add serialsock

Socket_CAN/cansock.c

@@ -0,0 +1,76 @@
+/*
+ * This file is part of the SocketCAN project.
+ * Copyright 2021 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/>.
+ */
+
+
+int readCAN(int sock, struct can_frame *frame){
+    fd_set fds;
+    struct timeval timeout;
+    timeout.tv_sec = 0;
+    timeout.tv_usec = 1000; // wait not more than 1millisecond
+    FD_ZERO(&fds);
+    FD_SET(sock, &fds);
+    do{
+        int rc = select(sock+1, &fds, NULL, NULL, &timeout);
+        if(rc < 0){
+            if(errno != EINTR){
+                WARN("select()");
+                return 0;
+            }
+            continue;
+        }
+        break;
+    }while(1);
+    if(FD_ISSET(sock, &fds)){
+        return read(sock, frame, sizeof(struct can_frame));
+    }
+    return 0;
+}
+
+
+
+int sock = socket(PF_CAN, SOCK_RAW, CAN_RAW);
+if(sock < 0) ERR("Can't create socket");
+struct sockaddr_can addr;
+struct ifreq ifr;
+strcpy(ifr.ifr_name, "can0");
+if(ioctl(sock, SIOCGIFINDEX, &ifr) < 0) ERR("ioctl()");
+addr.can_family = AF_CAN;
+addr.can_ifindex = ifr.ifr_ifindex;
+if(bind(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) ERR("bind()");
+int nbytes = 0;
+struct can_frame frame = {0};
+double dt = dtime();
+do{
+    nbytes = readCAN(sock, &frame);
+    if(nbytes < 0) ERR("can raw socket read");
+}while(nbytes == 0 && dtime() - dt < 10.);
+printf("got frame len=%d id=%d", frame.can_dlc, frame.can_id);
+if(frame.can_dlc) printf(", data: ");
+for(int i = 0; i < frame.can_dlc; ++i)
+    printf("0x%02x ", frame.data[i]);
+printf("\n");
+frame.can_dlc = 6;
+frame.can_id = 0xaa;
+const uint8_t d[] = {1, 2, 3, 4, 5, 6, 0, 0};
+memcpy(&frame.data, d, 8);
+int n = write(sock, &frame, sizeof(struct can_frame));
+if(sizeof(struct can_frame) != n){
+    printf("n=%d\n", n);
+    WARN("write()");
+}
+close(sock);