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>
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>
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>
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>
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>
Commit b8b72f02 removed all padding from DHCP packets
to fix operation with buggy servers which can't handle
maximum sized packets. But it introduced a regression
with buggy routers which drop DHCP packets smaller
than 300 bytes (i.e. 342 byte ethernet packets).
Add back some padding to work around.
function old new delta
udhcp_send_kernel_packet 268 292 +24
udhcp_send_raw_packet 462 473 +11
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 35/0) Total: 35 bytes
Signed-off-by: Johannes Stezenbach <js@sig21.net>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This change retains "or later" state! No licensing _changes_ here,
only form is adjusted (article, space between "GPL" and "v2" and so on).
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
also gets rid of ether-aton's static buffer in ether-wake:
text data bss dec hexfilename
838664 441 7572 846677 ceb55busybox_old
838650 441 7564 846655 ceb3fbusybox_unstripped
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
udhcpc: make UDP packet sending the same as raw sending in regards
to error messages. Minor code size shrink. Total size grows due
to added messages:
text data bss dec hex filename
770312 683 7244 778239 bdfff busybox_old
770327 683 7244 778254 be00e busybox_unstripped
