move bpf c code to local for nodetrace

Signed-off-by: Menglong Dong <imagedong@tencent.com>

Author: menglongdong

nodetrace/.gitignore

@@ -1,3 +1,2 @@
 watch
 mark
-progs/ntrace.c

nodetrace/Makefile

@@ -7,9 +7,6 @@ prog-watch = watch.c $(COMMON_SHARED)
 
 include ../common.mk
 
-$(foreach i,$(bpf_progs),$(i).c):
-	$(call cmd_download,$@,nodetrace/$@)
-
 all: $(progs)
 
 install: all

nodetrace/progs/ntrace.c

@@ -0,0 +1,113 @@
+#include <vmlinux.h>
+#include <bpf_helpers.h>
+#include <bpf_endian.h>
+
+#include <macro.h>
+#include "shared.h"
+#include <skb_utils.h>
+
+#define MARK_TOS_VALUE	0xe0
+
+bpf_args_t _bpf_args = {
+	.quiet = true
+};
+
+static inline void do_mark(struct __sk_buff *skb, struct iphdr *ip)
+{
+	__u8 old_tos = ip->tos;
+	ip->tos = MARK_TOS_VALUE;
+	bpf_l3_csum_replace(skb, IP_CSUM_OFFSET, bpf_htons(old_tos),
+			    bpf_htons(MARK_TOS_VALUE),
+			    2);
+}
+
+static inline bool is_marked(struct iphdr *ip)
+{
+	return (ip->tos & MARK_TOS_VALUE) == MARK_TOS_VALUE;
+}
+
+
+/* mark the packet which to be traced. For now, the method of
+ * marking is to set TOS in ip header to a special value.
+ *
+ * This eBPF with the type of TC is about to attach to the egress
+ * of TC filter.
+ */
+SEC("tc")
+int ntrace_mark(struct __sk_buff *skb)
+{
+	event_t event = {.location = LOCALTION_MARK};
+	struct ethhdr *eth = SKB_DATA(skb);
+	struct iphdr *ip;
+
+	eth = SKB_DATA(skb);
+	if (SKB_CHECK_IP(skb))
+		goto out;
+
+	if (eth->h_proto != bpf_htons(ETH_P_IP))
+		goto out;
+
+	ip = SKB_HDR_IP(skb);
+	if (ip->tos & MARK_TOS_VALUE) {
+		bpf_printk("ctrace: conflict mark(tos) value found: %x\n",
+			   ip->tos);
+		goto out;
+	}
+
+	if (direct_parse_skb(skb, &event.pkt, &_bpf_args.pkt))
+		goto out;
+
+	do_mark(skb, ip);
+	if (!_bpf_args.quiet)
+		EVENT_OUTPUT(skb, event);
+
+	return TC_ACT_OK;
+out:
+	return TC_ACT_UNSPEC;
+}
+
+
+/*******************************************************************
+ * 
+ * Following functions aim to trace the receive and send of marked
+ * packet.
+ * 
+ * ctrace_entry() is used to trace the packet entry to the node, and
+ * ctrace_exit() is used to trace the packet leave.
+ * 
+ *******************************************************************/
+
+static inline void try_output_skb(struct __sk_buff *skb, __u8 location)
+{
+	event_t event = { .location = location };
+	struct ethhdr *eth = SKB_DATA(skb);
+	struct iphdr *ip;
+
+	if (SKB_CHECK_IP(skb))
+		return;
+
+	if (eth->h_proto != bpf_htons(ETH_P_IP))
+		return;
+
+	ip = SKB_HDR_IP(skb);
+	if (!is_marked(ip) || direct_parse_skb(skb, &event.pkt, NULL))
+		return;
+
+	EVENT_OUTPUT(skb, event);
+}
+
+SEC("tc")
+int ntrace_entry(struct __sk_buff *skb)
+{
+	try_output_skb(skb, LOCALTION_INGRESS);
+	return TC_ACT_UNSPEC;
+}
+
+SEC("tc")
+int ntrace_exit(struct __sk_buff *skb)
+{
+	try_output_skb(skb, LOCALTION_EGRESS);
+	return TC_ACT_UNSPEC;
+}
+
+char _license[] SEC("license") = "GPL";