From d34f73f20de8e062ab5a4af720da8b1f9637d11e Mon Sep 17 00:00:00 2001
From: Trekkie Coder <trekkie@netlox.io>
Date: Mon, 15 Jul 2024 17:22:01 +0900
Subject: [PATCH] ecmp load-balancing support

---
 common/llb_dpapi.h      |  7 +++++--
 kernel/llb_kern_l2fwd.c |  2 +-
 kernel/llb_kern_l3fwd.c | 12 ++++++++++--
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/common/llb_dpapi.h b/common/llb_dpapi.h
index bdd28e7..7c37778 100644
--- a/common/llb_dpapi.h
+++ b/common/llb_dpapi.h
@@ -190,9 +190,12 @@ struct dp_rt_l2nh_act {
   __u16 rnh_num;
 };
 
+#define DP_MAX_ACTIVE_PATHS (4)
+
 struct dp_rt_nh_act {
-  __u16 nh_num;
-  __u16 bd; 
+  __u16 nh_num[DP_MAX_ACTIVE_PATHS];
+  __u16 naps;
+  __u16 bd;
   __u32 tid;
   struct dp_rt_l2nh_act l2nh;
 };
diff --git a/kernel/llb_kern_l2fwd.c b/kernel/llb_kern_l2fwd.c
index 88274dc..2c19edb 100644
--- a/kernel/llb_kern_l2fwd.c
+++ b/kernel/llb_kern_l2fwd.c
@@ -53,7 +53,7 @@ dp_do_smac_lkup(void *ctx, struct xfi *xf, void *fc)
 static int __always_inline
 dp_pipe_set_l22_tun_nh(void *ctx, struct xfi *xf, struct dp_rt_nh_act *rnh)
 {
-  xf->pm.nh_num = rnh->nh_num;
+  xf->pm.nh_num = rnh->nh_num[0];
 
   /*
    * We do not set out_bd here. After NH lookup match is
diff --git a/kernel/llb_kern_l3fwd.c b/kernel/llb_kern_l3fwd.c
index 725e8b6..6e3726c 100644
--- a/kernel/llb_kern_l3fwd.c
+++ b/kernel/llb_kern_l3fwd.c
@@ -48,7 +48,7 @@ dp_pipe_set_l32_tun_nh(void *ctx, struct xfi *xf,
                        struct dp_rt_nh_act *rnh)
 {
   struct dp_rt_l2nh_act *nl2;
-  xf->pm.nh_num = rnh->nh_num;
+  xf->pm.nh_num = rnh->nh_num[0];
   /*
    * We do not set out_bd here. After NH lookup match is
    * found and packet tunnel insertion is done, BD is set accordingly
@@ -120,7 +120,15 @@ dp_do_rtops(void *ctx, struct xfi *xf, void *fa_, struct dp_rt_tact *act)
     xf->pm.oport = ra->oport;
   } else if (act->ca.act_type == DP_SET_RT_NHNUM) {
     struct dp_rt_nh_act *rnh = &act->rt_nh;
-    xf->pm.nh_num = rnh->nh_num;
+
+    if (rnh->naps > 1) {
+      int sel = dp_get_pkt_hash(ctx) % rnh->naps;
+      if (sel >= 0 && sel < DP_MAX_ACTIVE_PATHS) {
+        xf->pm.nh_num = rnh->nh_num[sel];
+      }
+    } else {
+      xf->pm.nh_num = rnh->nh_num[0];
+    }
     return dp_do_rt_fwdops(ctx, xf);
   } /*else if (act->ca.act_type == DP_SET_L3RT_TUN_NH) {
 #ifdef HAVE_DP_EXTFC