fix tests

test/mip_test.c

@@ -1,7 +1,7 @@
 #define MG_ENABLE_TCPIP 1
 #define MG_ENABLE_TCPIP_DRIVER_INIT 0
 
-#include "mongoose.c"
+#include "mongoose.c" // order is important, this one first
 #include "driver_mock.c"
 
 static int s_num_tests = 0;
@@ -11,9 +11,9 @@ static int s_seg_sent = 0;
 #ifdef NO_SLEEP_ABORT
 #define ABORT() abort()
 #else
-#define ABORT()                                                 \
-      sleep(2);  /* 2s, GH print reason */                      \
-      abort();
+#define ABORT()                       \
+  sleep(2); /* 2s, GH print reason */ \
+  abort();
 #endif
 
 #define ASSERT(expr)                                            \
@@ -48,18 +48,21 @@ static void fn(struct mg_connection *c, int ev, void *ev_data) {
 static void frag_recv_fn(struct mg_connection *c, int ev, void *ev_data) {
   if (ev == MG_EV_ERROR) {
     if (s_sent_fragment) {
-      ASSERT(strcmp((char*) ev_data, "Received fragmented packet") == 0);
+      ASSERT(strcmp((char *) ev_data, "Received fragmented packet") == 0);
     }
   }
   (void) c, (void) ev_data;
 }
 
+// mock send to a non-existent peer using the listener connection
 static void frag_send_fn(struct mg_connection *c, int ev, void *ev_data) {
   static bool s_sent;
-  static int s_seg_sizes[] = {416, 416, 368};
+  static int s_seg_sizes[] = {416, 416, 368}; // based on len=1200 and MTU=500
   if (ev == MG_EV_POLL) {
     if (!s_sent) {
-      c->send.len = 1200; // setting TCP payload size
+      struct connstate *s = (struct connstate *) (c + 1);
+      s->dmss = 1500;  // mock set some destination MSS way larger
+      c->send.len = 1200;  // setting TCP payload size
       s_sent = true;
     }
   } else if (ev == MG_EV_WRITE) {
@@ -88,7 +91,7 @@ static void test_poll(void) {
 struct driver_data {
   char buf[DRIVER_BUF_SIZE];
   size_t len;
-  bool tx_ready; // data can be read from tx
+  bool tx_ready;  // data can be read from tx
 };
 
 static struct driver_data s_driver_data;
@@ -111,7 +114,7 @@ static size_t if_rx(void *buf, size_t len, struct mg_tcpip_if *ifp) {
   if (!driver_data->len) return 0;
   if (len > driver_data->len) len = driver_data->len;
   memcpy(buf, driver_data->buf, len);
-  driver_data->len = 0; // cleaning up the buffer
+  driver_data->len = 0;  // cleaning up the buffer
   return len;
 }
 
@@ -132,8 +135,8 @@ static void create_tcp_pkt(struct eth *e, struct ip *ip, uint32_t seq,
   memcpy(s_driver_data.buf, e, sizeof(*e));
   memcpy(s_driver_data.buf + sizeof(*e), ip, sizeof(*ip));
   memcpy(s_driver_data.buf + sizeof(*e) + sizeof(*ip), &t, sizeof(struct tcp));
-  s_driver_data.len = sizeof(*e) + sizeof(*ip) 
-                      + sizeof(struct tcp) + payload_len;
+  s_driver_data.len =
+      sizeof(*e) + sizeof(*ip) + sizeof(struct tcp) + payload_len;
 }
 
 static void init_tcp_handshake(struct eth *e, struct ip *ip, struct tcp *tcp,
@@ -143,9 +146,9 @@ static void init_tcp_handshake(struct eth *e, struct ip *ip, struct tcp *tcp,
   mg_mgr_poll(mgr, 0);
 
   // SYN-ACK
-  while(!received_response(&s_driver_data)) mg_mgr_poll(mgr, 0);
+  while (!received_response(&s_driver_data)) mg_mgr_poll(mgr, 0);
   tcp = (struct tcp *) (s_driver_data.buf + sizeof(struct eth) +
-                      sizeof(struct ip));
+                        sizeof(struct ip));
   ASSERT((tcp->flags == (TH_SYN | TH_ACK)));
   ASSERT((tcp->ack == mg_htonl(1001)));
 
@@ -154,6 +157,9 @@ static void init_tcp_handshake(struct eth *e, struct ip *ip, struct tcp *tcp,
   mg_mgr_poll(mgr, 0);
 }
 
+// NOTE: a 1-byte payload could be an erroneous Keep-Alive, keep length > 1 in
+// this operation, we're testing retransmissions and having len=1 won't work
+
 static void test_retransmit(void) {
   struct mg_mgr mgr;
   struct eth e;
@@ -167,12 +173,13 @@ static void test_retransmit(void) {
   mg_mgr_init(&mgr);
   memset(&mif, 0, sizeof(mif));
   memset(&s_driver_data, 0, sizeof(struct driver_data));
-  driver.init = NULL, driver.tx = if_tx, driver.poll = if_poll, driver.rx = if_rx;
+  driver.init = NULL, driver.tx = if_tx, driver.poll = if_poll,
+  driver.rx = if_rx;
   mif.driver = &driver;
   mif.driver_data = &s_driver_data;
   mg_tcpip_init(&mgr, &mif);
   mg_http_listen(&mgr, "http://0.0.0.0:0", fn, NULL);
-  mgr.conns->pfn = NULL; // HTTP handler not needed
+  mgr.conns->pfn = NULL;  // HTTP handler not needed
   mg_mgr_poll(&mgr, 0);
 
   // setting the Ethernet header
@@ -189,20 +196,20 @@ static void test_retransmit(void) {
 
   // packet with seq_no = 1001
   ip.len =
-      mg_htons(sizeof(struct ip) + sizeof(struct tcp) + /* TCP Payload */ 1);
-  create_tcp_pkt(&e, &ip, 1001, 1, TH_PUSH | TH_ACK, 1);
+      mg_htons(sizeof(struct ip) + sizeof(struct tcp) + /* TCP Payload */ 2);
+  create_tcp_pkt(&e, &ip, 1001, 1, TH_PUSH | TH_ACK, 2);
   mg_mgr_poll(&mgr, 0);
-  while(!received_response(&s_driver_data)) mg_mgr_poll(&mgr, 0);
+  while (!received_response(&s_driver_data)) mg_mgr_poll(&mgr, 0);
   t = (struct tcp *) (s_driver_data.buf + sizeof(struct eth) +
                       sizeof(struct ip));
   ASSERT((t->flags == TH_ACK));
-  ASSERT((t->ack == mg_htonl(1002))); // OK
+  ASSERT((t->ack == mg_htonl(1003)));  // OK
 
   // resend packet with seq_no = 1001 (e.g.: MIP ACK lost)
-  create_tcp_pkt(&e, &ip, 1001, 1, TH_PUSH | TH_ACK, 1);
+  create_tcp_pkt(&e, &ip, 1001, 1, TH_PUSH | TH_ACK, 2);
   mg_mgr_poll(&mgr, 0);
   start = mg_millis();
-  while(!received_response(&s_driver_data)) {
+  while (!received_response(&s_driver_data)) {
     mg_mgr_poll(&mgr, 0);
     now = mg_millis() - start;
     // we wait enough time for a reply
@@ -211,31 +218,31 @@ static void test_retransmit(void) {
       break;
     }
   }
-  ASSERT((!response_recv)); // replies should not be sent for duplicate packets
+  ASSERT((!response_recv));  // replies should not be sent for duplicate packets
 
-  // packet with seq_no = 1002 got lost/delayed, send seq_no = 1003
-  create_tcp_pkt(&e, &ip, 1003, 1, TH_PUSH | TH_ACK, 1);
+  // packet with seq_no = 1003 got lost/delayed, send seq_no = 1005
+  create_tcp_pkt(&e, &ip, 1005, 1, TH_PUSH | TH_ACK, 2);
   mg_mgr_poll(&mgr, 0);
   start = mg_millis();
-  while(!received_response(&s_driver_data)) {
+  while (!received_response(&s_driver_data)) {
     mg_mgr_poll(&mgr, 0);
     now = mg_millis() - start;
     if (now > 2 * MIP_TCP_ACK_MS)
-      ASSERT(0); // response should have been received by now
+      ASSERT(0);  // response should have been received by now
   }
   t = (struct tcp *) (s_driver_data.buf + sizeof(struct eth) +
                       sizeof(struct ip));
   ASSERT((t->flags == TH_ACK));
-  ASSERT((t->ack == mg_htonl(1002))); // dup ACK
+  ASSERT((t->ack == mg_htonl(1003)));  // dup ACK
 
-  // retransmitting packet with seq_no = 1002
-  create_tcp_pkt(&e, &ip, 1002, 1, TH_PUSH | TH_ACK, 1);
+  // retransmitting packet with seq_no = 1003
+  create_tcp_pkt(&e, &ip, 1003, 1, TH_PUSH | TH_ACK, 2);
   mg_mgr_poll(&mgr, 0);
-  while(!received_response(&s_driver_data)) mg_mgr_poll(&mgr, 0);
+  while (!received_response(&s_driver_data)) mg_mgr_poll(&mgr, 0);
   t = (struct tcp *) (s_driver_data.buf + sizeof(struct eth) +
                       sizeof(struct ip));
   ASSERT((t->flags == TH_ACK));
-  ASSERT((t->ack == mg_htonl(1003))); // OK
+  ASSERT((t->ack == mg_htonl(1005)));  // OK
 
   s_driver_data.len = 0;
   mg_mgr_free(&mgr);
@@ -252,7 +259,8 @@ static void test_frag_recv_path(void) {
   mg_mgr_init(&mgr);
   memset(&mif, 0, sizeof(mif));
   memset(&s_driver_data, 0, sizeof(struct driver_data));
-  driver.init = NULL, driver.tx = if_tx, driver.poll = if_poll, driver.rx = if_rx;
+  driver.init = NULL, driver.tx = if_tx, driver.poll = if_poll,
+  driver.rx = if_rx;
   mif.driver = &driver;
   mif.driver_data = &s_driver_data;
   mg_tcpip_init(&mgr, &mif);
@@ -273,9 +281,8 @@ static void test_frag_recv_path(void) {
   init_tcp_handshake(&e, &ip, t, &mgr);
 
   // send fragmented TCP packet
-  ip.len =
-      mg_htons(sizeof(struct ip) + sizeof(struct tcp) + 1000);
-  ip.frag |= IP_MORE_FRAGS_MSK; // setting More Fragments bit to 1
+  ip.len = mg_htons(sizeof(struct ip) + sizeof(struct tcp) + 1000);
+  ip.frag |= IP_MORE_FRAGS_MSK;  // setting More Fragments bit to 1
   create_tcp_pkt(&e, &ip, 1001, 1, TH_PUSH | TH_ACK, 1000);
   s_sent_fragment = true;
   mg_mgr_poll(&mgr, 0);
@@ -292,15 +299,15 @@ static void test_frag_send_path(void) {
   mg_mgr_init(&mgr);
   memset(&mif, 0, sizeof(mif));
   memset(&s_driver_data, 0, sizeof(struct driver_data));
-  driver.init = NULL, driver.tx = if_tx, driver.poll = if_poll, driver.rx = if_rx;
+  driver.init = NULL, driver.tx = if_tx, driver.poll = if_poll,
+  driver.rx = if_rx;
   mif.driver = &driver;
   mif.driver_data = &s_driver_data;
   mg_tcpip_init(&mgr, &mif);
-  mif.mtu = 500;
+  mif.mtu = 500;  // force ad hoc small MTU to fragment IP
   mg_http_listen(&mgr, "http://0.0.0.0:0", frag_send_fn, NULL);
   mgr.conns->pfn = NULL;
-  for (int i = 0; i < 10; i++)
-    mg_mgr_poll(&mgr, 0);
+  for (int i = 0; i < 10; i++) mg_mgr_poll(&mgr, 0);
   ASSERT(s_seg_sent == 3);
   s_driver_data.len = 0;
   mg_mgr_free(&mgr);