[PATCH net-next v2] ppp: add IFLA_PPP_UNIT netlink attribute
From: Martin Olivier <hidden>
Date: 2026-03-14 01:17:47
Also in:
lkml
Subsystem:
networking drivers, ppp protocol drivers and compressors, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Currently, the PPP rtnetlink API allows creating a new network interface with a custom ifname, but it lacks the ability to specify a custom PPP unit id. Setting a specific unit id is currently only possible with the PPPIOCNEWUNIT ioctl. If a user-space program also requires a custom interface name, it must create the interface first with PPPIOCNEWUNIT and then rename it. Resolve this by introducing the IFLA_PPP_UNIT netlink attribute. This allows user-space programs to atomically request both a custom ifname and a specific PPP unit id during the RTM_NEWLINK creation process, eliminating the post-creation renaming for this use case. Signed-off-by: Martin Olivier <redacted> --- Changes in v2: - use nl policy to set IFLA_PPP_UNIT min allowed value instead of a manual check in ppp_nl_validate() - use of nla_get_s32_default() to collect IFLA_PPP_UNIT value Link to v1: https://lore.kernel.org/netdev/PAWP192MB2411A5E7D3BE1B55E155A92F9747A@PAWP192MB2411.EURP192.PROD.OUTLOOK.COM/ (local) --- drivers/net/ppp/ppp_generic.c | 3 ++- include/uapi/linux/if_link.h | 1 + tools/include/uapi/linux/if_link.h | 1 + 3 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index e9b41777be80..3d5d5fe8bad3 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c@@ -1292,6 +1292,7 @@ static int ppp_dev_configure(struct net *src_net, struct net_device *dev, static const struct nla_policy ppp_nl_policy[IFLA_PPP_MAX + 1] = { [IFLA_PPP_DEV_FD] = { .type = NLA_S32 }, + [IFLA_PPP_UNIT] = NLA_POLICY_MIN(NLA_S32, 0), }; static int ppp_nl_validate(struct nlattr *tb[], struct nlattr *data[],
@@ -1316,7 +1317,6 @@ static int ppp_nl_newlink(struct net_device *dev, struct nlattr **data = params->data; struct nlattr **tb = params->tb; struct ppp_config conf = { - .unit = -1, .ifname_is_set = true, }; struct file *file;
@@ -1342,6 +1342,7 @@ static int ppp_nl_newlink(struct net_device *dev, } conf.file = file; + conf.unit = nla_get_s32_default(data[IFLA_PPP_UNIT], -1); /* Don't use device name generated by the rtnetlink layer when ifname * isn't specified. Let ppp_dev_configure() set the device name using
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index e9b5f79e1ee1..40523cd01a8b 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h@@ -1477,6 +1477,7 @@ enum { enum { IFLA_PPP_UNSPEC, IFLA_PPP_DEV_FD, + IFLA_PPP_UNIT, __IFLA_PPP_MAX }; #define IFLA_PPP_MAX (__IFLA_PPP_MAX - 1)
diff --git a/tools/include/uapi/linux/if_link.h b/tools/include/uapi/linux/if_link.h
index 7e46ca4cd31b..150a582ae498 100644
--- a/tools/include/uapi/linux/if_link.h
+++ b/tools/include/uapi/linux/if_link.h@@ -1465,6 +1465,7 @@ enum { enum { IFLA_PPP_UNSPEC, IFLA_PPP_DEV_FD, + IFLA_PPP_UNIT, __IFLA_PPP_MAX }; #define IFLA_PPP_MAX (__IFLA_PPP_MAX - 1)
--
2.51.0