Adding upstream version 2.9.5.upstream/2.9.5

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1076 insertions, 0 deletions

diff --git a/src/flt_http_comp.c b/src/flt_http_comp.c
new file mode 100644
index 0000000..30f9d2a
--- /dev/null
+++ b/src/flt_http_comp.c
@@ -0,0 +1,1076 @@
+/*
+ * Stream filters related variables and functions.
+ *
+ * Copyright (C) 2015 Qualys Inc., Christopher Faulet <cfaulet@qualys.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <haproxy/api.h>
+#include <haproxy/cfgparse.h>
+#include <haproxy/compression.h>
+#include <haproxy/dynbuf.h>
+#include <haproxy/filters.h>
+#include <haproxy/http.h>
+#include <haproxy/http_ana-t.h>
+#include <haproxy/http_htx.h>
+#include <haproxy/htx.h>
+#include <haproxy/list.h>
+#include <haproxy/proxy.h>
+#include <haproxy/sample.h>
+#include <haproxy/stream.h>
+#include <haproxy/tools.h>
+
+#define COMP_STATE_PROCESSING 0x01
+
+const char *http_comp_flt_id = "compression filter";
+
+struct flt_ops comp_ops;
+
+struct comp_state {
+	/*
+	 * For both comp_ctx and comp_algo, COMP_DIR_REQ is the index
+	 * for requests, and COMP_DIR_RES for responses
+	 */
+	struct comp_ctx  *comp_ctx[2];   /* compression context */
+	struct comp_algo *comp_algo[2];  /* compression algorithm if not NULL */
+	unsigned int      flags;      /* COMP_STATE_* */
+};
+
+/* Pools used to allocate comp_state structs */
+DECLARE_STATIC_POOL(pool_head_comp_state, "comp_state", sizeof(struct comp_state));
+
+static THREAD_LOCAL struct buffer tmpbuf;
+static THREAD_LOCAL struct buffer zbuf;
+
+static int select_compression_request_header(struct comp_state *st,
+					     struct stream *s,
+					     struct http_msg *msg);
+static int select_compression_response_header(struct comp_state *st,
+					      struct stream *s,
+					      struct http_msg *msg);
+static int set_compression_header(struct comp_state *st,
+			          struct stream *s,
+				  struct http_msg *msg);
+
+static int htx_compression_buffer_init(struct htx *htx, struct buffer *out);
+static int htx_compression_buffer_add_data(struct comp_state *st, const char *data, size_t len,
+					    struct buffer *out, int dir);
+static int htx_compression_buffer_end(struct comp_state *st, struct buffer *out, int end, int dir);
+
+/***********************************************************************/
+static int
+comp_flt_init(struct proxy *px, struct flt_conf *fconf)
+{
+	fconf->flags |= FLT_CFG_FL_HTX;
+	return 0;
+}
+
+static int
+comp_flt_init_per_thread(struct proxy *px, struct flt_conf *fconf)
+{
+	if (b_alloc(&tmpbuf) == NULL)
+		return -1;
+	if (b_alloc(&zbuf) == NULL)
+		return -1;
+	return 0;
+}
+
+static void
+comp_flt_deinit_per_thread(struct proxy *px, struct flt_conf *fconf)
+{
+	if (tmpbuf.size)
+		b_free(&tmpbuf);
+	if (zbuf.size)
+		b_free(&zbuf);
+}
+
+static int
+comp_strm_init(struct stream *s, struct filter *filter)
+{
+	struct comp_state *st;
+
+	st = pool_alloc(pool_head_comp_state);
+	if (st == NULL)
+		return -1;
+
+	st->comp_algo[COMP_DIR_REQ] = NULL;
+	st->comp_algo[COMP_DIR_RES] = NULL;
+	st->comp_ctx[COMP_DIR_REQ]  = NULL;
+	st->comp_ctx[COMP_DIR_RES] = NULL;
+	st->flags     = 0;
+	filter->ctx   = st;
+
+	/* Register post-analyzer on AN_RES_WAIT_HTTP because we need to
+	 * analyze response headers before http-response rules execution
+	 * to be sure we can use res.comp and res.comp_algo sample
+	 * fetches */
+	filter->post_analyzers |= AN_RES_WAIT_HTTP;
+	return 1;
+}
+
+static void
+comp_strm_deinit(struct stream *s, struct filter *filter)
+{
+	struct comp_state *st = filter->ctx;
+
+	if (!st)
+		return;
+
+	/* release any possible compression context */
+	if (st->comp_algo[COMP_DIR_REQ])
+		st->comp_algo[COMP_DIR_REQ]->end(&st->comp_ctx[COMP_DIR_REQ]);
+	if (st->comp_algo[COMP_DIR_RES])
+		st->comp_algo[COMP_DIR_RES]->end(&st->comp_ctx[COMP_DIR_RES]);
+	pool_free(pool_head_comp_state, st);
+	filter->ctx = NULL;
+}
+
+static void
+comp_prepare_compress_request(struct comp_state *st, struct stream *s, struct http_msg *msg)
+{
+	struct htx *htx = htxbuf(&msg->chn->buf);
+	struct http_txn *txn = s->txn;
+	struct http_hdr_ctx ctx;
+	struct comp_type *comp_type;
+
+	ctx.blk = NULL;
+	/* Already compressed, don't bother */
+	if (http_find_header(htx, ist("Content-Encoding"), &ctx, 1))
+		return;
+	/* HTTP < 1.1 should not be compressed */
+	if (!(msg->flags & HTTP_MSGF_VER_11) || !(txn->req.flags & HTTP_MSGF_VER_11))
+		return;
+	comp_type = NULL;
+
+	/*
+	 * We don't want to compress content-types not listed in the "compression type" directive if any. If no content-type was found but configuration
+	 * requires one, we don't compress either. Backend has the priority.
+	 */
+	ctx.blk = NULL;
+	if (http_find_header(htx, ist("Content-Type"), &ctx, 1)) {
+		if ((s->be->comp && (comp_type = s->be->comp->types_req)) ||
+		    (strm_fe(s)->comp && (comp_type = strm_fe(s)->comp->types_req))) {
+			for (; comp_type; comp_type = comp_type->next) {
+				if (ctx.value.len >= comp_type->name_len &&
+				    strncasecmp(ctx.value.ptr, comp_type->name, comp_type->name_len) == 0)
+					/* this Content-Type should be compressed */
+					break;
+			}
+			/* this Content-Type should not be compressed */
+			if (comp_type == NULL)
+				goto fail;
+		}
+	}
+	else { /* no content-type header */
+		if ((s->be->comp && s->be->comp->types_req) ||
+		    (strm_fe(s)->comp && strm_fe(s)->comp->types_req))
+			goto fail; /* a content-type was required */
+	}
+
+	/* limit compression rate */
+	if (global.comp_rate_lim > 0)
+		if (read_freq_ctr(&global.comp_bps_in) > global.comp_rate_lim)
+			goto fail;
+
+	/* limit cpu usage */
+	if (th_ctx->idle_pct < compress_min_idle)
+		goto fail;
+
+	if (txn->meth == HTTP_METH_HEAD)
+		return;
+	if (s->be->comp && s->be->comp->algo_req != NULL)
+		st->comp_algo[COMP_DIR_REQ] = s->be->comp->algo_req;
+	else if (strm_fe(s)->comp && strm_fe(s)->comp->algo_req != NULL)
+		st->comp_algo[COMP_DIR_REQ] = strm_fe(s)->comp->algo_req;
+	else
+		goto fail; /* no algo selected: nothing to do */
+
+
+	/* limit compression rate */
+	if (global.comp_rate_lim > 0)
+		if (read_freq_ctr(&global.comp_bps_in) > global.comp_rate_lim)
+			goto fail;
+
+	/* limit cpu usage */
+	if (th_ctx->idle_pct < compress_min_idle)
+		goto fail;
+
+	/* initialize compression */
+	if (st->comp_algo[COMP_DIR_REQ]->init(&st->comp_ctx[COMP_DIR_REQ], global.tune.comp_maxlevel) < 0)
+		goto fail;
+
+	return;
+fail:
+	st->comp_algo[COMP_DIR_REQ] = NULL;
+}
+
+static int
+comp_http_headers(struct stream *s, struct filter *filter, struct http_msg *msg)
+{
+	struct comp_state *st = filter->ctx;
+	int comp_flags = 0;
+
+	if (!strm_fe(s)->comp && !s->be->comp)
+		goto end;
+	if (strm_fe(s)->comp)
+		comp_flags |= strm_fe(s)->comp->flags;
+	if (s->be->comp)
+		comp_flags |= s->be->comp->flags;
+
+	if (!(msg->chn->flags & CF_ISRESP)) {
+		if (comp_flags & COMP_FL_DIR_REQ) {
+			    comp_prepare_compress_request(st, s, msg);
+			    if (st->comp_algo[COMP_DIR_REQ]) {
+				    if (!set_compression_header(st, s, msg))
+					    goto end;
+				    register_data_filter(s, msg->chn, filter);
+				    st->flags |= COMP_STATE_PROCESSING;
+			    }
+		}
+		if (comp_flags & COMP_FL_DIR_RES)
+			select_compression_request_header(st, s, msg);
+	} else if (comp_flags & COMP_FL_DIR_RES) {
+		/* Response headers have already been checked in
+		 * comp_http_post_analyze callback. */
+		if (st->comp_algo[COMP_DIR_RES]) {
+			if (!set_compression_header(st, s, msg))
+				goto end;
+			register_data_filter(s, msg->chn, filter);
+			st->flags |= COMP_STATE_PROCESSING;
+		}
+	}
+
+  end:
+	return 1;
+}
+
+static int
+comp_http_post_analyze(struct stream *s, struct filter *filter,
+		       struct channel *chn, unsigned an_bit)
+{
+	struct http_txn   *txn = s->txn;
+	struct http_msg   *msg = &txn->rsp;
+	struct comp_state *st  = filter->ctx;
+
+	if (an_bit != AN_RES_WAIT_HTTP)
+		goto end;
+
+	if (!strm_fe(s)->comp && !s->be->comp)
+		goto end;
+
+	select_compression_response_header(st, s, msg);
+
+  end:
+	return 1;
+}
+
+static int
+comp_http_payload(struct stream *s, struct filter *filter, struct http_msg *msg,
+		  unsigned int offset, unsigned int len)
+{
+	struct comp_state *st = filter->ctx;
+	struct htx *htx = htxbuf(&msg->chn->buf);
+	struct htx_ret htxret = htx_find_offset(htx, offset);
+	struct htx_blk *blk, *next;
+	int ret, consumed = 0, to_forward = 0, last = 0;
+	int dir;
+
+	if (msg->chn->flags & CF_ISRESP)
+		dir = COMP_DIR_RES;
+	else
+		dir = COMP_DIR_REQ;
+
+	blk = htxret.blk;
+	offset = htxret.ret;
+	for (next = NULL; blk && len; blk = next) {
+		enum htx_blk_type type = htx_get_blk_type(blk);
+		uint32_t sz = htx_get_blksz(blk);
+		struct ist v;
+
+		next = htx_get_next_blk(htx, blk);
+		while (next && htx_get_blk_type(next) == HTX_BLK_UNUSED)
+			next = htx_get_next_blk(htx, next);
+
+		if (!(st->flags & COMP_STATE_PROCESSING))
+			goto consume;
+
+		if (htx_compression_buffer_init(htx, &trash) < 0) {
+			msg->chn->flags |= CF_WAKE_WRITE;
+			goto end;
+		}
+
+		switch (type) {
+			case HTX_BLK_DATA:
+				/* it is the last data block */
+				last = ((!next && (htx->flags & HTX_FL_EOM)) || (next && htx_get_blk_type(next) != HTX_BLK_DATA));
+				v = htx_get_blk_value(htx, blk);
+				v = istadv(v, offset);
+				if (v.len > len) {
+					last = 0;
+					v.len = len;
+				}
+
+				ret = htx_compression_buffer_add_data(st, v.ptr, v.len, &trash, dir);
+				if (ret < 0 || htx_compression_buffer_end(st, &trash, last, dir) < 0)
+					goto error;
+				BUG_ON(v.len != ret);
+
+				if (ret == sz && !b_data(&trash))
+					next = htx_remove_blk(htx, blk);
+				else {
+					blk = htx_replace_blk_value(htx, blk, v, ist2(b_head(&trash), b_data(&trash)));
+					next = htx_get_next_blk(htx, blk);
+				}
+
+				len -= ret;
+				consumed += ret;
+				to_forward += b_data(&trash);
+				if (last)
+					st->flags &= ~COMP_STATE_PROCESSING;
+				break;
+
+			case HTX_BLK_TLR:
+			case HTX_BLK_EOT:
+				if (htx_compression_buffer_end(st, &trash, 1, dir) < 0)
+					goto error;
+				if (b_data(&trash)) {
+					struct htx_blk *last = htx_add_last_data(htx, ist2(b_head(&trash), b_data(&trash)));
+					if (!last)
+						goto error;
+					blk = htx_get_next_blk(htx, last);
+					if (!blk)
+						goto error;
+					next = htx_get_next_blk(htx, blk);
+					to_forward += b_data(&trash);
+				}
+				st->flags &= ~COMP_STATE_PROCESSING;
+				__fallthrough;
+
+			default:
+			  consume:
+				sz -= offset;
+				if (sz > len)
+					sz = len;
+				consumed += sz;
+				to_forward += sz;
+				len -= sz;
+				break;
+		}
+
+		offset = 0;
+	}
+
+  end:
+	if (to_forward != consumed)
+		flt_update_offsets(filter, msg->chn, to_forward - consumed);
+
+	if (st->comp_ctx[dir] && st->comp_ctx[dir]->cur_lvl > 0) {
+		update_freq_ctr(&global.comp_bps_in, consumed);
+		_HA_ATOMIC_ADD(&strm_fe(s)->fe_counters.comp_in[dir], consumed);
+		_HA_ATOMIC_ADD(&s->be->be_counters.comp_in[dir], consumed);
+		update_freq_ctr(&global.comp_bps_out, to_forward);
+		_HA_ATOMIC_ADD(&strm_fe(s)->fe_counters.comp_out[dir], to_forward);
+		_HA_ATOMIC_ADD(&s->be->be_counters.comp_out[dir], to_forward);
+	} else {
+		_HA_ATOMIC_ADD(&strm_fe(s)->fe_counters.comp_byp[dir], consumed);
+		_HA_ATOMIC_ADD(&s->be->be_counters.comp_byp[dir], consumed);
+	}
+	return to_forward;
+
+  error:
+	return -1;
+}
+
+
+static int
+comp_http_end(struct stream *s, struct filter *filter,
+	      struct http_msg *msg)
+{
+	struct comp_state *st = filter->ctx;
+
+	if (!(msg->chn->flags & CF_ISRESP) || !st || !st->comp_algo[COMP_DIR_RES])
+		goto end;
+
+	if (strm_fe(s)->mode == PR_MODE_HTTP)
+		_HA_ATOMIC_INC(&strm_fe(s)->fe_counters.p.http.comp_rsp);
+	if ((s->flags & SF_BE_ASSIGNED) && (s->be->mode == PR_MODE_HTTP))
+		_HA_ATOMIC_INC(&s->be->be_counters.p.http.comp_rsp);
+ end:
+	return 1;
+}
+
+/***********************************************************************/
+static int
+set_compression_header(struct comp_state *st, struct stream *s, struct http_msg *msg)
+{
+	struct htx *htx = htxbuf(&msg->chn->buf);
+	struct htx_sl *sl;
+	struct http_hdr_ctx ctx, last_vary;
+	struct comp_algo *comp_algo;
+	int comp_index;
+
+	if (msg->chn->flags & CF_ISRESP)
+		comp_index = COMP_DIR_RES;
+	else
+		comp_index = COMP_DIR_REQ;
+
+	sl = http_get_stline(htx);
+	if (!sl)
+		goto error;
+
+	comp_algo = st->comp_algo[comp_index];
+
+	/* add "Transfer-Encoding: chunked" header */
+	if (!(msg->flags & HTTP_MSGF_TE_CHNK)) {
+		if (!http_add_header(htx, ist("Transfer-Encoding"), ist("chunked")))
+			goto error;
+		msg->flags |= HTTP_MSGF_TE_CHNK;
+		sl->flags |= (HTX_SL_F_XFER_ENC|HTX_SL_F_CHNK);
+	}
+
+	/* remove Content-Length header */
+	if (msg->flags & HTTP_MSGF_CNT_LEN) {
+		ctx.blk = NULL;
+		while (http_find_header(htx, ist("Content-Length"), &ctx, 1))
+			http_remove_header(htx, &ctx);
+		msg->flags &= ~HTTP_MSGF_CNT_LEN;
+		sl->flags &= ~HTX_SL_F_CLEN;
+	}
+
+	/* convert "ETag" header to a weak ETag */
+	ctx.blk = NULL;
+	if (http_find_header(htx, ist("ETag"), &ctx, 1)) {
+		if (ctx.value.ptr[0] == '"') {
+			/* This a strong ETag. Convert it to a weak one. */
+			struct ist v = ist2(trash.area, 0);
+			if (istcat(&v, ist("W/"), trash.size) == -1 || istcat(&v, ctx.value, trash.size) == -1)
+				goto error;
+
+			if (!http_replace_header_value(htx, &ctx, v))
+				goto error;
+		}
+	}
+
+	/* Add "Vary: Accept-Encoding" header but only if it is not found. */
+	ctx.blk = NULL;
+	last_vary.blk = NULL;
+	while (http_find_header(htx, ist("Vary"), &ctx, 0)) {
+		if (isteqi(ctx.value, ist("Accept-Encoding")))
+			break;
+		last_vary = ctx;
+	}
+	/* No "Accept-Encoding" value found. */
+	if (ctx.blk == NULL) {
+		if (last_vary.blk == NULL) {
+			/* No Vary header found at all. Add our header */
+			if (!http_add_header(htx, ist("Vary"), ist("Accept-Encoding")))
+				goto error;
+		}
+		else  {
+			/* At least one Vary header found. Append the value to
+			 * the last one.
+			 */
+			if (!http_append_header_value(htx, &last_vary, ist("Accept-Encoding")))
+				goto error;
+		}
+	}
+
+	/*
+	 * Add Content-Encoding header when it's not identity encoding.
+	 * RFC 2616 : Identity encoding: This content-coding is used only in the
+	 * Accept-Encoding header, and SHOULD NOT be used in the Content-Encoding
+	 * header.
+	 */
+	if (comp_algo->cfg_name_len != 8 || memcmp(comp_algo->cfg_name, "identity", 8) != 0) {
+		struct ist v = ist2(comp_algo->ua_name, comp_algo->ua_name_len);
+
+		if (!http_add_header(htx, ist("Content-Encoding"), v))
+			goto error;
+	}
+
+	return 1;
+
+  error:
+	st->comp_algo[comp_index]->end(&st->comp_ctx[comp_index]);
+	st->comp_algo[comp_index] = NULL;
+	return 0;
+}
+
+/*
+ * Selects a compression algorithm depending on the client request.
+ */
+static int
+select_compression_request_header(struct comp_state *st, struct stream *s, struct http_msg *msg)
+{
+	struct htx *htx = htxbuf(&msg->chn->buf);
+	struct http_hdr_ctx ctx;
+	struct comp_algo *comp_algo = NULL;
+	struct comp_algo *comp_algo_back = NULL;
+
+	/* Disable compression for older user agents announcing themselves as "Mozilla/4"
+	 * unless they are known good (MSIE 6 with XP SP2, or MSIE 7 and later).
+	 * See http://zoompf.com/2012/02/lose-the-wait-http-compression for more details.
+	 */
+	ctx.blk = NULL;
+	if (http_find_header(htx, ist("User-Agent"), &ctx, 1) &&
+	    ctx.value.len >= 9 &&
+	    memcmp(ctx.value.ptr, "Mozilla/4", 9) == 0 &&
+	    (ctx.value.len < 31 ||
+	     memcmp(ctx.value.ptr + 25, "MSIE ", 5) != 0 ||
+	     *(ctx.value.ptr + 30) < '6' ||
+	     (*(ctx.value.ptr + 30) == '6' &&
+	      (ctx.value.len < 54 || memcmp(ctx.value.ptr + 51, "SV1", 3) != 0)))) {
+		st->comp_algo[COMP_DIR_RES] = NULL;
+		return 0;
+	}
+
+	/* search for the algo in the backend in priority or the frontend */
+	if ((s->be->comp && (comp_algo_back = s->be->comp->algos_res)) ||
+	    (strm_fe(s)->comp && (comp_algo_back = strm_fe(s)->comp->algos_res))) {
+		int best_q = 0;
+
+		ctx.blk = NULL;
+		while (http_find_header(htx, ist("Accept-Encoding"), &ctx, 0)) {
+			const char *qval;
+			int q;
+			int toklen;
+
+			/* try to isolate the token from the optional q-value */
+			toklen = 0;
+			while (toklen < ctx.value.len && HTTP_IS_TOKEN(*(ctx.value.ptr + toklen)))
+				toklen++;
+
+			qval = ctx.value.ptr + toklen;
+			while (1) {
+				while (qval < istend(ctx.value) && HTTP_IS_LWS(*qval))
+					qval++;
+
+				if (qval >= istend(ctx.value) || *qval != ';') {
+					qval = NULL;
+					break;
+				}
+				qval++;
+
+				while (qval < istend(ctx.value) && HTTP_IS_LWS(*qval))
+					qval++;
+
+				if (qval >= istend(ctx.value)) {
+					qval = NULL;
+					break;
+				}
+				if (strncmp(qval, "q=", MIN(istend(ctx.value) - qval, 2)) == 0)
+					break;
+
+				while (qval < istend(ctx.value) && *qval != ';')
+					qval++;
+			}
+
+			/* here we have qval pointing to the first "q=" attribute or NULL if not found */
+			q = qval ? http_parse_qvalue(qval + 2, NULL) : 1000;
+
+			if (q <= best_q)
+				continue;
+
+			for (comp_algo = comp_algo_back; comp_algo; comp_algo = comp_algo->next) {
+				if (*(ctx.value.ptr) == '*' ||
+				    word_match(ctx.value.ptr, toklen, comp_algo->ua_name, comp_algo->ua_name_len)) {
+					st->comp_algo[COMP_DIR_RES] = comp_algo;
+					best_q = q;
+					break;
+				}
+			}
+		}
+	}
+
+	/* remove all occurrences of the header when "compression offload" is set */
+	if (st->comp_algo[COMP_DIR_RES]) {
+		if ((s->be->comp && (s->be->comp->flags & COMP_FL_OFFLOAD)) ||
+		    (strm_fe(s)->comp && (strm_fe(s)->comp->flags & COMP_FL_OFFLOAD))) {
+			http_remove_header(htx, &ctx);
+			ctx.blk = NULL;
+			while (http_find_header(htx, ist("Accept-Encoding"), &ctx, 1))
+				http_remove_header(htx, &ctx);
+		}
+		return 1;
+	}
+
+	/* identity is implicit does not require headers */
+	if ((s->be->comp && (comp_algo_back = s->be->comp->algos_res)) ||
+	    (strm_fe(s)->comp && (comp_algo_back = strm_fe(s)->comp->algos_res))) {
+		for (comp_algo = comp_algo_back; comp_algo; comp_algo = comp_algo->next) {
+			if (comp_algo->cfg_name_len == 8 && memcmp(comp_algo->cfg_name, "identity", 8) == 0) {
+				st->comp_algo[COMP_DIR_RES] = comp_algo;
+				return 1;
+			}
+		}
+	}
+
+	st->comp_algo[COMP_DIR_RES] = NULL;
+	return 0;
+}
+
+/*
+ * Selects a compression algorithm depending of the server response.
+ */
+static int
+select_compression_response_header(struct comp_state *st, struct stream *s, struct http_msg *msg)
+{
+	struct htx *htx = htxbuf(&msg->chn->buf);
+	struct http_txn *txn = s->txn;
+	struct http_hdr_ctx ctx;
+	struct comp_type *comp_type;
+
+	/* no common compression algorithm was found in request header */
+	if (st->comp_algo[COMP_DIR_RES] == NULL)
+		goto fail;
+
+	/* compression already in progress */
+	if (msg->flags & HTTP_MSGF_COMPRESSING)
+		goto fail;
+
+	/* HTTP < 1.1 should not be compressed */
+	if (!(msg->flags & HTTP_MSGF_VER_11) || !(txn->req.flags & HTTP_MSGF_VER_11))
+		goto fail;
+
+	if (txn->meth == HTTP_METH_HEAD)
+		goto fail;
+
+	/* compress 200,201,202,203 responses only */
+	if ((txn->status != 200) &&
+	    (txn->status != 201) &&
+	    (txn->status != 202) &&
+	    (txn->status != 203))
+		goto fail;
+
+	if (!(msg->flags & HTTP_MSGF_XFER_LEN) || msg->flags & HTTP_MSGF_BODYLESS)
+		goto fail;
+
+	/* content is already compressed */
+	ctx.blk = NULL;
+	if (http_find_header(htx, ist("Content-Encoding"), &ctx, 1))
+		goto fail;
+
+	/* no compression when Cache-Control: no-transform is present in the message */
+	ctx.blk = NULL;
+	while (http_find_header(htx, ist("Cache-Control"), &ctx, 0)) {
+		if (word_match(ctx.value.ptr, ctx.value.len, "no-transform", 12))
+			goto fail;
+	}
+
+	/* no compression when ETag is malformed */
+	ctx.blk = NULL;
+	if (http_find_header(htx, ist("ETag"), &ctx, 1)) {
+		if (http_get_etag_type(ctx.value) == ETAG_INVALID)
+			goto fail;
+	}
+	/* no compression when multiple ETags are present
+	 * Note: Do not reset ctx.blk!
+	 */
+	if (http_find_header(htx, ist("ETag"), &ctx, 1))
+		goto fail;
+
+	comp_type = NULL;
+
+	/* we don't want to compress multipart content-types, nor content-types that are
+	 * not listed in the "compression type" directive if any. If no content-type was
+	 * found but configuration requires one, we don't compress either. Backend has
+	 * the priority.
+	 */
+	ctx.blk = NULL;
+	if (http_find_header(htx, ist("Content-Type"), &ctx, 1)) {
+		if (ctx.value.len >= 9 && strncasecmp("multipart", ctx.value.ptr, 9) == 0)
+			goto fail;
+
+		if ((s->be->comp && (comp_type = s->be->comp->types_res)) ||
+		    (strm_fe(s)->comp && (comp_type = strm_fe(s)->comp->types_res))) {
+			for (; comp_type; comp_type = comp_type->next) {
+				if (ctx.value.len >= comp_type->name_len &&
+				    strncasecmp(ctx.value.ptr, comp_type->name, comp_type->name_len) == 0)
+					/* this Content-Type should be compressed */
+					break;
+			}
+			/* this Content-Type should not be compressed */
+			if (comp_type == NULL)
+				goto fail;
+		}
+	}
+	else { /* no content-type header */
+		if ((s->be->comp && s->be->comp->types_res) ||
+		    (strm_fe(s)->comp && strm_fe(s)->comp->types_res))
+			goto fail; /* a content-type was required */
+	}
+
+	/* limit compression rate */
+	if (global.comp_rate_lim > 0)
+		if (read_freq_ctr(&global.comp_bps_in) > global.comp_rate_lim)
+			goto fail;
+
+	/* limit cpu usage */
+	if (th_ctx->idle_pct < compress_min_idle)
+		goto fail;
+
+	/* initialize compression */
+	if (st->comp_algo[COMP_DIR_RES]->init(&st->comp_ctx[COMP_DIR_RES], global.tune.comp_maxlevel) < 0)
+		goto fail;
+	msg->flags |= HTTP_MSGF_COMPRESSING;
+	return 1;
+
+  fail:
+	st->comp_algo[COMP_DIR_RES] = NULL;
+	return 0;
+}
+
+/***********************************************************************/
+static int
+htx_compression_buffer_init(struct htx *htx, struct buffer *out)
+{
+	/* output stream requires at least 10 bytes for the gzip header, plus
+	 * at least 8 bytes for the gzip trailer (crc+len), plus a possible
+	 * plus at most 5 bytes per 32kB block and 2 bytes to close the stream.
+	 */
+	if (htx_free_space(htx) < 20 + 5 * ((htx->data + 32767) >> 15))
+		return -1;
+	b_reset(out);
+	return 0;
+}
+
+static int
+htx_compression_buffer_add_data(struct comp_state *st, const char *data, size_t len,
+				struct buffer *out, int dir)
+{
+
+	return st->comp_algo[dir]->add_data(st->comp_ctx[dir], data, len, out);
+}
+
+static int
+htx_compression_buffer_end(struct comp_state *st, struct buffer *out, int end, int dir)
+{
+
+	if (end)
+		return st->comp_algo[dir]->finish(st->comp_ctx[dir], out);
+	else
+		return st->comp_algo[dir]->flush(st->comp_ctx[dir], out);
+}
+
+
+/***********************************************************************/
+struct flt_ops comp_ops = {
+	.init              = comp_flt_init,
+	.init_per_thread   = comp_flt_init_per_thread,
+	.deinit_per_thread = comp_flt_deinit_per_thread,
+
+	.attach = comp_strm_init,
+	.detach = comp_strm_deinit,
+
+	.channel_post_analyze  = comp_http_post_analyze,
+
+	.http_headers          = comp_http_headers,
+	.http_payload          = comp_http_payload,
+	.http_end              = comp_http_end,
+};
+
+static int
+parse_compression_options(char **args, int section, struct proxy *proxy,
+			  const struct proxy *defpx, const char *file, int line,
+			  char **err)
+{
+	struct comp    *comp;
+	int ret = 0;
+
+	if (proxy->comp == NULL) {
+		comp = calloc(1, sizeof(*comp));
+		/* Always default to compress responses */
+		comp->flags = COMP_FL_DIR_RES;
+		proxy->comp = comp;
+	}
+	else
+		comp = proxy->comp;
+
+	if (strcmp(args[1], "algo") == 0 || strcmp(args[1], "algo-res") == 0) {
+		struct comp_ctx *ctx;
+		int              cur_arg = 2;
+
+		if (!*args[cur_arg]) {
+			memprintf(err, "parsing [%s:%d] : '%s' expects <algorithm>.",
+				  file, line, args[0]);
+			ret = -1;
+			goto end;
+		}
+		while (*(args[cur_arg])) {
+			int retval = comp_append_algo(&comp->algos_res, args[cur_arg]);
+			if (retval) {
+				if (retval < 0)
+					memprintf(err, "'%s' : '%s' is not a supported algorithm.",
+						  args[0], args[cur_arg]);
+				else
+					memprintf(err, "'%s' : out of memory while parsing algo '%s'.",
+						  args[0], args[cur_arg]);
+				ret = -1;
+				goto end;
+			}
+
+			if (proxy->comp->algos_res->init(&ctx, 9) == 0)
+				proxy->comp->algos_res->end(&ctx);
+			else {
+				memprintf(err, "'%s' : Can't init '%s' algorithm.",
+					  args[0], args[cur_arg]);
+				ret = -1;
+				goto end;
+			}
+			cur_arg++;
+			continue;
+		}
+	}
+	else if (strcmp(args[1], "algo-req") == 0) {
+		struct comp_ctx *ctx;
+		int retval = comp_append_algo(&comp->algo_req, args[2]);
+
+		if (retval) {
+			if (retval < 0)
+				memprintf(err, "'%s' : '%s' is not a supported algorithm.",
+				    args[0], args[2]);
+			else
+				memprintf(err, "'%s' : out of memory while parsing algo '%s'.",
+				    args[0], args[2]);
+			ret = -1;
+			goto end;
+		}
+
+		if (proxy->comp->algo_req->init(&ctx, 9) == 0)
+			proxy->comp->algo_req->end(&ctx);
+		else {
+			memprintf(err, "'%s' : Can't init '%s' algorithm.",
+			    args[0], args[2]);
+			ret = -1;
+			goto end;
+		}
+	}
+	else if (strcmp(args[1], "offload") == 0) {
+		if (proxy->cap & PR_CAP_DEF) {
+			memprintf(err, "'%s' : '%s' ignored in 'defaults' section.",
+				  args[0], args[1]);
+			ret = 1;
+		}
+		comp->flags |= COMP_FL_OFFLOAD;
+	}
+	else if (strcmp(args[1], "type") == 0 || strcmp(args[1], "type-res") == 0) {
+		int cur_arg = 2;
+
+		if (!*args[cur_arg]) {
+			memprintf(err, "'%s' expects <type>.", args[0]);
+			ret = -1;
+			goto end;
+		}
+		while (*(args[cur_arg])) {
+			if (comp_append_type(&comp->types_res, args[cur_arg])) {
+				memprintf(err, "'%s': out of memory.", args[0]);
+				ret = -1;
+				goto end;
+			}
+			cur_arg++;
+			continue;
+		}
+	}
+	else if (strcmp(args[1], "type-req") == 0) {
+		int cur_arg = 2;
+
+		if (!*args[cur_arg]) {
+			memprintf(err, "'%s' expects <type>.", args[0]);
+			ret = -1;
+			goto end;
+		}
+		while (*(args[cur_arg])) {
+			if (comp_append_type(&comp->types_req, args[cur_arg])) {
+				memprintf(err, "'%s': out of memory.", args[0]);
+				ret = -1;
+				goto end;
+			}
+			cur_arg++;
+			continue;
+		}
+	}
+	else if (strcmp(args[1], "direction") == 0) {
+		if (!args[2]) {
+			memprintf(err, "'%s' expects 'request', 'response', or 'both'.", args[0]);
+			ret = -1;
+			goto end;
+		}
+		if (strcmp(args[2], "request") == 0) {
+			comp->flags &= ~COMP_FL_DIR_RES;
+			comp->flags |= COMP_FL_DIR_REQ;
+		} else if (strcmp(args[2], "response") == 0) {
+			comp->flags &= COMP_FL_DIR_REQ;
+			comp->flags |= COMP_FL_DIR_RES;
+		} else if (strcmp(args[2], "both") == 0)
+			comp->flags |= COMP_FL_DIR_REQ | COMP_FL_DIR_RES;
+		else {
+			memprintf(err, "'%s' expects 'request', 'response', or 'both'.", args[0]);
+			ret = -1;
+			goto end;
+		}
+	}
+	else {
+		memprintf(err, "'%s' expects 'algo', 'type' 'direction' or 'offload'",
+			  args[0]);
+		ret = -1;
+		goto end;
+	}
+
+  end:
+	return ret;
+}
+
+static int
+parse_http_comp_flt(char **args, int *cur_arg, struct proxy *px,
+                    struct flt_conf *fconf, char **err, void *private)
+{
+	struct flt_conf *fc, *back;
+
+	list_for_each_entry_safe(fc, back, &px->filter_configs, list) {
+		if (fc->id == http_comp_flt_id) {
+			memprintf(err, "%s: Proxy supports only one compression filter\n", px->id);
+			return -1;
+		}
+	}
+
+	fconf->id   = http_comp_flt_id;
+	fconf->conf = NULL;
+	fconf->ops  = &comp_ops;
+	(*cur_arg)++;
+
+	return 0;
+}
+
+
+int
+check_implicit_http_comp_flt(struct proxy *proxy)
+{
+	struct flt_conf *fconf;
+	int explicit = 0;
+	int comp = 0;
+	int err = 0;
+
+	if (proxy->comp == NULL)
+		goto end;
+	if (!LIST_ISEMPTY(&proxy->filter_configs)) {
+		list_for_each_entry(fconf, &proxy->filter_configs, list) {
+			if (fconf->id == http_comp_flt_id)
+				comp = 1;
+			else if (fconf->id == cache_store_flt_id) {
+				if (comp) {
+					ha_alert("config: %s '%s': unable to enable the compression filter "
+						 "before any cache filter.\n",
+						 proxy_type_str(proxy), proxy->id);
+					err++;
+					goto end;
+				}
+			}
+			else if (fconf->id == fcgi_flt_id)
+				continue;
+			else
+				explicit = 1;
+		}
+	}
+	if (comp)
+		goto end;
+	else if (explicit) {
+		ha_alert("config: %s '%s': require an explicit filter declaration to use "
+			 "HTTP compression\n", proxy_type_str(proxy), proxy->id);
+		err++;
+		goto end;
+	}
+
+	/* Implicit declaration of the compression filter is always the last
+	 * one */
+	fconf = calloc(1, sizeof(*fconf));
+	if (!fconf) {
+		ha_alert("config: %s '%s': out of memory\n",
+			 proxy_type_str(proxy), proxy->id);
+		err++;
+		goto end;
+	}
+	fconf->id   = http_comp_flt_id;
+	fconf->conf = NULL;
+	fconf->ops  = &comp_ops;
+	LIST_APPEND(&proxy->filter_configs, &fconf->list);
+ end:
+	return err;
+}
+
+/*
+ * boolean, returns true if compression is used (either gzip or deflate) in the
+ * response.
+ */
+static int
+smp_fetch_res_comp(const struct arg *args, struct sample *smp, const char *kw,
+		   void *private)
+{
+	struct http_txn *txn = smp->strm ? smp->strm->txn : NULL;
+
+	smp->data.type = SMP_T_BOOL;
+	smp->data.u.sint = (txn && (txn->rsp.flags & HTTP_MSGF_COMPRESSING));
+	return 1;
+}
+
+/*
+ * string, returns algo
+ */
+static int
+smp_fetch_res_comp_algo(const struct arg *args, struct sample *smp,
+			const char *kw, void *private)
+{
+	struct http_txn   *txn = smp->strm ? smp->strm->txn : NULL;
+	struct filter     *filter;
+	struct comp_state *st;
+
+	if (!txn || !(txn->rsp.flags & HTTP_MSGF_COMPRESSING))
+		return 0;
+
+	list_for_each_entry(filter, &strm_flt(smp->strm)->filters, list) {
+		if (FLT_ID(filter) != http_comp_flt_id)
+			continue;
+
+		if (!(st = filter->ctx))
+			break;
+
+		smp->data.type = SMP_T_STR;
+		smp->flags = SMP_F_CONST;
+		smp->data.u.str.area = st->comp_algo[COMP_DIR_RES]->cfg_name;
+		smp->data.u.str.data = st->comp_algo[COMP_DIR_RES]->cfg_name_len;
+		return 1;
+	}
+	return 0;
+}
+
+/* Declare the config parser for "compression" keyword */
+static struct cfg_kw_list cfg_kws = {ILH, {
+		{ CFG_LISTEN, "compression", parse_compression_options },
+		{ 0, NULL, NULL },
+	}
+};
+
+INITCALL1(STG_REGISTER, cfg_register_keywords, &cfg_kws);
+
+/* Declare the filter parser for "compression" keyword */
+static struct flt_kw_list filter_kws = { "COMP", { }, {
+		{ "compression", parse_http_comp_flt, NULL },
+		{ NULL, NULL, NULL },
+	}
+};
+
+INITCALL1(STG_REGISTER, flt_register_keywords, &filter_kws);
+
+/* Note: must not be declared <const> as its list will be overwritten */
+static struct sample_fetch_kw_list sample_fetch_keywords = {ILH, {
+		{ "res.comp",      smp_fetch_res_comp,      0, NULL, SMP_T_BOOL, SMP_USE_HRSHP },
+		{ "res.comp_algo", smp_fetch_res_comp_algo, 0, NULL, SMP_T_STR, SMP_USE_HRSHP },
+		{ /* END */ },
+	}
+};
+
+INITCALL1(STG_REGISTER, sample_register_fetches, &sample_fetch_keywords);