--- /dev/null
+/***
+ This file is part of systemd.
+
+ Copyright 2016 Daniel Mack
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <arpa/inet.h>
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/libbpf.h>
+#include <net/ethernet.h>
+#include <net/if.h>
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "bpf-firewall.h"
+#include "bpf-program.h"
+#include "fd-util.h"
+#include "ip-address-access.h"
+#include "unit.h"
+
+enum {
+ MAP_KEY_PACKETS,
+ MAP_KEY_BYTES,
+};
+
+enum {
+ ACCESS_ALLOWED = 1,
+ ACCESS_DENIED = 2,
+};
+
+/* Compile instructions for one list of addresses, one direction and one specific verdict on matches. */
+
+static int add_lookup_instructions(
+ BPFProgram *p,
+ int map_fd,
+ int protocol,
+ bool is_ingress,
+ int verdict) {
+
+ int r, addr_offset, addr_size;
+
+ assert(p);
+ assert(map_fd >= 0);
+
+ switch (protocol) {
+
+ case ETH_P_IP:
+ addr_size = sizeof(uint32_t);
+ addr_offset = is_ingress ?
+ offsetof(struct iphdr, saddr) :
+ offsetof(struct iphdr, daddr);
+ break;
+
+ case ETH_P_IPV6:
+ addr_size = 4 * sizeof(uint32_t);
+ addr_offset = is_ingress ?
+ offsetof(struct ip6_hdr, ip6_src.s6_addr) :
+ offsetof(struct ip6_hdr, ip6_dst.s6_addr);
+ break;
+
+ default:
+ return -EAFNOSUPPORT;
+ }
+
+ do {
+ /* Compare IPv4 with one word instruction (32bit) */
+ struct bpf_insn insn[] = {
+ /* If skb->protocol != ETH_P_IP, skip this whole block. The offset will be set later. */
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_7, htobe16(protocol), 0),
+
+ /*
+ * Call into BPF_FUNC_skb_load_bytes to load the dst/src IP address
+ *
+ * R1: Pointer to the skb
+ * R2: Data offset
+ * R3: Destination buffer on the stack (r10 - 4)
+ * R4: Number of bytes to read (4)
+ */
+
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+ BPF_MOV32_IMM(BPF_REG_2, addr_offset),
+
+ BPF_MOV64_REG(BPF_REG_3, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, -addr_size),
+
+ BPF_MOV32_IMM(BPF_REG_4, addr_size),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_skb_load_bytes),
+
+ /*
+ * Call into BPF_FUNC_map_lookup_elem to see if the address matches any entry in the
+ * LPM trie map. For this to work, the prefixlen field of 'struct bpf_lpm_trie_key'
+ * has to be set to the maximum possible value.
+ *
+ * On success, the looked up value is stored in R0. For this application, the actual
+ * value doesn't matter, however; we just set the bit in @verdict in R8 if we found any
+ * matching value.
+ */
+
+ BPF_LD_MAP_FD(BPF_REG_1, map_fd),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -addr_size - sizeof(uint32_t)),
+ BPF_ST_MEM(BPF_W, BPF_REG_2, 0, addr_size * 8),
+
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
+ BPF_ALU32_IMM(BPF_OR, BPF_REG_8, verdict),
+ };
+
+ /* Jump label fixup */
+ insn[0].off = ELEMENTSOF(insn) - 1;
+
+ r = bpf_program_add_instructions(p, insn, ELEMENTSOF(insn));
+ if (r < 0)
+ return r;
+
+ } while (false);
+
+ return 0;
+}
+
+static int bpf_firewall_compile_bpf(
+ Unit *u,
+ bool is_ingress,
+ BPFProgram **ret) {
+
+ struct bpf_insn pre_insn[] = {
+ /*
+ * When the eBPF program is entered, R1 contains the address of the skb.
+ * However, R1-R5 are scratch registers that are not preserved when calling
+ * into kernel functions, so we need to save anything that's supposed to
+ * stay around to R6-R9. Save the skb to R6.
+ */
+ BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+
+ /*
+ * Although we cannot access the skb data directly from eBPF programs used in this
+ * scenario, the kernel has prepared some fields for us to access through struct __sk_buff.
+ * Load the protocol (IPv4, IPv6) used by the packet in flight once and cache it in R7
+ * for later use.
+ */
+ BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6, offsetof(struct __sk_buff, protocol)),
+
+ /*
+ * R8 is used to keep track of whether any address check has explicitly allowed or denied the packet
+ * through ACCESS_DENIED or ACCESS_ALLOWED bits. Reset them both to 0 in the beginning.
+ */
+ BPF_MOV32_IMM(BPF_REG_8, 0),
+ };
+
+ /*
+ * The access checkers compiled for the configured allowance and denial lists
+ * write to R8 at runtime. The following code prepares for an early exit that
+ * skip the accounting if the packet is denied.
+ *
+ * R0 = 1
+ * if (R8 == ACCESS_DENIED)
+ * R0 = 0
+ *
+ * This means that if both ACCESS_DENIED and ACCESS_ALLOWED are set, the packet
+ * is allowed to pass.
+ */
+ struct bpf_insn post_insn[] = {
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_8, ACCESS_DENIED, 1),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ };
+
+ _cleanup_(bpf_program_unrefp) BPFProgram *p = NULL;
+ int accounting_map_fd, r;
+ bool access_enabled;
+
+ assert(u);
+ assert(ret);
+
+ accounting_map_fd = is_ingress ?
+ u->ip_accounting_ingress_map_fd :
+ u->ip_accounting_egress_map_fd;
+
+ access_enabled =
+ u->ipv4_allow_map_fd >= 0 ||
+ u->ipv6_allow_map_fd >= 0 ||
+ u->ipv4_deny_map_fd >= 0 ||
+ u->ipv6_deny_map_fd >= 0;
+
+ if (accounting_map_fd < 0 && !access_enabled) {
+ *ret = NULL;
+ return 0;
+ }
+
+ r = bpf_program_new(BPF_PROG_TYPE_CGROUP_SKB, &p);
+ if (r < 0)
+ return r;
+
+ r = bpf_program_add_instructions(p, pre_insn, ELEMENTSOF(pre_insn));
+ if (r < 0)
+ return r;
+
+ if (access_enabled) {
+ /*
+ * The simple rule this function translates into eBPF instructions is:
+ *
+ * - Access will be granted when an address matches an entry in @list_allow
+ * - Otherwise, access will be denied when an address matches an entry in @list_deny
+ * - Otherwise, access will be granted
+ */
+
+ if (u->ipv4_deny_map_fd >= 0) {
+ r = add_lookup_instructions(p, u->ipv4_deny_map_fd, ETH_P_IP, is_ingress, ACCESS_DENIED);
+ if (r < 0)
+ return r;
+ }
+
+ if (u->ipv6_deny_map_fd >= 0) {
+ r = add_lookup_instructions(p, u->ipv6_deny_map_fd, ETH_P_IPV6, is_ingress, ACCESS_DENIED);
+ if (r < 0)
+ return r;
+ }
+
+ if (u->ipv4_allow_map_fd >= 0) {
+ r = add_lookup_instructions(p, u->ipv4_allow_map_fd, ETH_P_IP, is_ingress, ACCESS_ALLOWED);
+ if (r < 0)
+ return r;
+ }
+
+ if (u->ipv6_allow_map_fd >= 0) {
+ r = add_lookup_instructions(p, u->ipv6_allow_map_fd, ETH_P_IPV6, is_ingress, ACCESS_ALLOWED);
+ if (r < 0)
+ return r;
+ }
+ }
+
+ r = bpf_program_add_instructions(p, post_insn, ELEMENTSOF(post_insn));
+ if (r < 0)
+ return r;
+
+ if (accounting_map_fd >= 0) {
+ struct bpf_insn insn[] = {
+ /*
+ * If R0 == 0, the packet will be denied; skip the accounting instructions in this case.
+ * The jump label will be fixed up later.
+ */
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 0),
+
+ /* Count packets */
+ BPF_MOV64_IMM(BPF_REG_0, MAP_KEY_PACKETS), /* r0 = 0 */
+ BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r2 = fp - 4 */
+ BPF_LD_MAP_FD(BPF_REG_1, accounting_map_fd), /* load map fd to r1 */
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
+ BPF_MOV64_IMM(BPF_REG_1, 1), /* r1 = 1 */
+ BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */
+
+ /* Count bytes */
+ BPF_MOV64_IMM(BPF_REG_0, MAP_KEY_BYTES), /* r0 = 1 */
+ BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4), /* *(u32 *)(fp - 4) = r0 */
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), /* r2 = fp - 4 */
+ BPF_LD_MAP_FD(BPF_REG_1, accounting_map_fd),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
+ BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_6, offsetof(struct __sk_buff, len)), /* r1 = skb->len */
+ BPF_RAW_INSN(BPF_STX | BPF_XADD | BPF_DW, BPF_REG_0, BPF_REG_1, 0, 0), /* xadd r0 += r1 */
+
+ /* Allow the packet to pass */
+ BPF_MOV64_IMM(BPF_REG_0, 1),
+ };
+
+ /* Jump label fixup */
+ insn[0].off = ELEMENTSOF(insn) - 1;
+
+ r = bpf_program_add_instructions(p, insn, ELEMENTSOF(insn));
+ if (r < 0)
+ return r;
+ }
+
+ do {
+ /*
+ * Exit from the eBPF program, R0 contains the verdict.
+ * 0 means the packet is denied, 1 means the packet may pass.
+ */
+ struct bpf_insn insn[] = {
+ BPF_EXIT_INSN()
+ };
+
+ r = bpf_program_add_instructions(p, insn, ELEMENTSOF(insn));
+ if (r < 0)
+ return r;
+ } while (false);
+
+ *ret = p;
+ p = NULL;
+
+ return 0;
+}
+
+static int bpf_firewall_count_access_items(IPAddressAccessItem *list, size_t *n_ipv4, size_t *n_ipv6) {
+ IPAddressAccessItem *a;
+
+ assert(n_ipv4);
+ assert(n_ipv6);
+
+ LIST_FOREACH(items, a, list) {
+ switch (a->family) {
+
+ case AF_INET:
+ (*n_ipv4)++;
+ break;
+
+ case AF_INET6:
+ (*n_ipv6)++;
+ break;
+
+ default:
+ return -EAFNOSUPPORT;
+ }
+ }
+
+ return 0;
+}
+
+static int bpf_firewall_add_access_items(
+ IPAddressAccessItem *list,
+ int ipv4_map_fd,
+ int ipv6_map_fd,
+ int verdict) {
+
+ struct bpf_lpm_trie_key *key_ipv4, *key_ipv6;
+ uint64_t value = verdict;
+ IPAddressAccessItem *a;
+ int r;
+
+ key_ipv4 = alloca0(offsetof(struct bpf_lpm_trie_key, data) + sizeof(uint32_t));
+ key_ipv6 = alloca0(offsetof(struct bpf_lpm_trie_key, data) + sizeof(uint32_t) * 4);
+
+ LIST_FOREACH(items, a, list) {
+ switch (a->family) {
+
+ case AF_INET:
+ key_ipv4->prefixlen = a->prefixlen;
+ memcpy(key_ipv4->data, &a->address, sizeof(uint32_t));
+
+ r = bpf_map_update_element(ipv4_map_fd, key_ipv4, &value);
+ if (r < 0)
+ return r;
+
+ break;
+
+ case AF_INET6:
+ key_ipv6->prefixlen = a->prefixlen;
+ memcpy(key_ipv6->data, &a->address, 4 * sizeof(uint32_t));
+
+ r = bpf_map_update_element(ipv6_map_fd, key_ipv6, &value);
+ if (r < 0)
+ return r;
+
+ break;
+
+ default:
+ return -EAFNOSUPPORT;
+ }
+ }
+
+ return 0;
+}
+
+static int bpf_firewall_prepare_access_maps(
+ Unit *u,
+ int verdict,
+ int *ret_ipv4_map_fd,
+ int *ret_ipv6_map_fd) {
+
+ _cleanup_close_ int ipv4_map_fd = -1, ipv6_map_fd = -1;
+ size_t n_ipv4 = 0, n_ipv6 = 0;
+ Unit *p;
+ int r;
+
+ assert(ret_ipv4_map_fd);
+ assert(ret_ipv6_map_fd);
+
+ for (p = u; p; p = UNIT_DEREF(p->slice)) {
+ CGroupContext *cc;
+
+ cc = unit_get_cgroup_context(p);
+ if (!cc)
+ continue;
+
+ bpf_firewall_count_access_items(verdict == ACCESS_ALLOWED ? cc->ip_address_allow : cc->ip_address_deny, &n_ipv4, &n_ipv6);
+ }
+
+ if (n_ipv4 > 0) {
+ ipv4_map_fd = bpf_map_new(
+ BPF_MAP_TYPE_LPM_TRIE,
+ offsetof(struct bpf_lpm_trie_key, data) + sizeof(uint32_t),
+ sizeof(uint64_t),
+ n_ipv4,
+ BPF_F_NO_PREALLOC);
+ if (ipv4_map_fd < 0)
+ return ipv4_map_fd;
+ }
+
+ if (n_ipv6 > 0) {
+ ipv6_map_fd = bpf_map_new(
+ BPF_MAP_TYPE_LPM_TRIE,
+ offsetof(struct bpf_lpm_trie_key, data) + sizeof(uint32_t)*4,
+ sizeof(uint64_t),
+ n_ipv6,
+ BPF_F_NO_PREALLOC);
+ if (ipv6_map_fd < 0)
+ return ipv6_map_fd;
+ }
+
+ for (p = u; p; p = UNIT_DEREF(p->slice)) {
+ CGroupContext *cc;
+
+ cc = unit_get_cgroup_context(p);
+ if (!cc)
+ continue;
+
+ r = bpf_firewall_add_access_items(verdict == ACCESS_ALLOWED ? cc->ip_address_allow : cc->ip_address_deny,
+ ipv4_map_fd, ipv6_map_fd, verdict);
+ if (r < 0)
+ return r;
+ }
+
+ *ret_ipv4_map_fd = ipv4_map_fd;
+ *ret_ipv6_map_fd = ipv6_map_fd;
+
+ ipv4_map_fd = ipv6_map_fd = -1;
+ return 0;
+}
+
+static int bpf_firewall_prepare_accounting_maps(bool enabled, int *fd_ingress, int *fd_egress) {
+ int r;
+
+ assert(fd_ingress);
+ assert(fd_egress);
+
+ if (enabled) {
+ if (*fd_ingress < 0) {
+ r = bpf_map_new(BPF_MAP_TYPE_ARRAY, sizeof(int), sizeof(uint64_t), 2, 0);
+ if (r < 0)
+ return r;
+
+ *fd_ingress = r;
+ }
+
+ if (*fd_egress < 0) {
+
+ r = bpf_map_new(BPF_MAP_TYPE_ARRAY, sizeof(int), sizeof(uint64_t), 2, 0);
+ if (r < 0)
+ return r;
+
+ *fd_egress = r;
+ }
+ } else {
+ *fd_ingress = safe_close(*fd_ingress);
+ *fd_egress = safe_close(*fd_egress);
+ }
+
+ return 0;
+}
+
+int bpf_firewall_compile(Unit *u) {
+ CGroupContext *cc;
+ int r;
+
+ assert(u);
+
+ r = bpf_firewall_supported();
+ if (r < 0)
+ return r;
+ if (r == 0) {
+ log_debug("BPF firewalling not supported on this systemd, proceeding without.");
+ return -EOPNOTSUPP;
+ }
+
+ /* Note that when we compile a new firewall we first flush out the access maps and the BPF programs themselves,
+ * but we reuse the the accounting maps. That way the firewall in effect always maps to the actual
+ * configuration, but we don't flush out the accounting unnecessarily */
+
+ u->ip_bpf_ingress = bpf_program_unref(u->ip_bpf_ingress);
+ u->ip_bpf_egress = bpf_program_unref(u->ip_bpf_egress);
+
+ u->ipv4_allow_map_fd = safe_close(u->ipv4_allow_map_fd);
+ u->ipv4_deny_map_fd = safe_close(u->ipv4_deny_map_fd);
+
+ u->ipv6_allow_map_fd = safe_close(u->ipv6_allow_map_fd);
+ u->ipv6_deny_map_fd = safe_close(u->ipv6_deny_map_fd);
+
+ cc = unit_get_cgroup_context(u);
+ if (!cc)
+ return -EINVAL;
+
+ r = bpf_firewall_prepare_access_maps(u, ACCESS_ALLOWED, &u->ipv4_allow_map_fd, &u->ipv6_allow_map_fd);
+ if (r < 0)
+ return log_error_errno(r, "Preparation of eBPF allow maps failed: %m");
+
+ r = bpf_firewall_prepare_access_maps(u, ACCESS_DENIED, &u->ipv4_deny_map_fd, &u->ipv6_deny_map_fd);
+ if (r < 0)
+ return log_error_errno(r, "Preparation of eBPF deny maps failed: %m");
+
+ r = bpf_firewall_prepare_accounting_maps(cc->ip_accounting, &u->ip_accounting_ingress_map_fd, &u->ip_accounting_egress_map_fd);
+ if (r < 0)
+ return log_error_errno(r, "Preparation of eBPF accounting maps failed: %m");
+
+ r = bpf_firewall_compile_bpf(u, true, &u->ip_bpf_ingress);
+ if (r < 0)
+ return log_error_errno(r, "Compilation for ingress BPF program failed: %m");
+
+ r = bpf_firewall_compile_bpf(u, false, &u->ip_bpf_egress);
+ if (r < 0)
+ return log_error_errno(r, "Compilation for egress BPF program failed: %m");
+
+ return 0;
+}
+
+int bpf_firewall_install(Unit *u) {
+ _cleanup_free_ char *path = NULL;
+ int r;
+
+ assert(u);
+
+ r = bpf_firewall_supported();
+ if (r < 0)
+ return r;
+ if (r == 0) {
+ log_debug("BPF firewalling not supported on this systemd, proceeding without.");
+ return -EOPNOTSUPP;
+ }
+
+ r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, NULL, &path);
+ if (r < 0)
+ return log_error_errno(r, "Failed to determine cgroup path: %m");
+
+ if (u->ip_bpf_egress) {
+ r = bpf_program_load_kernel(u->ip_bpf_egress, NULL, 0);
+ if (r < 0)
+ return log_error_errno(r, "Kernel upload of egress BPF program failed: %m");
+
+ r = bpf_program_cgroup_attach(u->ip_bpf_egress, BPF_CGROUP_INET_EGRESS, path);
+ if (r < 0)
+ return log_error_errno(r, "Attaching egress BPF program to cgroup %s failed: %m", path);
+ } else {
+ r = bpf_program_cgroup_detach(BPF_CGROUP_INET_EGRESS, path);
+ if (r < 0)
+ return log_full_errno(r == -ENOENT ? LOG_DEBUG : LOG_ERR, r,
+ "Detaching egress BPF program from cgroup failed: %m");
+ }
+
+ if (u->ip_bpf_ingress) {
+ r = bpf_program_load_kernel(u->ip_bpf_ingress, NULL, 0);
+ if (r < 0)
+ return log_error_errno(r, "Kernel upload of ingress BPF program failed: %m");
+
+ r = bpf_program_cgroup_attach(u->ip_bpf_ingress, BPF_CGROUP_INET_INGRESS, path);
+ if (r < 0)
+ return log_error_errno(r, "Attaching ingress BPF program to cgroup %s failed: %m", path);
+ } else {
+ r = bpf_program_cgroup_detach(BPF_CGROUP_INET_INGRESS, path);
+ if (r < 0)
+ return log_full_errno(r == -ENOENT ? LOG_DEBUG : LOG_ERR, r,
+ "Detaching ingress BPF program from cgroup failed: %m");
+ }
+
+ return 0;
+}
+
+int bpf_firewall_read_accounting(int map_fd, uint64_t *ret_bytes, uint64_t *ret_packets) {
+ uint64_t key, packets;
+ int r;
+
+ if (map_fd < 0)
+ return -EBADF;
+
+ if (ret_packets) {
+ key = MAP_KEY_PACKETS;
+ r = bpf_map_lookup_element(map_fd, &key, &packets);
+ if (r < 0)
+ return r;
+ }
+
+ if (ret_bytes) {
+ key = MAP_KEY_BYTES;
+ r = bpf_map_lookup_element(map_fd, &key, ret_bytes);
+ if (r < 0)
+ return r;
+ }
+
+ if (ret_packets)
+ *ret_packets = packets;
+
+ return 0;
+}
+
+int bpf_firewall_reset_accounting(int map_fd) {
+ uint64_t key, value = 0;
+ int r;
+
+ if (map_fd < 0)
+ return -EBADF;
+
+ key = MAP_KEY_PACKETS;
+ r = bpf_map_update_element(map_fd, &key, &value);
+ if (r < 0)
+ return r;
+
+ key = MAP_KEY_BYTES;
+ return bpf_map_update_element(map_fd, &key, &value);
+}
+
+
+int bpf_firewall_supported(void) {
+ static int supported = -1;
+ int fd, r;
+
+ /* Checks whether BPF firewalling is supported. For this, we check three things:
+ *
+ * a) whether we are privileged
+ * b) whether the unified hierarchy is being used
+ * c) the BPF implementation in the kernel supports BPF LPM TRIE maps, which we require
+ *
+ */
+
+ if (supported >= 0)
+ return supported;
+
+ if (geteuid() != 0)
+ return supported = false;
+
+ r = cg_unified_controller(SYSTEMD_CGROUP_CONTROLLER);
+ if (r < 0)
+ return log_error_errno(r, "Can't determine whether the unified hierarchy is used: %m");
+ if (r == 0)
+ return supported = false;
+
+ fd = bpf_map_new(BPF_MAP_TYPE_LPM_TRIE,
+ offsetof(struct bpf_lpm_trie_key, data) + sizeof(uint64_t),
+ sizeof(uint64_t),
+ 1,
+ BPF_F_NO_PREALLOC);
+ if (fd < 0) {
+ log_debug_errno(r, "Can't allocate BPF LPM TRIE map, BPF firewalling is not supported: %m");
+ return supported = false;
+ }
+
+ safe_close(fd);
+
+ return supported = true;
+}
projects / thirdparty / systemd.git / commitdiff
