requested-option-code-1 | requested-option-code-2 |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| ... |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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|
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| OPTION_RECONF_ACCEPT | 0 |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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*/
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/* NOINLINE: limit stack usage in caller */
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static NOINLINE int send_d6_discover(uint32_t xid, struct in6_addr *requested_ipv6)
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{
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struct d6_packet packet;
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uint8_t *opt_ptr;
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unsigned len;
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/* Fill in: msg type, client id */
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opt_ptr = init_d6_packet(&packet, D6_MSG_SOLICIT, xid);
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/* Create new IA_NA, optionally with included IAADDR with requested IP */
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free(client6_data.ia_na);
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len = requested_ipv6 ? 2+2+4+4+4 + 2+2+16+4+4 : 2+2+4+4+4;
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client6_data.ia_na = xzalloc(len);
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client6_data.ia_na->code = D6_OPT_IA_NA;
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client6_data.ia_na->len = len - 4;
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*(uint32_t*)client6_data.ia_na->data = rand(); /* IAID */
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if (requested_ipv6) {
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struct d6_option *iaaddr = (void*)(client6_data.ia_na->data + 4+4+4);
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iaaddr->code = D6_OPT_IAADDR;
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iaaddr->len = 16+4+4;
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memcpy(iaaddr->data, requested_ipv6, 16);
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}
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opt_ptr = d6_store_blob(opt_ptr, client6_data.ia_na, len);
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/* Add options:
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* "param req" option according to -O, options specified with -x
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*/
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opt_ptr = add_d6_client_options(opt_ptr);
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bb_info_msg("Sending discover...");
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return d6_mcast_from_client_config_ifindex(&packet, opt_ptr);
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}
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/* Multicast a DHCPv6 request message
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*
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* RFC 3315 18.1.1. Creation and Transmission of Request Messages
|
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*
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* The client uses a Request message to populate IAs with addresses and
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* obtain other configuration information. The client includes one or
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* more IA options in the Request message. The server then returns
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* addresses and other information about the IAs to the client in IA
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* options in a Reply message.
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*
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* The client generates a transaction ID and inserts this value in the
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* "transaction-id" field.
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*
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* The client places the identifier of the destination server in a
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* Server Identifier option.
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*
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* The client MUST include a Client Identifier option to identify itself
|
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* to the server. The client adds any other appropriate options,
|
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* including one or more IA options (if the client is requesting that
|
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* the server assign it some network addresses).
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*
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* The client MUST include an Option Request option (see section 22.7)
|
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* to indicate the options the client is interested in receiving. The
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* client MAY include options with data values as hints to the server
|
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* about parameter values the client would like to have returned.
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*
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* The client includes a Reconfigure Accept option (see section 22.20)
|
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* indicating whether or not the client is willing to accept Reconfigure
|
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* messages from the server.
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*/
|
|
/* NOINLINE: limit stack usage in caller */
|
|
static NOINLINE int send_d6_select(uint32_t xid)
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{
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struct d6_packet packet;
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uint8_t *opt_ptr;
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|
|
/* Fill in: msg type, client id */
|
|
opt_ptr = init_d6_packet(&packet, D6_MSG_REQUEST, xid);
|
|
|
|
/* server id */
|
|
opt_ptr = d6_store_blob(opt_ptr, client6_data.server_id, client6_data.server_id->len + 2+2);
|
|
/* IA NA (contains requested IP) */
|
|
opt_ptr = d6_store_blob(opt_ptr, client6_data.ia_na, client6_data.ia_na->len + 2+2);
|
|
|
|
/* Add options:
|
|
* "param req" option according to -O, options specified with -x
|
|
*/
|
|
opt_ptr = add_d6_client_options(opt_ptr);
|
|
|
|
bb_info_msg("Sending 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 = d6_store_blob(opt_ptr, client6_data.server_id, client6_data.server_id->len + 2+2);
|
|
/* IA NA (contains requested IP) */
|
|
opt_ptr = d6_store_blob(opt_ptr, client6_data.ia_na, client6_data.ia_na->len + 2+2);
|
|
|
|
/* Add options:
|
|
* "param req" option according to -O, options specified with -x
|
|
*/
|
|
opt_ptr = add_d6_client_options(opt_ptr);
|
|
|
|
bb_info_msg("Sending renew...");
|
|
if (server_ipv6)
|
|
return d6_send_kernel_packet(
|
|
&packet, (opt_ptr - (uint8_t*) &packet),
|
|
our_cur_ipv6, CLIENT_PORT,
|
|
server_ipv6, SERVER_PORT
|
|
);
|
|
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 = d6_store_blob(opt_ptr, client6_data.server_id, client6_data.server_id->len + 2+2);
|
|
/* IA NA (contains our current IP) */
|
|
opt_ptr = d6_store_blob(opt_ptr, client6_data.ia_na, client6_data.ia_na->len + 2+2);
|
|
|
|
bb_info_msg("Sending release...");
|
|
return d6_send_kernel_packet(
|
|
&packet, (opt_ptr - (uint8_t*) &packet),
|
|
our_cur_ipv6, CLIENT_PORT,
|
|
server_ipv6, SERVER_PORT
|
|
);
|
|
}
|
|
|
|
/* 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
|
|
UNUSED_PARAM
|
|
, 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_PORT)
|
|
/* || 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;
|
|
// }
|
|
|
|
log1("Received 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_PORT, else to L4 */
|
|
BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 68, 0, 1),
|
|
/* L3: accept packet */
|
|
BPF_STMT(BPF_RET|BPF_K, 0xffffffff),
|
|
/* 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
|
|
|
|
log1("Opening raw socket on ifindex %d", ifindex); //log2?
|
|
|
|
fd = xsocket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IPV6));
|
|
log1("Got raw socket fd %d", fd); //log2?
|
|
|
|
sock.sll_family = AF_PACKET;
|
|
sock.sll_protocol = htons(ETH_P_IPV6);
|
|
sock.sll_ifindex = ifindex;
|
|
xbind(fd, (struct sockaddr *) &sock, sizeof(sock));
|
|
|
|
#if 0
|
|
if (CLIENT_PORT == 68) {
|
|
/* 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_PORT, 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_info_msg("Performing a 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) {
|
|
bb_info_msg("Unicasting a release");
|
|
send_d6_release(server_ipv6, our_cur_ipv6); /* unicast */
|
|
d6_run_script(NULL, "deconfig");
|
|
}
|
|
bb_info_msg("Entering released state");
|
|
|
|
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")"oR] [-i IFACE] [-r IP] [-s PROG] [-p PIDFILE]\n"
|
|
//usage: " [-x OPT:VAL]... [-O OPT]..." IF_FEATURE_UDHCP_PORT(" [-P N]")
|
|
//usage:#define udhcpc6_full_usage "\n"
|
|
//usage: IF_LONG_OPTS(
|
|
//usage: "\n -i,--interface IFACE Interface to use (default eth0)"
|
|
//usage: "\n -p,--pidfile FILE Create pidfile"
|
|
//usage: "\n -s,--script PROG Run PROG at DHCP events (default "CONFIG_UDHCPC_DEFAULT_SCRIPT")"
|
|
//usage: "\n -B,--broadcast Request broadcast replies"
|
|
//usage: "\n -t,--retries N Send up to N discover packets"
|
|
//usage: "\n -T,--timeout N Pause between packets (default 3 seconds)"
|
|
//usage: "\n -A,--tryagain N Wait N seconds after failure (default 20)"
|
|
//usage: "\n -f,--foreground Run in foreground"
|
|
//usage: USE_FOR_MMU(
|
|
//usage: "\n -b,--background Background if lease is not obtained"
|
|
//usage: )
|
|
//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 -S,--syslog Log to syslog too"
|
|
//usage: IF_FEATURE_UDHCP_PORT(
|
|
//usage: "\n -P,--client-port N Use port N (default 546)"
|
|
//usage: )
|
|
////usage: IF_FEATURE_UDHCPC_ARPING(
|
|
////usage: "\n -a,--arping Use arping to validate offered address"
|
|
////usage: )
|
|
//usage: "\n -O,--request-option OPT Request option OPT from server (cumulative)"
|
|
//usage: "\n -o,--no-default-options Don't request any options (unless -O is given)"
|
|
//usage: "\n -r,--request IP Request this IP address"
|
|
//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: )
|
|
//usage: IF_NOT_LONG_OPTS(
|
|
//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 IP Request this IP address"
|
|
//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: )
|
|
//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 max_fd;
|
|
int retval;
|
|
fd_set rfds;
|
|
|
|
/* Default options */
|
|
IF_FEATURE_UDHCP_PORT(SERVER_PORT = 547;)
|
|
IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 546;)
|
|
client_config.interface = "eth0";
|
|
client_config.script = CONFIG_UDHCPC_DEFAULT_SCRIPT;
|
|
|
|
/* Parse command line */
|
|
/* O,x: list; -T,-t,-A take numeric param */
|
|
opt_complementary = "O::x::T+:t+:A+" IF_UDHCP_VERBOSE(":vv") ;
|
|
IF_LONG_OPTS(applet_long_options = udhcpc6_longopts;)
|
|
opt = getopt32(argv, "i:np:qRr:s:T:t:SA:O:ox:f"
|
|
USE_FOR_MMU("b")
|
|
///IF_FEATURE_UDHCPC_ARPING("a")
|
|
IF_FEATURE_UDHCP_PORT("P:")
|
|
"v"
|
|
, &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;
|
|
if (opt & OPT_r) {
|
|
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_PORT = xatou16(str_P);
|
|
SERVER_PORT = CLIENT_PORT - 1;
|
|
}
|
|
#endif
|
|
if (opt & OPT_o)
|
|
client_config.no_default_options = 1;
|
|
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);
|
|
}
|
|
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;
|
|
}
|
|
|
|
/* 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_info_msg("%s (v"BB_VER") started", applet_name);
|
|
/* Set up the signal pipe */
|
|
udhcp_sp_setup();
|
|
/* We want random_xid to be random... */
|
|
srand(monotonic_us());
|
|
|
|
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 (;;) {
|
|
struct timeval tv;
|
|
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:"). */
|
|
|
|
max_fd = udhcp_sp_fd_set(&rfds, sockfd);
|
|
|
|
tv.tv_sec = timeout - already_waited_sec;
|
|
tv.tv_usec = 0;
|
|
retval = 0;
|
|
/* If we already timed out, fall through with retval = 0, else... */
|
|
if ((int)tv.tv_sec > 0) {
|
|
log1("Waiting on select %u seconds", (int)tv.tv_sec);
|
|
timestamp_before_wait = (unsigned)monotonic_sec();
|
|
retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
|
|
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? */
|
|
}
|
|
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 (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_info_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_info_msg("No lease, failing");
|
|
retval = 1;
|
|
goto ret;
|
|
}
|
|
/* wait before trying again */
|
|
timeout = tryagain_timeout;
|
|
packet_num = 0;
|
|
continue;
|
|
case REQUESTING:
|
|
if (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_info_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 FD_ISSET before reading */
|
|
switch (udhcp_sp_read(&rfds)) {
|
|
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_info_msg("Received SIGTERM");
|
|
goto ret0;
|
|
}
|
|
|
|
/* Is it a packet? */
|
|
if (listen_mode == LISTEN_NONE || !FD_ISSET(sockfd, &rfds))
|
|
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_info_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;
|
|
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, *iaaddr;
|
|
type_is_ok:
|
|
option = d6_find_option(packet.d6_options, packet_end, D6_OPT_STATUS_CODE);
|
|
if (option && option->data[4] != 0) {
|
|
/* return to init state */
|
|
bb_info_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 .
|
|
* . .
|
|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
*/
|
|
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("IA_NA option is too short:%d bytes", 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("IAADDR option is too short:%d bytes", 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);
|
|
/* paranoia: must not be too small and not prone to overflows */
|
|
if (lease_seconds < 0x10)
|
|
lease_seconds = 0x10;
|
|
/// TODO: check for 0 lease time?
|
|
if (lease_seconds >= 0x10000000)
|
|
lease_seconds = 0x0fffffff;
|
|
/* enter bound state */
|
|
timeout = lease_seconds / 2;
|
|
bb_info_msg("Lease obtained, lease time %u",
|
|
/*inet_ntoa(temp_addr),*/ (unsigned)lease_seconds);
|
|
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;
|
|
}
|