[GENL]: Add genlmsg_put_reply() to simplify building reply headers

By modyfing genlmsg_put() to take a genl_family and by adding
genlmsg_put_reply() the process of constructing the netlink
and generic netlink headers is simplified.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/genetlink.h

@@ -79,33 +79,50 @@ extern struct sock *genl_sock;
  * @skb: socket buffer holding the message
  * @pid: netlink pid the message is addressed to
  * @seq: sequence number (usually the one of the sender)
- * @type: netlink message type
- * @hdrlen: length of the user specific header
+ * @family: generic netlink family
  * @flags netlink message flags
  * @cmd: generic netlink command
- * @version: version
  *
  * Returns pointer to user specific header
  */
 static inline void *genlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,
-				int type, int hdrlen, int flags,
-				u8 cmd, u8 version)
+				struct genl_family *family, int flags, u8 cmd)
 {
 	struct nlmsghdr *nlh;
 	struct genlmsghdr *hdr;
 
-	nlh = nlmsg_put(skb, pid, seq, type, GENL_HDRLEN + hdrlen, flags);
+	nlh = nlmsg_put(skb, pid, seq, family->id, GENL_HDRLEN +
+			family->hdrsize, flags);
 	if (nlh == NULL)
 		return NULL;
 
 	hdr = nlmsg_data(nlh);
 	hdr->cmd = cmd;
-	hdr->version = version;
+	hdr->version = family->version;
 	hdr->reserved = 0;
 
 	return (char *) hdr + GENL_HDRLEN;
 }
 
+/**
+ * genlmsg_put_reply - Add generic netlink header to a reply message
+ * @skb: socket buffer holding the message
+ * @info: receiver info
+ * @family: generic netlink family
+ * @flags: netlink message flags
+ * @cmd: generic netlink command
+ *
+ * Returns pointer to user specific header
+ */
+static inline void *genlmsg_put_reply(struct sk_buff *skb,
+				      struct genl_info *info,
+				      struct genl_family *family,
+				      int flags, u8 cmd)
+{
+	return genlmsg_put(skb, info->snd_pid, info->snd_seq, family,
+			   flags, cmd);
+}
+
 /**
  * genlmsg_end - Finalize a generic netlink message
  * @skb: socket buffer the message is stored in

kernel/taskstats.c

@@ -85,13 +85,9 @@ static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
 		int seq = get_cpu_var(taskstats_seqnum)++;
 		put_cpu_var(taskstats_seqnum);
 
-		reply = genlmsg_put(skb, 0, seq,
-				family.id, 0, 0,
-				cmd, family.version);
+		reply = genlmsg_put(skb, 0, seq, &family, 0, cmd);
 	} else
-		reply = genlmsg_put(skb, info->snd_pid, info->snd_seq,
-				family.id, 0, 0,
-				cmd, family.version);
+		reply = genlmsg_put_reply(skb, info, &family, 0, cmd);
 	if (reply == NULL) {
 		nlmsg_free(skb);
 		return -EINVAL;

net/netlabel/netlabel_cipso_v4.c

@@ -457,12 +457,8 @@ static int netlbl_cipsov4_list(struct sk_buff *skb, struct genl_info *info)
 		ret_val = -ENOMEM;
 		goto list_failure;
 	}
-	data = netlbl_netlink_hdr_put(ans_skb,
-				      info->snd_pid,
-				      info->snd_seq,
-				      netlbl_cipsov4_gnl_family.id,
-				      0,
-				      NLBL_CIPSOV4_C_LIST);
+	data = genlmsg_put_reply(ans_skb, info, &netlbl_cipsov4_gnl_family,
+				 0, NLBL_CIPSOV4_C_LIST);
 	if (data == NULL) {
 		ret_val = -ENOMEM;
 		goto list_failure;
@@ -607,12 +603,9 @@ static int netlbl_cipsov4_listall_cb(struct cipso_v4_doi *doi_def, void *arg)
 	struct netlbl_cipsov4_doiwalk_arg *cb_arg = arg;
 	void *data;
 
-	data = netlbl_netlink_hdr_put(cb_arg->skb,
-				      NETLINK_CB(cb_arg->nl_cb->skb).pid,
-				      cb_arg->seq,
-				      netlbl_cipsov4_gnl_family.id,
-				      NLM_F_MULTI,
-				      NLBL_CIPSOV4_C_LISTALL);
+	data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).pid,
+			   cb_arg->seq, &netlbl_cipsov4_gnl_family,
+			   NLM_F_MULTI, NLBL_CIPSOV4_C_LISTALL);
 	if (data == NULL)
 		goto listall_cb_failure;
 

net/netlabel/netlabel_mgmt.c

@@ -188,12 +188,9 @@ static int netlbl_mgmt_listall_cb(struct netlbl_dom_map *entry, void *arg)
 	struct netlbl_domhsh_walk_arg *cb_arg = arg;
 	void *data;
 
-	data = netlbl_netlink_hdr_put(cb_arg->skb,
-				      NETLINK_CB(cb_arg->nl_cb->skb).pid,
-				      cb_arg->seq,
-				      netlbl_mgmt_gnl_family.id,
-				      NLM_F_MULTI,
-				      NLBL_MGMT_C_LISTALL);
+	data = genlmsg_put(cb_arg->skb, NETLINK_CB(cb_arg->nl_cb->skb).pid,
+			   cb_arg->seq, &netlbl_mgmt_gnl_family,
+			   NLM_F_MULTI, NLBL_MGMT_C_LISTALL);
 	if (data == NULL)
 		goto listall_cb_failure;
 
@@ -359,12 +356,8 @@ static int netlbl_mgmt_listdef(struct sk_buff *skb, struct genl_info *info)
 	ans_skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 	if (ans_skb == NULL)
 		return -ENOMEM;
-	data = netlbl_netlink_hdr_put(ans_skb,
-				      info->snd_pid,
-				      info->snd_seq,
-				      netlbl_mgmt_gnl_family.id,
-				      0,
-				      NLBL_MGMT_C_LISTDEF);
+	data = genlmsg_put_reply(ans_skb, info, &netlbl_mgmt_gnl_family,
+				 0, NLBL_MGMT_C_LISTDEF);
 	if (data == NULL)
 		goto listdef_failure;
 
@@ -422,11 +415,8 @@ static int netlbl_mgmt_protocols_cb(struct sk_buff *skb,
 	int ret_val = -ENOMEM;
 	void *data;
 
-	data = netlbl_netlink_hdr_put(skb,
-				      NETLINK_CB(cb->skb).pid,
-				      cb->nlh->nlmsg_seq,
-				      netlbl_mgmt_gnl_family.id,
-				      NLM_F_MULTI,
+	data = genlmsg_put(skb, NETLINK_CB(cb->skb).pid, cb->nlh->nlmsg_seq,
+			   &netlbl_mgmt_gnl_family, NLM_F_MULTI,
 			   NLBL_MGMT_C_PROTOCOLS);
 	if (data == NULL)
 		goto protocols_cb_failure;
@@ -495,12 +485,8 @@ static int netlbl_mgmt_version(struct sk_buff *skb, struct genl_info *info)
 	ans_skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 	if (ans_skb == NULL)
 		return -ENOMEM;
-	data = netlbl_netlink_hdr_put(ans_skb,
-				      info->snd_pid,
-				      info->snd_seq,
-				      netlbl_mgmt_gnl_family.id,
-				      0,
-				      NLBL_MGMT_C_VERSION);
+	data = genlmsg_put_reply(ans_skb, info, &netlbl_mgmt_gnl_family,
+				 0, NLBL_MGMT_C_VERSION);
 	if (data == NULL)
 		goto version_failure;
 

net/netlabel/netlabel_unlabeled.c

@@ -141,12 +141,8 @@ static int netlbl_unlabel_list(struct sk_buff *skb, struct genl_info *info)
 	ans_skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 	if (ans_skb == NULL)
 		goto list_failure;
-	data = netlbl_netlink_hdr_put(ans_skb,
-				      info->snd_pid,
-				      info->snd_seq,
-				      netlbl_unlabel_gnl_family.id,
-				      0,
-				      NLBL_UNLABEL_C_LIST);
+	data = genlmsg_put_reply(ans_skb, info, &netlbl_unlabel_gnl_family,
+				 0, NLBL_UNLABEL_C_LIST);
 	if (data == NULL) {
 		ret_val = -ENOMEM;
 		goto list_failure;

net/netlabel/netlabel_user.h

@@ -41,37 +41,6 @@
 
 /* NetLabel NETLINK helper functions */
 
-/**
- * netlbl_netlink_hdr_put - Write the NETLINK buffers into a sk_buff
- * @skb: the packet
- * @pid: the PID of the receipient
- * @seq: the sequence number
- * @type: the generic NETLINK message family type
- * @cmd: command
- *
- * Description:
- * Write both a NETLINK nlmsghdr structure and a Generic NETLINK genlmsghdr
- * struct to the packet.  Returns a pointer to the start of the payload buffer
- * on success or NULL on failure.
- *
- */
-static inline void *netlbl_netlink_hdr_put(struct sk_buff *skb,
-					   u32 pid,
-					   u32 seq,
-					   int type,
-					   int flags,
-					   u8 cmd)
-{
-	return genlmsg_put(skb,
-			   pid,
-			   seq,
-			   type,
-			   0,
-			   flags,
-			   cmd,
-			   NETLBL_PROTO_VERSION);
-}
-
 /**
  * netlbl_netlink_auditinfo - Fetch the audit information from a NETLINK msg
  * @skb: the packet

net/netlink/genetlink.c

@@ -384,6 +384,13 @@ static void genl_rcv(struct sock *sk, int len)
  * Controller
  **************************************************************************/
 
+static struct genl_family genl_ctrl = {
+	.id = GENL_ID_CTRL,
+	.name = "nlctrl",
+	.version = 0x1,
+	.maxattr = CTRL_ATTR_MAX,
+};
+
 static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
 			  u32 flags, struct sk_buff *skb, u8 cmd)
 {
@@ -392,8 +399,7 @@ static int ctrl_fill_info(struct genl_family *family, u32 pid, u32 seq,
 	void *hdr;
 	int idx = 1;
 
-	hdr = genlmsg_put(skb, pid, seq, GENL_ID_CTRL, 0, flags, cmd,
-			  family->version);
+	hdr = genlmsg_put(skb, pid, seq, &genl_ctrl, flags, cmd);
 	if (hdr == NULL)
 		return -1;
 
@@ -562,13 +568,6 @@ static struct genl_ops genl_ctrl_ops = {
 	.policy		= ctrl_policy,
 };
 
-static struct genl_family genl_ctrl = {
-	.id = GENL_ID_CTRL,
-	.name = "nlctrl",
-	.version = 0x1,
-	.maxattr = CTRL_ATTR_MAX,
-};
-
 static int __init genl_init(void)
 {
 	int i, err;