A recent commit added condition to "route_table_parse__" function that
causes it to throw an error when parsing route without "nexthop
information" (either RTA_OIF, RTA_GATEWAY, RTA_VIA or RTA_MULTIPATH). While
this requirement is reasonable for regular routes, there are some route types
that don't need nexthop. We intend to use one of these types,
(RTN_BLACKHOLE)[0], in OVN for route advertising .
This change does not enforce the above-mentioned condition for those special
route types that don't require "nexthop information".
v2:
* Ensure that the list of nexthops is cleared if the route does not have
them.
* The function for determining whether a route requires nexthop now takes
route_type (unsigned char) as an argument directly. Previously it
took a pointer to rtmsg struct.
* The patch is rebased on top of the in-flight patch series by Frode[1]
* Fixed typos.
[0] https://mail.openvswitch.org/pipermail/ovs-dev/2025-January/419383.html
[1]
https://patchwork.ozlabs.org/project/openvswitch/patch/[email protected]/
CC: Frode Nordahl <[email protected]>
Fixes: 91fc51106cfe ("route-table: Support parsing multipath routes.")
Signed-off-by: Martin Kalcok <[email protected]>
---
lib/route-table.c | 28 ++++++++++++++++++++++++++--
1 file changed, 26 insertions(+), 2 deletions(-)
diff --git a/lib/route-table.c b/lib/route-table.c
index 6dfb364a4..e5fb7008f 100644
--- a/lib/route-table.c
+++ b/lib/route-table.c
@@ -226,6 +226,23 @@ route_table_reset(void)
}
}
+/* Returns true if the given route requires nexthop information (output
+ * interface, nexthop IP, ...). Returns false for special route types
+ * that don't need this information. */
+static bool
+route_type_needs_nexthop(unsigned char rtmsg_type route_type) {
+ switch (route_type) {
+ case RTN_BLACKHOLE:
+ case RTN_THROW:
+ case RTN_UNREACHABLE:
+ case RTN_PROHIBIT:
+ return false;
+ default:
+ return true;
+ }
+}
+
+
static int
route_table_parse__(struct ofpbuf *buf, size_t ofs,
const struct nlmsghdr *nlmsg,
@@ -450,13 +467,20 @@ route_table_parse__(struct ofpbuf *buf, size_t ofs,
ofpbuf_uninit(&mp_buf);
}
}
- if (!attrs[RTA_OIF] && !attrs[RTA_GATEWAY]
- && !attrs[RTA_VIA] && !attrs[RTA_MULTIPATH]) {
+ if (route_type_needs_nexthop(rtm->rtm_type) && !attrs[RTA_OIF]
+ && !attrs[RTA_GATEWAY] && !attrs[RTA_VIA]
+ && !attrs[RTA_MULTIPATH]) {
VLOG_DBG_RL(&rl, "route message needs an RTA_OIF, RTA_GATEWAY, "
"RTA_VIA or RTA_MULTIPATH attribute");
goto error_out;
}
/* Add any additional RTA attribute processing before RTA_MULTIPATH. */
+
+ /* Ensure that the change->rd->nexthops list is cleared in case that
+ * the route does not need a next hop. */
+ if (!route_type_needs_nexthop(rtm->rtm_type)) {
+ route_data_destroy_nexthops__(&change->rd);
+ }
} else {
VLOG_DBG_RL(&rl, "received unparseable rtnetlink route message");
goto error_out;
base-commit: caed64d1685409d1f9b53b35621a08ad6588200c
prerequisite-patch-id: 9d606dcf57f9213291028029f2a71a43f346ce1e
prerequisite-patch-id: b61606e7f32fede1bd34248957f67d72040be326
prerequisite-patch-id: 907ead49b46ccf4b2e81e9f49f535788e592348b
--
2.43.0
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