[Qemu-devel] [PATCH FYI 18/46] ui: convert VNC server to use QIOChannelWebsock

["Daniel P. Berrange" <berrange@redhat.com>]

Remove custom websock handling code from the VNC server and use
the QIOChannelWebsock class instead.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 ui/vnc-ws.c | 328 +++++-------------------------------------------------------
 ui/vnc-ws.h |  63 ------------
 ui/vnc.c    |  25 +----
 ui/vnc.h    |   4 -
 4 files changed, 30 insertions(+), 390 deletions(-)

diff --git a/ui/vnc-ws.c b/ui/vnc-ws.c
index 4863584..8018233 100644
--- a/ui/vnc-ws.c
+++ b/ui/vnc-ws.c
@@ -19,10 +19,7 @@
  */
 
 #include "vnc.h"
-#include "qemu/main-loop.h"
-#include "crypto/hash.h"
-
-static void vncws_handshake_read(VncState *vs);
+#include "io/channel-websock.h"
 
 static void vncws_tls_handshake_done(Object *source,
                                      Error *err,
@@ -34,6 +31,7 @@ static void vncws_tls_handshake_done(Object *source,
         VNC_DEBUG("Handshake failed %s\n", error_get_pretty(err));
         vnc_client_error(vs);
     } else {
+        VNC_DEBUG("TLS handshake complete, starting websocket handshake\n");
         vs->ioc_tag = qio_channel_add_watch(
             QIO_CHANNEL(vs->ioc), G_IO_IN, vncws_handshake_io, vs, NULL);
     }
@@ -79,38 +77,21 @@ gboolean vncws_tls_handshake_io(QIOChannel *ioc G_GNUC_UNUSED,
     return TRUE;
 }
 
-static void vncws_handshake_read(VncState *vs)
-{
-    uint8_t *handshake_end;
-    long ret;
-    /* Typical HTTP headers from novnc are 512 bytes, so limiting
-     * total header size to 4096 is easily enough. */
-    size_t want = 4096 - vs->ws_input.offset;
-    qio_buffer_reserve(&vs->ws_input, want);
-    ret = vnc_client_read_buf(vs, qio_buffer_end(&vs->ws_input), want);
 
-    if (!ret) {
-        if (vs->disconnecting) {
-            vnc_disconnect_finish(vs);
-        }
-        return;
-    }
-    vs->ws_input.offset += ret;
+static void vncws_handshake_done(Object *source,
+                                 Error *err,
+                                 gpointer user_data)
+{
+    VncState *vs = user_data;
 
-    handshake_end = (uint8_t *)g_strstr_len((char *)vs->ws_input.buffer,
-            vs->ws_input.offset, WS_HANDSHAKE_END);
-    if (handshake_end) {
-        if (vs->ioc_tag) {
-            g_source_remove(vs->ioc_tag);
-        }
+    if (err) {
+        VNC_DEBUG("Websock handshake failed %s\n", error_get_pretty(err));
+        vnc_client_error(vs);
+    } else {
+        VNC_DEBUG("Websock handshake complete, starting VNC protocol\n");
+        vnc_init_state(vs);
         vs->ioc_tag = qio_channel_add_watch(
             vs->ioc, G_IO_IN, vnc_client_io, vs, NULL);
-        vncws_process_handshake(vs, vs->ws_input.buffer, vs->ws_input.offset);
-        qio_buffer_advance(&vs->ws_input, handshake_end - vs->ws_input.buffer +
-                strlen(WS_HANDSHAKE_END));
-    } else if (vs->ws_input.offset >= 4096) {
-        VNC_DEBUG("End of headers not found in first 4096 bytes\n");
-        vnc_client_error(vs);
     }
 }
 
@@ -120,280 +101,23 @@ gboolean vncws_handshake_io(QIOChannel *ioc G_GNUC_UNUSED,
                             void *opaque)
 {
     VncState *vs = opaque;
-    vncws_handshake_read(vs);
-    return TRUE;
-}
-
-long vnc_client_read_ws(VncState *vs)
-{
-    int ret, err;
-    uint8_t *payload;
-    size_t payload_size, header_size;
-    VNC_DEBUG("Read websocket %p size %zd offset %zd\n", vs->ws_input.buffer,
-            vs->ws_input.capacity, vs->ws_input.offset);
-    qio_buffer_reserve(&vs->ws_input, 4096);
-    ret = vnc_client_read_buf(vs, qio_buffer_end(&vs->ws_input), 4096);
-    if (!ret) {
-        return 0;
-    }
-    vs->ws_input.offset += ret;
-
-    ret = 0;
-    /* consume as much of ws_input buffer as possible */
-    do {
-        if (vs->ws_payload_remain == 0) {
-            err = vncws_decode_frame_header(&vs->ws_input,
-                                            &header_size,
-                                            &vs->ws_payload_remain,
-                                            &vs->ws_payload_mask);
-            if (err <= 0) {
-                return err;
-            }
-
-            qio_buffer_advance(&vs->ws_input, header_size);
-        }
-        if (vs->ws_payload_remain != 0) {
-            err = vncws_decode_frame_payload(&vs->ws_input,
-                                             &vs->ws_payload_remain,
-                                             &vs->ws_payload_mask,
-                                             &payload,
-                                             &payload_size);
-            if (err < 0) {
-                return err;
-            }
-            if (err == 0) {
-                return ret;
-            }
-            ret += err;
-
-            qio_buffer_reserve(&vs->input, payload_size);
-            qio_buffer_append(&vs->input, payload, payload_size);
-
-            qio_buffer_advance(&vs->ws_input, payload_size);
-        }
-    } while (vs->ws_input.offset > 0);
-
-    return ret;
-}
-
-long vnc_client_write_ws(VncState *vs)
-{
-    long ret;
-    VNC_DEBUG("Write WS: Pending output %p size %zd offset %zd\n",
-              vs->output.buffer, vs->output.capacity, vs->output.offset);
-    vncws_encode_frame(&vs->ws_output, vs->output.buffer, vs->output.offset);
-    qio_buffer_reset(&vs->output);
-    ret = vnc_client_write_buf(vs, vs->ws_output.buffer, vs->ws_output.offset);
-    if (!ret) {
-        return 0;
-    }
-
-    qio_buffer_advance(&vs->ws_output, ret);
-
-    if (vs->ws_output.offset == 0) {
-        if (vs->ioc_tag) {
-            g_source_remove(vs->ioc_tag);
-        }
-        vs->ioc_tag = qio_channel_add_watch(
-            vs->ioc, G_IO_IN, vnc_client_io, vs, NULL);
-    }
-
-    return ret;
-}
-
-static char *vncws_extract_handshake_entry(const char *handshake,
-        size_t handshake_len, const char *name)
-{
-    char *begin, *end, *ret = NULL;
-    char *line = g_strdup_printf("%s%s: ", WS_HANDSHAKE_DELIM, name);
-    begin = g_strstr_len(handshake, handshake_len, line);
-    if (begin != NULL) {
-        begin += strlen(line);
-        end = g_strstr_len(begin, handshake_len - (begin - handshake),
-                WS_HANDSHAKE_DELIM);
-        if (end != NULL) {
-            ret = g_strndup(begin, end - begin);
-        }
-    }
-    g_free(line);
-    return ret;
-}
-
-static void vncws_send_handshake_response(VncState *vs, const char* key)
-{
-    char combined_key[WS_CLIENT_KEY_LEN + WS_GUID_LEN + 1];
-    char *accept = NULL, *response = NULL;
-    Error *err = NULL;
-
-    g_strlcpy(combined_key, key, WS_CLIENT_KEY_LEN + 1);
-    g_strlcat(combined_key, WS_GUID, WS_CLIENT_KEY_LEN + WS_GUID_LEN + 1);
-
-    /* hash and encode it */
-    if (qcrypto_hash_base64(QCRYPTO_HASH_ALG_SHA1,
-                            combined_key,
-                            WS_CLIENT_KEY_LEN + WS_GUID_LEN,
-                            &accept,
-                            &err) < 0) {
-        VNC_DEBUG("Hashing Websocket combined key failed %s\n",
-                  error_get_pretty(err));
-        error_free(err);
-        vnc_client_error(vs);
-        return;
-    }
-
-    response = g_strdup_printf(WS_HANDSHAKE, accept);
-    vnc_client_write_buf(vs, (const uint8_t *)response, strlen(response));
+    QIOChannelWebsock *wioc;
 
-    g_free(accept);
-    g_free(response);
-
-    vs->encode_ws = 1;
-    vnc_init_state(vs);
-}
-
-void vncws_process_handshake(VncState *vs, uint8_t *line, size_t size)
-{
-    char *protocols = vncws_extract_handshake_entry((const char *)line, size,
-            "Sec-WebSocket-Protocol");
-    char *version = vncws_extract_handshake_entry((const char *)line, size,
-            "Sec-WebSocket-Version");
-    char *key = vncws_extract_handshake_entry((const char *)line, size,
-            "Sec-WebSocket-Key");
-
-    if (protocols && version && key
-            && g_strrstr(protocols, "binary")
-            && !strcmp(version, WS_SUPPORTED_VERSION)
-            && strlen(key) == WS_CLIENT_KEY_LEN) {
-        vncws_send_handshake_response(vs, key);
-    } else {
-        VNC_DEBUG("Defective Websockets header or unsupported protocol\n");
-        vnc_client_error(vs);
-    }
-
-    g_free(protocols);
-    g_free(version);
-    g_free(key);
-}
-
-void vncws_encode_frame(QIOBuffer *output, const void *payload,
-                        const size_t payload_size)
-{
-    size_t header_size = 0;
-    unsigned char opcode = WS_OPCODE_BINARY_FRAME;
-    union {
-        char buf[WS_HEAD_MAX_LEN];
-        WsHeader ws;
-    } header;
-
-    if (!payload_size) {
-        return;
-    }
-
-    header.ws.b0 = 0x80 | (opcode & 0x0f);
-    if (payload_size <= 125) {
-        header.ws.b1 = (uint8_t)payload_size;
-        header_size = 2;
-    } else if (payload_size < 65536) {
-        header.ws.b1 = 0x7e;
-        header.ws.u.s16.l16 = cpu_to_be16((uint16_t)payload_size);
-        header_size = 4;
-    } else {
-        header.ws.b1 = 0x7f;
-        header.ws.u.s64.l64 = cpu_to_be64(payload_size);
-        header_size = 10;
-    }
-
-    qio_buffer_reserve(output, header_size + payload_size);
-    qio_buffer_append(output, header.buf, header_size);
-    qio_buffer_append(output, payload, payload_size);
-}
-
-int vncws_decode_frame_header(QIOBuffer *input,
-                              size_t *header_size,
-                              size_t *payload_remain,
-                              WsMask *payload_mask)
-{
-    unsigned char opcode = 0, fin = 0, has_mask = 0;
-    size_t payload_len;
-    WsHeader *header = (WsHeader *)input->buffer;
-
-    if (input->offset < WS_HEAD_MIN_LEN + 4) {
-        /* header not complete */
-        return 0;
-    }
-
-    fin = (header->b0 & 0x80) >> 7;
-    opcode = header->b0 & 0x0f;
-    has_mask = (header->b1 & 0x80) >> 7;
-    payload_len = header->b1 & 0x7f;
-
-    if (opcode == WS_OPCODE_CLOSE) {
-        /* disconnect */
-        return -1;
-    }
-
-    /* Websocket frame sanity check:
-     * * Websocket fragmentation is not supported.
-     * * All  websockets frames sent by a client have to be masked.
-     * * Only binary encoding is supported.
-     */
-    if (!fin || !has_mask || opcode != WS_OPCODE_BINARY_FRAME) {
-        VNC_DEBUG("Received faulty/unsupported Websocket frame\n");
-        return -2;
+    VNC_DEBUG("Websocket negotiate starting\n");
+    if (vs->ioc_tag) {
+        g_source_remove(vs->ioc_tag);
+        vs->ioc_tag = 0;
     }
 
-    if (payload_len < 126) {
-        *payload_remain = payload_len;
-        *header_size = 6;
-        *payload_mask = header->u.m;
-    } else if (payload_len == 126 && input->offset >= 8) {
-        *payload_remain = be16_to_cpu(header->u.s16.l16);
-        *header_size = 8;
-        *payload_mask = header->u.s16.m16;
-    } else if (payload_len == 127 && input->offset >= 14) {
-        *payload_remain = be64_to_cpu(header->u.s64.l64);
-        *header_size = 14;
-        *payload_mask = header->u.s64.m64;
-    } else {
-        /* header not complete */
-        return 0;
-    }
+    wioc = qio_channel_websock_new_server(vs->ioc);
 
-    return 1;
-}
-
-int vncws_decode_frame_payload(QIOBuffer *input,
-                               size_t *payload_remain, WsMask *payload_mask,
-                               uint8_t **payload, size_t *payload_size)
-{
-    size_t i;
-    uint32_t *payload32;
-
-    *payload = input->buffer;
-    /* If we aren't at the end of the payload, then drop
-     * off the last bytes, so we're always multiple of 4
-     * for purpose of unmasking, except at end of payload
-     */
-    if (input->offset < *payload_remain) {
-        *payload_size = input->offset - (input->offset % 4);
-    } else {
-        *payload_size = *payload_remain;
-    }
-    if (*payload_size == 0) {
-        return 0;
-    }
-    *payload_remain -= *payload_size;
+    object_unref(OBJECT(vs->ioc));
+    vs->ioc = QIO_CHANNEL(wioc);
 
-    /* unmask frame */
-    /* process 1 frame (32 bit op) */
-    payload32 = (uint32_t *)(*payload);
-    for (i = 0; i < *payload_size / 4; i++) {
-        payload32[i] ^= payload_mask->u;
-    }
-    /* process the remaining bytes (if any) */
-    for (i *= 4; i < *payload_size; i++) {
-        (*payload)[i] ^= payload_mask->c[i % 4];
-    }
+    qio_channel_websock_handshake(wioc,
+                                  vncws_handshake_done,
+                                  vs,
+                                  NULL);
 
-    return 1;
+    return TRUE;
 }
diff --git a/ui/vnc-ws.h b/ui/vnc-ws.h
index 21caaf3..652b6fc 100644
--- a/ui/vnc-ws.h
+++ b/ui/vnc-ws.h
@@ -21,74 +21,11 @@
 #ifndef __QEMU_UI_VNC_WS_H
 #define __QEMU_UI_VNC_WS_H
 
-#define B64LEN(__x) (((__x + 2) / 3) * 12 / 3)
-#define SHA1_DIGEST_LEN 20
-
-#define WS_ACCEPT_LEN (B64LEN(SHA1_DIGEST_LEN) + 1)
-#define WS_CLIENT_KEY_LEN 24
-#define WS_GUID "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
-#define WS_GUID_LEN strlen(WS_GUID)
-
-#define WS_HANDSHAKE "HTTP/1.1 101 Switching Protocols\r\n\
-Upgrade: websocket\r\n\
-Connection: Upgrade\r\n\
-Sec-WebSocket-Accept: %s\r\n\
-Sec-WebSocket-Protocol: binary\r\n\
-\r\n"
-#define WS_HANDSHAKE_DELIM "\r\n"
-#define WS_HANDSHAKE_END "\r\n\r\n"
-#define WS_SUPPORTED_VERSION "13"
-
-#define WS_HEAD_MIN_LEN sizeof(uint16_t)
-#define WS_HEAD_MAX_LEN (WS_HEAD_MIN_LEN + sizeof(uint64_t) + sizeof(uint32_t))
-
-typedef union WsMask {
-    char c[4];
-    uint32_t u;
-} WsMask;
-
-typedef struct QEMU_PACKED WsHeader {
-    unsigned char b0;
-    unsigned char b1;
-    union {
-        struct QEMU_PACKED {
-            uint16_t l16;
-            WsMask m16;
-        } s16;
-        struct QEMU_PACKED {
-            uint64_t l64;
-            WsMask m64;
-        } s64;
-        WsMask m;
-    } u;
-} WsHeader;
-
-enum {
-    WS_OPCODE_CONTINUATION = 0x0,
-    WS_OPCODE_TEXT_FRAME = 0x1,
-    WS_OPCODE_BINARY_FRAME = 0x2,
-    WS_OPCODE_CLOSE = 0x8,
-    WS_OPCODE_PING = 0x9,
-    WS_OPCODE_PONG = 0xA
-};
-
 gboolean vncws_tls_handshake_io(QIOChannel *ioc,
                                 GIOCondition condition,
                                 void *opaque);
 gboolean vncws_handshake_io(QIOChannel *ioc,
                             GIOCondition condition,
                             void *opaque);
-long vnc_client_write_ws(VncState *vs);
-long vnc_client_read_ws(VncState *vs);
-void vncws_process_handshake(VncState *vs, uint8_t *line, size_t size);
-void vncws_encode_frame(QIOBuffer *output, const void *payload,
-            const size_t payload_size);
-int vncws_decode_frame_header(QIOBuffer *input,
-                              size_t *header_size,
-                              size_t *payload_remain,
-                              WsMask *payload_mask);
-int vncws_decode_frame_payload(QIOBuffer *input,
-                               size_t *payload_remain, WsMask *payload_mask,
-                               uint8_t **payload, size_t *payload_size);
 
 #endif /* __QEMU_UI_VNC_WS_H */
diff --git a/ui/vnc.c b/ui/vnc.c
index 3fe5fed..59cd8a8 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -1154,8 +1154,6 @@ void vnc_disconnect_finish(VncState *vs)
 
     qio_buffer_free(&vs->input);
     qio_buffer_free(&vs->output);
-    qio_buffer_free(&vs->ws_input);
-    qio_buffer_free(&vs->ws_output);
 
     qapi_free_VncClientInfo(vs->info);
 
@@ -1310,11 +1308,7 @@ static void vnc_client_write_locked(VncState *vs)
     } else
 #endif /* CONFIG_VNC_SASL */
     {
-        if (vs->encode_ws) {
-            vnc_client_write_ws(vs);
-        } else {
-            vnc_client_write_plain(vs);
-        }
+        vnc_client_write_plain(vs);
     }
 }
 
@@ -1322,7 +1316,7 @@ static void vnc_client_write(VncState *vs)
 {
 
     vnc_lock_output(vs);
-    if (vs->output.offset || vs->ws_output.offset) {
+    if (vs->output.offset) {
         vnc_client_write_locked(vs);
     } else if (vs->ioc != NULL) {
         if (vs->ioc_tag) {
@@ -1409,18 +1403,7 @@ static void vnc_client_read(VncState *vs)
         ret = vnc_client_read_sasl(vs);
     else
 #endif /* CONFIG_VNC_SASL */
-        if (vs->encode_ws) {
-            ret = vnc_client_read_ws(vs);
-            if (ret == -1) {
-                vnc_disconnect_start(vs);
-                return;
-            } else if (ret == -2) {
-                vnc_client_error(vs);
-                return;
-            }
-        } else {
-            ret = vnc_client_read_plain(vs);
-        }
+        ret = vnc_client_read_plain(vs);
     if (!ret) {
         if (vs->disconnecting) {
             vnc_disconnect_finish(vs);
@@ -1510,7 +1493,7 @@ void vnc_write_u8(VncState *vs, uint8_t value)
 void vnc_flush(VncState *vs)
 {
     vnc_lock_output(vs);
-    if (vs->ioc != NULL && (vs->output.offset || vs->ws_output.offset)) {
+    if (vs->ioc != NULL && vs->output.offset) {
         vnc_client_write_locked(vs);
     }
     vnc_unlock_output(vs);
diff --git a/ui/vnc.h b/ui/vnc.h
index 65991c0..17f6455 100644
--- a/ui/vnc.h
+++ b/ui/vnc.h
@@ -293,10 +293,6 @@ struct VncState
 
     QIOBuffer output;
     QIOBuffer input;
-    QIOBuffer ws_input;
-    QIOBuffer ws_output;
-    size_t ws_payload_remain;
-    WsMask ws_payload_mask;
     /* current output mode information */
     VncWritePixels *write_pixels;
     PixelFormat client_pf;
-- 
2.4.3