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From 33a9ff0045adfa605832187e570dbe1374ceb22e Mon Sep 17 00:00:00 2001
From: Mark Stapp <mjs@voltanet.io>
Date: Tue, 28 Jan 2020 11:00:42 -0500
Subject: [PATCH] zebra: add config to disable use of kernel nexthops
Add a config that disables use of kernel-level nexthop ids.
Currently, zebra always uses nexthop ids if the kernel supports
them.
Signed-off-by: Mark Stapp <mjs@voltanet.io>
---
zebra/rt_netlink.c | 20 ++++++++++++++++----
zebra/zebra_nhg.c | 18 ++++++++++++++++++
zebra/zebra_nhg.h | 10 +++++++++-
zebra/zebra_vty.c | 18 ++++++++++++++++++
4 files changed, 61 insertions(+), 5 deletions(-)
diff --git a/zebra/rt_netlink.c b/zebra/rt_netlink.c
index 2abcd6ef2a..705536595b 100644
--- a/zebra/rt_netlink.c
+++ b/zebra/rt_netlink.c
@@ -75,6 +75,10 @@
static vlanid_t filter_vlan = 0;
+/* We capture whether the current kernel supports nexthop ids; by
+ * default, we'll use them if possible. There's also a configuration
+ * available to _disable_ use of kernel nexthops.
+ */
static bool supports_nh;
struct gw_family_t {
@@ -86,6 +90,12 @@ struct gw_family_t {
static const char ipv4_ll_buf[16] = "169.254.0.1";
static struct in_addr ipv4_ll;
+/* Helper to control use of kernel-level nexthop ids */
+static bool kernel_nexthops_supported(void)
+{
+ return (supports_nh && zebra_nhg_kernel_nexthops_enabled());
+}
+
/*
* The ipv4_ll data structure is used for all 5549
* additions to the kernel. Let's figure out the
@@ -1628,7 +1638,7 @@ static int netlink_route_multipath(int cmd, struct zebra_dplane_ctx *ctx)
RTA_PAYLOAD(rta));
}
- if (supports_nh) {
+ if (kernel_nexthops_supported()) {
/* Kernel supports nexthop objects */
addattr32(&req.n, sizeof(req), RTA_NH_ID,
dplane_ctx_get_nhe_id(ctx));
@@ -1943,7 +1953,7 @@ static int netlink_nexthop(int cmd, struct zebra_dplane_ctx *ctx)
size_t req_size = sizeof(req);
/* Nothing to do if the kernel doesn't support nexthop objects */
- if (!supports_nh)
+ if (!kernel_nexthops_supported())
return 0;
label_buf[0] = '\0';
@@ -2504,8 +2514,10 @@ int netlink_nexthop_read(struct zebra_ns *zns)
* this kernel must support them.
*/
supports_nh = true;
- else if (IS_ZEBRA_DEBUG_KERNEL)
- zlog_debug("Nexthop objects not supported on this kernel");
+
+ if (IS_ZEBRA_DEBUG_KERNEL || IS_ZEBRA_DEBUG_NHG)
+ zlog_debug("Nexthop objects %ssupported on this kernel",
+ supports_nh ? "" : "not ");
return ret;
}
diff --git a/zebra/zebra_nhg.c b/zebra/zebra_nhg.c
index cbeb73aed4..62c478cf85 100644
--- a/zebra/zebra_nhg.c
+++ b/zebra/zebra_nhg.c
@@ -49,6 +49,9 @@ DEFINE_MTYPE_STATIC(ZEBRA, NHG_CTX, "Nexthop Group Context");
/* id counter to keep in sync with kernel */
uint32_t id_counter;
+/* */
+static bool g_nexthops_enabled = true;
+
static struct nhg_hash_entry *depends_find(const struct nexthop *nh,
afi_t afi);
static void depends_add(struct nhg_connected_tree_head *head,
@@ -2004,3 +2007,18 @@ void zebra_nhg_sweep_table(struct hash *hash)
{
hash_iterate(hash, zebra_nhg_sweep_entry, NULL);
}
+
+/* Global control to disable use of kernel nexthops, if available. We can't
+ * force the kernel to support nexthop ids, of course, but we can disable
+ * zebra's use of them, for testing e.g. By default, if the kernel supports
+ * nexthop ids, zebra uses them.
+ */
+void zebra_nhg_enable_kernel_nexthops(bool set)
+{
+ g_nexthops_enabled = set;
+}
+
+bool zebra_nhg_kernel_nexthops_enabled(void)
+{
+ return g_nexthops_enabled;
+}
diff --git a/zebra/zebra_nhg.h b/zebra/zebra_nhg.h
index c2e173e094..4d001944b7 100644
--- a/zebra/zebra_nhg.h
+++ b/zebra/zebra_nhg.h
@@ -153,6 +153,13 @@ struct nhg_ctx {
enum nhg_ctx_status status;
};
+/* Global control to disable use of kernel nexthops, if available. We can't
+ * force the kernel to support nexthop ids, of course, but we can disable
+ * zebra's use of them, for testing e.g. By default, if the kernel supports
+ * nexthop ids, zebra uses them.
+ */
+void zebra_nhg_enable_kernel_nexthops(bool set);
+bool zebra_nhg_kernel_nexthops_enabled(void);
/**
* NHE abstracted tree functions.
@@ -227,4 +234,5 @@ extern void zebra_nhg_sweep_table(struct hash *hash);
/* Nexthop resolution processing */
struct route_entry; /* Forward ref to avoid circular includes */
extern int nexthop_active_update(struct route_node *rn, struct route_entry *re);
-#endif
+
+#endif /* __ZEBRA_NHG_H__ */
diff --git a/zebra/zebra_vty.c b/zebra/zebra_vty.c
index 78001da170..866b38b47e 100644
--- a/zebra/zebra_vty.c
+++ b/zebra/zebra_vty.c
@@ -1410,6 +1410,19 @@ DEFPY (show_nexthop_group,
return CMD_SUCCESS;
}
+DEFPY_HIDDEN(nexthop_group_use_enable,
+ nexthop_group_use_enable_cmd,
+ "[no] zebra nexthop kernel enable",
+ NO_STR
+ ZEBRA_STR
+ "Nexthop configuration \n"
+ "Configure use of kernel nexthops\n"
+ "Enable kernel nexthops\n")
+{
+ zebra_nhg_enable_kernel_nexthops(!no);
+ return CMD_SUCCESS;
+}
+
DEFUN (no_ip_nht_default_route,
no_ip_nht_default_route_cmd,
"no ip nht resolve-via-default",
@@ -3121,6 +3134,10 @@ static int config_write_protocol(struct vty *vty)
/* Include dataplane info */
dplane_config_write_helper(vty);
+ /* Include nexthop-group config */
+ if (!zebra_nhg_kernel_nexthops_enabled())
+ vty_out(vty, "no zebra nexthop kernel enable\n");
+
return 1;
}
@@ -3492,6 +3509,7 @@ void zebra_vty_init(void)
install_element(CONFIG_NODE, &no_zebra_workqueue_timer_cmd);
install_element(CONFIG_NODE, &zebra_packet_process_cmd);
install_element(CONFIG_NODE, &no_zebra_packet_process_cmd);
+ install_element(CONFIG_NODE, &nexthop_group_use_enable_cmd);
install_element(VIEW_NODE, &show_nexthop_group_cmd);
install_element(VIEW_NODE, &show_interface_nexthop_group_cmd);