[PATCH net-next v3 0/8] netconsole: Add userdata append support

[PATCH net-next v3 0/8] netconsole: Add userdata append support

[Matthew Wood]

Add the ability to add custom userdata to every outbound netconsole message
as a collection of key/value pairs, allowing users to add metadata to every
netconsole message which can be used for  for tagging, filtering, and
aggregating log messages.

In a previous patch series the ability to prepend the uname release was
added towards the goals above. This patch series builds on that
idea to allow any userdata, keyed by a user provided name, to be
included in netconsole messages.

If CONFIG_NETCONSOLE_DYNAMIC is enabled an additional userdata
directory will be presented in the netconsole configfs tree, allowing
the addition of userdata entries.

    /sys/kernel/config/netconsole/
			<target>/
				enabled
				release
				dev_name
				local_port
				remote_port
				local_ip
				remote_ip
				local_mac
				remote_mac
				userdata/
					<key>/
						value
					<key>/
						value
          ...


v1->v2:
 * Updated netconsole_target docs, kdoc is now clean
v2->v3:
 * Remove inline keyword from to_userdat* functions
 * Break up some lines that exceeded 80 chars
 * Replace typos and remove {} from single line if statement
 * Remove unused variable

Testing for this series is as follows:

Build every patch without CONFIG_NETCONSOLE_DYNAMIC, and also built
with CONFIG_NETCONSOLE_DYNAMIC enabled for every patch after the config
option was added

Test Userdata configfs

    # Adding userdata
    cd /sys/kernel/config/netconsole/ && mkdir cmdline0 && cd cmdline0
    mkdir userdata/release && echo hotfix1 > userdata/release/value
    preview=$(for f in `ls userdata`; do echo $f=$(cat userdata/$f/value); done)
    [[ "$preview" == $'release=hotfix1' ]] && echo pass || echo fail
    mkdir userdata/testing && echo something > userdata/testing/value
    preview=$(for f in `ls userdata`; do echo $f=$(cat userdata/$f/value); done)
    [[ "$preview" == $'release=hotfix1\ntesting=something' ]] && echo pass || echo fail
    #
    # Removing Userdata
    rmdir userdata/testing
    preview=$(for f in `ls userdata`; do echo $f=$(cat userdata/$f/value); done)
    [[ "$preview" == $'release=hotfix1' ]] && echo pass || echo fail
    rmdir userdata/release
    preview=$(for f in `ls userdata`; do echo $f=$(cat userdata/$f/value); done)
    [[ "$preview" == $'' ]] && echo pass || echo fail
    #
    # Adding userdata key with too large of 6.7.0-rc8-virtme,12,481,17954104,-directory name [<54 chars]
    mkdir userdata/testing12345678901234567890123456789012345678901234567890
    [[ $? == 1 ]] && echo pass || echo fail
    #
    # Adding userdata value with too large of value [<200 chars]
    mkdir userdata/testing
    echo `for i in {1..201};do printf "%s" "v";done` > userdata/testing/value
    [[ $? == 1 ]] && echo pass || echo fail
    rmdir userdata/testing

- Output:

    pass
    pass
    pass
    pass
    pass
    mkdir: cannot create directory ‘cmdline0/userdata/testing12345678901234567890123456789012345678901234567890’: File name too long
    pass
    bash: echo: write error: Message too long
    pass

Test netconsole messages (w/ msg fragmentation)

    echo `for i in {1..996};do printf "%s" "v";done` > /dev/kmsg

- Output:

    6.7.0-rc8-virtme,12,484,84321212,-,ncfrag=0/997;vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv6.7.0-rc8-virtme,12,484,84321212,-,ncfrag=952/997;vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Test empty userdatum

    cd /sys/kernel/config/netconsole/ && mkdir cmdline0
    mkdir cmdline0/userdata/empty
    echo test > /dev/kmsg
    rmdir cmdline0/userdata/empty

- Output:

Test netconsole messages (w/o userdata fragmentation)

    cd /sys/kernel/config/netconsole/ && mkdir cmdline0
    mkdir cmdline0/userdata/release && echo hotfix1 > cmdline0/userdata/release/value
    mkdir cmdline0/userdata/testing && echo something > cmdline0/userdata/testing/value
    echo test > /dev/kmsg
    rmdir cmdline0/userdata/release
    rmdir cmdline0/userdata/testing

- Output:
    6.7.0-rc8-virtme,12,500,1646292204,-;test
    release=hotfix1
    testing=something

Test netconsole messages (w/ long body fragmentation)
    cd /sys/kernel/config/netconsole/ && mkdir cmdline0
    mkdir cmdline0/userdata/release && echo hotfix1 > cmdline0/userdata/release/value
    mkdir cmdline0/userdata/testing && echo something > cmdline0/userdata/testing/value
    echo `for i in {1..996};do printf "%s" "v";done` > /dev/kmsg
    rmdir cmdline0/userdata/release
    rmdir cmdline0/userdata/testing

- Output:
    6.7.0-rc8-virtme,12,486,156664417,-,ncfrag=0/1031;vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv6.7.0-rc8-virtme,12,486,156664417,-,ncfrag=950/1031;vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    release=hotfix1
    testing=something

Test netconsole messages (w/ long userdata fragmentation)

    cd /sys/kernel/config/netconsole/ && mkdir cmdline0
    LOREM="Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut"
    for i in {0..5}; do mkdir cmdline0/userdata/value${i} && echo ${LOREM} > cmdline0/userdata/value${i}/value; done
    echo test > /dev/kmsg
    for i in {0..5}; do rmdir cmdline0/userdata/value${i}; done

- Output:
    6.7.0-rc8-virtme,12,487,221763007,-,ncfrag=0/1241;test
    value0=Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut
    value1=Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut
    value2=Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut
    value3=Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut
    value4=Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magn6.7.0-rc8-virtme,12,487,221763007,-,ncfrag=950/1241;a aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut
    value5=Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut


Matthew Wood (8):
  net: netconsole: cleanup formatting lints
  net: netconsole: move netconsole_target config_item to config_group
  net: netconsole: move newline trimming to function
  net: netconsole: add docs for appending netconsole user data
  net: netconsole: add a userdata config_group member to
    netconsole_target
  net: netconsole: cache userdata formatted string in netconsole_target
  net: netconsole: append userdata to netconsole messages
  net: netconsole: append userdata to fragmented netconsole messages

 Documentation/networking/netconsole.rst |  66 +++++
 drivers/net/netconsole.c                | 359 ++++++++++++++++++++----
 2 files changed, 370 insertions(+), 55 deletions(-)

--
2.43.0

[PATCH net-next v3 1/8] net: netconsole: cleanup formatting lints

[Matthew Wood]

Address checkpatch lint suggestions in preparation for later changes

Signed-off-by: Matthew Wood <thepacketgeek@gmail.com>
Reviewed-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/netconsole.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 6e14ba5e06c8..93fc3b509706 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -49,7 +49,7 @@ static char config[MAX_PARAM_LENGTH];
 module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
 MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
 
-static bool oops_only = false;
+static bool oops_only;
 module_param(oops_only, bool, 0600);
 MODULE_PARM_DESC(oops_only, "Only log oops messages");
 
@@ -501,6 +501,7 @@ static ssize_t local_ip_store(struct config_item *item, const char *buf,
 
 	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);
@@ -510,9 +511,9 @@ static ssize_t local_ip_store(struct config_item *item, const char *buf,
 		} else
 			goto out_unlock;
 	} else {
-		if (!nt->np.ipv6) {
+		if (!nt->np.ipv6)
 			nt->np.local_ip.ip = in_aton(buf);
-		} else
+		else
 			goto out_unlock;
 	}
 
@@ -537,6 +538,7 @@ static ssize_t remote_ip_store(struct config_item *item, const char *buf,
 
 	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);
@@ -546,9 +548,9 @@ static ssize_t remote_ip_store(struct config_item *item, const char *buf,
 		} else
 			goto out_unlock;
 	} else {
-		if (!nt->np.ipv6) {
+		if (!nt->np.ipv6)
 			nt->np.remote_ip.ip = in_aton(buf);
-		} else
+		else
 			goto out_unlock;
 	}
 
@@ -781,6 +783,7 @@ static int netconsole_netdev_event(struct notifier_block *this,
 	spin_unlock_irqrestore(&target_list_lock, flags);
 	if (stopped) {
 		const char *msg = "had an event";
+
 		switch (event) {
 		case NETDEV_UNREGISTER:
 			msg = "unregistered";
-- 
2.43.0

[PATCH net-next v3 2/8] net: netconsole: move netconsole_target config_item to config_group

[Matthew Wood]

In order to support a nested userdata config_group in later patches,
use a config_group for netconsole_target instead of a
config_item. It's a no-op functionality-wise, since
config_group maintains all features of a config_item via the cg_item
member.

Signed-off-by: Matthew Wood <thepacketgeek@gmail.com>
Reviewed-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/netconsole.c | 58 +++++++++++++++++++++-------------------
 1 file changed, 31 insertions(+), 27 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 93fc3b509706..12bfb7eaae7f 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -79,7 +79,7 @@ static struct console netconsole_ext;
 /**
  * struct netconsole_target - Represents a configured netconsole target.
  * @list:	Links this target into the target_list.
- * @item:	Links us into the configfs subsystem hierarchy.
+ * @group:	Links us into the configfs subsystem hierarchy.
  * @enabled:	On / off knob to enable / disable target.
  *		Visible from userspace (read-write).
  *		We maintain a strict 1:1 correspondence between this and
@@ -102,7 +102,7 @@ static struct console netconsole_ext;
 struct netconsole_target {
 	struct list_head	list;
 #ifdef	CONFIG_NETCONSOLE_DYNAMIC
-	struct config_item	item;
+	struct config_group	group;
 #endif
 	bool			enabled;
 	bool			extended;
@@ -134,14 +134,14 @@ static void __exit dynamic_netconsole_exit(void)
  */
 static void netconsole_target_get(struct netconsole_target *nt)
 {
-	if (config_item_name(&nt->item))
-		config_item_get(&nt->item);
+	if (config_item_name(&nt->group.cg_item))
+		config_group_get(&nt->group);
 }
 
 static void netconsole_target_put(struct netconsole_target *nt)
 {
-	if (config_item_name(&nt->item))
-		config_item_put(&nt->item);
+	if (config_item_name(&nt->group.cg_item))
+		config_group_put(&nt->group);
 }
 
 #else	/* !CONFIG_NETCONSOLE_DYNAMIC */
@@ -221,9 +221,13 @@ static struct netconsole_target *alloc_and_init(void)
 
 static struct netconsole_target *to_target(struct config_item *item)
 {
-	return item ?
-		container_of(item, struct netconsole_target, item) :
-		NULL;
+	struct config_group *cfg_group;
+
+	cfg_group = to_config_group(item);
+	if (!cfg_group)
+		return NULL;
+	return container_of(to_config_group(item),
+			    struct netconsole_target, group);
 }
 
 /*
@@ -370,7 +374,7 @@ static ssize_t release_store(struct config_item *item, const char *buf,
 	mutex_lock(&dynamic_netconsole_mutex);
 	if (nt->enabled) {
 		pr_err("target (%s) is enabled, disable to update parameters\n",
-		       config_item_name(&nt->item));
+		       config_item_name(&nt->group.cg_item));
 		err = -EINVAL;
 		goto out_unlock;
 	}
@@ -398,7 +402,7 @@ static ssize_t extended_store(struct config_item *item, const char *buf,
 	mutex_lock(&dynamic_netconsole_mutex);
 	if (nt->enabled) {
 		pr_err("target (%s) is enabled, disable to update parameters\n",
-		       config_item_name(&nt->item));
+		       config_item_name(&nt->group.cg_item));
 		err = -EINVAL;
 		goto out_unlock;
 	}
@@ -425,7 +429,7 @@ static ssize_t dev_name_store(struct config_item *item, const char *buf,
 	mutex_lock(&dynamic_netconsole_mutex);
 	if (nt->enabled) {
 		pr_err("target (%s) is enabled, disable to update parameters\n",
-		       config_item_name(&nt->item));
+		       config_item_name(&nt->group.cg_item));
 		mutex_unlock(&dynamic_netconsole_mutex);
 		return -EINVAL;
 	}
@@ -450,7 +454,7 @@ static ssize_t local_port_store(struct config_item *item, const char *buf,
 	mutex_lock(&dynamic_netconsole_mutex);
 	if (nt->enabled) {
 		pr_err("target (%s) is enabled, disable to update parameters\n",
-		       config_item_name(&nt->item));
+		       config_item_name(&nt->group.cg_item));
 		goto out_unlock;
 	}
 
@@ -473,7 +477,7 @@ static ssize_t remote_port_store(struct config_item *item,
 	mutex_lock(&dynamic_netconsole_mutex);
 	if (nt->enabled) {
 		pr_err("target (%s) is enabled, disable to update parameters\n",
-		       config_item_name(&nt->item));
+		       config_item_name(&nt->group.cg_item));
 		goto out_unlock;
 	}
 
@@ -495,7 +499,7 @@ static ssize_t local_ip_store(struct config_item *item, const char *buf,
 	mutex_lock(&dynamic_netconsole_mutex);
 	if (nt->enabled) {
 		pr_err("target (%s) is enabled, disable to update parameters\n",
-		       config_item_name(&nt->item));
+		       config_item_name(&nt->group.cg_item));
 		goto out_unlock;
 	}
 
@@ -532,7 +536,7 @@ static ssize_t remote_ip_store(struct config_item *item, const char *buf,
 	mutex_lock(&dynamic_netconsole_mutex);
 	if (nt->enabled) {
 		pr_err("target (%s) is enabled, disable to update parameters\n",
-		       config_item_name(&nt->item));
+		       config_item_name(&nt->group.cg_item));
 		goto out_unlock;
 	}
 
@@ -570,7 +574,7 @@ static ssize_t remote_mac_store(struct config_item *item, const char *buf,
 	mutex_lock(&dynamic_netconsole_mutex);
 	if (nt->enabled) {
 		pr_err("target (%s) is enabled, disable to update parameters\n",
-		       config_item_name(&nt->item));
+		       config_item_name(&nt->group.cg_item));
 		goto out_unlock;
 	}
 
@@ -638,7 +642,7 @@ static struct netconsole_target *find_cmdline_target(const char *name)
 
 	spin_lock_irqsave(&target_list_lock, flags);
 	list_for_each_entry(nt, &target_list, list) {
-		if (!strcmp(nt->item.ci_name, name)) {
+		if (!strcmp(nt->group.cg_item.ci_name, name)) {
 			ret = nt;
 			break;
 		}
@@ -652,8 +656,8 @@ static struct netconsole_target *find_cmdline_target(const char *name)
  * Group operations and type for netconsole_subsys.
  */
 
-static struct config_item *make_netconsole_target(struct config_group *group,
-						  const char *name)
+static struct config_group *make_netconsole_target(struct config_group *group,
+						   const char *name)
 {
 	struct netconsole_target *nt;
 	unsigned long flags;
@@ -666,7 +670,7 @@ static struct config_item *make_netconsole_target(struct config_group *group,
 		     strlen(NETCONSOLE_PARAM_TARGET_PREFIX))) {
 		nt = find_cmdline_target(name);
 		if (nt)
-			return &nt->item;
+			return &nt->group;
 	}
 
 	nt = alloc_and_init();
@@ -674,14 +678,14 @@ static struct config_item *make_netconsole_target(struct config_group *group,
 		return ERR_PTR(-ENOMEM);
 
 	/* Initialize the config_item member */
-	config_item_init_type_name(&nt->item, name, &netconsole_target_type);
+	config_group_init_type_name(&nt->group, name, &netconsole_target_type);
 
 	/* Adding, but it is disabled */
 	spin_lock_irqsave(&target_list_lock, flags);
 	list_add(&nt->list, &target_list);
 	spin_unlock_irqrestore(&target_list_lock, flags);
 
-	return &nt->item;
+	return &nt->group;
 }
 
 static void drop_netconsole_target(struct config_group *group,
@@ -701,11 +705,11 @@ static void drop_netconsole_target(struct config_group *group,
 	if (nt->enabled)
 		netpoll_cleanup(&nt->np);
 
-	config_item_put(&nt->item);
+	config_item_put(&nt->group.cg_item);
 }
 
 static struct configfs_group_operations netconsole_subsys_group_ops = {
-	.make_item	= make_netconsole_target,
+	.make_group	= make_netconsole_target,
 	.drop_item	= drop_netconsole_target,
 };
 
@@ -731,8 +735,8 @@ static void populate_configfs_item(struct netconsole_target *nt,
 
 	snprintf(target_name, sizeof(target_name), "%s%d",
 		 NETCONSOLE_PARAM_TARGET_PREFIX, cmdline_count);
-	config_item_init_type_name(&nt->item, target_name,
-				   &netconsole_target_type);
+	config_group_init_type_name(&nt->group, target_name,
+				    &netconsole_target_type);
 }
 
 #endif	/* CONFIG_NETCONSOLE_DYNAMIC */
-- 
2.43.0

[PATCH net-next v3 3/8] net: netconsole: move newline trimming to function

[Matthew Wood]

Move newline trimming logic from `dev_name_store()` to a new function
(trim_newline()) for shared use in netconsole.c

Signed-off-by: Matthew Wood <thepacketgeek@gmail.com>
---
 drivers/net/netconsole.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 12bfb7eaae7f..e6c3b15fe95d 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -230,6 +230,16 @@ static struct netconsole_target *to_target(struct config_item *item)
 			    struct netconsole_target, group);
 }
 
+/* Get rid of possible trailing newline, returning the new length */
+static void trim_newline(char *s, size_t maxlen)
+{
+	size_t len;
+
+	len = strnlen(s, maxlen);
+	if (s[len - 1] == '\n')
+		s[len - 1] = '\0';
+}
+
 /*
  * Attribute operations for netconsole_target.
  */
@@ -424,7 +434,6 @@ static ssize_t dev_name_store(struct config_item *item, const char *buf,
 		size_t count)
 {
 	struct netconsole_target *nt = to_target(item);
-	size_t len;
 
 	mutex_lock(&dynamic_netconsole_mutex);
 	if (nt->enabled) {
@@ -435,11 +444,7 @@ static ssize_t dev_name_store(struct config_item *item, const char *buf,
 	}
 
 	strscpy(nt->np.dev_name, buf, IFNAMSIZ);
-
-	/* Get rid of possible trailing newline from echo(1) */
-	len = strnlen(nt->np.dev_name, IFNAMSIZ);
-	if (nt->np.dev_name[len - 1] == '\n')
-		nt->np.dev_name[len - 1] = '\0';
+	trim_newline(nt->np.dev_name, IFNAMSIZ);
 
 	mutex_unlock(&dynamic_netconsole_mutex);
 	return strnlen(buf, count);
-- 
2.43.0

[PATCH net-next v3 4/8] net: netconsole: add docs for appending netconsole user data

[Matthew Wood]

Add a new User Data section to the netconsole docs to describe the
appending of user data capability (for netconsole dynamic configuration)
with usage and netconsole output examples.

Co-developed-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Matthew Wood <thepacketgeek@gmail.com>
---
 Documentation/networking/netconsole.rst | 66 +++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

diff --git a/Documentation/networking/netconsole.rst b/Documentation/networking/netconsole.rst
index 390730a74332..b28c525e5d1e 100644
--- a/Documentation/networking/netconsole.rst
+++ b/Documentation/networking/netconsole.rst
@@ -15,6 +15,8 @@ Extended console support by Tejun Heo <tj@kernel.org>, May 1 2015
 
 Release prepend support by Breno Leitao <leitao@debian.org>, Jul 7 2023
 
+Userdata append support by Matthew Wood <thepacketgeek@gmail.com>, Jan 22 2024
+
 Please send bug reports to Matt Mackall <mpm@selenic.com>
 Satyam Sharma <satyam.sharma@gmail.com>, and Cong Wang <xiyou.wangcong@gmail.com>
 
@@ -171,6 +173,70 @@ You can modify these targets in runtime by creating the following targets::
  cat cmdline1/remote_ip
  10.0.0.3
 
+Append User Data
+----------------
+
+Custom user data can be appended to the end of messages with netconsole
+dynamic configuration enabled. User data entries can be modified without
+changing the "enabled" attribute of a target.
+
+Directories (keys) under `userdata` are limited to 54 character length, and
+data in `userdata/<key>/value` are limited to 200 bytes::
+
+ cd /sys/kernel/config/netconsole && mkdir cmdline0
+ cd cmdline0
+ mkdir userdata/foo
+ echo bar > userdata/foo/value
+ mkdir userdata/qux
+ echo baz > userdata/qux/value
+
+Messages will now include this additional user data::
+
+ echo "This is a message" > /dev/kmsg
+
+Sends::
+
+ 12,607,22085407756,-;This is a message
+ foo=bar
+ qux=baz
+
+Preview the userdata that will be appended with::
+
+ cd /sys/kernel/config/netconsole/cmdline0/userdata
+ for f in `ls userdata`; do echo $f=$(cat userdata/$f/value); done
+
+If a `userdata` entry is created but no data is written to the `value` file,
+the entry will be omitted from netconsole messages::
+
+ cd /sys/kernel/config/netconsole && mkdir cmdline0
+ cd cmdline0
+ mkdir userdata/foo
+ echo bar > userdata/foo/value
+ mkdir userdata/qux
+
+The `qux` key is omitted since it has no value::
+
+ echo "This is a message" > /dev/kmsg
+ 12,607,22085407756,-;This is a message
+ foo=bar
+
+Delete `userdata` entries with `rmdir`::
+
+ rmdir /sys/kernel/config/netconsole/cmdline0/userdata/qux
+
+.. warning::
+   When writing strings to user data values, input is broken up per line in
+   configfs store calls and this can cause confusing behavior::
+
+     mkdir userdata/testing
+     printf "val1\nval2" > userdata/testing/value
+     # userdata store value is called twice, first with "val1\n" then "val2"
+     # so "val2" is stored, being the last value stored
+     cat userdata/testing/value
+     val2
+
+   It is recommended to not write user data values with newlines.
+
 Extended console:
 =================
 
-- 
2.43.0

[PATCH net-next v3 5/8] net: netconsole: add a userdata config_group member to netconsole_target

[Matthew Wood]

Create configfs machinery for netconsole userdata appending, which depends
on CONFIG_NETCONSOLE_DYNAMIC (for configfs interface). Add a userdata
config_group to netconsole_target for managing userdata entries as a tree
under the netconsole configfs subsystem. Directory names created under the
userdata directory become userdatum keys; the userdatum value is the
content of the value file.

Include the minimum-viable-changes for userdata configfs config_group.
init_target_config_group() ties in the complete configfs machinery to
avoid unused func/variable errors during build. Initializing the
netconsole_target->group is moved to init_target_config_group, which
will also init and add the userdata config_group.

Each userdatum entry has a limit of 256 bytes (54 for
the key/directory, 200 for the value, and 2 for '=' and '\n'
characters), which is enforced by the configfs functions for updating
the userdata config_group.

When a new netconsole_target is created, initialize the userdata
config_group and add it as a default group for netconsole_target
config_group, allowing the userdata configfs sub-tree to be presented
in the netconsole configfs tree under the userdata directory.

Co-developed-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Matthew Wood <thepacketgeek@gmail.com>
---
 drivers/net/netconsole.c | 147 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 142 insertions(+), 5 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index e6c3b15fe95d..3618b9ebcce4 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -43,6 +43,10 @@ MODULE_DESCRIPTION("Console driver for network interfaces");
 MODULE_LICENSE("GPL");
 
 #define MAX_PARAM_LENGTH	256
+#define MAX_USERDATA_NAME_LENGTH	54
+#define MAX_USERDATA_VALUE_LENGTH	200
+#define MAX_USERDATA_ENTRY_LENGTH	256
+#define MAX_USERDATA_ITEMS		16
 #define MAX_PRINT_CHUNK		1000
 
 static char config[MAX_PARAM_LENGTH];
@@ -80,6 +84,7 @@ static struct console netconsole_ext;
  * struct netconsole_target - Represents a configured netconsole target.
  * @list:	Links this target into the target_list.
  * @group:	Links us into the configfs subsystem hierarchy.
+ * @userdata_group:	Links to the userdata configfs hierarchy
  * @enabled:	On / off knob to enable / disable target.
  *		Visible from userspace (read-write).
  *		We maintain a strict 1:1 correspondence between this and
@@ -103,6 +108,7 @@ struct netconsole_target {
 	struct list_head	list;
 #ifdef	CONFIG_NETCONSOLE_DYNAMIC
 	struct config_group	group;
+	struct config_group	userdata_group;
 #endif
 	bool			enabled;
 	bool			extended;
@@ -215,6 +221,10 @@ static struct netconsole_target *alloc_and_init(void)
  *				|	remote_ip
  *				|	local_mac
  *				|	remote_mac
+ *				|	userdata/
+ *				|		<key>/
+ *				|			value
+ *				|		...
  *				|
  *				<target>/...
  */
@@ -596,6 +606,123 @@ static ssize_t remote_mac_store(struct config_item *item, const char *buf,
 	return -EINVAL;
 }
 
+struct userdatum {
+	struct config_item item;
+	char value[MAX_USERDATA_VALUE_LENGTH];
+};
+
+static struct userdatum *to_userdatum(struct config_item *item)
+{
+	return container_of(item, struct userdatum, item);
+}
+
+struct userdata {
+	struct config_group group;
+};
+
+static struct userdata *to_userdata(struct config_item *item)
+{
+	return container_of(to_config_group(item), struct userdata, group);
+}
+
+static struct netconsole_target *userdata_to_target(struct userdata *ud)
+{
+	struct config_group *netconsole_group;
+
+	netconsole_group = to_config_group(ud->group.cg_item.ci_parent);
+	return to_target(&netconsole_group->cg_item);
+}
+
+static ssize_t userdatum_value_show(struct config_item *item, char *buf)
+{
+	return sysfs_emit(buf, "%s\n", &(to_userdatum(item)->value[0]));
+}
+
+static ssize_t userdatum_value_store(struct config_item *item, const char *buf,
+				     size_t count)
+{
+	struct userdatum *udm = to_userdatum(item);
+	int ret;
+
+	if (count > MAX_USERDATA_VALUE_LENGTH)
+		return -EMSGSIZE;
+
+	mutex_lock(&dynamic_netconsole_mutex);
+
+	ret = strscpy(udm->value, buf, sizeof(udm->value));
+	if (ret < 0)
+		goto out_unlock;
+	trim_newline(udm->value, sizeof(udm->value));
+
+	mutex_unlock(&dynamic_netconsole_mutex);
+	return count;
+out_unlock:
+	mutex_unlock(&dynamic_netconsole_mutex);
+	return ret;
+}
+
+CONFIGFS_ATTR(userdatum_, value);
+
+static struct configfs_attribute *userdatum_attrs[] = {
+	&userdatum_attr_value,
+	NULL,
+};
+
+static void userdatum_release(struct config_item *item)
+{
+	kfree(to_userdatum(item));
+}
+
+static struct configfs_item_operations userdatum_ops = {
+	.release = userdatum_release,
+};
+
+static const struct config_item_type userdatum_type = {
+	.ct_item_ops	= &userdatum_ops,
+	.ct_attrs	= userdatum_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_item *userdatum_make_item(struct config_group *group,
+					       const char *name)
+{
+	struct netconsole_target *nt;
+	struct userdatum *udm;
+	struct userdata *ud;
+	size_t child_count;
+
+	if (strlen(name) > MAX_USERDATA_NAME_LENGTH)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	ud = to_userdata(&group->cg_item);
+	nt = userdata_to_target(ud);
+	child_count = list_count_nodes(&nt->userdata_group.cg_children);
+	if (child_count >= MAX_USERDATA_ITEMS)
+		return ERR_PTR(-ENOSPC);
+
+	udm = kzalloc(sizeof(*udm), GFP_KERNEL);
+	if (!udm)
+		return ERR_PTR(-ENOMEM);
+
+	config_item_init_type_name(&udm->item, name, &userdatum_type);
+	return &udm->item;
+}
+
+static struct configfs_attribute *userdata_attrs[] = {
+	NULL,
+};
+
+static struct configfs_group_operations userdata_ops = {
+	.make_item		= userdatum_make_item,
+};
+
+static struct config_item_type userdata_type = {
+	.ct_item_ops	= &userdatum_ops,
+	.ct_group_ops	= &userdata_ops,
+	.ct_attrs	= userdata_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
 CONFIGFS_ATTR(, enabled);
 CONFIGFS_ATTR(, extended);
 CONFIGFS_ATTR(, dev_name);
@@ -640,6 +767,15 @@ static const struct config_item_type netconsole_target_type = {
 	.ct_owner		= THIS_MODULE,
 };
 
+static void init_target_config_group(struct netconsole_target *nt,
+				     const char *name)
+{
+	config_group_init_type_name(&nt->group, name, &netconsole_target_type);
+	config_group_init_type_name(&nt->userdata_group, "userdata",
+				    &userdata_type);
+	configfs_add_default_group(&nt->userdata_group, &nt->group);
+}
+
 static struct netconsole_target *find_cmdline_target(const char *name)
 {
 	struct netconsole_target *nt, *ret = NULL;
@@ -674,16 +810,18 @@ static struct config_group *make_netconsole_target(struct config_group *group,
 	if (!strncmp(name, NETCONSOLE_PARAM_TARGET_PREFIX,
 		     strlen(NETCONSOLE_PARAM_TARGET_PREFIX))) {
 		nt = find_cmdline_target(name);
-		if (nt)
+		if (nt) {
+			init_target_config_group(nt, name);
 			return &nt->group;
+		}
 	}
 
 	nt = alloc_and_init();
 	if (!nt)
 		return ERR_PTR(-ENOMEM);
 
-	/* Initialize the config_item member */
-	config_group_init_type_name(&nt->group, name, &netconsole_target_type);
+	/* Initialize the config_group member */
+	init_target_config_group(nt, name);
 
 	/* Adding, but it is disabled */
 	spin_lock_irqsave(&target_list_lock, flags);
@@ -740,8 +878,7 @@ static void populate_configfs_item(struct netconsole_target *nt,
 
 	snprintf(target_name, sizeof(target_name), "%s%d",
 		 NETCONSOLE_PARAM_TARGET_PREFIX, cmdline_count);
-	config_group_init_type_name(&nt->group, target_name,
-				    &netconsole_target_type);
+	init_target_config_group(nt, target_name);
 }
 
 #endif	/* CONFIG_NETCONSOLE_DYNAMIC */
-- 
2.43.0

[PATCH net-next v3 6/8] net: netconsole: cache userdata formatted string in netconsole_target

[Matthew Wood]

Store a formatted string for userdata that will be appended to netconsole
messages. The string has a capacity of 4KB, as calculated by the userdatum
entry length of 256 bytes and a max of 16 userdata entries.

Update the stored netconsole_target->userdata_complete string with the new
formatted userdata values when a userdatum is created, edited, or
removed. Each userdata entry contains a trailing newline, which will be
formatted as such in netconsole messages::

    6.7.0-rc8-virtme,12,500,1646292204,-;test
    release=foo
    something=bar
    6.7.0-rc8-virtme,12,500,1646292204,-;another test
    release=foo
    something=bar

Enforcement of MAX_USERDATA_ITEMS is done in userdatum_make_item;
update_userdata will not check for this case but will skip any userdata
children over the limit of MAX_USERDATA_ITEMs.

If a userdata entry/dir is created but no value is provided, that entry
will be skipped. This is in part because update_userdata() can't be
called in userdatum_make_item() since the item will not have been added
to the userdata config_group children yet. To preserve the experience of
adding an empty userdata that doesn't show up in the netconsole
messages, purposefully skip empty userdata items even when
update_userdata() can be called.

Co-developed-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Matthew Wood <thepacketgeek@gmail.com>
---
 drivers/net/netconsole.c | 61 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 3618b9ebcce4..e4d6ba0b50ef 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -85,6 +85,8 @@ static struct console netconsole_ext;
  * @list:	Links this target into the target_list.
  * @group:	Links us into the configfs subsystem hierarchy.
  * @userdata_group:	Links to the userdata configfs hierarchy
+ * @userdata_complete:	Cached, formatted string of append
+ * @userdata_length:	String length of userdata_complete
  * @enabled:	On / off knob to enable / disable target.
  *		Visible from userspace (read-write).
  *		We maintain a strict 1:1 correspondence between this and
@@ -109,6 +111,8 @@ struct netconsole_target {
 #ifdef	CONFIG_NETCONSOLE_DYNAMIC
 	struct config_group	group;
 	struct config_group	userdata_group;
+	char userdata_complete[MAX_USERDATA_ENTRY_LENGTH * MAX_USERDATA_ITEMS];
+	size_t			userdata_length;
 #endif
 	bool			enabled;
 	bool			extended;
@@ -638,10 +642,48 @@ static ssize_t userdatum_value_show(struct config_item *item, char *buf)
 	return sysfs_emit(buf, "%s\n", &(to_userdatum(item)->value[0]));
 }
 
+static void update_userdata(struct netconsole_target *nt)
+{
+	int complete_idx = 0, child_count = 0;
+	struct list_head *entry;
+
+	/* Clear the current string in case the last userdatum was deleted */
+	nt->userdata_length = 0;
+	nt->userdata_complete[0] = 0;
+
+	list_for_each(entry, &nt->userdata_group.cg_children) {
+		struct userdatum *udm_item;
+		struct config_item *item;
+
+		if (child_count >= MAX_USERDATA_ITEMS)
+			break;
+		child_count++;
+
+		item = container_of(entry, struct config_item, ci_entry);
+		udm_item = to_userdatum(item);
+
+		/* Skip userdata with no value set */
+		if (strnlen(udm_item->value, MAX_USERDATA_VALUE_LENGTH) == 0)
+			continue;
+
+		/* This doesn't overflow userdata_complete since it will write
+		 * one entry length (1/MAX_USERDATA_ITEMS long), entry count is
+		 * checked to not exceed MAX items with child_count above
+		 */
+		complete_idx += scnprintf(&nt->userdata_complete[complete_idx],
+					  MAX_USERDATA_ENTRY_LENGTH, "%s=%s\n",
+					  item->ci_name, udm_item->value);
+	}
+	nt->userdata_length = strnlen(nt->userdata_complete,
+				      sizeof(nt->userdata_complete));
+}
+
 static ssize_t userdatum_value_store(struct config_item *item, const char *buf,
 				     size_t count)
 {
 	struct userdatum *udm = to_userdatum(item);
+	struct netconsole_target *nt;
+	struct userdata *ud;
 	int ret;
 
 	if (count > MAX_USERDATA_VALUE_LENGTH)
@@ -654,6 +696,10 @@ static ssize_t userdatum_value_store(struct config_item *item, const char *buf,
 		goto out_unlock;
 	trim_newline(udm->value, sizeof(udm->value));
 
+	ud = to_userdata(item->ci_parent);
+	nt = userdata_to_target(ud);
+	update_userdata(nt);
+
 	mutex_unlock(&dynamic_netconsole_mutex);
 	return count;
 out_unlock:
@@ -708,12 +754,27 @@ static struct config_item *userdatum_make_item(struct config_group *group,
 	return &udm->item;
 }
 
+static void userdatum_drop(struct config_group *group, struct config_item *item)
+{
+	struct netconsole_target *nt;
+	struct userdata *ud;
+
+	ud = to_userdata(&group->cg_item);
+	nt = userdata_to_target(ud);
+
+	mutex_lock(&dynamic_netconsole_mutex);
+	update_userdata(nt);
+	config_item_put(item);
+	mutex_unlock(&dynamic_netconsole_mutex);
+}
+
 static struct configfs_attribute *userdata_attrs[] = {
 	NULL,
 };
 
 static struct configfs_group_operations userdata_ops = {
 	.make_item		= userdatum_make_item,
+	.drop_item		= userdatum_drop,
 };
 
 static struct config_item_type userdata_type = {
-- 
2.43.0

[PATCH net-next v3 7/8] net: netconsole: append userdata to netconsole messages

[Matthew Wood]

Append userdata to outgoing unfragmented (<1000 bytes) netconsole messages.
When sending messages the userdata string is already formatted and stored
in netconsole_target->userdata_complete.

Always write the outgoing message to buf, so userdata can be appended in
a standard fashion. This is a change from only using buf when the
release needs to be prepended to the message.

Co-developed-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Matthew Wood <thepacketgeek@gmail.com>
---
 drivers/net/netconsole.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index e4d6ba0b50ef..d53bb1172336 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -1034,19 +1034,34 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
 	const char *msg_ready = msg;
 	const char *release;
 	int release_len = 0;
+	int userdata_len = 0;
+	char *userdata = NULL;
+
+#ifdef CONFIG_NETCONSOLE_DYNAMIC
+	userdata = nt->userdata_complete;
+	userdata_len = nt->userdata_length;
+#endif
 
 	if (nt->release) {
 		release = init_utsname()->release;
 		release_len = strlen(release) + 1;
 	}
 
-	if (msg_len + release_len <= MAX_PRINT_CHUNK) {
+	if (msg_len + release_len + userdata_len <= MAX_PRINT_CHUNK) {
 		/* No fragmentation needed */
 		if (nt->release) {
 			scnprintf(buf, MAX_PRINT_CHUNK, "%s,%s", release, msg);
 			msg_len += release_len;
-			msg_ready = buf;
+		} else {
+			memcpy(buf, msg, msg_len);
 		}
+
+		if (userdata)
+			msg_len += scnprintf(&buf[msg_len],
+					     MAX_PRINT_CHUNK - msg_len,
+					     "%s", userdata);
+
+		msg_ready = buf;
 		netpoll_send_udp(&nt->np, msg_ready, msg_len);
 		return;
 	}
-- 
2.43.0

[PATCH net-next v3 8/8] net: netconsole: append userdata to fragmented netconsole messages

[Matthew Wood]

Regardless of whether the original message body or formatted userdata
exceeds the MAX_PRINT_CHUNK, append userdata to the netconsole message
starting with the first chunk that has available space after writing the
body.

Co-developed-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Matthew Wood <thepacketgeek@gmail.com>
---
 drivers/net/netconsole.c | 50 +++++++++++++++++++++++++++++-----------
 1 file changed, 37 insertions(+), 13 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index d53bb1172336..0de108a1c0c8 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -1085,24 +1085,48 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg,
 	memcpy(buf + release_len, header, header_len);
 	header_len += release_len;
 
-	while (offset < body_len) {
+	while (offset < body_len + userdata_len) {
 		int this_header = header_len;
-		int this_chunk;
+		int this_offset = 0;
+		int this_chunk = 0;
 
 		this_header += scnprintf(buf + this_header,
 					 sizeof(buf) - this_header,
-					 ",ncfrag=%d/%d;", offset, body_len);
-
-		this_chunk = min(body_len - offset,
-				 MAX_PRINT_CHUNK - this_header);
-		if (WARN_ON_ONCE(this_chunk <= 0))
-			return;
-
-		memcpy(buf + this_header, body + offset, this_chunk);
-
-		netpoll_send_udp(&nt->np, buf, this_header + this_chunk);
+					 ",ncfrag=%d/%d;", offset,
+					 body_len + userdata_len);
+
+		/* Not all body data has been written yet */
+		if (offset < body_len) {
+			this_chunk = min(body_len - offset,
+					 MAX_PRINT_CHUNK - this_header);
+			if (WARN_ON_ONCE(this_chunk <= 0))
+				return;
+			memcpy(buf + this_header, body + offset, this_chunk);
+			this_offset += this_chunk;
+		}
+		/* Body is fully written and there is pending userdata to write,
+		 * append userdata in this chunk
+		 */
+		if (offset + this_offset >= body_len &&
+		    offset + this_offset < userdata_len + body_len) {
+			int sent_userdata = (offset + this_offset) - body_len;
+			int preceding_bytes = this_chunk + this_header;
+
+			if (WARN_ON_ONCE(sent_userdata < 0))
+				return;
+
+			this_chunk = min(userdata_len - sent_userdata,
+					 MAX_PRINT_CHUNK - preceding_bytes);
+			if (WARN_ON_ONCE(this_chunk <= 0))
+				return;
+			memcpy(buf + this_header + this_offset,
+			       userdata + sent_userdata,
+			       this_chunk);
+			this_offset += this_chunk;
+		}
 
-		offset += this_chunk;
+		netpoll_send_udp(&nt->np, buf, this_header + this_offset);
+		offset += this_offset;
 	}
 }
 
-- 
2.43.0

Re: [PATCH net-next v3 0/8] netconsole: Add userdata append support

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by David S. Miller <davem@davemloft.net>:

On Sun,  4 Feb 2024 15:27:31 -0800 you wrote:
> Add the ability to add custom userdata to every outbound netconsole message
> as a collection of key/value pairs, allowing users to add metadata to every
> netconsole message which can be used for  for tagging, filtering, and
> aggregating log messages.
> 
> In a previous patch series the ability to prepend the uname release was
> added towards the goals above. This patch series builds on that
> idea to allow any userdata, keyed by a user provided name, to be
> included in netconsole messages.
> 
> [...]

Here is the summary with links:
  - [net-next,v3,1/8] net: netconsole: cleanup formatting lints
    https://git.kernel.org/netdev/net-next/c/602ad3b4dd57
  - [net-next,v3,2/8] net: netconsole: move netconsole_target config_item to config_group
    https://git.kernel.org/netdev/net-next/c/bd9c69a36efd
  - [net-next,v3,3/8] net: netconsole: move newline trimming to function
    https://git.kernel.org/netdev/net-next/c/ae001dc67907
  - [net-next,v3,4/8] net: netconsole: add docs for appending netconsole user data
    https://git.kernel.org/netdev/net-next/c/aa7b608d69ea
  - [net-next,v3,5/8] net: netconsole: add a userdata config_group member to netconsole_target
    https://git.kernel.org/netdev/net-next/c/8a6d5fec6c7f
  - [net-next,v3,6/8] net: netconsole: cache userdata formatted string in netconsole_target
    https://git.kernel.org/netdev/net-next/c/df03f830d099
  - [net-next,v3,7/8] net: netconsole: append userdata to netconsole messages
    https://git.kernel.org/netdev/net-next/c/b4ab4f2c0ff5
  - [net-next,v3,8/8] net: netconsole: append userdata to fragmented netconsole messages
    https://git.kernel.org/netdev/net-next/c/1ec9daf95093

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