From 94bcb43713447d943c5123dc8baac96c4e37bb26 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Wed, 4 Jan 2023 16:36:15 +0100 Subject: [PATCH] resolvectl: don't filter loopback DNS server from global DNS server list "resolvectl status" shows per-link DNS servers separately from global ones. When querying the global list, it will contain both per-link and global servers however. Thus, to not show duplicate info we filter all entries that actually have a non-zero ifindex set (under the assumption that that's a per-link server). This doesn't work if people configured 127.0.0.1 as global server though, as we'll add ifindex 1 to it since 6e32414a66ff8dbcef233981a7066684d903ee9f unconditionally even for global servers. Let's address that by excluding entries with ifindex 1 from suppression. This is safe as resolved ignores loopback ifaces, hence never will have per-link servers on ifindex 1. Note that this splits up the "with_ifindex" parameter into a second parameter "only_global", since they semantically do two different things. One controls whether we shall expect/parse an ifindex dbus field. The other controls whether we shall filter all ifindex values set != 0. These are effectively always used in conjunction hence making them the same actually worked. However this is utterly confusing I think, which as I guess is resulting in the confusion around #25796 (which removes the whole check) (cherry picked from commit 889a1b9f4e799b31f1be06db74708aa8beb70829) Resolves: #2161260 --- src/resolve/resolvectl.c | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/src/resolve/resolvectl.c b/src/resolve/resolvectl.c index 1cb16430e4..e22e06d054 100644 --- a/src/resolve/resolvectl.c +++ b/src/resolve/resolvectl.c @@ -1205,7 +1205,13 @@ static int reset_server_features(int argc, char **argv, void *userdata) { return 0; } -static int read_dns_server_one(sd_bus_message *m, bool with_ifindex, bool extended, char **ret) { +static int read_dns_server_one( + sd_bus_message *m, + bool with_ifindex, /* read "ifindex" reply that also carries an interface index */ + bool extended, /* read "extended" reply, i.e. with port number and server name */ + bool only_global, /* suppress entries with an (non-loopback) ifindex set (i.e. which are specific to some interface) */ + char **ret) { + _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL; _cleanup_free_ char *pretty = NULL; union in_addr_union a; @@ -1255,8 +1261,8 @@ static int read_dns_server_one(sd_bus_message *m, bool with_ifindex, bool extend return 1; } - if (with_ifindex && ifindex != 0) { - /* only show the global ones here */ + if (only_global && ifindex > 0 && ifindex != LOOPBACK_IFINDEX) { + /* This one has an (non-loopback) ifindex set, and we were told to suppress those. Hence do so. */ *ret = NULL; return 1; } @@ -1284,7 +1290,7 @@ static int map_link_dns_servers_internal(sd_bus *bus, const char *member, sd_bus for (;;) { _cleanup_free_ char *pretty = NULL; - r = read_dns_server_one(m, false, extended, &pretty); + r = read_dns_server_one(m, /* with_ifindex= */ false, extended, /* only_global= */ false, &pretty); if (r < 0) return r; if (r == 0) @@ -1317,14 +1323,14 @@ static int map_link_current_dns_server(sd_bus *bus, const char *member, sd_bus_m assert(m); assert(userdata); - return read_dns_server_one(m, false, false, userdata); + return read_dns_server_one(m, /* with_ifindex= */ false, /* extended= */ false, /* only_global= */ false, userdata); } static int map_link_current_dns_server_ex(sd_bus *bus, const char *member, sd_bus_message *m, sd_bus_error *error, void *userdata) { assert(m); assert(userdata); - return read_dns_server_one(m, false, true, userdata); + return read_dns_server_one(m, /* with_ifindex= */ false, /* extended= */ true, /* only_global= */ false, userdata); } static int read_domain_one(sd_bus_message *m, bool with_ifindex, char **ret) { @@ -1756,7 +1762,7 @@ static int map_global_dns_servers_internal( for (;;) { _cleanup_free_ char *pretty = NULL; - r = read_dns_server_one(m, true, extended, &pretty); + r = read_dns_server_one(m, /* with_ifindex= */ true, extended, /* only_global= */ true, &pretty); if (r < 0) return r; if (r == 0) @@ -1786,17 +1792,11 @@ static int map_global_dns_servers_ex(sd_bus *bus, const char *member, sd_bus_mes } static int map_global_current_dns_server(sd_bus *bus, const char *member, sd_bus_message *m, sd_bus_error *error, void *userdata) { - assert(m); - assert(userdata); - - return read_dns_server_one(m, true, false, userdata); + return read_dns_server_one(m, /* with_ifindex= */ true, /* extended= */ false, /* only_global= */ true, userdata); } static int map_global_current_dns_server_ex(sd_bus *bus, const char *member, sd_bus_message *m, sd_bus_error *error, void *userdata) { - assert(m); - assert(userdata); - - return read_dns_server_one(m, true, true, userdata); + return read_dns_server_one(m, /* with_ifindex= */ true, /* extended= */ true, /* only_global= */ true, userdata); } static int map_global_domains(sd_bus *bus, const char *member, sd_bus_message *m, sd_bus_error *error, void *userdata) {