Wrap printk with MACRO and disable them

Wrap printk traces with a MACRO PRINTK to disable/enable in one shot, and disable them by default.
datahangar · Aug 24, 2024 · 447ac27 · 447ac27
1 parent f3d957a
commit 447ac27
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Showing 3 changed files with 18 additions and 11 deletions.
diff --git a/src/common.h b/src/common.h
@@ -1,11 +1,17 @@
 #ifndef FUNNEL_COMMON_H
 #define FUNNEL_COMMON_H
 
+#if 0
+	#define PRINTK(...) bpf_printk( __VA_ARGS__ )
+#else
+	#define PRINTK(...) 
+#endif
+
 #define SKB_GET_ETH( SKB ) (struct ethhdr*)(unsigned long long)skb->data
 
 #define CHECK_SKB_PTR( SKB, PTR ) \
 	if (  (void*)(PTR) > ((void*)(unsigned long long) SKB -> data_end )) {	\
-		bpf_printk("PTR: %p on pkt with length: %d out of bounds!\n",   \
+		PRINTK("PTR: %p on pkt with length: %d out of bounds!\n",   \
 								PTR, SKB ->len);\
 		return TC_ACT_OK;						\
 	} do{}while(0)

diff --git a/src/funnel.c b/src/funnel.c
@@ -22,9 +22,10 @@ static __always_inline int ip4_funnel_udp_thru_tcp(struct __sk_buff* skb,
 
 	//Store current UDP offset & content of udp header
 	__u32 l3_off = (__u8*)ip - (__u8*)SKB_GET_ETH(skb);
-	__u32 l4_off = (__u8*)udp - (__u8*)SKB_GET_ETH(skb);
+	__u32  l4_off __attribute__((unused)) =
+					(__u8*)udp - (__u8*)SKB_GET_ETH(skb);
 
-	bpf_printk("UDP packet of length: %u, offset: %u!\n", skb->len, l4_off);
+	PRINTK("UDP packet of length: %u, offset: %u!\n", skb->len, l4_off);
 
 	//Change IP PROTO
 	union ttl_proto old_ttl = *(union ttl_proto*)&ip->ttl;
@@ -42,13 +43,13 @@ static __always_inline int ip4_funnel_udp_thru_tcp(struct __sk_buff* skb,
 							0,
 							diff, 0);
 	if(rc < 0){
-		bpf_printk("ERROR l3_csum_replace: %d", rc);
+		PRINTK("ERROR l3_csum_replace: %d", rc);
 		return TC_ACT_SHOT;
 	}
 	rc = bpf_skb_adjust_room(skb, sizeof(struct tcphdr), BPF_ADJ_ROOM_NET,
 							0);
 	if(rc < 0){
-		bpf_printk("ERROR adjust room: %d", rc);
+		PRINTK("ERROR adjust room: %d", rc);
 		return TC_ACT_SHOT;
 	}
 
@@ -135,7 +136,7 @@ int tc_ingress(struct __sk_buff *skb){
 		return proc_ip4(skb, ip);
 	}else if(eth->h_proto == bpf_htons(ETH_P_IPV6)){
 		//XXX
-		bpf_printk("IPv6 packet with length: %d NOT SUPPORTED!\n", skb->len);
+		PRINTK("IPv6 packet with length: %d NOT SUPPORTED!\n", skb->len);
 	}
 
 	return TC_ACT_UNSPEC;

diff --git a/src/unfunnel.c b/src/unfunnel.c
@@ -21,7 +21,7 @@ static __always_inline int ip4_unfunnel_udp_thru_tcp(struct __sk_buff* skb,
 	__s64 diff = bpf_csum_diff((__be32*)&old_ttl, 4, (__be32*)&ip->ttl, 4,
 								0);
 	if(diff < 0){
-		bpf_printk("ERROR csum_diff: %d", diff);
+		PRINTK("ERROR csum_diff: %d", diff);
 		return TC_ACT_SHOT;
 	}
 
@@ -30,7 +30,7 @@ static __always_inline int ip4_unfunnel_udp_thru_tcp(struct __sk_buff* skb,
 	ip->tot_len = bpf_htons(bpf_ntohs(ip->tot_len)-sizeof(struct tcphdr));
 	diff = bpf_csum_diff((__be32*)&old_totlen, 4, (__be32*)ip, 4, diff);
 	if(diff < 0){
-		bpf_printk("ERROR csum_diff: %d", diff);
+		PRINTK("ERROR csum_diff: %d", diff);
 		return TC_ACT_SHOT;
 	}
 
@@ -40,12 +40,12 @@ static __always_inline int ip4_unfunnel_udp_thru_tcp(struct __sk_buff* skb,
 							0,
 							diff, 0);
 	if(rc < 0){
-		bpf_printk("ERROR l3_csum_replace: %d", rc);
+		PRINTK("ERROR l3_csum_replace: %d", rc);
 		return TC_ACT_SHOT;
 	}
 	rc = bpf_skb_adjust_room(skb, -(__s32)sizeof(struct tcphdr), BPF_ADJ_ROOM_NET, 0);
 	if(rc < 0){
-		bpf_printk("ERROR adjust room: %d", rc);
+		PRINTK("ERROR adjust room: %d", rc);
 		return TC_ACT_SHOT;
 	}
 
@@ -82,7 +82,7 @@ int tc_ingress(struct __sk_buff *skb){
 		return proc_ip4(skb, ip);
 	}else if(eth->h_proto == bpf_htons(ETH_P_IPV6)){
 		//XXX
-		bpf_printk("IPv6 packet with length: %d NOT SUPPORTED!\n", skb->len);
+		PRINTK("IPv6 packet with length: %d NOT SUPPORTED!\n", skb->len);
 	}
 
 	return TC_ACT_UNSPEC;