X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fresolve%2Fresolved-manager.c;h=74f4ad5dba40c3494bf51675b03270724a678d6d;hb=a5a807e63a50314e190e9166d8a453cd8dd258e3;hp=a93f4a597f76734e5f82c60fc8b52b21f9009cb4;hpb=a407657425a3e47fd2b559cd3bc800f791303f63;p=elogind.git diff --git a/src/resolve/resolved-manager.c b/src/resolve/resolved-manager.c index a93f4a597..74f4ad5db 100644 --- a/src/resolve/resolved-manager.c +++ b/src/resolve/resolved-manager.c @@ -34,6 +34,7 @@ #include "socket-util.h" #include "af-list.h" #include "utf8.h" +#include "fileio-label.h" #include "resolved-dns-domain.h" #include "resolved-conf.h" @@ -426,30 +427,33 @@ static int manager_llmnr_start(Manager *m) { if (r < 0) return r; - r = manager_llmnr_ipv6_udp_fd(m); - if (r == -EADDRINUSE) - goto eaddrinuse; - if (r < 0) - return r; - r = manager_llmnr_ipv4_tcp_fd(m); if (r == -EADDRINUSE) goto eaddrinuse; if (r < 0) return r; - r = manager_llmnr_ipv6_tcp_fd(m); - if (r == -EADDRINUSE) - goto eaddrinuse; - if (r < 0) - return r; + if (socket_ipv6_is_supported()) { + r = manager_llmnr_ipv6_udp_fd(m); + if (r == -EADDRINUSE) + goto eaddrinuse; + if (r < 0) + return r; + + r = manager_llmnr_ipv6_tcp_fd(m); + if (r == -EADDRINUSE) + goto eaddrinuse; + if (r < 0) + return r; + } return 0; eaddrinuse: - log_warning("There appears to be another LLMNR respondering running. Turning off LLMNR support."); + log_warning("There appears to be another LLMNR responder running. Turning off LLMNR support."); m->llmnr_support = SUPPORT_NO; manager_llmnr_stop(m); + return 0; } @@ -536,10 +540,8 @@ Manager *manager_free(Manager *m) { dns_scope_free(m->unicast_scope); - while (m->dns_servers) - dns_server_free(m->dns_servers); - while (m->fallback_dns_servers) - dns_server_free(m->fallback_dns_servers); + manager_flush_dns_servers(m, DNS_SERVER_SYSTEM); + manager_flush_dns_servers(m, DNS_SERVER_FALLBACK); hashmap_free(m->links); hashmap_free(m->dns_transactions); @@ -554,6 +556,7 @@ Manager *manager_free(Manager *m) { manager_llmnr_stop(m); + sd_bus_slot_unref(m->prepare_for_sleep_slot); sd_event_source_unref(m->bus_retry_event_source); sd_bus_unref(m->bus); @@ -675,7 +678,7 @@ clear: return r; } -static void write_resolve_conf_server(DnsServer *s, FILE *f, unsigned *count) { +static void write_resolv_conf_server(DnsServer *s, FILE *f, unsigned *count) { _cleanup_free_ char *t = NULL; int r; @@ -690,17 +693,72 @@ static void write_resolve_conf_server(DnsServer *s, FILE *f, unsigned *count) { } if (*count == MAXNS) - fputs("# Too many DNS servers configured, the following entries may be ignored\n", f); + fputs("# Too many DNS servers configured, the following entries may be ignored.\n", f); fprintf(f, "nameserver %s\n", t); (*count) ++; } +static void write_resolv_conf_search(const char *domain, FILE *f, + unsigned *count, unsigned *length) { + assert(domain); + assert(f); + assert(length); + + if (*count >= MAXDNSRCH || + *length + strlen(domain) > 256) { + if (*count == MAXDNSRCH) + fputs(" # Too many search domains configured, remaining ones ignored.", f); + if (*length <= 256) + fputs(" # Total length of all search domains is too long, remaining ones ignored.", f); + + return; + } + + fprintf(f, " %s", domain); + + (*length) += strlen(domain); + (*count) ++; +} + +static int write_resolv_conf_contents(FILE *f, Set *dns, Set *domains) { + Iterator i; + + 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); + + if (set_isempty(dns)) + fputs("# No DNS servers known.\n", f); + else { + DnsServer *s; + unsigned count = 0; + + SET_FOREACH(s, dns, i) + write_resolv_conf_server(s, f, &count); + } + + if (!set_isempty(domains)) { + unsigned length = 0, count = 0; + char *domain; + + fputs("search", f); + SET_FOREACH(domain, domains, i) + write_resolv_conf_search(domain, f, &count, &length); + fputs("\n", f); + } + + return fflush_and_check(f); +} + + int manager_write_resolv_conf(Manager *m) { static const char path[] = "/run/systemd/resolve/resolv.conf"; _cleanup_free_ char *temp_path = NULL; _cleanup_fclose_ FILE *f = NULL; - unsigned count = 0; + _cleanup_set_free_ Set *dns = NULL, *domains = NULL; DnsServer *s; Iterator i; Link *l; @@ -711,31 +769,66 @@ int manager_write_resolv_conf(Manager *m) { /* Read the system /etc/resolv.conf first */ manager_read_resolv_conf(m); - r = fopen_temporary(path, &f, &temp_path); - if (r < 0) - return r; + /* Add the full list to a set, to filter out duplicates */ + dns = set_new(&dns_server_hash_ops); + if (!dns) + return -ENOMEM; - fchmod(fileno(f), 0644); + domains = set_new(&dns_name_hash_ops); + if (!domains) + return -ENOMEM; - 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); + /* First add the system-wide servers */ + LIST_FOREACH(servers, s, m->dns_servers) { + r = set_put(dns, s); + if (r == -EEXIST) + continue; + if (r < 0) + return r; + } - LIST_FOREACH(servers, s, m->dns_servers) - write_resolve_conf_server(s, f, &count); + /* Then, add the per-link servers and domains */ + HASHMAP_FOREACH(l, m->links, i) { + char **domain; - HASHMAP_FOREACH(l, m->links, i) - LIST_FOREACH(servers, s, l->dns_servers) - write_resolve_conf_server(s, f, &count); + LIST_FOREACH(servers, s, l->dns_servers) { + r = set_put(dns, s); + if (r == -EEXIST) + continue; + if (r < 0) + return r; + } + + if (!l->unicast_scope) + continue; + + STRV_FOREACH(domain, l->unicast_scope->domains) { + r = set_put(domains, *domain); + if (r == -EEXIST) + continue; + if (r < 0) + return r; + } + } - if (count == 0) { - LIST_FOREACH(servers, s, m->fallback_dns_servers) - write_resolve_conf_server(s, f, &count); + /* If we found nothing, add the fallback servers */ + if (set_isempty(dns)) { + LIST_FOREACH(servers, s, m->fallback_dns_servers) { + r = set_put(dns, s); + if (r == -EEXIST) + continue; + if (r < 0) + return r; + } } - r = fflush_and_check(f); + r = fopen_temporary_label(path, path, &f, &temp_path); + if (r < 0) + return r; + + fchmod(fileno(f), 0644); + + r = write_resolv_conf_contents(f, dns, domains); if (r < 0) goto fail; @@ -756,7 +849,7 @@ int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) { _cleanup_(dns_packet_unrefp) DnsPacket *p = NULL; union { struct cmsghdr header; /* For alignment */ - uint8_t buffer[CMSG_SPACE(MAX(sizeof(struct in_pktinfo), sizeof(struct in6_pktinfo))) + uint8_t buffer[CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo)) + CMSG_SPACE(int) /* ttl/hoplimit */ + EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */]; } control; @@ -1602,6 +1695,9 @@ fail: return r; } +/* lo having ifindex 1 is hardcoded in the kernel */ +#define LOOPBACK_IFINDEX 1 + int manager_ifindex_is_loopback(Manager *m, int ifindex) { Link *l; assert(m); @@ -1610,7 +1706,10 @@ int manager_ifindex_is_loopback(Manager *m, int ifindex) { return -EINVAL; l = hashmap_get(m->links, INT_TO_PTR(ifindex)); - if (l->flags & IFF_LOOPBACK) + if (!l) + /* in case we don't yet track the link, rely on the hardcoded value */ + return ifindex == LOOPBACK_IFINDEX; + else if (l->flags & IFF_LOOPBACK) return 1; return 0; @@ -1645,7 +1744,7 @@ void manager_refresh_rrs(Manager *m) { int manager_next_hostname(Manager *m) { const char *p; - uint64_t u; + uint64_t u, a; char *h; assert(m); @@ -1663,7 +1762,15 @@ int manager_next_hostname(Manager *m) { if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0) u = 1; - u++; + /* Add a random number to the old value. This way we can avoid + * that two hosts pick the same hostname, win on IPv4 and lose + * on IPv6 (or vice versa), and pick the same hostname + * replacement hostname, ad infinitum. We still want the + * numbers to go up monotonically, hence we just add a random + * value 1..10 */ + + random_bytes(&a, sizeof(a)); + u += 1 + a % 10; if (asprintf(&h, "%.*s%" PRIu64, (int) (p - m->hostname), m->hostname, u) < 0) return -ENOMEM; @@ -1722,6 +1829,27 @@ DnsScope* manager_find_scope(Manager *m, DnsPacket *p) { return NULL; } +void manager_verify_all(Manager *m) { + DnsScope *s; + + assert(m); + + LIST_FOREACH(scopes, s, m->dns_scopes) + dns_zone_verify_all(&s->zone); +} + +void manager_flush_dns_servers(Manager *m, DnsServerType t) { + assert(m); + + if (t == DNS_SERVER_SYSTEM) + while (m->dns_servers) + dns_server_free(m->dns_servers); + + if (t == DNS_SERVER_FALLBACK) + while (m->fallback_dns_servers) + dns_server_free(m->fallback_dns_servers); +} + static const char* const support_table[_SUPPORT_MAX] = { [SUPPORT_NO] = "no", [SUPPORT_YES] = "yes",