| Message ID | 2e761d23d591a9536eaa3ecd4be8d78c99f00964.1600967205.git.daniel@iogearbox.net |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [bpf-next,1/6] bpf: add classid helper only based on skb->sk | expand |
On Thu, 24 Sep 2020 20:21:22 +0200 Daniel Borkmann wrote: > Similarly to 5a52ae4e32a6 ("bpf: Allow to retrieve cgroup v1 classid > from v2 hooks"), add a helper to retrieve cgroup v1 classid solely > based on the skb->sk, so it can be used as key as part of BPF map > lookups out of tc from host ns, in particular given the skb->sk is > retained these days when crossing net ns thanks to 9c4c325252c5 > ("skbuff: preserve sock reference when scrubbing the skb."). This > is similar to bpf_skb_cgroup_id() which implements the same for v2. > Kubernetes ecosystem is still operating on v1 however, hence net_cls > needs to be used there until this can be dropped in with the v2 > helper of bpf_skb_cgroup_id(). > > Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> FWIW lot's of whitespace warnings from checkpatch --strict about comments having spaces before tabs here.
On 9/25/20 4:46 PM, Jakub Kicinski wrote: > On Thu, 24 Sep 2020 20:21:22 +0200 Daniel Borkmann wrote: >> Similarly to 5a52ae4e32a6 ("bpf: Allow to retrieve cgroup v1 classid >> from v2 hooks"), add a helper to retrieve cgroup v1 classid solely >> based on the skb->sk, so it can be used as key as part of BPF map >> lookups out of tc from host ns, in particular given the skb->sk is >> retained these days when crossing net ns thanks to 9c4c325252c5 >> ("skbuff: preserve sock reference when scrubbing the skb."). This >> is similar to bpf_skb_cgroup_id() which implements the same for v2. >> Kubernetes ecosystem is still operating on v1 however, hence net_cls >> needs to be used there until this can be dropped in with the v2 >> helper of bpf_skb_cgroup_id(). >> >> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> > > FWIW lot's of whitespace warnings from checkpatch --strict about > comments having spaces before tabs here. Expected given the way the UAPI helper comment is formatted / done in order to then render the man page. So it's formatted the same way as the other helper descriptions. Thanks, Daniel
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index a22812561064..48ecf246d047 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -3586,6 +3586,15 @@ union bpf_attr { * the data in *dst*. This is a wrapper of **copy_from_user**\ (). * Return * 0 on success, or a negative error in case of failure. + * + * u64 bpf_skb_cgroup_classid(struct sk_buff *skb) + * Description + * See **bpf_get_cgroup_classid**\ () for the main description. + * This helper differs from **bpf_get_cgroup_classid**\ () in that + * the cgroup v1 net_cls class is retrieved only from the *skb*'s + * associated socket instead of the current process. + * Return + * The id is returned or 0 in case the id could not be retrieved. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3737,6 +3746,7 @@ union bpf_attr { FN(inode_storage_delete), \ FN(d_path), \ FN(copy_from_user), \ + FN(skb_cgroup_classid), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/net/core/filter.c b/net/core/filter.c index 6014e5f40c58..0f913755bcba 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2704,6 +2704,23 @@ static const struct bpf_func_proto bpf_get_cgroup_classid_curr_proto = { .gpl_only = false, .ret_type = RET_INTEGER, }; + +BPF_CALL_1(bpf_skb_cgroup_classid, const struct sk_buff *, skb) +{ + struct sock *sk = skb_to_full_sk(skb); + + if (!sk || !sk_fullsock(sk)) + return 0; + + return sock_cgroup_classid(&sk->sk_cgrp_data); +} + +static const struct bpf_func_proto bpf_skb_cgroup_classid_proto = { + .func = bpf_skb_cgroup_classid, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, +}; #endif BPF_CALL_1(bpf_get_cgroup_classid, const struct sk_buff *, skb) @@ -6770,6 +6787,10 @@ tc_cls_act_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_skb_get_xfrm_state: return &bpf_skb_get_xfrm_state_proto; #endif +#ifdef CONFIG_CGROUP_NET_CLASSID + case BPF_FUNC_skb_cgroup_classid: + return &bpf_skb_cgroup_classid_proto; +#endif #ifdef CONFIG_SOCK_CGROUP_DATA case BPF_FUNC_skb_cgroup_id: return &bpf_skb_cgroup_id_proto; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index a22812561064..48ecf246d047 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -3586,6 +3586,15 @@ union bpf_attr { * the data in *dst*. This is a wrapper of **copy_from_user**\ (). * Return * 0 on success, or a negative error in case of failure. + * + * u64 bpf_skb_cgroup_classid(struct sk_buff *skb) + * Description + * See **bpf_get_cgroup_classid**\ () for the main description. + * This helper differs from **bpf_get_cgroup_classid**\ () in that + * the cgroup v1 net_cls class is retrieved only from the *skb*'s + * associated socket instead of the current process. + * Return + * The id is returned or 0 in case the id could not be retrieved. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -3737,6 +3746,7 @@ union bpf_attr { FN(inode_storage_delete), \ FN(d_path), \ FN(copy_from_user), \ + FN(skb_cgroup_classid), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper
Similarly to 5a52ae4e32a6 ("bpf: Allow to retrieve cgroup v1 classid from v2 hooks"), add a helper to retrieve cgroup v1 classid solely based on the skb->sk, so it can be used as key as part of BPF map lookups out of tc from host ns, in particular given the skb->sk is retained these days when crossing net ns thanks to 9c4c325252c5 ("skbuff: preserve sock reference when scrubbing the skb."). This is similar to bpf_skb_cgroup_id() which implements the same for v2. Kubernetes ecosystem is still operating on v1 however, hence net_cls needs to be used there until this can be dropped in with the v2 helper of bpf_skb_cgroup_id(). Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> --- include/uapi/linux/bpf.h | 10 ++++++++++ net/core/filter.c | 21 +++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 10 ++++++++++ 3 files changed, 41 insertions(+)