udhcpd: add option for tweaking arpping
Some clients have a very short timeout for sending the DHCP
DISCOVER, shorter than the arpping timeout of 2000 milliseconds
that udhcpd uses by default.
This patch allows tweaking the timeout, or disabling of arpping
altogether, at the risk of handing out addresses which are
already in use.
function old new delta
udhcpd_main 1460 1501 +41
udhcpc_main 2814 2851 +37
packed_usage 29957 29974 +17
arpping 477 493 +16
find_free_or_expired_nip 161 174 +13
send_offer 285 292 +7
nobody_responds_to_arp 85 89 +4
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 7/0 up/down: 135/0) Total: 135 bytes
Signed-off-by: Michel Stam <m.stam@fugro.nl>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index e468b7b..35e7c20 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -54,7 +54,7 @@
"foreground\0" No_argument "f"
"background\0" No_argument "b"
"broadcast\0" No_argument "B"
- IF_FEATURE_UDHCPC_ARPING("arping\0" No_argument "a")
+ IF_FEATURE_UDHCPC_ARPING("arping\0" Optional_argument "a")
IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
;
#endif
@@ -1150,7 +1150,7 @@
//usage:# define IF_UDHCP_VERBOSE(...)
//usage:#endif
//usage:#define udhcpc_trivial_usage
-//usage: "[-fbq"IF_UDHCP_VERBOSE("v")IF_FEATURE_UDHCPC_ARPING("a")"RB] [-t N] [-T SEC] [-A SEC/-n]\n"
+//usage: "[-fbq"IF_UDHCP_VERBOSE("v")"RB]"IF_FEATURE_UDHCPC_ARPING(" [-a[MSEC]]")" [-t N] [-T SEC] [-A SEC/-n]\n"
//usage: " [-i IFACE]"IF_FEATURE_UDHCP_PORT(" [-P PORT]")" [-s PROG] [-p PIDFILE]\n"
//usage: " [-oC] [-r IP] [-V VENDOR] [-F NAME] [-x OPT:VAL]... [-O OPT]..."
//usage:#define udhcpc_full_usage "\n"
@@ -1174,7 +1174,7 @@
//usage: )
//usage: "\n -S,--syslog Log to syslog too"
//usage: IF_FEATURE_UDHCPC_ARPING(
-//usage: "\n -a,--arping Use arping to validate offered address"
+//usage: "\n -a[MSEC],--arping[=MSEC] Validate offered address with ARP ping"
//usage: )
//usage: "\n -r,--request IP Request this IP address"
//usage: "\n -o,--no-default-options Don't request any options (unless -O is given)"
@@ -1211,7 +1211,7 @@
//usage: )
//usage: "\n -S Log to syslog too"
//usage: IF_FEATURE_UDHCPC_ARPING(
-//usage: "\n -a Use arping to validate offered address"
+//usage: "\n -a[MSEC] Validate offered address with ARP ping"
//usage: )
//usage: "\n -r IP Request this IP address"
//usage: "\n -o Don't request any options (unless -O is given)"
@@ -1238,6 +1238,7 @@
{
uint8_t *message;
const char *str_V, *str_h, *str_F, *str_r;
+ IF_FEATURE_UDHCPC_ARPING(const char *str_a = "2000";)
IF_FEATURE_UDHCP_PORT(char *str_P;)
void *clientid_mac_ptr;
llist_t *list_O = NULL;
@@ -1252,6 +1253,7 @@
int timeout; /* must be signed */
unsigned already_waited_sec;
unsigned opt;
+ IF_FEATURE_UDHCPC_ARPING(unsigned arpping_ms;)
int max_fd;
int retval;
fd_set rfds;
@@ -1269,7 +1271,7 @@
IF_LONG_OPTS(applet_long_options = udhcpc_longopts;)
opt = getopt32(argv, "CV:H:h:F:i:np:qRr:s:T:t:SA:O:ox:fB"
USE_FOR_MMU("b")
- IF_FEATURE_UDHCPC_ARPING("a")
+ IF_FEATURE_UDHCPC_ARPING("a::")
IF_FEATURE_UDHCP_PORT("P:")
"v"
, &str_V, &str_h, &str_h, &str_F
@@ -1278,6 +1280,7 @@
, &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
, &list_O
, &list_x
+ IF_FEATURE_UDHCPC_ARPING(, &str_a)
IF_FEATURE_UDHCP_PORT(, &str_P)
IF_UDHCP_VERBOSE(, &dhcp_verbose)
);
@@ -1309,6 +1312,7 @@
SERVER_PORT = CLIENT_PORT - 1;
}
#endif
+ IF_FEATURE_UDHCPC_ARPING(arpping_ms = xatou(str_a);)
while (list_O) {
char *optstr = llist_pop(&list_O);
unsigned n = bb_strtou(optstr, NULL, 0);
@@ -1726,7 +1730,8 @@
NULL,
(uint32_t) 0,
client_config.client_mac,
- client_config.interface)
+ client_config.interface,
+ arpping_ms)
) {
bb_info_msg("Offered address is in use "
"(got ARP reply), declining");