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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-10 20:49:52 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-10 20:49:52 +0000 |
commit | 55944e5e40b1be2afc4855d8d2baf4b73d1876b5 (patch) | |
tree | 33f869f55a1b149e9b7c2b7e201867ca5dd52992 /src/core/bpf/restrict_ifaces/restrict-ifaces.bpf.c | |
parent | Initial commit. (diff) | |
download | systemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.tar.xz systemd-55944e5e40b1be2afc4855d8d2baf4b73d1876b5.zip |
Adding upstream version 255.4.upstream/255.4
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/core/bpf/restrict_ifaces/restrict-ifaces.bpf.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/src/core/bpf/restrict_ifaces/restrict-ifaces.bpf.c b/src/core/bpf/restrict_ifaces/restrict-ifaces.bpf.c new file mode 100644 index 0000000..32cde5c --- /dev/null +++ b/src/core/bpf/restrict_ifaces/restrict-ifaces.bpf.c @@ -0,0 +1,52 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +/* <linux/bpf.h> must precede <bpf/bpf_helpers.h> due to integer types + * in bpf helpers signatures. + */ +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> + +const volatile __u8 is_allow_list = 0; + +/* Map containing the network interfaces indexes. + * The interpretation of the map depends on the value of is_allow_list. + */ +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __type(key, __u32); + __type(value, __u8); +} sd_restrictif SEC(".maps"); + +#define DROP 0 +#define PASS 1 + +static __always_inline int restrict_network_interfaces_impl(const struct __sk_buff *sk) { + __u32 zero = 0, ifindex; + __u8 *lookup_result; + + ifindex = sk->ifindex; + lookup_result = bpf_map_lookup_elem(&sd_restrictif, &ifindex); + if (is_allow_list) { + /* allow-list: let the packet pass if iface in the list */ + if (lookup_result) + return PASS; + } else { + /* deny-list: let the packet pass if iface *not* in the list */ + if (!lookup_result) + return PASS; + } + + return DROP; +} + +SEC("cgroup_skb/egress") +int sd_restrictif_e(const struct __sk_buff *sk) { + return restrict_network_interfaces_impl(sk); +} + +SEC("cgroup_skb/ingress") +int sd_restrictif_i(const struct __sk_buff *sk) { + return restrict_network_interfaces_impl(sk); +} + +static const char _license[] SEC("license") = "LGPL-2.1-or-later"; |