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pping: More aggressive map cleanup

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Add conditions that allows removing old flow and timestamp entries
sooner.

For flow map, have added conditions that allow unopened flows and ICMP
flows to be removed earlier than open TCP flows (currently both set to
30 sec instead of 300 sec).

For timestamp entries, allow them to be removed if they're more than
TIMESTAMP_RTT_LIFETIME (currently 8) times higher than the flow's
sRTT.

Signed-off-by: Simon Sundberg <simon.sundberg@kau.se>
This commit is contained in:
Simon Sundberg
2022-02-17 14:11:40 +01:00
parent 72404b6767
commit f22025f716
1 changed files with 27 additions and 9 deletions
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36
pping/pping_kern.c
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@@ -33,9 +33,11 @@
#define WARN_MAP_FULL_INTERVAL 1000000000UL
// Time before map entry is considered old and can safetly be removed
#define TIMESTAMP_LIFETIME (10 * NS_PER_SECOND)
#define FLOW_LIFETIME (300 * NS_PER_SECOND)
#define TIMESTAMP_LIFETIME (10 * NS_PER_SECOND) // Clear any timestamp older than this
#define TIMESTAMP_RTT_LIFETIME 8 // Clear timestamp once it is this many times older than RTT
#define FLOW_LIFETIME (300 * NS_PER_SECOND) // Clear any flow that's been inactive this long
#define ICMP_FLOW_LIFETIME (30 * NS_PER_SECOND) // Clear any ICMP flows if they're inactive this long
#define UNOPENED_FLOW_LIFETIME (30 * NS_PER_SECOND) // Clear out flows that have not seen a response after this long
/*
* Structs for map iteration programs
@@ -811,9 +813,11 @@ SEC("iter/bpf_map_elem")
int tsmap_cleanup(struct bpf_iter__bpf_map_elem *ctx)
{
struct packet_id local_pid;
struct flow_state *f_state;
struct packet_id *pid = ctx->key;
__u64 *timestamp = ctx->value;
__u64 now = bpf_ktime_get_ns();
__u64 rtt;
debug_update_mapclean_stats(ctx, &events, !ctx->key || !ctx->value,
ctx->meta->seq_num, now,
@@ -821,12 +825,17 @@ int tsmap_cleanup(struct bpf_iter__bpf_map_elem *ctx)
if (!pid || !timestamp)
return 0;
if (now <= *timestamp)
return 0;
if (now > *timestamp && now - *timestamp > TIMESTAMP_LIFETIME) {
/* Seems like the key for map lookup operations must be
on the stack, so copy pid to local_pid. */
__builtin_memcpy(&local_pid, pid, sizeof(local_pid));
/* Seems like the key for map lookup operations must be
on the stack, so copy pid to local_pid. */
__builtin_memcpy(&local_pid, pid, sizeof(local_pid));
f_state = bpf_map_lookup_elem(&flow_state, &local_pid.flow);
rtt = f_state ? f_state->srtt : 0;
if ((rtt && now - *timestamp > rtt * TIMESTAMP_RTT_LIFETIME) ||
now - *timestamp > TIMESTAMP_LIFETIME) {
if (bpf_map_delete_elem(&packet_ts, &local_pid) == 0)
debug_increment_timeoutdel(PPING_MAP_PACKETTS);
}
@@ -843,6 +852,7 @@ int flowmap_cleanup(struct bpf_iter__bpf_map_elem *ctx)
struct flow_event fe;
__u64 now = bpf_ktime_get_ns();
bool has_opened;
__u64 age;
debug_update_mapclean_stats(ctx, &events, !ctx->key || !ctx->value,
ctx->meta->seq_num, now,
@@ -850,9 +860,17 @@ int flowmap_cleanup(struct bpf_iter__bpf_map_elem *ctx)
if (!flow || !f_state)
return 0;
if (now < f_state->last_timestamp)
return 0;
if (now > f_state->last_timestamp &&
now - f_state->last_timestamp > FLOW_LIFETIME) {
// Check if flow is too old for unopned/ICMP/other flow type
age = now - f_state->last_timestamp;
has_opened = f_state->has_opened;
if ((!has_opened && age > UNOPENED_FLOW_LIFETIME) ||
((flow->proto == IPPROTO_ICMP || flow->proto == IPPROTO_ICMPV6) &&
age > ICMP_FLOW_LIFETIME) ||
age > FLOW_LIFETIME) {
__builtin_memcpy(&local_flow, flow, sizeof(local_flow));
has_opened = f_state->has_opened;