From: Francois-Xavier Le Bail <devel.fx.lebail@orange.fr>
Date: Sun, 1 Nov 2020 11:43:37 +0000 (+0100)
Subject: Add a nd_printjnp() function
X-Git-Tag: tcpdump-4.99-bp~77
X-Git-Url: https://git.tcpdump.org/tcpdump/commitdiff_plain/635e3cc92b72ca048a6b5b89b883980e4e1b4bdc

Add a nd_printjnp() function

It prints a null-padded filename (or other ASCII string), part of
the packet buffer, filtering out non-printable characters.
Stop if truncated (via GET_U_1/longjmp) or after n bytes or before
the null char, whichever occurs first.
The suffix comes from: j:longJmp, n:after N bytes, p:null-Padded.
---

diff --git a/netdissect.h b/netdissect.h
index afa5283d..854fb8a5 100644
--- a/netdissect.h
+++ b/netdissect.h
@@ -395,6 +395,7 @@ extern int nd_print(netdissect_options *, const u_char *, const u_char *);
 extern u_int nd_printztn(netdissect_options *, const u_char *, u_int, const u_char *);
 extern int nd_printn(netdissect_options *, const u_char *, u_int, const u_char *);
 extern int nd_printzp(netdissect_options *, const u_char *, u_int, const u_char *);
+extern void nd_printjnp(netdissect_options *, const u_char *, u_int);
 
 /*
  * Flags for txtproto_print().
diff --git a/util-print.c b/util-print.c
index 2524991b..3d3caa5a 100644
--- a/util-print.c
+++ b/util-print.c
@@ -228,6 +228,28 @@ nd_printzp(netdissect_options *ndo,
 	return (n == 0) ? 0 : ret;
 }
 
+/*
+ * Print a null-padded filename (or other ASCII string), part of
+ * the packet buffer, filtering out non-printable characters.
+ * Stop if truncated (via GET_U_1/longjmp) or after n bytes or before
+ * the null char, whichever occurs first.
+ * The suffix comes from: j:longJmp, n:after N bytes, p:null-Padded.
+ */
+void
+nd_printjnp(netdissect_options *ndo, const u_char *s, u_int n)
+{
+	u_char c;
+
+	while (n > 0) {
+		c = GET_U_1(s);
+		if (c == '\0')
+			break;
+		fn_print_char(ndo, c);
+		n--;
+		s++;
+	}
+}
+
 /*
  * Print the timestamp .FRAC part (Microseconds/nanoseconds)
  */