auto import from //depot/cupcake/@135843

1 files changed, 1125 insertions, 0 deletions

diff --git a/proxy/proxy_http_rewriter.c b/proxy/proxy_http_rewriter.c
new file mode 100644
index 0000000..812bf9c
--- /dev/null
+++ b/proxy/proxy_http_rewriter.c
@@ -0,0 +1,1125 @@
+/* Copyright (C) 2007-2008 The Android Open Source Project
+**
+** This software is licensed under the terms of the GNU General Public
+** License version 2, as published by the Free Software Foundation, and
+** may be copied, distributed, and modified under those terms.
+**
+** This program is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+** GNU General Public License for more details.
+*/
+#include "proxy_http_int.h"
+#include <stdio.h>
+#include <string.h>
+#include "qemu-common.h"
+#include "android/utils/system.h"  /* strsep */
+
+/* this implements a transparent HTTP rewriting proxy
+ *
+ * this is needed because the HTTP spec mandates that
+ * any query made to a proxy uses an absolute URI as
+ * in:
+ *
+ *    GET http://www.example.com/index.html HTTP/1.1
+ *
+ * while the Android browser will think it's talking to
+ * a normal web server and will issue a:
+ *
+ *    GET /index.html HTTP/1.1
+ *    Host: www.example.com
+ *
+ * what we do here is thus the following:
+ *
+ * - read the request header
+ * - rewrite the request's URI to use absolute URI
+ * - send the rewritten header to the proxy
+ * - then read the rest of the request, and tunnel it to the
+ *   proxy as well
+ * - read the answer as-is and send it back to the system
+ *
+ * this sounds all easy, but the rules for computing the
+ * sizes of HTTP Message Bodies makes the implementation
+ * a *bit* funky.
+ */
+
+/* define D_ACTIVE to 1 to dump additionnal debugging
+ * info when -debug-proxy is used. These are only needed
+ * when debugging the proxy code.
+ */
+#define  D_ACTIVE  1
+
+#if D_ACTIVE
+#  define  D(...)   PROXY_LOG(__VA_ARGS__)
+#else
+#  define  D(...)   ((void)0)
+#endif
+
+
+/** *************************************************************
+ **
+ **   HTTP HEADERS
+ **
+ **/
+
+typedef struct HttpHeader {
+    struct HttpHeader*  next;
+    const char*         key;
+    const char*         value;
+} HttpHeader;
+
+static void
+http_header_free( HttpHeader*  h )
+{
+    if (h) {
+        qemu_free((char*)h->value);
+        qemu_free(h);
+    }
+}
+
+static int
+http_header_append( HttpHeader*  h, const char*  value )
+{
+    int    old = strlen(h->value);
+    int    new = strlen(value);
+    char*  s   = realloc((char*)h->value, old+new+1);
+    if (s == NULL)
+        return -1;
+    memcpy(s + old, value, new+1);
+    h->value = (const char*)s;
+    return 0;
+}
+
+static HttpHeader*
+http_header_alloc( const char*  key, const char*  value )
+{
+    int          len = strlen(key)+1;
+    HttpHeader*  h   = malloc(sizeof(*h) + len+1);
+    if (h) {
+        h->next  = NULL;
+        h->key   = (const char*)(h+1);
+        memcpy( (char*)h->key, key, len );
+        h->value = qemu_strdup(value);
+    }
+    return h;
+}
+
+typedef struct {
+    HttpHeader*   first;
+    HttpHeader*   last;
+} HttpHeaderList;
+
+static void
+http_header_list_init( HttpHeaderList*  l )
+{
+    l->first = l->last = NULL;
+}
+
+static void
+http_header_list_done( HttpHeaderList*  l )
+{
+    while (l->first) {
+        HttpHeader*  h = l->first;
+        l->first = h->next;
+        http_header_free(h);
+    }
+    l->last = NULL;
+}
+
+static void
+http_header_list_add( HttpHeaderList*  l,
+                      HttpHeader*      h )
+{
+    if (!l->first) {
+        l->first = h;
+    } else {
+        l->last->next = h;
+    }
+    h->next = NULL;
+    l->last = h;
+}
+
+static const char*
+http_header_list_find( HttpHeaderList*  l,
+                       const char*      key )
+{
+    HttpHeader*  h;
+    for (h = l->first; h; h = h->next)
+        if (!strcasecmp(h->key, key))
+            return h->value;
+
+    return NULL;
+}
+
+/** *************************************************************
+ **
+ **   HTTP REQUEST AND REPLY
+ **
+ **/
+
+typedef enum {
+    HTTP_REQUEST_UNSUPPORTED = 0,
+    HTTP_REQUEST_GET,
+    HTTP_REQUEST_HEAD,
+    HTTP_REQUEST_POST,
+    HTTP_REQUEST_PUT,
+    HTTP_REQUEST_DELETE,
+} HttpRequestType;
+
+typedef struct {
+    HttpRequestType   req_type;
+    char*             req_method;
+    char*             req_uri;
+    char*             req_version;
+    char*             rep_version;
+    int               rep_code;
+    char*             rep_readable;
+    HttpHeaderList    headers[1];
+} HttpRequest;
+
+
+static HttpRequest*
+http_request_alloc( const char*      method,
+                    const char*      uri,
+                    const char*      version )
+{
+    HttpRequest*  r = malloc(sizeof(*r));
+
+    r->req_method   = qemu_strdup(method);
+    r->req_uri      = qemu_strdup(uri);
+    r->req_version  = qemu_strdup(version);
+    r->rep_version  = NULL;
+    r->rep_code     = -1;
+    r->rep_readable = NULL;
+
+    if (!strcmp(method,"GET")) {
+        r->req_type = HTTP_REQUEST_GET;
+    } else if (!strcmp(method,"POST")) {
+        r->req_type = HTTP_REQUEST_POST;
+    } else if (!strcmp(method,"HEAD")) {
+        r->req_type = HTTP_REQUEST_HEAD;
+    } else if (!strcmp(method,"PUT")) {
+        r->req_type = HTTP_REQUEST_PUT;
+    } else if (!strcmp(method,"DELETE")) {
+        r->req_type = HTTP_REQUEST_DELETE;
+    } else
+        r->req_type = HTTP_REQUEST_UNSUPPORTED;
+
+    http_header_list_init(r->headers);
+    return r;
+}
+
+static void
+http_request_replace_uri( HttpRequest*  r,
+                          const char*   uri )
+{
+    const char*  old = r->req_uri;
+    r->req_uri = qemu_strdup(uri);
+    qemu_free((char*)old);
+}
+
+static void
+http_request_free( HttpRequest*  r )
+{
+    if (r) {
+        http_header_list_done(r->headers);
+
+        qemu_free(r->req_method);
+        qemu_free(r->req_uri);
+        qemu_free(r->req_version);
+        qemu_free(r->rep_version);
+        qemu_free(r->rep_readable);
+        qemu_free(r);
+    }
+}
+
+static char*
+http_request_find_header( HttpRequest*  r,
+                          const char*   key )
+{
+    return (char*)http_header_list_find(r->headers, key);
+}
+
+
+static int
+http_request_add_header( HttpRequest*  r,
+                         const char*   key,
+                         const char*   value )
+{
+    HttpHeader*  h = http_header_alloc(key,value);
+    if (h) {
+        http_header_list_add(r->headers, h);
+        return 0;
+    }
+    return -1;
+}
+
+static int
+http_request_add_to_last_header( HttpRequest*  r,
+                                 const char*   line )
+{
+    if (r->headers->last) {
+        return http_header_append( r->headers->last, line );
+    } else {
+        return -1;
+    }
+}
+
+static int
+http_request_set_reply( HttpRequest*  r,
+                        const char*   version,
+                        const char*   code,
+                        const char*   readable )
+{
+    if (strcmp(version,"HTTP/1.0") && strcmp(version,"HTTP/1.1")) {
+        PROXY_LOG("%s: bad reply protocol: %s", __FUNCTION__, version);
+        return -1;
+    }
+    r->rep_code = atoi(code);
+    if (r->rep_code == 0) {
+        PROXY_LOG("%s: bad reply code: %d", __FUNCTION__, code);
+        return -1;
+    }
+
+    r->rep_version  = qemu_strdup(version);
+    r->rep_readable = qemu_strdup(readable);
+
+    /* reset the list of headers */
+    http_header_list_done(r->headers);
+    return 0;
+}
+
+/** *************************************************************
+ **
+ **   REWRITER CONNECTION
+ **
+ **/
+
+typedef enum {
+    STATE_CONNECTING = 0,
+    STATE_CREATE_SOCKET_PAIR,
+    STATE_REQUEST_FIRST_LINE,
+    STATE_REQUEST_HEADERS,
+    STATE_REQUEST_SEND,
+    STATE_REQUEST_BODY,
+    STATE_REPLY_FIRST_LINE,
+    STATE_REPLY_HEADERS,
+    STATE_REPLY_SEND,
+    STATE_REPLY_BODY,
+} ConnectionState;
+
+/* root->socket is connected to the proxy server. while
+ * slirp_fd is connected to the slirp code through a
+ * socket_pair() we created for this specific purpose.
+ */
+
+typedef enum {
+    BODY_NONE = 0,
+    BODY_KNOWN_LENGTH,
+    BODY_UNTIL_CLOSE,
+    BODY_CHUNKED,
+    BODY_MODE_MAX
+} BodyMode;
+
+static const char* const  body_mode_str[BODY_MODE_MAX] = {
+    "NONE", "KNOWN_LENGTH", "UNTIL_CLOSE", "CHUNKED"
+};
+
+typedef struct {
+    ProxyConnection   root[1];
+    int               slirp_fd;
+    ConnectionState   state;
+    HttpRequest*      request;
+    BodyMode          body_mode;
+    int64_t           body_length;
+    int64_t           body_total;
+    int64_t           body_sent;
+    int64_t           chunk_length;
+    int64_t           chunk_total;
+    char              body_has_data;
+    char              body_is_full;
+    char              body_is_closed;
+    char              parse_chunk_header;
+    char              parse_chunk_trailer;
+} RewriteConnection;
+
+
+static void
+rewrite_connection_free( ProxyConnection*  root )
+{
+    RewriteConnection*  conn = (RewriteConnection*)root;
+
+    if (conn->slirp_fd >= 0) {
+        socket_close(conn->slirp_fd);
+        conn->slirp_fd = -1;
+    }
+    http_request_free(conn->request);
+    proxy_connection_done(root);
+    qemu_free(conn);
+}
+
+
+static int
+rewrite_connection_init( RewriteConnection*   conn )
+{
+    HttpService*      service = (HttpService*) conn->root->service;
+    ProxyConnection*  root    = conn->root;
+
+    conn->slirp_fd = -1;
+    conn->state    = STATE_CONNECTING;
+
+    if (socket_connect( root->socket, &service->server_addr ) < 0) {
+        if (errno == EINPROGRESS || errno == EWOULDBLOCK) {
+            PROXY_LOG("%s: connecting", conn->root->name);
+        }
+        else {
+            PROXY_LOG("%s: cannot connect to proxy: %s", root->name, errno_str);
+            return -1;
+        }
+    }
+    else {
+        PROXY_LOG("%s: immediate connection", root->name);
+        conn->state = STATE_CREATE_SOCKET_PAIR;
+    }
+    return 0;
+}
+
+static int
+rewrite_connection_create_sockets( RewriteConnection*  conn )
+{
+    /* immediate connection to the proxy. now create a socket
+        * pair and send a 'success' event to slirp */
+    int               slirp_1;
+    ProxyConnection*  root = conn->root;
+
+    if (socket_pair( &slirp_1, &conn->slirp_fd ) < 0) {
+        PROXY_LOG("%s: coult not create socket pair: %s",
+                    root->name, errno_str);
+        return -1;
+    }
+
+    root->ev_func( root->ev_opaque, slirp_1, PROXY_EVENT_CONNECTED );
+    conn->state = STATE_REQUEST_FIRST_LINE;
+    return 0;
+}
+
+
+/* read the first line of a given HTTP request. returns -1/0/+1 */
+static DataStatus
+rewrite_connection_read_request( RewriteConnection*  conn )
+{
+    ProxyConnection*  root = conn->root;
+    DataStatus        ret;
+
+    ret = proxy_connection_receive_line(root, conn->slirp_fd);
+    if (ret == DATA_COMPLETED) {
+        /* now parse the first line to see if we can handle it */
+        char*  line   = root->str->s;
+        char*  method;
+        char*  uri;
+        char*  version;
+        char*  p = line;
+
+        method = strsep(&p, " ");
+        if (p == NULL) {
+            PROXY_LOG("%s: can't parse method in '%'", 
+                      root->name, line);
+            return DATA_ERROR;
+        }
+        uri = strsep(&p, " ");
+        if (p == NULL) {
+            PROXY_LOG( "%s: can't parse URI in '%s'",
+                       root->name, line);
+            return DATA_ERROR;
+        }
+        version = strsep(&p, " ");
+        if (p != NULL) {
+            PROXY_LOG( "%s: extra data after version in '%s'",
+                       root->name, line);
+            return DATA_ERROR;
+        }
+        if (conn->request)
+            http_request_free(conn->request);
+
+        conn->request = http_request_alloc( method, uri, version );
+        if (!conn->request)
+            return DATA_ERROR;
+
+        proxy_connection_rewind(root);
+    }
+    return ret;
+}
+
+
+static DataStatus
+rewrite_connection_read_reply( RewriteConnection*  conn )
+{
+    ProxyConnection*  root = conn->root;
+    DataStatus        ret;
+
+    ret = proxy_connection_receive_line( root, root->socket );
+    if (ret == DATA_COMPLETED) {
+        HttpRequest*  request = conn->request;
+
+        char*  line = stralloc_cstr( root->str );
+        char*  p = line;
+        char*  protocol;
+        char*  number;
+        char*  readable;
+
+        protocol = strsep(&p, " ");
+        if (p == NULL) {
+            PROXY_LOG("%s: can't parse response protocol: '%s'",
+                      root->name, line);
+            return DATA_ERROR;
+        }
+        number = strsep(&p, " ");
+        if (p == NULL) {
+            PROXY_LOG("%s: can't parse response number: '%s'",
+                      root->name, line);
+            return DATA_ERROR;
+        }
+        readable = p;
+
+        if (http_request_set_reply(request, protocol, number, readable) < 0)
+            return DATA_ERROR;
+
+        proxy_connection_rewind(root);
+    }
+    return ret;
+}
+
+
+static DataStatus
+rewrite_connection_read_headers( RewriteConnection*   conn,
+                                 int                  fd )
+{
+    int               ret;
+    ProxyConnection*  root = conn->root;
+
+    for (;;) {
+        char*        line;
+        stralloc_t*  str = root->str;
+
+        ret = proxy_connection_receive_line(root, fd);
+        if (ret != DATA_COMPLETED)
+            break;
+
+        str->n = 0;
+        line   = str->s;
+
+        if (line[0] == 0) {
+            /* an empty line means the end of headers */
+            ret = 1;
+            break;
+        }
+
+        /* it this a continuation ? */
+        if (line[0] == ' ' || line[0] == '\t') {
+            ret = http_request_add_to_last_header( conn->request, line );
+        }
+        else {
+            char*  key;
+            char*  value;
+
+            value = line;
+            key   = strsep(&value, ":");
+            if (value == NULL) {
+                PROXY_LOG("%s: can't parse header '%s'", root->name, line);
+                ret = -1;
+                break;
+            }
+            value += strspn(value, " ");
+            if (http_request_add_header(conn->request, key, value) < 0)
+                ret = -1;
+        }
+        if (ret == DATA_ERROR)
+            break;
+    }
+    return ret;
+}
+
+static int
+rewrite_connection_rewrite_request( RewriteConnection*  conn )
+{
+    ProxyConnection* root    = conn->root;
+    HttpService*     service = (HttpService*) root->service;
+    HttpRequest*     r       = conn->request;
+    stralloc_t*      str     = root->str;
+    HttpHeader*      h;
+
+    proxy_connection_rewind(conn->root);
+
+    /* only rewrite the URI if it is not absolute */
+    if (r->req_uri[0] == '/') {
+        char*  host = http_request_find_header(r, "Host");
+        if (host == NULL) {
+            PROXY_LOG("%s: uh oh, not Host: in request ?", root->name);
+        } else {
+            /* now create new URI */
+            stralloc_add_str(str, "http://");
+            stralloc_add_str(str, host);
+            stralloc_add_str(str, r->req_uri);
+            http_request_replace_uri(r, stralloc_cstr(str));
+            proxy_connection_rewind(root);
+        }
+    }
+
+    stralloc_format( str, "%s %s %s\r\n", r->req_method, r->req_uri, r->req_version );
+    for (h = r->headers->first; h; h = h->next) {
+        stralloc_add_format( str, "%s: %s\r\n", h->key, h->value );
+    }
+    /* add the service's footer - includes final \r\n */
+    stralloc_add_bytes( str, service->footer, service->footer_len );
+
+    return 0;
+}
+
+static int
+rewrite_connection_rewrite_reply( RewriteConnection*  conn )
+{
+    HttpRequest*     r    = conn->request;
+    ProxyConnection* root = conn->root;
+    stralloc_t*      str  = root->str;
+    HttpHeader*      h;
+
+    proxy_connection_rewind(root);
+    stralloc_format(str, "%s %d %s\r\n", r->rep_version, r->rep_code, r->rep_readable);
+    for (h = r->headers->first; h; h = h->next) {
+        stralloc_add_format(str, "%s: %s\r\n", h->key, h->value);
+    }
+    stralloc_add_str(str, "\r\n");
+
+    return 0;
+}
+
+
+static int
+rewrite_connection_get_body_length( RewriteConnection*  conn,
+                                    int                 is_request )
+{
+    HttpRequest*      r    = conn->request;
+    ProxyConnection*  root = conn->root;
+    char*             content_length;
+    char*             transfer_encoding;
+
+    conn->body_mode      = BODY_NONE;
+    conn->body_length    = 0;
+    conn->body_total     = 0;
+    conn->body_sent      = 0;
+    conn->body_is_closed = 0;
+    conn->body_is_full   = 0;
+    conn->body_has_data  = 0;
+
+    proxy_connection_rewind(root);
+
+    if (is_request) {
+        /* only POST and PUT should have a body */
+        if (r->req_type != HTTP_REQUEST_POST &&
+            r->req_type != HTTP_REQUEST_PUT)
+        {
+            return 0;
+        }
+    } else {
+        /* HTTP 1.1 Section 4.3 Message Body states that HEAD requests must not have
+        * a message body, as well as any 1xx, 204 and 304 replies */
+        if (r->req_type == HTTP_REQUEST_HEAD || r->rep_code/100 == 1 ||
+            r->rep_code == 204 || r->rep_code == 304)
+            return 0;
+    }
+
+    content_length = http_request_find_header(r, "Content-Length");
+    if (content_length != NULL) {
+        char*    end;
+        int64_t  body_len = strtoll( content_length, &end, 10 );
+        if (*end != '\0' || *content_length == '\0' || body_len < 0) {
+            PROXY_LOG("%s: bad content length: %s", root->name, content_length);
+            return DATA_ERROR;
+        }
+        if (body_len > 0) {
+            conn->body_mode   = BODY_KNOWN_LENGTH;
+            conn->body_length = body_len;
+        }
+    } else {
+        char*  connection = http_request_find_header(r, "Proxy-Connection");
+
+        if (!connection)
+            connection = http_request_find_header(r, "Connection");
+
+        if (!connection || strcasecmp(connection, "Close")) {
+            /* hum, we can't support this at all */
+            PROXY_LOG("%s: can't determine content length, and client wants"
+                        " to keep connection opened",
+                        root->name);
+            return -1;
+        }
+        /* a negative value means that the data ends when the client
+         * disconnects the connection.
+         */
+        conn->body_mode = BODY_UNTIL_CLOSE;
+    }
+    transfer_encoding = http_request_find_header(r, "Transfer-Encoding");
+    if (transfer_encoding && !strcasecmp(transfer_encoding, "Chunked")) {
+        conn->body_mode           = BODY_CHUNKED;
+        conn->parse_chunk_header  = 0;
+        conn->parse_chunk_trailer = 0;
+        conn->chunk_length        = -1;
+        conn->chunk_total         = 0;
+    }
+    D("%s: body_length=%lld body_mode=%s",
+      root->name, conn->body_length, 
+      body_mode_str[conn->body_mode]);
+
+    proxy_connection_rewind(root);
+    return 0;
+}
+
+#define  MAX_BODY_BUFFER  65536
+
+static DataStatus
+rewrite_connection_read_body( RewriteConnection*  conn, int  fd )
+{
+    ProxyConnection*  root   = conn->root;
+    stralloc_t*       str    = root->str;
+    int               wanted = 0, current, avail;
+    DataStatus        ret;
+
+    if (conn->body_is_closed) {
+        return DATA_NEED_MORE;
+    }
+
+    /* first, determine how many bytes we want to read. */
+    switch (conn->body_mode) {
+    case BODY_NONE:
+        D("%s: INTERNAL ERROR: SHOULDN'T BE THERE", root->name);
+        return DATA_COMPLETED;
+
+    case BODY_KNOWN_LENGTH:
+        {
+            if (conn->body_length == 0)
+                return DATA_COMPLETED;
+
+            if (conn->body_length > MAX_BODY_BUFFER)
+                wanted = MAX_BODY_BUFFER;
+            else
+                wanted = (int)conn->body_length;
+        }
+        break;
+
+    case BODY_UNTIL_CLOSE:
+        wanted = MAX_BODY_BUFFER;
+        break;
+
+    case BODY_CHUNKED:
+        if (conn->chunk_length < 0) {
+            /* chunk_length < 0 means we need to read a chunk header */
+            /* ensure that 'str' is flushed before doing this */
+            if (!conn->parse_chunk_header) {
+                if (conn->body_has_data)
+                    return DATA_NEED_MORE;
+                D("%s: waiting chunk header", root->name);
+                conn->parse_chunk_header = 1;
+            }
+            ret = proxy_connection_receive_line(root, fd);
+            if (ret == DATA_COMPLETED) {
+                char*      line = str->s;
+                char*      end;
+                long long  length;
+
+                length = strtoll(line, &end, 16);
+                if (line[0] == ' ' || (end[0] != '\0' && end[0] != ';')) {
+                    PROXY_LOG("%s: invalid chunk header: %s",
+                              root->name, line);
+                    return DATA_ERROR;
+                }
+                if (length < 0) {
+                    PROXY_LOG("%s: invalid chunk length %lld",
+                              root->name, length);
+                    return DATA_ERROR;
+                }
+                conn->chunk_length = length;
+                conn->chunk_total  = 0;
+                if (length == 0) {
+                    /* the last chunk, no we need to add the trailer */
+                    conn->parse_chunk_trailer = 0;
+                }
+                conn->parse_chunk_header = 0;
+            }
+        }
+
+        if (conn->chunk_length == 0) {
+            /* chunk_length == 0 means we're reading the chunk trailer */
+            /* ensure that 'str' is flushed before reading the trailer */
+            if (!conn->parse_chunk_trailer) {
+                if (conn->body_has_data)
+                    return DATA_NEED_MORE;
+                conn->parse_chunk_trailer = 1;
+            }
+            ret = rewrite_connection_read_headers(conn, fd);
+            if (ret == DATA_COMPLETED) {
+                conn->body_is_closed = 1;
+            }
+            return ret;
+        }
+
+        /* if we get here, body_length > 0 */
+        if (conn->chunk_length > MAX_BODY_BUFFER)
+            wanted = MAX_BODY_BUFFER;
+        else
+            wanted = (int)conn->chunk_length;
+        break;
+
+    default:
+        ;
+    }
+
+    /* we don't want more than MAX_BODY_BUFFER bytes in the
+     * buffer we used to pass the body */
+    current = str->n;
+    avail   = MAX_BODY_BUFFER - current;
+    if (avail <= 0) {
+        /* wait for some flush */
+        conn->body_is_full = 1;
+        D("%s: waiting to flush %d bytes", 
+          root->name, current);
+        return DATA_NEED_MORE;
+    }
+
+    if (wanted > avail)
+        wanted = avail;
+
+    ret = proxy_connection_receive(root, fd, wanted);
+    conn->body_has_data = (str->n > 0);
+    conn->body_is_full  = (str->n == MAX_BODY_BUFFER);
+
+    if (ret == DATA_ERROR) {
+        if (conn->body_mode == BODY_UNTIL_CLOSE) {
+            /* a disconnection here is normal and signals the
+             * end of the body */
+            conn->body_total    += root->str_recv;
+            D("%s: body completed by close (%lld bytes)", 
+                root->name, conn->body_total);
+            conn->body_is_closed = 1;
+            ret = DATA_COMPLETED;
+        }
+    } else {
+        avail = root->str_recv;
+        ret   = DATA_NEED_MORE;  /* we're not really done yet */
+
+        switch (conn->body_mode) {
+        case BODY_CHUNKED:
+            conn->chunk_total  += avail;
+            conn->chunk_length -= avail;
+
+            if (conn->chunk_length == 0) {
+                D("%s: chunk completed (%lld bytes)", 
+                    root->name, conn->chunk_length);
+                conn->body_total  += conn->chunk_total;
+                conn->chunk_total  = 0;
+                conn->chunk_length = -1;
+            }
+            break;
+
+        case BODY_KNOWN_LENGTH:
+            conn->body_length -= avail;
+            conn->body_total  += avail;
+
+            if (conn->body_length == 0) {
+                D("%s: body completed (%lld bytes)", 
+                    root->name, conn->body_total);
+                conn->body_is_closed = 1;
+                ret = DATA_COMPLETED;
+            }
+            break;
+
+        case BODY_UNTIL_CLOSE:
+            conn->body_total += avail;
+            break;
+
+        default:
+            ;
+        }
+    }
+    return ret;
+}
+
+static DataStatus
+rewrite_connection_send_body( RewriteConnection*  conn, int  fd )
+{
+    ProxyConnection*  root   = conn->root;
+    stralloc_t*       str    = root->str;
+    DataStatus        ret    = DATA_NEED_MORE;
+
+    if (conn->body_has_data) {
+        ret = proxy_connection_send(root, fd);
+        if (ret != DATA_ERROR) {
+            int  pos = root->str_pos;
+
+            memmove(str->s, str->s+pos, str->n-pos);
+            str->n         -= pos;
+            root->str_pos   = 0;
+            conn->body_is_full  = (str->n == MAX_BODY_BUFFER);
+            conn->body_has_data = (str->n > 0);
+            conn->body_sent    += root->str_sent;
+
+            /* ensure that we return DATA_COMPLETED only when
+            * we have sent everything, and there is no more
+            * body pieces to read */
+            if (ret == DATA_COMPLETED) {
+                if (!conn->body_is_closed || conn->body_has_data)
+                    ret = DATA_NEED_MORE;
+                else {
+                    D("%s: sent all body (%lld bytes)",
+                        root->name, conn->body_sent);
+                }
+            }
+            D("%s: sent closed=%d data=%d n=%d ret=%d",
+                root->name, conn->body_is_closed,
+                conn->body_has_data, str->n,
+                ret);
+        }
+    }
+    return ret;
+}
+
+
+static void
+rewrite_connection_select( ProxyConnection*  root,
+                           ProxySelect*      sel )
+{
+    RewriteConnection*  conn = (RewriteConnection*)root;
+    int  slirp = conn->slirp_fd;
+    int  proxy = root->socket;
+
+    switch (conn->state) {
+        case STATE_CONNECTING:
+        case STATE_CREATE_SOCKET_PAIR:
+            /* try to connect to the proxy server */
+            proxy_select_set( sel, proxy, PROXY_SELECT_WRITE );
+            break;
+
+        case STATE_REQUEST_FIRST_LINE:
+        case STATE_REQUEST_HEADERS:
+            proxy_select_set( sel, slirp, PROXY_SELECT_READ );
+            break;
+
+        case STATE_REQUEST_SEND:
+            proxy_select_set( sel, proxy, PROXY_SELECT_WRITE );
+            break;
+
+        case STATE_REQUEST_BODY:
+            if (!conn->body_is_closed && !conn->body_is_full)
+                proxy_select_set( sel, slirp, PROXY_SELECT_READ );
+
+            if (conn->body_has_data)
+                proxy_select_set( sel, proxy, PROXY_SELECT_WRITE );
+            break;
+
+        case STATE_REPLY_FIRST_LINE:
+        case STATE_REPLY_HEADERS:
+            proxy_select_set( sel, proxy, PROXY_SELECT_READ );
+            break;
+
+        case STATE_REPLY_SEND:
+            proxy_select_set( sel, slirp, PROXY_SELECT_WRITE );
+            break;
+
+        case STATE_REPLY_BODY:
+            if (conn->body_has_data)
+                proxy_select_set( sel, slirp, PROXY_SELECT_WRITE );
+
+            if (!conn->body_is_closed && !conn->body_is_full)
+                proxy_select_set( sel, proxy, PROXY_SELECT_READ );
+            break;
+        default:
+            ;
+    };
+}
+
+static void
+rewrite_connection_poll( ProxyConnection*  root,
+                         ProxySelect*      sel )
+{
+    RewriteConnection*  conn = (RewriteConnection*)root;
+
+    int         slirp     = conn->slirp_fd;
+    int         proxy     = root->socket;
+    int         has_slirp = proxy_select_poll(sel, slirp);
+    int         has_proxy = proxy_select_poll(sel, proxy);
+    DataStatus  ret       = DATA_NEED_MORE;
+
+    switch (conn->state) {
+        case STATE_CONNECTING:
+            if (has_proxy) {
+                PROXY_LOG("%s: connected to proxy", root->name);
+                conn->state = STATE_CREATE_SOCKET_PAIR;
+            }
+            break;
+
+        case STATE_CREATE_SOCKET_PAIR:
+            if (has_proxy) {
+                if (rewrite_connection_create_sockets(conn) < 0) {
+                    ret = DATA_ERROR;
+                } else {
+                    D("%s: socket pair created", root->name);
+                    conn->state = STATE_REQUEST_FIRST_LINE;
+                }
+            }
+            break;
+
+        case STATE_REQUEST_FIRST_LINE:
+            if (has_slirp) {
+                ret = rewrite_connection_read_request(conn);
+                if (ret == DATA_COMPLETED) {
+                    PROXY_LOG("%s: request first line ok", root->name);
+                    conn->state = STATE_REQUEST_HEADERS;
+                }
+            }
+            break;
+
+        case STATE_REQUEST_HEADERS:
+            if (has_slirp) {
+                ret = rewrite_connection_read_headers(conn, slirp);
+                if (ret == DATA_COMPLETED) {
+                    PROXY_LOG("%s: request headers ok", root->name);
+                    if (rewrite_connection_rewrite_request(conn) < 0)
+                        ret = DATA_ERROR;
+                    else
+                        conn->state = STATE_REQUEST_SEND;
+                }
+            }
+            break;
+
+        case STATE_REQUEST_SEND:
+            if (has_proxy) {
+                ret = proxy_connection_send(root, proxy);
+                if (ret == DATA_COMPLETED) {
+                    if (rewrite_connection_get_body_length(conn, 1) < 0) {
+                        ret = DATA_ERROR;
+                    } else if (conn->body_mode != BODY_NONE) {
+                        PROXY_LOG("%s: request sent, waiting for body",
+                                   root->name);
+                        conn->state = STATE_REQUEST_BODY;
+                    } else {
+                        PROXY_LOG("%s: request sent, waiting for reply",
+                                  root->name);
+                        conn->state = STATE_REPLY_FIRST_LINE;
+                    }
+                }
+            }
+            break;
+
+        case STATE_REQUEST_BODY:
+            if (has_slirp) {
+                ret = rewrite_connection_read_body(conn, slirp);
+            }
+            if (ret != DATA_ERROR && has_proxy) {
+                ret = rewrite_connection_send_body(conn, proxy);
+                if (ret == DATA_COMPLETED) {
+                    PROXY_LOG("%s: request body ok, waiting for reply",
+                              root->name);
+                    conn->state = STATE_REPLY_FIRST_LINE;
+                }
+            }
+            break;
+
+        case STATE_REPLY_FIRST_LINE:
+            if (has_proxy) {
+                ret = rewrite_connection_read_reply(conn);
+                if (ret == DATA_COMPLETED) {
+                    PROXY_LOG("%s: reply first line ok", root->name);
+                    conn->state = STATE_REPLY_HEADERS;
+                }
+            }
+            break;
+
+        case STATE_REPLY_HEADERS:
+            if (has_proxy) {
+                ret = rewrite_connection_read_headers(conn, proxy);
+                if (ret == DATA_COMPLETED) {
+                    PROXY_LOG("%s: reply headers ok", root->name);
+                    if (rewrite_connection_rewrite_reply(conn) < 0)
+                        ret = DATA_ERROR;
+                    else
+                        conn->state = STATE_REPLY_SEND;
+                }
+            }
+            break;
+
+        case STATE_REPLY_SEND:
+            if (has_slirp) {
+                ret = proxy_connection_send(conn->root, slirp);
+                if (ret == DATA_COMPLETED) {
+                    if (rewrite_connection_get_body_length(conn, 0) < 0) {
+                        ret = DATA_ERROR;
+                    } else if (conn->body_mode != BODY_NONE) {
+                        PROXY_LOG("%s: reply sent, waiting for body",
+                                  root->name);
+                        conn->state = STATE_REPLY_BODY;
+                    } else {
+                        PROXY_LOG("%s: reply sent, looping to waiting request",
+                                  root->name);
+                        conn->state = STATE_REQUEST_FIRST_LINE;
+                    }
+                }
+            }
+            break;
+
+        case STATE_REPLY_BODY:
+            if (has_proxy) {
+                ret = rewrite_connection_read_body(conn, proxy);
+            }
+            if (ret != DATA_ERROR && has_slirp) {
+                ret = rewrite_connection_send_body(conn, slirp);
+                if (ret == DATA_COMPLETED) {
+                    if (conn->body_mode == BODY_UNTIL_CLOSE) {
+                        PROXY_LOG("%s: closing connection", root->name);
+                        ret = DATA_ERROR;
+                    } else {
+                        PROXY_LOG("%s: reply body ok, looping to waiting request",
+                                root->name);
+                        conn->state = STATE_REQUEST_FIRST_LINE;
+                    }
+                }
+            }
+            break;
+
+        default:
+            ;
+    }
+    if (ret == DATA_ERROR)
+        proxy_connection_free(root, 0, PROXY_EVENT_NONE);
+
+    return;
+}
+
+
+ProxyConnection*
+http_rewriter_connect( HttpService*  service,
+                       SockAddress*  address )
+{
+    RewriteConnection*  conn;
+    int                 s;
+
+    s = socket_create_inet( SOCKET_STREAM );
+    if (s < 0)
+        return NULL;
+
+    conn = qemu_mallocz(sizeof(*conn));
+    if (conn == NULL) {
+        socket_close(s);
+        return NULL;
+    }
+
+    proxy_connection_init( conn->root, s, address, service->root,
+                           rewrite_connection_free,
+                           rewrite_connection_select,
+                           rewrite_connection_poll );
+
+    if ( rewrite_connection_init( conn ) < 0 ) {
+        rewrite_connection_free( conn->root );
+        return NULL;
+    }
+
+    return conn->root;
+}