diff options
| -rw-r--r-- | server/resolv/async_resolv.c | 83 |
1 files changed, 82 insertions, 1 deletions
diff --git a/server/resolv/async_resolv.c b/server/resolv/async_resolv.c index 8455b575..5fd4084b 100644 --- a/server/resolv/async_resolv.c +++ b/server/resolv/async_resolv.c @@ -68,13 +68,18 @@ struct resolv_ctx { struct resolv_ctx *next; struct tevent_context *ev_ctx; - ares_channel channel; + /* List of file descriptors that are watched by tevent. */ struct fd_watch *fds; /* Time in milliseconds before canceling a DNS request */ int timeout; + + /* The timeout watcher periodically calls ares_process_fd() to check + * if our pending requests didn't timeout. */ + int pending_requests; + struct tevent_timer *timeout_watcher; }; struct resolv_ctx *context_list; @@ -121,6 +126,73 @@ fd_input_available(struct tevent_context *ev, struct tevent_fd *fde, ares_process_fd(watch->ctx->channel, watch->fd, watch->fd); } +static void +check_fd_timeouts(struct tevent_context *ev, struct tevent_timer *te, + struct timeval current_time, void *private_data); + +static void +add_timeout_timer(struct tevent_context *ev, struct resolv_ctx *ctx) +{ + struct timeval tv = { 0 }; + struct timeval *tvp; + + tvp = ares_timeout(ctx->channel, NULL, &tv); + + if (tvp == NULL) { + tvp = &tv; + } + + /* Enforce a minimum of 1 second. */ + if (tvp->tv_sec < 1) { + tv = tevent_timeval_current_ofs(1, 0); + } else { + tv = tevent_timeval_current_ofs(tvp->tv_sec, tvp->tv_usec); + } + + ctx->timeout_watcher = tevent_add_timer(ev, ctx, tv, check_fd_timeouts, + ctx); + if (ctx->timeout_watcher == NULL) { + DEBUG(1, ("Out of memory\n")); + } +} + +static void +check_fd_timeouts(struct tevent_context *ev, struct tevent_timer *te, + struct timeval current_time, void *private_data) +{ + struct resolv_ctx *ctx = private_data; + + DEBUG(9, ("Checking for DNS timeouts\n")); + ares_process_fd(ctx->channel, ARES_SOCKET_BAD, ARES_SOCKET_BAD); + add_timeout_timer(ev, ctx); +} + +static void +schedule_timeout_watcher(struct tevent_context *ev, struct resolv_ctx *ctx) +{ + ctx->pending_requests++; + if (ctx->timeout_watcher) { + return; + } + + DEBUG(9, ("Scheduling DNS timeout watcher\n")); + add_timeout_timer(ev, ctx); +} + +static void +unschedule_timeout_watcher(struct resolv_ctx *ctx) +{ + if (ctx->pending_requests <= 0) { + DEBUG(1, ("Pending DNS requests mismatch\n")); + return; + } + + ctx->pending_requests--; + if (ctx->pending_requests == 0) { + DEBUG(9, ("Unscheduling DNS timeout watcher\n")); + talloc_zfree(ctx->timeout_watcher); + } +} static void fd_event_add(struct resolv_ctx *ctx, int s); static void fd_event_write(struct resolv_ctx *ctx, int s); @@ -423,6 +495,7 @@ resolv_gethostbyname_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev, return NULL; } tevent_req_set_callback(subreq, ares_gethostbyname_wakeup, req); + schedule_timeout_watcher(ev, ctx); return req; } @@ -440,6 +513,8 @@ resolv_gethostbyname_done(void *arg, int status, int timeouts, struct hostent *h return; } + unschedule_timeout_watcher(state->resolv_ctx); + if (hostent != NULL) { state->hostent = resolv_copy_hostent(req, hostent); if (state->hostent == NULL) { @@ -621,6 +696,7 @@ resolv_getsrv_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev, return NULL; } tevent_req_set_callback(subreq, ares_getsrv_wakeup, req); + schedule_timeout_watcher(ev, ctx); return req; } @@ -640,6 +716,8 @@ resolv_getsrv_done(void *arg, int status, int timeouts, unsigned char *abuf, int return; } + unschedule_timeout_watcher(state->resolv_ctx); + state->status = status; state->timeouts = timeouts; @@ -821,6 +899,7 @@ resolv_gettxt_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev, return NULL; } tevent_req_set_callback(subreq, ares_gettxt_wakeup, req); + schedule_timeout_watcher(ev, ctx); return req; } @@ -840,6 +919,8 @@ resolv_gettxt_done(void *arg, int status, int timeouts, unsigned char *abuf, int return; } + unschedule_timeout_watcher(state->resolv_ctx); + state->status = status; state->timeouts = timeouts; |