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Fix endianness of default DHCP offer netmask #56

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Merged
philljj merged 4 commits into from
Mar 2, 2026
Merged

Fix endianness of default DHCP offer netmask #56

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318b501
Fix endianness of default DHCP offer netmask
danielinux Mar 2, 2026
0893af6
Added comment
danielinux Mar 2, 2026
03ba436
Moved default netmask into a define
danielinux Mar 2, 2026
8a81ff8
Fix typo in comment
danielinux Mar 2, 2026
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41 changes: 41 additions & 0 deletions src/test/unit/unit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4328,6 +4328,46 @@ START_TEST(test_dhcp_parse_offer_and_ack)
}
END_TEST

START_TEST(test_dhcp_parse_offer_defaults_mask_when_missing)
{
struct wolfIP s;
struct dhcp_msg msg;
struct dhcp_option *opt;
struct ipconf *primary;
uint32_t offer_ip = 0x0A000064U;
uint32_t server_ip = 0x0A000001U;
uint32_t mask = 0xFFFFFF00U;

wolfIP_init(&s);
primary = wolfIP_primary_ipconf(&s);
ck_assert_ptr_nonnull(primary);

memset(&msg, 0, sizeof(msg));
msg.magic = ee32(DHCP_MAGIC);
msg.yiaddr = ee32(offer_ip);
opt = (struct dhcp_option *)msg.options;
opt->code = DHCP_OPTION_MSG_TYPE;
opt->len = 1;
opt->data[0] = DHCP_OFFER;
opt = (struct dhcp_option *)((uint8_t *)opt + 3);
opt->code = DHCP_OPTION_SERVER_ID;
opt->len = 4;
opt->data[0] = (server_ip >> 24) & 0xFF;
opt->data[1] = (server_ip >> 16) & 0xFF;
opt->data[2] = (server_ip >> 8) & 0xFF;
opt->data[3] = (server_ip >> 0) & 0xFF;
opt = (struct dhcp_option *)((uint8_t *)opt + 6);
opt->code = DHCP_OPTION_END;
opt->len = 0;

ck_assert_int_eq(dhcp_parse_offer(&s, &msg, sizeof(msg)), 0);
ck_assert_uint_eq(s.dhcp_ip, offer_ip);
ck_assert_uint_eq(s.dhcp_server_ip, server_ip);
ck_assert_uint_eq(primary->mask, mask);
ck_assert_int_eq(s.dhcp_state, DHCP_REQUEST_SENT);
}
END_TEST

START_TEST(test_sock_recvfrom_tcp_states)
{
struct wolfIP s;
Expand Down Expand Up @@ -17499,6 +17539,7 @@ Suite *wolf_suite(void)
tcase_add_test(tc_proto, test_udp_recvfrom_src_equals_local_ip_does_not_persist_remote);
tcase_add_test(tc_proto, test_dns_query_and_callback_a);
tcase_add_test(tc_proto, test_dhcp_parse_offer_and_ack);
tcase_add_test(tc_proto, test_dhcp_parse_offer_defaults_mask_when_missing);
tcase_add_test(tc_proto, test_tcp_handshake_and_fin_close_wait);

tcase_add_test(tc_proto, test_regression_snd_una_initialized_on_syn_rcvd);
Expand Down
8 changes: 7 additions & 1 deletion src/wolfip.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4646,13 +4646,19 @@ static void dhcp_cancel_timer(struct wolfIP *s)
(opt)->data[3] = ((v) >> 0) & 0xFF; \
} while (0)

/* Default netmask (returned if the offer does not deliver one)
* must be in network order (same order as DHCP_OPT_data_to_u32 on the field,
* if present).
*/
#define DHCP_DEFAULT_24BIT_NETMASK (0x00FFFFFFu)

static int dhcp_parse_offer(struct wolfIP *s, struct dhcp_msg *msg, uint32_t msg_len)
{
uint8_t *opt = (uint8_t *)msg->options;
uint8_t *opt_end;
int saw_end = 0;
uint32_t ip;
uint32_t netmask = 0xFFFFFF00;
uint32_t netmask = DHCP_DEFAULT_24BIT_NETMASK;
struct ipconf *primary = wolfIP_primary_ipconf(s);
if (msg_len < DHCP_HEADER_LEN)
return -1;
Expand Down