Update UDP bit logic + cleanup

Signed-off-by: astoycos <[email protected]>
redhat-et · Nov 3, 2022 · 36719a2 · 36719a2
1 parent 559040f
commit 36719a2
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Showing 5 changed files with 13 additions and 10 deletions.
diff --git a/bpf/xdp_udp.bpf.c b/bpf/xdp_udp.bpf.c
@@ -83,6 +83,8 @@ static __always_inline __u16 udp_checksum(struct iphdr *ip, struct udphdr * udp,
         // Last byte
         if (i + 1 == udp_len) {
           csum_total += (*(__u8 *)buf);
+          // Verifier fails without this print statement, I have no Idea why :/
+          bpf_printk("Adding last byte %X to csum", (*(__u8 *)buf));
         } else { 
           csum_total += *buf;
         }
@@ -197,10 +199,12 @@ int xdp_prog_func(struct xdp_md *ctx) {
   bpf_printk("new dest hwaddr %x:%x:%x:%x:%x:%x", eth->h_dest[0], eth->h_dest[1], eth->h_dest[2], eth->h_dest[3], eth->h_dest[4], eth->h_dest[5]);
 
   ip->check = iph_csum(ip);
-
+  
   udp->check = 0;
   if (!bk->nocksum){
-    udp->check = udp_checksum(ip, udp, data_end);
+    int tmp_check = udp_checksum(ip, udp, data_end);
+    bpf_printk("Manual Cksum: %X Diff Cksum %X", tmp_check, udp_csum_diff(udp));
+    udp->check = tmp_check;
   }
 
   bpf_printk("destination interface index %d", bk->ifindex);

diff --git a/userspace-go/bpf_bpfeb.o b/userspace-go/bpf_bpfeb.o
diff --git a/userspace-go/bpf_bpfel.o b/userspace-go/bpf_bpfel.o
diff --git a/userspace-go/userspace-go b/userspace-go/userspace-go
diff --git a/userspace-go/xdp_udp.go b/userspace-go/xdp_udp.go
@@ -33,13 +33,7 @@ func main() {
 	if err != nil {
 		log.Fatalf("lookup network iface %s: %s", ifaceName, err)
 	}
-
-	// opts := ebpf.CollectionOptions{
-	// 	Programs: ebpf.ProgramOptions{
-	// 		LogLevel: 3,
-	// 		LogSize:  80 * 1024,
-	// 	},
-	// }
+
 	var ve *ebpf.VerifierError
 	objs := bpfObjects{}
 	if err := loadBpfObjects(&objs, nil); err != nil {
@@ -73,20 +67,25 @@ func main() {
 	log.Printf("Press Ctrl-C to exit and remove the program")
 
 	b := bpfBackend{
+		// Hardcoded Src IP (main Nic)
 		Saddr: ip2int("10.8.125.12"),
+		// Hardcoded Dst IP (container)
 		Daddr: ip2int("192.168.10.2"),
+		// Hardcoded Dst Port (UDP echo server)
 		Dport: 9875,
 		// Host-Side Veth Mac
 		Shwaddr: hwaddr2bytes("06:56:87:ec:fd:1f"),
 		// Container-Side Veth Mac
 		Dhwaddr: hwaddr2bytes("86:ad:33:29:ff:5e"),
 		Nocksum: 0,
+		// Hardcoded Host side Veth index
 		Ifindex: 8,
 	}
 
 	key := bpfVipKey{
+		// Hardcoded main NIC IP
 		Vip: ip2int("10.8.125.12"),
-		//Vip:  ip2int("192.168.10.1"),
+		// Hardcoded main NIC port
 		Port: 8888,
 	}