From f28249c5855506a2e089fc79a429f59cef88b085 Mon Sep 17 00:00:00 2001
From: Vsevolod Stakhov <vsevolod@highsecure.ru>
Date: Mon, 8 May 2017 17:27:18 +0100
Subject: [PATCH] [Feature] Add compression/decompression to proxy

---
 src/rspamd_proxy.c | 105 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)

diff --git a/src/rspamd_proxy.c b/src/rspamd_proxy.c
index acbdafdb7..d485851bf 100644
--- a/src/rspamd_proxy.c
+++ b/src/rspamd_proxy.c
@@ -33,6 +33,7 @@
 #include "ottery.h"
 #include "unix-std.h"
 #include "libserver/milter.h"
+#include "contrib/zstd/zstd.h"
 
 /* Rotate keys each minute by default */
 #define DEFAULT_ROTATION_TIME 60.0
@@ -902,6 +903,110 @@ proxy_session_dtor (struct rspamd_proxy_session *session)
 	g_slice_free1 (sizeof (*session), session);
 }
 
+static void
+proxy_request_compress (struct rspamd_http_message *msg)
+{
+	guint flags;
+	ZSTD_CCtx *zctx;
+	rspamd_fstring_t *body;
+	const gchar *in;
+	gsize inlen;
+
+	flags = rspamd_http_message_get_flags (msg);
+
+	if (!rspamd_http_message_find_header (msg, "compression")) {
+		if ((flags & RSPAMD_HTTP_FLAG_SHMEM) ||
+				!(flags & RSPAMD_HTTP_FLAG_HAS_BODY)) {
+			/* Cannot compress shared or empty message */
+			return;
+		}
+
+		in = rspamd_http_message_get_body (msg, &inlen);
+
+		if (in == NULL || inlen == 0) {
+			return;
+		}
+
+		body = rspamd_fstring_sized_new (ZSTD_compressBound (inlen));
+		zctx = ZSTD_createCCtx ();
+		body->len = ZSTD_compressCCtx (zctx, body->str, body->allocated,
+				in, inlen, 1);
+
+		if (ZSTD_isError (body->len)) {
+			msg_err ("compression error");
+			rspamd_fstring_free (body);
+			ZSTD_freeCCtx (zctx);
+
+			return;
+		}
+
+		ZSTD_freeCCtx (zctx);
+		rspamd_http_message_set_body_from_fstring_steal (msg, body);
+		rspamd_http_message_add_header (msg, "Compression", "zstd");
+	}
+}
+
+static void
+proxy_request_decompress (struct rspamd_http_message *msg)
+{
+	rspamd_fstring_t *body;
+	const gchar *in;
+	gsize inlen, outlen, r;
+	ZSTD_DStream *zstream;
+	ZSTD_inBuffer zin;
+	ZSTD_outBuffer zout;
+
+	if (rspamd_http_message_find_header (msg, "compression")) {
+		in = rspamd_http_message_get_body (msg, &inlen);
+
+		if (in == NULL || inlen == 0) {
+			return;
+		}
+
+		zstream = ZSTD_createDStream ();
+		ZSTD_initDStream (zstream);
+
+		zin.pos = 0;
+		zin.src = in;
+		zin.size = inlen;
+
+		if ((outlen = ZSTD_getDecompressedSize (zin.src, zin.size)) == 0) {
+			outlen = ZSTD_DStreamOutSize ();
+		}
+
+		body = rspamd_fstring_sized_new (outlen);
+		zout.dst = body->str;
+		zout.pos = 0;
+		zout.size = outlen;
+
+		while (zin.pos < zin.size) {
+			r = ZSTD_decompressStream (zstream, &zout, &zin);
+
+			if (ZSTD_isError (r)) {
+				msg_err ("Decompression error: %s", ZSTD_getErrorName (r));
+				ZSTD_freeDStream (zstream);
+				rspamd_fstring_free (body);
+
+				return;
+			}
+
+			if (zout.pos == zout.size) {
+				/* We need to extend output buffer */
+				zout.size = zout.size * 1.5 + 1.0;
+				body = rspamd_fstring_grow (body, zout.size);
+				zout.size = body->allocated;
+				zout.dst = body->str;
+			}
+		}
+
+		ZSTD_freeDStream (zstream);
+		rspamd_http_message_set_body_from_fstring_steal (msg, body);
+		rspamd_http_message_remove_header (msg, "Compression");
+	}
+
+	return;
+}
+
 static struct rspamd_proxy_session *
 proxy_session_refresh (struct rspamd_proxy_session *session)
 {
-- 
2.39.5