Exemple #1
0
END_TEST

/** Create an ESTABLISHED pcb and check if receive callback is called if a segment
 * overlapping rcv_nxt is received */
START_TEST(test_tcp_recv_inseq_trim)
{
  struct test_tcp_counters counters;
  struct tcp_pcb* pcb;
  struct pbuf* p;
  char data[PBUF_POOL_BUFSIZE*2];
  u16_t data_len;
  struct netif netif;
  struct test_tcp_txcounters txcounters;
  const u32_t new_data_len = 40;
  LWIP_UNUSED_ARG(_i);

  /* initialize local vars */
  test_tcp_init_netif(&netif, &txcounters, &test_local_ip, &test_netmask);
  data_len = sizeof(data);
  memset(data, 0, sizeof(data));
  /* initialize counter struct */
  memset(&counters, 0, sizeof(counters));
  counters.expected_data_len = data_len;
  counters.expected_data = data;

  /* create and initialize the pcb */
  pcb = test_tcp_new_counters_pcb(&counters);
  EXPECT_RET(pcb != NULL);
  tcp_set_state(pcb, ESTABLISHED, &test_local_ip, &test_remote_ip, TEST_LOCAL_PORT, TEST_REMOTE_PORT);

  /* create a segment (with an overlapping/old seqno so that the new data begins in the 2nd pbuf) */
  p = tcp_create_rx_segment(pcb, counters.expected_data, data_len, (u32_t)(0-(data_len-new_data_len)), 0, 0);
  EXPECT(p != NULL);
  if (p != NULL) {
    EXPECT(p->next != NULL);
    if (p->next != NULL) {
      EXPECT(p->next->next != NULL);
    }
  }
  if ((p != NULL) && (p->next != NULL) && (p->next->next != NULL)) {
    /* pass the segment to tcp_input */
    test_tcp_input(p, &netif);
    /* check if counters are as expected */
    EXPECT(counters.close_calls == 0);
    EXPECT(counters.recv_calls == 1);
    EXPECT(counters.recved_bytes == new_data_len);
    EXPECT(counters.err_calls == 0);
  }

  /* make sure the pcb is freed */
  EXPECT(MEMP_STATS_GET(used, MEMP_TCP_PCB) == 1);
  tcp_abort(pcb);
  EXPECT(MEMP_STATS_GET(used, MEMP_TCP_PCB) == 0);
}
Exemple #2
0
END_TEST

/** Create an ESTABLISHED pcb and check if receive callback is called */
START_TEST(test_tcp_recv_inseq)
{
  struct test_tcp_counters counters;
  struct tcp_pcb* pcb;
  struct pbuf* p;
  char data[] = {1, 2, 3, 4};
  ip_addr_t remote_ip, local_ip, netmask;
  u16_t data_len;
  u16_t remote_port = 0x100, local_port = 0x101;
  struct netif netif;
  struct test_tcp_txcounters txcounters;
  LWIP_UNUSED_ARG(_i);

  /* initialize local vars */
  memset(&netif, 0, sizeof(netif));
  IP_ADDR4(&local_ip, 192, 168, 1, 1);
  IP_ADDR4(&remote_ip, 192, 168, 1, 2);
  IP_ADDR4(&netmask,   255, 255, 255, 0);
  test_tcp_init_netif(&netif, &txcounters, &local_ip, &netmask);
  data_len = sizeof(data);
  /* initialize counter struct */
  memset(&counters, 0, sizeof(counters));
  counters.expected_data_len = data_len;
  counters.expected_data = data;

  /* create and initialize the pcb */
  pcb = test_tcp_new_counters_pcb(&counters);
  EXPECT_RET(pcb != NULL);
  tcp_set_state(pcb, ESTABLISHED, &local_ip, &remote_ip, local_port, remote_port);

  /* create a segment */
  p = tcp_create_rx_segment(pcb, counters.expected_data, data_len, 0, 0, 0);
  EXPECT(p != NULL);
  if (p != NULL) {
    /* pass the segment to tcp_input */
    test_tcp_input(p, &netif);
    /* check if counters are as expected */
    EXPECT(counters.close_calls == 0);
    EXPECT(counters.recv_calls == 1);
    EXPECT(counters.recved_bytes == data_len);
    EXPECT(counters.err_calls == 0);
  }

  /* make sure the pcb is freed */
  EXPECT(lwip_stats.memp[MEMP_TCP_PCB].used == 1);
  tcp_abort(pcb);
  EXPECT(lwip_stats.memp[MEMP_TCP_PCB].used == 0);
}
Exemple #3
0
END_TEST

/** Create an ESTABLISHED pcb and check if receive callback is called */
START_TEST(test_tcp_recv_inseq)
{
  struct test_tcp_counters counters;
  struct tcp_pcb* pcb;
  struct pbuf* p;
  char data[] = {1, 2, 3, 4};
  u16_t data_len;
  struct netif netif;
  struct test_tcp_txcounters txcounters;
  LWIP_UNUSED_ARG(_i);

  /* initialize local vars */
  test_tcp_init_netif(&netif, &txcounters, &test_local_ip, &test_netmask);
  data_len = sizeof(data);
  /* initialize counter struct */
  memset(&counters, 0, sizeof(counters));
  counters.expected_data_len = data_len;
  counters.expected_data = data;

  /* create and initialize the pcb */
  pcb = test_tcp_new_counters_pcb(&counters);
  EXPECT_RET(pcb != NULL);
  tcp_set_state(pcb, ESTABLISHED, &test_local_ip, &test_remote_ip, TEST_LOCAL_PORT, TEST_REMOTE_PORT);

  /* create a segment */
  p = tcp_create_rx_segment(pcb, counters.expected_data, data_len, 0, 0, 0);
  EXPECT(p != NULL);
  if (p != NULL) {
    /* pass the segment to tcp_input */
    test_tcp_input(p, &netif);
    /* check if counters are as expected */
    EXPECT(counters.close_calls == 0);
    EXPECT(counters.recv_calls == 1);
    EXPECT(counters.recved_bytes == data_len);
    EXPECT(counters.err_calls == 0);
  }

  /* make sure the pcb is freed */
  EXPECT(MEMP_STATS_GET(used, MEMP_TCP_PCB) == 1);
  tcp_abort(pcb);
  EXPECT(MEMP_STATS_GET(used, MEMP_TCP_PCB) == 0);
}
Exemple #4
0
/* this test uses 4 packets:
 * - data (len=TCP_MSS)
 * - FIN
 * - data after FIN (len=1) (invalid)
 * - 2nd FIN (invalid)
 *
 * the parameter 'delay_packet' is a bitmask that choses which on these packets is ooseq
 */
static void test_tcp_recv_ooseq_double_FINs(int delay_packet)
{
  int i, k;
  struct test_tcp_counters counters;
  struct tcp_pcb* pcb;
  struct pbuf *p_normal_fin, *p_data_after_fin, *p, *p_2nd_fin_ooseq;
  struct netif netif;
  u32_t exp_rx_calls = 0, exp_rx_bytes = 0, exp_close_calls = 0, exp_oos_pbufs = 0, exp_oos_tcplen = 0;
  int first_dropped = 0xff;

  for(i = 0; i < (int)sizeof(data_full_wnd); i++) {
    data_full_wnd[i] = (char)i;
  }

  /* initialize local vars */
  test_tcp_init_netif(&netif, NULL, &test_local_ip, &test_netmask);
  /* initialize counter struct */
  memset(&counters, 0, sizeof(counters));
  counters.expected_data_len = TCP_WND;
  counters.expected_data = data_full_wnd;

  /* create and initialize the pcb */
  pcb = test_tcp_new_counters_pcb(&counters);
  EXPECT_RET(pcb != NULL);
  tcp_set_state(pcb, ESTABLISHED, &test_local_ip, &test_remote_ip, TEST_LOCAL_PORT, TEST_REMOTE_PORT);
  pcb->rcv_nxt = 0x8000;

  /* create segments */
  p = tcp_create_rx_segment(pcb, &data_full_wnd[0], TCP_MSS, 0, 0, TCP_ACK);
  p_normal_fin = tcp_create_rx_segment(pcb, NULL, 0, TCP_MSS, 0, TCP_ACK|TCP_FIN);
  k = 1;
  p_data_after_fin = tcp_create_rx_segment(pcb, &data_full_wnd[TCP_MSS+1], k, TCP_MSS+1, 0, TCP_ACK);
  p_2nd_fin_ooseq = tcp_create_rx_segment(pcb, NULL, 0, TCP_MSS+1+k, 0, TCP_ACK|TCP_FIN);

  if(delay_packet & 1) {
    /* drop normal data */
    first_dropped = 1;
  } else {
    /* send normal data */
    test_tcp_input(p, &netif);
    exp_rx_calls++;
    exp_rx_bytes += TCP_MSS;
  }
  /* check if counters are as expected */
  check_rx_counters(pcb, &counters, exp_close_calls, exp_rx_calls, exp_rx_bytes, 0, exp_oos_pbufs, exp_oos_tcplen);

  if(delay_packet & 2) {
    /* drop FIN */
    if(first_dropped > 2) {
      first_dropped = 2;
    }
  } else {
    /* send FIN */
    test_tcp_input(p_normal_fin, &netif);
    if (first_dropped < 2) {
      /* already dropped packets, this one is ooseq */
      exp_oos_pbufs++;
      exp_oos_tcplen++;
    } else {
      /* inseq */
      exp_close_calls++;
    }
  }
  /* check if counters are as expected */
  check_rx_counters(pcb, &counters, exp_close_calls, exp_rx_calls, exp_rx_bytes, 0, exp_oos_pbufs, exp_oos_tcplen);

  if(delay_packet & 4) {
    /* drop data-after-FIN */
    if(first_dropped > 3) {
      first_dropped = 3;
    }
  } else {
    /* send data-after-FIN */
    test_tcp_input(p_data_after_fin, &netif);
    if (first_dropped < 3) {
      /* already dropped packets, this one is ooseq */
      if (delay_packet & 2) {
        /* correct FIN was ooseq */
        exp_oos_pbufs++;
        exp_oos_tcplen += k;
      }
    } else {
      /* inseq: no change */
    }
  }
  /* check if counters are as expected */
  check_rx_counters(pcb, &counters, exp_close_calls, exp_rx_calls, exp_rx_bytes, 0, exp_oos_pbufs, exp_oos_tcplen);

  if(delay_packet & 8) {
    /* drop 2nd-FIN */
    if(first_dropped > 4) {
      first_dropped = 4;
    }
  } else {
    /* send 2nd-FIN */
    test_tcp_input(p_2nd_fin_ooseq, &netif);
    if (first_dropped < 3) {
      /* already dropped packets, this one is ooseq */
      if (delay_packet & 2) {
        /* correct FIN was ooseq */
        exp_oos_pbufs++;
        exp_oos_tcplen++;
      }
    } else {
      /* inseq: no change */
    }
  }
  /* check if counters are as expected */
  check_rx_counters(pcb, &counters, exp_close_calls, exp_rx_calls, exp_rx_bytes, 0, exp_oos_pbufs, exp_oos_tcplen);

  if(delay_packet & 1) {
    /* dropped normal data before */
    test_tcp_input(p, &netif);
    exp_rx_calls++;
    exp_rx_bytes += TCP_MSS;
    if((delay_packet & 2) == 0) {
      /* normal FIN was NOT delayed */
      exp_close_calls++;
      exp_oos_pbufs = exp_oos_tcplen = 0;
    }
  }
  /* check if counters are as expected */
  check_rx_counters(pcb, &counters, exp_close_calls, exp_rx_calls, exp_rx_bytes, 0, exp_oos_pbufs, exp_oos_tcplen);

  if(delay_packet & 2) {
    /* dropped normal FIN before */
    test_tcp_input(p_normal_fin, &netif);
    exp_close_calls++;
    exp_oos_pbufs = exp_oos_tcplen = 0;
  }
  /* check if counters are as expected */
  check_rx_counters(pcb, &counters, exp_close_calls, exp_rx_calls, exp_rx_bytes, 0, exp_oos_pbufs, exp_oos_tcplen);

  if(delay_packet & 4) {
    /* dropped data-after-FIN before */
    test_tcp_input(p_data_after_fin, &netif);
  }
  /* check if counters are as expected */
  check_rx_counters(pcb, &counters, exp_close_calls, exp_rx_calls, exp_rx_bytes, 0, exp_oos_pbufs, exp_oos_tcplen);

  if(delay_packet & 8) {
    /* dropped 2nd-FIN before */
    test_tcp_input(p_2nd_fin_ooseq, &netif);
  }
  /* check if counters are as expected */
  check_rx_counters(pcb, &counters, exp_close_calls, exp_rx_calls, exp_rx_bytes, 0, exp_oos_pbufs, exp_oos_tcplen);

  /* check that ooseq data has been dumped */
  EXPECT(pcb->ooseq == NULL);

  /* make sure the pcb is freed */
  EXPECT(MEMP_STATS_GET(used, MEMP_TCP_PCB) == 1);
  tcp_abort(pcb);
  EXPECT(MEMP_STATS_GET(used, MEMP_TCP_PCB) == 0);
}
Exemple #5
0
END_TEST

START_TEST(test_tcp_recv_ooseq_max_pbufs)
{
#if TCP_OOSEQ_MAX_PBUFS && (TCP_OOSEQ_MAX_PBUFS < ((TCP_WND / TCP_MSS) + 1)) && (PBUF_POOL_BUFSIZE >= (TCP_MSS + PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN))
  int i;
  struct test_tcp_counters counters;
  struct tcp_pcb* pcb;
  struct pbuf *p_ovr;
  struct netif netif;
  int datalen = 0;
  int datalen2;

  for(i = 0; i < sizeof(data_full_wnd); i++) {
    data_full_wnd[i] = (char)i;
  }

  /* initialize local vars */
  test_tcp_init_netif(&netif, NULL, &test_local_ip, &test_netmask);
  /* initialize counter struct */
  memset(&counters, 0, sizeof(counters));
  counters.expected_data_len = TCP_WND;
  counters.expected_data = data_full_wnd;

  /* create and initialize the pcb */
  pcb = test_tcp_new_counters_pcb(&counters);
  EXPECT_RET(pcb != NULL);
  tcp_set_state(pcb, ESTABLISHED, &local_ip, &remote_ip, TEST_LOCAL_PORT, TEST_REMOTE_PORT);
  pcb->rcv_nxt = 0x8000;

  /* don't 'recv' the first segment (1 byte) so that all other segments will be ooseq */

  /* create segments and 'recv' them */
  for(i = 1; i <= TCP_OOSEQ_MAX_PBUFS; i++) {
    int count;
    struct pbuf *p = tcp_create_rx_segment(pcb, &data_full_wnd[i],
                                           1, i, 0, TCP_ACK);
    EXPECT_RET(p != NULL);
    EXPECT_RET(p->next == NULL);
    /* pass the segment to tcp_input */
    test_tcp_input(p, &netif);
    /* check if counters are as expected */
    EXPECT(counters.close_calls == 0);
    EXPECT(counters.recv_calls == 0);
    EXPECT(counters.recved_bytes == 0);
    EXPECT(counters.err_calls == 0);
    /* check ooseq queue */
    count = tcp_oos_pbuf_count(pcb);
    EXPECT_OOSEQ(count == i);
    datalen = tcp_oos_tcplen(pcb);
    EXPECT_OOSEQ(datalen == i);
  }

  /* pass in one more segment, overrunning the limit */
  p_ovr = tcp_create_rx_segment(pcb, &data_full_wnd[i+1], 1, i+1, 0, TCP_ACK);
  EXPECT_RET(p_ovr != NULL);
  /* pass the segment to tcp_input */
  test_tcp_input(p_ovr, &netif);
  /* check if counters are as expected */
  EXPECT(counters.close_calls == 0);
  EXPECT(counters.recv_calls == 0);
  EXPECT(counters.recved_bytes == 0);
  EXPECT(counters.err_calls == 0);
  /* check ooseq queue (ensure the new segment was not accepted) */
  EXPECT_OOSEQ(tcp_oos_count(pcb) == (i-1));
  datalen2 = tcp_oos_tcplen(pcb);
  EXPECT_OOSEQ(datalen2 == (i-1));

  /* make sure the pcb is freed */
  EXPECT(MEMP_STATS_GET(used, MEMP_TCP_PCB) == 1);
  tcp_abort(pcb);
  EXPECT(MEMP_STATS_GET(used, MEMP_TCP_PCB) == 0);
#endif /* TCP_OOSEQ_MAX_PBUFS && (TCP_OOSEQ_MAX_BYTES < (TCP_WND + 1)) && (PBUF_POOL_BUFSIZE >= (TCP_MSS + PBUF_LINK_ENCAPSULATION_HLEN + PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN)) */
  LWIP_UNUSED_ARG(_i);
}
Exemple #6
0
END_TEST

/** similar to above test, except seqno starts near the max rxwin */
START_TEST(test_tcp_recv_ooseq_overrun_rxwin_edge)
{
#if !TCP_OOSEQ_MAX_BYTES && !TCP_OOSEQ_MAX_PBUFS
  int i, k;
  struct test_tcp_counters counters;
  struct tcp_pcb* pcb;
  struct pbuf *pinseq, *p_ovr;
  struct netif netif;
  int datalen = 0;
  int datalen2;

  for(i = 0; i < (int)sizeof(data_full_wnd); i++) {
    data_full_wnd[i] = (char)i;
  }

  /* initialize local vars */
  test_tcp_init_netif(&netif, NULL, &test_local_ip, &test_netmask);
  /* initialize counter struct */
  memset(&counters, 0, sizeof(counters));
  counters.expected_data_len = TCP_WND;
  counters.expected_data = data_full_wnd;

  /* create and initialize the pcb */
  pcb = test_tcp_new_counters_pcb(&counters);
  EXPECT_RET(pcb != NULL);
  tcp_set_state(pcb, ESTABLISHED, &test_local_ip, &test_remote_ip, TEST_LOCAL_PORT, TEST_REMOTE_PORT);
  pcb->rcv_nxt = 0xffffffff - (TCP_WND / 2);

  /* create segments */
  /* pinseq is sent as last segment! */
  pinseq = tcp_create_rx_segment(pcb, &data_full_wnd[0],  TCP_MSS, 0, 0, TCP_ACK);

  for(i = TCP_MSS, k = 0; i < TCP_WND; i += TCP_MSS, k++) {
    int count, expected_datalen;
    struct pbuf *p = tcp_create_rx_segment(pcb, &data_full_wnd[TCP_MSS*(k+1)],
                                           TCP_MSS, TCP_MSS*(k+1), 0, TCP_ACK);
    EXPECT_RET(p != NULL);
    /* pass the segment to tcp_input */
    test_tcp_input(p, &netif);
    /* check if counters are as expected */
    EXPECT(counters.close_calls == 0);
    EXPECT(counters.recv_calls == 0);
    EXPECT(counters.recved_bytes == 0);
    EXPECT(counters.err_calls == 0);
    /* check ooseq queue */
    count = tcp_oos_count(pcb);
    EXPECT_OOSEQ(count == k+1);
    datalen = tcp_oos_tcplen(pcb);
    if (i + TCP_MSS < TCP_WND) {
      expected_datalen = (k+1)*TCP_MSS;
    } else {
      expected_datalen = TCP_WND - TCP_MSS;
    }
    if (datalen != expected_datalen) {
      EXPECT_OOSEQ(datalen == expected_datalen);
    }
  }

  /* pass in one more segment, cleary overrunning the rxwin */
  p_ovr = tcp_create_rx_segment(pcb, &data_full_wnd[TCP_MSS*(k+1)], TCP_MSS, TCP_MSS*(k+1), 0, TCP_ACK);
  EXPECT_RET(p_ovr != NULL);
  /* pass the segment to tcp_input */
  test_tcp_input(p_ovr, &netif);
  /* check if counters are as expected */
  EXPECT(counters.close_calls == 0);
  EXPECT(counters.recv_calls == 0);
  EXPECT(counters.recved_bytes == 0);
  EXPECT(counters.err_calls == 0);
  /* check ooseq queue */
  EXPECT_OOSEQ(tcp_oos_count(pcb) == k);
  datalen2 = tcp_oos_tcplen(pcb);
  EXPECT_OOSEQ(datalen == datalen2);

  /* now pass inseq */
  test_tcp_input(pinseq, &netif);
  EXPECT(pcb->ooseq == NULL);

  /* make sure the pcb is freed */
  EXPECT(MEMP_STATS_GET(used, MEMP_TCP_PCB) == 1);
  tcp_abort(pcb);
  EXPECT(MEMP_STATS_GET(used, MEMP_TCP_PCB) == 0);
#endif /* !TCP_OOSEQ_MAX_BYTES && !TCP_OOSEQ_MAX_PBUFS */
  LWIP_UNUSED_ARG(_i);
}
Exemple #7
0
END_TEST


/** create multiple segments and pass them to tcp_input in a wrong
 * order to see if ooseq-caching works correctly
 * FIN is received IN-SEQUENCE at the end */
START_TEST(test_tcp_recv_ooseq_FIN_INSEQ)
{
  struct test_tcp_counters counters;
  struct tcp_pcb* pcb;
  struct pbuf *p_1_2, *p_4_8, *p_3_11, *p_2_12, *p_15_1, *p_15_1a, *pinseq, *pinseqFIN;
  char data[] = {
     1,  2,  3,  4,
     5,  6,  7,  8,
     9, 10, 11, 12,
    13, 14, 15, 16};
  u16_t data_len;
  struct netif netif;
  LWIP_UNUSED_ARG(_i);

  /* initialize local vars */
  test_tcp_init_netif(&netif, NULL, &test_local_ip, &test_netmask);
  data_len = sizeof(data);
  /* initialize counter struct */
  memset(&counters, 0, sizeof(counters));
  counters.expected_data_len = data_len;
  counters.expected_data = data;

  /* create and initialize the pcb */
  pcb = test_tcp_new_counters_pcb(&counters);
  EXPECT_RET(pcb != NULL);
  tcp_set_state(pcb, ESTABLISHED, &test_local_ip, &test_remote_ip, TEST_LOCAL_PORT, TEST_REMOTE_PORT);

  /* create segments */
  /* p1: 7 bytes - 2 before FIN */
  /*     seqno: 1..2 */
  p_1_2  = tcp_create_rx_segment(pcb, &data[1],  2, 1, 0, TCP_ACK);
  /* p2: 4 bytes before p1, including the first 4 bytes of p1 (partly duplicate) */
  /*     seqno: 4..11 */
  p_4_8  = tcp_create_rx_segment(pcb, &data[4],  8, 4, 0, TCP_ACK);
  /* p3: same as p2 but 2 bytes longer and one byte more at the front */
  /*     seqno: 3..13 */
  p_3_11 = tcp_create_rx_segment(pcb, &data[3], 11, 3, 0, TCP_ACK);
  /* p4: 13 bytes - 2 before FIN - should be ignored as contained in p1 and p3 */
  /*     seqno: 2..13 */
  p_2_12 = tcp_create_rx_segment(pcb, &data[2], 12, 2, 0, TCP_ACK);
  /* pinseq is the first segment that is held back to create ooseq! */
  /*     seqno: 0..3 */
  pinseq = tcp_create_rx_segment(pcb, &data[0],  4, 0, 0, TCP_ACK);
  /* p5: last byte before FIN */
  /*     seqno: 15 */
  p_15_1 = tcp_create_rx_segment(pcb, &data[15], 1, 15, 0, TCP_ACK);
  /* p6: same as p5, should be ignored */
  p_15_1a= tcp_create_rx_segment(pcb, &data[15], 1, 15, 0, TCP_ACK);
  /* pinseqFIN: last 2 bytes plus FIN */
  /*     only segment containing seqno 14 and FIN */
  pinseqFIN = tcp_create_rx_segment(pcb,  &data[14], 2, 14, 0, TCP_ACK|TCP_FIN);
  EXPECT(pinseq != NULL);
  EXPECT(p_1_2 != NULL);
  EXPECT(p_4_8 != NULL);
  EXPECT(p_3_11 != NULL);
  EXPECT(p_2_12 != NULL);
  EXPECT(p_15_1 != NULL);
  EXPECT(p_15_1a != NULL);
  EXPECT(pinseqFIN != NULL);
  if ((pinseq != NULL) && (p_1_2 != NULL) && (p_4_8 != NULL) && (p_3_11 != NULL) && (p_2_12 != NULL)
    && (p_15_1 != NULL) && (p_15_1a != NULL) && (pinseqFIN != NULL)) {
    /* pass the segment to tcp_input */
    test_tcp_input(p_1_2, &netif);
    /* check if counters are as expected */
    EXPECT(counters.close_calls == 0);
    EXPECT(counters.recv_calls == 0);
    EXPECT(counters.recved_bytes == 0);
    EXPECT(counters.err_calls == 0);
    /* check ooseq queue */
    EXPECT_OOSEQ(tcp_oos_count(pcb) == 1);
    EXPECT_OOSEQ(tcp_oos_seg_seqno(pcb, 0) == 1);
    EXPECT_OOSEQ(tcp_oos_seg_tcplen(pcb, 0) == 2);

    /* pass the segment to tcp_input */
    test_tcp_input(p_4_8, &netif);
    /* check if counters are as expected */
    EXPECT(counters.close_calls == 0);
    EXPECT(counters.recv_calls == 0);
    EXPECT(counters.recved_bytes == 0);
    EXPECT(counters.err_calls == 0);
    /* check ooseq queue */
    EXPECT_OOSEQ(tcp_oos_count(pcb) == 2);
    EXPECT_OOSEQ(tcp_oos_seg_seqno(pcb, 0) == 1);
    EXPECT_OOSEQ(tcp_oos_seg_tcplen(pcb, 0) == 2);
    EXPECT_OOSEQ(tcp_oos_seg_seqno(pcb, 1) == 4);
    EXPECT_OOSEQ(tcp_oos_seg_tcplen(pcb, 1) == 8);

    /* pass the segment to tcp_input */
    test_tcp_input(p_3_11, &netif);
    /* check if counters are as expected */
    EXPECT(counters.close_calls == 0);
    EXPECT(counters.recv_calls == 0);
    EXPECT(counters.recved_bytes == 0);
    EXPECT(counters.err_calls == 0);
    /* check ooseq queue */
    EXPECT_OOSEQ(tcp_oos_count(pcb) == 2);
    EXPECT_OOSEQ(tcp_oos_seg_seqno(pcb, 0) == 1);
    EXPECT_OOSEQ(tcp_oos_seg_tcplen(pcb, 0) == 2);
    /* p_3_11 has removed p_4_8 from ooseq */
    EXPECT_OOSEQ(tcp_oos_seg_seqno(pcb, 1) == 3);
    EXPECT_OOSEQ(tcp_oos_seg_tcplen(pcb, 1) == 11);

    /* pass the segment to tcp_input */
    test_tcp_input(p_2_12, &netif);
    /* check if counters are as expected */
    EXPECT(counters.close_calls == 0);
    EXPECT(counters.recv_calls == 0);
    EXPECT(counters.recved_bytes == 0);
    EXPECT(counters.err_calls == 0);
    /* check ooseq queue */
    EXPECT_OOSEQ(tcp_oos_count(pcb) == 2);
    EXPECT_OOSEQ(tcp_oos_seg_seqno(pcb, 0) == 1);
    EXPECT_OOSEQ(tcp_oos_seg_tcplen(pcb, 0) == 1);
    EXPECT_OOSEQ(tcp_oos_seg_seqno(pcb, 1) == 2);
    EXPECT_OOSEQ(tcp_oos_seg_tcplen(pcb, 1) == 12);

    /* pass the segment to tcp_input */
    test_tcp_input(pinseq, &netif);
    /* check if counters are as expected */
    EXPECT(counters.close_calls == 0);
    EXPECT(counters.recv_calls == 1);
    EXPECT(counters.recved_bytes == 14);
    EXPECT(counters.err_calls == 0);
    EXPECT(pcb->ooseq == NULL);

    /* pass the segment to tcp_input */
    test_tcp_input(p_15_1, &netif);
    /* check if counters are as expected */
    EXPECT(counters.close_calls == 0);
    EXPECT(counters.recv_calls == 1);
    EXPECT(counters.recved_bytes == 14);
    EXPECT(counters.err_calls == 0);
    /* check ooseq queue */
    EXPECT_OOSEQ(tcp_oos_count(pcb) == 1);
    EXPECT_OOSEQ(tcp_oos_seg_seqno(pcb, 0) == 15);
    EXPECT_OOSEQ(tcp_oos_seg_tcplen(pcb, 0) == 1);

    /* pass the segment to tcp_input */
    test_tcp_input(p_15_1a, &netif);
    /* check if counters are as expected */
    EXPECT(counters.close_calls == 0);
    EXPECT(counters.recv_calls == 1);
    EXPECT(counters.recved_bytes == 14);
    EXPECT(counters.err_calls == 0);
    /* check ooseq queue: unchanged */
    EXPECT_OOSEQ(tcp_oos_count(pcb) == 1);
    EXPECT_OOSEQ(tcp_oos_seg_seqno(pcb, 0) == 15);
    EXPECT_OOSEQ(tcp_oos_seg_tcplen(pcb, 0) == 1);

    /* pass the segment to tcp_input */
    test_tcp_input(pinseqFIN, &netif);
    /* check if counters are as expected */
    EXPECT(counters.close_calls == 1);
    EXPECT(counters.recv_calls == 2);
    EXPECT(counters.recved_bytes == data_len);
    EXPECT(counters.err_calls == 0);
    EXPECT(pcb->ooseq == NULL);
  }

  /* make sure the pcb is freed */
  EXPECT(MEMP_STATS_GET(used, MEMP_TCP_PCB) == 1);
  tcp_abort(pcb);
  EXPECT(MEMP_STATS_GET(used, MEMP_TCP_PCB) == 0);
}
Exemple #8
0
END_TEST

/** Provoke fast retransmission by duplicate ACKs and then recover by ACKing all sent data.
 * At the end, send more data. */
static void test_tcp_tx_full_window_lost(u8_t zero_window_probe_from_unsent)
{
  struct netif netif;
  struct test_tcp_txcounters txcounters;
  struct test_tcp_counters counters;
  struct tcp_pcb* pcb;
  struct pbuf *p;
  ip_addr_t remote_ip, local_ip, netmask;
  u16_t remote_port = 0x100, local_port = 0x101;
  err_t err;
  u16_t sent_total, i;
  u8_t expected = 0xFE;

  for (i = 0; i < sizeof(tx_data); i++) {
    u8_t d = (u8_t)i;
    if (d == 0xFE) {
      d = 0xF0;
    }
    tx_data[i] = d;
  }
  if (zero_window_probe_from_unsent) {
    tx_data[TCP_WND] = expected;
  } else {
    tx_data[0] = expected;
  }

  /* initialize local vars */
  IP_ADDR4(&local_ip,  192, 168,   1, 1);
  IP_ADDR4(&remote_ip, 192, 168,   1, 2);
  IP_ADDR4(&netmask,   255, 255, 255, 0);
  test_tcp_init_netif(&netif, &txcounters, &local_ip, &netmask);
  memset(&counters, 0, sizeof(counters));
  memset(&txcounters, 0, sizeof(txcounters));

  /* create and initialize the pcb */
  pcb = test_tcp_new_counters_pcb(&counters);
  EXPECT_RET(pcb != NULL);
  tcp_set_state(pcb, ESTABLISHED, &local_ip, &remote_ip, local_port, remote_port);
  pcb->mss = TCP_MSS;
  /* disable initial congestion window (we don't send a SYN here...) */
  pcb->cwnd = pcb->snd_wnd;

  /* send a full window (minus 1 packets) of TCP data in MSS-sized chunks */
  sent_total = 0;
  if ((TCP_WND - TCP_MSS) % TCP_MSS != 0) {
    u16_t initial_data_len = (TCP_WND - TCP_MSS) % TCP_MSS;
    err = tcp_write(pcb, &tx_data[sent_total], initial_data_len, TCP_WRITE_FLAG_COPY);
    EXPECT_RET(err == ERR_OK);
    err = tcp_output(pcb);
    EXPECT_RET(err == ERR_OK);
    EXPECT(txcounters.num_tx_calls == 1);
    EXPECT(txcounters.num_tx_bytes == initial_data_len + 40U);
    memset(&txcounters, 0, sizeof(txcounters));
    sent_total += initial_data_len;
  }
  for (; sent_total < (TCP_WND - TCP_MSS); sent_total += TCP_MSS) {
    err = tcp_write(pcb, &tx_data[sent_total], TCP_MSS, TCP_WRITE_FLAG_COPY);
    EXPECT_RET(err == ERR_OK);
    err = tcp_output(pcb);
    EXPECT_RET(err == ERR_OK);
    EXPECT(txcounters.num_tx_calls == 1);
    EXPECT(txcounters.num_tx_bytes == TCP_MSS + 40U);
    memset(&txcounters, 0, sizeof(txcounters));
  }
  EXPECT(sent_total == (TCP_WND - TCP_MSS));

  /* now ACK the packet before the first */
  p = tcp_create_rx_segment(pcb, NULL, 0, 0, 0, TCP_ACK);
  test_tcp_input(p, &netif);
  /* ensure this didn't trigger a retransmission */
  EXPECT(txcounters.num_tx_calls == 0);
  EXPECT(txcounters.num_tx_bytes == 0);

  EXPECT(pcb->persist_backoff == 0);
  /* send the last packet, now a complete window has been sent */
  err = tcp_write(pcb, &tx_data[sent_total], TCP_MSS, TCP_WRITE_FLAG_COPY);
  sent_total += TCP_MSS;
  EXPECT_RET(err == ERR_OK);
  err = tcp_output(pcb);
  EXPECT_RET(err == ERR_OK);
  EXPECT(txcounters.num_tx_calls == 1);
  EXPECT(txcounters.num_tx_bytes == TCP_MSS + 40U);
  memset(&txcounters, 0, sizeof(txcounters));
  EXPECT(pcb->persist_backoff == 0);

  if (zero_window_probe_from_unsent) {
    /* ACK all data but close the TX window */
    p = tcp_create_rx_segment_wnd(pcb, NULL, 0, 0, TCP_WND, TCP_ACK, 0);
    test_tcp_input(p, &netif);
    /* ensure this didn't trigger any transmission */
    EXPECT(txcounters.num_tx_calls == 0);
    EXPECT(txcounters.num_tx_bytes == 0);
    EXPECT(pcb->persist_backoff == 1);
  }

  /* send one byte more (out of window) -> persist timer starts */
  err = tcp_write(pcb, &tx_data[sent_total], 1, TCP_WRITE_FLAG_COPY);
  EXPECT_RET(err == ERR_OK);
  err = tcp_output(pcb);
  EXPECT_RET(err == ERR_OK);
  EXPECT(txcounters.num_tx_calls == 0);
  EXPECT(txcounters.num_tx_bytes == 0);
  memset(&txcounters, 0, sizeof(txcounters));
  if (!zero_window_probe_from_unsent) {
    /* no persist timer unless a zero window announcement has been received */
    EXPECT(pcb->persist_backoff == 0);
  } else {
    EXPECT(pcb->persist_backoff == 1);

    /* call tcp_timer some more times to let persist timer count up */
    for (i = 0; i < 4; i++) {
      test_tcp_tmr();
      EXPECT(txcounters.num_tx_calls == 0);
      EXPECT(txcounters.num_tx_bytes == 0);
    }

    /* this should trigger the zero-window-probe */
    txcounters.copy_tx_packets = 1;
    test_tcp_tmr();
    txcounters.copy_tx_packets = 0;
    EXPECT(txcounters.num_tx_calls == 1);
    EXPECT(txcounters.num_tx_bytes == 1 + 40U);
    EXPECT(txcounters.tx_packets != NULL);
    if (txcounters.tx_packets != NULL) {
      u8_t sent;
      u16_t ret;
      ret = pbuf_copy_partial(txcounters.tx_packets, &sent, 1, 40U);
      EXPECT(ret == 1);
      EXPECT(sent == expected);
    }
    if (txcounters.tx_packets != NULL) {
      pbuf_free(txcounters.tx_packets);
      txcounters.tx_packets = NULL;
    }
  }

  /* make sure the pcb is freed */
  EXPECT_RET(lwip_stats.memp[MEMP_TCP_PCB].used == 1);
  tcp_abort(pcb);
  EXPECT_RET(lwip_stats.memp[MEMP_TCP_PCB].used == 0);
}
Exemple #9
0
END_TEST


/** Provoke fast retransmission by duplicate ACKs and then recover by ACKing all sent data.
 * At the end, send more data. */
START_TEST(test_tcp_fast_retx_recover)
{
  struct netif netif;
  struct test_tcp_txcounters txcounters;
  struct test_tcp_counters counters;
  struct tcp_pcb* pcb;
  struct pbuf* p;
  char data1[] = { 1,  2,  3,  4};
  char data2[] = { 5,  6,  7,  8};
  char data3[] = { 9, 10, 11, 12};
  char data4[] = {13, 14, 15, 16};
  char data5[] = {17, 18, 19, 20};
  char data6[] = {21, 22, 23, 24};
  ip_addr_t remote_ip, local_ip, netmask;
  u16_t remote_port = 0x100, local_port = 0x101;
  err_t err;
  LWIP_UNUSED_ARG(_i);

  /* initialize local vars */
  IP_ADDR4(&local_ip,  192, 168,   1, 1);
  IP_ADDR4(&remote_ip, 192, 168,   1, 2);
  IP_ADDR4(&netmask,   255, 255, 255, 0);
  test_tcp_init_netif(&netif, &txcounters, &local_ip, &netmask);
  memset(&counters, 0, sizeof(counters));

  /* create and initialize the pcb */
  pcb = test_tcp_new_counters_pcb(&counters);
  EXPECT_RET(pcb != NULL);
  tcp_set_state(pcb, ESTABLISHED, &local_ip, &remote_ip, local_port, remote_port);
  pcb->mss = TCP_MSS;
  /* disable initial congestion window (we don't send a SYN here...) */
  pcb->cwnd = pcb->snd_wnd;

  /* send data1 */
  err = tcp_write(pcb, data1, sizeof(data1), TCP_WRITE_FLAG_COPY);
  EXPECT_RET(err == ERR_OK);
  err = tcp_output(pcb);
  EXPECT_RET(err == ERR_OK);
  EXPECT_RET(txcounters.num_tx_calls == 1);
  EXPECT_RET(txcounters.num_tx_bytes == sizeof(data1) + sizeof(struct tcp_hdr) + sizeof(struct ip_hdr));
  memset(&txcounters, 0, sizeof(txcounters));
 /* "recv" ACK for data1 */
  p = tcp_create_rx_segment(pcb, NULL, 0, 0, 4, TCP_ACK);
  EXPECT_RET(p != NULL);
  test_tcp_input(p, &netif);
  EXPECT_RET(txcounters.num_tx_calls == 0);
  EXPECT_RET(pcb->unacked == NULL);
  /* send data2 */
  err = tcp_write(pcb, data2, sizeof(data2), TCP_WRITE_FLAG_COPY);
  EXPECT_RET(err == ERR_OK);
  err = tcp_output(pcb);
  EXPECT_RET(err == ERR_OK);
  EXPECT_RET(txcounters.num_tx_calls == 1);
  EXPECT_RET(txcounters.num_tx_bytes == sizeof(data2) + sizeof(struct tcp_hdr) + sizeof(struct ip_hdr));
  memset(&txcounters, 0, sizeof(txcounters));
  /* duplicate ACK for data1 (data2 is lost) */
  p = tcp_create_rx_segment(pcb, NULL, 0, 0, 0, TCP_ACK);
  EXPECT_RET(p != NULL);
  test_tcp_input(p, &netif);
  EXPECT_RET(txcounters.num_tx_calls == 0);
  EXPECT_RET(pcb->dupacks == 1);
  /* send data3 */
  err = tcp_write(pcb, data3, sizeof(data3), TCP_WRITE_FLAG_COPY);
  EXPECT_RET(err == ERR_OK);
  err = tcp_output(pcb);
  EXPECT_RET(err == ERR_OK);
  /* nagle enabled, no tx calls */
  EXPECT_RET(txcounters.num_tx_calls == 0);
  EXPECT_RET(txcounters.num_tx_bytes == 0);
  memset(&txcounters, 0, sizeof(txcounters));
  /* 2nd duplicate ACK for data1 (data2 and data3 are lost) */
  p = tcp_create_rx_segment(pcb, NULL, 0, 0, 0, TCP_ACK);
  EXPECT_RET(p != NULL);
  test_tcp_input(p, &netif);
  EXPECT_RET(txcounters.num_tx_calls == 0);
  EXPECT_RET(pcb->dupacks == 2);
  /* queue data4, don't send it (unsent-oversize is != 0) */
  err = tcp_write(pcb, data4, sizeof(data4), TCP_WRITE_FLAG_COPY);
  EXPECT_RET(err == ERR_OK);
  /* 3nd duplicate ACK for data1 (data2 and data3 are lost) -> fast retransmission */
  p = tcp_create_rx_segment(pcb, NULL, 0, 0, 0, TCP_ACK);
  EXPECT_RET(p != NULL);
  test_tcp_input(p, &netif);
  /*EXPECT_RET(txcounters.num_tx_calls == 1);*/
  EXPECT_RET(pcb->dupacks == 3);
  memset(&txcounters, 0, sizeof(txcounters));
  /* @todo: check expected data?*/
  
  /* send data5, not output yet */
  err = tcp_write(pcb, data5, sizeof(data5), TCP_WRITE_FLAG_COPY);
  EXPECT_RET(err == ERR_OK);
  /*err = tcp_output(pcb);
  EXPECT_RET(err == ERR_OK);*/
  EXPECT_RET(txcounters.num_tx_calls == 0);
  EXPECT_RET(txcounters.num_tx_bytes == 0);
  memset(&txcounters, 0, sizeof(txcounters));
  {
    int i = 0;
    do
    {
      err = tcp_write(pcb, data6, TCP_MSS, TCP_WRITE_FLAG_COPY);
      i++;
    }while(err == ERR_OK);
    EXPECT_RET(err != ERR_OK);
  }
  err = tcp_output(pcb);
  EXPECT_RET(err == ERR_OK);
  /*EXPECT_RET(txcounters.num_tx_calls == 0);
  EXPECT_RET(txcounters.num_tx_bytes == 0);*/
  memset(&txcounters, 0, sizeof(txcounters));

  /* send even more data */
  err = tcp_write(pcb, data5, sizeof(data5), TCP_WRITE_FLAG_COPY);
  EXPECT_RET(err == ERR_OK);
  err = tcp_output(pcb);
  EXPECT_RET(err == ERR_OK);
  /* ...and even more data */
  err = tcp_write(pcb, data5, sizeof(data5), TCP_WRITE_FLAG_COPY);
  EXPECT_RET(err == ERR_OK);
  err = tcp_output(pcb);
  EXPECT_RET(err == ERR_OK);
  /* ...and even more data */
  err = tcp_write(pcb, data5, sizeof(data5), TCP_WRITE_FLAG_COPY);
  EXPECT_RET(err == ERR_OK);
  err = tcp_output(pcb);
  EXPECT_RET(err == ERR_OK);
  /* ...and even more data */
  err = tcp_write(pcb, data5, sizeof(data5), TCP_WRITE_FLAG_COPY);
  EXPECT_RET(err == ERR_OK);
  err = tcp_output(pcb);
  EXPECT_RET(err == ERR_OK);

  /* send ACKs for data2 and data3 */
  p = tcp_create_rx_segment(pcb, NULL, 0, 0, 12, TCP_ACK);
  EXPECT_RET(p != NULL);
  test_tcp_input(p, &netif);
  /*EXPECT_RET(txcounters.num_tx_calls == 0);*/

  /* ...and even more data */
  err = tcp_write(pcb, data5, sizeof(data5), TCP_WRITE_FLAG_COPY);
  EXPECT_RET(err == ERR_OK);
  err = tcp_output(pcb);
  EXPECT_RET(err == ERR_OK);
  /* ...and even more data */
  err = tcp_write(pcb, data5, sizeof(data5), TCP_WRITE_FLAG_COPY);
  EXPECT_RET(err == ERR_OK);
  err = tcp_output(pcb);
  EXPECT_RET(err == ERR_OK);

#if 0
  /* create expected segment */
  p1 = tcp_create_rx_segment(pcb, counters.expected_data, data_len, 0, 0, 0);
  EXPECT_RET(p != NULL);
  if (p != NULL) {
    /* pass the segment to tcp_input */
    test_tcp_input(p, &netif);
    /* check if counters are as expected */
    EXPECT_RET(counters.close_calls == 0);
    EXPECT_RET(counters.recv_calls == 1);
    EXPECT_RET(counters.recved_bytes == data_len);
    EXPECT_RET(counters.err_calls == 0);
  }
#endif
  /* make sure the pcb is freed */
  EXPECT_RET(lwip_stats.memp[MEMP_TCP_PCB].used == 1);
  tcp_abort(pcb);
  EXPECT_RET(lwip_stats.memp[MEMP_TCP_PCB].used == 0);
}
Exemple #10
0
END_TEST

/** Check that we handle malformed tcp headers, and discard the pbuf(s) */
START_TEST(test_tcp_malformed_header)
{
  struct test_tcp_counters counters;
  struct tcp_pcb* pcb;
  struct pbuf* p;
  char data[] = {1, 2, 3, 4};
  ip_addr_t remote_ip, local_ip, netmask;
  u16_t data_len, chksum;
  u16_t remote_port = 0x100, local_port = 0x101;
  struct netif netif;
  struct test_tcp_txcounters txcounters;
  struct tcp_hdr *hdr;
  LWIP_UNUSED_ARG(_i);

  /* initialize local vars */
  memset(&netif, 0, sizeof(netif));
  IP_ADDR4(&local_ip, 192, 168, 1, 1);
  IP_ADDR4(&remote_ip, 192, 168, 1, 2);
  IP_ADDR4(&netmask,   255, 255, 255, 0);
  test_tcp_init_netif(&netif, &txcounters, &local_ip, &netmask);
  data_len = sizeof(data);
  /* initialize counter struct */
  memset(&counters, 0, sizeof(counters));
  counters.expected_data_len = data_len;
  counters.expected_data = data;

  /* create and initialize the pcb */
  pcb = test_tcp_new_counters_pcb(&counters);
  EXPECT_RET(pcb != NULL);
  tcp_set_state(pcb, ESTABLISHED, &local_ip, &remote_ip, local_port, remote_port);

  /* create a segment */
  p = tcp_create_rx_segment(pcb, counters.expected_data, data_len, 0, 0, 0);

  pbuf_header(p, -(s16_t)sizeof(struct ip_hdr));

  hdr = (struct tcp_hdr *)p->payload;
  TCPH_HDRLEN_FLAGS_SET(hdr, 15, 0x3d1);

  hdr->chksum = 0;

  chksum = ip_chksum_pseudo(p, IP_PROTO_TCP, p->tot_len,
                             &remote_ip, &local_ip);

  hdr->chksum = chksum;

  pbuf_header(p, sizeof(struct ip_hdr));

  EXPECT(p != NULL);
  EXPECT(p->next == NULL);
  if (p != NULL) {
    /* pass the segment to tcp_input */
    test_tcp_input(p, &netif);
    /* check if counters are as expected */
    EXPECT(counters.close_calls == 0);
    EXPECT(counters.recv_calls == 0);
    EXPECT(counters.recved_bytes == 0);
    EXPECT(counters.err_calls == 0);
  }

  /* make sure the pcb is freed */
  EXPECT(lwip_stats.memp[MEMP_TCP_PCB].used == 1);
  tcp_abort(pcb);
  EXPECT(lwip_stats.memp[MEMP_TCP_PCB].used == 0);
}
Exemple #11
0
END_TEST

START_TEST(test_tcp_rto_tracking)
{
  struct netif netif;
  struct test_tcp_txcounters txcounters;
  struct test_tcp_counters counters;
  struct tcp_pcb* pcb;
  struct pbuf* p;
  err_t err;
  size_t i;
  u16_t sent_total = 0;
  LWIP_UNUSED_ARG(_i);

  for (i = 0; i < sizeof(tx_data); i++) {
    tx_data[i] = (u8_t)i;
  }

  /* initialize local vars */
  test_tcp_init_netif(&netif, &txcounters, &test_local_ip, &test_netmask);
  memset(&counters, 0, sizeof(counters));

  /* create and initialize the pcb */
  tcp_ticks = SEQNO1 - ISS;
  pcb = test_tcp_new_counters_pcb(&counters);
  EXPECT_RET(pcb != NULL);
  tcp_set_state(pcb, ESTABLISHED, &test_local_ip, &test_remote_ip, TEST_LOCAL_PORT, TEST_REMOTE_PORT);
  pcb->mss = TCP_MSS;
  /* Set congestion window large enough to send all our segments */
  pcb->cwnd = 5*TCP_MSS;

  /* send 5 mss-sized segments */
  for (i = 0; i < 5; i++) {
    err = tcp_write(pcb, &tx_data[sent_total], TCP_MSS, TCP_WRITE_FLAG_COPY);
    EXPECT_RET(err == ERR_OK);
    sent_total += TCP_MSS;
  }
  check_seqnos(pcb->unsent, 5, seqnos);
  EXPECT(pcb->unacked == NULL);
  err = tcp_output(pcb);
  EXPECT(txcounters.num_tx_calls == 5);
  EXPECT(txcounters.num_tx_bytes == 5 * (TCP_MSS + 40U));
  memset(&txcounters, 0, sizeof(txcounters));
  /* Check all 5 are in-flight */
  EXPECT(pcb->unsent == NULL);
  check_seqnos(pcb->unacked, 5, seqnos);

  /* Force us into retransmisson timeout */
  while (!(pcb->flags & TF_RTO)) {
    test_tcp_tmr();
  }
  /* Ensure 4 remaining segments are back on unsent, ready for retransmission */
  check_seqnos(pcb->unsent, 4, &seqnos[1]);
  /* Ensure 1st segment is on unacked (already retransmitted) */
  check_seqnos(pcb->unacked, 1, seqnos);
  EXPECT(txcounters.num_tx_calls == 1);
  EXPECT(txcounters.num_tx_bytes == TCP_MSS + 40U);
  memset(&txcounters, 0, sizeof(txcounters));
  /* Ensure rto_end points to next byte */
  EXPECT(pcb->rto_end == seqnos[5]);
  EXPECT(pcb->rto_end == pcb->snd_nxt);
  /* Check cwnd was reset */
  EXPECT(pcb->cwnd == pcb->mss);

  /* Add another segment to send buffer which is outside of RTO */
  err = tcp_write(pcb, &tx_data[sent_total], TCP_MSS, TCP_WRITE_FLAG_COPY);
  EXPECT_RET(err == ERR_OK);
  sent_total += TCP_MSS;
  check_seqnos(pcb->unsent, 5, &seqnos[1]);
  /* Ensure no new data was sent */
  EXPECT(txcounters.num_tx_calls == 0);
  EXPECT(txcounters.num_tx_bytes == 0);
  EXPECT(pcb->rto_end == pcb->snd_nxt);

  /* ACK first segment */
  p = tcp_create_rx_segment(pcb, NULL, 0, 0, TCP_MSS, TCP_ACK);
  test_tcp_input(p, &netif);
  /* Next two retranmissions should go out, due to cwnd in slow start */
  EXPECT(txcounters.num_tx_calls == 2);
  EXPECT(txcounters.num_tx_bytes == 2 * (TCP_MSS + 40U));
  memset(&txcounters, 0, sizeof(txcounters));
  check_seqnos(pcb->unacked, 2, &seqnos[1]);
  check_seqnos(pcb->unsent, 3, &seqnos[3]);
  /* RTO should still be marked */
  EXPECT(pcb->flags & TF_RTO);
  /* cwnd should have only grown by 1 MSS */
  EXPECT(pcb->cwnd == (tcpwnd_size_t)(2 * pcb->mss));
  /* Ensure no new data was sent */
  EXPECT(pcb->rto_end == pcb->snd_nxt);

  /* ACK the next two segments */
  p = tcp_create_rx_segment(pcb, NULL, 0, 0, 2*TCP_MSS, TCP_ACK);
  test_tcp_input(p, &netif);
  /* Final 2 retransmissions and 1 new data should go out */
  EXPECT(txcounters.num_tx_calls == 3);
  EXPECT(txcounters.num_tx_bytes == 3 * (TCP_MSS + 40U));
  memset(&txcounters, 0, sizeof(txcounters));
  check_seqnos(pcb->unacked, 3, &seqnos[3]);
  EXPECT(pcb->unsent == NULL);
  /* RTO should still be marked */
  EXPECT(pcb->flags & TF_RTO);
  /* cwnd should have only grown by 1 MSS */
  EXPECT(pcb->cwnd == (tcpwnd_size_t)(3 * pcb->mss));
  /* snd_nxt should have been advanced past rto_end */
  EXPECT(TCP_SEQ_GT(pcb->snd_nxt, pcb->rto_end));

  /* ACK the next two segments, finishing our RTO, leaving new segment unacked */
  p = tcp_create_rx_segment(pcb, NULL, 0, 0, 2*TCP_MSS, TCP_ACK);
  test_tcp_input(p, &netif);
  EXPECT(!(pcb->flags & TF_RTO));
  check_seqnos(pcb->unacked, 1, &seqnos[5]);
  /* We should be in ABC congestion avoidance, so no change in cwnd */
  EXPECT(pcb->cwnd == (tcpwnd_size_t)(3 * pcb->mss));
  EXPECT(pcb->cwnd >= pcb->ssthresh);
  /* Ensure ABC congestion avoidance is tracking bytes acked */
  EXPECT(pcb->bytes_acked == (tcpwnd_size_t)(2 * pcb->mss));

  /* make sure the pcb is freed */
  EXPECT_RET(MEMP_STATS_GET(used, MEMP_TCP_PCB) == 1);
  tcp_abort(pcb);
  EXPECT_RET(MEMP_STATS_GET(used, MEMP_TCP_PCB) == 0);
}