On Fri, Oct 2, 2015 at 2:00 PM, Oren Laadan <orenl@xxxxxxxxxxx> wrote:
>
>
> On Wed, Sep 9, 2015 at 2:53 PM, Michael J. Coss <
> michael.coss@xxxxxxxxxxxxxxxxxx> wrote:
>
>> Adds capability to allow userspace programs to forward a given event to
>> a specific network namespace as determined by the provided pid. In
>> addition, support for a per-namespace kobject_sequence counter was
>> added. Sysfs was modified to return the correct event counter based on
>> the current network namespace.
>>
>> Signed-off-by: Michael J. Coss <michael.coss@xxxxxxxxxxxxxxxxxx>
>> ---
>> include/linux/kobject.h | 3 ++
>> include/net/net_namespace.h | 3 ++
>> kernel/ksysfs.c | 12 ++++++
>> lib/kobject_uevent.c | 90
>> +++++++++++++++++++++++++++++++++++++++++++++
>> 4 files changed, 108 insertions(+)
>>
>> diff --git a/include/linux/kobject.h b/include/linux/kobject.h
>> index 637f670..d1bb509 100644
>> --- a/include/linux/kobject.h
>> +++ b/include/linux/kobject.h
>> @@ -215,6 +215,9 @@ extern struct kobject *firmware_kobj;
>> int kobject_uevent(struct kobject *kobj, enum kobject_action action);
>> int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
>> char *envp[]);
>> +#if defined(CONFIG_UDEVNS) || defined(CONFIG_UDEVNS_MODULE)
>> +int kobject_uevent_forward(char *buf, size_t len, pid_t pid);
>> +#endif
>>
>> __printf(2, 3)
>> int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...);
>> diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
>> index e951453..a4013e5 100644
>> --- a/include/net/net_namespace.h
>> +++ b/include/net/net_namespace.h
>> @@ -134,6 +134,9 @@ struct net {
>> #if IS_ENABLED(CONFIG_MPLS)
>> struct netns_mpls mpls;
>> #endif
>> +#if defined(CONFIG_UDEVNS) || defined(CONFIG_UDEVNS_MODULE)
>> + u64 kevent_seqnum;
>> +#endif
>> struct sock *diag_nlsk;
>> atomic_t fnhe_genid;
>> };
>> diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
>> index 6683cce..4bc15fd 100644
>> --- a/kernel/ksysfs.c
>> +++ b/kernel/ksysfs.c
>> @@ -21,6 +21,9 @@
>> #include <linux/compiler.h>
>>
>> #include <linux/rcupdate.h> /* rcu_expedited */
>> +#if defined(CONFIG_UDEVNS) || defined(CONFIG_UDEVNS_MODULE)
>> +#include <net/net_namespace.h>
>> +#endif
>>
>> #define KERNEL_ATTR_RO(_name) \
>> static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
>> @@ -33,6 +36,15 @@ static struct kobj_attribute _name##_attr = \
>> static ssize_t uevent_seqnum_show(struct kobject *kobj,
>> struct kobj_attribute *attr, char *buf)
>> {
>> +#if defined(CONFIG_UDEVNS) || defined(CONFIG_UDEVNS_MODULE)
>> + pid_t p = task_pid_vnr(current);
>> + struct net *n = get_net_ns_by_pid(p);
>> +
>> + if (n != ERR_PTR(-ESRCH)) {
>> + if (!net_eq(n, &init_net))
>> + return sprintf(buf, "%llu\n", n->kevent_seqnum);
>> + }
>> +#endif
>> return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
>> }
>> KERNEL_ATTR_RO(uevent_seqnum);
>> diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
>> index d791e33..7589745 100644
>> --- a/lib/kobject_uevent.c
>> +++ b/lib/kobject_uevent.c
>> @@ -379,6 +379,96 @@ int kobject_uevent(struct kobject *kobj, enum
>> kobject_action action)
>> }
>> EXPORT_SYMBOL_GPL(kobject_uevent);
>>
>> +#if defined(CONFIG_UDEVNS) || defined(CONFIG_UDEVNS_MODULE)
>> +/**
>> + * kobject_uevent_forward - forward event to specified network namespace
>> + *
>> + * @buf: event buffer
>> + * @len: event length
>> + * @pid: pid of network namespace
>> + *
>> + * Returns 0 if kobject_uevent_forward() is completed with success or the
>> + * corresponding error when it fails.
>> + */
>> +int kobject_uevent_forward(char *buf, size_t len, pid_t pid)
>> +{
>> + int retval = 0;
>> +#if defined(CONFIG_NET)
>> + struct uevent_sock *ue_sk;
>> + struct net *pns;
>> + char *p;
>> + u64 num;
>> +
>> + /* grab the network namespace of the provided pid */
>> + pns = get_net_ns_by_pid(pid);
>> + if (pns == ERR_PTR(-ESRCH))
>> + return -ESRCH;
>> +
>> + /* find sequence number in buffer */
>> + p = buf;
>> + num = 0;
>> + while (p < (buf + len)) {
>> + if (strncmp(p, "SEQNUM=", 7) == 0) {
>> + int r;
>> +
>> + p += 7;
>> + r = kstrtoull(p, 10, &num);
>> + if (r) {
>> + put_net(pns);
>> + return r;
>> + }
>> + break;
>> + }
>> + p += (strlen(p) + 1);
>> + }
>> +
>> + /* if we didn't see a valid seqnum, or none was present, return
>> error */
>> + if (num == 0) {
>> + put_net(pns);
>> + return -EINVAL;
>> + }
>> + /* update per namespace sequence number as needed */
>> + if (pns->kevent_seqnum < num)
>> + pns->kevent_seqnum = num;
>> +
>> + list_for_each_entry(ue_sk, &uevent_sock_list, list) {
>> + struct sock *uevent_sock = ue_sk->sk;
>> + struct sk_buff *skb;
>> +
>> + if (!netlink_has_listeners(uevent_sock, 1))
>> + continue;
>> + /*
>> + * only send to sockets share the same network namespace
>> + * as the passed pid
>> + */
>> + if (!net_eq(sock_net(uevent_sock), pns))
>> + continue;
>> +
>> + /* allocate message with the maximum possible size */
>> + skb = alloc_skb(len, GFP_KERNEL);
>> + if (skb) {
>> + char *p;
>> +
>> + p = skb_put(skb, len);
>> + memcpy(p, buf, len);
>> + NETLINK_CB(skb).dst_group = 1;
>> + retval = netlink_broadcast(uevent_sock, skb, 0, 1,
>> + GFP_KERNEL);
>> +
>> + /* ENOBUFS should be handled in userspace */
>> + if (retval == -ENOBUFS || retval == -ESRCH)
>> + retval = 0;
>>
>
> This may mask an error from an earlier send (to a distinct listener
> socket). Instead, we should retain and report either the first error seen
> or some error seen.
>
>
Ok, scratch that:
I see the model function kobject_uevent_env() does the same thing;
and returning a meaningful error on a broadcast is questionable anyway...
Oren.
_______________________________________________
Containers mailing list
Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/containers
