proper signing, added ignorable/recoverable error

README

@@ -24,6 +24,9 @@ Functions:
 	; :read - There was an error reading the message
 	; :closed - The connection was closed before a message could be read
 	; :message - The message was invalid or outside the acceptable size bounds (TODO make this runtime instead of compile-time constant)
+	; :checksum - The message had an invalid checksum
+   ;; there are also ignorable/recoverable errors, which are sent to the error callback as suck '(:warning <error name>). These are treated differently. If the error callback returns T, let the message be carried on. If the error callback returns NIL, discard it. Available ones are:
+	; (:warning :checksum) - The message had no checksum. (note: if this is not allowed to pass then :CHECKSUM error is raised).
 	;; (see libsipc/include/sipc.h for more details)
    ;; available types are:
 	; :string - Normal string
@@ -129,7 +132,6 @@ Terminal 1:
 
 ---
 
-TODO: Add proper signing.
 TODO: Internal error handling.
 TODO: Have libsipc built on system load
 TODO: better .so loading

cl-sipc.asd

@@ -4,7 +4,7 @@
   :description "AF_UNIX IPC for CL"
   :author "Avril <flanchan@cumallover.me>"
   :license "None"
-  :version "0.0.3"
+  :version "0.0.4"
   :serial t
   :depends-on (  :cffi  )
   :components  ((:file "package")

cl-sipc.lisp

@@ -90,6 +90,7 @@
 	:error - send() error
 	:failure - send failed
 	:message - invalid response message
+	:checksum - invalid checksum
 	:unknown - unknown error code
 	:unknown-type - key argument :type is unknown
   :type can be:
@@ -125,7 +126,7 @@
 		(cond ((= rc #.+si-send-partial+) :partial)
 		      ((= rc #.+si-send-error+) :error)
 		      ((= rc #.+si-send-failure+) :failure)
-		      (t :unknown))))
+		      (t (marshal-ec rc)))))
       rc)))
 
 (defun respond (value &optional (type :string))
@@ -150,7 +151,7 @@
 		((= rc #.+si-send-partial+) :partial)
 		((= rc #.+si-send-error+) :error)
 		((= rc #.+si-send-failure+) :failure)
-		(t :unknown))
+		(t (marshal-ec rc)))
 	  rc))
       :response-invalid)))
 

ffi.lisp

@@ -15,6 +15,11 @@
 (defconstant +sie-r-invalid+ 4)
 (defconstant +sie-r-multi+ 5)
 (defconstant +sie-r-disable+ 6)
+(defconstant +sie-checksum+ 7)
+
+;; recoverable ("warning") error codes
+(defconstant +sief-warning+ #xAFF000)
+(defconstant +siw-checksum+ #.(+ +sief-warning+ 1))
 
 (defctype si-send-rc :int)
 (defconstant +si-send-okay+ 0)
@@ -51,13 +56,15 @@
 	((= err #.+sie-read+) :read)
 	((= err #.+sie-pconcls+) :closed)
 	((= err #.+sie-invalid+) :message)
+	((= err #.+sie-checksum+) :checksum)
+	((= err #.+siw-checksum+) '(:warning :checksum))
 	(t :unknown)))
 
 (defcallback si-error-callback :int ((err si-error))
   (when (symbol-value '*on-error*)
     (if (funcall (symbol-value '*on-error*) (marshal-ec err))
       0
-      1)))
+      -1)))
 
 (defun si-typecase (message &key string binary close)
   (let* ((type (sif-type message))
@@ -68,7 +75,7 @@
 		    ((= type #.+si-binary+) (funcall binary (make-pointer :memory data :size size))))))
     (if rval
       0
-      1)))
+      -1)))
 
 
 (defcallback si-callback :int ((message :pointer))

libsipc/include/sipc.h

@@ -1,6 +1,7 @@
 #ifndef _LIBSIPC_H
 #define _LIBSIPC_H
 #include <stddef.h>
+#include <stdint.h>
 
 #define SI_MAX_MESSAGE_SIZE 1024
 
@@ -21,19 +22,22 @@ typedef enum {
 	_SI_ERROR,
 } si_type;
 
-#define SI_NORESP (1<<0)
-#define SI_DISCARD (1<<1)
+#define SI_NORESP (1<<0)	//Do not expect a response.
+#define SI_DISCARD (1<<1)	//Do not process this.
+#define SI_NOSIGN (1<<2)	//This message is not signed.
 
-#define _SI_HEADER_CHECK 0xbeefbeefabad1dea;
+#define _SI_HEADER_CHECK 0xbeefbeefabad1deaul
 
 typedef struct {
 	si_type type;
 	unsigned int flags;
 	unsigned int data_len;
-	unsigned long check;
+	unsigned long check0;
+	uint64_t check;
 	unsigned char data[];
 } si_message;
 
+#define SIEF_WARNING  0xaff000
 typedef enum {
 	SIE_ACCEPT= 0, //Sock accept failure
 	SIE_READ, //Sock read failure
@@ -43,6 +47,12 @@ typedef enum {
 	SIE_R_INVALID, //This message cannot be responded to like that
 	SIE_R_MULTI, //A response has already been sent
 	SIE_R_DISABLE, //The client asked to not be responded to
+
+	SIE_CHECKSUM, //Bad checksum
+
+	//Recoverable errors (warnings)
+
+	SIW_CHECKSUM = (SIEF_WARNING)+1, //No checksum.
 } si_error;
 
 typedef int (*si_callback)(const si_message *msg);
@@ -60,7 +70,7 @@ char* si_type_string(si_type ty);
 int si_connect(const char* file); //Returns sd, or -1 on failure.
 int si_sendmsg_r(int sd, const si_message* msg,  si_message** response); //si_sendmmsg but optionally receive response (make sure to free() *response after you're done, NULL to discard response, if there is no response *response is not modified)
 int si_sendmsg(int sd, const si_message *msg); //Returns 0 on okay, 1 if whole message could not be sent, -1 on send error, -2 on weird send error. (see SI_SEND_*)
-void si_sign(si_message *msg); //Sign message. Use this before sending one.
+void si_sign(si_message *msg); //Sign message. Use this before sending one. (note: you still have to call this, even when setting SI_NOSIGN flag.
 
 //Quick funcs
 int siqs_string_r(int sd, const char* string, unsigned int flags, si_message** resp); //quick send string

libsipc/src/cli.c

@@ -6,6 +6,7 @@
 #include <string.h>
 
 int silent_level=0;
+int signing=1;
 
 #define Vprintf(...) if(silent_level<0) printf("[l] " __VA_ARGS__)
 #define Eprintf(...) if(silent_level <2) fprintf(stderr, "[e] " __VA_ARGS__)
@@ -13,7 +14,15 @@ int silent_level=0;
 
 int on_error(si_error err)
 {
+
+	if(err & SIEF_WARNING) { //Different handler for warnings
+		Eprintf("<- (w) %s\n", si_error_string(err));
+		if(err == SIW_CHECKSUM && signing) {
+			return -1; //We don't want to accept this, we're expecting signed packets.
+		} else return 0;
+	 } else {
 		Eprintf("<- %s\n", si_error_string(err));
+	 }
 
 	return 0;
 }
@@ -184,6 +193,8 @@ int client(const char* conto, const char* string, int bin)
 			Vprintf("timeout set to %d\n", timeout);
 		}
 		si_message *response = NULL;
+		if(!signing)
+			msg->flags |= SI_NOSIGN;	
 		si_sign(msg);
 		int rrc = si_sendmsg_r(sd, msg, &response);
 		if(response) {
@@ -221,6 +232,8 @@ int client_close(const char* conto)
 			Vprintf("timeout set to %d\n", timeout);
 		}
 		si_message* response = NULL;
+		if(!signing)
+			msg->flags |= SI_NOSIGN;	
 		si_sign(msg);
 		int rrc = si_sendmsg_r(sd, msg, &response);
 		if(response) {
@@ -256,6 +269,9 @@ int pfa(char** argv)
 			case 'v':
 				silent_level =-1;
 				break;
+			case 'u':
+				signing = 0;
+				break;
 			case 't':
 				nrc+=1;
 				timeout = atoi(*(argv+1+nrc));
@@ -343,7 +359,7 @@ int main(int argc, char** argv)
 	} else 
 	{
 		argv = _av;
-		printf("usage: %s [-qQvt] [<timeout>] -l[fe] <socket>\nusage: %s [-qQvt] [<timeout>] -p[b] <socket> <message>\nusage: %s [-qQvt] [<timeout>] -c[f] <socket>\nusage: %s [-qQvt] [<timeout>] -h <socket>\n", argv[0], argv[0], argv[0], argv[0]);
+		printf("usage: %s [-uqQvt] [<timeout>] -l[fe] <socket>\nusage: %s [-uqQvt] [<timeout>] -p[b] <socket> <message>\nusage: %s [-uqQvt] [<timeout>] -c[f] <socket>\nusage: %s [-qQvt] [<timeout>] -h <socket>\n", argv[0], argv[0], argv[0], argv[0]);
 		printf("\n-l[fe]\tlisten on socket. (f to unlink file first, e to send response)\n");
 		printf("-p[b]\twrite to socket. (b to send as binary)\n");
 		printf("-c[f]\tsend cose signal to socket. (f to unlink file after)\n");
@@ -353,6 +369,7 @@ int main(int argc, char** argv)
 		printf(" -Q\tsilent mode, only print responses\n");
 		printf(" -v\tverbose mode, print additional messages\n");
 		printf(" -t\tset socket timeout to next arg (in seconds)\n");
+		printf(" -u\tdo not sign messages (or do not verify, for server)\n");
 	}
 	return rc;
 }

libsipc/src/crc64.c

@@ -0,0 +1,191 @@
+/* Redis uses the CRC64 variant with "Jones" coefficients and init value of 0.
+ *
+ * Specification of this CRC64 variant follows:
+ * Name: crc-64-jones
+ * Width: 64 bites
+ * Poly: 0xad93d23594c935a9
+ * Reflected In: True
+ * Xor_In: 0xffffffffffffffff
+ * Reflected_Out: True
+ * Xor_Out: 0x0
+ * Check("123456789"): 0xe9c6d914c4b8d9ca
+ *
+ * Copyright (c) 2012, Salvatore Sanfilippo <antirez at gmail dot com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of Redis nor the names of its contributors may be used
+ *     to endorse or promote products derived from this software without
+ *     specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE. */
+
+#include <stdint.h>
+
+static const uint64_t crc64_tab[256] = {
+    UINT64_C(0x0000000000000000), UINT64_C(0x7ad870c830358979),
+    UINT64_C(0xf5b0e190606b12f2), UINT64_C(0x8f689158505e9b8b),
+    UINT64_C(0xc038e5739841b68f), UINT64_C(0xbae095bba8743ff6),
+    UINT64_C(0x358804e3f82aa47d), UINT64_C(0x4f50742bc81f2d04),
+    UINT64_C(0xab28ecb46814fe75), UINT64_C(0xd1f09c7c5821770c),
+    UINT64_C(0x5e980d24087fec87), UINT64_C(0x24407dec384a65fe),
+    UINT64_C(0x6b1009c7f05548fa), UINT64_C(0x11c8790fc060c183),
+    UINT64_C(0x9ea0e857903e5a08), UINT64_C(0xe478989fa00bd371),
+    UINT64_C(0x7d08ff3b88be6f81), UINT64_C(0x07d08ff3b88be6f8),
+    UINT64_C(0x88b81eabe8d57d73), UINT64_C(0xf2606e63d8e0f40a),
+    UINT64_C(0xbd301a4810ffd90e), UINT64_C(0xc7e86a8020ca5077),
+    UINT64_C(0x4880fbd87094cbfc), UINT64_C(0x32588b1040a14285),
+    UINT64_C(0xd620138fe0aa91f4), UINT64_C(0xacf86347d09f188d),
+    UINT64_C(0x2390f21f80c18306), UINT64_C(0x594882d7b0f40a7f),
+    UINT64_C(0x1618f6fc78eb277b), UINT64_C(0x6cc0863448deae02),
+    UINT64_C(0xe3a8176c18803589), UINT64_C(0x997067a428b5bcf0),
+    UINT64_C(0xfa11fe77117cdf02), UINT64_C(0x80c98ebf2149567b),
+    UINT64_C(0x0fa11fe77117cdf0), UINT64_C(0x75796f2f41224489),
+    UINT64_C(0x3a291b04893d698d), UINT64_C(0x40f16bccb908e0f4),
+    UINT64_C(0xcf99fa94e9567b7f), UINT64_C(0xb5418a5cd963f206),
+    UINT64_C(0x513912c379682177), UINT64_C(0x2be1620b495da80e),
+    UINT64_C(0xa489f35319033385), UINT64_C(0xde51839b2936bafc),
+    UINT64_C(0x9101f7b0e12997f8), UINT64_C(0xebd98778d11c1e81),
+    UINT64_C(0x64b116208142850a), UINT64_C(0x1e6966e8b1770c73),
+    UINT64_C(0x8719014c99c2b083), UINT64_C(0xfdc17184a9f739fa),
+    UINT64_C(0x72a9e0dcf9a9a271), UINT64_C(0x08719014c99c2b08),
+    UINT64_C(0x4721e43f0183060c), UINT64_C(0x3df994f731b68f75),
+    UINT64_C(0xb29105af61e814fe), UINT64_C(0xc849756751dd9d87),
+    UINT64_C(0x2c31edf8f1d64ef6), UINT64_C(0x56e99d30c1e3c78f),
+    UINT64_C(0xd9810c6891bd5c04), UINT64_C(0xa3597ca0a188d57d),
+    UINT64_C(0xec09088b6997f879), UINT64_C(0x96d1784359a27100),
+    UINT64_C(0x19b9e91b09fcea8b), UINT64_C(0x636199d339c963f2),
+    UINT64_C(0xdf7adabd7a6e2d6f), UINT64_C(0xa5a2aa754a5ba416),
+    UINT64_C(0x2aca3b2d1a053f9d), UINT64_C(0x50124be52a30b6e4),
+    UINT64_C(0x1f423fcee22f9be0), UINT64_C(0x659a4f06d21a1299),
+    UINT64_C(0xeaf2de5e82448912), UINT64_C(0x902aae96b271006b),
+    UINT64_C(0x74523609127ad31a), UINT64_C(0x0e8a46c1224f5a63),
+    UINT64_C(0x81e2d7997211c1e8), UINT64_C(0xfb3aa75142244891),
+    UINT64_C(0xb46ad37a8a3b6595), UINT64_C(0xceb2a3b2ba0eecec),
+    UINT64_C(0x41da32eaea507767), UINT64_C(0x3b024222da65fe1e),
+    UINT64_C(0xa2722586f2d042ee), UINT64_C(0xd8aa554ec2e5cb97),
+    UINT64_C(0x57c2c41692bb501c), UINT64_C(0x2d1ab4dea28ed965),
+    UINT64_C(0x624ac0f56a91f461), UINT64_C(0x1892b03d5aa47d18),
+    UINT64_C(0x97fa21650afae693), UINT64_C(0xed2251ad3acf6fea),
+    UINT64_C(0x095ac9329ac4bc9b), UINT64_C(0x7382b9faaaf135e2),
+    UINT64_C(0xfcea28a2faafae69), UINT64_C(0x8632586aca9a2710),
+    UINT64_C(0xc9622c4102850a14), UINT64_C(0xb3ba5c8932b0836d),
+    UINT64_C(0x3cd2cdd162ee18e6), UINT64_C(0x460abd1952db919f),
+    UINT64_C(0x256b24ca6b12f26d), UINT64_C(0x5fb354025b277b14),
+    UINT64_C(0xd0dbc55a0b79e09f), UINT64_C(0xaa03b5923b4c69e6),
+    UINT64_C(0xe553c1b9f35344e2), UINT64_C(0x9f8bb171c366cd9b),
+    UINT64_C(0x10e3202993385610), UINT64_C(0x6a3b50e1a30ddf69),
+    UINT64_C(0x8e43c87e03060c18), UINT64_C(0xf49bb8b633338561),
+    UINT64_C(0x7bf329ee636d1eea), UINT64_C(0x012b592653589793),
+    UINT64_C(0x4e7b2d0d9b47ba97), UINT64_C(0x34a35dc5ab7233ee),
+    UINT64_C(0xbbcbcc9dfb2ca865), UINT64_C(0xc113bc55cb19211c),
+    UINT64_C(0x5863dbf1e3ac9dec), UINT64_C(0x22bbab39d3991495),
+    UINT64_C(0xadd33a6183c78f1e), UINT64_C(0xd70b4aa9b3f20667),
+    UINT64_C(0x985b3e827bed2b63), UINT64_C(0xe2834e4a4bd8a21a),
+    UINT64_C(0x6debdf121b863991), UINT64_C(0x1733afda2bb3b0e8),
+    UINT64_C(0xf34b37458bb86399), UINT64_C(0x8993478dbb8deae0),
+    UINT64_C(0x06fbd6d5ebd3716b), UINT64_C(0x7c23a61ddbe6f812),
+    UINT64_C(0x3373d23613f9d516), UINT64_C(0x49aba2fe23cc5c6f),
+    UINT64_C(0xc6c333a67392c7e4), UINT64_C(0xbc1b436e43a74e9d),
+    UINT64_C(0x95ac9329ac4bc9b5), UINT64_C(0xef74e3e19c7e40cc),
+    UINT64_C(0x601c72b9cc20db47), UINT64_C(0x1ac40271fc15523e),
+    UINT64_C(0x5594765a340a7f3a), UINT64_C(0x2f4c0692043ff643),
+    UINT64_C(0xa02497ca54616dc8), UINT64_C(0xdafce7026454e4b1),
+    UINT64_C(0x3e847f9dc45f37c0), UINT64_C(0x445c0f55f46abeb9),
+    UINT64_C(0xcb349e0da4342532), UINT64_C(0xb1eceec59401ac4b),
+    UINT64_C(0xfebc9aee5c1e814f), UINT64_C(0x8464ea266c2b0836),
+    UINT64_C(0x0b0c7b7e3c7593bd), UINT64_C(0x71d40bb60c401ac4),
+    UINT64_C(0xe8a46c1224f5a634), UINT64_C(0x927c1cda14c02f4d),
+    UINT64_C(0x1d148d82449eb4c6), UINT64_C(0x67ccfd4a74ab3dbf),
+    UINT64_C(0x289c8961bcb410bb), UINT64_C(0x5244f9a98c8199c2),
+    UINT64_C(0xdd2c68f1dcdf0249), UINT64_C(0xa7f41839ecea8b30),
+    UINT64_C(0x438c80a64ce15841), UINT64_C(0x3954f06e7cd4d138),
+    UINT64_C(0xb63c61362c8a4ab3), UINT64_C(0xcce411fe1cbfc3ca),
+    UINT64_C(0x83b465d5d4a0eece), UINT64_C(0xf96c151de49567b7),
+    UINT64_C(0x76048445b4cbfc3c), UINT64_C(0x0cdcf48d84fe7545),
+    UINT64_C(0x6fbd6d5ebd3716b7), UINT64_C(0x15651d968d029fce),
+    UINT64_C(0x9a0d8ccedd5c0445), UINT64_C(0xe0d5fc06ed698d3c),
+    UINT64_C(0xaf85882d2576a038), UINT64_C(0xd55df8e515432941),
+    UINT64_C(0x5a3569bd451db2ca), UINT64_C(0x20ed197575283bb3),
+    UINT64_C(0xc49581ead523e8c2), UINT64_C(0xbe4df122e51661bb),
+    UINT64_C(0x3125607ab548fa30), UINT64_C(0x4bfd10b2857d7349),
+    UINT64_C(0x04ad64994d625e4d), UINT64_C(0x7e7514517d57d734),
+    UINT64_C(0xf11d85092d094cbf), UINT64_C(0x8bc5f5c11d3cc5c6),
+    UINT64_C(0x12b5926535897936), UINT64_C(0x686de2ad05bcf04f),
+    UINT64_C(0xe70573f555e26bc4), UINT64_C(0x9ddd033d65d7e2bd),
+    UINT64_C(0xd28d7716adc8cfb9), UINT64_C(0xa85507de9dfd46c0),
+    UINT64_C(0x273d9686cda3dd4b), UINT64_C(0x5de5e64efd965432),
+    UINT64_C(0xb99d7ed15d9d8743), UINT64_C(0xc3450e196da80e3a),
+    UINT64_C(0x4c2d9f413df695b1), UINT64_C(0x36f5ef890dc31cc8),
+    UINT64_C(0x79a59ba2c5dc31cc), UINT64_C(0x037deb6af5e9b8b5),
+    UINT64_C(0x8c157a32a5b7233e), UINT64_C(0xf6cd0afa9582aa47),
+    UINT64_C(0x4ad64994d625e4da), UINT64_C(0x300e395ce6106da3),
+    UINT64_C(0xbf66a804b64ef628), UINT64_C(0xc5bed8cc867b7f51),
+    UINT64_C(0x8aeeace74e645255), UINT64_C(0xf036dc2f7e51db2c),
+    UINT64_C(0x7f5e4d772e0f40a7), UINT64_C(0x05863dbf1e3ac9de),
+    UINT64_C(0xe1fea520be311aaf), UINT64_C(0x9b26d5e88e0493d6),
+    UINT64_C(0x144e44b0de5a085d), UINT64_C(0x6e963478ee6f8124),
+    UINT64_C(0x21c640532670ac20), UINT64_C(0x5b1e309b16452559),
+    UINT64_C(0xd476a1c3461bbed2), UINT64_C(0xaeaed10b762e37ab),
+    UINT64_C(0x37deb6af5e9b8b5b), UINT64_C(0x4d06c6676eae0222),
+    UINT64_C(0xc26e573f3ef099a9), UINT64_C(0xb8b627f70ec510d0),
+    UINT64_C(0xf7e653dcc6da3dd4), UINT64_C(0x8d3e2314f6efb4ad),
+    UINT64_C(0x0256b24ca6b12f26), UINT64_C(0x788ec2849684a65f),
+    UINT64_C(0x9cf65a1b368f752e), UINT64_C(0xe62e2ad306bafc57),
+    UINT64_C(0x6946bb8b56e467dc), UINT64_C(0x139ecb4366d1eea5),
+    UINT64_C(0x5ccebf68aecec3a1), UINT64_C(0x2616cfa09efb4ad8),
+    UINT64_C(0xa97e5ef8cea5d153), UINT64_C(0xd3a62e30fe90582a),
+    UINT64_C(0xb0c7b7e3c7593bd8), UINT64_C(0xca1fc72bf76cb2a1),
+    UINT64_C(0x45775673a732292a), UINT64_C(0x3faf26bb9707a053),
+    UINT64_C(0x70ff52905f188d57), UINT64_C(0x0a2722586f2d042e),
+    UINT64_C(0x854fb3003f739fa5), UINT64_C(0xff97c3c80f4616dc),
+    UINT64_C(0x1bef5b57af4dc5ad), UINT64_C(0x61372b9f9f784cd4),
+    UINT64_C(0xee5fbac7cf26d75f), UINT64_C(0x9487ca0fff135e26),
+    UINT64_C(0xdbd7be24370c7322), UINT64_C(0xa10fceec0739fa5b),
+    UINT64_C(0x2e675fb4576761d0), UINT64_C(0x54bf2f7c6752e8a9),
+    UINT64_C(0xcdcf48d84fe75459), UINT64_C(0xb71738107fd2dd20),
+    UINT64_C(0x387fa9482f8c46ab), UINT64_C(0x42a7d9801fb9cfd2),
+    UINT64_C(0x0df7adabd7a6e2d6), UINT64_C(0x772fdd63e7936baf),
+    UINT64_C(0xf8474c3bb7cdf024), UINT64_C(0x829f3cf387f8795d),
+    UINT64_C(0x66e7a46c27f3aa2c), UINT64_C(0x1c3fd4a417c62355),
+    UINT64_C(0x935745fc4798b8de), UINT64_C(0xe98f353477ad31a7),
+    UINT64_C(0xa6df411fbfb21ca3), UINT64_C(0xdc0731d78f8795da),
+    UINT64_C(0x536fa08fdfd90e51), UINT64_C(0x29b7d047efec8728),
+};
+
+uint64_t crc64(uint64_t crc, const unsigned char *s, uint64_t l) {
+    uint64_t j;
+
+    for (j = 0; j < l; j++) {
+        uint8_t byte = s[j];
+        crc = crc64_tab[(uint8_t)crc ^ byte] ^ (crc >> 8);
+    }
+    return crc;
+}
+
+/* Test main */
+#ifdef TEST_MAIN
+#include <stdio.h>
+int main(void) {
+    printf("e9c6d914c4b8d9ca == %016llx\n",
+        (unsigned long long) crc64(0,(unsigned char*)"123456789",9));
+    return 0;
+}
+#endif

libsipc/src/crc64.h

@@ -0,0 +1,7 @@
+#ifndef _CRC64_H
+#define _CRC64_H
+#include <stdint.h>
+
+uint64_t crc64(uint64_t crc, const unsigned char * s, uint64_t l);
+
+#endif /* _CRC64_H  */

libsipc/src/sipc.c

@@ -9,6 +9,7 @@
 #include <stdarg.h>
 
 #include <sipc.h>
+#include "crc64.h"
 
 #define _SIRH_CHECK 0xabad
 struct si_response_header {
@@ -42,10 +43,26 @@ int si_bind(const char* file)
 	return sd;
 }
 
+int si_validate_message(const si_message *msg)
+{
+	char buffer[sizeof(si_message)];
+
+	if(msg->flags & SI_NOSIGN)
+		return 0; //Don't bother checking if it says there's no sign.
+	
+	memset(buffer,0,sizeof(si_message));
+	si_message *head = (si_message*)buffer;
+	memcpy(buffer,msg,sizeof(si_message));
+	head->check = _SI_HEADER_CHECK;
+	uint64_t crc0 = crc64(0, (unsigned char*)head, sizeof(si_message));
+	uint64_t crc = crc64(crc0,  msg->data, head->data_len);
+	return msg->check == crc;
+}
+
 static int _si_valid_header(const si_message *msg)
 {
 	int kk = (int)msg->type;
-	return kk>=0 && kk<_SI_ERROR && msg->data_len < SI_MAX_MESSAGE_SIZE && msg->check == _SI_HEADER_CHECK;
+	return kk>=0 && kk<_SI_ERROR && msg->data_len < SI_MAX_MESSAGE_SIZE && msg->check0 == _SI_HEADER_CHECK;
 }
 
 static int _si_read_rest(int sd, si_message *message)
@@ -135,6 +152,7 @@ int si_listen(int sd, si_error_callback on_error, si_callback on_message)
 				memcpy(full, message, sizeof(si_message));
 
 				rc = _si_read_rest(csd, full);
+				int valid=0;
 
 				if(rc!=0) {
 					if(rc==-1)
@@ -147,9 +165,13 @@ int si_listen(int sd, si_error_callback on_error, si_callback on_message)
 						break;
 					}
 				}
-			  	else {
+			  	else if( (valid=si_validate_message(full)) || (full->flags & SI_NOSIGN) ){
 					//Message has been read.
 					
+					if(!valid) {
+						valid = on_error(SIW_CHECKSUM) == 0; 
+					}
+					if(valid) {
 						rc = (full->flags & SI_DISCARD) ? 0 : on_message(full);
 
 						if(!full0->resp_sent && !(full->flags & SI_NORESP))
@@ -168,6 +190,22 @@ int si_listen(int sd, si_error_callback on_error, si_callback on_message)
 							free(resp);
 
 						}
+					} else {
+						rc = on_error(SIE_CHECKSUM);
+						if(rc<0) 
+						{
+							close(csd);
+							free(full0);
+							break;
+						}
+					}
+				} else { // Bad checksum
+					rc = on_error(SIE_CHECKSUM);
+					if(rc<0) {
+						close(csd);
+						free(full0);
+						break;
+					}
 				}
 				free(full0);
 			}
@@ -207,13 +245,19 @@ char *si_error_string(si_error err)
 			put("SIE_INVALID: Bad message");
 			break;
 		case SIE_R_INVALID:
-			puts("SIE_R_INVALID: Cannot respond to this");
+			put("SIE_R_INVALID: Cannot respond to this");
 			break;
 		case SIE_R_MULTI:
-			puts("SIE_R_MULTI: A response has already been sent");
+			put("SIE_R_MULTI: A response has already been sent");
 			break;
 		case SIE_R_DISABLE:
-			puts("SIE_R_DISABLE: A response is not expected");
+			put("SIE_R_DISABLE: A response is not expected");
+			break;
+		case SIE_CHECKSUM:
+			put("SIE_CHECKSUM: Bad checksum");
+			break;
+		case SIW_CHECKSUM:
+			put("SIW_CHECKSUM: No checksum");
 			break;
 		default:
 			put("SIE_UNKNOWN: Unknown EC %d", (int)err);
@@ -299,13 +343,20 @@ int si_read_response(int sd, si_message** resp)
 		memset(full,0,sizeof(si_message)+head->data_len+1);
 		memcpy(full, head, sizeof(si_message));
 		rc = _si_read_rest(sd, full);
+		int valid=0;
 		switch(rc) {
 			case 0:
+
+				if((valid=si_validate_message(full)) || (full->flags & SI_NOSIGN)) {
 					if(full->flags & SI_DISCARD)
 						free(full);
 					else 
 						*resp = full;
-				return 0;
+					return valid?0:(int)SIW_CHECKSUM;
+				} else {
+					free(full);
+					return (int)SIE_CHECKSUM;
+				}
 			case -1:
 				free(full);
 				return (int)SIE_READ;
@@ -341,7 +392,10 @@ static int _si_sendmsg(int sd, const si_message* msg)
 
 void si_sign(si_message* msg)
 {
-	msg->check = _SI_HEADER_CHECK;
+	msg->check = (uint64_t)(msg->check0 = _SI_HEADER_CHECK);
+	if(msg->flags & SI_NOSIGN) return;
+	uint64_t crc = crc64(0, (unsigned char*)msg, sizeof(si_message)+msg->data_len);
+	msg->check = crc;
 }
 
 int si_sendmsg_r(int sd, const si_message *msg, si_message** resp)
@@ -543,3 +597,5 @@ int siqr_printf(const si_message* sd, const char* format, ...)
 
 	return rc;
 }
+
+#include "crc64.c" //why not keep single translation unit?

tools/test-server.lisp

@@ -6,6 +6,7 @@
 (defparameter *socket-file* "sipc.socket")
 (defparameter *timeout* 5) ;; read timeout in seconds.
 (defparameter *respond* t) ;; should the server echo responses to client?
+(defparameter *allow-no-checksums* t) ;; should we process unsigned messages?
 
 (when (probe-file *socket-file*)
   (delete-file *socket-file*))
@@ -22,7 +23,7 @@
 			#'(lambda (err) ;; Callback ran if there is an error
 			    (format t "[e] <- ~a~%" err)
 			    (force-output)
-			    t) ;;returning NIL to the listener stops, t lets it continue
+			    (or (atom err) *allow-no-checksums*) ) ;;returning NIL to the listener stops, t lets it continue. err will only be not atom() if it's a warning, which are handled differently. T lets the pipe continue and pass the message to the message callback, nil does not.
 			#'(lambda (type message) ;; Callback ran when a message is received
 			    (when *respond*
 			      (format t