86 lines
3.3 KiB
Diff
86 lines
3.3 KiB
Diff
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From bed605f5bd8524779b3cf3d3e02baf06a76f4054 Mon Sep 17 00:00:00 2001
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From: Beniamino Galvani <bgalvani@redhat.com>
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Date: Wed, 10 May 2017 16:17:48 +0200
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Subject: [PATCH] dhcp: don't add route to DHCP4 server
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This basically reverts commit 31fe84e46773 "core: Add host route for
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DHCP4 server if outside assigned subnet (bgo #721767)" because the
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additional route added by NM does more harm than good.
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First, the code does not consider routes pushed by the server and thus
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it can add a route conflicting with the ones from the network
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administrator.
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Second, there is no specification on what a DHCP client should do when
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the server is not reachable via unicast, and adding arbitrary logic
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into the client is likely to break things in specific cases. If
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network administrators want to make the DHCP server reachable from a
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client in a different subnet, they should push proper routes with the
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lease.
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In any case, if the DHCP server is not reachable through unicast,
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before the lease expiration (after timeout T2) the client will resort
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to broadcast and so there won't be any network disruption; the renewal
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will only happen at a later time.
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Fixes: 31fe84e467732463eabc8f70c2a419008e7a227c
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https://bugzilla.redhat.com/show_bug.cgi?id=1448987
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(cherry picked from commit 36e97f5d7beba7ab5446c2b7c6c22523b1bca476)
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(cherry picked from commit cbf5a776f72d1895405b71f45a74cf4fe9046dae)
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---
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src/dhcp/nm-dhcp-utils.c | 37 -------------------------------------
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1 file changed, 37 deletions(-)
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diff --git a/src/dhcp/nm-dhcp-utils.c b/src/dhcp/nm-dhcp-utils.c
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index e020ca3..e55a21b 100644
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--- a/src/dhcp/nm-dhcp-utils.c
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+++ b/src/dhcp/nm-dhcp-utils.c
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@@ -450,43 +450,6 @@ nm_dhcp_utils_ip4_config_from_options (int ifindex,
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}
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}
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- /*
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- * RFC 2132, section 9.7
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- * DHCP clients use the contents of the 'server identifier' field
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- * as the destination address for any DHCP messages unicast to
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- * the DHCP server.
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- *
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- * Some ISP's provide leases from central servers that are on
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- * different subnets that the address offered. If the host
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- * does not configure the interface as the default route, the
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- * dhcp server may not be reachable via unicast, and a host
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- * specific route is needed.
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- **/
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- str = g_hash_table_lookup (options, "dhcp_server_identifier");
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- if (str) {
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- if (inet_pton (AF_INET, str, &tmp_addr) > 0) {
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-
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- _LOG2I (LOGD_DHCP4, iface, " server identifier %s", str);
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- if ( nm_utils_ip4_address_clear_host_address(tmp_addr, address.plen) != nm_utils_ip4_address_clear_host_address(address.address, address.plen)
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- && !nm_ip4_config_get_direct_route_for_host (ip4_config, tmp_addr)) {
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- /* DHCP server not on assigned subnet and the no direct route was returned. Add route */
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- NMPlatformIP4Route route = { 0 };
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-
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- route.network = tmp_addr;
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- route.plen = 32;
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- /* this will be a device route if gwaddr is 0 */
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- route.gateway = gwaddr;
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- route.rt_source = NM_IP_CONFIG_SOURCE_DHCP;
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- route.metric = priority;
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- nm_ip4_config_add_route (ip4_config, &route);
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- _LOG2D (LOGD_IP, iface, "adding route for server identifier: %s",
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- nm_platform_ip4_route_to_string (&route, NULL, 0));
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- }
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- }
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- else
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- _LOG2W (LOGD_DHCP4, iface, "ignoring invalid server identifier '%s'", str);
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- }
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-
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str = g_hash_table_lookup (options, "dhcp_lease_time");
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if (str) {
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address.lifetime = address.preferred = strtoul (str, NULL, 10);
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--
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2.9.3
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