menu "LWIP" config L2_TO_L3_COPY bool "Enable copy between Layer2 and Layer3 packets" default n help If this feature is enabled, all traffic from layer2(WIFI Driver) will be copied to a new buffer before sending it to layer3(LWIP stack), freeing the layer2 buffer. Please be notified that the total layer2 receiving buffer is fixed and ESP32 currently supports 25 layer2 receiving buffer, when layer2 buffer runs out of memory, then the incoming packets will be dropped in hardware. The layer3 buffer is allocated from the heap, so the total layer3 receiving buffer depends on the available heap size, when heap runs out of memory, no copy will be sent to layer3 and packet will be dropped in layer2. Please make sure you fully understand the impact of this feature before enabling it. config LWIP_IRAM_OPTIMIZATION bool "Enable LWIP IRAM optimization" default n help If this feature is enabled, some functions relating to RX/TX in LWIP will be put into IRAM, it can improve UDP/TCP throughput by >10% for single core mode, it doesn't help too much for dual core mode. On the other hand, it needs about 10KB IRAM for these optimizations. If this feature is disabled, all lwip functions will be put into FLASH. config LWIP_MAX_SOCKETS int "Max number of open sockets" range 1 16 default 10 help Sockets take up a certain amount of memory, and allowing fewer sockets to be open at the same time conserves memory. Specify the maximum amount of sockets here. The valid value is from 1 to 16. config LWIP_RANDOMIZE_INITIAL_LOCAL_PORTS bool "Randomize the local port for the first" default y help LWIP_RANDOMIZE_INITIAL_LOCAL_PORTS==1: randomize the local port for the first local TCP/UDP pcb (default==0). This can prevent creating predictable port numbers after booting a device. config USE_ONLY_LWIP_SELECT bool "Support LWIP socket select() only" default n help The virtual filesystem layer of select() redirects sockets to lwip_select() and non-socket file descriptors to their respective driver implementations. If this option is enabled then all calls of select() will be redirected to lwip_select(), therefore, select can be used for sockets only. config LWIP_SO_LINGER bool "Enable SO_LINGER processing" default n help Enabling this option allows SO_LINGER processing. l_onoff = 1,l_linger can set the timeout. If l_linger=0, When a connection is closed, TCP will terminate the connection. This means that TCP will discard any data packets stored in the socket send buffer and send an RST to the peer. If l_linger!=0,Then closesocket() calls to block the process until the remaining data packets has been sent or timed out. config LWIP_SO_REUSE bool "Enable SO_REUSEADDR option" default y help Enabling this option allows binding to a port which remains in TIME_WAIT. config LWIP_SO_REUSE_RXTOALL bool "SO_REUSEADDR copies broadcast/multicast to all matches" depends on LWIP_SO_REUSE default y help Enabling this option means that any incoming broadcast or multicast packet will be copied to all of the local sockets that it matches (may be more than one if SO_REUSEADDR is set on the socket.) This increases memory overhead as the packets need to be copied, however they are only copied per matching socket. You can safely disable it if you don't plan to receive broadcast or multicast traffic on more than one socket at a time. config LWIP_SO_RCVBUF bool "Enable SO_RCVBUF option" default n help Enabling this option allows checking for available data on a netconn. config LWIP_DHCP_MAX_NTP_SERVERS int "Maximum number of NTP servers" default 1 range 1 16 help Set maximum number of NTP servers used by LwIP SNTP module. First argument of sntp_setserver/sntp_setservername functions is limited to this value. config LWIP_IP4_FRAG bool "Enable fragment outgoing IP4 packets" default y help Enabling this option allows fragmenting outgoing IP4 packets if their size exceeds MTU. config LWIP_IP6_FRAG bool "Enable fragment outgoing IP6 packets" default y help Enabling this option allows fragmenting outgoing IP6 packets if their size exceeds MTU. config LWIP_IP4_REASSEMBLY bool "Enable reassembly incoming fragmented IP4 packets" default n help Enabling this option allows reassemblying incoming fragmented IP4 packets. config LWIP_IP6_REASSEMBLY bool "Enable reassembly incoming fragmented IP6 packets" default n help Enabling this option allows reassemblying incoming fragmented IP6 packets. config LWIP_STATS bool "Enable LWIP statistics" default n help Enabling this option allows LWIP statistics config LWIP_ETHARP_TRUST_IP_MAC bool "Enable LWIP ARP trust" default n help Enabling this option allows ARP table to be updated. If this option is enabled, the incoming IP packets cause the ARP table to be updated with the source MAC and IP addresses supplied in the packet. You may want to disable this if you do not trust LAN peers to have the correct addresses, or as a limited approach to attempt to handle spoofing. If disabled, lwIP will need to make a new ARP request if the peer is not already in the ARP table, adding a little latency. The peer *is* in the ARP table if it requested our address before. Also notice that this slows down input processing of every IP packet! There are two known issues in real application if this feature is enabled: - The LAN peer may have bug to update the ARP table after the ARP entry is aged out. If the ARP entry on the LAN peer is aged out but failed to be updated, all IP packets sent from LWIP to the LAN peer will be dropped by LAN peer. - The LAN peer may not be trustful, the LAN peer may send IP packets to LWIP with two different MACs, but the same IP address. If this happens, the LWIP has problem to receive IP packets from LAN peer. So the recommendation is to disable this option. Here the LAN peer means the other side to which the ESP station or soft-AP is connected. config ESP_GRATUITOUS_ARP bool "Send gratuitous ARP periodically" default y help Enable this option allows to send gratuitous ARP periodically. This option solve the compatibility issues.If the ARP table of the AP is old, and the AP doesn't send ARP request to update it's ARP table, this will lead to the STA sending IP packet fail. Thus we send gratuitous ARP periodically to let AP update it's ARP table. config GARP_TMR_INTERVAL int "GARP timer interval(seconds)" default 60 depends on ESP_GRATUITOUS_ARP help Set the timer interval for gratuitous ARP. The default value is 60s config TCPIP_RECVMBOX_SIZE int "TCPIP task receive mail box size" default 32 range 6 64 if !LWIP_WND_SCALE range 6 1024 if LWIP_WND_SCALE help Set TCPIP task receive mail box size. Generally bigger value means higher throughput but more memory. The value should be bigger than UDP/TCP mail box size. config LWIP_DHCP_DOES_ARP_CHECK bool "DHCP: Perform ARP check on any offered address" default y help Enabling this option performs a check (via ARP request) if the offered IP address is not already in use by another host on the network. config LWIP_DHCP_RESTORE_LAST_IP bool "DHCP: Restore last IP obtained from DHCP server" default n help When this option is enabled, DHCP client tries to re-obtain last valid IP address obtained from DHCP server. Last valid DHCP configuration is stored in nvs and restored after reset/power-up. If IP is still available, there is no need for sending discovery message to DHCP server and save some time. menu "DHCP server" config LWIP_DHCPS_LEASE_UNIT int "Multiplier for lease time, in seconds" range 1 3600 default 60 help The DHCP server is calculating lease time multiplying the sent and received times by this number of seconds per unit. The default is 60, that equals one minute. config LWIP_DHCPS_MAX_STATION_NUM int "Maximum number of stations" range 1 64 default 8 help The maximum number of DHCP clients that are connected to the server. After this number is exceeded, DHCP server removes of the oldest device from it's address pool, without notification. endmenu # DHCPS menuconfig LWIP_AUTOIP bool "Enable IPV4 Link-Local Addressing (AUTOIP)" default n help Enabling this option allows the device to self-assign an address in the 169.256/16 range if none is assigned statically or via DHCP. See RFC 3927. config LWIP_AUTOIP_TRIES int "DHCP Probes before self-assigning IPv4 LL address" range 1 100 default 2 depends on LWIP_AUTOIP help DHCP client will send this many probes before self-assigning a link local address. From LWIP help: "This can be set as low as 1 to get an AutoIP address very quickly, but you should be prepared to handle a changing IP address when DHCP overrides AutoIP." (In the case of ESP-IDF, this means multiple SYSTEM_EVENT_STA_GOT_IP events.) config LWIP_AUTOIP_MAX_CONFLICTS int "Max IP conflicts before rate limiting" range 1 100 default 9 depends on LWIP_AUTOIP help If the AUTOIP functionality detects this many IP conflicts while self-assigning an address, it will go into a rate limited mode. config LWIP_AUTOIP_RATE_LIMIT_INTERVAL int "Rate limited interval (seconds)" range 5 120 default 20 depends on LWIP_AUTOIP help If rate limiting self-assignment requests, wait this long between each request. config LWIP_IPV6_AUTOCONFIG bool "Enable IPV6 stateless address autoconfiguration" default n help Enabling this option allows the devices to IPV6 stateless address autoconfiguration. See RFC 4862. menuconfig LWIP_NETIF_LOOPBACK bool "Support per-interface loopback" default y help Enabling this option means that if a packet is sent with a destination address equal to the interface's own IP address, it will "loop back" and be received by this interface. config LWIP_LOOPBACK_MAX_PBUFS int "Max queued loopback packets per interface" range 0 16 default 8 depends on LWIP_NETIF_LOOPBACK help Configure the maximum number of packets which can be queued for loopback on a given interface. Reducing this number may cause packets to be dropped, but will avoid filling memory with queued packet data. menu "TCP" config LWIP_MAX_ACTIVE_TCP int "Maximum active TCP Connections" range 1 1024 default 16 help The maximum number of simultaneously active TCP connections. The practical maximum limit is determined by available heap memory at runtime. Changing this value by itself does not substantially change the memory usage of LWIP, except for preventing new TCP connections after the limit is reached. config LWIP_MAX_LISTENING_TCP int "Maximum listening TCP Connections" range 1 1024 default 16 help The maximum number of simultaneously listening TCP connections. The practical maximum limit is determined by available heap memory at runtime. Changing this value by itself does not substantially change the memory usage of LWIP, except for preventing new listening TCP connections after the limit is reached. config TCP_MAXRTX int "Maximum number of retransmissions of data segments" default 12 range 3 12 help Set maximum number of retransmissions of data segments. config TCP_SYNMAXRTX int "Maximum number of retransmissions of SYN segments" default 6 range 3 12 help Set maximum number of retransmissions of SYN segments. config TCP_MSS int "Maximum Segment Size (MSS)" default 1440 range 536 1440 help Set maximum segment size for TCP transmission. Can be set lower to save RAM, the default value 1460(ipv4)/1440(ipv6) will give best throughput. IPv4 TCP_MSS Range: 576 <= TCP_MSS <= 1460 IPv6 TCP_MSS Range: 1220<= TCP_MSS <= 1440 config TCP_MSL int "Maximum segment lifetime (MSL)" default 60000 help Set maximum segment lifetime in in milliseconds. config TCP_SND_BUF_DEFAULT int "Default send buffer size" default 5744 # 4 * default MSS range 2440 65535 help Set default send buffer size for new TCP sockets. Per-socket send buffer size can be changed at runtime with lwip_setsockopt(s, TCP_SNDBUF, ...). This value must be at least 2x the MSS size, and the default is 4x the default MSS size. Setting a smaller default SNDBUF size can save some RAM, but will decrease performance. config TCP_WND_DEFAULT int "Default receive window size" default 5744 # 4 * default MSS range 2440 65535 help Set default TCP receive window size for new TCP sockets. Per-socket receive window size can be changed at runtime with lwip_setsockopt(s, TCP_WINDOW, ...). Setting a smaller default receive window size can save some RAM, but will significantly decrease performance. config TCP_RECVMBOX_SIZE int "Default TCP receive mail box size" default 6 range 6 64 if !LWIP_WND_SCALE range 6 1024 if LWIP_WND_SCALE help Set TCP receive mail box size. Generally bigger value means higher throughput but more memory. The recommended value is: TCP_WND_DEFAULT/TCP_MSS + 2, e.g. if TCP_WND_DEFAULT=14360, TCP_MSS=1436, then the recommended receive mail box size is (14360/1436 + 2) = 12. TCP receive mail box is a per socket mail box, when the application receives packets from TCP socket, LWIP core firstly posts the packets to TCP receive mail box and the application then fetches the packets from mail box. It means LWIP can caches maximum TCP_RECCVMBOX_SIZE packets for each TCP socket, so the maximum possible cached TCP packets for all TCP sockets is TCP_RECCVMBOX_SIZE multiples the maximum TCP socket number. In other words, the bigger TCP_RECVMBOX_SIZE means more memory. On the other hand, if the receiv mail box is too small, the mail box may be full. If the mail box is full, the LWIP drops the packets. So generally we need to make sure the TCP receive mail box is big enough to avoid packet drop between LWIP core and application. config TCP_QUEUE_OOSEQ bool "Queue incoming out-of-order segments" default y help Queue incoming out-of-order segments for later use. Disable this option to save some RAM during TCP sessions, at the expense of increased retransmissions if segments arrive out of order. config ESP_TCP_KEEP_CONNECTION_WHEN_IP_CHANGES bool "Keep TCP connections when IP changed" default n help This option is enabled when the following scenario happen: network dropped and reconnected, IP changes is like: 192.168.0.2->0.0.0.0->192.168.0.2 Disable this option to keep consistent with the original LWIP code behavior. choice TCP_OVERSIZE prompt "Pre-allocate transmit PBUF size" default TCP_OVERSIZE_MSS help Allows enabling "oversize" allocation of TCP transmission pbufs ahead of time, which can reduce the length of pbuf chains used for transmission. This will not make a difference to sockets where Nagle's algorithm is disabled. Default value of MSS is fine for most applications, 25% MSS may save some RAM when only transmitting small amounts of data. Disabled will have worst performance and fragmentation characteristics, but uses least RAM overall. config TCP_OVERSIZE_MSS bool "MSS" config TCP_OVERSIZE_QUARTER_MSS bool "25% MSS" config TCP_OVERSIZE_DISABLE bool "Disabled" endchoice config LWIP_WND_SCALE bool "Support TCP window scale" depends on WIFI_LWIP_ALLOCATION_FROM_SPIRAM_FIRST default n help Enable this feature to support TCP window scaling. config TCP_RCV_SCALE int "Set TCP receiving window scaling factor" depends on LWIP_WND_SCALE range 0 14 default 0 help Enable this feature to support TCP window scaling. config LWIP_TCP_RTO_TIME int "Default TCP rto time" default 3000 help Set default TCP rto time for a reasonable initial rto. In bad network environment, recommend set value of rto time to 1500. endmenu # TCP menu "UDP" config LWIP_MAX_UDP_PCBS int "Maximum active UDP control blocks" range 1 1024 default 16 help The maximum number of active UDP "connections" (ie UDP sockets sending/receiving data). The practical maximum limit is determined by available heap memory at runtime. config UDP_RECVMBOX_SIZE int "Default UDP receive mail box size" default 6 range 6 64 help Set UDP receive mail box size. The recommended value is 6. UDP receive mail box is a per socket mail box, when the application receives packets from UDP socket, LWIP core firstly posts the packets to UDP receive mail box and the application then fetches the packets from mail box. It means LWIP can caches maximum UDP_RECCVMBOX_SIZE packets for each UDP socket, so the maximum possible cached UDP packets for all UDP sockets is UDP_RECCVMBOX_SIZE multiples the maximum UDP socket number. In other words, the bigger UDP_RECVMBOX_SIZE means more memory. On the other hand, if the receiv mail box is too small, the mail box may be full. If the mail box is full, the LWIP drops the packets. So generally we need to make sure the UDP receive mail box is big enough to avoid packet drop between LWIP core and application. endmenu # UDP config TCPIP_TASK_STACK_SIZE int "TCP/IP Task Stack Size" default 3072 # for high log levels, tcpip_adapter API calls can end up # a few calls deep and logging there can trigger a stack overflow range 2048 65536 if LOG_DEFAULT_LEVEL < 4 range 2560 65536 if LOG_DEFAULT_LEVEL >= 4 help Configure TCP/IP task stack size, used by LWIP to process multi-threaded TCP/IP operations. Setting this stack too small will result in stack overflow crashes. choice TCPIP_TASK_AFFINITY prompt "TCP/IP task affinity" default TCPIP_TASK_AFFINITY_NO_AFFINITY help Allows setting LwIP tasks affinity, i.e. whether the task is pinned to CPU0, pinned to CPU1, or allowed to run on any CPU. Currently this applies to "TCP/IP" task and "Ping" task. config TCPIP_TASK_AFFINITY_NO_AFFINITY bool "No affinity" config TCPIP_TASK_AFFINITY_CPU0 bool "CPU0" config TCPIP_TASK_AFFINITY_CPU1 bool "CPU1" depends on !FREERTOS_UNICORE endchoice config TCPIP_TASK_AFFINITY hex default FREERTOS_NO_AFFINITY if TCPIP_TASK_AFFINITY_NO_AFFINITY default 0x0 if TCPIP_TASK_AFFINITY_CPU0 default 0x1 if TCPIP_TASK_AFFINITY_CPU1 menuconfig PPP_SUPPORT bool "Enable PPP support (new/experimental)" default n help Enable PPP stack. Now only PPP over serial is possible. PPP over serial support is experimental and unsupported. config PPP_PAP_SUPPORT bool "Enable PAP support" depends on PPP_SUPPORT default n help Enable Password Authentication Protocol (PAP) support config PPP_CHAP_SUPPORT bool "Enable CHAP support" depends on PPP_SUPPORT default n help Enable Challenge Handshake Authentication Protocol (CHAP) support config PPP_MSCHAP_SUPPORT bool "Enable MSCHAP support" depends on PPP_SUPPORT default n help Enable Microsoft version of the Challenge-Handshake Authentication Protocol (MSCHAP) support config PPP_MPPE_SUPPORT bool "Enable MPPE support" depends on PPP_SUPPORT default n help Enable Microsoft Point-to-Point Encryption (MPPE) support config PPP_DEBUG_ON bool "Enable PPP debug log output" depends on PPP_SUPPORT default n help Enable PPP debug log output menu "ICMP" config LWIP_MULTICAST_PING bool "Respond to multicast pings" default n config LWIP_BROADCAST_PING bool "Respond to broadcast pings" default n endmenu # ICMP menu "LWIP RAW API" config LWIP_MAX_RAW_PCBS int "Maximum LWIP RAW PCBs" range 1 1024 default 16 help The maximum number of simultaneously active LWIP RAW protocol control blocks. The practical maximum limit is determined by available heap memory at runtime. endmenu # LWIP RAW API endmenu