diff options
| -rw-r--r-- | Documentation/networking/netconsole.txt | 35 | ||||
| -rw-r--r-- | drivers/net/netconsole.c | 141 |
2 files changed, 173 insertions, 3 deletions
diff --git a/Documentation/networking/netconsole.txt b/Documentation/networking/netconsole.txt index a5d574a9ae09..30409a36e95d 100644 --- a/Documentation/networking/netconsole.txt +++ b/Documentation/networking/netconsole.txt @@ -2,6 +2,7 @@ started by Ingo Molnar <mingo@redhat.com>, 2001.09.17 2.6 port and netpoll api by Matt Mackall <mpm@selenic.com>, Sep 9 2003 IPv6 support by Cong Wang <xiyou.wangcong@gmail.com>, Jan 1 2013 +Extended console support by Tejun Heo <tj@kernel.org>, May 1 2015 Please send bug reports to Matt Mackall <mpm@selenic.com> Satyam Sharma <satyam.sharma@gmail.com>, and Cong Wang <xiyou.wangcong@gmail.com> @@ -24,9 +25,10 @@ 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=[+][src-port]@[src-ip]/[<dev>],[tgt-port]@<tgt-ip>/[tgt-macaddr] where + + if present, enable extended console support src-port source for UDP packets (defaults to 6665) src-ip source IP to use (interface address) dev network interface (eth0) @@ -107,6 +109,7 @@ To remove a target: 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) 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) @@ -132,6 +135,36 @@ You can also update the local interface dynamically. This is especially useful if you want to use interfaces that have newly come up (and may not have existed when netconsole was loaded / initialized). +Extended console: +================= + +If '+' is prefixed to the configuration line or "extended" config file +is set to 1, extended console support is enabled. An example boot +param follows. + + linux netconsole=+4444@10.0.0.1/eth1,9353@10.0.0.2/12:34:56:78:9a:bc + +Log messages are transmitted with extended metadata header in the +following format which is the same as /dev/kmsg. + + <level>,<sequnum>,<timestamp>,<contflag>;<message text> + +Non printable characters in <message text> are escaped using "\xff" +notation. If the message contains optional dictionary, verbatim +newline is used as the delimeter. + +If a message doesn't fit in certain number of bytes (currently 1000), +the message is split into multiple fragments by netconsole. These +fragments are transmitted with "ncfrag" header field added. + + ncfrag=<byte-offset>/<total-bytes> + +For example, assuming a lot smaller chunk size, a message "the first +chunk, the 2nd chunk." may be split as follows. + + 6,416,1758426,-,ncfrag=0/31;the first chunk, + 6,416,1758426,-,ncfrag=16/31; the 2nd chunk. + Miscellaneous notes: ==================== diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 9b0c81e7c752..97f3acd44798 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -79,6 +79,12 @@ static LIST_HEAD(target_list); /* This needs to be a spinlock because write_msg() cannot sleep */ static DEFINE_SPINLOCK(target_list_lock); +/* + * Console driver for extended netconsoles. Registered on the first use to + * avoid unnecessarily enabling ext message formatting. + */ +static struct console netconsole_ext; + /** * struct netconsole_target - Represents a configured netconsole target. * @list: Links this target into the target_list. @@ -105,6 +111,7 @@ struct netconsole_target { struct config_item item; #endif bool enabled; + bool extended; struct netpoll np; }; @@ -187,6 +194,11 @@ static struct netconsole_target *alloc_param_target(char *target_config) nt->np.remote_port = 6666; eth_broadcast_addr(nt->np.remote_mac); + if (*target_config == '+') { + nt->extended = true; + target_config++; + } + /* Parse parameters and setup netpoll */ err = netpoll_parse_options(&nt->np, target_config); if (err) @@ -257,6 +269,11 @@ static ssize_t show_enabled(struct netconsole_target *nt, char *buf) return snprintf(buf, PAGE_SIZE, "%d\n", nt->enabled); } +static ssize_t show_extended(struct netconsole_target *nt, char *buf) +{ + return snprintf(buf, PAGE_SIZE, "%d\n", nt->extended); +} + static ssize_t show_dev_name(struct netconsole_target *nt, char *buf) { return snprintf(buf, PAGE_SIZE, "%s\n", nt->np.dev_name); @@ -328,6 +345,11 @@ static ssize_t store_enabled(struct netconsole_target *nt, } if (enabled) { /* true */ + if (nt->extended && !(netconsole_ext.flags & CON_ENABLED)) { + netconsole_ext.flags |= CON_ENABLED; + register_console(&netconsole_ext); + } + /* * Skip netpoll_parse_options() -- all the attributes are * already configured via configfs. Just print them out. @@ -355,6 +377,30 @@ static ssize_t store_enabled(struct netconsole_target *nt, return strnlen(buf, count); } +static ssize_t store_extended(struct netconsole_target *nt, + const char *buf, + size_t count) +{ + int extended; + int err; + + if (nt->enabled) { + pr_err("target (%s) is enabled, disable to update parameters\n", + config_item_name(&nt->item)); + return -EINVAL; + } + + err = kstrtoint(buf, 10, &extended); + if (err < 0) + return err; + if (extended < 0 || extended > 1) + return -EINVAL; + + nt->extended = extended; + + return strnlen(buf, count); +} + static ssize_t store_dev_name(struct netconsole_target *nt, const char *buf, size_t count) @@ -507,6 +553,7 @@ static struct netconsole_target_attr netconsole_target_##_name = \ __CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name) NETCONSOLE_TARGET_ATTR_RW(enabled); +NETCONSOLE_TARGET_ATTR_RW(extended); NETCONSOLE_TARGET_ATTR_RW(dev_name); NETCONSOLE_TARGET_ATTR_RW(local_port); NETCONSOLE_TARGET_ATTR_RW(remote_port); @@ -517,6 +564,7 @@ NETCONSOLE_TARGET_ATTR_RW(remote_mac); static struct configfs_attribute *netconsole_target_attrs[] = { &netconsole_target_enabled.attr, + &netconsole_target_extended.attr, &netconsole_target_dev_name.attr, &netconsole_target_local_port.attr, &netconsole_target_remote_port.attr, @@ -727,6 +775,82 @@ static struct notifier_block netconsole_netdev_notifier = { .notifier_call = netconsole_netdev_event, }; +/** + * send_ext_msg_udp - send extended log message to target + * @nt: target to send message to + * @msg: extended log message to send + * @msg_len: length of message + * + * Transfer extended log @msg to @nt. If @msg is longer than + * MAX_PRINT_CHUNK, it'll be split and transmitted in multiple chunks with + * ncfrag header field added to identify them. + */ +static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, + int msg_len) +{ + static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */ + const char *header, *body; + int offset = 0; + int header_len, body_len; + + if (msg_len <= MAX_PRINT_CHUNK) { + netpoll_send_udp(&nt->np, msg, msg_len); + return; + } + + /* need to insert extra header fields, detect header and body */ + header = msg; + body = memchr(msg, ';', msg_len); + if (WARN_ON_ONCE(!body)) + return; + + header_len = body - header; + body_len = msg_len - header_len - 1; + body++; + + /* + * Transfer multiple chunks with the following extra header. + * "ncfrag=<byte-offset>/<total-bytes>" + */ + memcpy(buf, header, header_len); + + while (offset < body_len) { + int this_header = header_len; + int this_chunk; + + 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); + + offset += this_chunk; + } +} + +static void write_ext_msg(struct console *con, const char *msg, + unsigned int len) +{ + struct netconsole_target *nt; + unsigned long flags; + + if ((oops_only && !oops_in_progress) || list_empty(&target_list)) + return; + + spin_lock_irqsave(&target_list_lock, flags); + list_for_each_entry(nt, &target_list, list) + if (nt->extended && nt->enabled && netif_running(nt->np.dev)) + send_ext_msg_udp(nt, msg, len); + spin_unlock_irqrestore(&target_list_lock, flags); +} + static void write_msg(struct console *con, const char *msg, unsigned int len) { int frag, left; @@ -742,7 +866,7 @@ static void write_msg(struct console *con, const char *msg, unsigned int len) spin_lock_irqsave(&target_list_lock, flags); list_for_each_entry(nt, &target_list, list) { - if (nt->enabled && netif_running(nt->np.dev)) { + if (!nt->extended && nt->enabled && netif_running(nt->np.dev)) { /* * We nest this inside the for-each-target loop above * so that we're able to get as much logging out to @@ -761,6 +885,12 @@ static void write_msg(struct console *con, const char *msg, unsigned int len) spin_unlock_irqrestore(&target_list_lock, flags); } +static struct console netconsole_ext = { + .name = "netcon_ext", + .flags = CON_EXTENDED, /* starts disabled, registered on first use */ + .write = write_ext_msg, +}; + static struct console netconsole = { .name = "netcon", .flags = CON_ENABLED, @@ -783,7 +913,11 @@ static int __init init_netconsole(void) goto fail; } /* Dump existing printks when we register */ - netconsole.flags |= CON_PRINTBUFFER; + if (nt->extended) + netconsole_ext.flags |= CON_PRINTBUFFER | + CON_ENABLED; + else + netconsole.flags |= CON_PRINTBUFFER; spin_lock_irqsave(&target_list_lock, flags); list_add(&nt->list, &target_list); @@ -799,6 +933,8 @@ static int __init init_netconsole(void) if (err) goto undonotifier; + if (netconsole_ext.flags & CON_ENABLED) + register_console(&netconsole_ext); register_console(&netconsole); pr_info("network logging started\n"); @@ -827,6 +963,7 @@ static void __exit cleanup_netconsole(void) { struct netconsole_target *nt, *tmp; + unregister_console(&netconsole_ext); unregister_console(&netconsole); dynamic_netconsole_exit(); unregister_netdevice_notifier(&netconsole_netdev_notifier); |