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udhcpc[6]: fix "untangle timeout and remaining lease" fallout

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As reported in bug 13776, before this fix the renew never times out.

function                                             old     new   delta
udhcpc_main                                         2541    2585     +44
udhcpc6_main                                        2567    2558      -9
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 44/-9)              Total: 35 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2021-06-01 00:19:03 +02:00
parent 7de0ab21d9
commit 687f41f10b
2 changed files with 47 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
networking/udhcp/d6_dhcpc.c
View File

@@ -1356,14 +1356,17 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
log1("waiting %u seconds", timeout);
diff = (unsigned)monotonic_sec();
retval = poll(pfds, 2, timeout * 1000);
diff = (unsigned)monotonic_sec() - diff;
lease_remaining -= diff;
if (lease_remaining < 0)
lease_remaining = 0;
timeout -= diff;
if (timeout < 0)
timeout = 0;
if (retval < 0) {
/* EINTR? A signal was caught, don't panic */
if (errno == EINTR) {
diff = (unsigned)monotonic_sec() - diff;
lease_remaining -= diff;
if (lease_remaining < 0)
lease_remaining = 0;
timeout -= diff;
continue;
}
/* Else: an error occured, panic! */
@@ -1455,7 +1458,6 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
case_RENEW_REQUESTED:
case RENEWING:
if (packet_num < 3) {
packet_num++;
/* send an unicast renew request */
/* Sometimes observed to fail (EADDRNOTAVAIL) to bind
* a new UDP socket for sending inside send_renew.
@@ -1471,23 +1473,26 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
send_d6_renew(xid, &srv6_buf, requested_ipv6);
timeout = discover_timeout;
/* ^^^ used to be = lease_remaining / 2 - WAY too long */
packet_num++;
continue;
}
/* Timed out, enter rebinding state */
log1s("entering rebinding state");
client_data.state = REBINDING;
packet_num = 0;
/* fall right through */
case REBINDING:
/* Switch to bcast receive */
change_listen_mode(LISTEN_RAW);
/* Lease is *really* about to run out,
* try to find DHCP server using broadcast */
if (lease_remaining > 0) {
if (lease_remaining > 0 && packet_num < 3) {
if (opt & OPT_l)
send_d6_info_request(xid);
else /* send a broadcast renew request */
send_d6_renew(xid, /*server_ipv6:*/ NULL, requested_ipv6);
timeout = discover_timeout;
packet_num++;
continue;
}
/* Timed out, enter init state */
@@ -1809,12 +1814,9 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
start = monotonic_sec();
d6_run_script(packet.d6_options, packet_end,
(client_data.state == REQUESTING ? "bound" : "renew"));
timeout = (unsigned)lease_remaining / 2;
timeout -= (unsigned)monotonic_sec() - start;
packet_num = 0;
client_data.state = BOUND;
change_listen_mode(LISTEN_NONE);
lease_remaining -= (unsigned)monotonic_sec() - start;
if (lease_remaining < 0)
lease_remaining = 0;
if (opt & OPT_q) { /* quit after lease */
goto ret0;
}
@@ -1827,6 +1829,12 @@ int udhcpc6_main(int argc UNUSED_PARAM, char **argv)
opt = ((opt & ~OPT_b) | OPT_f);
}
#endif
// BOUND_for_half_lease:
timeout = (unsigned)lease_remaining / 2;
client_data.state = BOUND;
change_listen_mode(LISTEN_NONE);
packet_num = 0;
continue; /* back to main loop */
}
continue;

43
networking/udhcp/dhcpc.c
View File

@@ -1417,14 +1417,17 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
log1("waiting %u seconds", timeout);
diff = (unsigned)monotonic_sec();
retval = poll(pfds, 2, timeout * 1000);
diff = (unsigned)monotonic_sec() - diff;
lease_remaining -= diff;
if (lease_remaining < 0)
lease_remaining = 0;
timeout -= diff;
if (timeout < 0)
timeout = 0;
if (retval < 0) {
/* EINTR? A signal was caught, don't panic */
if (errno == EINTR) {
diff = (unsigned)monotonic_sec() - diff;
lease_remaining -= diff;
if (lease_remaining < 0)
lease_remaining = 0;
timeout -= diff;
continue;
}
/* Else: an error occurred, panic! */
@@ -1513,7 +1516,6 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
case_RENEW_REQUESTED:
case RENEWING:
if (packet_num < 3) {
packet_num++;
/* send an unicast renew request */
/* Sometimes observed to fail (EADDRNOTAVAIL) to bind
* a new UDP socket for sending inside send_renew.
@@ -1526,6 +1528,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
if (send_renew(xid, server_addr, requested_ip) >= 0) {
timeout = discover_timeout;
/* ^^^ used to be = lease_remaining / 2 - WAY too long */
packet_num++;
continue;
}
/* else: error sending.
@@ -1534,21 +1537,26 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
* which wasn't reachable (and probably did not exist).
*/
}
//TODO: if 3 renew's failed (no reply) but remaining lease is large,
//it might make sense to make a large pause (~1 hour?) and try later?
//TODO: if 3 renew's failed (no reply) but remaining lease is large enough,
//it might make sense to go back to BOUND and try later? a-la
// if (lease_remaining > 30) goto BOUND_for_half_lease;
//If we do that, "packet_num < 3" test below might be superfluous
//(lease_remaining will run out anyway)
/* Timed out or error, enter rebinding state */
log1s("entering rebinding state");
client_data.state = REBINDING;
packet_num = 0;
/* fall right through */
case REBINDING:
/* Switch to bcast receive */
change_listen_mode(LISTEN_RAW);
/* Lease is *really* about to run out,
* try to find DHCP server using broadcast */
if (lease_remaining > 0) {
if (lease_remaining > 0 && packet_num < 3) {
/* send a broadcast renew request */
send_renew(xid, 0 /*INADDR_ANY*/, requested_ip);
timeout = discover_timeout;
packet_num++;
continue;
}
/* Timed out, enter init state */
@@ -1773,13 +1781,9 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
/* enter bound state */
start = monotonic_sec();
udhcp_run_script(&packet, client_data.state == REQUESTING ? "bound" : "renew");
timeout = (unsigned)lease_remaining / 2;
//TODO: why / 2?
timeout -= (unsigned)monotonic_sec() - start;
packet_num = 0;
client_data.state = BOUND;
change_listen_mode(LISTEN_NONE);
lease_remaining -= (unsigned)monotonic_sec() - start;
if (lease_remaining < 0)
lease_remaining = 0;
if (opt & OPT_q) { /* quit after lease */
goto ret0;
}
@@ -1792,9 +1796,14 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
opt = ((opt & ~OPT_b) | OPT_f);
}
#endif
// BOUND_for_half_lease:
timeout = (unsigned)lease_remaining / 2;
client_data.state = BOUND;
change_listen_mode(LISTEN_NONE);
/* make future renew packets use different xid */
/* xid = random_xid(); ...but why bother? */
packet_num = 0;
continue; /* back to main loop */
}
if (*message == DHCPNAK) {