MINOR: mux-h2: make h2c_decode_headers() return a status, not a count

This function used to return a byte count for the output produced, or
zero on failure. Not only this value is not used differently than a
boolean, but it prevents us from returning stream errors when a frame
cannot be extracted because it's too large, or from parsing a frame
and producing nothing on output.

This patch modifies its API to return <0 on errors, 0 on inability to
proceed, or >0 on success, irrelevant to the amount of output data.

diff --git a/src/mux_h2.c b/src/mux_h2.c
index af7af061ffc2e10b736274396c54937efc0d420d..2278a49189cad56363cfd1265d6369c17533a191 100644 (file)
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -1867,7 +1867,7 @@ static struct h2s *h2c_frt_handle_headers(struct h2c *h2c, struct h2s *h2s)
                goto conn_err;
        }
 
-       if (!h2c_decode_headers(h2c, &rxbuf, &flags))
+       if (h2c_decode_headers(h2c, &rxbuf, &flags) <= 0)
                goto out;
 
        if (h2c->st0 >= H2_CS_ERROR)
@@ -1954,7 +1954,7 @@ static struct h2s *h2c_bck_handle_headers(struct h2c *h2c, struct h2s *h2s)
        if (b_data(&h2c->dbuf) < h2c->dfl && !b_full(&h2c->dbuf))
                return NULL; // incomplete frame
 
-       if (!h2c_decode_headers(h2c, &h2s->rxbuf, &h2s->flags))
+       if (h2c_decode_headers(h2c, &h2s->rxbuf, &h2s->flags) <= 0)
                return NULL;
 
        if (h2c->st0 >= H2_CS_ERROR)
@@ -3155,10 +3155,11 @@ static void h2_shutw(struct conn_stream *cs, enum cs_shw_mode mode)
 }
 
 /* Decode the payload of a HEADERS frame and produce the equivalent HTTP/1 or
- * HTX request or response depending on the connection's side. Returns the
- * number of bytes emitted if > 0, or 0 if it couldn't proceed. May report
- * connection errors in h2c->errcode if the frame is non-decodable and not
- * recoverable.
+ * HTX request or response depending on the connection's side. Returns a
+ * positive value on success, a negative value on failure, or 0 if it couldn't
+ * proceed. May report connection errors in h2c->errcode if the frame is
+ * non-decodable and the connection unrecoverable. In absence of connection
+ * error when a failure is reported, the caller must assume a stream error.
  *
  * The function may fold CONTINUATION frames into the initial HEADERS frame
  * by removing padding and next frame header, then moving the CONTINUATION
@@ -3207,7 +3208,8 @@ static int h2c_decode_headers(struct h2c *h2c, struct buffer *rxbuf, uint32_t *f
        struct htx *htx = NULL;
        int flen; // header frame len
        int hole = 0;
-       int outlen = 0;
+       int ret = 0;
+       int outlen;
        int wrap;
        int try = 0;
 
@@ -3300,7 +3302,7 @@ next_frame:
 
        if (!h2_get_buf(h2c, rxbuf)) {
                h2c->flags |= H2_CF_DEM_SALLOC;
-               goto fail;
+               goto leave;
        }
 
        /* we can't retry a failed decompression operation so we must be very
@@ -3313,12 +3315,12 @@ next_frame:
                htx = htx_from_buf(rxbuf);
                if (!htx_is_empty(htx)) {
                        h2c->flags |= H2_CF_DEM_SFULL;
-                       goto fail;
+                       goto leave;
                }
        } else {
                if (b_data(rxbuf)) {
                        h2c->flags |= H2_CF_DEM_SFULL;
-                       goto fail;
+                       goto leave;
                }
 
                rxbuf->head = 0;
@@ -3369,8 +3371,11 @@ next_frame:
        if (htx && h2c->dff & H2_F_HEADERS_END_STREAM)
                htx_add_endof(htx, HTX_BLK_EOM);
 
+       /* success */
+       ret = 1;
+
  leave:
-       /* If there is a hole left and it's not a t the end, we are forced to
+       /* If there is a hole left and it's not at the end, we are forced to
         * move the remaining data over it.
         */
        if (hole) {
@@ -3383,15 +3388,16 @@ next_frame:
        if (b_full(&h2c->dbuf) && h2c->dfl > b_data(&h2c->dbuf)) {
                /* too large frames */
                h2c_error(h2c, H2_ERR_INTERNAL_ERROR);
-               goto fail;
+               ret = -1;
        }
 
        if (htx)
                htx_to_buf(htx, rxbuf);
        free_trash_chunk(copy);
-       return outlen;
+       return ret;
+
  fail:
-       outlen = 0;
+       ret = -1;
        goto leave;
 }