On 12/4/16, 2:31 PM, Felix Jia wrote:
> Removed the rtnl lock and switch to use RCU lock to iterate through
> the netdev list.
>
> The address generation mode for IPv6 link-local can only be configured
> by netlink messages. This patch adds the ability to change the address
> generation mode via sysctl.
>
> An possible improvement is to remove the addrgenmode variable from the
> idev structure and use the systcl storage for the flag.
>
> The patch is based from v4.9-rc7 in mainline.
>
> Signed-off-by: Felix Jia <felix....@alliedtelesis.co.nz>
> Cc: Carl Smith <carl.sm...@alliedtelesis.co.nz>
> ---
> include/linux/ipv6.h | 1 +
> include/uapi/linux/ipv6.h | 1 +
> net/ipv6/addrconf.c | 73
> ++++++++++++++++++++++++++++++++++++++++++++++-
> 3 files changed, 74 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
> index a064997..0d9e5d4 100644
> --- a/include/linux/ipv6.h
> +++ b/include/linux/ipv6.h
> @@ -64,6 +64,7 @@ struct ipv6_devconf {
> } stable_secret;
> __s32 use_oif_addrs_only;
> __s32 keep_addr_on_down;
> + __s32 addrgenmode;
>
> struct ctl_table_header *sysctl_header;
> };
> diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
> index 8c27723..0524e2c 100644
> --- a/include/uapi/linux/ipv6.h
> +++ b/include/uapi/linux/ipv6.h
> @@ -178,6 +178,7 @@ enum {
> DEVCONF_DROP_UNSOLICITED_NA,
> DEVCONF_KEEP_ADDR_ON_DOWN,
> DEVCONF_RTR_SOLICIT_MAX_INTERVAL,
> + DEVCONF_ADDRGENMODE,
> DEVCONF_MAX
> };
>
> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> index 4bc5ba3..2b83cc7 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -238,6 +238,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
> .use_oif_addrs_only = 0,
> .ignore_routes_with_linkdown = 0,
> .keep_addr_on_down = 0,
> + .addrgenmode = IN6_ADDR_GEN_MODE_EUI64,
> };
>
> static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
> @@ -284,6 +285,7 @@ static struct ipv6_devconf ipv6_devconf_dflt
> __read_mostly = {
> .use_oif_addrs_only = 0,
> .ignore_routes_with_linkdown = 0,
> .keep_addr_on_down = 0,
> + .addrgenmode = IN6_ADDR_GEN_MODE_EUI64,
> };
>
> /* Check if a valid qdisc is available */
> @@ -378,7 +380,7 @@ static struct inet6_dev *ipv6_add_dev(struct net_device
> *dev)
> if (ndev->cnf.stable_secret.initialized)
> ndev->addr_gen_mode = IN6_ADDR_GEN_MODE_STABLE_PRIVACY;
> else
> - ndev->addr_gen_mode = IN6_ADDR_GEN_MODE_EUI64;
> + ndev->addr_gen_mode = ipv6_devconf_dflt.addrgenmode;
>
> ndev->cnf.mtu6 = dev->mtu;
> ndev->nd_parms = neigh_parms_alloc(dev, &nd_tbl);
> @@ -4950,6 +4952,7 @@ static inline void ipv6_store_devconf(struct
> ipv6_devconf *cnf,
> array[DEVCONF_DROP_UNICAST_IN_L2_MULTICAST] =
> cnf->drop_unicast_in_l2_multicast;
> array[DEVCONF_DROP_UNSOLICITED_NA] = cnf->drop_unsolicited_na;
> array[DEVCONF_KEEP_ADDR_ON_DOWN] = cnf->keep_addr_on_down;
> + array[DEVCONF_ADDRGENMODE] = cnf->addrgenmode;
> }
>
> static inline size_t inet6_ifla6_size(void)
> @@ -5496,6 +5499,67 @@ int addrconf_sysctl_mtu(struct ctl_table *ctl, int
> write,
> return proc_dointvec_minmax(&lctl, write, buffer, lenp, ppos);
> }
>
> +static void addrconf_addrgenmode_change(struct net *net)
> +{
> + struct net_device *dev;
> + struct inet6_dev *idev;
> +
> + rcu_read_lock();
> + for_each_netdev_rcu(net, dev) {
> + idev = __in6_dev_get(dev);
> + if (idev) {
> + idev->cnf.addrgenmode = ipv6_devconf_dflt.addrgenmode;
> + idev->addr_gen_mode = ipv6_devconf_dflt.addrgenmode;
> + addrconf_dev_config(idev->dev);
> + }
> + }
> + rcu_read_unlock();
> +}
> +
> +static int addrconf_sysctl_addrgenmode(struct ctl_table *ctl, int write,
> + void __user
> *buffer, size_t *lenp, loff_t *ppos)
> +{
> + int ret;
> + int new_val;
> + struct inet6_dev *idev = (struct inet6_dev *)ctl->extra1;
> + struct net *net = (struct net *)ctl->extra2;
> +
> + if (write) { /* sysctl write request */
> + ret = proc_dointvec(ctl, write, buffer, lenp, ppos);
> + new_val = *((int *)ctl->data);
> +
>
unless I missed it, I don't see a check for valid values for new_val.
The netlink attribute is checked for valid values in the existing equivalent
netlink code.
