Fixed bugs #51606 and #51535: IPv4 reassembly could be finished although there are holes

(cherry picked from commit 5ea7f507c3d05ab86bdc14de0f016f2778db8cb3)

# Conflicts:
#	test/unit/Filelists.mk
#	test/unit/lwipopts.h

src/core/ipv4/ip4_frag.c

@@ -380,6 +380,11 @@ ip_reass_chain_frag_into_datagram_and_validate(struct ip_reassdata *ipr, struct
         }
 #endif /* IP_REASS_CHECK_OVERLAP */
         iprh_prev->next_pbuf = new_p;
+        if (iprh_prev->end != iprh->start) {
+          /* There is a fragment missing between the current
+           * and the previous fragment */
+          valid = 0;
+        }
       } else {
 #if IP_REASS_CHECK_OVERLAP
         if (iprh->end > iprh_tmp->start) {

test/unit/ip4/test_ip4.c

@@ -0,0 +1,154 @@
+#include "test_ip4.h"
+
+#include "lwip/ip4.h"
+#include "lwip/inet_chksum.h"
+#include "lwip/stats.h"
+#include "lwip/prot/ip.h"
+#include "lwip/prot/ip4.h"
+
+#if !LWIP_IPV4 || !IP_REASSEMBLY || !MIB2_STATS || !IPFRAG_STATS
+#error "This tests needs LWIP_IPV4, IP_REASSEMBLY; MIB2- and IPFRAG-statistics enabled"
+#endif
+
+/* Helper functions */
+static void
+create_ip4_input_fragment(u16_t ip_id, u16_t start, u16_t len, int last)
+{
+  struct pbuf *p;
+  struct netif *input_netif = netif_list; /* just use any netif */
+  fail_unless((start & 7) == 0);
+  fail_unless(((len & 7) == 0) || last);
+  fail_unless(input_netif != NULL);
+
+  p = pbuf_alloc(PBUF_RAW, len + sizeof(struct ip_hdr), PBUF_RAM);
+  fail_unless(p != NULL);
+  if (p != NULL) {
+    err_t err;
+    struct ip_hdr *iphdr = (struct ip_hdr *)p->payload;
+    IPH_VHL_SET(iphdr, 4, sizeof(struct ip_hdr) / 4);
+    IPH_TOS_SET(iphdr, 0);
+    IPH_LEN_SET(iphdr, lwip_htons(p->tot_len));
+    IPH_ID_SET(iphdr, lwip_htons(ip_id));
+    if (last) {
+      IPH_OFFSET_SET(iphdr, lwip_htons(start / 8));
+    } else {
+      IPH_OFFSET_SET(iphdr, lwip_htons((start / 8) | IP_MF));
+    }
+    IPH_TTL_SET(iphdr, 5);
+    IPH_PROTO_SET(iphdr, IP_PROTO_UDP);
+    IPH_CHKSUM_SET(iphdr, 0);
+    ip4_addr_copy(iphdr->src, *netif_ip4_addr(input_netif));
+    iphdr->src.addr = lwip_htonl(lwip_htonl(iphdr->src.addr) + 1);
+    ip4_addr_copy(iphdr->dest, *netif_ip4_addr(input_netif));
+    IPH_CHKSUM_SET(iphdr, inet_chksum(iphdr, sizeof(struct ip_hdr)));
+
+    err = ip4_input(p, input_netif);
+    if (err != ERR_OK) {
+      pbuf_free(p);
+    }
+    fail_unless(err == ERR_OK);
+  }
+}
+
+/* Setups/teardown functions */
+
+static void
+ip4_setup(void)
+{
+}
+
+static void
+ip4_teardown(void)
+{
+  if (netif_list->loop_first != NULL) {
+    pbuf_free(netif_list->loop_first);
+    netif_list->loop_first = NULL;
+  }
+  netif_list->loop_last = NULL;
+}
+
+
+/* Test functions */
+
+START_TEST(test_ip4_reass)
+{
+  const u16_t ip_id = 128;
+  LWIP_UNUSED_ARG(_i);
+
+  memset(&lwip_stats.mib2, 0, sizeof(lwip_stats.mib2));
+
+  create_ip4_input_fragment(ip_id, 8*200, 200, 1);
+  fail_unless(lwip_stats.ip_frag.recv == 1);
+  fail_unless(lwip_stats.ip_frag.err == 0);
+  fail_unless(lwip_stats.ip_frag.memerr == 0);
+  fail_unless(lwip_stats.ip_frag.drop == 0);
+  fail_unless(lwip_stats.mib2.ipreasmoks == 0);
+
+  create_ip4_input_fragment(ip_id, 0*200, 200, 0);
+  fail_unless(lwip_stats.ip_frag.recv == 2);
+  fail_unless(lwip_stats.ip_frag.err == 0);
+  fail_unless(lwip_stats.ip_frag.memerr == 0);
+  fail_unless(lwip_stats.ip_frag.drop == 0);
+  fail_unless(lwip_stats.mib2.ipreasmoks == 0);
+
+  create_ip4_input_fragment(ip_id, 1*200, 200, 0);
+  fail_unless(lwip_stats.ip_frag.recv == 3);
+  fail_unless(lwip_stats.ip_frag.err == 0);
+  fail_unless(lwip_stats.ip_frag.memerr == 0);
+  fail_unless(lwip_stats.ip_frag.drop == 0);
+  fail_unless(lwip_stats.mib2.ipreasmoks == 0);
+
+  create_ip4_input_fragment(ip_id, 2*200, 200, 0);
+  fail_unless(lwip_stats.ip_frag.recv == 4);
+  fail_unless(lwip_stats.ip_frag.err == 0);
+  fail_unless(lwip_stats.ip_frag.memerr == 0);
+  fail_unless(lwip_stats.ip_frag.drop == 0);
+  fail_unless(lwip_stats.mib2.ipreasmoks == 0);
+
+  create_ip4_input_fragment(ip_id, 3*200, 200, 0);
+  fail_unless(lwip_stats.ip_frag.recv == 5);
+  fail_unless(lwip_stats.ip_frag.err == 0);
+  fail_unless(lwip_stats.ip_frag.memerr == 0);
+  fail_unless(lwip_stats.ip_frag.drop == 0);
+  fail_unless(lwip_stats.mib2.ipreasmoks == 0);
+
+  create_ip4_input_fragment(ip_id, 4*200, 200, 0);
+  fail_unless(lwip_stats.ip_frag.recv == 6);
+  fail_unless(lwip_stats.ip_frag.err == 0);
+  fail_unless(lwip_stats.ip_frag.memerr == 0);
+  fail_unless(lwip_stats.ip_frag.drop == 0);
+  fail_unless(lwip_stats.mib2.ipreasmoks == 0);
+
+  create_ip4_input_fragment(ip_id, 7*200, 200, 0);
+  fail_unless(lwip_stats.ip_frag.recv == 7);
+  fail_unless(lwip_stats.ip_frag.err == 0);
+  fail_unless(lwip_stats.ip_frag.memerr == 0);
+  fail_unless(lwip_stats.ip_frag.drop == 0);
+  fail_unless(lwip_stats.mib2.ipreasmoks == 0);
+
+  create_ip4_input_fragment(ip_id, 6*200, 200, 0);
+  fail_unless(lwip_stats.ip_frag.recv == 8);
+  fail_unless(lwip_stats.ip_frag.err == 0);
+  fail_unless(lwip_stats.ip_frag.memerr == 0);
+  fail_unless(lwip_stats.ip_frag.drop == 0);
+  fail_unless(lwip_stats.mib2.ipreasmoks == 0);
+
+  create_ip4_input_fragment(ip_id, 5*200, 200, 0);
+  fail_unless(lwip_stats.ip_frag.recv == 9);
+  fail_unless(lwip_stats.ip_frag.err == 0);
+  fail_unless(lwip_stats.ip_frag.memerr == 0);
+  fail_unless(lwip_stats.ip_frag.drop == 0);
+  fail_unless(lwip_stats.mib2.ipreasmoks == 1);
+}
+END_TEST
+
+
+/** Create the suite including all tests for this module */
+Suite *
+ip4_suite(void)
+{
+  testfunc tests[] = {
+    TESTFUNC(test_ip4_reass),
+  };
+  return create_suite("IPv4", tests, sizeof(tests)/sizeof(testfunc), ip4_setup, ip4_teardown);
+}

test/unit/ip4/test_ip4.h

@@ -0,0 +1,8 @@
+#ifndef LWIP_HDR_TEST_IP4_H
+#define LWIP_HDR_TEST_IP4_H
+
+#include "../lwip_check.h"
+
+Suite* ip4_suite(void);
+
+#endif

test/unit/lwip_unittests.c

@@ -1,5 +1,6 @@
 #include "lwip_check.h"
 
+#include "ip4/test_ip4.h"
 #include "udp/test_udp.h"
 #include "tcp/test_tcp.h"
 #include "tcp/test_tcp_oos.h"
@@ -37,6 +38,7 @@ int main(void)
   SRunner *sr;
   size_t i;
   suite_getter_fn* suites[] = {
+    ip4_suite,
     udp_suite,
     tcp_suite,
     tcp_oos_suite,

test/unit/lwipopts.h

@@ -59,4 +59,7 @@
 /* Minimal changes to opt.h required for etharp unit tests: */
 #define ETHARP_SUPPORT_STATIC_ENTRIES   1
 
+/* MIB2 stats are required to check IPv4 reassembly results */
+#define MIB2_STATS                      1
+
 #endif /* LWIP_HDR_LWIPOPTS_H */