Add a malloc/free process with garbage collector

Use it in the PPP printer.

7 files changed, 101 insertions, 5 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6a10295d..d0154774 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -771,6 +771,8 @@ set(NETDISSECT_SOURCE_LIST_C
     ipproto.c
     l2vpn.c
     machdep.c
+    netdissect.c
+    netdissect-alloc.c
     nlpid.c
     oui.c
     parsenfsfh.c
@@ -919,7 +921,6 @@ set(NETDISSECT_SOURCE_LIST_C
     print-zephyr.c
     print-zeromq.c
     ${LOCALSRC}
-    netdissect.c
     signature.c
     strtoaddr.c
     util-print.c
diff --git a/Makefile.in b/Makefile.in
index 67ee3281..f32a11d1 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -85,6 +85,8 @@ LIBNETDISSECT_SRC=\
 	ipproto.c \
 	l2vpn.c \
 	machdep.c \
+	netdissect.c \
+	netdissect-alloc.c \
 	nlpid.c \
 	oui.c \
 	parsenfsfh.c \
@@ -232,7 +234,6 @@ LIBNETDISSECT_SRC=\
 	print-wb.c \
 	print-zephyr.c \
 	print-zeromq.c \
-	netdissect.c \
 	signature.c \
 	strtoaddr.c \
 	util-print.c
@@ -278,6 +279,7 @@ HDR = \
 	mpls.h \
 	nameser.h \
 	netdissect.h \
+	netdissect-alloc.h \
 	netdissect-stdinc.h \
 	nfs.h \
 	nfsfh.h \
diff --git a/netdissect-alloc.c b/netdissect-alloc.c
new file mode 100644
index 00000000..1a40b09c
--- /dev/null
+++ b/netdissect-alloc.c
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2018 The TCPDUMP project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that: (1) source code
+ * distributions retain the above copyright notice and this paragraph
+ * in its entirety, and (2) distributions including binary code include
+ * the above copyright notice and this paragraph in its entirety in
+ * the documentation or other materials provided with the distribution.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
+ * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
+ * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE.
+ */
+
+#include <stdlib.h>
+#include "netdissect-alloc.h"
+
+/*
+ * nd_free_all() is intended to be used after a packet printing
+ */
+
+/* Add a memory chunk in allocation linked list */
+void
+nd_add_alloc_list(netdissect_options *ndo, nd_mem_chunk_t *chunkp)
+{
+	if (ndo->ndo_last_mem_p == NULL)	/* first memory allocation */
+		chunkp->prev_mem_p = NULL;
+	else					/* previous memory allocation */
+		chunkp->prev_mem_p = ndo->ndo_last_mem_p;
+	ndo->ndo_last_mem_p = chunkp;
+}
+
+/* malloc replacement, with tracking in a linked list */
+void *
+nd_malloc(netdissect_options *ndo, size_t size)
+{
+	nd_mem_chunk_t *chunkp = malloc(sizeof(nd_mem_chunk_t) + size);
+	if (chunkp == NULL)
+		return NULL;
+	nd_add_alloc_list(ndo, chunkp);
+	return chunkp + 1;
+}
+
+/* Free chunks in allocation linked list from last to first */
+void
+nd_free_all(netdissect_options *ndo)
+{
+	nd_mem_chunk_t *current, *previous;
+	current = ndo->ndo_last_mem_p;
+	while (current != NULL) {
+		previous = current->prev_mem_p;
+		free(current);
+		current = previous;
+	}
+	ndo->ndo_last_mem_p = NULL;
+}
diff --git a/netdissect-alloc.h b/netdissect-alloc.h
new file mode 100644
index 00000000..aa28a368
--- /dev/null
+++ b/netdissect-alloc.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2018 The TCPDUMP project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that: (1) source code
+ * distributions retain the above copyright notice and this paragraph
+ * in its entirety, and (2) distributions including binary code include
+ * the above copyright notice and this paragraph in its entirety in
+ * the documentation or other materials provided with the distribution.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
+ * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
+ * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE.
+ */
+
+#ifndef netdissect_alloc_h
+#define netdissect_alloc_h
+
+#include <stdarg.h>
+#include "netdissect-stdinc.h"
+#include "netdissect.h"
+
+typedef struct nd_mem_chunk {
+	void *prev_mem_p;
+	/* variable size data */
+} nd_mem_chunk_t;
+
+void nd_add_alloc_list(netdissect_options *, nd_mem_chunk_t *);
+void * nd_malloc(netdissect_options *, size_t);
+void nd_free_all(netdissect_options *);
+
+#endif /* netdissect_alloc_h */
diff --git a/netdissect.h b/netdissect.h
index 73fec2e2..5c33ed5e 100644
--- a/netdissect.h
+++ b/netdissect.h
@@ -182,6 +182,7 @@ struct netdissect_options {
 				 * LF, CR and SPACE as graphical chars
 				 */
   int ndo_Hflag;		/* dissect 802.11s draft mesh standard */
+  void *ndo_last_mem_p;		/* pointer to the last allocated memory chunk */
   int ndo_packet_number;	/* print a packet number in the beginning of line */
   int ndo_suppress_default_print; /* don't use default_print() for unknown packet types */
   int ndo_tstamp_precision;	/* requested time stamp precision */
diff --git a/print-ppp.c b/print-ppp.c
index 5230eef7..7631ca58 100644
--- a/print-ppp.c
+++ b/print-ppp.c
@@ -51,6 +51,7 @@
 #include "chdlc.h"
 #include "ethertype.h"
 #include "oui.h"
+#include "netdissect-alloc.h"
 
 /*
  * The following constants are defined by IANA. Please refer to
@@ -1401,7 +1402,7 @@ ppp_hdlc(netdissect_options *ndo,
         if (length == 0)
                 return;
 
-	b = (u_char *)malloc(length);
+	b = (u_char *)nd_malloc(ndo, length);
 	if (b == NULL)
 		return;
 
@@ -1464,12 +1465,10 @@ ppp_hdlc(netdissect_options *ndo,
 
 cleanup:
 	ndo->ndo_snapend = se;
-	free(b);
         return;
 
 trunc:
 	ndo->ndo_snapend = se;
-	free(b);
 	ND_PRINT("[|ppp]");
 }
 
diff --git a/print.c b/print.c
index fd95b512..4417a4fa 100644
--- a/print.c
+++ b/print.c
@@ -37,6 +37,7 @@
 #include "netdissect.h"
 #include "addrtoname.h"
 #include "print.h"
+#include "netdissect-alloc.h"
 
 struct printer {
 	if_printer f;
@@ -448,6 +449,7 @@ pretty_print_packet(netdissect_options *ndo, const struct pcap_pkthdr *h,
 	}
 
 	ND_PRINT("\n");
+	nd_free_all(ndo);
 }
 
 /*