From: Thomas Pornin <pornin@bolet.org>
Date: Sun, 30 Jul 2017 21:11:26 +0000 (+0200)
Subject: Added Twrch support.
X-Git-Tag: v0.5~1
X-Git-Url: https://bearssl.org/gitweb//home/git/?p=BearSSL;a=commitdiff_plain;h=93681c283077b838ddfc5e276238640c9ed62343;hp=ce1c57909a1b089f1f9a5edafcc76d1b5f8139fc

Added Twrch support.
---

diff --git a/mk/Rules.mk b/mk/Rules.mk
index 694d04e..247c4bb 100644
--- a/mk/Rules.mk
+++ b/mk/Rules.mk
@@ -1,7 +1,7 @@
 # Automatically generated rules. Use 'mkrules.sh' to modify/regenerate.
 
 OBJ = $(OBJDIR)$Pgcm$O $(OBJDIR)$Pccopy$O $(OBJDIR)$Pdec16be$O $(OBJDIR)$Pdec16le$O $(OBJDIR)$Pdec32be$O $(OBJDIR)$Pdec32le$O $(OBJDIR)$Pdec64be$O $(OBJDIR)$Pdec64le$O $(OBJDIR)$Penc16be$O $(OBJDIR)$Penc16le$O $(OBJDIR)$Penc32be$O $(OBJDIR)$Penc32le$O $(OBJDIR)$Penc64be$O $(OBJDIR)$Penc64le$O $(OBJDIR)$Ppemdec$O $(OBJDIR)$Pec_all_m15$O $(OBJDIR)$Pec_all_m31$O $(OBJDIR)$Pec_c25519_i15$O $(OBJDIR)$Pec_c25519_i31$O $(OBJDIR)$Pec_c25519_m15$O $(OBJDIR)$Pec_c25519_m31$O $(OBJDIR)$Pec_curve25519$O $(OBJDIR)$Pec_default$O $(OBJDIR)$Pec_p256_m15$O $(OBJDIR)$Pec_p256_m31$O $(OBJDIR)$Pec_prime_i15$O $(OBJDIR)$Pec_prime_i31$O $(OBJDIR)$Pec_secp256r1$O $(OBJDIR)$Pec_secp384r1$O $(OBJDIR)$Pec_secp521r1$O $(OBJDIR)$Pecdsa_atr$O $(OBJDIR)$Pecdsa_default_sign_asn1$O $(OBJDIR)$Pecdsa_default_sign_raw$O $(OBJDIR)$Pecdsa_default_vrfy_asn1$O $(OBJDIR)$Pecdsa_default_vrfy_raw$O $(OBJDIR)$Pecdsa_i15_bits$O $(OBJDIR)$Pecdsa_i15_sign_asn1$O $(OBJDIR)$Pecdsa_i15_sign_raw$O $(OBJDIR)$Pecdsa_i15_vrfy_asn1$O $(OBJDIR)$Pecdsa_i15_vrfy_raw$O $(OBJDIR)$Pecdsa_i31_bits$O $(OBJDIR)$Pecdsa_i31_sign_asn1$O $(OBJDIR)$Pecdsa_i31_sign_raw$O $(OBJDIR)$Pecdsa_i31_vrfy_asn1$O $(OBJDIR)$Pecdsa_i31_vrfy_raw$O $(OBJDIR)$Pecdsa_rta$O $(OBJDIR)$Pdig_oid$O $(OBJDIR)$Pdig_size$O $(OBJDIR)$Pghash_ctmul$O $(OBJDIR)$Pghash_ctmul32$O $(OBJDIR)$Pghash_ctmul64$O $(OBJDIR)$Pghash_pclmul$O $(OBJDIR)$Pghash_pwr8$O $(OBJDIR)$Pmd5$O $(OBJDIR)$Pmd5sha1$O $(OBJDIR)$Pmultihash$O $(OBJDIR)$Psha1$O $(OBJDIR)$Psha2big$O $(OBJDIR)$Psha2small$O $(OBJDIR)$Pi15_add$O $(OBJDIR)$Pi15_bitlen$O $(OBJDIR)$Pi15_decmod$O $(OBJDIR)$Pi15_decode$O $(OBJDIR)$Pi15_decred$O $(OBJDIR)$Pi15_encode$O $(OBJDIR)$Pi15_fmont$O $(OBJDIR)$Pi15_iszero$O $(OBJDIR)$Pi15_modpow$O $(OBJDIR)$Pi15_modpow2$O $(OBJDIR)$Pi15_montmul$O $(OBJDIR)$Pi15_mulacc$O $(OBJDIR)$Pi15_muladd$O $(OBJDIR)$Pi15_ninv15$O $(OBJDIR)$Pi15_reduce$O $(OBJDIR)$Pi15_rshift$O $(OBJDIR)$Pi15_sub$O $(OBJDIR)$Pi15_tmont$O $(OBJDIR)$Pi31_add$O $(OBJDIR)$Pi31_bitlen$O $(OBJDIR)$Pi31_decmod$O $(OBJDIR)$Pi31_decode$O $(OBJDIR)$Pi31_decred$O $(OBJDIR)$Pi31_encode$O $(OBJDIR)$Pi31_fmont$O $(OBJDIR)$Pi31_iszero$O $(OBJDIR)$Pi31_modpow$O $(OBJDIR)$Pi31_modpow2$O $(OBJDIR)$Pi31_montmul$O $(OBJDIR)$Pi31_mulacc$O $(OBJDIR)$Pi31_muladd$O $(OBJDIR)$Pi31_ninv31$O $(OBJDIR)$Pi31_reduce$O $(OBJDIR)$Pi31_rshift$O $(OBJDIR)$Pi31_sub$O $(OBJDIR)$Pi31_tmont$O $(OBJDIR)$Pi32_add$O $(OBJDIR)$Pi32_bitlen$O $(OBJDIR)$Pi32_decmod$O $(OBJDIR)$Pi32_decode$O $(OBJDIR)$Pi32_decred$O $(OBJDIR)$Pi32_div32$O $(OBJDIR)$Pi32_encode$O $(OBJDIR)$Pi32_fmont$O $(OBJDIR)$Pi32_iszero$O $(OBJDIR)$Pi32_modpow$O $(OBJDIR)$Pi32_montmul$O $(OBJDIR)$Pi32_mulacc$O $(OBJDIR)$Pi32_muladd$O $(OBJDIR)$Pi32_ninv32$O $(OBJDIR)$Pi32_reduce$O $(OBJDIR)$Pi32_sub$O $(OBJDIR)$Pi32_tmont$O $(OBJDIR)$Pi62_modpow2$O $(OBJDIR)$Phmac$O $(OBJDIR)$Phmac_ct$O $(OBJDIR)$Phmac_drbg$O $(OBJDIR)$Prsa_default_pkcs1_sign$O $(OBJDIR)$Prsa_default_pkcs1_vrfy$O $(OBJDIR)$Prsa_default_priv$O $(OBJDIR)$Prsa_default_pub$O $(OBJDIR)$Prsa_i15_pkcs1_sign$O $(OBJDIR)$Prsa_i15_pkcs1_vrfy$O $(OBJDIR)$Prsa_i15_priv$O $(OBJDIR)$Prsa_i15_pub$O $(OBJDIR)$Prsa_i31_pkcs1_sign$O $(OBJDIR)$Prsa_i31_pkcs1_vrfy$O $(OBJDIR)$Prsa_i31_priv$O $(OBJDIR)$Prsa_i31_pub$O $(OBJDIR)$Prsa_i32_pkcs1_sign$O $(OBJDIR)$Prsa_i32_pkcs1_vrfy$O $(OBJDIR)$Prsa_i32_priv$O $(OBJDIR)$Prsa_i32_pub$O $(OBJDIR)$Prsa_i62_pkcs1_sign$O $(OBJDIR)$Prsa_i62_pkcs1_vrfy$O $(OBJDIR)$Prsa_i62_priv$O $(OBJDIR)$Prsa_i62_pub$O $(OBJDIR)$Prsa_pkcs1_sig_pad$O $(OBJDIR)$Prsa_pkcs1_sig_unpad$O $(OBJDIR)$Prsa_ssl_decrypt$O $(OBJDIR)$Pprf$O $(OBJDIR)$Pprf_md5sha1$O $(OBJDIR)$Pprf_sha256$O $(OBJDIR)$Pprf_sha384$O $(OBJDIR)$Pssl_ccert_single_ec$O $(OBJDIR)$Pssl_ccert_single_rsa$O $(OBJDIR)$Pssl_client$O $(OBJDIR)$Pssl_client_default_rsapub$O $(OBJDIR)$Pssl_client_full$O $(OBJDIR)$Pssl_engine$O $(OBJDIR)$Pssl_engine_default_aescbc$O $(OBJDIR)$Pssl_engine_default_aesgcm$O $(OBJDIR)$Pssl_engine_default_chapol$O $(OBJDIR)$Pssl_engine_default_descbc$O $(OBJDIR)$Pssl_engine_default_ec$O $(OBJDIR)$Pssl_engine_default_ecdsa$O $(OBJDIR)$Pssl_engine_default_rsavrfy$O $(OBJDIR)$Pssl_hashes$O $(OBJDIR)$Pssl_hs_client$O $(OBJDIR)$Pssl_hs_server$O $(OBJDIR)$Pssl_io$O $(OBJDIR)$Pssl_keyexport$O $(OBJDIR)$Pssl_lru$O $(OBJDIR)$Pssl_rec_cbc$O $(OBJDIR)$Pssl_rec_chapol$O $(OBJDIR)$Pssl_rec_gcm$O $(OBJDIR)$Pssl_scert_single_ec$O $(OBJDIR)$Pssl_scert_single_rsa$O $(OBJDIR)$Pssl_server$O $(OBJDIR)$Pssl_server_full_ec$O $(OBJDIR)$Pssl_server_full_rsa$O $(OBJDIR)$Pssl_server_mine2c$O $(OBJDIR)$Pssl_server_mine2g$O $(OBJDIR)$Pssl_server_minf2c$O $(OBJDIR)$Pssl_server_minf2g$O $(OBJDIR)$Pssl_server_minr2g$O $(OBJDIR)$Pssl_server_minu2g$O $(OBJDIR)$Pssl_server_minv2g$O $(OBJDIR)$Paes_big_cbcdec$O $(OBJDIR)$Paes_big_cbcenc$O $(OBJDIR)$Paes_big_ctr$O $(OBJDIR)$Paes_big_dec$O $(OBJDIR)$Paes_big_enc$O $(OBJDIR)$Paes_common$O $(OBJDIR)$Paes_ct$O $(OBJDIR)$Paes_ct64$O $(OBJDIR)$Paes_ct64_cbcdec$O $(OBJDIR)$Paes_ct64_cbcenc$O $(OBJDIR)$Paes_ct64_ctr$O $(OBJDIR)$Paes_ct64_dec$O $(OBJDIR)$Paes_ct64_enc$O $(OBJDIR)$Paes_ct_cbcdec$O $(OBJDIR)$Paes_ct_cbcenc$O $(OBJDIR)$Paes_ct_ctr$O $(OBJDIR)$Paes_ct_dec$O $(OBJDIR)$Paes_ct_enc$O $(OBJDIR)$Paes_pwr8$O $(OBJDIR)$Paes_pwr8_cbcdec$O $(OBJDIR)$Paes_pwr8_cbcenc$O $(OBJDIR)$Paes_pwr8_ctr$O $(OBJDIR)$Paes_small_cbcdec$O $(OBJDIR)$Paes_small_cbcenc$O $(OBJDIR)$Paes_small_ctr$O $(OBJDIR)$Paes_small_dec$O $(OBJDIR)$Paes_small_enc$O $(OBJDIR)$Paes_x86ni$O $(OBJDIR)$Paes_x86ni_cbcdec$O $(OBJDIR)$Paes_x86ni_cbcenc$O $(OBJDIR)$Paes_x86ni_ctr$O $(OBJDIR)$Pchacha20_ct$O $(OBJDIR)$Pchacha20_sse2$O $(OBJDIR)$Pdes_ct$O $(OBJDIR)$Pdes_ct_cbcdec$O $(OBJDIR)$Pdes_ct_cbcenc$O $(OBJDIR)$Pdes_support$O $(OBJDIR)$Pdes_tab$O $(OBJDIR)$Pdes_tab_cbcdec$O $(OBJDIR)$Pdes_tab_cbcenc$O $(OBJDIR)$Ppoly1305_ctmul$O $(OBJDIR)$Ppoly1305_ctmul32$O $(OBJDIR)$Ppoly1305_ctmulq$O $(OBJDIR)$Ppoly1305_i15$O $(OBJDIR)$Pskey_decoder$O $(OBJDIR)$Px509_decoder$O $(OBJDIR)$Px509_knownkey$O $(OBJDIR)$Px509_minimal$O $(OBJDIR)$Px509_minimal_full$O
-OBJBRSSL = $(OBJDIR)$Pbrssl$O $(OBJDIR)$Pcerts$O $(OBJDIR)$Pchain$O $(OBJDIR)$Pclient$O $(OBJDIR)$Perrors$O $(OBJDIR)$Pfiles$O $(OBJDIR)$Pkeys$O $(OBJDIR)$Pnames$O $(OBJDIR)$Pserver$O $(OBJDIR)$Pskey$O $(OBJDIR)$Psslio$O $(OBJDIR)$Pta$O $(OBJDIR)$Pvector$O $(OBJDIR)$Pverify$O $(OBJDIR)$Pxmem$O
+OBJBRSSL = $(OBJDIR)$Pbrssl$O $(OBJDIR)$Pcerts$O $(OBJDIR)$Pchain$O $(OBJDIR)$Pclient$O $(OBJDIR)$Perrors$O $(OBJDIR)$Pfiles$O $(OBJDIR)$Pkeys$O $(OBJDIR)$Pnames$O $(OBJDIR)$Pserver$O $(OBJDIR)$Pskey$O $(OBJDIR)$Psslio$O $(OBJDIR)$Pta$O $(OBJDIR)$Ptwrch$O $(OBJDIR)$Pvector$O $(OBJDIR)$Pverify$O $(OBJDIR)$Pxmem$O
 OBJTESTCRYPTO = $(OBJDIR)$Ptest_crypto$O
 OBJTESTSPEED = $(OBJDIR)$Ptest_speed$O
 OBJTESTX509 = $(OBJDIR)$Ptest_x509$O
@@ -775,6 +775,9 @@ $(OBJDIR)$Psslio$O: tools$Psslio.c $(HEADERSTOOLS)
 $(OBJDIR)$Pta$O: tools$Pta.c $(HEADERSTOOLS)
 	$(CC) $(CFLAGS) $(INCFLAGS) $(CCOUT)$(OBJDIR)$Pta$O tools$Pta.c
 
+$(OBJDIR)$Ptwrch$O: tools$Ptwrch.c $(HEADERSTOOLS)
+	$(CC) $(CFLAGS) $(INCFLAGS) $(CCOUT)$(OBJDIR)$Ptwrch$O tools$Ptwrch.c
+
 $(OBJDIR)$Pvector$O: tools$Pvector.c $(HEADERSTOOLS)
 	$(CC) $(CFLAGS) $(INCFLAGS) $(CCOUT)$(OBJDIR)$Pvector$O tools$Pvector.c
 
diff --git a/mk/mkrules.sh b/mk/mkrules.sh
index eab5287..26f8546 100755
--- a/mk/mkrules.sh
+++ b/mk/mkrules.sh
@@ -290,6 +290,7 @@ toolssrc=" \
 	tools/skey.c \
 	tools/sslio.c \
 	tools/ta.c \
+	tools/twrch.c \
 	tools/vector.c \
 	tools/verify.c \
 	tools/xmem.c"
diff --git a/tools/brssl.c b/tools/brssl.c
index aba79e1..76f7539 100644
--- a/tools/brssl.c
+++ b/tools/brssl.c
@@ -50,6 +50,7 @@ usage(void)
 	fprintf(stderr, "   skey         decode private key\n");
 	fprintf(stderr, "   ta           decode trust anchors\n");
 	fprintf(stderr, "   chain        make C code for certificate chains\n");
+	fprintf(stderr, "   twrch        run the Twrch protocol\n");
 }
 
 int
@@ -98,6 +99,15 @@ main(int argc, char *argv[])
 		if (do_chain(argc - 2, argv + 2) < 0) {
 			return EXIT_FAILURE;
 		}
+	} else if (eqstr(cmd, "twrch")) {
+		int ret;
+
+		ret = do_twrch(argc - 2, argv + 2);
+		if (ret < 0) {
+			return EXIT_FAILURE;
+		} else {
+			return ret;
+		}
 	} else {
 		fprintf(stderr, "unknown command: '%s'\n", cmd);
 		usage();
diff --git a/tools/brssl.h b/tools/brssl.h
index f2957e6..c47a026 100644
--- a/tools/brssl.h
+++ b/tools/brssl.h
@@ -485,7 +485,8 @@ const char *get_algo_name(const void *algo, int long_name);
 
 /*
  * Run a SSL engine, with a socket connected to the peer, and using
- * stdin/stdout to exchange application data.
+ * stdin/stdout to exchange application data. The socket must be a
+ * non-blocking descriptor.
  *
  * To help with Win32 compatibility, the socket descriptor is provided
  * as an "unsigned long" value.
@@ -538,4 +539,11 @@ int do_ta(int argc, char *argv[]);
  */
 int do_chain(int argc, char *argv[]);
 
+/*
+ * Do the "twrch" command. Returned value is 0 on success, -1 on failure
+ * (processing or arguments), or a non-zero exit code. Command-line
+ * arguments start _after_ the command name.
+ */
+int do_twrch(int argc, char *argv[]);
+
 #endif
diff --git a/tools/client.c b/tools/client.c
index fad18e0..acd8512 100644
--- a/tools/client.c
+++ b/tools/client.c
@@ -764,7 +764,7 @@ do_client(int argc, char *argv[])
 			}
 			arg = argv[i];
 			if (minhello_len != (size_t)-1) {
-				fprintf(stderr, "ERROR: duplicate minium"
+				fprintf(stderr, "ERROR: duplicate minimum"
 					" ClientHello length\n");
 				usage_client();
 				goto client_exit_error;
diff --git a/tools/server.c b/tools/server.c
index cb04711..cac99c4 100644
--- a/tools/server.c
+++ b/tools/server.c
@@ -166,7 +166,7 @@ host_bind(const char *host, const char *port, int verbose)
 }
 
 static SOCKET
-accept_client(SOCKET server_fd, int verbose)
+accept_client(SOCKET server_fd, int verbose, int nonblock)
 {
 	int fd;
 	SOCKADDR_STORAGE sa;
@@ -209,16 +209,16 @@ accept_client(SOCKET server_fd, int verbose)
 	 * We make the socket non-blocking, since we are going to use
 	 * poll() or select() to organise I/O.
 	 */
+	if (nonblock) {
 #ifdef _WIN32
-	{
 		u_long arg;
 
 		arg = 1;
 		ioctlsocket(fd, FIONBIO, &arg);
-	}
 #else
-	fcntl(fd, F_SETFL, O_NONBLOCK);
+		fcntl(fd, F_SETFL, O_NONBLOCK);
 #endif
+	}
 	return fd;
 }
 
@@ -1177,15 +1177,16 @@ do_server(int argc, char *argv[])
 	 */
 	for (;;) {
 		int x;
+		unsigned run_flags;
 
-		fd = accept_client(server_fd, verbose);
+		fd = accept_client(server_fd, verbose, 1);
 		if (fd == INVALID_SOCKET) {
 			goto server_exit_error;
 		}
 		br_ssl_server_reset(&cc);
-		x = run_ssl_engine(&cc.eng, fd,
-			(verbose ? RUN_ENGINE_VERBOSE : 0)
-			| (trace ? RUN_ENGINE_TRACE : 0));
+		run_flags = (verbose ? RUN_ENGINE_VERBOSE : 0)
+			| (trace ? RUN_ENGINE_TRACE : 0);
+		x = run_ssl_engine(&cc.eng, fd, run_flags);
 #ifdef _WIN32
 		closesocket(fd);
 #else
diff --git a/tools/twrch.c b/tools/twrch.c
new file mode 100644
index 0000000..3342667
--- /dev/null
+++ b/tools/twrch.c
@@ -0,0 +1,1066 @@
+/*
+ * Copyright (c) 2017 Thomas Pornin <pornin@bolet.org>
+ *
+ * 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 <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <errno.h>
+
+#ifdef _WIN32
+#include <windows.h>
+#else
+#include <signal.h>
+#include <sys/types.h>
+#include <unistd.h>
+#endif
+
+#include "brssl.h"
+
+static int verbose = 0;
+
+static void
+usage_twrch(void)
+{
+	fprintf(stderr,
+"usage: brssl twrch [ options ]\n");
+	fprintf(stderr,
+"options:\n");
+	fprintf(stderr,
+"   -trace          dump all packets on stderr\n");
+	fprintf(stderr,
+"   -v              verbose error messages on stderr\n");
+	fprintf(stderr,
+"   -server         act as an SSL server\n");
+	fprintf(stderr,
+"   -client         act as an SSL client\n");
+	fprintf(stderr,
+"   -sni name       use specified name for SNI\n");
+	fprintf(stderr,
+"   -mono           use monodirectional buffering\n");
+	fprintf(stderr,
+"   -buf length     set the I/O buffer length (in bytes)\n");
+	fprintf(stderr,
+"   -cache length   set the session cache storage length (in bytes)\n");
+	fprintf(stderr,
+"   -cert fname     read certificate chain from file 'fname'\n");
+	fprintf(stderr,
+"   -key fname      read private key from file 'fname'\n");
+	fprintf(stderr,
+"   -CA file        add trust anchors from 'file' (for peer auth)\n");
+	fprintf(stderr,
+"   -anon_ok        request but do not require a client certificate\n");
+	fprintf(stderr,
+"   -nostaticecdh   prohibit full-static ECDH (client only)\n");
+	fprintf(stderr,
+"   -list           list supported names (protocols, algorithms...)\n");
+	fprintf(stderr,
+"   -vmin name      set minimum supported version (default: TLS-1.0)\n");
+	fprintf(stderr,
+"   -vmax name      set maximum supported version (default: TLS-1.2)\n");
+	fprintf(stderr,
+"   -cs names       set list of supported cipher suites (comma-separated)\n");
+	fprintf(stderr,
+"   -hf names       add support for some hash functions (comma-separated)\n");
+	fprintf(stderr,
+"   -minhello len   set minimum ClientHello length (in bytes)\n");
+	fprintf(stderr,
+"   -serverpref     enforce server's preferences for cipher suites\n");
+	fprintf(stderr,
+"   -noreneg        prohibit renegotiations\n");
+	fprintf(stderr,
+"   -alpn name      add protocol name to list of protocols (ALPN extension)\n");
+	fprintf(stderr,
+"   -strictalpn     fail on ALPN mismatch\n");
+}
+
+static void
+free_alpn(void *alpn)
+{
+	xfree(*(char **)alpn);
+}
+
+static void
+dump_blob(const char *name, const void *data, size_t len)
+{
+	const unsigned char *buf;
+	size_t u;
+
+	buf = data;
+	fprintf(stderr, "%s (len = %lu)", name, (unsigned long)len);
+	for (u = 0; u < len; u ++) {
+		if ((u & 15) == 0) {
+			fprintf(stderr, "\n%08lX  ", (unsigned long)u);
+		} else if ((u & 7) == 0) {
+			fprintf(stderr, " ");
+		}
+		fprintf(stderr, " %02x", buf[u]);
+	}
+	fprintf(stderr, "\n");
+}
+
+/*
+ * Callback for reading bytes from standard input.
+ */
+static int
+stdin_read(void *ctx, unsigned char *buf, size_t len)
+{
+	for (;;) {
+#ifdef _WIN32
+		DWORD rlen;
+#else
+		ssize_t rlen;
+#endif
+		int eof;
+
+#ifdef _WIN32
+		eof = !ReadFile(GetStdHandle(STD_INPUT_HANDLE),
+			buf, len, &rlen, NULL) || rlen == 0;
+#else
+		rlen = read(0, buf, len);
+		if (rlen <= 0) {
+			if (rlen < 0 && errno == EINTR) {
+				continue;
+			}
+			eof = 1;
+		} else {
+			eof = 0;
+		}
+#endif
+		if (eof) {
+			if (*(int *)ctx) {
+				if (verbose) {
+					fprintf(stderr, "recv: EOF\n");
+				}
+			}
+			return -1;
+		}
+		if (*(int *)ctx) {
+			dump_blob("recv", buf, (size_t)rlen);
+		}
+		return (int)rlen;
+	}
+}
+
+/*
+ * Callback for writing bytes on standard output.
+ */
+static int
+stdout_write(void *ctx, const unsigned char *buf, size_t len)
+{
+	for (;;) {
+#ifdef _WIN32
+		DWORD wlen;
+#else
+		ssize_t wlen;
+#endif
+		int eof;
+
+#ifdef _WIN32
+		eof = !WriteFile(GetStdHandle(STD_OUTPUT_HANDLE),
+			buf, len, &wlen, NULL);
+#else
+		wlen = write(1, buf, len);
+		if (wlen <= 0) {
+			if (wlen < 0 && errno == EINTR) {
+				continue;
+			}
+			eof = 1;
+		} else {
+			eof = 0;
+		}
+#endif
+		if (eof) {
+			if (*(int *)ctx) {
+				if (verbose) {
+					fprintf(stderr, "send: EOF\n");
+				}
+			}
+			return -1;
+		}
+		if (*(int *)ctx) {
+			dump_blob("send", buf, (size_t)wlen);
+		}
+		return (int)wlen;
+	}
+}
+
+static void
+print_error(int err)
+{
+	const char *name, *comment;
+
+	name = find_error_name(err, &comment);
+	if (name != NULL) {
+		fprintf(stderr, "ERR %d: %s\n   %s\n", err, name, comment);
+		return;
+	}
+	if (err >= BR_ERR_RECV_FATAL_ALERT
+		&& err < BR_ERR_RECV_FATAL_ALERT + 256)
+	{
+		fprintf(stderr, "ERR %d: received fatal alert %d\n",
+			err, err - BR_ERR_RECV_FATAL_ALERT);
+		return;
+	}
+	if (err >= BR_ERR_SEND_FATAL_ALERT
+		&& err < BR_ERR_SEND_FATAL_ALERT + 256)
+	{
+		fprintf(stderr, "ERR %d: sent fatal alert %d\n",
+			err, err - BR_ERR_SEND_FATAL_ALERT);
+		return;
+	}
+	fprintf(stderr, "ERR %d: UNKNOWN\n", err);
+}
+
+/* see brssl.h */
+int
+do_twrch(int argc, char *argv[])
+{
+	int retcode;
+	int trace;
+	int is_client;
+	int is_server;
+	const char *sni;
+	int i, bidi;
+	unsigned vmin, vmax;
+	cipher_suite *suites;
+	size_t num_suites;
+	uint16_t *suite_ids;
+	unsigned hfuns;
+	br_x509_certificate *chain;
+	size_t chain_len;
+	int cert_signer_algo;
+	private_key *sk;
+	int nostaticecdh;
+	anchor_list anchors = VEC_INIT;
+	VECTOR(char *) alpn_names = VEC_INIT;
+	br_x509_minimal_context xc;
+	x509_noanchor_context xwc;
+	const br_hash_class *dnhash;
+	size_t u;
+	union {
+		br_ssl_engine_context eng;
+		br_ssl_server_context srv;
+		br_ssl_client_context cnt;
+	} cc;
+	br_ssl_session_cache_lru lru;
+	unsigned char *iobuf, *cache;
+	size_t iobuf_len, cache_len, minhello_len;
+	br_sslio_context ioc;
+	uint32_t flags;
+	int reconnect;
+
+	retcode = 0;
+	trace = 0;
+	is_client = 0;
+	is_server = 0;
+	sni = NULL;
+	bidi = 1;
+	vmin = 0;
+	vmax = 0;
+	suites = NULL;
+	num_suites = 0;
+	suite_ids = NULL;
+	hfuns = 0;
+	chain = NULL;
+	chain_len = 0;
+	cert_signer_algo = 0;
+	sk = NULL;
+	nostaticecdh = 0;
+	iobuf = NULL;
+	iobuf_len = 0;
+	cache = NULL;
+	cache_len = (size_t)-1;
+	minhello_len = (size_t)-1;
+	flags = 0;
+	reconnect = 0;
+	for (i = 0; i < argc; i ++) {
+		const char *arg;
+
+		arg = argv[i];
+		if (arg[0] != '-') {
+			usage_twrch();
+			goto twrch_exit_error;
+		}
+		if (eqstr(arg, "-trace")) {
+			trace = 1;
+		} else if (eqstr(arg, "-v")) {
+			verbose = 1;
+		} else if (eqstr(arg, "-server")) {
+			is_server = 1;
+		} else if (eqstr(arg, "-client")) {
+			is_client = 1;
+		} else if (eqstr(arg, "-sni")) {
+			if (++ i >= argc) {
+				fprintf(stderr,
+					"ERROR: no argument for '-sni'\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			arg = argv[i];
+			if (sni != NULL) {
+				fprintf(stderr, "ERROR: duplicate SNI\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			sni = arg;
+		} else if (eqstr(arg, "-mono")) {
+			bidi = 0;
+		} else if (eqstr(arg, "-buf")) {
+			if (++ i >= argc) {
+				fprintf(stderr,
+					"ERROR: no argument for '-buf'\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			arg = argv[i];
+			if (iobuf_len != 0) {
+				fprintf(stderr,
+					"ERROR: duplicate I/O buffer length\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			iobuf_len = parse_size(arg);
+			if (iobuf_len == (size_t)-1) {
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+		} else if (eqstr(arg, "-cache")) {
+			if (++ i >= argc) {
+				fprintf(stderr,
+					"ERROR: no argument for '-cache'\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			arg = argv[i];
+			if (cache_len != (size_t)-1) {
+				fprintf(stderr, "ERROR: duplicate session"
+					" cache length\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			cache_len = parse_size(arg);
+			if (cache_len == (size_t)-1) {
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+		} else if (eqstr(arg, "-cert")) {
+			if (++ i >= argc) {
+				fprintf(stderr,
+					"ERROR: no argument for '-cert'\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			if (chain != NULL) {
+				fprintf(stderr,
+					"ERROR: duplicate certificate chain\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			arg = argv[i];
+			chain = read_certificates(arg, &chain_len);
+			if (chain == NULL || chain_len == 0) {
+				goto twrch_exit_error;
+			}
+		} else if (eqstr(arg, "-key")) {
+			if (++ i >= argc) {
+				fprintf(stderr,
+					"ERROR: no argument for '-key'\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			if (sk != NULL) {
+				fprintf(stderr,
+					"ERROR: duplicate private key\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			arg = argv[i];
+			sk = read_private_key(arg);
+			if (sk == NULL) {
+				goto twrch_exit_error;
+			}
+		} else if (eqstr(arg, "-CA")) {
+			if (++ i >= argc) {
+				fprintf(stderr,
+					"ERROR: no argument for '-CA'\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			arg = argv[i];
+			if (read_trust_anchors(&anchors, arg) == 0) {
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+		} else if (eqstr(arg, "-anon_ok")) {
+			flags |= BR_OPT_TOLERATE_NO_CLIENT_AUTH;
+		} else if (eqstr(arg, "-nostaticecdh")) {
+			nostaticecdh = 1;
+		} else if (eqstr(arg, "-list")) {
+			list_names();
+			goto twrch_exit;
+		} else if (eqstr(arg, "-vmin")) {
+			if (++ i >= argc) {
+				fprintf(stderr,
+					"ERROR: no argument for '-vmin'\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			arg = argv[i];
+			if (vmin != 0) {
+				fprintf(stderr,
+					"ERROR: duplicate minimum version\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			vmin = parse_version(arg, strlen(arg));
+			if (vmin == 0) {
+				fprintf(stderr,
+					"ERROR: unrecognised version '%s'\n",
+					arg);
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+		} else if (eqstr(arg, "-vmax")) {
+			if (++ i >= argc) {
+				fprintf(stderr,
+					"ERROR: no argument for '-vmax'\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			arg = argv[i];
+			if (vmax != 0) {
+				fprintf(stderr,
+					"ERROR: duplicate maximum version\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			vmax = parse_version(arg, strlen(arg));
+			if (vmax == 0) {
+				fprintf(stderr,
+					"ERROR: unrecognised version '%s'\n",
+					arg);
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+		} else if (eqstr(arg, "-cs")) {
+			if (++ i >= argc) {
+				fprintf(stderr,
+					"ERROR: no argument for '-cs'\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			arg = argv[i];
+			if (suites != NULL) {
+				fprintf(stderr, "ERROR: duplicate list"
+					" of cipher suites\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			suites = parse_suites(arg, &num_suites);
+			if (suites == NULL) {
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+		} else if (eqstr(arg, "-hf")) {
+			unsigned x;
+
+			if (++ i >= argc) {
+				fprintf(stderr,
+					"ERROR: no argument for '-hf'\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			arg = argv[i];
+			x = parse_hash_functions(arg);
+			if (x == 0) {
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			hfuns |= x;
+		} else if (eqstr(arg, "-minhello")) {
+			if (++ i >= argc) {
+				fprintf(stderr,
+					"ERROR: no argument for '-minhello'\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			arg = argv[i];
+			if (minhello_len != (size_t)-1) {
+				fprintf(stderr, "ERROR: duplicate minimum"
+					" ClientHello length\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			minhello_len = parse_size(arg);
+			/*
+			 * Minimum ClientHello length must fit on 16 bits.
+			 */
+			if (minhello_len == (size_t)-1
+				|| (((minhello_len >> 12) >> 4) != 0))
+			{
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+		} else if (eqstr(arg, "-serverpref")) {
+			flags |= BR_OPT_ENFORCE_SERVER_PREFERENCES;
+		} else if (eqstr(arg, "-noreneg")) {
+			flags |= BR_OPT_NO_RENEGOTIATION;
+		} else if (eqstr(arg, "-alpn")) {
+			if (++ i >= argc) {
+				fprintf(stderr,
+					"ERROR: no argument for '-alpn'\n");
+				usage_twrch();
+				goto twrch_exit_error;
+			}
+			VEC_ADD(alpn_names, xstrdup(argv[i]));
+		} else if (eqstr(arg, "-strictalpn")) {
+			flags |= BR_OPT_FAIL_ON_ALPN_MISMATCH;
+		} else {
+			fprintf(stderr, "ERROR: unknown option: '%s'\n", arg);
+			usage_twrch();
+			goto twrch_exit_error;
+		}
+	}
+
+	/*
+	 * Verify consistency of options.
+	 */
+	if (!is_client && !is_server) {
+		fprintf(stderr, "ERROR:"
+			" one of -server and -client must be specified\n");
+		usage_twrch();
+		goto twrch_exit_error;
+	}
+	if (is_client && is_server) {
+		fprintf(stderr, "ERROR:"
+			" -server and -client may not be both specified\n");
+		usage_twrch();
+		goto twrch_exit_error;
+	}
+
+	if (vmin == 0) {
+		vmin = BR_TLS10;
+	}
+	if (vmax == 0) {
+		vmax = BR_TLS12;
+	}
+	if (vmax < vmin) {
+		fprintf(stderr, "ERROR: impossible minimum/maximum protocol"
+			" version combination\n");
+		usage_twrch();
+		goto twrch_exit_error;
+	}
+	if (is_server) {
+		if (chain == NULL) {
+			fprintf(stderr, "ERROR: no certificate specified"
+				" for server (-cert)\n");
+			usage_twrch();
+			goto twrch_exit_error;
+		}
+		if (sk == NULL) {
+			fprintf(stderr, "ERROR: no private key specified"
+				" for server (-key)\n");
+			usage_twrch();
+			goto twrch_exit_error;
+		}
+	} else {
+		if (chain == NULL && sk != NULL) {
+			fprintf(stderr, "ERROR: private key (-key)"
+				" but no certificate (-cert)");
+			usage_twrch();
+			goto twrch_exit_error;
+		}
+		if (chain != NULL && sk == NULL) {
+			fprintf(stderr, "ERROR: certificate (-cert)"
+				" but no private key (-key)");
+			usage_twrch();
+			goto twrch_exit_error;
+		}
+	}
+	if (suites == NULL) {
+		num_suites = 0;
+
+		for (u = 0; cipher_suites[u].name; u ++) {
+			if ((cipher_suites[u].req & REQ_TLS12) == 0
+				|| vmax >= BR_TLS12)
+			{
+				num_suites ++;
+			}
+		}
+		suites = xmalloc(num_suites * sizeof *suites);
+		num_suites = 0;
+		for (u = 0; cipher_suites[u].name; u ++) {
+			if ((cipher_suites[u].req & REQ_TLS12) == 0
+				|| vmax >= BR_TLS12)
+			{
+				suites[num_suites ++] = cipher_suites[u];
+			}
+		}
+	}
+	if (hfuns == 0) {
+		hfuns = (unsigned)-1;
+	}
+	if (sk != NULL) {
+		switch (sk->key_type) {
+			int curve;
+			uint32_t supp;
+
+		case BR_KEYTYPE_RSA:
+			break;
+		case BR_KEYTYPE_EC:
+			curve = sk->key.ec.curve;
+			supp = br_ec_get_default()->supported_curves;
+			if (curve > 31 || !((supp >> curve) & 1)) {
+				fprintf(stderr, "ERROR: private key curve (%d)"
+					" is not supported\n", curve);
+				goto twrch_exit_error;
+			}
+			break;
+		default:
+			fprintf(stderr, "ERROR: unsupported"
+				" private key type (%d)\n", sk->key_type);
+			goto twrch_exit_error;
+		}
+	}
+	if (chain != NULL) {
+		cert_signer_algo = get_cert_signer_algo(chain);
+		if (cert_signer_algo == 0) {
+			goto twrch_exit_error;
+		}
+	}
+	if (iobuf_len == 0) {
+		if (bidi) {
+			iobuf_len = BR_SSL_BUFSIZE_BIDI;
+		} else {
+			iobuf_len = BR_SSL_BUFSIZE_MONO;
+		}
+	}
+	iobuf = xmalloc(iobuf_len);
+	if (is_server) {
+		if (cache_len == (size_t)-1) {
+			cache_len = 5000;
+		}
+		cache = xmalloc(cache_len);
+	}
+
+	/*
+	 * Initialise the relevant context.
+	 */
+	if (is_client) {
+		br_ssl_client_zero(&cc.cnt);
+	} else {
+		br_ssl_server_zero(&cc.srv);
+	}
+
+	/*
+	 * Compute implementation requirements and inject implementations.
+	 */
+	suite_ids = xmalloc(num_suites * sizeof *suite_ids);
+	br_ssl_engine_set_versions(&cc.eng, vmin, vmax);
+	br_ssl_engine_set_all_flags(&cc.eng, flags);
+	if (vmin <= BR_TLS11) {
+		if (!(hfuns & (1 << br_md5_ID))) {
+			fprintf(stderr, "ERROR: TLS 1.0 and 1.1 need MD5\n");
+			goto twrch_exit_error;
+		}
+		if (!(hfuns & (1 << br_sha1_ID))) {
+			fprintf(stderr, "ERROR: TLS 1.0 and 1.1 need SHA-1\n");
+			goto twrch_exit_error;
+		}
+	}
+	for (u = 0; u < num_suites; u ++) {
+		unsigned req;
+
+		req = suites[u].req;
+		suite_ids[u] = suites[u].suite;
+		if ((req & REQ_TLS12) != 0 && vmax < BR_TLS12) {
+			fprintf(stderr,
+				"ERROR: cipher suite %s requires TLS 1.2\n",
+				suites[u].name);
+			goto twrch_exit_error;
+		}
+		if ((req & REQ_SHA1) != 0 && !(hfuns & (1 << br_sha1_ID))) {
+			fprintf(stderr,
+				"ERROR: cipher suite %s requires SHA-1\n",
+				suites[u].name);
+			goto twrch_exit_error;
+		}
+		if ((req & REQ_SHA256) != 0 && !(hfuns & (1 << br_sha256_ID))) {
+			fprintf(stderr,
+				"ERROR: cipher suite %s requires SHA-256\n",
+				suites[u].name);
+			goto twrch_exit_error;
+		}
+		if ((req & REQ_SHA384) != 0 && !(hfuns & (1 << br_sha384_ID))) {
+			fprintf(stderr,
+				"ERROR: cipher suite %s requires SHA-384\n",
+				suites[u].name);
+			goto twrch_exit_error;
+		}
+		/* TODO: algorithm implementation selection */
+		if ((req & REQ_AESCBC) != 0) {
+			br_ssl_engine_set_default_aes_cbc(&cc.eng);
+		}
+		if ((req & REQ_AESGCM) != 0) {
+			br_ssl_engine_set_default_aes_gcm(&cc.eng);
+		}
+		if ((req & REQ_CHAPOL) != 0) {
+			br_ssl_engine_set_default_chapol(&cc.eng);
+		}
+		if ((req & REQ_3DESCBC) != 0) {
+			br_ssl_engine_set_default_des_cbc(&cc.eng);
+		}
+		if (is_client && (req & REQ_RSAKEYX) != 0) {
+			br_ssl_client_set_default_rsapub(&cc.cnt);
+		}
+		if (is_client && (req & REQ_ECDHE_RSA) != 0) {
+			br_ssl_engine_set_default_rsavrfy(&cc.eng);
+		}
+		if (is_client && (req & REQ_ECDH) != 0) {
+			br_ssl_engine_set_default_ec(&cc.eng);
+		}
+		if ((req & (REQ_ECDHE_RSA | REQ_ECDHE_ECDSA)) != 0) {
+			br_ssl_engine_set_default_ec(&cc.eng);
+		}
+	}
+	br_ssl_engine_set_suites(&cc.eng, suite_ids, num_suites);
+
+	dnhash = NULL;
+	for (u = 0; hash_functions[u].name; u ++) {
+		const br_hash_class *hc;
+		int id;
+
+		hc = hash_functions[u].hclass;
+		id = (hc->desc >> BR_HASHDESC_ID_OFF) & BR_HASHDESC_ID_MASK;
+		if ((hfuns & ((unsigned)1 << id)) != 0) {
+			dnhash = hc;
+			br_ssl_engine_set_hash(&cc.eng, id, hc);
+		}
+	}
+	if (vmin <= BR_TLS11) {
+		br_ssl_engine_set_prf10(&cc.eng, &br_tls10_prf);
+	}
+	if (vmax >= BR_TLS12) {
+		if ((hfuns & ((unsigned)1 << br_sha256_ID)) != 0) {
+			br_ssl_engine_set_prf_sha256(&cc.eng,
+				&br_tls12_sha256_prf);
+		}
+		if ((hfuns & ((unsigned)1 << br_sha384_ID)) != 0) {
+			br_ssl_engine_set_prf_sha384(&cc.eng,
+				&br_tls12_sha384_prf);
+		}
+	}
+	if (VEC_LEN(alpn_names) != 0) {
+		br_ssl_engine_set_protocol_names(&cc.eng,
+			(const char **)&VEC_ELT(alpn_names, 0),
+			VEC_LEN(alpn_names));
+	}
+
+	/*
+	 * In server role, we use a session cache (size can be
+	 * specified; if size is zero, then no cache is set).
+	 */
+	if (is_server && cache != NULL) {
+		br_ssl_session_cache_lru_init(&lru, cache, cache_len);
+		br_ssl_server_set_cache(&cc.srv, &lru.vtable);
+	}
+
+	/*
+	 * For a server, set the policy handler.
+	 */
+	if (is_server) {
+		switch (sk->key_type) {
+		case BR_KEYTYPE_RSA:
+			br_ssl_server_set_single_rsa(&cc.srv,
+				chain, chain_len, &sk->key.rsa,
+				BR_KEYTYPE_KEYX | BR_KEYTYPE_SIGN,
+				br_rsa_private_get_default(),
+				br_rsa_pkcs1_sign_get_default());
+			break;
+		case BR_KEYTYPE_EC:
+			br_ssl_server_set_single_ec(&cc.srv,
+				chain, chain_len, &sk->key.ec,
+				BR_KEYTYPE_KEYX | BR_KEYTYPE_SIGN,
+				cert_signer_algo,
+				br_ec_get_default(),
+				br_ecdsa_sign_asn1_get_default());
+			break;
+		default:
+			fprintf(stderr, "ERROR: unsupported"
+				" private key type (%d)\n", sk->key_type);
+			goto twrch_exit_error;
+		}
+	}
+
+	/*
+	 * For a client, if a certificate was specified, use it.
+	 */
+	if (is_client && chain != NULL) {
+		switch (sk->key_type) {
+			unsigned usages;
+
+		case BR_KEYTYPE_RSA:
+			br_ssl_client_set_single_rsa(&cc.cnt,
+				chain, chain_len, &sk->key.rsa,
+				br_rsa_pkcs1_sign_get_default());
+			break;
+		case BR_KEYTYPE_EC:
+			if (nostaticecdh) {
+				cert_signer_algo = 0;
+				usages = BR_KEYTYPE_SIGN;
+			} else {
+				usages = BR_KEYTYPE_KEYX | BR_KEYTYPE_SIGN;
+			}
+			br_ssl_client_set_single_ec(&cc.cnt,
+				chain, chain_len, &sk->key.ec,
+				usages, cert_signer_algo,
+				br_ec_get_default(),
+				br_ecdsa_sign_asn1_get_default());
+			break;
+		default:
+			fprintf(stderr, "ERROR: unsupported"
+				" private key type (%d)\n", sk->key_type);
+			goto twrch_exit_error;
+		}
+	}
+
+	/*
+	 * On a client, or if trust anchors have been configured, then
+	 * set an X.509 validation engine. If there are no trust anchors
+	 * (client only), then a "no anchor" wrapper will be applied.
+	 */
+	if (is_client || VEC_LEN(anchors) != 0) {
+		br_x509_minimal_init(&xc, dnhash,
+			&VEC_ELT(anchors, 0), VEC_LEN(anchors));
+		for (u = 0; hash_functions[u].name; u ++) {
+			const br_hash_class *hc;
+			int id;
+
+			hc = hash_functions[u].hclass;
+			id = (hc->desc >> BR_HASHDESC_ID_OFF)
+				& BR_HASHDESC_ID_MASK;
+			if ((hfuns & ((unsigned)1 << id)) != 0) {
+				br_x509_minimal_set_hash(&xc, id, hc);
+			}
+		}
+		br_ssl_engine_set_default_rsavrfy(&cc.eng);
+		br_ssl_engine_set_default_ecdsa(&cc.eng);
+		br_x509_minimal_set_rsa(&xc, br_rsa_pkcs1_vrfy_get_default());
+		br_x509_minimal_set_ecdsa(&xc,
+			br_ec_get_default(), br_ecdsa_vrfy_asn1_get_default());
+		br_ssl_engine_set_x509(&cc.eng, &xc.vtable);
+
+		if (VEC_LEN(anchors) == 0) {
+			x509_noanchor_init(&xwc, &xc.vtable);
+			br_ssl_engine_set_x509(&cc.eng, &xwc.vtable);
+		} else {
+			br_ssl_engine_set_x509(&cc.eng, &xc.vtable);
+		}
+		if (is_server) {
+			br_ssl_server_set_trust_anchor_names_alt(&cc.srv,
+				&VEC_ELT(anchors, 0), VEC_LEN(anchors));
+		}
+	}
+
+	/*
+	 * Set I/O buffer.
+	 */
+	br_ssl_engine_set_buffer(&cc.eng, iobuf, iobuf_len, bidi);
+
+	/*
+	 * Start the engine.
+	 */
+	if (is_client) {
+		br_ssl_client_reset(&cc.cnt, sni, 0);
+	}
+	if (is_server) {
+		br_ssl_server_reset(&cc.srv);
+	}
+
+	/*
+	 * On Unix systems, we want to ignore SIGPIPE: if the peer
+	 * closes the connection abruptly, then we want to report it
+	 * as a "normal" error (exit code = 1).
+	 */
+#ifndef _WIN32
+	signal(SIGPIPE, SIG_IGN);
+#endif
+
+	/*
+	 * Initialize the callbacks for exchanging data over stdin and
+	 * stdout.
+	 */
+	br_sslio_init(&ioc, &cc.eng, stdin_read, &trace, stdout_write, &trace);
+
+	/*
+	 * Run the Twrch protocol.
+	 */
+	for (;;) {
+		br_sha1_context sc;
+		unsigned char hv[20], tmp[41];
+		uint64_t count;
+		int fb, i;
+
+		/*
+		 * Read line, byte by byte, hashing it on the fly.
+		 */
+		br_sha1_init(&sc);
+		count = 0;
+		fb = 0;
+		for (;;) {
+			unsigned char x;
+
+			if (br_sslio_read(&ioc, &x, 1) < 0) {
+				if (count == 0 && reconnect) {
+					reconnect = 0;
+					if (br_sslio_close(&ioc) < 0) {
+						goto twrch_loop_finished;
+					}
+					if (is_client) {
+						br_ssl_client_reset(
+							&cc.cnt, sni, 1);
+					}
+					if (is_server) {
+						br_ssl_server_reset(&cc.srv);
+					}
+					br_sslio_init(&ioc, &cc.eng,
+						stdin_read, &trace,
+						stdout_write, &trace);
+					continue;
+				}
+				goto twrch_loop_finished;
+			}
+			if (count == 0) {
+				fb = x;
+			}
+			if (x == 0x0A) {
+				break;
+			}
+			br_sha1_update(&sc, &x, 1);
+			count ++;
+		}
+		if (count == 1) {
+			switch (fb) {
+			case 'C':
+				br_sslio_close(&ioc);
+				goto twrch_loop_finished;
+			case 'T':
+				if (br_sslio_close(&ioc) < 0) {
+					goto twrch_loop_finished;
+				}
+				if (is_client) {
+					br_ssl_client_reset(&cc.cnt, sni, 1);
+				}
+				if (is_server) {
+					br_ssl_server_reset(&cc.srv);
+				}
+				br_sslio_init(&ioc, &cc.eng,
+					stdin_read, &trace,
+					stdout_write, &trace);
+				continue;
+			case 'G':
+				if (!br_ssl_engine_renegotiate(&cc.eng)) {
+					br_sslio_write_all(&ioc, "DENIED\n", 7);
+					br_sslio_flush(&ioc);
+				} else {
+					br_sslio_write_all(&ioc, "OK\n", 3);
+					br_sslio_flush(&ioc);
+				}
+				continue;
+			case 'R':
+				reconnect = 1;
+				br_sslio_write_all(&ioc, "OK\n", 3);
+				br_sslio_flush(&ioc);
+				continue;
+			case 'U':
+				if (is_client) {
+					br_ssl_client_forget_session(&cc.cnt);
+				}
+				if (is_server && cache != NULL) {
+					br_ssl_session_parameters pp;
+
+					br_ssl_engine_get_session_parameters(
+						&cc.eng, &pp);
+					if (pp.session_id_len == 32) {
+						br_ssl_session_cache_lru_forget(
+							&lru, pp.session_id);
+					}
+				}
+				br_sslio_write_all(&ioc, "DONE\n", 5);
+				br_sslio_flush(&ioc);
+				continue;
+			}
+		}
+		br_sha1_out(&sc, hv);
+		for (i = 0; i < 20; i ++) {
+			int x;
+
+			x = hv[i];
+			tmp[(i << 1) + 0] = "0123456789abcdef"[x >> 4];
+			tmp[(i << 1) + 1] = "0123456789abcdef"[x & 15];
+		}
+		tmp[40] = 0x0A;
+		br_sslio_write_all(&ioc, tmp, 41);
+		br_sslio_flush(&ioc);
+	}
+
+twrch_loop_finished:
+	if (br_ssl_engine_current_state(&cc.eng) == BR_SSL_CLOSED) {
+		int err;
+
+		err = br_ssl_engine_last_error(&cc.eng);
+		if (err == 0) {
+			retcode = 0;
+		} else {
+			if (verbose) {
+				print_error(err);
+			}
+			retcode = 1;
+		}
+	} else {
+		if (verbose) {
+			fprintf(stderr, "Engine not closed!\n");
+		}
+		retcode = 1;
+	}
+
+	/*
+	 * Release allocated structures.
+	 */
+twrch_exit:
+	xfree(suites);
+	xfree(suite_ids);
+	free_certificates(chain, chain_len);
+	free_private_key(sk);
+	VEC_CLEAREXT(anchors, &free_ta_contents);
+	VEC_CLEAREXT(alpn_names, &free_alpn);
+	xfree(iobuf);
+	xfree(cache);
+	return retcode;
+
+twrch_exit_error:
+	retcode = -1;
+	goto twrch_exit;
+}