MEDIUM: h2: detect the presence of the first settings frame
Instead of doing a special processing of the first SETTINGS frame, we
simply parse its header, check that it matches the expected frame type
and flags (ie no ACK), and switch to FRAME_P to parse it as any regular
frame. The regular frame parser will take care of decoding it.
diff --git a/src/mux_h2.c b/src/mux_h2.c
index d2d8574..71111eb 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -771,7 +771,41 @@
h2c->max_id = 0;
h2c->st0 = H2_CS_SETTINGS1;
}
- /* deal with SETTINGS here */
+
+ if (h2c->st0 == H2_CS_SETTINGS1) {
+ struct h2_fh hdr;
+
+ /* ensure that what is pending is a valid SETTINGS frame
+ * without an ACK.
+ */
+ if (!h2_get_frame_hdr(h2c->dbuf, &hdr)) {
+ /* RFC7540#3.5: a GOAWAY frame MAY be omitted */
+ if (h2c->st0 == H2_CS_ERROR)
+ h2c->st0 = H2_CS_ERROR2;
+ goto fail;
+ }
+
+ if (hdr.sid || hdr.ft != H2_FT_SETTINGS || hdr.ff & H2_F_SETTINGS_ACK) {
+ /* RFC7540#3.5: a GOAWAY frame MAY be omitted */
+ h2c_error(h2c, H2_ERR_PROTOCOL_ERROR);
+ h2c->st0 = H2_CS_ERROR2;
+ goto fail;
+ }
+
+ if ((int)hdr.len < 0 || (int)hdr.len > h2c->mfs) {
+ /* RFC7540#3.5: a GOAWAY frame MAY be omitted */
+ h2c_error(h2c, H2_ERR_FRAME_SIZE_ERROR);
+ h2c->st0 = H2_CS_ERROR2;
+ goto fail;
+ }
+
+ /* that's OK, switch to FRAME_P to process it */
+ h2c->dfl = hdr.len;
+ h2c->dsi = hdr.sid;
+ h2c->dft = hdr.ft;
+ h2c->dff = hdr.ff;
+ h2c->st0 = H2_CS_FRAME_P;
+ }
}
return;