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Merge branch 'bugfix/fix_dhcp_server_address_pool_issue' into 'master'
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fix(dhcp server): Fix dhcp server address pool issue

Closes IDF-7316

See merge request espressif/esp-idf!24818
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@jack0c
jack0c committed Jul 26, 2023
2 parents 8eaa598 + 15be9a0 commit f7ef577
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Showing 2 changed files with 42 additions and 22 deletions.
56 changes: 34 additions & 22 deletions components/lwip/apps/dhcpserver/dhcpserver.c
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* SPDX-FileCopyrightText: 2015-2022 Espressif Systems (Shanghai) CO LTD
* SPDX-FileCopyrightText: 2015-2023 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
Expand Down Expand Up @@ -76,6 +76,18 @@
} \
} while (0)

#define DHCP_CHECK_IP_MATCH_SUBNET_MASK(mask, ip) \
u32_t start_ip = 0; \
u32_t end_ip = 0; \
do { \
start_ip = ip & mask; \
end_ip = start_ip | ~mask; \
if (ip == end_ip || ip == start_ip) { \
DHCPS_LOG("dhcps: ip address and subnet mask do not match.\n"); \
return ERR_ARG; \
} \
} while (0)

#define MAX_STATION_NUM CONFIG_LWIP_DHCPS_MAX_STATION_NUM

#define DHCPS_STATE_OFFER 1
Expand Down Expand Up @@ -1154,11 +1166,11 @@ static void handle_dhcp(void *arg,
*******************************************************************************/
static void dhcps_poll_set(dhcps_t *dhcps, u32_t ip)
{
u32_t server_ip = 0, local_ip = 0;
u32_t server_ip = 0;
u32_t start_ip = 0;
u32_t end_ip = 0;
u32_t temp_local_ip = 0;
u32_t host_num = 0;
u32_t range_start_ip = 0;
u32_t range_end_ip = 0;
dhcps_lease_t *dhcps_poll = &dhcps->dhcps_poll;
if (dhcps_poll->enable == true) {
server_ip = htonl(ip);
Expand All @@ -1170,34 +1182,33 @@ static void dhcps_poll_set(dhcps_t *dhcps, u32_t ip)
dhcps_poll->enable = false;
} else {
/*config ip information must be in the same segment as the local ip*/
server_ip >>= 8;

if (((start_ip >> 8 != server_ip) || (end_ip >> 8 != server_ip))
|| (end_ip - start_ip > DHCPS_MAX_LEASE)) {
if (!ip4_addr_netcmp(&dhcps_poll->start_ip, &dhcps->server_address, &dhcps->dhcps_mask)
|| !ip4_addr_netcmp(&dhcps_poll->end_ip, &dhcps->server_address, &dhcps->dhcps_mask)
|| (end_ip - start_ip + 1 > DHCPS_MAX_LEASE)) {
dhcps_poll->enable = false;
}
}
}

if (dhcps_poll->enable == false) {
local_ip = server_ip = htonl(ip);
server_ip &= 0xFFFFFF00;
temp_local_ip = local_ip &= 0xFF;
server_ip = htonl(ip);
range_start_ip = server_ip & htonl(dhcps->dhcps_mask.addr);
range_end_ip = range_start_ip | ~htonl(dhcps->dhcps_mask.addr);

if (local_ip >= 0x80) {
local_ip -= DHCPS_MAX_LEASE;
temp_local_ip -= DHCPS_MAX_LEASE;
if (server_ip - range_start_ip > range_end_ip - server_ip) {
range_start_ip = range_start_ip + 1;
range_end_ip = server_ip - 1;
} else {
local_ip ++;
range_start_ip = server_ip + 1;
range_end_ip = range_end_ip - 1;
}

bzero(dhcps_poll, sizeof(*dhcps_poll));
host_num = IP_CLASS_HOST_NUM(htonl(dhcps->dhcps_mask.addr));
if (host_num > DHCPS_MAX_LEASE) {
host_num = DHCPS_MAX_LEASE;
if (range_end_ip - range_start_ip + 1 > DHCPS_MAX_LEASE) {
range_end_ip = range_start_ip + DHCPS_MAX_LEASE - 1;
}
dhcps_poll->start_ip.addr = server_ip | local_ip;
dhcps_poll->end_ip.addr = server_ip | (temp_local_ip + host_num - 1);
bzero(dhcps_poll, sizeof(*dhcps_poll));
dhcps_poll->start_ip.addr = range_start_ip;
dhcps_poll->end_ip.addr = range_end_ip;
dhcps_poll->start_ip.addr = htonl(dhcps_poll->start_ip.addr);
dhcps_poll->end_ip.addr = htonl(dhcps_poll->end_ip.addr);
}
Expand Down Expand Up @@ -1242,14 +1253,15 @@ err_t dhcps_start(dhcps_t *dhcps, struct netif *netif, ip4_addr_t ip)
dhcps->dhcps_pcb = udp_new();

if (dhcps->dhcps_pcb == NULL || ip4_addr_isany_val(ip)) {
printf("dhcps_start(): could not obtain pcb\n");
DHCPS_LOG("dhcps_start(): could not obtain pcb\n");
return ERR_ARG;
}

IP4_ADDR(&dhcps->broadcast_dhcps, 255, 255, 255, 255);

dhcps->server_address.addr = ip.addr;
DHCP_CHECK_SUBNET_MASK_IP(htonl(dhcps->dhcps_mask.addr));
DHCP_CHECK_IP_MATCH_SUBNET_MASK(htonl(dhcps->dhcps_mask.addr), htonl(ip.addr));
dhcps_poll_set(dhcps, dhcps->server_address.addr);

dhcps->client_address_plus.addr = dhcps->dhcps_poll.start_ip.addr;
Expand Down
8 changes: 8 additions & 0 deletions components/lwip/test_apps/main/lwip_test.c
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Original file line number Diff line number Diff line change
Expand Up @@ -205,11 +205,19 @@ TEST(lwip, dhcp_server_start_stop_localhost)
// Class C: IP: 192.168.1.1, Mask: 255.255.255.0
dhcps_test_net_classes(0xC0A80101, 0xFFFFFF00, true);

// Class C: IP: 192.168.4.1, Mask: 255.255.0.0
dhcps_test_net_classes(0xC0A80401, 0xFFFF0000, true);

// Class C: IP: 192.168.4.1, Mask: 255.0.0.0
dhcps_test_net_classes(0xC0A80401, 0xFF000000, true);

// Class A: IP: 127.0.0.1, with inaccurate Mask: 255.248.255.0
// expect dhcps_start() to fail
dhcps_test_net_classes(0x7f000001, 0xFFF8FF00, false);

// Class C: IP: 192.168.200.8, with inaccurate Mask: 255.255.255.248
// expect dhcps_start() to fail
dhcps_test_net_classes(0xC0A8C808, 0xFFFFFFF8, false);
}


Expand Down

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