19903f0d4
Denis Vlasenko
2008-05-21
Subject
udhcpc: simplify renewal of the lease
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Commit Diff GitHub →
networking/udhcp/dhcpc.c+19 -22
| @@ -143,10 +143,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) | |
| uint32_t xid = 0; | |
| uint32_t lease_seconds = 0; /* can be given as 32-bit quantity */ | |
| int packet_num; | |
| - | /* t1, t2... what a wonderful names... */ |
| - | unsigned t1 = t1; /* for gcc */ |
| - | unsigned t2 = t2; |
| - | unsigned timestamp_got_lease = timestamp_got_lease; |
| + | unsigned already_waited_sec; |
| unsigned opt; | |
| int max_fd; | |
| int retval; | |
| @@ -337,6 +334,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) | |
| udhcp_run_script(NULL, "deconfig"); | |
| change_listen_mode(LISTEN_RAW); | |
| packet_num = 0; | |
| + | already_waited_sec = 0; |
| /* Main event loop. select() waits on signal pipe and possibly | |
| * on sockfd. | |
| @@ -353,7 +351,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) | |
| } | |
| max_fd = udhcp_sp_fd_set(&rfds, sockfd); | |
| - | tv.tv_sec = timeout; |
| + | tv.tv_sec = timeout - already_waited_sec; |
| tv.tv_usec = 0; | |
| retval = 0; /* If we already timed out, fall through, else... */ | |
| if (tv.tv_sec > 0) { | |
| @@ -373,6 +371,9 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) | |
| * resend discover/renew/whatever | |
| */ | |
| if (retval == 0) { | |
| + | /* We will restart wait afresh in any case */ |
| + | already_waited_sec = 0; |
| + | |
| switch (state) { | |
| case INIT_SELECTING: | |
| if (packet_num < discover_retries) { | |
| @@ -420,33 +421,29 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) | |
| packet_num = 0; | |
| continue; | |
| case BOUND: | |
| - | /* Lease is starting to run out, time to enter renewing state */ |
| + | /* Half of the lease passed, time to enter renewing state */ |
| change_listen_mode(LISTEN_KERNEL); | |
| DEBUG("Entering renew state"); | |
| state = RENEWING; | |
| /* fall right through */ | |
| case RENEWING: | |
| - | /* Either set a new T1, or enter REBINDING state */ |
| - | if ((t2 - t1) > (lease_seconds / (4*60*60) + 1)) { |
| + | if (timeout > 60) { |
| /* send a request packet */ | |
| send_renew(xid, server_addr, requested_ip); /* unicast */ | |
| - | t1 += (t2 - t1) / 2; |
| - | timeout = t1 - ((unsigned)monotonic_sec() - timestamp_got_lease); |
| + | timeout >>= 1; |
| continue; | |
| } | |
| /* Timed out, enter rebinding state */ | |
| DEBUG("Entering rebinding state"); | |
| state = REBINDING; | |
| - | timeout = (t2 - t1); |
| continue; | |
| case REBINDING: | |
| /* Lease is *really* about to run out, | |
| * try to find DHCP server using broadcast */ | |
| - | if ((lease_seconds - t2) > (lease_seconds / (4*60*60) + 1)) { |
| + | if (timeout > 0) { |
| /* send a request packet */ | |
| send_renew(xid, 0, requested_ip); /* broadcast */ | |
| - | t2 += (lease_seconds - t2) / 2; |
| - | timeout = t2 - ((unsigned)monotonic_sec() - timestamp_got_lease); |
| + | timeout >>= 1; |
| continue; | |
| } | |
| /* Timed out, enter init state */ | |
| @@ -454,7 +451,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) | |
| udhcp_run_script(NULL, "deconfig"); | |
| change_listen_mode(LISTEN_RAW); | |
| state = INIT_SELECTING; | |
| - | timeout = 0; |
| + | /*timeout = 0; - already is */ |
| packet_num = 0; | |
| continue; | |
| /* case RELEASED: */ | |
| @@ -477,7 +474,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) | |
| /* If this packet will turn out to be unrelated/bogus, | |
| * we will go back and wait for next one. | |
| * Be sure timeout is properly decreased. */ | |
| - | timeout -= (unsigned)monotonic_sec() - timestamp_before_wait; |
| + | already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait; |
| if (len == -1) { /* error is severe, reopen socket */ | |
| DEBUG("error on read, %s, reopening socket", strerror(errno)); | |
| @@ -523,6 +520,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) | |
| state = REQUESTING; | |
| timeout = 0; | |
| packet_num = 0; | |
| + | already_waited_sec = 0; |
| } | |
| continue; | |
| case RENEW_REQUESTED: | |
| @@ -538,6 +536,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) | |
| /* can be misaligned, thus memcpy */ | |
| memcpy(&lease_seconds, temp, 4); | |
| lease_seconds = ntohl(lease_seconds); | |
| + | lease_seconds &= 0x0fffffff; /* paranoia: must not be negative */ |
| } | |
| #if ENABLE_FEATURE_UDHCPC_ARPING | |
| if (opt & OPT_a) { | |
| @@ -557,20 +556,16 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) | |
| requested_ip = 0; | |
| timeout = tryagain_timeout; | |
| packet_num = 0; | |
| + | already_waited_sec = 0; |
| continue; /* back to main loop */ | |
| } | |
| } | |
| #endif | |
| /* enter bound state */ | |
| - | t1 = lease_seconds / 2; |
| - | |
| - | /* little fixed point for n * .875 */ |
| - | t2 = (lease_seconds * 7) >> 3; |
| + | timeout = lease_seconds / 2; |
| temp_addr.s_addr = packet.yiaddr; | |
| bb_info_msg("Lease of %s obtained, lease time %u", | |
| inet_ntoa(temp_addr), (unsigned)lease_seconds); | |
| - | timestamp_got_lease = monotonic_sec(); |
| - | timeout = t1; |
| requested_ip = packet.yiaddr; | |
| udhcp_run_script(&packet, | |
| ((state == RENEWING || state == REBINDING) ? "renew" : "bound")); | |
| @@ -585,6 +580,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) | |
| if (!client_config.foreground) | |
| client_background(); | |
| + | already_waited_sec = 0; |
| continue; /* back to main loop */ | |
| } | |
| if (*message == DHCPNAK) { | |
| @@ -599,6 +595,7 @@ int udhcpc_main(int argc ATTRIBUTE_UNUSED, char **argv) | |
| requested_ip = 0; | |
| timeout = 0; | |
| packet_num = 0; | |
| + | already_waited_sec = 0; |
| } | |
| continue; | |
| /* case BOUND, RELEASED: - ignore all packets */ | |