ESP8266 lwIP Implementation

[AmeyAvhad]

Hey can anyone help me with how to set the IP_TOS value in MQTT messages in ESP8266. I need to change the IP_TOS value for my project but the lwip stack doesn't seems to have the support for it, if so how can I implement it in the source code.

[jimmo]

@AmeyAvhad LWIP does support TOS, but the MicroPython bindings do not.

You need to add handling for it to setsockopt, see https://github.com/micropython/micropython/blob/master/extmod/modlwip.c#L1374, to call lwip's setsockopt.

[AmeyAvhad]

Hey thanks for the reply, I am fairly new to it so can you just tell me one thing that do I need to make changes to any other files excluding modlwip.c for it to work. And if possible, provide a sample code to handle it.

Thanks Once Again.

[jimmo]

I think it should be just modlwip.c

[AmeyAvhad]

Hey @jimmo , can you help its not working I added the code for IP_TOS function

case IP_TOS:{
mp_int_t val = mp_obj_get_int(args[3]);
            socket->tos = val;
            break;
}

and edited the lwip object

typedef struct _lwip_socket_obj_t {
    mp_obj_base_t base;

    volatile union {
        struct tcp_pcb *tcp;
        struct udp_pcb *udp;
        struct raw_pcb *raw;
    } pcb;
    volatile union {
        struct pbuf *pbuf;
        struct {
            uint8_t alloc;
            uint8_t iget;
            uint8_t iput;
            union {
                struct tcp_pcb *item; // if alloc == 0
                struct tcp_pcb **array; // if alloc != 0
            } tcp;
        } connection;
    } incoming;
    mp_obj_t callback;
    byte peer[4];
    mp_uint_t peer_port;
    mp_uint_t timeout;
    uint16_t recv_offset;
    uint8_t tos;
    uint8_t domain;
    uint8_t type;

    #define STATE_NEW 0
    #define STATE_LISTENING 1
    #define STATE_CONNECTING 2
    #define STATE_CONNECTED 3
    #define STATE_PEER_CLOSED 4
    #define STATE_ACTIVE_UDP 5
    // Negative value is lwIP error
    int8_t state;
} lwip_socket_obj_t;

but after building the firmware it stills shows that in module 'IP_TOS' is not available.

[jimmo]

@AmeyAvhad You need to provide your own value of IP_TOS (like we do for e.g. IP_ADD_MEMBERSHIP).

Adding a tos field to the socket struct won't do anything. You need to set the tos field on the tcp (or udp) member of the pcb union.

[AmeyAvhad]

Hey @jimmo thanks for the suggestion I made some changes,

case IP_TOS: {
	 mp_int_t tos_value = mp_obj_get_int(args[3]);
         socket->pcb.ip->tos = (uint8_t)tos_value;
			break;
	}

and the build seems fine but when checking with wireshark the DSCP value doesnt seems to change.