ping: implement -I option

1 files changed, 51 insertions, 10 deletions

diff --git a/networking/ping.c b/networking/ping.c
index 967a3e378..18fb926ad 100644
--- a/networking/ping.c
+++ b/networking/ping.c
@@ -155,6 +155,7 @@ int ping_main(int argc, char **argv)
 #else /* ! CONFIG_FEATURE_FANCY_PING */
 /* full(er) version */
 static struct sockaddr_in pingaddr;
+static struct sockaddr_in sourceaddr;
 static int pingsock = -1;
 static int datalen; /* intentionally uninitialized to work around gcc bug */
 
@@ -264,16 +265,15 @@ static void unpack(char *buf, int sz, struct sockaddr_in *from)
 
         gettimeofday(&tv, NULL);
 
-        /* check IP header */
-        iphdr = (struct iphdr *) buf;
-        hlen = iphdr->ihl << 2;
         /* discard if too short */
         if (sz < (datalen + ICMP_MINLEN))
                 return;
 
+        /* check IP header */
+        iphdr = (struct iphdr *) buf;
+        hlen = iphdr->ihl << 2;
         sz -= hlen;
         icmppkt = (struct icmp *) (buf + hlen);
-
         if (icmppkt->icmp_id != myid)
                 return;                         /* not our ping */
 
@@ -329,12 +329,17 @@ static void ping(const char *host)
 
         pingsock = create_icmp_socket();
 
+        if (sourceaddr.sin_addr.s_addr) {
+                if (bind(pingsock, (struct sockaddr*)&sourceaddr, sizeof(sourceaddr)) == -1)
+                        bb_error_msg_and_die("could not bind to address");
+        }
+
         memset(&pingaddr, 0, sizeof(struct sockaddr_in));
 
         pingaddr.sin_family = AF_INET;
         hostent = xgethostbyname(host);
         if (hostent->h_addrtype != AF_INET)
-                bb_error_msg_and_die("unknown address type; only AF_INET is currently supported.");
+                bb_error_msg_and_die("unknown address type; only AF_INET is currently supported");
 
         memcpy(&pingaddr.sin_addr, hostent->h_addr, sizeof(pingaddr.sin_addr));
 
@@ -348,10 +353,14 @@ static void ping(const char *host)
         setsockopt(pingsock, SOL_SOCKET, SO_RCVBUF, (char *) &sockopt,
                            sizeof(sockopt));
 
-        printf("PING %s (%s): %d data bytes\n",
-                   hostent->h_name,
-                   inet_ntoa(*(struct in_addr *) &pingaddr.sin_addr.s_addr),
-                   datalen);
+        printf("PING %s (%s)",
+                        hostent->h_name,
+                        inet_ntoa(*(struct in_addr *) &pingaddr.sin_addr.s_addr));
+        if (sourceaddr.sin_addr.s_addr) {
+                printf(" from %s",
+                        inet_ntoa(*(struct in_addr *) &sourceaddr.sin_addr.s_addr));
+        }
+        printf(": %d data bytes\n", datalen);
 
         signal(SIGINT, pingstats);
 
@@ -378,6 +387,27 @@ static void ping(const char *host)
         pingstats(0);
 }
 
+/* TODO: consolidate ether-wake.c, dnsd.c, ifupdown.c, nslookup.c
+ * versions of below thing. BTW we have far too many "%u.%u.%u.%u" too...
+*/
+static int parse_nipquad(const char *str, struct sockaddr_in* addr)
+{
+        char dummy;
+        unsigned i1, i2, i3, i4;
+        if (sscanf(str, "%u.%u.%u.%u%c",
+                           &i1, &i2, &i3, &i4, &dummy) == 4
+        && ( (i1|i2|i3|i4) <= 0xff )
+        ) {
+                uint8_t* ptr = (uint8_t*)&addr->sin_addr;
+                ptr[0] = i1;
+                ptr[1] = i2;
+                ptr[2] = i3;
+                ptr[3] = i4;
+                return 0;
+        }
+        return 1; /* error */
+}
+
 int ping_main(int argc, char **argv)
 {
         char *thisarg;
@@ -386,7 +416,6 @@ int ping_main(int argc, char **argv)
 
         argc--;
         argv++;
-        options = 0;
         /* Parse any options */
         while (argc >= 1 && **argv == '-') {
                 thisarg = *argv;
@@ -407,6 +436,18 @@ int ping_main(int argc, char **argv)
                         argv++;
                         datalen = atoi(*argv);
                         break;
+                case 'I':
+                        if (--argc <= 0)
+                                bb_show_usage();
+                        argv++;
+/* ping6 accepts iface too:
+                        if_index = if_nametoindex(*argv);
+                        if (!if_index) ...
+   make it true for ping too. TODO.
+*/
+                        if (parse_nipquad(*argv, &sourceaddr))
+                                bb_show_usage();
+                        break;
                 default:
                         bb_show_usage();
                 }