mirror of https://github.com/ipxe/ipxe.git
[dhcp] Limit maximum number of DHCP discovery deferrals
For switches which remain permanently in the non-forwarding state (or which erroneously report a non-forwarding state), ensure that iPXE will eventually give up waiting for the link to become unblocked. Originally-fixed-by: Wissam Shoukair <wissams@mellanox.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>pull/41/head
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@ -24,6 +24,12 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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//#define DHCP_DISC_START_TIMEOUT_SEC 4 /* as per PXE spec */
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//#define DHCP_DISC_END_TIMEOUT_SEC 32 /* as per PXE spec */
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/*
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* Maximum number of discovery deferrals due to blocked links
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* (e.g. from non-forwarding STP ports)
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*/
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#define DHCP_DISC_MAX_DEFERRALS 60
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/*
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* ProxyDHCP offers are given precedence by continue to wait for them
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* after a valid DHCPOFFER is received. We'll wait through this
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@ -444,7 +444,8 @@ static void dhcp_discovery_expired ( struct dhcp_session *dhcp ) {
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unsigned long elapsed = ( currticks() - dhcp->start );
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/* If link is blocked, defer DHCP discovery (and reset timeout) */
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if ( netdev_link_blocked ( dhcp->netdev ) ) {
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if ( netdev_link_blocked ( dhcp->netdev ) &&
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( dhcp->count <= DHCP_DISC_MAX_DEFERRALS ) ) {
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DBGC ( dhcp, "DHCP %p deferring discovery\n", dhcp );
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dhcp->start = currticks();
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start_timer_fixed ( &dhcp->timer,
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@ -1115,7 +1116,7 @@ static int dhcp_tx ( struct dhcp_session *dhcp ) {
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* session state into packet traces. Useful for extracting
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* debug information from non-debug builds.
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*/
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dhcppkt.dhcphdr->secs = htons ( ( ++(dhcp->count) << 2 ) |
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dhcppkt.dhcphdr->secs = htons ( ( dhcp->count << 2 ) |
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( dhcp->offer.s_addr ? 0x02 : 0 ) |
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( dhcp->proxy_offer ? 0x01 : 0 ) );
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@ -1259,6 +1260,9 @@ static void dhcp_timer_expired ( struct retry_timer *timer, int fail ) {
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return;
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}
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/* Increment transmission counter */
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dhcp->count++;
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/* Handle timer expiry based on current state */
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dhcp->state->expired ( dhcp );
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}
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