SSL socket snippet, server checks client's certificates

SSL_Socket_snippet/client.c

@@ -0,0 +1,79 @@
+/*
+ * This file is part of the sslsosk project.
+ * Copyright 2023 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <usefull_macros.h>
+
+#include "client.h"
+
+static int SSL_nbread(SSL *ssl, char *buf, int bufsz){
+    struct pollfd fds = {0};
+    int fd = SSL_get_fd(ssl);
+    fds.fd = fd;
+    fds.events = POLLIN;
+    if(poll(&fds, 1, 1) < 0){ // wait no more than 1ms
+        LOGWARN("SSL_nbread(): poll() failed");
+        WARNX("poll()");
+        return 0;
+    }
+    if(fds.revents == POLLIN){
+//        DBG("Got info in fd #%d", fd);
+        int l = read_string(ssl, buf, bufsz);
+//        DBG("read %d bytes", l);
+        return l;
+    }
+    return 0;
+}
+
+void clientproc(SSL_CTX *ctx, int fd){
+    FNAME();
+    SSL *ssl;
+    char buf[1024];
+    char acClientRequest[1024] = {0};
+    int bytes;
+    ssl = SSL_new(ctx);
+    SSL_set_fd(ssl, fd);
+    int c = SSL_connect(ssl);
+    if(c < 0){
+        LOGERR("SSL_connect()");
+        ERRX("SSL_connect() error: %d", SSL_get_error(ssl, c));
+    }
+    int enable = 1;
+    if(ioctl(fd, FIONBIO, (void *)&enable) < 0){
+        LOGERR("Can't make socket nonblocking");
+        ERRX("ioctl()");
+    }
+    double t0 = dtime();
+    int N = 0;
+    while(1){
+        if(dtime() - t0 > 3.){
+           // DBG("Sent test message");
+            sprintf(acClientRequest, "Test connection #%d\n", ++N);
+            SSL_write(ssl, acClientRequest, strlen(acClientRequest));
+            t0 = dtime();
+        }
+        bytes = SSL_nbread(ssl, buf, sizeof(buf));
+        if(bytes > 0){
+            buf[bytes] = 0;
+            printf("Received: \"%s\"\n", buf);
+        }else if(bytes < 0){
+            LOGWARN("Server disconnected or other error");
+            ERRX("Disconnected");
+        }
+    }
+    SSL_free(ssl);
+}