Fix regression in tcp_tx_desc_ip_len for non-ethernet devices

Author: danielinux

src/test/unit/unit.c

@@ -750,7 +750,7 @@ Suite *wolf_suite(void)
     tcase_add_test(tc_proto, test_regression_syn_on_last_ack_not_silently_processed);
     tcase_add_test(tc_proto, test_regression_full_txbuf_still_sends_pure_ack);
     tcase_add_test(tc_proto, test_regression_loopback_immediate_pure_ack_uses_loopback_ll);
-    tcase_add_test(tc_proto, test_regression_tcp_tx_desc_payload_len_uses_link_type_not_length_heuristic);
+    tcase_add_test(tc_proto, test_regression_tcp_tx_desc_payload_len_keeps_descriptor_layout_sanity);
     tcase_add_test(tc_proto, test_regression_fast_recovery_cwnd_ssthresh_rfc5681);
     tcase_add_test(tc_proto, test_regression_paws_rejects_stale_timestamp);
     tcase_add_test(tc_proto, test_regression_paws_accepts_wrapped_newer_timestamp);

src/test/unit/unit_tests_proto.c

@@ -4800,7 +4800,7 @@ START_TEST(test_regression_loopback_immediate_pure_ack_uses_loopback_ll)
 }
 END_TEST
 
-START_TEST(test_regression_tcp_tx_desc_payload_len_uses_link_type_not_length_heuristic)
+START_TEST(test_regression_tcp_tx_desc_payload_len_keeps_descriptor_layout_sanity)
 {
     struct wolfIP s;
     struct tsocket *ts;
@@ -4827,10 +4827,22 @@ START_TEST(test_regression_tcp_tx_desc_payload_len_uses_link_type_not_length_heu
     ck_assert_uint_eq(tcp_tx_desc_ip_len(ts, &desc, &seg), 0U);
     ck_assert_uint_eq(tcp_tx_desc_payload_len(ts, &desc, &seg), 0U);
 
-    /* The same descriptor length is valid on non-Ethernet/L3 links. */
+    /* Non-Ethernet links still use the same queued descriptor layout. */
+    s.ll_dev[TEST_PRIMARY_IF].non_ethernet = 1;
+    ck_assert_uint_eq(tcp_tx_desc_ip_len(ts, &desc, &seg), 0U);
+    ck_assert_uint_eq(tcp_tx_desc_payload_len(ts, &desc, &seg), 0U);
+
+    /* Once the descriptor includes stored link headroom, both paths decode
+     * the same IP and payload lengths. */
+    desc.len = ETH_HEADER_LEN + IP_HEADER_LEN + TCP_HEADER_LEN + 4;
+    s.ll_dev[TEST_PRIMARY_IF].non_ethernet = 0;
+    ck_assert_uint_eq(tcp_tx_desc_ip_len(ts, &desc, &seg),
+            IP_HEADER_LEN + TCP_HEADER_LEN + 4U);
+    ck_assert_uint_eq(tcp_tx_desc_payload_len(ts, &desc, &seg), 4U);
+
     s.ll_dev[TEST_PRIMARY_IF].non_ethernet = 1;
     ck_assert_uint_eq(tcp_tx_desc_ip_len(ts, &desc, &seg),
-            (uint32_t)desc.len);
+            IP_HEADER_LEN + TCP_HEADER_LEN + 4U);
     ck_assert_uint_eq(tcp_tx_desc_payload_len(ts, &desc, &seg), 4U);
 }
 END_TEST

src/wolfip.c

@@ -2829,17 +2829,13 @@ static uint32_t tcp_tx_desc_ip_len(const struct tsocket *t,
 {
     uint32_t seg_ip_len;
     uint32_t seg_hdr_len;
-    unsigned int tx_if;
 
     if (!t || !desc || !seg)
         return 0;
     seg_hdr_len = IP_HEADER_LEN + (uint32_t)(seg->hlen >> 2);
     seg_ip_len = ee16(seg->ip.len);
     if (seg_ip_len != 0)
         return seg_ip_len;
-    tx_if = wolfIP_socket_if_idx(t);
-    if (wolfIP_ll_is_non_ethernet(t->S, tx_if))
-        return desc->len;
     if (desc->len < (ETH_HEADER_LEN + seg_hdr_len))
         return 0;
     return desc->len - ETH_HEADER_LEN;