There are cases where binding to source IP and
destination IP is insufficient to guarantee sane
xmit netdev.
One case where this can fail is when
route-matching netdev carrier is down (cable
unplugged, wifi disconnected), or the netdev is
admin down. Then all the IP based bindings (bind()
+ connect()) will seemingly succeed but the actual
packet can go out through a default gw path.
Depending on the network this happens on
it can create issues or false alarms. It can
also leak some subnet info across networks that
shouldn't be routed.
As such better be safe than sorry and bind to a
netdev to be sure it's used for xmit.
function old new delta
udhcp_send_kernel_packet 293 336 +43
send_packet 182 188 +6
bcast_or_ucast 37 43 +6
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/0 up/down: 55/0) Total: 55 bytes
Signed-off-by: Michal Kazior <michal@plume.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Duplicate options are currently overridden (only the last option is kept).
This leads to unexpected behavior when using long options.
The patch adds support for long options in compliance with RFC 3396.
Fixes#13136.
function old new delta
udhcp_run_script 601 725 +124
optitem_unset_env_and_free - 38 +38
putenvp 46 59 +13
static.xmalloc_optname_optval 718 717 -1
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 2/1 up/down: 175/-1) Total: 174 bytes
Signed-off-by: Martin Lewis <martin.lewis.x84@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
fill_envp now iterates over the packet only once instead of a few hundred times
using the new option scanner.
function old new delta
udhcp_scan_options - 189 +189
putenvp - 46 +46
init_scan_state - 22 +22
udhcp_get_option 227 104 -123
udhcp_run_script 835 601 -234
------------------------------------------------------------------------------
(add/remove: 3/0 grow/shrink: 0/2 up/down: 257/-357) Total: -100 bytes
Signed-off-by: Martin Lewis <martin.lewis.x84@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Incorporated valid_domain_label into good_hostname to simplify the implementation.
function old new delta
static.xmalloc_optname_optval 973 958 -15
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-15) Total: -15 bytes
text data bss dec hex filename
993144 16915 1872 1011931 f70db busybox_old
993129 16915 1872 1011916 f70cc busybox_unstripped
Signed-off-by: Martin Lewis <martin.lewis.x84@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Back in 2007, commit 0c97c9d437 ("'simple' error message functions by
Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower
overhead call to bb_perror_msg() when only a string was being printed
with no parameters. This saves space for some CPU architectures because
it avoids the overhead of a call to a variadic function. However there
has never been a simple version of bb_error_msg(), and since 2007 many
new calls to bb_perror_msg() have been added that only take a single
parameter and so could have been using bb_simple_perror_message().
This changeset introduces 'simple' versions of bb_info_msg(),
bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and
bb_herror_msg_and_die(), and replaces all calls that only take a
single parameter, or use something like ("%s", arg), with calls to the
corresponding 'simple' version.
Since it is likely that single parameter calls to the variadic functions
may be accidentally reintroduced in the future a new debugging config
option WARN_SIMPLE_MSG has been introduced. This uses some macro magic
which will cause any such calls to generate a warning, but this is
turned off by default to avoid use of the unpleasant macros in normal
circumstances.
This is a large changeset due to the number of calls that have been
replaced. The only files that contain changes other than simple
substitution of function calls are libbb.h, libbb/herror_msg.c,
libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c,
networking/udhcp/common.h and util-linux/mdev.c additonal macros have
been added for logging so that single parameter and multiple parameter
logging variants exist.
The amount of space saved varies considerably by architecture, and was
found to be as follows (for 'defconfig' using GCC 7.4):
Arm: -92 bytes
MIPS: -52 bytes
PPC: -1836 bytes
x86_64: -938 bytes
Note that for the MIPS architecture only an exception had to be made
disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h)
because it made these files larger on MIPS.
Signed-off-by: James Byrne <james.byrne@origamienergy.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Resolved a TODO by adding support for gateway_nip parameter.
function old new delta
udhcp_run_script 792 835 +43
Signed-off-by: Martin Lewis <martin.lewis.x84@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Between Busybox 1.24.2 and 1.25.0 the bb_info_msg() function was
eliminated and calls to it changed to be bb_error_msg(). The downside of
this is that daemons now log all messages to syslog at the LOG_ERR level
which makes it hard to filter errors from informational messages.
This change optionally re-introduces bb_info_msg(), controlled by a new
option FEATURE_SYSLOG_INFO, restores all the calls to bb_info_msg() that
were removed (only in applets that set logmode to LOGMODE_SYSLOG or
LOGMODE_BOTH), and also changes informational messages in ifplugd and
ntpd.
The code size change of this is as follows (using 'defconfig' on x86_64
with gcc 7.3.0-27ubuntu1~18.04)
function old new delta
bb_info_msg - 182 +182
bb_vinfo_msg - 27 +27
static.log7 194 198 +4
log8 190 191 +1
log5 190 191 +1
crondlog 45 - -45
------------------------------------------------------------------------------
(add/remove: 2/1 grow/shrink: 3/0 up/down: 215/-45) Total: 170 bytes
If you don't care about everything being logged at LOG_ERR level
then when FEATURE_SYSLOG_INFO is disabled Busybox actually gets smaller:
function old new delta
static.log7 194 200 +6
log8 190 193 +3
log5 190 193 +3
syslog_level 1 - -1
bb_verror_msg 583 581 -2
crondlog 45 - -45
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 3/1 up/down: 12/-48) Total: -36 bytes
Signed-off-by: James Byrne <james.byrne@origamienergy.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Currently, running "udhcpc -n -b" causes udhcpc to go to background and
then exit after some time unless a lease is obtained.
It's not very useful to do so
as the calling process doesn't know
if the lease was obtained or not anyway.
The code actually tries to favor "-b" over "-n",
but doesn't clear "-n" flag while clearing "-b" after backgrounding.
So, clear "-n" flag after going into background.
This effectively makes "-b" override "-n" completely
and "-n -b" behave the same as "-b".
This allows to override default "-n" option, passed to udhcpc by ifupdown,
without recompiling busybox.
URL: https://bugs.busybox.net/11691
Signed-off-by: Andrey Mazo <ahippo@yandex.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
The caps were inconsistent: timeout to renew was capped at 20 seconds,
and any renews with timeout <= 60 seconds were forced to broadcast.
function old new delta
udhcpc_main 2683 2680 -3
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This reverts "udhcpc: paranoia when using kernel UDP mode
for sending renew: server ID may be bogus".
Users complain that they do have servers behind routers
(with DHCP relays).
function old new delta
send_packet 168 166 -2
bcast_or_ucast 25 23 -2
udhcp_send_kernel_packet 301 295 -6
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-10) Total: -10 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Fixes:
commit 52a515d187
"udhcp: use poll() instead of select()"
Feb 16 2017
udhcp_sp_read() is meant to check whether signal pipe indeed has some data to read.
In the above commit, it was changed as follows:
- if (!FD_ISSET(signal_pipe.rd, rfds))
+ if (!pfds[0].revents)
return 0;
The problem is, the check was working for select() purely by accident.
Caught signal interrupts select()/poll() syscalls, they return with EINTR
(regardless of SA_RESTART flag in sigaction). _Then_ signal handler is invoked.
IOW: they can't see any changes to fd state caused by signal haldler
(in our case, signal handler makes signal pipe ready to be read).
For select(), it means that rfds[] bit array is unmodified, bit of signal
pipe's read fd is still set, and the above check "works": it thinks select()
says there is data to read.
This accident does not work for poll(): .revents stays clear, and we do not
try reading signal pipe as we should. In udhcpd, we fall through and block
in socket read. Further SIGTERM signals simply cause socket read to be
interrupted and then restarted (since SIGTERM handler has SA_RESTART=1).
Fixing this as follows: remove the check altogether. Set signal pipe read fd
to nonblocking mode. Always read it in udhcp_sp_read().
If read fails, assume it's EAGAIN and return 0 ("no signal seen").
udhcpd avoids reading signal pipe on every recvd packet by looping if EINTR
(using safe_poll()) - thus ensuring we have correct .revents for all fds -
and calling udhcp_sp_read() only if pfds[0].revents!=0.
udhcpc performs much fewer reads (typically it sleeps >99.999% of the time),
there is no need to optimize it: can call udhcp_sp_read() after each poll
unconditionally.
To robustify socket reads, unconditionally set pfds[1].revents=0
in udhcp_sp_fd_set() (which is before poll), and check it before reading
network socket in udhcpd.
TODO:
This might still fail: if pfds[1].revents=POLLIN, socket read may still block.
There are rare cases when select/poll indicates that data can be read,
but then actual read still blocks (one such case is UDP packets with
wrong checksum). General advise is, if you use a poll/select loop,
keep all your fds nonblocking.
Maybe we should also do that to our network sockets?
function old new delta
udhcp_sp_setup 55 65 +10
udhcp_sp_fd_set 54 60 +6
udhcp_sp_read 46 36 -10
udhcpd_main 1451 1437 -14
udhcpc_main 2723 2708 -15
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/3 up/down: 16/-39) Total: -23 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Since bb_info_msg() was eliminated type of buffering on stdout is not important
function old new delta
udhcpd_main 1463 1451 -12
udhcpc_main 2735 2723 -12
setlinebuf 19 - -19
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 0/2 up/down: 0/-43) Total: -43 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
With new code, we request that target IP (server ID) must be directly reachable.
If it's not, this happens:
udhcpc: waiting 2000 seconds
udhcpc: entering listen mode: kernel
udhcpc: opening listen socket on *:68 wlan0
udhcpc: entering renew state
udhcpc: sending renew to 1.1.1.1
udhcpc: send: Network is unreachable
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 1.1.1.1 needs routing, this is fishy!
udhcpc: entering rebinding state
udhcpc: entering listen mode: raw
udhcpc: created raw socket
udhcpc: sending renew to 0.0.0.0
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ going to use broadcast
which is the desired behavior. Before the patch, packet to 1.1.1.1 was routed
over eth0 (!) and maybe even into Internet (!!!).
function old new delta
udhcpc_main 2752 2763 +11
udhcp_send_kernel_packet 295 301 +6
send_renew 82 84 +2
send_packet 166 168 +2
bcast_or_ucast 23 25 +2
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 5/0 up/down: 23/0) Total: 23 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
I see random field values like sll_hatype=0x267 when I strace.
They seem to not matter, but just in case they sometimes do,
let's at least have deterministic values (via memset(0)).
function old new delta
change_listen_mode 308 322 +14
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
FEATURE_GETOPT_LONG made dependent on LONG_OPTS.
The folloving options are removed, now LONG_OPTS enables long options
for affected applets:
FEATURE_ENV_LONG_OPTIONS FEATURE_EXPAND_LONG_OPTIONS
FEATURE_UNEXPAND_LONG_OPTIONS FEATURE_MKDIR_LONG_OPTIONS
FEATURE_MV_LONG_OPTIONS FEATURE_RMDIR_LONG_OPTIONS
FEATURE_ADDGROUP_LONG_OPTIONS FEATURE_ADDUSER_LONG_OPTIONS
FEATURE_HWCLOCK_LONG_OPTIONS FEATURE_NSENTER_LONG_OPTS
FEATURE_CHCON_LONG_OPTIONS FEATURE_RUNCON_LONG_OPTIONS
They either had a small number of long options, or their long options are
essential.
Example: upstream addgroup and adduser have ONLY longopts,
we should probably go further and get rid
of non-standard short options.
To this end, make addgroup and adduser "select LONG_OPTS".
We had this breakage caused by us even in our own package!
#if ENABLE_LONG_OPTS || !ENABLE_ADDGROUP
/* We try to use --gid, not -g, because "standard" addgroup
* has no short option -g, it has only long --gid.
*/
argv[1] = (char*)"--gid";
#else
/* Breaks if system in fact does NOT use busybox addgroup */
argv[1] = (char*)"-g";
#endif
xargs: its lone longopt no longer depends on DESKTOP, only on LONG_OPTS.
hwclock TODO: get rid of incompatible -t, -l aliases to --systz, --localtime
Shorten help texts by omitting long option when short opt alternative exists.
Reduction of size comes from the fact that store of an immediate
(an address of longopts) to a fixed address (global variable)
is a longer insn than pushing that immediate or passing it in a register.
This effect is CPU-agnostic.
function old new delta
getopt32 1350 22 -1328
vgetopt32 - 1318 +1318
getopt32long - 24 +24
tftpd_main 562 567 +5
scan_recursive 376 380 +4
collect_cpu 545 546 +1
date_main 1096 1095 -1
hostname_main 262 259 -3
uname_main 259 255 -4
setpriv_main 362 358 -4
rmdir_main 191 187 -4
mv_main 562 558 -4
ipcalc_main 548 544 -4
ifenslave_main 641 637 -4
gzip_main 192 188 -4
gunzip_main 77 73 -4
fsfreeze_main 81 77 -4
flock_main 318 314 -4
deluser_main 337 333 -4
cp_main 374 370 -4
chown_main 175 171 -4
applet_long_options 4 - -4
xargs_main 894 889 -5
wget_main 2540 2535 -5
udhcpc_main 2767 2762 -5
touch_main 436 431 -5
tar_main 1014 1009 -5
start_stop_daemon_main 1033 1028 -5
sed_main 682 677 -5
script_main 1082 1077 -5
run_parts_main 330 325 -5
rtcwake_main 459 454 -5
od_main 2169 2164 -5
nl_main 201 196 -5
modprobe_main 773 768 -5
mkdir_main 160 155 -5
ls_main 568 563 -5
install_main 773 768 -5
hwclock_main 411 406 -5
getopt_main 622 617 -5
fstrim_main 256 251 -5
env_main 198 193 -5
dumpleases_main 635 630 -5
dpkg_main 3991 3986 -5
diff_main 1355 1350 -5
cryptpw_main 233 228 -5
cpio_main 593 588 -5
conspy_main 1135 1130 -5
chpasswd_main 313 308 -5
adduser_main 887 882 -5
addgroup_main 416 411 -5
ftpgetput_main 351 345 -6
get_terminal_width_height 242 234 -8
expand_main 690 680 -10
static.expand_longopts 18 - -18
static.unexpand_longopts 27 - -27
mkdir_longopts 28 - -28
env_longopts 30 - -30
static.ifenslave_longopts 34 - -34
mv_longopts 46 - -46
static.rmdir_longopts 48 - -48
packed_usage 31739 31687 -52
------------------------------------------------------------------------------
(add/remove: 2/8 grow/shrink: 3/49 up/down: 1352/-1840) Total: -488 bytes
text data bss dec hex filename
915681 485 6880 923046 e15a6 busybox_old
915428 485 6876 922789 e14a5 busybox_unstripped
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Move first two messages to log2 level:
08:46:32.23824 udhcpc: opening raw socket on ifindex 2
08:46:32.23825 udhcpc: got raw socket fd
08:46:32.26354 udhcpc: created raw socket
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
