git.scottworley.com Git - tattlekey/blob - client/net.c

   1 /* tattlekey: A one-key UDP keyboard
   2  * Copyright (C) 2023  Scott Worley <scottworley@scottworley.com>
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  16  */
  17
  18 #include "net.h"
  19 #include "blink.h"
  20 #include "config.h"
  21
  22 #include "pico/cyw43_arch.h"
  23 #include "pico/rand.h"
  24
  25 #include "lwip/pbuf.h"
  26 #include "lwip/udp.h"
  27
  28 /* We only ever send to one address, and we only ever have one thread, so just
  29  * use one udp_pcb */
  30 static struct udp_pcb *the_pcb = NULL;
  31 static uint32_t epoch = 0;
  32
  33 static void net_local_init() {
  34   if (the_pcb)
  35     return;
  36
  37   new_epoch();
  38
  39   the_pcb = udp_new();
  40   if (!the_pcb)
  41     signal_error_by_blinking();
  42
  43   ip_addr_t ipaddr;
  44   if (ip4addr_aton(config_tattle_server_ip_address, &ipaddr) == 0)
  45     signal_error_by_blinking();
  46
  47   if (udp_connect(the_pcb, &ipaddr, config_tattle_port) != ERR_OK)
  48     signal_error_by_blinking();
  49 }
  50
  51 void new_epoch() { epoch = get_rand_32(); }
  52
  53 struct tattle_message_wire_format {
  54   u32_t epoch;
  55   u16_t sender;
  56   u16_t seq;
  57   u32_t ago;
  58 };
  59
  60 void send_report_packet(u16_t seq, u32_t ago) {
  61   cyw43_arch_lwip_begin();
  62
  63   net_local_init();
  64
  65   struct pbuf *p = pbuf_alloc(
  66       PBUF_TRANSPORT, sizeof(struct tattle_message_wire_format), PBUF_RAM);
  67   if (!p)
  68     signal_error_by_blinking();
  69
  70   struct tattle_message_wire_format *msg =
  71       (struct tattle_message_wire_format *)(p->payload);
  72   msg->epoch = htonl(epoch);
  73   msg->sender = htons(config_this_tattler_identity);
  74   msg->seq = htons(seq);
  75   msg->ago = htonl(ago);
  76
  77   if (udp_send(the_pcb, p) != ERR_OK)
  78     signal_error_by_blinking();
  79
  80   pbuf_free(p);
  81
  82   cyw43_arch_lwip_end();
  83 }