6 files changed, 39 insertions, 21 deletions

diff --git a/networking/udhcp/arpping.c b/networking/udhcp/arpping.c
index b43e52e96..fad2283c3 100644
--- a/networking/udhcp/arpping.c
+++ b/networking/udhcp/arpping.c
@@ -39,7 +39,8 @@ int FAST_FUNC arpping(uint32_t test_nip,
                 const uint8_t *safe_mac,
                 uint32_t from_ip,
                 uint8_t *from_mac,
-                const char *interface)
+                const char *interface,
+                unsigned timeo)
 {
         int timeout_ms;
         struct pollfd pfd[1];
@@ -48,6 +49,9 @@ int FAST_FUNC arpping(uint32_t test_nip,
         struct sockaddr addr;   /* for interface name */
         struct arpMsg arp;
 
+        if (!timeo)
+                return 1;
+
         s = socket(PF_PACKET, SOCK_PACKET, htons(ETH_P_ARP));
         if (s == -1) {
                 bb_perror_msg(bb_msg_can_not_create_raw_socket);
@@ -83,7 +87,7 @@ int FAST_FUNC arpping(uint32_t test_nip,
         }
 
         /* wait for arp reply, and check it */
-        timeout_ms = 2000;
+        timeout_ms = (int)timeo;
         do {
                 typedef uint32_t aliased_uint32_t FIX_ALIASING;
                 int r;
@@ -124,7 +128,7 @@ int FAST_FUNC arpping(uint32_t test_nip,
                  * this is more under/overflow-resistant
                  * (people did see overflows here when system time jumps):
                  */
-        } while ((unsigned)timeout_ms <= 2000);
+        } while ((unsigned)timeout_ms <= timeo);
 
  ret:
         close(s);
diff --git a/networking/udhcp/common.h b/networking/udhcp/common.h
index e5e0f2599..d20659e2f 100644
--- a/networking/udhcp/common.h
+++ b/networking/udhcp/common.h
@@ -311,7 +311,8 @@ int arpping(uint32_t test_nip,
                 const uint8_t *safe_mac,
                 uint32_t from_ip,
                 uint8_t *from_mac,
-                const char *interface) FAST_FUNC;
+                const char *interface,
+                unsigned timeo) FAST_FUNC;
 
 /* note: ip is a pointer to an IPv6 in network order, possibly misaliged */
 int sprint_nip6(char *dest, /*const char *pre,*/ const uint8_t *ip) FAST_FUNC;
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index e468b7bbb..35e7c2070 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -54,7 +54,7 @@ static const char udhcpc_longopts[] ALIGN1 =
         "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 @@ static void client_background(void)
 //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 @@ static void client_background(void)
 //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 @@ static void client_background(void)
 //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 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
 {
         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 udhcpc_main(int argc UNUSED_PARAM, char **argv)
         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 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
         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 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                 , &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 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                 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 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                                         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");
diff --git a/networking/udhcp/dhcpd.c b/networking/udhcp/dhcpd.c
index a1a7f6b57..4b3ed240c 100644
--- a/networking/udhcp/dhcpd.c
+++ b/networking/udhcp/dhcpd.c
@@ -28,6 +28,7 @@
 //usage:     "\n        -f      Run in foreground"
 //usage:     "\n        -S      Log to syslog too"
 //usage:     "\n        -I ADDR Local address"
+//usage:     "\n        -a MSEC Timeout for ARP ping (default 2000)"
 //usage:        IF_FEATURE_UDHCP_PORT(
 //usage:     "\n        -P N    Use port N (default 67)"
 //usage:        )
@@ -148,7 +149,8 @@ static uint32_t select_lease_time(struct dhcp_packet *packet)
 static NOINLINE void send_offer(struct dhcp_packet *oldpacket,
                 uint32_t static_lease_nip,
                 struct dyn_lease *lease,
-                uint8_t *requested_ip_opt)
+                uint8_t *requested_ip_opt,
+                unsigned arpping_ms)
 {
         struct dhcp_packet packet;
         uint32_t lease_time_sec;
@@ -187,7 +189,7 @@ static NOINLINE void send_offer(struct dhcp_packet *oldpacket,
                 }
                 else {
                         /* Otherwise, find a free IP */
-                        packet.yiaddr = find_free_or_expired_nip(oldpacket->chaddr);
+                        packet.yiaddr = find_free_or_expired_nip(oldpacket->chaddr, arpping_ms);
                 }
 
                 if (!packet.yiaddr) {
@@ -304,6 +306,8 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
         unsigned opt;
         struct option_set *option;
         char *str_I = str_I;
+        const char *str_a = "2000";
+        unsigned arpping_ms;
         IF_FEATURE_UDHCP_PORT(char *str_P;)
 
 #if ENABLE_FEATURE_UDHCP_PORT
@@ -314,9 +318,10 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
         opt_complementary = "vv";
 #endif
-        opt = getopt32(argv, "fSI:v"
+        opt = getopt32(argv, "fSI:va:"
                 IF_FEATURE_UDHCP_PORT("P:")
                 , &str_I
+                , &str_a
                 IF_FEATURE_UDHCP_PORT(, &str_P)
                 IF_UDHCP_VERBOSE(, &dhcp_verbose)
                 );
@@ -336,11 +341,13 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
                 free(lsa);
         }
 #if ENABLE_FEATURE_UDHCP_PORT
-        if (opt & 16) { /* -P */
+        if (opt & 32) { /* -P */
                 SERVER_PORT = xatou16(str_P);
                 CLIENT_PORT = SERVER_PORT + 1;
         }
 #endif
+        arpping_ms = xatou(str_a);
+
         /* Would rather not do read_config before daemonization -
          * otherwise NOMMU machines will parse config twice */
         read_config(argv[0] ? argv[0] : DHCPD_CONF_FILE);
@@ -498,7 +505,7 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
                 case DHCPDISCOVER:
                         log1("Received DISCOVER");
 
-                        send_offer(&packet, static_lease_nip, lease, requested_ip_opt);
+                        send_offer(&packet, static_lease_nip, lease, requested_ip_opt, arpping_ms);
                         break;
 
                 case DHCPREQUEST:
diff --git a/networking/udhcp/dhcpd.h b/networking/udhcp/dhcpd.h
index a77724f20..183e7e24c 100644
--- a/networking/udhcp/dhcpd.h
+++ b/networking/udhcp/dhcpd.h
@@ -100,7 +100,7 @@ struct dyn_lease *add_lease(
 int is_expired_lease(struct dyn_lease *lease) FAST_FUNC;
 struct dyn_lease *find_lease_by_mac(const uint8_t *mac) FAST_FUNC;
 struct dyn_lease *find_lease_by_nip(uint32_t nip) FAST_FUNC;
-uint32_t find_free_or_expired_nip(const uint8_t *safe_mac) FAST_FUNC;
+uint32_t find_free_or_expired_nip(const uint8_t *safe_mac, unsigned arpping_ms) FAST_FUNC;
 
 
 /* Config file parser will pass static lease info to this function
diff --git a/networking/udhcp/leases.c b/networking/udhcp/leases.c
index c5b60b108..745340ad3 100644
--- a/networking/udhcp/leases.c
+++ b/networking/udhcp/leases.c
@@ -112,7 +112,7 @@ struct dyn_lease* FAST_FUNC find_lease_by_nip(uint32_t nip)
 }
 
 /* Check if the IP is taken; if it is, add it to the lease table */
-static int nobody_responds_to_arp(uint32_t nip, const uint8_t *safe_mac)
+static int nobody_responds_to_arp(uint32_t nip, const uint8_t *safe_mac, unsigned arpping_ms)
 {
         struct in_addr temp;
         int r;
@@ -120,7 +120,8 @@ static int nobody_responds_to_arp(uint32_t nip, const uint8_t *safe_mac)
         r = arpping(nip, safe_mac,
                         server_config.server_nip,
                         server_config.server_mac,
-                        server_config.interface);
+                        server_config.interface,
+                        arpping_ms);
         if (r)
                 return r;
 
@@ -132,7 +133,7 @@ static int nobody_responds_to_arp(uint32_t nip, const uint8_t *safe_mac)
 }
 
 /* Find a new usable (we think) address */
-uint32_t FAST_FUNC find_free_or_expired_nip(const uint8_t *safe_mac)
+uint32_t FAST_FUNC find_free_or_expired_nip(const uint8_t *safe_mac, unsigned arpping_ms)
 {
         uint32_t addr;
         struct dyn_lease *oldest_lease = NULL;
@@ -177,7 +178,7 @@ uint32_t FAST_FUNC find_free_or_expired_nip(const uint8_t *safe_mac)
                 lease = find_lease_by_nip(nip);
                 if (!lease) {
 //TODO: DHCP servers do not always sit on the same subnet as clients: should *ping*, not arp-ping!
-                        if (nobody_responds_to_arp(nip, safe_mac))
+                        if (nobody_responds_to_arp(nip, safe_mac, arpping_ms))
                                 return nip;
                 } else {
                         if (!oldest_lease || lease->expires < oldest_lease->expires)
@@ -194,7 +195,7 @@ uint32_t FAST_FUNC find_free_or_expired_nip(const uint8_t *safe_mac)
 
         if (oldest_lease
          && is_expired_lease(oldest_lease)
-         && nobody_responds_to_arp(oldest_lease->lease_nip, safe_mac)
+         && nobody_responds_to_arp(oldest_lease->lease_nip, safe_mac, arpping_ms)
         ) {
                 return oldest_lease->lease_nip;
         }