From 951f1300a0a789f46f8b2660ad68318f3843a5ba Mon Sep 17 00:00:00 2001
From: Kaspar Schleiser <kaspar@schleiser.de>
Date: Wed, 3 Feb 2016 16:04:32 +0100
Subject: [PATCH] sys: shell: ping6: require device parameter for link-local
 addresses

---
 sys/shell/commands/sc_icmpv6_echo.c | 49 +++++++++++++++++++++++++++--
 1 file changed, 47 insertions(+), 2 deletions(-)

diff --git a/sys/shell/commands/sc_icmpv6_echo.c b/sys/shell/commands/sc_icmpv6_echo.c
index 5a61a2df97..c418e06396 100644
--- a/sys/shell/commands/sc_icmpv6_echo.c
+++ b/sys/shell/commands/sc_icmpv6_echo.c
@@ -38,9 +38,10 @@ static char ipv6_str[IPV6_ADDR_MAX_STR_LEN];
 
 static void usage(char **argv)
 {
-    printf("%s [<count>] <ipv6 addr> [<payload_len>] [<delay in ms>] [<stats interval>]\n", argv[0]);
+    printf("%s [<count>] <ipv6 addr>[%%<interface>] [<payload_len>] [<delay in ms>] [<stats interval>]\n", argv[0]);
     puts("defaults:");
     puts("    count = 3");
+    puts("    interface = first interface if only one present, only needed for link-local addresses");
     puts("    payload_len = 4");
     puts("    delay = 1000");
     puts("    stats interval = count");
@@ -148,6 +149,7 @@ int _icmpv6_ping(int argc, char **argv)
     uint32_t delay = 1 * SEC_IN_MS;
     char *addr_str;
     ipv6_addr_t addr;
+    kernel_pid_t src_iface;
     msg_t msg;
     gnrc_netreg_entry_t *ipv6_entry, my_entry = { NULL, ICMPV6_ECHO_REP,
                                                   thread_getpid() };
@@ -170,7 +172,6 @@ int _icmpv6_ping(int argc, char **argv)
     stat_interval = count;
 
     addr_str = argv[1 + param_offset];
-
     if (argc > (2 + param_offset)) {
         payload_len = atoi(argv[2 + param_offset]);
     }
@@ -186,11 +187,43 @@ int _icmpv6_ping(int argc, char **argv)
         return 1;
     }
 
+    src_iface = ipv6_addr_split_iface(addr_str);
+    if (src_iface == -1) {
+        src_iface = KERNEL_PID_UNDEF;
+    }
+
     if (ipv6_addr_from_str(&addr, addr_str) == NULL) {
         puts("error: malformed address");
         return 1;
     }
 
+    if (ipv6_addr_is_link_local(&addr) || (src_iface != KERNEL_PID_UNDEF)) {
+        kernel_pid_t ifs[GNRC_NETIF_NUMOF];
+        size_t ifnum = gnrc_netif_get(ifs);
+        if (src_iface == KERNEL_PID_UNDEF) {
+            if (ifnum == 1) {
+                src_iface = ifs[0];
+            }
+            else {
+                puts("error: link local target needs interface parameter (use \"<address>%<ifnum>\")\n");
+                return 1;
+            }
+        }
+        else {
+            int valid = 0;
+            for (size_t i = 0; i < ifnum && i < GNRC_NETIF_NUMOF; i++) {
+                if (ifs[i] == src_iface) {
+                    valid = 1;
+                    break;
+                }
+            }
+            if (!valid) {
+                printf("error: %"PRIkernel_pid" is not a valid interface.\n", src_iface);
+                return 1;
+            }
+        }
+    }
+
     if (gnrc_netreg_register(GNRC_NETTYPE_ICMPV6, &my_entry) < 0) {
         puts("error: network registry is full");
         return 1;
@@ -229,6 +262,18 @@ int _icmpv6_ping(int argc, char **argv)
             continue;
         }
 
+        if (src_iface != KERNEL_PID_UNDEF) {
+            pkt = gnrc_pktbuf_add(pkt, NULL, sizeof(gnrc_netif_hdr_t),
+                                  GNRC_NETTYPE_NETIF);
+
+            if (pkt == NULL) {
+                puts("error: packet buffer full");
+                continue;
+            }
+
+            ((gnrc_netif_hdr_t *)pkt->data)->if_pid = src_iface;
+        }
+
         start = xtimer_now();
         if (gnrc_netapi_send(ipv6_entry->pid, pkt) < 1) {
             puts("error: unable to send ICMPv6 echo request\n");