sock: Fix capturing extra packets from other dev

Create PF_PACKET socket with proto=0 which does not setup packet handler
and will not capture packets until bind() will be invoked.

Also replaced pf_tx_socket by pf_socket as these funcs became the same,
as proto arg is set to 0.

Suggested-by: Daniel Borkmann <borkmann@iogearbox.net>
Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

sock.c

@@ -25,19 +25,10 @@ int af_socket(int af)
 }
 
 int pf_socket(void)
-{
-	int sock = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
-	if (unlikely(sock < 0))
-		panic("Creation of PF socket failed: %s\n", strerror(errno));
-
-	return sock;
-}
-
-int pf_tx_socket(void)
 {
 	int sock = socket(PF_PACKET, SOCK_RAW, 0);
 	if (unlikely(sock < 0))
-		panic("Creation of PF TX socket failed: %s\n", strerror(errno));
+		panic("Creation of PF socket failed: %s\n", strerror(errno));
 
 	return sock;
 }

sock.h

@@ -3,7 +3,6 @@
 
 extern int af_socket(int af);
 extern int pf_socket(void);
-extern int pf_tx_socket(void);
 extern void set_nonblocking(int fd);
 extern int set_nonblocking_sloppy(int fd);
 extern int set_reuseaddr(int fd);

trafgen.c

@@ -822,7 +822,7 @@ static void main_loop(struct ctx *ctx, char *confname, bool slow,
 		fflush(stdout);
 	}
 
-	sock = pf_tx_socket();
+	sock = pf_socket();
 
 	if (ctx->qdisc_path == false)
 		set_sock_qdisc_bypass(sock, ctx->verbose);