packet: Support fanout

This one may be present and may be not, thus it's optional in the image.
The C-binding we use report the field absense in the parsed stream via
the has_xxx field, but in the google docs it's stated, that

	"When a message is parsed, if it does not contain an optional
	 element, the corresponding field in the parsed object is set
	 to the default value for that field."

Thus, I also declare the default value for it to be not zero as 0 is
a valid fanout configuration.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

include/sk-packet.h

@@ -18,4 +18,8 @@ extern int packet_receive_one(struct nlmsghdr *h, void *arg);
 #ifndef PACKET_VNET_HDR
 #define PACKET_VNET_HDR 15
 #endif
+
+#ifndef PACKET_FANOUT
+#define PACKET_FANOUT	18
+#endif
 #endif

protobuf/packet-sock.proto

@@ -26,4 +26,5 @@ message packet_sock_entry {
 	required uint32		timestamp	= 14;
 	required uint32		copy_thresh	= 15;
 	repeated packet_mclist	mclist		= 16;
+	optional uint32		fanout		= 17 [ default = 0xffffffff ];
 }

sk-packet.c

@@ -35,8 +35,11 @@ struct packet_sock_desc {
 	struct packet_diag_info nli;
 	int mreq_n;
 	struct packet_diag_mclist *mreqs;
+	unsigned int fanout;
 };
 
+#define NO_FANOUT	((unsigned int)-1)
+
 void show_packetsk(int fd, struct cr_options *o)
 {
 	pb_show_plain(fd, PB_PACKETSK);
@@ -140,6 +143,11 @@ static int dump_one_packet_fd(int lfd, u32 id, const struct fd_parms *p)
 	if (ret)
 		goto out;
 
+	if (sd->fanout != NO_FANOUT) {
+		psk.has_fanout = true;
+		psk.fanout = sd->fanout;
+	}
+
 	ret = pb_write_one(fdset_fd(glob_fdset, CR_FD_PACKETSK), &psk, PB_PACKETSK);
 out:
 	for (i = 0; i < psk.n_mclist; i++)
@@ -202,6 +210,11 @@ int packet_receive_one(struct nlmsghdr *hdr, void *arg)
 	if (packet_save_mreqs(sd, tb[PACKET_DIAG_MCLIST]))
 		return -1;
 
+	if (tb[PACKET_DIAG_FANOUT])
+		sd->fanout = *(__u32 *)RTA_DATA(tb[PACKET_DIAG_FANOUT]);
+	else
+		sd->fanout = NO_FANOUT;
+
 	return sk_collect_one(m->pdiag_ino, PF_PACKET, &sd->sd);
 }
 
@@ -299,6 +312,12 @@ static int open_packet_sk(struct file_desc *d)
 	if (restore_mreqs(sk, pse))
 		goto err_cl;
 
+	if (pse->has_fanout) {
+		pr_info("Restoring fanout %x\n", pse->fanout);
+		if (restore_opt(sk, SOL_PACKET, PACKET_FANOUT, &pse->fanout))
+			goto err_cl;
+	}
+
 	if (rst_file_params(sk, pse->fown, pse->flags))
 		goto err_cl;
 

sockets.c

@@ -273,7 +273,8 @@ int collect_sockets(int pid)
 
 	req.r.p.sdiag_family	= AF_PACKET;
 	req.r.p.sdiag_protocol	= 0;
-	req.r.p.pdiag_show	= PACKET_SHOW_INFO | PACKET_SHOW_MCLIST;
+	req.r.p.pdiag_show	= PACKET_SHOW_INFO | PACKET_SHOW_MCLIST |
+					PACKET_SHOW_FANOUT;
 	tmp = do_rtnl_req(nl, &req, sizeof(req), packet_receive_one, NULL);
 	if (tmp)
 		err = tmp;