olsrd: import patch to prevent olsr storms

Fixes:
https://github.com/OLSR/olsrd/issues/106

Signed-off-by: Nick Hainke <vincent@systemli.org>

diff --git a/olsrd/patches/102-limit-valid-+ve-sequence-number-diff-to-avoid-storms.patch b/olsrd/patches/102-limit-valid-+ve-sequence-number-diff-to-avoid-storms.patch
new file mode 100644 (file)
index 0000000..8105fc6
--- /dev/null
+++ b/olsrd/patches/102-limit-valid-+ve-sequence-number-diff-to-avoid-storms.patch
@@ -0,0 +1,79 @@
+From 08faae831d9facf8bd42c66ba046ab081645efe1 Mon Sep 17 00:00:00 2001
+From: Tim <tim@aredn-builder.home>
+Date: Mon, 6 Sep 2021 20:22:42 +0000
+Subject: [PATCH] Limit valid +ve sequence number diff to avoid storms
+
+---
+ net/olsrd/patches/009-olsrd-seqnr.patch | 66 +++++++++++++++++++++++++
+ 1 file changed, 66 insertions(+)
+ create mode 100644 net/olsrd/patches/009-olsrd-seqnr.patch
+
+--- /dev/null
++++ b/net/olsrd/patches/009-olsrd-seqnr.patch
+@@ -0,0 +1,66 @@
++--- a/src/duplicate_set.c
+++++ b/src/duplicate_set.c
++@@ -70,7 +70,7 @@ void olsr_cleanup_duplicates(union olsr_
++ 
++   entry = (struct dup_entry *)avl_find(&duplicate_set, orig);
++   if (entry != NULL) {
++-    entry->too_low_counter = DUP_MAX_TOO_LOW - 2;
+++    entry->out_of_bounds_counter = DUP_MAX_OUT_OF_BOUNDS - 2;
++   }
++ }
++ 
++@@ -82,7 +82,7 @@ olsr_create_duplicate_entry(void *ip, ui
++   if (entry != NULL) {
++     memcpy(&entry->ip, ip, olsr_cnf->ip_version == AF_INET ? sizeof(entry->ip.v4) : sizeof(entry->ip.v6));
++     entry->seqnr = seqnr;
++-    entry->too_low_counter = 0;
+++    entry->out_of_bounds_counter = 0;
++     entry->avl.key = &entry->ip;
++     entry->array = 0;
++   }
++@@ -160,12 +160,12 @@ olsr_message_is_duplicate(union olsr_mes
++   }
++ 
++   diff = olsr_seqno_diff(seqnr, entry->seqnr);
++-  if (diff < -31) {
++-    entry->too_low_counter++;
+++  if (diff < -31 || diff > DUP_SEQNR_DIFF_HIGH_LIMIT) {
+++    entry->out_of_bounds_counter++;
++ 
++-    // client did restart with a lower number ?
++-    if (entry->too_low_counter > DUP_MAX_TOO_LOW) {
++-      entry->too_low_counter = 0;
+++    // client did restart with a too low or too high number ?
+++    if (entry->out_of_bounds_counter > DUP_MAX_OUT_OF_BOUNDS) {
+++      entry->out_of_bounds_counter = 0;
++       entry->seqnr = seqnr;
++       entry->array = 1;
++       return false;             /* start with a new sequence number, so NO duplicate */
++@@ -174,7 +174,7 @@ olsr_message_is_duplicate(union olsr_mes
++     return true;                /* duplicate ! */
++   }
++ 
++-  entry->too_low_counter = 0;
+++  entry->out_of_bounds_counter = 0;
++   if (diff <= 0) {
++     uint32_t bitmask = 1u << ((uint32_t) (-diff));
++ 
++--- a/src/duplicate_set.h
+++++ b/src/duplicate_set.h
++@@ -54,13 +54,14 @@
++ #define DUPLICATE_CLEANUP_INTERVAL 15000
++ #define DUPLICATE_CLEANUP_JITTER 25
++ #define DUPLICATE_VTIME 120000
++-#define DUP_MAX_TOO_LOW 16
+++#define DUP_MAX_OUT_OF_BOUNDS 16
+++#define DUP_SEQNR_DIFF_HIGH_LIMIT 0x2000
++ 
++ struct dup_entry {
++   struct avl_node avl;
++   union olsr_ip_addr ip;
++   uint16_t seqnr;
++-  uint16_t too_low_counter;
+++  uint16_t out_of_bounds_counter;
++   uint32_t array;
++   uint32_t valid_until;
++ };