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authorDaniel Baumann <daniel.baumann@progress-linux.org>2021-03-04 19:22:03 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2021-03-04 20:43:22 +0000
commit22c74419e2c258319bc723351876604b3304604b (patch)
tree8c799a78d53f67388fdf42900657eda617c1306a /src/tcpstate.c
parentInitial commit. (diff)
downloaddnscap-22c74419e2c258319bc723351876604b3304604b.tar.xz
dnscap-22c74419e2c258319bc723351876604b3304604b.zip
Adding upstream version 2.0.0+debian.upstream/2.0.0+debian
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/tcpstate.c')
-rw-r--r--src/tcpstate.c141
1 files changed, 141 insertions, 0 deletions
diff --git a/src/tcpstate.c b/src/tcpstate.c
new file mode 100644
index 0000000..bfc5198
--- /dev/null
+++ b/src/tcpstate.c
@@ -0,0 +1,141 @@
+/*
+ * Copyright (c) 2018-2021, OARC, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#include "tcpstate.h"
+#include "iaddr.h"
+#include "log.h"
+#include "tcpreasm.h"
+
+#define MAX_TCP_IDLE_TIME 600
+#define MAX_TCP_IDLE_COUNT 4096
+#define TCP_GC_TIME 60
+
+tcpstate_ptr tcpstate_find(iaddr from, iaddr to, unsigned sport, unsigned dport, time_t t)
+{
+ static time_t next_gc = 0;
+ tcpstate_ptr tcpstate;
+
+ for (tcpstate = HEAD(tcpstates);
+ tcpstate != NULL;
+ tcpstate = NEXT(tcpstate, link)) {
+ if (ia_equal(tcpstate->saddr, from) && ia_equal(tcpstate->daddr, to) && tcpstate->sport == sport && tcpstate->dport == dport)
+ break;
+ }
+ if (tcpstate != NULL) {
+ tcpstate->last_use = t;
+ if (tcpstate != HEAD(tcpstates)) {
+ /* move to beginning of list */
+ UNLINK(tcpstates, tcpstate, link);
+ PREPEND(tcpstates, tcpstate, link);
+ }
+ }
+
+ if (t >= next_gc || tcpstate_count > MAX_TCP_IDLE_COUNT) {
+ /* garbage collect stale states */
+ time_t min_last_use = t - MAX_TCP_IDLE_TIME;
+ while ((tcpstate = TAIL(tcpstates)) && tcpstate->last_use < min_last_use) {
+ UNLINK(tcpstates, tcpstate, link);
+ tcpstate_count--;
+ }
+ next_gc = t + TCP_GC_TIME;
+ }
+
+ return tcpstate;
+}
+
+tcpstate_ptr tcpstate_new(iaddr from, iaddr to, unsigned sport, unsigned dport)
+{
+
+ tcpstate_ptr tcpstate = calloc(1, sizeof *tcpstate);
+ if (tcpstate == NULL) {
+ /* Out of memory; recycle the least recently used */
+ logerr("warning: out of memory, "
+ "discarding some TCP state early");
+ tcpstate = TAIL(tcpstates);
+ assert(tcpstate != NULL);
+ } else {
+ tcpstate_count++;
+ }
+ tcpstate->saddr = from;
+ tcpstate->daddr = to;
+ tcpstate->sport = sport;
+ tcpstate->dport = dport;
+ INIT_LINK(tcpstate, link);
+ PREPEND(tcpstates, tcpstate, link);
+ return tcpstate;
+}
+
+/* Discard this packet. If it's part of TCP stream, all subsequent pkts on
+ * the same tcp stream will also be discarded. */
+void tcpstate_discard(tcpstate_ptr tcpstate, const char* msg)
+{
+ if (dumptrace >= 3 && msg)
+ fprintf(stderr, "discarding packet: %s\n", msg);
+ if (tcpstate) {
+ UNLINK(tcpstates, tcpstate, link);
+ if (tcpstate->reasm) {
+ tcpreasm_free(tcpstate->reasm);
+ }
+ free(tcpstate);
+ tcpstate_count--;
+ return;
+ }
+}
+
+tcpstate_ptr _curr_tcpstate = 0;
+
+tcpstate_ptr tcpstate_getcurr(void)
+{
+ return _curr_tcpstate;
+}
+
+void tcpstate_reset(tcpstate_ptr tcpstate, const char* msg)
+{
+ if (options.allow_reset_tcpstate && tcpstate) {
+ if (dumptrace >= 3 && msg)
+ fprintf(stderr, "resetting tcpstate: %s\n", msg);
+
+ tcpstate->start = tcpstate->currseq;
+ tcpstate->maxdiff = 0;
+ tcpstate->dnslen = 0;
+ tcpstate->lastdns = tcpstate->currseq + tcpstate->currlen;
+
+ if (tcpstate->reasm) {
+ tcpreasm_reset(tcpstate->reasm);
+ tcpstate->reasm->seq_start = tcpstate->start;
+ }
+ }
+}