lib: Exchange protocol info during CACEP

This exchanges a protocol name, a protocol version and concrete syntax
for the protocol upon CACEP. For CDAP, only version 1 and GPB are
supported. No lists for other supported versions or syntaxes are
exchanged (but the proto file supports it). CACEP fails if there is a
mismatch between the protocol names, version and syntax specified by
the communicating parties.

14 files changed, 470 insertions, 31 deletions

diff --git a/include/ouroboros/cacep.h b/include/ouroboros/cacep.h
index 63418bd3..e0737c47 100644
--- a/include/ouroboros/cacep.h
+++ b/include/ouroboros/cacep.h
@@ -26,12 +26,27 @@
 
 #include <ouroboros/irm_config.h>
 
+enum proto_concrete_syntax {
+        PROTO_GPB = 0,
+        PROTO_ASN_1,
+        PROTO_FIXED
+};
+
 struct cacep_info {
+        struct {
+                char *                     protocol;
+                uint32_t                   pref_version;
+                enum proto_concrete_syntax pref_syntax;
+        }        proto;
         char *   name;
         uint64_t addr;
         void *   data;
 };
 
+int                 cacep_info_init(struct cacep_info * info);
+
+void                cacep_info_fini(struct cacep_info * info);
+
 struct cacep_info * cacep_auth(int                       fd,
                                enum pol_cacep            pc,
                                const struct cacep_info * info);
diff --git a/include/ouroboros/cdap.h b/include/ouroboros/cdap.h
index 9f6e2654..cc04cf27 100644
--- a/include/ouroboros/cdap.h
+++ b/include/ouroboros/cdap.h
@@ -31,6 +31,7 @@
 #define F_SYNC 0x0001
 
 #define INVALID_CDAP_KEY -1
+#define CDAP_PROTO "CDAP"
 
 enum cdap_opcode {
         CDAP_READ = 0,
diff --git a/src/ipcpd/normal/cdap_flow.c b/src/ipcpd/normal/cdap_flow.c
index 2895af0d..a94627c2 100644
--- a/src/ipcpd/normal/cdap_flow.c
+++ b/src/ipcpd/normal/cdap_flow.c
@@ -37,12 +37,9 @@ static void cdap_flow_destroy(struct cdap_flow * flow)
 
         if (flow->ci != NULL)
                 cdap_destroy(flow->ci);
-
         if (flow->info != NULL) {
-                if (flow->info->name != NULL)
-                        free(flow->info->name);
-                if (flow->info->data != NULL)
-                        free(flow->info->data);
+                cacep_info_fini(flow->info);
+                free(flow->info);
         }
 
         free(flow);
diff --git a/src/ipcpd/normal/enroll.c b/src/ipcpd/normal/enroll.c
index e8c085a8..ce6768fb 100644
--- a/src/ipcpd/normal/enroll.c
+++ b/src/ipcpd/normal/enroll.c
@@ -26,6 +26,7 @@
 #include <ouroboros/dev.h>
 #include <ouroboros/logs.h>
 #include <ouroboros/rib.h>
+#include <ouroboros/errno.h>
 
 #include "ae.h"
 #include "cdap_flow.h"
@@ -43,6 +44,7 @@
 int enroll_handle(int fd)
 {
         struct cdap_flow * flow;
+        struct cacep_info  info;
         cdap_key_t         key;
         enum cdap_opcode   oc;
         char *             name;
@@ -59,13 +61,27 @@ int enroll_handle(int fd)
         char * members_ro = MEMBERS_PATH;
         char * dif_ro     = DIF_PATH;
 
-        flow = cdap_flow_arr(fd, 0, ANONYMOUS_AUTH, NULL);
+        cacep_info_init(&info);
+
+        info.proto.protocol = strdup(CDAP_PROTO);
+        if (info.proto.protocol == NULL) {
+                cacep_info_fini(&info);
+                return -ENOMEM;
+        }
+
+        info.proto.pref_version = 1;
+        info.proto.pref_syntax  = PROTO_GPB;
+
+        flow = cdap_flow_arr(fd, 0, ANONYMOUS_AUTH, &info);
         if (flow == NULL) {
                 log_err("Failed to auth enrollment request.");
+                cacep_info_fini(&info);
                 flow_dealloc(fd);
                 return -1;
         }
 
+        cacep_info_fini(&info);
+
         while (!(boot_r && members_r && dif_name_r)) {
                 key = cdap_request_wait(flow->ci, &oc, &name, &data,
                                         (size_t *) &len , &flags);
@@ -140,6 +156,7 @@ int enroll_handle(int fd)
 int enroll_boot(char * dst_name)
 {
         struct cdap_flow * flow;
+        struct cacep_info  info;
         cdap_key_t         key;
         uint8_t *          data;
         size_t             len;
@@ -153,12 +170,27 @@ int enroll_boot(char * dst_name)
         char * members_ro = MEMBERS_PATH;
         char * dif_ro     = DIF_PATH;
 
-        flow = cdap_flow_alloc(dst_name, ENROLL_AE, NULL, ANONYMOUS_AUTH, NULL);
+        cacep_info_init(&info);
+
+        info.proto.protocol = strdup(CDAP_PROTO);
+        if (info.proto.protocol == NULL) {
+                cacep_info_fini(&info);
+                return -ENOMEM;
+        }
+
+        info.proto.pref_version = 1;
+        info.proto.pref_syntax  = PROTO_GPB;
+
+        flow = cdap_flow_alloc(dst_name, ENROLL_AE, NULL, ANONYMOUS_AUTH,
+                               &info);
         if (flow == NULL) {
                 log_err("Failed to allocate flow for enrollment request.");
+                cacep_info_fini(&info);
                 return -1;
         }
 
+        cacep_info_fini(&info);
+
         log_dbg("Getting boot information from %s.", dst_name);
 
         clock_gettime(CLOCK_REALTIME, &t0);
diff --git a/src/ipcpd/normal/gam.c b/src/ipcpd/normal/gam.c
index bc71f0d8..791cf34e 100644
--- a/src/ipcpd/normal/gam.c
+++ b/src/ipcpd/normal/gam.c
@@ -23,6 +23,7 @@
 #define OUROBOROS_PREFIX "graph-adjacency-manager"
 
 #include <ouroboros/config.h>
+#include <ouroboros/cdap.h>
 #include <ouroboros/dev.h>
 #include <ouroboros/logs.h>
 #include <ouroboros/list.h>
@@ -181,32 +182,48 @@ int gam_flow_arr(struct gam * instance,
         struct cacep_info * rcv_info;
         struct cacep_info   snd_info;
 
-        snd_info.name = ipcpi.name;
-        snd_info.addr = ipcpi.address;
-        snd_info.data = NULL;
-
         if (flow_alloc_resp(fd, instance->ops->accept_new_flow(instance->ops_o))
             < 0) {
                 log_err("Could not respond to new flow.");
                 return -1;
         }
 
+        cacep_info_init(&snd_info);
+        snd_info.proto.protocol = strdup(CDAP_PROTO);
+        if (snd_info.proto.protocol == NULL) {
+                cacep_info_fini(&snd_info);
+                return -ENOMEM;
+        }
+
+        snd_info.proto.pref_version = 1;
+        snd_info.proto.pref_syntax = PROTO_GPB;
+        snd_info.addr = ipcpi.address;
+        snd_info.name = strdup(ipcpi.name);
+        if (snd_info.name == NULL) {
+                cacep_info_fini(&snd_info);
+                return -ENOMEM;
+        }
+
         rcv_info = cacep_auth_wait(fd, SIMPLE_AUTH, &snd_info);
         if (rcv_info == NULL) {
                 log_err("Other side failed to authenticate.");
+                cacep_info_fini(&snd_info);
                 return -1;
         }
 
+        cacep_info_fini(&snd_info);
+
         if (instance->ops->accept_flow(instance->ops_o, qs, rcv_info)) {
                 flow_dealloc(fd);
-                free(rcv_info->name);
+                cacep_info_fini(rcv_info);
                 free(rcv_info);
                 return 0;
         }
 
         if (add_ga(instance, fd, qs, rcv_info)) {
                 log_err("Failed to add ga to graph adjacency manager list.");
-                free(rcv_info->name);
+                flow_dealloc(fd);
+                cacep_info_fini(rcv_info);
                 free(rcv_info);
                 return -1;
         }
@@ -222,9 +239,7 @@ int gam_flow_alloc(struct gam * instance,
         struct cacep_info   snd_info;
         int                 fd;
 
-        snd_info.name = ipcpi.name;
-        snd_info.addr = ipcpi.address;
-        snd_info.data = NULL;
+        log_dbg("Allocating flow to %s.", dst_name);
 
         fd = flow_alloc(dst_name, instance->ae_name, NULL);
         if (fd < 0) {
@@ -238,22 +253,42 @@ int gam_flow_alloc(struct gam * instance,
                 return -1;
         }
 
+        cacep_info_init(&snd_info);
+        snd_info.proto.protocol = strdup(CDAP_PROTO);
+        if (snd_info.proto.protocol == NULL) {
+                cacep_info_fini(&snd_info);
+                return -ENOMEM;
+        }
+
+        snd_info.proto.pref_version = 1;
+        snd_info.proto.pref_syntax = PROTO_GPB;
+        snd_info.addr = ipcpi.address;
+        snd_info.name = strdup(ipcpi.name);
+        if (snd_info.name == NULL) {
+                cacep_info_fini(&snd_info);
+                return -ENOMEM;
+        }
+
         rcv_info = cacep_auth(fd, SIMPLE_AUTH, &snd_info);
         if (rcv_info == NULL) {
                 log_err("Other side failed to authenticate.");
+                cacep_info_fini(&snd_info);
                 return -1;
         }
 
+        cacep_info_fini(&snd_info);
+
         if (instance->ops->accept_flow(instance->ops_o, qs, rcv_info)) {
                 flow_dealloc(fd);
-                free(rcv_info->name);
+                cacep_info_fini(rcv_info);
                 free(rcv_info);
                 return 0;
         }
 
         if (add_ga(instance, fd, qs, rcv_info)) {
                 log_err("Failed to add GA to graph adjacency manager list.");
-                free(rcv_info->name);
+                flow_dealloc(fd);
+                cacep_info_fini(rcv_info);
                 free(rcv_info);
                 return -1;
         }
diff --git a/src/lib/CMakeLists.txt b/src/lib/CMakeLists.txt
index f823b2d1..fcea0fb2 100644
--- a/src/lib/CMakeLists.txt
+++ b/src/lib/CMakeLists.txt
@@ -10,6 +10,10 @@ protobuf_generate_c(DIF_CONFIG_PROTO_SRCS DIF_CONFIG_PROTO_HDRS
   dif_config.proto)
 protobuf_generate_c(CDAP_PROTO_SRCS CDAP_PROTO_HDRS cdap.proto)
 protobuf_generate_c(RO_PROTO_SRCS RO_PROTO_HDRS ro.proto)
+protobuf_generate_c(CACEP_PROTO_PROTO_SRCS CACEP_CDAP_PROTO_HDRS
+  pol/cacep_proto.proto)
+protobuf_generate_c(CACEP_ANONYMOUS_AUTH_PROTO_SRCS
+  CACEP_ANONYMOUS_AUTH_PROTO_HDRS pol/cacep_anonymous_auth.proto)
 protobuf_generate_c(CACEP_SIMPLE_AUTH_PROTO_SRCS CACEP_SIMPLE_AUTH_PROTO_HDRS
   pol/cacep_simple_auth.proto)
 
@@ -51,12 +55,14 @@ set(SOURCE_FILES
   time_utils.c
   utils.c
   # Add policies last
+  pol/cacep_proto.c
   pol/cacep_anonymous_auth.c
   pol/cacep_simple_auth.c
   )
 
 add_library(ouroboros SHARED ${SOURCE_FILES} ${IRM_PROTO_SRCS}
   ${IPCP_PROTO_SRCS} ${DIF_CONFIG_PROTO_SRCS} ${CDAP_PROTO_SRCS}
+  ${CACEP_PROTO_PROTO_SRCS} ${CACEP_ANONYMOUS_AUTH_PROTO_SRCS}
   ${CACEP_SIMPLE_AUTH_PROTO_SRCS} ${RO_PROTO_SRCS})
 
 target_link_libraries(ouroboros ${LIBRT_LIBRARIES}
diff --git a/src/lib/cacep.c b/src/lib/cacep.c
index 3d556d8f..92c028af 100644
--- a/src/lib/cacep.c
+++ b/src/lib/cacep.c
@@ -36,10 +36,40 @@
 
 #define BUF_SIZE 2048
 
+int cacep_info_init(struct cacep_info * info)
+{
+        if (info == NULL)
+                return -EINVAL;
+
+        info->proto.protocol = NULL;
+        info->name           = NULL;
+        info->data           = NULL;
+
+        return 0;
+}
+
+void cacep_info_fini(struct cacep_info * info)
+{
+        if (info->proto.protocol != NULL)
+                free(info->proto.protocol);
+        if (info->name != NULL)
+                free(info->name);
+        if (info->data != NULL)
+                free(info->data);
+
+        info->name = NULL;
+        info->data = NULL;
+}
+
 struct cacep_info * cacep_auth(int                       fd,
                                enum pol_cacep            pc,
                                const struct cacep_info * info)
 {
+        if (info == NULL) {
+                log_err("No info provided.");
+                return NULL;
+        }
+
         switch (pc) {
         case ANONYMOUS_AUTH:
                 return cacep_anonymous_auth(fd, info);
@@ -57,6 +87,11 @@ struct cacep_info * cacep_auth_wait(int                       fd,
                                     enum pol_cacep            pc,
                                     const struct cacep_info * info)
 {
+        if (info == NULL) {
+                log_err("No info provided.");
+                return NULL;
+        }
+
         switch (pc) {
         case ANONYMOUS_AUTH:
                  return cacep_anonymous_auth_wait(fd, info);
diff --git a/src/lib/pol/cacep_anonymous_auth.c b/src/lib/pol/cacep_anonymous_auth.c
index d450fdc5..1ad8a533 100644
--- a/src/lib/pol/cacep_anonymous_auth.c
+++ b/src/lib/pol/cacep_anonymous_auth.c
@@ -24,7 +24,10 @@
 #include <ouroboros/config.h>
 #include <ouroboros/cacep.h>
 #include <ouroboros/time_utils.h>
+#include <ouroboros/dev.h>
+#include <ouroboros/errno.h>
 
+#include "cacep_proto.h"
 #include "cacep_anonymous_auth.h"
 
 #include <stdlib.h>
@@ -32,6 +35,11 @@
 #include <string.h>
 #include <stdio.h>
 
+#include "cacep_anonymous_auth.pb-c.h"
+typedef CacepAnonymousAuthMsg cacep_anonymous_auth_msg_t;
+typedef CacepProtoMsg cacep_proto_msg_t;
+
+#define BUF_SIZE 2048
 #define NAME_LEN 8
 
 /* this policy generates a hex string */
@@ -61,21 +69,130 @@ static struct cacep_info * anonymous_info(void)
         return info;
 }
 
+static struct cacep_info * read_msg(int fd)
+{
+        struct cacep_info *          tmp;
+        uint8_t                      buf[BUF_SIZE];
+        cacep_anonymous_auth_msg_t * msg;
+        ssize_t                      len;
+
+        len = flow_read(fd, buf, BUF_SIZE);
+        if (len < 0)
+                return NULL;
+
+        msg = cacep_anonymous_auth_msg__unpack(NULL, len, buf);
+        if (msg == NULL)
+                return NULL;
+
+        tmp = anonymous_info();
+        if (tmp == NULL) {
+                cacep_anonymous_auth_msg__free_unpacked(msg, NULL);
+                return NULL;
+        }
+
+        tmp->proto.protocol = strdup(msg->proto->protocol);
+        if (tmp->proto.protocol == NULL) {
+                free(tmp);
+                cacep_anonymous_auth_msg__free_unpacked(msg, NULL);
+                return NULL;
+        }
+
+        tmp->proto.pref_version = msg->proto->pref_version;
+        tmp->proto.pref_syntax  = code_to_syntax(msg->proto->pref_syntax);
+        if (tmp->proto.pref_syntax < 0) {
+                free(tmp->proto.protocol);
+                free(tmp);
+                cacep_anonymous_auth_msg__free_unpacked(msg, NULL);
+                return NULL;
+        }
+
+        cacep_anonymous_auth_msg__free_unpacked(msg, NULL);
+
+        return tmp;
+}
+
+static int send_msg(int                       fd,
+                    const struct cacep_info * info)
+{
+        cacep_anonymous_auth_msg_t msg  = CACEP_ANONYMOUS_AUTH_MSG__INIT;
+        cacep_proto_msg_t          cmsg = CACEP_PROTO_MSG__INIT;
+        int                        ret  = 0;
+        uint8_t *                  data = NULL;
+        size_t                     len  = 0;
+
+        cmsg.protocol     = info->proto.protocol;
+        cmsg.pref_version = info->proto.pref_version;
+        cmsg.pref_syntax  = syntax_to_code(info->proto.pref_syntax);
+        if (cmsg.pref_syntax < 0)
+                return -1;
+
+        msg.proto = &cmsg;
+
+        len = cacep_anonymous_auth_msg__get_packed_size(&msg);
+        if (len == 0)
+                return -1;
+
+        data = malloc(len);
+        if (data == NULL)
+                return -ENOMEM;
+
+        cacep_anonymous_auth_msg__pack(&msg, data);
+
+        if (flow_write(fd, data, len) < 0)
+                ret = -1;
+
+        free(data);
+
+        return ret;
+}
+
 struct cacep_info * cacep_anonymous_auth(int                       fd,
                                          const struct cacep_info * info)
 {
-        (void) fd;
-        (void) info;
+        struct cacep_info * tmp;
 
-        return anonymous_info();
+        if (send_msg(fd, info))
+                return NULL;
+
+        tmp = read_msg(fd);
+        if (tmp == NULL)
+                return NULL;
+
+        if (strcmp(info->proto.protocol, tmp->proto.protocol) ||
+            info->proto.pref_version != tmp->proto.pref_version ||
+            info->proto.pref_syntax != tmp->proto.pref_syntax) {
+                free(tmp);
+                return NULL;
+        }
+
+        tmp->data = NULL;
+
+        return tmp;
 }
 
 
 struct cacep_info * cacep_anonymous_auth_wait(int                       fd,
                                               const struct cacep_info * info)
 {
-        (void) fd;
-        (void) info;
+        struct cacep_info * tmp;
+
+        tmp = read_msg(fd);
+        if (tmp == NULL)
+                return NULL;
+
+        if (send_msg(fd, info)) {
+                free(tmp);
+                return NULL;
+        }
+
+        if (strcmp(info->proto.protocol, tmp->proto.protocol) ||
+            info->proto.pref_version != tmp->proto.pref_version ||
+            info->proto.pref_syntax != tmp->proto.pref_syntax) {
+                free(tmp);
+                return NULL;
+        }
+
+        tmp->data = NULL;
 
-        return anonymous_info();
+        return tmp;
 }
diff --git a/src/lib/pol/cacep_anonymous_auth.proto b/src/lib/pol/cacep_anonymous_auth.proto
new file mode 100644
index 00000000..79734e28
--- /dev/null
+++ b/src/lib/pol/cacep_anonymous_auth.proto
@@ -0,0 +1,30 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2017
+ *
+ * Message for no authentication CACEP policy
+ *
+ *    Dimitri Staessens <[email protected]>
+ *    Sander Vrijders   <[email protected]>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+syntax = "proto2";
+
+import "cacep_proto.proto";
+
+message cacep_anonymous_auth_msg {
+        required cacep_proto_msg proto = 1;
+}
\ No newline at end of file
diff --git a/src/lib/pol/cacep_proto.c b/src/lib/pol/cacep_proto.c
new file mode 100644
index 00000000..9990a05a
--- /dev/null
+++ b/src/lib/pol/cacep_proto.c
@@ -0,0 +1,52 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2017
+ *
+ * CACEP - Read/Write Protocol info
+ *
+ *    Sander Vrijders   <[email protected]>
+ *    Dimitri Staessens <[email protected]>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#include "cacep_proto.h"
+
+enum proto_concrete_syntax code_to_syntax(int code)
+{
+        switch(code) {
+        case PROTO_CONCRETE_SYNTAX_CODE__GPB:
+                return PROTO_GPB;
+        case PROTO_CONCRETE_SYNTAX_CODE__ASN_1:
+                return PROTO_ASN_1;
+        case PROTO_CONCRETE_SYNTAX_CODE__FIXED:
+                return PROTO_FIXED;
+        default:
+                return -1;
+        }
+}
+
+int syntax_to_code(enum proto_concrete_syntax stx)
+{
+        switch(stx) {
+        case PROTO_GPB:
+                return PROTO_CONCRETE_SYNTAX_CODE__GPB;
+        case PROTO_ASN_1:
+                return PROTO_CONCRETE_SYNTAX_CODE__ASN_1;
+        case PROTO_FIXED:
+                return PROTO_CONCRETE_SYNTAX_CODE__FIXED;
+        default:
+                return -1;
+        }
+}
diff --git a/src/lib/pol/cacep_proto.h b/src/lib/pol/cacep_proto.h
new file mode 100644
index 00000000..bfb1b247
--- /dev/null
+++ b/src/lib/pol/cacep_proto.h
@@ -0,0 +1,36 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2017
+ *
+ * CACEP - Convert syntax to msg code and back
+ *
+ *    Sander Vrijders   <[email protected]>
+ *    Dimitri Staessens <[email protected]>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#ifndef OUROBOROS_LIB_CACEP_CDAP_H
+#define OUROBOROS_LIB_CACEP_CDAP_H
+
+#include <ouroboros/cacep.h>
+#include <ouroboros/irm_config.h>
+
+#include "cacep_proto.pb-c.h"
+
+enum proto_concrete_syntax code_to_syntax(int code);
+
+int                        syntax_to_code(enum proto_concrete_syntax stx);
+
+#endif /* OUROBOROS_LIB_CACEP_CDAP_H */
diff --git a/src/lib/pol/cacep_proto.proto b/src/lib/pol/cacep_proto.proto
new file mode 100644
index 00000000..f313bfc1
--- /dev/null
+++ b/src/lib/pol/cacep_proto.proto
@@ -0,0 +1,38 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2017
+ *
+ * Message for setting Protocol information in CACEP
+ *
+ *    Dimitri Staessens <[email protected]>
+ *    Sander Vrijders   <[email protected]>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+syntax = "proto2";
+
+enum proto_concrete_syntax_code {
+        GPB   = 1;
+        ASN_1 = 2;
+        FIXED = 3;
+}
+
+message cacep_proto_msg {
+        required string protocol                        = 1;
+        required int32 pref_version                     = 2;
+        repeated int32 supp_version                     = 3;
+        required proto_concrete_syntax_code pref_syntax = 4;
+        repeated proto_concrete_syntax_code supp_syntax = 5;
+}
diff --git a/src/lib/pol/cacep_simple_auth.c b/src/lib/pol/cacep_simple_auth.c
index 1e052f3d..b24a818b 100644
--- a/src/lib/pol/cacep_simple_auth.c
+++ b/src/lib/pol/cacep_simple_auth.c
@@ -26,6 +26,7 @@
 #include <ouroboros/dev.h>
 #include <ouroboros/errno.h>
 
+#include "cacep_proto.h"
 #include "cacep_simple_auth.h"
 
 #include <stdlib.h>
@@ -33,6 +34,7 @@
 
 #include "cacep_simple_auth.pb-c.h"
 typedef CacepSimpleAuthMsg cacep_simple_auth_msg_t;
+typedef CacepProtoMsg cacep_proto_msg_t;
 
 #define BUF_SIZE 2048
 
@@ -65,6 +67,24 @@ static struct cacep_info * read_msg(int fd)
                 return NULL;
         }
 
+        tmp->proto.protocol = strdup(msg->proto->protocol);
+        if (tmp->proto.protocol == NULL) {
+                free(tmp->name);
+                free(tmp);
+                cacep_simple_auth_msg__free_unpacked(msg, NULL);
+                return NULL;
+        }
+
+        tmp->proto.pref_version = msg->proto->pref_version;
+        tmp->proto.pref_syntax  = code_to_syntax(msg->proto->pref_syntax);
+        if (tmp->proto.pref_syntax < 0) {
+                free(tmp->proto.protocol);
+                free(tmp->name);
+                free(tmp);
+                cacep_simple_auth_msg__free_unpacked(msg, NULL);
+                return NULL;
+        }
+
         cacep_simple_auth_msg__free_unpacked(msg, NULL);
 
         return tmp;
@@ -73,13 +93,21 @@ static struct cacep_info * read_msg(int fd)
 static int send_msg(int                       fd,
                     const struct cacep_info * info)
 {
-        cacep_simple_auth_msg_t msg = CACEP_SIMPLE_AUTH_MSG__INIT;
-        int                     ret = 0;
+        cacep_simple_auth_msg_t msg  = CACEP_SIMPLE_AUTH_MSG__INIT;
+        cacep_proto_msg_t       cmsg = CACEP_PROTO_MSG__INIT;
+        int                     ret  = 0;
         uint8_t *               data = NULL;
-        size_t                  len = 0;
+        size_t                  len  = 0;
 
-        msg.name = info->name;
-        msg.addr = info->addr;
+        cmsg.protocol     = info->proto.protocol;
+        cmsg.pref_version = info->proto.pref_version;
+        cmsg.pref_syntax  = syntax_to_code(info->proto.pref_syntax);
+        if (cmsg.pref_syntax < 0)
+                return -1;
+
+        msg.proto = &cmsg;
+        msg.name  = info->name;
+        msg.addr  = info->addr;
 
         len = cacep_simple_auth_msg__get_packed_size(&msg);
         if (len == 0)
@@ -113,6 +141,13 @@ struct cacep_info * cacep_simple_auth_auth(int                       fd,
         if (tmp == NULL)
                 return NULL;
 
+        if (strcmp(info->proto.protocol, tmp->proto.protocol) ||
+            info->proto.pref_version != tmp->proto.pref_version ||
+            info->proto.pref_syntax != tmp->proto.pref_syntax) {
+                free(tmp);
+                return NULL;
+        }
+
         return tmp;
 }
 
@@ -133,5 +168,12 @@ struct cacep_info * cacep_simple_auth_auth_wait(int                       fd,
                 return NULL;
         }
 
+        if (strcmp(info->proto.protocol, tmp->proto.protocol) ||
+            info->proto.pref_version != tmp->proto.pref_version ||
+            info->proto.pref_syntax != tmp->proto.pref_syntax) {
+                free(tmp);
+                return NULL;
+        }
+
         return tmp;
 }
diff --git a/src/lib/pol/cacep_simple_auth.proto b/src/lib/pol/cacep_simple_auth.proto
index d20f8780..1a1e7ea8 100644
--- a/src/lib/pol/cacep_simple_auth.proto
+++ b/src/lib/pol/cacep_simple_auth.proto
@@ -23,7 +23,10 @@
 
 syntax = "proto2";
 
+import "cacep_proto.proto";
+
 message cacep_simple_auth_msg {
-        required string name = 1;
-        required uint64 addr = 2;
+        required cacep_proto_msg proto = 1;
+        required string name           = 2;
+        required uint64 addr           = 3;
 }