add 43-tcx-ingress-hello and 44-tcx-egress-hello

43-tcx-ingress-hello/Makefile

@@ -0,0 +1 @@
+../common/Makefile

43-tcx-ingress-hello/README.md

@@ -0,0 +1,22 @@
+
+
+
+## Usage
+
+build:
+
+```
+$ make
+```
+
+run:
+
+```
+$ make run
+
+$ printf 'HTTP/1.1 200 OK\nContent-Length: 0\n\n' |nc -l 9090 &
+
+$ curl http://127.0.0.1:9090
+
+$ make cat
+```

43-tcx-ingress-hello/cilium-ebpf/Makefile

@@ -0,0 +1 @@
+../../common/cilium-ebpf.Makefile

43-tcx-ingress-hello/cilium-ebpf/README.md

@@ -0,0 +1,22 @@
+
+
+
+## Usage
+
+build:
+
+```
+$ make
+```
+
+run:
+
+```
+$ make run
+
+$ printf 'HTTP/1.1 200 OK\nContent-Length: 0\n\n' |nc -l 9090 &
+
+$ curl http://127.0.0.1:9090
+
+$ make cat
+```

43-tcx-ingress-hello/cilium-ebpf/main.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	"context"
+	"github.com/cilium/ebpf"
+	"github.com/cilium/ebpf/link"
+	"github.com/cilium/ebpf/rlimit"
+	"log"
+	"net"
+	"os"
+	"os/signal"
+	"syscall"
+)
+
+// $BPF_CLANG and $BPF_CFLAGS are set by the Makefile
+//go:generate go run github.com/cilium/ebpf/cmd/bpf2go -cc $BPF_CLANG -cflags $BPF_CFLAGS bpf ../main.bpf.c -- -I../ -I../output
+
+func main() {
+	if err := rlimit.RemoveMemlock(); err != nil {
+		log.Fatal(err)
+	}
+
+	objs := bpfObjects{}
+	if err := loadBpfObjects(&objs, nil); err != nil {
+		log.Fatal(err)
+	}
+	defer objs.Close()
+
+	tcIface := "lo"
+	if v := os.Getenv("IFACE"); v != "" {
+		tcIface = v
+	}
+	log.Printf("interface name: %s", tcIface)
+	devID, err := net.InterfaceByName(tcIface)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	lk, err := link.AttachTCX(link.TCXOptions{
+		Interface: devID.Index,
+		Program:   objs.HandleIngress,
+		Attach:    ebpf.AttachTCXIngress,
+	})
+	if err != nil {
+		log.Println(err)
+		return
+	}
+	defer lk.Close()
+
+	ctx, stop := signal.NotifyContext(
+		context.Background(), syscall.SIGINT, syscall.SIGTERM,
+	)
+	defer stop()
+
+	log.Println("...")
+	<-ctx.Done()
+	log.Println("bye bye")
+}

43-tcx-ingress-hello/main.bpf.c

@@ -0,0 +1,44 @@
+#include "vmlinux.h"
+
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_endian.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+#define ETH_P_IP 0x0800 /* Internet Protocol packet	*/ // ipv4
+#define ETH_HLEN 14 /* Total octets in header.	 */
+
+#define TCX_NEXT	 -1
+#define TCX_PASS	  0
+#define TCX_DROP	  2
+#define TCX_REDIRECT  7
+
+SEC("tcx/ingress")
+int handle_ingress(struct __sk_buff *skb) {
+    bpf_skb_pull_data(skb, 0);
+
+    u16 h_proto;
+    if (bpf_skb_load_bytes(skb, offsetof(struct ethhdr, h_proto), &h_proto,
+                           sizeof(h_proto)) < 0)
+        goto out;
+    if (bpf_ntohs(h_proto) != ETH_P_IP) // not ipv4
+        goto out;
+
+    struct iphdr ip_hdr;
+    if (bpf_skb_load_bytes(skb, ETH_HLEN, &ip_hdr, sizeof(ip_hdr)) < 0)
+        return 0;
+    if (ip_hdr.protocol != IPPROTO_TCP) // not tcp
+        return 0;
+
+    struct tcphdr tcp_hdr;
+    if (bpf_skb_load_bytes(skb, ETH_HLEN + sizeof(struct iphdr), &tcp_hdr,
+                           sizeof(tcp_hdr)) < 0)
+        goto out;
+
+    bpf_printk("saddr: %pI4:%d, daddr: %pI4:%d", &ip_hdr.saddr, bpf_htons(tcp_hdr.source), &ip_hdr.daddr, bpf_htons(tcp_hdr.dest));
+
+out:
+    return TCX_NEXT;
+}
+
+char _license[] SEC("license") = "GPL";

43-tcx-ingress-hello/main.go

@@ -0,0 +1,9 @@
+package main
+
+import (
+	"log"
+)
+
+func main() {
+	log.Fatal("libbpfgo doesn't support TCX yet. go to ./cilium-ebpf/ to run example")
+}