Merge branch 'netconsole-reuse-netpoll_parse_ip_addr-in-configfs-helpers'

Breno Leitao says:

====================
netconsole: reuse netpoll_parse_ip_addr in configfs helpers

This patchset refactors the IP address parsing logic in the netconsole
driver to eliminate code duplication and improve maintainability. The
changes centralize IPv4 and IPv6 address parsing into a single function
(netpoll_parse_ip_addr). For that, it needs to teach
netpoll_parse_ip_addr() to handle strings with newlines, which is the
type of string coming from configfs.

Background

The netconsole driver currently has duplicate IP address parsing logic
in both local_ip_store() and remote_ip_store() functions. This
duplication increases the risk of inconsistencies and makes the code
harder to maintain.

Benefits

* Reduced code duplication: ~40 lines of duplicate parsing logic
  eliminated
 * Improved robustness: Centralized parsing reduces the chance
   of inconsistencies
 * Easier to maintain: Code follow more the netdev way

v3: https://lore.kernel.org/20250723-netconsole_ref-v3-0-8be9b24e4a99@debian.org
v2: https://lore.kernel.org/20250721-netconsole_ref-v2-0-b42f1833565a@debian.org
v1: https://lore.kernel.org/20250718-netconsole_ref-v1-0-86ef253b7a7a@debian.org
====================

Link: https://patch.msgid.link/20250811-netconsole_ref-v4-0-9c510d8713a2@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 37 insertions, 54 deletions

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index e3722de08ea9..194570443493 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -300,6 +300,33 @@ static void netconsole_print_banner(struct netpoll *np)
 	np_info(np, "remote ethernet address %pM\n", np->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.
+ */
+static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
+{
+	const char *end = NULL;
+	int len;
+
+	len = strlen(str);
+	if (!len)
+		return -1;
+
+	if (str[len - 1] == '\n')
+		len -= 1;
+
+	if (in4_pton(str, len, (void *)addr, -1, &end) > 0 &&
+	    (!end || *end == 0 || *end == '\n'))
+		return 0;
+
+	if (IS_ENABLED(CONFIG_IPV6) &&
+	    in6_pton(str, len, (void *)addr, -1, &end) > 0 &&
+	    (!end || *end == 0 || *end == '\n'))
+		return 1;
+
+	return -1;
+}
+
 #ifdef	CONFIG_NETCONSOLE_DYNAMIC
 
 /*
@@ -730,6 +757,7 @@ 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;
 
 	mutex_lock(&dynamic_netconsole_mutex);
 	if (nt->enabled) {
@@ -738,23 +766,10 @@ static ssize_t local_ip_store(struct config_item *item, const char *buf,
 		goto out_unlock;
 	}
 
-	if (strnchr(buf, count, ':')) {
-		const char *end;
-
-		if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) {
-			if (*end && *end != '\n') {
-				pr_err("invalid IPv6 address at: <%c>\n", *end);
-				goto out_unlock;
-			}
-			nt->np.ipv6 = true;
-		} else
-			goto out_unlock;
-	} else {
-		if (!nt->np.ipv6)
-			nt->np.local_ip.ip = in_aton(buf);
-		else
-			goto out_unlock;
-	}
+	ipv6 = netpoll_parse_ip_addr(buf, &nt->np.local_ip);
+	if (ipv6 == -1)
+		goto out_unlock;
+	nt->np.ipv6 = !!ipv6;
 
 	ret = strnlen(buf, count);
 out_unlock:
@@ -767,6 +782,7 @@ 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;
 
 	mutex_lock(&dynamic_netconsole_mutex);
 	if (nt->enabled) {
@@ -775,23 +791,10 @@ static ssize_t remote_ip_store(struct config_item *item, const char *buf,
 		goto out_unlock;
 	}
 
-	if (strnchr(buf, count, ':')) {
-		const char *end;
-
-		if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) {
-			if (*end && *end != '\n') {
-				pr_err("invalid IPv6 address at: <%c>\n", *end);
-				goto out_unlock;
-			}
-			nt->np.ipv6 = true;
-		} else
-			goto out_unlock;
-	} else {
-		if (!nt->np.ipv6)
-			nt->np.remote_ip.ip = in_aton(buf);
-		else
-			goto out_unlock;
-	}
+	ipv6 = netpoll_parse_ip_addr(buf, &nt->np.remote_ip);
+	if (ipv6 == -1)
+		goto out_unlock;
+	nt->np.ipv6 = !!ipv6;
 
 	ret = strnlen(buf, count);
 out_unlock:
@@ -1742,26 +1745,6 @@ static void write_msg(struct console *con, const char *msg, unsigned int len)
 	spin_unlock_irqrestore(&target_list_lock, flags);
 }
 
-static int netpoll_parse_ip_addr(const char *str, union inet_addr *addr)
-{
-	const char *end;
-
-	if (!strchr(str, ':') &&
-	    in4_pton(str, -1, (void *)addr, -1, &end) > 0) {
-		if (!*end)
-			return 0;
-	}
-	if (in6_pton(str, -1, addr->in6.s6_addr, -1, &end) > 0) {
-#if IS_ENABLED(CONFIG_IPV6)
-		if (!*end)
-			return 1;
-#else
-		return -1;
-#endif
-	}
-	return -1;
-}
-
 static int netconsole_parser_cmdline(struct netpoll *np, char *opt)
 {
 	bool ipversion_set = false;