David Cermak b5d13b9837 lwip/dhcpserver: Support for adding extra opts ...

This enables users appending an extra, user defined options in dhcp
server messages. Example of adding captive_portal option (160) to dhcp
offer message is provided:
* Add idf-lwip hook file (project makefile):
  idf_component_get_property(lwip lwip COMPONENT_LIB)
  target_compile_options(${lwip} PRIVATE "-I${PROJECT_DIR}/main")
  target_compile_definitions(${lwip} PRIVATE "-DESP_IDF_LWIP_HOOK_FILENAME=\"add_captive_portal.h\"")
* Implement appending (add_captive_portal.h):
  #pragma once
  #define LWIP_HOOK_DHCPS_POST_APPEND_OPTS(netif, dhcp, state, pp_opts) \
  if ((state)==DHCPOFFER) { *(pp_opts) = append_captive_portal_uri(*(pp_opts)); }
  static inline uint8_t *append_captive_portal_uri(uint8_t *optptr)
  {
    const static uint8_t DHCP_OPTION_CAPTIVE_PORTAL=160;
    const static char CAPTIVE_PORTAL_URI[]="my_uri";
    int size = sizeof(CAPTIVE_PORTAL_URI) - 1;
    *optptr++ = DHCP_OPTION_CAPTIVE_PORTAL;
    *optptr++ = size;
    for(int i = 0; i < size; ++i) {
        *optptr++ = CAPTIVE_PORTAL_URI[i];
    }
    return optptr;
  }

Merges https://github.com/espressif/esp-idf/pull/3308

2022-07-26 07:09:22 +00:00

..

dhcpserver.c

lwip/dhcpserver: Support for adding extra opts

2022-07-26 07:09:22 +00:00