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Page 10 of 11

Chapter 9

Page 190 SMTP  main program

#include <stdio.h>

#include "pico/stdlib.h"
#include "pico/cyw43_arch.h"

#include "setupWifi.h"

#include "lwip/apps/smtp.h"

void mailsent(void *arg, u8_t smtp_result, u16_t srv_err, err_t err)
{
    printf("mail (%p) sent with results: 0x%02x, 0x%04x, 0x%08x\n", arg,
           smtp_result, srv_err, err);
}

int main()
{
    stdio_init_all();
    connect();

    smtp_set_server_addr("iopress.info");
    smtp_set_server_port(25);  
    smtp_set_auth(NULL, NULL);
  smtp_send_mail("This email address is being protected from spambots. You need JavaScript enabled to view it.", "This email address is being protected from spambots. You need JavaScript enabled to view it.", "subject", "body", mailsent, NULL);
    while (true)
    {
        sleep_ms(10);
    }
}

Page 191 Full listing not in book

SMTP  CMakelists.txt

cmake_minimum_required(VERSION 3.13)
set(PICO_BOARD pico_w)
set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 17)

include(pico_sdk_import.cmake)
project(PicoW C CXX ASM)
pico_sdk_init()

add_executable(main
 main.c
)

target_include_directories(main PRIVATE ${CMAKE_CURRENT_LIST_DIR})

target_link_libraries(main pico_stdlib pico_cyw43_arch_lwip_threadsafe_background pico_lwip_smtp)  
pico_add_extra_outputs(main)

Page 192 Full listing not in book

SMTP lwipopts.h

#ifndef _LWIPOPTS_EXAMPLE_COMMONH_H
#define _LWIPOPTS_EXAMPLE_COMMONH_H

// Common settings used in most of the pico_w examples
// (see https://www.nongnu.org/lwip/2_1_x/group__lwip__opts.html for details)

// allow override in some examples
#ifndef NO_SYS
#define NO_SYS 1
#endif
// allow override in some examples
#ifndef LWIP_SOCKET
#define LWIP_SOCKET 0
#endif
#if PICO_CYW43_ARCH_POLL
#define MEM_LIBC_MALLOC 1
#else
// MEM_LIBC_MALLOC is incompatible with non polling versions
#define MEM_LIBC_MALLOC 0
#endif
#define MEM_ALIGNMENT 4
#define MEM_SIZE 4000
#define MEMP_NUM_TCP_SEG 32
#define MEMP_NUM_ARP_QUEUE 10
#define PBUF_POOL_SIZE 24
#define LWIP_ARP 1
#define LWIP_ETHERNET 1
#define LWIP_ICMP 1
#define LWIP_RAW 1
#define TCP_WND (8 * TCP_MSS)
#define TCP_MSS 1460
#define TCP_SND_BUF (8 * TCP_MSS)
#define TCP_SND_QUEUELEN ((4 * (TCP_SND_BUF) + (TCP_MSS - 1)) / (TCP_MSS))
#define LWIP_NETIF_STATUS_CALLBACK 1
#define LWIP_NETIF_LINK_CALLBACK 1
#define LWIP_NETIF_HOSTNAME 1
#define LWIP_NETCONN 0
#define MEM_STATS 0
#define SYS_STATS 0
#define MEMP_STATS 0
#define LINK_STATS 0
// #define ETH_PAD_SIZE 2
#define LWIP_CHKSUM_ALGORITHM 3
#define LWIP_DHCP 1
#define LWIP_IPV4 1
#define LWIP_TCP 1
#define LWIP_UDP 1
#define LWIP_DNS 1
#define LWIP_TCP_KEEPALIVE 1
#define LWIP_NETIF_TX_SINGLE_PBUF 1
#define DHCP_DOES_ARP_CHECK 0
#define LWIP_DHCP_DOES_ACD_CHECK 0

#ifndef NDEBUG
#define LWIP_DEBUG 1
#define LWIP_STATS 1
#define LWIP_STATS_DISPLAY 1
#endif

#define ETHARP_DEBUG LWIP_DBG_OFF
#define NETIF_DEBUG LWIP_DBG_OFF
#define PBUF_DEBUG LWIP_DBG_OFF
#define API_LIB_DEBUG LWIP_DBG_OFF
#define API_MSG_DEBUG LWIP_DBG_OFF
#define SOCKETS_DEBUG LWIP_DBG_OFF
#define ICMP_DEBUG LWIP_DBG_OFF
#define INET_DEBUG LWIP_DBG_OFF
#define IP_DEBUG LWIP_DBG_OFF
#define IP_REASS_DEBUG LWIP_DBG_OFF
#define RAW_DEBUG LWIP_DBG_OFF
#define MEM_DEBUG LWIP_DBG_OFF
#define MEMP_DEBUG LWIP_DBG_OFF
#define SYS_DEBUG LWIP_DBG_OFF
#define TCP_DEBUG LWIP_DBG_OFF
#define TCP_INPUT_DEBUG LWIP_DBG_OFF
#define TCP_OUTPUT_DEBUG LWIP_DBG_OFF
#define TCP_RTO_DEBUG LWIP_DBG_OFF
#define TCP_CWND_DEBUG LWIP_DBG_OFF
#define TCP_WND_DEBUG LWIP_DBG_OFF
#define TCP_FR_DEBUG LWIP_DBG_OFF
#define TCP_QLEN_DEBUG LWIP_DBG_OFF
#define TCP_RST_DEBUG LWIP_DBG_OFF
#define UDP_DEBUG LWIP_DBG_OFF
#define TCPIP_DEBUG LWIP_DBG_OFF
#define PPP_DEBUG LWIP_DBG_OFF
#define SLIP_DEBUG LWIP_DBG_OFF
#define DHCP_DEBUG LWIP_DBG_OFF

#define LWIP_DEBUG 1
#define SMTP_DEBUG LWIP_DBG_ON

#endif /* __LWIPOPTS_H__ */

Page 193 SMTPS main

#include <stdio.h>

#include "pico/stdlib.h"
#include "pico/cyw43_arch.h"

#include "setupWifi.h"
#include "lwip/altcp_tls.h"
#include "lwip/apps/smtp.h"

void mailsent(void *arg, u8_t smtp_result, u16_t srv_err, err_t err)
{
    printf("mail (%p) sent with results: 0x%02x, 0x%04x, 0x%08x\n", arg,
           smtp_result, srv_err, err);
}

int main()
{
    stdio_init_all();
    connect();
    struct altcp_tls_config *tls_config = altcp_tls_create_config_client(NULL, 0);
    smtp_set_tls_config(tls_config);

    smtp_set_server_addr("smtp.gmail.com");
    smtp_set_server_port(465);
    smtp_set_auth("gmailUSER", "App Password");

    smtp_send_mail("gmailUSER", "email address", "subject", "body", mailsent, NULL);
    while (true)
    {
        sleep_ms(10);
    }
}

Page 194 Full listing not in book

SMTPS mbedtls_config.h

//Hardware config
#define MBEDTLS_NO_PLATFORM_ENTROPY
#define MBEDTLS_ENTROPY_HARDWARE_ALT
#define MBEDTLS_HAVE_TIME

//error reporting
#define MBEDTLS_ERROR_C
//used by LwIP
#define MBEDTLS_ENTROPY_C
#define MBEDTLS_CTR_DRBG_C

//EC KEY EXCHANGE
#define MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED
#define MBEDTLS_ECDH_C
#define MBEDTLS_ECDSA_C
#define MBEDTLS_ECP_C

/* Short Weierstrass curves (supporting ECP, ECDH, ECDSA) */
#define MBEDTLS_ECP_DP_SECP192R1_ENABLED
#define MBEDTLS_ECP_DP_SECP224R1_ENABLED
#define MBEDTLS_ECP_DP_SECP256R1_ENABLED
#define MBEDTLS_ECP_DP_SECP384R1_ENABLED
#define MBEDTLS_ECP_DP_SECP521R1_ENABLED
#define MBEDTLS_ECP_DP_SECP192K1_ENABLED
#define MBEDTLS_ECP_DP_SECP224K1_ENABLED
#define MBEDTLS_ECP_DP_SECP256K1_ENABLED
#define MBEDTLS_ECP_DP_BP256R1_ENABLED
#define MBEDTLS_ECP_DP_BP384R1_ENABLED
#define MBEDTLS_ECP_DP_BP512R1_ENABLED

//RSA KEY EXCHANGE
#define MBEDTLS_KEY_EXCHANGE_RSA_ENABLED
#define MBEDTLS_RSA_C

//general key exchange
#define MBEDTLS_PKCS1_V15
#define MBEDTLS_BIGNUM_C
#define MBEDTLS_PK_C
#define MBEDTLS_PK_PARSE_C

//encryption
#define MBEDTLS_AES_C
#define MBEDTLS_CCM_C
#define MBEDTLS_CIPHER_MODE_CBC
#define MBEDTLS_AES_FEWER_TABLES
#define MBEDTLS_GCM_C

//certs
#define MBEDTLS_X509_CRT_PARSE_C
#define MBEDTLS_X509_USE_C
#define MBEDTLS_OID_C
#define MBEDTLS_ASN1_PARSE_C
#define MBEDTLS_ASN1_WRITE_C

//hash methods
#define MBEDTLS_SHA1_C
#define MBEDTLS_SHA224_C
#define MBEDTLS_SHA256_C
#define MBEDTLS_SHA512_C

//ECDHE-RSA-AES256-GCM-SHA384
//TLS
#define MBEDTLS_CIPHER_C
#define MBEDTLS_SSL_TLS_C
#define MBEDTLS_MD_C

//enable client modes and TLS
#define MBEDTLS_SSL_CLI_C
#define MBEDTLS_SSL_SERVER_NAME_INDICATION

//enable TLS 1.2
#define MBEDTLS_SSL_PROTO_TLS1_2

#include "/home/pi/pico/pico-sdk/lib/mbedtls/include/mbedtls/check_config.h"

Page 194 Full listing not in book

SMTPS lwipopts.h

#ifndef _LWIPOPTS_EXAMPLE_COMMONH_H
#define _LWIPOPTS_EXAMPLE_COMMONH_H

// Common settings used in most of the pico_w examples
// (see https://www.nongnu.org/lwip/2_1_x/group__lwip__opts.html for details)

// allow override in some examples
#ifndef NO_SYS
#define NO_SYS 1
#endif
// allow override in some examples
#ifndef LWIP_SOCKET
#define LWIP_SOCKET 0
#endif
#if PICO_CYW43_ARCH_POLL
#define MEM_LIBC_MALLOC 1
#else
// MEM_LIBC_MALLOC is incompatible with non polling versions
#define MEM_LIBC_MALLOC 0
#endif
#define MEM_ALIGNMENT 4
#define MEM_SIZE 4000
#define MEMP_NUM_TCP_SEG 32
#define MEMP_NUM_ARP_QUEUE 10
#define PBUF_POOL_SIZE 24
#define LWIP_ARP 1
#define LWIP_ETHERNET 1
#define LWIP_ICMP 1
#define LWIP_RAW 1
#define TCP_WND (8 * TCP_MSS)
#define TCP_MSS 1460
#define TCP_SND_BUF (8 * TCP_MSS)
#define TCP_SND_QUEUELEN ((4 * (TCP_SND_BUF) + (TCP_MSS - 1)) / (TCP_MSS))
#define LWIP_NETIF_STATUS_CALLBACK 1
#define LWIP_NETIF_LINK_CALLBACK 1
#define LWIP_NETIF_HOSTNAME 1
#define LWIP_NETCONN 0
#define MEM_STATS 0
#define SYS_STATS 0
#define MEMP_STATS 0
#define LINK_STATS 0
// #define ETH_PAD_SIZE 2
#define LWIP_CHKSUM_ALGORITHM 3
#define LWIP_DHCP 1
#define LWIP_IPV4 1
#define LWIP_TCP 1
#define LWIP_UDP 1
#define LWIP_DNS 1
#define LWIP_TCP_KEEPALIVE 1
#define LWIP_NETIF_TX_SINGLE_PBUF 1
#define DHCP_DOES_ARP_CHECK 0
#define LWIP_DHCP_DOES_ACD_CHECK 0

#ifndef NDEBUG
#define LWIP_DEBUG 1
#define LWIP_STATS 1
#define LWIP_STATS_DISPLAY 1
#endif

#define ETHARP_DEBUG LWIP_DBG_OFF
#define NETIF_DEBUG LWIP_DBG_OFF
#define PBUF_DEBUG LWIP_DBG_OFF
#define API_LIB_DEBUG LWIP_DBG_OFF
#define API_MSG_DEBUG LWIP_DBG_OFF
#define SOCKETS_DEBUG LWIP_DBG_OFF
#define ICMP_DEBUG LWIP_DBG_OFF
#define INET_DEBUG LWIP_DBG_OFF
#define IP_DEBUG LWIP_DBG_OFF
#define IP_REASS_DEBUG LWIP_DBG_OFF
#define RAW_DEBUG LWIP_DBG_OFF
#define MEM_DEBUG LWIP_DBG_OFF
#define MEMP_DEBUG LWIP_DBG_OFF
#define SYS_DEBUG LWIP_DBG_OFF
#define TCP_DEBUG LWIP_DBG_OFF
#define TCP_INPUT_DEBUG LWIP_DBG_OFF
#define TCP_OUTPUT_DEBUG LWIP_DBG_OFF
#define TCP_RTO_DEBUG LWIP_DBG_OFF
#define TCP_CWND_DEBUG LWIP_DBG_OFF
#define TCP_WND_DEBUG LWIP_DBG_OFF
#define TCP_FR_DEBUG LWIP_DBG_OFF
#define TCP_QLEN_DEBUG LWIP_DBG_OFF
#define TCP_RST_DEBUG LWIP_DBG_OFF
#define UDP_DEBUG LWIP_DBG_OFF
#define TCPIP_DEBUG LWIP_DBG_OFF
#define PPP_DEBUG LWIP_DBG_OFF
#define SLIP_DEBUG LWIP_DBG_OFF
#define DHCP_DEBUG LWIP_DBG_OFF

#undef TCP_WND
#define TCP_WND 16384
#undef MEM_SIZE
#define MEM_SIZE 8000

#define LWIP_ALTCP 1
#define LWIP_ALTCP_TLS 1
#define LWIP_ALTCP_TLS_MBEDTLS 1

#define LWIP_DEBUG 1
#define ALTCP_MBEDTLS_DEBUG LWIP_DBG_ON
#define SMTP_DEBUG LWIP_DBG_ON

#endif /* __LWIPOPTS_H__ */

Page 194 Full listing not in book

SMTPS CMakeLists.txt

cmake_minimum_required(VERSION 3.13)
set(PICO_BOARD pico_w)
set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 17)

include(pico_sdk_import.cmake)
project(PicoW C CXX ASM)
pico_sdk_init()

add_executable(main
main.c
)

target_include_directories(main PRIVATE ${CMAKE_CURRENT_LIST_DIR})

target_link_libraries(main pico_stdlib pico_cyw43_arch_lwip_threadsafe_background pico_lwip_mbedtls
pico_mbedtls pico_lwip_smtp)
pico_add_extra_outputs(main)