Better error messages

diff --git a/tftp.c b/tftp.c
index a87f426c66b4a844f28fd9aadcbee26c85ec838d..a9aac18181009395d7d0081b232c5261f2fb4350 100644 (file)
--- a/tftp.c
+++ b/tftp.c
@@ -17,13 +17,13 @@
  *
  */
 
-#define _BSD_SOURCE
 #include <string.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <ctype.h>
 #include "nmrpd.h"
 
 #define TFTP_PKT_SIZE 516
@@ -130,12 +130,18 @@ static ssize_t tftp_recvfrom(int sock, char *pkt, struct sockaddr_in *src)
        if (opcode == ERR) {
                fprintf(stderr, "Error (%d): %.511s\n", pkt_num(pkt + 2), pkt + 4);
                return -1;
-       } else if (!opcode || opcode > ERR) {
-               /* The EX2700 I've tested this on sends a raw TFTP packet with no
-                * opcode, and an error message starting at offset 0.
+       } else if (isprint(pkt[0])) {
+               /* In case of a firmware checksum error, the EX2700 I've tested this
+                * on sends a raw UDP packet containing just an error message starting
+                * at offset 0. The limit of 32 chars is arbitrary.
                 */
                fprintf(stderr, "Error: %.32s\n", pkt);
                return -3;
+       } else {
+               fprintf(stderr, "Received invalid packet: ");
+               pkt_print(pkt, stderr);
+               fprintf(stderr, ".\n");
+               return -2;
        }
 
        return len;
@@ -162,8 +168,9 @@ static ssize_t tftp_sendto(int sock, char *pkt, size_t len,
                        len = 4 + strlen(pkt + 4);
                        break;
                default:
-                       fprintf(stderr, "Error: Invalid packet ");
+                       fprintf(stderr, "Attempted to send invalid packet ");
                        pkt_print(pkt, stderr);
+                       fprintf(stderr, "; this is a bug!\n");
                        return -1;
        }