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From bc252caa54fcfb2e9fd0ddb01ebaa50192e85c38 Mon Sep 17 00:00:00 2001
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From: Alex Williamson <alex.williamson@redhat.com>
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Date: Wed, 21 Oct 2015 11:18:40 +0200
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Subject: Use spec compliant timeouts
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Message-id: <20150428212403.31299.29391.stgit@gimli.home>
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Patchwork-id: 64951
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O-Subject: [RHEL7.2 ipxe PATCH 2/2] [dhcp][RHEL-only] Use spec compliant timeouts
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Bugzilla: 1196352
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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RH-Acked-by: Gerd Hoffmann <kraxel@redhat.com>
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RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
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Use local config to override iPXE's abbreviated DHCP timeouts using
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the recommended values for spec compliance.  This matches the state
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of RHEL6 gPXE DHCP timeouts after bz968474 + bz1206042
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Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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(cherry picked from commit 7038f41c0131d263de5165b416500009acdbf550)
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---
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 src/config/local/.gitignore |  1 -
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 src/config/local/dhcp.h     | 62 +++++++++++++++++++++++++++++++++++++++++++++
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 2 files changed, 62 insertions(+), 1 deletion(-)
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 delete mode 100644 src/config/local/.gitignore
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 create mode 100644 src/config/local/dhcp.h
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diff --git a/src/config/local/dhcp.h b/src/config/local/dhcp.h
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new file mode 100644
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index 0000000..83df5b8
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--- /dev/null
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+++ b/src/config/local/dhcp.h
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@@ -0,0 +1,62 @@
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+/*
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+ * Downstream localization
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+ *
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+ * For RHEL, use spec compliant DHCP timeouts (bz1196352)
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+ */
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+
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+/*
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+ * PXE spec defines timeouts of 4, 8, 16, 32 seconds
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+ */
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+#undef DHCP_DISC_START_TIMEOUT_SEC
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+#define DHCP_DISC_START_TIMEOUT_SEC 4
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+#undef DHCP_DISC_END_TIMEOUT_SEC
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+#define DHCP_DISC_END_TIMEOUT_SEC   32
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+
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+/*
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+ * Elapsed time used for early break waiting for ProxyDHCP, this therefore
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+ * needs to be less than the cumulative time for the first 2 timeouts.
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+ */
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+#undef DHCP_DISC_PROXY_TIMEOUT_SEC
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+#define DHCP_DISC_PROXY_TIMEOUT_SEC 11
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+
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+/*
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+ * Approximate PXE spec requirement using minimum timeout (0.25s) for
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+ * timeouts of 0.25, 0.5, 1, 2, 4
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+ */
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+#undef DHCP_REQ_START_TIMEOUT_SEC
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+#define DHCP_REQ_START_TIMEOUT_SEC  0
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+#undef DHCP_REQ_END_TIMEOUT_SEC
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+#define DHCP_REQ_END_TIMEOUT_SEC    4
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+
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+/*
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+ * Same as normal request phase, except non-fatal, so we extend the timer
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+ * to 8 and set the early timeout to an elapsed time value that causes a
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+ * break after the 4 second timeout.  At least that's what we'd like to do,
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+ * but our timer operates at 18Hz and has a minimum resolution of 7 cycles.
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+ * Therefore the above quarter-second starting timeout looks more like
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+ * 0.39s, 0.78s, 1.56s, 3.11s, 6.22s.  If we had an ideal timer, we could
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+ * set the timeout to 7s (0.25 + 0.5 + 1 + 2 + 4 = 7.75s) and exit without
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+ * failure when the timer rolls over to 8s.  With our timer, we get 0.39 +
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+ * 0.78 + 1.56 + 3.11 = 5.84s.  The next timeout would take us to 12.06s
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+ * (+6.22).  That seems like a long time to wait for an optional reply, so
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+ * we reduce the early timeout to 5s to exit before the timer exceeds the
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+ * max and causes a failure.  This still adds one extra cycle vs the
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+ * upstream defaults.
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+ */
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+#undef DHCP_PROXY_START_TIMEOUT_SEC
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+#define DHCP_PROXY_START_TIMEOUT_SEC        0
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+#undef DHCP_PROXY_END_TIMEOUT_SEC
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+#define DHCP_PROXY_END_TIMEOUT_SEC  8
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+#undef DHCP_REQ_PROXY_TIMEOUT_SEC
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+#define DHCP_REQ_PROXY_TIMEOUT_SEC  5
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+
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+/*
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+ * Same as above, retry each server using our approximation of standard
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+ * timeouts and exit before timer induced failure.
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+ */
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+#undef PXEBS_START_TIMEOUT_SEC
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+#define PXEBS_START_TIMEOUT_SEC             0
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+#undef PXEBS_END_TIMEOUT_SEC
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+#define PXEBS_END_TIMEOUT_SEC               8
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+#undef PXEBS_MAX_TIMEOUT_SEC
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+#define PXEBS_MAX_TIMEOUT_SEC               5
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-- 
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1.8.3.1
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