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>
Kconfig-language.txt was deleted in commit 4fa499a17b back in 2006.
Move to docs/ as suggested by Xabier Oneca:
http://lists.busybox.net/pipermail/busybox/2014-May/080914.html
Also update references to it everywhere.
Signed-off-by: Kartik Agaram <akkartik@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This is to avoid parsing garbage past packet's actual end.
Also const-ize params to a few functions.
function old new delta
d6_run_script_no_option - 12 +12
option_to_env 791 798 +7
d6_run_script 253 255 +2
perform_d6_release 95 93 -2
udhcpc6_main 2596 2592 -4
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 2/2 up/down: 21/-6) Total: 15 bytes
Signed-off-by: David Decotigny <ddecotig@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Add support for the PXELINUX options 209 ("ConfigFile") and 210
("PathPrefix") in the DHCPv6 client.
See also: RFC5071, "Dynamic Host Configuration Protocol Options Used by
PXELINUX".
Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Add support for 'bootfile-url' and 'bootfile-params' as defined by
RFC5970 "DHCPv6 Options for Network Boot".
Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Add string_option_to_env() to easily generate environment variables for
known simple options.
Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
trim() modifies the string in place if needed and returns a pointer to
the end of the resulting string. Update udhcp_str2optset() so it no
longer sets the value of 'val' to the return value of trim().
Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
EINTR _should_ only happen on two signals we trap, and safe_poll
_should_ work here just fine, but there were kernel bugs where spurious EINTRs
happen (e.g. on ptrace attach). Be safe.
function old new delta
udhcpd_main 1437 1468 +31
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>
