mirror of
https://github.com/xdp-project/bpf-examples.git
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0306ff7cca
The type of the net->net_cookie field member was changed in kernel 5.12
with commit 3d368ab87cf6 ("net: initialize net->net_cookie at netns setup").
Older versions of the kernel devices net->net_cookie as an atomic64_t
instead of a u64. This causes CO-RE reading of the field to fail due to the
type mismatch. Handle this by adding CO-RE checks for the old type as well
and using the CO-RE facility to check for the right type at load time.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
63 lines
1.5 KiB
C
63 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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#ifndef BPF_DEFS_H
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#define BPF_DEFS_H
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/* cookie for init ns; hoping this is stable */
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#define INIT_NS 1
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/* partial structs for reading bond parameters.
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*
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* These are deliberately *not* declared with the preserve_access_index, as
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* we'll read them with plan BPF_PROBE_READ() below; this is to make sure they
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* work even without module BTF, and the fields we need are only the first ones
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* of each struct which have been stable for a long time.
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*/
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struct slave {
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struct net_device *dev; /* first - useful for panic debug */
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};
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struct bonding {
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struct net_device *dev; /* first - useful for panic debug */
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struct slave *curr_active_slave;
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};
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/* local partial kernel struct definitions with just the members we need */
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struct net {
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__u64 net_cookie;
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} __attribute__((preserve_access_index));
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typedef struct {
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__s64 counter;
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} atomic64_t;
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struct net___old {
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atomic64_t net_cookie;
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} __attribute__((preserve_access_index));
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struct net_device {
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int ifindex;
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struct {
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struct net *net;
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} nd_net;
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} __attribute__((preserve_access_index));
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struct netdev_notifier_info {
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struct net_device *dev;
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} __attribute__((preserve_access_index));
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static inline __u64 read_net_cookie(struct net *net)
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{
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if (bpf_core_field_exists(net->net_cookie)) {
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return BPF_CORE_READ(net, net_cookie);
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} else {
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struct net___old *n_old = (void *)net;
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atomic64_t cookie_old;
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cookie_old = BPF_CORE_READ(n_old, net_cookie);
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return cookie_old.counter;
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}
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}
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#endif
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