| /* SPDX-License-Identifier: LGPL-2.1+ */ |
| /*** |
| This file is part of systemd. |
| |
| Copyright 2010 Lennart Poettering |
| |
| 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 <net/if.h> |
| #include <stdlib.h> |
| |
| #include "sd-netlink.h" |
| |
| #include "loopback-setup.h" |
| #include "missing.h" |
| #include "netlink-util.h" |
| |
| #define LOOPBACK_SETUP_TIMEOUT_USEC (5 * USEC_PER_SEC) |
| |
| struct state { |
| unsigned n_messages; |
| int rcode; |
| const char *error_message; |
| const char *success_message; |
| }; |
| |
| static int generic_handler(sd_netlink *rtnl, sd_netlink_message *m, void *userdata) { |
| struct state *s = userdata; |
| int r; |
| |
| assert(s); |
| assert(s->n_messages > 0); |
| s->n_messages--; |
| |
| errno = 0; |
| |
| r = sd_netlink_message_get_errno(m); |
| if (r < 0) |
| log_debug_errno(r, "%s: %m", s->error_message); |
| else |
| log_debug("%s", s->success_message); |
| |
| s->rcode = r; |
| return 0; |
| } |
| |
| static int start_loopback(sd_netlink *rtnl, struct state *s) { |
| _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL; |
| int r; |
| |
| assert(rtnl); |
| assert(s); |
| |
| r = sd_rtnl_message_new_link(rtnl, &req, RTM_SETLINK, LOOPBACK_IFINDEX); |
| if (r < 0) |
| return r; |
| |
| r = sd_rtnl_message_link_set_flags(req, IFF_UP, IFF_UP); |
| if (r < 0) |
| return r; |
| |
| r = sd_netlink_call_async(rtnl, req, generic_handler, s, LOOPBACK_SETUP_TIMEOUT_USEC, NULL); |
| if (r < 0) |
| return r; |
| |
| s->n_messages ++; |
| return 0; |
| } |
| |
| static int add_ipv4_address(sd_netlink *rtnl, struct state *s) { |
| _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL; |
| int r; |
| |
| assert(rtnl); |
| assert(s); |
| |
| r = sd_rtnl_message_new_addr(rtnl, &req, RTM_NEWADDR, LOOPBACK_IFINDEX, AF_INET); |
| if (r < 0) |
| return r; |
| |
| r = sd_rtnl_message_addr_set_prefixlen(req, 8); |
| if (r < 0) |
| return r; |
| |
| r = sd_rtnl_message_addr_set_flags(req, IFA_F_PERMANENT); |
| if (r < 0) |
| return r; |
| |
| r = sd_rtnl_message_addr_set_scope(req, RT_SCOPE_HOST); |
| if (r < 0) |
| return r; |
| |
| r = sd_netlink_message_append_in_addr(req, IFA_LOCAL, &(struct in_addr) { .s_addr = htobe32(INADDR_LOOPBACK) } ); |
| if (r < 0) |
| return r; |
| |
| r = sd_netlink_call_async(rtnl, req, generic_handler, s, USEC_INFINITY, NULL); |
| if (r < 0) |
| return r; |
| |
| s->n_messages ++; |
| return 0; |
| } |
| |
| static int add_ipv6_address(sd_netlink *rtnl, struct state *s) { |
| _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL; |
| int r; |
| |
| assert(rtnl); |
| assert(s); |
| |
| r = sd_rtnl_message_new_addr(rtnl, &req, RTM_NEWADDR, LOOPBACK_IFINDEX, AF_INET6); |
| if (r < 0) |
| return r; |
| |
| r = sd_rtnl_message_addr_set_prefixlen(req, 128); |
| if (r < 0) |
| return r; |
| |
| r = sd_rtnl_message_addr_set_flags(req, IFA_F_PERMANENT); |
| if (r < 0) |
| return r; |
| |
| r = sd_rtnl_message_addr_set_scope(req, RT_SCOPE_HOST); |
| if (r < 0) |
| return r; |
| |
| r = sd_netlink_message_append_in6_addr(req, IFA_LOCAL, &in6addr_loopback); |
| if (r < 0) |
| return r; |
| |
| r = sd_netlink_call_async(rtnl, req, generic_handler, s, USEC_INFINITY, NULL); |
| if (r < 0) |
| return r; |
| |
| s->n_messages ++; |
| return 0; |
| } |
| |
| static bool check_loopback(sd_netlink *rtnl) { |
| _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL; |
| unsigned flags; |
| int r; |
| |
| r = sd_rtnl_message_new_link(rtnl, &req, RTM_GETLINK, LOOPBACK_IFINDEX); |
| if (r < 0) |
| return false; |
| |
| r = sd_netlink_call(rtnl, req, USEC_INFINITY, &reply); |
| if (r < 0) |
| return false; |
| |
| r = sd_rtnl_message_link_get_flags(reply, &flags); |
| if (r < 0) |
| return false; |
| |
| return flags & IFF_UP; |
| } |
| |
| int loopback_setup(void) { |
| _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL; |
| struct state state_4 = { |
| .error_message = "Failed to add address 127.0.0.1 to loopback interface", |
| .success_message = "Successfully added address 127.0.0.1 to loopback interface", |
| }, state_6 = { |
| .error_message = "Failed to add address ::1 to loopback interface", |
| .success_message = "Successfully added address ::1 to loopback interface", |
| }, state_up = { |
| .error_message = "Failed to bring loopback interface up", |
| .success_message = "Successfully brought loopback interface up", |
| }; |
| int r; |
| |
| r = sd_netlink_open(&rtnl); |
| if (r < 0) |
| return log_error_errno(r, "Failed to open netlink: %m"); |
| |
| /* Note that we add the IP addresses here explicitly even though the kernel does that too implicitly when |
| * setting up the loopback device. The reason we do this here a second time (and possibly race against the |
| * kernel) is that we want to synchronously wait until the IP addresses are set up correctly, see |
| * |
| * https://github.com/systemd/systemd/issues/5641 */ |
| |
| r = add_ipv4_address(rtnl, &state_4); |
| if (r < 0) |
| return log_error_errno(r, "Failed to enqueue IPv4 loopback address add request: %m"); |
| |
| r = add_ipv6_address(rtnl, &state_6); |
| if (r < 0) |
| return log_error_errno(r, "Failed to enqueue IPv6 loopback address add request: %m"); |
| |
| r = start_loopback(rtnl, &state_up); |
| if (r < 0) |
| return log_error_errno(r, "Failed to enqueue loopback interface start request: %m"); |
| |
| while (state_4.n_messages + state_6.n_messages + state_up.n_messages > 0) { |
| r = sd_netlink_wait(rtnl, LOOPBACK_SETUP_TIMEOUT_USEC); |
| if (r < 0) |
| return log_error_errno(r, "Failed to wait for netlink event: %m"); |
| |
| r = sd_netlink_process(rtnl, NULL); |
| if (r < 0) |
| return log_warning_errno(r, "Failed to process netlink event: %m"); |
| } |
| |
| /* Note that we don't really care whether the addresses could be added or not */ |
| if (state_up.rcode != 0) { |
| /* If we lack the permissions to configure the loopback device, |
| * but we find it to be already configured, let's exit cleanly, |
| * in order to supported unprivileged containers. */ |
| if (state_up.rcode == -EPERM && check_loopback(rtnl)) |
| return 0; |
| |
| return log_warning_errno(state_up.rcode, "Failed to configure loopback device: %m"); |
| } |
| |
| return 0; |
| } |