From 6d6c1ba7824022528dbe3e283fafbd0775424128 Mon Sep 17 00:00:00 2001 From: Uday Shankar Date: Wed, 12 Mar 2025 13:51:46 -0600 Subject: [PATCH 1/2] net, treewide: define and use MAC_ADDR_STR_LEN There are a few places in the tree which compute the length of the string representation of a MAC address as 3 * ETH_ALEN - 1. Define a constant for this and use it where relevant. No functionality changes are expected. Signed-off-by: Uday Shankar Reviewed-by: Michal Swiatkowski Acked-by: Johannes Berg Reviewed-by: Breno Leitao Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250312-netconsole-v6-1-3437933e79b8@purestorage.com Signed-off-by: Paolo Abeni --- drivers/net/netconsole.c | 2 +- drivers/nvmem/brcm_nvram.c | 2 +- drivers/nvmem/layouts/u-boot-env.c | 2 +- include/linux/if_ether.h | 3 +++ lib/net_utils.c | 4 +--- net/mac80211/debugfs_sta.c | 7 ++++--- 6 files changed, 11 insertions(+), 9 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 098ea9eb02373..43757b5c02169 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -739,7 +739,7 @@ static ssize_t remote_mac_store(struct config_item *item, const char *buf, if (!mac_pton(buf, remote_mac)) goto out_unlock; - if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n') + if (buf[MAC_ADDR_STR_LEN] && buf[MAC_ADDR_STR_LEN] != '\n') goto out_unlock; memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN); diff --git a/drivers/nvmem/brcm_nvram.c b/drivers/nvmem/brcm_nvram.c index b810df727b446..b4cf245fb2467 100644 --- a/drivers/nvmem/brcm_nvram.c +++ b/drivers/nvmem/brcm_nvram.c @@ -100,7 +100,7 @@ static int brcm_nvram_read_post_process_macaddr(void *context, const char *id, i { u8 mac[ETH_ALEN]; - if (bytes != 3 * ETH_ALEN - 1) + if (bytes != MAC_ADDR_STR_LEN) return -EINVAL; if (!mac_pton(buf, mac)) diff --git a/drivers/nvmem/layouts/u-boot-env.c b/drivers/nvmem/layouts/u-boot-env.c index 731e6f4f12b2b..436426d4e8f91 100644 --- a/drivers/nvmem/layouts/u-boot-env.c +++ b/drivers/nvmem/layouts/u-boot-env.c @@ -37,7 +37,7 @@ static int u_boot_env_read_post_process_ethaddr(void *context, const char *id, i { u8 mac[ETH_ALEN]; - if (bytes != 3 * ETH_ALEN - 1) + if (bytes != MAC_ADDR_STR_LEN) return -EINVAL; if (!mac_pton(buf, mac)) diff --git a/include/linux/if_ether.h b/include/linux/if_ether.h index 8a9792a6427ad..61b7335aa037c 100644 --- a/include/linux/if_ether.h +++ b/include/linux/if_ether.h @@ -19,6 +19,9 @@ #include #include +/* XX:XX:XX:XX:XX:XX */ +#define MAC_ADDR_STR_LEN (3 * ETH_ALEN - 1) + static inline struct ethhdr *eth_hdr(const struct sk_buff *skb) { return (struct ethhdr *)skb_mac_header(skb); diff --git a/lib/net_utils.c b/lib/net_utils.c index 42bb0473fb22f..215cda672fee1 100644 --- a/lib/net_utils.c +++ b/lib/net_utils.c @@ -7,11 +7,9 @@ bool mac_pton(const char *s, u8 *mac) { - size_t maxlen = 3 * ETH_ALEN - 1; int i; - /* XX:XX:XX:XX:XX:XX */ - if (strnlen(s, maxlen) < maxlen) + if (strnlen(s, MAC_ADDR_STR_LEN) < MAC_ADDR_STR_LEN) return false; /* Don't dirty result unless string is valid MAC. */ diff --git a/net/mac80211/debugfs_sta.c b/net/mac80211/debugfs_sta.c index a67a9d3160086..a8948f4d983e5 100644 --- a/net/mac80211/debugfs_sta.c +++ b/net/mac80211/debugfs_sta.c @@ -457,11 +457,12 @@ static ssize_t link_sta_addr_read(struct file *file, char __user *userbuf, size_t count, loff_t *ppos) { struct link_sta_info *link_sta = file->private_data; - u8 mac[3 * ETH_ALEN + 1]; + u8 mac[MAC_ADDR_STR_LEN + 2]; snprintf(mac, sizeof(mac), "%pM\n", link_sta->pub->addr); - return simple_read_from_buffer(userbuf, count, ppos, mac, 3 * ETH_ALEN); + return simple_read_from_buffer(userbuf, count, ppos, mac, + MAC_ADDR_STR_LEN + 1); } LINK_STA_OPS(addr); @@ -1240,7 +1241,7 @@ void ieee80211_sta_debugfs_add(struct sta_info *sta) struct ieee80211_local *local = sta->local; struct ieee80211_sub_if_data *sdata = sta->sdata; struct dentry *stations_dir = sta->sdata->debugfs.subdir_stations; - u8 mac[3*ETH_ALEN]; + u8 mac[MAC_ADDR_STR_LEN + 1]; if (!stations_dir) return; From f8a10bed32f5fbede13a5f22fdc4ab8740ea213a Mon Sep 17 00:00:00 2001 From: Uday Shankar Date: Wed, 12 Mar 2025 13:51:47 -0600 Subject: [PATCH 2/2] netconsole: allow selection of egress interface via MAC address Currently, netconsole has two methods of configuration - module parameter and configfs. The former interface allows for netconsole activation earlier during boot (by specifying the module parameter on the kernel command line), so it is preferred for debugging issues which arise before userspace is up/the configfs interface can be used. The module parameter syntax requires specifying the egress interface name. This requirement makes it hard to use for a couple reasons: - The egress interface name can be hard or impossible to predict. For example, installing a new network card in a system can change the interface names assigned by the kernel. - When constructing the module parameter, one may have trouble determining the original (kernel-assigned) name of the interface (which is the name that should be given to netconsole) if some stable interface naming scheme is in effect. A human can usually look at kernel logs to determine the original name, but this is very painful if automation is constructing the parameter. For these reasons, allow selection of the egress interface via MAC address when configuring netconsole using the module parameter. Update the netconsole documentation with an example of the new syntax. Selection of egress interface by MAC address via configfs is far less interesting (since when this interface can be used, one should be able to easily convert between MAC address and interface name), so it is left unimplemented. Signed-off-by: Uday Shankar Reviewed-by: Breno Leitao Tested-by: Breno Leitao Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250312-netconsole-v6-2-3437933e79b8@purestorage.com Signed-off-by: Paolo Abeni --- Documentation/networking/netconsole.rst | 6 ++- include/linux/netpoll.h | 6 +++ net/core/netpoll.c | 51 +++++++++++++++++++------ 3 files changed, 50 insertions(+), 13 deletions(-) diff --git a/Documentation/networking/netconsole.rst b/Documentation/networking/netconsole.rst index ae82a6337a8d8..ec740ba127976 100644 --- a/Documentation/networking/netconsole.rst +++ b/Documentation/networking/netconsole.rst @@ -47,7 +47,7 @@ following format:: 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) + dev network interface name (eth0) or MAC address tgt-port port for logging agent (6666) tgt-ip IP address for logging agent tgt-macaddr ethernet MAC address for logging agent (broadcast) @@ -64,6 +64,10 @@ or using IPv6:: insmod netconsole netconsole=@/,@fd00:1:2:3::1/ +or using a MAC address to select the egress interface:: + + linux netconsole=4444@10.0.0.1/22:33:44:55:66:77,9353@10.0.0.2/12:34:56:78:9a:bc + It also supports logging to multiple remote agents by specifying parameters for the multiple agents separated by semicolons and the complete string enclosed in "quotes", thusly:: diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h index f6e8abe0b1f19..0477208ed9ffa 100644 --- a/include/linux/netpoll.h +++ b/include/linux/netpoll.h @@ -25,7 +25,13 @@ union inet_addr { struct netpoll { struct net_device *dev; netdevice_tracker dev_tracker; + /* + * Either dev_name or dev_mac can be used to specify the local + * interface - dev_name is used if it is a nonempty string, else + * dev_mac is used. + */ char dev_name[IFNAMSIZ]; + u8 dev_mac[ETH_ALEN]; const char *name; union inet_addr local_ip, remote_ip; diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 3cc3eae9def30..7bc75a4ef5d2a 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -507,7 +507,8 @@ void netpoll_print_options(struct netpoll *np) np_info(np, "local IPv6 address %pI6c\n", &np->local_ip.in6); else np_info(np, "local IPv4 address %pI4\n", &np->local_ip.ip); - np_info(np, "interface '%s'\n", np->dev_name); + 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", np->remote_port); if (np->ipv6) np_info(np, "remote IPv6 address %pI6c\n", &np->remote_ip.in6); @@ -577,11 +578,18 @@ int netpoll_parse_options(struct netpoll *np, char *opt) cur++; if (*cur != ',') { - /* parse out dev name */ + /* parse out dev_name or dev_mac */ if ((delim = strchr(cur, ',')) == NULL) goto parse_failed; *delim = 0; - strscpy(np->dev_name, cur, sizeof(np->dev_name)); + + np->dev_name[0] = '\0'; + eth_broadcast_addr(np->dev_mac); + if (!strchr(cur, ':')) + strscpy(np->dev_name, cur, sizeof(np->dev_name)); + else if (!mac_pton(cur, np->dev_mac)) + goto parse_failed; + cur = delim; } cur++; @@ -695,27 +703,45 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) } EXPORT_SYMBOL_GPL(__netpoll_setup); +/* + * Returns a pointer to a string representation of the identifier used + * to select the egress interface for the given netpoll instance. buf + * must be a buffer of length at least MAC_ADDR_STR_LEN + 1. + */ +static char *egress_dev(struct netpoll *np, char *buf) +{ + if (np->dev_name[0]) + return np->dev_name; + + snprintf(buf, MAC_ADDR_STR_LEN, "%pM", np->dev_mac); + return buf; +} + int netpoll_setup(struct netpoll *np) { + struct net *net = current->nsproxy->net_ns; + char buf[MAC_ADDR_STR_LEN + 1]; struct net_device *ndev = NULL; bool ip_overwritten = false; struct in_device *in_dev; int err; rtnl_lock(); - if (np->dev_name[0]) { - struct net *net = current->nsproxy->net_ns; + if (np->dev_name[0]) ndev = __dev_get_by_name(net, np->dev_name); - } + else if (is_valid_ether_addr(np->dev_mac)) + ndev = dev_getbyhwaddr(net, ARPHRD_ETHER, np->dev_mac); + if (!ndev) { - np_err(np, "%s doesn't exist, aborting\n", np->dev_name); + np_err(np, "%s doesn't exist, aborting\n", egress_dev(np, buf)); err = -ENODEV; goto unlock; } netdev_hold(ndev, &np->dev_tracker, GFP_KERNEL); if (netdev_master_upper_dev_get(ndev)) { - np_err(np, "%s is a slave device, aborting\n", np->dev_name); + np_err(np, "%s is a slave device, aborting\n", + egress_dev(np, buf)); err = -EBUSY; goto put; } @@ -723,7 +749,8 @@ int netpoll_setup(struct netpoll *np) if (!netif_running(ndev)) { unsigned long atmost; - np_info(np, "device %s not up yet, forcing it\n", np->dev_name); + np_info(np, "device %s not up yet, forcing it\n", + egress_dev(np, buf)); err = dev_open(ndev, NULL); @@ -757,7 +784,7 @@ int netpoll_setup(struct netpoll *np) if (!ifa) { put_noaddr: np_err(np, "no IP address for %s, aborting\n", - np->dev_name); + egress_dev(np, buf)); err = -EDESTADDRREQ; goto put; } @@ -788,13 +815,13 @@ int netpoll_setup(struct netpoll *np) } if (err) { np_err(np, "no IPv6 address for %s, aborting\n", - np->dev_name); + egress_dev(np, buf)); goto put; } else np_info(np, "local IPv6 %pI6c\n", &np->local_ip.in6); #else np_err(np, "IPv6 is not supported %s, aborting\n", - np->dev_name); + egress_dev(np, buf)); err = -EINVAL; goto put; #endif