resolved: use one UDP socket per transaction

We used to have one global socket, use one per transaction instead. This
has the side-effect of giving us a random UDP port per transaction, and
hence increasing the entropy and making cache poisoining significantly
harder to achieve.

We still reuse the same port number for packets belonging to the same
transaction (resent packets).

1 files changed, 4 insertions, 4 deletions

diff --git a/src/resolve/resolved-dns-scope.c b/src/resolve/resolved-dns-scope.c
index 34d4a98e82..7b72c090c2 100644
--- a/src/resolve/resolved-dns-scope.c
+++ b/src/resolve/resolved-dns-scope.c
@@ -125,7 +125,7 @@ void dns_scope_next_dns_server(DnsScope *s) {
                 manager_next_dns_server(s->manager);
 }
 
-int dns_scope_emit(DnsScope *s, DnsPacket *p, DnsServer **server) {
+int dns_scope_emit(DnsScope *s, DnsTransaction *t, DnsPacket *p, DnsServer **server) {
         DnsServer *srv = NULL;
         union in_addr_union addr;
         int ifindex = 0, r;
@@ -163,9 +163,9 @@ int dns_scope_emit(DnsScope *s, DnsPacket *p, DnsServer **server) {
                         return -EMSGSIZE;
 
                 if (family == AF_INET)
-                        fd = manager_dns_ipv4_fd(s->manager);
+                        fd = transaction_dns_ipv4_fd(t);
                 else if (family == AF_INET6)
-                        fd = manager_dns_ipv6_fd(s->manager);
+                        fd = transaction_dns_ipv6_fd(t);
                 else
                         return -EAFNOSUPPORT;
                 if (fd < 0)
@@ -700,7 +700,7 @@ static int on_conflict_dispatch(sd_event_source *es, usec_t usec, void *userdata
                         return 0;
                 }
 
-                r = dns_scope_emit(scope, p, NULL);
+                r = dns_scope_emit(scope, NULL, p, NULL);
                 if (r < 0)
                         log_debug_errno(r, "Failed to send conflict packet: %m");
         }