DnsServer *manager_get_dns_server(Manager *m) { Link *l; assert(m); /* Try to read updates resolv.conf */ manager_read_resolv_conf(m); /* If no DNS server was chosen so far, pick the first one */ if (!m->current_dns_server) manager_set_dns_server(m, m->dns_servers); if (!m->current_dns_server) { bool found = false; Iterator i; /* No DNS servers configured, let's see if there are * any on any links. If not, we use the fallback * servers */ HASHMAP_FOREACH(l, m->links, i) if (l->dns_servers) { found = true; break; } if (!found) manager_set_dns_server(m, m->fallback_dns_servers); }
DnsServer* dns_server_free(DnsServer *s) { if (!s) return NULL; if (s->manager) { if (s->type == DNS_SERVER_LINK) LIST_REMOVE(servers, s->link->dns_servers, s); else if (s->type == DNS_SERVER_SYSTEM) LIST_REMOVE(servers, s->manager->dns_servers, s); else if (s->type == DNS_SERVER_FALLBACK) LIST_REMOVE(servers, s->manager->fallback_dns_servers, s); else assert_not_reached("Unknown server type"); if (s->manager->current_dns_server == s) manager_set_dns_server(s->manager, NULL); } if (s->link && s->link->current_dns_server == s) link_set_dns_server(s->link, NULL); free(s); return NULL; }
int dns_server_new( Manager *m, DnsServer **ret, DnsServerType type, Link *l, int family, const union in_addr_union *in_addr) { DnsServer *s, *tail; assert(m); assert((type == DNS_SERVER_LINK) == !!l); assert(in_addr); s = new0(DnsServer, 1); if (!s) return -ENOMEM; s->n_ref = 1; s->type = type; s->family = family; s->address = *in_addr; s->resend_timeout = DNS_TIMEOUT_MIN_USEC; if (type == DNS_SERVER_LINK) { LIST_FIND_TAIL(servers, l->dns_servers, tail); LIST_INSERT_AFTER(servers, l->dns_servers, tail, s); s->link = l; } else if (type == DNS_SERVER_SYSTEM) { LIST_FIND_TAIL(servers, m->dns_servers, tail); LIST_INSERT_AFTER(servers, m->dns_servers, tail, s); } else if (type == DNS_SERVER_FALLBACK) { LIST_FIND_TAIL(servers, m->fallback_dns_servers, tail); LIST_INSERT_AFTER(servers, m->fallback_dns_servers, tail, s); } else assert_not_reached("Unknown server type"); s->manager = m; /* A new DNS server that isn't fallback is added and the one * we used so far was a fallback one? Then let's try to pick * the new one */ if (type != DNS_SERVER_FALLBACK && m->current_dns_server && m->current_dns_server->type == DNS_SERVER_FALLBACK) manager_set_dns_server(m, NULL); if (ret) *ret = s; return 0; }
static DnsServer* dns_server_free(DnsServer *s) { if (!s) return NULL; if (s->link && s->link->current_dns_server == s) link_set_dns_server(s->link, NULL); if (s->manager && s->manager->current_dns_server == s) manager_set_dns_server(s->manager, NULL); free(s); return NULL; }
void dns_server_unlink(DnsServer *s) { assert(s); assert(s->manager); /* This removes the specified server from the linked list of * servers, but any server might still stay around if it has * refs, for example from an ongoing transaction. */ if (!s->linked) return; switch (s->type) { case DNS_SERVER_LINK: assert(s->link); assert(s->link->n_dns_servers > 0); LIST_REMOVE(servers, s->link->dns_servers, s); s->link->n_dns_servers--; break; case DNS_SERVER_SYSTEM: assert(s->manager->n_dns_servers > 0); LIST_REMOVE(servers, s->manager->dns_servers, s); s->manager->n_dns_servers--; break; case DNS_SERVER_FALLBACK: assert(s->manager->n_dns_servers > 0); LIST_REMOVE(servers, s->manager->fallback_dns_servers, s); s->manager->n_dns_servers--; break; } s->linked = false; if (s->link && s->link->current_dns_server == s) link_set_dns_server(s->link, NULL); if (s->manager->current_dns_server == s) manager_set_dns_server(s->manager, NULL); dns_server_unref(s); }
int dns_server_new( Manager *m, DnsServer **ret, DnsServerType type, Link *l, int family, const union in_addr_union *in_addr, int ifindex) { DnsServer *s; assert(m); assert((type == DNS_SERVER_LINK) == !!l); assert(in_addr); if (!IN_SET(family, AF_INET, AF_INET6)) return -EAFNOSUPPORT; if (l) { if (l->n_dns_servers >= LINK_DNS_SERVERS_MAX) return -E2BIG; } else { if (m->n_dns_servers >= MANAGER_DNS_SERVERS_MAX) return -E2BIG; } s = new0(DnsServer, 1); if (!s) return -ENOMEM; s->n_ref = 1; s->manager = m; s->verified_feature_level = _DNS_SERVER_FEATURE_LEVEL_INVALID; s->possible_feature_level = DNS_SERVER_FEATURE_LEVEL_BEST; s->features_grace_period_usec = DNS_SERVER_FEATURE_GRACE_PERIOD_MIN_USEC; s->received_udp_packet_max = DNS_PACKET_UNICAST_SIZE_MAX; s->type = type; s->family = family; s->address = *in_addr; s->ifindex = ifindex; s->resend_timeout = DNS_TIMEOUT_MIN_USEC; switch (type) { case DNS_SERVER_LINK: s->link = l; LIST_APPEND(servers, l->dns_servers, s); l->n_dns_servers++; break; case DNS_SERVER_SYSTEM: LIST_APPEND(servers, m->dns_servers, s); m->n_dns_servers++; break; case DNS_SERVER_FALLBACK: LIST_APPEND(servers, m->fallback_dns_servers, s); m->n_dns_servers++; break; default: assert_not_reached("Unknown server type"); } s->linked = true; /* A new DNS server that isn't fallback is added and the one * we used so far was a fallback one? Then let's try to pick * the new one */ if (type != DNS_SERVER_FALLBACK && m->current_dns_server && m->current_dns_server->type == DNS_SERVER_FALLBACK) manager_set_dns_server(m, NULL); if (ret) *ret = s; return 0; }
int manager_read_resolv_conf(Manager *m) { _cleanup_fclose_ FILE *f = NULL; struct stat st, own; char line[LINE_MAX]; usec_t t; int r; assert(m); /* Reads the system /etc/resolv.conf, if it exists and is not * symlinked to our own resolv.conf instance */ if (!m->read_resolv_conf) return 0; r = stat("/etc/resolv.conf", &st); if (r < 0) { if (errno == ENOENT) return 0; r = log_warning_errno(errno, "Failed to stat /etc/resolv.conf: %m"); goto clear; } /* Have we already seen the file? */ t = timespec_load(&st.st_mtim); if (t == m->resolv_conf_mtime) return 0; /* Is it symlinked to our own file? */ if (stat(PRIVATE_RESOLV_CONF, &own) >= 0 && st.st_dev == own.st_dev && st.st_ino == own.st_ino) return 0; f = fopen("/etc/resolv.conf", "re"); if (!f) { if (errno == ENOENT) return 0; r = log_warning_errno(errno, "Failed to open /etc/resolv.conf: %m"); goto clear; } if (fstat(fileno(f), &st) < 0) { r = log_error_errno(errno, "Failed to stat open file: %m"); goto clear; } dns_server_mark_all(m->dns_servers); dns_search_domain_mark_all(m->search_domains); FOREACH_LINE(line, f, r = -errno; goto clear) { const char *a; char *l; l = strstrip(line); if (IN_SET(*l, '#', ';')) continue; a = first_word(l, "nameserver"); if (a) { r = manager_parse_dns_server_string_and_warn(m, DNS_SERVER_SYSTEM, a); if (r < 0) log_warning_errno(r, "Failed to parse DNS server address '%s', ignoring.", a); continue; } a = first_word(l, "domain"); if (!a) /* We treat "domain" lines, and "search" lines as equivalent, and add both to our list. */ a = first_word(l, "search"); if (a) { r = manager_parse_search_domains_and_warn(m, a); if (r < 0) log_warning_errno(r, "Failed to parse search domain string '%s', ignoring.", a); } } m->resolv_conf_mtime = t; /* Flush out all servers and search domains that are still * marked. Those are then ones that didn't appear in the new * /etc/resolv.conf */ dns_server_unlink_marked(m->dns_servers); dns_search_domain_unlink_marked(m->search_domains); /* Whenever /etc/resolv.conf changes, start using the first * DNS server of it. This is useful to deal with broken * network managing implementations (like NetworkManager), * that when connecting to a VPN place both the VPN DNS * servers and the local ones in /etc/resolv.conf. Without * resetting the DNS server to use back to the first entry we * will continue to use the local one thus being unable to * resolve VPN domains. */ manager_set_dns_server(m, m->dns_servers); /* Unconditionally flush the cache when /etc/resolv.conf is * modified, even if the data it contained was completely * identical to the previous version we used. We do this * because altering /etc/resolv.conf is typically done when * the network configuration changes, and that should be * enough to flush the global unicast DNS cache. */ if (m->unicast_scope) dns_cache_flush(&m->unicast_scope->cache); /* If /etc/resolv.conf changed, make sure to forget everything we learned about the DNS servers. After all we * might now talk to a very different DNS server that just happens to have the same IP address as an old one * (think 192.168.1.1). */ dns_server_reset_features_all(m->dns_servers); return 0; clear: dns_server_unlink_all(m->dns_servers); dns_search_domain_unlink_all(m->search_domains); return r; }
int dns_server_new( Manager *m, DnsServer **ret, DnsServerType type, Link *l, int family, const union in_addr_union *in_addr) { DnsServer *s; assert(m); assert((type == DNS_SERVER_LINK) == !!l); assert(in_addr); if (!IN_SET(family, AF_INET, AF_INET6)) return -EAFNOSUPPORT; if (l) { if (l->n_dns_servers >= LINK_DNS_SERVERS_MAX) return -E2BIG; } else { if (m->n_dns_servers >= MANAGER_DNS_SERVERS_MAX) return -E2BIG; } s = new0(DnsServer, 1); if (!s) return -ENOMEM; s->n_ref = 1; s->manager = m; s->type = type; s->family = family; s->address = *in_addr; s->resend_timeout = DNS_TIMEOUT_MIN_USEC; switch (type) { case DNS_SERVER_LINK: s->link = l; LIST_APPEND(servers, l->dns_servers, s); l->n_dns_servers++; break; case DNS_SERVER_SYSTEM: LIST_APPEND(servers, m->dns_servers, s); m->n_dns_servers++; break; case DNS_SERVER_FALLBACK: LIST_APPEND(servers, m->fallback_dns_servers, s); m->n_dns_servers++; break; default: assert_not_reached("Unknown server type"); } s->linked = true; /* A new DNS server that isn't fallback is added and the one * we used so far was a fallback one? Then let's try to pick * the new one */ if (type != DNS_SERVER_FALLBACK && m->current_dns_server && m->current_dns_server->type == DNS_SERVER_FALLBACK) manager_set_dns_server(m, NULL); if (ret) *ret = s; return 0; }