[PATCH net-next 2/4] netconsole: use the address family instead of the ipv6 flag

[Gustavo Luiz Duarte <gustavold@gmail.com>]

Now that we have the address family in inet_addr, use that and remove
nt->ipv6.

We no longer need netcons_local_ip_unset() to check that all bytes are
zeroes, as that is now denoted by (family == AF_UNSPEC).

Signed-off-by: Gustavo Luiz Duarte <gustavold@gmail.com>
---
 drivers/net/netconsole.c | 82 ++++++++++++++----------------------------------
 1 file changed, 23 insertions(+), 59 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index d615a9256787..070bae7b4fd7 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -181,7 +181,6 @@ enum target_state {
  *		local_mac	(read-only)
  * @local_ip:	Source IP address of the target (read-write).
  * @remote_ip:	Destination IP address of the target (read-write).
- * @ipv6:	Whether the target addresses are IPv6 (read-write).
  * @local_port:	Source UDP port of the target (read-write).
  * @remote_port: Destination UDP port of the target (read-write).
  * @remote_mac:	Destination ethernet address of the target (read-write).
@@ -213,7 +212,6 @@ struct netconsole_target {
 	bool			release;
 	struct netpoll		np;
 	struct inet_addr	local_ip, remote_ip;
-	bool			ipv6;
 	u16			local_port, remote_port;
 	u8			remote_mac[ETH_ALEN];
 	/* protected by target_list_lock; +1 gives scnprintf() room for its
@@ -463,23 +461,6 @@ static int netcons_take_ipv4(struct netconsole_target *nt,
 	return 0;
 }
 
-/*
- * Test whether the caller left nt->local_ip unset, so that
- * netcons_netpoll_setup() should auto-populate it from the egress device.
- *
- * nt->local_ip is a union of __be32 (IPv4) and struct in6_addr (IPv6),
- * so an IPv6 address whose first 4 bytes are zero (e.g. ::1, ::2,
- * IPv4-mapped ::ffff:a.b.c.d) must not be tested via the IPv4 arm —
- * doing so would misclassify a caller-supplied address as unset and
- * silently overwrite it with whatever address the device exposes.
- */
-static bool netcons_local_ip_unset(const struct netconsole_target *nt)
-{
-	if (nt->ipv6)
-		return ipv6_addr_any(&nt->local_ip.in6);
-	return !nt->local_ip.ip;
-}
-
 static int netcons_netpoll_setup(struct netconsole_target *nt)
 {
 	struct net *net = current->nsproxy->net_ns;
@@ -525,16 +506,13 @@ static int netcons_netpoll_setup(struct netconsole_target *nt)
 		rtnl_lock();
 	}
 
-	if (netcons_local_ip_unset(nt)) {
-		if (!nt->ipv6) {
-			err = netcons_take_ipv4(nt, ndev);
-			if (err)
-				goto put;
-		} else {
+	if (nt->local_ip.family == AF_UNSPEC) {
+		if (nt->remote_ip.family == AF_INET6)
 			err = netcons_take_ipv6(nt, ndev);
-			if (err)
-				goto put;
-		}
+		else
+			err = netcons_take_ipv4(nt, ndev);
+		if (err)
+			goto put;
 		ip_overwritten = true;
 	}
 
@@ -716,22 +694,22 @@ static void netconsole_print_banner(struct netconsole_target *nt)
 	struct netpoll *np = &nt->np;
 
 	np_info(np, "local port %d\n", nt->local_port);
-	if (nt->ipv6)
+	if (nt->local_ip.family == AF_INET6)
 		np_info(np, "local IPv6 address %pI6c\n", &nt->local_ip.in6);
 	else
 		np_info(np, "local IPv4 address %pI4\n", &nt->local_ip.ip);
 	np_info(np, "interface name '%s'\n", np->dev_name);
 	np_info(np, "local ethernet address '%pM'\n", np->dev_mac);
 	np_info(np, "remote port %d\n", nt->remote_port);
-	if (nt->ipv6)
+	if (nt->remote_ip.family == AF_INET6)
 		np_info(np, "remote IPv6 address %pI6c\n", &nt->remote_ip.in6);
 	else
 		np_info(np, "remote IPv4 address %pI4\n", &nt->remote_ip.ip);
 	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
- * populated, 1 if IPv6 is populated, and -1 upon failure.
+/* Parse the string and populate the `inet_addr` struct. Return 0 on success
+ * and -1 upon failure.
  */
 static int netpoll_parse_ip_addr(const char *str, struct inet_addr *addr)
 {
@@ -755,7 +733,7 @@ static int netpoll_parse_ip_addr(const char *str, struct inet_addr *addr)
 	    in6_pton(str, len, (void *)&addr->in6, -1, &end) > 0 &&
 	    (!end || *end == 0 || *end == '\n')) {
 		addr->family = AF_INET6;
-		return 1;
+		return 0;
 	}
 
 	return -1;
@@ -861,7 +839,7 @@ static ssize_t local_ip_show(struct config_item *item, char *buf)
 {
 	struct netconsole_target *nt = to_target(item);
 
-	if (nt->ipv6)
+	if (nt->local_ip.family == AF_INET6)
 		return sysfs_emit(buf, "%pI6c\n", &nt->local_ip.in6);
 	else
 		return sysfs_emit(buf, "%pI4\n", &nt->local_ip.ip);
@@ -871,7 +849,7 @@ static ssize_t remote_ip_show(struct config_item *item, char *buf)
 {
 	struct netconsole_target *nt = to_target(item);
 
-	if (nt->ipv6)
+	if (nt->remote_ip.family == AF_INET6)
 		return sysfs_emit(buf, "%pI6c\n", &nt->remote_ip.in6);
 	else
 		return sysfs_emit(buf, "%pI4\n", &nt->remote_ip.ip);
@@ -1219,7 +1197,6 @@ static ssize_t local_ip_store(struct config_item *item, const char *buf,
 {
 	struct netconsole_target *nt = to_target(item);
 	ssize_t ret = -EINVAL;
-	int ipv6;
 
 	dynamic_netconsole_mutex_lock();
 	if (nt->state == STATE_ENABLED) {
@@ -1228,10 +1205,8 @@ static ssize_t local_ip_store(struct config_item *item, const char *buf,
 		goto out_unlock;
 	}
 
-	ipv6 = netpoll_parse_ip_addr(buf, &nt->local_ip);
-	if (ipv6 == -1)
+	if (netpoll_parse_ip_addr(buf, &nt->local_ip) < 0)
 		goto out_unlock;
-	nt->ipv6 = !!ipv6;
 
 	ret = count;
 out_unlock:
@@ -1244,7 +1219,6 @@ static ssize_t remote_ip_store(struct config_item *item, const char *buf,
 {
 	struct netconsole_target *nt = to_target(item);
 	ssize_t ret = -EINVAL;
-	int ipv6;
 
 	dynamic_netconsole_mutex_lock();
 	if (nt->state == STATE_ENABLED) {
@@ -1253,10 +1227,8 @@ static ssize_t remote_ip_store(struct config_item *item, const char *buf,
 		goto out_unlock;
 	}
 
-	ipv6 = netpoll_parse_ip_addr(buf, &nt->remote_ip);
-	if (ipv6 == -1)
+	if (netpoll_parse_ip_addr(buf, &nt->remote_ip) < 0)
 		goto out_unlock;
-	nt->ipv6 = !!ipv6;
 
 	ret = count;
 out_unlock:
@@ -2067,7 +2039,7 @@ static void netpoll_udp_checksum(struct netconsole_target *nt,
 
 	/* check needs to be set, since it will be consumed in csum_partial */
 	udph->check = 0;
-	if (nt->ipv6)
+	if (nt->remote_ip.family == AF_INET6)
 		udph->check = csum_ipv6_magic(&nt->local_ip.in6,
 					      &nt->remote_ip.in6,
 					      udp_len, IPPROTO_UDP,
@@ -2108,7 +2080,7 @@ static void push_eth(struct netconsole_target *nt, struct sk_buff *skb)
 	skb_reset_mac_header(skb);
 	ether_addr_copy(eth->h_source, np->dev->dev_addr);
 	ether_addr_copy(eth->h_dest, nt->remote_mac);
-	if (nt->ipv6)
+	if (nt->remote_ip.family == AF_INET6)
 		eth->h_proto = htons(ETH_P_IPV6);
 	else
 		eth->h_proto = htons(ETH_P_IP);
@@ -2177,7 +2149,7 @@ static int netpoll_send_udp(struct netconsole_target *nt, const char *msg,
 		WARN_ON_ONCE(!irqs_disabled());
 
 	udp_len = len + sizeof(struct udphdr);
-	if (nt->ipv6)
+	if (nt->remote_ip.family == AF_INET6)
 		ip_len = udp_len + sizeof(struct ipv6hdr);
 	else
 		ip_len = udp_len + sizeof(struct iphdr);
@@ -2193,7 +2165,7 @@ static int netpoll_send_udp(struct netconsole_target *nt, const char *msg,
 	skb_put(skb, len);
 
 	push_udp(nt, skb, len);
-	if (nt->ipv6)
+	if (nt->remote_ip.family == AF_INET6)
 		push_ipv6(nt, skb, len);
 	else
 		push_ipv4(nt, skb, len);
@@ -2513,10 +2485,8 @@ __releases(&target_list_lock)
 static int netconsole_parser_cmdline(struct netconsole_target *nt, char *opt)
 {
 	struct netpoll *np = &nt->np;
-	bool ipversion_set = false;
 	char *cur = opt;
 	char *delim;
-	int ipv6;
 
 	if (*cur != '@') {
 		delim = strchr(cur, '@');
@@ -2530,16 +2500,12 @@ static int netconsole_parser_cmdline(struct netconsole_target *nt, char *opt)
 	cur++;
 
 	if (*cur != '/') {
-		ipversion_set = true;
 		delim = strchr(cur, '/');
 		if (!delim)
 			goto parse_failed;
 		*delim = 0;
-		ipv6 = netpoll_parse_ip_addr(cur, &nt->local_ip);
-		if (ipv6 < 0)
+		if (netpoll_parse_ip_addr(cur, &nt->local_ip) < 0)
 			goto parse_failed;
-		else
-			nt->ipv6 = (bool)ipv6;
 		cur = delim;
 	}
 	cur++;
@@ -2581,13 +2547,11 @@ static int netconsole_parser_cmdline(struct netconsole_target *nt, char *opt)
 	if (!delim)
 		goto parse_failed;
 	*delim = 0;
-	ipv6 = netpoll_parse_ip_addr(cur, &nt->remote_ip);
-	if (ipv6 < 0)
+	if (netpoll_parse_ip_addr(cur, &nt->remote_ip) < 0)
 		goto parse_failed;
-	else if (ipversion_set && nt->ipv6 != (bool)ipv6)
+	if (nt->local_ip.family != AF_UNSPEC &&
+	    nt->local_ip.family != nt->remote_ip.family)
 		goto parse_failed;
-	else
-		nt->ipv6 = (bool)ipv6;
 	cur = delim + 1;
 
 	if (*cur != 0) {

-- 
2.55.0