Support for ICMP Echo protocol

diff --git a/common/icmp.c b/common/icmp.c
new file mode 100644 (file)
index 0000000..3633a71
--- /dev/null
+++ b/common/icmp.c
@@ -0,0 +1,159 @@
+/* dhcp.c
+
+   ICMP Protocol engine - for sending out pings and receiving
+   responses. */
+
+/*
+ * Copyright (c) 1997 The Internet Software Consortium.
+ * 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. Neither the name of The Internet Software Consortium nor the names
+ *    of its contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
+ * CONTRIBUTORS ``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 INTERNET SOFTWARE CONSORTIUM OR
+ * CONTRIBUTORS 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 software has been written for the Internet Software Consortium
+ * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
+ * Enterprises.  To learn more about the Internet Software Consortium,
+ * see ``http://www.vix.com/isc''.  To learn more about Vixie
+ * Enterprises, see ``http://www.vix.com''.
+ */
+
+static struct protocol icmp_protocol;
+
+/* Initialize the ICMP protocol. */
+
+void icmp_startup (routep, handler)
+       int routep;
+       unsigned void (*handler) PROTO ((struct iaddr, u_int8_t *, int));
+{
+       struct protoent *proto;
+       int protocol = 1;
+       struct sockaddr_in from;
+
+       /* Only initialize icmp once. */
+       if (icmp_protocol.initialized)
+               error ("attempted to reinitialize icmp protocol");
+       icmp_protocol.initialized = 1;
+
+       /* Get the protocol number (should be 1). */
+       proto = getprotobyname ("icmp");
+       if (proto)
+               protocol = proto -> p_proto;
+
+       /* Get a raw socket for the ICMP protocol. */
+       icmp_protocol.fd = socket (AF_INET, SOCK_RAW, protocol);
+       if (!icmp_protocol.fd)
+               error ("unable to create icmp socket: %m");
+
+       if (setsockopt (icmp_protocol.fd, SOL_SOCKET, SO_DONTROUTE,
+                       (char *)&routep, sizeof routep))
+               error ("Can't set SO_DONTROUTE on ICMP socket: %m");
+
+       icmp_protocol.handler = icmp_echoreply;
+       icmp_protocol.local = handler;
+       add_protocol (&icmp_protocol);
+}
+
+int icmp_echorequest (addr)
+       struct iaddr *addr;
+{
+       struct sockaddr_in to;
+       struct icmp icmp;
+       int status;
+
+       if (!icmp_protocol.initialized)
+               error ("attempt to use ICMP protocol before initialization.");
+
+#ifdef HAVE_SA_LEN
+       to.sin_len = sizeof to;
+#endif
+       to.sin_family = AF_INET;
+       to.sin_port = 0; /* unused. */
+       memcpy (&to.sin_addr, addr -> iabuf, sizeof to.sin_addr); /* XXX */
+
+       icmp.icmp_type = ICMP_ECHO;
+       icmp.icmp_code = 0;
+       icmp.icmp_cksum = 0;
+       icmp.icmp_seq = 0;
+#ifdef PTRSIZE_64BIT
+       icmp.icmp_id = (((u_int32_t)addr) ^
+                       (u_int32_t)(((u_int64_t)addr) >> 32));
+#else
+       icmp.icmp_id = (u_int32_t)addr;
+#endif
+
+       icmp.icmp_cksum = wrapsum (checksum ((unsigned char *)&icmp,
+                                            sizeof icmp, 0));
+
+       /* Send the ICMP packet... */
+       status = sendto (icmp_protocol.fd, &icmp, sizeof icmp, 0,
+                        (struct sockaddr *)&to, sizeof to);
+       if (status < 0)
+               warn ("icmp_echorequest: %m");
+
+       if (status != sizeof icmp)
+               return 0;
+       return 1;
+}
+
+void icmp_echoreply (protocol)
+       struct protocol *protocol;
+{
+       struct icmp *icfrom;
+       struct sockaddr_in from;
+       unsigned char icbuf [1500];
+       int status;
+       int len;
+       struct iaddr ia;
+       unsigned void (*handler) PROTO ((struct iaddr, u_int8_t *, int));
+
+       len = sizeof from;
+       icbuf = recvfrom (protocol -> fd, icbuf, sizeof icbuf, 0,
+                         (struct sockaddr *)&from, &len);
+       if (icbuf < 0) {
+               warn ("icmp_echoreply: %m");
+               return;
+       }
+       if (icbuf < sizeof *icfrom) {
+               warn ("icmp_echoreply: short packet");
+               return;
+       }
+
+       icfrom = (struct icmp *)icbuf;
+
+       /* Silently discard ICMP packets that aren't echoreplies. */
+       if (icfrom -> icmp_type != ICMP_ECHOREPLY)
+               return;
+
+       /* If we were given a second-stage handler, call it. */
+       if (protocol -> local) {
+               handler = protocol -> local;
+               memcpy (ia.iaddr, &from.sin_addr, sizeof from.sin_addr);
+               ia.len = sizeof from.sin_addr;
+
+               (*handler) (ia, icbuf, result);
+       }
+}