Support large file uploads

[cascardo/libreceita.git] / rnetclient.c

diff --git a/rnetclient.c b/rnetclient.c
index 2b98cc4..d264c72 100644 (file)
--- a/rnetclient.c
+++ b/rnetclient.c
@@ -31,6 +31,10 @@
 #include "rnet_message.h"
 #include "rnet_encode.h"
 
+static size_t chars2len (unsigned char buf[2]) {
+       return (buf[0] << 8 | buf[1]);
+}
+
 static void * get_creds(char *certfile)
 {
        static gnutls_certificate_credentials_t cred;
@@ -94,7 +98,7 @@ static int inflateRecord(char *buffer, size_t len, char **out, size_t *olen)
        zstrm.opaque = Z_NULL;
        if ((r = inflateInit(&zstrm)) != Z_OK)
                return -1;
-       *olen = (buffer[3] << 8 | buffer[4]);
+       *olen = chars2len(buffer+3);
        *out = malloc(*olen);
        if (!out) {
                inflateEnd(&zstrm);
@@ -176,12 +180,51 @@ static void usage(void)
 
 static int rnet_send(gnutls_session_t session, char *buffer, size_t len, int header)
 {
-       char *out;
-       size_t olen;
-       deflateRecord(buffer, len, &out, &olen, header);
-       gnutls_record_send(session, out, olen);
-       free(out);
-       return 0;
+       int r = 0;
+       /* Large files have to be uploaded as multiple
+          separately-deflated chunks, because the compressed and
+          uncompressed lengths in each record are encoded in unsigned
+          16-bit integers each.
+
+          The header can't be split into multiple chunks, and it
+          should never have to, since it won't ever get even close to
+          64KiB.
+
+          The uploaded file may be larger: to upload such large
+          files, it suffices to send multiple records till the entire
+          file is transferred, without waiting for a response.  Since
+          we've alread informed the server of the file size in the
+          header, it knows exactly how much data to expect before
+          sending a response.  It will only send an error message
+          before that if it times us out.
+
+          Odds are that any reasonably large size will do, but it
+          can't be too close to 64KiB, otherwise there won't be room
+          for the compressed length should it not compress well,
+          which should never happen for capital-ASCII-only
+          declaration files, but who knows?
+
+          This chunk size worked at the first try, uploading a
+          ~100KiB file, so let's stick with it.  */
+       const int maxc = 64472;
+       if (header && len > maxc)
+               return -1;
+
+       do {
+               char *out = NULL;
+               size_t olen;
+               size_t clen = len < maxc ? len : maxc;
+               r = deflateRecord(buffer, clen, &out, &olen, header);
+               if (!r) {
+                       size_t n = gnutls_record_send(session, out, olen);
+                       if (n != olen)
+                               r = -1;
+               }
+               free(out);
+               buffer += clen;
+               len -= clen;
+       } while (len && !r);
+       return r;
 }
 
 static int rnet_recv(gnutls_session_t session, struct rnet_message **message)
@@ -195,7 +238,7 @@ static int rnet_recv(gnutls_session_t session, struct rnet_message **message)
        buffer = (*message)->buffer;
        r = gnutls_record_recv(session, buffer, 6);
        if (buffer[0] == 0x01) {
-               len = (buffer[1] << 8 | buffer[2]);
+               len = chars2len(buffer+1);
                rnet_message_expand(message, len);
                buffer = (*message)->buffer + 6;
                r = gnutls_record_recv(session, buffer, len);
@@ -207,7 +250,7 @@ static int rnet_recv(gnutls_session_t session, struct rnet_message **message)
                (*message)->len = olen;
                free(out);
        } else {
-               len = (buffer[1] << 8 | buffer[2]);
+               len = chars2len(buffer+1);
                rnet_message_expand(message, len - 1);
                buffer = (*message)->buffer + 6;
                r = gnutls_record_recv(session, buffer, len - 1);
@@ -311,7 +354,7 @@ int main(int argc, char **argv)
                        r == EAI_SYSTEM ? strerror(errno) : gai_strerror(r));
                exit(1);
        }
-       gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t) c);
+       gnutls_transport_set_ptr(session, (gnutls_transport_ptr_t)(intptr_t) c);
        r = handshake(c);
        if (r < 0) {
                exit(1);