From b3530e3e683cd6d66140004f50e7325f55053381 Mon Sep 17 00:00:00 2001
From: Christian Deacon <christian@moddingcommunity.com>
Date: Sun, 12 Nov 2023 21:35:22 +0000
Subject: [PATCH] Use per CPU array map for filter rules to increase
 performance.

---
 src/xdpfw.c      | 12 ++++++++++--
 src/xdpfw_kern.c |  2 +-
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/xdpfw.c b/src/xdpfw.c
index 2e97029..971a183 100644
--- a/src/xdpfw.c
+++ b/src/xdpfw.c
@@ -43,7 +43,7 @@ void signalHndl(int tmp)
 */
 void updatefilters(struct config *cfg)
 {
-    // Loop through all filters and delete the map.
+    // Loop through all filters and delete the map. We do this in the case rules were edited and were put out of order since the key doesn't uniquely map to a specific rule.
     for (__u8 i = 0; i < MAX_FILTERS; i++)
     {
         __u32 key = i;
@@ -60,8 +60,16 @@ void updatefilters(struct config *cfg)
             break;
         }
 
+        // Create value array (max CPUs in size) since we're using a per CPU map.
+        struct filter filter[MAX_CPUS];
+
+        for (int j = 0; j < MAX_CPUS; j++)
+        {
+            filter[j] = cfg->filters[i];
+        }
+
         // Attempt to update BPF map.
-        if (bpf_map_update_elem(filtersmap, &i, &cfg->filters[i], BPF_ANY) == -1)
+        if (bpf_map_update_elem(filtersmap, &i, &filter, BPF_ANY) == -1)
         {
             fprintf(stderr, "Error updating BPF item #%d\n", i);
         }
diff --git a/src/xdpfw_kern.c b/src/xdpfw_kern.c
index 24a6701..81933f1 100644
--- a/src/xdpfw_kern.c
+++ b/src/xdpfw_kern.c
@@ -29,7 +29,7 @@ struct
 
 struct 
 {
-    __uint(type, BPF_MAP_TYPE_ARRAY);
+    __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
     __uint(max_entries, MAX_FILTERS);
     __type(key, __u32);
     __type(value, struct filter);