implement new dns backend, res_send and other legacy resolver functions

this is the second phase of the "resolver overhaul" project.

the key additions in this commit are the __res_msend and __res_mkquery
functions, which have been factored so as to provide a backend for
both the legacy res_* functions and the standard getaddrinfo and
getnameinfo functions. the latter however are still using the old
backend code; there is code duplication which still needs to be
removed, and this will be the next phase of the resolver overhaul.

__res_msend is derived from the old __dns_doqueries function, but
generalized to send arbitrary caller-provided packets in parallel
rather than producing the parallel queries itself. this allows it to
be used (completely trivially) as a backend for res_send. the
factored-out query generation code, with slightly more generality, is
now part of __res_mkquery.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/network/res_init.c b/src/network/res_init.c
index cbd5b155..5dba9dfc 100644
--- a/src/network/res_init.c
+++ b/src/network/res_init.c
@@ -1,3 +1,5 @@
+#include <resolv.h>
+
 int res_init()
 {
 	return 0;