b8175a021b
Add a proto_dhcp_restart() handler that re-acquires the DHCP lease via a single ubus call, releasing the previous lease and triggering a fresh DHCPDISCOVER without bouncing the interface. The re-acquire is implemented by sending SIGHUP to udhcpc, which releases the current lease (if any) and immediately transitions the state machine to INIT_SELECTING so the next main-loop iteration sends a fresh DHCPDISCOVER. A single signal thus expresses 'release this lease and get a new one' without exiting the client, so upstream watchdogs (e.g. a DNS-health monitor) can request a clean re-lease without tearing down the interface. Signed-off-by: John Crispin <john@phrozen.org> Signed-off-by: Felix Fietkau <nbd@nbd.name>
48 lines
1.7 KiB
Diff
48 lines
1.7 KiB
Diff
From: John Crispin <john@phrozen.org>
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Date: Wed, 15 Apr 2026 16:15:38 +0200
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Subject: [PATCH] udhcpc: treat SIGHUP as release + rediscover
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Add a SIGHUP handler to udhcpc that releases the current lease (if any)
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and immediately transitions the state machine to INIT_SELECTING so the
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next main-loop iteration sends a fresh DHCPDISCOVER. This lets a single
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signal express 'release this lease and get a new one' without exiting
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the client, so upstream watchdogs (e.g. a DNS-health monitor) can
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request a clean re-lease without tearing down the interface.
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Signed-off-by: John Crispin <john@phrozen.org>
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---
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--- a/networking/udhcp/dhcpc.c
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+++ b/networking/udhcp/dhcpc.c
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@@ -1606,6 +1606,22 @@ int udhcpc_main(int argc UNUSED_PARAM, c
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/* ^^^ switches to LISTEN_NONE */
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timeout = INT_MAX;
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continue;
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+ case SIGHUP:
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+ bb_info_msg("received SIGHUP, restarting DHCP session");
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+ /* release the current lease if we have one */
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+ if (client_data.state != INIT_SELECTING
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+ && client_data.state != RELEASED)
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+ perform_release(server_id, requested_ip);
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+ /* drop any cached offer, kick the state machine into
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+ * INIT_SELECTING so the next iteration sends a fresh
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+ * DHCPDISCOVER */
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+ change_listen_mode(LISTEN_NONE);
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+ server_id = 0;
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+ requested_ip = 0;
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+ packet_num = 0;
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+ client_data.state = INIT_SELECTING;
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+ timeout = 0;
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+ continue;
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case SIGTERM:
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bb_info_msg("received %s", "SIGTERM");
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goto ret0;
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--- a/networking/udhcp/signalpipe.c
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+++ b/networking/udhcp/signalpipe.c
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@@ -58,6 +58,7 @@ void FAST_FUNC udhcp_sp_setup(void)
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bb_signals(0
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+ (1 << SIGUSR1)
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+ (1 << SIGUSR2)
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+ + (1 << SIGHUP)
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+ (1 << SIGTERM)
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, signal_handler);
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}
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