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Date: Thu, 30 Sep 2021 14:38:41 +0300
From: Nikolay Aleksandrov <razor@...ckwall.org>
To: netdev@...r.kernel.org
Cc: roopa@...dia.com, donaldsharp72@...il.com, dsahern@...il.com,
idosch@...sch.org, Nikolay Aleksandrov <nikolay@...dia.com>
Subject: [PATCH iproute2-next 09/12] ip: nexthop: add cache helpers
From: Nikolay Aleksandrov <nikolay@...dia.com>
Add a static nexthop cache in a hash with 1024 buckets and helpers to
manage it (link, unlink, find, add nexthop, del nexthop). Adding new
nexthops is done by creating a new rtnl handle and using it to retrieve
the nexthop so the helper is safe to use while already reading a
response (i.e. using the global rth).
Signed-off-by: Nikolay Aleksandrov <nikolay@...dia.com>
---
ip/ipnexthop.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++
ip/nh_common.h | 6 ++++
2 files changed, 104 insertions(+)
diff --git a/ip/ipnexthop.c b/ip/ipnexthop.c
index 454c7416e30f..e0f0f78460c9 100644
--- a/ip/ipnexthop.c
+++ b/ip/ipnexthop.c
@@ -34,6 +34,8 @@ enum {
#define RTM_NHA(h) ((struct rtattr *)(((char *)(h)) + \
NLMSG_ALIGN(sizeof(struct nhmsg))))
+static struct hlist_head nh_cache[NH_CACHE_SIZE];
+
static void usage(void) __attribute__((noreturn));
static void usage(void)
@@ -504,6 +506,102 @@ static int __ipnh_get_id(struct rtnl_handle *rthp, __u32 nh_id,
return rtnl_talk(rthp, &req.n, answer);
}
+static struct hlist_head *ipnh_cache_head(__u32 nh_id)
+{
+ nh_id ^= nh_id >> 20;
+ nh_id ^= nh_id >> 10;
+
+ return &nh_cache[nh_id % NH_CACHE_SIZE];
+}
+
+static void ipnh_cache_link_entry(struct nh_entry *nhe)
+{
+ struct hlist_head *head = ipnh_cache_head(nhe->nh_id);
+
+ hlist_add_head(&nhe->nh_hash, head);
+}
+
+static void ipnh_cache_unlink_entry(struct nh_entry *nhe)
+{
+ hlist_del(&nhe->nh_hash);
+}
+
+static struct nh_entry *ipnh_cache_get(__u32 nh_id)
+{
+ struct hlist_head *head = ipnh_cache_head(nh_id);
+ struct nh_entry *nhe;
+ struct hlist_node *n;
+
+ hlist_for_each(n, head) {
+ nhe = container_of(n, struct nh_entry, nh_hash);
+ if (nhe->nh_id == nh_id)
+ return nhe;
+ }
+
+ return NULL;
+}
+
+static int __ipnh_cache_parse_nlmsg(const struct nlmsghdr *n,
+ struct nh_entry *nhe)
+{
+ int err, len;
+
+ len = n->nlmsg_len - NLMSG_SPACE(sizeof(struct nhmsg));
+ if (len < 0) {
+ fprintf(stderr, "BUG: wrong nlmsg len %d\n", len);
+ return -EINVAL;
+ }
+
+ err = ipnh_parse_nhmsg(stderr, NLMSG_DATA(n), len, nhe);
+ if (err) {
+ fprintf(stderr, "Error parsing nexthop: %s\n", strerror(-err));
+ return err;
+ }
+
+ return 0;
+}
+
+static struct nh_entry *ipnh_cache_add(__u32 nh_id)
+{
+ struct rtnl_handle cache_rth = { .fd = -1 };
+ struct nlmsghdr *answer = NULL;
+ struct nh_entry *nhe = NULL;
+
+ if (rtnl_open(&cache_rth, 0) < 0)
+ goto out;
+
+ if (__ipnh_get_id(&cache_rth, nh_id, &answer) < 0)
+ goto out;
+
+ nhe = malloc(sizeof(*nhe));
+ if (!nhe)
+ goto out;
+
+ if (__ipnh_cache_parse_nlmsg(answer, nhe))
+ goto out_free_nhe;
+
+ ipnh_cache_link_entry(nhe);
+
+out:
+ if (answer)
+ free(answer);
+ rtnl_close(&cache_rth);
+
+ return nhe;
+
+out_free_nhe:
+ free(nhe);
+ nhe = NULL;
+ goto out;
+}
+
+static void ipnh_cache_del(struct nh_entry *nhe)
+{
+ ipnh_cache_unlink_entry(nhe);
+ ipnh_destroy_entry(nhe);
+ free(nhe);
+}
+
int print_nexthop(struct nlmsghdr *n, void *arg)
{
struct nhmsg *nhm = NLMSG_DATA(n);
diff --git a/ip/nh_common.h b/ip/nh_common.h
index d9730f45c6fb..ee84d968d8dd 100644
--- a/ip/nh_common.h
+++ b/ip/nh_common.h
@@ -2,6 +2,10 @@
#ifndef __NH_COMMON_H__
#define __NH_COMMON_H__ 1
+#include <list.h>
+
+#define NH_CACHE_SIZE 1024
+
struct nha_res_grp {
__u16 buckets;
__u32 idle_timer;
@@ -10,6 +14,8 @@ struct nha_res_grp {
};
struct nh_entry {
+ struct hlist_node nh_hash;
+
__u32 nh_id;
__u32 nh_oif;
__u32 nh_flags;
--
2.31.1
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