Create a new netconsole runtime option that prepends the kernel version in the netconsole message. This is useful to map kernel messages to kernel version in a simple way, i.e., without checking somewhere which kernel version the host that sent the message is using. If this option is selected, then the "<release>," is prepended before the netconsole message. This is an example of a netconsole output, with release feature enabled: 6.4.0-01762-ga1ba2ffe946e;12,426,112883998,-;this is a test Calvin Owens send a RFC about this problem in 2016[1], but his approach was a bit more intrusive, changing the printk subsystem. This approach is lighter, and just append the information in the last mile, just before netconsole push the message to netpoll. [1] Link: https://lore.kernel.org/all/51047c0f6e86abcb9ee13f60653b6946f8fcfc99.1463172791.git.calvinowens@xxxxxx/ Cc: Dave Jones <davej@xxxxxxxxxxxxxxxxx> Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx> --- V1 -> V2: * Configured at runtime instead of at compilation time * Reuse send_ext_msg_udp to avoid extra memory allocation --- Documentation/networking/netconsole.rst | 11 +++- drivers/net/netconsole.c | 80 ++++++++++++++++++++++++- 2 files changed, 87 insertions(+), 4 deletions(-) diff --git a/Documentation/networking/netconsole.rst b/Documentation/networking/netconsole.rst index dd0518e002f6..7a9de0568e84 100644 --- a/Documentation/networking/netconsole.rst +++ b/Documentation/networking/netconsole.rst @@ -13,6 +13,8 @@ IPv6 support by Cong Wang <xiyou.wangcong@xxxxxxxxx>, Jan 1 2013 Extended console support by Tejun Heo <tj@xxxxxxxxxx>, May 1 2015 +Release prepend support by Breno Leitao <leitao@xxxxxxxxxx>, Jul 7 2023 + Please send bug reports to Matt Mackall <mpm@xxxxxxxxxxx> Satyam Sharma <satyam.sharma@xxxxxxxxx>, and Cong Wang <xiyou.wangcong@xxxxxxxxx> @@ -34,10 +36,11 @@ Sender and receiver configuration: It takes a string configuration parameter "netconsole" in the following format:: - netconsole=[+][src-port]@[src-ip]/[<dev>],[tgt-port]@<tgt-ip>/[tgt-macaddr] + netconsole=[+][r][src-port]@[src-ip]/[<dev>],[tgt-port]@<tgt-ip>/[tgt-macaddr] where + if present, enable extended console support + r if present, prepend kernel version (release) to the message src-port source for UDP packets (defaults to 6665) src-ip source IP to use (interface address) dev network interface (eth0) @@ -125,6 +128,7 @@ The interface exposes these parameters of a netconsole target to userspace: ============== ================================= ============ enabled Is this target currently enabled? (read-write) extended Extended mode enabled (read-write) + release Prepend kernel release to message (read-write) dev_name Local network interface name (read-write) local_port Source UDP port to use (read-write) remote_port Remote agent's UDP port (read-write) @@ -165,6 +169,11 @@ following format which is the same as /dev/kmsg:: <level>,<sequnum>,<timestamp>,<contflag>;<message text> +If 'r' (release) feature is enabled, the kernel release version is +prepended to the start of the message. Example:: + + 6.4.0,6,444,501151268,-;netconsole: network logging started + Non printable characters in <message text> are escaped using "\xff" notation. If the message contains optional dictionary, verbatim newline is used as the delimiter. diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 4f4f79532c6c..a72f471ddf02 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -36,6 +36,7 @@ #include <linux/inet.h> #include <linux/configfs.h> #include <linux/etherdevice.h> +#include <linux/utsname.h> MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@xxxxxxxxxxx>"); MODULE_DESCRIPTION("Console driver for network interfaces"); @@ -84,6 +85,8 @@ static struct console netconsole_ext; * Also, other parameters of a target may be modified at * runtime only when it is disabled (enabled == 0). * @extended: Denotes whether console is extended or not. + * @release: Denotes whether kernel release version should be prepended + * to the message. Depends on extended console. * @np: The netpoll structure for this target. * Contains the other userspace visible parameters: * dev_name (read-write) @@ -101,6 +104,7 @@ struct netconsole_target { #endif bool enabled; bool extended; + bool release; struct netpoll np; }; @@ -188,6 +192,14 @@ static struct netconsole_target *alloc_param_target(char *target_config) target_config++; } + if (*target_config == 'r') { + if (!nt->extended) + pr_err("Not enabling release feature, since extended message is disabled\n"); + else + nt->release = true; + target_config++; + } + /* Parse parameters and setup netpoll */ err = netpoll_parse_options(&nt->np, target_config); if (err) @@ -222,6 +234,7 @@ static void free_param_target(struct netconsole_target *nt) * | * <target>/ * | enabled + * | release * | dev_name * | local_port * | remote_port @@ -254,6 +267,11 @@ static ssize_t extended_show(struct config_item *item, char *buf) return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->extended); } +static ssize_t release_show(struct config_item *item, char *buf) +{ + return snprintf(buf, PAGE_SIZE, "%d\n", to_target(item)->release); +} + static ssize_t dev_name_show(struct config_item *item, char *buf) { return snprintf(buf, PAGE_SIZE, "%s\n", to_target(item)->np.dev_name); @@ -332,6 +350,11 @@ static ssize_t enabled_store(struct config_item *item, } if (enabled) { /* true */ + if (nt->release && !nt->extended) { + pr_err("release feature requires extended log message\n"); + goto out_unlock; + } + if (nt->extended && !console_is_registered(&netconsole_ext)) register_console(&netconsole_ext); @@ -366,6 +389,38 @@ static ssize_t enabled_store(struct config_item *item, return err; } +static ssize_t release_store(struct config_item *item, const char *buf, + size_t count) +{ + struct netconsole_target *nt = to_target(item); + int release; + int err; + + mutex_lock(&dynamic_netconsole_mutex); + if (nt->enabled) { + pr_err("target (%s) is enabled, disable to update parameters\n", + config_item_name(&nt->item)); + err = -EINVAL; + goto out_unlock; + } + + err = kstrtoint(buf, 10, &release); + if (err < 0) + goto out_unlock; + if (release < 0 || release > 1) { + err = -EINVAL; + goto out_unlock; + } + + nt->release = release; + + mutex_unlock(&dynamic_netconsole_mutex); + return strnlen(buf, count); +out_unlock: + mutex_unlock(&dynamic_netconsole_mutex); + return err; +} + static ssize_t extended_store(struct config_item *item, const char *buf, size_t count) { @@ -576,10 +631,12 @@ CONFIGFS_ATTR(, local_ip); CONFIGFS_ATTR(, remote_ip); CONFIGFS_ATTR_RO(, local_mac); CONFIGFS_ATTR(, remote_mac); +CONFIGFS_ATTR(, release); static struct configfs_attribute *netconsole_target_attrs[] = { &attr_enabled, &attr_extended, + &attr_release, &attr_dev_name, &attr_local_port, &attr_remote_port, @@ -772,9 +829,23 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, const char *header, *body; int offset = 0; int header_len, body_len; + const char *msg_ready = msg; + const char *release; + int release_len = 0; + + if (nt->release) { + release = init_utsname()->release; + release_len = strlen(release) + 1; + } - if (msg_len <= MAX_PRINT_CHUNK) { - netpoll_send_udp(&nt->np, msg, msg_len); + if (msg_len + release_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; + } + netpoll_send_udp(&nt->np, msg_ready, msg_len); return; } @@ -792,7 +863,10 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, * Transfer multiple chunks with the following extra header. * "ncfrag=<byte-offset>/<total-bytes>" */ - memcpy(buf, header, header_len); + if (nt->release) + scnprintf(buf, MAX_PRINT_CHUNK, "%s,", release); + memcpy(buf + release_len, header, header_len); + header_len += release_len; while (offset < body_len) { int this_header = header_len; -- 2.34.1
