linux-yocto/include/linux/netpoll.h
Uday Shankar f8a10bed32 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 <ushankar@purestorage.com>
Reviewed-by: Breno Leitao <leitao@debian.org>
Tested-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250312-netconsole-v6-2-3437933e79b8@purestorage.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-03-19 19:17:58 +01:00

122 lines
2.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Common code for low-level network console, dump, and debugger code
*
* Derived from netconsole, kgdb-over-ethernet, and netdump patches
*/
#ifndef _LINUX_NETPOLL_H
#define _LINUX_NETPOLL_H
#include <linux/netdevice.h>
#include <linux/interrupt.h>
#include <linux/rcupdate.h>
#include <linux/list.h>
#include <linux/refcount.h>
union inet_addr {
__u32 all[4];
__be32 ip;
__be32 ip6[4];
struct in_addr in;
struct in6_addr in6;
};
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;
bool ipv6;
u16 local_port, remote_port;
u8 remote_mac[ETH_ALEN];
struct sk_buff_head skb_pool;
struct work_struct refill_wq;
};
struct netpoll_info {
refcount_t refcnt;
struct semaphore dev_lock;
struct sk_buff_head txq;
struct delayed_work tx_work;
struct netpoll *netpoll;
struct rcu_head rcu;
};
#ifdef CONFIG_NETPOLL
void netpoll_poll_dev(struct net_device *dev);
void netpoll_poll_disable(struct net_device *dev);
void netpoll_poll_enable(struct net_device *dev);
#else
static inline void netpoll_poll_disable(struct net_device *dev) { return; }
static inline void netpoll_poll_enable(struct net_device *dev) { return; }
#endif
int netpoll_send_udp(struct netpoll *np, const char *msg, int len);
void netpoll_print_options(struct netpoll *np);
int netpoll_parse_options(struct netpoll *np, char *opt);
int __netpoll_setup(struct netpoll *np, struct net_device *ndev);
int netpoll_setup(struct netpoll *np);
void __netpoll_cleanup(struct netpoll *np);
void __netpoll_free(struct netpoll *np);
void netpoll_cleanup(struct netpoll *np);
void do_netpoll_cleanup(struct netpoll *np);
netdev_tx_t netpoll_send_skb(struct netpoll *np, struct sk_buff *skb);
#ifdef CONFIG_NETPOLL
static inline void *netpoll_poll_lock(struct napi_struct *napi)
{
struct net_device *dev = napi->dev;
if (dev && rcu_access_pointer(dev->npinfo)) {
int owner = smp_processor_id();
while (cmpxchg(&napi->poll_owner, -1, owner) != -1)
cpu_relax();
return napi;
}
return NULL;
}
static inline void netpoll_poll_unlock(void *have)
{
struct napi_struct *napi = have;
if (napi)
smp_store_release(&napi->poll_owner, -1);
}
static inline bool netpoll_tx_running(struct net_device *dev)
{
return irqs_disabled();
}
#else
static inline void *netpoll_poll_lock(struct napi_struct *napi)
{
return NULL;
}
static inline void netpoll_poll_unlock(void *have)
{
}
static inline bool netpoll_tx_running(struct net_device *dev)
{
return false;
}
#endif
#endif