daemon/session2: add special event for OS buffer depletion

For the future, when we need to account for this for e.g. QUIC, which
will need to handle this in the UDP case.

diff --git a/daemon/io.c b/daemon/io.c
index 6a72d0494d4753472e42a7747e5f14a84ed90b5f..86bd314e88ae358a6d8109b9b5c4098e3da34f09 100644 (file)
--- a/daemon/io.c
+++ b/daemon/io.c
@@ -165,15 +165,20 @@ static enum protolayer_event_cb_result pl_tcp_event_wrap(
                enum protolayer_event_type event, void **baton,
                struct session2 *session, void *sess_data)
 {
-       if (event == PROTOLAYER_EVENT_STATS_SEND_ERR) {
+       switch (event) {
+       case PROTOLAYER_EVENT_STATS_SEND_ERR:
                the_worker->stats.err_tcp += 1;
                return PROTOLAYER_EVENT_CONSUME;
-       } else if (event == PROTOLAYER_EVENT_STATS_QRY_OUT) {
+       case PROTOLAYER_EVENT_STATS_QRY_OUT:
                the_worker->stats.tcp += 1;
                return PROTOLAYER_EVENT_CONSUME;
+       case PROTOLAYER_EVENT_OS_BUFFER_FULL:
+               session2_force_close(session);
+               return PROTOLAYER_EVENT_CONSUME;
+       default:
+               return PROTOLAYER_EVENT_PROPAGATE;
        }
 
-       return PROTOLAYER_EVENT_PROPAGATE;
 }
 
 __attribute__((constructor))

diff --git a/daemon/session2.c b/daemon/session2.c
index da54beeeab4003b64197e9f85c2736f4dda8ac25..53f90bcdd14dd8b63055923cba21cc5bee819288 100644 (file)
--- a/daemon/session2.c
+++ b/daemon/session2.c
@@ -1235,7 +1235,7 @@ static void session2_event_wrap(struct session2 *s, enum protolayer_event_type e
        session2_transport_event(s, event, baton);
 }
 
-void session2_event_unwrap(struct session2 *s, ssize_t start_ix, enum protolayer_event_type event, void *baton)
+static void session2_event_unwrap(struct session2 *s, ssize_t start_ix, enum protolayer_event_type event, void *baton)
 {
        bool cont;
        const struct protolayer_grp *grp = &protolayer_grps[s->proto];
@@ -1256,8 +1256,9 @@ void session2_event_unwrap(struct session2 *s, ssize_t start_ix, enum protolayer
         *
         * TODO: This might be undesirable for cases with sub-sessions - the
         * current idea is for the layers managing sub-sessions to just return
-        * `false` on `event_unwrap`, but a more "automatic" mechanism may be
-        * added when this is relevant, to make it less error-prone. */
+        * `PROTOLAYER_EVENT_CONSUME` on `event_unwrap`, but a more "automatic"
+        * mechanism may be added when this is relevant, to make it less
+        * error-prone. */
        session2_event_wrap(s, event, baton);
 }
 
@@ -1442,8 +1443,10 @@ static int session2_transport_pushv(struct session2 *s,
                        } else {
                                int ret = uv_udp_try_send((uv_udp_t*)handle,
                                                (uv_buf_t *)iov, iovcnt, comm->comm_addr);
-                               if (ret == UV_EAGAIN)
+                               if (ret == UV_EAGAIN) {
                                        ret = kr_error(ENOBUFS);
+                                       session2_event(s, PROTOLAYER_EVENT_OS_BUFFER_FULL, NULL);
+                               }
 
                                if (false && ret == UV_EAGAIN) { // XXX: see uv_try_write() below
                                        uv_udp_send_t *req = malloc(sizeof(*req));
@@ -1469,7 +1472,7 @@ static int session2_transport_pushv(struct session2 *s,
                        //      We were missing any handling of partial write success, too.
                        if (ret == UV_EAGAIN || (ret >= 0 && ret != iovec_sum(iov, iovcnt))) {
                                ret = kr_error(ENOBUFS);
-                               session2_force_close(s);
+                               session2_event(s, PROTOLAYER_EVENT_OS_BUFFER_FULL, NULL);
                        }
 
                        if (false && ret == UV_EAGAIN) {

diff --git a/daemon/session2.h b/daemon/session2.h
index dc602cca0411a49499d3bb47de2f116b3f55b438..604c43a1d2944067163b75f414380a975319352c 100644 (file)
--- a/daemon/session2.h
+++ b/daemon/session2.h
@@ -312,23 +312,31 @@ typedef void (*protolayer_finished_cb)(int status, struct session2 *session,
  * Event types are used to distinguish different events that can be passed to
  * sessions using `session2_event()`. */
 #define PROTOLAYER_EVENT_MAP(XX) \
-       XX(CLOSE) /**< Sending this event closes the session gracefully -
-                  * i.e. layers add their standard disconnection
-                  * ceremony (e.g. `gnutls_bye()`). */\
-       XX(FORCE_CLOSE) /**< Sending this event closes the session forcefully -
-                        * i.e. layers SHOULD NOT add any disconnection
-                        * ceremony, if avoidable. */\
-       XX(CONNECT_TIMEOUT) /**< Signal that a connection could not be
-                            * established due to a timeout. */\
-       XX(GENERAL_TIMEOUT) /**< Signal that a general application-defined
-                            * timeout has occurred. */\
-       XX(CONNECT) /**< Signal that a connection has been established. */\
-       XX(CONNECT_FAIL) /**< Signal that a connection could not have been
-                         * established. */\
-       XX(MALFORMED) /**< Signal that a malformed request has been received. */\
-       XX(DISCONNECT) /**< Signal that a connection has ended. */\
-       XX(STATS_SEND_ERR) /**< Failed task send - update stats. */\
-       XX(STATS_QRY_OUT) /**< Outgoing query submission - update stats. */
+       /** Closes the session gracefully - i.e. layers add their standard
+        * disconnection ceremony (e.g. `gnutls_bye()`). */\
+       XX(CLOSE) \
+       /** Closes the session forcefully - i.e. layers SHOULD NOT add any
+        * disconnection ceremony, if avoidable. */\
+       XX(FORCE_CLOSE) \
+       /** Signal that a connection could not be established due to a timeout. */\
+       XX(CONNECT_TIMEOUT) \
+       /** Signal that a general application-defined timeout has occurred. */\
+       XX(GENERAL_TIMEOUT) \
+       /** Signal that a connection has been established. */\
+       XX(CONNECT) \
+       /** Signal that a connection could not have been established. */\
+       XX(CONNECT_FAIL) \
+       /** Signal that a malformed request has been received. */\
+       XX(MALFORMED) \
+       /** Signal that a connection has ended. */\
+       XX(DISCONNECT) \
+       /** Failed task send - update stats. */\
+       XX(STATS_SEND_ERR) \
+       /** Outgoing query submission - update stats. */\
+       XX(STATS_QRY_OUT) \
+       /** OS buffers are full, so not sending any more data. */\
+       XX(OS_BUFFER_FULL) \
+       //
 
 /** Event type, to be interpreted by a layer. */
 enum protolayer_event_type {