MINOR: sample: Add be2dec converter

Add be2dec converter which allows to build JA3 compatible TLS
fingerprints by converting big-endian binary data into string
separated unsigned integers eg.

http-request set-header X-SSL-JA3 %[ssl_fc_protocol_hello_id],\
    %[ssl_fc_cipherlist_bin(1),be2dec(-,2)],\
    %[ssl_fc_extlist_bin(1),be2dec(-,2)],\
    %[ssl_fc_eclist_bin(1),be2dec(-,2)],\
    %[ssl_fc_ecformats_bin,be2dec(-,1)]

doc/configuration.txt

@@ -16092,6 +16092,19 @@ base64
   an SSL ID can be copied in a header). For base64url("URL and Filename
   Safe Alphabet" (RFC 4648)) variant see "ub64enc".
 
+be2dec(<separator>,<chunk_size>,[<truncate>])
+  Converts big-endian binary input sample to a string containing an unsigned
+  integer number per <chunk_size> input bytes. <separator> is put every
+  <chunk_size> binary input bytes if specified. <truncate> flag indicates
+  whatever binary input is truncated at <chunk_size> boundaries. <chunk_size>
+  maximum value is limited by the size of long long int (8 bytes).
+
+  Example:
+      bin(01020304050607),be2dec(:,2)   # 258:772:1286:7
+      bin(01020304050607),be2dec(-,2,1) # 258-772-1286
+      bin(01020304050607),be2dec(,2,1)  # 2587721286
+      bin(7f000001),be2dec(.,1)         # 127.0.0.1
+
 bool
   Returns a boolean TRUE if the input value of type signed integer is
   non-null, otherwise returns FALSE. Used in conjunction with and(), it can be

reg-tests/converter/be2dec.vtc

@@ -0,0 +1,56 @@
+varnishtest "be2dec converter Test"
+
+feature cmd "$HAPROXY_PROGRAM -cc 'version_atleast(2.5-dev0)'"
+feature ignore_unknown_macro
+
+server s1 {
+	rxreq
+	txresp
+} -repeat 3 -start
+
+haproxy h1 -conf {
+    defaults
+	mode http
+	timeout connect 1s
+	timeout client  1s
+	timeout server  1s
+
+    frontend fe
+	bind "fd@${fe}"
+
+	#### requests
+	http-request  set-var(txn.input) req.hdr(input)
+
+	http-response set-header be2dec-1   "%[var(txn.input),be2dec(:,1)]"
+	http-response set-header be2dec-2   "%[var(txn.input),be2dec(-,3)]"
+	http-response set-header be2dec-3   "%[var(txn.input),be2dec(::,3,1)]"
+
+	default_backend be
+
+    backend be
+	server s1 ${s1_addr}:${s1_port}
+} -start
+
+client c1 -connect ${h1_fe_sock} {
+	txreq -url "/" \
+	  -hdr "input:"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.be2dec-1 == ""
+	expect resp.http.be2dec-2 == ""
+	expect resp.http.be2dec-3 == ""
+	txreq -url "/" \
+	  -hdr "input: 0123456789"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.be2dec-1 == "48:49:50:51:52:53:54:55:56:57"
+	expect resp.http.be2dec-2 == "3158322-3355701-3553080-57"
+	expect resp.http.be2dec-3 == "3158322::3355701::3553080"
+	txreq -url "/" \
+	  -hdr "input: abcdefghijklmnopqrstuvwxyz"
+	rxresp
+	expect resp.status == 200
+	expect resp.http.be2dec-1 == "97:98:99:100:101:102:103:104:105:106:107:108:109:110:111:112:113:114:115:116:117:118:119:120:121:122"
+	expect resp.http.be2dec-2 == "6382179-6579558-6776937-6974316-7171695-7369074-7566453-7763832-31098"
+	expect resp.http.be2dec-3 == "6382179::6579558::6776937::6974316::7171695::7369074::7566453::7763832"
+} -run

src/sample.c

@@ -2059,6 +2059,70 @@ err:
 
 #endif /* USE_OPENSSL */
 
+static int sample_conv_be2dec_check(struct arg *args, struct sample_conv *conv,
+                                    const char *file, int line, char **err)
+{
+	if (args[1].data.sint <= 0 || args[1].data.sint > sizeof(unsigned long long)) {
+		memprintf(err, "chunk_size out of [1..%ld] range (%lld)", sizeof(unsigned long long), args[1].data.sint);
+		return 0;
+	}
+
+	if (args[2].data.sint != 0 && args[2].data.sint != 1) {
+		memprintf(err, "Unsupported truncate value (%lld)", args[2].data.sint);
+		return 0;
+	}
+
+	return 1;
+}
+
+/* Converts big-endian binary input sample to a string containing an unsigned
+ * integer number per <chunk_size> input bytes separated with <separator>.
+ * Optional <truncate> flag indicates if input is truncated at <chunk_size>
+ * boundaries.
+ * Arguments: separator (string), chunk_size (integer), truncate (0,1)
+ */
+static int sample_conv_be2dec(const struct arg *args, struct sample *smp, void *private)
+{
+	struct buffer *trash = get_trash_chunk();
+	const int last = args[2].data.sint ? smp->data.u.str.data - args[1].data.sint + 1 : smp->data.u.str.data;
+	int max_size = trash->size - 2;
+	int i;
+	int start;
+	int ptr = 0;
+	unsigned long long number;
+	char *pos;
+
+	trash->data = 0;
+
+	while (ptr < last && trash->data <= max_size) {
+		start = trash->data;
+		if (ptr) {
+			/* Add separator */
+			memcpy(trash->area + trash->data, args[0].data.str.area, args[0].data.str.data);
+			trash->data += args[0].data.str.data;
+		}
+		else
+			max_size -= args[0].data.str.data;
+
+		/* Add integer */
+		for (number = 0, i = 0; i < args[1].data.sint && ptr < smp->data.u.str.data; i++)
+			number = (number << 8) + (unsigned char)smp->data.u.str.area[ptr++];
+
+		pos = ulltoa(number, trash->area + trash->data, trash->size - trash->data);
+		if (pos)
+			trash->data = pos - trash->area;
+		else {
+			trash->data = start;
+			break;
+		}
+	}
+
+	smp->data.u.str = *trash;
+	smp->data.type = SMP_T_STR;
+	smp->flags &= ~SMP_F_CONST;
+	return 1;
+}
+
 static int sample_conv_bin2hex(const struct arg *arg_p, struct sample *smp, void *private)
 {
 	struct buffer *trash = get_trash_chunk();
@@ -4253,6 +4317,7 @@ static struct sample_conv_kw_list sample_conv_kws = {ILH, {
 	{ "upper",   sample_conv_str2upper,    0,                     NULL,                     SMP_T_STR,  SMP_T_STR  },
 	{ "lower",   sample_conv_str2lower,    0,                     NULL,                     SMP_T_STR,  SMP_T_STR  },
 	{ "length",  sample_conv_length,       0,                     NULL,                     SMP_T_STR,  SMP_T_SINT },
+	{ "be2dec",  sample_conv_be2dec,       ARG3(1,STR,SINT,SINT), sample_conv_be2dec_check, SMP_T_BIN,  SMP_T_STR  },
 	{ "hex",     sample_conv_bin2hex,      0,                     NULL,                     SMP_T_BIN,  SMP_T_STR  },
 	{ "hex2i",   sample_conv_hex2int,      0,                     NULL,                     SMP_T_STR,  SMP_T_SINT },
 	{ "ipmask",  sample_conv_ipmask,       ARG2(1,MSK4,MSK6),     NULL,                     SMP_T_ADDR, SMP_T_IPV4 },