project: Introduce actual connections

Signed-off-by: Ian Moffett <ian@osmora.org>

5 files changed, 286 insertions, 1 deletions

diff --git a/client/main.c b/client/main.c
index e6fcb7a..6bc5a5e 100644
--- a/client/main.c
+++ b/client/main.c
@@ -28,8 +28,10 @@
  */
 
 #include <net/stpsession.h>
+#include <net/param.h>
 #include <crypto/ecdh.h>
 #include <arpa/inet.h>
+#include <defs.h>
 #include <stdio.h>
 #include <stdint.h>
 #include <unistd.h>
@@ -38,6 +40,13 @@
 #define CENTRAL_SERVER "149.248.6.149"
 #define OSTP_PORT 5352
 
+static const char *pap_codestr[] = {
+    [PAP_SUCCESS]   = "success",
+    [PAP_BAD_SPW]   = "bad SPW",
+    [PAP_BAD_PERMS] = "insufficient permissions",
+    [PAP_RESOURCE]  = "server out of resources"
+};
+
 static void
 log_pubkey(uint8_t pubkey[])
 {
@@ -51,11 +60,72 @@ log_pubkey(uint8_t pubkey[])
 }
 
 static int
+negotiate_spw(int sockfd, const unsigned char *session_key)
+{
+    struct aes_message am;
+    struct msg_frame msg_frame;
+    struct pap pap;
+    unsigned char *tmp;
+    int error;
+
+    /* Create a PAP and encrypt it */
+    pap.spw = 0x8000;
+    pap.code = 0;
+
+    while (1) {
+        if ((error = send_frame(sockfd, &pap, sizeof(pap), session_key)) < 0) {
+            return error;
+        }
+
+        /* Receive the PAP the server replies with */
+        if ((error = recv_frame(sockfd, sizeof(pap), session_key, &pap)) < 0) {
+            return error;
+        }
+
+        /*
+         * If the server echos our PAP with code 0 then it has
+         * applied our session parameters! However, there is
+         * a chance arbitration will be needed and we need
+         * to look out for that too...
+         */
+        if (pap.code == 0) {
+            printf("** Negotiation success\n");
+            break;
+        }
+
+        printf("** Arbitration needed, server says: %s\n", pap_codestr[pap.code]);
+        printf("** Server proposes SPW of 0x%0X, accepting\n", pap.spw);
+        pap.spw |= PAP_SPW_QSR;
+        pap.code = 0;
+    }
+
+    return 0;
+}
+
+static void
+recv_motd(int sockfd, const unsigned char *session_key)
+{
+    char buf[4096];
+    int len;
+
+    /* Receive the PAP the server replies with */
+    if ((len = recv_frame(sockfd, sizeof(buf), session_key, buf)) < 0) {
+        printf("Failed to recv MOTD...\n");
+        return;
+    }
+
+    buf[len] = '\0';
+    printf("%s\n", buf);
+}
+
+static int
 request_session(void)
 {
     struct sockaddr_in addr;
     struct session_request stp_sq;
     struct x25519_keypair keypair;
+    unsigned char serv_pubkey[32];
+    unsigned char *session_key;
     int error, sockfd;
 
     addr.sin_family = AF_INET;
@@ -95,7 +165,42 @@ request_session(void)
     log_pubkey(keypair.pubkey);
 
     printf("Sending session request...\n");
-    send(sockfd, &stp_sq, sizeof(stp_sq), 0);
+    error = send(sockfd, &stp_sq, sizeof(stp_sq), 0);
+    if (error < 0) {
+        perror("Failed to send session request");
+        close(sockfd);
+        return error;
+    }
+
+    error = recv(sockfd, serv_pubkey, sizeof(serv_pubkey), 0);
+    if (error < 0) {
+        perror("Failed to get public key from peer\n");
+        close(sockfd);
+        return error;
+    }
+
+    if (error == 0) {
+        printf("Connection closed by peer\n");
+        close(sockfd);
+        return 0;
+    }
+
+    printf("Got public key from server\n");
+    log_pubkey(serv_pubkey);
+
+    printf("Deriving session key...\n");
+    gen_session_key(keypair.privkey, serv_pubkey, &session_key);
+
+    /* Send server SPW bits */
+    if ((error = negotiate_spw(sockfd, session_key)) < 0) {
+        printf("Session Parameter Negotiation failed\n");
+        free_session_key(session_key);
+        close(sockfd);
+        return error;
+    }
+
+    recv_motd(sockfd, session_key);
+    free_session_key(session_key);
     close(sockfd);
     return 0;
 }
diff --git a/lib/include/net/param.h b/lib/include/net/param.h
new file mode 100644
index 0000000..ba2a0a2
--- /dev/null
+++ b/lib/include/net/param.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the name of Hyra 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.
+ */
+
+#ifndef NET_PARAM_H_
+#define NET_PARAM_H_
+
+#include <stdint.h>
+#include <defs.h>
+
+/*
+ * The Parameter Arbitration Packet which is crucial
+ * for Session Parameter Negotiation and Arbitration.
+ */
+struct pap {
+    uint16_t spw;   /* Session parameter word */
+    uint8_t code;   /* Specific code for packet */
+};
+
+#endif  /* NET_PARAM_H_ */
diff --git a/ostp.d/include/net/auth.h b/ostp.d/include/net/auth.h
index 752bfe2..76567c3 100644
--- a/ostp.d/include/net/auth.h
+++ b/ostp.d/include/net/auth.h
@@ -33,5 +33,6 @@
 #include <net/stpsession.h>
 
 int handle_srq(int client_fd, struct session_request *srq);
+int negotiate_spw(int client_fd, unsigned char *session_key);
 
 #endif  /* NET_AUTH_H_ */
diff --git a/ostp.d/net/otd_auth.c b/ostp.d/net/otd_auth.c
index 3511e0c..6e757ae 100644
--- a/ostp.d/net/otd_auth.c
+++ b/ostp.d/net/otd_auth.c
@@ -27,9 +27,12 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <arpa/inet.h>
 #include <net/auth.h>
+#include <net/param.h>
 #include <net/stpsession.h>
 #include <crypto/ecdh.h>
+#include <otconfig.h>
 #include <stdio.h>
 
 #define KEY_BYTE_WIDTH 32
@@ -47,6 +50,17 @@ log_pubkey(uint8_t pubkey[KEY_BYTE_WIDTH])
     printf("\n");
 }
 
+static void
+send_motd(int client_fd, const unsigned char *session_key)
+{
+    char motd[] = MOTD;
+
+    printf("Sending MOTD...\n");
+    if (send_frame(client_fd, motd, sizeof(motd), session_key) < 0) {
+        printf("Failed to session MOTD\n");
+    }
+}
+
 /*
  * Verify the session request packet and handle
  * the rest.
@@ -58,6 +72,8 @@ int
 handle_srq(int client_fd, struct session_request *srq)
 {
     struct x25519_keypair keypair;
+    unsigned char *session_key;
+    int error;
 
     printf("Got public key from peer: \n");
     log_pubkey(srq->pubkey);
@@ -68,5 +84,26 @@ handle_srq(int client_fd, struct session_request *srq)
         return -1;
     }
 
+    /* Send back our our public key */
+    error = send(client_fd, keypair.pubkey, keypair.pubkey_len, 0);
+    if (error < 0) {
+        perror("Failed to send public key");
+        return error;
+    }
+
+    printf("Deriving session key...\n");
+    error = gen_session_key(keypair.privkey, srq->pubkey, &session_key);
+    if (error < 0) {
+        return error;
+    }
+
+    /* Handle any requested session parameters */
+    if ((error = negotiate_spw(client_fd, session_key)) < 0) {
+        free_session_key(session_key);
+        return error;
+    }
+
+    send_motd(client_fd, session_key);
+    free_session_key(session_key);
     return 0;
 }
diff --git a/ostp.d/net/otd_param.c b/ostp.d/net/otd_param.c
new file mode 100644
index 0000000..fe33bd8
--- /dev/null
+++ b/ostp.d/net/otd_param.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. 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.
+ * 3. Neither the name of Hyra 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 <net/stpsession.h>
+#include <net/param.h>
+#include <crypto/aes.h>
+#include <otconfig.h>
+#include <defs.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+static int
+handle_pap(int client_fd, const struct pap *pap, const unsigned char *session_key)
+{
+    int error = 0;
+    uint8_t attempts = 0;
+    struct pap tmp_pap = *pap;
+    const size_t LEN = sizeof(struct pap);
+
+    /* TODO: Support more SPW bits */
+    while (1) {
+        /* Quick session request, jump right in! */
+        if (ISSET(tmp_pap.spw, PAP_SPW_QSR)) {
+            printf("Got QSR, starting session...\n");
+            send_frame(client_fd, &tmp_pap, LEN, session_key);
+            return 0;
+        }
+
+        /* We have exhausted our attempts */
+        if (attempts >= ARBITRATION_MAX) {
+            printf("Too many arbitration attempts, bailing!\n");
+            return -1;
+        }
+
+        printf("Got bad SPW from client\n");
+        printf("Attempting arbitration...\n");
+
+        tmp_pap.spw = 0x0;
+        tmp_pap.code = PAP_BAD_SPW;
+
+        /* Send in PAP and wait for response */
+        if ((error = send_frame(client_fd, &tmp_pap, LEN, session_key)) < 0) {
+            printf("Failed to send PAP frame\n");
+            return -1;
+        }
+        if ((error = recv_frame(client_fd, LEN, session_key, &tmp_pap)) < 0) {
+            printf("Failed to recv PAP frame\n");
+            return error;
+        }
+
+        ++attempts;
+    }
+
+    return 0;
+}
+
+int
+negotiate_spw(int client_fd, unsigned char *session_key)
+{
+    const size_t LEN = sizeof(struct pap);
+    struct pap pap;
+    int error;
+
+    /* Get PAP from the network */
+    if ((error = recv_frame(client_fd, LEN, session_key, &pap)) < 0) {
+        return error;
+    }
+
+    return handle_pap(client_fd, &pap, session_key);
+}