cleanup/correct telnet option printing.

diff --git a/print-telnet.c b/print-telnet.c
index 510707ace2a35abce07a37a829fde7b324c358a9..65d25fd3d7ce8de040b5fe6208cac8d4524272ea 100644 (file)
--- a/print-telnet.c
+++ b/print-telnet.c
@@ -51,7 +51,7 @@
 
 #ifndef lint
 static const char rcsid[] =
-     "@(#) $Header: /tcpdump/master/tcpdump/print-telnet.c,v 1.13 2001-06-15 07:43:13 itojun Exp $";
+     "@(#) $Header: /tcpdump/master/tcpdump/print-telnet.c,v 1.14 2001-06-25 22:49:36 itojun Exp $";
 #endif
 
 #include <sys/param.h>
@@ -77,106 +77,144 @@ static const char rcsid[] =
 # define TELCMD_FIRST SE
 #endif
 
-void
-telnet_print(register const u_char *sp, u_int length)
+/* sp points to IAB byte */
+static int
+telnet_parse(const u_char *sp, u_int length, int print)
 {
-       static char tnet[128];
-       register int i, c, x;
-       register u_char *rcp;
-       int off, first = 1;
-       u_char  *osp;
-
-       off = 0;
-       x = 0;
-       
-       while (length > 0 && *sp == IAC) {
-               osp = (u_char *) sp;
-               tnet[0] = '\0';
-               
-               c = *sp++;
-               length--;
-               switch (*sp) {
-               case IAC:                       /* <IAC><IAC>! */
-                       if (length > 1 && sp[1] == IAC) {
-                               (void)strlcpy(tnet, "IAC IAC", sizeof(tnet));
-                       } else {
-                               length = 0;
-                               continue;
-                       }
+       int i, c, x;
+       const u_char *osp, *p;
+#define PEEK(c, sp, length) \
+       do { \
+               if (length < 1) \
+                       goto trunc; \
+               c = *sp; \
+       } while (0)
+#define FETCH(c, sp, length) \
+       do { \
+               PEEK((c), (sp), (length)); \
+               sp++; \
+               length--; \
+       } while (0)
+
+       osp = sp;
+
+       FETCH(c, sp, length);
+       if (c != IAC)
+               goto trunc;
+       FETCH(c, sp, length);
+       if (c == IAC) {         /* <IAC><IAC>! */
+               if (print)
+                       printf("IAC IAC");
+               goto done;
+       }
+
+       i = c - TELCMD_FIRST;
+       if (i < 0 || i > IAC - TELCMD_FIRST) {
+               (void)printf("unknown: ff%02x\n", c);
+               goto trunc;
+       }
+
+       switch (c) {
+       case DONT:
+       case DO:
+       case WONT:
+       case WILL:
+       case SB:
+               /* DONT/DO/WONT/WILL x */
+               FETCH(x, sp, length);
+               if (x >= 0 && x < NTELOPTS) {
+                       if (print)
+                               (void)printf("%s %s", telcmds[i], telopts[x]);
+               } else {
+                       if (print)
+                               (void)printf("%s %#x", telcmds[i], x);
+               }
+               if (c != SB)
                        break;
-               default:
-                       c = *sp++;
-                       length--;
-                       if ((i = c - TELCMD_FIRST) < 0
-                           || i > IAC - TELCMD_FIRST) {
-                               (void)printf("unknown: ff%02x\n", c);
-                               return;
-                       }
-                       switch (c) {
-                       case DONT:
-                       case DO:
-                       case WONT:
-                       case WILL:
-                       case SB:
-                               x = *sp++; /* option */
-                               length--;
-                               if (x >= 0 && x < NTELOPTS) {
-                                       (void)snprintf(tnet, sizeof(tnet),
-                                           "%s %s", telcmds[i], telopts[x]);
-                               } else {
-                                       (void)snprintf(tnet, sizeof(tnet),
-                                           "%s %#x", telcmds[i], x);
-                               }
+               /* IAC SB .... IAC SE */
+               p = sp;
+               while (length > p + 1 - sp) {
+                       if (p[0] == IAC && p[1] == SE)
                                break;
-                       default:
-                               (void)snprintf(tnet, sizeof(tnet), "%s",
-                                   telcmds[i]);
+                       p++;
+               }
+               if (*p != IAC)
+                       goto trunc;
+
+               PEEK(c, sp, length);
+               if (c) {
+                       while (p > sp) {
+                               FETCH(x, sp, length);
+                               if (print)
+                                       (void)printf(" %#x", x);
                        }
-                       if (c == SB) {
-                               c = *sp++;
-                               length--;
-                               (void)strcat(tnet, c ? " SEND" : " IS '");
-                               rcp = (u_char *) sp;
-                               i = strlen(tnet);
-                               while (length > 0 && (x = *sp++) != IAC)
-                                       --length;
-                               if (x == IAC) {
-                                       if (2 < vflag
-                                           && i + 16 + sp - rcp < sizeof(tnet)) {
-                                               (void)strncpy(&tnet[i], rcp, sp - rcp);
-                                               i += (sp - rcp) - 1;
-                                               tnet[i] = '\0';
-                                       } else if (i + 8 < sizeof(tnet)) {
-                                               (void)strcat(&tnet[i], "...");
-                                       }
-                                       if (*sp++ == SE
-                                           && i + 4 < sizeof(tnet))
-                                               (void)strcat(tnet, c ? " SE" : "' SE");
-                               } else if (i + 16 < sizeof(tnet)) {
-                                       (void)strcat(tnet, " truncated!");
-                               }
+               } else {
+                       FETCH(c, sp, length);
+                       if (print)
+                               (void)printf(" IS '");
+                       while (p > sp) {
+                               FETCH(x, sp, length);
+                               if (print)
+                                       safeputchar(x);
                        }
-                       break;
+                       /* terminating IAC SE */
+                       if (print)
+                               (void)printf("'");
                }
+               /* terminating IAC SE */
+               if (print)
+                       (void)printf(" SE");
+               sp += 2;
+               length -= 2;
+               break;
+       default:
+               if (print)
+                       (void)printf("%s", telcmds[i]);
+               goto done;
+       }
+
+done:
+       return sp - osp;
+
+trunc:
+       return -1;
+#undef PEEK
+#undef FETCH
+}
+
+void
+telnet_print(const u_char *sp, u_int length)
+{
+       int first = 1;
+       const u_char *osp;
+       int l;
+
+       osp = sp;
+       
+       while (length > 0 && *sp == IAC) {
+               l = telnet_parse(sp, length, 0);
+               if (l < 0)
+                       break;
+
                /*
                 * now print it
                 */
                if (Xflag && 2 < vflag) {
                        if (first)
-                               printf("\nTelnet:\n");
-                       i = sp - osp;
-                       hex_print_with_offset(osp, i, off);
-                       off += i;
-                       if (i > 8)
+                               printf("\nTelnet:");
+                       hex_print_with_offset(sp, l, sp - osp);
+                       if (l > 8)
                                printf("\n\t\t\t\t");
                        else
-                               printf("%*s\t", (8 - i) * 3, "");
-                       safeputs(tnet);
-               } else {
+                               printf("%*s\t", (8 - l) * 3, "");
+               } else
                        printf("%s", (first) ? " [telnet " : ", ");
-                       safeputs(tnet);
-               }
+
+               (void)telnet_parse(sp, length, 1);
                first = 0;
+
+               sp += l;
+               length -= l;
        }
        if (!first) {
                if (Xflag && 2 < vflag)