scan: implement auto-reconnect

MultiCAN/src/drivers/scan/ellsi.c

@@ -186,6 +186,7 @@ struct ellsi_state {
     unsigned            unread; /* number of as yet unread telegrams in packet */
     int                 sock;   /* socket to communicate over */
     struct sockaddr_in  addr;   /* socket address info */
+    int                 baudrate;
 };
 
 static ssize_t ellsi_write(void *pvt, const struct can_frame *frame) {
@@ -297,7 +298,11 @@ static int ellsi_check(int sock) {
     memset(&ack, 0, sizeof(ack));
     r = recv(sock, &ack, sizeof(ack), MSG_WAITALL);
     if (r < 0) {
-        fprintf(stderr, "ellsi_check: recv failed\n"); return r;
+        if (errno != EAGAIN && errno != EWOULDBLOCK) {
+            errbuf_t buf;
+            fprintf(stderr, "ellsi_check: recv failed (%s)\n", ERRNO_STR(buf));
+        }
+        return r;
     }
     debug("ellsi_check: got back magic %#x cmd %#x subcmd %#x payloadLen %d\n",
         ntohl(ack.header.magic),
@@ -419,10 +424,54 @@ static int ellsi_add_can_ids(ellsi_state_t *state) {
     return ellsi_check(state->sock);
 }
 
+static int ellsi_connect(void *pvt) {
+    errbuf_t buf;
+    ellsi_state_t *state = (ellsi_state_t *)pvt;
+    struct timeval tmo = { 5, 0 };
+
+    /* connect socket */
+    if (connect(state->sock, (struct sockaddr *)&state->addr, sizeof(struct sockaddr_in)) < 0) {
+        fprintf(stderr, "ellsi_connect: error in socket connect (%s)\n", ERRNO_STR(buf));
+        return -1;
+    }
+    /* set recv timout for during connect */
+    if (setsockopt(state->sock, SOL_SOCKET, SO_RCVTIMEO, &tmo, sizeof(tmo)) < 0) {
+        fprintf(stderr, "ellsi_connect: error setting socket option SO_RCVTIMEO (%s)\n",
+            ERRNO_STR(buf));
+        return -1;
+    }
+    /* initialize protocol */
+    if (ellsi_register(state)) {
+        return -1;
+    }
+    /* configure baudrate */
+    if (ellsi_set_baudrate(state, state->baudrate)) {
+        return -1;
+    }
+    /* enable all CAN ids */
+    if (ellsi_add_can_ids(state)) {
+        return -1;
+    }
+    /* reset timout for recv operation to zero (default, infinite) */
+    tmo.tv_sec = 0;
+    if (setsockopt(state->sock, SOL_SOCKET, SO_RCVTIMEO, &tmo, sizeof(tmo)) < 0) {
+        fprintf(stderr, "ellsi_connect: error resetting socket option SO_RCVTIMEO (%s)\n",
+            ERRNO_STR(buf));
+        return -1;
+    }
+    return 0;
+}
+
+static scan_methods_t methods = {
+    ellsi_read,
+    ellsi_write,
+    ellsi_dump,
+    ellsi_connect
+};
+
 int ellsiConfigPort(int can_port, const char *ip_addr, int ip_port, int baudrate) {
     errbuf_t buf;
     ellsi_state_t *state = new(ellsi_state_t);
-    scan_methods_t *methods;
 
     if (!state) {
         fprintf(stderr, "ellsiConfigPort: out of memory\n");
@@ -442,41 +491,8 @@ int ellsiConfigPort(int can_port, const char *ip_addr, int ip_port, int baudrate
         free(state);
         return -1;
     }
-    /* success, connect socket */
-    if (connect(state->sock, (struct sockaddr *)&state->addr, sizeof(struct sockaddr_in)) < 0) {
-        fprintf(stderr, "ellsiConfigPort: error in socket connect (%s)\n", ERRNO_STR(buf));
-        free(state);
-        return -1;
-    }
-    /* success, allocate methods */
-    methods = new(scan_methods_t);
-    if (!methods) {
-        fprintf(stderr, "ellsiConfigPort: out of memory\n");
-        free(state);
-        return -1;
-    }
-    /* success, fill methods struct */
-    methods->write = ellsi_write;
-    methods->read = ellsi_read;
-    methods->dump = ellsi_dump;
-    /* initialize protocol */
-    if (ellsi_register(state)) {
-        fprintf(stderr, "ellsiConfigPort: error in ellsi_register\n");
-        free(state);
-        return -1;
-    }
-    /* configure baudrate */
-    if (ellsi_set_baudrate(state, baudrate)) {
-        fprintf(stderr, "ellsiConfigPort: error in ellsi_set_baudrate\n");
-        free(state);
-        return -1;
-    }
-    /* enable all CAN ids */
-    if (ellsi_add_can_ids(state)) {
-        fprintf(stderr, "ellsiConfigPort: error in ellsi_add_can_ids\n");
-        free(state);
-        return -1;
-    }
+    /* success, store driver specific configuration */
+    state->baudrate = baudrate;
     /* install driver and initialize sci port */
-    return scan_config_port(can_port, state, methods);
+    return scan_config_port(can_port, state, &methods);
 }

MultiCAN/src/drivers/scan/scan.c

@@ -481,7 +481,6 @@ int scan_config_port(
                 tid = epicsThreadCreate(name, epicsThreadPriorityMax-1,
                     epicsThreadGetStackSize(epicsThreadStackSmall), sci_listen, sci_port);
                 if (tid) {
-                    /* done */
                     res = 0;
                 } else {
                     fprintf(stderr, "scan_config_port: thread create failed (%s)\n",
@@ -512,7 +511,13 @@ static void sci_listen(void *parg) {
     errbuf_t buf;
     struct sci_port *port = (struct sci_port *)parg;
 
-    port->connected = 1;
+    /* initial connection attempt */
+    if (port->methods->connect) {
+        /* try to reconnect */
+        port->connected = (port->methods->connect(port->driver_pvt) == 0);
+    } else {
+        port->connected = 1;
+    }
 
     while (1) {
         if (port->connected) {
@@ -567,8 +572,15 @@ static void sci_listen(void *parg) {
             }
         } else {
             epicsThreadSleep(5.0);
-            /* TODO try to reconnect */
-            port->connected = 1;
+            if (port->methods->connect) {
+                /* try to reconnect */
+                port->connected = (port->methods->connect(port->driver_pvt) == 0);
+                if (port->connected) {
+                    errlogSevPrintf(errlogInfo,
+                        "sci_listen: successfully re-connected port %d\n",
+                        port->port_num);
+                }
+            }
         }
     }
 }

MultiCAN/src/drivers/scan/scan_driver.h

@@ -4,6 +4,9 @@
  * The driver should implement a configuration/initialization call.
  * This should create a socket, allocate struct scan_io_methods,
  * fill in appropriate methods, and then call scan_config_port.
+ * This in turn will call connect method, when port has been set up.
+ * The connect method is also called when connection has been lost
+ * and we should re-connect.
  * It can also remember private data in the driver_pvt parameter
  * passed to scan_config_port.
  *
@@ -21,6 +24,7 @@
 typedef ssize_t write_t(void *pvt, const struct can_frame *frame);
 typedef ssize_t read_t(void *pvt, struct can_frame *frame);
 typedef void dump_t(void *pvt);
+typedef int connect_t(void *pvt);
 
 typedef struct scan_methods scan_methods_t;
 
@@ -28,12 +32,13 @@ struct scan_methods {
     read_t *read;       /* read a can frame */
     write_t *write;     /* write a can frame to a socket */
     dump_t *dump;       /* dump private driver info to stdout */
+    connect_t *connect; /* driver specific connect actions for this port */
 };
 
 /*
  * Parameter 'methods' must be allocated by the caller and fully
  * initialized. NULL is admissible for 'driver_pvt' but not for
- * the methods.
+ * the methods, except 'connect', which may be NULL.
  * It is an error if the port is already configured.
  */
 extern int scan_config_port(