From 98de5697e671d7ee05e8e847a5ea32e3bfa0c9e3 Mon Sep 17 00:00:00 2001
From: Richard Fuchs <rfuchs@sipwise.com>
Date: Mon, 10 Dec 2018 03:41:22 -0500
Subject: [PATCH] TT#48650 use constant string hashing for string lookups

To avoid repeated strcmp()s and make use of switch()'s optimised binary
lookup, we employ a second build step that preprocesses certain .c files
and uses gperf to substitute pseudomacros with their respective constant
hash value.

Change-Id: Id89c4728a0fc7aa911691d4dd1ba8e7b3916a983
---
 .gitignore               |   1 +
 daemon/Makefile          |   4 +-
 daemon/call_interfaces.c | 265 +++++++++++++++++++++++----------------
 daemon/control_ng.c      | 126 ++++++++++---------
 daemon/sdp.c             | 135 ++++++++++----------
 debian/control           |   1 +
 lib/common.Makefile      |   7 +-
 t/.gitignore             |   1 +
 t/Makefile               |  27 ++--
 t/const_str_hash-test.c  |  35 ++++++
 utils/const_str_hash     |  73 +++++++++++
 11 files changed, 425 insertions(+), 250 deletions(-)
 create mode 100644 t/const_str_hash-test.c
 create mode 100755 utils/const_str_hash

diff --git a/.gitignore b/.gitignore
index 326821191..1d012c677 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 .*.sw?
+*.strhash.c
diff --git a/daemon/Makefile b/daemon/Makefile
index 347e15724..d30a8caed 100644
--- a/daemon/Makefile
+++ b/daemon/Makefile
@@ -113,8 +113,8 @@ LDLIBS+=	$(bcg729_lib)
 endif
 
 SRCS=		main.c kernel.c poller.c aux.c control_tcp.c streambuf.c call.c control_udp.c redis.c \
-		bencode.c cookie_cache.c udp_listener.c control_ng.c sdp.c stun.c rtcp.c \
-		crypto.c rtp.c call_interfaces.c dtls.c log.c cli.c graphite.c ice.c socket.c \
+		bencode.c cookie_cache.c udp_listener.c control_ng.strhash.c sdp.strhash.c stun.c rtcp.c \
+		crypto.c rtp.c call_interfaces.strhash.c dtls.c log.c cli.c graphite.c ice.c socket.c \
 		media_socket.c homer.c recording.c statistics.c cdr.c ssrc.c iptables.c tcp_listener.c \
 		codec.c load.c dtmf.c
 LIBSRCS=	loglib.c auxlib.c rtplib.c str.c
diff --git a/daemon/call_interfaces.c b/daemon/call_interfaces.c
index c2d64799d..9d9910293 100644
--- a/daemon/call_interfaces.c
+++ b/daemon/call_interfaces.c
@@ -500,24 +500,41 @@ INLINE char *bencode_get_alt(bencode_item_t *i, const char *one, const char *two
 }
 
 INLINE void ng_sdes_option(struct sdp_ng_flags *out, str *s, void *dummy) {
-	if (!str_cmp(s, "no") || !str_cmp(s, "off") || !str_cmp(s, "disabled")
-			|| !str_cmp(s, "disable"))
-		out->sdes_off = 1;
-	else if (!str_cmp(s, "unencrypted_srtp") || !str_cmp(s, "UNENCRYPTED_SRTP"))
-		out->sdes_unencrypted_srtp = 1;
-	else if (!str_cmp(s, "unencrypted_srtcp") || !str_cmp(s, "UNENCRYPTED_SRTCP"))
-		out->sdes_unencrypted_srtcp = 1;
-	else if (!str_cmp(s, "unauthenticated_srtp") || !str_cmp(s, "UNAUTHENTICATED_SRTP"))
-		out->sdes_unauthenticated_srtp = 1;
-	else if (!str_cmp(s, "encrypted_srtp") || !str_cmp(s, "ENCRYPTED_SRTP"))
-		out->sdes_encrypted_srtp = 1;
-	else if (!str_cmp(s, "encrypted_srtcp") || !str_cmp(s, "ENCRYPTED_SRTCP"))
-		out->sdes_encrypted_srtcp = 1;
-	else if (!str_cmp(s, "authenticated_srtp") || !str_cmp(s, "AUTHENTICATED_SRTP"))
-		out->sdes_authenticated_srtp = 1;
-	else
-		ilog(LOG_WARN, "Unknown 'SDES' flag encountered: '"STR_FORMAT"'",
-				STR_FMT(s));
+	switch (__csh_lookup(s)) {
+		case CSH_LOOKUP("no"):
+		case CSH_LOOKUP("off"):
+		case CSH_LOOKUP("disabled"):
+		case CSH_LOOKUP("disable"):
+			out->sdes_off = 1;
+			break;
+		case CSH_LOOKUP("unencrypted_srtp"):
+		case CSH_LOOKUP("UNENCRYPTED_SRTP"):
+			out->sdes_unencrypted_srtp = 1;
+			break;
+		case CSH_LOOKUP("unencrypted_srtcp"):
+		case CSH_LOOKUP("UNENCRYPTED_SRTCP"):
+			out->sdes_unencrypted_srtcp = 1;
+			break;
+		case CSH_LOOKUP("unauthenticated_srtp"):
+		case CSH_LOOKUP("UNAUTHENTICATED_SRTP"):
+			out->sdes_unauthenticated_srtp = 1;
+			break;
+		case CSH_LOOKUP("encrypted_srtp"):
+		case CSH_LOOKUP("ENCRYPTED_SRTP"):
+			out->sdes_encrypted_srtp = 1;
+			break;
+		case CSH_LOOKUP("encrypted_srtcp"):
+		case CSH_LOOKUP("ENCRYPTED_SRTCP"):
+			out->sdes_encrypted_srtcp = 1;
+			break;
+		case CSH_LOOKUP("authenticated_srtp"):
+		case CSH_LOOKUP("AUTHENTICATED_SRTP"):
+			out->sdes_authenticated_srtp = 1;
+			break;
+		default:
+			ilog(LOG_WARN, "Unknown 'SDES' flag encountered: '"STR_FORMAT"'",
+					STR_FMT(s));
+	}
 }
 
 
@@ -535,19 +552,26 @@ static void call_ng_flags_list(struct sdp_ng_flags *out, bencode_item_t *input,
 	}
 }
 static void call_ng_flags_rtcp_mux(struct sdp_ng_flags *out, str *s, void *dummy) {
-	if (!str_cmp(s, "offer"))
-		out->rtcp_mux_offer = 1;
-	else if (!str_cmp(s, "require"))
-		out->rtcp_mux_require = 1;
-	else if (!str_cmp(s, "demux"))
-		out->rtcp_mux_demux = 1;
-	else if (!str_cmp(s, "accept"))
-		out->rtcp_mux_accept = 1;
-	else if (!str_cmp(s, "reject"))
-		out->rtcp_mux_reject = 1;
-	else
-		ilog(LOG_WARN, "Unknown 'rtcp-mux' flag encountered: '" STR_FORMAT "'",
-				STR_FMT(s));
+	switch (__csh_lookup(s)) {
+		case CSH_LOOKUP("offer"):
+			out->rtcp_mux_offer = 1;
+			break;
+		case CSH_LOOKUP("require"):
+			out->rtcp_mux_require = 1;
+			break;
+		case CSH_LOOKUP("demux"):
+			out->rtcp_mux_demux = 1;
+			break;
+		case CSH_LOOKUP("accept"):
+			out->rtcp_mux_accept = 1;
+			break;
+		case CSH_LOOKUP("reject"):
+			out->rtcp_mux_reject = 1;
+			break;
+		default:
+			ilog(LOG_WARN, "Unknown 'rtcp-mux' flag encountered: '" STR_FORMAT "'",
+					STR_FMT(s));
+	}
 }
 static void call_ng_flags_replace(struct sdp_ng_flags *out, str *s, void *dummy) {
 	str_hyphenate(s);
@@ -590,65 +614,84 @@ INLINE int call_ng_flags_prefix(struct sdp_ng_flags *out, str *s_ori, const char
 static void call_ng_flags_flags(struct sdp_ng_flags *out, str *s, void *dummy) {
 	str_hyphenate(s);
 
-	// XXX use internal hash tables for these
-	if (!str_cmp(s, "trust-address"))
-		out->trust_address = 1;
-	else if (!str_cmp(s, "SIP-source-address"))
-		out->trust_address = 0;
-	else if (!str_cmp(s, "asymmetric"))
-		out->asymmetric = 1;
-	else if (!str_cmp(s, "no-redis-update"))
-		out->no_redis_update = 1;
-	else if (!str_cmp(s, "unidirectional"))
-		out->unidirectional = 1;
-	else if (!str_cmp(s, "strict-source"))
-		out->strict_source = 1;
-	else if (!str_cmp(s, "media-handover"))
-		out->media_handover = 1;
-	else if (!str_cmp(s, "reset"))
-		out->reset = 1;
-	else if (!str_cmp(s, "all"))
-		out->all = 1;
-	else if (!str_cmp(s, "fragment"))
-		out->fragment = 1;
-	else if (!str_cmp(s, "port-latching"))
-		out->port_latching = 1;
-	else if (!str_cmp(s, "generate-mid"))
-		out->generate_mid = 1;
-	else if (!str_cmp(s, "record-call"))
-		out->record_call = 1;
-	else if (!str_cmp(s, "no-rtcp-attribute"))
-		out->no_rtcp_attr = 1;
-	else if (!str_cmp(s, "full-rtcp-attribute"))
-		out->full_rtcp_attr = 1;
-	else if (!str_cmp(s, "loop-protect"))
-		out->loop_protect = 1;
-	else if (!str_cmp(s, "always-transcode"))
-		out->always_transcode = 1;
-	else if (!str_cmp(s, "asymmetric-codecs"))
-		out->asymmetric_codecs = 1;
-	else if (!str_cmp(s, "pad-crypto"))
-		out->pad_crypto = 1;
-	else {
-		// handle values aliases from other dictionaries
-		if (call_ng_flags_prefix(out, s, "SDES-", ng_sdes_option, NULL))
-			return;
-		if (call_ng_flags_prefix(out, s, "codec-strip-", call_ng_flags_codec_ht, out->codec_strip))
-			return;
-		if (call_ng_flags_prefix(out, s, "codec-offer-", call_ng_flags_codec_list, &out->codec_offer))
-			return;
+	switch (__csh_lookup(s)) {
+		case CSH_LOOKUP("trust-address"):
+			out->trust_address = 1;
+			break;
+		case CSH_LOOKUP("SIP-source-address"):
+			out->trust_address = 0;
+			break;
+		case CSH_LOOKUP("asymmetric"):
+			out->asymmetric = 1;
+			break;
+		case CSH_LOOKUP("no-redis-update"):
+			out->no_redis_update = 1;
+			break;
+		case CSH_LOOKUP("unidirectional"):
+			out->unidirectional = 1;
+			break;
+		case CSH_LOOKUP("strict-source"):
+			out->strict_source = 1;
+			break;
+		case CSH_LOOKUP("media-handover"):
+			out->media_handover = 1;
+			break;
+		case CSH_LOOKUP("reset"):
+			out->reset = 1;
+			break;
+		case CSH_LOOKUP("all"):
+			out->all = 1;
+			break;
+		case CSH_LOOKUP("fragment"):
+			out->fragment = 1;
+			break;
+		case CSH_LOOKUP("port-latching"):
+			out->port_latching = 1;
+			break;
+		case CSH_LOOKUP("generate-mid"):
+			out->generate_mid = 1;
+			break;
+		case CSH_LOOKUP("record-call"):
+			out->record_call = 1;
+			break;
+		case CSH_LOOKUP("no-rtcp-attribute"):
+			out->no_rtcp_attr = 1;
+			break;
+		case CSH_LOOKUP("full-rtcp-attribute"):
+			out->full_rtcp_attr = 1;
+			break;
+		case CSH_LOOKUP("loop-protect"):
+			out->loop_protect = 1;
+			break;
+		case CSH_LOOKUP("always-transcode"):
+			out->always_transcode = 1;
+			break;
+		case CSH_LOOKUP("asymmetric-codecs"):
+			out->asymmetric_codecs = 1;
+			break;
+		case CSH_LOOKUP("pad-crypto"):
+			out->pad_crypto = 1;
+			break;
+		default:
+			// handle values aliases from other dictionaries
+			if (call_ng_flags_prefix(out, s, "SDES-", ng_sdes_option, NULL))
+				return;
+			if (call_ng_flags_prefix(out, s, "codec-strip-", call_ng_flags_codec_ht, out->codec_strip))
+				return;
+			if (call_ng_flags_prefix(out, s, "codec-offer-", call_ng_flags_codec_list, &out->codec_offer))
+				return;
 #ifdef WITH_TRANSCODING
-		if (call_ng_flags_prefix(out, s, "transcode-", call_ng_flags_codec_list, &out->codec_transcode))
-			return;
-		if (call_ng_flags_prefix(out, s, "codec-transcode-", call_ng_flags_codec_list,
-					&out->codec_transcode))
-			return;
-		if (call_ng_flags_prefix(out, s, "codec-mask-", call_ng_flags_codec_ht, out->codec_mask))
-			return;
+			if (call_ng_flags_prefix(out, s, "transcode-", call_ng_flags_codec_list, &out->codec_transcode))
+				return;
+			if (call_ng_flags_prefix(out, s, "codec-transcode-", call_ng_flags_codec_list,
+						&out->codec_transcode))
+				return;
+			if (call_ng_flags_prefix(out, s, "codec-mask-", call_ng_flags_codec_ht, out->codec_mask))
+				return;
 #endif
 
-		ilog(LOG_WARN, "Unknown flag encountered: '" STR_FORMAT "'",
-				STR_FMT(s));
+			ilog(LOG_WARN, "Unknown flag encountered: '" STR_FORMAT "'",
+					STR_FMT(s));
 	}
 }
 static void call_ng_process_flags(struct sdp_ng_flags *out, bencode_item_t *input) {
@@ -682,27 +725,39 @@ static void call_ng_process_flags(struct sdp_ng_flags *out, bencode_item_t *inpu
 	}
 
 	if (bencode_dictionary_get_str(input, "ICE", &s)) {
-		if (!str_cmp(&s, "remove"))
-			out->ice_remove = 1;
-		else if (!str_cmp(&s, "force"))
-			out->ice_force = 1;
-		else if (!str_cmp(&s, "force_relay") || !str_cmp(&s, "force-relay")
-				|| !str_cmp(&s, "force relay"))
-			out->ice_force_relay = 1;
-		else
-			ilog(LOG_WARN, "Unknown 'ICE' flag encountered: '"STR_FORMAT"'",
-					STR_FMT(&s));
+		switch (__csh_lookup(&s)) {
+			case CSH_LOOKUP("remove"):
+				out->ice_remove = 1;
+				break;
+			case CSH_LOOKUP("force"):
+				out->ice_force = 1;
+				break;
+			case CSH_LOOKUP("force_relay"):
+			case CSH_LOOKUP("force-relay"):
+			case CSH_LOOKUP("force relay"):
+				out->ice_force_relay = 1;
+				break;
+			default:
+				ilog(LOG_WARN, "Unknown 'ICE' flag encountered: '"STR_FORMAT"'",
+						STR_FMT(&s));
+		}
 	}
 
 	if (bencode_dictionary_get_str(input, "DTLS", &s)) {
-		if (!str_cmp(&s, "passive"))
-			out->dtls_passive = 1;
-		else if (!str_cmp(&s, "no") || !str_cmp(&s, "off") || !str_cmp(&s, "disabled")
-				|| !str_cmp(&s, "disable"))
-			out->dtls_off = 1;
-		else
-			ilog(LOG_WARN, "Unknown 'DTLS' flag encountered: '"STR_FORMAT"'",
-					STR_FMT(&s));
+		switch (__csh_lookup(&s)) {
+			case CSH_LOOKUP("passive"):
+				out->dtls_passive = 1;
+				break;
+			case CSH_LOOKUP("no"):
+			case CSH_LOOKUP("off"):
+			case CSH_LOOKUP("disabled"):
+			case CSH_LOOKUP("disable"):
+				out->dtls_off = 1;
+				break;
+			default:
+				ilog(LOG_WARN, "Unknown 'DTLS' flag encountered: '"STR_FORMAT"'",
+						STR_FMT(&s));
+		}
 	}
 
 	call_ng_flags_list(out, input, "rtcp-mux", call_ng_flags_rtcp_mux, NULL);
diff --git a/daemon/control_ng.c b/daemon/control_ng.c
index 8a279afa8..59c4a0efa 100644
--- a/daemon/control_ng.c
+++ b/daemon/control_ng.c
@@ -184,57 +184,59 @@ static void control_ng_incoming(struct obj *obj, str *buf, const endpoint_t *sin
 	// start command timer
 	gettimeofday(&cmd_start, NULL);
 
-	if (!str_cmp(&cmd, "ping")) {
-		resultstr = "pong";
-		g_atomic_int_inc(&cur->ping);
-	}
-	else if (!str_cmp(&cmd, "offer")) {
-		errstr = call_offer_ng(dict, resp, addr, sin);
-		g_atomic_int_inc(&cur->offer);
-	}
-	else if (!str_cmp(&cmd, "answer")) {
-		errstr = call_answer_ng(dict, resp);
-		g_atomic_int_inc(&cur->answer);
-	}
-	else if (!str_cmp(&cmd, "delete")) {
-		errstr = call_delete_ng(dict, resp);
-		g_atomic_int_inc(&cur->delete);
-	}
-	else if (!str_cmp(&cmd, "query")) {
-		errstr = call_query_ng(dict, resp);
-		g_atomic_int_inc(&cur->query);
-	}
-	else if (!str_cmp(&cmd, "list")) {
-	    errstr = call_list_ng(dict, resp);
-	    g_atomic_int_inc(&cur->list);
-	}
-	else if (!str_cmp(&cmd, "start recording")) {
-		errstr = call_start_recording_ng(dict, resp);
-		g_atomic_int_inc(&cur->start_recording);
-	}
-	else if (!str_cmp(&cmd, "stop recording")) {
-		errstr = call_stop_recording_ng(dict, resp);
-		g_atomic_int_inc(&cur->stop_recording);
-	}
-	else if (!str_cmp(&cmd, "block DTMF")) {
-		errstr = call_block_dtmf_ng(dict, resp);
-		g_atomic_int_inc(&cur->block_dtmf);
-	}
-	else if (!str_cmp(&cmd, "unblock DTMF")) {
-		errstr = call_unblock_dtmf_ng(dict, resp);
-		g_atomic_int_inc(&cur->unblock_dtmf);
-	}
-	else if (!str_cmp(&cmd, "block media")) {
-		errstr = call_block_media_ng(dict, resp);
-		g_atomic_int_inc(&cur->block_media);
-	}
-	else if (!str_cmp(&cmd, "unblock media")) {
-		errstr = call_unblock_media_ng(dict, resp);
-		g_atomic_int_inc(&cur->unblock_media);
-	}
-	else
-	{
-		errstr = "Unrecognized command";
+	int cmdcode = __csh_lookup(&cmd);
+
+	switch (cmdcode) {
+		case CSH_LOOKUP("ping"):
+			resultstr = "pong";
+			g_atomic_int_inc(&cur->ping);
+			break;
+		case CSH_LOOKUP("offer"):
+			errstr = call_offer_ng(dict, resp, addr, sin);
+			g_atomic_int_inc(&cur->offer);
+			break;
+		case CSH_LOOKUP("answer"):
+			errstr = call_answer_ng(dict, resp);
+			g_atomic_int_inc(&cur->answer);
+			break;
+		case CSH_LOOKUP("delete"):
+			errstr = call_delete_ng(dict, resp);
+			g_atomic_int_inc(&cur->delete);
+			break;
+		case CSH_LOOKUP("query"):
+			errstr = call_query_ng(dict, resp);
+			g_atomic_int_inc(&cur->query);
+			break;
+		case CSH_LOOKUP("list"):
+			errstr = call_list_ng(dict, resp);
+			g_atomic_int_inc(&cur->list);
+			break;
+		case CSH_LOOKUP("start recording"):
+			errstr = call_start_recording_ng(dict, resp);
+			g_atomic_int_inc(&cur->start_recording);
+			break;
+		case CSH_LOOKUP("stop recording"):
+			errstr = call_stop_recording_ng(dict, resp);
+			g_atomic_int_inc(&cur->stop_recording);
+			break;
+		case CSH_LOOKUP("block DTMF"):
+			errstr = call_block_dtmf_ng(dict, resp);
+			g_atomic_int_inc(&cur->block_dtmf);
+			break;
+		case CSH_LOOKUP("unblock DTMF"):
+			errstr = call_unblock_dtmf_ng(dict, resp);
+			g_atomic_int_inc(&cur->unblock_dtmf);
+			break;
+		case CSH_LOOKUP("block media"):
+			errstr = call_block_media_ng(dict, resp);
+			g_atomic_int_inc(&cur->block_media);
+			break;
+		case CSH_LOOKUP("unblock media"):
+			errstr = call_unblock_media_ng(dict, resp);
+			g_atomic_int_inc(&cur->unblock_media);
+			break;
+		default:
+			errstr = "Unrecognized command";
 	}
 
 	// stop command timer
@@ -248,15 +250,19 @@ static void control_ng_incoming(struct obj *obj, str *buf, const endpoint_t *sin
 	bencode_dictionary_add_string(resp, "result", resultstr);
 
 	// update interval statistics
-	if (!str_cmp(&cmd, "offer")) {
-		atomic64_inc(&rtpe_statsps.offers);
-		timeval_update_request_time(&rtpe_totalstats_interval.offer, &cmd_process_time);
-	} else if (!str_cmp(&cmd, "answer")) {
-		atomic64_inc(&rtpe_statsps.answers);
-		timeval_update_request_time(&rtpe_totalstats_interval.answer, &cmd_process_time);
-	} else if (!str_cmp(&cmd, "delete")) {
-		atomic64_inc(&rtpe_statsps.deletes);
-		timeval_update_request_time(&rtpe_totalstats_interval.delete, &cmd_process_time);
+	switch (cmdcode) {
+		case CSH_LOOKUP("offer"):
+			atomic64_inc(&rtpe_statsps.offers);
+			timeval_update_request_time(&rtpe_totalstats_interval.offer, &cmd_process_time);
+			break;
+		case CSH_LOOKUP("answer"):
+			atomic64_inc(&rtpe_statsps.answers);
+			timeval_update_request_time(&rtpe_totalstats_interval.answer, &cmd_process_time);
+			break;
+		case CSH_LOOKUP("delete"):
+			atomic64_inc(&rtpe_statsps.deletes);
+			timeval_update_request_time(&rtpe_totalstats_interval.delete, &cmd_process_time);
+			break;
 	}
 
 	goto send_resp;
diff --git a/daemon/sdp.c b/daemon/sdp.c
index e0ab9e6b0..f0fb9e3ad 100644
--- a/daemon/sdp.c
+++ b/daemon/sdp.c
@@ -793,84 +793,81 @@ static int parse_attribute(struct sdp_attribute *a) {
 	}
 
 	ret = 0;
-	switch (a->name.len) {
-		case 3:
-			if (!str_cmp(&a->name, "mid"))
-				a->attr = ATTR_MID;
+	switch (__csh_lookup(&a->name)) {
+		case CSH_LOOKUP("mid"):
+			a->attr = ATTR_MID;
 			break;
-		case 4:
-			if (!str_cmp(&a->name, "rtcp"))
-				ret = parse_attribute_rtcp(a);
-			else if (!str_cmp(&a->name, "ssrc"))
-				ret = parse_attribute_ssrc(a);
-			else if (!str_cmp(&a->name, "fmtp"))
-				ret = parse_attribute_fmtp(a);
+		case CSH_LOOKUP("rtcp"):
+			ret = parse_attribute_rtcp(a);
 			break;
-		case 5:
-			if (!str_cmp(&a->name, "group"))
-				ret = parse_attribute_group(a);
-			else if (!str_cmp(&a->name, "setup"))
-				ret = parse_attribute_setup(a);
-			else if (!str_cmp(&a->name, "ptime"))
-				a->attr = ATTR_PTIME;
+		case CSH_LOOKUP("ssrc"):
+			ret = parse_attribute_ssrc(a);
 			break;
-		case 6:
-			if (!str_cmp(&a->name, "crypto"))
-				ret = parse_attribute_crypto(a);
-			else if (!str_cmp(&a->name, "extmap"))
-				a->attr = ATTR_EXTMAP;
-			else if (!str_cmp(&a->name, "rtpmap"))
-				ret = parse_attribute_rtpmap(a);
+		case CSH_LOOKUP("fmtp"):
+			ret = parse_attribute_fmtp(a);
 			break;
-		case 7:
-			if (!str_cmp(&a->name, "ice-pwd"))
-				a->attr = ATTR_ICE_PWD;
+		case CSH_LOOKUP("group"):
+			ret = parse_attribute_group(a);
 			break;
-		case 8:
-			switch (a->name.s[0]) {
-				case 'i':
-					if (!str_cmp(&a->name, "ice-lite"))
-						a->attr = ATTR_ICE_LITE;
-					else if (!str_cmp(&a->name, "inactive"))
-						a->attr = ATTR_INACTIVE;
-					break;
-				case 's':
-					if (!str_cmp(&a->name, "sendrecv"))
-						a->attr = ATTR_SENDRECV;
-					else if (!str_cmp(&a->name, "sendonly"))
-						a->attr = ATTR_SENDONLY;
-					break;
-				case 'r':
-					if (!str_cmp(&a->name, "recvonly"))
-						a->attr = ATTR_RECVONLY;
-					if (!str_cmp(&a->name, "rtcp-mux"))
-						a->attr = ATTR_RTCP_MUX;
-					break;
-			}
+		case CSH_LOOKUP("setup"):
+			ret = parse_attribute_setup(a);
+			break;
+		case CSH_LOOKUP("ptime"):
+			a->attr = ATTR_PTIME;
+			break;
+		case CSH_LOOKUP("crypto"):
+			ret = parse_attribute_crypto(a);
+			break;
+		case CSH_LOOKUP("extmap"):
+			a->attr = ATTR_EXTMAP;
+			break;
+		case CSH_LOOKUP("rtpmap"):
+			ret = parse_attribute_rtpmap(a);
+			break;
+		case CSH_LOOKUP("ice-pwd"):
+			a->attr = ATTR_ICE_PWD;
+			break;
+		case CSH_LOOKUP("ice-lite"):
+			a->attr = ATTR_ICE_LITE;
+			break;
+		case CSH_LOOKUP("inactive"):
+			a->attr = ATTR_INACTIVE;
+			break;
+		case CSH_LOOKUP("sendrecv"):
+			a->attr = ATTR_SENDRECV;
+			break;
+		case CSH_LOOKUP("sendonly"):
+			a->attr = ATTR_SENDONLY;
+			break;
+		case CSH_LOOKUP("recvonly"):
+			a->attr = ATTR_RECVONLY;
+			break;
+		case CSH_LOOKUP("rtcp-mux"):
+			a->attr = ATTR_RTCP_MUX;
+			break;
+		case CSH_LOOKUP("candidate"):
+			ret = parse_attribute_candidate(a);
+			break;
+		case CSH_LOOKUP("ice-ufrag"):
+			a->attr = ATTR_ICE_UFRAG;
+			break;
+		case CSH_LOOKUP("rtpengine"):
+			a->attr = ATTR_RTPENGINE;
+			break;
+		case CSH_LOOKUP("ice-options"):
+			a->attr = ATTR_ICE_OPTIONS;
 			break;
-		case 9:
-			if (!str_cmp(&a->name, "candidate"))
-				ret = parse_attribute_candidate(a);
-			else if (!str_cmp(&a->name, "ice-ufrag"))
-				a->attr = ATTR_ICE_UFRAG;
-			else if (!str_cmp(&a->name, "rtpengine"))
-				a->attr = ATTR_RTPENGINE;
+		case CSH_LOOKUP("fingerprint"):
+			ret = parse_attribute_fingerprint(a);
 			break;
-		case 11:
-			if (!str_cmp(&a->name, "ice-options"))
-				a->attr = ATTR_ICE_OPTIONS;
-			else if (!str_cmp(&a->name, "fingerprint"))
-				ret = parse_attribute_fingerprint(a);
+		case CSH_LOOKUP("ice-mismatch"):
+			a->attr = ATTR_ICE;
 			break;
-		case 12:
-			if (!str_cmp(&a->name, "ice-mismatch"))
-				a->attr = ATTR_ICE;
+		case CSH_LOOKUP("remote-candidates"):
+			a->attr = ATTR_ICE;
 			break;
-		case 17:
-			if (!str_cmp(&a->name, "remote-candidates"))
-				a->attr = ATTR_ICE;
-			else if (!str_cmp(&a->name, "end-of-candidates"))
-				a->attr = ATTR_END_OF_CANDIDATES;
+		case CSH_LOOKUP("end-of-candidates"):
+			a->attr = ATTR_END_OF_CANDIDATES;
 			break;
 	}
 
diff --git a/debian/control b/debian/control
index 230e1e4cb..853005e12 100644
--- a/debian/control
+++ b/debian/control
@@ -7,6 +7,7 @@ Standards-Version: 3.9.8
 Build-Depends:
  debhelper (>= 10~),
  default-libmysqlclient-dev | libmysqlclient-dev,
+ gperf,
  iptables-dev (>= 1.4),
  libavcodec-dev (>= 6:10),
  libavfilter-dev (>= 6:10),
diff --git a/lib/common.Makefile b/lib/common.Makefile
index ae63d69a6..d0e925fec 100644
--- a/lib/common.Makefile
+++ b/lib/common.Makefile
@@ -13,7 +13,7 @@ dep:		.depend
 
 clean:
 	rm -f $(OBJS) $(TARGET) $(LIBSRCS) $(DAEMONSRCS) $(ADD_CLEAN) .depend core core.*
-	rm -f fix_frame_channel_layout.h fix_frame_channel_layout-test.[co]
+	rm -f fix_frame_channel_layout.h fix_frame_channel_layout-test.[co] *.strhash.c $(HASHSRCS)
 
 .depend:	$(SRCS) $(LIBSRCS) $(DAEMONSRCS) Makefile
 	$(CC) $(CFLAGS) -M $(SRCS) $(LIBSRCS) $(DAEMONSRCS) | sed -e 's/:/ .depend:/' > .depend
@@ -27,13 +27,16 @@ $(LIBSRCS):	$(patsubst %,../lib/%,$(LIBSRCS))
 		echo '/******** GENERATED FILE ********/' > "$@"
 		cat ../lib/"$@" >> "$@"
 
-$(DAEMONSRCS):	$(patsubst %,../daemon/%,$(DAEMONSRCS))
+$(DAEMONSRCS) $(HASHSRCS):	$(patsubst %,../daemon/%,$(DAEMONSRCS)) $(patsubst %,../daemon/%,$(HASHSRCS))
 		rm -f "$@"
 		echo '/******** GENERATED FILE ********/' > "$@"
 		cat ../daemon/"$@" >> "$@"
 
 resample.c:	fix_frame_channel_layout.h
 
+%.strhash.c:	%.c ../utils/const_str_hash
+	../utils/const_str_hash < $< > $@
+
 fix_frame_channel_layout.h:	../lib/fix_frame_channel_layout-*
 	echo "Looking for usable alternative for $@"; \
 	rm -f fix_frame_channel_layout-test.[co]; \
diff --git a/t/.gitignore b/t/.gitignore
index 0b00585b5..003bc046d 100644
--- a/t/.gitignore
+++ b/t/.gitignore
@@ -44,3 +44,4 @@ transcode-test
 udp_listener.c
 payload-tracker-test
 dtmf.c
+const_str_hash-test.strhash
diff --git a/t/Makefile b/t/Makefile
index 9d53e4775..6b086d953 100644
--- a/t/Makefile
+++ b/t/Makefile
@@ -49,21 +49,21 @@ LDLIBS+=	$(shell pkg-config xmlrpc_util --libs 2> /dev/null)
 LDLIBS+=	-lhiredis
 endif
 
-SRCS=		bitstr-test.c aes-crypt.c payload-tracker-test.c
-ifeq ($(with_transcoding),yes)
-SRCS+=		amr-decode-test.c amr-encode-test.c transcode-test.c
-endif
+SRCS=		bitstr-test.c aes-crypt.c payload-tracker-test.c const_str_hash-test.strhash.c
 LIBSRCS=	loglib.c auxlib.c str.c rtplib.c
-ifeq ($(with_transcoding),yes)
-LIBSRCS+=	codeclib.c resample.c
-endif
 DAEMONSRCS=	crypto.c
+HASHSRCS=
+
 ifeq ($(with_transcoding),yes)
+SRCS+=		amr-decode-test.c amr-encode-test.c transcode-test.c
+LIBSRCS+=	codeclib.c resample.c
 DAEMONSRCS+=	codec.c ssrc.c call.c ice.c aux.c kernel.c media_socket.c stun.c bencode.c socket.c poller.c \
-		dtls.c recording.c statistics.c rtcp.c redis.c iptables.c graphite.c call_interfaces.c sdp.c \
-		rtp.c control_ng.c streambuf.c cookie_cache.c udp_listener.c homer.c load.c cdr.c dtmf.c
+		dtls.c recording.c statistics.c rtcp.c redis.c iptables.c graphite.c \
+		rtp.c streambuf.c cookie_cache.c udp_listener.c homer.c load.c cdr.c dtmf.c
+HASHSRCS+=	call_interfaces.c control_ng.c sdp.c
 endif
-OBJS=		$(SRCS:.c=.o) $(LIBSRCS:.c=.o) $(DAEMONSRCS:.c=.o)
+
+OBJS=		$(SRCS:.c=.o) $(LIBSRCS:.c=.o) $(DAEMONSRCS:.c=.o) $(HASHSRCS:.c=.strhash.o)
 
 COMMONOBJS=	str.o auxlib.o rtplib.o loglib.o
 
@@ -73,7 +73,7 @@ include		.depend
 
 .PHONY:		unit-tests
 
-TESTS=		bitstr-test aes-crypt payload-tracker-test
+TESTS=		bitstr-test aes-crypt payload-tracker-test const_str_hash-test.strhash
 ifeq ($(with_transcoding),yes)
 TESTS+=		amr-decode-test amr-encode-test transcode-test
 endif
@@ -93,7 +93,10 @@ aes-crypt:	aes-crypt.o $(COMMONOBJS) crypto.o
 
 transcode-test:	transcode-test.o $(COMMONOBJS) codeclib.o resample.o codec.o ssrc.o call.o ice.o aux.o \
 	kernel.o media_socket.o stun.o bencode.o socket.o poller.o dtls.o recording.o statistics.o \
-	rtcp.o redis.o iptables.o graphite.o call_interfaces.o sdp.o rtp.o crypto.o control_ng.o \
+	rtcp.o redis.o iptables.o graphite.o call_interfaces.strhash.o sdp.strhash.o rtp.o crypto.o \
+	control_ng.strhash.o \
 	streambuf.o cookie_cache.o udp_listener.o homer.o load.o cdr.o dtmf.o
 
 payload-tracker-test: payload-tracker-test.o $(COMMONOBJS) ssrc.o aux.o auxlib.o rtp.o crypto.o
+
+const_str_hash-test.strhash: const_str_hash-test.strhash.o $(COMMONOBJS)
diff --git a/t/const_str_hash-test.c b/t/const_str_hash-test.c
new file mode 100644
index 000000000..a028a3402
--- /dev/null
+++ b/t/const_str_hash-test.c
@@ -0,0 +1,35 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include "str.h"
+
+static int test_hash(char *p) {
+	str s;
+	str_init(&s, p);
+	switch (__csh_lookup(&s)) {
+		case CSH_LOOKUP("one"):
+			return 1;
+		case CSH_LOOKUP("two"):
+			return 2;
+		case CSH_LOOKUP("dashed-string"):
+			return 3;
+		default:
+			return 0;
+	}
+	// STR_LOOKUP("one") // catch duplicate
+}
+
+static void test(char *p, int exp) {
+	int h = test_hash(p);
+	if (h != exp) {
+		printf("%s:%i test failed: %u != %u (string '%s')\n", __FILE__, __LINE__, h, exp, p);
+		abort();
+	}
+}
+
+int main() {
+	test("one", 1);
+	test("two", 2);
+	test("dashed-string", 3);
+	test("doesn't exist", 0);
+	return 0;
+}
diff --git a/utils/const_str_hash b/utils/const_str_hash
new file mode 100755
index 000000000..e17d3c177
--- /dev/null
+++ b/utils/const_str_hash
@@ -0,0 +1,73 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use IPC::Open2;
+
+print("/******** GENERATED FILE ********/\n");
+
+my $rewritten_input = '';
+my $iter = 0;
+my $keys = '';
+my %key_vals;
+
+# collect keywords and rewrite input file with in lookup keys
+
+while (my $line = <>) {
+	if (!($line =~ s/CSH_LOOKUP\("(.*?)"\)/{}/)) {
+		$rewritten_input .= $line;
+		next;
+	}
+	my $key = $1;
+	if (exists($key_vals{$key})) {
+		$line =~ s/{}/$key_vals{$key}/;
+	}
+	else {
+		$line =~ s/{}/$iter/;
+		$keys .= "$key,$iter\n";
+		$key_vals{$key} = $iter;
+		$iter++;
+	}
+	$rewritten_input .= $line;
+}
+
+# pass collected output to gperf
+
+my ($rd, $wr);
+my $pid = open2($rd, $wr, qw(gperf -t -E -l -c -t -I -H __csh_hash -N __csh_lookup_raw));
+
+# gperf header and keys
+
+print { $wr } "struct __csh_hash_lookup { char *name; int num; };\n%%\n";
+print { $wr } $keys;
+
+# read gperf output
+
+close($wr);
+my $hash_func_code;
+{
+	local $/ = undef;
+	$hash_func_code = <$rd>;
+}
+close($rd);
+waitpid($pid, 0);
+exit(1) if $?;
+
+# convert lookup function to static
+
+$hash_func_code =~ s/(^|\s)struct\s+__csh_hash_lookup\s*\*/\nstatic$&/s;
+
+# print combined output
+
+print $hash_func_code;
+# add convenience function
+print <<END;
+#include "str.h"
+static int __csh_lookup(const str *s) {
+	struct __csh_hash_lookup *h = __csh_lookup_raw(s->s, s->len);
+	if (!h)
+		return -1;
+	return h->num;
+}
+END
+print $rewritten_input;