[PATCH net-next v2 1/6] netconsole: add an address family to struct inet_addr

[Gustavo Luiz Duarte]

netconsole_target stores a single 'bool ipv6' to denote the target's
address family. This makes it hard to detect conditions like "no address
set" or ipv4/ipv6 mixup between local_ip and remote_ip.

Add a 'family' field to inet_addr so each address stores its own address
family: AF_UNSPEC while unset, else AF_INET or AF_INET6.

Nothing reads the new field yet. The next patch switches the users over
and removes the bool. No functional change.

Signed-off-by: Gustavo Luiz Duarte <gustavold@xxxxxxxxx>
---
 drivers/net/netconsole.c | 24 +++++++++++++++---------
 include/linux/netpoll.h  | 10 +++++++---
 2 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 03913302328c..94a662c7369a 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -212,7 +212,7 @@ struct netconsole_target {
 	bool			extended;
 	bool			release;
 	struct netpoll		np;
-	union inet_addr		local_ip, remote_ip;
+	struct inet_addr	local_ip, remote_ip;
 	bool			ipv6;
 	u16			local_port, remote_port;
 	u8			remote_mac[ETH_ALEN];
@@ -415,6 +415,7 @@ static int netcons_take_ipv6(struct netconsole_target *nt,
 				continue;
 			/* Got the IP, let's return */
 			nt->local_ip.in6 = ifp->addr;
+			nt->local_ip.family = AF_INET6;
 			err = 0;
 			break;
 		}
@@ -456,6 +457,7 @@ static int netcons_take_ipv4(struct netconsole_target *nt,
 	}
 
 	nt->local_ip.ip = ifa->ifa_local;
+	nt->local_ip.family = AF_INET;
 	np_info(np, "local IP %pI4\n", &nt->local_ip.ip);
 
 	return 0;
@@ -728,10 +730,10 @@ static void netconsole_print_banner(struct netconsole_target *nt)
 	np_info(np, "remote ethernet address %pM\n", nt->remote_mac);
 }
 
-/* Parse the string and populate the `inet_addr` union. Return 0 if IPv4 is
+/* Parse the string and populate the `inet_addr` struct. Return 0 if IPv4 is
  * populated, 1 if IPv6 is populated, and -1 upon failure.
  */
-static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
+static int netpoll_parse_ip_addr(const char *str, struct inet_addr *addr)
 {
 	const char *end = NULL;
 	int len;
@@ -743,14 +745,18 @@ static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
 	if (str[len - 1] == '\n')
 		len -= 1;
 
-	if (in4_pton(str, len, (void *)addr, -1, &end) > 0 &&
-	    (!end || *end == 0 || *end == '\n'))
+	if (in4_pton(str, len, (void *)&addr->ip, -1, &end) > 0 &&
+	    (!end || *end == 0 || *end == '\n')) {
+		addr->family = AF_INET;
 		return 0;
+	}
 
 	if (IS_ENABLED(CONFIG_IPV6) &&
-	    in6_pton(str, len, (void *)addr, -1, &end) > 0 &&
-	    (!end || *end == 0 || *end == '\n'))
+	    in6_pton(str, len, (void *)&addr->in6, -1, &end) > 0 &&
+	    (!end || *end == 0 || *end == '\n')) {
+		addr->family = AF_INET6;
 		return 1;
+	}
 
 	return -1;
 }
@@ -858,7 +864,7 @@ static ssize_t local_ip_show(struct config_item *item, char *buf)
 	if (nt->ipv6)
 		return sysfs_emit(buf, "%pI6c\n", &nt->local_ip.in6);
 	else
-		return sysfs_emit(buf, "%pI4\n", &nt->local_ip);
+		return sysfs_emit(buf, "%pI4\n", &nt->local_ip.ip);
 }
 
 static ssize_t remote_ip_show(struct config_item *item, char *buf)
@@ -868,7 +874,7 @@ static ssize_t remote_ip_show(struct config_item *item, char *buf)
 	if (nt->ipv6)
 		return sysfs_emit(buf, "%pI6c\n", &nt->remote_ip.in6);
 	else
-		return sysfs_emit(buf, "%pI4\n", &nt->remote_ip);
+		return sysfs_emit(buf, "%pI4\n", &nt->remote_ip.ip);
 }
 
 static ssize_t local_mac_show(struct config_item *item, char *buf)
diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h
index 1c6b1eec5efd..de97f001a0f9 100644
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h
@@ -16,9 +16,13 @@
 #include <linux/ip.h>
 #include <linux/udp.h>
 
-union inet_addr {
-	__be32		ip;
-	struct in6_addr	in6;
+struct inet_addr {
+	/* Address family: AF_UNSPEC when unset, else AF_INET or AF_INET6 */
+	u8			family;
+	union {
+		__be32		ip;
+		struct in6_addr	in6;
+	};
 };
 
 struct netpoll {

-- 
2.55.0