udhcpc: emit "correct" secs field

In theory, sending secs set to constant zero should be ok too.
But some bleeping servers can actually be configured to answer ONLY
if secs is bigger than a preset value (!!)
http://developer.apple.com/library/mac/#documentation/Darwin/Reference/ManPages/man8/bootpd.8.html
grep for "reply_threshold_seconds"

function                                             old     new   delta
udhcpc_main                                         2573    2623     +50

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index e9a8412042dc7d6aa06042293971458d3982c28b..ca82d37e60d09c1e02ed5f648ba73659aea1556f 100644 (file)
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -407,11 +407,19 @@ static ALWAYS_INLINE uint32_t random_xid(void)
 /* Initialize the packet with the proper defaults */
 static void init_packet(struct dhcp_packet *packet, char type)
 {
+       uint16_t secs;
+
        /* Fill in: op, htype, hlen, cookie fields; message type option: */
        udhcp_init_header(packet, type);
 
        packet->xid = random_xid();
 
+       client_config.last_secs = monotonic_sec();
+       if (client_config.first_secs == 0)
+               client_config.first_secs = client_config.last_secs;
+       secs = client_config.last_secs - client_config.first_secs;
+       packet->secs = htons(secs);
+
        memcpy(packet->chaddr, client_config.client_mac, 6);
        if (client_config.clientid)
                udhcp_add_binary_option(packet, client_config.clientid);
@@ -848,6 +856,7 @@ static void change_listen_mode(int new_mode)
        /* else LISTEN_NONE: sockfd stays closed */
 }
 
+/* Called only on SIGUSR1 */
 static void perform_renew(void)
 {
        bb_info_msg("Performing a DHCP renew");
@@ -1260,6 +1269,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                        case BOUND:
                                /* 1/2 lease passed, enter renewing state */
                                state = RENEWING;
+                               client_config.first_secs = 0; /* make secs field count from 0 */
                                change_listen_mode(LISTEN_KERNEL);
                                log1("Entering renew state");
                                /* fall right through */
@@ -1299,6 +1309,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                bb_info_msg("Lease lost, entering init state");
                                udhcp_run_script(NULL, "deconfig");
                                state = INIT_SELECTING;
+                               client_config.first_secs = 0; /* make secs field count from 0 */
                                /*timeout = 0; - already is */
                                packet_num = 0;
                                continue;
@@ -1315,6 +1326,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                /* note: udhcp_sp_read checks FD_ISSET before reading */
                switch (udhcp_sp_read(&rfds)) {
                case SIGUSR1:
+                       client_config.first_secs = 0; /* make secs field count from 0 */
                        perform_renew();
                        if (state == RENEW_REQUESTED)
                                goto case_RENEW_REQUESTED;
@@ -1446,6 +1458,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                                        udhcp_run_script(NULL, "deconfig");
                                                change_listen_mode(LISTEN_RAW);
                                                state = INIT_SELECTING;
+                                               client_config.first_secs = 0; /* make secs field count from 0 */
                                                requested_ip = 0;
                                                timeout = tryagain_timeout;
                                                packet_num = 0;
@@ -1493,6 +1506,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
                                change_listen_mode(LISTEN_RAW);
                                sleep(3); /* avoid excessive network traffic */
                                state = INIT_SELECTING;
+                               client_config.first_secs = 0; /* make secs field count from 0 */
                                requested_ip = 0;
                                timeout = 0;
                                packet_num = 0;

diff --git a/networking/udhcp/dhcpc.h b/networking/udhcp/dhcpc.h
index 9ef053a1beb418dce1f8fe5f8674572fb9116d82..2b3599120f09e25d20462d5c9586202201eefb1c 100644 (file)
--- a/networking/udhcp/dhcpc.h
+++ b/networking/udhcp/dhcpc.h
@@ -21,6 +21,9 @@ struct client_config_t {
        uint8_t *vendorclass;           /* Optional vendor class-id to use */
        uint8_t *hostname;              /* Optional hostname to use */
        uint8_t *fqdn;                  /* Optional fully qualified domain name to use */
+
+       uint16_t first_secs;
+       uint16_t last_secs;
 } FIX_ALIASING;
 
 /* server_config sits in 1st half of bb_common_bufsiz1 */