mptcp: add mptcp_pm_genl_fill_addr helper

To save some redundant code in dump_addr() interfaces of both the
netlink PM and userspace PM, the code that calls netlink message
helpers (genlmsg_put/cancel/end) and mptcp_nl_fill_addr() is wrapped
into a new helper mptcp_pm_genl_fill_addr().

This helper will also be used in BPF path managers.

Signed-off-by: Geliang Tang <[email protected]>

Author: Geliang Tang

net/mptcp/pm.c

@@ -489,6 +489,27 @@ int mptcp_pm_nl_get_addr_doit(struct sk_buff *skb, struct genl_info *info)
 	return ret;
 }
 
+int mptcp_pm_genl_fill_addr(struct sk_buff *msg,
+			    struct netlink_callback *cb,
+			    struct mptcp_pm_addr_entry *entry)
+{
+	void *hdr;
+
+	hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).portid,
+			  cb->nlh->nlmsg_seq, &mptcp_genl_family,
+			  NLM_F_MULTI, MPTCP_PM_CMD_GET_ADDR);
+	if (!hdr)
+		return -EINVAL;
+
+	if (mptcp_nl_fill_addr(msg, entry) < 0) {
+		genlmsg_cancel(msg, hdr);
+		return -EINVAL;
+	}
+
+	genlmsg_end(msg, hdr);
+	return 0;
+}
+
 static int mptcp_pm_dump_addr(struct sk_buff *msg, struct netlink_callback *cb)
 {
 	const struct genl_info *info = genl_info_dump(cb);

net/mptcp/pm_netlink.c

@@ -1798,7 +1798,6 @@ int mptcp_pm_nl_dump_addr(struct sk_buff *msg,
 	struct mptcp_pm_addr_entry *entry;
 	struct pm_nl_pernet *pernet;
 	int id = cb->args[0];
-	void *hdr;
 	int i;
 
 	pernet = pm_nl_get_pernet(net);
@@ -1813,19 +1812,10 @@ int mptcp_pm_nl_dump_addr(struct sk_buff *msg,
 			if (entry->addr.id <= id)
 				continue;
 
-			hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).portid,
-					  cb->nlh->nlmsg_seq, &mptcp_genl_family,
-					  NLM_F_MULTI, MPTCP_PM_CMD_GET_ADDR);
-			if (!hdr)
+			if (mptcp_pm_genl_fill_addr(msg, cb, entry))
 				break;
 
-			if (mptcp_nl_fill_addr(msg, entry) < 0) {
-				genlmsg_cancel(msg, hdr);
-				break;
-			}
-
 			id = entry->addr.id;
-			genlmsg_end(msg, hdr);
 		}
 	}
 	rcu_read_unlock();

net/mptcp/pm_userspace.c

@@ -641,7 +641,6 @@ int mptcp_userspace_pm_dump_addr(struct sk_buff *msg,
 	struct mptcp_sock *msk;
 	int ret = -EINVAL;
 	struct sock *sk;
-	void *hdr;
 
 	bitmap = (struct id_bitmap *)cb->ctx;
 
@@ -657,19 +656,10 @@ int mptcp_userspace_pm_dump_addr(struct sk_buff *msg,
 		if (test_bit(entry->addr.id, bitmap->map))
 			continue;
 
-		hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).portid,
-				  cb->nlh->nlmsg_seq, &mptcp_genl_family,
-				  NLM_F_MULTI, MPTCP_PM_CMD_GET_ADDR);
-		if (!hdr)
+		if (mptcp_pm_genl_fill_addr(msg, cb, entry))
 			break;
 
-		if (mptcp_nl_fill_addr(msg, entry) < 0) {
-			genlmsg_cancel(msg, hdr);
-			break;
-		}
-
 		__set_bit(entry->addr.id, bitmap->map);
-		genlmsg_end(msg, hdr);
 	}
 	spin_unlock_bh(&msk->pm.lock);
 	release_sock(sk);

net/mptcp/protocol.h

@@ -1131,6 +1131,9 @@ int mptcp_pm_nl_dump_addr(struct sk_buff *msg,
 			  struct netlink_callback *cb);
 int mptcp_userspace_pm_dump_addr(struct sk_buff *msg,
 				 struct netlink_callback *cb);
+int mptcp_pm_genl_fill_addr(struct sk_buff *msg,
+			    struct netlink_callback *cb,
+			    struct mptcp_pm_addr_entry *entry);
 int mptcp_pm_nl_get_addr(u8 id, struct mptcp_pm_addr_entry *addr,
 			 struct genl_info *info);
 int mptcp_userspace_pm_get_addr(u8 id, struct mptcp_pm_addr_entry *addr,