From: Stefan Eissing <stefan@eissing.org>
Date: Fri, 7 Mar 2025 10:34:40 +0000 (+0100)
Subject: quiche: do not iterate over multi handles
X-Git-Tag: curl-8_13_0~218
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=646ffb591a45b4c0573470f3cdb3060498506c73;p=thirdparty%2Fcurl.git

quiche: do not iterate over multi handles

Quiche needs to find easy handles to events. Do this by iterating
over the filters stream hash and lookup the easy handle on a match.

This O(+streams-in-filter) vs O(all easy handles), at least once
we fix the multi lookup to use a hash.

Closes #16607
---

diff --git a/lib/vquic/curl_quiche.c b/lib/vquic/curl_quiche.c
index 0c2bc3309e..ab09da1118 100644
--- a/lib/vquic/curl_quiche.c
+++ b/lib/vquic/curl_quiche.c
@@ -196,24 +196,66 @@ static void h3_stream_hash_free(curl_off_t id, void *stream)
   h3_stream_ctx_free((struct stream_ctx *)stream);
 }
 
-static void check_resumes(struct Curl_cfilter *cf,
-                          struct Curl_easy *data)
+typedef bool cf_quiche_svisit(struct Curl_cfilter *cf,
+                              struct Curl_easy *sdata,
+                              struct stream_ctx *stream,
+                              void *user_data);
+
+struct cf_quiche_visit_ctx {
+  struct Curl_cfilter *cf;
+  struct Curl_multi *multi;
+  cf_quiche_svisit *cb;
+  void *user_data;
+};
+
+static bool cf_quiche_stream_do(curl_off_t mid, void *val, void *user_data)
+{
+  struct cf_quiche_visit_ctx *vctx = user_data;
+  struct stream_ctx *stream = val;
+  struct Curl_easy *sdata = Curl_multi_get_handle(vctx->multi, mid);
+  if(sdata)
+    return vctx->cb(vctx->cf, sdata, stream, vctx->user_data);
+  return TRUE;
+}
+
+static void cf_quiche_for_all_streams(struct Curl_cfilter *cf,
+                                      struct Curl_multi *multi,
+                                      cf_quiche_svisit *do_cb,
+                                      void *user_data)
 {
   struct cf_quiche_ctx *ctx = cf->ctx;
-  struct Curl_llist_node *e;
+  struct cf_quiche_visit_ctx vctx;
+  vctx.cf = cf;
+  vctx.multi = multi;
+  vctx.cb = do_cb;
+  vctx.user_data = user_data;
+  Curl_hash_offt_visit(&ctx->streams, cf_quiche_stream_do, &vctx);
+}
 
-  DEBUGASSERT(data->multi);
-  for(e = Curl_llist_head(&data->multi->process); e; e = Curl_node_next(e)) {
-    struct Curl_easy *sdata = Curl_node_elem(e);
-    if(sdata->conn == data->conn) {
-      struct stream_ctx *stream = H3_STREAM_CTX(ctx, sdata);
-      if(stream && stream->quic_flow_blocked) {
-        stream->quic_flow_blocked = FALSE;
-        Curl_expire(data, 0, EXPIRE_RUN_NOW);
-        CURL_TRC_CF(data, cf, "[%"FMT_PRIu64"] unblock", stream->id);
-      }
-    }
+static bool cf_quiche_do_resume(struct Curl_cfilter *cf,
+                                struct Curl_easy *sdata,
+                                struct stream_ctx *stream,
+                                void *user_data)
+{
+  (void)user_data;
+  if(stream->quic_flow_blocked) {
+    stream->quic_flow_blocked = FALSE;
+    Curl_expire(sdata, 0, EXPIRE_RUN_NOW);
+    CURL_TRC_CF(sdata, cf, "[%"FMT_PRIu64"] unblock", stream->id);
   }
+  return TRUE;
+}
+
+static bool cf_quiche_do_expire(struct Curl_cfilter *cf,
+                                struct Curl_easy *sdata,
+                                struct stream_ctx *stream,
+                                void *user_data)
+{
+  (void)stream;
+  (void)user_data;
+  CURL_TRC_CF(sdata, cf, "conn closed, expire transfer");
+  Curl_expire(sdata, 0, EXPIRE_RUN_NOW);
+  return TRUE;
 }
 
 static CURLcode h3_data_setup(struct Curl_cfilter *cf,
@@ -285,52 +327,12 @@ static void h3_drain_stream(struct Curl_cfilter *cf,
   }
 }
 
-static struct Curl_easy *get_stream_easy(struct Curl_cfilter *cf,
-                                         struct Curl_easy *data,
-                                         curl_uint64_t stream_id,
-                                         struct stream_ctx **pstream)
-{
-  struct cf_quiche_ctx *ctx = cf->ctx;
-  struct stream_ctx *stream;
-
-  (void)cf;
-  stream = H3_STREAM_CTX(ctx, data);
-  if(stream && stream->id == stream_id) {
-    *pstream = stream;
-    return data;
-  }
-  else {
-    struct Curl_llist_node *e;
-    DEBUGASSERT(data->multi);
-    for(e = Curl_llist_head(&data->multi->process); e; e = Curl_node_next(e)) {
-      struct Curl_easy *sdata = Curl_node_elem(e);
-      if(sdata->conn != data->conn)
-        continue;
-      stream = H3_STREAM_CTX(ctx, sdata);
-      if(stream && stream->id == stream_id) {
-        *pstream = stream;
-        return sdata;
-      }
-    }
-  }
-  *pstream = NULL;
-  return NULL;
-}
-
 static void cf_quiche_expire_conn_closed(struct Curl_cfilter *cf,
                                          struct Curl_easy *data)
 {
-  struct Curl_llist_node *e;
-
   DEBUGASSERT(data->multi);
   CURL_TRC_CF(data, cf, "conn closed, expire all transfers");
-  for(e = Curl_llist_head(&data->multi->process); e; e = Curl_node_next(e)) {
-    struct Curl_easy *sdata = Curl_node_elem(e);
-    if(sdata == data || sdata->conn != data->conn)
-      continue;
-    CURL_TRC_CF(sdata, cf, "conn closed, expire transfer");
-    Curl_expire(sdata, 0, EXPIRE_RUN_NOW);
-  }
+  cf_quiche_for_all_streams(cf, data->multi, cf_quiche_do_expire, NULL);
 }
 
 /*
@@ -557,14 +559,48 @@ static CURLcode h3_process_event(struct Curl_cfilter *cf,
   return result;
 }
 
+static CURLcode cf_quiche_ev_process(struct Curl_cfilter *cf,
+                                     struct Curl_easy *data,
+                                     struct stream_ctx *stream,
+                                     quiche_h3_event *ev)
+{
+  CURLcode result = h3_process_event(cf, data, stream, ev);
+  h3_drain_stream(cf, data);
+  if(result)
+    CURL_TRC_CF(data, cf, "error processing event %s "
+                "for [%"FMT_PRIu64"] -> %d", cf_ev_name(ev),
+                stream->id, result);
+  return result;
+}
+
+struct cf_quich_disp_ctx {
+  curl_uint64_t stream_id;
+  struct Curl_cfilter *cf;
+  struct Curl_multi *multi;
+  quiche_h3_event *ev;
+  CURLcode result;
+};
+
+static bool cf_quiche_disp_event(curl_off_t mid, void *val, void *user_data)
+{
+  struct cf_quich_disp_ctx *dctx = user_data;
+  struct stream_ctx *stream = val;
+
+  if(stream->id == dctx->stream_id) {
+    struct Curl_easy *sdata = Curl_multi_get_handle(dctx->multi, mid);
+    if(sdata)
+      dctx->result = cf_quiche_ev_process(dctx->cf, sdata, stream, dctx->ev);
+    return FALSE; /* stop iterating */
+  }
+  return TRUE;
+}
+
 static CURLcode cf_poll_events(struct Curl_cfilter *cf,
                                struct Curl_easy *data)
 {
   struct cf_quiche_ctx *ctx = cf->ctx;
   struct stream_ctx *stream = NULL;
-  struct Curl_easy *sdata;
   quiche_h3_event *ev;
-  CURLcode result;
 
   /* Take in the events and distribute them to the transfers. */
   while(ctx->h3c) {
@@ -576,28 +612,27 @@ static CURLcode cf_poll_events(struct Curl_cfilter *cf,
       CURL_TRC_CF(data, cf, "error poll: %"FMT_PRId64, stream3_id);
       return CURLE_HTTP3;
     }
-
-    sdata = get_stream_easy(cf, data, stream3_id, &stream);
-    if(!sdata || !stream) {
-      CURL_TRC_CF(data, cf, "discard event %s for unknown [%"FMT_PRId64"]",
-                  cf_ev_name(ev), stream3_id);
-    }
     else {
-      result = h3_process_event(cf, sdata, stream, ev);
-      h3_drain_stream(cf, sdata);
-      if(result) {
-        CURL_TRC_CF(data, cf, "error processing event %s "
-                    "for [%"FMT_PRIu64"] -> %d", cf_ev_name(ev),
-                    stream3_id, result);
-        if(data == sdata) {
-          /* Only report this error to the caller if it is about the
-           * transfer we were called with. Otherwise we fail a transfer
-           * due to a problem in another one. */
-          quiche_h3_event_free(ev);
+      struct cf_quich_disp_ctx dctx;
+      dctx.stream_id = (curl_uint64_t)stream3_id;
+      dctx.cf = cf;
+      dctx.multi = data->multi;
+      dctx.ev = ev;
+      dctx.result = CURLE_OK;
+      stream = H3_STREAM_CTX(ctx, data);
+      if(stream && stream->id == dctx.stream_id) {
+        /* event for calling transfer */
+        CURLcode result = cf_quiche_ev_process(cf, data, stream, ev);
+        quiche_h3_event_free(ev);
+        if(result)
           return result;
-        }
       }
-      quiche_h3_event_free(ev);
+      else {
+        /* another transfer, do not return errors, as they are not for
+         * the calling transfer */
+        Curl_hash_offt_visit(&ctx->streams, cf_quiche_disp_event, &dctx);
+        quiche_h3_event_free(ev);
+      }
     }
   }
   return CURLE_OK;
@@ -686,7 +721,8 @@ static CURLcode cf_process_ingress(struct Curl_cfilter *cf,
   if(rctx.pkts > 0) {
     /* quiche digested ingress packets. It might have opened flow control
      * windows again. */
-    check_resumes(cf, data);
+    DEBUGASSERT(data->multi);
+    cf_quiche_for_all_streams(cf, data->multi, cf_quiche_do_resume, NULL);
   }
   return cf_poll_events(cf, data);
 }