forked from luck/tmp_suning_uos_patched
6102365876
Add new cgroup based program type, BPF_PROG_TYPE_CGROUP_SOCK. Similar to BPF_PROG_TYPE_CGROUP_SKB programs can be attached to a cgroup and run any time a process in the cgroup opens an AF_INET or AF_INET6 socket. Currently only sk_bound_dev_if is exported to userspace for modification by a bpf program. This allows a cgroup to be configured such that AF_INET{6} sockets opened by processes are automatically bound to a specific device. In turn, this enables the running of programs that do not support SO_BINDTODEVICE in a specific VRF context / L3 domain. Signed-off-by: David Ahern <dsa@cumulusnetworks.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
201 lines
5.6 KiB
C
201 lines
5.6 KiB
C
/*
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* Functions to manage eBPF programs attached to cgroups
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*
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* Copyright (c) 2016 Daniel Mack
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*
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* This file is subject to the terms and conditions of version 2 of the GNU
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* General Public License. See the file COPYING in the main directory of the
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* Linux distribution for more details.
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*/
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#include <linux/kernel.h>
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#include <linux/atomic.h>
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#include <linux/cgroup.h>
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#include <linux/slab.h>
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#include <linux/bpf.h>
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#include <linux/bpf-cgroup.h>
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#include <net/sock.h>
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DEFINE_STATIC_KEY_FALSE(cgroup_bpf_enabled_key);
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EXPORT_SYMBOL(cgroup_bpf_enabled_key);
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/**
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* cgroup_bpf_put() - put references of all bpf programs
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* @cgrp: the cgroup to modify
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*/
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void cgroup_bpf_put(struct cgroup *cgrp)
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{
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unsigned int type;
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for (type = 0; type < ARRAY_SIZE(cgrp->bpf.prog); type++) {
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struct bpf_prog *prog = cgrp->bpf.prog[type];
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if (prog) {
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bpf_prog_put(prog);
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static_branch_dec(&cgroup_bpf_enabled_key);
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}
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}
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}
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/**
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* cgroup_bpf_inherit() - inherit effective programs from parent
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* @cgrp: the cgroup to modify
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* @parent: the parent to inherit from
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*/
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void cgroup_bpf_inherit(struct cgroup *cgrp, struct cgroup *parent)
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{
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unsigned int type;
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for (type = 0; type < ARRAY_SIZE(cgrp->bpf.effective); type++) {
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struct bpf_prog *e;
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e = rcu_dereference_protected(parent->bpf.effective[type],
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lockdep_is_held(&cgroup_mutex));
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rcu_assign_pointer(cgrp->bpf.effective[type], e);
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}
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}
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/**
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* __cgroup_bpf_update() - Update the pinned program of a cgroup, and
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* propagate the change to descendants
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* @cgrp: The cgroup which descendants to traverse
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* @parent: The parent of @cgrp, or %NULL if @cgrp is the root
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* @prog: A new program to pin
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* @type: Type of pinning operation (ingress/egress)
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*
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* Each cgroup has a set of two pointers for bpf programs; one for eBPF
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* programs it owns, and which is effective for execution.
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*
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* If @prog is not %NULL, this function attaches a new program to the cgroup
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* and releases the one that is currently attached, if any. @prog is then made
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* the effective program of type @type in that cgroup.
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*
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* If @prog is %NULL, the currently attached program of type @type is released,
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* and the effective program of the parent cgroup (if any) is inherited to
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* @cgrp.
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*
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* Then, the descendants of @cgrp are walked and the effective program for
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* each of them is set to the effective program of @cgrp unless the
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* descendant has its own program attached, in which case the subbranch is
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* skipped. This ensures that delegated subcgroups with own programs are left
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* untouched.
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*
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* Must be called with cgroup_mutex held.
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*/
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void __cgroup_bpf_update(struct cgroup *cgrp,
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struct cgroup *parent,
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struct bpf_prog *prog,
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enum bpf_attach_type type)
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{
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struct bpf_prog *old_prog, *effective;
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struct cgroup_subsys_state *pos;
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old_prog = xchg(cgrp->bpf.prog + type, prog);
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effective = (!prog && parent) ?
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rcu_dereference_protected(parent->bpf.effective[type],
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lockdep_is_held(&cgroup_mutex)) :
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prog;
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css_for_each_descendant_pre(pos, &cgrp->self) {
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struct cgroup *desc = container_of(pos, struct cgroup, self);
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/* skip the subtree if the descendant has its own program */
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if (desc->bpf.prog[type] && desc != cgrp)
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pos = css_rightmost_descendant(pos);
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else
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rcu_assign_pointer(desc->bpf.effective[type],
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effective);
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}
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if (prog)
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static_branch_inc(&cgroup_bpf_enabled_key);
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if (old_prog) {
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bpf_prog_put(old_prog);
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static_branch_dec(&cgroup_bpf_enabled_key);
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}
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}
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/**
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* __cgroup_bpf_run_filter_skb() - Run a program for packet filtering
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* @sk: The socken sending or receiving traffic
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* @skb: The skb that is being sent or received
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* @type: The type of program to be exectuted
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*
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* If no socket is passed, or the socket is not of type INET or INET6,
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* this function does nothing and returns 0.
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*
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* The program type passed in via @type must be suitable for network
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* filtering. No further check is performed to assert that.
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*
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* This function will return %-EPERM if any if an attached program was found
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* and if it returned != 1 during execution. In all other cases, 0 is returned.
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*/
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int __cgroup_bpf_run_filter_skb(struct sock *sk,
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struct sk_buff *skb,
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enum bpf_attach_type type)
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{
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struct bpf_prog *prog;
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struct cgroup *cgrp;
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int ret = 0;
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if (!sk || !sk_fullsock(sk))
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return 0;
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if (sk->sk_family != AF_INET &&
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sk->sk_family != AF_INET6)
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return 0;
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cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
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rcu_read_lock();
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prog = rcu_dereference(cgrp->bpf.effective[type]);
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if (prog) {
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unsigned int offset = skb->data - skb_network_header(skb);
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__skb_push(skb, offset);
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ret = bpf_prog_run_save_cb(prog, skb) == 1 ? 0 : -EPERM;
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__skb_pull(skb, offset);
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}
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rcu_read_unlock();
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return ret;
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}
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EXPORT_SYMBOL(__cgroup_bpf_run_filter_skb);
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/**
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* __cgroup_bpf_run_filter_sk() - Run a program on a sock
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* @sk: sock structure to manipulate
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* @type: The type of program to be exectuted
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*
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* socket is passed is expected to be of type INET or INET6.
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*
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* The program type passed in via @type must be suitable for sock
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* filtering. No further check is performed to assert that.
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*
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* This function will return %-EPERM if any if an attached program was found
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* and if it returned != 1 during execution. In all other cases, 0 is returned.
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*/
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int __cgroup_bpf_run_filter_sk(struct sock *sk,
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enum bpf_attach_type type)
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{
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struct cgroup *cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
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struct bpf_prog *prog;
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int ret = 0;
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rcu_read_lock();
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prog = rcu_dereference(cgrp->bpf.effective[type]);
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if (prog)
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ret = BPF_PROG_RUN(prog, sk) == 1 ? 0 : -EPERM;
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rcu_read_unlock();
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return ret;
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}
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EXPORT_SYMBOL(__cgroup_bpf_run_filter_sk);
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