[nginx] HTTP/2: reworked body reading to better match HTTP/1.x code.

Maxim Dounin mdounin at mdounin.ru
Sun Aug 29 21:00:53 UTC 2021


details:   https://hg.nginx.org/nginx/rev/0dcec8e5d50a
branches:  
changeset: 7908:0dcec8e5d50a
user:      Maxim Dounin <mdounin at mdounin.ru>
date:      Sun Aug 29 22:20:36 2021 +0300
description:
HTTP/2: reworked body reading to better match HTTP/1.x code.

In particular, now the code always uses a buffer limited by
client_body_buffer_size.  At the cost of an additional copy it
ensures that small DATA frames are not directly mapped to small
write() syscalls, but rather buffered in memory before writing.
Further, requests without Content-Length are no longer forced
to use temporary files.

diffstat:

 src/http/v2/ngx_http_v2.c |  186 +++++++++++++++++++++++++++------------------
 1 files changed, 110 insertions(+), 76 deletions(-)

diffs (236 lines):

diff -r 51f463301f86 -r 0dcec8e5d50a src/http/v2/ngx_http_v2.c
--- a/src/http/v2/ngx_http_v2.c	Sun Aug 29 22:20:34 2021 +0300
+++ b/src/http/v2/ngx_http_v2.c	Sun Aug 29 22:20:36 2021 +0300
@@ -4032,12 +4032,12 @@ ngx_http_v2_read_request_body(ngx_http_r
 
     len = r->headers_in.content_length_n;
 
+    if (len < 0 || len > (off_t) clcf->client_body_buffer_size) {
+        len = clcf->client_body_buffer_size;
+    }
+
     if (r->request_body_no_buffering && !stream->in_closed) {
 
-        if (len < 0 || len > (off_t) clcf->client_body_buffer_size) {
-            len = clcf->client_body_buffer_size;
-        }
-
         /*
          * We need a room to store data up to the stream's initial window size,
          * at least until this window will be exhausted.
@@ -4050,21 +4050,9 @@ ngx_http_v2_read_request_body(ngx_http_r
         if (len > NGX_HTTP_V2_MAX_WINDOW) {
             len = NGX_HTTP_V2_MAX_WINDOW;
         }
-
-        rb->buf = ngx_create_temp_buf(r->pool, (size_t) len);
-
-    } else if (len >= 0 && len <= (off_t) clcf->client_body_buffer_size
-               && !r->request_body_in_file_only)
-    {
-        rb->buf = ngx_create_temp_buf(r->pool, (size_t) len);
-
-    } else {
-        rb->buf = ngx_calloc_buf(r->pool);
-
-        if (rb->buf != NULL) {
-            rb->buf->sync = 1;
-        }
-    }
+    }
+
+    rb->buf = ngx_create_temp_buf(r->pool, (size_t) len);
 
     if (rb->buf == NULL) {
         stream->skip_data = 1;
@@ -4144,7 +4132,7 @@ static ngx_int_t
 ngx_http_v2_process_request_body(ngx_http_request_t *r, u_char *pos,
     size_t size, ngx_uint_t last)
 {
-    ngx_buf_t                 *buf;
+    size_t                     n;
     ngx_int_t                  rc;
     ngx_connection_t          *fc;
     ngx_http_request_body_t   *rb;
@@ -4152,79 +4140,125 @@ ngx_http_v2_process_request_body(ngx_htt
 
     fc = r->connection;
     rb = r->request_body;
-    buf = rb->buf;
 
     ngx_log_debug0(NGX_LOG_DEBUG_HTTP, fc->log, 0,
                    "http2 process request body");
 
-    if (size) {
-        if (buf->sync) {
-            buf->pos = buf->start = pos;
-            buf->last = buf->end = pos + size;
-
-            r->request_body_in_file_only = 1;
-
-        } else {
-            if (size > (size_t) (buf->end - buf->last)) {
-                ngx_log_error(NGX_LOG_INFO, fc->log, 0,
-                              "client intended to send body data "
-                              "larger than declared");
-
-                return NGX_HTTP_BAD_REQUEST;
+    if (size == 0 && !last) {
+        return NGX_OK;
+    }
+
+    for ( ;; ) {
+        for ( ;; ) {
+            if (rb->buf->last == rb->buf->end && size) {
+
+                if (r->request_body_no_buffering) {
+
+                    /* should never happen due to flow control */
+
+                    ngx_log_error(NGX_LOG_ALERT, fc->log, 0,
+                                  "no space in http2 body buffer");
+
+                    return NGX_HTTP_INTERNAL_SERVER_ERROR;
+                }
+
+                /* update chains */
+
+                ngx_log_error(NGX_LOG_DEBUG, fc->log, 0,
+                              "http2 body update chains");
+
+                rc = ngx_http_v2_filter_request_body(r);
+
+                if (rc != NGX_OK) {
+                    return rc;
+                }
+
+                if (rb->busy != NULL) {
+                    ngx_log_error(NGX_LOG_ALERT, fc->log, 0,
+                                  "busy buffers after request body flush");
+                    return NGX_HTTP_INTERNAL_SERVER_ERROR;
+                }
+
+                rb->buf->pos = rb->buf->start;
+                rb->buf->last = rb->buf->start;
+            }
+
+            /* copy body data to the buffer */
+
+            n = rb->buf->end - rb->buf->last;
+
+            if (n > size) {
+                n = size;
             }
 
-            buf->last = ngx_cpymem(buf->last, pos, size);
+            rb->buf->last = ngx_cpymem(rb->buf->last, pos, n);
+
+            ngx_log_debug1(NGX_LOG_DEBUG_HTTP, fc->log, 0,
+                           "http2 request body recv %uz", n);
+
+            pos += n;
+            size -= n;
+
+            if (size == 0 && last) {
+                rb->rest = 0;
+            }
+
+            if (r->request_body_no_buffering) {
+                break;
+            }
+
+            /* pass buffer to request body filter chain */
+
+            rc = ngx_http_v2_filter_request_body(r);
+
+            if (rc != NGX_OK) {
+                return rc;
+            }
+
+            if (rb->rest == 0) {
+                break;
+            }
+
+            if (size == 0) {
+                break;
+            }
         }
-    }
-
-    if (last) {
-        rb->rest = 0;
-
-        if (fc->read->timer_set) {
-            ngx_del_timer(fc->read);
+
+        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, fc->log, 0,
+                       "http2 request body rest %O", rb->rest);
+
+        if (rb->rest == 0) {
+            break;
         }
 
-        if (r->request_body_no_buffering) {
-            ngx_post_event(fc->read, &ngx_posted_events);
+        if (size == 0) {
+            clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
+            ngx_add_timer(fc->read, clcf->client_body_timeout);
+
+            if (r->request_body_no_buffering) {
+                ngx_post_event(fc->read, &ngx_posted_events);
+                return NGX_OK;
+            }
+
             return NGX_OK;
         }
-
-        rc = ngx_http_v2_filter_request_body(r);
-
-        if (rc != NGX_OK) {
-            return rc;
-        }
-
-        if (buf->sync) {
-            /* prevent reusing this buffer in the upstream module */
-            rb->buf = NULL;
-        }
-
-        if (r->headers_in.chunked) {
-            r->headers_in.content_length_n = rb->received;
-        }
-
-        r->read_event_handler = ngx_http_block_reading;
-        rb->post_handler(r);
-
-        return NGX_OK;
-    }
-
-    if (size == 0) {
-        return NGX_OK;
-    }
-
-    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
-    ngx_add_timer(fc->read, clcf->client_body_timeout);
+    }
+
+    if (fc->read->timer_set) {
+        ngx_del_timer(fc->read);
+    }
 
     if (r->request_body_no_buffering) {
         ngx_post_event(fc->read, &ngx_posted_events);
         return NGX_OK;
     }
 
-    if (buf->sync) {
-        return ngx_http_v2_filter_request_body(r);
-    }
+    if (r->headers_in.chunked) {
+        r->headers_in.content_length_n = rb->received;
+    }
+
+    r->read_event_handler = ngx_http_block_reading;
+    rb->post_handler(r);
 
     return NGX_OK;
 }


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