Task #14314: Add interface name/index APIs

This commit adds the following sets of interface name/index APIs:

Interface Identification APIs from RFC 3493:
  * lwip_if_nametoindex (COMPAT macro if_nametoindex)
  * lwip_if_indextoname (COMPAT macro if_indextoname)

netifapi:
  * netifapi_netif_name_to_index
  * netifapi_netif_index_to_name

netif:
  * netif_name_to_index
  * netif_index_to_name
  * netif_num_to_index
  * netif_index_to_num

src/api/if.c

@@ -0,0 +1,73 @@
+/**
+ * @file
+ * Interface Identification APIs from:
+ *              RFC 3493: Basic Socket Interface Extensions for IPv6
+ *                  Section 4: Interface Identification
+ */
+
+/*
+ * Copyright (c) 2017 Joel Cunningham <joel.cunningham@me.com>
+ * 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. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Joel Cunningham <joel.cunningham@me.com>
+ *
+ */
+#include "lwip/opt.h"
+
+#if LWIP_SOCKET
+
+#include "lwip/netifapi.h"
+
+char *
+lwip_if_indextoname(unsigned ifindex, char *ifname)
+{
+  err_t err;
+  if (ifindex > 0xff) {
+    return NULL;
+  }
+  
+  err = netifapi_netif_index_to_name((u8_t)ifindex, ifname);
+  if (!err && ifname[0] != '\0') {
+    return ifname;
+  }
+  return NULL;
+}
+
+unsigned int
+lwip_if_nametoindex(const char *ifname)
+{
+  err_t err;
+  u8_t index;
+  
+  err = netifapi_netif_name_to_index(ifname, &index);
+  if (!err) {
+    return index;
+  }
+  return 0; /* invalid index */
+}
+
+#endif /* LWIP_SOCKET */

src/api/netifapi.c

@@ -46,6 +46,8 @@
 #include "lwip/memp.h"
 #include "lwip/priv/tcpip_priv.h"
 
+#include <string.h> /* strncpy */
+
 #define NETIFAPI_VAR_REF(name)      API_VAR_REF(name)
 #define NETIFAPI_VAR_DECLARE(name)  API_VAR_DECLARE(struct netifapi_msg, name)
 #define NETIFAPI_VAR_ALLOC(name)    API_VAR_ALLOC(struct netifapi_msg, MEMP_NETIFAPI_MSG, name, ERR_MEM)
@@ -95,6 +97,37 @@ netifapi_do_netif_set_addr(struct tcpip_api_call_data *m)
 }
 #endif /* LWIP_IPV4 */
 
+/**
+* Call netif_name_to_index() inside the tcpip_thread context.
+*/
+static err_t
+netifapi_do_name_to_index(struct tcpip_api_call_data *m)
+{
+  /* cast through void* to silence alignment warnings.
+   * We know it works because the structs have been instantiated as struct netifapi_msg */
+  struct netifapi_msg *msg = (struct netifapi_msg*)(void*)m;
+
+  msg->msg.ifs.index = netif_name_to_index(msg->msg.ifs.name);
+  return ERR_OK;
+}
+
+/**
+* Call netif_index_to_name() inside the tcpip_thread context.
+*/
+static err_t
+netifapi_do_index_to_name(struct tcpip_api_call_data *m)
+{
+  /* cast through void* to silence alignment warnings.
+   * We know it works because the structs have been instantiated as struct netifapi_msg */
+  struct netifapi_msg *msg = (struct netifapi_msg*)(void*)m;
+
+  if (!netif_index_to_name(msg->msg.ifs.index, msg->msg.ifs.name)) {
+    /* return failure via empty name */
+    msg->msg.ifs.name[0] = '\0';
+  }
+  return ERR_OK;
+}
+
 /**
  * Call the "errtfunc" (or the "voidfunc" if "errtfunc" is NULL) inside the
  * tcpip_thread context.
@@ -218,4 +251,66 @@ netifapi_netif_common(struct netif *netif, netifapi_void_fn voidfunc,
   return err;
 }
 
+/**
+* @ingroup netifapi_netif
+* Call netif_name_to_index() in a thread-safe way by running that function inside the
+* tcpip_thread context.
+*
+* @param name the interface name of the netif
+* @param index output index of the found netif
+*/
+err_t
+netifapi_netif_name_to_index(const char *name, u8_t *index)
+{
+  err_t err;
+  NETIFAPI_VAR_DECLARE(msg);
+  NETIFAPI_VAR_ALLOC(msg);
+
+  *index = 0;
+
+#if LWIP_MPU_COMPATIBLE
+  strncpy(NETIFAPI_VAR_REF(msg).msg.ifs.name, name, IF_NAMESIZE - 1);
+  NETIFAPI_VAR_REF(msg).msg.ifs.name[IF_NAMESIZE - 1] = '\0';
+#else
+  NETIFAPI_VAR_REF(msg).msg.ifs.name = (char *)name;
+#endif /* LWIP_MPU_COMPATIBLE */
+  err = tcpip_api_call(netifapi_do_name_to_index, &API_VAR_REF(msg).call);
+  if (!err) {
+    *index = NETIFAPI_VAR_REF(msg).msg.ifs.index;
+  }
+  NETIFAPI_VAR_FREE(msg);
+  return err;
+}
+
+/**
+* @ingroup netifapi_netif
+* Call netif_index_to_name() in a thread-safe way by running that function inside the
+* tcpip_thread context.
+*
+* @param index the interface index of the netif
+* @param name output name of the found netif, empty '\0' string if netif not found.
+*             name should be of at least IF_NAMESIZE bytes
+*/
+err_t
+netifapi_netif_index_to_name(u8_t index, char *name)
+{
+  err_t err;
+  NETIFAPI_VAR_DECLARE(msg);
+  NETIFAPI_VAR_ALLOC(msg);
+
+  NETIFAPI_VAR_REF(msg).msg.ifs.index = index;
+#if !LWIP_MPU_COMPATIBLE
+  NETIFAPI_VAR_REF(msg).msg.ifs.name = name;
+#endif /* LWIP_MPU_COMPATIBLE */
+  err = tcpip_api_call(netifapi_do_index_to_name, &API_VAR_REF(msg).call);
+#if LWIP_MPU_COMPATIBLE
+  if (!err) {
+    strncpy(name, NETIFAPI_VAR_REF(msg).msg.ifs.name, IF_NAMESIZE - 1);
+    name[IF_NAMESIZE - 1] = '\0';
+  }
+#endif /* LWIP_MPU_COMPATIBLE */
+  NETIFAPI_VAR_FREE(msg);
+  return err;
+}
+
 #endif /* LWIP_NETIF_API */