From 9f0149df7f6da242bfef3505dabbc8a73c97dcba Mon Sep 17 00:00:00 2001
From: Nate Straz <nstraz@redhat.com>
Date: Thu, 8 Jun 2006 22:28:28 +0000
Subject: Add some checking to see if we get responses from someone we
 shouldn't be.

---
 btime.c | 36 ++++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

(limited to 'btime.c')

diff --git a/btime.c b/btime.c
index f22c08b..bb0857e 100644
--- a/btime.c
+++ b/btime.c
@@ -12,6 +12,7 @@
 
 #include "btime_int.h"
 
+static int same_addr(struct sockaddr_in *a, struct sockaddr_in *b);
 /*
  * btime --
  * 
@@ -29,7 +30,9 @@ btime(const char *host)
 	char msg[BTIME_MSGLEN];
 	struct sockaddr_in serv_addr;
 	struct sockaddr_in my_addr;
+	struct sockaddr_in resp_addr;
 	int serv_addr_len;
+	int resp_addr_len;
 	struct hostent *hostent;
 	in_addr_t inaddr;
 	unsigned int btime;
@@ -83,17 +86,26 @@ btime(const char *host)
 	}
 	
 
+	memset(&resp_addr, 0, sizeof resp_addr);
 	memset(msg, 0, BTIME_MSGLEN);
 	for (retry = 0; retry < MAX_RETRY; retry++) {
-		serv_addr_len = sizeof serv_addr;
+		resp_addr_len = sizeof resp_addr;
 		if ((nbytes = recvfrom(sd, &msg, BTIME_MSGLEN, MSG_DONTWAIT, 
-	         (struct sockaddr *)&serv_addr, &serv_addr_len)) < 0) {
+	         (struct sockaddr *)&resp_addr, &resp_addr_len)) < 0) {
 			if (errno == EAGAIN) {
 				usleep(retry * 100);
 			} else {
 				/* Non EAGAIN error... */
 				break;
 			}
+		} else if (!same_addr(&serv_addr, &resp_addr)) {
+			char *rstr = strdup(inet_ntoa(resp_addr.sin_addr));
+			char *sstr = strdup(inet_ntoa(serv_addr.sin_addr));
+			fprintf(stderr, "Got response from %s instead of %s\n",
+					rstr, sstr);
+			free(rstr);
+			free(sstr);
+			continue;
 		} else {
 			break;
 		}
@@ -109,3 +121,23 @@ btime(const char *host)
 
 	return btime;
 }
+
+/* same_addr
+ *
+ * 	Compare to struct sockaddr_in's
+ *
+ * Returns:
+ * 	1 if the addresses match
+ * 	0 if the addresses are different
+ */
+static int
+same_addr(struct sockaddr_in *a, struct sockaddr_in *b)
+{
+	if (a->sin_family != b->sin_family) {
+		return 0;
+	} else if (a->sin_addr.s_addr != b->sin_addr.s_addr) {
+		return 0;
+	} else {
+		return 1;
+	}
+}
-- 
cgit