/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2014 Tom Gundersen <teg@jklm.no> 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 <resolv.h> #include <linux/if.h> #include <sys/ioctl.h> #include <sys/poll.h> #include <netinet/in.h> #include "rtnl-util.h" #include "event-util.h" #include "network-util.h" #include "sd-dhcp-lease.h" #include "dhcp-lease-internal.h" #include "network-internal.h" #include "conf-parser.h" #include "socket-util.h" #include "resolved.h" #define SEND_TIMEOUT_USEC (200 * USEC_PER_MSEC) static int manager_process_link(sd_rtnl *rtnl, sd_rtnl_message *mm, void *userdata) { Manager *m = userdata; uint16_t type; Link *l; int ifindex, r; assert(rtnl); assert(m); assert(mm); r = sd_rtnl_message_get_type(mm, &type); if (r < 0) goto fail; r = sd_rtnl_message_link_get_ifindex(mm, &ifindex); if (r < 0) goto fail; l = hashmap_get(m->links, INT_TO_PTR(ifindex)); switch (type) { case RTM_NEWLINK: if (!l) { log_debug("Found link %i", ifindex); r = link_new(m, &l, ifindex); if (r < 0) goto fail; } r = link_update_rtnl(l, mm); if (r < 0) goto fail; break; case RTM_DELLINK: if (l) { log_debug("Removing link %i", l->ifindex); link_free(l); } break; } return 0; fail: log_warning("Failed to process RTNL link message: %s", strerror(-r)); return 0; } static int manager_process_address(sd_rtnl *rtnl, sd_rtnl_message *mm, void *userdata) { Manager *m = userdata; union in_addr_union address; unsigned char family; uint16_t type; int r, ifindex; LinkAddress *a; Link *l; assert(rtnl); assert(mm); assert(m); r = sd_rtnl_message_get_type(mm, &type); if (r < 0) goto fail; r = sd_rtnl_message_addr_get_ifindex(mm, &ifindex); if (r < 0) goto fail; l = hashmap_get(m->links, INT_TO_PTR(ifindex)); if (!l) return 0; r = sd_rtnl_message_addr_get_family(mm, &family); if (r < 0) goto fail; switch (family) { case AF_INET: r = sd_rtnl_message_read_in_addr(mm, IFA_LOCAL, &address.in); if (r < 0) { r = sd_rtnl_message_read_in_addr(mm, IFA_ADDRESS, &address.in); if (r < 0) goto fail; } break; case AF_INET6: r = sd_rtnl_message_read_in6_addr(mm, IFA_LOCAL, &address.in6); if (r < 0) { r = sd_rtnl_message_read_in6_addr(mm, IFA_ADDRESS, &address.in6); if (r < 0) goto fail; } break; default: return 0; } a = link_find_address(l, family, &address); switch (type) { case RTM_NEWADDR: if (!a) { r = link_address_new(l, &a, family, &address); if (r < 0) return r; } r = link_address_update_rtnl(a, mm); if (r < 0) return r; break; case RTM_DELADDR: if (a) link_address_free(a); break; } return 0; fail: log_warning("Failed to process RTNL address message: %s", strerror(-r)); return 0; } static int manager_rtnl_listen(Manager *m) { _cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL, *reply = NULL; sd_rtnl_message *i; int r; assert(m); /* First, subscibe to interfaces coming and going */ r = sd_rtnl_open(&m->rtnl, 3, RTNLGRP_LINK, RTNLGRP_IPV4_IFADDR, RTNLGRP_IPV6_IFADDR); if (r < 0) return r; r = sd_rtnl_attach_event(m->rtnl, m->event, 0); if (r < 0) return r; r = sd_rtnl_add_match(m->rtnl, RTM_NEWLINK, manager_process_link, m); if (r < 0) return r; r = sd_rtnl_add_match(m->rtnl, RTM_DELLINK, manager_process_link, m); if (r < 0) return r; r = sd_rtnl_add_match(m->rtnl, RTM_NEWADDR, manager_process_address, m); if (r < 0) return r; r = sd_rtnl_add_match(m->rtnl, RTM_DELADDR, manager_process_address, m); if (r < 0) return r; /* Then, enumerate all links */ r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0); if (r < 0) return r; r = sd_rtnl_message_request_dump(req, true); if (r < 0) return r; r = sd_rtnl_call(m->rtnl, req, 0, &reply); if (r < 0) return r; for (i = reply; i; i = sd_rtnl_message_next(i)) { r = manager_process_link(m->rtnl, i, m); if (r < 0) return r; } req = sd_rtnl_message_unref(req); reply = sd_rtnl_message_unref(reply); /* Finally, enumerate all addresses, too */ r = sd_rtnl_message_new_addr(m->rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC); if (r < 0) return r; r = sd_rtnl_message_request_dump(req, true); if (r < 0) return r; r = sd_rtnl_call(m->rtnl, req, 0, &reply); if (r < 0) return r; for (i = reply; i; i = sd_rtnl_message_next(i)) { r = manager_process_address(m->rtnl, i, m); if (r < 0) return r; } return r; } static int on_network_event(sd_event_source *s, int fd, uint32_t revents, void *userdata) { Manager *m = userdata; Iterator i; Link *l; int r; assert(m); sd_network_monitor_flush(m->network_monitor); HASHMAP_FOREACH(l, m->links, i) { r = link_update_monitor(l); if (r < 0) log_warning("Failed to update monitor information for %i: %s", l->ifindex, strerror(-r)); } r = manager_write_resolv_conf(m); if (r < 0) log_warning("Could not update resolv.conf: %s", strerror(-r)); return 0; } static int manager_network_monitor_listen(Manager *m) { int r, fd, events; assert(m); r = sd_network_monitor_new(&m->network_monitor, NULL); if (r < 0) return r; fd = sd_network_monitor_get_fd(m->network_monitor); if (fd < 0) return fd; events = sd_network_monitor_get_events(m->network_monitor); if (events < 0) return events; r = sd_event_add_io(m->event, &m->network_event_source, fd, events, &on_network_event, m); if (r < 0) return r; return 0; } static int parse_dns_server_string(Manager *m, const char *string) { char *word, *state; size_t length; int r; assert(m); assert(string); FOREACH_WORD_QUOTED(word, length, string, state) { char buffer[length+1]; unsigned family; union in_addr_union addr; memcpy(buffer, word, length); buffer[length] = 0; r = in_addr_from_string_auto(buffer, &family, &addr); if (r < 0) { log_warning("Ignoring invalid DNS address '%s'", buffer); continue; } /* filter out duplicates */ if (manager_find_dns_server(m, family, &addr)) continue; r = dns_server_new(m, NULL, DNS_SERVER_SYSTEM, NULL, family, &addr); if (r < 0) return r; } return 0; } int config_parse_dnsv( const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata) { Manager *m = userdata; int r; assert(filename); assert(lvalue); assert(rvalue); assert(m); /* Empty assignment means clear the list */ if (isempty(rvalue)) { while (m->dns_servers) dns_server_free(m->dns_servers); return 0; } r = parse_dns_server_string(m, rvalue); if (r < 0) { log_error("Failed to parse DNS server string"); return r; } return 0; } int manager_parse_config_file(Manager *m) { assert(m); return config_parse(NULL, "/etc/systemd/resolved.conf", NULL, "Resolve\0", config_item_perf_lookup, resolved_gperf_lookup, false, false, true, m); } int manager_new(Manager **ret) { _cleanup_(manager_freep) Manager *m = NULL; int r; assert(ret); m = new0(Manager, 1); if (!m) return -ENOMEM; m->dns_ipv4_fd = m->dns_ipv6_fd = -1; r = parse_dns_server_string(m, /* "172.31.0.125 2001:4860:4860::8888 2001:4860:4860::8889" */ DNS_SERVERS); if (r < 0) return r; r = sd_event_default(&m->event); if (r < 0) return r; sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL); sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL); sd_event_set_watchdog(m->event, true); r = dns_scope_new(m, &m->unicast_scope, DNS_SCOPE_DNS); if (r < 0) return r; r = manager_network_monitor_listen(m); if (r < 0) return r; r = manager_rtnl_listen(m); if (r < 0) return r; r = manager_connect_bus(m); if (r < 0) return r; *ret = m; m = NULL; return 0; } Manager *manager_free(Manager *m) { Link *l; if (!m) return NULL; while (m->dns_queries) dns_query_free(m->dns_queries); hashmap_free(m->dns_query_transactions); while ((l = hashmap_first(m->links))) link_free(l); hashmap_free(m->links); dns_scope_free(m->unicast_scope); while (m->dns_servers) dns_server_free(m->dns_servers); sd_event_source_unref(m->network_event_source); sd_network_monitor_unref(m->network_monitor); sd_event_source_unref(m->dns_ipv4_event_source); sd_event_source_unref(m->dns_ipv6_event_source); safe_close(m->dns_ipv4_fd); safe_close(m->dns_ipv6_fd); sd_event_source_unref(m->bus_retry_event_source); sd_bus_unref(m->bus); sd_event_unref(m->event); free(m); return NULL; } static void write_resolve_conf_server(DnsServer *s, FILE *f, unsigned *count) { _cleanup_free_ char *t = NULL; int r; assert(s); assert(f); assert(count); r = in_addr_to_string(s->family, &s->address, &t); if (r < 0) { log_warning("Invalid DNS address. Ignoring."); return; } if (*count == MAXNS) fputs("# Too many DNS servers configured, the following entries may be ignored\n", f); fprintf(f, "nameserver %s\n", t); (*count) ++; } int manager_write_resolv_conf(Manager *m) { const char *path = "/run/systemd/resolve/resolv.conf"; _cleanup_free_ char *temp_path = NULL; _cleanup_fclose_ FILE *f = NULL; unsigned count = 0; DnsServer *s; Iterator i; Link *l; int r; assert(m); r = fopen_temporary(path, &f, &temp_path); if (r < 0) return r; fchmod(fileno(f), 0644); fputs("# This file is managed by systemd-resolved(8). Do not edit.\n#\n" "# Third party programs must not access this file directly, but\n" "# only through the symlink at /etc/resolv.conf. To manage\n" "# resolv.conf(5) in a different way, replace the symlink by a\n" "# static file or a different symlink.\n\n", f); HASHMAP_FOREACH(l, m->links, i) { LIST_FOREACH(servers, s, l->link_dns_servers) write_resolve_conf_server(s, f, &count); LIST_FOREACH(servers, s, l->dhcp_dns_servers) write_resolve_conf_server(s, f, &count); } LIST_FOREACH(servers, s, m->dns_servers) write_resolve_conf_server(s, f, &count); r = fflush_and_check(f); if (r < 0) goto fail; if (rename(temp_path, path) < 0) { r = -errno; goto fail; } return 0; fail: unlink(path); unlink(temp_path); return r; } int manager_dns_ipv4_recv(Manager *m, DnsPacket **ret) { _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; struct msghdr mh = {}; int fd, ms = 0, r; struct iovec iov; ssize_t l; assert(m); assert(ret); fd = manager_dns_ipv4_fd(m); if (fd < 0) return fd; r = ioctl(fd, FIONREAD, &ms); if (r < 0) return -errno; if (ms < 0) return -EIO; r = dns_packet_new(&p, ms); if (r < 0) return r; iov.iov_base = DNS_PACKET_DATA(p); iov.iov_len = p->allocated; mh.msg_iov = &iov; mh.msg_iovlen = 1; l = recvmsg(fd, &mh, 0); if (l < 0) { if (errno == EAGAIN || errno == EINTR) return 0; return -errno; } if (l <= 0) return -EIO; p->size = (size_t) l; *ret = p; p = NULL; return 1; } int manager_dns_ipv6_recv(Manager *m, DnsPacket **ret) { _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; struct msghdr mh = {}; struct iovec iov; int fd, ms = 0, r; ssize_t l; assert(m); assert(ret); fd = manager_dns_ipv6_fd(m); if (fd < 0) return fd; r = ioctl(fd, FIONREAD, &ms); if (r < 0) return -errno; if (ms < 0) return -EIO; r = dns_packet_new(&p, ms); if (r < 0) return r; iov.iov_base = DNS_PACKET_DATA(p); iov.iov_len = p->allocated; mh.msg_iov = &iov; mh.msg_iovlen = 1; l = recvmsg(fd, &mh, 0); if (l < 0) { if (errno == EAGAIN || errno == EINTR) return 0; return -errno; } if (l <= 0) return -EIO; p->size = (size_t) l; *ret = p; p = NULL; return 1; } static int on_dns_ipv4_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; DnsQueryTransaction *t = NULL; Manager *m = userdata; int r; r = manager_dns_ipv4_recv(m, &p); if (r <= 0) return r; t = hashmap_get(m->dns_query_transactions, UINT_TO_PTR(DNS_PACKET_ID(p))); if (!t) return 0; dns_query_transaction_reply(t, p); return 0; } static int on_dns_ipv6_packet(sd_event_source *s, int fd, uint32_t revents, void *userdata) { _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; DnsQueryTransaction *t = NULL; Manager *m = userdata; int r; r = manager_dns_ipv6_recv(m, &p); if (r <= 0) return r; t = hashmap_get(m->dns_query_transactions, UINT_TO_PTR(DNS_PACKET_ID(p))); if (!t) return 0; dns_query_transaction_reply(t, p); return 0; } int manager_dns_ipv4_fd(Manager *m) { int r; assert(m); if (m->dns_ipv4_fd >= 0) return m->dns_ipv4_fd; m->dns_ipv4_fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); if (m->dns_ipv4_fd < 0) return -errno; r = sd_event_add_io(m->event, &m->dns_ipv4_event_source, m->dns_ipv4_fd, EPOLLIN, on_dns_ipv4_packet, m); if (r < 0) return r; return m->dns_ipv4_fd; } int manager_dns_ipv6_fd(Manager *m) { int r; assert(m); if (m->dns_ipv6_fd >= 0) return m->dns_ipv6_fd; m->dns_ipv6_fd = socket(AF_INET6, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); if (m->dns_ipv6_fd < 0) return -errno; r = sd_event_add_io(m->event, &m->dns_ipv6_event_source, m->dns_ipv6_fd, EPOLLIN, on_dns_ipv6_packet, m); if (r < 0) return r; return m->dns_ipv6_fd; } static int sendmsg_loop(int fd, struct msghdr *mh, int flags) { int r; assert(fd >= 0); assert(mh); for (;;) { if (sendmsg(fd, mh, flags) >= 0) return 0; if (errno == EINTR) continue; if (errno != EAGAIN) return -errno; r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC); if (r < 0) return r; if (r == 0) return -ETIMEDOUT; } } int manager_dns_ipv4_send(Manager *m, DnsServer *srv, int ifindex, DnsPacket *p) { union sockaddr_union sa = { .in.sin_family = AF_INET, .in.sin_port = htobe16(53), }; struct msghdr mh = {}; struct iovec iov; uint8_t control[CMSG_SPACE(sizeof(struct in_pktinfo))]; int fd; assert(m); assert(srv); assert(p); fd = manager_dns_ipv4_fd(m); if (fd < 0) return fd; iov.iov_base = DNS_PACKET_DATA(p); iov.iov_len = p->size; sa.in.sin_addr = srv->address.in; mh.msg_iov = &iov; mh.msg_iovlen = 1; mh.msg_name = &sa.sa; mh.msg_namelen = sizeof(sa.in); if (ifindex > 0) { struct cmsghdr *cmsg; struct in_pktinfo *pi; zero(control); mh.msg_control = control; mh.msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo)); cmsg = CMSG_FIRSTHDR(&mh); cmsg->cmsg_len = mh.msg_controllen; cmsg->cmsg_level = IPPROTO_IP; cmsg->cmsg_type = IP_PKTINFO; pi = (struct in_pktinfo*) CMSG_DATA(cmsg); pi->ipi_ifindex = ifindex; } return sendmsg_loop(fd, &mh, 0); } int manager_dns_ipv6_send(Manager *m, DnsServer *srv, int ifindex, DnsPacket *p) { union sockaddr_union sa = { .in6.sin6_family = AF_INET6, .in6.sin6_port = htobe16(53), }; struct msghdr mh = {}; struct iovec iov; uint8_t control[CMSG_SPACE(sizeof(struct in6_pktinfo))]; int fd; assert(m); assert(srv); assert(p); fd = manager_dns_ipv6_fd(m); if (fd < 0) return fd; iov.iov_base = DNS_PACKET_DATA(p); iov.iov_len = p->size; sa.in6.sin6_addr = srv->address.in6; sa.in6.sin6_scope_id = ifindex; mh.msg_iov = &iov; mh.msg_iovlen = 1; mh.msg_name = &sa.sa; mh.msg_namelen = sizeof(sa.in6); if (ifindex > 0) { struct cmsghdr *cmsg; struct in6_pktinfo *pi; zero(control); mh.msg_control = control; mh.msg_controllen = CMSG_LEN(sizeof(struct in6_pktinfo)); cmsg = CMSG_FIRSTHDR(&mh); cmsg->cmsg_len = mh.msg_controllen; cmsg->cmsg_level = IPPROTO_IPV6; cmsg->cmsg_type = IPV6_PKTINFO; pi = (struct in6_pktinfo*) CMSG_DATA(cmsg); pi->ipi6_ifindex = ifindex; } return sendmsg_loop(fd, &mh, 0); } DnsServer* manager_find_dns_server(Manager *m, unsigned char family, union in_addr_union *in_addr) { DnsServer *s; assert(m); assert(in_addr); LIST_FOREACH(servers, s, m->dns_servers) { if (s->family == family && in_addr_equal(family, &s->address, in_addr)) return s; } return NULL; } DnsServer *manager_get_dns_server(Manager *m) { assert(m); if (!m->current_dns_server) m->current_dns_server = m->dns_servers; return m->current_dns_server; } void manager_next_dns_server(Manager *m) { assert(m); if (!m->current_dns_server) { m->current_dns_server = m->dns_servers; return; } if (!m->current_dns_server) return; if (m->current_dns_server->servers_next) { m->current_dns_server = m->current_dns_server->servers_next; return; } m->current_dns_server = m->dns_servers; } uint32_t manager_find_mtu(Manager *m) { uint32_t mtu = 0; Link *l; Iterator i; /* If we don't know on which link a DNS packet would be * delivered, let's find the largest MTU that works on all * interfaces we know of */ HASHMAP_FOREACH(l, m->links, i) { if (l->mtu <= 0) continue; if (mtu <= 0 || l->mtu < mtu) mtu = l->mtu; } return mtu; }