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netkit: Allow for configuring needed_{head,tail}room 

Allow the user to configure needed_{head,tail}room for both netkit
devices. The idea is similar to 163e529200 ("veth: implement
ndo_set_rx_headroom") with the difference that the two parameters
can be specified upon device creation. By default the current behavior
stays as is which is needed_{head,tail}room is 0.

In case of Cilium, for example, the netkit devices are not enslaved
into a bridge or openvswitch device (rather, BPF-based redirection
is used out of tcx), and as such these parameters are not propagated
into the Pod's netns via peer device.

Given Cilium can run in vxlan/geneve tunneling mode (needed_headroom)
and/or be used in combination with WireGuard (needed_{head,tail}room),
allow the Cilium CNI plugin to specify these two upon netkit device
creation.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/bpf/20241220234658.490686-1-daniel@iogearbox.net
This commit is contained in:
Daniel Borkmann 2024-12-21 00:46:56 +01:00
parent dad704ebe3
commit b9ed315d3c
3 changed files with 47 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

66
drivers/net/netkit.c
View File

@ -338,6 +338,7 @@ static int netkit_new_link(struct net *peer_net, struct net_device *dev,
enum netkit_scrub scrub_peer = NETKIT_SCRUB_DEFAULT;
enum netkit_mode mode = NETKIT_L3;
unsigned char ifname_assign_type;
u16 headroom = 0, tailroom = 0;
struct ifinfomsg *ifmp = NULL;
struct net_device *peer;
char ifname[IFNAMSIZ];
@ -371,6 +372,10 @@ static int netkit_new_link(struct net *peer_net, struct net_device *dev,
if (err < 0)
return err;
}
if (data[IFLA_NETKIT_HEADROOM])
headroom = nla_get_u16(data[IFLA_NETKIT_HEADROOM]);
if (data[IFLA_NETKIT_TAILROOM])
tailroom = nla_get_u16(data[IFLA_NETKIT_TAILROOM]);
}
if (ifmp && tbp[IFLA_IFNAME]) {
@ -390,6 +395,14 @@ static int netkit_new_link(struct net *peer_net, struct net_device *dev,
return PTR_ERR(peer);
netif_inherit_tso_max(peer, dev);
if (headroom) {
peer->needed_headroom = headroom;
dev->needed_headroom = headroom;
}
if (tailroom) {
peer->needed_tailroom = tailroom;
dev->needed_tailroom = tailroom;
}
if (mode == NETKIT_L2 && !(ifmp && tbp[IFLA_ADDRESS]))
eth_hw_addr_random(peer);
@ -401,6 +414,7 @@ static int netkit_new_link(struct net *peer_net, struct net_device *dev,
nk->policy = policy_peer;
nk->scrub = scrub_peer;
nk->mode = mode;
nk->headroom = headroom;
bpf_mprog_bundle_init(&nk->bundle);
err = register_netdevice(peer);
@ -426,6 +440,7 @@ static int netkit_new_link(struct net *peer_net, struct net_device *dev,
nk->policy = policy_prim;
nk->scrub = scrub_prim;
nk->mode = mode;
nk->headroom = headroom;
bpf_mprog_bundle_init(&nk->bundle);
err = register_netdevice(dev);
@ -850,7 +865,18 @@ static int netkit_change_link(struct net_device *dev, struct nlattr *tb[],
struct net_device *peer = rtnl_dereference(nk->peer);
enum netkit_action policy;
struct nlattr *attr;
int err;
int err, i;
static const struct {
u32 attr;
char *name;
} fixed_params[] = {
{ IFLA_NETKIT_MODE, "operating mode" },
{ IFLA_NETKIT_SCRUB, "scrubbing" },
{ IFLA_NETKIT_PEER_SCRUB, "peer scrubbing" },
{ IFLA_NETKIT_PEER_INFO, "peer info" },
{ IFLA_NETKIT_HEADROOM, "headroom" },
{ IFLA_NETKIT_TAILROOM, "tailroom" },
};
if (!nk->primary) {
NL_SET_ERR_MSG(extack,
@ -858,28 +884,14 @@ static int netkit_change_link(struct net_device *dev, struct nlattr *tb[],
return -EACCES;
}
if (data[IFLA_NETKIT_MODE]) {
NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_MODE],
"netkit link operating mode cannot be changed after device creation");
return -EACCES;
}
if (data[IFLA_NETKIT_SCRUB]) {
NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_SCRUB],
"netkit scrubbing cannot be changed after device creation");
return -EACCES;
}
if (data[IFLA_NETKIT_PEER_SCRUB]) {
NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_PEER_SCRUB],
"netkit scrubbing cannot be changed after device creation");
return -EACCES;
}
if (data[IFLA_NETKIT_PEER_INFO]) {
NL_SET_ERR_MSG_ATTR(extack, data[IFLA_NETKIT_PEER_INFO],
"netkit peer info cannot be changed after device creation");
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(fixed_params); i++) {
attr = data[fixed_params[i].attr];
if (attr) {
NL_SET_ERR_MSG_ATTR_FMT(extack, attr,
"netkit link %s cannot be changed after device creation",
fixed_params[i].name);
return -EACCES;
}
}
if (data[IFLA_NETKIT_POLICY]) {
@ -914,6 +926,8 @@ static size_t netkit_get_size(const struct net_device *dev)
nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_PEER_SCRUB */
nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_MODE */
nla_total_size(sizeof(u8)) + /* IFLA_NETKIT_PRIMARY */
nla_total_size(sizeof(u16)) + /* IFLA_NETKIT_HEADROOM */
nla_total_size(sizeof(u16)) + /* IFLA_NETKIT_TAILROOM */
0;
}
@ -930,6 +944,10 @@ static int netkit_fill_info(struct sk_buff *skb, const struct net_device *dev)
return -EMSGSIZE;
if (nla_put_u32(skb, IFLA_NETKIT_SCRUB, nk->scrub))
return -EMSGSIZE;
if (nla_put_u16(skb, IFLA_NETKIT_HEADROOM, dev->needed_headroom))
return -EMSGSIZE;
if (nla_put_u16(skb, IFLA_NETKIT_TAILROOM, dev->needed_tailroom))
return -EMSGSIZE;
if (peer) {
nk = netkit_priv(peer);
@ -947,6 +965,8 @@ static const struct nla_policy netkit_policy[IFLA_NETKIT_MAX + 1] = {
[IFLA_NETKIT_MODE] = NLA_POLICY_MAX(NLA_U32, NETKIT_L3),
[IFLA_NETKIT_POLICY] = { .type = NLA_U32 },
[IFLA_NETKIT_PEER_POLICY] = { .type = NLA_U32 },
[IFLA_NETKIT_HEADROOM] = { .type = NLA_U16 },
[IFLA_NETKIT_TAILROOM] = { .type = NLA_U16 },
[IFLA_NETKIT_SCRUB] = NLA_POLICY_MAX(NLA_U32, NETKIT_SCRUB_DEFAULT),
[IFLA_NETKIT_PEER_SCRUB] = NLA_POLICY_MAX(NLA_U32, NETKIT_SCRUB_DEFAULT),
[IFLA_NETKIT_PRIMARY] = { .type = NLA_REJECT,

2
include/uapi/linux/if_link.h
View File

@ -1315,6 +1315,8 @@ enum {
IFLA_NETKIT_MODE,
IFLA_NETKIT_SCRUB,
IFLA_NETKIT_PEER_SCRUB,
IFLA_NETKIT_HEADROOM,
IFLA_NETKIT_TAILROOM,
__IFLA_NETKIT_MAX,
};
#define IFLA_NETKIT_MAX (__IFLA_NETKIT_MAX - 1)

2
tools/include/uapi/linux/if_link.h
View File

@ -1315,6 +1315,8 @@ enum {
IFLA_NETKIT_MODE,
IFLA_NETKIT_SCRUB,
IFLA_NETKIT_PEER_SCRUB,
IFLA_NETKIT_HEADROOM,
IFLA_NETKIT_TAILROOM,
__IFLA_NETKIT_MAX,
};
#define IFLA_NETKIT_MAX (__IFLA_NETKIT_MAX - 1)