Replace ad-hoc DNS message buffer in client code with isc_buffer_t

The commit replaces an ad-hoc incoming DNS-message buffer in the
client-side DoH code with isc_buffer_t.

The commit also fixes a timing issue in the unit tests revealed by the
change.

diff --git a/lib/isc/netmgr/http.c b/lib/isc/netmgr/http.c
index d32b908191b1cee007b9c377a059b9d61894ca24..f3dabbd6105127199f88d7166cb3293f1ea12114 100644 (file)
--- a/lib/isc/netmgr/http.c
+++ b/lib/isc/netmgr/http.c
@@ -74,6 +74,8 @@
        ((code) >= MIN_SUCCESSFUL_HTTP_STATUS && \
         (code) <= MAX_SUCCESSFUL_HTTP_STATUS)
 
+#define INITIAL_DNS_MESSAGE_BUFFER_SIZE (512)
+
 typedef struct isc_nm_http_response_status {
        size_t code;
        size_t content_length;
@@ -96,8 +98,7 @@ typedef struct http_cstream {
        size_t authoritylen;
        char *path;
 
-       uint8_t rbuf[MAX_DNS_MESSAGE_SIZE];
-       size_t rbufsize;
+       isc_buffer_t *rbuf;
 
        size_t pathlen;
        int32_t stream_id;
@@ -426,6 +427,10 @@ new_http_cstream(isc_nmsocket_t *sock, http_cstream_t **streamp) {
                        stream->up.field_data[ISC_UF_QUERY].len);
        }
 
+       isc_buffer_allocate(mctx, &stream->rbuf,
+                           INITIAL_DNS_MESSAGE_BUFFER_SIZE);
+       isc_buffer_setautorealloc(stream->rbuf, true);
+
        ISC_LIST_PREPEND(sock->h2.session->cstreams, stream, link);
        *streamp = stream;
 
@@ -455,6 +460,8 @@ put_http_cstream(isc_mem_t *mctx, http_cstream_t *stream) {
                                link);
        }
        isc__nmsocket_detach(&stream->httpsock);
+
+       isc_buffer_free(&stream->rbuf);
        isc_mem_put(mctx, stream, sizeof(http_cstream_t));
 }
 
@@ -506,12 +513,13 @@ on_client_data_chunk_recv_callback(int32_t stream_id, const uint8_t *data,
        http_cstream_t *cstream = find_http_cstream(stream_id, session);
 
        if (cstream != NULL) {
-               size_t new_rbufsize = cstream->rbufsize + len;
+               size_t new_rbufsize = len;
+               INSIST(cstream->rbuf != NULL);
+               new_rbufsize += isc_buffer_usedlength(cstream->rbuf);
                if (new_rbufsize <= MAX_DNS_MESSAGE_SIZE &&
                    new_rbufsize <= cstream->response_status.content_length)
                {
-                       memmove(cstream->rbuf + cstream->rbufsize, data, len);
-                       cstream->rbufsize = new_rbufsize;
+                       isc_buffer_putmem(cstream->rbuf, data, len);
                } else {
                        return (NGHTTP2_ERR_TEMPORAL_CALLBACK_FAILURE);
                }
@@ -572,12 +580,13 @@ static void
 call_unlink_cstream_readcb(http_cstream_t *cstream,
                           isc_nm_http_session_t *session,
                           isc_result_t result) {
+       isc_region_t read_data;
        REQUIRE(VALID_HTTP2_SESSION(session));
        REQUIRE(cstream != NULL);
        ISC_LIST_UNLINK(session->cstreams, cstream, link);
        INSIST(VALID_NMHANDLE(session->client_httphandle));
-       cstream->read_cb(session->client_httphandle, result,
-                        &(isc_region_t){ cstream->rbuf, cstream->rbufsize },
+       isc_buffer_usedregion(cstream->rbuf, &read_data);
+       cstream->read_cb(session->client_httphandle, result, &read_data,
                         cstream->read_cbarg);
        put_http_cstream(session->mctx, cstream);
 }
@@ -2760,10 +2769,10 @@ client_call_failed_read_cb(isc_result_t result,
                 * in such a case.
                 */
                if (cstream->read_cb != NULL) {
+                       isc_region_t read_data;
+                       isc_buffer_usedregion(cstream->rbuf, &read_data);
                        cstream->read_cb(session->client_httphandle, result,
-                                        &(isc_region_t){ cstream->rbuf,
-                                                         cstream->rbufsize },
-                                        cstream->read_cbarg);
+                                        &read_data, cstream->read_cbarg);
                }
 
                if (result != ISC_R_TIMEDOUT || cstream->read_cb == NULL ||