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/*
* libwebsockets - small server side websockets and web server implementation
*
* Copyright (C) 2010 - 2019 Andy Green <andy@warmcat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include "private-lib-core.h"
/* compression methods listed in order of preference */
struct lws_compression_support *lcs_available[] = {
#if defined(LWS_WITH_HTTP_BROTLI)
&lcs_brotli,
#endif
&lcs_deflate,
};
/* compute acceptable compression encodings while we still have an ah */
int
lws_http_compression_validate(struct lws *wsi)
{
const char *a;
size_t n;
wsi->http.comp_accept_mask = 0;
if (!wsi->http.ah || !lwsi_role_server(wsi))
return 0;
a = lws_hdr_simple_ptr(wsi, WSI_TOKEN_HTTP_ACCEPT_ENCODING);
if (!a)
return 0;
for (n = 0; n < LWS_ARRAY_SIZE(lcs_available); n++)
if (strstr(a, lcs_available[n]->encoding_name))
wsi->http.comp_accept_mask |= 1 << n;
return 0;
}
int
lws_http_compression_apply(struct lws *wsi, const char *name,
unsigned char **p, unsigned char *end, char decomp)
{
size_t n;
for (n = 0; n < LWS_ARRAY_SIZE(lcs_available); n++) {
/* if name is non-NULL, choose only that compression method */
if (name && !strcmp(lcs_available[n]->encoding_name, name))
continue;
/*
* If we're the server, confirm that the client told us he could
* handle this kind of compression transform...
*/
if (!decomp && !(wsi->http.comp_accept_mask & (1 << n)))
continue;
/* let's go with this one then... */
break;
}
if (n == LWS_ARRAY_SIZE(lcs_available))
return 1;
lcs_available[n]->init_compression(&wsi->http.comp_ctx, decomp);
if (!wsi->http.comp_ctx.u.generic_ctx_ptr) {
lwsl_err("%s: init_compression %d failed\n", __func__, (int)n);
return 1;
}
wsi->http.lcs = lcs_available[n];
wsi->http.comp_ctx.may_have_more = 0;
wsi->http.comp_ctx.final_on_input_side = 0;
wsi->http.comp_ctx.chunking = 0;
wsi->http.comp_ctx.is_decompression = decomp;
if (lws_add_http_header_by_token(wsi, WSI_TOKEN_HTTP_CONTENT_ENCODING,
(unsigned char *)lcs_available[n]->encoding_name,
strlen(lcs_available[n]->encoding_name), p, end))
return -1;
lwsl_info("%s: wsi %p: applied %s content-encoding\n", __func__,
wsi, lcs_available[n]->encoding_name);
return 0;
}
void
lws_http_compression_destroy(struct lws *wsi)
{
if (!wsi->http.lcs || !wsi->http.comp_ctx.u.generic_ctx_ptr)
return;
wsi->http.lcs->destroy(&wsi->http.comp_ctx);
wsi->http.lcs = NULL;
}
/*
* This manages the compression transform independent of h1 or h2.
*
* wsi->buflist_comp stashes pre-transform input that was not yet compressed
*/
int
lws_http_compression_transform(struct lws *wsi, unsigned char *buf,
size_t len, enum lws_write_protocol *wp,
unsigned char **outbuf, size_t *olen_oused)
{
size_t ilen_iused = len;
int n, use = 0, wp1f = (*wp) & 0x1f;
lws_comp_ctx_t *ctx = &wsi->http.comp_ctx;
ctx->may_have_more = 0;
if (!wsi->http.lcs ||
(wp1f != LWS_WRITE_HTTP && wp1f != LWS_WRITE_HTTP_FINAL)) {
*outbuf = buf;
*olen_oused = len;
return 0;
}
if (wp1f == LWS_WRITE_HTTP_FINAL) {
/*
* ...we may get a large buffer that represents the final input
* buffer, but it may form multiple frames after being
* tranformed by compression; only the last of those is actually
* the final frame on the output stream.
*
* Note that we have received the FINAL input, and downgrade it
* to a non-final for now.
*/
ctx->final_on_input_side = 1;
*wp = LWS_WRITE_HTTP | ((*wp) & ~0x1f);
}
if (ctx->buflist_comp) {
/*
* we can't send this new stuff when we have old stuff
* buffered and not compressed yet. Add it to the tail
* and switch to trying to process the head.
*/
if (buf && len) {
if (lws_buflist_append_segment(
&ctx->buflist_comp, buf, len) < 0)
return -1;
lwsl_debug("%s: %p: adding %d to comp buflist\n",
__func__,wsi, (int)len);
}
len = lws_buflist_next_segment_len(&ctx->buflist_comp, &buf);
ilen_iused = len;
use = 1;
lwsl_debug("%s: %p: trying comp buflist %d\n", __func__, wsi,
(int)len);
}
if (!buf && ilen_iused)
return 0;
lwsl_debug("%s: %p: pre-process: ilen_iused %d, olen_oused %d\n",
__func__, wsi, (int)ilen_iused, (int)*olen_oused);
n = wsi->http.lcs->process(ctx, buf, &ilen_iused, *outbuf, olen_oused);
if (n && n != 1) {
lwsl_err("%s: problem with compression\n", __func__);
return -1;
}
if (!ctx->may_have_more && ctx->final_on_input_side)
*wp = LWS_WRITE_HTTP_FINAL | ((*wp) & ~0x1f);
lwsl_debug("%s: %p: more %d, ilen_iused %d\n", __func__, wsi,
ctx->may_have_more, (int)ilen_iused);
if (use && ilen_iused) {
/*
* we were flushing stuff from the buflist head... account for
* however much actually got processed by the compression
* transform
*/
lws_buflist_use_segment(&ctx->buflist_comp, ilen_iused);
lwsl_debug("%s: %p: marking %d of comp buflist as used "
"(ctx->buflist_comp %p)\n", __func__, wsi,
(int)len, ctx->buflist_comp);
}
if (!use && ilen_iused != len) {
/*
* ...we were sending stuff from the caller directly and not
* all of it got processed... stash on the buflist tail
*/
if (lws_buflist_append_segment(&ctx->buflist_comp,
buf + ilen_iused, len - ilen_iused) < 0)
return -1;
lwsl_debug("%s: buffering %d unused comp input\n", __func__,
(int)(len - ilen_iused));
}
if (ctx->buflist_comp || ctx->may_have_more)
lws_callback_on_writable(wsi);
return 0;
}