From 268a52a9344b84a8170eac712dcf7f75d0c35732 Mon Sep 17 00:00:00 2001
From: mzz2017 <2017@duck.com>
Date: Wed, 1 Feb 2023 11:10:41 +0800
Subject: [PATCH] fix: remove unsupported (on old kernel) bpf_skb_adjust_room
 flag BPF_F_ADJ_ROOM_NO_CSUM_RESET

---
 cmd/run.go                      |  5 ++++-
 component/control/kern/tproxy.c | 22 ++++++++++++----------
 2 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/cmd/run.go b/cmd/run.go
index 2a735cf..9adfcc2 100644
--- a/cmd/run.go
+++ b/cmd/run.go
@@ -21,6 +21,9 @@ var (
 		Use:   "run",
 		Short: "Run dae in the foreground",
 		Run: func(cmd *cobra.Command, args []string) {
+			if cfgFile == "" {
+				logrus.Fatalln("Argument \"--config\" or \"-c\" is required but not provided.")
+			}
 			if err := Run(); err != nil {
 				logrus.Fatalln(err)
 			}
@@ -29,7 +32,7 @@ var (
 )
 
 func init() {
-	runCmd.PersistentFlags().StringVarP(&cfgFile, "config", "c", "config.dae", "config file")
+	runCmd.PersistentFlags().StringVarP(&cfgFile, "config", "c", "", "config file")
 }
 
 func Run() (err error) {
diff --git a/component/control/kern/tproxy.c b/component/control/kern/tproxy.c
index 4dd74a4..e5c3bef 100644
--- a/component/control/kern/tproxy.c
+++ b/component/control/kern/tproxy.c
@@ -689,9 +689,8 @@ static __always_inline int encap_after_udp_hdr(struct __sk_buff *skb,
     return ret;
   }
   // Add room for new udp payload header.
-  if ((ret = bpf_skb_adjust_room(skb, newhdrlen, BPF_ADJ_ROOM_NET,
-                                 BPF_F_ADJ_ROOM_NO_CSUM_RESET))) {
-    bpf_printk("UDP ADJUST ROOM: %d", ret);
+  if ((ret = bpf_skb_adjust_room(skb, newhdrlen, BPF_ADJ_ROOM_NET, 0))) {
+    bpf_printk("UDP ADJUST ROOM(encap): %d", ret);
     return ret;
   }
   // Move the new room to the front of the UDP payload.
@@ -776,9 +775,8 @@ static __always_inline int decap_after_udp_hdr(struct __sk_buff *skb,
   }
 
   // Adjust room to decap the header.
-  if ((ret = bpf_skb_adjust_room(skb, -decap_hdrlen, BPF_ADJ_ROOM_NET,
-                                 BPF_F_ADJ_ROOM_NO_CSUM_RESET))) {
-    bpf_printk("UDP ADJUST ROOM: %d", ret);
+  if ((ret = bpf_skb_adjust_room(skb, -decap_hdrlen, BPF_ADJ_ROOM_NET, 0))) {
+    bpf_printk("UDP ADJUST ROOM(decap): %d", ret);
     return ret;
   }
 
@@ -1191,8 +1189,10 @@ int tproxy_ingress(struct __sk_buff *skb) {
       // Rewrite to control plane.
 
       // Encap a header to transmit fullcone tuple.
-      encap_after_udp_hdr(skb, ipversion, ihl, ipv4_tot_len, &new_hdr,
-                          sizeof(new_hdr));
+      if ((ret = encap_after_udp_hdr(skb, ipversion, ihl, ipv4_tot_len,
+                                     &new_hdr, sizeof(new_hdr)))) {
+        return TC_ACT_SHOT;
+      }
 
       // Rewrite udp dst ip.
       // bpf_printk("rewrite dst ip from %pI4", &ori_dst.ip);
@@ -1692,8 +1692,10 @@ int tproxy_wan_egress(struct __sk_buff *skb) {
         };
 
         // Encap a header to transmit fullcone tuple.
-        encap_after_udp_hdr(skb, ipversion, ihl, ipv4_tot_len, &new_hdr,
-                            sizeof(new_hdr));
+        if ((ret = encap_after_udp_hdr(skb, ipversion, ihl, ipv4_tot_len,
+                                       &new_hdr, sizeof(new_hdr)))) {
+          return TC_ACT_SHOT;
+        }
 
         // Redirect from egress to ingress.
         if ((ret = bpf_redirect(skb->ifindex, BPF_F_INGRESS)) == TC_ACT_SHOT) {